Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 01/23/12
AREA FORECAST DISCUSSION
NWS TAUNTON MA
932 PM EST SUN JAN 22 2012
.SYNOPSIS...
AN APPROACHING WARM FRONT MAY BRING SOME LIGHT FREEZING RAIN OR
DRIZZLE TO THE INTERIOR OVERNIGHT INTO MONDAY MORNING. A COLD
FRONT WILL BRING A PERIOD OF RAIN LATE MONDAY AND MONDAY NIGHT AS
IT SWEEPS ACROSS THE REGION. DRY AND SEASONABLE WEATHER PREVAILS
FOR MID WEEK AS HIGH PRESSURE BUILDS ACROSS THE EASTERN SEABOARD.
A WARM FRONT MAY BRING SOME LIGHT PRECIPITATION ON THURSDAY...THEN
A WEAK FRONT MAY AFFECT THE REGION THURSDAY NIGHT INTO EARLY
FRIDAY. LOW PRESSURE MAY WORK UP THE COAST SOMETIME NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
930 PM UPDATE...
LOW CLOUDS ARE FIRMLY ENTRENCHED OVER ALL OF AREA. TEMPERATURES
DROPPED OFF RAPIDLY ACROSS PARTS OF INTERIOR BUT NOW MOST
LOCATIONS HAVE EXPERIENCED THEIR OVERNIGHT LOWS. READINGS SHOULD
REMAIN STEADY OR RISE A FEW DEGREES...IN LINE WITH GFS LAMP WHICH
WAS USED FOR HOURLY TEMPERATURES.
ADVISORY REMAINS IN PLACE FOR INTERIOR. SEEING SOME LIGHT
PRECIPITATION RETURNS ON KOKX RADAR ACROSS LONG ISLAND AND NYC
AREA...WHICH IS WHERE HRRR KEEPS MOST OF ACTIVITY OVERNIGHT.
FORECAST SOUNDINGS IN OUR AREA ARE COLD ENOUGH TO SUPPORT FLURRIES
INITIALLY BUT MID LEVEL WARMING SHOULD YIELD FREEZING DRIZZLE/
LIGHT FREEZING RAIN AROUND DAYBREAK.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
MONDAY...
AREAS OF FZDZ OR LIGHT FZRA IS EXPECTED OVER THE INTERIOR IN THE
MORNING WITH TEMPS GRADUALLY WARMING ABOVE FREEZING FROM S TO N.
BUT IT MAY TAKE UNTIL AFTERNOON TO GET ABOVE FREEZING IN S NH. DO
NOT EXPECT MUCH PRECIP FOR MOST OF THE DAY AS AREA WILL BE IN MID
LEVEL DRY WEDGE...BUT HAVE POPS RAPIDLY INCREASING ACROSS W ZONES
BY LATE AFTERNOON AS DEEP MOISTURE PLUME AND LOW LEVEL JET
APPROACH FROM THE WEST. POPS INCREASE TO CATEGORICAL CT VALLEY W
BY DAYS END DECREASING TO CHC BOS-PVD CORRIDOR AND DRY
CAPE/ISLANDS. LATE AFTERNOON TEMPS WILL REACH MID 30S FAR N TO
MID/UPPER 40S S COAST...BUT HIGHEST TEMPS WILL LIKELY BE ACHIEVED
IN THE EVENING. PATCHY DENSE FOG MAY DEVELOP BY LATE AFTERNOON BUT
MORE LIKELY IN THE EVENING.
MON NIGHT...
AREA OF RAIN WHICH MAY BE BRIEFLY MODERATE TO HEAVY WILL MOVE W
TO E ACROSS SNE ASSOCD WITH LOW LEVEL JET AND DEEP MOISTURE PLUME
AHEAD OF THE COLD FRONT. ADVECTION OF HIGHER DEWPOINTS OVER THE
SNOW COVER WILL LIKELY RESULT IN AREAS OF DENSE FOG. GIVEN
PROGRESSIVE NATURE OF THIS SYSTEM QPF SHOULD BE LESS THAN AN INCH
WITH AMOUNTS GENERALLY 0.25" TO 0.75" AND THE RAIN SHOULD BE
OFFSHORE BY 12Z. TEMPS WILL RISE IN THE EVENING AND MAY REACH 50
DEGREES PORTIONS OF RI AND SE MA BEFORE SLOWLY COOLING TOWARD 12Z.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODEL DISCUSSION AND PREFERENCES...
NOTING GOOD AGREEMENT AMONGST THE MODEL SUITE THROUGH MID
WEEK...THEN START TO SEE TIMING DIFFERENCES DUE TO HANDLING OF
BUILDING RIDGE ACROSS THE EASTERN PACIFIC BEYOND MID-LATE WEEK. DID
NOTE SIGNIFICANT DIFFERENCES ON LAST COUPLE OF RUNS OF THE OP ECMWF
MODEL...BUT THE 12Z SOLUTION CAME IN RATHER CLOSE TO THE GFS
ESPECIALLY WITH POTENTIAL LOW PRES DEVELOPMENT SOMEWHERE ALONG THE
EASTERN SEABOARD NEXT WEEKEND. LEANED TOWARD THE GFS/UKMET SOLUTIONS
INTO THE WEEKEND...THEN THE GFS FOR NEXT WEEKEND...WHICH SHOWS GOOD
RUN TO RUN CONSISTENCY OVER THE LAST SEVERAL DAYS. THIS WAS CLOSE TO
HPC GUIDANCE...WHICH LOOKS GOOD.
TUESDAY...COLD FRONT CONTINUES TO PUSH OFFSHORE. MAY SEE LEFTOVER
RAIN SHOWERS EARLY TUESDAY ACROSS EASTERN AREAS BUT EXPECT TO CLEAR
QUICKLY AS DRIER AIR WORKS IN. MAY SEE GUSTS UP TO 20-25 KT DURING
THE AFTERNOON AS WINDS SHIFT TO W. COLDER AIR DOES NOT START MOVING
IN UNTIL LATER IN THE DAY...SO EXPECT HIGHS IN THE MID 40S TO LOWER
50S...RUNNING 10 TO 15 DEGREES ABOVE SEASONAL NORMALS. EXPECT H850
TEMPS TO DROP TUE NIGHT...SO LOWS WILL FALL BACK TO THE 20S.
WEDNESDAY...HIGH PRES WILL BUILD OUT OF THE MIDWEST DURING THE
DAY...BUT WILL STILL BE UNDER THE INFLUENCE OF NW FLOW AROUND STRONG
LOW PRES OVER THE MARITIMES. WILL BE A COLDER DAY THAN TUESDAY WITH
HIGHS IN THE MID-UPPER 30S ACROSS THE HIGHER TERRAIN TO THE MID 40S
ACROSS THE SOUTH. CLOUDS WILL START TO INCREASE WED NIGHT AS A WARM
FRONT STARTS TO APPROACH.
THURSDAY-FRIDAY...WEATHER WILL START OFF DRY ON THURSDAY...BUT
CLOUDS WILL CONTINUE TO INCREASE AS A WARM FRONT APPROACHES. EXPECT
CHANCE POPS MAINLY ACROSS N CT/RI/SE MA DURING THE AFTERNOON...THEN
WILL PUSH N THURSDAY NIGHT. LOW PRES AND A COLD FRONT WILL THEN
QUICKLY MOVE ACROSS LATE THU NIGHT INTO FRI MORNING. SKIES WILL
BECOME PARTLY CLOUDY DURING THE AFTERNOON.
FRIDAY NIGHT-SUNDAY...ECMWF CAME IN FAIRLY GOOD AGREEMENT WITH THE
GFS IN DEVELOPING SOUTHERN STREAM LOW PRES MOVING OFF THE ATLC
COAST. AS USUAL...BIG QUESTIONS AS TO TIMING AND TRACK THIS FAR
OUT...BUT THERE IS POTENTIAL FOR A WINTER STORM SOMETIME NEXT
WEEKEND. STILL WAY TOO FAR OUT TO CALL THIS...AND MANY MORE MODEL
RUNS TO SEE IF AND HOW THIS SYSTEM WILL DEVELOP AND ITS TRACK. HAVE
KEPT MENTION OF CHANCE POPS MOVING IN EARLY SAT THEN POSSIBLY MOVING
OUT SOMETIME EARLY SUN. CONFIDENCE IS LOW AT THIS TIME.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
TONIGHT...
MODERATE CONFIDENCE. MVFR CIGS HAVE MOVED INTO MOST AREAS EXCEPT
CENTRAL AND NORTHERN CONNECTICUT VALLEY AT 00Z. EXPECT THE LOW
CLOUDS TO MOVE THERE AS WELL. MAY SEE A FEW BREAKS IN LOW CLOUDS
BRIEFLY THIS EVENING...BUT EXPECT MAINLY MVFR CIGS THROUGH THE
NIGHT. AREAS OF FREEZING DRIZZLE MAY DEVELOP AROUND MIDNIGHT IN THE
CT VALLEY AND POSSIBLY SPREAD E TO LWM-BED-NW RI BY 12Z.
MONDAY...
MODERATE TO HIGH CONFIDENCE. MVFR CIGS WITH AREAS OF IFR IN THE
DISTANT INTERIOR. OVER THE CAPE/ISLANDS...MVFR CIGS COULD BECOME
VFR FOR A TIME. RISK OF FREEZING DRIZZLE NW OF LWM-BED-SFZ THRU
14Z...THEN GRADUALLY RETREATING N. AN AREA OF RAIN WILL BE MOVING
INTO W ZONES 18-00Z.
MONDAY NIGHT...
MODERATE TO HIGH CONFIDENCE. AS HIGHER DEWPOINT AIR ADVECTS NWD
OVER SNOW PACK...EXPECT CIGS/VSBYS TO LOWER TO IFR/LIFR WITH AREAS
OF DENSE FOG. A PERIOD OF RAIN WILL MOVE WEST TO EAST ACROSS THE
REGION. IN ADDITION...LOW LEVEL JET WILL LIKELY RESULT IN LLWS.
KBOS TERMINAL...
MODERATE CONFIDENCE. MVFR CIGS 2-3 KFT WILL LIKELY PERSIST THROUGH
THE PERIOD ALTHOUGH IT IS POSSIBLE CLOUDS COULD BECOME SCT THROUGH
TONIGHT. IFR CIGS SHOULD HOLD OFF UNTIL MON EVENING. BULK OF
RAINFALL WILL HOLD OFF TIL MON EVENING.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUESDAY...MODERATE TO HIGH CONFIDENCE. MAY SEE PATCHY MVFR
CIGS/VSBYS ACROSS E MA/RI EARLY...BUT SHOULD IMPROVE TO VFR BY MID
MORNING. EXPECT VFR THROUGH TUE NIGHT.
WEDNESDAY...HIGH CONFIDENCE FOR VFR CONDITIONS. WEST WINDS GUSTING
TO AROUND 25 KT MAINLY ALONG THE COAST AND ACROSS THE HIGHER TERRAIN.
THURSDAY...LOW TO MODERATE CONFIDENCE. VFR TO START...THEN LOWERING
TO MVFR-IFR CIGS/VSBYS IN DEVELOPING RAIN/SNOW...MAINLY SNOW THU
NIGHT. MAY ALSO SEE AREAS OF FOG.
FRIDAY...LOW TO MODERATE CONFIDENCE...MAINLY FOR TIMING. MVFR
CIGS/VSBYS TO START...THEN IMPROVING TO VFR FROM W-E DURING THE
MORNING. WEST WINDS GUSTING TO 25-30 KT...HIGHEST ACROSS THE HIGHER
TERRAIN AND ALONG THE E COAST.
&&
.MARINE...
WINDS VEERING TO SE TONIGHT WITH SPEEDS BELOW SCA AND MAINLY SE
WIND 15-20 KT MONDAY. SEAS OVER THE OUTER WATERS WILL BE SUBSIDING
BELOW 5 FT TONIGHT. AS THE LOW LEVEL JET MOVES ACROSS THE WATERS
MON NIGHT A PERIOD OF SOUTHERLY WIND GUSTS TO 25 KT LIKELY WITH
BUILDING SEAS. BUT STRONG LOW LEVEL INVERSION SHOULD KEEP WINDS
WELL BELOW GALE.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUESDAY...EXPECT SW WINDS TO SHIFT TO W DURING THE DAY. GUSTS TO 25
KT MAINLY OVER THE OPEN WATERS. SEAS BUILD UP TO 5-6 FT ON THE
SOUTHERN WATERS.
WEDNESDAY-THURSDAY...W WINDS GUSTING UP TO 25 KT THROUGH WED
NIGHT...THEN WILL DIMINISH. WINDS BACK TO S THU NIGHT. SEAS 5-6 FT
OVER THE OPEN WATERS THROUGH WED NIGHT...THEN SUBSIDING.
FRIDAY...W WINDS GUSTING TO 30 KT...BACKING TO SW FRI NIGHT. SEAS
BUILDING TO 5-7 FT ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY UNTIL 11 AM EST MONDAY FOR CTZ002>004.
MA...FREEZING RAIN ADVISORY UNTIL 11 AM EST MONDAY FOR MAZ002>006-
008>012-026.
NH...FREEZING RAIN ADVISORY UNTIL 11 AM EST MONDAY FOR NHZ011-012-
015.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR ANZ254-255.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR ANZ256.
&&
$$
SYNOPSIS...KJC/EVT
NEAR TERM...JWD
SHORT TERM...KJC
LONG TERM...EVT
AVIATION...KJC/EVT
MARINE...KJC/EVT
AREA FORECAST DISCUSSION
NWS ALBANY NY
225 PM EST SAT JAN 21 2012
.SYNOPSIS...
A HIGH PRESSURE SYSTEM WILL BUILD INTO THE NORTHEAST TONIGHT AND
SUNDAY...BRINGING FAIR BUT COLD WEATHER. ON MONDAY...A POWERFUL
STORM WILL MOVE FROM THE UPPER GREAT LAKES REGION INTO WESTERN
QUEBEC...LIKELY BRINGING MIXED PRECIPITATION CHANGING TO RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM...SNOW HAS ENDED OR BECOME VERY LIGHT ACROSS THE
ADVISORY AREA (ULSTER...DUTCHESS...LITCHFIELD COUNTIES)...SO
CANCELLED THE ADVISORY JUST AFTER 200 PM. ONLY DECREASING CHANCE
POPS FORECAST FOR THE REST OF THE AFTERNOON. TEMPS HAVE ALSO BEEN
ADJUSTED DOWNWARD SINCE IT APPEARS THAT ANY CLEARING THAT OCCURS
WILL LIKELY ARRIVE TO LATE FOR THE SUN TO HAVE ANY IMPACT ON TEMPS.
****PREVIOUS DISCUSSION****
SNOW WINDING DOWN ACROSS MOST OF THE FORECAST AREA. BEST LIFT WITH
WARM ADVECTION AND SEEDER FEEDER PROCESS OVER SOUTHEAST. THIS WILL
GRADUALLY MOVE EAST NEXT FEW HOURS. SOME CLEARING NOTED OVER FINGER
LAKES/SOUTHERN ONTARIO AND THIS IS GRADUALLY MOVING IN.
LOW CLOUDS HANGING TOUGH OVER MOST OF FORECAST AREA. CLOUD TOP TEMPS
COLD ENOUGH FOR SNOW. WEAK WARM ADVECTION WILL CAUSE SOME LIGHT SNOW
INTO AFTERNOON BUT LITTLE ACCUMULATION EXPECTED OUTSIDE FAR
SOUTHEAST PART OF FORECAST AREA. TEMPS STILL NOT BUDGING MUCH.
CURRENT FORECAST MAX AT ALBANY 24F TODAY BUT THIS MAY BE OPTIMISTIC
IF CLOUDS DONT BREAK UP TILL LATE IN DAY.
LATEST UPDATE TO MODIFY CLOUDS/POPS/WX/WINDS BASED ON OBS/RADAR AND
12Z NAM.
PREVIOUS...
WEAK MIDLEVEL SYSTEM MOVING FROM WEST TO EAST. SNOW HAS ENDED OR
GREATLY DIMINISHED OVER NORTHWEST PART OF AREA. LATEST RUC ANALYSIS
SHOWS H850 WARM ADVECTION CONTINUING ACROSS THE AREA AND VAD WIND
PROFILE CONFIRMS THIS. SNOW SEEMS TO BE ENDING ONCE MID/HIGH LEVEL
CLOUDS MOVE AWAY AND SEEDER FEEDER MECHANISM DIMINISHES. CLOUD TOPS
COOLING OVER SOUTHEAST PART OF FORECAST AREA INDICATING ONE MORE
BAND OF MODERATE SNOW POSSIBLE THERE LATE THIS MORNING BEFORE HIGHER
CLOUDS MOVE OFF AND SNOW DIMINISHES.
RECENT UPDATE TO ADJUST POPS WHERE SNOW HAS DIMINISHED OR ENDED.
ALSO ADJUSTED MAX TEMPS DOWNWARD 2 DEGREES VALLEYS AND 3-5 DEGREES
MOUNTAINS AS OBS SHOW TEMPS NOT MOVING THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
WE BEGIN THIS SHORT TERM PORTION OF THE FORECAST ON A TRANQUIL
NOTE WITH A 1035MB SURFACE HIGH SLIDING ACROSS THE EASTERN GREAT
LAKES REGIONS AND NEW ENGLAND THROUGH THE DAY. FAIRLY DRY BELOW
500MB TO KEEP POPS AT ZERO AND SKIES PT-MOSUNNY. TEMPERATURES WILL
BE SEASONABLE FOR THIS TIME OF THE YEAR WITH MAINLY 20S FOR THE
TERRAIN AND LOWER 30S FOR THE VALLEY FLOOR.
MEANWHILE...A POWERFUL SHORT WAVE COINCIDING WITH 150KT UPPER
LEVEL JET WAS COMING ASHORE ACROSS CALIFORNIA. THIS SYSTEM IS
FORECAST BY THE NCEP MODEL SUITE TO IMPACT THE 4-CORNERS REGION
AND EJECT OUT ONTO THE CENTRAL-SOUTHERN PLAINS SUNDAY INTO MONDAY.
A POWERFUL SURFACE CYCLONE WILL DEVELOP OVER THE MID-LOWER
MISSISSIPPI RIVER VALLEY AND TRACK INTO THE CENTRAL GREAT LAKES
REGION THROUGH MONDAY. THE MAIN IMPACT FOR OUR REGION WILL BE AN
INCREASE IN CLOUD COVER AND A STRENGTHEN SOUTHERLY WIND.
HOWEVER...ISSUES ARISE OVERNIGHT SUNDAY INTO MONDAY MORNING FOR
THE REGION.
A CLOSER EXAMINATION OF BUFKIT AND HOURLY BUFR PROFILES FROM THE
MODEL SUITES THIS MORNING ALL SUGGEST A RAPID INCREASE IN LOWER
LEVEL MOISTURE FROM SOUTH TO NORTH. COMBINE THAT WITH THE WIND
MAGNITUDE INCREASE AND LOW LEVEL SHEAR FOR DRIZZLE FORMATION SINCE
ICE NUCLEI IS NOT EXPECTED IN THE COLUMN WITH THE HEIGHT OF THE
MOISTURE PROFILES STAYING BELOW THE -10C THROUGH AT LEAST 15Z
MONDAY. DUE TO SEASONABLE TEMPERATURES EXPECTED ON SUNDAY...AND
SOME PARTIAL CLEAR SKIES SUNDAY EVENING...OVERNIGHT SURFACE
TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE TEENS ACROSS THE
DACKS AND LOW-MID 20S ELSEWHERE. THIS SEEMS TO SUGGEST THAT ANY
DRIZZLE FORMATION WILL FREEZE ON CONTACT. TEMPERATURES ARE
EXPECTED TO CLIMB ABOVE FREEZING ALONG THE HEELS OF THE STRENGTHEN
SOUTHERLY FLOW BY NOON MONDAY WHERE WE WILL REMOVE THE MENTION OF
FROZEN DRIZZLE/RAIN.
MONDAY AFTERNOON...AN INCREASE IN LOW LEVEL WARM ADVECTION ALONG
WITH THE APPROACH OF THE FRONTAL BOUNDARY WILL KEEP POPS QUITE
HIGH FOR PERIODS OF RAIN/SHOWERS. THERE ARE SOME SUBTLE HINTS THAT
THUNDER COULD BE A POSSIBILITY SOUTH OF THE CAPITAL REGION WITH
SHOWALTER INDICES DROPPING BACK TO NEAR 1C AND SLIGHTLY FAVORABLE
MID LEVEL LAPSE RATES. WE WILL CONTINUE TO MONITOR AND NOT MENTION
IN THE FORECAST/GRIDS. HIGH TEMPERATURES COULD EXCEED 40F FOR THE
MAJORITY OF THE REGION.
THE FRONT AND ASSOCIATED MOISTURE TRACK QUICKLY TO OUR NORTHEAST
WITH A DECREASE IN POPS. HOWEVER...WITH A NEAR VERTICALLY STACKED
LOW OVER THE GREAT LAKES REGION AND COLD ADVECTION...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE. DELTA T/S ARE ONLY EXPECTED
TO REMAIN MARGINAL SO WE WILL KEEP POPS FOR PORTIONS OF THE DACKS
IN THE 30% THRESHOLDS FOR SNOW SHOWERS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE AFOREMENTIONED LAKE EFFECT ACTIVITY COULD STILL BE IMPACTING
PORTIONS OF THE DACKS WITH A WEST-SOUTHWEST BOUNDARY LAYER WINDS
AROUND THE PERIPHERY OF THE SLOWLY DEPARTING UPPER LOW.
OTHERWISE...BUILDING SURFACE PRESSURES ARE EXPECTED TUESDAY
THROUGH WEDNESDAY. A WEAK MID LEVEL IMPULSE APPROACHES LATE
WEDNESDAY AS THE MAIN IMPACT SHOULD BE FROM AN INCREASE IN HIGH-
MID LEVEL MOISTURE.
THURSDAY THRU FRIDAY...CONSIDERABLE UNCERTAINTY REMAINS AS THE GFS
REMAINS THE MOST PROGRESSIVE AND THE ECMWF A BIT MORE PRONOUNCED
WITH RESPECT TO APPALACHIANS STORM SYSTEM THAT COULD IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY. ENSEMBLES FROM THE GFS OFFER A
WIDE VARIETY OF SOLUTIONS WITH A FEW CLUSTERS EVEN STRONGER THAN
THE ECMWF AND FURTHER WEST. FOR NOW...A LOW CONFIDENCE FORECAST
FOR THE END OF THIS WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
SNOW WAS PRETTY MUCH ENDED AT KALB. KGFL WAS EXPERIENCING A PLUME
OF LIKELY WIND CONVERGENCE -SN/-SHSN EMANATING FROM THE TUG HILL
AREA. HAVE GONE WITH JUST A ONE-HOUR TAF ONSET TEMPO GROUP THERE
FOR IFR VSBY IN -SN AS THIS FEATURE WILL WEAKEN AS A HIGH PRESSURE
RIDGE BUILDS IN THROUGH THIS EVENING. OTRW...BOTH KGFL AND KALB
WILL HANG ONTO MVFR CLOUDS FOR AWHILE. AT KPOU...TIMING OF ACTIVITY
PULLOUT IS SOMEWHAT UNCERTAIN. HAVE IT ENDING AT 22Z. LIKE KGFL...
HAVE GIVEN THEM A ONE-HOUR ONSET TEMPO OF IFR VSBY IN -SN TO REFLECT
MOST RECENT SCENARIO...BUT UNLIKE KGFL...A DIFFERENT MECHANISM.
SUBSIDENCE HIGH PRESSURE ENHANCES OVER THE AIRPORTS THIS EVENING.
DEPARTING LOW IS NOT EXPECTED TO STRENGTHEN AS THIS OCCURS...SO
GRADUAL CLEARING OF ALL THE LOW AND MID LEVEL CLOUDS IS EXPECTED
THROUGH THE NIGHT WHILE WINDS DIMINISH. HIGH CLOUDINESS IS EXPECTED
TO MOVE IN WELL AHEAD OF THE NEXT SYSTEM...BUT SHOULD REMAIN THIN.
GIVEN THIS SCENARIO...WINDS WILL NOT BE OF GREAT CONCERN...WITH
NEARLY CALM SURFACE CONDITIONS EXPECTED ON SUNDAY. SOME LOW- TO
MID-LEVEL WIND ENHANCEMENT WILL OCCUR...BUT THIS WILL FALL WELL
SHORT OF PRODUCING ANY WIND SHEAR ISSUES. TEMPERATURES OF GROUND
AND DRY AIR REMAINING QUITE COLD OVERNIGHT WILL KEEP FOG CLEAN OUT
OF THE PICTURE.
OUTLOOK...
SUN PM...VFR...NO SIG WX.
MON AM...MAINLY VFR...CHC -FZDZ.
MON AFTN-EVENING...MVFR/IFR RA LIKELY
MON NGT-WED...VFR...NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
NEXT FRIDAY. ANY PRECIPITATION WHICH FALLS THROUGH THIS WEEKEND
WILL BE SNOW. MONDAY MAY BRING SOME LIGHT MIXED PRECIPITATION
EARLY AND 0.25" TO 0.50" OF RAIN DURING THE AFTERNOON.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE WEEKEND AS COLD AIR WILL BE IN PLACE ACROSS THE
REGION. TEMPS WILL BEGIN RISING LATE SUNDAY AND MONDAY...ONLY
COOLING TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ063>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/SNYDER/SND
NEAR TERM...GJM/SND
SHORT TERM...BGM
LONG TERM...BGM
AVIATION...ELH
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
1252 PM EST SAT JAN 21 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL TRACK OFF THE NEW JERSEY COAST TODAY AND
BRING SNOW TO THE AREA. A HIGH PRESSURE SYSTEM WILL BUILD INTO THE
NORTHEAST TONIGHT AND SUNDAY BRINGING FAIR WEATHER. ON MONDAY...A
POWERFUL STORM MOVES FROM THE UPPER GREAT LAKES INTO WESTERN
QUEBEC...LIKELY BRINGING MIXED PRECIPITATION CHANGING TO RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
SNOW WINDING DOWN ACROSS MOST OF THE FORECAST AREA. BEST LIFT WITH
WARM ADVECTION AND SEEDER FEEDER PROCESS OVER SOUTHEAST. THIS WILL
GRADUALLY MOVE EAST NEXT FEW HOURS. SOME CLEARING NOTED OVER FINGER
LAKES/SOUTHERN ONTARIO AND THIS IS GRADUALLY MOVING IN.
LOW CLOUDS HANGING TOUGH OVER MOST OF FORECAST AREA. CLOUD TOP TEMPS
COLD ENOUGH FOR SNOW. WEAK WARM ADVECTION WILL CAUSE SOME LIGHT SNOW
INTO AFTERNOON BUT LITTLE ACCUMULATION EXPECTED OUTSIDE FAR
SOUTHEAST PART OF FORECAST AREA. TEMPS STILL NOT BUDGING MUCH.
CURRENT FORECAST MAX AT ALBANY 24F TODAY BUT THIS MAY BE OPTIMISTIC
IF CLOUDS DONT BREAK UP TILL LATE IN DAY.
