Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 11/30/11
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1005 PM EST TUE NOV 29 2011
.SYNOPSIS...
LOW PRESSURE WILL TRACK DOWN THE SAINT LAWRENCE RIVER VALLEY
OVERNIGHT...WITH AN ASSOCIATED OCCLUDED FRONT CROSSING THE TRI-STATE
AS A RESULT. THE LOW THEN CONTINUES TO MOVE DOWN THE SAINT
LAWRENCE RIVER VALLEY INTO WEDNESDAY NIGHT. HIGH PRESSURE BUILDS
IN THURSDAY AND FRIDAY. A WEAK COLD FRONT WILL MOVE ACROSS THE
REGION FRIDAY NIGHT INTO SATURDAY WITH HIGH PRESSURE BUILDING BACK
INTO THE REGION FROM LATE SATURDAY THROUGH MONDAY. LOW PRESSURE
THEN APPROACHES THE AREA MONDAY THROUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AT 2Z OCCLUDED FRONT WAS JUST INTO FAR WESTERN ZONES...AND MAKING VERY
SLOW PROGRESS EASTWARD...AS A RESULT HAVE SLOWED DOWN TIMING FOR THE END
OF THE STEADIER RAINFALL. WITH ALL LIGHTNING WITH THIS SYSTEM SO
FAR CONFINED TO MI TO THE NNW OF UPPER LOW AND WELL OFF NJ COAST -
SE OF BUOY 44066...HAVE GONE AHEAD AND REMOVED THUNDER FROM
FORECAST. BASICALLY EXPECT TO SEE PERIODS OF MODERATE RAIN THROUGH
MOST OF THE NIGHT...TAPERING OFF FROM W TO E TOWARDS MORNING.
WITH SLOWER FRONTAL TIMING...HAVE ADJUSTED TEMPERATURE FALL OFF
OVER THE REGION SLOWER...WITH A BLEND OF NAM 2-METER/HRRR
TEMPERATURES...AND THE LATEST GUIDANCE - MET/MAV/LAV. FOR NOW IT
APPEARS FRONT WILL MOVE THROUGH BEFORE MIDNIGHT...SO MAX MIN
RECORDS SHOULD BE SAFE. HAVE INCLUDED THEM IN THE CLIMATE SECTION
OF THE AFD IN CASE THE FRONT MOVES SLOWER THAN EXPECTED - GOING
FAIRLY CLOSE TO 18Z-NAM/23Z HRRR TIMING RIGHT NOW.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
CLOSED LOW SHEARS NE FROM THE EASTERN GREAT LAKES ON WED THROUGH THE
ST LAWRENCE RIVER VALLEY WED NIGHT.
AFTER ANY LINGERING SHRA OVER FAR EASTERN ZONES EARLY WEDNESDAY
MORNING...REGION WILL REMAIN IN DRY SLOT ON WED AS SHORTWAVE ENERGY
SHEARS NE WHILE SLIDING TO THE COAST. THIS SHOULD MAINTAIN
GENERALLY DRY CONDITIONS...WITH SCT-BKN INSTABILITY CU. AN
ISOLATED SHOWER/SPRINKLE IS POSSIBLE ACROSS FAR NW SECTIONS...BUT
NOT ENOUGH COVERAGE TO WARRANT POPS. TEMPS WILL FEEL MORE FALL
LIKE WITH GUSTY WSW WINDS AND CAA FLOW HOLDING TEMPS IN THE LOWER
50 INTERIOR...MID 50S COAST. THIS IS STILL A FEW DEGREES ABOVE
NORMAL THOUGH.
SHEARING SHORTWAVE ENERGY AND WEAK SURFACE TROUGH MOVE ACROSS THE
REGION WED NIGHT. AGAIN THIS SHOULD BE A MAINLY DRY PASSAGE...WITH
GRADUALLY CLEARING SKIES IN ITS WAKE. GUSTY NW WINDS WILL CONTINUE
TO DROP TEMPS TO NEAR SEASONABLE...UPPER 30S CITY/COAST...UPPER
20S/LOWER 30S COAST.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
PERIOD BEGINS WITH HIGH PRESSURE BUILDING IN FROM THE SOUTH AND
ZONAL FLOW ALOFT WITH LIGHT WINDS AND MOSTLY CLEAR SKIES.
TEMPERATURES WILL REMAIN NEAR NORMAL FOR THURSDAY AND FRIDAY. A
SHARP UPPER TROUGH SWEEPS THROUGH FRIDAY NIGHT WITH A WEAK COLD
FRONT. WITH DOWN SLOPING NORTHWEST WINDS AND LITTLE MOISTURE...NO
PRECIPITATION IS EXPECTED...JUST SOME MID LEVEL STRATO CU WITH THE
FRONT. A BRIEF SHOT OF COLD AIR WILL FOLLOW THIS FRONT WITH
TEMPERATURES SLIPPING A FEW DEGREES BELOW NORMAL ON SATURDAY.
HIGH PRESSURE BUILDS BACK IN FROM THE OHIO VALLEY THROUGH THE
WEEKEND WITH RIDGING ALOFT. TEMPERATURES RISE BACK TO NEAR NORMAL
SATURDAY AND SUNDAY WITH CIRRUS SPILLING OVER THE RIDGE.
NEXT POTENTIAL ISSUE WILL BE THE MON-WED TIME FRAME WITH GFS/ECMWF
BOTH HINTING AT A DEEP TROUGH DEVELOPING OVER THE MIDWEST AND A SFC
LOW DEVELOPING NEAR PA. BOTH SHOW PRECIPITATION IN THIS TIME FRAME
ASSOCIATED WITH THIS LOW PRESSURE AREA BUT KEPT POPS AT CHANCE
BECAUSE TIMING COULD CHANGE SIGNIFICANTLY IN THE NEXT FEW DAYS.
ECMWF THEN SHOWS THE UPPER LOW CUTTING OFF OVER NORTHERN NY AND A
SURFACE LOW DEEPENING OFF THE SOUTHERLY MAINE COAST WITH THE GFS
DEVELOPING THIS LOW MUCH FARTHER NORTH. DEPENDING ON THE EXACT TRACK
OF THIS SYSTEM...WINDS WILL PICK UP TUESDAY EVENING AND SNOW IS
POSSIBLE BEHIND THIS SYSTEM. TOO UNCERTAIN AT THIS POINT TO PUT MORE
THAN A CHANCE/SLIGHT CHANCE POPS FOR THIS SYSTEM.
TEMPS REMAIN NEAR NORMAL ON MONDAY AND DROP TO BELOW NORMAL ON
TUESDAY WITH LOWS NEAR TO BELOW FREEZING IN MOST AREAS TUESDAY NIGHT.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
AN OCCLUDED FRONT WILL CONTINUE MOVING EAST ACROSS EASTERN CT AND
EASTERN LONG ISLAND DURING THE NEXT FEW HOURS.
SOUTHEAST WINDS SHIFTED TO THE SOUTHWEST EARLIER THAN FORECAST AND
RESULTED IN HIGHER CIGS AND VSBY FROM THE NYC METRO AREA N AND W.
RAIN WILL CONTINUE MVG NE AND END BETWEEN 06Z AND 09Z FROM SW TO
NE.
SW WINDS WILL RANGE FROM 15-20 KT WITH GUSTS OF 20-25 KT AREA WIDE
THROUGH THE DAY ON WEDNESDAY.
A WEAK COLD FRONT WILL CAUSE SW WINDS TO SHIFT TO THE NW AFTER
SUNSET WED AT SPEEDS BETWEEN 15 AND 20 KT AREA WIDE.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
WED NIGHT: VFR. NW WINDS 15-20 WITH GUSTS 20-25 KT.
THU-SUN...VFR.
&&
.MARINE...
SCA SE WINDS...WITH GUSTS UP TO 30 KT...EXPECTED AHEAD OF
OCCLUDED FRONT. SEAS EXPECTED TO CONTINUE BUILDING TO NEAR 7 TO
10 FT BY WEDNESDAY MORNING.
WINDS GRADUALLY SUBSIDE TO MARGINAL SCA BY WED MORNING AND CONTINUE
AS SUCH INTO WED NIGHT. OCEAN SEAS WILL ONLY SLOWLY SUBSIDE
THOUGH WITH THESE STRONG WINDS...LIKELY REMAINING SCA ON EASTERN
OCEAN WATERS...THROUGH WED NIGHT.
PERSISTENT WNW FLOW COULD MAINTAIN 5 FT SEAS INTO THURSDAY MORNING
WITH WINDS SUBSIDING AS HIGH PRESSURE BUILDS IN. WAVES WILL CONTINUE
TO DROP THROUGHOUT THE DAY THURSDAY AND REMAIN BELOW SCA CRITERIA.
WITH A COLD FRONT PASSAGE ON FRIDAY...SEAS ON THE EASTERN OCEAN
WATERS MAY PRODUCE SCA SEAS WHICH WILL LIKELY PERSIST THROUGH
SATURDAY. HIGH PRESSURE BUILDS IN ON SUNDAY WITH SEAS AND WINDS
BELOW SCA CRITERIA.
&&
.HYDROLOGY...
EXPECTING GENERALLY 1/2" TO 3/4" THROUGH TONIGHT...WITH LOCALLY
HIGHER AMOUNTS COINCIDENT WITH BANDING LOCATION. ONLY LOCALIZED
MINOR URBAN AND POOR DRAINAGE FLOODING EXPECTED.
&&
.CLIMATE...
RECORD HIGHEST MINIMUM TEMPERATURES (MAX MINS)
FOR TODAY - NOVEMBER 29TH
RECORD YEAR
CENTRAL PARK 58 2005
LAGUARDIA 60 2005
KENNEDY 56 2005
NEWARK 57 2005
ISLIP 57 2005
BRIDGEPORT 52 2005
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR ANZ330-335-
338-340-345-350-353-355.
&&
$$
SYNOPSIS...MALOIT/NV/LN
NEAR TERM...MALOIT
SHORT TERM...MALOIT/NV
LONG TERM...LN
AVIATION...GTC
MARINE...MALOIT/NV/LN
HYDROLOGY...NV
CLIMATE...JM
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1234 AM EST MON NOV 28 2011
.SYNOPSIS...
HIGH PRESSURE REMAINS OFFSHORE TO THE EAST MONDAY WHILE A LOW
PRESSURE SYSTEM TRACKS EAST ACROSS CANADA...DRAGGING A COLD FRONT
THROUGH NEW ENGLAND. A STORM SYSTEM WILL SLOWLY TRACK FROM THE UPPER
OHIO RIVER VALLEY TO THE CANADIAN MARITIME PROVINCES BY THURSDAY
MORNING. WEAK HIGH PRESSURE BUILDS IN THURSDAY AND THURSDAY
NIGHT...FOLLOWED BY A WEAK COLD FRONT ON FRIDAY. HIGH PRESSURE
THEN BUILDS IN FOR THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
0440Z UPDATE...FORECAST ON TRACK...SO ONLY MINOR CHANGES TO NEXT
COUPLE OF HOURS MADE TO THE DATABASE. WITH WEAK WARM ADVECTION AND
INCREASING CLOUDS...LOWS TONIGHT WILL GENERALLY BOTTOM OUT IN THE
LOW TO MID 50S...AND POSSIBLY INTO THE LOWER 40S ACROSS FAR NW
ZONES.
OTHERWISE...WATER VAPOR SHOWS A DEEP LAYERED RIDGE...WITH THE
RIDGE AXIS TO OUR SW...AND GUIDANCE SUGGESTS THE STATUS QUO WILL
MAINTAIN ITSELF THROUGH TONIGHT. THE RESULT IS MINIMAL IF ANY
FORCING...SO HAVE REMOVED ALL PRECIPITATION FROM TONIGHT. UPDATED
POPS ARE CONSISTENT WITH A BLEND OF HRRR HOURLY AND SREF AND NAM
3-HOUR POPS - WEIGHED MORE TOWARDS THE HRRR IN THE FIRST SIX HOURS
OR SO.
STILL APPEAR ON TRACK FOR FOG OR MORE LIKELY STRATUS TO DEVELOP
OVERNIGHT. QUESTION IS WILL THE FOG BECOME DENSE OR...WILL
ULTIMATELY LOW LEVEL STRATUS WIN OUT. FOR NOW BEGINNING TO LEAN
MORE TOWARDS THE STRATUS BASED ON BUFKIT PROFILES...BUT NOT
CONFIDENT ENOUGH TO REMOVE FOG FROM ZONES AT THIS TIME. HOWEVER IF
THE FOG WINDS OUT...WILL LIKELY SEE DENSE FOG...EVEN MORE
WIDESPREAD THEN LAST NIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THE LIGHT RAIN/DRIZZLE OVER FAR NW ZONES WILL REMAIN POSSIBLE
THROUGH AROUND 16Z BEFORE THINGS DRY UP FOR THE REST OF THE
PERIOD. HIGH PRESSURE REMAINS TO THE EAST...WITH TWO LOW PRESSURE
SYSTEMS BECOMING THE NEXT FOCUS. THE ONE LOW MOVING THROUGH CANADA
WILL DRAG A COLD FRONT THROUGH NORTHERN NEW ENGLAND. CURRENT
GUIDANCE INDICATES THE FRONT WILL REMAIN NORTH OF THE AREA...AND
THUS SHOULDN/T AFFECT THE CWA. THE SECOND LOW FORMS OVER THE
SOUTHEASTERN US MONDAY MORNING AND PUSHES NORTH THROUGH THE
DAY...SETTLING OVER TN AND KY FOR MON NIGHT. THE UPPER LEVEL RIDGE
WILL BEGIN WEAKENING AS WELL MONDAY...AHEAD OF A DEVELOPING UPPER
LEVEL LOW OVER THE MIDWEST.
SOUTHWESTERLY FLOW WILL PERSIST THROUGH MONDAY...WITH THE WINDS
SHIFTING BACK TO A SOUTHERLY FLOW FOR MON NIGHT. SIDED MORE WITH
A GFS/MOS MIX FOR GUIDANCE FOR WINDS DURING THIS PERIOD AS THE NAM
BRINGS THE WINDS AROUND TO THE EAST MUCH QUICKER...BY 12Z TUES
MORNING. CURRENT THINKING WILL BE THE LOW IS SLIGHTLY SLOWER...AND
THE WINDS WILL BE MORE SOUTHEASTERLY BY 12Z TUES MORNING. THE NAM
ALSO WANTS TO HAVE THE HIGH PRESSURE MORE DOMINANT MON NIGHT...SO
SIDED WITH THE WEAKER HIGH WITH THE GFS. WITH THE GFS
TIMING...BROUGHT IN A SLIGHT CHANCE FOR POPS LATE IN THE PERIOD MON
NIGHT FOR THE FAR WESTERN PORTION OF THE CWA. WITH THE LOWER LEVEL
MOISTURE REMAINING ELEVATED...HAVE ALSO INCLUDED PATCHY FOG AROUND
THE CWA FOR MON NIGHT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
GFS IN GENERAL TOO PROGRESSIVE AS HAS BEEN ITS BIAS OF LATE...SO
USED A NAM/ECMWF/SREF BLEND TUESDAY-WEDNESDAY...THEN FOLLOWED THE
ECMWF WEDNESDAY NIGHT-SUNDAY.
UPPER RIDGE AXIS OVER THE REGION SUPPORTS DAMMING HIGH SIGNATURE
OVER THE REGION TUESDAY INTO TUESDAY NIGHT. THIS WILL HELP TO SERVE
TO IMPEDE PROGRESS OF PRECIPITATION INTO THE REGION AHEAD OF CUTOFF
SYSTEM MOVING INTO THE WEST-CENTRAL APPALACHIANS BY TUESDAY EVENING.
AS A RESULT ONLY BRING POPS UP TO LIKELY OVER WESTERN 1/5 OF CWA AND
JUST BARELY TO CHANCE OVER FAR EASTERN PARTS OF THE CWA BY LATE
AFTERNOON.
STRONG ISENTROPIC LIFT DEVELOPS TUESDAY NIGHT...ALONG WITH 50-60 KT
LOW LEVEL JET IMPACTING REGION...ALLOWING FOR MODERATE TO POSSIBLY
LOCALLY HEAVY RAINFALL TO DEVELOP ACROSS THE TRI-STATE TUESDAY
NIGHT. WITH SHOWALTERS 0 TO -2...HAVE ADDED SLIGHT CHANCE OF THUNDER
TO ALL AREAS EAST OF THE HUDSON PLUS MOST OF NE NJ. CATEGORICAL POPS
THROUGHOUT TUESDAY NIGHT (DEVELOP FROM W TO E).
SHOWERS SHOULD TAPER OFF FROM W TO E MAINLY DURING WEDNESDAY
MORNING. THERE ARE SOME HINTS THAT FAR NW ZONES COULD END UP GETTING
SOME DEFORMATION AXIS PRECIPITATION WEDNESDAY AFTERNOON...BUT TOO
MUCH UNCERTAINTY TO REFLECT THIS IN FORECAST AT THIS TIME. COULD SEE
SOME GUSTY SW-W WINDS BEHIND THE COLD FRONT.
IMPROVING CONDITIONS WEDNESDAY NIGHT AS CLOSED LOW OPENS UP AND
PILLS TO THE NE...WITH WEAK RIDGING BEGINNING TO BUILD IN LATE.
SPLIT FLOW OVER THE EASTERN U.S. THURSDAY/THURSDAY NIGHT...WITH A
SOUTHERN STREAM TROUGH PASSING TO THE S...AND WEAK RIDGING OVER US
EVOLVING INTO SW FLOW ALOFT.
500 HPA TROUGH APPROACHES FRIDAY THEN CROSSES REGION FRIDAY NIGHT.
WITH LIMITED LOW LEVEL MOISTURE TO WORK WITH...GOING WITH A DRY
PASSAGE FOR NOW.
STRONG RIDGE RE-ESTABLISHES ITSELF OVER FLORIDA...WITH ITS RIDGE
AXIS PUSHING UP INTO THE NE STATES SATURDAY...THEN SLIDING OFFSHORE
SUNDAY. THIS SHOULD KEEP THE REGION DRY.
FOR TEMPERATURES...
FOR HIGHS TUESDAY...BLENDED MAV/MET GUIDANCE. HAVE SUSPICIONS THAT
THIS COULD ULTIMATELY END UP BEING ON THE WARM SIDE...WITH
TEMPERATURES STRUGGLING TO GET OUT OF THE 50S WITH THE TRI-STATE
BEING STUCK UNDER LOW CLOUDS/OCCASIONAL DRIZZLE DUE TO ONSHORE
FLOW...BUT STILL NEED TO SEE A FEW MORE THINGS WORK THEMSELVES OUT
BEFORE GOING THIS ROUTE.
FOR LOWS TUESDAY NIGHT...CONTINUED WITH MAV/MET BLEND...WEIGHING
TOWARDS WARMER GUIDANCE AS MAV TRIES TO COOL THINGS OFF TO MUCH AS
IT ENDS PRECIP TOO SOON.
FOR HIGHS WEDNESDAY USED A MEX/MEX ENSEMBLE MEAN BLEND...THEN
CONTINUED TO USE THIS...WITH HPC GUIDANCE BLENDED IN
THURSDAY-SUNDAY. MAIN PLACE HPC GUIDANCE CHANGED THINGS WAS NEXT
WEEKEND WHERE GFS SOLUTION IS NOTABLY COOLER THAN CURRENTLY
PREFERRED ECMWF SOLUTION.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE REMAINS EAST OF THE TERMINALS THROUGH MONDAY THEN
SLIDES EAST AS LOW PRESSURE APPROACHES FROM THE SOUTH.
RADAR WINDS INDICATING WINDS AT 1K FT AROUND 35 KT FROM THE
SOUTHWEST AND LOW LEVEL WINDS OF 35 TO 40 KT REMAIN THROUGH THE
OVERNIGHT AND INTO THE EARLY MORNING...WILL CONTINUE WITH THE LOW
LEVEL WIND SHEAR. WINDS WILL BECOME MORE SOUTHERLY IN THE AFTERNOON
AND THEN SOUTHEASTERLY MONDAY NIGHT.
LOWERING CONFIDENCE IN STRATUS DEVELOPING OVERNIGHT BUT NOT
COMPLETELY UNLIKELY SO WILL INDICATE MVFR CEILINGS POSSIBLE IN A
TEMPO GROUP. FOG ALSO LESS LIKELY AND REMOVED VISIBILITY
RESTRICTIONS.
FLOW BECOMES MORE SOUTHEASTERLY MONDAY NIGHT AND LOW LEVEL MOISTURE
INCREASES. BY LATE EVENING MVFR TO IFR CONDITIONS WILL BECOME LIKELY
ESPECIALLY ALONG THE COAST. STILL A LOT OF UNCERTAINTY IF THE FOG
AND STRATUS WILL DEVELOP MONDAY NIGHT AND HAVE LOW CONFIDENCE.
OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...
MONDAY NIGHT...FOG AND STRATUS...MVFR TO IFR CONDITIONS.
TUESDAY-WEDNESDAY...PERIODS OF SUB-VFR CONDITIONS POSSIBLE IN
SHOWERS/FOG.
THURSDAY-FRIDAY...VFR.
&&
.MARINE...
DEVELOPING SOUTHERLY FLOW BRINGS POTENTIAL FOR LOW CLOUDS OR FOG
LATE TONIGHT INTO MONDAY MORNING. IF IT ENDS UP BEING FOG...COULD
END UP NEEDING DENSE FOG ADVISORIES...ESPECIALLY NEAR THE COAST.
SOUTHWESTERLY WINDS WILL PERSIST THROUGH TONIGHT INTO TOMORROW
BEFORE SHIFTING TO A SOUTHEASTERLY FLOW BY TUES MORNING. PRESSURE
GRADIENT IS EXPECTED TO RELAX A BIT TONIGHT...AS HIGH DRIFTS
FURTHER OFFSHORE AND A FRONTAL BOUNDARY REMAINS OVER THE SAINT
LAWRENCE RIVER VALLEY. THIS WILL ALLOW FOR WINDS TO GRADUALLY
DIMINISH OVERNIGHT. WAVEWATCH GUIDANCE BROUGHT 5 FT WAVES TO THE
EDGE OF THE MARINE ZONES...WHILE PRODUCING MAINLY 4 FT OVER THE
REST OF THE OCEAN WATER ZONES. HAVE OPTIONED TO NOT ISSUE A SCA
FOR WAVES FOR TONIGHT. AS THE WINDS CONTINUE TO WEAKEN
MONDAY...EXPECT THE SEAS TO SUBSIDE FOR THE DAY BEFORE INCREASING
AGAIN LATE MON NIGHT AS THE WINDS INCREASE WITH THE APPROACHING
LOW FROM THE SOUTH.
STRENGTHENING EASTERLY FLOW SHOULD BUILD AT LEAST SEAS TO SCA LEVELS
ON THE COASTAL OCEAN WATERS TUESDAY AFTERNOON...AND COULD QUITE
POSSIBLY RESULT IN GUSTS TO 25 KT ON ALL WATERS BY THEN AS WELL.
GUSTY WINDS CONTINUE TUESDAY NIGHT...THOUGH FEEL MARINE LAYER WILL
PREVENT BULK OF 45-55KT 950 HPA JET FROM MIXING DOWN...SO KEPT GUSTS
TO SCA LEVELS. WIND GUSTS TO SCA LEVELS SHOULD CONTINUE ON ALL
WATERS INTO WEDNESDAY EVENING...BUT SEAS SHOULD REMAIN AT SCA LEVELS
ON THE COASTAL OCEAN ZONES ALL NIGHT.
IT IS POSSIBLE THAT SCA LEVEL SEAS COULD PERSIST ON ANZ-350 ON
THURSDAY...OTHERWISE EXPECT SUB-SCA CONDITIONS ON ALL WATERS INTO
FRIDAY.
&&
.HYDROLOGY...
LIGHT RAIN IS POSSIBLE OVER THE HUDSON RIVER VALLEY TONIGHT...WITH
JUST A TRACE EXPECTED. DRY WEATHER WILL PERSIST THROUGH MONDAY FOR
THE REST OF THE CWA. THERE IS THE POTENTIAL FOR SIGNIFICANT RAINFALL
FROM LATE TUESDAY INTO WEDNESDAY MORNING. FOR NOW FORECASTING
FROM AROUND 1/2 TO 3/4 AN INCH OF RAINFALL WITH LOCALLY HIGHER
AMOUNTS POSSIBLE. THIS MAKES MINOR URBAN/POOR DRAINAGE FLOODING
THE MOST LIKELY SCENARIO...ESPECIALLY IN AREAS RECEIVING LOCALLY
HEAVY RAINFALL DUE TO PASSING ELEVATED CONVECTION.
&&
.CLIMATE...
THE LATEST GUIDANCE INDICATES THAT HIGHS MONDAY WILL NOT REACH
RECORD HIGH TEMPS. HOWEVER...WITH TEMPS STILL FORECASTED IN THE
LOWER 60S...IT MAY STILL BE POSSIBLE FOR ISOLATED LOCATIONS IN AND
AROUND THE NEW YORK CITY METRO AREA TO COME CLOSE. RECORD HIGH
TEMPS WILL ALSO BE APPROACHED ON TUESDAY...WITH HIGHS ONCE AGAIN
BEING FORECASTED IN THE LOWER TO MID 60S.
FOR MONDAY 11/28
EWR 72/1973
BDR 65/2001
NYC *69/1990
LGA 68/1990
JFK 66/2001
ISP 66/1995
* ALSO OCCURRED IN PREVIOUS YEARS
FOR TUESDAY 11/29
EWR 70/1990
BDR 65/1968
NYC 69/1990
LGA 69/1990
JFK 64/1991
ISP 66/1991
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/SEARS
NEAR TERM...MALOIT/MPS
SHORT TERM...SEARS
LONG TERM...MALOIT
AVIATION...MET
MARINE...MALOIT/SEARS
HYDROLOGY...SEARS
CLIMATE...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1139 PM EST SUN NOV 27 2011
.SYNOPSIS...
HIGH PRESSURE REMAINS OFFSHORE TO THE EAST MONDAY WHILE A LOW
PRESSURE SYSTEM TRACKS EAST ACROSS CANADA...DRAGGING A COLD FRONT
THROUGH NEW ENGLAND. A STORM SYSTEM WILL SLOWLY TRACK FROM THE UPPER
OHIO RIVER VALLEY TO THE CANADIAN MARITIME PROVINCES BY THURSDAY
MORNING. WEAK HIGH PRESSURE BUILDS IN THURSDAY AND THURSDAY
NIGHT...FOLLOWED BY A WEAK COLD FRONT ON FRIDAY. HIGH PRESSURE
THEN BUILDS IN FOR THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
0440Z UPDATE...FORECAST ON TRACK...SO ONLY MINOR CHANGES TO NEXT
COUPLE OF HOURS MADE TO THE DATABASE. WITH WEAK WARM ADVECTION AND
INCREASING CLOUDS...LOWS TONIGHT WILL GENERALLY BOTTOM OUT IN THE
LOW TO MID 50S...AND POSSIBLY INTO THE LOWER 40S ACROSS FAR NW
ZONES.
OTHERWISE...WATER VAPOR SHOWS A DEEP LAYERED RIDGE...WITH THE
RIDGE AXIS TO OUR SW...AND GUIDANCE SUGGESTS THE STATUS QUO WILL
MAINTAIN ITSELF THROUGH TONIGHT. THE RESULT IS MINIMAL IF ANY
FORCING...SO HAVE REMOVED ALL PRECIPITATION FROM TONIGHT. UPDATED
POPS ARE CONSISTENT WITH A BLEND OF HRRR HOURLY AND SREF AND NAM
3-HOUR POPS - WEIGHED MORE TOWARDS THE HRRR IN THE FIRST SIX HOURS
OR SO.
STILL APPEAR ON TRACK FOR FOG OR MORE LIKELY STRATUS TO DEVELOP
OVERNIGHT. QUESTION IS WILL THE FOG BECOME DENSE OR...WILL
ULTIMATELY LOW LEVEL STRATUS WIN OUT. FOR NOW BEGINNING TO LEAN
MORE TOWARDS THE STRATUS BASED ON BUFKIT PROFILES...BUT NOT
CONFIDENT ENOUGH TO REMOVE FOG FROM ZONES AT THIS TIME. HOWEVER IF
THE FOG WINDS OUT...WILL LIKELY SEE DENSE FOG...EVEN MORE
WIDESPREAD THEN LAST NIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
THE LIGHT RAIN/DRIZZLE OVER FAR NW ZONES WILL REMAIN POSSIBLE
THROUGH AROUND 16Z BEFORE THINGS DRY UP FOR THE REST OF THE
PERIOD. HIGH PRESSURE REMAINS TO THE EAST...WITH TWO LOW PRESSURE
SYSTEMS BECOMING THE NEXT FOCUS. THE ONE LOW MOVING THROUGH CANADA
WILL DRAG A COLD FRONT THROUGH NORTHERN NEW ENGLAND. CURRENT
GUIDANCE INDICATES THE FRONT WILL REMAIN NORTH OF THE AREA...AND
THUS SHOULDN/T AFFECT THE CWA. THE SECOND LOW FORMS OVER THE
SOUTHEASTERN US MONDAY MORNING AND PUSHES NORTH THROUGH THE
DAY...SETTLING OVER TN AND KY FOR MON NIGHT. THE UPPER LEVEL RIDGE
WILL BEGIN WEAKENING AS WELL MONDAY...AHEAD OF A DEVELOPING UPPER
LEVEL LOW OVER THE MIDWEST.
SOUTHWESTERLY FLOW WILL PERSIST THROUGH MONDAY...WITH THE WINDS
SHIFTING BACK TO A SOUTHERLY FLOW FOR MON NIGHT. SIDED MORE WITH
A GFS/MOS MIX FOR GUIDANCE FOR WINDS DURING THIS PERIOD AS THE NAM
BRINGS THE WINDS AROUND TO THE EAST MUCH QUICKER...BY 12Z TUES
MORNING. CURRENT THINKING WILL BE THE LOW IS SLIGHTLY SLOWER...AND
THE WINDS WILL BE MORE SOUTHEASTERLY BY 12Z TUES MORNING. THE NAM
ALSO WANTS TO HAVE THE HIGH PRESSURE MORE DOMINANT MON NIGHT...SO
SIDED WITH THE WEAKER HIGH WITH THE GFS. WITH THE GFS
TIMING...BROUGHT IN A SLIGHT CHANCE FOR POPS LATE IN THE PERIOD MON
NIGHT FOR THE FAR WESTERN PORTION OF THE CWA. WITH THE LOWER LEVEL
MOISTURE REMAINING ELEVATED...HAVE ALSO INCLUDED PATCHY FOG AROUND
THE CWA FOR MON NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
GFS IN GENERAL TOO PROGRESSIVE AS HAS BEEN ITS BIAS OF LATE...SO
USED A NAM/ECMWF/SREF BLEND TUESDAY-WEDNESDAY...THEN FOLLOWED THE
ECMWF WEDNESDAY NIGHT-SUNDAY.
UPPER RIDGE AXIS OVER THE REGION SUPPORTS DAMMING HIGH SIGNATURE
OVER THE REGION TUESDAY INTO TUESDAY NIGHT. THIS WILL HELP TO SERVE
TO IMPEDE PROGRESS OF PRECIPITATION INTO THE REGION AHEAD OF CUTOFF
SYSTEM MOVING INTO THE WEST-CENTRAL APPALACHIANS BY TUESDAY EVENING.
AS A RESULT ONLY BRING POPS UP TO LIKELY OVER WESTERN 1/5 OF CWA AND
JUST BARELY TO CHANCE OVER FAR EASTERN PARTS OF THE CWA BY LATE
AFTERNOON.
STRONG ISENTROPIC LIFT DEVELOPS TUESDAY NIGHT...ALONG WITH 50-60 KT
LOW LEVEL JET IMPACTING REGION...ALLOWING FOR MODERATE TO POSSIBLY
LOCALLY HEAVY RAINFALL TO DEVELOP ACROSS THE TRI-STATE TUESDAY
NIGHT. WITH SHOWALTERS 0 TO -2...HAVE ADDED SLIGHT CHANCE OF THUNDER
TO ALL AREAS EAST OF THE HUDSON PLUS MOST OF NE NJ. CATEGORICAL POPS
THROUGHOUT TUESDAY NIGHT (DEVELOP FROM W TO E).
SHOWERS SHOULD TAPER OFF FROM W TO E MAINLY DURING WEDNESDAY
MORNING. THERE ARE SOME HINTS THAT FAR NW ZONES COULD END UP GETTING
SOME DEFORMATION AXIS PRECIPITATION WEDNESDAY AFTERNOON...BUT TOO
MUCH UNCERTAINTY TO REFLECT THIS IN FORECAST AT THIS TIME. COULD SEE
SOME GUSTY SW-W WINDS BEHIND THE COLD FRONT.
IMPROVING CONDITIONS WEDNESDAY NIGHT AS CLOSED LOW OPENS UP AND
PILLS TO THE NE...WITH WEAK RIDGING BEGINNING TO BUILD IN LATE.
SPLIT FLOW OVER THE EASTERN U.S. THURSDAY/THURSDAY NIGHT...WITH A
SOUTHERN STREAM TROUGH PASSING TO THE S...AND WEAK RIDGING OVER US
EVOLVING INTO SW FLOW ALOFT.
500 HPA TROUGH APPROACHES FRIDAY THEN CROSSES REGION FRIDAY NIGHT.
WITH LIMITED LOW LEVEL MOISTURE TO WORK WITH...GOING WITH A DRY
PASSAGE FOR NOW.
STRONG RIDGE RE-ESTABLISHES ITSELF OVER FLORIDA...WITH ITS RIDGE
AXIS PUSHING UP INTO THE NE STATES SATURDAY...THEN SLIDING OFFSHORE
SUNDAY. THIS SHOULD KEEP THE REGION DRY.
FOR TEMPERATURES...
FOR HIGHS TUESDAY...BLENDED MAV/MET GUIDANCE. HAVE SUSPICIONS THAT
THIS COULD ULTIMATELY END UP BEING ON THE WARM SIDE...WITH
TEMPERATURES STRUGGLING TO GET OUT OF THE 50S WITH THE TRI-STATE
BEING STUCK UNDER LOW CLOUDS/OCCASIONAL DRIZZLE DUE TO ONSHORE
FLOW...BUT STILL NEED TO SEE A FEW MORE THINGS WORK THEMSELVES OUT
BEFORE GOING THIS ROUTE.
FOR LOWS TUESDAY NIGHT...CONTINUED WITH MAV/MET BLEND...WEIGHING
TOWARDS WARMER GUIDANCE AS MAV TRIES TO COOL THINGS OFF TO MUCH AS
IT ENDS PRECIP TOO SOON.
FOR HIGHS WEDNESDAY USED A MEX/MEX ENSEMBLE MEAN BLEND...THEN
CONTINUED TO USE THIS...WITH HPC GUIDANCE BLENDED IN
THURSDAY-SUNDAY. MAIN PLACE HPC GUIDANCE CHANGED THINGS WAS NEXT
WEEKEND WHERE GFS SOLUTION IS NOTABLY COOLER THAN CURRENTLY
PREFERRED ECMWF SOLUTION.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE REMAINS EAST OF THE TERMINALS WITH A DEEP SOUTHERLY
FLOW. CONDITIONS START OFF AT VFR...HOWEVER STRATUS IS LIKELY TO
DEVELOP LATE THIS EVENING INTO THE OVERNIGHT TOWARD 07Z...WITH
MVFR CEILINGS. DO NOT HAVE HIGH CONFIDENCE IN IFR CEILINGS
DEVELOPING...AND MODERATE IF ANY STRATUS DEVELOPS. WITH THE UPDATE
REMOVED IFR CEILINGS FROM THE TERMINALS. IF VISIBILITIES LOWER
WILL BE BRIEFLY TO MVFR. CONFIDENCE FOR FOG DEVELOPMENT LOWER
THAN FOR STRATUS.
IMPROVEMENT BACK TO VFR WILL OCCUR AROUND MID MORNING...13Z TO 15Z.
OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
MONDAY NIGHT...FOG AND STRATUS DEVELOPING WITH MVFR TO IFR
CONDITIONS.
TUESDAY-WEDNESDAY...PERIODS OF SUB-VFR CONDITIONS POSSIBLE IN
SHOWERS/FOG.
THURSDAY-FRIDAY...VFR.
&&
.MARINE...
DEVELOPING SOUTHERLY FLOW BRINGS POTENTIAL FOR LOW CLOUDS OR FOG
LATE TONIGHT INTO MONDAY MORNING. IF IT ENDS UP BEING FOG...COULD
END UP NEEDING DENSE FOG ADVISORIES...ESPECIALLY NEAR THE COAST.
SOUTHWESTERLY WINDS WILL PERSIST THROUGH TONIGHT INTO TOMORROW
BEFORE SHIFTING TO A SOUTHEASTERLY FLOW BY TUES MORNING. PRESSURE
GRADIENT IS EXPECTED TO RELAX A BIT TONIGHT...AS HIGH DRIFTS
FURTHER OFFSHORE AND A FRONTAL BOUNDARY REMAINS OVER THE SAINT
LAWRENCE RIVER VALLEY. THIS WILL ALLOW FOR WINDS TO GRADUALLY
DIMINISH OVERNIGHT. WAVEWATCH GUIDANCE BROUGHT 5 FT WAVES TO THE
EDGE OF THE MARINE ZONES...WHILE PRODUCING MAINLY 4 FT OVER THE
REST OF THE OCEAN WATER ZONES. HAVE OPTIONED TO NOT ISSUE A SCA
FOR WAVES FOR TONIGHT. AS THE WINDS CONTINUE TO WEAKEN
MONDAY...EXPECT THE SEAS TO SUBSIDE FOR THE DAY BEFORE INCREASING
AGAIN LATE MON NIGHT AS THE WINDS INCREASE WITH THE APPROACHING
LOW FROM THE SOUTH.
STRENGTHENING EASTERLY FLOW SHOULD BUILD AT LEAST SEAS TO SCA LEVELS
ON THE COASTAL OCEAN WATERS TUESDAY AFTERNOON...AND COULD QUITE
POSSIBLY RESULT IN GUSTS TO 25 KT ON ALL WATERS BY THEN AS WELL.
GUSTY WINDS CONTINUE TUESDAY NIGHT...THOUGH FEEL MARINE LAYER WILL
PREVENT BULK OF 45-55KT 950 HPA JET FROM MIXING DOWN...SO KEPT GUSTS
TO SCA LEVELS. WIND GUSTS TO SCA LEVELS SHOULD CONTINUE ON ALL
WATERS INTO WEDNESDAY EVENING...BUT SEAS SHOULD REMAIN AT SCA LEVELS
ON THE COASTAL OCEAN ZONES ALL NIGHT.
IT IS POSSIBLE THAT SCA LEVEL SEAS COULD PERSIST ON ANZ-350 ON
THURSDAY...OTHERWISE EXPECT SUB-SCA CONDITIONS ON ALL WATERS INTO
FRIDAY.
&&
.HYDROLOGY...
LIGHT RAIN IS POSSIBLE OVER THE HUDSON RIVER VALLEY TONIGHT...WITH
JUST A TRACE EXPECTED. DRY WEATHER WILL PERSIST THROUGH MONDAY FOR
THE REST OF THE CWA. THERE IS THE POTENTIAL FOR SIGNIFICANT RAINFALL
FROM LATE TUESDAY INTO WEDNESDAY MORNING. FOR NOW FORECASTING
FROM AROUND 1/2 TO 3/4 AN INCH OF RAINFALL WITH LOCALLY HIGHER
AMOUNTS POSSIBLE. THIS MAKES MINOR URBAN/POOR DRAINAGE FLOODING
THE MOST LIKELY SCENARIO...ESPECIALLY IN AREAS RECEIVING LOCALLY
HEAVY RAINFALL DUE TO PASSING ELEVATED CONVECTION.
&&
.CLIMATE...
THE LATEST GUIDANCE INDICATES THAT HIGHS MONDAY WILL NOT REACH
RECORD HIGH TEMPS. HOWEVER...WITH TEMPS STILL FORECASTED IN THE
LOWER 60S...IT MAY STILL BE POSSIBLE FOR ISOLATED LOCATIONS IN AND
AROUND THE NEW YORK CITY METRO AREA TO COME CLOSE. RECORD HIGH
TEMPS WILL ALSO BE APPROACHED ON TUESDAY...WITH HIGHS ONCE AGAIN
BEING FORECASTED IN THE LOWER TO MID 60S.
FOR MONDAY 11/28
EWR 72/1973
BDR 65/2001
NYC *69/1990
LGA 68/1990
JFK 66/2001
ISP 66/1995
* ALSO OCCURRED IN PREVIOUS YEARS
FOR TUESDAY 11/29
EWR 70/1990
BDR 65/1968
NYC 69/1990
LGA 69/1990
JFK 64/1991
ISP 66/1991
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/SEARS
NEAR TERM...MALOIT/MPS
SHORT TERM...SEARS
LONG TERM...MALOIT
AVIATION...MET
MARINE...MALOIT/SEARS
HYDROLOGY...SEARS
CLIMATE...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1001 PM CST TUE NOV 29 2011
.DISCUSSION...
840 PM CST
HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST THIS EVENING TO TWEAK
FOR CURRENT TRENDS. WINDS CONTINUE TO DIMINISH ACROSS ILLINOIS AS
THE TIGHTER PRESSURE GRADIENT SHIFTS TO THE EAST AS THE LOW MOVES
OVER LAKE ERIE. WIND DIRECTION HAS SHIFTED SLIGHTLY WEST OF NORTH
WHICH HAS ALLOWED MORE OF AN OFFSHORE WIND TO SET UP ALONG THE
ILLINOIS SHORE RESULTING IN WINDS FALLING BELOW ADVISORY CRITERIA.
WINDS OVER THE WATER REMAIN STRONG WITH GUSTS INTO THE 35-45 KT
RANGE WHICH CONTINUE TO MOVE ONSHORE ACROSS NORTHWEST INDIANA.
SOME GUSTS TO 35-40 KT MAY ALSO BE AFFECTING THE FAR SOUTHERN COOK
COUNTY LAKESHORE BUT THIS SHOULD BE INFREQUENT. FORECAST SOUNDINGS
SHOW THAT WINDS OFF THE DECK WILL QUICKLY DIMINISH ACROSS NW
INDIANA TO THE POINT WHERE ADVISORY LEVEL SPEEDS WOULD NOT BE
SUPPORTED TOWARDS 06-07Z. GIVEN THIS AND THE STRONGER WINDS
CONTINUING ACROSS LAKE AND PORTER COUNTY INDIANA AT THIS HOUR HAVE
EXTENDED THE WIND ADVISORY UNTIL 07Z. OTHERWISE SKIES CONTINUE TO
CLEAR FROM THE WEST ALLOWING TEMPS JUST WEST OF THE CWA TO FALL
INTO THE UPPER 20S WITH SIMILAR READINGS NOT FAR BEHIND FOR THE
WESTERN CWA. GOING FORECAST LOWS STILL LOOK ON TRACK.
MDB
//PREV DISCUSSION...
313 PM CST
MESOSCALE/TONIGHT...
A VERY IMPRESSIVE WATER VAPOR SATELLITE LOOP THIS AFTERNOON
REVEALS THE EXPANSIVE COLD CORE LOW LIFTING NORTHEAST ACROSS THE
APPALACHIANS...JUST GRAZING THE AREA. A WELL-DEFINED DEFORMATION
AREA HAS FILLED IN WITH BANDS OF COLDER AND AT TIMES CONVECTIVE
CLOUD TOPS PROVIDING HEAVIER AND FROZEN PRECIPITATION ACROSS PARTS
OF NORTHERN IN. THE DUAL POLARIZATION RADAR EVEN DETECTED THE
PRECIPITATION TYPE SWITCH AT 7000-9000 FT. THIS HAS BEEN OBSERVED
AT THE GROUND JUST TO THE SOUTH AND EAST OF THE FORECAST AREA IN
LAFAYETTE /WHERE SLUSHY ACCUMULATION HAS OCCURRED ON GRASSY
SURFACES/. THE 13KM RUC SOUNDINGS ACROSS BENTON AND JASPER
COUNTIES CONTINUE TO SHOW A GRADUAL SHRINKING OF THE NEAR-SURFACE
WARM LAYER TO ALLOW FOR A MIX TO MAKE IT TO THE GROUND FOR
POSSIBLY A COUPLE HOURS. THAT COUPLE OF HOURS LOOKS TO BE IT GIVEN
SATELLITE AND SHORT TERM MODEL TRENDS TO SHIFT THE FORCING EAST.
GIVEN THAT ANY TRANSITION WILL BE SO SHORT LIVED AND OVER WARM
GROUND...WILL CANCEL THE WINTER WEATHER ADVISORY.
STRONG NORTHERLY WINDS HAVING GUSTED AS HIGH AS 60 MPH AT THE
CHICAGO CRIB...52 MPH AT GARY...AND 48 MPH AT MIDWAY WILL
GRADUALLY DIMINISH THROUGH THE EVENING WITH THE AREA PINCHED
BETWEEN THE 1001 MB LOW NEAR CLEVELAND AND THE INCOMING 1027 MB
RIDGE. AN AIRCRAFT SOUNDING OUT OF OHARE JUST AFTER 2 PM REVEALED
40 KT WINDS AT THE TOP OF THE CHANNEL...AND NAM AND RUC SOUNDINGS
KEEP SIMILAR SPEEDS WITHIN THE BOUNDARY LAYER UNTIL A COUPLE HOURS
AFTER SUNSET. WITH STILL AN ONSHORE COMPONENT TO THE WIND...WILL
LET THE WIND ADVISORY CONTINUE. A QUICK DECOUPLING LATER IN THE
EVENING SHOULD ALLOW FOR WINDS TO COME DOWN MORE RAPIDLY ACROSS
THE ILLINOIS FORECAST AREA. ASSOCIATED LAKE SHORE FLOODING
CONCERNS WITH THE WIND ALSO CONTINUE GIVEN THE 10 TO 15 FT WAVES
FORECAST...BUT LIKELY WILL NOT LAST AS FAR INTO WEDNESDAY. CLOUDS
SHOULD SCOUR FAIRLY QUICKLY WEST OF CHICAGO THROUGH EARLY
EVENING...THEN MORE SLOWLY DOWNSTREAM OF THE LAKE. WHILE SOME LAKE
ENHANCED CLOUDS MAY OCCUR...FORECAST DEPTHS ARE VERY SHALLOW WITH
DRIER AIR BEING RAKED IN ON THE NORTHERLY WINDS...AND THUS NOT
EXPECTING ANY SHOWERS. WITH FORECAST TEMPERATURES HAVE MADE ONLY
MINOR TWEAKS...WITH READINGS ALMOST RIGHT AT NORMAL ACROSS THE
ENTIRE FORECAST AREA.
MTF
WEDNESDAY THROUGH TUESDAY...
ACTUALLY LOOKING LIKE A DAY OR TWO OF FAIRLY PLEASANT LATE NOVEMBER
WEATHER WEDNESDAY INTO THURSDAY IN WAKE OF TODAY`S SIDESWIPING BY
THE STRONG STORM SYSTEM. WARM AIR ADVECTION WILL COMMENCE WEDNESDAY
AS LOW/MID LEVEL FLOW BEGINS TO BACK IN ADVANCE OF THE NEXT NORTHERN
STREAM SHORTWAVE WHICH WILL BEGIN DROPPING INTO THE NORTHERN PLAINS.
AFTER A CHILLY MORNING TEMPS SHOULD REBOUND NICELY TOMORROW WITH
NEARLY FULL SUNSHINE.
INCREASING MID/HIGH LEVEL CLOUDINESS AND SOUTHWEST WINDS SHOULD KEEP
TEMPS A BIT WARMER TOMORROW NIGHT WHICH WILL THEN PROVIDE FOR A NICE
SPRING BOARD FOR TEMPS THURSDAY TO CLIMB BACK TO SEVERAL DEGREES
ABOVE AVERAGE. COLD FRONT WILL THEN DROP SOUTHWARD ACROSS THE CWA
LATE THURSDAY AFTERNOON/EARLY THURSDAY EVENING. STRONGEST FORCING
WITH THIS WAVE LOOKS TO PASS WELL NORTH/NORTHEAST OF THE AREA AND
WITH SCANT MOISTURE AT BEST AM HAVING A HARD TIME GETTING TOO WORKED
UP OVER OUR SNOW CHANCES THURSDAY NIGHT. ECMWF/GFS BOTH STILL TRYING
TO SPIT OUT A HUNDREDTH OF AN INCH OR SO OF QPF SO HAVE MAINTAINED
THE SLIGHT CHANCE POPS WE HAD GOING...WHICH ARE SUPPORTED BY CURRENT
MOS NUMBERS.
VERY QUICK HITTING SHOT OF FAIRLY COLD AIR THEN ARRIVES LATER
THURSDAY NIGHT AND ESPECIALLY FRIDAY. THERE STILL DOES APPEAR TO BE
A SMALL WINDOW OF OPPORTUNITY FOR SOME LAKE EFFECT SNOW SHOWERS IN
PORTER COUNTY LATE THURSDAY NIGHT INTO FRIDAY MORNING...BUT NOT
EXPECTING ANYTHING SIGNIFICANT WITH LAKE EFFECT PARAMETERS FAIRLY
MARGINAL AND DURATION BEING SHORT AS FLOW QUICKLY BACKS TO
SOUTHERLY FRIDAY AFTERNOON.
BY THIS WEEKEND OUR ATTENTION WILL TURN THE THE VIGOROUS UPPER LOW
THATS CURRENTLY OFF THE BRITISH COLUMBIA COAST. MEDIUM RANGE
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT THROUGH FRIDAY WITH THIS
SYSTEM DROPPING SOUTH AND WITH AN ANOMALOUSLY STRONG UPPER LOW (H5
HEIGHTS 3+ STANDARD DEVIATIONS BELOW AVERAGE) SETTING UP SHOP OVER
THE DESSERT SOUTHWEST BY FRIDAY. MODERATE RIDGING DOWNSTREAM OVER
THE SOUTHEASTERN CONUS SHOULD LEAVE OUR AREA IN A WEST-SOUTHWEST
FLOW ALOFT.
FORECAST CONFIDENCE THIS WEEKEND INTO EARLY NEXT WEEK IS LOW AS
MODELS OFTEN STRUGGLE WITH CUT OFF LOWS. HAVING SAID THAT...IT
APPEARS AS THOUGH THIS FIRST UPPER LOW WILL WEAKEN INTO AN OPEN WAVE
AND RIDE THE SOUTHWEST FLOW ALOFT INTO OUR AREA THIS WEEKEND...WITH
SOME DEGREE OF PHASING WITH A RESULTANT AMPLIFYING NORTHERN
STREAM TROUGH EXPECTED. WHILE DETAILS ARE MURKY...IT WOULD APPEAR
THAT OUR AREA IS IN STORE FOR INCREASINGLY UNSETTLED WEATHER LATE
SATURDAY INTO SUNDAY. WITH VARYING SOLUTIONS ABOUT THE TRACK OF
THE SURFACE SYSTEM AND RESULTANT THERMAL PROFILES IT WOULD BE
ABSURD TRYING TO PINPOINT P-TYPES FOR THE WEEKEND JUST YET.
ANOTHER...POTENTIALLY MORE SIGNIFICANT BUT BRIEF BLAST OF COLD AIR
LOOKS TO ARRIVE IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 04Z...
* NORTH TO NORTHWEST WINDS GRADUALLY DIMINISHING THIS EVENING
* NO OTHER CONCERNS OVERNIGHT
SHEA
//DISCUSSION...UPDATED 00Z...
WINDS CONTINUE TO TAPER OFF THIS EVENING AS A STRONG LOW PRESSURE
SYSTEM MOVES OUT OF THE REGION. SURFACE PRESSURE GRADIENT REMAINS
TIGHT THIS EVENING BUT WILL CONTINUE TO RELAX THROUGHOUT THE
NIGHT...WITH WINDS EVENTUALLY DIPPING BELOW 20 KT LATER TONIGHT.
CIGS WILL CONTINUE TO DECREASE THROUGH THE EVENING AND A FEW LOW
END VFR CIGS MAY PERSIST INTO THE EARLY EVENING HOURS. SURFACE
HIGH PRESSURE WILL CONTINUE TO SWING INTO THE REGION...WITH THE
DRYING TREND CONTINUING WITH GENERALLY CLEAR SKIES AND LIGHT WINDS
ANTICIPATED BY TOMORROW AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 04Z...
* MOD-HIGH CONFIDENCE IN WIND FORECAST
* HIGH CONFIDENCE IN CIG FORECAST
SHEA
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY...VFR. CHC LGT SN WITH MVFR IN THE EVENING.
* FRIDAY...CHC SHSN IN THE MORNING.
* SATURDAY...SLT CHC OF RA/SN WITH MVFR POSSIBLE.
* SUNDAY...CHC RA/SN. MVFR POSSIBLE.
* MONDAY...VFR.
SHEA
&&
.MARINE...
153 PM...LOW PRESSURE NEAR LAKE ERIE WILL CONTINUE TO LIFT
NORTHEAST TONIGHT AND INTO QUEBEC WEDNESDAY MORNING WHILE A LARGE
RIDGE OF HIGH PRESSURE EXTENDS FROM JAMES BAY SOUTHWEST INTO THE
CENTRAL PLAINS. THE GRADIENT BETWEEN THESE TWO FEATURES WILL
REMAIN STRONG BUT SLOWLY WEAKEN TONIGHT. SPEEDS/GUSTS PEAKED MID
MORNING AND EXPECT GALES IN THE 40-45 KT RANGE FOR MUCH OF THE
EVENING...BUT THREAT FOR STORM FORCE GUSTS TO 50 KT APPEARS TO
HAVE ENDED.
THE RIDGE NOTED ABOVE WILL SPLIT TONIGHT AS ONE AREA MOVES EAST
ACROSS NORTHERN QUEBEC AND THE SOUTHERN AREA DROPS SOUTH ACROSS THE
SOUTHERN PLAINS AND OHIO VALLEY WEDNESDAY. THE NORTHERN PORTION OF
THIS RIDGE WILL MOVE ACROSS LAKE MICHIGAN WEDNESDAY AFTERNOON WITH
WIND SPEEDS RAPIDLY DIMINISHING WEDNESDAY MORNING AND BECOMING
SOUTHWEST BY EVENING.
A WEAK LOW WILL DEVELOP OVER THE PLAINS WEDNESDAY NIGHT AND QUICKLY
MOVE ACROSS THE NORTHERN LAKES REGION THURSDAY AFTERNOON...
DRAGGING A COLD FRONT ACROSS THE LAKE THURSDAY NIGHT. THE GRADIENT
TIGHTENS BEHIND THIS FRONT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE PLAINS. BUT IN ADDITION TO THE TIGHTENING GRADIENT...COLDER
AIR WILL ALSO BE SPREADING ACROSS THE REGION AND EXPECT NORTHERLY
WINDS GUSTING TO AT LEAST 30 KTS WITH THE POTENTIAL FOR SOME GUSTS
TO 35 KTS. THIS HIGH THEN QUICKLY MOVES EAST ON FRIDAY WITH
SOUTHERLY WINDS DEVELOPING OVER THE LAKE FRIDAY NIGHT AS LOW
PRESSURE LIFTS NORTH ACROSS CANADA. ANOTHER COLD FRONT THEN MOVES
ACROSS THE LAKES REGION SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM WEDNESDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 3 PM WEDNESDAY.
WIND ADVISORY...INZ001-INZ002 UNTIL 1 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
845 PM CST TUE NOV 29 2011
.DISCUSSION...
840 PM CST
HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST THIS EVENING TO TWEAK
FOR CURRENT TRENDS. WINDS CONTINUE TO DIMINISH ACROSS ILLINOIS AS
THE TIGHTER PRESSURE GRADIENT SHIFTS TO THE EAST AS THE LOW MOVES
OVER LAKE ERIE. WIND DIRECTION HAS SHIFTED SLIGHTLY WEST OF NORTH
WHICH HAS ALLOWED MORE OF AN OFFSHORE WIND TO SET UP ALONG THE
ILLINOIS SHORE RESULTING IN WINDS FALLING BELOW ADVISORY CRITERIA.
WINDS OVER THE WATER REMAIN STRONG WITH GUSTS INTO THE 35-45 KT
RANGE WHICH CONTINUE TO MOVE ONSHORE ACROSS NORTHWEST INDIANA.
SOME GUSTS TO 35-40 KT MAY ALSO BE AFFECTING THE FAR SOUTHERN COOK
COUNTY LAKESHORE BUT THIS SHOULD BE INFREQUENT. FORECAST SOUNDINGS
SHOW THAT WINDS OFF THE DECK WILL QUICKLY DIMINISH ACROSS NW
INDIANA TO THE POINT WHERE ADVISORY LEVEL SPEEDS WOULD NOT BE
SUPPORTED TOWARDS 06-07Z. GIVEN THIS AND THE STRONGER WINDS
CONTINUING ACROSS LAKE AND PORTER COUNTY INDIANA AT THIS HOUR HAVE
EXTENDED THE WIND ADVISORY UNTIL 07Z. OTHERWISE SKIES CONTINUE TO
CLEAR FROM THE WEST ALLOWING TEMPS JUST WEST OF THE CWA TO FALL
INTO THE UPPER 20S WITH SIMILAR READINGS NOT FAR BEHIND FOR THE
WESTERN CWA. GOING FORECAST LOWS STILL LOOK ON TRACK.
