[top]
000
FXUS63 KLOT 082144
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
344 PM CST SAT NOV 8 2008
.DISCUSSION...
342 PM CST
A LARGE UPPER AIR TROUGH WILL MOVE ACROSS THE GREAT LAKES TONIGHT
THROUGH MONDAY NIGHT. THIS TROUGH WILL AFFECT THE WEATHER ACROSS
THE REGION OF NORTH CENTRAL ILLINOIS...NORTHEAST ILLINOIS AND
NORTHWEST INDIANA.
TONIGHT... THE CLOUDS WILL REMAIN OVER THE REGION OVERNIGHT. THE
SATELLITE VISIBLE AND IR IMAGERY SHOWS CLOUDS WILL INTO
MINNESOTA...IOWA AND THE DAKOTAS. THIS TROUGH IS SLOW MOVING. THE
FORECAST SOUNDINGS FROM GFS AND OUR LOCAL WRF ADVANCED RESEARCH
WEATHER MODEL SHOW A DEWPOINT SPREAD OF LESS THAN 5 DEGREES AROUND
3400 FEET SUNDAY. THIS INDICATES SOME CLOUDS WILL BE IN THE REGION
AS LATE AS SUNDAY AFTERNOON. WE EXPECT STRATOCUMULUS CLOUDS
TONIGHT AND SUNDAY...SO WE WILL FORECAST A MOSTLY CLOUDY TO CLOUDY
SKY. THE REST OF THE ATMOSPHERE ABOVE 3400 FEET WILL BECOME
DRIER...SO THERE MAY BE BREAKS IN THE CLOUDS SUNDAY AFTERNOON. THE
TEMPERATURE WILL FALL TONIGHT. SURFACE OBSERVATIONS AT 16 UTC
COMPARED TO SURFACE OBSERVATIONS AT 20 UTC SHOW THE TEMPERATURE
AND DEWPOINT WERE NEARLY STEADY WITH SOME SLIGHT RISE FROM THE
SOLAR RADIATION THAT CAME TROUGH THE CLOUDS TODAY. THE WIND SHIFT
TO THE NORTHWEST IS EXPECTED LATER TONIGHT AS THE SURFACE LOW OVER
SOUTHERN ONTARIO MOVES NORTHEAST. COLDER AIR IN MINNESOTA AND
IOWA WILL MOVE INTO THE REGION LATER TONIGHT. WE WILL FORECAST LOW
TEMPERATURES IN THE UPPER 20S AND LOWER 30S TONIGHT AND MIDDLE TO
UPPER 20S SUNDAY NIGHT. WE USED A CORRECTED TEMPERATURE FORECAST
BASED ON ERRORS ON THE GFS MOS GUIDANCE FROM THE LAST SEVEN DAYS.
THIS WAS AN ADDITIONAL CORRECTION TO THE MOS FORECASTS WE APPLIED
THROUGH FORECAST DAY 3.
SUNDAY...THE SOLAR HEATING DURING THE DAY AND FORECAST COLD TEMPERATURES
IN THE 850 MB TO 500 MB LEVEL WILL PRODUCE SOME SCATTERED SNOW
SHOWERS. THESE SNOW SHOWERS ARE FORECAST TO BE VERY LIGHT ACROSS
THE REGION.
MONDAY THROUGH THURSDAY... THE LARGE TROUGH WILL MOVE EAST TO QUEBEC
AND NORTHEAST UNITED STATES BY MONDAY NIGHT. THE GFS MODEL AND
ECMWF MODEL WERE PRODUCING PRECIPITATION FOR SOUTH OF INTERSTATE
80 FOR MONDAY NIGHT. THE PRECIPITATION IS FORECAST TO MOVE NORTH
INTO MOST OF THE REGION DURING TUESDAY. WE WILL FORECAST RAIN
MIXED WITH SNOW MONDAY NIGHT. AS THE TEMPERATURES INCREASE TUESDAY
THROUGH WEDNESDAY...WE WILL FORECAST RAIN. GFS MODEL FORECAST OF
ISENTROPIC SURFACES AT 295 DEGREES KELVIN AND 300 DEGREES
KELVIN...SHOW LIFT OR UPWARD VERTICAL MOTION STARTING MONDAY NIGHT
AND CONTINUING THROUGH THURSDAY. THE MAXIMUM LIFT IS FORECAST
TUESDAY AND WEDNESDAY AND THEN IT DECREASES A LITTLE ON THURSDAY.
WE WILL STOP THE PRECIPITATION ON THURSDAY DUE TO THE WEAK LIFT.
THEN ANOTHER UPPER LEVEL TROUGH MOVES INTO THE WESTERN GREAT LAKES
ON FRIDAY. THIS WILL BRING MORE UPWARD VERTICAL MOTION WHICH WILL
PRODUCE RAIN IN OUR REGION ON FRIDAY. WE WILL BE FORECASTING HIGH
TEMPERATURES IN THE UPPER 40S TO LOWER 50S THURSDAY AND FRIDAY.
&&
.AVIATION...
1222 PM CDT
1800 UTC TAFS...BROAD CIRCULATION OF LOW PRESSURE WILL CONTINUE TO
BE THE MAIN INFLUENCE OVER THE REGIONS WEATHER THROUGHOUT THE TAF
PERIOD. THE BEST CHANCES FOR ANY PRECIP WILL BE LATE THIS MORNING
THROUGH THE VERY EARLY AFTERNOON AS A SFC AND LOW LEVEL TROF
SWINGS THROUGH THE REGION. THERE STILL WILL REMAIN AN OUTSIDE
CHANCE OF SNOW FLURRIES INTO THE EVENING...BUT AREAL COVERAGE AND
IMPACT WILL BE MINIMAL SO WILL NOT MENTION IN THE TAFS. CEILINGS
WILL BE THE MAIN HINDRANCE WITH MVFR CIGS EXTENDING ALL THE WAY
BACK INTO NEBRASKA. CURRENTLY EXPECT THESE MVFR CIGS OF
1500-2500KFT TO PERSIST THROUGH THE REST OF THE FORECAST PERIOD AS
A LOW LEVEL INVERSION TRAPS ENOUGH MOISTURE IN THE LOW LEVELS OF
THE ATMOSPHERE. THERE ARE A FEW IFR REPORTS OFF TO THE NORTH AND
WEST...BUT THINK THAT THIS WILL STAY OUT OF OUR TAF REGION. WINDS
WILL GRADUALLY VEER FROM THE SOUTHWEST TO THE WEST THIS AFTERNOON
AND THEN TO THE NORTHWEST OVERNIGHT WITH THE GUSTS PERSISTING
THROUGHOUT.
EXPECT MVFR CONDITIONS THROUGHOUT THE TAF PERIOD.
HALBACH
&&
.MARINE...
204 PM CST
CONDITIONS ARE EXPECTED TO REMAIN ON THE GUSTY SIDE ACROSS THE
LAKE THE REST OF TODAY INTO SUNDAY. WINDS HAVE BEEN GUSTING UP TO
GALE FORCE AT TIMES ON THE SOUTHERN HALF OF THE LAKE TODAY AND
THESE GUSTS ARE EXPECTED TO CONTINUE THROUGH TONIGHT AS THE BROAD
AREA OF LOW PRESSURE LIFTS UP INTO CANADA. WINDS WILL LIKELY
REMAIN GUSTY UP UNTIL MONDAY WHEN A RIDGE OF HIGH PRESSURE PUSHES
INTO THE REGION AND BRINGS THE WINDS BACK DOWN. AFTER A BRIEF
BREAK...WINDS ARE EXPECTED TO START INCREASING AGAIN ON FRIDAY AS
A LOW PRESSURE SYSTEM TRACKS THROUGH SOUTHERN CANADA.
HALBACH
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL MIDNIGHT SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 5 AM MONDAY.
&&
$$
[top]
000
FXUS63 KILX 082101
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
301 PM CST SAT NOV 8 2008
.DISCUSSION...
ISSUED 301 PM CST SAT NOV 8 2008
MAIN CONCERN THIS PACKAGE WILL BE TIMING OF PCPN NEXT WEEK AND
RESULTING POPS IN THE SHORT TERM. IN THE LONG TERM...CONCERN WILL
BE ENDING OF PCPN AND DEGREE OF WARMING TEMPS LATE IN THE WEEK.
SHORT TERM MODELS LOOK FAIRLY GOOD BAD VERIFY WELL THROUGH 84HRS.
BOTH GFS AND NAM-WRF...AND EVEN THE ECMWF HAVE SLOWED ONSET OF
PCPN INTO THE AREA. SO GOOD MODEL AGREEMENT IN THIS FORECAST
PACKAGE. IN THE LONG TERM...THE MODELS CONTINUE TO DIFFER SOME
WITH RESULTING WEATHER AFTER THIS NEXT SYSTEM MOVES THROUGH BUT
WILL CONTINUE WITH CURRENT FORECAST CONTINUITY.
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
SYSTEM THAT HAS GIVEN US CLOUDS AND LIGHT PCPN WILL CONTINUE TO
MOVE MOVE NORTHEAST ALLOWING FOR A RIDGE OF HI PRSS TO BUILD INTO
THE REGION TOMORROW AND INTO MONDAY. CLOUDY SKIES WILL PREVAIL
TOMORROW AS THE AREA REMAINS IN CYCLONIC FLOW...BUT CLOUDS WILL
BEGIN TO PUSH OFF TO NORTHEAST TOMORROW EVENING AND OVERNIGHT.
RIDGING THEN MOVES IN FOR MONDAY WITH CONTINUED DRY WEATHER.
HOWEVER...BY MONDAY EVENING A DEVELOPING SYSTEM IN THE SOUTHERN
PLAINS WILL HAVE AN INVERTED TROUGH EXTENDING INTO MO/IOWA MONDAY
NIGHT. THIS WILL BRING THE CHANCE OF PCPN INTO THE SOUTHWESTERN
AREAS OF THE CWA EARLY MONDAY EVENING AND THEN IT WILL SPREAD
NORTH AND EAST ACROSS THE REST OF THE AREA MONDAY NIGHT.
THE INVERTED TROUGH WILL GET CLOSER TO THE AREA TUESDAY AND THIS
WILL BRING INCREASED CHANCES OF PCPN TO THE AREA DURING THE DAY.
WITH TEMPS REMAINING COLDER MONDAY NIGHT AND TUE NIGHT...PCPN TYPE
IN THE NORTHERN AREAS COULD BE MIXED RAIN AND SNOW...SO HAVE
INCLUDED THIS IN GRIDS ACCORDINGLY.
TEMPS WILL REMAIN BELOW NORMAL AND HAVE TAKEN A BLEND OF GUIDANCE.
LONG TERM...WEDNESDAY THROUGH SATURDAY
INVERTED TROUGH WILL SLOWLY MOVE EAST ACROSS THE SOUTHERN US AND
PCPN CHANCES WILL CONTINUE INTO WED. BY WED NIGHT THE PCPN SHOULD
HAVE MOVED EAST AND SOUTHEAST OF THE REGION. REMAINDER OF EXTENDED
WILL BE DRY AS A TROUGH PUSHES EAST OF THE AREA AND BEING ANOTHER
LARGE SFC HIGH PRSS AREA INTO THE STATE.
THIS LARGE AREA OF HIGH PRSS WILL ALLOW TEMPS TO WARM BACK UP INTO
THE NORMAL OR JUST ABOVE NORMAL CATEGORY.
AUTEN
&&
.AVIATION...
ISSUED 1146 AM CST SAT NOV 8 2008
MVFR CONDITIONS TO CONTINUE THROUGH THE AFTERNOON AND OVERNIGHT
HOURS WITH CIGS BELOW 2KFT IN NRN TERMINALS...AND AROUND 2500FT IN
KDEC. WINDS STAYING GUSTY THROUGH THE DAY AS THE LOW MOVES THROUGH
THE GREAT LAKES. BIG CONCERN WILL BE THE TIMING OF THE RETURN TO
VFR CONDITIONS TOMORROW MORNING. MODELS ARE SPLIT BTWN STAYING OVC
LOW... AND BREAKING IT UP AROUND SUNRISE. HAVE SPLIT THE
DIFFERENCE FOR THE FORECAST IN AN ATTEMPT TO SHOW THE TREND FOR
THE MORNING...THOUGH MAY BE A BIT TOO OPTIMISTIC.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 082005
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
205 PM CST SAT NOV 8 2008
.DISCUSSION...
249 AM CST
FOCUS WILL REMAIN ON THE MAJOR VORTEX EJECTING NORTHEAST ACROSS SRN
WISCONSIN AND ACROSS CENTRAL LAKE MICH THIS MRNG. MODELS IN STRONG
AGREEMENT THRU FIRST 48 HOURS AT LEAST ON EJECTING UPR LOW FROM LAKE
MICH ACROSS NRN LWR MICHIGAN TODAY INTO EASTERN ONTARIO BY SUNDAY
MRNG. A SECOND UPR VORTEX DEVELOPS IN WESTERN ONTARIO THIS MORNING
AND DOES A FUJIWARA SPIN DOWN OVER THE LAKES ON SUNDAY...SENDING
ANOTHER IMPULSE OF WRAPAROUND COLD CANADIAN AIR INTO NRN IL DURING
THE DAY. WHILE KEEPING CLOUD COVER AND PSBLY SOME MRNG FLURRIES
AROUND ON SUNDAY...THE GRADUAL DEPARTURE TO THE NORTHEAST WILL
DIMINISH SNOW SHOWER FREQUENCY OVER THE NEXT 36 HOURS.
WITH THIS UPR SYSTEM KICKING OUT INTO WRN QUEBEC SUNDAY NIGHT...
SKIES ARE LIKELY TO CLEAR OVERNIGHT. THE ABSENCE OF OUR BLANKET OF
CLOUD COVER WILL ALLOW HEAT TO RADIATE QUICKER...RESULTING IN SOME
OF THE COLDEST OVERNIGHT TEMPERATURES SO FAR THIS FALL.
THE DRY PERIOD ON MONDAY WILL SEE SUNSHINE DIMINISH IN THE AFTERNOON
AS WAA CLOUDINESS ADVANCES NORTHWARD FROM A DEVELOPING SYSTEM IN THE
SRN PLAINS. MODELS HANDLE THIS AGREEABLY THRU 72 HOURS BUT START
DIVERGING AFTER THAT. WITH SFC HIGH PRESSURE ENTRENCHED OVER THE
DAKOTAS AND UPR MS VLY AND CONTINUING TO PUMP COLD AIR INTO THE
GREAT LAKES REGION MONDAY AND TUESDAY...A RATHER BROAD UPR TROF OVER
THE PLAINS AND MID TO LWR MS VLY IS SUCCEEDING IN PUMPING GULF MSTR
UP THE MS VLY AND INTO PARTS OF NRN IL AND INDIANA LATE MON NGT AND
TUESDAY. IF THIS IS THE CASE WITH WARM GULF MSTR OVERRIDING FREEZING
OR NEAR FREEZING TEMPS AT THE SFC...THERE ARISES THE LIKELIHOOD OF
MIXED PCPN TUES THRU WED. THIS CUD BE EITHER RAIN OR SNOW OR BOTH OR
MINGLED WITH SLEET AND PERHAPS SOME FREEZING RAIN.
THE ECMWF IS QUITE A BIT SLOWER THAN THE GFS AND NAM IN SHIFTING UPR
RIDGING EAST OF IL AND COMING UNDER THE OVERRUNNING GULF MSTR
SCENARIO. IT ALSO EXTENDS ITS AMPLITUDE SWD OVER THE SRN PLAINS FROM
A SEPARATE UPR VORTEX LOCATED OVER THE NRN CANADIAN TERRITORIES VS
QUEBEC AS WITH NAM AND GFS. WHILE IMPRESSED WITH THE CLOSE KNIT
ALIGNMENT OF THE GFS WITH THE NAM...PAST MODEL TRENDS HAVE BEEN
EVENTUALLY SIDING WITH OR RESOLVING TOWARD THE ECMWF. BUT FOR
NOW... A GFS/NAM SOLUTION IS PRESENTLY IN EFFECT FOR THE EXTENDED
FORECAST AND WILL REMAIN SO FAR.
RLB
&&
.AVIATION...
1222 PM CDT
1800 UTC TAFS...BROAD CIRCULATION OF LOW PRESSURE WILL CONTINUE TO
BE THE MAIN INFLUENCE OVER THE REGIONS WEATHER THROUGHOUT THE TAF
PERIOD. THE BEST CHANCES FOR ANY PRECIP WILL BE LATE THIS MORNING
THROUGH THE VERY EARLY AFTERNOON AS A SFC AND LOW LEVEL TROF
SWINGS THROUGH THE REGION. THERE STILL WILL REMAIN AN OUTSIDE
CHANCE OF SNOW FLURRIES INTO THE EVENING...BUT AREAL COVERAGE AND
IMPACT WILL BE MINIMAL SO WILL NOT MENTION IN THE TAFS. CEILINGS
WILL BE THE MAIN HINDRANCE WITH MVFR CIGS EXTENDING ALL THE WAY
BACK INTO NEBRASKA. CURRENTLY EXPECT THESE MVFR CIGS OF
1500-2500KFT TO PERSIST THROUGH THE REST OF THE FORECAST PERIOD AS
A LOW LEVEL INVERSION TRAPS ENOUGH MOISTURE IN THE LOW LEVELS OF
THE ATMOSPHERE. THERE ARE A FEW IFR REPORTS OFF TO THE NORTH AND
WEST...BUT THINK THAT THIS WILL STAY OUT OF OUR TAF REGION. WINDS
WILL GRADUALLY VEER FROM THE SOUTHWEST TO THE WEST THIS AFTERNOON
AND THEN TO THE NORTHWEST OVERNIGHT WITH THE GUSTS PERSISTING
THROUGHOUT.
EXPECT MVFR CONDITIONS THROUGHOUT THE TAF PERIOD.
HALBACH
&&
.MARINE...
204 PM CST
CONDITIONS ARE EXPECTED TO REMAIN ON THE GUSTY SIDE ACROSS THE
LAKE THE REST OF TODAY INTO SUNDAY. WINDS HAVE BEEN GUSTING UP TO
GALE FORCE AT TIMES ON THE SOUTHERN HALF OF THE LAKE TODAY AND
THESE GUSTS ARE EXPECTED TO CONTINUE THROUGH TONIGHT AS THE BROAD
AREA OF LOW PRESSURE LIFTS UP INTO CANADA. WINDS WILL LIKELY
REMAIN GUSTY UP UNTIL MONDAY WHEN A RIDGE OF HIGH PRESSURE PUSHES
INTO THE REGION AND BRINGS THE WINDS BACK DOWN. AFTER A BRIEF
BREAK...WINDS ARE EXPECTED TO START INCREASING AGAIN ON FRIDAY AS
A LOW PRESSURE SYSTEM TRACKS THROUGH SOUTHERN CANADA.
HALBACH
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL MIDNIGHT SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 5 AM MONDAY.
&&
$$
000
FXUS63 KILX 081750
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1150 AM CST SAT NOV 8 2008
.DISCUSSION...
ISSUED 1028 AM CST SAT NOV 8 2008
UPPER LOW MOVING ACROSS THE GREAT LAKES THIS MORNING...WITH PLENTY
CYCLONIC FLOW KEEPING FA UNDER A BLANKET OF LOW CLOUDS. PRESSURE
GRADIENT KEEPING SOMEWHAT GUSTY WINDS IN PLACE AND TEMPERATURES IN
THE UPPER 30S/LOWER 40S. SOME FLURRIES UP CLOSER TO THE LOW...AND
FORECAST GOING VERY WELL. NO UPDATES ANTICIPATED AT THIS TIME.
&&
.AVIATION...
ISSUED 1146 AM CST SAT NOV 8 2008
MVFR CONDITIONS TO CONTINUE THROUGH THE AFTERNOON AND OVERNIGHT
HOURS WITH CIGS BELOW 2KFT IN NRN TERMINALS...AND AROUND 2500FT IN
KDEC. WINDS STAYING GUSTY THROUGH THE DAY AS THE LOW MOVES THROUGH
THE GREAT LAKES. BIG CONCERN WILL BE THE TIMING OF THE RETURN TO
VFR CONDITIONS TOMORROW MORNING. MODELS ARE SPLIT BTWN STAYING OVC
LOW... AND BREAKING IT UP AROUND SUNRISE. HAVE SPLIT THE
DIFFERENCE FOR THE FORECAST IN AN ATTEMPT TO SHOW THE TREND FOR
THE MORNING...THOUGH MAY BE A BIT TOO OPTIMISTIC.
HJS
&&
.PREV DISCUSSION...
ISSUED 208 AM CST SAT NOV 8 2008
CHILLY WEATHER EXPECTED THROUGH MUCH OF THE FORECAST PERIOD...WITH
THE NEXT SIGNIFICANT CHANCE FOR PRECIP ARRIVING LATE MONDAY INTO
TUESDAY.
LATEST UPPER AIR ANALYSIS FEATURES DEEP LOW SPINNING OVER
WISCONSIN...WITH NORTHWESTERLY FLOW NOTED ACROSS MUCH OF THE
MIDWEST. AT THE SURFACE...MAIN COLD FRONT IS NOW WELL TO THE EAST
APPROACHING THE EAST COAST...WHILE ADDITIONAL WEAK IMPULSES
CONTINUE TO ROTATE AROUND THE UPPER LOW. AS A RESULT...WIDESPREAD
CLOUD COVER BLANKETS THE MIDWEST...WITH SCATTERED SPRINKLES/FLURRIES.
SHORT TERM...TODAY THROUGH MONDAY
CLOUDY AND COLD CONDITIONS WILL PREVAIL ACROSS CENTRAL ILLINOIS
TODAY...THANKS TO CONTINUED NORTHWESTERLY FLOW. PLENTY OF LOW-LEVEL
MOISTURE IS NOTED ON 00Z SOUNDINGS FROM BOTH KILX AND KDVN...AS
WELL AS SOUNDINGS UPSTREAM INTO THE NORTHERN PLAINS. MODEL RH
PROFILES INDICATE HIGH RH BELOW 850MB PERSISTING FOR THE ENTIRE
DAY...RESULTING IN OVERCAST CONDITIONS. IN ADDITION...WEAK ENERGY
ROTATING THROUGH THE BROAD NORTHWESTERLY FLOW WILL ENHANCE LIFT
AND PERHAPS TRIGGER A FEW SPRINKLES OR FLURRIES AT TIMES. PRECIP
WILL GENERALLY BE QUITE LIGHT...WITH THE BEST CHANCES FOR ANY
MEASURABLE TOTALS FURTHER NORTH ACROSS NORTHERN ILLINOIS. WITH
CLOUD COVER AND BRISK NORTHWESTERLY WINDS...TEMPS WILL STRUGGLE TO
RISE MUCH FROM EARLY MORNING LOWS. NUMERIC GUIDANCE IS SHOWING A 5
TO 6 DEGREE SPREAD TODAY...WITH THE MAV NUMBERS BEING THE WARMEST.
GIVEN THE POOR PERFORMANCE OF THE MAV YESTERDAY...WILL STICK
CLOSER TO THE COOLER MET GUIDANCE...RESULTING IN HIGHS MAINLY IN
THE UPPER 30S AND LOWER 40S. CONVERSELY...WILL FOLLOW THE WARMER
MAV NUMBERS FOR LOW TEMPS TONIGHT...MAINLY DUE TO CONTINUED CLOUD
COVER PREVENTING LARGE DIURNAL TEMP SWINGS. LOWS TONIGHT WILL
REMAIN IN THE LOWER 30S.
AS UPPER LOW SHIFTS AWAY FROM THE REGION ON SUNDAY...LOW-LEVEL
MOISTURE WILL GRADUALLY DISSIPATE AND SKIES WILL BEGIN TO CLEAR
OUT FROM WEST TO EAST DURING THE AFTERNOON. WILL BE ANOTHER
UNSEASONABLY COOL DAY...BUT GIVEN INCREASED AMOUNT OF
SUNSHINE...THINK HIGH TEMPS WILL BE A COUPLE OF DEGREES WARMER
THAN TODAY. COLDEST NIGHT LOOKS TO BE SETTING UP SUNDAY NIGHT...AS
SKIES CLEAR OUT AND WINDS DIMINISH. MOST AREAS SHOULD EASILY BE
ABLE TO DIP INTO THE MIDDLE TO UPPER 20S.
NEXT SYSTEM OF INTEREST BEGINS TO APPROACH FROM THE SOUTHWEST ON
MONDAY. 00Z NOV 8 NAM-WRF/GFS IN VERY GOOD AGREEMENT CONCERNING
THE HEIGHT FIELDS AND SURFACE PATTERN THROUGH 12Z TUE. BOTH MODELS
SHOW STRONG UPPER JET STREAK PUSHING INTO NORTHERN CALIFORNIA
LATER TODAY...THEN CROSSING THE SOUTHERN ROCKIES AND INDUCING
SURFACE CYCLOGENESIS ACROSS THE SOUTHERN PLAINS ON MONDAY. MODEL
CONSENSUS SUGGESTS WEAK LOW WILL BE LOCATED OVER NORTHEAST TEXAS
BY TUESDAY MORNING...WITH AN INVERTED TROUGH FEATURE EXTENDING
NORTHWARD INTO MISSOURI. MEANWHILE...BOTH THE 12Z ECMWF AND 00Z
CANADIAN ARE STRONGER AND FURTHER NORTH WITH THE LOW. THIS DOES
NOT SUPPORT TRENDS FROM THE PAST FEW DAYS...SO HAVE DECIDED TO
STICK CLOSER TO THE NAM-WRF/GFS AT THIS POINT. END RESULT WILL BE
AN INCREASE IN CLOUD COVER ON MONDAY...WITH PERHAPS A FEW LIGHT
RAIN SHOWERS ARRIVING ACROSS THE FAR SW KILX CWA BY AFTERNOON.
BETTER PRECIP CHANCES ARRIVE MONDAY NIGHT AS ATMOSPHERE MOISTENS
AND LIFT INCREASES. FORECAST SOUNDINGS SUGGEST A RAIN/SNOW MIX
ALONG AND NORTH OF I-72...WITH ALL RAIN FURTHER SOUTH IF THE
NAM-WRF/GFS SOLUTION PANS OUT. IF THE ECMWF TURNS OUT TO BE
CORRECT...PRECIP WOULD MAINLY BE IN THE FORM OF RAIN ACROSS THE
BOARD.
LONG TERM...TUESDAY THROUGH FRIDAY
TUESDAY APPEARS TO BE THE WETTEST DAY OF THE UPCOMING WEEK...AS
INVERTED TROUGH TRACKS THROUGH THE AREA. HAVE HIT POPS HARDEST
ACROSS THE SOUTH...WITH LOWER POPS FURTHER NORTH. COULD SEE A
RAIN/SNOW MIX EARLY IN THE DAY ACROSS THE CENTRAL AND NORTHERN
ZONES...BUT SURFACE TEMPS WILL WARM SUFFICIENTLY TO CHANGE
EVERYTHING TO RAIN BY AFTERNOON. GIVEN LIGHT NATURE OF PRECIP AND
MARGINALLY COLD ATMOSPHERIC PROFILES...AM EXPECTING ONLY A
NUISANCE TYPE SNOW WITH THIS SYSTEM...WITH LITTLE OR NO ACCUMULATION.
AFTER THAT...A SLOW MODERATION IN TEMPS CAN BE EXPECTED THROUGH
THE END OF THE WEEK...WITH TEMPS GRADUALLY RISING BACK TO NEAR
NORMAL IN THE LOWER TO MIDDLE 50S BY THURSDAY AND FRIDAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 081722
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1122 AM CST SAT NOV 8 2008
.DISCUSSION...
249 AM CST
FOCUS WILL REMAIN ON THE MAJOR VORTEX EJECTING NORTHEAST ACROSS SRN
WISCONSIN AND ACROSS CENTRAL LAKE MICH THIS MRNG. MODELS IN STRONG
AGREEMENT THRU FIRST 48 HOURS AT LEAST ON EJECTING UPR LOW FROM LAKE
MICH ACROSS NRN LWR MICHIGAN TODAY INTO EASTERN ONTARIO BY SUNDAY
MRNG. A SECOND UPR VORTEX DEVELOPS IN WESTERN ONTARIO THIS MORNING
AND DOES A FUJIWARA SPIN DOWN OVER THE LAKES ON SUNDAY...SENDING
ANOTHER IMPULSE OF WRAPAROUND COLD CANADIAN AIR INTO NRN IL DURING
THE DAY. WHILE KEEPING CLOUD COVER AND PSBLY SOME MRNG FLURRIES
AROUND ON SUNDAY...THE GRADUAL DEPARTURE TO THE NORTHEAST WILL
DIMINISH SNOW SHOWER FREQUENCY OVER THE NEXT 36 HOURS.
WITH THIS UPR SYSTEM KICKING OUT INTO WRN QUEBEC SUNDAY NIGHT...
SKIES ARE LIKELY TO CLEAR OVERNIGHT. THE ABSENCE OF OUR BLANKET OF
CLOUD COVER WILL ALLOW HEAT TO RADIATE QUICKER...RESULTING IN SOME
OF THE COLDEST OVERNIGHT TEMPERATURES SO FAR THIS FALL.
THE DRY PERIOD ON MONDAY WILL SEE SUNSHINE DIMINISH IN THE AFTERNOON
AS WAA CLOUDINESS ADVANCES NORTHWARD FROM A DEVELOPING SYSTEM IN THE
SRN PLAINS. MODELS HANDLE THIS AGREEABLY THRU 72 HOURS BUT START
DIVERGING AFTER THAT. WITH SFC HIGH PRESSURE ENTRENCHED OVER THE
DAKOTAS AND UPR MS VLY AND CONTINUING TO PUMP COLD AIR INTO THE
GREAT LAKES REGION MONDAY AND TUESDAY...A RATHER BROAD UPR TROF OVER
THE PLAINS AND MID TO LWR MS VLY IS SUCCEEDING IN PUMPING GULF MSTR
UP THE MS VLY AND INTO PARTS OF NRN IL AND INDIANA LATE MON NGT AND
TUESDAY. IF THIS IS THE CASE WITH WARM GULF MSTR OVERRIDING FREEZING
OR NEAR FREEZING TEMPS AT THE SFC...THERE ARISES THE LIKELIHOOD OF
MIXED PCPN TUES THRU WED. THIS CUD BE EITHER RAIN OR SNOW OR BOTH OR
MINGLED WITH SLEET AND PERHAPS SOME FREEZING RAIN.
