Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 12/04/11
AREA FORECAST DISCUSSION...CORRECTION
NWS GRAND JUNCTION CO
308 PM MST FRI DEC 2 2011
CORRECTED SHORT TERM TIME PERIOD DESCRIPTOR
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
THE CLOSED LOW OVER AZ FINALLY BEGINNING TO OPEN UP AND IS EXPECTED
TO EJECT THROUGH NM AND THE 4 CORNERS TONIGHT AS THE NEXT TROUGH
DIVES DOWN TO REPLACE IT. MOISTURE HAS SPREAD ACROSS MUCH SE UT AND
WRN CO TODAY AND NICELY CAPTURED ON THE 300K POTENTIAL TEMP
SURFACE...WITH LIGHT SNOW REPORTED OVER HIGHER TERRAIN FROM MOUNT
WERNER ABOVE STEAMBOAT SPGS TO GRAND MESA TO THE SAN JUAN MTNS. SNOW
ALSO ALONG THE SRN BASE OF THE SAN JUANS FROM CORTEZ TO PAGOSA IN THE
UPSLOPE FLOW. RUC MODELS SHOWS A COUPLE WAVES OF ENERGY MOVING UP
FROM THE LOW...SO EXPECT SNOW INTENSITY TO VARY THROUGH THE NIGHT
IN SW CO. CURRENT WINTER HIGHLIGHTS FOR THE SAN JUAN/ABAJO/LA SAL
MTNS AND THE DURANGO-PAGOSA AREA LOOK ON TRACK.
THE SECOND SPLITTING TROUGH WAS DROPPING ACROSS ID AND DRIVEN BY A
120 KT UPPER JET OVER THE PAC NW. THIS TROUGH EXPECTED TO PUSH A COLD
FRONT INTO NE UT/NW CO TONIGHT AND THEN INTO SE UT/SW CO SAT AS IT
FORMS A SECOND CLOSED OVER AZ. RATHER NARROW BAND OF MOISTURE
ASSOCIATED WITH THE TROUGH MOVING INTO NW UT...BUT EXPECT SNOW
COVERAGE TO INCREASE OVER NE UT/NW CO TONIGHT AS THE FRONT
INTERACTS WITH THE MOISTURE IN PLACE AHEAD OF THE AZ LOW. THE FRONT
EXPECTED TO SLOW ACROSS THE N LATE TONIGHT...AND A PERIOD DECENT
NORTHEAST OROGRAPHIC WINDS COMBINED WITH COLD ADVECTION SHOULD BRING
3-6 INCHES OF SNOW TO THE ERN UINTA MTNS...ESPECIALLY THEIR NORTH
SLOPES. BUT...NORTHEAST WINDS NOT AS STRONG OR AS LONG IN DURATION
AS THE STORM WED NIGHT...SO REFRAINED FROM ANY HIGHLIGHT FOR THE ERN
UINTAS AT THIS TIME. A PERIOD OF GUSTY NE WINDS LIKELY ACROSS NW CO
SAT MORNING AS WELL...BUT AGAIN NOT NEARLY AS STRONG AS WHAT OCCURRED
THU MORNING.
BOTH NAM AND GFS INDICATE A WEAK 700 MB LOW FORMS OVER WRN CO
TONIGHT/SAT MORNING. BANKING ON ENHANCED LOW LEVEL CONVERGENCE
AND EVENTUAL FRONTAL PASSAGE TO ENHANCE SNOWFALL FROM GRAND MESA TO
THE WEST ELKS. WEST ELKS SHOULD ALSO BENEFIT FROM SOME MOIST
SOUTHERLY OROGRAPHIC FLOW TONIGHT...WHILE TRAILING NORTHERLY FLOW MAY
KEEP SOME LIGHT SNOW OVER GRAND MESA INTO SAT EVENING. AS SUCH...
ELECTED TO INCLUDE THE GRAND MESA AND WEST ELKS /ZONES 9 AND 12/ IN A
LOW-END ADVISORY TONIGHT INTO SAT EVENING FOR 4 TO 9 INCHES OF
SNOW. THE 700 MB LOW SHOULD ALSO BRING SNOW TO MANY CENTRAL VALLEYS
BUT WITH LITTLE ACCUMS EXPECTED.
SNOW DIMINISHES SAT NIGHT WITH CLEARING FROM THE NW. ERN UT/WRN CO
SHOULD BE IN BETWEEN SYSTEMS SUNDAY AS MODELS SHOW YET A THIRD
SPLITTING TROUGH APPROACHING FROM THE N LATE IN THE WEEKEND. WILL
TREND THE CHANCE OF PRECIP UP AGAIN ACROSS THE NORTHERN MTNS SUNDAY
AFTERNOON AS A RESULT.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE EARLY PART OF THE LONG TERM IS A CONTINUATION OF A REPEATING
PATTERN THAT HAS BEEN IN CONTROL SINCE THIS MIDWEEK. THE LAST OF A
SERIES OF SHORTWAVES WILL DROP SOUTHWARD INTO ARIZONA AND AGAIN FORM
A LOW TO OUR SOUTHWEST SUNDAY NIGHT INTO MONDAY. TODAY`S RUNS ARE
FARTHER WEST THAN YESTERDAY`S...WHICH DOES NOT ALLOW THE BEST
MOISTURE/DYNAMICS/OROGRAPHICS TO MOVE OVER OUR FORECAST AREA. THAT
SAID...THIS DISTURBANCE WILL BE IN CLOSE ENOUGH PROXIMITY FOR ANOTHER
ROUND OF MOUNTAIN SNOWFALL...WITH A CHANCE OF SNOW IN MANY VALLEYS.
THE FAVORED AREA WILL SWITCH FROM THE NORTH TO THE SOUTH LATE SUNDAY
NIGHT...WITH CLEARING OVER THE NORTH DURING THE DAY ON MONDAY. WINDS
DO NOT SEEM TO BE AS STRONG AS YESTERDAY`S SYSTEM...SO DO NOT
ANTICIPATE NEARLY AS MUCH BLOWING SNOW.
WE CONTINUE TO SEE SOME DISCREPANCIES IN RUN-TO-RUN AND BETWEEN-MODEL
SOLUTIONS FOR THE UPCOMING LONG TERM PERIOD. TODAY`S RUNS KEEP THE
AREA DRY THROUGH THE REMAINDER OF THE PERIOD. WE SIT UNDER A DRY AND
COLD NORTHWEST FLOW AS HIGH PRESSURE DOMINATES THE WEST COAST THROUGH
THE GREAT BASIN. THIS PATTERN IS NOW PROGGED TO PERSIST THROUGH THE
WORK WEEK. MODELS INDICATE THAT THERE MAY BE A COUPLE WEAK WAVES THAT
BRUSH THE NORTHERN EDGE...BUT THE TIMING AND TRACK IS BOUND TO CHANGE
WITH FUTURE MODEL RUNS.
TEMPERATURES WILL BE BELOW NORMAL IN THE DRY AIR MASS...ESPECIALLY AT
NIGHT. SOME MODIFICATION IS EXPECTED TOWARDS THE END OF THE PERIOD.
ANY WAVES THAT BRUSH THE AREA WILL ACT TO MODIFY TEMPS...AGAIN MAINLY
AT NIGHT.
&&
.AVIATION /FOR 00Z TAF ISSUANCE/...
SNOW HAS DEVELOPED OVER MANY MOUNTAIN AREAS AND IN SOME SOUTHERN
VALLEYS THIS AFTERNOON. THIS ACTIVITY IS EXPECTED TO BECOME MORE
WIDESPREAD THIS EVENING AND OVERNIGHT. THEREFORE MVFR/IFR VIS/CIGS IS
EXPECTED MUCH OF THE TIME OVER THE MOUNTAINS...AND FOR SHORTER
PERIODS IN THE VALLEYS. BY MIDNIGHT ALL TAF SITES WILL HAVE A CHANCE
OF MVFR/IFR AS THE CHANCE FOR PRECIPITATION SPREADS INTO THE LOWER
VALLEYS. SNOW AND LOW CLOUDS WILL CONTINUE...DIMINISHING FROM THE
NORTH DURING THE AFTERNOON. THEREFORE PERIODS OF MVFR/IFR ARE
EXPECTED THROUGH THE DAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONES
9/12/18.
WINTER STORM WARNING UNTIL 11 PM MST SATURDAY FOR ZONE 019.
WINTER WEATHER ADVISORY UNTIL 2 PM MST SATURDAY FOR ZONES 22/23.
UT...WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONE 28.
&&
$$
SHORT TERM...JAD
LONG TERM....EH
AVIATION.....EH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
305 PM MST FRI DEC 2 2011
.SHORT TERM /TODAY THROUGH SATURDAY NIGHT/...
THE CLOSED LOW OVER AZ FINALLY BEGINNING TO OPEN UP AND IS EXPECTED
TO EJECT THROUGH NM AND THE 4 CORNERS TONIGHT AS THE NEXT TROUGH
DIVES DOWN TO REPLACE IT. MOISTURE HAS SPREAD ACROSS MUCH SE UT AND
WRN CO TODAY AND NICELY CAPTURED ON THE 300K POTENTIAL TEMP
SURFACE...WITH LIGHT SNOW REPORTED OVER HIGHER TERRAIN FROM MOUNT
WERNER ABOVE STEAMBOAT SPGS TO GRAND MESA TO THE SAN JUAN MTNS. SNOW
ALSO ALONG THE SRN BASE OF THE SAN JUANS FROM CORTEZ TO PAGOSA IN THE
UPSLOPE FLOW. RUC MODELS SHOWS A COUPLE WAVES OF ENERGY MOVING UP
FROM THE LOW...SO EXPECT SNOW INTENSITY TO VARY THROUGH THE NIGHT
IN SW CO. CURRENT WINTER HIGHLIGHTS FOR THE SAN JUAN/ABAJO/LA SAL
MTNS AND THE DURANGO-PAGOSA AREA LOOK ON TRACK.
THE SECOND SPLITTING TROUGH WAS DROPPING ACROSS ID AND DRIVEN BY A
120 KT UPPER JET OVER THE PAC NW. THIS TROUGH EXPECTED TO PUSH A COLD
FRONT INTO NE UT/NW CO TONIGHT AND THEN INTO SE UT/SW CO SAT AS IT
FORMS A SECOND CLOSED OVER AZ. RATHER NARROW BAND OF MOISTURE
ASSOCIATED WITH THE TROUGH MOVING INTO NW UT...BUT EXPECT SNOW
COVERAGE TO INCREASE OVER NE UT/NW CO TONIGHT AS THE FRONT
INTERACTS WITH THE MOISTURE IN PLACE AHEAD OF THE AZ LOW. THE FRONT
EXPECTED TO SLOW ACROSS THE N LATE TONIGHT...AND A PERIOD DECENT
NORTHEAST OROGRAPHIC WINDS COMBINED WITH COLD ADVECTION SHOULD BRING
3-6 INCHES OF SNOW TO THE ERN UINTA MTNS...ESPECIALLY THEIR NORTH
SLOPES. BUT...NORTHEAST WINDS NOT AS STRONG OR AS LONG IN DURATION
AS THE STORM WED NIGHT...SO REFRAINED FROM ANY HIGHLIGHT FOR THE ERN
UINTAS AT THIS TIME. A PERIOD OF GUSTY NE WINDS LIKELY ACROSS NW CO
SAT MORNING AS WELL...BUT AGAIN NOT NEARLY AS STRONG AS WHAT OCCURRED
THU MORNING.
BOTH NAM AND GFS INDICATE A WEAK 700 MB LOW FORMS OVER WRN CO
TONIGHT/SAT MORNING. BANKING ON ENHANCED LOW LEVEL CONVERGENCE
AND EVENTUAL FRONTAL PASSAGE TO ENHANCE SNOWFALL FROM GRAND MESA TO
THE WEST ELKS. WEST ELKS SHOULD ALSO BENEFIT FROM SOME MOIST
SOUTHERLY OROGRAPHIC FLOW TONIGHT...WHILE TRAILING NORTHERLY FLOW MAY
KEEP SOME LIGHT SNOW OVER GRAND MESA INTO SAT EVENING. AS SUCH...
ELECTED TO INCLUDE THE GRAND MESA AND WEST ELKS /ZONES 9 AND 12/ IN A
LOW-END ADVISORY TONIGHT INTO SAT EVENING FOR 4 TO 9 INCHES OF
SNOW. THE 700 MB LOW SHOULD ALSO BRING SNOW TO MANY CENTRAL VALLEYS
BUT WITH LITTLE ACCUMS EXPECTED.
SNOW DIMINISHES SAT NIGHT WITH CLEARING FROM THE NW. ERN UT/WRN CO
SHOULD BE IN BETWEEN SYSTEMS SUNDAY AS MODELS SHOW YET A THIRD
SPLITTING TROUGH APPROACHING FROM THE N LATE IN THE WEEKEND. WILL
TREND THE CHANCE OF PRECIP UP AGAIN ACROSS THE NORTHERN MTNS SUNDAY
AFTERNOON AS A RESULT.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE EARLY PART OF THE LONG TERM IS A CONTINUATION OF A REPEATING
PATTERN THAT HAS BEEN IN CONTROL SINCE THIS MIDWEEK. THE LAST OF A
SERIES OF SHORTWAVES WILL DROP SOUTHWARD INTO ARIZONA AND AGAIN FORM
A LOW TO OUR SOUTHWEST SUNDAY NIGHT INTO MONDAY. TODAY`S RUNS ARE
FARTHER WEST THAN YESTERDAY`S...WHICH DOES NOT ALLOW THE BEST
MOISTURE/DYNAMICS/OROGRAPHICS TO MOVE OVER OUR FORECAST AREA. THAT
SAID...THIS DISTURBANCE WILL BE IN CLOSE ENOUGH PROXIMITY FOR ANOTHER
ROUND OF MOUNTAIN SNOWFALL...WITH A CHANCE OF SNOW IN MANY VALLEYS.
THE FAVORED AREA WILL SWITCH FROM THE NORTH TO THE SOUTH LATE SUNDAY
NIGHT...WITH CLEARING OVER THE NORTH DURING THE DAY ON MONDAY. WINDS
DO NOT SEEM TO BE AS STRONG AS YESTERDAY`S SYSTEM...SO DO NOT
ANTICIPATE NEARLY AS MUCH BLOWING SNOW.
WE CONTINUE TO SEE SOME DISCREPANCIES IN RUN-TO-RUN AND BETWEEN-MODEL
SOLUTIONS FOR THE UPCOMING LONG TERM PERIOD. TODAY`S RUNS KEEP THE
AREA DRY THROUGH THE REMAINDER OF THE PERIOD. WE SIT UNDER A DRY AND
COLD NORTHWEST FLOW AS HIGH PRESSURE DOMINATES THE WEST COAST THROUGH
THE GREAT BASIN. THIS PATTERN IS NOW PROGGED TO PERSIST THROUGH THE
WORK WEEK. MODELS INDICATE THAT THERE MAY BE A COUPLE WEAK WAVES THAT
BRUSH THE NORTHERN EDGE...BUT THE TIMING AND TRACK IS BOUND TO CHANGE
WITH FUTURE MODEL RUNS.
TEMPERATURES WILL BE BELOW NORMAL IN THE DRY AIR MASS...ESPECIALLY AT
NIGHT. SOME MODIFICATION IS EXPECTED TOWARDS THE END OF THE PERIOD.
ANY WAVES THAT BRUSH THE AREA WILL ACT TO MODIFY TEMPS...AGAIN MAINLY
AT NIGHT.
&&
.AVIATION /FOR 00Z TAF ISSUANCE/...
SNOW HAS DEVELOPED OVER MANY MOUNTAIN AREAS AND IN SOME SOUTHERN
VALLEYS THIS AFTERNOON. THIS ACTIVITY IS EXPECTED TO BECOME MORE
WIDESPREAD THIS EVENING AND OVERNIGHT. THEREFORE MVFR/IFR VIS/CIGS IS
EXPECTED MUCH OF THE TIME OVER THE MOUNTAINS...AND FOR SHORTER
PERIODS IN THE VALLEYS. BY MIDNIGHT ALL TAF SITES WILL HAVE A CHANCE
OF MVFR/IFR AS THE CHANCE FOR PRECIPITATION SPREADS INTO THE LOWER
VALLEYS. SNOW AND LOW CLOUDS WILL CONTINUE...DIMINISHING FROM THE
NORTH DURING THE AFTERNOON. THEREFORE PERIODS OF MVFR/IFR ARE
EXPECTED THROUGH THE DAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONES
9/12/18.
WINTER STORM WARNING UNTIL 11 PM MST SATURDAY FOR ZONE 019.
WINTER WEATHER ADVISORY UNTIL 2 PM MST SATURDAY FOR ZONES 22/23.
UT...WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONE 28.
&&
$$
SHORT TERM...JAD
LONG TERM....EH
AVIATION.....EH
AREA FORECAST DISCUSSION
NWS NEW YORK NY
647 PM EST SAT DEC 3 2011
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA MOVES OFFSHORE TONIGHT...AND CONTINUES
TO TRACK EAST INTO THE START OF THE NEW WEEK. A SERIES OF LOW
PRESSURE CENTERS WILL RIDE ALONG A COLD FRONT THAT SLOWLY MOVES
THROUGH BY MID TO LATE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
HIGH PRESSURE SLOWLY PASSING EAST...WITH LIGHT ONSHORE FLOW
EXPECTED OVERNIGHT.
SATELLITE INDICATES PLENTY OF CIRRUS MOVING OVERHEAD AS UPPER
RIDGE AXIS SHIFTS EAST. IN ADDITION...SOME STRATUS TO THE EAST
COULD APPROACH AND AFFECT PORTIONS OF THE AREA...ESPECIALLY
EASTERN LOCALES. EVEN IF THE STRATUS DOES NOT ADVECT IN FROM THE
EAST...TIME HEIGHTS FROM RUC INDICATING POSSIBLE STRATUS
DEVELOPMENT LATER TONIGHT. SINCE THIS IS THE FIRST NIGHT OF
ONSHORE FLOW...NOT EXPECTING WIDESPREAD STRATUS AND FOG...BUT THIS
WILL NEED TO BE WATCHED.
AS FOR TEMPS...COULD VERY WELL SEE TEMPERATURES REMAIN NEARLY
STEADY OR RISE FROM THE CHILLY EVENING READINGS. THIS DUE TO
INCREASING MARINE LAYER AS LOW LEVEL WINDS SHIFT E/SE...ALBEIT
LIGHT. ALSO...CIRRUS MAY PREVENT TEMPS FROM BOTTOMING OUT.
AGAIN...THIS WILL NEED TO BE MONITORED TONIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
SOUTHERLY FLOW...ALONG WITH A RISE IN H8 TEMPS...WILL ALLOW FOR A
MOSTLY SUNNY DAY WITH TEMPS A FEW DEGREES WARMER THAN SATURDAY.
CLOUDS WILL INCREASE LATE IN THE DAY AS A STORM SYSTEM OVER THE
MIDWEST MOVES INTO THE GREAT LAKES ON SUNDAY...THEN NORTHEAST INTO
EASTERN CANADA AND THE CANADIAN MARITIMES SUNDAY NIGHT THROUGH
MONDAY MORNING. THE INCREASE IN CLOUDS WILL ALLOW TEMPS TO HOLD
STEADY AND THEN BEGIN TO DROP IN THE AFTERNOON SUNDAY. HIGHS WILL
TOP OFF IN THE LOW TO MID 50S ACROSS NORTHERN ZONES AND IN THE MID
TO UPPER 50S ACROSS SOUTHERN ZONES.
SEVERAL SHORTWAVES WILL MOVE THROUGH THE REGION SUNDAY NIGHT
THROUGH MONDAY AS A SECONDARY LOW FORMS OVER THE GULF COAST STATES
ON MONDAY. FOR THE LOCAL AREA...CAN EXPECT A PARTLY TO MOSTLY
CLOUDY DAY...BUT WITH H8 TEMPS WARMING TO 4-6C...ALONG WITH A
SOUTHERLY FLOW...TEMPS WILL REMAIN MILD ON MONDAY...TOPPING OFF IN
THE MID TO UPPER 50S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UNSETTLED AND SOMEWHAT UNCERTAIN PATTERN...AT LEAST WITH REGARD TO
SUBTLE DETAILS. LOOKING AT THE BIG PICTURE ACROSS THE NORTHERN
HEMISPHERE...COLD CORE LOW NEAR ALASKA SLOWLY SETTLES ACROSS
CENTRAL CANADA IN TIME. FURTHER SOUTH...TROUGH OUT WEST WILL
EVENTUALLY EJECT EAST. THIS TROUGH ELONGATED FROM NORTHEAST TO
SOUTHWEST...WITH A GENERAL AND BROAD SOUTHWEST FLOW FOR OUR AREA.
THIS PATTERN WILL RESULT IN A SLOW PROGRESSION TO THE SFC COLD
FRONT. EMBEDDED SHORTWAVES IN THIS SOUTHWEST FLOW WILL SET THE
STAGE FOR AT LEAST TWO AREAS OF LOW PRESSURE THAT WILL RIDE ALONG
THE FRONT. UNSETTLED WEATHER WILL BE THE RESULT...WITH PERHAPS THE
HIGHEST POPS BY MID WEEK AS TROUGH OUT WEST BEGINS IT/S EASTWARD
APPROACH.
FOR NOW...FOLLOWED HPC GUIDANCE AS GFS APPEARS TO BE AN AMPLIFIED
OUTLIER BY MID TO LATE WEEK.
MILD...ABOVE NORMAL TEMPS EXPECTED UNTIL THE FRONT FINALLY MOVES
THROUGH...SOMETIME WEDNESDAY OR WEDNESDAY NIGHT. THEN READINGS
SHOULD FALL BACK CLOSER TO NORMAL FOR THE LATTER PORTION OF THE
WEEK.
IF GFS IS INDEED CORRECT...ONE MORE MILD DAY COULD BE REALIZED
THURSDAY...BUT AGAIN WILL LEAN AWAY FROM THIS SLOWER MORE
AMPLIFIED SOLUTION AT THIS TIME.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE REMAINS OVER THE TERMINALS THROUGH THE TAF PERIOD.
VFR THROUGH THIS EVENING. THERE IS A CHANCE OF LOW-END VFR /HIGH-
END MVFR CEILINGS OVERNIGHT INTO SUNDAY MORNING. INTRODUCED SCT020
DECK IN MOST OF THE TAF SITES IN THE EARLY MORNING HOURS.
LIGHT WINDS OVERNIGHT. HIGH CONFIDENCE OF S-SW WIND DIRECTION
SUNDAY. OCCASIONAL GUSTS TO 15KT OR SLIGHTLY HIGHER SUNDAY
AFTERNOON...BUT CONFIDENCE TOO LOW TO INCLUDE IN TAFS AT THIS TIME.
OUTLOOK FOR 00Z SUNDAY THROUGH THURSDAY...
SUN NIGHT...CHANCE OF MVFR VSBYS WITH FOG LATE SUN NIGHT INTO
EARLY MON MORNING.
MON...VFR.
MON NIGHT-THURS...PERIODS OF SUB-VFR IN RAIN/SHOWERS.
&&
.MARINE...
HIGH PRES OVER THE WATERS MOVES OFFSHORE TONIGHT...AND REMAINS
EAST OF THE WATERS BEFORE SLOWLY MOVING OVER THE OPEN ATLANTIC
WATERS EARLY IN THE NEW WEEK.
A PERSISTENT SOUTHERLY SWELL OVER THE OCEAN WATERS WILL RESULT IN
SEAS UP TO 4 FT...AND MAY TOUCH 5 FT ON THE OUTER OCEAN WATERS
FROM TIME TO TIME. DO NOT THINK SEAS WILL BE ABOVE 5 FT FOR A
CONSISTENT PERIOD OF TIME...SO SCA NOT EXPECTED. SOUTHERLY WINDS
WILL REMAIN AT 10 KT OR LESS.
PERSISTENT SOUTHWEST OR SOUTH FLOW EXPECTED MONDAY THROUGH TUESDAY
NIGHT AHEAD OF THE SLOW MOVING COLD FRONT. ONCE LOW PRESSURE AND
THE FRONT MOVE EAST...WINDS PICK UP OUT OF THE NORTHWEST LATER
WEDNESDAY AND THURSDAY.
SEAS SHOULD REMAIN JUST BELOW OR PERHAPS RIGHT AT 5 FT THROUGH
TUESDAY NIGHT/EARLY WEDNESDAY. BEHIND THE FRONT...SEAS BUILD AS
WAVE WATCH III INDICATES.
FOR THE OTHER WATERS SURROUNDING LONG ISLAND...WILL FOLLOW BUOY
CLIMO BASED ON WINDS/FETCH.
&&
.HYDROLOGY...
DRY THROUGH MONDAY.
UNSETTLED WEATHER WITH POSSIBLE SIGNIFICANT RAINFALL TUESDAY
THROUGH WEDNESDAY. BEST CHANCE FOR ANY HEAVIER RAIN WOULD BE
WEDNESDAY INTO WEDNESDAY NIGHT.
STILL TOO EARLY TO DETERMINE EXTENT OF URBAN/RIVER FLOODING IF
ANY. STAY TUNED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MPS/PW
NEAR TERM...MPS/PW
SHORT TERM...MPS
LONG TERM...PW
AVIATION...KCS
MARINE...MPS/PW
HYDROLOGY...MPS/PW
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1219 PM EST FRI DEC 2 2011
.SYNOPSIS...
STRONG HIGH PRESSURE CENTERED IN THE PLAINS STATES HAS AN EXTENSION
TO THE MID-ATLANTIC COAST BUT IS AWAITING THE PASSAGE OF A WEAK
COLD FRONTAL PASSAGE THROUGH THE MID-ATLANTIC STATES LATER TODAY.
THE HIGH THEN BUILDS STRONGLY INTO NEW ENGLAND SATURDAY AND EDGES
OFFSHORE MONDAY. A COLD FRONT SHOULD BE STALLING OR DRIFTING EAST
FROM THE APPALACHIAN MOUNTAINS MONDAY THROUGH AT LEAST WEDNESDAY
AS A SERIES OF LOW PRESSURE SYSTEMS TRY TO MOVE NORTHEAST ALONG
THE FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT TO MANY CHANGES WITH THIS UPDATE. A FRONTAL BOUNDARY WILL MOVE
ACROSS NEW ENGLAND TODAY. BANDS OF HIGH CIRRUS CLOUDS ARE FORMING
ACROSS THE PHILADELPHIA METRO REGION AND POINTS NORTH, THESE ARE
ACCOUNTED FOR IN UPDATED SKY GRIDS. LATEST 16Z RUC KEEPS AND PRECIP
WELL TO OUR NORTH. THIS FITS NICELY WITH RH VALUES NOT IDEAL FOR
PRECIPITATION ALONG WITH WEEK LIFT CHARACTERIZED BY A LACK OF PVA
AND 700 MB OMEGA. ANY RADAR ECHOS ACROSS THE NORTH THIS AFTERNOON
WILL BE VIRGA. SURFACE TEMPERATURES HAVE REBOUNDED NICELY AHEAD OF
THE FRONT EVEN AFTER A CHILLY START AND HAVE ADJUSTED TEMPERATURE
GRIDS AGAIN BASED OFF OF 17Z METAR OBS. FRONT SHOULD BRING
SOUTHERLY WINDS THIS AFTERNOON SWITCHING TO NORTHWESTERLY, MADE
FEW CHANGES TO WIND. WIND GUSTS GRIDS BETTER MATCH SURROUNDING
WFOS WITH THIS UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
TONIGHT IS A CLEAR NIGHT WITH A BIT OF NW BECOMING NORTH BREEZE
DURING THE NIGHT AND TEMPS COOLING TO ABOUT THE SAME VALUES OR
SLIGHTLY LOWER THAN WHAT OCCURRED THIS FROSTY FRIDAY MORNING.
LOWERED THE TEMPS SLIGHTLY IN THE PHL-TTN URBAN CENTERS WITH NORTH
WIND TONIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
FAIR WEATHER IS EXPECTED ACROSS THE AREA THIS WEEKEND AS HIGH
PRESSURE REMAINS IN CONTROL OF THE WEATHER. BOTH THE EC AND GFS
AGREE THAT THE HIGH WILL CREST OVER THE AREA SAT NIGHT AND THEN
MOVE OFF INTO THE NORTH ATLANTIC SUN. SKIES WILL BE MOSTLY CLR
SAT AND PARTLY TO MOSTLY CLR SUN. CLOUDS MAY ARRIVE LATER SUN WITH
THE RETURN FLOW BEHIND THE HIGH BRINGING MOISTURE FROM OFF THE
OCEAN.
A LOW MOVES ACROSS SRN CANADA SUN NGT INTO MON CAUSING A FRONT TO
DROP DOWN FROM THE NORTH. THIS FRONT STALLS ACROSS THE AREA
ALLOWING ANOTHER LOW TO DEVELOP ON IT AND MOVE ACROSS THE AREA MON
NGT INTO WED. THE GFS AND EC OFFER DIFFERENT SOLUTIONS WITH
REGARDS TO HOW MUCH PRECIP ARRIVES AND WHEN. BOTH MODELS HAVE SOME
QPF ARRIVING TUE...BUT THE EC HAS HEAVIER QPF ACROSS THE AREA WED
NIGHT INTO THU WHILE THE GFS HAS THE BULK OF ITS QPF TUE NIGHT
INTO WED. THE OVERNIGHT EXTENDED GRIDS HAVE MADE ONLY SMALL
CHANGES TO THE EARLIER FCST WITH CHC POPS THROUGH MUCH OF THE MON
NGT-THU PERIOD ATTM. A LITTLE SNOW MAY MIX IN WED NIGHT ACROSS THE
NRN AREAS.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR MOSTLY CLEAR. PATCHY THICK CI ESPECIALLY 16Z-20Z...MAINLY
N OF PHL. SCT CLDS 5000-8000 FT EXPECTED WITH THE LATE AFTN CFP.
W GUSTS TO 15 KTS AT 18Z SHIFT NW AROUND 21Z WITH GUSTS 20 KTS...
ISOLATED GUSTS TO 25 KTS POSSIBLE NEAR 23Z/2.
TONIGHT...VFR CLEAR. NW WIND 5 TO 15 KTS BECOMING N DURING THE NIGHT.
PHILADELPHIA SPECIFIC...HIGH CONFIDENCE FCST OF VFR CLEAR THROUGH
17Z WITH A BAND OF CI POSSIBLE 18Z-20Z. WIND AT 18Z W GUST 15 KT.
AFTER 20Z...WSHIFT NW WITH GUSTS 20 KTS AND A FEW SC/CU 6000-8000
FT. LOW PROB ISO NW GUSTS 25 KTS IN THE 21Z-23Z TIME FRAME.
OUTLOOK...
VFR CONDITIONS EXPECTED SAT AND MUCH OF SUN. LOW CLOUDS MAY ARRIVE
BEHIND THE DEPARTING HIGH LATER SUN INTO MON. POOR FLYING CONDITIONS
TUE INTO THU WITH THE NEXT SYSTEM ARRIVING FROM THE MIDWEST STATES.
&&
.MARINE...
TODAY...LIGHT WIND TO START BECOMING INCREASINGLY GUSTY WEST THIS
AFTN.
TONIGHT...SCA ISSUED. MARGINAL CONFIDENCE IN THIS ADVY FOR SCT
GUSTS 22-25 KTS MAINLY IN THE 23Z-05Z TIME FRAME. 44009 SEAS
EXPECTED TO INCREASE TO 5 FT LATER TONIGHT SO HAVE TWO SEGMENTS...
A NJ SEGMENT FOR THIS EVENING AND A LATER LENGTHIER TIME FRAME
SEGMENT FOR THE DELAWARE ATLC WATERS.
NO HEADLINE POSTED YET FOR LOWER DELAWARE BAY. THAT CAN BE ADDED
LATER BY FUTURE SHIFTS IF CONFIDENCE INCREASES.
STRUGGLED TO GET THE GRIDDED GUSTS TO CRITERIA VIA SEVERAL TOOL
APPLICATIONS.
SREF STILL NOT A HINT OF SUSTAINED 25 KT WINDS ALONG OUR COASTS.
UPDATE: LOWERED WAVE HEIGHTS AGAIN SLIGHTLY FOR THE NEXT FEW
HOURS BASED ON BUOY OBSERVATIONS WILL MONITOR THROUGHOUT THE DAY
WITH RESPECT TO THE SMALL CRAFT ADV SET TO GO INTO EFFECT LATE
THIS AFTERNOON. AGREE WITH PREVIOUS FORECASTER THINKING THAT IT IS
QUESTIONABLE WE MEET SMALL CRAFT ADV CONDITIONS.
OUTLOOK...
HIGH PRESSURE WILL BE ACROSS THE WATERS THIS WEEKEND WITH WINDS
AND SEAS EXPECTED TO REMAIN SUB-SCA THROUGH THE PERIOD. THE HIGH
WILL MOVE AWAY EARLY NEXT WEEK WHILE LOW PRESSURE AND A SERIES OF
FRONTS ARRIVE OVER OUR WATERS MON NGT INTO WED. WINDS AND SEAS
WILL EVENTUALLY RISE INTO SCA CRITERIA PROBABLY BY TUE NIGHT AND
THIS WILL PERSIST INTO THU.
&&
.CLIMATE...
DAILY CLI: GED 1203Z-1207Z TRACE OF SNOW IN CLEAR SKY REMOVED FROM
THE 430PM CLI RUN.
RAN THE MONTHLY CLM`S WITH JUST CURSORY CHECK OF THE DATA. IF YOU
NOTICE ANY ERRORS PLEASE GIVE US A CALL.
YOU SAW THE RER`S ISSUED EARLY THURSDAY MORNING REGARDING MONTHLY
AND SEASONAL RANKING OF THE TEMPS/QPF!
LA NINA OHIO VALLEY STORM TRACK CONTS TO LOOK ACTIVE AND MOST
INDICATIONS ARE THAT THE PRECIPITATION EVENT FROM LATE MONDAY INTO
WEDNESDAY WILL AT SOME POINT RAISE THE YEARLY WATER EQUIVALENT
PCPN TOTAL AT KABE TO RECORD VALUES...NEEDING ONLY .16 INCHES TO
EXCEED THE YEARLY RECORD OF 67.69 INCHES.
NOTING THAT PHL AVG TEMP IS HEADED FOR ITS 13TH CONSECUTIVE ABOVE
NORMAL DAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 1 AM EST
SATURDAY FOR ANZ450>453.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EST
SATURDAY FOR ANZ454-455.
&&
$$
SYNOPSIS...DRAG/GORSE
NEAR TERM...GAINES
SHORT TERM...DRAG
LONG TERM...O`HARA
AVIATION...DRAG/O`HARA
MARINE...DRAG/GAINES/O`HARA
CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
920 AM EST FRI DEC 2 2011
.SYNOPSIS...
STRONG HIGH PRESSURE CENTERED IN THE PLAINS STATES HAS AN EXTENSION
TO THE MID-ATLANTIC COAST BUT IS AWAITING THE PASSAGE OF A WEAK
COLD FRONTAL PASSAGE THROUGH THE MID-ATLANTIC STATES LATER TODAY.
THE HIGH THEN BUILDS STRONGLY INTO NEW ENGLAND SATURDAY AND EDGES
OFFSHORE MONDAY. A COLD FRONT SHOULD BE STALLING OR DRIFTING EAST
FROM THE APPALACHIAN MOUNTAINS MONDAY THROUGH AT LEAST WEDNESDAY
AS A SERIES OF LOW PRESSURE SYSTEMS TRY TO MOVE NORTHEAST ALONG
THE FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT TO MANY CHANGES WITH THIS UPDATE. A FRONTAL BOUNDARY WILL MOVE
ACROSS NEW ENGLAND TODAY. THIS MAY RESULT IN SOME HIGH CIRRUS THIS
AFTERNOON AS DISCUSSED BY PREVIOUS SHIFTS. LATEST 12Z RUC KEEPS ANY
PRECIP WELL TO OUR NORTH. A CONCERN MAY BE SOME CAA THIS AFTERNOON
BEHIND THE FRONT RESULTING IN THE LOWERING HIGH TEMPERATURES A
TOUCH. CURRENT TEMPERATURES AND DEWPOINTS ALSO HAVE BEEN ADJUSTED SLIGHTLY
BASED ON 14Z METAR OBS. FRONT SHOULD BRING SOUTHERLY WINDS THIS
AFTERNOON SWITCHING TO NORTHWESTERLY, MADE FEW CHANGES TO WIND.
LOWERED WAVE HEIGHTS SLIGHTLY FOR THE NEXT FEW HOURS BASED ON BUOY
OBSERVATIONS WILL MONITOR THROUGHOUT THE DAY WITH RESPECT TO THE
SMALL CRAFT ADVISORY SET TO GO INTO EFFECT LATE THIS
AFTERNOON/TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
TONIGHT IS A CLEAR NIGHT WITH A BIT OF NW BECOMING NORTH BREEZE
DURING THE NIGHT AND TEMPS COOLING TO ABOUT THE SAME VALUES OR
SLIGHTLY LOWER THAN WHAT OCCURRED THIS FROSTY FRIDAY MORNING.
LOWERED THE TEMPS SLIGHTLY IN THE PHL-TTN URBAN CENTERS WITH NORTH
WIND TONIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
FAIR WEATHER IS EXPECTED ACROSS THE AREA THIS WEEKEND AS HIGH
PRESSURE REMAINS IN CONTROL OF THE WEATHER. BOTH THE EC AND GFS
AGREE THAT THE HIGH WILL CREST OVER THE AREA SAT NIGHT AND THEN
MOVE OFF INTO THE NORTH ATLANTIC SUN. SKIES WILL BE MOSTLY CLR
SAT AND PARTLY TO MOSTLY CLR SUN. CLOUDS MAY ARRIVE LATER SUN WITH
THE RETURN FLOW BEHIND THE HIGHBRINGING MOISTURE FROM OFF THE
OCEAN.
A LOW MOVES ACROSS SRN CANADA SUN NGT INTO MON CAUSING A FRONT TO
DROP DOWN FROM THE NORTH. THIS FRONT STALLS ACROSS THE AREA
ALLOWING ANOTHER LOW TO DEVELOP ON IT AND MOVE ACROSS THE AREA MON
NGT INTO WED. THE GFS AND EC OFFER DIFFERENT SOLUTIONS WITH
REGARDS TO HOW MUCH PRECIP ARRIVES AND WHEN. BOTH MODELS HAVE SOME
QPF ARRIVING TUE...BUT THE EC HAS HEAVIER QPF ACROSS THE AREA WED
NIGHT INTO THU WHILE THE GFS HAS THE BULF OF ITS QPF TUE NIGHT
INTO WED. THE OVERNIGHT EXTENDED GRIDS HAVE MADE ONLY SMALL
CHANGES TO THE EARLIER FCST WITH CHC POPS THROUGH MUCH OF THE MON
NGT-THU PERIOD ATTM. A LITTLE SNOW MAY MIX IN WED NIGHT ACROSS THE
NRN AREAS.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR MOSTLY CLEAR. PATCHY THICK CI ESPECIALLY 16Z-20Z...MAINLY
N OF PHL. SCT CLDS 5000-8000 FT EXPECTED WITH THE LATE AFTN CFP.
W GUSTS TO 15 KTS AT 18Z SHIFT NW AROUND 21Z WITH GUSTS 20 KTS...
ISOLATED GUSTS TO 25 KTS POSSIBLE NEAR 23Z/2.
TONIGHT...VFR CLEAR. NW WIND 5 TO 15 KTS BECOMING N DURING THE NIGHT.
PHILADELPHIA SPECIFIC...HIGH CONFIDENCE FCST OF VFR CLEAR THROUGH
17Z WITH A BAND OF CI POSSIBLE 18Z-20Z. WIND AT 18Z W GUST 15 KT.
AFTER 20Z...WSHIFT NW WITH GUSTS 20 KTS AND A FEW SC/CU 6000-8000
FT. LOW PROB ISO NW GUSTS 25 KTS IN THE 21Z-23Z TIME FRAME.
OUTLOOK...
VFR CONDITIONS EXPECTED SAT AND MUCH OF SUN. LOW CLOUDS MAY ARRIVE
BEHIND THE DEPARTING HIGH LATER SUN INTO MON. POOR FLYING CONDITIONS
TUE INTO THU WITH THE NEXT SYSTEM ARRIVING FROM THE MIDWEST STATES.
&&
.MARINE...
TODAY...LIGHT WIND TO START BECOMING INCREASINGLY GUSTY WEST THIS
AFTN.
TONIGHT...SCA ISSUED. MARGINAL CONFIDENCE IN THIS ADVY FOR SCT
GUSTS 22-25 KTS MAINLY IN THE 23Z-05Z TIME FRAME. 44009 SEAS
EXPECTED TO INCREASE TO 5 FT LATER TONIGHT SO HAVE TWO SEGMENTS...
A NJ SEGMENT FOR THIS EVENING AND A LATER LENGTHIER TIME FRAME
SEGMENT FOR THE DELAWARE ATLC WATERS.
NO HEADLINE POSTED YET FOR LOWER DELAWARE BAY. THAT CAN BE ADDED
LATER BY FUTURE SHIFTS IF CONFIDENCE INCREASES.
STRUGGLED TO GET THE GRIDDED GUSTS TO CRITERIA VIA SEVERAL TOOL
APPLICATIONS.
SREF STILL NOT A HINT OF SUSTAINED 25 KT WINDS ALONG OUR COASTS.
OUTLOOK...
HIGH PRESSURE WILL BE ACROSS THE WATERS THIS WEEKEND WITH WINDS
AND SEAS EXECTED TO REMAIN SUB-SCA THROUGH THE PERIOD. THE HIGH
WILL MOVE AWAY EARLY NEXT WEEK WHILE LOW PRESSURE AND A SERIES OF
FRONTS ARRIVE OVER OUR WATERS MON NGT INTO WED. WINDS AND SEAS
WILL EVENTUALLY RISE INTO SCA CRITERIA PROBABLY BY TUE NIGHT AND
THIS WILL PERSIST INTO THU.
&&
.CLIMATE...
DAILY CLI: GED 1203Z-1207Z TRACE OF SNOW IN CLEAR SKY REMOVED FROM
THE 430PM CLI RUN.
RAN THE MONTHLY CLM`S WITH JUST CURSORY CHECK OF THE DATA. IF YOU
NOTICE ANY ERRORS PLEASE GIVE US A CALL.
YOU SAW THE RER`S ISSUED EARLY THURSDAY MORNING REGARDING MONTHLY
AND SEASONAL RANKING OF THE TEMPS/QPF!
LA NINA OHIO VALLEY STORM TRACK CONTS TO LOOK ACTIVE AND MOST
INDICATIONS ARE THAT THE PRECIPITATION EVENT FROM LATE MONDAY INTO
WEDNESDAY WILL AT SOME POINT RAISE THE YEARLY WATER EQUIVALENT
PCPN TOTAL AT KABE TO RECORD VALUES...NEEDING ONLY .16 INCHES TO
EXCEED THE YEARLY RECORD OF 67.69 INCHES.
NOTING THAT PHL AVG TEMP IS HEADED FOR ITS 13TH CONSECUTIVE ABOVE
NORMAL DAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 1 AM EST
SATURDAY FOR ANZ450>453.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EST
SATURDAY FOR ANZ454-455.
&&
$$
SYNOPSIS...DRAG/GORSE
NEAR TERM...GAINES
SHORT TERM...DRAG
LONG TERM...O`HARA
AVIATION...DRAG/O`HARA
MARINE...DRAG/O`HARA
CLIMATE...
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
954 AM EST FRI DEC 2 2011
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A WEAKENING COLD FRONT FROM NORTHERN INDIANA TO SOUTHEAST MISSOURI
WILL MOVE INTO OUR REGION LATER TODAY AND GRADUALLY DISSIPATE. AN
AREA OF HIGH PRESSURE BEHIND THE FRONT WILL DOMINATE OUR WEATHER
TONIGHT AND SATURDAY. RAIN WILL SPREAD INTO OUR REGION LATE
SATURDAY NIGHT AND SUNDAY AS ANOTHER AND STRONGER COLD FRONT MOVES
OUR WAY. SEVERAL MODELS STALL THIS FRONT FROM THE LOWER MISSISSIPPI
VALLEY TO OHIO EARLY NEXT WEEK...KEEPING SOUTHERN SECTIONS VERY
WET. FARTHER NORTH MIXED PRECIP WILL BE THE RULE AS COLDER AIR
SPREADS INTO OUR REGION. FINALLY DRY AND COLD WEATHER WILL BE THE
RULE AFTER THE MIDDLE OF NEXT WEEK AS THE FRONT TO OUR EAST MOVES
EAST AND HIGH PRESSURE OVER THE ROCKIES BUILDS OUR WAY.
&&
.NEAR TERM /REST OF TODAY/...
UPDATE...FORECAST GENERALLY LOOKS TO BE IN GREAT SHAPE. ONLY
NEEDED TO MAKE A FEW MINOR TWEAKS TO ACCOUNT FOR LATEST TRENDS.
BY MIDDAY MODELS SHOW QUITE A BIT OF DRYING AS HIGH PRESSURE
BUILDS INTO THE GREAT LAKES AND DOWNWARD VERTICAL VELOCITIES
OCCUR...SKIES SHOULD BECOME MOSTLY SUNNY EVERYWHERE LATE.
VISIBLE SATELLITE AND OBSERVATIONS INDICATE A LITTLE REMAINING
SNOW COVER ACROSS PARTS OF OUR FAR NORTH AND NORTHEAST WHICH MAY
HOLD TEMPERATURES DOWN THERE JUST A LITTLE. OTHERWISE...WENT NEAR
A MAV/MET BLEND ON TEMPERATURES MOST OTHER AREAS TODAY FOR HIGHS
IN THE 40S.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
MODELS ARE IN GOOD AGREEMENT THIS PERIOD SO USED A BLEND WITH ONLY
MINOR ADJUSTMENTS.
SATURDAY WILL BE MILD AND DRY AS A SOUTHERLY FLOW INCREASES ACROSS
OUR REGION AS THE RESULT OF HIGH PRESSURE OVER THE EASTERN U.S. AND
LOW PRESSURE MOVING FROM THE CENTRAL PLAINS TOWARDS THE GREAT
LAKES.
MODELS THIS RUN ARE A TAD SLOWER IN BEGINNING PRECIP MAINLY LATE
SATURDAY NIGHT AND MAINTAINING IT A LITTLE FARTHER NORTH SUNDAY AND
SUNDAY NIGHT. A COLD FRONT WILL MOVE EAST ACROSS OUR REGION SUNDAY
AND STALL NEAR OR JUST A LITTLE SOUTH OF THE OHIO RIVER SUNDAY
NIGHT. IN MOST CASES...WENT CLOSE TO A MOS BLEND ON TEMPERATURES
AND POPS.
A PERIOD OF MIXED PRECIP POSSIBLE ACROSS OUR NORTH MAINLY LATE
SUNDAY NIGHT AS TEMPERATURES AND THICKNESSES DROP NEAR CRITICAL
VALUES. OTHERWISE...PRECIP ALL RAIN OTHER PERIODS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE MAIN FOCUS IS COMPRISED OF PRECIP CHANCES AT THE BEGINNING OF
THE EXTENDED PERIOD IN REGARD TO A STATIONARY FRONT OVER THE
TENNESSEE VALLEY...AND THE NEXT UPPER LEVEL LOW AT THE END OF THE
PERIOD.
THE EXTENDED STARTS OUT WITH A COLD FRONT LINGERING AROUND THE OHIO
RIVER ON MONDAY...AND MODELS SEEM TO BE IN AGREEMENT WITH THIS.
SO...WILL STAY WITH INITIALIZATION NUMBERS...WHICH PUT THE HIGHEST
POPS ACROSS THE SOUTHERN PORTIONS OF CENTRAL INDIANA THROUGH MONDAY
NIGHT.
THE NEXT PART OF THE EXTENDED FORECAST BECOMES MORE NEBULOUS. GFS
AND EURO CONTINUE TO BE IN DISAGREEMENT IN REGARD TO APPROACHING
UPPER LEVEL LOW. THE AGREEMENT IN TIMING BETWEEN THE 2 MODELS SEEMS
EVEN WORSE THAN YESTERDAY WITH THE GFS SPEEDING THE TROUGH UP EVEN
MORE. THE GFS IS SHOWING THE DEEP UPPER LOW OVER THE UPPER MIDWEST
BY TUESDAY AFTERNOON...WHILE THE EURO HAS IT FORMING INTO A CUT-OFF
LOW OVER THE SOUTHERN PLAINS. BY THE TIME THE EURO HAS THE LOW IN
THE MIDWEST ON WEDNESDAY AFTERNOON THE GFS ALREADY HAS IT OVER LAKE
ONTARIO. IN ADDITION...THE GFS IS SHOWING A DEEP CUT-OFF LOW OVER
THE LOWER MISSISSIPPI VALLEY BEHIND THE INITIAL WAVE...WHEREAS THE
EURO ONLY HINTS AT IT.
OF THE 2 MODELS...THE INITIALIZATION NUMBERS CONTINUE TO FAVOR THE
DRIER GFS. AGAIN...THERE IS STILL NOT CONSISTENT ENOUGH TRENDING TO
DEVIATE FROM THE INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR THE 02/15Z IND TAF UPDATE/...
NO CHANGES NECESSARY FOR THE MOMENT. POSTFRONTAL AREA OF IFR
CEILINGS/MVFR VISIBILITIES WILL REQUIRE MONITORING...ESPECIALLY AT
LAF/HUF AND PERHAPS AT IND. RUC SOUNDING AT LAF BEGINNING TO LOOK
TROUBLESOME FOR THE NEXT FEW HOURS...ALTHOUGH STILL EXPECTING TO
ERODE ENOUGH TO AVOID IMPACTING TAF SITES. PREVIOUS DISCUSSION
FOLLOWS.
MID AND HIGH LEVEL CLOUDS WILL AFFECT TAF SITES THIS MORNING IN
WAKE OF A WEAK FRONTAL BOUNDARY...BUT CONDITIONS SHOULD STILL
STAY AT VFR CATEGORY. MUCH DRIER AIR WILL QUICKLY FILTER INTO TAF
SITES BY EARLY AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE
MIDWEST. SO...VFR CONDITIONS WILL PREVAIL FOR ENTIRE TAF PERIOD.
MID LEVEL CLOUDS WILL INCREASE EARLY TOMORROW MORNING AHEAD OF
THE NEXT UPPER LEVEL DISTURBANCE...BUT AGAIN VFR CONDITIONS ARE
EXPECTED. WINDS WILL SLOWLY VEER TO THE EAST/SOUTHEAST THROUGH THE
COURSE OF THIS AFTERNOON BUT WILL REMAIN LIGHT AT 4 TO 8 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/SMF
SHORT TERM...JH
LONG TERM....TDUD
AVIATION...TDUD/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
928 AM EST FRI DEC 2 2011
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A WEAKENING COLD FRONT FROM NORTHERN INDIANA TO SOUTHEAST MISSOURI
WILL MOVE INTO OUR REGION LATER TODAY AND GRADUALLY DISSIPATE. AN
AREA OF HIGH PRESSURE BEHIND THE FRONT WILL DOMINATE OUR WEATHER
TONIGHT AND SATURDAY. RAIN WILL SPREAD INTO OUR REGION LATE
SATURDAY NIGHT AND SUNDAY AS ANOTHER AND STRONGER COLD FRONT MOVES
OUR WAY. SEVERAL MODELS STALL THIS FRONT FROM THE LOWER MISSISSIPPI
VALLEY TO OHIO EARLY NEXT WEEK...KEEPING SOUTHERN SECTIONS VERY
WET. FARTHER NORTH MIXED PRECIP WILL BE THE RULE AS COLDER AIR
SPREADS INTO OUR REGION. FINALLY DRY AND COLD WEATHER WILL BE THE
RULE AFTER THE MIDDLE OF NEXT WEEK AS THE FRONT TO OUR EAST MOVES
EAST AND HIGH PRESSURE OVER THE ROCKIES BUILDS OUR WAY.
&&
.NEAR TERM /TODAY/...
AN EXTENSIVE AREA OF MID CLOUDS ACROSS NORTHERN INDIANA AND CENTRAL
ILLINOIS WAS SPREADING INTO OUR REGION THIS MORNING. EARLY ON EXPECT
THE NORTHWEST HALF OF OUR REGION TO BE MOSTLY CLOUDY. BUT BY MIDDAY
MODELS SHOW QUITE A BIT OF DRYING AS HIGH PRESSURE BUILDS INTO THE
GREAT LAKES AND DOWNWARD VERTICAL VELOCITIES OCCUR. MAIN FOCUS WILL
BE HOW LONG CLOUDS REMAIN. SLOWED DOWN CLEARING JUST A LITTLE.
OTHERWISE...WENT CLOSE TO A MODEL BLEND.
VISIBLE SATELLITE YESTERDAY INDICATED A LITTLE REMAINING SNOW COVER
ACROSS PARTS OF OUR FAR NORTH AND NORTHEAST WHICH MAY HOLD
TEMPERATURES DOWN THERE JUST A LITTLE. OTHERWISE...WENT NEAR A
MAV/MET BLEND ON TEMPERATURES MOST OTHER AREAS TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
MODELS ARE IN GOOD AGREEMENT THIS PERIOD SO USED A BLEND WITH ONLY
MINOR ADJUSTMENTS.
SATURDAY WILL BE MILD AND DRY AS A SOUTHERLY FLOW INCREASES ACROSS
OUR REGION AS THE RESULT OF HIGH PRESSURE OVER THE EASTERN U.S. AND
LOW PRESSURE MOVING FROM THE CENTRAL PLAINS TOWARDS THE GREAT
LAKES.
MODELS THIS RUN ARE A TAD SLOWER IN BEGINNING PRECIP MAINLY LATE
SATURDAY NIGHT AND MAINTAINING IT A LITTLE FARTHER NORTH SUNDAY AND
SUNDAY NIGHT. A COLD FRONT WILL MOVE EAST ACROSS OUR REGION SUNDAY
AND STALL NEAR OR JUST A LITTLE SOUTH OF THE OHIO RIVER SUNDAY
NIGHT. IN MOST CASES...WENT CLOSE TO A MOS BLEND ON TEMPERATURES
AND POPS.
A PERIOD OF MIXED PRECIP POSSIBLE ACROSS OUR NORTH MAINLY LATE
SUNDAY NIGHT AS TEMPERATURES AND THICKNESSES DROP NEAR CRITICAL
VALUES. OTHERWISE...PRECIP ALL RAIN OTHER PERIODS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE MAIN FOCUS IS COMPRISED OF PRECIP CHANCES AT THE BEGINNING OF
THE EXTENDED PERIOD IN REGARD TO A STATIONARY FRONT OVER THE
TENNESSEE VALLEY...AND THE NEXT UPPER LEVEL LOW AT THE END OF THE
PERIOD.
THE EXTENDED STARTS OUT WITH A COLD FRONT LINGERING AROUND THE OHIO
RIVER ON MONDAY...AND MODELS SEEM TO BE IN AGREEMENT WITH THIS.
SO...WILL STAY WITH INITIALIZATION NUMBERS...WHICH PUT THE HIGHEST
POPS ACROSS THE SOUTHERN PORTIONS OF CENTRAL INDIANA THROUGH MONDAY
NIGHT.
THE NEXT PART OF THE EXTENDED FORECAST BECOMES MORE NEBULOUS. GFS
AND EURO CONTINUE TO BE IN DISAGREEMENT IN REGARD TO APPROACHING
UPPER LEVEL LOW. THE AGREEMENT IN TIMING BETWEEN THE 2 MODELS SEEMS
EVEN WORSE THAN YESTERDAY WITH THE GFS SPEEDING THE TROUGH UP EVEN
MORE. THE GFS IS SHOWING THE DEEP UPPER LOW OVER THE UPPER MIDWEST
BY TUESDAY AFTERNOON...WHILE THE EURO HAS IT FORMING INTO A CUT-OFF
LOW OVER THE SOUTHERN PLAINS. BY THE TIME THE EURO HAS THE LOW IN
THE MIDWEST ON WEDNESDAY AFTERNOON THE GFS ALREADY HAS IT OVER LAKE
ONTARIO. IN ADDITION...THE GFS IS SHOWING A DEEP CUT-OFF LOW OVER
THE LOWER MISSISSIPPI VALLEY BEHIND THE INITIAL WAVE...WHEREAS THE
EURO ONLY HINTS AT IT.
OF THE 2 MODELS...THE INITIALIZATION NUMBERS CONTINUE TO FAVOR THE
DRIER GFS. AGAIN...THERE IS STILL NOT CONSISTENT ENOUGH TRENDING TO
DEVIATE FROM THE INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR THE 02/15Z IND TAF UPDATE/...
NO CHANGES NECESSARY FOR THE MOMENT. POSTFRONTAL AREA OF IFR
CEILINGS/MVFR VISIBILITIES WILL REQUIRE MONITORING...ESPECIALLY AT
LAF/HUF AND PERHAPS AT IND. RUC SOUNDING AT LAF BEGINNING TO LOOK
TROUBLESOME FOR THE NEXT FEW HOURS...ALTHOUGH STILL EXPECTING TO
ERODE ENOUGH TO AVOID IMPACTING TAF SITES. PREVIOUS DISCUSSION
FOLLOWS.
MID AND HIGH LEVEL CLOUDS WILL AFFECT TAF SITES THIS MORNING IN
WAKE OF A WEAK FRONTAL BOUNDARY...BUT CONDITIONS SHOULD STILL
STAY AT VFR CATEGORY. MUCH DRIER AIR WILL QUICKLY FILTER INTO TAF
SITES BY EARLY AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE
MIDWEST. SO...VFR CONDITIONS WILL PREVAIL FOR ENTIRE TAF PERIOD.
MID LEVEL CLOUDS WILL INCREASE EARLY TOMORROW MORNING AHEAD OF
THE NEXT UPPER LEVEL DISTURBANCE...BUT AGAIN VFR CONDITIONS ARE
EXPECTED. WINDS WILL SLOWLY VEER TO THE EAST/SOUTHEAST THROUGH THE
COURSE OF THIS AFTERNOON BUT WILL REMAIN LIGHT AT 4 TO 8 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM....TDUD
AVIATION...TDUD/NIELD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
600 PM CST SAT DEC 3 2011
.AVIATION...
MVFR/VFR CONDITIONS EARLY THIS EVENING WILL DETERIORATE AS A
SURFACE LOW MOVES FROM NORTHWEST MO THROUGH EASTERN IA BY 06Z.
CID/DBQ WILL BE NEAR THE CENTER OF THE LOW AND SHOULD EXPERIENCE
THE LOWEST CONDITIONS WITH CIGS BLO 5HND FT AND VSBYS AROUND 2SM
OR LESS IN RA/BR. AFTER MIDNIGHT AS THE LOW PULLS AWAY FROM THE
AREA CONDITIONS WILL GRADUALLY IMPROVE WITH WINDS BECOMING WEST
AND THEN NORTHWEST. THE RAIN WILL BE ENDING OVER THE AREA BETWEEN
08Z AND 12Z. CID/DBQ COULD SEE THE PRECIPITATION CHANGE TO SNOW
BRIEFLY BEFORE ENDING. AFTER 12Z EXPECT MVFR CIGS WITH VSBYS
IMPROVING TO 6SM OR BETTER BY LATE MORNING. ..DLF..
&&
.PREV DISCUSSION... /ISSUED 308 PM CST SAT DEC 3 2011/
SYNOPSIS...
MAIN FEATURE OF INTEREST IS THE UPPER LEVEL LOW OVER LAS VEGAS WITH
A LEAD WAVE EJECTING OVER WESTERN KANSAS AT 18Z. MEANWHILE...
SURFACE LOW IS LOCATED IN SOUTH-CENTRAL KANSAS WITH THE COLD FRONT
EXTENDING NORTH TO FORT DODGE /KFOD/ AND THE UPPER PENINSULA. TEMPS
BEHIND THE FRONT DIVE FROM THE MID AND SOME UPPER 40S INTO THE LOWER
30S. LARGE AREA OF RAIN IN THE WARM SECTOR LIFTED NORTH TODAY WITH
PRECIP AMOUNTS TYPICALLY IN THE ONE HALF TO ONE INCH RANGE. NEXT
ROUND OF PRECIP ASSOCIATED WITH THE MAIN COLD FRONT NOW SPANNING
CENTRAL IOWA AND MUCH OF MISSOURI.
SHORT TERM...TONIGHT AND SUNDAY...
MAIN FORECAST CONCERN TONIGHT IS THE BEHAVIOR OF THE NEXT ROUND OF
PRECIP. RUC BRINGS THE SURFACE LOW OVER VINTON /KVTI/ BY 03Z THIS
EVENING. THIS IS SLIGHTLY FASTER AND FARTHER NORTHWEST THAN MODEL
FORECASTS HAD BEEN BUT IS IN LINE WITH THE OVERALL TREND TO A WARMER
FORECAST. IN TERMS OF PRECIP...THIS MORE WESTERN TRACK...AS SEEN IN
THE RUC AND CURRENT RADAR TRENDS...SUGGESTS RAIN THROUGH THE EVENING
WITH ONLY A BRIEF CHANGE TO SNOW IN THE FAR NORTHERN COUNTIES BEFORE
PRECIP ENDS LATE TONIGHT/EARLY SUNDAY MORNING. MUCH OF THE AREA TO
BE DRY-SLOTTED OVERNIGHT WITH ONLY THE NORTHERN AND WESTERN SECTIONS
EXPECTED TO SEE WRAP-AROUND PRECIP AS THE LOW RACES OFF TO THE
NORTHEAST. EVEN SO...BUFKIT SOUNDINGS FOR KCID AND KDBQ LIMIT ANY
FROZEN PRECIP TO ONLY AN HOUR OR TWO BEFORE ENDING ALTOGETHER. THUS
HAVE REDUCED SNOW AMOUNTS AND ENDED PRECIP A FEW HOURS EARLIER THAN
PREVIOUS FORECAST. ..DMD..
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY
HIGH PRESSURE AT THE SURFACE MIGRATING THROUGH THE NORTHERN PLAINS
INTO THE UPPER MS VALLEY TO BRING NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES FROM SUNDAY NIGHT THROUGH WEDNESDAY. THROUGH THIS
PERIOD...MODELS IN GENERAL AGREEMENT FEATURING AN UPPER LEVEL
POSITIVE TILT LONG WAVE TROUGH TRANSITIONING EAST THROUGH THE CENTRAL
U.S....SUPPRESSING THE MAIN BAROCLINIC AXIS AND STORM TRACK WELL TO
THE SOUTHEAST. A WAVE OF LOW PRESSURE TRACKING ALONG THE OHIO RIVER
MONDAY WILL SPREAD SNOW INTO PORTIONS OF MO AND IL...AND WILL KEEP
ONLY SLIGHT CHANCE POPS CONFINED TO THE FAR EAST AND SOUTH MONDAY
NIGHT ON THE EXTREME NW EDGE OF THIS SYSTEM. OTHERWISE...NO
PRECIPITATION IS EXPECTED...BUT HIGH LEVEL LIFT AND MOISTURE ALOFT
AHEAD OF THE UPPER TROUGH AXIS WILL FAVOR MOSTLY CLOUDY SKIES FOR
MUCH OF MON THROUGH WED.
THU THROUGH SAT...MODEL CONSENSUS INDICATES A COLD FRONT DROPPING
SOUTH THROUGH THE REGION LATE THURSDAY...FOLLOWED BY MUCH COLDER
TEMPERATURES FRIDAY AND SATURDAY FOLLOWING A FRESH INFLUX OF COLD
AIR AT 850 MB THAT HAS BEEN BUILDING WELL TO THE NORTH. THERE
CONTINUES TO BE CONSIDERABLE DIFFERENCES WITH THE TIMING AND
PLACEMENT OF CRITICAL UPPER LEVEL TROUGHS AND SURFACE FEATURES IN
THIS TIME FRAME...THUS THE POTENTIAL FOR PRECIPITATION REMAINS LOW
CONFIDENCE. THE CURRENT SUITE OF MODELS USED IN THE EXTENDED
SUPPORTS OUR SLIGHT TO LOW END CHANCES FOR LIGHT SNOW FOR THU NIGHT
FOLLOWING THE PASSAGE OF THE COLD FRONT. AHEAD OF THIS FRONT...HIGHS
THURSDAY SHOULD REACH INTO THE 30S IN MOST AREAS. THIS IS FOLLOWED
BY 20S FRIDAY AND SATURDAY WITH OVERNIGHT LOWS IN THE SINGLE DIGITS
AND TEENS. ..SHEETS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1220 AM EST FRI DEC 2 2011
.SYNOPSIS...
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC REGION FROM THE WEST
TONIGHT THROUGH WEEKEND. A WEAK...DRY COLD FRONT WILL CROSS INTO
THE AREA FRIDAY NIGHT...BRINGING SLIGHTLY COOLER TEMPERATURES
SATURDAY. MILDER CONDITIONS RETURN FOR THE LATTER HALF OF THE
WEEKEND INTO EARLY NEXT WEEK AHEAD OF A SLOW MOVING COLD
FRONT...WHICH APPROACHES THE REGION FROM THE WEST BY THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
LATEST WX ANALYSIS DEPICTS ~1028MB SURFACE HIGH PRESSURE OVER
E KY/TN. ALOFT...TROUGH-RIDGE-TROUGH PATTERN EVIDENT ON RUC H5
ANALYSIS AS MID LEVEL TROUGHING HAS NOW TRANSITIONED OFF THE EAST
COAST...WITH LOW AMPLITUDE H5 RIDGING TO THE WEST OVER THE GULF
COAST/LOWER MS VALLEY...WITH CLOSED OFF/POSITIVELY TILTED UPPER
LEVEL LOW PRESSURE REMAINS IN PLACE OVER BAJA/SOUTHERN
CALIFORNIA.
BREEZY CONDITIONS STILL IN PLACE OVER MAINLY COASTAL ZONES THIS
AFTERNOON AS A RESULT OF PRESSURE GRADIENT BETWEEN DEPARTING MID
LEVEL TROUGH...AND HIGH PRESSURE TO THE WEST. COASTAL AREAS
SHOULD CONTINUE TO BE BREEZY (GUSTS TO 15-17 KT) FOR A FEW MORE
HOURS BEFORE DECOUPLING/RELAXING PRESSURE GRADIENT ALLOWS FOR
WINDS TO DROP OFF EARLY THIS EVENING. OTHERWISE...A MOSTLY CLEAR
AND PLEASANT LATE FALL AFTERNOON ACROSS THE CWA...MAXIMA WL AVERAGE
OUT INTO THE MID 50S INLAND...LOW TO MID 50S OVER COASTAL ZONES.
CLEAR SKIES/LIGHT WINDS PORTEND TO GOOD RADIATING CONDITIONS
TONIGHT. LOOKING FOR TEMPERATURES BE CLOSE TO/JUST BELOW LAST
NIGHTS/THIS MORNING`S LOWS. LOOK FOR LOWS INTO THE M-U 20S
INLAND...LOW TO MID 30S OVER COASTAL ZONES.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
LATE WEEK/WEEKEND TIME FRAME CHARACTERIZED BY SLOWLY BUILDING UPPER
LEVEL RIDGING WITH TIME OVER THE EASTERN CONUS...RESULTING IN
CONTINUED DRY WEATHER THROUGH THE PERIOD.
FRIDAY...
HIGH PRESSURE BECOMES ENTRENCHED OVER THE MID ATLANTIC
STATES THROUGH THE WEEKEND. AS A CUTOFF LOW DEVELOPS OVER THE
SOUTHWESTERN US...A WEAK UPPER LEVEL TROUGH WILL BECOME SEPARATED
FROM IT AND DRIFT ACROSS THE NORTHERN PLAINS/UPPER GREAT
LAKES...BEFORE SLOWLY PUSHING ACROSS NEW ENGLAND BY FRIDAY NIGHT.
