[top]
000
FXUS63 KFGF 200150
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
850 PM CDT FRI SEP 19 2008
.DISCUSSION...MAIN CHALLENGE OVERNIGHT WILL BE TEMPS AND HOW FAR
THEY CAN DROP. THINK CURRENT MIN TEMP FORECAST IS PRETTY CLOSE.
SHOULD BE ENOUGH HIGH CLOUD COVER AND SFC WIND TO PREVENT TEMPS
FROM FALLING TOO FAR. AM A BIT WORRIED ABOUT N/NE PORTIONS OF THE
FA WHICH WILL BE IN CLOSER PROXIMITY TO SFC HIGH (LIGHTER WINDS) BY
MORNING. MODELS INDICATING MID-UPPER 30F DEW POINT VALUES HERE
AS WELL...WHILE BIAS CORRECTED GUIDANCE INDICATING UPPER 30F TEMPS
POSSIBLE. WILL LOWER TEMPS A BIT THIS AREA TO ACCOUNT FOR THIS
CONCERN. NO OTHER CHANGES NEEDED.
&&
.AVIATION...EXPECT VFR CONDITIONS TO PERSIST AT ALL TAF SITES THE
NEXT 24 HOURS. EXPECT WINDS NORTH-NORTHEAST. CLOUDS WILL BE
MINIMAL WITH ONLY SCATTERED DECKS AT OR ABOVE 15000 FEET.
&&
.PREV DISCUSSION... /ISSUED 255 PM CDT FRI SEP 19 2008/
SHORT TERM...
FCST CONCERNS ARE MAINLY TEMPS THIS WEEKEND THEN PCPN CHANCES
NEXT WEEK.
FIRST OFF...SHORT WAVE TROUGH NOTED BY 12Z GFS MODEL FROM FAR NW
WISCONSIN INTO ECNTRL SD WITH NARROW AXIS OF INSTABILITY AND SCT
TSTMS ALONG IT. THIS FEATURE WILL EVENTUALLY GET SWEEPED SOUTH AND
EAST AS MAIN COLD FRONT SWEEPS THROUGH TONIGHT.
THAT COLD FRONT WAS LOCATED FROM LOW PRESSURE OVER HUDSON BAY
SOUTHWEST TO JUST SOUTH OF BAUDETTE TO CROOKSTON TO MAYVILLE THEN
BACK TO NEAR MINOT. MORE OF A NORTH WIND BEHIND THE FRONT...BUT
SFC TEMPS STILL MILD WITH COOLER SFC AIR LOCATED WELL NORTH OF
FRONT NORTH OF A SASKATOON TO DAUPHIN TO RED LAKE ONTARIO LINE.
SFC HIGH NOTED IN NRN SASK WILL DROP QUICKLY SOUTHEAST INTO NW
ONTARIO SATURDAY WITH TIGHT 850 MB BAROCLINIC ZONE DEVELOPING FROM
NORTHEAST TO SOUTHWEST ACROSS THE FCST AREA. 850 MB TEMPS SATURDAY
PROGGED IN THE +2-4C RANGE NORTHEAST TO +14C RANGE SOUTHWEST AT
18Z SATURDAY WITH 925 MB TEMPS FROM +6C TO +16C. EXTRAPOLATION OF SFC
TEMPS UNDERNEATH SIMILAR TEMP RANGES IN SASK WOULD INDICATE TIGHT
HIGH TEMP GRADIENT WITH 55-58 AT FLAG ISLAND TO MID 60S AT DVL-
GFK-BJI TO 70 AT FARGO TO MID 70S FAR SOUTHWEST CORNER OF FCST
AREA (JMS-ABR). NAM AND MET MOS HAS BEEN THE COLDER TEMP-WISE
WHILE GFS/MAV MOS THE WARMER SOLN. USING A SOLN BETWEEN THE TWO
FOR TEMPS HAS WORKED OUT WELL RECENTLY AND CONTINUED TO DO SO FOR
TEMPS THIS WEEKEND. AS FOR CLOUD COVER...MODELS INDICATE A RIBBON
OF MID LEVEL MOISTURE TO SPREAD FROM NRN ALBERTA INTO SRN SASK
INTO NE ND/NRN MN TONIGHT INTO SATURDAY BEFORE BEING PUSHED EAST.
THIS LOOKS REASONABLE BASED ON UPSTREAM OBS SHOWING SCT-BKN MID
CLOUDS IN THE EDMONTON-SASKATOON AREAS.
HIGH WILL SLIDE EAST OF THE AREA SAT NIGHT WITH RETURN FLOW
SETTING UP QUICKLY OVER ERN ND PREVENT LARGE TEMP DROP WITH
COOLEST TEMPS AND LIGHTER WINDS OVER BDE-BJI AREAS...BUT EVEN
THERE ENOUGH OF A GRADIENT DEVELOPING TO KEEP TEMPS 40-45..SO
DESPITE CHILLY AIRMASS MOVING DOWN...IT MOVES OUT QUICK ENOUGH TO
PREVENT ANY FROST. SOUTHEAST WINDS AND WARM ADV ROAR INTO THE AREA
SUNDAY...UPPING TEMPS A GOOD 10 DEGREES OVER SATURDAY. NOSE OF
850-700 MB WARM ADVECTION COMBINED WITH 700 MOISTURE MAY PRODUCE A
FEW SHOWERS OR ISOLD THUNDER OVER NE MN SUNDAY...BUT LATEST MODEL
GUIDANCE SUGGEST THIS WILL BE EAST OF THE FCST AREA SO WILL
MAINTAIN DRY WX SUNDAY OVER BDE-BJI AREAS. DRY FOR SURE THE REST
OF THE FCST AREA SUNDAY.
NEXT SHORT WAVE SWINGING AROUND BASE OF TROUGH OVER THE PACIFIC
NORTHWEST TO MOVE INTO THE NRN PLAINS MONDAY WITH A BAND OF
SHOWERS AND PSBL THUNDER MOVING THRU. MOST OF SUN NIGHT LOOKS
DRY...SO DID PUSH BACK POPS A BIT TO MOSTLY 06Z MON AND
AFTERWARDS.
LONG TERM...MONDAY NIGHT THROUGH NEXT FRIDAY
MEDIUM-RANGE FORECAST MODELS STILL SHOWING BROAD 500 HPA TROUGH
ACROSS THE NORTHWEST AND NORTH-CENTRAL UNITED STATES EARLY NEXT
WEEK. THERE STILL EXIST DIFFERENCES IN THE DETAILS...BUT BOTH
GFS/ECMWF SHOW A PROLONGED WET PERIOD MONDAY/TUESDAY AND DIMINISHING
WEDNESDAY...AS MULTIPLE SHORT WAVES ROTATE THROUGH THE PARENT LOW.
AT THIS TIME...THURSDAY AND FRIDAY LOOK TO BE MAINLY DRY.
TEMPERATURES THROUGH THE PERIOD WILL GENERALLY BE AT OR SLIGHTLY
BELOW LATE SEPTEMBER NORMALS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG
[top]
000
FXUS63 KBIS 200137
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
837 PM CDT FRI SEP 19 2008
.UPDATE...
A BACK DOOR COLD FRONT IS PRESENTLY SLIDING THROUGH WESTERN AND
CENTRAL NORTH DAKOTA. 10 TO 15 KNOT WINDS ALONG THE PERIPHERY OF
A CANADIAN HIGH PRESSURE BEHIND THE FRONT ARE BEING OBSERVED...BUT
SHOULD GRADUALLY CALM OVER THE NEXT COUPLE OF HOURS. EARLIER
FORECAST LOOKS TO BE GOOD...SO UPDATES WERE VERY MINIMAL THIS
EVENING.
&&
.PREV DISCUSSION... /ISSUED 325 PM CDT FRI SEP 19 2008/
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
MAIN FORECAST PROBLEMS IN THE SHORT TERM WILL BE FIRE WEATHER
CONCERNS ON SATURDAY...THEN SHOWER AND THUNDERSTORM ACTIVITY LATE
THIS WEEKEND INTO EARLY NEXT WEEK. WILL UTILIZE A GFS/ECMWF BLEND
FOR DETAILS WITH THE FORECAST.
CURRENTLY...BACK DOOR COLD FRONT ACROSS NORTHERN NORTH DAKOTA. THIS
IS KEEPING NORTHERN ZONES COOLER THAN YESTERDAY. ACROSS THE
SOUTHWEST AND SOUTH CENTRAL...TEMPERATURES ARE WELL INTO THE 80S.
DIK HAS JUST TIED THEIR RECORD HIGH AND WILL LIKELY BREAK IT BY THE
TIME YOU FINISH READING THIS DISCUSSION. NEARLY FULL SUN ACROSS THE
STATE CURRENTLY...WITH ONLY SOME HIGH THIN CIRRUS. COLDER AIR WELL
BEHIND BACK DOOR FRONT IS PRODUCING SOME CLOUDINESS ACROSS SOUTHERN
SASKATCHEWAN AND MANITOBA. THIS WILL PUSH INTO NORTHERN NORTH DAKOTA
THROUGH THE REMAINDER OF THE AFTERNOON.
TONIGHT...WINDS WILL BECOME EASTERLY ACROSS ALL BUT THE FAR
SOUTHWEST TONIGHT BEFORE STALLING. NOT EXPECTING ANY PRECIPITATION
WITH THIS COLD FRONT...MAINLY JUST SOME MID LEVEL CLOUDINESS.
TEMPERATURES IN THE NORTHEAST CWA WILL BE A LITTLE COOLER TONIGHT.
FORECAST SOUNDINGS SHOW WINDS PICKING UP NICELY OVERNIGHT TONIGHT.
ON SATURDAY...WINDS WILL CONTINUE TO INCREASE AS AN APPROACHING
UPPER LEVEL TROUGH AND ASSOCIATED SURFACE SYSTEM PUSH THROUGH THE
NORTHERN ROCKIES AND HIGH PLAINS. STRONG SOUTHEAST GRADIENT WINDS
ARE EXPECTED OVER THE SOUTHWEST BY AFTERNOON. REST OF THE CWA WILL
SEE INCREASING AFTERNOON WINDS. TEMPERATURES WILL BE NOTICEABLY
COOLER OVER THE NORTHEAST...WHILE THE FAR SOUTHWEST WILL SEE
TEMPERATURES ABOUT THE SAME AS TODAY. LIKELY OVER A 20 DEGREE SPREAD
BETWEEN TEMPS IN THE NORTHEAST AND SOUTHWEST. NOT EXPECTING ANY
PRECIP ON SATURDAY AS WARM TEMPERATURES REMAIN ALOFT AN THUS STRONG
CAPPING WILL BE IN PLACE.
SATURDAY NIGHT...SURFACE LOW AND NEGATIVELY TILTED UPPER TROUGH INCH
CLOSER. ADJUSTED MINIMUM TEMPERATURES UP A BIT WITH THERMAL RIDGE
MOVING INTO THE AREA.