LATEST UPDATE TO MODIFY CLOUDS/POPS/WX/WINDS BASED ON OBS/RADAR AND
12Z NAM.
PREVIOUS...
WEAK MIDLEVEL SYSTEM MOVING FROM WEST TO EAST. SNOW HAS ENDED OR
GREATLY DIMINISHED OVER NORTHWEST PART OF AREA. LATEST RUC ANALYSIS
SHOWS H850 WARM ADVECTION CONTINUING ACROSS THE AREA AND VAD WIND
PROFILE CONFIRMS THIS. SNOW SEEMS TO BE ENDING ONCE MID/HIGH LEVEL
CLOUDS MOVE AWAY AND SEEDER FEEDER MECHANISM DIMINISHES. CLOUD TOPS
COOLING OVER SOUTHEAST PART OF FORECAST AREA INDICATING ONE MORE
BAND OF MODERATE SNOW POSSIBLE THERE LATE THIS MORNING BEFORE HIGHER
CLOUDS MOVE OFF AND SNOW DIMINISHES.
RECENT UPDATE TO ADJUST POPS WHERE SNOW HAS DIMINISHED OR ENDED.
ALSO ADJUSTED MAX TEMPS DOWNWARD 2 DEGREES VALLEYS AND 3-5 DEGREES
MOUNTAINS AS OBS SHOW TEMPS NOT MOVING THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
WE BEGIN THIS SHORT TERM PORTION OF THE FORECAST ON A TRANQUIL
NOTE WITH A 1035MB SURFACE HIGH SLIDING ACROSS THE EASTERN GREAT
LAKES REGIONS AND NEW ENGLAND THROUGH THE DAY. FAIRLY DRY BELOW
500MB TO KEEP POPS AT ZERO AND SKIES PT-MOSUNNY. TEMPERATURES WILL
BE SEASONABLE FOR THIS TIME OF THE YEAR WITH MAINLY 20S FOR THE
TERRAIN AND LOWER 30S FOR THE VALLEY FLOOR.
MEANWHILE...A POWERFUL SHORT WAVE COINCIDING WITH 150KT UPPER
LEVEL JET WAS COMING ASHORE ACROSS CALIFORNIA. THIS SYSTEM IS
FORECAST BY THE NCEP MODEL SUITE TO IMPACT THE 4-CORNERS REGION
AND EJECT OUT ONTO THE CENTRAL-SOUTHERN PLAINS SUNDAY INTO MONDAY.
A POWERFUL SURFACE CYCLONE WILL DEVELOP OVER THE MID-LOWER
MISSISSIPPI RIVER VALLEY AND TRACK INTO THE CENTRAL GREAT LAKES
REGION THROUGH MONDAY. THE MAIN IMPACT FOR OUR REGION WILL BE AN
INCREASE IN CLOUD COVER AND A STRENGTHEN SOUTHERLY WIND.
HOWEVER...ISSUES ARISE OVERNIGHT SUNDAY INTO MONDAY MORNING FOR
THE REGION.
A CLOSER EXAMINATION OF BUFKIT AND HOURLY BUFR PROFILES FROM THE
MODEL SUITES THIS MORNING ALL SUGGEST A RAPID INCREASE IN LOWER
LEVEL MOISTURE FROM SOUTH TO NORTH. COMBINE THAT WITH THE WIND
MAGNITUDE INCREASE AND LOW LEVEL SHEAR FOR DRIZZLE FORMATION SINCE
ICE NUCLEI IS NOT EXPECTED IN THE COLUMN WITH THE HEIGHT OF THE
MOISTURE PROFILES STAYING BELOW THE -10C THROUGH AT LEAST 15Z
MONDAY. DUE TO SEASONABLE TEMPERATURES EXPECTED ON SUNDAY...AND
SOME PARTIAL CLEAR SKIES SUNDAY EVENING...OVERNIGHT SURFACE
TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE TEENS ACROSS THE
DACKS AND LOW-MID 20S ELSEWHERE. THIS SEEMS TO SUGGEST THAT ANY
DRIZZLE FORMATION WILL FREEZE ON CONTACT. TEMPERATURES ARE
EXPECTED TO CLIMB ABOVE FREEZING ALONG THE HEELS OF THE STRENGTHEN
SOUTHERLY FLOW BY NOON MONDAY WHERE WE WILL REMOVE THE MENTION OF
FROZEN DRIZZLE/RAIN.
MONDAY AFTERNOON...AN INCREASE IN LOW LEVEL WARM ADVECTION ALONG
WITH THE APPROACH OF THE FRONTAL BOUNDARY WILL KEEP POPS QUITE
HIGH FOR PERIODS OF RAIN/SHOWERS. THERE ARE SOME SUBTLE HINTS THAT
THUNDER COULD BE A POSSIBILITY SOUTH OF THE CAPITAL REGION WITH
SHOWALTER INDICES DROPPING BACK TO NEAR 1C AND SLIGHTLY FAVORABLE
MID LEVEL LAPSE RATES. WE WILL CONTINUE TO MONITOR AND NOT MENTION
IN THE FORECAST/GRIDS. HIGH TEMPERATURES COULD EXCEED 40F FOR THE
MAJORITY OF THE REGION.
THE FRONT AND ASSOCIATED MOISTURE TRACK QUICKLY TO OUR NORTHEAST
WITH A DECREASE IN POPS. HOWEVER...WITH A NEAR VERTICALLY STACKED
LOW OVER THE GREAT LAKES REGION AND COLD ADVECTION...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE. DELTA T/S ARE ONLY EXPECTED
TO REMAIN MARGINAL SO WE WILL KEEP POPS FOR PORTIONS OF THE DACKS
IN THE 30% THRESHOLDS FOR SNOW SHOWERS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE AFOREMENTIONED LAKE EFFECT ACTIVITY COULD STILL BE IMPACTING
PORTIONS OF THE DACKS WITH A WEST-SOUTHWEST BOUNDARY LAYER WINDS
AROUND THE PERIPHERY OF THE SLOWLY DEPARTING UPPER LOW.
OTHERWISE...BUILDING SURFACE PRESSURES ARE EXPECTED TUESDAY
THROUGH WEDNESDAY. A WEAK MID LEVEL IMPULSE APPROACHES LATE
WEDNESDAY AS THE MAIN IMPACT SHOULD BE FROM AN INCREASE IN HIGH-
MID LEVEL MOISTURE.
THURSDAY THRU FRIDAY...CONSIDERABLE UNCERTAINTY REMAINS AS THE GFS
REMAINS THE MOST PROGRESSIVE AND THE ECMWF A BIT MORE PRONOUNCED
WITH RESPECT TO APPALACHIANS STORM SYSTEM THAT COULD IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY. ENSEMBLES FROM THE GFS OFFER A
WIDE VARIETY OF SOLUTIONS WITH A FEW CLUSTERS EVEN STRONGER THAN
THE ECMWF AND FURTHER WEST. FOR NOW...A LOW CONFIDENCE FORECAST
FOR THE END OF THIS WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
SNOW WAS PRETTY MUCH ENDED AT KALB. KGFL WAS EXPERIENCING A PLUME
OF LIKELY WIND CONVERGENCE -SN/-SHSN EMANATING FROM THE TUG HILL
AREA. HAVE GONE WITH JUST A ONE-HOUR TAF ONSET TEMPO GROUP THERE
FOR IFR VSBY IN -SN AS THIS FEATURE WILL WEAKEN AS A HIGH PRESSURE
RIDGE BUILDS IN THROUGH THIS EVENING. OTRW...BOTH KGFL AND KALB
WILL HANG ONTO MVFR CLOUDS FOR AWHILE. AT KPOU...TIMING OF ACTIVITY
PULLOUT IS SOMEWHAT UNCERTAIN. HAVE IT ENDING AT 22Z. LIKE KGFL...
HAVE GIVEN THEM A ONE-HOUR ONSET TEMPO OF IFR VSBY IN -SN TO REFLECT
MOST RECENT SCENARIO...BUT UNLIKE KGFL...A DIFFERENT MECHANISM.
SUBSIDENCE HIGH PRESSURE ENHANCES OVER THE AIRPORTS THIS EVENING.
DEPARTING LOW IS NOT EXPECTED TO STRENGTHEN AS THIS OCCURS...SO
GRADUAL CLEARING OF ALL THE LOW AND MID LEVEL CLOUDS IS EXPECTED
THROUGH THE NIGHT WHILE WINDS DIMINISH. HIGH CLOUDINESS IS EXPECTED
TO MOVE IN WELL AHEAD OF THE NEXT SYSTEM...BUT SHOULD REMAIN THIN.
GIVEN THIS SCENARIO...WINDS WILL NOT BE OF GREAT CONCERN...WITH
NEARLY CALM SURFACE CONDITIONS EXPECTED ON SUNDAY. SOME LOW- TO
MID-LEVEL WIND ENHANCEMENT WILL OCCUR...BUT THIS WILL FALL WELL
SHORT OF PRODUCING ANY WIND SHEAR ISSUES. TEMPERATURES OF GROUND
AND DRY AIR REMAINING QUITE COLD OVERNIGHT WILL KEEP FOG CLEAN OUT
OF THE PICTURE.
OUTLOOK...
SUN PM...VFR...NO SIG WX.
MON AM...MAINLY VFR...CHC -FZDZ.
MON AFTN-EVENING...MVFR/IFR RA LIKELY
MON NGT-WED...VFR...NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
NEXT FRIDAY. ANY PRECIPITATION WHICH FALLS THROUGH THIS WEEKEND
WILL BE SNOW. MONDAY MAY BRING SOME LIGHT MIXED PRECIPITATION
EARLY AND 0.25" TO 0.50" OF RAIN DURING THE AFTERNOON.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE WEEKEND AS COLD AIR WILL BE IN PLACE ACROSS THE
REGION. TEMPS WILL BEGIN RISING LATE SUNDAY AND MONDAY...ONLY
COOLING TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ063>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER/SND
NEAR TERM...SND
SHORT TERM...BGM
LONG TERM...BGM
AVIATION...ELH
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
1213 PM EST SAT JAN 21 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL TRACK OFF THE NEW JERSEY COAST TODAY AND
BRING SNOW TO THE AREA. A HIGH PRESSURE SYSTEM WILL BUILD INTO THE
NORTHEAST TONIGHT AND SUNDAY BRINGING FAIR WEATHER. ON MONDAY...A
POWERFUL STORM MOVES FROM THE UPPER GREAT LAKES INTO WESTERN
QUEBEC...LIKELY BRINGING MIXED PRECIPITATION CHANGING TO RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
SNOW WINDING DOWN ACROSS MOST OF THE FORECAST AREA. BEST LIFT WITH
WARM ADVECTION AND SEEDER FEEDER PROCESS OVER SOUTHEAST. THIS WILL
GRADUALLY MOVE EAST NEXT FEW HOURS. SOME CLEARING NOTED OVER FINGER
LAKES/SOUTHERN ONTARIO AND THIS IS GRADUALLY MOVING IN.
LOW CLOUDS HANGING TOUGH OVER MOST OF FORECAST AREA. CLOUD TOP TEMPS
COLD ENOUGH FOR SNOW. WEAK WARM ADVECTION WILL CAUSE SOME LIGHT SNOW
INTO AFTERNOON BUT LITTLE ACCUMULATION EXPECTED OUTSIDE FAR
SOUTHEAST PART OF FORECAST AREA. TEMPS STILL NOT BUDGING MUCH.
CURRENT FORECAST MAX AT ALBANY 24F TODAY BUT THIS MAY BE OPTIMISTIC
IF CLOUDS DONT BREAK UP TILL LATE IN DAY.
LATEST UPDATE TO MODIFY CLOUDS/POPS/WX/WINDS BASED ON OBS/RADAR AND
12Z NAM.
PREVIOUS...
WEAK MIDLEVEL SYSTEM MOVING FROM WEST TO EAST. SNOW HAS ENDED OR
GREATLY DIMINISHED OVER NORTHWEST PART OF AREA. LATEST RUC ANALYSIS
SHOWS H850 WARM ADVECTION CONTINUING ACROSS THE AREA AND VAD WIND
PROFILE CONFIRMS THIS. SNOW SEEMS TO BE ENDING ONCE MID/HIGH LEVEL
CLOUDS MOVE AWAY AND SEEDER FEEDER MECHANISM DIMINISHES. CLOUD TOPS
COOLING OVER SOUTHEAST PART OF FORECAST AREA INDICATING ONE MORE
BAND OF MODERATE SNOW POSSIBLE THERE LATE THIS MORNING BEFORE HIGHER
CLOUDS MOVE OFF AND SNOW DIMINISHES.
RECENT UPDATE TO ADJUST POPS WHERE SNOW HAS DIMINISHED OR ENDED.
ALSO ADJUSTED MAX TEMPS DOWNWARD 2 DEGREES VALLEYS AND 3-5 DEGREES
MOUNTAINS AS OBS SHOW TEMPS NOT MOVING THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
WE BEGIN THIS SHORT TERM PORTION OF THE FORECAST ON A TRANQUIL
NOTE WITH A 1035MB SURFACE HIGH SLIDING ACROSS THE EASTERN GREAT
LAKES REGIONS AND NEW ENGLAND THROUGH THE DAY. FAIRLY DRY BELOW
500MB TO KEEP POPS AT ZERO AND SKIES PT-MOSUNNY. TEMPERATURES WILL
BE SEASONABLE FOR THIS TIME OF THE YEAR WITH MAINLY 20S FOR THE
TERRAIN AND LOWER 30S FOR THE VALLEY FLOOR.
MEANWHILE...A POWERFUL SHORT WAVE COINCIDING WITH 150KT UPPER
LEVEL JET WAS COMING ASHORE ACROSS CALIFORNIA. THIS SYSTEM IS
FORECAST BY THE NCEP MODEL SUITE TO IMPACT THE 4-CORNERS REGION
AND EJECT OUT ONTO THE CENTRAL-SOUTHERN PLAINS SUNDAY INTO MONDAY.
A POWERFUL SURFACE CYCLONE WILL DEVELOP OVER THE MID-LOWER
MISSISSIPPI RIVER VALLEY AND TRACK INTO THE CENTRAL GREAT LAKES
REGION THROUGH MONDAY. THE MAIN IMPACT FOR OUR REGION WILL BE AN
INCREASE IN CLOUD COVER AND A STRENGTHEN SOUTHERLY WIND.
HOWEVER...ISSUES ARISE OVERNIGHT SUNDAY INTO MONDAY MORNING FOR
THE REGION.
A CLOSER EXAMINATION OF BUFKIT AND HOURLY BUFR PROFILES FROM THE
MODEL SUITES THIS MORNING ALL SUGGEST A RAPID INCREASE IN LOWER
LEVEL MOISTURE FROM SOUTH TO NORTH. COMBINE THAT WITH THE WIND
MAGNITUDE INCREASE AND LOW LEVEL SHEAR FOR DRIZZLE FORMATION SINCE
ICE NUCLEI IS NOT EXPECTED IN THE COLUMN WITH THE HEIGHT OF THE
MOISTURE PROFILES STAYING BELOW THE -10C THROUGH AT LEAST 15Z
MONDAY. DUE TO SEASONABLE TEMPERATURES EXPECTED ON SUNDAY...AND
SOME PARTIAL CLEAR SKIES SUNDAY EVENING...OVERNIGHT SURFACE
TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE TEENS ACROSS THE
DACKS AND LOW-MID 20S ELSEWHERE. THIS SEEMS TO SUGGEST THAT ANY
DRIZZLE FORMATION WILL FREEZE ON CONTACT. TEMPERATURES ARE
EXPECTED TO CLIMB ABOVE FREEZING ALONG THE HEELS OF THE STRENGTHEN
SOUTHERLY FLOW BY NOON MONDAY WHERE WE WILL REMOVE THE MENTION OF
FROZEN DRIZZLE/RAIN.
MONDAY AFTERNOON...AN INCREASE IN LOW LEVEL WARM ADVECTION ALONG
WITH THE APPROACH OF THE FRONTAL BOUNDARY WILL KEEP POPS QUITE
HIGH FOR PERIODS OF RAIN/SHOWERS. THERE ARE SOME SUBTLE HINTS THAT
THUNDER COULD BE A POSSIBILITY SOUTH OF THE CAPITAL REGION WITH
SHOWALTER INDICES DROPPING BACK TO NEAR 1C AND SLIGHTLY FAVORABLE
MID LEVEL LAPSE RATES. WE WILL CONTINUE TO MONITOR AND NOT MENTION
IN THE FORECAST/GRIDS. HIGH TEMPERATURES COULD EXCEED 40F FOR THE
MAJORITY OF THE REGION.
THE FRONT AND ASSOCIATED MOISTURE TRACK QUICKLY TO OUR NORTHEAST
WITH A DECREASE IN POPS. HOWEVER...WITH A NEAR VERTICALLY STACKED
LOW OVER THE GREAT LAKES REGION AND COLD ADVECTION...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE. DELTA T/S ARE ONLY EXPECTED
TO REMAIN MARGINAL SO WE WILL KEEP POPS FOR PORTIONS OF THE DACKS
IN THE 30% THRESHOLDS FOR SNOW SHOWERS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE AFOREMENTIONED LAKE EFFECT ACTIVITY COULD STILL BE IMPACTING
PORTIONS OF THE DACKS WITH A WEST-SOUTHWEST BOUNDARY LAYER WINDS
AROUND THE PERIPHERY OF THE SLOWLY DEPARTING UPPER LOW.
OTHERWISE...BUILDING SURFACE PRESSURES ARE EXPECTED TUESDAY
THROUGH WEDNESDAY. A WEAK MID LEVEL IMPULSE APPROACHES LATE
WEDNESDAY AS THE MAIN IMPACT SHOULD BE FROM AN INCREASE IN HIGH-
MID LEVEL MOISTURE.
THURSDAY THRU FRIDAY...CONSIDERABLE UNCERTAINTY REMAINS AS THE GFS
REMAINS THE MOST PROGRESSIVE AND THE ECMWF A BIT MORE PRONOUNCED
WITH RESPECT TO APPALACHIANS STORM SYSTEM THAT COULD IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY. ENSEMBLES FROM THE GFS OFFER A
WIDE VARIETY OF SOLUTIONS WITH A FEW CLUSTERS EVEN STRONGER THAN
THE ECMWF AND FURTHER WEST. FOR NOW...A LOW CONFIDENCE FORECAST
FOR THE END OF THIS WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
MVFR CIGS/VSBY IN -SN EXIST OVER MOST OF FCA. OVER NEXT FEW HRS MOST
AREAS FM ADIRONDACKS SOUTH WILL LOWER TO MVFR/IFR CIGS AND VSBY IN
-SN. IFR CONDS WILL BE MORE WIDESPREAD SOUTH. CONDS WILL IMPV DURING
THE AFTN BCMG MVFR FM NW TO SE...AND VFR BY EVENING. WINDS WILL BE
NORTH-NORTHEAST AROUND 5-10 KT TODAY.
OUTLOOK...
SAT NIGHT-SUN...VFR. NO SIG WX.
SUN NIGHT-MON MRNG...BCMG MVFR/IFR LATE. CHC -RA/-SN/-PL/-FZRA.
MON AFTN...MVFR/IFR. RA LIKELY.
MON NIGHT-TUE...VFR. SLIGHT CHC -SHRASN AND MVFR.
TUE NIGHT-WED...VFR. NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
NEXT FRIDAY. ANY PRECIPITATION WHICH FALLS THROUGH THIS WEEKEND
WILL BE SNOW. MONDAY MAY BRING SOME LIGHT MIXED PRECIPITATION
EARLY AND 0.25" TO 0.50" OF RAIN DURING THE AFTERNOON.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE WEEKEND AS COLD AIR WILL BE IN PLACE ACROSS THE
REGION. TEMPS WILL BEGIN RISING LATE SUNDAY AND MONDAY...ONLY
COOLING TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ063>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER/SND
NEAR TERM...SND
SHORT TERM...BGM
LONG TERM...BGM
AVIATION...SNYDER
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
1000 AM EST SAT JAN 21 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL TRACK OFF THE NEW JERSEY COAST TODAY AND
BRING SNOW TO THE AREA. A HIGH PRESSURE SYSTEM WILL BUILD INTO THE
NORTHEAST TONIGHT AND SUNDAY BRINGING FAIR WEATHER. ON MONDAY...A
POWERFUL STORM MOVES FROM THE UPPER GREAT LAKES INTO WESTERN
QUEBEC...LIKELY BRINGING MIXED PRECIPITATION CHANGING TO RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK MIDLEVEL SYSTEM MOVING FROM WEST TO EAST. SNOW HAS ENDED OR
GREATLY DIMINISHED OVER NORTHWEST PART OF AREA. LATEST RUC ANALYSIS
SHOWS H850 WARM ADVECTION CONTINUING ACROSS THE AREA AND VAD WIND
PROFILE CONFIRMS THIS. SNOW SEEMS TO BE ENDING ONCE MID/HIGH LEVEL
CLOUDS MOVE AWAY AND SEEDER FEEDER MECHANISM DIMINISHES. CLOUD TOPS
COOLING OVER SOUTHEAST PART OF FORECAST AREA INDICATING ONE MORE
BAND OF MODERATE SNOW POSSIBLE THERE LATE THIS MORNING BEFORE HIGHER
CLOUDS MOVE OFF AND SNOW DIMINISHES.
RECENT UPDATE TO ADJUST POPS WHERE SNOW HAS DIMINISHED OR ENDED.
ALSO ADJUSTED MAX TEMPS DOWNWARD 2 DEGREES VALLEYS AND 3-5 DEGREES
MOUNTAINS AS OBS SHOW TEMPS NOT MOVING THIS MORNING.
PREVIOUS...
CURRENTLY -SN HAS OVER SPREAD MOST OF NY FCA EXCPT N ADIRONDACKS
AND W NEW ENG...WHERE SNOW WILL BEGIN SHORTLY. OTHER THAN SOME
MINOR ADJUSTMENTS TO POPS/WX FCST REMAINS ON TRACK.
SURFACE WAVE MOVES FROM TN VLY TO NJ COAST TODAY. ISENTROPIC LIFT
IS MAIN MECHANISM PRODUCING UVM FOR SNOW TODAY. ALTHOUGH 500HPA
TROF AND ITS VORT MAX PASSING ACROSS US/CAN BORDER RGN SUPPORT
SOME UVM IN N PTNS OF FCA. OVERALL SNOW WILL BE GENERALLY LIGHT
ON ORDER OF 1-3 INCHES...EXCEPT IN SOUTHERN MOST AREAS WHERE
MODERATE AMOUNTS ARE EXPECTED (3-6IN) CLOSEST TO THE BEST
ISENTROPIC LIFT AND UVM.
MODELS (GEM/NAM/GFS/ECMWF) IN GOOD AGREEMENT FOR THIS PERIOD. QPF
A BLEND OF CURRENT FCST...HPC AND ALL 00UTC MODELS. GIVEN CONTRAST
ACROSS THERMAL RIBBON USED SNOW/LIQ RATIO OF 13. AS OF 230AM -SN
HAS REACHED A RME-BGM LINE. THIS WILL CONTINUE TO ADVANCE REACHING
HUD VLY BY 5-6AM.
SNOW WILL PERSIST INTO THE EARLY AFTN THEN END RAPIDLY FM NW TO SE
AS 500HPA TROF AND SFC LOW MOVES OFFSHORE CUTTING OFF ISENTROPIC
LIFT. OVERNIGHT 500HPA RIDGE BUILDS INTO NE USA..AND SFC HIGH
BUILDS OVER NEW ENG AND NY IN RESPONSE TO DIF ACVA. SKIES WILL
CLEAR DURING THE LATE AFTN AND ERLY EVENING...WITH CLR CONDS AND
FRESH SNOW IN MOST AREAS. SHOULD ALLOW FOR GOOD RAD COOLING AND
TEMPS TO PLUNGE TO NR NORMAL.
WINDS SHOULD BE LIGHT NE DURING THIS PERIOD EXCEPT ARND 10KTS IN S
PTNS OF FCA.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
WE BEGIN THIS SHORT TERM PORTION OF THE FORECAST ON A TRANQUIL
NOTE WITH A 1035MB SURFACE HIGH SLIDING ACROSS THE EASTERN GREAT
LAKES REGIONS AND NEW ENGLAND THROUGH THE DAY. FAIRLY DRY BELOW
500MB TO KEEP POPS AT ZERO AND SKIES PT-MOSUNNY. TEMPERATURES WILL
BE SEASONABLE FOR THIS TIME OF THE YEAR WITH MAINLY 20S FOR THE
TERRAIN AND LOWER 30S FOR THE VALLEY FLOOR.
MEANWHILE...A POWERFUL SHORT WAVE COINCIDING WITH 150KT UPPER
LEVEL JET WAS COMING ASHORE ACROSS CALIFORNIA. THIS SYSTEM IS
FORECAST BY THE NCEP MODEL SUITE TO IMPACT THE 4-CORNERS REGION
AND EJECT OUT ONTO THE CENTRAL-SOUTHERN PLAINS SUNDAY INTO MONDAY.
A POWERFUL SURFACE CYCLONE WILL DEVELOP OVER THE MID-LOWER
MISSISSIPPI RIVER VALLEY AND TRACK INTO THE CENTRAL GREAT LAKES
REGION THROUGH MONDAY. THE MAIN IMPACT FOR OUR REGION WILL BE AN
INCREASE IN CLOUD COVER AND A STRENGTHEN SOUTHERLY WIND.
HOWEVER...ISSUES ARISE OVERNIGHT SUNDAY INTO MONDAY MORNING FOR
THE REGION.
A CLOSER EXAMINATION OF BUFKIT AND HOURLY BUFR PROFILES FROM THE
MODEL SUITES THIS MORNING ALL SUGGEST A RAPID INCREASE IN LOWER
LEVEL MOISTURE FROM SOUTH TO NORTH. COMBINE THAT WITH THE WIND
MAGNITUDE INCREASE AND LOW LEVEL SHEAR FOR DRIZZLE FORMATION SINCE
ICE NUCLEI IS NOT EXPECTED IN THE COLUMN WITH THE HEIGHT OF THE
MOISTURE PROFILES STAYING BELOW THE -10C THROUGH AT LEAST 15Z
MONDAY. DUE TO SEASONABLE TEMPERATURES EXPECTED ON SUNDAY...AND
SOME PARTIAL CLEAR SKIES SUNDAY EVENING...OVERNIGHT SURFACE
TEMPERATURES ARE EXPECTED TO DROP BACK INTO THE TEENS ACROSS THE
DACKS AND LOW-MID 20S ELSEWHERE. THIS SEEMS TO SUGGEST THAT ANY
DRIZZLE FORMATION WILL FREEZE ON CONTACT. TEMPERATURES ARE
EXPECTED TO CLIMB ABOVE FREEZING ALONG THE HEELS OF THE STRENGTHEN
SOUTHERLY FLOW BY NOON MONDAY WHERE WE WILL REMOVE THE MENTION OF
FROZEN DRIZZLE/RAIN.