THIS FEATURE WILL EVENTUALLY PUSH WEAK/DRY FRONTAL BOUNDARY TO OUR
NORTH THROUGH THE REGION LATE TOMORROW INTO SATURDAY WITH LITTLE
MORE THAN A FEW MID-HIGH CLOUDS PUSHING ACROSS THE AREA. MAXIMA
SLIGHTLY WARMER THAN TODAY`S VALUES...GENERALLY INTO THE M/U 50S
AREA WIDE...NEAR 60 WELL INLAND. SO WHILE WE CAN EXPECT A SLIGHTLY
MILDER EVENING FRIDAY NIGHT...HAVE SIDED CLOSER TO COOLER ENVELOPE
OF MAV GUIDANCE IN EXPECTATION OF LIGHT WINDS OVER LAND AND STILL
RELATIVELY SCANT MID LEVEL CLOUD COVER AS HIGH PRESSURE SLIDES
OVERHEAD. EARLY MORNING LOWS FRI NIGHT/SAT MORNING GENERALLY INTO
THE L-M30S TO NEAR 40 ALONG COASTAL ZONES.
SATURDAY...
THE SURFACE HIGH BECOMES POSITIVELY TILTED ON SATURDAY AS THE
RIDGE AXIS BEGINS TO SHIFT OFFSHORE. DESPITE AFOREMENTIONED
WARMING WITH TIME ALOFT AS SUBTROPICAL RIDGE BEGINS TO BUILD ACROSS
THE SOUTHEASTERN CONUS...TEMPERATURES WILL BE MODESTLY COOLER
SATURDAY DUE TO THE INFLUENCE OF MODIFYING ~1036MB SFC HIGH
PRESSURE PUSHING IN FROM THE WEST. AS WE`VE SEEN SEVERAL TIMES
ALREADY THIS FALL...LIMITED MIXING NOTED ON FORECAST SOUNDINGS FOR
SATURDAY (GENERALLY TO ~950-925MB) WILL KEEP TEMPERATURES A BIT
LOWER THAN LOCAL THICKNESS TOOLS AND WARMER MAV GUIDANCE DEPICT.
AS SUCH...HAVE GONE CLOSER TO COOLER MET VALUES FOR MAXIMA ON
SATURDAY WHICH YIELD SEASONABLE...ALBEIT SLIGHTLY COOLER...MAXIMA
INTO THE LOW TO MID 50S.
SATURDAY NIGHT/SUNDAY...
SURFACE HIGH PIVOTS TO THE MID-ATLANTIC/SE COAST AND THEN
OFFSHORE SAT NIGHT THROUGH SUNDAY...WITH DEVELOPING RETURN (SOUTH-
SOUTHEAST) FLOW AND CONTINUED BUILDING OF RIDGING ALOFT INITIATING
MODERATING TEMPERATURE TREND FOR SATURDAY NIGHT THROUGH THE EARLY
PORTION OF NEXT WEEK. LOOK FOR EARLY MORNING LOWS CONTINUED DRY
AND MILDER CONDITIONS SUNDAY WITH MAXIMA INTO THE L-M 60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
OVERALL PATTERN IN THE EXTENDED FAVORS A DOMINANT MID/UPPER LEVEL
RIDGE CENTERED FROM THE GULF OF MEXICO ENE ACRS FLORIDA AND TOWARDS
BERMUDA. MEANWHILE...A DEEP TROUGH OVER CENTRAL CANADA WILL
GRADUALLY PUSH SOUTH AND TAKE ON A POSITIVE TILT (OR EVEN BECOME
CUTOFF) OVER THE CENTRAL CONUS. THIS SETUP WILL BE VERY SLOW TO
CHANGE THROUGH THE MIDDLE OF NEXT WEEK...AND WILL KEEP BULK OF
PRECIPITATION OFF TO OUR WEST UNTIL WED. FOR THE MID ATLC AND SE
STATES...THIS WILL ALSO TRANSLATE INTO WELL ABOVE AVG TEMPERATURES
MON-TUE...AND POSSIBLY WED BEFORE COOLING DOWN TO AROUND AVG ON THU.
GIVEN THE CONTINUED MODEL DISCREPANCIES (LATEST ECMWF REMAINING
ABOUT 12-18 HRS SLOWER THAN THE GFS/GLOBAL GEM
ENSEMBLES....CONFIDENCE IN TUE-THU FCST IS LOWER THAN AVG.
AS WITH PREVIOUS FCST...HAVE GENLY BROAD-BRUSHED A LOW CHANCE POP
ACRS THE NW ZONES...TO DRY OR SLIGHT CHANCE ELSEWHERE FROM LATE MON
THROUGH TUE. WILL FOCUS HIGHEST POPS DURING THE DAY WED/WED EVENING
AS A BLEND OF MODEL TIMING PUSHES THE SFC COLD FRONT THROUGH.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR UFN AS HIGH PRES KEEPS SKIES CLEAR THRU FCST PERIOD. A DRY
FRONTAL BOUNDARY CROSSES THE AREA TONITE SHIFTING WINDS INTO THE
N-NE. VFR CONDITIONS CONT THRU THE WEEKEND.
&&
.MARINE...
NO FLAGS NEXT 12-18 HRS AS HIGH PRS BUILDS OVR THE WATERS KEEPING
CNDTNS BELOW SCA LVLS.
PVS DSCN:
ANOTHER BOUNDARY/COOL SURGE FRI NIGHT...WITH MARGINAL SCA EVENT
LIKELY ONCE AGAIN OVER THE BAY....AND POSSIBLE ON THE COASTAL
WATERS. AS THIS IS LATER 3RD PERIOD...HAVE DECIDED TO WAIT UNTIL
CURRENT HEADLINES END BEFORE RAISING ANOTHER SET (ALTHOUGH FCST
DOES INCLUDE SCA CONDITIONS). THIS SURGE IS FAIRLY BRIEF...AND
SHOULD END BY LATE SAT MORNING ASIDE FROM LINGERING 5 FT SEAS OVER
SOUTHERN COASTAL WATERS. OTHERWISE...BENIGN SAT EVENING THROUGH
MON AS HIGH PRESSURE SETTLES OVER THE REGION AHEAD OF THE NEXT
COLD FRONT. WINDS GRADUALLY TURN SOUTHERLY SUN-TUE BUT WIND SPEEDS
LOOK TO AVG 10-15 KT OR LESS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MAM
NEAR TERM...BKH/MAM
SHORT TERM...MAM/BMD
LONG TERM...LKB
AVIATION...MPR
MARINE...MPR/LKB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
440 AM EST FRI DEC 2 2011
.DISCUSSION...
A COLD MORNING WHERE IT HAS CLEARED OUT OVERNIGHT WITH MANY INTERIOR
SPOTS SEEING TEMPS IN THE SINGLE DIGITS UNDER HIGH PRESSURE AND LOW
PRECIPITABLE WATER VALUES OF AROUND 0.1 INCH. WOULD NOT BE SURPRISED
IF WE SEE A FEW TEMPS NEAR 0F NEAR THE WISCONSIN BORDER WITH DWPTS
JUST ABOVE 0 AT THIS TIME.
LAKE EFFECT CLOUDS ARE STARTING TO RETREAT TO THE NORTH AND EAST AS
HIGH PRESSURE RIDGING ACROSS THE UPPER MS VLY BUILDS ACROSS THE
AREA. EXPECT ANY REMAINING CLOUDS AND FLURRIES TO CLEAR OUT THIS MORNING
YIELDING A MOSTLY SUNNY DAY ACROSS THE AREA. UPPER HEIGHTS BUILD
RATHER QUICKLY TODAY WITH RATHER ABRUPT WARM ADVECTION DEVELOPING
THIS AFTERNOON AS THE WESTERN TROUGH SHIFTS EAST. IN FACT...BY 00Z
THIS EVENING 850MB TEMPS RISE TO -2C ACROSS THE WEST /FROM -12C THIS
MORNING/. SHOULD SEE A NICE RECOVERY IN TEMPS TODAY WITH ALL AREAS
WELL INTO THE UPPER 20S. DEVELOPING DOWNSLOPE S-SW FLOW THIS AFTN MAY
HELP TEMPS NEAR THE LAKESHORE TOP OUT IN THE LOWER 30S.
THE FORECAST BEGINS TO BECOME TRICKY STARTING LATER TONIGHT AND
CONTINUES TRICKY RIGHT THROUGH SUNDAY. STRONG SHORT WAVE ENERGY
CURRENTLY OVER BRITISH COLUMBIA WILL DIVE SOUTHEASTWARD TODAY. THIS
WILL CAUSE AN ALBERTA CLIPPER LIKE SYSTEM TO MOVE ACROSS THE UPPER
LAKES SATURDAY. A PIECE OF ENERGY WILL ALSO BREAK OFF FROM THIS
WAVE...DIVING DUE SOUTH DOWN THE INTERMOUNTAIN WEST HELPING TO EJECT
THE DEEP UPPER LOW OVER THE SOUTHWESTERN STATES TONIGHT INTO
SATURDAY. AS THE FRONT ASSOCIATED WITH THE NORTHERN LOW MOVES ACROSS
THE UPPER GREAT LAKES...GULF MOISTURE WILL STREAM NORTHWARD ALONG
THE FRONT ON SATURDAY. ALTHOUGH SYNOPTIC FORCING NOT BE TERRIBLY
STRONG...THERE WEAK ISENTROPIC LIFT DURING THE DAY ON SATURDAY
SHOULD ALLOW FOR LIGHT PRECIPITATION TO FALL ALONG AND EAST OF THE
FRONT. WITH THIS BEING SAID...HAVE OPTED TO MAINTAIN LIKELY POPS
DURING THE DAY ACROSS THE EASTERN HALF OF THE FORECAST AREA...WITH A
MINIMAL CHANCE FOR PRECIPITATION ACROSS WESTERN UPPER MICHIGAN WHERE
DRIER AIR AND MINIMAL ISENTROPIC LIFT WILL MINIMIZE ANY PCPN
CHANCES. AS FOR PRECIPITATION TYPE ON SATURDAY...EXPECT MOSTLY SNOW
TO FALL EXCEPT FOR AREAS CLOSE TO LAKE MICHIGAN WHERE BOUNDARY TEMPS
WITH SOUTHERLY FLOW SHOULD RISE ENOUGH TO KEEP IT ALL RAIN OR A
RAIN/SNOW MIX. WITH LACK OF SIGNIFICANT UPWARD MOTION...DO NOT
EXPECT ACCUMULATIONS TO AMOUNT TO MORE THAN AN INCH OR TWO WHERE IT
DOES SNOW THE LONGEST.
ALTHOUGH MODELS HAVE COME INTO BETTER AGREEMENT IN BRINGING A
SURFACE LOW ACROSS THE UPPER LAKES SATURDAY NIGHT INTO
SUNDAY...THERE ARE STILL SUBTLE DETAILS WHICH WILL MAKE THE SNOWFALL
FORECAST CHALLENGING. OVERALL...THE LOW TRACK IS BECOMING BETTER
DEFINED WITH A TRACK ACROSS LAKE MICHIGAN AND TO FAR EASTERN UPPER
MI BY SUN MORNING. IN ADDITION...WITH THE EXCEPTION OF THE GFS...THE
MODELS HAVE ALSO COME INTO BETTER AGREEMENT IN SHOWING A SWATH OF
MODERATE PRECIPITATION IN THE FORM OF SNOW TO MOVE ACROSS CENTRAL
UPPER MICHIGAN SAT NIGHT INTO SUNDAY MORNING DURING THE PERIOD OF
BEST FRONTOGENETIC FORCING COMBINED WITH REDUCED STABILITY ALOFT.
WITH THE EXCEPTION OF THE GFS...THE OTHER MODELS ARE IN FAIRLY GOOD
AGREEMENT IN SHOWING A SWATH OF .75 INCH OF PRECIPITATION SAT NIGHT
INTO SUNDAY MORNING. THIS MAKES SENSE GIVEN THE TRACK OF THE SFC AND
850MB LOW COMBINED WITH PRECIPITABLE WATER VALUES AROUND 0.5 INCH.
WITH THAT BEING SAID...HAVE RAISED POPS TO CATEGORICAL FOR THE
EASTERN PART OF THE FORECAST AREA SAT NIGHT INTO SUNDAY AND HAVE
GONE WITH STORM TOTAL SNOWFALL SAT NIGHT INTO SUNDAY OF 5-8 INCHES
MAINLY EAST OF A LANSE TO IRON RIVER LINE. DEPENDING ON THE EXACT
TRACK...MAY SEE SOME PRECIPITATION TYPE CONCERNS ACROSS EASTERN
UPPER AS WELL AS NEAR LAKE MICHIGAN...BUT ONLY IF THE NAM FORECAST
TRACK VERIFIES. ORIGINALLY WAS THINKING ABOUT GOING WITH A WINTER
STORM WATCH FOR PARTS OF CENTRAL UPPER MICHIGAN...BUT OPTED TO HOLD
OFF GIVEN THAT THE HEAVIEST SNOW WILL OCCUR AT NIGHT AND THE FACT
THAT THE STORM WILL MOVE THROUGH RATHER QUICKLY. STILL...FORECAST
AMOUNTS ARE VERY CLOSE TO WARNING CRITERIA AND GIVEN THAT THE SNOW
WILL BE WET IN NATURE /GENERALLY A 12-15:1 RATIO/...A WINTER STORM
WATCH MAY NEED TO BE ISSUED THIS AFTERNOON.
LES EXPECTED SUNDAY NIGHT...HOWEVER THE INTENSITY AND PLACEMENT WILL
DEPEND ON WHETHER ANOTHER WEAK LOW MOVES INTO THE AREA IN THE NW
FLOW AS THE GEM AND GFS SUGGEST. FOR NOW...HAVE OPTED TO GO WITH CHC
POPS NEAR THE LAKESHORE WITH THE HIGHEST POPS WEST.
FOR THE EXTENDED /MONDAY THROUGH THURSDAY/...
WITH SFC HIGH PRESSURE PUSHING IN FROM THE W AND A SFC TROUGH
EXTENDING FROM THE E OVER LAKE SUPERIOR...LOW LEVEL WINDS WILL
GENERALLY BE NW. AN UPPER TROUGH AXIS FROM FAR NERN CANADA TO THE
FAR SWRN CONUS WILL MOVE OVER THE CWA LATE MONDAY INTO TUESDAY. COOL
850MB TEMPS AOB -10C WILL EXIST UNDER THE TROUGH. THIS WILL RESULT
IN LAKE EFFECT SNOW IN NW WIND SNOWBELTS. THE BEST CHANCES FOR SNOW
WILL BE MONDAY...SINCE HIGH PRESSURE AND DRIER AIR WILL MOVE IN FROM
THE W MONDAY NIGHT.
THE SFC HIGH PRESSURE RIDGE WILL THEN PUSH EAST OF THE CWA LATE
TUESDAY...LEADING TO SW WINDS AHEAD OF A TROUGH OVER THE NRN PLAINS.
WITH THE SW WINDS AND 850MB TEMPS AOA -8C WED NIGHT...NO LAKE EFFECT
PRECIP IS EXPECTED.
WED WILL SEE BIG PATTERN CHANGES AS THE SFC TROUGH AND STRONG COLD
FRONT PASS THROUGH THE CWA. THE COOLEST AIR OF THE SEASON IS
INDICATED BY MODELS TO MOVE OVER THE AREA AS A DEEP LOW MOVE S TO
HUDSON BAY. THIS WILL BRING A DEEP...BROAD TROUGH ACROSS MOST OF THE
NRN CONUS WED AND THU. BEHIND THE SFC TROUGH...LOW LEVEL WINDS WILL
BE FROM THE NW AS 850MB TEMPS FALL TO AROUND -20C BY 06Z THU...AND
LOW LEVEL RH PLENTY SUFFICIENT FOR LAKE EFFECT PRECIP.
&&
.AVIATION /FOR 06Z TAF ISSUANCE/
WITH 900 MB TEMPS NEAR -11C...THERE IS CURRENTLY ENOUGH INSTABILITY
TO SUSTAIN LAKE CLOUDS. RUC 925-900 MB RH FCST AND RECENT TRENDS
SUGGEST THAT CLEARING WILL BE SLOW TO ADVANCE THIS EVENING...KEEPING
KIWD/KCMX NEAR THE EDGE OF THE CLOUD AREA. VFR CONDITIONS SHOULD
THEN PREVAIL THE REST OF THE NIGHT INTO FRI.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
A HIGH PRESSURE RIDGE OVER LAKE SUPERIOR WILL KEEP CONDITIONS ON THE
LAKE QUIET OVERNIGHT...WITH FLOW BEING GENERALLY NORTHWEST. THE
RIDGE WILL MOVE OUT BY THIS AFTERNOON. A LOW PRESSURE SYSTEM
CENTERED OVER MANITOBA WILL MOVE TO HUDSON BAY BY
SATURDAY...DRAGGING A TROUGH AND COLD FRONT ACROSS LAKE SUPERIOR
LATE SATURDAY. BETWEEN THE TWO SYSTEMS...THE PRESSURE GRADIENT WILL
STRENGTHEN. AS A RESULT...GALES TO 35-40 KNOTS ARE EXPECTED ON THE
LAKE FROM FRIDAY THROUGH SATURDAY MORNING. WESTERN LAKE SUPERIOR
WILL SEE THE START OF THE GALES FRIDAY AFTERNOON...AND ON FRIDAY
NIGHT THE EASTERN ZONES. ALL OF THE GALE FORCE WINDS SHOULD END
SATURDAY MORNING. WINDS WILL CONTINUE TO GUST TO AROUND 30 KNOTS
SATURDAY AFTERNOON...BEFORE DECREASING TO LESS THAN 25 KNOTS FOR THE
REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 10 AM EST SATURDAY FOR
LSZ266-267.
GALE WARNING FROM 10 AM EST /9 AM CST/ THIS MORNING TO 7 AM EST
/6 AM CST/ SATURDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
DISCUSSION...MRD
EXTENDED...TITUS
AVIATION...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1239 AM EST FRI DEC 2 2011
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.SHORT TERM...
FOR TONIGHT...LOW PRESSURE TROUGH RESPONSIBLE FOR LAST NIGHT AND
TODAYS SNOWFALL WILL MAKE ITS WAY FROM EASTERN UPPER MICHIGAN TO
QUEBEC OVERNIGHT. MEANWHILE...A RIDGE EXTENDING FROM HIGH PRESSURE
IN THE CENTRAL PLAINS WILL SETTLE IN OVER UPPER MICHIGAN...BRINGING
QUIETER CONDITIONS TO A MAJORITY OF THE CWA. MAIN CONCERN IS WHETHER
OR NOT LES WILL CONTINUE TO IMPACT EASTERN UPPER MICHIGAN THROUGH
THE NIGHT WITH THE INCOMING DRY AIR. AS OF 15Z...CONDITIONS ACROSS
MINNESOTA WERE DRYING OUT...WITH CLEAR SKIES AND LARGE DEWPOINT
DEPRESSIONS OBSERVED. 12Z SOUNDINGS AT INTERNATIONAL FALLS MN AND
PICKLE LAKE ONTARIO SHOW INVERTED V-TYPE SOUNDINGS...WITH INVERSION
HEIGHTS AROUND 3000 FEET. THIS DRYING WITH LOW INVERSION HEIGHTS
SUGGESTS THAT ANY LES ACCUMULATIONS OVERNIGHT IN THE EASTERN CWA
WILL BE SMALL...AND COVERAGE WILL BE LIMITED. CURRENTLY MOST CLOUD
COVER IS DIMINISHING ACROSS THE WESTERN CWA...WITH THE EXCEPTION OF
LAKE EFFECT CLOUDS. REGWRF...RUC...AND GFS ALL HINT AT A COUPLE OF
LES BANDS DEVELOPING EAST OF MARQUETTE...MOVING TOWARDS GRAND MARAIS
AND LASTING THROUGH THE NIGHT. SOME CLOUD BANDS ARE OBSERVED ON THE
VISIBLE SATELLITE AT THE MOMENT OVER EASTERN LAKE SUPERIOR...AND I
EXPECT THESE TO BECOME MORE ORGANIZED AFTER DARK. THE MAIN
DIFFERENCE OBSERVED BETWEEN EACH OF THE MODEL FIELDS IS THE AMOUNT
OF LINGERING MOISTURE...THE NAM PUSHES ALL OF THE MOISTURE OUT OF
THE REGION BY 00Z TONIGHT...WHICH PUTS THE END TO LES. THIS SEEMS TO
BE THE OUTLIER...HOWEVER. WITH THE WINDS OUT OF THE NORTHWEST THIS
EVENING...EXPECT SOME LIGHT LAKE EFFECT SNOW SHOWERS TO CONTINUE
FROM MARQUETTE MOVING EASTWARD THROUGH THE NIGHT AS THE DRIER AIR
WORKS IN. ANOTHER FAVORABLE FACTOR IS THAT LES TYPICALLY RAMPS UP
DURING THE NIGHT HOURS...AND AS A RESULT WILL KEEP IN SOME SHOWERS
EAST OF MARQUETTE. THIS LES SHOULD END BY EARLY MORNING HOWEVER...AS
WINDS BECOME WESTERLY...PUSHING ANY REMAINING BANDS INTO ONTARIO OR
ENDING THEM ALL TOGETHER. FOR THE WESTERN CWA ONLY HAVE LAKE INDUCED
CLOUD COVER LASTING THROUGH AROUND 6Z AS A RESULT OF THE NORTHWEST
WINDS...THEN TAPERING OFF AS THE WINDS SHIFT TO THE SOUTHWEST. CLOUD
COVER IN THE INTERIOR WEST TONIGHT...ALLOWING FOR DECENT RADIATIONAL
COOLING. AS A RESULT...TEMPERATURES NEAR THE WISCONSIN BORDER SHOULD
FALL INTO THE SINGLE DIGITS TONIGHT.
AS FOR FRIDAY...WITH THE HIGH PRESSURE RIDGE OVERHEAD AND THE DRY
AIRMASS IN PLACE...EXPECT A MOSTLY SUNNY DAY. TEMPERATURES WILL
STRUGGLE TO REACH INTO THE 30S INLAND AS A RESULT OF MORE STABLE
CONDITIONS. EXPECT WINDS TO INCREASE THROUGHOUT THE DAY AS PRESSURE
GRADIENT BETWEEN HIGH PRESSURE RIDGE AND A LOW PRESSURE SYSTEM
CENTERED OVER MANITOBA TIGHTENS.
.LONG TERM 00Z SAT ONWARD...
THE NAM SHOWS A 500 MB SHORTWAVE RIDGE OVER THE UPPER GREAT LAKES
00Z SAT WITH A TROUGH IN THE NORTHERN ROCKIES AND A CLOSED LOW AND
TROUGH IN THE DESERT SW 00Z SAT. THE TROUGH PULLS EAST INTO THE
NORTHERN PLAINS 00Z SUN WITH THE SOUTHERN TROUGH GETTING CUT OFF AND
REMAINING IN THE DESERT SW. NAM SHOWS SOME 850-500 MB Q-VECTOR
CONVERGENCE AND MOISTURE SAT INTO SUN MORNING. NAM ALSO SHOWING SOME
ISENTROPIC LIFT AND MOISTURE ON I280K-I295K SURFACES ON SAT BEFORE
THE LIFT MOVES OFF FOR SAT NIGHT INTO SUNDAY. GFS SHOWS SOME 850-500
MB Q-VECTOR CONVERGENCE MOVING THROUGH FRI NIGHT THROUGH SAT EVENING
BEFORE THIS MOVES OUT. STILL LOOKS LIKE A 3-6 INCH SNOW EVENT FOR
THE CWA WITH THE MOST SNOW IN THE CENTRAL CWA AND LESSER AMOUNTS IN
THE WEST AND EAST. THE EAST WOULD HAVE SOME RAIN MIXED IN AND THE
WEST WOULD BE ON THE WESTERN EDGE OF THE PCPN SHIELD. LAKE EFFECT
THEN TAKES OVER ON SUNDAY FOR NORTH AFFECTED LAKE EFFECT SNOW BELTS.
OVERALL DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES OR WEATHER.
IN THE EXTENDED...THE GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
NORTHERN PLAINS 00Z MON DOWN INTO THE SOUTHERN ROCKIES. THIS TROUGH
MOVES INTO THE UPPER GREAT LAKES 00Z TUE. THIS TROUGH THEN SPLITS
WITH THE NORTHERN PART OF THE TROUGH OVER THE LOWER GREAT LAKES
WHILE THE SOUTHERN PART IS OVER THE SOUTHERN PLAINS 00Z WED. A BROAD
TROUGH THEN SETS UP ACROSS THE NORTHERN U.S. 00Z THU ASSOCIATED WITH
THE CIRCUMPOLAR VORTEX OVER CENTRAL AND NORTHERN CANADA WITH THE
TROUGH AXIS REMAINING OFF TO THE WEST OF THE AREA 00Z FRI. WHAT THIS
WILL MEAN IS COLDER WEATHER IS ON THE WAY WITH LAKE EFFECT SNOW
BEING THE MAIN WEATHER TYPE FOR THIS FORECAST AND COLDER THAN NORMAL
TEMPERATURES. 850 MB TEMPERATURES GET DOWN TO -14C ON MONDAY INTO
TUESDAY WITH THE GFS WITH A WARMUP FOR WED...BEFORE A REINFORCING
SHOT OF COLD AIR ARRIVES FOR THU AS A COLD FRONT MOVES THROUGH.
OVERALL...DID NOT CHANGE MUCH EXCEPT TO BUMP UP POPS ON THURSDAY IN
LAKE EFFECT AREAS WITH THE COLDER AIR.
&&
.AVIATION /FOR 06Z TAF ISSUANCE/
WITH 900 MB TEMPS NEAR -11C...THERE IS CURRENTLY ENOUGH INSTABILITY
TO SUSTAIN LAKE CLOUDS. RUC 925-900 MB RH FCST AND RECENT TRENDS
SUGGEST THAT CLEARING WILL BE SLOW TO ADVANCE THIS EVENING...KEEPING
KIWD/KCMX NEAR THE EDGE OF THE CLOUD AREA. VFR CONDITIONS SHOULD
THEN PREVAIL THE REST OF THE NIGHT INTO FRI.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
HIGH PRESSURE RIDGE OVER LAKE SUPERIOR WILL KEEP CONDITIONS ON THE
LAKE QUIET OVERNIGHT...WITH FLOW BEING GENERALLY NORTHWEST. AS THE
RIDGE MOVES OUT...A LOW PRESSURE SYSTEM CENTERED OVER MANITOBA WILL
DRAG A TROUGH ACROSS LAKE SUPERIOR. AS IT PROGRESSES EASTWARD...THE
PRESSURE GRADIENT WILL STRENGTHEN. AS A RESULT...GALES TO 35-40
KNOTS ARE EXPECTED ON THE LAKE FROM FRIDAY THROUGH SATURDAY MORNING.
WESTERN LAKE SUPERIOR NEAR ISLE ROYALE AND NORTH CENTRAL LAKE
SUPERIOR WILL SEE THE START OF THE GALES FRIDAY AFTERNOON...AND ON
FRIDAY NIGHT THE EASTERN ZONES. ALL OF THE GALE FORCE WINDS SHOULD
END BY SATURDAY MORNING. WINDS WILL CONTINUE TO GUST TO AROUND 30
KNOTS SATURDAY AFTERNOON...BEFORE DECREASING TO LESS THAN 20 KNOTS
FOR THE REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 10 AM EST SATURDAY FOR
LSZ266-267.
GALE WARNING FROM 10 AM THIS MORNING TO 7 AM EST SATURDAY FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MCB
LONG TERM...07
AVIATION...TITUS
MARINE...MCB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
604 PM CST SAT DEC 3 2011
.DISCUSSION...
SNOW HAS BEGUN TO SRPEAD INTO S MN AND WILL CONTINUE TO EXPAND NE
RAPIDLY DURING THE REMAINDER OF THE AFTERNOON. A BIT OF SATURATION
LEFT TO DO IN LOWER LEVELS BUT CIGS ARE BEGINNING TO LOWER ACROSS
S MN. IR SATELLITE SHOWS ELONGATED VORT FROM W KS INTO SC NEB
LIFTING NE. GFS/NAM SIMILAR ON TIMING BRINGING MAIN VORT INTO SC MN
BY 00Z AND THEN LIFTING INTO CENTRAL WI BY 06Z. GFS HAS INCREASED
QPF VALUES A BIT MORE TOWARD THE NAM SOLUTION. INCREASED SNOW
AMOUNTS A BIT ACROSS AREAS FROM MKT TO SE METRO BASED LARGELY ON
TRACK OF SURFACE/850 MB LOW CENTERS. HEAVY SNOW OFTEN SETS UP 70
TO 90 MILES N OF 850 MB LOW TRACK..AND 850 MB LOW TRACKS FROM SW
IA TO JUST S OF LSE BY 06Z THEN INTO E UPR MICHIGAN BY 12Z. KEPT
SNOW AMOUNTS IN THE 3 TO 6 INCH ADVISORY. FAVORABLE ISENTROPIC
LIFT COMES THRU RATHER QUICKLY WITH 3-3.5G/KG SO HESITATE TO GO
ANY HIGHER. WILL BE A PERIOD FROM AROUND 22Z TO 05Z WHERE ADVISORY
AREA WILL BE UNDER STRONG UPPER DIVERENGE FROM COUPLED UPPER JET...
FAVORABLE DENDRITIC TEMPERATURES AND STRONG 600 MB FULL WIND
FRONTOGENSIS WHICH COULD BRING A PERIOD OF A FEW HOURS OF
VISIBILITY INTO THE 1/2 SM RANGE AS FAR N AS MSP. LIKE THE TIMING
OF THE RUC BUFKIT SNOW ACCUMS IN THAT WINDOW. DECREASED SNOW
AMOUNTS SLIGHTLY IN W SIDE OF ADVY AREA AROUND SPRINGFIELD AND
GAYLORD. ADVISORY WILL LIKELY BE ABLE TO BE EXPIRED BY 06Z ACROSS
MUCH OF THE MN CWA WITH NO SIGNIFICANT WIND EXPECTED IN WAKE OF
SNOW.
COOLER FOR SUNDAY...BUT TROF DROPPING OUT OF CANADA WILL BACK
WINDS ENUF TO KEEP MAIN PUSH OF COLD AIR NORTH OF AREA. AS THIS
SYSTEM MOVES THRU COLD AIR WILL MOVE IN FOR MONDAY WITH HIGHS ONLY
IN THE TEEN TO MID 20S. SLIGHT MODERATION FOR WEDNESDAY AS WEAK
TROF MOVES ACROSS AREAK. AFTER THAT AREA REMAINS IN COLD AND DRY
NW FLOW AT LEAST UNTIL NEXT WEEKEND.
WITH SNOW COVER EXPECTED TONIGHT ACROSS S MN INTO WC WI WILL BE SOME
SOME MORNINGS WHERE WE SHOULD GET MIN TEMPS DOWN NEAR
ZERO...TUESDAY AND PROBABLY AGAIN FRIDAY/SATURDAY.
.AVIATION.../00Z TAF ISSUANCE/
MAIN FORCING FOR SNOW WILL CONTINUE THROUGH EVENING FROM KMSP TO
THE EAST. KRNH TO KEAU LIKELY TO BE LIFR WITH VSBYS ONE HALF MILE
AND CIGS 002-003. AREAS FROM KMSP ON TO THE WEST..SNOW HAS
GENERALLY ENDED WITH MVFR TO LOW END VFR CIGS IN PLACE. SNOW
WINDING DOWN BY 06Z FROM KRNH TO KEAU WITH CIGS IMPROVING TO MVFR
BUT POSSIBLE MVFR VSBYS IN SNOW. THERE IS A CHANCE FOR MVFR CIGS
TO SCT OUT OVER MUCH OF THE MN TAF SITES BY MID MORNING
SUNDAY...BUT A SECONDARY TROUGH WITH COLDER AIR COULD BRING BACK
BKN VFR CIGS IN THE AFTERNOON...ESPECIALLY WEST CENTRAL MN.
KMSP... LAST BAND OF SIG SNOW TO MOVE THROUGH THE AREA FOR THE
NEXT HOUR TO HOUR AND A HALF AND THEN IMPROVING TO MVFR CIGS BUT
OCNL IFR VSBYS TO 2SM. SNOW GENERALLY ENDING BY 05Z BUT MVFR CIG
CONTINUING. CURRENTLY THINKING THAT LEVEL SHOULD REMAIN AT OR
ABOVE 017Z. MAY BE ENOUGH DRYING FOR SCT LOW CLOUDS 025-040 BY
SUNDAY AFTERNOON.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR ANOKA-BLUE
EARTH-BROWN-CARVER-CHISAGO-DAKOTA-FARIBAULT-FREEBORN-
GOODHUE-HENNEPIN-LE SUEUR-MARTIN-NICOLLET-RAMSEY-RICE-SCOTT-
SIBLEY-STEELE-WASECA-WASHINGTON-WATONWAN.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
BAP/JPR
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
729 AM EST FRI DEC 2 2011
.SYNOPSIS...
A QUICK-MOVING COLD FRONT WILL SWEEP THROUGH THE REGION TODAY
WITH SCATTERED TO NUMEROUS SNOW SHOWERS AND POSSIBLE SNOW
SQUALLS. THIS FRONT WILL BRING A POTENTIAL LIGHT SNOW
ACCUMULATION ACROSS NORTHERN NEW YORK LATE THIS MORNING INTO
EARLY THIS AFTERNOON...AND ACROSS NORTHERN VERMONT DURING THE
EARLY TO MID AFTERNOON HOURS. SKIES CLEAR TONIGHT WITH HIGH
PRESSURE BUILDING ACROSS THE NORTH COUNTRY. THIS WILL SET UP A
CHILLY NIGHT WITH LOWS IN THE TEENS TO LOWER 20S. HIGH PRESSURE
AND DRY WEATHER CONTINUE FOR THE WEEKEND WITH SEASONABLY COOL
TEMPERATURES ON SATURDAY MODERATING TO ABOVE NORMAL BY SUNDAY ON
GUSTY SOUTH WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 312 AM EST FRIDAY...MID-LEVEL CLOUDS ARE GRADUALLY
OVERSPREADING THE NORTH COUNTRY EARLY THIS MORNING IN ASSOCIATION
WITH UPSTREAM TROUGH AND COLD FRONT ACROSS SERN ONTARIO INTO
LOWER MICHIGAN. UPR TROUGH IS INITIALLY POSITIVE TILT...BUT
BECOMES MORE NEUTRAL TODAY AND SWINGS RAPIDLY THRU THE NORTH
COUNTRY AS A RATHER VIGOROUS WAVE THIS AFTN. NOT MUCH CHANGE FROM
PREVIOUS FCST...WITH BEST THREAT FOR SNOW SHOWERS FROM 14-17Z IN
THE SAINT LAWRENCE VALLEY...16-19Z IN THE ADIRONDACKS...17-21Z IN
THE CHAMPLAIN VALLEY...AND 18-22Z ACROSS THE REST OF VERMONT. THE
SNOW SHOWERS MAY BEGIN AS SOME LIGHT RAIN/SNOW IN THE VALLEY
LOCATIONS WITH SURFACE TEMPERATURES CLOSE TO 40 DEGREES...BUT
SHOULD CHANGE OVER TO SNOW AS THE PRECIPITATION CONTINUES TO
FALL. NARROW AREAS OF 35-40 DBZ MODEL REFLECTIVITY INDICATED IN
3-KM HRRR AND 4-KM LOCAL WRF RUN ASSOCIATED WITH POSSIBLE SNOW
SQUALL ACTIVITY. NOT MUCH SFC BASED INSTABILITY...BUT STEEP LAPSE
RATES AND STRONG DEEP- LAYER VORTICITY ADVECTION COULD BE
SUFFICIENT TO ORGANIZE BAND OF SNOW SQUALLS ACROSS NRN NY INTO
NRN VT TODAY. GREATEST COVERAGE OF SNOW SHOWERS WILL LIKELY BE
ACROSS NORTHERN NEW YORK AND INTO THE HIGHER ELEVATIONS OF
NORTHERN VERMONT. ACCUMULATIONS WILL BE LIGHT...GENERALLY LESS
THAN AN INCH...ALTHOUGH SOME OF THE HIGHER ELEVATIONS OF THE
GREEN MOUNTAINS COULD SEE UP TO 2 INCHES. THIS MAY ACCUMULATE
QUICKLY IN ANY SQUALLS...AND RESULT IN SLOW TRAVEL CONDITIONS FOR
A BRIEF TIME WITH LOW VSBY. HAVE HIGHLIGHTED THREAT IN THE
HAZARDOUS WEATHER OUTLOOK. HIGH TEMPERATURES WILL BE REACHED
BEFORE THE ONSET OF PRECIPITATION...GENERALLY MID TO UPPER
30S...WITH SOME LOW 40S IN THE CHAMPLAIN VALLEY. TEMPERATURES
WILL FALL QUICKLY WITH ONSET OF PCPN THROUGH THE 30S...AND INTO
THE 20S AFTER THE PASSAGE OF THE FRONT. THERE COULD ALSO BE A
PERIOD OF GUSTY NORTHWEST WINDS AFTER THE PASSAGE OF THE COLD
FRONT LATE FRIDAY AFTERNOON AND EVENING WITH SOME GUSTS 15-30
MPH.
CLEARING SKIES AND LIGHTER WINDS TONIGHT WITH STRONG SFC
ANTICYCLONE CRESTING OVER THE NORTH COUNTRY AT 12Z SATURDAY. LOW
TEMPERATURES GENERALLY IN THE TEENS...EXCEPT LOW 20S IN THE
CHAMPLAIN VALLEY. COULD SEE AN ISOLD READING IN THE UPR SINGLE
DIGITS IN THE NRN ADIRONDACKS...INCLUDING AT KSLK.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 312 AM EST FRIDAY...RIDGE OF HIGH PRESSURE IN PLACE FOR
SATURDAY...AND FEATURE WILL TRANSLATE SLOWLY EASTWARD TO THE GULF
OF MAINE LATE IN THE DAY. THIS WILL ALLOW AIR MASS TO MODERATE
WITH DEVELOPING SOUTH WINDS 5-10 MPH BY AFTN. LOOKING AT DRY
WEATHER...MOSTLY SUNNY SKIES AND SEASONABLE HIGH TEMPS FOR EARLY
DECEMBER IN THE MID-UPR 30S.
SOUTH TO SOUTHWEST GRADIENT FLOW PICKS UP SATURDAY NIGHT AND
ESPECIALLY ON SUNDAY. THESE WINDS AND PASSING MID-UPR CLOUDS WILL
KEEP LOW TEMPERATURES A BIT MILDER FOR SATURDAY NIGHT...AND THEN
TEMPS REBOUNDING INTO THE UPR 40S FOR SUNDAY. SOUTH WINDS COULD
BE RATHER GUSTY SUNDAY...GENERALLY 15-25 MPH WITH GUSTS TO 35 MPH
POSSIBLE PER 00Z NAM MODEL SOUNDINGS. A COLD FRONT WILL BE MOVING
EWD THRU THE GREAT LAKES REGION LATE IN THE DAY. AT THIS TIME
HELD OFF ON ANY PRECIPITATION ASSOCIATED WITH THIS
FEATURE...THOUGH CLOUDS WILL BE ON THE INCREASE LATE SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 345 AM EST FRIDAY...LOW PRESSURE SITUATED TO OUR WEST ON
SUNDAY EVENING WILL LIFT NORTH INTO CANADA OVERNIGHT...WEAK COLD
FRONT ASSOCIATED WITH THIS LOW WILL CROSS OUR REGION THOUGH
LIMITED MOISTURE ASSOCIATED WITH THIS FEATURE SO WILL ONLY
MENTION CHANCE POPS AT THIS TIME. AFOREMENTIONED FRONT WILL STALL
OUT TO SOUTHEAST AND SEVERAL WAVES OF MOISTURE WILL RIDE ALONG
THIS FRONT BRINGING MORE PRECIPITATION TO THE REGION. THE GFS AND
ECMWF BOTH SHOW THIS SCENARIO...BUT THE GFS SHOWS IT ENDING
SOONER THAN THE ECMWF. THE ECMWF HANGS ONTO THE PRECIP ALL THE
WAY THROUGH THURSDAY AND THE GFS ENDS THE PRECIP ON TUESDAY
NIGHT. AT THIS TIME HAVE MENTIONED HIGHEST POPS FOR MONDAY NIGHT.
TEMPERATURES WILL CONTINUE TO RUN WARMER THAN NORMAL THROUGH THE
PERIOD. RIGHT NOW LOOKS LIKE THE MAJORITY OF THE PRECIP WE GET
NEXT WEEK WILL BE RAIN WITH A POSSIBLE CHANGEOVER TO SNOW AT THE
END OF THE EVENT.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
THROUGH 12Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH 15Z
FRIDAY...AS A RIDGE OF HIGH PRESSURE SLOWLY MOVES EAST OF THE
REGION...WITH SOME AREAS OF MVFR CEILINGS ACROSS NORTHERN NEW
YORK. AN UPPER TROUGH WILL APPROACH THE REGION DURING THE DAY
TODAY. EXPECTING AREAS OF IFR/MVFR IN LIGHT SNOW DEVELOPING
ACROSS NORTHERN NEW YORK BETWEEN 16Z-18Z FRIDAY...AND THEN MOVING
INTO VERMONT BETWEEN 19Z-21Z FRIDAY. WINDS WILL BE GUSTY WITH
POSSIBLE SNOW SQUALLS DURING THIS TIME PERIOD ALSO. CONDITIONS
WILL CLEAR UP BY ABOUT 00Z AND VFR RETURNS...CLEAR SKIES AND
LIGHT WINDS ARE EXPECTED OVERNIGHT. .
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...MAINLY VFR CONDITIONS
EXPECTED THROUGH THE PERIOD...AS A RIDGE OF HIGH PRESSURE WILL BE
OVER THE REGION. SOME GUSTY SOUTHERLY WINDS ARE POSSIBLE ON
SUNDAY DURING THE DAYTIME HOURS. AREAS OF MVFR/IFR CONDITIONS
POSSIBLE IN RAIN AND SNOW SHOWERS MONDAY AND TUESDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...NEILES
AVIATION...NEILES
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
352 AM EST FRI DEC 2 2011
.SYNOPSIS...
A QUICK-MOVING COLD FRONT WILL SWEEP THROUGH THE REGION TODAY
WITH SCATTERED TO NUMEROUS SNOW SHOWERS AND POSSIBLE SNOW
SQUALLS. THIS FRONT WILL BRING A POTENTIAL LIGHT SNOW
ACCUMULATION ACROSS NORTHERN NEW YORK LATE THIS MORNING INTO
EARLY THIS AFTERNOON...AND ACROSS NORTHERN VERMONT DURING THE
EARLY TO MID AFTERNOON HOURS. SKIES CLEAR TONIGHT WITH HIGH
PRESSURE BUILDING ACROSS THE NORTH COUNTRY. THIS WILL SET UP A
CHILLY NIGHT WITH LOWS IN THE TEENS TO LOWER 20S. HIGH PRESSURE
AND DRY WEATHER CONTINUE FOR THE WEEKEND WITH SEASONABLY COOL
TEMPERATURES ON SATURDAY MODERATING TO ABOVE NORMAL BY SUNDAY ON
GUSTY SOUTH WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 312 AM EST FRIDAY...MID-LEVEL CLOUDS ARE GRADUALLY
OVERSPREADING THE NORTH COUNTRY EARLY THIS MORNING IN ASSOCIATION
WITH UPSTREAM TROUGH AND COLD FRONT ACROSS SERN ONTARIO INTO
LOWER MICHIGAN. UPR TROUGH IS INITIALLY POSITIVE TILT...BUT
BECOMES MORE NEUTRAL TODAY AND SWINGS RAPIDLY THRU THE NORTH
COUNTRY AS A RATHER VIGOROUS WAVE THIS AFTN. NOT MUCH CHANGE FROM
PREVIOUS FCST...WITH BEST THREAT FOR SNOW SHOWERS FROM 14-17Z IN
THE SAINT LAWRENCE VALLEY...16-19Z IN THE ADIRONDACKS...17-21Z IN
THE CHAMPLAIN VALLEY...AND 18-22Z ACROSS THE REST OF VERMONT. THE
SNOW SHOWERS MAY BEGIN AS SOME LIGHT RAIN/SNOW IN THE VALLEY
LOCATIONS WITH SURFACE TEMPERATURES CLOSE TO 40 DEGREES...BUT
SHOULD CHANGE OVER TO SNOW AS THE PRECIPITATION CONTINUES TO
FALL. NARROW AREAS OF 35-40 DBZ MODEL REFLECTIVITY INDICATED IN
3-KM HRRR AND 4-KM LOCAL WRF RUN ASSOCIATED WITH POSSIBLE SNOW
SQUALL ACTIVITY. NOT MUCH SFC BASED INSTABILITY...BUT STEEP LAPSE
RATES AND STRONG DEEP- LAYER VORTICITY ADVECTION COULD BE
SUFFICIENT TO ORGANIZE BAND OF SNOW SQUALLS ACROSS NRN NY INTO
NRN VT TODAY. GREATEST COVERAGE OF SNOW SHOWERS WILL LIKELY BE
ACROSS NORTHERN NEW YORK AND INTO THE HIGHER ELEVATIONS OF
NORTHERN VERMONT. ACCUMULATIONS WILL BE LIGHT...GENERALLY LESS
THAN AN INCH...ALTHOUGH SOME OF THE HIGHER ELEVATIONS OF THE
GREEN MOUNTAINS COULD SEE UP TO 2 INCHES. THIS MAY ACCUMULATE
QUICKLY IN ANY SQUALLS...AND RESULT IN SLOW TRAVEL CONDITIONS FOR
A BRIEF TIME WITH LOW VSBY. HAVE HIGHLIGHTED THREAT IN THE
HAZARDOUS WEATHER OUTLOOK. HIGH TEMPERATURES WILL BE REACHED
BEFORE THE ONSET OF PRECIPITATION...GENERALLY MID TO UPPER
30S...WITH SOME LOW 40S IN THE CHAMPLAIN VALLEY. TEMPERATURES
WILL FALL QUICKLY WITH ONSET OF PCPN THROUGH THE 30S...AND INTO
THE 20S AFTER THE PASSAGE OF THE FRONT. THERE COULD ALSO BE A
PERIOD OF GUSTY NORTHWEST WINDS AFTER THE PASSAGE OF THE COLD
FRONT LATE FRIDAY AFTERNOON AND EVENING WITH SOME GUSTS 15-30
MPH.
CLEARING SKIES AND LIGHTER WINDS TONIGHT WITH STRONG SFC
ANTICYCLONE CRESTING OVER THE NORTH COUNTRY AT 12Z SATURDAY. LOW
TEMPERATURES GENERALLY IN THE TEENS...EXCEPT LOW 20S IN THE
CHAMPLAIN VALLEY. COULD SEE AN ISOLD READING IN THE UPR SINGLE
DIGITS IN THE NRN ADIRONDACKS...INCLUDING AT KSLK.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 312 AM EST FRIDAY...RIDGE OF HIGH PRESSURE IN PLACE FOR
SATURDAY...AND FEATURE WILL TRANSLATE SLOWLY EASTWARD TO THE GULF
OF MAINE LATE IN THE DAY. THIS WILL ALLOW AIR MASS TO MODERATE
WITH DEVELOPING SOUTH WINDS 5-10 MPH BY AFTN. LOOKING AT DRY
WEATHER...MOSTLY SUNNY SKIES AND SEASONABLE HIGH TEMPS FOR EARLY
DECEMBER IN THE MID-UPR 30S.
SOUTH TO SOUTHWEST GRADIENT FLOW PICKS UP SATURDAY NIGHT AND
ESPECIALLY ON SUNDAY. THESE WINDS AND PASSING MID-UPR CLOUDS WILL
KEEP LOW TEMPERATURES A BIT MILDER FOR SATURDAY NIGHT...AND THEN
TEMPS REBOUNDING INTO THE UPR 40S FOR SUNDAY. SOUTH WINDS COULD
BE RATHER GUSTY SUNDAY...GENERALLY 15-25 MPH WITH GUSTS TO 35 MPH
POSSIBLE PER 00Z NAM MODEL SOUNDINGS. A COLD FRONT WILL BE MOVING
EWD THRU THE GREAT LAKES REGION LATE IN THE DAY. AT THIS TIME
HELD OFF ON ANY PRECIPITATION ASSOCIATED WITH THIS
FEATURE...THOUGH CLOUDS WILL BE ON THE INCREASE LATE SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 345 AM EST FRIDAY...LOW PRESSURE SITUATED TO OUR WEST ON
SUNDAY EVENING WILL LIFT NORTH INTO CANADA OVERNIGHT...WEAK COLD
FRONT ASSOCIATED WITH THIS LOW WILL CROSS OUR REGION THOUGH
LIMITED MOISTURE ASSOCIATED WITH THIS FEATURE SO WILL ONLY
MENTION CHANCE POPS AT THIS TIME. AFOREMENTIONED FRONT WILL STALL
OUT TO SOUTHEAST AND SEVERAL WAVES OF MOISTURE WILL RIDE ALONG
THIS FRONT BRINGING MORE PRECIPITATION TO THE REGION. THE GFS AND
ECMWF BOTH SHOW THIS SCENARIO...BUT THE GFS SHOWS IT ENDING
SOONER THAN THE ECMWF. THE ECMWF HANGS ONTO THE PRECIP ALL THE
WAY THROUGH THURSDAY AND THE GFS ENDS THE PRECIP ON TUESDAY
NIGHT. AT THIS TIME HAVE MENTIONED HIGHEST POPS FOR MONDAY NIGHT.
TEMPERATURES WILL CONTINUE TO RUN WARMER THAN NORMAL THROUGH THE
PERIOD. RIGHT NOW LOOKS LIKE THE MAJORITY OF THE PRECIP WE GET
NEXT WEEK WILL BE RAIN WITH A POSSIBLE CHANGEOVER TO SNOW AT THE
END OF THE EVENT.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
THROUGH 06Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH 15Z
FRIDAY...AS A RIDGE OF HIGH PRESSURE SLOWLY MOVES EAST OF THE
REGION...WITH SOME AREAS OF MVFR CEILINGS ACROSS NORTHERN NEW
YORK. AN UPPER TROUGH WILL APPROACH THE REGION DURING THE DAY
TODAY. EXPECTING AREAS OF IFR/MVFR IN LIGHT SNOW DEVELOPING
ACROSS NORTHERN NEW YORK BETWEEN 16Z-18Z FRIDAY...AND THEN MOVING
INTO VERMONT BETWEEN 19Z-21Z FRIDAY. CONDITIONS WILL CLEAR UP BY
ABOUT 00Z AND VFR RETURNS.
OUTLOOK 06Z SATURDAY THROUGH TUESDAY...MAINLY VFR CONDITIONS
EXPECTED THROUGH THE PERIOD...AS A RIDGE OF HIGH PRESSURE WILL BE
OVER THE REGION. SOME GUSTY SOUTHERLY WINDS ARE POSSIBLE ON
SUNDAY DURING THE DAYTIME HOURS. AREAS OF MVFR/IFR CONDITIONS
POSSIBLE IN RAIN AND SNOW SHOWERS MONDAY AND TUESDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...NEILES
AVIATION...NEILES
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
337 AM EST FRI DEC 2 2011
.SYNOPSIS...
A QUICK-MOVING COLD FRONT WILL SWEEP THROUGH THE REGION TODAY
WITH SCATTERED TO NUMEROUS SNOW SHOWERS AND POSSIBLE SNOW SQUALLS.
THIS FRONT WILL BRING A POTENTIAL LIGHT SNOW ACCUMULATION ACROSS
NORTHERN NEW YORK LATE THIS MORNING INTO EARLY THIS
AFTERNOON...AND ACROSS NORTHERN VERMONT DURING THE EARLY TO MID
AFTERNOON HOURS. SKIES CLEAR TONIGHT WITH HIGH PRESSURE BUILDING
ACROSS THE NORTH COUNTRY. THIS WILL SET UP A CHILLY NIGHT WITH
LOWS IN THE TEENS TO LOWER 20S. HIGH PRESSURE AND DRY WEATHER
CONTINUE FOR THE WEEKEND WITH SEASONABLY COOL TEMPERATURES ON
SATURDAY MODERATING TO ABOVE NORMAL BY SUNDAY ON GUSTY SOUTH
WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 312 AM EST FRIDAY...MID-LEVEL CLOUDS ARE GRADUALLY
OVERSPREADING THE NORTH COUNTRY EARLY THIS MORNING IN ASSOCIATION
WITH UPSTREAM TROUGH AND COLD FRONT ACROSS SERN ONTARIO INTO LOWER
MICHIGAN. UPR TROUGH IS INITIALLY POSITIVE TILT...BUT BECOMES MORE
NEUTRAL TODAY AND SWINGS RAPIDLY THRU THE NORTH COUNTRY AS A
RATHER VIGOROUS WAVE THIS AFTN. NOT MUCH CHANGE FROM PREVIOUS
FCST...WITH BEST THREAT FOR SNOW SHOWERS FROM 14-17Z IN THE SAINT
LAWRENCE VALLEY...16-19Z IN THE ADIRONDACKS...17-21Z IN THE
CHAMPLAIN VALLEY...AND 18-22Z ACROSS THE REST OF VERMONT. THE SNOW
SHOWERS MAY BEGIN AS SOME LIGHT RAIN/SNOW IN THE VALLEY LOCATIONS WITH
SURFACE TEMPERATURES CLOSE TO 40 DEGREES...BUT SHOULD CHANGE OVER
TO SNOW AS THE PRECIPITATION CONTINUES TO FALL. NARROW AREAS OF
35-40 DBZ MODEL REFLECTIVITY INDICATED IN 3-KM HRRR AND 4-KM LOCAL
WRF RUN ASSOCIATED WITH POSSIBLE SNOW SQUALL ACTIVITY. NOT MUCH
SFC BASED INSTABILITY...BUT STEEP LAPSE RATES AND STRONG DEEP-
LAYER VORTICITY ADVECTION COULD BE SUFFICIENT TO ORGANIZE BAND OF
SNOW SQUALLS ACROSS NRN NY INTO NRN VT TODAY. GREATEST COVERAGE OF
SNOW SHOWERS WILL LIKELY BE ACROSS NORTHERN NEW YORK AND INTO THE
HIGHER ELEVATIONS OF NORTHERN VERMONT. ACCUMULATIONS WILL BE
LIGHT...GENERALLY LESS THAN AN INCH...ALTHOUGH SOME OF THE HIGHER
ELEVATIONS OF THE GREEN MOUNTAINS COULD SEE UP TO 2 INCHES. THIS
MAY ACCUMULATE QUICKLY IN ANY SQUALLS...AND RESULT IN SLOW TRAVEL
CONDITIONS FOR A BRIEF TIME WITH LOW VSBY. HAVE HIGHLIGHTED THREAT
IN THE HAZARDOUS WEATHER OUTLOOK. HIGH TEMPERATURES WILL BE
REACHED BEFORE THE ONSET OF PRECIPITATION...GENERALLY MID TO UPPER
30S...WITH SOME LOW 40S IN THE CHAMPLAIN VALLEY. TEMPERATURES WILL
FALL QUICKLY WITH ONSET OF PCPN THROUGH THE 30S...AND INTO THE 20S
AFTER THE PASSAGE OF THE FRONT. THERE COULD ALSO BE A PERIOD OF
GUSTY NORTHWEST WINDS AFTER THE PASSAGE OF THE COLD FRONT LATE
FRIDAY AFTERNOON AND EVENING WITH SOME GUSTS 15-30 MPH.
CLEARING SKIES AND LIGHTER WINDS TONIGHT WITH STRONG SFC
ANTICYCLONE CRESTING OVER THE NORTH COUNTRY AT 12Z SATURDAY. LOW
TEMPERATURES GENERALLY IN THE TEENS...EXCEPT LOW 20S IN THE
CHAMPLAIN VALLEY. COULD SEE AN ISOLD READING IN THE UPR SINGLE
DIGITS IN THE NRN ADIRONDACKS...INCLUDING AT KSLK.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 312 AM EST FRIDAY...RIDGE OF HIGH PRESSURE IN PLACE FOR
SATURDAY...AND FEATURE WILL TRANSLATE SLOWLY EASTWARD TO THE GULF
OF MAINE LATE IN THE DAY. THIS WILL ALLOW AIR MASS TO MODERATE
WITH DEVELOPING SOUTH WINDS 5-10 MPH BY AFTN. LOOKING AT DRY
WEATHER...MOSTLY SUNNY SKIES AND SEASONABLE HIGH TEMPS FOR EARLY
DECEMBER IN THE MID-UPR 30S.
SOUTH TO SOUTHWEST GRADIENT FLOW PICKS UP SATURDAY NIGHT AND
ESPECIALLY ON SUNDAY. THESE WINDS AND PASSING MID-UPR CLOUDS WILL
KEEP LOW TEMPERATURES A BIT MILDER FOR SATURDAY NIGHT...AND THEN
TEMPS REBOUNDING INTO THE UPR 40S FOR SUNDAY. SOUTH WINDS COULD BE
RATHER GUSTY SUNDAY...GENERALLY 15-25 MPH WITH GUSTS TO 35 MPH
POSSIBLE PER 00Z NAM MODEL SOUNDINGS. A COLD FRONT WILL BE MOVING
EWD THRU THE GREAT LAKES REGION LATE IN THE DAY. AT THIS TIME HELD
OFF ON ANY PRECIPITATION ASSOCIATED WITH THIS FEATURE...THOUGH
CLOUDS WILL BE ON THE INCREASE LATE SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 334 PM EST THURSDAY...AREA OF HIGH PRESSURE MOVES INTO THE
GULF OF MAINE AND THE REGION GETS INTO SOUTHWESTERLY WARM
ADVECTION REGIME. WARMING 850MB TEMPS AND INCREASING CLOUDS
SUNDAY...WITH SLIGHT CHANCE SHOWERS TRENDING IN AREAL COVERAGE
FROM WEST TO EAST LATER SUNDAY INTO SUNDAY NIGHT. HIGHS ON SUNDAY
IN THE MID/UPPER 40S...THOUGH THESE COULD BE CLOSER TO 50 DEGREES
IF FULL MIXING OCCURS. CLOUDY SKIES WILL LIMIT DEGREE OF
NOCTURNAL COOLING SUNDAY NIGHT...WITH LOWS IN THE 30S.
WHILE THE GFS AND ECWMF EXTENDED RANGE DATA SHOW A CLOUDY AND WET
WEATHER PATTERN FOR THE EARLY TO MIDDLE PART OF NEXT WEEK...THERE
STILL ARE DIFFERENCES ON SPECIFIC DETAILS. AN AREA OF LOW
PRESSURE ON MONDAY WILL BRING CHANCE RAIN OR HIGHER TERRAIN SNOW
SHOWERS TO THE NORTH COUNTRY. THE BAROCLINIC ZONE ASSOCIATED WITH
THE STORM ON MONDAY LINGERS ACROSS THE REGION THROUGH TUESDAY AND
WEDNESDAY WITH CONTINUED CHANCES FOR PRECIPITATION AS WAVES OF
LOW PRESSURE MOVE NORTHEASTWARD ALONG IT. RECENT SOLUTIONS HAVE
TRENDED WARMER THROUGH PARTS OR ALL OF THIS EVENT. HAVE KEPT
CHANCE PRECIPITATION PROBABILITIES FOR RAIN OR SNOW SHOWERS GOING
THOUGH MIDWEEK BEFORE TAPERING PRECIPITATION PROBABILITIES DOWN
BY LATE WEEK. TEMPERATURES WILL CONTINUE TO RUN ABOVE AVERAGE
THROUGH THE PERIOD.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
THROUGH 06Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH 15Z
FRIDAY...AS A RIDGE OF HIGH PRESSURE SLOWLY MOVES EAST OF THE
REGION...WITH SOME AREAS OF MVFR CEILINGS ACROSS NORTHERN NEW
YORK. AN UPPER TROUGH WILL APPROACH THE REGION DURING THE DAY
TODAY. EXPECTING AREAS OF IFR/MVFR IN LIGHT SNOW DEVELOPING
ACROSS NORTHERN NEW YORK BETWEEN 16Z-18Z FRIDAY...AND THEN MOVING
INTO VERMONT BETWEEN 19Z-21Z FRIDAY. CONDITIONS WILL CLEAR UP BY
ABOUT 00Z AND VFR RETURNS.
OUTLOOK 06Z SATURDAY THROUGH TUESDAY...MAINLY VFR CONDITIONS
EXPECTED THROUGH THE PERIOD...AS A RIDGE OF HIGH PRESSURE WILL BE
OVER THE REGION. SOME GUSTY SOUTHERLY WINDS ARE POSSIBLE ON
SUNDAY DURING THE DAYTIME HOURS. AREAS OF MVFR/IFR CONDITIONS
POSSIBLE IN RAIN AND SNOW SHOWERS MONDAY AND TUESDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...LOCONTO
AVIATION...NEILES
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
353 PM EST FRI DEC 2 2011
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO PENNSYLVANIA TONIGHT AND CONTROL THE
LOCAL WEATHER UNTIL COLD FRONT MOVES IN FROM THE NORTHWEST EARLY
NEXT WEEK. THE COLD FRONT WILL MOST LIKELY STALL OVER THE STATE
AND LEAD TO RAIN FOR THE FIRST HALF OF THE WEEK. COLDER TEMPERATURES
WITH SCATTERED SNOW SHOWERS WILL THEN ENSUE IN THE MID WEEK.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
MID DECK ROLLING ACROSS THE AREA CURRENTLY WILL SLIDE TO THE EAST
AND DISSIPATE SOME AS IT DOES SO. MOST LOCATIONS WILL STAY FAIR
ALL EVENING. NEAR TERM GUID PORTRAYS THE LOW CLOUDS OVER THE
NORTHWEST LASTING FOR ONLY A FEW HOURS THIS EVENING...WITH JUST A
FLURRY OR TWO IN THE NW. HRRR PAINTS SOME FLURRIES IN THE
SW/LAURELS...BUT WILL NOT MENTION AT THIS POINT. GUSTY WNW WINDS
IN THE MTS WILL DIE DOWN QUICKLY THIS EVENING AS THE HIGH PRESSURE
BUILDS IN FROM THE WEST.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH SATURDAY NIGHT/...
CLEAR AND CALM FOR THE OVERNIGHT WITH AXIS OF SFC HIGH PRESSURE
OVERHEAD BEFORE SUNRISE. SOME OF THE COLDEST TEMPERATURES SO FAR
THIS YEAR. STILL LOOKING AT MINS AROUND 20F NEAR THE NEW YORK
BORDER...BUT WOULD NOT BE SURPRISED TO SEE READINGS DROP INTO THE
MID TEENS IN SOME OF THE NORMALLY COLDER SHELTERED VALLEY SPOTS.
LLVL FLOW GOES S/SERLY DURING THE DAY SAT...AND TEMPS SHOULD
RISE BACK TO NEAR NORMALS AFTER THE COLD START. CLOUDS WILL BE
TOUGH TO FIND EARLY...BUT HIGH CLOUDS FROM WARM ADVECTION ALOFT
WILL SHOW UP AS THE DAY CONTINUES. JUST P/C FOR SAT NIGHT WITH
SFC HIGH STRETCHED OUT ALL ALONG THE EAST COAST. 8H TEMPS RISE TO
+6C TO +8C BY SUN AM. DESPITE THIS...DECOUPLING WILL ALLOW THE
MINS TO DIP TO THE M/U20S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MAINLY DRY CONDITIONS WILL PERSIST INTO SUNDAY.
AN INCREASING SOUTHERLY BREEZE ON SUNDAY WILL HELP TO BOOST THE NEAR
TO SLIGHTLY BELOW NORMAL MAX TEMPS SATURDAY...TO A GOOD 5-7F ABOVE
NORMAL FOR SUNDAY. MAX TEMP DEPARTURES FROM NORMAL WILL BE GREATEST
ACROSS THE WRN MTNS WHERE HIGHS IN THE U40S TO LOWER 50S WILL BE 10F
OF MORE ABOVE NORMAL.
PARTLY TO MOSTLY SUNNY SKIES WILL BE FOUND ACROSS THE ERN HALF OF
THE STATE FOR MUCH OF SUNDAY...WHILE CLOUDS THICKEN UP ACROSS THE
WEST THROUGHOUT THE DAY. THERE WILL BE A CHANCE FOR A FEW SHOWERS
ACROSS THE FAR NW LATE.
PUSHED BACK THE ARRIVAL TIME OF THE RAIN SHIELD THROUGH THE
FORECAST AREA ON MONDAY AS LATEST GEFS HOLDS THE ANAMALOUS PWAT
VALUES BACK INTO OHIO INTO MONDAY. THAT WILL OVERSPREAD THE AREA
LATE MONDAY THROUGH TUESDAY AS THE FRONT CRAWLS ACROSS THE AREA.
INTRODUCED RAIN MIXING WITH AND CHANGING TO SNOW SHOWERS AS THE
COLD AIR MOVES IN TUESDAY NOGHT AND WEDNESDAY. THE TIMING OF THE
COLDER AIR ARRIVAL WITH THE EXITING PRECIP SHIELD WILL LIMIT ANY
APPRECIABLE ACCUMULATIONS.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
HIGH/MID CLOUD SHEET WILLDISSIPATE AS IT MOVES EAST THIS EVE...AND
THE LOW/MVFR ALMOST-IFR DECK IN THE NW WILL ALSO BREAK UP EARLY
TONIGHT. BY 03Z...IT SHOULD BE PRETTY MUCH CLEAR. THE CLEAR SKIES
WILL LAST INTO THE DAYTIME SAT...WITH ONLY HIGH CLOUDS FOR SAT
AFTN/NIGHT. GUSTY WINDS AT THIS TIME WILL DECREASE VERY RAPIDLY
THIS EVENING AS THE HIGH PRESSURE OFF TO THE WEST SETS UP
OVERHEAD. THE HIGH WILL SLOWLY MOVE TO THE EAST COAST THROUGH
SATURDAY NIGHT.
OUTLOOK...
MON...RAIN/LOW CIGS POSSIBLE...MAINLY NW.
TUE...RAIN/LOW CIGS POSSIBLE.
WED...RAIN AREAWIDE TRANSITIONS TO SHSN NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...TYBURSKI
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1255 PM EST FRI DEC 2 2011
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO PENNSYLVANIA TONIGHT AND CONTROL THE
LOCAL WEATHER UNTIL COLD FRONT MOVES IN FROM THE NORTHWEST EARLY
NEXT WEEK. THE COLD FRONT WILL MOST LIKELY STALL OVER THE STATE
AND LEAD TO RAIN FOR THE FIRST HALF OF THE WEEK. COLDER TEMPERATURES
WITH SCATTERED SNOW SHOWERS WILL THEN ENSUE IN THE MID WEEK.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
MID DECK ROLLING ACROSS THE AREA CURRENTLY WILL SLIDE TO THE EAST
AND DISSIPATE SOME AS IT DOES SO. MOST LOCATIONS WILL STAY FAIR
ALL EVENING. NEAR TERM GUID PORTRAYS THE LOW CLOUDS OVER THE
NORTHWEST LASTING FOR ONLY A FEW HOURS THIS EVENING...WITH JUST A
FLURRY OR TWO IN THE NW. HRRR PAINTS SOME FLURRIES IN THE
SW/LAURELS...BUT WILL NOT MENTION AT THIS POINT. GUSTY WNW WINDS
IN THE MTS WILL DIE DOWN QUICKLY THIS EVENING AS THE HIGH PRESSURE
BUILDS IN FROM THE WEST.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH SATURDAY NIGHT/...