ON SUNDAY AND SUNDAY NIGHT...THE UPPER TROUGH LIFTS NORTH-NORTHEAST
INTO CANADA AND SURFACE SYSTEM REACHES WESTERN FORECAST AREA. LOOKS
LIKE A DECENT CHANCE OF SHOWERS AND THUNDERSTORMS OVER EASTERN
MONTANA...WITH THE ACTIVITY PUSHING INTO WESTERN NORTH DAKOTA IN THE
AFTERNOON. HAVE RAISED POPS A BIT ON SUNDAY AND SUNDAY NIGHT. AND
ALSO RAISED TEMPERATURES WITH THERMAL RIDGE REMAINING OVER THE
AREA.
MONDAY AND MONDAY NIGHT...ANOTHER IMPULSE MOVES THROUGH THE MEAN
UPPER TROUGH AS IT PUSHES SLOWLY INTO THE NORTHERN PLAINS. HAVE KEPT
POPS SIMILAR TO PREVIOUS FORECAST WITH BROAD BRUSH SLIGHT CHANCE TO
CHANCE POPS. DEFINITELY REMAINS UNSETTLED AND WOULD EXPECT A PERIOD
OF HIGHER POPS SOMEWHERE IN THIS TIME FRAME...BUT TO FAR OUT TO TRY
TO PIN DOWN FOR NOW.
LONG TERM...TUESDAY THROUGH FRIDAY...
NOT MANY CHANGES IN THE EXTENDED...THE GFS IS STILL FASTER WITH THE
PROGRESSION OF THE UPPER TROUGH MOVING THROUGH TUESDAY AND
WEDNESDAY. HENCE HAVE BLENDED THE TWO SOLUTIONS AND CONTINUED THE
CHANCE PRECIP WORDING TUESDAY AND TUESDAY NIGHT THEN DECREASING TO
SLIGHT CHANCE WEDNESDAY AND WEDNESDAY NIGHT. BOTH MODELS AGREE ON A
ZONAL FLOW SETTING UP THURSDAY AND FRIDAY. ANY SHORTWAVES RIGHT NOW
WOULD BE HARD TO TIME BEYOND WEDNESDAY NIGHT SO HAVE LEFT THE
FORECAST AS IS...WHICH IS DRY FOR NOW. TEMPERATURES COOLING THROUGH
THE LONG TERM TO NEAR SEASONAL LEVELS WITH HIGHS 65 TO 70 WEDS-FRI.
OVERNIGHT LOWS MAINLY IN THE 40S.
AVIATION...SCT TO BKN MID/HIGH CLOUDS NEXT 24HRS. VFR CONDITIONS
WITH CLOUD BASES RANGING FROM 12KFT TO 250KFT.
FIRE WEATHER...INCREASING SOUTH TO SOUTHEAST WINDS TO 30 MPH AND
MINIMUM RH`S IN THE UPPER TEENS WILL BE SUFFICIENT FOR EXTREME FIRE
WEATHER OVER SOUTHWEST AND WEST CENTRAL NORTH DAKOTA ON SATURDAY
AFTERNOON AND SATURDAY NIGHT. WILL CONTINUE THE FIRE WEATHER WATCH
FOR SOUTHWEST AND WEST CENTRAL NORTH DAKOTA SATURDAY AFTERNOON AND
EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR NDZ017-018-031>033-040-041-043-044.
&&
$$
TWH/KS/SCHECK
000
FXUS63 KBIS 192023
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
325 PM CDT FRI SEP 19 2008
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
MAIN FORECAST PROBLEMS IN THE SHORT TERM WILL BE FIRE WEATHER
CONCERNS ON SATURDAY...THEN SHOWER AND THUNDERSTORM ACTIVITY LATE
THIS WEEKEND INTO EARLY NEXT WEEK. WILL UTILIZE A GFS/ECWMF BLEND
FOR DETAILS WITH THE FORECAST.
CURRENTLY...BACK DOOR COLD FRONT ACROSS NORTHERN NORTH DAKOTA. THIS
IS KEEPING NORTHERN ZONES COOLER THAN YESTERDAY. ACROSS THE
SOUTHWEST AND SOUTH CENTRAL...TEMPERATURES ARE WELL INTO THE 80S.
DIK HAS JUST TIED THEIR RECORD HIGH AND WILL LIKELY BREAK IT BY THE
TIME YOU FINISH READING THIS DISCUSSION. NEARLY FULL SUN ACROSS THE
STATE CURRENTLY...WITH ONLY SOME HIGH THIN CIRRUS. COLDER AIR WELL
BEHIND BACK DOOR FRONT IS PRODUCING SOME CLOUDINESS ACROSS SOUTHERN
SASKATCHEWAN AND MANITOBA. THIS WILL PUSH INTO NORTHERN NORTH DAKOTA
THROUGH THE REMAINDER OF THE AFTERNOON.
TONIGHT...WINDS WILL BECOME EASTERLY ACROSS ALL BUT THE FAR
SOUTHWEST TONIGHT BEFORE STALLING. NOT EXPECTING ANY PRECIPITATION
WITH THIS COLD FRONT...MAINLY JUST SOME MID LEVEL CLOUDINESS.
TEMPERATURES IN THE NORTHEAST CWA WILL BE A LITTLE COOLER TONIGHT.
FORECAST SOUNDINGS SHOW WINDS PICKING UP NICELY OVERNIGHT TONIGHT.
ON SATURDAY...WINDS WILL CONTINUE TO INCREASE AS AN APPROACHING
UPPER LEVEL TROUGH AND ASSOCIATED SURFACE SYSTEM PUSH THROUGH THE
NORTHERN ROCKIES AND HIGH PLAINS. STRONG SOUTHEAST GRADIENT WINDS
ARE EXPECTED OVER THE SOUTHWEST BY AFTERNOON. REST OF THE CWA WILL
SEE INCREASING AFTERNOON WINDS. TEMPERATURES WILL BE NOTICEABLY
COOLER OVER THE NORTHEAST...WHILE THE FAR SOUTHWEST WILL SEE
TEMPERATURES ABOUT THE SAME AS TODAY. LIKELY OVER A 20 DEGREE SPREAD
BETWEEN TEMPS IN THE NORTHEAST AND SOUTHWEST. NOT EXPECTING ANY
PRECIP ON SATURDAY AS WARM TEMPERATURES REMAIN ALOFT AN THUS STRONG
CAPPING WILL BE IN PLACE.
SATURDAY NIGHT...SURFACE LOW AND NEGATIVELY TILTED UPPER TROUGH INCH
CLOSER. ADJUSTED MINIMUM TEMPERATURES UP A BIT WITH THERMAL RIDGE
MOVING INTO THE AREA.
ON SUNDAY AND SUNDAY NIGHT...THE UPPER TROUGH LIFTS NORTH-NORTHEAST
INTO CANADA AND SURFACE SYSTEM REACHES WESTERN FORECAST AREA. LOOKS
LIKE A DECENT CHANCE OF SHOWERS AND THUNDERSTORMS OVER EASTERN
MONTANA...WITH THE ACTIVITY PUSHING INTO WESTERN NORTH DAKOTA IN THE
AFTERNOON. HAVE RAISED POPS A BIT ON SUNDAY AND SUNDAY NIGHT. AND
ALSO RAISED TEMPERATURES WITH THERMAL RIDGE REMAINING OVER THE
AREA.
MONDAY AND MONDAY NIGHT...ANOTHER IMPULSE MOVES THROUGH THE MEAN
UPPER TROUGH AS IT PUSHES SLOWLY INTO THE NORTHERN PLAINS. HAVE KEPT
POPS SIMILAR TO PREVIOUS FORECAST WITH BROADBRUSH SLIGHT CHANCE TO
CHANCE POPS. DEFINITELY REMAINS UNSETTLED AND WOULD EXPECT A PERIOD
OF HIGHER POPS SOMEWHERE IN THIS TIME FRAME...BUT TO FAR OUT TO TRY
TO PIN DOWN FOR NOW.
.LONG TERM...TUESDAY THROUGH FRIDAY...
NOT MANY CHANGES IN THE EXTENDED...THE GFS IS STILL FASTER WITH THE
PROGRESSION OF THE UPPER TROUGH MOVING THROUGH TUESDAY AND
WEDNESDAY. HENCE HAVE BLENDED THE TWO SOLUTIONS AND CONTINUED THE
CHANCE PRECIP WORDING TUESDAY AND TUESDAY NIGHT THEN DECREASING TO
SLIGHT CHANCE WEDNESDAY AND WEDNESDAY NIGHT. BOTH MODELS AGREE ON A
ZONAL FLOW SETTING UP THURSDAY AND FRIDAY. ANY SHORTWAVES RIGHT NOW
WOULD BE HARD TO TIME BEYOND WEDNESDAY NIGHT SO HAVE LEFT THE
FORECAST AS IS...WHICH IS DRY FOR NOW. TEMPERATURES COOLING THROUGH
THE LONG TERM TO NEAR SEASONAL LEVELS WITH HIGHS 65 TO 70 WEDS-FRI.
OVERNIGHT LOWS MAINLY IN THE 40S.
&&
.AVIATION...SCT TO BKN MID/HIGH CLOUDS NEXT 24HRS. VFR CONDITIONS
WITH CLOUD BASES RANGING FROM 12KFT TO 250KFT.
&&
.FIRE WEATHER...INCREASING SOUTH TO SOUTHEAST WINDS TO 30 MPH AND
MINIMUM RH`S IN THE UPPER TEENS WILL BE SUFFICIENT FOR EXTREME FIRE
WEATHER OVER SOUTHWEST AND WEST CENTRAL NORTH DAKOTA ON SATURDAY
AFTERNOON AND SATURDAY NIGHT. WILL CONTINUE THE FIRE WEATHER WATCH
FOR SOUTHWEST AND WEST CENTRAL NORTH DAKOTA SATURDAY AFTERNOON AND
EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR NDZ017-018-031>033-040-041-043-044.
&&
$$
TWH/KS
000
FXUS63 KFGF 191955
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
255 PM CDT FRI SEP 19 2008
.SHORT TERM...
FCST CONCERNS ARE MAINLY TEMPS THIS WEEKEND THEN PCPN CHANCES
NEXT WEEK.
FIRST OFF...SHORT WAVE TROUGH NOTED BY 12Z GFS MODEL FROM FAR NW
WISCONSIN INTO ECNTRL SD WITH NARROW AXIS OF INSTABILITY AND SCT
TSTMS ALONG IT. THIS FEATURE WILL EVENTUALLY GET SWEEPED SOUTH AND
EAST AS MAIN COLD FRONT SWEEPS THROUGH TONIGHT.
THAT COLD FRONT WAS LOCATED FROM LOW PRESSURE OVER HUDSON BAY
SOUTHWEST TO JUST SOUTH OF BAUDETTE TO CROOKSTON TO MAYVILLE THEN
BACK TO NEAR MINOT. MORE OF A NORTH WIND BEHIND THE FRONT...BUT
SFC TEMPS STILL MILD WITH COOLER SFC AIR LOCATED WELL NORTH OF
FRONT NORTH OF A SASKATOON TO DAUPHIN TO RED LAKE ONTARIO LINE.