THE ECMWF IS QUITE A BIT SLOWER THAN THE GFS AND NAM IN SHIFTING UPR
RIDGING EAST OF IL AND COMING UNDER THE OVERRUNNING GULF MSTR
SCENARIO. IT ALSO EXTENDS ITS AMPLITUDE SWD OVER THE SRN PLAINS FROM
A SEPARATE UPR VORTEX LOCATED OVER THE NRN CANADIAN TERRITORIES VS
QUEBEC AS WITH NAM AND GFS. WHILE IMPRESSED WITH THE CLOSE KNIT
ALIGNMENT OF THE GFS WITH THE NAM...PAST MODEL TRENDS HAVE BEEN
EVENTUALLY SIDING WITH OR RESOLVING TOWARD THE ECMWF. BUT FOR
NOW... A GFS/NAM SOLUTION IS PRESENTLY IN EFFECT FOR THE EXTENDED
FORECAST AND WILL REMAIN SO FAR.
RLB
&&
.AVIATION...
1222 PM CDT
1800 UTC TAFS...BROAD CIRCULATION OF LOW PRESSURE WILL CONTINUE TO
BE THE MAIN INFLUENCE OVER THE REGIONS WEATHER THROUGHOUT THE TAF
PERIOD. THE BEST CHANCES FOR ANY PRECIP WILL BE LATE THIS MORNING
THROUGH THE VERY EARLY AFTERNOON AS A SFC AND LOW LEVEL TROF
SWINGS THROUGH THE REGION. THERE STILL WILL REMAIN AN OUTSIDE
CHANCE OF SNOW FLURRIES INTO THE EVENING...BUT AREAL COVERAGE AND
IMPACT WILL BE MINIMAL SO WILL NOT MENTION IN THE TAFS. CEILINGS
WILL BE THE MAIN HINDERANCE WITH MVFR CIGS EXTENDING ALL THE WAY
BACK INTO NEBRASKA. CURRENTLY EXPECT THESE MVFR CIGS OF
1500-2500KFT TO PERSIST THROUGH THE REST OF THE FORECAST PERIOD AS
A LOW LEVEL INVERSION TRAPS ENOUGH MOISTURE IN THE LOW LEVELS OF
THE ATMOSPHERE. THERE ARE A FEW IFR REPORTS OFF TO THE NORTH AND
WEST...BUT THINK THAT THIS WILL STAY OUT OF OUR TAF REGION. WINDS
WILL GRADUALLY VEER FROM THE SOUTHWEST TO THE WEST THIS AFTERNOON
AND THEN TO THE NORTHWEST OVERNIGHT WITH THE GUSTS PERSISTING
THROUGHOUT.
EXPECT MVFR CONDITIONS THROUGHOUT THE TAF PERIOD.
HALBACH
&&
.MARINE...
300 AM CST
LOW PRESSURE OVER THE UPPER GREAT LAKES WILL DEEPEN SLIGHTLY AS
IT MOVES NORTHEAST TO SOUTHERN JAMES BAY SATURDAY EVENING. THE LOW
IS THEN FORECAST TO CONTINUE NORTHEASTWARD TO NEWFOUNDLAND MONDAY.
COLD AIR WILL WRAP AROUND THE BACK SIDE OF THE LOW TODAY...AS A
RIDGE OF HIGH PRESSURE BUILDS OUT OF SOUTH CENTRAL CANADA INTO
THE NORTHERN PLAINS. THIS WILL LEAD TO INCREASING WINDS OVER LAKE
MICHIGAN TODAY...REACHING GALE FORCE OVER THE SOUTHERN PORTIONS OF
THE LAKE. THE PRESSURE GRADIENT...AND WINDS...WILL REMAIN
RELATIVELY STRONG OVER LAKE MICHIGAN THROUGH SUNDAY. FINALLY...BY
EARLY NEXT WEEK...THE RIDGE OF HIGH PRESSURE WILL BUILD OVER LAKE
MICHIGAN...ALLOWING WINDS TO WEAKEN.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL MIDNIGHT SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 5 AM MONDAY.
&&
$$
000
FXUS63 KILX 081631
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1031 AM CST SAT NOV 8 2008
.DISCUSSION...
ISSUED 1028 AM CST SAT NOV 8 2008
UPPER LOW MOVING ACROSS THE GREAT LAKES THIS MORNING...WITH PLENTY
CYCLONIC FLOW KEEPING FA UNDER A BLANKET OF LOW CLOUDS. PRESSURE
GRADIENT KEEPING SOMEWHAT GUSTY WINDS IN PLACE AND TEMPERATURES IN
THE UPPER 30S/LOWER 40S. SOME FLURRIES UP CLOSER TO THE LOW...AND
FORECAST GOING VERY WELL. NO UPDATES ANTICIPATED AT THIS TIME.
HJS
&&
.AVIATION...
ISSUED 553 AM CST SAT NOV 8 2008
GUSTY WEST WINDS EXPECTED TODAY AS STRONG LOW PRESSURE OVER THE
GREAT LAKES REGION DRIFTS INTO EASTERN CANADA. WINDS WILL DIMINISH
THIS EVENING AS THE SYSTEM PULLS AWAY. PREDOMINANTLY MVFR CIGS ARE
EXPECTED THROUGH THE 12Z TAF PERIOD AS MOISTURE CONTINUES TO WRAP
AROUND THE GREAT LAKES STORM SYSTEM. A FEW RAIN OR SNOW SHOWERS
ARE POSSIBLE AS WELL...BUT THEY WILL BE VERY LIGHT AND COVERAGE IS
EXPECTED TO BE TOO LOW TO GO ABOVE VCSH IN THE TAFS.
BAK
&&
.PREV DISCUSSION...
ISSUED 208 AM CST SAT NOV 8 2008
CHILLY WEATHER EXPECTED THROUGH MUCH OF THE FORECAST PERIOD...WITH
THE NEXT SIGNIFICANT CHANCE FOR PRECIP ARRIVING LATE MONDAY INTO
TUESDAY.
LATEST UPPER AIR ANALYSIS FEATURES DEEP LOW SPINNING OVER
WISCONSIN...WITH NORTHWESTERLY FLOW NOTED ACROSS MUCH OF THE
MIDWEST. AT THE SURFACE...MAIN COLD FRONT IS NOW WELL TO THE EAST
APPROACHING THE EAST COAST...WHILE ADDITIONAL WEAK IMPULSES
CONTINUE TO ROTATE AROUND THE UPPER LOW. AS A RESULT...WIDESPREAD
CLOUD COVER BLANKETS THE MIDWEST...WITH SCATTERED SPRINKLES/FLURRIES.
SHORT TERM...TODAY THROUGH MONDAY
CLOUDY AND COLD CONDITIONS WILL PREVAIL ACROSS CENTRAL ILLINOIS
TODAY...THANKS TO CONTINUED NORTHWESTERLY FLOW. PLENTY OF LOW-LEVEL
MOISTURE IS NOTED ON 00Z SOUNDINGS FROM BOTH KILX AND KDVN...AS
WELL AS SOUNDINGS UPSTREAM INTO THE NORTHERN PLAINS. MODEL RH
PROFILES INDICATE HIGH RH BELOW 850MB PERSISTING FOR THE ENTIRE
DAY...RESULTING IN OVERCAST CONDITIONS. IN ADDITION...WEAK ENERGY
ROTATING THROUGH THE BROAD NORTHWESTERLY FLOW WILL ENHANCE LIFT
AND PERHAPS TRIGGER A FEW SPRINKLES OR FLURRIES AT TIMES. PRECIP
WILL GENERALLY BE QUITE LIGHT...WITH THE BEST CHANCES FOR ANY
MEASURABLE TOTALS FURTHER NORTH ACROSS NORTHERN ILLINOIS. WITH
CLOUD COVER AND BRISK NORTHWESTERLY WINDS...TEMPS WILL STRUGGLE TO
RISE MUCH FROM EARLY MORNING LOWS. NUMERIC GUIDANCE IS SHOWING A 5
TO 6 DEGREE SPREAD TODAY...WITH THE MAV NUMBERS BEING THE WARMEST.
GIVEN THE POOR PERFORMANCE OF THE MAV YESTERDAY...WILL STICK
CLOSER TO THE COOLER MET GUIDANCE...RESULTING IN HIGHS MAINLY IN
THE UPPER 30S AND LOWER 40S. CONVERSELY...WILL FOLLOW THE WARMER
MAV NUMBERS FOR LOW TEMPS TONIGHT...MAINLY DUE TO CONTINUED CLOUD
COVER PREVENTING LARGE DIURNAL TEMP SWINGS. LOWS TONIGHT WILL
REMAIN IN THE LOWER 30S.
AS UPPER LOW SHIFTS AWAY FROM THE REGION ON SUNDAY...LOW-LEVEL
MOISTURE WILL GRADUALLY DISSIPATE AND SKIES WILL BEGIN TO CLEAR
OUT FROM WEST TO EAST DURING THE AFTERNOON. WILL BE ANOTHER
UNSEASONABLY COOL DAY...BUT GIVEN INCREASED AMOUNT OF
SUNSHINE...THINK HIGH TEMPS WILL BE A COUPLE OF DEGREES WARMER
THAN TODAY. COLDEST NIGHT LOOKS TO BE SETTING UP SUNDAY NIGHT...AS
SKIES CLEAR OUT AND WINDS DIMINISH. MOST AREAS SHOULD EASILY BE
ABLE TO DIP INTO THE MIDDLE TO UPPER 20S.
NEXT SYSTEM OF INTEREST BEGINS TO APPROACH FROM THE SOUTHWEST ON
MONDAY. 00Z NOV 8 NAM-WRF/GFS IN VERY GOOD AGREEMENT CONCERNING
THE HEIGHT FIELDS AND SURFACE PATTERN THROUGH 12Z TUE. BOTH MODELS
SHOW STRONG UPPER JET STREAK PUSHING INTO NORTHERN CALIFORNIA
LATER TODAY...THEN CROSSING THE SOUTHERN ROCKIES AND INDUCING
SURFACE CYCLOGENESIS ACROSS THE SOUTHERN PLAINS ON MONDAY. MODEL
CONSENSUS SUGGESTS WEAK LOW WILL BE LOCATED OVER NORTHEAST TEXAS
BY TUESDAY MORNING...WITH AN INVERTED TROUGH FEATURE EXTENDING
NORTHWARD INTO MISSOURI. MEANWHILE...BOTH THE 12Z ECMWF AND 00Z
CANADIAN ARE STRONGER AND FURTHER NORTH WITH THE LOW. THIS DOES
NOT SUPPORT TRENDS FROM THE PAST FEW DAYS...SO HAVE DECIDED TO
STICK CLOSER TO THE NAM-WRF/GFS AT THIS POINT. END RESULT WILL BE
AN INCREASE IN CLOUD COVER ON MONDAY...WITH PERHAPS A FEW LIGHT
RAIN SHOWERS ARRIVING ACROSS THE FAR SW KILX CWA BY AFTERNOON.
BETTER PRECIP CHANCES ARRIVE MONDAY NIGHT AS ATMOSPHERE MOISTENS
AND LIFT INCREASES. FORECAST SOUNDINGS SUGGEST A RAIN/SNOW MIX
ALONG AND NORTH OF I-72...WITH ALL RAIN FURTHER SOUTH IF THE
NAM-WRF/GFS SOLUTION PANS OUT. IF THE ECMWF TURNS OUT TO BE
CORRECT...PRECIP WOULD MAINLY BE IN THE FORM OF RAIN ACROSS THE
BOARD.
LONG TERM...TUESDAY THROUGH FRIDAY
TUESDAY APPEARS TO BE THE WETTEST DAY OF THE UPCOMING WEEK...AS
INVERTED TROUGH TRACKS THROUGH THE AREA. HAVE HIT POPS HARDEST
ACROSS THE SOUTH...WITH LOWER POPS FURTHER NORTH. COULD SEE A
RAIN/SNOW MIX EARLY IN THE DAY ACROSS THE CENTRAL AND NORTHERN
ZONES...BUT SURFACE TEMPS WILL WARM SUFFICIENTLY TO CHANGE
EVERYTHING TO RAIN BY AFTERNOON. GIVEN LIGHT NATURE OF PRECIP AND
MARGINALLY COLD ATMOSPHERIC PROFILES...AM EXPECTING ONLY A
NUISANCE TYPE SNOW WITH THIS SYSTEM...WITH LITTLE OR NO ACCUMULATION.
AFTER THAT...A SLOW MODERATION IN TEMPS CAN BE EXPECTED THROUGH
THE END OF THE WEEK...WITH TEMPS GRADUALLY RISING BACK TO NEAR
NORMAL IN THE LOWER TO MIDDLE 50S BY THURSDAY AND FRIDAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 081200
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
600 AM CST SAT NOV 8 2008
.DISCUSSION...
249 AM CST
FOCUS WILL REMAIN ON THE MAJOR VORTEX EJECTING NORTHEAST ACROSS SRN
WISCONSIN AND ACROSS CENTRAL LAKE MICH THIS MRNG. MODELS IN STRONG
AGREEMENT THRU FIRST 48 HOURS AT LEAST ON EJECTING UPR LOW FROM LAKE
MICH ACROSS NRN LWR MICHIGAN TODAY INTO EASTERN ONTARIO BY SUNDAY
MRNG. A SECOND UPR VORTEX DEVELOPS IN WESTERN ONTARIO THIS MORNING
AND DOES A FUJIWARA SPIN DOWN OVER THE LAKES ON SUNDAY...SENDING
ANOTHER IMPULSE OF WRAPAROUND COLD CANADIAN AIR INTO NRN IL DURING
THE DAY. WHILE KEEPING CLOUD COVER AND PSBLY SOME MRNG FLURRIES
AROUND ON SUNDAY...THE GRADUAL DEPARTURE TO THE NORTHEAST WILL
DIMINISH SNOW SHOWER FREQUENCY OVER THE NEXT 36 HOURS.
WITH THIS UPR SYSTEM KICKING OUT INTO WRN QUEBEC SUNDAY NIGHT...
SKIES ARE LIKELY TO CLEAR OVERNIGHT. THE ABSENCE OF OUR BLANKET OF
CLOUD COVER WILL ALLOW HEAT TO RADIATE QUICKER...RESULTING IN SOME
OF THE COLDEST OVERNIGHT TEMPERATURES SO FAR THIS FALL.
THE DRY PERIOD ON MONDAY WILL SEE SUNSHINE DIMINISH IN THE AFTERNOON
AS WAA CLOUDINESS ADVANCES NORTHWARD FROM A DEVELOPING SYSTEM IN THE
SRN PLAINS. MODELS HANDLE THIS AGREEABLY THRU 72 HOURS BUT START
DIVERGING AFTER THAT. WITH SFC HIGH PRESSURE ENTRENCHED OVER THE
DAKOTAS AND UPR MS VLY AND CONTINUING TO PUMP COLD AIR INTO THE
GREAT LAKES REGION MONDAY AND TUESDAY...A RATHER BROAD UPR TROF OVER
THE PLAINS AND MID TO LWR MS VLY IS SUCCEEDING IN PUMPING GULF MSTR
UP THE MS VLY AND INTO PARTS OF NRN IL AND INDIANA LATE MON NGT AND
TUESDAY. IF THIS IS THE CASE WITH WARM GULF MSTR OVERRIDING FREEZING
OR NEAR FREEZING TEMPS AT THE SFC...THERE ARISES THE LIKELIHOOD OF
MIXED PCPN TUES THRU WED. THIS CUD BE EITHER RAIN OR SNOW OR BOTH OR
MINGLED WITH SLEET AND PERHAPS SOME FREEZING RAIN.
THE ECMWF IS QUITE A BIT SLOWER THAN THE GFS AND NAM IN SHIFTING UPR
RIDGING EAST OF IL AND COMING UNDER THE OVERRUNNING GULF MSTR
SCENARIO. IT ALSO EXTENDS ITS AMPLITUDE SWD OVER THE SRN PLAINS FROM
A SEPARATE UPR VORTEX LOCATED OVER THE NRN CANADIAN TERRITORIES VS
QUEBEC AS WITH NAM AND GFS. WHILE IMPRESSED WITH THE CLOSE KNIT
ALIGNMENT OF THE GFS WITH THE NAM...PAST MODEL TRENDS HAVE BEEN
EVENTUALLY SIDING WITH OR RESOLVING TOWARD THE ECMWF. BUT FOR
NOW... A GFS/NAM SOLUTION IS PRESENTLY IN EFFECT FOR THE EXTENDED
FORECAST AND WILL REMAIN SO FAR.
RLB
&&
.AVIATION...
1200 UTC TAFS...ONLY SOME MINOR REFINEMENTS TO THE GOING TAFS.
WRAP AROUND RAIN/SNOW SHOWERS CONTINUE TO ROTATE AROUND THE LARGE
LOW PRESSURE SYSTEM AS IT MOVES THROUGH NORTHERN WISCONSIN. FLIGHT
CONDITIONS ACROSS THE AREA ARE LARGELY MVFR WITH CIGS GENERALLY
ARND 015-025KFT...BUT LATEST METARS HAVE SHOWN SOME SITES OCNLY
DROPPING BLW 1000FT...SO HAVE ADDED TEMPO IFR CIGS FOR THE FIRST 2
HRS OF THE NEW TAF PERIOD UNTIL SOME MODEST DAYTIME WARMING SHOULD
ALLOW CIGS TO LIFT SOMEWHAT...BUT WILL REMAIN MVFR THROUGH THE 24
HR PERIOD. CIGS SHOULD IMPROVE BY TOMORROW MORNING AS THE UPPER
LOW BEGINS TO PULL AWAY FROM THE REGION.
STRONGER COLD ADVECTION AND A MINOR WIND SHIFT SHOULD OCCUR BY
EARLY AFTERNOON AS A SHORT WAVE ROTATING AROUND THE WRN PERIPHERY
OF THE UPPER LOW PASSES OUT OF THE UPPER MISSISSIPPI VALLEY AND
TRACKS ACROSS NRN IL. THE PASSAGE OF THE ASSD SFC TROF WILL BE
ACCOMPANIED BY A WIND SHIFT TO 290-300 DEGREES AND CONTINUED
FREQUENT WIND GUSTS INTO THE MIDDLE TO UPPER 20S KTS...AND OCNL
GUSTS TO AROUND 30KT.
PCPN WILL CONTINUE TO BE A MIXED BAG OF RA/SN AS TEMPS HOVER JUST
ABOVE FREEZING...BUT ENHANCED DYNAMIC COOLING WITH THE UPPER SHORT
WAVE AND COLD ADVECTION BEHIND THE SFC TROF SHOULD BE SUFFICIENT
TO ALLOW THE PCPN TO CHANGE OVER TO ALL SHSN FOR BRIEF PERIODS.
WHILE PCPN WILL BE HEAVY ENOUGH TO WET RUNWAYS...THE GROUND WILL
REMAIN MUCH TO WARM TO ALLOW ANY ACCUMULATIONS.
KREIN
&&
.MARINE...
300 AM CST
LOW PRESSURE OVER THE UPPER GREAT LAKES WILL DEEPEN SLIGHTLY AS
IT MOVES NORTHEAST TO SOUTHERN JAMES BAY SATURDAY EVENING. THE LOW
IS THEN FORECAST TO CONTINUE NORTHEASTWARD TO NEWFOUNDLAND MONDAY.
COLD AIR WILL WRAP AROUND THE BACK SIDE OF THE LOW TODAY...AS A
RIDGE OF HIGH PRESSURE BUILDS OUT OF SOUTH CENTRAL CANADA INTO
THE NORTHERN PLAINS. THIS WILL LEAD TO INCREASING WINDS OVER LAKE
MICHIGAN TODAY...REACHING GALE FORCE OVER THE SOUTHERN PORTIONS OF
THE LAKE. THE PRESSURE GRADIENT...AND WINDS...WILL REMAIN
RELATIVELY STRONG OVER LAKE MICHIGAN THROUGH SUNDAY. FINALLY...BY
EARLY NEXT WEEK...THE RIDGE OF HIGH PRESSURE WILL BUILD OVER LAKE
MICHIGAN...ALLOWING WINDS TO WEAKEN.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON SATURDAY TO
MIDNIGHT SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 5 AM MONDAY.
&&
$$
000
FXUS63 KILX 081155
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
555 AM CST SAT NOV 8 2008
.DISCUSSION...
ISSUED 208 AM CST SAT NOV 8 2008
CHILLY WEATHER EXPECTED THROUGH MUCH OF THE FORECAST PERIOD...WITH
THE NEXT SIGNIFICANT CHANCE FOR PRECIP ARRIVING LATE MONDAY INTO
TUESDAY.
LATEST UPPER AIR ANALYSIS FEATURES DEEP LOW SPINNING OVER
WISCONSIN...WITH NORTHWESTERLY FLOW NOTED ACROSS MUCH OF THE
MIDWEST. AT THE SURFACE...MAIN COLD FRONT IS NOW WELL TO THE EAST
APPROACHING THE EAST COAST...WHILE ADDITIONAL WEAK IMPULSES
CONTINUE TO ROTATE AROUND THE UPPER LOW. AS A RESULT...WIDESPREAD
CLOUD COVER BLANKETS THE MIDWEST...WITH SCATTERED SPRINKLES/FLURRIES.
SHORT TERM...TODAY THROUGH MONDAY
CLOUDY AND COLD CONDITIONS WILL PREVAIL ACROSS CENTRAL ILLINOIS
TODAY...THANKS TO CONTINUED NORTHWESTERLY FLOW. PLENTY OF LOW-LEVEL
MOISTURE IS NOTED ON 00Z SOUNDINGS FROM BOTH KILX AND KDVN...AS
WELL AS SOUNDINGS UPSTREAM INTO THE NORTHERN PLAINS. MODEL RH
PROFILES INDICATE HIGH RH BELOW 850MB PERSISTING FOR THE ENTIRE
DAY...RESULTING IN OVERCAST CONDITIONS. IN ADDITION...WEAK ENERGY
ROTATING THROUGH THE BROAD NORTHWESTERLY FLOW WILL ENHANCE LIFT
AND PERHAPS TRIGGER A FEW SPRINKLES OR FLURRIES AT TIMES. PRECIP
WILL GENERALLY BE QUITE LIGHT...WITH THE BEST CHANCES FOR ANY
MEASURABLE TOTALS FURTHER NORTH ACROSS NORTHERN ILLINOIS. WITH
CLOUD COVER AND BRISK NORTHWESTERLY WINDS...TEMPS WILL STRUGGLE TO
RISE MUCH FROM EARLY MORNING LOWS. NUMERIC GUIDANCE IS SHOWING A 5
TO 6 DEGREE SPREAD TODAY...WITH THE MAV NUMBERS BEING THE WARMEST.
GIVEN THE POOR PERFORMANCE OF THE MAV YESTERDAY...WILL STICK
CLOSER TO THE COOLER MET GUIDANCE...RESULTING IN HIGHS MAINLY IN
THE UPPER 30S AND LOWER 40S. CONVERSELY...WILL FOLLOW THE WARMER
MAV NUMBERS FOR LOW TEMPS TONIGHT...MAINLY DUE TO CONTINUED CLOUD
COVER PREVENTING LARGE DIURNAL TEMP SWINGS. LOWS TONIGHT WILL
REMAIN IN THE LOWER 30S.
AS UPPER LOW SHIFTS AWAY FROM THE REGION ON SUNDAY...LOW-LEVEL
MOISTURE WILL GRADUALLY DISSIPATE AND SKIES WILL BEGIN TO CLEAR
OUT FROM WEST TO EAST DURING THE AFTERNOON. WILL BE ANOTHER
UNSEASONABLY COOL DAY...BUT GIVEN INCREASED AMOUNT OF
SUNSHINE...THINK HIGH TEMPS WILL BE A COUPLE OF DEGREES WARMER
THAN TODAY. COLDEST NIGHT LOOKS TO BE SETTING UP SUNDAY NIGHT...AS
SKIES CLEAR OUT AND WINDS DIMINISH. MOST AREAS SHOULD EASILY BE
ABLE TO DIP INTO THE MIDDLE TO UPPER 20S.
NEXT SYSTEM OF INTEREST BEGINS TO APPROACH FROM THE SOUTHWEST ON
MONDAY. 00Z NOV 8 NAM-WRF/GFS IN VERY GOOD AGREEMENT CONCERNING
THE HEIGHT FIELDS AND SURFACE PATTERN THROUGH 12Z TUE. BOTH MODELS
SHOW STRONG UPPER JET STREAK PUSHING INTO NORTHERN CALIFORNIA
LATER TODAY...THEN CROSSING THE SOUTHERN ROCKIES AND INDUCING
SURFACE CYCLOGENESIS ACROSS THE SOUTHERN PLAINS ON MONDAY. MODEL
CONSENSUS SUGGESTS WEAK LOW WILL BE LOCATED OVER NORTHEAST TEXAS
BY TUESDAY MORNING...WITH AN INVERTED TROUGH FEATURE EXTENDING
NORTHWARD INTO MISSOURI. MEANWHILE...BOTH THE 12Z ECMWF AND 00Z
CANADIAN ARE STRONGER AND FURTHER NORTH WITH THE LOW. THIS DOES
NOT SUPPORT TRENDS FROM THE PAST FEW DAYS...SO HAVE DECIDED TO
STICK CLOSER TO THE NAM-WRF/GFS AT THIS POINT. END RESULT WILL BE
AN INCREASE IN CLOUD COVER ON MONDAY...WITH PERHAPS A FEW LIGHT
RAIN SHOWERS ARRIVING ACROSS THE FAR SW KILX CWA BY AFTERNOON.
BETTER PRECIP CHANCES ARRIVE MONDAY NIGHT AS ATMOSPHERE MOISTENS
AND LIFT INCREASES. FORECAST SOUNDINGS SUGGEST A RAIN/SNOW MIX
ALONG AND NORTH OF I-72...WITH ALL RAIN FURTHER SOUTH IF THE
NAM-WRF/GFS SOLUTION PANS OUT. IF THE ECMWF TURNS OUT TO BE
CORRECT...PRECIP WOULD MAINLY BE IN THE FORM OF RAIN ACROSS THE
BOARD.
LONG TERM...TUESDAY THROUGH FRIDAY
TUESDAY APPEARS TO BE THE WETTEST DAY OF THE UPCOMING WEEK...AS
INVERTED TROUGH TRACKS THROUGH THE AREA. HAVE HIT POPS HARDEST
ACROSS THE SOUTH...WITH LOWER POPS FURTHER NORTH. COULD SEE A
RAIN/SNOW MIX EARLY IN THE DAY ACROSS THE CENTRAL AND NORTHERN
ZONES...BUT SURFACE TEMPS WILL WARM SUFFICIENTLY TO CHANGE
EVERYTHING TO RAIN BY AFTERNOON. GIVEN LIGHT NATURE OF PRECIP AND
MARGINALLY COLD ATMOSPHERIC PROFILES...AM EXPECTING ONLY A
NUISANCE TYPE SNOW WITH THIS SYSTEM...WITH LITTLE OR NO ACCUMULATION.
AFTER THAT...A SLOW MODERATION IN TEMPS CAN BE EXPECTED THROUGH
THE END OF THE WEEK...WITH TEMPS GRADUALLY RISING BACK TO NEAR
NORMAL IN THE LOWER TO MIDDLE 50S BY THURSDAY AND FRIDAY.
&&
.AVIATION...
ISSUED 553 AM CST SAT NOV 8 2008
GUSTY WEST WINDS EXPECTED TODAY AS STRONG LOW PRESSURE OVER THE
GREAT LAKES REGION DRIFTS INTO EASTERN CANADA. WINDS WILL DIMINISH
THIS EVENING AS THE SYSTEM PULLS AWAY. PREDOMINANTLY MVFR CIGS ARE
EXPECTED THROUGH THE 12Z TAF PERIOD AS MOISTURE CONTINUES TO WRAP
AROUND THE GREAT LAKES STORM SYSTEM. A FEW RAIN OR SNOW SHOWERS
ARE POSSIBLE AS WELL...BUT THEY WILL BE VERY LIGHT AND COVERAGE IS
EXPECTED TO BE TOO LOW TO GO ABOVE VCSH IN THE TAFS.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 080903
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
303 AM CST SAT NOV 8 2008
.DISCUSSION...
249 AM CST
FOCUS WILL REMAIN ON THE MAJOR VORTEX EJECTING NORTHEAST ACROSS SRN
WISCONSIN AND ACROSS CENTRAL LAKE MICH THIS MRNG. MODELS IN STRONG
AGREEMENT THRU FIRST 48 HOURS AT LEAST ON EJECTING UPR LOW FROM LAKE
MICH ACROSS NRN LWR MICHIGAN TODAY INTO EASTERN ONTARIO BY SUNDAY
MRNG. A SECOND UPR VORTEX DEVELOPS IN WESTERN ONTARIO THIS MORNING
AND DOES A FUJIWARA SPIN DOWN OVER THE LAKES ON SUNDAY...SENDING
ANOTHER IMPULSE OF WRAPAROUND COLD CANADIAN AIR INTO NRN IL DURING
THE DAY. WHILE KEEPING CLOUD COVER AND PSBLY SOME MRNG FLURRIES
AROUND ON SUNDAY...THE GRADUAL DEPARTURE TO THE NORTHEAST WILL
DIMINISH SNOW SHOWER FREQUENCY OVER THE NEXT 36 HOURS.
WITH THIS UPR SYSTEM KICKING OUT INTO WRN QUEBEC SUNDAY NIGHT...
SKIES ARE LIKELY TO CLEAR OVERNIGHT. THE ABSENCE OF OUR BLANKET OF
CLOUD COVER WILL ALLOW HEAT TO RADIATE QUICKER...RESULTING IN SOME
OF THE COLDEST OVERNIGHT TEMPERATURES SO FAR THIS FALL.
THE DRY PERIOD ON MONDAY WILL SEE SUNSHINE DIMINISH IN THE AFTERNOON
AS WAA CLOUDINESS ADVANCES NORTHWARD FROM A DEVELOPING SYSTEM IN THE
SRN PLAINS. MODELS HANDLE THIS AGREEABLY THRU 72 HOURS BUT START
DIVERGING AFTER THAT. WITH SFC HIGH PRESSURE ENTRENCHED OVER THE
DAKOTAS AND UPR MS VLY AND CONTINUING TO PUMP COLD AIR INTO THE
GREAT LAKES REGION MONDAY AND TUESDAY...A RATHER BROAD UPR TROF OVER
THE PLAINS AND MID TO LWR MS VLY IS SUCCEEDING IN PUMPING GULF MSTR
UP THE MS VLY AND INTO PARTS OF NRN IL AND INDIANA LATE MON NGT AND
TUESDAY. IF THIS IS THE CASE WITH WARM GULF MSTR OVERRIDING FREEZING
OR NEAR FREEZING TEMPS AT THE SFC...THERE ARISES THE LIKELIHOOD OF
MIXED PCPN TUES THRU WED. THIS CUD BE EITHER RAIN OR SNOW OR BOTH OR
MINGLED WITH SLEET AND PERHAPS SOME FREEZING RAIN.