CLEAR AND CALM FOR THE OVERNIGHT WITH AXIS OF SFC HIGH PRESSURE
OVERHEAD BEFORE SUNRISE. SOME OF THE COLDEST TEMPERATURES SO FAR
THIS YEAR. STILL LOOKING AT MINS AROUND 20F NEAR THE NEW YORK
BORDER...BUT WOULD NOT BE SURPRISED TO SEE READINGS DROP INTO THE
MID TEENS IN SOME OF THE NORMALLY COLDER SHELTERED VALLEY SPOTS.
LLVL FLOW GOES S/SERLY DURING THE DAY SAT...AND TEMPS SHOULD
RISE BACK TO NEAR NORMALS AFTER THE COLD START. CLOUDS WILL BE
TOUGH TO FIND EARLY...BUT HIGH CLOUDS FROM WARM ADVECTION ALOFT
WILL SHOW UP AS THE DAY CONTINUES. JUST P/C FOR SAT NIGHT WITH
SFC HIGH STRETCHED OUT ALL ALONG THE EAST COAST. 8H TEMPS RISE TO
+6C TO +8C BY SUN AM. DESPITE THIS...DECOUPLING WILL ALLOW THE
MINS TO DIP TO THE M/U20S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MAINLY DRY CONDITIONS WILL PERSIST INTO SUNDAY.
AN INCREASING SOUTHERLY BREEZE ON SUNDAY WILL HELP TO BOOST THE NEAR
TO SLIGHTLY BELOW NORMAL MAX TEMPS SATURDAY...TO A GOOD 5-7F ABOVE
NORMAL FOR SUNDAY. MAX TEMP DEPARTURES FROM NORMAL WILL BE GREATEST
ACROSS THE WRN MTNS WHERE HIGHS IN THE U40S TO LOWER 50S WILL BE 10F
OF MORE ABOVE NORMAL.
PARTLY TO MOSTLY SUNNY SKIES WILL BE FOUND ACROSS THE ERN HALF OF
THE STATE FOR MUCH OF SUNDAY...WHILE CLOUDS THICKEN UP ACROSS THE
WEST THROUGHOUT THE DAY. THERE WILL BE A CHANCE FOR A FEW SHOWERS
ACROSS THE NW LATE.
AS THE UPPER FLOW BACKS...AND THE NRN AND SRN STREAM TROFS TO OUR
WEST PHASE/AMPLIFY...THE CFRONT WILL SLOW SIGNIFICANTLY ACROSS THE
REGION /AND MAY EVEN STALL OUT FOR A PERIOD MONDAY NIGHT THROUGH
TUESDAY/.
GFS AND EC BOTH INDICATE A PIECE OF THE SRN STREAM ENERGY HELPING TO
FORM A QUASI-CLOSED UPPER LOW ACROSS THE OHIO VALLEY...THEN OPENING
UP THE WAVE AS IT MOVES INTO THE NE U.S. DURING THE MIDWEEK.
THE TIMING OF THIS FEATURE IS MUCH SLOWER ON THE EC...AND ALSO
STRONGER...WHICH SUPPORTS A MORE WIDESPREAD AND MODERATELY HEAVY
RAIN EVENT...MIXING WITH OR CHANGING TO SNOW ACROSS THE WRN MTNS
WEDNESDAY THROUGH WED NIGHT. AGAIN THE GFS IS MORE PROGRESSIVE AND
WEAKER...LEADING TO PRECIP IN THE FORM OF SHOWERS OR A FEW PERIODS
OF STEADIER RAIN EXITING OUR ERN COUNTIES TUESDAY NIGHT.
GEFS PLUMES...WITH A LARGE SPREAD IN TIMING/AMOUNT AND TYPE OF
PRECIP...CAPTURE THIS HIGH UNCERTAINTY. THE CONFIDENCE THE EVENT
OCCURRING IN ONE FORM OR ANOTHER IS HIGH THOUGH.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
HIGH/MID CLOUD SHEET WILLDISSIPATE AS IT MOVES EAST THIS EVE...AND
THE LOW/MVFR ALMOST-IFR DECK IN THE NW WILL ALSO BREAK UP EARLY
TONIGHT. BY 03Z...IT SHOULD BE PRETTY MUCH CLEAR. THE CLEAR SKIES
WILL LAST INTO THE DAYTIME SAT...WITH ONLY HIGH CLOUDS FOR SAT
AFTN/NIGHT. GUSTY WINDS AT THIS TIME WILL DECREASE VERY RAPIDLY
THIS EVENING AS THE HIGH PRESSURE OFF TO THE WEST SETS UP
OVERHEAD. THE HIGH WILL SLOWLY MOVE TO THE EAST COAST THROUGH
SATURDAY NIGHT.
OUTLOOK...
MON...RAIN/LOW CIGS POSSIBLE...MAINLY NW.
TUE...RAIN/LOW CIGS POSSIBLE.
WED...RAIN AREAWIDE TRANSITIONS TO SHSN NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/CERU
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
933 PM CST SAT DEC 3 2011
.UPDATE...
PRE-FRONTAL TROUGH EXTENDS FROM WACO TO LAMPASAS TO JUNCTION TO
DRYDEN WHILE CANADIAN COLD FRONT EXTENDS FROM WICHITA FALLS TO
ABILENE TO MIDLAND. TROUGH AND FRONT HAVE SPEED UP SLIGHTLY AND
NEW 00Z NAM AND RUC BRING THESE FEATURES THROUGH SOUTH CENTRAL
TEXAS A LITTLE EARLIER THAN PREVIOUSLY FORECAST WHICH SEEMS
REASONABLE. MAIN IMPACTS ARE TO GO WITH COOLER TEMPERATURES AND
EARLIER WIND SHIFTS TO NORTHERLY ON SUNDAY...ESPECIALLY DURING THE
LATE MORNING AND AFTERNOON ALONG WITH LOWER POST-FRONTAL DEWPOINTS
FOR SUNDAY THROUGH MONDAY. REMAINDER OF YOUR SOUTH CENTRAL TEXAS
FORECAST IS ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 538 PM CST SAT DEC 3 2011/
AVIATION...
A BRIEF WINDOW OF VFR CONDITIONS WILL CONTINUE THROUGH THE NEXT
FEW HOURS BEFORE THE ONSET OF MVFR CIGS BY ABOUT 03Z. STREAMER
SHOWERS WILL CONTINUE TO DEVELOP MAINLY EAST OF A LINE FROM KERV
TO KHDO TO KCOT THROUGH THE EVENING HOURS AS WARM AIR ADVECTION
PERSISTS IN ADVANCE OF AN APPROACHING COLD FRONT. THE DEEP
MOISTURE IN THE LOWER LEVELS WILL PROMOTE THE DETERIORATION OF
CIGS TO IFR AND POTENTIALLY LIFR CONDITIONS OVERNIGHT. AHEAD OF THE
FRONT...A MIX OF -DZ/BR/-SHRA IS EXPECTED TO LOWER VSBYS TO MVFR/IFR
PARTICULARLY AT KAUS/KSAT/KSSF. THE COLD FRONT WILL ARRIVE SUNDAY
MORNING...BUT IMPROVEMENTS TO CIGS AND VSBYS WILL BE SLOW WITH VFR
CONDITIONS NOT EXPECTED TO RETURN DURING THE 24-HR NOR 30-HR TAF
PERIODS.
PREV DISCUSSION... /ISSUED 314 PM CST SAT DEC 3 2011/
DISCUSSION...
PRE-FRONTAL TROUGH/DRY LINE HAS PUSHED INTO THE FAR WESTERN CWA
THIS AFTERNOON WITH GOOD MIXING/CLEARING ACROSS THE WESTERN COUNTIES.
THE SKIES OVER THE EASTERN COUNTIES GENERALLY ALONG AND EAST OF
I35 HAVE REMAINED MOSTLY CLOUDY WITH PATCHY LIGHT RAIN AND DRIZZLE
CONTINUING IN THE DEEP SLY GULF FLOW. RAIN CHANCES WILL INCREASE
AGAIN LATER THIS EVENING INTO THE OVERNIGHT HOURS AND SUNDAY.
COMBINATION OF UPPER AIR DISTURBANCES IN THE SWLY FLOW
ALOFT...CONVERGENCE ALONG THE PRE-FRONTAL SURFACE TROF...AND THE
INCREASING LOW LEVEL GULF FLOW WILL RESULT IN GOOD CHANCES FOR
DEEP CONVECTION. BECAUSE OF THE DEEP GULF INFLOW AHEAD OF THE
TROUGH...WILL SEE GENEROUS QPF VALUES ESPECIALLY ACROSS THE NE/ERN
COUNTIES. RAINFALL AMOUNTS OF ONE HALF TO ONE INCH OVER THE NEXT
24 HOURS WITH ISOLATED STORM TOTALS OF NEAR 2 INCHES POSSIBLE.
THE COLD FRONT WAS PUSHING THROUGH THE TX PANHANDLE THIS AFTERNOON
AND MODELS HAVE SLOWED THE PROGRESSION THRU S TX ON DURING THE
DAY ON SUNDAY. CURRENT THINKING IS A FRONTAL PASSAGE INTO THE NRN
HILL COUNTRY/EDWARDS PLATEAU BY 6 AM AND TO NEAR I10/HIGHWAY 90 BY
AROUND NOON...AND THRU THE REMAINDER OF THE CWA BY 5 PM. HIGH
TEMPERATURES WILL OCCUR JUST AHEAD OF THE COLD FRONT AND
TEMPS ACROSS THE SRN CWA COULD REACH THE MID OR UPPER 70S. WILL
SEE SLOWLY FALLING TEMPERATURES BEHIND THE FRONT AS COLD AIR
ADVECTION WILL BEHIND TO INCREASE LATE SUNDAY NIGHT INTO MONDAY.
MONDAY WILL BE THE MORE BONE CHILLING DAY WITH THE COMBINATION OF
COLD...WIND AND POST FRONTAL OVERRUNNING LIGHT RAIN.
WINTER PRECIPITATION FOR THE FAR NRN COUNTIES APPEARS UNLIKELY GIVEN
THE WARMER 12Z SOUNDING TEMP PROFILE FOR MONDAY NIGHT/TUESDAY
MORNING...AND MOST PRECIPITATION WILL BE ENDING FROM THE WEST BY
SUNRISE TUESDAY MORNING. GRADUAL CLEARING TUESDAY WITH ALLOW FOR
A COUPLE OF NIGHTS OF FREEZING TEMPERATURES AREA WIDE TUESDAY
NIGHT AND WEDNESDAY NIGHT. STRONG WESTERLY FLOW ALOFT WILL RESULT
IN A QUICK RETURN OF MOISTURE AND OVERRUNNING SETTING UP FOR LATE
THURSDAY INTO FRIDAY AHEAD OF THE NEXT COLD FRONT. ANOTHER FAIRLY
GOOD SHOT OF COLD CANADIAN AIR WILL ARRIVE FRIDAY NIGHT INTO
SATURDAY...HOWEVER IT DOES NOT APPEAR THERE WILL BE ANY POST
FRONTAL PRECIPITATION AS A DRY WNWLY FLOW DEVELOP BEHIND A SHORT
WAVE AS THE COLD AIR ADVECTION BEGINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 54 58 44 49 36 / 80 80 90 60 20
AUSTIN BERGSTROM INTL AIRPORT 57 59 43 50 34 / 80 80 90 60 30
NEW BRAUNFELS MUNI AIRPORT 62 63 44 50 35 / 70 70 80 50 20
BURNET MUNI AIRPORT 47 49 40 47 35 / 80 80 90 50 20
DEL RIO INTL AIRPORT 55 56 45 52 36 / 50 30 50 20 10
GEORGETOWN MUNI AIRPORT 52 55 40 47 34 / 80 80 90 60 20
HONDO MUNI AIRPORT 63 63 45 53 35 / 70 50 80 30 20
SAN MARCOS MUNI AIRPORT 61 63 45 48 36 / 70 70 90 50 30
LA GRANGE - FAYETTE REGIONAL 64 67 48 50 38 / 70 80 90 70 30
SAN ANTONIO INTL AIRPORT 62 63 46 53 37 / 70 60 80 40 20
STINSON MUNI AIRPORT 64 64 47 52 38 / 70 60 80 40 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...25
SYNOPTIC/GRIDS...04
PUBLIC SERVICE/DATA COLLECTION...19
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
613 PM CST SAT DEC 3 2011
.UPDATE...
PRECIP CONTINUES TO EXPAND IN AREAL COVERAGE OVER THE NORTHEAST
QUADRANT OF THE CWA. LATEST RUC ANALYSIS SHOWS THE STRONG LIFT
RESPONSIBLE FOR THE PRECIP ON THE 295K ISENTROPIC SURFACE. 35
KNOT SOUTHERLY WINDS ARE QUICKLY LIFTING MOIST PARCELS FROM 975
MB TO 875 MB AS THE COLDER AIR MASS MOVES EAST. UPPED POPS IN THE
0-6Z TIMEFRAME TO 100 PERCENT FOR AREAS EAST AND NORTH OF A
SHERMAN TO DALLAS TO CANTON LINE GIVEN THE EXPECTED INTENSITY OF
THIS LIFT AND CURRENT RADAR TRENDS. THE RUC SHIFTS THE BEST LIFT
ASSOCIATED WITH THE COLD AIR WEDGE TO THE SOUTH LATER TONIGHT AND
WILL HAVE 80 POPS FOR THE SOUTHERN ZONES AFTER 6Z.
WIDESPREAD PRECIP IS EXPECTED TOMORROW BEHIND THE FRONTAL BOUNDARY
AS WARM/MOIST AIR IS LIFTED OVER THE COLD AIR. BUMPED UP POPS TO
100 PERCENT FOR MOST OF THE CWA EXCEPT FOR THE NORTHWESTERN ZONES
FOR THE SUNDAY PERIOD.
85/NH
&&
.AVIATION...
BAND OF RAIN WILL CONTINUE TO MOVE THROUGH THE DFW TRACON DURING
THE NEXT FEW HOURS...BUT WILL SLOWLY CLEAR FROM WEST TO EAST. HAVE
INCLUDED VCTS AT DAL DUE TO PROXIMITY TO STRONGER CELL...BUT ANY
STORMS WILL BE VERY ISOLATED. DRIER AIR IS MOVING IN FROM THE WEST
AND CIGS WILL START OFF AT MVFR BUT SHOULD IMPROVE TO VFR WHEN
RAIN ENDS. HAVE RAIN ENDING AT 1Z AT FTW/AFW...2Z DFW/GKY...3Z AT
DAL. VFR WITH NO RAIN SHOULD PREVAIL FROM LATE THIS EVENING...BUT
MORE RAIN DEVELOP LATE TONIGHT AROUND 9Z FROM THE SOUTH. THIS RAIN
WILL BE FALLING FROM THE MID LEVELS AND THUS CONDITIONS MAY STAY
VFR UNTIL LOW LEVELS CAN SATURATE TOWARD SUNRISE. EXPECT RAIN/BR
TO CONTRIBUTE TO MVFR VSBY...WITH CIGS LIKELY FALLING TO IFR BY
LATE MORNING. RAIN SHOULD PREVAIL THROUGH THE DAY TOMORROW AND
THINK CIGS STAY IFR IN DAMP/CHILLY AIR MASS.
FOR WACO...BAND OF RAIN SHOULD MOVE IN AROUND 2-3Z AND DO NOT
EXPECT THE PUSH OF DRY AIR TO MAKE IT IN THERE THIS EVENING BEFORE
NEXT BATCH OF RAIN DEVELOPS FROM THE SOUTH. WILL PREVAIL RAIN WITH
MVFR CIGS THIS EVENING...WITH CIGS FALLING TO IFR DURING THE
OVERNIGHT AND STAYING THERE INTO TOMORROW AS WELL.
WINTER PRECIP POTENTIAL STILL LOOKS LOW IN DFW AREA...WITH SURFACE
TEMPERATURES LIKELY REMAINING ABOVE FREEZING WHEN PRECIP IS
FALLING. MODELS ARE UNANIMOUS ON FORECASTING TEMPS ABOVE FREEZING
AND AM NOT IMPRESSED WITH AMOUNT OF COLD AIR AVAILABLE ACROSS THE
NORTHERN AND CANADIAN PLAINS. DYNAMIC COOLING ALOFT MAY BRING
RAIN/SNOW LINE INTO CWA...BUT THIS STILL LOOKS LIKE IT WILL STAY
NW OF METROPLEX TAF SITES.
TR.92
&&
.PREV DISCUSSION... /ISSUED 321 PM CST SAT DEC 3 2011/
SHORTWAVE DISTURBANCE CONTINUES TO LIFT UP THROUGH THE SOUTHERN
PLAINS THIS AFTERNOON RESULTING IN THE SLOW EASTWARD PROGRESSION OF
A BAND OF LIGHT TO MODERATE RAIN CURRENTLY ALONG A LINE FROM
COMANCHE TO WEATHERFORD TO GAINESVILLE. LOW RAINFALL AMOUNTS FOR
MOST AREAS...BUT SOME ISOLATED AMOUNTS TO BETWEEN A QUARTER AND HALF
INCH WILL BE POSSIBLE AS THIS BAND MOVES ACROSS NORTH TEXAS. THE
RAIN-COOLED AIR HAS RESULTED IN THE OLD FRONT SAGGING TO A
GAINESVILLE TO DECATUR TO CISCO LINE THIS AFTERNOON WITH
TEMPERATURES IN THE 50S BEHIND THE FRONT WHILE REMAINING IN THE 60S
TO LOWER 70S AHEAD OF IT. A FEW EMBEDDED THUNDERSTORMS ARE
POSSIBLE...BUT NOT LIKELY THROUGH THIS EVENING.
A STRONGER COLD FRONT CAN BE SEEN NOW MOVING THROUGH THE HIGH PLAINS
OF EASTERN CO/WESTERN KS THIS AFTERNOON. THE FRONT SHOULD ARRIVE
INTO OUR FAR NORTHWEST COUNTIES BY MIDNIGHT...THEN QUICKLY PUSH TO
AN ATHENS...WACO...LAMPASAS LINE BY SUNRISE SUNDAY. THE FRONT WILL
CLEAR THE REMAINDER OF NORTH TEXAS BY LATE MORNING SUNDAY. THE
STRONG COLD FRONT WILL OVERTAKE OUR CURRENT FRONT WITH THE BULK OF
MODERATE RAIN AND ISOLATED THUNDERSTORMS OCCURRING AHEAD OF THE
FRONT. SOME LIGHT RAIN WILL LIKELY REMAIN BEHIND THE FRONT. HIGHS
SUNDAY WILL OCCUR BETWEEN MIDNIGHT AND MIDDAY SUNDAY...WITH FALLING
AFTERNOON TEMPERATURES AND GUSTY NORTH WINDS 15 TO 20 MPH AFTER
FROPA. THE GUSTY WINDS AND LIGHT RAIN WILL MAKE FOR A RAW AND WET
DAY ACROSS NORTH TEXAS...THOUGH OVERALL HEAVIER RAINFALL SHOULD
SHIFT TO THE SOUTH AND EAST OF OUR AREA LATE SUNDAY AFTERNOON AND
EVENING.
A MORE ROBUST SHORTWAVE DISTURBANCE ARRIVES LATE SUNDAY NIGHT INTO
MONDAY AND WILL INDUCE ISENTROPIC ASCENT ONCE AGAIN WITH A COLD AND
AT TIMES MODERATE RAIN ACROSS NORTH TEXAS. TEMPERATURES WILL LIKELY
FALL INTO THE MID 30S BY DAYBREAK MONDAY MORNING ACROSS AREAS TO THE
NORTHWEST OF THE DFW METROPLEX. MOST MODELS...INCLUDING SREF AND WRF
...ARE HOLDING THE DEEPER COLD AIR OFF TO THE NORTHWEST OF THIS AREA
THROUGH MIDDAY MONDAY. DESPITE TEMPERATURES JUST ABOVE FREEZING...A
RAIN/SNOW MIX COULD OCCUR ACROSS THIS AREA MONDAY MORNING AS THERMAL
PROFILES COOL QUICKLY TO OR JUST BELOW FREEZING. COLD RAIN IS
EXPECTED ELSEWHERE.
REGARDING THE WINTER WEATHER POTENTIAL...AS THE SHORTWAVE MOVES
QUICKLY ACROSS THE AREA...DRYING ABOVE THE BOUNDARY LAYER WILL
FOLLOW IN ITS WAKE. AS A RESULT OF THIS DRYING...ICE CRYSTAL
PRODUCTION WILL BE LIMITED AND A MIXTURE OF VERY LIGHT RAIN/
DRIZZLE/FLURRIES IS LIKELY. ISENTROPIC DOWNSLOPE CONTINUES DURING
THE OVERNIGHT HOURS INTO TUESDAY MORNING WITH CLOUDS GRADUALLY
DECREASING.
NORTH TEXAS WILL REMAIN UNDER THE INFLUENCE OF CYCLONIC FLOW ALOFT
THROUGH THE WEEK...RESULTING IN PARTLY CLOUDY SKIES AND COLD
CONDITIONS. THE STUBBORN UPPER LOW FINALLY OPENS UP AND LIFTS OUT
TUES NIGHT AND EARLY WEDNESDAY WITH SOME LIFT RETURNING TO THE NORTH
TEXAS. AT THIS TIME...WE FEEL MOISTURE WILL BE TOO LIMITED FOR
PRECIPITATION BUT WILL MONITOR CLOSELY. WE CONTINUE TO UNDERCUT MOS
HIGH TEMPERATURES SINCE THE COLD AIRMASS IS 5-7 KFT DEEP WITH ONLY A
SLOW MODIFICATION BY THURSDAY.
NEXT COLD FRONT IS EXPECTED TO ARRIVE FRIDAY...AS ANOTHER SHORTWAVE
DISTURBANCE MOVES SOUTHEAST ACROSS THE FRONT RANGE OF THE ROCKIES.
GFS IS THE FASTEST WITH THE COLD FRONT...WHILE THE SREF/CANADIAN/AND
ARE ECMWF SLOWER. FOR NOW...WILL LEAN TOWARD A SLOW CONSENSUS ON THE
FRONT WITH WARMER TEMPERATURES FRIDAY THAN WHAT THE MAV MOS
GUIDANCE. WE WILL ALSO LEAVE THIS PERIOD DRY WITH UNCERTAINTIES ON
MOISTURE AVAILABILITY AND TIMING OF BOTH SURFACE AND UPPER LEVEL
FEATURES.
05/42
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 41 45 38 40 29 / 80 100 90 60 20
WACO, TX 48 49 39 44 30 / 70 100 90 60 20
PARIS, TX 49 50 38 44 29 / 100 100 80 70 20
DENTON, TX 38 42 37 38 27 / 70 100 80 60 20
MCKINNEY, TX 42 45 37 41 29 / 100 100 80 60 20
DALLAS, TX 43 47 38 41 30 / 90 100 90 60 20
TERRELL, TX 49 49 39 44 30 / 100 100 90 70 20
CORSICANA, TX 52 52 40 45 31 / 70 100 90 70 20
TEMPLE, TX 54 54 40 46 30 / 80 100 90 60 20
MINERAL WELLS, TX 37 41 34 36 26 / 40 90 70 60 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
85/85
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
545 AM CST FRI DEC 2 2011
.UPDATE...
SEE AVIATION DISCUSSION BELOW.
&&
.AVIATION...
AVIATION CONDITIONS WILL REMAIN PROBLEMATIC THROUGH THE PERIOD
ACROSS WEST CENTRAL TEXAS TERMINALS. COLD FRONT HAS CLEARED ALL OF
THE SITES EARLY THIS MORNING...WITH MVFR CIGS AND PATCHY AREAS OF
LIGHT RAIN BEHIND THE FRONT. THESE CONDITIONS SHOULD PERSIST FOR
MUCH OF THE MORNING HOURS...AND PROBABLY WELL INTO THE AFTERNOON.
AS A STRONG LOW LEVEL JET BRINGS MOISTURE UP AND OVER THE BOUNDARY
LATE THIS AFTERNOON AND INTO TONIGHT...CONDITIONS SHOULD QUICKLY
DETERIORATE ACROSS ALL SITES...PERHAPS EVEN DOWN INTO THE LIFR
RANGE. HOW QUICKLY THIS HAPPENS...AND WHEN IT STARTS REMAINS A BIG
QUESTION THOUGH. WITH THIS MUCH WARM ADVECTION OVER THE
FRONT...THE FRONT WILL EVENTUALLY BEGIN TO LIFT BACK NORTH AS A
WARM FRONT. AGAIN...WHEN THIS STARTS TO OCCUR IS VERY
UNCERTAIN...BUT ANTICIPATING A RAPID NORTHWARD MOVEMENT OF THE
FRONT BACK TO NEAR THE INTERSTATE 20 CORRIDOR BY MORNING.
CONDITIONS NORTH OF THE FRONT WILL CONTINUE TO BE A CONCERN..BUT
CONDITIONS SOUTH OF THE FRONT MAY ACTUALLY IMPROVE BY SUNRISE
SATURDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 345 AM CST FRI DEC 2 2011/
SHORT TERM...
COMPLICATED FORECAST CONTINUES FOR WEST CENTRAL TEXAS. STRONG COLD
FRONT HAS CLEARED ALL BUT THE EXTREME SOUTHEAST PORTIONS OF THE AREA
AS OF 09Z...WITH ONLY JUNCTION AND MASON HAVING NOT SEEN THE FRONTAL
PASSAGE SO FAR. THE NAM AND THE RUC HAVE BOTH HANDLED THE MOVEMENT
OF THE FRONT IN THE SHORT TERM FAIRLY WELL...AND THEY BOTH PUSH THE
FRONT THROUGH THE REMAINDER OF THE AREA BY 12Z...AND THEN STALL IT
JUST TO THE SOUTH. PRESSURE RISES BEHIND THE FRONT HAVE SLOWLY
DECREASED...BUT THE GUSTY NORTH WINDS CONTINUE. GIVEN THESE
WINDS...AND THE DENSITY OF THE COLDER AIR MASS...WILL ASSUME THAT
THE MODELS ARE CORRECT IN PUSHING THE FRONT THROUGH THE REST OF THE
AREA BEFORE PULLING UP STATIONARY.
MEANWHILE...POTENT UPPER LEVEL STORM SYSTEM APPROACHING FROM THE
SOUTHWEST US WILL LEAD TO INCREASING WARM ADVECTION UP AND OVER THE
FRONTAL BOUNDARY...REACHING 40 KTS BY 00Z AND OVER 50 KTS BY
MIDNIGHT. DRIZZLE AND LIGHT RAIN HAS ALREADY BEEN DEVELOPING...AND
THIS WILL CONTINUE AS THIS ISENTROPIC LIFT STRENGTHENS. HAVE
INCREASED POPS FOR TODAY AND TONIGHT. THIS WARM AND MOIST AIR MASS
WILL RIDE UP AND OVER THE COLDER AIR AT THE SURFACE...LEAVING THE
BOUNDARY TO THE SOUTH. HOWEVER...AS THE WARM ADVECTION
INTENSIFIES...THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTHWARD THIS
EVENING...ALTHOUGH HOW FAR NORTH IS STILL A BIG QUESTION. IN ANY
CASE...DONT EXPECT TEMPERATURES TO DROP MUCH TONIGHT...AND ACROSS
MOST OF THE AREA..TEMPERATURES WILL ACTUALLY CLIMB SUBSTANTIALLY
OVERNIGHT.
07
LONG TERM...
A COLD AND UNSETTLED PATTERN WILL CONTINUE THROUGH MUCH OF THE
EXTENDED FORECAST. A MODEST WARM UP CAN BE EXPECTED ON SATURDAY AS
WARM FRONT LIFTS NORTH THROUGH WEST CENTRAL TEXAS. HIGH TEMPERATURES
WILL RANGE FROM NEAR 60 NORTH...TO NEAR 70 SOUTH. IN THE
MEANTIME...A LARGE UPPER LEVEL TROUGH WILL BE LOCATED ACROSS THE
DESERT SOUTHWEST...AND AN ARCTIC COLD FRONT WILL BE LOCATED OVER
THE SOUTHERN PLAINS. AN UPPER LEVEL SHORTWAVE TROUGH WILL TRACK
ACROSS THE NORTHERN PLAINS SATURDAY HELPING TO SEND THIS COLD
FRONT THROUGH WEST CENTRAL TEXAS SATURDAY NIGHT. SHOWERS WILL BE
POSSIBLE ALONG AND AHEAD OF THE BOUNDARY...AND THIS IS REFLECTED
IN THE CURRENT GRIDS. COLD AIR ADVECTION...CLOUD COVER AND LIGHT
RAIN WILL HELP TO KEEP TEMPERATURES DOWN ON SUNDAY. DROPPED HIGH
TEMPERATURES A FEW DEGREES...GENERALLY IN THE UPPER 30S TO MID
40S...AND THESE MAY NEED TO BE LOWERED ON FUTURE SHIFTS.
ON SUNDAY NIGHT...AFOREMENTIONED UPPER LEVEL TROUGH REMAINS ACROSS
THE DESERT SOUTHWEST...WHILE ANOTHER UPPER LEVEL SHORTWAVE TROUGH
SKIRTS ACROSS THE CENTRAL PLAINS. THIS WILL HELP TO SEND A
REINFORCING SHOT OF COLDER AIR INTO THE AREA...WITH NORTH WINDS
INCREASING MONDAY MORNING AND COLD AIR FILTERING IN. IN
ADDITION...UPPER LEVEL DISTURBANCES WILL CONTINUE TO MOVE ACROSS
THE AREA IN ADVANCE OF THE MAIN UPPER LEVEL TROUGH LOCATED OVER
THE SOUTHWEST STATES. THIS WILL LIKELY PRODUCE LIGHT PRECIPITATION
ACROSS THE AREA SUNDAY NIGHT AND MONDAY. THE MAIN QUESTION THEN
BECOMES...WHAT TYPE OF PRECIPITATION. MODEL SOUNDINGS AND
700MB/850MB TEMPERATURES ARE INDICATING A RAIN/SNOW MIX ACROSS THE
NORTHERN HALF OF THE AREA EARLY MONDAY...THEN TRANSITIONING TO
RAIN/SNOW ACROSS MUCH OF THE AREA BY LATE MONDAY...AND MOSTLY SNOW
ACROSS THE NORTHERN COUNTIES. THIS SCENARIO IS REFLECTED IN THE
CURRENT FORECAST PACKAGE. AT THIS TIME ANY ACCUMULATIONS SHOULD BE
LIGHT...BUT A LOT OF UNCERTAINTY REMAINS IN THE AMOUNT OF
PRECIPITATION AND THE PRECIPITATION TYPE SUNDAY AND MONDAY. HIGH
TEMPERATURES ON MONDAY WILL BE WELL BELOW NORMAL...RANGING FROM
THE MID 30S NORTH...TO NEAR 40 SOUTH. GIVEN THE FRIGID AIRMASS AND
EXPECTED CLOUD COVER...THE CURRENT HIGH TEMPERATURES IN THE
FORECAST MAY BE A BIT HIGH.
MODELS CONTINUE TO HANG THE UPPER LEVEL TROUGH WEST OF THE
AREA...BEFORE FINALLY SWINGING IT THROUGH LATE TUESDAY. INTRODUCED
SLIGHT CHANCE POPS ACROSS THE AREA MONDAY NIGHT...BEFORE CONDITIONS
IMPROVE TUESDAY MORNING. ANY PRECIPITATION THAT DOES OCCUR WILL
LIKELY FALL AS LIGHT SNOW. ANOTHER VERY COLD DAY IS LIKELY ON
TUESDAY...AND DROPPED TEMPERATURES A FEW DEGREES. A SLOW WARM UP
WILL ENSUE BY THE MIDDLE OF NEXT WEEK...WITH CLOSER TO NORMAL
TEMPERATURES RETURNING BY THURSDAY.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 38 38 63 32 39 / 60 60 60 20 30
SAN ANGELO 44 44 66 35 42 / 50 60 50 20 20
JUNCTION 55 55 69 40 44 / 40 60 40 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
345 AM CST FRI DEC 2 2011
.SHORT TERM...
COMPLICATED FORECAST CONTINUES FOR WEST CENTRAL TEXAS. STRONG COLD
FRONT HAS CLEARED ALL BUT THE EXTREME SOUTHEAST PORTIONS OF THE AREA
AS OF 09Z...WITH ONLY JUNCTION AND MASON HAVING NOT SEEN THE FRONTAL
PASSAGE SO FAR. THE NAM AND THE RUC HAVE BOTH HANDLED THE MOVEMENT
OF THE FRONT IN THE SHORT TERM FAIRLY WELL...AND THEY BOTH PUSH THE
FRONT THROUGH THE REMAINDER OF THE AREA BY 12Z...AND THEN STALL IT
JUST TO THE SOUTH. PRESSURE RISES BEHIND THE FRONT HAVE SLOWLY
DECREASED...BUT THE GUSTY NORTH WINDS CONTINUE. GIVEN THESE
WINDS...AND THE DENSITY OF THE COLDER AIR MASS...WILL ASSUME THAT
THE MODELS ARE CORRECT IN PUSHING THE FRONT THROUGH THE REST OF THE
AREA BEFORE PULLING UP STATIONARY.
MEANWHILE...POTENT UPPER LEVEL STORM SYSTEM APPROACHING FROM THE
SOUTHWEST US WILL LEAD TO INCREASING WARM ADVECTION UP AND OVER THE
FRONTAL BOUNDARY...REACHING 40 KTS BY 00Z AND OVER 50 KTS BY
MIDNIGHT. DRIZZLE AND LIGHT RAIN HAS ALREADY BEEN DEVELOPING...AND
THIS WILL CONTINUE AS THIS ISENTROPIC LIFT STRENGTHENS. HAVE
INCREASED POPS FOR TODAY AND TONIGHT. THIS WARM AND MOIST AIR MASS
WILL RIDE UP AND OVER THE COLDER AIR AT THE SURFACE...LEAVING THE
BOUNDARY TO THE SOUTH. HOWEVER...AS THE WARM ADVECTION
INTENSIFIES...THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTHWARD THIS
EVENING...ALTHOUGH HOW FAR NORTH IS STILL A BIG QUESTION. IN ANY
CASE...DONT EXPECT TEMPERATURES TO DROP MUCH TONIGHT...AND ACROSS
MOST OF THE AREA..TEMPERATURES WILL ACTUALLY CLIMB SUBSTANTIALLY
OVERNIGHT.
07
.LONG TERM...
A COLD AND UNSETTLED PATTERN WILL CONTINUE THROUGH MUCH OF THE
EXTENDED FORECAST. A MODEST WARM UP CAN BE EXPECTED ON SATURDAY AS
WARM FRONT LIFTS NORTH THROUGH WEST CENTRAL TEXAS. HIGH TEMPERATURES
WILL RANGE FROM NEAR 60 NORTH...TO NEAR 70 SOUTH. IN THE
MEANTIME...A LARGE UPPER LEVEL TROUGH WILL BE LOCATED ACROSS THE
DESERT SOUTHWEST...AND AN ARCTIC COLD FRONT WILL BE LOCATED OVER
THE SOUTHERN PLAINS. AN UPPER LEVEL SHORTWAVE TROUGH WILL TRACK
ACROSS THE NORTHERN PLAINS SATURDAY HELPING TO SEND THIS COLD
FRONT THROUGH WEST CENTRAL TEXAS SATURDAY NIGHT. SHOWERS WILL BE
POSSIBLE ALONG AND AHEAD OF THE BOUNDARY...AND THIS IS REFLECTED
IN THE CURRENT GRIDS. COLD AIR ADVECTION...CLOUD COVER AND LIGHT
RAIN WILL HELP TO KEEP TEMPERATURES DOWN ON SUNDAY. DROPPED HIGH
TEMPERATURES A FEW DEGREES...GENERALLY IN THE UPPER 30S TO MID
40S...AND THESE MAY NEED TO BE LOWERED ON FUTURE SHIFTS.
ON SUNDAY NIGHT...AFOREMENTIONED UPPER LEVEL TROUGH REMAINS ACROSS
THE DESERT SOUTHWEST...WHILE ANOTHER UPPER LEVEL SHORTWAVE TROUGH
SKIRTS ACROSS THE CENTRAL PLAINS. THIS WILL HELP TO SEND A
REINFORCING SHOT OF COLDER AIR INTO THE AREA...WITH NORTH WINDS
INCREASING MONDAY MORNING AND COLD AIR FILTERING IN. IN
ADDITION...UPPER LEVEL DISTURBANCES WILL CONTINUE TO MOVE ACROSS
THE AREA IN ADVANCE OF THE MAIN UPPER LEVEL TROUGH LOCATED OVER
THE SOUTHWEST STATES. THIS WILL LIKELY PRODUCE LIGHT PRECIPITATION
ACROSS THE AREA SUNDAY NIGHT AND MONDAY. THE MAIN QUESTION THEN
BECOMES...WHAT TYPE OF PRECIPITATION. MODEL SOUNDINGS AND
700MB/850MB TEMPERATURES ARE INDICATING A RAIN/SNOW MIX ACROSS THE
NORTHERN HALF OF THE AREA EARLY MONDAY...THEN TRANSITIONING TO
RAIN/SNOW ACROSS MUCH OF THE AREA BY LATE MONDAY...AND MOSTLY SNOW
ACROSS THE NORTHERN COUNTIES. THIS SCENARIO IS REFLECTED IN THE
CURRENT FORECAST PACKAGE. AT THIS TIME ANY ACCUMULATIONS SHOULD BE
LIGHT...BUT A LOT OF UNCERTAINTY REMAINS IN THE AMOUNT OF
PRECIPITATION AND THE PRECIPITATION TYPE SUNDAY AND MONDAY. HIGH
TEMPERATURES ON MONDAY WILL BE WELL BELOW NORMAL...RANGING FROM
THE MID 30S NORTH...TO NEAR 40 SOUTH. GIVEN THE FRIGID AIRMASS AND
EXPECTED CLOUD COVER...THE CURRENT HIGH TEMPERATURES IN THE
FORECAST MAY BE A BIT HIGH.
MODELS CONTINUE TO HANG THE UPPER LEVEL TROUGH WEST OF THE
AREA...BEFORE FINALLY SWINGING IT THROUGH LATE TUESDAY. INTRODUCED
SLIGHT CHANCE POPS ACROSS THE AREA MONDAY NIGHT...BEFORE CONDITIONS
IMPROVE TUESDAY MORNING. ANY PRECIPITATION THAT DOES OCCUR WILL
LIKELY FALL AS LIGHT SNOW. ANOTHER VERY COLD DAY IS LIKELY ON
TUESDAY...AND DROPPED TEMPERATURES A FEW DEGREES. A SLOW WARM UP
WILL ENSUE BY THE MIDDLE OF NEXT WEEK...WITH CLOSER TO NORMAL
TEMPERATURES RETURNING BY THURSDAY.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 38 38 63 32 39 / 60 60 60 20 30
SAN ANGELO 44 44 66 35 42 / 50 60 50 20 20
JUNCTION 55 55 69 40 44 / 40 60 40 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/DANIELS
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
813 PM CST SAT DEC 3 2011
.UPDATED...CONCERNING HEADLINES.
AVAILABLE REPORTS IN THE ADVISORY AREA SO FAR THIS EVENING RANGE
UP TO 2 INCHES. IR LOOP SHOWS BEST ENHANCEMENT HAS QUICKLY SHIFTED
NORTHEASTWARD INTO UPPER MICHIGAN. RADAR AND OBS ACROSS THE REGION
INDICATE THE RAIN SNOW LINE EXTENDS FROM NORTHWEST IOWA TO RST TO
STE TO JUST SOUTH OF IMT. A SURFACE LOW WAS OVER SOUTHERN IOWA
EARLY THIS EVENING AND WILL BE ENTERING SOUTHWEST WISCONSIN LATE
THIS EVENING AND NEARLY TRACKING ALONG THE RAIN SNOW LINE
OVERNIGHT. A LARGE AREA OF RAIN WAS IN THE WARM SECTOR OF THE LOW
OVER IOWA AND SOUTHERN WISCONSIN MOVING TOWARD EASTERN WISCONSIN.
PARTS OF EASTERN WISCONSIN MAY SEE UP TO AN ADDITIONAL INCH OF
RAIN OVERNIGHT.
BUT BACK TO THE ADVISORY...BEST SNOW GROWTH REGION WAS OVER
NORTHWEST WISCONSIN AND MAY INCLUDE WESTERN PORTIONS OF ONEIDA AND
VILAS COUNTIES. THIS SNOW GROWTH REGION IS PROGGED TO SAG INTO
NORTH CENTRAL WISCONSIN OVERNIGHT AS THE H8 LOW AND SURFACE LOW
TRACKS OVER. NOT OUT OF THE QUESTION A WARNING MAY BE NEEDED AS
THESE MORE FAVORABLE DYNAMICS PLAY A ROLE...BUT FOR NOW WILL
CONTINUE THE HIGH END ADVISORY.
TDH
&&
.PREV DISCUSSION...ISSUED AT 505 PM CST SAT DEC 3 2011...
SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DEVELOPING
LOW PRESSURE SYSTEM MOVING NORTHEAST OVER SOUTH-CENTRAL KANSAS JUST
AHEAD OF A SHORTWAVE TROUGH. ATTACHED TO THE SURFACE LOW TO THE
NORTHEAST RUNS A COLD FRONT OVER CENTRAL IOWA INTO NORTHWEST
WISCONSIN. FIRST BATCH OF PRECIP IS RIDING ALONG THE 850MB
BAROCLINIC ZONE OVER THE SOUTHEASTERN HALF OF WISCONSIN THOUGH SOME
BREAKS ARE SPREADING OVER EASTERN IOWA AND NORTHERN ILLINOIS...THAT
MAY SPELL A BREAK IN THE PRECIP FOR A BRIEF PERIOD LATE THIS
AFTERNOON OVER E-C WISCONSIN. THE MAIN AXIS OF PRECIP...HOWEVER...
EXISTS JUST TO THE EAST OF THE SURFACE LOW ON THE NOSE OF A 60 KT
LLJ AND UPPER DIVERGENT AREA WITHIN THE COUPLED JET. SOME HIGHER
REFLECTIVITIES ARE ALSO DEVELOPING OVER WESTERN WISCONSIN WITHIN A
STRENGTHENING FGEN ZONE...SO WILL JUST START THE WINTER HEADLINES
WITH THE AFTERNOON PACKAGE. AS THE LOW TRACKS NORTHEAST OVER THE
NEXT 24 HOURS...THE OBVIOUS CONCERNS ARE SNOW AMOUNTS AND
HEADLINES.
TONIGHT...FOLLOWED A SREF/GFS BLEND TONIGHT...WHICH SPLITS THE
DIFFERENCE BETWEEN THE STRONGER NAM AND WEAKER ECMWF WHILE KEEPING
THE CONSENSUS TRACK. LOW PRESSURE OVER THE CENTRAL PLAINS WILL
RAPIDLY MOVE NE TOWARDS THE MID-MISSISSIPPI VALLEY THIS
EVENING...AND NORTHERN LAKE MICHIGAN BY 12Z SUNDAY. AHEAD OF THE
LOW...A BEEFY LLJ WILL SHIFT INTO SOUTHERN WISCONSIN THIS
EVENING...THEREBY INCREASING CONVERGENCE ALONG THE STALLED
BAROCLINIC ZONE STRETCHING ACROSS THE STATE...AND 850-700MB FGEN IN
THE PROCESS. COMBINED WITH STRONG QG FORCING FROM SHORTWAVE ENERGY
AND A WIDE OPEN GULF (PWATS 150-200 PCT OF NORMAL)...THE BEEFY SLUG
OF PRECIP OVER THE PLAINS WILL HAVE NO TROUBLE SPREADING ACROSS THE
STATE THIS EVENING. PTYPE REMAINS PROBLEMATIC AS THE 12Z MODEL RUNS
HAVE TRENDED SLIGHTLY WARMER WITH THE THERMAL PROFILE AS THE LOW
PUSHES WARMER AIR ALOFT SLIGHTLY FARTHER NORTH THAN PREVIOUS RUNS.
THIS WILL PLACE THE RAIN-SNOW MIX AREA FROM WOOD COUNTY TO NORTHERN
OCONTO AND MARINETTE. NORTH OF THE RAIN-SNOW LINE SHOULD RESIDE THE
AXIS OF HEAVIEST SNOWFALL...WHICH LINES UP WITH THE EXTRAPOLATED
SOUTHERN EDGE OF THE COMMA HEAD FROM APPROX MERRILL TO CRANDON.
WITH SLIGHTLY COLDER AIR IN PLACE COMPARED TO THE FIRST SNOW STORM IN
NOVEMBER...SNOW RATIOS WILL RUN BETWEEN 10-14:1 OVER THIS AREA
ACCORDING TO THE COBB SNOWFALL ALGORITHM. WITH QPFS AROUND 0.4 TO
0.5 INCHES...THIS AMOUNTS TO A GOOD 4-6 INCH SWATH OF SNOW TONIGHT
(5 TO 7 INCHES OVERALL)...THOUGH THE BULK OF THE PRECIP WILL LIKELY FALL
THIS EVENING. THE FOX VALLEY AND LAKESHORE WILL RESIDE WITHIN THE
WARM SECTOR OF THE STORM...WHICH MEANS MOSTLY RAIN TONIGHT...THOUGH
SOME SNOW MAY MIX IN LATE. ENTERTAINED SOME THOUGHTS OF UPGRADING TO
A WARNING GIVEN THE HEAVY SNOW OBS UPSTREAM...BUT GIVEN THE
RELATIVELY LOW IMPACT OF THE SNOW (DURING THE NIGHT ON A
WEEKEND)...WILL STICK WITH ADVISORY HEADLINES. ALSO THOUGHT ABOUT
TRIMMING THE ADVISORY TO THE NW BY A ROW OF COUNTIES...BUT
COORDINATION WITH SURROUNDING OFFICES YIELDED A RELUCTANCE...DUE TO
THE SLOPPINESS OF THE MIX AND POTENTIAL FOR FREEZING DRIZZLE. AS A
RESULT...WILL KEEP CURRENT HEADLINES AS THEY CURRENTLY STAND BUT
STRESS THE HEAVY SNOWFALL RATES ARRIVING THIS EVENING.
SUNDAY...THE LOW PRESSURE WILL QUICKLY EXIT TO SOUTHEAST ONTARIO BY
18Z SUNDAY BUT WILL HAVE THE BACK EDGE OF THE COMMA HEAD SHIFTING NE
OVER N-C AND FAR NORTHEAST WISCONSIN. SOME MID-LEVEL FGEN WILL
LINGER WHICH WILL RESULT IN ANOTHER HALF INCH TO AN INCH OVER N-C
WISCONSIN EARLY IN THE MORNING. BUT OTHERWISE...SNOW WILL BE
TAPERING DOWN TO JUST FLURRIES IN THE MORNING...WHILE COLDER AIR
FILTERS ACROSS THE REGION. LOW LEVEL TROUGHINESS AND CYCLONIC FLOW
WILL HANG AROUND FOR MUCH OF THE DAY...SO NOT ANTICIPATING MUCH
CLEARING TOMORROW. HIGHS MAINLY IN THE LOW TO MIDDLE 30S.
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...THE MAIN FCST
CONCERNS WILL BE MINOR LAKE EFFECT SNOW POTENTIAL OVER NORTHERN
WI EARLY IN THE PERIOD...THEN THE POTENTIAL FOR SNOW AND MUCH
COLDER TEMPERATURES WITH AN ARCTIC FRONTAL PASSAGE LATE NEXT
WEEK.
A STRONG...HIGH AMPLITUDE RIDGE WILL COVER THE EASTERN PACIFIC...
WESTERN CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...
WITH A POSITIVELY-TILTED UPPER TROF EXTENDING FROM CENTRAL CANADA
INTO THE SOUTHWEST UNITED STATES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON TUESDAY...WITH LITTLE IMPACT ON OUR WEATHER. SHORT-WAVE
ENERGY WILL TOP THE WESTERN RIDGE EARLY NEXT WEEK...THEN EVENTUALLY
HELP TO CARVE A BROAD TROF OVER THE CENTRAL U.S. BY THU/FRI. A
SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN WI LATE IN THE WEEK...
WITH H8 TEMPS PLUMMETING TO AROUND -20 C. THIS WILL LEAD TO OUR
COLDEST TEMPERATURES SO FAR THIS SEASON.
A LARGE RIDGE OF HIGH PRESSURE WILL BE CENTERED OVER THE NORTHERN
ROCKIES AND NORTHERN PLAINS SUN NGT INTO MON...WITH COLD NORTH
FLOW RESULTING IN SCT LAKE-EFFECT SNOW SHOWERS OVER MAINLY NC WI.
THE SNOW SHOWERS MAY LINGER INTO MONDAY NIGHT...BUT SHOULD COME TO
AN END ON TUESDAY AS THE RIDGE AXIS PUSHES ACROSS WI.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING SOMETIME DURING
THE THU/FRI TIME FRAME. DURING THIS PERIOD...LLVL FLOW IS EXPECTED
TO BE TOO WESTERLY FOR LK-EFFECT. THE ECMWF AND A FEW OF THE GFS
ENSEMBLE MEMBERS SUGGEST THAT A SFC WAVE WILL DEVELOP ALONG THE
ARCTIC BOUNDARY LATE IN THE WEEK...AS THE RRQ OF A STRONG UPPER
LEVEL JET PULLS THROUGH THE REGION. IF THIS PLAYS OUT...WE COULD
BRING SEE SEVERAL INCHES OF POWDERY SNOW SOMETIME DURING THE
THURSDAY NIGHT TO SATURDAY PERIOD. FOR NOW...WILL FOLLOW THE
CONCENSUS OF AREA OFFICES...AND JUST MENTION SMALL POPS ACROSS OUR
SOUTHERN AND EASTERN COUNTIES ON THU NGT/FRI. THERE IS A HIGHER
DEGREE OF CONFIDENCE IN A TREND TOWARD MUCH COLDER TEMPERATURES
LATE IN THE WEEK...ALTHOUGH THE NEW ECMWF IS SLOWER WITH THE
TIMING OF THE ARCTIC BOUNDARY. SUBSEQUENT FCSTS SHOULD BE BETTER
ABLE TO PINPOINT THE FRONTAL TIMING AND SNOWFALL POTENTIAL LATE
NEXT WEEK.
&&
.AVIATION...RAIN SNOW LINE ROUGHLY FROM STE TO IMT LATE THIS
AFTERNOON WILL CHANGE LITTLE EARLY THIS EVENING AS THE SURFACE
AND H8 LOW TRACK NORTHEAST OVER THE STATE. SOME OBSERVATIONS AT
1/4 MILE OVER CENTRAL WISCONSIN BUT CAMERAS INDICATE FOG WITH SNOW
VS HEAVY SNOW. NEVERTHELESS LIFR CIGS ALONG WITH IFR VSBYS WITH
SCATTERED LIFR VSBYS WILL CONTINUE TONIGHT. BRUNT OF THE
ACCUMULATING SNOW TO IMPACT CENTRAL AND NORTH CENTRAL TONIGHT.
CIGS AND VSBYS TO IMPROVE TO MVFR LEVELS SUNDAY AS THE SYSTEM
DEPARTS TO THE NORTHEAST SUNDAY MORNING.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ005-010>013-
018-019-021-030-035.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
505 PM CST SAT DEC 3 2011
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DEVELOPING
LOW PRESSURE SYSTEM MOVING NORTHEAST OVER SOUTH-CENTRAL KANSAS JUST
AHEAD OF A SHORTWAVE TROUGH. ATTACHED TO THE SURFACE LOW TO THE
NORTHEAST RUNS A COLD FRONT OVER CENTRAL IOWA INTO NORTHWEST
WISCONSIN. FIRST BATCH OF PRECIP IS RIDING ALONG THE 850MB
BAROCLINIC ZONE OVER THE SOUTHEASTERN HALF OF WISCONSIN THOUGH SOME
BREAKS ARE SPREADING OVER EASTERN IOWA AND NORTHERN ILLINOIS...THAT
MAY SPELL A BREAK IN THE PRECIP FOR A BRIEF PERIOD LATE THIS
AFTERNOON OVER E-C WISCONSIN. THE MAIN AXIS OF PRECIP...HOWEVER...
EXISTS JUST TO THE EAST OF THE SURFACE LOW ON THE NOSE OF A 60 KT
LLJ AND UPPER DIVERGENT AREA WITHIN THE COUPLED JET. SOME HIGHER
REFLECTIVITIES ARE ALSO DEVELOPING OVER WESTERN WISCONSIN WITHIN A
STRENGTHENING FGEN ZONE...SO WILL JUST START THE WINTER HEADLINES
WITH THE AFTERNOON PACKAGE. AS THE LOW TRACKS NORTHEAST OVER THE
NEXT 24 HOURS...THE OBVIOUS CONCERNS ARE SNOW AMOUNTS AND
HEADLINES.
TONIGHT...FOLLOWED A SREF/GFS BLEND TONIGHT...WHICH SPLITS THE
DIFFERENCE BETWEEN THE STRONGER NAM AND WEAKER ECMWF WHILE KEEPING
THE CONSENSUS TRACK. LOW PRESSURE OVER THE CENTRAL PLAINS WILL
RAPIDLY MOVE NE TOWARDS THE MID-MISSISSIPPI VALLEY THIS
EVENING...AND NORTHERN LAKE MICHIGAN BY 12Z SUNDAY. AHEAD OF THE
LOW...A BEEFY LLJ WILL SHIFT INTO SOUTHERN WISCONSIN THIS
EVENING...THEREBY INCREASING CONVERGENCE ALONG THE STALLED
BAROCLINIC ZONE STRETCHING ACROSS THE STATE...AND 850-700MB FGEN IN
THE PROCESS. COMBINED WITH STRONG QG FORCING FROM SHORTWAVE ENERGY
AND A WIDE OPEN GULF (PWATS 150-200 PCT OF NORMAL)...THE BEEFY SLUG
OF PRECIP OVER THE PLAINS WILL HAVE NO TROUBLE SPREADING ACROSS THE
STATE THIS EVENING. PTYPE REMAINS PROBLEMATIC AS THE 12Z MODEL RUNS
HAVE TRENDED SLIGHTLY WARMER WITH THE THERMAL PROFILE AS THE LOW
PUSHES WARMER AIR ALOFT SLIGHTLY FARTHER NORTH THAN PREVIOUS RUNS.
THIS WILL PLACE THE RAIN-SNOW MIX AREA FROM WOOD COUNTY TO NORTHERN
OCONTO AND MARINETTE. NORTH OF THE RAIN-SNOW LINE SHOULD RESIDE THE
AXIS OF HEAVIEST SNOWFALL...WHICH LINES UP WITH THE EXTRAPOLATED
SOUTHERN EDGE OF THE COMMA HEAD FROM APPROX MERRILL TO CRANDON.
WITH SLIGHTLY COLDER AIR IN PLACE COMPARED TO THE FIRST SNOW STORM IN
NOVEMBER...SNOW RATIOS WILL RUN BETWEEN 10-14:1 OVER THIS AREA
ACCORDING TO THE COBB SNOWFALL ALGORITHM. WITH QPFS AROUND 0.4 TO
0.5 INCHES...THIS AMOUNTS TO A GOOD 4-6 INCH SWATH OF SNOW TONIGHT
(5 TO 7 INCHES OVERALL)...THOUGH THE BULK OF THE PRECIP WILL LIKELY FALL
THIS EVENING. THE FOX VALLEY AND LAKESHORE WILL RESIDE WITHIN THE
WARM SECTOR OF THE STORM...WHICH MEANS MOSTLY RAIN TONIGHT...THOUGH
SOME SNOW MAY MIX IN LATE. ENTERTAINED SOME THOUGHTS OF UPGRADING TO
A WARNING GIVEN THE HEAVY SNOW OBS UPSTREAM...BUT GIVEN THE
RELATIVELY LOW IMPACT OF THE SNOW (DURING THE NIGHT ON A
WEEKEND)...WILL STICK WITH ADVISORY HEADLINES. ALSO THOUGHT ABOUT
TRIMMING THE ADVISORY TO THE NW BY A ROW OF COUNTIES...BUT
COORDINATION WITH SURROUNDING OFFICES YIELDED A RELUCTANCE...DUE TO
THE SLOPPINESS OF THE MIX AND POTENTIAL FOR FREEZING DRIZZLE. AS A
RESULT...WILL KEEP CURRENT HEADLINES AS THEY CURRENTLY STAND BUT
STRESS THE HEAVY SNOWFALL RATES ARRIVING THIS EVENING.
SUNDAY...THE LOW PRESSURE WILL QUICKLY EXIT TO SOUTHEAST ONTARIO BY
18Z SUNDAY BUT WILL HAVE THE BACK EDGE OF THE COMMA HEAD SHIFTING NE
OVER N-C AND FAR NORTHEAST WISCONSIN. SOME MID-LEVEL FGEN WILL
LINGER WHICH WILL RESULT IN ANOTHER HALF INCH TO AN INCH OVER N-C
WISCONSIN EARLY IN THE MORNING. BUT OTHERWISE...SNOW WILL BE
TAPERING DOWN TO JUST FLURRIES IN THE MORNING...WHILE COLDER AIR
FILTERS ACROSS THE REGION. LOW LEVEL TROUGHINESS AND CYCLONIC FLOW
WILL HANG AROUND FOR MUCH OF THE DAY...SO NOT ANTICIPATING MUCH
CLEARING TOMORROW. HIGHS MAINLY IN THE LOW TO MIDDLE 30S.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...THE MAIN FCST
CONCERNS WILL BE MINOR LAKE EFFECT SNOW POTENTIAL OVER NORTHERN
WI EARLY IN THE PERIOD...THEN THE POTENTIAL FOR SNOW AND MUCH
COLDER TEMPERATURES WITH AN ARCTIC FRONTAL PASSAGE LATE NEXT
WEEK.
A STRONG...HIGH AMPLITUDE RIDGE WILL COVER THE EASTERN PACIFIC...
WESTERN CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...
WITH A POSITIVELY-TILTED UPPER TROF EXTENDING FROM CENTRAL CANADA
INTO THE SOUTHWEST UNITED STATES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON TUESDAY...WITH LITTLE IMPACT ON OUR WEATHER. SHORT-WAVE
ENERGY WILL TOP THE WESTERN RIDGE EARLY NEXT WEEK...THEN EVENTUALLY
HELP TO CARVE A BROAD TROF OVER THE CENTRAL U.S. BY THU/FRI. A
SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN WI LATE IN THE WEEK...
WITH H8 TEMPS PLUMMETING TO AROUND -20 C. THIS WILL LEAD TO OUR
COLDEST TEMPERATURES SO FAR THIS SEASON.
A LARGE RIDGE OF HIGH PRESSURE WILL BE CENTERED OVER THE NORTHERN
ROCKIES AND NORTHERN PLAINS SUN NGT INTO MON...WITH COLD NORTH
FLOW RESULTING IN SCT LAKE-EFFECT SNOW SHOWERS OVER MAINLY NC WI.
THE SNOW SHOWERS MAY LINGER INTO MONDAY NIGHT...BUT SHOULD COME TO
AN END ON TUESDAY AS THE RIDGE AXIS PUSHES ACROSS WI.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING SOMETIME DURING
THE THU/FRI TIME FRAME. DURING THIS PERIOD...LLVL FLOW IS EXPECTED
TO BE TOO WESTERLY FOR LK-EFFECT. THE ECMWF AND A FEW OF THE GFS
ENSEMBLE MEMBERS SUGGEST THAT A SFC WAVE WILL DEVELOP ALONG THE
ARCTIC BOUNDARY LATE IN THE WEEK...AS THE RRQ OF A STRONG UPPER
LEVEL JET PULLS THROUGH THE REGION. IF THIS PLAYS OUT...WE COULD
BRING SEE SEVERAL INCHES OF POWDERY SNOW SOMETIME DURING THE
THURSDAY NIGHT TO SATURDAY PERIOD. FOR NOW...WILL FOLLOW THE
CONCENSUS OF AREA OFFICES...AND JUST MENTION SMALL POPS ACROSS OUR
SOUTHERN AND EASTERN COUNTIES ON THU NGT/FRI. THERE IS A HIGHER
DEGREE OF CONFIDENCE IN A TREND TOWARD MUCH COLDER TEMPERATURES
LATE IN THE WEEK...ALTHOUGH THE NEW ECMWF IS SLOWER WITH THE
TIMING OF THE ARCTIC BOUNDARY. SUBSEQUENT FCSTS SHOULD BE BETTER
ABLE TO PINPOINT THE FRONTAL TIMING AND SNOWFALL POTENTIAL LATE
NEXT WEEK.
&&
.AVIATION...RAIN SNOW LINE ROUGHLY FROM STE TO IMT LATE THIS
AFTERNOON WILL CHANGE LITTLE EARLY THIS EVENING AS THE SURFACE
AND H8 LOW TRACK NORTHEAST OVER THE STATE. SOME OBSERVATIONS AT
1/4 MILE OVER CENTRAL WISCONSIN BUT CAMERAS INDICATE FOG WITH SNOW
VS HEAVY SNOW. NEVERTHELESS LIFR CIGS ALONG WITH IFR VSBYS WITH
SCATTERED LIFR VSBYS WILL CONTINUE TONIGHT. BRUNT OF THE
ACCUMULATING SNOW TO IMPACT CENTRAL AND NORTH CENTRAL TONIGHT.
CIGS AND VSBYS TO IMPROVE TO MVFR LEVELS SUNDAY AS THE SYSTEM
DEPARTS TO THE NORTHEAST SUNDAY MORNING.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ005-010>013-
018-019-021-030-035.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
329 PM CST FRI DEC 2 2011
.SHORT TERM...
TONIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
SHORTWAVE ENERGY EJECTING OUT OF A TROUGH IN THE SOUTHWEST U.S. WILL
BRING A PLUME OF MOISTURE INTO WISCONSIN TONIGHT THROUGH SUNDAY
MORNING. THIS PLUME IS APPARENT IN THE LATEST WATER VAPOR IMAGERY.
THIS TROUGH/SHORTWAVE WILL PHASE WITH A NORTHERN STREAM TROUGH OVER
THE WEEKEND...CREATING A PROLONGED PRECIP EVENT ACROSS WISCONSIN.
MODELS ARE IN FAIR AGREEMENT ABOUT WAITING UNTIL AFTER MIDNIGHT FOR
THE WALL OF WATER...OR DEEP MOISTURE...TO REACH SOUTH CENTRAL WI.
WHILE THERE MAY BE SOME PRECIP IN THE FORECAST AREA BEFORE 3
AM...THE MAIN SURGE WILL HIT MOST OF THE AREA BETWEEN 3 AND 6 AM.
THE PRECIP MAY HOLD OFF IN KENOSHA AND MILWAUKEE UNTIL RIGHT AROUND
6 AM/12Z. UPPER LEVEL DIVERGENCE INCREASES TONIGHT ALONG WITH
MODERATE 700MB UPWARD MOTION. ISENTROPIC LIFT SEEN ON THE 290K
ISENTROPIC LEVEL WITH CONDENSATION PRESSURE DEFICITS BELOW 5 MB ON
THE NAM BY SUNRISE SATURDAY.
PRECIP WILL MAINLY BE IN THE FORM OF RAIN IN THE ENTIRE FORECAST
AREA. THE ONLY EXCEPTION WILL BE AROUND THE DELLS AND GREEN
LAKE/MARQUETTE COUNTIES WHERE THE EVENT COULD BEGIN AS SNOW AND
SWITCH TO RAIN. WITH THE STRONG WARM AIR ADVECTION...SFC TEMPS ARE
EXPECTED TO WARM TO JUST ABOVE FREEZING WITH THE ONSET OF
PRECIPITATION...THUS LIMITING THE FREEZING RAIN OR SNOW POTENTIAL.
THE CENTER OF THE SURFACE LOW PRESSURE WILL TRACK RIGHT ACROSS SOUTH
CENTRAL WI LATE SAT AFTERNOON INTO SUNDAY MORNING...SO A LULL IN THE
PRECIPITATION IS EXPECTED IN SOUTHEAST WI...EAST OF MADISON. THE
LULL SHOULD BE FROM AROUND 2 PM SAT THROUGH SAT EVENING IN
MILWAUKEE. CLOUD COVER DURING THIS TIME IS UNCERTAIN...AS MODELS
SUGGEST CLEARING AND EXPERIENCE SUGGESTS STRATUS CLOUDS AND POSSIBLY
LIGHT FOG.
SATURDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
THE SHORTWAVE TROUGH LIFTING NEWD THROUGH THE GREAT PLAINS WILL
REACH NRN WI BY 12Z SUN AND WILL AID IN MINOR DEEPENING OF THE SFC
LOW AS IT TRACKS FROM ERN KS TO SE WI. A DRY SLOT WILL INITIALLY
BE OVER ERN WI SAT EVENING BUT WILL SHIFT EWD WITH A 60 KT LOW
LEVEL JET STREAM TO BRING A NEW SURGE OF WARM AND MOIST ADVECTION
AND SFC-850 MB FRONTOGENESIS. PWS TO INCREASE TO 0.80-0.90 INCHES WITH
WIDESPREAD MDT RAIN EXPECTED. THE CONSENSUS OF THE THERMAL FIELDS
WILL BRING A MIXTURE OF LGT RAIN AND LGT SNOW TO THE FAR WRN CWA
BETWEEN 09-12Z. PCPN TO QUICKLY DIMINISH SUN AM AS THE LOW LEVEL
JET STREAM SHIFTS INTO LOWER MI. LIKELY POPS EXPECTED EARLY IN
THE DAY FOR THE NE CWA WITH CHANCES ELSEWHERE. LGT RAIN WILL
CHANGE TO OR MIX WITH LGT SNOW BUT SNOW ACCUMULATIONS WILL LIKELY
REMAIN UNDER ONE HALF INCH IN THE NRN AND WRN CWA WITH TRACE
AMOUNTS AT BEST IN SE WI.
COLD AND DRY ADVECTION AND SUBSIDENCE SHOULD BE ENOUGH FOR CLOUD
COVER TO BECOME FEW-SCATTERED FOR SUN NT INTO MONDAY. A WEAKENING
LOW PRESSURE AREA AND SHORTWAVE TROUGH WILL THEN MOVE FROM THE NRN
PLAINS INTO THE GREAT LAKES FOR MONDAY. THE ONLY RESULT WILL BE A
DRY COLD FRONT WITH THE UPSTREAM POLAR HIGH OVER THE NRN AND
CENTRAL GREAT PLAINS.
.LONG TERM...
TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM
A HIGH PRESSURE RIDGE ASSOCIATED WITH THE POLAR HIGH OVER THE
CENTRAL PLAINS WILL MOVE ACROSS WI FOR TUE/TUE NT WHILE A LONG
WAVE UPPER TROUGH AND SFC TROUGH BRINGS PCPN TO SRN AND ERN UNITED
STATES. FOR THE REMAINDER OF THE WEEK A STRONG AND VERY LARGE
CYCLONE WILL MOVE ACROSS NRN CANADA AND OCCLUDE OVER AND NORTH OF
THE HUDSON BAY AREA LATER IN THE WEEK. THE NRN USA WILL BE ON THE
SRN FRINGES OF THIS CYCLONE WITH DRY WNWLY WINDS AND GRADUAL COLD
ADVECTION. DURING THIS TIME A 1040 MB ARCTIC HIGH WILL SLIDE SWD
ALONG THE LEE OF THE CANADIAN ROCKIES AND EVENTUALLY INTO THE MID
MO RIVER VALLEY ON FRI. SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED
LATER NEXT WEEK WITH THE LACK OF SNOW COVER INHIBITING GREATER
COOLING.