MDB
&&
.PREV DISCUSSION...
313 PM CST
MESOSCALE/TONIGHT...
A VERY IMPRESSIVE WATER VAPOR SATELLITE LOOP THIS AFTERNOON
REVEALS THE EXPANSIVE COLD CORE LOW LIFTING NORTHEAST ACROSS THE
APPALACHIANS...JUST GRAZING THE AREA. A WELL-DEFINED DEFORMATION
AREA HAS FILLED IN WITH BANDS OF COLDER AND AT TIMES CONVECTIVE
CLOUD TOPS PROVIDING HEAVIER AND FROZEN PRECIPITATION ACROSS PARTS
OF NORTHERN IN. THE DUAL POLARIZATION RADAR EVEN DETECTED THE
PRECIPITATION TYPE SWITCH AT 7000-9000 FT. THIS HAS BEEN OBSERVED
AT THE GROUND JUST TO THE SOUTH AND EAST OF THE FORECAST AREA IN
LAFAYETTE /WHERE SLUSHY ACCUMULATION HAS OCCURRED ON GRASSY
SURFACES/. THE 13KM RUC SOUNDINGS ACROSS BENTON AND JASPER
COUNTIES CONTINUE TO SHOW A GRADUAL SHRINKING OF THE NEAR-SURFACE
WARM LAYER TO ALLOW FOR A MIX TO MAKE IT TO THE GROUND FOR
POSSIBLY A COUPLE HOURS. THAT COUPLE OF HOURS LOOKS TO BE IT GIVEN
SATELLITE AND SHORT TERM MODEL TRENDS TO SHIFT THE FORCING EAST.
GIVEN THAT ANY TRANSITION WILL BE SO SHORT LIVED AND OVER WARM
GROUND...WILL CANCEL THE WINTER WEATHER ADVISORY.
STRONG NORTHERLY WINDS HAVING GUSTED AS HIGH AS 60 MPH AT THE
CHICAGO CRIB...52 MPH AT GARY...AND 48 MPH AT MIDWAY WILL
GRADUALLY DIMINISH THROUGH THE EVENING WITH THE AREA PINCHED
BETWEEN THE 1001 MB LOW NEAR CLEVELAND AND THE INCOMING 1027 MB
RIDGE. AN AIRCRAFT SOUNDING OUT OF OHARE JUST AFTER 2 PM REVEALED
40 KT WINDS AT THE TOP OF THE CHANNEL...AND NAM AND RUC SOUNDINGS
KEEP SIMILAR SPEEDS WITHIN THE BOUNDARY LAYER UNTIL A COUPLE HOURS
AFTER SUNSET. WITH STILL AN ONSHORE COMPONENT TO THE WIND...WILL
LET THE WIND ADVISORY CONTINUE. A QUICK DECOUPLING LATER IN THE
EVENING SHOULD ALLOW FOR WINDS TO COME DOWN MORE RAPIDLY ACROSS
THE ILLINOIS FORECAST AREA. ASSOCIATED LAKE SHORE FLOODING
CONCERNS WITH THE WIND ALSO CONTINUE GIVEN THE 10 TO 15 FT WAVES
FORECAST...BUT LIKELY WILL NOT LAST AS FAR INTO WEDNESDAY. CLOUDS
SHOULD SCOUR FAIRLY QUICKLY WEST OF CHICAGO THROUGH EARLY
EVENING...THEN MORE SLOWLY DOWNSTREAM OF THE LAKE. WHILE SOME LAKE
ENHANCED CLOUDS MAY OCCUR...FORECAST DEPTHS ARE VERY SHALLOW WITH
DRIER AIR BEING RAKED IN ON THE NORTHERLY WINDS...AND THUS NOT
EXPECTING ANY SHOWERS. WITH FORECAST TEMPERATURES HAVE MADE ONLY
MINOR TWEAKS...WITH READINGS ALMOST RIGHT AT NORMAL ACROSS THE
ENTIRE FORECAST AREA.
MTF
WEDNESDAY THROUGH TUESDAY...
ACTUALLY LOOKING LIKE A DAY OR TWO OF FAIRLY PLEASANT LATE NOVEMBER
WEATHER WEDNESDAY INTO THURSDAY IN WAKE OF TODAY`S SIDESWIPING BY
THE STRONG STORM SYSTEM. WARM AIR ADVECTION WILL COMMENCE WEDNESDAY
AS LOW/MID LEVEL FLOW BEGINS TO BACK IN ADVANCE OF THE NEXT NORTHERN
STREAM SHORTWAVE WHICH WILL BEGIN DROPPING INTO THE NORTHERN PLAINS.
AFTER A CHILLY MORNING TEMPS SHOULD REBOUND NICELY TOMORROW WITH
NEARLY FULL SUNSHINE.
INCREASING MID/HIGH LEVEL CLOUDINESS AND SOUTHWEST WINDS SHOULD KEEP
TEMPS A BIT WARMER TOMORROW NIGHT WHICH WILL THEN PROVIDE FOR A NICE
SPRING BOARD FOR TEMPS THURSDAY TO CLIMB BACK TO SEVERAL DEGREES
ABOVE AVERAGE. COLD FRONT WILL THEN DROP SOUTHWARD ACROSS THE CWA
LATE THURSDAY AFTERNOON/EARLY THURSDAY EVENING. STRONGEST FORCING
WITH THIS WAVE LOOKS TO PASS WELL NORTH/NORTHEAST OF THE AREA AND
WITH SCANT MOISTURE AT BEST AM HAVING A HARD TIME GETTING TOO WORKED
UP OVER OUR SNOW CHANCES THURSDAY NIGHT. ECMWF/GFS BOTH STILL TRYING
TO SPIT OUT A HUNDREDTH OF AN INCH OR SO OF QPF SO HAVE MAINTAINED
THE SLIGHT CHANCE POPS WE HAD GOING...WHICH ARE SUPPORTED BY CURRENT
MOS NUMBERS.
VERY QUICK HITTING SHOT OF FAIRLY COLD AIR THEN ARRIVES LATER
THURSDAY NIGHT AND ESPECIALLY FRIDAY. THERE STILL DOES APPEAR TO BE
A SMALL WINDOW OF OPPORTUNITY FOR SOME LAKE EFFECT SNOW SHOWERS IN
PORTER COUNTY LATE THURSDAY NIGHT INTO FRIDAY MORNING...BUT NOT
EXPECTING ANYTHING SIGNIFICANT WITH LAKE EFFECT PARAMETERS FAIRLY
MARGINAL AND DURATION BEING SHORT AS FLOW QUICKLY BACKS TO
SOUTHERLY FRIDAY AFTERNOON.
BY THIS WEEKEND OUR ATTENTION WILL TURN THE THE VIGOROUS UPPER LOW
THATS CURRENTLY OFF THE BRITISH COLUMBIA COAST. MEDIUM RANGE
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT THROUGH FRIDAY WITH THIS
SYSTEM DROPPING SOUTH AND WITH AN ANOMALOUSLY STRONG UPPER LOW (H5
HEIGHTS 3+ STANDARD DEVIATIONS BELOW AVERAGE) SETTING UP SHOP OVER
THE DESSERT SOUTHWEST BY FRIDAY. MODERATE RIDGING DOWNSTREAM OVER
THE SOUTHEASTERN CONUS SHOULD LEAVE OUR AREA IN A WEST-SOUTHWEST
FLOW ALOFT.
FORECAST CONFIDENCE THIS WEEKEND INTO EARLY NEXT WEEK IS LOW AS
MODELS OFTEN STRUGGLE WITH CUT OFF LOWS. HAVING SAID THAT...IT
APPEARS AS THOUGH THIS FIRST UPPER LOW WILL WEAKEN INTO AN OPEN WAVE
AND RIDE THE SOUTHWEST FLOW ALOFT INTO OUR AREA THIS WEEKEND...WITH
SOME DEGREE OF PHASING WITH A RESULTANT AMPLIFYING NORTHERN
STREAM TROUGH EXPECTED. WHILE DETAILS ARE MURKY...IT WOULD APPEAR
THAT OUR AREA IS IN STORE FOR INCREASINGLY UNSETTLED WEATHER LATE
SATURDAY INTO SUNDAY. WITH VARYING SOLUTIONS ABOUT THE TRACK OF
THE SURFACE SYSTEM AND RESULTANT THERMAL PROFILES IT WOULD BE
ABSURD TRYING TO PINPOINT P-TYPES FOR THE WEEKEND JUST YET.
ANOTHER...POTENTIALLY MORE SIGNIFICANT BUT BRIEF BLAST OF COLD AIR
LOOKS TO ARRIVE IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 02Z...
* NORTH TO NORTHWEST WINDS GRADUALLY DIMINISHING THIS EVENING
* NO OTHER CONCERNS OVERNIGHT
SHEA
//DISCUSSION...UPDATED 00Z...
WINDS CONTINUE TO TAPER OFF THIS EVENING AS A STRONG LOW PRESSURE
SYSTEM MOVES OUT OF THE REGION. SURFACE PRESSURE GRADIENT REMAINS
TIGHT THIS EVENING BUT WILL CONTINUE TO RELAX THROUGHOUT THE
NIGHT...WITH WINDS EVENTUALLY DIPPING BELOW 20 KT LATER TONIGHT.
CIGS WILL CONTINUE TO DECREASE THROUGH THE EVENING AND A FEW LOW
END VFR CIGS MAY PERSIST INTO THE EARLY EVENING HOURS. SURFACE
HIGH PRESSURE WILL CONTINUE TO SWING INTO THE REGION...WITH THE
DRYING TREND CONTINUING WITH GENERALLY CLEAR SKIES AND LIGHT WINDS
ANTICIPATED BY TOMORROW AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 02Z...
* MOD-HIGH CONFIDENCE IN WIND FORECAST
* HIGH CONFIDENCE IN CIG FORECAST
SHEA
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY...VFR. CHC LGT SN WITH MVFR IN THE EVENING.
* FRIDAY...CHC SHSN IN THE MORNING.
* SATURDAY...SLT CHC OF RA/SN WITH MVFR POSSIBLE.
* SUNDAY...CHC RA/SN. MVFR POSSIBLE.
* MONDAY...VFR.
SHEA
&&
.MARINE...
153 PM...LOW PRESSURE NEAR LAKE ERIE WILL CONTINUE TO LIFT
NORTHEAST TONIGHT AND INTO QUEBEC WEDNESDAY MORNING WHILE A LARGE
RIDGE OF HIGH PRESSURE EXTENDS FROM JAMES BAY SOUTHWEST INTO THE
CENTRAL PLAINS. THE GRADIENT BETWEEN THESE TWO FEATURES WILL
REMAIN STRONG BUT SLOWLY WEAKEN TONIGHT. SPEEDS/GUSTS PEAKED MID
MORNING AND EXPECT GALES IN THE 40-45 KT RANGE FOR MUCH OF THE
EVENING...BUT THREAT FOR STORM FORCE GUSTS TO 50 KT APPEARS TO
HAVE ENDED.
THE RIDGE NOTED ABOVE WILL SPLIT TONIGHT AS ONE AREA MOVES EAST
ACROSS NORTHERN QUEBEC AND THE SOUTHERN AREA DROPS SOUTH ACROSS THE
SOUTHERN PLAINS AND OHIO VALLEY WEDNESDAY. THE NORTHERN PORTION OF
THIS RIDGE WILL MOVE ACROSS LAKE MICHIGAN WEDNESDAY AFTERNOON WITH
WIND SPEEDS RAPIDLY DIMINISHING WEDNESDAY MORNING AND BECOMING
SOUTHWEST BY EVENING.
A WEAK LOW WILL DEVELOP OVER THE PLAINS WEDNESDAY NIGHT AND QUICKLY
MOVE ACROSS THE NORTHERN LAKES REGION THURSDAY AFTERNOON...
DRAGGING A COLD FRONT ACROSS THE LAKE THURSDAY NIGHT. THE GRADIENT
TIGHTENS BEHIND THIS FRONT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE PLAINS. BUT IN ADDITION TO THE TIGHTENING GRADIENT...COLDER
AIR WILL ALSO BE SPREADING ACROSS THE REGION AND EXPECT NORTHERLY
WINDS GUSTING TO AT LEAST 30 KTS WITH THE POTENTIAL FOR SOME GUSTS
TO 35 KTS. THIS HIGH THEN QUICKLY MOVES EAST ON FRIDAY WITH
SOUTHERLY WINDS DEVELOPING OVER THE LAKE FRIDAY NIGHT AS LOW
PRESSURE LIFTS NORTH ACROSS CANADA. ANOTHER COLD FRONT THEN MOVES
ACROSS THE LAKES REGION SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ006-ILZ014 UNTIL 9 PM TUESDAY.
LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM WEDNESDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 3 PM WEDNESDAY.
WIND ADVISORY...INZ001-INZ002 UNTIL 9 PM TUESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
806 PM CST TUE NOV 29 2011
.DISCUSSION...
313 PM CST
MESOSCALE/TONIGHT...
A VERY IMPRESSIVE WATER VAPOR SATELLITE LOOP THIS AFTERNOON
REVEALS THE EXPANSIVE COLD CORE LOW LIFTING NORTHEAST ACROSS THE
APPALACHIANS...JUST GRAZING THE AREA. A WELL-DEFINED DEFORMATION
AREA HAS FILLED IN WITH BANDS OF COLDER AND AT TIMES CONVECTIVE
CLOUD TOPS PROVIDING HEAVIER AND FROZEN PRECIPITATION ACROSS PARTS
OF NORTHERN IN. THE DUAL POLARIZATION RADAR EVEN DETECTED THE
PRECIPITATION TYPE SWITCH AT 7000-9000 FT. THIS HAS BEEN OBSERVED
AT THE GROUND JUST TO THE SOUTH AND EAST OF THE FORECAST AREA IN
LAFAYETTE /WHERE SLUSHY ACCUMULATION HAS OCCURRED ON GRASSY
SURFACES/. THE 13KM RUC SOUNDINGS ACROSS BENTON AND JASPER
COUNTIES CONTINUE TO SHOW A GRADUAL SHRINKING OF THE NEAR-SURFACE
WARM LAYER TO ALLOW FOR A MIX TO MAKE IT TO THE GROUND FOR
POSSIBLY A COUPLE HOURS. THAT COUPLE OF HOURS LOOKS TO BE IT GIVEN
SATELLITE AND SHORT TERM MODEL TRENDS TO SHIFT THE FORCING EAST.
GIVEN THAT ANY TRANSITION WILL BE SO SHORT LIVED AND OVER WARM
GROUND...WILL CANCEL THE WINTER WEATHER ADVISORY.
STRONG NORTHERLY WINDS HAVING GUSTED AS HIGH AS 60 MPH AT THE
CHICAGO CRIB...52 MPH AT GARY...AND 48 MPH AT MIDWAY WILL
GRADUALLY DIMINISH THROUGH THE EVENING WITH THE AREA PINCHED
BETWEEN THE 1001 MB LOW NEAR CLEVELAND AND THE INCOMING 1027 MB
RIDGE. AN AIRCRAFT SOUNDING OUT OF OHARE JUST AFTER 2 PM REVEALED
40 KT WINDS AT THE TOP OF THE CHANNEL...AND NAM AND RUC SOUNDINGS
KEEP SIMILAR SPEEDS WITHIN THE BOUNDARY LAYER UNTIL A COUPLE HOURS
AFTER SUNSET. WITH STILL AN ONSHORE COMPONENT TO THE WIND...WILL
LET THE WIND ADVISORY CONTINUE. A QUICK DECOUPLING LATER IN THE
EVENING SHOULD ALLOW FOR WINDS TO COME DOWN MORE RAPIDLY ACROSS
THE ILLINOIS FORECAST AREA. ASSOCIATED LAKE SHORE FLOODING
CONCERNS WITH THE WIND ALSO CONTINUE GIVEN THE 10 TO 15 FT WAVES
FORECAST...BUT LIKELY WILL NOT LAST AS FAR INTO WEDNESDAY. CLOUDS
SHOULD SCOUR FAIRLY QUICKLY WEST OF CHICAGO THROUGH EARLY
EVENING...THEN MORE SLOWLY DOWNSTREAM OF THE LAKE. WHILE SOME LAKE
ENHANCED CLOUDS MAY OCCUR...FORECAST DEPTHS ARE VERY SHALLOW WITH
DRIER AIR BEING RAKED IN ON THE NORTHERLY WINDS...AND THUS NOT
EXPECTING ANY SHOWERS. WITH FORECAST TEMPERATURES HAVE MADE ONLY
MINOR TWEAKS...WITH READINGS ALMOST RIGHT AT NORMAL ACROSS THE
ENTIRE FORECAST AREA.
MTF
WEDNESDAY THROUGH TUESDAY...
ACTUALLY LOOKING LIKE A DAY OR TWO OF FAIRLY PLEASANT LATE NOVEMBER
WEATHER WEDNESDAY INTO THURSDAY IN WAKE OF TODAY`S SIDESWIPING BY
THE STRONG STORM SYSTEM. WARM AIR ADVECTION WILL COMMENCE WEDNESDAY
AS LOW/MID LEVEL FLOW BEGINS TO BACK IN ADVANCE OF THE NEXT NORTHERN
STREAM SHORTWAVE WHICH WILL BEGIN DROPPING INTO THE NORTHERN PLAINS.
AFTER A CHILLY MORNING TEMPS SHOULD REBOUND NICELY TOMORROW WITH
NEARLY FULL SUNSHINE.
INCREASING MID/HIGH LEVEL CLOUDINESS AND SOUTHWEST WINDS SHOULD KEEP
TEMPS A BIT WARMER TOMORROW NIGHT WHICH WILL THEN PROVIDE FOR A NICE
SPRING BOARD FOR TEMPS THURSDAY TO CLIMB BACK TO SEVERAL DEGREES
ABOVE AVERAGE. COLD FRONT WILL THEN DROP SOUTHWARD ACROSS THE CWA
LATE THURSDAY AFTERNOON/EARLY THURSDAY EVENING. STRONGEST FORCING
WITH THIS WAVE LOOKS TO PASS WELL NORTH/NORTHEAST OF THE AREA AND
WITH SCANT MOISTURE AT BEST AM HAVING A HARD TIME GETTING TOO WORKED
UP OVER OUR SNOW CHANCES THURSDAY NIGHT. ECMWF/GFS BOTH STILL TRYING
TO SPIT OUT A HUNDREDTH OF AN INCH OR SO OF QPF SO HAVE MAINTAINED
THE SLIGHT CHANCE POPS WE HAD GOING...WHICH ARE SUPPORTED BY CURRENT
MOS NUMBERS.
VERY QUICK HITTING SHOT OF FAIRLY COLD AIR THEN ARRIVES LATER
THURSDAY NIGHT AND ESPECIALLY FRIDAY. THERE STILL DOES APPEAR TO BE
A SMALL WINDOW OF OPPORTUNITY FOR SOME LAKE EFFECT SNOW SHOWERS IN
PORTER COUNTY LATE THURSDAY NIGHT INTO FRIDAY MORNING...BUT NOT
EXPECTING ANYTHING SIGNIFICANT WITH LAKE EFFECT PARAMETERS FAIRLY
MARGINAL AND DURATION BEING SHORT AS FLOW QUICKLY BACKS TO
SOUTHERLY FRIDAY AFTERNOON.
BY THIS WEEKEND OUR ATTENTION WILL TURN THE THE VIGOROUS UPPER LOW
THATS CURRENTLY OFF THE BRITISH COLUMBIA COAST. MEDIUM RANGE
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT THROUGH FRIDAY WITH THIS
SYSTEM DROPPING SOUTH AND WITH AN ANOMALOUSLY STRONG UPPER LOW (H5
HEIGHTS 3+ STANDARD DEVIATIONS BELOW AVERAGE) SETTING UP SHOP OVER
THE DESSERT SOUTHWEST BY FRIDAY. MODERATE RIDGING DOWNSTREAM OVER
THE SOUTHEASTERN CONUS SHOULD LEAVE OUR AREA IN A WEST-SOUTHWEST
FLOW ALOFT.
FORECAST CONFIDENCE THIS WEEKEND INTO EARLY NEXT WEEK IS LOW AS
MODELS OFTEN STRUGGLE WITH CUT OFF LOWS. HAVING SAID THAT...IT
APPEARS AS THOUGH THIS FIRST UPPER LOW WILL WEAKEN INTO AN OPEN WAVE
AND RIDE THE SOUTHWEST FLOW ALOFT INTO OUR AREA THIS WEEKEND...WITH
SOME DEGREE OF PHASING WITH A RESULTANT AMPLIFYING NORTHERN
STREAM TROUGH EXPECTED. WHILE DETAILS ARE MURKY...IT WOULD APPEAR
THAT OUR AREA IS IN STORE FOR INCREASINGLY UNSETTLED WEATHER LATE
SATURDAY INTO SUNDAY. WITH VARYING SOLUTIONS ABOUT THE TRACK OF
THE SURFACE SYSTEM AND RESULTANT THERMAL PROFILES IT WOULD BE
ABSURD TRYING TO PINPOINT P-TYPES FOR THE WEEKEND JUST YET.
ANOTHER...POTENTIALLY MORE SIGNIFICANT BUT BRIEF BLAST OF COLD AIR
LOOKS TO ARRIVE IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 02Z...
* NORTH TO NORTHWEST WINDS GRADUALLY DIMINISHING THIS EVENING
* NO OTHER CONCERNS OVERNIGHT
SHEA
//DISCUSSION...UPDATED 00Z...
WINDS CONTINUE TO TAPER OFF THIS EVENING AS A STRONG LOW PRESSURE
SYSTEM MOVES OUT OF THE REGION. SURFACE PRESSURE GRADIENT REMAINS
TIGHT THIS EVENING BUT WILL CONTINUE TO RELAX THROUGHOUT THE
NIGHT...WITH WINDS EVENTUALLY DIPPING BELOW 20 KT LATER TONIGHT.
CIGS WILL CONTINUE TO DECREASE THROUGH THE EVENING AND A FEW LOW
END VFR CIGS MAY PERSIST INTO THE EARLY EVENING HOURS. SURFACE
HIGH PRESSURE WILL CONTINUE TO SWING INTO THE REGION...WITH THE
DRYING TREND CONTINUING WITH GENERALLY CLEAR SKIES AND LIGHT WINDS
ANTICIPATED BY TOMORROW AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 02Z...
* MOD-HIGH CONFIDENCE IN WIND FORECAST
* HIGH CONFIDENCE IN CIG FORECAST
SHEA
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY...VFR. CHC LGT SN WITH MVFR IN THE EVENING.
* FRIDAY...CHC SHSN IN THE MORNING.
* SATURDAY...SLT CHC OF RA/SN WITH MVFR POSSIBLE.
* SUNDAY...CHC RA/SN. MVFR POSSIBLE.
* MONDAY...VFR.
SHEA
&&
.MARINE...
153 PM...LOW PRESSURE NEAR LAKE ERIE WILL CONTINUE TO LIFT
NORTHEAST TONIGHT AND INTO QUEBEC WEDNESDAY MORNING WHILE A LARGE
RIDGE OF HIGH PRESSURE EXTENDS FROM JAMES BAY SOUTHWEST INTO THE
CENTRAL PLAINS. THE GRADIENT BETWEEN THESE TWO FEATURES WILL
REMAIN STRONG BUT SLOWLY WEAKEN TONIGHT. SPEEDS/GUSTS PEAKED MID
MORNING AND EXPECT GALES IN THE 40-45 KT RANGE FOR MUCH OF THE
EVENING...BUT THREAT FOR STORM FORCE GUSTS TO 50 KT APPEARS TO
HAVE ENDED.
THE RIDGE NOTED ABOVE WILL SPLIT TONIGHT AS ONE AREA MOVES EAST
ACROSS NORTHERN QUEBEC AND THE SOUTHERN AREA DROPS SOUTH ACROSS THE
SOUTHERN PLAINS AND OHIO VALLEY WEDNESDAY. THE NORTHERN PORTION OF
THIS RIDGE WILL MOVE ACROSS LAKE MICHIGAN WEDNESDAY AFTERNOON WITH
WIND SPEEDS RAPIDLY DIMINISHING WEDNESDAY MORNING AND BECOMING
SOUTHWEST BY EVENING.
A WEAK LOW WILL DEVELOP OVER THE PLAINS WEDNESDAY NIGHT AND QUICKLY
MOVE ACROSS THE NORTHERN LAKES REGION THURSDAY AFTERNOON...
DRAGGING A COLD FRONT ACROSS THE LAKE THURSDAY NIGHT. THE GRADIENT
TIGHTENS BEHIND THIS FRONT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE PLAINS. BUT IN ADDITION TO THE TIGHTENING GRADIENT...COLDER
AIR WILL ALSO BE SPREADING ACROSS THE REGION AND EXPECT NORTHERLY
WINDS GUSTING TO AT LEAST 30 KTS WITH THE POTENTIAL FOR SOME GUSTS
TO 35 KTS. THIS HIGH THEN QUICKLY MOVES EAST ON FRIDAY WITH
SOUTHERLY WINDS DEVELOPING OVER THE LAKE FRIDAY NIGHT AS LOW
PRESSURE LIFTS NORTH ACROSS CANADA. ANOTHER COLD FRONT THEN MOVES
ACROSS THE LAKES REGION SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ006-ILZ014 UNTIL 9 PM TUESDAY.
LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM WEDNESDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 3 PM WEDNESDAY.
WIND ADVISORY...INZ001-INZ002 UNTIL 9 PM TUESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
606 PM CST TUE NOV 29 2011
.DISCUSSION...
313 PM CST
MESOSCALE/TONIGHT...
A VERY IMPRESSIVE WATER VAPOR SATELLITE LOOP THIS AFTERNOON
REVEALS THE EXPANSIVE COLD CORE LOW LIFTING NORTHEAST ACROSS THE
APPALACHIANS...JUST GRAZING THE AREA. A WELL-DEFINED DEFORMATION
AREA HAS FILLED IN WITH BANDS OF COLDER AND AT TIMES CONVECTIVE
CLOUD TOPS PROVIDING HEAVIER AND FROZEN PRECIPITATION ACROSS PARTS
OF NORTHERN IN. THE DUAL POLARIZATION RADAR EVEN DETECTED THE
PRECIPITATION TYPE SWITCH AT 7000-9000 FT. THIS HAS BEEN OBSERVED
AT THE GROUND JUST TO THE SOUTH AND EAST OF THE FORECAST AREA IN
LAFAYETTE /WHERE SLUSHY ACCUMULATION HAS OCCURRED ON GRASSY
SURFACES/. THE 13KM RUC SOUNDINGS ACROSS BENTON AND JASPER
COUNTIES CONTINUE TO SHOW A GRADUAL SHRINKING OF THE NEAR-SURFACE
WARM LAYER TO ALLOW FOR A MIX TO MAKE IT TO THE GROUND FOR
POSSIBLY A COUPLE HOURS. THAT COUPLE OF HOURS LOOKS TO BE IT GIVEN
SATELLITE AND SHORT TERM MODEL TRENDS TO SHIFT THE FORCING EAST.
GIVEN THAT ANY TRANSITION WILL BE SO SHORT LIVED AND OVER WARM
GROUND...WILL CANCEL THE WINTER WEATHER ADVISORY.
STRONG NORTHERLY WINDS HAVING GUSTED AS HIGH AS 60 MPH AT THE
CHICAGO CRIB...52 MPH AT GARY...AND 48 MPH AT MIDWAY WILL
GRADUALLY DIMINISH THROUGH THE EVENING WITH THE AREA PINCHED
BETWEEN THE 1001 MB LOW NEAR CLEVELAND AND THE INCOMING 1027 MB
RIDGE. AN AIRCRAFT SOUNDING OUT OF OHARE JUST AFTER 2 PM REVEALED
40 KT WINDS AT THE TOP OF THE CHANNEL...AND NAM AND RUC SOUNDINGS
KEEP SIMILAR SPEEDS WITHIN THE BOUNDARY LAYER UNTIL A COUPLE HOURS
AFTER SUNSET. WITH STILL AN ONSHORE COMPONENT TO THE WIND...WILL
LET THE WIND ADVISORY CONTINUE. A QUICK DECOUPLING LATER IN THE
EVENING SHOULD ALLOW FOR WINDS TO COME DOWN MORE RAPIDLY ACROSS
THE ILLINOIS FORECAST AREA. ASSOCIATED LAKE SHORE FLOODING
CONCERNS WITH THE WIND ALSO CONTINUE GIVEN THE 10 TO 15 FT WAVES
FORECAST...BUT LIKELY WILL NOT LAST AS FAR INTO WEDNESDAY. CLOUDS
SHOULD SCOUR FAIRLY QUICKLY WEST OF CHICAGO THROUGH EARLY
EVENING...THEN MORE SLOWLY DOWNSTREAM OF THE LAKE. WHILE SOME LAKE
ENHANCED CLOUDS MAY OCCUR...FORECAST DEPTHS ARE VERY SHALLOW WITH
DRIER AIR BEING RAKED IN ON THE NORTHERLY WINDS...AND THUS NOT
EXPECTING ANY SHOWERS. WITH FORECAST TEMPERATURES HAVE MADE ONLY
MINOR TWEAKS...WITH READINGS ALMOST RIGHT AT NORMAL ACROSS THE
ENTIRE FORECAST AREA.
MTF
WEDNESDAY THROUGH TUESDAY...
ACTUALLY LOOKING LIKE A DAY OR TWO OF FAIRLY PLEASANT LATE NOVEMBER
WEATHER WEDNESDAY INTO THURSDAY IN WAKE OF TODAY`S SIDESWIPING BY
THE STRONG STORM SYSTEM. WARM AIR ADVECTION WILL COMMENCE WEDNESDAY
AS LOW/MID LEVEL FLOW BEGINS TO BACK IN ADVANCE OF THE NEXT NORTHERN
STREAM SHORTWAVE WHICH WILL BEGIN DROPPING INTO THE NORTHERN PLAINS.
AFTER A CHILLY MORNING TEMPS SHOULD REBOUND NICELY TOMORROW WITH
NEARLY FULL SUNSHINE.
INCREASING MID/HIGH LEVEL CLOUDINESS AND SOUTHWEST WINDS SHOULD KEEP
TEMPS A BIT WARMER TOMORROW NIGHT WHICH WILL THEN PROVIDE FOR A NICE
SPRING BOARD FOR TEMPS THURSDAY TO CLIMB BACK TO SEVERAL DEGREES
ABOVE AVERAGE. COLD FRONT WILL THEN DROP SOUTHWARD ACROSS THE CWA
LATE THURSDAY AFTERNOON/EARLY THURSDAY EVENING. STRONGEST FORCING
WITH THIS WAVE LOOKS TO PASS WELL NORTH/NORTHEAST OF THE AREA AND
WITH SCANT MOISTURE AT BEST AM HAVING A HARD TIME GETTING TOO WORKED
UP OVER OUR SNOW CHANCES THURSDAY NIGHT. ECMWF/GFS BOTH STILL TRYING
TO SPIT OUT A HUNDREDTH OF AN INCH OR SO OF QPF SO HAVE MAINTAINED
THE SLIGHT CHANCE POPS WE HAD GOING...WHICH ARE SUPPORTED BY CURRENT
MOS NUMBERS.
VERY QUICK HITTING SHOT OF FAIRLY COLD AIR THEN ARRIVES LATER
THURSDAY NIGHT AND ESPECIALLY FRIDAY. THERE STILL DOES APPEAR TO BE
A SMALL WINDOW OF OPPORTUNITY FOR SOME LAKE EFFECT SNOW SHOWERS IN
PORTER COUNTY LATE THURSDAY NIGHT INTO FRIDAY MORNING...BUT NOT
EXPECTING ANYTHING SIGNIFICANT WITH LAKE EFFECT PARAMETERS FAIRLY
MARGINAL AND DURATION BEING SHORT AS FLOW QUICKLY BACKS TO
SOUTHERLY FRIDAY AFTERNOON.
BY THIS WEEKEND OUR ATTENTION WILL TURN THE THE VIGOROUS UPPER LOW
THATS CURRENTLY OFF THE BRITISH COLUMBIA COAST. MEDIUM RANGE
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT THROUGH FRIDAY WITH THIS
SYSTEM DROPPING SOUTH AND WITH AN ANOMALOUSLY STRONG UPPER LOW (H5
HEIGHTS 3+ STANDARD DEVIATIONS BELOW AVERAGE) SETTING UP SHOP OVER
THE DESSERT SOUTHWEST BY FRIDAY. MODERATE RIDGING DOWNSTREAM OVER
THE SOUTHEASTERN CONUS SHOULD LEAVE OUR AREA IN A WEST-SOUTHWEST
FLOW ALOFT.
FORECAST CONFIDENCE THIS WEEKEND INTO EARLY NEXT WEEK IS LOW AS
MODELS OFTEN STRUGGLE WITH CUT OFF LOWS. HAVING SAID THAT...IT
APPEARS AS THOUGH THIS FIRST UPPER LOW WILL WEAKEN INTO AN OPEN WAVE
AND RIDE THE SOUTHWEST FLOW ALOFT INTO OUR AREA THIS WEEKEND...WITH
SOME DEGREE OF PHASING WITH A RESULTANT AMPLIFYING NORTHERN
STREAM TROUGH EXPECTED. WHILE DETAILS ARE MURKY...IT WOULD APPEAR
THAT OUR AREA IS IN STORE FOR INCREASINGLY UNSETTLED WEATHER LATE
SATURDAY INTO SUNDAY. WITH VARYING SOLUTIONS ABOUT THE TRACK OF
THE SURFACE SYSTEM AND RESULTANT THERMAL PROFILES IT WOULD BE
ABSURD TRYING TO PINPOINT P-TYPES FOR THE WEEKEND JUST YET.
ANOTHER...POTENTIALLY MORE SIGNIFICANT BUT BRIEF BLAST OF COLD AIR
LOOKS TO ARRIVE IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* NORTH TO NORTHWEST WINDS GRADUALLY DIMINISHING THIS EVENING
* NO OTHER CONCERNS OVERNIGHT
SHEA
//DISCUSSION...UPDATED 00Z...
WINDS CONTINUE TO TAPER OFF THIS EVENING AS A STRONG LOW PRESSURE
SYSTEM MOVES OUT OF THE REGION. SURFACE PRESSURE GRADIENT REMAINS
TIGHT THIS EVENING BUT WILL CONTINUE TO RELAX THROUGHOUT THE
NIGHT...WITH WINDS EVENTUALLY DIPPING BELOW 20 KT LATER TONIGHT.
CIGS WILL CONTINUE TO DECREASE THROUGH THE EVENING AND A FEW LOW
END VFR CIGS MAY PERSIST INTO THE EARLY EVENING HOURS. SURFACE
HIGH PRESSURE WILL CONTINUE TO SWING INTO THE REGION...WITH THE
DRYING TREND CONTINUING WITH GENERALLY CLEAR SKIES AND LIGHT WINDS
ANTICIPATED BY TOMORROW AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MOD-HIGH CONFIDENCE IN WIND FORECAST
* HIGH CONFIDENCE IN CIG FORECAST
SHEA
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY...VFR. CHC LGT SN WITH MVFR IN THE EVENING.
* FRIDAY...CHC SHSN IN THE MORNING.
* SATURDAY...SLT CHC OF RA/SN WITH MVFR POSSIBLE.
* SUNDAY...CHC RA/SN. MVFR POSSIBLE.
* MONDAY...VFR.
SHEA
&&
.MARINE...
153 PM...LOW PRESSURE NEAR LAKE ERIE WILL CONTINUE TO LIFT
NORTHEAST TONIGHT AND INTO QUEBEC WEDNESDAY MORNING WHILE A LARGE
RIDGE OF HIGH PRESSURE EXTENDS FROM JAMES BAY SOUTHWEST INTO THE
CENTRAL PLAINS. THE GRADIENT BETWEEN THESE TWO FEATURES WILL
REMAIN STRONG BUT SLOWLY WEAKEN TONIGHT. SPEEDS/GUSTS PEAKED MID
MORNING AND EXPECT GALES IN THE 40-45 KT RANGE FOR MUCH OF THE
EVENING...BUT THREAT FOR STORM FORCE GUSTS TO 50 KT APPEARS TO
HAVE ENDED.
THE RIDGE NOTED ABOVE WILL SPLIT TONIGHT AS ONE AREA MOVES EAST
ACROSS NORTHERN QUEBEC AND THE SOUTHERN AREA DROPS SOUTH ACROSS THE
SOUTHERN PLAINS AND OHIO VALLEY WEDNESDAY. THE NORTHERN PORTION OF
THIS RIDGE WILL MOVE ACROSS LAKE MICHIGAN WEDNESDAY AFTERNOON WITH
WIND SPEEDS RAPIDLY DIMINISHING WEDNESDAY MORNING AND BECOMING
SOUTHWEST BY EVENING.
A WEAK LOW WILL DEVELOP OVER THE PLAINS WEDNESDAY NIGHT AND QUICKLY
MOVE ACROSS THE NORTHERN LAKES REGION THURSDAY AFTERNOON...
DRAGGING A COLD FRONT ACROSS THE LAKE THURSDAY NIGHT. THE GRADIENT
TIGHTENS BEHIND THIS FRONT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE PLAINS. BUT IN ADDITION TO THE TIGHTENING GRADIENT...COLDER
AIR WILL ALSO BE SPREADING ACROSS THE REGION AND EXPECT NORTHERLY
WINDS GUSTING TO AT LEAST 30 KTS WITH THE POTENTIAL FOR SOME GUSTS
TO 35 KTS. THIS HIGH THEN QUICKLY MOVES EAST ON FRIDAY WITH
SOUTHERLY WINDS DEVELOPING OVER THE LAKE FRIDAY NIGHT AS LOW
PRESSURE LIFTS NORTH ACROSS CANADA. ANOTHER COLD FRONT THEN MOVES
ACROSS THE LAKES REGION SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND ADVISORY...ILZ006-ILZ014 UNTIL 9 PM TUESDAY.
LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM WEDNESDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 3 PM WEDNESDAY.
WIND ADVISORY...INZ001-INZ002 UNTIL 9 PM TUESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
919 PM EST TUE NOV 29 2011
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
THE UPPER LOW WILL MOVE INTO THE NORTHEAST USA BY WEDNESDAY
MORNING...ENDING THE PRECIPITATION ACROSS THE AREA. A COLD FRONT
WILL MOVE INTO THE AREA FOR THE WEEKEND INTO EARLY NEXT WEEK
BRINGING ANOTHER CHANCE FOR PRECIPITATION.
&&
.NEAR TERM /REST OF THIS AFTERNOON AND TONIGHT/...
FOCUS IS ON SNOW EVENT. MODELS ARE SIMILAR ENOUGH THAT A BLEND CAN
BE USED.
THERMAL PROFILES HAVE COOLED ENOUGH THAT MOST OF THE PRECIPITATION
IS SNOW ACROSS THE FORECAST AREA AT 20Z. EXCEPTIONS ARE WHERE
PRECIPITATION IS LIGHTEST WHERE IT IS STILL RAIN. THUS EXPECT SNOW
AS THE MAIN PRECIPITATION TYPE FOR THE REST OF THE PERIOD.
HEAVIEST SNOW IS FALLING IN AREAS OF STRONGEST FRONTOGENETICAL
FORCING AT 850 AND 700 MB. LATEST RUC FORECAST IS FOR THESE
HEAVIER BANDS TO REMAIN RELATIVELY STATIONARY FOR THE NEXT FEW
HOURS BEFORE MOVING EAST THIS EVENING. THESE BANDS ARE MAINLY
WHERE THE WINTER WEATHER ADVISORY ALREADY EXISTS.
HOWEVER RECENT TRENDS ARE TO GO A LITTLE FARTHER SOUTH WITH THE
HEAVIER SNOW...SO WILL EXPAND THE ADVISORY ONE MORE TIER OF
COUNTIES SOUTH INTO INDIANAPOLIS PROPER....ESPECIALLY SINCE SNOW
WILL BE FALLING IN RUSH HOUR THERE.
BASED ON WHAT HAS ALREADY FALLEN...SOME MELTING...AND WHAT WILL
FALL THIS EVENING KEPT STORM TOTAL AMOUNTS NEAR 4 INCHES ACROSS
THE FAR NORTH TO 1 TO 2 INCHES ALONG I-70 AND LOWER AMOUNTS SOUTH.
FORCING QUICKLY EXITS THE AREA THIS EVENING SO WILL ONLY GO
CHANCE POPS AFTER 06Z.
MOS LOOKS TOO COLD WITH LOW TEMPERATURES GIVEN EXPECTED CLOUD
COVER...SO WENT CLOSER TO ENSEMBLE MEANS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
FOCUS IS ON SKY EARLY THEN ON TEMPERATURES. MODELS ARE SIMILAR SO
USED A BLEND.
FORCING WILL BE FAR ENOUGH EAST BY WEDNESDAY MORNING SO THAT CAN
GO DRY ALL AREAS. LOOKING AT LOW LEVEL RELATIVE HUMIDITY
FORECASTS....BELIEVE THAT LOW CLOUDS WILL HANG AROUND UNTIL MID
DAY...ESPECIALLY EAST. THESE WILL KEEP TEMPERATURES CLOSER TO THE
COOLER MAV MOS MOST AREAS.
HIGH PRESSURE WILL THEN PROVIDE DRY CONDITIONS INTO THURSDAY
NIGHT. MAV MOS LOOKS LIKE A COOL OUTLIER FOR LOWS WEDNESDAY NIGHT
SO WENT CLOSER TO THE MET AND ENSEMBLE MEANS. USED A BLEND OF MOS
FOR THURSDAY.
A FRONT WILL MOVE INTO THE AREA LATE THURSDAY NIGHT INTO
FRIDAY...BUT FORCING IS MINIMAL WITH IT AS BEST ENERGY REMAINS
WELL TO THE NORTH. ALSO MOISTURE IS WEAK AS WELL...SO WENT DRY ON
FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MAIN LONG TERM FOCUS WILL BE A DEEPENING UPPER TROUGH WHICH MOVES
FROM THE NORTHERN PLAINS SATURDAY TO THE GREAT LAKES BY MONDAY AND
EASTERN GREAT LAKES TO WEST VIRGINIA BY TUESDAY. MODELS ARE A
LITTLE MORE PROGRESSIVE THIS RUN...BUT STILL KEEP PRECIP JUST TO
OUR NORTHWEST SATURDAY. PRECIP WILL BEGIN MOST AREAS LATE SATURDAY
NIGHT AND MAINLY AS LIGHT RAIN. BUT I WOULD NOT RULE OUT A BRIEF
PERIOD OF SNOW IN OUR NORTH WHEN IT FIRST STARTS.
AS MENTIONED ABOVE MODELS HAVE TRENDED MORE PROGRESSIVE AND THE
TRAILING COLD FRONT SHOULD BE FAR ENOUGH EAST BY MONDAY FOR MOST
AREAS TO BE DRY BY THEN. SOME MODELS INCLUDING HPC INDICATE A WEAK
SECONDARY SYSTEM WILL MOVE ACROSS THE SOUTHERN GREAT LAKES MONDAY
NIGHT AND WILL ADD A SLIGHT CHANCE OF SNOW SHOWERS ACROSS OUR FAR
NORTH. OTHERWISE...DRY AND COLD WEATHER WILL BE THE RULE AFTER THIS
UPCOMING WEEKEND.
&&
.AVIATION /DISCUSSION FOR THE 300300Z KIND TAF UPDATE/...
PRECIPITATION CONTINUES TO DIMINISH AS DEFORMATION ZONE WEAKENS.
BASED ON RADAR TRENDS...WILL HOLD ONTO THE RAIN/SNOW...AS WELL AS
THE IFR CEILINGS...AT KIND FOR ANOTHER HOUR OR SO. MAY STILL BE A
BRIEF PERIOD OF IFR VISIBILITY RESTRICTIONS AS WELL...BUT NOT
EXPECTED TO LAST LONG ENOUGH TO KEEP IN THE FORECAST ANY LONGER.
SURFACE WINDS HAVE TEMPORARILY DROPPED OFF...BUT SHOULD INCREASE
AGAIN OVER THE NEXT COUPLE OF HOURS. PREVIOUS DISCUSSION FOLLOWS.
PRECIPITATION AREA HAS BEGUN TO SHRINK IN BOTH COVERAGE AND
INTENSITY OVER THE PAST HOUR OR SO AS LIFT WITHIN THE DEFORMATION
ZONE WEAKENS AND PUSHES OFF TO THE NORTHEAST. PRECIPITATION HAS
MAINLY BEEN A MIX OF RAIN/SNOW WITH THE SNOW LINKED TO THE STRONGER
RETURNS ON THE RADAR. THIS PROCESS EXPECTED TO CONTINUE THIS EVENING
AS DEFORMATION ZONE WEAKENS. APPEARS PRECIPITATION WILL BE OVER AT
KHUF/KLAF BY ISSUANCE TIME...AND BY 300200Z-300300Z AT KIND/KBMG.
PRECIPITATION MAY STILL BE HEAVY ENOUGH FOR IFR VISIBILITY
RESTRICTIONS AT KIND/KBMG UNTIL ABOUT 300100Z.
CEILINGS EXPECTED TO IMPROVE RATHER RAPIDLY LATER THIS EVENING AS
THE PRECIPITATION ENDS. ALREADY SEEING CEILINGS 030-040 OBSERVED
JUST ACROSS THE ILLINOIS STATE LINE. EXPECTING THE LINGERING IFR
CEILINGS TO LIFT INTO A 030-040 DECK BY 300300Z.
SURFACE WIND GUSTS UP TO ABOUT 25 KTS FROM 320-350 HEADINGS EXPECTED
THROUGHOUT MOST OF THE EVENING...WITH THESE GUSTS DIMINISHING AFTER
300600Z AS PRESSURE GRADIENT LOOSENS UP.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR INZ021-
028>031-035>049.
&&
$$
SYNOPSIS...50/AH
NEAR TERM...50/AH
SHORT TERM...50/AH
LONG TERM....JH
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
720 PM EST TUE NOV 29 2011
.UPDATE/AVIATION...
SUBSTANTIAL CHNGS WRT KSBN AS PROLIFIC MESOBANDED/CONVECTIVE
SNOWFALL TO MOST LKLY RMN EAST OF AIRFLD PER HRRR ANALYSIS. IN
ADDITION...RECENT STRONG SFC PRES RISES ACRS NRN IN SUGGESTS SFC LOW
AND ASSOCD BANDING TO JUMP EWD NEXT FEW HRS. FURTHER SUBSTANTIATING
HRRR IS WV IMAGERY SHOWING TIGHTLY CYCLCLY WOUND DRY SLOT NOW INTO
KFWA WITH ERLIER LULL/IMPROVEMENT TO 7SM...OCCLSN FCST TO SHIFT EWD
OF MIDLVL CIRC CENTER NEAR KAOH ATTM INTO ERN OH BY 06 UTC. FILLING
PRECIP ANTICIPATED TO RETURN EWD INTO KFWA AFT 01 UTC WITH POTNL FOR
INTENSE BAND FM KHAI-KASW-5W KOKK TO SHIFT EWD TO KFWA 02-05 UTC
WITH PSBL LIFR MET CONDS. AS ENTIRE SYSTEM LIFTS OUT TOWARD
DAYBREAK...SHARP LWRG OF SUBSIDENCE INVERSION PER KOXI PROXIMITY
LAPS SNDG...TO BRING ABRUPT END OF SNOW W-E ACRS NRN IN...NLT 03 UTC
KSBN TO KFWA AROUND 05 UTC. STRONG PRES RISES SHOULD BRING PD OF HIR
GUSTS INTO MID/UPR 20S KT RANGE...THOUGH IN ABSENCE OF STRONG CAA
AND LWRG SUBSIDENCE INVERSION THIS UPTICK SHOULD REMAIN
SHORT-LIVED...RELAXING AFTR MIDNIGHT.
ANTICIPATE UPDATE WITHIN NEXT HOUR TO TRIM WRN PERIPHERY ADVISORY
COUNTIES/LKLY DOWNGRADE SOUTH OF KOS/WHITLEY/ALLEN IN COUNTIES TO
ADVISORY. ALL ANTICIPATED CHANGES WL LARGELY BE IN LOCK STEP OF HRRR
3KM HRLY/15 MIN MESODATA...ASSUMPTIVE OF WELL CORRELATED RADAR/METAR
OBS TRENDS.
&&
.SHORT TERM.../TONIGHT/
...FIRST WIDESPREAD SNOW OF THE SEASON COMMENCING...
UPDATES ISSUED EARLIER GENERALLY ON TRACK WITH RAPID COOLING OF
COLUMN OCCURRING BETWEEN 18 AND 20Z. MANY LOCATIONS NOW REPORTING
SNOW OR A MIX OF SNOW/SLEET/RAIN. SNOW AMOUNTS INITIALLY MAY BE ON
LIGHTER SIDE WITH MELTING OCCURRING ON SLIGHTLY WARMER SURFACES.
HOWEVER AS UPPER LOW APPROACHES LATE THIS AFTERNOON AND EVENING AND
MESOBANDING BETTER ESTABLISHES SNOWFALL RATES SHOULD INCREASE ACROSS
MUCH OF THE WARNING AREA. SPORADIC LIGHTNING STRIKES SEEN SW OF THE
AREA IN MAIN MESOBAND WHICH WILL TRANSLATE THROUGH THE AREA INTO
TONIGHT.
HEAVIEST SNOWFALL WILL OCCUR BETWEEN 22Z TUES AND 6Z WEDS AS MAIN
DEFORMATION ZONE SHIFTS ACROSS THE FORECAST AREA. SEVERAL RUNS OF
THE HRRR HAVE SHOWN THE MAIN SWATH OF HEAVIER SNOW TO TAKE SHAPE
EITHER SIDE OF A MARION TO ANGOLA TO HILLSDALE LINE. THIS MODEL
DEPICTS UPWARDS OF 8 TO 12 INCHES OF SNOWFALL. THINK THIS IS LIKELY
OVER DONE WITH GREATER CONFIDENCE IN DECENT AREA OF 4 TO 7 INCHES OF
SNOW WITH AMOUNTS APPROACHING 8 ESPECIALLY ACROSS PORTIONS OF
NORTHEASTERN INDIANA INTO FAR SOUTHERN LWR MI AND FAR NW OHIO. WILL
LET EVE SHIFT MONITOR TRENDS OF AMOUNTS AND HEAVIEST BAND AND ADJUST
HEADLINES ACCORDINGLY. TEMPS WILL CONTINUE TO FALL AND BOTTOM OUT IN
THE UPPER 20S TO AROUND 30.
WINDS WILL ALSO INCREASE TONIGHT AS THE TIGHTLY WRAPPED LOW
CONTINUES TO MOVE AWAY. AS WE GET INTO THE OVERNIGHT HOURS THIS
COULD CAUSE SOME DRIFTING AND LOW BLOWING OF THE SNOW...BUT GIVEN
THE INITIAL WET CONTENT...NOT EXPECTED TO BE A SIG IMPACT.
&&
.LONG TERM...
MINOR ADJUSTMENTS TO THE TEMPERATURES WEDNESDAY AND WEDNESDAY NIGHT
TO TAKE INTO ACCOUNT OUR LATEST SNOWFALL FORECASTS AND EXPECTED
CLOUD COVER. HAVE NUDGED TEMPS DOWN FOR THE MAX T AND UP FROM
PREVIOUS GRIDS FOR OVERNIGHT LOW. WITH CYCLONIC FLOW OVER THE REGION
EXPECT THAT CLOUDS WILL PERSIST AND HAVE INCREASED CLOUD COVER - BUT
MAY NOT HAVE INCREASED ENOUGH FOR THURSDAY.
LONGWAVE PATTERN IS BEGINNING TO BE MUCH MORE AMPLIFIED AND THIS
SETS UP A PROGRESSIVE PATTERN OVER THE GREAT LAKES REGION BEGINNING
THURSDAY WITH ANOTHER VIGOROUS SHORTWAVE TO TO DIVE OUT OF THE
NORTHERN PLAINS BY SATURDAY...LEADING TO ANOTHER SHOT OF COLDER AIR
POISED TO DROP OUT OF THE CANADIAN PLAINS THIS COMING WEEKEND.
WITH A BRIEF WARMING TREND THU/FRI TEMPS WILL BE BELOW NORMAL
BEGINNING SAT-NEXT TUES.
WITH THE INCOMING SHORTWAVE ON SATURDAY...HAVE INCREASED POP TO MORE
CLOSELY MATCH SURROUNDING OFFICES AND WOULD EXPECT TO SEE ANOTHER
ACCUMULATING SNOWFALL DURING THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WARNING UNTIL 1 AM EST WEDNESDAY FOR INZ006>009-
015>018-022>027-032>034.
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ WEDNESDAY
FOR INZ004-005-012>014-020.
MI...WINTER STORM WARNING UNTIL 1 AM EST WEDNESDAY FOR MIZ080-081.
WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MIZ078-079.
OH...WINTER STORM WARNING UNTIL 1 AM EST WEDNESDAY FOR
OHZ001-002-004-015.
LM...GALE WARNING UNTIL 10 AM EST WEDNESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...FISHER
LONG TERM...LEWIS
AVIATION...MURPHY
UPDATE...MURPHY
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1123 PM CST SUN NOV 27 2011
.UPDATE 28/06Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
PRIMARY CONCERN REMAINS LOW CLOUD TRENDS. MODELS HAVE HAD A POOR
TIME INITIALIZING AND RESOLVING STRATUS...BUT LATEST RUC SEEMS TO
HAVE THE BEST HANDLE ON THINGS BEING MORE PERSISTENT. THIS
GENERALLY AGREES WITH EXTRAPOLATION NUDGING CLEARING LINE SLOWLY
EASTWARD INTO CENTRAL IA TOWARD MIDNIGHT AND SUGGESTING CLEARING TO
OUR ERN FORECAST AREA BY MORNING BASED ON FURTHER EXTRAPOLATION.
LOW CONFIDENCE IN THESE TRENDS WILL ALSO SPILL OVER INTO MIN TEMPS.
HAVE GENERALLY FOLLOWED GUIDANCE WEST WHERE AIRMASS IS ADEQUATELY
REPRESENTED BY MODELS. HOWEVER NUDGED TEMPS UP ABOVE EVEN THE
WARMEST GUIDANCE EAST WHERE PROLONGED CLOUD COVER IS ANTICIPATED.
CLEARING PROGRESSION WILL MAKE ALL THE DIFFERENCE...SO EXPECT
CONSIDERABLE GRADIENT IN MIN TEMPS.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
FAIRLY BENIGN MID/LONG RANGE WITH LITTLE IN THE WAY OF PRECIPITATION
CHANCES UNTIL THE NEXT WEEKEND. NEXT WEATHER SYSTEM TO IMPACT IOWA
WILL BE A POSITIVELY TILTED SHORTWAVE MOVING ONSHORE IN THE PACIFIC
NORTHWEST AT THIS TIME. THE BRUNT OF THE SHORTWAVE ENERGY
ASSOCIATED WITH THE WAVE WILL PASS TO THE EAST WELL NORTH OF IOWA.
THE SOUTHERN PART OF THE SHORTWAVE SHOULD MERGE WITH LARGE UPPER LOW
OVER THE OHIO VALLEY BY 18Z TUESDAY. THE COLD FRONT ASSOCIATED WITH
THE SHORTWAVE SHOULD CROSS IOWA MONDAY NIGHT. ONLY LIMITED FORCING
AND MOISTURE SHOULD KEEP THE SENSIBLE WEATHER IMPACT LIMITED TO
INCREASED WINDS...CLOUDS AND MODEST COOLING BUT NO PRECIPITATION.
ON MONDAY...THERE SHOULD BE VERY LITTLE BOUNDARY LAYER FLOW WITH THE
CENTER OF A WEAK SURFACE HIGH PRESSURE SYSTEM IN THE AREA. MODEL
SOUNDINGS SHOW A VERY STRONG INVERSION WITH MINIMAL MIXING.
THEREFORE...EXPECT COOL TEMPERATURES WITH LIGHT SURFACE WINDS.
FOR THURSDAY AND BEYOND INTO NEXT WEEKEND...THE GFS AND ECMWF ONCE
AGAIN DIVERGE IN THEIR SOLUTIONS OF THE WEATHER OVER THE UPPER
MIDWEST. THE ECMWF LIFTS OUT AND WEAKENS THE SOUTHWEST UNITED
STATES UPPER LOW INTO THE PLAINS BY NEXT SATURDAY EVENING. THIS
WILL BRING THE NEXT CHANCE OF PRECIPITATION TO IOWA. IT IS FAR TO
EARLY TO DETERMINE THE EXTENT OF THE PRECIPITATION CHANCES OR THE
PRECIPITATION TYPE. FOR NOW...INTRODUCED SMALL POPS SATURDAY NIGHT
INTO SUNDAY.