THE ECMWF IS QUITE A BIT SLOWER THAN THE GFS AND NAM IN SHIFTING UPR
RIDGING EAST OF IL AND COMING UNDER THE OVERRUNNING GULF MSTR
SCENARIO. IT ALSO EXTENDS ITS AMPLITUDE SWD OVER THE SRN PLAINS FROM
A SEPARATE UPR VORTEX LOCATED OVER THE NRN CANADIAN TERRITORIES VS
QUEBEC AS WITH NAM AND GFS. WHILE IMPRESSED WITH THE CLOSE KNIT
ALIGNMENT OF THE GFS WITH THE NAM...PAST MODEL TRENDS HAVE BEEN
EVENTUALLY SIDING WITH OR RESOLVING TOWARD THE ECMWF. BUT FOR
NOW... A GFS/NAM SOLUTION IS PRESENTLY IN EFFECT FOR THE EXTENDED
FORECAST AND WILL REMAIN SO FAR.
RLB
&&
.AVIATION...
0600 UTC TAFS...NO BIG CHANGES PLANNED TO GOING TAFS. WRAP AROUND
RAIN/SNOW SHOWERS CONTINUE TO PIVOT AROUND LARGE CYCLONE OVER THE
WESTERN GREAT LAKES. VSBYS LARGELY STAYING VFR...THOUGH HAVE
SPORADICALLY DROPPED TO MVFR AND EVEN IFR IN SPOTS WITH THE HEAVIER
SHOWERS. HAVE ONLY TEMPO-ED FOR BRIEF PERIOD OF MVFR VSBYS EARLY
IN THE PERIOD AS MORE PRONOUNCED SHORTWAVE ROTATING AROUND THE
SYSTEM TRAVERSES THE AREA. CYCLONIC LOW LEVEL FLOW...LOW LEVEL
COLD AIR ADVECTION...AND LINGERING LOW LEVEL MOISTURE COULD BE
ENOUGH FOR SPITS OF FLURRIES AND POSSIBLY EVEN A LIGHT SNOW SHOWER
PRETTY MUCH ANYTIME THE NEXT 24-30 HOURS...BUT AVIATION IMPACT
SHOULD BE MINIMAL SO KEPT MENTION OUT OF THE TAFS BEYOND TONIGHT.
SOLID LOW END MVFR DECK EXISTS UPSTREAM OVER IOWA AND SEE NO
REASON WHY THIS WON`T ROTATE EASTWARD INTO THE AREA WITH CIGS BLO
2K FT LIKELY LATE TONIGHT THROUGH AT LEAST FIRST HALF OF
SATURDAY...WITH SOME SLIGHT IMPROVEMENT POSSIBLE IN THE AFTERNOON.
04Z SURFACE ANALYSIS SHOWS A SURFACE TROUGH ENTERING NW IL...MUCH
MORE PRONOUNCED THAN INDICATED BY MODELS. HAVE INCLUDED A BIT OF A
WIND SHIFT THAN MOS/MODELS WOULD SUGGEST BY SUNRISE. WINDS SHOULD
INCREASE SOME AND BECOME QUITE GUSTY SATURDAY IN STEEP LOW LEVEL
LAPSE RATE ENVIRONMENT ASSOCIATED WITH THE COLD AIR ADVECTION.
FORECAST SOUNDINGS SUGGEST MIXING INTO 30KT FLOW...SO GUSTS AOA
25KT LOOK LIKE A GOOD BET. WINDS/GUSTINESS MAY TEND TO SUBSIDE A
SMIDGE AFTER SUNSET SAT EVENING...THOUGH GRADIENT SHOULD REMAIN
TIGHT ENOUGH TO MAINTAIN A MODERATELY STRONG WIND INTO THE NIGHT.
IZZI
&&
.MARINE...
300 AM CST
LOW PRESSURE OVER THE UPPER GREAT LAKES WILL DEEPEN SLIGHTLY AS
IT MOVES NORTHEAST TO SOUTHERN JAMES BAY SATURDAY EVENING. THE LOW
IS THEN FORECAST TO CONTINUE NORTHEASTWARD TO NEWFOUNDLAND MONDAY.
COLD AIR WILL WRAP AROUND THE BACK SIDE OF THE LOW TODAY...AS A
RIDGE OF HIGH PRESSURE BUILDS OUT OF SOUTH CENTRAL CANADA INTO
THE NORTHERN PLAINS. THIS WILL LEAD TO INCREASING WINDS OVER LAKE
MICHIGAN TODAY...REACHING GALE FORCE OVER THE SOUTHERN PORTIONS OF
THE LAKE. THE PRESSURE GRADIENT...AND WINDS...WILL REMAIN
RELATIVELY STRONG OVER LAKE MICHIGAN THROUGH SUNDAY. FINALLY...BY
EARLY NEXT WEEK...THE RIDGE OF HIGH PRESSURE WILL BUILD OVER LAKE
MICHIGAN...ALLOWING WINDS TO WEAKEN.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON SATURDAY TO
MIDNIGHT SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 AM SUNDAY.
&&
$$
000
FXUS63 KLOT 080853
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
253 AM CST SAT NOV 8 2008
.DISCUSSION...
249 AM CST
FOCUS WILL REMAIN ON THE MAJOR VORTEX EJECTING NORTHEAST ACROSS SRN
WISCONSIN AND ACROSS CENTRAL LAKE MICH THIS MRNG. MODELS IN STRONG
AGREEMENT THRU FIRST 48 HOURS AT LEAST ON EJECTING UPR LOW FROM LAKE
MICH ACROSS NRN LWR MICHIGAN TODAY INTO EASTERN ONTARIO BY SUNDAY
MRNG. A SECOND UPR VORTEX DEVELOPS IN WESTERN ONTARIO THIS MORNING
AND DOES A FUJIWARA SPIN DOWN OVER THE LAKES ON SUNDAY...SENDING
ANOTHER IMPULSE OF WRAPAROUND COLD CANADIAN AIR INTO NRN IL DURING
THE DAY. WHILE KEEPING CLOUD COVER AND PSBLY SOME MRNG FLURRIES
AROUND ON SUNDAY...THE GRADUAL DEPARTURE TO THE NORTHEAST WILL
DIMINISH SNOW SHOWER FREQUENCY OVER THE NEXT 36 HOURS.
WITH THIS UPR SYSTEM KICKING OUT INTO WRN QUEBEC SUNDAY NIGHT...
SKIES ARE LIKELY TO CLEAR OVERNIGHT. THE ABSENCE OF OUR BLANKET OF
CLOUD COVER WILL ALLOW HEAT TO RADIATE QUICKER...RESULTING IN SOME
OF THE COLDEST OVERNIGHT TEMPERATURES SO FAR THIS FALL.
THE DRY PERIOD ON MONDAY WILL SEE SUNSHINE DIMINISH IN THE AFTERNOON
AS WAA CLOUDINESS ADVANCES NORTHWARD FROM A DEVELOPING SYSTEM IN THE
SRN PLAINS. MODELS HANDLE THIS AGREEABLY THRU 72 HOURS BUT START
DIVERGING AFTER THAT. WITH SFC HIGH PRESSURE ENTRENCED OVER THE
DAKOTAS AND UPR MS VLY AND CONTINUING TO PUMP COLD AIR INTO THE
GREAT LAKES REGION MONDAY AND TUESDAY...A RATHER BROAD UPR TROF OVER
THE PLAINS AND MID TO LWR MS VLY IS SUCCEEDING IN PUMPING GULF MSTR
UP THE MS VLY AND INTO PARTS OF NRN IL AND INDIANA LATE MON NGT AND
TUESDAY. IF THIS IS THE CASE WITH WARM GULF MSTR OVERRIDING FREEZING
OR NEAR FREEZING TEMPS AT THE SFC...THERE ARISES THE LIKELIHOOD OF
MIXED PCPN TUES THRU WED. THIS CUD BE EITHER RAIN OR SNOW OR BOTH OR
MINGLED WITH SLEET AND PERHAPS SOME FREEZING RAIN.
THE ECMWF IS QUITE A BIT SLOWER THAN THE GFS AND NAM IN SHIFTING UPR
RIDGING EAST OF IL AND COMING UNDER THE OVERRUNNING GULF MSTR
SCENARIO. IT ALSO EXTENDS ITS AMPLITUDE SWD OVER THE SRN PLAINS FROM
A SEPARATE UPR VORTEX LOCATED OVER THE NRN CANADIAN TERRITORIES VS
QUEBEC AS WITH NAM AND GFS. WHILE IMPRESSED WITH THE CLOSE KNIT
ALIGNMENT OF THE GFS WITH THE NAM...PAST MODEL TRENDS HAVE BEEN
EVENTUALLY SIDING WITH OR RESOLVING TOWARD THE ECMWF. BUT FOR
NOW... A GFS/NAM SOLUTION IS PRESENTLY IN EFFECT FOR THE EXTENDED
FORECAST AND WILL REMAIN SO FAR.
RLB
&&
.AVIATION...
0600 UTC TAFS...NO BIG CHANGES PLANNED TO GOING TAFS. WRAP AROUND
RAIN/SNOW SHOWERS CONTINUE TO PIVOT AROUND LARGE CYCLONE OVER THE
WESTERN GREAT LAKES. VSBYS LARGELY STAYING VFR...THOUGH HAVE
SPORADICALLY DROPPED TO MVFR AND EVEN IFR IN SPOTS WITH THE HEAVIER
SHOWERS. HAVE ONLY TEMPO-ED FOR BRIEF PERIOD OF MVFR VSBYS EARLY
IN THE PERIOD AS MORE PRONOUNCED SHORTWAVE ROTATING AROUND THE
SYSTEM TRAVERSES THE AREA. CYCLONIC LOW LEVEL FLOW...LOW LEVEL
COLD AIR ADVECTION...AND LINGERING LOW LEVEL MOISTURE COULD BE
ENOUGH FOR SPITS OF FLURRIES AND POSSIBLY EVEN A LIGHT SNOW SHOWER
PRETTY MUCH ANYTIME THE NEXT 24-30 HOURS...BUT AVIATION IMPACT
SHOULD BE MINIMAL SO KEPT MENTION OUT OF THE TAFS BEYOND TONIGHT.
SOLID LOW END MVFR DECK EXISTS UPSTREAM OVER IOWA AND SEE NO
REASON WHY THIS WON`T ROTATE EASTWARD INTO THE AREA WITH CIGS BLO
2K FT LIKELY LATE TONIGHT THROUGH AT LEAST FIRST HALF OF
SATURDAY...WITH SOME SLIGHT IMPROVEMENT POSSIBLE IN THE AFTERNOON.
04Z SURFACE ANALYSIS SHOWS A SURFACE TROUGH ENTERING NW IL...MUCH
MORE PRONOUNCED THAN INDICATED BY MODELS. HAVE INCLUDED A BIT OF A
WIND SHIFT THAN MOS/MODELS WOULD SUGGEST BY SUNRISE. WINDS SHOULD
INCREASE SOME AND BECOME QUITE GUSTY SATURDAY IN STEEP LOW LEVEL
LAPSE RATE ENVIRONMENT ASSOCIATED WITH THE COLD AIR ADVECTION.
FORECAST SOUNDINGS SUGGEST MIXING INTO 30KT FLOW...SO GUSTS AOA
25KT LOOK LIKE A GOOD BET. WINDS/GUSTINESS MAY TEND TO SUBSIDE A
SMIDGE AFTER SUNSET SAT EVENING...THOUGH GRADIENT SHOULD REMAIN
TIGHT ENOUGH TO MAINTAIN A MODERATELY STRONG WIND INTO THE NIGHT.
IZZI
&&
.MARINE...
113 PM CST
A LOW WITH A PRESSURE WAS OVER SOUTHERN MINNESOTA THIS MORNING.
THIS LOW WILL MOVE NORTHEAST TO SOUTHERN ONTARIO BY SATURDAY
AFTERNOON. THIS LOW WILL HAVE PRESSURE LOW ENOUGH TO CREATE A
STRONG WIND OVER LAKE MICHIGAN. THERE MAY BE GALES SATURDAY. THE
WIND WILL DECREASE SLIGHTLY SUNDAY AS THEY TURN WEST. THE HIGH
WILL DEVELOP OVER NORTHERN MANITOBA WILL EXTEND SOUTH ACROSS THE
GREAT PLAINS TO OKLAHOMA BY SATURDAY EVENING.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON SATURDAY TO
MIDNIGHT SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 AM SUNDAY.
&&
$$
000
FXUS63 KILX 080808
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
208 AM CST SAT NOV 8 2008
.DISCUSSION...
ISSUED 208 AM CST SAT NOV 8 2008
CHILLY WEATHER EXPECTED THROUGH MUCH OF THE FORECAST PERIOD...WITH
THE NEXT SIGNIFICANT CHANCE FOR PRECIP ARRIVING LATE MONDAY INTO
TUESDAY.
LATEST UPPER AIR ANALYSIS FEATURES DEEP LOW SPINNING OVER
WISCONSIN...WITH NORTHWESTERLY FLOW NOTED ACROSS MUCH OF THE
MIDWEST. AT THE SURFACE...MAIN COLD FRONT IS NOW WELL TO THE EAST
APPROACHING THE EAST COAST...WHILE ADDITIONAL WEAK IMPULSES
CONTINUE TO ROTATE AROUND THE UPPER LOW. AS A RESULT...WIDESPREAD
CLOUD COVER BLANKETS THE MIDWEST...WITH SCATTERED SPRINKLES/FLURRIES.
SHORT TERM...TODAY THROUGH MONDAY
CLOUDY AND COLD CONDITIONS WILL PREVAIL ACROSS CENTRAL ILLINOIS
TODAY...THANKS TO CONTINUED NORTHWESTERLY FLOW. PLENTY OF LOW-LEVEL
MOISTURE IS NOTED ON 00Z SOUNDINGS FROM BOTH KILX AND KDVN...AS
WELL AS SOUNDINGS UPSTREAM INTO THE NORTHERN PLAINS. MODEL RH
PROFILES INDICATE HIGH RH BELOW 850MB PERSISTING FOR THE ENTIRE
DAY...RESULTING IN OVERCAST CONDITIONS. IN ADDITION...WEAK ENERGY
ROTATING THROUGH THE BROAD NORTHWESTERLY FLOW WILL ENHANCE LIFT
AND PERHAPS TRIGGER A FEW SPRINKLES OR FLURRIES AT TIMES. PRECIP
WILL GENERALLY BE QUITE LIGHT...WITH THE BEST CHANCES FOR ANY
MEASURABLE TOTALS FURTHER NORTH ACROSS NORTHERN ILLINOIS. WITH
CLOUD COVER AND BRISK NORTHWESTERLY WINDS...TEMPS WILL STRUGGLE TO
RISE MUCH FROM EARLY MORNING LOWS. NUMERIC GUIDANCE IS SHOWING A 5
TO 6 DEGREE SPREAD TODAY...WITH THE MAV NUMBERS BEING THE WARMEST.
GIVEN THE POOR PERFORMANCE OF THE MAV YESTERDAY...WILL STICK
CLOSER TO THE COOLER MET GUIDANCE...RESULTING IN HIGHS MAINLY IN
THE UPPER 30S AND LOWER 40S. CONVERSELY...WILL FOLLOW THE WARMER
MAV NUMBERS FOR LOW TEMPS TONIGHT...MAINLY DUE TO CONTINUED CLOUD
COVER PREVENTING LARGE DIURNAL TEMP SWINGS. LOWS TONIGHT WILL
REMAIN IN THE LOWER 30S.
AS UPPER LOW SHIFTS AWAY FROM THE REGION ON SUNDAY...LOW-LEVEL
MOISTURE WILL GRADUALLY DISSIPATE AND SKIES WILL BEGIN TO CLEAR
OUT FROM WEST TO EAST DURING THE AFTERNOON. WILL BE ANOTHER
UNSEASONABLY COOL DAY...BUT GIVEN INCREASED AMOUNT OF
SUNSHINE...THINK HIGH TEMPS WILL BE A COUPLE OF DEGREES WARMER
THAN TODAY. COLDEST NIGHT LOOKS TO BE SETTING UP SUNDAY NIGHT...AS
SKIES CLEAR OUT AND WINDS DIMINISH. MOST AREAS SHOULD EASILY BE
ABLE TO DIP INTO THE MIDDLE TO UPPER 20S.
NEXT SYSTEM OF INTEREST BEGINS TO APPROACH FROM THE SOUTHWEST ON
MONDAY. 00Z NOV 8 NAM-WRF/GFS IN VERY GOOD AGREEMENT CONCERNING
THE HEIGHT FIELDS AND SURFACE PATTERN THROUGH 12Z TUE. BOTH MODELS
SHOW STRONG UPPER JET STREAK PUSHING INTO NORTHERN CALIFORNIA
LATER TODAY...THEN CROSSING THE SOUTHERN ROCKIES AND INDUCING
SURFACE CYCLOGENESIS ACROSS THE SOUTHERN PLAINS ON MONDAY. MODEL
CONSENSUS SUGGESTS WEAK LOW WILL BE LOCATED OVER NORTHEAST TEXAS
BY TUESDAY MORNING...WITH AN INVERTED TROUGH FEATURE EXTENDING
NORTHWARD INTO MISSOURI. MEANWHILE...BOTH THE 12Z ECMWF AND 00Z
CANADIAN ARE STRONGER AND FURTHER NORTH WITH THE LOW. THIS DOES
NOT SUPPORT TRENDS FROM THE PAST FEW DAYS...SO HAVE DECIDED TO
STICK CLOSER TO THE NAM-WRF/GFS AT THIS POINT. END RESULT WILL BE
AN INCREASE IN CLOUD COVER ON MONDAY...WITH PERHAPS A FEW LIGHT
RAIN SHOWERS ARRIVING ACROSS THE FAR SW KILX CWA BY AFTERNOON.
BETTER PRECIP CHANCES ARRIVE MONDAY NIGHT AS ATMOSPHERE MOISTENS
AND LIFT INCREASES. FORECAST SOUNDINGS SUGGEST A RAIN/SNOW MIX
ALONG AND NORTH OF I-72...WITH ALL RAIN FURTHER SOUTH IF THE
NAM-WRF/GFS SOLUTION PANS OUT. IF THE ECMWF TURNS OUT TO BE
CORRECT...PRECIP WOULD MAINLY BE IN THE FORM OF RAIN ACROSS THE
BOARD.
LONG TERM...TUESDAY THROUGH FRIDAY
TUESDAY APPEARS TO BE THE WETTEST DAY OF THE UPCOMING WEEK...AS
INVERTED TROUGH TRACKS THROUGH THE AREA. HAVE HIT POPS HARDEST
ACROSS THE SOUTH...WITH LOWER POPS FURTHER NORTH. COULD SEE A
RAIN/SNOW MIX EARLY IN THE DAY ACROSS THE CENTRAL AND NORTHERN
ZONES...BUT SURFACE TEMPS WILL WARM SUFFICIENTLY TO CHANGE
EVERYTHING TO RAIN BY AFTERNOON. GIVEN LIGHT NATURE OF PRECIP AND
MARGINALLY COLD ATMOSPHERIC PROFILES...AM EXPECTING ONLY A
NUISANCE TYPE SNOW WITH THIS SYSTEM...WITH LITTLE OR NO ACCUMULATION.
AFTER THAT...A SLOW MODERATION IN TEMPS CAN BE EXPECTED THROUGH
THE END OF THE WEEK...WITH TEMPS GRADUALLY RISING BACK TO NEAR
NORMAL IN THE LOWER TO MIDDLE 50S BY THURSDAY AND FRIDAY.
BARNES
&&
.AVIATION...
ISSUED 1139 PM CST FRI NOV 7 2008...FOR THE 06Z TAFS
DEEP CYCLONIC FLOW AROUND THE OCCLUDED LOW WILL KEEP US IN LOW
CLOUDS...SPRINKLES/FLURRIES...AND GUSTY WEST WINDS FOR THE NEXT 24
HOURS. MVFR CONDITIONS WILL PREVAIL...WITH PIA AND BMI POSSIBLY
SEEING CIGS REACH DOWN TO IFR LATE TONIGHT. DID NOT INCLUDE A
MENTION OF THAT AS THE PROBABILITY IS TOO LOW RIGHT NOW. VIS
REDUCTION DUE TO PRECIPITATION IS MAINLY NORTH OF OUR TAF SITES
CLOSER TO THE CENTER OF THE UPPER VORTEX...WHICH IS CENTERED ON
THE WI/IL BORDER JUST SOUTH OF MONROE WIS.
FORECAST SOUNDINGS INDICATE MIXING UP TO AT LEAST 850 MB WHERE THE
35KT WINDS RESIDE. CAN NOT RULE OUT SOME GUSTS TO 30KTS TOMORROW
AFTER 16Z...BUT WILL KEEP GUSTS IN THE TAFS ONLY UP TO 25 KT FOR
NOW.
CIGS MAY INCREASE TO NEAR 3K FT DURING THE AFTERNOON...BUT NOT
MUCH HIGHER THAN THAT. WINDS SHOULD DECREASE SAT EVENING AS THE
PRES GRADIENT WEAKENS. MVFR CLOUD CIGS WILL CONTINUE SAT NIGHT.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KILX 080539
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1139 PM CST FRI NOV 7 2008
.DISCUSSION...
ISSUED 844 PM CST FRI NOV 7 2008
RAIN SHOWERS ARE STILL HOLDING TOUGH IN THE NORTHERN
CWA...ALTHOUGH WE ARE STRUGGLING FOR ANY LOCATIONS TO GET
MEASURABLE PRECIP. MOST AREAS ARE JUST GETTING TRACE AMOUNTS. WILL
KEEP CHANCE POPS GOING NORTH OF PIA TO BMI...WITH SLIGHT CHANCE POPS
DOWN TO LINCOLN AND CHAMPAIGN. WENT WITH A RAIN OR SNOW MIX THIS
EVENING INSTEAD OF JUST SNOW WORDING...DUE TO THE LINGERING RAIN
REPORTS ALL THE WAY BACK INTO EASTERN IOWA. LEFT THE AFTER
MIDNIGHT FORECAST AS ALL SNOW NORTH AND RAIN OR SNOW TOWARD
LINCOLN. MOST AREAS WILL JUST SEE TRACE AMOUNTS OF PRECIP...SO
LOWER CHC POPS SEEM REASONABLE INSTEAD OF LIKELY.
DIURNAL TEMP FALLS WILL BE MINIMAL UNDER A LOW STRATUS FRACTUS
DECK. NO CHANGES NEED TO LOWS TONIGHT. ONLY ADJUSTED THE WEATHER
GRIDS TO INCLUDE RAIN. OTHER GRIDS REMAIN REPRESENTATIVE.
TOMORROW WILL BE BLUSTERY, WITH A FEW LIGHT RAIN OR SNOW SHOWERS
IN THE NORTH. WIND CHILL VALUES WILL DIP INTO THE MID 20S IN THE
MORNING AND PROBABLY STAY BELOW FREEZING MOST OF THE DAY.
UPDATED ZONES AND GRIDS WILL BE AVAILABLE SHORTLY.
SHIMON
&&
.AVIATION...
ISSUED 1139 PM CST FRI NOV 7 2008...FOR THE 06Z TAFS
DEEP CYCLONIC FLOW AROUND THE OCCLUDED LOW WILL KEEP US IN LOW
CLOUDS...SPRINKLES/FLURRIES...AND GUSTY WEST WINDS FOR THE NEXT 24
HOURS. MVFR CONDITIONS WILL PREVAIL...WITH PIA AND BMI POSSIBLY
SEEING CIGS REACH DOWN TO IFR LATE TONIGHT. DID NOT INCLUDE A
MENTION OF THAT AS THE PROBABILITY IS TOO LOW RIGHT NOW. VIS
REDUCTION DUE TO PRECIPITATION IS MAINLY NORTH OF OUR TAF SITES
CLOSER TO THE CENTER OF THE UPPER VORTEX...WHICH IS CENTERED ON
THE WI/IL BORDER JUST SOUTH OF MONROE WIS.
FORECAST SOUNDINGS INDICATE MIXING UP TO AT LEAST 850 MB WHERE THE
35KT WINDS RESIDE. CAN NOT RULE OUT SOME GUSTS TO 30KTS TOMORROW
AFTER 16Z...BUT WILL KEEP GUSTS IN THE TAFS ONLY UP TO 25 KT FOR
NOW.
CIGS MAY INCREASE TO NEAR 3K FT DURING THE AFTERNOON...BUT NOT
MUCH HIGHER THAN THAT. WINDS SHOULD DECREASE SAT EVENING AS THE
PRES GRADIENT WEAKENS. MVFR CLOUD CIGS WILL CONTINUE SAT NIGHT.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 245 PM CST FRI NOV 7 2008
MAIN CONCERNS THIS PACKAGE IN THE SHORT TERM INCLUDE CHC OF PCPN
NEXT 24HRS AND TIMING OF NEXT SYSTEM BEGINNING OF NEXT WEEK. LONG
TERM CONCERNS INCLUDE CONTINUING PCPN CHANCES OF PCPN AND TYPE TUE
INTO TUE NIGHT. ANOTHER CONCERN IS DEGREE OF WARM UP LATER NEXT WEEK.
NAM-WRF/GFS AND ECMWF MODELS ALL SEEM TO BE VERY SIMILAR THIS
PACKAGE AND HAVE MAINTAIN CONTINUITY WITH HANDLING OF THE SYSTEM
IN IOWA TODAY. THIS GIVES HIGH DEGREE OF CONFIDENCE IN CURRENT
FORECAST NEXT 72HRS. DURING 72-84HR TIME FRAME...MODELS HAVE COME
INTO BETTER AGREEMENT WITH TIMING OF NEXT SYSTEM FOR EARLY NEXT
WEEK...MONDAY.
IN THE LONG TERM...GFS HAS COME INTO BETTER AGREEMENT WITH THE
ECMWF SOLUTION FOR THE TIMING AND TRACK OF THIS NEXT SYSTEM FROM
MONDAY THROUGH TUESDAY NIGHT. WITH ECMWF IN BETTER CONTINUITY AND
GFS COMING AROUND...FORECAST CONFIDENCE LITTLE HIGHER THAN
YESTERDAY AND WILL CONTINUE A SOLUTION CLOSE TO THE ECMWF THIS
PACKAGE.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
CUT-OFF SYSTEM MOVING ACROSS NORTHERN IOWA TODAY WILL CONTINUE TO
MOVE EAST ACROSS EXTREME NORTHERN ILLINOIS NEXT 24HRS AND THEN
LIFT NORTHEAST INTO THE GRT LKS REGION THROUGH SATURDAY. MODELS
CONTINUE TO SPREAD LIGHT PCPN ACROSS NORTHERN AREAS OF CWA TONIGHT
AND TOMORROW. THIS REMAINS REASONABLE AND WILL CONTINUE FORECAST
AS SUCH. PCPN TYPE WILL LIKELY BE LIGHT SNOW GIVEN DEGREE OF COLD
AIR ALOFT ADVECTING INTO THE REGION. AS SYSTEM LIFTS NORTHEAST
TOMORROW THERE WILL BE CONSIDERABLE WRAP AROUND THAT WILL AFFECT
THE AREA. CURRENT RADAR TRENDS INDICATE POTENTIAL FOR LIGHT PCPN
TO CONT TOMORROW SO WILL KEEP CHC OF LIGHT PCPN IN FORECAST. PCPN
TYPE COULD BECOME MIXED DEPENDING ON DEGREE OF WARM AIR NEAR THE
SFC TOMORROW. WESTERLY WINDS WILL ALSO BE ON BREEZY SIDE TOMORROW
WITH AREA REMAINING IN CYCLONIC FLOW. THEN THE CWA WILL SEE A
PERIOD OF DRY WEATHER SUNDAY AS HIGH PRSS BUILDS INTO THE REGION.
THE NEXT SYSTEM WILL DEVELOP IN THE SOUTHERN PLAINS AND SPREAD
OVER-RUNNING PCPN IN THE AREA BEGINNING MONDAY. THE RIDGE OF HIGH
PRSS COULD DELAY ONSET OF PCPN AS SFC WINDS SHOULD BE OUT OF THE
EAST SUNDAY NIGHT INTO MONDAY. BELIEVE BEST CHC OF PCPN MONDAY
WILL BE IN THE WEST AND MAINLY AFTERNOON. AS THE SYSTEM DEVELOPS
AN INVERTED TROUGH INTO THE AREA AND THE RIDGE GETS PUSHED TO THE
EAST...PCPN WILL THEN OVERSPREAD THE AREA FOR MONDAY NIGHT. MODEL
TEMP PROFILES INDICATE THAT PCPN TYPE COULD BE SNOW IN NORTH AND
RAIN IN CENTRAL AND SOUTH PARTS OF CWA.
MODEL GUIDANCE LOOKS FAIRLY GOOD WITH COLDEST MORNING BEING SUNDAY
NIGHT. CLOUD COVER AND BREEZY WINDS WILL HAVE AFFECT ON TEMPS NEXT
COUPLE OF DAYS RESULTING IN SMALL DIURNAL CHANGES.
LONG TERM...TUESDAY THROUGH FRIDAY
WITH SPLIT PATTERN TAKING CONTROL NEXT WEEK...THE SYSTEM THAT
BRINGS THE PCPN TO THE REGION FOR MON AND MONDAY NIGHT WILL WEAKEN
SOME AND SLIDE EAST INTO THE SOUTHEASTERN US. THE INVERTED TROUGH
WILL QUICKLY MOVE EAST AS WELL AS ANOTHER HIGH PRSS AREA BUILDS
INTO THE REGION. PCPN WILL CONTINUE TUE AND INTO TUE NIGHT WITH
HIGHEST CHANCES REMAINING IN SOUTHERN PARTS OF THE REGION. BY
WED/WED NIGHT THOUGH...PCPN WILL HAVE ENDED AS HIGH PRSS TAKES
CONTROL. GFS THEN WANTS TO BRING ANOTHER SYSTEM STRAIGHT NORTH
FROM THE SOUTHERN MISS VLY...BUT THIS APPEARS UNLIKELY THIS TIME
OF YEAR UNDER A SPLIT FLOW PATTERN. SO WILL FOLLOW THE DRIER ECMWF
FOR THE REMAINDER OF THE WEEK...WED NIGHT THROUGH FRIDAY.