&&
.AVIATION/00Z TAFS/...
CLEAR SKIES THROUGH THE EVENING UNDER THE HIGH PRESSURE. HOWEVER
SOUTH WINDS DEVELOPING AHEAD OF LOW PRESSURE FROM WESTERN OKLAHOMA
TO MINNESOTA WILL BRING INCREASING/THICKENING AND LOWERING HIGH/MID
LEVEL CLOUDS THIS EVENING...FOLLOWED BY MVFR/IFR CIGS AND VSBYS...
ESPECIALLY IN SOUTH CENTRAL WISCONSIN DURING THE EARLY MORNING HOURS
SATURDAY. SOME FREEZING RAIN POTENTIAL MAINLY NORTH AND WEST OF
MADISON TO NEAR FOND DU LAC.
THERE WILL BE A LULL IN THE PRECIP SAT AFTERNOON. NOT SURE IF
CEILINGS WILL TANK WITHIN THE LULL AS THE SFC LOW MOVES OVERHEAD
DURING THIS TIME. LOW CIGS EXPECTED EARLY SAT EVENING...WHICH SHOULD
COME UP A BIT WHEN THE NEXT ROUND OF PRECIP HITS. PRECIP TYPE SHOULD
BE ALL RAIN FROM TONIGHT THROUGH SATURDAY NIGHT AT ALL TAF SITES.
LOW LEVEL WIND SHEAR EXPECTED TONIGHT INTO SATURDAY MORNING AS LOW
LEVEL JET MOVES OVERHEAD. NAM IS STRONGER WITH THE WINDS THAN THE
GFS...AND RUC IS IN BETWEEN. LLWS WILL BE POSSIBLE ONCE AGAIN SAT
NIGHT AS A NEW SURGE OF WARM AIR ADVECTION MOVES INTO SOUTHEAST WI.
&&
.MARINE...
SOUTH WINDS WILL INCREASE TONIGHT AND WINDS AND WAVES ARE EXPECTED
TO REACH LOWER-END SMALL CRAFT ADVISORY CONDITIONS LATE TONIGHT INTO
SATURDAY. WINDS AND WAVES WILL BE HIGH THROUGH SATURDAY
MORNING...THEN THERE WILL BE A LULL IN THE WINDS SATURDAY AFTERNOON
AS THE SURFACE LOW CROSSES SOUTHEAST WISCONSIN. WEST WINDS WILL
INCREASE BEHIND THE LOW ONCE AGAIN SAT NIGHT THROUGH AT LEAST MIDDAY
SUNDAY. A SMALL CRAFT ADVISORY IS IN EFFECT FROM 06Z TONIGHT THROUGH
18Z SUNDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY
FOR LMZ643>646.
&&
$$
TONIGHT/SATURDAY AND AVIATION/MARINE...MRC
SATURDAY NIGHT THROUGH FRIDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1131 AM CST FRI DEC 2 2011
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
347 AM CST FRI DEC 2 2011
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR AFTER MIDNIGHT TONIGHT
THROUGH SUNDAY MORNING AND POSSIBLE HAZARDS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH OVER SOUTHWEST CANADA...RIDGING OUT
AHEAD OVER THE NORTHERN PLAINS INTO MANITOBA...AND TROUGHING OVER
THE LAKE MICHIGAN AREA. ALSO OF NOTE IS IN THE SOUTHERN STREAM OF AN
UPPER LOW OVER THE DESERT SOUTHWEST. THE FORECAST AREA LIES IN
SUBSIDENCE IMMEDIATELY BEHIND THE LAKE MICHIGAN TROUGH...PROMOTING
HIGH PRESSURE AT THE SURFACE. IN FACT...THE SUBSIDENCE AND DRYING
HAS BEEN ENOUGH TO RESULT IN CLEAR SKIES OVER THE AREA. UPSTREAM 00Z
SOUNDINGS FROM INL AND ABR REFLECT THE DRYING WELL WITH PRECIPITABLE
WATER VALUES UNDER TWO TENTHS OF AN INCH. THE COMBINATION OF THE
CLEAR SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES TO DROP INTO
THE TEENS TO MID 20S. TO THE NORTHWEST...A STREAM OF UPPER LEVEL
MOISTURE CAN BE SEEN ACROSS THE NORTHERN PLAINS INTO SOUTH CENTRAL
CANADA ON WATER VAPOR....AHEAD OF THE UPPER TROUGH THERE...WHICH IS
MANIFESTING ITSELF INTO A LARGE ALTOSTRATUS AND CIRROSTRATUS DECK.
TO THE SOUTHWEST...850MB WINDS HAVE BEEN INCREASING OUT OF THE SOUTH
OVER TEXAS DOWNSTREAM OF THE UPPER LOW...BRINGING GULF OF MEXICO
MOISTURE NORTHWARD TOWARDS OKLAHOMA AS SEEN IN GOES PRECIPITABLE
WATER PLOTS.
TODAY AND TONIGHT...A WARM ADVECTION PATTERN LOOKS TO DEVELOP OVER
THE AREA IN RESPONSE TO THE UPPER TROUGH OVER SOUTHWEST CANADA
SPLITTING INTO TWO...WHERE ONE PIECE MARCHES EAST INTO NORTHWEST
ONTARIO AND NORTH DAKOTA BY 12Z SATURDAY. THE OTHER PIECE DIGS SOUTH
TOWARDS THE LAS VEGAS AREA...CAUSING THE CURRENT UPPER LOW IN
ARIZONA TO GET PUSHED EAST INTO NEW MEXICO. CONDITIONS WILL REMAIN
DRY TODAY GIVEN PLENTIFUL DRY AIR AROUND AS SEEN FROM 00Z SOUNDINGS.
IN FACT...SKIES SHOULD STAY CLEAR TO 00Z. WINDS ARE LIKELY TO
INCREASE...THOUGH...AS THE PRESSURE GRADIENT TIGHTENS UP BEHIND THE
DEPARTING SURFACE RIDGE. TONIGHT IS A DIFFERENT STORY. THE SOUTHERLY
RETURN FLOW SEEN OCCURRING OVER TEXAS NOW IS FORECAST TO EXPAND AND
INTENSIFY TONIGHT...RUNNING FROM DEEP SOUTH TEXAS INTO KANSAS...THEN
NORTHEAST INTO THE FORECAST AREA BY 06Z. 850MB WINDS IN THIS ZONE
ARE PROGGED BETWEEN 40-50 KT. PRECIPITABLE WATER VALUES RESPOND BY
JUMPING FROM AROUND 0.25 INCH AT 00Z TO 0.5-0.8 INCHES AT 12Z...
HIGHEST IN THE SOUTHEASTERN PORTION OF THE FORECAST AREA. 0.75
INCHES REPRESENTS 200 PERCENT OF NORMAL. AS THE DEEPER MOISTURE
ISENTROPICALLY LIFTS INTO THE COLDER AIRMASS OVER THE AREA...
ANTICIPATING PRECIPITATION TO BREAK OUT. MODELS ARE IN VERY GOOD
AGREEMENT ON THIS OCCURRING...WITH THE HIGHEST CONSENSUS OVER THE
SOUTHEASTERN TWO-THIRDS OF THE AREA. PLACED 80-100 PERCENT CHANCES
IN THE SOUTHEAST HALF...THEN TRENDED DRIER HEADING UP TO THE
NORTHWEST INTO LOWER PRECIPITABLE WATER VALUES. P-TYPE A LITTLE
TRICKY AS A SURGE OF WARMER AIR ALSO ACCOMPANIES THE MOISTURE SURGE.
850MB TEMPS ARE PROGGED TO WARM TO 0-2C OVER THE SAME AREA WITH THE
HIGHEST PRECIPITABLE WATER. SHOULD BE MOSTLY A RAIN/SNOW SCENARIO AS
SURFACE TEMPERATURES WARM OVERNIGHT...BUT COULD SEE FREEZING RAIN
TOO IF SURFACE TEMPERATURES HAVE NOT WARMED ABOVE FREEZING OR FROM
NOT ENOUGH ICE PRESENT ALOFT YET. ANY SNOW/ICE ACCUMULATION LOOKS
MINIMAL TONIGHT. HAVE NOT INCLUDED ANY FREEZING RAIN/DRIZZLE BECAUSE
UNCERTAINTY IS JUST TOO HIGH.
SATURDAY THROUGH SUNDAY...MODELS ARE ALL IN VERY GOOD AGREEMENT
KICKING OUT THE UPPER LOW FROM NEW MEXICO AT 12Z SATURDAY NORTHEAST
AS A SHEARING OUT SHORTWAVE. IN ADDITION...THE SHORTWAVE SHOULD GET
ACCELERATED NORTHEAST OVERNIGHT TONIGHT INTO SUNDAY IN RESPONSE TO
MORE TROUGHING DROPPING SOUTH INTO THE NORTHERN PLAINS. THERE ARE
SOME SLIGHT DIFFERENCES WITH RESPECT TO THE ASSOCIATED SURFACE LOW
WITH THE SHORTWAVE...WHICH HAS IMPLICATIONS ON THE TRACK AND
INTENSITY OF THE DEFORMATION PRECIPITATION ON THE NORTH SIDE OF THE
LOW. THE 02.00Z GFS IS THE WEAKEST WITH THE LOW AND FURTHEST
SOUTHEAST...HAVING IT TRACK ACROSS NORTHEAST ILLINOIS AT 12Z SUNDAY.
THE 02.00Z NAM IS FARTHEST NORTHWEST AND FASTEST...CROSSING THE BAY
OF GREEN BAY AT 12Z SUNDAY. THE 02.00Z ECMWF/UKMET IS A COMPROMISE.
FOR NOW FOLLOWED THE COMPROMISE APPROACH...SINCE THE GFS SOLUTION IS
PLAUSIBLE IF MORE CONVECTION CAN OCCUR THAN CURRENTLY PROGGED DOWN
OVER THE SOUTHERN PLAINS. ON THE FLIP SIDE...THERE HAS BEEN QUITE A
BIT OF CONSISTENCY WITH THE ECMWF AND NAM SOLUTIONS. SATURDAY
MORNING SHOULD BE A CONTINUATION OF PRECIPITATION FROM AFTER
MIDNIGHT TONIGHT...DUE TO PERSISTENT ISENTROPIC LIFT. PRECIPITATION
THEN LOOKS TO INTENSIFY IN THE AFTERNOON...PARTICULARLY OVER THE
NORTHWEST HALF OF THE FORECAST AREA...AS THE DEFORMATION AREA OF THE
SURFACE LOW APPROACHES. HEAVIEST PRECIPITATION STILL LOOKS TO OCCUR
SATURDAY EVENING WHEN STRONGEST LOW TO MID-LEVEL FRONTOGENESIS MOVES
ACROSS. IN FACT...CROSS-SECTIONS SHOW THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...SUGGESTING CONVECTIVE
ELEMENTS ARE POSSIBLE. AGAIN...THE HEAVIEST PRECIPITATION LOOKS TO
END UP OVER THE NORTHWEST HALF OF THE FORECAST AREA. WITH SNOW TO
WATER RATIOS LIKELY TO END UP SOMEWHERE AROUND 10 TO 1 AS AN AVERAGE
FOR SATURDAY AND SATURDAY NIGHT...COMBINED WITH QPF AMOUNTS AROUND
0.60 OF AN INCH...TOTAL SNOWFALL WOULD COME OUT TO AROUND 6 INCHES.
GIVEN THAT THE NORTHWEST HALF OF THE FORECAST AREA HAS NOT REALLY
SEEN ITS FIRST SIGNIFICANT SNOW...HAVE ISSUED A WINTER STORM WATCH
FOR THAT AREA. BIGGEST CONCERN OF THE WATCH IS SATURDAY AFTERNOON
AND EVENING...ESPECIALLY TOO WITH THE HOLIDAY SHOPPING/TRAVEL TAKING
PLACE. FOR THE SOUTHEAST END OF THE FORECAST AREA...MAJORITY OF THE
PRECIPITATION MAY FALL AS RAIN OR A RAIN/SNOW MIX AS A SURGE OF WARM
AIR COMES IN. NEW 02.06Z NAM SUGGESTS EVEN A WARMER SURGE. LA CROSSE
COUNTY KEPT OUT OF THE WATCH DUE TO RAIN MIX EXPECTED ON SATURDAY.
FOR BOTH SATURDAY AND SATURDAY NIGHT...INCREASED PRECIPITATION
CHANCES ANYWHERE FROM 10 TO 30 PERCENT GIVEN GOOD CONTINUITY AND
MODEL AGREEMENT. PRECIPITATION SHOULD DIMINISH PRETTY QUICK ON
SUNDAY...THOUGH DID KEEP SOME 20 PERCENT CHANCES GOING IN THE
AFTERNOON FOR CENTRAL WISCONSIN WITH LINGERING UPPER TROUGHING.
CERTAINLY WILL BE COOLER ON SUNDAY WITH SNOW COVER AND 850MB TEMPS
OF -6 TO -8C MOVING IN.
SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO THE TROUGHING COMING
INTO THE NORTHERN PLAINS ON SUNDAY. GOOD AGREEMENT ON THIS UPPER
TROUGH HEADING EAST INTO THE FORECAST AREA ON MONDAY. HOWEVER...ALL
OF THE BETTER FORCING/MOISTURE APPEAR TO HEAD TO THE NORTH OF THE
AREA. AS SUCH...HAVE CONTINUED A DRY SUNDAY NIGHT AND ONLY KEPT A 20
PERCENT CHANCE IN FOR TAYLOR/CLARK COUNTIES ON MONDAY. COULD SEE
CHANCES BEING COMPLETELY REMOVED FOR MONDAY IF TRENDS CONTINUE.
ALTHOUGH PRECIPITATION LOOKS LIMITED...THE COLD AIR WILL NOT BE.
850MB TEMPS ARE PROGGED TO FALL EVEN FURTHER...DROPPING TO AT LEAST
-8 TO -12C BY 00Z TUESDAY...IF NOT A LITTLE COOLER THAN THAT AS
NOTED BY THE 02.00Z GFS. WENT WITH A BLEND OF GUIDANCE FOR LOWS AND
HIGHS DURING THIS PERIOD...WHICH END UP 5 TO 10 DEGREES COLDER THAN
SATURDAY NIGHT AND SUNDAY.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
347 AM CST FRI DEC 2 2011
AFTER A BUSY EARLY PART TO THE WEEKEND FOR THE WEATHER...MUCH OF THE
EARLY AND MIDDLE PORTION OF NEXT WEEK LOOK QUIET AND COOL. 02.00Z
ECMWF/CANADIAN/GFS/GFS ENSEMBLES ARE IN GOOD AGREEMENT FOR MUCH OF
THE LONG TERM FORECAST INDICATING THE TROUGHING THAT WAS OVER THE
AREA MONDAY LINGERING INTO TUESDAY...THEN JUST GRADUAL DEEP
TROUGHING FORMING OVER MUCH OF CANADA INTO THE NORTHERN U.S. HEADING
INTO THURSDAY. THIS TYPE OF PATTERN SUGGESTS LITTLE MOISTURE TO WORK
WITH AND AS SUCH MODEL QPF FORECASTS ARE PRETTY MUCH NOTHING. NEXT
REAL CHANCE OF PRECIPITATION COMES MAYBE ON THURSDAY NIGHT WITH SOME
HINTS OF SHORTWAVE TROUGHING DIGGING INTO THE WESTERN U.S....
RESULTING IN A WARM ADVECTION PATTERN DOWNSTREAM. STILL...THE
PRECIPITATION CHANCE LOOKS PRETTY SMALL. THE BIG THING IS
TEMPERATURES. 850MB TEMPS ARE PROGGED TO DROP TO ONLY SLOWLY RECOVER
TO -6 TO -8C ON WEDNESDAY...THEN FALL BACK TO -12 TO -18C OR SO FOR
THURSDAY. THEREFORE...TEMPERATURES ARE FORECAST TO STAY BELOW
NORMAL. FOLLOWED A CONSENSUS OF GUIDANCE FOR TEMPERATURES. CANNOT
RULE A PERIOD OF SOME BELOW ZERO TEMPERATURES FOR LOWS TOO...
ESPECIALLY FOR SOME OF THE TYPICAL COLD SPOTS.
&&
.AVIATION...THROUGH 18Z SATURDAY
1131 AM CST FRI DEC 2 2011
HIGH PRESSURE SLIDES EAST OF THE AREA TONIGHT AS AN AREA OF LOW
PRESSURE GETS ORGANIZED ACROSS THE SOUTHERN PLAINS. BIGGEST
CONCERN IS ON PRECIPITATION ONSET TIME AND LOWERING CEILINGS AFTER
09Z TONIGHT. VFR CONDITIONS EXPECTED THROUGH 09Z...AFTER WHICH LOW
LEVEL MOISTURE GETS PULLED NORTHWARD AHEAD OF THE LOW. CEILINGS
WILL LIKELY LOWER AND PRECIPITATION BREAK OUT BETWEEN 09Z-12Z.
HOWEVER FEEL CEILINGS WILL REMAIN IN THE VFR CATEGORY UNTIL AT
LEAST 12Z. FIRST SURGE OF PRECIPITATION LOOKS TO BE IN THE FORM OF
LIGHT SNOW AND HAVE TRENDED TAFS IN THIS DIRECTION WITH MVFR
CEILINGS AND VISIBILITIES. WITH WARMER AIR BEING PULLED
NORTHWARD...DID MIX WITH SNOW WITH SOME RAIN AT KLSE AFTER 16Z.
LATER SHIFTS WILL HAVE TO WATCH FOR LOWER CEILINGS/VISIBILITIES IN
THE 10Z-18Z TIME FRAME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
347 AM CST FRI DEC 2 2011
WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR WIZ017-029-032>034.
MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR MNZ079-086>088-094-095.
IA...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
550 AM CST FRI DEC 2 2011
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
347 AM CST FRI DEC 2 2011
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR AFTER MIDNIGHT TONIGHT
THROUGH SUNDAY MORNING AND POSSIBLE HAZARDS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH OVER SOUTHWEST CANADA...RIDGING OUT
AHEAD OVER THE NORTHERN PLAINS INTO MANITOBA...AND TROUGHING OVER
THE LAKE MICHIGAN AREA. ALSO OF NOTE IS IN THE SOUTHERN STREAM OF AN
UPPER LOW OVER THE DESERT SOUTHWEST. THE FORECAST AREA LIES IN
SUBSIDENCE IMMEDIATELY BEHIND THE LAKE MICHIGAN TROUGH...PROMOTING
HIGH PRESSURE AT THE SURFACE. IN FACT...THE SUBSIDENCE AND DRYING
HAS BEEN ENOUGH TO RESULT IN CLEAR SKIES OVER THE AREA. UPSTREAM 00Z
SOUNDINGS FROM INL AND ABR REFLECT THE DRYING WELL WITH PRECIPITABLE
WATER VALUES UNDER TWO TENTHS OF AN INCH. THE COMBINATION OF THE
CLEAR SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES TO DROP INTO
THE TEENS TO MID 20S. TO THE NORTHWEST...A STREAM OF UPPER LEVEL
MOISTURE CAN BE SEEN ACROSS THE NORTHERN PLAINS INTO SOUTH CENTRAL
CANADA ON WATER VAPOR....AHEAD OF THE UPPER TROUGH THERE...WHICH IS
MANIFESTING ITSELF INTO A LARGE ALTOSTRATUS AND CIRROSTRATUS DECK.
TO THE SOUTHWEST...850MB WINDS HAVE BEEN INCREASING OUT OF THE SOUTH
OVER TEXAS DOWNSTREAM OF THE UPPER LOW...BRINGING GULF OF MEXICO
MOISTURE NORTHWARD TOWARDS OKLAHOMA AS SEEN IN GOES PRECIPITABLE
WATER PLOTS.
TODAY AND TONIGHT...A WARM ADVECTION PATTERN LOOKS TO DEVELOP OVER
THE AREA IN RESPONSE TO THE UPPER TROUGH OVER SOUTHWEST CANADA
SPLITTING INTO TWO...WHERE ONE PIECE MARCHES EAST INTO NORTHWEST
ONTARIO AND NORTH DAKOTA BY 12Z SATURDAY. THE OTHER PIECE DIGS SOUTH
TOWARDS THE LAS VEGAS AREA...CAUSING THE CURRENT UPPER LOW IN
ARIZONA TO GET PUSHED EAST INTO NEW MEXICO. CONDITIONS WILL REMAIN
DRY TODAY GIVEN PLENTIFUL DRY AIR AROUND AS SEEN FROM 00Z SOUNDINGS.
IN FACT...SKIES SHOULD STAY CLEAR TO 00Z. WINDS ARE LIKELY TO
INCREASE...THOUGH...AS THE PRESSURE GRADIENT TIGHTENS UP BEHIND THE
DEPARTING SURFACE RIDGE. TONIGHT IS A DIFFERENT STORY. THE SOUTHERLY
RETURN FLOW SEEN OCCURRING OVER TEXAS NOW IS FORECAST TO EXPAND AND
INTENSIFY TONIGHT...RUNNING FROM DEEP SOUTH TEXAS INTO KANSAS...THEN
NORTHEAST INTO THE FORECAST AREA BY 06Z. 850MB WINDS IN THIS ZONE
ARE PROGGED BETWEEN 40-50 KT. PRECIPITABLE WATER VALUES RESPOND BY
JUMPING FROM AROUND 0.25 INCH AT 00Z TO 0.5-0.8 INCHES AT 12Z...
HIGHEST IN THE SOUTHEASTERN PORTION OF THE FORECAST AREA. 0.75
INCHES REPRESENTS 200 PERCENT OF NORMAL. AS THE DEEPER MOISTURE
ISENTROPICALLY LIFTS INTO THE COLDER AIRMASS OVER THE AREA...
ANTICIPATING PRECIPITATION TO BREAK OUT. MODELS ARE IN VERY GOOD
AGREEMENT ON THIS OCCURRING...WITH THE HIGHEST CONSENSUS OVER THE
SOUTHEASTERN TWO-THIRDS OF THE AREA. PLACED 80-100 PERCENT CHANCES
IN THE SOUTHEAST HALF...THEN TRENDED DRIER HEADING UP TO THE
NORTHWEST INTO LOWER PRECIPITABLE WATER VALUES. P-TYPE A LITTLE
TRICKY AS A SURGE OF WARMER AIR ALSO ACCOMPANIES THE MOISTURE SURGE.
850MB TEMPS ARE PROGGED TO WARM TO 0-2C OVER THE SAME AREA WITH THE
HIGHEST PRECIPITABLE WATER. SHOULD BE MOSTLY A RAIN/SNOW SCENARIO AS
SURFACE TEMPERATURES WARM OVERNIGHT...BUT COULD SEE FREEZING RAIN
TOO IF SURFACE TEMPERATURES HAVE NOT WARMED ABOVE FREEZING OR FROM
NOT ENOUGH ICE PRESENT ALOFT YET. ANY SNOW/ICE ACCUMULATION LOOKS
MINIMAL TONIGHT. HAVE NOT INCLUDED ANY FREEZING RAIN/DRIZZLE BECAUSE
UNCERTAINTY IS JUST TOO HIGH.
SATURDAY THROUGH SUNDAY...MODELS ARE ALL IN VERY GOOD AGREEMENT
KICKING OUT THE UPPER LOW FROM NEW MEXICO AT 12Z SATURDAY NORTHEAST
AS A SHEARING OUT SHORTWAVE. IN ADDITION...THE SHORTWAVE SHOULD GET
ACCELERATED NORTHEAST OVERNIGHT TONIGHT INTO SUNDAY IN RESPONSE TO
MORE TROUGHING DROPPING SOUTH INTO THE NORTHERN PLAINS. THERE ARE
SOME SLIGHT DIFFERENCES WITH RESPECT TO THE ASSOCIATED SURFACE LOW
WITH THE SHORTWAVE...WHICH HAS IMPLICATIONS ON THE TRACK AND
INTENSITY OF THE DEFORMATION PRECIPITATION ON THE NORTH SIDE OF THE
LOW. THE 02.00Z GFS IS THE WEAKEST WITH THE LOW AND FURTHEST
SOUTHEAST...HAVING IT TRACK ACROSS NORTHEAST ILLINOIS AT 12Z SUNDAY.
THE 02.00Z NAM IS FARTHEST NORTHWEST AND FASTEST...CROSSING THE BAY
OF GREEN BAY AT 12Z SUNDAY. THE 02.00Z ECMWF/UKMET IS A COMPROMISE.
FOR NOW FOLLOWED THE COMPROMISE APPROACH...SINCE THE GFS SOLUTION IS
PLAUSIBLE IF MORE CONVECTION CAN OCCUR THAN CURRENTLY PROGGED DOWN
OVER THE SOUTHERN PLAINS. ON THE FLIP SIDE...THERE HAS BEEN QUITE A
BIT OF CONSISTENCY WITH THE ECMWF AND NAM SOLUTIONS. SATURDAY
MORNING SHOULD BE A CONTINUATION OF PRECIPITATION FROM AFTER
MIDNIGHT TONIGHT...DUE TO PERSISTENT ISENTROPIC LIFT. PRECIPITATION
THEN LOOKS TO INTENSIFY IN THE AFTERNOON...PARTICULARLY OVER THE
NORTHWEST HALF OF THE FORECAST AREA...AS THE DEFORMATION AREA OF THE
SURFACE LOW APPROACHES. HEAVIEST PRECIPITATION STILL LOOKS TO OCCUR
SATURDAY EVENING WHEN STRONGEST LOW TO MID-LEVEL FRONTOGENESIS MOVES
ACROSS. IN FACT...CROSS-SECTIONS SHOW THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...SUGGESTING CONVECTIVE
ELEMENTS ARE POSSIBLE. AGAIN...THE HEAVIEST PRECIPITATION LOOKS TO
END UP OVER THE NORTHWEST HALF OF THE FORECAST AREA. WITH SNOW TO
WATER RATIOS LIKELY TO END UP SOMEWHERE AROUND 10 TO 1 AS AN AVERAGE
FOR SATURDAY AND SATURDAY NIGHT...COMBINED WITH QPF AMOUNTS AROUND
0.60 OF AN INCH...TOTAL SNOWFALL WOULD COME OUT TO AROUND 6 INCHES.
GIVEN THAT THE NORTHWEST HALF OF THE FORECAST AREA HAS NOT REALLY
SEEN ITS FIRST SIGNIFICANT SNOW...HAVE ISSUED A WINTER STORM WATCH
FOR THAT AREA. BIGGEST CONCERN OF THE WATCH IS SATURDAY AFTERNOON
AND EVENING...ESPECIALLY TOO WITH THE HOLIDAY SHOPPING/TRAVEL TAKING
PLACE. FOR THE SOUTHEAST END OF THE FORECAST AREA...MAJORITY OF THE
PRECIPITATION MAY FALL AS RAIN OR A RAIN/SNOW MIX AS A SURGE OF WARM
AIR COMES IN. NEW 02.06Z NAM SUGGESTS EVEN A WARMER SURGE. LA CROSSE
COUNTY KEPT OUT OF THE WATCH DUE TO RAIN MIX EXPECTED ON SATURDAY.
FOR BOTH SATURDAY AND SATURDAY NIGHT...INCREASED PRECIPITATION
CHANCES ANYWHERE FROM 10 TO 30 PERCENT GIVEN GOOD CONTINUITY AND
MODEL AGREEMENT. PRECIPITATION SHOULD DIMINISH PRETTY QUICK ON
SUNDAY...THOUGH DID KEEP SOME 20 PERCENT CHANCES GOING IN THE
AFTERNOON FOR CENTRAL WISCONSIN WITH LINGERING UPPER TROUGHING.
CERTAINLY WILL BE COOLER ON SUNDAY WITH SNOW COVER AND 850MB TEMPS
OF -6 TO -8C MOVING IN.
SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO THE TROUGHING COMING
INTO THE NORTHERN PLAINS ON SUNDAY. GOOD AGREEMENT ON THIS UPPER
TROUGH HEADING EAST INTO THE FORECAST AREA ON MONDAY. HOWEVER...ALL
OF THE BETTER FORCING/MOISTURE APPEAR TO HEAD TO THE NORTH OF THE
AREA. AS SUCH...HAVE CONTINUED A DRY SUNDAY NIGHT AND ONLY KEPT A 20
PERCENT CHANCE IN FOR TAYLOR/CLARK COUNTIES ON MONDAY. COULD SEE
CHANCES BEING COMPLETELY REMOVED FOR MONDAY IF TRENDS CONTINUE.
ALTHOUGH PRECIPITATION LOOKS LIMITED...THE COLD AIR WILL NOT BE.
850MB TEMPS ARE PROGGED TO FALL EVEN FURTHER...DROPPING TO AT LEAST
-8 TO -12C BY 00Z TUESDAY...IF NOT A LITTLE COOLER THAN THAT AS
NOTED BY THE 02.00Z GFS. WENT WITH A BLEND OF GUIDANCE FOR LOWS AND
HIGHS DURING THIS PERIOD...WHICH END UP 5 TO 10 DEGREES COLDER THAN
SATURDAY NIGHT AND SUNDAY.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
347 AM CST FRI DEC 2 2011
AFTER A BUSY EARLY PART TO THE WEEKEND FOR THE WEATHER...MUCH OF THE
EARLY AND MIDDLE PORTION OF NEXT WEEK LOOK QUIET AND COOL. 02.00Z
ECMWF/CANADIAN/GFS/GFS ENSEMBLES ARE IN GOOD AGREEMENT FOR MUCH OF
THE LONG TERM FORECAST INDICATING THE TROUGHING THAT WAS OVER THE
AREA MONDAY LINGERING INTO TUESDAY...THEN JUST GRADUAL DEEP
TROUGHING FORMING OVER MUCH OF CANADA INTO THE NORTHERN U.S. HEADING
INTO THURSDAY. THIS TYPE OF PATTERN SUGGESTS LITTLE MOISTURE TO WORK
WITH AND AS SUCH MODEL QPF FORECASTS ARE PRETTY MUCH NOTHING. NEXT
REAL CHANCE OF PRECIPITATION COMES MAYBE ON THURSDAY NIGHT WITH SOME
HINTS OF SHORTWAVE TROUGHING DIGGING INTO THE WESTERN U.S....
RESULTING IN A WARM ADVECTION PATTERN DOWNSTREAM. STILL...THE
PRECIPITATION CHANCE LOOKS PRETTY SMALL. THE BIG THING IS
TEMPERATURES. 850MB TEMPS ARE PROGGED TO DROP TO ONLY SLOWLY RECOVER
TO -6 TO -8C ON WEDNESDAY...THEN FALL BACK TO -12 TO -18C OR SO FOR
THURSDAY. THEREFORE...TEMPERATURES ARE FORECAST TO STAY BELOW
NORMAL. FOLLOWED A CONSENSUS OF GUIDANCE FOR TEMPERATURES. CANNOT
RULE A PERIOD OF SOME BELOW ZERO TEMPERATURES FOR LOWS TOO...
ESPECIALLY FOR SOME OF THE TYPICAL COLD SPOTS.
&&
.AVIATION...TODAY INTO SATURDAY
550 AM CST FRI DEC 2 2011
A RIDGE OF HIGH PRESSURE WILL DRIFT ACROSS ACROSS THE UPPER MIDWEST
TODAY INTO THIS EVENING...BRINGING GOOD VFR CONDITIONS TO THE TAF
SITES THRU MIDNIGHT TONIGHT. A COLD FRONT WILL BE MOVING ACROSS THE
NORTHERN PLAINS TONIGHT WHILE LOW PRESSURE DEVELOPS IN THE SOUTHERN
PLAINS. INCREASING LOW/MID LEVEL MOISTURE WILL QUICKLY SURGE NORTH
AHEAD OF THE LOW AND FRONT...WITH CIGS EXPECTED TO DEVELOP/LOWER
OVER THE TAF SITES LATE TONIGHT. MAIN QUESTION IS HOW QUICKLY WILL
CIGS LOWER INTO MVFR AND -SN OR -SN/-RA MOVE INTO THE TAF SITES LATE
TONIGHT/SAT MORNING. NO CLEAR MODEL SIGNAL ON THE TIMING. GIVEN THE
INITIAL DEEP/DRY AIRMASS OVER THE AREA JUST INTRODUCED VCSH AND
LOWERED CIGS INTO THE 3K-4K FT RANGE AT KRST/KLSE TAFS LATE TONIGHT
TOWARD THE END OF THE TAF PERIOD. CIGS/VSBYS WILL CONTINUE TO LOWER
SAT AS MOISTURE/LIFT CONTINUE TO INCREASE OVER THE AREA AHEAD OF THE
APPROACHING LOW...WITH IFR CONDITIONS EXPECTED BY SAT AFTERNOON.
AIRMASS WILL BE COLD ENOUGH FOR MAINLY SNOW AT KRST AND A SN/RA MIX
AT KLSE. ACCUMULATING SNOWS EXPECTED AT KRST/KLSE...ESPECIALLY BY
SAT AFTERNOON AND FOR SAT EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
347 AM CST FRI DEC 2 2011
WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR WIZ017-029-032>034.
MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR MNZ079-086>088-094-095.
IA...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
348 AM CST FRI DEC 2 2011
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
347 AM CST FRI DEC 2 2011
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR AFTER MIDNIGHT TONIGHT
THROUGH SUNDAY MORNING AND POSSIBLE HAZARDS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH OVER SOUTHWEST CANADA...RIDGING OUT
AHEAD OVER THE NORTHERN PLAINS INTO MANITOBA...AND TROUGHING OVER
THE LAKE MICHIGAN AREA. ALSO OF NOTE IS IN THE SOUTHERN STREAM OF AN
UPPER LOW OVER THE DESERT SOUTHWEST. THE FORECAST AREA LIES IN
SUBSIDENCE IMMEDIATELY BEHIND THE LAKE MICHIGAN TROUGH...PROMOTING
HIGH PRESSURE AT THE SURFACE. IN FACT...THE SUBSIDENCE AND DRYING
HAS BEEN ENOUGH TO RESULT IN CLEAR SKIES OVER THE AREA. UPSTREAM 00Z
SOUNDINGS FROM INL AND ABR REFLECT THE DRYING WELL WITH PRECIPITABLE
WATER VALUES UNDER TWO TENTHS OF AN INCH. THE COMBINATION OF THE
CLEAR SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES TO DROP INTO
THE TEENS TO MID 20S. TO THE NORTHWEST...A STREAM OF UPPER LEVEL
MOISTURE CAN BE SEEN ACROSS THE NORTHERN PLAINS INTO SOUTH CENTRAL
CANADA ON WATER VAPOR....AHEAD OF THE UPPER TROUGH THERE...WHICH IS
MANIFESTING ITSELF INTO A LARGE ALTOSTRATUS AND CIRROSTRATUS DECK.
TO THE SOUTHWEST...850MB WINDS HAVE BEEN INCREASING OUT OF THE SOUTH
OVER TEXAS DOWNSTREAM OF THE UPPER LOW...BRINGING GULF OF MEXICO
MOISTURE NORTHWARD TOWARDS OKLAHOMA AS SEEN IN GOES PRECIPITABLE
WATER PLOTS.
TODAY AND TONIGHT...A WARM ADVECTION PATTERN LOOKS TO DEVELOP OVER
THE AREA IN RESPONSE TO THE UPPER TROUGH OVER SOUTHWEST CANADA
SPLITTING INTO TWO...WHERE ONE PIECE MARCHES EAST INTO NORTHWEST
ONTARIO AND NORTH DAKOTA BY 12Z SATURDAY. THE OTHER PIECE DIGS SOUTH
TOWARDS THE LAS VEGAS AREA...CAUSING THE CURRENT UPPER LOW IN
ARIZONA TO GET PUSHED EAST INTO NEW MEXICO. CONDITIONS WILL REMAIN
DRY TODAY GIVEN PLENTIFUL DRY AIR AROUND AS SEEN FROM 00Z SOUNDINGS.
IN FACT...SKIES SHOULD STAY CLEAR TO 00Z. WINDS ARE LIKELY TO
INCREASE...THOUGH...AS THE PRESSURE GRADIENT TIGHTENS UP BEHIND THE
DEPARTING SURFACE RIDGE. TONIGHT IS A DIFFERENT STORY. THE SOUTHERLY
RETURN FLOW SEEN OCCURRING OVER TEXAS NOW IS FORECAST TO EXPAND AND
INTENSIFY TONIGHT...RUNNING FROM DEEP SOUTH TEXAS INTO KANSAS...THEN
NORTHEAST INTO THE FORECAST AREA BY 06Z. 850MB WINDS IN THIS ZONE
ARE PROGGED BETWEEN 40-50 KT. PRECIPITABLE WATER VALUES RESPOND BY
JUMPING FROM AROUND 0.25 INCH AT 00Z TO 0.5-0.8 INCHES AT 12Z...
HIGHEST IN THE SOUTHEASTERN PORTION OF THE FORECAST AREA. 0.75
INCHES REPRESENTS 200 PERCENT OF NORMAL. AS THE DEEPER MOISTURE
ISENTROPICALLY LIFTS INTO THE COLDER AIRMASS OVER THE AREA...
ANTICIPATING PRECIPITATION TO BREAK OUT. MODELS ARE IN VERY GOOD
AGREEMENT ON THIS OCCURRING...WITH THE HIGHEST CONSENSUS OVER THE
SOUTHEASTERN TWO-THIRDS OF THE AREA. PLACED 80-100 PERCENT CHANCES
IN THE SOUTHEAST HALF...THEN TRENDED DRIER HEADING UP TO THE
NORTHWEST INTO LOWER PRECIPITABLE WATER VALUES. P-TYPE A LITTLE
TRICKY AS A SURGE OF WARMER AIR ALSO ACCOMPANIES THE MOISTURE SURGE.
850MB TEMPS ARE PROGGED TO WARM TO 0-2C OVER THE SAME AREA WITH THE
HIGHEST PRECIPITABLE WATER. SHOULD BE MOSTLY A RAIN/SNOW SCENARIO AS
SURFACE TEMPERATURES WARM OVERNIGHT...BUT COULD SEE FREEZING RAIN
TOO IF SURFACE TEMPERATURES HAVE NOT WARMED ABOVE FREEZING OR FROM
NOT ENOUGH ICE PRESENT ALOFT YET. ANY SNOW/ICE ACCUMULATION LOOKS
MINIMAL TONIGHT. HAVE NOT INCLUDED ANY FREEZING RAIN/DRIZZLE BECAUSE
UNCERTAINTY IS JUST TOO HIGH.
SATURDAY THROUGH SUNDAY...MODELS ARE ALL IN VERY GOOD AGREEMENT
KICKING OUT THE UPPER LOW FROM NEW MEXICO AT 12Z SATURDAY NORTHEAST
AS A SHEARING OUT SHORTWAVE. IN ADDITION...THE SHORTWAVE SHOULD GET
ACCELERATED NORTHEAST OVERNIGHT TONIGHT INTO SUNDAY IN RESPONSE TO
MORE TROUGHING DROPPING SOUTH INTO THE NORTHERN PLAINS. THERE ARE
SOME SLIGHT DIFFERENCES WITH RESPECT TO THE ASSOCIATED SURFACE LOW
WITH THE SHORTWAVE...WHICH HAS IMPLICATIONS ON THE TRACK AND
INTENSITY OF THE DEFORMATION PRECIPITATION ON THE NORTH SIDE OF THE
LOW. THE 02.00Z GFS IS THE WEAKEST WITH THE LOW AND FURTHEST
SOUTHEAST...HAVING IT TRACK ACROSS NORTHEAST ILLINOIS AT 12Z SUNDAY.
THE 02.00Z NAM IS FARTHEST NORTHWEST AND FASTEST...CROSSING THE BAY
OF GREEN BAY AT 12Z SUNDAY. THE 02.00Z ECMWF/UKMET IS A COMPROMISE.
FOR NOW FOLLOWED THE COMPROMISE APPROACH...SINCE THE GFS SOLUTION IS
PLAUSIBLE IF MORE CONVECTION CAN OCCUR THAN CURRENTLY PROGGED DOWN
OVER THE SOUTHERN PLAINS. ON THE FLIP SIDE...THERE HAS BEEN QUITE A
BIT OF CONSISTENCY WITH THE ECMWF AND NAM SOLUTIONS. SATURDAY
MORNING SHOULD BE A CONTINUATION OF PRECIPITATION FROM AFTER
MIDNIGHT TONIGHT...DUE TO PERSISTENT ISENTROPIC LIFT. PRECIPITATION
THEN LOOKS TO INTENSIFY IN THE AFTERNOON...PARTICULARLY OVER THE
NORTHWEST HALF OF THE FORECAST AREA...AS THE DEFORMATION AREA OF THE
SURFACE LOW APPROACHES. HEAVIEST PRECIPITATION STILL LOOKS TO OCCUR
SATURDAY EVENING WHEN STRONGEST LOW TO MID-LEVEL FRONTOGENESIS MOVES
ACROSS. IN FACT...CROSS-SECTIONS SHOW THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...SUGGESTING CONVECTIVE
ELEMENTS ARE POSSIBLE. AGAIN...THE HEAVIEST PRECIPITATION LOOKS TO
END UP OVER THE NORTHWEST HALF OF THE FORECAST AREA. WITH SNOW TO
WATER RATIOS LIKELY TO END UP SOMEWHERE AROUND 10 TO 1 AS AN AVERAGE
FOR SATURDAY AND SATURDAY NIGHT...COMBINED WITH QPF AMOUNTS AROUND
0.60 OF AN INCH...TOTAL SNOWFALL WOULD COME OUT TO AROUND 6 INCHES.
GIVEN THAT THE NORTHWEST HALF OF THE FORECAST AREA HAS NOT REALLY
SEEN ITS FIRST SIGNIFICANT SNOW...HAVE ISSUED A WINTER STORM WATCH
FOR THAT AREA. BIGGEST CONCERN OF THE WATCH IS SATURDAY AFTERNOON
AND EVENING...ESPECIALLY TOO WITH THE HOLIDAY SHOPPING/TRAVEL TAKING
PLACE. FOR THE SOUTHEAST END OF THE FORECAST AREA...MAJORITY OF THE
PRECIPITATION MAY FALL AS RAIN OR A RAIN/SNOW MIX AS A SURGE OF WARM
AIR COMES IN. NEW 02.06Z NAM SUGGESTS EVEN A WARMER SURGE. LA CROSSE
COUNTY KEPT OUT OF THE WATCH DUE TO RAIN MIX EXPECTED ON SATURDAY.
FOR BOTH SATURDAY AND SATURDAY NIGHT...INCREASED PRECIPITATION
CHANCES ANYWHERE FROM 10 TO 30 PERCENT GIVEN GOOD CONTINUITY AND
MODEL AGREEMENT. PRECIPITATION SHOULD DIMINISH PRETTY QUICK ON
SUNDAY...THOUGH DID KEEP SOME 20 PERCENT CHANCES GOING IN THE
AFTERNOON FOR CENTRAL WISCONSIN WITH LINGERING UPPER TROUGHING.
CERTAINLY WILL BE COOLER ON SUNDAY WITH SNOW COVER AND 850MB TEMPS
OF -6 TO -8C MOVING IN.
SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO THE TROUGHING COMING
INTO THE NORTHERN PLAINS ON SUNDAY. GOOD AGREEMENT ON THIS UPPER
TROUGH HEADING EAST INTO THE FORECAST AREA ON MONDAY. HOWEVER...ALL
OF THE BETTER FORCING/MOISTURE APPEAR TO HEAD TO THE NORTH OF THE
AREA. AS SUCH...HAVE CONTINUED A DRY SUNDAY NIGHT AND ONLY KEPT A 20
PERCENT CHANCE IN FOR TAYLOR/CLARK COUNTIES ON MONDAY. COULD SEE
CHANCES BEING COMPLETELY REMOVED FOR MONDAY IF TRENDS CONTINUE.
ALTHOUGH PRECIPITATION LOOKS LIMITED...THE COLD AIR WILL NOT BE.
850MB TEMPS ARE PROGGED TO FALL EVEN FURTHER...DROPPING TO AT LEAST
-8 TO -12C BY 00Z TUESDAY...IF NOT A LITTLE COOLER THAN THAT AS
NOTED BY THE 02.00Z GFS. WENT WITH A BLEND OF GUIDANCE FOR LOWS AND
HIGHS DURING THIS PERIOD...WHICH END UP 5 TO 10 DEGREES COLDER THAN
SATURDAY NIGHT AND SUNDAY.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
347 AM CST FRI DEC 2 2011
AFTER A BUSY EARLY PART TO THE WEEKEND FOR THE WEATHER...MUCH OF THE
EARLY AND MIDDLE PORTION OF NEXT WEEK LOOK QUIET AND COOL. 02.00Z
ECMWF/CANADIAN/GFS/GFS ENSEMBLES ARE IN GOOD AGREEMENT FOR MUCH OF
THE LONG TERM FORECAST INDICATING THE TROUGHING THAT WAS OVER THE
AREA MONDAY LINGERING INTO TUESDAY...THEN JUST GRADUAL DEEP
TROUGHING FORMING OVER MUCH OF CANADA INTO THE NORTHERN U.S. HEADING
INTO THURSDAY. THIS TYPE OF PATTERN SUGGESTS LITTLE MOISTURE TO WORK
WITH AND AS SUCH MODEL QPF FORECASTS ARE PRETTY MUCH NOTHING. NEXT
REAL CHANCE OF PRECIPITATION COMES MAYBE ON THURSDAY NIGHT WITH SOME
HINTS OF SHORTWAVE TROUGHING DIGGING INTO THE WESTERN U.S....
RESULTING IN A WARM ADVECTION PATTERN DOWNSTREAM. STILL...THE
PRECIPITATION CHANCE LOOKS PRETTY SMALL. THE BIG THING IS
TEMPERATURES. 850MB TEMPS ARE PROGGED TO DROP TO ONLY SLOWLY RECOVER
TO -6 TO -8C ON WEDNESDAY...THEN FALL BACK TO -12 TO -18C OR SO FOR
THURSDAY. THEREFORE...TEMPERATURES ARE FORECAST TO STAY BELOW
NORMAL. FOLLOWED A CONSENSUS OF GUIDANCE FOR TEMPERATURES. CANNOT
RULE A PERIOD OF SOME BELOW ZERO TEMPERATURES FOR LOWS TOO...
ESPECIALLY FOR SOME OF THE TYPICAL COLD SPOTS.
&&
.AVIATION...
1110 PM CST THU DEC 1 2011
HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY...BUT QUICKLY SHIFT EAST FRI NIGHT. CLEAR SKIES
AND LIGHT WINDS OVERNIGHT...WITH VFR CONDITIONS CONTINUING FOR MUCH
OF FRIDAY. LOOK FOR SOME AFTERNOON GUSTINESS THANKS TO SUN AIDED
MIXING...MORE SO FOR KRST.
CLOUDS WILL START TO RETURN FRI EVENING...THICKENING AND LOWERING
OVERNIGHT AS A STORM SYSTEM OVER THE SOUTHERN PLAINS STARTS TO
IMPACT THE AREA. MVFR/IFR CEILINGS THEN LOOK LIKELY FOR SAT/SAT
NIGHT AS THE SYSTEM PASSES TO THE SOUTH/EAST. RA/SN CAN ALSO BE
EXPECTED...WITH SEVERAL INCHES OF SNOW ACCUMULATION AND IMPACTS TO
VSBY HEIGHTENED SAT EVENING. CURRENT STORM TRACK WOULD FAVOR KRST
FOR MORE SNOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
347 AM CST FRI DEC 2 2011
WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR WIZ017-029-032>034.
MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR MNZ079-086>088-094-095.
IA...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1059 PM MST THU DEC 1 2011
.DISCUSSION...THE VISIBILITIES HAVE IMPROVED SOME OVER THE AREA
BETWEEN KCYS AND KLAR...INCLUDING THE SOUTHERN LARAMIE RANGE. A
SURFACE TROUGH CONTINUES TO DEVELOP OVER FAR EASTERN WYOMING THE
REST OF TONIGHT. THE RESULTING INCREASED SURFACE PRESSURE GRADIENT
SHOULD INCREASE MIXING AND LIMIT THE POTENTIAL FOR DENSE FOG THE
REST OF TONIGHT. FOR THAT REASON...THE DENSE FOG ADVISORY HAS BEEN
CANCELLED FOR THE AREA BETWEEN KCYS AND THE SOUTHERN LARAMIE RANGE.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 1015 PM MST THU DEC 1 2011/...
.AVIATION...06Z TAFS
ONLY PROBLEM AREA THIS EVENING IS GOING TO BE CHEYENNE. LATEST
SATELLITE SHOWING AN EXPANDING AREA OF STRATUS ALONG AND EAST OF
THE SOUTHERN LARAMIE RANGE. THIS IS BRINGING LIFR CNDITIONS TO
KCYS WITH THE EASTERN SLOPES OF THE SOUTHERN LARAMIE RANGE
OBSCURED. LATEST HRRR GUIDANCE KEEPS THIS LAYER IN THROUGH 09Z
WITH CLEARING AFTERWARDS. DECIDED TO KEEP LIFR/IFR CONDITIONS
GOING THROUGH 12Z AS THE AREA IS STILL EXPANDING.
NEXT FRONT LOOKS TO DROP INTO SOUTHEAST WYOMING FRIDAY AFTERNOON
WITH DECREASING FLIGHT CONDITIONS ONCE AGAIN FRIDAY EVENING INTO
SATURDAY.
CLAYCOMB
&&
.PREV DISCUSSION... /ISSUED 905 PM MST THU DEC 1 2011/
UPDATE...
WYDOT WEBCAMS NOW SHOW DENSE FOG FROM CHEYENNE TO AT LEAST THE
INTERSTATE 80 SUMMIT. SEEING REDUCED VISIBILITIES ON INTERSTATE 25
AS WELL OVER WYO HILL. WENT AHEAD WITH A DENSE FOG ADVISORY
THROUGH 12Z/5AM. WINDS FORECAST TO BECOME MORE WESTERLY AFTER THAT
TIME...WHICH SHOULD DISSIPATE OUT THE FOG. UPDATES HAVE BEEN
SENT.
PREV DISCUSSION... /ISSUED 827 PM MST THU DEC 1 2011/
UPDATE...
STARTING TO SEE FOG DEVELOPING OVER THE LARAMIE SUMMIT ON
INTERSTATE 80 BETWEEN CHEYENNE AND LARAMIE. WENT AHEAD AND ISSUED
SPS FOR VISIBILITIES DOWN TO A HALF MILE. WILL WAIT ANOTHER FEW
MINUTES TO SEE IF IT GETS ANY DENSER. LATEST 11-3.9U SATELLITE
IMAGERY SHOWING A FAIRLY CONFINED AREA OF STRATUS OVER THE SUMMIT
AT THIS TIME. WILL CONTINUE TO MONITOR TO SEE IF IT EXPANDS
ANYMORE BEFORE ISSUING A DENSE FOG ADVISORY.
CLAYCOMB
&&
PREV DISCUSSION... /ISSUED 347 PM MST THU DEC 1 2011/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT.
TONIGHT...SATELLITE IMAGERY...WSR-88D LOOPS...SURFACE OBSERVATIONS
INDICATE SNOW HAS NEARLY ENDED ACROSS OUR COUNTIES. BASED ON THE NAM
AND GFS SOLUTIONS...WILL LEAVE IN SOME LOW TOKEN POPS FOR THIS
EVENING ACROSS THE SIERRA MADRE...SNOWY AND SOUTHERN LARAMIE RANGES.
PRIMARY CHALLENGE TONIGHT WILL BE MINIMUM TEMPERATURES AS SKIES
CLEAR ALONG WITH FRESH SNOWPACK ALONG WITH LIGHT WINDS.
SURFACE LEE TROUGHING WILL DEVELOP LATE TONIGHT IN OUR COUNTIES IN
RESPONSE TO NEXT APPROACHING SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST. HOWEVER...THIS MINIMAL MIXING IS NOT EXPECTED TO HAVE
MUCH EFFECT ON LOW TEMPERATURES OVERNIGHT. HAVE UNDERCUT GUIDANCE
TEMPERATURES AT MOST LOCATIONS...ESPECIALLY ACROSS THE LARAMIE
VALLEY WHERE CLEAR SKIES...FRESH SNOWPACK...LIGHT WINDS AND THE
ARCTIC AIRMASS WILL PROMOTE EXCELLENT RADIATIONAL
COOLING...PARTICULARLY IN THE HIGH MOUNTAIN VALLEYS AND RIVER VALLEY
LOCATIONS.
FRIDAY...NEXT SHORTWAVE TROUGH ALOFT FAST ON THE HEELS OF THE
CURRENT SHORTWAVE TROUGH. WILL SEE A COLD FRONTAL PASSAGE ACROSS OUR
COUNTIES DURING THE DAY...PRECEDED BY A SURFACE TROUGH PASSAGE.
EXPECT SNOW SHOWERS IN THE AFTERNOON OVER THE NORTHERN LARAMIE
RANGE...SIERRA MADRE RANGE AND SNOWY RANGE DUE TO OROGRAPHICS...DRY
ELSEWHERE.
FRIDAY NIGHT...SHORTWAVE TROUGH ALOFT PASSES ACROSS OUR COUNTIES
WITH THE DEEPER SATURATED LAYER ACROSS OUR WESTERN COUNTIES WEST OF
INTERSTATE 25...COINCIDENT WITH THE BEST UPWARD VERTICAL MOTION
ASSOCIATED WITH THE SHORTWAVE TROUGH. WILL NEED TO WATCH EXPECTED
SNOWFALL AMOUNTS WEST OF A DOUGLAS TO CHEYENNE LINE FOR POSSIBLE
WINTER WEATHER ADVISORY CRITERIA. FOR NOW...HAVE INCREASED SNOW
CHANCES SIGNIFICANTLY ALONG AND WEST OF THE LARAMIE RANGE WITH NEAR
100 PERCENT POPS ACROSS THE HIGHER PEAKS OF THE NORTHERN LARAMIE...
SIERRA MADRE AND SNOWY RANGES...AND LESSER POPS FURTHER EAST AWAY
FROM THE GREATEST DYNAMICS. ANOTHER REINFORCING SHOT OF COLD AIR
ADVECTS IN FROM THE NORTH. WILL INCLUDE AREAS OF BLOWING SNOW IN
AREAS WHERE WINDS AND SNOW LOOK FAVORABLE.
SATURDAY...AS OCCURRED TODAY...SNOW GRADUALLY ENDS FROM NORTH TO
SOUTH AS THE SHORTWAVE TROUGH ALOFT MOVES ACROSS COLORADO. LOOKS
LIKE THE MOTHERLODE OF THE COLD AIRMASS MOVES OVERHEAD IN OUR
COUNTIES WITH PROGGED 700 MB TEMPERATURES NEAR -18 CELSIUS...
THUS HIGH TEMPERATURES ONLY IN THE TEENS AND 20S...WHICH MAY BE
OPTIMISTIC IF CLOUD OPACITY...THICKNESS...IS WELL PRONOUNCED.
SATURDAY NIGHT...NEXT SHORTWAVE TROUGH ALOFT...A HEALTHY LOOKING
ALBERTA CLIPPER SYSTEM...TRACKS OVER MONTANA AND NORTH DAKOTA...
INDUCING SURFACE LOW PRESSURE TO STRENGTHEN ACROSS NORTH DAKOTA AND
INCREASING THE PRESSURE GRADIENT ACROSS OUR COUNTIES. BLUSTERY AND
COLD NIGHT FOR OUR COUNTIES WITH MINIMUM TEMPERATURES IN THE SINGLE
DIGITS BELOW ZERO AND ABOVE ZERO...WITH A FEW LOWER TEENS...AND
DECENT DOWNSLOPE WEST WINDS. WIND CHILL TEMPERATURES OF 15 BELOW
ZERO TO 30 BELOW ZERO ON TAP ACROSS MUCH OF CARBON AND ALBANY
COUNTIES.
LONG TERM...SUNDAY THROUGH THURSDAY...UPPER LEVEL TROUGH WILL DIVE
SOUTH INTO THE NORTHERN PLAINS FROM CANADA ON SUNDAY. THE ASSOCIATED
COLD FRONT WILL MOVE ACROSS THE AREA ON SUNDAY MORNING...THUS
EXPECT MAX TEMPS TO OCCUR SOMETIME IN THE MORNING WITH TEMPS THEN
FALLING THROUGH THE DAY BEHIND THE FRONT. LIGHT SNOW WILL OCCUR
BEHIND THE FRONT WITH NOT MUCH ACCUMULATION EXPECTED OUTSIDE OF
THE MOUNTAINS. VERY COLD TEMPS WILL OCCUR SUNDAY NIGHT AS SKIES
CLEAR SOMEWHAT AND THE UPPER TROUGH MOVES OVERHEAD...USHERING IN
700MB TEMPS OF -20 TO -25C. MONDAY WILL REMAIN QUITE
CHILLY...ALTHOUGH SOME MODERATION IS POSSIBLE WITH MOSTLY CLEAR
SKIES. SFC HIGH PRESSURE BEHIND THE FRONT WILL SLIDE SOUTH OF THE
AREA ON MONDAY NIGHT WITH THE LEESIDE SFC TROUGH DEEPENING THRU
TUESDAY MORNING. WESTERLY WINDS WILL THUS INCREASE AS THIS
OCCURS...AND WILL PERSIST THROUGH TUESDAY NIGHT AHEAD OF THE NEXT
COLD FRONT AND UPPER LEVEL SYSTEM EXPECTED TO AFFECT THE FORECAST
AREA WEDNESDAY AND THURSDAY. SOME LIGHT SNOW IS POSSIBLE WITH
THIS SYSTEM ACROSS MUCH OF THE FORECAST AREA.
FIRE WEATHER...NO FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM/AVIATION...RJM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1015 PM MST THU DEC 1 2011
.AVIATION...06Z TAFS
ONLY PROBLEM AREA THIS EVENING IS GOING TO BE CHEYENNE. LATEST
SATELLITE SHOWING AN EXPANDING AREA OF STRATUS ALONG AND EAST OF
THE SOUTHERN LARAMIE RANGE. THIS IS BRINGING LIFR CNDITIONS TO
KCYS WITH THE EASTERN SLOPES OF THE SOUTHERN LARAMIE RANGE
OBSCURED. LATEST HRRR GUIDANCE KEEPS THIS LAYER IN THROUGH 09Z
WITH CLEARING AFTERWARDS. DECIDED TO KEEP LIFR/IFR CONDITIONS
GOING THROUGH 12Z AS THE AREA IS STILL EXPANDING.
NEXT FRONT LOOKS TO DROP INTO SOUTHEAST WYOMING FRIDAY AFTERNOON
WITH DECREASING FLIGHT CONDITIONS ONCE AGAIN FRIDAY EVENING INTO
SATURDAY.
CLAYCOMB
&&
.PREV DISCUSSION... /ISSUED 905 PM MST THU DEC 1 2011/
UPDATE...
WYDOT WEBCAMS NOW SHOW DENSE FOG FROM CHEYENNE TO AT LEAST THE
INTERSTATE 80 SUMMIT. SEEING REDUCED VISIBILITIES ON INTERSTATE 25
AS WELL OVER WYO HILL. WENT AHEAD WITH A DENSE FOG ADVISORY
THROUGH 12Z/5AM. WINDS FORECAST TO BECOME MORE WESTERLY AFTER THAT
TIME...WHICH SHOULD DISSIPATE OUT THE FOG. UPDATES HAVE BEEN
SENT.
PREV DISCUSSION... /ISSUED 827 PM MST THU DEC 1 2011/
UPDATE...
STARTING TO SEE FOG DEVELOPING OVER THE LARAMIE SUMMIT ON
INTERSTATE 80 BETWEEN CHEYENNE AND LARAMIE. WENT AHEAD AND ISSUED
SPS FOR VISIBILITIES DOWN TO A HALF MILE. WILL WAIT ANOTHER FEW
MINUTES TO SEE IF IT GETS ANY DENSER. LATEST 11-3.9U SATELLITE
IMAGERY SHOWING A FAIRLY CONFINED AREA OF STRATUS OVER THE SUMMIT
AT THIS TIME. WILL CONTINUE TO MONITOR TO SEE IF IT EXPANDS
ANYMORE BEFORE ISSUING A DENSE FOG ADVISORY.
CLAYCOMB
&&
PREV DISCUSSION... /ISSUED 347 PM MST THU DEC 1 2011/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT.
TONIGHT...SATELLITE IMAGERY...WSR-88D LOOPS...SURFACE OBSERVATIONS
INDICATE SNOW HAS NEARLY ENDED ACROSS OUR COUNTIES. BASED ON THE NAM
AND GFS SOLUTIONS...WILL LEAVE IN SOME LOW TOKEN POPS FOR THIS
EVENING ACROSS THE SIERRA MADRE...SNOWY AND SOUTHERN LARAMIE RANGES.
PRIMARY CHALLENGE TONIGHT WILL BE MINIMUM TEMPERATURES AS SKIES
CLEAR ALONG WITH FRESH SNOWPACK ALONG WITH LIGHT WINDS.
SURFACE LEE TROUGHING WILL DEVELOP LATE TONIGHT IN OUR COUNTIES IN
RESPONSE TO NEXT APPROACHING SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST. HOWEVER...THIS MINIMAL MIXING IS NOT EXPECTED TO HAVE
MUCH EFFECT ON LOW TEMPERATURES OVERNIGHT. HAVE UNDERCUT GUIDANCE
TEMPERATURES AT MOST LOCATIONS...ESPECIALLY ACROSS THE LARAMIE
VALLEY WHERE CLEAR SKIES...FRESH SNOWPACK...LIGHT WINDS AND THE
ARCTIC AIRMASS WILL PROMOTE EXCELLENT RADIATIONAL
COOLING...PARTICULARLY IN THE HIGH MOUNTAIN VALLEYS AND RIVER VALLEY
LOCATIONS.
FRIDAY...NEXT SHORTWAVE TROUGH ALOFT FAST ON THE HEELS OF THE
CURRENT SHORTWAVE TROUGH. WILL SEE A COLD FRONTAL PASSAGE ACROSS OUR
COUNTIES DURING THE DAY...PRECEDED BY A SURFACE TROUGH PASSAGE.
EXPECT SNOW SHOWERS IN THE AFTERNOON OVER THE NORTHERN LARAMIE
RANGE...SIERRA MADRE RANGE AND SNOWY RANGE DUE TO OROGRAPHICS...DRY
ELSEWHERE.
FRIDAY NIGHT...SHORTWAVE TROUGH ALOFT PASSES ACROSS OUR COUNTIES
WITH THE DEEPER SATURATED LAYER ACROSS OUR WESTERN COUNTIES WEST OF
INTERSTATE 25...COINCIDENT WITH THE BEST UPWARD VERTICAL MOTION
ASSOCIATED WITH THE SHORTWAVE TROUGH. WILL NEED TO WATCH EXPECTED
SNOWFALL AMOUNTS WEST OF A DOUGLAS TO CHEYENNE LINE FOR POSSIBLE
WINTER WEATHER ADVISORY CRITERIA. FOR NOW...HAVE INCREASED SNOW
CHANCES SIGNIFICANTLY ALONG AND WEST OF THE LARAMIE RANGE WITH NEAR
100 PERCENT POPS ACROSS THE HIGHER PEAKS OF THE NORTHERN LARAMIE...
SIERRA MADRE AND SNOWY RANGES...AND LESSER POPS FURTHER EAST AWAY
FROM THE GREATEST DYNAMICS. ANOTHER REINFORCING SHOT OF COLD AIR
ADVECTS IN FROM THE NORTH. WILL INCLUDE AREAS OF BLOWING SNOW IN
AREAS WHERE WINDS AND SNOW LOOK FAVORABLE.
SATURDAY...AS OCCURRED TODAY...SNOW GRADUALLY ENDS FROM NORTH TO
SOUTH AS THE SHORTWAVE TROUGH ALOFT MOVES ACROSS COLORADO. LOOKS
LIKE THE MOTHERLODE OF THE COLD AIRMASS MOVES OVERHEAD IN OUR
COUNTIES WITH PROGGED 700 MB TEMPERATURES NEAR -18 CELSIUS...
THUS HIGH TEMPERATURES ONLY IN THE TEENS AND 20S...WHICH MAY BE
OPTIMISTIC IF CLOUD OPACITY...THICKNESS...IS WELL PRONOUNCED.
SATURDAY NIGHT...NEXT SHORTWAVE TROUGH ALOFT...A HEALTHY LOOKING
ALBERTA CLIPPER SYSTEM...TRACKS OVER MONTANA AND NORTH DAKOTA...
INDUCING SURFACE LOW PRESSURE TO STRENGTHEN ACROSS NORTH DAKOTA AND
INCREASING THE PRESSURE GRADIENT ACROSS OUR COUNTIES. BLUSTERY AND
COLD NIGHT FOR OUR COUNTIES WITH MINIMUM TEMPERATURES IN THE SINGLE
DIGITS BELOW ZERO AND ABOVE ZERO...WITH A FEW LOWER TEENS...AND
DECENT DOWNSLOPE WEST WINDS. WIND CHILL TEMPERATURES OF 15 BELOW
ZERO TO 30 BELOW ZERO ON TAP ACROSS MUCH OF CARBON AND ALBANY
COUNTIES.
LONG TERM...SUNDAY THROUGH THURSDAY...UPPER LEVEL TROUGH WILL DIVE
SOUTH INTO THE NORTHERN PLAINS FROM CANADA ON SUNDAY. THE ASSOCIATED
COLD FRONT WILL MOVE ACROSS THE AREA ON SUNDAY MORNING...THUS
EXPECT MAX TEMPS TO OCCUR SOMETIME IN THE MORNING WITH TEMPS THEN
FALLING THROUGH THE DAY BEHIND THE FRONT. LIGHT SNOW WILL OCCUR
BEHIND THE FRONT WITH NOT MUCH ACCUMULATION EXPECTED OUTSIDE OF
THE MOUNTAINS. VERY COLD TEMPS WILL OCCUR SUNDAY NIGHT AS SKIES
CLEAR SOMEWHAT AND THE UPPER TROUGH MOVES OVERHEAD...USHERING IN
700MB TEMPS OF -20 TO -25C. MONDAY WILL REMAIN QUITE
CHILLY...ALTHOUGH SOME MODERATION IS POSSIBLE WITH MOSTLY CLEAR
SKIES. SFC HIGH PRESSURE BEHIND THE FRONT WILL SLIDE SOUTH OF THE
AREA ON MONDAY NIGHT WITH THE LEESIDE SFC TROUGH DEEPENING THRU
TUESDAY MORNING. WESTERLY WINDS WILL THUS INCREASE AS THIS
OCCURS...AND WILL PERSIST THROUGH TUESDAY NIGHT AHEAD OF THE NEXT
COLD FRONT AND UPPER LEVEL SYSTEM EXPECTED TO AFFECT THE FORECAST
AREA WEDNESDAY AND THURSDAY. SOME LIGHT SNOW IS POSSIBLE WITH
THIS SYSTEM ACROSS MUCH OF THE FORECAST AREA.
FIRE WEATHER...NO FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 5 AM FRIDAY FOR WYZ116-WYZ117-WYZ118.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM/AVIATION...RJM
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
310 AM EST SUN DEC 4 2011
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN CENTERED NORTH OF THE REGION THROUGH
EARLY THIS WEEK AS A WEAK TROUGH OF LOW PRESSURE LINGERS OFFSHORE.
A COLD FRONT WILL IMPACT THE AREA DURING MID WEEK FOLLOWED BY HIGH
PRESSURE FOR LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
IT IS CONSIDERABLY WARMER ACROSS SOUTHEAST SOUTH CAROLINA AND
SOUTHEAST GEORGIA EARLY THIS MORNING WITH 24 HOUR TEMPERATURE
CHANGES AVERAGING BETWEEN +15 AND +20 DEGREES PER 04/07Z REGIONAL
OBSERVATIONS. THIS TREND WILL CONTINUE THROUGH SUNRISE WITH LITTLE
CHANGE IN TEMPERATURES EXPECTED.