&&
.AVIATION DISCUSSION...28/06Z
ST SHIELD CONTINUES TO SLOW...THOUGH SOME EROSION HAS TAKEN PLACE
OVER SOUTH CENTRAL MN AND MAY HELP TO ERODE PORTIONS OF NORTHERN
IOWA SHIELD. WILL NOT BANK ON THIS...HOWEVER. ELSEWHERE...BACK EDGE
HAS COME TO A STANDSTILL AS LIGHT NORTH NORTHEAST WINDS PREVAIL FOR
NOW. EXPECT SOME EASTWARD PROGRESS OVERNIGHT...BUT HAVE SLOWED
CLEARING EVEN MORE FROM PREVIOUS UPDATE WITH EASTERN TAF SITES NOW
CLEARING CLOSER TO 17 TO 18Z...WHILE WEST AND CENTRAL SITES SHOULD
CLEAR BETWEEN 06 AND 08Z. H700 RIDGE INCREASING ALOFT AND
ANTICYCLONIC CURVATURE SHOULD...IN THEORY...HELP THE PROCESS ALONG
OVERNIGHT INTO THE EARLY MORNING HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
AVIATION...REV
LONG TERM...JOHNSON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
529 PM CST TUE NOV 29 2011
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE FORECAST (TONIGHT AND WEDNESDAY)...
20Z WATER VAPOR IMAGERY AND ASSOCIATED 500 MB RUC ANALYSIS SHOWS A
DEEP CUT OFF LOW PRESSURE SYSTEM SLOWLY MOVING NORTHEASTWARD THROUGH
THE OHIO RIVER VALLEY...BRINGING NORTHWESTERLY MID LEVEL FLOW OVER
THE CENTRAL U.S. A SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST
FLOW IS CURRENTLY PUSHING THROUGH THE AREA...HOWEVER MEAGER LIFT
FROM THIS QUICKLY MOVING SHORTWAVE WILL ONLY BRING SOME SCATTERED
HIGH CLOUDS FOR THIS AFTERNOON. AT THE SURFACE A SURFACE RIDGE OF
HIGH PRESSURE CURRENTLY SITS OVER CENTRAL KANSAS CREATING TIGHT
GRADIENT WITH SUBSEQUENT GUSTY NORTH-NORTHWEST WINDS ACROSS FAR
EASTERN KANSAS. A NARROW BAND OF DRY AIR HAS MOVED INTO NORTH
CENTRAL KANSAS AS DEWPOINTS HAVE MIXED INTO THE SINGLE
DIGITS...HOWEVER DUE TO THE LIGHT WINDS NEAR THE CENTER OF THE
SURFACE HIGH...FIRE DANGER IS NOT VERY HIGH IN THIS AREA DESPITE THE
VERY DRY AIR.
OVERNIGHT THE SURFACE RIDGE MOVES OVER NORTHEAST KANSAS CAUSING
WINDS TO GO CALM. WITH SKIES CLEARING OUT RADIATIONAL COOLING WILL
ALLOW TEMPERATURES TO DROP INTO THE LOWER TO MID 20S. WOULD HAVE
GONE A LITTLE COOLER IN NORTH CENTRAL KANSAS BUT SOUTHERLY FLOW
ALONG THE WESTERN EDGE OF THE EASTWARD MOVING SURFACE RIDGE WILL
ALLOW FOR SOME WEAK WARM AIR ADVECTION AS WELL AS SOME BOUNDARY
LAYER MIXING. THESE FACTORS WILL HELP TO KEEP TEMPERATURES A LITTLE
WARMER THAN AREAS FURTHER EAST. LOW LYING AREAS AND RIVER VALLEYS
EAST OF HIGHWAY 75 COULD SEE TEMPS DROP INTO THE UPPER TEENS AS
SOUTHERLY FLOW WILL LIKELY NOT BEGIN IN THESE AREAS UNTIL EARLY WED
MORNING.
WEDNESDAY WILL BRING ANOTHER MOSTLY CLEAR DAY WITH SLIGHTLY WARMER
TEMPERATURES THAN TUESDAY. SOUTHERLY FLOW WILL ALLOW FOR WARM AIR
ADVECTION EAST OF A DEEPENING SURFACE TROUGH WHICH WILL COME OFF THE
WESTERN HIGH PLAINS AND MOVE EAST INTO THE CENTRAL PLAINS. UTILIZED
A MIX DOWN METHOD FROM THE 900 MB LEVEL FOR WEDNESDAYS HIGHS.
TIGHTENING SURFACE PRESSURE GRADIENT BETWEEN THE DEEPENING LOW AND
THE DEPARTING SURFACE HIGH WILL CAUSE THE SOUTHERLY WINDS TO PICK UP
IN INTENSITY THROUGHOUT THE DAY ON WEDNESDAY.
JL
EXTENDED RANGE FORECAST (WEDNESDAY NIGHT THROUGH TUESDAY)...
AN UPPER LEVEL TROUGH WILL DIG SOUTHWARD ACROSS THE WESTERN CONUS
INTO THE DESERT SOUTHWEST BY THURSDAY EVENING. A MINOR H5 WILL MOVE
EAST ACROSS THE NORTHERN AND CENTRAL PLAINS WEDNESDAY NIGHT.
LOW-LEVEL CAA ACROSS THE NORTHERN PLAINS WILL CAUSE A SURFACE COLD
FRONT TO PUSH SOUTHWARD ACROSS THE CWA THURSDAY MORNING. HIGHS MAY
OCCUR DURING THE MID AND LATE MORNING HOURS ON THURSDAY ACROSS
SOUTHEAST KS...WITH TEMPERATURES HOLDING STEADY OR SLOWLY FALLING
INTO THE LOWER 40S BY AFTERNOON. NORTH WINDS WILL INCREASE 20 TO 25
MPH WITH GUSTS OF 35 TO 45 MPH BEHIND THE COLD FRONT. THERE MAY BE
SOME SNOW FLURRIES EARLY THURSDAY MORNING ACROSS THE NORTHERN
COUNTIES OF THE CWA.
FRIDAY...WILL BE COOL WITH INCREASING HIGH CLOUDINESS. WINDS WILL
SHIFT TO THE SOUTHEAST BY LATE AFTERNOON AS A LEE SFC TROUGH DEEPENS
ACROSS THE HIGH PLAINS. HIGHS ON FRIDAY WILL ONLY REACH THE MID TO
UPPER 30S. THE NAM MODEL SOLUTION HAS BEEN VERY INCONSISTENT AND
ERRONEOUS THE PAST 48 HOURS. THE NAM IS WAY TOO PROGRESSIVE LIFTING
THE CLOSED UPPER LOW INTO THE SOUTHERN HIGH PLAINS LATE FRIDAY
AFTERNOON. IF FOR SOME REASON IT WERE TO VERIFY THEN PRECIP MAY
BEGIN DEVELOPING ACROSS THE SOUTHERN COUNTIES OF THE CWA LATE FRIDAY
AFTERNOON AND SPREAD NORTHWARD INTO THE EARLY EVENING HOURS. ALL
OTHER OPERATIONAL NUMERICAL MODELS SHOW THE CLOSED UPPER LOW
REMAINING ACROSS THE DESERT SOUTHWEST INTO FRIDAY NIGHT.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...A PIECE OF THE UPPER LOW
ACROSS THE DESERT SOUTHWEST WILL LIFT NORTHEAST INTO THE CENTRAL
PLAINS ON SATURDAY. THE ECMWF MODEL SHOWS STRONG WAA DEVELOPING
FRIDAY NIGHT WHICH SHOULD CAUSE SFC TEMPS AND DEWPOINTS TO RISE
ABOVE FREEZING ACROSS MUCH OF THE CWA BY 6Z SAT. THE GFS AND GEM
HAVE BEEN CONVERGING TOWARDS THE ECMWF...BUT CONTINUE TO BE A BIT
COOLER. I WILL BE LEANING A BIT MORE TOWARDS THE ECMWF DURING THIS
FORECAST PERIOD. LOW TEMPERATURES WILL OCCUR DURING THE MID EVENING
HOURS OF FRIDAY...THEN SLOWLY RISE THROUGH THE NIGHT. ISENTROPIC
LIFT AND ASCENT AHEAD OF THE APPROACHING H5 TROUGH WILL CAUSE LIGHT
RAIN TO DEVELOP. IF THERE IS ENOUGH LOW-LEVEL DRY AIR IN PLACE AS
THE RAIN DEVELOPS THEN WET-BULB COOLING MAY ALLOW SURFACE
TEMPERATURES ACROSS THE NORTHERN AND WESTERN COUNTIES TO DROP BELOW
FREEZING. THERE MAY BE SOME LIGHT PERIODS OF FREEZING RAIN FRIDAY
EVENING BEFORE IT CHANCES TO LIGHT RAIN. ROAD SURFACE ARE FAIRLY
WARM...THUS THE ONLY SLICKS SPOTS THAT MAY DEVELOP FRIDAY EVENING
MAY BE ON BRIDGES AND OTHER ELEVATED ROAD SURFACES.
THE RAIN ON SATURDAY MAY BEGIN TO MIX WITH SNOW ACROSS NORTH CENTRAL
KS DURING THE AFTERNOON HOURS AS THE H5 TROUGH LIFTS NORTHEAST
ACROSS CENTRAL KS INTO EASTERN NE. THE NORTHERN COUNTIES MAY SEE A
PERIOD OF LIGHT SNOW SATURDAY NIGHT...THE RAIN WILL MIX WITH SNOW
ACROSS THE REMAINDER OF THE CWA THROUGH THE EVENING HOURS. THERE MAY
BE A BRIEF PERIOD OF LIGHT SNOW ACROSS NORTHEAST AND EAST CENTRAL KS
BEFORE THE PRECIP MOVES EAST OF THE CWA LATE SATURDAY NIGHT INTO
SUNDAY MORNING. ATTM...THE ACCUMULATING SNOW WILL MOST LIKELY
REMAIN WEST AND NORTH OF THE CWA...FROM WEST CENTRAL KS INTO EASTERN
NE WHERE SEVERAL INCHES OF SNOW MAY ACCUMULATE. THE NORTH CENTRAL
COUNTIES MAY SEE AROUND AN INCH OF SNOW ON GRASSY SURFACES SATURDAY
NIGHT. HIGHS ON SATURDAY WILL REACH THE LOWER TO MID 40S SOUTH OF
I-70 WITH MID TO UPPER 30S NORTH OF I-70. OVERNIGHT LOWS ON SATURDAY
WILL SLOWLY DROP INTO THE 20S.
SUNDAY THROUGH TUESDAY...THE MAIN H5 LOW WILL REMAIN CUTOFF ACROSS
THE SOUTHWEST CONUS AS A LONGER WAVE LENGTH H5 TROUGH DEVELOPS
ACROSS THE EASTERN CONUS. NORTHWEST FLOW ALOFT AND A COLD SFC HIGH
PRESSURE WILL KEEP HIGHS IN THE MID 30S AND OVERNIGHT LOWS IN THE
TEENS AND LOWER 20S.
GARGAN
&&
.AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS AIRMASS REMAINS
RELATIVELY DRY. HIGH PRESSURE MOVING OVER TERMINALS TONIGHT WILL
KEEP WINDS LIGHT THEN ON BACKSIDE OF HIGH AFTER 14Z WINDS WILL BE
SOUTH AROUND 11 KTS. SOME STRONGER WINDS WILL MOX DOWN IN THE
AFTERNOON OWING TO GUSTS NEAR 21 KTS AFTER 18Z WED.
53
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
845 AM EST MON NOV 28 2011
.SYNOPSIS...
SLOW MOVING LOW PRESSURE WILL BRING PERIODS OF RAIN FOR THE FIRST
HALF OF THE WEEK. MILD TEMPERATURES EARLY IN THE WEEK WILL COOL
SIGNIFICANTLY BY WEDNESDAY...WITH RESIDUAL RAIN SHOWERS CHANGING
TO SNOW.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONLY CHANGE THIS UPDATE WILL BE TO INCREASE THE CHANCE OF PRECIP
IN THE EXTERME WESTERN PART OF THE CWA NEAR ZZV TO REFLECT THE
CURRENT RADAR TRENDS. REST UNCHANGED.
A LARGE UPPER LEVEL TROUGH WILL CONTINUE TO DIG SOUTH ACROSS THE
MISSISSIPPI VALLEY TODAY. WITH THE NORTHERN BRANCH UPPER LOW
EJECTING NORTHEAST INTO THE CANADIAN MARITIMES...THIS WILL RESULT
IN SPLIT FLOW DEVELOPING ACROSS THE UPPER OHIO VALLEY LATER TODAY.
HENCE...PRECIP COVERAGE WILL BEGIN TO DIMINISH THIS MORNING...WITH
ISOLATED TO SCATTERED SHOWERS REMAINING FOR THIS AFTN INTO THE
EVENING. BY LATER TONIGHT...THE UPPER TROUGH ACROSS THE MS VALLEY
WILL PULL NORTHWARD...BRINGING AN INCREASING COVERAGE OF SHOWERS
BACK INTO THE FCST. AHEAD OF THE UPPER TROUGH...WARM AIR WILL
CONTINUE TO SURGE NORTHWARD...AND WITH PERHAPS SOME CLOUD BREAKS
IN THE AFTN...EXPECT HIGH TEMPERATURES IN THE UPPER 50S TO LOWER
60S...WITH SOME MID 60S POSSIBLE NEAR/SOUTH OF THE MASON DIXON.
WITH WARM AIR REMAINING ACROSS THE AREA TNGT...ALONG WITH
CLOUDS...EXPECT VERY MILD LOW TEMPERATURES IN THE LOWER TO MID
50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE UPPER LOW PRESSURE SYSTEM IS PROGGED TO MIGRATE NORTH INTO
THE REGION TUESDAY INTO TUESDAY NIGHT...EJECTING NORTHEAST
WEDNESDAY. WIDESPREAD SHOWERS WILL PREVAIL FOR MOST OF TUESDAY
WITH A GRADUAL DECREASING TREND TUESDAY NIGHT...AND MAINLY
SCATTERED PRECIP WEDNESDAY. EXPECTED POSITIONING OF OCCLUDING
SURFACE FRONT...FORECAST TRACK OF THE LOW...AND MID LEVEL DRY
PUNCH MAY LIMIT PRECIP TOTALS...BUT WITH AMOUNTS FORECAST IN
THE 1 INCH RANGE...ON TOP OF SUNDAY/MONDAY RAINFALL...WILL
CONTINUE MENTION OF STREAM RISES IN THE HAZARDOUS WEATHER OUTLOOK.
AS THE UPPER LOW MOVES NORTHEAST OF THE AREA...MUCH COLDER AIR
WILL ENTER THE REGION...WITH PRECIP CHANGING OVER TO SNOW FOR MOST
AREAS WEDNESDAY. WITH TEMPERATURES REMAINING ABOVE FREEZING UNTIL
WEDNESDAY NIGHT...AND EXPECTED LIGHT SNOWFALL RATES...DO NOT
EXPECT SIGNIFICANT ACCUMULATION...WITH PERHAPS AN INCH OR SO ON
THE RIDGES AND ALONG THE I-80 CORRIDOR.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD ACROSS THE AREA THURSDAY FOR DRY BUT
CHILLY CONDITIONS. MODELS HAVE BEEN CONSISTENT WITH A WEAK COLD
FRONT CLIPPING THE AREA LATE FRIDAY/FRIDAY NIGHT. WITH LIMITED
MOISTURE...WILL USE LOW END CHANCE POPS. DRY AND CHILLY CONDITIONS
ARE EXPECTED FOR THE WEEKEND.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
PER RECENT SURFACE AND RADAR DATA ALONG WITH HRRR AND NAM MODEL
OUTPUT, EXPECT FRONTAL RAIN BAND, NORTHEAST OF KENTUCKY LOW PRESSURE
CENTER TO REMAIN OVER MUCH OF THE UPPER OHIO VALLEY THROUGH 15Z,
BEFORE PIVOTING NORTHWESTWARD THE REST OF TODAY.
WITH THE RAIN BAND, THERE CAN BE PERIODS OF IFR THROUGH 15Z,
ALTHOUGH MVFR CONDITIONS WILL BE MORE PREVALENT. AS THE RAIN BAND
EXITS NORTHWEST, EXPECT VFR TO BECOME THE PREVALENT FLIGHT CONDITION
THIS AFTERNOON, EXCEPT FOR MAYBE KZZV AND KFKL.
OUTLOOK...MONDAY NIGHT THROUGH FRIDAY....
NORTHEASTWARD MOVING COLD FRONTAL BAND OF RAIN WILL PROVIDE RENEWED
RESTRICTIONS LATE TUESDAY MORNING INTO TUESDAY NIGHT. POST SYSTEM
WRAP AROUND SHOWERS OF RAIN AND SNOW MAY CAUSE ADDITIONAL SHORT
PERIODS OF RESTRICTIONS WEDNESDAY. AFTER VFR UNDER HIGH PRESSURE
THURSDAY, COLD FRONTAL SHOWERS OF RAIN OR SNOW MAY PROVIDE
RESTRICTIONS FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
636 AM EST MON NOV 28 2011
.SYNOPSIS...
SLOW MOVING LOW PRESSURE WILL BRING PERIODS OF RAIN FOR THE FIRST
HALF OF THE WEEK. MILD TEMPERATURES EARLY IN THE WEEK WILL COOL
SIGNIFICANTLY BY WEDNESDAY...WITH RESIDUAL RAIN SHOWERS CHANGING
TO SNOW.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LARGE UPPER LEVEL TROUGH WILL CONTINUE TO DIG SOUTH ACROSS
THE MISSISSIPPI VALLEY TODAY. WITH THE NORTHERN BRANCH UPPER LOW
EJECTING NORTHEAST INTO THE CANADIAN MARITIMES...THIS WILL RESULT
IN SPLIT FLOW DEVELOPING ACROSS THE UPPER OHIO VALLEY LATER TODAY.
HENCE...PRECIP COVERAGE WILL BEGIN TO DIMINISH THIS MORNING...WITH
ISOLATED TO SCATTERED SHOWERS REMAINING FOR THIS AFTN INTO THE
EVENING. BY LATER TONIGHT...THE UPPER TROUGH ACROSS THE MS
VALLEY WILL PULL NORTHWARD...BRINGING AN INCREASING COVERAGE OF
SHOWERS BACK INTO THE FCST. AHEAD OF THE UPPER TROUGH...WARM
AIR WILL CONTINUE TO SURGE NORTHWARD...AND WITH PERHAPS SOME CLOUD
BREAKS IN THE AFTN...EXPECT HIGH TEMPERATURES IN THE UPPER 50S
TO LOWER 60S...WITH SOME MID 60S POSSIBLE NEAR/SOUTH OF THE
MASON DIXON. WITH WARM AIR REMAINING ACROSS THE AREA TNGT...ALONG
WITH CLOUDS...EXPECT VERY MILD LOW TEMPERATURES IN THE LOWER TO
MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE UPPER LOW PRESSURE SYSTEM IS PROGGED TO MIGRATE NORTH INTO
THE REGION TUESDAY INTO TUESDAY NIGHT...EJECTING NORTHEAST
WEDNESDAY. WIDESPREAD SHOWERS WILL PREVAIL FOR MOST OF TUESDAY
WITH A GRADUAL DECREASING TREND TUESDAY NIGHT...AND MAINLY
SCATTERED PRECIP WEDNESDAY. EXPECTED POSITIONING OF OCCLUDING
SURFACE FRONT...FORECAST TRACK OF THE LOW...AND MID LEVEL DRY
PUNCH MAY LIMIT PRECIP TOTALS...BUT WITH AMOUNTS FORECAST IN
THE 1 INCH RANGE...ON TOP OF SUNDAY/MONDAY RAINFALL...WILL
CONTINUE MENTION OF STREAM RISES IN THE HAZARDOUS WEATHER OUTLOOK.
AS THE UPPER LOW MOVES NORTHEAST OF THE AREA...MUCH COLDER AIR
WILL ENTER THE REGION...WITH PRECIP CHANGING OVER TO SNOW FOR MOST
AREAS WEDNESDAY. WITH TEMPERATURES REMAINING ABOVE FREEZING UNTIL
WEDNESDAY NIGHT...AND EXPECTED LIGHT SNOWFALL RATES...DO NOT
EXPECT SIGNIFICANT ACCUMULATION...WITH PERHAPS AN INCH OR SO ON
THE RIDGES AND ALONG THE I-80 CORRIDOR.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD ACROSS THE AREA THURSDAY FOR DRY BUT
CHILLY CONDITIONS. MODELS HAVE BEEN CONSISTENT WITH A WEAK COLD
FRONT CLIPPING THE AREA LATE FRIDAY/FRIDAY NIGHT. WITH LIMITED
MOISTURE...WILL USE LOW END CHANCE POPS. DRY AND CHILLY CONDITIONS
ARE EXPECTED FOR THE WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
PER RECENT SURFACE AND RADAR DATA ALONG WITH HRRR AND NAM MODEL
OUTPUT, EXPECT FRONTAL RAIN BAND, NORTHEAST OF KENTUCKY LOW PRESSURE
CENTER TO REMAIN OVER MUCH OF THE UPPER OHIO VALLEY THROUGH 15Z,
BEFORE PIVOTING NORTHWESTWARD THE REST OF TODAY.
WITH THE RAIN BAND, THERE CAN BE PERIODS OF IFR THROUGH 15Z,
ALTHOUGH MVFR CONDITIONS WILL BE MORE PREVALENT. AS THE RAIN BAND
EXITS NORTHWEST, EXPECT VFR TO BECOME THE PREVALENT FLIGHT CONDITION
THIS AFTERNOON, EXCEPT FOR MAYBE KZZV AND KFKL.
OUTLOOK...MONDAY NIGHT THROUGH FRIDAY....
NORTHEASTWARD MOVING COLD FRONTAL BAND OF RAIN WILL PROVIDE RENEWED
RESTRICTIONS LATE TUESDAY MORNING INTO TUESDAY NIGHT. POST SYSTEM
WRAP AROUND SHOWERS OF RAIN AND SNOW MAY CAUSE ADDITIONAL SHORT
PERIODS OF RESTRICTIONS WEDNESDAY. AFTER VFR UNDER HIGH PRESSURE
THURSDAY, COLD FRONTAL SHOWERS OF RAIN OR SNOW MAY PROVIDE
RESTRICTIONS FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
238 AM EST MON NOV 28 2011
.SYNOPSIS...
SLOW MOVING LOW PRESSURE WILL BRING PERIODS OF RAIN FOR THE FIRST
HALF OF THE WEEK. MILD TEMPERATURES EARLY IN THE WEEK WILL COOL
SIGNIFICANTLY BY WEDNESDAY...WITH RESIDUAL RAIN SHOWERS CHANGING
TO SNOW.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LARGE UPPER LEVEL TROUGH WILL CONTINUE TO DIG SOUTH ACROSS
THE MISSISSIPPI VALLEY TODAY. WITH THE NORTHERN BRANCH UPPER LOW
EJECTING NORTHEAST INTO THE CANADIAN MARITIMES...THIS WILL RESULT
IN SPLIT FLOW DEVELOPING ACROSS THE UPPER OHIO VALLEY LATER TODAY.
HENCE...PRECIP COVERAGE WILL BEGIN TO DIMINISH THIS MORNING...WITH
ISOLATED TO SCATTERED SHOWERS REMAINING FOR THIS AFTN INTO THE
EVENING. BY LATER TONIGHT...THE UPPER TROUGH ACROSS THE MS
VALLEY WILL PULL NORTHWARD...BRINGING AN INCREASING COVERAGE OF
SHOWERS BACK INTO THE FCST. AHEAD OF THE UPPER TROUGH...WARM
AIR WILL CONTINUE TO SURGE NORTHWARD...AND WITH PERHAPS SOME CLOUD
BREAKS IN THE AFTN...EXPECT HIGH TEMPERATURES IN THE UPPER 50S
TO LOWER 60S...WITH SOME MID 60S POSSIBLE NEAR/SOUTH OF THE
MASON DIXON. WITH WARM AIR REMAINING ACROSS THE AREA TNGT...ALONG
WITH CLOUDS...EXPECT VERY MILD LOW TEMPERATURES IN THE LOWER TO
MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE UPPER LOW PRESSURE SYSTEM IS PROGGED TO MIGRATE NORTH INTO
THE REGION TUESDAY INTO TUESDAY NIGHT...EJECTING NORTHEAST
WEDNESDAY. WIDESPREAD SHOWERS WILL PREVAIL FOR MOST OF TUESDAY
WITH A GRADUAL DECREASING TREND TUESDAY NIGHT...AND MAINLY
SCATTERED PRECIP WEDNESDAY. EXPECTED POSITIONING OF OCCLUDING
SURFACE FRONT...FORECAST TRACK OF THE LOW...AND MID LEVEL DRY
PUNCH MAY LIMIT PRECIP TOTALS...BUT WITH AMOUNTS FORECAST IN
THE 1 INCH RANGE...ON TOP OF SUNDAY/MONDAY RAINFALL...WILL
CONTINUE MENTION OF STREAM RISES IN THE HAZARDOUS WEATHER OUTLOOK.
AS THE UPPER LOW MOVES NORTHEAST OF THE AREA...MUCH COLDER AIR
WILL ENTER THE REGION...WITH PRECIP CHANGING OVER TO SNOW FOR MOST
AREAS WEDNESDAY. WITH TEMPERATURES REMAINING ABOVE FREEZING UNTIL
WEDNESDAY NIGHT...AND EXPECTED LIGHT SNOWFALL RATES...DO NOT
EXPECT SIGNIFICANT ACCUMULATION...WITH PERHAPS AN INCH OR SO ON
THE RIDGES AND ALONG THE I-80 CORRIDOR.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD ACROSS THE AREA THURSDAY FOR DRY BUT
CHILLY CONDITIONS. MODELS HAVE BEEN CONSISTENT WITH A WEAK COLD
FRONT CLIPPING THE AREA LATE FRIDAY/FRIDAY NIGHT. WITH LIMITED
MOISTURE...WILL USE LOW END CHANCE POPS. DRY AND CHILLY CONDITIONS
ARE EXPECTED FOR THE WEEKEND.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
PER RECENT SURFACE AND RADAR DATA ALONG WITH HRRR AND NAM MODEL
OUTPUT, EXPECT FRONTAL RAIN BAND, NORTHEAST OF KENTUCKY LOW PRESSURE
CENTER TO REMAIN OVER MUCH OF THE UPPER OHIO VALLEY THROUGH 15Z,
BEFORE PIVOTING NORTHWESTWARD THE REST OF TODAY. MVFR CONDITIONS
WILL BE PREVALENT WITH THE RAIN BAND, BUT THERE CAN BE PERIODS OF
IFR 09Z-14Z. AS RAIN BAND EXITS NORTHWEST, EXPECT VFR TO BECOME
PREVALENT THIS AFTERNOON, EXCEPT FOR MAYBE KZZV AND KFKL.
OUTLOOK...MONDAY NIGHT THROUGH FRIDAY....
NORTHEASTWARD MOVING COLD FRONTAL BAND OF RAIN WILL PROVIDE RENEWED
RESTRICTIONS LATE TUESDAY MORNING INTO TUESDAY NIGHT. POST SYSTEM
WRAP AROUND SHOWERS OF RAIN AND SNOW MAY CAUSE ADDITIONAL SHORT
PERIODS OF RESTRICTIONS WEDNESDAY. AFTER VFR UNDER HIGH PRESSURE
THURSDAY, COLD FRONTAL SHOWERS OF RAIN OR SNOW MAY PROVIDE
RESTRICTIONS FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
101 AM EST MON NOV 28 2011
.SYNOPSIS...
A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING PERIODS OF RAIN FOR THE
FIRST HALF OF THE WEEK. MILD TEMPERATURES EARLY IN THE WEEK WILL
COOL SIGNIFICANTLY BY WEDNESDAY AND CHANGE RESIDUAL RAIN SHOWERS TO
SNOW.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WITH A TROUGH DIGGING ACROSS THE MISSISSIPPI VALLEY...RAIN WILL
CONTINUE THROUGH THE OVERNIGHT...WITH CATEGORICAL COVERAGE FROM
A DUJ/PIT/MGW LINE WESTWARD. FURTHER EAST...WILL USE CHANCE POPS
TO LBE...WITH LITTLE/NO PRECIP FOR THE WV/MD RIDGES. NEAR
STEADY TEMPERATURES IN THE UPPER 40S TO LOWER 50 WILL PREVAIL.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
PERIODIC SHOWERS CAN BE EXPECTED INTO MID WEEK AS THE MATURING LOW
DIGS NEWD. RAINFALL TOTALS THROUGH TUESDAY NIGHT WERE CONSERVATIVELY
FORECAST AT APPROXIMATELY AN INCH FOR MOST AREAS...BUT INCREASED
TO NEAR 2 INCHES ALONG THE INTERSTATE 77 CORRIDOR IN RESPONSE TO
EXPECTED POSITIONING OF OCCLUDING FRONT/FORECAST TRACK OF THE LOW.
MID LEVEL DRY PUNCH AND SHIFTING FRONTOGENESIS SLOT SHOULD LIMIT
TOTALS...BUT MENTION OF STREAM RISES WAS NEVERTHELESS INCLUDED IN
THE HAZARDOUS WEATHER OUTLOOK FOR THIS PERIOD.
SHORT TERM TEMPERATURES WILL REMAIN MILD UNTIL THE SYSTEMS COLD
FRONT SWEEPS THE REGION ON TUESDAY NIGHT AND CHANGES RESIDUAL PCPN
TO SNOW SHOWERS FOR WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BY WEDNESDAY EVENING NORTHERLY FLOW BEHIND EXITING STORM IN NEW
ENGLAND MAY KEEP A FEW SHOWERS/FLURRIES OVER REGION EARLY. HIGH
PRESSURE WILL BUILD NORTHEAST TO WV BY THURSDAY MORNING BRINGING
DRIER AIR AND SUNSHINE. MODELS CONSISTENT WITH COLD MOVING
SOUTHEAST FROM GREAT LAKES ON FRIDAY WITH LIMITED MOISTURE. CHANCE
OF SHOWERS FROM MID DAY FRIDAY ON. BY SATURDAY BROAD WESTERLY FLOW
WILL BRING COLDER TEMPERATURES WITH LOWS IN THE 20S AND HIGHS IN THE
30S AND LITTLE THREAT OF PRECIPITATION FOR THE WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
PER RECENT SURFACE AND RADAR DATA COUPLED WITH HRRR AND NAM MODEL
OUTPUT, EXPECT FRONTAL RAIN BAND NORTHEAST OF KENTUCKY LOW
PRESSURE CENTER TO MOVE INTO EASTERN PARTS OF THE UPPER OHIO
VALLEY THROUGH 15Z, BEFORE PIVOTING NORTHWESTWARD THE REST OF
TODAY. EXPECT MVFR CONDITIONS TO BE PREVALENT WITH THE RAIN BAND,
BUT THERE CAN BE PERIODS OF IFR 09Z-14Z. AS RAIN BAND EXITS
NORTHWEST, EXPECT VFR TO BECOME PREVALENT THIS AFTERNOON, EXCEPT
FOR MAYBE KZZV AND KFKL.
OUTLOOK...MONDAY NIGHT THROUGH FRIDAY....
NORTHEASTWARD MOVING COLD FRONTAL BAND OF RAIN WILL PROVIDE
RESTRICTIONS LATE TUESDAY MORNING INTO TUESDAY NIGHT. POST SYSTEM
WRAP AROUND SHOWERS OF RAIN AND SNOW MAY CAUSE ADDITIONAL SHORT
PERIODS OF RESTRICTIONS WEDNESDAY. AFTER VFR UNDER HIGH PRESSURE
THURSDAY, COLD FRONTAL SHOWERS OF RAIN OR SNOW MAY PROVIDE
RESTRICTIONS FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
420 PM EST MON NOV 28 2011
.SYNOPSIS...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW PROGRESSIVE FLOW ACROSS SRN
CANADA...FEATURING A WEAK RIDGE OVER SW CANADA...A SHORTWAVE TROF
OVER MANITOBA AND ANOTHER SHORTWAVE OVER QUEBEC. A CUTOFF LOW IS
OVER THE LWR MISSISSIPPI VALLEY. INCREASING SW FLOW AHEAD OF THE
MANITOBA SHORTWAVE HAS SCOURED OUT LOW CLOUDS ACROSS MOST OF THE
FCST AREA WITH DOWNSLOPING NEAR LAKE SUPERIOR AIDING THE CLEARING
TREND. AS OF 2030Z...LAST OF THE LOW CLOUDS ARE DOWNWIND OF LAKE
MICHIGAN...E OF KESC-GRAND MARAIS LINE. APPROACHING COLD FRONT
ASSOCIATED WITH MANITOBA SHORTWAVE IS NOT ACCOMPANIED BY ANY PCPN S
OF THE INTERNATIONAL BORDER AS AIRMASS IS DRY PER 12Z SOUNDINGS.
&&
.SHORT TERM /TONIGHT AND TUE/...
SHORT TERM WILL BE GENERALLY QUIET AS OVERALL DRY AIRMASS LIMITS ANY
PCPN POTENTIAL DESPITE PASSAGE OF SHORTWAVE. COLD FRONT ASSOCIATED
WITH SHORTWAVE MOVING ACROSS ONTARIO TONIGHT WILL BRING A WIND SHIFT
AND USHER IN A PERIOD OF DECENT CAA (850MB TEMPS FALL FROM 0 TO 2C
THIS EVENING TO -6 TO -8C BY 12Z TUE). SHOULD BEGIN TO SEE AN
INCREASE IN LAKE EFFECT CLOUDS OVERNIGHT AS OVERWATER INSTABILITY
IMPROVES. OTHERWISE...NO PCPN IS EXPECTED AS AIRMASS IS DRY.
ON TUE...BRISK N WINDS AND MORE THAN ADEQUATE OVERWATER INSTABILITY
WILL LEAD TO QUITE A BIT OF STRATOCU OFF LAKE SUPERIOR. ALTHOUGH
850MB TEMPS ARE MARGINALLY COLD TO SUPPORT FLURRIES/-SHSN OFF THE
LAKE...TEMPS IN THE SHALLOW MOIST LAYER ARE JUST ABOVE -10C. IF
ANYTHING...THERE MIGHT BE SOME -FZDZ...BUT SUBCLOUD LAYER ON FCST
SOUNDINGS LOOKS TOO DRY TO SUPPORT THAT. THE LACK OF LOW CLOUDS WELL
UPSTREAM SUPPORTS MODEL FCST OF SOMEWHAT DRIER LOWER BOUNDARY LAYER.
IF THERE SOMEHOW IS A LITTLE PCPN TUE...IT WOULD PROBABLY BE OVER
NCNTRL UPPER MI (ERN BARAGA/MARQUETTE/WRN ALGER) DUE TO
PRECONDITIONING/STREAMLINE OFF LAKE NIPIGON INTO THAT AREA. IT WILL
BE A SEASONABLY CHILLY DAY WITH HIGHS IN THE UPPER 20S TO MID 30S.
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
TUESDAY NIGHT THROUGH WEDNESDAY EVENING...
WITH THE CONTINUED NORTHEASTWARD EJECTION OF
THE CUT OFF LOW OVER THE OHIO VALLEY AT 00Z WEDNESDAY TO THE LOWER
GREAT LAKES BY DAYBREAK WEDNESDAY...AND ACROSS QUEBEC THEREAFTER.
THE RESULT FOR THE UPPER GREAT LAKES WILL BE A 500MB RIDGE
OVERHEAD...AND A RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE AREA
FROM TX. SENSIBLE WEATHER WISE...EXPECT DRY CONDITIONS WITH WARMING
ALOFT FROM A CWA AVERAGE -4 TO -1C AT 850MB DURING THE PERIOD.
THURSDAY MORNING THROUGH FRIDAY MORNING...
THE NEXT FEATURE OF INTEREST WILL BE SLIDING ACROSS EASTERN MT
WEDNESDAY MORNING...AND BETTER ORGANIZING FROM ND TO EASTERN CO BY
18Z WEDNESDAY. THE FEATURE WILL THEN WEAKEN AS IT SETS UP FROM UPPER
MI THROUGH TX BY 18Z THURSDAY. WITH THE ASSISTANCE OF SOME MID LEVEL
SUPPORT ON THE NORTHERN EDGE OF THIS FEATURE /500MB TROUGH EXTENDING
SW FROM THE NORTHERN PORTIONS OF HUDSON BAY/ LIGHT PRECIPITATION
WILL BE POSSIBLE...MAINLY BEHIND THE SFC LOW. NORTHERLY FLOW AND
850MB TEMPS OF -7 TO -9C BY 18Z THURSDAY SHOULD BRING ABOUT LIGHT
SNOW SHOWERS. INDICATIONS CONTINUE TO POINT AT 1 TO 3 INCHES OF SNOW
THURSDAY ACROSS THE KEWEENAW PENINSULA...WITH VALUES REMAINING BELOW
ADVISORY HEADLINE CRITERIA AT THIS TIME. COOLER NW FLOW WILL THEN
DOMINATE THURSDAY NIGHT WITH 850MB TEMPS BOTTOMING OUT AROUND -13C
BY 12Z FRIDAY...WHILE THE 500MB AXIS AND SFC FRONT EXIT TO OUR
EAST...LIMITING SIGNIFICANT SNOWFALL ACCUMULATIONS.
FRIDAY AFTERNOON AND EVENING...
WAA WILL QUICKLY TAKE HOLD FRIDAY AFTERNOON THROUGH THE EVENING
HOURS WITH 850MB TEMPS REBOUNDING TO AROUND -1 TO -4C DEPENDING ON
WHAT MODEL YOU BELIEVE...AND A WEAK RIDGE SLIDING ACROSS ALOFT.
EITHER WAY IT SHOULD BE DRY WITH SW WINDS...WITH THE LAST OF THE
LAKE EFFECT/LAKE ENHANCED PRECIP ENDING AT 12Z FRIDAY ON MAINLY
WESTERLY WINDS.
BEYOND FRIDAY EVENING THE FORECAST BEGINS TO BECOME A LITTLE LESS
PREDICTABLE. A 500MB TROUGH SET UP FROM N CENTRAL CANADA THROUGH MT
AT 18Z FRIDAY WILL ATTEMPT TO PUSH A SOUTHWESTERN U.S. CUT OFF LOW
INTO THE MAIN FLOW OVER THE WEEKEND...WITH THE ELONGATED TROUGH
SLIDING OVER THE UPPER GREAT LAKES SOMETIME BETWEEN SATURDAY MORNING
AND SUNDAY AFTERNOON...WITH AN ADDITIONAL WAVE ALMOST RIGHT BEHIND
THE PRIMARY WAVE FOR SUNDAY AFTERNOON OR MONDAY AFTERNOON.
YES...THERE IS NEARLY A 24 HOUR DIFFERENCE BETWEEN THE 28/00Z RUN OF
THE ECMWF AND THE 28/00Z AND 06Z RUNS OF THE GFS. THE 12Z RUNS OF
THE GFS AND ECMWF HAVE COME INTO A LITTLE BETTER AGREEMENT ONCE
AGAIN...AND WE WILL HAVE TO WAIT AND SEE IF THIS TREND CONTINUES.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
LOW CLOUDS/MVFR CIGS HAVE BEEN BREAKING UP UNDER STRENGTHENING SW
FLOW. LOW CLOUDS HAVE CLEARED KIWD/KCMX...AND KSAW SHOULD SEE LOW
CLOUDS SCATTER OUT IN THE NEXT HR OR TWO. VFR CONDITIONS WILL THEN
PREVAIL THRU THE AFTN HRS. A COLD FRONT WILL SHIFT ACROSS THE AREA
TONIGHT. INITIALLY...AIRMASS WILL BE TOO WARM FOR LAKE EFFECT
CLOUDS...BUT WILL NEED TO WATCH FOR A BRIEF PERIOD OF MVFR CIGS JUST
BEHIND FRONT THIS EVENING. SATELLITE IMAGERY/SFC OBS SHOW A NARROW
POST-FRONTAL BAND OF MVFR CIGS...BUT THERE IS UNCERTAINTY WHETHER
THE SRN END OF THE STRATOCU DECK WILL SLIP FAR ENOUGH S TO AFFECT
KCMX/KSAW. AS AIRMASS BECOMES COLDER AND OVERWATER INSTABILITY
INCREASES...EXPECT STRATOCU/MVFR CIGS TO DEVELOP OFF LAKE SUPERIOR
AND AFFECT KIWD/KCMX/KSAW TUE MORNING.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
TYPICAL CHANGEABLE LATE FALL PATTERN EXPECTED THIS WEEK. COLD FRONT
WILL PASS ACROSS THE AREA TONIGHT. MAY SEE A FEW GALE FORCE GUSTS
BTWN ISLE ROYALE AND THE KEWEENAW LATE THIS AFTN IN THE SW FLOW
AHEAD OF THE FRONT. BEHIND THE FRONT IN DECENT CAA REGIME...THERE
MAY BE SOME NORTHERLY GALE FORCE GUSTS FROM NCNTRL TO SCNTRL LAKE
SUPERIOR OVERNIGHT/EARLY TUE AS OVERWATER INSTABILITY INCREASES. AT
THIS TIME...IT APPEARS GALE GUSTS SHOULDN`T BE WIDESRPEAD OR
PERSISTENT ENOUGH TO WARRANT A GALE WARNING. WINDS WILL SLOWLY
DIMINISH FROM W TO E TUE AFTN/NIGHT AS HIGH PRES RIDGE MOVES CLOSER
TO THE AREA. LIGHTER WINDS UNDER 20KT WILL BE THE RULE WED
AFTN/NIGHT UNDER WEAK PRES GRADIENT ASSOCIATED SFC TROF SETTLING SE
INTO THE UPPER LAKES. N TO NW WINDS WILL INCREASE INTO THE 15-25KT
RANGE THU/THU NIGHT AS THE TROF SLIPS SE OF THE AREA. AFTER A BRIEF
PERIOD OF LIGHTER WINDS LATE THU NIGHT/FRI MORNING...WINDS WILL
AGAIN BE ON THE INCREASE LATER FRI INTO SAT AHEAD OF THE NEXT LOW
PRES TROF APPROACHING FROM THE NW. MAY SEE GALES IN THE SW FLOW
AHEAD OF THE TROF.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
GALE WARNING FROM 7 AM TO 7 PM EST TUESDAY FOR LMZ221-250.
&&
$$
SYNOPSIS...ROLFSON
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1246 PM EST MON NOV 28 2011
.SYNOPSIS.../ISSUED AT 1031 AM/
PATCHES OF LIGHT LAKE EFFECT SNOW WILL EVENTUALLY TAPER OFF BY
LATE TODAY. HIGH PRESSURE MAKES A BRIEF APPEARANCE TODAY. SKIES
WILL REMAIN MOSTLY CLOUDY. MORE PRECIPITATION IS IN STORE FOR
PARTS OF THE NORTHERN LOWER PENINSULA TUESDAY INTO TUESDAY
NIGHT...MAINLY FOR AREAS SOUTHEAST OF GAYLORD. EASTERN UPPER WILL
PROBABLY STAY DRY THROUGH THIS PERIOD.
LOCKER/HALBLAUB
&&
.SHORT TERM.../ISSUED AT 1031 AM/...THIS AFTERNOON
...MOSTLY CLOUDY AND CHILLY WITH CONTINUING POTENTIAL FOR PATCHES
OF LIGHT SNOW NEAR THE COASTS THRU AFTN...
UPPER-LEVEL FLOW IS HIGHLY AMPLIFIED OVER N AMERICA...BUT
PROGRESSIVE OVER CANADA AND THE NRN USA. SHRTWV RIDGING IS BUILDING
OVER THE GTLKS IN ADVANCE OF THE NEXT TROF CURRENTLY MOVING THRU
MANITOBA-MONTANA. THE SRN USA FLOW IS MORE BLOCKY AND THE TAIL END
OF AN ANTICYCLONIC WAVE-BREAKING EVENT HAS RESULTED IN A CLOSED LOW
OVER THE TN VALLEY IN THE LAST 24 HRS.
AT THE SFC...YESTERDAY`S COLD FRONT /THAT HAS ESTABLISHED MUCH MORE
SEASONABLE TEMPS/ WAS ALONG THE APPALACHIANS WITH A SFC LOW OVER NRN
GA. HIGH PRES EXTENDED FROM OK TO THE GTLKS. THE NEXT INACTIVE COLD
FRONT WAS MOVING INTO THE NRN PLAINS.
CLOUDS: FOG/REFLECTIVITY PRODUCT OVERLAID WITH 925 MB ANALYSIS SHOWS
THAT MVFR STRATUS IS ASSOCIATED WITH THE LOW-LEVEL THERMAL TROF/COLD
POOL. EROSION OF BACK EDGE IS OCCURRING WITH WAA. INTERESTING TO
NOTE THAT THIS EDGE HAS ONLY PROGRESSED FROM WRN MN BORDER TO THE MS
RIVER IN THE LAST 24 HRS.
INITIAL VIS CHANNEL IMAGERY SHOWS BREAKS AND THIN SPOTS. THESE AND
ANY OTHER BREAKS THAT DEVELOP WILL FILL BACK-IN WITH THERMAL TROF
OVERHEAD. SO MAINTAINED A M/CLOUDY FCST FOR THE REST OF THE DAY AND
INCREASED SKYCOVER AFTER 15Z. THE ERN U.P. COULD TURN P/CLOUDY LATE
BUT IT WILL PROBABLY OCCUR JUST BEFORE SUNSET.
INTERESTING CLOUD MICROPHYSICS. STRATUS IS YIELDING PATCHES OF FINE
SNOW GRAINS. THE COLDEST TEMP /AT THE BASE OF THE INVERSION/ IS -7C.
UNSURE HOW FAR TO EXTEND THIS THRU THE DAY. CONDITIONS APPEAR
FAVORABLE FOR IT TO CONTINUE AND 3KM HRRR IS THE ONLY MODEL SHOWING
IT. SO EXPANDED THE THREAT THRU 21Z...MAINLY FOR IMMEDIATE LAKESHORE
COUNTIES BUT THERE COULD BE FLURRY FURTHER INLAND.
TEMPS: THEY`RE REALLY GOING NOWHERE...HOLDING STEADY. THEY`RE NOT
FOLLOWING THE FCST TEMP CURVE DUE TO CLOUD COVER. SO 3-5F WERE
TRIMMED OFF AFTN HIGHS FROM 4 AM APX FCST.
HALBLAUB
&&
.LONG TERM.../ISSUED AT 445 AM/...TONIGHT AND BEYOND
TONIGHT...THE HIGH PRESSURE GOES VIRTUALLY NO WHERE...REMAINING
OVER NRN LOWER...WHILE THE LOW PRESSURE FROM TENNESSEE AND THE
COLD FRONT OUT TO OUR WEST BEGIN TO CONVERGE ON THE GREAT LAKES.
THE SW WIND PICKS UP A BIT ACROSS NW LOWER AND EASTERN UPPER WITH
ADDITIONAL 925MB WARMING...WHICH SHOULD EAT AWAY AT THE
STRATOCU. HOWEVER...INCREASING HIGH CLOUDS FROM BOTH FEATURES
WILL RESULT IN INCREASING CLOUDINESS FOR WHEREVER IT DOES START OF
ON THE CLEARER SIDE OF THINGS. MODEL CONSENSUS SUGGESTS THAT A
DEEP ATLANTIC MOISTURE FEED INTO THE NORTHWARD PROGRESSING LOW
PRESSURE WILL GET WRAPPED AROUND INTO A TROWEL WHICH LIFTS NORTH
OF THE OHIO RIVER VALLEY NEAR DTX BY DAYBREAK. MEANWHILE...NEAR
THE SAGINAW BAY REGION DEFORMATION ZONE AND FGEN ALOFT SNEAKS IN
OVER THE FAR SE CWA FOR SOME MODEL SUGGESTED LIGHT RAIN
DEVELOPMENT. HOWEVER...ANTECEDENT EXTREMELY DRY AIR MASS WILL BE
DIFFICULT TO MOISTEN...ESPECIALLY WHEN CONSIDERING STRENGTHENING
FGEN AND SHARP CUT OFF TO THE NRN EDGE OF THE RAIN SHIELD. MODEL
SOUNDINGS DO NOT SUPPORT ANY PRECIPITATION...AND LOWERED THE
CHANCE FOR SEEING PRECIP...BUT DID LEAVE A SMALL CHANCE RIGHT
NEAR THE SAG BAY. LOW TEMPS WILL BE IN THE LOW 30S.
TUESDAY THROUGH WEDNESDAY...LOW PRESSURE WILL LIFT THROUGH THE
EASTERN GREAT LAKES AND DEEPEN WHILE PARENT UPPER CUT OFF LOW
WILL TRY AND PHASE TO SOME DEGREE WITH NRN STREAM ENERGY. UPSTREAM
COLD FRONT DROPS IN ACROSS NRN MICHIGAN AND MESHES WITH THE LOW
PRESSURE RESULTING IN STRENGTHENING NORTHERLY WINDS AND DRY
ADVECTION OUT OF EASTERN UPPER. MEANWHILE THE DEFORMATION/FGEN AND
TROWAL LIFTS UP INTO NE LOWER. EXACTLY HOW FAR NORTH THE SHARP
CUTOFF TO THE NRN EDGE OF THE PRECIPITATION MAKES IT...IS STILL A
BIT UNCLEAR. THAT SAID...FEEL THAT THE NW HALF OF THE CWA IS
LIKELY TO SEE NO PRECIPITATION...WHILE A GOOD CHUNK OF NE LOWER IS
GONNA GET A LITTLE DAMP. MODEL SUGGESTIONS OF WARM WEDGE OF AIR
ALOFT (TROWAL) MOVING IN OVER SFC TEMPS LOWERING TO 32F OR LOWER
TUESDAY NIGHT IN PARTS OF THE PRECIP SHIELD ARE MOST LIKELY NOT
GONNA HAPPEN. TEMPERATURES OVER THIS AREA WILL LIKELY REMAIN AT OR
JUST ABOVE FREEZING...AND ANY CHANCE OF NEW NAM SOUNDINGS
SUGGESTING SOME FREEZING RAIN ARE SMALL. HAVE CONTINUED THE THEME
OF RAIN AND SNOW...BUT LOWERED THE POTENTIAL SNOW AMOUNTS DUE TO A
WARMER SCENARIO/HIGHER SNOW/WATER RATIOS. MAYBE AN INCH AROUND THE
SAGINAW BAY. DUE TO THE UNCERTAINTY AND MARGINAL THERMAL REGIMES
WILL CONTINUE TO MENTION THE POTENTIAL FOR ACCUMULATING SNOW IN
THE HWOAPX. THE WEATHER IMPROVES INTO WEDNESDAY AS THE LOW
PRESSURE WORKS ITS WAY OUT OF THE EASTERN GREAT LAKES...TAKING THE
DEEPER MOISTURE AND FORCING OUT OF NE LOWER. OUTSIDE OF NE
LOWER...THE REMAINDER OF THE CWA WILL LIKELY BE UNDER AT LEAST
HIGH LEVEL CLOUDS. SKIES WILL BE CLEAREST ACROSS FAR WESTERN
CHIP/MACK COUNTIES. HIGHS WILL BE IN THE UPPER 30S TO AROUND 40
DEGREES AGAIN.
THURSDAY ONWARD...ONE NORTHERN STREAM SHORTWAVE STILL EXPECTED
THURS-THURS NIGHT FOR POSSIBLE CHANCE AT SNOW...WHILE A BETTER
SHOT MAY DEVELOP OVER THE WEEKEND. NOT MANY CHANGES IN THIS TIME
PERIOD.
SMD
&&
.MARINE.../ISSUED AT 1131 AM/
HIGH PRES IS OVER THE LAKES TODAY...RESULTING IN LIGHT WINDS AND
LOW SEAS. HALBLAUB
THE MAIN MARINE ISSUE WILL BE A LOW PRESSURE SYSTEM LIFTING
THROUGH THE EASTERN GREAT LAKES TUESDAY THROUGH WEDNESDAY. A TIGHT
PRESSURE GRADIENT IS ANTICIPATED WITH DEFINITE SMALL CRAFT
ADVISORIES ACROSS ALL NEARSHORES. THE GALE POTENTIAL IS BECOMING
MORE CERTAIN FOR PORTIONS OF THE NEARSHORES OF LAKE MICHIGAN AND
HURON...MAINLY SURROUNDING NORTHERN LOWER MICHIGAN.
SMD
&&
.AVIATION.../ISSUED AT 1246 PM/...VALID FOR 18Z TAFS
...STRONG CROSS WINDS BEGIN TUE AT ALL TERMINALS EXCEPT ALPENA...
HIGH PRES IS OVERHEAD TODAY. COLD FROPA OCCURS TNGT WITH STRONG LOW
PRES APPROACHING THE GTLKS FROM THE S TUE-WED.
REST OF THIS AFTN: 2000-3000 FT MVFR CIGS WILL CONTINUE WITH LGT
WINDS. COULD SEE A FEW BINOVC. WITH MODEL GUIDANCE NOT HANDLING LOW
CLOUDS WELL...THIS FCST IS MAINLY PERSISTENCE. SO WE LOOK TO
ANYTHING THAT MIGHT CHANGE THE PRESENT SITUATION. ATTM IT DOES NOT
APPEAR ANYTHING WILL CHANGE UNTIL TNGT.
TNGT: COLD FROPA WILL OCCUR 05-06Z PLN TVC MBL AND 08-09Z APN. THIS
WILL ADVECT IN DRIER LOW-LEVEL AIR AND BELIEVE THIS WILL SCOUR OUT
MVFR CIGS. WINDS WILL BE LGT UNTIL FROPA THEN BECOME NNE 3-10 KTS.
LOSS/DIMINISHING OF LOW STRATUS WILL REVEAL VFR CIRRUS CIGS.
PERIOD OF VFR WILL BE PROBABLY BE SHORT-LIVED AT APN. NE WINDS WILL
RESULT IN MVFR LAKE CLOUDS MOVING INTO APN BEFORE SUNRISE.
TUE THRU 18Z: SIGNIFICANT CROSS WINDS WILL BE A PROBLEM AT MBL TVC
PLN. N-NE WINDS WILL INCREASE AND GUST UP TO 30 KTS WITH THE HIGHEST
PROBABILITY OF G30 OCCURRING AT MBL. ISOLATED HIGHER GUSTS ARE
POSSIBLE AFTER 18Z.
MVFR LAKE CLOUDS CONTINUE AT APN AND VFR THICKENING MID-HIGH LEVEL
CIGS. THERE COULD BE A FEW LAKE CLOUDS AT TVC AND MBL...BUT NOT
EXPECTED TO BECOME BKN.
HALBLAUB
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON FOR
LHZ347>349.
LM...GALE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON FOR
LMZ323-342-344>346.
LS...NONE.
&&
$$
WFO APX
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1227 PM EST MON NOV 28 2011
UPDATED AVIATION DISCUSSION FOR THE 18Z TAFS
.SYNOPSIS /ISSUED AT 514 AM/...
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGING FROM
THE SW CONUS THROUGH THE UPPER MS VALLEY TO HUDSON BAY AND A CUTOFF
LOW OVER THE LOWER MS VALLEY. MAINLY ZONAL NRN STREAM FLOW
PREVAILED FROM THE EPAC THROUGH SRN CANADA AND THE NRN PLAINS. A
SHORTWAVE TROUGH EXTENDED FROM SRN SASK INTO NW MT WAS MOVING
STEADILY TO THE EAST. AT THE SFC...SRLY WINDS WERE INCREASING OVER
MN AND THE ERN DAKOTAS BTWN A TROUGH FROM MANITOBA TO THE WRN PLAINS
AND A RIDGE INTO THE WRN GREAT LAKES. IR 11-3.9 LOOP SHOWED THAT THE
BACK EDGE OF PERSISTENT LOW CLOUDS OVER UPPER MI...WI AND ERN MN WAS
ONLY MAKING SLOW OR LITTLE PROGRESS TO THE EAST. KINL/KMPX/KGRB
SOUNDINGS SHOWED MOIST LAYER TRAPPED BELOW A STRONG 900-850 MB
INVERSION. RADAR INDICATED THAT THE LIGHT LAKE EFFECT SNOW SHOWERS
OR FLURRIES OVER ERN LAKE SUPERIOR HAD DIMINISHED TO NO MORE THAN A
FEW FLURRIES FROM MUNISING EASTWARD.
&&
.DISCUSSION... ISSUED AT 514 AM EST
TODAY...NAM/RUC 925-900 MB RH PROGS SUGGEST THAT THE LOW CLOUDS
SHOULD DISSIPATE AND/OR DEPART TO THE EAST THIS MORNING AS LOW LEVEL
SW WINDS INCREASE. THIS WOULD LEAVE PARTLY TO MOSTLY SUNNY SKIES
THIS AFTERNOON AS MID/HIGH CLOUDS SUPPORTED BY WAA AHEAD OF THE
PLAINS TROUGH SPREAD INTO THE AREA. HOWEVER...SINCE THE MODELS HAVE
RECENTLY BEEN TOO EAGER TO REMOVE THE LOWER CLOUDS...EXPECT A DELAY
IN CLEARING MAY EXTEND INTO THE AFTERNOON. THIS SHOULD LIMIT MAX
TEMPS TO MAINLY THE MID 30S...WITH SOME UPPER 30S TO AROUND 40
READINGS AT LOCATIONS FAVORED BY SW DOWNSLOPE FLOW.