TEMPS WILL START COOL BUT THEN BEGIN TO WARM BACK UP LATER IN THE
WEEK. CURRENT MEX GUIDANCE SHOWS THIS TREND BUT APPEARS TO BE ON
COOL SIDE AT THE MOMENT. SO TAKEN MEX AND ADJUSTED UPWARDS BY
SEVERAL DEGREES.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 080456
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1056 PM CST FRI NOV 7 2008
.DISCUSSION...
302 PM CST
MAIN FOCUS OVER THE SHORT TERM REMAINS THE SPRAWLING CYCLONE THAT
HAS TAKEN OVER MOST OF THE MIDWEST AND UPPER PLAINS AND WILL KNOCK
DOWN TEMPERATURES OVER THE NEXT FEW DAYS TO GO ALONG WITH BOUTS OF
SNOW SHOWERS.
WITH THE DRY SLOT HAVING MOVED OFF OVER MICHIGAN...THE CORE OF THE
UPPER AND SFC LOW ARE SLOWLY PROPAGATING THROUGH NORTHERN
IOWA/SOUTHERN MINNESOTA THIS AFTERNOON WITH THE MAIN SURGE OF COLD
AIR WRAPPING AROUND ON THE SOUTHERN PERIPHERY OF THE STORM
SYSTEM. THE BEST CHANCES FOR PRECIP ARE EXPECTED FROM TONIGHT INTO
SATURDAY AS THE CORE OF THE UPPER LEVEL LOW SWINGS EASTWARD ALONG
THE WISCONSIN/ILLINOIS BORDER. THIS WILL ALSO COINCIDE WITH OUR
BEST CHANCES FOR ANY ACCUMULATING SNOWFALL WHICH...IF
ANYTHING...IS EXPECTED TO BE OF RATHER MINIMAL IMPACT OUTSIDE OF
VISIBILITY ISSUES. WITH SURFACE SOIL TEMPERATURES REMAINING WELL
ABOVE FREEZING IT WILL BE DIFFICULT FOR ANY SNOW TO ACCUMULATE
EXCEPT FOR WITHIN SOME OF THE HEAVIER BURSTS OVERNIGHT. ROAD
TEMPERATURES ARE ALSO STILL WARM ENOUGH THAT MOST OF THIS SNOW
WOULD JUST MELT ANYWAYS. SO...HAVE COME UP WITH A TOTAL SNOW
ACCUMULATION OF ROUGHLY A HALF INCH OVER THE NEXT 24 HOURS
FURTHER NORTH AND WEST TOWARD THE ROCKFORD AREA WITH LESSER
AMOUNTS FURTHER SOUTH AND EAST NEAR THE LAKE. SPED UP THE
TRANSITION TO ALL SNOW QUICKER THAN PREVIOUSLY ANTICIPATED TO THIS
EVENING AS SFC TEMPS IN THE MID 30S SHOULD BE COLD ENOUGH TO
SUPPORT ALL SNOW.
TEMPERATURES WILL STRUGGLE TO WARM OVER THE NEXT FEW DAYS WITH THE
COLD LOW LEVEL AIR OVERHEAD AND THE LACK OF SUNSHINE DUE TO THE
EXTENSIVE CLOUD COVER. UNDERCUT GUIDANCE BY A FEW DEGREES THROUGH
TUESDAY AND KEPT HIGHS EITHER AROUND 40 OR LOWER. THE COLDEST DAY
OF THE FORECAST PERIOD WILL LIKELY COME ON MONDAY MORNING AS A SFC
RIDGE OF HIGH PRESSURE SETS UP FROM NORTHWEST TO SOUTHEAST ACROSS
THE CWA. IF SKIES CAN STAY CLEAR...TEMPERATURES COULD BOTTOM OUT
IN THE LOW 20S NEAR ROCKFORD.
ONTO THE BIGGEST HEADACHE IN THE FORECAST PERIOD WHICH INVOLVES
THE SOUTHERN STREAM SYSTEM ON TUESDAY. THERE STILL REMAINS QUITE A
BIT OF UNCERTAINTY THROUGH THIS PERIOD BUT THE MODELS AT LEAST ARE
STARTING TO TREND TOWARD THE PREVIOUS RUNS OF THE ECMWF`S
POSITION OF THE SFC RIDGE OVER THE DAKOTAS. THE 12Z ECMWF STILL
HAS THE RIDGE THERE...BUT IS NOT NEARLY AS BROAD AS ITS PREVIOUS
VERSIONS AND THE CURRENT RUN OF THE GFS. THE PROBLEM THAT THIS
HIGH POSES IS THAT IT WILL LIKELY ASSIST IN KEEPING THE COLD AIR
ENTRENCHED ACROSS OUR REGION AND WHEN THE PRECIP STARTS UP FROM
THE SOUTHERN LOW IT WILL THEN LIKELY FALL AS A MIXED BAG OF
SNOW...RAIN...SLEET AND WHATEVER ELSE WANTS TO COME DOWN. STARTED
TRENDING NORTHWARD WITH THE PRECIP SHIELD ACROSS NORTHERN ILLINOIS
FOR TUESDAY AND NUDGED UP POPS A BIT AS WELL. STILL DO NOT HAVE
THE CONFIDENCE IN THIS YET TO GO ALL IN WITH ALL OF THE RECENT
FLIP FLOPS AND DELAYS/SPEED UPS IN THE PRECIP/SFC LOW.
THE SILVER LINING IN ALL THIS IS THAT IT APPEARS THAT WE SHOULD BE
IN A SLIGHT WARMING TREND TOWARD THE END OF NEXT WEEK WITH
SOUTHWESTERLY WINDS.
HALBACH
&&
.AVIATION...
0600 UTC TAFS...NO BIG CHANGES PLANNED TO GOING TAFS. WRAP AROUND
RAIN/SNOW SHOWERS CONTINUE TO PIVOT AROUND LARGE CYCLONE OVER THE
WESTERN GREAT LAKES. VSBYS LARGELY STAYING VFR...THOUGH HAVE
SPORADICALLY DROPPED TO MVFR AND EVEN IFR IN SPOTS WITH THE HEAVIER
SHOWERS. HAVE ONLY TEMPO-ED FOR BRIEF PERIOD OF MVFR VSBYS EARLY
IN THE PERIOD AS MORE PRONOUNCED SHORTWAVE ROTATING AROUND THE
SYSTEM TRAVERSES THE AREA. CYCLONIC LOW LEVEL FLOW...LOW LEVEL
COLD AIR ADVECTION...AND LINGERING LOW LEVEL MOISTURE COULD BE
ENOUGH FOR SPITS OF FLURRIES AND POSSIBLY EVEN A LIGHT SNOW SHOWER
PRETTY MUCH ANYTIME THE NEXT 24-30 HOURS...BUT AVIATION IMPACT
SHOULD BE MINIMAL SO KEPT MENTION OUT OF THE TAFS BEYOND TONIGHT.
SOLID LOW END MVFR DECK EXISTS UPSTREAM OVER IOWA AND SEE NO
REASON WHY THIS WON`T ROTATE EASTWARD INTO THE AREA WITH CIGS BLO
2K FT LIKELY LATE TONIGHT THROUGH AT LEAST FIRST HALF OF
SATURDAY...WITH SOME SLIGHT IMPROVEMENT POSSIBLE IN THE AFTERNOON.
04Z SURFACE ANALYSIS SHOWS A SURFACE TROUGH ENTERING NW IL...MUCH
MORE PRONOUNCED THAN INDICATED BY MODELS. HAVE INCLUDED A BIT OF A
WIND SHIFT THAN MOS/MODELS WOULD SUGGEST BY SUNRISE. WINDS SHOULD
INCREASE SOME AND BECOME QUITE GUSTY SATURDAY IN STEEP LOW LEVEL
LAPSE RATE ENVIRONMENT ASSOCIATED WITH THE COLD AIR ADVECTION.
FORECAST SOUNDINGS SUGGEST MIXING INTO 30KT FLOW...SO GUSTS AOA
25KT LOOK LIKE A GOOD BET. WINDS/GUSTINESS MAY TEND TO SUBSIDE A
SMIDGE AFTER SUNSET SAT EVENING...THOUGH GRADIENT SHOULD REMAIN
TIGHT ENOUGH TO MAINTAIN A MODERATELY STRONG WIND INTO THE NIGHT.
IZZI
&&
.MARINE...
113 PM CST
A LOW WITH A PRESSURE WAS OVER SOUTHERN MINNESOTA THIS MORNING.
THIS LOW WILL MOVE NORTHEAST TO SOUTHERN ONTARIO BY SATURDAY
AFTERNOON. THIS LOW WILL HAVE PRESSURE LOW ENOUGH TO CREATE A
STRONG WIND OVER LAKE MICHIGAN. THERE MAY BE GALES SATURDAY. THE
WIND WILL DECREASE SLIGHTLY SUNDAY AS THEY TURN WEST. THE HIGH
WILL DEVELOP OVER NORTHERN MANITOBA WILL EXTEND SOUTH ACROSS THE
GREAT PLAINS TO OKLAHOMA BY SATURDAY EVENING.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON SATURDAY TO
MIDNIGHT SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 AM SUNDAY.
&&
$$
000
FXUS63 KILX 080244
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
844 PM CST FRI NOV 7 2008
.DISCUSSION...
ISSUED 844 PM CST FRI NOV 7 2008
RAIN SHOWERS ARE STILL HOLDING TOUGH IN THE NORTHERN
CWA...ALTHOUGH WE ARE STRUGGLING FOR ANY LOCATIONS TO GET
MEASURABLE PRECIP. MOST AREAS ARE JUST GETTING TRACE AMOUNTS. WILL
KEEP CHANCE POPS GOING NORTH OF PIA TO BMI...WITH SLIGHT CHANCE POPS
DOWN TO LINCOLN AND CHAMPAIGN. WENT WITH A RAIN OR SNOW MIX THIS
EVENING INSTEAD OF JUST SNOW WORDING...DUE TO THE LINGERING RAIN
REPORTS ALL THE WAY BACK INTO EASTERN IOWA. LEFT THE AFTER
MIDNIGHT FORECAST AS ALL SNOW NORTH AND RAIN OR SNOW TOWARD
LINCOLN. MOST AREAS WILL JUST SEE TRACE AMOUNTS OF PRECIP...SO
LOWER CHC POPS SEEM REASONABLE INSTEAD OF LIKELY.
DIURNAL TEMP FALLS WILL BE MINIMAL UNDER A LOW STRATUS FRACTUS
DECK. NO CHANGES NEED TO LOWS TONIGHT. ONLY ADJUSTED THE WEATHER
GRIDS TO INCLUDE RAIN. OTHER GRIDS REMAIN REPRESENTATIVE.
TOMORROW WILL BE BLUSTERY, WITH A FEW LIGHT RAIN OR SNOW SHOWERS
IN THE NORTH. WIND CHILL VALUES WILL DIP INTO THE MID 20S IN THE
MORNING AND PROBABLY STAY BELOW FREEZING MOST OF THE DAY.
UPDATED ZONES AND GRIDS WILL BE AVAILABLE SHORTLY.
SHIMON
&&
.AVIATION...
ISSUED 545 PM CST FRI NOV 7 2008...FOR THE 00Z TAFS
WRAP AROUND MOISTURE ASSOCIATED WITH DEEP LOW PRESSURE IN THE
WESTERN GREAT LAKES WILL KEEP MVFR CIGS IN PLACE FOR THE NEXT 24
HOURS. SATELLITE AND RADAR TRENDS INDICATE SPRINKLES OR FLURRIES
WILL BE POSSIBLE TONIGHT AT ALL TAF SITES...BUT ESPECIALLY FOR
PIA AND BMI. WILL JUST USE VCSH FOR ANY PRECIP CHANCES. NOT ENOUGH
CHANCE FOR MEASURABLE PRECIP TO INCLUDE IN PREVAILING OR A TEMPO.
VIS REDUCTIONS ARE NOT EXPECTED FROM PRECIP...SO WILL KEEP
UNRESTRICTED VIS FOR ALL SITES.
WINDS WILL REMAIN SUSTAINED AT 10-12KTS OVERNIGHT...AND BECOME
GUSTY FROM THE WEST TOMORROW. SOME GUSTS NEAR 30KTS WILL ONCE
AGAIN BE POSSIBLE. FLURRIES OR SPRINKLES WILL CONTINUE TO BE
POSSIBLE SATURDAY...AS LOW MOISTURE REMAINS IN PLACE. CIGS MAY
CLIMB SLIGHTLY FROM 2K-2.5K FT UP TO 3-3.5K FT.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 245 PM CST FRI NOV 7 2008
MAIN CONCERNS THIS PACKAGE IN THE SHORT TERM INCLUDE CHC OF PCPN
NEXT 24HRS AND TIMING OF NEXT SYSTEM BEGINNING OF NEXT WEEK. LONG
TERM CONCERNS INCLUDE CONTINUING PCPN CHANCES OF PCPN AND TYPE TUE
INTO TUE NIGHT. ANOTHER CONCERN IS DEGREE OF WARM UP LATER NEXT WEEK.
NAM-WRF/GFS AND ECMWF MODELS ALL SEEM TO BE VERY SIMILAR THIS
PACKAGE AND HAVE MAINTAIN CONTINUITY WITH HANDLING OF THE SYSTEM
IN IOWA TODAY. THIS GIVES HIGH DEGREE OF CONFIDENCE IN CURRENT
FORECAST NEXT 72HRS. DURING 72-84HR TIME FRAME...MODELS HAVE COME
INTO BETTER AGREEMENT WITH TIMING OF NEXT SYSTEM FOR EARLY NEXT
WEEK...MONDAY.
IN THE LONG TERM...GFS HAS COME INTO BETTER AGREEMENT WITH THE
ECMWF SOLUTION FOR THE TIMING AND TRACK OF THIS NEXT SYSTEM FROM
MONDAY THROUGH TUESDAY NIGHT. WITH ECMWF IN BETTER CONTINUITY AND
GFS COMING AROUND...FORECAST CONFIDENCE LITTLE HIGHER THAN
YESTERDAY AND WILL CONTINUE A SOLUTION CLOSE TO THE ECMWF THIS
PACKAGE.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
CUT-OFF SYSTEM MOVING ACROSS NORTHERN IOWA TODAY WILL CONTINUE TO
MOVE EAST ACROSS EXTREME NORTHERN ILLINOIS NEXT 24HRS AND THEN
LIFT NORTHEAST INTO THE GRT LKS REGION THROUGH SATURDAY. MODELS
CONTINUE TO SPREAD LIGHT PCPN ACROSS NORTHERN AREAS OF CWA TONIGHT
AND TOMORROW. THIS REMAINS REASONABLE AND WILL CONTINUE FORECAST
AS SUCH. PCPN TYPE WILL LIKELY BE LIGHT SNOW GIVEN DEGREE OF COLD
AIR ALOFT ADVECTING INTO THE REGION. AS SYSTEM LIFTS NORTHEAST
TOMORROW THERE WILL BE CONSIDERABLE WRAP AROUND THAT WILL AFFECT
THE AREA. CURRENT RADAR TRENDS INDICATE POTENTIAL FOR LIGHT PCPN
TO CONT TOMORROW SO WILL KEEP CHC OF LIGHT PCPN IN FORECAST. PCPN
TYPE COULD BECOME MIXED DEPENDING ON DEGREE OF WARM AIR NEAR THE
SFC TOMORROW. WESTERLY WINDS WILL ALSO BE ON BREEZY SIDE TOMORROW
WITH AREA REMAINING IN CYCLONIC FLOW. THEN THE CWA WILL SEE A
PERIOD OF DRY WEATHER SUNDAY AS HIGH PRSS BUILDS INTO THE REGION.
THE NEXT SYSTEM WILL DEVELOP IN THE SOUTHERN PLAINS AND SPREAD
OVER-RUNNING PCPN IN THE AREA BEGINNING MONDAY. THE RIDGE OF HIGH
PRSS COULD DELAY ONSET OF PCPN AS SFC WINDS SHOULD BE OUT OF THE
EAST SUNDAY NIGHT INTO MONDAY. BELIEVE BEST CHC OF PCPN MONDAY
WILL BE IN THE WEST AND MAINLY AFTERNOON. AS THE SYSTEM DEVELOPS
AN INVERTED TROUGH INTO THE AREA AND THE RIDGE GETS PUSHED TO THE
EAST...PCPN WILL THEN OVERSPREAD THE AREA FOR MONDAY NIGHT. MODEL
TEMP PROFILES INDICATE THAT PCPN TYPE COULD BE SNOW IN NORTH AND
RAIN IN CENTRAL AND SOUTH PARTS OF CWA.
MODEL GUIDANCE LOOKS FAIRLY GOOD WITH COLDEST MORNING BEING SUNDAY
NIGHT. CLOUD COVER AND BREEZY WINDS WILL HAVE AFFECT ON TEMPS NEXT
COUPLE OF DAYS RESULTING IN SMALL DIURNAL CHANGES.
LONG TERM...TUESDAY THROUGH FRIDAY
WITH SPLIT PATTERN TAKING CONTROL NEXT WEEK...THE SYSTEM THAT
BRINGS THE PCPN TO THE REGION FOR MON AND MONDAY NIGHT WILL WEAKEN
SOME AND SLIDE EAST INTO THE SOUTHEASTERN US. THE INVERTED TROUGH
WILL QUICKLY MOVE EAST AS WELL AS ANOTHER HIGH PRSS AREA BUILDS
INTO THE REGION. PCPN WILL CONTINUE TUE AND INTO TUE NIGHT WITH
HIGHEST CHANCES REMAINING IN SOUTHERN PARTS OF THE REGION. BY
WED/WED NIGHT THOUGH...PCPN WILL HAVE ENDED AS HIGH PRSS TAKES
CONTROL. GFS THEN WANTS TO BRING ANOTHER SYSTEM STRAIGHT NORTH
FROM THE SOUTHERN MISS VLY...BUT THIS APPEARS UNLIKELY THIS TIME
OF YEAR UNDER A SPLIT FLOW PATTERN. SO WILL FOLLOW THE DRIER ECMWF
FOR THE REMAINDER OF THE WEEK...WED NIGHT THROUGH FRIDAY.
TEMPS WILL START COOL BUT THEN BEGIN TO WARM BACK UP LATER IN THE
WEEK. CURRENT MEX GUIDANCE SHOWS THIS TREND BUT APPEARS TO BE ON
COOL SIDE AT THE MOMENT. SO TAKEN MEX AND ADJUSTED UPWARDS BY
SEVERAL DEGREES.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 080008
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
608 PM CST FRI NOV 7 2008
.DISCUSSION...
302 PM CST
MAIN FOCUS OVER THE SHORT TERM REMAINS THE SPRAWLING CYCLONE THAT
HAS TAKEN OVER MOST OF THE MIDWEST AND UPPER PLAINS AND WILL KNOCK
DOWN TEMPERATURES OVER THE NEXT FEW DAYS TO GO ALONG WITH BOUTS OF
SNOW SHOWERS.
WITH THE DRY SLOT HAVING MOVED OFF OVER MICHIGAN...THE CORE OF THE
UPPER AND SFC LOW ARE SLOWLY PROPAGATING THROUGH NORTHERN
IOWA/SOUTHERN MINNESOTA THIS AFTERNOON WITH THE MAIN SURGE OF COLD
AIR WRAPPING AROUND ON THE SOUTHERN PERIPHERY OF THE STORM
SYSTEM. THE BEST CHANCES FOR PRECIP ARE EXPECTED FROM TONIGHT INTO
SATURDAY AS THE CORE OF THE UPPER LEVEL LOW SWINGS EASTWARD ALONG
THE WISCONSIN/ILLINOIS BORDER. THIS WILL ALSO COINCIDE WITH OUR
BEST CHANCES FOR ANY ACCUMULATING SNOWFALL WHICH...IF
ANYTHING...IS EXPECTED TO BE OF RATHER MINIMAL IMPACT OUTSIDE OF
VISIBILITY ISSUES. WITH SURFACE SOIL TEMPERATURES REMAINING WELL
ABOVE FREEZING IT WILL BE DIFFICULT FOR ANY SNOW TO ACCUMULATE
EXCEPT FOR WITHIN SOME OF THE HEAVIER BURSTS OVERNIGHT. ROAD
TEMPERATURES ARE ALSO STILL WARM ENOUGH THAT MOST OF THIS SNOW
WOULD JUST MELT ANYWAYS. SO...HAVE COME UP WITH A TOTAL SNOW
ACCUMULATION OF ROUGHLY A HALF INCH OVER THE NEXT 24 HOURS
FURTHER NORTH AND WEST TOWARD THE ROCKFORD AREA WITH LESSER
AMOUNTS FURTHER SOUTH AND EAST NEAR THE LAKE. SPED UP THE
TRANSITION TO ALL SNOW QUICKER THAN PREVIOUSLY ANTICIPATED TO THIS
EVENING AS SFC TEMPS IN THE MID 30S SHOULD BE COLD ENOUGH TO
SUPPORT ALL SNOW.
TEMPERATURES WILL STRUGGLE TO WARM OVER THE NEXT FEW DAYS WITH THE
COLD LOW LEVEL AIR OVERHEAD AND THE LACK OF SUNSHINE DUE TO THE
EXTENSIVE CLOUD COVER. UNDERCUT GUIDANCE BY A FEW DEGREES THROUGH
TUESDAY AND KEPT HIGHS EITHER AROUND 40 OR LOWER. THE COLDEST DAY
OF THE FORECAST PERIOD WILL LIKELY COME ON MONDAY MORNING AS A SFC
RIDGE OF HIGH PRESSURE SETS UP FROM NORTHWEST TO SOUTHEAST ACROSS
THE CWA. IF SKIES CAN STAY CLEAR...TEMPERATURES COULD BOTTOM OUT
IN THE LOW 20S NEAR ROCKFORD.
ONTO THE BIGGEST HEADACHE IN THE FORECAST PERIOD WHICH INVOLVES
THE SOUTHERN STREAM SYSTEM ON TUESDAY. THERE STILL REMAINS QUITE A
BIT OF UNCERTAINTY THROUGH THIS PERIOD BUT THE MODELS AT LEAST ARE
STARTING TO TREND TOWARD THE PREVIOUS RUNS OF THE ECMWF`S
POSITION OF THE SFC RIDGE OVER THE DAKOTAS. THE 12Z ECMWF STILL
HAS THE RIDGE THERE...BUT IS NOT NEARLY AS BROAD AS ITS PREVIOUS
VERSIONS AND THE CURRENT RUN OF THE GFS. THE PROBLEM THAT THIS
HIGH POSES IS THAT IT WILL LIKELY ASSIST IN KEEPING THE COLD AIR
ENTRENCHED ACROSS OUR REGION AND WHEN THE PRECIP STARTS UP FROM
THE SOUTHERN LOW IT WILL THEN LIKELY FALL AS A MIXED BAG OF
SNOW...RAIN...SLEET AND WHATEVER ELSE WANTS TO COME DOWN. STARTED
TRENDING NORTHWARD WITH THE PRECIP SHIELD ACROSS NORTHERN ILLINOIS
FOR TUESDAY AND NUDGED UP POPS A BIT AS WELL. STILL DO NOT HAVE
THE CONFIDENCE IN THIS YET TO GO ALL IN WITH ALL OF THE RECENT
FLIP FLOPS AND DELAYS/SPEED UPS IN THE PRECIP/SFC LOW.
THE SILVER LINING IN ALL THIS IS THAT IT APPEARS THAT WE SHOULD BE
IN A SLIGHT WARMING TREND TOWARD THE END OF NEXT WEEK WITH
SOUTHWESTERLY WINDS.
HALBACH
&&
.AVIATION...
0000 UTC TAFS...LARGE CYCLONE WILL CONTINUE TO MOVE SLOWLY
EASTWARD INTO THE WESTERN GREAT LAKES TONIGHT...WITH RAIN/SNOW AND
SOME SLEET SHOWERS ROTATING AROUND THE LARGE CIRCULATION. MORE
CONCENTRATED AREA OF PRECIPITATION OVER IOWA INTO NORTHWEST
ILLINOIS SHOULD PIVOT EASTWARD AND OVERSPREAD THE TERMINALS THIS
EVENING. INITIALLY PRECIP TYPE MAY BE DICTATED BY PRECIP INTENSITY
WITH HEAVIER BURSTS LIKELY BEING MORE SN/PL...WITH LIGHT PRECIP
STARTING AS RAIN. AS DEPTH OF THE WARM LAYER DECREASES OVERNIGHT
LOOK FOR PRECIP TO TRANSITION OVER TO ALL SNOW SHOWERS. SEVERAL
LOCATIONS OVER IOWA HAVE DROPPED DOWN TO IFR IN THE HEAVIER SNOW
SHOWERS...BUT FOR NOW JUST WENT WITH A PREVAILING MVFR VSBY WITH
THE SNOW. WOULD LIKE TO WAIT TIL SNOW GETS A BIT CLOSER AND TIMING
CAN BE BETTER DEFINED BEFORE INTRODUCING IFR INTO THE TAFS.
BY SATURDAY MORNING SNOW SHOWERS WILL PROBABLY TAPER MORE TO
FLURRIES AS SHORTWAVE OVER EASTERN IOWA EVIDENT ON WATER VAPOR
IMAGERY PIVOTS OUT OF THE AREA. STEEP LOW LEVEL LAPSE
RATES...CONTINUED CYCLONIC FLOW AND COLD AIR ADVECTION COULD BE
ENOUGH TO CONTINUE TO SQUEEZE OUT SOME FLURRIES OR VERY LIGHT SNOW
SHOWERS THROUGH THE DAY SATURDAY...BUT IMPACT ON AVIATION SHOULD
BE MINIMAL AND HAVE OPTED TO KEEP OUT OF THE TAFS ATTM.
FINALLY...WINDS SHOULD SLOWLY VEER AROUND TO MORE WESTERLY
EVENTUALLY WEST-NORTHWESTERLY OVER THE NEXT 24/30 HOURS. COULD SEE
A FEW GUSTS UP TO 20KT THROUGH THE NIGHT...PARTICULARLY WITH THE
HEAVIER SHOWERS...THOUGH SHOULD SEE MORE PREVAILING GUSTINESS
DURING THE DAY SATURDAY AS SOME INSOLATION SHOULD OCCUR THROUGH
THE OVC DECK.
IZZI
&&
.MARINE...
113 PM CST
A LOW WITH A PRESSURE WAS OVER SOUTHERN MINNESOTA THIS MORNING.
THIS LOW WILL MOVE NORTHEAST TO SOUTHERN ONTARIO BY SATURDAY
AFTERNOON. THIS LOW WILL HAVE PRESSURE LOW ENOUGH TO CREATE A
STRONG WIND OVER LAKE MICHIGAN. THERE MAY BE GALES SATURDAY. THE
WIND WILL DECREASE SLIGHTLY SUNDAY AS THEY TURN WEST. THE HIGH
WILL DEVELOP OVER NORTHERN MANITOBA WILL EXTEND SOUTH ACROSS THE
GREAT PLAINS TO OKLAHOMA BY SATURDAY EVENING.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON SATURDAY TO
MIDNIGHT SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 AM SUNDAY.
&&
$$
000
FXUS63 KILX 072346
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
546 PM CST FRI NOV 7 2008
.DISCUSSION...
ISSUED 245 PM CST FRI NOV 7 2008
MAIN CONCERNS THIS PACKAGE IN THE SHORT TERM INCLUDE CHC OF PCPN
NEXT 24HRS AND TIMING OF NEXT SYSTEM BEGINNING OF NEXT WEEK. LONG
TERM CONCERNS INCLUDE CONTINUING PCPN CHANCES OF PCPN AND TYPE TUE
INTO TUE NIGHT. ANOTHER CONCERN IS DEGREE OF WARM UP LATER NEXT WEEK.
NAM-WRF/GFS AND ECMWF MODELS ALL SEEM TO BE VERY SIMILAR THIS
PACKAGE AND HAVE MAINTAIN CONTINUITY WITH HANDLING OF THE SYSTEM
IN IOWA TODAY. THIS GIVES HIGH DEGREE OF CONFIDENCE IN CURRENT
FORECAST NEXT 72HRS. DURING 72-84HR TIME FRAME...MODELS HAVE COME
INTO BETTER AGREEMENT WITH TIMING OF NEXT SYSTEM FOR EARLY NEXT
WEEK...MONDAY.
IN THE LONG TERM...GFS HAS COME INTO BETTER AGREEMENT WITH THE
ECMWF SOLUTION FOR THE TIMING AND TRACK OF THIS NEXT SYSTEM FROM
MONDAY THROUGH TUESDAY NIGHT. WITH ECMWF IN BETTER CONTINUITY AND
GFS COMING AROUND...FORECAST CONFIDENCE LITTLE HIGHER THAN
YESTERDAY AND WILL CONTINUE A SOLUTION CLOSE TO THE ECMWF THIS
PACKAGE.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
CUT-OFF SYSTEM MOVING ACROSS NORTHERN IOWA TODAY WILL CONTINUE TO
MOVE EAST ACROSS EXTREME NORTHERN ILLINOIS NEXT 24HRS AND THEN
LIFT NORTHEAST INTO THE GRT LKS REGION THROUGH SATURDAY. MODELS
CONTINUE TO SPREAD LIGHT PCPN ACROSS NORTHERN AREAS OF CWA TONIGHT
AND TOMORROW. THIS REMAINS REASONABLE AND WILL CONTINUE FORECAST
AS SUCH. PCPN TYPE WILL LIKELY BE LIGHT SNOW GIVEN DEGREE OF COLD
AIR ALOFT ADVECTING INTO THE REGION. AS SYSTEM LIFTS NORTHEAST
TOMORROW THERE WILL BE CONSIDERABLE WRAP AROUND THAT WILL AFFECT
THE AREA. CURRENT RADAR TRENDS INDICATE POTENTIAL FOR LIGHT PCPN
TO CONT TOMORROW SO WILL KEEP CHC OF LIGHT PCPN IN FORECAST. PCPN
TYPE COULD BECOME MIXED DEPENDING ON DEGREE OF WARM AIR NEAR THE
SFC TOMORROW. WESTERLY WINDS WILL ALSO BE ON BREEZY SIDE TOMORROW
WITH AREA REMAINING IN CYCLONIC FLOW. THEN THE CWA WILL SEE A
PERIOD OF DRY WEATHER SUNDAY AS HIGH PRSS BUILDS INTO THE REGION.
