[top]
000
FXUS65 KTFX 151137
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
430 AM MST THU JAN 15 2009
AVIATION SECTION UPDATED...
.DISCUSSION...
THURSDAY THROUGH SATURDAY...COLDER TEMPERATURES GIVING WAY TO
SEASONABLY WARM TEMPERATURES THE NEXT FEW DAYS. CLEAR SKIES WILL
ALSO DOMINATE THE WEATHER SCENE AS THE RIDGE BUILDS OF THE COAST
OF THE PACIFIC NORTHWEST. NOT EXPECTING ANY SIGNIFICANT PRECIP
AFTER THE FRONT LEAVES THE EASTERN EDGE OF THE AREA ON THURSDAY.
MAIN FOCUS WITH THE ABOVE NORMAL TEMPERATURES WILL BE HYDROLOGIC
WITH SNOWMELT RUNOFF ENTERING THE DRAINAGE BASINS. SUK
SATURDAY NIGHT THROUGH TUESDAY NIGHT. STRONG PACIFIC UPPER RIDGE
WILL BE WELL ESTABLISHED ACROSS WESTERN US/SOUTHWEST CANADA BY
SATURDAY. ACCOMPANYING WARM AND DRY AIRMASS WILL KEEP SKIES MOSTLY
CLEAR AND ALLOW AFTN TEMPS TO SOAR TO NEAR-RECORD VALUES OF MID 50S
TO LOW 60S ACROSS THE PLAINS AND SOUTHWEST VALLEYS ON SUNDAY. UPPER
RIDGE AXIS WILL BE CENTERED ALONG THE CONTINENTAL DIVIDE BY MONDAY
AS RIDGE MAKES SLOW PROGRESSION INTO ERN MT ON TUES. MAX TEMPS WILL
REMAIN WELL ABOVE NORMAL ON MON AND TUES. GIVEN THE SEVERAL DAYS OF
UNSEASONABLY WARM CONDITIONS...THERE IS SOME CONCERN ABOUT POSSIBLE
FLOODING FROM RAPID MELTING AND ICE JAMS...SO WEEKEND SHIFTS WILL BE
CLOSELY MONITORING RIVER/CREEK LEVELS. WARANAUSKAS
WEDNESDAY AND THURSDAY...A DEEP LOW PRESSURE TROUGH IS EXPECTED TO
MOVE INTO THE PACIFIC NORTHWEST WEDNESDAY. SCATTERED SNOW SHOWERS
AND MUCH COLDER TEMPERATURES WILL DEVELOP FOR MUCH OF THE REGION
EARLY THURSDAY IF THE PRESENT MODEL SOLUTIONS ARE CORRECT. SAUCIER
&&
.AVIATION...
UPDATED 15/1130Z.
WEAK FRONTAL BOUNDARY CURRENTLY VCNTY KHVR TO KLWT WILL MAKE SLOW
PROGRESS TOWARD ERN MT THIS MORNING. LIGHT SNOW AND MVFR CEILINGS
ALONG THE FRONT HAVE BEEN DISSIPATING STEADILY PAST FEW HOURS AND
WILL END/IMPROVE TO VFR BY MID-MORNING. EARLIER CONCERNS ABOUT FOG
ARE FADING TOO...THOUGH KEPT TEMPO GROUP FOR 3 MI VIS AT KGTF TIL
14Z AS TEMP AND DEW POINT ARE STILL CLOSE. CLEARING SKIES WILL
CONTINUE TO EXPAND FROM WEST TO EAST AS STRONG HIGH PRESSURE RIDGE
BEGINS TO PUSH ACROSS THE NORTHERN ROCKIES. ACCOMPANYING AIRMASS
WILL GET PROGRESSIVELY WARMER AND DRIER FROM FRIDAY THRU THE
WEEKEND... RESULTING IN PROLONGED PERIOD OF MOSTLY CLEAR SKIES AND
LIGHT WINDS.
WARANAUSKAS
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 46 33 51 30 / 0 0 0 0
CTB 44 31 51 29 / 0 0 0 0
HLN 49 26 49 25 / 0 0 0 0
BZN 44 23 47 20 / 0 0 0 0
WEY 32 13 33 9 / 10 0 0 0
DLN 43 23 46 19 / 0 0 0 0
HVR 31 15 42 17 / 20 0 0 0
LWT 41 27 49 27 / 20 0 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUK
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...WARANAUSKAS
WEATHER.GOV/GREATFALLS
000
FXUS65 KTFX 151035
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
335 AM MST THU JAN 15 2009
.DISCUSSION...
THURSDAY THROUGH SATURDAY...COLDER TEMPERATURES GIVING WAY TO
SEASONABLY WARM TEMPERATURES THE NEXT FEW DAYS. CLEAR SKIES WILL
ALSO DOMINATE THE WEATHER SCENE AS THE RIDGE BUILDS OF THE COAST
OF THE PACIFIC NORTHWEST. NOT EXPECTING ANY SIGNIFICANT PRECIP
AFTER THE FRONT LEAVES THE EASTERN EDGE OF THE AREA ON THURSDAY.
MAIN FOCUS WITH THE ABOVE NORMAL TEMPERATURES WILL BE HYDROLOGIC
WITH SNOWMELT RUNOFF ENTERING THE DRAINAGE BASINS. SUK
SATURDAY NIGHT THROUGH TUESDAY NIGHT. STRONG PACIFIC UPPER RIDGE
WILL BE WELL ESTABLISHED ACROSS WESTERN US/SOUTHWEST CANADA BY
SATURDAY. ACCOMPANYING WARM AND DRY AIRMASS WILL KEEP SKIES MOSTLY
CLEAR AND ALLOW AFTN TEMPS TO SOAR TO NEAR-RECORD VALUES OF MID 50S
TO LOW 60S ACROSS THE PLAINS AND SOUTHWEST VALLEYS ON SUNDAY. UPPER
RIDGE AXIS WILL BE CENTERED ALONG THE CONTINENTAL DIVIDE BY MONDAY
AS RIDGE MAKES SLOW PROGRESSION INTO ERN MT ON TUES. MAX TEMPS WILL
REMAIN WELL ABOVE NORMAL ON MON AND TUES. GIVEN THE SEVERAL DAYS OF
UNSEASONABLY WARM CONDITIONS...THERE IS SOME CONCERN ABOUT POSSIBLE
FLOODING FROM RAPID MELTING AND ICE JAMS...SO WEEKEND SHIFTS WILL BE
CLOSELY MONITORING RIVER/CREEK LEVELS. WARANAUSKAS
WEDNESDAY AND THURSDAY...A DEEP LOW PRESSURE TROUGH IS EXPECTED TO
MOVE INTO THE PACIFIC NORTHWEST WEDNESDAY. SCATTERED SNOW SHOWERS
AND MUCH COLDER TEMPERATURES WILL DEVELOP FOR MUCH OF THE REGION
EARLY THURSDAY IF THE PRESENT MODEL SOLUTIONS ARE CORRECT. SAUCIER
&&
.AVIATION...
UPDATED 0545Z.
CONFIDENCE IN THE FORECAST FOR THE REST OF TONIGHT AND THURSDAY
MORNING IS ON THE LOW SIDE. LOCATIONS OVER THE PLAINS COULD SEE
ANYTHING FROM VFR CEILINGS/VISIBILITIES TO LIFR
CEILINGS/VISIBILITIES. TENDED TO MAKE IFR CEILINGS FAIRLY WIDESPREAD
LATE TONIGHT AND EARLY THURSDAY MORNING WITH AREAS OF IFR
VISIBILITIES. ALTHOUGH EXPECT KBZN/KHLN TO CONTINUE WITH VFR
CONDITIONS..VALLEY FOG IS NOT OUT OF THE QUESTION LATE TONIGHT AND
EARLY THURSDAY MORNING WITH LOCAL IFR CONDITIONS. OVER THE ENTIRE
AREA FEEL CONFIDENT IN VFR CONDITIONS BY THE AFTERNOON WITH CLEAR
SKIES THURSDAY EVENING. BLANK
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 46 33 51 30 / 0 0 0 0
CTB 44 31 51 29 / 0 0 0 0
HLN 49 26 49 25 / 0 0 0 0
BZN 44 23 47 20 / 0 0 0 0
WEY 32 13 33 9 / 10 0 0 0
DLN 43 23 46 19 / 0 0 0 0
HVR 31 15 42 17 / 20 0 0 0
LWT 41 27 49 27 / 20 0 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUK
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...WARANAUSKAS
WEATHER.GOV/GREATFALLS
000
FXUS65 KTFX 151035
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
335 AM MST THU JAN 15 2009
.DISCUSSION...
THURSDAY THROUGH SATURDAY...COLDER TEMPERATURES GIVING WAY TO
SEASONABLY WARM TEMPERATURES THE NEXT FEW DAYS. CLEAR SKIES WILL
ALSO DOMINATE THE WEATHER SCENE AS THE RIDGE BUILDS OF THE COAST
OF THE PACIFIC NORTHWEST. NOT EXPECTING ANY SIGNIFICANT PRECIP
AFTER THE FRONT LEAVES THE EASTERN EDGE OF THE AREA ON THURSDAY.
MAIN FOCUS WITH THE ABOVE NORMAL TEMPERATURES WILL BE HYDROLOGIC
WITH SNOWMELT RUNOFF ENTERING THE DRAINAGE BASINS. SUK
SATURDAY NIGHT THROUGH TUESDAY NIGHT. STRONG PACIFIC UPPER RIDGE
WILL BE WELL ESTABLISHED ACROSS WESTERN US/SOUTHWEST CANADA BY
SATURDAY. ACCOMPANYING WARM AND DRY AIRMASS WILL KEEP SKIES MOSTLY
CLEAR AND ALLOW AFTN TEMPS TO SOAR TO NEAR-RECORD VALUES OF MID 50S
TO LOW 60S ACROSS THE PLAINS AND SOUTHWEST VALLEYS ON SUNDAY. UPPER
RIDGE AXIS WILL BE CENTERED ALONG THE CONTINENTAL DIVIDE BY MONDAY
AS RIDGE MAKES SLOW PROGRESSION INTO ERN MT ON TUES. MAX TEMPS WILL
REMAIN WELL ABOVE NORMAL ON MON AND TUES. GIVEN THE SEVERAL DAYS OF
UNSEASONABLY WARM CONDITIONS...THERE IS SOME CONCERN ABOUT POSSIBLE
FLOODING FROM RAPID MELTING AND ICE JAMS...SO WEEKEND SHIFTS WILL BE
CLOSELY MONITORING RIVER/CREEK LEVELS. WARANAUSKAS
WEDNESDAY AND THURSDAY...A DEEP LOW PRESSURE TROUGH IS EXPECTED TO
MOVE INTO THE PACIFIC NORTHWEST WEDNESDAY. SCATTERED SNOW SHOWERS
AND MUCH COLDER TEMPERATURES WILL DEVELOP FOR MUCH OF THE REGION
EARLY THURSDAY IF THE PRESENT MODEL SOLUTIONS ARE CORRECT. SAUCIER
&&
.AVIATION...
UPDATED 0545Z.
CONFIDENCE IN THE FORECAST FOR THE REST OF TONIGHT AND THURSDAY
MORNING IS ON THE LOW SIDE. LOCATIONS OVER THE PLAINS COULD SEE
ANYTHING FROM VFR CEILINGS/VISIBILITIES TO LIFR
CEILINGS/VISIBILITIES. TENDED TO MAKE IFR CEILINGS FAIRLY WIDESPREAD
LATE TONIGHT AND EARLY THURSDAY MORNING WITH AREAS OF IFR
VISIBILITIES. ALTHOUGH EXPECT KBZN/KHLN TO CONTINUE WITH VFR
CONDITIONS..VALLEY FOG IS NOT OUT OF THE QUESTION LATE TONIGHT AND
EARLY THURSDAY MORNING WITH LOCAL IFR CONDITIONS. OVER THE ENTIRE
AREA FEEL CONFIDENT IN VFR CONDITIONS BY THE AFTERNOON WITH CLEAR
SKIES THURSDAY EVENING. BLANK
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 46 33 51 30 / 0 0 0 0
CTB 44 31 51 29 / 0 0 0 0
HLN 49 26 49 25 / 0 0 0 0
BZN 44 23 47 20 / 0 0 0 0
WEY 32 13 33 9 / 10 0 0 0
DLN 43 23 46 19 / 0 0 0 0
HVR 31 15 42 17 / 20 0 0 0
LWT 41 27 49 27 / 20 0 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUK
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...WARANAUSKAS
WEATHER.GOV/GREATFALLS
[top]
000
FXUS65 KBYZ 151024
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
324 AM MST THU JAN 15 2009
.SHORT TERM...VALID FOR TDY AND FRI...
WARMER TEMPERATURES ON TAP IN THE SHORT TERM BEGINNING THIS
AFTERNOON ACROSS THE WEST. ARCTIC FRONT THAT HAS BEEN SITUATED IN
A NORTH/SOUTH FASHION ACROSS CENTRAL MONTANA WILL BEGIN TO SHIFT
EAST THIS AFTERNOON IN RESPONSE TO HIGH PRESSURE BUILDING OVER
THE PACIFIC NORTHWEST. PERSISTENT BAND OF LIGHT TO MODERATE SNOW
THAT OCCURRED TODAY ALONG THE FRONT HAS DIMINISHED CONSIDERABLY
DURING THE PAST SEVERAL HOURS. ALTHOUGH LIGHT SNOW WILL CONTINUE
AT TIMES ALONG THE FRONT THIS MORNING...LITTLE IF ANY ADDITIONAL
ACCUMULATIONS ARE EXPECTED. AS A RESULT...HAVE CANCELLED ALL
ADVISORIES WITH THIS PACKAGE. MODELS DID NOT HANDLE THIS ARCTIC
TOO WELL AS THE FRONT DID MAKE IT TO LIVINGSTON BY LATE IN THE
DAY WEDNESDAY AND TEMPERATURES OUT EAST WERE COLDER.
HOWEVER...THE FRONT HAS SINCE RETREATED LIVINGSTON AS WINDS THERE
TURNED SOUTHWEST A FEW HOURS AGO. EAST OF THIS FRONT...BITTERLY
COLD TEMPERATURES ARE BEING REPORTED WITH BAKER CURRENTLY 12
BELOW ZERO.
HIGH PRESSURE RIDGE APPROACHING THE FORECAST AREA TODAY WILL HELP
TO ALLOW THE ARCTIC FRONT TO MAKE A RETREAT. HOWEVER...NOT MUCH
LEE-SIDE TROUGHING DEVELOPS TODAY SO THIS PROCESS WILL BE SLOW.
STILL BELIEVE TEMPERATURES WILL REACH THE UPPER 30S TO MIDDLE 40S
FROM BILLINGS WESTWARD. DO TO THE FACT THE TEMPERATURES WERE
COLDER THAN MODELS SHOWED...DID LOWER READINGS CENTRAL AND WEST A
FEW DEGREES FOR TODAY. OUT EAST...TEMPERATURES WILL CLIMB INTO
THE 20S BUT STILL BE VERY COLD ACROSS CARTER AND FALLON COUNTY
WHERE READINGS ARE ONLY EXPECTED TO RISE INTO THE TEENS. 700MB
WARM AIR ADVECTION MOVES OVER THE FORECAST AREA THIS
AFTERNOON...AND THIS COMBINED WITH THE FRONTAL BOUNDARY WILL
ALLOW FOR A CONTINUED SLIGHT CHANCE FOR VERY LIGHT SNOW ACROSS THE
EAST.
HIGH PRESSURE CONTINUES TO BUILD OVER THE FORECAST AREA FRIDAY
AND INTO THE WEEKEND. THIS WILL BRING WARMER TEMPERATURES AND DRY
CONDITIONS. MODELS STILL BRING A WEAK DISTURBANCE SOUTH OUT OF
CANADA FRIDAY AFTERNOON/NIGHT. MOISTURE CONTINUES TO LACK WITH
THIS SYSTEM AND AS A RESULT...HAVE REMOVED THE SLIGHT POP CHANCE
ACROSS THE FAR NORTHEAST ZONES FOR FRIDAY NIGHT. TEMPERATURES
WILL BE WELL ABOVE NORMAL ON FRIDAY WITH READINGS IN THE UPPER
40S TO LOWER 50S CENTRAL AND WEST AND LOWER 40S FAR EAST. HOOLEY
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
STRONG UPPER LEVEL RIDGE DOMINATES THE REGION THROUGH THE BULK OF
THE EXTENDED PERIOD...BRINGING A MUCH DRYER AIRMASS INTO THE
REGION. THE RIDGE BEGINS MOVING OVER THE AREA SATURDAY...AND
CONTINUING THROUGH MONDAY...AT THIS POINT THE RIDGE BEGINS TO
BREAK DOWN AND BE SHUNTED OF TO THE EAST AS ANOTHER ARCTIC BLAST
BEGINS PUSH SOUTHWARD. TIMING OF THIS BREAKDOWN VARIES A
BIT...WITH EC BRINGING COLD AIR INTO THE REGION WEDNESDAY
NIGHT...MUCH EARLIER EARLIER THAN THE GFS...BUT BOTH AGREE ON
RETURN OF COLD AIR.
IT APPEARS THAT WIND WILL CONTINUE TO BE AN ISSUE THROUGH THE
EXTENDED PERIOD...WITH PERSISTENT DRAINAGE WINDS IMPACTING THE
PLAINS AND POTENTIAL FOR PERIODS OF STRONG GAP WINDS IN THE UPPER
YELLOWSTONE AND STILLWATER VALLEYS...AS AN INVERSION SETS UP OVER
THE YELLOWSTONE PARK.
TEMPS SHOULD CLIMB THROUGH THE EARLY EXTENDED PERIOD...FROM THE
40S ON SATURDAY TO THE 50S BY THE BEGINNING OF NEXT WEEK. AS
RIDGE MOVES OFF TO THE EAST AND BEGINS TO BREAK DOWN
TUESDAY...TEMPS WILL BE A BIT COOLER...BUT STILL IN THE 40S AND
50S UNTIL THURSDAY...WHEN IT APPEARS ANOTHER ARCTIC FRONT WILL
PUSH ACROSS THE REGION DROPPING TEMPS TO THE TEENS AND 20S ACROSS
THE REGION. GILSTAD
&&
.AVIATION...
STATIONARY FRONT STILL IN PLACE JUST WEST OF BILLINGS...PRODUCING
LIGHT SNOW ALONG THE BOUNDARY. THE STATIONARY FRONT IS EXPECTED
TO SHIFT EASTWARD THIS MORNING...BRINGING LIGHT SNOW...WITH
LITTLE ACCUMULATION...TO MUCH OF THE REGION. MAINLY VFR TO MVFR
CONDITIONS ACROSS THE REGION...WITH VIS REDUCED ONLY SLIGHTLY IN
LIGHT SNOW...HOWEVER VERY ISOLATED HEAVIER SNOW ALONG THE FRONTAL
BOUNDARY MAY RESULT IN SOME IFR CONDITIONS.
SNOW ACROSS THE BEARTOOTH AND BIG HORN MOUNTAINS WILL TAPER OFF
THROUGH THE MORNING...AND MOUNTAIN OBSCURATIONS WILL BEGIN TO
CLEAR BY THIS AFTERNOON. GILSTAD
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 038 032/052 036/051 032/052 036/057 036/050 029/043
3/S 00/N 00/U 00/U 00/U 00/U 02/S
LVM 045 036/052 038/052 030/052 035/058 035/052 022/044
1/N 00/N 00/U 00/U 00/U 00/U 02/S
HDN 035 023/050 030/050 029/052 029/056 029/050 028/042
4/S 00/U 00/U 00/U 00/U 00/U 02/S
MLS 023 014/047 023/044 022/048 027/050 027/042 022/034
3/S 20/U 00/U 00/U 00/U 00/U 02/S
4BQ 028 019/047 027/052 026/051 028/055 028/049 026/041
4/S 20/U 00/U 00/U 00/U 00/U 01/B
BHK 011 010/041 019/042 020/046 023/049 023/042 021/034
3/S 30/U 01/U 00/U 00/U 00/U 01/N
SHR 034 023/049 030/052 025/052 026/057 026/050 026/044
5/O 00/U 00/U 00/U 00/U 00/U 02/S
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
[top]
000
FXUS65 KGGW 151020
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
320 AM MST THU JAN 15 2009
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
HIGHLY AMPLIFIED UPPER PATTERN WILL PERSIST OVER NORTH AMERICA
THRU THE SHORT TERM PERIOD...WITH EASTERN MONTANA REMAINING IN
NORTHWEST FLOW ALOFT IN BETWIXT THE WEST COAST RIDGE AND EAST
COAST TROF. SURFACE HIGH PRESSURE CURRENTLY OVER THE DAKOTAS WITH
LOW PRESSURE TO OUR WEST OVER CENTRAL TO WESTERN MONTANA. QUASI-
STATIONARY FRONT CURRENTLY IN THE VICINITY OF A CUT BANK TO GREAT
FALLS TO LIVINGSTON LINE. THIS BOUNDARY IS EXPECTED TO MOVE EAST
TODAY WHILE BECOMING VERY DIFFUSE IF NOT WASHING OUT ALTOGETHER.
COULD BE SOME LIGHT SNOW WITH THIS FEATURE BUT NOTHING SIGNIFICANT
IF ANY DOES OCCUR. WARM AIR ADVECTION IN THE WEST TODAY AS THE
BOUNDARY LIFTS THRU AS A WARM FRONT. WIND LOOKS TO REMAIN ON THE
LIGHT SIDE AS SURFACE TROF REMAINS OVER CENTRAL MONTANA AND THE
HIGH CURRENTLY OVER THE DAKOTAS DRIFTS SOUTHEAST ALLOWING PRESSURE
GRADIENT TO BE QUITE LOOSE. OTHER THAN LOCAL EFFECT EAST WIND AT
THE GLASGOW AIRPORT NOT FINDING ANY OTHER OBS SITES SHOWING MORE
THAN 7 MPH OF WIND...SO WILL DROP THE WIND CHILL ADVISORY AS WIND
SHOULD REMAIN ON THE LIGHT SIDE AND THE WIND AT THE GLASGOW
AIRPORT SHOULD BE DIMINISHING AS WELL. DECENT WIND ALOFT BUT NOT
REALLY SEEING MUCH IMPETUS FOR MIXING ASIDE FROM THE FAR WESTERN
QUARTER OR SO OF THE CWA. ALTHO THE WESTERN ZONES WILL WARM TODAY
THE CENTRAL AND EASTERN COUNTIES WILL REMAIN ON THE COLD SIDE AS
THE WARM AIR WILL HAVE TROUBLE MIXING DOWN. BROAD SURFACE TROF
MOVES IN TONIGHT BUT DOES NOT APPEAR SHARP ENUF TO RESULT IN MUCH
WIND. CLOUDS SHOULD BE EXITING TONIGHT LEAVING A CLEAR TO PARTLY
CLOUDY SKY. FRIDAY THE SURFACE TROF MOVES INTO THE WESTERN DAKOTAS
AND SHARPENS WHILE HIGH PRESSURE MOVES INTO WESTERN AND CENTRAL
MONTANA...PROVIDING A BETTER GRADIENT TO AID IN GENERATION OF
SURFACE WIND. BY AFTERNOON SHOULD BE ENUF TO MIX DOWN SOME WARMER
AIR. FRIDAY NIGHT A WEAK DISTURBANCE IN THE NORTHWEST FLOW ALOFT
MOVES ACROSS EASTERN MONTANA. ATMOSPHERE APPEARS MUCH TOO DRY FOR
ANY PRECIPITATION...BUT THIS CLIPPER WILL SERVE TO PUSH THE WARM
AIR BACK WEST FOR SATURDAY...MAKING SATURDAY A BIT COOLER THAN
FRIDAY. SHOULD BE DECENT SUN THO SO NOT A BAD DAY AS TEMPERATURES
SHOULD STILL BE ABOVE NORMAL.
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
MODELS ARE IN GOOD AGREEMENT WITH AN UPPER LEVEL RIDGE COVERING
THE WESTERN NORTH AMERICA THE NEXT SEVERAL DAYS. AT THIS
POINT...IT LOOKS LIKE THE RIDGE WILL LAST THROUGH TUESDAY WITH A
PATTERN CHANGE OCCURRING THE MIDDLE OF NEXT WEEK. DRY AND WARM
WEATHER WILL OCCUR FOR THE MOST PART. THE QUESTION WILL BE HOW
MUCH SNOW COVER AND LOW LEVEL INVERSIONS HOLD BACK TEMPERATURES.
THE RIDGE WILL HAVE A CLOSED UPPER HIGH THAT IS FORECASTED TO BE
IN THE PACIFIC NORTHWEST SUNDAY AND MONDAY. THAT HIGH STARTS
BREAKING DOWN ON TUESDAY. THE MODELS HAVE 850 MB TEMPERATURES
BETWEEN +12C AND +16C SUNDAY AND MONDAY. WITH SNOWCOVER AND LESS
THAN 9 HOURS OF DAYLIGHT...LOOK FOR AN INVERSION TO LIMIT
TEMPERATURES ESPECIALLY IN THE NORTHEAST ZONES. PETROLEUM AND
GARFIELD COUNTIES SHOULD HAVE BARE GROUND BY SUNDAY WHILE SW
PHILLIPS WILL LIKELY BE ABOVE THE INVERSION SO HIGHS IN THE 50S
LOOKS REASONABLE THERE. WILL KEEP HIGHS IN THE NORTHEAST AROUND 40.
WITH MELTING SNOW...PATCHY FOG WILL BE POSSIBLE EACH NIGHT. BEING
SEVERAL DAYS OUT...WILL NOT MENTION FOG YET.
RIDGE BREAKS DOWN BY MIDWEEK ALTHOUGH THE MODELS DIFFER SOMEWHAT IN
HOW THE HOW QUICKLY TO BREAK THE RIDGE DOWN. THEY AGREE ON TUESDAY
STAYING WARM WITH A STRONG COLD FRONT HITTING NORTHEAST MONTANA ON
WEDNESDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW ON WEDNESDAY FOR
NOW.
&&
.AVIATION...
A DECK OF MID LEVEL CLOUDS WILL LOWER THIS MORNING INTO LOW CLOUDS
AS A WARM FRONT APPROACHES NORTHEAST MONTANA. EXPECT CEILINGS TO
LOWER TO MVFR LEVELS THIS AFTERNOON AND REMAIN THERE THIS EVENING.
THERE IS A CHANCE OF SNOW TODAY. AS THE WARM FRONT MOVES THROUGH
THE TAF SITES TONIGHT...CEILINGS WILL RISE BACK UP TO VFR LEVELS. WINDS
WILL BE LIGHT EXCEPT FOR 10 KNOTS EAST WINDS AT KGGW EARLY THIS
MORNING. GFF
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
[top]
000
FXUS65 KMSO 151004
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
304 AM MST THU JAN 15 2009
.DISCUSSION...
TODAY THROUGH SATURDAY NIGHT...A STRONG RIDGE OF HIGH PRESSURE ALONG
THE PACIFIC COAST WILL GRADUALLY MOVE EASTWARD DURING THE NEXT
SEVERAL DAYS. THIS RIDGE IS ANTICIPATED TO BRING MOSTLY CLEAR SKIES
AND WARM TEMPERATURES OVER HIGH TERRAIN DURING THIS TIME.
HOWEVER...THE STRONG STABILIZING EFFECT OF THIS RIDGE...COUPLED WITH
WEAK MIXING WITHIN MOST AREA VALLEYS...WILL ALLOW INVERSIONS TO
DEVELOP AND STRENGTHEN OVER TIME. FOG AND FREEZING FOG ARE
ANTICIPATED TO BECOME WIDESPREAD WITHIN NORTHWEST MONTANA
VALLEYS...LATER SPREADING TO OTHER VALLEYS IN WESTERN MONTANA AND
NORTH CENTRAL IDAHO. LOWER VISIBILITIES WILL HAVE AN IMPACT ON
TRAVEL AND AVIATION...AS WELL AS FOG AND FREEZING FOG THAT SETTLES
ON AREA ROADS WHEN THE AIR TEMPERATURE IS BELOW FREEZING. THE DEEPER
AND NARROWER THE VALLEY...THE MORE LIKELY THAT FOG AND FREEZING FOG
WILL DEVELOP AND PERSIST. SOME OF THE FOG LAYERS MAY LIFT TO LOW
LEVEL STRATUS AT SOME LOCATIONS...PARTICULARLY IN NORTHWEST MONTANA.
AS AREA INVERSIONS INTENSIFY OVER TIME...TEMPERATURES WILL
SIMULTANEOUSLY COOL. BY SATURDAY...SOME VALLEYS MAY EXPERIENCE
AFTERNOON TEMPERATURES THAT ARE 10 TO 20 DEGREES COLDER THAN
SURROUNDING TOPS. NO PRECIPITATION IS ANTICIPATED ACROSS THE REGION
THROUGH SATURDAY NIGHT.
SUNDAY THROUGH TUESDAY...STRONG RIDGE WILL CONTINUE TO MAINTAIN ITS
GRIP ACROSS THE WESTERN U.S. THE RIDGE AXIS WILL MOVE OVER THE
NORTHERN ROCKIES. STRONG INVERSIONS UNDER THIS RIDGE AXIS WILL
ENHANCE WIDESPREAD FREEZING FOG IN THE VALLEYS.
WEDNESDAY THROUGH THURSDAY...MODELS ARE INDICATING A CHANGE BY
INTRODUCING A TROUGH ALONG THE WEST COAST ON WEDNESDAY WHICH WILL
PUSH THE RIDGE TO THE EAST. BY THURSDAY MODELS ARE BRINGING THE
TROUGH INTO NORTH CENTRAL IDAHO AND WESTERN MONTANA WITH A CHANCE OF
SOME SHOWERS...ALONG WITH MIXING THE STAGNATE AIR OUT OF THE VALLEYS.
AIR STAGNATION...IDAHO...AIR QUALITY IS EXPECTED TO DETERIORATE
TODAY THROUGH MONDAY ACROSS CENTRAL IDAHO AS POLLUTANTS BECOME
TRAPPED IN THE VALLEYS UNDER DEVELOPING STRONG INVERSIONS.
&&
.AVIATION...
A STRONG RIDGE OF HIGH PRESSURE WILL IMPACT AVIATION FOR THE NEXT 24
HOURS AND BEYOND. WEAK MIXING AND HIGH ATMOSPHERIC STABILITY WILL BE
PRESENT WITHIN VALLEYS ACROSS THE REGION. MVFR FLIGHT CONDITIONS FOR
FOG...FREEZING FOG...AND LOW STRATUS MAY BE ENCOUNTERED NEAR ALL
AREA TERMINALS DURING THIS TIME...PARTICULARLY THROUGH 15/1800Z...
AND AGAIN AFTER 16/0600Z. OTHERWISE...VFR FLIGHT CONDITIONS ARE
ANTICIPATED TO PREVAIL.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&
$$
SHORT TERM...ZUMPFE
LONG TERM....KOLATA
AVIATION...ZUMPFE
000
FXUS65 KTFX 150546
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 PM MST WED JAN 14 2009
.UPDATE...
FRONTAL BOUNDARY REMAINS STALLED ALONG THE IMMEDIATE EAST SLOPES
OF THE ROCKIES THIS EVENING...EXTENDING EASTWARD INTO CENTRAL MT
ALONG THE LITTLE BELTS THEN SOUTH THROUGH LIVINGSTON. EXPECT THIS
BOUNDARY TO MOVE LITTLE THROUGH THE NEXT SEVERAL HRS THEN BEGIN TO
LIFT EAST BY THURSDAY MORNING. THIS WILL LEAVE MUCH OF NORTH
CENTRAL MT...ESPECIALLY AREAS EAST OF I-15...IN THE COLDER AIRMASS
THROUGH TONIGHT BEFORE THE COLD AIRMASS RETREATS. AREA OF LIGHT
SNOW ASSOCIATED WITH ENERGY WITHIN NW FLOW ALOFT OVER EAST ZONES
HAS BEEN SLOWLY DIMINISHING THIS EVENING AND EXPECT THIS TREND TO
CONTINUE THROUGH TONIGHT WITH ANY ADDITIONAL ACCUMULATIONS LESS
THAN AN INCH AND MAINLY CONFINED TO AREAS OF FERGUS AND BLAINE
COUNTIES. HAVE MADE SOME MINOR ADJUSTMENTS TO POPS AND WILL EXPIRE
THE WINTER WX ADVISORY WITH THE UPDATE THIS EVENING. RADAR DOES
SHOW SOME WEAK RETURNS FARTHER WEST ALONG THE I-15 CORRIDOR AND
WILL ADD A MENTION OF FLURRIES FOR THESE AREAS AS THE SHALLOW
MOIST/COLD AIRMASS WILL CONTINUE TO SUPPORT LOW CLOUDS AND POSSIBLE
LIGHT FLURRIES. ANOTHER BENEFIT OF THE SHALLOW/COLD/MOIST AIRMASS
ACROSS WESTERN PORTIONS OF NORTH CENTRAL MT IS THE POSSIBILITY FOR
PATCHY FOG AND LOW CLOUDS AND WILL ADD THE MENTION OF THIS TONIGHT AS
WELL. OUTSIDE OF THE THE COLD AIRMASS...TEMPS ARE RELATIVELY MILD
ACROSS MUCH OF WESTERN AND SW MT AND HAVE MADE SOME ADJUSTMENTS TO
LOWS TONIGHT FOR SOME LOCATIONS IN SW ZONES. HOENISCH
&&
.AVIATION...