TONIGHT...THE SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO WILL DRAG
A COLD FRONT/TROUGH THROUGH THE AREA. THE WEAK TO MODERATE QVECTOR
FORCING ACCOMPANYING THE TROUGH WILL REMAIN MAINLY NORTH OF THE CWA.
WITH LITTLE MOISTURE AVAILABLE...NO MEASURABLE PCPN IS EXPECTED.
KEPT TEMPS NEAR THE HIGHER END OF GUIDANCE AS CLOUDS WILL AGAIN KEEP
TEMPS FROM FALLING OFF TOO MUCH.
TUESDAY...STIFF NRLY WINDS WITH INFLUX OF LAKE MOISTURE AND
UPSLOPE FLOW WILL SUPPORT PERSISTENT LOWER CLOUDS OVER THE AREA.
ALTHOUGH THE SHALLOW LOWER CLOUD LAYER EXTENDING ONLY UP TO 900-850
TEMPS AROUND -6C MAY SUGGEST POTENTIAL FOR -FZDZ...A RELATIVELY DRY
SUB CLOUD LAYER WOULD NOT BE FAVORABLE.
TUE NIGHT INTO WED...WITH THE MID LEVEL AND SFC RIDGE BUILDING INTO
THE AREA...ALONG WITH DRY ADVECTION...CLEARING SHOULD TAKE OVER BY
LATE TUE AND LINGER INTO WED MORNING. SO...TEMPS NEAR CONSENSUS
GUIDANCE APPEARED REASONABLE WITH READINGS INTO THE UPPER TEENS
INLAND WEST AND MID 20S NEAR THE LAKES AND OVER THE ERN CWA. TEMPS
SHOULD REBOUND TO THE MID AND UPPER 30S WED.
WED NIGHT INTO THU...THE GFS/ECMWF/GEM SUGGEST THAT ANOTHER
SHORTWAVE AND FRONT MOVING THROUGH THE AREA ACCOMPANIED BY AT LEAST
MODERATE MID LEVEL FGEN WILL SUPPORT AN AREA OF LIGHT SNOW OVER THE
REGION. DIFFERENCES REMAIN WITH THE PLACEMENT/INTENSITY OF THE PCPN.
FOR NOW...ONLY CHANCE POPS WERE INCLUDED.
FRI...CAA IN THE WAKE OF THE FRONT DROPPING 850 MB TEMPS INTO THE
-12C TO -14C...PER GFS/ECMWF RANGE SHOULD GENERATE LES INTO EARLY
FRI FOR NW FLOW SNOWBELTS. ANY LES WOULD BE SHORTLIVED AS THE
PROGRESSIVE PATTERN WOULD LIKELY BRING WAA QUICKLY BACK INTO THE
AREA BY THE END OF THE WEEK.
INTO THE WEEKEND...
MODELS SHOW GENERAL TROUGHING PATTERN INTO THE CNTRL CONUS.
HOWEVER...SIGNIFICANT DIFFERENCES EMERGE REGARDING WHETHER THE DRIER
NRN STREAM WILL DOMINATE WITH MAINLY LES CHANCES (GFS) OR POSSIBLE
PHASING WITH SRN STREAM COULD BRING MORE SUBSTANTIAL MOISTURE/SNOW
INTO THE AREA (ECMWF). FOR NOW...THE FCST LEANS TOWARD THE GFS
SCENARIO WITH TEMPS FALLING INTO THE UPPER 20S AND LOWER 30S BY SUN
WITH LES CHANCES...TYPICAL FOR EARLY WINTER.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
LOW CLOUDS/MVFR CIGS HAVE BEEN BREAKING UP UNDER STRENGTHENING SW
FLOW. LOW CLOUDS HAVE CLEARED KIWD/KCMX...AND KSAW SHOULD SEE LOW
CLOUDS SCATTER OUT IN THE NEXT HR OR TWO. VFR CONDITIONS WILL THEN
PREVAIL THRU THE AFTN HRS. A COLD FRONT WILL SHIFT ACROSS THE AREA
TONIGHT. INITIALLY...AIRMASS WILL BE TOO WARM FOR LAKE EFFECT
CLOUDS...BUT WILL NEED TO WATCH FOR A BRIEF PERIOD OF MVFR CIGS JUST
BEHIND FRONT THIS EVENING. SATELLITE IMAGERY/SFC OBS SHOW A NARROW
POST-FRONTAL BAND OF MVFR CIGS...BUT THERE IS UNCERTAINTY WHETHER
THE SRN END OF THE STRATOCU DECK WILL SLIP FAR ENOUGH S TO AFFECT
KCMX/KSAW. AS AIRMASS BECOMES COLDER AND OVERWATER INSTABILITY
INCREASES...EXPECT STRATOCU/MVFR CIGS TO DEVELOP OFF LAKE SUPERIOR
AND AFFECT KIWD/KCMX/KSAW TUE MORNING.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT INCREASNIG SW WINDS UP TO 30 KTS TODAY UNDER SHARPENING PRES
GRADIENT BETWEEN DEPARTING SFC HI OVER THE CENTRAL GREAT LAKES AND
AN APPROACHING COLD FRONT. THERE MAY EVEN BE A FEW GALE FORCE GUSTS
BETWEEN ISLE ROYALE AND THE KEWEENAW WHERE TERRAIN INFLUENCES WILL
ACCENTUATE THIS FLOW. AFTER THIS FRONT PASSES LAKE SUPERIOR
TONIGHT...THERE WILL BE WSHFT TO THE N. DEPENDING ON HOW QUICKLY A
LO PRES SYSTEM DEVELOPS IN THE OHIO VALLEY AND HOW FAR THIS
DISTURBANCE TRACKS TO THE W...MARGINAL GALES ARE POSSIBLE OVER THE
CENTRAL AND EASTERN PARTS OF THE LAKE AS THE PASSAGE OF COLDER AIR
OVER THE RELATIVELY WARM LAKE WATERS ENHANCES MIXING OF STRONGER
WINDS ALOFT TO THE SURFACE. THESE STRONGER WINDS WILL DIMINISH W-E
AND SHIFT MORE TO THE WNW TUE NIGHT THRU WED NIGHT AS HI PRES BUILDS
TOWARD THE UPPER MIDWEST. LOOK FOR ANOTHER WSHFT TO THE N-NW ON THU
FOLLOWING THE PASSAGE OF ANOTHER TROF ACROSS LAKE SUPERIOR. ONCE THE
TRAILING HI SHIFTS TO THE S ON FRI...A STRONGER SW FLOW WILL
REDEVELOP IN THIS CHANGEABLE WEATHER PATTERN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1031 AM EST MON NOV 28 2011
.SYNOPSIS.../ISSUED AT 1031 AM/
PATCHES OF LIGHT LAKE EFFECT SNOW WILL EVENTUALLY TAPER OFF BY
LATE TODAY. HIGH PRESSURE MAKES A BRIEF APPEARANCE TODAY. SKIES
WILL REMAIN MOSTLY CLOUDY. MORE PRECIPITATION IS IN STORE FOR
PARTS OF THE NORTHERN LOWER PENINSULA TUESDAY INTO TUESDAY
NIGHT...MAINLY FOR AREAS SOUTHEAST OF GAYLORD. EASTERN UPPER WILL
PROBABLY STAY DRY THROUGH THIS PERIOD.
LOCKER/HALBLAUB
&&
.SHORT TERM.../ISSUED AT 1031 AM/...THIS AFTERNOON
...MOSTLY CLOUDY AND CHILLY WITH CONTINUING POTENTIAL FOR PATCHES
OF LIGHT SNOW NEAR THE COASTS THRU AFTN...
UPPER-LEVEL FLOW IS HIGHLY AMPLIFIED OVER N AMERICA...BUT
PROGRESSIVE OVER CANADA AND THE NRN USA. SHRTWV RIDGING IS BUILDING
OVER THE GTLKS IN ADVANCE OF THE NEXT TROF CURRENTLY MOVING THRU
MANITOBA-MONTANA. THE SRN USA FLOW IS MORE BLOCKY AND THE TAIL END
OF AN ANTICYCLONIC WAVE-BREAKING EVENT HAS RESULTED IN A CLOSED LOW
OVER THE TN VALLEY IN THE LAST 24 HRS.
AT THE SFC...YESTERDAY`S COLD FRONT /THAT HAS ESTABLISHED MUCH MORE
SEASONABLE TEMPS/ WAS ALONG THE APPALACHIANS WITH A SFC LOW OVER NRN
GA. HIGH PRES EXTENDED FROM OK TO THE GTLKS. THE NEXT INACTIVE COLD
FRONT WAS MOVING INTO THE NRN PLAINS.
CLOUDS: FOG/REFLECTIVITY PRODUCT OVERLAID WITH 925 MB ANALYSIS SHOWS
THAT MVFR STRATUS IS ASSOCIATED WITH THE LOW-LEVEL THERMAL TROF/COLD
POOL. EROSION OF BACK EDGE IS OCCURRING WITH WAA. INTERESTING TO
NOTE THAT THIS EDGE HAS ONLY PROGRESSED FROM WRN MN BORDER TO THE MS
RIVER IN THE LAST 24 HRS.
INITIAL VIS CHANNEL IMAGERY SHOWS BREAKS AND THIN SPOTS. THESE AND
ANY OTHER BREAKS THAT DEVELOP WILL FILL BACK-IN WITH THERMAL TROF
OVERHEAD. SO MAINTAINED A M/CLOUDY FCST FOR THE REST OF THE DAY AND
INCREASED SKYCOVER AFTER 15Z. THE ERN U.P. COULD TURN P/CLOUDY LATE
BUT IT WILL PROBABLY OCCUR JUST BEFORE SUNSET.
INTERESTING CLOUD MICROPHYSICS. STRATUS IS YIELDING PATCHES OF FINE
SNOW GRAINS. THE COLDEST TEMP /AT THE BASE OF THE INVERSION/ IS -7C.
UNSURE HOW FAR TO EXTEND THIS THRU THE DAY. CONDITIONS APPEAR
FAVORABLE FOR IT TO CONTINUE AND 3KM HRRR IS THE ONLY MODEL SHOWING
IT. SO EXPANDED THE THREAT THRU 21Z...MAINLY FOR IMMEDIATE LAKESHORE
COUNTIES BUT THERE COULD BE FLURRY FURTHER INLAND.
TEMPS: THEY`RE REALLY GOING NOWHERE...HOLDING STEADY. THEY`RE NOT
FOLLOWING THE FCST TEMP CURVE DUE TO CLOUD COVER. SO 3-5F WERE
TRIMMED OFF AFTN HIGHS FROM 4 AM APX FCST.
HALBLAUB
&&
.LONG TERM.../ISSUED AT 445 AM/...TONIGHT AND BEYOND
TONIGHT...THE HIGH PRESSURE GOES VIRTUALLY NO WHERE...REMAINING
OVER NRN LOWER...WHILE THE LOW PRESSURE FROM TENNESSEE AND THE
COLD FRONT OUT TO OUR WEST BEGIN TO CONVERGE ON THE GREAT LAKES.
THE SW WIND PICKS UP A BIT ACROSS NW LOWER AND EASTERN UPPER WITH
ADDITIONAL 925MB WARMING...WHICH SHOULD EAT AWAY AT THE
STRATOCU. HOWEVER...INCREASING HIGH CLOUDS FROM BOTH FEATURES
WILL RESULT IN INCREASING CLOUDINESS FOR WHEREVER IT DOES START OF
ON THE CLEARER SIDE OF THINGS. MODEL CONSENSUS SUGGESTS THAT A
DEEP ATLANTIC MOISTURE FEED INTO THE NORTHWARD PROGRESSING LOW
PRESSURE WILL GET WRAPPED AROUND INTO A TROWEL WHICH LIFTS NORTH
OF THE OHIO RIVER VALLEY NEAR DTX BY DAYBREAK. MEANWHILE...NEAR
THE SAGINAW BAY REGION DEFORMATION ZONE AND FGEN ALOFT SNEAKS IN
OVER THE FAR SE CWA FOR SOME MODEL SUGGESTED LIGHT RAIN
DEVELOPMENT. HOWEVER...ANTECEDENT EXTREMELY DRY AIR MASS WILL BE
DIFFICULT TO MOISTEN...ESPECIALLY WHEN CONSIDERING STRENGTHENING
FGEN AND SHARP CUT OFF TO THE NRN EDGE OF THE RAIN SHIELD. MODEL
SOUNDINGS DO NOT SUPPORT ANY PRECIPITATION...AND LOWERED THE
CHANCE FOR SEEING PRECIP...BUT DID LEAVE A SMALL CHANCE RIGHT
NEAR THE SAG BAY. LOW TEMPS WILL BE IN THE LOW 30S.
TUESDAY THROUGH WEDNESDAY...LOW PRESSURE WILL LIFT THROUGH THE
EASTERN GREAT LAKES AND DEEPEN WHILE PARENT UPPER CUT OFF LOW
WILL TRY AND PHASE TO SOME DEGREE WITH NRN STREAM ENERGY. UPSTREAM
COLD FRONT DROPS IN ACROSS NRN MICHIGAN AND MESHES WITH THE LOW
PRESSURE RESULTING IN STRENGTHENING NORTHERLY WINDS AND DRY
ADVECTION OUT OF EASTERN UPPER. MEANWHILE THE DEFORMATION/FGEN AND
TROWAL LIFTS UP INTO NE LOWER. EXACTLY HOW FAR NORTH THE SHARP
CUTOFF TO THE NRN EDGE OF THE PRECIPITATION MAKES IT...IS STILL A
BIT UNCLEAR. THAT SAID...FEEL THAT THE NW HALF OF THE CWA IS
LIKELY TO SEE NO PRECIPITATION...WHILE A GOOD CHUNK OF NE LOWER IS
GONNA GET A LITTLE DAMP. MODEL SUGGESTIONS OF WARM WEDGE OF AIR
ALOFT (TROWAL) MOVING IN OVER SFC TEMPS LOWERING TO 32F OR LOWER
TUESDAY NIGHT IN PARTS OF THE PRECIP SHIELD ARE MOST LIKELY NOT
GONNA HAPPEN. TEMPERATURES OVER THIS AREA WILL LIKELY REMAIN AT OR
JUST ABOVE FREEZING...AND ANY CHANCE OF NEW NAM SOUNDINGS
SUGGESTING SOME FREEZING RAIN ARE SMALL. HAVE CONTINUED THE THEME
OF RAIN AND SNOW...BUT LOWERED THE POTENTIAL SNOW AMOUNTS DUE TO A
WARMER SCENARIO/HIGHER SNOW/WATER RATIOS. MAYBE AN INCH AROUND THE
SAGINAW BAY. DUE TO THE UNCERTAINTY AND MARGINAL THERMAL REGIMES
WILL CONTINUE TO MENTION THE POTENTIAL FOR ACCUMULATING SNOW IN
THE HWOAPX. THE WEATHER IMPROVES INTO WEDNESDAY AS THE LOW
PRESSURE WORKS ITS WAY OUT OF THE EASTERN GREAT LAKES...TAKING THE
DEEPER MOISTURE AND FORCING OUT OF NE LOWER. OUTSIDE OF NE
LOWER...THE REMAINDER OF THE CWA WILL LIKELY BE UNDER AT LEAST
HIGH LEVEL CLOUDS. SKIES WILL BE CLEAREST ACROSS FAR WESTERN
CHIP/MACK COUNTIES. HIGHS WILL BE IN THE UPPER 30S TO AROUND 40
DEGREES AGAIN.
THURSDAY ONWARD...ONE NORTHERN STREAM SHORTWAVE STILL EXPECTED
THURS-THURS NIGHT FOR POSSIBLE CHANCE AT SNOW...WHILE A BETTER
SHOT MAY DEVELOP OVER THE WEEKEND. NOT MANY CHANGES IN THIS TIME
PERIOD.
SMD
&&
.MARINE.../ISSUED AT 1131 AM/
HIGH PRES IS OVER THE LAKES TODAY...RESULTING IN LIGHT WINDS AND
LOW SEAS. HALBLAUB
THE MAIN MARINE ISSUE WILL BE A LOW PRESSURE SYSTEM LIFTING
THROUGH THE EASTERN GREAT LAKES TUESDAY THROUGH WEDNESDAY. A TIGHT
PRESSURE GRADIENT IS ANTICIPATED WITH DEFINITE SMALL CRAFT
ADVISORIES ACROSS ALL NEARSHORES. THE GALE POTENTIAL IS BECOMING
MORE CERTAIN FOR PORTIONS OF THE NEARSHORES OF LAKE MICHIGAN AND
HURON...MAINLY SURROUNDING NORTHERN LOWER MICHIGAN.
SMD
&&
.AVIATION.../ISSUED AT 628 AM/...VALID FOR 12Z TAFS
WIDESPREAD MVFR CIGS IN STRATOCU TO START OUT THE DAY. THESE
CLOUDS EXTEND AS FAR BACK AS ALL OF WISCONSIN. THIS WILL BE THE
THEME OF THE DAY...AS MVFR CONDITIONS ARE EXPECTED TO PERSIST
THROUGH MOST OF THE DAY UNTIL WARM ADVECTION AND DEVELOPING LAND
BREEZES OUGHT TO BREAK APART THE SHIELD OF CLOUDS. DURING THIS
TIME WE WILL SEE AN INCREASE IN HIGH LEVEL CIRRUS WITH THE
APPROACH OF A COLD FRONT FROM THE WEST...AND A STRENGTHENING LOW
PRESSURE SYSTEM FROM THE SOUTH. THE PRESSURE GRADIENT TIGHTENS
LATE IN THE TAF PERIOD...WITH WINDY CONDITIONS EXPECTED OUT OF THE
NNE TUESDAY.
SMD
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON FOR
LHZ347>349.
LM...GALE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON FOR
LMZ323-342-344>346.
LS...NONE.
&&
$$
WFO APX
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
630 AM EST MON NOV 28 2011
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS /ISSUED AT 514 AM/...
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGING FROM
THE SW CONUS THROUGH THE UPPER MS VALLEY TO HUDSON BAY AND A CUTOFF
LOW OVER THE LOWER MS VALLEY. MAINLY ZONAL NRN STREAM FLOW
PREVAILED FROM THE EPAC THROUGH SRN CANADA AND THE NRN PLAINS. A
SHORTWAVE TROUGH EXTENDED FROM SRN SASK INTO NW MT WAS MOVING
STEADILY TO THE EAST. AT THE SFC...SRLY WINDS WERE INCREASING OVER
MN AND THE ERN DAKOTAS BTWN A TROUGH FROM MANITOBA TO THE WRN PLAINS
AND A RIDGE INTO THE WRN GREAT LAKES. IR 11-3.9 LOOP SHOWED THAT THE
BACK EDGE OF PERSISTENT LOW CLOUDS OVER UPPER MI...WI AND ERN MN WAS
ONLY MAKING SLOW OR LITTLE PROGRESS TO THE EAST. KINL/KMPX/KGRB
SOUNDINGS SHOWED MOIST LAYER TRAPPED BELOW A STRONG 900-850 MB
INVERSION. RADAR INDICATED THAT THE LIGHT LAKE EFFECT SNOW SHOWERS
OR FLURRIES OVER ERN LAKE SUPERIOR HAD DIMINISHED TO NO MORE THAN A
FEW FLURRIES FROM MUNISING EASTWARD.
&&
.DISCUSSION...
TODAY...NAM/RUC 925-900 MB RH PROGS SUGGEST THAT THE LOW CLOUDS
SHOULD DISSIPATE AND/OR DEPART TO THE EAST THIS MORNING AS LOW LEVEL
SW WINDS INCREASE. THIS WOULD LEAVE PARTLY TO MOSTLY SUNNY SKIES
THIS AFTERNOON AS MID/HIGH CLOUDS SUPPORTED BY WAA AHEAD OF THE
PLAINS TROUGH SPREAD INTO THE AREA. HOWEVER...SINCE THE MODELS HAVE
RECENTLY BEEN TOO EAGER TO REMOVE THE LOWER CLOUDS...EXPECT A DELAY
IN CLEARING MAY EXTEND INTO THE AFTERNOON. THIS SHOULD LIMIT MAX
TEMPS TO MAINLY THE MID 30S...WITH SOME UPPER 30S TO AROUND 40
READINGS AT LOCATIONS FAVORED BY SW DOWNSLOPE FLOW.
TONIGHT...THE SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO WILL DRAG
A COLD FRONT/TROUGH THROUGH THE AREA. THE WEAK TO MODERATE QVECTOR
FORCING ACCOMPANYING THE TROUGH WILL REMAIN MAINLY NORTH OF THE CWA.
WITH LITTLE MOISTURE AVAILABLE...NO MEASURABLE PCPN IS EXPECTED.
KEPT TEMPS NEAR THE HIGHER END OF GUIDANCE AS CLOUDS WILL AGAIN KEEP
TEMPS FROM FALLING OFF TOO MUCH.
TUESDAY...STIFF NRLY WINDS WITH INFLUX OF LAKE MOISTURE AND
UPSLOPE FLOW WILL SUPPORT PERSISTENT LOWER CLOUDS OVER THE AREA.
ALTHOUGH THE SHALLOW LOWER CLOUD LAYER EXTENDING ONLY UP TO 900-850
TEMPS AROUND -6C MAY SUGGEST POTENTIAL FOR -FZDZ...A RELATIVELY DRY
SUB CLOUD LAYER WOULD NOT BE FAVORABLE.
TUE NIGHT INTO WED...WITH THE MID LEVEL AND SFC RIDGE BUILDING INTO
THE AREA...ALONG WITH DRY ADVECTION...CLEARING SHOULD TAKE OVER BY
LATE TUE AND LINGER INTO WED MORNING. SO...TEMPS NEAR CONSENSUS
GUIDANCE APPEARED REASONABLE WITH READINGS INTO THE UPPER TEENS
INLAND WEST AND MID 20S NEAR THE LAKES AND OVER THE ERN CWA. TEMPS
SHOULD REBOUND TO THE MID AND UPPER 30S WED.
WED NIGHT INTO THU...THE GFS/ECMWF/GEM SUGGEST THAT ANOTHER
SHORTWAVE AND FRONT MOVING THROUGH THE AREA ACCOMPANIED BY AT LEAST
MODERATE MID LEVEL FGEN WILL SUPPORT AN AREA OF LIGHT SNOW OVER THE
REGION. DIFFERENCES REMAIN WITH THE PLACEMENT/INTENSITY OF THE PCPN.
FOR NOW...ONLY CHANCE POPS WERE INCLUDED.
FRI...CAA IN THE WAKE OF THE FRONT DROPPING 850 MB TEMPS INTO THE
-12C TO -14C...PER GFS/ECMWF RANGE SHOULD GENERATE LES INTO EARLY
FRI FOR NW FLOW SNOWBELTS. ANY LES WOULD BE SHORTLIVED AS THE
PROGRESSIVE PATTERN WOULD LIKELY BRING WAA QUICKLY BACK INTO THE
AREA BY THE END OF THE WEEK.
INTO THE WEEKEND...
MODELS SHOW GENERAL TROUGHING PATTERN INTO THE CNTRL CONUS.
HOWEVER...SIGNIFICANT DIFFERENCES EMERGE REGARDING WHETHER THE DRIER
NRN STREAM WILL DOMINATE WITH MAINLY LES CHANCES (GFS) OR POSSIBLE
PHASING WITH SRN STREAM COULD BRING MORE SUBSTANTIAL MOISTURE/SNOW
INTO THE AREA (ECMWF). FOR NOW...THE FCST LEANS TOWARD THE GFS
SCENARIO WITH TEMPS FALLING INTO THE UPPER 20S AND LOWER 30S BY SUN
WITH LES CHANCES...TYPICAL FOR EARLY WINTER.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
EXPECT PERSISTENT MVFR CIGS TO GRADUALLY GIVE WAY TO VFR CONDITIONS
W-E AS WARMER AND DRIER AIR FROM THE W MAKES ONLY SLOW PROGRESS INTO
THE UPR GRT LKS. IFR CIGS ARE PSBL EARLY AT IWD WITH SHALLOWER INVRN
BASE. ALTHOUGH A COLD FNT WL SWING ACRS THE AREA TNGT...THE TRAILING
AIRMASS IS RELATIVELY WARM. SO THE USUAL LK EFFECT CLDS THAT MIGHT
PLAGUE THE SITES THIS TIME OF YEAR WITH A WSHFT TO THE NNW BEHIND
THE FNT WL LIKELY BE ABSENT OR AT LEAST LESS WDSPRD THAN USUAL. BUT
GUSTY WINDS ARE LIKELY UNDER SHARPENING PRES GRADIENT.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT INCREASNIG SW WINDS UP TO 30 KTS TODAY UNDER SHARPENING PRES
GRADIENT BETWEEN DEPARTING SFC HI OVER THE CENTRAL GREAT LAKES AND
AN APPROACHING COLD FRONT. THERE MAY EVEN BE A FEW GALE FORCE GUSTS
BETWEEN ISLE ROYALE AND THE KEWEENAW WHERE TERRAIN INFLUENCES WILL
ACCENTUATE THIS FLOW. AFTER THIS FRONT PASSES LAKE SUPERIOR
TONIGHT...THERE WILL BE WSHFT TO THE N. DEPENDING ON HOW QUICKLY A
LO PRES SYSTEM DEVELOPS IN THE OHIO VALLEY AND HOW FAR THIS
DISTURBANCE TRACKS TO THE W...MARGINAL GALES ARE POSSIBLE OVER THE
CENTRAL AND EASTERN PARTS OF THE LAKE AS THE PASSAGE OF COLDER AIR
OVER THE RELATIVELY WARM LAKE WATERS ENHANCES MIXING OF STRONGER
WINDS ALOFT TO THE SURFACE. THESE STRONGER WINDS WILL DIMINISH W-E
AND SHIFT MORE TO THE WNW TUE NIGHT THRU WED NIGHT AS HI PRES BUILDS
TOWARD THE UPPER MIDWEST. LOOK FOR ANOTHER WSHFT TO THE N-NW ON THU
FOLLOWING THE PASSAGE OF ANOTHER TROF ACROSS LAKE SUPERIOR. ONCE THE
TRAILING HI SHIFTS TO THE S ON FRI...A STRONGER SW FLOW WILL
REDEVELOP IN THIS CHANGEABLE WEATHER PATTERN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
514 AM EST MON NOV 28 2011
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGING FROM
THE SW CONUS THROUGH THE UPPER MS VALLEY TO HUDSON BAY AND A CUTOFF
LOW OVER THE LOWER MS VALLEY. MAINLY ZONAL NRN STREAM FLOW PREVAILED
FROM THE EPAC THROUGH SRN CANADA AND THE NRN PLAINS. A SHORTWAVE
TROUGH EXTENDED FROM SRN SASK INTO NW MT WAS MOVING STEADILY TO THE
EAST. AT THE SFC...SRLY WINDS WERE INCREASING OVER MN AND THE ERN
DAKOTAS BTWN A TROUGH FROM MANITOBA TO THE WRN PLAINS AND A RIDGE
INTO THE WRN GREAT LAKES. IR 11-3.9 LOOP SHOWED THAT THE BACK EDGE
OF PERSISTENT LOW CLOUDS OVER UPPER MI...WI AND ERN MN WAS ONLY
MAKING SLOW OR LITTLE PROGRESS TO THE EAST. KINL/KMPX/KGRB SOUNDINGS
SHOWED MOIST LAYER TRAPPED BELOW A STRONG 900-850 MB INVERSION.
RADAR INDICATED THAT THE LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES
OVER ERN LAKE SUPERIOR HAD DIMINISHED TO NO MORE THAN A FEW FLURRIES
FROM MUNISING EASTWARD.
&&
.DISCUSSION...
TODAY...NAM/RUC 925-900 MB RH PROGS SUGGEST THAT THE LOW CLOUDS
SHOULD DISSIPATE AND/OR DEPART TO THE EAST THIS MORNING AS LOW LEVEL
SW WINDS INCREASE. THIS WOULD LEAVE PARTLY TO MOSTLY SUNNY SKIES THIS
AFTERNOON AS MID/HIGH CLOUDS SUPPORTED BY WAA AHEAD OF THE PLAINS
TROUGH SPREAD INTO THE AREA. HOWEVER...SINCE THE MODELS HAVE RECENTLY BEEN
TOO EAGER TO REMOVE THE LOWER CLOUDS...EXPECT A DELAY IN CLEARING MAY
EXTEND INTO THE AFTERNOON. THIS SHOULD LIMIT MAX TEMPS TO MAINLY THE
MID 30S...WITH SOME UPPER 30S TO AROUND 40 READINGS AT LOCATIONS
FAVORED BY SW DOWNSLOPE FLOW.
TONIGHT...THE SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO WILL DRAG
A COLD FRONT/TROUGH THROUGH THE AREA. THE WEAK TO MODERATE QVECTOR
FORCING ACCOMPANYING THE TROUGH WILL REMAIN MAINLY NORTH OF THE CWA.
WITH LITTLE MOISTURE AVAILABLE...NO MEASURABLE PCPN IS EXPECTED.
KEPT TEMPS NEAR THE HIGHER END OF GUIDANCE AS CLOUDS WILL AGAIN KEEP
TEMPS FROM FALLING OFF TOO MUCH.
TUESDAY...STIFF NRLY WINDS WITH INFLUX OF LAKE MOISTURE AND
UPSLOPE FLOW WILL SUPPORT PERSISTENT LOWER CLOUDS OVER THE AREA.
ALTHOUGH THE SHALLOW LOWER CLOUD LAYER EXTENDING ONLY UP TO 900-850
TEMPS AROUND -6C MAY SUGGEST POTENTIAL FOR -FZDZ...A RELATIVELY DRY
SUB CLOUD LAYER WOULD NOT BE FAVORABLE.
TUE NIGHT INTO WED...WITH THE MID LEVEL AND SFC RIDGE BUILDING INTO
THE AREA...ALONG WITH DRY ADVECTION...CLEARING SHOULD TAKE OVER BY
LATE TUE AND LINGER INTO WED MORNING. SO...TEMPS NEAR CONSENSUS
GUIDANCE APPEARED REASONABLE WITH READINGS INTO THE UPPER TEENS
INLAND WEST AND MID 20S NEAR THE LAKES AND OVER THE ERN CWA. TEMPS
SHOULD REBOUND TO THE MID AND UPPER 30S WED.
WED NIGHT INTO THU...THE GFS/ECMWF/GEM SUGGEST THAT ANOTHER
SHORTWAVE AND FRONT MOVING THROUGH THE AREA ACCOMPANIED BY AT LEAST
MODERATE MID LEVEL FGEN WILL SUPPORT AN AREA OF LIGHT SNOW OVER THE
REGION. DIFFERENCES REMAIN WITH THE PLACEMENT/INTENSITY OF THE PCPN.
FOR NOW...ONLY CHANCE POPS WERE INCLUDED.
FRI...CAA IN THE WAKE OF THE FRONT DROPPING 850 MB TEMPS INTO THE
-12C TO -14C...PER GFS/ECMWF RANGE SHOULD GENERATE LES INTO EARLY
FRI FOR NW FLOW SNOWBELTS. ANY LES WOULD BE SHORTLIVED AS THE
PROGRESSIVE PATTERN WOULD LIKELY BRING WAA QUICKLY BACK INTO THE
AREA BY THE END OF THE WEEK.
INTO THE WEEKEND...
MODELS SHOW GENERAL TROUGHING PATTERN INTO THE CNTRL CONUS.
HOWEVER...SIGNIFICANT DIFFERENCES EMERGE REGARDING WHETHER THE DRIER
NRN STREAM WILL DOMINATE WITH MAINLY LES CHANCES (GFS) OR POSSIBLE
PHASING WITH SRN STREAM COULD BRING MORE SUBSTANTIAL MOISTURE/SNOW
INTO THE AREA (ECMWF). FOR NOW...THE FCST LEANS TOWARD THE GFS
SCENARIO WITH TEMPS FALLING INTO THE UPPER 20S AND LOWER 30S BY SUN
WITH LES CHANCES...TYPICAL FOR EARLY WINTER.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
NORTH TO NORTHWEST FLOW HAS HELPED KEEP MVFR CIGS IN AT ALL
TERMINALS. WITH LTL MOVEMENT IN CLEARING LINE OVER CENTRAL MN...IT
WILL TAKE SOME TIME FOR CLEARING TO MOVE INTO UPPER MICHIGAN. IN
FACT...CLEARING WILL PROBABLY NOT OCCUR UNTIL LATE MORNING OR AT
LEAST UNTIL AFTER SUNRISE WHEN SW WINDS PICK UP ON BACKSIDE OF HIGH
PRESSURE.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT INCREASNIG SW WINDS UP TO 30 KTS TODAY UNDER SHARPENING PRES
GRADIENT BETWEEN DEPARTING SFC HI OVER THE CENTRAL GREAT LAKES AND
AN APPROACHING COLD FRONT. THERE MAY EVEN BE A FEW GALE FORCE GUSTS
BETWEEN ISLE ROYALE AND THE KEWEENAW WHERE TERRAIN INFLUENCES WILL
ACCENTUATE THIS FLOW. AFTER THIS FRONT PASSES LAKE SUPERIOR
TONIGHT...THERE WILL BE WSHFT TO THE N. DEPENDING ON HOW QUICKLY A
LO PRES SYSTEM DEVELOPS IN THE OHIO VALLEY AND HOW FAR THIS
DISTURBANCE TRACKS TO THE W...MARGINAL GALES ARE POSSIBLE OVER THE
CENTRAL AND EASTERN PARTS OF THE LAKE AS THE PASSAGE OF COLDER AIR
OVER THE RELATIVELY WARM LAKE WATERS ENHANCES MIXING OF STRONGER
WINDS ALOFT TO THE SURFACE. THESE STRONGER WINDS WILL DIMINISH W-E
AND SHIFT MORE TO THE WNW TUE NIGHT THRU WED NIGHT AS HI PRES BUILDS
TOWARD THE UPPER MIDWEST. LOOK FOR ANOTHER WSHFT TO THE N-NW ON THU
FOLLOWING THE PASSAGE OF ANOTHER TROF ACROSS LAKE SUPERIOR. ONCE THE
TRAILING HI SHIFTS TO THE S ON FRI...A STRONGER SW FLOW WILL
REDEVELOP IN THIS CHANGEABLE WEATHER PATTERN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1049 PM CST SUN NOV 27 2011
.DISCUSSION...
/ISSUED 346 PM CST SUN NOV 27 2011/
SUMMARY...LARGELY DRY FORECAST WITH ONLY SMALL POPS IN THE
FORECAST FOR THURSDAY AND NEXT SUNDAY. THREE COLD FRONTS MOVE
THROUGH OVER THE NEXT 7 DAYS...MONDAY NIGHT...WEDNESDAY
NIGHT...AND SATURDAY NIGHT. SLIGHTLY ABOVE NORMAL TEMPS ARE
EXPECTED AHEAD OF THESE BOUNDARIES MONDAY...WEDNESDAY AND
SATURDAY. NEAR NORMAL OR SLIGHTLY BELOW NORMALS TEMPS ARE
EXPECTED BEHIND THE FRONTAL PASSAGES ON TUESDAY...
THURSDAY...FRIDAY AND SUNDAY.
TONIGHT AND TOMORROW...TRICKY TEMP FORECAST: STRATUS DECK HAS BEEN
VERY SLOW TO CLEAR TODAY AND CONTINUES MOVING TO THE EAST AT JUST
7KTS. WITHIN THE LAST HOUR OR SO...WE`RE FINALLY SEEING SOME
THINNING OF THE DECK IN MN. THIS MIGHT BE A SIGN THAT THE CLEARING
IS A BIT FASTER THAN WHAT`S IN THE FORECAST FOR TONIGHT.
HOWEVER...WE WILL LOSE OUR SUN HERE IN THE NEXT COUPLE HOURS...SO
KEPT THE SLOW CLEARING TREND IN THE FORECAST TONIGHT. MIGHT HAVE
TO WAIT FOR THE RIDGE AXIS TO PASS OVERHEAD...WHICH WOULD MATCH UP
FAIRLY WELL WITH THE 925MB RH OFF THE RUC THIS EVENING. THE CLOUDS
WILL OBVIOUSLY HAVE LARGE IMPACT ON THE TEMPERATURES TONIGHT. KEPT
WEST CENTRAL WI IN THE MID 20S AND EVEN LEFT MOST OF THE METRO IN
THE LOWER TO MID 20S. AREAS THAT GET AT LEAST 3-4 HOURS OF CLEAR
SKIES TOMORROW MORNING...WILL LIKELY GET INTO THE TEENS FOR LOWS.
OTHERWISE...THE MERCURY WILL BE HEADING THE OTHER WAY TOMORROW WITH
WARM AIR ADVECTION KICKING IN BETWEEN 06-12Z TONIGHT. SOUTHWEST
WINDS WITH MIXING UP TO 975-925MB OFF THE FORECAST SOUNDINGS WOULD
GIVE US LOW TO MID 40S ALMOST EVERYWHERE TOMORROW. IN
FACT...DOWNSLOPING OFF THE BUFFALO RIDGE IN WESTERN MN SHOULD
YIELD 50S FOR HIGHS. COLD FRONT PASSES THROUGH FROM NW TO SE LATE
TOMORROW AFTERNOON AND TOMORROW EVENING. MIGHT BE A MID DECK OF
CLOUDS WITH THE FRONT BUT NO PRECIPITATION IS EXPECTED.
TUESDAY THROUGH THURSDAY...-4 TO -6 C AT 850MB INDICATING A COOL
DOWN FOR TUESDAY BEHIND THE FRONT BUT CERTAINLY NOTHING OUT OF THE
ORDINARY. THE COOL DOWN WILL BE BRIEF WITH 1000-500MB THICKNESS
ALREADY CLIMBING BETWEEN 540M-546M EARLY WEDNESDAY. ANOTHER FRONT
MOVES THROUGH WEDNESDAY NIGHT AND WITH THIS BOUNDARY THERE MIGHT
BE JUST ENOUGH FORCING AND MOISTURE TO SHAKE OUT A FEW SNOW FLAKES
IN THE STRATO CUMULUS IN THE WAKE OF THE FRONT ON THURSDAY. BOTH
THE 27.12Z GFS/ECMWF HAVE A FEW TENTHS OF SNOW ACCUMULATION ACROSS
CENTRAL MN AND WESTERN WI.
EXTENDED...NO MAJOR SYSTEMS OUT ON THE HORIZON. WOULDN`T BE
SURPRISED IF WE END UP WITH A LITTLE PRECIP NEXT SUNDAY BASED ON
THE PATTERN INDICATED BY THE ECMWF AND TO A LESSER DEGREE THE
LATEST GFS ENSEMBLE. CPC IS FORECASTING BELOW NORMAL TEMPERATURES
FOR MUCH OF THE COUNTRY IN THE 6-14 DAY OUTLOOKS. ALTHOUGH THE
SIGNAL ISN`T QUITE AS STRONG IN MN/WI...IT FINALLY APPEARS WE
SHOULD GET INTO A MORE WINTER-LIKE AIR MASS AFTER NEXT WEEKEND.
&&
.AVIATION.../06Z TAF ISSUANCE/
WESTERN EDGE OF A PERSISTENT STRATUS DECK CONTINUED TO DRIFT SLOWLY
EASTWARD ARND 8 MPH. HOWEVER...THERE HAS BEEN AN EXPANDING HOLE
IN THE STRATUS DECK TO THE WEST OF MSP AND SOUTH OF STC. ALTHOUGH
BASED ON THE LATEST TRENDS AND MOVEMENT...STC SHOULD SCATTER OUT
BY 6Z...WITH SOME LINGERING CIGS POSSIBLE FOR AN HR OR TWO. FOR
MSP...9Z LOOKS AS THOUGH THE BEST TIMING FOR THE STRATUS TO BEGIN
TO BREAK UP...WITH A TEMPORARY PERIOD FROM 9-11Z OF CIGS OF 2.5K.
RNH/EAU WILL LIKELY NOT SEE ANY IMPROVEMENT UNTIL AFT 12Z...AND
MOST LIKELY AFT 13-15Z BASED ON THE LATEST SATELLITE TRENDS. THE
ONLY PROBLEM IS WHETHER ENOUGH DRIER AIR ACCELERATES THE WESTERN
EDGE OF THIS STRATUS DECK FASTER THAN FORECAST IN THE NEXT FEW
HRS.
WNDS WILL BEGIN FROM THE S/SW AND INCREASE DURING THE MORNING...THEN
BECOME MORE W/NW BY THE AFTN/EVENING AS A COLD FRONT MOVES ACROSS
THE AREA. VFR CIGS ARE EXPECTED WITH THIS FRONTAL PASSAGE...ALONG
WITH DRY WX.
MSP...TIMING OF THE STRATUS DECK REMAINS PROBLEMATIC...WITH THE
BEST BET ARND 9-11Z..,UNLESS DRIER AIR ACCELERATES THIS STRATUS
DECK TO THE EAST FASTER. EITHER CASE...BY 12Z...VFR CONDITIONS
ARE EXPECTED. WNDS WILL BE LIGHT FROM THE WEST...THEN SOUTH BY
MORNING...THEN INCREASING FROM THE SSW BY 18Z...SHIFTING TO THE
SW/W BY 21-22Z. NW WNDS ARE EXPECTED BY EVENING.
VFR CONDITIONS ARE EXPECTED THRU TUES. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
109 PM EST MON NOV 28 2011
.SYNOPSIS...
A STALLED FRONTAL BOUNDARY OVER WESTERN NEW YORK AND PENNSYLVANIA
MAY TRIGGER SOME SHOWERS OVER THE FINGER LAKES AND MOHAWK VALLEY
INTO TUESDAY. LOW PRESSURE MOVING NORTHWARD FROM THE TENNESSEE
VALLEY WILL PUSH RAIN INTO THE REGION TUESDAY NIGHT AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED AT 925 AM...MINOR TWEEKS TO CRNT FCST. CDFNT REMAINS
DRAPED ACRS THE BGM CWA WITH 3-HRLY PRES RISES OF 3-4 MB CNTRD
OVER NRN NY. FNT CONTINUE TO MAKE SLOW SWD PROGRESS...WITH ELM NOW
SHOWING A LGT NE WIND. THE RUC APPEARS TO HAVE THE BEST HANDLE ON
THE SITN...SUGGESTING THE FNT MAY CONTINUE TO SAG SLOWLY SWD THIS
AFTN INTO THE REMAINDER OF THE SRN TIER BEFORE LIFTING NWD OVRNGT. WILL
KEEP CHC POPS FOR -SHRA ALONG AND N OF THE FNT FOR THIS AFTN. ACRS
NE PA...SOME BREAKS OF SUNSHINE AND TEMPS ARND OR INTO THE L60S.
PREV BLO...
FNTL BNDRY REMAINS NEARLY STATIONARY OVER THE NW CORNER OF THE
FCST AREA AND WILL REMAIN THE FOCUS OF LGT SHWRS THRU THE DAY.
CRNTS AND RADAR SHOW ONLY VERY LGT RAIN IN THE AREA ATTM...AND DO
NOT XPCT THE INTENSITY TO CHG MUCH AT ALL DURING THE DAY...SO
DESPITE THE LACK OF MVMT...EXCESSIVE RAINFALL AMTS NOT XPCTD.
LATEST SYR TEMPS 62 SO A TRICKY TEMP FCST IN THE GRIDS AS A NON
DIURNAL TEMPS TREND IS XPCTD THIS MRNG AND THIS AFTN AS THE ACTUAL
SFC BNDRY DRFTS SOUTH AND BRINGS COOLER AIR TO THE NW ZONES. NAM12
TEMP FCST SEEMED CLOSEST TO CRNTS AND CAPTURED THE COOLING TREND
UP NORTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
MODELS CONT TO BE IN GOOD AGREEMENT ON THE UPR LOW OVER THE ERN
US. THIS BRINGS A FAIRLY HIGH CONFIDENCE FCST DESPITE THE NRMLY
UNPREDICTABLE NATURE OF CUT OFF OR CLSD LOWS. AS LOW DEEPENS AND
LIFTS NWRD TNGT...OLD BNDRY OVER WRN NY IS FRCD BACK WWRD AND
BRIEF RDGG RETURNS TO THE FCST AREA. THIS SHD KEEP THE FCST AREA
DRY THRU TUE AHD OF THE UPR LOW.
LOW APRCHS TUE NGT AND INITIAL BAND OF RAIN MVES INTO THE AREA.
DEEP SLY FLOW WITH A SUBTROPICAL CONNECTION WILL BRING A PD OF
HEAVY RAIN...MOST LIKELY BETWEEN 00Z AND 06Z WED. GOOD NEWS IS
THAT THE SYSTEM IS PROGRESSIVE SO RAIN DURATION WILL BE SHORT AND
SHD LIMIT THE CNCRN FOR ANY FLOODING ISSUES. LGTR RAIN WILL CONT
LTR TUE NGT INTO WED AS THE UPR LOW LIFTS THRU WRN NY. COOLER AIR
WRAPPING ARND THE BASE OF THE LOW WILL BEGIN THE RETURN TO MORE
SEASONABLE TEMPS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
4 AM UPDATE...THE AREA OF LOW PRESSURE MENTIONED ABOVE WILL
CONTINUE TO MOVE INTO EASTERN QUEBEC WEDNESDAY NIGHT. ON THE
BACKSIDE OF THE LOW ENOUGH COOL AIR AND PRECIP MAY LINGER AROUND
FOR A BRIEF SHOT OF LIGHT SNOW ESPECIALLY IN NY STATE. STILL SOME
UNCERTAINTY WITH THIS SCENARIO WITH THE GFS MORE MILD THAN THE
EURO WHICH WOULD INDICATE MORE OF A MIX WITH RAIN. WE MAY SEE A
BRIEF WINDOW OF LAKE EFFECT LATER WEDNESDAY NIGHT ESPECIALLY IF
THE COLDER EURO IS CORRECT...BEFORE BUILDING HEIGHTS BRING US DRY
WEATHER THURSDAY.
ANOTHER BRIEF SHOT OF CHILLY AIR LATER FRIDAY AND FRIDAY NIGHT MAY
BRING US A PERIOD OF SCT. SNOW SHOWERS WITH LAKE SNOWS POSSIBLE
BEHIND IT. MOST OF THE UPCOMING WEEKEND LOOKS DRY BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EVOLUTION OF A COLD FRONT LATER SUNDAY
INTO EARLY NEXT WEEK. THE GFS IS THE FASTER SOLUTION BRINGING IN
PRECIP BY LATE SUNDAY WHILE ALLOWING FOR COLDER AIR TO MOVE IN AS
EARLY AS SUNDAY NIGHT. THE EURO HOLDS THE FRONT BACK...KEEPS THE
WEEKEND DRY...AND WOULD KEEP US ALL LIQUID THROUGH MONDAY. HPC
GUIDANCE LEANS TOWARD THE EURO AND GIVEN THAT THE GFS IS HAVING
RUN TO RUN CONSISTENCY ISSUES (18Z GFS SUPPORTS SLOWER
SOLUTION...0Z RUN DOES NOT)...MORE CONFIDENT WITH THE EURO. WITH
THAT IN MIND WILL KEEP THE WEEKEND DRY AND WITH 850S ABOVE 0C
THROUGH MONDAY...ANY PRECIP DURING THIS TIME WILL BE IN THE LIQUID
FORM.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
WEAK SURFACE COLD FRONT CURRENTLY DRAPED ACROSS THE SOUTHERN TIER
WITH BOUNDARY JUST NORTH OF KBGM. CIGS ALONG AND BEHIND FRONT MVFR/IFR.
THIS BOUNDARY WILL GRADUALLY LIFT BACK NORTH ACROSS CENTRAL NY
LATE THIS AFTERNOON THROUGH EARLY EVENING. AS THIS OCCURS A SOUTHEAST
FLOW WILL DEVELOP. IN GENERAL CIGS WILL GRADUALLY IMPROVE LATE
THIS AFTERNOON THROUGH EARLY EVENING THEN DETERIORATE AGAIN LATE
TONIGHT ACROSS THE SOUTHERN TERMINALS AS SOUTHEAST FLOW BRINGS LOW
LEVEL MOISTURE INTO REGION.
FOR KRME/KSYR, MVFR CIGS THROUGH MID MORNING TUESDAY WITH
POSSIBLE IFR CIGS AT KRME THROUGH 21Z. AFTER 14Z CIGS AROUND 4K
FT.
AT KITH...IFR CIGS THROUGH EARLY EVENING WITH IMPROVEMENT TO MVFR
THEN POSSIBLE IFR CIGS AGAIN BETWEEN 09Z-13Z, VFR AFTER 14Z.
KELM/KBGM...OCCASIONAL MVFR THROUGH LATE AFTERNOON THEN VFR WITH
LOWERING CIGS INTO THE MVFR CATEGORY AFTER 06Z WITH IFR POSSIBLE
BETWEEN 09Z-13Z. AFTER 14Z CIGS AROUND 4K FT.
KAVP...VFR UNTIL LATE TONIGHT THEN LOWERING INTO MVFR BY 06Z WITH
POSSIBLE DRIZZLE AND IFR CIGS BETWEEN 09Z-13Z. CIGS REMAIN MVFR ON TUESDAY.
LIGHT NORTHERLY WIND BECOMING LIGHT AND VARIABLE THEN SOUTHEAST
LATE TONIGHT AROUND 5 KNOTS INCREASING TO 12 KNOTS ON TUESDAY.
KAVP LIGHT AND VARIABLE WINDS THROUGH LATE TONIGHT.
OUTLOOK...
TUE NIGHT...MVFR/IFR IN RAIN.
WEDNESDAY...PATCHY MVFR IN SHOWERS.
WEDNESDAY NIGHT...PATCHY MVFR IN RAIN/SNOW SHOWERS ESPECIALLY KRME/KSYR.
THURSDAY/THURSDAY NIGHT...VFR.
FRIDAY/FRIDAY NIGHT...PATCHY MVFR IN POSSIBLE SCATTERED RAIN/SNOW
SHOWERS.
SATURDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...
SHORT TERM...DGM
LONG TERM...HEDEN
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
930 AM EST MON NOV 28 2011
.SYNOPSIS...
A STALLED FRONTAL BOUNDARY OVER WESTERN NEW YORK AND PENNSYLVANIA
MAY TRIGGER SOME SHOWERS OVER THE FINGER LAKES AND MOHAWK VALLEY
INTO TUESDAY. LOW PRESSURE MOVING NORTHWARD FROM THE TENNESSEE
VALLEY WILL PUSH RAIN INTO THE REGION TUESDAY NIGHT AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED AT 925 AM...MINOR TWEEKS TO CRNT FCST. CDFNT REMAINS
DRAPED ACRS THE BGM CWA WITH 3-HRLY PRES RISES OF 3-4 MB CNTRD
OVER NRN NY. FNT CONTINUE TO MAKE SLOW SWD PROGRESS...WITH ELM NOW
SHOWING A LGT NE WIND. THE RUC APPEARS TO HAVE THE BEST HANDLE ON
THE SITN...SUGGESTING THE FNT MAY CONTINUE TO SAG SLOWLY SWD THIS
AFTN INTO THE REMAINDER OF THE SRN TIER BEFORE LIFTING NWD OVRNGT. WILL
KEEP CHC POPS FOR -SHRA ALONG AND N OF THE FNT FOR THIS AFTN. ACRS
NE PA...SOME BREAKS OF SUNSHINE AND TEMPS ARND OR INTO THE L60S.
PREV BLO...
FNTL BNDRY REMAINS NEARLY STATIONARY OVER THE NW CORNER OF THE
FCST AREA AND WILL REMAIN THE FOCUS OF LGT SHWRS THRU THE DAY.
CRNTS AND RADAR SHOW ONLY VERY LGT RAIN IN THE AREA ATTM...AND DO
NOT XPCT THE INTENSITY TO CHG MUCH AT ALL DURING THE DAY...SO
DESPITE THE LACK OF MVMT...EXCESSIVE RAINFALL AMTS NOT XPCTD.
LATEST SYR TEMPS 62 SO A TRICKY TEMP FCST IN THE GRIDS AS A NON
DIURNAL TEMPS TREND IS XPCTD THIS MRNG AND THIS AFTN AS THE ACTUAL
SFC BNDRY DRFTS SOUTH AND BRINGS COOLER AIR TO THE NW ZONES. NAM12
TEMP FCST SEEMED CLOSEST TO CRNTS AND CAPTURED THE COOLING TREND
UP NORTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
MODELS CONT TO BE IN GOOD AGREEMENT ON THE UPR LOW OVER THE ERN
US. THIS BRINGS A FAIRLY HIGH CONFIDENCE FCST DESPITE THE NRMLY
UNPREDICTABLE NATURE OF CUT OFF OR CLSD LOWS. AS LOW DEEPENS AND
LIFTS NWRD TNGT...OLD BNDRY OVER WRN NY IS FRCD BACK WWRD AND
BRIEF RDGG RETURNS TO THE FCST AREA. THIS SHD KEEP THE FCST AREA
DRY THRU TUE AHD OF THE UPR LOW.
LOW APRCHS TUE NGT AND INITIAL BAND OF RAIN MVES INTO THE AREA.
DEEP SLY FLOW WITH A SUBTROPICAL CONNECTION WILL BRING A PD OF
HEAVY RAIN...MOST LIKELY BETWEEN 00Z AND 06Z WED. GOOD NEWS IS
THAT THE SYSTEM IS PROGRESSIVE SO RAIN DURATION WILL BE SHORT AND
SHD LIMIT THE CNCRN FOR ANY FLOODING ISSUES. LGTR RAIN WILL CONT
LTR TUE NGT INTO WED AS THE UPR LOW LIFTS THRU WRN NY. COOLER AIR
WRAPPING ARND THE BASE OF THE LOW WILL BEGIN THE RETURN TO MORE
SEASONABLE TEMPS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
4 AM UPDATE...THE AREA OF LOW PRESSURE MENTIONED ABOVE WILL
CONTINUE TO MOVE INTO EASTERN QUEBEC WEDNESDAY NIGHT. ON THE
BACKSIDE OF THE LOW ENOUGH COOL AIR AND PRECIP MAY LINGER AROUND
FOR A BRIEF SHOT OF LIGHT SNOW ESPECIALLY IN NY STATE. STILL SOME
UNCERTAINTY WITH THIS SCENARIO WITH THE GFS MORE MILD THAN THE
EURO WHICH WOULD INDICATE MORE OF A MIX WITH RAIN. WE MAY SEE A
BRIEF WINDOW OF LAKE EFFECT LATER WEDNESDAY NIGHT ESPECIALLY IF
THE COLDER EURO IS CORRECT...BEFORE BUILDING HEIGHTS BRING US DRY
WEATHER THURSDAY.
ANOTHER BRIEF SHOT OF CHILLY AIR LATER FRIDAY AND FRIDAY NIGHT MAY
BRING US A PERIOD OF SCT. SNOW SHOWERS WITH LAKE SNOWS POSSIBLE
BEHIND IT. MOST OF THE UPCOMING WEEKEND LOOKS DRY BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EVOLUTION OF A COLD FRONT LATER SUNDAY
INTO EARLY NEXT WEEK. THE GFS IS THE FASTER SOLUTION BRINGING IN
PRECIP BY LATE SUNDAY WHILE ALLOWING FOR COLDER AIR TO MOVE IN AS
EARLY AS SUNDAY NIGHT. THE EURO HOLDS THE FRONT BACK...KEEPS THE
WEEKEND DRY...AND WOULD KEEP US ALL LIQUID THROUGH MONDAY. HPC
GUIDANCE LEANS TOWARD THE EURO AND GIVEN THAT THE GFS IS HAVING
RUN TO RUN CONSISTENCY ISSUES (18Z GFS SUPPORTS SLOWER
SOLUTION...0Z RUN DOES NOT)...MORE CONFIDENT WITH THE EURO. WITH
THAT IN MIND WILL KEEP THE WEEKEND DRY AND WITH 850S ABOVE 0C
THROUGH MONDAY...ANY PRECIP DURING THIS TIME WILL BE IN THE LIQUID
FORM.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
645 AM UPDATE...A COLD FRONT ACROSS OUR NORTHERN TERMINALS NOW
WILL PRODUCE IFR TO MVFR CIGS THROUGH EARLY AFTERNOON AT KSYR AND
KRME. MVFR VSBYS ARE ALSO POSSIBLE THIS MORNING IN SHOWERS. CIGS
WILL COME UP A BIT THIS AFTERNOON BUT IT WON`T BE UNTIL NEAR 0Z
TONIGHT THAT A RETURN TO VFR IS EXPECTED.
FARTHER SOUTH WITH THE REST OF THE TERMINALS BEING SOUTH OF THE
FRONT AND EXPECTED TO STAY THAT WAY...RESTRICTION FORECAST MUCH
TOUGHER. MVFR CIGS APPEAR MOST LIKELY AT KAVP SINCE WE HAVE
ALREADY HAD THEM. HOWEVER BASED ON OBS THINK THIS WILL CONTINUE TO
BE AN ON AND OFF AND THUS A TEMPO GROUP WILL COVER IT. AT KELM AND
KBGM...WHILE CIGS WILL LIKELY LOWER...FEEL BOTH TERMINALS ARE JUST
FAR ENOUGH AWAY TO KEEP CIGS AT VFR. AT KITH...WITH THE SITE BEING
CLOSEST TO THE FRONT (OUTSIDE OF THE FAR NORTHERN
TERMINALS)...FELT AT LEAST A TEMPO MVFR GROUP WAS WARRANTED THIS
MORNING. AS HEIGHTS BUILD CIGS SHOULD IMPROVE THIS AFTERNOON.