THE NEXT SYSTEM WILL DEVELOP IN THE SOUTHERN PLAINS AND SPREAD
OVER-RUNNING PCPN IN THE AREA BEGINNING MONDAY. THE RIDGE OF HIGH
PRSS COULD DELAY ONSET OF PCPN AS SFC WINDS SHOULD BE OUT OF THE
EAST SUNDAY NIGHT INTO MONDAY. BELIEVE BEST CHC OF PCPN MONDAY
WILL BE IN THE WEST AND MAINLY AFTERNOON. AS THE SYSTEM DEVELOPS
AN INVERTED TROUGH INTO THE AREA AND THE RIDGE GETS PUSHED TO THE
EAST...PCPN WILL THEN OVERSPREAD THE AREA FOR MONDAY NIGHT. MODEL
TEMP PROFILES INDICATE THAT PCPN TYPE COULD BE SNOW IN NORTH AND
RAIN IN CENTRAL AND SOUTH PARTS OF CWA.
MODEL GUIDANCE LOOKS FAIRLY GOOD WITH COLDEST MORNING BEING SUNDAY
NIGHT. CLOUD COVER AND BREEZY WINDS WILL HAVE AFFECT ON TEMPS NEXT
COUPLE OF DAYS RESULTING IN SMALL DIURNAL CHANGES.
LONG TERM...TUESDAY THROUGH FRIDAY
WITH SPLIT PATTERN TAKING CONTROL NEXT WEEK...THE SYSTEM THAT
BRINGS THE PCPN TO THE REGION FOR MON AND MONDAY NIGHT WILL WEAKEN
SOME AND SLIDE EAST INTO THE SOUTHEASTERN US. THE INVERTED TROUGH
WILL QUICKLY MOVE EAST AS WELL AS ANOTHER HIGH PRSS AREA BUILDS
INTO THE REGION. PCPN WILL CONTINUE TUE AND INTO TUE NIGHT WITH
HIGHEST CHANCES REMAINING IN SOUTHERN PARTS OF THE REGION. BY
WED/WED NIGHT THOUGH...PCPN WILL HAVE ENDED AS HIGH PRSS TAKES
CONTROL. GFS THEN WANTS TO BRING ANOTHER SYSTEM STRAIGHT NORTH
FROM THE SOUTHERN MISS VLY...BUT THIS APPEARS UNLIKELY THIS TIME
OF YEAR UNDER A SPLIT FLOW PATTERN. SO WILL FOLLOW THE DRIER ECMWF
FOR THE REMAINDER OF THE WEEK...WED NIGHT THROUGH FRIDAY.
TEMPS WILL START COOL BUT THEN BEGIN TO WARM BACK UP LATER IN THE
WEEK. CURRENT MEX GUIDANCE SHOWS THIS TREND BUT APPEARS TO BE ON
COOL SIDE AT THE MOMENT. SO TAKEN MEX AND ADJUSTED UPWARDS BY
SEVERAL DEGREES.
AUTEN
&&
.AVIATION...
ISSUED 545 PM CST FRI NOV 7 2008...FOR THE 00Z TAFS
WRAP AROUND MOISTURE ASSOCIATED WITH DEEP LOW PRESSURE IN THE
WESTERN GREAT LAKES WILL KEEP MVFR CIGS IN PLACE FOR THE NEXT 24
HOURS. SATELLITE AND RADAR TRENDS INDICATE SPRINKLES OR FLURRIES
WILL BE POSSIBLE TONIGHT AT ALL TAF SITES...BUT ESPECIALLY FOR
PIA AND BMI. WILL JUST USE VCSH FOR ANY PRECIP CHANCES. NOT ENOUGH
CHANCE FOR MEASURABLE PRECIP TO INCLUDE IN PREVAILING OR A TEMPO.
VIS REDUCTIONS ARE NOT EXPECTED FROM PRECIP...SO WILL KEEP
UNRESTRICTED VIS FOR ALL SITES.
WINDS WILL REMAIN SUSTAINED AT 10-12KTS OVERNIGHT...AND BECOME
GUSTY FROM THE WEST TOMORROW. SOME GUSTS NEAR 30KTS WILL ONCE
AGAIN BE POSSIBLE. FLURRIES OR SPRINKLES WILL CONTINUE TO BE
POSSIBLE SATURDAY...AS LOW MOISTURE REMAINS IN PLACE. CIGS MAY
CLIMB SLIGHTLY FROM 2K-2.5K FT UP TO 3-3.5K FT.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 072102
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
302 PM CST FRI NOV 7 2008
.DISCUSSION...
302 PM CST
MAIN FOCUS OVER THE SHORT TERM REMAINS THE SPRAWLING CYCLONE THAT
HAS TAKEN OVER MOST OF THE MIDWEST AND UPPER PLAINS AND WILL KNOCK
DOWN TEMPERATURES OVER THE NEXT FEW DAYS TO GO ALONG WITH BOUTS OF
SNOW SHOWERS.
WITH THE DRY SLOT HAVING MOVED OFF OVER MICHIGAN...THE CORE OF THE
UPPER AND SFC LOW ARE SLOWLY PROPAGATING THROUGH NORTHERN
IOWA/SOUTHERN MINNESOTA THIS AFTERNOON WITH THE MAIN SURGE OF COLD
AIR WRAPPING AROUND ON THE SOUTHERN PERIPHERY OF THE STORM
SYSTEM. THE BEST CHANCES FOR PRECIP ARE EXPECTED FROM TONIGHT INTO
SATURDAY AS THE CORE OF THE UPPER LEVEL LOW SWINGS EASTWARD ALONG
THE WISCONSIN/ILLINOIS BORDER. THIS WILL ALSO COINCIDE WITH OUR
BEST CHANCES FOR ANY ACCUMULATING SNOWFALL WHICH...IF
ANYTHING...IS EXPECTED TO BE OF RATHER MINIMAL IMPACT OUTSIDE OF
VISIBILITY ISSUES. WITH SURFACE SOIL TEMPERATURES REMAINING WELL
ABOVE FREEZING IT WILL BE DIFFICULT FOR ANY SNOW TO ACCUMULATE
EXCEPT FOR WITHIN SOME OF THE HEAVIER BURSTS OVERNIGHT. ROAD
TEMPERATURES ARE ALSO STILL WARM ENOUGH THAT MOST OF THIS SNOW
WOULD JUST MELT ANYWAYS. SO...HAVE COME UP WITH A TOTAL SNOW
ACCUMULATION OF ROUGHLY A HALF INCH OVER THE NEXT 24 HOURS
FURTHER NORTH AND WEST TOWARD THE ROCKFORD AREA WITH LESSER
AMOUNTS FURTHER SOUTH AND EAST NEAR THE LAKE. SPED UP THE
TRANSITION TO ALL SNOW QUICKER THAN PREVIOUSLY ANTICIPATED TO THIS
EVENING AS SFC TEMPS IN THE MID 30S SHOULD BE COLD ENOUGH TO
SUPPORT ALL SNOW.
TEMPERATURES WILL STRUGGLE TO WARM OVER THE NEXT FEW DAYS WITH THE
COLD LOW LEVEL AIR OVERHEAD AND THE LACK OF SUNSHINE DUE TO THE
EXTENSIVE CLOUD COVER. UNDERCUT GUIDANCE BY A FEW DEGREES THROUGH
TUESDAY AND KEPT HIGHS EITHER AROUND 40 OR LOWER. THE COLDEST DAY
OF THE FORECAST PERIOD WILL LIKELY COME ON MONDAY MORNING AS A SFC
RIDGE OF HIGH PRESSURE SETS UP FROM NORTHWEST TO SOUTHEAST ACROSS
THE CWA. IF SKIES CAN STAY CLEAR...TEMPERATURES COULD BOTTOM OUT
IN THE LOW 20S NEAR ROCKFORD.
ONTO THE BIGGEST HEADACHE IN THE FORECAST PERIOD WHICH INVOLVES
THE SOUTHERN STREAM SYSTEM ON TUESDAY. THERE STILL REMAINS QUITE A
BIT OF UNCERTAINTY THROUGH THIS PERIOD BUT THE MODELS AT LEAST ARE
STARTING TO TREND TOWARD THE PREVIOUS RUNS OF THE ECMWF`S
POSITION OF THE SFC RIDGE OVER THE DAKOTAS. THE 12Z ECMWF STILL
HAS THE RIDGE THERE...BUT IS NOT NEARLY AS BROAD AS ITS PREVIOUS
VERSIONS AND THE CURRENT RUN OF THE GFS. THE PROBLEM THAT THIS
HIGH POSES IS THAT IT WILL LIKELY ASSIST IN KEEPING THE COLD AIR
ENTRENCHED ACROSS OUR REGION AND WHEN THE PRECIP STARTS UP FROM
THE SOUTHERN LOW IT WILL THEN LIKELY FALL AS A MIXED BAG OF
SNOW...RAIN...SLEET AND WHATEVER ELSE WANTS TO COME DOWN. STARTED
TRENDING NORTHWARD WITH THE PRECIP SHIELD ACROSS NORTHERN ILLINOIS
FOR TUESDAY AND NUDGED UP POPS A BIT AS WELL. STILL DO NOT HAVE
THE CONFIDENCE IN THIS YET TO GO ALL IN WITH ALL OF THE RECENT
FLIP FLOPS AND DELAYS/SPEED UPS IN THE PRECIP/SFC LOW.
THE SILVER LINING IN ALL THIS IS THAT IT APPEARS THAT WE SHOULD BE
IN A SLIGHT WARMING TREND TOWARD THE END OF NEXT WEEK WITH
SOUTHWESTERLY WINDS.
HALBACH
&&
.AVIATION...
1800 UTC TAFS...SHOWERS WILL MOVE INTO NORTHERN ILLINOIS AND
NORTHWEST INDIANA THIS AFTERNOON. THE LOW WAS OVER SOUTHERN
MINNESOTA AT 19 UTC. WE EXPECT THIS LOW TO SLOWLY MOVE NORTHEAST
TO SOUTHERN ONTARIO BY 12 UTC SATURDAY. THE WRAP AROUND LOW
CEILINGS WILL MOVE INTO NORTHERN ILLINOIS LATE AFTERNOON AND
EVENING. WE WILL FORECAST MVFR CEILINGS AFTER 20 UTC. THERE IS
ENOUGH LIFT WITH THIS LOW AND ITS UPPER AIR SUPPORT TO PRODUCE
BANDS OF SHOWERS. THE PROFILER DATA SHOWS A 50 KNOT 700 MB WIND
MAXIMUM MOVING NORTHEAST INTO CENTRAL ILLINOIS FROM MISSOURI.
THIS JET SHOWS THE STRENGTH OF THE UPPER AIR LOW. THE ACARS
SOUNDING AT ORD SHOWS A FREEZING LEVEL AT 9000 FT AT 15 UTC. THE
AIR MASS THAT WILL MOVE INTO NORTHEAST ILLINOIS AND NORTHWEST
INDIANA WILL HAVE A FREEZING LEVEL OF OF 2300 FEET. WE WILL FORECAST
RAIN MIXED WITH SNOW LATE THIS AFTERNOON AND EVENING. WE WILL
FORECAST RAIN MIXED WITH SNOW FORECAST FOR TONIGHT BUT WE MAY
UPDATE LATER TO ALL SNOW. THIS WILL DEPEND ON HOW FAST THE COLD
AIR MOVES INTO NORTHERN ILLINOIS.
&&
.MARINE...
113 PM CST
A LOW WITH A PRESSURE WAS OVER SOUTHERN MINNESOTA THIS MORNING.
THIS LOW WILL MOVE NORTHEAST TO SOUTHERN ONTARIO BY SATURDAY
AFTERNOON. THIS LOW WILL HAVE PRESSURE LOW ENOUGH TO CREATE A
STRONG WIND OVER LAKE MICHIGAN. THERE MAY BE GALES SATURDAY. THE
WIND WILL DECREASE SLIGHTLY SUNDAY AS THEY TURN WEST. THE HIGH
WILL DEVELOP OVER NORTHERN MANITOBA WILL EXTEND SOUTH ACROSS THE
GREAT PLAINS TO OKLAHOMA BY SATURDAY EVENING.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 PM FRIDAY TO 6 AM SUNDAY.
GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM SATURDAY TO 3 AM SUNDAY.
&&
$$
000
FXUS63 KILX 072045
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
245 PM CST FRI NOV 7 2008
.DISCUSSION...
ISSUED 245 PM CST FRI NOV 7 2008
MAIN CONCERNS THIS PACKAGE IN THE SHORT TERM INCLUDE CHC OF PCPN
NEXT 24HRS AND TIMING OF NEXT SYSTEM BEGINNING OF NEXT WEEK. LONG
TERM CONCERNS INCLUDE CONTINUING PCPN CHANCES OF PCPN AND TYPE TUE
INTO TUE NIGHT. ANOTHER CONCERN IS DEGREE OF WARM UP LATER NEXT WEEK.
NAM-WRF/GFS AND ECMWF MODELS ALL SEEM TO BE VERY SIMILAR THIS
PACKAGE AND HAVE MAINTAIN CONTINUITY WITH HANDLING OF THE SYSTEM
IN IOWA TODAY. THIS GIVES HIGH DEGREE OF CONFIDENCE IN CURRENT
FORECAST NEXT 72HRS. DURING 72-84HR TIME FRAME...MODELS HAVE COME
INTO BETTER AGREEMENT WITH TIMING OF NEXT SYSTEM FOR EARLY NEXT
WEEK...MONDAY.
IN THE LONG TERM...GFS HAS COME INTO BETTER AGREEMENT WITH THE
ECMWF SOLUTION FOR THE TIMING AND TRACK OF THIS NEXT SYSTEM FROM
MONDAY THROUGH TUESDAY NIGHT. WITH ECMWF IN BETTER CONTINUITY AND
GFS COMING AROUND...FORECAST CONFIDENCE LITTLE HIGHER THAN
YESTERDAY AND WILL CONTINUE A SOLUTION CLOSE TO THE ECMWF THIS
PACKAGE.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
CUT-OFF SYSTEM MOVING ACROSS NORTHERN IOWA TODAY WILL CONTINUE TO
MOVE EAST ACROSS EXTREME NORTHERN ILLINOIS NEXT 24HRS AND THEN
LIFT NORTHEAST INTO THE GRT LKS REGION THROUGH SATURDAY. MODELS
CONTINUE TO SPREAD LIGHT PCPN ACROSS NORTHERN AREAS OF CWA TONIGHT
AND TOMORROW. THIS REMAINS REASONABLE AND WILL CONTINUE FORECAST
AS SUCH. PCPN TYPE WILL LIKELY BE LIGHT SNOW GIVEN DEGREE OF COLD
AIR ALOFT ADVECTING INTO THE REGION. AS SYSTEM LIFTS NORTHEAST
TOMORROW THERE WILL BE CONSIDERABLE WRAP AROUND THAT WILL AFFECT
THE AREA. CURRENT RADAR TRENDS INDICATE POTENTIAL FOR LIGHT PCPN
TO CONT TOMORROW SO WILL KEEP CHC OF LIGHT PCPN IN FORECAST. PCPN
TYPE COULD BECOME MIXED DEPENDING ON DEGREE OF WARM AIR NEAR THE
SFC TOMORROW. WESTERLY WINDS WILL ALSO BE ON BREEZY SIDE TOMORROW
WITH AREA REMAINING IN CYCLONIC FLOW. THEN THE CWA WILL SEE A
PERIOD OF DRY WEATHER SUNDAY AS HIGH PRSS BUILDS INTO THE REGION.
THE NEXT SYSTEM WILL DEVELOP IN THE SOUTHERN PLAINS AND SPREAD
OVER-RUNNING PCPN IN THE AREA BEGINNING MONDAY. THE RIDGE OF HIGH
PRSS COULD DELAY ONSET OF PCPN AS SFC WINDS SHOULD BE OUT OF THE
EAST SUNDAY NIGHT INTO MONDAY. BELIEVE BEST CHC OF PCPN MONDAY
WILL BE IN THE WEST AND MAINLY AFTERNOON. AS THE SYSTEM DEVELOPS
AN INVERTED TROUGH INTO THE AREA AND THE RIDGE GETS PUSHED TO THE
EAST...PCPN WILL THEN OVERSPREAD THE AREA FOR MONDAY NIGHT. MODEL
TEMP PROFILES INDICATE THAT PCPN TYPE COULD BE SNOW IN NORTH AND
RAIN IN CENTRAL AND SOUTH PARTS OF CWA.
MODEL GUIDANCE LOOKS FAIRLY GOOD WITH COLDEST MORNING BEING SUNDAY
NIGHT. CLOUD COVER AND BREEZY WINDS WILL HAVE AFFECT ON TEMPS NEXT
COUPLE OF DAYS RESULTING IN SMALL DIURNAL CHANGES.
LONG TERM...TUESDAY THROUGH FRIDAY
WITH SPLIT PATTERN TAKING CONTROL NEXT WEEK...THE SYSTEM THAT
BRINGS THE PCPN TO THE REGION FOR MON AND MONDAY NIGHT WILL WEAKEN
SOME AND SLIDE EAST INTO THE SOUTHEASTERN US. THE INVERTED TROUGH
WILL QUICKLY MOVE EAST AS WELL AS ANOTHER HIGH PRSS AREA BUILDS
INTO THE REGION. PCPN WILL CONTINUE TUE AND INTO TUE NIGHT WITH
HIGHEST CHANCES REMAINING IN SOUTHERN PARTS OF THE REGION. BY
WED/WED NIGHT THOUGH...PCPN WILL HAVE ENDED AS HIGH PRSS TAKES
CONTROL. GFS THEN WANTS TO BRING ANOTHER SYSTEM STRAIGHT NORTH
FROM THE SOUTHERN MISS VLY...BUT THIS APPEARS UNLIKELY THIS TIME
OF YEAR UNDER A SPLIT FLOW PATTERN. SO WILL FOLLOW THE DRIER ECMWF
FOR THE REMAINDER OF THE WEEK...WED NIGHT THROUGH FRIDAY.
TEMPS WILL START COOL BUT THEN BEGIN TO WARM BACK UP LATER IN THE
WEEK. CURRENT MEX GUIDANCE SHOWS THIS TREND BUT APPEARS TO BE ON
COOL SIDE AT THE MOMENT. SO TAKEN MEX AND ADJUSTED UPWARDS BY
SEVERAL DEGREES.
AUTEN
&&
.AVIATION...
ISSUED 1139 AM CST FRI NOV 7 2008
LOW PRESSURE ON APPROACH...AND CYCLONIC FLOW WILL CLOUD UP ILX
TERMINALS THROUGH THE 24HRS. CEILINGS WILL WAIVER BTWN MVFR AND
VFR...RIGHT AT OR AROUND 3KFT. WINDS WILL BE PRESSURE GRADIENT
DRIVEN AND SHOULD STAY UP OVERNIGHT...AND THROUGH THE
MORNING...THOUGH POSSIBLY NOT AS GUSTY AS CURRENT CONDITIONS.
PRECIP WILL BE SCATTERED...AND WILL REMAIN VCSH FOR THE
AFTERNOON... UNTIL IMMINENT TO ANY ONE TERMINAL.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 072009
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
209 PM CST FRI NOV 7 2008
.DISCUSSION...
251 AM CST
POST FRONTAL CLEAR SLOT SHUD LAST THRU SUNRISE BUT SHUD SLOWLY ERODE
THRU THE MORNING AS THE BACKWASH UPR LOW WRAPAROUND WORKS EAST
ACROSS NRN IL. EMBEDDED IN THIS COMMA HEAD ARE MINUS 850 TEMPS
WRINGING OUT RESIDUAL MSTR INTO LIGHT RAIN AND EVEN SNOW SHOWERS
ACROSS IOWA. DAYTIME SENSIBLE HEATING SHUD COUNTERACT THE FIRST
WAVES OF CAA IN THE MRNG...BUT WILL LIKELY SUCCUMB TO FALLING MID TO
LATE AFTN TEMPS AS CLOUD COVER THICKENS. CONSIDERING BOUNDARY LAYER
WARMING...WUD NOT BOTHER WITH SNOW FOR MOST OF AREA UNTIL AFTER DARK
THIS EVENING. WILL PROBLY LEAVE IN RAIN OR SNOW IN NORTH CENTRAL IL
FOR THIS AFTN BUT NOT TRANSITION TO SNOW COMPLETELY UNTIL TONIGHT.
BOUNDARY LAYERED WET BULB ZERO CLOSES IN ACROSS NRN IL LATE TONIGHT
INTO SAT MRNG ON MODELS...BUT SEEMS TO BE CURRENTLY TRANSITIONING TO
SNOW AHEAD OF PROPOSED WBZ IN NWRN IOWA ALREADY. MOST MODELS
OUTPUTTING A TENTH TO HALF INCH OF SNOW NORTH OF I-88 BY SAT MRNG
BUT WITH 4 INCH SOIL TEMPS STILL AROUND 50...EXPECT THE LOWER VALUE
AT BEST...AND THIS ONLY TEMPORARILY IN A HEAVY SNOW BURST. EXPECTING
LOW TEMPS SAT MRNG STILL HOVERING AT OR ABOVE FREEZING ANYWAY.
UPR LOW TRACKING SLOWLY OFF TO NRN LOWER MICHIGAN SATURDAY AND
VEERING WINDS FROM SW TO WEST WHILE BEARING FURTHER CAA WITH 850
TEMPS DROPPING ANOTHER COUPLE OF DEGREES. RAIN AND SNOW MIX SHUD
TRANSITION TO FLURRIES SAT EVENING WITH THIS INCREASED CHILLING.
UPPER LOW PROGRESSION STILL REMAINS SLOW ON SUNDAY WITH PROGRESS
ACROSS LAKE HURON THRU SUNDAY MRNG...THEN INTO SW QUEBEC SUNDAY
NIGHT. THIS MOVE SHUD BE FAR ENUF TO END PCPN AND PERMIT SOME
CLEARING TO MOVE IN FROM THE WEST.
CLEARING IS SHORT LIVED HOWEVER AS A SYSTEM DEEPENING NEAR THE TX
PANHANDLE SPEWS WAA CI AND AC NWD INTO THE MID MS VLY MONDAY
AFTERNOON. MODELS HAVE BEEN YO-YO-ING THIS SYSTEM IN TIME AND
GEOGRAPHY THE LAST COUPLE OF DAYS. TONIGHT IS NO EXCEPTION WITH GFS
TAKING A CLOSED SFC LOW ACROSS ST. LOUIS TUES MRNG AND ECMWF WORKING
A RATHER LOOSE INVERTED TROF ACROSS THE LOWER MS VLY NEAR THAT TIME.
THUS HAVE CHANGED THE EXTENDED VERY LITTLE...KEEPING PCPN TO A
MINIMUM ACROSS THE SOUTH PORTION OF CWA.
RLB
&&
.AVIATION...
1800 UTC TAFS...SHOWERS WILL MOVE INTO NORTHERN ILLINOIS AND
NORTHWEST INDIANA THIS AFTERNOON. THE LOW WAS OVER SOUTHERN
MINNESOTA AT 19 UTC. WE EXPECT THIS LOW TO SLOWLY MOVE NORTHEAST
TO SOUTHERN ONTARIO BY 12 UTC SATURDAY. THE WRAP AROUND LOW
CEILINGS WILL MOVE INTO NORTHERN ILLINOIS LATE AFTERNOON AND
EVENING. WE WILL FORECAST MVFR CEILINGS AFTER 20 UTC. THERE IS
ENOUGH LIFT WITH THIS LOW AND ITS UPPER AIR SUPPORT TO PRODUCE
BANDS OF SHOWERS. THE PROFILER DATA SHOWS A 50 KNOT 700 MB WIND
MAXIMUM MOVING NORTHEAST INTO CENTRAL ILLINOIS FROM MISSOURI.
THIS JET SHOWS THE STRENGTH OF THE UPPER AIR LOW. THE ACARS
SOUNDING AT ORD SHOWS A FREEZING LEVEL AT 9000 FT AT 15 UTC. THE
AIR MASS THAT WILL MOVE INTO NORTHEAST ILLINOIS AND NORTHWEST
INDIANA WILL HAVE A FREEZING LEVEL OF OF 2300 FEET. WE WILL FORECAST
RAIN MIXED WITH SNOW LATE THIS AFTERNOON AND EVENING. WE WILL
FORECAST RAIN MIXED WITH SNOW FORECAST FOR TONIGHT BUT WE MAY
UPDATE LATER TO ALL SNOW. THIS WILL DEPEND ON HOW FAST THE COLD
AIR MOVES INTO NORTHERN ILLINOIS.
&&
.MARINE...
113 PM CST
A LOW WITH A PRESSURE WAS OVER SOUTHERN MINNESOTA THIS MORNING.
THIS LOW WILL MOVE NORTHEAST TO SOUTHERN ONTARIO BY SATURDAY
AFTERNOON. THIS LOW WILL HAVE PRESSURE LOW ENOUGH TO CREATE STRONG
WIND OVER LAKE MICHIGAN. THERE MAY BE GALES SATURDAY. THE WIND
WILL DECREASE SLIGHTLY SUNDAY AS THEY TURN WEST. THE HIGH WILL
DEVELOP OVER NORTHERN MANITOBA WILL EXTEND SOUTH ACROSS THE GREAT
PLAINS TO OKLAHOMA BY SATURDAY EVENING.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 PM FRIDAY TO 6 AM SUNDAY.
GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777
-LMZ779- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON SATURDAY
TO MIDNIGHT SUNDAY.
&&
$$
000
FXUS63 KILX 071746
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1146 AM CST FRI NOV 7 2008
.DISCUSSION...
ISSUED 1022 AM CST FRI NOV 7 2008
LOW PRESSURE SYSTEM APPROACHING FROM THE WEST THIS MORNING AFTER
YESTERDAYS COLD FRONT. CLOUDS MOVING INTO THE REGION WITH THE
LOW...AND SLOWLY COVERING UP A SUNNY START TO THE MORNING. CLOUDS
A BIT SLOWER THAN PREVIOUS MODEL RUNS AND HAVE ADJUSTED THE GRIDS
ACCORDINGLY. OTHER THAN THAT...FORECAST IS ON TRACK AND DOING
WELL. SLIGHT CHANCE POPS MORE THAN ENOUGH FOR THE RANDOM SPRINKLE
THAT IS MOVING INTO THE FA ON RADAR IN THE WEST. NOT ANTICIPATING
A MAJOR CHANGE TO THE FORECAST EXCEPT TO POSSIBLY ELIMINATE
MORNING WORDING AROUND MID DAY.
&&
.AVIATION...
ISSUED 1139 AM CST FRI NOV 7 2008
LOW PRESSURE ON APPROACH...AND CYCLONIC FLOW WILL CLOUD UP ILX
TERMINALS THROUGH THE 24HRS. CEILINGS WILL WAIVER BTWN MVFR AND
VFR...RIGHT AT OR AROUND 3KFT. WINDS WILL BE PRESSURE GRADIENT
DRIVEN AND SHOULD STAY UP OVERNIGHT...AND THROUGH THE
MORNING...THOUGH POSSIBLY NOT AS GUSTY AS CURRENT CONDITIONS.
PRECIP WILL BE SCATTERED...AND WILL REMAIN VCSH FOR THE
AFTERNOON... UNTIL IMMINENT TO ANY ONE TERMINAL.
HJS
&&
.PREV DISCUSSION...
ISSUED 330 AM CST FRI NOV 7 2008
BIG CHANGE IN AIRMASS AS MUCH COOLER AIR FILTERING INTO IL THROUGH
THIS WEEKEND. LARGE/STRONG UPPER LEVEL LOW PRESSURE OVER SW MN TO
DOMINATE IL/S WEATHER INTO THIS WEEKEND AS IT DRIFTS SLOWLY EAST
ACROSS THE GREAT LAKES AND SE CANADA THIS WEEKEND. FORECAST
CONCERN IS HOW FAR SOUTH PRECIPITATION GETS AND PRECIPITATION TYPE.
THEN LOOKING AS WX SYSTEM OFF THE WEST COAST MOVING INTO THE
SOUTHERN PLAINS EARLY NEXT WEEK AND EJECTING NE TOWARD THE OHIO
VALLEY TUE. 00Z GFS CONTINUES TO BE FURTHER SOUTH WITH QPF THAN
NAM MODEL INTO THIS WEEKEND AND USED A BLEND WHICH IS SIMILAR TO
ECMWF MODEL.
09Z/3 AM SURFACE MAP SHOWS STRONG 997 MB LOW PRESSURE OVER SW MN
AND VERY STRONG 534 DM 500 MB LOW IN SW MN SO STRONG STORM SYSTEM
THAT HAS PRODUCED BLIZZARD CONDITIONS OVER PARTS OF THE DAKOTAS
HAS BECOME VERTICALLY STACKED. STRONG COLD FRONT HAS MOVED EAST OF
IL INTO EASTERN INDIANA AND CENTRAL KY. LARGE DRY SLOT WITH CLEAR
SKIES OVER IL EARLY THIS MORNING AS AS FAR NORTH AS EASTERN WI AND
LAKE MI. COOLER TEMPS WERE IN THE LOW TO MID 40S WITH GALESBURG
DOWN TO 37F. SW WINDS HAVE TEMPORARILY SUBSIDE TO LESS THAN 10 MPH.
LARGE AREA OF WRAP AROUND LOW CLOUDS WERE SPREADING SE ACROSS IA
AND NW MO AND NEARING THE IL/IA BORDER.
SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
MODELS SIMILAR IN DRIFTING STRONG VERTICALLY STACKED LOW PRESSURE
SYSTEM SLOWLY EASTWARD ACROSS THE MN/IA BORDER TODAY AND OVER
SOUTHERN WI TONIGHT AND INTO CENTRAL LAKE MI BY SAT MORNING.
LOW CLOUDS TO SPREAD SE TOWARD GALESBURG BY 12Z TO DEC/CMI BY NOON
AND INTO SE IL DURING THIS AFTERNOON. STRONG VORT MAX MOVING INTO
AREAS FROM I-55 NW THIS AFTERNOON TO BRING A CHANCE OF LIGHT RAIN
SHOWERS. SW WINDS INCREASE TO BREEZY LEVELS TODAY WITH GUSTS
AROUND 30 MPH. HIGHS TO RANGE FROM THE MID 40S OVER THE IL RIVER
VALLEY TO 55 TO 60F IN SE IL FROM I-70 SE DUE TO MORNING SUNSHINE
AND MILDER 850 MB TEMPS YET.