DEEP LAYERED HIGH PRESSURE WILL HOLD FIRM ACROSS THE CAROLINAS AND
EASTERN GEORGIA TODAY AS AN IMPRESSIVE UPPER LEVEL TROUGH DOMINATES
MUCH OF THE WESTERN AND CENTRAL PORTIONS OF THE COUNTRY. CLOUD
COVER IS EXPECTED TO THICKEN THROUGH THE DAY AS 290-295K
ISENTROPIC LIFT PERSISTS ATOP THE LOW-LEVEL SURFACE WEDGE.
ALTHOUGH THE LOWEST 4000 FT OF THE COLUMN WILL BE QUITE MOIST...
THE REMAINDER OF THE LOWER TROPOSPHERE WILL REMAIN TOO DRY TO
SUPPORT MUCH IN THE WAY OF SIGNIFICANT RAINFALL. ALTHOUGH A FEW
SPRINKLES COULD OCCUR AT VARIOUS LOCATIONS THROUGH THE DAY...
ESPECIALLY AT THE COAST CLOSER TO THE COASTAL TROUGH...THE
PROSPECTS FOR MEASURABLE RAINFALL ARE TOO LOW TO JUSTIFY ANY
MENTION OF RAIN CHANCES THROUGH SUNSET.
HIGH TEMPERATURES WILL BE TEMPERED BY A STRENGTHENING ONSHORE FLOW
AND INCREASED CLOUD COVER. MODEL SOUNDINGS SUGGEST A SLIGHT
LOWERING OF OUR HIGH TEMPERATURE FORECAST IS NEEDED FOR MOST
LOCATIONS...BUT ONLY BY 1-2 DEGREES. STILL EXPECT AT OR SLIGHTLY
ABOVE NORMAL TEMPERATURES FOR EARLY DECEMBER WITH HIGHS GENERALLY
TOPPING OUT IN THE MID-UPPER 60S. IT SHOULD BE NOTED THAT SOME
GRIDDED GUIDANCE SUGGESTS TEMPERATURES MAY BE CONFINED TO THE
LOWER-MID 60S. WILL HAVE TO SEE HOW IF THESE TRENDS CONTINUE AND
IF THEY DO A SLIGHTLY LOWERING MAY BE CONSIDERED LATER TODAY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
THE UPPER RIDGE WILL BEGIN TO RAPIDLY ERODE TONIGHT AS THE UPPER
TROUGH TO THE WEST DRAWS CLOSER. THE LOW-LEVEL LOOKS TO HOLD FIRM
WITH THE COASTAL TROUGH LURKING JUST OFFSHORE FOR MUCH OF THE
NIGHT. CONTINUED ISENTROPIC LIFT WILL HELP MAINTAIN QUITE A BIT OF
CLOUD COVER OVERNIGHT WITH AN OUTSIDE CHANCE FOR A BRIEF SPRINKLE
OR LIGHT SHOWER POTENTIALLY MOVING ONSHORE AT THE COAST. WE
CONTINUE TO FAVOR A DRY FORECAST WITH GRIDDED POPS GENERALLY
RANGING BETWEEN 5-10 PERCENT. SIMILAR TO THIS MORNING...THE
INCREASED CLOUD COVER AND A BIT MORE WIND WILL YIELD A RELATIVELY
WARM NIGHT WITH LOWS RANGING FROM THE LOWER 50S INLAND TO THE
UPPER 50S/NEAR 60 AT THE COAST. THERE IS SOME CONCERN FOR FOG TO
DEVELOP AFTER MIDNIGHT AS STRATUS TRIES TO BUILD DOWN...BUT
CONFIDENCE THIS FAR OUT IS NOT HIGH ENOUGH TO JUSTIFY A MENTION
ATTM.
AT MID LEVELS...A STRONG RIDGE WILL DOMINATE THE SOUTHEAST MONDAY
AND TUESDAY...WHILE SURFACE HIGH PRESSURE SLOWLY RETREATS INTO THE
ATLANTIC. TEMPERATURES WILL BE ABOVE NORMAL THE FIRST HALF OF THE
WEEK...EXCEPT ALONG THE IMMEDIATE COAST WHERE SURFACE WINDS WILL
GENERALLY BE FROM THE SOUTHEAST DURING THIS PERIOD. THERE IS A
CHANCE OF A FEW SHOWERS AROUND BY TUESDAY AS A COLD FRONT MAKES SLOW
PROGRESS INTO NORTHERN GEORGIA AND UPSTATE SOUTH CAROLINA...BUT MOST
OF THE ACTIVITY SHOULD REMAIN TO THE NORTHWEST OF THE AREA.
THE FORECAST BECOMES MUCH MORE DIFFICULT FOR WEDNESDAY. THE MAIN
QUESTION WILL BE THE SPEED OF THE FRONT APPROACHING FROM THE WEST.
THE 00Z GFS ESSENTIALLY STALLS THE FRONT FROM UPSTATE SOUTH CAROLINA
TO CENTRAL GEORGIA...KEEPING THE FORECAST AREA ON THE WARM SIDE OF
THE SYSTEM. HOWEVER...BOTH THE CMC AND ECMWF ARE A LITTLE MORE
PROGRESSIVE AND HAVE THE FRONT MOVING SLOWLY THROUGH THE CWA LATER
WEDNESDAY. THE DIFFERENCES IN FRONTAL TIMING ARE MAINLY MODULATED BY
THE EXPECTED DEVELOPMENT OF A SURFACE LOW PRESSURE AREA ALONG THE
FRONT. THE GFS IS FURTHEST WEST WITH THE DEVELOPMENT...AND ACTUALLY
BRINGS A LOW OUT OF THE EASTERN GULF OF MEXICO INTO GEORGIA THURSDAY
MORNING AND DOES NOT DRAG THE FRONT THROUGH THE CWA UNTIL THURSDAY.
RIGHT NOW THIS IS AN OUTLIER...AND NOT ONLY DO THE OTHER GLOBAL
MODELS BRING THE FRONT THROUGH FASTER...THERE ARE SEVERAL MEMBERS OF
THE GFS ENSEMBLE WHICH ARE ALSO FASTER. THEREFORE...I HAVE GONE MORE
WITH A MIDDLE OF THE ROAD SOLUTION...KEEPING MOST OF THE AREA ON THE
WARM SIDE WEDNESDAY...BUT WITH THE FRONT KNOCKING ON THE DOOR BY
AFTERNOON.
I HAVE CONTINUED CHANCE POPS ON WEDNESDAY ACROSS THE AREA...BUT
FRONTAL TIMING MAY CAUSE AN INCREASE OR DECREASE OF THESE VALUES
WITH TIME.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BASED ON THE THINKING MENTIONED ABOVE...I AM GOING FOR A SCENARIO
WITH A FRONTAL PASSAGE WEDNESDAY NIGHT ACROSS THE CWA FROM WEST TO
EAST. THIS IS NOT MUCH DIFFERENT THAN THE PREVIOUS FORECAST WAS
SHOWING...ALTHOUGH I DID HAVE TO MAKE SOME APPROPRIATE ADJUSTMENTS
TO THE TEMPS AND DEW POINTS TO ACCOUNT FOR THE SPEED OF THE FRONT.
FOR PRECIP...DUE TO THE UNCERTAINTY IN THE TIMING I AM JUST GOING
WITH CHANCE POPS WEDNESDAY NIGHT. THOSE MIGHT HAVE TO BE RAISED IN A
DAY OR TWO WHEN THE TIMING IS A BIT MORE CERTAIN.
COOLER AND DRIER WEATHER WILL MOVE IN BEHIND THE FRONT FOR THE END
OF THE WEEK.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
EXTREMELY TRICKY AVIATION FORECAST FOR THE NEXT 24 HOURS. OF MOST
IMPORTANCE IS THE NEXT 6-9 HOURS WHERE THE GREATEST AVIATION
IMPACTS CAN BE EXPECTED. SATELLITE SHOWS LOW/MID-LEVEL CLOUD DECKS
RAPIDLY EXPANDING ACROSS THE REGION COINCIDENT WITH INCREASING
ISENTROPIC ASSENT. EXPECT MVFR CIGS TO OVERSPREAD KCHS/KSAV WITHIN
THE NEXT FEW HOURS WITH BOTH RUC AND NAM SOUNDINGS INDICATING A
POTENTIAL FOR IFR CIGS AFTER 09Z...IF NOT SOONER. GIVEN CURRENT
CIG TRENDS SOUTH OF THE ALTAMAHA RIVER...WE SUSPECT KSAV HAS THE
HIGHEST CHANCE FOR SEEING IFR CONDITIONS OVER THE NEXT FEW HOURS
SO WILL INTRODUCE A TEMPO GROUP FROM 09-12Z TO TAKE THIS INTO
ACCOUNT. CONFIDENCE IS NOT AS HIGH AT KCHS SO WILL ONLY UTILIZE A
TEMPO 09-12Z FOR LOW-END MVFR CIGS AT THIS POINT. SHOULD TRENDS
SUGGEST IFR CONDITIONS WILL DEVELOP AND AMENDMENT WILL BE ISSUED.
LOW CONFIDENCE ON EXACTLY WHEN CIGS WILL RISE BACK TO VFR LEVELS
WITH GUIDANCE ESSENTIALLY SPLIT. SOME KEEP CIGS IN MVFR TERRITORY
FOR MUCH OF THE 06Z TAF PERIOD WHILE OTHERS BRING CONDITIONS BACK
TO VFR BY LATE MORNING/EARLY AFTERNOON. WILL TAKE THE MORE
CONSERVATIVE ROUTE AT THIS POINT GIVEN ALL OF THE UNCERTAINTIES
AND SHOW VFR CIGS RETURNING TO BOTH TERMINALS BY 15-16Z.
EXTENDED AVIATION OUTLOOK...CAN NOT RULE OUT MVFR CIGS ON
OCCASION AT THE TERMINALS MONDAY AND TUESDAY MORNINGS WITH THE
ONSHORE FLOW POTENTIALLY BRINGING IN A MARINE STRATUS DECK...BUT
THE BEST CHANCE OF REDUCED CIGS/VSBYS WILL BE LATER WEDNESDAY INTO
THURSDAY MORNING WITH THE COLD FRONT PASSAGE.
&&
.MARINE...
WINDS AND SEAS CONTINUE TO BUILD ACROSS THE WATERS EARLY THIS
MORNING. THE COASTAL THROUGH RECENTLY PUSHED WEST OF BUOY 41004
SO EXPECT WINDS TO GRADUALLY DIMINISH SOUTH OF EDISTO BEACH OVER
THE NEXT FEW HOURS. A PINCHED GRADIENT WILL LIKELY CONTINUE OVER
THE CHARLESTON COUNTY COASTAL WATERS WHERE WINDS OF 15-20 KT WITH
HIGHER GUSTS WILL LIKELY PERSIST THROUGH AT LEAST LATE MORNING.
BUOY AND WW4 OUTPUT SUGGEST SEAS RANGE FROM 4-6 NEARSHORE AND 6-8
FT OFFSHORE. THE SMALL CRAFT ADVISORY LOOKS WELL PLACED FOR ALL
BUT THE CHARLESTON HARBOR.
THE PRESSURE GRADIENT IS EXPECTED TO RE-TIGHTEN THIS EVENING AS
INLAND AREAS COOL AND THE COASTAL THROUGH MEANDERS EVEN CLOSER TO
THE BEACHES. THE MOST ENHANCED GRADIENT LOOKS TO OCCUR OVER THE
FAVORED CHARLESTON COUNTY COASTAL WATERS WHERE SPEEDS COULD REACH
AS HIGH AS 15-20 KT. THE FAVORED NORTHEAST FETCH WILL KEEP SEAS
ELEVATED...BUT THE LATEST WW4 OUTPUT KEEPS SEAS BELOW 6 FT OVER
THE NEARSHORE WATERS. SEAS LOOK TO REMAIN ABOVE 6 FT OVER THE
GEORGIA OFFSHORE LEG THROUGH THE NIGHT.
WINDS SHOULD BE GENERALLY 15 KNOTS OR LESS OUT OF THE EAST AND
SOUTHEAST MONDAY AND TUESDAY WITH HIGH PRESSURE IN THE WESTERN
ATLANTIC SLOW TO MOVE EASTWARD. WINDS WILL PICK UP WEDNESDAY AHEAD
OF THE APPROACHING COLD FRONT...THEN STAY UP BEHIND THE FRONT ON
THURSDAY...WITH WINDS VEERING TO WEST AND NORTHWEST. SCAS ARE
EXPECTED AT SOME POINT MID WEEK.
SEAS WILL BE A BIT MORE OF A PROBLEM DUE TO THE EXTENDED FETCH FROM
THE EAST. HEIGHTS OF 6 FEET OR MORE ARE EXPECTED IN THE OUTER
GEORGIA WATERS FOR A FEW DAYS NEXT WEEK...WHILE SEAS WILL BE COMING
UP IN THE NEARSHORE WATERS BUT MAY NOT REACH THE SCA CRITERIA OF 6
FEET.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ350-
352-354.
SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR AMZ374.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1231 AM EST SUN DEC 4 2011
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN CENTERED NORTH OF THE REGION THROUGH
EARLY NEXT WEEK...WHILE A WEAK TROUGH OF LOW PRESSURE WILL DEVELOP
AND PERSIST ACROSS THE NEARBY COASTAL WATERS DURING THIS TIME. A
COLD FRONT WILL IMPACT THE AREA DURING MID WEEK...FOLLOWED BY HIGH
PRESSURE FOR LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SATELLITE SHOWS LOW/MID-LEVEL CLOUDS RAPIDLY EXPANDING. SHOULD SEE
MOST AREAS GO MOSTLY CLOUDY IF NOT CLOUDY OVER THE NEXT FEW HOURS.
WILL NEED TO MAKE SOME ADJUSTMENT TO TEMPERATURES WITH THE EARLY
MORNING UPDATE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/...
MODELS ARE GENERALLY IN GOOD AGREEMENT...SHOWING A DEEP LAYERED
RIDGE EXTENDING FROM THE EASTERN GULF OF MEXICO TO NOVA SCOTIA AND A
BROAD POSITIVELY TILTED TROUGH FROM THE NORTHERN PLAINS INTO THE
FOUR CORNERS REGION ON SUNDAY. THIS SYNOPTIC PATTERN WILL GRADUALLY
SHIFT EASTWARD THROUGH THE SHORT TERM PERIOD.
SUNDAY...SURFACE HIGH PRESSURE WILL CONTINUE TO WEDGE INTO THE
REGION FROM THE NORTH. SKIES SHOULD BE PARTLY TO MOSTLY CLOUDY FOR
THE MAJORITY OF THE DAY WITH AMPLE MOISTURE TRAPPED BENEATH A MID
LEVEL INVERSION ACCORDING TO MODEL SOUNDINGS. THESE CLOUDS WILL
LIKELY STICK AROUND THROUGH SUNDAY NIGHT AS THE LOW LEVEL FLOW
REMAINS ONSHORE. DAYTIME TEMPERATURES MIGHT BE HELD DOWN A BIT DUE
TO THE CLOUD COVER...BUT STILL EXPECT HIGHS TO REACH THE UPPER 60S.
TEMPERATURES SUNDAY NIGHT WILL ONLY FALL INTO THE UPPER 40S OR LOWER
50S GIVEN THE CLOUD COVER AS WELL.
MONDAY...THE SURFACE RIDGE WILL SHIFT OFFSHORE ALLOWING THE LOW
LEVEL FLOW TO VEER SOUTHEASTERLY. WHILE LOW LEVEL MOISTURE WILL
CONTINUE TO ADVECT INTO THE AREA MAINTAINING PARTLY TO PERHAPS
MOSTLY CLOUDY SKIES...THE MOISTURE SHOULD BE TOO SHALLOW AND
SUBSIDENCE TOO STRONG TO SUPPORT ANY PRECIPITATION. HIGHS WILL
REMAIN IN THE UPPER 60S WITH LOWS MONDAY NIGHT EVEN MILDER IN THE
MID 50S.
TUESDAY...THERE IS NOW BETTER MODEL AGREEMENT INDICATING THAT THE
UPPER LEVEL PATTERN WILL BE LESS PROGRESSIVE...DELAYING THE
APPROACH OF A COLD FRONT FROM THE WEST. HAVE LOWERED THE POTENTIAL
FOR PRECIPITATION AS A RESULT...ONLY SHOWING A SLIGHT CHANCE OF
SHOWERS FOR INLAND AREAS. TEMPERATURES AHEAD OF THE FRONT SHOULD
WARM WELL INTO THE 70S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HE PATTERN FOR THIS PERIOD CONTINUES TO BE SOMEWHAT UNCERTAIN...
ALTHOUGH THE LATEST TRENDS SUGGEST A DELAYED PROGRESSION OF THE
SYNOPTIC FLOW. MODELS ARE STRUGGLING WITH HOW TO HANDLE THE
EVOLUTION OF THE LARGE UPPER LEVEL TROUGH OVER THE WEST. THE GENERAL
CONSENSUS SEEMS TO BE POINTING TOWARD EJECTING THE TROUGH ENE ON
WEDNESDAY...PUSHING THE FRONT THROUGH SOMETIME WEDNESDAY NIGHT. THE
FORECAST WILL SHOW A CHANCE OF SHOWERS THROUGH WEDNESDAY
NIGHT...WITH DRYING THEN OCCURRING BEHIND THE FRONT AS HIGH PRESSURE
BUILDS IN FOR LATE IN THE WEEK. THE AIRMASS AHEAD OF THE FRONT WILL
REMAIN UNSEASONABLY WARM...WITH COOLER CONDITIONS IN ITS WAKE.
THE GFS IS INDICATING THAT THE UPPER FLOW WILL BE QUITE
PROGRESSIVE...WITH ANOTHER DEEP UPPER TROUGH DEVELOPING OVER THE
WESTERN U.S. BY FRIDAY...THEN PUSHING ANOTHER COLD FRONT THROUGH THE
REGION FRIDAY NIGHT/EARLY SATURDAY. CONFIDENCE IN THIS SOLUTION IS
RATHER LOW GIVEN THE UNCERTAINTY BEFORE THIS PERIOD. HAVE GONE WITH
SLIGHTLY COOLER THAN NORMAL TEMPS FRIDAY NIGHT AND SATURDAY FOR NOW.
THE GFS WAS NOT SHOWING MUCH MOISTURE ASSOCIATED WITH THIS FRONT.
THUS HAVE KEPT POPS BELOW 15 PERCENT.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
EXTREMELY TRICKY AVIATION FORECAST FOR THE NEXT 24 HOURS. OF MOST
IMPORTANCE IS THE NEXT 6-9 HOURS WHERE THE GREATEST AVIATION
IMPACTS CAN BE EXPECTED. SATELLITE SHOWS LOW/MID-LEVEL CLOUD DECKS
RAPIDLY EXPANDING ACROSS THE REGION COINCIDENT WITH INCREASING
ISENTROPIC ASSENT. EXPECT MVFR CIGS TO OVERSPREAD KCHS/KSAV WITHIN
THE NEXT FEW HOURS WITH BOTH RUC AND NAM SOUNDINGS INDICATING A
POTENTIAL FOR IFR CIGS AFTER 09Z...IF NOT SOONER. GIVEN CURRENT
CIG TRENDS SOUTH OF THE ALTAMAHA RIVER...WE SUSPECT KSAV HAS THE
HIGHEST CHANCE FOR SEEING IFR CONDITIONS OVER THE NEXT FEW HOURS
SO WILL INTRODUCE A TEMPO GROUP FROM 09-12Z TO TAKE THIS INTO
ACCOUNT. CONFIDENCE IS NOT AS HIGH AT KCHS SO WILL ONLY UTILIZE A
TEMPO 09-12Z FOR LOW-END MVFR CIGS AT THIS POINT. SHOULD TRENDS
SUGGEST IFR CONDITIONS WILL DEVELOP AND AMENDMENT WILL BE ISSUED.
LOW CONFIDENCE ON EXACTLY WHEN CIGS WILL RISE BACK TO VFR LEVELS
WITH GUIDANCE ESSENTIALLY SPLIT. SOME KEEP CIGS IN MVFR TERRITORY
FOR MUCH OF THE 06Z TAF PERIOD WHILE OTHERS BRING CONDITIONS BACK
TO VFR BY LATE MORNING/EARLY AFTERNOON. WILL TAKE THE MORE
CONSERVATIVE ROUTE AT THIS POINT GIVEN ALL OF THE UNCERTAINTIES
AND SHOW VFR CIGS RETURNING TO BOTH TERMINALS BY 15-16Z.
EXTENDED AVIATION OUTLOOK...THERE IS A POTENTIAL FOR PERIODIC MVFR
CIGS SUNDAY NIGHT INTO TUESDAY IN ASSOCIATION WITH A COASTAL
TROUGH AND INCREASING LOW LEVEL MOISTURE. MVFR OR LOWER VSBYS ARE
ALSO POSSIBLE IN FOG DURING THE LATE NIGHT/EARLY MORNING HOURS
THROUGH THE FIRST PART OF THE WEEK. THERE COULD BE SOME BRIEF
PERIODS OF MVFR CIGS AGAIN WITH SCATTERED SHOWERS ASSOCIATED WITH
THE NEXT FRONT WEDNESDAY AND WEDNESDAY NIGHT.
&&
.MARINE...
BUOY OBSERVATIONS AND WW4 OUTPUT SUGGESTS SEAS HAVE BREACHED 6 FT
ACROSS THE SOUTH CAROLINA MARINE ZONES. HAVE EXPANDED THE SMALL
CRAFT ADVISORY TO THESE ZONES.
A TIGHT SURFACE PRESSURE GRADIENT WILL CONTINUE TO SUPPORT NE
WINDS 15-20 KT INTO THE OVERNIGHT...WITH GUSTS TO 25 KT ACROSS GA
WATERS. PER THE LATEST OPC DEPICTION OF THE WAVE HEIGHT GRADIENT...
CAPPED SEAS AT 5 FT WITH NO SCA/S ACROSS SC NEARSHORE WATERS...BUT
6 FT SEAS WILL IMPACT AREAS AT OR JUST BEYOND THE 20 NM BENCHMARK.
LATER TONIGHT...NAM GUIDANCE CONTINUES TO DEPICT WEAK TROUGH
DEVELOPMENT ACCOMPANIED BY GRADUAL RELAXATION OF THE PRESSURE
GRADIENT. CONFIDENCE IN THIS SCENARIO REMAINS LESS THAN
IDEAL...BUT FORECASTS CONTINUE TO DEPICT DECREASING WINDS LATER
TONIGHT.
HIGH PRESSURE TO THE NORTHEAST OF THE REGION WILL CONTINUE TO
PRODUCE LONG FETCH NE FLOW THROUGH SUNDAY. WINDS WILL VEER TO SE FOR
MONDAY THEN MORE SOUTHERLY BY TUESDAY AS A COLD FRONT GRADUALLY
APPROACHES FROM THE WEST. THERE IS STILL SOME UNCERTAINTY WITH
RESPECT TO THE TIMING/STRENGTH OF THE FRONT...BUT MODEL CONSENSUS
SHOWS IT PUSHING OFFSHORE WEDNESDAY NIGHT. WINDS AHEAD AND
IMMEDIATELY IN WAKE OF THE FRONT COULD APPROACH SMALL CRAFT ADVISORY
LEVELS. MEANWHILE...MARGINAL SMALL CRAFT ADVISORY CONDITIONS DUE TO
SEAS IN THE OUTER GEORGIA WATERS SHOULD CONTINUE THROUGH MID WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ350-
352-354.
SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR AMZ374.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
341 AM CST SUN DEC 4 2011
.DISCUSSION...
340 AM CST
HIGHLIGHTS THIS WEEK WILL INCLUDE RAIN COMING TO AN END...POSSIBLE
SN/RASN/RA ACROSS THE SOUTHEAST MONDAY...LES POTENTIAL FOR
LAKE/COOK LATE SUNDAY NIGHT INTO MONDAY...TRANSITIONING SOUTH TO
LAKE/PORTER INDIANA BY TUESDAY...A FEW DAYS OF QUIET...FOLLOWED
BY A LATE CLIPPER AND SNOW POTENTIAL AND FINALLY A BLAST OF COLD
BY NEXT WEEKEND.
THE EARLY MORNING SURFACE MAP SHOWED THE SURFACE LOW THAT HAS
BEEN BRINGING THE WET AND ACTIVE WEATHER TO THE AREA
TODAY...CONTINUING TO LIFTING NORTH THROUGH CENTRAL WISCONSIN.
MEANWHILE AN ATTENDANT COLD FRONT LAY ROUGHLY ACROSS THE
MISSISSIPPI RIVER...SOUTHWEST NEARLY TO ST LOUIS. THIS FRONT WILL
CONTINUE TO SLOWLY SWEEP FROM WEST TO EAST THIS MORNING EVENTUALLY
PUSHING ITSELF AND THE PRECIP EAST. THE MOST WIDE SPREAD ECHOES HAVE
PUSHED EAST AND ONLY A FEW SCATTERED SHOWERS ARE LOCATED WITH THE
ACTUAL FRONT. ACROSS EAST CENTRAL IOWA...TEMPERATURES HAVE
DROPPED ENOUGH THAT -SN WAS REPORTED...BUT CLOUD TOPS HAVE WARMED
ENOUGH AND ARE WARMER THAN -10C. THIS MEANS THAT THERE IS NO
LONGER ICE INTRODUCTION INTO THE SATURATED LAYERS BELOW...AND A
FEW LOCATIONS REPORTED U.P. AND OR FZDZ. FOR OUR AREA...AFTER THE
FRONT MOVES THROUGH...LOWER LEVEL MOISTURE WILL REMAIN BUT
PROFILES ARE STILL INDICATIVE OF LIQUID PRECIP AND SURFACE TEMPS
WILL REMAIN ABOVE FREEZING.
THE HRRR AND RUC BOTH HAVE A GOOD HANDLE ON THE WESTERN EDGE OF THE
PRECIP AND FRONTAL LOCATION...AND MOST OF IT SHOULD CLEAR THE
ROCKFORD CORRIDOR NEAR SUNRISE...WITH CHICAGO AND EAST JUST A FEW
HOURS BEYOND. WHILE LOWER LEVEL RH WILL REMAIN PREVALENT WITH AND
SHORTLY BEYOND FROPA...MOISTURE ABOVE -10C WILL DISAPPEAR AND
THERE MAY BE SOME LINGERING DZ INTO THE EARLY MORNING HOURS. THE
BIG PUSH OF COLDER AIR ISNT EXPECTED UNTIL LATER THIS EVENING AND
TEMPERATURES WILL REMAIN ABOVE FREEZING...SO NO CONCERN OVER ANY
OTHER PRECIP TYPES THIS MORNING. HIGH TEMPS WILL GENERALLY BE
SEEN EARLY TODAY...AND SLOWLY FALL THROUGH THE DAY. WINDS WILL
ABATE AS HIGH PRESSURE AND A PERIOD OF DRY...SLOWLY MOVE IN.
THE MAIN UPPER LEVEL TROUGHING THAT STRETCHES FROM ROUGHLY
SASKATCHEWAN...SOUTHWEST THROUGH THE FOUR CORNERS REGION WILL NOT
HAVE MUCH REASON TO MOVE UNTIL THE START OF THE WORKWEEK. PRESENT
SHORTWAVE SEEN ON WATER VAPOR IMAGERY ROUNDING THE BASE OF THE
TROUGH...ACROSS SOUTHERN ARIZONA...WILL DAMPEN SOME AS IT
GETS EJECTED ON THE EASTERN FLANK TODAY AND TONIGHT. AS IT DOES
THIS...IT WILL HELP TO AMPLIFY AN INVERTED TROUGH THAT WILL NOSE
ITS WAY TOWARDS THE OHIO VALLEY...EVENTUALLY SPAWNING A WEAK LOW
ACROSS THE TENNESSEE VALLEY. GUIDANCE HAS BEEN HEMMING AND HAWING
WITH JUST HOW FAR NORTH TO BRING THE PRECIP WITH THIS
FEATURE...AND JUST HOW MUCH OF IT WILL REACH INTO THE SOUTHEASTERN
CORNER OF THE CWA. THE LATEST FORECAST TRENDS HAVE BACKED OFF FROM
PREVIOUS...AND DID SCALE BACK ON POPS AS WELL AS COVERAGE. STILL A
LITTLE UNCERTAIN WITH WHERE THE RASN VS STRAIGHT RA LINE WOULD BE
AND WILL MAINTAIN A SORT OF MIX. ALSO OF NOTE FOR COASTAL
LOCATIONS IN THIS SAME TIME FRAME /AS THE INV TROF-LOW SLIDE EAST/
IS THE CHANCE FOR LES. THERMAL PROFILES ACROSS THE SOUTHERN LAKE
WILL BECOME INCREASINGLY UNSTABLE WITH LAKE SURFACE TO H85 DELTA
T`S REACHING THE 12-15C RANGE. EXPECT WEAK SHOWERS TO BEGIN TO
STRETCH FROM LAKE COUNTY IL...EVENTUALLY SOUTH TO COOK AND
GRADUALLY INTO THE MORE TYPICAL LAKE/PORTER IN ORIENTATION. QPF
AMOUNTS NOT LOOKING VERY IMPRESSIVE DURING THE SHORT DURATION AND
WOULD ONLY EXPECT ANYWHERE FROM A TRACE TO MAYBE A TENTH OR TWO OF
ACCUMULATION CLOSE TO THE LAKE TOMORROW AND INTO TOMORROW NIGHT.
THIS WILL ALL BE FOLLOWED BY A FEW DAYS OF QUIET AS ANOTHER RIDGE
OF HIGH PRESSURE SWINGS IN FROM THE NORTHWEST.
A LATE WEEK SYSTEM IS STILL PART OF A LOW CONFIDENCE FORECAST.
GFS HAD BEEN ADVERTISING A WEAK CLIPPER DROPPING FROM THE NORTHERN
PLAINS... AND PREVIOUS EC SOLNS HAD SIMILAR...BUT THE 12Z FLIPPED AND
DEVELOPED A SURFACE LOW THAT LIFTS THROUGH THE MISSISSIPPI
VALLEY...INTO NORTHERN INDIANA...NORTHEAST THROUGH EASTERN
ONTARIO. CONFIDENCE AT THIS POINT ON THAT EURO SOLN IS LOW AND
WILL KEEP THE CHANCE OF SNOW AND NOT BUMP UP (OR DOWN) ANY
CATEGORY UNTIL THE PICTURE IS A LITTLE CLEARER. THE 00Z SOLN BEGAN
TO COME IN AND WAS BACK TO THE ORIGINAL PICTURE WITH THE CLIPPER
RACING THROUGH. DESPITE THE LOWER CONFIDENCE IN THAT FEATURE LATE
THIS WEEK...THE ONE PICTURE OF CLARITY WHAT WILL FOLLOW IT. ALL
LONG RANGE GUIDANCE IS STILL INDICATING THAT THERE WILL BE A LARGE
SURGE OF COLD AIR ENCROACHING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. THERE ARE STILL SOME TIMING DIFFERENCES WITH HOW QUICKLY
THE COLD AIR WILL DUMP IN...WHICH IS DUE IN PART TO THE LARGE
MODEL DIFFERENCES MENTIONED MOMENTS AGO...BUT THE ONE THING THEY
ALL AGREE ON IS HOW COLD THE LOWER LEVELS WILL GET INTO THE
WEEKEND. EVEN A WEEK OUT...THE EC/GFS/GEFS/DGEX/GEM(NHEM THROUGH
F144) ALL HIGHLIGHT H85 TEMPS PLUMMETING TO -16 TO -18
DEGREES...OR EVEN A FEW DEGREES COLDER. TRANSLATE THAT TO THE
SURFACE AND IT WOULD BE POSSIBLE THAT HIGHS WOULD STRUGGLE TO GET
OUT OF THE TEENS FOR MANY LOCATIONS AND OVERNIGHT LOWS LEADING
INTO THE WEEKEND WOULD DIVE BOMB TO THE SINGLE DIGITS /BUT LIKELY A
SMIDGEN WARMER IN THE CHICAGO METRO/. WITH THAT FORECAST STILL
BEING OUT 6-7 DAYS...AND A SLEW OF OTHER WEATHER GOING ON THROUGH
THE EARLY WEEK... WILL ONLY CONTINUE TO TREND DOWN FROM THE
INHERITED LONG RANGE FORECAST. THE BIG SAVING GRACE IS THE LACK OF
SOLID SNOW PACK. IF THAT WERE PRESENT...IT WOULD BE MUCH COLDER.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* LIGHT SHOWERS ENDING
* MVFR CIGS...POSSIBLY DROPPING TO AROUND 1000 FT THIS MORNING.
* STRONG GUSTY SSW WINDS AND POTENTIAL FOR LLWS EARLY...WINDS VEERING
WEST AND DIMINISHING BY MIDDAY.
ALLSOPP
//DISCUSSION...UPDATED 06Z...
SHIELD OF RAIN CONTINUES TO LIFT NORTHEASTWARD ACROSS THE
TERMINALS WITH COVERAGE BECOMING MORE BROKEN JUST TO THE
SOUTHWEST. LOW PRESSURE RESPONSIBLE FOR THE RAIN IS MOVING
NORTHEAST ACROSS EASTERN IOWA AND WILL CROSS NORTHERN LAKE
MICHIGAN SUNDAY MORNING. SOUTH WINDS HAVE INCREASED MARKEDLY AHEAD
OF THE LOW WITH GUSTS CURRENTLY IN THE 25-30 KT RANGE BUT THESE
WILL DIMINISH TO 20-25 KT OVERNIGHT. LOWER CEILINGS NOW MAKING IT
INTO THE TERMINALS WITH LOW END MVFR EXPECTED TO ARRIVE IN THE
NEXT FEW HOURS WHERE IT HAS NOT ALREADY. RFD WILL LIKELY SEE IFR
SOON WITH SOME POTENTIAL FOR PERIODS OF IFR ACROSS THE CHI METRO
TERMINALS WITH A LOWER CHANCE AT GYY. LATEST TRENDS SHOW MVFR VSBY
TO BE RATHER SPOTTY BUT STILL EXPECT IT TO OCCUR TONIGHT THOUGH
CONFIDENCE IS REDUCED IN WHETHER OR NOT IT WILL BE STEADY OR MORE
INTERMITTENT. SHOWERS SHOULD BEGIN TO WANE IN THE 9-12Z TIME
FRAME...POSSIBLY A LITTLE LATER AT GYY. ANOTHER CONCERN IS LOW
LEVEL WIND SHEAR. WINDS INCREASE TO 50-55 KT AT 2000 FT ACROSS THE
AREA...THOUGH SURFACE GUSTS OF 25-30 KT AT THE CURRENT TIME
ARE LIKELY LIMITING THE SHEAR FOR NOW...BUT AS GUSTS DIMINISH A
BIT IN A FEW HOURS SHEAR RISK WILL AGAIN INCREASE.
MVFR CEILINGS WILL CONTINUE THROUGH SUNDAY MORNING WITH IFR
EXPECTED TO IMPROVE TO MVFR AT RFD DURING THE MORNING. SOUTH WINDS
WILL TURN SOUTHWEST THEN WEST THROUGH THE MORNING WITH SOME GUSTS
CONTINUING. EXPECT THAT CEILINGS WILL SLOWLY LIFT...THOUGH REMAIN
MVFR...INTO EARLY AFTERNOON AS THE WEST WINDS USHER IN DRIER LOW
LEVEL AIR. TOUGH TO SAY IF VFR WILL BE REACHED BUT IT WOULD LIKELY
TAKE UNTIL LATE AFTERNOON IF IT DOES...IF NOT EARLY EVENING. WINDS
THEN SHIFT NORTHWEST EARLY SUNDAY EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE IN CIGS DROPPING TO 1000-1500 FT THIS MORNING
THEN INCREASING TO 2000 FT OR BETTER THIS AFTERNOON.
* HIGH CONFIDENCE IN VISIBILITY REMAINING 6 PLUS WITH JUST A FEW
SPRINKLES THROUGH 12Z.
* MEDIUM TO HIGH CONFIDENCE IN WIND FORECAST.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR BUT POTENTIAL FOR IFR/MVFR IN LAKE EFFECT SNOW
SHOWERS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHANCE OF LIGHT SNOW.
MDB
&&
.MARINE...
133 AM CST
A POWERFUL STORM WAS MOVING THROUGH THE GREAT LAKES THIS MORNING.
LOW PRESSURE WILL MOVE QUICKLY FROM WISCONSIN TO NORTHERN LAKE
MICHIGAN THIS MORNING...THEN ON TO QUEBEC BY EVENING. EAST OF THE
TRACK OF THE LOW A VERY STRONG SOUTHERLY LOW LEVEL JET WAS
OCCURRING...WITH 50 KT WINDS JUST 1 TO 2 THOUSAND FEET OFF THE
SURFACE. A STRONG INVERSION WAS LIMITING MIXING BUT GALE FORCE
WINDS WERE WORKING DOWN TO THE LAKE SURFACE OVER THE SOUTH HALF
WITH SOME GALE FORCE GUSTS ON THE EAST SIDE OF THE NORTH HALF OF
THE LAKE. WINDS SHOULD DROP OFF PRETTY QUICKLY AS THE LOW MOVES
RAPIDLY NORTHEAST TODAY AND GALES SHOULD END BY ABOUT NOON.
PRESENTLY GALE WARNING GOES THROUGH MID AFTERNOON BUT IT MAY BE
CANCELED EARLY. WINDS WILL VEER FROM SOUTH TO NORTHWEST THROUGH
THE COURSE OF THE DAY.
TONIGHT THROUGH MONDAY ANOTHER LOW WILL MOVE FROM THE TEXAS COAST
UP THROUGH THE OHIO VALLEY WHILE STRONG HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THIS WILL PRODUCE A PERIOD OF NORTHERLY WINDS
ON LAKE MICHIGAN. THE REST OF THE WEEK HIGH PRESSURE WILL DOMINATE
THE CENTRAL U.S. WHILE LOW PRESSURE BECOMES ANCHORED OVER
NORTHEAST CANADA. THIS WILL PRODUCE A PROLONGED PERIOD OF WESTERLY
WINDS OVER LAKE MICHIGAN FROM MID WEEK INTO THE WEEKEND.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 3 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
313 AM CST SUN DEC 4 2011
.SYNOPSIS...
06Z SFC ANALYSIS HAD A LOW SOUTHEAST OF KVOK AND ANOTHER AROUND
KMXO. THE FRONT RAN BETWEEN THE TWO LOWS AND INTO NORTHERN MISSOURI.
A WEAK TROF RAN FROM THE KMXO LOW TO NEAR KUIN. RADAR TRENDS SHOW
THE STRATIFORM PRECIP HAS EXITED THE AREA WITH A NARROW BAND OF RAIN
ASSOCIATED WITH THE FRONT MOVING INTO ILLINOIS FROM IOWA.
DEFORMATION PRECIPITATION CONTINUES ACROSS IOWA BUT IS DECREASING IN
OVERALL COVERAGE. DEW POINTS AHEAD OF THE FRONT WERE IN THE 40S AND
50S WITH 20S AND 30S BEHIND THE FRONT.
&&
.SHORT TERM...TODAY AND TONIGHT...
THE RUC 285K OMEGA AND 295K CONDENSATION PRESSURE DEFICIT FIELDS
ALONG WITH F VECTOR CONVERGENCE DEPICTS REASONABLY WELL WHAT IS
CURRENTLY GOING ON. THE COLD FRONT WILL BE OVER THE EXTREME EASTERN
CWFA JUST PRIOR TO SUNRISE WITH ITS ASSOCIATED RAIN BAND. THIS RAIN
BAND WILL EXIT THE EASTERN CWFA 13-15Z.
ACROSS THE WESTERN CWFA WET BULB SFC TEMPERATURES ARE DROPPING BELOW
34 DEGREES AND CONDENSATION PRESSURE DEFICITS ARE RISING. WHERE THE
WET BULB SFC TEMPERATURES ARE 32 OR BELOW THE PRECIP CHANGES TO SNOW
WITH SOME PATCHY FZDZ. RUC TRENDS SHOW WET BULB TEMPERATURES
DROPPING THROUGH SUNRISE SO THERE IS A POTENTIAL FOR SOME LIGHT SNOW
AND PATCHY FREEZING DRIZZLE ROUGHLY WEST OF A DUBUQUE TO FAIRFIELD
LINE. HOWEVER...WITH THE DEFORMATION ZONE AND FORCING WEAKENING
ALONG WITH CONDENSATION PRESSURE DEFICITS RISING THE PRECIPITATION
WILL LIKELY BE MORE FLURRIES AND PATCHY FREEZING DRIZZLE. RUC TRENDS
INDICATE THE PRECIPITATION IN THIS AREA WILL END BY MID MORNING.
THUS TO HANDLE THE CURRENT TRENDS...THERE WILL BE A PRE-FIRST PERIOD
TO REFLECT PRECIPITATION TRENDS.
TEMPERATURES WILL CONTINUE TO FALL WITH MINS BEING ACHIEVED AROUND
14Z. BASED ON THE CAA...TEMPERATURES WILL LIKELY CONTINUE FALLING
THROUGH MID MORNING BEFORE STARTING A SLOW RISE. MAX TEMPERATURES IN
THE EASTERN CWFA WILL BE EARLY THIS MORNING WHILE WESTERN AREAS WILL
SEE MAX TEMPERATURES THIS AFTERNOON.
TONIGHT...QUIET AND DRY WX IS EXPECTED WITH A VERY SLOW CLEARING OF
THE CLOUDS.
..08..
.LONG TERM...MONDAY THROUGH SATURDAY
MONDAY THROUGH TUESDAY WE WILL BE ON THE COLD SIDE THAT MOVES
THROUGH THE AREA TODAY AND SHOULD BE DRAPED FROM LOUISIANA NORTHEAST
TO OHIO AND FARTHER NORTHEAST. THE UPPER LEVEL TROUGH WILL STILL BE
WORKING THROUGH THE AREA...AND THE 500MB TROUGH AXIS IS NOT DUE TO
GET PAST THE AREA UNTIL TUESDAY NIGHT. WHILE WE LOSE THE MID AND
UPPER LEVEL MOISTURE...SOME TRAPPED MOISTURE HANGING AROUND 900MB
AND BELOW WILL KEEP THE TIME PERIOD MOSTLY CLOUDY IF NOT CLOUDY
...NOT CLEARING UNTIL TUESDAY AFTERNOON. THE MODELS ARE INDICATING
SOME CLEARING ON MONDAY MORNING...BUT THIS FILLS BACK IN AS NORTH
WINDS ADVECT CLOUDS BACK OVER THE AREA IN THE CYCLONIC FLOW. WILL
HAVE TO WATCH THESE TRENDS...AND WILL TREND PESSIMISTIC FOR NOW AS
IT IS THE TIME OF YEAR FOR GLOOMY CONDITIONS. TEMPERATURES TO BE
MODERATED BY THESE CLOUDS...BUT BELOW NORMAL VALUES CAN BE EXPECTED
WITH THE COLD AIR ADVECTION GOING ON. HIGHS MONDAY IN THE 30S TO
DROP INTO THE MID 20S TO MID 30S FOR TUESDAY. WITH ALL THE LOW
CLOUDS AROUND...WE MAY GET A FEW FLURRIES OR EVEN PATCHY
DRIZZLE...BUT HAVE ONLY PUT IN FLURRIES FOR NOW. TUESDAY NIGHT THE
CLOUDS SHOULD FINALLY CLEAR...HAVE HAVE GONE WITH MUCH COLDER MIN
TEMPS IN THE TEENS AND LOWER 20S.
BY WEDNESDAY THE MAIN UPPER LEVEL TROUGH AXIS SWINGS EAST OF THE
AREA...LEAVING US WITH CYCLONIC NORTHWEST FLOW. ALREADY...A COLD
FRONT IS EXPECTED TO SWING THROUGH ON WEDNESDAY...AND WITH LITTLE
MOISTURE AVAILABLE DO NOT EXPECT ANY PRECIPITATION. A SECOND COLD
FRONT ALONG WITH AN UPPER LEVEL SHORTWAVE IS EXPECTED THROUGH
THURSDAY OR THURSDAY EVENING...AGAIN SOMEWHAT LACKING IN
MOISTURE...BUT IT MAY BE ABLE TO PRODUCE SOME PRECIPITATION THURSDAY
NIGHT ALONG AND BEHIND IT. HOWEVER...THE MODELS HAVE LITTLE IN THE
WAY OF RUN TO RUN CONSISTENCY WITH THIS FEATURE RIGHT NOW...AND HAVE
STAYED FAIRLY CLOSE TO A CONSENSUS FORECAST FOR THIS TIME RANGE.
TEMPERATURES IN THE NORTHWEST FLOW TO BE COLDER THAN NORMAL...WITH
HIGHS ONLY GETTING INTO THE 30S...AND MINS IN THE TEENS AND 20S.
FRIDAY WE WILL BE IN DEEP NORTHWEST FLOW ON THE WEST SIDE OF THE
LONGWAVE TROUGH WITH SOME WEAK RIDGING AT THE SURFACE. BY SATURDAY
THE LONGWAVE TROUGH WILL HAVE SHIFTED FURTHER EAST...AND WARM AIR
ADVECTING BEGINS AGAIN AT MID LEVELS...WITH SOUTHWEST FLOW
DEVELOPING AT THE SURFACE. THESE PERIODS SHOULD BE DRY WITH COLDER
TEMPERATURES AGAIN. ..LE..
&&
.AVIATION... /ISSUED 1142 PM CST SAT DEC 3 2011/
A SURFACE LOW OVER NORTHEAST IOWA WILL CONTINUE TO MOVE NORTHEAST
AWAY FROM THE AREA. EXPECT SOME IFR OR LIFR CIGS/VSBYS FOR A FEW
HOURS EARLY THIS MORNING THEN WITH WEST TO NORTHWEST WINDS
SPREADING OVER THE AREA THE CIGS/VSBYS SHOULD BE IMPROVING TO MVFR BY
12Z TO 15Z. THE RAIN WILL BE TAPERING OFF OVER THE AREA BY 09Z. A
RN/SN MIX IS STILL POSSIBLE AT CID/DBQ BEFORE THE PRECIPITATION
ENDS. FOR THE REST OF THE PERIOD EXPECT MVFR TO LOW END VFR CIGS
SUNDAY AFTERNOON AND EVENING. ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1142 PM CST SAT DEC 3 2011
.AVIATION...
A SURFACE LOW OVER NORTHEAST IOWA WILL CONTINUE TO MOVE NORTHEAST
AWAY FROM THE AREA. EXPECT SOME IFR OR LIFR CIGS/VSBYS FOR A FEW
HOURS EARLY THIS MORNING THEN WITH WEST TO NORTHWEST WINDS
SPREADING OVER THE AREA THE CIGS/VSBYS SHOULD BE IMPROVING TO MVFR BY
12Z TO 15Z. THE RAIN WILL BE TAPERING OFF OVER THE AREA BY 09Z. A
RN/SN MIX IS STILL POSSIBLE AT CID/DBQ BEFORE THE PRECIPITATION
ENDS. FOR THE REST OF THE PERIOD EXPECT MVFR TO LOW END VFR CIGS
SUNDAY AFTERNOON AND EVENING. ..DLF..
&&
.PREV DISCUSSION... /ISSUED 308 PM CST SAT DEC 3 2011/
SYNOPSIS...
MAIN FEATURE OF INTEREST IS THE UPPER LEVEL LOW OVER LAS VEGAS WITH
A LEAD WAVE EJECTING OVER WESTERN KANSAS AT 18Z. MEANWHILE...
SURFACE LOW IS LOCATED IN SOUTH-CENTRAL KANSAS WITH THE COLD FRONT
EXTENDING NORTH TO FORT DODGE /KFOD/ AND THE UPPER PENINSULA. TEMPS
BEHIND THE FRONT DIVE FROM THE MID AND SOME UPPER 40S INTO THE LOWER
30S. LARGE AREA OF RAIN IN THE WARM SECTOR LIFTED NORTH TODAY WITH
PRECIP AMOUNTS TYPICALLY IN THE ONE HALF TO ONE INCH RANGE. NEXT
ROUND OF PRECIP ASSOCIATED WITH THE MAIN COLD FRONT NOW SPANNING
CENTRAL IOWA AND MUCH OF MISSOURI.
SHORT TERM...TONIGHT AND SUNDAY...
MAIN FORECAST CONCERN TONIGHT IS THE BEHAVIOR OF THE NEXT ROUND OF
PRECIP. RUC BRINGS THE SURFACE LOW OVER VINTON /KVTI/ BY 03Z THIS
EVENING. THIS IS SLIGHTLY FASTER AND FARTHER NORTHWEST THAN MODEL
FORECASTS HAD BEEN BUT IS IN LINE WITH THE OVERALL TREND TO A WARMER
FORECAST. IN TERMS OF PRECIP...THIS MORE WESTERN TRACK...AS SEEN IN
THE RUC AND CURRENT RADAR TRENDS...SUGGESTS RAIN THROUGH THE EVENING
WITH ONLY A BRIEF CHANGE TO SNOW IN THE FAR NORTHERN COUNTIES BEFORE
PRECIP ENDS LATE TONIGHT/EARLY SUNDAY MORNING. MUCH OF THE AREA TO
BE DRY-SLOTTED OVERNIGHT WITH ONLY THE NORTHERN AND WESTERN SECTIONS
EXPECTED TO SEE WRAP-AROUND PRECIP AS THE LOW RACES OFF TO THE
NORTHEAST. EVEN SO...BUFKIT SOUNDINGS FOR KCID AND KDBQ LIMIT ANY
FROZEN PRECIP TO ONLY AN HOUR OR TWO BEFORE ENDING ALTOGETHER. THUS
HAVE REDUCED SNOW AMOUNTS AND ENDED PRECIP A FEW HOURS EARLIER THAN
PREVIOUS FORECAST. ..DMD..
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY
HIGH PRESSURE AT THE SURFACE MIGRATING THROUGH THE NORTHERN PLAINS
INTO THE UPPER MS VALLEY TO BRING NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES FROM SUNDAY NIGHT THROUGH WEDNESDAY. THROUGH THIS
PERIOD...MODELS IN GENERAL AGREEMENT FEATURING AN UPPER LEVEL
POSITIVE TILT LONG WAVE TROUGH TRANSITIONING EAST THROUGH THE CENTRAL
U.S....SUPPRESSING THE MAIN BAROCLINIC AXIS AND STORM TRACK WELL TO
THE SOUTHEAST. A WAVE OF LOW PRESSURE TRACKING ALONG THE OHIO RIVER
MONDAY WILL SPREAD SNOW INTO PORTIONS OF MO AND IL...AND WILL KEEP
ONLY SLIGHT CHANCE POPS CONFINED TO THE FAR EAST AND SOUTH MONDAY
NIGHT ON THE EXTREME NW EDGE OF THIS SYSTEM. OTHERWISE...NO
PRECIPITATION IS EXPECTED...BUT HIGH LEVEL LIFT AND MOISTURE ALOFT
AHEAD OF THE UPPER TROUGH AXIS WILL FAVOR MOSTLY CLOUDY SKIES FOR
MUCH OF MON THROUGH WED.
THU THROUGH SAT...MODEL CONSENSUS INDICATES A COLD FRONT DROPPING
SOUTH THROUGH THE REGION LATE THURSDAY...FOLLOWED BY MUCH COLDER
TEMPERATURES FRIDAY AND SATURDAY FOLLOWING A FRESH INFLUX OF COLD
AIR AT 850 MB THAT HAS BEEN BUILDING WELL TO THE NORTH. THERE
CONTINUES TO BE CONSIDERABLE DIFFERENCES WITH THE TIMING AND
PLACEMENT OF CRITICAL UPPER LEVEL TROUGHS AND SURFACE FEATURES IN
THIS TIME FRAME...THUS THE POTENTIAL FOR PRECIPITATION REMAINS LOW
CONFIDENCE. THE CURRENT SUITE OF MODELS USED IN THE EXTENDED
SUPPORTS OUR SLIGHT TO LOW END CHANCES FOR LIGHT SNOW FOR THU NIGHT
FOLLOWING THE PASSAGE OF THE COLD FRONT. AHEAD OF THIS FRONT...HIGHS
THURSDAY SHOULD REACH INTO THE 30S IN MOST AREAS. THIS IS FOLLOWED
BY 20S FRIDAY AND SATURDAY WITH OVERNIGHT LOWS IN THE SINGLE DIGITS
AND TEENS. ..SHEETS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1211 AM CST SUN DEC 4 2011
.UPDATE...
UPDATED FOR THE 06Z AVIATION DISCUSSION BELOW.
.DISCUSSION...
SNOW HAS BEGUN TO SPREAD INTO S MN AND WILL CONTINUE TO EXPAND NE
RAPIDLY DURING THE REMAINDER OF THE AFTERNOON. A BIT OF SATURATION
LEFT TO DO IN LOWER LEVELS BUT CIGS ARE BEGINNING TO LOWER ACROSS
S MN. IR SATELLITE SHOWS ELONGATED VORT FROM W KS INTO SC NEB
LIFTING NE. GFS/NAM SIMILAR ON TIMING BRINGING MAIN VORT INTO SC MN
BY 00Z AND THEN LIFTING INTO CENTRAL WI BY 06Z. GFS HAS INCREASED
QPF VALUES A BIT MORE TOWARD THE NAM SOLUTION. INCREASED SNOW
AMOUNTS A BIT ACROSS AREAS FROM MKT TO SE METRO BASED LARGELY ON
TRACK OF SURFACE/850 MB LOW CENTERS. HEAVY SNOW OFTEN SETS UP 70
TO 90 MILES N OF 850 MB LOW TRACK..AND 850 MB LOW TRACKS FROM SW
IA TO JUST S OF LSE BY 06Z THEN INTO E UPR MICHIGAN BY 12Z. KEPT
SNOW AMOUNTS IN THE 3 TO 6 INCH ADVISORY. FAVORABLE ISENTROPIC
LIFT COMES THRU RATHER QUICKLY WITH 3-3.5G/KG SO HESITATE TO GO
ANY HIGHER. WILL BE A PERIOD FROM AROUND 22Z TO 05Z WHERE ADVISORY
AREA WILL BE UNDER STRONG UPPER DIVERGENGE FROM COUPLED UPPER JET...
FAVORABLE DENDRITIC TEMPERATURES AND STRONG 600 MB FULL WIND
FRONTOGENSIS WHICH COULD BRING A PERIOD OF A FEW HOURS OF
VISIBILITY INTO THE 1/2 SM RANGE AS FAR N AS MSP. LIKE THE TIMING
OF THE RUC BUFKIT SNOW ACCUMS IN THAT WINDOW. DECREASED SNOW
AMOUNTS SLIGHTLY IN W SIDE OF ADVY AREA AROUND SPRINGFIELD AND
GAYLORD. ADVISORY WILL LIKELY BE ABLE TO BE EXPIRED BY 06Z ACROSS
MUCH OF THE MN CWA WITH NO SIGNIFICANT WIND EXPECTED IN WAKE OF
SNOW.
COOLER FOR SUNDAY...BUT TROF DROPPING OUT OF CANADA WILL BACK
WINDS ENUF TO KEEP MAIN PUSH OF COLD AIR NORTH OF AREA. AS THIS
SYSTEM MOVES THRU COLD AIR WILL MOVE IN FOR MONDAY WITH HIGHS ONLY
IN THE TEEN TO MID 20S. SLIGHT MODERATION FOR WEDNESDAY AS WEAK
TROF MOVES ACROSS AREA. AFTER THAT AREA REMAINS IN COLD AND DRY
NW FLOW AT LEAST UNTIL NEXT WEEKEND.
WITH SNOW COVER EXPECTED TONIGHT ACROSS S MN INTO WC WI WILL BE SOME
SOME MORNINGS WHERE WE SHOULD GET MIN TEMPS DOWN NEAR
ZERO...TUESDAY AND PROBABLY AGAIN FRIDAY/SATURDAY.
.AVIATION.../06Z TAF ISSUANCE/
HAVE THE SNOW CLEARING EAST CENTRAL MN BY ROUGHLY 09Z PER THE
SHARP CLEARING EDGE TO THE BACK OF THE RADAR NOW. LIKELY LOSE IFR
VISIBILITY BY AROUND 08Z IN MN DUE TO THE DECREASING SNOW RATES.
KEAU MAY STILL SEE CONDITIONS GET POORER FOR A COUPLE HOUR WINDOW
THIS MORNING BEFORE IMPROVING CLOSER TO SUNRISE. IN TERMS OF
CLOUDS...THE CONDITIONAL CEILINGS WHEN SNOW IS FALLING COULD
CREATE SHORT PERIODS OF IFR CEILINGS OVER THE NEXT FEW HOURS...BUT
OVERALL WE ARE MAINLY STUCK WITH A MVFR DECK. THIS MIGHT BE WITH
US FOR SOME TIME. DOING A SIMPLE EXTRAPOLATION OF THE BACK EDGE OF
THE STRATUS GETS CLEARING INTO WESTERN MN BY AROUND 12Z.
HOWEVER...GIVEN THE TIME OF YEAR AND DUE TO THE FACT WE REALLY
DON`T SEE MUCH OF A PATTERN CHANCE UNTIL MONDAY...TRENDED
PESSIMISTIC WITH THE MVFR CEILINGS.
KMSP...VISIBILITY HAS IMPROVED OVER THE LAST HOUR AT THE AIRPORT
AND SHOULD SEE THE SNOW TAPER TO NOTHING BY AROUND 09Z. THE
CEILINGS HAVE TEMPORARILY JUMPED UP TO 3500FT...BUT WITH LOWER
CEILINGS TO THE WEST...IT SHOULD ONLY BE A MATTER OF TIME BEFORE
MVFR STRATUS MOVES BACK IN AND LINGERS FOR MOST OF THE DAY.
HOWEVER...FAIRLY CONFIDENT WE`LL REMAIN ABOVE 2000FT MUCH OF THE
TAF PERIOD. WIND DIRECTION WILL REMAIN OUT OF THE NORTHWEST AND
GRADUALLY DECREASE AFTER SUNRISE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR ANOKA-BLUE
EARTH-BROWN-CARVER-CHISAGO-DAKOTA-FARIBAULT-FREEBORN-
GOODHUE-HENNEPIN-LE SUEUR-MARTIN-NICOLLET-RAMSEY-RICE-SCOTT-
SIBLEY-STEELE-WASECA-WASHINGTON-WATONWAN.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
BAP/CLF
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
311 AM CST SUN DEC 4 2011
.DISCUSSION...
LIGHT SNOW WHICH AFFECTED PORTIONS OF OUR AREA ON SATURDAY HAS
PUSHED INTO CENTRAL MINNESOTA AND CENTRAL IOWA VERY EARLY THIS
MORNING. BEHIND THE EXITING SYSTEM...A BROAD AREA OF STRATUS HAS
DEVELOPED ACROSS THE EASTERN DAKOTAS INTO EASTERN NEBRASKA...THOUGH
MODELS NOT PICKING UP ON THIS AT ALL. 06Z RUC 925 MB RH TIME SECTION
HINTING AT IT...AND HAS IT PULLING EASTWARD THROUGH THE
MORNING...EXITING OVER OUR FAR EAST BY 18Z. OTHERWISE...A RELATIVELY
QUIET DAY IN STORE...WITH CLOUDS INCREASING IN OUR WEST IN THE
AFTERNOON AS A WEAK SHORTWAVE DROPS SOUTHWARD ON A NORTHWESTERLY
UPPER LEVEL FLOW. NOT MUCH IN THE WAY OF DYNAMICS WITH THIS
FEATURE...BUT COULD SPIT OUT SOME VERY LIGHT SNOW IN OUR WEST BY
LATE THIS AFTERNOON INTO TONIGHT. TEMPERATURES A BIT TRICKY
TODAY IN BETWEEN CLOUD COVER...THOUGH WHAT IS MORE CERTAIN IS THAT
READINGS WILL NOT WARM A WHOLE LOT OVER SNOW COVERED AREAS...WITH
HIGHS GENERALLY IN THE MID 20S THROUGH NORTHWESTERN IOWA AND
PORTIONS OF SOUTHWESTERN MINNESOTA. TO THE WEST...WITH MORE SUN AND
BETTER MIXING IN A TRANSITIONING SOUTHWESTERLY LOW LEVEL
FLOW...HIGHS WILL REACH THE MID 30S ACROSS THE MUCH OF THE JAMES
RIVER VALLEY INTO SOUTH CENTRAL SOUTH DAKOTA.
WINDS WILL BECOME NORTHWESTERLY AND PICK UP FROM WEST TO EAST
TONIGHT IN A TIGHTENING GRADIENT AND COLD AIR ADVECTION BEHIND THE
EXITING SHORTWAVE AND SURFACE LOW/ASSOCIATED FRONTAL BOUNDARY. THE
WINDS AND CLOUD COVER WILL KEEP OVERNIGHT LOWS SOMEWHAT IN
CHECK...THOUGH WILL STILL DROP INTO THE TEENS...EXCEPT SINGLE DIGITS
OVER SNOW COVER.
COLDER AIR WILL CONTINUE TO FILTER INTO THE REGION ON MONDAY WITH A
SURFACE HIGH BUILDING INTO THE REGION. TEMPERATURES WILL NOT RISE
MUCH FROM EARLY MORNING LOWS...WITH HIGHS ONLY IN THE UPPER TEENS TO
LOWER 20S. SOUTHERLY FLOW RETURNS TO THE REGION ON TUESDAY BEHIND
THE EXITING HIGH...AND TEMPERATURES TRY TO WARM A BIT IN THE
WEST...INTO THE MID AND UPPER 20S...WHILE READINGS OVER SNOW COVERED
AREAS MAY ACTUALLY BE A LITTLE COOLER THAN MONDAYS HIGHS WITH LESS
MIXING...REMAINING ONLY IN THE UPPER TEENS.
EVEN WARMER ON WEDNESDAY AHEAD OF THE NEXT ARCTIC SURGE WHICH WILL
DIVE SOUTHWARD ON WEDNESDAY NIGHT AND THURSDAY. COULD GET A LITTLE
SNOW ALONG THE LEADING EDGE OF THIS SURGE/FRONTAL GRADIENT DURING
THAT TIME FRAME...THOUGH ANY SNOW SHOULD BE LIGHT. HIGHS ON
WEDNESDAY WILL BE IN THE UPPER 20S TO MID 30S...THEN DROP BACK TO
THE LOWER TO MID 20S ON THURSDAY. FRIDAY LOOKS TO BE THE COLDEST DAY
OF THE WEEK...WITH HIGHS MID TEENS TO AROUND 20...FOLLOWED BY SOME
WARMING ON SATURDAY. LOOKS TO REMAIN DRY BOTH DAYS.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
DRIER AIR MASS SETTLING INTO THE AREA TONIGHT. SNOW BAND LINGERING
IN THE EXTREME SOUTHEAST CORNER OF THE CWA SHOULD EXIT THE AREA
WITHIN THE NEXT HOUR OR SO. LATEST SATELLITE IMAGERY SHOWS
RELATIVELY FAST MOVING AND NARROW TONGUE OF LOW STRATUS TRACKING
SOUTHEAST ACROSS EASTERN NORTH DAKOTA AND INTO NORTHEAST AND SOUTH
CENTRAL SOUTH DAKOTA. MVFR CEILINGS AROUND 2500 TO 3000 FEET WILL BE
ASSOCIATED WITH THIS BAND WHICH WILL TRACK ACROSS THE ENTIRE CWA
INTO THE EARLY MORNING HOURS. DESPITE A FRESH SNOWPACK ACROSS THE
SOUTHEASTERN HALF...RELATIVELY LIGHT WINDS AND LATE CLEARING
TONIGHT...THINK THAT THE AIRMASS WILL BE TOO DRY TO SUPPORT FOG
ALTHOUGH IT WILL BE SOMETHING TO CONTINUE TO MONITOR. VFR CONDITIONS
AND RELATIVELY LIGHT WINDS ON TAP FOR SUNDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1149 PM CST SAT DEC 3 2011
.AVIATION...
A WIDESPREAD AREA OF SHRA WITH EMBEDDED TSRA HAS DEVELOPED ACROSS
CENTRAL TEXAS. ADDITIONAL DEVELOPMENT IS EXPECTED THROUGH THE
OVERNIGHT HOURS AS THIS SYSTEM PROGRESSES SOUTHWARD AHEAD OF AN
APPROACHING COLD FRONT WITH THE POTENTIAL FOR PERIODS OF -SHRA AND
TEMPO -TSRA. A PRE-FRONTAL TROUGH AHEAD OF THE COLD FRONT WILL
ENABLE SFC WINDS TO GRADUALLY BACK FROM SE TO E THROUGH THE NEXT
FEW HOURS BEFORE THE FRONT ARRIVES BETWEEN 09-12Z ACROSS THE
REGION. MVFR CIGS STRETCH FROM KJCT TO KBMQ TO KTPL AND ARE
EXPECTED TO REACH THE SOUTH CENTRAL TEXAS TAF SITES BY 07Z. CIGS
WILL DETERIORATE TO IFR AND POTENTIALLY LIFR THROUGH THE OVERNIGHT
HOURS. ADDITIONALLY...AHEAD OF THE FRONT...A MIX OF -DZ/BR/-SHRA
WILL LOWER VSBYS TO MVFR/IFR PARTICULARLY AT KAUS/KSAT/KSSF. THE
COLD FRONT WILL ARRIVE SUNDAY MORNING...BUT IMPROVEMENTS TO CIGS
AND VSBYS WILL BE SLOW WITH VFR CONDITIONS STILL NOT EXPECTED TO
RETURN DURING THE 24-HR NOR 30-HR TAF PERIODS.
&&
.PREV DISCUSSION... /ISSUED 933 PM CST SAT DEC 3 2011/
UPDATE...
PRE-FRONTAL TROUGH EXTENDS FROM WACO TO LAMPASAS TO JUNCTION TO
DRYDEN WHILE CANADIAN COLD FRONT EXTENDS FROM WICHITA FALLS TO
ABILENE TO MIDLAND. TROUGH AND FRONT HAVE SPEED UP SLIGHTLY AND
NEW 00Z NAM AND RUC BRING THESE FEATURES THROUGH SOUTH CENTRAL
TEXAS A LITTLE EARLIER THAN PREVIOUSLY FORECAST WHICH SEEMS
REASONABLE. MAIN IMPACTS ARE TO GO WITH COOLER TEMPERATURES AND
EARLIER WIND SHIFTS TO NORTHERLY ON SUNDAY...ESPECIALLY DURING THE
LATE MORNING AND AFTERNOON ALONG WITH LOWER POST-FRONTAL DEWPOINTS
FOR SUNDAY THROUGH MONDAY. REMAINDER OF YOUR SOUTH CENTRAL TEXAS
FORECAST IS ON TRACK.
PREV DISCUSSION... /ISSUED 538 PM CST SAT DEC 3 2011/
AVIATION...
A BRIEF WINDOW OF VFR CONDITIONS WILL CONTINUE THROUGH THE NEXT
FEW HOURS BEFORE THE ONSET OF MVFR CIGS BY ABOUT 03Z. STREAMER
SHOWERS WILL CONTINUE TO DEVELOP MAINLY EAST OF A LINE FROM KERV
TO KHDO TO KCOT THROUGH THE EVENING HOURS AS WARM AIR ADVECTION
PERSISTS IN ADVANCE OF AN APPROACHING COLD FRONT. THE DEEP
MOISTURE IN THE LOWER LEVELS WILL PROMOTE THE DETERIORATION OF
CIGS TO IFR AND POTENTIALLY LIFR CONDITIONS OVERNIGHT. AHEAD OF THE
FRONT...A MIX OF -DZ/BR/-SHRA IS EXPECTED TO LOWER VSBYS TO MVFR/IFR
PARTICULARLY AT KAUS/KSAT/KSSF. THE COLD FRONT WILL ARRIVE SUNDAY
MORNING...BUT IMPROVEMENTS TO CIGS AND VSBYS WILL BE SLOW WITH VFR
CONDITIONS NOT EXPECTED TO RETURN DURING THE 24-HR NOR 30-HR TAF
PERIODS.