VFR IS EXPECTED EARLY TONIGHT BUT MVFR TO IFR CIGS MAY RETURN LATE
TONIGHT ACROSS THE SOUTHERN TERMINALS WITH MOISTURE TRAPPED
UNDERNEATH AN INVERSION.
OUTLOOK...
MON NGT...IFR/MVFR. PERIODS OF RAIN AND FOG.
TUE THRU THU...PATCHY MVFR IN SCT -SHRA. SCT -SHSN AND MVFR/BRIEF
IFR POSSIBLE BEGINNING WED.
FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
SHORT TERM...DGM
LONG TERM...HEDEN
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
138 AM EST MON NOV 28 2011
.SYNOPSIS...
WEAKENING FRONT AND INCREASING MOISTURE TONIGHT INTO MONDAY...WILL
RESULT IN THICKENING CLOUDS WITH SOME LIGHT SHOWERS OR PATCHY
DRIZZLE. HOWEVER...OUR MAIN BATCH OF RAIN WILL COME FROM A LOW
PRESSURE SYSTEM MOVING THROUGH THE REGION TUESDAY AFTERNOON
THROUGH TUESDAY NIGHT. SOME SHOWERS MAY LINGER INTO WEDNESDAY.
BEHIND THE SYSTEM...TEMPERATURES WILL COOL DOWN TO NEAR NORMAL
LEVELS DURING THE SECOND HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
1030 PM UPDATE... IN THE LAST COUPLE OF HRS...PCPN HAS STARTING
EDGING SLOWLY BACK TWDS THE W. BEING THAT THE SFC FRNT HAS
EFFECTIVELY STALLED ACRS SRN ONT/LK ERIE/OH ATTM...AND THAT DEEP-LYRD
S TO SWLY FLOW WILL BE INCRG IN THE NEXT 12-24 HRS...WE DON`T
EXPECT ANY EWD ADVANCEMENT IN THE NEAR-TERM. WE`VE ADJUSTED
POP/WX GRIDS ACCORDINGLY.
ALSO...TEMPS HAVEN`T FALLEN MUCH AT ALL SO FAR THIS EVE...AND
WE`VE NUDGED OVERNIGHT MINS UP SVRL DEGREES.
8 PM UPDATE... THE LEADING EDGE OF THE -SHRA HAVE MADE IT TO ABT
A KELZ-KPEO-KSYR-KRME LN ATTM. NEAR-TERM NWP GUIDANCE CONTINUES TO
INDICATE THAT ANY FURTHER EWD PUSH TO THE LGT PCPN OVERNIGHT WILL
BE SMALL...AND BASED ON RECENT RADAR TRENDS...WE`RE INCLINED TO GO
ALG WITH THIS THINKING. THUS...SCTD TO NUMEROUS WORDING FOR -SHRA
WILL BE INDICATED IN OUR NRN/WRN ZNS OVERNIGHT...WITH LTL IF ANY
PCPN FARTHER TO THE S AND E...SAVE FOR SOME PATCHY DRZL IN PTNS OF
THE CATSKILLS AND POCONOS TWDS 12Z.
ONLY MINOR TWEAKS WERE MADE TO TEMP/DEW PT GRIDS THROUGH 06Z.
PREV DISC... 4 PM UPDATE...TEMPERATURES TOPPED OUT ROUGHLY 13 TO 17 DEGREES
ABOVE NORMAL...BEING HELD BACK FROM GOING FURTHER ONLY BECAUSE OF
THICKENING HIGH CLOUDS. FRONT IS APPROACHING FROM THE WEST BUT
STRUGGLING...WITH MAINLY ONLY VIRGA SO FAR EXCEPT FOR EXTREME
WESTERN PA AND NY. ONE WEAK WAVE TRAVELING THROUGH THE BRISK
SOUTHWEST FLOW WILL MANAGE TO SKIM STEUBEN COUNTY AND SOME OF THE
WESTERN FINGER LAKES WITH LIGHT SHOWERS DURING THE NEXT FEW
HOURS...THE REST OF THE AREA WILL CONTINUE TO SEE THICKENING HIGH
TO MID LEVEL CLOUDS.
A BIT OF A SQUEEZE PLAY TONIGHT INTO MONDAY MORNING...AS FRONT
STALLS OUT IN OUR NORTHWESTERN ZONES WITH LIGHT SHOWERS COMING OUT
OF TOP-DOWN MOISTENING FROM UPPER LEVELS...YET ALSO SHALLOW MARINE
MOISTURE ATTEMPTS TO RIDE IN ON SOUTHERLY LOW LEVEL FLOW. RUC AND
18Z NAM HAVE BACKED OFF SOMEWHAT ON THIS IDEA HOWEVER...WITH LIGHT
SURFACE WIND VEERING TO INCLUDE SOME WESTERLY COMPONENT...WHICH IS
NOT AS FAVORABLE FOR MARINE MOISTURE TO REACH INTO THE AREA. I
HAVE LIMITED PATCHY DRIZZLE MENTION TO SOME OF THE
POCONOS/CATSKILLS REGION SUSCEPTIBLE TO UPSLOPE FLOW...LATER
TONIGHT INTO EARLY MONDAY MORNING. FARTHER NORTHWEST...NOT AS
MUCH LOW LEVEL MOISTURE...YET ENOUGH MOISTURE IN MID/HIGH LEVELS
FOR LIGHT SHOWERS. CLOUDS HANG AROUND THROUGH MONDAY
AFTERNOON...THOUGH WITH ANY SHOWERS DIMINISHING AS WEAK FRONT
BEGINS TO SLOWLY SHIFT NORTHWARD.
WITH AMOUNT OF CLOUD COVER...ESPECIALLY LATE TONIGHT THROUGH
MONDAY...WILL BE STAYING ON WARM SIDE OF GUIDANCE FOR LOWS
TONIGHT...AND COOLER THAN THE MODELS FOR HIGHS MONDAY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
GOOD MODEL AGREEMENT ON BIG PICTURE FOR UPPER LOW TO PROGRESSIVELY
MOVE THROUGH THE AREA...WITH MODEL CONSENSUS GIVING US OUR MAIN
BATCH OF RAIN LATE TUESDAY INTO TUESDAY NIGHT. WHILE THERE WILL BE
AN ATLANTIC SUBTROPICAL FEED OF MOISTURE...SPEED OF SYSTEM WILL
MINIMIZE ANY THREAT FOR WATER PROBLEMS. AT THIS TIME WE ARE
EXPECTING AREAL AVERAGE OF LESS THAN AN INCH OF RAINFALL.
HOWEVER...SOME MARGINAL INSTABILITY EVIDENT AS NEGATIVELY TILTED
FRONT COMES THROUGH TUESDAY EVENING...TO THE POINT THAT LATER
SHIFTS MAY NEED TO CONSIDER ADDING MENTION OF THUNDER. WITH
DELAYED TIMING OF FRONT...TEMPERATURES LOOK TO GET QUITE WARM ON
TUESDAY.
COLD CORE OF UPPER LOW PASSES DIRECTLY OVERHEAD WEDNESDAY...AND
EXPECTING SCATTERED SHOWERS IN THE WRAP AROUND MOISTURE OF THE
COMMA HEAD. DESPITE STRONG COLD AIR ADVECTION...925-850MB
TEMPERATURES DO NOT SUPPORT SHOWERS CHANGING OVER TO SNOW DURING
THE DAY WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
PERIOD BEGINS WITH VIGOROUS STORM SYSTEM EXITING TO THE EAST, AND
HIGH PRESSURE BUILDING NORTHWARD FROM THE LOWER OHIO VALLEY.
A WEAK LOW PRESSURE CENTER AND ASSOCIATED FRONT WILL MOVE OVER
LAKE ONTARIO EARLY FRIDAY, BRINGING WITH IT A CHANCE FOR A RAIN OR
SNOW SHOWER.
A TROF WILL DIG INTO ONTARIO PROVINCE SATURDAY INTO SUNDAY, WITH
SOME JET ACTIVITY ALONG THE US/CANADIAN BORDER. THIS WILL BRING
A BETTER CHANCE FOR SNOW SHOWERS, ESPECIALLY OVER NY STATE, THIS
WEEKEND.
TEMPERATURES WILL FLUCTUATE BETWEEN SYSTEMS, BUT OVERALL WILL BE
TRENDING BACK TOWARD SEASONABLY COOL READINGS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
130 AM UPDATE...A COLD FRONT ACROSS WESTERN NEW YORK WILL STALL ACROSS OR
NEAR THE NORTHERN TERMINALS BY DAYBREAK. BEHIND THIS FRONT IFR
CIGS HAVE DEVELOPED OVER WESTERN NY AT KBUF AND KIAG. THE HRRR
ALONG WITH THE LATEST GFS AND NAM SOUNDINGS SHOW IFR CIGS
DEVELOPING AT KRME AND KSYR BY 12Z. SOME UNCERTAINTY EXISTS WITH
HOW FAR SOUTH THE FRONT WILL PUSH AND ULTIMATELY THE IFR RESTRICTIONS.
DECIDED TO CONTINUE TO PREVAIL MVFR CIGS DURING THIS TIME WITH
JUST A TEMPO GROUP OF IFR. IF WE GO DOWN TO IFR...IFR CIGS WILL
LIKELY PERSIST THROUGH AT LEAST MIDDAY.
TOUGHER CALL AT THE SOUTHERN TERMINALS. THE FRONT MENTIONED ABOVE
WILL NOT MOVE THROUGH THESE TERMINALS SO IFR TO MVFR CIGS THAT THE
MODELS CONTINUE TO INDICATE ARE MUCH MORE UNCERTAIN. DESPITE
REMAINING SOUTH OF THE COLD FRONT...THE MODELS SHOWS MVFR TO IFR
(AT THE ELEVATED SITES) CIGS DEVELOPING NEAR 12Z...AND FORM THIS
DECK OVERHEAD OR IN PLACE. WITH NO UPSTREAM OBS TO SUPPORT THIS...
JUST TOO LITTLE CONFIDENCE TO INCLUDE MORE THAN AN MVFR TEMPO
GROUP FOR CIGS JUST AT THE ELEVATED SITES (KITH/KBGM) AROUND 12Z.
WILL CONTINUE TO MONITOR AND UPDATE AS NEEDED WITH THE 09Z UPDATE.
BEYOND THIS MORNING CIGS IMPROVE LATER TODAY AND TONIGHT AS HIGH
PRESSURE BUILDS IN AND VFR RETURNS.
OUTLOOK...
MON NGT...IFR/MVFR. PERIODS OF RAIN AND FOG.
TUE THRU THU...PATCHY MVFR IN SCT -SHRA. SCT -SHSN AND MVFR/BRIEF
IFR POSSIBLE BEGINNING WED.
FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MLJ/MDP
SHORT TERM...MDP
LONG TERM...DJP
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
654 AM EST MON NOV 28 2011
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTH NORTHEAST ALONG A STALLED FRONT
WHICH WILL CONTINUE THE WET WEATHER ACROSS THE AREA. THE LOW WILL
MOVE ACROSS THE REGION ON TUESDAY. COLD AIR WRAPPING IN BEHIND THE
LOW WILL CHANGE LINGERING RAIN SHOWERS OVER TO SNOW SHOWERS BEFORE
THE PRECIPITATION ENDS ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ALTHOUGH THERE HAVE BEEN SOME BREAKS IN THE PRECIPITATION...RAIN
CONTINUES PRETTY MUCH AREA WIDE WITH PLENTY MORE UPSTREAM. AS THE
DAY PROGRESSES...LOW PRESSURE WILL APPROACH AND PULL THE OLD FRONT
BACK WEST INTO THE FORECAST AREA. THIS WILL ALSO ALLOW THE MAIN
PRECIPITATION AXIS TO SHIFT WEST SLIGHTLY. THERE SHOULD BE SOME
DRYING IN THE EASTERN COUNTIES WHERE THE FRONT PASSES AGAIN. BUT
NOT CONVINCED THAT IT WILL BE AS SHARP A CUT OFF IN PRECIPITATION
AS THE NAM AND RUC ARE SUGGESTING. HOWEVER IT SHOULD BE ENOUGH
FOR TEMPERATURES TO WARM MORE IN THOSE LOCATIONS THAN POINTS TO
THE WEST.
APPEARS THAT RAINFALL AMOUNTS WILL BE SLIGHTLY HIGHER IN THE TRI-
STATE AREA. BUT EVEN THERE IT SHOULD BE LESS THAN AN INCH IN A
MOSTLY LIGHT STEADY RAIN. THIS COULD LEAD TO SOME PONDING PROBLEMS
BUT POTENTIAL FOR SIGNIFICANT FLOODING DOES NOT LOOK PARTICULARLY
HIGH AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
LOW PRESSURE WILL OCCLUDE AS IT APPROACHES THE REGION TONIGHT AND
LIFTS ACROSS THE AREA TOMORROW. RAIN WILL CONTINUE UNTIL DRY AIR
THAT HAS WRAPPED INTO THE SYSTEM PUSHES NORTH TUESDAY AFTERNOON
AND EVENING. THERE COULD BE A HEAVIER BURST OF RAIN ALONG AND
AHEAD OF THE OCCLUDED FRONT/LOW BUT FOR THE MOST PART THIS SHOULD
BE A CONTINUATION OF LIGHT STEADY RAIN. THERE COULD EVENTUALLY END
UP BEING SOME MINOR AREAL FLOOD ISSUES. ALSO RIVERS WILL RISE IN
RESPONSE TO THE RAINFALL WITH THE POTENTIAL FOR A FEW POINTS TO GO
INTO FLOOD. THIS HEIGHTEN FLOOD POTENTIAL STILL APPEARS TO BE A
DAY OUT. SO WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO.
PRECIPITATION AND COLDER AIR WILL WRAP BACK ACROSS THE AREA
TUESDAY NIGHT. THIS WILL RESULT IN RAIN SHOWERS CHANGING TO SNOW
SHOWERS. THERE COULD BE SOME LIGHT ACCUMULATIONS PARTICULARLY ON
GRASSY SURFACES. AN INCH OR SO IS POSSIBLE IN THE FAR NORTHWEST
COUNTIES WHICH WILL BE NEAR A DEFORMATION ZONE AND THUS GREATER
PRECIPITATION AMOUNTS. SNOW SHOWERS WILL CONTINUE INTO WEDNESDAY
AS A SECONDARY TROUGH ROTATES AROUND THE DEPARTING LOW. CONDITIONS
WILL IMPROVE BY WEDNESDAY AFTERNOON WITH CLEARING WORKING IN FROM
THE WEST.
TEMPERATURES WILL BE CHALLENGING PARTICULARLY TONIGHT AND TUESDAY
WITH THE APPROACH AND PASSAGE OF THE LOW/OCCLUDED FRONT. EXPECT A
MILD NIGHT WITH TEMPERATURES RISING IN SOME LOCATIONS. THEN COLDER
AIR WILL OVERSPREAD THE REGION ON TUESDAY RESULTING IN MORNING
HIGHS AND FALLING TEMPERATURES. HAVE GONE SLIGHTLY ABOVE GUIDANCE
FOR LOWS TUESDAY NIGHT AND USED A MOS BLEND ON WEDNESDAY WITH COLD
ADVECTION AND MOSTLY CLOUDY SKIES NOT ALLOWING FOR MUCH OF A WARM
UP.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD IN FOR THE BEGINNING OF THE PERIOD. A
WEAK FRONT WILL SLIDE BY TO THE NORTH ON FRIDAY. MODELS HAVE COME
INTO AGREEMENT THAT THERE IS LIMITED PRECIPITATION POTENTIAL AT
BEST WITH THIS BOUNDARY. ANOTHER HIGH WILL QUICKLY TRAVERSE THE
AREA ON SATURDAY. THEN ANOTHER FRONT WILL MOVE IN FOR SUNDAY. BUT
IT APPEARS THAT THIS LATTER BOUNDARY WILL BE ABLE TO TAP MORE
MOISTURE. SO HAVE INCLUDED CHANCE POPS THEN.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AN AREA OF LOW PRESSURE SOUTH OF THE TAF SITES WILL MOVE NORTH
TODAY AND TONIGHT. MVFR TO IFR CONDITIONS CAN BE EXPECTED FOR MOST OF THE
TAF PERIOD ALTHOUGH A BRIEF PERIOD OF VFR CONDITIONS WILL BE
POSSIBLE. WIDESPREAD RAIN WILL CONTINUE THROUGH THE DAY TODAY.
SOME DRIER AIR WILL TRY TO WORK INTO EASTERN TAF SITES FOR A FEW
HOURS EARLY TONIGHT HOWEVER PRECIPITATION WILL QUICKLY FILL BACK
INTO THE AREA. A FEW WIND GUSTS UPWARDS OF 18 TO 20 KNOTS WILL BE
POSSIBLE TODAY AS WELL. THE AREA OF LOW PRESSURE WILL BEGIN TO
MOVE ACROSS THE SOUTHERN TAF SITES LATE IN THE TAF PERIOD. THIS
WILL ALLOW WINDS TO CHANGE DIRECTION AND FOR CIGS TO BEGIN TO
IMPROVE SLIGHTLY.
OUTLOOK...MVFR/IFR CIGS/VSBYS THROUGH WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
454 AM EST MON NOV 28 2011
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTH NORTHEAST ALONG A STALLED FRONT
WHICH WILL CONTINUE THE WET WEATHER ACROSS THE AREA. THE LOW WILL
MOVE ACROSS THE REGION ON TUESDAY. COLD AIR WRAPPING IN BEHIND THE
LOW WILL CHANGE LINGERING RAIN SHOWERS OVER TO SNOW SHOWERS BEFORE
THE PRECIPITATION ENDS ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ALTHOUGH THERE HAVE BEEN SOME BREAKS IN THE PRECIPITATION...RAIN
CONTINUES PRETTY MUCH AREA WIDE WITH PLENTY MORE UPSTREAM. AS THE
DAY PROGRESSES...LOW PRESSURE WILL APPROACH AND PULL THE OLD FRONT
BACK WEST INTO THE FORECAST AREA. THIS WILL ALSO ALLOW THE MAIN
PRECIPITATION AXIS TO SHIFT WEST SLIGHTLY. THERE SHOULD BE SOME
DRYING IN THE EASTERN COUNTIES WHERE THE FRONT PASSES AGAIN. BUT
NOT CONVINCED THAT IT WILL BE AS SHARP A CUT OFF IN PRECIPITATION
AS THE NAM AND RUC ARE SUGGESTING. HOWEVER IT SHOULD BE ENOUGH
FOR TEMPERATURES TO WARM MORE IN THOSE LOCATIONS THAN POINTS TO
THE WEST.
APPEARS THAT RAINFALL AMOUNTS WILL BE SLIGHTLY HIGHER IN THE TRI-
STATE AREA. BUT EVEN THERE IT SHOULD BE LESS THAN AN INCH IN A
MOSTLY LIGHT STEADY RAIN. THIS COULD LEAD TO SOME PONDING PROBLEMS
BUT POTENTIAL FOR SIGNIFICANT FLOODING DOES NOT LOOK PARTICULARLY
HIGH AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
LOW PRESSURE WILL OCCLUDE AS IT APPROACHES THE REGION TONIGHT AND
LIFTS ACROSS THE AREA TOMORROW. RAIN WILL CONTINUE UNTIL DRY AIR
THAT HAS WRAPPED INTO THE SYSTEM PUSHES NORTH TUESDAY AFTERNOON
AND EVENING. THERE COULD BE A HEAVIER BURST OF RAIN ALONG AND
AHEAD OF THE OCCLUDED FRONT/LOW BUT FOR THE MOST PART THIS SHOULD
BE A CONTINUATION OF LIGHT STEADY RAIN. THERE COULD EVENTUALLY END
UP BEING SOME MINOR AREAL FLOOD ISSUES. ALSO RIVERS WILL RISE IN
RESPONSE TO THE RAINFALL WITH THE POTENTIAL FOR A FEW POINTS TO GO
INTO FLOOD. THIS HEIGHTEN FLOOD POTENTIAL STILL APPEARS TO BE A
DAY OUT. SO WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO.
PRECIPITATION AND COLDER AIR WILL WRAP BACK ACROSS THE AREA
TUESDAY NIGHT. THIS WILL RESULT IN RAIN SHOWERS CHANGING TO SNOW
SHOWERS. THERE COULD BE SOME LIGHT ACCUMULATIONS PARTICULARLY ON
GRASSY SURFACES. AN INCH OR SO IS POSSIBLE IN THE FAR NORTHWEST
COUNTIES WHICH WILL BE NEAR A DEFORMATION ZONE AND THUS GREATER
PRECIPITATION AMOUNTS. SNOW SHOWERS WILL CONTINUE INTO WEDNESDAY
AS A SECONDARY TROUGH ROTATES AROUND THE DEPARTING LOW. CONDITIONS
WILL IMPROVE BY WEDNESDAY AFTERNOON WITH CLEARING WORKING IN FROM
THE WEST.
TEMPERATURES WILL BE CHALLENGING PARTICULARLY TONIGHT AND TUESDAY
WITH THE APPROACH AND PASSAGE OF THE LOW/OCCLUDED FRONT. EXPECT A
MILD NIGHT WITH TEMPERATURES RISING IN SOME LOCATIONS. THEN COLDER
AIR WILL OVERSPREAD THE REGION ON TUESDAY RESULTING IN MORNING
HIGHS AND FALLING TEMPERATURES. HAVE GONE SLIGHTLY ABOVE GUIDANCE
FOR LOWS TUESDAY NIGHT AND USED A MOS BLEND ON WEDNESDAY WITH COLD
ADVECTION AND MOSTLY CLOUDY SKIES NOT ALLOWING FOR MUCH OF A WARM
UP.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD IN FOR THE BEGINNING OF THE PERIOD. A
WEAK FRONT WILL SLIDE BY TO THE NORTH ON FRIDAY. MODELS HAVE COME
INTO AGREEMENT THAT THERE IS LIMITED PRECIPITATION POTENTIAL AT
BEST WITH THIS BOUNDARY. ANOTHER HIGH WILL QUICKLY TRAVERSE THE
AREA ON SATURDAY. THEN ANOTHER FRONT WILL MOVE IN FOR SUNDAY. BUT
IT APPEARS THAT THIS LATTER BOUNDARY WILL BE ABLE TO TAP MORE
MOISTURE. SO HAVE INCLUDED CHANCE POPS THEN.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
CONDITIONS CURRENTLY RANGE FROM VFR TO IFR ACROSS THE AREA TAF
SITES ALTHOUGH MOST LOCATIONS ARE IN THE MVFR TO IFR CATEGORY.
WIDESPREAD RAIN WILL CONTINUE THROUGH THE OVERNIGHT HOURS AND INTO
THE DAY ON MONDAY. A FEW WIND GUSTS WILL ALSO BE POSSIBLE DURING
THE DAYTIME HOURS ON MONDAY ACROSS THE AREA. WIND GUSTS WILL
GENERALLY BE IN THE 18 TO 20 KNOT RANGE. SOME DRIER AIR WILL TRY
TO WORK IN BRIEFLY FROM THE EAST MONDAY EVENING AND REFLECTED THIS
IN THE TAFS. AS THE LOW NEARS THE AREA MONDAY NIGHT HOWEVER CIGS
WILL LOWER AND RAIN WILL ONCE AGAIN RETURN TO THE TAF SITES.
OUTLOOK...MVFR/IFR CIGS/VSBYS MONDAY NIGHT INTO WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
926 PM CST TUE NOV 29 2011
.UPDATE...
HAD CANCELLED WIND ADVISORY EARLY AS A COMBINATION OF RELAXING
SURFACE PRESSURE GRADIENT AS DEEP SURFACE LOW PULLS AWAY TO THE
EAST...AND DECOUPLING WITH PARTLY CLOUDY SKIES...HAS LOWERED WIND
SPEEDS AND GUSTS WELL BELOW CRITERIA. WILL STILL A FEW ISOLATED
GUSTS BETWEEN 25 AND 30 MPH ALONG THE LAKE UNTIL MIDNIGHT...
ESPECIALLY FROM MILWAUKEE SOUTH...BUT NO ADVISORY GUSTS EXPECTED.
REST OF FORECAST LOOKS ON TRACK.
&&
.AVIATION/06Z TAFS/...
WAS CONSIDERING LOW-LEVEL WIND SHEAR AT EASTERN TAF SITES...BUT
ENOUGH SURFACE WIND...AND CURRENT PROFILER SPEEDS AND FORECAST
WINDS AT AND BELOW 2000 FEET WILL STAY JUST BELOW THE
DIFFERENTIAL NEEDED FOR MENTIONING. WILL CONTINUE TO MONITOR.
OTHERWISE...WINDS WILL CONTINUE TO EASE OVERNIGHT AS DEEP LOW
PULLS AWAY TO THE EAST AND RIDGE OF HIGH PRESSURE MOVES OVERHEAD.
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD.
&&
.MARINE...WILL END GALE WARNING FOR NORTHERN 2 ZONES AT 06Z AND
SOUTHERN 2 ZONES AT 09Z. SOUTH MID-LAKE BUOY IS STILL GUSTING TO
37 KNOTS AND THE CHICAGO CRIB IS UP TO 38 KNOTS. OFFSHORE
COMPONENT TO WIND HAS ALLOWED DECOUPLING RIGHT UP TO THE LAKE
SHORE...SO SHORELINE OBS NOT REACHING CRITERIA...BUT RUC MODEL
SOUNDINGS SHOW MIXING UP TO 35 TO 37 KNOT WINDS UNTIL BETWEEN 04Z
AND 06Z NORTH...AND 07Z TO 09Z SOUTH WITH DEEPER MIXING OVER THE
RELATIVELY WARMER WATERS WILL KEEP GALE GUSTS OVER THE NEARSHORE
WATERS UNTIL THEN. WILL NEED TO HAVE SMALL CRAFT ADVISORIES UNTIL
AT LEAST MID-MORNING WEDNESDAY AFTER GALE CANCELLATION.
&&
.PREV DISCUSSION... /ISSUED 253 PM CST TUE NOV 29 2011/
TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
WINDY CONDITIONS IN THE EAST WILL SUBSIDE THIS EVENING AND OVERNIGHT
AS LOW PRESSURE TO THE SOUTHEAST PULLS AWAY FROM THE AREA. WILL KEEP
WIND ADVISORY EXPIRATION TIME OF MIDNIGHT...WITH HIGHER GUSTS ALONG
THE SHORE STILL POSSIBLE. WINDS SHOULD DROP OFF QUICKER AWAY FROM
THE LAKE AS DAYTIME MIXING IS LOST. CLOUDS ARE ALSO EXPECTED TO
DECREASE AS THE LOW MOVES AWAY...WITH CLEAR SKIES IN THE WEST THIS
EVENING...AND SKIES BECOMING CLEAR TOWARD MORNING IN THE EAST.
THOUGH SFC WINDS WILL BECOME LIGHT AWAY FROM THE LAKE...BOUNDARY
LAYER WINDS WILL STAY UP A BIT...SO TEMPS SHOULD NOT FALL TOO
FAR...WITH NEAR NORMAL LOWS EXPECTED.
HIGH PRESSURE WILL BRING SUNNY SKIES TO START THE DAY
WEDNESDAY...WITH HIGH CLOUDS THEN PUSHING IN FROM THE WEST LATE
MORNING AND INTO THE AFTERNOON. SHOULD BE A TOLERABLE DAY...WITH
LIGHTER WINDS AND HIGHS AROUND 40.
WEDNESDAY NIGHT...FORECAST CONFIDENCE IS HIGH.
UPPER RIDGE SLIDES SOUTHEAST OVERNIGHT...ALLOWING HIGH CLOUDS TO
BEGIN SPILLING IN WITH THE APPROACH OF THE NEXT UPSTREAM TROUGH.
THESE CLOUDS SHOULD HELP TO KEEP TEMPS FROM DROPPING TOO
HARD...STILL CHILLY THOUGH.
THURSDAY AND THURSDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
NEXT UPPER TROF AND SFC TROF/COLD FRONT MOVE THROUGH THE AREA
DURING THIS TIME. THE SFC TROF IS WELL OUT AHEAD OF THE UPPER
FEATURE WITH COLD ADVECTION AND DRIER AIR OVERSPREADING THE AREA
QUICKLY. THIS SHOULD NEGATE MUCH OF THE IMPACT OF THE SHORT WAVE
LAGGING BEHIND. WILL CARRY SLIGHT CHANCE POPS WITH ITS PASSAGE. IT
REMAINS VERY MOISTURE STARVED WITH THE NAM ACTUALLY HAVING IT COME
THROUGH DRY.
FRIDAY AND FRIDAY NIGHT...FORECAST CONFIDENCE IS HIGH.
HIGH PRESSURE SLIDES ACROSS BEHIND THE EXITING FRONT AND AHEAD OF
THE NEXT SYSTEM. LOOKS CHILLY...BUT THERE SHOULD BE PLENTY OF
SUNSHINE ON FRIDAY. CLOUDS INCREASE FRIDAY NIGHT.
SATURDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
THE ECMWF HAS BEEN STEADY EDDIE WITH THE NEXT SYSTEM KICKING OUT
OF THE SOUTHWEST U.S. THIS WEEKEND. A TIGHTENING H8 BAROCLINIC
ZONE IS FORECAST TO SET UP FROM WISCONSIN BACK INTO OKLAHOMA AND
TEXAS FRIDAY NIGHT AND SATURDAY. THE ECMWF/GFS/GEM ALL KICK OUT A
PIECE OF ENERGY FROM THE CUT OFF UPPER LOW SOUTH OF THE 4-CORNERS
AREA. IT THEN RACES NORTHEAST INTO THE WESTERN GREAT LAKES BY
SUNDAY. THE LOWER LEVELS RESPOND WITH A DEVELOPING LOW PRESSURE
SYSTEM...NOTHING MAJOR...BUT ENOUGH TO PULL UP A DECENT SURGE OF
MOISTURE...ABOUT 3G/KG AT 750-700MB. CONDENSATION PRESSURE
DEFICITS TANK TO THE LOWER SINGLE DIGITS. IT/S LOOKING MORE LIKELY
WE WILL GET SOME PRECIP SATURDAY NIGHT INTO SUNDAY. THE
ECMWF/GFS/GEM ALL HAVE SOME PRECIP ACROSS THE AREA DURING THIS
TIME. THE BIGGEST QUESTION WILL BE WHAT TYPE. THE GFS IS COLD AND
WOULD SUPPORT A MORE SNOWY SCENARIO...WHILE THE ECMWF IS WARMER
WITH A RAIN OR RAIN/SNOW MIX TO START...CHANGING OVER TO LIGHT
SNOW LATER SATURDAY NIGHT. THE GEM LOOKS TO BE SOMEWHERE IN THE
MIDDLE. SO...CONFIDENCE IS HIGH WE/LL GET PRECIP...BUT LOW ON THE
TYPE AND WHAT IMPACTS MAY RESULT. IF THE GFS VERIFIES...WE/D
LIKELY BE LOOKING AT AN SNOW ADVISORY FOR AT LEAST THE CENTRAL AND
NORTHWEST PORTION OF THE FORECAST AREA. STAY TUNED.
SUNDAY NIGHT AND MONDAY...FORECAST CONFIDENCE IS MEDIUM.
SUNDAY NIGHT SHOULD DRY OUT WITH COLD AIR SPILLING IN AS THE LOW
PULLS AWAY. THE GFS AND THE ECMWF BRING IN A QUICK LITTLE CLIPPER
SYSTEM ACROSS THE GREAT LAKES ON MONDAY. THIS IS A PRETTY DRY
LITTLE GUY...BUT MAY BE GOOD FOR SOME LIGHT SNOW OR FLURRIES.
CERTAINLY IS LOOKING LIKE A COLD START TO NEXT WEEK.
AVIATION/00Z TAFS/...MVFR CIGS LIKELY TO CONTINUE THROUGH LATE
AFTERNOON IN THE EAST. LOW LEVEL FLOW TURNS MORE NORTH TO NORTHWEST
THIS EVENING AND INTO THE NIGHT...WHILE LOW PRESSURE TO THE
SOUTHEAST PULLS AWAYS. THIS SHOULD RESULT IN LOWER CIGS SCATTERING
OUT EARLY THIS EVENING. VFR CONDITIONS THEN EXPECTED THROUGH
WEDNESDAY AS HIGH PRESSURE MOVES OVERHEAD.
BREEZY WINDY CONDITIONS OUT OF THE NORTH...HIGHEST TOWARD THE
LAKE...WILL PERSIST THROUGH LATE AFTERNOON. WINDS IN GENERAL WILL
THEN BECOME LIGHTER THIS EVENING AND OVERNIGHT AS THE HIGH
APPROACHES. GUSTY WINDS ARE STILL POSSIBLE ALONG THE LAKE SHORE THIS
EVENING THOUGH WHILE THE WINDS REMAIN OUT OF THE NORTH. AN OFFSHORE
COMPONENT TO THE WINDS LATER IN THE EVENING WILL ALLOW WINDS TO
SETTLE DOWN ALONG THE LAKE.
MARINE...GALE WARNING REMAINS IN EFFECT THROUGH TONIGHT. NORTHERLY
WINDS WILL SLOWLY DECREASE THIS EVENING AND OVERNIGHT...LIKELY
FALLING BELOW WARNING CRITERIA LATE IN THE NIGHT. SMALL CRAFT GUSTS
STILL POSSIBLE IN THE MORNING...WITH WAVES GREATER THAN 4 FEET ALSO
LINGERING UNTIL AFTERNOON. THUS A SMALL CRAFT ADVISORY WILL BE
NEEDED UNTIL LATE MORNING OR EARLY AFTERNOON WEDNESDAY ONCE THE GALE
WARNING ENDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...GALE WARNING UNTIL 3 AM CST WEDNESDAY FOR LMZ645-646.
GALE WARNING UNTIL MIDNIGHT CST TONIGHT FOR LMZ643-644.
&&
$$
UPDATE...REM
TONIGHT/WEDNESDAY AND AVIATION/MARINE...DDV
WEDNESDAY NIGHT THROUGH TUESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CST MON NOV 28 2011
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
310 AM CST MON NOV 28 2011
THE MAIN STORIES IN THE SHORT TERM ARE WITH THE PESKY STRATUS
THAT IS CURRENTLY DRAPED OVER MUCH OF THE REGION ALONG WITH THE
CHANCES FOR A LIGHT ACCUMULATION OF SNOW ON THURSDAY.
CURRENTLY...A SURFACE RIDGE OF HIGH PRESSURE EXTENDS FROM THE
SOUTHERN PLAINS THROUGH SOUTHEAST MINNESOTA AND LAKE SUPERIOR. A
STUBBORN LOW LEVEL STRATUS DECK REMAINS IN PLACE ACROSS MUCH OF
THE REGION ALONG THE EASTERN PERIPHERY OF THIS RIDGE. THE WESTERN
EDGE OF THIS CLOUD SHIELD HAS STARTED TO DRIFT EASTWARD OVERNIGHT
ACROSS EASTERN MINNESOTA AND SHOULD COME THROUGH THE FORECAST
AREA FROM WEST TO EAST TODAY. THE AREA OF LEAST CONFIDENCE IN THE
CLEARING OCCURRING IS IN FAR NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN AS THE STRATUS HAS BEEN SLOW TO MOVE IN CENTRAL IOWA.
THE 28.00Z NAM AND GFS APPEAR TO HAVE INITIALIZED TOO LOW ON THE
RH UNDER THE 900MB INVERSION...BUT THE 28.05Z RUC SEEMS TO HAVE A
BETTER HANDLE ON THE LOW LEVEL MOISTURE. THUS...HAVE GONE WITH A
PESSIMISTIC BLEND OF THE RUC AND PURE IR SATELLITE EXTRAPOLATION
TO GET THE CLEARING TREND DOWN. THIS CLOUD COVER WILL HAVE AN
IMPACT ON TEMPERATURES TODAY WITH THE HIGHEST VALUES TO THE
NORTHWEST WHERE THE SUN WILL BE OUT LONGER.
AFTER A BRIEF CLEAR PERIOD GOING INTO THE EVENING...MID TO HIGH
LEVEL CLOUD COVER WILL BE ON THE INCREASE AS A MID LEVEL TROUGH
NEAR SASKATCHEWAN DROPS SOUTHEAST INTO THE REGION. AS THIS TROUGH
INTERACTS WITH A CUTOFF LOW IN THE SOUTHEASTERN US IT WILL LOSE
SOME OF ITS BETTER FORCING WITH PV ADVECTION SHOWING A RAPID
DECREASE. WHILE PRECIPITATION LOOKS UNLIKELY...THIS TROUGH WILL
BRING A COLD FRONT ALONG WITH IT THAT WILL TRACK THROUGH TONIGHT.
WITH A SURFACE LOW TRACKING TO THE NORTH THROUGH THE OHIO RIVER
VALLEY AND A RIDGE OF HIGH PRESSURE FOLLOWING THE COLD FRONT...THE
UPPER MISSISSIPPI RIVER VALLEY WILL BE STUCK IN BETWEEN THESE TWO
FEATURES WITH A TIGHTENING PRESSURE GRADIENT. AS A RESULT...WIND
GUSTS OF 20-30KT WILL BE POSSIBLE ON TUESDAY...PARTICULARLY ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN WHERE THE GRADIENT WILL BE
THE TIGHTEST.
THIS RIDGE OF HIGH PRESSURE WILL GRADUALLY SLIDE EASTWARD INTO THE
REGION WEDNESDAY INTO EARLY THURSDAY AND PROVIDE FOR SOME FAIRLY
COOL TEMPERATURES WITH LOWS IN THE TEENS. THE NEXT FEATURE OF NOTE IS
WITH A MID LEVEL TROUGH THAT IS EXPECTED TO DROP INTO THE REGION
ON THURSDAY. OVER THE PAST FEW DAYS...THE MODELS HAVE BEEN PRETTY
LOW ON PRODUCING ANY QPF OUT OF THIS FEATURE. HOWEVER...THE LATEST
TREND IS TO BE MUCH STRONGER WITH THIS MID LEVEL FEATURE AND
THEY SHOW QUITE A BIT OF QG FORCING WITH TROUGH. TEMPERATURES
WOULD BE COLD ENOUGH TO SUPPORT ALL SNOW ALONG AND BEHIND THE COLD
FRONT WHERE THE PRECIPITATION IS EXPECTED TO FORM. THIS LOOKS TO
BE A FAIRLY QUICK HITTER WITH LESS THAN A 6 HOUR WINDOW OF SEEING
THE SNOWFALL...SO TOTALS SHOULD BE FAIRLY LIGHT IF THIS DOES TAKE
SHAPE WITH THE SNOW ENDING THURSDAY NIGHT AS THE FORCING DROPS TO
THE SOUTHEAST OF THE REGION.
.LONG TERM...FRIDAY THROUGH SUNDAY NIGHT
310 AM CST MON NOV 28 2011
AFTER A RIDGE OF HIGH PRESSURE MOVES THROUGH ON FRIDAY...THE FOCUS
WILL BE ON THE WEEKEND AND WHETHER PRECIPITATION WILL FILL IN FROM
THE SOUTHWEST AS THE 27.00Z AND 26.12Z ECMWF IS SUGGESTING. THE
27.00Z SHOWS THE MID LEVEL CUT OFF LOW OVER THE FOUR CORNERS
REGION GETTING PICKED UP INTO THE NEXT TROUGH THAT TRACKS THROUGH
THE NORTHERN PLAINS SATURDAY INTO SUNDAY. THE 27.00Z
GFS...HOWEVER...KEEPS THIS LOW OUT OVER THE DESERT AND BRINGS THE
NORTHERN STREAM TROUGH THROUGH A LITTLE LESS AMPLIFIED. WITH A
COLD FRONT STALLED OUT JUST TO THE SOUTHEAST...PRECIPITATION IS
EXPECTED TO DEVELOP IN THE VICINITY OF IT AS THIS WAVE GETS PICKED
UP. TEMPERATURES SHOULD BE COLD ENOUGH TO SUPPORT ALL SNOW...SO
THIS SYSTEM WILL HAVE TO BE MONITORED FOR TRENDS AS THE GFS WOULD
SUGGEST THAT CONDITIONS WOULD BE DRY UNTIL SUNDAY NIGHT WHEN A
SYSTEM DROPS OUT OF SOUTHWESTERN CANADA.
&&
.AVIATION...THIS AFTERNOON THROUGH TUESDAY
1130 AM CST MON NOV 28 2011
MVFR/IFR STRATUS CLOUDS REMAIN TRAPPED ACROSS THE FCST AREA...UNDER
A VERY STRONG SUBSIDENCE INVERSION NEAR 925MB. THE MOISTURE/CLOUDS
ARE SHALLOWER TODAY...MORE IN THE 1000-1500 FT DEPTH RANGE. VIS
IMAGERY DID SHOW SOME THINNING OF THE STRATUS OVER PARTS OF THE FCST
AREA LATE THIS MORNING...THUS TRENDED TAFS TOWARD BKN DECKS FOR MID/
LATE AFTERNOON HOURS. APPEARS THE AREA WILL HAVE TO WAIT FOR MORE OF
A WEST OR NORTHWEST PUSH FROM THE LOW LEVEL WINDS TO FINALLY GET THE
LOW CLOUDS OUT OF THE AREA VERY LATE THIS AFTERNOON OR EARLY THIS
EVENING. LOW LEVEL WINDS GRADUALLY BECOME MORE SOUTHWEST AND WEST
LATER THIS AFTERNOON/EVENING AS LOW PRESSURE MOVES ACROSS SOUTHERN
CAN AND A COLD FRONT APPROACHES FROM THE NORTHWEST. NORTHWEST AND
NORTH GRADIENT WINDS INCREASE OVER THE AREA TONIGHT...BEHIND THE
FRONT AND ON THE BACK SIDE OF A STRONG LOW MOVING THRU THE OH
VALLEY. CLOUDS WITH THE FRONT MAINLY HIGH LEVEL. ONCE FRONT PUSHES
SOUTH ACROSS THE TAF SITES AND TAKES THE LOW CLOUDS WITH IT...VFR
CONDITIONS EXPECTED FROM THE MID EVENING HOURS TONIGHT THRU TUE AND
WED AS DRY HIGH PRESSURE FROM THE NORTHERN PLAINS BUILDS INTO THE
UPPER MIDWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
310 AM CST MON NOV 28 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
543 AM CST MON NOV 28 2011
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
310 AM CST MON NOV 28 2011
THE MAIN STORIES IN THE SHORT TERM ARE WITH THE PESKY STRATUS
THAT IS CURRENTLY DRAPED OVER MUCH OF THE REGION ALONG WITH THE
CHANCES FOR A LIGHT ACCUMULATION OF SNOW ON THURSDAY.
CURRENTLY...A SURFACE RIDGE OF HIGH PRESSURE EXTENDS FROM THE
SOUTHERN PLAINS THROUGH SOUTHEAST MINNESOTA AND LAKE SUPERIOR. A
STUBBORN LOW LEVEL STRATUS DECK REMAINS IN PLACE ACROSS MUCH OF
THE REGION ALONG THE EASTERN PERIPHERY OF THIS RIDGE. THE WESTERN
EDGE OF THIS CLOUD SHIELD HAS STARTED TO DRIFT EASTWARD OVERNIGHT
ACROSS EASTERN MINNESOTA AND SHOULD COME THROUGH THE FORECAST
AREA FROM WEST TO EAST TODAY. THE AREA OF LEAST CONFIDENCE IN THE
CLEARING OCCURRING IS IN FAR NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN AS THE STRATUS HAS BEEN SLOW TO MOVE IN CENTRAL IOWA.
THE 28.00Z NAM AND GFS APPEAR TO HAVE INITIALIZED TOO LOW ON THE
RH UNDER THE 900MB INVERSION...BUT THE 28.05Z RUC SEEMS TO HAVE A
BETTER HANDLE ON THE LOW LEVEL MOISTURE. THUS...HAVE GONE WITH A
PESSIMISTIC BLEND OF THE RUC AND PURE IR SATELLITE EXTRAPOLATION
TO GET THE CLEARING TREND DOWN. THIS CLOUD COVER WILL HAVE AN
IMPACT ON TEMPERATURES TODAY WITH THE HIGHEST VALUES TO THE
NORTHWEST WHERE THE SUN WILL BE OUT LONGER.
AFTER A BRIEF CLEAR PERIOD GOING INTO THE EVENING...MID TO HIGH
LEVEL CLOUD COVER WILL BE ON THE INCREASE AS A MID LEVEL TROUGH
NEAR SASKATCHEWAN DROPS SOUTHEAST INTO THE REGION. AS THIS TROUGH
INTERACTS WITH A CUTOFF LOW IN THE SOUTHEASTERN US IT WILL LOSE
SOME OF ITS BETTER FORCING WITH PV ADVECTION SHOWING A RAPID
DECREASE. WHILE PRECIPITATION LOOKS UNLIKELY...THIS TROUGH WILL
BRING A COLD FRONT ALONG WITH IT THAT WILL TRACK THROUGH TONIGHT.
WITH A SURFACE LOW TRACKING TO THE NORTH THROUGH THE OHIO RIVER
VALLEY AND A RIDGE OF HIGH PRESSURE FOLLOWING THE COLD FRONT...THE
UPPER MISSISSIPPI RIVER VALLEY WILL BE STUCK IN BETWEEN THESE TWO
FEATURES WITH A TIGHTENING PRESSURE GRADIENT. AS A RESULT...WIND
GUSTS OF 20-30KT WILL BE POSSIBLE ON TUESDAY...PARTICULARLY ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN WHERE THE GRADIENT WILL BE
THE TIGHTEST.
THIS RIDGE OF HIGH PRESSURE WILL GRADUALLY SLIDE EASTWARD INTO THE
REGION WEDNESDAY INTO EARLY THURSDAY AND PROVIDE FOR SOME FAIRLY
COOL TEMPERATURES WITH LOWS IN THE TEENS. THE NEXT FEATURE OF NOTE IS
WITH A MID LEVEL TROUGH THAT IS EXPECTED TO DROP INTO THE REGION
ON THURSDAY. OVER THE PAST FEW DAYS...THE MODELS HAVE BEEN PRETTY
LOW ON PRODUCING ANY QPF OUT OF THIS FEATURE. HOWEVER...THE LATEST
TREND IS TO BE MUCH STRONGER WITH THIS MID LEVEL FEATURE AND
THEY SHOW QUITE A BIT OF QG FORCING WITH TROUGH. TEMPERATURES
WOULD BE COLD ENOUGH TO SUPPORT ALL SNOW ALONG AND BEHIND THE COLD
FRONT WHERE THE PRECIPITATION IS EXPECTED TO FORM. THIS LOOKS TO
BE A FAIRLY QUICK HITTER WITH LESS THAN A 6 HOUR WINDOW OF SEEING
THE SNOWFALL...SO TOTALS SHOULD BE FAIRLY LIGHT IF THIS DOES TAKE
SHAPE WITH THE SNOW ENDING THURSDAY NIGHT AS THE FORCING DROPS TO
THE SOUTHEAST OF THE REGION.
.LONG TERM...FRIDAY THROUGH SUNDAY NIGHT
310 AM CST MON NOV 28 2011
AFTER A RIDGE OF HIGH PRESSURE MOVES THROUGH ON FRIDAY...THE FOCUS
WILL BE ON THE WEEKEND AND WHETHER PRECIPITATION WILL FILL IN FROM
THE SOUTHWEST AS THE 27.00Z AND 26.12Z ECMWF IS SUGGESTING. THE
27.00Z SHOWS THE MID LEVEL CUT OFF LOW OVER THE FOUR CORNERS
REGION GETTING PICKED UP INTO THE NEXT TROUGH THAT TRACKS THROUGH
THE NORTHERN PLAINS SATURDAY INTO SUNDAY. THE 27.00Z
GFS...HOWEVER...KEEPS THIS LOW OUT OVER THE DESERT AND BRINGS THE
NORTHERN STREAM TROUGH THROUGH A LITTLE LESS AMPLIFIED. WITH A
COLD FRONT STALLED OUT JUST TO THE SOUTHEAST...PRECIPITATION IS
EXPECTED TO DEVELOP IN THE VICINITY OF IT AS THIS WAVE GETS PICKED
UP. TEMPERATURES SHOULD BE COLD ENOUGH TO SUPPORT ALL SNOW...SO
THIS SYSTEM WILL HAVE TO BE MONITORED FOR TRENDS AS THE GFS WOULD
SUGGEST THAT CONDITIONS WOULD BE DRY UNTIL SUNDAY NIGHT WHEN A
SYSTEM DROPS OUT OF SOUTHWESTERN CANADA.
&&
.AVIATION...THROUGH 12Z TUESDAY
543 AM CST MON NOV 28 2011
STUBBORN IFR/MVFR STRATUS HANGING TOUGH THIS MORNING AS HIGH
PRESSURE RIDGE AXIS OVERHEAD KEEPS MOISTURE TRAPPED UNDER THE
ASSOCIATED SUBSIDENCE INVERSION. MODELS CONTINUE TO SHOW THE RIDGE
AXIS SHIFTING SLOWLY SOUTHEAST OF THE AREA THIS AFTERNOON. SOUTHWEST
WINDS ON THE BACKSIDE OF THE HIGHS WILL HOPEFULLY AID IN
MIXING/ERODING THE STRATUS AT KRST AROUND 16Z AND AT KLSE AROUND
20Z. NEXT CONCERN WILL BE COLD FRONTAL PASSAGE TONIGHT AND BRISK
POST-FRONTAL NORTH WINDS THROUGH TUESDAY. EXPECTING NORTH WINDS TO
PICK UP AFTER MIDNIGHT AS COLD PUSH AND PRESSURE GRADIENT INCREASES
ACROSS THE AREA WITH GUSTS IN THE 20 TO 25KT RANGE. ALSO...SOME
INDICATIONS IN THE MODELS THAT A BAND OF SCATTERED TO BROKEN
STRATOCUMULUS MAY FORM BEHIND THE FRONT AFT 03Z. FOR NOW...WENT WITH
SCT020 AT KRST AND SCT025 AT KLSE...BUT MAY HAVE TO WATCH FOR
POTENTIAL MVFR CEILINGS. WILL PASS THIS CONCERN TO THE DAY SHIFT FOR
THE 18Z TAF ISSUANCE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
310 AM CST MON NOV 28 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
310 AM CST MON NOV 28 2011
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
310 AM CST MON NOV 28 2011
THE MAIN STORIES IN THE SHORT TERM ARE WITH THE PESKY STRATUS
THAT IS CURRENTLY DRAPED OVER MUCH OF THE REGION ALONG WITH THE
CHANCES FOR A LIGHT ACCUMULATION OF SNOW ON THURSDAY.
CURRENTLY...A SURFACE RIDGE OF HIGH PRESSURE EXTENDS FROM THE
SOUTHERN PLAINS THROUGH SOUTHEAST MINNESOTA AND LAKE SUPERIOR. A
STUBBORN LOW LEVEL STRATUS DECK REMAINS IN PLACE ACROSS MUCH OF
THE REGION ALONG THE EASTERN PERIPHERY OF THIS RIDGE. THE WESTERN
EDGE OF THIS CLOUD SHIELD HAS STARTED TO DRIFT EASTWARD OVERNIGHT
ACROSS EASTERN MINNESOTA AND SHOULD COME THROUGH THE FORECAST
AREA FROM WEST TO EAST TODAY. THE AREA OF LEAST CONFIDENCE IN THE
CLEARING OCCURRING IS IN FAR NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN AS THE STRATUS HAS BEEN SLOW TO MOVE IN CENTRAL IOWA.
THE 28.00Z NAM AND GFS APPEAR TO HAVE INITIALIZED TOO LOW ON THE
RH UNDER THE 900MB INVERSION...BUT THE 28.05Z RUC SEEMS TO HAVE A
BETTER HANDLE ON THE LOW LEVEL MOISTURE. THUS...HAVE GONE WITH A
PESSIMISTIC BLEND OF THE RUC AND PURE IR SATELLITE EXTRAPOLATION
TO GET THE CLEARING TREND DOWN. THIS CLOUD COVER WILL HAVE AN
IMPACT ON TEMPERATURES TODAY WITH THE HIGHEST VALUES TO THE
NORTHWEST WHERE THE SUN WILL BE OUT LONGER.
AFTER A BRIEF CLEAR PERIOD GOING INTO THE EVENING...MID TO HIGH
LEVEL CLOUD COVER WILL BE ON THE INCREASE AS A MID LEVEL TROUGH
NEAR SASKATCHEWAN DROPS SOUTHEAST INTO THE REGION. AS THIS TROUGH
INTERACTS WITH A CUTOFF LOW IN THE SOUTHEASTERN US IT WILL LOSE
SOME OF ITS BETTER FORCING WITH PV ADVECTION SHOWING A RAPID
DECREASE. WHILE PRECIPITATION LOOKS UNLIKELY...THIS TROUGH WILL
BRING A COLD FRONT ALONG WITH IT THAT WILL TRACK THROUGH TONIGHT.
WITH A SURFACE LOW TRACKING TO THE NORTH THROUGH THE OHIO RIVER
VALLEY AND A RIDGE OF HIGH PRESSURE FOLLOWING THE COLD FRONT...THE
UPPER MISSISSIPPI RIVER VALLEY WILL BE STUCK IN BETWEEN THESE TWO
FEATURES WITH A TIGHTENING PRESSURE GRADIENT. AS A RESULT...WIND
GUSTS OF 20-30KT WILL BE POSSIBLE ON TUESDAY...PARTICULARLY ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN WHERE THE GRADIENT WILL BE
THE TIGHTEST.
THIS RIDGE OF HIGH PRESSURE WILL GRADUALLY SLIDE EASTWARD INTO THE
REGION WEDNESDAY INTO EARLY THURSDAY AND PROVIDE FOR SOME FAIRLY
COOL TEMPERATURES WITH LOWS IN THE TEENS. THE NEXT FEATURE OF NOTE IS
WITH A MID LEVEL TROUGH THAT IS EXPECTED TO DROP INTO THE REGION
ON THURSDAY. OVER THE PAST FEW DAYS...THE MODELS HAVE BEEN PRETTY
LOW ON PRODUCING ANY QPF OUT OF THIS FEATURE. HOWEVER...THE LATEST
TREND IS TO BE MUCH STRONGER WITH THIS MID LEVEL FEATURE AND
THEY SHOW QUITE A BIT OF QG FORCING WITH TROUGH. TEMPERATURES
WOULD BE COLD ENOUGH TO SUPPORT ALL SNOW ALONG AND BEHIND THE COLD
FRONT WHERE THE PRECIPITATION IS EXPECTED TO FORM. THIS LOOKS TO
BE A FAIRLY QUICK HITTER WITH LESS THAN A 6 HOUR WINDOW OF SEEING
THE SNOWFALL...SO TOTALS SHOULD BE FAIRLY LIGHT IF THIS DOES TAKE
SHAPE WITH THE SNOW ENDING THURSDAY NIGHT AS THE FORCING DROPS TO
THE SOUTHEAST OF THE REGION.
.LONG TERM...FRIDAY THROUGH SUNDAY NIGHT
310 AM CST MON NOV 28 2011
AFTER A RIDGE OF HIGH PRESSURE MOVES THROUGH ON FRIDAY...THE FOCUS
WILL BE ON THE WEEKEND AND WHETHER PRECIPITATION WILL FILL IN FROM
THE SOUTHWEST AS THE 27.00Z AND 26.12Z ECMWF IS SUGGESTING. THE
27.00Z SHOWS THE MID LEVEL CUT OFF LOW OVER THE FOUR CORNERS
REGION GETTING PICKED UP INTO THE NEXT TROUGH THAT TRACKS THROUGH
THE NORTHERN PLAINS SATURDAY INTO SUNDAY. THE 27.00Z
GFS...HOWEVER...KEEPS THIS LOW OUT OVER THE DESERT AND BRINGS THE
NORTHERN STREAM TROUGH THROUGH A LITTLE LESS AMPLIFIED. WITH A
COLD FRONT STALLED OUT JUST TO THE SOUTHEAST...PRECIPITATION IS
EXPECTED TO DEVELOP IN THE VICINITY OF IT AS THIS WAVE GETS PICKED
UP. TEMPERATURES SHOULD BE COLD ENOUGH TO SUPPORT ALL SNOW...SO
THIS SYSTEM WILL HAVE TO BE MONITORED FOR TRENDS AS THE GFS WOULD
SUGGEST THAT CONDITIONS WOULD BE DRY UNTIL SUNDAY NIGHT WHEN A
SYSTEM DROPS OUT OF SOUTHWESTERN CANADA.