NORTHERN HALF OF CENTRAL IL WILL SEE A CHANCE OF LIGHT RAIN AND
LIGHT SNOW SHOWERS TONIGHT AND SAT AS STRONG LOW PRESSURE MOVES
INTO NW LOWER MI BY SUNSET SAT. THERMAL/THICKNESS PROFILES START
WITH LIGHT RAIN AT SUNSET TONIGHT AND TREND TOWARD LIGHT SNOW
SHOWERS OVERNIGHT NORTH OF LINCOLN AND BACK TO A MIX ON SAT. BRISK
WNW WINDS AND LOW CLOUDS SAT KEEPS TEMPS CHILLY WITH HIGHS ONLY 40
TO 45F WITH UPPER 40S SE OF I-70 IN SE IL. STRONG LOW PRESSURE
MOVES INTO SE CANADA SUNDAY WITH SKIES BECOMING PARTLY SUNNY BY
SUNDAY AFTERNOON AND WEST WINDS WEAKENING DURING SUNDAY AFTERNOON AS
PRESSURE GRADIENT RELAXES. COULD BE SOME FLURRIES NE OF I-74
SUNDAY MORNING. CHILLY YET WITH HIGHS IN THE LOW TO MID 40S.
HIGH PRESSURE RIDGE PASSES OVER IL SUNDAY NIGHT AND PROBABLY THE
COOLEST NIGHT WITH SUBFREEZING LOWS IN THE UPPER 20S/LOWER 30S.
CLOUDS INCREASE AGAIN LATER SUNDAY NIGHT WITH APPROACHING SOUTHERN
STREAM STORM SYSTEM FROM THE SOUTHERN PLAINS.
LONG TERM...MONDAY THROUGH THURSDAY.
00Z GFS MODEL CONTINUES TO BE THE QUICKER MODEL WITH BRINGING QPF
INTO IL BY MONDAY AFTERNOON WHILE THE ECMWF MODEL WAITS UNTIL TUE
AND WEAKER AND FURTHER SOUTHERN WITH LOW PRESSURE. DGEX IN BETWEEN
WITH QPF SPREADING INTO CENTRAL/SE IL BY MONDAY NIGHT AND LEANED
THAT WAY. SO WENT DRY MONDAY AS CLOUDS CONTINUE TO INCREASE. COOL
HIGHS IN THE 40S. LIGHT RAIN CHANCES SPREAD NE ACROSS CENTRAL/SE IL
BY MONDAY NIGHT AND CONTINUE TUE WITH BEST CHANCES OF RAIN AND
HEAVIER QPF SOUTH OF I-72. WHATEVER MODEL YOU LOOK AT...CENTRAL IL
WILL BE ON THE COOL SIDE OF THE STORM SYSTEM WITH LOW PRESSURE
PASSING SOUTH OF AREA. SO COOL HIGHS IN THE 40S AGAIN. AREAS FROM
CANTON TO BLOOMINGTON NORTH MAY BE COOL ENOUGH FOR CHANCE OF LIGHT
SNOW TOO MONDAY NIGHT. LIGHT RAIN CHANCES LOOK TO LINGER WED
ESPECIALLY OVER SE IL WITH INVERTED TROF LINGERING OVER THE OH
VALLEY. LONGWAVE UPPER LEVEL TROF OVER THE NATIONS MID SECTION
NEXT WEEK KEEPS TEMPS NEAR OR BELOW NORMAL.
HUETTL
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KILX 071626
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1026 AM CST FRI NOV 7 2008
.DISCUSSION...
ISSUED 1022 AM CST FRI NOV 7 2008
LOW PRESSURE SYSTEM APPROACHING FROM THE WEST THIS MORNING AFTER
YESTERDAYS COLD FRONT. CLOUDS MOVING INTO THE REGION WITH THE
LOW...AND SLOWLY COVERING UP A SUNNY START TO THE MORNING. CLOUDS
A BIT SLOWER THAN PREVIOUS MODEL RUNS AND HAVE ADJUSTED THE GRIDS
ACCORDINGLY. OTHER THAN THAT...FORECAST IS ON TRACK AND DOING
WELL. SLIGHT CHANCE POPS MORE THAN ENOUGH FOR THE RANDOM SPRINKLE
THAT IS MOVING INTO THE FA ON RADAR IN THE WEST. NOT ANTICIPATING
A MAJOR CHANGE TO THE FORECAST EXCEPT TO POSSIBLY ELIMINATE
MORNING WORDING AROUND MID DAY.
HJS
&&
.AVIATION...
ISSUED 553 AM CST FRI NOV 7 2008
STRONG LOW PRESSURE CONTINUES TO SPIN OVER THE UPPER MIDWEST. LOW
CLOUDS ROTATING AROUND THIS LOW WILL SPILL ACROSS THE REGION...
PROVIDING MVFR OR LOW END VFR CEILINGS FOR MUCH OF THE PERIOD. A
FEW LIGHT SHOWERS OF RAIN OR SNOW ARE POSSIBLE ONCE THE LOW CLOUDS
ROTATE IN...BUT COVERAGE IS TOO LOW TO GO ABOVE A VCSH IN THE TAFS
AT THIS TIME. WINDS WILL BECOME GUSTY OUT OF THE WEST TO SOUTHWEST
TODAY....REACHING 25 KNOTS AT TIMES.
BAK
&&
.PREV DISCUSSION...
ISSUED 330 AM CST FRI NOV 7 2008
BIG CHANGE IN AIRMASS AS MUCH COOLER AIR FILTERING INTO IL THROUGH
THIS WEEKEND. LARGE/STRONG UPPER LEVEL LOW PRESSURE OVER SW MN TO
DOMINATE IL/S WEATHER INTO THIS WEEKEND AS IT DRIFTS SLOWLY EAST
ACROSS THE GREAT LAKES AND SE CANADA THIS WEEKEND. FORECAST
CONCERN IS HOW FAR SOUTH PRECIPITATION GETS AND PRECIPITATION TYPE.
THEN LOOKING AS WX SYSTEM OFF THE WEST COAST MOVING INTO THE
SOUTHERN PLAINS EARLY NEXT WEEK AND EJECTING NE TOWARD THE OHIO
VALLEY TUE. 00Z GFS CONTINUES TO BE FURTHER SOUTH WITH QPF THAN
NAM MODEL INTO THIS WEEKEND AND USED A BLEND WHICH IS SIMILAR TO
ECMWF MODEL.
09Z/3 AM SURFACE MAP SHOWS STRONG 997 MB LOW PRESSURE OVER SW MN
AND VERY STRONG 534 DM 500 MB LOW IN SW MN SO STRONG STORM SYSTEM
THAT HAS PRODUCED BLIZZARD CONDITIONS OVER PARTS OF THE DAKOTAS
HAS BECOME VERTICALLY STACKED. STRONG COLD FRONT HAS MOVED EAST OF
IL INTO EASTERN INDIANA AND CENTRAL KY. LARGE DRY SLOT WITH CLEAR
SKIES OVER IL EARLY THIS MORNING AS AS FAR NORTH AS EASTERN WI AND
LAKE MI. COOLER TEMPS WERE IN THE LOW TO MID 40S WITH GALESBURG
DOWN TO 37F. SW WINDS HAVE TEMPORARILY SUBSIDE TO LESS THAN 10 MPH.
LARGE AREA OF WRAP AROUND LOW CLOUDS WERE SPREADING SE ACROSS IA
AND NW MO AND NEARING THE IL/IA BORDER.
SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
MODELS SIMILAR IN DRIFTING STRONG VERTICALLY STACKED LOW PRESSURE
SYSTEM SLOWLY EASTWARD ACROSS THE MN/IA BORDER TODAY AND OVER
SOUTHERN WI TONIGHT AND INTO CENTRAL LAKE MI BY SAT MORNING.
LOW CLOUDS TO SPREAD SE TOWARD GALESBURG BY 12Z TO DEC/CMI BY NOON
AND INTO SE IL DURING THIS AFTERNOON. STRONG VORT MAX MOVING INTO
AREAS FROM I-55 NW THIS AFTERNOON TO BRING A CHANCE OF LIGHT RAIN
SHOWERS. SW WINDS INCREASE TO BREEZY LEVELS TODAY WITH GUSTS
AROUND 30 MPH. HIGHS TO RANGE FROM THE MID 40S OVER THE IL RIVER
VALLEY TO 55 TO 60F IN SE IL FROM I-70 SE DUE TO MORNING SUNSHINE
AND MILDER 850 MB TEMPS YET.
NORTHERN HALF OF CENTRAL IL WILL SEE A CHANCE OF LIGHT RAIN AND
LIGHT SNOW SHOWERS TONIGHT AND SAT AS STRONG LOW PRESSURE MOVES
INTO NW LOWER MI BY SUNSET SAT. THERMAL/THICKNESS PROFILES START
WITH LIGHT RAIN AT SUNSET TONIGHT AND TREND TOWARD LIGHT SNOW
SHOWERS OVERNIGHT NORTH OF LINCOLN AND BACK TO A MIX ON SAT. BRISK
WNW WINDS AND LOW CLOUDS SAT KEEPS TEMPS CHILLY WITH HIGHS ONLY 40
TO 45F WITH UPPER 40S SE OF I-70 IN SE IL. STRONG LOW PRESSURE
MOVES INTO SE CANADA SUNDAY WITH SKIES BECOMING PARTLY SUNNY BY
SUNDAY AFTERNOON AND WEST WINDS WEAKENING DURING SUNDAY AFTERNOON AS
PRESSURE GRADIENT RELAXES. COULD BE SOME FLURRIES NE OF I-74
SUNDAY MORNING. CHILLY YET WITH HIGHS IN THE LOW TO MID 40S.
HIGH PRESSURE RIDGE PASSES OVER IL SUNDAY NIGHT AND PROBABLY THE
COOLEST NIGHT WITH SUBFREEZING LOWS IN THE UPPER 20S/LOWER 30S.
CLOUDS INCREASE AGAIN LATER SUNDAY NIGHT WITH APPROACHING SOUTHERN
STREAM STORM SYSTEM FROM THE SOUTHERN PLAINS.
LONG TERM...MONDAY THROUGH THURSDAY.
00Z GFS MODEL CONTINUES TO BE THE QUICKER MODEL WITH BRINGING QPF
INTO IL BY MONDAY AFTERNOON WHILE THE ECMWF MODEL WAITS UNTIL TUE
AND WEAKER AND FURTHER SOUTHERN WITH LOW PRESSURE. DGEX IN BETWEEN
WITH QPF SPREADING INTO CENTRAL/SE IL BY MONDAY NIGHT AND LEANED
THAT WAY. SO WENT DRY MONDAY AS CLOUDS CONTINUE TO INCREASE. COOL
HIGHS IN THE 40S. LIGHT RAIN CHANCES SPREAD NE ACROSS CENTRAL/SE IL
BY MONDAY NIGHT AND CONTINUE TUE WITH BEST CHANCES OF RAIN AND
HEAVIER QPF SOUTH OF I-72. WHATEVER MODEL YOU LOOK AT...CENTRAL IL
WILL BE ON THE COOL SIDE OF THE STORM SYSTEM WITH LOW PRESSURE
PASSING SOUTH OF AREA. SO COOL HIGHS IN THE 40S AGAIN. AREAS FROM
CANTON TO BLOOMINGTON NORTH MAY BE COOL ENOUGH FOR CHANCE OF LIGHT
SNOW TOO MONDAY NIGHT. LIGHT RAIN CHANCES LOOK TO LINGER WED
ESPECIALLY OVER SE IL WITH INVERTED TROF LINGERING OVER THE OH
VALLEY. LONGWAVE UPPER LEVEL TROF OVER THE NATIONS MID SECTION
NEXT WEEK KEEPS TEMPS NEAR OR BELOW NORMAL.
HUETTL
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 071212
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
612 AM CST FRI NOV 7 2008
.DISCUSSION...
251 AM CST
POST FRONTAL CLEAR SLOT SHUD LAST THRU SUNRISE BUT SHUD SLOWLY ERODE
THRU THE MORNING AS THE BACKWASH UPR LOW WRAPAROUND WORKS EAST
ACROSS NRN IL. EMBEDDED IN THIS COMMA HEAD ARE MINUS 850 TEMPS
WRINGING OUT RESIDUAL MSTR INTO LIGHT RAIN AND EVEN SNOW SHOWERS
ACROSS IOWA. DAYTIME SENSIBLE HEATING SHUD COUNTERACT THE FIRST
WAVES OF CAA IN THE MRNG...BUT WILL LIKELY SUCCUMB TO FALLING MID TO
LATE AFTN TEMPS AS CLOUD COVER THICKENS. CONSIDERING BOUNDARY LAYER
WARMING...WUD NOT BOTHER WITH SNOW FOR MOST OF AREA UNTIL AFTER DARK
THIS EVENING. WILL PROBLY LEAVE IN RAIN OR SNOW IN NORTH CENTRAL IL
FOR THIS AFTN BUT NOT TRANSITION TO SNOW COMPLETELY UNTIL TONIGHT.
BOUNDARY LAYERED WET BULB ZERO CLOSES IN ACROSS NRN IL LATE TONIGHT
INTO SAT MRNG ON MODELS...BUT SEEMS TO BE CURRENTLY TRANSITIONING TO
SNOW AHEAD OF PROPOSED WBZ IN NWRN IOWA ALREADY. MOST MODELS
OUTPUTTING A TENTH TO HALF INCH OF SNOW NORTH OF I-88 BY SAT MRNG
BUT WITH 4 INCH SOIL TEMPS STILL AROUND 50...EXPECT THE LOWER VALUE
AT BEST...AND THIS ONLY TEMPORARILY IN A HEAVY SNOW BURST. EXPECTING
LOW TEMPS SAT MRNG STILL HOVERING AT OR ABOVE FREEZING ANYWAY.
UPR LOW TRACKING SLOWLY OFF TO NRN LOWER MICHIGAN SATURDAY AND
VEERING WINDS FROM SW TO WEST WHILE BEARING FURTHER CAA WITH 850
TEMPS DROPPING ANOTHER COUPLE OF DEGREES. RAIN AND SNOW MIX SHUD
TRANSITION TO FLURRIES SAT EVENING WITH THIS INCREASED CHILLING.
UPPER LOW PROGRESSION STILL REMAINS SLOW ON SUNDAY WITH PROGRESS
ACROSS LAKE HURON THRU SUNDAY MRNG...THEN INTO SW QUEBEC SUNDAY
NIGHT. THIS MOVE SHUD BE FAR ENUF TO END PCPN AND PERMIT SOME
CLEARING TO MOVE IN FROM THE WEST.
CLEARING IS SHORT LIVED HOWEVER AS A SYSTEM DEEPENING NEAR THE TX
PANHANDLE SPEWS WAA CI AND AC NWD INTO THE MID MS VLY MONDAY
AFTERNOON. MODELS HAVE BEEN YO-YO-ING THIS SYSTEM IN TIME AND
GEOGRAPHY THE LAST COUPLE OF DAYS. TONIGHT IS NO EXCEPTION WITH GFS
TAKING A CLOSED SFC LOW ACROSS ST. LOUIS TUES MRNG AND ECMWF WORKING
A RATHER LOOSE INVERTED TROF ACROSS THE LOWER MS VLY NEAR THAT TIME.
THUS HAVE CHANGED THE EXTENDED VERY LITTLE...KEEPING PCPN TO A
MINIMUM ACROSS THE SOUTH PORTION OF CWA.
RLB
&&
.AVIATION...
600 AM CST
12Z TAFS...DRY SLOT STILL COVERS WRN INDIANA AND MUCH OF ILLINOIS
WITH THE EXCEPTION OF THE FAR WRN SXNS ALG THE MS RIVER. THE UPPER
LOW CENTER IS NEARLY STATIONARY OVER SWRN MN...BUT ALL OF THE
FORECAST MODELS INDICATE THAT IT SHOULD KICK OUT NEWD ACROSS CNTRL
WISCONSIN TODAY. GIVEN THE LACK OF PROGRESS OVERNIGHT...HAVE
PUSHED BACK THE INCREASING CLOUD COVER AND INTRODUCTION OF PCPN AT
ALL SITES BY A FEW HOURS.
HAVE MADE LITTLE CHANGE TO THE GOING TAFS WITH THE EXCEPTION OF
PREVIOUSLY MENTIONED TIMING DELAY. STILL EXPECT THE MAIN
STRATOCU DECK TO BEGIN TO OVERSPREAD THE TERMINALS BY MID MORNING
WITH GRADUAL LOWERING WITH TIME AS THE STRONG COLD AIR ADVECTION
SETS UP. HAVE SLIGHTLY ADJUSTED CEILINGS TO INTRODUCE MVFR
CONDITIONS DURG THE LATE AFTERNOON AND EARLY EVENING.
PCPN WILL GRADUALLY SPREAD FROM THE WEST TO EAST...MOVING INTO THE
RFD AREA LATE AFTERNOON AND THE CHICAGO AREA TERMINALS BY EARLY
EVENING. GIVEN THAT THE FREEZING LEVEL IS SHOWN DOWN TO AROUND
1000 FEET AGL BY EARLY AFTERNOON...HAVE STARTED OUT PCPN AS
LIQUID...BUT SHOULD QUICKLY CHANGE OVER TO A RAIN AND SNOW MIX.
KREIN
&&
.MARINE...
320 AM CST
DEEP LOW PRESSURE OVER SOUTHERN MINNESOTA WILL MOVE SLOWLY
NORTHEAST TO NORTHERN WISCONSIN THIS AFTERNOON. THE LOW WILL
CONTINUE TO TRACK NORTHEAST...TO EASTERN ONTARIO BY SATURDAY
AFTERNOON. A STRONG COLD FRONT ASSOCIATED WITH THIS LOW WILL SWEEP
ACROSS LAKE MICHIGAN TODAY...USHERING IN COLD AIR AND INCREASING
WINDS. WINDS OVER THE SOUTHERN PORTION OF THE LAKE SHOULD REACH
LOWER END GALES BY SATURDAY AFTERNOON AND CONTINUE THROUGH EARLY
SUNDAY MORNING BEFORE TAPERING OFF. MEANWHILE...A RIDGE OF HIGH
PRESSURE WILL BUILD SOUTH OUT OF WINNIPEG AND INTO THE NORTHERN
PLAINS SATURDAY AND SUNDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 PM FRIDAY TO 6 AM SUNDAY.
GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM SATURDAY TO 3 AM
SUNDAY.
&&
$$
000
FXUS63 KILX 071153
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
553 AM CST FRI NOV 7 2008
.DISCUSSION...
ISSUED 330 AM CST FRI NOV 7 2008
BIG CHANGE IN AIRMASS AS MUCH COOLER AIR FILTERING INTO IL THROUGH
THIS WEEKEND. LARGE/STRONG UPPER LEVEL LOW PRESSURE OVER SW MN TO
DOMINATE IL/S WEATHER INTO THIS WEEKEND AS IT DRIFTS SLOWLY EAST
ACROSS THE GREAT LAKES AND SE CANADA THIS WEEKEND. FORECAST
CONCERN IS HOW FAR SOUTH PRECIPITATION GETS AND PRECIPITATION TYPE.
THEN LOOKING AS WX SYSTEM OFF THE WEST COAST MOVING INTO THE
SOUTHERN PLAINS EARLY NEXT WEEK AND EJECTING NE TOWARD THE OHIO
VALLEY TUE. 00Z GFS CONTINUES TO BE FURTHER SOUTH WITH QPF THAN
NAM MODEL INTO THIS WEEKEND AND USED A BLEND WHICH IS SIMILAR TO
ECMWF MODEL.
09Z/3 AM SURFACE MAP SHOWS STRONG 997 MB LOW PRESSURE OVER SW MN
AND VERY STRONG 534 DM 500 MB LOW IN SW MN SO STRONG STORM SYSTEM
THAT HAS PRODUCED BLIZZARD CONDITIONS OVER PARTS OF THE DAKOTAS
HAS BECOME VERTICALLY STACKED. STRONG COLD FRONT HAS MOVED EAST OF
IL INTO EASTERN INDIANA AND CENTRAL KY. LARGE DRY SLOT WITH CLEAR
SKIES OVER IL EARLY THIS MORNING AS AS FAR NORTH AS EASTERN WI AND
LAKE MI. COOLER TEMPS WERE IN THE LOW TO MID 40S WITH GALESBURG
DOWN TO 37F. SW WINDS HAVE TEMPORARILY SUBSIDE TO LESS THAN 10 MPH.
LARGE AREA OF WRAP AROUND LOW CLOUDS WERE SPREADING SE ACROSS IA
AND NW MO AND NEARING THE IL/IA BORDER.
SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
MODELS SIMILAR IN DRIFTING STRONG VERTICALLY STACKED LOW PRESSURE
SYSTEM SLOWLY EASTWARD ACROSS THE MN/IA BORDER TODAY AND OVER
SOUTHERN WI TONIGHT AND INTO CENTRAL LAKE MI BY SAT MORNING.
LOW CLOUDS TO SPREAD SE TOWARD GALESBURG BY 12Z TO DEC/CMI BY NOON
AND INTO SE IL DURING THIS AFTERNOON. STRONG VORT MAX MOVING INTO
AREAS FROM I-55 NW THIS AFTERNOON TO BRING A CHANCE OF LIGHT RAIN
SHOWERS. SW WINDS INCREASE TO BREEZY LEVELS TODAY WITH GUSTS
AROUND 30 MPH. HIGHS TO RANGE FROM THE MID 40S OVER THE IL RIVER
VALLEY TO 55 TO 60F IN SE IL FROM I-70 SE DUE TO MORNING SUNSHINE
AND MILDER 850 MB TEMPS YET.
NORTHERN HALF OF CENTRAL IL WILL SEE A CHANCE OF LIGHT RAIN AND
LIGHT SNOW SHOWERS TONIGHT AND SAT AS STRONG LOW PRESSURE MOVES
INTO NW LOWER MI BY SUNSET SAT. THERMAL/THICKNESS PROFILES START
WITH LIGHT RAIN AT SUNSET TONIGHT AND TREND TOWARD LIGHT SNOW
SHOWERS OVERNIGHT NORTH OF LINCOLN AND BACK TO A MIX ON SAT. BRISK
WNW WINDS AND LOW CLOUDS SAT KEEPS TEMPS CHILLY WITH HIGHS ONLY 40
TO 45F WITH UPPER 40S SE OF I-70 IN SE IL. STRONG LOW PRESSURE
MOVES INTO SE CANADA SUNDAY WITH SKIES BECOMING PARTLY SUNNY BY
SUNDAY AFTERNOON AND WEST WINDS WEAKENING DURING SUNDAY AFTERNOON AS
PRESSURE GRADIENT RELAXES. COULD BE SOME FLURRIES NE OF I-74
SUNDAY MORNING. CHILLY YET WITH HIGHS IN THE LOW TO MID 40S.
HIGH PRESSURE RIDGE PASSES OVER IL SUNDAY NIGHT AND PROBABLY THE
COOLEST NIGHT WITH SUBFREEZING LOWS IN THE UPPER 20S/LOWER 30S.
CLOUDS INCREASE AGAIN LATER SUNDAY NIGHT WITH APPROACHING SOUTHERN
STREAM STORM SYSTEM FROM THE SOUTHERN PLAINS.
LONG TERM...MONDAY THROUGH THURSDAY.
00Z GFS MODEL CONTINUES TO BE THE QUICKER MODEL WITH BRINGING QPF
INTO IL BY MONDAY AFTERNOON WHILE THE ECMWF MODEL WAITS UNTIL TUE
AND WEAKER AND FURTHER SOUTHERN WITH LOW PRESSURE. DGEX IN BETWEEN
WITH QPF SPREADING INTO CENTRAL/SE IL BY MONDAY NIGHT AND LEANED
THAT WAY. SO WENT DRY MONDAY AS CLOUDS CONTINUE TO INCREASE. COOL
HIGHS IN THE 40S. LIGHT RAIN CHANCES SPREAD NE ACROSS CENTRAL/SE IL
BY MONDAY NIGHT AND CONTINUE TUE WITH BEST CHANCES OF RAIN AND
HEAVIER QPF SOUTH OF I-72. WHATEVER MODEL YOU LOOK AT...CENTRAL IL
WILL BE ON THE COOL SIDE OF THE STORM SYSTEM WITH LOW PRESSURE
PASSING SOUTH OF AREA. SO COOL HIGHS IN THE 40S AGAIN. AREAS FROM
CANTON TO BLOOMINGTON NORTH MAY BE COOL ENOUGH FOR CHANCE OF LIGHT
SNOW TOO MONDAY NIGHT. LIGHT RAIN CHANCES LOOK TO LINGER WED
ESPECIALLY OVER SE IL WITH INVERTED TROF LINGERING OVER THE OH
VALLEY. LONGWAVE UPPER LEVEL TROF OVER THE NATIONS MID SECTION
NEXT WEEK KEEPS TEMPS NEAR OR BELOW NORMAL.
HUETTL
&&
.AVIATION...
ISSUED 553 AM CST FRI NOV 7 2008
STRONG LOW PRESSURE CONTINUES TO SPIN OVER THE UPPER MIDWEST. LOW
CLOUDS ROTATING AROUND THIS LOW WILL SPILL ACROSS THE REGION...
PROVIDING MVFR OR LOW END VFR CEILINGS FOR MUCH OF THE PERIOD. A
FEW LIGHT SHOWERS OF RAIN OR SNOW ARE POSSIBLE ONCE THE LOW CLOUDS
ROTATE IN...BUT COVERAGE IS TOO LOW TO GO ABOVE A VCSH IN THE TAFS
AT THIS TIME. WINDS WILL BECOME GUSTY OUT OF THE WEST TO SOUTHWEST
TODAY....REACHING 25 KNOTS AT TIMES.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KILX 070929
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
329 AM CST FRI NOV 7 2008
.DISCUSSION...
ISSUED 330 AM CST FRI NOV 7 2008
BIG CHANGE IN AIRMASS AS MUCH COOLER AIR FILTERING INTO IL THROUGH
THIS WEEKEND. LARGE/STRONG UPPER LEVEL LOW PRESSURE OVER SW MN TO
DOMINATE IL/S WEATHER INTO THIS WEEKEND AS IT DRIFTS SLOWLY EAST
ACROSS THE GREAT LAKES AND SE CANADA THIS WEEKEND. FORECAST
CONCERN IS HOW FAR SOUTH PRECIPITATION GETS AND PRECIPITATION TYPE.
THEN LOOKING AS WX SYSTEM OFF THE WEST COAST MOVING INTO THE
SOUTHERN PLAINS EARLY NEXT WEEK AND EJECTING NE TOWARD THE OHIO
VALLEY TUE. 00Z GFS CONTINUES TO BE FURTHER SOUTH WITH QPF THAN
NAM MODEL INTO THIS WEEKEND AND USED A BLEND WHICH IS SIMILAR TO
ECMWF MODEL.
09Z/3 AM SURFACE MAP SHOWS STRONG 997 MB LOW PRESSURE OVER SW MN
AND VERY STRONG 534 DM 500 MB LOW IN SW MN SO STRONG STORM SYSTEM
THAT HAS PRODUCED BLIZZARD CONDITIONS OVER PARTS OF THE DAKOTAS
HAS BECOME VERTICALLY STACKED. STRONG COLD FRONT HAS MOVED EAST OF
IL INTO EASTERN INDIANA AND CENTRAL KY. LARGE DRY SLOT WITH CLEAR
SKIES OVER IL EARLY THIS MORNING AS AS FAR NORTH AS EASTERN WI AND
LAKE MI. COOLER TEMPS WERE IN THE LOW TO MID 40S WITH GALESBURG
DOWN TO 37F. SW WINDS HAVE TEMPORARILY SUBSIDE TO LESS THAN 10 MPH.
LARGE AREA OF WRAP AROUND LOW CLOUDS WERE SPREADING SE ACROSS IA
AND NW MO AND NEARING THE IL/IA BORDER.
SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
MODELS SIMILAR IN DRIFTING STRONG VERTICALLY STACKED LOW PRESSURE
SYSTEM SLOWLY EASTWARD ACROSS THE MN/IA BORDER TODAY AND OVER
SOUTHERN WI TONIGHT AND INTO CENTRAL LAKE MI BY SAT MORNING.
LOW CLOUDS TO SPREAD SE TOWARD GALESBURG BY 12Z TO DEC/CMI BY NOON
AND INTO SE IL DURING THIS AFTERNOON. STRONG VORT MAX MOVING INTO
AREAS FROM I-55 NW THIS AFTERNOON TO BRING A CHANCE OF LIGHT RAIN
SHOWERS. SW WINDS INCREASE TO BREEZY LEVELS TODAY WITH GUSTS
AROUND 30 MPH. HIGHS TO RANGE FROM THE MID 40S OVER THE IL RIVER
VALLEY TO 55 TO 60F IN SE IL FROM I-70 SE DUE TO MORNING SUNSHINE
AND MILDER 850 MB TEMPS YET.
NORTHERN HALF OF CENTRAL IL WILL SEE A CHANCE OF LIGHT RAIN AND
LIGHT SNOW SHOWERS TONIGHT AND SAT AS STRONG LOW PRESSURE MOVES
INTO NW LOWER MI BY SUNSET SAT. THERMAL/THICKNESS PROFILES START
WITH LIGHT RAIN AT SUNSET TONIGHT AND TREND TOWARD LIGHT SNOW
SHOWERS OVERNIGHT NORTH OF LINCOLN AND BACK TO A MIX ON SAT. BRISK
WNW WINDS AND LOW CLOUDS SAT KEEPS TEMPS CHILLY WITH HIGHS ONLY 40
TO 45F WITH UPPER 40S SE OF I-70 IN SE IL. STRONG LOW PRESSURE
MOVES INTO SE CANADA SUNDAY WITH SKIES BECOMING PARTLY SUNNY BY
SUNDAY AFTERNOON AND WEST WINDS WEAKING DURING SUNDAY AFTERNOON AS
PRESSURE GRADIENT RELAXES. COULD BE SOME FLURRIES NE OF I-74
SUNDAY MORNING. CHILLY YET WITH HIGHS IN THE LOW TO MID 40S.
HIGH PRESSURE RIDGE PASSES OVER IL SUNDAY NIGHT AND PROBABLY THE
COOLEST NIGHT WITH SUBFREEZING LOWS IN THE UPPER 20S/LOWER 30S.
CLOUDS INCREASE AGAIN LATER SUNDAY NIGHT WITH APPROACHING SOUTHERN
STREAM STORM SYSTEM FROM THE SOUTHERN PLAINS.
LONG TERM...MONDAY THROUGH THURSDAY.