UPDATED 0545Z.
CONFIDENCE IN THE FORECAST FOR THE REST OF TONIGHT AND THURSDAY
MORNING IS ON THE LOW SIDE. LOCATIONS OVER THE PLAINS COULD SEE
ANYTHING FROM VFR CEILINGS/VISIBILITIES TO LIFR
CEILINGS/VISIBILITIES. TENDED TO MAKE IFR CEILINGS FAIRLY WIDESPREAD
LATE TONIGHT AND EARLY THURSDAY MORNING WITH AREAS OF IFR
VISIBILITES. ALTHOUGH EXPECT KBZN/KHLN TO CONTINUE WITH VFR
CONDITIONS..VALLEY FOG IS NOT OUT OF THE QUESTION LATE TONIGHT AND
EARLY THURSDAY MORNING WITH LOCAL IFR CONDITIONS. OVER THE ENTIRE
AREA FEEL CONFIDENT IN VFR CONDITIONS BY THE AFTERNOON WITH CLEAR
SKIES THURSDAY EVENING. BLANK
&&
.PREV DISCUSSION...
/ISSUED 500 PM MST WED JAN 14 2009/
TONIGHT THROUGH FRIDAY...BACK DOOR COLD FRONT REMAINS NEARLY
STATIONARY IN WESTERN PORTIONS OF NORTH CENTRAL MONTANA. EAST OF
THIS FEATURE TEMPERATURES REMAIN IN THE TEENS AND 20S...AND SINGLE
DIGITS IN THE FAR NORTHEAST...WITH 40S TO THE WEST OF THE FRONT.
LIGHT SNOW WILL CONTINUE TO FALL ACROSS MY EASTERN PLAINS THROUGH
THIS EVENING WITH PERHAPS ANOTHER INCH OR SO OF ACCUMULATION...SO
WILL CONTINUE THE WINTER WEATHER ADVISORY. OVERNIGHT TEMPERATURES
WILL REMAIN TRICKY AS MODELS SUGGEST THE FRONT COULD BEGIN TO DRIFT
EAST OVERNIGHT WITH TEMPERATURES RISING IN ITS WAKE. FRONT BEGINS
TO MOVE OUT FOR SURE ON THURSDAY WITH TEMPERATURES RISING A GOOD 20
DEGREES ACROSS ALL BUT FAR NORTHEAST PORTIONS OF MY CWA. MY FAR
EASTERN ZONES ARE ALSO EXPECTED TO CONTINUE TO HAVE A CHANCE OF
WARM ADVECTION PRECIPITATION TOMORROW AS THE FRONT LIFTS OUT OF
THE AREA. BY LATE THURSDAY NIGHT THE FRONT IS EXPECTED TO
COMPLETELY EXIT CENTRAL MONTANA WITH MY ENTIRE FORECAST AREA
COMING UNDER THE INFLUENCE OF A STRONG UPPER LEVEL RIDGE THAT WILL
PERSIST INTO THE WEEKEND. AM EXPECTING MOSTLY CLEAR SKIES WITH
TEMPERATURES RISING WELL ABOVE SEASONAL AVERAGES. MPJ
FRIDAY NIGHT THROUGH MONDAY NIGHT. ALL MODELS STILL ON TRACK IN
SHOWING ARRIVAL OF STRONG PACIFIC UPPER RIDGE OVER THE WESTERN US
DURING THIS PERIOD. LEADING EDGE OF THE RIDGE EXTENDS ALL THE WAY
INTO ERN MT BY FRIDAY NIGHT. AIRMASS ACROSS CENTRAL AND SOUTHWEST MT
WILL BECOME PROGRESSIVELY DRIER AND WARMER THROUGH THE WEEKEND. A
WEAK SHORTWAVE TROF COMES DOWN THE EAST SIDE OF THE RIDGE ON SAT BUT
SHOULD PRODUCE LITTLE MORE THAN SLIGHTLY INCREASED HIGH CLOUD COVER
OVER THE REGION. UPPER RIDGE AXIS WILL BE CENTERED ALONG THE
CONTINENTAL DIVIDE BY MONDAY AS RIDGE MAKE SLOW PROGRESSION TO THE
EAST. KEPT PREVIOUS SHIFTS DECISION TO GO SEVERAL DEGREES ABOVE
GUIDANCE FOR MAX TEMPS ON SAT AND SUN AS CLEAR TO SCATTERED SKIES
WILL PROVIDE EXTENDED PERIODS OF SUNSHINE. THIS WILL CAUSE RAPID
MELTING OF CURRENT SNOW COVER IN THE PLAINS ALLOWING LOW LEVEL TEMPS
TO WARM SIGNIFICANTLY...AS EVIDENCED BY MODEL FORECASTS OF TEMPS IN
LOW-MID 50S UP TO 850 MB/5000 FT ELEV ON SUN AFTN. WARANAUSKAS
TUESDAY AND WEDNESDAY...CURRENT MODELS DEPICT A HIGH PRESSURE RIDGE
OVER CENTRAL MONTANA WHICH WILL GIVE WAY TO A PACIFIC LOW PRESSURE
TROUGH EXPECTED TO MOVE INTO THE REGION BY THURSDAY AFTERNOON. A
CHANCE FOR PRECIPITATION FOR MUCH OF THE CWA THURSDAY AND THURSDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL AS THE FRONT
ADVANCES INTO THE REGION. SAUCIER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 16 47 32 52 / 10 0 0 0
CTB 18 44 30 53 / 10 0 0 0
HLN 29 50 24 52 / 10 0 0 0
BZN 26 45 23 49 / 10 0 0 0
WEY 16 29 12 32 / 10 10 0 0
DLN 30 45 23 49 / 0 0 0 0
HVR -5 30 14 43 / 70 20 0 0
LWT 16 40 26 50 / 80 20 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MPJ
LONG TERM...WARANAUSKAS
AVIATION...BLANK
WEATHER.GOV/GREATFALLS
000
FXUS65 KTFX 150414
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
914 PM MST WED JAN 14 2009
.UPDATE...
FRONTAL BOUNDARY REMAINS STALLED ALONG THE IMMEDIATE EAST SLOPES
OF THE ROCKIES THIS EVENING...EXTENDING EASTWARD INTO CENTRAL MT
ALONG THE LITTLE BELTS THEN SOUTH THROUGH LIVINGSTON. EXPECT THIS
BOUNDARY TO MOVE LITTLE THROUGH THE NEXT SEVERAL HRS THEN BEGIN TO
LIFT EAST BY THURSDAY MORNING. THIS WILL LEAVE MUCH OF NORTH
CENTRAL MT...ESPECIALLY AREAS EAST OF I-15...IN THE COLDER AIRMASS
THROUGH TONIGHT BEFORE THE COLD AIRMASS RETREATS. AREA OF LIGHT
SNOW ASSOCIATED WITH ENERGY WITHIN NW FLOW ALOFT OVER EAST ZONES
HAS BEEN SLOWLY DIMINISHING THIS EVENING AND EXPECT THIS TREND TO
CONTINUE THROUGH TONIGHT WITH ANY ADDITIONAL ACCUMULATIONS LESS
THAN AN INCH AND MAINLY CONFINED TO AREAS OF FERGUS AND BLAINE
COUNTIES. HAVE MADE SOME MINOR ADJUSTMENTS TO POPS AND WILL EXPIRE
THE WINTER WX ADVISORY WITH THE UPDATE THIS EVENING. RADAR DOES
SHOW SOME WEAK RETURNS FARTHER WEST ALONG THE I-15 CORRIDOR AND
WILL ADD A MENTION OF FLURRIES FOR THESE AREAS AS THE SHALLOW
MOIST/COLD AIRMASS WILL CONTINUE TO SUPPORT LOW CLOUDS AND POSSIBLE
LIGHT FLURRIES. ANOTHER BENEFIT OF THE SHALLOW/COLD/MOIST AIRMASS ACROSS
WESTERN PORTIONS OF NORTH CENTRAL MT IS THE POSSIBILITY FOR PATCHY
FOG AND LOW CLOUDS AND WILL ADD THE MENTION OF THIS TONIGHT AS
WELL. OUTSIDE OF THE THE COLD AIRMASS...TEMPS ARE RELATIVELY MILD
ACROSS MUCH OF WESTERN AND SW MT AND HAVE MADE SOME ADJUSTMENTS TO
LOWS TONIGHT FOR SOME LOCATIONS IN SW ZONES. HOENISCH
&&
.AVIATION...
UPDATED 0000Z.
OVERALL CONFIDENCE IN THE FORECAST IS LOW. FOR SOUTHWEST MONTANA
EXPECT VFR CONDITIONS THROUGH 07Z. AFTER THAT THERE IS THE POTENTIAL
FOR VALLEY FOG WITH CONDITIONS LOCALLY LIFR. FEEL THREAT OF FOG IS
LOW ENOUGH TO JUST MENTION VICINITY FOG IN THE TAFS FOR KBZN AND
KHLN. OVER THE PLAINS EXPECT WIDESPREAD CEILINGS IN THE LOW MVFR OR
IFR RANGE THROUGH MIDNIGHT. EXPECT WIDESPREAD IFR VISIBILITIES AT
KHVR THROUGH MUCH OF THE NIGHT IN SNOW. HOWEVER AT KLWT/KGTF/KCTB
COULD ALSO SEE IFR VISIBILITIES AND FEEL THERE IS ENOUGH OF A THREAT
THAT HAVE GONE WITH TEMPO GROUPS THROUGH MIDNIGHT. FOR LATE TONIGHT
INTO THURSDAY MORNING THERE IS A HUGE DIFFERENCE AMONGST GUIDANCE
WITH SOME GUIDANCE FORECASTING LIFR CEILINGS AND VISIBILITIES AND
OTHER GUIDANCE FORECASTING VFR CEILINGS AND VISIBILITIES. HAVE
TENDED TO LEAN TOWARDS THE FORMER FOR THE KHVR/KLWT TAFS AND THE
LATTER FOR THE KGTF/KCTB TAFS. HOWEVER WOULD NOT BE TOTALLY
SURPRISED TO SEE LIFR CEILINGS AND VISIBILITIES AT KCTB AND KGTF
INTO EARLY THURSDAY MORNING. DO FEEL PRETTY CONFIDENT THAT
KLWT/KGTF/KCTB WILL SEE VFR CONDITIONS BY NOON THURSDAY. EXPECT
WINDS TO STAY GENERALLY LESS THAN 15 KNOTS THROUGH THE PERIOD. BLANK
&&
.PREV DISCUSSION...
/ISSUED 500 PM MST WED JAN 14 2009/
TONIGHT THROUGH FRIDAY...BACK DOOR COLD FRONT REMAINS NEARLY
STATIONARY IN WESTERN PORTIONS OF NORTH CENTRAL MONTANA. EAST OF
THIS FEATURE TEMPERATURES REMAIN IN THE TEENS AND 20S...AND SINGLE
DIGITS IN THE FAR NORTHEAST...WITH 40S TO THE WEST OF THE FRONT.
LIGHT SNOW WILL CONTINUE TO FALL ACROSS MY EASTERN PLAINS THROUGH
THIS EVENING WITH PERHAPS ANOTHER INCH OR SO OF ACCUMULATION...SO
WILL CONTINUE THE WINTER WEATHER ADVISORY. OVERNIGHT TEMPERATURES
WILL REMAIN TRICKY AS MODELS SUGGEST THE FRONT COULD BEGIN TO DRIFT
EAST OVERNIGHT WITH TEMPERATURES RISING IN ITS WAKE. FRONT BEGINS
TO MOVE OUT FOR SURE ON THURSDAY WITH TEMPERATURES RISING A GOOD 20
DEGREES ACROSS ALL BUT FAR NORTHEAST PORTIONS OF MY CWA. MY FAR
EASTERN ZONES ARE ALSO EXPECTED TO CONTINUE TO HAVE A CHANCE OF
WARM ADVECTION PRECIPITATION TOMORROW AS THE FRONT LIFTS OUT OF
THE AREA. BY LATE THURSDAY NIGHT THE FRONT IS EXPECTED TO
COMPLETELY EXIT CENTRAL MONTANA WITH MY ENTIRE FORECAST AREA
COMING UNDER THE INFLUENCE OF A STRONG UPPER LEVEL RIDGE THAT WILL
PERSIST INTO THE WEEKEND. AM EXPECTING MOSTLY CLEAR SKIES WITH
TEMPERATURES RISING WELL ABOVE SEASONAL AVERAGES. MPJ
FRIDAY NIGHT THROUGH MONDAY NIGHT. ALL MODELS STILL ON TRACK IN
SHOWING ARRIVAL OF STRONG PACIFIC UPPER RIDGE OVER THE WESTERN US
DURING THIS PERIOD. LEADING EDGE OF THE RIDGE EXTENDS ALL THE WAY
INTO ERN MT BY FRIDAY NIGHT. AIRMASS ACROSS CENTRAL AND SOUTHWEST MT
WILL BECOME PROGRESSIVELY DRIER AND WARMER THROUGH THE WEEKEND. A
WEAK SHORTWAVE TROF COMES DOWN THE EAST SIDE OF THE RIDGE ON SAT BUT
SHOULD PRODUCE LITTLE MORE THAN SLIGHTLY INCREASED HIGH CLOUD COVER
OVER THE REGION. UPPER RIDGE AXIS WILL BE CENTERED ALONG THE
CONTINENTAL DIVIDE BY MONDAY AS RIDGE MAKE SLOW PROGRESSION TO THE
EAST. KEPT PREVIOUS SHIFTS DECISION TO GO SEVERAL DEGREES ABOVE
GUIDANCE FOR MAX TEMPS ON SAT AND SUN AS CLEAR TO SCATTERED SKIES
WILL PROVIDE EXTENDED PERIODS OF SUNSHINE. THIS WILL CAUSE RAPID
MELTING OF CURRENT SNOW COVER IN THE PLAINS ALLOWING LOW LEVEL TEMPS
TO WARM SIGNIFICANTLY...AS EVIDENCED BY MODEL FORECASTS OF TEMPS IN
LOW-MID 50S UP TO 850 MB/5000 FT ELEV ON SUN AFTN. WARANAUSKAS
TUESDAY AND WEDNESDAY...CURRENT MODELS DEPICT A HIGH PRESSURE RIDGE
OVER CENTRAL MONTANA WHICH WILL GIVE WAY TO A PACIFIC LOW PRESSURE
TROUGH EXPECTED TO MOVE INTO THE REGION BY THURSDAY AFTERNOON. A
CHANCE FOR PRECIPITATION FOR MUCH OF THE CWA THURSDAY AND THURSDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL AS THE FRONT
ADVANCES INTO THE REGION. SAUCIER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 16 47 32 52 / 10 0 0 0
CTB 18 44 30 53 / 10 0 0 0
HLN 29 50 24 52 / 10 0 0 0
BZN 26 45 23 49 / 10 0 0 0
WEY 16 29 12 32 / 10 10 0 0
DLN 30 45 23 49 / 0 0 0 0
HVR -5 30 14 43 / 70 20 0 0
LWT 16 40 26 50 / 80 20 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MPJ
LONG TERM...WARANAUSKAS
AVIATION...BLANK
WEATHER.GOV/GREATFALLS
000
FXUS65 KMSO 150351
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
851 PM MST WED JAN 14 2009
.UPDATE...INCREASED LOWS TONIGHT IN WESTERN MONTANA.
&&
.DISCUSSION...SATELLITE IS SHOWING CLOUDS CONTINUING TO STREAM
INTO NORTHWEST MONTANA. SOME BREAKS HAVE DEVELOPED IN THE
APPROACHING CLOUD COVER BUT HIGH SURFACE DEW POINTS IN WESTERN
MONTANA FROM MELTING SNOW SHOULD HELP KEEP TEMPERATURES UP AS
THESE BREAKS PASS BY. THE POTENTIAL FOR FOG TO DEVELOP STILL
APPEARS TO BE ON TRACK.
&&
.AVIATION...NORTHWESTERLY FLOW ALOFT WILL CONTINUE THROUGH THE END
OF THE WEEK. CLOUDS WILL PASS THROUGH THE AREA OVERNIGHT. BREAKS
IN THE CLOUD COVER WILL LIKELY RESULT IN FOG DEVELOPMENT TOWARDS
MORNING. NORTH CENTRAL IDAHO AND NORTHWEST MONTANA WILL BE THE
MOST AFFECTED BY THIS FOG THROUGH THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 250 PM MST WED JAN 14 2009/
..INCREASING FOG AND AIR QUALITY CONCERNS ARE LIKELY FROM
THURSDAY NIGHT THROUGH MONDAY...
DISCUSSION...
TONIGHT THROUGH FRIDAY...THE NORTHERN ROCKIES REGION WILL CONTINUE
TO BE UNDER A NORTHWESTERLY FLOW ALOFT THROUGH THE END OF THE WEEK
AS HIGH PRESSURE CONTINUES ON THE WEST COAST. MOISTURE CONTINUES
TO PASS OVER THE APEX OF THE RIDGE ALLOWING FOR CLOUD COVER TO
PASS OVER NORTHERN IDAHO AND WESTERN MONTANA. FOR THE MOST PART
THE CLOUDS HAVE BEEN EITHER HIGH ENOUGH OR THERE HAVE BEEN ENOUGH
CLEAR PERIODS THAT NORTHWEST MONTANA HAS BEEN EXPERIENCING FOG.
CENTRAL IDAHO HAS NOT SEEN AS MUCH CLOUD COVER AS WESTERN MONTANA
AND HAS HAD MORE WIDESPREAD FOG DEVELOPMENT. THE HIGH PRESSURE
RIDGE WILL SLOWLY MOVE EASTWARD ALLOWING FOR STRENGTHENING
INVERSIONS AND INCREASING FOG COVERAGE. SKY COVER WILL PUT A
DAMPER ON THE FULL INVERSION POTENTIAL...BUT CONDITIONS CONTINUE
TO LOOK FAVORABLE FOR INCREASED FOG COVERAGE...ESPECIALLY IN IDAHO
AND NORTHWEST MONTANA.
SATURDAY THROUGH TUESDAY...STRONG RIDGE WILL CONTINUE TO MAINTAIN
ITS GRIP ACROSS THE WESTERN U.S. THE RIDGE AXIS WILL MOVE OVER THE
NORTHERN ROCKIES. STRONG INVERSIONS UNDER THIS RIDGE AXIS WILL
ENHANCE WIDESPREAD FREEZING FOG IN THE VALLEYS. THE FOG HAS THE
POTENTIAL TO BE A FEW THOUSAND FEET THICK AND APPROACH THE RIDGE TOPS
DURING THE COURSE OF THE ENTIRE DAY AND NIGHT.
WEDNESDAY...MODELS ARE INDICATING A SUBTLE CHANGE BY INTRODUCING A
WEAK TROF ALONG THE WEST COAST WHICH WILL PUSH THE RIDGE TO THE
EAST. A FEW SHOWERS MAY BE POSSIBLE IN NORTHWEST MONTANA.
AIR STAGNATION...IDAHO...AIR QUALITY IS EXPECTED TO DETERIORATE
THURSDAY THROUGH MONDAY ACROSS CENTRAL IDAHO AS POLLUTANTS BECOME
TRAPPED IN THE VALLEYS UNDER DEVELOPING STRONG INVERSIONS.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&
$$
SHORT TERM...KITSMILLER
LONG TERM....RPN
AVIATION...MSJ
000
FXUS65 KBYZ 150347
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
847 PM MST WED JAN 14 2009
.SHORT TERM...VALID FOR THU AND FRI...
MADE A NUMBER OF UPDATES TO THE OVERNIGHT FORECAST AS STATIONARY
FRONT HAS BEGUN TO SHIFT WESTWARD. FRONT HAS PUSHED INTO
LIVINGSTON AS WINDS HAVE GONE NORTHEAST THERE. FRONT WILL BEGIN
TO PUSH BACK TO THE EAST OVERNIGHT AS STRONG MID LEVEL WARM AIR
ADVECTION MOVES IN FROM THE WEST. WITH FRONT SHIFTING WEST...BAND
OF LIGHT TO MODERATE SNOW WILL ALSO SHIFT WESTWARD. 1 TO 2 INCHES
OF SNOW ACCUMULATION WILL BE POSSIBLE OVERNIGHT AS THIS BAND OF
SNOW CONTINUES TO MOVE WESTWARD. THE HEAVIEST SNOW FALL WILL BE
LOCATED FROM MUSSELSHELL COUNTY SOUTHEAST THROUGH BIG HORN AND
SHERIDAN COUNTIES WHERE ADDITIONAL 2 TO 4 INCHES WILL BE POSSIBLE
OVERNIGHT. UPDATED MIN TEMPS ESPECIALLY ACROSS SOUTHEAST MONTANA
AS ARCTIC HIGH PRESSURE SYSTEM SETTLES IN OVER WESTERN NORTH
DAKOTA. SKIES HAVE CLEARED OVER KBHK AND TEMPS HAVE FALLEN TO THE
TEENS BELOW ZERO WITH LIGHT WINDS. WILL LEAVE CURRENT WINTER
WEATHER ADVISORY IN EFFECT AS WORDING AND TIMING APPEAR
REPRESENTATIVE. SCHUKNECHT/RICHMOND
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
SATURDAY THROUGH MONDAY WILL SEE A HIGH AMPLITUDE RIDGE MOVE
ACROSS THE PACIFIC NORTHWEST INTO CENTRAL MONTANA BRINGING A
MILD...DRY WEATHER PATTERN TO THE AREA. STRONG INVERSIONS OVER
YELLOWSTONE PARK AND SOUTHEAST IDAHO SHOULD SUPPORT EPISODES OF
GAP FLOW WINDS ALONG THE UPPER YELLOWSTONE AND STILLWATER RIVER
VALLEYS. SHOULD ALSO SEE PERSISTENT DRAINAGE WINDS COMING OUT OF
THE MOUNTAINS IN CENTRAL MONTANA AND THE HIGH BASINS IN NORTHERN
WYOMING SO WILL SEE QUITE A CONTRAST BETWEEN PERSISTENT WINDS IN
THE RIVER VALLEYS VERSUS THE FLATTER PLAINS. RIDGE BEGINS TO BREAK
DOWN ON TUESDAY AND WHAT HAPPENS AT FURTHER OUT TIME FRAMES IS NOT
VERY CLEAR WITH MODELS HINTING AT AN ARCTIC MAYBE RETURNING TOWARDS
THE LATTER PART OF NEXT WEEK.
TEMPERATURES WILL BEGIN CLIMBING FROM THE 40S ON SATURDAY TO THE
50S EARLY NEXT WEEK. AS THE RIDGE BREAKS DOWN ON TUESDAY IT WILL
STILL BE MILD AND STRONGER DOWNSLOPE THAT DEVELOPS DURING THE
BREAKDOWN WILL BRING ADDITIONAL WARMING WHICH COULD CAUSE RECORD
HIGH TEMPERATURES TO BE APPROACHED. BORSUM
&&
.AVIATION...
STATIONARY FRONT HAS BEGUN TO SHIFT OVER WESTERN ZONES. BAND OF
LIGHT TO MODERATE SNOW WILL ALSO SHIFT WESTWARD. KBIL MAY SEE
PERIODS OF MODERATE SNOW WHICH WILL SIGNIFICANTLY DROP
VISIBILITIES AND CEILINGS. SNOW WILL ALSO CONTINUE ACROSS THE
BEARTOOTH AND BIG HORN MOUNTAINS WHERE MOUNTAIN PEAKS ARE LIKELY
OBSCURED. SNOW IS EXPECTED TO CONTINUE THROUGH THE OVERNIGHT
BEFORE TAPERING OFF THURSDAY MORNING. SCHUKNECHT/RICHMOND
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 008/040 035/052 036/050 032/052 036/056 036/044 030/042
+3/S 10/N 00/U 00/U 00/U 00/U 02/S
LVM 022/046 036/050 038/051 030/052 035/055 035/044 023/043
21/N 10/N 00/U 00/U 00/U 00/U 02/S
HDN 001/036 023/050 030/049 029/052 029/054 029/046 029/040
+4/S 10/U 00/U 00/U 00/U 00/U 02/S
MLS 908/026 014/049 025/043 022/048 027/052 027/041 023/033
75/S 20/U 20/U 00/U 00/U 00/U 02/S
4BQ 907/029 019/047 030/051 026/051 028/053 028/046 027/040
+5/S 20/U 20/U 00/U 00/U 00/U 02/S
BHK 918/013 010/041 019/040 020/046 023/052 023/040 022/031
23/S 30/U 21/U 00/U 00/U 00/U 02/S
SHR 016/037 024/049 030/050 025/052 026/054 026/047 027/041
+5/O 10/U 00/U 00/U 00/U 00/U 02/S
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONES 29-35-38-57.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 3 AM MST THURSDAY FOR
ZONES 30-31-36-58.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
000
FXUS65 KGGW 150241 AAA
AFDGGW
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
741 PM MST WED JAN 14 2009
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
GOING FORECAST IN DECENT SHAPE FOR THE SOUTHWESTERN TWO-THIRDS OF
THE CWA. BUT CLEAR SKIES HAVE ALLOWED TEMPS TO PLUMMET IN THE EAST.
HAD TO LOWER MIN TEMPS HERE AND ALSO LOWER CLOUDS.
WINDS ARE CURRENTLY 10-13 MPH FROM GLASGOW TO MALTA THIS EVENING.
MODELS SEEM TO BE A BIT WEAK WITH WINDS HERE AND MAY BE A BIT
STRONGER TONIGHT THAN PREVIOUS THINKING. THUS WIND CHILLS WILL
MEET ADVISORY LEVELS INTO THURSDAY MORNING (AND WILL ISSUE WC
ADVISORY WITH THIS PACKAGE). REST OF FORECAST IN GOOD SHAPE. JAMBA
PREVIOUS DISCUSSION...
HIGH PRESSURE SLOWLY SINKING SOUTHWARD ACROSS SASKATCHEWAN WITH
VERY COLD AIRMASS OVER EASTERN MONTANA. MOISTURE AND CHANNELED
VORTICITY IN THE NORTHWEST FLOW KEEPING LIGHT SNOW GOING ACROSS
CENTRAL MONTANA. WEST COAST UPPER RIDGE WILL SLOWLY PUSH
EAST...WITH THE HIGH PRESSURE DROPPING INTO THE DAKOTAS. THIS WILL
ALLOW THE FRONT THE LIFT BACK TO THE EAST AHEAD OF STRONG WARM AIR
ADVECTION. SOME POTENTIAL FOR OVERRUNNING PRECIPITATION THURSDAY
AND THURSDAY NIGHT WITH THE FRONT. THERMAL PROFILES SUGGEST THAT
MOST OF THE PRECIP WILL OCCUR AS SNOW...THE THE WARMER AIR ALSO
BEING DRIER. SMALL CHANCE OF FREEZING RAIN BUT ANY SHOULD BE VERY
BRIEF...JUST BEFORE THE PRECIP ENDS.
FRONT WILL BE INTO NORTH DAKOTA BY FRIDAY WITH STRONG DOWNSLOPE
DEVELOPING OVER NORTH CENTRAL MONTANA. THIS WILL RESULT IN WARMING
TEMPERATURES AND PERHAPS SOME BREEZY CONDITIONS ACROSS THE WESTERN
ZONES. EBERT
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
ONLY MINOR ADJUSTMENTS WERE MADE TO THE EXTENDED FORECAST AS HIGH
CONFIDENCE CONTINUES FOR A MILD DRY PERIOD WITH AN UPPER RIDGE MOVING
OVER WESTERN NORTH AMERICA THIS WEEKEND AND EARLY NEXT WEEK.
OPERATIONAL MODELS AND GFS ENSEMBLES CONTINUE TO TREND TOWARD A
PATTERN CHANGE FOR THE MIDDLE OF NEXT WEEK AS AN UPPER RIDGE
AMPLIFIES OVER THE EASTERN PACIFIC WHILE A TROUGH CARVES OUT OVER
THE INTERIOR OF NORTH AMERICA. 12Z GFS SOLUTION IS MUCH COLDER AND
FARTHER WEST WITH THE MEAN LONGWAVE TROUGH POSITION THAN THE 12Z
ECMWF...WHICH IS WARMER AND FARTHER EAST...AND MUCH DIFFERENT THAN
ITS 00Z SOLUTION. AJZ
PREVIOUS LONG TERM DISCUSSION...
THE EXPECTED MID-WINTER INTERLUDE OF SEVERAL DAYS OF DRY AND
MILDER WEATHER...CONTINUES ON TRACK. IN A CONTINUED VERY AMPLIFIED
PATTERN...THE STRONG UPPER HIGH WITH A CLOSED CENTER OVER OR/WA
SLOWLY MOVES E DURING MOST OF THE PERIOD... REACHING S MT. MODELS
REMAIN IN EXCELLENT AGREEMENT WITH THIS. THICKNESSES CLIMB TO 560
MB BY MON...WITH SOME 850 MODEL TEMPS AS HIGH AT 17C. AS ALMOST
ALWAYS IN JAN...ANYTHING EVEN CLOSE TO FULL WARMING POTENTIAL WILL
NOT OCCUR DUE TO ENERGY NEEDED TO MELT THE HEAVY SNOWPACK. LOW-
LEVEL ARE FROM A DOWNSLOPING W-NW COMPONENT...BUT NOT THAT STRONG
WITH SURFACE HIGH CENTER NEAR OUR AREA. CERTAINLY MOST OF THE AREA
S OF MISSOURI RIVER WHERE SNOWCOVER IS LESS...WILL GO TO BARE
GROUND ALLOWING TEMPS TO REACH THE 50S MON.
SOME MODELS HAVE SHOWN A WEAK SHORTWAVE MOVE THRU NE MT DIRECTLY
FORM THE N ABOUT SAT...BUT LOOKING VERY DRY AS IT GETS CAUGHT UP
AND TORN APART ANTI-CYCLONIC UPPER HIGH CIRCULATION. MODELS LOOK VERY
DRY DURING THE PERIOD EVEN IN LOWER LEVELS...SO SEVERAL DAYS OF
FULL SUNSHINE ALSO EXPECTED. EXPECT THERE COULD BE SOME PATCHY FOG
IN THE MORNING THOUGH...WITH SNOWMELT AND CLEAR SKIES...BUT FLOW
IS MORE OR LESS A DOWNSLOPING W FLOW IN THE LOWER LEVELS.
ALL MODELS ARE NOW INDICATING A CHANGE LATE IN THE PERIOD...WITH
THE UPPER HIGH FADING AWAY...WHILE ANOTHER HIGH BUILDS OVER THE
GULF OF AK. THIS WILL ALLOW AN ARCTIC COLD FRONT TO PUSH INTO NE
MT FOR COLDER WEATHER AND A THREAT OF SOME SNOW BY WED. SIMONSEN
&&
.AVIATION...
MOST...IF NOT ALL THE TAF SITES WILL HAVE CLEAR SKIES THIS
EVENING. A DECK OF MID LEVEL CLOUDS TO THE WEST WILL MOVE EAST AND
COVER THE TAF SITES BETWEEN 06Z AND 12Z. LOW CLOUDS WILL AFFECT
THE TAF SITES ON THURSDAY AS A WARM FRONT APPROACHES NORTHEAST
MONTANA. MVFR CEILINGS ARE POSSIBLE BUT LOW VFR CEILINGS ARE MORE
LIKELY. WINDS WILL BE LIGHT EXCEPT FOR 10 KNOTS EAST WINDS AT KGGW
OVERNIGHT. GFF
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 10 AM MST THURSDAY FOR CENTRAL AND
SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY.