&&
.AVIATION...THROUGH 06Z TUESDAY
1136 PM CST SUN NOV 27 2011
CONCERN CONTINUES TO BE ON WHEN STRATUS DECK WILL CLEAR THE TAF
SITES. SATELLITE TRENDS THROUGHOUT THE EVENING INDICATE THE BACK
EDGE OF THE STRATUS DECK HAS BEEN SLOWLY PUSHING EASTWARD. ONCE
AGAIN MODELS NOT DEPICTING THE LOW LEVEL MOISTURE WELL AT ALL AND
THUS HAVE BASED CLEARING TREND BASED ON THE BACK EDGE
SPEED AND POSITION OF THE SURFACE RIDGE AND 925MB WINDS...WHICH IS
SIMILAR TO THE TIMING IN THE 00Z TAFS SO NO MAJOR CHANGES. ONCE
STRATUS CLEARS...VFR CONDITIONS WILL PREVAIL WITH ONLY A FEW
CLOUDS EXPECTED AFTER 00Z TUESDAY.
A COLD FRONT PUSHES THROUGH THE AREA AFTER MONDAY EVENING...WITH
THE WINDS BECOMING NORTHWESTERLY. THE PRESSURE GRADIENT DOES
TIGHTEN...AND EXPECT WINDS AT 12 KNOTS OR GREATER AFTER 04Z AT
KRST...WITH THE INCREASE AT KLSE AFTER 06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
310 AM CST MON NOV 28 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1136 PM CST SUN NOV 27 2011
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
255 PM CST SUN NOV 27 2011
MAIN FORECAST CONCERN IS ON CLOUDS/TEMPERATURES TONIGHT INTO MONDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED TROUGHING OVER BRITISH COLUMBIA...RIDGING FROM SOUTHERN
CALIFORNIA NORTHEASTWARD INTO SOUTHERN MANITOBA...AND TROUGHING FROM
JAMES BAY SOUTHWEST THROUGH WISCONSIN AND DOWN INTO EASTERN TEXAS.
WITH THE FORECAST AREA ON THE WEST SIDE OF THIS LATTER UPPER
TROUGHING...MID TO UPPER LEVEL SUBSIDENCE IS OCCURRING. THIS CAN BE
SEEN ON 12Z SOUNDINGS FROM ABR...MPX AND DVN. ALSO OF NOTE ON THE
MPX AND DVN SOUNDINGS IS A NEAR TO FULLY SATURATED LAYER FROM 910MB
TO AT LEAST 850MB...REPRESENTATIVE OF THE STRATUS DECK IN PLACE AT
THE TIME. LATEST VISIBLE SATELLITE IMAGERY SHOWED THE STRATUS
COVERING THE ENTIRE FORECAST AREA AND EXTENDING WEST TO A
NORTH-SOUTH LINE THROUGH WINDOM MINNESOTA. GOING A LITTLE FARTHER
WEST...A SURFACE RIDGE IS PRESENT ALONG THE DAKOTAS/MINNESOTA
BORDER. NORTHWEST WINDS REMAIN GUSTY AHEAD OF THE RIDGE WITH GUSTS
OF 20-25 KT OVER THE FORECAST AREA. TEMPERATURES HAVE ALSO STRUGGLED
TO RISE MUCH TODAY...DUE TO A COMBINATION OF THE STRATUS LIMITING
DIURNAL HEATING AND 850MB TEMPS OF -9C OBSERVED AT MPX ON ITS 12Z
SOUNDING.
MUCH OF THE SHORT TERM PERIOD LOOKS QUIET FOR THE FORECAST AREA...
THOUGH THERE ARE A FEW FEATURES TO WATCH. FIRST IS THE SOUTHERN END
OF THE CURRENT UPPER TROUGH IN EAST TEXAS. ALL MODELS AGREE ON THE
SOUTHERN END CLOSING OFF INTO AN UPPER LOW OVER THE SOUTHEASTERN
U.S. MONDAY INTO MONDAY NIGHT...WHICH RESULTS IN SURFACE LOW
DEVELOPMENT ON ITS NORTH SIDE OVER KENTUCKY AND TENNESSEE. THE UPPER
AND SURFACE LOWS THEN GET LIFTED NORTHEAST THROUGH THE EASTERN U.S.
FOR TUESDAY INTO WEDNESDAY...IN RESPONSE TO THE CURRENT BRITISH
COLUMBIA TROUGH MOVING THROUGH THE FORECAST AREA ON TUESDAY. AS OF
NOW IT APPEARS ANY DEFORMATION PRECIPITATION ON THE NORTHWEST SIDE
OF THE UPPER AND SURFACE LOWS WILL STAY TO THE SOUTHEAST...THANKS TO
THAT BRITISH COLUMBIA UPPER TROUGH...PERHAPS REACHING AT MOST THE
ROCKFORD ILLINOIS AREA. OTHERWISE...MUCH OF THE REST OF THE TIME THE
FORECAST AREA SHOULD BE DOMINATED BY SUBSIDENCE AND DRY AIR...DUE TO
UPPER RIDGING COMING ACROSS ON MONDAY AND AGAIN TUESDAY NIGHT INTO
WEDNESDAY...RESULTING IN DRY CONDITIONS.
CLOUD COVER FORECAST IS PROBLEMATIC...ESPECIALLY TONIGHT WITH THE
STRATUS STUCK IN PLACE BELOW THE SUBSIDENCE INVERSION. TYPICALLY TO
GET RID OF STRATUS IN THESE CASES...ESPECIALLY THIS TIME OF YEAR
WITH THE VERY LOW SUN ANGLE...THE SURFACE RIDGE NEEDS TO MOVE IN
AND/OR THROUGH. 27.12Z NAM/GFS SEEM TOO AGGRESSIVE BY CLEARING
THINGS OUT BY 21Z IN OUR WESTERN FORECAST AREA TODAY...WHICH IS
ALREADY TOO FAST PER LATEST SATELLITE IMAGERY. FOLLOWED MORE OF AN
IDEA PRESENTED BY THE RUC AND 925MB WIND FORECASTS...WHICH WOULD
SUGGEST CLEARING MAINLY OCCURRING AFTER MIDNIGHT TONIGHT INTO
MID-DAY MONDAY...WORKING FROM NORTHWEST TO SOUTHEAST AS 925MB WINDS
TURN SOUTHWESTERLY. IT IS POSSIBLE GRANT COUNTY STAYS CLOUDY ALL DAY
MONDAY WITH 925MB WINDS STILL FORECAST NEAR CALM OR OUT OF THE
NORTHEAST...SOMETHING THAT WILL HAVE TO BE MONITORED. OTHERWISE...
SHOULD GET A BAND OF MID/HIGH CLOUDS TO COME ACROSS MONDAY NIGHT
INTO TUESDAY WITH THE BRITISH COLUMBIA UPPER TROUGH. MORE HIGH
CLOUDS LOOK TO MOVE THROUGH WEDNESDAY AFTERNOON AS THE UPPER RIDGE
AXIS CROSSES THE FORECAST AREA.
TEMPERATURES ARE ALSO TRICKY. RAISED LOW TEMPERATURES UP FOR MOST
AREAS TONIGHT INTO THE MID TO UPPER 20S...EXCEPT FOR THE FAR WEST
WHERE CLEARING AND LIGHTER WINDS SHOULD ALLOW TEMPS TO TANK INTO THE
UPPER TEENS TO AROUND 20. STILL SHOULD SEE A DECENT AMOUNT OF SUN ON
MONDAY TO ALLOW TEMPS TO CLIMB INTO THE MID 30S TO LOW 40S...AIDED
BY 850MB TEMPS REACHING 4-6C BY LATE AFTERNOON AHEAD OF THE UPPER
TROUGH. LOOK FOR A COOL DOWN ON TUESDAY AS THE UPPER TROUGH
CROSSES...DROPPING 850MB TEMPS DOWN TO -2 TO -4C AND THUS HIGHS INTO
THE LOW TO MID 30S. TUESDAY NIGHT COULD BE QUITE CHILLY WITH A
SURFACE RIDGE CROSSING AND CLEAR SKIES. STAYED WITH A BLEND OF
GUIDANCE THEN. MODERATION IN TEMPERATURES IS EXPECTED AGAIN ON
WEDNESDAY WITH THE UPPER RIDGE COMING IN...BRINGING 850MB TEMPS UP
TO 1-3C.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
255 PM CST SUN NOV 27 2011
SIMILAR TO YESTERDAY...MODELS AND GFS ENSEMBLES ARE IN PRETTY GOOD
AGREEMENT THROUGH FRIDAY ON THE UPPER AIR PATTERN...THEN BEGIN TO
DIVERGE ON HOW TO HANDLE THE WEEKEND. FIRST FEATURE OF INTEREST IS A
LONG WAVE TROUGH EXTENDING FROM SASKATCHEWAN INTO CALIFORNIA AT 00Z
THURSDAY. MODELS PROG THIS TROUGH TO SPLIT INTO TWO...WITH THE
NORTHERN PORTION CROSSING THE FORECAST AREA THURSDAY NIGHT. AHEAD OF
THE TROUGH...MODELS HAVE BECOME IN BETTER AGREEMENT ALL SHOWING SOME
LIGHT SNOW COMING THROUGH...THOUGH FOR THE 27.12Z ECMWF IT IS A
CHANGE FROM ITS PREVIOUS RUN WHICH HAD NO SNOW DUE TO DRY LOW
LEVELS. THEREFORE...ONLY HAVE 20 PERCENT CHANCES OF SNOW AT THE
MOMENT. LATER FORECASTS MAY NEED HIGHER CHANCES IF MODELS STAY IN
AGREEMENT. DRY AND COLDER CONDITIONS LOOK ON TAP FOR THURSDAY NIGHT
INTO FRIDAY AS 850MB TEMPS DROP TO -8 TO -10C AND SURFACE HIGH
PRESSURE BUILDS IN. THE WEEKEND FEATURES ISSUES REGARDING HANDLING
SHORTWAVES DROPPING DOWN OFF A BUILDING EASTERN PACIFIC RIDGE...AND
IF THESE SHORTWAVES CAN POSSIBLY PHASE WITH THE SOUTHERN END OF THE
LONG WAVE TROUGH THAT GOT CUT-OFF ON THURSDAY. THE 27.12Z GFS AND
SOME OF ITS ENSEMBLES SAY THE CUT-OFF LOW REMAINS...RESULTING IN A
DRY NORTHWEST FLOW PATTERN FOR THE WEEKEND. THE 27.12Z ECMWF AND
EXTRAPOLATION OF THE 27.12Z UKMET/CANADIAN SUGGEST A PHASING OR AT
LEAST THE UPPER LOW GETTING KICKED NORTHEAST TOWARDS THE FORECAST
AREA. HARD TO SAY WHICH ONE IS RIGHT AT THIS MOMENT...BUT SINCE
VERIFICATION WISE THE ECMWF TENDS TO A LITTLE BETTER AND DOES HAVE
SOME CONSISTENCY FROM ITS PREVIOUS RUN...TEND TO LEAN MORE TOWARDS
THE ECMWF/UKMET/CANADIAN CAMP. UNDER THIS SCENARIO...SATURDAY SHOULD
STILL END UP DRY WITH MODERATION AS RETURN FLOW SETS UP BEHIND
FRIDAYS SURFACE RIDGE. ISENTROPIC LIFT/WARM ADVECTION THEN SET UP
FOR SATURDAY NIGHT ACROSS FAR SOUTHERN AREAS OF THE CWA...AND ACROSS
THE REST OF THE FORECAST AREA ON SUNDAY AS THE UPPER LOW APPROACHES.
PLACED IN 20 PERCENT CHANCES AT THE PRESENT TIME...GIVEN THE
UNCERTAINTY PRESENT WITH THE GFS SCENARIO AND SOME OF THE GFS
ENSEMBLES.
&&
.AVIATION...THROUGH 06Z TUESDAY
1136 PM CST SUN NOV 27 2011
CONCERN CONTINUES TO BE ON WHEN STRATUS DECK WILL CLEAR THE TAF
SITES. SATELLITE TRENDS THROUGHOUT THE EVENING INDICATE THE BACK
EDGE OF THE STRATUS DECK HAS BEEN SLOWLY PUSHING EASTWARD. ONCE
AGAIN MODELS NOT DEPICTING THE LOW LEVEL MOISTURE WELL AT ALL AND
THUS HAVE BASED CLEARING TREND BASED ON THE BACK EDGE
SPEED AND POSITION OF THE SURFACE RIDGE AND 925MB WINDS...WHICH IS
SIMILAR TO THE TIMING IN THE 00Z TAFS SO NO MAJOR CHANGES. ONCE
STRATUS CLEARS...VFR CONDITIONS WILL PREVAIL WITH ONLY A FEW
CLOUDS EXPECTED AFTER 00Z TUESDAY.
A COLD FRONT PUSHES THROUGH THE AREA AFTER MONDAY EVENING...WITH
THE WINDS BECOMING NORTHWESTERLY. THE PRESSURE GRADIENT DOES
TIGHTEN...AND EXPECT WINDS AT 12 KNOTS OR GREATER AFTER 04Z AT
KRST...WITH THE INCREASE AT KLSE AFTER 06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
255 PM CST SUN NOV 27 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1208 AM EST WED NOV 30 2011
.SYNOPSIS...
LOW PRESSURE WILL TRACK DOWN THE SAINT LAWRENCE RIVER VALLEY
OVERNIGHT...WITH AN ASSOCIATED OCCLUDED FRONT CROSSING THE TRI-STATE
AS A RESULT. THE LOW THEN CONTINUES TO MOVE DOWN THE SAINT
LAWRENCE RIVER VALLEY INTO WEDNESDAY NIGHT. HIGH PRESSURE BUILDS
IN THURSDAY AND FRIDAY. A WEAK COLD FRONT WILL MOVE ACROSS THE
REGION FRIDAY NIGHT INTO SATURDAY WITH HIGH PRESSURE BUILDING BACK
INTO THE REGION FROM LATE SATURDAY THROUGH MONDAY. LOW PRESSURE
THEN APPROACHES THE AREA MONDAY THROUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AT 2Z OCCLUDED FRONT WAS JUST INTO FAR WESTERN ZONES...AND MAKING VERY
SLOW PROGRESS EASTWARD...AS A RESULT HAVE SLOWED DOWN TIMING FOR THE END
OF THE STEADIER RAINFALL. WITH ALL LIGHTNING WITH THIS SYSTEM SO
FAR CONFINED TO MI TO THE NNW OF UPPER LOW AND WELL OFF NJ COAST -
SE OF BUOY 44066...HAVE GONE AHEAD AND REMOVED THUNDER FROM
FORECAST. BASICALLY EXPECT TO SEE PERIODS OF MODERATE RAIN THROUGH
MOST OF THE NIGHT...TAPERING OFF FROM W TO E TOWARDS MORNING.
WITH SLOWER FRONTAL TIMING...HAVE ADJUSTED TEMPERATURE FALL OFF
OVER THE REGION SLOWER...WITH A BLEND OF NAM 2-METER/HRRR
TEMPERATURES...AND THE LATEST GUIDANCE - MET/MAV/LAV. FOR NOW IT
APPEARS FRONT WILL MOVE THROUGH BEFORE MIDNIGHT...SO MAX MIN
RECORDS SHOULD BE SAFE. HAVE INCLUDED THEM IN THE CLIMATE SECTION
OF THE AFD IN CASE THE FRONT MOVES SLOWER THAN EXPECTED - GOING
FAIRLY CLOSE TO 18Z-NAM/23Z HRRR TIMING RIGHT NOW.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
CLOSED LOW SHEARS NE FROM THE EASTERN GREAT LAKES ON WED THROUGH THE
ST LAWRENCE RIVER VALLEY WED NIGHT.
AFTER ANY LINGERING SHRA OVER FAR EASTERN ZONES EARLY WEDNESDAY
MORNING...REGION WILL REMAIN IN DRY SLOT ON WED AS SHORTWAVE ENERGY
SHEARS NE WHILE SLIDING TO THE COAST. THIS SHOULD MAINTAIN
GENERALLY DRY CONDITIONS...WITH SCT-BKN INSTABILITY CU. AN
ISOLATED SHOWER/SPRINKLE IS POSSIBLE ACROSS FAR NW SECTIONS...BUT
NOT ENOUGH COVERAGE TO WARRANT POPS. TEMPS WILL FEEL MORE FALL
LIKE WITH GUSTY WSW WINDS AND CAA FLOW HOLDING TEMPS IN THE LOWER
50 INTERIOR...MID 50S COAST. THIS IS STILL A FEW DEGREES ABOVE
NORMAL THOUGH.
SHEARING SHORTWAVE ENERGY AND WEAK SURFACE TROUGH MOVE ACROSS THE
REGION WED NIGHT. AGAIN THIS SHOULD BE A MAINLY DRY PASSAGE...WITH
GRADUALLY CLEARING SKIES IN ITS WAKE. GUSTY NW WINDS WILL CONTINUE
TO DROP TEMPS TO NEAR SEASONABLE...UPPER 30S CITY/COAST...UPPER
20S/LOWER 30S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
PERIOD BEGINS WITH HIGH PRESSURE BUILDING IN FROM THE SOUTH AND
ZONAL FLOW ALOFT WITH LIGHT WINDS AND MOSTLY CLEAR SKIES.
TEMPERATURES WILL REMAIN NEAR NORMAL FOR THURSDAY AND FRIDAY. A
SHARP UPPER TROUGH SWEEPS THROUGH FRIDAY NIGHT WITH A WEAK COLD
FRONT. WITH DOWN SLOPING NORTHWEST WINDS AND LITTLE MOISTURE...NO
PRECIPITATION IS EXPECTED...JUST SOME MID LEVEL STRATO CU WITH THE
FRONT. A BRIEF SHOT OF COLD AIR WILL FOLLOW THIS FRONT WITH
TEMPERATURES SLIPPING A FEW DEGREES BELOW NORMAL ON SATURDAY.
HIGH PRESSURE BUILDS BACK IN FROM THE OHIO VALLEY THROUGH THE
WEEKEND WITH RIDGING ALOFT. TEMPERATURES RISE BACK TO NEAR NORMAL
SATURDAY AND SUNDAY WITH CIRRUS SPILLING OVER THE RIDGE.
NEXT POTENTIAL ISSUE WILL BE THE MON-WED TIME FRAME WITH GFS/ECMWF
BOTH HINTING AT A DEEP TROUGH DEVELOPING OVER THE MIDWEST AND A SFC
LOW DEVELOPING NEAR PA. BOTH SHOW PRECIPITATION IN THIS TIME FRAME
ASSOCIATED WITH THIS LOW PRESSURE AREA BUT KEPT POPS AT CHANCE
BECAUSE TIMING COULD CHANGE SIGNIFICANTLY IN THE NEXT FEW DAYS.
ECMWF THEN SHOWS THE UPPER LOW CUTTING OFF OVER NORTHERN NY AND A
SURFACE LOW DEEPENING OFF THE SOUTHERLY MAINE COAST WITH THE GFS
DEVELOPING THIS LOW MUCH FARTHER NORTH. DEPENDING ON THE EXACT TRACK
OF THIS SYSTEM...WINDS WILL PICK UP TUESDAY EVENING AND SNOW IS
POSSIBLE BEHIND THIS SYSTEM. TOO UNCERTAIN AT THIS POINT TO PUT MORE
THAN A CHANCE/SLIGHT CHANCE POPS FOR THIS SYSTEM.
TEMPS REMAIN NEAR NORMAL ON MONDAY AND DROP TO BELOW NORMAL ON
TUESDAY WITH LOWS NEAR TO BELOW FREEZING IN MOST AREAS TUESDAY NIGHT.
&&
.AVIATION /05Z WEDNESDAY THROUGH MONDAY/...
WINDS HAVE SHIFTED TO THE SOUTHWEST AS THE OCCLUDED FRONT CONTINUES
MOVING EAST OF CT AND LONG ISLAND. MOST CIGS AND VSBYS IMPROVED TO MVFR.
RAIN WILL END EAST OF NYC BETWEEN 06Z AND 08Z. MVFR CIGS AND VSBYS ARE
POSSIBLE DURING THIS TIME.
OTHERWISE...SW WINDS WILL RANGE FROM 15-20 KT WITH GUSTS OF 20-25 KT
AREA WIDE THROUGH THE DAY ON WEDNESDAY.
A WEAK COLD FRONT WILL CAUSE SW WINDS TO SHIFT TO THE NW AFTER SUNSET
WED AT SPEEDS BETWEEN 15 AND 20 KT AREA WIDE.
OUTLOOK FOR 00Z THURSDAY THROUGH MONDAY...
WED NIGHT: VFR. NW WINDS 15-20 KT WITH GUSTS 20-25 KT.
THU-MON...VFR.
&&
.MARINE...
SCA SE WINDS...WITH GUSTS UP TO 30 KT...EXPECTED AHEAD OF
OCCLUDED FRONT. SEAS EXPECTED TO CONTINUE BUILDING TO NEAR 7 TO
10 FT BY WEDNESDAY MORNING.
WINDS GRADUALLY SUBSIDE TO MARGINAL SCA BY WED MORNING AND CONTINUE
AS SUCH INTO WED NIGHT. OCEAN SEAS WILL ONLY SLOWLY SUBSIDE
THOUGH WITH THESE STRONG WINDS...LIKELY REMAINING SCA ON EASTERN
OCEAN WATERS...THROUGH WED NIGHT.
PERSISTENT WNW FLOW COULD MAINTAIN 5 FT SEAS INTO THURSDAY MORNING
WITH WINDS SUBSIDING AS HIGH PRESSURE BUILDS IN. WAVES WILL CONTINUE
TO DROP THROUGHOUT THE DAY THURSDAY AND REMAIN BELOW SCA CRITERIA.
WITH A COLD FRONT PASSAGE ON FRIDAY...SEAS ON THE EASTERN OCEAN
WATERS MAY PRODUCE SCA SEAS WHICH WILL LIKELY PERSIST THROUGH
SATURDAY. HIGH PRESSURE BUILDS IN ON SUNDAY WITH SEAS AND WINDS
BELOW SCA CRITERIA.
&&
.HYDROLOGY...
EXPECTING GENERALLY 1/2" TO 3/4" THROUGH TONIGHT...WITH LOCALLY
HIGHER AMOUNTS COINCIDENT WITH BANDING LOCATION. ONLY LOCALIZED
MINOR URBAN AND POOR DRAINAGE FLOODING EXPECTED.
&&
.CLIMATE...
RECORD HIGHEST MINIMUM TEMPERATURES (MAX MINS)
FOR TODAY - NOVEMBER 29TH
RECORD YEAR
CENTRAL PARK 58 2005
LAGUARDIA 60 2005
KENNEDY 56 2005
NEWARK 57 2005
ISLIP 57 2005
BRIDGEPORT 52 2005
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ330-
335-338-340-345-350-353-355.
&&
$$
SYNOPSIS...LN/NV
NEAR TERM...MALOIT
SHORT TERM...MALOIT/NV
LONG TERM...LN
AVIATION...GC
MARINE...MALOIT/LN/NV
HYDROLOGY...NV
CLIMATE...
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
310 AM EST Wed Nov 30 2011
.SYNOPSIS...
07Z water vapor and H4 RUC analysis shows an active upper level
pattern across the CONUS this morning. Large upper level low that
has been influencing our weather the past few days is now quickly
lifting out to the northeast and taking its mid-level cold pool with
it. On the backside of this upper low, a shortwave impulse is
dropping southeastward over the middle MS valley/Southern Plains.
This impulse will amplify as it slide along the northern Gulf coast
during the next 24 hours, and although it looks impressive later
today on forecast upper level charts, the atmosphere will simply be
too dry for this energy to have any significant impact on our
sensible weather. Finally, looking far to the west we find a potent
upper level trough arriving over the Pacific Northwest coast. This
energy is progged by global guidance to cut off and stall as it
reaches the southern California coast.
Low levels/surface,
1025mb high pressure is centered over the southern Plains this
morning. An extension of this ridge reaches eastward all the way to
our forecast area. Vast area of lower stratus under the residual
cold pool from the departing upper low covers much of AL/GA and into
the FL panhandle this morning. These clouds combined with a bit of
wind are helping to keep temps up generally in the 40s. Locations
ahead of this band of clouds from KVLD south into the eastern FL big
bend will likely be able to drop into the mid/upper 30s before
sunrise.
&&
.SHORT TERM (Today through Friday)...
Today,
Surface high pressure will move east from the Southern Plains toward
the region. At the same time, shortwave energy aloft will approach
and slide over the region by this evening. Main forecast concern
this morning will be the evolution/dissipation of the stratus deck
over portions of the area. The retreat of the cold pool aloft should
promote the dissipation of this cloud deck through the morning
hours. 00Z NAM and 06Z local hi-res WRF-ARW are handling the initial
position of these clouds best, and will follow a blend of these
models for morning movement and timing of dissipation in the grids.
Both models show rapid dissipation of this deck after 15Z...and will
remove all low level stratus over the landmass by early afternoon.
Amplifying mid/upper level shortwave and associated jet streak will
overspread the area later today. Decent zone of synoptic support/QG
forcing head of the shortwave along with associated jet dynamics may
bring a few bands of upper level cirrus overhead during the
afternoon/evening...however these should be thin and will keep a
mostly sunny forecast for the afternoon hours. The lower/mid levels
will be very dry as well by this afternoon...and despite the
overspread synoptic lift, rain chances will be near zero.
Temperatures will be quite cool once again as the near solar
minimum keep diurnal mixing on the weak side. Generally looking for
high temps in the middle 50s to perhaps around 60 degrees.
Tonight,
A cold night in store. Freeze watches are being hoisted for all
zones during the late night/early morning hours of Thursday.
Shortwave and any associated upper level cirrus will be exiting to
our east by later this evening allow for clear skies. Surface high
is not in an ideal position, but feel it will be close enough to
allow areas of boundary layer decoupling late tonight. Once this
decoupling allows winds to go calm, these light winds combined with
the very dry low levels will create excellent radiational cooling
conditions, and temperatures will drop quickly. Currently expecting
many locations away from the immediate coast, and away from more
urbanized areas to reach or drop a few degrees below freezing.
Normally colder sheltered/inland spots may briefly reach the upper
20s by sunrise. Once again...locations along the immediate coast and
in urbanized spots (such as downtown Tallahassee) are likely to
remain a few degrees above freezing. However, even for these
locations, temps reaching the middle 30s will still support frost
development.
Thursday through Friday,
Stacked ridging will bring pleasant, dry, and seasonable conditions
to the region through the end of the work week. The daylight hours
of Thursday will feature plenty of sunshine and temperatures rising
from the cold early morning readings toward the lower/mid 60s by mid
afternoon. Thursday night will again be cool, but currently not
anticipating any widespread freezing temperatures. As the ridge
center to our north begins to move eastward, low level flow will
come around more to the NE/E and begin to transport a slow increase
in Atlantic moisture toward the region. With this in mind, the best
chances of seeing temps approach 32 Thursday night will be across
our northern/western zones. Friday is shaping up to be quite a
pleasant day, with plenty of sunshine and temperatures up another
several degrees from Thursday.
&&
.LONG TERM (Saturday through next Wednesday)...
The extended period will begin with an amplified upper pattern
across the CONUS, consisting of a deep trough and cut-off low over
the four corners region, and a building ridge stretching from the
Gulf of Mexico up the eastern seaboard. The system over the
southwestern states will slowly progress eastward through the period
and bring a front into the deep south by late Monday into Tuesday,
ushering in a shot of cold air for the middle of next week.
Ahead of this system, dry conditions and moderating temperatures are
expected across the forecast area, with easterly flow on Saturday,
becoming onshore by late Sunday into Monday. Temperatures are
forecast to be at, or just slightly above, normal through the
weekend.
A band of showers is expected to accompany the front into the region
beginning Monday and continuing through Monday night. At this time,
it appears the main energy with the system will be shunted northward
by the pre-existing upper ridge, causing the rain to diminish as the
front crosses the forecast area. Instability is forecast to be
minimal or non-existent with no thunderstorms expected.
&&
.MARINE...
Offshore flow will continue through today on the eastern periphery
of approaching surface high pressure. Although winds are now
generally below advisory levels, seas have been slow to subside over
the offshore waters and will extend the advisory for these legs
through the morning hours. Surface high pressure will slowly pass to
our north through the end of the week allowing winds to come around
to the Northeast and eventually east. With the easterly flow,
periods of cautionary conditions are likely to develop each
overnight period. The next front is not expected to approach the
forecast waters until the early portion of next week.
&&
.AVIATION (Through 06Z Wednesday)...Large area of MVFR CIGS is
continuing to impact area terminals this morning (primarily KVLD,
KECP, and KABY). These clouds should break up and dissipate
shortly after sunrise this morning with VFR conditions prevailing
thereafter.
&&
.FIRE WEATHER...
A cool and dry airmass will be in place across the region through
the next two days. However, relative humidity values are forecast to
remain just above critical values. Therefore, no Red Flag conditions
are expected attm.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 58 31 64 36 70 / 0 0 0 0 0
Panama City 58 35 62 44 68 / 0 0 0 0 0
Dothan 57 31 62 36 66 / 0 0 0 0 0
Albany 57 30 63 33 68 / 0 0 0 0 0
Valdosta 58 32 64 35 69 / 0 0 0 0 0
Cross City 61 32 68 38 72 / 0 0 0 0 0
Apalachicola 59 36 62 44 66 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Freeze Watch from late tonight through Thursday morning for
Coffee-Dale-Geneva-Henry-Houston.
GA...Freeze Watch from late tonight through Thursday morning for
Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-
Decatur-Dougherty-Early-Grady-Irwin-Lanier-Lee-Lowndes-
Miller-Mitchell-Quitman-Randolph-Seminole-Terrell-Thomas-
Tift-Turner-Worth.
FL...Freeze Watch from late tonight through Thursday morning for
Calhoun-Central Walton-Coastal Bay-Coastal Dixie-Coastal
Franklin-Coastal Gulf-Coastal Jefferson-Coastal Taylor-
Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland Dixie-
Inland Franklin-Inland Gulf-Inland Jefferson-Inland Taylor-
Inland Wakulla-Inland Walton-Jackson-Lafayette-Leon-Liberty-
Madison-South Walton-Washington.
GM...Small Craft Advisory until 11 AM EST this morning for Waters
from Suwannee River to Apalachicola FL from 20 to 60 NM-
Waters from Apalachicola to Destin FL from 20 to 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...CAMP
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
157 AM CST WED NOV 30 2011
.DISCUSSION...
840 PM CST
HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST THIS EVENING TO TWEAK
FOR CURRENT TRENDS. WINDS CONTINUE TO DIMINISH ACROSS ILLINOIS AS
THE TIGHTER PRESSURE GRADIENT SHIFTS TO THE EAST AS THE LOW MOVES
OVER LAKE ERIE. WIND DIRECTION HAS SHIFTED SLIGHTLY WEST OF NORTH
WHICH HAS ALLOWED MORE OF AN OFFSHORE WIND TO SET UP ALONG THE
ILLINOIS SHORE RESULTING IN WINDS FALLING BELOW ADVISORY CRITERIA.
WINDS OVER THE WATER REMAIN STRONG WITH GUSTS INTO THE 35-45 KT
RANGE WHICH CONTINUE TO MOVE ONSHORE ACROSS NORTHWEST INDIANA.
SOME GUSTS TO 35-40 KT MAY ALSO BE AFFECTING THE FAR SOUTHERN COOK
COUNTY LAKESHORE BUT THIS SHOULD BE INFREQUENT. FORECAST SOUNDINGS
SHOW THAT WINDS OFF THE DECK WILL QUICKLY DIMINISH ACROSS NW
INDIANA TO THE POINT WHERE ADVISORY LEVEL SPEEDS WOULD NOT BE
SUPPORTED TOWARDS 06-07Z. GIVEN THIS AND THE STRONGER WINDS
CONTINUING ACROSS LAKE AND PORTER COUNTY INDIANA AT THIS HOUR HAVE
EXTENDED THE WIND ADVISORY UNTIL 07Z. OTHERWISE SKIES CONTINUE TO
CLEAR FROM THE WEST ALLOWING TEMPS JUST WEST OF THE CWA TO FALL
INTO THE UPPER 20S WITH SIMILAR READINGS NOT FAR BEHIND FOR THE
WESTERN CWA. GOING FORECAST LOWS STILL LOOK ON TRACK.
MDB
//PREV DISCUSSION...
313 PM CST
MESOSCALE/TONIGHT...
A VERY IMPRESSIVE WATER VAPOR SATELLITE LOOP THIS AFTERNOON
REVEALS THE EXPANSIVE COLD CORE LOW LIFTING NORTHEAST ACROSS THE
APPALACHIANS...JUST GRAZING THE AREA. A WELL-DEFINED DEFORMATION
AREA HAS FILLED IN WITH BANDS OF COLDER AND AT TIMES CONVECTIVE
CLOUD TOPS PROVIDING HEAVIER AND FROZEN PRECIPITATION ACROSS PARTS
OF NORTHERN IN. THE DUAL POLARIZATION RADAR EVEN DETECTED THE
PRECIPITATION TYPE SWITCH AT 7000-9000 FT. THIS HAS BEEN OBSERVED
AT THE GROUND JUST TO THE SOUTH AND EAST OF THE FORECAST AREA IN
LAFAYETTE /WHERE SLUSHY ACCUMULATION HAS OCCURRED ON GRASSY
SURFACES/. THE 13KM RUC SOUNDINGS ACROSS BENTON AND JASPER
COUNTIES CONTINUE TO SHOW A GRADUAL SHRINKING OF THE NEAR-SURFACE
WARM LAYER TO ALLOW FOR A MIX TO MAKE IT TO THE GROUND FOR
POSSIBLY A COUPLE HOURS. THAT COUPLE OF HOURS LOOKS TO BE IT GIVEN
SATELLITE AND SHORT TERM MODEL TRENDS TO SHIFT THE FORCING EAST.
GIVEN THAT ANY TRANSITION WILL BE SO SHORT LIVED AND OVER WARM
GROUND...WILL CANCEL THE WINTER WEATHER ADVISORY.
STRONG NORTHERLY WINDS HAVING GUSTED AS HIGH AS 60 MPH AT THE
CHICAGO CRIB...52 MPH AT GARY...AND 48 MPH AT MIDWAY WILL
GRADUALLY DIMINISH THROUGH THE EVENING WITH THE AREA PINCHED
BETWEEN THE 1001 MB LOW NEAR CLEVELAND AND THE INCOMING 1027 MB
RIDGE. AN AIRCRAFT SOUNDING OUT OF OHARE JUST AFTER 2 PM REVEALED
40 KT WINDS AT THE TOP OF THE CHANNEL...AND NAM AND RUC SOUNDINGS
KEEP SIMILAR SPEEDS WITHIN THE BOUNDARY LAYER UNTIL A COUPLE HOURS
AFTER SUNSET. WITH STILL AN ONSHORE COMPONENT TO THE WIND...WILL
LET THE WIND ADVISORY CONTINUE. A QUICK DECOUPLING LATER IN THE
EVENING SHOULD ALLOW FOR WINDS TO COME DOWN MORE RAPIDLY ACROSS
THE ILLINOIS FORECAST AREA. ASSOCIATED LAKE SHORE FLOODING
CONCERNS WITH THE WIND ALSO CONTINUE GIVEN THE 10 TO 15 FT WAVES
FORECAST...BUT LIKELY WILL NOT LAST AS FAR INTO WEDNESDAY. CLOUDS
SHOULD SCOUR FAIRLY QUICKLY WEST OF CHICAGO THROUGH EARLY
EVENING...THEN MORE SLOWLY DOWNSTREAM OF THE LAKE. WHILE SOME LAKE
ENHANCED CLOUDS MAY OCCUR...FORECAST DEPTHS ARE VERY SHALLOW WITH
DRIER AIR BEING RAKED IN ON THE NORTHERLY WINDS...AND THUS NOT
EXPECTING ANY SHOWERS. WITH FORECAST TEMPERATURES HAVE MADE ONLY
MINOR TWEAKS...WITH READINGS ALMOST RIGHT AT NORMAL ACROSS THE
ENTIRE FORECAST AREA.
MTF
WEDNESDAY THROUGH TUESDAY...
ACTUALLY LOOKING LIKE A DAY OR TWO OF FAIRLY PLEASANT LATE NOVEMBER
WEATHER WEDNESDAY INTO THURSDAY IN WAKE OF TODAY`S SIDESWIPING BY
THE STRONG STORM SYSTEM. WARM AIR ADVECTION WILL COMMENCE WEDNESDAY
AS LOW/MID LEVEL FLOW BEGINS TO BACK IN ADVANCE OF THE NEXT NORTHERN
STREAM SHORTWAVE WHICH WILL BEGIN DROPPING INTO THE NORTHERN PLAINS.
AFTER A CHILLY MORNING TEMPS SHOULD REBOUND NICELY TOMORROW WITH
NEARLY FULL SUNSHINE.
INCREASING MID/HIGH LEVEL CLOUDINESS AND SOUTHWEST WINDS SHOULD KEEP
TEMPS A BIT WARMER TOMORROW NIGHT WHICH WILL THEN PROVIDE FOR A NICE
SPRING BOARD FOR TEMPS THURSDAY TO CLIMB BACK TO SEVERAL DEGREES
ABOVE AVERAGE. COLD FRONT WILL THEN DROP SOUTHWARD ACROSS THE CWA
LATE THURSDAY AFTERNOON/EARLY THURSDAY EVENING. STRONGEST FORCING
WITH THIS WAVE LOOKS TO PASS WELL NORTH/NORTHEAST OF THE AREA AND
WITH SCANT MOISTURE AT BEST AM HAVING A HARD TIME GETTING TOO WORKED
UP OVER OUR SNOW CHANCES THURSDAY NIGHT. ECMWF/GFS BOTH STILL TRYING
TO SPIT OUT A HUNDREDTH OF AN INCH OR SO OF QPF SO HAVE MAINTAINED
THE SLIGHT CHANCE POPS WE HAD GOING...WHICH ARE SUPPORTED BY CURRENT
MOS NUMBERS.
VERY QUICK HITTING SHOT OF FAIRLY COLD AIR THEN ARRIVES LATER
THURSDAY NIGHT AND ESPECIALLY FRIDAY. THERE STILL DOES APPEAR TO BE
A SMALL WINDOW OF OPPORTUNITY FOR SOME LAKE EFFECT SNOW SHOWERS IN
PORTER COUNTY LATE THURSDAY NIGHT INTO FRIDAY MORNING...BUT NOT
EXPECTING ANYTHING SIGNIFICANT WITH LAKE EFFECT PARAMETERS FAIRLY
MARGINAL AND DURATION BEING SHORT AS FLOW QUICKLY BACKS TO
SOUTHERLY FRIDAY AFTERNOON.
BY THIS WEEKEND OUR ATTENTION WILL TURN THE THE VIGOROUS UPPER LOW
THATS CURRENTLY OFF THE BRITISH COLUMBIA COAST. MEDIUM RANGE
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT THROUGH FRIDAY WITH THIS
SYSTEM DROPPING SOUTH AND WITH AN ANOMALOUSLY STRONG UPPER LOW (H5
HEIGHTS 3+ STANDARD DEVIATIONS BELOW AVERAGE) SETTING UP SHOP OVER
THE DESSERT SOUTHWEST BY FRIDAY. MODERATE RIDGING DOWNSTREAM OVER
THE SOUTHEASTERN CONUS SHOULD LEAVE OUR AREA IN A WEST-SOUTHWEST
FLOW ALOFT.
FORECAST CONFIDENCE THIS WEEKEND INTO EARLY NEXT WEEK IS LOW AS
MODELS OFTEN STRUGGLE WITH CUT OFF LOWS. HAVING SAID THAT...IT
APPEARS AS THOUGH THIS FIRST UPPER LOW WILL WEAKEN INTO AN OPEN WAVE
AND RIDE THE SOUTHWEST FLOW ALOFT INTO OUR AREA THIS WEEKEND...WITH
SOME DEGREE OF PHASING WITH A RESULTANT AMPLIFYING NORTHERN
STREAM TROUGH EXPECTED. WHILE DETAILS ARE MURKY...IT WOULD APPEAR
THAT OUR AREA IS IN STORE FOR INCREASINGLY UNSETTLED WEATHER LATE
SATURDAY INTO SUNDAY. WITH VARYING SOLUTIONS ABOUT THE TRACK OF
THE SURFACE SYSTEM AND RESULTANT THERMAL PROFILES IT WOULD BE
ABSURD TRYING TO PINPOINT P-TYPES FOR THE WEEKEND JUST YET.
ANOTHER...POTENTIALLY MORE SIGNIFICANT BUT BRIEF BLAST OF COLD AIR
LOOKS TO ARRIVE IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* NONE
KJB
//DISCUSSION...UPDATED 06Z...
WINDS CONTINUE TO TAPER OFF THIS EVENING AS A STRONG LOW PRESSURE
SYSTEM MOVES OUT OF THE REGION. SURFACE PRESSURE GRADIENT
CONTINUES TO RELAX AND MOST GUSTS ACROSS THE REGION HAVE
ENDED...WITH THE EXCEPTION OF THE EASTERN TERMINALS...ORD/MDW
OCCNLY GUST TO 20 KT...AND THAT SHOULD LIKELY CONTINUE FOR A FEW
MORE HOURS BEFORE COMPLETELY STOPPING. GYY WILL CONTINUE TO GUST
STRONGER IN THE 35 KT RANGE OUT THE GATE. THOSE WINDS SHOULD
SLOWLY ABATE OVERNIGHT AS HIGH PRESSURE SWINGS IN FROM THE PLAINS
AND FLIPS FLOW NW...W...AND EVENTUALLY AROUND TO THE SW. CIGS WILL
CONTINUE TO CLEAR FROM W TO E TONIGHT...WITH THE WESTERN FLANK OF
CLOUDS THAT ARE OVERHEAD AND SHIFT EAST...STRETCHING FROM JUST
EAST OF JVL TO ARR AND SOUTH TO IKK. GENERALLY CLEAR SKIES AND
LIGHT WINDS ANTICIPATED FOR THE PRESENT TAFOR.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY...VFR...CHC -SN...MVFR LATE
* FRIDAY...VFR
* SATURDAY...SLT CHC RA...RASN...MVFR POSSIBLE
* SUNDAY...CHC SN...MVFR POSSIBLE
* MONDAY...VFR
SHEA
&&
.MARINE...
153 PM...LOW PRESSURE NEAR LAKE ERIE WILL CONTINUE TO LIFT
NORTHEAST TONIGHT AND INTO QUEBEC WEDNESDAY MORNING WHILE A LARGE
RIDGE OF HIGH PRESSURE EXTENDS FROM JAMES BAY SOUTHWEST INTO THE
CENTRAL PLAINS. THE GRADIENT BETWEEN THESE TWO FEATURES WILL
REMAIN STRONG BUT SLOWLY WEAKEN TONIGHT. SPEEDS/GUSTS PEAKED MID
MORNING AND EXPECT GALES IN THE 40-45 KT RANGE FOR MUCH OF THE
EVENING...BUT THREAT FOR STORM FORCE GUSTS TO 50 KT APPEARS TO
HAVE ENDED.
THE RIDGE NOTED ABOVE WILL SPLIT TONIGHT AS ONE AREA MOVES EAST
ACROSS NORTHERN QUEBEC AND THE SOUTHERN AREA DROPS SOUTH ACROSS THE
SOUTHERN PLAINS AND OHIO VALLEY WEDNESDAY. THE NORTHERN PORTION OF
THIS RIDGE WILL MOVE ACROSS LAKE MICHIGAN WEDNESDAY AFTERNOON WITH
WIND SPEEDS RAPIDLY DIMINISHING WEDNESDAY MORNING AND BECOMING
SOUTHWEST BY EVENING.
A WEAK LOW WILL DEVELOP OVER THE PLAINS WEDNESDAY NIGHT AND QUICKLY
MOVE ACROSS THE NORTHERN LAKES REGION THURSDAY AFTERNOON...
DRAGGING A COLD FRONT ACROSS THE LAKE THURSDAY NIGHT. THE GRADIENT
TIGHTENS BEHIND THIS FRONT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE PLAINS. BUT IN ADDITION TO THE TIGHTENING GRADIENT...COLDER
AIR WILL ALSO BE SPREADING ACROSS THE REGION AND EXPECT NORTHERLY
WINDS GUSTING TO AT LEAST 30 KTS WITH THE POTENTIAL FOR SOME GUSTS
TO 35 KTS. THIS HIGH THEN QUICKLY MOVES EAST ON FRIDAY WITH
SOUTHERLY WINDS DEVELOPING OVER THE LAKE FRIDAY NIGHT AS LOW
PRESSURE LIFTS NORTH ACROSS CANADA. ANOTHER COLD FRONT THEN MOVES
ACROSS THE LAKES REGION SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ014 UNTIL 2 AM WEDNESDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 5 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-LMZ874-
LMZ876-LMZ878 UNTIL 5 AM WEDNESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL NOON WEDNESDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 2 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1051 PM CST TUE NOV 29 2011
.DISCUSSION...
840 PM CST
HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST THIS EVENING TO TWEAK
FOR CURRENT TRENDS. WINDS CONTINUE TO DIMINISH ACROSS ILLINOIS AS
THE TIGHTER PRESSURE GRADIENT SHIFTS TO THE EAST AS THE LOW MOVES
OVER LAKE ERIE. WIND DIRECTION HAS SHIFTED SLIGHTLY WEST OF NORTH
WHICH HAS ALLOWED MORE OF AN OFFSHORE WIND TO SET UP ALONG THE
ILLINOIS SHORE RESULTING IN WINDS FALLING BELOW ADVISORY CRITERIA.
WINDS OVER THE WATER REMAIN STRONG WITH GUSTS INTO THE 35-45 KT
RANGE WHICH CONTINUE TO MOVE ONSHORE ACROSS NORTHWEST INDIANA.
SOME GUSTS TO 35-40 KT MAY ALSO BE AFFECTING THE FAR SOUTHERN COOK
COUNTY LAKESHORE BUT THIS SHOULD BE INFREQUENT. FORECAST SOUNDINGS
SHOW THAT WINDS OFF THE DECK WILL QUICKLY DIMINISH ACROSS NW
INDIANA TO THE POINT WHERE ADVISORY LEVEL SPEEDS WOULD NOT BE
SUPPORTED TOWARDS 06-07Z. GIVEN THIS AND THE STRONGER WINDS
CONTINUING ACROSS LAKE AND PORTER COUNTY INDIANA AT THIS HOUR HAVE
EXTENDED THE WIND ADVISORY UNTIL 07Z. OTHERWISE SKIES CONTINUE TO
CLEAR FROM THE WEST ALLOWING TEMPS JUST WEST OF THE CWA TO FALL
INTO THE UPPER 20S WITH SIMILAR READINGS NOT FAR BEHIND FOR THE
WESTERN CWA. GOING FORECAST LOWS STILL LOOK ON TRACK.
MDB
//PREV DISCUSSION...
313 PM CST
MESOSCALE/TONIGHT...
A VERY IMPRESSIVE WATER VAPOR SATELLITE LOOP THIS AFTERNOON
REVEALS THE EXPANSIVE COLD CORE LOW LIFTING NORTHEAST ACROSS THE
APPALACHIANS...JUST GRAZING THE AREA. A WELL-DEFINED DEFORMATION
AREA HAS FILLED IN WITH BANDS OF COLDER AND AT TIMES CONVECTIVE
CLOUD TOPS PROVIDING HEAVIER AND FROZEN PRECIPITATION ACROSS PARTS
OF NORTHERN IN. THE DUAL POLARIZATION RADAR EVEN DETECTED THE
PRECIPITATION TYPE SWITCH AT 7000-9000 FT. THIS HAS BEEN OBSERVED
AT THE GROUND JUST TO THE SOUTH AND EAST OF THE FORECAST AREA IN
LAFAYETTE /WHERE SLUSHY ACCUMULATION HAS OCCURRED ON GRASSY
SURFACES/. THE 13KM RUC SOUNDINGS ACROSS BENTON AND JASPER
COUNTIES CONTINUE TO SHOW A GRADUAL SHRINKING OF THE NEAR-SURFACE
WARM LAYER TO ALLOW FOR A MIX TO MAKE IT TO THE GROUND FOR
POSSIBLY A COUPLE HOURS. THAT COUPLE OF HOURS LOOKS TO BE IT GIVEN
SATELLITE AND SHORT TERM MODEL TRENDS TO SHIFT THE FORCING EAST.
GIVEN THAT ANY TRANSITION WILL BE SO SHORT LIVED AND OVER WARM
GROUND...WILL CANCEL THE WINTER WEATHER ADVISORY.
STRONG NORTHERLY WINDS HAVING GUSTED AS HIGH AS 60 MPH AT THE
CHICAGO CRIB...52 MPH AT GARY...AND 48 MPH AT MIDWAY WILL
GRADUALLY DIMINISH THROUGH THE EVENING WITH THE AREA PINCHED
BETWEEN THE 1001 MB LOW NEAR CLEVELAND AND THE INCOMING 1027 MB
RIDGE. AN AIRCRAFT SOUNDING OUT OF OHARE JUST AFTER 2 PM REVEALED
40 KT WINDS AT THE TOP OF THE CHANNEL...AND NAM AND RUC SOUNDINGS
KEEP SIMILAR SPEEDS WITHIN THE BOUNDARY LAYER UNTIL A COUPLE HOURS
AFTER SUNSET. WITH STILL AN ONSHORE COMPONENT TO THE WIND...WILL
LET THE WIND ADVISORY CONTINUE. A QUICK DECOUPLING LATER IN THE
EVENING SHOULD ALLOW FOR WINDS TO COME DOWN MORE RAPIDLY ACROSS
THE ILLINOIS FORECAST AREA. ASSOCIATED LAKE SHORE FLOODING
CONCERNS WITH THE WIND ALSO CONTINUE GIVEN THE 10 TO 15 FT WAVES
FORECAST...BUT LIKELY WILL NOT LAST AS FAR INTO WEDNESDAY. CLOUDS
SHOULD SCOUR FAIRLY QUICKLY WEST OF CHICAGO THROUGH EARLY
EVENING...THEN MORE SLOWLY DOWNSTREAM OF THE LAKE. WHILE SOME LAKE
ENHANCED CLOUDS MAY OCCUR...FORECAST DEPTHS ARE VERY SHALLOW WITH
DRIER AIR BEING RAKED IN ON THE NORTHERLY WINDS...AND THUS NOT
EXPECTING ANY SHOWERS. WITH FORECAST TEMPERATURES HAVE MADE ONLY
MINOR TWEAKS...WITH READINGS ALMOST RIGHT AT NORMAL ACROSS THE
ENTIRE FORECAST AREA.
MTF
WEDNESDAY THROUGH TUESDAY...
ACTUALLY LOOKING LIKE A DAY OR TWO OF FAIRLY PLEASANT LATE NOVEMBER
WEATHER WEDNESDAY INTO THURSDAY IN WAKE OF TODAY`S SIDESWIPING BY
THE STRONG STORM SYSTEM. WARM AIR ADVECTION WILL COMMENCE WEDNESDAY
AS LOW/MID LEVEL FLOW BEGINS TO BACK IN ADVANCE OF THE NEXT NORTHERN
STREAM SHORTWAVE WHICH WILL BEGIN DROPPING INTO THE NORTHERN PLAINS.
AFTER A CHILLY MORNING TEMPS SHOULD REBOUND NICELY TOMORROW WITH
NEARLY FULL SUNSHINE.
INCREASING MID/HIGH LEVEL CLOUDINESS AND SOUTHWEST WINDS SHOULD KEEP
TEMPS A BIT WARMER TOMORROW NIGHT WHICH WILL THEN PROVIDE FOR A NICE
SPRING BOARD FOR TEMPS THURSDAY TO CLIMB BACK TO SEVERAL DEGREES
ABOVE AVERAGE. COLD FRONT WILL THEN DROP SOUTHWARD ACROSS THE CWA
LATE THURSDAY AFTERNOON/EARLY THURSDAY EVENING. STRONGEST FORCING
WITH THIS WAVE LOOKS TO PASS WELL NORTH/NORTHEAST OF THE AREA AND
WITH SCANT MOISTURE AT BEST AM HAVING A HARD TIME GETTING TOO WORKED
UP OVER OUR SNOW CHANCES THURSDAY NIGHT. ECMWF/GFS BOTH STILL TRYING
TO SPIT OUT A HUNDREDTH OF AN INCH OR SO OF QPF SO HAVE MAINTAINED
THE SLIGHT CHANCE POPS WE HAD GOING...WHICH ARE SUPPORTED BY CURRENT
MOS NUMBERS.
VERY QUICK HITTING SHOT OF FAIRLY COLD AIR THEN ARRIVES LATER
THURSDAY NIGHT AND ESPECIALLY FRIDAY. THERE STILL DOES APPEAR TO BE
A SMALL WINDOW OF OPPORTUNITY FOR SOME LAKE EFFECT SNOW SHOWERS IN
PORTER COUNTY LATE THURSDAY NIGHT INTO FRIDAY MORNING...BUT NOT
EXPECTING ANYTHING SIGNIFICANT WITH LAKE EFFECT PARAMETERS FAIRLY
MARGINAL AND DURATION BEING SHORT AS FLOW QUICKLY BACKS TO
SOUTHERLY FRIDAY AFTERNOON.
BY THIS WEEKEND OUR ATTENTION WILL TURN THE THE VIGOROUS UPPER LOW
THATS CURRENTLY OFF THE BRITISH COLUMBIA COAST. MEDIUM RANGE
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT THROUGH FRIDAY WITH THIS
SYSTEM DROPPING SOUTH AND WITH AN ANOMALOUSLY STRONG UPPER LOW (H5
HEIGHTS 3+ STANDARD DEVIATIONS BELOW AVERAGE) SETTING UP SHOP OVER
THE DESSERT SOUTHWEST BY FRIDAY. MODERATE RIDGING DOWNSTREAM OVER
THE SOUTHEASTERN CONUS SHOULD LEAVE OUR AREA IN A WEST-SOUTHWEST
FLOW ALOFT.
FORECAST CONFIDENCE THIS WEEKEND INTO EARLY NEXT WEEK IS LOW AS
MODELS OFTEN STRUGGLE WITH CUT OFF LOWS. HAVING SAID THAT...IT
APPEARS AS THOUGH THIS FIRST UPPER LOW WILL WEAKEN INTO AN OPEN WAVE
AND RIDE THE SOUTHWEST FLOW ALOFT INTO OUR AREA THIS WEEKEND...WITH
SOME DEGREE OF PHASING WITH A RESULTANT AMPLIFYING NORTHERN
STREAM TROUGH EXPECTED. WHILE DETAILS ARE MURKY...IT WOULD APPEAR
THAT OUR AREA IS IN STORE FOR INCREASINGLY UNSETTLED WEATHER LATE
SATURDAY INTO SUNDAY. WITH VARYING SOLUTIONS ABOUT THE TRACK OF
THE SURFACE SYSTEM AND RESULTANT THERMAL PROFILES IT WOULD BE
ABSURD TRYING TO PINPOINT P-TYPES FOR THE WEEKEND JUST YET.
ANOTHER...POTENTIALLY MORE SIGNIFICANT BUT BRIEF BLAST OF COLD AIR
LOOKS TO ARRIVE IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NO CONCERNS OVERNIGHT
SHEA
//DISCUSSION...UPDATED 06Z...
WINDS CONTINUE TO TAPER OFF THIS EVENING AS A STRONG LOW PRESSURE
SYSTEM MOVES OUT OF THE REGION. SURFACE PRESSURE GRADIENT
CONTINUES TO RELAX AND MOST GUSTS ACROSS THE REGION HAVE
ENDED...WITH THE EXCEPTION OF THE EASTERN TERMINALS...ORD/MDW
OCCNLY GUST TO 20 KT...AND THAT SHOULD LIKELY CONTINUE FOR A FEW
MORE HOURS BEFORE COMPLETELY STOPPING. GYY WILL CONTINUE TO GUST
STRONGER IN THE 35 KT RANGE OUT THE GATE. THOSE WINDS SHOULD
SLOWLY ABATE OVERNIGHT AS HIGH PRESSURE SWINGS IN FROM THE PLAINS
AND FLIPS FLOW NW...W...AND EVENTUALLY AROUND TO THE SW. CIGS WILL
CONTINUE TO CLEAR FROM W TO E TONIGHT...WITH THE WESTERN FLANK OF
CLOUDS THAT ARE OVERHEAD AND SHIFT EAST...STRETCHING FROM JUST
EAST OF JVL TO ARR AND SOUTH TO IKK. GENERALLY CLEAR SKIES AND
LIGHT WINDS ANTICIPATED FOR THE PRESENT TAFOR.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
SHEA
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY...VFR...CHC -SN...MVFR LATE
* FRIDAY...VFR
* SATURDAY...SLT CHC RA...RASN...MVFR POSSIBLE
* SUNDAY...CHC SN...MVFR POSSIBLE
* MONDAY...VFR
SHEA
&&
.MARINE...
153 PM...LOW PRESSURE NEAR LAKE ERIE WILL CONTINUE TO LIFT
NORTHEAST TONIGHT AND INTO QUEBEC WEDNESDAY MORNING WHILE A LARGE
RIDGE OF HIGH PRESSURE EXTENDS FROM JAMES BAY SOUTHWEST INTO THE
CENTRAL PLAINS. THE GRADIENT BETWEEN THESE TWO FEATURES WILL
REMAIN STRONG BUT SLOWLY WEAKEN TONIGHT. SPEEDS/GUSTS PEAKED MID
MORNING AND EXPECT GALES IN THE 40-45 KT RANGE FOR MUCH OF THE
EVENING...BUT THREAT FOR STORM FORCE GUSTS TO 50 KT APPEARS TO
HAVE ENDED.