SFC HIGH NOTED IN NRN SASK WILL DROP QUICKLY SOUTHEAST INTO NW
ONTARIO SATURDAY WITH TIGHT 850 MB BAROCLINIC ZONE DEVELOPING FROM
NORTHEAST TO SOUTHWEST ACROSS THE FCST AREA. 850 MB TEMPS SATURDAY
PROGGED IN THE +2-4C RANGE NORTHEAST TO +14C RANGE SOUTHWEST AT
18Z SATURDAY WITH 925 MB TEMPS FROM +6C TO +16C. EXTRAPOLATION OF SFC
TEMPS UNDERNEATH SIMILAR TEMP RANGES IN SASK WOULD INDICATE TIGHT
HIGH TEMP GRADIENT WITH 55-58 AT FLAG ISLAND TO MID 60S AT DVL-
GFK-BJI TO 70 AT FARGO TO MID 70S FAR SOUTHWEST CORNER OF FCST
AREA (JMS-ABR). NAM AND MET MOS HAS BEEN THE COLDER TEMP-WISE
WHILE GFS/MAV MOS THE WARMER SOLN. USING A SOLN BETWEEN THE TWO
FOR TEMPS HAS WORKED OUT WELL RECENTLY AND CONTINUED TO DO SO FOR
TEMPS THIS WEEKEND. AS FOR CLOUD COVER...MODELS INDICATE A RIBBON
OF MID LEVEL MOISTURE TO SPREAD FROM NRN ALBERTA INTO SRN SASK
INTO NE ND/NRN MN TONIGHT INTO SATURDAY BEFORE BEING PUSHED EAST.
THIS LOOKS REASONABLE BASED ON UPSTREAM OBS SHOWING SCT-BKN MID
CLOUDS IN THE EDMONTON-SASKATOON AREAS.
HIGH WILL SLIDE EAST OF THE AREA SAT NIGHT WITH RETURN FLOW
SETTING UP QUICKLY OVER ERN ND PREVENT LARGE TEMP DROP WITH
COOLEST TEMPS AND LIGHTER WINDS OVER BDE-BJI AREAS...BUT EVEN
THERE ENOUGH OF A GRADIENT DEVELOPING TO KEEP TEMPS 40-45..SO
DESPITE CHILLY AIRMASS MOVING DOWN...IT MOVES OUT QUICK ENOUGH TO
PREVENT ANY FROST. SOUTHEAST WINDS AND WARM ADV ROAR INTO THE AREA
SUNDAY...UPPING TEMPS A GOOD 10 DEGREES OVER SATURDAY. NOSE OF
850-700 MB WARM ADVECTION COMBINED WITH 700 MOISTURE MAY PRODUCE A
FEW SHOWERS OR ISOLD THUNDER OVER NE MN SUNDAY...BUT LATEST MODEL
GUIDANCE SUGGEST THIS WILL BE EAST OF THE FCST AREA SO WILL
MAINTAIN DRY WX SUNDAY OVER BDE-BJI AREAS. DRY FOR SURE THE REST
OF THE FCST AREA SUNDAY.
NEXT SHORT WAVE SWINGING AROUND BASE OF TROUGH OVER THE PACIFIC
NORTHWEST TO MOVE INTO THE NRN PLAINS MONDAY WITH A BAND OF
SHOWERS AND PSBL THUNDER MOVING THRU. MOST OF SUN NIGHT LOOKS
DRY...SO DID PUSH BACK POPS A BIT TO MOSTLY 06Z MON AND
AFTERWARDS.
.LONG TERM...MONDAY NIGHT THROUGH NEXT FRIDAY
MEDIUM-RANGE FORECAST MODELS STILL SHOWING BROAD 500 HPA TROUGH
ACROSS THE NORTHWEST AND NORTH-CENTRAL UNITED STATES EARLY NEXT
WEEK. THERE STILL EXIST DIFFERENCES IN THE DETAILS...BUT BOTH
GFS/ECMWF SHOW A PROLONGED WET PERIOD MONDAY/TUESDAY AND DIMINISHING
WEDNESDAY...AS MULTIPLE SHORT WAVES ROTATE THROUGH THE PARENT LOW.
AT THIS TIME...THURSDAY AND FRIDAY LOOK TO BE MAINLY DRY.
TEMPERATURES THROUGH THE PERIOD WILL GENERALLY BE AT OR SLIGHTLY
BELOW LATE SEPTEMBER NORMALS.
&&
.AVIATION...
EXPECT VFR CONDITIONS TO PERSIST AT ALL TAF SITES THE NEXT 24 HOURS.
A COLD FRONT WILL DROP SOUTH FROM CANADA AND ACROSS THE RED RIVER
VALLEY THIS EVENING AND OVERNIGHT...RESULTING IN A SURFACE WIND
SHIFT TO THE NORTH-NORTHEAST. CLOUDS WILL BE MINIMAL WITH ONLY
SCATTERED DECKS AT OR ABOVE 15000 FEET.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/ROGERS
000
FXUS63 KFGF 191607
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1107 AM CDT FRI SEP 19 2008
.UPDATE...
ISSUE IS TEMPS TODAY. STILL WARM TODAY...WITH COLD FRONT AND
STRONG 850 MB COLD ADVECTION ARRIVING IN THE FAR NORTH MID AFTN
AND SPREADING SOUTH THROUGH LATE EVE. INITIAL WIND SHIFT TO THE
NORTHWEST NOT ASSOC WITH MUCH COOLING WITH MAIN COOLING BEHIND
WIND SHIFT TO THE DUE NORTH BUT THAT WILL NOT OCCUR UNTIL A FEW
HOURS AFTER INITIAL NORTHWEST WIND SHIFT. THAT SAID...WARM AIR AHD
OF MAIN COLD PUSH OVER THE AREA TODAY WITH HIGHS INTO THE LOWER
80S VERY REASONABLE OVER SE ND INTO PARTS OF NW MN WITH 70S
ELSEWHERE. MID LEVEL SHORT WAVE MOVING THRU NRN MN ATTM WITH
TROUGH FROM THE MN ARROWHEAED INTO WCNTRL MN. CONVECTION ALONG
THIS LINE EXITING TO EAST OF THE FCST AREA AND NO MORE PCPN
EXPECTED TODAY.
&&
.AVIATION...
THREAT FOR THUNDERSTORMS IN BJI TAF AREA HAS ENDED...WITH SOME
SOME PATCHY AC/CI THRU 00Z FOR THE FCST AREA. MAIN WIND SHIFT TO
THE NORTH WILL OCCUR THIS AFTN IN THE FAR NORTH AND EARLY EVE IN
THE SOUTH.
&&
.PREV DISCUSSION... /ISSUED 240 AM CDT FRI SEP 19 2008/
DISCUSSION...
FORECAST CHALLENGE CONCERNS MAINLY TEMPERATURES AND PCPN
CHANCES...ESPECIALLY IN LATER PERIODS. MAIN MODEL DIFFERENCES
CONCERNS DEGREE OF COOLING ON SATURDAY. GFS/MAV HAS PERFORMED WELL
SO WILL CONTINUE TO UTILIZE FOR DETAILS.
IN THE NEAR TERM ISOLD CONVECTION CONTINUES ACROSS FAR SE ND AHEAD
OF SURFACE BOUNDARY IN ZONE OF GREATER INSTABILITY AND DEEPER
LAYERED RH. SOUTH END OF BOUNDARY WILL BE SLOW MOVING AND BY 12Z ANY
INSTABILITY WILL BE CONFINED TO FAR SE FA. CURRENT TIMING PUTS
CURRENT CONVECTION OVER FAR SE FA AND WILL MENTION ISOLD T OVER THIS
AREA THIS MORNING.
FOR REMAINDER OF DAY PREFRONTAL TROUGH WILL CONTINUE TO SHIFT EAST
BEING OVERTAKEN BY TRUE COLD FRONT WHICH ENTERS FAR NORTHERN FA THIS
AFTERNOON. COLUMN DRIES DURING DAY IN WAKE OF TROUGH PASSAGE SO AM
NOT ANTICIPATING ANY PCPN REDEVELOPMENT WITH COLD FRONT. THERMAL
RIDGE SAGS TO FAR SOUTHERN FA BY LATE AFTERNOON AND WILL SEE WARMEST
TEMPERATURES. FAR NORTHERN FA WILL BE ABOUT 10 DEGREES COOLER BEING
IN STRONGEST COLD ADVECTION.
STRONGEST COLD ADVECTION OVERNIGHT MAKES A GLANCING BLOW TO NE
QUARTER OF FORECAST AREA AND WILL TRIM TEMPERATURES MOST IN THIS
AREA. SURFACE GRADIENT FROM DESCENDING HIGH PRESSURE MAY LIMIT
TEMPERATURES FROM DROPPING TOO FAR.
TEMPERATURES WILL BE A CHALLENGE FOR SATURDAY/SATURDAY NIGHT AS
NUMERICAL GUIDANCE OFF BY ABOUT 10 DEGREES. AM EXPECTING SOME SOLAR
DURING DAY AND WARM ADVECTION GETS GOING IN THE AFTERNOON AS RETURN
FLOW BECOMES ESTABLISHED. WITH MAV PERFORMING REAL WELL PAST FEW
DAYS WILL LEAN TEMPERATURES CLOSER BUT A LITTLE COOLER TO MAV VALUES.
WITH MIXING AND WARM ADVECTION SUNDAY NIGHT WILL CONTINUE TO TREND
MINIMUM TEMPERATURES CLOSER TO WARMER MAV VALUES.
MODELS TO A DEGREE PAINTING SOME LIGHT QPF OVER NW MN DURING DAY
SUNDAY WITH PASSAGE OF WARM ADVECTION MAXIMA. WITH SHORT WAVE RIDGE
OVER AREA SUNDAY DO NOT FEEL THERE WILL BE MUCH FOR UPPER SUPPORT
AND NOT MUCH IN THE WAY OF SURFACE FORCING. WILL KEEP FORECAST DRY
FOR NOW BUT MAY NEED TO BE ADDRESSED DOWN THE ROAD. OTHERWISE
TEMPERATURES WILL RECOVER AHEAD OF NEXT WAVE.