&&
$$
WEATHER.GOV/GLASGOW
000
FXUS65 KTFX 142354
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
500 PM MST WED JAN 14 2009
.DISCUSSION...
TONIGHT THROUGH FRIDAY...BACK DOOR COLD FRONT REMAINS NEARLY
STATIONARY IN WESTERN PORTIONS OF NORTH CENTRAL MONTANA. EAST OF
THIS FEATURE TEMPERATURES REMAIN IN THE TEENS AND 20S...AND SINGLE
DIGITS IN THE FAR NORTHEAST...WITH 40S TO THE WEST OF THE FRONT.
LIGHT SNOW WILL CONTINUE TO FALL ACROSS MY EASTERN PLAINS THROUGH
THIS EVENING WITH PERHAPS ANOTHER INCH OR SO OF ACCUMULATION...SO
WILL CONTINUE THE WINTER WEATHER ADVISORY. OVERNIGHT TEMPERATURES
WILL REMAIN TRICKY AS MODELS SUGGEST THE FRONT COULD BEGIN TO DRIFT
EAST OVERNIGHT WITH TEMPERATURES RISING IN ITS WAKE. FRONT BEGINS
TO MOVE OUT FOR SURE ON THURSDAY WITH TEMPERATURES RISING A GOOD 20
DEGREES ACROSS ALL BUT FAR NORTHEAST PORTIONS OF MY CWA. MY FAR
EASTERN ZONES ARE ALSO EXPECTED TO CONTINUE TO HAVE A CHANCE OF
WARM ADVECTION PRECIPITATION TOMORROW AS THE FRONT LIFTS OUT OF
THE AREA. BY LATE THURSDAY NIGHT THE FRONT IS EXPECTED TO
COMPLETELY EXIT CENTRAL MONTANA WITH MY ENTIRE FORECAST AREA
COMING UNDER THE INFLUENCE OF A STRONG UPPER LEVEL RIDGE THAT WILL
PERSIST INTO THE WEEKEND. AM EXPECTING MOSTLY CLEAR SKIES WITH
TEMPERATURES RISING WELL ABOVE SEASONAL AVERAGES. MPJ
FRIDAY NIGHT THROUGH MONDAY NIGHT. ALL MODELS STILL ON TRACK IN
SHOWING ARRIVAL OF STRONG PACIFIC UPPER RIDGE OVER THE WESTERN US
DURING THIS PERIOD. LEADING EDGE OF THE RIDGE EXTENDS ALL THE WAY
INTO ERN MT BY FRIDAY NIGHT. AIRMASS ACROSS CENTRAL AND SOUTHWEST MT
WILL BECOME PROGRESSIVELY DRIER AND WARMER THROUGH THE WEEKEND. A
WEAK SHORTWAVE TROF COMES DOWN THE EAST SIDE OF THE RIDGE ON SAT BUT
SHOULD PRODUCE LITTLE MORE THAN SLIGHTLY INCREASED HIGH CLOUD COVER
OVER THE REGION. UPPER RIDGE AXIS WILL BE CENTERED ALONG THE
CONTINENTAL DIVIDE BY MONDAY AS RIDGE MAKE SLOW PROGRESSION TO THE
EAST. KEPT PREVIOUS SHIFTS DECISION TO GO SEVERAL DEGREES ABOVE
GUIDANCE FOR MAX TEMPS ON SAT AND SUN AS CLEAR TO SCATTERED SKIES
WILL PROVIDE EXTENDED PERIODS OF SUNSHINE. THIS WILL CAUSE RAPID
MELTING OF CURRENT SNOW COVER IN THE PLAINS ALLOWING LOW LEVEL TEMPS
TO WARM SIGNIFICANTLY...AS EVIDENCED BY MODEL FORECASTS OF TEMPS IN
LOW-MID 50S UP TO 850 MB/5000 FT ELEV ON SUN AFTN. WARANAUSKAS
TUESDAY AND WEDNESDAY...CURRENT MODELS DEPICT A HIGH PRESSURE RIDGE
OVER CENTRAL MONTANA WHICH WILL GIVE WAY TO A PACIFIC LOW PRESSURE
TROUGH EXPECTED TO MOVE INTO THE REGION BY THURSDAY AFTERNOON. A
CHANCE FOR PRECIPITATION FOR MUCH OF THE CWA THURSDAY AND THURSDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL AS THE FRONT
ADVANCES INTO THE REGION. SAUCIER
&&
.AVIATION...
UPDATED 0000Z.
OVERALL CONFIDENCE IN THE FORECAST IS LOW. FOR SOUTHWEST MONTANA
EXPECT VFR CONDITIONS THROUGH 07Z. AFTER THAT THERE IS THE POTENTIAL
FOR VALLEY FOG WITH CONDITIONS LOCALLY LIFR. FEEL THREAT OF FOG IS
LOW ENOUGH TO JUST MENTION VICINITY FOG IN THE TAFS FOR KBZN AND
KHLN. OVER THE PLAINS EXPECT WIDESPREAD CEILINGS IN THE LOW MVFR OR
IFR RANGE THROUGH MIDNIGHT. EXPECT WIDESPREAD IFR VISIBILITIES AT
KHVR THROUGH MUCH OF THE NIGHT IN SNOW. HOWEVER AT KLWT/KGTF/KCTB
COULD ALSO SEE IFR VISIBILITIES AND FEEL THERE IS ENOUGH OF A THREAT
THAT HAVE GONE WITH TEMPO GROUPS THROUGH MIDNIGHT. FOR LATE TONIGHT
INTO THURSDAY MORNING THERE IS A HUGE DIFFERENCE AMONGST GUIDANCE
WITH SOME GUIDANCE FORECASTING LIFR CEILINGS AND VISIBILITIES AND
OTHER GUIDANCE FORECASTING VFR CEILINGS AND VISIBILITIES. HAVE
TENDED TO LEAN TOWARDS THE FORMER FOR THE KHVR/KLWT TAFS AND THE
LATTER FOR THE KGTF/KCTB TAFS. HOWEVER WOULD NOT BE TOTALLY
SURPRISED TO SEE LIFR CEILINGS AND VISIBILITIES AT KCTB AND KGTF
INTO EARLY THURSDAY MORNING. DO FEEL PRETTY CONFIDENT THAT
KLWT/KGTF/KCTB WILL SEE VFR CONDITIONS BY NOON THURSDAY. EXPECT
WINDS TO STAY GENERALLY LESS THAN 15 KNOTS THROUGH THE PERIOD. BLANK
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 16 47 32 52 / 10 0 0 0
CTB 18 44 30 53 / 10 0 0 0
HLN 25 50 24 52 / 10 0 0 0
BZN 24 45 23 49 / 20 0 0 0
WEY 16 29 12 32 / 10 10 0 0
DLN 26 45 23 49 / 10 0 0 0
HVR -5 30 14 43 / 50 20 0 0
LWT 16 40 26 50 / 60 20 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR MTZ011-
013-047-050-051.
&&
$$
SHORT TERM...MPJ
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...COULSTON
WEATHER.GOV/GREATFALLS
000
FXUS65 KBYZ 142246
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
346 PM MST WED JAN 14 2009
.SHORT TERM...VALID FOR THU AND FRI...
NO CHANGES TO THE WINTER WEATHER ADVISORIES FOR THE AREA. HAVE
RECEIVED WIDESPREAD 2 TO 4 INCH SNOW ACCUMULATIONS THIS AFTERNOON
OVER THE ADVISORY AREA. BILLINGS WAS A NOTABLE EXCEPTION AS THE
SNOW BAND HAS SET UP JUST A FEW MILES TO THE EAST OF
TOWN...HOWEVER MUCH OF YELLOWSTONE COUNTY EAST OF HIGHWAY 87 HAS
SEEN SIGNIFICANT SNOWFALL TODAY.
FOR SNOW AMOUNTS TONIGHT...EXPECT 2 TO 4 ADDITIONAL INCHES WITH
THE MAIN SNOW BAND...AND LESS THAN AN INCH JUST OUTSIDE OF THE
BAND ON EITHER SIDE. LOCALLY HEAVIER AMOUNTS WILL BE POSSIBLE
WITHIN THE MAIN BAND...ESPECIALLY NEAR THE FOOTHILLS OF THE BIG
HORN MOUNTAINS.
A LOT OF ISSUES WITH THE MODELS TODAY AS THEY SIMPLY HAVE NOT
HANDLED THIS SHALLOW COLD AIR INTRUSION WELL AT ALL. WHILE THE
UPPER LEVEL PATTERN SEEMS REASONABLE THAT IS NOT TRANSLATING TO
THE LOWER LEVELS AS FORCING PATTERNS ARE ALL OVER THE PLACE AND
NONE SHOW ANY SIMILARITY TO THE PERSISTENT SNOW BAND ACROSS CENTRAL
SECTIONS TODAY. HAVE A GOOD IDEA OF THE MECHANISMS AND FORCING
RESPONSIBLE BUT TIMING THE COLD AIR MOVING OUT OF THE REGION WILL
BE TOUGH GIVEN UNRELIABLE DATA TODAY. AS A RESULT HAVE LEANED
TOWARD PERSISTENCE AND CURRENT CONDITIONS FOR TONIGHT INTO
TOMORROW. KEPT IDEA OF CATEGORICAL POPS GOING WITH THE SNOW BAND
TONIGHT. WARM ADVECTION SHOULD PICK UP LATE TONIGHT AND BEGIN TO
SLOWLY PUSH PRECIPITATION EASTWARD BY MORNING. THIS WILL BE A SLOW
PROCESS HOWEVER GIVEN THAT NO STRONG LEE SIDE CYCLOGENESIS IS
EXPECTED THUS WINDS WILL BE LIGHT TO MODERATE THROUGH THE WARMING
PROCESS. THIS WILL ALSO ALLOW FOR GOOD ISENTROPIC UPGLIDE TO
LINGER OVER A BROADER AREA THROUGH THURSDAY INTO THURSDAY EVENING BEFORE
FINALLY SHIFTING OUT OF THE AREA. THIS TYPE OF SLOWER CHANGE WILL
ALSO MEAN THAT HIGHER ELEVATION LOCATIONS IN THE VICINITY OF THE
WARM FRONT WILL BE MUCH WARMER THAN SURROUNDING LOWER ELEVATION
LOCATIONS FOR POSSIBLY A LONG DURATION...PARTICULARLY IN THE MAJOR
RIVER VALLEYS. A GOOD EXAMPLE WILL BE THE AIRPORT IN BILLINGS
COMPARED TO DOWNTOWN WHERE A 15 TO 20 DEGREE DIFFERENCE FOR
SEVERAL HOURS IS NOT OUT OF THE QUESTION AS THE WARM FRONT PASSES
TOMORROW MORNING.
EXPECT TEMPERATURES TO MAKE IT INTO THE UPPER 40S WEST
TOMORROW...TRENDING TO THE TEENS IN FAR EASTERN LOCATIONS.
WARMING WILL LIKELY CONTINUE THROUGH THURSDAY NIGHT AS WARMER AIR
CONTINUES TO BUILD IN FROM THE WEST WITH A STRONG UPPER RIDGE
TAKING SHAPE. HIGHS FRIDAY AND SATURDAY WILL CONTINUE TO WARM
INTO THE 50S WEST AND CENTRAL...WITH 40S EAST. DRY CONDITIONS
WILL PREVAIL ACROSS THE AREA FROM THURSDAY EVENING INTO THE
WEEKEND.
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
SATURDAY THROUGH MONDAY WILL SEE A HIGH AMPLITUDE RIDGE MOVE
ACROSS THE PACIFIC NORTHWEST INTO CENTRAL MONTANA BRINGING A
MILD...DRY WEATHER PATTERN TO THE AREA. STRONG INVERSIONS OVER
YELLOWSTONE PARK AND SOUTHEAST IDAHO SHOULD SUPPORT EPISODES OF
GAP FLOW WINDS ALONG THE UPPER YELLOWSTONE AND STILLWATER RIVER
VALLEYS. SHOULD ALSO SEE PERSISTENT DRAINAGE WINDS COMING OUT OF
THE MOUNTAINS IN CENTRAL MONTANA AND THE HIGH BASINS IN NORTHERN
WYOMING SO WILL SEE QUITE A CONTRAST BETWEEN PERSISTENT WINDS IN
THE RIVER VALLEYS VERSUS THE FLATTER PLAINS. RIDGE BEGINS TO BREAK
DOWN ON TUESDAY AND WHAT HAPPENS AT FURTHER OUT TIME FRAMES IS NOT
VERY CLEAR WITH MODELS HINTING AT AN ARCTIC MAYBE RETURNING TOWARDS
THE LATTER PART OF NEXT WEEK.
TEMPERATURES WILL BEGIN CLIMBING FROM THE 40S ON SATURDAY TO THE
50S EARLY NEXT WEEK. AS THE RIDGE BREAKS DOWN ON TUESDAY IT WILL
STILL BE MILD AND STRONGER DOWNSLOPE THAT DEVELOPS DURING THE
BREAKDOWN WILL BRING ADDITIONAL WARMING WHICH COULD CAUSE RECORD
HIGH TEMPERATURES TO BE APPROACHED. BORSUM
&&
.AVIATION...
A STATIONARY ARCTIC FRONT 80 TO 100 MILES WEST OF KBIL WILL CAUSE
A STRIP OF IFR TO LIFR CONDITIONS 100 MILES EAST AND 30 MILES WEST
OF A LINE FROM KLWT TO KBIL TO KSHR DUE TO SNOW AND CEILINGS. EAST
AND WEST OF THIS AREA MOSTLY VFR CONDITIONS ARE EXPECTED THOUGH
ISOLATED SNOW SHOWERS MAY CREATE BRIEF MVFR CONDITIONS. LITTLE
CHANGE IS EXPECTED IN THIS PATTERN UNTIL THURSDAY MORNING. BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 013/040 035/052 036/050 032/052 036/056 036/044 030/042
+3/S 10/N 00/U 00/U 00/U 00/U 02/S
LVM 022/046 036/050 038/051 030/052 035/055 035/044 023/043
21/N 10/N 00/U 00/U 00/U 00/U 02/S
HDN 006/036 023/050 030/049 029/052 029/054 029/046 029/040
+4/S 10/U 00/U 00/U 00/U 00/U 02/S
MLS 905/026 014/049 025/043 022/048 027/052 027/041 023/033
75/S 20/U 20/U 00/U 00/U 00/U 02/S
4BQ 904/029 019/047 030/051 026/051 028/053 028/046 027/040
+5/S 20/U 20/U 00/U 00/U 00/U 02/S
BHK 915/013 010/041 019/040 020/046 023/052 023/040 022/031
23/S 30/U 21/U 00/U 00/U 00/U 02/S
SHR 016/037 024/049 030/050 025/052 026/054 026/047 027/041
+5/O 10/U 00/U 00/U 00/U 00/U 02/S
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONES 29-35-38-57.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 3 AM MST THURSDAY FOR
ZONES 30-31-36-58.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
000
FXUS65 KGGW 142221
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
321 PM MST WED JAN 14 2009
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
HIGH PRESSURE SLOWLY SINKING SOUTHWARD ACROSS SASKATCHEWAN WITH
VERY COLD AIRMASS OVER EASTERN MONTANA. MOISTURE AND CHANNELED
VORTICITY IN THE NORTHWEST FLOW KEEPING LIGHT SNOW GOING ACROSS
CENTRAL MONTANA. WEST COAST UPPER RIDGE WILL SLOWLY PUSH
EAST...WITH THE HIGH PRESSURE DROPPING INTO THE DAKOTAS. THIS WILL
ALLOW THE FRONT THE LIFT BACK TO THE EAST AHEAD OF STRONG WARM AIR
ADVECTION. SOME POTENTIAL FOR OVERRUNNING PRECIPITATION THURSDAY
AND THURSDAY NIGHT WITH THE FRONT. THERMAL PROFILES SUGGEST THAT
MOST OF THE PRECIP WILL OCCUR AS SNOW...THE THE WARMER AIR ALSO
BEING DRIER. SMALL CHANCE OF FREEZING RAIN BUT ANY SHOULD BE VERY
BRIEF...JUST BEFORE THE PRECIP ENDS.
FRONT WILL BE INTO NORTH DAKOTA BY FRIDAY WITH STRONG DOWNSLOPE
DEVELOPING OVER NORTH CENTRAL MONTANA. THIS WILL RESULT IN WARMING
TEMPERATURES AND PERHAPS SOME BREEZY CONDITIONS ACROSS THE WESTERN
ZONES. EBERT
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
ONLY MINOR ADJUSTMENTS WERE MADE TO THE EXTENDED FORECAST AS HIGH
CONFIDENCE CONTINUES FOR A MILD DRY PERIOD WITH AN UPPER RIDGE MOVING
OVER WESTERN NORTH AMERICA THIS WEEKEND AND EARLY NEXT WEEK.
OPERATIONAL MODELS AND GFS ENSEMBLES CONTINUE TO TREND TOWARD A
PATTERN CHANGE FOR THE MIDDLE OF NEXT WEEK AS AN UPPER RIDGE
AMPLIFIES OVER THE EASTERN PACIFIC WHILE A TROUGH CARVES OUT OVER
THE INTERIOR OF NORTH AMERICA. 12Z GFS SOLUTION IS MUCH COLDER AND
FARTHER WEST WITH THE MEAN LONGWAVE TROUGH POSITION THAN THE 12Z
ECMWF...WHICH IS WARMER AND FARTHER EAST...AND MUCH DIFFERENT THAN
ITS 00Z SOLUTION. AJZ
PREVIOUS LONG TERM DISCUSSION...
THE EXPECTED MID-WINTER INTERLUDE OF SEVERAL DAYS OF DRY AND
MILDER WEATHER...CONTINUES ON TRACK. IN A CONTINUED VERY AMPLIFIED
PATTERN...THE STRONG UPPER HIGH WITH A CLOSED CENTER OVER OR/WA
SLOWLY MOVES E DURING MOST OF THE PERIOD... REACHING S MT. MODELS
REMAIN IN EXCELLENT AGREEMENT WITH THIS. THICKNESSES CLIMB TO 560
MB BY MON...WITH SOME 850 MODEL TEMPS AS HIGH AT 17C. AS ALMOST
ALWAYS IN JAN...ANYTHING EVEN CLOSE TO FULL WARMING POTENTIAL WILL
NOT OCCUR DUE TO ENERGY NEEDED TO MELT THE HEAVY SNOWPACK. LOW-
LEVEL ARE FROM A DOWNSLOPING W-NW COMPONENT...BUT NOT THAT STRONG
WITH SURFACE HIGH CENTER NEAR OUR AREA. CERTAINLY MOST OF THE AREA
S OF MISSOURI RIVER WHERE SNOWCOVER IS LESS...WILL GO TO BARE
GROUND ALLOWING TEMPS TO REACH THE 50S MON.
SOME MODELS HAVE SHOWN A WEAK SHORTWAVE MOVE THRU NE MT DIRECTLY
FORM THE N ABOUT SAT...BUT LOOKING VERY DRY AS IT GETS CAUGHT UP
AND TORN APART ANTI-CYCLONIC UPPER HIGH CIRCULATION. MODELS LOOK VERY
DRY DURING THE PERIOD EVEN IN LOWER LEVELS...SO SEVERAL DAYS OF
FULL SUNSHINE ALSO EXPECTED. EXPECT THERE COULD BE SOME PATCHY FOG
IN THE MORNING THOUGH...WITH SNOWMELT AND CLEAR SKIES...BUT FLOW
IS MORE OR LESS A DOWNSLOPING W FLOW IN THE LOWER LEVELS.
ALL MODELS ARE NOW INDICATING A CHANGE LATE IN THE PERIOD...WITH
THE UPPER HIGH FADING AWAY...WHILE ANOTHER HIGH BUILDS OVER THE
GULF OF AK. THIS WILL ALLOW AN ARCTIC COLD FRONT TO PUSH INTO NE
MT FOR COLDER WEATHER AND A THREAT OF SOME SNOW BY WED. SIMONSEN
&&
.AVIATION...
VFR. A PERSISTENT BROKEN DECK WILL CONTINUE THROUGH THURSDAY
EVENING AT ALL OF THE TAF SITES. WINDS WILL BE LIGHT AND OUT OF THE
EAST AT 8 TO 10 KNOTS. SHALLENBERGER
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
000
FXUS65 KMSO 142150
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
250 PM MST WED JAN 14 2009
...INCREASING FOG AND AIR QUALITY CONCERNS ARE LIKELY FROM
THURSDAY NIGHT THROUGH MONDAY...
.DISCUSSION...
TONIGHT THROUGH FRIDAY...THE NORTHERN ROCKIES REGION WILL CONTINUE
TO BE UNDER A NORTHWESTERLY FLOW ALOFT THROUGH THE END OF THE WEEK
AS HIGH PRESSURE CONTINUES ON THE WEST COAST. MOISTURE CONTINUES
TO PASS OVER THE APEX OF THE RIDGE ALLOWING FOR CLOUD COVER TO
PASS OVER NORTHERN IDAHO AND WESTERN MONTANA. FOR THE MOST PART
THE CLOUDS HAVE BEEN EITHER HIGH ENOUGH OR THERE HAVE BEEN ENOUGH
CLEAR PERIODS THAT NORTHWEST MONTANA HAS BEEN EXPERIENCING FOG.
CENTRAL IDAHO HAS NOT SEEN AS MUCH CLOUD COVER AS WESTERN MONTANA
AND HAS HAD MORE WIDESPREAD FOG DEVELOPMENT. THE HIGH PRESSURE
RIDGE WILL SLOWLY MOVE EASTWARD ALLOWING FOR STRENGTHENING
INVERSIONS AND INCREASING FOG COVERAGE. SKY COVER WILL PUT A
DAMPER ON THE FULL INVERSION POTENTIAL...BUT CONDITIONS CONTINUE
TO LOOK FAVORABLE FOR INCREASED FOG COVERAGE...ESPECIALLY IN IDAHO
AND NORTHWEST MONTANA.
SATURDAY THROUGH TUESDAY...STRONG RIDGE WILL CONTINUE TO MAINTAIN
ITS GRIP ACROSS THE WESTERN U.S. THE RIDGE AXIS WILL MOVE OVER THE
NORTHERN ROCKIES. STRONG INVERSIONS UNDER THIS RIDGE AXIS WILL
ENHANCE WIDESPREAD FREEZING FOG IN THE VALLEYS. THE FOG HAS THE
POTENTIAL TO BE A FEW THOUSAND FEET THICK AND APPROACH THE RIDGE TOPS
DURING THE COURSE OF THE ENTIRE DAY AND NIGHT.
WEDNESDAY...MODELS ARE INDICATING A SUBTLE CHANGE BY INTRODUCING A
WEAK TROF ALONG THE WEST COAST WHICH WILL PUSH THE RIDGE TO THE
EAST. A FEW SHOWERS MAY BE POSSIBLE IN NORTHWEST MONTANA.
&&
.AVIATION...NORTHWESTERLY FLOW ALOFT WILL CONTINUE THROUGH THE END
OF THE WEEK. CLOUDS WILL PASS THROUGH THE AREA...BUT THE MAIN
IMPACT WILL BE FOG DEVELOPMENT. NORTH CENTRAL IDAHO AND NORTHWEST
MONTANA WILL BE THE MOST AFFECTED BY THIS FOG THROUGH THE NEXT 24
HOURS. KGPI WILL BEGIN TO SEE FOG DEVELOP AFTER MIDNIGHT...BUT NOT
EXPECTED VISIBILITY RESTRICTIONS UNTIL AROUND 11Z. FOG WILL BE
SLOW TO DISSIPATE WITH VCFG POSSIBLE THROUGH THE DAY. KMSO WILL
REACH SATURATION DURING THE EARLY MORNING WITH PATCHY FOG AND
BRIEF PERIODS OF REDUCED VISIBILITIES POSSIBLE BEFORE 17Z. FOG
WILL BECOME MORE WIDESPREAD FOR FRIDAY AND THE WEEKEND WITH
AVIATION IMPACTS LIKELY.
&&
.AIR STAGNATION...IDAHO...AIR QUALITY IS EXPECTED TO DETERIORATE
THURSDAY THROUGH MONDAY ACROSS CENTRAL IDAHO AS POLLUTANTS BECOME
TRAPPED IN THE VALLEYS UNDER DEVELOPING STRONG INVERSIONS.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&
$$
SHORT TERM...KITSMILLER
LONG TERM....RPN
AVIATION...KITSMILLER
000
FXUS65 KTFX 142138
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
238 PM MST WED JAN 14 2009
.DISCUSSION...
TONIGHT THROUGH FRIDAY...BACK DOOR COLD FRONT REMAINS NEARLY
STATIONARY IN WESTERN PORTIONS OF NORTH CENTRAL MONTANA. EAST OF
THIS FEATURE TEMPERATURES REMAIN IN THE TEENS AND 20S...AND SINGLE
DIGITS IN THE FAR NORTHEAST...WITH 40S TO THE WEST OF THE FRONT.
LIGHT SNOW WILL CONTINUE TO FALL ACROSS MY EASTERN PLAINS THROUGH
THIS EVENING WITH PERHAPS ANOTHER INCH OR SO OF ACCUMULATION...SO
WILL CONTINUE THE WINTER WEATHER ADVISORY. OVERNIGHT TEMPERATURES
WILL REMAIN TRICKY AS MODELS SUGGEST THE FRONT COULD BEGIN TO DRIFT
EAST OVERNIGHT WITH TEMPERATURES RISING IN ITS WAKE. FRONT BEGINS
TO MOVE OUT FOR SURE ON THURSDAY WITH TEMPERATURES RISING A GOOD 20
DEGREES ACROSS ALL BUT FAR NORTHEAST PORTIONS OF MY CWA. MY FAR
EASTERN ZONES ARE ALSO EXPECTED TO CONTINUE TO HAVE A CHANCE OF
WARM ADVECTION PRECIPITATION TOMORROW AS THE FRONT LIFTS OUT OF
THE AREA. BY LATE THURSDAY NIGHT THE FRONT IS EXPECTED TO
COMPLETELY EXIT CENTRAL MONTANA WITH MY ENTIRE FORECAST AREA
COMING UNDER THE INFLUENCE OF A STRONG UPPER LEVEL RIDGE THAT WILL
PERSIST INTO THE WEEKEND. AM EXPECTING MOSTLY CLEAR SKIES WITH
TEMPERATURES RISING WELL ABOVE SEASONAL AVERAGES. MPJ
FRIDAY NIGHT THROUGH MONDAY NIGHT. ALL MODELS STILL ON TRACK IN
SHOWING ARRIVAL OF STRONG PACIFIC UPPER RIDGE OVER THE WESTERN US
DURING THIS PERIOD. LEADING EDGE OF THE RIDGE EXTENDS ALL THE WAY
INTO ERN MT BY FRIDAY NIGHT. AIRMASS ACROSS CENTRAL AND SOUTHWEST MT
WILL BECOME PROGRESSIVELY DRIER AND WARMER THROUGH THE WEEKEND. A
WEAK SHORTWAVE TROF COMES DOWN THE EAST SIDE OF THE RIDGE ON SAT BUT
SHOULD PRODUCE LITTLE MORE THAN SLIGHTLY INCREASED HIGH CLOUD COVER
OVER THE REGION. UPPER RIDGE AXIS WILL BE CENTERED ALONG THE
CONTINENTAL DIVIDE BY MONDAY AS RIDGE MAKE SLOW PROGRESSION TO THE
EAST. KEPT PREVIOUS SHIFTS DECISION TO GO SEVERAL DEGREES ABOVE
GUIDANCE FOR MAX TEMPS ON SAT AND SUN AS CLEAR TO SCATTERED SKIES
WILL PROVIDE EXTENDED PERIODS OF SUNSHINE. THIS WILL CAUSE RAPID
MELTING OF CURRENT SNOW COVER IN THE PLAINS ALLOWING LOW LEVEL TEMPS
TO WARM SIGNIFICANTLY...AS EVIDENCED BY MODEL FORECASTS OF TEMPS IN
LOW-MID 50S UP TO 850 MB/5000 FT ELEV ON SUN AFTN. WARANAUSKAS
TUESDAY AND WEDNESDAY...CURRENT MODELS DEPICT A HIGH PRESSURE RIDGE
OVER CENTRAL MONTANA WHICH WILL GIVE WAY TO A PACIFIC LOW PRESSURE
TROUGH EXPECTED TO MOVE INTO THE REGION BY THURSDAY AFTERNOON. A
CHANCE FOR PRECIPITATION FOR MUCH OF THE CWA THURSDAY AND THURSDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL AS THE FRONT
ADVANCES INTO THE REGION. SAUCIER
&&
.AVIATION...
UPDATED 1800Z.
THE MOIST NORTHWEST FLOW ALOFT WILL KEEP NORTH CENTRAL...CENTRAL...
AND SOUTHWEST MONTANA MOSTLY CLOUDY INTO AT LEAST EARLY THIS
EVENING. CONDITIONS WILL MOSTLY BE VFR ACROSS SOUTHWEST MONTANA
(KHLN AND KBZN TERMINALS) WITH MID LEVEL CLOUDINESS AND MAINLY
MOUNTAIN SNOW AND RAIN SHOWERS OBSCURING MOUNTAIN TOPS. HOWEVER...A
LOW LEVEL EASTERLY UPSLOPE FLOW WILL KEEP LOWER CLOUDS WITH
AREAS OF SNOW AND MOUNTAIN OBSCURATION ACROSS NORTH CENTRAL AND
CENTRAL MONTANA. THE HEAVIER SNOW WILL REMAIN EAST OF A KCTB-TO-KGTF
LINE...BUT WIDESPREAD MVFR TO IFR CONDITIONS WILL PERSIST OVER THE
ENTIRE AREA (INCLUDING KGTF KCTB KLWT KHVR TERMINALS). SNOW WILL
DECREASE AND CONDITIONS WILL GRADUALLY IMPROVE FROM THE WEST
OVERNIGHT AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA AND FORCES
THE MOISTURE EAST OF THE AREA. WINDS WILL REMAIN LIGHT THROUGH THE
PERIOD. COULSTON
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 16 47 32 52 / 10 0 0 0
CTB 18 44 30 53 / 10 0 0 0
HLN 25 50 24 52 / 10 0 0 0
BZN 24 45 23 49 / 20 0 0 0
WEY 16 29 12 32 / 10 10 0 0
DLN 26 45 23 49 / 10 0 0 0
HVR -5 30 14 43 / 50 20 0 0
LWT 16 40 26 50 / 60 20 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR MTZ011-
013-047-050-051.
&&
$$
SHORT TERM...MPJ
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...COULSTON
WEATHER.GOV/GREATFALLS
000
FXUS65 KTFX 141801
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1100 AM MST WED JAN 14 2009
...UPDATE TO AVIATION...
.UPDATE...BACKDOOR COLD FRONT CONTINUES TO DRIFT SLOWLY SOUTHWEST
THROUGH CENTRAL MONTANA THIS MORNING. VERY COLD TEMPERATURES
WILL KEEP MY NORTHEAST ZONES VERY COLD WHILE FAR SOUTHWEST MONTANA
IS EXPECTED TO REMAIN WELL ABOVE FREEZING. HAVE UPDATED
TEMPERATURE FORECAST TO REFLECT COLDER TEMPERATURES IN THE
NORTHEAST AND WARMER IN THE SOUTHWEST. ALSO MADE A FEW HAIL MARY
TWEAKS IN CENTRAL ZONES WHERE I EXPECT TEMPERATURES TO REMAIN
NEARLY STATIONARY OR TO SLOWLY FALL THROUGH MUCH OF THE DAY...
ALTHOUGH MODELS ARE SHOWING THAT THE FRONT SHOULD SLOSH BACK TO
THE EAST AND TEMPERATURES COULD RISE BACK UP AGAIN. HAVE ALSO
TWEAKED WINDS TO REFLECT EASTERLY WINDS ACROSS CENTRAL PORTIONS OF
THE CWA WHERE THE FRONT HAS MOVED THROUGH...AND ADDED AREAS OF
FREEZING FOG ALONG THE FRONTAL BOUNDARY. FINALLY MADE SOME MINOR
TWEAKS TO POPS AND PRECIPITATION TYPES TO REFLECT COLDER
TEMPERATURES. MPJ
&&
.AVIATION...