THE RIDGE NOTED ABOVE WILL SPLIT TONIGHT AS ONE AREA MOVES EAST
ACROSS NORTHERN QUEBEC AND THE SOUTHERN AREA DROPS SOUTH ACROSS THE
SOUTHERN PLAINS AND OHIO VALLEY WEDNESDAY. THE NORTHERN PORTION OF
THIS RIDGE WILL MOVE ACROSS LAKE MICHIGAN WEDNESDAY AFTERNOON WITH
WIND SPEEDS RAPIDLY DIMINISHING WEDNESDAY MORNING AND BECOMING
SOUTHWEST BY EVENING.
A WEAK LOW WILL DEVELOP OVER THE PLAINS WEDNESDAY NIGHT AND QUICKLY
MOVE ACROSS THE NORTHERN LAKES REGION THURSDAY AFTERNOON...
DRAGGING A COLD FRONT ACROSS THE LAKE THURSDAY NIGHT. THE GRADIENT
TIGHTENS BEHIND THIS FRONT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE PLAINS. BUT IN ADDITION TO THE TIGHTENING GRADIENT...COLDER
AIR WILL ALSO BE SPREADING ACROSS THE REGION AND EXPECT NORTHERLY
WINDS GUSTING TO AT LEAST 30 KTS WITH THE POTENTIAL FOR SOME GUSTS
TO 35 KTS. THIS HIGH THEN QUICKLY MOVES EAST ON FRIDAY WITH
SOUTHERLY WINDS DEVELOPING OVER THE LAKE FRIDAY NIGHT AS LOW
PRESSURE LIFTS NORTH ACROSS CANADA. ANOTHER COLD FRONT THEN MOVES
ACROSS THE LAKES REGION SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM WEDNESDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 3 PM WEDNESDAY.
WIND ADVISORY...INZ001-INZ002 UNTIL 1 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
422 AM EST WED NOV 30 2011
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL REPLACE THE ACTIVE WEATHER PATTERN OF THE LAST
FEW DAYS...RESULTING IN DRY CONDITIONS FOR THE REST OF THE WEEK.
HOWEVER...THE DRY WEATHER WILL BE SHORT-LIVED AS A COLD FRONT
ENTERS THE FORECAST AREA THIS WEEKEND BRINGING ANOTHER ROUND OF
PRECIP. AT THIS TIME...MODELS ARE SHOWING MORE OF A RAIN AND
RAIN/SNOW MIX. BEYOND THAT...SOME OF THE COLDEST AIR OF THE SEASON
WILL ENTER CENTRAL INDIANA WITH HIGHS ONLY TOPPING OFF IN THE 30S...
AND LOWS IN THE TEENS AND 20S.
&&
.NEAR TERM /EARLY MORNING AND TODAY/...
YESTERDAY/S LOW PRESSURE SYSTEM HAS MOVED OUT OF CENTRAL INDIANA
WITH THE SURFACE LOW CURRENTLY CENTERED OVER LAKE ONTARIO.
SO...THE ONLY CHALLENGE FOR TODAY WILL BE TIMING IN REGARD TO
CLEARING.
FAR WESTERN PORTIONS OF CENTRAL INDIANA ARE ALREADY STARTING TO
SEE SOME CLEARING. CLOUDS WILL CONTINUE TO BREAK UP FROM WEST TO
EAST THROUGH THE COURSE OF THE MORNING AS HIGH PRESSURE BUILDS
INTO THE FORECAST AREA. ENTIRE AREA SHOULD BE UNDER SUNNY SKIES BY
EARLY AFTERNOON IF NOT SOONER. HOWEVER...DO NOT EXPECT
TEMPERATURES TO RECOVER VERY QUICKLY THIS AFTERNOON. HIGHS WILL
ONLY TOP OFF IN THE UPPER 30S/LOW 40S WITH WEST/NORTHWEST FLOW.
MODELS ARE IN AGREEMENT...SO STUCK CLOSE TO GUIDANCE AND WENT WITH
ALLBLEND.
LATEST OBS ACROSS CENTRAL INDIANA ARE SHOWING TEMPS GENERALLY IN
THE LOW 30S WITH DEWPOINTS IN THE MID TO UPPER 20S. WINDS ARE OUT
OF THE NORTHWEST AT 5 TO 15 MPH.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
A BENIGN WEATHER PATTERN WILL REMAIN IN PLACE THROUGH ENTIRE SHORT
TERM PERIOD AS HIGH PRESSURE DOMINATES THE REGION. SO...THE ONLY
FOCUS WILL BE TEMPS.
FLOW ALOFT BECOMES A TAD MORE ZONAL TONIGHT...BUT SKIES WILL
REMAIN CLEAR. TOMORROW...A WEAK COLD FRONT WILL MOVE THROUGH
CENTRAL INDIANA...BUT IT WILL HAVE LITTLE AFFECT ON TEMPS AND
WILL BE LACKING MOISTURE. SO...WILL CONTINUE TO KEEP FORECAST DRY.
FRIDAY...A BROAD UPPER LEVEL TROUGH WILL MOVE ACROSS THE GREAT
LAKES REGION...CAUSING CLOUDS TO INCREASE ACROSS CENTRAL INDIANA.
LIGHT RAIN/SNOW SHOWERS COULD ALSO JUST SKIM THE NORTHEAST
PORTIONS OF FORECAST AREA ON FRIDAY MORNING WITH THIS DISTURBANCE.
SO INSERTED MENTION OF SLIGHT CHANCE POPS OVER THAT AREA...BUT
CONFIDENCE IS LOW.
TEMPS...STUCK CLOSE TO GUIDANCE FOR TODAY/S HIGHS...WHICH WILL PUT
FORECAST AREA IN THE UPPER 30S/LOW 40S. OVERNIGHT LOWS THE NEXT
FEW NIGHTS WILL BE CHILLY WITH CLEAR SKIES. AS A RESULT...TRENDED
ON COOLER SIDE OF GUIDANCE. LOWS WILL DIP INTO THE 20S TONIGHT AND
TOMORROW NIGHT. THURSDAY...WENT WITH MODEL BLEND...BUT CONFIDENCE
IS LOW DUE TO COLD FRONT PASSAGE. THESE NUMBERS MAY HAVE TO BE
LOWERED WITH FUTURE FORECAST ISSUANCES. FRIDAY...LEANED TOWARD THE
COOLER GFS IN REGARD TO HIGH/S. THE NAM DOES NOT SEEM TO BE
PICKING UP ON INCREASED CLOUD COVER FROM SYSTEM MOVING THROUGH THE
GREAT LAKES. FRIDAY NIGHT...CLOUDS WILL LINGER OVER CENTRAL
INDIANA AS THE NEXT SYSTEM MOVES CLOSER TO THE AREA.
SO...OVERNIGHT LOWS WILL BE A BIT WARMER WITH LOW 30S ACROSS THE
SOUTHERN HALF OF CENTRAL INDIANA AND MID 20S OVER THE NORTHERN HALF.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
BACK SIDE OF BROAD HIGH PRESSURE SHOULD KEEP MOST LOCATIONS DRY TO
START ON SATURDAY...BUT THE PRESENCE OF A WARM FRONT AND SOME WEAK
ISENTROPIC LIFT OVER THE WABASH VALLEY MAY BE ENOUGH TO GENERATE
LIGHT PRECIP IN WESTERN COUNTIES.
MORE SUBSTANTIAL PRECIP SET TO ARRIVE LATE SATURDAY NIGHT INTO
SUNDAY MORNING AS A WAVE OF LOW PRESSURE MOVES FROM THE CENTRAL
PLAINS INTO THE GREAT LAKES AND BRINGS A TRAILING COLD FRONT THROUGH
THE OHIO VALLEY. WHILE MODEL GUIDANCE IN GOOD AGREEMENT ON PRECIP
IMPACTING THE REGION FOR THE SECOND HALF OF THE WEEKEND WITH THE
FRONTAL PASSAGE...SOME DIFFERENCES ARE STILL PRESENT WITH REGARDS TO
THE AMOUNT OF ENERGY ALOFT THAT EJECTS FROM THE DEEP UPPER LOW
REMAINING BACK ACROSS BAJA CALIFORNIA IMPACTING SPEED OF THE
BOUNDARY AND AMOUNT OF MOISTURE PULLED NORTH INTO THE OHIO VALLEY.
FOR NOW WILL TAKE A BLENDED APPROACH WITH RESPECT TO TIMING AND
SPEED OF FRONTAL PASSAGE AND RUN WITH HIGH CHANCE TO LIKELY POPS FOR
SATURDAY NIGHT AND SUNDAY. LOW LEVEL THERMALS ALL SUPPORTIVE OF
PRECIP FALLING AS RAIN THROUGH SUNDAY...WITH POTENTIAL FOR SOME
MIXING WITH LIGHT SNOW SHOWERS SUNDAY NIGHT AND EARLY MONDAY AS THE
FRONT DROPS SOUTH OF THE OHIO RIVER. HIGHS WILL WARM INTO THE 40S
OVER THE WEEKEND.
COLDER AIR ADVECTING INTO THE REGION TO BEGIN THE NEW WEEK WITH A
REINFORCING SHOT OF ARCTIC AIR SET TO ARRIVE BY TUESDAY AS A SHARP
UPPER LOW DROPS INTO THE GREAT LAKES COURTESY OF THE POLAR JET
STREAM. HAVE KEPT DRY CONDITIONS THROUGHOUT FOR CENTRAL INDIANA WITH
LIMITED MOISTURE...BUT PRESENCE OF THE UPPER LOW WOULD APPEAR TO BE
A NICE SETUP FOR SOME LAKE EFFECT SNOWS ON TUESDAY AND THE ECMWF
HINTS AT POSSIBLE LAKE BANDS DROPPING SOUTHEAST FROM LAKE MICHIGAN
AND CLIPPING FAR NORTHEAST COUNTIES THROUGHOUT THE DAY TUESDAY. DOES
APPEAR COLDEST AIR OF THE SEASON ARRIVES FOR TUESDAY AS BOTH OP GFS
AND ECMWF SUGGEST 850MB TEMPS AT -14 TO -12C. HIGHS TUESDAY MAY
STRUGGLE TO GET INTO THE LOWER 30S ACROSS MUCH OF THE AREA. HIGH
PRESSURE RETURNS FOR MIDWEEK WITH A SLOW WARMING TREND.
&&
.AVIATION /DISCUSSION FOR THE 300900Z TAF UPDATE/...
MAIN CHANGE FOR THE UPDATE WAS TO DELAY CLEARING OF THE STRATOCU AT
THE TERMINALS AS RECENT SATELLITE DATA SHOWING REDEVELOPMENT TO THE
LOWER CLOUDS ACROSS WESTERN INDIANA. RUC INDICATING N/NW FLOW AT
925MB WHICH WILL STUNT EASTWARD PROGRESSION TO BACK EDGE OF THE
CLOUDS THROUGH DAYBREAK. STILL EXPECTING CLOUDS TO THIN AT THE
TERMINALS AROUND OR SHORTLY AFTER DAYBREAK.
06Z DISCUSSION FOLLOWS.
LINGERING PRECIPITATION EXPECTED TO END OVER THE TAF SITES BY
ISSUANCE TIME. CEILINGS CONTINUE TO RAPIDLY IMPROVE AS DRIER AIR
ADVECTS INTO THE AREA. LINGERING MVFR CEILINGS IN THE VICINITY OF
KIND/KBMG EXPECTED TO LIFT INTO A 030-040 DECK BY ISSUANCE
TIME....WITH THIS DECK SCATTERING OUT BY 300800Z OR SO. ONCE THIS
CLOUD DECK SCATTERS OUT...LITTLE IN THE WAY OF SIGNIFICANT CLOUD
COVER EXPECTED THROUGH 301800Z.
PRESSURE RISE MAX CURRENTLY WORKING IT/S WAY THROUGH THE LOCAL
AREA...SO SURFACE WIND GUSTS 20-25KTS SHOULD DIMINISH AFTER ABOUT
300800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JAS/RYAN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
114 AM EST WED NOV 30 2011
.AVIATION...
06Z TAFS...WINTER STORM WILL CONTINUE TO WIND DOWN ACROSS THE AREA OVER
THE NEXT SEVERAL HOURS. A FAIRLY PROGRESSIVE UPPER LOW WILL SHIFT
NORTHEASTWARD INTO THE EASTERN GREAT LAKES REGION OVERNIGHT...WITH
DEFORMATION FORCING WANING THROUGH THE OVERNIGHT HOURS. IFR VSBYS
WITH SNOW SHOWERS ARE POSSIBLE AT KFWA OVER NEXT FEW HOURS...WITH
THE THREAT DIMINISHING BY AROUND 08Z AS DEFORMATION BAND CONTINUES
TO WEAKEN AND SHIFT EASTWARD. NORTHWEST WINDS SHOULD REMAIN
SOMEWHAT GUSTY OVERNIGHT...ESPECIALLY AT KFWA...BUT WIND GUSTS AT
BOTH TERMINALS SHOULD SUBSIDE AFTER 09Z. WHILE WEST TO EAST
CLEARING TREND HAS BEEN PROGRESSIVE ACROSS NORTHERN
ILLINOIS...HAVE NOTED SOME MVFR CIGS ON BACK EDGE OF CLOUD DECK
ACROSS EXTREME NERN IL/FAR NWRN INDIANA AND DID INDICATE TEMPO
HIGHER END MVFR CIGS AT KSBN THROUGH 09Z. REMAINDER OF THE
FORECAST SHOULD BE UNEVENTUL WITH SFC RIDGE AXIS SLOWLY BUILDING
INTO THE AREA ALLOWING FOR WINDS TO BACK TO THE WEST AROUND 10
KNOTS ON WEDNESDAY AFTERNOON. VFR CONDITIONS EXPECTED POST 12Z
THIS MORNING.
&&
.PREV DISCUSSION... /ISSUED 720 PM EST TUE NOV 29 2011/
UPDATE...
SUBSTANTIAL CHNGS WRT KSBN AS PROLIFIC MESOBANDED/CONVECTIVE
SNOWFALL TO MOST LKLY RMN EAST OF AIRFLD PER HRRR ANALYSIS. IN
ADDITION...RECENT STRONG SFC PRES RISES ACRS NRN IN SUGGESTS SFC
LOW AND ASSOCD BANDING TO JUMP EWD NEXT FEW HRS. FURTHER
SUBSTANTIATING HRRR IS WV IMAGERY SHOWING TIGHTLY CYCLCLY WOUND
DRY SLOT NOW INTO KFWA WITH ERLIER LULL/IMPROVEMENT TO
7SM...OCCLSN FCST TO SHIFT EWD OF MIDLVL CIRC CENTER NEAR KAOH
ATTM INTO ERN OH BY 06 UTC. FILLING PRECIP ANTICIPATED TO RETURN
EWD INTO KFWA AFT 01 UTC WITH POTNL FOR INTENSE BAND FM KHAI-KASW-
5W KOKK TO SHIFT EWD TO KFWA 02-05 UTC WITH PSBL LIFR MET CONDS.
AS ENTIRE SYSTEM LIFTS OUT TOWARD DAYBREAK...SHARP LWRG OF
SUBSIDENCE INVERSION PER KOXI PROXIMITY LAPS SNDG...TO BRING
ABRUPT END OF SNOW W-E ACRS NRN IN...NLT 03 UTC KSBN TO KFWA
AROUND 05 UTC. STRONG PRES RISES SHOULD BRING PD OF HIR GUSTS INTO
MID/UPR 20S KT RANGE...THOUGH IN ABSENCE OF STRONG CAA AND LWRG
SUBSIDENCE INVERSION THIS UPTICK SHOULD REMAIN SHORT-
LIVED...RELAXING AFTR MIDNIGHT.
ANTICIPATE UPDATE WITHIN NEXT HOUR TO TRIM WRN PERIPHERY ADVISORY
COUNTIES/LKLY DOWNGRADE SOUTH OF KOS/WHITLEY/ALLEN IN COUNTIES TO
ADVISORY. ALL ANTICIPATED CHANGES WL LARGELY BE IN LOCK STEP OF HRRR
3KM HRLY/15 MIN MESODATA...ASSUMPTIVE OF WELL CORRELATED RADAR/METAR
OBS TRENDS.
SHORT TERM.../TONIGHT/
..FIRST WIDESPREAD SNOW OF THE SEASON COMMENCING...
UPDATES ISSUED EARLIER GENERALLY ON TRACK WITH RAPID COOLING OF
COLUMN OCCURRING BETWEEN 18 AND 20Z. MANY LOCATIONS NOW REPORTING
SNOW OR A MIX OF SNOW/SLEET/RAIN. SNOW AMOUNTS INITIALLY MAY BE ON
LIGHTER SIDE WITH MELTING OCCURRING ON SLIGHTLY WARMER SURFACES.
HOWEVER AS UPPER LOW APPROACHES LATE THIS AFTERNOON AND EVENING AND
MESOBANDING BETTER ESTABLISHES SNOWFALL RATES SHOULD INCREASE ACROSS
MUCH OF THE WARNING AREA. SPORADIC LIGHTNING STRIKES SEEN SW OF THE
AREA IN MAIN MESOBAND WHICH WILL TRANSLATE THROUGH THE AREA INTO
TONIGHT.
HEAVIEST SNOWFALL WILL OCCUR BETWEEN 22Z TUES AND 6Z WEDS AS MAIN
DEFORMATION ZONE SHIFTS ACROSS THE FORECAST AREA. SEVERAL RUNS OF
THE HRRR HAVE SHOWN THE MAIN SWATH OF HEAVIER SNOW TO TAKE SHAPE
EITHER SIDE OF A MARION TO ANGOLA TO HILLSDALE LINE. THIS MODEL
DEPICTS UPWARDS OF 8 TO 12 INCHES OF SNOWFALL. THINK THIS IS LIKELY
OVER DONE WITH GREATER CONFIDENCE IN DECENT AREA OF 4 TO 7 INCHES OF
SNOW WITH AMOUNTS APPROACHING 8 ESPECIALLY ACROSS PORTIONS OF
NORTHEASTERN INDIANA INTO FAR SOUTHERN LWR MI AND FAR NW OHIO. WILL
LET EVE SHIFT MONITOR TRENDS OF AMOUNTS AND HEAVIEST BAND AND ADJUST
HEADLINES ACCORDINGLY. TEMPS WILL CONTINUE TO FALL AND BOTTOM OUT IN
THE UPPER 20S TO AROUND 30.
WINDS WILL ALSO INCREASE TONIGHT AS THE TIGHTLY WRAPPED LOW
CONTINUES TO MOVE AWAY. AS WE GET INTO THE OVERNIGHT HOURS THIS
COULD CAUSE SOME DRIFTING AND LOW BLOWING OF THE SNOW...BUT GIVEN
THE INITIAL WET CONTENT...NOT EXPECTED TO BE A SIG IMPACT.
LONG TERM...
MINOR ADJUSTMENTS TO THE TEMPERATURES WEDNESDAY AND WEDNESDAY NIGHT
TO TAKE INTO ACCOUNT OUR LATEST SNOWFALL FORECASTS AND EXPECTED
CLOUD COVER. HAVE NUDGED TEMPS DOWN FOR THE MAX T AND UP FROM
PREVIOUS GRIDS FOR OVERNIGHT LOW. WITH CYCLONIC FLOW OVER THE REGION
EXPECT THAT CLOUDS WILL PERSIST AND HAVE INCREASED CLOUD COVER - BUT
MAY NOT HAVE INCREASED ENOUGH FOR THURSDAY.
LONGWAVE PATTERN IS BEGINNING TO BE MUCH MORE AMPLIFIED AND THIS
SETS UP A PROGRESSIVE PATTERN OVER THE GREAT LAKES REGION BEGINNING
THURSDAY WITH ANOTHER VIGOROUS SHORTWAVE TO TO DIVE OUT OF THE
NORTHERN PLAINS BY SATURDAY...LEADING TO ANOTHER SHOT OF COLDER AIR
POISED TO DROP OUT OF THE CANADIAN PLAINS THIS COMING WEEKEND.
WITH A BRIEF WARMING TREND THU/FRI TEMPS WILL BE BELOW NORMAL
BEGINNING SAT-NEXT TUES.
WITH THE INCOMING SHORTWAVE ON SATURDAY...HAVE INCREASED POP TO MORE
CLOSELY MATCH SURROUNDING OFFICES AND WOULD EXPECT TO SEE ANOTHER
ACCUMULATING SNOWFALL DURING THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
INZ027-033-034.
WINTER STORM WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
INZ006>009-017-018-025-026.
MI...WINTER STORM WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
MIZ080-081.
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR OHZ005-
016-024-025.
WINTER WEATHER ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
OHZ015.
WINTER STORM WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
OHZ001-002-004.
LM...GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LMZ043-046.
&&
$$
SHORT TERM...FISHER
LONG TERM...LEWIS
UPDATE...MURPHY
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1134 PM CST TUE NOV 29 2011
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE FORECAST (TONIGHT AND WEDNESDAY)...
20Z WATER VAPOR IMAGERY AND ASSOCIATED 500 MB RUC ANALYSIS SHOWS A
DEEP CUT OFF LOW PRESSURE SYSTEM SLOWLY MOVING NORTHEASTWARD THROUGH
THE OHIO RIVER VALLEY...BRINGING NORTHWESTERLY MID LEVEL FLOW OVER
THE CENTRAL U.S. A SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST
FLOW IS CURRENTLY PUSHING THROUGH THE AREA...HOWEVER MEAGER LIFT
FROM THIS QUICKLY MOVING SHORTWAVE WILL ONLY BRING SOME SCATTERED
HIGH CLOUDS FOR THIS AFTERNOON. AT THE SURFACE A SURFACE RIDGE OF
HIGH PRESSURE CURRENTLY SITS OVER CENTRAL KANSAS CREATING TIGHT
GRADIENT WITH SUBSEQUENT GUSTY NORTH-NORTHWEST WINDS ACROSS FAR
EASTERN KANSAS. A NARROW BAND OF DRY AIR HAS MOVED INTO NORTH
CENTRAL KANSAS AS DEWPOINTS HAVE MIXED INTO THE SINGLE
DIGITS...HOWEVER DUE TO THE LIGHT WINDS NEAR THE CENTER OF THE
SURFACE HIGH...FIRE DANGER IS NOT VERY HIGH IN THIS AREA DESPITE THE
VERY DRY AIR.
OVERNIGHT THE SURFACE RIDGE MOVES OVER NORTHEAST KANSAS CAUSING
WINDS TO GO CALM. WITH SKIES CLEARING OUT RADIATIONAL COOLING WILL
ALLOW TEMPERATURES TO DROP INTO THE LOWER TO MID 20S. WOULD HAVE
GONE A LITTLE COOLER IN NORTH CENTRAL KANSAS BUT SOUTHERLY FLOW
ALONG THE WESTERN EDGE OF THE EASTWARD MOVING SURFACE RIDGE WILL
ALLOW FOR SOME WEAK WARM AIR ADVECTION AS WELL AS SOME BOUNDARY
LAYER MIXING. THESE FACTORS WILL HELP TO KEEP TEMPERATURES A LITTLE
WARMER THAN AREAS FURTHER EAST. LOW LYING AREAS AND RIVER VALLEYS
EAST OF HIGHWAY 75 COULD SEE TEMPS DROP INTO THE UPPER TEENS AS
SOUTHERLY FLOW WILL LIKELY NOT BEGIN IN THESE AREAS UNTIL EARLY WED
MORNING.
WEDNESDAY WILL BRING ANOTHER MOSTLY CLEAR DAY WITH SLIGHTLY WARMER
TEMPERATURES THAN TUESDAY. SOUTHERLY FLOW WILL ALLOW FOR WARM AIR
ADVECTION EAST OF A DEEPENING SURFACE TROUGH WHICH WILL COME OFF THE
WESTERN HIGH PLAINS AND MOVE EAST INTO THE CENTRAL PLAINS. UTILIZED
A MIX DOWN METHOD FROM THE 900 MB LEVEL FOR WEDNESDAYS HIGHS.
TIGHTENING SURFACE PRESSURE GRADIENT BETWEEN THE DEEPENING LOW AND
THE DEPARTING SURFACE HIGH WILL CAUSE THE SOUTHERLY WINDS TO PICK UP
IN INTENSITY THROUGHOUT THE DAY ON WEDNESDAY.
JL
EXTENDED RANGE FORECAST (WEDNESDAY NIGHT THROUGH TUESDAY)...
AN UPPER LEVEL TROUGH WILL DIG SOUTHWARD ACROSS THE WESTERN CONUS
INTO THE DESERT SOUTHWEST BY THURSDAY EVENING. A MINOR H5 WILL MOVE
EAST ACROSS THE NORTHERN AND CENTRAL PLAINS WEDNESDAY NIGHT.
LOW-LEVEL CAA ACROSS THE NORTHERN PLAINS WILL CAUSE A SURFACE COLD
FRONT TO PUSH SOUTHWARD ACROSS THE CWA THURSDAY MORNING. HIGHS MAY
OCCUR DURING THE MID AND LATE MORNING HOURS ON THURSDAY ACROSS
SOUTHEAST KS...WITH TEMPERATURES HOLDING STEADY OR SLOWLY FALLING
INTO THE LOWER 40S BY AFTERNOON. NORTH WINDS WILL INCREASE 20 TO 25
MPH WITH GUSTS OF 35 TO 45 MPH BEHIND THE COLD FRONT. THERE MAY BE
SOME SNOW FLURRIES EARLY THURSDAY MORNING ACROSS THE NORTHERN
COUNTIES OF THE CWA.
FRIDAY...WILL BE COOL WITH INCREASING HIGH CLOUDINESS. WINDS WILL
SHIFT TO THE SOUTHEAST BY LATE AFTERNOON AS A LEE SFC TROUGH DEEPENS
ACROSS THE HIGH PLAINS. HIGHS ON FRIDAY WILL ONLY REACH THE MID TO
UPPER 30S. THE NAM MODEL SOLUTION HAS BEEN VERY INCONSISTENT AND
ERRONEOUS THE PAST 48 HOURS. THE NAM IS WAY TOO PROGRESSIVE LIFTING
THE CLOSED UPPER LOW INTO THE SOUTHERN HIGH PLAINS LATE FRIDAY
AFTERNOON. IF FOR SOME REASON IT WERE TO VERIFY THEN PRECIP MAY
BEGIN DEVELOPING ACROSS THE SOUTHERN COUNTIES OF THE CWA LATE FRIDAY
AFTERNOON AND SPREAD NORTHWARD INTO THE EARLY EVENING HOURS. ALL
OTHER OPERATIONAL NUMERICAL MODELS SHOW THE CLOSED UPPER LOW
REMAINING ACROSS THE DESERT SOUTHWEST INTO FRIDAY NIGHT.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...A PIECE OF THE UPPER LOW
ACROSS THE DESERT SOUTHWEST WILL LIFT NORTHEAST INTO THE CENTRAL
PLAINS ON SATURDAY. THE ECMWF MODEL SHOWS STRONG WAA DEVELOPING
FRIDAY NIGHT WHICH SHOULD CAUSE SFC TEMPS AND DEWPOINTS TO RISE
ABOVE FREEZING ACROSS MUCH OF THE CWA BY 6Z SAT. THE GFS AND GEM
HAVE BEEN CONVERGING TOWARDS THE ECMWF...BUT CONTINUE TO BE A BIT
COOLER. I WILL BE LEANING A BIT MORE TOWARDS THE ECMWF DURING THIS
FORECAST PERIOD. LOW TEMPERATURES WILL OCCUR DURING THE MID EVENING
HOURS OF FRIDAY...THEN SLOWLY RISE THROUGH THE NIGHT. ISENTROPIC
LIFT AND ASCENT AHEAD OF THE APPROACHING H5 TROUGH WILL CAUSE LIGHT
RAIN TO DEVELOP. IF THERE IS ENOUGH LOW-LEVEL DRY AIR IN PLACE AS
THE RAIN DEVELOPS THEN WET-BULB COOLING MAY ALLOW SURFACE
TEMPERATURES ACROSS THE NORTHERN AND WESTERN COUNTIES TO DROP BELOW
FREEZING. THERE MAY BE SOME LIGHT PERIODS OF FREEZING RAIN FRIDAY
EVENING BEFORE IT CHANCES TO LIGHT RAIN. ROAD SURFACE ARE FAIRLY
WARM...THUS THE ONLY SLICKS SPOTS THAT MAY DEVELOP FRIDAY EVENING
MAY BE ON BRIDGES AND OTHER ELEVATED ROAD SURFACES.
THE RAIN ON SATURDAY MAY BEGIN TO MIX WITH SNOW ACROSS NORTH CENTRAL
KS DURING THE AFTERNOON HOURS AS THE H5 TROUGH LIFTS NORTHEAST
ACROSS CENTRAL KS INTO EASTERN NE. THE NORTHERN COUNTIES MAY SEE A
PERIOD OF LIGHT SNOW SATURDAY NIGHT...THE RAIN WILL MIX WITH SNOW
ACROSS THE REMAINDER OF THE CWA THROUGH THE EVENING HOURS. THERE MAY
BE A BRIEF PERIOD OF LIGHT SNOW ACROSS NORTHEAST AND EAST CENTRAL KS
BEFORE THE PRECIP MOVES EAST OF THE CWA LATE SATURDAY NIGHT INTO
SUNDAY MORNING. ATTM...THE ACCUMULATING SNOW WILL MOST LIKELY
REMAIN WEST AND NORTH OF THE CWA...FROM WEST CENTRAL KS INTO EASTERN
NE WHERE SEVERAL INCHES OF SNOW MAY ACCUMULATE. THE NORTH CENTRAL
COUNTIES MAY SEE AROUND AN INCH OF SNOW ON GRASSY SURFACES SATURDAY
NIGHT. HIGHS ON SATURDAY WILL REACH THE LOWER TO MID 40S SOUTH OF
I-70 WITH MID TO UPPER 30S NORTH OF I-70. OVERNIGHT LOWS ON SATURDAY
WILL SLOWLY DROP INTO THE 20S.
SUNDAY THROUGH TUESDAY...THE MAIN H5 LOW WILL REMAIN CUTOFF ACROSS
THE SOUTHWEST CONUS AS A LONGER WAVE LENGTH H5 TROUGH DEVELOPS
ACROSS THE EASTERN CONUS. NORTHWEST FLOW ALOFT AND A COLD SFC HIGH
PRESSURE WILL KEEP HIGHS IN THE MID 30S AND OVERNIGHT LOWS IN THE
TEENS AND LOWER 20S.
GARGAN
&&
.AVIATION...
VFR TO CONTINUE THROUGH THE PERIOD. WINDS LIGHT AND VARIABLE EARLY
WITH SURFACE HIGH OVER TERMINALS THEN BECOMING SOUTH NEAR 8 KTS BY
14Z. WINDS INCREASING TO AROUND 12 KTS WITH GUSTS NEAR 21 KTS
AFTER 18Z. WINDS THEN DECOUPLE AND BACK TO SOUTH SOUTHEAST UNDER 10
KTS AFTER 01/00Z. DRY BOUNDARY LAYER WILL INHIBIT FOG FORMATION.
53
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
306 AM EST WED NOV 30 2011
.SYNOPSIS...
RAIN AND SNOW SHOWERS WILL DIMINISH TODAY AS LOW PRESSURE MOVES OFF
TO THE NORTHEAST. BELOW NORMAL TEMPERATURES WILL PERSIST INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE EARLY MORNING HOURS...FORECAST AREA IS GENERALLY
SURROUNDED BY LIGHT PRECIPITATION...WITH LITTLE ACTUALLY OCCURRING
IN THE FORECAST AREA ITSELF. AS WINDS BECOME MORE WESTERLY BY
DAWN...EXPECT THAT COVERAGE OF PRECIPITATION SHOULD PICK UP.
SYNOPTIC MODELS GENERALLY SHOW A FEW HUNDREDTHS OF PRECIPITATION IN
ALL LOCATIONS THROUGH THE MORNING...BUT ALL HI-RES MODELS INDICATE
THAT THE DEFORMATION ZONE CURRENTLY OVER NORTHWEST OHIO WILL SIMPLY
SLIDE NORTHEAST...POSSIBLY CLIPPING SOME EASTERN OHIO AND NORTHWEST
PA COUNTIES. WITH SUCH STRONG AGREEMENT FROM THE HI-RES
MODELS...WILL TRUST THEM FOR THE FIRST 6-12 HOURS OF THE FORECAST.
WILL STILL INCLUDE SOME UPSLOPE SHOWERS ALONG THE RIDGES AS WELL. AS
FOR P-TYPE...CURRENT IR SATELLITE IMAGES SHOW ONLY SCATTERED
COVERAGE OF CLOUD TOP TEMPERATURES COLDER THAN -10C...AND MODEL
SOUNDINGS INDICATE THAT CLOUD TOPS SHOULD REMAIN BETWEEN -10C AND
0C. IF THIS HOLDS...THEN LITTLE ICE CRYSTAL GROWTH WOULD BE EXPECTED
AND WITH SURFACE TEMPERATURES IN MOST LOCATIONS REMAINING ABOVE
FREEZING...PRECIP SHOULD FALL AS DRIZZLE OR LIGHT RAIN. ALONG THE
RIDGES...SOME FREEZING DRIZZLE COULD MIX IN WITH SNOW SHOWERS.
PRECIP WILL DIMINISH QUICKLY DURING THE AFTERNOON HOURS. EXPECT
LITTLE RISE IN TEMPERATURES DURING THE DAY WITH COLDER AIR FILTERING
IN. WINDS WILL ALSO BE A BIT GUSTY...RANGING FROM 20 MPH IN THE
SOUTH TO 30 MPH IN THE NORTH.
SKIES WILL CLEAR OUT OVERNIGHT AS HIGH PRESSURE MOVES IN FROM THE
SOUTHWEST. CANNOT RULE OUT THE CHANCE FOR SOME FOG TO FORM OVERNIGHT
IF LOW LEVEL INVERSION SETS UP AS INDICATED BY THE NAM.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL KEEP CONDITIONS DRY THURSDAY AND THURSDAY NIGHT.
WEAK FRONT WILL PASS THE REGION FRIDAY...BUT MODELS SHOW THAT
SOUTHERNMOST EXTENT OF PRECIPITATION SHOULD REMAIN ALONG THE I-80
CORRIDOR. HAVE KEPT PREVIOUS FORECAST OF SLIGHT CHANCE POPS NORTH OF
THE INTERSTATE. LITTLE CHANGE EXPECTED IN WEATHER FOR SATURDAY.
TEMPERATURES WILL WARM BY 2-3 DEGREES EACH DAY...GOING A FEW DEGREES
ABOVE NORMAL BY SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
MODEL TIMING ISSUES EXIST WITH THE NEXT SYSTEM PROGGED TO
APPROACH THE REGION LATE SUNDAY. CURRENTLY MODELS INDICATE A
SERIES OF SHORTWAVES DEEPENING THE POSITIVELY TILTED UPPER LEVEL
TROUGH AND ALLOWING FOR VERY COLD H850 TEMPERATURES OVER CANADA TO
SINK SOUTHWARD TO AS FAR AS MISSISSIPPI VALLEY BY TUESDAY. THIS
COULD ALLOW FOR WIDESPREAD SNOW SHOWERS OVERNIGHT MONDAY INTO
TUESDAY BUT GENERALLY KEPT POPS IN THE CHANCE CATEGORY THROUGH THE
PERIOD AT THIS TIME DUE TO UNCERTAINTY. WITH THE H850 TEMPERATURES
REACHING -12C AND NORTHWEST FLOW...HIGH TEMPERATURES COULD BE 10
DEGREES BELOW NORMAL TUESDAY.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA AND HRRR AND NAM MODEL OUTPUT,
EXPECT POST SYSTEM TROWAL-RELATED/SO-CALLED WRAP AROUND/ MVFR
STRATOCUMULUS AND LIGHT PRECIPITATION TO AFFECT THE UPPER OHIO
VALLEY INTO LATE AFTERNOON. BRIEF IFR RESTRICTIONS MAY OCCUR THIS
MORNING, BUT LACK SUFFICIENT CONFIDENCE TO PINPOINT ITS OCCURRENCE.
EXPECT PRECIPITATION TYPE TO BE MAINLY DRIZZLE, ALBEIT BRIEF SNOW
FLURRIES CANNOT BE RULED OUT. NAM MODEL PROFILES SHOW CLOUD TOPS
GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION. HOWEVER, RECENT
SATELLITE DATA DOES SHOW SOME HIGHER COLDER CLOUDS PASSING OVER
THE SHALLOW WARMER CLOUDS, SO SOME SEEDER FEEDER ICE NUCLEATION
MAY OCCUR THIS MORNING.
FAST FLOW ALOFT WILL MIX DOWN TO PROMOTE SURFACE WIND GUSTS OF 25
KTS TODAY. WINDS WILL SUBSIDE AT SUNDOWN, WHEN REMAINING CLOUD
CEILINGS WILL LIKEWISE DISSIPATE.
OUTLOOK...THURSDAY THROUGH SUNDAY....
MAINLY VFR. ONLY POTENTIAL FOR RESTRICTIONS CAN BE EARLY MORNING FOG
THURSDAY RELATED TO A SHALLOW SURFACE TEMPERATURE INVERSION, AND
POSSIBLE SHOWERS NEAR I-80 FRIDAY NIGHT WITH A COLD FRONT PASSING
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
101 AM EST WED NOV 30 2011
.SYNOPSIS...
SNOW SHOWERS CAN BE EXPECTED OVERNIGHT AND WEDNESDAY AS COLDER
AIR MOVES OVER THE UPPER OHIO VALLEY IN THE WAKE OF TODAYS FRONTAL
PASSAGE. DRY WEATHER AND SEASONAL TEMPERATURES ARE FORECAST FOR
THE LATTER PART OF THE WEEK AS HIGH PRESSURE BUILDS.
&&
.NEAR TERM /THROUGH TODAY/...
EXCEPT FOR RADAR RETURNS ALONG THE PENNSYLVANIA RIDGES...RADAR
RETURNS HAVE REALLY DIED OFF ACROSS THE FORECAST AREA. PRIMARY
CHANGE WITH THE 06Z UPDATE WAS TO BACK OFF ON POPS IN THE NEAR
TERM...BUT STILL THINK THAT LIKELY POPS ARE WARRANTED FOR ALL
LOCATIONS JUST BEFORE SUNRISE AS UPPER LOW MOVES NORTHEAST AND
DEFORMATION ZONE APPROACHES FROM THE WEST. PREVIOUS DISCUSSION
FOLLOWS.
LATE EVE UPDATE ISSUED TO ACCOUNT FOR LATEST TRENDS AS PER RADAR
AND OBS. COLDER AIR WAS SWEEPING ACROSS OHIO TONIGHT UNDER ADVNG
MID/UPR LOW PRESSURE. THAT COLDER AIR...ALONG WITH SOME RAIN AND
SNOW SHOWERS...WL AFFECT THE REGION TONIGHT AS THE LOW PROGRESSES
NEWD. WITH TEMPERATURES REMAINING ABOVE FREEZING FOR THE MOST
PART...LIGHT ACCUMULATION SHOULD BE CONFINED TO GRASSY AREAS. THE
EXCEPTION WL BE FOR THE RIDGES WHERE A GENERAL ONE TO THREE
INCHES LOOKS REASONABLE BEFORE LOWERING INVERSION SUPPRESSES THE
SNOW SHOWERS ON WEDNESDAY.
COLD ADVECTION UNDER THE PASSING TROUGH ALOFT SUPPORTS CONTD SNOW
SHOWERS ON WEDNESDAY WITH CATEGORICAL POP NUMBERS FORECAST OVR
AREAS FM I 80 NWD. RELATIVELY WARM BOUNDARY LAYER TEMPS SHOULD
PRECLUDE ANY SIGNIFICANT ACCUMULATION.
TEMPERATURES WERE FORECAST USING NAM GUIDANCE AND SHOULD AVERAGE
OUT CLOSE TO NORMAL FOR THE NEAR TERM.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
HIGH PRESSURE IS PROJECTED TO BEGIN BUILDING OVR THE UPR OH REGION
ON WED NGT...HENCE SNOW SHOWER CHANCES WERE REDUCED MORE RAPIDLY
THAN PREVIOUS PROGS WITH DRY WEATHER CONTD THROUGH THURSDAY. THERE
ARE A FEW MODEL TIMING ISSUES WITH THE WEAK OPEN SHORTWAVE DROPPING
THROUGH THE GREAT LAKES ON FRIDAY. KEPT CLOSER TO THE 00Z/12Z
GFS/ECMWF SINCE THE NAM SEEMS TO BE SLOWER. REGARDLESS..WITH LITTLE
MOISTURE ASSOCIATED WITH THE SYSTEM...NOT MUCH MORE THAN A WIND
SHIFT AND A BRIEF DIP IN TEMPERATURES IS EXPECTED. KEPT SLIGHT
CHANCE POPS FOR THE COUNTIES NORTH OF I-80 WITH SNOW FLURRIES
POSSIBLE TOWARDS EVENING.
ALTHOUGH THERE WILL BE A SLIGHT MODERATION IN TEMPS DURING THE
SHORT TERM PERIOD...READINGS WERE FORECAST CLOSE TO NORMAL USING
GUIDANCE BLEND.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AFTER THE AFOREMENTIONED DISTURBANCE PASSES FRIDAY...HIGH PRESSURE
WILL ONCE AGAIN BUILD OVER THE REGION FOR THE WEEKEND. MODEL
TIMING ISSUES EXIST WITH THE NEXT SYSTEM PROGGED TO APPROACH THE
REGION LATE SUNDAY. CURRENTLY MODELS INDICATE A SERIES OF
SHORTWAVES DEEPENING THE POSITIVELY TILTED UPPER LEVEL TROUGH AND
ALLOWING FOR VERY COLD H850 TEMPERATURES OVER CANADA TO SINK
SOUTHWARD TO AS FAR AS MISSISSIPPI VALLEY BY TUESDAY. THIS COULD
ALLOW FOR WIDESPREAD SNOW SHOWERS OVERNIGHT MONDAY INTO TUESDAY
BUT GENERALLY KEPT POPS IN THE CHANCE CATEGORY THROUGH THE PERIOD
AT THIS TIME DUE TO UNCERTAINTY. WITH THE H850 TEMPERATURES
REACHING -12C AND NORTHWEST FLOW...HIGH TEMPERATURES COULD BE 10
DEGREES BELOW NORMAL TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA AND HRRR AND NAM MODEL OUTPUT,
EXPECT POST SYSTEM TROWAL-RELATED/SO-CALLED WRAP AROUND/ MVFR
STRATOCUMULUS AND LIGHT PRECIPITATION TO AFFECT THE UPPER OHIO
VALLEY INTO LATE AFTERNOON. BRIEF IFR RESTRICTIONS MAY OCCUR THIS
MORNING, BUT LACK SUFFICIENT CONFIDENCE TO PINPOINT ITS OCCURRENCE.
EXPECT PRECIPITATION TYPE TO BE MAINLY DRIZZLE, ALBEIT BRIEF SNOW
FLURRIES CANNOT BE RULED OUT. NAM MODEL PROFILES SHOW CLOUD TOPS
GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION. HOWEVER, RECENT
SATELLITE DATA DOES SHOW SOME HIGHER COLDER CLOUDS PASSING OVER
THE SHALLOW WARMER CLOUDS, SO SOME SEEDER FEEDER ICE NUCLEATION
MAY OCCUR THIS MORNING.
FAST FLOW ALOFT WILL MIX DOWN TO PROMOTE SURFACE WIND GUSTS OF 25
KTS TODAY. WINDS WILL SUBSIDE AT SUNDOWN, WHEN REMAINING CLOUD
CEILINGS WILL LIKEWISE DISSIPATE.
OUTLOOK...THURSDAY THROUGH SUNDAY....
MAINLY VFR. ONLY POTENTIAL FOR RESTRICTIONS CAN BE EARLY MORNING FOG
THURSDAY RELATED TO A SHALLOW SURFACE TEMPERATURE INVERSION, AND
POSSIBLE SHOWERS NEAR I-80 FRIDAY NIGHT WITH A COLD FRONT PASSING
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
257 AM EST WED NOV 30 2011
.SYNOPSIS...
COLD AND DRY HIGH PRESSURE WILL BUILD INTO THE CAROLINAS THROUGH
FRIDAY. A DRY COLD FRONT IS EXPECTED TO PUSH SOUTH OVER THE AREA
EARLY SATURDAY. A WARMING TREND WILL OCCUR LATE IN THE WEEKEND
INTO EARLY NEXT WEEK. A COLD FRONT WILL APPROACH ON TUESDAY
BRINGING THE NEXT CHANCE OF RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...THE ANOMALOUSLY COLD UPPER LOW THAT BROUGHT
SNOW TO PARTS OF THE SOUTHEAST YESTERDAY IS NOW LIFTING RAPIDLY
NORTH INTO THE EASTERN GREAT LAKES. THE COLDEST AIR AT 850 MB
BYPASSED THE EASTERN CAROLINAS WELL TO THE NORTH AND WEST...AND IN
FACT WESTERLY WINDS ARE ALREADY BRINGING IN WARMER AIR AT 850 MB.
HIGH PRESSURE CENTERED OVER THE SOUTHERN PLAINS WILL MOVE TO
TENNESSEE AND MISSISSIPPI THIS EVENING...AND ON INTO WEST VIRGINIA
BY DAYBREAK THURSDAY. THIS WILL ALLOW OUR SURFACE WINDS TO VEER FROM
WESTERLY THIS MORNING TO NORTHERLY LATE TONIGHT.
AN AREA OF STRATUS ACROSS THE NC EASTERN PIEDMONT AND COASTAL PLAIN
IS THE RESULT OF LOW-LEVEL MOISTURE TRAPPED UNDERNEATH A BUILDING
SUBSIDENCE INVERSION ALOFT. THE GFS DOES NOT SEE THIS MOISTURE...
HOWEVER THE NAM AND HRRR DO. BOTH OF THESE MODELS FORECAST THE LOW
CLOUDS TO CONTINUE SLIDING EAST-SOUTHEAST THROUGH DAYBREAK...THEN
BURNING OFF BY 10 AM. SKIES SHOULD BECOME SUNNY THROUGHOUT THE
EASTERN CAROLINAS TODAY WITH HIGHS 55-57. CLEAR SKIES WILL CONTINUE
TONIGHT WITH ONLY A LIGHT NORTHERLY BREEZE EXPECTED. LOWS SHOULD
FALL INTO THE LOWER 30S EXCEPT A FEW DEGREES WARMER NEAR THE COAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL BE BUILDING IN FROM THE
WEST THURSDAY THROUGH FRI AS RIDGE BUILDS IN THROUGH THE MID TO
UPPER LEVELS. EXPECT PLENTY OF SUBSIDENCE WITH A COOL AND DRY AIR
MASS IN PLACE IN A DEEP NORTHERLY FLOW THROUGH MOST OF THE SHORT
TERM PERIOD. GRADIENT WEAKENS LATE THURS INTO FRI PROVIDING BETTER
RADIATIONAL COOLING CONDITIONS THURS NIGHT. OVERNIGHT LOW TEMP
READINGS WILL DROP CLOSE TO FREEZING IN MANY PLACES AS DEWPOINT
TEMPS RUN NEAR 30 OR BELOW. DAY TIME HIGHS WILL HAVE TROUBLE
REACHING 60 ON THURS WITH PLENTY OF LATE FALL SUNSHINE. AS 850
TEMPS REBOUND AND H5 HEIGHTS RISE...TEMPS BEGIN TO WARM INTO THE
60S BY FRI AFTN.
THE HIGH PRESSURE BECOMES DISPLACED TEMPORARILY AS A DRY BACK DOOR
FRONT MOVES DOWN FROM THE NORTH LATE FRI...BUT RIDGE ALOFT WILL
HOLD IT MAINLY NORTH OF AREA. NORTHERLY WINDS MAY BACK BRIEFLY TO
THE W-NW BUT OVERALL COOL AND DRY WEATHER WILL CONTINUE ON INTO
THE WEEKEND. PCP WATER VALUES WILL BE DOWN NEAR A QUARTER OF AN
INCH THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...STRONG HIGH PRESSURE WILL CONTINUE TO RIDGE
DOWN THE EAST COAST FROM NEW ENGLAND. AS THE CENTER SHIFTS OFF
SHORE LATE SAT THE WINDS WILL BEGIN TO SHIFT BECOMING MORE ON
SHORE THROUGH SUNDAY AS THE HIGH PROGRESSES FARTHER EAST. RIDGE
HOLDS ON IN THE MID TO UPPER LEVELS WITH HEIGHTS INCREASING
THROUGH SAT AND REMAINING FAIRLY STABLE THROUGH EARLY MONDAY. BY
SUNDAY MOISTURE WILL BEGIN TO RETURN TO THE FORECAST AREA AS
RETURN FLOW SETS UP ALOFT. PCP WATER VALUES BEGIN TO CREEP BACK UP
TOWARD A HALF TO THREE QUARTERS OF AN INCH. SURFACE FLOW WILL BE A
LITTLE SLOWER TO COME AROUND TO A MORE SOUTHERLY DIRECTION AS HIGH
PRESSURE CONTINUES TO RIDGE DOWN FROM THE NORTHEAST. MAY SEE SOME
CLOUDS BACK IN THE FORECAST BY SUNDAY.
BY MONDAY AN INCREASINGLY DEEPER WARMER AND MOISTER RETURN FLOW
SETS UP. THE GRADIENT TIGHTENS AND LOW LEVEL FLOW SHOOTS UP TO 30
TO 40 KTS. THIS WILL PRODUCE A SURGE IN BOTH WARMTH AND MOISTURE
MON INTO TUES WITH TEMPS BACK UP WELL ABOVE NORMAL. EXPECT READINGS
AROUND 70 MON AND TUES. AS MOISTURE INCREASES AND PCP WATER VALUES
INCREASE UP NEAR AN INCH MON INTO TUES...THERE WILL BE AN
INCREASING CHC OF PCP IN THE FORECAST.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...EXPECT VFR THROUGH PERIOD AS HIGH PRESSURE BUILDS INTO
THE REGION. ONE OR TWO SHREDS OF STRATOCUMULUS MAY LINGER
OVERNIGHT...CERTAINLY BECOMING SKC BY DAYBREAK. GUSTS HAVE MOSTLY
SUBSIDED...BUT CANNOT RULE OUT ADDITIONAL BRIEF GUSTS AOB 20KTS. BY
THIS AFTERNOON WINDS WILL BECOME NORTH-NORTHWEST AND CONTINUE
THROUGH TONIGHT...SUBSIDING TO 5 KTS OR LESS BY THIS EVENING.
EXTENDED OUTLOOK...EXPECT VFR THROUGH PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...WESTERLY WINDS WHIPPING ACROSS THE COASTAL
WATERS EARLY THIS MORNING ARE THE RESULT OF HIGH PRESSURE OVER THE
SOUTHERN PLAINS BUILDING EASTWARD. MODELS ARE IN EXCELLENT AGREEMENT
THAT THE TIGHTEST PORTION OF THE PRESSURE GRADIENT (AND HENCE THE
STRONGEST WINDS) SHOULD ABATE WITHIN THE NEXT 3-4 HOURS...WITH
IMPROVING CONDITIONS THIS MORNING INTO THIS AFTERNOON. AS OFTEN
OCCURS DURING THESE SITUATIONS A NOCTURNAL SURGE OF COLD AIR WILL
PUSH OUT ACROSS THE WATERS THIS EVENING...WITH WIND SPEEDS
INCREASING TO 15-20 KT AWAY FROM SHORE. SEAS AT THE FRYING PAN
SHOALS BUOY ARE 7 FT THIS MORNING WITH 4 FOOT SEAS STILL REPORTED AT
THE NEARSHORE WRIGHTSVILLE BEACH CORMP BUOY. GIVEN THE WESTERLY
FETCH NEARSHORE SEAS SHOULD DIMINISH RATHER QUICKLY THIS
MORNING...BUT IT MAY TAKE SOME MORE TIME TO SEE IMPROVEMENT SOUTH
AND EAST OF BALD HEAD ISLAND WHERE A MORE-SIGNIFICANT EFFECTIVE
FETCH EXISTS. WE WILL EXTEND THE SMALL CRAFT ADVISORY ANOTHER FEW
HOURS FOR THE NC WATERS...BUT ALLOW IT END ON SCHEDULE FOR THE SC
WATERS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...NORTHERLY WINDS WILL CONTINUE THROUGH MUCH
OF THE PERIOD AS HIGH PRESSURE BUILDS IN FROM THE WEST. GRADIENT
WILL RELAX AS CENTER OF HIGH SHIFTS CLOSER OVERHEAD LATE THURS
INTO FRI AND MAY SEE A LITTLE SURGE OVERNIGHT FRI AS BACK DOOR
FRONT PUSHES SOUTH AND HIGH PRESSURE REASSERTS ITSELF. WINDS
SPEEDS ARE EXPECTED TO DIMINISH TO 15 KNOTS OR LESS THURSDAY
NIGHT INTO FRI WITH SEAS 4FT OR LESS.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL RIDGE DOWN INTO THE
CAROLINAS FROM CENTER UP IN NEW ENGLAND. THIS AREA WILL GET
STRETCHED AS CENTER SHIFTS OFF THE NEW ENGLAND COAST AND MOVES
FURTHER OFF SHORE THROUGH SUNDAY. NORTHERLY WINDS UP CLOSER TO 15
KTS ON SAT WILL DIMINISH AND VEER AROUND THROUGH SUNDAY BECOMING
MORE ON SHORE BUT REMAINING LESS THAN 15 KTS THROUGH EARLY NEXT
WEEK. SEAS WILL BASICALLY BE 2 TO 4 FT WITH A SLIGHTLY LONGER
PERIOD SOUTHEAST SWELL MIXING IN THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/SGL
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1052 AM EST WED NOV 30 2011
.SYNOPSIS...
RAIN AND SNOW SHOWERS WILL DIMINISH TODAY AS LOW PRESSURE MOVES OFF
TO THE NORTHEAST. BELOW NORMAL TEMPERATURES WILL PERSIST INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED WEATHER TYPE...TEMPS...AND SNOW AMOUNTS FOR THE RIDGE
LOCATIONS FOR THE MID MORNING UPDATE. WHILE CLOUD TOP TEMPERATURES
CONTINUE TO BE AN ISSUE ALLOWING FOR SOME OF THE PRECIPITATION TO
FALL AS DRIZZLE AND RAIN...THINK THAT AS THE DEFORMATION ZONE
PIVOTS SOUTHEASTWARD...SNOW WILL BE THE PRIMARY WEATHER TYPE. AS
THE WINDS SHIFT MORE NORTHWESTERLY THIS AFTERNOON...SNOW WILL
CONTINUE IN THE HIGHER ELEVATIONS. SINCE 3 INCHES OF SNOW WAS
REPORTED SINCE YESTERDAY IN THE WV RIDGES...FEEL IT REASONABLE
THAT ANOTHER 1-2 COULD FALL BEFORE THE SNOW ENDS TONIGHT. KEPT
TEMPERATURES NEARLY STEADY FOR THE AFTERNOON.
WINDS WILL BE A BIT GUSTY...RANGING FROM 20 MPH IN THE SOUTH TO 30
MPH IN THE NORTH.
SKIES WILL CLEAR OUT OVERNIGHT AS HIGH PRESSURE MOVES IN FROM THE
SOUTHWEST. CANNOT RULE OUT THE CHANCE FOR SOME FOG TO FORM OVERNIGHT
IF LOW LEVEL INVERSION SETS UP AS INDICATED BY THE NAM.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL KEEP CONDITIONS DRY THURSDAY AND THURSDAY NIGHT.
WEAK FRONT WILL PASS THE REGION FRIDAY...BUT MODELS SHOW THAT
SOUTHERNMOST EXTENT OF PRECIPITATION SHOULD REMAIN ALONG THE I-80
CORRIDOR. HAVE KEPT PREVIOUS FORECAST OF SLIGHT CHANCE POPS NORTH OF
THE INTERSTATE. LITTLE CHANGE EXPECTED IN WEATHER FOR SATURDAY.
TEMPERATURES WILL WARM BY 2-3 DEGREES EACH DAY...GOING A FEW DEGREES
ABOVE NORMAL BY SATURDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODEL TIMING ISSUES EXIST WITH THE NEXT SYSTEM PROGGED TO
APPROACH THE REGION LATE SUNDAY. CURRENTLY MODELS INDICATE A
SERIES OF SHORTWAVES DEEPENING THE POSITIVELY TILTED UPPER LEVEL
TROUGH AND ALLOWING FOR VERY COLD H850 TEMPERATURES OVER CANADA TO
SINK SOUTHWARD TO AS FAR AS MISSISSIPPI VALLEY BY TUESDAY. THIS
COULD ALLOW FOR WIDESPREAD SNOW SHOWERS OVERNIGHT MONDAY INTO
TUESDAY BUT GENERALLY KEPT POPS IN THE CHANCE CATEGORY THROUGH THE
PERIOD AT THIS TIME DUE TO UNCERTAINTY. WITH THE H850 TEMPERATURES
REACHING -12C AND NORTHWEST FLOW...HIGH TEMPERATURES COULD BE 10
DEGREES BELOW NORMAL TUESDAY.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA AND HRRR AND NAM MODEL OUTPUT,
EXPECT POST SYSTEM TROWAL-RELATED/SO-CALLED WRAP AROUND/ MVFR
STRATOCUMULUS AND LIGHT PRECIPITATION TO AFFECT THE UPPER OHIO
VALLEY INTO LATE AFTERNOON. BRIEF IFR RESTRICTIONS MAY OCCUR THROUGH THIS
AFTERNOON, BUT LACK SUFFICIENT CONFIDENCE TO PINPOINT ITS OCCURRENCE.