MONDAY AFTERNOON...AN INCREASE IN LOW LEVEL WARM ADVECTION ALONG
WITH THE APPROACH OF THE FRONTAL BOUNDARY WILL KEEP POPS QUITE
HIGH FOR PERIODS OF RAIN/SHOWERS. THERE ARE SOME SUBTLE HINTS THAT
THUNDER COULD BE A POSSIBILITY SOUTH OF THE CAPITAL REGION WITH
SHOWALTER INDICES DROPPING BACK TO NEAR 1C AND SLIGHTLY FAVORABLE
MID LEVEL LAPSE RATES. WE WILL CONTINUE TO MONITOR AND NOT MENTION
IN THE FORECAST/GRIDS. HIGH TEMPERATURES COULD EXCEED 40F FOR THE
MAJORITY OF THE REGION.
THE FRONT AND ASSOCIATED MOISTURE TRACK QUICKLY TO OUR NORTHEAST
WITH A DECREASE IN POPS. HOWEVER...WITH A NEAR VERTICALLY STACKED
LOW OVER THE GREAT LAKES REGION AND COLD ADVECTION...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE. DELTA T/S ARE ONLY EXPECTED
TO REMAIN MARGINAL SO WE WILL KEEP POPS FOR PORTIONS OF THE DACKS
IN THE 30% THRESHOLDS FOR SNOW SHOWERS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE AFOREMENTIONED LAKE EFFECT ACTIVITY COULD STILL BE IMPACTING
PORTIONS OF THE DACKS WITH A WEST-SOUTHWEST BOUNDARY LAYER WINDS
AROUND THE PERIPHERY OF THE SLOWLY DEPARTING UPPER LOW.
OTHERWISE...BUILDING SURFACE PRESSURES ARE EXPECTED TUESDAY
THROUGH WEDNESDAY. A WEAK MID LEVEL IMPULSE APPROACHES LATE
WEDNESDAY AS THE MAIN IMPACT SHOULD BE FROM AN INCREASE IN HIGH-
MID LEVEL MOISTURE.
THURSDAY THRU FRIDAY...CONSIDERABLE UNCERTAINTY REMAINS AS THE GFS
REMAINS THE MOST PROGRESSIVE AND THE ECMWF A BIT MORE PRONOUNCED
WITH RESPECT TO APPALACHIANS STORM SYSTEM THAT COULD IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY. ENSEMBLES FROM THE GFS OFFER A
WIDE VARIETY OF SOLUTIONS WITH A FEW CLUSTERS EVEN STRONGER THAN
THE ECMWF AND FURTHER WEST. FOR NOW...A LOW CONFIDENCE FORECAST
FOR THE END OF THIS WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
MVFR CIGS/VSBY IN -SN EXIST OVER MOST OF FCA. OVER NEXT FEW HRS MOST
AREAS FM ADIRONDACKS SOUTH WILL LOWER TO MVFR/IFR CIGS AND VSBY IN
-SN. IFR CONDS WILL BE MORE WIDESPREAD SOUTH. CONDS WILL IMPV DURING
THE AFTN BCMG MVFR FM NW TO SE...AND VFR BY EVENING. WINDS WILL BE
NORTH-NORTHEAST AROUND 5-10 KT TODAY.
OUTLOOK...
SAT NIGHT-SUN...VFR. NO SIG WX.
SUN NIGHT-MON MRNG...BCMG MVFR/IFR LATE. CHC -RA/-SN/-PL/-FZRA.
MON AFTN...MVFR/IFR. RA LIKELY.
MON NIGHT-TUE...VFR. SLIGHT CHC -SHRASN AND MVFR.
TUE NIGHT-WED...VFR. NO SIG WX.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH
NEXT FRIDAY. ANY PRECIPITATION WHICH FALLS THROUGH THIS WEEKEND
WILL BE SNOW. MONDAY MAY BRING SOME LIGHT MIXED PRECIPITATION
EARLY AND 0.25" TO 0.50" OF RAIN DURING THE AFTERNOON.
ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE WEEKEND AS COLD AIR WILL BE IN PLACE ACROSS THE
REGION. TEMPS WILL BEGIN RISING LATE SUNDAY AND MONDAY...ONLY
COOLING TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ063>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER/SND
NEAR TERM...SNYDER/SND
SHORT TERM...BGM
LONG TERM...BGM
AVIATION...SNYDER
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
226 PM EST SAT JAN 21 2012
.SYNOPSIS...
A MOIST SOUTH FLOW WILL OCCUR AHEAD OF AN APPROACHING COLD FRONT.
THE FRONT WILL MOVE THROUGH THE FORECAST AREA TODAY AND BE STALLED
JUST SOUTH OF THE AREA SUNDAY. ANOTHER COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY. DRYING BEHIND THIS FRONT WILL DOMINATE
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH 800 PM...WIDESPREAD SHOWERS WERE OCCURRING AHEAD OF THE
COLD FRONT. THE SOUTH LOW-LEVEL FLOW PLUS A MOISTURE AND
INSTABILITY INCREASE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE
TROUGH WILL SUPPORT A FEW THUNDERSTORMS. THE EARLY AFTERNOON 88D
VAD WIND PROFILE INDICATED WINDS OF 45 KNOTS AT 3000 FEET. THE
LATEST RUC SHOWS THE SHEAR CONTINUING THROUGH THE REST OF THE
AFTERNOON. ENOUGH INSTABILITY MAY DEVELOP FOR SEVERE
THUNDERSTORMS. THE EARLY AFTERNOON ANALYSIS SHOWED LI/S RANGING
FROM 4 IN THE NORTH TO AROUND ZERO IN THE SOUTH APART OF THE
FORECAST AREA. UPSTREAM INSTABILITY SUPPORT THE NAM/S FORECAST OF
LI/S LOWERING TO AROUND -2 OVER THE SOUTH PART. SEVERE
THUNDERSTORMS APPEARS POSSIBLE IN THE SOUTH PART BASED ON THIS
INSTABILITY AND SHEAR.
AFTER 800 PM...
THE COLD FRONT WILL SINK SOUTH OF THE FORECAST AREA TONIGHT. THE GFS
AND NAM SHOW THE H85 JET LIFTING NORTHEAST OF THE FORECAST AREA
EARLY WITH MOISTURE BECOMING SHALLOW BEHIND THE MID-LEVEL SHORTWAVE
TROUGH. THE GFS AND NAM MOS INDICATE LOW POPS. FORECASTED CHANCE
POPS MAINLY ASSOCIATED WITH LINGERING CONVERGENCE NEAR THE FRONT.
USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
THE NAM AND GFS KEEP THE FRONT SOUTH OF THE AREA SUNDAY. THE MODELS
KEEP MOISTURE SHALLOW BUT SHOULD ISENTROPIC LIFT DEVELOPING. THIS
LIFT MAY SUPPORT LIGHT RAIN OR DRIZZLE. THE TEMPERATURE GUIDANCE
APPEARS TOO WARM BECAUSE OF THE WEDGE PATTERN. EXPECT THE WEDGE
PATTERN WILL REMAIN IN PLACE FOR MUCH OF SUNDAY NIGHT. THE MODELS
SHOW ANOTHER COLD FRONT MONDAY WITH INCREASED MOISTURE AND
CONVERGENCE. THE DEEPER MOISTURE APPEARS TO OCCUR DURING THE
MORNING. THE WARMER TEMPERATURE GUIDANCE APPEARED BETTER SUNDAY
NIGHT BECAUSE OF CLOUDINESS AND MIXING ASSOCIATED WITH THE
APPROACHING FRONT. THE TEMPERATURE GUIDANCE WAS CLOSE MONDAY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
DRY RIDGING BEHIND THE COLD FRONT SHOULD DOMINATE TUESDAY. THE GFS
AND ECMWF SUPPORT THIS DRY PATTERN. THE GFS AND ECMWF HAVE BEEN
INCONSISTENT WITH THE TIMING AND MOISTURE DURING THE REST OF THE
EXTENDED PERIOD. THE ECMWF HAS BEEN GENERALLY FASTER MOVING A WARM
ADVECTION AND HIGH MOISTURE BACK INTO THE FORECAST AREA. THE GFS
ENSEMBLE MEANS SUPPORT POPS LESS THAN 20 PERCENT WEDNESDAY...AND
CHANCE POPS DURING THE REST OF THE EXTENDED PERIOD.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
WIDESPREAD SHOWERS WILL CONTINUE AHEAD OF THE COLD FRONT. THERE
WILL ALSO BE A FEW THUNDERSTORMS...BUT THESE WERE NOT INCLUDED IN
THE FORECAST EXPLICITLY BECAUSE OF TIMING UNCERTAINTY. STRONG
WINDS ALOFT MAY MIX DOWN TO THE SURFACE WITH SOME OF THE STRONGER
SHOWERS. GENERALLY EXPECT MVFR CONDITIONS IN THE WARM SECTOR AHEAD
OF THE FRONT WITH LOWER CONDITIONS AT TIMES IN HEAVIER SHOWERS.
THE COLD FRONT WILL SINK SOUTH OF THE AREA IN THE 04Z TO 08Z TIME
FRAME. IFR CEILINGS WILL OCCUR IN THE MOIST NORTH FLOW BEHIND THE
FRONT.
EXTENDED AVIATION OUTLOOK...WIDESPREAD IFR CEILINGS WILL LIKELY
OCCUR DURING THE REST OF SUNDAY AND SUNDAY NIGHT ASSOCIATED WITH A
WARM FRONT. A COLD FRONT BE BE IN THE AREA MONDAY WITH CONTINUED
RESTRICTIONS FOR MUCH OF MONDAY. WIDESPREAD IFR CONDITION MAY
OCCUR WEDNESDAY NIGHT THROUGH THURSDAY ASSOCIATED WITH ANOTHER
FRONTAL SYSTEM.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
105 PM EST SAT JAN 21 2012
.SYNOPSIS...
A MOIST SOUTH FLOW WILL OCCUR AHEAD OF AN APPROACHING COLD FRONT.
THE FRONT WILL MOVE THROUGH THE FORECAST AREA TODAY AND BE STALLED
JUST SOUTH OF THE AREA SUNDAY. ANOTHER COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY. DRYING BEHIND THIS FRONT WILL DOMINATE
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH 800 PM...WIDESPREAD SHOWERS WERE OCCURRING AHEAD OF THE
COLD FRONT. THE SOUTH LOW-LEVEL FLOW PLUS A MOISTURE AND
INSTABILITY INCREASE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE
TROUGH WILL SUPPORT THUNDERSTORMS. THE EARLY AFTERNOON 88D VD
WIND PROFILE INDICATED WINDS OF 45 KNOTS AT 3000 FEET. THE LATEST
RUC SHOWS THE SHEAR CONTINUING THROUGH THE REST OF THE AFTERNOON.
ENOUGH INSTABILITY MAY DEVELOP FOR SEVERE THUNDERSTORMS. THE EARLY
AFTERNOON ANALYSIS SHOWED LI/S RANGING FROM 4 IN THE NORTH TO
AROUND ZERO IN THE SOUTH APART OF THE FORECAST AREA. UPSTREAM
INSTABILITY SUPPORT THE NAM/S FORECAST OF LI/S LOWERING TO AROUND
-2 OVER MUCH OF THE AREA DURING THE AFTERNOON. THE THREAT OF
SEVERE WEATHER APPEARS TO BE UNTIL AROUND 800 PM BASED ON THE
LATEST RUC MOISTURE CONVERGENCE PATTERN AND H85 JET.
AFTER 800 PM...
THE COLD FRONT WILL SINK SOUTH OF THE FORECAST AREA TONIGHT. THE GFS
AND NAM SHOW THE H85 JET LIFTING NORTHEAST OF THE FORECAST AREA
EARLY WITH MOISTURE BECOMING SHALLOW BEHIND THE MID-LEVEL SHORTWAVE
TROUGH. THE GFS AND NAM MOS INDICATE LOW POPS. FORECASTED CHANCE
POPS MAINLY ASSOCIATED WITH LINGERING CONVERGENCE NEAR THE FRONT.
USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
THE NAM AND GFS KEEP THE FRONT SOUTH OF THE AREA SUNDAY. THE MODELS
KEEP MOISTURE SHALLOW BUT SHOULD ISENTROPIC LIFT DEVELOPING. THIS
LIFT MAY SUPPORT LIGHT RAIN OR DRIZZLE. THE TEMPERATURE GUIDANCE
APPEARS TOO WARM BECAUSE OF THE WEDGE PATTERN. EXPECT THE WEDGE
PATTERN WILL REMAIN IN PLACE FOR MUCH OF SUNDAY NIGHT. THE MODELS
SHOW ANOTHER COLD FRONT MONDAY WITH INCREASED MOISTURE AND
CONVERGENCE. THE DEEPER MOISTURE APPEARS TO OCCUR DURING THE
MORNING. THE WARMER TEMPERATURE GUIDANCE APPEARED BETTER SUNDAY
NIGHT BECAUSE OF CLOUDINESS AND MIXING ASSOCIATED WITH THE
APPROACHING FRONT. THE TEMPERATURE GUIDANCE WAS CLOSE MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
DRY RIDGING BEHIND THE COLD FRONT SHOULD DOMINATE TUESDAY. THE GFS
AND ECMWF SUPPORT THIS DRY PATTERN. THE GFS AND ECMWF HAVE BEEN
INCONSISTENT WITH THE TIMING AND MOISTURE DURING THE REST OF THE
EXTENDED PERIOD. THE ECMWF HAS BEEN GENERALLY FASTER MOVING A WARM
ADVECTION AND HIGH MOISTURE BACK INTO THE FORECAST AREA. THE GFS
ENSEMBLE MEANS SUPPORT POPS LESS THAN 20 PERCENT WEDNESDAY...AND
CHANCE POPS DURING THE REST OF THE EXTENDED PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
WIDESPREAD SHOWERS WILL CONTINUE AHEAD OF THE COLD FRONT. THERE
WILL ALSO BE A FEW THUNDERSTORMS...BUT THESE WERE NOT INCLUDED IN
THE FORECAST EXPLICITLY BECAUSE OF TIMING UNCERTAINTY. STRONG
WINDS ALOFT MAY MIX DOWN TO THE SURFACE WITH SOME OF THE STRONGER
SHOWERS. GENERALLY EXPECT MVFR CONDITIONS IN THE WARM SECTOR AHEAD
OF THE FRONT WITH LOWER CONDITIONS AT TIMES IN HEAVIER SHOWERS.
THE COLD FRONT WILL SINK SOUTH OF THE AREA IN THE 04Z TO 08Z TIME
FRAME. IFR CEILINGS WILL OCCUR IN THE MOIST NORTH FLOW BEHIND THE
FRONT.
EXTENDED AVIATION OUTLOOK...WIDESPREAD IFR CEILINGS WILL LIKELY
OCCUR DURING THE REST OF SUNDAY AND SUNDAY NIGHT ASSOCIATED WITH A
WARM FRONT. A COLD FRONT BE BE IN THE AREA MONDAY WITH CONTINUED
RESTRICTIONS FOR MUCH OF MONDAY. WIDESPREAD IFR CONDITION MAY
OCCUR WEDNESDAY NIGHT THROUGH THURSDAY ASSOCIATED WITH ANOTHER
FRONTAL SYSTEM.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
938 AM EST SAT JAN 21 2012
.SYNOPSIS...
A MOIST SOUTH FLOW WILL OCCUR AHEAD OF AN APPROACHING COLD FRONT.
THE FRONT WILL MOVE THROUGH THE FORECAST AREA TODAY AND BE STALLED
JUST SOUTH OF THE AREA SUNDAY. ANOTHER COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY. DRYING BEHIND THIS FRONT WILL DOMINATE
TUESDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
MOISTURE WILL BE ON THE INCREASE IN THE SOUTH FLOW AHEAD OF THE
COLD FRONT. A MID-LEVEL SHORTWAVE TROUGH WILL ALSO BRING AN
INCREASE IN MOISTURE AND INSTABILITY. BELIEVE SHOWER COVERAGE WILL
INCREASE. THIS MORNING/S 88D VAD WIND PROFILE INDICATED WINDS OF
50 KNOTS AT 3000 FEET. THE LATEST RUC SHOWS THE SHEAR CONTINUING
DURING THE AFTERNOON. ENOUGH INSTABILITY MAY DEVELOP FOR SEVERE
THUNDERSTORMS. THE NAM SHOWS SURFACE-BASED LI/S LOWERING TO AROUND
-2. THE THREAT TIMING APPEARS TO BE MAINLY BETWEEN 200 PM AND 800
PM BASED ON THE LATEST RUC MOISTURE CONVERGENCE PATTERN AND H85
JET. THE SHEAR APPEARS UNI-DIRECTIONAL SUPPORTING MAINLY A
STRAIGHT-LINE WIND THREAT...EXCEPT THERE COULD POSSIBLY BE MORE
DIRECTIONAL SHEAR ALONG A LINGERING BOUNDARY IN THE NORTH PART OF
THE FORECAST AREA. REPORTS UPSTREAM ALSO SUPPORT A HAIL THREAT.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE COLD FRONT WILL MOVE THROUGH THE FORECAST AREA TONIGHT.
MOISTURE WILL BECOME SHALLOW BEHIND THE FRONT ON SUNDAY...BUT
ISENTROPIC LIFT MAY LEAD TO AREAS OF RAIN. MODELS CONTINUE TO
INDICATE THAT A LOW-LEVEL WEDGE PATTERN WILL SETUP SUNDAY AND
SUNDAY NIGHT. WITH SOME ISENTROPIC FLOW OVER THE WEDGE
POSSIBLE...CAN EXPECT TO HAVE SOME LIGHT RAIN AND DRIZZLE
THROUGHOUT THE DAY SUNDAY. THE TEMPERATURE GUIDANCE REMAINS TOO
WARM SUNDAY BECAUSE OF THE EXPECTED WEDGE PATTERN...AND THUS
CONTINUE TO UNDERCUT THE NUMBERS.
THE GFS SHOWED THE WEDGE FRONT TRYING TO LIFT NORTH OF THE
FORECAST AREA SUNDAY NIGHT. WEDGES SEEM TO STICK AROUND A LITTLE
LONGER THAN WHAT MODELS TYPICALLY FORECAST...SO WOULD EXPECT THE
WEDGE TO REMAIN SUNDAY NIGHT INTO MONDAY MORNING. EXPECTING A
CHANCE OF SHOWERS AND SOME POSSIBLE DRIZZLE SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ONLY MINOR CHANGES MADE TO THE LONG TERM THIS PACKAGE. ON MONDAY
THE WEDGE SHOULD ERODE IN ADVANCE OF THE NEXT APPROACHING COLD
FRONT. FORECASTED A CHANCE OF SHOWERS ASSOCIATED WITH THIS FRONT.
DRYING BEHIND THE FRONT APPEARED TO DOMINATE TUESDAY INTO
WEDNESDAY. KEPT A SMALL POP IN THE FORECAST BECAUSE OF TIMING
UNCERTAINTY ASSOCIATED WITH THE WARM ADVECTION PATTERN AHEAD OF
THE NEXT SYSTEM. THE GFS ENSEMBLES HAVE SHOWN A HIGH SPREAD IN THE
FAST FLOW. KEPT CHANCE POPS DURING THE REST OF THE EXTENDED
PERIOD. THE GFS SHOWED THE APPROACHING COLD FRONT REACHING THE
FORECAST AREA FRIDAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
WARM FRONT MOVING NORTHWARD ACROSS THE CENTRAL SC MIDLANDS EARLY
THIS MORNING. ISENTROPIC LIFT OVER REGION LEADING TO LIGHT RAIN OR
LIGHT SHOWERS ACROSS THE REGION. SOME BRIEF MVFR CONDITIONS POSSIBLE
IN HEAVIER SHOWERS BEFORE 14Z THIS MORNING. AS THE WARM FRONT
CONTINUES TO MOVE NORTHWARD...LOW LEVEL WINDS INCREASE 1-2 KFT TO
220 AT 40 KNOTS AND LOW LEVEL WIND SHEAR IS POSSIBLE FROM 12Z-14Z
EARLY THIS MORNING. COMPOSITE REGIONAL RADAR INDICATING MORE SHOWERS
DEVELOPING OVER NORTHERN GA WHICH WILL MOVE INTO SC LATER THIS
MORNING. AFTER AROUND 18Z...WARM AIR ADVECTION IS EXPECTED TO ALLOW
STRONGER WINDS TO REACH THE SURFACE WITH GUSTY SOUTHWEST WINDS 15-25
KNOTS THUS DECREASING THE EFFECTIVE WIND SHEAR BUT INCREASING THE
POSSIBILITY OF LOW LEVEL TURBULENCE. SOME IFR-MVFR CONDITIONS ARE
POSSIBLE LATER DURING THE AFTERNOON AS A COLD FRONT APPROACHES AND
THE CHANCES FOR TSTMS INCREASE. A LINE OF THUNDERSTORMS OR POSSIBLY
A SQUALL LINE MAY DEVELOP BY LATE AFTERNOON/EARLY EVENING. SPC HAS
CAE FA OUTLOOKED FOR A SLIGHT RISK OF SEVERE STORMS TODAY WITH THE
MAIN THREAT BEING DAMAGING WINDS. CONVECTIVE ACTIVITY SHOULD
DIMINISH DURING THE EVENING HOURS. WINDS WILL BECOME MORE VARIABLE
AFTER 06Z SUNDAY AS THE COLD FRONT MOVES EAST OF OUR AREA AND HIGH
PRESSURE BEGINS TO BUILD IN FROM THE NORTH. MAINLY MVFR CONDITIONS
EXPECTED AFTER 06Z AS DRIZZLE ALONG WITH SOME PATCHY FOG DEVELOP
AFTER 06Z SUNDAY. CANNOT RULE OUT SOME IFR CONDITIONS AFTER 06Z BUT
CONFIDENCE IS LOW TO MENTION AT THIS TIME.
EXTENDED AVIATION OUTLOOK...FRONT TO SLOWLY PASS EARLY SUNDAY
MORNING...WITH APPEARANCE OF WEAK WEDGE BUILDING DOWN BEHIND IT ON
SUNDAY. THIS WILL PROVIDE POTENTIAL FOR LOW CLOUDINESS...POSSIBLY
IFR...EARLY SUNDAY MORNING...INTO SUNDAY NIGHT. THE NEXT FRONT WILL
MOVE THROUGH MONDAY PROVIDING A CHANCE OF SHOWERS...AND ASSOCIATED
RESTRICTIONS. NO SIGNIFICANT IMPACTS TO AVIATION ARE EXPECTED LATE
MONDAY INTO WEDNESDAY...AS HIGH PRESSURE BUILDS IN.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
936 PM CST SUN JAN 22 2012
.DISCUSSION...
910 PM CST
NOT MUCH CHANGE TO THE GOING FORECAST THIS EVENING. TRENDS ARE
PANNING OUT AS EXPECTED AND ARE IN A MONITOR MODE WITH THE
CONVECTION TO THE SOUTH. ACROSS THE AREA...VAD WIND PROFILE SHOW
WINDS AT 1KFT GENERALLY OUT OF THE SOUTHEAST AT 20 OR SO KT...AND
AT 3KFT...SOUTH TO SOUTHWEST AT 50 TO 55KT. MODEL PROGS SHOW THAT
THE LLJ WILL CONTINUE TO INCREASE AND WILL GIVE ANY STORMS THAT
WORK THROUGH...THE POTENTIAL BE STRONG. MID LEVEL LAPSE RATES HAD
BEEN PROGGED TO RANGE FROM 6-7.5 C/KM THIS EVE...BUT RUC ANALYSIS
SHOWED THAT BEING ON THE WANE AS OF 03Z...WITH THE HIGHEST VALUES
SHIFTING EAST. DESPITE THE SURGE OF WARMTH AND
MOISTURE...CONVECTION WILL HAVE TO STRUGGLE AGAINST A STABLE
SURFACE AIRMASS. THE BEST FOCUS STILL SET TO REMAIN SOUTH FOR
SEVERE ACTIVITY...WITH THE BEST FOCUS LOCALLY...GENERALLY EAST OF
THE I-57 CORRIDOR THROUGH THE MIDNIGHT HOUR WHERE A FEW RUMBLES OF
THUNDER MAY BE HEARD. LATEST GRIDS AND ZONES ARE OUT. SHEA
//PREV DISCUSSION...
357 PM CST
JUST 48 HOURS AFTER A WINTER STORM...THE WEATHER WILL SWING
VIGOROUSLY THE OTHER WAY ACROSS THE MIDDLE OF THE COUNTRY
TONIGHT. MUCH OF THE ATTENTION ON THE FORECAST WAS SPENT ON THE
PRESENT THROUGH MONDAY...WITH CONCERNS ON DENSE FOG...INITIAL
FREEZING DRIZZLE...CONVECTION...GUSTY WINDS...AND SOME SNOW TO
ROUND IT OUT DURING MONDAY.
SYNOPSIS...THE WELL-DEFINED UPPER LOW IS TAKING BETTER SHAPE OVER
THE CENTRAL PLAINS THIS AFTERNOON...WITH SIGNS OF A STRONG MID-
LEVEL JET AND DRY SLOT DEVELOPING INTO THE OZARKS. THE SURFACE LOW
AT 992 MB OVER EASTERN KS HAS BEEN SLIGHTLY DEEPER THAN SOME OF
THE MODELS HAD INDICATED FOR THIS AFTERNOON. THE PRIMARY SURFACE
THETA-E GRADIENT IS DRAPED FROM NORTHERN MO INTO SOUTHERN IL.
LOW-LEVEL FLOW HAS BEEN INCREASING OVER THE FORECAST AREA...WHICH
IN PLACES HAS CAUSED SOME BLOWING AND DRIFTING OF THE LIGHT AND
FLUFFY SNOW SEEN THIS PAST FRIDAY. TEMPERATURES HAVE RESPONDED TO
THE RETURN FLOW AS WELL...CLIMBING INTO THE MID 30S ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA. INCREASING SURFACE
TEMPERATURES AND DEW POINTS WILL CONTINUE INTO TONIGHT...WITH THE
PRIMARY GRADIENT MARCHING MORE QUICKLY NORTH THROUGH IL AND IN
THAN IT HAD TODAY AS CYCLOGENESIS FURTHER OCCURS. THE SURFACE LOW
WILL SHIFT NORTHEAST TO NEAR THE QUAD CITIES BY 3 AM AS THE UPPER
TROUGH BECOMES NEGATIVELY TILED. THE COLD FRONT WILL PUSH QUICKLY
FROM SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA BETWEEN 3 AM
AND 7 AM...WITH LIKELY AN AREA OF SHOWERS AND CONVECTION AHEAD OF
IT BETWEEN 10 PM AND 3 AM. THE LOW WILL THEN SHIFT ON TO THE
NORTHERN PART OF LAKE MICHIGAN BY LATE MONDAY...KEEPING WESTERLY
WINDS GUSTY HERE.
DRIZZLE/FOG/BLOWING SNOW TONIGHT...THE EXPANSION OF DRIZZLE
ACROSS THE AREA EARLY THIS AFTERNOON LINED UP WELL WITH SATURATION
AND SOME WEAK ADIABATIC OMEGA ON THE 275K AND 280K SURFACES.