ABOVE MENTIONED WAVE PUSHES INTO THE DAKOTAS FIRST PART OF NEXT
WEEK. WITH EVOLVING SW MID LEVEL FLOW AND WAVE RIDING THROUGH WILL
KEEP POPS GOING INTO MIDWEEK.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/VOELKER
000
FXUS63 KBIS 190839
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
326 AM CDT FRI SEP 19 2008
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
WEAK SHORTWAVE ENERGY WILL MOVE THROUGH THE STATE TODAY. THIS WILL
ALLOW A WEAK BACK DOOR COLD FRONT TO SLIDE INTO THE STATE TONIGHT
AND RETURN AS A WARM FRONTAL BOUNDARY ON SATURDAY INTO SUNDAY AS
UPPER LOW OVER THE WEST COAST MOVES INTO THE NORTHERN PLAINS BY THE
END OF THE WEEKEND. EXPECT THIS FRONTAL SYSTEM TO HAVE LITTLE
WEATHER ASSOCIATED WITH IT OTHER THAN TO BRING A FEW DEGREES OF
COOLING TO THE STATE...WITH THE NORTHERN BORDER REGIONS COOLING
MORE. SHOULD SEE UPPER 80S/AROUND 90 SOUTHWEST TO AROUND 80 NORTH
CENTRAL TODAY...THIS WILL COOL TO THE 70S NORTH ON SATURDAY BUT
REMAIN IN THE MID 80S SOUTHWEST. WITH INCREASING PRESSURE GRADIENT
EXPECT SOUTHEAST WINDS OF 25 TO 30 MPH ACROSS THE SOUTHWEST
SATURDAY. WITH RELATIVE HUMIDITIES IN THE UPPER TEENS THERE HAVE
CHOSEN TO ISSUE FIRE WEATHER WATCH SATURDAY AFTERNOON AND EVENING.
WITH APPROACHING UPPER LOW/SHORTWAVE AND ASSOCIATED COLD FRONT ON
SUNDAY...EXPECT BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS.
.LONG TERM...MONDAY THROUGH FRIDAY.
WEATHER TO BECOME MORE UNSETTLED IN EXTENDED PERIODS WITH UPPER LOW
MOVING ONSHORE TO NORTH CENTRAL CANADA BY END OF EXTENDED. LEAD
SHORTWAVE AHEAD OF TROUGH WILL BE PUSHING ONTO NORTHERN PLAINS AT
BEGINNING OF UPCOMING WORKWEEK WITH CONVECTION LIKELY ONGOING.
SCATTERED CONVECTION WILL CONTINUE TUESDAY AND WEDNESDAY BEFORE FLAT
RIDGE REBUILDS OVER PACIFIC NORTHWEST AGAIN LATE IN WEEK. RIDGE
SLIGHTLY MORE PRONOUNCED ON ECMWF AND ADDED LOW POPS WITH NO WX FOR
NEW DAY 8. TEMPERATURES COOL TO NEAR NORMAL VALUES.
&&
.AVIATION...
WEAK CONVECTION SOUTHEAST OF TAF SITES ONLY CONCERN FOR TODAYS TAFS
AND WILL KEEP VFR CONDS THROUGHOUT THE PERIOD.
&&
.FIRE WEATHER...INCREASING SOUTH TO SOUTHEAST WINDS TO 30 MPH AND
MINIMUM RH`S IN THE UPPER TEENS WILL BE SUFFICIENT FOR EXTREME FIRE
WEATHER OVER SOUTHWEST AND WEST CENTRAL NORTH DAKOTA ON SATURDAY
AFTERNOON AND SATURDAY NIGHT. HAVE ISSUED A FIRE WEATHER WATCH FOR
SOUTHWEST AND WEST CENTRAL NORTH DAKOTA SATURDAY AFTERNOON AND
EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR NDZ017-018-031>033-040-041-043-044.
&&
$$
WAA/HW
000
FXUS63 KFGF 190744
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
240 AM CDT FRI SEP 19 2008
.DISCUSSION...
FORECAST CHALLENGE CONCERNS MAINLY TEMPERATURES AND PCPN
CHANCES...ESPECIALLY IN LATER PERIODS. MAIN MODEL DIFFERENCES
CONCERNS DEGREE OF COOLING ON SATURDAY. GFS/MAV HAS PERFORMED WELL
SO WILL CONTINUE TO UTILIZE FOR DETAILS.
IN THE NEAR TERM ISOLD CONVECTION CONTINUES ACROSS FAR SE ND AHEAD
OF SURFACE BOUNDARY IN ZONE OF GREATER INSTABILITY AND DEEPER
LAYERED RH. SOUTH END OF BOUNDARY WILL BE SLOW MOVING AND BY 12Z ANY
INSTABILITY WILL BE CONFINED TO FAR SE FA. CURRENT TIMING PUTS
CURRENT CONVECTION OVER FAR SE FA AND WILL MENTION ISOLD T OVER THIS
AREA THIS MORNING.
FOR REMAINDER OF DAY PREFRONTAL TROUGH WILL CONTINUE TO SHIFT EAST
BEING OVERTAKEN BY TRUE COLD FRONT WHICH ENTERS FAR NORTHERN FA THIS
AFTERNOON. COLUMN DRIES DURING DAY IN WAKE OF TROUGH PASSAGE SO AM
NOT ANTICIPATING ANY PCPN REDEVELOPMENT WITH COLD FRONT. THERMAL
RIDGE SAGS TO FAR SOUTHERN FA BY LATE AFTERNOON AND WILL SEE WARMEST
TEMPERATURES. FAR NORTHERN FA WILL BE ABOUT 10 DEGREES COOLER BEING
IN STRONGEST COLD ADVECTION.
STRONGEST COLD ADVECTION OVERNIGHT MAKES A GLANCING BLOW TO NE
QUARTER OF FORECAST AREA AND WILL TRIM TEMPERATURES MOST IN THIS
AREA. SURFACE GRADIENT FROM DESCENDING HIGH PRESSURE MAY LIMIT
TEMPERATURES FROM DROPPING TOO FAR.
TEMPERATURES WILL BE A CHALLENGE FOR SATURDAY/SATURDAY NIGHT AS
NUMERICAL GUIDANCE OFF BY ABOUT 10 DEGREES. AM EXPECTING SOME SOLAR
DURING DAY AND WARM ADVECTION GETS GOING IN THE AFTERNOON AS RETURN
FLOW BECOMES ESTABLISHED. WITH MAV PERFORMING REAL WELL PAST FEW
DAYS WILL LEAN TEMPERATURES CLOSER BUT A LITTLE COOLER TO MAV VALUES.
WITH MIXING AND WARM ADVECTION SUNDAY NIGHT WILL CONTINUE TO TREND
MINIMUM TEMPERATURES CLOSER TO WARMER MAV VALUES.
MODELS TO A DEGREE PAINTING SOME LIGHT QPF OVER NW MN DURING DAY
SUNDAY WITH PASSAGE OF WARM ADVECTION MAXIMA. WITH SHORT WAVE RIDGE
OVER AREA SUNDAY DO NOT FEEL THERE WILL BE MUCH FOR UPPER SUPPORT
AND NOT MUCH IN THE WAY OF SURFACE FORCING. WILL KEEP FORECAST DRY
FOR NOW BUT MAY NEED TO BE ADDRESSED DOWN THE ROAD. OTHERWISE
TEMPERATURES WILL RECOVER AHEAD OF NEXT WAVE.
ABOVE MENTIONED WAVE PUSHES INTO THE DAKOTAS FIRST PART OF NEXT
WEEK. WITH EVOLVING SW MID LEVEL FLOW AND WAVE RIDING THROUGH WILL
KEEP POPS GOING INTO MIDWEEK.
&&
.AVIATION...
SOME BKN VFR CIGS EXPECTED WITH ISOLD T ACROSS EXTREME SE ND INTO
WEST CENTRAL MN THIS MORNING. REMAINDER OF FA SHOULD BE CIG FREE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER
000
FXUS63 KFGF 190136
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
836 PM CDT THU SEP 18 2008
.DISCUSSION...MAIN CHALLENGE OVERNIGHT WILL CONTINUE TO BE
CONVECTIVE POTENTIAL. NOTHING HAS BEEN ABLE TO DEVELOP AS OF YET
DUE TO STRONG CAP. WEAK RETURNS NEAR KBIS HAVE QUICKLY DISSIPATED.
EXPECT THIS TO BE THE TREND THROUGH MUCH OF THE NIGHT. MODELS SEEM
TO INDICATE INCREASED 700MB MOISTURE INTO THE S FA NEAR OR AFTER
06Z...WHICH MAY BE ENOUGH IN CONJUNCTION WITH 850MB WIND SHIFT FOR
A STORM OR TWO. WILL KEEP ISOLD THUNDER. FORECAST IN GOOD SHAPE
AND NO CHANGES NEEDED.
&&
.AVIATION...WEAK TROUGH HAS PASSED THRU DVL REGION WITH WIND SHIFT
TO THE WEST. THE TROUGH WILL MOVE INTO THE RED RIVER VALLEY AND NW
MN OVERNIGHT WITH SOUTH WINDS SHIFTING SOUTHWEST OR POSSIBLE WEST
FOR A TIME LATE TONIGHT INTO FRIDAY AHEAD OF COLD FRONT DUE TO
DROP THRU THE AREA FRI AFTN/EVE. CONVECTIVE POTENTIAL TONIGHT LOOKS
WEAK AND DID NOT MENTION IN TAFS. ISOLD COVERAGE AT BEST THROUGH 08Z
TIME PERIOD RED RIVER VALLEY INTO NORTHWEST MINNESOTA.
&&
.PREV DISCUSSION... /ISSUED 256 PM CDT THU SEP 18 2008/
SHORT TERM...TONIGHT THROUGH SUNDAY
MAIN FORECAST CHALLENGES INCLUDE PRECIPITATION CHANCES TONIGHT
INTO EARLY TOMORROW AND TEMPERATURES THROUGHOUT THE FORECAST
PERIOD. GFS AND NAM IN GOOD AGREEMENT...SO USED A MODEL BLEND FOR
THIS FORECAST PACKAGE. RELIED HEAVILY ON MAV/MAV_BC GUIDANCE FOR
TEMPERATURES...WHICH HAVE PERFORMED WELL THE PAST FEW DAYS.
19 UTC SURFACE ANALYSIS SHOWS TROUGH AXIS ACROSS THE WESTERN
DAKOTAS. ACTUAL SURFACE BOUNDARY APPEARS TO BE JUST WEST OF MINOT
STRETCHING TO THE SOUTHWEST CORNER OF NORTH DAKOTA AS EVIDENT BY
DEVELOPING TOWERING CUMULUS ON VISIBLE SATELLITE IMAGERY. MODELS
ARE IN GOOD AGREEMENT SHOWING THIS FEATURE MOVING EASTWARD ACROSS
NORTH DAKOTA LATE THIS AFTERNOON AND EVENING. STILL DECENT AMOUNT
OF INSTABILITY OUT AHEAD OF THE BOUNDARY LATE THIS AFTERNOON WITH
ML CAPE VALUES 1000-1500 J/KG AND SHOWALTER VALUES NEAR -5.
HOWEVER...CAP IS STRONG. NOT EXPECTING ANY CONVECTIVE DEVELOPMENT
UNTIL MESOSCALE FORCING FROM SURFACE BOUNDARY CAN HELP BREAK
THROUGH THE CONVECTIVE INHIBITION. BEST CHANCE FOR THIS TO HAPPEN
IS ACROSS SOUTHEAST NORTH DAKOTA...AND ALONG AND EAST OF THE RED
RIVER VALLEY AFTER 00 UTC TONIGHT. INSTABILITY WEAKENS DURING THIS
TIME AND 0-6 KM SHEAR IS AROUND 30 KTS OR LESS...SO SEVERE
POTENTIAL WILL BE LIMITED. EXPECT A FEW THUNDERSTORMS AT BEST.