EXPECT PRECIPITATION TYPE TO BE MAINLY DRIZZLE, ALBEIT BRIEF SNOW
FLURRIES CANNOT BE RULED OUT. NAM MODEL PROFILES SHOW CLOUD TOPS
GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION. HOWEVER, RECENT
SATELLITE DATA DOES SHOW SOME HIGHER COLDER CLOUDS PASSING OVER
THE SHALLOW WARMER CLOUDS, SO SOME SEEDER FEEDER ICE NUCLEATION
MAY OCCUR THIS MORNING.
FAST FLOW ALOFT WILL MIX DOWN TO PROMOTE SURFACE WIND GUSTS OF 25
KTS TODAY. WINDS WILL SUBSIDE AT SUNDOWN, WHEN REMAINING CLOUD
CEILINGS WILL LIKEWISE DISSIPATE.
OUTLOOK...THURSDAY THROUGH SUNDAY....
MAINLY VFR. ONLY POTENTIAL FOR RESTRICTIONS CAN BE EARLY MORNING FOG
THURSDAY RELATED TO A SHALLOW SURFACE TEMPERATURE INVERSION, AND
POSSIBLE SHOWERS NEAR I-80 FRIDAY NIGHT WITH A COLD FRONT PASSING
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
825 AM EST WED NOV 30 2011
.SYNOPSIS...
RAIN AND SNOW SHOWERS WILL DIMINISH TODAY AS LOW PRESSURE MOVES OFF
TO THE NORTHEAST. BELOW NORMAL TEMPERATURES WILL PERSIST INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
8AM UPDATE...
ONLY CHANGE WAS TO ADD DRIZZLE...AS MODEL PROFILES SHOW CLOUD
TOPS GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION EARLY TODAY.
THAT WILL CHANGE AS WINDS BECOME MORE WESTERLY LATER THIS
MORNING... EXPECTTHAT COVERAGE OF PRECIPITATION SHOULD PICK UP.
SYNOPTIC MODELS GENERALLY SHOW A FEW HUNDREDTHS OF PRECIPITATION
IN ALL LOCATIONS THROUGH THE MORNING...BUT ALL HI- RES MODELS
INDICATE THAT THE DEFORMATION ZONE CURRENTLY OVER NORTHWEST OHIO
WILL SIMPLY SLIDE NORTHEAST...POSSIBLY CLIPPING SOME EASTERN OHIO
AND NORTHWEST PA COUNTIES. WITH SUCH STRONG AGREEMENT FROM THE HI-
RES MODELS...WILL TRUST THEM FOR THE FIRST 6-12 HOURS OF THE
FORECAST. WILL STILL INCLUDE SOME UPSLOPE SHOWERS ALONG THE RIDGES
AS WELL. AS FOR P-TYPE...CURRENT IR SATELLITE IMAGES SHOW ONLY
SCATTERED COVERAGE OF CLOUD TOP TEMPERATURES COLDER THAN
-10C...AND MODEL SOUNDINGS INDICATE THAT CLOUD TOPS SHOULD REMAIN
BETWEEN -10C AND 0C. IF THIS HOLDS...THEN LITTLE ICE CRYSTAL
GROWTH WOULD BE EXPECTED AND WITH SURFACE TEMPERATURES IN MOST
LOCATIONS REMAINING ABOVE FREEZING...PRECIP SHOULD FALL AS DRIZZLE
OR LIGHT RAIN. ALONG THE RIDGES...SOME FREEZING DRIZZLE COULD MIX
IN WITH SNOW SHOWERS. PRECIP WILL DIMINISH QUICKLY DURING THE
AFTERNOON HOURS. EXPECT LITTLE RISE IN TEMPERATURES DURING THE DAY
WITH COLDER AIR FILTERING IN. WINDS WILL ALSO BE A BIT
GUSTY...RANGING FROM 20 MPH IN THE SOUTH TO 30 MPH IN THE NORTH.
SKIES WILL CLEAR OUT OVERNIGHT AS HIGH PRESSURE MOVES IN FROM THE
SOUTHWEST. CANNOT RULE OUT THE CHANCE FOR SOME FOG TO FORM OVERNIGHT
IF LOW LEVEL INVERSION SETS UP AS INDICATED BY THE NAM.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL KEEP CONDITIONS DRY THURSDAY AND THURSDAY NIGHT.
WEAK FRONT WILL PASS THE REGION FRIDAY...BUT MODELS SHOW THAT
SOUTHERNMOST EXTENT OF PRECIPITATION SHOULD REMAIN ALONG THE I-80
CORRIDOR. HAVE KEPT PREVIOUS FORECAST OF SLIGHT CHANCE POPS NORTH OF
THE INTERSTATE. LITTLE CHANGE EXPECTED IN WEATHER FOR SATURDAY.
TEMPERATURES WILL WARM BY 2-3 DEGREES EACH DAY...GOING A FEW DEGREES
ABOVE NORMAL BY SATURDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODEL TIMING ISSUES EXIST WITH THE NEXT SYSTEM PROGGED TO
APPROACH THE REGION LATE SUNDAY. CURRENTLY MODELS INDICATE A
SERIES OF SHORTWAVES DEEPENING THE POSITIVELY TILTED UPPER LEVEL
TROUGH AND ALLOWING FOR VERY COLD H850 TEMPERATURES OVER CANADA TO
SINK SOUTHWARD TO AS FAR AS MISSISSIPPI VALLEY BY TUESDAY. THIS
COULD ALLOW FOR WIDESPREAD SNOW SHOWERS OVERNIGHT MONDAY INTO
TUESDAY BUT GENERALLY KEPT POPS IN THE CHANCE CATEGORY THROUGH THE
PERIOD AT THIS TIME DUE TO UNCERTAINTY. WITH THE H850 TEMPERATURES
REACHING -12C AND NORTHWEST FLOW...HIGH TEMPERATURES COULD BE 10
DEGREES BELOW NORMAL TUESDAY.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA AND HRRR AND NAM MODEL OUTPUT,
EXPECT POST SYSTEM TROWAL-RELATED/SO-CALLED WRAP AROUND/ MVFR
STRATOCUMULUS AND LIGHT PRECIPITATION TO AFFECT THE UPPER OHIO
VALLEY INTO LATE AFTERNOON. BRIEF IFR RESTRICTIONS MAY OCCUR THIS
MORNING, BUT LACK SUFFICIENT CONFIDENCE TO PINPOINT ITS OCCURRENCE.
EXPECT PRECIPITATION TYPE TO BE MAINLY DRIZZLE, ALBEIT BRIEF SNOW
FLURRIES CANNOT BE RULED OUT. NAM MODEL PROFILES SHOW CLOUD TOPS
GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION. HOWEVER, RECENT
SATELLITE DATA DOES SHOW SOME HIGHER COLDER CLOUDS PASSING OVER
THE SHALLOW WARMER CLOUDS, SO SOME SEEDER FEEDER ICE NUCLEATION
MAY OCCUR THIS MORNING.
FAST FLOW ALOFT WILL MIX DOWN TO PROMOTE SURFACE WIND GUSTS OF 25
KTS TODAY. WINDS WILL SUBSIDE AT SUNDOWN, WHEN REMAINING CLOUD
CEILINGS WILL LIKEWISE DISSIPATE.
OUTLOOK...THURSDAY THROUGH SUNDAY....
MAINLY VFR. ONLY POTENTIAL FOR RESTRICTIONS CAN BE EARLY MORNING FOG
THURSDAY RELATED TO A SHALLOW SURFACE TEMPERATURE INVERSION, AND
POSSIBLE SHOWERS NEAR I-80 FRIDAY NIGHT WITH A COLD FRONT PASSING
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER CO
231 PM MST WED NOV 30 2011
.SHORT TERM...MAIN CONCERN WILL BE UPCOMING WINTER STORM WITH
POSSIBLE SNOW AMOUNTS AND STRENGTH OF THE NORTHERLY WINDS. THE STORM
SYSTEM CAN BE SEEN DEVELOPING OVER THE GREAT BASIN AND IS DIGGING TO
THE SOUTH AND SOUTHEAST TOWARDS SOUTHERN NEVADA. LATEST RUC QG
HEIGHT TENDENCY FIELDS SHOWING THE BEST FALLS ACROSS SOUTHERN NEVADA
AND THIS TRENDS LOOKS TO CONTINUE TONIGHT UNTIL THE LOW BOTTOMS OUT
ACROSS THE CALIFORNIA AND ARIZONA THURSDAY MORNING. THIS TRACK WILL
TAKE THE STRONGEST UPWARD FORCING ACROSS UTAH WITH LESS FORCING AS
YOU MOVE EAST ACROSS COLORADO. SOME WEAK UPSLOPE ALREADY DEVELOPING
OVER EAST COLORADO WITH CYCLOGENESIS ACROSS SOUTHEAST COLORADO.
HOWEVER IT IS QUITE DRY IN THE LOW LEVELS WITH DEWPOINTS IN THE
SINGLE DIGITS AND TEENS AND WILL TAKE A WHILE TO MOISTEN UP. THE
MAIN PRESSURE RISE IS STILL OVER NORTHERN WYOMING SO THIS SHOULD
BRING THE MAIN FRONT INTO DENVER AROUND 03-04Z. BASED ON UPSTREAM
OBSERVATIONS THERE IS A 2-3 HOUR LAG OF THE SNOW STARTING BEHIND THE
FRONT. AIRMASS SHOULD BECOME SATURATED AROUND 09Z AT DENVER AND A
LITTLE LATER OVER OUR SOUTHERN BOUNDARIES AS UPSLOPE DEEPENS. THE
SNOW SHOULD CONTINUE MUCH OF THE DAY WITH A DECREASING TREND OVER
NORTHERN AREAS DURING THE AFTERNOON.
GIVEN LATEST MODEL OUTPUT...ADVISORY AMOUNTS LOOK IN ORDER OVER
MUCH OF THE CWA WHICH HAVE ALREADY BEEN UPDATED IN THE FORECASTS AND
STATEMENTS. SNOW AMOUNTS MAY BE LACKING ACROSS EASTERN ZONE 46 AND
47 ANY MAY BE MORE WIND THEN SNOW. GIVEN THE AMOUNT THIS STILL MAY
CREATE MORE WINDS THAN SNOW BUT STILL MAY CREATE SOME PROBLEMS WITH
SNOW AND WIND. LATEST NAM IS COME DOWN A BIT IN SNOW AMOUNTS A BIT
MORE INLINE WITH GFS/EUROPEAN OUTPUT OF 3-6 INCHES WITH THE HIGHER
AMOUNTS WEST AND SOUTH OF DENVER AND OVER HIGHER EAST SLOPES.
OVERALL THERE IS A SLIGHTLY SLOWER TREND IN SNOW DEVELOPING AND
DELAY THINGS JUST A BIT IN GRIDS.
.LONG TERM...STORM SYSTEM TO BE EXITING THE AREA THURSDAY EVENING
WITH IMPROVING CONDITIONS FROM ROUGHLY NORTH TO SOUTH. DID KEEP A
CHANCE OF LIGHT SNOW FOR MOST OF THE AREA WITH THE HIGHEST POPS
ALONG THE PALMER DIVIDE AND LINCOLN COUNTY. WEAK RIDGE STILL
EXPECTED FRIDAY ALTHOUGH AIRMASS WILL BE COLD. MODEL CROSS SECTIONS
INCREASE MOISTURE OVER THE MOUNTAINS DURING THE AFTERNOON AHEAD OF
THE NEXT WEATHER SYSTEM. SOME WEATHER AND POPS LOOK WARRANTED FOR AT
LEAST ZONE 31 AFTER 18Z. NAM PAINTS SOME LIGHT QPF AND SNOW
ACCUMULATIONS ACROSS THE FAR EASTERN ZONES WHILE THE OTHER MODELS
ARE DRY. WILL MAINTAIN THE DRY FORECAST FOR THE PLAINS. SNOW CHANCES
TO INCREASE ACROSS THE MOUNTAINS FRIDAY NIGHT...WITH PERHAPS A
SLIGHT CHANCE ACROSS THE LOWER ELEVATIONS. NAM AND GFS OFFER
DIFFERENT SOLUTIONS WITH THIS SYSTEM AS IT CROSS THE AREA SATURDAY.
THE GFS SHOWS MORE WIDESPREAD LIGHT SNOW AMOUNTS WHILE THE NAM
LIMITS THE AMOUNTS TO THE PALMER DIVIDE AS WELL AS THE FOOTHILLS AND
MOUNTAINS. GIVEN THE DISCREPENCIES...FEEL CHANCE POPS MOST AREAS
SEEM REASONABLE. BOTH MODELS DO SHOW SURFACE FRONT MOVING SOUTH
ACROSS THE AREA DURING THE MORNING. THIS STORM TO EXIT THE AREA BY
THE EVENING...WITH RIDGE BUILDING OVER THE GREAT BASIN AND NORTHWEST
FLOW ALOFT ACROSS COLORADO. MODELS CONTINUE TO HINT AT ANOTHER
DISTURBANCE MOVING SOUTHEAST ACROSS THE AREA SATURDAY NIGHT AND
MONDAY MORNING. THERE APPEARS TO BE ENOUGH LIFT AND MOISTURE TO KEEP
A SLIGHT CHANCE OF SNOW ACROSS THE AREA. OTHERWISE...A MAINLY DRY
NORTHWEST FLOW ALOFT TO PREVAIL THROUGH WEDNESDAY. WITH THE LACK OF
MOISTURE AND LIFT...TOOK OUT ALL MENTION OF MOUNTAIN SNOW MONDAY
AFTERNOON AND TUESDAY. MODELS HINT AT TROUGH MOVING ACROSS THE AREA
WEDNESDAY WITH AN INCREASE IN MOISTURE. ADDED SOME MOUNTAIN POPS
WITH DRY CONDITIONS ELSEWHERE. TEMPERATURES THROUGH THE EXTENDED TO
BE BELOW NORMAL...THOUGH SOME MODERATION ON EXPECTED ON TUESDAY.
&&
.AVIATION...A COLD FRONT WILL PASS THROUGH DENVER BETWEEN 03-04Z
GIVEN CURRENT TIMING OF FRONT NOW ACROSS NORTHERN WYOMING.
IT WILL TAKE A WHILE TO MOISTEN UP THE AIRMASS SO THERE WILL BE A
2-3 HOUR LAG FROM FROPA TO SNOWFALL AT LOCAL TERMINALS.
IFR AND ILS CONDITIONS EXPECTED TO DEVELOP BY 09Z WITH SNOW AND
BLOWING SNOW. CONDITIONS WILL SLOWLY IMPROVE DURING THURSDAY
AFTERNOON FROM NORTH TO SOUTH. BEST ESTIMATE OF STORM TOTAL SNOW AT
LOCAL TERMINALS IS 3-6 INCHES...WITH THE HIGHER AMOUNTS AT KAPA/KBJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 5 PM MST THURSDAY
FOR COZ033>037-039-040.
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 2 PM MST
THURSDAY FOR COZ038-042>044-048-049.
WINTER STORM WARNING FROM 11 PM THIS EVENING TO 5 PM MST
THURSDAY FOR COZ041-045>047.
&&
$$
SHORT TERM...SENTREKI
LONG TERM....D-L
AVIATION...S-E
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
205 PM EST Wed Nov 30 2011
.SYNOPSIS...
As an occluding surface low moves northeast up the St. Lawrence
Seaway, and a cold front pushes well off the east coast, surface
high pressure is building into the northern Gulf Coast. Around the
noon hour, the surface ridge extended from eastern Texas up into the
western Great Lakes. Temperatures across most of the Gulf Coast
States were in the 40s and 50s, with the coldest readings to the
north, and this was about 10 to 20 degrees below normal. Meanwhile,
water vapor loops indicate a mid-upper level shortwave trough over
Mississippi and Alabama located at the base of the broader longwave
trough along the east coast of the United States. This shortwave
will continue to dig southeast and reach the Atlantic coast by this
evening. Strong subsidence and drier air will arrive behind the
departing shortwave.
&&
.NEAR TERM (Rest of Today and Tonight)...
The focus for the first 18 hours of the forecast was on temperature
trends for tonight, and related frost and freeze concerns. Low
stratus continues to erode early this afternoon, albeit much more
slowly than the models have been willing to indicate. The HRRR has a
very good handle on the current distribution of clouds and it slowly
eats away at the edges of the stratus from near MAI up into eastern
Alabama through the rest of the afternoon. One thing that the HRRR
is an outlier on is showing the remnants of the stratus deck
settling closer to the surface in the evening, and then starting to
expand back into the northwest parts of our forecast area. This is a
possibility, especially with a strengthening subsidence inversion in
the wake of the departing shortwave possibly "trapping the moist
layer" beneath the inversion. However, with no support from other
models we basically extrapolated the current cloud trends to get
mostly clear skies by 06z. If the HRRR ends up being the most
realistic with respect to overnight cloud cover, that would have a
notable impact on low temperatures (keeping things warmer, and
reducing risk of frost).
Since we were operating on the assumption of mostly clear skies, and
with the surface high pressure building in, it would be a good night
for radiational cooling. 12z soundings from KLIX and KJAN to the
west showed a sharp and shallow radiation inversion, and that would
likely be the scenario given clear skies and calm winds. Therefore,
the lows were not changed much from the previous forecast and fall
between 30 and 32 degrees. This is similar to what was observed
upstream in S/C Mississippi this morning, where dewpoints the
preceding afternoon and evening were also in the mid-30s. Therefore,
strong radiational cooling is expected to compensate for dewpoints
initially above freezing. Exceptions to the low temperature forecast
would be upper 20s in the typical cold spots: west of Dothan and the
Choctawhatchee River, the Apalachicola National Forest, the Suwannee
River Valley, and parts of the Chattahoochee River Valley. Thus, we
upgraded the Freeze Watch to a Freeze Warning for all of the area
except for coastal zones from Gulf County around the Big Bend to the
mouth of the Suwannee River (lows forecast in the mid 30s). Frost
was added to the grids as well with the cold temperatures, light
winds, and RH approaching 100% by 12z. We could see a little light
fog, but the visibilities upstream were only about 5-6 miles this
morning in Mississippi, and we are expecting a similar situation
around here. For Tallahassee: forecast lows in the center of the
city are 36-37 degrees, compared to 30 at the airport.
&&
.SHORT TERM (Thursday through Friday Night)...
A quiet weather pattern is in store for the short term period. Clear
skies and highs climbing into the lower to middle 60s regionwide are
expected.
The main forecast challenge is forecasting overnight lows Thursday
night. Although Thursday night is forecast to be warmer than
Wednesday night, the threat still exists for some patchy frost
development near dawn. Expect lows to fall into the middle 30s with
our cooler spots falling into the lower 30s. It is the cooler spots
that will also have the greatest chance for patchy frost
development.
High temperatures will continue to warm on Friday with middle to
upper 60s expected. Overnight lows will moderate into the upper 30s
to lower 40s inland, with upper 40s likely along the coast.
&&
.LONG TERM (Saturday through next Wednesday)...
The extended period will begin with an amplified upper pattern
across the CONUS, consisting of a deep trough and cut-off low over
the four corners region, and a building ridge stretching from the
Gulf of Mexico up the eastern seaboard. The system over the
southwestern states will slowly progress eastward through the period
and bring a front into the deep south by late Monday into Tuesday,
ushering in a shot of cold air for the middle of next week.
Ahead of this system, dry conditions and moderating temperatures are
expected across the forecast area, with easterly flow on Saturday,
becoming onshore by late Sunday into Monday. Temperatures are
forecast to be at, or just slightly above, normal through the
weekend.
A band of showers is expected to accompany the front into the region
beginning Monday and continuing through Monday night. At this time,
it appears the main energy with the system will be shunted northward
by the pre-existing upper ridge, causing the rain to diminish as the
front crosses the forecast area. Instability is forecast to be
minimal or non-existent with no thunderstorms expected.
&&
.MARINE...
With the calm center of the surface ridge sprawling the southeastern
part of the country expected to pass well north of our forecast
area, winds and seas will refrain from subsiding too much over the
next several days. In fact, as the ridge continues to move east, our
forecast waters will fall under a more easterly flow regime. This
regime is favorable for nocturnal east to west surges in both winds
and seas. These surges will begin Thursday night and continue
through the first part of the weekend, gradually getting stronger
each night. Winds, and possibly seas, reach cautionary levels by
Friday night and could require an advisory by Saturday night.
&&
.AVIATION...
Low stratus took longer to erode this morning than models had
originally forecast. In fact, alternate fuel impacts (1600 ft CIG)
are still occurring at DHN, with the low ceilings scattered out at
the remainder of the four terminals. The HRRR model represented the
current cloud cover well, so that was used to time the low clouds
through 00z. With a surface ridge settling into the region tonight,
the winds should become calm (or nearly calm) at all of the
terminals. We expect a similar evolution to what happened upstream
in Mississippi this morning, when light fog (5-6SM visibility)
developed after midnight. We kept things in the VFR range for now,
but all of the terminals include a "6SM BR" group towards dawn.
&&
.FIRE WEATHER...
Although minimum RH will fall to between 30-35% over much of the
area tomorrow afternoon, no other criteria are expected to be met
for red flag conditions in our Florida zones. Dispersions may
approach 70 in the eastern Big Bend, but this is coincident with the
area of highest forecast RH. The minimum RH falls slightly again
into Friday, but with light winds no red flag conditions are
expected. More east-southeasterly flow this weekend will finally
increase low level humidity.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 30 64 34 68 41 / 0 0 0 0 0
Panama City 33 63 42 67 47 / 0 0 0 0 0
Dothan 31 62 36 66 39 / 0 0 0 0 0
Albany 30 63 33 66 38 / 0 0 0 0 0
Valdosta 31 64 35 67 42 / 0 0 0 0 0
Cross City 31 68 38 72 44 / 0 0 0 0 0
Apalachicola 35 62 43 66 48 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Freeze Warning from 2 AM to 8 AM CST Thursday for Coffee-Dale-
Geneva-Henry-Houston.
GA...Freeze Warning from 3 AM to 9 AM EST Thursday for Baker-Ben Hill-
Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-Decatur-Dougherty-
Early-Grady-Irwin-Lanier-Lee-Lowndes-Miller-Mitchell-
Quitman-Randolph-Seminole-Terrell-Thomas-Tift-Turner-Worth.
FL...Freeze Warning from 3 AM EST /2 AM CST/ to 9 AM EST /8 AM CST/
Thursday for Calhoun-Central Walton-Coastal Bay-Gadsden-
Holmes-Inland Bay-Inland Dixie-Inland Franklin-Inland Gulf-
Inland Jefferson-Inland Taylor-Inland Wakulla-Inland Walton-
Jackson-Lafayette-Leon-Liberty-Madison-South Walton-
Washington.
GM...None.
&&
$$
Long Term...Camp
Short Term/Marine...Harrigan
Synopsis/Near Term/Aviation/Fire Weather...Lamers
AREA FORECAST DISCUSSION
NWS TOPEKA KS
335 PM CST WED NOV 30 2011
.DISCUSSION...
SHORT RANGE FORECAST (TONIGHT AND THURSDAY)...
20Z WATER VAPOR IMAGERY AND ASSOCIATED 500 MB RUC ANALYSIS SHOWS A
MID/UPPER LEVEL TROUGH OVER THE APPALACHIAN MOUNTAINS...WITH ANOTHER
H5 LOW DIVING SOUTHWARD THROUGH THE NORTHERN ROCKIES. BETWEEN THE
TWO TROUGHS IS A FLATTENED UPPER RIDGE OVER THE CENTRAL PLAINS WHICH
HAS BROUGHT FAIR CONDITIONS TO THE AREA. SOUTHERLY FLOW ALONG THE
EASTERN EDGE OF A DEEPENING SURFACE TROUGH ADVECTED WARM AIR INTO
NORTHEAST KANSAS...ALLOWING TEMPS TO REACH THE MID 50S ACROSS MUCH
OF THE AREA. EXPECT THE SURFACE TROUGH TO PUSH SOUTHEASTWARD AHEAD
OF AN ADVANCING SURFACE RIDGE...WHICH WILL BRING A COLD FRONT
THROUGH THE AREA BY MID DAY ON THURSDAY. EXPECT COOLER/DRYER AIR TO
MOVE IN BEHIND THE COLD FRONT FOR THURSDAY...ESPECIALLY FOR AREAS
ACROSS NORTH CENTRAL KANSAS WHICH WILL SEE THE FRONTAL PASSAGE
BEFORE PEAK HEATING. AREAS OF EASTERN KANSAS MAY SEE ANOTHER MILD
DAY AS SOUTHERLY FLOW SHOULD PERSIST THROUGH MUCH OF THE EARLY
AFTERNOON BEFORE THE FRONTAL PASSAGE IN THE EARLY EVENING. EXPECT
STRATUS TO BUILD IN BEHIND THE FRONT WHICH COULD POSSIBLY BRING SOME
SCATTERED SPRINKLES OR POSSIBLY SOME SNOW FLURRIES TO AREAS OF NORTH
CENTRAL KANSAS ON THURSDAY.
LEIGHTON
LONG TERM...THU NIGHT THROUGH NEXT WEDS.
FCST FOCUS REMAINS ON THE EVOLUTION OF STORM SYSTEM FRI INTO SAT.
RECENT MODEL GUIDANCE AND TRENDS CONTINUE TO SUGGEST A SLOWER
TRACK THAN THAT INDICATED BY THE NAM. GFS/ECMWF ARE THE FAVORED
MODELS FOR THIS FCST.
INITIAL MODIFIED POLAR AIRMASS WILL SETTLE INTO THE AREA THU
NIGHT WITH LIGHT WINDS AND SEASONABLY COLD TEMPS. BY FRI
AM...SOUTHERLY SFC WINDS WILL DEVELOP AS THE WESTERN U.S. LONGWAVE
TROUGH BEGINS TO BECOME PROGRESSIVE. LIFT WILL INCREASE THROUGH
THE DAY WITH SATURATION AND PRECIP DEVELOPMENT EXPECTED BY FRI
NIGHT. THERMAL PROFILES SUGGEST MAINLY RAIN EXCEPT FOR THE
NORTHWEST THIRD OF THE CWA WHERE DEPENDING ON THE WET BULB TEMPS
THERE MAY BE A RISK FOR FREEZING RAIN. GFS RAW MODEL NEAR SFC
TEMPS ARE WARMER THAN THE NUMERICAL MODEL GUIDANCE WHICH SUGGESTS
LOWS IN THE UPPER 20S TO LOWER 30S ACROSS THE NW THIRD SO
CONFIDENCE IN ICE THREAT REMAINS LOW AT THIS TIME. RIGHT NOW AREAS
ROUGHLY FROM ABILENE TO SENECA AND NW COULD SEE FREEZING PRECIP
FRI NIGHT. GFS CONTINUES TO WARM BOUNDARY LAYER TEMPS UP EARLY SAT
SUCH THAT ANY FZRA/ICE RISK SHOULD DECREASE HOWEVER WIDESPREAD
RAIN...SOME HEAVY SHOULD PERSIST ACROSS THE AREA AS THE UPPER
TROUGH MOVES THROUGH THE AREA AND THE SFC LOW TRACKS ACROSS
EASTERN KS. PRECIP SHOULD MIX WITH OR CHANGE TO SLEET OR SNOW FROM
WEST TO EAST BY LATER SAT/SAT NIGHT AS COLDER AIR ARRIVES ON THE
BACK SIDE OF THE SYSTEM. HOWEVER GFS ALSO SHOWS A DRY SLOT LATER
SAT AFTERNOON WHICH COULD BRING A BREAK IN THE PRECIP AND WOULD
ALSO LIMIT THE SNOW THREAT ACROSS NORTH-CENTRAL KS.
ALL IN ALL...LOOK FOR ANOTHER ROUND OF WIDESPREAD HEAVY RAINS OF 1
TO 2.5 INCHES FRI NIGHT INTO SAT WITH WHAT APPEARS TO BE A LOW RISK
FOR FREEZING PRECIP FRI NIGHT ACROSS PARTS OF THE AREA.
THE PATTERN LOOKS QUITE ACTIVE FOR THE REGION INTO NEXT WEEK WITH
ADDITIONAL POLAR COLD FRONTS EXPECTED TO DRIVE SOUTHWARD THROUGH
THE PLAINS. THE ACTUAL LONGWAVE TROUGH AXIS MAY NOT PASS THROUGH
THE REGION UNTIL MID WEEK SO CLOUDS/SOME LOW PRECIP CHCS MAY
LINGER ACROSS SOUTHERN KS BUT IT LOOKS DRY BUT COLD ACROSS NE KS.
CO
&&
.AVIATION...
VFR CONDITIONS PERSIST THROUGH THE NEXT 24 HOUR PERIOD. STEEP
SFC PRESSURE GRADIENT OVER KMHK AND THE HIGHER ELEVATION OVER
KFOE WILL INCREASE SOUTHERLY WIND GUSTS OVER 20 KTS WEDNESDAY
AFTERNOON.
BOWEN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
312 PM CST WED NOV 30 2011
.DISCUSSION...
TONIGHT THROUGH THURSDAY...AT THE SFC A WEAK COLD FRONT WILL
SLOWLY GLIDE S ACRS SRN MN/SW WI THROUGH THE OVERNIGHT HOURS INTO
THU MRNG. AS IT DROPS S...A RELATIVELY WEAK AREA OF LOW PRESSURE
IS EXPECTED TO DEVELOP ALONG IN INVOF MN/IA BORDER. FAIRLY DEEP
MOISTURE...AS SHOWN BY AN EXTENSIVE CLOUD SHIELD ON VIS SAT
IMAGERY AND RATHER MOIST RUC SOUNDINGS...IS AVAILABLE FOR A DECENT
MIDLVL SHORTWAVE TROUGH AXIS TO PRODUCE PRECIP MAINLY AFTER
MIDNIGHT AND THROUGH SUNRISE. TAKING THE FORM OF ALL SNOW... WILL
LOOK FOR ENOUGH QPF TO PRODUCE ONE HALF TO ONE AND A HALF INCHES
OF SNOW WITH THE HEAVIEST OF THE SNOW OCCURRING DURING THE MORNING
COMMUTE HOURS. THE GREATER OF THE SNOW ACCUMULATIONS WILL EAST AND
SOUTH OF THE TWIN CITIES METRO. ALTHOUGH CONVECTIVE SNOWS ARE NOT
APPARENT ON EVEN SHORT-TERM MODELS PARTICULARLY WITH SFC
CONVERGENCE AND LIFT RATHER WEAK...THE UPPER LEVEL SUPPORT
AVAILABLE DOES NOT RULE OUT AN ISOLATED BURST OF HEAVIER SNOW THAT
COULD PRODUCE UP TO 2 INCHES IN A SHORT AMOUNT OF TIME...MAINLY
OVER WRN WI WHERE JET DYNAMICS LOOK TO POTENTIALLY ENHANCE PRECIP
THURSDAY MORNING. THE PRECIP WILL GRADUALLY TAPER OFF DURING THE
LATE MORNING THROUGH AFTERNOON HOURS TOMORROW WITH VERY LITTLE
LEFT BY LATE AFTERNOON. AS FOR TEMPERATURES...THE POTENT COLD
FRONT WILL EFFICIENTLY LEAD THE WAY FOR H85 TEMPS IN THE -7 TO -10
DEG C RANGE TO DROP THROUGH THE REGION DURING THE DAY TOMORROW...
MAKING FOR A VERY SMALL DIURNAL RANGE FROM LOW TEMPS TONIGHT TO
HIGHS TMRW. LOWS TONIGHT WILL RANGE FROM THE LWR 20S NW TO AROUND
30 SE AND IN THE METRO...FOLLOWED BY HIGHS THU FROM THE MID 20S NW
TO THE LWR 30S SE.
THURSDAY NIGHT THROUGH SUNDAY...SKIES WILL SLOWLY CLEAR OUT THU
NIGHT INTO FRI THE UPPER LEVEL TROUGH DROPS S OF THE REGION AND A
BUBBLE HIGH PRES RIDGE MOVES ACROSS THE NRN PLAINS INTO THE GREAT
LAKES. AT THE SFC...A SPOKE OF HIGH PRES EXTENDING NE FROM THE
CENTRAL PLAINS WILL ROTATE THROUGH...ALLOWING FOR DECENT
RADIATIONAL COOLING CONDITIONS THU NIGHT AS WINDS DROP TO BELOW 7
MPH. LOWS WILL FALL TO THE UPPER SINGLE DIGITS TO THE MID TEENS.
EVEN WITH THE CLEAR SKIES CONTINUING ON FRI AND SFC FLOW TURNING
MORE SLY...NW TO W UPPER FLOW AND H85 TEMPS ARND -5 DEG C WILL
KEEP HIGHS ON FRI JUST BELOW FREEZING. THE WEATHER STORY BECOMES
VERY INTERESTING FRI NIGHT THROUGH SAT NIGHT AS AS UPPER LEVEL LOW
CHURNING IN THE SOUTHWEST BECOMES CAUGHT UP IN A NORTHERN STREAM
LONGWAVE TROUGH AXIS PUSHING THRU WRN CANADA AND THE NRN PLAINS
STATES. BOTH UPPER SYSTEMS INTERACT BUT IN PIECES...AND A FEW
PIECES OF ENERGY WILL SHIFT NE FROM THE SOUTHWEST TWD THE GREAT
LAKES SAT AS CYCLOGENESIS OCCURS OVER THE TX PANHANDLE. THIS
NEWLY-GENERATED SFC LOW WILL RACE NE LATE SATURDAY THROUGH SAT
NIGHT BUT THE BIGGER PROBLEM IS HOW CLOSE AN UPPER SHORTWAVE
TROUGH AXIS COMES TO INTERACT WITH IT. MOISTURE TRANSPORT AHEAD OF
THIS NEW SFC LOW INCREASES AND THE INCOMING UPPER TROUGH WILL
ENHANCE LIFT. GIVEN THE COLD TEMPERATURES IN PLACE...P-TYPE ISSUES
WILL NOT BE PRESENT FOR THE WFO MPX CWFA AS PRECIP WOULD BE ALL
SNOW. THERE IS STILL MUCH MODEL DISAGREEMENT IN THE PLACEMENT OF
THE MAIN PLAYERS INVOLVED...AND THIS IS RELAYED VIA MODEL SNOWFALL
ACCUMS WHICH COULD BE UP TO A COUPLE OF INCHES TO OVER 6 INCHES
WITH THE HIGHEST AMOUNTS FOR SOUTHERN AND EASTERN PORTIONS OF THE
COVERAGE AREA. HAVE NUDGED POPS INTO THE LIKELY CATEGORY FOR THOSE
AREAS...TRENDING DOWN GOING WEST AND NORTH...AND HAVE KEPT
SNOWFALL AMOUNTS CAPPED AT 4 INCHES FOR FAR SRN AND ERN FRINGES
WITH NO SNOW EXPECTED FOR THE NWRN TIERS. THIS SYSTEM QUICKLY
EJECTS TO THE E SAT NIGHT INTO SUN...ALLOWING FOR AT LEAST PARTIAL
CLEARING DURING THE DAY SUNDAY BEFORE ANOTHER AREA OF LOW PRESSURE
DROPS IN FROM MANITOBA LATE SUN INTO SUN NIGHT. THERE IS POTENTIAL
FOR VERY LIGHT ACCUMS OVER NRN TIERS OF THE COVERAGE AREA BUT WITH
SO MUCH UNCERTAINTY WITH THIS SATURDAY SYSTEM...IT IS DIFFICULT TO
PINPOINT THINGS WITH THE LATE SUNDAY SYSTEM SO HAVE KEPT POPS IN
THE SLGT CHC CATEGORY. TEMPERATURES WILL RUN NEAR TO SLIGHTLY
ABOVE NORMAL THRU FRI...THEN DROP TO SLIGHTLY BELOW NORMAL OVER
THE WEEKEND.
MONDAY THROUGH WEDNESDAY...THE AFOREMENTIONED LOW ON SUNDAY WILL
MOVE INTO THE GREAT LAKES MONDAY...FOLLOWED BY RIDGING BOTH AT THE
SFC AND ALOFT FOR THE START OF NEXT WEEK. COLDER PUNCHES OF AIR
DROPPING S FROM NRN-CENTRAL CANADA WILL KEEP TEMPS BELOW NORMAL
FOR THE FIRST HALF OF NEXT WEEK. HAVE KEPT A PREDOMINANTLY DRY
FORECAST GOING DUE TO THE LACK OF BONA FIDE SYSTEMS PROGGED FOR
THIS PERIOD.
&&
.AVIATION.../18Z TAF ISSUANCE/
A BUSIER FORECAST PERIOD IS IN STORE FOR AVIATION CONCERNS IN
COMPARISON TO THE PAST MANY DAYS. AN SHORTWAVE TROUGH CURRENTLY
MOVING THROUGH THE NORTHERN ROCKIES WILL SWING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST LATER TODAY AND TONIGHT... PUSHING A COLD
FRONT ACROSS OUR AREA TONIGHT INTO EARLY THURSDAY. A BAND OF LIGHT
TO MODERATE PCPN IS EXPECTED TO ACCOMPANY THE PASSAGE OF THESE
SYSTEMS... WITH MORE WIDESPREAD PCPN DEVELOPING AS THE SYSTEM
MOVES SOUTHEAST THROUGH THE AREA AND THE ATMOSPHERE HAS MORE TIME
TO SATURATE. A LOWERING IN CEILINGS WILL CONTINUE THIS AFTERNOON
INTO TONIGHT... WITH MVFR CONDITIONS LIKELY DEVELOPING PRIOR TO
PCPN ARRIVAL... AND LOWER MVFR AND POSSIBLE IFR CEILINGS DURING
THE PCPN. MOST PCPN SHOULD BE IN THE FORM OF SNOW... ALTHOUGH SOME
MIX WITH RAIN OR FREEZING DRIZZLE IS POSSIBLE OVER THE
NORTHWESTERN PORTION OF THE FORECAST AREA AT THE ONSET. HOWEVER...
THAT POSSIBILITY IS SUFFICIENTLY LOW TO LEAVE IT OUT OF THE
FORECAST FOR THAT AREA. CONDITIONS SHOULD IMPROVE FAIRLY QUICKLY
IN THE WAKE OF THE SYSTEM TOMORROW MORNING... WITH VFR CONDITIONS
DEVELOPING BY MID TO LATE MORNING ACROSS MOST OF THE AREA.
KMSP... TAF REFLECTS EXPECTATIONS OF THE EVOLUTION OF CEILINGS AND
VISIBILITIES GOING FROM VFR TO MVFR WITH SOME IFR POSSIBLE. SHOULD
GET A BETTER HANDLE ON THE POSSIBILITY OF LOWER CEILINGS AND/OR
VISIBILITIES ONCE THINGS START TO COME TOGETHER UPSTREAM LATER
THIS AFTERNOON AND THIS EVENING. TIMING UNCERTAINTY ON THE WORST
CONDITIONS COULD VARY BY +/- 1-3 HOURS... WITH SOME POSSIBILITY OF
SUB-1000FT CEILINGS AND SUB 1 MILE VISIBILITIES... PARTICULARLY
BETWEEN 09Z AND 12Z.
//OUTLOOK FOR KMSP FOR THURSDAY NIGHT THROUGH SUNDAY//
THURSDAY NIGHT...VFR CONDITIONS EXPECTED.
FRIDAY...VFR CONDITIONS EXPECTED.
FRIDAY NIGHT...VFR CONDITIONS EXPECTED.
SATURDAY...MVFR CEILINGS POSSIBLE. CHANCE OF SNOW LATE.
SATURDAY NIGHT...MVFR CEILINGS EXPECTED... IFR CEILING POSSIBLE.
MVFR VISIBILITIES POSSIBLE. CHANCE OF SNOW.
SUNDAY...MVFR CEILINGS POSSIBLE EARLY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC/TRH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
346 PM EST WED NOV 30 2011
.SYNOPSIS...
A NORTHWEST FLOW OF COOLER AIR LATE THIS AFTERNOON WILL BRING
SCATTERED RAIN AND SNOW SHOWERS TO THE AREA TIL EARLY EVENING.
HIGH PRESSURE WILL BUILD INTO THE REGION LATE TONIGHT AND REMAIN
IN THE VICINITY THROUGH THURSDAY NIGHT. A WEAK COLD FRONT IS
EXPECTED TO CROSS THE AREA ON FRIDAY BRINGING THE NEXT CHANCE FOR
RAIN AND POSSIBLY SNOW SHOWERS.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
H5 TROF AND ASSOCIATED SFC FEATURE WILL MOVE EAST OF THE REGION
BY EARLY EVENING. SCATTERED RAIN/SNOW SHOWERS WILL CONTINUE
PRIMARILY ACROSS THE NRN CWA TIL EARLY EVENING. CONDITIONS
OVERNIGHT NOT FAVORABLE FOR LAKE EFFECT PRECIP DUE TO MID LEVEL
WARMING BEGINNING AT 00Z ALONG WITH VERY DRY AIRMASS UPSTREAM.
ALTHOUGH NORTHWEST FLOW MAY KEEP SKIES PARTLY CLOUDY ACROSS MUCH
OF CENTRAL NEW YORK UNTIL DAYBREAK.
OVERNIGHT LOWS WILL RANGE FROM THE MID 20S TO AROUND 30.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY THROUGH THURSDAY NIGHT...SFC HIGH PRES WILL STRETCH FROM
THE TN VALLEY NORTHEAST INTO NEW ENGLAND BRINGING MAINLY CLEAR
SKIES TO THE REGION ALONG WITH TEMPS NEAR SEASONAL LEVELS.
FRIDAY...WEAK NORTHERN STREAM MOISTURE STARVED SFC TROF WILL DROP
ACROSS THE REGION BRINGING THE CHANCE FOR RAIN SHOWERS ESPECIALLY
OVER THE NRN PTN OF THE CWA. BOUNDARY LAYER TEMPS BY LATE
AFTERNOON MAY BE COLD ENOUGH FOR A RAIN/SNOW SHOWER MIX. MAXES
WILL GENERALLY RANGE IN THE LOWER TO MIDDLE 40S.
FRIDAY NIGHT...ONCE AGAIN EVEN BEHIND A SFC TROF CONDITIONS ARE
NOT FAVORABLE FOR LAKE EFFECT SNOW. SFC HIGH PRES BUILDS IN
QUICKLY BEHIND THE FRONT RESULTING IN VERY WEAK FLOW ALONG WITH MODERATING
T85 DURING THE OVERNIGHT PERIOD. SKIES WILL BECOME MAINLY CLEAR TO
PARTLY CLOUDY WITH LOWS IN THE MID TO UPPER 20S.
SATURDAY...A STRONG UPPER LEVEL RIDGE BUILDS OVER THE NORTHEAST,
ACTUALLY MUCH STRONGER THAN DEPICTED BY THE MODELS YESTERDAY, AS
SFC HIGH PRES MOVES TO THE EASTERN SEABOARD. THIS WILL RESULT IN
MOSTLY SUNNY SKIES ALONG WITH TEMPS MODERATING INTO THE MID/UPPER 40S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AN UPPER LEVEL RIDGE WILL SLOWLY PUSH TO THE EAST SUNDAY AS A SW
TROUGH AND A SFC LOW MOVE FROM THE CENTRAL PLAINS TO THE NORTHEAST,
JUST SOUTH OF THE HUDSON BAY BY SUNDAY AFTERNOON. A COLD FRONT WILL
APPROACH THE CWA SUNDAY EVENING AND BRING A CHANCE OF RAIN TO THE
CWA. THE FRONT LOOKS TO STALL JUST EAST OF THE CWA. THIS SHOULD KEEP
MOST OF THE COLDER AIR TO THE WEST, ALLOWING FOR THE PRECIPITATION
TO BE RAIN. HOWEVER, THERE IS A CHANCE ENOUGH COLD AIR MOVES IN FOR
EITHER A MIX OF A CHANGE OVER TO SNOW, ESPECIALLY IN HIGHER
ELEVATIONS. THE FRONT MOVES VERY LITTLE FOR THE REMAINDER OF THE
EXTENDED FORECAST PERIOD, KEEPING A MENTION OF PRECIPITATION THROUGH
WEDNESDAY.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
UPR LVL TROF AND ASSCD 2NDRY SFC TROF CRNTLY WORKING ACRS THE
FCST AREA. AREAS OF MVFR CIGS/VSBY`S WITH -SHRA/-SHSN...MOST
WDSPRD ACRS CNTRL NY...WILL PERSIST INTO THE EVNG HRS. DIFFS IN
THE MDLS W/RESPECT TO THE TIMING OF CLEARING TNGT...WITH CRUDE
EXTRAPOLATION SUPPORTING THE SLOWER RUC SCENARIO. HOWEVER...WE
THINK THE INDICATION OF MVFR CIGS PERSISTING WELL INTO THE OVRNGT
HRS AT PLACES LIKE ITH/BGM/AVP IS OVERDONE BY THE RUC. WE LEANED
TWDS A COMPROMISE WHICH SUGGESTS CLEARING OR PARTIAL CLEARING AT
MOST SPOTS IN THE 03-06Z TIME FRAME. AFTER THIS MSTR LIFTS
OUT..XPCT SCT-BKN HI CLDS ON THU. WINDS THIS AFTN AHEAD OF THE SFC
TROF SWLY 10-20 KTS...BECMG W TO NW 10-20 KTS BEHIND THE TROF.
WINDS SUBSIDING TNGT TO 5-10 KTS...THEN WRLY ON THU ARND 10 KTS.
OUTLOOK...
THURSDAY NIGHT...VFR.
FRIDAY...BRIEF PD OF MVFR PSBL ACRS CNTRL NY DUE TO CDFNT AND SCT
-SHRA.
FRI NGT/SATURDAY/SUNDAY...VFR.
MON...MVFR/IFR AS RAIN DVLPS ACRS THE AREA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RRM
NEAR TERM...RRM
SHORT TERM...RRM
LONG TERM...SLI
AVIATION...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1247 PM EST WED NOV 30 2011
.SYNOPSIS...
A DISTURBANCE IN THE UPPER ATMOSPHERE WILL BRING SCATTERED SHOWERS
TO THE AREA TODAY. THE BEST SHOT AT PRECIPITATION WILL COME THIS
AFTERNOON. SOME WET SNOW MAY MIX WITH THE RAIN. A FEW SNOW SHOWERS
ARE POSSIBLE EARLY TONIGHT OTHERWISE HIGH PRESSURE WILL BRING A
RETURN TO DRY WEATHER WHICH WILL LAST THROUGH THURSDAY. ANOTHER
WEAK DISTURBANCE WILL BRING THE NEXT CHANCE OF PRECIPITATION
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
12 PM UPDATE...SURFACE TROF NOW ENTERING THE WESTERN PTN OF CWA.
SCATTERED RAIN/SNOW SHOWERS ARE OCCURRING BEHIND BOUNDARY WHICH
AGREES WITH CURRENT FORECAST, NO SIGNIFICANT CHANGES OTHER THAN
MINOR TEMP/POP ADJ.
10 AM UPDATE...SFC LOW CURRENTLY OVER SOUTHERN QUEBEC WITH SFC
TROF BACK ACROSS EXTREME WESTERN NEW YORK. FRONTAL MOISTURE/LIFT
COMBINED WITH COLD CORE ALOFT THIS AFTERNOON WITH MAKE FOR
SCATTERED RAIN SHOWERS THIS AFTERNOON ACROSS CENTRAL NEW YORK.
BOUNDARY LAYER TOO WARM THROUGH MIDDAY FOR SNOW SHOWERS. AFTER 18Z
CAA BEHIND TROF WILL DROP TEMPS ENOUGH FOR A RAIN/SNOW SHOWER MIX
WITH CONDITIONS MORE FAVORABLE BY MID/LATE AFTERNOON. JUST MINOR
TWEAKS OF POPS/TEMPS.
615 AM UPDATE...AREA OF RAIN FROM THIS MORNING HAS ALMOST MOVED
OUT OF THE AREA. KEPT POPS FOR ANOTHER HOUR OR TWO ACROSS THE FAR
NORTH AND EAST...OTHERWISE REMOVED POPS TO EMPHASIZE THE LULL IN
PRECIP. EXPECTED NOW THROUGH MIDDAY. CONTINUED TO SHOW INCREASING
CHANCES FOR RAIN OR SNOW LATER TODAY AS THE COLD CORE ALOFT MOVES
OVERHEAD AND WE GET INTO THE BACKSIDE OF THE UPPER LOW. PREVIOUS
AFD IS BELOW.
4 AM UPDATE...THE COLD FRONT WHICH BROUGHT US STEADY RAIN
LAST NIGHT HAS MOVED TO OUR NORTHEAST. BEHIND THE FRONT WE ARE NOW
BEING IMPACTED BY THE UPPER LEVEL LOW NOW MOVING INTO WESTERN NY.
A GOOD SHOT OF RAIN IS MOVING THROUGH THE CENTRAL PART OF THE CWA
NOW...JUST AHEAD OF THE UPPER LOW. MOST OF THIS PRECIP. THIS
MORNING WILL FALL IN THE FORM OF RAIN. HOWEVER BACK TO THE
WEST...CLOSER TO THE COLDER AIR ALOFT...SOME WET SNOW MAY MIX IN
PRIOR TO DAYBREAK OVER THE WESTERN SOUTHERN TIER. THIS WILL BE
ESPECIALLY TRUE OVER THE HIGHER TERRAIN AS EVIDENT BY WELLSVILLE
NOW REPORTING SOME MIXED PRECIP AT LAST OB. IN FACT OUR RADAR IS
SHOWING A NICE BRIGHT BANDING FEATURE NOW AS THE STEADIER
PRECIPITATION MOVES CLOSE TO THE RADAR (KBGM) WITH FREEZING LEVELS
BEING BETWEEN 2500 AND 4000 FEET.
WE SHOULD SEE A LULL IN THE PRECIPITATION BEYOND EARLY THIS
MORNING WITH ALL MODELS INDICATING THAT AS OUR STEADY AREA OF RAIN
LIFTS NORTHEAST...IT WILL FALL APART AS WE LOSE UPPER LEVEL
SUPPORT. YOU CAN LOOK AT SW NY AND NW PA NOW AS A GOOD PICTURE OF
WHAT MOST OF TODAY WILL LOOK LIKE THROUGH EARLY AFTERNOON.
EVENTUALLY LATER TODAY AS THE UPPER LOW MOVES NORTH...WE WILL
BEGIN TO SEE WRAP AROUND PRECIP MOVE BACK INTO THE AREA. 850 TEMPS
COOL TO BETWEEN -3C AND -6C DURING THIS TIME WHICH SHOULD SUPPORT
A GRADUAL TRANSITION TO WET SNOW. BOUNDARY LAYER TEMPS WILL KEEP
ANY ACCUMS LIMITED TO A COATING ACROSS THE HIGHER TERRAIN.
TONIGHT WRAP AROUND MOISTURE WILL QUICKLY DIMINISH BUT JUST ENOUGH
COOL AIR WILL EXIST FOR A SHORT WINDOW OF LAKE EFFECT SNOW
SHOWERS EARLY THIS EVENING. THE LIMITING FACTORS WILL BE THE SHORT
DURATION OF THE FAVORABLE CONDITIONS (LAKE DELTA T`S NEAR 14 AND A
NORTHWEST FLOW)...AND AN INVERSION UNDER 850 MB. CONTINUED A
SLIGHT CHANCE FOR SNOW SHOWERS ACROSS THE NORTHERN HALF OF THE CWA
EARLY THIS EVENING TO ACCOUNT FOR THIS BEFORE DRYING OUT RAPIDLY.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
4 AM UPDATE...HIGH PRESSURE CONTROLS OUR WEATHER THURSDAY WITH DRY WEATHER
EXPECTED. SKIES SHOULD BE FAIRLY SUNNY BUT A FEW EXTRA CLOUDS WILL
BE POSSIBLE FROM THE FINGER LAKES NORTHWARD AS WAA WILL HELP TO
CREATE SOME MID LEVEL CLOUDS. NEXT SYSTEM ARRIVES IN THE FORM OF A
COLD FRONT FRIDAY. STILL A FAIR AMOUNT OF UNCERTAINTY WITH HOW
MUCH OF AN IMPACT THIS FRONT HAS IN OUR AREA IN TERMS OF
PRECIPITATION. THE NAM SHOWS NO QPF IN OUR AREA AS THE FRONT MOVES
THROUGH...WHILE THE EURO...THE WETTEST OF THE MODELS...STILL SHOWS
LESS THAN A TENTH OF AN INCH. THE GFS IS IN THE MIDDLE. CONTINUED
TO SIDE WITH THE EURO...WHICH HPC GUIDANCE SUPPORTS...AND IS IN
LINE WITH OUR CURRENT FORECAST. THE OTHER DIFFICULT PART OF THE
FORECAST IS PTYPE WITH THE WETTER EURO SOLUTION ALSO BEING THE
COLDER OF THE MODELS. DECIDED TO WORD THE FORECAST RAIN OR SNOW
FRIDAY AND LOW MAX T`S A BIT TO BE IN LINE WITH THE PTYPE
FORECAST. 850S ON THE EURO ARE BETWEEN -3C AND -6C...AND 925S ARE
NEAR 0C OR JUST BELOW...WHICH SHOULD SUPPORT FLAKES ESPECIALLY AS
YOU GET RIGHT OUT OF THE VALLEYS THEMSELVES. WE ARE STILL TALKING
ABOUT A VERY LOW QPF EVENT AND WITH TEMPS ABOVE FREEZING...NOT
EXPECTING MUCH.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
1 AM UPDATE...
LITTLE CHANGE. MODELS STILL CLOSE TO EACH OTHER AND PREVIOUS RUNS.
DRY AND MILD AT THE START WITH A SURFACE HIGH SAT AND SAT NGT,
THEN A SLOW MOVING COLD FRONT AND RAIN CHANGING TO SNOW AS AN
UPPER LEVEL TROF MOVES IN TUESDAY. LINGERING SNOW SHOWERS INTO
WEDNESDAY. CLOSE TO NORMAL TEMPS FOR TUESDAY.
PREVIOUS DISCUSSION...
A WEAK SHORT WAVE TROUGH WILL MOVE ACROSS THE CWA FRIDAY NIGHT. BY
SATURDAY MORNING, A RIDGE OF HIGH PRESSURE WILL BUILD IN,
BRINGING MAINLY QUIET WEATHER TO THE FORECAST AREA. ANOTHER,
STRONGER, SW WILL APPROACH THE CWA LATE SUNDAY AFTERNOON. THIS
WILL BRING ANOTHER ROUND OF PRECIPITATION FROM SUNDAY EVENING
THROUGH TUESDAY. CURRENTLY THINKING THIS SHOULD AGAIN BE MAINLY A
RAIN EVENT. SOME COLD AIR WILL MOVE INTO THE AREA BY TUESDAY
MORNING WHICH SHOULD ALLOW WHATEVER SHOWER ARES TILL AROUND TO
CHANGE OVER TO SNOW.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
UPR LVL TROF AND ASSCD 2NDRY SFC TROF CRNTLY WORKING ACRS THE
FCST AREA. AREAS OF MVFR CIGS/VSBY`S WITH -SHRA/-SHSN...MOST
WDSPRD ACRS CNTRL NY...WILL PERSIST INTO THE EVNG HRS. DIFFS IN
THE MDLS W/RESPECT TO THE TIMING OF CLEARING TNGT...WITH CRUDE
EXTRAPOLATION SUPPORTING THE SLOWER RUC SCENARIO. HOWEVER...WE
THINK THE INDICATION OF MVFR CIGS PERSISTING WELL INTO THE OVRNGT
HRS AT PLACES LIKE ITH/BGM/AVP IS OVERDONE BY THE RUC. WE LEANED
TWDS A COMPROMISE WHICH SUGGESTS CLEARING OR PARTIAL CLEARING AT
MOST SPOTS IN THE 03-06Z TIME FRAME. AFTER THIS MSTR LIFTS
OUT..XPCT SCT-BKN HI CLDS ON THU. WINDS THIS AFTN AHEAD OF THE SFC
TROF SWLY 10-20 KTS...BECMG W TO NW 10-20 KTS BEHIND THE TROF.
WINDS SUBSIDING TNGT TO 5-10 KTS...THEN WRLY ON THU ARND 10 KTS.
OUTLOOK...
THURSDAY NIGHT...VFR.
FRIDAY...BRIEF PD OF MVFR PSBL ACRS CNTRL NY DUE TO CDFNT AND SCT
-SHRA.
FRI NGT/SATURDAY/SUNDAY...VFR.
MON...MVFR/IFR AS RAIN DVLPS ACRS THE AREA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN/RRM
SHORT TERM...HEDEN
LONG TERM...SLI/TAC