00Z GFS MODEL CONTINUES TO BE THE QUICKER MODEL WITH BRINGING QPF
INTO IL BY MONDAY AFTERNOON WHILE THE ECMWF MODEL WAITS UNTIL TUE
AND WEAKER AND FURTHER SOUTHERN WITH LOW PRESSURE. DGEX IN BETWEEN
WITH QPF SPREADING INTO CENTRAL/SE IL BY MONDAY NIGHT AND LEANED
THAT WAY. SO WENT DRY MONDAY AS CLOUDS CONTINUE TO INCREASE. COOL
HIGHS IN THE 40S. LIGHT RAIN CHANCES SPREAD NE ACROSS CENTRAL/SE IL
BY MONDAY NIGHT AND CONTINUE TUE WITH BEST CHANCES OF RAIN AND
HEAVIER QPF SOUTH OF I-72. WHATEVER MODEL YOU LOOK AT...CENTRAL IL
WILL BE ON THE COOL SIDE OF THE STORM SYSTEM WITH LOW PRESSURE
PASSING SOUTH OF AREA. SO COOL HIGHS IN THE 40S AGAIN. AREAS FROM
CANTON TO BLOOMINGTON NORTH MAY BE COOL ENOUGH FOR CHANCE OF LIGHT
SNOW TOO MONDAY NIGHT. LIGHT RAIN CHANCES LOOK TO LINGER WED
ESPECIALLY OVER SE IL WITH INVERTED TROF LINGERING OVER THE OH
VALLEY. LONGWAVE UPPER LEVEL TROF OVER THE NATIONS MID SECTION
NEXT WEEK KEEPS TEMPS NEAR OR BELOW NORMAL.
HUETTL
&&
.AVIATION...
ISSUED 1139 PM CST THU NOV 6 2008...FOR THE 06Z TAFS
OUR CWA WILL BE UNDER THE INFLUENCE OF THE DRY SLOT FOR THE REST
OF THE NIGHT...EXCEPT FOR THE NW CORNER OF THE CWA. PIA MAY SEE
SOME 5K FT CLOUDS DRIFT BY FROM TIME TO TIME...BUT NO CIGS ARE
EXPECTED UNTIL FRIDAY MORNING AROUND 15Z. THE 00Z GUIDANCE IS
FOCUSING THE HIGHER CHANCES FOR PRECIP DURING THE AFTERNOON.
STILL...MEASURABLE PRECIP WILL BE HARD TO COME BY TOMORROW...SO
WILL STAY THE COURSE WITH VCSH IN THE TAFS THROUGH 00Z FRIDAY
EVENING. WILL KEEP A 4-5K FT CIG ALL DAY FRIDAY...WITH NO
RESTRICTION TO VIS. SOME FLAKES OF SNOW WILL NOT BE OUT OF THE
QUESTION...BUT NOT SIGNIFICANT. VCSH COVERS RAIN OR SNOW SHOWERS.
SOME LIGHT FOG IN CMI MAY LINGER FOR A FEW HOURS TONIGHT...BUT DO
NOT EXPECT ANY LOWER THAN 3 MILES. WILL KEEP PREVAILING 5SM
THROUGH MORNING.
SOUTHWEST WINDS WILL INCREASE TOMORROW AS THE PRESSURE GRADIENT
TIGHTENS NEAR THE SURFACE LOW. GUSTS MAY REACH NEAR 30 KTS AT
TIMES.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 070924
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
324 AM CST FRI NOV 7 2008
.DISCUSSION...
251 AM CST
POST FRONTAL CLEAR SLOT SHUD LAST THRU SUNRISE BUT SHUD SLOWLY ERODE
THRU THE MORNING AS THE BACKWASH UPR LOW WRAPAROUND WORKS EAST
ACROSS NRN IL. EMBEDDED IN THIS COMMA HEAD ARE MINUS 850 TEMPS
WRINGING OUT RESIDUAL MSTR INTO LIGHT RAIN AND EVEN SNOW SHOWERS
ACROSS IOWA. DAYTIME SENSIBLE HEATING SHUD COUNTERACT THE FIRST
WAVES OF CAA IN THE MRNG...BUT WILL LIKELY SUCCUMB TO FALLING MID TO
LATE AFTN TEMPS AS CLOUD COVER THICKENS. CONSIDERING BOUNDARY LAYER
WARMING...WUD NOT BOTHER WITH SNOW FOR MOST OF AREA UNTIL AFTER DARK
THIS EVENING. WILL PROBLY LEAVE IN RAIN OR SNOW IN NORTH CENTRAL IL
FOR THIS AFTN BUT NOT TRANSITION TO SNOW COMPLETELY UNTIL TONIGHT.
BOUNDARY LAYERED WET BULB ZERO CLOSES IN ACROSS NRN IL LATE TONIGHT
INTO SAT MRNG ON MODELS...BUT SEEMS TO BE CURRENTLY TRANSITIONING TO
SNOW AHEAD OF PROPOSED WBZ IN NWRN IOWA ALREADY. MOST MODELS
OUTPUTTING A TENTH TO HALF INCH OF SNOW NORTH OF I-88 BY SAT MRNG
BUT WITH 4 INCH SOIL TEMPS STILL AROUND 50...EXPECT THE LOWER VALUE
AT BEST...AND THIS ONLY TEMPORARILY IN A HEAVY SNOW BURST. EXPECTING
LOW TEMPS SAT MRNG STILL HOVERING AT OR ABOVE FREEZING ANYWAY.
UPR LOW TRACKING SLOWLY OFF TO NRN LOWER MICHIGAN SATURDAY AND
VEERING WINDS FROM SW TO WEST WHILE BEARING FURTHER CAA WITH 850
TEMPS DROPPING ANOTHER COUPLE OF DEGREES. RAIN AND SNOW MIX SHUD
TRANSITION TO FLURRIES SAT EVENING WITH THIS INCREASED CHILLING.
UPPER LOW PROGRESSION STILL REMAINS SLOW ON SUNDAY WITH PROGRESS
ACROSS LAKE HURON THRU SUNDAY MRNG...THEN INTO SW QUEBEC SUNDAY
NIGHT. THIS MOVE SHUD BE FAR ENUF TO END PCPN AND PERMIT SOME
CLEARING TO MOVE IN FROM THE WEST.
CLEARING IS SHORT LIVED HOWEVER AS A SYSTEM DEEPENING NEAR THE TX
PANHANDLE SPEWS WAA CI AND AC NWD INTO THE MID MS VLY MONDAY
AFTERNOON. MODELS HAVE BEEN YO-YO-ING THIS SYSTEM IN TIME AND
GEOGRAPHY THE LAST COUPLE OF DAYS. TONIGHT IS NO EXCEPTION WITH GFS
TAKING A CLOSED SFC LOW ACROSS ST. LOUIS TUES MRNG AND ECMWF WORKING
A RATHER LOOSE INVERTED TROF ACROSS THE LOWER MS VLY NEAR THAT TIME.
THUS HAVE CHANGED THE EXTENDED VERY LITTLE...KEEPING PCPN TO A
MINIMUM ACROSS THE SOUTH PORTION OF CWA.
RLB
&&
.AVIATION...
1024 PM CST
06Z TAFORS...COLD FRONT SWINGING EAST ACROSS LAKE MICHIGAN AT 04Z
WITH STRONG DRYING CONTINUING TO SPREAD WEST TO EAST ACROSS
ILLINOIS. WITH MID AND UPPER LOW CENTERS ONLY MAKING VERY SLOW
EASTWARD PROGRESS ALONG THE MINNESOTA-IOWA BORDER OVERNIGHT PER
LATEST MODEL RUNS THE ASSOCIATED CLOUDINESS...THE EASTERN EXTEND
OF WHICH WAS ROTATING NORTH- NORTHEASTWARD ACROSS FAR NORTHWEST
ILLINOIS AND SOUTHWESTERN WISCONSIN...WILL ONLY JUST CLIP THE KRFD
AREA WHILE THE OTHER LOCAL TERMINALS REMAIN UNDER THE CLEAR SKY OF
THE DRY SLOT.
BY 080000 THE MID LEVEL LOW IS PROGGED TO BE OVER FAR SOUTHEAST
MINNESOTA/NORTHEAST IOWA/SOUTHWEST WISCONSIN WITH A TROUGH AXIS
ROTATING INTO NORTHWEST AND WEST CENTRAL ILLINOIS. SIGNIFICANT
LOW LEVEL COLD AIR ADVECTION WELL ALSO BE WELL UNDERWAY FROM IA
AND NORTHERN MO ACROSS IL AND SOUTHERN WI DURING THE DAY FRIDAY.
EXPECT THE MAIN STRATOCUMULUS DECK TO REACH THE LOCAL TERMINALS BY
MID FRIDAY MORNING WITH GRADUAL LOWERING WITH TIME AS THE STRONG
COLD AIR ADVECTION CONTINUES...THOUGH HAVE KEPT CEILINGS VFR
UNTIL LATER AFTERNOON AT KRFD AND UNTIL EVENING IN THE CHICAGO
AREA.
SHOWERS PRECEDING THE MID LEVEL TROUGH WILL BE APPROACHING FROM
THE WEST WITH TIME AND EXPECT THEM INTO KRFD FOR EARLY AFTERNOON
AND INTO CHICAGO TERMINALS BY EVENING...WITH OTHER SHOWERS NEAR/UNDER
THE MID LEVEL LOW SPREADING ACROSS NORTHERN ILLINOIS LATE AFTERNOON
AND FOR THE EVENING. GIVEN THAT THE FREEZING LEVEL IS SHOWN DOWN
TO AROUND 1000 FEET ABOVE GROUND LEVEL BY 071800 BY THE LATEST NAM
AND GFS MODEL RUNS HAVE PRECIPITATION AS MIXED RAIN AND SNOW
SHOWERS. ANY ADDITIONAL SNOW FLURRIES/SNOW SHOWERS NOT EXPECTED
INTO KORD UNTIL OVERNIGHT FRIDAY NIGHT/EARLY SATURDAY MORNING WHEN
THE MID LEVEL LOW WILL BE MOVING NORTHEASTWARD TO EAST CENTRAL
WISCONSIN.
TRS
&&
.MARINE...
320 AM CST
DEEP LOW PRESSURE OVER SOUTHERN MINNESOTA WILL MOVE SLOWLY
NORTHEAST TO NORTHERN WISCONSIN THIS AFTERNOON. THE LOW WILL
CONTINUE TO TRACK NORTHEAST...TO EASTERN ONTARIO BY SATURDAY
AFTERNOON. A STRONG COLD FRONT ASSOCIATED WITH THIS LOW WILL SWEEP
ACROSS LAKE MICHIGAN TODAY...USHERING IN COLD AIR AND INCREASING
WINDS. WINDS OVER THE SOUTHERN PORTION OF THE LAKE SHOULD REACH
LOWER END GALES BY SATURDAY AFTERNOON AND CONTINUE THROUGH EARLY
SUNDAY MORNING BEFORE TAPERING OFF. MEANWHILE...A RIDGE OF HIGH
PRESSURE WILL BUILD SOUTH OUT OF WINNIPEG AND INTO THE NORTHERN
PLAINS SATURDAY AND SUNDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM SATURDAY TO 3 AM
SUNDAY.
&&
$$
000
FXUS63 KLOT 070852
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
252 AM CST FRI NOV 7 2008
.DISCUSSION...
251 AM CST
POST FRONTAL CLEAR SLOT SHUD LAST THRU SUNRISE BUT SHUD SLOWLY ERODE
THRU THE MORNING AS THE BACKWASH UPR LOW WRAPAROUND WORKS EAST
ACROSS NRN IL. EMBEDDED IN THIS COMMA HEAD ARE MINUS 850 TEMPS
WRINGING OUT RESIDUAL MSTR INTO LIGHT RAIN AND EVEN SNOW SHOWERS
ACROSS IOWA. DAYTIME SENSIBLE HEATING SHUD COUNTERACT THE FIRST
WAVES OF CAA IN THE MRNG...BUT WILL LIKELY SUCCOMB TO FALLING MID TO
LATE AFTN TEMPS AS CLOUD COVER THICKENS. CONSIDERING BOUNDARY LAYER
WARMING...WUD NOT BOTHER WITH SNOW FOR MOST OF AREA UNTIL AFTER DARK
THIS EVENING. WILL PROBLY LEAVE IN RAIN OR SNOW IN NORTH CENTRAL IL
FOR THIS AFTN BUT NOT TRANSITION TO SNOW COMPLETELY UNTIL TONIGHT.
BOUNDARY LAYERED WET BULB ZERO CLOSES IN ACROSS NRN IL LATE TONIGHT
INTO SAT MRNG ON MODELS...BUT SEEMS TO BE CURRENTLY TRANSITIONING TO
SNOW AHEAD OF PROPOSED WBZ IN NWRN IOWA ALREADY. MOST MODELS
OUTPUTTING A TENTH TO HALF INCH OF SNOW NORTH OF I-88 BY SAT MRNG
BUT WITH 4 INCH SOIL TEMPS STILL AROUND 50...EXPECT THE LOWER VALUE
AT BEST...AND THIS ONLY TEMPORARILY IN A HEAVY SNOW BURST. EXPECTING
LOW TEMPS SAT MRNG STILL HOVERING AT OR ABOVE FREEZING ANYWAY.
UPR LOW TRACKING SLOWLY OFF TO NRN LOWER MICHIGAN SATURDAY AND
VEERING WINDS FROM SW TO WEST WHILE BEARING FURTHER CAA WITH 850
TEMPS DROPPING ANOTHER COUPLE OF DEGREES. RAIN AND SNOW MIX SHUD
TRANSITION TO FLURRIES SAT EVENING WITH THIS INCREASED CHILLING.
UPPER LOW PROGRESSION STILL REMAINS SLOW ON SUNDAY WITH PROGRESS
ACROSS LAKE HURON THRU SUNDAY MRNG...THEN INTO SW QUEBEC SUNDAY
NIGHT. THIS MOVE SHUD BE FAR ENUF TO END PCPN AND PERMIT SOME
CLEARING TO MOVE IN FROM THE WEST.
CLEARING IS SHORT LIVED HOWEVER AS A SYSTEM DEEPENING NEAR THE TX
PANHANDLE SPEWS WAA CI AND AC NWD INTO THE MID MS VLY MONDAY
AFTERNOON. MODELS HAVE BEEN YO-YO-ING THIS SYSTEM IN TIME AND
GEOGRAPHY THE LAST COUPLE OF DAYS. TONIGHT IS NO EXCEPTION WITH GFS
TAKING A CLOSED SFC LOW ACROSS ST. LOUIS TUES MRNG AND ECMWF WORKING
A RATHER LOOSE INVERTED TROF ACROSS THE LOWER MS VLY NEAR THAT TIME.
THUS HAVE CHANGED THE EXTENDED VERY LITTLE...KEEPING PCPN TO A
MINIMUM ACROSS THE SOUTH PORTION OF CWA.
RLB
&&
.AVIATION...
1024 PM CST
06Z TAFORS...COLD FRONT SWINGING EAST ACROSS LAKE MICHIGAN AT 04Z
WITH STRONG DRYING CONTINUING TO SPREAD WEST TO EAST ACROSS
ILLINOIS. WITH MID AND UPPER LOW CENTERS ONLY MAKING VERY SLOW
EASTWARD PROGRESS ALONG THE MINNESOTA-IOWA BORDER OVERNIGHT PER
LATEST MODEL RUNS THE ASSOCIATED CLOUDINESS...THE EASTERN EXTEND
OF WHICH WAS ROTATING NORTH- NORTHEASTWARD ACROSS FAR NORTHWEST
ILLINOIS AND SOUTHWESTERN WISCONSIN...WILL ONLY JUST CLIP THE KRFD
AREA WHILE THE OTHER LOCAL TERMINALS REMAIN UNDER THE CLEAR SKY OF
THE DRY SLOT.
BY 080000 THE MID LEVEL LOW IS PROGGED TO BE OVER FAR SOUTHEAST
MINNESOTA/NORTHEAST IOWA/SOUTHWEST WISCONSIN WITH A TROUGH AXIS
ROTATING INTO NORTHWEST AND WEST CENTRAL ILLINOIS. SIGNIFICANT
LOW LEVEL COLD AIR ADVECTION WELL ALSO BE WELL UNDERWAY FROM IA
AND NORTHERN MO ACROSS IL AND SOUTHERN WI DURING THE DAY FRIDAY.
EXPECT THE MAIN STRATOCUMULUS DECK TO REACH THE LOCAL TERMINALS BY
MID FRIDAY MORNING WITH GRADUAL LOWERING WITH TIME AS THE STRONG
COLD AIR ADVECTION CONTINUES...THOUGH HAVE KEPT CEILINGS VFR
UNTIL LATER AFTERNOON AT KRFD AND UNTIL EVENING IN THE CHICAGO
AREA.
SHOWERS PRECEDING THE MID LEVEL TROUGH WILL BE APPROACHING FROM
THE WEST WITH TIME AND EXPECT THEM INTO KRFD FOR EARLY AFTERNOON
AND INTO CHICAGO TERMINALS BY EVENING...WITH OTHER SHOWERS NEAR/UNDER
THE MID LEVEL LOW SPREADING ACROSS NORTHERN ILLINOIS LATE AFTERNOON
AND FOR THE EVENING. GIVEN THAT THE FREEZING LEVEL IS SHOWN DOWN
TO AROUND 1000 FEET ABOVE GROUND LEVEL BY 071800 BY THE LATEST NAM
AND GFS MODEL RUNS HAVE PRECIPITATION AS MIXED RAIN AND SNOW
SHOWERS. ANY ADDITIONAL SNOW FLURRIES/SNOW SHOWERS NOT EXPECTED
INTO KORD UNTIL OVERNIGHT FRIDAY NIGHT/EARLY SATURDAY MORNING WHEN
THE MID LEVEL LOW WILL BE MOVING NORTHEASTWARD TO EAST CENTRAL
WISCONSIN.
TRS
&&
.MARINE...
200 PM CST
A LOW WAS WESTERN MINNESOTA THIS AFTERNOON. THIS LOW WILL MOVE INTO
NORTHWEST WISCONSIN BY FRIDAY AFTERNOON. THIS LOW WILL CAUSE STRONG
SOUTH WIND 15 TO 25 KNOTS OVER LAKE MICHIGAN TONIGHT. BY SATURDAY
AFTERNOON.THE LOW WILL BE OVER EASTERN ONTARIO. A HIGH WILL EXTEND
SOUTH FROM MANITOBA TO THE DAKOTA BY SATURDAY AFTERNOON. THE WIND
AND WAVES ARE FORECAST TO DECREASE FRIDAY AND SATURDAY.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM SATURDAY TO 3 AM
SUNDAY.
&&
$$
000
FXUS63 KILX 070539
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1139 PM CST THU NOV 6 2008
.DISCUSSION...
ISSUED 858 PM CST THU NOV 6 2008
THE OCCLUDED FRONT AND BAND OF SHOWERS HAVE PUSHED EAST INTO
INDIANA...AND A CLEARING SLOT HAS OVERSPREAD OUR ENTIRE CWA. THE
DRY SLOT APPEARS TO BE ON THE STRONG SIDE...AND HAS WORKED TO
ERODE A FEW LINGERING BANDS OF CLOUDS NEAR THE COMMA HEAD.
FORECAST SOUNDINGS CONFIRM THE DRY LAYER IS SIGNIFICANT...
ESPECIALLY BETWEEN 800 MB AND 450 MB. I UPDATED THE CLOUD GRIDS TO
GO WITH MORE CLEARING FOR TONIGHT. WINDS WILL LIKELY KEEP TEMPS
FROM DROPPING OFF AS FAR AS THEY MIGHT IN THE DRY AIR AND CLEAR
SKIES. STILL...TEMPS WILL BE WELL BELOW WHAT WE HAVE SEEN THE LAST
WEEK OR SO.
THE WRAP AROUND MOISTURE IS EXPECTED TO ARRIVE TOMORROW...AND
SPRINKLES WILL BE POSSIBLE...ESPECIALLY IN THE AFTERNOON WHEN THE
MAIN PUSH OF MOISTURE TO THE SE OCCURS.
WILL SEND OUT SOME UPDATED ZONES AND GRIDS SHORTLY TO REMOVE THE
MENTION OF PRECIP TONIGHT.
SHIMON
&&
.AVIATION...
ISSUED 1139 PM CST THU NOV 6 2008...FOR THE 06Z TAFS
OUR CWA WILL BE UNDER THE INFLUENCE OF THE DRY SLOT FOR THE REST
OF THE NIGHT...EXCEPT FOR THE NW CORNER OF THE CWA. PIA MAY SEE
SOME 5K FT CLOUDS DRIFT BY FROM TIME TO TIME...BUT NO CIGS ARE
EXPECTED UNTIL FRIDAY MORNING AROUND 15Z. THE 00Z GUIDANCE IS
FOCUSING THE HIGHER CHANCES FOR PRECIP DURING THE AFTERNOON.
STILL...MEASURABLE PRECIP WILL BE HARD TO COME BY TOMORROW...SO
WILL STAY THE COURSE WITH VCSH IN THE TAFS THROUGH 00Z FRIDAY
EVENING. WILL KEEP A 4-5K FT CIG ALL DAY FRIDAY...WITH NO
RESTRICTION TO VIS. SOME FLAKES OF SNOW WILL NOT BE OUT OF THE
QUESTION...BUT NOT SIGNIFICANT. VCSH COVERS RAIN OR SNOW SHOWERS.
SOME LIGHT FOG IN CMI MAY LINGER FOR A FEW HOURS TONIGHT...BUT DO
NOT EXPECT ANY LOWER THAN 3 MILES. WILL KEEP PREVAILING 5SM
THROUGH MORNING.
SOUTHWEST WINDS WILL INCREASE TOMORROW AS THE PRESSURE GRADIENT
TIGHTENS NEAR THE SURFACE LOW. GUSTS MAY REACH NEAR 30 KTS AT
TIMES.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 258 PM CST THU NOV 6 2008
MAIN CONCERNS THIS PACKAGE INCLUDE ENDING OF PCPN THIS
EVENING...POTENTIAL OF ADDITIONAL PCPN AND PCPN TYPE THIS WEEKEND.
CONCERNS IN THE LONG TERM RELATE TO TIMING OF PCPN CHANCES MID WEEK.
MODELS DID FAIRLY GOOD JOB VERIFYING IN THE SHORT TERM BUT DIFFER
QUITE A BIT IN THE LONG TERM. A NAM-WRF/GFS BLEND LOOKS GOOD
THROUGH THE WEEKEND. IN THE LONG TERM...GFS IS QUICKER AND FURTHER
NORTH WITH THE NEXT EXPECTED SYSTEM COMING FROM THE SOUTHERN
PLAINS. ECMWF IS MUCH SLOWER. BOTH MODELS DO AGREE WITH SLOWING
THINGS DOWN BUT THEY ARE A GOOD 12HRS APART. FOR NOW WILL FOLLOW
HPC/CONSENSUS WHICH FAVORS CURRENT TREND IN GOING FORECAST.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
AREA WILL REMAIN IN CYCLONIC FLOW INTO THE WEEKEND AS THE SYSTEM
SLOWLY LIFTS INTO THE GREAT LAKES REGION. SHOWERS THAT ARE OVER
THE AREA AT THE MOMENT WILL PUSH EAST EARLY THIS EVENING AND WILL
JUST HAVE CHC POPS IN THE EAST FOR FIRST FEW HOURS ONLY. THEN DRY
WEATHER WILL MOVE IN FOR A PERIOD OF TIME. AS THE SYSTEM LIFTS
NORTHEAST LIGHT PCPN WILL BE POSSIBLE...JUST LIKE HAS BEEN
OCCURRING OUT WEST TODAY. PCPN TYPE WILL BEGIN AS LIQUID TOMORROW
WITH A POSSIBLE MIX IN THE NORTH. FRIDAY NIGHT AND SAT PCPN TYPE
COULD BE A MIX GIVEN THE FORECASTED SOUNDINGS AND CAA THAT WILL
BE OCCURRING INTO THE WEEKEND. THE SYSTEM WILL FINALLY LIFT OUT ON
SUNDAY CREATING A LOOSER GRADIENT AND DRY WEATHER. RIDGING WILL
ALSO BEGIN TO BUILD IN FOR SUNDAY NIGHT WITH LIGHT WINDS AND CLEAR
SKIES.
MET GUIDANCE APPEARS TOO COOL WHILE GFS APPEARS TOO WARM. OVERALL
FOLLOWED MET...BUT RAISED COUPLE OF DEGREES.
LONG TERM...MONDAY THROUGH THURSDAY
NEXT CHC OF PCPN WILL BE TOWARD MID WEEK. BELIEVE BEST CHC WILL
NOT BE UNTIL MONDAY NIGHT...BUT HAVE KEPT SLIGHT CHC FOR MONDAY
FOR NOW. SYSTEM WILL LIKELY STAY SOUTH OF THE AREA SPREADING PCPN
NORTH INTO OUR AREA. PCPN TYPE DURING THIS PERIOD SHOULD BE ALL
RAIN AS CLOUD COVER SHOULD KEEP TEMPS WARM ENOUGH THROUGH THE
PERIOD. OVERALL FLOW SEEMS WEAK SOUTHWESTERLY SO STORM TRACK
SHOULD REMAIN WEAK AND SOUTH. ANOTHER CHC OF PCPN IS POSSIBLE
THURSDAY BUT CONFIDENCE IS LOW AT THIS TIME.
TEMPS WILL REMAIN BELOW NORMAL DURING THE PERIOD AND MEX GUIDANCE
HAS PICKED UP ON THIS WELL. GUIDANCE DOES SHOW A WARMING TREND
LATER IN PERIOD BUT BELIEVE THIS IS TOO QUICK GIVEN SOUTHERLY
TRACK OF THE NEXT SYSTEM.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 070425
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1025 PM CST THU NOV 6 2008
.DISCUSSION...
656 PM CST
UPDATED GRIDS TO FINE TUNE THE ENDING OF THE PRECIP A BIT AND TO
LOWER SKY COVER OVERNIGHT AS LARGE DRY INTRUSION OVERSPREADS THE
CWA. STRATOCUMULUS ROTATING AROUND THE LARGE CYCLONE SHOULD BEGIN
TO FILTER BACK INTO THE AREA LATER TONIGHT BUT NOT BEFORE A PERIOD
OF RELATIVELY CLEAR SKIES. FIRST SURFACE TROUGH MOVING THROUGH
WILL ACT AS MORE OF A DRYLINE WITH TEMPS STILL RELATIVELY
MILD...THOUGH COLDER AIR SHOULD FILTER INTO THE AREA LATE TONIGHT
AND ESPECIALLY FRIDAY. SAW NO NEED TO ADJUST FORECAST LOWS AT THIS
TIME.
UPDATED GRIDS/TEXT PRODUCTS HAVE BEEN SENT.
IZZI
&&
.AVIATION...
1024 PM CST
06Z TAFORS...COLD FRONT SWINGING EAST ACROSS LAKE MICHIGAN AT 04Z
WITH STRONG DRYING CONTINUING TO SPREAD WEST TO EAST ACROSS
ILLINOIS. WITH MID AND UPPER LOW CENTERS ONLY MAKING VERY SLOW
EASTWARD PROGRESS ALONG THE MINNESOTA-IOWA BORDER OVERNIGHT PER
LATEST MODEL RUNS THE ASSOCIATED CLOUDINESS...THE EASTERN EXTEND
OF WHICH WAS ROTATING NORTH- NORTHEASTWARD ACROSS FAR NORTHWEST
ILLINOIS AND SOUTHWESTERN WISCONSIN...WILL ONLY JUST CLIP THE KRFD
AREA WHILE THE OTHER LOCAL TERMINALS REMAIN UNDER THE CLEAR SKY OF
THE DRY SLOT.
BY 080000 THE MID LEVEL LOW IS PROGGED TO BE OVER FAR SOUTHEAST
MINNESOTA/NORTHEAST IOWA/SOUTHWEST WISCONSIN WITH A TROUGH AXIS
ROTATING INTO NORTHWEST AND WEST CENTRAL ILLINOIS. SIGNIFICANT
LOW LEVEL COLD AIR ADVECTION WELL ALSO BE WELL UNDERWAY FROM IA
AND NORTHERN MO ACROSS IL AND SOUTHERN WI DURING THE DAY FRIDAY.
EXPECT THE MAIN STRATOCUMULUS DECK TO REACH THE LOCAL TERMINALS BY
MID FRIDAY MORNING WITH GRADUAL LOWERING WITH TIME AS THE STRONG
COLD AIR ADVECTION CONTINUES...THOUGH HAVE KEPT CEILINGS VFR
UNTIL LATER AFTERNOON AT KRFD AND UNTIL EVENING IN THE CHICAGO
AREA.
SHOWERS PRECEDING THE MID LEVEL TROUGH WILL BE APPROACHING FROM
THE WEST WITH TIME AND EXPECT THEM INTO KRFD FOR EARLY AFTERNOON
AND INTO CHICAGO TERMINALS BY EVENING...WITH OTHER SHOWERS NEAR/UNDER
THE MID LEVEL LOW SPREADING ACROSS NORTHERN ILLINOIS LATE AFTERNOON
AND FOR THE EVENING. GIVEN THAT THE FREEZING LEVEL IS SHOWN DOWN
TO AROUND 1000 FEET ABOVE GROUND LEVEL BY 071800 BY THE LATEST NAM
AND GFS MODEL RUNS HAVE PRECIPITATION AS MIXED RAIN AND SNOW
SHOWERS. ANY ADDITIONAL SNOW FLURRIES/SNOW SHOWERS NOT EXPECTED
INTO KORD UNTIL OVERNIGHT FRIDAY NIGHT/EARLY SATURDAY MORNING WHEN
THE MID LEVEL LOW WILL BE MOVING NORTHEASTWARD TO EAST CENTRAL
WISCONSIN.
TRS
&&
.MARINE...
200 PM CST
A LOW WAS WESTERN MINNESOTA THIS AFTERNOON. THIS LOW WILL MOVE INTO
NORTHWEST WISCONSIN BY FRIDAY AFTERNOON. THIS LOW WILL CAUSE STRONG
SOUTH WIND 15 TO 25 KNOTS OVER LAKE MICHIGAN TONIGHT. BY SATURDAY
AFTERNOON.THE LOW WILL BE OVER EASTERN ONTARIO. A HIGH WILL EXTEND
SOUTH FROM MANITOBA TO THE DAKOTA BY SATURDAY AFTERNOON. THE WIND
AND WAVES ARE FORECAST TO DECREASE FRIDAY AND SATURDAY.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
|
000
FXUS63 KILX 070258
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
858 PM CST THU NOV 6 2008
.DISCUSSION...
ISSUED 858 PM CST THU NOV 6 2008
THE OCCLUDED FRONT AND BAND OF SHOWERS HAVE PUSHED EAST INTO
INDIANA...AND A CLEARING SLOT HAS OVERSPREAD OUR ENTIRE CWA. THE
DRY SLOT APPEARS TO BE ON THE STRONG SIDE...AND HAS WORKED TO
ERODE A FEW LINGERING BANDS OF CLOUDS NEAR THE COMMA HEAD.