CONTINUING TO LOOK AT NEAR-SURFACE LAYERS INTO TONIGHT ON THE
RUC...THE PROJECTION IS FOR THE GREATER LIFT IN SATURATION TO MOVE
NORTH OF THE AREA BY EARLY TO MID EVENING. IN ADDITION...THE
SURFACE TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING IN ALL
AREAS BY 6 PM. IN THE DIRECT PATH OF THE LOW...TOWARDS
NORTHWEST/NORTH CENTRAL IL...THE WINDS WILL ACTUALLY BEGIN TO
DECREASE WITHIN THE INFLECTION IN THE PRESSURE PATTERN. THIS MAY
ALLOW CURRENT VISIBILITY TO FURTHER REDUCE FOR SOME DENSE FOG. AT
THIS POINT HAVE JUST HIGHLIGHTED WITH AREAS OF FOG TONIGHT. EXPECT
THAT WITH THE WINDS FORECAST TONIGHT SOME OF THIS SHALLOW
BLOWING/DRIFTING WILL CONTINUE IN RURAL AREAS. WILL MENTION IN THE
FORECAST AND MONITOR CLOSELY.
THUNDERSTORM CHANCES TONIGHT...AFTER A PRECIPITABLE WATER OF ONLY
0.20 ON THE MORNING ILX SOUNDING...A SIGNIFICANT REBOUND TO NEAR
1.1 INCHES IS EXPECTED TONIGHT ACROSS CENTRAL AND EASTERN IL INTO
IN. THIS IS PART OF AN ANOMALOUSLY STRONG LOW LEVEL JET...WHICH THE
22.12 NAM HAD AT SEVEN STANDARDIZED ANOMALIES ABOVE NORMAL. THIS
STRONG WIND FIELD IS WHAT WOULD GIVE ANY THUNDERSTORMS THE CHANCE
TO BE SEVERE...COMPENSATING FOR LIMITED LOW-LEVEL
INSTABILITY/FAVORABLE LAPSE RATES. MARGINAL INSTABILITY ALOFT IS
PRESENT...AT 500-1000 J/KG IN THE FAR SOUTHEAST/...HELPED BY
STRONG DIFFERENTIAL THETA-E ADVECTION WITH THE DRY SLOT INTRUSION.
THIS OVERRIDES THE SURFACE FOCUS OF A COLD FRONT /AND POSSIBLY A
PRE-FRONTAL TROUGH JUST AHEAD OF THIS/...WHICH SHOULD HELP
CONVECTION TO DEVELOP AND EVOLVE DURING THE 7 PM TO 10 PM TIME
ACROSS SOUTHWEST INTO CENTRAL IL.
BOUNDARY LAYER DEW POINTS IN EXCESS OF 50F ARE PROJECTED BY THE
NAM/GFS TO BE NEAR THE SOUTHEAST FORECAST AREA EDGE...WHICH WILL
KEEP THE LOWER PROFILES MOIST BASED ON FORECAST SOUNDINGS. GIVEN
THE VERY CLOSE PROXIMITY OF THE SNOW COVER EDGE BASED ON THIS
MORNINGS OBSERVATIONS...EVEN HIGHER TEMPERATURE AND DEW POINTS
/BUT WITH THE SAME LOW TEMP AND DEW POINT SPREADS/ MAY BE SEEN
INTO THE SOUTHEAST FORECAST AREA. THIS SETUP WOULD FURTHER HELP
FOR WINDS TO PUNCH THE INVERSION AND MAKE IT TO THE SURFACE WITHIN
SHOWERS AND ESPECIALLY ORGANIZED THUNDERSTORMS. FORECAST NAM
SOUNDINGS AT CHAMPAIGN SHOW ALMOST 70 KTS AND 3000 FT...SO PLENTY
AVAILABLE TO MIX DOWN. THIS SETUP WILL NEED TO BE WATCHED TOO FOR
THE CHANCE OF A TORNADO AS FAR NORTH AS OUR SOUTHEAST FORECAST
AREA...AS FORECAST PROFILES AND SYNOPTICS APPROACH THOSE THAT CAN
PRODUCE COOL SEASON EPISODES.
TO THE NORTH OF THE SEVERE CONVECTIVE THREAT...RAIN SHOWERS ARE
EXPECTED WITH POTENTIAL THUNDER. SOME OF THE RAINFALL RATES COULD
BE TEMPORARILY HEAVY...WHICH COULD FURTHER AGGRAVATE RUNOFF
ALREADY HEIGHTENED FROM SNOW MELT TONIGHT.
MONDAY...THE COLD AIR ADVECTION WILL WRAP IN QUICKLY BEHIND THE
FRONT. PARAMETERS FOR GUSTY WINDS...SUCH AS STEEPENED LOW-LEVEL
LAPSE RATES AND STRONG LOW-LEVEL Q-VECTOR DIVERGENCE...ARE BEST
SEEN IN THE SOUTHERN FORECAST AREA. WIND GUSTS TO NEAR 40 MPH ARE
EXPECTED AND IT IS POSSIBLE A WIND ADVISORY WILL BE NEEDED IN
TIME. THE SOUTHERN PART OF THE OVERALL UPPER TROUGH WILL MOVE
ACROSS THE AREA...LIKELY PRODUCING SOME SNOW FOR NORTHERN AREAS.
SOME MINOR ACCUMULATION UP TO POSSIBLY AN INCH COULD OCCUR NEAR
THE STATE LINE. BY MID TO LATE AFTERNOON...DEEP NVA IS FORECAST
WHICH SHOULD END ANY LIGHT SNOW/FLURRIES. CLOUDS WILL BE SLOWER TO
CLEAR...WITH SOME STILL HOLDING ON IN NORTHERN AND EASTERN AREAS
ON TUESDAY MORNING.
BEYOND...LITTLE CHANGES MADE TO THIS PORTION OF THE
FORECAST...WHICH LOOKS RELATIVE QUIET COMPARED TO THE PAST TEN
DAYS. A BLEND OF THE BETTER PERFORMING MODELS AND THE GOING FORECAST
WAS PRUDENT AT THIS TIME.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* IFR/LIFR VIS/CIG CONDITIONS IN DRIZZLE/FOG THIS EVENING.
* INCREASING POTENTIAL FOR PERIODS OF HEAVIER RAIN BY LATE
EVENING/MIDNIGHT.
* POTENTIAL FOR THUNDERSTORMS NEAR AND SOUTH/SOUTHEAST OF ORD/MDW
LATE EVENING/OVERNIGHT.
* LLWS THIS EVENING WITH 50-60 KT SSW WINDS 1500-2000 FT AGL.
* BRISK SOUTHEAST WINDS SHIFTING SOUTH OVERNIGHT...THEN SOUTHWEST
TOWARD MORNING. GUSTS INCREASING TO 30-35 KT FROM THE WEST-
SOUTHWEST MONDAY.
* LINGERING RAIN MIXING/CHANGING TO LIGHT SNOW MONDAY MORNING.
RATZER
//DISCUSSION...UPDATED 0330Z...
HAVE AMENDED ORD/DPA TO INCLUDE VCTS FOR A TIME 0430-0700Z AND
HAVE INCLUDED TEMPOS FOR SIMILAR PERIODS FOR MDW/GYY. TSRA
CONTINUES TO EXPAND UPSTREAM FROM THE INTERSTATE 55 CORRIDOR
EASTWARD.
RATZER
PREVIOUS DISCUSSION FROM 03Z...
WARM/MOIST AIR CONTINUES TO SURGE NORTHWARD ACROSS IL/IN IN ADVANCE
OF DEEP AREA OF LOW PRESSURE CENTERED OVER FAR WESTERN MO AT 03Z.
WITHIN THIS PLUME OF WARM/MOIST AIR...ELEVATED INSTABILITY AND
STRONG FORCING FOR ASCENT ARE COMBINING TO PRODUCE SCATTERED
CONVECTIVE SHOWERS AS FAR NORTHEAST AS CHICAGO METRO AREA...AND
THUNDERSTORMS FROM ARKANSAS AND SOUTHEAST MO INTO EAST CENTRAL IL.
HIGH RESOLUTION HRRR RUNS CONTINUE TO SHOW GOOD RUN TO RUN
CONSISTENCY THIS EVENING...SUGGESTING GREATEST POTENTIAL FOR MORE
WIDESPREAD THUNDERSTORMS WILL LIKELY REMAIN EAST/SOUTH OF THE
ORD/MDW TERMINALS...THOUGH RAIN/SHOWERS AND POSSIBLY SOME EMBEDDED
THUNDER WILL LIKELY DEVELOP/INCREASE IN COVERAGE INTO NORTHEAST IL
BY 05-07Z. IN ADDITION...SOME TSRA HAVE BEEN OVER/EAST OF THE KANSAS
CITY AREA THIS EVENING...DIRECTLY BENEATH UPPER TROUGH. LATEST HRRR
PROGS INDICATE THIS COULD POTENTIALLY AFFECT PARTS OF FAR NORTHERN
IL AROUND 12Z OR SO AS THE NEGATIVELY TILTED UPPER TROUGH AXIS LIFTS
NORTHEAST ACROSS THE AREA. FOR NOW...LIFR CIGS AND VSBYS GENERALLY
IN THE 1-2SM RANGE ARE EXPECTED TO CONTINUE. INCREASING COVERAGE OF
SHOWERS MAY HELP RAISE VISIBILITY A BIT OVERNIGHT...BUT MORE
RELIABLE IMPROVEMENT WILL LIKELY HAVE TO WAIT FOR PRE-FRONTAL TROUGH
PASSAGE MONDAY MORNING.
RATZER
PREVIOUS DISCUSSION FROM 00Z...
VERY LITTLE CHANGE TO THINKING FROM PREVIOUS FORECAST ISSUANCE...
WITH ONLY SOME MINOR TWEAKING OF NEAR TERM CIG/VIS PER CURRENT
REGIONAL OBSERVATIONS.
LOW PRESSURE CONTINUES TO DEEPEN ACROSS FAR EASTERN KANSAS EARLY
THIS EVENING...IN RESPONSE TO STRONG MID-LEVEL DISTURBANCE
ROUNDING BASE OF UPPER TROUGH OVER THE SOUTHERN/CENTRAL PLAINS.
UNSEASONABLY MOIST/WARM AIR IS BEING PULLED NORTH ACROSS THE
MIDWEST IN RESPONSE TO THIS LOW PRESSURE SYSTEM...RESULTING IN
WIDESPREAD LOW STRATUS...DRIZZLE AND FOG DEVELOPMENT AS MOISTURE
SPREADS ATOP COLD GROUND AND SNOW PACK. AS SURFACE/UPPER LOW
PRESSURE SYSTEMS LIFT NORTHEAST ACROSS THE REGION OVERNIGHT...
STEADIER RAIN IS EXPECTED TO DEVELOP WHICH MAY HELP IMPROVE
VISIBILITY A BIT. HOWEVER...UNSEASONABLY WARM/MOIST AND UNSTABLE
AIR WILL ALSO BE PULLED INTO THE GREAT LAKES REGION LATE TONIGHT
WHICH COMBINED WITH STRONG FORCING AND WIND FIELDS WITH THIS
VIGOROUS STORM SYSTEM MAY ALSO RESULT IN THE POTENTIAL FOR
SCATTERED THUNDERSTORMS...PARTICULARLY EAST/SOUTHEAST OF CHICAGO.
LOCALIZED HEAVIER RAINFALL AND STRONG WIND GUSTS WILL BE POSSIBLE
WITH SOME OF THESE STORMS. CONFIDENCE ON THUNDER OCCURRING AS FAR
NORTHWEST AS ORD/MDW NOT HIGH...THOUGH IT IS CERTAINLY POSSIBLE
AND WILL CONTINUE TO MONITOR CURRENT CONVECTION DEVELOPING OVER
ARKANSAS AND SOUTHEAST MISSOURI AS IT RAPIDLY MOVES NORTHEAST THIS
EVENING.
LOW LEVEL NON-CONVECTIVE WIND SHEAR WILL LIKELY BE AN ISSUE THIS
EVENING...AS WINDS IN THE 1500-2000 FT RANGE ARE EXPECTED TO BE
SOUTH-SOUTHWEST IN THE 50-60 KT RANGE...WHILE SFC WINDS WILL BE
SOUTHEAST IN THE 12-20 KT RANGE. 00Z RAOB FROM DOWNSTATE ILX
ALREADY SHOWING 50+ KTS AT THAT LEVEL...SO LLWS APPEARS A GOOD
BET. WINDS EVENTUALLY SLACK OFF TO 30-40 KTS ABOVE THE INVERSION
DURING THE PRE-DAWN HOURS...AND LLWS SHOULD NOT BE A FACTOR BY
MONDAY MORNING WHEN PRE-FRONTAL TROUGH AND COLD FRONT PUSH
THROUGH.
TROUGH/FRONTAL PASSAGE MONDAY MORNING WILL SHIFT WINDS TO THE
SOUTHWEST INITIALLY...THEN WEST-NORTHWEST BY LATER IN THE MORNING.
COLD ADVECTION AND STEEPENING LOW LEVEL LAPSE RATES WILL ALLOW FOR
MIXING OF HIGHER MOMENTUM AIR TO THE SURFACE...WITH GUSTS IN THE
30-35 KT RANGE BY AFTERNOON. IN ADDITION...ANY LINGERING LIGHT
RAIN WILL CHANGE TO LIGHT SNOW OR SNOW SHOWERS BY MID-MORNING AS
COLUMN COOLS. SOME MINOR ACCUMULATION POSSIBLE...BUT LESS THAN A
HALF INCH EXPECTED.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN CONTINUED LIFR CIGS AND VIS 1 TO 1 1/2SM THIS
EVENING. MEDIUM CONFIDENCE IN SOME VIS IMPROVEMENT IN STEADIER
RAIN LATER THIS EVENING/OVERNIGHT.
* LOW CONFIDENCE IN TSRA DIRECTLY IMPACTING ORD/MDW LATE
EVENING...BUT HIGH CONFIDENCE TSRA WILL OCCUR IN EAST/SOUTHEAST
ARRIVAL/DEPARTURE AIRSPACE ACROSS IN/MI. HIGH CONFIDENCE IN
INCREASE IN SHRA COVERAGE OVERNIGHT OVER TERMINALS HOWEVER.
* HIGH CONFIDENCE IN LLWS CONDITIONS THROUGH THIS EVENING.
* HIGH CONFIDENCE IN WIND DIRECTION AND TIMING OF WIND SHIFTS AS
WELL AS WESTERLY WIND GUSTS TO/ABOVE 30 KTS MONDAY AFTERNOON.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...SLIGHT CHANCE OF SNOW SHOWERS LATE...MAINLY VFR.
SATURDAY...VFR.
RATZER
&&
.MARINE...
240 PM CST
DEEP AREA OF LOW PRESSURE WILL LIFT NORTH ACROSS LAKE MICHIGAN
OVERNIGHT WITH STRONG SOUTHERLY WINDS AHEAD OF THE LOW BECOMING
SOUTHWEST AS THE LOW SWEEPS ACROSS THE LAKE. LOW END GALES ARE
POSSIBLE ACROSS CENTRAL PORTIONS OF THE LAKE THROUGH THIS
EVENING...AND WILL ADVECT MOIST DEWPOINTS OVER THE LAKE SETTING UP
THE POTENTIAL FOR DENSE FOG...AS WELL AS THUNDERSTORMS ACROSS THE
SOUTHERN PORTIONS OF THE LAKE. EXPECT A BRIEF LULL IN THE GALES AS
THE PRESSURE GRADIENT BECOMES MORE BAGGY NEAR THE LOW CENTER...
BEFORE STRONGER GALES RESUME MONDAY MORNING. COLD AIR SWEEPING
ACROSS THE LAKE WILL ALLOW FOR DEEP MIXING AND 40 TO 45 KT GALES ARE
EXPECTED...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE LAKE. REPLACED
THE SMALL CRAFT ADVISORY FOR THE NEARSHORE WATERS WITH A GALE WATCH
FOR MONDAY. WINDS BEGIN TO COME DOWN EARLY TUESDAY AS THE LOW LIFTS
AWAY FROM THE GREAT LAKES INTO QUEBEC AND HIGH PRESSURE BEGINS TO
BUILD INTO THE WESTERN GREAT LAKES REGION. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM MONDAY.
GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-
LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...2 PM MONDAY TO 2 AM TUESDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...8 PM MONDAY TO 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
913 PM CST SUN JAN 22 2012
.DISCUSSION...
910 PM CST
NOT MUCH CHANGE TO THE GOING FORECAST THIS EVENING. TRENDS ARE
PANNING OUT AS EXPECTED AND ARE IN A MONITOR MODE WITH THE
CONVECTION TO THE SOUTH. ACROSS THE AREA...VAD WIND PROFILE SHOW
WINDS AT 1KFT GENERALLY OUT OF THE SOUTHEAST AT 20 OR SO KT...AND
AT 3KFT...SOUTH TO SOUTHWEST AT 50 TO 55KT. MODEL PROGS SHOW THAT
THE LLJ WILL CONTINUE TO INCREASE AND WILL GIVE ANY STORMS THAT
WORK THROUGH...THE POTENTIAL BE STRONG. MID LEVEL LAPSE RATES HAD
BEEN PROGGED TO RANGE FROM 6-7.5 C/KM THIS EVE...BUT RUC ANALYSIS
SHOWED THAT BEING ON THE WANE AS OF 03Z...WITH THE HIGHEST VALUES
SHIFTING EAST. DESPITE THE SURGE OF WARMTH AND
MOISTURE...CONVECTION WILL HAVE TO STRUGGLE AGAINST A STABLE
SURFACE AIRMASS. THE BEST FOCUS STILL SET TO REMAIN SOUTH FOR
SEVERE ACTIVITY...WITH THE BEST FOCUS LOCALLY...GENERALLY EAST OF
THE I-57 CORRIDOR THROUGH THE MIDNIGHT HOUR WHERE A FEW RUMBLES OF
THUNDER MAY BE HEARD. LATEST GRIDS AND ZONES ARE OUT. SHEA
//PREV DISCUSSION...
357 PM CST
JUST 48 HOURS AFTER A WINTER STORM...THE WEATHER WILL SWING
VIGOROUSLY THE OTHER WAY ACROSS THE MIDDLE OF THE COUNTRY
TONIGHT. MUCH OF THE ATTENTION ON THE FORECAST WAS SPENT ON THE
PRESENT THROUGH MONDAY...WITH CONCERNS ON DENSE FOG...INITIAL
FREEZING DRIZZLE...CONVECTION...GUSTY WINDS...AND SOME SNOW TO
ROUND IT OUT DURING MONDAY.
SYNOPSIS...THE WELL-DEFINED UPPER LOW IS TAKING BETTER SHAPE OVER
THE CENTRAL PLAINS THIS AFTERNOON...WITH SIGNS OF A STRONG MID-
LEVEL JET AND DRY SLOT DEVELOPING INTO THE OZARKS. THE SURFACE LOW
AT 992 MB OVER EASTERN KS HAS BEEN SLIGHTLY DEEPER THAN SOME OF
THE MODELS HAD INDICATED FOR THIS AFTERNOON. THE PRIMARY SURFACE
THETA-E GRADIENT IS DRAPED FROM NORTHERN MO INTO SOUTHERN IL.
LOW-LEVEL FLOW HAS BEEN INCREASING OVER THE FORECAST AREA...WHICH
IN PLACES HAS CAUSED SOME BLOWING AND DRIFTING OF THE LIGHT AND
FLUFFY SNOW SEEN THIS PAST FRIDAY. TEMPERATURES HAVE RESPONDED TO
THE RETURN FLOW AS WELL...CLIMBING INTO THE MID 30S ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA. INCREASING SURFACE
TEMPERATURES AND DEW POINTS WILL CONTINUE INTO TONIGHT...WITH THE
PRIMARY GRADIENT MARCHING MORE QUICKLY NORTH THROUGH IL AND IN
THAN IT HAD TODAY AS CYCLOGENESIS FURTHER OCCURS. THE SURFACE LOW
WILL SHIFT NORTHEAST TO NEAR THE QUAD CITIES BY 3 AM AS THE UPPER
TROUGH BECOMES NEGATIVELY TILED. THE COLD FRONT WILL PUSH QUICKLY
FROM SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA BETWEEN 3 AM
AND 7 AM...WITH LIKELY AN AREA OF SHOWERS AND CONVECTION AHEAD OF
IT BETWEEN 10 PM AND 3 AM. THE LOW WILL THEN SHIFT ON TO THE
NORTHERN PART OF LAKE MICHIGAN BY LATE MONDAY...KEEPING WESTERLY
WINDS GUSTY HERE.
DRIZZLE/FOG/BLOWING SNOW TONIGHT...THE EXPANSION OF DRIZZLE
ACROSS THE AREA EARLY THIS AFTERNOON LINED UP WELL WITH SATURATION
AND SOME WEAK ADIABATIC OMEGA ON THE 275K AND 280K SURFACES.
CONTINUING TO LOOK AT NEAR-SURFACE LAYERS INTO TONIGHT ON THE
RUC...THE PROJECTION IS FOR THE GREATER LIFT IN SATURATION TO MOVE
NORTH OF THE AREA BY EARLY TO MID EVENING. IN ADDITION...THE
SURFACE TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING IN ALL
AREAS BY 6 PM. IN THE DIRECT PATH OF THE LOW...TOWARDS
NORTHWEST/NORTH CENTRAL IL...THE WINDS WILL ACTUALLY BEGIN TO
DECREASE WITHIN THE INFLECTION IN THE PRESSURE PATTERN. THIS MAY
ALLOW CURRENT VISIBILITY TO FURTHER REDUCE FOR SOME DENSE FOG. AT
THIS POINT HAVE JUST HIGHLIGHTED WITH AREAS OF FOG TONIGHT. EXPECT
THAT WITH THE WINDS FORECAST TONIGHT SOME OF THIS SHALLOW
BLOWING/DRIFTING WILL CONTINUE IN RURAL AREAS. WILL MENTION IN THE
FORECAST AND MONITOR CLOSELY.
THUNDERSTORM CHANCES TONIGHT...AFTER A PRECIPITABLE WATER OF ONLY
0.20 ON THE MORNING ILX SOUNDING...A SIGNIFICANT REBOUND TO NEAR
1.1 INCHES IS EXPECTED TONIGHT ACROSS CENTRAL AND EASTERN IL INTO
IN. THIS IS PART OF AN ANOMALOUSLY STRONG LOW LEVEL JET...WHICH THE
22.12 NAM HAD AT SEVEN STANDARDIZED ANOMALIES ABOVE NORMAL. THIS
STRONG WIND FIELD IS WHAT WOULD GIVE ANY THUNDERSTORMS THE CHANCE
TO BE SEVERE...COMPENSATING FOR LIMITED LOW-LEVEL
INSTABILITY/FAVORABLE LAPSE RATES. MARGINAL INSTABILITY ALOFT IS
PRESENT...AT 500-1000 J/KG IN THE FAR SOUTHEAST/...HELPED BY
STRONG DIFFERENTIAL THETA-E ADVECTION WITH THE DRY SLOT INTRUSION.
THIS OVERRIDES THE SURFACE FOCUS OF A COLD FRONT /AND POSSIBLY A
PRE-FRONTAL TROUGH JUST AHEAD OF THIS/...WHICH SHOULD HELP
CONVECTION TO DEVELOP AND EVOLVE DURING THE 7 PM TO 10 PM TIME
ACROSS SOUTHWEST INTO CENTRAL IL.
BOUNDARY LAYER DEW POINTS IN EXCESS OF 50F ARE PROJECTED BY THE
NAM/GFS TO BE NEAR THE SOUTHEAST FORECAST AREA EDGE...WHICH WILL
KEEP THE LOWER PROFILES MOIST BASED ON FORECAST SOUNDINGS. GIVEN
THE VERY CLOSE PROXIMITY OF THE SNOW COVER EDGE BASED ON THIS
MORNINGS OBSERVATIONS...EVEN HIGHER TEMPERATURE AND DEW POINTS
/BUT WITH THE SAME LOW TEMP AND DEW POINT SPREADS/ MAY BE SEEN
INTO THE SOUTHEAST FORECAST AREA. THIS SETUP WOULD FURTHER HELP
FOR WINDS TO PUNCH THE INVERSION AND MAKE IT TO THE SURFACE WITHIN
SHOWERS AND ESPECIALLY ORGANIZED THUNDERSTORMS. FORECAST NAM
SOUNDINGS AT CHAMPAIGN SHOW ALMOST 70 KTS AND 3000 FT...SO PLENTY
AVAILABLE TO MIX DOWN. THIS SETUP WILL NEED TO BE WATCHED TOO FOR
THE CHANCE OF A TORNADO AS FAR NORTH AS OUR SOUTHEAST FORECAST
AREA...AS FORECAST PROFILES AND SYNOPTICS APPROACH THOSE THAT CAN
PRODUCE COOL SEASON EPISODES.
TO THE NORTH OF THE SEVERE CONVECTIVE THREAT...RAIN SHOWERS ARE
EXPECTED WITH POTENTIAL THUNDER. SOME OF THE RAINFALL RATES COULD
BE TEMPORARILY HEAVY...WHICH COULD FURTHER AGGRAVATE RUNOFF
ALREADY HEIGHTENED FROM SNOW MELT TONIGHT.
MONDAY...THE COLD AIR ADVECTION WILL WRAP IN QUICKLY BEHIND THE
FRONT. PARAMETERS FOR GUSTY WINDS...SUCH AS STEEPENED LOW-LEVEL
LAPSE RATES AND STRONG LOW-LEVEL Q-VECTOR DIVERGENCE...ARE BEST
SEEN IN THE SOUTHERN FORECAST AREA. WIND GUSTS TO NEAR 40 MPH ARE
EXPECTED AND IT IS POSSIBLE A WIND ADVISORY WILL BE NEEDED IN
TIME. THE SOUTHERN PART OF THE OVERALL UPPER TROUGH WILL MOVE
ACROSS THE AREA...LIKELY PRODUCING SOME SNOW FOR NORTHERN AREAS.
SOME MINOR ACCUMULATION UP TO POSSIBLY AN INCH COULD OCCUR NEAR
THE STATE LINE. BY MID TO LATE AFTERNOON...DEEP NVA IS FORECAST
WHICH SHOULD END ANY LIGHT SNOW/FLURRIES. CLOUDS WILL BE SLOWER TO
CLEAR...WITH SOME STILL HOLDING ON IN NORTHERN AND EASTERN AREAS
ON TUESDAY MORNING.
BEYOND...LITTLE CHANGES MADE TO THIS PORTION OF THE
FORECAST...WHICH LOOKS RELATIVE QUIET COMPARED TO THE PAST TEN
DAYS. A BLEND OF THE BETTER PERFORMING MODELS AND THE GOING FORECAST
WAS PRUDENT AT THIS TIME.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* IFR/LIFR VIS/CIG CONDITIONS IN DRIZZLE/FOG THIS EVENING.
* INCREASING POTENTIAL FOR PERIODS OF HEAVIER RAIN BY LATE
EVENING/MIDNIGHT.