UPDATED 1800Z.
THE MOIST NORTHWEST FLOW ALOFT WILL KEEP NORTH CENTRAL...CENTRAL...
AND SOUTHWEST MONTANA MOSTLY CLOUDY INTO AT LEAST EARLY THIS
EVENING. CONDITIONS WILL MOSTLY BE VFR ACROSS SOUTHWEST MONTANA
(KHLN AND KBZN TERMINALS) WITH MID LEVEL CLOUDINESS AND MAINLY
MOUNTAIN SNOW AND RAIN SHOWERS OBSCURING MOUNTAIN TOPS. HOWEVER...A
LOW LEVEL EASTERLY UPSLOPE FLOW WILL KEEP LOWER CLOUDS WITH
AREAS OF SNOW AND MOUNTAIN OBSCURATION ACROSS NORTH CENTRAL AND
CENTRAL MONTANA. THE HEAVIER SNOW WILL REMAIN EAST OF A KCTB-TO-KGTF
LINE...BUT WIDESPREAD MVFR TO IFR CONDITIONS WILL PERSIST OVER THE
ENTIRE AREA (INCLUDING KGTF KCTB KLWT KHVR TERMINALS). SNOW WILL
DECREASE AND CONDITIONS WILL GRADUALLY IMPROVE FROM THE WEST
OVERNIGHT AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA AND FORCES
THE MOISTURE EAST OF THE AREA. WINDS WILL REMAIN LIGHT THROUGH THE
PERIOD. COULSTON
&&
.PREV DISCUSSION...
/ISSUED 440 AM MST WED JAN 14 2009/
WEDNESDAY THROUGH FRIDAY...PRECIP IS CURRENTLY FALLING OVER THE
EASTER PART OF THE CWA IN ASSOCIATION WITH THE THE COLD FRONT THAT
IS MOVING THROUGH THE AREA. EXPECTING TO SEE SCATTERED SNOW
SHOWERS THROUGH THE REST OF THE DAY ESPECIALLY OVER FERGUS AND
BLAINE COUNTIES. ACCUMULATIONS FROM THIS SYSTEM SHOULD REMAIN
BELOW WARNING CRITERIA AND HAVE STUCK WITH AN ADVISORY AT THIS
POINT. NOT ANTICIPATING AN UPGRADE WITH THIS SYSTEM...BUT WILL
CONTINUE TO MONITOR IN CASE SOME INCREASED INSTABILITY BEGINS TO
CAUSE BANDING. OTHERWISE A RELATIVELY CALM SITUATION FOR THE REST
OF THE PERIOD AS A UPPER LEVEL RIDGE OF HIGH PRESSURE BEGINS TO
BUILD AND EXERT ITS INFLUENCE. TEMPERATURES SHOULD WARM
DRAMATICALLY AS THE UPPER LEVEL MOISTURE IS CUT OFF AND THE SKIES
BEGIN TO CLEAR FOR NEXT COUPLE OF DAYS.
FRIDAY NIGHT THROUGH MONDAY NIGHT. ALL MODELS STILL ON TRACK IN
SHOWING ARRIVAL OF STRONG PACIFIC UPPER RIDGE OVER THE WESTERN US
DURING THIS PERIOD. LEADING EDGE OF THE RIDGE EXTENDS ALL THE WAY
INTO ERN MT BY FRIDAY NIGHT. AIRMASS ACROSS CENTRAL AND SOUTHWEST MT
WILL BECOME PROGRESSIVELY DRIER AND WARMER THROUGH THE WEEKEND. A
WEAK SHORTWAVE TROF COMES DOWN THE EAST SIDE OF THE RIDGE ON SAT BUT
SHOULD PRODUCE LITTLE MORE THAN SLIGHTLY INCREASED HIGH CLOUD COVER
OVER THE REGION. UPPER RIDGE AXIS WILL BE CENTERED ALONG THE
CONTINENTAL DIVIDE BY MONDAY AS RIDGE MAKE SLOW PROGRESSION TO THE
EAST. KEPT PREVIOUS SHIFTS DECISION TO GO SEVERAL DEGREES ABOVE
GUIDANCE FOR MAX TEMPS ON SAT AND SUN AS CLEAR TO SCATTERED SKIES
WILL PROVIDE EXTENDED PERIODS OF SUNSHINE. THIS WILL CAUSE RAPID
MELTING OF CURRENT SNOW COVER IN THE PLAINS ALLOWING LOW LEVEL TEMPS
TO WARM SIGNIFICANTLY...AS EVIDENCED BY MODEL FORECASTS OF TEMPS IN
LOW-MID 50S UP TO 850 MB/5000 FT ELEV ON SUN AFTN. WARANAUSKAS
TUESDAY AND WEDNESDAY...CURRENT MODELS DEPICT A HIGH PRESSURE RIDGE
OVER CENTRAL MONTANA WHICH WILL GIVE WAY TO A PACIFIC LOW PRESSURE
TROUGH EXPECTED TO MOVE INTO THE REGION BY THURSDAY AFTERNOON. A
CHANCE FOR PRECIPITATION FOR MUCH OF THE CWA THURSDAY AND THURSDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL AS THE FRONT
ADVANCES INTO THE REGION. SAUCIER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 27 23 45 34 / 30 20 0 0
CTB 25 23 44 33 / 40 20 0 0
HLN 36 24 44 27 / 20 10 0 0
BZN 41 20 43 22 / 30 20 0 0
WEY 31 12 32 10 / 30 20 10 0
DLN 41 19 41 20 / 10 10 0 0
HVR 8 5 33 16 / 80 50 10 0
LWT 27 18 41 28 / 100 60 10 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR MTZ011-
013-047-050-051.
&&
$$
SHORT TERM...MPJ
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...COULSTON
WEATHER.GOV/GREATFALLS
000
FXUS65 KTFX 141707
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1007 AM MST WED JAN 14 2009
.UPDATE...BACKDOOR COLD FRONT CONTINUES TO DRIFT SLOWLY SOUTHWEST
THROUGH CENTRAL MONTANA THIS MORNING. VERY COLD TEMPERATURES
WILL KEEP MY NORTHEAST ZONES VERY COLD WHILE FAR SOUTHWEST MONTANA
IS EXPECTED TO REMAIN WELL ABOVE FREEZING. HAVE UPDATED
TEMPERATURE FORECAST TO REFLECT COLDER TEMPERATURES IN THE
NORTHEAST AND WARMER IN THE SOUTHWEST. ALSO MADE A FEW HAIL MARY
TWEAKS IN CENTRAL ZONES WHERE I EXPECT TEMPERATURES TO REMAIN
NEARLY STATIONARY OR TO SLOWLY FALL THROUGH MUCH OF THE DAY...
ALTHOUGH MODELS ARE SHOWING THAT THE FRONT SHOULD SLOSH BACK TO
THE EAST AND TEMPERATURES COULD RISE BACK UP AGAIN. HAVE ALSO
TWEAKED WINDS TO REFLECT EASTERLY WINDS ACROSS CENTRAL PORTIONS OF
THE CWA WHERE THE FRONT HAS MOVED THROUGH...AND ADDED AREAS OF
FREEZING FOG ALONG THE FRONTAL BOUNDARY. FINALLY MADE SOME MINOR
TWEAKS TO POPS AND PRECIPITATION TYPES TO REFLECT COLDER
TEMPERATURES. MPJ
&&
.AVIATION...
UPDATED 14/1140Z.
PERSISTENT MOIST NORTHWEST FLOW ALOFT WILL KEEP BROAD AREA OF LOW-
AND MID-LEVEL CLOUDS OVER CENTRAL AND SOUTHWEST MT TODAY. A SURFACE
FRONTAL BOUNDARY OVER NORTH CENTRAL MONTANA CONTINUES TO SLOWLY
DRIFT TO THE WEST-SOUTHWEST WITH LIGHT SNOW ALONG AND WEST OF THE
FRONT. THE FRONT SHOULD BECOME NEARLY STATIONARY THIS AFTN ALONG A
KCTB-TO-KBIL LINE AND ADDITIONAL MOISTURE DROPPING SOUTH OUT OF
CANADA WILL GENERATE AREAS OF LIGHT SNOW ACROSS CENTRAL MT. BEST
CHANCE OF ACCUMULATING SNOW FROM KHVR TO KLWT AS THEY WILL BE ON THE
COLD AIR SIDE OF THE FRONT. CEILINGS WILL BE A MIX OF VFR AND MVFR
FOR MUCH OF THE DAY...WITH IFR CONDITIONS POSSIBLE NEAR
PRECIPITATION AREAS. THE FRONTAL SYSTEM SHOULD SLIDE EASTWARD
TONIGHT AS STRONG HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE
PACIFIC ON THURS...GRADUALLY ENDING THE SNOW AND RAISING CEILINGS
TO VFR FROM WEST TO EAST. WARANAUSKAS
&&
.PREV DISCUSSION...
/ISSUED 440 AM MST WED JAN 14 2009/
WEDNESDAY THROUGH FRIDAY...PRECIP IS CURRENTLY FALLING OVER THE
EASTER PART OF THE CWA IN ASSOCIATION WITH THE THE COLD FRONT THAT
IS MOVING THROUGH THE AREA. EXPECTING TO SEE SCATTERED SNOW
SHOWERS THROUGH THE REST OF THE DAY ESPECIALLY OVER FERGUS AND
BLAINE COUNTIES. ACCUMULATIONS FROM THIS SYSTEM SHOULD REMAIN
BELOW WARNING CRITERIA AND HAVE STUCK WITH AN ADVISORY AT THIS
POINT. NOT ANTICIPATING AN UPGRADE WITH THIS SYSTEM...BUT WILL
CONTINUE TO MONITOR IN CASE SOME INCREASED INSTABILITY BEGINS TO
CAUSE BANDING. OTHERWISE A RELATIVELY CALM SITUATION FOR THE REST
OF THE PERIOD AS A UPPER LEVEL RIDGE OF HIGH PRESSURE BEGINS TO
BUILD AND EXERT ITS INFLUENCE. TEMPERATURES SHOULD WARM
DRAMATICALLY AS THE UPPER LEVEL MOISTURE IS CUT OFF AND THE SKIES
BEGIN TO CLEAR FOR NEXT COUPLE OF DAYS.
FRIDAY NIGHT THROUGH MONDAY NIGHT. ALL MODELS STILL ON TRACK IN
SHOWING ARRIVAL OF STRONG PACIFIC UPPER RIDGE OVER THE WESTERN US
DURING THIS PERIOD. LEADING EDGE OF THE RIDGE EXTENDS ALL THE WAY
INTO ERN MT BY FRIDAY NIGHT. AIRMASS ACROSS CENTRAL AND SOUTHWEST MT
WILL BECOME PROGRESSIVELY DRIER AND WARMER THROUGH THE WEEKEND. A
WEAK SHORTWAVE TROF COMES DOWN THE EAST SIDE OF THE RIDGE ON SAT BUT
SHOULD PRODUCE LITTLE MORE THAN SLIGHTLY INCREASED HIGH CLOUD COVER
OVER THE REGION. UPPER RIDGE AXIS WILL BE CENTERED ALONG THE
CONTINENTAL DIVIDE BY MONDAY AS RIDGE MAKE SLOW PROGRESSION TO THE
EAST. KEPT PREVIOUS SHIFTS DECISION TO GO SEVERAL DEGREES ABOVE
GUIDANCE FOR MAX TEMPS ON SAT AND SUN AS CLEAR TO SCATTERED SKIES
WILL PROVIDE EXTENDED PERIODS OF SUNSHINE. THIS WILL CAUSE RAPID
MELTING OF CURRENT SNOW COVER IN THE PLAINS ALLOWING LOW LEVEL TEMPS
TO WARM SIGNIFICANTLY...AS EVIDENCED BY MODEL FORECASTS OF TEMPS IN
LOW-MID 50S UP TO 850 MB/5000 FT ELEV ON SUN AFTN. WARANAUSKAS
TUESDAY AND WEDNESDAY...CURRENT MODELS DEPICT A HIGH PRESSURE RIDGE
OVER CENTRAL MONTANA WHICH WILL GIVE WAY TO A PACIFIC LOW PRESSURE
TROUGH EXPECTED TO MOVE INTO THE REGION BY THURSDAY AFTERNOON. A
CHANCE FOR PRECIPITATION FOR MUCH OF THE CWA THURSDAY AND THURSDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL AS THE FRONT
ADVANCES INTO THE REGION. SAUCIER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 27 23 45 34 / 30 20 0 0
CTB 25 23 44 33 / 40 20 0 0
HLN 36 24 44 27 / 20 10 0 0
BZN 41 20 43 22 / 30 20 0 0
WEY 31 12 32 10 / 30 20 10 0
DLN 41 19 41 20 / 10 10 0 0
HVR 8 5 33 16 / 80 50 10 0
LWT 27 18 41 28 / 100 60 10 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR MTZ011-
013-047-050-051.
&&
$$
SHORT TERM...MPJ
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...WARANAUSKAS
WEATHER.GOV/GREATFALLS
000
FXUS65 KBYZ 141702
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
1002 AM MST WED JAN 14 2009
.SHORT TERM...VALID FOR TDY AND THU...
NO CHANGES TO WINTER WEATHER ADVISORIES THIS MORNING. UPDATE
CHALLENGE THIS MORNING TO DETERMINE HOW FAR WEST THE COLD FRONT
WILL PRESS AND SUBSEQUENTLY WHERE THE WEST EDGE OF THE HEAVIER
SNOW BAND WILL BE THROUGH THE DAY. CURRENTLY THE WEST EDGE OF THE
BAND IS FROM WEST OF ROUNDUP TO A FEW MILES EAST OF BILLINGS TO
AROUND ST. XAVIER IN WESTERN BIG HORN COUNTY. THIS IS DESPITE THE
COLD FRONT BEING LOCATED AROUND THE BIG TIMBER AREA AND COLD AIR
BEING 3 TO 4KFT DEEP OVER BILLINGS. DOWNSLOPING OFF THE SNOWY
MOUNTAINS FROM STRONG NORTHWEST WINDS ALOFT SEEMS TO BE THE
CULPRIT WITH THE SHARP SNOW/NO SNOW LINE IN THE BILLINGS AREA.
OVER THE PAST HALF HOUR OR SO RADAR HAS BEGUN TO SNOW RETURNS OVER
GOLDEN VALLEY AND WESTERN MUSSELSHELL COUNTY THOUGH...THUS THE
COLD AIRMASS MAY BEE DEEPENING ENOUGH THAT THIS DOWNSLOPE IS
COMING TO AN END AND WILL SEE THE WESTERN EDGE OF THE SNOW BAND
SHIFT WESTWARD THROUGH MID AFTERNOON. ON THE EAST EDGE THE SNOW
HAS BEEN HEAVIER THAN ADVERTISED BY THE MODELS IN MILES CITY AND
HAVE INCREASED POPS AND SNOW ACCUMULATIONS FOR WESTERN CUSTER
COUNTY AS A RESULT. DO NOT ANTICIPATE ADVISORY TYPE SNOW
ACCUMULATIONS BUT COULD BE SOME 2 TO 3 INCH AMOUNTS OVER THE
SOUTHWEST CORNER OF CUSTER COUNTY BY THE TIME SNOW DIMINISHES LATE
TONIGHT. IN THE HEART OF THE SNOW BAND HAVE SEEN ACCUMULATIONS
FROM AN INCH TO 3 INCHES FROM TREASURE THROUGH BIG HORN AND INTO
SHERIDAN COUNTY. INCREASED POPS TO 100 PERCENT FOR THE REST OF
TODAY FOR CENTRAL AREAS AND SPREAD HIGH CHANCE POPS FURTHER EAST
INTO CARTER COUNTY BASED ON THE BROADER EXTENT OF THE SNOW INTO
THE COLDER AIR EAST.
PRECIPITATION FOR BILLINGS...RADAR RETURNS AND THE DEEPER COLDER
AIR OVER THE AREA THIS MORNING STILL POINT TO ACCUMULATING SNOW IN
THE BILLINGS AREA TODAY...THOUGH AMOUNTS LOOK TO BE AROUND AN INCH
IN TOWN. AS WARM ADVECTION KICKS IN ALOFT THIS EVENING SHOULD SEE
SNOW CONTINUE THROUGH MUCH OF THE NIGHT WITH AN ADDITIONAL INCH OR
TWO. EASTERN YELLOWSTONE COUNTY WILL SEE THE MORE SIGNIFICANT SNOW
WITH AROUND 2 INCHES ON THE GROUND ALREADY AND AN ADDITIONAL 4 TO
5 INCHES EXPECTED THERE THIS AFTERNOON THROUGH TONIGHT. THE
DIVIDING LINE BETWEEN THE LESSER AND GREATER ACCUMULATIONS LOOKS
TO BE AROUND SHEPHERD AND HUNTLEY.
TEMPERATURES...WENT WITH HIGH TEMPERATURES BEING THE CURRENT
TEMPERATURES AROUND 9 AM. COLDER AIR HAS DEFINITELY PUSHED FURTHER
WEST THAN MODELS ANTICIPATED WITH BILLINGS ALREADY A GOOD 5 TO 8
DEGREES COLDER THAN THE COLDEST MODEL GUIDANCE THIS MORNING. THIS
IS NOT UNCOMMON GIVEN THE SHALLOW NATURE OF THE COLD AIR IN
PROXIMITY TO THE NEARBY MOUNTAINS. OVERALL EXPECT TEMPERATURES TO
HOLD STEADY WEST AND CENTRAL...AND POSSIBLY FALL SLIGHTLY OVER THE
EAST WHERE ANOTHER IMPULSE WILL DRIVE EVEN COLDER AIR OUT OF
SOUTHERN CANADA AND INTO THE NORTHERN PLAINS THIS AFTERNOON.
REST OF THE FORECAST LOOKS TO BE IN GOOD SHAPE. CHAMBERS
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MODELS CONTINUE TO BE CONSISTENT IN BRINGING A STRONG RIDGE OVER
THE FORECAST AREA FOR THE WEEKEND AND INTO EARLY NEXT WEEK. THIS
WILL RESULT IN MUCH ABOVE NORMAL TEMPERATURES ACROSS MOST OF THE
PLAINS. MODELS STILL SHOWING RISING HEIGHTS BEGINNING FRIDAY EVEN
AS THE FLOW ALOFT REMAINS NORTHWEST. A WEAK DISTURBANCE MOVES
SOUTH OUT OF CANADA FRIDAY NIGHT INTO SATURDAY MORNING. WILL
CONTINUE WITH A SLIGHT CHANCE FOR A SNOW SHOWER ACROSS THE FAR
EASTERN ZONES DURING THIS TIME. HOWEVER...EACH SUCCESSIVE MODEL
RUN SHOWING A DECREASE IN MOISTURE SO HAVE TRIMMED THE WESTERN
PORTIONS OF THE POPS TO JUST INCLUDE MAINLY
CUSTER...CARTER...POWDER RIVER AND FALLON COUNTIES.
AFTER THIS WEAKER CLIPPER TYPE SYSTEM MOVES ACROSS THE
EAST...EXPECT HIGH PRESSURE TO BUILD EVEN MORE FOR SUNDAY AND
MONDAY ACROSS THE ENTIRE FORECAST AREA. GUIDANCE NOW COMING IN
WITH MIDDLE 50S FOR HIGHS MONDAY FOR BILLINGS. WOULD NOT BE
SURPRISED TO SEE AN ISOLATED 60 DEGREE READING. HAVE
THEREFORE...WARMED TEMPERATURES ACROSS THE CENTRAL ZONES ABOUT 5
DEGREES FOR THIS TIME. A WEAK FRONT MOVES THROUGH MONDAY NIGHT
BRINGING COOLER TEMPERATURES FOR TUESDAY AND WEDNESDAY BUT STILL
ABOVE NORMAL. NEXT SYSTEM LOOKS TO ARRIVE LATE WEDNESDAY WITH THE
POSSIBILITY OF MUCH COLDER TEMPERATURES ALONG WITH SNOW. BUT THERE
IS STILL PLENTY OF TIME FOR MODELS TO WAIVER BUT SOMETHING TO
KEEP AN EYE ON. HOOLEY
&&
.AVIATION...
A STATIONARY ARCTIC FRONT 80 TO 100 MILES WEST OF KBIL WILL CAUSE
A STRIP OF IFR TO LIFR CONDITIONS 100 MILES EAST AND WEST OF A
LINE FROM KLWT TO KBIL TO KSHR DUE TO SNOW AND CEILINGS. EAST AND
WEST OF THIS AREA MOSTLY VFR CONDITIONS ARE EXPECTED THOUGH
ISOLATED SNOW SHOWERS MAY CREATE BRIEF MVFR CONDITIONS. LITTLE
CHANGE IS EXPECTED IN THIS PATTERN UNTIL AFTER MIDNIGHT. BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 026 015/038 031/048 035/050 032/052 036/056 036/044
+/S 82/S 00/N 00/U 00/U 00/U 00/U
LVM 039 025/048 036/051 038/051 030/052 035/055 035/044
2/O 20/N 00/N 00/U 00/U 00/U 00/U
HDN 021 008/034 023/046 029/049 029/052 029/054 029/046
+/S 83/S 00/U 00/U 00/U 00/U 00/U
MLS 004 906/021 014/042 027/043 022/048 027/052 027/041
+/S 42/S 00/U 22/S 00/U 00/U 00/U
4BQ 010 903/029 019/052 030/051 026/051 028/053 028/046
+/S 73/S 00/U 22/S 00/U 00/U 00/U
BHK 904 912/018 010/046 022/040 020/046 023/052 023/040
2/S 12/S 20/U 22/S 00/U 00/U 00/U
SHR 030 014/037 024/053 026/050 025/052 026/054 026/047
+/S 93/S 00/U 00/U 00/U 00/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONES 29-35-38-57.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 3 AM MST THURSDAY FOR
ZONES 30-31-36-58.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
000
FXUS65 KTFX 141155
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
440 AM MST WED JAN 14 2009
AVIATION SECTION UPDATED...
.DISCUSSION...
WEDNESDAY THROUGH FRIDAY...PRECIP IS CURRENTLY FALLING OVER THE
EASTER PART OF THE CWA IN ASSOCIATION WITH THE THE COLD FRONT THAT
IS MOVING THROUGH THE AREA. EXPECTING TO SEE SCATTERED SNOW
SHOWERS THROUGH THE REST OF THE DAY ESPECIALLY OVER FERGUS AND
BLAINE COUNTIES. ACCUMULATIONS FROM THIS SYSTEM SHOULD REMAIN
BELOW WARNING CRITERIA AND HAVE STUCK WITH AN ADVISORY AT THIS
POINT. NOT ANTICIPATING AN UPGRADE WITH THIS SYSTEM...BUT WILL
CONTINUE TO MONITOR IN CASE SOME INCREASED INSTABILITY BEGINS TO
CAUSE BANDING. OTHERWISE A RELATIVELY CALM SITUATION FOR THE REST
OF THE PERIOD AS A UPPER LEVEL RIDGE OF HIGH PRESSURE BEGINS TO
BUILD AND EXERT ITS INFLUENCE. TEMPERATURES SHOULD WARM
DRAMATICALLY AS THE UPPER LEVEL MOISTURE IS CUT OFF AND THE SKIES
BEGIN TO CLEAR FOR NEXT COUPLE OF DAYS.
FRIDAY NIGHT THROUGH MONDAY NIGHT. ALL MODELS STILL ON TRACK IN
SHOWING ARRIVAL OF STRONG PACIFIC UPPER RIDGE OVER THE WESTERN US
DURING THIS PERIOD. LEADING EDGE OF THE RIDGE EXTENDS ALL THE WAY
INTO ERN MT BY FRIDAY NIGHT. AIRMASS ACROSS CENTRAL AND SOUTHWEST MT
WILL BECOME PROGRESSIVELY DRIER AND WARMER THROUGH THE WEEKEND. A
WEAK SHORTWAVE TROF COMES DOWN THE EAST SIDE OF THE RIDGE ON SAT BUT
SHOULD PRODUCE LITTLE MORE THAN SLIGHTLY INCREASED HIGH CLOUD COVER
OVER THE REGION. UPPER RIDGE AXIS WILL BE CENTERED ALONG THE
CONTINENTAL DIVIDE BY MONDAY AS RIDGE MAKE SLOW PROGRESSION TO THE
EAST. KEPT PREVIOUS SHIFTS DECISION TO GO SEVERAL DEGREES ABOVE
GUIDANCE FOR MAX TEMPS ON SAT AND SUN AS CLEAR TO SCATTERED SKIES
WILL PROVIDE EXTENDED PERIODS OF SUNSHINE. THIS WILL CAUSE RAPID
MELTING OF CURRENT SNOW COVER IN THE PLAINS ALLOWING LOW LEVEL TEMPS
TO WARM SIGNIFICANTLY...AS EVIDENCED BY MODEL FORECASTS OF TEMPS IN
LOW-MID 50S UP TO 850 MB/5000 FT ELEV ON SUN AFTN. WARANAUSKAS
TUESDAY AND WEDNESDAY...CURRENT MODELS DEPICT A HIGH PRESSURE RIDGE
OVER CENTRAL MONTANA WHICH WILL GIVE WAY TO A PACIFIC LOW PRESSURE
TROUGH EXPECTED TO MOVE INTO THE REGION BY THURSDAY AFTERNOON. A
CHANCE FOR PRECIPITATION FOR MUCH OF THE CWA THURSDAY AND THURSDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL AS THE FRONT
ADVANCES INTO THE REGION. SAUCIER
&&
.AVIATION...
UPDATED 14/1140Z.
PERSISTENT MOIST NORTHWEST FLOW ALOFT WILL KEEP BROAD AREA OF LOW-
AND MID-LEVEL CLOUDS OVER CENTRAL AND SOUTHWEST MT TODAY. A SURFACE
FRONTAL BOUNDARY OVER NORTH CENTRAL MONTANA CONTINUES TO SLOWLY
DRIFT TO THE WEST-SOUTHWEST WITH LIGHT SNOW ALONG AND WEST OF THE
FRONT. THE FRONT SHOULD BECOME NEARLY STATIONARY THIS AFTN ALONG A
KCTB-TO-KBIL LINE AND ADDITIONAL MOISTURE DROPPING SOUTH OUT OF
CANADA WILL GENERATE AREAS OF LIGHT SNOW ACROSS CENTRAL MT. BEST
CHANCE OF ACCUMULATING SNOW FROM KHVR TO KLWT AS THEY WILL BE ON THE
COLD AIR SIDE OF THE FRONT. CEILINGS WILL BE A MIX OF VFR AND MVFR
FOR MUCH OF THE DAY...WITH IFR CONDITIONS POSSIBLE NEAR
PRECIPITATION AREAS. THE FRONTAL SYSTEM SHOULD SLIDE EASTWARD
TONIGHT AS STRONG HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE
PACIFIC ON THURS...GRADUALLY ENDING THE SNOW AND RAISING CEILINGS
TO VFR FROM WEST TO EAST. WARANAUSKAS
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 30 23 45 34 / 50 20 0 0
CTB 31 23 44 33 / 40 20 0 0
HLN 37 24 44 27 / 20 10 0 0
BZN 38 20 43 22 / 30 20 0 0
WEY 31 12 32 10 / 30 20 10 0
DLN 34 19 41 20 / 10 10 0 0
HVR 12 5 33 16 / 80 50 10 0
LWT 25 18 41 28 / 80 60 10 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR MTZ011-
013-047-050-051.
&&
$$
SHORT TERM...SUK
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...WARANAUSKAS/SAUCIER
WEATHER.GOV/GREATFALLS
000
FXUS65 KTFX 141103
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
403 AM MST WED JAN 14 2009
.DISCUSSION...
WEDNESDAY THROUGH FRIDAY...PRECIP IS CURRENTLY FALLING OVER THE
EASTER PART OF THE CWA IN ASSOCIATION WITH THE THE COLD FRONT THAT
IS MOVING THROUGH THE AREA. EXPECTING TO SEE SCATTERED SNOW
SHOWERS THROUGH THE REST OF THE DAY ESPECIALLY OVER FERGUS AND
BLAINE COUNTIES. ACCUMULATIONS FROM THIS SYSTEM SHOULD REMAIN
BELOW WARNING CRITERIA AND HAVE STUCK WITH AN ADVISORY AT THIS
POINT. NOT ANTICIPATING AN UPGRADE WITH THIS SYSTEM...BUT WILL
CONTINUE TO MONITOR IN CASE SOME INCREASED INSTABILITY BEGINS TO
CAUSE BANDING. OTHERWISE A RELATIVELY CALM SITUATION FOR THE REST
OF THE PERIOD AS A UPPER LEVEL RIDGE OF HIGH PRESSURE BEGINS TO
BUILD AND EXERT ITS INFLUENCE. TEMPERATURES SHOULD WARM
DRAMATICALLY AS THE UPPER LEVEL MOISTURE IS CUT OFF AND THE SKIES
BEGIN TO CLEAR FOR NEXT COUPLE OF DAYS.
FRIDAY NIGHT THROUGH MONDAY NIGHT. ALL MODELS STILL ON TRACK IN SHOWING
ARRIVAL OF STRONG PACIFIC UPPER RIDGE OVER THE WESTERN US DURING
THIS PERIOD. LEADING EDGE OF THE RIDGE EXTENDS ALL THE WAY INTO ERN
MT BY FRIDAY NIGHT. AIRMASS ACROSS CENTRAL AND SOUTHWEST MT WILL
BECOME PROGRESSIVELY DRIER AND WARMER THROUGH THE WEEKEND. A WEAK
SHORTWAVE TROF COMES DOWN THE EAST SIDE OF THE RIDGE ON SAT BUT SHOULD
PRODUCE LITTLE MORE THAN SLIGHTLY INCREASED HIGH CLOUD COVER OVER
THE REGION. UPPER RIDGE AXIS WILL BE CENTERED ALONG THE CONTINENTAL
DIVIDE BY MONDAY AS RIDGE MAKE SLOW PROGRESSION TO THE EAST. KEPT
PREVIOUS SHIFTS DECISION TO GO SEVERAL DEGREES ABOVE GUIDANCE FOR
MAX TEMPS ON SAT AND SUN AS CLEAR TO SCATTERED SKIES WILL PROVIDE
EXTENDED PERIODS OF SUNSHINE. THIS WILL CAUSE RAPID MELTING OF CURRENT
SNOW COVER IN THE PLAINS ALLOWING LOW LEVEL TEMPS TO WARM
SIGNIFICANTLY...AS EVIDENCED BY MODEL FORECASTS OF TEMPS IN LOW-MID
50S UP TO 850 MB/5000 FT ELEV ON SUN AFTN. WARANAUSKAS
TUESDAY AND WEDNESDAY...CURRENT MODELS DEPICT A HIGH PRESSURE RIDGE
OVER CENTRAL MONTANA WHICH WILL GIVE WAY TO A PACIFIC LOW PRESSURE
TROUGH EXPECTED TO MOVE INTO THE REGION BY THURSDAY AFTERNOON. A
CHANCE FOR PRECIPITATION FOR MUCH OF THE CWA THURSDAY AND THURSDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE NEAR SEASONAL AS THE FRONT
ADVANCES INTO THE REGION. SAUCIER
&&
.AVIATION...
UPDATED 0550Z.
MOIST NORTHWEST FLOW ALOFT CONTINUES. A SURFACE FRONTAL BOUNDARY
OVER NORTHEAST MONTANA CONTINUES TO SLIDE SOUTH AND WEST AND SHOULD
REACH A KCTB TO KBIL LINE BY WEDNESDAY MORNING. LIGHT SNOW AND
LOWERING CEILINGS ARE DEVELOPING NORTH AND EAST OF THIS LINE. VFR
CONDITIONS WILL PREVAIL THIS EVENING BUT WILL BECOME MVFR/IFR NORTH
AND EAST OF THE FRONTAL BOUNDARY DUE TO LOW CEILINGS AND SNOW. KHVR
AND KLWT WILL LIKELY EXPERIENCE THE GREATEST IMPACT AS THEY WILL BE
IN THE COLD SECTOR OF THE FRONT AND REMAIN THERE THROUGH WEDNESDAY
MORNING. HIGHER TERRAIN WILL BECOME OBSCURED NORTH AND EAST OF THE
AFOREMENTIONED FRONTAL BOUNDARY.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 30 23 45 34 / 50 20 0 0
CTB 31 23 44 33 / 40 20 0 0
HLN 37 24 44 27 / 20 10 0 0
BZN 38 20 43 22 / 30 20 0 0
WEY 31 12 32 10 / 30 20 10 0
DLN 34 19 41 20 / 10 10 0 0
HVR 12 5 33 16 / 80 50 10 0
LWT 25 18 41 28 / 80 60 10 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR MTZ011-
013-047-050-051.