FORECAST SOUNDINGS CONFIRM THE DRY LAYER IS SIGNIFICANT...
ESPECIALLY BETWEEN 800 MB AND 450 MB. I UPDATED THE CLOUD GRIDS TO
GO WITH MORE CLEARING FOR TONIGHT. WINDS WILL LIKELY KEEP TEMPS
FROM DROPPING OFF AS FAR AS THEY MIGHT IN THE DRY AIR AND CLEAR
SKIES. STILL...TEMPS WILL BE WELL BELOW WHAT WE HAVE SEEN THE LAST
WEEK OR SO.
THE WRAP AROUND MOISTURE IS EXPECTED TO ARRIVE TOMORROW...AND
SPRINKLES WILL BE POSSIBLE...ESPECIALLY IN THE AFTERNOON WHEN THE
MAIN PUSH OF MOISTURE TO THE SE OCCURS.
WILL SEND OUT SOME UPDATED ZONES AND GRIDS SHORTLY TO REMOVE THE
MENTION OF PRECIP TONIGHT.
SHIMON
&&
.AVIATION...
ISSUED 548 PM CST THU NOV 6 2008...FOR THE 00Z TAFS
THE SHOWERS HAVE JUST MOVED EAST OF CMI. EXPECT AN IFR CIG TO LINGER
THROUGH 01Z...SO I PUT A TEMPO FOR THAT CONDITION. A DRY SLOT
WRAPPING IN BEHIND THE OCCLUDED FRONT IS PROVIDING A PERIOD OF MOSTLY
CLEAR SKIES AT THE OTHER SITES. THE COMMA HEAD OF CLOUDS IS NOT
FAR OFF TO THE WEST...AND PIA AND SPI SHOULD SEE A 5-6K FT CIG
BEFORE MIDNIGHT. THAT CIG WILL EVENTUALLY PROGRESS EASTWARD ACROSS
THE REMAINING TAF SITES BY FRIDAY MORNING.
PRECIP WILL BE MINIMAL UNTIL AFTERNOON. INITIALLY DID NOT INCLUDE
ANY VCSH...BUT WILL MOST LIKELY UPDATE TO ADD THAT FOR THE ENTIRE
DAY AFTER THE 5K-6K FT DECK OVERSPREADS ALL TAF SITES.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 258 PM CST THU NOV 6 2008
MAIN CONCERNS THIS PACKAGE INCLUDE ENDING OF PCPN THIS
EVENING...POTENTIAL OF ADDITIONAL PCPN AND PCPN TYPE THIS WEEKEND.
CONCERNS IN THE LONG TERM RELATE TO TIMING OF PCPN CHANCES MID WEEK.
MODELS DID FAIRLY GOOD JOB VERIFYING IN THE SHORT TERM BUT DIFFER
QUITE A BIT IN THE LONG TERM. A NAM-WRF/GFS BLEND LOOKS GOOD
THROUGH THE WEEKEND. IN THE LONG TERM...GFS IS QUICKER AND FURTHER
NORTH WITH THE NEXT EXPECTED SYSTEM COMING FROM THE SOUTHERN
PLAINS. ECMWF IS MUCH SLOWER. BOTH MODELS DO AGREE WITH SLOWING
THINGS DOWN BUT THEY ARE A GOOD 12HRS APART. FOR NOW WILL FOLLOW
HPC/CONSENSUS WHICH FAVORS CURRENT TREND IN GOING FORECAST.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
AREA WILL REMAIN IN CYCLONIC FLOW INTO THE WEEKEND AS THE SYSTEM
SLOWLY LIFTS INTO THE GREAT LAKES REGION. SHOWERS THAT ARE OVER
THE AREA AT THE MOMENT WILL PUSH EAST EARLY THIS EVENING AND WILL
JUST HAVE CHC POPS IN THE EAST FOR FIRST FEW HOURS ONLY. THEN DRY
WEATHER WILL MOVE IN FOR A PERIOD OF TIME. AS THE SYSTEM LIFTS
NORTHEAST LIGHT PCPN WILL BE POSSIBLE...JUST LIKE HAS BEEN
OCCURRING OUT WEST TODAY. PCPN TYPE WILL BEGIN AS LIQUID TOMORROW
WITH A POSSIBLE MIX IN THE NORTH. FRIDAY NIGHT AND SAT PCPN TYPE
COULD BE A MIX GIVEN THE FORECASTED SOUNDINGS AND CAA THAT WILL
BE OCCURRING INTO THE WEEKEND. THE SYSTEM WILL FINALLY LIFT OUT ON
SUNDAY CREATING A LOOSER GRADIENT AND DRY WEATHER. RIDGING WILL
ALSO BEGIN TO BUILD IN FOR SUNDAY NIGHT WITH LIGHT WINDS AND CLEAR
SKIES.
MET GUIDANCE APPEARS TOO COOL WHILE GFS APPEARS TOO WARM. OVERALL
FOLLOWED MET...BUT RAISED COUPLE OF DEGREES.
LONG TERM...MONDAY THROUGH THURSDAY
NEXT CHC OF PCPN WILL BE TOWARD MID WEEK. BELIEVE BEST CHC WILL
NOT BE UNTIL MONDAY NIGHT...BUT HAVE KEPT SLIGHT CHC FOR MONDAY
FOR NOW. SYSTEM WILL LIKELY STAY SOUTH OF THE AREA SPREADING PCPN
NORTH INTO OUR AREA. PCPN TYPE DURING THIS PERIOD SHOULD BE ALL
RAIN AS CLOUD COVER SHOULD KEEP TEMPS WARM ENOUGH THROUGH THE
PERIOD. OVERALL FLOW SEEMS WEAK SOUTHWESTERLY SO STORM TRACK
SHOULD REMAIN WEAK AND SOUTH. ANOTHER CHC OF PCPN IS POSSIBLE
THURSDAY BUT CONFIDENCE IS LOW AT THIS TIME.
TEMPS WILL REMAIN BELOW NORMAL DURING THE PERIOD AND MEX GUIDANCE
HAS PICKED UP ON THIS WELL. GUIDANCE DOES SHOW A WARMING TREND
LATER IN PERIOD BUT BELIEVE THIS IS TOO QUICK GIVEN SOUTHERLY
TRACK OF THE NEXT SYSTEM.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS63 KLOT 070058
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
658 PM CST THU NOV 6 2008
.DISCUSSION...
656 PM CST
UPDATED GRIDS TO FINE TUNE THE ENDING OF THE PRECIP A BIT AND TO
LOWER SKY COVER OVERNIGHT AS LARGE DRY INTRUSION OVERSPREADS THE
CWA. STRATOCUMULUS ROTATING AROUND THE LARGE CYCLONE SHOULD BEGIN
TO FILTER BACK INTO THE AREA LATER TONIGHT BUT NOT BEFORE A PERIOD
OF RELATIVELY CLEAR SKIES. FIRST SURFACE TROUGH MOVING THROUGH
WILL ACT AS MORE OF A DRYLINE WITH TEMPS STILL RELATIVELY
MILD...THOUGH COLDER AIR SHOULD FILTER INTO THE AREA LATE TONIGHT
AND ESPECIALLY FRIDAY. SAW NO NEED TO ADJUST FORECAST LOWS AT THIS
TIME.
UPDATED GRIDS/TEXT PRODUCTS HAVE BEEN SENT.
IZZI
&&
.PREV DISCUSSION...
311 PM CST
NOT MANY CHANGES MADE TO THE GOING SHORT TERM FORECAST WITH THE
ONLY MODIFICATIONS MADE TO BETTER TIME THE END OF PRECIP TONIGHT
AND THE START UP OF PRECIP TOMORROW AFTERNOON AFTER THE DRY SLOT
MOVES THROUGH.
COLD FRONT CURRENTLY WORKING ITS WAY THROUGH NORTHERN ILLINOIS
SHOULD CLEAR THE FORECAST AREA IN NW INDIANA BY 3Z TONIGHT. ANY
CHANCE FOR STORMS SEEMS TO BE RATHER MINIMAL AT THIS POINT WITH
MAINLY JUST SCATTERED SHOWERS GATHERING OUT AHEAD OF THE COLD
FRONT. TEMPERATURES WILL NOT BE DRASTICALLY DROPPING AS THIS COLD
FRONT PASSES...BUT RATHER BE A GRADUAL DECLINE BACK DOWN TO WHAT THE
NORM OVERNIGHT INTO FRIDAY MORNING AS THE COLD TONGUE OF AIR WRAPS
AROUND THE SOUTHERN PERIPHERY OF THE STACKED LOW. AFTER A VERY
BRIEF WINDOW OF CLEAR SKIES IN THE DRY SLOT...CLOUDS WILL MOVE
BACK IN AS THE CORE OF THE LOW MOVES INTO THE REGION. THE FIRST
SHOWERS SHOULD COME BACK INTO NORTHERN ILLINOIS ON FRIDAY
AFTERNOON AND TRACK SLOWLY FROM WEST TO EAST. LOW LEVEL
TEMPERATURE PROFILES AND 1000-850MB THICKNESSES SUGGEST THAT THE
PRECIP WILL LIKELY START OUT AS RAIN SHOWERS AND THEN TRANSITION
TO A MIX OF RAIN AND SNOW SHOWERS LATER IN THE AFTERNOON AS THE
WINDS SLIGHTLY VEER MORE WESTERLY. PRECIP SHOULD CHANGE ALL OVER
TO SNOW LATE IN THE EVENING FRIDAY INTO SATURDAY MORNING. WITH SFC
SOIL TEMPS UP IN THE 50S IT WILL BE DIFFICULT FOR THESE SNOW
SHOWERS TO ACCUMULATE AT ALL OUTSIDE OF GRASSY AREAS AND SNOW
BOARDS. TOSSED IN A TENTH OF AN INCH OF ACCUMULATION IN THE
GRIDS...MAINLY NORTH OF I-80 FOR EARLY SATURDAY MORNING WHERE THE
SNOW SHOWERS MAY BE MORE PERSISTENT. WITH THE LOW LEVELS OF THE
ATMOSPHERE REMAINING SLIGHTLY UNSTABLE AND MAINLY BELOW FREEZING
INTO SUNDAY...WILL STILL HAVE A CHANCE FOR SOME SCATTERED FLURRIES
UNTIL THE CLOSED LOW SYSTEM MOVES INTO CANADA.
WITH THE STACKED LOW PROPAGATING THROUGH EASTERN CANADA AND THE
UPPER LEVEL JET DIVING DOWN ACROSS THE SOUTHERN US...OUR REGION
WILL REMAIN STUCK IN SPLIT FLOW WITH HIGH PRESSURE BUILDING IN AT
THE SURFACE. THE BIGGEST QUESTION MARK OF THE EXTENDED PERIOD
LINGERS WITH THE SOUTHERN STREAM SYSTEM ON TUESDAY THAT HAS BEEN
FLIPPED AND FLOPPED BACK AND FORTH BY THE GFS AND ECMWF THE PAST
FEW DAYS. PREVIOUSLY...THESE MODELS WERE KEEPING THE SYSTEM WELL
TO THE SOUTH OR PUSHED BACK TO LATER IN THE WEEK. HOWEVER...WITH
TODAYS 12Z RUNS THEY BOTH SEEM TO BE COMING TO MORE OF A CONSENSUS
WITH THE PRECIP SHIELD FROM THIS SYSTEM TAGGING THE FORECAST AREA.
THE GENERAL TRACK THAT THE 12Z GFS TAKES WITH THE LOW MOVING
THROUGH THE OHIO RIVER VALLEY REGION WILL NEED TO BEAR WATCHING AS
THIS IS TYPICALLY A FAVORABLE TRACK TO AT LEAST GET THE NORTHERN
EDGE OF A WINTER SYSTEM. WHILE THE PLACEMENT OF THE SFC RIDGE IS
NOT IN THE BEST POSITION TO KEEP THE COLD AIR IN PLACE...IT DOES
SEEM PLAUSIBLE VIA THIS SOLUTION TO SEE OUR FIRST ACCUMULATION OF
SNOW/SLEET ALONG THE NORTHWEST PORTION OF THE PRECIP. THE 12Z
ECMWF IS TRENDING TOWARD THIS SOLUTION AND DOES HAVE BETTER...IF
YOU WANT SNOW...PLACEMENT OF THE SFC RIDGE TO KEEP THE COLD AIR IN
PLACE. CERTAINLY HAVE VERY LOW CONFIDENCE IN THIS PORTION OF THE
FORECAST PERIOD GIVEN THE EXTREME CHANGES IN MODEL RUNS THE PAST
FEW DAYS...BUT THE TREND WILL BE WORTH WATCHING. IN THE
MEANTIME...ADDED A MENTION OF POPS IN THE SOUTHERN PORTION OF THE
CWA TO AT LEAST START HIGHLIGHTING THIS PRECIP.
HALBACH
&&
.AVIATION...
548 PM CST
00Z TAFORS...COLD FRONT HAD REACHED THE WESTERN SHORE OF LAKE MI
AT 23Z WITH WIND AT KORD AND KMDW VEERING FROM SLIGHTLY EAST OF
SOUTH TO SLIGHTLY WEST OF SOUTH. DRYING WAS RAPIDLY SPREADING INTO
WEST CENTRAL AND FAR NORTHWEST IL WITH DEW POINTS DROPPING FROM
MID AND UPPER 50S TO MID AND UPPER 30S DURING THE AFTERNOON.
WITH THE PASSAGE OF THE FRONT AND THE IMPRESSIVE DRYING THE LAST
OF THE SHOWERS WILL BE EXITING FAR NORTHEAST IL BY 01Z AND KGYY
AROUND 02Z ALONG WITH RAPID RAISING OF CEILINGS TO VFR...FOLLOWED
SOON THEREAFTER BY CLEARING AS THE DRY SLOT SLIPS A LITTLE FURTHER
TO THE EAST AND OVER ALL THE LOCAL TERMINALS DURING THE EVENING.
WITH MID AND UPPER LOW CENTERS ONLY MAKING MINOR EASTWARD PROGRESS
DURING THE NIGHT PER THE MODELS THE ASSOCIATED CLOUDINESS...WHICH
WAS CURRENTLY JUST WEST OF THE MS RIVER...WILL ONLY PUSH AS FAR
EAST AS NORTHWEST AND WEST CENTRAL IL BEFORE DAWN. BY 080000 THE
UPPER LOW IS PROGGED TO BE OVER FAR SOUTHEAST WI WITH SIGNIFICANT
LOW LEVEL COLD AIR ADVECTION OCCURRING FROM IA AND NORTHERN MO
ACROSS IL AND SOUTHERN WI.
EXPECT THE STRATOCUMULUS DECK TO REACH THE LOCAL TERMINALS BY
LATER FRIDAY MORNING...AND LOWERING WITH TIME AS THE STRONG COLD
AIR ADVECTION CONTINUES THOUGH HAVE KEPT CEILINGS VFR. SHOWERS
CLOSE TO/UNDER THE UPPER LOW WILL ALSO BE APPROACHING FROM THE
WEST WITH TIME AND WILL BE REACHING KRFD BY LATER AFTERNOON AND
THE CHICAGO AREA BY EARLY EVENING. FOR KORD HAVE WENT WITH A
CHANCE OF SNOW SHOWERS DURING THE EVENING GIVEN THE FREEZING LEVEL
IS SHOWN DOWN TO 1000-1500 FEET ABOVE GROUND LEVEL BY 080000 BY
NAM AND GFS MODELS. MAY START AS LIQUID OR MIXED BUT FREEZING
LEVEL CONTINUES TO LOWER DURING THE EVENING AND EXPECT TO TURN TO
ALL SNOW.
TRS
&&
.MARINE...
200 PM CST
A LOW WAS WESTERN MINNESOTA THIS AFTERNOON. THIS LOW WILL MOVE INTO
NORTHWEST WISCONSIN BY FRIDAY AFTERNOON. THIS LOW WILL CAUSE STRONG
SOUTH WIND 15 TO 25 KNOTS OVER LAKE MICHIGAN TONIGHT. BY SATURDAY
AFTERNOON.THE LOW WILL BE OVER EASTERN ONTARIO. A HIGH WILL EXTEND
SOUTH FROM MANITOBA TO THE DAKOTA BY SATURDAY AFTERNOON. THE WIND
AND WAVES ARE FORECAST TO DECREASE FRIDAY AND SATURDAY.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM THURSDAY.
&&
$$
000
FXUS63 KLOT 062352
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
552 PM CST THU NOV 6 2008
.DISCUSSION...
311 PM CST
NOT MANY CHANGES MADE TO THE GOING SHORT TERM FORECAST WITH THE
ONLY MODIFICATIONS MADE TO BETTER TIME THE END OF PRECIP TONIGHT
AND THE START UP OF PRECIP TOMORROW AFTERNOON AFTER THE DRY SLOT
MOVES THROUGH.
COLD FRONT CURRENTLY WORKING ITS WAY THROUGH NORTHERN ILLINOIS
SHOULD CLEAR THE FORECAST AREA IN NW INDIANA BY 3Z TONIGHT. ANY
CHANCE FOR STORMS SEEMS TO BE RATHER MINIMAL AT THIS POINT WITH
MAINLY JUST SCATTERED SHOWERS GATHERING OUT AHEAD OF THE COLD
FRONT. TEMPERATURES WILL NOT BE DRASTICALLY DROPPING AS THIS COLD
FRONT PASSES...BUT RATHER BE A GRADUAL DECLINE BACK DOWN TO WHAT THE
NORM OVERNIGHT INTO FRIDAY MORNING AS THE COLD TONGUE OF AIR WRAPS
AROUND THE SOUTHERN PERIPHERY OF THE STACKED LOW. AFTER A VERY
BRIEF WINDOW OF CLEAR SKIES IN THE DRY SLOT...CLOUDS WILL MOVE
BACK IN AS THE CORE OF THE LOW MOVES INTO THE REGION. THE FIRST
SHOWERS SHOULD COME BACK INTO NORTHERN ILLINOIS ON FRIDAY
AFTERNOON AND TRACK SLOWLY FROM WEST TO EAST. LOW LEVEL
TEMPERATURE PROFILES AND 1000-850MB THICKNESSES SUGGEST THAT THE
PRECIP WILL LIKELY START OUT AS RAIN SHOWERS AND THEN TRANSITION
TO A MIX OF RAIN AND SNOW SHOWERS LATER IN THE AFTERNOON AS THE
WINDS SLIGHTLY VEER MORE WESTERLY. PRECIP SHOULD CHANGE ALL OVER
TO SNOW LATE IN THE EVENING FRIDAY INTO SATURDAY MORNING. WITH SFC
SOIL TEMPS UP IN THE 50S IT WILL BE DIFFICULT FOR THESE SNOW
SHOWERS TO ACCUMULATE AT ALL OUTSIDE OF GRASSY AREAS AND SNOW
BOARDS. TOSSED IN A TENTH OF AN INCH OF ACCUMULATION IN THE
GRIDS...MAINLY NORTH OF I-80 FOR EARLY SATURDAY MORNING WHERE THE
SNOW SHOWERS MAY BE MORE PERSISTENT. WITH THE LOW LEVELS OF THE
ATMOSPHERE REMAINING SLIGHTLY UNSTABLE AND MAINLY BELOW FREEZING
INTO SUNDAY...WILL STILL HAVE A CHANCE FOR SOME SCATTERED FLURRIES
UNTIL THE CLOSED LOW SYSTEM MOVES INTO CANADA.
WITH THE STACKED LOW PROPAGATING THROUGH EASTERN CANADA AND THE
UPPER LEVEL JET DIVING DOWN ACROSS THE SOUTHERN US...OUR REGION
WILL REMAIN STUCK IN SPLIT FLOW WITH HIGH PRESSURE BUILDING IN AT
THE SURFACE. THE BIGGEST QUESTION MARK OF THE EXTENDED PERIOD
LINGERS WITH THE SOUTHERN STREAM SYSTEM ON TUESDAY THAT HAS BEEN
FLIPPED AND FLOPPED BACK AND FORTH BY THE GFS AND ECMWF THE PAST
FEW DAYS. PREVIOUSLY...THESE MODELS WERE KEEPING THE SYSTEM WELL
TO THE SOUTH OR PUSHED BACK TO LATER IN THE WEEK. HOWEVER...WITH
TODAYS 12Z RUNS THEY BOTH SEEM TO BE COMING TO MORE OF A CONSENSUS
WITH THE PRECIP SHIELD FROM THIS SYSTEM TAGGING THE FORECAST AREA.
THE GENERAL TRACK THAT THE 12Z GFS TAKES WITH THE LOW MOVING
THROUGH THE OHIO RIVER VALLEY REGION WILL NEED TO BEAR WATCHING AS
THIS IS TYPICALLY A FAVORABLE TRACK TO AT LEAST GET THE NORTHERN
EDGE OF A WINTER SYSTEM. WHILE THE PLACEMENT OF THE SFC RIDGE IS
NOT IN THE BEST POSITION TO KEEP THE COLD AIR IN PLACE...IT DOES
SEEM PLAUSIBLE VIA THIS SOLUTION TO SEE OUR FIRST ACCUMULATION OF
SNOW/SLEET ALONG THE NORTHWEST PORTION OF THE PRECIP. THE 12Z
ECMWF IS TRENDING TOWARD THIS SOLUTION AND DOES HAVE BETTER...IF
YOU WANT SNOW...PLACEMENT OF THE SFC RIDGE TO KEEP THE COLD AIR IN
PLACE. CERTAINLY HAVE VERY LOW CONFIDENCE IN THIS PORTION OF THE
FORECAST PERIOD GIVEN THE EXTREME CHANGES IN MODEL RUNS THE PAST
FEW DAYS...BUT THE TREND WILL BE WORTH WATCHING. IN THE
MEANTIME...ADDED A MENTION OF POPS IN THE SOUTHERN PORTION OF THE
CWA TO AT LEAST START HIGHLIGHTING THIS PRECIP.
HALBACH
&&
.AVIATION...
548 PM CST
00Z TAFORS...COLD FRONT HAD REACHED THE WESTERN SHORE OF LAKE MI
AT 23Z WITH WIND AT KORD AND KMDW VEERING FROM SLIGHTLY EAST OF
SOUTH TO SLIGHTLY WEST OF SOUTH. DRYING WAS RAPIDLY SPREADING INTO
WEST CENTRAL AND FAR NORTHWEST IL WITH DEW POINTS DROPPING FROM
MID AND UPPER 50S TO MID AND UPPER 30S DURING THE AFTERNOON.
WITH THE PASSAGE OF THE FRONT AND THE IMPRESSIVE DRYING THE LAST
OF THE SHOWERS WILL BE EXITING FAR NORTHEAST IL BY 01Z AND KGYY
AROUND 02Z ALONG WITH RAPID RAISING OF CEILINGS TO VFR...FOLLOWED
SOON THEREAFTER BY CLEARING AS THE DRY SLOT SLIPS A LITTLE FURTHER
TO THE EAST AND OVER ALL THE LOCAL TERMINALS DURING THE EVENING.
WITH MID AND UPPER LOW CENTERS ONLY MAKING MINOR EASTWARD PROGRESS
DURING THE NIGHT PER THE MODELS THE ASSOCIATED CLOUDINESS...WHICH
WAS CURRENTLY JUST WEST OF THE MS RIVER...WILL ONLY PUSH AS FAR
EAST AS NORTHWEST AND WEST CENTRAL IL BEFORE DAWN. BY 080000 THE
UPPER LOW IS PROGGED TO BE OVER FAR SOUTHEAST WI WITH SIGNIFICANT
LOW LEVEL COLD AIR ADVECTION OCCURRING FROM IA AND NORTHERN MO
ACROSS IL AND SOUTHERN WI.
EXPECT THE STRATOCUMULUS DECK TO REACH THE LOCAL TERMINALS BY
LATER FRIDAY MORNING...AND LOWERING WITH TIME AS THE STRONG COLD
AIR ADVECTION CONTINUES THOUGH HAVE KEPT CEILINGS VFR. SHOWERS
CLOSE TO/UNDER THE UPPER LOW WILL ALSO BE APPROACHING FROM THE
WEST WITH TIME AND WILL BE REACHING KRFD BY LATER AFTERNOON AND
THE CHICAGO AREA BY EARLY EVENING. FOR KORD HAVE WENT WITH A
CHANCE OF SNOW SHOWERS DURING THE EVENING GIVEN THE FREEZING LEVEL
IS SHOWN DOWN TO 1000-1500 FEET ABOVE GROUND LEVEL BY 080000 BY
NAM AND GFS MODELS. MAY START AS LIQUID OR MIXED BUT FREEZING
LEVEL CONTINUES TO LOWER DURING THE EVENING AND EXPECT TO TURN TO
ALL SNOW.
TRS
&&
.MARINE...
200 PM CST
A LOW WAS WESTERN MINNESOTA THIS AFTERNOON. THIS LOW WILL MOVE INTO
NORTHWEST WISCONSIN BY FRIDAY AFTERNOON. THIS LOW WILL CAUSE STRONG
SOUTH WIND 15 TO 25 KNOTS OVER LAKE MICHIGAN TONIGHT. BY SATURDAY
AFTERNOON.THE LOW WILL BE OVER EASTERN ONTARIO. A HIGH WILL EXTEND
SOUTH FROM MANITOBA TO THE DAKOTA BY SATURDAY AFTERNOON. THE WIND
AND WAVES ARE FORECAST TO DECREASE FRIDAY AND SATURDAY.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM THURSDAY.
&&
$$
000
FXUS63 KILX 062348
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
548 PM CST THU NOV 6 2008
.DISCUSSION...
ISSUED 258 PM CST THU NOV 6 2008
MAIN CONCERNS THIS PACKAGE INCLUDE ENDING OF PCPN THIS
EVENING...POTENTIAL OF ADDITIONAL PCPN AND PCPN TYPE THIS WEEKEND.
CONCERNS IN THE LONG TERM RELATE TO TIMING OF PCPN CHANCES MID WEEK.
MODELS DID FAIRLY GOOD JOB VERIFYING IN THE SHORT TERM BUT DIFFER
QUITE A BIT IN THE LONG TERM. A NAM-WRF/GFS BLEND LOOKS GOOD
THROUGH THE WEEKEND. IN THE LONG TERM...GFS IS QUICKER AND FURTHER
NORTH WITH THE NEXT EXPECTED SYSTEM COMING FROM THE SOUTHERN
PLAINS. ECMWF IS MUCH SLOWER. BOTH MODELS DO AGREE WITH SLOWING
THINGS DOWN BUT THEY ARE A GOOD 12HRS APART. FOR NOW WILL FOLLOW
HPC/CONSENSUS WHICH FAVORS CURRENT TREND IN GOING FORECAST.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
AREA WILL REMAIN IN CYCLONIC FLOW INTO THE WEEKEND AS THE SYSTEM
SLOWLY LIFTS INTO THE GREAT LAKES REGION. SHOWERS THAT ARE OVER
THE AREA AT THE MOMENT WILL PUSH EAST EARLY THIS EVENING AND WILL
JUST HAVE CHC POPS IN THE EAST FOR FIRST FEW HOURS ONLY. THEN DRY
WEATHER WILL MOVE IN FOR A PERIOD OF TIME. AS THE SYSTEM LIFTS
NORTHEAST LIGHT PCPN WILL BE POSSIBLE...JUST LIKE HAS BEEN
OCCURRING OUT WEST TODAY. PCPN TYPE WILL BEGIN AS LIQUID TOMORROW
WITH A POSSIBLE MIX IN THE NORTH. FRIDAY NIGHT AND SAT PCPN TYPE
COULD BE A MIX GIVEN THE FORECASTED SOUNDINGS AND CAA THAT WILL
BE OCCURRING INTO THE WEEKEND. THE SYSTEM WILL FINALLY LIFT OUT ON
SUNDAY CREATING A LOOSER GRADIENT AND DRY WEATHER. RIDGING WILL
ALSO BEGIN TO BUILD IN FOR SUNDAY NIGHT WITH LIGHT WINDS AND CLEAR
SKIES.
MET GUIDANCE APPEARS TOO COOL WHILE GFS APPEARS TOO WARM. OVERALL
FOLLOWED MET...BUT RAISED COUPLE OF DEGREES.
LONG TERM...MONDAY THROUGH THURSDAY
NEXT CHC OF PCPN WILL BE TOWARD MID WEEK. BELIEVE BEST CHC WILL
NOT BE UNTIL MONDAY NIGHT...BUT HAVE KEPT SLIGHT CHC FOR MONDAY
FOR NOW. SYSTEM WILL LIKELY STAY SOUTH OF THE AREA SPREADING PCPN
NORTH INTO OUR AREA. PCPN TYPE DURING THIS PERIOD SHOULD BE ALL
RAIN AS CLOUD COVER SHOULD KEEP TEMPS WARM ENOUGH THROUGH THE
PERIOD. OVERALL FLOW SEEMS WEAK SOUTHWESTERLY SO STORM TRACK
SHOULD REMAIN WEAK AND SOUTH. ANOTHER CHC OF PCPN IS POSSIBLE
THURSDAY BUT CONFIDENCE IS LOW AT THIS TIME.
TEMPS WILL REMAIN BELOW NORMAL DURING THE PERIOD AND MEX GUIDANCE
HAS PICKED UP ON THIS WELL. GUIDANCE DOES SHOW A WARMING TREND
LATER IN PERIOD BUT BELIEVE THIS IS TOO QUICK GIVEN SOUTHERLY
TRACK OF THE NEXT SYSTEM.
AUTEN
&&
.AVIATION...
ISSUED 548 PM CST THU NOV 6 2008...FOR THE 00Z TAFS
THE SHOWERS HAVE JUST MOVED EAST OF CMI. EXPECT AN IFR CIG TO LINGER
THROUGH 01Z...SO I PUT A TEMPO FOR THAT CONDITION. A DRY SLOT
WRAPPING IN BEHIND THE OCCLUDED FRONT IS PROVIDING A PERIOD OF MOSTLY
CLEAR SKIES AT THE OTHER SITES. THE COMMA HEAD OF CLOUDS IS NOT
FAR OFF TO THE WEST...AND PIA AND SPI SHOULD SEE A 5-6K FT CIG
BEFORE MIDNIGHT. THAT CIG WILL EVENTUALLY PROGRESS EASTWARD ACROSS
THE REMAINING TAF SITES BY FRIDAY MORNING.
PRECIP WILL BE MINIMAL UNTIL AFTERNOON. INITIALLY DID NOT INCLUDE
ANY VCSH...BUT WILL MOST LIKELY UPDATE TO ADD THAT FOR THE ENTIRE
DAY AFTER THE 5K-6K FT DECK OVERSPREADS ALL TAF SITES.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
| 