* POTENTIAL FOR THUNDERSTORMS NEAR AND SOUTH/SOUTHEAST OF ORD/MDW
LATE EVENING/OVERNIGHT.
* LLWS THIS EVENING WITH 50-60 KT SSW WINDS 1500-2000 FT AGL.
* BRISK SOUTHEAST WINDS SHIFTING SOUTH OVERNIGHT...THEN SOUTHWEST
TOWARD MORNING. GUSTS INCREASING TO 30-35 KT FROM THE WEST-
SOUTHWEST MONDAY.
* LINGERING RAIN MIXING/CHANGING TO LIGHT SNOW MONDAY MORNING.
RATZER
//DISCUSSION...UPDATED 03Z...
WARM/MOIST AIR CONTINUES TO SURGE NORTHWARD ACROSS IL/IN IN ADVANCE
OF DEEP AREA OF LOW PRESSURE CENTERED OVER FAR WESTERN MO AT 03Z.
WITHIN THIS PLUME OF WARM/MOIST AIR...ELEVATED INSTABILITY AND
STRONG FORCING FOR ASCENT ARE COMBINING TO PRODUCE SCATTERED
CONVECTIVE SHOWERS AS FAR NORTHEAST AS CHICAGO METRO AREA...AND
THUNDERSTORMS FROM ARKANSAS AND SOUTHEAST MO INTO EAST CENTRAL IL.
HIGH RESOLUTION HRRR RUNS CONTINUE TO SHOW GOOD RUN TO RUN
CONSISTENCY THIS EVENING...SUGGESTING GREATEST POTENTIAL FOR MORE
WIDESPREAD THUNDERSTORMS WILL LIKELY REMAIN EAST/SOUTH OF THE
ORD/MDW TERMINALS...THOUGH RAIN/SHOWERS AND POSSIBLY SOME EMBEDDED
THUNDER WILL LIKELY DEVELOP/INCREASE IN COVERAGE INTO NORTHEAST IL
BY 05-07Z. IN ADDITION...SOME TSRA HAVE BEEN OVER/EAST OF THE KANSAS
CITY AREA THIS EVENING...DIRECTLY BENEATH UPPER TROUGH. LATEST HRRR
PROGS INDICATE THIS COULD POTENTIALLY AFFECT PARTS OF FAR NORTHERN
IL AROUND 12Z OR SO AS THE NEGATIVELY TILTED UPPER TROUGH AXIS LIFTS
NORTHEAST ACROSS THE AREA. FOR NOW...LIFR CIGS AND VSBYS GENERALLY
IN THE 1-2SM RANGE ARE EXPECTED TO CONTINUE. INCREASING COVERAGE OF
SHOWERS MAY HELP RAISE VISIBILITY A BIT OVERNIGHT...BUT MORE
RELIABLE IMPROVEMENT WILL LIKELY HAVE TO WAIT FOR PRE-FRONTAL TROUGH
PASSAGE MONDAY MORNING.
RATZER
PREVIOUS DISCUSSION FROM 00Z...
VERY LITTLE CHANGE TO THINKING FROM PREVIOUS FORECAST ISSUANCE...
WITH ONLY SOME MINOR TWEAKING OF NEAR TERM CIG/VIS PER CURRENT
REGIONAL OBSERVATIONS.
LOW PRESSURE CONTINUES TO DEEPEN ACROSS FAR EASTERN KANSAS EARLY
THIS EVENING...IN RESPONSE TO STRONG MID-LEVEL DISTURBANCE
ROUNDING BASE OF UPPER TROUGH OVER THE SOUTHERN/CENTRAL PLAINS.
UNSEASONABLY MOIST/WARM AIR IS BEING PULLED NORTH ACROSS THE
MIDWEST IN RESPONSE TO THIS LOW PRESSURE SYSTEM...RESULTING IN
WIDESPREAD LOW STRATUS...DRIZZLE AND FOG DEVELOPMENT AS MOISTURE
SPREADS ATOP COLD GROUND AND SNOW PACK. AS SURFACE/UPPER LOW
PRESSURE SYSTEMS LIFT NORTHEAST ACROSS THE REGION OVERNIGHT...
STEADIER RAIN IS EXPECTED TO DEVELOP WHICH MAY HELP IMPROVE
VISIBILITY A BIT. HOWEVER...UNSEASONABLY WARM/MOIST AND UNSTABLE
AIR WILL ALSO BE PULLED INTO THE GREAT LAKES REGION LATE TONIGHT
WHICH COMBINED WITH STRONG FORCING AND WIND FIELDS WITH THIS
VIGOROUS STORM SYSTEM MAY ALSO RESULT IN THE POTENTIAL FOR
SCATTERED THUNDERSTORMS...PARTICULARLY EAST/SOUTHEAST OF CHICAGO.
LOCALIZED HEAVIER RAINFALL AND STRONG WIND GUSTS WILL BE POSSIBLE
WITH SOME OF THESE STORMS. CONFIDENCE ON THUNDER OCCURRING AS FAR
NORTHWEST AS ORD/MDW NOT HIGH...THOUGH IT IS CERTAINLY POSSIBLE
AND WILL CONTINUE TO MONITOR CURRENT CONVECTION DEVELOPING OVER
ARKANSAS AND SOUTHEAST MISSOURI AS IT RAPIDLY MOVES NORTHEAST THIS
EVENING.
LOW LEVEL NON-CONVECTIVE WIND SHEAR WILL LIKELY BE AN ISSUE THIS
EVENING...AS WINDS IN THE 1500-2000 FT RANGE ARE EXPECTED TO BE
SOUTH-SOUTHWEST IN THE 50-60 KT RANGE...WHILE SFC WINDS WILL BE
SOUTHEAST IN THE 12-20 KT RANGE. 00Z RAOB FROM DOWNSTATE ILX
ALREADY SHOWING 50+ KTS AT THAT LEVEL...SO LLWS APPEARS A GOOD
BET. WINDS EVENTUALLY SLACK OFF TO 30-40 KTS ABOVE THE INVERSION
DURING THE PRE-DAWN HOURS...AND LLWS SHOULD NOT BE A FACTOR BY
MONDAY MORNING WHEN PRE-FRONTAL TROUGH AND COLD FRONT PUSH
THROUGH.
TROUGH/FRONTAL PASSAGE MONDAY MORNING WILL SHIFT WINDS TO THE
SOUTHWEST INITIALLY...THEN WEST-NORTHWEST BY LATER IN THE MORNING.
COLD ADVECTION AND STEEPENING LOW LEVEL LAPSE RATES WILL ALLOW FOR
MIXING OF HIGHER MOMENTUM AIR TO THE SURFACE...WITH GUSTS IN THE
30-35 KT RANGE BY AFTERNOON. IN ADDITION...ANY LINGERING LIGHT
RAIN WILL CHANGE TO LIGHT SNOW OR SNOW SHOWERS BY MID-MORNING AS
COLUMN COOLS. SOME MINOR ACCUMULATION POSSIBLE...BUT LESS THAN A
HALF INCH EXPECTED.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN CONTINUED LIFR CIGS AND VIS 1 TO 1 1/2SM THIS
EVENING. MEDIUM CONFIDENCE IN SOME VIS IMPROVEMENT IN STEADIER
RAIN LATER THIS EVENING/OVERNIGHT.
* LOW CONFIDENCE IN TSRA DIRECTLY IMPACTING ORD/MDW LATE
EVENING...BUT HIGH CONFIDENCE TSRA WILL OCCUR IN EAST/SOUTHEAST
ARRIVAL/DEPARTURE AIRSPACE ACROSS IN/MI. HIGH CONFIDENCE IN
INCREASE IN SHRA COVERAGE OVERNIGHT OVER TERMINALS HOWEVER.
* HIGH CONFIDENCE IN LLWS CONDITIONS THROUGH THIS EVENING.
* HIGH CONFIDENCE IN WIND DIRECTION AND TIMING OF WIND SHIFTS AS
WELL AS WESTERLY WIND GUSTS TO/ABOVE 30 KTS MONDAY AFTERNOON.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...SLIGHT CHANCE OF SNOW SHOWERS LATE...MAINLY VFR.
SATURDAY...VFR.
RATZER
&&
.MARINE...
240 PM CST
DEEP AREA OF LOW PRESSURE WILL LIFT NORTH ACROSS LAKE MICHIGAN
OVERNIGHT WITH STRONG SOUTHERLY WINDS AHEAD OF THE LOW BECOMING
SOUTHWEST AS THE LOW SWEEPS ACROSS THE LAKE. LOW END GALES ARE
POSSIBLE ACROSS CENTRAL PORTIONS OF THE LAKE THROUGH THIS
EVENING...AND WILL ADVECT MOIST DEWPOINTS OVER THE LAKE SETTING UP
THE POTENTIAL FOR DENSE FOG...AS WELL AS THUNDERSTORMS ACROSS THE
SOUTHERN PORTIONS OF THE LAKE. EXPECT A BRIEF LULL IN THE GALES AS
THE PRESSURE GRADIENT BECOMES MORE BAGGY NEAR THE LOW CENTER...
BEFORE STRONGER GALES RESUME MONDAY MORNING. COLD AIR SWEEPING
ACROSS THE LAKE WILL ALLOW FOR DEEP MIXING AND 40 TO 45 KT GALES ARE
EXPECTED...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE LAKE. REPLACED
THE SMALL CRAFT ADVISORY FOR THE NEARSHORE WATERS WITH A GALE WATCH
FOR MONDAY. WINDS BEGIN TO COME DOWN EARLY TUESDAY AS THE LOW LIFTS
AWAY FROM THE GREAT LAKES INTO QUEBEC AND HIGH PRESSURE BEGINS TO
BUILD INTO THE WESTERN GREAT LAKES REGION. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM MONDAY.
GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-
LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...2 PM MONDAY TO 2 AM TUESDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...8 PM MONDAY TO 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
910 PM CST SUN JAN 22 2012
.DISCUSSION...
910 PM CST
NOT MUCH CHANGE TO THE GOING FORECAST THIS EVENING. TRENDS ARE
PANNING OUT AS EXPECTED AND ARE IN A MONITOR MODE WITH THE
CONVECTION TO THE SOUTH. ACROSS THE AREA...VAD WIND PROFILE SHOW
WINDS AT 1KFT GENERALLY OUT OF THE SOUTHEAST AT 20 OR SO KT...AND
AT 3KFT...SOUTH TO SOUTHWEST AT 50 TO 55KT. MODEL PROGS SHOW THAT
THE LLJ WILL CONTINUE TO INCREASE AND WILL GIVE ANY STORMS THAT
WORK THROUGH...THE POTENTIAL BE STRONG. MID LEVEL LAPSE RATES HAD
BEEN PROGGED TO RANGE FROM 6-7.5 C/KM THIS EVE...BUT RUC ANALYSIS
SHOWED THAT BEING ON THE WANE AS OF 03Z...WITH THE HIGHEST VALUES
SHIFTING EAST. DESPITE THE SURGE OF WARMTH AND
MOISTURE...CONVECTION WILL HAVE TO STRUGGLE AGAINST A STABLE
SURFACE AIRMASS. THE BEST FOCUS STILL SET TO REMAIN SOUTH FOR
SEVERE ACTIVITY...WITH THE BEST FOCUS LOCALLY...GENERALLY EAST OF
THE I-57 CORRIDOR THROUGH THE MIDNIGHT HOUR WHERE A FEW RUMBLES OF
THUNDER MAY BE HEARD. LATEST GRIDS AND ZONES ARE OUT. SHEA
&&
.PREV DISCUSSION...
357 PM CST
JUST 48 HOURS AFTER A WINTER STORM...THE WEATHER WILL SWING
VIGOROUSLY THE OTHER WAY ACROSS THE MIDDLE OF THE COUNTRY
TONIGHT. MUCH OF THE ATTENTION ON THE FORECAST WAS SPENT ON THE
PRESENT THROUGH MONDAY...WITH CONCERNS ON DENSE FOG...INITIAL
FREEZING DRIZZLE...CONVECTION...GUSTY WINDS...AND SOME SNOW TO
ROUND IT OUT DURING MONDAY.
SYNOPSIS...THE WELL-DEFINED UPPER LOW IS TAKING BETTER SHAPE OVER
THE CENTRAL PLAINS THIS AFTERNOON...WITH SIGNS OF A STRONG MID-
LEVEL JET AND DRY SLOT DEVELOPING INTO THE OZARKS. THE SURFACE LOW
AT 992 MB OVER EASTERN KS HAS BEEN SLIGHTLY DEEPER THAN SOME OF
THE MODELS HAD INDICATED FOR THIS AFTERNOON. THE PRIMARY SURFACE
THETA-E GRADIENT IS DRAPED FROM NORTHERN MO INTO SOUTHERN IL.
LOW-LEVEL FLOW HAS BEEN INCREASING OVER THE FORECAST AREA...WHICH
IN PLACES HAS CAUSED SOME BLOWING AND DRIFTING OF THE LIGHT AND
FLUFFY SNOW SEEN THIS PAST FRIDAY. TEMPERATURES HAVE RESPONDED TO
THE RETURN FLOW AS WELL...CLIMBING INTO THE MID 30S ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA. INCREASING SURFACE
TEMPERATURES AND DEW POINTS WILL CONTINUE INTO TONIGHT...WITH THE
PRIMARY GRADIENT MARCHING MORE QUICKLY NORTH THROUGH IL AND IN
THAN IT HAD TODAY AS CYCLOGENESIS FURTHER OCCURS. THE SURFACE LOW
WILL SHIFT NORTHEAST TO NEAR THE QUAD CITIES BY 3 AM AS THE UPPER
TROUGH BECOMES NEGATIVELY TILED. THE COLD FRONT WILL PUSH QUICKLY
FROM SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA BETWEEN 3 AM
AND 7 AM...WITH LIKELY AN AREA OF SHOWERS AND CONVECTION AHEAD OF
IT BETWEEN 10 PM AND 3 AM. THE LOW WILL THEN SHIFT ON TO THE
NORTHERN PART OF LAKE MICHIGAN BY LATE MONDAY...KEEPING WESTERLY
WINDS GUSTY HERE.
DRIZZLE/FOG/BLOWING SNOW TONIGHT...THE EXPANSION OF DRIZZLE
ACROSS THE AREA EARLY THIS AFTERNOON LINED UP WELL WITH SATURATION
AND SOME WEAK ADIABATIC OMEGA ON THE 275K AND 280K SURFACES.
CONTINUING TO LOOK AT NEAR-SURFACE LAYERS INTO TONIGHT ON THE
RUC...THE PROJECTION IS FOR THE GREATER LIFT IN SATURATION TO MOVE
NORTH OF THE AREA BY EARLY TO MID EVENING. IN ADDITION...THE
SURFACE TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING IN ALL
AREAS BY 6 PM. IN THE DIRECT PATH OF THE LOW...TOWARDS
NORTHWEST/NORTH CENTRAL IL...THE WINDS WILL ACTUALLY BEGIN TO
DECREASE WITHIN THE INFLECTION IN THE PRESSURE PATTERN. THIS MAY
ALLOW CURRENT VISIBILITY TO FURTHER REDUCE FOR SOME DENSE FOG. AT
THIS POINT HAVE JUST HIGHLIGHTED WITH AREAS OF FOG TONIGHT. EXPECT
THAT WITH THE WINDS FORECAST TONIGHT SOME OF THIS SHALLOW
BLOWING/DRIFTING WILL CONTINUE IN RURAL AREAS. WILL MENTION IN THE
FORECAST AND MONITOR CLOSELY.
THUNDERSTORM CHANCES TONIGHT...AFTER A PRECIPITABLE WATER OF ONLY
0.20 ON THE MORNING ILX SOUNDING...A SIGNIFICANT REBOUND TO NEAR
1.1 INCHES IS EXPECTED TONIGHT ACROSS CENTRAL AND EASTERN IL INTO
IN. THIS IS PART OF AN ANOMALOUSLY STRONG LOW LEVEL JET...WHICH THE
22.12 NAM HAD AT SEVEN STANDARDIZED ANOMALIES ABOVE NORMAL. THIS
STRONG WIND FIELD IS WHAT WOULD GIVE ANY THUNDERSTORMS THE CHANCE
TO BE SEVERE...COMPENSATING FOR LIMITED LOW-LEVEL
INSTABILITY/FAVORABLE LAPSE RATES. MARGINAL INSTABILITY ALOFT IS
PRESENT...AT 500-1000 J/KG IN THE FAR SOUTHEAST/...HELPED BY
STRONG DIFFERENTIAL THETA-E ADVECTION WITH THE DRY SLOT INTRUSION.
THIS OVERRIDES THE SURFACE FOCUS OF A COLD FRONT /AND POSSIBLY A
PRE-FRONTAL TROUGH JUST AHEAD OF THIS/...WHICH SHOULD HELP
CONVECTION TO DEVELOP AND EVOLVE DURING THE 7 PM TO 10 PM TIME
ACROSS SOUTHWEST INTO CENTRAL IL.
BOUNDARY LAYER DEW POINTS IN EXCESS OF 50F ARE PROJECTED BY THE
NAM/GFS TO BE NEAR THE SOUTHEAST FORECAST AREA EDGE...WHICH WILL
KEEP THE LOWER PROFILES MOIST BASED ON FORECAST SOUNDINGS. GIVEN
THE VERY CLOSE PROXIMITY OF THE SNOW COVER EDGE BASED ON THIS
MORNINGS OBSERVATIONS...EVEN HIGHER TEMPERATURE AND DEW POINTS
/BUT WITH THE SAME LOW TEMP AND DEW POINT SPREADS/ MAY BE SEEN
INTO THE SOUTHEAST FORECAST AREA. THIS SETUP WOULD FURTHER HELP
FOR WINDS TO PUNCH THE INVERSION AND MAKE IT TO THE SURFACE WITHIN
SHOWERS AND ESPECIALLY ORGANIZED THUNDERSTORMS. FORECAST NAM
SOUNDINGS AT CHAMPAIGN SHOW ALMOST 70 KTS AND 3000 FT...SO PLENTY
AVAILABLE TO MIX DOWN. THIS SETUP WILL NEED TO BE WATCHED TOO FOR
THE CHANCE OF A TORNADO AS FAR NORTH AS OUR SOUTHEAST FORECAST
AREA...AS FORECAST PROFILES AND SYNOPTICS APPROACH THOSE THAT CAN
PRODUCE COOL SEASON EPISODES.
TO THE NORTH OF THE SEVERE CONVECTIVE THREAT...RAIN SHOWERS ARE
EXPECTED WITH POTENTIAL THUNDER. SOME OF THE RAINFALL RATES COULD
BE TEMPORARILY HEAVY...WHICH COULD FURTHER AGGRAVATE RUNOFF
ALREADY HEIGHTENED FROM SNOW MELT TONIGHT.
MONDAY...THE COLD AIR ADVECTION WILL WRAP IN QUICKLY BEHIND THE
FRONT. PARAMETERS FOR GUSTY WINDS...SUCH AS STEEPENED LOW-LEVEL
LAPSE RATES AND STRONG LOW-LEVEL Q-VECTOR DIVERGENCE...ARE BEST
SEEN IN THE SOUTHERN FORECAST AREA. WIND GUSTS TO NEAR 40 MPH ARE
EXPECTED AND IT IS POSSIBLE A WIND ADVISORY WILL BE NEEDED IN
TIME. THE SOUTHERN PART OF THE OVERALL UPPER TROUGH WILL MOVE
ACROSS THE AREA...LIKELY PRODUCING SOME SNOW FOR NORTHERN AREAS.
SOME MINOR ACCUMULATION UP TO POSSIBLY AN INCH COULD OCCUR NEAR
THE STATE LINE. BY MID TO LATE AFTERNOON...DEEP NVA IS FORECAST
WHICH SHOULD END ANY LIGHT SNOW/FLURRIES. CLOUDS WILL BE SLOWER TO
CLEAR...WITH SOME STILL HOLDING ON IN NORTHERN AND EASTERN AREAS
ON TUESDAY MORNING.
BEYOND...LITTLE CHANGES MADE TO THIS PORTION OF THE
FORECAST...WHICH LOOKS RELATIVE QUIET COMPARED TO THE PAST TEN
DAYS. A BLEND OF THE BETTER PERFORMING MODELS AND THE GOING FORECAST
WAS PRUDENT AT THIS TIME.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* IFR/LIFR VIS/CIG CONDITIONS IN DRIZZLE/FOG THIS EVENING.
* INCREASING POTENTIAL FOR PERIODS OF HEAVIER RAIN BY LATE EVENING.
* POTENTIAL FOR THUNDERSTORMS NEAR AND SOUTH/SOUTHEAST OF ORD/MDW
LATE EVENING/OVERNIGHT.
* LLWS THIS EVENING WITH 50-60 KT SSW WINDS 1500-2000 FT AGL.
* BRISK SOUTHEAST WINDS SHIFTING SOUTH OVERNIGHT...THEN SOUTHWEST
TOWARD MORNING. GUSTS INCREASING TO 30-35 KT FROM THE WEST-
SOUTHWEST MONDAY.
* LINGERING RAIN MIXING/CHANGING TO LIGHT SNOW MONDAY MORNING.
RATZER
//DISCUSSION...UPDATED 00Z...
VERY LITTLE CHANGE TO THINKING FROM PREVIOUS FORECAST ISSUANCE...
WITH ONLY SOME MINOR TWEAKING OF NEAR TERM CIG/VIS PER CURRENT
REGIONAL OBSERVATIONS.
LOW PRESSURE CONTINUES TO DEEPEN ACROSS FAR EASTERN KANSAS EARLY
THIS EVENING...IN RESPONSE TO STRONG MID-LEVEL DISTURBANCE
ROUNDING BASE OF UPPER TROUGH OVER THE SOUTHERN/CENTRAL PLAINS.
UNSEASONABLY MOIST/WARM AIR IS BEING PULLED NORTH ACROSS THE
MIDWEST IN RESPONSE TO THIS LOW PRESSURE SYSTEM...RESULTING IN
WIDESPREAD LOW STRATUS...DRIZZLE AND FOG DEVELOPMENT AS MOISTURE
SPREADS ATOP COLD GROUND AND SNOW PACK. AS SURFACE/UPPER LOW
PRESSURE SYSTEMS LIFT NORTHEAST ACROSS THE REGION OVERNIGHT...
STEADIER RAIN IS EXPECTED TO DEVELOP WHICH MAY HELP IMPROVE
VISIBILITY A BIT. HOWEVER...UNSEASONABLY WARM/MOIST AND UNSTABLE
AIR WILL ALSO BE PULLED INTO THE GREAT LAKES REGION LATE TONIGHT
WHICH COMBINED WITH STRONG FORCING AND WIND FIELDS WITH THIS
VIGOROUS STORM SYSTEM MAY ALSO RESULT IN THE POTENTIAL FOR
SCATTERED THUNDERSTORMS...PARTICULARLY EAST/SOUTHEAST OF CHICAGO.
LOCALIZED HEAVIER RAINFALL AND STRONG WIND GUSTS WILL BE POSSIBLE
WITH SOME OF THESE STORMS. CONFIDENCE ON THUNDER OCCURRING AS FAR
NORTHWEST AS ORD/MDW NOT HIGH...THOUGH IT IS CERTAINLY POSSIBLE
AND WILL CONTINUE TO MONITOR CURRENT CONVECTION DEVELOPING OVER
ARKANSAS AND SOUTHEAST MISSOURI AS IT RAPIDLY MOVES NORTHEAST THIS
EVENING.
LOW LEVEL NON-CONVECTIVE WIND SHEAR WILL LIKELY BE AN ISSUE THIS
EVENING...AS WINDS IN THE 1500-2000 FT RANGE ARE EXPECTED TO BE
SOUTH-SOUTHWEST IN THE 50-60 KT RANGE...WHILE SFC WINDS WILL BE
SOUTHEAST IN THE 12-20 KT RANGE. 00Z RAOB FROM DOWNSTATE ILX
ALREADY SHOWING 50+ KTS AT THAT LEVEL...SO LLWS APPEARS A GOOD
BET. WINDS EVENTUALLY SLACK OFF TO 30-40 KTS ABOVE THE INVERSION
DURING THE PRE-DAWN HOURS...AND LLWS SHOULD NOT BE A FACTOR BY
MONDAY MORNING WHEN PRE-FRONTAL TROUGH AND COLD FRONT PUSH
THROUGH.
TROUGH/FRONTAL PASSAGE MONDAY MORNING WILL SHIFT WINDS TO THE
SOUTHWEST INITIALLY...THEN WEST-NORTHWEST BY LATER IN THE MORNING.
COLD ADVECTION AND STEEPENING LOW LEVEL LAPSE RATES WILL ALLOW FOR
MIXING OF HIGHER MOMENTUM AIR TO THE SURFACE...WITH GUSTS IN THE
30-35 KT RANGE BY AFTERNOON. IN ADDITION...ANY LINGERING LIGHT
RAIN WILL CHANGE TO LIGHT SNOW OR SNOW SHOWERS BY MID-MORNING AS
COLUMN COOLS. SOME MINOR ACCUMULATION POSSIBLE...BUT LESS THAN A
HALF INCH EXPECTED.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN CONTINUE LIFR CIGS AND VIS 3/4-1 1/2SM THIS
EVENING. MEDIUM CONFIDENCE IN SOME VIS IMPROVEMENT IN STEADIER
RAIN LATER THIS EVENING/OVERNIGHT.
* LOW CONFIDENCE IN TSRA DIRECTLY IMPACTING ORD/MDW LATE
EVENING...BUT MEDIUM-HIGH CONFIDENCE TSRA WILL OCCUR IN
EAST/SOUTHEAST ARRIVAL/DEPARTURE AIRSPACE ACROSS IN/MI.
* HIGH CONFIDENCE IN LLWS CONDITIONS THIS EVENING.
* HIGH CONFIDENCE IN WIND DIRECTION AND TIMING OF WIND SHIFTS AS
WELL AS WESTERLY WIND GUSTS TO/ABOVE 30 KTS MONDAY AFTERNOON.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...SLIGHT CHANCE OF SNOW SHOWERS LATE...MAINLY VFR.
SATURDAY...VFR.
RATZER
&&
.MARINE...
240 PM CST
DEEP AREA OF LOW PRESSURE WILL LIFT NORTH ACROSS LAKE MICHIGAN
OVERNIGHT WITH STRONG SOUTHERLY WINDS AHEAD OF THE LOW BECOMING
SOUTHWEST AS THE LOW SWEEPS ACROSS THE LAKE. LOW END GALES ARE
POSSIBLE ACROSS CENTRAL PORTIONS OF THE LAKE THROUGH THIS
EVENING...AND WILL ADVECT MOIST DEWPOINTS OVER THE LAKE SETTING UP
THE POTENTIAL FOR DENSE FOG...AS WELL AS THUNDERSTORMS ACROSS THE
SOUTHERN PORTIONS OF THE LAKE. EXPECT A BRIEF LULL IN THE GALES AS
THE PRESSURE GRADIENT BECOMES MORE BAGGY NEAR THE LOW CENTER...