PREV DISCUSSION... /ISSUED 314 PM CST SAT DEC 3 2011/
DISCUSSION...
PRE-FRONTAL TROUGH/DRY LINE HAS PUSHED INTO THE FAR WESTERN CWA
THIS AFTERNOON WITH GOOD MIXING/CLEARING ACROSS THE WESTERN COUNTIES.
THE SKIES OVER THE EASTERN COUNTIES GENERALLY ALONG AND EAST OF
I35 HAVE REMAINED MOSTLY CLOUDY WITH PATCHY LIGHT RAIN AND DRIZZLE
CONTINUING IN THE DEEP SLY GULF FLOW. RAIN CHANCES WILL INCREASE
AGAIN LATER THIS EVENING INTO THE OVERNIGHT HOURS AND SUNDAY.
COMBINATION OF UPPER AIR DISTURBANCES IN THE SWLY FLOW
ALOFT...CONVERGENCE ALONG THE PRE-FRONTAL SURFACE TROF...AND THE
INCREASING LOW LEVEL GULF FLOW WILL RESULT IN GOOD CHANCES FOR
DEEP CONVECTION. BECAUSE OF THE DEEP GULF INFLOW AHEAD OF THE
TROUGH...WILL SEE GENEROUS QPF VALUES ESPECIALLY ACROSS THE NE/ERN
COUNTIES. RAINFALL AMOUNTS OF ONE HALF TO ONE INCH OVER THE NEXT
24 HOURS WITH ISOLATED STORM TOTALS OF NEAR 2 INCHES POSSIBLE.
THE COLD FRONT WAS PUSHING THROUGH THE TX PANHANDLE THIS AFTERNOON
AND MODELS HAVE SLOWED THE PROGRESSION THRU S TX ON DURING THE
DAY ON SUNDAY. CURRENT THINKING IS A FRONTAL PASSAGE INTO THE NRN
HILL COUNTRY/EDWARDS PLATEAU BY 6 AM AND TO NEAR I10/HIGHWAY 90 BY
AROUND NOON...AND THRU THE REMAINDER OF THE CWA BY 5 PM. HIGH
TEMPERATURES WILL OCCUR JUST AHEAD OF THE COLD FRONT AND
TEMPS ACROSS THE SRN CWA COULD REACH THE MID OR UPPER 70S. WILL
SEE SLOWLY FALLING TEMPERATURES BEHIND THE FRONT AS COLD AIR
ADVECTION WILL BEHIND TO INCREASE LATE SUNDAY NIGHT INTO MONDAY.
MONDAY WILL BE THE MORE BONE CHILLING DAY WITH THE COMBINATION OF
COLD...WIND AND POST FRONTAL OVERRUNNING LIGHT RAIN.
WINTER PRECIPITATION FOR THE FAR NRN COUNTIES APPEARS UNLIKELY GIVEN
THE WARMER 12Z SOUNDING TEMP PROFILE FOR MONDAY NIGHT/TUESDAY
MORNING...AND MOST PRECIPITATION WILL BE ENDING FROM THE WEST BY
SUNRISE TUESDAY MORNING. GRADUAL CLEARING TUESDAY WITH ALLOW FOR
A COUPLE OF NIGHTS OF FREEZING TEMPERATURES AREA WIDE TUESDAY
NIGHT AND WEDNESDAY NIGHT. STRONG WESTERLY FLOW ALOFT WILL RESULT
IN A QUICK RETURN OF MOISTURE AND OVERRUNNING SETTING UP FOR LATE
THURSDAY INTO FRIDAY AHEAD OF THE NEXT COLD FRONT. ANOTHER FAIRLY
GOOD SHOT OF COLD CANADIAN AIR WILL ARRIVE FRIDAY NIGHT INTO
SATURDAY...HOWEVER IT DOES NOT APPEAR THERE WILL BE ANY POST
FRONTAL PRECIPITATION AS A DRY WNWLY FLOW DEVELOP BEHIND A SHORT
WAVE AS THE COLD AIR ADVECTION BEGINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 54 58 44 49 36 / 80 80 90 60 20
AUSTIN BERGSTROM INTL AIRPORT 57 59 43 50 34 / 80 80 90 60 30
NEW BRAUNFELS MUNI AIRPORT 62 63 44 50 35 / 70 70 80 50 20
BURNET MUNI AIRPORT 47 49 40 47 35 / 80 80 90 50 20
DEL RIO INTL AIRPORT 55 56 45 52 36 / 50 30 50 20 10
GEORGETOWN MUNI AIRPORT 52 55 40 47 34 / 80 80 90 60 20
HONDO MUNI AIRPORT 63 63 45 53 35 / 70 50 80 30 20
SAN MARCOS MUNI AIRPORT 61 63 45 48 36 / 70 70 90 50 30
LA GRANGE - FAYETTE REGIONAL 64 67 48 50 38 / 70 80 90 70 30
SAN ANTONIO INTL AIRPORT 62 63 46 53 37 / 70 60 80 40 20
STINSON MUNI AIRPORT 64 64 47 52 38 / 70 60 80 40 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...25
SYNOPTIC/GRIDS...04
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1130 PM CST SAT DEC 3 2011
.AVIATION...
SOME SLIGHTLY DRIER AIR IN THE LOW LEVELS HAS MOVED INTO THE
REGION BEHIND THE INITIAL WIND SHIFT/WEAK FRONT. THIS HAS ALLOWED
CIGS TO GO VFR EVERYWHERE BUT WACO. WITH MORE RAIN ON THE WAY
OVERNIGHT EXPECT LOW LEVEL SATURATION TO OCCUR AND HELP BRING BACK
MVFR CIGS AROUND SUNRISE...WITH IFR CIGS BY TOMORROW AFTERNOON.
LIGHT RAIN WILL BE ALMOST CONTINUOUS THROUGH THE NEXT 24 HOURS BUT
AGAIN WILL NEED LOW LEVEL SATURATION BEFORE VIS GETS AFFECTED. A
COUPLE STORMS HAVE FORMED SW OF DFW TRACON AND WILL SHOW VCTS
THROUGH 9Z THIS MORNING AS THESE CELLS MOVE THROUGH. AFTER THAT
ANY THUNDER SHOULD BE VERY ISOLATED AND WILL KEEP WEATHER TYPE AS
SHRA. GENERALLY IFR CIGS AND MVFR VIS EXPECTED SUNDAY AFTERNOON
THROUGH MONDAY MORNING.
WINTER POTENTIAL FOR DFW TRACON CONTINUES TO LOOK LOW WITH
SUBFREEZING TEMPS NOT EXPECTED SUNDAY NIGHT OR MONDAY WHEN PRECIP
IS OCCURRING. RAIN/SNOW LINE EARLY MONDAY MORNING SHOULD STAY
JUST NW OF DFW TRACON.
TR.92
&&
.UPDATE...
PRECIP CONTINUES TO EXPAND IN AREAL COVERAGE OVER THE NORTHEAST
QUADRANT OF THE CWA. LATEST RUC ANALYSIS SHOWS THE STRONG LIFT
RESPONSIBLE FOR THE PRECIP ON THE 295K ISENTROPIC SURFACE. 35
KNOT SOUTHERLY WINDS ARE QUICKLY LIFTING MOIST PARCELS FROM 975
MB TO 875 MB AS THE COLDER AIR MASS MOVES EAST. UPPED POPS IN THE
0-6Z TIMEFRAME TO 100 PERCENT FOR AREAS EAST AND NORTH OF A
SHERMAN TO DALLAS TO CANTON LINE GIVEN THE EXPECTED INTENSITY OF
THIS LIFT AND CURRENT RADAR TRENDS. THE RUC SHIFTS THE BEST LIFT
ASSOCIATED WITH THE COLD AIR WEDGE TO THE SOUTH LATER TONIGHT AND
WILL HAVE 80 POPS FOR THE SOUTHERN ZONES AFTER 6Z.
WIDESPREAD PRECIP IS EXPECTED TOMORROW BEHIND THE FRONTAL BOUNDARY
AS WARM/MOIST AIR IS LIFTED OVER THE COLD AIR. BUMPED UP POPS TO
100 PERCENT FOR MOST OF THE CWA EXCEPT FOR THE NORTHWESTERN ZONES
FOR THE SUNDAY PERIOD.
85/NH
&&
.PREV DISCUSSION... /ISSUED 321 PM CST SAT DEC 3 2011/
SHORTWAVE DISTURBANCE CONTINUES TO LIFT UP THROUGH THE SOUTHERN
PLAINS THIS AFTERNOON RESULTING IN THE SLOW EASTWARD PROGRESSION OF
A BAND OF LIGHT TO MODERATE RAIN CURRENTLY ALONG A LINE FROM
COMANCHE TO WEATHERFORD TO GAINESVILLE. LOW RAINFALL AMOUNTS FOR
MOST AREAS...BUT SOME ISOLATED AMOUNTS TO BETWEEN A QUARTER AND HALF
INCH WILL BE POSSIBLE AS THIS BAND MOVES ACROSS NORTH TEXAS. THE
RAIN-COOLED AIR HAS RESULTED IN THE OLD FRONT SAGGING TO A
GAINESVILLE TO DECATUR TO CISCO LINE THIS AFTERNOON WITH
TEMPERATURES IN THE 50S BEHIND THE FRONT WHILE REMAINING IN THE 60S
TO LOWER 70S AHEAD OF IT. A FEW EMBEDDED THUNDERSTORMS ARE
POSSIBLE...BUT NOT LIKELY THROUGH THIS EVENING.
A STRONGER COLD FRONT CAN BE SEEN NOW MOVING THROUGH THE HIGH PLAINS
OF EASTERN CO/WESTERN KS THIS AFTERNOON. THE FRONT SHOULD ARRIVE
INTO OUR FAR NORTHWEST COUNTIES BY MIDNIGHT...THEN QUICKLY PUSH TO
AN ATHENS...WACO...LAMPASAS LINE BY SUNRISE SUNDAY. THE FRONT WILL
CLEAR THE REMAINDER OF NORTH TEXAS BY LATE MORNING SUNDAY. THE
STRONG COLD FRONT WILL OVERTAKE OUR CURRENT FRONT WITH THE BULK OF
MODERATE RAIN AND ISOLATED THUNDERSTORMS OCCURRING AHEAD OF THE
FRONT. SOME LIGHT RAIN WILL LIKELY REMAIN BEHIND THE FRONT. HIGHS
SUNDAY WILL OCCUR BETWEEN MIDNIGHT AND MIDDAY SUNDAY...WITH FALLING
AFTERNOON TEMPERATURES AND GUSTY NORTH WINDS 15 TO 20 MPH AFTER
FROPA. THE GUSTY WINDS AND LIGHT RAIN WILL MAKE FOR A RAW AND WET
DAY ACROSS NORTH TEXAS...THOUGH OVERALL HEAVIER RAINFALL SHOULD
SHIFT TO THE SOUTH AND EAST OF OUR AREA LATE SUNDAY AFTERNOON AND
EVENING.
A MORE ROBUST SHORTWAVE DISTURBANCE ARRIVES LATE SUNDAY NIGHT INTO
MONDAY AND WILL INDUCE ISENTROPIC ASCENT ONCE AGAIN WITH A COLD AND
AT TIMES MODERATE RAIN ACROSS NORTH TEXAS. TEMPERATURES WILL LIKELY
FALL INTO THE MID 30S BY DAYBREAK MONDAY MORNING ACROSS AREAS TO THE
NORTHWEST OF THE DFW METROPLEX. MOST MODELS...INCLUDING SREF AND WRF
...ARE HOLDING THE DEEPER COLD AIR OFF TO THE NORTHWEST OF THIS AREA
THROUGH MIDDAY MONDAY. DESPITE TEMPERATURES JUST ABOVE FREEZING...A
RAIN/SNOW MIX COULD OCCUR ACROSS THIS AREA MONDAY MORNING AS THERMAL
PROFILES COOL QUICKLY TO OR JUST BELOW FREEZING. COLD RAIN IS
EXPECTED ELSEWHERE.
REGARDING THE WINTER WEATHER POTENTIAL...AS THE SHORTWAVE MOVES
QUICKLY ACROSS THE AREA...DRYING ABOVE THE BOUNDARY LAYER WILL
FOLLOW IN ITS WAKE. AS A RESULT OF THIS DRYING...ICE CRYSTAL
PRODUCTION WILL BE LIMITED AND A MIXTURE OF VERY LIGHT RAIN/
DRIZZLE/FLURRIES IS LIKELY. ISENTROPIC DOWNSLOPE CONTINUES DURING
THE OVERNIGHT HOURS INTO TUESDAY MORNING WITH CLOUDS GRADUALLY
DECREASING.
NORTH TEXAS WILL REMAIN UNDER THE INFLUENCE OF CYCLONIC FLOW ALOFT
THROUGH THE WEEK...RESULTING IN PARTLY CLOUDY SKIES AND COLD
CONDITIONS. THE STUBBORN UPPER LOW FINALLY OPENS UP AND LIFTS OUT
TUES NIGHT AND EARLY WEDNESDAY WITH SOME LIFT RETURNING TO THE NORTH
TEXAS. AT THIS TIME...WE FEEL MOISTURE WILL BE TOO LIMITED FOR
PRECIPITATION BUT WILL MONITOR CLOSELY. WE CONTINUE TO UNDERCUT MOS
HIGH TEMPERATURES SINCE THE COLD AIRMASS IS 5-7 KFT DEEP WITH ONLY A
SLOW MODIFICATION BY THURSDAY.
NEXT COLD FRONT IS EXPECTED TO ARRIVE FRIDAY...AS ANOTHER SHORTWAVE
DISTURBANCE MOVES SOUTHEAST ACROSS THE FRONT RANGE OF THE ROCKIES.
GFS IS THE FASTEST WITH THE COLD FRONT...WHILE THE SREF/CANADIAN/AND
ARE ECMWF SLOWER. FOR NOW...WILL LEAN TOWARD A SLOW CONSENSUS ON THE
FRONT WITH WARMER TEMPERATURES FRIDAY THAN WHAT THE MAV MOS
GUIDANCE. WE WILL ALSO LEAVE THIS PERIOD DRY WITH UNCERTAINTIES ON
MOISTURE AVAILABILITY AND TIMING OF BOTH SURFACE AND UPPER LEVEL
FEATURES.
05/42
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 41 45 38 40 29 / 80 100 90 60 20
WACO, TX 48 49 39 44 30 / 70 100 90 60 20
PARIS, TX 49 50 38 44 29 / 100 100 80 70 20
DENTON, TX 38 42 37 38 27 / 70 100 80 60 20
MCKINNEY, TX 42 45 37 41 29 / 100 100 80 60 20
DALLAS, TX 43 47 38 41 30 / 90 100 90 60 20
TERRELL, TX 49 49 39 44 30 / 100 100 90 70 20
CORSICANA, TX 52 52 40 45 31 / 70 100 90 70 20
TEMPLE, TX 54 54 40 46 30 / 80 100 90 60 20
MINERAL WELLS, TX 37 41 34 36 26 / 40 90 70 60 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
325 AM CST SUN DEC 4 2011
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
324 AM CST SUN DEC 4 2011
MAIN FORECAST CONCERN NOW THAT THE PRECIPITATION IS
EXITING/DIMINISHING IS WHEN CLOUDS WILL CLEAR.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING STILL OVER THE EAST PACIFIC AND ALONG THE EAST COAST
OF THE U.S....AND TROUGHING IN-BETWEEN FROM HUDSON BAY SOUTHWEST
INTO ARIZONA. IMPORTANT FEATURES TO NOTE INCLUDE A SHORTWAVE NEAR
EAU CLAIRE WI ON THE EAST SIDE OF THE UPPER TROUGH...AND TWO
SHORTWAVES OVER MONTANA ON THE BACK SIDE OF THE UPPER TROUGH. THE
FORMER SHORTWAVE IN CONJUNCTION WITH PLENTIFUL MOISTURE AND LOW TO
MID-LEVEL FRONTOGENESIS BROUGHT THE WIDESPREAD PRECIPITATION TO THE
AREA LAST NIGHT. DRY SLOT NOTED IN WATER VAPOR COMBINED NOW WITH THE
SHORTWAVE MOVED THROUGH...RESULTING IN SOME SUBSIDENCE...HAS ALLOWED
PRECIPITATION TO REALLY DIMINISH DURING THE PAST 4-6 HOURS. IT
APPEARS MODELS YESTERDAY MAY HAVE OVERDONE THE LOW LEVEL ISENTROPIC
LIFT FOR THE CURRENT EARLY MORNING HOURS... GIVEN THAT THEY NOW SHOW
NO ISENTROPIC LIFT AND SEEING THE PRECIPITATION DIMINISH ON RADAR.
THEREFORE...THE CONCERN ABOUT THE DRY SLOT CLEARING OUT ICE AND
RESULTING IN FREEZING PRECIPITATION IS NOT AS GREAT. IN ADDITION...
SURFACE TEMPERATURES HAVE STRUGGLED TO FALL BELOW FREEZING WHERE IR
CLOUD TOP TEMPERATURES INDICATE ICE HAS BEEN LOST. REGARDING THE
SURFACE...SEA LEVEL PRESSURE ANALYSIS SHOWS A 1008MB LOW NEAR
MANITOWIC WI. PLENTY OF CLOUDS EXTEND WEST FROM THE LOW...BACK
INTO THE EASTERN DAKOTAS. UPSTREAM...ANOTHER BUT MUCH WEAKER SURFACE
LOW IS NOTED NEAR WILLISTON ASSOCIATED WITH ONE OF THE MONTANA
SHORTWAVES.
TODAY AND TONIGHT...A SHORTWAVE IN EASTERN MONTANA IS PROGGED TO
MOVE INTO SOUTH DAKOTA TODAY AND INTO NORTHWEST WISCONSIN TONIGHT.
THE TRACK OF THE SHORTWAVE SUGGESTS ALL OF THE FORCING WILL STAY
NORTH AND WEST OF THE AREA. THIS IS CONFIRMED TOO BY QG PLOTS. IN
ADDITION...IT APPEARS MUCH OF THE CLOUD COVER ASSOCIATED WITH THE
SHORTWAVE WILL STAY TO THE NORTHWEST. SO THIS LEAVES THE CURRENT
CLOUD COVER AND SYSTEM GOING THROUGH THE MAIN CONCERN. WITH STRATUS
EXTENDING SO FAR WEST...GRADUAL SUBSIDENCE OCCURRING TODAY IN THE
WAKE OF THE SYSTEM AND THE LOW SUN ANGLE...THINKING A VERY
PESSIMISTIC TREND MIGHT BE THE WAY TO GO. LIKE THE 04.00Z NAM
INDICATING THE STRATUS STAYS IN PUT ACROSS THE AREA TODAY WITH ONLY
SLOW CLEARING TONIGHT FOR WESTERN AREAS. CONCERNED THAT EVEN THE NAM
MIGHT BE TOO FAST TONIGHT AS THE 900-950MB WINDS TURN FROM THE
NORTHWEST TO NORTH. COMBINED WITH THE RECENT MOISTURE...CLOUDS MAY
ACTUALLY LOWER IN CEILING HEIGHT VERSUS CLEARING. LAST CONCERN IS
PRECIPITATION...BOTH THIS MORNING AND POSSIBLY OUT OF THE STRATUS
DECK TONIGHT. GIVEN DIMINISHING RADAR RETURNS AND DRY FORECASTS
INDICATED BY THE 04.00Z NAM/GFS/ECMWF FOR 12-18Z TODAY...HAVE REALLY
DRIED OUT THIS MORNING. IN FACT...THERE MAY NOT BE MUCH GOING ON
AFTER 12Z. WITH PRECIPITATION RAPIDLY DIMINISHING...WILL CANCEL THE
ADVISORY HERE AT 4 AM. TONIGHT...THE 04.00Z NAM/GFS SHOW SOME LIGHT
QPF OVER THE NORTH HALF OF WISCONSIN. APPEARS TO RESULT FROM LOW
LEVEL CONVERGENCE...ASSOCIATED WITH SURFACE TROUGHING LINGERING BACK
FROM THE CURRENT AREA OF LOW PRESSURE NEAR GRB. HAVE ADDED A 20
PERCENT CHANCE OF SNOW INTO THE FORECAST TO ACCOUNT FOR THIS
POSSIBILITY. OTHERWISE...TEMPERATURES LOOK LIKE THEY SHOULD STRUGGLE
TO RISE TODAY WITH 850MB TEMPS FALLING TO AT LEAST -6 TO -8C AND
CLOUDS STAYING PUT. MAYBE A 1 OR 3 DEGREE F RISE IS POSSIBLE FROM
THE 6 AM TEMPERATURE. WITH MORE CLOUDS ANTICIPATED TONIGHT...BROUGHT
LOW TEMPERATURES UP A FEW DEGREES...ESPECIALLY ALONG AND EAST OF THE
MISSISSIPPI RIVER WHERE CLOUDS ARE MORE CERTAIN. WHERE CLOUDS CLEAR
OUT...TEMPERATURES COULD FALL INTO THE UPPER SINGLE DIGITS.
MONDAY THROUGH TUESDAY NIGHT...BIG STORY/CONCERN HERE IS FORECASTING
WHEN THE STRATUS WILL DISSIPATE AND ANY POTENTIAL PRECIPITATION OUT
OF IT. UPPER TROUGH SITUATED OVER THE NORTHERN PLAINS IS FORECAST TO
MARCH SOUTHEAST DURING THIS PERIOD...IN RESPONSE TO A POWERFUL UPPER
TROUGH DIGGING FORMING OVER CENTRAL CANADA. NORTH TO NORTHEAST LOW
LEVEL FLOW IS LIKELY MONDAY INTO MONDAY NIGHT WITH HIGH PRESSURE
BUILDING INTO THE NORTHERN PLAINS. THIS FLOW SHOULD DO A DECENT JOB
IN HOLDING IN THE STRATUS BELOW THE SUBSIDENCE INVERSION...UNTIL
MAYBE LATE MONDAY NIGHT WHEN THERE IS SUGGESTION THE FLOW BACKS
NORTHWEST TO BRING IN SOME DRIER LOW LEVEL AIR. IN ADDITION...THAT
TROUGH MENTIONED IN THE TONIGHT DISCUSSION IS PROGGED TO DROP
SOUTHWEST DUE TO THE LOW LEVEL FLOW. CONVERGENCE ALONG THIS TROUGH
COULD RESULT IN SOME FLURRY ACTIVITY AND HAVE ADDED IT TO THE
FORECAST. 04.00Z CANADIAN MODEL IS EVEN MORE AGGRESSIVE AND SHOWING
A FEW HUNDREDTHS. IF OTHER MODELS...SUCH AS THE NAM/GFS START TO
SHOW THIS IN LATER RUNS...MAY NEED TO HAVE SOME HIGHER CHANCES
ADDED. BETTER POTENTIAL FOR CLEARING EXISTS TUESDAY AS THE SURFACE
RIDGE MOVES IN AT THE SAME TIME WITH DAYTIME HEATING...SO INDICATED
CLEARING STARTING HERE. UPPER RIDGING THEN BUILDS OVER THE AREA FOR
TUESDAY NIGHT AHEAD OF THE POWERFUL UPPER TROUGH...MAINTAINING DRY
CONDITIONS WITH GENERALLY MOSTLY CLEAR SKIES. FOR TEMPERATURES...
LOOK FOR A COOLING TREND AS THE UPPER TROUGH MOVES IN. DID RAISE LOW
TEMPERATURES UP MONDAY NIGHT IN THE CLOUDY SKY AREA...CLOSER TO THE
2 METER NAM12 GUIDANCE. OTHERWISE...A BLEND OF GUIDANCE SEEMED
REASONABLE.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
324 AM CST SUN DEC 4 2011
AFTER WHAT WAS SOME UNCERTAINTY IN THE LONG TERM FORECAST...CAUSED
ESPECIALLY BY THE 03.12Z ECMWF SUGGESTING A POSSIBLE ADVISORY-TYPE
SNOW MOVING THROUGH FRIDAY/FRIDAY NIGHT...ALL MODELS HAVE COME BACK
INTO GREAT AGREEMENT ON THE UPPER AND SURFACE PATTERNS THROUGHOUT
THE LONG TERM. IN FACT...THEY LOOK A LOT LIKE WHAT WAS SHOWN BY THE
03.00Z CYCLE. SO FOR NOW WILL CONSIDER THE 03.12Z ECMWF AN ODD
OUTLIER. A WEST-NORTHWEST FLOW UPPER PATTERN BEGINS THE LONG
TERM...ON THE SOUTH SIDE OF THE POWERFUL TROUGH DROPPING INTO
SOUTHERN CANADA. A COLD FRONT LOOKS TO SLIDE THROUGH THE FORECAST
AREA ON WEDNESDAY...ENDING A BRIEF WARM SURGE ALOFT CAUSED BY THE
UPPER RIDGE. THEN FOR WEDNESDAY NIGHT AND THURSDAY...A SHORTWAVE
TROUGH IS FORECAST TO DIG DOWN THE WEST SIDE OF THE CANADA UPPER
TROUGH...CAUSING AN UPPER JET TO STRENGTHEN DOWNSTREAM OVER NORTHERN
WISCONSIN. RIGHT ENTRANCE REGION FORCING OF THIS JET SHOULD INDUCE
SOME MID-LEVEL FRONTOGENESIS...AND COMBINED WITH A LITTLE MOISTURE
MAY PRODUCE A BAND OF LIGHT SNOW OVER FAR SOUTHERN SECTION THURSDAY
NIGHT. INCLUDED A 20 PERCENT CHANCE FOR THIS. BIGGER IMPACT IS ON
FRIDAY WHEN THE SHORTWAVE TROUGH MOVES ACROSS...CAUSING 850MB TEMPS
TO TANK FROM -9 TO -13C ON THURSDAY TO AROUND -20C ON FRIDAY.
NEEDLESS TO SAY...BELOW NORMAL TEMPERATURES LIKELY. A DRY AND SLOW
WARMING TREND SHOULD THEN ENSUE HEADING INTO THE WEEKEND IN RESPONSE
TO THE MODELS FORECASTING THE UPPER FLOW BECOMING MORE ZONAL. IN
FACT...THE LATEST 04.00Z ECMWF SUGGESTS HIGHS APPROACHING 40 FOR
NEXT SUNDAY AS A SURGE OF DOWNSLOPED WARMED PACIFIC AIR FLOWS INTO
THE AREA.
&&
.AVIATION...THROUGH 18Z SUNDAY
1130 PM CST SAT DEC 3 2011
SNOW WILL CONTINUE TO DIMINISH OVERNIGHT AS THE STORM SYSTEM PULLS
NORTHEAST. VSBYS SHOULD HOLD IN THE 3-5SM WITH -SN OR BR FOR MUCH OF
SUNDAY MORNING THOUGH. -FZDZ DOESN/T LOOK LIKE A CONCERN FOR
KRST/KLSE NOW AS SATELLITE TRENDS AND RH FIELDS SUGGEST THE DRIER
MID LEVELS WOULD STAY SOUTH OF THE TAF SITES...AND THUS KEEP THE ICE
FREE CLOUDS - AND POTENTIAL FZDZ MAKERS - SOUTH. STILL...SOMETHING
TO MONITOR.
CIGS WILL BE A BIGGER CONCERN AS THE LOW LEVEL MOISTURE REMAINS
ENTRENCHED ACROSS THE AREA. 00Z NAM NOW MORE SUGGESTIVE OF HANGING
ONTO MVFR/IFR CONDITIONS FOR MUCH OF TODAY INTO TONIGHT. SOME HINTS
OF A BRIEF BREAK INTO SCT SUN NIGHT...BUT CONFIDENCE ISN/T HIGH
ENOUGH AND WILL HOLD WITH CIGS THROUGH 06Z MON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
324 AM CST SUN DEC 4 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1037 PM CST SAT DEC 3 2011
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATED...CONCERNING HEADLINES.
AVAILABLE REPORTS IN THE ADVISORY AREA SO FAR THIS EVENING RANGE
UP TO 2 INCHES. IR LOOP SHOWS BEST ENHANCEMENT HAS QUICKLY SHIFTED
NORTHEASTWARD INTO UPPER MICHIGAN. RADAR AND OBS ACROSS THE REGION
INDICATE THE RAIN SNOW LINE EXTENDS FROM NORTHWEST IOWA TO RST TO
STE TO JUST SOUTH OF IMT. A SURFACE LOW WAS OVER SOUTHERN IOWA
EARLY THIS EVENING AND WILL BE ENTERING SOUTHWEST WISCONSIN LATE
THIS EVENING AND NEARLY TRACKING ALONG THE RAIN SNOW LINE
OVERNIGHT. A LARGE AREA OF RAIN WAS IN THE WARM SECTOR OF THE LOW
OVER IOWA AND SOUTHERN WISCONSIN MOVING TOWARD EASTERN WISCONSIN.
PARTS OF EASTERN WISCONSIN MAY SEE UP TO AN ADDITIONAL INCH OF
RAIN OVERNIGHT.
BUT BACK TO THE ADVISORY...BEST SNOW GROWTH REGION WAS OVER
NORTHWEST WISCONSIN AND MAY INCLUDE WESTERN PORTIONS OF ONEIDA AND
VILAS COUNTIES. THIS SNOW GROWTH REGION IS PROGGED TO SAG INTO
NORTH CENTRAL WISCONSIN OVERNIGHT AS THE H8 LOW AND SURFACE LOW
TRACKS OVER. NOT OUT OF THE QUESTION A WARNING MAY BE NEEDED AS
THESE MORE FAVORABLE DYNAMICS PLAY A ROLE...BUT FOR NOW WILL
CONTINUE THE HIGH END ADVISORY.
TDH
&&
.PREV DISCUSSION...ISSUED AT 505 PM CST SAT DEC 3 2011...
SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DEVELOPING
LOW PRESSURE SYSTEM MOVING NORTHEAST OVER SOUTH-CENTRAL KANSAS JUST
AHEAD OF A SHORTWAVE TROUGH. ATTACHED TO THE SURFACE LOW TO THE
NORTHEAST RUNS A COLD FRONT OVER CENTRAL IOWA INTO NORTHWEST
WISCONSIN. FIRST BATCH OF PRECIP IS RIDING ALONG THE 850MB
BAROCLINIC ZONE OVER THE SOUTHEASTERN HALF OF WISCONSIN THOUGH SOME
BREAKS ARE SPREADING OVER EASTERN IOWA AND NORTHERN ILLINOIS...THAT
MAY SPELL A BREAK IN THE PRECIP FOR A BRIEF PERIOD LATE THIS
AFTERNOON OVER E-C WISCONSIN. THE MAIN AXIS OF PRECIP...HOWEVER...
EXISTS JUST TO THE EAST OF THE SURFACE LOW ON THE NOSE OF A 60 KT
LLJ AND UPPER DIVERGENT AREA WITHIN THE COUPLED JET. SOME HIGHER
REFLECTIVITIES ARE ALSO DEVELOPING OVER WESTERN WISCONSIN WITHIN A
STRENGTHENING FGEN ZONE...SO WILL JUST START THE WINTER HEADLINES
WITH THE AFTERNOON PACKAGE. AS THE LOW TRACKS NORTHEAST OVER THE
NEXT 24 HOURS...THE OBVIOUS CONCERNS ARE SNOW AMOUNTS AND
HEADLINES.
TONIGHT...FOLLOWED A SREF/GFS BLEND TONIGHT...WHICH SPLITS THE
DIFFERENCE BETWEEN THE STRONGER NAM AND WEAKER ECMWF WHILE KEEPING
THE CONSENSUS TRACK. LOW PRESSURE OVER THE CENTRAL PLAINS WILL
RAPIDLY MOVE NE TOWARDS THE MID-MISSISSIPPI VALLEY THIS
EVENING...AND NORTHERN LAKE MICHIGAN BY 12Z SUNDAY. AHEAD OF THE
LOW...A BEEFY LLJ WILL SHIFT INTO SOUTHERN WISCONSIN THIS
EVENING...THEREBY INCREASING CONVERGENCE ALONG THE STALLED
BAROCLINIC ZONE STRETCHING ACROSS THE STATE...AND 850-700MB FGEN IN
THE PROCESS. COMBINED WITH STRONG QG FORCING FROM SHORTWAVE ENERGY
AND A WIDE OPEN GULF (PWATS 150-200 PCT OF NORMAL)...THE BEEFY SLUG
OF PRECIP OVER THE PLAINS WILL HAVE NO TROUBLE SPREADING ACROSS THE
STATE THIS EVENING. PTYPE REMAINS PROBLEMATIC AS THE 12Z MODEL RUNS
HAVE TRENDED SLIGHTLY WARMER WITH THE THERMAL PROFILE AS THE LOW
PUSHES WARMER AIR ALOFT SLIGHTLY FARTHER NORTH THAN PREVIOUS RUNS.
THIS WILL PLACE THE RAIN-SNOW MIX AREA FROM WOOD COUNTY TO NORTHERN
OCONTO AND MARINETTE. NORTH OF THE RAIN-SNOW LINE SHOULD RESIDE THE
AXIS OF HEAVIEST SNOWFALL...WHICH LINES UP WITH THE EXTRAPOLATED
SOUTHERN EDGE OF THE COMMA HEAD FROM APPROX MERRILL TO CRANDON.
WITH SLIGHTLY COLDER AIR IN PLACE COMPARED TO THE FIRST SNOW STORM IN
NOVEMBER...SNOW RATIOS WILL RUN BETWEEN 10-14:1 OVER THIS AREA
ACCORDING TO THE COBB SNOWFALL ALGORITHM. WITH QPFS AROUND 0.4 TO
0.5 INCHES...THIS AMOUNTS TO A GOOD 4-6 INCH SWATH OF SNOW TONIGHT
(5 TO 7 INCHES OVERALL)...THOUGH THE BULK OF THE PRECIP WILL LIKELY FALL
THIS EVENING. THE FOX VALLEY AND LAKESHORE WILL RESIDE WITHIN THE
WARM SECTOR OF THE STORM...WHICH MEANS MOSTLY RAIN TONIGHT...THOUGH
SOME SNOW MAY MIX IN LATE. ENTERTAINED SOME THOUGHTS OF UPGRADING TO
A WARNING GIVEN THE HEAVY SNOW OBS UPSTREAM...BUT GIVEN THE
RELATIVELY LOW IMPACT OF THE SNOW (DURING THE NIGHT ON A
WEEKEND)...WILL STICK WITH ADVISORY HEADLINES. ALSO THOUGHT ABOUT
TRIMMING THE ADVISORY TO THE NW BY A ROW OF COUNTIES...BUT
COORDINATION WITH SURROUNDING OFFICES YIELDED A RELUCTANCE...DUE TO
THE SLOPPINESS OF THE MIX AND POTENTIAL FOR FREEZING DRIZZLE. AS A
RESULT...WILL KEEP CURRENT HEADLINES AS THEY CURRENTLY STAND BUT
STRESS THE HEAVY SNOWFALL RATES ARRIVING THIS EVENING.
SUNDAY...THE LOW PRESSURE WILL QUICKLY EXIT TO SOUTHEAST ONTARIO BY
18Z SUNDAY BUT WILL HAVE THE BACK EDGE OF THE COMMA HEAD SHIFTING NE
OVER N-C AND FAR NORTHEAST WISCONSIN. SOME MID-LEVEL FGEN WILL
LINGER WHICH WILL RESULT IN ANOTHER HALF INCH TO AN INCH OVER N-C
WISCONSIN EARLY IN THE MORNING. BUT OTHERWISE...SNOW WILL BE
TAPERING DOWN TO JUST FLURRIES IN THE MORNING...WHILE COLDER AIR
FILTERS ACROSS THE REGION. LOW LEVEL TROUGHINESS AND CYCLONIC FLOW
WILL HANG AROUND FOR MUCH OF THE DAY...SO NOT ANTICIPATING MUCH
CLEARING TOMORROW. HIGHS MAINLY IN THE LOW TO MIDDLE 30S.
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...THE MAIN FCST
CONCERNS WILL BE MINOR LAKE EFFECT SNOW POTENTIAL OVER NORTHERN
WI EARLY IN THE PERIOD...THEN THE POTENTIAL FOR SNOW AND MUCH
COLDER TEMPERATURES WITH AN ARCTIC FRONTAL PASSAGE LATE NEXT
WEEK.
A STRONG...HIGH AMPLITUDE RIDGE WILL COVER THE EASTERN PACIFIC...
WESTERN CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...
WITH A POSITIVELY-TILTED UPPER TROF EXTENDING FROM CENTRAL CANADA
INTO THE SOUTHWEST UNITED STATES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON TUESDAY...WITH LITTLE IMPACT ON OUR WEATHER. SHORT-WAVE
ENERGY WILL TOP THE WESTERN RIDGE EARLY NEXT WEEK...THEN EVENTUALLY
HELP TO CARVE A BROAD TROF OVER THE CENTRAL U.S. BY THU/FRI. A
SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN WI LATE IN THE WEEK...
WITH H8 TEMPS PLUMMETING TO AROUND -20 C. THIS WILL LEAD TO OUR
COLDEST TEMPERATURES SO FAR THIS SEASON.
A LARGE RIDGE OF HIGH PRESSURE WILL BE CENTERED OVER THE NORTHERN
ROCKIES AND NORTHERN PLAINS SUN NGT INTO MON...WITH COLD NORTH
FLOW RESULTING IN SCT LAKE-EFFECT SNOW SHOWERS OVER MAINLY NC WI.
THE SNOW SHOWERS MAY LINGER INTO MONDAY NIGHT...BUT SHOULD COME TO
AN END ON TUESDAY AS THE RIDGE AXIS PUSHES ACROSS WI.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING SOMETIME DURING
THE THU/FRI TIME FRAME. DURING THIS PERIOD...LLVL FLOW IS EXPECTED
TO BE TOO WESTERLY FOR LK-EFFECT. THE ECMWF AND A FEW OF THE GFS
ENSEMBLE MEMBERS SUGGEST THAT A SFC WAVE WILL DEVELOP ALONG THE
ARCTIC BOUNDARY LATE IN THE WEEK...AS THE RRQ OF A STRONG UPPER
LEVEL JET PULLS THROUGH THE REGION. IF THIS PLAYS OUT...WE COULD
BRING SEE SEVERAL INCHES OF POWDERY SNOW SOMETIME DURING THE
THURSDAY NIGHT TO SATURDAY PERIOD. FOR NOW...WILL FOLLOW THE
CONCENSUS OF AREA OFFICES...AND JUST MENTION SMALL POPS ACROSS OUR
SOUTHERN AND EASTERN COUNTIES ON THU NGT/FRI. THERE IS A HIGHER
DEGREE OF CONFIDENCE IN A TREND TOWARD MUCH COLDER TEMPERATURES
LATE IN THE WEEK...ALTHOUGH THE NEW ECMWF IS SLOWER WITH THE
TIMING OF THE ARCTIC BOUNDARY. SUBSEQUENT FCSTS SHOULD BE BETTER
ABLE TO PINPOINT THE FRONTAL TIMING AND SNOWFALL POTENTIAL LATE
NEXT WEEK.
&&
.AVIATION...IFR TO LIFR CIGS AND VSBYS WILL CONTINUE OVER CENTRAL
AND NORTH CENTRAL WISCONSIN AS STEADY SNOWS CONTINUE TO AFFECT THE
AREA OVERNIGHT. MAINLY LIFR TO IFR CIGS WITH IFR VSBYS WITH RAIN
AND FOG TO IMPACT EASTERN WISCONSIN. PERSISTENT RAIN/SNOW LINE
CONTINUES TO RUN FROM AROUND ISW TO JUST SOUTH OF IMT LATE THIS
EVENING. CIGS AND VSBYS TO GRADUALLY IMPROVE TO MVFR CONDITIONS
SUNDAY AS THE LOW PRESSURE SYSTEM DEPARTS TO THE NORTHEAST.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ005-010>013-
018-019-021-030-035.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
912 AM CST SUN DEC 4 2011
.DISCUSSION...
340 AM CST
HIGHLIGHTS THIS WEEK WILL INCLUDE RAIN COMING TO AN END...POSSIBLE
SN/RASN/RA ACROSS THE SOUTHEAST MONDAY...LES POTENTIAL FOR
LAKE/COOK LATE SUNDAY NIGHT INTO MONDAY...TRANSITIONING SOUTH TO
LAKE/PORTER INDIANA BY TUESDAY...A FEW DAYS OF QUIET...FOLLOWED
BY A LATE CLIPPER AND SNOW POTENTIAL AND FINALLY A BLAST OF COLD
BY NEXT WEEKEND.
THE EARLY MORNING SURFACE MAP SHOWED THE SURFACE LOW THAT HAS
BEEN BRINGING THE WET AND ACTIVE WEATHER TO THE AREA
TODAY...CONTINUING TO LIFTING NORTH THROUGH CENTRAL WISCONSIN.
MEANWHILE AN ATTENDANT COLD FRONT LAY ROUGHLY ACROSS THE
MISSISSIPPI RIVER...SOUTHWEST NEARLY TO ST LOUIS. THIS FRONT WILL
CONTINUE TO SLOWLY SWEEP FROM WEST TO EAST THIS MORNING EVENTUALLY
PUSHING ITSELF AND THE PRECIP EAST. THE MOST WIDE SPREAD ECHOES HAVE
PUSHED EAST AND ONLY A FEW SCATTERED SHOWERS ARE LOCATED WITH THE
ACTUAL FRONT. ACROSS EAST CENTRAL IOWA...TEMPERATURES HAVE
DROPPED ENOUGH THAT -SN WAS REPORTED...BUT CLOUD TOPS HAVE WARMED
ENOUGH AND ARE WARMER THAN -10C. THIS MEANS THAT THERE IS NO
LONGER ICE INTRODUCTION INTO THE SATURATED LAYERS BELOW...AND A
FEW LOCATIONS REPORTED U.P. AND OR FZDZ. FOR OUR AREA...AFTER THE
FRONT MOVES THROUGH...LOWER LEVEL MOISTURE WILL REMAIN BUT
PROFILES ARE STILL INDICATIVE OF LIQUID PRECIP AND SURFACE TEMPS
WILL REMAIN ABOVE FREEZING.
THE HRRR AND RUC BOTH HAVE A GOOD HANDLE ON THE WESTERN EDGE OF THE
PRECIP AND FRONTAL LOCATION...AND MOST OF IT SHOULD CLEAR THE
ROCKFORD CORRIDOR NEAR SUNRISE...WITH CHICAGO AND EAST JUST A FEW
HOURS BEYOND. WHILE LOWER LEVEL RH WILL REMAIN PREVALENT WITH AND
SHORTLY BEYOND FROPA...MOISTURE ABOVE -10C WILL DISAPPEAR AND
THERE MAY BE SOME LINGERING DZ INTO THE EARLY MORNING HOURS. THE
BIG PUSH OF COLDER AIR ISNT EXPECTED UNTIL LATER THIS EVENING AND
TEMPERATURES WILL REMAIN ABOVE FREEZING...SO NO CONCERN OVER ANY
OTHER PRECIP TYPES THIS MORNING. HIGH TEMPS WILL GENERALLY BE
SEEN EARLY TODAY...AND SLOWLY FALL THROUGH THE DAY. WINDS WILL
ABATE AS HIGH PRESSURE AND A PERIOD OF DRY...SLOWLY MOVE IN.
THE MAIN UPPER LEVEL TROUGHING THAT STRETCHES FROM ROUGHLY
SASKATCHEWAN...SOUTHWEST THROUGH THE FOUR CORNERS REGION WILL NOT
HAVE MUCH REASON TO MOVE UNTIL THE START OF THE WORKWEEK. PRESENT
SHORTWAVE SEEN ON WATER VAPOR IMAGERY ROUNDING THE BASE OF THE
TROUGH...ACROSS SOUTHERN ARIZONA...WILL DAMPEN SOME AS IT
GETS EJECTED ON THE EASTERN FLANK TODAY AND TONIGHT. AS IT DOES
THIS...IT WILL HELP TO AMPLIFY AN INVERTED TROUGH THAT WILL NOSE
ITS WAY TOWARDS THE OHIO VALLEY...EVENTUALLY SPAWNING A WEAK LOW
ACROSS THE TENNESSEE VALLEY. GUIDANCE HAS BEEN HEMMING AND HAWING
WITH JUST HOW FAR NORTH TO BRING THE PRECIP WITH THIS
FEATURE...AND JUST HOW MUCH OF IT WILL REACH INTO THE SOUTHEASTERN
CORNER OF THE CWA. THE LATEST FORECAST TRENDS HAVE BACKED OFF FROM
PREVIOUS...AND DID SCALE BACK ON POPS AS WELL AS COVERAGE. STILL A
LITTLE UNCERTAIN WITH WHERE THE RASN VS STRAIGHT RA LINE WOULD BE
AND WILL MAINTAIN A SORT OF MIX. ALSO OF NOTE FOR COASTAL
LOCATIONS IN THIS SAME TIME FRAME /AS THE INV TROF-LOW SLIDE EAST/
IS THE CHANCE FOR LES. THERMAL PROFILES ACROSS THE SOUTHERN LAKE
WILL BECOME INCREASINGLY UNSTABLE WITH LAKE SURFACE TO H85 DELTA
T`S REACHING THE 12-15C RANGE. EXPECT WEAK SHOWERS TO BEGIN TO
STRETCH FROM LAKE COUNTY IL...EVENTUALLY SOUTH TO COOK AND
GRADUALLY INTO THE MORE TYPICAL LAKE/PORTER IN ORIENTATION. QPF
AMOUNTS NOT LOOKING VERY IMPRESSIVE DURING THE SHORT DURATION AND
WOULD ONLY EXPECT ANYWHERE FROM A TRACE TO MAYBE A TENTH OR TWO OF
ACCUMULATION CLOSE TO THE LAKE TOMORROW AND INTO TOMORROW NIGHT.
THIS WILL ALL BE FOLLOWED BY A FEW DAYS OF QUIET AS ANOTHER RIDGE
OF HIGH PRESSURE SWINGS IN FROM THE NORTHWEST.
A LATE WEEK SYSTEM IS STILL PART OF A LOW CONFIDENCE FORECAST.
GFS HAD BEEN ADVERTISING A WEAK CLIPPER DROPPING FROM THE NORTHERN
PLAINS... AND PREVIOUS EC SOLNS HAD SIMILAR...BUT THE 12Z FLIPPED AND
DEVELOPED A SURFACE LOW THAT LIFTS THROUGH THE MISSISSIPPI
VALLEY...INTO NORTHERN INDIANA...NORTHEAST THROUGH EASTERN
ONTARIO. CONFIDENCE AT THIS POINT ON THAT EURO SOLN IS LOW AND
WILL KEEP THE CHANCE OF SNOW AND NOT BUMP UP (OR DOWN) ANY
CATEGORY UNTIL THE PICTURE IS A LITTLE CLEARER. THE 00Z SOLN BEGAN
TO COME IN AND WAS BACK TO THE ORIGINAL PICTURE WITH THE CLIPPER
RACING THROUGH. DESPITE THE LOWER CONFIDENCE IN THAT FEATURE LATE
THIS WEEK...THE ONE PICTURE OF CLARITY WHAT WILL FOLLOW IT. ALL
LONG RANGE GUIDANCE IS STILL INDICATING THAT THERE WILL BE A LARGE
SURGE OF COLD AIR ENCROACHING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. THERE ARE STILL SOME TIMING DIFFERENCES WITH HOW QUICKLY
THE COLD AIR WILL DUMP IN...WHICH IS DUE IN PART TO THE LARGE
MODEL DIFFERENCES MENTIONED MOMENTS AGO...BUT THE ONE THING THEY
ALL AGREE ON IS HOW COLD THE LOWER LEVELS WILL GET INTO THE
WEEKEND. EVEN A WEEK OUT...THE EC/GFS/GEFS/DGEX/GEM(NHEM THROUGH
F144) ALL HIGHLIGHT H85 TEMPS PLUMMETING TO -16 TO -18
DEGREES...OR EVEN A FEW DEGREES COLDER. TRANSLATE THAT TO THE
SURFACE AND IT WOULD BE POSSIBLE THAT HIGHS WOULD STRUGGLE TO GET
OUT OF THE TEENS FOR MANY LOCATIONS AND OVERNIGHT LOWS LEADING
INTO THE WEEKEND WOULD DIVE BOMB TO THE SINGLE DIGITS /BUT LIKELY A
SMIDGEN WARMER IN THE CHICAGO METRO/. WITH THAT FORECAST STILL
BEING OUT 6-7 DAYS...AND A SLEW OF OTHER WEATHER GOING ON THROUGH
THE EARLY WEEK... WILL ONLY CONTINUE TO TREND DOWN FROM THE
INHERITED LONG RANGE FORECAST. THE BIG SAVING GRACE IS THE LACK OF
SOLID SNOW PACK. IF THAT WERE PRESENT...IT WOULD BE MUCH COLDER.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LOW MVFR TO IFR POST FRONTAL CIGS MOVING BACK ACROSS THE
TERMINALS LATER THIS MORNING.
KJB
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE OVER NORTHERN LAKE MICHIGAN MOVING QUICKLY NORTHEAST
THIS MORNING. MOST OF THE RAIN HAS MOVED OUT OF THE AREA. ONLY A
FEW LIGHT SHOWERS REMAIN ALONG THE COLD FRONT...WHICH STRETCHES
FROM THE LOW TO JUST WEST OF RFD TO STL. JUST KEPT A VCSH IN FOR A
FEW HOURS TO COVER A POSSIBLE BRIEF LIGHT SHOWER THROUGH MID
MORNING. STRONG SSW WINDS STILL GUSTING TO AROUND 25 KTS EARLY
THIS MORNING. WINDS WILL SHIFT WEST WITH COLD FRONTAL PASSAGE MID
MORNING AND DIMINISH. MAY STILL SEE SOME GUSTS TO AROUND 20 KT OR
SO THROUGH MIDDAY. WINDS WILL BECOME NORTHWEST AND FALL TO LESS
THAN 10 KT BY LATE AFTERNOON.
MAIN ISSUE TODAY WILL BE LOW CEILINGS...PRESENTLY RUNNING AROUND
1000-1500 FT. SOME IFR NOTED OVER IA AND WESTERN IL BEHIND THE
COLD FRONT. BUT WITH EVERYTHING LIFTING NORTHEAST...AND LOOKING
AT MODEL SOUNDINGS...DONT EXPECT IFR CIGS TO IMPACT THE CHICAGO
AREA TERMINALS. RFD MY FLIRT WITH IFR THROUGH THE MORNING HOURS
AND HAVE COVERED THIS WITH A TEMPO GROUP. SHOULD SEE AN IMPROVING
TREND THROUGH THE AFTERNOON. THE BACK EDGE OF THE STRATUS OVER THE
DAKOTAS...NEB...INTO NW MO IS PUSHING EAST ON SATELLITE IMAGERY.
THERE IS A POSSIBILITY OF STRATUS SCATTERING OUT OVER NORTHERN IL
TOWARDS EVENING OR OVERNIGHT...BUT CONFIDENCE IN THAT HAPPENING IS
LOW AND WILL HANG ON TO MVFR CIGS THROUGH THE NIGHT AT THIS
POINT.
WINDS WILL GRADUALLY VEER NORTH NORTHEAST LATE TONIGHT INTO
MONDAY MORNING. AS COLDER AIR MOVES DOWN THE LAKE...SOME LAKE
EFFECT CLOUDS AND LIGHT SNOW SHOWERS ARE POSSIBLE MONDAY BUT AT
THIS TIME IT APPEARS THE CLOUD DEPTH WILL BE TOO SHALLOW TO
SUPPORT ANY SIGNIFICANT LAKE EFFECT FOR MONDAY.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN MVFR CIGS.
* LOW CONFIDENCE IN CIGS DROPPING INTO THE IFR CATEGORY.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR CIG. CHANCE LIGHT LAKE EFFECT SNOW SHOWERS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...VFR.
ALLSOPP
&&
.MARINE...
133 AM CST
A POWERFUL STORM WAS MOVING THROUGH THE GREAT LAKES THIS MORNING.
LOW PRESSURE WILL MOVE QUICKLY FROM WISCONSIN TO NORTHERN LAKE
MICHIGAN THIS MORNING...THEN ON TO QUEBEC BY EVENING. EAST OF THE
TRACK OF THE LOW A VERY STRONG SOUTHERLY LOW LEVEL JET WAS
OCCURRING...WITH 50 KT WINDS JUST 1 TO 2 THOUSAND FEET OFF THE
SURFACE. A STRONG INVERSION WAS LIMITING MIXING BUT GALE FORCE
WINDS WERE WORKING DOWN TO THE LAKE SURFACE OVER THE SOUTH HALF
WITH SOME GALE FORCE GUSTS ON THE EAST SIDE OF THE NORTH HALF OF
THE LAKE. WINDS SHOULD DROP OFF PRETTY QUICKLY AS THE LOW MOVES
RAPIDLY NORTHEAST TODAY AND GALES SHOULD END BY ABOUT NOON.
PRESENTLY GALE WARNING GOES THROUGH MID AFTERNOON BUT IT MAY BE
CANCELED EARLY. WINDS WILL VEER FROM SOUTH TO NORTHWEST THROUGH
THE COURSE OF THE DAY.
TONIGHT THROUGH MONDAY ANOTHER LOW WILL MOVE FROM THE TEXAS COAST
UP THROUGH THE OHIO VALLEY WHILE STRONG HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THIS WILL PRODUCE A PERIOD OF NORTHERLY WINDS
ON LAKE MICHIGAN. THE REST OF THE WEEK HIGH PRESSURE WILL DOMINATE
THE CENTRAL U.S. WHILE LOW PRESSURE BECOMES ANCHORED OVER
NORTHEAST CANADA. THIS WILL PRODUCE A PROLONGED PERIOD OF WESTERLY
WINDS OVER LAKE MICHIGAN FROM MID WEEK INTO THE WEEKEND.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 3 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
549 AM CST SUN DEC 4 2011
.DISCUSSION...
340 AM CST
HIGHLIGHTS THIS WEEK WILL INCLUDE RAIN COMING TO AN END...POSSIBLE
SN/RASN/RA ACROSS THE SOUTHEAST MONDAY...LES POTENTIAL FOR
LAKE/COOK LATE SUNDAY NIGHT INTO MONDAY...TRANSITIONING SOUTH TO
LAKE/PORTER INDIANA BY TUESDAY...A FEW DAYS OF QUIET...FOLLOWED
BY A LATE CLIPPER AND SNOW POTENTIAL AND FINALLY A BLAST OF COLD
BY NEXT WEEKEND.
THE EARLY MORNING SURFACE MAP SHOWED THE SURFACE LOW THAT HAS
BEEN BRINGING THE WET AND ACTIVE WEATHER TO THE AREA
TODAY...CONTINUING TO LIFTING NORTH THROUGH CENTRAL WISCONSIN.
MEANWHILE AN ATTENDANT COLD FRONT LAY ROUGHLY ACROSS THE
MISSISSIPPI RIVER...SOUTHWEST NEARLY TO ST LOUIS. THIS FRONT WILL
CONTINUE TO SLOWLY SWEEP FROM WEST TO EAST THIS MORNING EVENTUALLY
PUSHING ITSELF AND THE PRECIP EAST. THE MOST WIDE SPREAD ECHOES HAVE
PUSHED EAST AND ONLY A FEW SCATTERED SHOWERS ARE LOCATED WITH THE
ACTUAL FRONT. ACROSS EAST CENTRAL IOWA...TEMPERATURES HAVE
DROPPED ENOUGH THAT -SN WAS REPORTED...BUT CLOUD TOPS HAVE WARMED
ENOUGH AND ARE WARMER THAN -10C. THIS MEANS THAT THERE IS NO
LONGER ICE INTRODUCTION INTO THE SATURATED LAYERS BELOW...AND A
FEW LOCATIONS REPORTED U.P. AND OR FZDZ. FOR OUR AREA...AFTER THE
FRONT MOVES THROUGH...LOWER LEVEL MOISTURE WILL REMAIN BUT
PROFILES ARE STILL INDICATIVE OF LIQUID PRECIP AND SURFACE TEMPS
WILL REMAIN ABOVE FREEZING.
THE HRRR AND RUC BOTH HAVE A GOOD HANDLE ON THE WESTERN EDGE OF THE
PRECIP AND FRONTAL LOCATION...AND MOST OF IT SHOULD CLEAR THE
ROCKFORD CORRIDOR NEAR SUNRISE...WITH CHICAGO AND EAST JUST A FEW
HOURS BEYOND. WHILE LOWER LEVEL RH WILL REMAIN PREVALENT WITH AND
SHORTLY BEYOND FROPA...MOISTURE ABOVE -10C WILL DISAPPEAR AND
THERE MAY BE SOME LINGERING DZ INTO THE EARLY MORNING HOURS. THE
BIG PUSH OF COLDER AIR ISNT EXPECTED UNTIL LATER THIS EVENING AND
TEMPERATURES WILL REMAIN ABOVE FREEZING...SO NO CONCERN OVER ANY
OTHER PRECIP TYPES THIS MORNING. HIGH TEMPS WILL GENERALLY BE
SEEN EARLY TODAY...AND SLOWLY FALL THROUGH THE DAY. WINDS WILL
ABATE AS HIGH PRESSURE AND A PERIOD OF DRY...SLOWLY MOVE IN.
THE MAIN UPPER LEVEL TROUGHING THAT STRETCHES FROM ROUGHLY
SASKATCHEWAN...SOUTHWEST THROUGH THE FOUR CORNERS REGION WILL NOT
HAVE MUCH REASON TO MOVE UNTIL THE START OF THE WORKWEEK. PRESENT
SHORTWAVE SEEN ON WATER VAPOR IMAGERY ROUNDING THE BASE OF THE
TROUGH...ACROSS SOUTHERN ARIZONA...WILL DAMPEN SOME AS IT
GETS EJECTED ON THE EASTERN FLANK TODAY AND TONIGHT. AS IT DOES
THIS...IT WILL HELP TO AMPLIFY AN INVERTED TROUGH THAT WILL NOSE
ITS WAY TOWARDS THE OHIO VALLEY...EVENTUALLY SPAWNING A WEAK LOW
ACROSS THE TENNESSEE VALLEY. GUIDANCE HAS BEEN HEMMING AND HAWING
WITH JUST HOW FAR NORTH TO BRING THE PRECIP WITH THIS
FEATURE...AND JUST HOW MUCH OF IT WILL REACH INTO THE SOUTHEASTERN
CORNER OF THE CWA. THE LATEST FORECAST TRENDS HAVE BACKED OFF FROM
PREVIOUS...AND DID SCALE BACK ON POPS AS WELL AS COVERAGE. STILL A
LITTLE UNCERTAIN WITH WHERE THE RASN VS STRAIGHT RA LINE WOULD BE
AND WILL MAINTAIN A SORT OF MIX. ALSO OF NOTE FOR COASTAL
LOCATIONS IN THIS SAME TIME FRAME /AS THE INV TROF-LOW SLIDE EAST/
IS THE CHANCE FOR LES. THERMAL PROFILES ACROSS THE SOUTHERN LAKE
WILL BECOME INCREASINGLY UNSTABLE WITH LAKE SURFACE TO H85 DELTA
T`S REACHING THE 12-15C RANGE. EXPECT WEAK SHOWERS TO BEGIN TO
STRETCH FROM LAKE COUNTY IL...EVENTUALLY SOUTH TO COOK AND
GRADUALLY INTO THE MORE TYPICAL LAKE/PORTER IN ORIENTATION. QPF
AMOUNTS NOT LOOKING VERY IMPRESSIVE DURING THE SHORT DURATION AND
WOULD ONLY EXPECT ANYWHERE FROM A TRACE TO MAYBE A TENTH OR TWO OF
ACCUMULATION CLOSE TO THE LAKE TOMORROW AND INTO TOMORROW NIGHT.
THIS WILL ALL BE FOLLOWED BY A FEW DAYS OF QUIET AS ANOTHER RIDGE
OF HIGH PRESSURE SWINGS IN FROM THE NORTHWEST.
A LATE WEEK SYSTEM IS STILL PART OF A LOW CONFIDENCE FORECAST.
GFS HAD BEEN ADVERTISING A WEAK CLIPPER DROPPING FROM THE NORTHERN
PLAINS... AND PREVIOUS EC SOLNS HAD SIMILAR...BUT THE 12Z FLIPPED AND
DEVELOPED A SURFACE LOW THAT LIFTS THROUGH THE MISSISSIPPI
VALLEY...INTO NORTHERN INDIANA...NORTHEAST THROUGH EASTERN
ONTARIO. CONFIDENCE AT THIS POINT ON THAT EURO SOLN IS LOW AND
WILL KEEP THE CHANCE OF SNOW AND NOT BUMP UP (OR DOWN) ANY
CATEGORY UNTIL THE PICTURE IS A LITTLE CLEARER. THE 00Z SOLN BEGAN
TO COME IN AND WAS BACK TO THE ORIGINAL PICTURE WITH THE CLIPPER
RACING THROUGH. DESPITE THE LOWER CONFIDENCE IN THAT FEATURE LATE
THIS WEEK...THE ONE PICTURE OF CLARITY WHAT WILL FOLLOW IT. ALL
LONG RANGE GUIDANCE IS STILL INDICATING THAT THERE WILL BE A LARGE
SURGE OF COLD AIR ENCROACHING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. THERE ARE STILL SOME TIMING DIFFERENCES WITH HOW QUICKLY
THE COLD AIR WILL DUMP IN...WHICH IS DUE IN PART TO THE LARGE
MODEL DIFFERENCES MENTIONED MOMENTS AGO...BUT THE ONE THING THEY
ALL AGREE ON IS HOW COLD THE LOWER LEVELS WILL GET INTO THE
WEEKEND. EVEN A WEEK OUT...THE EC/GFS/GEFS/DGEX/GEM(NHEM THROUGH
F144) ALL HIGHLIGHT H85 TEMPS PLUMMETING TO -16 TO -18
DEGREES...OR EVEN A FEW DEGREES COLDER. TRANSLATE THAT TO THE
SURFACE AND IT WOULD BE POSSIBLE THAT HIGHS WOULD STRUGGLE TO GET
OUT OF THE TEENS FOR MANY LOCATIONS AND OVERNIGHT LOWS LEADING
INTO THE WEEKEND WOULD DIVE BOMB TO THE SINGLE DIGITS /BUT LIKELY A
SMIDGEN WARMER IN THE CHICAGO METRO/. WITH THAT FORECAST STILL
BEING OUT 6-7 DAYS...AND A SLEW OF OTHER WEATHER GOING ON THROUGH
THE EARLY WEEK... WILL ONLY CONTINUE TO TREND DOWN FROM THE
INHERITED LONG RANGE FORECAST. THE BIG SAVING GRACE IS THE LACK OF
SOLID SNOW PACK. IF THAT WERE PRESENT...IT WOULD BE MUCH COLDER.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR CIGS.
* STRONG GUSTY SSW WINDS VEERING WEST AND DIMINISHING BY
AFTERNOON.
* FEW LIGHT SHOWERS THROUGH ABOUT 15Z.
ALLSOPP
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE OVER NORTHERN LAKE MICHIGAN MOVING QUICKLY NORTHEAST
THIS MORNING. MOST OF THE RAIN HAS MOVED OUT OF THE AREA. ONLY A
FEW LIGHT SHOWERS REMAIN ALONG THE COLD FRONT...WHICH STRETCHES
FROM THE LOW TO JUST WEST OF RFD TO STL. JUST KEPT A VCSH IN FOR A
FEW HOURS TO COVER A POSSIBLE BRIEF LIGHT SHOWER THROUGH MID
MORNING. STRONG SSW WINDS STILL GUSTING TO AROUND 25 KTS EARLY
THIS MORNING. WINDS WILL SHIFT WEST WITH COLD FRONTAL PASSAGE MID
MORNING AND DIMINISH. MAY STILL SEE SOME GUSTS TO AROUND 20 KT OR
SO THROUGH MIDDAY. WINDS WILL BECOME NORTHWEST AND FALL TO LESS
THAN 10 KT BY LATE AFTERNOON.
MAIN ISSUE TODAY WILL BE LOW CEILINGS...PRESENTLY RUNNING AROUND
1000-1500 FT. SOME IFR NOTED OVER IA AND WESTERN IL BEHIND THE
COLD FRONT. BUT WITH EVERYTHING LIFTING NORTHEAST...AND LOOKING
AT MODEL SOUNDINGS...DONT EXPECT IFR CIGS TO IMPACT THE CHICAGO
AREA TERMINALS. RFD MY FLIRT WITH IFR THROUGH THE MORNING HOURS
AND HAVE COVERED THIS WITH A TEMPO GROUP. SHOULD SEE AN IMPROVING
TREND THROUGH THE AFTERNOON. THE BACK EDGE OF THE STRATUS OVER THE
DAKOTAS...NEB...INTO NW MO IS PUSHING EAST ON SATELLITE IMAGERY.
THERE IS A POSSIBILITY OF STRATUS SCATTERING OUT OVER NORTHERN IL
TOWARDS EVENING OR OVERNIGHT...BUT CONFIDENCE IN THAT HAPPENING IS
LOW AND WILL HANG ON TO MVFR CIGS THROUGH THE NIGHT AT THIS
POINT.
WINDS WILL GRADUALLY VEER NORTH NORTHEAST LATE TONIGHT INTO
MONDAY MORNING. AS COLDER AIR MOVES DOWN THE LAKE...SOME LAKE
EFFECT CLOUDS AND LIGHT SNOW SHOWERS ARE POSSIBLE MONDAY BUT AT
THIS TIME IT APPEARS THE CLOUD DEPTH WILL BE TOO SHALLOW TO
SUPPORT ANY SIGNIFICANT LAKE EFFECT FOR MONDAY.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE ON CIGS REMAINING 1000-1500 THROUGH THE
MORNING...THEN LIFTING IN THE AFTERNOON. THERE IS A SLIGHT
CHANCE OF IFR CIGS THIS MORNING BUT CONFIDENCE IN THAT HAPPENING
AT ORD/MDW IS LOW.
* MEDIUM CONFIDENCE IN MVFR CIGS HANGING IN THROUGH THE NIGHT.
* HIGH CONFIDENCE IN LIGHT SHOWERS ENDING WITH COLD FRONT PASSAGE
AROUND MID THIS MORNING.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR CIG. CHANCE LIGHT LAKE EFFECT SNOW SHOWERS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...VFR.
ALLSOPP
&&
.MARINE...
133 AM CST
A POWERFUL STORM WAS MOVING THROUGH THE GREAT LAKES THIS MORNING.
LOW PRESSURE WILL MOVE QUICKLY FROM WISCONSIN TO NORTHERN LAKE
MICHIGAN THIS MORNING...THEN ON TO QUEBEC BY EVENING. EAST OF THE
TRACK OF THE LOW A VERY STRONG SOUTHERLY LOW LEVEL JET WAS
OCCURRING...WITH 50 KT WINDS JUST 1 TO 2 THOUSAND FEET OFF THE
SURFACE. A STRONG INVERSION WAS LIMITING MIXING BUT GALE FORCE
WINDS WERE WORKING DOWN TO THE LAKE SURFACE OVER THE SOUTH HALF
WITH SOME GALE FORCE GUSTS ON THE EAST SIDE OF THE NORTH HALF OF
THE LAKE. WINDS SHOULD DROP OFF PRETTY QUICKLY AS THE LOW MOVES
RAPIDLY NORTHEAST TODAY AND GALES SHOULD END BY ABOUT NOON.