&&
$$
SHORT TERM...SUK
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...WARANAUSKAS/SAUCIER
WEATHER.GOV/GREATFALLS
000
FXUS65 KBYZ 141024
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
324 AM MST WED JAN 14 2009
.SHORT TERM...VALID FOR TDY AND THU...
AREA OF SNOW HAS DEVELOPED BETWEEN KBIL AND KMLS...IN A BAND
EXTENDING SOUTH TO KSHR. SURFACE BOUNDARY HAS MADE IT AS FAR WEST
AS BIG TIMBER AS OF 10Z...ALREADY FURTHER WEST THAN MODELS
INDICATE...BUT IT IS SHALLOW AND TEMPS HAVE BEEN VERY SLOW TO
RESPOND IN OUR WEST. LIGHT WEST WIND CONTINUES AT KLVM WHERE IT IS
STILL 45F...AND IN THE EAST IT IS 1 BELOW AT KBHK.
PCPN SO FAR HAS BEEN HEAVIEST IN UPSLOPE AREAS OF BIG HORN AND
SHERIDAN COUNTIES. FLOW HAS BEEN TOO NW FOR ANYTHING MORE THAN
FLURRIES AT KBIL. WATER VAPOR IMAGERY SHOWS ENERGY PUSHING
SOUTHWARD FROM SASKATCHEWAN INTO NE MONTANA...AND AS THIS PASSES
WE SHOULD SEE MID LEVEL FLOW VEER FURTHER TO A MORE NORTHERLY
DIRECTION. WITH THIS IN MIND AND AS COLD AIR DEEPENS...AND KBLX
VAD WINDS SHOW THIS IS HAPPENING...DOWNSLOPING SHOULD BE
ELIMINATED AND WOULD EXPECT SNOW TO GET INTO KBIL AS WELL SOMETIME
EARLY THIS MORNING.
CURRENT LOCATION OF ADVISORIES LOOK GOOD AND WILL MAKE NO
CHANGES...EXCEPT TO LOWER ACCUMS A BIT AT BILLINGS AND ROUNDUP AND
RAISE THEM A BIT AT FORT SMITH AND SHERIDAN WHERE UPSLOPE SHOULD
YIELD THE GREATEST AMOUNTS OVER THE DURATION OF THIS EVENT. TOTALS
SHOULD RANGE FROM 3 TO 7 INCHES OVER THE NEXT 24 HOURS. THOUGH
WINDS AT KLVM MAY ACTUALLY TURN EAST...IT APPEARS ANY SIGNIFICANT
PCPN WILL STAY EAST OF THERE WHERE MID LEVEL BAROCLINIC ZONE LIES.
AGAIN MUST STRESS THAT EVEN THOUGH PCPN TO THIS POINT HAS BEEN
LIGHT...AS DENDRITIC LAYER DEEPENS WITH CONTINUED COOLING THE BAND
OF SNOW SHOULD INTENSIFY SOMEWHAT. PCPN WILL TAPER OFF LATE
TONIGHT AS FLOW ALOFT TRENDS TOWARD ANTICYCLONIC WITH ONSET OF
RISING HEIGHTS. SHOULD STILL SEE SOME LIGHT SNOW PERSIST THURSDAY
IN OUR EAST HALF...POSSIBLY INTO THE EVENING IN THE FAR EAST
BEFORE WARM FRONT BLOWS THROUGH. WARM ADVECTION SHOULD BE STRONG
THU NIGHT AS LEE TROFFING INTENSIFIES AND MUCH WARMER AIR SPILLS
DOWN FROM THE EAST SLOPES OF THE CANADIAN ROCKIES.
WILL HOLD OFF ON A WIND CHILL HIGHLIGHT IN OUR NE AS WINDS ARE
STEADILY COMING DOWN...THOUGH WITH TEMPS AROUND ZERO WIND CHILLS
ARE CURRENTLY AROUND 20 BELOW IN FALLON COUNTY.
TRICKY TEMP FORECAST AS LOW LEVEL COLD AIR SURGES IN FROM THE NE
TODAY. TEMPS WILL STRUGGLE TO RISE AT ALL IN THE EAST...AND SHOULD
STEADILY FALL IN OUR WEST. COLD AIR BEGINS TO RETREAT TOMORROW AND
DOWNSLOPE FLOW IN OUR WEST ON THU SHOULD ALLOW FOR A VERY MILD DAY
ALONG OUR EASTERN SLOPES. WILL LIKELY SEE RISING TEMPS THU NIGHT
PER AFOREMENTIONED WARM ADVECTION. DESPITE THE NW FLOW GFS/ECMWF/NAM
SHOW 850MB TEMPS TO 5-10C BY FRI 12Z.
JKL
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MODELS CONTINUE TO BE CONSISTENT IN BRINGING A STRONG RIDGE OVER
THE FORECAST AREA FOR THE WEEKEND AND INTO EARLY NEXT WEEK. THIS
WILL RESULT IN MUCH ABOVE NORMAL TEMPERATURES ACROSS MOST OF THE
PLAINS. MODELS STILL SHOWING RISING HEIGHTS BEGINNING FRIDAY EVEN
AS THE FLOW ALOFT REMAINS NORTHWEST. A WEAK DISTURBANCE MOVES
SOUTH OUT OF CANADA FRIDAY NIGHT INTO SATURDAY MORNING. WILL
CONTINUE WITH A SLIGHT CHANCE FOR A SNOW SHOWER ACROSS THE FAR
EASTERN ZONES DURING THIS TIME. HOWEVER...EACH SUCCESSIVE MODEL
RUN SHOWING A DECREASE IN MOISTURE SO HAVE TRIMMED THE WESTERN
PORTIONS OF THE POPS TO JUST INCLUDE MAINLY
CUSTER...CARTER...POWDER RIVER AND FALLON COUNTIES.
AFTER THIS WEAKER CLIPPER TYPE SYSTEM MOVES ACROSS THE
EAST...EXPECT HIGH PRESSURE TO BUILD EVEN MORE FOR SUNDAY AND
MONDAY ACROSS THE ENTIRE FORECAST AREA. GUIDANCE NOW COMING IN
WITH MIDDLE 50S FOR HIGHS MONDAY FOR BILLINGS. WOULD NOT BE
SURPRISED TO SEE AN ISOLATED 60 DEGREE READING. HAVE
THEREFORE...WARMED TEMPERATURES ACROSS THE CENTRAL ZONES ABOUT 5
DEGREES FOR THIS TIME. A WEAK FRONT MOVES THROUGH MONDAY NIGHT
BRINGING COOLER TEMPERATURES FOR TUESDAY AND WEDNESDAY BUT STILL
ABOVE NORMAL. NEXT SYSTEM LOOKS TO ARRIVE LATE WEDNESDAY WITH THE
POSSIBILITY OF MUCH COLDER TEMPERATURES ALONG WITH SNOW. BUT THERE
IS STILL PLENTY OF TIME FOR MODELS TO WAIVER BUT SOMETHING TO
KEEP AN EYE ON. HOOLEY
&&
.AVIATION...
AN ARCTIC FRONT WILL BE SITUATED BETWEEN KBIL AND KLVM TODAY.
ALONG AND EAST OF THE FRONT...AREAS OF LIGHT TO MODERATE SNOW
WILL BE LIKELY THROUGHOUT THE DAY. THE BEST CHANCES FOR HEAVIER
SNOW WILL MAINLY BE FROM KBIL-KSHR TO ABOUT 80 MILES EAST OF THIS
LINE. ELSEWHERE...LIGHTER SNOW OR SNOW SHOWERS CAN BE EXPECTED.
WITHIN THE ABOVE MENTIONED SNOW AREAS...VFR CONDITIONS WILL LOWER
TO MVFR AND IFR CONDITIONS. ELSEWHERE...VFR CONDITIONS ARE
EXPECTED TO PREVAIL. HEAVIER SNOW CAN ALSO BE EXPECTED ALONG THE
UPSLOPE REGIONS OF THE BEARTOOTH/ABSAROKA AND BIG HORN MOUNTAINS
WITH MOUNTAIN OBSCURATIONS LIKELY. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 028 018/038 031/048 035/050 032/052 036/056 036/044
9/S 82/S 00/N 00/U 00/U 00/U 00/U
LVM 037 025/048 036/051 038/051 030/052 035/055 035/044
3/S 20/N 00/N 00/U 00/U 00/U 00/U
HDN 026 010/034 023/046 029/049 029/052 029/054 029/046
+/S 83/S 00/U 00/U 00/U 00/U 00/U
MLS 008 903/021 014/042 027/043 022/048 027/052 027/041
5/S 42/S 00/U 22/S 00/U 00/U 00/U
4BQ 015 901/029 019/052 030/051 026/051 028/053 028/046
9/S 73/S 00/U 22/S 00/U 00/U 00/U
BHK 000 908/018 010/046 022/040 020/046 023/052 023/040
2/S 12/S 20/U 22/S 00/U 00/U 00/U
SHR 027 014/037 024/053 026/050 025/052 026/054 026/047
+/S 93/S 00/U 00/U 00/U 00/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONES 29-35-38-57.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 3 AM MST THURSDAY FOR
ZONES 30-31-36-58.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST THURSDAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
000
FXUS65 KGGW 141020
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
320 AM MST WED JAN 14 2009
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
COLD SURFACE HIGH PRESSURE WILL MAKE ITS WAY INTO MOST OF THE CWA
TODAY FROM THE NORTH MAKING FOR A MUCH COLDER DAY THAN YESTERDAY
AND FORCING THE FRONTAL BOUNDARY SOUTH AND WEST TO THE SOUTHWEST
CORNER OF THE CWA WHERE IT HANGS UP. ALOFT SOME CHANNELED
VORTICITY ALONG THE FRONT WILL AID IN KEEPING LIGHT PRECIPITATION
GOING THERE TODAY. CURRENT THINKING IS THAT SNOW...ALTHO LIKELY
CONTINUOUS OR CLOSE TO IT...WILL BE VERY LIGHT AND ACCUMULATE
SLOWLY. OVERALL NOT EXPECTING MORE THAN ABOUT 2 INCHES OR SO WHEN
ALL IS SAID AND DONE...BUT THAT COMES OVER A RATHER LONG PERIOD SO
AS TO PRECLUDE A SNOW ADVISORY. WILL DROP THE CURRENT WIND CHILL
ADVISORY IN THE NORTHEAST HALF OF THE CWA AS WIND ALREADY DOWN
BELOW 10 MPH IN MOST SPOTS DUE TO THE SURFACE HIGH SETTLING IN
THERE. SURFACE HIGH SLIDES SOUTHEAST ACROSS THE AREA TONIGHT AND
EFFECTS OF THE QUASI- STATIONARY FRONTAL BOUNDARY OVER THE
SOUTHWEST WEAKEN AS UPPER SUPPORT WANES. UPPER PATTERN REMAINS
VERY AMPLIFIED OVER NORTH AMERICA THURSDAY WITH A RIDGE IN THE
WEST AND A TROF IN THE EAST. WESTERN RIDGE FINALLY BEGINS FLEXING
ITS MUSCLE EAST AND BRINGS WARMER AIR WITH IT. THE QUASI-
STATIONARY BOUNDARY GETS PUSHED EAST AS A SURFACE TROF DEVELOPS
OVER CENTRAL MONTANA. COULD BE SOME VERY SPOTTY AND VERY LIGHT
OVERRUNNING PRECIPITATION THURSDAY...BUT NOT REALLY SEEING ENUF
REASONS TO RAISE POPS AT THIS POINT. TEMPERATURES BEGIN MODERATING
TOMORROW WITH THE ADVECTION OF THE WARMER AIR...BUT A LACK OF
MIXING FOR ALL BUT THE SOUTHWEST SHOULD PRECLUDE ANY REALLY LARGE
WARMUP FOR MOST. WARM AIR ADVECTION REALLY BEGINS IN EARNEST
THURSDAY NIGHT AND THE PASSAGE OF THE SURFACE TROF SHOULD CREATE
SOME MIXING. FRIDAY THE WARM AIR GETS TEMPERED A BIT BY A WEAK
DISTURBANCE ALOFT WHICH ALLOWS FOR A BRIEF DECREASE IN UPPER
HEIGHTS AND THICKNESSES...AND DROPS THE 850 MB TEMPERATURES A BIT.
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE EXPECTED MID-WINTER INTERLUDE OF SEVERAL DAYS OF DRY AND
MILDER WEATHER...CONTINUES ON TRACK. IN A CONTINUED VERY
AMPLIFIED PATTERN...THE STRONG UPPER HIGH WITH A CLOSED CENTER
OVER OR/WA SLOWLY MOVES E DURING MOST OF THE PERIOD... REACHING S MT.
MODELS REMAIN IN EXCELLENT AGREEMENT WITH THIS. THICKNESSES CLIMB
TO 560 MB BY MON...WITH SOME 850 MODEL TEMPS AS HIGH AT 17C. AS
ALMOST ALWAYS IN JAN...ANYTHING EVEN CLOSE TO FULL WARMING
POTENTIAL WILL NOT OCCUR DUE TO ENERGY NEEDED TO MELT THE HEAVY
SNOWPACK. LOW-LEVEL ARE FROM A DOWNSLOPING W-NW COMPONENT...BUT
NOT THAT STRONG WITH SURFACE HIGH CENTER NEAR OUR AREA. CERTAINLY
MOST OF THE AREA S OF MISSOURI RIVER WHERE SNOWCOVER IS
LESS...WILL GO TO BARE GROUND ALLOWING TEMPS TO REACH THE 50S MON.
SOME MODELS HAVE SHOWN A WEAK SHORTWAVE MOVE THRU NE MT DIRECTLY
FORM THE N ABOUT SAT...BUT LOOKING VERY DRY AS IT GETS CAUGHT UP
AND TORN APART ANTI-CYCLONIC UPPER HIGH CIRCULATION. MODELS LOOK VERY
DRY DURING THE PERIOD EVEN IN LOWER LEVELS...SO SEVERAL DAYS OF
FULL SUNSHINE ALSO EXPECTED. EXPECT THERE COULD BE SOME PATCHY FOG
IN THE MORNING THOUGH...WITH SNOWMELT AND CLEAR SKIES...BUT FLOW
IS MORE OR LESS A DOWNSLOPING W FLOW IN THE LOWER LEVELS.
ALL MODELS ARE NOW INDICATING A CHANGE LATE IN THE PERIOD...WITH
THE UPPER HIGH FADING AWAY...WHILE ANOTHER HIGH BUILDS OVER THE
GULF OF AK. THIS WILL ALLOW AN ARCTIC COLD FRONT TO PUSH INTO NE
MT FOR COLDER WEATHER AND A THREAT OF SOME SNOW BY WED. SIMONSEN
&&
.AVIATION...
MVFR CEILINGS AT TIMES AROUND OVERCAST 3K FT AGL WILL CONTINUE
ACROSS MOST OF THE AREA THIS MORNING. OVER ROUGHLY THE SW THIRD
OF THE FORECAST AREA...S-SW PHILLPS..PETROALUM...SW GARFIELD
COUNTIES...LIGHT SNOW WILL ALSO REDUCE VISIBILITY TO MVFR 3-5
MILES. PARTIAL CLEARING OF THE LOWER CLOUD LAYER CLEARING SKIES
NOW JUST REACHING EXTREME NE MT...SHERIDAN COUNTY...WILL SLOWLY
EXPAND SW TODAY...WITH THE LOWER CLOUD LAYER BECOMING SCATTERED
DURING THE AFTERNOON AT TAF SITES GGW...OLF..SDY...AND GDV. THE
MVFR CONDITIONS WITH SNOW AND LOWER OVERCAST OVER OUR SW THIRD OF
THE FORECAST AREA THOUGH WILL LINGER INTO TONIGHT. SIMONSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
000
FXUS65 KMSO 140959
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
259 AM MST WED JAN 14 2009
...INCREASING FOG AND AIR QUALITY CONCERNS ARE LIKELY FROM
THURSDAY NIGHT THROUGH THE WEEKEND...
.DISCUSSION...THE NORTHWEST FLOW ALOFT WILL CONTINUE TODAY AND
TONIGHT...BUT MID LEVEL MOISTURE WILL BE LIMITED. STILL...AREAS
CLOSER TO THE CONTINENTAL DIVIDE COULD SEE SOME VERY LIGHT SNOW.
PATCHY FOG WILL PERSIST THROUGH THE MORNING IN NORTH CENTRAL IDAHO
VALLEYS AND ALSO THE VALLEYS IN NORTHWEST MONTANA WHERE CLEARING
HAS ALLOWED MORE RADIATIONAL COOLING TO TAKE PLACE.
GENERAL MIXING OF THE LOWER ATMOSPHERE WILL SLOWLY DIMINISH TODAY
AND TONIGHT AS HIGH PRESSURE STRENGTHENS BOTH AT THE SURFACE AND
ALOFT. THEREFORE...THE VALLEYS OF WEST CENTRAL AND SOUTHWEST
MONTANA ARE EXPECTED TO BE MUCH COOLER TONIGHT THAN THE MILD
TEMPERATURES EXPERIENCED THE PAST WEEK OR SO.
THURSDAY THROUGH MONDAY...A STRONG RIDGE OF HIGH PRESSURE WILL SLOWLY
SHIFT EASTWARD OVER THE REGION. AS THIS OCCURS...THE ATMOSPHERE
WILL BECOME INCREASINGLY STABLE WITH MILD CONDITIONS IN THE
MOUNTAINS AND COLD AIR POOLING IN THE VALLEYS. THE MAIN IMPACT
WILL BE TWO FOLD. FIRST...INCREASING AREAS OF FOG SHOULD OCCUR IN
THE VALLEYS. SECOND...WITH A VERY STABLE ATMOSPHERE...POLLUTANTS
WILL BUILD UP IN THE LOWER ATMOSPHERE.
&&
.AVIATION...VALLEY FOG IS STILL NOT WIDESPREAD THIS MORNING WITH
THE ATMOSPHERE STILL SOMEWHAT MIXED UNDER THE NORTHWEST FLOW
ALOFT. ALTHOUGH...THE VALLEYS OF NORTH CENTRAL AND NORTHWEST
MONTANA WILL SEE SOME FOG THROUGH THE MORNING. FOG COVERAGE AND
DENSITY WILL INCREASE SLIGHTLY TONIGHT WITH ONLY A SMALL
PROGRESSION TO THE UPPER FLOW. HOWEVER...HIGH PRESSURE WILL
DRAMATICALLY STRENGTHEN FRIDAY INTO THE WEEKEND...WITH WIDESPREAD
FOG LIKELY DISRUPTING AIR TRAVEL.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&
$$
SHORT TERM...WHITMORE
LONG TERM....KOLATA
AVIATION...WHITMORE
000
FXUS65 KTFX 140554
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1050 PM MST TUE JAN 13 2009
UPDATED AVIATION SECTION
.DISCUSSION...
MOIST NORTHWEST FLOW IS OVER THE FORECAST AREA. AT THE SURFACE A COLD
FRONT WAS WELL-DEFINED OVER SE MT AND EXTENDED NORTHWEST TO
CENTRAL MONTANA WHERE IT WAS MUCH LESS-DEFINED. HOWEVER
TEMPERATURES WELL BELOW FREEZING WERE STILL CONFINED TO NORTH OF
THE BORDER. EXPECT THAT COOLER AIR WILL CONTINUE TO FILTER SOUTH
THE REST OF TONIGHT. DUE TO EXPECTED CLOUD COVER AND THE FACT THAT
DO NOT EXPECT THE COLD AIR TO REALLY GET INTO SW MT...HAVE RAISED
A FEW LOWS FOR TONIGHT IN THAT REGION. RADAR WAS INDICATING SOME
PROBABLE PRECIPITATION OVER NORTH CENTRAL MONTANA AS OF MID-
EVENING AND HAVE INCREASED POPS THERE A LITTLE. HAVING TROUBLE
FIGURING OUT HOW THE SNOWFALL DETAILS WILL PLAY OUT THE REST OF
TONIGHT INTO WEDNESDAY MORNING. DID INCREASE THE CHANCES OF
PRECIPITATION SOME OVER CENTRAL MONTANA FOR LATER TONIGHT DUE
MAINLY TO OROGRAPHIC EFFECTS. WINTER WEATHER ADVISORY STILL LOOKS
PRETTY GOOD AND WILL CONTINUE IT AS IS. BLANK
&&
.AVIATION...
UPDATED 0550Z.
MOIST NORTHWEST FLOW ALOFT CONTINUES. A SURFACE FRONTAL BOUNDARY
OVER NORTHEAST MONTANA CONTINUES TO SLIDE SOUTH AND WEST AND SHOULD
REACH A KCTB TO KBIL LINE BY WEDNESDAY MORNING. LIGHT SNOW AND
LOWERING CEILINGS ARE DEVELOPING NORTH AND EAST OF THIS LINE. VFR
CONDITIONS WILL PREVAIL THIS EVENING BUT WILL BECOME MVFR/IFR NORTH
AND EAST OF THE FRONTAL BOUNDARY DUE TO LOW CEILINGS AND SNOW. KHVR
AND KLWT WILL LIKELY EXPERIENCE THE GREATEST IMPACT AS THEY WILL BE
IN THE COLD SECTOR OF THE FRONT AND REMAIN THERE THROUGH WEDNESDAY
MORNING. HIGHER TERRAIN WILL BECOME OBSCURED NORTH AND EAST OF THE
AFOREMENTIONED FRONTAL BOUNDARY.
&&
.PREV DISCUSSION...
/ISSUED 435 PM MST TUE JAN 13 2009/
TONIGHT THROUGH THURSDAY...SURFACE LOW PRESSURE SYSTEM CONTINUES
TO ACCELERATE AWAY FROM MONTANA THIS AFTERNOON. AN INVERTED LOW
PRESSURE TROUGH EXTENDS NORTHWEST FROM THIS SYSTEM THROUGH NORTH
CENTRAL MONTANA AND SOUTHERN ALBERTA. MODELS CONTINUE TO BE IN
GOOD AGREEMENT BRINGING THE TROUGH SOUTH WITH WINDS SHIFTING TO
THE NORTH AS A CANADIAN COLD FRONT PUSHES INTO MONTANA. THIS
SOLUTION REMAINS ON TRACK AS SURFACE OBSERVATIONS SHOW THAT THE
COLD FRONT HAS ALREADY PUSHED INTO THE LETHBRIDGE AREA. THIS
FRONT WILL CONTINUE PUSHING INTO MY FORECAST AREA OVERNIGHT WITH
SCATTERED PRECIPITATION DEVELOPING ACROSS MY NORTHEAST ZONES
DURING THE EVENING THEN BECOMING MORE WIDESPREAD ALONG A
CONVERGENCE BOUNDARY THAT SHOULD SET UP ALONG A LINE FROM NEAR
HAVRE TO LEWISTOWN. IT APPEARS THAT SNOW WILL BECOME LIKELY ACROSS
ALL EASTERN PORTIONS OF NORTH CENTRAL MONTANA BY MORNING WITH SNOW
GRADUALLY TAPERING OFF FROM NORTHWEST TO SOUTHEAST DURING THE
AFTERNOON. AM EXPECTING 12 TO 18 HOUR SNOW TOTALS OF 2 TO 5 INCHES
IN THIS AREA SO WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY
FOR SNOW. AT THIS TIME IT DOES NOT APPEAR THAT THE GREAT FALLS
AREA WILL RECEIVE MORE THAN A CHANCE OF SNOW WITH PERHAPS AN INCH
OR SO OF ACCUMULATION. HOWEVER...THERE IS A DANGER THAT THE MODELS
HAVE THE BOUNDARY LOCATED TOO FAR TO THE EAST. IF SO...THERE IS A
POSSIBILITY THAT OVERNIGHT SHIFTS MAY DRASTICALLY INCREASE POPS
AND SNOW AMOUNTS FOR CENTRAL AND WESTERN PORTIONS OF NORTH CENTRAL
MONTANA. RESIDUAL SNOW SHOWERS WILL LINGER ACROSS THE EASTERN
PLAINS WEDNESDAY EVENING BUT SHOULD DIMINISH OVERNIGHT AS THE
CANADIAN AIRMASS SLIDES EAST. BY THURSDAY THE UPPER LEVEL RIDGE
OVER THE WEST COAST SHOULD BEGIN TO EDGE INTO THE NORTHERN ROCKY
MOUNTAIN REGION ALLOWING TEMPERATURES TO INCREASE ONCE AGAIN AS
DOWNSLOPE WINDS REASSERT THEMSELVES AND CLEARING SKIES MOVE INTO
CENTRAL MONTANA. MPJ
THURSDAY NIGHT THROUGH SUNDAY NIGHT. MODELS MAINTAINED GOOD
AGREEMENT ON DEVELOPMENT OF A BROAD AND WELL-AMPLIFIED PACIFIC UPPER
RIDGE THAT WILL DOMINATE THE WEATHER ACROSS THE WESTERN US AND SW
CANADA FOR THE LATTER HALF OF THIS WEEK. THIS WILL LEAD TO SEVERAL
DAYS OF DRY CONDITIONS WITH MAX TEMPERATURES OF 10 TO POSSIBLY AS
HIGH AS 20 DEG ABOVE NORMAL ACROSS ALL ZONES BY SUNDAY. MODELS
STILL DEPICT A COUPLE OF SHORTWAVE TROFS COMING OVER THE TOP OF THE
RIDGE DURING THIS PERIOD BUT THEY ARE NOW SHOWN FURTHER EAST AND
CONSIDERABLY DRIER THAT YESTERDAYS MODEL RUNS...SO HAVE REDUCED SKY
COVER GRIDS DOWN TO MOSTLY CLEAR SKIES THRU SUNDAY. THIS WILL ALLOW
NIGHTTIME TEMPS TO DROP BACK BELOW FREEZING EACH NIGHT SO REFREEZING
OF MELTED SNOW/ICE WILL BE A CONCERN DURING THE MORNING HOURS.
WARANAUSKAS
MONDAY AND TUESDAY...LATEST MODELS DEPICT A HIGH PRESSURE RIDGE
OVER THE WESTERN STATES MONDAY. BY TUESDAY AFTERNOON THE RIDGE IS
EXPECTED TO MOVE SOUTH AS AN APPROACHING LOW PRESSURE TROUGH MOVES
INTO THE PACIFIC NORTHWEST. TEMPERATURES WILL BE ABOVE SEASONAL
AVERAGES FOR MUCH OF THE REGION. SAUCIER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 23 30 23 45 / 60 70 10 0
CTB 20 30 23 45 / 20 20 10 0
HLN 31 36 23 44 / 10 10 10 0
BZN 28 38 20 44 / 10 20 10 0
WEY 15 30 11 31 / 20 20 20 10
DLN 20 34 18 42 / 0 10 10 0
HVR 3 10 5 33 / 60 60 30 10
LWT 18 25 18 42 / 70 70 40 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MST WEDNESDAY FOR MTZ011-013-
047-050-051.
&&
$$
SHORT TERM...BLANK
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...EMANUEL
WEATHER.GOV/GREATFALLS
000
FXUS65 KTFX 140426
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
926 PM MST TUE JAN 13 2009
.UPDATE...
MOIST NORTHWEST FLOW IS OVER THE FORECAST AREA. AT THE SURFACE A COLD
FRONT WAS WELL-DEFINED OVER SE MT AND EXTENDED NORTHWEST TO
CENTRAL MONTANA WHERE IT WAS MUCH LESS-DEFINED. HOWEVER
TEMPERATURES WELL BELOW FREEZING WERE STILL CONFINED TO NORTH OF
THE BORDER. EXPECT THAT COOLER AIR WILL CONTINUE TO FILTER SOUTH
THE REST OF TONIGHT. DUE TO EXPECTED CLOUD COVER AND THE FACT THAT
DO NOT EXPECT THE COLD AIR TO REALLY GET INTO SW MT...HAVE RAISED
A FEW LOWS FOR TONIGHT IN THAT REGION. RADAR WAS INDICATING SOME
PROBABLE PRECIPITATION OVER NORTH CENTRAL MONTANA AS OF MID-
EVENING AND HAVE INCREASED POPS THERE A LITTLE. HAVING TROUBLE
FIGURING OUT HOW THE SNOWFALL DETAILS WILL PLAY OUT THE REST OF
TONIGHT INTO WEDNESDAY MORNING. DID INCREASE THE CHANCES OF
PRECIPITATION SOME OVER CENTRAL MONTANA FOR LATER TONIGHT DUE
MAINLY TO OROGRAPHIC EFFECTS. WINTER WEATHER ADVISORY STILL LOOKS
PRETTY GOOD AND WILL CONTINUE IT AS IS. BLANK
&&
.AVIATION...
UPDATED 2335Z.
MOIST NORTHWEST FLOW ALOFT WILL PERSIST. A SURFACE FRONTAL BOUNDARY
OVER NORTHEAST MONTANA WILL CONTINUE TO SLIDE SOUTH AND
WEST...REACHING A KCTB TO KBIL LINE BY WEDNESDAY MORNING. LIGHT SNOW
AND LOWERING CEILINGS CAN BE EXPECTED NORTH AND EAST OF THIS LINE.
VFR CONDITIONS WILL PREVAIL THIS EVENING BUT BECOME MVFR/IFR NORTH
AND EAST OF THE FRONTAL BOUNDARY AFTER 04Z DUE TO LOW CEILINGS AND
SNOW. KHVR AND KLWT WILL LIKELY EXPERIENCE THE GREATEST IMPACT AS
THEY WILL BE IN THE COLD SECTOR OF THE FRONT AND REMAIN THERE
THROUGH WEDNESDAY MORNING. HIGHER TERRAIN WILL BECOME OBSCURED NORTH
AND EAST OF THE AFOREMENTIONED LINE AFTER 04Z.
&&
.PREV DISCUSSION...
/ISSUED 435 PM MST TUE JAN 13 2009/
TONIGHT THROUGH THURSDAY...SURFACE LOW PRESSURE SYSTEM CONTINUES
TO ACCELERATE AWAY FROM MONTANA THIS AFTERNOON. AN INVERTED LOW
PRESSURE TROUGH EXTENDS NORTHWEST FROM THIS SYSTEM THROUGH NORTH
CENTRAL MONTANA AND SOUTHERN ALBERTA. MODELS CONTINUE TO BE IN
GOOD AGREEMENT BRINGING THE TROUGH SOUTH WITH WINDS SHIFTING TO
THE NORTH AS A CANADIAN COLD FRONT PUSHES INTO MONTANA. THIS
SOLUTION REMAINS ON TRACK AS SURFACE OBSERVATIONS SHOW THAT THE
COLD FRONT HAS ALREADY PUSHED INTO THE LETHBRIDGE AREA. THIS
FRONT WILL CONTINUE PUSHING INTO MY FORECAST AREA OVERNIGHT WITH
SCATTERED PRECIPITATION DEVELOPING ACROSS MY NORTHEAST ZONES
DURING THE EVENING THEN BECOMING MORE WIDESPREAD ALONG A
CONVERGENCE BOUNDARY THAT SHOULD SET UP ALONG A LINE FROM NEAR
HAVRE TO LEWISTOWN. IT APPEARS THAT SNOW WILL BECOME LIKELY ACROSS
ALL EASTERN PORTIONS OF NORTH CENTRAL MONTANA BY MORNING WITH SNOW
GRADUALLY TAPERING OFF FROM NORTHWEST TO SOUTHEAST DURING THE
AFTERNOON. AM EXPECTING 12 TO 18 HOUR SNOW TOTALS OF 2 TO 5 INCHES
IN THIS AREA SO WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY
FOR SNOW. AT THIS TIME IT DOES NOT APPEAR THAT THE GREAT FALLS
AREA WILL RECEIVE MORE THAN A CHANCE OF SNOW WITH PERHAPS AN INCH
OR SO OF ACCUMULATION. HOWEVER...THERE IS A DANGER THAT THE MODELS
HAVE THE BOUNDARY LOCATED TOO FAR TO THE EAST. IF SO...THERE IS A
POSSIBILITY THAT OVERNIGHT SHIFTS MAY DRASTICALLY INCREASE POPS
AND SNOW AMOUNTS FOR CENTRAL AND WESTERN PORTIONS OF NORTH CENTRAL
MONTANA. RESIDUAL SNOW SHOWERS WILL LINGER ACROSS THE EASTERN
PLAINS WEDNESDAY EVENING BUT SHOULD DIMINISH OVERNIGHT AS THE
CANADIAN AIRMASS SLIDES EAST. BY THURSDAY THE UPPER LEVEL RIDGE
OVER THE WEST COAST SHOULD BEGIN TO EDGE INTO THE NORTHERN ROCKY
MOUNTAIN REGION ALLOWING TEMPERATURES TO INCREASE ONCE AGAIN AS
DOWNSLOPE WINDS REASSERT THEMSELVES AND CLEARING SKIES MOVE INTO
CENTRAL MONTANA. MPJ
THURSDAY NIGHT THROUGH SUNDAY NIGHT. MODELS MAINTAINED GOOD
AGREEMENT ON DEVELOPMENT OF A BROAD AND WELL-AMPLIFIED PACIFIC UPPER
RIDGE THAT WILL DOMINATE THE WEATHER ACROSS THE WESTERN US AND SW
CANADA FOR THE LATTER HALF OF THIS WEEK. THIS WILL LEAD TO SEVERAL
DAYS OF DRY CONDITIONS WITH MAX TEMPERATURES OF 10 TO POSSIBLY AS
HIGH AS 20 DEG ABOVE NORMAL ACROSS ALL ZONES BY SUNDAY. MODELS
STILL DEPICT A COUPLE OF SHORTWAVE TROFS COMING OVER THE TOP OF THE
RIDGE DURING THIS PERIOD BUT THEY ARE NOW SHOWN FURTHER EAST AND
CONSIDERABLY DRIER THAT YESTERDAYS MODEL RUNS...SO HAVE REDUCED SKY
COVER GRIDS DOWN TO MOSTLY CLEAR SKIES THRU SUNDAY. THIS WILL ALLOW
NIGHTTIME TEMPS TO DROP BACK BELOW FREEZING EACH NIGHT SO REFREEZING
OF MELTED SNOW/ICE WILL BE A CONCERN DURING THE MORNING HOURS.