BEFORE STRONGER GALES RESUME MONDAY MORNING. COLD AIR SWEEPING
ACROSS THE LAKE WILL ALLOW FOR DEEP MIXING AND 40 TO 45 KT GALES ARE
EXPECTED...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE LAKE. REPLACED
THE SMALL CRAFT ADVISORY FOR THE NEARSHORE WATERS WITH A GALE WATCH
FOR MONDAY. WINDS BEGIN TO COME DOWN EARLY TUESDAY AS THE LOW LIFTS
AWAY FROM THE GREAT LAKES INTO QUEBEC AND HIGH PRESSURE BEGINS TO
BUILD INTO THE WESTERN GREAT LAKES REGION. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876 UNTIL 9 PM SUNDAY.
GALE WATCH...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...6 AM MONDAY TO 9 AM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 6 AM MONDAY.
GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...6 AM
MONDAY TO 10 PM MONDAY.
DENSE FOG ADVISORY...LMZ080-LMZ777-LMZ779-LMZ878 UNTIL 10 PM
SUNDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ563...NOON MONDAY TO 9 AM
TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1011 AM CST SAT JAN 21 2012
.DISCUSSION...
ISSUED 1011 AM CST SAT JAN 21 2012
DESPITE RIDGE OF HIGH PRESSURE EXTENDING FROM THE NORTHERN GREAT
LAKES INTO THE PLAINS...LOW CLOUDS CONTINUE TO BLANKET NEARLY ALL
OF CENTRAL ILLINOIS THIS MORNING. THE EXCEPTION IS ACROSS THE FAR
NORTHEAST KILX CWA AROUND KCMI AND KDNV...WHERE AN INTRUSION OF DRY
AIR FROM THE NORTHEAST HAS RESULTED IN A LARGE BREAK IN THE
OVERCAST. LOW-LEVEL PROFILERS ARE CURRENTLY SHOWING NORTHEASTERLY
WINDS...HOWEVER THESE WILL VEER MORE EASTERLY THIS AFTERNOON AS
THE HIGH PRESSURE CENTER SHIFTS INTO MICHIGAN. THIS SHOULD PUSH
THE CLEARING SLOWLY WESTWARD AS THE DAY PROGRESSES...WITH MOSTLY
SUNNY SKIES EXPECTED IN THE BLOOMINGTON-NORMAL AND SPRINGFIELD
AREAS BY EARLY AFTERNOON. MEANWHILE...SKIES WILL REMAIN MOSTLY
CLOUDY ALONG AND WEST OF THE ILLINOIS RIVER AND ALONG/SOUTH OF
I-70. DUE TO A NORTHEASTERLY FETCH OFF LAKE MICHIGAN...THE
NORTHWEST KILX CWA MAY EVEN SEE A FEW SNOW FLURRIES FROM TIME TO
TIME. ZONE UPDATE HAS ALREADY BEEN ISSUED.
BARNES
&&
.AVIATION...
ISSUED 556 AM CST SAT JAN 21 2012...FOR THE 12Z TAFS
IFR STRATUS WILL CONTINUE THROUGH MID MORNING...WHEN THE CLOUD
LAYER SHOULD LIFT TO MVFR. PIREPS ARE SHOWING THE CLOUD LAYER AS
ABOUT 2K FT THICK...SO SOME CLEARING MAY DEVELOP AS MIXING DEEPENS
INTO THE DRY LAYER ABOVE 3K FT. THE NORTHWEST EDGE OF THE STRATUS
IS NOT PROGRESSING TO THE ESE AS YOU MIGHT EXPECT BEHIND A LOW
PRESSURE SYSTEM. SO CLEARING IS A TOUGH CALL. RUC AND HRRR MODELS
ARE SHOWING SOME DRYING WORKING INTO OUR AREA FROM THE
NORTHEAST...AS SURFACE WINDS INCREASE FROM THE NORTHEAST. SO CMI
AND DEC MAY BE THE EARLY TERMINAL SITES TO CLEAR OUT TO VFR THIS
AFTERNOON. PIA/BMI/SPI MAY BE DELAYED BY A FEW HOURS TO 20-21Z.
NOT HIGHLY CONFIDENT ON THE CLEARING SCENARIO...BUT WILL INCLUDE
SOME VFR FROM LATE AFTERNOON THROUGH MID EVENING...WHEN MVFR
CLOUDS RETURN ON SOUTHEAST WINDS.
WILL KEEP WINDS IN THE 9-13KT RANGE FOR MOST OF THE NEXT 24
HOURS. SOUTHEAST WIND SPEEDS WILL INCREASE TONIGHT AS THE PRESSURE
GRADIENT TIGHTENS AHEAD OF THE NEXT WEATHER SYSTEM.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 330 AM CST SAT JAN 21 2012
WILL ALLOW THE WINTER WEATHER ADVISORY EXPIRE BY 4 AM SE OF LINCOLN.
MIXED PRECIPITATION HAS PASSED SE OF IL WITH 1008 MB LOW PRESSURE
OVER EASTERN KY. FORECAST CONCERN IS IF ANY CLEARING OCCURS THIS
AFTERNOON. THEN LOOKING AS A FAIRLY STRONG WX SYSTEM TO IMPACT THE
REGION SUNDAY NIGHT WITH SPC HAVE SLIGHT RISK NEAR SOUTHERN PARTS
OF RICHLAND AND LAWRENCE COUNTIES. NCEP FAVORED THE 00Z GFS MODEL
WITH THIS WEATHER SYSTEM WITH ABOVE AVERAGE CONFIDENCE AND WILL
FOLLOW SUITE. LEANED TOWARD THE 00Z ECMWF MODEL WITH MID/LATE WEEK
SYSTEM NEXT WEEK WITH SPLIT UPPER LEVEL FLOW PREVAILING THEN.
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
TRENDED CLOUDIER AND COOLER TODAY WITH FORECAST DUE TO EXTENSIVE
LOW CLOUD COVER ACROSS IL...MO INTO SE HALF OF IA AND LOW LEVEL
MOISTURE TRAPPED IN AN INVERSION. COULD BE A FEW PATCHES OF LIGHT
FREEZING DRIZZLE INTO MID MORNING OVER CENTRAL IL THOUGH HAVE NOT
SCENE ANY REPORTED NEARBY PAST FEW HOURS. TEMPS CURRENTLY RANGE
FROM THE MID TEENS FROM PEORIA NW TO THE MID 20S SE OF I-70. NORTH
WINDS 8 TO 16 MPH. 1027 MB HIGH PRESSURE OVER THE UPPER MS VALLEY
NEAR THE WI/IA/MN BORDER TO DRIFT EAST ACROSS LOWER MI THIS
AFTERNOON AND RIDGING INTO IL. THIS TO DECREASE LOW CLOUDS
OVER NORTHERN AREAS WHERE SKIES BECOME PARTLY SUNNY...WHILE SE IL
STAYS IN THE LOW CLOUDS TODAY. HIGHS MOSTLY IN THE 20S TODAY OVER
CENTRAL IL AND LOWER 30S IN SE IL.
SOUTHERLY FLOW TO SET UP TONIGHT AS HIGH PRESSURE STRENGTHENS TO
1033 MB AS IT MOVES INTO NEW ENGLAND AND MID ATLANTIC STATES BY
DAWN SUNDAY. LOWS PROBABLY REACHED THIS EVENING THEN MAY SNEAK UP
A FEW DEGREES OVERNIGHT AS LOW CLOUDS SPREAD BACK TO THE NORTH. A
FAIRLY STRONG STORM SYSTEM MOVING EAST INTO THE ROCKIES WILL HAVE
A DEEPENING STRONG LOW PRESSURE MOVING INTO THE UPPER MIDWEST
SUNDAY NIGHT AND SWEEP A COLD FRONT EAST THROUGH IL SUNDAY EVENING.
MILDER HIGHS IN THE 40S SUNDAY WITH LOWER 50S IN SE IL. HAVE
SLIGHT CHANCE OF SHOWERS SUNDAY AFTERNOON...EXCEPT 30% CHANCE NW
OF THE IL RIVER. LIKELY CHANCES OF SHOWERS SUNDAY NIGHT AND EVEN
THUNDERSTORMS FROM I-55 EAST SUNDAY EVENING. WILL NEED TO WATCH SE
IL WITH SLIGHT RISK INTO SOUTHERN PARTS OF RICHLAND AND LAWRENCE
COUNTIES SUNDAY EVENING. VERY STRONG UPPER LEVEL DYNAMICS AND WIND
FIELDS AND DEEP MOISTURE WITH STORM. TEMPS COULD RISE A BIT AHEAD
OF THE COLD FRONT SUNDAY EVENING THEN FALL OVERNIGHT INTO MON
MORNING. MODELS HAVE TRENDED FURTHER NE WITH LIGHT MIXED
PRECIPITATION MONDAY WITH 1025 MB HIGH PRESSURE MOVING INTO THE TN
VALLEY BY SUNSET MONDAY AND HAVE ADJUST FORECAST ACCORDINGLY. FAIR
WEATHER EXPECTED MONDAY NIGHT THROUGH TUE NIGHT WITH NEARBY HIGH
PRESSURE.
LONG TERM...WEDNESDAY THROUGH FRIDAY NIGHT
EXTENDED MODELS SHOW A SPLIT UPPER LEVEL FLOW DURING MID AND LATE
WEEK OF NEXT WEEK AND HAVE TRENDED DRIER ON WED. STRONGER SOUTHERN
STREAM SYSTEM WITH CUTOFF LOW OVER NORTHERN MEXICO INTO TX WED-THU
KEEPS MOST OF ITS HEAVIER PRECIP SOUTH CENTRAL IL WHILE WEAKER
NORTHERN STREAM SHORT WAVE MOVES EAST ACROSS THE NORTHERN TIER STATES.
BEST CHANCE OF LIGHT PRECIPITATION APPEARS TO BE OVER SE IL WED
NIGHT AND SHOULD BE WARM ENOUGH FOR RAIN THERE. BEST CHANCES OF
PRECIPITATION APPEARS TO SHIFT EAST OF IL LATE NEXT WEEK AND TRENDED
TOWARD A DRIER FORECAST. GFS AND ECMWF MODEL BOTH HAVE TRENDED
DRIER DURING THIS TIME. TEMPS TO STAY ABOVE NORMAL DURING THIS
TIME FRAME.
HUETTL
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
556 AM CST SAT JAN 21 2012
.DISCUSSION...
ISSUED 330 AM CST SAT JAN 21 2012
WILL ALLOW THE WINTER WEATHER ADVISORY EXPIRE BY 4 AM SE OF LINCOLN.
MIXED PRECIPITATION HAS PASSED SE OF IL WITH 1008 MB LOW PRESSURE
OVER EASTERN KY. FORECAST CONCERN IS IF ANY CLEARING OCCURS THIS
AFTERNOON. THEN LOOKING AS A FAIRLY STRONG WX SYSTEM TO IMPACT THE
REGION SUNDAY NIGHT WITH SPC HAVE SLIGHT RISK NEAR SOUTHERN PARTS
OF RICHLAND AND LAWRENCE COUNTIES. NCEP FAVORED THE 00Z GFS MODEL
WITH THIS WEATHER SYSTEM WITH ABOVE AVERAGE CONFIDENCE AND WILL
FOLLOW SUITE. LEANED TOWARD THE 00Z ECMWF MODEL WITH MID/LATE WEEK
SYSTEM NEXT WEEK WITH SPLIT UPPER LEVEL FLOW PREVAILING THEN.
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
TRENDED CLOUDIER AND COOLER TODAY WITH FORECAST DUE TO EXTENSIVE
LOW CLOUD COVER ACROSS IL...MO INTO SE HALF OF IA AND LOW LEVEL
MOISTURE TRAPPED IN AN INVERSION. COULD BE A FEW PATCHES OF LIGHT
FREEZING DRIZZLE INTO MID MORNING OVER CENTRAL IL THOUGH HAVE NOT
SCENE ANY REPORTED NEARBY PAST FEW HOURS. TEMPS CURRENTLY RANGE
FROM THE MID TEENS FROM PEORIA NW TO THE MID 20S SE OF I-70. NORTH
WINDS 8 TO 16 MPH. 1027 MB HIGH PRESSURE OVER THE UPPER MS VALLEY
NEAR THE WI/IA/MN BORDER TO DRIFT EAST ACROSS LOWER MI THIS
AFTERNOON AND RIDGING INTO IL. THIS TO DECREASE LOW CLOUDS
OVER NORTHERN AREAS WHERE SKIES BECOME PARTLY SUNNY...WHILE SE IL
STAYS IN THE LOW CLOUDS TODAY. HIGHS MOSTLY IN THE 20S TODAY OVER
CENTRAL IL AND LOWER 30S IN SE IL.
SOUTHERLY FLOW TO SET UP TONIGHT AS HIGH PRESSURE STRENGTHENS TO
1033 MB AS IT MOVES INTO NEW ENGLAND AND MID ATLANTIC STATES BY
DAWN SUNDAY. LOWS PROBABLY REACHED THIS EVENING THEN MAY SNEAK UP
A FEW DEGREES OVERNIGHT AS LOW CLOUDS SPREAD BACK TO THE NORTH. A
FAIRLY STRONG STORM SYSTEM MOVING EAST INTO THE ROCKIES WILL HAVE
A DEEPENING STRONG LOW PRESSURE MOVING INTO THE UPPER MIDWEST
SUNDAY NIGHT AND SWEEP A COLD FRONT EAST THROUGH IL SUNDAY EVENING.
MILDER HIGHS IN THE 40S SUNDAY WITH LOWER 50S IN SE IL. HAVE
SLIGHT CHANCE OF SHOWERS SUNDAY AFTERNOON...EXCEPT 30% CHANCE NW
OF THE IL RIVER. LIKELY CHANCES OF SHOWERS SUNDAY NIGHT AND EVEN
THUNDERSTORMS FROM I-55 EAST SUNDAY EVENING. WILL NEED TO WATCH SE
IL WITH SLIGHT RISK INTO SOUTHERN PARTS OF RICHLAND AND LAWRENCE
COUNTIES SUNDAY EVENING. VERY STRONG UPPER LEVEL DYNAMICS AND WIND
FIELDS AND DEEP MOISTURE WITH STORM. TEMPS COULD RISE A BIT AHEAD
OF THE COLD FRONT SUNDAY EVENING THEN FALL OVERNIGHT INTO MON
MORNING. MODELS HAVE TRENDED FURTHER NE WITH LIGHT MIXED
PRECIPITATION MONDAY WITH 1025 MB HIGH PRESSURE MOVING INTO THE TN
VALLEY BY SUNSET MONDAY AND HAVE ADJUST FORECAST ACCORDINGLY. FAIR
WEATHER EXPECTED MONDAY NIGHT THROUGH TUE NIGHT WITH NEARBY HIGH
PRESSURE.
LONG TERM...WEDNESDAY THROUGH FRIDAY NIGHT
EXTENDED MODELS SHOW A SPLIT UPPER LEVEL FLOW DURING MID AND LATE
WEEK OF NEXT WEEK AND HAVE TRENDED DRIER ON WED. STRONGER SOUTHERN
STREAM SYSTEM WITH CUTOFF LOW OVER NORTHERN MEXICO INTO TX WED-THU
KEEPS MOST OF ITS HEAVIER PRECIP SOUTH CENTRAL IL WHILE WEAKER
NORTHERN STREAM SHORT WAVE MOVES EAST ACROSS THE NORTHERN TIER STATES.
BEST CHANCE OF LIGHT PRECIPITATION APPEARS TO BE OVER SE IL WED
NIGHT AND SHOULD BE WARM ENOUGH FOR RAIN THERE. BEST CHANCES OF
PRECIPITATION APPEARS TO SHIFT EAST OF IL LATE NEXT WEEK AND TRENDED
TOWARD A DRIER FORECAST. GFS AND ECMWF MODEL BOTH HAVE TRENDED
DRIER DURING THIS TIME. TEMPS TO STAY ABOVE NORMAL DURING THIS
TIME FRAME.
HUETTL
&&
.AVIATION...
ISSUED 556 AM CST SAT JAN 21 2012...FOR THE 12Z TAFS
IFR STRATUS WILL CONTINUE THROUGH MID MORNING...WHEN THE CLOUD
LAYER SHOULD LIFT TO MVFR. PIREPS ARE SHOWING THE CLOUD LAYER AS
ABOUT 2K FT THICK...SO SOME CLEARING MAY DEVELOP AS MIXING DEEPENS
INTO THE DRY LAYER ABOVE 3K FT. THE NORTHWEST EDGE OF THE STRATUS
IS NOT PROGRESSING TO THE ESE AS YOU MIGHT EXPECT BEHIND A LOW
PRESSURE SYSTEM. SO CLEARING IS A TOUGH CALL. RUC AND HRRR MODELS
ARE SHOWING SOME DRYING WORKING INTO OUR AREA FROM THE
NORTHEAST...AS SURFACE WINDS INCREASE FROM THE NORTHEAST. SO CMI
AND DEC MAY BE THE EARLY TERMINAL SITES TO CLEAR OUT TO VFR THIS
AFTERNOON. PIA/BMI/SPI MAY BE DELAYED BY A FEW HOURS TO 20-21Z.
NOT HIGHLY CONFIDENT ON THE CLEARING SCENARIO...BUT WILL INCLUDE
SOME VFR FROM LATE AFTERNOON THROUGH MID EVENING...WHEN MVFR
CLOUDS RETURN ON SOUTHEAST WINDS.
WILL KEEP WINDS IN THE 9-13KT RANGE FOR MOST OF THE NEXT 24
HOURS. SOUTHEAST WIND SPEEDS WILL INCREASE TONIGHT AS THE PRESSURE
GRADIENT TIGHTENS AHEAD OF THE NEXT WEATHER SYSTEM.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
303 AM CST SAT JAN 21 2012
.DISCUSSION...
910 PM CST
ALL ILLINOIS COUNTIES ARE CLEARED FROM ANY WINTER HEADLINES...WITH
INDIANA TO BE FOLLOWING SUIT SHORTLY. STILL SOME LIGHT SNOW
SHOWERS TO FLURRIES PERSIST FROM ROUGHLY THE I-57 CORRIDOR AND
EAST... BUT OVERALL TRENDS CONTINUE TO DECREASE...AND QUICKLY.
FOCUS ON THE OVERNIGHT WILL THEN TURN TO THE POTENTIAL FOR LAKE
EFFECT SNOWS WITH A CONVERGENT BOUNDARY THAT IS NOTED ON TMKE FROM
EAST OF MILWAUKEE...SOUTHWEST TO ROUGHLY KRAC. HIGH RESOLUTION
GUIDANCE HAS BEEN CONSISTENT IN TAKING THE BOUNDARY AND SWINGING
IT SOUTH...IMPACTING THE COASTAL CITIES. 850 TO LAKE SURFACE DELTA
T/S LOOK SUPPORTIVE FOR A SHORT TIME...AND ALL GUIDANCE KEEPS THE
PRESENT CONVERGENT BOUNDARY AND SUBSEQUENT LES PRESENT INTO THE
AFTERNOON. NO REAL CHANGE TO THE THINKING FROM DAY SHIFT AND WILL
ONLY MAINTAIN THE SLIGHT CHANCE POPS FOR COASTAL LOCATIONS. NOT
EXPECTING MUCH ADDITIONAL SNOWFALL WITH THESE SHOWERS...AND
AMOUNTS LESS THAN AN INCH.
SHEA
//PREV DISCUSSION...
655 PM CST
THE HEAVIEST OF SNOWFALL IS BEGINNING TO SHIFT EAST OF THE AREA
WITH MOST LOCATIONS AT OR ABOVE 1/2 TO 1 MILE VIS. THE EARLIER HEAVY
BANDING LINED UP NICELY WITH AN AREA OF RUC ANALYZED FGEN WITHIN
THE H85 TO H7 LAYER. THAT AREA WILL CONTINUE TO WEAKEN AND SHIFT
EAST - AND NOT EXPECTING ANY FURTHER SIGNIFICANT REDUCTIONS TO
VIS OR INCH PER HOUR SNOWFALL THOUGH THE EVENING. THE BACK EDGE OF
THE PRECIP IS NOTED BASICALLY NOTED FROM WHITEWATER
WISCONSIN...SOUTHWEST THROUGH FREEPORT ILLINOIS. PRESENT WSW GOES
THROUGH 03Z FOR THE NORTHWESTERN TIER OF COUNTIES...AND MAY BEGIN
TO PULL COUNTIES EARLIER AS THE BACK EDGE MOVES THROUGH. FOR
COUNTIES EAST...STILL EXPECT THE SNOWFALL TO DECREASE THROUGH THE
EVENING WITH ONLY MINOR ACCUMULATIONS FOR AREAS WEST OTHE 355/57
CORRIDOR...AND ANOTHER INCH OR SO FOR LOCATIONS ALONG THE
ILLINOIS/INDIANA BORDER AND EAST.
SHEA
.PREVIOUS DISCUSSION...
344 PM CST
NO MAJOR SURPRISES SO FAR...DID EXPAND THE WINTER STORM WARNING INTO
LEE COUNTY THIS AFTERNOON WHICH HAS SEEN PROLONGED PERIOD OF HEAVIER
SNOWFALL WITH DECENT RETURNS STILL UPSTREAM. KENDALL AND WILL
COUNTIES WILL BE CLOSE TO WARNING CRITERIA OF 6" AS AXIS OF MAXIMUM
SNOW SETS UP PRETTY MUCH AS EXPECTED BETWEEN THE I-90 AND I-80
CORRIDORS WITH RATES OF AN INCH AN HOUR...OCCASIONALLY 1.5 INCHES
PER HOUR. EXPECT INTENSITIES TO PEAK ACROSS THE CHICAGO METRO AREA
THROUGH THE EARLY EVENING. DID GET OFF TO A SLOWER START THAN
EXPECTED AND SNOW:LIQUID RATIOS HAVE BEEN A BIT LOWER THAN
ORIGINALLY ANTICIPATED...SO FOR NOW BELIEVE DESPITE THE AXIS SETTING
UP FARTHER SOUTH THAN THE ORIGINAL WARNING AREA...THAT ADVISORY FOR
4 TO 6 INCHES ACROSS KENDALL/WILL COUNTIES AND LAKE COUNTY INDIANA
WILL STAND //THOUGH MAY SEE SOME LOCALIZED AREAS AT OR JUST ABOVE 6
INCHES PARTICULARLY ACROSS FAR NORTHERN WILL COUNTY//. WIDESPREAD
VSBY OF 1/4 MILE OR LESS HAS BEEN REPORTED AND INTERMITTENT
PERIODS OF HEAVY SNOW CONTINUE SO ROADWAYS WILL BE A MESS THROUGH
THE EVENING HOURS.
SATURDAY THROUGH FRIDAY...
SHORT TERM...SATURDAY THROUGH MONDAY...FOLLOWING THE PASSAGE OF THE
MID LEVEL SYSTEM RESPONSIBLE FOR THE SYNOPTIC SNOW...THE INITIAL
FORECAST CONCERN WILL FOCUS ON THE POTENTIAL FOR A LAKE EFFECT BAND
OF SNOW MOVING INTO NERN IL. ALL OF THE GUIDANCE IS INDICATING LAKE
SFC-850MB DELTA-T AROUND 15C OVER SOUTHERN LAKE MICHIGAN...WHICH
WOULD BE CONDUCIVE TO LAKE EFFECT SNOW DEVELOPMENT. THE HIGH RES
WRF-ARW/NMM WITH SUPPORT OF THE OPERATIONAL NAM12...ALL INDICATE A
CONVERGENCE BAND FORMING OVER SOUTHERN LAKE MICHIGAN...WITH THE
POSSIBILITY OF MESOVORTEX DEVELOPMENT WITHIN THE CONVERGENCE ZONE
AND INVERTED TROUGH. WITH TIME...THE BAND SHOULD GRADUALLY MOVE
INLAND AND TO THE NORTHWEST...POSSIBLE AFFECTING PORTIONS OF NERN
AND NCNTRL IL. CONCURRENTLY...LAKE SFC-850MB DELTA T VALUES WILL BE
ON THE DECREASE. SO...EXPECT MORE OF AN ADVECTING BAND OF LAKE
EFFECT SNOW THAN CONTINUOUS PRODUCTION OF LAKE EFFECT SNOW OVER THE
IMMEDIATE LAKE FRONT LOCATIONS. AT THIS TIME...HAVE OPTED TO DEPICT
THIS LAKE EFFECT BAND IN THE GRIDDED FORECAST GRAPHICS WITH AN AREA
OF CHANCE TO SLIGHT CHANCE POPS WITH -SHSN. THERE IS CERTAINLY THE
POTENTIAL FOR ADDITIONAL ACCUMULATING SNOW WITH THE MAIN CONVERGENCE
AREA...BUT DUE TO THE MESOSCALE NATURE OF ANY POSSIBLE MESOVORTEX
DEVELOPMENT...IT IS NOT POSSIBLE TO PINPOINT ANY POSSIBLE HEAVIER
LAKE EFFECT SNOW WITH THIS FEATURE...WHICH WOULD NEED TO BE HANDLED
WITH A NEAR TERM FORECAST UPDATE TOMORROW. ON A LARGER SCALE...HIGH
PRESSURE SHOULD BUILD OVER THE AREA BRINGING DECREASING CLOUD
COVER. TO START OUT SATURDAY MORNING...TEMPERATURES SHOULD RANGE
FROM THE LOWER SINGLE DIGITS OVER THE NWRN PORTIONS OF THE
CWA...WHERE SKIES SHOULD CLEAR THE EARLIEST AND THE GREATEST AMOUNT
OF RADIATING SHOULD OCCUR...TO THE UPPER TEENS ALONG THE LAKE
FRONT...WHERE THERE SHOULD BE THE GREATEST AMOUNT OF RESIDUAL CLOUD
COVER. WITH AT LEAST PARTIAL SUNSHINE AND AN END TO SUSTAINED COLD
ADVECTION OVER THE AREA ON SATURDAY...TEMPERATURES SHOULD SHOULD
REBOUND INTO THE LOWER TO MIDDLE 20S. BY SUNDAY...THE HIGH WILL
MOVE OFF TO THE EAST. A MORE COMPLICATED SITUATION WILL BE SETTING
UP TO THE WEST OF THE LOCAL AREA BY SUNDAY. STRONG NORTHERN AND
SOUTHERN STREAM SHORTWAVES ARE EXPECTED TO EJECT OUT OF THE ROCKIES
BY SUNDAY MORNING...WITH A LARGE AREA OF LOW PRESSURE DEVELOPING
OVER THE CENTRAL PLAINS. THIS WILL INITIATE STRONG WARM/MOIST
ADVECTION INTO THE MIDWEST. THE MODELS ARE INDICATING PHASING OF
THE NORTHERN AND SOUTHERN STREAMS...WITH A CONSOLIDATED SFC LOW
FORMING OVER LOWER MICHIGAN BY MONDAY MORNING. THE MAIN CHANGE TO
THE GOING FORECAST WITH RESPECT TO THIS SYSTEM IS TO SPEED UP THE
PROGRESSION WITH A COLD FRONTAL PASSAGE LATE SUNDAY NIGHT OR EARLY
MONDAY MORNING. WITH THE STRONG WARM ADVECTION...ASSOCIATED PCPN
WILL START OUT IN LIQUID FORM AS TEMPERATURES CLIMB INTO THE UPPER
30S TO LOWER 40S THROUGH THE DAY...WITH TEMPERATURES REMAINING
NEARLY STEADY INTO THE NIGHT. TEMPERATURES WILL NOT DROP OFF UNTIL
AFTER THE FROPA...WHEN TEMPERATURES WILL DROP INTO THE LOWER 20S OVER
THE ROCKFORD AREA. FARTHER SOUTHEAST...SOUTH OF THE KANKAKEE
VALLEY...TEMPS WILL ONLY DROP INTO THE MIDDLE 30S SO A CHANGEOVER
FROM RAIN TO SNOW MAY NOT OCCUR UNTIL LATE IN THE DAY. IT IS EVEN
POSSIBLE THAT TEMPS OVER BENTON/JASPER/NEWTON COUNTY AREA MAY NOT
COOL OFF ENOUGH BEFORE THE SYSTEM LIFTS OUT LATE MONDAY TO EVER SEE
ANY ADDITIONAL SNOW.