PRESENTLY GALE WARNING GOES THROUGH MID AFTERNOON BUT IT MAY BE
CANCELED EARLY. WINDS WILL VEER FROM SOUTH TO NORTHWEST THROUGH
THE COURSE OF THE DAY.
TONIGHT THROUGH MONDAY ANOTHER LOW WILL MOVE FROM THE TEXAS COAST
UP THROUGH THE OHIO VALLEY WHILE STRONG HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THIS WILL PRODUCE A PERIOD OF NORTHERLY WINDS
ON LAKE MICHIGAN. THE REST OF THE WEEK HIGH PRESSURE WILL DOMINATE
THE CENTRAL U.S. WHILE LOW PRESSURE BECOMES ANCHORED OVER
NORTHEAST CANADA. THIS WILL PRODUCE A PROLONGED PERIOD OF WESTERLY
WINDS OVER LAKE MICHIGAN FROM MID WEEK INTO THE WEEKEND.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 3 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
539 AM CST SUN DEC 4 2011
.UPDATE...
RADAR AND RUC TRENDS INDICATE THE DEFORMATION ZONE PRECIPITATION
HAS FALLEN APART AND MOST SFC OBS INDICATE NO PRECIPITATION IS
OCCURRING. ISOLATED FLURRIES OR VERY LOCALIZED FZDZ MAY BE
OCCURRING IN THE NORTHWEST PART OF THE CWFA BUT MUCH OF THE AREA
NOW LOOKS TO REMAIN DRY.
THE COLD FRONT IS NOW IN THE EASTERN PART OF THE CWFA AND WILL
CLEAR IT BY 14Z AND TAKE WHAT LINGERING RA/SHRA WITH IT. THUS THE
CURRENT TREND OF ENDING ALL PRECIP IN THE EASTERN CWFA BY 15Z
LOOKS ON TARGET.
AS FOR THE CLOUDS...NOT ONE MODEL HAS A HANDLE ON WHAT IS
CURRENTLY GOING ON. THE OPENING IN WESTERN IOWA APPEARS TO BE
SLOWLY SHRINKING BASED ON RECENT SATELLITE TRENDS. THE CAA POURING
INTO THE AREA IS NOT STEEPENING LOW LEVEL LAPSE RATES ALL THAT
MUCH BASED ON RECENT RUC TRENDS. EXTRAPOLATION OF THE POCKET OF
CLEAR SKIES IN WESTERN IOWA SUGGESTS THAT IT WOULD REMAIN WEST OF
THE CWFA DURING THE DAY.
TEMPERATURE WISE...HIGH TEMPERATURES IN THE FAR EASTERN CWFA WILL
OCCUR OVER THE NEXT 1-2 HRS AND THEN SLOWLY FALL THE REMAINDER OF
THE DAY. LOW TEMPERATURES THIS MORNING WILL BE RIGHT AROUND THE
14-15Z TIME FRAME.
AN UPDATE TO THE OVERALL FCST FOR TODAY WILL BE AVAILABLE SHORTLY.
..08..
&&
.AVIATION...
NOT ONE MODEL IS CURRENTLY HANDLING THE CLOUD COVER ACROSS THE
MIDWEST. CIGS BLO 1KFT AGL WILL SLOWLY RISE AND ACHIEVE 1KFT CIGS
15Z-18Z. THE HOLE OF VFR TO UNLIMITED CIGS IN WESTERN IOWA PER
SATELLITE IS A CONCERN BUT RECENT TRENDS SUGGEST THIS HOLE IS
FILLING. AFT 18Z CIGS WILL CONTINUE TO SLOWLY RISE BUT SHOULD
REMAIN IN THE 1-2KFT AGL RANGE. AFT 02Z/05 CIGS AT ALL TAF SITES
SHOULD CLIMB TO 2-3KFT AGL. VSBYS SHOULD REMAIN VFR THROUGH 12Z/05.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
736 AM EST SUN DEC 4 2011
.SYNOPSIS...
RAIN CHANCES WILL BE ON THE INCREASE FOR THE UPPER OHIO VALLEY
REGION AS A COLD FRONT MOVES TOWARD...AND THEN ACROSS THE AREA
EARLY THIS WEEK. COLDER WEATHER WILL RETURN BY MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MADE MINIMAL ALTERATIONS TO TEMPERATURE, CLOUDS, AND WIND BASED ON
RECENT SURFACE DATA AND HRRR MODEL OUTPUT. CONTINUE TO EXPECT SOME
INCREASE IN CLOUDS WEST TO EAST TOWARD AFTERNOON, AS HIGH PRESSURE
EXITS TO THE COAST.
LOW PRESSURE CROSSING THE GREAT LAKES WILL DRAG A COLD FRONT
TOWARD THE PBZ AREA BY TONIGHT...AND RAIN CHANCES WILL DEVELOP FOR
THE WESTERN TIER OF COUNTIES AS THE AFTERNOON PROGRESSES.
WITH WARM ADVECTION UNDER SOUTHERLY FLOW...TODAYS HIGHS ARE
FORECAST APPROXIMATELY 10 DEGREES ABOVE NORMAL USING GFS MOS
GUIDANCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
MODELS IN GENERAL AGREEMENT IN SLOWING EASTWARD PROGRESS OF THE
FRONT...WITH ONLY LOW...OR NO CHANCE OF RAIN FOR WV/MD/ AND MUCH
OF PA WELL INTO MONDAY. CROSSING SHORTWAVE SHOULD DRAG THE FRONT
ACROSS MOST OF THE AREA ON TUESDAY...AND POPS WERE INCREASED TO
CATEGORICAL NUMBERS FOR THE FINAL ADVANCE AND PASSAGE OF THE
BOUNDARY. PROGGED PRECIP AMOUNTS HAVE FALLEN AND DO NOT EXPECT
THOSE TOTALS TO EXCEED THE INCH TO INCH AND A HALF RANGE.
TEMPERATURES THROUGH TUESDAY WERE FORECAST ABOVE THE NORMALS USING
A BLEND OF PERSISTENCE AND GFS MOS. PRECIP CHANCES WERE MAINTAINED
THROUGH WEDNESDAY AS UPPER TROUGH IS FORECAST TO DEVELOP ACROSS
THE GREAT LAKES...WITH SNOW SHOWERS INCLUDED IN THE COOLER AIR
UNDER THAT FEATURE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
NOT MUCH RUN-TO-RUN CONSISTENCY WITH MODELS IN THE LAST DAY. 00Z GFS
PUSHED FRONT OUT TO SEA BY THURSDAY MORNING...THEN THE 12Z GFS
BRINGS A HUGE LOW UP THE EAST COAST. 00Z ECMWF HANGS THE FRONT UP
ALONG THE COASTLINE...WITH THE 12Z ECMWF SLIGHTLY FARTHER OFFSHORE.
00Z CANADIAN/UKMET SUPPORT THE IDEA OF A BIG LOW DEVELOPING ALONG
THE FRONT...BUT HAVE 24-HOUR DIFFERENCES IN THE TIMING. WITH VARYING
SOLUTIONS...WILL STICK CLOSE TO HPC SOLUTION...WHICH BLENDS
GFS/ECMWF ENSEMBLES...WHICH QUICKLY MOVES THE FRONT OFFSHORE. NEXT
FRONT WILL CROSS THE GREAT LAKES FRIDAY INTO SATURDAY...AGAIN WITH
VARYING SOLUTIONS AS TO THE INTENSITY. WILL GO WITH CHANCE POPS
DURING THIS TIME PERIOD. TEMPS WILL BE ABOUT 5 DEGREES BELOW NORMAL
THROUGHOUT THE EXTENDED FORECAST.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
VFR TO CONTINUE INTO TONIGHT, ALTHOUGH RAIN SHOWERS MAY AFFECT
KZZV LATE TONIGHT. EXPECT SOUTHERLY WINDS TO INCREASE LATE THIS
MORNING WITH GUSTS TO 20 KTS THIS AFTERNOON.
OUTLOOK...MONDAY THROUGH THURSDAY...
FRONT WILL STALL OUT ALONG WESTERN BORDER OF THE FORECAST AREA
INTO MONDAY. THIS MAY LIMIT RESTRICTIONS IN SHOWERS DURING THIS TIME
PERIOD TO KFKL AND KZZV. THE FRONT WILL AFFECT ALL TERMINALS BY
MONDAY NIGHT, BRINGING RESTRICTIONS IN SHOWERS. THE FRONT WILL
REMAIN ACROSS THE AREA UNTIL AT LEAST TUESDAY NIGHT. MODELS THEN
DIVERGE...WITH LITTLE CONFIDENCE IN WHETHER THE FRONT WILL REMAIN
OVER THE AREA OR PUSH OFF TO THE EAST.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
515 AM CST SUN DEC 4 2011
.DISCUSSION.../ISSUED AT 311 AM CST/
LIGHT SNOW WHICH AFFECTED PORTIONS OF OUR AREA ON SATURDAY HAS
PUSHED INTO CENTRAL MINNESOTA AND CENTRAL IOWA VERY EARLY THIS
MORNING. BEHIND THE EXITING SYSTEM...A BROAD AREA OF STRATUS HAS
DEVELOPED ACROSS THE EASTERN DAKOTAS INTO EASTERN NEBRASKA...THOUGH
MODELS NOT PICKING UP ON THIS AT ALL. 06Z RUC 925 MB RH TIME SECTION
HINTING AT IT...AND HAS IT PULLING EASTWARD THROUGH THE
MORNING...EXITING OVER OUR FAR EAST BY 18Z. OTHERWISE...A RELATIVELY
QUIET DAY IN STORE...WITH CLOUDS INCREASING IN OUR WEST IN THE
AFTERNOON AS A WEAK SHORTWAVE DROPS SOUTHWARD ON A NORTHWESTERLY
UPPER LEVEL FLOW. NOT MUCH IN THE WAY OF DYNAMICS WITH THIS
FEATURE...BUT COULD SPIT OUT SOME VERY LIGHT SNOW IN OUR WEST BY
LATE THIS AFTERNOON INTO TONIGHT. TEMPERATURES A BIT TRICKY
TODAY IN BETWEEN CLOUD COVER...THOUGH WHAT IS MORE CERTAIN IS THAT
READINGS WILL NOT WARM A WHOLE LOT OVER SNOW COVERED AREAS...WITH
HIGHS GENERALLY IN THE MID 20S THROUGH NORTHWESTERN IOWA AND
PORTIONS OF SOUTHWESTERN MINNESOTA. TO THE WEST...WITH MORE SUN AND
BETTER MIXING IN A TRANSITIONING SOUTHWESTERLY LOW LEVEL
FLOW...HIGHS WILL REACH THE MID 30S ACROSS THE MUCH OF THE JAMES
RIVER VALLEY INTO SOUTH CENTRAL SOUTH DAKOTA.
WINDS WILL BECOME NORTHWESTERLY AND PICK UP FROM WEST TO EAST
TONIGHT IN A TIGHTENING GRADIENT AND COLD AIR ADVECTION BEHIND THE
EXITING SHORTWAVE AND SURFACE LOW/ASSOCIATED FRONTAL BOUNDARY. THE
WINDS AND CLOUD COVER WILL KEEP OVERNIGHT LOWS SOMEWHAT IN
CHECK...THOUGH WILL STILL DROP INTO THE TEENS...EXCEPT SINGLE DIGITS
OVER SNOW COVER.
COLDER AIR WILL CONTINUE TO FILTER INTO THE REGION ON MONDAY WITH A
SURFACE HIGH BUILDING INTO THE REGION. TEMPERATURES WILL NOT RISE
MUCH FROM EARLY MORNING LOWS...WITH HIGHS ONLY IN THE UPPER TEENS TO
LOWER 20S. SOUTHERLY FLOW RETURNS TO THE REGION ON TUESDAY BEHIND
THE EXITING HIGH...AND TEMPERATURES TRY TO WARM A BIT IN THE
WEST...INTO THE MID AND UPPER 20S...WHILE READINGS OVER SNOW COVERED
AREAS MAY ACTUALLY BE A LITTLE COOLER THAN MONDAYS HIGHS WITH LESS
MIXING...REMAINING ONLY IN THE UPPER TEENS.
EVEN WARMER ON WEDNESDAY AHEAD OF THE NEXT ARCTIC SURGE WHICH WILL
DIVE SOUTHWARD ON WEDNESDAY NIGHT AND THURSDAY. COULD GET A LITTLE
SNOW ALONG THE LEADING EDGE OF THIS SURGE/FRONTAL GRADIENT DURING
THAT TIME FRAME...THOUGH ANY SNOW SHOULD BE LIGHT. HIGHS ON
WEDNESDAY WILL BE IN THE UPPER 20S TO MID 30S...THEN DROP BACK TO
THE LOWER TO MID 20S ON THURSDAY. FRIDAY LOOKS TO BE THE COLDEST DAY
OF THE WEEK...WITH HIGHS MID TEENS TO AROUND 20...FOLLOWED BY SOME
WARMING ON SATURDAY. LOOKS TO REMAIN DRY BOTH DAYS.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
LARGE AREA OF STRATUS FROM THE JAMES RIVER EASTWARD AT SUNRISE WILL
CONTINUE MOVING EAST AND DISSIPATING ON THE WEST EDGE THROUGH MID
MORNING. CEILINGS ARE MVFR WITH NO VISIBILITY RESTRICTIONS IN THIS
AREA...AND CLOUDS CHOULD BECOME SCATTERED AT ALL TAF SITES BY 16Z.
LIGHT NORTHWEST SURFACE WINDS AT 12Z WILL BECOME SOUTHERLY AT 5 TO
10 KTS THIS AFTERNOON BEFORE SWITCHING BACK TO THE NORTH OR
NORTHWEST AT 5 TO 10 KTS THIS EVENING BEHIND A LOW PRESSURE SYSTEM
THAT WILL BE MOVING THROUGH THE WESTERN AND CENTRAL DAKOTAS. THERE
WILL BE A CHANCE OF LIGHT SNOW MAKING IT AS FAR EAST AS KHON
OVERNIGHT BEHIND THE LOW. /MG
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
603 AM CST SUN DEC 4 2011
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.UPDATED...CONCERNING HEADLINES.
AVAILABLE REPORTS IN THE ADVISORY AREA SO FAR THIS EVENING RANGE
UP TO 2 INCHES. IR LOOP SHOWS BEST ENHANCEMENT HAS QUICKLY SHIFTED
NORTHEASTWARD INTO UPPER MICHIGAN. RADAR AND OBS ACROSS THE REGION
INDICATE THE RAIN SNOW LINE EXTENDS FROM NORTHWEST IOWA TO RST TO
STE TO JUST SOUTH OF IMT. A SURFACE LOW WAS OVER SOUTHERN IOWA
EARLY THIS EVENING AND WILL BE ENTERING SOUTHWEST WISCONSIN LATE
THIS EVENING AND NEARLY TRACKING ALONG THE RAIN SNOW LINE
OVERNIGHT. A LARGE AREA OF RAIN WAS IN THE WARM SECTOR OF THE LOW
OVER IOWA AND SOUTHERN WISCONSIN MOVING TOWARD EASTERN WISCONSIN.
PARTS OF EASTERN WISCONSIN MAY SEE UP TO AN ADDITIONAL INCH OF
RAIN OVERNIGHT.
BUT BACK TO THE ADVISORY...BEST SNOW GROWTH REGION WAS OVER
NORTHWEST WISCONSIN AND MAY INCLUDE WESTERN PORTIONS OF ONEIDA AND
VILAS COUNTIES. THIS SNOW GROWTH REGION IS PROGGED TO SAG INTO
NORTH CENTRAL WISCONSIN OVERNIGHT AS THE H8 LOW AND SURFACE LOW
TRACKS OVER. NOT OUT OF THE QUESTION A WARNING MAY BE NEEDED AS
THESE MORE FAVORABLE DYNAMICS PLAY A ROLE...BUT FOR NOW WILL
CONTINUE THE HIGH END ADVISORY.
TDH
&&
.PREV DISCUSSION...ISSUED AT 505 PM CST SAT DEC 3 2011...
SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DEVELOPING
LOW PRESSURE SYSTEM MOVING NORTHEAST OVER SOUTH-CENTRAL KANSAS JUST
AHEAD OF A SHORTWAVE TROUGH. ATTACHED TO THE SURFACE LOW TO THE
NORTHEAST RUNS A COLD FRONT OVER CENTRAL IOWA INTO NORTHWEST
WISCONSIN. FIRST BATCH OF PRECIP IS RIDING ALONG THE 850MB
BAROCLINIC ZONE OVER THE SOUTHEASTERN HALF OF WISCONSIN THOUGH SOME
BREAKS ARE SPREADING OVER EASTERN IOWA AND NORTHERN ILLINOIS...THAT
MAY SPELL A BREAK IN THE PRECIP FOR A BRIEF PERIOD LATE THIS
AFTERNOON OVER E-C WISCONSIN. THE MAIN AXIS OF PRECIP...HOWEVER...
EXISTS JUST TO THE EAST OF THE SURFACE LOW ON THE NOSE OF A 60 KT
LLJ AND UPPER DIVERGENT AREA WITHIN THE COUPLED JET. SOME HIGHER
REFLECTIVITIES ARE ALSO DEVELOPING OVER WESTERN WISCONSIN WITHIN A
STRENGTHENING FGEN ZONE...SO WILL JUST START THE WINTER HEADLINES
WITH THE AFTERNOON PACKAGE. AS THE LOW TRACKS NORTHEAST OVER THE
NEXT 24 HOURS...THE OBVIOUS CONCERNS ARE SNOW AMOUNTS AND
HEADLINES.
TONIGHT...FOLLOWED A SREF/GFS BLEND TONIGHT...WHICH SPLITS THE
DIFFERENCE BETWEEN THE STRONGER NAM AND WEAKER ECMWF WHILE KEEPING
THE CONSENSUS TRACK. LOW PRESSURE OVER THE CENTRAL PLAINS WILL
RAPIDLY MOVE NE TOWARDS THE MID-MISSISSIPPI VALLEY THIS
EVENING...AND NORTHERN LAKE MICHIGAN BY 12Z SUNDAY. AHEAD OF THE
LOW...A BEEFY LLJ WILL SHIFT INTO SOUTHERN WISCONSIN THIS
EVENING...THEREBY INCREASING CONVERGENCE ALONG THE STALLED
BAROCLINIC ZONE STRETCHING ACROSS THE STATE...AND 850-700MB FGEN IN
THE PROCESS. COMBINED WITH STRONG QG FORCING FROM SHORTWAVE ENERGY
AND A WIDE OPEN GULF (PWATS 150-200 PCT OF NORMAL)...THE BEEFY SLUG
OF PRECIP OVER THE PLAINS WILL HAVE NO TROUBLE SPREADING ACROSS THE
STATE THIS EVENING. PTYPE REMAINS PROBLEMATIC AS THE 12Z MODEL RUNS
HAVE TRENDED SLIGHTLY WARMER WITH THE THERMAL PROFILE AS THE LOW
PUSHES WARMER AIR ALOFT SLIGHTLY FARTHER NORTH THAN PREVIOUS RUNS.
THIS WILL PLACE THE RAIN-SNOW MIX AREA FROM WOOD COUNTY TO NORTHERN
OCONTO AND MARINETTE. NORTH OF THE RAIN-SNOW LINE SHOULD RESIDE THE
AXIS OF HEAVIEST SNOWFALL...WHICH LINES UP WITH THE EXTRAPOLATED
SOUTHERN EDGE OF THE COMMA HEAD FROM APPROX MERRILL TO CRANDON.
WITH SLIGHTLY COLDER AIR IN PLACE COMPARED TO THE FIRST SNOW STORM IN
NOVEMBER...SNOW RATIOS WILL RUN BETWEEN 10-14:1 OVER THIS AREA
ACCORDING TO THE COBB SNOWFALL ALGORITHM. WITH QPFS AROUND 0.4 TO
0.5 INCHES...THIS AMOUNTS TO A GOOD 4-6 INCH SWATH OF SNOW TONIGHT
(5 TO 7 INCHES OVERALL)...THOUGH THE BULK OF THE PRECIP WILL LIKELY FALL
THIS EVENING. THE FOX VALLEY AND LAKESHORE WILL RESIDE WITHIN THE
WARM SECTOR OF THE STORM...WHICH MEANS MOSTLY RAIN TONIGHT...THOUGH
SOME SNOW MAY MIX IN LATE. ENTERTAINED SOME THOUGHTS OF UPGRADING TO
A WARNING GIVEN THE HEAVY SNOW OBS UPSTREAM...BUT GIVEN THE
RELATIVELY LOW IMPACT OF THE SNOW (DURING THE NIGHT ON A
WEEKEND)...WILL STICK WITH ADVISORY HEADLINES. ALSO THOUGHT ABOUT
TRIMMING THE ADVISORY TO THE NW BY A ROW OF COUNTIES...BUT
COORDINATION WITH SURROUNDING OFFICES YIELDED A RELUCTANCE...DUE TO
THE SLOPPINESS OF THE MIX AND POTENTIAL FOR FREEZING DRIZZLE. AS A
RESULT...WILL KEEP CURRENT HEADLINES AS THEY CURRENTLY STAND BUT
STRESS THE HEAVY SNOWFALL RATES ARRIVING THIS EVENING.
SUNDAY...THE LOW PRESSURE WILL QUICKLY EXIT TO SOUTHEAST ONTARIO BY
18Z SUNDAY BUT WILL HAVE THE BACK EDGE OF THE COMMA HEAD SHIFTING NE
OVER N-C AND FAR NORTHEAST WISCONSIN. SOME MID-LEVEL FGEN WILL
LINGER WHICH WILL RESULT IN ANOTHER HALF INCH TO AN INCH OVER N-C
WISCONSIN EARLY IN THE MORNING. BUT OTHERWISE...SNOW WILL BE
TAPERING DOWN TO JUST FLURRIES IN THE MORNING...WHILE COLDER AIR
FILTERS ACROSS THE REGION. LOW LEVEL TROUGHINESS AND CYCLONIC FLOW
WILL HANG AROUND FOR MUCH OF THE DAY...SO NOT ANTICIPATING MUCH
CLEARING TOMORROW. HIGHS MAINLY IN THE LOW TO MIDDLE 30S.
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...THE MAIN FCST
CONCERNS WILL BE MINOR LAKE EFFECT SNOW POTENTIAL OVER NORTHERN
WI EARLY IN THE PERIOD...THEN THE POTENTIAL FOR SNOW AND MUCH
COLDER TEMPERATURES WITH AN ARCTIC FRONTAL PASSAGE LATE NEXT
WEEK.
A STRONG...HIGH AMPLITUDE RIDGE WILL COVER THE EASTERN PACIFIC...
WESTERN CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...
WITH A POSITIVELY-TILTED UPPER TROF EXTENDING FROM CENTRAL CANADA
INTO THE SOUTHWEST UNITED STATES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON TUESDAY...WITH LITTLE IMPACT ON OUR WEATHER. SHORT-WAVE
ENERGY WILL TOP THE WESTERN RIDGE EARLY NEXT WEEK...THEN EVENTUALLY
HELP TO CARVE A BROAD TROF OVER THE CENTRAL U.S. BY THU/FRI. A
SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN WI LATE IN THE WEEK...
WITH H8 TEMPS PLUMMETING TO AROUND -20 C. THIS WILL LEAD TO OUR
COLDEST TEMPERATURES SO FAR THIS SEASON.
A LARGE RIDGE OF HIGH PRESSURE WILL BE CENTERED OVER THE NORTHERN
ROCKIES AND NORTHERN PLAINS SUN NGT INTO MON...WITH COLD NORTH
FLOW RESULTING IN SCT LAKE-EFFECT SNOW SHOWERS OVER MAINLY NC WI.
THE SNOW SHOWERS MAY LINGER INTO MONDAY NIGHT...BUT SHOULD COME TO
AN END ON TUESDAY AS THE RIDGE AXIS PUSHES ACROSS WI.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING SOMETIME DURING
THE THU/FRI TIME FRAME. DURING THIS PERIOD...LLVL FLOW IS EXPECTED
TO BE TOO WESTERLY FOR LK-EFFECT. THE ECMWF AND A FEW OF THE GFS
ENSEMBLE MEMBERS SUGGEST THAT A SFC WAVE WILL DEVELOP ALONG THE
ARCTIC BOUNDARY LATE IN THE WEEK...AS THE RRQ OF A STRONG UPPER
LEVEL JET PULLS THROUGH THE REGION. IF THIS PLAYS OUT...WE COULD
BRING SEE SEVERAL INCHES OF POWDERY SNOW SOMETIME DURING THE
THURSDAY NIGHT TO SATURDAY PERIOD. FOR NOW...WILL FOLLOW THE
CONCENSUS OF AREA OFFICES...AND JUST MENTION SMALL POPS ACROSS OUR
SOUTHERN AND EASTERN COUNTIES ON THU NGT/FRI. THERE IS A HIGHER
DEGREE OF CONFIDENCE IN A TREND TOWARD MUCH COLDER TEMPERATURES
LATE IN THE WEEK...ALTHOUGH THE NEW ECMWF IS SLOWER WITH THE
TIMING OF THE ARCTIC BOUNDARY. SUBSEQUENT FCSTS SHOULD BE BETTER
ABLE TO PINPOINT THE FRONTAL TIMING AND SNOWFALL POTENTIAL LATE
NEXT WEEK.
&&
.AVIATION...SNOW IS ENDING BUT IFR CIGS WILL LIKELY REMAIN OVER
MOST OF THE REGION THROUGH EARLY AFTERNOON AND THEN MVFR IN MOST
PLACES.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
548 AM CST SUN DEC 4 2011
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
324 AM CST SUN DEC 4 2011
MAIN FORECAST CONCERN NOW THAT THE PRECIPITATION IS
EXITING/DIMINISHING IS WHEN CLOUDS WILL CLEAR.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING STILL OVER THE EAST PACIFIC AND ALONG THE EAST COAST
OF THE U.S....AND TROUGHING IN-BETWEEN FROM HUDSON BAY SOUTHWEST
INTO ARIZONA. IMPORTANT FEATURES TO NOTE INCLUDE A SHORTWAVE NEAR
EAU CLAIRE WI ON THE EAST SIDE OF THE UPPER TROUGH...AND TWO
SHORTWAVES OVER MONTANA ON THE BACK SIDE OF THE UPPER TROUGH. THE
FORMER SHORTWAVE IN CONJUNCTION WITH PLENTIFUL MOISTURE AND LOW TO
MID-LEVEL FRONTOGENESIS BROUGHT THE WIDESPREAD PRECIPITATION TO THE
AREA LAST NIGHT. DRY SLOT NOTED IN WATER VAPOR COMBINED NOW WITH THE
SHORTWAVE MOVED THROUGH...RESULTING IN SOME SUBSIDENCE...HAS ALLOWED
PRECIPITATION TO REALLY DIMINISH DURING THE PAST 4-6 HOURS. IT
APPEARS MODELS YESTERDAY MAY HAVE OVERDONE THE LOW LEVEL ISENTROPIC
LIFT FOR THE CURRENT EARLY MORNING HOURS... GIVEN THAT THEY NOW SHOW
NO ISENTROPIC LIFT AND SEEING THE PRECIPITATION DIMINISH ON RADAR.
THEREFORE...THE CONCERN ABOUT THE DRY SLOT CLEARING OUT ICE AND
RESULTING IN FREEZING PRECIPITATION IS NOT AS GREAT. IN ADDITION...
SURFACE TEMPERATURES HAVE STRUGGLED TO FALL BELOW FREEZING WHERE IR
CLOUD TOP TEMPERATURES INDICATE ICE HAS BEEN LOST. REGARDING THE
SURFACE...SEA LEVEL PRESSURE ANALYSIS SHOWS A 1008MB LOW NEAR
MANITOWOC WI. PLENTY OF CLOUDS EXTEND WEST FROM THE LOW...BACK
INTO THE EASTERN DAKOTAS. UPSTREAM...ANOTHER BUT MUCH WEAKER SURFACE
LOW IS NOTED NEAR WILLISTON ASSOCIATED WITH ONE OF THE MONTANA
SHORTWAVES.
TODAY AND TONIGHT...A SHORTWAVE IN EASTERN MONTANA IS PROGGED TO
MOVE INTO SOUTH DAKOTA TODAY AND INTO NORTHWEST WISCONSIN TONIGHT.
THE TRACK OF THE SHORTWAVE SUGGESTS ALL OF THE FORCING WILL STAY
NORTH AND WEST OF THE AREA. THIS IS CONFIRMED TOO BY QG PLOTS. IN
ADDITION...IT APPEARS MUCH OF THE CLOUD COVER ASSOCIATED WITH THE
SHORTWAVE WILL STAY TO THE NORTHWEST. SO THIS LEAVES THE CURRENT
CLOUD COVER AND SYSTEM GOING THROUGH THE MAIN CONCERN. WITH STRATUS
EXTENDING SO FAR WEST...GRADUAL SUBSIDENCE OCCURRING TODAY IN THE
WAKE OF THE SYSTEM AND THE LOW SUN ANGLE...THINKING A VERY
PESSIMISTIC TREND MIGHT BE THE WAY TO GO. LIKE THE 04.00Z NAM
INDICATING THE STRATUS STAYS IN PUT ACROSS THE AREA TODAY WITH ONLY
SLOW CLEARING TONIGHT FOR WESTERN AREAS. CONCERNED THAT EVEN THE NAM
MIGHT BE TOO FAST TONIGHT AS THE 900-950MB WINDS TURN FROM THE
NORTHWEST TO NORTH. COMBINED WITH THE RECENT MOISTURE...CLOUDS MAY
ACTUALLY LOWER IN CEILING HEIGHT VERSUS CLEARING. LAST CONCERN IS
PRECIPITATION...BOTH THIS MORNING AND POSSIBLY OUT OF THE STRATUS
DECK TONIGHT. GIVEN DIMINISHING RADAR RETURNS AND DRY FORECASTS
INDICATED BY THE 04.00Z NAM/GFS/ECMWF FOR 12-18Z TODAY...HAVE REALLY
DRIED OUT THIS MORNING. IN FACT...THERE MAY NOT BE MUCH GOING ON
AFTER 12Z. WITH PRECIPITATION RAPIDLY DIMINISHING...WILL CANCEL THE
ADVISORY HERE AT 4 AM. TONIGHT...THE 04.00Z NAM/GFS SHOW SOME LIGHT
QPF OVER THE NORTH HALF OF WISCONSIN. APPEARS TO RESULT FROM LOW
LEVEL CONVERGENCE...ASSOCIATED WITH SURFACE TROUGHING LINGERING BACK
FROM THE CURRENT AREA OF LOW PRESSURE NEAR GRB. HAVE ADDED A 20
PERCENT CHANCE OF SNOW INTO THE FORECAST TO ACCOUNT FOR THIS
POSSIBILITY. OTHERWISE...TEMPERATURES LOOK LIKE THEY SHOULD STRUGGLE
TO RISE TODAY WITH 850MB TEMPS FALLING TO AT LEAST -6 TO -8C AND
CLOUDS STAYING PUT. MAYBE A 1 OR 3 DEGREE F RISE IS POSSIBLE FROM
THE 6 AM TEMPERATURE. WITH MORE CLOUDS ANTICIPATED TONIGHT...BROUGHT
LOW TEMPERATURES UP A FEW DEGREES...ESPECIALLY ALONG AND EAST OF THE
MISSISSIPPI RIVER WHERE CLOUDS ARE MORE CERTAIN. WHERE CLOUDS CLEAR
OUT...TEMPERATURES COULD FALL INTO THE UPPER SINGLE DIGITS.
MONDAY THROUGH TUESDAY NIGHT...BIG STORY/CONCERN HERE IS FORECASTING
WHEN THE STRATUS WILL DISSIPATE AND ANY POTENTIAL PRECIPITATION OUT
OF IT. UPPER TROUGH SITUATED OVER THE NORTHERN PLAINS IS FORECAST TO
MARCH SOUTHEAST DURING THIS PERIOD...IN RESPONSE TO A POWERFUL UPPER
TROUGH DIGGING FORMING OVER CENTRAL CANADA. NORTH TO NORTHEAST LOW
LEVEL FLOW IS LIKELY MONDAY INTO MONDAY NIGHT WITH HIGH PRESSURE
BUILDING INTO THE NORTHERN PLAINS. THIS FLOW SHOULD DO A DECENT JOB
IN HOLDING IN THE STRATUS BELOW THE SUBSIDENCE INVERSION...UNTIL
MAYBE LATE MONDAY NIGHT WHEN THERE IS SUGGESTION THE FLOW BACKS
NORTHWEST TO BRING IN SOME DRIER LOW LEVEL AIR. IN ADDITION...THAT
TROUGH MENTIONED IN THE TONIGHT DISCUSSION IS PROGGED TO DROP
SOUTHWEST DUE TO THE LOW LEVEL FLOW. CONVERGENCE ALONG THIS TROUGH
COULD RESULT IN SOME FLURRY ACTIVITY AND HAVE ADDED IT TO THE
FORECAST. 04.00Z CANADIAN MODEL IS EVEN MORE AGGRESSIVE AND SHOWING
A FEW HUNDREDTHS. IF OTHER MODELS...SUCH AS THE NAM/GFS START TO
SHOW THIS IN LATER RUNS...MAY NEED TO HAVE SOME HIGHER CHANCES
ADDED. BETTER POTENTIAL FOR CLEARING EXISTS TUESDAY AS THE SURFACE
RIDGE MOVES IN AT THE SAME TIME WITH DAYTIME HEATING...SO INDICATED
CLEARING STARTING HERE. UPPER RIDGING THEN BUILDS OVER THE AREA FOR
TUESDAY NIGHT AHEAD OF THE POWERFUL UPPER TROUGH...MAINTAINING DRY
CONDITIONS WITH GENERALLY MOSTLY CLEAR SKIES. FOR TEMPERATURES...
LOOK FOR A COOLING TREND AS THE UPPER TROUGH MOVES IN. DID RAISE LOW
TEMPERATURES UP MONDAY NIGHT IN THE CLOUDY SKY AREA...CLOSER TO THE
2 METER NAM12 GUIDANCE. OTHERWISE...A BLEND OF GUIDANCE SEEMED
REASONABLE.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
324 AM CST SUN DEC 4 2011
AFTER WHAT WAS SOME UNCERTAINTY IN THE LONG TERM FORECAST...CAUSED
ESPECIALLY BY THE 03.12Z ECMWF SUGGESTING A POSSIBLE ADVISORY-TYPE
SNOW MOVING THROUGH FRIDAY/FRIDAY NIGHT...ALL MODELS HAVE COME BACK
INTO GREAT AGREEMENT ON THE UPPER AND SURFACE PATTERNS THROUGHOUT
THE LONG TERM. IN FACT...THEY LOOK A LOT LIKE WHAT WAS SHOWN BY THE
03.00Z CYCLE. SO FOR NOW WILL CONSIDER THE 03.12Z ECMWF AN ODD
OUTLIER. A WEST-NORTHWEST FLOW UPPER PATTERN BEGINS THE LONG
TERM...ON THE SOUTH SIDE OF THE POWERFUL TROUGH DROPPING INTO
SOUTHERN CANADA. A COLD FRONT LOOKS TO SLIDE THROUGH THE FORECAST
AREA ON WEDNESDAY...ENDING A BRIEF WARM SURGE ALOFT CAUSED BY THE
UPPER RIDGE. THEN FOR WEDNESDAY NIGHT AND THURSDAY...A SHORTWAVE
TROUGH IS FORECAST TO DIG DOWN THE WEST SIDE OF THE CANADA UPPER
TROUGH...CAUSING AN UPPER JET TO STRENGTHEN DOWNSTREAM OVER NORTHERN
WISCONSIN. RIGHT ENTRANCE REGION FORCING OF THIS JET SHOULD INDUCE
SOME MID-LEVEL FRONTOGENESIS...AND COMBINED WITH A LITTLE MOISTURE
MAY PRODUCE A BAND OF LIGHT SNOW OVER FAR SOUTHERN SECTION THURSDAY
NIGHT. INCLUDED A 20 PERCENT CHANCE FOR THIS. BIGGER IMPACT IS ON
FRIDAY WHEN THE SHORTWAVE TROUGH MOVES ACROSS...CAUSING 850MB TEMPS
TO TANK FROM -9 TO -13C ON THURSDAY TO AROUND -20C ON FRIDAY.
NEEDLESS TO SAY...BELOW NORMAL TEMPERATURES LIKELY. A DRY AND SLOW
WARMING TREND SHOULD THEN ENSUE HEADING INTO THE WEEKEND IN RESPONSE
TO THE MODELS FORECASTING THE UPPER FLOW BECOMING MORE ZONAL. IN
FACT...THE LATEST 04.00Z ECMWF SUGGESTS HIGHS APPROACHING 40 FOR
NEXT SUNDAY AS A SURGE OF DOWNSLOPED WARMED PACIFIC AIR FLOWS INTO
THE AREA.
&&
.AVIATION...TODAY INTO MONDAY
548 AM CST SUN DEC 4 2011
LOW PRESSURE THAT BROUGHT SNOW AND MVFR/IFR CIGS/VSBYS TO THE TAF
SITE SAT/SAT NIGHT WILL CONTINUE TO MOVE AWAY FROM THE AREA TODAY.
VFR VSBYS WILL PREVAIL ACROSS MN/WI TODAY/TONIGHT AS DRYER BOUNDARY
LAYER AIR SPREADS ACROSS THE AREA ON NORTHWEST WINDS. SUBSIDENCE
BEHIND THE LOW IS ON THE WEAK SIDE AND ANOTHER SHORTWAVE WILL BE
DROPPING SOUTH INTO THE UPPER MIDWEST FOR TONIGHT/MONDAY. WITH
CONSIDERABLE MOISTURE IN THE 925-850MB LAYER LINGERING OVER MN/IA/WI
AND SOME WEAK LIFT FROM THE SHORTWAVE DROPPING INTO THE REGION...
MVFR CLOUD DECKS ARE EXPECTED TO REMAIN OVER THE TAF SITES THRU
TONIGHT AND MONDAY. THERE MAY BE ENOUGH DEPTH OF MOISTURE/CLOUDS AND
WEAK CONVERGENCE/LIFT TO PRODUCE SCT FLURRIES ON MON. THESE NOT
EXPECTED TO HAVE AN IMPACT ON VSBYS MON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
324 AM CST SUN DEC 4 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS DENVER CO
250 PM MST SUN DEC 4 2011
.SHORT TERM...BROAD UPPER TROF COVERS MUCH OF THE WESTERN U.S. WHILE
WATER VAPOR IMAGERY SHOWING NEXT DISTURBANCE DROPPING SOUTH INTO THE
MEAN TROF POSITION OVER UTAH. RUC QG FIELDS SHOWING BEST UPWARD
FORCING OVER WESTERN CO AND WESTERN WYOMING. THE ASSOCIATED COLD
FRONT IS MOVING SOUTH FROM SOUTHERN WYOMING INTO NORTHERN COLORADO
WITH GUSTY NORTHERLY WINDS DEVELOPING BEHIND THE FRONT. CEILINGS ARE
BEGINNING TO LOWER OVER THE FRONT RANGE WITH SOME VERY LIGHT ECHOES
DEVELOPING OVER THE FOOTHILLS. OVERALL...FORECAST IS STILL ON TRACK
WITH MAIN CONCERN SNOW AMOUNTS FOR UPCOMING STORM. SNOW AMOUNTS
EXPECTED TO BE A BIT LOWER THAN THE LAST STORM...AS QG VERTICAL
VELOCITY FIELDS SHOWING THE BEST FORCING ACROSS WESTERN COLORADO
WITH LESSER FORCING OVER NORTHEAST COLORADO AND OVERALL MOISTURE IS
A BIT LOWER. HIGHEST SNOW AMOUNTS WILL BE OVER THE EAST SLOPE FRONT
RANGE FOOTHILLS WITH LESSER AMOUNTS AS YOU MOVE EAST AWAY FROM THE
FOOTHILLS. THERE IS SOME GOOD LOW LEVEL INSTABILITY WITH UPSLOPE UP
TO AROUND 600MB. WILL KEEP THE CURRENT 3-6 SNOWFALL RANGE OVER THE
URBAN CORRIDOR BUT WOULDN`T BE SURPRISED IF AMOUNTS END UP BEING A
BIT LOWER. BIG DROPOFF OF SNOW EAST OF INTERSTATE 25 AND AM
CONCERNED THAT THERE WON`T BE MUCH SNOW OVER EASTERN WELD COUNTY AND
ZONE 45 AND 46 WITH CURRENT ADVISORIES. WILL LEAVE IN PLACE FOR NOW.
FOR THE FOOTHILLS WILL STILL GO WITH 5 TO 10 INCHES. EVEN COLDER
TEMPERATURES FOR TONIGHT AND MONDAY WITH READINGS IN THE SINGLE
DIGITS AND LOWER TEENS FOR THE NEXT 24 HOURS.
.LONG TERM...COULD STILL SEE A FEW FLURRIES OCCURRING SOUTH ON
INTERSTATE 70 AS THE STORM CONTINUES TO MOVE SOUTH AND COLD HIGH
PRESSURE SETTLES IN. TEMPERATURES WILL CONTINUE TO PLUMMET TO BELOW
ZERO ACROSS THE AREA. WILL LIKELY SEE VERY COLD TEMPERATURES IN THE
HIGH MOUNTAIN VALLEYS...DROPPING TO AROUND -20 TO -30 BY EARLY
TUESDAY MORNING.
THE PERSISTENT UPPER TROUGH WILL FINALLY MOVE SOUTHEAST OF THE AREA
WITH A SHORT WAVE UPPER RIDGE MOVING OVERHEAD HOWEVER FLOW ALOFT
WILL STILL BE NORTHERLY. TEMPERATURES WILL WARM SLIGHTLY...BUT HAVE
KEPT TEMPERATURES COOLER THAN GUIDANCE AS THE RECENT COLD AIRMASS
WILL BE HARD TO SCOUR OUT AND THE SNOW ON THE GROUND WILL LIKELY
HAVE AN AFFECT AS WELL. HAVE KEPT HIGHS IN THE TEENS TO UPPER 20S
FOR TUESDAY. ON WEDNESDAY...FLOW ALOFT WILL TURN WESTERLY AS A BROAD
UPPER TROUGH OVER CANADA DROPS SOUTH. THE WEST WINDS WILL HELP
TEMPERATURES WARM DURING THE DAY...THEN A WEAK COLD FRONT WILL DROP
SOUTH DURING THE NIGHT. NO REAL PRECIPITATION EXPECT THAT
NIGHT...HOWEVER IT WILL RESULT IN COOLER TEMPERATURES AND A SLIGHT
CHANCE OF SNOW THURSDAY AS ANOTHER SHORTWAVE TROUGH ROUNDS THE
BOTTOM OF THE LARGER TROUGH.
THE LARGE SCALE PATTERN WILL CONTINUE TO TRANSITION EAST FRIDAY TO
BRING A STRONGER UPPER RIDGE OVER THE ROCKIES BRINGING DRIER WEATHER
AND RELATIVELY WARMER AIR FRIDAY AND SATURDAY. INTRODUCING A SLIGHT
CHANCE OF PRECIPITATION FOR SUNDAY AS MODELS DISAGREEING ON WHETHER
THERE WILL BE ANOTHER TROUGH OR RIDGE OVER THE AREA.
&&
.AVIATION...CEILINGS BEGINNING TO LOWER NORTH OF THE LOCAL TERMINALS
WITH CIGS OF 5000-7000 FEET AGL UPSTREAM OVER FNL AND GXY. THIS WILL
RESULT IN ILS APPROACHES AROUND 23Z AT DEN AND BJC. THE LIGHT SNOW
NOT FAR BEHIND WITH SNOW NOW AT CYS. MORE WIDESPREAD SNOW AT LOCAL
AIRPORTS DEVELOPING BETWEEN 02-3Z AND CONTINUING THROUGH ABOUT 08Z.
THIS WILL BE THE WINDOW OF MOST OF THE ACCUMULATION SNOW. MOST OF
THE SNOW WILL BECOME VERY LIGHT AND JUST FLURRIES DURING THE DAY ON
MONDAY WITH ACCUMULATIONS UNDER AN INCH. STILL TOTAL ACCUMULATIONS
OF 3 TO 6 INCHES...WITH 2-3 AT DIA...3-4 AT APA AND 4 TO 6 AT BJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 11 AM MST MONDAY
FOR THE URBAN CORRIDOR...PALMER DIVIDE AND ADJACENT PLAINS...ZONES
COZ038>041-043-045-046.
WINTER WEATHER ADVISORY UNTIL 11 AM MST MONDAY FOR THE FOOTHILLS AND
SOUTH PARK...ZONES COZ035>037.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....KRIEDERMAN
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
154 PM CST SUN DEC 4 2011
.DISCUSSION...
1125 AM CST
FRONTAL BOUNDARY CONTINUES TO STEADILY PUSH EAST ACROSS THE
CWFA...EXPECTED BY MIDDAY TO PUSH THROUGH NORTHWEST INDIANA.
BEHIND THIS BOUNDARY TEMPERATURES IN MANY LOCATIONS HAVE FALLEN
INTO THE UPPER 30S TO LOWER 40S. EXPECT TEMPERATURES TO REMAIN
NEARLY STEADY THROUGHOUT THE REMAINDER OF THE DAY...THEN SLOWLY
BEGIN TO FALL THIS EVENING. ONE CAVEAT FOR HOW LOW TEMPERATURES
MAY FALL TONIGHT WILL BE THE POSSIBILITY OF ABUNDANT CLOUD COVER.
CURRENT GUIDANCE CONTINUES TO INDICATE THAT SKIES WILL STEADILY
BREAK-UP THIS AFTERNOON AND POSSIBLY TURN SCATTERED TONIGHT.
HOWEVER...LOOKING AT THE CURRENT VISIBLE IMAGERY ACROSS THE ENTIRE
REGION AND MANY LOCATIONS UPSTREAM THIS SCENARIO OF THINNING SKIES
LOOKS TO BE IN JEOPARDY. THUS HAVE CONCERNS ABOUT HOW COLD WE WILL
SEE TEMPERATURES FALL TONIGHT. NONETHELESS 850MB THERMAL TROUGH
CONTINUES TO PIVOT EAST...AND REMAIN OVERHEAD TONIGHT. AIDING IN
TEMPERATURES FALLING INTO THE UPPER 20S TO LOWER 30S TONIGHT WILL
BE THE STEADY COLD AIR ADVECTION WITH NORTHERLY WINDS TURNING
NORHTEASTERLY.
WITH AN INCREASING THERMAL DIFFERENTIAL ACROSS THE RELATIVELY
WARMER MARINE ENVIRONMENT...AND MUCH COOLER AIR ALOFT EXPECT A
NARROW CHANNEL OF LAKE MOISTURE TO FORM FROM THE NORTH/NORTHEAST
WINDS. THIS WILL AID IN THE POSSIBILITY OF LAKE EFFECT
FLURRIES/LGT SN. THEN BECOMING MIXED WITH LGT RA AFTER DAYBREAK
MON. THROWING A POTENTIAL MONKEY WRENCH IN THIS SCENARIO COULD BE
THE DEPTH OF THE FAVORED DENDRITIC GROWTH ZONE AND MOISTURE. VERY
MINIMAL VERTICAL ENERGY MAY LIMIT THIS TO POSSIBLY JUST SOME
DRIZZLE. THIS WILL BE THE FIRST CHALLENGE OF THE EVENING FORECAST.
AS THIS COULD END UP BEING FROZEN DRIZZLE WITH TEMPERATURES
POSSIBLY IN THE LOWER 30S.
BEACHLER
//PREV DISCUSSION...
340 AM CST
HIGHLIGHTS THIS WEEK WILL INCLUDE RAIN COMING TO AN END...POSSIBLE
SN/RASN/RA ACROSS THE SOUTHEAST MONDAY...LES POTENTIAL FOR
LAKE/COOK LATE SUNDAY NIGHT INTO MONDAY...TRANSITIONING SOUTH TO
LAKE/PORTER INDIANA BY TUESDAY...A FEW DAYS OF QUIET...FOLLOWED
BY A LATE CLIPPER AND SNOW POTENTIAL AND FINALLY A BLAST OF COLD
BY NEXT WEEKEND.
THE EARLY MORNING SURFACE MAP SHOWED THE SURFACE LOW THAT HAS
BEEN BRINGING THE WET AND ACTIVE WEATHER TO THE AREA
TODAY...CONTINUING TO LIFTING NORTH THROUGH CENTRAL WISCONSIN.
MEANWHILE AN ATTENDANT COLD FRONT LAY ROUGHLY ACROSS THE
MISSISSIPPI RIVER...SOUTHWEST NEARLY TO ST LOUIS. THIS FRONT WILL
CONTINUE TO SLOWLY SWEEP FROM WEST TO EAST THIS MORNING EVENTUALLY
PUSHING ITSELF AND THE PRECIP EAST. THE MOST WIDE SPREAD ECHOES HAVE
PUSHED EAST AND ONLY A FEW SCATTERED SHOWERS ARE LOCATED WITH THE
ACTUAL FRONT. ACROSS EAST CENTRAL IOWA...TEMPERATURES HAVE
DROPPED ENOUGH THAT -SN WAS REPORTED...BUT CLOUD TOPS HAVE WARMED
ENOUGH AND ARE WARMER THAN -10C. THIS MEANS THAT THERE IS NO
LONGER ICE INTRODUCTION INTO THE SATURATED LAYERS BELOW...AND A
FEW LOCATIONS REPORTED U.P. AND OR FZDZ. FOR OUR AREA...AFTER THE
FRONT MOVES THROUGH...LOWER LEVEL MOISTURE WILL REMAIN BUT
PROFILES ARE STILL INDICATIVE OF LIQUID PRECIP AND SURFACE TEMPS
WILL REMAIN ABOVE FREEZING.
THE HRRR AND RUC BOTH HAVE A GOOD HANDLE ON THE WESTERN EDGE OF THE
PRECIP AND FRONTAL LOCATION...AND MOST OF IT SHOULD CLEAR THE
ROCKFORD CORRIDOR NEAR SUNRISE...WITH CHICAGO AND EAST JUST A FEW
HOURS BEYOND. WHILE LOWER LEVEL RH WILL REMAIN PREVALENT WITH AND
SHORTLY BEYOND FROPA...MOISTURE ABOVE -10C WILL DISAPPEAR AND
THERE MAY BE SOME LINGERING DZ INTO THE EARLY MORNING HOURS. THE
BIG PUSH OF COLDER AIR ISNT EXPECTED UNTIL LATER THIS EVENING AND
TEMPERATURES WILL REMAIN ABOVE FREEZING...SO NO CONCERN OVER ANY
OTHER PRECIP TYPES THIS MORNING. HIGH TEMPS WILL GENERALLY BE
SEEN EARLY TODAY...AND SLOWLY FALL THROUGH THE DAY. WINDS WILL
ABATE AS HIGH PRESSURE AND A PERIOD OF DRY...SLOWLY MOVE IN.
THE MAIN UPPER LEVEL TROUGHING THAT STRETCHES FROM ROUGHLY
SASKATCHEWAN...SOUTHWEST THROUGH THE FOUR CORNERS REGION WILL NOT
HAVE MUCH REASON TO MOVE UNTIL THE START OF THE WORKWEEK. PRESENT
SHORTWAVE SEEN ON WATER VAPOR IMAGERY ROUNDING THE BASE OF THE
TROUGH...ACROSS SOUTHERN ARIZONA...WILL DAMPEN SOME AS IT
GETS EJECTED ON THE EASTERN FLANK TODAY AND TONIGHT. AS IT DOES
THIS...IT WILL HELP TO AMPLIFY AN INVERTED TROUGH THAT WILL NOSE
ITS WAY TOWARDS THE OHIO VALLEY...EVENTUALLY SPAWNING A WEAK LOW
ACROSS THE TENNESSEE VALLEY. GUIDANCE HAS BEEN HEMMING AND HAWING
WITH JUST HOW FAR NORTH TO BRING THE PRECIP WITH THIS
FEATURE...AND JUST HOW MUCH OF IT WILL REACH INTO THE SOUTHEASTERN
CORNER OF THE CWA. THE LATEST FORECAST TRENDS HAVE BACKED OFF FROM
PREVIOUS...AND DID SCALE BACK ON POPS AS WELL AS COVERAGE. STILL A
LITTLE UNCERTAIN WITH WHERE THE RASN VS STRAIGHT RA LINE WOULD BE
AND WILL MAINTAIN A SORT OF MIX. ALSO OF NOTE FOR COASTAL
LOCATIONS IN THIS SAME TIME FRAME /AS THE INV TROF-LOW SLIDE EAST/
IS THE CHANCE FOR LES. THERMAL PROFILES ACROSS THE SOUTHERN LAKE
WILL BECOME INCREASINGLY UNSTABLE WITH LAKE SURFACE TO H85 DELTA
T`S REACHING THE 12-15C RANGE. EXPECT WEAK SHOWERS TO BEGIN TO
STRETCH FROM LAKE COUNTY IL...EVENTUALLY SOUTH TO COOK AND
GRADUALLY INTO THE MORE TYPICAL LAKE/PORTER IN ORIENTATION. QPF
AMOUNTS NOT LOOKING VERY IMPRESSIVE DURING THE SHORT DURATION AND
WOULD ONLY EXPECT ANYWHERE FROM A TRACE TO MAYBE A TENTH OR TWO OF
ACCUMULATION CLOSE TO THE LAKE TOMORROW AND INTO TOMORROW NIGHT.
THIS WILL ALL BE FOLLOWED BY A FEW DAYS OF QUIET AS ANOTHER RIDGE
OF HIGH PRESSURE SWINGS IN FROM THE NORTHWEST.
A LATE WEEK SYSTEM IS STILL PART OF A LOW CONFIDENCE FORECAST.
GFS HAD BEEN ADVERTISING A WEAK CLIPPER DROPPING FROM THE NORTHERN
PLAINS... AND PREVIOUS EC SOLNS HAD SIMILAR...BUT THE 12Z FLIPPED AND
DEVELOPED A SURFACE LOW THAT LIFTS THROUGH THE MISSISSIPPI
VALLEY...INTO NORTHERN INDIANA...NORTHEAST THROUGH EASTERN
ONTARIO. CONFIDENCE AT THIS POINT ON THAT EURO SOLN IS LOW AND
WILL KEEP THE CHANCE OF SNOW AND NOT BUMP UP (OR DOWN) ANY
CATEGORY UNTIL THE PICTURE IS A LITTLE CLEARER. THE 00Z SOLN BEGAN
TO COME IN AND WAS BACK TO THE ORIGINAL PICTURE WITH THE CLIPPER
RACING THROUGH. DESPITE THE LOWER CONFIDENCE IN THAT FEATURE LATE
THIS WEEK...THE ONE PICTURE OF CLARITY WHAT WILL FOLLOW IT. ALL
LONG RANGE GUIDANCE IS STILL INDICATING THAT THERE WILL BE A LARGE
SURGE OF COLD AIR ENCROACHING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. THERE ARE STILL SOME TIMING DIFFERENCES WITH HOW QUICKLY
THE COLD AIR WILL DUMP IN...WHICH IS DUE IN PART TO THE LARGE
MODEL DIFFERENCES MENTIONED MOMENTS AGO...BUT THE ONE THING THEY
ALL AGREE ON IS HOW COLD THE LOWER LEVELS WILL GET INTO THE
WEEKEND. EVEN A WEEK OUT...THE EC/GFS/GEFS/DGEX/GEM(NHEM THROUGH
F144) ALL HIGHLIGHT H85 TEMPS PLUMMETING TO -16 TO -18
DEGREES...OR EVEN A FEW DEGREES COLDER. TRANSLATE THAT TO THE
SURFACE AND IT WOULD BE POSSIBLE THAT HIGHS WOULD STRUGGLE TO GET
OUT OF THE TEENS FOR MANY LOCATIONS AND OVERNIGHT LOWS LEADING
INTO THE WEEKEND WOULD DIVE BOMB TO THE SINGLE DIGITS /BUT LIKELY A
SMIDGEN WARMER IN THE CHICAGO METRO/. WITH THAT FORECAST STILL
BEING OUT 6-7 DAYS...AND A SLEW OF OTHER WEATHER GOING ON THROUGH
THE EARLY WEEK... WILL ONLY CONTINUE TO TREND DOWN FROM THE
INHERITED LONG RANGE FORECAST. THE BIG SAVING GRACE IS THE LACK OF
SOLID SNOW PACK. IF THAT WERE PRESENT...IT WOULD BE MUCH COLDER.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIG TRENDS THIS AFTERNOON.
* POTENTIAL FOR SOME LAKE EFFECT RAIN/SNOW SHOWERS ON MONDAY.
KJB
//DISCUSSION...UPDATED 18Z...
THE MAIN CONCERNS THIS AFTERNOON ARE THE IFR CIGS MOVING ACROSS
NORTHEASTERN ILLINOIS.
A COLD FRONT IS CURRENTLY MOVING ACROSS NORTHEASTERN ILLINOIS. CIGS
ALONG AND BEHIND THIS FRONT HAVE DROPPED INTO THE IFR RANGE. I
EXPECT THESE CIGS TO LAST FOR A COUPLE OF HOURS THIS AFTERNOON
BEFORE THEY BEGIN TO IMPROVE SOME BY MID TO LATE AFTERNOON. WINDS
WILL PRIMARILY BE WESTERLY WITH A FEW GUSTS AROUND 18KT POSSIBLE
EARLY THIS AFTERNOON.
THE NEXT WEATHER CONCERN WILL BE ON MONDAY AS NORTH TO NORTHEASTERLY
FLOW SETS UP AHEAD OF HIGH PRESSURE ACROSS THE PLAINS STATES. THIS
FLOW PATTERN...IN COMBINATION WITH THE RELATIVELY COLD TEMPERATURES
OVER LAKE MICHIGAN COULD SET THE STAGE FOR SOME LOWER MVFR CIGS AND
SOME LAKE EFFECT RAIN AND SNOW SHOWERS BEGINNING EARLY MONDAY MORNING.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN CIGS IMPROVING TO LOW END MVFR AROUND 21
UTC.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR CIG. CHANCE LIGHT LAKE EFFECT SNOW SHOWERS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...VFR.
ALLSOPP
&&
.MARINE...
153 PM CST
HIGH PRESSURE WILL BUILD ACROSS THE PLAINS STATES ON
MONDAY...SETTING UP NORTH TO NORTHEASTERLY FLOW DOWN LAKE MICHIGAN.
THE FLOW WILL TURN MORE WESTERLY LATE TUESDAY INTO WEDNESDAY AS A
POTENT STORM SYSTEM MOVES EAST ACROSS NORTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT ACROSS LAKE MICHIGAN WEDNESDAY NIGHT.
VERY COLD AIR BEHIND THIS FRONT LOOKS TO SET UP AN UNSTABLE
ATMOSPHERE ACROSS THE LAKE LATER THIS WEEK. THIS LOOKS TO SET UP
CONDITIONS FAVORABLE FOR SOME LAKE EFFECT SNOW SHOWERS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 3 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1149 AM CST SUN DEC 4 2011
.DISCUSSION...
1125 AM CST
FRONTAL BOUNDARY CONTINUES TO STEADILY PUSH EAST ACROSS THE
CWFA...EXPECTED BY MIDDAY TO PUSH THROUGH NORTHWEST INDIANA.
BEHIND THIS BOUNDARY TEMPERATURES IN MANY LOCATIONS HAVE FALLEN
INTO THE UPPER 30S TO LOWER 40S. EXPECT TEMPERATURES TO REMAIN
NEARLY STEADY THROUGHOUT THE REMAINDER OF THE DAY...THEN SLOWLY
BEGIN TO FALL THIS EVENING. ONE CAVEAT FOR HOW LOW TEMPERATURES
MAY FALL TONIGHT WILL BE THE POSSIBILITY OF ABUNDANT CLOUD COVER.
CURRENT GUIDANCE CONTINUES TO INDICATE THAT SKIES WILL STEADILY
BREAK-UP THIS AFTERNOON AND POSSIBLY TURN SCATTERED TONIGHT.
HOWEVER...LOOKING AT THE CURRENT VISIBLE IMAGERY ACROSS THE ENTIRE
REGION AND MANY LOCATIONS UPSTREAM THIS SCENARIO OF THINNING SKIES
LOOKS TO BE IN JEOPARDY. THUS HAVE CONCERNS ABOUT HOW COLD WE WILL
SEE TEMPERATURES FALL TONIGHT. NONETHELESS 850MB THERMAL TROUGH
CONTINUES TO PIVOT EAST...AND REMAIN OVERHEAD TONIGHT. AIDING IN
TEMPERATURES FALLING INTO THE UPPER 20S TO LOWER 30S TONIGHT WILL
BE THE STEADY COLD AIR ADVECTION WITH NORTHERLY WINDS TURNING
NORHTEASTERLY.
WITH AN INCREASING THERMAL DIFFERENTIAL ACROSS THE RELATIVELY
WARMER MARINE ENVIRONMENT...AND MUCH COOLER AIR ALOFT EXPECT A
NARROW CHANNEL OF LAKE MOISTURE TO FORM FROM THE NORTH/NORTHEAST
WINDS. THIS WILL AID IN THE POSSIBILITY OF LAKE EFFECT
FLURRIES/LGT SN. THEN BECOMING MIXED WITH LGT RA AFTER DAYBREAK
MON. THROWING A POTENTIAL MONKEY WRENCH IN THIS SCENARIO COULD BE
THE DEPTH OF THE FAVORED DENDRITIC GROWTH ZONE AND MOISTURE. VERY
MINIMAL VERTICAL ENERGY MAY LIMIT THIS TO POSSIBLY JUST SOME
DRIZZLE. THIS WILL BE THE FIRST CHALLENGE OF THE EVENING FORECAST.
AS THIS COULD END UP BEING FROZEN DRIZZLE WITH TEMPERATURES
POSSIBLY IN THE LOWER 30S.
BEACHLER
//PREV DISCUSSION...
340 AM CST
HIGHLIGHTS THIS WEEK WILL INCLUDE RAIN COMING TO AN END...POSSIBLE
SN/RASN/RA ACROSS THE SOUTHEAST MONDAY...LES POTENTIAL FOR
LAKE/COOK LATE SUNDAY NIGHT INTO MONDAY...TRANSITIONING SOUTH TO
LAKE/PORTER INDIANA BY TUESDAY...A FEW DAYS OF QUIET...FOLLOWED
BY A LATE CLIPPER AND SNOW POTENTIAL AND FINALLY A BLAST OF COLD
BY NEXT WEEKEND.
THE EARLY MORNING SURFACE MAP SHOWED THE SURFACE LOW THAT HAS
BEEN BRINGING THE WET AND ACTIVE WEATHER TO THE AREA
TODAY...CONTINUING TO LIFTING NORTH THROUGH CENTRAL WISCONSIN.
MEANWHILE AN ATTENDANT COLD FRONT LAY ROUGHLY ACROSS THE
MISSISSIPPI RIVER...SOUTHWEST NEARLY TO ST LOUIS. THIS FRONT WILL
CONTINUE TO SLOWLY SWEEP FROM WEST TO EAST THIS MORNING EVENTUALLY
PUSHING ITSELF AND THE PRECIP EAST. THE MOST WIDE SPREAD ECHOES HAVE
PUSHED EAST AND ONLY A FEW SCATTERED SHOWERS ARE LOCATED WITH THE
ACTUAL FRONT. ACROSS EAST CENTRAL IOWA...TEMPERATURES HAVE
DROPPED ENOUGH THAT -SN WAS REPORTED...BUT CLOUD TOPS HAVE WARMED
ENOUGH AND ARE WARMER THAN -10C. THIS MEANS THAT THERE IS NO
LONGER ICE INTRODUCTION INTO THE SATURATED LAYERS BELOW...AND A
FEW LOCATIONS REPORTED U.P. AND OR FZDZ. FOR OUR AREA...AFTER THE
FRONT MOVES THROUGH...LOWER LEVEL MOISTURE WILL REMAIN BUT
PROFILES ARE STILL INDICATIVE OF LIQUID PRECIP AND SURFACE TEMPS
WILL REMAIN ABOVE FREEZING.
THE HRRR AND RUC BOTH HAVE A GOOD HANDLE ON THE WESTERN EDGE OF THE
PRECIP AND FRONTAL LOCATION...AND MOST OF IT SHOULD CLEAR THE
ROCKFORD CORRIDOR NEAR SUNRISE...WITH CHICAGO AND EAST JUST A FEW
HOURS BEYOND. WHILE LOWER LEVEL RH WILL REMAIN PREVALENT WITH AND
SHORTLY BEYOND FROPA...MOISTURE ABOVE -10C WILL DISAPPEAR AND
THERE MAY BE SOME LINGERING DZ INTO THE EARLY MORNING HOURS. THE
BIG PUSH OF COLDER AIR ISNT EXPECTED UNTIL LATER THIS EVENING AND
TEMPERATURES WILL REMAIN ABOVE FREEZING...SO NO CONCERN OVER ANY
OTHER PRECIP TYPES THIS MORNING. HIGH TEMPS WILL GENERALLY BE
SEEN EARLY TODAY...AND SLOWLY FALL THROUGH THE DAY. WINDS WILL
ABATE AS HIGH PRESSURE AND A PERIOD OF DRY...SLOWLY MOVE IN.
THE MAIN UPPER LEVEL TROUGHING THAT STRETCHES FROM ROUGHLY
SASKATCHEWAN...SOUTHWEST THROUGH THE FOUR CORNERS REGION WILL NOT
HAVE MUCH REASON TO MOVE UNTIL THE START OF THE WORKWEEK. PRESENT
SHORTWAVE SEEN ON WATER VAPOR IMAGERY ROUNDING THE BASE OF THE
TROUGH...ACROSS SOUTHERN ARIZONA...WILL DAMPEN SOME AS IT
GETS EJECTED ON THE EASTERN FLANK TODAY AND TONIGHT. AS IT DOES
THIS...IT WILL HELP TO AMPLIFY AN INVERTED TROUGH THAT WILL NOSE
ITS WAY TOWARDS THE OHIO VALLEY...EVENTUALLY SPAWNING A WEAK LOW
ACROSS THE TENNESSEE VALLEY. GUIDANCE HAS BEEN HEMMING AND HAWING
WITH JUST HOW FAR NORTH TO BRING THE PRECIP WITH THIS
FEATURE...AND JUST HOW MUCH OF IT WILL REACH INTO THE SOUTHEASTERN
CORNER OF THE CWA. THE LATEST FORECAST TRENDS HAVE BACKED OFF FROM
PREVIOUS...AND DID SCALE BACK ON POPS AS WELL AS COVERAGE. STILL A
LITTLE UNCERTAIN WITH WHERE THE RASN VS STRAIGHT RA LINE WOULD BE
AND WILL MAINTAIN A SORT OF MIX. ALSO OF NOTE FOR COASTAL
LOCATIONS IN THIS SAME TIME FRAME /AS THE INV TROF-LOW SLIDE EAST/
IS THE CHANCE FOR LES. THERMAL PROFILES ACROSS THE SOUTHERN LAKE
WILL BECOME INCREASINGLY UNSTABLE WITH LAKE SURFACE TO H85 DELTA
T`S REACHING THE 12-15C RANGE. EXPECT WEAK SHOWERS TO BEGIN TO
STRETCH FROM LAKE COUNTY IL...EVENTUALLY SOUTH TO COOK AND
GRADUALLY INTO THE MORE TYPICAL LAKE/PORTER IN ORIENTATION. QPF
AMOUNTS NOT LOOKING VERY IMPRESSIVE DURING THE SHORT DURATION AND
WOULD ONLY EXPECT ANYWHERE FROM A TRACE TO MAYBE A TENTH OR TWO OF
ACCUMULATION CLOSE TO THE LAKE TOMORROW AND INTO TOMORROW NIGHT.