DRY AND SLIGHTLY COOLER WEATHER RETURNS FOR FRIDAY AS SURFACE HIGH
PRESSURE BUILDS SOUTHEASTWARD FROM CANADA...ALTHOUGH TEMPERATURES WILL
STILL BE WELL ABOVE SEASONAL NORMALS FOR MID-SEPTEMBER. SOME AREAS
ACROSS THE SOUTHERN RED RIVER VALLEY MAY ONCE AGAIN TOP 80
DEGREES. WINDS WILL BE LESS THAN TODAY...GENERALLY FROM THE WEST-
NORTHWEST.
ATTENTION THEN TURNS TO ANOTHER COLD FRONT FROM CANADA FRIDAY
NIGHT INTO EARLY SATURDAY. MOISTURE LOOKS TO BE LIMITED WITH THIS
FEATURE...SO MAIN IMPACT WILL BE DECREASING TEMPERATURES SATURDAY.
EXPECT FAIRLY STRONG THERMAL GRADIENT FROM NORTH TO SOUTH...WITH
AREAS ACROSS THE NORTH IN THE MID 60S AND AREAS TO THE SOUTH IN
THE MID 70S. TEMPERATURES FORECAST TO REBOUND SLIGHTLY ON
SUNDAY...REMAINING DRY THROUGH THE REMAINDER OF THE WEEKEND.
LONG TERM...SUNDAY NIGHT THROUGH NEXT THURSDAY
500 MB TROUGH WILL MOVE EAST INTO THE PACIFIC NORTHWEST OVER THE
WEEKEND WITH THE FIRST SHORT WAVE ROUNDING THE BASE OF THE TROUGH
AND MOVING INTO THE NRN PLAINS MONDAY...WITH A MORE POTENT ONE
MOVING THRU TUES-EARLY WED. 12Z MODEL RUNS HAVE SHOWN PRETTY GOOD
CONTINUITY REGARDING THIS TREND AND THUS LITTLE CHANGE NEEDED TO
EXTENDED WITH CHC POPS LATE SUNDAY INTO WEDNESDAY. PER COORDINATION
WITH NEIGHBORING OFFICES DID GO DRY ON THURSDAY AS FRONT WELL EAST
OF THE AREA DESPITE LOW CHC POPS GIVEN BY HPC GUIDANCE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG
000
FXUS63 KBIS 182027
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
327 PM CDT THU SEP 18 2008
.SHORT TERM...
THE MAIN FORECAST CHALLENGE FOR TONIGHT RESIDES UPON CONVECTIVE
CHANCES ACROSS THE SOUTH CENTRAL AND SOUTHEAST...IN ADDITION TO LOW
TEMPERATURES AND FROST FOR TONIGHT ACROSS THE WEST.
MID TO UPPER 50S DEW POINTS AND TEMPERATURES IN THE MID 80S TO NEAR
90 AHEAD OF A SURFACE TROUGH AXIS FROM MINOT TO RAPID CITY HAS
YIELDED SURFACE BASED CAPE VALUES OF AOA 1000 J/KG AHEAD OF THE
TROUGH. HOWEVER...850MB WARM AIR ADVECTION HAS PLACED A CAP IN THE
850 TO 775MB LAYER OVER MUCH OF SOUTH CENTRAL AND SOUTHEASTERN NORTH
DAKOTA. BUFR SOUNDINGS INDICATE THAT THE CAP IS STRONGEST OVER THE
JAMES RIVER VALLEY WITH SOME WEAKENING EXPECTED OVER THE SOUTH
CENTRAL AND SOUTHWESTERN PORTIONS OF THE STATE IN THE 21Z-00Z
TIME FRAME WITH ENHANCED MOISTURE FLUX CONVERGENCE. 12Z KBIS SOUNDING
INDICATES DRY ADIABATIC MID LEVEL LAPSES DO EXIST ABOVE THE CAP.
THEREFORE...ISOLATED CELLS ARE POSSIBLE LATE THIS AFTERNOON ACROSS
SOUTHWEST SOUTH CENTRAL ND IN LOCATIONS THAT ARE ABLE TO REACH
CONVECTIVE TEMPERATURES AIDED BY A WEAK SHORTWAVE PROGGED TO REACH
CENTRAL NORTH DAKOTA BY 00Z THIS EVENING. 25 KTS OF DEEP LAYER SHEAR
AND STRONG MID LEVEL LAPSE RATES SUGGEST A ISOLATED HAIL THREAT WITH
ANY CELLS THAT ARE ABLE TO DEVELOP...HOWEVER THE THREAT WILL REMAIN
SHORT LIVED. ELEVATED CONVECTION WILL CONTINUE TONIGHT ACROSS THE
EXTREME SOUTHEAST PORTIONS OF THE CWA IN A STRENGTHENING LOW LEVEL
JET/WARM AIR ADVECTION REGIME WITH AOA 1000 J/KG OF 850MB BASED
CAPE...SHOWALTER VALUES TO -5C AND STRONG MID LEVEL LAPSE.
MID TO UPPER 30S DEWPOINTS CURRENTLY IN CENTRAL MONTANA ARE PROGGED
TO ADVECT INTO WESTERN NORTH DAKOTA TONIGHT. WITH EXPECTED CLEAR
SKIES AND LIGHT WINDS...STRONG LOW LEVEL RADIATIONAL COOLING IS
EXPECTED...ESPECIALLY ACROSS THE TERRAIN OF THE WEST. MORNING LOW
TEMPERATURES ACROSS THE WEST TODAY REVEAL A LOW OF 41 AT HETTINGER
AND 44 AT DICKINSON...WITH DEWPOINTS IN THE LOW 40S AND NEARLY
SATURATED RELATIVE HUMIDITY VALUES...INDICATING THE POTENTIAL FOR
FURTHER COOLING IN THE PRESENCE OF DRIER AIR. THEREFORE...HAVE
REDUCED THE OVERNIGHT LOW TEMPERATURES IN THE WEST INTO THE MID TO
UPPER 30S AND HAVE ADDED PATCHY FROST WORDING. WILL ALLOW EVENING
SHIFT TO MONITOR THE ADVECTION OF DRY AIR AND THERMAL TRENDS TO
ASCERTAIN IF A FROST ADVISORY WILL BE NECESSARY FOR TONIGHT ACROSS
THE WEST.
A COLD FRONT AHEAD OF SURFACE HIGH PRESSURE WILL ENTER NORTHERN
NORTH DAKOTA FRIDAY MORNING AND WILL BE APPROXIMATELY ON A LIGNITE
TO MCCLUSKY TO FORMAN LINE BY 18Z FRIDAY. NAM IS MUCH MORE
PROGRESSIVE WITH PROPAGATING THE COLD FRONT FURTHER SOUTH COMPARED
TO THE GFS. HAVE DECIDED TO TREND TOWARDS THE GFS...SUPPORTED BY THE
ECMWF...WHICH WOULD GIVE THE ROLLA AREA A HIGH OF 75. HOWEVER...THE
THERMAL FIELDS ACROSS THE SOUTH CENTRAL...WEST AND SOUTHEAST WILL
SEE A SLIGHT INCREASE FRIDAY COMPARED TO THURSDAY...WITH HIGHS
CLIMBING INTO THE LOW 90S IN THE SOUTHWEST AND SOUTH CENTRAL.
HIGH PRESSURE WILL PROPAGATE INTO THE GREAT LAKES DURING THE DAY ON
SATURDAY...PROMOTING SOUTHERLY FLOW AND A SLOW RETREAT OF THE
FRONTAL BOUNDARY INTO SOUTHERN CANADA BY EVENING. A FEW MID LEVEL
CLOUD DECKS ARE POSSIBLE ALONG THE BAROCLINIC ZONE ASSOCIATED WITH
THE FRONT ON SATURDAY...HOWEVER...A DRY LOWER ATMOSPHERE WILL
PREVENT ANY SHOWER DEVELOPMENT. TEMPERATURES WILL ONLY CLIMB INTO
THE UPPER 60S NORTH OF THE BOUNDARY IN FAR NORTH CENTRAL NORTH
DAKOTA...WITH HIGHS TO THE SOUTH OF THE BOUNDARY 3-4 DEGREES COOLER
THAN VALUES SEEN ON FRIDAY WITH WEAK COLD AIR ADVECTION OUT OF THE
GREAT LAKES HIGH. WINDS WILL BE BREEZY ON SATURDAY ACROSS THE
SOUTHWEST WITH A LOW LEVEL ADIABATIC LAYER AND 20 TO 25 KTS TO MIX.
A 40 KT LOW LEVEL JET IS PROGGED ON THE GFS/SREF/ECMWF TO DEVELOP
AHEAD OF A LOW PRESSURE SYSTEM IN EASTERN MONTANA IN ASSOCIATION
WITH A TROUGH PROPAGATING INTO THE CENTRAL ROCKIES ON SATURDAY NIGHT
AND INTO SUNDAY MORNING. HOWEVER...BEST WARM AIR ADVECTION AND
INSTABILITY SHOULD FOCUS NORTH AND EAST OF THE BIS CWA AND WILL
LEAVE OUT A MENTION OF ELEVATED THUNDERSTORMS FOR MOST OF WESTERN
AND CENTRAL NORTH DAKOTA.
WINDS WILL INCREASE ACROSS WESTERN AND CENTRAL NORTH DAKOTA ON
SUNDAY AS LOW PRESSURE CONTINUES TO DEEPEN ACROSS EASTERN MONTANA.
UNIDIRECTIONAL FLOW THROUGH 650MB WITH 30 TO 35 KTS TO MIX WILL
PROMOTE SUSTAINED SOUTH-SOUTHEASTERLY WINDS OF 15-20KTS WITH GUSTS
TO 35KTS DURING THE AFTERNOON ON SUNDAY. MODELS ARE IN AGREEMENT
WITH SLOWING THE ONSET OF PRECIPITATION TO SUNDAY EVENING AND INTO
THE OVERNIGHT IN ASSOCIATION WITH A NEGATIVELY TILTED SHORTWAVE
ENTERING WESTERN NORTH DAKOTA.
.LONG TERM...
ECMWF CONTINUES TO BE THE MODEL OF CHOICE THROUGH THE
EXTENDED...WITH THE GFS SLIGHTLY FASTER. THE OVERALL PATTERN AND
MESSAGE REMAINS THE SAME....UNSETTLED THROUGH WEDNESDAY THEN DRY
WEATHER FOR THURSDAY AND FRIDAY. HAVE BEEN WATCHING A LEADING
SHORTWAVE TROUGH MOVING THROUGH MONDAY. WILL CONTINUE WITH A CHC
WORDING FOR CENTRAL AND EASTERN SECTIONS WITH DIMINISHING POPS WEST
AND SOUTHWEST. SOUTHWEST FLOW CONTINUES AHEAD OF THE NEXT SHORTWAVE
TROUGH WHICH COMES THROUGH TUESDAY INTO WEDNESDAY. CHC OF SHOWERS
AND THUNDERSTORMS TUESDAY THROUGH TUESDAY NIGHT...THEN TAPERING TO
SLIGHT CHC ON WEDNESDAY. WEDNESDAY ALSO LOOKS TO BE THE COOLEST DAY
WITH HIGHS IN THE UPPER 60S AND LOWER 70S AS THE UPPER TROUGH SCOOTS
THROUGH. ZONAL FLOW THURSDAY AND DRY...THEN SOUTHWEST FLOW AND DRY
WEATHER FOR FRIDAY.