EXTENDED FORECAST...TUESDAY THROUGH FRIDAY...CONDITIONS SHOULD QUIET
DOWN CONSIDERABLY THROUGH THE EXTENDED FORECAST PERIOD. BY
TUESDAY...HIGH PRESSURE WILL ONCE AGAIN DOMINATE THE REGION. A
SPLIT FLOW PATTERN IS EXPECTED TO DEVELOP WITH AN ACTIVE NORTHERN
STREAM FOCUSED ALONG THE CANADIAN BORDER WHILE AN ACTIVE SOUTH
STREAM WILL BE FOCUSED ALONG THE RED RIVER VALLEY AND OHIO VALLEY.
IN BETWEEN THESE TWO STREAMS...THE MIDDLE MISSISSIPPI VALLEY AND
MIDWEST WILL REMAIN UNDER A WEAK RIDGE OF HIGH PRESSURE. THE BEST
CHANCE FOR ANY PCPN BETWEEN EARLY TUESDAY AND EARLY FRIDAY WILL BE
ON WEDNESDAY WHEN THE NRN STREAM SYSTEM WILL BE PASSING THROUGH THE
UPPER GREAT LAKES AND STRONG WARM ADVECTION DEVELOPS OVER THE LOWER
AND MIDDLE MISSISSIPPI VALLEY AND SPREADING INTO SOUTHERN IL/IN.
BETWEEN THESE TWO SYSTEM...THERE IS A CHANCE FOR SOME LIGHT RAIN
OVER THE SOUTHERN PORTIONS OF THE CWA...WITH SOME LIGHT SNOW
POSSIBLE OVER THE NRN LOCATIONS. THERE MAY BE A BRIEF TRANSITION
OVER TO ALL LIGHT SNOW WEDNESDAY NIGHT...BEFORE THE NRN STREAM
SYSTEM SCOOTS OFF TO THE EAST. THE NEXT SIGNIFICANT CHANCE FOR PCPN
WILL NOT BE UNTIL LATE IN THE EXTENDED PERIOD...AND WILL BE
ASSOCIATED WITH THE SRN STREAM SYSTEM. THE GFS AND ECMWF ARE IN
DECENT ENOUGH AGREEMENT ON THIS SYSTEM...THOUGH THE ECMWF IS A BIT
FASTER AND HAS A GREATER DEGREE OF PHASING WITH THE NRN STREAM THAN
THE GFS...WHICH INDICATES MORE OF A CUT OFF LOW AND...CONSEQUENTLY...
IS MORE SLOWLY PROGRESSIVE. DEPENDING ON WHETHER THE FASTER OR THE
SLOW SOLUTION VERIFIES...WE COULD SEE PCPN MOVING BACK INTO THE AREA
AS EARLY AS THURSDAY PER THE ECMWF OR FRIDAY PER THE GFS. AT THIS
POINT...HAVE GONE WITH A MORE MIDDLE OF THE ROAD APPROACH FOR THE
LATE EXTENDED PERIOD POPS...WITH SLIGHT CHANCE POPS FOR THURSDAY
NIGHT AND CHANCE POPS FOR FRIDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MVFR CIGS LINGERING THROUGH THE MORNING.
* POTENTIAL FOR LIGHT LAKE EFFECT SNOW SHOWERS AFT 10Z FOR A FEW
HOURS.
* IMPROVEMENT TO VFR EXPECTED THIS AFTERNOON.
* NORTH-NORTHEAST WINDS BECOMING EAST-SOUTHEAST THIS
AFTERNOON.
MDB
//DISCUSSION...UPDATED 09Z...
CONTINUING TO WATCH BAND OF LIGHT LAKE EFFECT SNOW MOVE SOUTHWARD
INTO LAKE COUNTY ILLINOIS. HAVE NOT SEEN MUCH IN THE WAY OF VSBY
REDUCTION SO FAR AND EXPECT ANY REDUCTION TO BE SHORT LIVED.
CONVERGENCE ALONG THE IL SHORE CONTINUES TO PLAY A BIT OF HAVOC
WITH WINDS. SEEING FLUCTUATIONS BETWEEN NORTH AND NORTHEAST WITH
SPEEDS UP AROUND 10 KT THOUGH A FEW GUSTS INTO THE 16-20 KT RANGE
HAVE OCCURRED. THINK THAT WINDOW FOR GUSTS WILL BE CONFINED TO THE
NEXT FEW HOURS BEFORE SPEEDS DIMINISH SLIGHTLY AS HIGH PRESSURE
ARRIVES AND CONVERGENCE ALONG THE LAKE WEAKENS.
MDB
FROM 06Z...
MID-LEVEL DISTURBANCE RESPONSIBLE FOR FRIDAYS SNOW IS MOVING
ACROSS THE FORECAST AREA AT ISSUANCE TIME...WITH SNOW ALREADY
HAVING ENDED RAPIDLY FROM WEST TO EAST ACROSS THE TERMINALS.
PATCHY MVFR CEILINGS REMAIN HOWEVER...GENERALLY IN THE 1200-1800
FOOT RANGE ACROSS NORTHERN IL AT 04Z. A PLACES HAVE SCATTERED OUT
TO VFR BRIEFLY...BUT LOW LEVEL NORTH/NORTHEAST WINDS OFF THE LAKE
AND SOUTHEAST WISCONSIN SHOULD HELP TO MAINTAIN A PREVAILING MVFR
CIG THROUGH THE NIGHT. WITH SNOW ASSOCIATED WITH LARGE SCALE
SYSTEM MOVING OFF TO THE EAST...RADAR IS NOW ABLE TO BETTER DEPICT
WEAK BAND OF LIGHT LAKE EFFECT SNOW WHICH HAS BEEN PERSISTENT
ALONG CONVERGENCE ZONE/TROUGH IN LOW LEVEL WINDS. THIS LIGHT SNOW
IS CURRENTLY AFFECTING MAINLY FAR SOUTHEAST WI FROM MKE SOUTH TO
RAC/ENW...BUT HIGH RES MODELS CONTINUE TO INDICATE THAT THIS WILL
SHIFT SOUTH ACROSS LAKE/COOK COUNTIES LATER TONIGHT AND LINGER
SATURDAY MORNING BEFORE WINDS SHIFT MORE EAST/SOUTHEAST IN THE
AFTERNOON. FORECAST SOUNDINGS DEPICT FAIRLY HEALTHY INVERSION ALOFT
WHICH LOOKS TO PREVENT MUCH IN THE WAY OF DEEP LAKE-INDUCED
CONVECTION FROM DEVELOPING...BUT A PERIOD OF PESKY LIGHT SNOW/SNOW
SHOWERS APPEARS LIKELY DURING THE ROUGHLY 10-15Z PERIOD INTO ORD.
ONCE LOW LEVEL FLOW BECOMES MORE EASTERLY/SOUTHEASTERLY SATURDAY
AFTERNOON...MVFR CIGS SHOULD CONTINUE TO RISE AND SCATTER...WITH
VFR CONDITIONS EXPECTED DURING THE LATE AFTERNOON/EARLY EVENING.
MODELS SUGGEST MVFR CIG AROUND 2500 FT MAY DEVELOP LATER SATURDAY
EVENING AS WARM ADVECTION DEVELOPS AHEAD OF THE NEXT APPROACHING
UPPER TROUGH.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIG TRENDS THROUGH THE MORNING.
* MEDIUM CONFIDENCE IN LAKE EFFECT SNOW SHOWERS...THOUGH LOW
CONFIDENCE IN EXACT PLACEMENT OF NARROW BAND AND DETAILS OF
RELATED CIG/VIS.
* MEDIUM-HIGH CONFIDENCE IN WIND TREND.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF RAIN OR DRIZZLE. MVFR PROBABLE WITH IFR CEILINGS/VIS.
MONDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF RAIN OR SNOW...OTHERWISE VFR.
THURSDAY...SLGT CHANCE OF LGT SNOW...OTHERWISE VFR.
RATZER
&&
.MARINE...
252 AM CST
HIGH PRESSURE WILL SPREAD ACROSS LAKE MICHIGAN TODAY BUT THE WEAK
LARGER SCALE FLOW WILL CONTINUE TO SUPPORT LAKE INFLUENCED
WINDS...ESPECIALLY ACROSS THE SOUTHERN PART OF THE LAKE. AN
AREA OF CONVERGENCE CONTINUES TO MOVE DOWN THE WESTERN SHORE
TOWARD THE IL/WI BORDER WITH NORTHWEST WINDS TO THE WEST AND EAST
TO NORTHEAST WINDS TO THE EAST OF THIS BOUNDARY. SPEEDS ARE
GENERALLY IN THE 10-20 KT RANGE WITH A FEW GUSTS TO 25 KT POSSIBLE BUT
SHOULD FALL OFF AS THE CONVERGENCE WEAKENS THROUGH LATE
MORNING/EARLY AFTERNOON. OTHERWISE WINDS WILL BECOME VARIABLE
ACROSS MUCH OF THE LAKE THIS AFTERNOON AS THE HIGH ARRIVES. WINDS
WILL THEN TURN SOUTHERLY INTO THIS EVENING WITH SPEEDS STEADILY
PICKING UP FROM SOUTH TO NORTH. IT APPEARS THAT LOW END GALES WILL
BE POSSIBLE LATE TONIGHT AND CONTINUE THROUGH MUCH OF SUNDAY.
SURFACE LOW PRESSURE NOW BUILDING INTO THE HIGH PLAINS WILL
CONSOLIDATE TO THE WEST OR SOUTHWEST AND THEN MOVE NORTH-
NORTHEASTWARD UP LAKE MICHIGAN SUNDAY NIGHT AND MONDAY MORNING.
THIS MAY RESULT IN A BRIEF EASING OF THE WINDS SUNDAY EVENING BUT
THIS TIMING IS SUBJECT TO CHANGE BASED ON THE SPEED OF THE LOW.
WINDS WILL THEN SHIFT TO THE SOUTHWEST AND WEST MONDAY WITH GALES
RETURNING...ESPECIALLY SOUTH...THAT IS IF SPEEDS EASE BELOW GALES
AS THE LOW MOVES OVER THE LAKE. WILL KEEP THE GALE WATCH GOING
THROUGH SUNDAY EVENING BUT IT MAY NEED TO BE EXTENDED RIGHT
THROUGH MONDAY AND MONDAY NIGHT. HIGH PRESSURE WILL BUILD BACK
ACROSS THE LAKE TUESDAY ALLOWING WINDS TO DIMINISH. THE REST OF
THE WEEK LOOKS ACTIVE WITH A SERIES OF LOWS EXPECTED TO PASS NORTH
OF THE LAKE RESULTING IN PERIODIC WIND SHIFTS AS EACH ASSOCIATED
TROUGH AXIS PASSES WITH AN INCREASE IN WINDS SPEED AS THIS OCCURS
AS WELL. TOO EARLY TO TELL IF SHORT PERIODS OF GALES WILL
MATERIALIZE BUT IT IS A POSSIBILITY.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SUNDAY TO 9 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1048 PM CST FRI JAN 20 2012
.DISCUSSION...
910 PM CST
ALL ILLINOIS COUNTIES ARE CLEARED FROM ANY WINTER HEADLINES...WITH
INDIANA TO BE FOLLOWING SUIT SHORTLY. STILL SOME LIGHT SNOW
SHOWERS TO FLURRIES PERSIST FROM ROUGHLY THE I-57 CORRIDOR AND
EAST... BUT OVERALL TRENDS CONTINUE TO DECREASE...AND QUICKLY.
FOCUS ON THE OVERNIGHT WILL THEN TURN TO THE POTENTIAL FOR LAKE
EFFECT SNOWS WITH A CONVERGENT BOUNDARY THAT IS NOTED ON TMKE FROM
EAST OF MILWAUKEE...SOUTHWEST TO ROUGHLY KRAC. HIGH RESOLUTION
GUIDANCE HAS BEEN CONSISTENT IN TAKING THE BOUNDARY AND SWINGING
IT SOUTH...IMPACTING THE COASTAL CITIES. 850 TO LAKE SURFACE DELTA
T/S LOOK SUPPORTIVE FOR A SHORT TIME...AND ALL GUIDANCE KEEPS THE
PRESENT CONVERGENT BOUNDARY AND SUBSEQUENT LES PRESENT INTO THE
AFTERNOON. NO REAL CHANGE TO THE THINKING FROM DAY SHIFT AND WILL
ONLY MAINTAIN THE SLIGHT CHANCE POPS FOR COASTAL LOCATIONS. NOT
EXPECTING MUCH ADDITIONAL SNOWFALL WITH THESE SHOWERS...AND
AMOUNTS LESS THAN AN INCH.
SHEA
//PREV DISCUSSION...
655 PM CST
THE HEAVIEST OF SNOWFALL IS BEGINNING TO SHIFT EAST OF THE AREA
WITH MOST LOCATIONS AT OR ABOVE 1/2 TO 1 MILE VIS. THE EARLIER HEAVY
BANDING LINED UP NICELY WITH AN AREA OF RUC ANALYZED FGEN WITHIN
THE H85 TO H7 LAYER. THAT AREA WILL CONTINUE TO WEAKEN AND SHIFT
EAST - AND NOT EXPECTING ANY FURTHER SIGNIFICANT REDUCTIONS TO
VIS OR INCH PER HOUR SNOWFALL THOUGH THE EVENING. THE BACK EDGE OF
THE PRECIP IS NOTED BASICALLY NOTED FROM WHITEWATER
WISCONSIN...SOUTHWEST THROUGH FREEPORT ILLINOIS. PRESENT WSW GOES
THROUGH 03Z FOR THE NORTHWESTERN TIER OF COUNTIES...AND MAY BEGIN
TO PULL COUNTIES EARLIER AS THE BACK EDGE MOVES THROUGH. FOR
COUNTIES EAST...STILL EXPECT THE SNOWFALL TO DECREASE THROUGH THE
EVENING WITH ONLY MINOR ACCUMULATIONS FOR AREAS WEST OTHE 355/57
CORRIDOR...AND ANOTHER INCH OR SO FOR LOCATIONS ALONG THE
ILLINOIS/INDIANA BORDER AND EAST.
SHEA
.PREVIOUS DISCUSSION...
344 PM CST
NO MAJOR SURPRISES SO FAR...DID EXPAND THE WINTER STORM WARNING INTO
LEE COUNTY THIS AFTERNOON WHICH HAS SEEN PROLONGED PERIOD OF HEAVIER
SNOWFALL WITH DECENT RETURNS STILL UPSTREAM. KENDALL AND WILL
COUNTIES WILL BE CLOSE TO WARNING CRITERIA OF 6" AS AXIS OF MAXIMUM
SNOW SETS UP PRETTY MUCH AS EXPECTED BETWEEN THE I-90 AND I-80
CORRIDORS WITH RATES OF AN INCH AN HOUR...OCCASIONALLY 1.5 INCHES
PER HOUR. EXPECT INTENSITIES TO PEAK ACROSS THE CHICAGO METRO AREA
THROUGH THE EARLY EVENING. DID GET OFF TO A SLOWER START THAN
EXPECTED AND SNOW:LIQUID RATIOS HAVE BEEN A BIT LOWER THAN
ORIGINALLY ANTICIPATED...SO FOR NOW BELIEVE DESPITE THE AXIS SETTING
UP FARTHER SOUTH THAN THE ORIGINAL WARNING AREA...THAT ADVISORY FOR
4 TO 6 INCHES ACROSS KENDALL/WILL COUNTIES AND LAKE COUNTY INDIANA
WILL STAND //THOUGH MAY SEE SOME LOCALIZED AREAS AT OR JUST ABOVE 6
INCHES PARTICULARLY ACROSS FAR NORTHERN WILL COUNTY//. WIDESPREAD
VSBY OF 1/4 MILE OR LESS HAS BEEN REPORTED AND INTERMITTENT
PERIODS OF HEAVY SNOW CONTINUE SO ROADWAYS WILL BE A MESS THROUGH
THE EVENING HOURS.
SATURDAY THROUGH FRIDAY...
SHORT TERM...SATURDAY THROUGH MONDAY...FOLLOWING THE PASSAGE OF THE
MID LEVEL SYSTEM RESPONSIBLE FOR THE SYNOPTIC SNOW...THE INITIAL
FORECAST CONCERN WILL FOCUS ON THE POTENTIAL FOR A LAKE EFFECT BAND
OF SNOW MOVING INTO NERN IL. ALL OF THE GUIDANCE IS INDICATING LAKE
SFC-850MB DELTA-T AROUND 15C OVER SOUTHERN LAKE MICHIGAN...WHICH
WOULD BE CONDUCIVE TO LAKE EFFECT SNOW DEVELOPMENT. THE HIGH RES
WRF-ARW/NMM WITH SUPPORT OF THE OPERATIONAL NAM12...ALL INDICATE A
CONVERGENCE BAND FORMING OVER SOUTHERN LAKE MICHIGAN...WITH THE
POSSIBILITY OF MESOVORTEX DEVELOPMENT WITHIN THE CONVERGENCE ZONE
AND INVERTED TROUGH. WITH TIME...THE BAND SHOULD GRADUALLY MOVE
INLAND AND TO THE NORTHWEST...POSSIBLE AFFECTING PORTIONS OF NERN
AND NCNTRL IL. CONCURRENTLY...LAKE SFC-850MB DELTA T VALUES WILL BE
ON THE DECREASE. SO...EXPECT MORE OF AN ADVECTING BAND OF LAKE
EFFECT SNOW THAN CONTINUOUS PRODUCTION OF LAKE EFFECT SNOW OVER THE
IMMEDIATE LAKE FRONT LOCATIONS. AT THIS TIME...HAVE OPTED TO DEPICT
THIS LAKE EFFECT BAND IN THE GRIDDED FORECAST GRAPHICS WITH AN AREA
OF CHANCE TO SLIGHT CHANCE POPS WITH -SHSN. THERE IS CERTAINLY THE
POTENTIAL FOR ADDITIONAL ACCUMULATING SNOW WITH THE MAIN CONVERGENCE
AREA...BUT DUE TO THE MESOSCALE NATURE OF ANY POSSIBLE MESOVORTEX
DEVELOPMENT...IT IS NOT POSSIBLE TO PINPOINT ANY POSSIBLE HEAVIER
LAKE EFFECT SNOW WITH THIS FEATURE...WHICH WOULD NEED TO BE HANDLED
WITH A NEAR TERM FORECAST UPDATE TOMORROW. ON A LARGER SCALE...HIGH
PRESSURE SHOULD BUILD OVER THE AREA BRINGING DECREASING CLOUD
COVER. TO START OUT SATURDAY MORNING...TEMPERATURES SHOULD RANGE
FROM THE LOWER SINGLE DIGITS OVER THE NWRN PORTIONS OF THE
CWA...WHERE SKIES SHOULD CLEAR THE EARLIEST AND THE GREATEST AMOUNT
OF RADIATING SHOULD OCCUR...TO THE UPPER TEENS ALONG THE LAKE
FRONT...WHERE THERE SHOULD BE THE GREATEST AMOUNT OF RESIDUAL CLOUD
COVER. WITH AT LEAST PARTIAL SUNSHINE AND AN END TO SUSTAINED COLD
ADVECTION OVER THE AREA ON SATURDAY...TEMPERATURES SHOULD SHOULD
REBOUND INTO THE LOWER TO MIDDLE 20S. BY SUNDAY...THE HIGH WILL
MOVE OFF TO THE EAST. A MORE COMPLICATED SITUATION WILL BE SETTING
UP TO THE WEST OF THE LOCAL AREA BY SUNDAY. STRONG NORTHERN AND
SOUTHERN STREAM SHORTWAVES ARE EXPECTED TO EJECT OUT OF THE ROCKIES
BY SUNDAY MORNING...WITH A LARGE AREA OF LOW PRESSURE DEVELOPING
OVER THE CENTRAL PLAINS. THIS WILL INITIATE STRONG WARM/MOIST
ADVECTION INTO THE MIDWEST. THE MODELS ARE INDICATING PHASING OF
THE NORTHERN AND SOUTHERN STREAMS...WITH A CONSOLIDATED SFC LOW
FORMING OVER LOWER MICHIGAN BY MONDAY MORNING. THE MAIN CHANGE TO
THE GOING FORECAST WITH RESPECT TO THIS SYSTEM IS TO SPEED UP THE
PROGRESSION WITH A COLD FRONTAL PASSAGE LATE SUNDAY NIGHT OR EARLY
MONDAY MORNING. WITH THE STRONG WARM ADVECTION...ASSOCIATED PCPN
WILL START OUT IN LIQUID FORM AS TEMPERATURES CLIMB INTO THE UPPER
30S TO LOWER 40S THROUGH THE DAY...WITH TEMPERATURES REMAINING
NEARLY STEADY INTO THE NIGHT. TEMPERATURES WILL NOT DROP OFF UNTIL
AFTER THE FROPA...WHEN TEMPERATURES WILL DROP INTO THE LOWER 20S OVER
THE ROCKFORD AREA. FARTHER SOUTHEAST...SOUTH OF THE KANKAKEE
VALLEY...TEMPS WILL ONLY DROP INTO THE MIDDLE 30S SO A CHANGEOVER
FROM RAIN TO SNOW MAY NOT OCCUR UNTIL LATE IN THE DAY. IT IS EVEN
POSSIBLE THAT TEMPS OVER BENTON/JASPER/NEWTON COUNTY AREA MAY NOT
COOL OFF ENOUGH BEFORE THE SYSTEM LIFTS OUT LATE MONDAY TO EVER SEE
ANY ADDITIONAL SNOW.
EXTENDED FORECAST...TUESDAY THROUGH FRIDAY...CONDITIONS SHOULD QUIET
DOWN CONSIDERABLY THROUGH THE EXTENDED FORECAST PERIOD. BY
TUESDAY...HIGH PRESSURE WILL ONCE AGAIN DOMINATE THE REGION. A
SPLIT FLOW PATTERN IS EXPECTED TO DEVELOP WITH AN ACTIVE NORTHERN
STREAM FOCUSED ALONG THE CANADIAN BORDER WHILE AN ACTIVE SOUTH
STREAM WILL BE FOCUSED ALONG THE RED RIVER VALLEY AND OHIO VALLEY.
IN BETWEEN THESE TWO STREAMS...THE MIDDLE MISSISSIPPI VALLEY AND
MIDWEST WILL REMAIN UNDER A WEAK RIDGE OF HIGH PRESSURE. THE BEST
CHANCE FOR ANY PCPN BETWEEN EARLY TUESDAY AND EARLY FRIDAY WILL BE
ON WEDNESDAY WHEN THE NRN STREAM SYSTEM WILL BE PASSING THROUGH THE
UPPER GREAT LAKES AND STRONG WARM ADVECTION DEVELOPS OVER THE LOWER
AND MIDDLE MISSISSIPPI VALLEY AND SPREADING INTO SOUTHERN IL/IN.
BETWEEN THESE TWO SYSTEM...THERE IS A CHANCE FOR SOME LIGHT RAIN
OVER THE SOUTHERN PORTIONS OF THE CWA...WITH SOME LIGHT SNOW
POSSIBLE OVER THE NRN LOCATIONS. THERE MAY BE A BRIEF TRANSITION
OVER TO ALL LIGHT SNOW WEDNESDAY NIGHT...BEFORE THE NRN STREAM
SYSTEM SCOOTS OFF TO THE EAST. THE NEXT SIGNIFICANT CHANCE FOR PCPN
WILL NOT BE UNTIL LATE IN THE EXTENDED PERIOD...AND WILL BE
ASSOCIATED WITH THE SRN STREAM SYSTEM. THE GFS AND ECMWF ARE IN
DECENT ENOUGH AGREEMENT ON THIS SYSTEM...THOUGH THE ECMWF IS A BIT
FASTER AND HAS A GREATER DEGREE OF PHASING WITH THE NRN STREAM THAN
THE GFS...WHICH INDICATES MORE OF A CUT OFF LOW AND...CONSEQUENTLY...
IS MORE SLOWLY PROGRESSIVE. DEPENDING ON WHETHER THE FASTER OR THE
SLOW SOLUTION VERIFIES...WE COULD SEE PCPN MOVING BACK INTO THE AREA
AS EARLY AS THURSDAY PER THE ECMWF OR FRIDAY PER THE GFS. AT THIS
POINT...HAVE GONE WITH A MORE MIDDLE OF THE ROAD APPROACH FOR THE
LATE EXTENDED PERIOD POPS...WITH SLIGHT CHANCE POPS FOR THURSDAY
NIGHT AND CHANCE POPS FOR FRIDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS LINGERING OVERNIGHT AND SATURDAY MORNING.
* POTENTIAL FOR LIGHT LAKE EFFECT SNOW SHOWERS TOWARD MORNING.
* IMPROVEMENT TO VFR EXPECTED SATURDAY AFTERNOON.
* NORTH-NORTHEAST WINDS BECOMING EAST-SOUTHEAST SATURDAY
AFTERNOON.
RATZER
//DISCUSSION...UPDATED 06Z...
MID-LEVEL DISTURBANCE RESPONSIBLE FOR FRIDAYS SNOW IS MOVING
ACROSS THE FORECAST AREA AT ISSUANCE TIME...WITH SNOW ALREADY
HAVING ENDED RAPIDLY FROM WEST TO EAST ACROSS THE TERMINALS.