WARANAUSKAS
MONDAY AND TUESDAY...LATEST MODELS DEPICT A HIGH PRESSURE RIDGE
OVER THE WESTERN STATES MONDAY. BY TUESDAY AFTERNOON THE RIDGE IS
EXPECTED TO MOVE SOUTH AS AN APPROACHING LOW PRESSURE TROUGH MOVES
INTO THE PACIFIC NORTHWEST. TEMPERATURES WILL BE ABOVE SEASONAL
AVERAGES FOR MUCH OF THE REGION. SAUCIER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 23 30 23 45 / 60 70 10 0
CTB 20 30 23 45 / 20 20 10 0
HLN 31 36 23 44 / 10 10 10 0
BZN 28 38 20 44 / 10 20 10 0
WEY 15 30 11 31 / 20 20 20 10
DLN 20 34 18 42 / 0 10 10 0
HVR 3 10 5 33 / 60 60 30 10
LWT 18 25 18 42 / 70 70 40 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MST WEDNESDAY FOR MTZ011-013-
047-050-051.
&&
$$
SHORT TERM...BLANK
LONG TERM...EMANUEL
AVIATION...EMANUEL
WEATHER.GOV/GREATFALLS
000
FXUS65 KBYZ 140401
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
901 PM MST TUE JAN 13 2009
.SHORT TERM...VALID FOR WED AND THU...
UPDATE FOR ZONES TONIGHT NO UPDATE FOR AFP. INVERTED SURFACE
TROUGH HAS SET UP OVER SOUTHERN MONTANA THIS EVENING AND WAS
LOCATED FROM SOUTHEAST MONTANA NEAR ALZADA...WEST NORTHWEST TO
BOZEMAN. STRONG COLD FRONT ALSO BACKING INTO THE AREA FROM THE
NORTHEAST AND WAS LOCATED FROM BAKER NORTHWEST THROUGH MALTA AT
03Z. VERY COLD AIR WAS LOCATED BEHIND THE FRONT OVER SOUTHERN
SASKATCHEWAN AND WILL FILTER SOUTH OVERNIGHT. MODELS NOT DOING A
VERY GOOD JOB IN HANDLING THIS COLD AIR PUSHING INTO THE REGION
AND HAVE LOWERED TEMPERATURES FROM BILLINGS EAST TONIGHT. WINTER
WEATHER ADVISORY STILL ON TRACK FOR TOMORROW AS STRONG SURFACE
CONVERGENCE WILL SET UP ALONG THE INVERTED TROUGH ALONG WITH A
MOIST AND UNSTABLE NORTHWEST FLOW OVER THE REGION WEDNESDAY. DID
INCREASE POPS FURTHER WEST TONIGHT WITH PUSH OF COLD AIR BUT MAIN
SNOW FALL WILL REMAIN OVER SOUTH CENTRAL MONTANA. RICHMOND
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MODELS REMAIN CONSISTENT WITH BUILDING RIDGE INTO THE AREA FOR
LATE WEEK INTO EARLY NEXT WEEK. THIS WILL BRING MUCH ABOVE
TEMPERATURES ALONG WITH DRY CONDITIONS. INCREASED HIGH
TEMPERATURES A FEW DEGREES TO STAY ABOVE GUIDANCE WHICH TENDS TO
UNDER DO TEMPERATURES HEADING INTO A STRONG RIDGE. A WEAK
DISTURBANCE WILL DROP THROUGH THE AREA LATE FRIDAY NIGHT INTO
SATURDAY MORNING...BUT THE FAST MOVEMENT OF THE SYSTEM AND LACK
OF SIGNIFICANT MOISTURE POINTS TO ONLY A SLIGHT CHANCE OF SNOW
SHOWERS OVER EASTERN ZONES DURING THIS TIME FRAME. MODELS HAVE
ALSO BEEN CONSISTENT WITH ADVERTISING A RETURN TO WINTER
CONDITIONS TUESDAY INTO WEDNESDAY AS A CHUNK OF ARCTIC AIR SLIDES
SOUTHWARD. CERTAINLY TIME FOR IDEAS TO CHANGE OUT THAT FAR BUT
HAVE TRENDED TEMPERATURES DOWN BY DAY 8. CHAMBERS
&&
.AVIATION...
SCATTERED RAIN/SNOW SHOWERS WILL BE POSSIBLE ACROSS THE REGION
FOR THE OVERNIGHT PERIOD. BRIEF PERIODS OF MVFR CONDITIONS MAY
ACCOMPANY THIS LIGHT PRECIPITATION. MOUNTAIN PEAKS MAY BECOME
OBSCURED AS PRECIPITATION MOVES ACROSS THE HIGHER TERRAIN. A COLD
FRONT WILL PUSH INTO THE REGION TOWARD SUNRISE AND BRING A
GREATER CHANCE FOR SNOW. THE HEAVIEST AMOUNTS OF SNOW WILL LIKELY
BE ALONG UPSLOPE REGIONS OF THE BEARTOOTH AND BIG HORN MOUNTAINS.
SNOWFALL WILL ALSO BE HEAVIER ACROSS CENTRAL ZONES...INCLUDING
KBIL...WEDNESDAY MORNING THROUGH THE AFTERNOON.
SCHUKNECHT/RICHMOND
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 019/027 017/037 027/048 035/050 032/052 036/050 038/044
78/S 70/B 00/N 00/U 00/U 00/U 00/U
LVM 029/035 025/045 034/051 038/051 030/052 035/050 034/044
13/S 20/B 00/N 00/U 00/U 00/U 00/U
HDN 018/026 008/034 023/046 029/049 029/052 029/051 028/046
88/S 70/B 00/U 00/U 00/U 00/U 00/U
MLS 005/008 903/021 012/042 027/043 022/048 027/046 026/041
76/S 41/B 00/U 22/S 00/U 00/U 00/U
4BQ 010/015 901/029 019/052 030/051 026/051 028/051 029/046
78/S 63/S 00/U 22/S 00/U 00/U 00/U
BHK 903/000 908/019 010/046 022/044 020/046 023/045 020/040
62/S 11/B 10/U 22/S 00/U 00/U 00/U
SHR 021/027 014/037 024/053 026/050 025/052 026/049 030/047
89/S 72/O 00/U 00/U 00/U 00/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 6 AM WEDNESDAY TO 6 AM
MST THURSDAY FOR ZONES 29-35-38-57.
WINTER WEATHER ADVISORY IN EFFECT FROM 3 AM WEDNESDAY TO 3 AM
MST THURSDAY FOR ZONES 30-31-36-58.
WY...WINTER WEATHER ADVISORY IN EFFECT FROM 6 AM WEDNESDAY TO 6 AM
MST THURSDAY FOR ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
000
FXUS65 KGGW 140339
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
839 PM MST TUE JAN 13 2009
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
GOING FORECAST HAD TO BE UPDATED SEVERAL TIMES SO FAR. CLIPPER
SYSTEM EXITING THE AREA WITH NO HARD FEELINGS. HIGH WINDS THAT
OCCURRED LATE THIS AFTERNOON HAVE DIMINISHED. THIS IS THE SECOND
TIME THAT THIS KIND OF SET UP HAS OCCURRED THIS WEEK WHERE WINDS
HAVE MIXED DOWN FROM THE MID LEVELS AND ARE STRONGER THAN EXPECTED.
ALL HIGH WIND WARNINGS HAVE BEEN CANCELLED. ARCTIC FRONT NOW
SUPRESSING THAT AND HAS BECOME DIFFUSED WHILE MUCH COLDER AIR POURS
IN FROM CANADA. RAISED POPS IN THE SW ZONES AS BAND OF SNOW MOVING
SOUTH INTO THAT AREA. LOOKING FOR VERY LITTLE SNOW WILL THIS (INCH
OR LESS). UPDATED PRODUCTS HAVE BEEN ISSUED. JAMBA
PREVIOUS DISCUSSION...
SURFACE LOW MOVING INTO WESTERN NORTH DAKOTA WITH FRONT TRAILING
BACK INTO SOUTHWEST SASKATCHEWAN. VERY STRONG WINDS HAVE DEVELOPED
SOUTHWEST OF THIS FRONT...MIXING VERY WARM AIR TO THE SURFACE.
WINDS HAVE CREATED OCCASIONAL WHITEOUT CONDITIONS ACROSS THE
NORTHEAST ZONES...WHERE THERE HAS NOT BEEN AS MUCH ICE...AND SNOW
IS LOOSER. THUS HAVE ISSUED A WINTER WEATHER ADVISORY FOR
BLOWING SNOW FOR THE EVENING OVER THE FAR NORTHEAST.
FRONT WILL SAG SOUTHWARD OVERNIGHT...USHERING ARCTIC AIR BACK INTO
NORTHEAST MONTANA. WINDS WILL DIMINISH OVERNIGHT AS LOW LEVEL JET
MOVES SOUTHEAST...BUT COLD AIR ADVECTION SUBSIDENCE WILL MAKE THIS
SLOW. AS TEMPERATURES DROP TO NEAR OR BELOW ZERO...BREEZY
CONDITIONS WILL LEAD TO WIND CHILLS BELOW MINUS 20. HAVE ISSUED
WIND CHILL WARNING FOR LATE TONIGHT THROUGH WEDNESDAY MORNING FOR
THE LOW WIND CHILLS.
FRONT EXPECTED TO HANGUP ACROSS CENTRAL MONTANA ON WEDNESDAY AS
HIGH PRESSURE DROPS INTO THE DAKOTAS. EXPECT SOME PRECIPITATION IN
THE CHANNELED VORTICITY ALONG THIS BOUNDARY...BUT WILL BE
GENERALLY LIGHT. OVERALL EXPECT 2 TO 4 INCHES OF SNOW FROM EARLY
WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT. HEAVIEST AMOUNTS
WILL BE IN THE LITTLE ROCKIES.
FRONT LIFTS BACK TO THE NORTHEAST ON THURSDAY WITH HIGH PRESSURE
MOVING OFF THE SOUTHEAST. UPPER RIDGE OVER THE WEST COAST BEGINS
PUSHING WARM AIR ACROSS THE DIVIDE AND OVER THE ARCTIC AIRMASS IN
EASTERN MONTANA. EBERT
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
SOLID OPERATIONAL MODEL AND ENSEMBLE AGREEMENT CONTINUES THROUGH
EARLY NEXT WEEK. A LARGE UPPER LEVEL RIDGE IS EXPECTED TO MOVE
OVER THE WESTERN UNITED STATES THIS WEEKEND BRINGING WELL ABOVE
NORMAL TEMPERATURES. UPPER HEIGHTS BEGIN TO FALL EARLY NEXT WEEK
IN RESPONSE TO A DIGGING TROUGH MOVING FROM THE GULF OF ALASKA
INTO WESTERN CANADA. NONETHELESS...1000-500MB THICKNESS VALUES
REMAIN IN EXCESS OF 550DAM...SO TEMPERATURES WILL CONTINUE TO BE
WELL ABOVE AVERAGE. 12Z GFS AND ECMWF BOTH INDICATE THAT THE
AFOREMENTIONED TROUGH WILL CONTINUE TO DIG SOUTHEAST AND PUSH A
COLD FRONT THROUGH THE AREA BY THE MIDDLE OF NEXT WEEK...BUT
TIMING AND STRENGTH ISSUES EXIST.
THE MAIN CHANGE TO THE EXTENDED FORECAST WAS TO TREND TEMPERATURES
UPWARD FRIDAY...SUNDAY...AND MONDAY. ESPECIALLY OVER THE
SOUTHWESTERN PORTION OF THE CWA WHERE SNOW COVER IS LITTLE TO NON-
EXISTENT. THE REASONING FRIDAY IS THE PASSAGE OF A SHORTWAVE
TROUGH...WHICH SHOULD ENHANCE MIXING....AND THEN THE UPPER RIDGE
EXERTS ITSELF SUNDAY AND MONDAY. OTHERWISE...ONLY A FEW MINOR
ADJUSTMENTS FOR COORDINATION PURPOSES. AJZ
PREVIOUS LONG TERM DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT FOR THE MOST PART THRU THE
EXTENDED PERIOD. IT APPEARS THAT THE END OF THIS WEEK THRU EARLY
NEXT WEEK WILL BE ONE OF THE NICEST STRETCHES WE HAVE HAD FOR SOME
TIME AS WE WILL BE UNDER THE EFFECTS A BIG UPPER RIDGE. THE
BEGINNING OF THE PERIOD ON THURSDAY NIGHT HAS THE WESTERN UPPER
RIDGE AXIS FAR ENUF EAST TO PUSH THE ARCTIC AIR INTO THE DAKOTAS
AND GIVE US 850 MB TEMPERATURES ABOVE ZERO CELSIUS. THE WARM AIR
ADVECTION THEN CONTINUES THRU THE WEEKEND AND EARLY NEXT WEEK AS
THE RIDGE AXIS MOVES EAST. ONLY REAL WRINKLE AMONGST THE MODELS IS
THE HANDLING OF A FAST-MOVING UPPER DISTURBANCE IN THE NORTHWEST
FLOW FRIDAY NIGHT INTO SATURDAY. OPERATIONAL GFS IS THE ODD MODEL
OUT WITH THIS FEATURE WITH RESPECT TO IT BEING MOIST ENUF HERE TO
GENERATE SOME LIGHT PRECIPITATION AS IT MOVES DIRECTLY OVERHEAD.
REMAINING OPERATIONAL MODELS TAKE THIS FEATURE FARTHER EAST INTO
THE DAKOTAS AND LEAVE THE LOWER LEVELS OF THE ATMOSPHERE HERE ON
THE DRY SIDE. SO FOR NOW WILL KEEP THINGS DRY AND SIMPLY ADD IN
SOME CLOUDS TO ACCOUNT FOR THE PASSAGE OF THIS WAVE. OTHERWISE NOT
EXPECTING MUCH IN THE WAY OF CLOUDS THRU MOST OF THE EXTENDED
PERIOD. TEMPERATURES WILL DEFINITELY BE WARMER THAN WE HAVE HAD
FOR SOME TIME. BIG QUESTION IS THE AMOUNT OF MIXING TO GET THE
WARM AIR DOWN TO THE SURFACE...AS OTHERWISE THE SNOW COVER WILL
AID IN KEEPING TEMPERATURES ON THE COOL SIDE DESPITE THE MILD AIR
ALOFT. FOR NOW WILL KEEP THE WARMING TEMPERED...ESPECIALLY AT
NIGHT AND FOR THE NORTHEAST HALF OR SO OF THE CWA. BUT IT WILL
STILL BE RELATIVELY MILD NONETHELESS. AS THE WEEK UNFOLDS
EXPECTING THAT A BETTER DETERMINATION OF EXPECTED WIND AND MIXING
CAN BE MADE.
&&
.AVIATION...
MVFR OVERCAST CEILINGS AROUND 25 HUNDRED FT THRU THE REST OF THE
NIGHT AND WED MORN. LIGHT SHOW ACROSS THE SW THIRD OF THE
FORECAST AREA...PETROELUEM....GARFIELD...SOUTH AND SOUTHWEST
PHILLIPS COUNTIES WILL ALSO REDUCE VISIBILITIES TO MVFR 3-5 MILES
THE REST OF THE NIGHT AND WED MORN. CLEARING SKIES FROM THE NORTH
WILL REACH TO NORTH OF A ROUGHLY OPHEIM TO SIDNEY LINE BY NOON.
THIS INDLUDES SHERIDAN...DANIELS...AND ROOSEVELT COUNTIES.
SIMONSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR DANIELS-
SHERIDAN-WESTERN ROOSEVELT-RICHLAND-NORTHERN VALLEY-EASTERN
ROOSEVELT.
WIND CHILL ADVISORY UNTIL 10 AM MST WEDNESDAY FOR CENTRAL AND
SOUTHERN VALLEY-DANIELS-SHERIDAN-WESTERN ROOSEVELT-MCCONE-
RICHLAND-DAWSON-WIBAUX-NORTHERN PHILLIPS-NORTHERN VALLEY-EASTERN
ROOSEVELT.
&&
$$
WEATHER.GOV/GLASGOW
000
FXUS65 KBYZ 140120
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
620 PM MST TUE JAN 13 2009
.SHORT TERM...VALID FOR WED AND THU...
UPDATE THIS EVENING TO INCREASE WINDS IN THE BAKER AREA THROUGH
06Z. STRONG PRESSURE RISES MOVING FROM NORTHEAST MONTANA INTO
WESTERN NORTH DAKOTA WILL BRING STRONG WINDS THROUGH THE EVENING
FOR BAKER. HAVE KEPT WINDS JUST BELOW WARNING CRITERIA WITH COLD
FRONT EXPECTED TO PUSH THROUGH THE AREA AROUND 03Z. ALSO
INCREASED WINDS OVER LIVINGSTON AS THEY WILL CONTINUE TO BE GUSTY
FOR SEVERAL MORE HOURS. REMAINDER OF FORECAST ON TRACK AND NO
OTHER CHANGES AT THIS TIME. WILL MAKE ANOTHER UPDATE AROUND 9 PM
WHEN 00Z MODEL RUN COMES IN. RICHMOND
PREVIOUS DISCUSSION...
STRONG NORTHWEST FLOW ALOFT OVER EASTERN MONTANA WITH ARCTIC AIR
HAVING RETREATED OUT OF THE REGION THIS AFTERNOON. UPPER LEVEL
RIDGE ALONG THE WEST COAST IS PROGGED TO STRENGTHEN DURING THE
NEXT 36 HOURS AND MOVE EASTWARD ALLOWING THE FLOW ALOFT TO TURN
MORE NORTHERLY. THIS WILL ALLOW A SURGE OF ARCTIC AIR BACK INTO
THE AREA WHICH IS EXPECTED TO BRING A SNOW EVENT TO THE CENTRAL
ZONES. FOR LATE THIS AFTERNOON A WELL MIXED ATMOSPHERE IS
SUPPORTING TEMPERATURES IN THE 40S AND 50S AND ALLOWING SOME OF
THE NORTHWEST FLOW TO MIX DOWN. SURFACE LOW PRESSURE OVER EASTERN
MONTANA IS MOVING SOUTHEASTWARD INTO SOUTH DAKOTA AND THIS IS
DECREASING PRESSURE GRADIENTS AND ALLOWED WIND ADVISORY FOR THE
LIVINGSTON AREA TO EXPIRE. A STRONG COLD FRONT WILL ROTATE BACK
INTO THE STATE BEHIND THIS SURFACE LOW BUT TIMING ON THIS FEATURE
IS DIFFICULT SINCE WARM AIR INTRUDED A LITTLE FURTHER EASTWARD
THAN PREVIOUSLY PROGGED. EXPECT THE FRONT TO MOVE INTO THE AREA
FROM NORTHEAST TO THE SOUTHWEST PASSING KBHK AROUND 00Z AND
REACHING KBIL AROUND 08Z. THIS BOUNDARY BEGINS TO STALL OUT AS
HEADS FURTHER WEST AS SURFACE HIGH PRESSURE OVER IDAHO MAINTAINS
A LOW LEVEL WEST SOUTHWEST FLOW OVER THE MOUNTAINS. WHERE THE
BOUNDARY SETS UP WILL PRIME AN AREA FOR A LONG DURATION LIGHT
SNOWFALL WITH LOW LEVEL CONVERGENCE PROVIDING MOST OF THE LIFT.
EAST OF THIS ZONE INCLUDING MILES CITY AND PARTS EAST AND SOUTH
COLD AIR WILL BE PRETTY DEEP SO EXPECT SNOW TO NOT ACCUMULATE
VERY MUCH. WEST AND SOUTH OF COLUMBUS COLD AIR IS NOT EXPECTED TO
BECOME DOMINANT AND ANTICIPATE THAT TEMPERATURES MAY NOT
EXPERIENCE THE PLUNGE THAT WILL OCCUR FROM BILLINGS EASTWARD.
EXPECT THE SNOW TO CONTINUE WEDNESDAY NIGHT IN THE SAME AREAS
WITH MODELS HINTING AS SOME WARM AIR LIFT ALOFT OCCURRING LATE
WEDNESDAY BUT FORCING STILL LOOKS WEAK.
ON THURSDAY HEIGHTS BEGIN RISING OVER THE AREA AND EXPECT MID
LEVEL WARM AIR ADVECTION WILL ALLOW SOME LIGHT SNOW TO FALL BUT
WEAKER SURFACE FLOW WILL LIMIT ANY UPSLOPE FACTOR. AS THE ARCTIC
AIR RETREATS TO THE EAST THIS WILL ALLOW FOR A SLIGHT MODERATION
IN TEMPERATURES AND LEESIDE TROUGHING IS EXPECTED TO FORM LATE IN
THE AFTERNOON OR EARLY EVENING. WITH STRONG SURFACE PRESSURES
REMAINING STAGNANT OVER SOUTHEAST IDAHO GAP FLOW WINDS SHOULD BE
ON THE INCREASE THURSDAY NIGHT BUT GRADIENTS ONLY PROGGED TO REACH
10 TO 20 MB AT THIS TIME SO MAY NOT NEED A WIND ADVISORY FOR GAP
FLOW AREAS QUITE YET.
BORSUM
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MODELS REMAIN CONSISTENT WITH BUILDING RIDGE INTO THE AREA FOR
LATE WEEK INTO EARLY NEXT WEEK. THIS WILL BRING MUCH ABOVE
TEMPERATURES ALONG WITH DRY CONDITIONS. INCREASED HIGH
TEMPERATURES A FEW DEGREES TO STAY ABOVE GUIDANCE WHICH TENDS TO
UNDER DO TEMPERATURES HEADING INTO A STRONG RIDGE. A WEAK
DISTURBANCE WILL DROP THROUGH THE AREA LATE FRIDAY NIGHT INTO
SATURDAY MORNING...BUT THE FAST MOVEMENT OF THE SYSTEM AND LACK
OF SIGNIFICANT MOISTURE POINTS TO ONLY A SLIGHT CHANCE OF SNOW
SHOWERS OVER EASTERN ZONES DURING THIS TIME FRAME. MODELS HAVE
ALSO BEEN CONSISTENT WITH ADVERTISING A RETURN TO WINTER
CONDITIONS TUESDAY INTO WEDNESDAY AS A CHUNK OF ARCTIC AIR SLIDES
SOUTHWARD. CERTAINLY TIME FOR IDEAS TO CHANGE OUT THAT FAR BUT
HAVE TRENDED TEMPERATURES DOWN BY DAY 8. CHAMBERS
&&
.AVIATION...
WINDY CONDITIONS WILL PERSIST THROUGH THE EARLY EVENING BEFORE
DIMINISHING LATE TONIGHT. A FEW LIGHT SHOWERS WILL CONTINUE TO
STREAM ACROSS EASTERN ZONES FROM TIME TO TIME...BUT VFR
CONDITIONS SHOULD PREVAIL. LATE TONIGHT A COLD FRONT WILL PRESS
INTO THE EASTERN PORTION OF THE FORECAST AREA...AND INTO CENTRAL
AREAS AROUND DAWN. WINDS WILL INCREASE IN THE SHERIDAN AREA A FEW
HOURS AHEAD OF THE FRONT WITH PERIODIC GUSTS OF 35 TO 50 MPH
POSSIBLE. BEHIND THE FRONT NORTHEAST WINDS WILL BRING PERIODS OF
SNOW AND IFR CEILINGS AND VISIBILITIES. IT APPEARS HEAVIER SNOW
WILL STAY EAST OF A RED LODGE TO HARLOWTON LINE WITH THIS SYSTEM.
EXPECT OCCASIONAL MOUNTAIN OBSCURATION FOR THE WESTERN MOUNTAINS
BY MORNING...WITH TOTAL OBSCURATION FOR THE BIG HORN MOUNTAINS BY
LATE TONIGHT.
FOR EARLY WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON...A
CORRIDOR OF MODERATE TO HEAVY SNOW IS EXPECTED TO DEVELOP FROM
ROUNDUP TO BILLINGS TO SHERIDAN. WITHIN 50NM EITHER SIDE OF THIS
LINE EXPECT VISIBILITIES BELOW 1/2SM AT TIMES IN MODERATE TO
OCCASIONALLY HEAVY SNOW AND CEILINGS UNDER 500 FEET. THESE
CONDITIONS MAY PERSIST INTO WEDNESDAY NIGHT AS THE COLD FRONT
BECOMES STATIONARY AND THEN SHIFTS EASTWARD AS A WARM FRONT.
CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 026/027 017/037 027/048 035/050 032/052 036/050 038/044
78/S 70/B 00/N 00/U 00/U 00/U 00/U
LVM 029/035 025/045 034/051 038/051 030/052 035/050 034/044
13/S 20/B 00/N 00/U 00/U 00/U 00/U
HDN 021/026 008/034 023/046 029/049 029/052 029/051 028/046
88/S 70/B 00/U 00/U 00/U 00/U 00/U
MLS 007/008 903/021 012/042 027/043 022/048 027/046 026/041
75/S 41/B 00/U 22/S 00/U 00/U 00/U
4BQ 012/015 901/029 019/052 030/051 026/051 028/051 029/046
77/S 63/S 00/U 22/S 00/U 00/U 00/U
BHK 902/000 908/019 010/046 022/044 020/046 023/045 020/040
62/S 11/B 10/U 22/S 00/U 00/U 00/U
SHR 023/027 014/037 024/053 026/050 025/052 026/049 030/047
89/S 72/O 00/U 00/U 00/U 00/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 6 AM WEDNESDAY TO 6 AM
MST THURSDAY FOR ZONES 29-35-38-57.
WINTER WEATHER ADVISORY IN EFFECT FROM 3 AM WEDNESDAY TO 3 AM
MST THURSDAY FOR ZONES 30-31-36-58.
WY...WINTER WEATHER ADVISORY IN EFFECT FROM 6 AM WEDNESDAY TO 6 AM
MST THURSDAY FOR ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
000
FXUS65 KTFX 132345
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
435 PM MST TUE JAN 13 2009
UPDATED AVIATION SECTION
.DISCUSSION...
TONIGHT THROUGH THURSDAY...SURFACE LOW PRESSURE SYSTEM CONTINUES
TO ACCELERATE AWAY FROM MONTANA THIS AFTERNOON. AN INVERTED LOW
PRESSURE TROUGH EXTENDS NORTHWEST FROM THIS SYSTEM THROUGH NORTH
CENTRAL MONTANA AND SOUTHERN ALBERTA. MODELS CONTINUE TO BE IN
GOOD AGREEMENT BRINGING THE TROUGH SOUTH WITH WINDS SHIFTING TO
THE NORTH AS A CANADIAN COLD FRONT PUSHES INTO MONTANA. THIS
SOLUTION REMAINS ON TRACK AS SURFACE OBSERVATIONS SHOW THAT THE
COLD FRONT HAS ALREADY PUSHED INTO THE LETHBRIDGE AREA. THIS
FRONT WILL CONTINUE PUSHING INTO MY FORECAST AREA OVERNIGHT WITH
SCATTERED PRECIPITATION DEVELOPING ACROSS MY NORTHEAST ZONES
DURING THE EVENING THEN BECOMING MORE WIDESPREAD ALONG A
CONVERGENCE BOUNDARY THAT SHOULD SET UP ALONG A LINE FROM NEAR
HAVRE TO LEWISTOWN. IT APPEARS THAT SNOW WILL BECOME LIKELY ACROSS
ALL EASTERN PORTIONS OF NORTH CENTRAL MONTANA BY MORNING WITH SNOW
GRADUALLY TAPERING OFF FROM NORTHWEST TO SOUTHEAST DURING THE
AFTERNOON. AM EXPECTING 12 TO 18 HOUR SNOW TOTALS OF 2 TO 5 INCHES
IN THIS AREA SO WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY
FOR SNOW. AT THIS TIME IT DOES NOT APPEAR THAT THE GREAT FALLS
AREA WILL RECEIVE MORE THAN A CHANCE OF SNOW WITH PERHAPS AN INCH
OR SO OF ACCUMULATION. HOWEVER...THERE IS A DANGER THAT THE MODELS
HAVE THE BOUNDARY LOCATED TOO FAR TO THE EAST. IF SO...THERE IS A
POSSIBILITY THAT OVERNIGHT SHIFTS MAY DRASTICALLY INCREASE POPS
AND SNOW AMOUNTS FOR CENTRAL AND WESTERN PORTIONS OF NORTH CENTRAL
MONTANA. RESIDUAL SNOW SHOWERS WILL LINGER ACROSS THE EASTERN
PLAINS WEDNESDAY EVENING BUT SHOULD DIMINISH OVERNIGHT AS THE
CANADIAN AIRMASS SLIDES EAST. BY THURSDAY THE UPPER LEVEL RIDGE
OVER THE WEST COAST SHOULD BEGIN TO EDGE INTO THE NORTHERN ROCKY
MOUNTAIN REGION ALLOWING TEMPERATURES TO INCREASE ONCE AGAIN AS
DOWNSLOPE WINDS REASSERT THEMSELVES AND CLEARING SKIES MOVE INTO
CENTRAL MONTANA. MPJ
THURSDAY NIGHT THROUGH SUNDAY NIGHT. MODELS MAINTAINED GOOD
AGREEMENT ON DEVELOPMENT OF A BROAD AND WELL-AMPLIFIED PACIFIC UPPER
RIDGE THAT WILL DOMINATE THE WEATHER ACROSS THE WESTERN US AND SW
CANADA FOR THE LATTER HALF OF THIS WEEK. THIS WILL LEAD TO SEVERAL
DAYS OF DRY CONDITIONS WITH MAX TEMPERATURES OF 10 TO POSSIBLY AS
HIGH AS 20 DEG ABOVE NORMAL ACROSS ALL ZONES BY SUNDAY. MODELS
STILL DEPICT A COUPLE OF SHORTWAVE TROFS COMING OVER THE TOP OF THE
RIDGE DURING THIS PERIOD BUT THEY ARE NOW SHOWN FURTHER EAST AND
CONSIDERABLY DRIER THAT YESTERDAYS MODEL RUNS...SO HAVE REDUCED SKY
COVER GRIDS DOWN TO MOSTLY CLEAR SKIES THRU SUNDAY. THIS WILL ALLOW
NIGHTTIME TEMPS TO DROP BACK BELOW FREEZING EACH NIGHT SO REFREEZING
OF MELTED SNOW/ICE WILL BE A CONCERN DURING THE MORNING HOURS.