&&
.AVIATION...
A SURFACE TROUGH AND WEAK UPPER DISTURBANCE WILL MIGRATE
THROUGH CENTRAL AND EASTERN NORTH DAKOTA THIS AFTERNOON AND EVENING.
SOUTH TO SOUTHWEST WINDS OF 15 TO 25 MPH AHEAD OF THE TROUGH...ALONG
WITH A SLIGHT CHANCE FOR THUNDERSTORMS FOR KBIS THROUGH 03Z...AND
KJMS THROUGH 08Z. WEST TO NORTHWEST WINDS BETWEEN 10 AND 20 MPH
BEHIND THE TROUGH WITH GREATER STABILITY WILL DOMINATE THE
WEST...THUS VFR CONDITIONS AND DRY WEATHER FOR KMOT/KISN/DIK THIS
EVENING. VFR CONDITIONS EXPECTED TONIGHT THROUGH FRIDAY OVER ALL
AERODROMES.
&&
.FIRE WEATHER...
RELATIVE HUMIDTY VALUES IN THE 15 TO 20 PERCENT RANGE BEHIND A
SURFACE TROUGH AXIS FROM MINOT TO HETTINGER WILL SLOWLY RECOVER
AFTER SUNSET THIS EVENING. RELATIVE HUMIDTY VALUES WILL ONCE
AGAIN FALL INTO THE 15 TO 20 PERCENT RANGE WEST OF HIGHWAY 83 ON
FRIDAY. HOWEVER...LIGHT SURFACE WINDS AHEAD OF BUILDING HIGH
PRESSURE WILL PREVENT RED FLAG WARNING CRITERIA FROM BEING
REACHED FRIDAY. THE RANGELAND FIRE DANGER INDEX WILL BE IN THE
VERY HIGH CATEGORY WEST OF THE MISSOURI RIVER ON FRIDAY...WITH
EXTREME FIRE DANGER VALUES ACROSS SLOPE AND BOWMAN COUNTIES. WARM
TEMPERATURES AND DRY FUELS WILL CONTINUE VERY HIGH TO EXTREME FIRE
DANGER VALUES ACROSS THE WEST INTO SATURDAY WITH INCREASING WINDS
AND POSSIBLE RED FLAG CRITERIA BEING MET IN THE SOUTHWEST ON
SATURDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PJA/KS
000
FXUS63 KFGF 181956
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
256 PM CDT THU SEP 18 2008
.SHORT TERM...TONIGHT THROUGH SUNDAY
MAIN FORECAST CHALLENGES INCLUDE PRECIPITATION CHANCES TONIGHT
INTO EARLY TOMORROW AND TEMPERATURES THROUGHOUT THE FORECAST
PERIOD. GFS AND NAM IN GOOD AGREEMENT...SO USED A MODEL BLEND FOR
THIS FORECAST PACKAGE. RELIED HEAVILY ON MAV/MAV_BC GUIDANCE FOR
TEMPERATURES...WHICH HAVE PERFORMED WELL THE PAST FEW DAYS.
19 UTC SURFACE ANALYSIS SHOWS TROUGH AXIS ACROSS THE WESTERN
DAKOTAS. ACTUAL SURFACE BOUNDARY APPEARS TO BE JUST WEST OF MINOT
STRETCHING TO THE SOUTHWEST CORNER OF NORTH DAKOTA AS EVIDENT BY
DEVELOPING TOWERING CUMULUS ON VISIBLE SATELLITE IMAGERY. MODELS
ARE IN GOOD AGREEMENT SHOWING THIS FEATURE MOVING EASTWARD ACROSS
NORTH DAKOTA LATE THIS AFTERNOON AND EVENING. STILL DECENT AMOUNT
OF INSTABILITY OUT AHEAD OF THE BOUNDARY LATE THIS AFTERNOON WITH
ML CAPE VALUES 1000-1500 J/KG AND SHOWALTER VALUES NEAR -5.
HOWEVER...CAP IS STRONG. NOT EXPECTING ANY CONVECTIVE DEVELOPMENT
UNTIL MESOSCALE FORCING FROM SURFACE BOUNDARY CAN HELP BREAK
THROUGH THE CONVECTIVE INHIBITION. BEST CHANCE FOR THIS TO HAPPEN
IS ACROSS SOUTHEAST NORTH DAKOTA...AND ALONG AND EAST OF THE RED
RIVER VALLEY AFTER 00 UTC TONIGHT. INSTABILITY WEAKENS DURING THIS
TIME AND 0-6 KM SHEAR IS AROUND 30 KTS OR LESS...SO SEVERE
POTENTIAL WILL BE LIMITED. EXPECT A FEW THUNDERSTORMS AT BEST.
DRY AND SLIGHTLY COOLER WEATHER RETURNS FOR FRIDAY AS SURFACE HIGH
PRESSURE BUILDS SOUTHEASTWARD FROM CANADA...ALTHOUGH TEMPERATURES WILL
STILL BE WELL ABOVE SEASONAL NORMALS FOR MID-SEPTEMBER. SOME AREAS
ACROSS THE SOUTHERN RED RIVER VALLEY MAY ONCE AGAIN TOP 80
DEGREES. WINDS WILL BE LESS THAN TODAY...GENERALLY FROM THE WEST-
NORTHWEST.
ATTENTION THEN TURNS TO ANOTHER COLD FRONT FROM CANADA FRIDAY
NIGHT INTO EARLY SATURDAY. MOISTURE LOOKS TO BE LIMITED WITH THIS
FEATURE...SO MAIN IMPACT WILL BE DECREASING TEMPERATURES SATURDAY.
EXPECT FAIRLY STRONG THERMAL GRADIENT FROM NORTH TO SOUTH...WITH
AREAS ACROSS THE NORTH IN THE MID 60S AND AREAS TO THE SOUTH IN
THE MID 70S. TEMPERATURES FORECAST TO REBOUND SLIGHTLY ON
SUNDAY...REMAINING DRY THROUGH THE REMAINDER OF THE WEEKEND.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT THURSDAY
500 MB TROUGH WILL MOVE EAST INTO THE PACIFIC NORTHWEST OVER THE
WEEKEND WITH THE FIRST SHORT WAVE ROUNDING THE BASE OF THE TROUGH
AND MOVING INTO THE NRN PLAINS MONDAY...WITH A MORE POTENT ONE
MOVING THRU TUES-EARLY WED. 12Z MODEL RUNS HAVE SHOWN PRETTY GOOD
CONTINUITY REGARDING THIS TREND AND THUS LITTLE CHANGE NEEDED TO
EXTENDED WITH CHC POPS LATE SUNDAY INTO WEDNESDAY. PER COORDINATION
WITH NEIGHBORING OFFICES DID GO DRY ON THURSDAY AS FRONT WELL EAST
OF THE AREA DESPITE LOW CHC POPS GIVEN BY HPC GUIDANCE.
&&
.AVIATION...
THE ATMOSPHERIC COLUMN CONTINUES TO SHOW SOME MID LEVEL MOISTURE
THRU FRIDAY OVER THE AREA...THOUGH COVERAGE MOSTLY SCATTERED...WITH
BROKEN CLOUD COVER ALONG THE INTERNATIONAL BORDER. WEAK TROUGH WILL
PASS THRU DVL REGION EARLY THIS EVENING WITH WIND SHIFT TO THE
WEST. THE TROUGH WILL MOVE INTO THE RED RIVER VALLEY AND NW MN
OVERNIGHT WITH SOUTH WINDS SHIFTING SOUTHWEST OR POSSIBLE WEST FOR
A TIME LATE TONIGHT INTO FRIDAY AHEAD OF COLD FRONT DUE TO DROP
THRU THE AREA FRI AFTN/EVE. CONVECTIVE POTENTIAL THIS EVE LOOKS
WEAK AND DID NOT MENTION IN TAFS. ISOLD COVERAGE AT BEST 00Z-08Z
TIME PERIOD RED RIVER VALLEY INTO NORTHWEST MINNESOTA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
ROGERS/RIDDLE
000
FXUS63 KBIS 181546
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1046 AM CDT THU SEP 18 2008
.UPDATE...
FORECAST UPDATED TO INCLUDE ISOLATED THUNDERSTORM CHANCES ACROSS
THE SOUTHWEST AND SOUTH CENTRAL LATE THIS MORNING AND INTO THE
AFTERNOON. STRONG MID LEVEL LAPSE RATES EVIDENT ON THE 12Z KBIS
SOUNDINGS AND ALTOCU FIELDS ON VISIBLE SATELLITE IN ASSOCIATION
WITH AN INSTABILITY AXIS AHEAD OF A SURFACE TROUGH EXTENDING FROM
BUFFALO SOUTH DAKOTA THROUGH MINOT ARE ALREADY SUPPORTING A FEW
CELLS ON THE KBIS WSR-88D ACROSS SIOUX...CORSON AND PERKINS
COUNTIES. FURTHER INSOLATION WILL CONTINUE TO DESTABILIZE THE
LOWER TROPOSPHERE WITH MID 50S DEWPOINTS AND HIGH TEMPERATURES
EXPECTED TO CLIMB INTO THE MID 80S...YIELDING AOA 1000 J/KG OF
CAPE AHEAD OF THE TROUGH AXIS. 850MB WARM AIR ADVECTION WILL
PRODUCE A WEAK CAP ACROSS THE SOUTH CENTRAL AND SOUTHEAST.
HOWEVER...DO BELIEVE THAT DIURNAL HEATING SHOULD BE ENOUGH TO
OVERCOME THE MOIST-ADIABATIC THERMAL LAYER FROM 800-750MB TO ALLOW
AN INCREASE IN CONVECTIVE COVERAGE. 25 KTS OF DEEP LAYER SHEAR
SUPPORTING ANY CELLS THAT DO DEVELOP POINT TO AN ISOLATED HAIL
THREAT.
FURTHERMORE...LOWERED TEMPERATURES ACROSS THE WEST FOR TONIGHT
INTO THE UPPER 30S TO LOWER 40S WITH DRY AIR IN CENTRAL MONTANA
ADVECTING INTO WESTERN ND LATER TODAY AND CLEAR SKIES EXPECTED TO
ALLOW FOR GOOD RADIATIONAL COOLING.
&&
.SHORT TERM...
.LONG TERM...