THIS WILL ALL BE FOLLOWED BY A FEW DAYS OF QUIET AS ANOTHER RIDGE
OF HIGH PRESSURE SWINGS IN FROM THE NORTHWEST.
A LATE WEEK SYSTEM IS STILL PART OF A LOW CONFIDENCE FORECAST.
GFS HAD BEEN ADVERTISING A WEAK CLIPPER DROPPING FROM THE NORTHERN
PLAINS... AND PREVIOUS EC SOLNS HAD SIMILAR...BUT THE 12Z FLIPPED AND
DEVELOPED A SURFACE LOW THAT LIFTS THROUGH THE MISSISSIPPI
VALLEY...INTO NORTHERN INDIANA...NORTHEAST THROUGH EASTERN
ONTARIO. CONFIDENCE AT THIS POINT ON THAT EURO SOLN IS LOW AND
WILL KEEP THE CHANCE OF SNOW AND NOT BUMP UP (OR DOWN) ANY
CATEGORY UNTIL THE PICTURE IS A LITTLE CLEARER. THE 00Z SOLN BEGAN
TO COME IN AND WAS BACK TO THE ORIGINAL PICTURE WITH THE CLIPPER
RACING THROUGH. DESPITE THE LOWER CONFIDENCE IN THAT FEATURE LATE
THIS WEEK...THE ONE PICTURE OF CLARITY WHAT WILL FOLLOW IT. ALL
LONG RANGE GUIDANCE IS STILL INDICATING THAT THERE WILL BE A LARGE
SURGE OF COLD AIR ENCROACHING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. THERE ARE STILL SOME TIMING DIFFERENCES WITH HOW QUICKLY
THE COLD AIR WILL DUMP IN...WHICH IS DUE IN PART TO THE LARGE
MODEL DIFFERENCES MENTIONED MOMENTS AGO...BUT THE ONE THING THEY
ALL AGREE ON IS HOW COLD THE LOWER LEVELS WILL GET INTO THE
WEEKEND. EVEN A WEEK OUT...THE EC/GFS/GEFS/DGEX/GEM(NHEM THROUGH
F144) ALL HIGHLIGHT H85 TEMPS PLUMMETING TO -16 TO -18
DEGREES...OR EVEN A FEW DEGREES COLDER. TRANSLATE THAT TO THE
SURFACE AND IT WOULD BE POSSIBLE THAT HIGHS WOULD STRUGGLE TO GET
OUT OF THE TEENS FOR MANY LOCATIONS AND OVERNIGHT LOWS LEADING
INTO THE WEEKEND WOULD DIVE BOMB TO THE SINGLE DIGITS /BUT LIKELY A
SMIDGEN WARMER IN THE CHICAGO METRO/. WITH THAT FORECAST STILL
BEING OUT 6-7 DAYS...AND A SLEW OF OTHER WEATHER GOING ON THROUGH
THE EARLY WEEK... WILL ONLY CONTINUE TO TREND DOWN FROM THE
INHERITED LONG RANGE FORECAST. THE BIG SAVING GRACE IS THE LACK OF
SOLID SNOW PACK. IF THAT WERE PRESENT...IT WOULD BE MUCH COLDER.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIG TRENDS THIS AFTERNOON.
* POTENTIAL FOR SOME LAKE EFFECT RAIN/SNOW SHOWERS ON MONDAY.
KJB
//DISCUSSION...UPDATED 18Z...
THE MAIN CONCERNS THIS AFTERNOON ARE THE IFR CIGS MOVING ACROSS
NORTHEASTERN ILLINOIS.
A COLD FRONT IS CURRENTLY MOVING ACROSS NORTHEASTERN ILLINOIS. CIGS
ALONG AND BEHIND THIS FRONT HAVE DROPPED INTO THE IFR RANGE. I
EXPECT THESE CIGS TO LAST FOR A COUPLE OF HOURS THIS AFTERNOON
BEFORE THEY BEGIN TO IMPROVE SOME BY MID TO LATE AFTERNOON. WINDS
WILL PRIMARILY BE WESTERLY WITH A FEW GUSTS AROUND 18KT POSSIBLE
EARLY THIS AFTERNOON.
THE NEXT WEATHER CONCERN WILL BE ON MONDAY AS NORTH TO NORTHEASTERLY
FLOW SETS UP AHEAD OF HIGH PRESSURE ACROSS THE PLAINS STATES. THIS
FLOW PATTERN...IN COMBINATION WITH THE RELATIVELY COLD TEMPERATURES
OVER LAKE MICHIGAN COULD SET THE STAGE FOR SOME LOWER MVFR CIGS AND
SOME LAKE EFFECT RAIN AND SNOW SHOWERS BEGINNING EARLY MONDAY MORNING.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN CIGS IMPROVING TO LOW END MVFR AROUND 21
UTC.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR CIG. CHANCE LIGHT LAKE EFFECT SNOW SHOWERS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...VFR.
ALLSOPP
&&
.MARINE...
133 AM CST
A POWERFUL STORM WAS MOVING THROUGH THE GREAT LAKES THIS MORNING.
LOW PRESSURE WILL MOVE QUICKLY FROM WISCONSIN TO NORTHERN LAKE
MICHIGAN THIS MORNING...THEN ON TO QUEBEC BY EVENING. EAST OF THE
TRACK OF THE LOW A VERY STRONG SOUTHERLY LOW LEVEL JET WAS
OCCURRING...WITH 50 KT WINDS JUST 1 TO 2 THOUSAND FEET OFF THE
SURFACE. A STRONG INVERSION WAS LIMITING MIXING BUT GALE FORCE
WINDS WERE WORKING DOWN TO THE LAKE SURFACE OVER THE SOUTH HALF
WITH SOME GALE FORCE GUSTS ON THE EAST SIDE OF THE NORTH HALF OF
THE LAKE. WINDS SHOULD DROP OFF PRETTY QUICKLY AS THE LOW MOVES
RAPIDLY NORTHEAST TODAY AND GALES SHOULD END BY ABOUT NOON.
PRESENTLY GALE WARNING GOES THROUGH MID AFTERNOON BUT IT MAY BE
CANCELED EARLY. WINDS WILL VEER FROM SOUTH TO NORTHWEST THROUGH
THE COURSE OF THE DAY.
TONIGHT THROUGH MONDAY ANOTHER LOW WILL MOVE FROM THE TEXAS COAST
UP THROUGH THE OHIO VALLEY WHILE STRONG HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THIS WILL PRODUCE A PERIOD OF NORTHERLY WINDS
ON LAKE MICHIGAN. THE REST OF THE WEEK HIGH PRESSURE WILL DOMINATE
THE CENTRAL U.S. WHILE LOW PRESSURE BECOMES ANCHORED OVER
NORTHEAST CANADA. THIS WILL PRODUCE A PROLONGED PERIOD OF WESTERLY
WINDS OVER LAKE MICHIGAN FROM MID WEEK INTO THE WEEKEND.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 3 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1135 AM CST SUN DEC 4 2011
.DISCUSSION...
1125 AM CST
FRONTAL BOUNDARY CONTINUES TO STEADILY PUSH EAST ACROSS THE
CWFA...EXPECTED BY MIDDAY TO PUSH THROUGH NORTHWEST INDIANA.
BEHIND THIS BOUNDARY TEMPERATURES IN MANY LOCATIONS HAVE FALLEN
INTO THE UPPER 30S TO LOWER 40S. EXPECT TEMPERATURES TO REMAIN
NEARLY STEADY THROUGHOUT THE REMAINDER OF THE DAY...THEN SLOWLY
BEGIN TO FALL THIS EVENING. ONE CAVEAT FOR HOW LOW TEMPERATURES
MAY FALL TONIGHT WILL BE THE POSSIBILITY OF ABUNDANT CLOUD COVER.
CURRENT GUIDANCE CONTINUES TO INDICATE THAT SKIES WILL STEADILY
BREAK-UP THIS AFTERNOON AND POSSIBLY TURN SCATTERED TONIGHT.
HOWEVER...LOOKING AT THE CURRENT VISIBLE IMAGERY ACROSS THE ENTIRE
REGION AND MANY LOCATIONS UPSTREAM THIS SCENARIO OF THINNING SKIES
LOOKS TO BE IN JEOPARDY. THUS HAVE CONCERNS ABOUT HOW COLD WE WILL
SEE TEMPERATURES FALL TONIGHT. NONETHELESS 850MB THERMAL TROUGH
CONTINUES TO PIVOT EAST...AND REMAIN OVERHEAD TONIGHT. AIDING IN
TEMPERATURES FALLING INTO THE UPPER 20S TO LOWER 30S TONIGHT WILL
BE THE STEADY COLD AIR ADVECTION WITH NORTHERLY WINDS TURNING
NORHTEASTERLY.
WITH AN INCREASING THERMAL DIFFERENTIAL ACROSS THE RELATIVELY
WARMER MARINE ENVIRONMENT...AND MUCH COOLER AIR ALOFT EXPECT A
NARROW CHANNEL OF LAKE MOISTURE TO FORM FROM THE NORTH/NORTHEAST
WINDS. THIS WILL AID IN THE POSSIBILITY OF LAKE EFFECT
FLURRIES/LGT SN. THEN BECOMING MIXED WITH LGT RA AFTER DAYBREAK
MON. THROWING A POTENTIAL MONKEY WRENCH IN THIS SCENARIO COULD BE
THE DEPTH OF THE FAVORED DENDRITIC GROWTH ZONE AND MOISTURE. VERY
MINIMAL VERTICAL ENERGY MAY LIMIT THIS TO POSSIBLY JUST SOME
DRIZZLE. THIS WILL BE THE FIRST CHALLENGE OF THE EVENING FORECAST.
AS THIS COULD END UP BEING FROZEN DRIZZLE WITH TEMPERATURES
POSSIBLY IN THE LOWER 30S.
BEACHLER
&&
.PREV DISCUSSION...
340 AM CST
HIGHLIGHTS THIS WEEK WILL INCLUDE RAIN COMING TO AN END...POSSIBLE
SN/RASN/RA ACROSS THE SOUTHEAST MONDAY...LES POTENTIAL FOR
LAKE/COOK LATE SUNDAY NIGHT INTO MONDAY...TRANSITIONING SOUTH TO
LAKE/PORTER INDIANA BY TUESDAY...A FEW DAYS OF QUIET...FOLLOWED
BY A LATE CLIPPER AND SNOW POTENTIAL AND FINALLY A BLAST OF COLD
BY NEXT WEEKEND.
THE EARLY MORNING SURFACE MAP SHOWED THE SURFACE LOW THAT HAS
BEEN BRINGING THE WET AND ACTIVE WEATHER TO THE AREA
TODAY...CONTINUING TO LIFTING NORTH THROUGH CENTRAL WISCONSIN.
MEANWHILE AN ATTENDANT COLD FRONT LAY ROUGHLY ACROSS THE
MISSISSIPPI RIVER...SOUTHWEST NEARLY TO ST LOUIS. THIS FRONT WILL
CONTINUE TO SLOWLY SWEEP FROM WEST TO EAST THIS MORNING EVENTUALLY
PUSHING ITSELF AND THE PRECIP EAST. THE MOST WIDE SPREAD ECHOES HAVE
PUSHED EAST AND ONLY A FEW SCATTERED SHOWERS ARE LOCATED WITH THE
ACTUAL FRONT. ACROSS EAST CENTRAL IOWA...TEMPERATURES HAVE
DROPPED ENOUGH THAT -SN WAS REPORTED...BUT CLOUD TOPS HAVE WARMED
ENOUGH AND ARE WARMER THAN -10C. THIS MEANS THAT THERE IS NO
LONGER ICE INTRODUCTION INTO THE SATURATED LAYERS BELOW...AND A
FEW LOCATIONS REPORTED U.P. AND OR FZDZ. FOR OUR AREA...AFTER THE
FRONT MOVES THROUGH...LOWER LEVEL MOISTURE WILL REMAIN BUT
PROFILES ARE STILL INDICATIVE OF LIQUID PRECIP AND SURFACE TEMPS
WILL REMAIN ABOVE FREEZING.
THE HRRR AND RUC BOTH HAVE A GOOD HANDLE ON THE WESTERN EDGE OF THE
PRECIP AND FRONTAL LOCATION...AND MOST OF IT SHOULD CLEAR THE
ROCKFORD CORRIDOR NEAR SUNRISE...WITH CHICAGO AND EAST JUST A FEW
HOURS BEYOND. WHILE LOWER LEVEL RH WILL REMAIN PREVALENT WITH AND
SHORTLY BEYOND FROPA...MOISTURE ABOVE -10C WILL DISAPPEAR AND
THERE MAY BE SOME LINGERING DZ INTO THE EARLY MORNING HOURS. THE
BIG PUSH OF COLDER AIR ISNT EXPECTED UNTIL LATER THIS EVENING AND
TEMPERATURES WILL REMAIN ABOVE FREEZING...SO NO CONCERN OVER ANY
OTHER PRECIP TYPES THIS MORNING. HIGH TEMPS WILL GENERALLY BE
SEEN EARLY TODAY...AND SLOWLY FALL THROUGH THE DAY. WINDS WILL
ABATE AS HIGH PRESSURE AND A PERIOD OF DRY...SLOWLY MOVE IN.
THE MAIN UPPER LEVEL TROUGHING THAT STRETCHES FROM ROUGHLY
SASKATCHEWAN...SOUTHWEST THROUGH THE FOUR CORNERS REGION WILL NOT
HAVE MUCH REASON TO MOVE UNTIL THE START OF THE WORKWEEK. PRESENT
SHORTWAVE SEEN ON WATER VAPOR IMAGERY ROUNDING THE BASE OF THE
TROUGH...ACROSS SOUTHERN ARIZONA...WILL DAMPEN SOME AS IT
GETS EJECTED ON THE EASTERN FLANK TODAY AND TONIGHT. AS IT DOES
THIS...IT WILL HELP TO AMPLIFY AN INVERTED TROUGH THAT WILL NOSE
ITS WAY TOWARDS THE OHIO VALLEY...EVENTUALLY SPAWNING A WEAK LOW
ACROSS THE TENNESSEE VALLEY. GUIDANCE HAS BEEN HEMMING AND HAWING
WITH JUST HOW FAR NORTH TO BRING THE PRECIP WITH THIS
FEATURE...AND JUST HOW MUCH OF IT WILL REACH INTO THE SOUTHEASTERN
CORNER OF THE CWA. THE LATEST FORECAST TRENDS HAVE BACKED OFF FROM
PREVIOUS...AND DID SCALE BACK ON POPS AS WELL AS COVERAGE. STILL A
LITTLE UNCERTAIN WITH WHERE THE RASN VS STRAIGHT RA LINE WOULD BE
AND WILL MAINTAIN A SORT OF MIX. ALSO OF NOTE FOR COASTAL
LOCATIONS IN THIS SAME TIME FRAME /AS THE INV TROF-LOW SLIDE EAST/
IS THE CHANCE FOR LES. THERMAL PROFILES ACROSS THE SOUTHERN LAKE
WILL BECOME INCREASINGLY UNSTABLE WITH LAKE SURFACE TO H85 DELTA
T`S REACHING THE 12-15C RANGE. EXPECT WEAK SHOWERS TO BEGIN TO
STRETCH FROM LAKE COUNTY IL...EVENTUALLY SOUTH TO COOK AND
GRADUALLY INTO THE MORE TYPICAL LAKE/PORTER IN ORIENTATION. QPF
AMOUNTS NOT LOOKING VERY IMPRESSIVE DURING THE SHORT DURATION AND
WOULD ONLY EXPECT ANYWHERE FROM A TRACE TO MAYBE A TENTH OR TWO OF
ACCUMULATION CLOSE TO THE LAKE TOMORROW AND INTO TOMORROW NIGHT.
THIS WILL ALL BE FOLLOWED BY A FEW DAYS OF QUIET AS ANOTHER RIDGE
OF HIGH PRESSURE SWINGS IN FROM THE NORTHWEST.
A LATE WEEK SYSTEM IS STILL PART OF A LOW CONFIDENCE FORECAST.
GFS HAD BEEN ADVERTISING A WEAK CLIPPER DROPPING FROM THE NORTHERN
PLAINS... AND PREVIOUS EC SOLNS HAD SIMILAR...BUT THE 12Z FLIPPED AND
DEVELOPED A SURFACE LOW THAT LIFTS THROUGH THE MISSISSIPPI
VALLEY...INTO NORTHERN INDIANA...NORTHEAST THROUGH EASTERN
ONTARIO. CONFIDENCE AT THIS POINT ON THAT EURO SOLN IS LOW AND
WILL KEEP THE CHANCE OF SNOW AND NOT BUMP UP (OR DOWN) ANY
CATEGORY UNTIL THE PICTURE IS A LITTLE CLEARER. THE 00Z SOLN BEGAN
TO COME IN AND WAS BACK TO THE ORIGINAL PICTURE WITH THE CLIPPER
RACING THROUGH. DESPITE THE LOWER CONFIDENCE IN THAT FEATURE LATE
THIS WEEK...THE ONE PICTURE OF CLARITY WHAT WILL FOLLOW IT. ALL
LONG RANGE GUIDANCE IS STILL INDICATING THAT THERE WILL BE A LARGE
SURGE OF COLD AIR ENCROACHING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. THERE ARE STILL SOME TIMING DIFFERENCES WITH HOW QUICKLY
THE COLD AIR WILL DUMP IN...WHICH IS DUE IN PART TO THE LARGE
MODEL DIFFERENCES MENTIONED MOMENTS AGO...BUT THE ONE THING THEY
ALL AGREE ON IS HOW COLD THE LOWER LEVELS WILL GET INTO THE
WEEKEND. EVEN A WEEK OUT...THE EC/GFS/GEFS/DGEX/GEM(NHEM THROUGH
F144) ALL HIGHLIGHT H85 TEMPS PLUMMETING TO -16 TO -18
DEGREES...OR EVEN A FEW DEGREES COLDER. TRANSLATE THAT TO THE
SURFACE AND IT WOULD BE POSSIBLE THAT HIGHS WOULD STRUGGLE TO GET
OUT OF THE TEENS FOR MANY LOCATIONS AND OVERNIGHT LOWS LEADING
INTO THE WEEKEND WOULD DIVE BOMB TO THE SINGLE DIGITS /BUT LIKELY A
SMIDGEN WARMER IN THE CHICAGO METRO/. WITH THAT FORECAST STILL
BEING OUT 6-7 DAYS...AND A SLEW OF OTHER WEATHER GOING ON THROUGH
THE EARLY WEEK... WILL ONLY CONTINUE TO TREND DOWN FROM THE
INHERITED LONG RANGE FORECAST. THE BIG SAVING GRACE IS THE LACK OF
SOLID SNOW PACK. IF THAT WERE PRESENT...IT WOULD BE MUCH COLDER.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LOW MVFR TO IFR POST FRONTAL CIGS MOVING BACK ACROSS THE
TERMINALS LATER THIS MORNING.
KJB
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE OVER NORTHERN LAKE MICHIGAN MOVING QUICKLY NORTHEAST
THIS MORNING. MOST OF THE RAIN HAS MOVED OUT OF THE AREA. ONLY A
FEW LIGHT SHOWERS REMAIN ALONG THE COLD FRONT...WHICH STRETCHES
FROM THE LOW TO JUST WEST OF RFD TO STL. JUST KEPT A VCSH IN FOR A
FEW HOURS TO COVER A POSSIBLE BRIEF LIGHT SHOWER THROUGH MID
MORNING. STRONG SSW WINDS STILL GUSTING TO AROUND 25 KTS EARLY
THIS MORNING. WINDS WILL SHIFT WEST WITH COLD FRONTAL PASSAGE MID
MORNING AND DIMINISH. MAY STILL SEE SOME GUSTS TO AROUND 20 KT OR
SO THROUGH MIDDAY. WINDS WILL BECOME NORTHWEST AND FALL TO LESS
THAN 10 KT BY LATE AFTERNOON.
MAIN ISSUE TODAY WILL BE LOW CEILINGS...PRESENTLY RUNNING AROUND
1000-1500 FT. SOME IFR NOTED OVER IA AND WESTERN IL BEHIND THE
COLD FRONT. BUT WITH EVERYTHING LIFTING NORTHEAST...AND LOOKING
AT MODEL SOUNDINGS...DONT EXPECT IFR CIGS TO IMPACT THE CHICAGO
AREA TERMINALS. RFD MY FLIRT WITH IFR THROUGH THE MORNING HOURS
AND HAVE COVERED THIS WITH A TEMPO GROUP. SHOULD SEE AN IMPROVING
TREND THROUGH THE AFTERNOON. THE BACK EDGE OF THE STRATUS OVER THE
DAKOTAS...NEB...INTO NW MO IS PUSHING EAST ON SATELLITE IMAGERY.
THERE IS A POSSIBILITY OF STRATUS SCATTERING OUT OVER NORTHERN IL
TOWARDS EVENING OR OVERNIGHT...BUT CONFIDENCE IN THAT HAPPENING IS
LOW AND WILL HANG ON TO MVFR CIGS THROUGH THE NIGHT AT THIS
POINT.
WINDS WILL GRADUALLY VEER NORTH NORTHEAST LATE TONIGHT INTO
MONDAY MORNING. AS COLDER AIR MOVES DOWN THE LAKE...SOME LAKE
EFFECT CLOUDS AND LIGHT SNOW SHOWERS ARE POSSIBLE MONDAY BUT AT
THIS TIME IT APPEARS THE CLOUD DEPTH WILL BE TOO SHALLOW TO
SUPPORT ANY SIGNIFICANT LAKE EFFECT FOR MONDAY.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN MVFR CIGS.
* LOW CONFIDENCE IN CIGS DROPPING INTO THE IFR CATEGORY.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR CIG. CHANCE LIGHT LAKE EFFECT SNOW SHOWERS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...VFR.
ALLSOPP
&&
.MARINE...
133 AM CST
A POWERFUL STORM WAS MOVING THROUGH THE GREAT LAKES THIS MORNING.
LOW PRESSURE WILL MOVE QUICKLY FROM WISCONSIN TO NORTHERN LAKE
MICHIGAN THIS MORNING...THEN ON TO QUEBEC BY EVENING. EAST OF THE
TRACK OF THE LOW A VERY STRONG SOUTHERLY LOW LEVEL JET WAS
OCCURRING...WITH 50 KT WINDS JUST 1 TO 2 THOUSAND FEET OFF THE
SURFACE. A STRONG INVERSION WAS LIMITING MIXING BUT GALE FORCE
WINDS WERE WORKING DOWN TO THE LAKE SURFACE OVER THE SOUTH HALF
WITH SOME GALE FORCE GUSTS ON THE EAST SIDE OF THE NORTH HALF OF
THE LAKE. WINDS SHOULD DROP OFF PRETTY QUICKLY AS THE LOW MOVES
RAPIDLY NORTHEAST TODAY AND GALES SHOULD END BY ABOUT NOON.
PRESENTLY GALE WARNING GOES THROUGH MID AFTERNOON BUT IT MAY BE
CANCELED EARLY. WINDS WILL VEER FROM SOUTH TO NORTHWEST THROUGH
THE COURSE OF THE DAY.
TONIGHT THROUGH MONDAY ANOTHER LOW WILL MOVE FROM THE TEXAS COAST
UP THROUGH THE OHIO VALLEY WHILE STRONG HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THIS WILL PRODUCE A PERIOD OF NORTHERLY WINDS
ON LAKE MICHIGAN. THE REST OF THE WEEK HIGH PRESSURE WILL DOMINATE
THE CENTRAL U.S. WHILE LOW PRESSURE BECOMES ANCHORED OVER
NORTHEAST CANADA. THIS WILL PRODUCE A PROLONGED PERIOD OF WESTERLY
WINDS OVER LAKE MICHIGAN FROM MID WEEK INTO THE WEEKEND.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 3 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
547 PM EST SUN DEC 4 2011
.SYNOPSIS...
WITH HIGH PRESSURE EAST OF THE REGION OUR ATTENTION TURNS TO A
SLOW MOVING FRONTAL SYSTEM APPROACHING PENNSYLVANIA. CLOUDS FROM
THIS FRONT WILL OVERSPREAD TONIGHT. ON MONDAY RAINFALL WILL INCREASE
IN COVERAGE AND INTENSITY OVER THE WEST AND SPREAD ACROSS CENTRAL
PENNSYLVANIA OVERNIGHT. TEMPERATURES WILL CONTINUE WELL ABOVE
AVERAGE WITH THIS SYSTEM...UNTIL A STRONG COLD FRONT BRING
TEMPERATURES BACK DOWN TO AVERAGE READINGS LATE TUESDAY AND
WEDNESDAY. ANOTHER STORM SYSTEM WILL APPROACH THE REGION FROM THE
SOUTH ON THURSDAY. THIS STORM HAS THE POTENTIAL TO BRING SOME
WINTRY OR MIXED PRECIPITATION DEPENDING ON THE TRACK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
TRANQUIL WEATHER WILL PERSIST OVERNIGHT ACROSS MOST OF THE REGION
WITH JUST AREAS OF MAINLY CIRROSTRATUS...AND SOME HIGH-BASED ALTO
CU DRIFTING NE.
15Z SREF AND 21Z RUC SHOWS SOME LIGHT SHOWERS EDGING INTO WARREN
AND PERHAPS ELK/MCKEAN COUNTIES AFTER 07Z. EVEN THERE...QPF WILL
BE LIGHT AND LESS THAN 0.10 BY 12Z MONDAY.
VERY MILD TEMPS FOR EARLY DECEMBER WILL CONTINUE THROUGH TONIGHT.
THANKS TO THE GENERALLY LIGHT SOUTHERLY BREEZE...AND FAIR AMOUNT
OF CLOUD COVER...TEMPS WILL ONLY REACH THE UPPER 30S TO LOWER 40S
FOR MINS /WHICH WILL BE 10-15F ABOVE NORMAL...WITH THE GREATEST
DEPARTURES OCCURRING ACROSS THE MOUNTAINS/.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
CLOUDS LOWER AND THICKEN AS FRONTAL BOUNDARY APPROACHES.
PRECIPITATION WILL INCREASE IN THE AFTERNOON HOURS AND BECOME A
STEADY LIGHT RAIN OVERNIGHT. FRONT STILL WEST OF AREA SO MILD
TEMPERATURES CONTINUE THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS AGREE ON A COLD FRONT PUSHING ACROSS PA ON TUE...KEEPING
RAIN CHANCES HIGH...ESPECIALLY ACROSS THE SOUTHERN MTNS AND SUSQ
VALLEY. TEMPS TUE START OFF MILD...BUT WILL LIKELY REMAIN STEADY
OR FALL A BIT IN THE AFTERNOON...ESP IN THE NW. NO LARGE PUSH OF
COLD AIR BEHIND FRONT EVIDENT THOUGH.
LINGERING CHANCE FOR LIGHT RAIN/SNOW SHOWERS TUE NIGHT INTO WED AS
NARROW TROUGH AND COOLER AIR SLIDES OVERHEAD.
MUCH UNCERTAINTY IN LATE WEEK SOLUTIONS AS LARGE MODEL DIVERGENCE
CONTINUES. WAVE OF LOW PRESSURE SLIDES UP/EAST OF THE APPALACHIANS
THU...WITH ECMWF CONTINUING TO TRACK THIS TO OUR SE...THOUGH THE
GFS SOLUTION CONTINUES TO BECOME GRADUALLY MORE INTERESTING WITH A
MORE NORTHERLY TRACK. TOUGH TO RESOLVE THIS IN THE GRIDS OTHER
THAN TO EDGE POPS UPWARD A BIT ON THU AND SEE HOW THIS PLAYS OUT.
COULD BRING POTENTIAL FOR 0.50 INCH QPF...WITH SOME OF THAT
FALLING AS SNOW IF THE GFS SOLUTION WINS OUT...THOUGH AM STILL
LEANING MORE TOWARD THE ECMWF SOLUTION AT THIS TIME.
TROUGH DIGS IN FROM THE NW FRI NIGHT INTO SAT...BRINGING NOTICABLY
COLDER TEMPS AND WESTERLY FLOW. THIS WILL ALSO BRING A GOOD CHANCE
FOR LAKE EFFECT SNOW SHOWERS IN THE NW MTNS SAT. TEMPS SHOULD
BEGIN TO REBOUND EARLY NEXT WEEK.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
SOME ISOLATED PRE-FRONTAL SHOWERS MAY MOVE INTO BFD EARLY
TOMORROW MORNING...ALONG WITH SOME MVFR VSBYS. CALM WINDS AND LOW
LEVEL MOISTURE WILL ALLOW FOR FOG FORMATION ACROSS THE SUSQ VALLEY
OVERNIGHT. LATEST MDL DATA SUGGEST IFR VSBYS ARE LIKELY AT
IPT/MDT/LNS LATE TONIGHT. FOG OVER THE SUSQ VALLEY SHOULD
DISSIPATE BY MIDDAY MONDAY.
OUTLOOK...
MON...RAIN/LOW CIGS POSSIBLE...MAINLY NW.
TUE...RAIN/LOW CIGS POSSIBLE.
WED...RAIN AREA WIDE TRANSITIONS TO SHSN NW.
THU...LOW CIGS...SHSN NW.
FRI...LOW CIGS/LAKE EFFECT SHOWERS POSSIBLE MAINLY NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...ROSS/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD/KREKELER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
519 PM EST SUN DEC 4 2011
.SYNOPSIS...
WITH HIGH PRESSURE EAST OF THE REGION OUR ATTENTION TURNS TO A
SLOW MOVING FRONTAL SYSTEM APPROACHING PENNSYLVANIA. CLOUDS FROM
THIS FRONT WILL OVERSPREAD TONIGHT. ON MONDAY RAINFALL WILL INCREASE
IN COVERAGE AND INTENSITY OVER THE WEST AND SPREAD ACROSS CENTRAL
PENNSYLVANIA OVERNIGHT. TEMPERATURES WILL CONTINUE WELL ABOVE
AVERAGE WITH THIS SYSTEM...UNTIL A STRONG COLD FRONT BRING
TEMPERATURES BACK DOWN TO AVERAGE READINGS LATE TUESDAY AND
WEDNESDAY. ANOTHER STORM SYSTEM WILL APPROACH THE REGION FROM THE
SOUTH ON THURSDAY. THIS STORM HAS THE POTENTIAL TO BRING SOME
WINTRY OR MIXED PRECIPITATION DEPENDING ON THE TRACK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
TRANQUIL WEATHER WILL PERSIST OVERNIGHT ACROSS MOST OF THE REGION
WITH JUST AREAS OF MAINLY CIRROSTRATUS...AND SOME HIGH-BASED ALTO
CU DRIFTING NE.
15Z SREF AND 21Z RUC SHOWS SOME LIGHT SHOWERS EDGING INTO WARREN
AND PERHAPS ELK/MCKEAN COUNTIES AFTER 07Z. EVEN THERE...QPF WILL
BE LIGHT AND LESS THAN 0.10 BY 12Z MONDAY.
VERY MILD TEMPS FOR EARLY DECEMBER WILL CONTINUE THROUGH TONIGHT.
THANKS TO THE GENERALLY LIGHT SOUTHERLY BREEZE...AND FAIR AMOUNT
OF CLOUD COVER...TEMPS WILL ONLY REACH THE UPPER 30S TO LOWER 40S
FOR MINS /WHICH WILL BE 10-15F ABOVE NORMAL...WITH THE GREATEST
DEPARTURES OCCURRING ACROSS THE MOUNTAINS/.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
CLOUDS LOWER AND THICKEN AS FRONTAL BOUNDARY APPROACHES.
PRECIPITATION WILL INCREASE IN THE AFTERNOON HOURS AND BECOME A
STEADY LIGHT RAIN OVERNIGHT. FRONT STILL WEST OF AREA SO MILD
TEMPERATURES CONTINUE THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS AGREE ON A COLD FRONT PUSHING ACROSS PA ON TUE...KEEPING
RAIN CHANCES HIGH...ESPECIALLY ACROSS THE SOUTHERN MTNS AND SUSQ
VALLEY. TEMPS TUE START OFF MILD...BUT WILL LIKELY REMAIN STEADY
OR FALL A BIT IN THE AFTERNOON...ESP IN THE NW. NO LARGE PUSH OF
COLD AIR BEHIND FRONT EVIDENT THOUGH.
LINGERING CHANCE FOR LIGHT RAIN/SNOW SHOWERS TUE NIGHT INTO WED AS
NARROW TROUGH AND COOLER AIR SLIDES OVERHEAD.
MUCH UNCERTAINTY IN LATE WEEK SOLUTIONS AS LARGE MODEL DIVERGENCE
CONTINUES. WAVE OF LOW PRESSURE SLIDES UP/EAST OF THE APPALACHIANS
THU...WITH ECMWF CONTINUING TO TRACK THIS TO OUR SE...THOUGH THE
GFS SOLUTION CONTINUES TO BECOME GRADUALLY MORE INTERESTING WITH A
MORE NORTHERLY TRACK. TOUGH TO RESOLVE THIS IN THE GRIDS OTHER
THAN TO EDGE POPS UPWARD A BIT ON THU AND SEE HOW THIS PLAYS OUT.
COULD BRING POTENTIAL FOR 0.50 INCH QPF...WITH SOME OF THAT
FALLING AS SNOW IF THE GFS SOLUTION WINS OUT...THOUGH AM STILL
LEANING MORE TOWARD THE ECMWF SOLUTION AT THIS TIME.
TROUGH DIGS IN FROM THE NW FRI NIGHT INTO SAT...BRINGING NOTICABLY
COLDER TEMPS AND WESTERLY FLOW. THIS WILL ALSO BRING A GOOD CHANCE
FOR LAKE EFFECT SNOW SHOWERS IN THE NW MTNS SAT. TEMPS SHOULD
BEGIN TO REBOUND EARLY NEXT WEEK.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
LLWS IS POSSIBLE OVER BFD EARLY THIS AFTERNOON...MAINLY OVER THE
NW MTNS. SOME ISOLATED PRE-FRONTAL SHOWERS MAY MOVE INTO BFD
EARLY TOMORROW MORNING...ALONG WITH SOME MVFR VSBYS. CALM WINDS
AND LOW LEVEL MOISTURE WILL ALLOW FOR MVFR CONDITIONS ALONG THE
LOWER SUSQ TOMORROW MORNING. THESE CONDITIONS SHOULD CONTINUE
UNTIL 15Z BEFORE LIFTING.
OUTLOOK...
MON...RAIN/LOW CIGS POSSIBLE...MAINLY NW.
TUE...RAIN/LOW CIGS POSSIBLE.
WED...RAIN AREA WIDE TRANSITIONS TO SHSN NW.
THU...LOW CIGS...SHSN NW.
FRI...LOW CIGS/LAKE EFFECT SHOWERS POSSIBLE MAINLY NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...ROSS/LAMBERT
LONG TERM...RXR
AVIATION...KREKELER
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1020 AM CST SUN DEC 4 2011
.DISCUSSION...
STRATUS SLOW TO EXIT THIS MORNING SO HAVE SLOWED THE EASTWARD
PROGRESSION. THIS OF COURSE ALSO MEANS A LITTLE SLOWER RISE IN
TEMPERATURES IN THESE AREAS WHICH WILL MEAN TEMPERATURES STUCK IN
THE LOWER TO MID 20S. NOT MUCH WIND TO SPEAK OF FOR THE NEXT SEVERAL
HOURS HOWEVER SO NOT QUITE AS COLD AS IT COULD BE. LOW PRESSURE IS
DEVELOPING ACROSS THE WESTERN HIGH PLAINS AND WILL MOVE ACROSS SOUTH
DAKOTA THROUGH THE NIGHT. THIS WILL BRING A STRONG NORTH TO
NORTHWEST WIND TONIGHT WHICH WILL CARRY INTO TOMORROW. OTHERWISE...A
WEAK THERMAL/THETA E RIDGE IN THE LOW AND MID LEVELS WILL SPREAD
INTO CENTRAL SOUTH DAKOTA LATE THIS AFTERNOON AND EARLY THIS EVENING
ALONG WITH WEAK PV ADVECTION ALOFT SO WILL NEED TO WATCH THIS AREA
FOR A LITTLE LIGHT SNOW FROM ABOUT 6 PM THROUGH 2 AM. WILL HAVE TO
OVERCOME QUITE A BIT OF DRY AIR IN THE WAKE OF YESTERDAYS SYSTEM SO
CONFIDENCE NOT EXCEEDINGLY HIGH ON ACCUMULATIONS. THINKING THAT THE
BETTER CHANCES FOR ACCUMULATIONS WILL BE TONIGHT AND MORE COUPLED
WITH FORCING FROM ABOUT 850-800MB WHERE THE BETTER DENDRITIC LAYER
RESIDES. WHILE LAYERS ABOVE...ESPECIALLY FROM ABOUT 700MB ON
UP...WILL BE QUITE DRY WE SHOULD BE STILL GET A LITTLE LIGHT SNOW
WITH THE FAVORABLE FORCING/THERMAL FIELDS IN THE LOW LEVELS. /08
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
LARGE AREA OF MVFR STRATUS SLOWLY SHIFTING EAST THIS MORNING...BUT
THE WESTERN EDGE FINALLY STARTING TO SHOW SIGNS OF DISSIPATION. WILL
KEEP FSD AND SUX WITHIN THE STRATUS THROUGH ABOUT 18-20Z THEN
EXPECTING MAINLY MID AND HIGH CLOUDS...VFR...THROUGH THE PERIOD. HON
WILLS SEE THE BEST CHANCE FOR A RETURN OF MVFR CEILINGS AFTER ABOUT
10Z AS COLDER AIR SURGES SOUTHWARD. SOME PATCHY LIGHT SNOW...MAINLY
VFR BUT SOME PATCHY MVFR...WILL ALSO BE POSSIBLE FROM ABOUT THE
JAMES VALLEY WEST WITH THE BETTER CHANCE FROM ABOUT 2Z THROUGH 10Z.
/08
&&
.PREV DISCUSSION.../ISSUED AT 311 AM CST/
LIGHT SNOW WHICH AFFECTED PORTIONS OF OUR AREA ON SATURDAY HAS
PUSHED INTO CENTRAL MINNESOTA AND CENTRAL IOWA VERY EARLY THIS
MORNING. BEHIND THE EXITING SYSTEM...A BROAD AREA OF STRATUS HAS
DEVELOPED ACROSS THE EASTERN DAKOTAS INTO EASTERN NEBRASKA...THOUGH
MODELS NOT PICKING UP ON THIS AT ALL. 06Z RUC 925 MB RH TIME SECTION
HINTING AT IT...AND HAS IT PULLING EASTWARD THROUGH THE
MORNING...EXITING OVER OUR FAR EAST BY 18Z. OTHERWISE...A RELATIVELY
QUIET DAY IN STORE...WITH CLOUDS INCREASING IN OUR WEST IN THE
AFTERNOON AS A WEAK SHORTWAVE DROPS SOUTHWARD ON A NORTHWESTERLY
UPPER LEVEL FLOW. NOT MUCH IN THE WAY OF DYNAMICS WITH THIS
FEATURE...BUT COULD SPIT OUT SOME VERY LIGHT SNOW IN OUR WEST BY
LATE THIS AFTERNOON INTO TONIGHT. TEMPERATURES A BIT TRICKY
TODAY IN BETWEEN CLOUD COVER...THOUGH WHAT IS MORE CERTAIN IS THAT
READINGS WILL NOT WARM A WHOLE LOT OVER SNOW COVERED AREAS...WITH
HIGHS GENERALLY IN THE MID 20S THROUGH NORTHWESTERN IOWA AND
PORTIONS OF SOUTHWESTERN MINNESOTA. TO THE WEST...WITH MORE SUN AND
BETTER MIXING IN A TRANSITIONING SOUTHWESTERLY LOW LEVEL
FLOW...HIGHS WILL REACH THE MID 30S ACROSS THE MUCH OF THE JAMES
RIVER VALLEY INTO SOUTH CENTRAL SOUTH DAKOTA.
WINDS WILL BECOME NORTHWESTERLY AND PICK UP FROM WEST TO EAST
TONIGHT IN A TIGHTENING GRADIENT AND COLD AIR ADVECTION BEHIND THE
EXITING SHORTWAVE AND SURFACE LOW/ASSOCIATED FRONTAL BOUNDARY. THE
WINDS AND CLOUD COVER WILL KEEP OVERNIGHT LOWS SOMEWHAT IN
CHECK...THOUGH WILL STILL DROP INTO THE TEENS...EXCEPT SINGLE DIGITS
OVER SNOW COVER.
COLDER AIR WILL CONTINUE TO FILTER INTO THE REGION ON MONDAY WITH A
SURFACE HIGH BUILDING INTO THE REGION. TEMPERATURES WILL NOT RISE
MUCH FROM EARLY MORNING LOWS...WITH HIGHS ONLY IN THE UPPER TEENS TO
LOWER 20S. SOUTHERLY FLOW RETURNS TO THE REGION ON TUESDAY BEHIND
THE EXITING HIGH...AND TEMPERATURES TRY TO WARM A BIT IN THE
WEST...INTO THE MID AND UPPER 20S...WHILE READINGS OVER SNOW COVERED
AREAS MAY ACTUALLY BE A LITTLE COOLER THAN MONDAYS HIGHS WITH LESS
MIXING...REMAINING ONLY IN THE UPPER TEENS.
EVEN WARMER ON WEDNESDAY AHEAD OF THE NEXT ARCTIC SURGE WHICH WILL
DIVE SOUTHWARD ON WEDNESDAY NIGHT AND THURSDAY. COULD GET A LITTLE
SNOW ALONG THE LEADING EDGE OF THIS SURGE/FRONTAL GRADIENT DURING
THAT TIME FRAME...THOUGH ANY SNOW SHOULD BE LIGHT. HIGHS ON
WEDNESDAY WILL BE IN THE UPPER 20S TO MID 30S...THEN DROP BACK TO
THE LOWER TO MID 20S ON THURSDAY. FRIDAY LOOKS TO BE THE COLDEST DAY
OF THE WEEK...WITH HIGHS MID TEENS TO AROUND 20...FOLLOWED BY SOME
WARMING ON SATURDAY. LOOKS TO REMAIN DRY BOTH DAYS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
244 PM CST SUN DEC 4 2011
...A BRIEF TRANSITION TO A WINTRY MIX POSSIBLE FAR NORTHWEST LATE
TONIGHT EARLY MONDAY...OTHERWISE JUST A COLD RAIN EXPECTED...
.DISCUSSION...
WIDESPREAD LIGHT TO MODERATE RAIN WITH ISOLATED/EMBEDDED
THUNDERSTORMS ARE CONTINUING THIS AFTERNOON SOUTHEAST OF A CISCO
TO DECATUR...TO GAINESVILLE LINE. MAIN DRIVING FORCE HAS BEEN
WARM ADVECTION/ISENTROPIC LIFT OVER A SHALLOW FRONTAL INVERSION
CURRENTLY OVER NORTH TEXAS. WILL CONTINUE THE HIGH RAIN CHANCES
ACROSS THE MAJORITY OF NORTH TEXAS TONIGHT AS THE NEXT STRONG
SHORTWAVE BEGINS TO APPROACH NORTH TEXAS. MODERATE RAIN IS
OCCURRING ACROSS THE EASTERN COUNTIES AND 1 TO 2 INCHES..WITH
LOCALIZED AMOUNTS ACROSS NORTHEAST COUNTIES POSSIBLY NEARING 3
INCHES...IS EXPECTED THROUGH MONDAY MORNING.
THE 850MB FRONT IS CURRENTLY SITUATED FROM NEAR LUBBOCK TO
OKLAHOMA CITY THIS AFTERNOON AND SHOULD PROGRESS
SOUTHWARD..REACHING OUR NORTHWEST COUNTIES BY DAYBREAK MONDAY
MORNING PER THE WRF AND HRRR MODELS. MODEL FORECAST SOUNDINGS FOR
THIS AREA HAVE SATURATION AT/ABOVE 800MB WITH THE THERMAL PROFILE
STRADDLING THE 0 DEG C ISOTHERM THROUGH THE MORNING HOURS MONDAY.
BOTH MODELS SHOW SOME DRY POCKETS...PARTICULARLY BELOW 850MB
WHICH SHOULD KEEP ANY PRECIPITATION VERY LIGHT WITH A VERY LIGHT
RAIN/SNOW MIX POSSIBLE.
THE SHORTWAVE DISTURBANCE PASSES EAST OF NORTH TEXAS MONDAY
AFTERNOON WITH SUBSIDENCE AND ISENTROPIC DOWNGLIDE IN ITS WAKE.
THIS PROCESS WILL RAPIDLY SHUT OFF MOST PRECIPITATION FROM WEST
TO EAST THROUGH TUESDAY EVENING WITH BRISK AND COLD CONDITIONS
CONTINUING THROUGH THE NIGHT TUESDAY. WITH THE POSITIVELY TILTED
UPPER TROUGH TO OUR WEST...PLENTY OF MID-HIGH CLOUDINESS SHOULD
REMAIN MONDAY NIGHT THROUGH WEDNESDAY MORNING. THE COMBINATION OF
MOSTLY CLOUDY SKIES AND CONTINUED CAA IN THE LOWER LEVELS WILL
MAINTAIN A COLD START TO THE FIRST HALF OF THE WEEK. STUBBORN
UPPER LOW WILL OPEN AND LIFT OUT TUES NIGHT AND WEDNESDAY MORNING
AS STRONG JET STREAK ROUNDS ITS BASE. MODELS SHOW SOME ELEVATED
LIFT AND SHALLOW SATURATED LAYER ACROSS THE NORTHERN HALF OF
NORTH TEXAS AS THE UPPER TROUGH LIFTS OUT. IT APPEARS A FEW
FLURRIES COULD OCCUR CLOSER TO THE RED RIVER...BUT WILL LEAVE OUT
FOR NOW UNTIL MOISTURE PROFILES ARE BETTER RESOLVED.
IN WAKE OF OUR UPPER TROUGH...BRIEF MID LEVEL HEIGHT RISES OCCUR
LATER WEDNESDAY INTO THURSDAY ALLOWING FOR A MOSTLY CLEAR
FORECAST. CHILLY NIGHTS AND COOL DAYS WILL BE THE RULE LATE WEEK.
ANOTHER REINFORCING COLD FRONT ARRIVES BY FRIDAY AND WILL KEEP THE
AREA COOL INTO NEXT WEEKEND...AS ZONAL FLOW ALOFT PREVAILS.
05/42
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 38 42 32 40 28 / 100 60 10 10 10
WACO, TX 42 44 32 42 28 / 100 60 10 10 10
PARIS, TX 39 43 34 44 28 / 100 80 20 10 10
DENTON, TX 37 41 29 40 25 / 80 40 10 10 10
MCKINNEY, TX 38 42 31 42 26 / 100 60 10 10 10
DALLAS, TX 39 43 33 42 27 / 100 60 10 10 10
TERRELL, TX 40 43 31 43 28 / 100 80 10 10 10
CORSICANA, TX 41 44 35 44 30 / 100 70 10 10 10
TEMPLE, TX 41 43 32 43 28 / 100 60 10 10 10
MINERAL WELLS, TX 34 41 25 41 24 / 70 40 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
82/05/42
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
224 PM CST SUN DEC 4 2011
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DOUBLE
BARRELED LOW PRESSURE MOVING ACROSS THE ONTARIO-QUEBEC BORDER AND
THE STRAITS OF MACKINAC...AND A COLD FRONT STRETCHING FROM NORTHERN
LOWER MICHIGAN TO THE SOUTHERN MISSISSIPPI VALLEY. WITH NORTHWEST
FLOW IN PLACE AND DELTA T/S INCREASING TO 14C...CLOUD COVER HAS BEEN
STUBBORN TO DISSIPATE THOUGH PRECIP HAS EXITED TO THE NORTHEAST BY
MIDDAY. A SURFACE TROUGH IS TRYING TO DEVELOP OVER NORTHEAST AND CENTRAL
WISCONSIN THIS AFTERNOON AND A FEW SNOW SHOWERS/FLURRIES HAVE
DEVELOPED OVER THE PAST HOUR. SOME CLEARING NOTED OVER NORTHERN
MINNESOTA WHERE DEWPOINTS HAVE FALLEN TO THE LOWER TEENS. WITH
NORTHERLY FLOW IN PLACE OVER THE NEXT 24 HOURS...SMALL PRECIP
CHANCES AND CLOUD TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT... AS HIGH PRESSURE BUILDS OVER THE NORTHERN PLAINS...WEAK
CYCLONIC FLOW WILL LINGER ACROSS THE REGION. LOW LEVEL FLOW WILL
VEER FROM THE NORTHWEST TO THE NORTH...WHICH WILL KEEP MOISTURE
STREAMING OFF LAKE SUPERIOR. AS A RESULT...SCT LAKE EFFECT SNOW
SHOWERS WILL PREVAIL OVER THE SNOW BELT OF N-C WISCONSIN FOR THE
ENTIRE NIGHT. FARTHER SOUTH...A WEAK SURFACE TROUGH WILL MOVE SOUTH
OVER CENTRAL WISCONSIN THIS EVENING. MOISTURE DEPTH WILL EXTEND
BEYOND 800MB AND -10C...SO IT SEEMS PLAUSIBLE THAT FLURRIES OR VERY
LIGHT SNOW SHOWERS ARE POSSIBLE ALONG THE TROUGH. HAVE ADDED
SLIGHTLY MORE TEMPORAL RESOLUTION TO ACCOUNT FOR THIS.
OTHERWISE...DO NOT SEE MUCH OF AN OPPORTUNITY FOR CLEARING...EXCEPT
IN THE DOWN SLOPING REGIONS OF NORTHEAST WISCONSIN WHERE SOME HOLES
MAY DEVELOP...ESPECIALLY LATE TONIGHT. LOWS IN THE UPPER TEENS
NORTH TO UPPER 20S SOUTHEAST.
MONDAY...ONLY SOME SUBTLE CHANGES HEADING INTO MONDAY. SHORTWAVE
ENERGY OVER THE PLAINS WILL LIFT TO THE NORTHEAST OVER NW
WISCONSIN...BUT WITH VERY LITTLE IMPACT ON OUR WEATHER. WILL
CONTINUE TO HAVE NORTHERLY FLOW TOMORROW WITH SOME MINOR COLD
ADVECTION THAT WILL DROP 850MB TEMPS IN THE NEGATIVE LOW TO MID
TEENS. LIGHT LAKE EFFECT SNOW SHOWERS WILL PREVAIL OVER THE SNOW
BELT OF N-C WISCONSIN...WHILE MOSTLY CLOUDY CONDITIONS WILL BE THE
RULE ELSEWHERE. HIGHS IN THE MIDDLE 20S NORTH TO MIDDLE 30S
SOUTHEAST.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...THE MAIN FCST
CONCERN IS THE ARRIVAL OF COLDER ARCTIC AIR LATE IN THE NEXT WORK
WEEK.
A STRONG UPPER RIDGE WILL COVER THE EASTERN PACIFIC...SOUTHWEST
CANADA AND THE WEST COAST OF THE U.S. EARLY IN THE PERIOD...WITH A
POSITIVELY-TILTED UPPER TROF MOVG OUT OF THE NORTHERN PLAINS INTO
THE WESTERN GREAT LAKES. THIS UPPER TROF WILL MOVE THROUGH
WISCONSIN ON MONDAY NIGHT AND TUESDAY...BUT WITH A SFC RIDGE OF
HIGH PRESSURE IN PLACE...EXPECT MINIMAL IMPACT ON OUR WEATHER.
SHORT-WAVE ENERGY TOPPING THE WESTERN RIDGE AND DIVING INTO THE
NORTHERN PLAINS WILL HELP TO CARVE A BROAD TROF OVER THE CENTRAL
U.S. BY THURSDAY. A SURGE OF ARCTIC AIR IS EXPECTED TO ARRIVE IN
WI ON THURSDAY...WITH H8 TEMPS PLUMMETING TO AROUND -20 C LATE
THURSDAY NIGHT INTO FRIDAY. THIS WILL LEAD TO OUR COLDEST
TEMPERATURES SO FAR THIS SEASON. THE COLD SNAP WILL BE BRIEF...
AS SOUTHWEST WINDS DEVELOP IN THE WAKE OF THE RETREATING ARCTIC
HIGH OVER THE WEEKEND.
A LARGE RIDGE OF HIGH PRESSURE WILL BUILD INTO NW WI ON MONDAY
NIGHT...THEN MOVE THROUGH GRB CWA ON TUESDAY. LINGERING LAKE-EFFECT
SNOW SHOWERS OVER NC WI SHOULD COME TO AN END AS THE RIDGE AXIS
ARRIVES ON TUESDAY.
A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION ON
WEDNESDAY...WITH A STRONGER ARCTIC FRONT ARRIVING ON THURSDAY.
THE ECMWF HAS BACKED OFF ON THE POTENTIAL FOR SNOW ALONG THE
ARCTIC FRONT ON THU NGT/FRI...AND IS FOCUSING FARTHER SE...FROM
SOUTHERN WI INTO LOWER MICHIGAN. WILL NEED TO KEEP AN EYE ON THIS
OVER THE NEXT FEW DAYS TO SEE IF THIS TREND WILL HOLD. CONFIDENCE
IS FAIRLY HIGH FOR THE ARRIVAL OF MUCH COLDER TEMPERATURES LATE IN
THE WORK WEEK...ALTHOUGH THE COLD IS EXPECTED TO BE SHORT-LIVED.
A WARM FRONT IS EXPECTED TO ARRIVE ON SUNDAY...WITH TEMPERATURES
CLIMBING BACK TO ABOVE NORMAL.
DESPITE THE PRESENCE OF A COLD AIR MASS FROM WEDNESDAY THROUGH
SATURDAY...WIND TRAJECTORIES WILL NOT BE FAVORABLE FOR LK-EFFECT
SNOW.
&&
.AVIATION...CYCLONIC FLOW VEERING FROM NORTHWEST TO NORTH WILL BE
PREVAILING ACROSS THE REGION THROUGH TOMORROW. WITH FLOW OFF LAKE
SUPERIOR...WILL BE HARD PRESSED TO SEE SOME CLEARING OVER THE TAF
SITES. SOME HOLES WILL LIKELY DEVELOP OVER THE FOX VALLEY WITH
TEMPORARY VFR CIGS...BUT MVFR CIGS WILL PREVAIL THROUGH LATE
TONIGHT. SOME SNOW SHOWERS/FLURRIES WILL OCCASIONALLY IMPACT
RHI...AND POSSIBLY AUW/CWA THIS EVENING WHEN A WEAK SURFACE TROUGH
DROPS SOUTH. SOME MINOR IMPROVEMENT OF CIGS EXPECTED ON MONDAY.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/KIECKBUSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1141 AM CST SUN DEC 4 2011
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
324 AM CST SUN DEC 4 2011
MAIN FORECAST CONCERN NOW THAT THE PRECIPITATION IS
EXITING/DIMINISHING IS WHEN CLOUDS WILL CLEAR.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING STILL OVER THE EAST PACIFIC AND ALONG THE EAST COAST
OF THE U.S....AND TROUGHING IN-BETWEEN FROM HUDSON BAY SOUTHWEST
INTO ARIZONA. IMPORTANT FEATURES TO NOTE INCLUDE A SHORTWAVE NEAR
EAU CLAIRE WI ON THE EAST SIDE OF THE UPPER TROUGH...AND TWO
SHORTWAVES OVER MONTANA ON THE BACK SIDE OF THE UPPER TROUGH. THE
FORMER SHORTWAVE IN CONJUNCTION WITH PLENTIFUL MOISTURE AND LOW TO
MID-LEVEL FRONTOGENESIS BROUGHT THE WIDESPREAD PRECIPITATION TO THE
AREA LAST NIGHT. DRY SLOT NOTED IN WATER VAPOR COMBINED NOW WITH THE
SHORTWAVE MOVED THROUGH...RESULTING IN SOME SUBSIDENCE...HAS ALLOWED
PRECIPITATION TO REALLY DIMINISH DURING THE PAST 4-6 HOURS. IT
APPEARS MODELS YESTERDAY MAY HAVE OVERDONE THE LOW LEVEL ISENTROPIC
LIFT FOR THE CURRENT EARLY MORNING HOURS... GIVEN THAT THEY NOW SHOW
NO ISENTROPIC LIFT AND SEEING THE PRECIPITATION DIMINISH ON RADAR.
THEREFORE...THE CONCERN ABOUT THE DRY SLOT CLEARING OUT ICE AND
RESULTING IN FREEZING PRECIPITATION IS NOT AS GREAT. IN ADDITION...
SURFACE TEMPERATURES HAVE STRUGGLED TO FALL BELOW FREEZING WHERE IR
CLOUD TOP TEMPERATURES INDICATE ICE HAS BEEN LOST. REGARDING THE
SURFACE...SEA LEVEL PRESSURE ANALYSIS SHOWS A 1008MB LOW NEAR
MANITOWOC WI. PLENTY OF CLOUDS EXTEND WEST FROM THE LOW...BACK
INTO THE EASTERN DAKOTAS. UPSTREAM...ANOTHER BUT MUCH WEAKER SURFACE
LOW IS NOTED NEAR WILLISTON ASSOCIATED WITH ONE OF THE MONTANA
SHORTWAVES.
TODAY AND TONIGHT...A SHORTWAVE IN EASTERN MONTANA IS PROGGED TO
MOVE INTO SOUTH DAKOTA TODAY AND INTO NORTHWEST WISCONSIN TONIGHT.
THE TRACK OF THE SHORTWAVE SUGGESTS ALL OF THE FORCING WILL STAY
NORTH AND WEST OF THE AREA. THIS IS CONFIRMED TOO BY QG PLOTS. IN
ADDITION...IT APPEARS MUCH OF THE CLOUD COVER ASSOCIATED WITH THE
SHORTWAVE WILL STAY TO THE NORTHWEST. SO THIS LEAVES THE CURRENT
CLOUD COVER AND SYSTEM GOING THROUGH THE MAIN CONCERN. WITH STRATUS
EXTENDING SO FAR WEST...GRADUAL SUBSIDENCE OCCURRING TODAY IN THE
WAKE OF THE SYSTEM AND THE LOW SUN ANGLE...THINKING A VERY
PESSIMISTIC TREND MIGHT BE THE WAY TO GO. LIKE THE 04.00Z NAM
INDICATING THE STRATUS STAYS IN PUT ACROSS THE AREA TODAY WITH ONLY
SLOW CLEARING TONIGHT FOR WESTERN AREAS. CONCERNED THAT EVEN THE NAM
MIGHT BE TOO FAST TONIGHT AS THE 900-950MB WINDS TURN FROM THE
NORTHWEST TO NORTH. COMBINED WITH THE RECENT MOISTURE...CLOUDS MAY
ACTUALLY LOWER IN CEILING HEIGHT VERSUS CLEARING. LAST CONCERN IS
PRECIPITATION...BOTH THIS MORNING AND POSSIBLY OUT OF THE STRATUS
DECK TONIGHT. GIVEN DIMINISHING RADAR RETURNS AND DRY FORECASTS
INDICATED BY THE 04.00Z NAM/GFS/ECMWF FOR 12-18Z TODAY...HAVE REALLY
DRIED OUT THIS MORNING. IN FACT...THERE MAY NOT BE MUCH GOING ON
AFTER 12Z. WITH PRECIPITATION RAPIDLY DIMINISHING...WILL CANCEL THE
ADVISORY HERE AT 4 AM. TONIGHT...THE 04.00Z NAM/GFS SHOW SOME LIGHT
QPF OVER THE NORTH HALF OF WISCONSIN. APPEARS TO RESULT FROM LOW
LEVEL CONVERGENCE...ASSOCIATED WITH SURFACE TROUGHING LINGERING BACK
FROM THE CURRENT AREA OF LOW PRESSURE NEAR GRB. HAVE ADDED A 20
PERCENT CHANCE OF SNOW INTO THE FORECAST TO ACCOUNT FOR THIS
POSSIBILITY. OTHERWISE...TEMPERATURES LOOK LIKE THEY SHOULD STRUGGLE
TO RISE TODAY WITH 850MB TEMPS FALLING TO AT LEAST -6 TO -8C AND
CLOUDS STAYING PUT. MAYBE A 1 OR 3 DEGREE F RISE IS POSSIBLE FROM
THE 6 AM TEMPERATURE. WITH MORE CLOUDS ANTICIPATED TONIGHT...BROUGHT
LOW TEMPERATURES UP A FEW DEGREES...ESPECIALLY ALONG AND EAST OF THE
MISSISSIPPI RIVER WHERE CLOUDS ARE MORE CERTAIN. WHERE CLOUDS CLEAR
OUT...TEMPERATURES COULD FALL INTO THE UPPER SINGLE DIGITS.
MONDAY THROUGH TUESDAY NIGHT...BIG STORY/CONCERN HERE IS FORECASTING
WHEN THE STRATUS WILL DISSIPATE AND ANY POTENTIAL PRECIPITATION OUT
OF IT. UPPER TROUGH SITUATED OVER THE NORTHERN PLAINS IS FORECAST TO
MARCH SOUTHEAST DURING THIS PERIOD...IN RESPONSE TO A POWERFUL UPPER
TROUGH DIGGING FORMING OVER CENTRAL CANADA. NORTH TO NORTHEAST LOW
LEVEL FLOW IS LIKELY MONDAY INTO MONDAY NIGHT WITH HIGH PRESSURE
BUILDING INTO THE NORTHERN PLAINS. THIS FLOW SHOULD DO A DECENT JOB
IN HOLDING IN THE STRATUS BELOW THE SUBSIDENCE INVERSION...UNTIL
MAYBE LATE MONDAY NIGHT WHEN THERE IS SUGGESTION THE FLOW BACKS
NORTHWEST TO BRING IN SOME DRIER LOW LEVEL AIR. IN ADDITION...THAT
TROUGH MENTIONED IN THE TONIGHT DISCUSSION IS PROGGED TO DROP
SOUTHWEST DUE TO THE LOW LEVEL FLOW. CONVERGENCE ALONG THIS TROUGH
COULD RESULT IN SOME FLURRY ACTIVITY AND HAVE ADDED IT TO THE
FORECAST. 04.00Z CANADIAN MODEL IS EVEN MORE AGGRESSIVE AND SHOWING
A FEW HUNDREDTHS. IF OTHER MODELS...SUCH AS THE NAM/GFS START TO
SHOW THIS IN LATER RUNS...MAY NEED TO HAVE SOME HIGHER CHANCES
ADDED. BETTER POTENTIAL FOR CLEARING EXISTS TUESDAY AS THE SURFACE
RIDGE MOVES IN AT THE SAME TIME WITH DAYTIME HEATING...SO INDICATED
CLEARING STARTING HERE. UPPER RIDGING THEN BUILDS OVER THE AREA FOR
TUESDAY NIGHT AHEAD OF THE POWERFUL UPPER TROUGH...MAINTAINING DRY
CONDITIONS WITH GENERALLY MOSTLY CLEAR SKIES. FOR TEMPERATURES...
LOOK FOR A COOLING TREND AS THE UPPER TROUGH MOVES IN. DID RAISE LOW
TEMPERATURES UP MONDAY NIGHT IN THE CLOUDY SKY AREA...CLOSER TO THE
2 METER NAM12 GUIDANCE. OTHERWISE...A BLEND OF GUIDANCE SEEMED
REASONABLE.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
324 AM CST SUN DEC 4 2011
AFTER WHAT WAS SOME UNCERTAINTY IN THE LONG TERM FORECAST...CAUSED
ESPECIALLY BY THE 03.12Z ECMWF SUGGESTING A POSSIBLE ADVISORY-TYPE
SNOW MOVING THROUGH FRIDAY/FRIDAY NIGHT...ALL MODELS HAVE COME BACK
INTO GREAT AGREEMENT ON THE UPPER AND SURFACE PATTERNS THROUGHOUT
THE LONG TERM. IN FACT...THEY LOOK A LOT LIKE WHAT WAS SHOWN BY THE
03.00Z CYCLE. SO FOR NOW WILL CONSIDER THE 03.12Z ECMWF AN ODD
OUTLIER. A WEST-NORTHWEST FLOW UPPER PATTERN BEGINS THE LONG
TERM...ON THE SOUTH SIDE OF THE POWERFUL TROUGH DROPPING INTO
SOUTHERN CANADA. A COLD FRONT LOOKS TO SLIDE THROUGH THE FORECAST
AREA ON WEDNESDAY...ENDING A BRIEF WARM SURGE ALOFT CAUSED BY THE
UPPER RIDGE. THEN FOR WEDNESDAY NIGHT AND THURSDAY...A SHORTWAVE
TROUGH IS FORECAST TO DIG DOWN THE WEST SIDE OF THE CANADA UPPER
TROUGH...CAUSING AN UPPER JET TO STRENGTHEN DOWNSTREAM OVER NORTHERN
WISCONSIN. RIGHT ENTRANCE REGION FORCING OF THIS JET SHOULD INDUCE
SOME MID-LEVEL FRONTOGENESIS...AND COMBINED WITH A LITTLE MOISTURE
MAY PRODUCE A BAND OF LIGHT SNOW OVER FAR SOUTHERN SECTION THURSDAY
NIGHT. INCLUDED A 20 PERCENT CHANCE FOR THIS. BIGGER IMPACT IS ON
FRIDAY WHEN THE SHORTWAVE TROUGH MOVES ACROSS...CAUSING 850MB TEMPS
TO TANK FROM -9 TO -13C ON THURSDAY TO AROUND -20C ON FRIDAY.
NEEDLESS TO SAY...BELOW NORMAL TEMPERATURES LIKELY. A DRY AND SLOW
WARMING TREND SHOULD THEN ENSUE HEADING INTO THE WEEKEND IN RESPONSE
TO THE MODELS FORECASTING THE UPPER FLOW BECOMING MORE ZONAL. IN
FACT...THE LATEST 04.00Z ECMWF SUGGESTS HIGHS APPROACHING 40 FOR
NEXT SUNDAY AS A SURGE OF DOWNSLOPED WARMED PACIFIC AIR FLOWS INTO
THE AREA.
&&
.AVIATION...THROUGH 18Z MONDAY
1141 AM CST SUN DEC 4 2011
LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION WILL CONTINUE TO
PRODUCE MAINLY MVFR CEILINGS AT THE TAF SITES THROUGH LATE
TONIGHT...WITH CEILINGS IN THE 1000 TO 1500 FT RANGE. AN UPPER
LEVEL SHORTWAVE MOVING ACROSS THE AREA MAY PRODUCE SOME FLURRIES
ACROSS THE TAF SITES AS IT MOVES THROUGH DURING THE EVENING AND
OVERNIGHT HOURS. FORECAST SOUNDINGS SHOW A SMALL POSSIBILITY OF
LOSING ICE ALOFT...WHICH COULD LEAD TO LIGHT FREEZING DRIZZLE.
CONFIDENCE LOW ON THIS OCCURRING SO HAVE NOT INCLUDED IT IN THE
TAFS AT THIS TIME. PLAN ON MVFR CONDITIONS AT KLSE THROUGH THE
FORECAST PERIOD. THE STRATUS IS EXPECTED TO BECOME BKN TO SCT AT
KRST AROUND 08Z TONIGHT...WHICH MAY PROVIDE A PERIOD OF VFR
CONDITIONS LATE TONIGHT INTO EARLY MONDAY MORNING. LOOK FOR
NORTHWEST WINDS AT 6 TO 10 KTS THROUGH THE FORECAST PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
324 AM CST SUN DEC 4 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....WETENKAMP