WARANAUSKAS
MONDAY AND TUESDAY...LATEST MODELS DEPICT A HIGH PRESSURE RIDGE
OVER THE WESTERN STATES MONDAY. BY TUESDAY AFTERNOON THE RIDGE IS
EXPECTED TO MOVE SOUTH AS AN APPROACHING LOW PRESSURE TROUGH MOVES
INTO THE PACIFIC NORTHWEST. TEMPERATURES WILL BE ABOVE SEASONAL
AVERAGES FOR MUCH OF THE REGION. SAUCIER
&&
.AVIATION...
UPDATED 2335Z.
MOIST NORTHWEST FLOW ALOFT WILL PERSIST. A SURFACE FRONTAL BOUNDARY
OVER NORTHEAST MONTANA WILL CONTINUE TO SLIDE SOUTH AND
WEST...REACHING A KCTB TO KBIL LINE BY WEDNESDAY MORNING. LIGHT SNOW
AND LOWERING CEILINGS CAN BE EXPECTED NORTH AND EAST OF THIS LINE.
VFR CONDITIONS WILL PREVAIL THIS EVENING BUT BECOME MVFR/IFR NORTH
AND EAST OF THE FRONTAL BOUNDARY AFTER 04Z DUE TO LOW CEILINGS AND
SNOW. KHVR AND KLWT WILL LIKELY EXPERIENCE THE GREATEST IMPACT AS
THEY WILL BE IN THE COLD SECTOR OF THE FRONT AND REMAIN THERE
THROUGH WEDNESDAY MORNING. HIGHER TERRAIN WILL BECOME OBSCURED NORTH
AND EAST OF THE AFOREMENTIONED LINE AFTER 04Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 23 30 23 45 / 20 40 10 0
CTB 20 30 23 45 / 20 20 10 0
HLN 27 36 23 44 / 10 10 10 0
BZN 24 38 20 44 / 10 20 10 0
WEY 15 30 11 31 / 20 20 20 10
DLN 20 34 18 42 / 0 10 10 0
HVR 3 10 5 33 / 60 60 30 10
LWT 18 25 18 42 / 60 70 40 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MST
WEDNESDAY FOR MTZ011-013-047-050-051.
&&
$$
SHORT TERM...MPJ
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...EMANUEL
WEATHER.GOV/GREATFALLS
000
FXUS65 KBYZ 132244
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
344 PM MST TUE JAN 13 2009
.SHORT TERM...VALID FOR WED AND THU...
STRONG NORTHWEST FLOW ALOFT OVER EASTERN MONTANA WITH ARCTIC AIR
HAVING RETREATED OUT OF THE REGION THIS AFTERNOON. UPPER LEVEL
RIDGE ALONG THE WEST COAST IS PROGGED TO STRENGTHEN DURING THE
NEXT 36 HOURS AND MOVE EASTWARD ALLOWING THE FLOW ALOFT TO TURN
MORE NORTHERLY. THIS WILL ALLOW A SURGE OF ARCTIC AIR BACK INTO
THE AREA WHICH IS EXPECTED TO BRING A SNOW EVENT TO THE CENTRAL
ZONES. FOR LATE THIS AFTERNOON A WELL MIXED ATMOSPHERE IS
SUPPORTING TEMPERATURES IN THE 40S AND 50S AND ALLOWING SOME OF
THE NORTHWEST FLOW TO MIX DOWN. SURFACE LOW PRESSURE OVER EASTERN
MONTANA IS MOVING SOUTHEASTWARD INTO SOUTH DAKOTA AND THIS IS
DECREASING PRESSURE GRADIENTS AND ALLOWED WIND ADVISORY FOR THE
LIVINGSTON AREA TO EXPIRE. A STRONG COLD FRONT WILL ROTATE BACK
INTO THE STATE BEHIND THIS SURFACE LOW BUT TIMING ON THIS FEATURE
IS DIFFICULT SINCE WARM AIR INTRUDED A LITTLE FURTHER EASTWARD
THAN PREVIOUSLY PROGGED. EXPECT THE FRONT TO MOVE INTO THE AREA
FROM NORTHEAST TO THE SOUTHWEST PASSING KBHK AROUND 00Z AND
REACHING KBIL AROUND 08Z. THIS BOUNDARY BEGINS TO STALL OUT AS
HEADS FURTHER WEST AS SURFACE HIGH PRESSURE OVER IDAHO MAINTAINS A
LOW LEVEL WEST SOUTHWEST FLOW OVER THE MOUNTAINS. WHERE THE
BOUNDARY SETS UP WILL PRIME AN AREA FOR A LONG DURATION LIGHT
SNOWFALL WITH LOW LEVEL CONVERGENCE PROVIDING MOST OF THE LIFT.
EAST OF THIS ZONE INCLUDING MILES CITY AND PARTS EAST AND SOUTH
COLD AIR WILL BE PRETTY DEEP SO EXPECT SNOW TO NOT ACCUMULATE VERY
MUCH. WEST AND SOUTH OF COLUMBUS COLD AIR IS NOT EXPECTED TO
BECOME DOMINANT AND ANTICIPATE THAT TEMPERATURES MAY NOT
EXPERIENCE THE PLUNGE THAT WILL OCCUR FROM BILLINGS EASTWARD.
EXPECT THE SNOW TO CONTINUE WEDNESDAY NIGHT IN THE SAME AREAS WITH
MODELS HINTING AS SOME WARM AIR LIFT ALOFT OCCURRING LATE WEDNESDAY
BUT FORCING STILL LOOKS WEAK.
ON THURSDAY HEIGHTS BEGIN RISING OVER THE AREA AND EXPECT MID
LEVEL WARM AIR ADVECTION WILL ALLOW SOME LIGHT SNOW TO FALL BUT
WEAKER SURFACE FLOW WILL LIMIT ANY UPSLOPE FACTOR. AS THE ARCTIC
AIR RETREATS TO THE EAST THIS WILL ALLOW FOR A SLIGHT MODERATION
IN TEMPERATURES AND LEESIDE TROUGHING IS EXPECTED TO FORM LATE IN
THE AFTERNOON OR EARLY EVENING. WITH STRONG SURFACE PRESSURES
REMAINING STAGNANT OVER SOUTHEAST IDAHO GAP FLOW WINDS SHOULD BE
ON THE INCREASE THURSDAY NIGHT BUT GRADIENTS ONLY PROGGED TO REACH
10 TO 20 MB AT THIS TIME SO MAY NOT NEED A WIND ADVISORY FOR GAP
FLOW AREAS QUITE YET.
BORSUM
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MODELS REMAIN CONSISTENT WITH BUILDING RIDGE INTO THE AREA FOR
LATE WEEK INTO EARLY NEXT WEEK. THIS WILL BRING MUCH ABOVE
TEMPERATURES ALONG WITH DRY CONDITIONS. INCREASED HIGH
TEMPERATURES A FEW DEGREES TO STAY ABOVE GUIDANCE WHICH TENDS TO
UNDER DO TEMPERATURES HEADING INTO A STRONG RIDGE. A WEAK
DISTURBANCE WILL DROP THROUGH THE AREA LATE FRIDAY NIGHT INTO
SATURDAY MORNING...BUT THE FAST MOVEMENT OF THE SYSTEM AND LACK
OF SIGNIFICANT MOISTURE POINTS TO ONLY A SLIGHT CHANCE OF SNOW
SHOWERS OVER EASTERN ZONES DURING THIS TIME FRAME. MODELS HAVE
ALSO BEEN CONSISTENT WITH ADVERTISING A RETURN TO WINTER
CONDITIONS TUESDAY INTO WEDNESDAY AS A CHUNK OF ARCTIC AIR SLIDES
SOUTHWARD. CERTAINLY TIME FOR IDEAS TO CHANGE OUT THAT FAR BUT
HAVE TRENDED TEMPERATURES DOWN BY DAY 8. CHAMBERS
&&
.AVIATION...
WINDY CONDITIONS WILL PERSIST THROUGH THE EARLY EVENING BEFORE
DIMINISHING LATE TONIGHT. A FEW LIGHT SHOWERS WILL CONTINUE TO
STREAM ACROSS EASTERN ZONES FROM TIME TO TIME...BUT VFR
CONDITIONS SHOULD PREVAIL. LATE TONIGHT A COLD FRONT WILL PRESS
INTO THE EASTERN PORTION OF THE FORECAST AREA...AND INTO CENTRAL
AREAS AROUND DAWN. WINDS WILL INCREASE IN THE SHERIDAN AREA A FEW
HOURS AHEAD OF THE FRONT WITH PERIODIC GUSTS OF 35 TO 50 MPH
POSSIBLE. BEHIND THE FRONT NORTHEAST WINDS WILL BRING PERIODS OF
SNOW AND IFR CEILINGS AND VISIBILITIES. IT APPEARS HEAVIER SNOW
WILL STAY EAST OF A RED LODGE TO HARLOWTON LINE WITH THIS SYSTEM.
EXPECT OCCASIONAL MOUNTAIN OBSCURATION FOR THE WESTERN MOUNTAINS
BY MORNING...WITH TOTAL OBSCURATION FOR THE BIG HORN MOUNTAINS BY
LATE TONIGHT.
FOR EARLY WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON...A
CORRIDOR OF MODERATE TO HEAVY SNOW IS EXPECTED TO DEVELOP FROM
ROUNDUP TO BILLINGS TO SHERIDAN. WITHIN 50NM EITHER SIDE OF THIS
LINE EXPECT VISIBILITIES BELOW 1/2SM AT TIMES IN MODERATE TO
OCCASIONALLY HEAVY SNOW AND CEILINGS UNDER 500 FEET. THESE
CONDITIONS MAY PERSIST INTO WEDNESDAY NIGHT AS THE COLD FRONT
BECOMES STATIONARY AND THEN SHIFTS EASTWARD AS A WARM FRONT.
CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 026/027 017/037 027/048 035/050 032/052 036/050 038/044
78/S 70/B 00/N 00/U 00/U 00/U 00/U
LVM 029/035 025/045 034/051 038/051 030/052 035/050 034/044
13/S 20/B 00/N 00/U 00/U 00/U 00/U
HDN 021/026 008/034 023/046 029/049 029/052 029/051 028/046
88/S 70/B 00/U 00/U 00/U 00/U 00/U
MLS 007/008 903/021 012/042 027/043 022/048 027/046 026/041
75/S 41/B 00/U 22/S 00/U 00/U 00/U
4BQ 012/015 901/029 019/052 030/051 026/051 028/051 029/046
77/S 63/S 00/U 22/S 00/U 00/U 00/U
BHK 902/000 908/019 010/046 022/044 020/046 023/045 020/040
62/S 11/B 10/U 22/S 00/U 00/U 00/U
SHR 023/027 014/037 024/053 026/050 025/052 026/049 030/047
89/S 72/O 00/U 00/U 00/U 00/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 6 AM WEDNESDAY TO 6 AM
MST THURSDAY FOR ZONES 29-35-38-57.
WINTER WEATHER ADVISORY IN EFFECT FROM 3 AM WEDNESDAY TO 3 AM
MST THURSDAY FOR ZONES 30-31-36-58.
WY...WINTER WEATHER ADVISORY IN EFFECT FROM 6 AM WEDNESDAY TO 6 AM
MST THURSDAY FOR ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
000
FXUS65 KGGW 132205
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
305 PM MST TUE JAN 13 2009
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
SURFACE LOW MOVING INTO WESTERN NORTH DAKOTA WITH FRONT TRAILING
BACK INTO SOUTHWEST SASKATCHEWAN. VERY STRONG WINDS HAVE DEVELOPED
SOUTHWEST OF THIS FRONT...MIXING VERY WARM AIR TO THE SURFACE.
WINDS HAVE CREATED OCCASIONAL WHITEOUT CONDITIONS ACROSS THE
NORTHEAST ZONES...WHERE THERE HAS NOT BEEN AS MUCH ICE AND SNOW IS
LOOSER. THUS HAVE ISSUED A WINTER WEATHER ADVISORY FOR BLOWING
SNOW FOR THE EVENING OVER THE FAR NORTHEAST.
FRONT WILL SAG SOUTHWARD OVERNIGHT...USHERING ARCTIC AIR BACK INTO
NORTHEAST MONTANA. WINDS WILL DIMINISH OVERNIGHT AS LOW LEVEL JET
MOVES SOUTHEAST...BUT COLD AIR ADVECTION SUBSIDENCE WILL MAKE THIS
SLOW. AS TEMPERATURES DROP TO NEAR OR BELOW ZERO...BREEZING
CONDITIONS WILL LEAD TO WIND CHILLS BELOW MINUS 20. HAVE ISSUED
WIND CHILL WARNING FOR LATE TONIGHT THROUGH WEDNESDAY MORNING FOR
THE LOW WIND CHILLS.
FRONT EXPECTED TO HANGUP ACROSS CENTRAL MONTANA ON WEDNESDAY AS
HIGH PRESSURE DROPS INTO THE DAKOTAS. EXPECT SOME PRECIPITATION IN
THE CHANNELED VORTICITY ALONG THIS BOUNDARY...BUT WILL BE
GENERALLY LIGHT. OVERALL EXPECT 2 TO 4 INCHES OF SNOW FROM EARLY
WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT. HEAVIEST AMOUNTS
WILL BE IN THE LITTLE ROCKIES.
FRONT LIFTS BACK TO THE NORTHEAST ON THURSDAY WITH HIGH PRESSURE
MOVING OFF THE SOUTHEAST. UPPER RIDGE OVER THE WEST COAST BEGINS
PUSHING WARM AIR ACROSS THE DIVIDE AND OVER THE ARCTIC AIRMASS IN
EASTERN MONTANA. EBERT
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
SOLID OPERATIONAL MODEL AND ENSEMBLE AGREEMENT CONTINUES THROUGH
EARLY NEXT WEEK. A LARGE UPPER LEVEL RIDGE IS EXPECTED TO MOVE
OVER THE WESTERN UNITED STATES THIS WEEKEND BRINGING WELL ABOVE
NORMAL TEMPERATURES. UPPER HEIGHTS BEGIN TO FALL EARLY NEXT WEEK
IN RESPONSE TO A DIGGING TROUGH MOVING FROM THE GULF OF ALASKA
INTO WESTERN CANADA. NONETHELESS...1000-500MB THICKNESS VALUES
REMAIN IN EXCESS OF 550DAM...SO TEMPERATURES WILL CONTINUE TO BE
WELL ABOVE AVERAGE. 12Z GFS AND ECMWF BOTH INDICATE THAT THE
AFOREMENTIONED TROUGH WILL CONTINUE TO DIG SOUTHEAST AND PUSH A
COLD FRONT THROUGH THE AREA BY THE MIDDLE OF NEXT WEEK...BUT
TIMING AND STRENGTH ISSUES EXIST.
THE MAIN CHANGE TO THE EXTENDED FORECAST WAS TO TREND TEMPERATURES
UPWARD FRIDAY...SUNDAY...AND MONDAY. ESPECIALLY OVER THE
SOUTHWESTERN PORTION OF THE CWA WHERE SNOW COVER IS LITTLE TO NON-
EXISTENT. THE REASONING FRIDAY IS THE PASSAGE OF A SHORTWAVE
TROUGH...WHICH SHOULD ENHANCE MIXING....AND THEN THE UPPER RIDGE
EXERTS ITSELF SUNDAY AND MONDAY. OTHERWISE...ONLY A FEW MINOR
ADJUSTMENTS FOR COORDINATION PURPOSES. AJZ
PREVIOUS LONG TERM DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT FOR THE MOST PART THRU THE
EXTENDED PERIOD. IT APPEARS THAT THE END OF THIS WEEK THRU EARLY
NEXT WEEK WILL BE ONE OF THE NICEST STRETCHES WE HAVE HAD FOR SOME
TIME AS WE WILL BE UNDER THE EFFECTS A BIG UPPER RIDGE. THE
BEGINNING OF THE PERIOD ON THURSDAY NIGHT HAS THE WESTERN UPPER
RIDGE AXIS FAR ENUF EAST TO PUSH THE ARCTIC AIR INTO THE DAKOTAS
AND GIVE US 850 MB TEMPERATURES ABOVE ZERO CELSIUS. THE WARM AIR
ADVECTION THEN CONTINUES THRU THE WEEKEND AND EARLY NEXT WEEK AS
THE RIDGE AXIS MOVES EAST. ONLY REAL WRINKLE AMONGST THE MODELS IS
THE HANDLING OF A FAST-MOVING UPPER DISTURBANCE IN THE NORTHWEST
FLOW FRIDAY NIGHT INTO SATURDAY. OPERATIONAL GFS IS THE ODD MODEL
OUT WITH THIS FEATURE WITH RESPECT TO IT BEING MOIST ENUF HERE TO
GENERATE SOME LIGHT PRECIPITATION AS IT MOVES DIRECTLY OVERHEAD.
REMAINING OPERATIONAL MODELS TAKE THIS FEATURE FARTHER EAST INTO
THE DAKOTAS AND LEAVE THE LOWER LEVELS OF THE ATMOSPHERE HERE ON
THE DRY SIDE. SO FOR NOW WILL KEEP THINGS DRY AND SIMPLY ADD IN
SOME CLOUDS TO ACCOUNT FOR THE PASSAGE OF THIS WAVE. OTHERWISE NOT
EXPECTING MUCH IN THE WAY OF CLOUDS THRU MOST OF THE EXTENDED
PERIOD. TEMPERATURES WILL DEFINITELY BE WARMER THAN WE HAVE HAD
FOR SOME TIME. BIG QUESTION IS THE AMOUNT OF MIXING TO GET THE
WARM AIR DOWN TO THE SURFACE...AS OTHERWISE THE SNOW COVER WILL
AID IN KEEPING TEMPERATURES ON THE COOL SIDE DESPITE THE MILD AIR
ALOFT. FOR NOW WILL KEEP THE WARMING TEMPERED...ESPECIALLY AT
NIGHT AND FOR THE NORTHEAST HALF OR SO OF THE CWA. BUT IT WILL
STILL BE RELATIVELY MILD NONETHELESS. AS THE WEEK UNFOLDS
EXPECTING THAT A BETTER DETERMINATION OF EXPECTED WIND AND MIXING
CAN BE MADE.
&&
.AVIATION...
A COLD FRONT WILL PUSH THROUGH THE AREA TONIGHT WITH A NORTHWEST
WIND OF 15 TO 25KT...WITH GUSTS TO 35KT...STEADILY VEERING TO THE
EAST AND DECREASING TO LESS THAN 10KT BY WEDNESDAY MORNING. THE
COLD AIRMASS BEHIND THE FRONT WILL BE SHALLOW WITH RELATIVELY
WARMER AIR ALOFT CREATING WIDESPREAD MVFR STRATUS THIS EVENING
THROUGH WEDNESDAY. AJZ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR DANIELS-
SHERIDAN-WESTERN ROOSEVELT-NORTHERN VALLEY-EASTERN ROOSEVELT.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 10 AM MST
WEDNESDAY FOR CENTRAL AND SOUTHERN VALLEY-DANIELS-SHERIDAN-
WESTERN ROOSEVELT-MCCONE-RICHLAND-DAWSON-WIBAUX-NORTHERN
PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT.
&&
$$
WEATHER.GOV/GLASGOW
000
FXUS65 KTFX 132137
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
237 PM MST TUE JAN 13 2009
.DISCUSSION...
TONIGHT THROUGH THURSDAY...SURFACE LOW PRESSURE SYSTEM CONTINUES
TO ACCELERATE AWAY FROM MONTANA THIS AFTERNOON. AN INVERTED LOW
PRESSURE TROUGH EXTENDS NORTHWEST FROM THIS SYSTEM THROUGH NORTH
CENTRAL MONTANA AND SOUTHERN ALBERTA. MODELS CONTINUE TO BE IN
GOOD AGREEMENT BRINGING THE TROUGH SOUTH WITH WINDS SHIFTING TO
THE NORTH AS A CANADIAN COLD FRONT PUSHES INTO MONTANA. THIS
SOLUTION REMAINS ON TRACK AS SURFACE OBSERVATIONS SHOW THAT THE
COLD FRONT HAS ALREADY PUSHED INTO THE LETHBRIDGE AREA. THIS
FRONT WILL CONTINUE PUSHING INTO MY FORECAST AREA OVERNIGHT WITH
SCATTERED PRECIPITATION DEVELOPING ACROSS MY NORTHEAST ZONES
DURING THE EVENING THEN BECOMING MORE WIDESPREAD ALONG A
CONVERGENCE BOUNDARY THAT SHOULD SET UP ALONG A LINE FROM NEAR
HAVRE TO LEWISTOWN. IT APPEARS THAT SNOW WILL BECOME LIKELY ACROSS
ALL EASTERN PORTIONS OF NORTH CENTRAL MONTANA BY MORNING WITH SNOW
GRADUALLY TAPERING OFF FROM NORTHWEST TO SOUTHEAST DURING THE
AFTERNOON. AM EXPECTING 12 TO 18 HOUR SNOW TOTALS OF 2 TO 5 INCHES
IN THIS AREA SO WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY
FOR SNOW. AT THIS TIME IT DOES NOT APPEAR THAT THE GREAT FALLS
AREA WILL RECEIVE MORE THAN A CHANCE OF SNOW WITH PERHAPS AN INCH
OR SO OF ACCUMULATION. HOWEVER...THERE IS A DANGER THAT THE MODELS
HAVE THE BOUNDARY LOCATED TOO FAR TO THE EAST. IF SO...THERE IS A
POSSIBILITY THAT OVERNIGHT SHIFTS MAY DRASTICALLY INCREASE POPS
AND SNOW AMOUNTS FOR CENTRAL AND WESTERN PORTIONS OF NORTH CENTRAL
MONTANA. RESIDUAL SNOW SHOWERS WILL LINGER ACROSS THE EASTERN
PLAINS WEDNESDAY EVENING BUT SHOULD DIMINISH OVERNIGHT AS THE
CANADIAN AIRMASS SLIDES EAST. BY THURSDAY THE UPPER LEVEL RIDGE
OVER THE WEST COAST SHOULD BEGIN TO EDGE INTO THE NORTHERN ROCKY
MOUNTAIN REGION ALLOWING TEMPERATURES TO INCREASE ONCE AGAIN AS
DOWNSLOPE WINDS REASSERT THEMSELVES AND CLEARING SKIES MOVE INTO
CENTRAL MONTANA. MPJ
THURSDAY NIGHT THROUGH SUNDAY NIGHT. MODELS MAINTAINED GOOD
AGREEMENT ON DEVELOPMENT OF A BROAD AND WELL-AMPLIFIED PACIFIC UPPER
RIDGE THAT WILL DOMINATE THE WEATHER ACROSS THE WESTERN US AND SW
CANADA FOR THE LATTER HALF OF THIS WEEK. THIS WILL LEAD TO SEVERAL
DAYS OF DRY CONDITIONS WITH MAX TEMPERATURES OF 10 TO POSSIBLY AS
HIGH AS 20 DEG ABOVE NORMAL ACROSS ALL ZONES BY SUNDAY. MODELS
STILL DEPICT A COUPLE OF SHORTWAVE TROFS COMING OVER THE TOP OF THE
RIDGE DURING THIS PERIOD BUT THEY ARE NOW SHOWN FURTHER EAST AND
CONSIDERABLY DRIER THAT YESTERDAYS MODEL RUNS...SO HAVE REDUCED SKY
COVER GRIDS DOWN TO MOSTLY CLEAR SKIES THRU SUNDAY. THIS WILL ALLOW
NIGHTTIME TEMPS TO DROP BACK BELOW FREEZING EACH NIGHT SO REFREEZING
OF MELTED SNOW/ICE WILL BE A CONCERN DURING THE MORNING HOURS.
WARANAUSKAS
MONDAY AND TUESDAY...LATEST MODELS DEPICT A HIGH PRESSURE RIDGE
OVER THE WESTERN STATES MONDAY. BY TUESDAY AFTERNOON THE RIDGE IS
EXPECTED TO MOVE SOUTH AS AN APPROACHING LOW PRESSURE TROUGH MOVES
INTO THE PACIFIC NORTHWEST. TEMPERATURES WILL BE ABOVE SEASONAL
AVERAGES FOR MUCH OF THE REGION. SAUCIER
&&
.AVIATION...
UPDATED 1800Z.
MOIST NW FLOW ALOFT CONTINUES OVER THE REGION THROUGH THE NEXT 24
HRS. AT THE SURFACE...A TROUGH OF LOW PRESSURE EXTENDING FROM
SOUTHERN ALBERTA INTO EASTERN MT WILL MOVE OFF TO THE SOUTHEAST
TONIGHT...ALLOWING A SURFACE FRONTAL BOUNDARY TO SLIDE SOUTH INTO
NORTHCENTRAL MT TONIGHT. EXPECT THE BOUNDARY TO MOVE AS FAR SOUTH AS
A LINE FROM KCTB TO KBIL BY WED MORNING BEFORE STALLING AND SHIFTING
OFF TO THE EAST BY WEDNESDAY AFTERNOON. EXPECT AN AREA OF LIGHT
SNOW TO DEVELOP ALONG AND TO THE NE OF THE FRONTAL BOUNDARY
TONIGHT...WHERE LOWER LEVEL MOISTURE/CLOUDS WILL INCREASE WITH
NORTH TO NORTHEAST SURFACE WINDS. VFR CONDITIONS WILL GENERALLY
PREVAIL THROUGH EARLY THIS EVENING UNDER BROKEN MID CLOUD-COVER.
EXPECT MVFR TO LOCAL IFR CONDITIONS ACROSS NORTH CENTRAL MT
TERMINALS LATER TONIGHT AS SNOW DEVELOPS WITH GREATEST IMPACT AT THE
KLWT AND KHVR TERMINALS THROUGH WED MORNING. HOENISCH
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 23 30 23 45 / 20 40 10 0
CTB 20 30 23 45 / 20 20 10 0
HLN 27 36 23 44 / 10 10 10 0
BZN 24 38 20 44 / 10 20 10 0
WEY 15 30 11 31 / 20 20 20 10
DLN 20 34 18 42 / 0 10 10 0
HVR 3 10 5 33 / 60 60 30 10
LWT 18 25 18 42 / 60 70 40 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MST
WEDNESDAY FOR MTZ011-013-047-050-051.
&&
$$
SHORT TERM...MPJ
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...HOENISCH
WEATHER.GOV/GREATFALLS
000
FXUS65 KMSO 132128
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
228 PM MST TUE JAN 13 2009
...WIDESPREAD LOW CLOUDS AND FOG STILL ON TAP FOR LATE THIS WEEK
THROUGH THE HOLIDAY WEEKEND...
.DISCUSSION...SURFACE AND UPPER LEVEL RIDGE STILL EXPECTED TO BUILD OVER
THE INTER-MOUNTAIN WEST BY FRIDAY DRYING OUT THE MID AND UPPER
LEVELS. WITH AMPLE LOW LEVEL MOISTURE LINGERING ACROSS NORTH
CENTRAL IDAHO VALLEYS AND CENTRAL AND NORTHWEST MONTANA
VALLEYS. THE STAGE IS BEING SET FOR WIDESPREAD...LOCALLY DENSE FOG
TO DEVELOP AND LINGER THROUGH THE HOLIDAY WEEKEND. MAIN IMPACT
FROM THIS WEATHER WILL BE AIR STAGNATION AND AIR
TRAVEL...THEREFORE A HAZARDOUS WEATHER OUTLOOK HIGHLIGHTING WILL
BE ISSUED.
TONIGHT THROUGH THURSDAY...A PROGRESSIVE NORTHWEST TO NORTHERLY
FLOW WILL KEEP MID AND HIGH LEVEL CLOUDS OVER THE INTER-MOUNTAIN
REGION. GIVEN THE PRESSURE GRADIENT WILL BE DECREASING OVER NORTH
CENTRAL IDAHO AND WESTERN MONTANA RENDERING THE WINDS CALM IN
ALMOST ALL VALLEY LOCATIONS...THE FATE OF THE TEMPERATURES WILL
LIE SOLELY IN THE CLOUD COVER. CURRENT SATELLITE INDICATES THERE
WILL BE SOME PARTIAL CLEARING THIS EVENING ACROSS THE REGION BEFORE
THE NEXT BATCH OF CLOUDS MOVES IN. THIS PARTIAL CLEARING COULD BE
ENOUGH TO ALLOW TEMPERATURES TO FALL RATHER QUICKLY THEN HOLDING
STEADY THE REMAINDER OF THE NIGHT. CURRENT TREND FOR THE NEXT 48
HOURS IS GRADUAL COOLING EACH DAY AS INVERSIONS BEGIN TO DEVELOP
FROM LACK OF MIXING.
FRIDAY THROUGH MONDAY...A STRONG RIDGE OF HIGH PRESSURE SHOULD
SLOWLY SHIFT EASTWARD OVER THE REGION. AS THIS OCCURS...THE
ATMOSPHERE WILL BECOME INCREASINGLY STABLE WITH MILD CONDITIONS IN
THE MOUNTAINS AND COLD AIR POOLING IN THE VALLEYS. THE MAIN IMPACT
WILL BE TWO FOLD. FIRST...INCREASING AREAS OF FOG SHOULD OCCUR IN
THE VALLEYS. SECOND...WITH A VERY STABLE ATMOSPHERE...POLLUTANTS
WILL BUILD UP IN THE LOWER ATMOSPHERE.
&&
.AVIATION...NORTHWESTERLY FLOW ALOFT WILL CONTINUE TO BRING MID-
AND UPPER-LEVEL CLOUDS THROUGH NORTH CENTRAL IDAHO AND WESTERN
MONTANA. ISOLATED MOUNTAIN SNOW SHOWERS ARE POSSIBLE THROUGH
WEDNESDAY MAINLY IN THE NORTH. A WESTERLY PRESSURE GRADIENT
CONTINUES ITS PLACE OVER WESTERN MONTANA CREATING GUSTY WINDS
MAINLY IN THE HIGHER TERRAIN AND AT KBTM. THE GRADIENT WILL RELAX
BY 00Z THIS EVENING. OTHER THAN THE SHOWERS AND WINDS CONDITIONS
LOOKS FAVORABLE FOR FLIGHT ACTIVITIES THROUGH WEDNESDAY.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&
$$
SHORT TERM...MEAD
LONG TERM....BAUCK
AVIATION...KITSMILLER
000
FXUS65 KTFX 131742
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1040 AM MST TUE JAN 13 2009
UPDATED AVIATION DISCUSSION
.UPDATE...SURFACE LOW PRESSURE SYSTEM OVER SOUTHERN ALBERTA IS
ALREADY MOVING EAST ALLOWING DOWNSLOPE PRESSURE GRADIENTS ALONG
THE ROCKY MOUNTAIN FRONT TO WEAKEN. WILL GO AHEAD AND CANCEL THE
HIGH WIND WARNING WITH THIS UPDATE PACKAGE. BAND OF CLOUD COVER
ASSOCIATED WITH SHORTWAVE ENERGY HAS ALREADY MOVED THROUGH MUCH OF
MY CWA AS WELL...SO WILL ALSO UPDATE TO LOWER CLOUD COVER ACROSS
MUCH OF NORTH CENTRAL MONTANA DOWN TO PARTLY CLOUDY FOR THE
REMAINDER OF TODAY. FINALLY...TEMPERATURES ARE ALREADY IN THE
UPPER 30S TO 40S ACROSS MUCH OF THE REGION. HAVE BUMPED FORECAST
MAX TEMPERATURES FOR TODAY UPWARD ACROSS THE ENTIRE CWA. FOR
TONIGHT AND WEDNESDAY...IT STILL LOOKS AS IF A BACKDOOR COLD FRONT
WILL MOVE INTO EASTERN PORTIONS OF NORTH CENTRAL MONTANA. FOR THE
AFTERNOON PACKAGE I ANTICIPATE THAT I WILL BE BUMPING POPS UP
FROM KHVR DOWN TO KLWT...AND WILL LOOK INTO WHETHER OR NOT A
WINTER WEATHER ADVISORY WILL NEED TO BE ISSUED. MODELS ARE NOW
KEEPING PRECIPITATION GENERALLY EAST OF GREAT FALLS...SO DO NOT
ANTICIPATE THAT THE CITY WILL RECEIVE MORE THAN A CHANCE OF LIGHT
SNOW. MPJ
&&
.AVIATION...
UPDATED 1800Z.