&&
.PREV DISCUSSION... /ISSUED 300 AM CDT THU SEP 18 2008/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE SLIGHT
CONVECTIVE CHANCES LATER TODAY AND TONIGHT...THEN AGAIN LATE
SATURDAY NIGHT. OTHERWISE WILL BE WARM AND MILD TODAY AND FRIDAY
WITH A SLIGHT COOL DOWN IN STORE FOR SATURDAY. OVERALL NOT TOO MANY
DIFFERENCES IN MODEL SOLUTIONS THROUGH THE SHORT TERM. GFS HAS BEEN
MORE CONSISTENT AND WILL GET THE NOD FOR ANY DETAILS FOR DAY TWO AND
THREE.
CURRENTLY...AS ADVERTISED THE RIDGE IS BREAKING DOWN ACROSS OUR
LOCAL REGION AS THE REMNANTS OF A CLOSED UPPER LOW EJECTS
EAST-NORTHEAST ACROSS THE INTERMOUNTAIN WEST/NORTHERN ROCKIES. IN
RESPONSE A SURFACE TROUGH IS ADVANCING EAST INTO THE WESTERN
DAKOTAS...KEEPING OUR WINDS FROM THE SOUTHEAST AT AROUND 10 TO 15
MPH...AND HELPING TO TRANSPORT LOW LEVEL MOISTURE INTO THE LOCAL
AREA.
RESIDUAL S/WV ENERGY AND ITS ASSOCIATED WEAK SURFACE TROUGH WILL
MOVE ACROSS WEST AND CENTRAL ND THIS AFTERNOON AND TONIGHT.
CONTINUED MOISTURE TRANSPORT AHEAD OF THE TROUGH WILL INCREASE OUR
INSTABILITY THROUGHOUT THE DAY TO AROUND 500-1000 J/KG. HOWEVER...A
STRONG CAP IS STILL ADVERTISED TO BE IN PLACE SO WILL LEAVE MUCH OF
THE FORECAST AREA DRY. WEAKER CIN OVER MY SOUTHWEST LATER THIS
AFTERNOON SO WILL CONTINUE SLIGHT CHANCES FOR THUNDER THERE. BUFFER
SOUNDINGS CONTINUE ON THE DRY SIDE...BUT MAY BE ENOUGH MOISTURE TO
TRIGGER A FEW LATE DAY THUNDERSTORMS...AGAIN SOUTHWEST. THIS IS
SUPPORTED BY THE 4KM NMM WRF MODEL. RESIDUAL S/WV ENERGY CONTINUES
TO MOVE ACROSS THE LOCAL REGION TONIGHT...PROVIDING THE POSSIBLE
TRIGGER FOR NOCTURNAL THUNDERSTORMS SO WILL ALSO CONTINUE OUR SLIGHT
CHANCE POPS OVER THE SOUTH CLOSER TO THE SFC TROUGH AXIS. SPC HAS
ALSO JUMPED ON THIS PUTTING THIS AREA IN THE GENERAL OUTLOOK FOR DAY
ONE.
TEMPERATURES WILL WARM INTO THE 80S ACROSS WESTERN AND CENTRAL NORTH
DAKOTA TODAY...WITH A FEW LOWER 90S NOT OUT OF THE QUESTION. MUCH
LIGHTER WINDS EXPECTED ACROSS THE WEST ALONG AND BEHIND THE SURFACE
TROUGH WHICH WILL HELP TO GREATLY REDUCE FIRE WEATHER CONCERNS
THERE. STILL BREEZY AHEAD OF THE TROUGH ACROSS MY SOUTH CENTRAL AND
EASTERN COUNTIES.
ON FRIDAY ANOTHER SURFACE COLD FRONT APPROACHES FROM THE NORTH AND
PUSHES INTO THE STATE IN RESPONSE TO A SIGNIFICANT UPPER WAVE
ADVANCING EAST ACROSS CENTRAL CANADA. DAYTIME HIGHS ON FRIDAY
HOWEVER DONT COOL DOWN ALL THAT MUCH AS THE FROPA TIMING TAKES PLACE
IN THE AFTERNOON AND MORE SO NORTH. THE MAIN AFFECTS OF THE COLD
FRONT ARE NOT FELT UNTIL SATURDAY AFTER THE BEST CAA TAKES PLACE
FRIDAY NIGHT. CONTINUED THE TREND OF LOWERING TEMPERATURES A FEW
DEGREES ON SATURDAY BUT STILL ABOVE NORMAL FOR THIS TIME OF YEAR.
ALSO ON SATURDAY...RETURN FLOW INITIATES OVER THE CWA AHEAD OF THE
NEXT SURFACE AND UPPER TROUGHS (THIS UPPER TROUGH IS OF THE
SIGNIFICANT VARIETY). AS THE UPPER TROUGH ADVANCES INTO THE NORTHERN
ROCKIES SATURDAY NIGHT...OUR FLOW ALOFT TRANSITIONS TO SOUTHWEST.
WILL THROW IN SOME OVERNIGHT POPS ACROSS THE FAR WEST FOR THIS
PATTERN CHANGE.
LONG TERM...SUNDAY THROUGH THURSDAY NIGHT...
MODELS REMAIN IN FIAR AGREEMENT PUSHING CENTRAL CONUS RIDGING EAST
AS TROUGH MOVES ONSHORE TO PACIFIC NORTH WEST EARLY IN EXTENDED
PERIODS. A COOLER AND WETTER REGIME WILL FOLLOW THROUGH REMAINDER OF
EXTENDED PERIODS AS TROUGH MOVES ONLY SLOWLY EAST AND SETTLES JUST
TO EAST OF FORECAST AREA AT END OF FORECAST. TEMPERATURES 10 DEGREES
COOLER WITH A CHANCE TO SLIGHT CHANCE OF POPS THROUGH MOST OF NEXT
WORK WEEK.
AVIATION...
BIGGEST AVIATION CONCER WILL BE SLIGHT CHANCE CONVECTION THIS
AFTERNOON AND EVENING AND WILL COVER WITH VICINITY SHOWER OR
OCCASIONAL PROB 30 IN EASTERN PORTION OF FORECAST AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PJA
000
FXUS63 KFGF 181530
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1030 AM CDT THU SEP 18 2008
.DISCUSSION...
14 UTC SURFACE ANALYSIS SHOWS WEAK SURFACE TROUGH ACROSS THE
WESTERN DAKOTAS AND EASTERN MONTANA/WYOMING. BOTH GFS/NAM SHOW
THIS FEATURE MOVING SLOWLY EASTWARD TODAY AND ACROSS THE RED RIVER
VALLEY BY MIDNIGHT TONIGHT. ML CAPE PROGGED TO BE 1000-1500 J/KG THIS
AFTERNOON ALONG AND AHEAD OF SURFACE TROUGH WITH SHOWALTER VALUES
FROM -3 TO -4. HOWEVER...SIGNIFICANT CONVECTIVE INHIBITION IN
PLACE THROUGH THE DAY WITH 850 TO 700 HPA THERMAL RIDGE ACROSS
CENTRAL AND EASTERN NORTH DAKOTA. WARMER TEMPERATURES ALOFT SHOULD
SUPPRESS CONVECTION UNTIL AFTER 00 UTC ONCE CAP BEGINS TO BREAK
DOWN NEAR SURFACE BOUNDARY. EVEN THEN...ONLY EXPECT A FEW NON-
SEVERE THUNDERSTORMS TO DEVELOP AT MOST.
MAIN STORY FOR THIS AFTERNOON WILL BE WARMER TEMPERATURES AND BREEZY
CONDITIONS. WITH TEMPERATURES FROM THE SURFACE TO 700 HPA 3 TO 6 C
WARMER THAN YESTERDAY PER 12 UTC BISMARCK SOUNDING AND SUFFICIENT
BOUNDARY LAYER MIXING WITH THERMAL RIDGE ALOFT...EXPECT MAXIMUM
TEMPERATURES TODAY TO BE UP TO 10 DEGREES WARMER THAN YESTERDAY.
SOME SPOTS MAY SEE 80 DEGREES. GFS/NAM SHOW SOUTHERLY 925 HPA WINDS
THIS AFTERNOON FROM 25 TO 30 KTS. AS SUCH...SURFACE WINDS WILL PICK
UP THIS AFTERNOON...SUSTAINED 15 TO 25 MPH WITH OCCASIONAL GUSTS
TO 35 MPH.
CURRENT GRIDS IN GOOD SHAPE WITH NO MAJOR UPDATES REQUIRED. LET
SLIGHT CHANCE POPS DROP AFTER 16 UTC ACROSS FAR NORTHEAST ZONES
WITH CURRENT RADAR TRENDS SHOWING REMAINING SHOWER ACTIVITY ACROSS
SOUTHERN CANADA...MOVING EAST-NORTHEASTWARD.
&&
.AVIATION...
MID AND HIGH LEVEL MOISTURE WILL CONTINUE OVER NE ND THRU NW MN.
THE THREAT FOR ANY THUNDERSTORMS HAS SHIFTED INTO ONTARIO.
SOUTHERLY WINDS WILL INCREASE TO 15 TO 25 KTS TODAY WITH GUSTS TO
30-35 KTS LIKELY...ESPECIALLY IN THE RED RIVER VALLEY DURING THE
AFTN. WINDS JUST OFF THE SURFACE TO 2000 FT AGL WILL BE FROM THE
SOUTH NEAR 35 KTS.
&&
.PREV DISCUSSION... /ISSUED 230 AM CDT THU SEP 18 2008/
DISCUSSION...FORECAST CHALLENGE CONCERNS TEMPERATURES AND PCPN
CHANCES. MODELS CONTINUE IN PRETTY CLOSE AGREEMENT THROUGH PERIOD.
GFS PICKING UP ON CURRENT PCPN WELL SO WILL LIKELY USE IT FOR
DETAILS.
IN THE NEAR TERM WILL MONITOR RIBBON OF SHRA OVER NE FA FOR AM
MENTION. THIS ASSOCIATED WITH LEADING EDGE OF WARM ADVECTION AND
850MB CONVERGENCE ZONE. CONVERGENCE WEAKENS AFT 06Z AND WEAKENING
TREND HAS BEEN NOTED. WILL LIKELY BE ABLE TO PULL MORNING POPS OVER
FAR NE BASED ON CURRENT TRENDS. FOR REMAINDER OF DAY MID LEVELS
BRIEFLY DRY FOR LOTS OF SOLAR AND WITH THERMAL RIDGE AXIS NOSING
INTO FA WILL BE A WARM DAY WITH WELL ABOVE AVERAGE TEMPERATURES.
MID LEVEL SHORT WAVE AND ASSOCIATED PREFRONTAL SURFACE TROUGH
PROPAGATES EAST INTO FA TONIGHT. MODEST INSTABILITY AND CAPE
EXPECTED BY EVENING BUT INITIALLY THERE WILL BE A SIZABLE AMOUNT OF
CONVECTIVE INHIBITION TO OVERCOME. CIN IS MINIMIZED BY 06Z BUT
NEITHER 0-6KM SHEAR OR CONVERGENCE WITH LOW LEVEL JET IMPRESSIVE SO
WILL LEAVE POPS IN SLIGHT CHANCE RANGE.
COLD FRONT DROPS THROUGH FRIDAY AFTERNOON AFFECTING MAINLY FAR
NORTHERN PORTIONS OF FA. THERMAL RIDGE REMAINS OVER THE SOUTH SO
WILL LIKELY BE A RESPECTABLE THERMAL GRADIENT FROM N-S. OVERALL
THOUGH TEMPERATURES EVEN ACROSS THE NORTH WILL BE WARM FOR THIS TIME
OF YEAR. COLUMN UNDERGOES DRYING BLO 500MB SO NOT ANTICIPATING ANY
PCPN CHANCES THROUGH SATURDAY.
COOLING INTO SATURDAY LOOKS MORE AGGRESSIVE THAN IN PREVIOUS MODEL
RUNS. WILL NEED TO TRIM TEMPERATURES SOMEWHAT AS A START. IF TRENDS
CONTINUE MAY NEED TO TRIM MAX TEMPERATURES MORE DEPENDING ON
POTENTIAL CLOUD COVER.
TEMPERATURES RECOVER SOMEWHAT SUNDAY AS RETURN FLOW INCREASE AND MID
LEVEL SHORT WAVE RIDGE CROSSES FA.
WILL MAINTAIN POPS OVER LONGER RANGE AS REGION TRANSITIONS TO SW
FLOW ALOFT WITH SERIES OF SHORT WAVES LIFTING NE THROUGH FA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
ROGERS/RIDDLE/VOELKER
000
FXUS63 KBIS 180801
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
300 AM CDT THU SEP 18 2008
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT...
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE SLIGHT
CONVECTIVE CHANCES LATER TODAY AND TONIGHT...THEN AGAIN LATE
SATURDAY NIGHT. OTHERWISE WILL BE WARM AND MILD TODAY AND FRIDAY
WITH A SLIGHT COOL DOWN IN STORE FOR SATURDAY. OVERALL NOT TOO MANY
DIFFERENCES IN MODEL SOLUTIONS THROUGH THE SHORT TERM. GFS HAS BEEN
MORE CONSISTENT AND WILL GET THE NOD FOR ANY DETAILS FOR DAY TWO AND
THREE.
CURRENTLY...AS ADVERTISED THE RIDGE IS BREAKING DOWN ACROSS OUR
LOCAL REGION AS THE REMNANTS OF A CLOSED UPPER LOW EJECTS
EAST-NORTHEAST ACROSS THE INTERMOUNTAIN WEST/NORTHERN ROCKIES. IN
RESPONSE A SURFACE TROUGH IS ADVANCING EAST INTO THE WESTERN
DAKOTAS...KEEPING OUR WINDS FROM THE SOUTHEAST AT AROUND 10 TO 15
MPH...AND HELPING TO TRANSPORT LOW LEVEL MOISTURE INTO THE LOCAL
AREA.
RESIDUAL S/WV ENERGY AND ITS ASSOCIATED WEAK SURFACE TROUGH WILL
MOVE ACROSS WEST AND CENTRAL ND THIS AFTERNOON AND TONIGHT.
CONTINUED MOISTURE TRANSPORT AHEAD OF THE TROUGH WILL INCREASE OUR
INSTABILITY THROUGHOUT THE DAY TO AROUND 500-1000 J/KG. HOWEVER...A
STRONG CAP IS STILL ADVERTISED TO BE IN PLACE SO WILL LEAVE MUCH OF
THE FORECAST AREA DRY. WEAKER CIN OVER MY SOUTHWEST LATER THIS
AFTERNOON SO WILL CONTINUE SLIGHT CHANCES FOR THUNDER THERE. BUFFER
SOUNDINGS CONTINUE ON THE DRY SIDE...BUT MAY BE ENOUGH MOISTURE TO
TRIGGER A FEW LATE DAY THUNDERSTORMS...AGAIN SOUTHWEST. THIS IS
SUPPORTED BY THE 4KM NMM WRF MODEL. RESIDUAL S/WV ENERGY CONTINUES
TO MOVE ACROSS THE LOCAL REGION TONIGHT...PROVIDING THE POSSIBLE
TRIGGER FOR NOCTURNAL THUNDERSTORMS SO WILL ALSO CONTINUE OUR SLIGHT
CHANCE POPS OVER THE SOUTH CLOSER TO THE SFC TROUGH AXIS. SPC HAS
ALSO JUMPED ON THIS PUTTING THIS AREA IN THE GENERAL OUTLOOK FOR DAY
ONE.
TEMPERATURES WILL WARM INTO THE 80S ACROSS WESTERN AND CENTRAL NORTH
DAKOTA TODAY...WITH A FEW LOWER 90S NOT OUT OF THE QUESTION. MUCH
LIGHTER WINDS EXPECTED ACROSS THE WEST ALONG AND BEHIND THE SURFACE
TROUGH WHICH WILL HELP TO GREATLY REDUCE FIRE WEATHER CONCERNS
THERE. STILL BREEZY AHEAD OF THE TROUGH ACROSS MY SOUTH CENTRAL AND
EASTERN COUNTIES.
ON FRIDAY ANOTHER SURFACE COLD FRONT APPROACHES FROM THE NORTH AND
PUSHES INTO THE STATE IN RESPONSE TO A SIGNIFICANT UPPER WAVE
ADVANCING EAST ACROSS CENTRAL CANADA. DAYTIME HIGHS ON FRIDAY
HOWEVER DONT COOL DOWN ALL THAT MUCH AS THE FROPA TIMING TAKES PLACE
IN THE AFTERNOON AND MORE SO NORTH. THE MAIN AFFECTS OF THE COLD
FRONT ARE NOT FELT UNTIL SATURDAY AFTER THE BEST CAA TAKES PLACE
FRIDAY NIGHT. CONTINUED THE TREND OF LOWERING TEMPERATURES A FEW
DEGREES ON SATURDAY BUT STILL ABOVE NORMAL FOR THIS TIME OF YEAR.
ALSO ON SATURDAY...RETURN FLOW INITIATES OVER THE CWA AHEAD OF THE
NEXT SURFACE AND UPPER TROUGHS (THIS UPPER TROUGH IS OF THE
SIGNIFICANT VARIETY). AS THE UPPER TROUGH ADVANCES INTO THE NORTHERN
ROCKIES SATURDAY NIGHT...OUR FLOW ALOFT TRANSITIONS TO SOUTHWEST.
WILL THROW IN SOME OVERNIGHT POPS ACROSS THE FAR WEST FOR THIS
PATTERN CHANGE.
.LONG TERM...SUNDAY THROUGH THURSDAY NIGHT...
MODELS REMAIN IN FIAR AGREEMENT PUSHING CENTRAL CONUS RIDGING EAST
AS TROUGH MOVES ONSHORE TO PACIFIC NORTH WEST EARLY IN EXTENDED
PERIODS. A COOLER AND WETTER REGIME WILL FOLLOW THROUGH REMAINDER OF
EXTENDED PERIODS AS TROUGH MOVES ONLY SLOWLY EAST AND SETTLES JUST
TO EAST OF FORECAST AREA AT END OF FORECAST. TEMPERATURES 10 DEGREES
COOLER WITH A CHANCE TO SLIGHT CHANCE OF POPS THROUGH MOST OF NEXT
WORK WEEK.
&&
.AVIATION...
BIGGEST AVIATION CONCER WILL BE SLIGHT CHANCE CONVECTION THIS
AFTERNOON AND EVENING AND WILL COVER WITH VICINITY SHOWER OR
OCCASIONAL PROB 30 IN EASTERN PORTION OF FORECAST AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
NH/HW
000
FXUS63 KFGF 180731
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
230 AM CDT THU SEP 18 2008
.DISCUSSION...FORECAST CHALLENGE CONCERNS TEMPERATURES AND PCPN
CHANCES. MODELS CONTINUE IN PRETTY CLOSE AGREEMENT THROUGH PERIOD.
GFS PICKING UP ON CURRENT PCPN WELL SO WILL LIKELY USE IT FOR
DETAILS.
IN THE NEAR TERM WILL MONITOR RIBBON OF SHRA OVER NE FA FOR AM
MENTION. THIS ASSOCIATED WITH LEADING EDGE OF WARM ADVECTION AND
850MB CONVERGENCE ZONE. CONVERGENCE WEAKENS AFT 06Z AND WEAKENING
TREND HAS BEEN NOTED. WILL LIKELY BE ABLE TO PULL MORNING POPS OVER
FAR NE BASED ON CURRENT TRENDS. FOR REMAINDER OF DAY MID LEVELS
BRIEFLY DRY FOR LOTS OF SOLAR AND WITH THERMAL RIDGE AXIS NOSING
INTO FA WILL BE A WARM DAY WITH WELL ABOVE AVERAGE TEMPERATURES.
MID LEVEL SHORT WAVE AND ASSOCIATED PREFRONTAL SURFACE TROUGH
PROPAGATES EAST INTO FA TONIGHT. MODEST INSTABILITY AND CAPE
EXPECTED BY EVENING BUT INITIALLY THERE WILL BE A SIZABLE AMOUNT OF
CONVECTIVE INHIBITION TO OVERCOME. CIN IS MINIMIZED BY 06Z BUT
NEITHER 0-6KM SHEAR OR CONVERGENCE WITH LOW LEVEL JET IMPRESSIVE SO
WILL LEAVE POPS IN SLIGHT CHANCE RANGE.
COLD FRONT DROPS THROUGH FRIDAY AFTERNOON AFFECTING MAINLY FAR
NORTHERN PORTIONS OF FA. THERMAL RIDGE REMAINS OVER THE SOUTH SO
WILL LIKELY BE A RESPECTABLE THERMAL GRADIENT FROM N-S. OVERALL
THOUGH TEMPERATURES EVEN ACROSS THE NORTH WILL BE WARM FOR THIS TIME
OF YEAR. COLUMN UNDERGOES DRYING BLO 500MB SO NOT ANTICIPATING ANY
PCPN CHANCES THROUGH SATURDAY.
COOLING INTO SATURDAY LOOKS MORE AGGRESSIVE THAN IN PREVIOUS MODEL
RUNS. WILL NEED TO TRIM TEMPERATURES SOMEWHAT AS A START. IF TRENDS
CONTINUE MAY NEED TO TRIM MAX TEMPERATURES MORE DEPENDING ON
POTENTIAL CLOUD COVER.
TEMPERATURES RECOVER SOMEWHAT SUNDAY AS RETURN FLOW INCREASE AND MID
LEVEL SHORT WAVE RIDGE CROSSES FA.
WILL MAINTAIN POPS OVER LONGER RANGE AS REGION TRANSITIONS TO SW
FLOW ALOFT WITH SERIES OF SHORT WAVES LIFTING NE THROUGH FA.
&&
.AVIATION...MAY SEE SOME HIGH VFR CIGS OVER NE FA EARLY THIS AM
OTHERWISE NO CIGS EXPECTED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER
| 