MOIST NW FLOW ALOFT CONTINUES OVER THE REGION THROUGH THE NEXT 24
HRS. AT THE SURFACE...A TROUGH OF LOW PRESSURE EXTENDING FROM
SOUTHERN ALBERTA INTO EASTERN MT WILL MOVE OFF TO THE SOUTHEAST
TONIGHT...ALLOWING A SURFACE FRONTAL BOUNDARY TO SLIDE SOUTH INTO
NORTHCENTRAL MT TONIGHT. EXPECT THE BOUNDARY TO MOVE AS FAR SOUTH AS
A LINE FROM KCTB TO KBIL BY WED MORNING BEFORE STALLING AND SHIFTING
OFF TO THE EAST BY WEDNESDAY AFTERNOON. EXPECT AN AREA OF LIGHT
SNOW TO DEVELOP ALONG AND TO THE NE OF THE FRONTAL BOUNDARY
TONIGHT...WHERE LOWER LEVEL MOISTURE/CLOUDS WILL INCREASE WITH
NORTH TO NORTHEAST SURFACE WINDS. VFR CONDITIONS WILL GENERALLY
PREVAIL THROUGH EARLY THIS EVENING UNDER BROKEN MID CLOUD-COVER.
EXPECT MVFR TO LOCAL IFR CONDITIONS ACROSS NORTH CENTRAL MT
TERMINALS LATER TONIGHT AS SNOW DEVELOPS WITH GREATEST IMPACT AT THE
KLWT AND KHVR TERMINALS THROUGH WED MORNING. HOENISCH
&&
.PREV DISCUSSION...
/ISSUED 430 AM MST TUE JAN 13 2009/
TUESDAY THROUGH THURSDAY...WINDY CONDITIONS WILL DOMINATE EARLY
TUESDAY WITH VELOCITIES DECREASING AFTERNOON IN MOST AREAS. WILL
KEEP THE HIGH WIND WARNING IN EFFECT FOR THE NEXT COUPLE HOURS AT
LEAST...SINCE THE WINDS ARE STILL NEAR CRITERIA AND NOT EXPECTING
A SHARP DECREASE IN SPEEDS QUITE YET. THERE IS A POSSIBILITY TO
SEE SOME ISOLATED SHOWERS TODAY AS ABUNDANT MOISTURE ADVECTION
ALOFT REMAINS ALONG WITH A WEAK UPPER LEVEL DISTURBANCE. ON
WEDNESDAY A BACKDOOR COLD FRONT WILL MOVE IN FROM CANADA AND BRING
WITH IT COLDER TEMPERATURES AND SOME SNOWFALL ESPECIALLY IN THE
EASTERN PARTS OF THE CWA. NOT ISSUING ANY HIGHLIGHTS RIGHT NOW AS
ACCUMULATION AMOUNTS ARE NEAR CRITERIA LEVELS...NOT WATCH OR
WARNING. WILL MONITOR THE EVENT CLOSELY ON THE NEXT MODEL RUN AND
WILL ALLOW THE NEXT SHIFT TO EVALUATE ANY CHANGES. SUK
THURSDAY NIGHT THROUGH SUNDAY NIGHT. MODELS MAINTAINED GOOD
AGREEMENT ON DEVELOPMENT OF A BROAD AND WELL-AMPLIFIED PACIFIC UPPER
RIDGE THAT WILL DOMINATE THE WEATHER ACROSS THE WESTERN US AND SW
CANADA FOR THE LATTER HALF OF THIS WEEK. THIS WILL LEAD TO SEVERAL
DAYS OF DRY CONDITIONS WITH MAX TEMPERATURES OF 10 TO POSSIBLY AS
HIGH AS 20 DEG ABOVE NORMAL ACROSS ALL ZONES BY SUNDAY. MODELS
STILL DEPICT A COUPLE OF SHORTWAVE TROFS COMING OVER THE TOP OF THE
RIDGE DURING THIS PERIOD BUT THEY ARE NOW SHOWN FURTHER EAST AND
CONSIDERABLY DRIER THAT YESTERDAYS MODEL RUNS...SO HAVE REDUCED SKY
COVER GRIDS DOWN TO MOSTLY CLEAR SKIES THRU SUNDAY. THIS WILL ALLOW
NIGHTTIME TEMPS TO DROP BACK BELOW FREEZING EACH NIGHT SO REFREEZING
OF MELTED SNOW/ICE WILL BE A CONCERN DURING THE MORNING HOURS.
WARANAUSKAS
MONDAY AND TUESDAY...LATEST MODELS DEPICT A HIGH PRESSURE RIDGE
OVER THE WESTERN STATES MONDAY. BY TUESDAY AFTERNOON THE RIDGE IS
EXPECTED TO MOVE SOUTH AS AN APPROACHING LOW PRESSURE TROUGH MOVES
INTO THE PACIFIC NORTHWEST. TEMPERATURES WILL BE ABOVE SEASONAL
AVERAGES FOR MUCH OF THE REGION. SAUCIER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 49 23 29 22 / 10 20 50 30
CTB 47 20 29 21 / 10 20 20 20
HLN 52 26 35 23 / 10 10 20 10
BZN 41 26 37 21 / 0 10 30 10
WEY 33 14 30 11 / 10 20 20 20
DLN 44 20 33 18 / 10 10 10 10
HVR 44 8 14 5 / 20 30 30 30
LWT 47 19 24 17 / 10 30 60 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MPJ/SUK
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...HOENISCH
WEATHER.GOV/GREATFALLS
000
FXUS65 KGGW 131726
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
1026 AM MST TUE JAN 13 2009
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
UPDATE THIS MORNING MAINLY TO ADJUST TEMPERATURES AND
PRECIPITATION TYPES FOR TODAY. WARM AIR HAS INVADED THE SOUTHWEST
ZONES WHILE THE NORTHEAST REMAINS COLD. SURFACE LOW OVER SOUTHERN
SASKATCHEWAN EXPECTED TO SLIDE SOUTH ALONG FRONT OVER EASTERN
MONTANA TODAY. BEST CHANCE OF PRECIPITATION WILL BE JUST TO THE
EAST OF THE FRONT WHICH EXTENDS FROM SWIFT CURRENT TO SCOBEY TO
JUST WEST OF SIDNEY. WHILE WARMER AIR IS TO THE WEST OF THE
FRONT...SHALLOW INVERSION KEEPING COLDER AIR IN THE MILK/MISSOURI
VALLEYS. ADJUSTED TEMPERATURES TO REFLECT WHERE THE COLD AIR WILL
LINGER. SPREAD MIX OF PRECIPITATION FURTHER EAST TO REFLECT THE
WARMER AIR ALOFT...LEFT JUST SNOW IN FAR NORTHEAST TO THE LEFT OF
THE TRACK OF THE LOW.
AS LOW MOVES ACROSS NORTHEAST MONTANA THIS AFTERNOON...WINDS WILL
INCREASE BEHIND IT...AND CONTINUE INTO THE EVENING. WINDS EXPECTED
TO BE STRONG ENOUGH TO PRODUCE SOME BLOWING SNOW THIS EVENING
ALTHOUGH LITTLE LOOSE SNOW EXCEPT IN THE NORTHEAST. HAVE THUS
TRIMMED BACK THE MENTION OF BLOWING SNOW TO AREAS WHERE STRONGEST
WINDS ARE EXPECTED. EBERT
PREVIOUS SHORT TERM DISCUSSION...LARGE SCALE PATTERN REMAINS VERY
AMPLIFIED...WITH A LARGE HIGH PRESSURE ALOFT OVER THE PACIFIC
COAST STATES...CENTERED OVER CA COAST. NE MT IS IN A VERY STRONG
NW FLOW AROUND THIS HIGH...UP TO 150 KT AS SHOWN ON 00Z KGGW
SOUNDING. SATELLITE CHANNELS HAVE BEEN SHOWING QUITE A BIT OF
MOISTURE/CLOUDS MOVING OUR WAY IN THIS FLOW OVERNIGHT...BUT ONLY
WEAK SHORTWAVE ACTIVITY. WARM FRONT MOVING E ACROSS OUR W MOST
ZONES IS PROVIDING SOME LIFT FOR LIGHT SNOW IN OUR E...BUT
CONTINUING TO LOOK RATHER SPOTTY AND LIGHT AND LESS THAN
PREVIOUSLY EXPECTED. THE MAIN SHORTWAVE IN NW FLOW MOVES OFF INTO
ND AND WITH LESSENING OVERRUNNING...EXPECT ONLY SCATTERED LIGHT
ACCUMULATIONS TODAY. THE WARM FRONT HAS ALREADY CAUSED TEMPS TO
CLIMB WELL ABOVE FREEZING IN OUR SW. THIS WILL SPREAD E ACROSS THE
ENTIRE AREA TODAY AS THICKNESSES CLIMB TO THE 530S DM. MUCH OF THE
AREA WILL CLIMB TO THE 30S AND LOWER 40S FOR HIGHS.
THE LAST IN THE CURRENT STRING OF ARCTIC HIGHS IS QUICKLY
INTENSIFYING OVER NW CANADA THIS MORN. THIS WILL CONTINUE TO
INTENSIFY...TO A 1045-1050 MB CENTER...AS IT MOVES INTO W ND WED.
THIS SIMILAR TO THE PATTERN OF 2 DAYS AGO...WITH A SHARP ARCTIC
FRONTAL PASSAGE FOR NE NT TONIGHT...BUT COLDER AIR FOLLOWING THIS
FRONT. 850 MB WINDS ARE UP TO 50 KT...JUST A LITTLE LESS THAN THE
PREVIOUS FRONT THAT PRODUCED OVER 70 MPH WINDS...BUT NOT AS WELL
LINKED WITH THE STRONGER COLD ADVECTION. EVEN SO...MODELS SHOW UP
TO 40 KT WINDS AT 850 MB DURING THE MOST FAVORABLE LAPSE RATE
TIMES...WHICH ALSO SHOW SUPER ADIABATIC LAPSE RATES
AGAIN...INDICATIVE OF THE LOWER LEVEL TURBULENCE...AND SO WILL
HAVE WIDESPREAD BLOWING AND DRIFTING OF SNOW AGAIN. SIMILAR TO
LAST SYSTEM MODELS INDICATE ONLY LIGHT QPF...AND A PAIR OF RATHER
WEAK VORTICITY CENTERS JUST BRUSHING OUR NE. WILL LEAVE ANY
ADVISORY CONSIDERATIONS FOR THE DAY SHIFT...WHICH LOOK MOST
FAVORABLE AGAIN IN OUR N DUE TO THE POTENTIAL OF BLOWING SNOW AS
WELL AS WIND CHILL.
WARM FRONT MOVES BACK ACROSS THE AREA THU IN A PATTERN SIMILAR TO
YESTERDAY...BUT WITH LESS FAVORABLE LIFT/UPPER SUPPORT AND AIRMASS
DEPTH...SO KEEPING POPS VERY LOW.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
MODELS REMAIN IN GOOD AGREEMENT FOR THE MOST PART THRU THE
EXTENDED PERIOD. IT APPEARS THAT THE END OF THIS WEEK THRU EARLY
NEXT WEEK WILL BE ONE OF THE NICEST STRETCHES WE HAVE HAD FOR SOME
TIME AS WE WILL BE UNDER THE EFFECTS A BIG UPPER RIDGE. THE
BEGINNING OF THE PERIOD ON THURSDAY NIGHT HAS THE WESTERN UPPER
RIDGE AXIS FAR ENUF EAST TO PUSH THE ARCTIC AIR INTO THE DAKOTAS
AND GIVE US 850 MB TEMPERATURES ABOVE ZERO CELSIUS. THE WARM AIR
ADVECTION THEN CONTINUES THRU THE WEEKEND AND EARLY NEXT WEEK AS
THE RIDGE AXIS MOVES EAST. ONLY REAL WRINKLE AMONGST THE MODELS IS
THE HANDLING OF A FAST-MOVING UPPER DISTURBANCE IN THE NORTHWEST
FLOW FRIDAY NIGHT INTO SATURDAY. OPERATIONAL GFS IS THE ODD MODEL
OUT WITH THIS FEATURE WITH RESPECT TO IT BEING MOIST ENUF HERE TO
GENERATE SOME LIGHT PRECIPITATION AS IT MOVES DIRECTLY OVERHEAD.
REMAINING OPERATIONAL MODELS TAKE THIS FEATURE FARTHER EAST INTO
THE DAKOTAS AND LEAVE THE LOWER LEVELS OF THE ATMOSPHERE HERE ON
THE DRY SIDE. SO FOR NOW WILL KEEP THINGS DRY AND SIMPLY ADD IN
SOME CLOUDS TO ACCOUNT FOR THE PASSAGE OF THIS WAVE. OTHERWISE NOT
EXPECTING MUCH IN THE WAY OF CLOUDS THRU MOST OF THE EXTENDED
PERIOD. TEMPERATURES WILL DEFINITELY BE WARMER THAN WE HAVE HAD
FOR SOME TIME. BIG QUESTION IS THE AMOUNT OF MIXING TO GET THE
WARM AIR DOWN TO THE SURFACE...AS OTHERWISE THE SNOW COVER WILL
AID IN KEEPING TEMPERATURES ON THE COOL SIDE DESPITE THE MILD AIR
ALOFT. FOR NOW WILL KEEP THE WARMING TEMPERED...ESPECIALLY AT
NIGHT AND FOR THE NORTHEAST HALF OR SO OF THE CWA. BUT IT WILL
STILL BE RELATIVELY MILD NONETHELESS. AS THE WEEK UNFOLDS
EXPECTING THAT A BETTER DETERMINATION OF EXPECTED WIND AND MIXING
CAN BE MADE.
&&
.AVIATION...
ANOTHER SYSTEM SLATED TO MOVE ACROSS THE AREA TODAY. SO SOME LOWER
CEILINGS ARE EXPECTED AS WELL AS SOME LIGHT SNOW WHICH MAY REDUCE
VISIBILITY AT TIMES. IN GENERAL VFR CONDITIONS EARLY THIS MORNING
WILL BE GIVING WAY TO MVFR WITH SOME OCCASIONAL IFR. A COLD FRONT
WILL MOVE THRU LATE THIS AFTERNOON OR EARLY EVENING AND BRING A
WIND SHIFT TO NORTHWEST AND SPEEDS WILL INCREASE TO 15-25 KT.
TONIGHT ANY SNOW WILL BE ENDING AND CEILINGS ARE EXPECTED TO RISE
TO VFR. NORTHWEST WIND BECOMES NORTH AND GRADUALLY DECREASES TO
NEAR 10 KT BY WEDNESDAY MORNING. VFR CONDITIONS EXPECTED WEDNESDAY
WITH LIGHT WIND UNDER SURFACE HIGH PRESSURE.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
000
FXUS65 KTFX 131654
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
954 AM MST TUE JAN 13 2009
.UPDATE...SURFACE LOW PRESSURE SYSTEM OVER SOUTHERN ALBERTA IS
ALREADY MOVING EAST ALLOWING DOWNSLOPE PRESSURE GRADIENTS ALONG
THE ROCKY MOUNTAIN FRONT TO WEAKEN. WILL GO AHEAD AND CANCEL THE
HIGH WIND WARNING WITH THIS UPDATE PACKAGE. BAND OF CLOUD COVER
ASSOCIATED WITH SHORTWAVE ENERGY HAS ALREADY MOVED THROUGH MUCH OF
MY CWA AS WELL...SO WILL ALSO UPDATE TO LOWER CLOUD COVER ACROSS
MUCH OF NORTH CENTRAL MONTANA DOWN TO PARTLY CLOUDY FOR THE
REMAINDER OF TODAY. FINALLY...TEMPERATURES ARE ALREADY IN THE
UPPER 30S TO 40S ACROSS MUCH OF THE REGION. HAVE BUMPED FORECAST
MAX TEMPERATURES FOR TODAY UPWARD ACROSS THE ENTIRE CWA. FOR
TONIGHT AND WEDNESDAY...IT STILL LOOKS AS IF A BACKDOOR COLD FRONT
WILL MOVE INTO EASTERN PORTIONS OF NORTH CENTRAL MONTANA. FOR THE
AFTERNOON PACKAGE I ANTICIPATE THAT I WILL BE BUMPING POPS UP
FROM KHVR DOWN TO KLWT...AND WILL LOOK INTO WHETHER OR NOT A
WINTER WEATHER ADVISORY WILL NEED TO BE ISSUED. MODELS ARE NOW
KEEPING PRECIPITATION GENERALLY EAST OF GREAT FALLS...SO DO NOT
ANTICIPATE THAT THE CITY WILL RECEIVE MORE THAN A CHANCE OF LIGHT
SNOW. MPJ
&&
.AVIATION...
UPDATED 13/1130Z.
ANOTHER DAY OF MOIST NORTHWEST FLOW CONDITIONS WILL BRING WIDESPREAD
MID- AND UPPER LEVEL VFR CEILINGS FOR CENTRAL AND SOUTHWEST MT
TODAY. THE LEE-SIDE SURFACE TROF CURRENTLY OVER CENTRAL MT WILL BE
SLOW TO MOVE OFF TO THE EAST SO WINDS WILL CONTINUE TO GUST FROM 25
TO 40 KTS IN THE AREA FROM A KHLN-TO-KLWT LINE NORTH TO THE US/CAN
BORDER. THIS EVENING A BACKDOOR COLD FRONT WILL MOVE
EAST-SOUTHEASTWARD OUT OF SASKATCHEWAN AND EVENTUALLY STALL OUT
ALONG A LINE FROM KHVR TO KBIL. MOISTURE ACCOMPANYING THE FRONT
WILL PRODUCE LIGHT SNOW WITH MVFR AND SOME IFR CONDITIONS LIKELY
NEAR THE PRECIPITATION AREAS. WARANAUSKAS
&&
.PREV DISCUSSION...
/ISSUED 430 AM MST TUE JAN 13 2009/
TUESDAY THROUGH THURSDAY...WINDY CONDITIONS WILL DOMINATE EARLY
TUESDAY WITH VELOCITIES DECREASING AFTERNOON IN MOST AREAS. WILL
KEEP THE HIGH WIND WARNING IN EFFECT FOR THE NEXT COUPLE HOURS AT
LEAST...SINCE THE WINDS ARE STILL NEAR CRITERIA AND NOT EXPECTING
A SHARP DECREASE IN SPEEDS QUITE YET. THERE IS A POSSIBILITY TO
SEE SOME ISOLATED SHOWERS TODAY AS ABUNDANT MOISTURE ADVECTION
ALOFT REMAINS ALONG WITH A WEAK UPPER LEVEL DISTURBANCE. ON
WEDNESDAY A BACKDOOR COLD FRONT WILL MOVE IN FROM CANADA AND BRING
WITH IT COLDER TEMPERATURES AND SOME SNOWFALL ESPECIALLY IN THE
EASTERN PARTS OF THE CWA. NOT ISSUING ANY HIGHLIGHTS RIGHT NOW AS
ACCUMULATION AMOUNTS ARE NEAR CRITERIA LEVELS...NOT WATCH OR
WARNING. WILL MONITOR THE EVENT CLOSELY ON THE NEXT MODEL RUN AND
WILL ALLOW THE NEXT SHIFT TO EVALUATE ANY CHANGES. SUK
THURSDAY NIGHT THROUGH SUNDAY NIGHT. MODELS MAINTAINED GOOD
AGREEMENT ON DEVELOPMENT OF A BROAD AND WELL-AMPLIFIED PACIFIC UPPER
RIDGE THAT WILL DOMINATE THE WEATHER ACROSS THE WESTERN US AND SW
CANADA FOR THE LATTER HALF OF THIS WEEK. THIS WILL LEAD TO SEVERAL
DAYS OF DRY CONDITIONS WITH MAX TEMPERATURES OF 10 TO POSSIBLY AS
HIGH AS 20 DEG ABOVE NORMAL ACROSS ALL ZONES BY SUNDAY. MODELS
STILL DEPICT A COUPLE OF SHORTWAVE TROFS COMING OVER THE TOP OF THE
RIDGE DURING THIS PERIOD BUT THEY ARE NOW SHOWN FURTHER EAST AND
CONSIDERABLY DRIER THAT YESTERDAYS MODEL RUNS...SO HAVE REDUCED SKY
COVER GRIDS DOWN TO MOSTLY CLEAR SKIES THRU SUNDAY. THIS WILL ALLOW
NIGHTTIME TEMPS TO DROP BACK BELOW FREEZING EACH NIGHT SO REFREEZING
OF MELTED SNOW/ICE WILL BE A CONCERN DURING THE MORNING HOURS.
WARANAUSKAS
MONDAY AND TUESDAY...LATEST MODELS DEPICT A HIGH PRESSURE RIDGE
OVER THE WESTERN STATES MONDAY. BY TUESDAY AFTERNOON THE RIDGE IS
EXPECTED TO MOVE SOUTH AS AN APPROACHING LOW PRESSURE TROUGH MOVES
INTO THE PACIFIC NORTHWEST. TEMPERATURES WILL BE ABOVE SEASONAL
AVERAGES FOR MUCH OF THE REGION. SAUCIER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 49 23 29 22 / 10 20 50 30
CTB 47 20 29 21 / 10 20 20 20
HLN 52 26 35 23 / 10 10 20 10
BZN 41 26 37 21 / 0 10 30 10
WEY 33 14 30 11 / 10 20 20 20
DLN 44 20 33 18 / 10 10 10 10
HVR 44 8 14 5 / 20 30 30 30
LWT 47 19 24 17 / 10 30 60 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MPJ/SUK
LONG TERM...WARANAUSKAS/SAUCIER
AVIATION...WARANAUSKAS
WEATHER.GOV/GREATFALLS
000
FXUS65 KBYZ 131644
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
944 AM MST TUE JAN 13 2009
.SHORT TERM...VALID FOR TDY AND WED...
WINDS ARE CONTINUING OVER THE UPPER YELLOWSTONE VALLEY EXTENDING
EASTWARD TO BIG TIMBER AND REEDPOINT BUT PRESSURE GRADIENTS ARE AT
THEIR PEAK AND EXPECTED TO BEGIN TAPERING DOWNWARD. SURFACE LOW
OVER EASTERN MONTANA IS SLIDING SOUTHEASTWARD TODAY AND THIS
PATTERN WILL ALLOW GOOD MIXING TO CONTINUE TODAY AS TEMPERATURES
HAVE RISEN TO ABOVE FREEZING...EVEN AT BAKER. WILL ALLOW THE WIND
ADVISORY TO RUN UNTIL 2 PM WHEN GRADIENTS SLACKEN ENOUGH TO ALLOW
WINDS TO SLOW DOWN. RADAR LOOKS PRETTY LIGHT WITH SNOWFALL AND
NONE IS BEING REPORTED UPSTREAM AND THIS MAKES SENSE GIVEN DRIER
AIR HEADING TOWARDS THE REGION ON WATER VAPOR. STILL COULD SEE
SOME LIGHT SNOW OVER FALLON COUNTY WHERE THE SURFACE BOUNDARY IS
PROVIDING A BIT OF LIFT. SENT MINOR UPDATE. WILL BE SWITCHING
FOCUS TO THE SNOW THAT IS EXPECTED TO COME AS THE BACKDOOR COLD
FRONT HEADS INTO THE AREA. BORSUM
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MODELS CONTINUE TO BE IN GOOD AGREEMENT FOR THE EXTENDED WITH AN
OVERALL WARM UP EXPECTED BY THE END OF THE WEEK AND INTO EARLY
NEXT WEEK. ARCTIC BOUNDARY WILL STILL BE IN PLACE ALONG WITH A
WEAK WAVE IN A NORTHERLY FLOW ALOFT THURSDAY TO BRING A SLIGHT
CHANCE FOR LIGHT SNOW ACROSS THE EASTERN ZONES. AS A
RESULT...HAVE ADDED POPS FOR THURSDAY FROM ROSEBUD COUNTY
EASTWARD. HIGHS ACROSS THIS AREA WILL BE ON THE COLD SIDE OF THE
BOUNDARY WITH READINGS ONLY IN THE UPPER TEENS TO LOWER
20S...WITH TEMPERATURES ELSEWHERE ACROSS THE FORECAST AREA IN THE
30S AND 40S AS A DOWNSLOPE FLOW WILL BE IN PLACE. HIGH PRESSURE
STILL LOOKS TO BUILD IN FOR FRIDAY AND THROUGH THE WEEKEND.
MODELS SHOW HEIGHTS RISING EVEN THOUGH UPPER FLOW REMAINS OUT OF
THE NORTH. 700MB WARM AIR ADVECTION ACTUALLY COMES OUT OF CANADA
DURING THIS TIME. PRESSURE GRADIENTS FAIRLY TIGHT ACROSS THE WEST
RESULTING IN WINDY CONDITIONS FOR THE FAVORED GAP AREAS.
HOWEVER...AT THIS TIME...GRADIENT NOT FAVORABLE FOR ADVISORY
WINDS. THIS AREA LOOKS TO BE THE WARMEST ACROSS THE FORECAST AREA
AS WINDS WILL KEEP TEMPERATURES RELATIVELY MILD ESPECIALLY DURING
THE OVERNIGHT HOURS. A WEAK DISTURBANCE MOVES SOUTH OUT OF CANADA
FRIDAY NIGHT AND SATURDAY MORNING...MAINLY ACROSS THE EAST AND
HAVE THEREFORE ADDED A SLIGHT POP CHANCE FOR THOSE AREAS.
OTHERWISE...DRY AND MILD CONDITIONS CAN BE EXPECTED FOR THE
WEEKEND AND INTO THE EARLY PART OF NEXT WEEK. HOOLEY
&&
.AVIATION...
MAINLY MID AND HIGH LEVEL CLOUDS WILL STREAM DOWN FROM THE NORTH
TODAY. DRY CONDITIONS CAN BE EXPECTED ON THE PLAINS FROM KBIL
WESTWARD WITH VFR CONDITIONS PREVAILING. A CHANCE FOR SNOW
SHOWERS WILL BE POSSIBLE OVER THE MOUNTAINS WITH SOME MOUNTAIN
OBSCURATIONS LIKELY. EAST OF KBIL...ESPECIALLY FROM KMLS TO
KBHK...THERE WILL BE A CHANCE FOR SNOW SHOWERS RESULTING IN MVFR
TO IFR CONDITIONS AT TIMES. OTHERWISE...VFR CONDITIONS CAN BE
EXPECTED. IN ADDITION...STRONG AND GUSTY SURFACE WINDS WILL
CONTINUE ACROSS THE BEARTOOTH FOOTHILLS...INCLUDING KLVM.
SUSTAINED WINDS OF 30 TO 40KTS WITH GUSTS AROUND 55KTS WILL BE
POSSIBLE THROUGH THE EARLY AFTERNOON HOURS. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 047 026/027 015/036 028/047 034/052 027/050 030/052
0/N 38/S 60/B 00/U 00/U 00/U 00/U
LVM 047 029/035 023/044 035/049 036/055 027/050 030/050
0/N 13/S 20/B 00/N 00/U 00/U 00/U
HDN 047 021/026 006/033 024/047 028/050 024/051 027/049
1/N 68/S 61/B 00/U 00/U 00/U 00/U
MLS 042 007/008 905/020 013/043 021/042 018/045 022/047
2/W 75/S 40/B 00/U 22/S 00/U 00/U
4BQ 043 012/015 903/028 020/048 031/048 021/049 023/050
2/W 77/S 63/S 00/U 22/R 00/U 00/U
BHK 035 904/000 910/018 011/042 019/036 015/045 023/043
4/J 72/S 11/B 10/U 22/S 00/U 00/U
SHR 047 023/027 012/036 025/053 028/051 023/052 025/054
1/B 69/S 72/O 00/U 00/U 00/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 2 PM MST THIS AFTERNOON FOR
ZONE 65.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
000
FXUS65 KMSO 131520
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
820 AM MST TUE JAN 13 2009
.UPDATE...ADJUSTED TEMPERATURES UP FOR HIGHS TODAY IN MANY
LOCATIONS.
&&
.DISCUSSION...THE CLOUDS THAT REMAINED OVER WESTERN MONTANA ALL
NIGHT ACTUALLY ROSE TEMPERATURES OVERNIGHT TO READINGS AT OR
SURPASSING PREVIOUSLY FORECAST HIGHS. THESE CLOUDS ARE LIFTING TO
A HIGH DECK WITH SOME HOLES SO TEMPERATURES COULD ACTUALLY FALL A
FEW DEGREES THIS MORNING...BUT SHOULD REMAIN NEAR THE ADJUSTED
HIGH TEMPERATURES. AREAS ADJUSTED WERE FLATHEAD/MISSION/MISSOULA
AND BITTERROOT VALLEYS AND THE POTOMAC/SEELEY LAKE REGIONS OF
MONTANA AND NORTH CENTRAL IDAHO VALLEYS.
&&
.AVIATION...MAIN CONCERNS THROUGH THE WEEK WILL BE INCREASING
STRATUS AND FOG AS AN UPPER RIDGE PUSHES TOWARD THE REGION.
FOR TODAY...WIDESPREAD STRATUS AROUND 4500 AGL WILL PERSIST THROUGH MUCH
OF TODAY...WITH SOME PATCHY DRIZZLE OR LIGHT FREEZING DRIZZLE FROM
PASSING UPPER LEVEL WAVES. THE VALLEY FOG WILL SLOWLY INCREASE IN
COVERAGE TONIGHT AND WEDNESDAY NIGHT. HOWEVER...TEMPERATURE AND
MOISTURE SOUNDINGS INDICATE NORTHWEST MONTANA WILL KEEP A LOW
STRATUS DECK THROUGH AT LEAST MIDDAY THURSDAY. THIS WILL MAINTAIN
LOWER CEILINGS BUT PREVENT WIDESPREAD FOG FORMATION. FROM AROUND
MISSOULA SOUTHWARD...THOUGH...FOG IS EXPECTED TO BE THE MAIN
THREAT.
&&
.PREV DISCUSSION... /ISSUED 334 AM MST TUE JAN 13 2009/
DISCUSSION...
TODAY THROUGH WEDNESDAY NIGHT...THE UPPER RIDGE AXIS REMAINS OFF
THE WEST COAST WITH A NORTHWEST FLOW OVER THE NORTHERN ROCKIES.
THERE IS QUITE A BIT OF LOW AND MID LEVEL MOISTURE IN THIS FLOW.
STRATUS CLOUDS AROUND 4500 FEET OFF THE GROUND IS WIDESPREAD
ACROSS WEST CENTRAL AND NORTHWEST MONTANA...AS WELL AS NORTH
CENTRAL IDAHO. IN ADDITION MID LEVEL CLOUDS WILL CONTINUE TO MOVE
OVERHEAD IN THE NORTHWEST FLOW. ANY PRECIPITATION TODAY WILL BE
VERY LIGHT...AND VERTICAL TEMPERATURE PROFILES INDICATE IT WILL
LIKELY BE IN THE FORM OF DRIZZLE OR FREEZING DRIZZLE RATHER THAN
SNOW. THIS PATTERN WILL CONTINUE THROUGH WEDNESDAY WITH A MIX OF
DRIZZLE OR VERY LIGHT SNOW BEFORE DEEPER ATMOSPHERIC DRYING OCCURS
DURING THE LATTER HALF OF THE WEEK.
VERTICAL TEMPERATURE AND DEW POINT PROFILES ALSO INDICATE LOW
STRATUS MAY BE THE MAIN CONCERN IN THE VALLEYS OF NORTHWEST
MONTANA WITH ONLY PATCHY FREEZING FOG AT THE SURFACE THROUGH EARLY
THURSDAY. HOWEVER...FROM AROUND MISSOULA SOUTH...THESE PROFILES
INDICATE MORE OF FOG SCENARIO WITH LITTLE CLOUD COVER OFF THE
GROUND.
THURSDAY THROUGH MONDAY...A STRONG RIDGE OF HIGH PRESSURE WILL SHIFT
OVER NORTH CENTRAL IDAHO AND WESTERN MONTANA. UNDER THIS WEATHER
PATTERN...INVERSIONS WILL INTENSIFY WITH COLD AIR POOLING UP IN
THE VALLEYS AND RELATIVELY WARM AIR ON THE MID SLOPES AND MOUNTAIN
RIDGES. FOG AND LOW STRATUS WILL INCREASE IN THE VALLEYS WITH POOR
MIXING CONDITIONS.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&
$$
UPDATE/AVIATION...MEAD
PREVIOUS DISCUSSION....WHITMORE/KOLATA
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