PATCHY MVFR CEILINGS REMAIN HOWEVER...GENERALLY IN THE 1200-1800
FOOT RANGE ACROSS NORTHERN IL AT 04Z. A PLACES HAVE SCATTERED OUT
TO VFR BRIEFLY...BUT LOW LEVEL NORTH/NORTHEAST WINDS OFF THE LAKE
AND SOUTHEAST WISCONSIN SHOULD HELP TO MAINTAIN A PREVAILING MVFR
CIG THROUGH THE NIGHT. WITH SNOW ASSOCIATED WITH LARGE SCALE
SYSTEM MOVING OFF TO THE EAST...RADAR IS NOW ABLE TO BETTER DEPICT
WEAK BAND OF LIGHT LAKE EFFECT SNOW WHICH HAS BEEN PERSISTENT
ALONG CONVERGENCE ZONE/TROUGH IN LOW LEVEL WINDS. THIS LIGHT SNOW
IS CURRENTLY AFFECTING MAINLY FAR SOUTHEAST WI FROM MKE SOUTH TO
RAC/ENW...BUT HIGH RES MODELS CONTINUE TO INDICATE THAT THIS WILL
SHIFT SOUTH ACROSS LAKE/COOK COUNTIES LATER TONIGHT AND LINGER
SATURDAY MORNING BEFORE WINDS SHIFT MORE EAST/SOUTHEAST IN THE
AFTERNOON. FORECAST SOUNDINGS DEPICT FAIRLY HEALTHY INVERSION ALOFT
WHICH LOOKS TO PREVENT MUCH IN THE WAY OF DEEP LAKE-INDUCED
CONVECTION FROM DEVELOPING...BUT A PERIOD OF PESKY LIGHT SNOW/SNOW
SHOWERS APPEARS LIKELY DURING THE ROUGHLY 10-15Z PERIOD INTO ORD.
ONCE LOW LEVEL FLOW BECOMES MORE EASTERLY/SOUTHEASTERLY SATURDAY
AFTERNOON...MVFR CIGS SHOULD CONTINUE TO RISE AND SCATTER...WITH
VFR CONDITIONS EXPECTED DURING THE LATE AFTERNOON/EARLY EVENING.
MODELS SUGGEST MVFR CIG AROUND 2500 FT MAY DEVELOP LATER SATURDAY
EVENING AS WARM ADVECTION DEVELOPS AHEAD OF THE NEXT APPROACHING
UPPER TROUGH.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIG TRENDS THROUGH SATURDAY
MORNING.
* MEDIUM CONFIDENCE IN LAKE EFFECT SNOW SHOWERS...THOUGH LOW
CONFIDENCE IN EXACT PLACEMENT OF NARROW BAND AND DETAILS OF
RELATED CIG/VIS.
* MEDIUM-HIGH CONFIDENCE IN WIND TREND.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF RAIN OR DRIZZLE. MVFR PROBABLE WITH IFR CEILINGS/VIS.
MONDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF RAIN OR SNOW...OTHERWISE VFR.
THURSDAY...SLGT CHANCE OF LGT SNOW...OTHERWISE VFR.
RATZER
&&
.MARINE...
316 PM CST
TWO LOW PRESSURE SYSTEMS...ONE OVER ONTARIO AND ONE IN THE OHIO
VALLEY...WILL FIGHT FOR INFLUENCE OVER THE LAKE THIS EVENING. THIS
WILL RESULT IN VARIABLE WINDS FOR A WHILE...WHICH EVENTUALLY TURN
NORTHWEST OVER THE NORTH HALF AND NORTHEAST OVER THE SOUTH AHEAD
OF AN APPROACHING CENTER OF HIGH PRESSURE. WINDS GO LIGHT AND
VARIABLE AS THE HIGH PRESSURE MOVES ACROSS THE LAKE TOMORROW. BY
SUNDAY A NEW LOW PRESSURE SYSTEM AND TRAILING COLD FRONT APPROACH
FROM THE WEST.
DECISION TO POST A GALE WATCH FOR SUNDAY WAS BASED ON EXPECTATION
OF STRONG SOUTH WINDS AHEAD OF THE FRONT...GUSTING INTO THE 35 KT
RANGE. ACTUALLY FEEL STRONGER WINDS WILL ARRIVE MONDAY AFTER THE
FRONT PASSES AND WINDS TURN WEST. THESE ALSO WILL HAVE THE
ADVANTAGE OF BEING COLDER AND IN A MORE WELL MIXED AIRMASS...THUS
SUPPORTING BETTER MIXING OF GUSTS TO THE LAKE SURFACE. AT THIS
POINT THE REST OF NEXT WEEK LOOKS RELATIVELY QUIET...FOR NOW.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SUNDAY TO 9 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
927 PM EST SUN JAN 22 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT AND
MONDAY...BRINGING POTENTIALLY SEVERE THUNDERSTORMS...STRONG
WINDS...AND HEAVY RAIN. MUCH COLDER AIR WILL FLOW IN BEHIND THE
FRONT. DRY WEATHER WILL THEN CONTINUE UNTIL MID TO LATE WEEK WHEN A
COUPLE OF SYSTEMS COULD BRING SOME LIGHT PRECIPITATION.
&&
.NEAR TERM /TONIGHT/...
LOTS OF ISSUES TO DEAL WITH IN THE NEAR TERM. MOST POTENT WILL BE
THE POTENTIAL FOR SEVERE CONVECTIVE WEATHER OVERNIGHT AHEAD OF
STRONG COLD FRONT.
ALTHOUGH WARM AIR IS SLOW IN COMING...LOOKING UPSTREAM SOME OF IT
SHOULD STILL GET HERE IN TIME FOR THE FORCING AHEAD OF THE FRONT.
TEMPERATURES MAY NOT BE QUITE AS WARM AS MODEL SHOWS...ESPECIALLY
NORTH WHERE THE SNOW COVER IS. BEST INSTABILITY WILL BE ALOFT
ANYWAY. ALTHOUGH EVEN THAT INSTABILITY WILL BE RELATIVELY
WEAK...THE VERY STRONG WINDS ALOFT WILL CREATE STRONG SHEAR.
850MB WINDS WILL BE UP TO 6 STANDARD DEVIATIONS ABOVE AVERAGE. EVEN
925MB WINDS WILL BE OVER 50KT...WITH GFS SHOWING 60-70KT IN
SOUTHWEST INDIANA. THUS THE SHEAR PLUS THE STRONG LIFT SHOULD
OVERCOME THE LACK OF INSTABILITY FOR STRONG THUNDERSTORMS...ESPECIALLY
ACROSS THE SOUTHERN FORECAST AREA WHERE BEST SHEAR WILL BE.
THE STORMS WILL HAVE TO PUSH THROUGH A DECENT INVERSION TO GET THE
DAMAGING WINDS TO THE SURFACE. THIS WILL AGAIN WILL BE EASIEST
ACROSS THE SOUTHERN FORECAST AREA WHERE TEMPERATURES WILL BE WARMER.
KEEP IN MIND THIS INVERSION HAS THE POTENTIAL TO LIMIT THE SEVERE
WEATHER IF IT IS STRONG ENOUGH. HOWEVER EVEN IF THE WINDS THAT
MAKE IT TO THE SURFACE ARE NON SEVERE...THE WET GROUND MAY ALLOW
TREES TO FALL DOWN EASIER.
THUS WILL MENTION SEVERE STORMS IN THE FORECAST. CURRENT TIMING
LOOKS TO BE 05-10Z. PRIMARY THREAT WILL BE THE DAMAGING WINDS...BUT
WITH THE STRONG SHEAR CANNOT RULE OUT TORNADOES.
THE OTHER PROBLEM WILL BE FLOODING POTENTIAL. EVEN A HALF INCH OF
RAIN MAY CAUSE AREAL FLOODING...AND THIS LINE DEFINITELY HAS THE
POTENTIAL TO DROP A HALF INCH. WILL CONTINUE TO MENTION FLOODING
POTENTIAL IN HWO.
TEMPERATURE FORECAST WILL BE TRICKY...WITH THE SLOW MOVEMENT OF THE
WARM AIR NORTH THIS AFTERNOON. WILL USE RUC AS A PART OF THE FIRST
GUESS AS LOW TEMPERATURES SHOULD OCCUR AT 00Z. READINGS WILL RISE
OVERNIGHT AND PERHAPS BEGIN TO FALL LATE TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
FOCUS IS ON WINDS ON MONDAY. MODELS ARE SIMILAR ENOUGH SO THAT A
BLEND CAN BE USED FOR THE MOST PART.
ACTUAL COLD FRONT WILL PASS ACROSS THE AREA EARLY ON MONDAY. STRONG
WINDS COULD STILL MIX DOWN WITH ANY SHOWERS THAT DEVELOP ALONG THIS
FRONT. ALSO...WITH STRONG PRESSURE RISES BEHIND THE FRONT...THERE
WILL BE GUSTY WINDS THROUGHOUT THE DAY. BUFKIT SHOWS GUSTS NEAR 45
MPH POSSIBLE...ESPECIALLY ACROSS THE NORTHERN FORECAST AREA.
THUS WILL ISSUE A WIND ADVISORY ON MONDAY FOR 12Z-22Z. FAR SOUTHERN
FORECAST AREA IS MORE BORDERLINE...BUT WOULD RATHER BE
PESSIMISTIC...ESPECIALLY WITH POTENTIAL GUSTS ALONG FRONT ITSELF.
THERE LOOKS TO BE ENOUGH FORCING ALONG THE FRONT AND EVEN BEHIND IT
FOR A CHANCE FOR SHOWERS MONDAY MORNING. DURING THE AFTERNOON
MOISTURE AND FORCING ARE LIMITED. BY AFTERNOON ALSO TEMPERATURES
WILL BE COLD ENOUGH FOR SOME SNOW AS WELL. THUS WILL GO WITH
SPRINKLES OR FLURRIES MONDAY AFTERNOON.
TEMPERATURES WILL FALL ON MONDAY WITH HIGHS AT 12Z JUST AHEAD OF THE
FRONT.
DRY WEATHER WILL THEN MOVE IN MONDAY NIGHT INTO TUESDAY NIGHT WITH
HIGH PRESSURE MOVING IN. A BLEND OF MOS LOOKS OK FOR TEMPERATURES.
A SOUTHERN SYSTEM WILL MOVE NORTH ON WEDNESDAY WITH RAIN TRYING TO
WORK INTO THE AREA. THE MOISTURE WILL HAVE TO DISPLACE DRIER AIR
ASSOCIATED WITH HIGH PRESSURE TO THE NORTH. FOR NOW WILL JUST PUT
SLIGHT CHANCES FOR RAIN ACROSS THE FAR SOUTH DURING THE AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE MAIN CONCERN IN THE EXTENDED WILL BE POPS WEDNESDAY NIGHT AND
THURSDAY AS WELL AS FRIDAY NIGHT AS SEPARATE SYSTEMS IMPACT CENTRAL
INDIANA.
ALTHOUGH THE MODELS HAVE SOME TIMING ISSUES AS WELL AS ISSUES ABOUT
HOW FAR NORTH THE PRECIPITATION SHIELD WILL MAKE IT WEDNESDAY NIGHT
AND THURSDAY. BASIC SCENARIO HAS MOIST AIR RETURNING NORTHWARD FROM
THE GULF OF MEXICO OVERTOP A SOUTHERN WARM FRONT AND BEING LIFTED BY
A COLD FRONT APPROACHING FROM THE NORTHERN PLAINS. CENTRAL REGION
INITIALIZATION SEEMS TO HANDLE THINGS OK BRINGING CHANCE POPS TO ALL
OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY SIDING MORE WITH THE
00Z AND 12Z ECMWF. WENT WITH A MIX WEDNESDAY NIGHT AND THURSDAY
MORNING AS TEMPERATURES LOOK TO BOTTOM OUT IN THE UPPER 20S AND
LOWER 30S. WILL ONLY GO WITH RAIN ON THURSDAY AFTERNOON WITH
TEMPERATURES IN THE 40S.
LOOKS LIKE ANOTHER CHANCE FOR A RAIN AND SNOW MIX FRIDAY NIGHT AS
ANOTHER COLD FRONT DROPS DOWN FROM THE NORTHWEST. OTHERWISE...HIGH
PRESSURE SHOULD KEEP IT DRY. JET STREAM FLOW OFF THE PACIFIC
SUGGESTS WARMER THAN NORMAL TEMPERATURES THROUGH FRIDAY BUT BECOMING
MORE NEAR NORMAL STARTING SATURDAY AS INTERIOR CANADIAN WAVE DROPS
DOWN ACROSS THE LOWER GREAT LAKES.
&&
.AVIATION /DISCUSSION FOR THE 23/09Z TAF UPDATE/...
UPDATE...
WINDS HAVE INCREASED AND WARMER AIR IS CURRENTLY FILTERING INTO
KIND. TEMPERATURE INVERSION HAS DECREASED A TAD...AND VISIBILITIES
HAVE IMPROVED. NONETHELESS...CEILINGS REMAIN AT VLIFR CATEGORY AND
WILL PROBABLY ONLY IMPROVE TO LIFR IF AT ALL BEFORE THE COLD FRONT
MOVES THROUGH. SEE BELOW.
PREVIOUS DISCUSSION...
VLIFR/LIFR WILL CONTINUE UNTIL THE PERSISTENT TEMPERATURE
INVERSION BREAKS...WHICH WILL NOT BE UNTIL AFTER FRONTAL PASSAGE
LATER TONIGHT. A LINE OF STRONG TO SEVERE THUNDERSTORMS IS
EXPECTED WITH THAT COLD FRONT...AND SHOULD START ENTERING TAF
SITES AROUND MON 06Z. THE BULK OF THE CONVECTION WILL BE IN THE
MON 06-12Z TIME FRAME. AFTER THAT...VISIBILITIES SHOULD IMPROVE
SIGNIFICANTLY...AND TAFS SHOULD RETURN TO MVFR CATEGORY.
THERE IS STILL CONCERN IN REGARD TO WIND SHEAR AHEAD OF THE
AFOREMENTIONED FRONT. WINDS WILL STILL BE LIGHT AT THE
SURFACE...BUT A LOW LEVEL JET WILL INCREASE WINDS UNDER THE
INVERSION. UNTIL THE INVERSION BREAKS AND WINDS CAN MIX
DOWN...WIND SHEAR WILL REMAIN A THREAT.
THE SHEAR THREAT WILL DIMINISH AFTER MON 06Z...BUT SURFACE WINDS
WILL REMAIN STRONG AND SLOWLY VEER TO THE SOUTHWEST. SUSTAINED WIND
SPEEDS WILL RANGE FROM 15 TO 25 KTS WITH GUSTS UP TO 35 KTS
THROUGH TOMORROW AFTERNOON. THEY WILL FINALLY RELAX BY LATE
AFTERNOON AND BECOME MORE WESTERLY.
AT THIS TIME...WANTED TO BUMP CONDITIONS UP TO VFR CATEGORY BY
TOMORROW EVENING...BUT THAT MAY STILL BE A BIT TOO OPTIMISTIC AT
THIS POINT. AS A RESULT...WILL KEEP THEM AT MVFR THROUGH END OF
TAF PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 7 AM TO 5 PM EST MONDAY FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
754 PM EST SUN JAN 22 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT AND
MONDAY...BRINGING POTENTIALLY SEVERE THUNDERSTORMS...STRONG
WINDS...AND HEAVY RAIN. MUCH COLDER AIR WILL FLOW IN BEHIND THE
FRONT. DRY WEATHER WILL THEN CONTINUE UNTIL MID TO LATE WEEK WHEN A
COUPLE OF SYSTEMS COULD BRING SOME LIGHT PRECIPITATION.
&&
.MESOSCALE UPDATE...
WARM MOIST AIRMASS SURGING INTO THE REGION THIS EVENING COURTESY
OF INTENSIFYING LOW LEVEL JET EXPANDING INTO THE OHIO VALLEY
AHEAD OF DEEPENING LOW PRESSURE CURRENTLY NEAR KANSAS CITY. MUCH
OF THE FORECAST AREA REMAINS SHROUDED IN FOG AND VERY LOW CEILINGS
AS THE WARMER AIR ADVECTS IN OVERTOP OF THE STRONG INVERSION NOTED
IN THE LOW LEVELS AND INTERACTS WITH THE REMNANT SNOW/ICE AND
SATURATED GROUND. EXPECT FOG TO REMAIN THE MAIN ISSUE OVER THE
NEXT FEW HOURS AS THE INVERSION IS SLATED TO ONLY SLOWLY GIVE WAY
THROUGH 04Z.
SQUALL LINE DEVELOPMENT HAS COMMENCED OVER THE LAST HOUR OR SO
OVER ARKANSAS WITH ISOLATED CONVECTIVE DEVELOPMENT ALREADY AS FAR
NORTH AS SOUTHWEST INDIANA AND SOUTHERN ILLINOIS. HRRR SEEMS TO
HAVE A VERY NICE FEEL ON THE CURRENT STATE OF THE CONVECTION TO
OUR SOUTHWEST AND EXPECTED EVOLUTION OF THE SQUALL LINE AS MUCAPES
APPROACHING 500J/KG EXPAND INTO THE WABASH VALLEY BY 04-05Z.
TEMPERATURES WILL STEADILY WARM THROUGH THE EVENING WITH ALL OF
THE FORECAST AREA CLIMBING INTO THE 40S AND LOW/MID 50S QUITE
LIKELY OVER SOUTHERN PORTIONS OF CENTRAL INDIANA PRIOR TO THE
ARRIVAL OF THE SQUALL LINE.
MOST RECENT SHORT-RANGE MODEL GUIDANCE SUGGESTING THAT ARRIVAL OF
THE QLCS/SQUALL LINE INTO THE WABASH VALLEY MAY BE AN HOUR OR SO
SLOWER THAN PREVIOUSLY THOUGHT...REACHING THE INDIANA-ILLINOIS
STATE LINE BETWEEN 05 AND 06Z. THE LINE WILL THEN TRACK RAPIDLY
EAST ACROSS THE FORECAST AREA THROUGH 09-10Z. DESPITE THE LACK OF
SIGNIFICANT INSTABILITY...THE DYNAMICS AND FORCING ALOFT MORE THAN
COMPENSATE AND THE ABUNDANCE OF BL SHEAR AND STORM RELATIVE
HELICITY FURTHER SUPPORT A MAINTAINED INTENSITY TO CONVECTION
ACROSS THE REGION ALL NIGHT. QUESTIONS STILL REMAIN WITH REGARDS
TO HOW MUCH THE SHALLOW LOW LEVEL INVERSION WILL IMPEDE WINDS
ALOFT FROM BEING PULLED TO THE SURFACE...ESPECIALLY ACROSS
NORTHERN COUNTIES WHERE THE INVERSION WILL LIKELY MAINTAIN THE
LONGEST. REGARDLESS...THE STRENGTH OF THE LOW LEVEL JET AND THE
FORWARD SPEED OF THE SQUALL LINE SHOULD BE MORE THAN SUFFICIENT TO
PRESENT A DAMAGING WIND POTENTIAL. THIS REMAINS THE PRIMARY
THREAT...WITH ISOLATED TORNADOES...LARGE HAIL AND HEAVY RAINFALL
ALSO POSSIBLE. THE POTENTIAL FOR A HALF INCH TO ONE INCH OF
RAINFALL IN A 3-4 HOUR PERIOD DOES POSE SOME CONCERNS FOR
LOCALIZED FLOODING...ESPECIALLY CONSIDERING THE SATURATED STATE
OF THE GROUND.
HAVE FRESHENED ALL PRODUCTS FOR THE EVENING...INCLUDING GRIDS AND
ZONE FORECAST.
.NEAR TERM /TONIGHT/...
LOTS OF ISSUES TO DEAL WITH IN THE NEAR TERM. MOST POTENT WILL BE
THE POTENTIAL FOR SEVERE CONVECTIVE WEATHER OVERNIGHT AHEAD OF
STRONG COLD FRONT.
ALTHOUGH WARM AIR IS SLOW IN COMING...LOOKING UPSTREAM SOME OF IT
SHOULD STILL GET HERE IN TIME FOR THE FORCING AHEAD OF THE FRONT.
TEMPERATURES MAY NOT BE QUITE AS WARM AS MODEL SHOWS...ESPECIALLY
NORTH WHERE THE SNOW COVER IS. BEST INSTABILITY WILL BE ALOFT
ANYWAY. ALTHOUGH EVEN THAT INSTABILITY WILL BE RELATIVELY
WEAK...THE VERY STRONG WINDS ALOFT WILL CREATE STRONG SHEAR.
850MB WINDS WILL BE UP TO 6 STANDARD DEVIATIONS ABOVE AVERAGE. EVEN
925MB WINDS WILL BE OVER 50KT...WITH GFS SHOWING 60-70KT IN
SOUTHWEST INDIANA. THUS THE SHEAR PLUS THE STRONG LIFT SHOULD
OVERCOME THE LACK OF INSTABILITY FOR STRONG THUNDERSTORMS...ESPECIALLY
ACROSS THE SOUTHERN FORECAST AREA WHERE BEST SHEAR WILL BE.
THE STORMS WILL HAVE TO PUSH THROUGH A DECENT INVERSION TO GET THE
DAMAGING WINDS TO THE SURFACE. THIS WILL AGAIN WILL BE EASIEST
ACROSS THE SOUTHERN FORECAST AREA WHERE TEMPERATURES WILL BE WARMER.
KEEP IN MIND THIS INVERSION HAS THE POTENTIAL TO LIMIT THE SEVERE
WEATHER IF IT IS STRONG ENOUGH. HOWEVER EVEN IF THE WINDS THAT
MAKE IT TO THE SURFACE ARE NON SEVERE...THE WET GROUND MAY ALLOW
TREES TO FALL DOWN EASIER.
THUS WILL MENTION SEVERE STORMS IN THE FORECAST. CURRENT TIMING
LOOKS TO BE 05-10Z. PRIMARY THREAT WILL BE THE DAMAGING WINDS...BUT
WITH THE STRONG SHEAR CANNOT RULE OUT TORNADOES.
THE OTHER PROBLEM WILL BE FLOODING POTENTIAL. EVEN A HALF INCH OF
RAIN MAY CAUSE AREAL FLOODING...AND THIS LINE DEFINITELY HAS THE
POTENTIAL TO DROP A HALF INCH. WILL CONTINUE TO MENTION FLOODING
POTENTIAL IN HWO.
TEMPERATURE FORECAST WILL BE TRICKY...WITH THE SLOW MOVEMENT OF THE
WARM AIR NORTH THIS AFTERNOON. WILL USE RUC AS A PART OF THE FIRST
GUESS AS LOW TEMPERATURES SHOULD OCCUR AT 00Z. READINGS WILL RISE
OVERNIGHT AND PERHAPS BEGIN TO FALL LATE TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
FOCUS IS ON WINDS ON MONDAY. MODELS ARE SIMILAR ENOUGH SO THAT A
BLEND CAN BE USED FOR THE MOST PART.
ACTUAL COLD FRONT WILL PASS ACROSS THE AREA EARLY ON MONDAY. STRONG
WINDS COULD STILL MIX DOWN WITH ANY SHOWERS THAT DEVELOP ALONG THIS
FRONT. ALSO...WITH STRONG PRESSURE RISES BEHIND THE FRONT...THERE
WILL BE GUSTY WINDS THROUGHOUT THE DAY. BUFKIT SHOWS GUSTS NEAR 45
MPH POSSIBLE...ESPECIALLY ACROSS THE NORTHERN FORECAST AREA.
THUS WILL ISSUE A WIND ADVISORY ON MONDAY FOR 12Z-22Z. FAR SOUTHERN
FORECAST AREA IS MORE BORDERLINE...BUT WOULD RATHER BE
PESSIMISTIC...ESPECIALLY WITH POTENTIAL GUSTS ALONG FRONT ITSELF.
THERE LOOKS TO BE ENOUGH FORCING ALONG THE FRONT AND EVEN BEHIND IT
FOR A CHANCE FOR SHOWERS MONDAY MORNING. DURING THE AFTERNOON
MOISTURE AND FORCING ARE LIMITED. BY AFTERNOON ALSO TEMPERATURES
WILL BE COLD ENOUGH FOR SOME SNOW AS WELL. THUS WILL GO WITH
SPRINKLES OR FLURRIES MONDAY AFTERNOON.
TEMPERATURES WILL FALL ON MONDAY WITH HIGHS AT 12Z JUST AHEAD OF THE
FRONT.
DRY WEATHER WILL THEN MOVE IN MONDAY NIGHT INTO TUESDAY NIGHT WITH
HIGH PRESSURE MOVING IN. A BLEND OF MOS LOOKS OK FOR TEMPERATURES.
A SOUTHERN SYSTEM WILL MOVE NORTH ON WEDNESDAY WITH RAIN TRYING TO
WORK INTO THE AREA. THE MOISTURE WILL HAVE TO DISPLACE DRIER AIR
ASSOCIATED WITH HIGH PRESSURE TO THE NORTH. FOR NOW WILL JUST PUT
SLIGHT CHANCES FOR RAIN ACROSS THE FAR SOUTH DURING THE AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE MAIN CONCERN IN THE EXTENDED WILL BE POPS WEDNESDAY NIGHT AND
THURSDAY AS WELL AS FRIDAY NIGHT AS SEPARATE SYSTEMS IMPACT CENTRAL
INDIANA.
ALTHOUGH THE MODELS HAVE SOME TIMING ISSUES AS WELL AS ISSUES ABOUT
HOW FAR NORTH THE PRECIPITATION SHIELD WILL MAKE IT WEDNESDAY NIGHT
AND THURSDAY. BASIC SCENARIO HAS MOIST AIR RETURNING NORTHWARD FROM
THE GULF OF MEXICO OVERTOP A SOUTHERN WARM FRONT AND BEING LIFTED BY
A COLD FRONT APPROACHING FROM THE NORTHERN PLAINS. CENTRAL REGION
INITIALIZATION SEEMS TO HANDLE THINGS OK BRINGING CHANCE POPS TO ALL
OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY SIDING MORE WITH THE
00Z AND 12Z ECMWF. WENT WITH A MIX WEDNESDAY NIGHT AND THURSDAY
MORNING AS TEMPERATURES LOOK TO BOTTOM OUT IN THE UPPER 20S AND
LOWER 30S. WILL ONLY GO WITH RAIN ON THURSDAY AFTERNOON WITH
TEMPERATURES IN THE 40S.
LOOKS LIKE ANOTHER CHANCE FOR A RAIN AND SNOW MIX FRIDAY NIGHT AS
ANOTHER COLD FRONT DROPS DOWN FROM THE NORTHWEST. OTHERWISE...HIGH
PRESSURE SHOULD KEEP IT DRY. JET STREAM FLOW OFF THE PACIFIC
SUGGESTS WARMER THAN NORMAL TEMPERATURES THROUGH FRIDAY BUT BECOMING
MORE NEAR NORMAL STARTING SATURDAY AS INTERIOR CANADIAN WAVE DROPS
DOWN ACROSS THE LOWER GREAT LAKES.
&&
.AVIATION /DISCUSSION FOR THE 23/00Z TAF ISSUANCE/...
VLIFR/LIFR WILL CONTINUE UNTIL THE PERSISTENT TEMPERATURE
INVERSION BREAKS...WHICH WILL NOT BE UNTIL AFTER FRONTAL PASSAGE
LATER TONIGHT. A LINE OF STRONG TO SEVERE THUNDERSTORMS IS
EXPECTED WITH THAT COLD FRONT...AND SHOULD START ENTERING TAF
SITES AROUND MON 06Z. THE BULK OF THE CONVECTION WILL BE IN THE
MON 06-12Z TIME FRAME. AFTER THAT...VISIBILITIES SHOULD IMPROVE
SIGNIFICANTLY...AND TAFS SHOULD RETURN TO MVFR CATEGORY.
THERE IS STILL CONCERN IN REGARD TO WIND SHEAR AHEAD OF THE
AFOREMENTIONED FRONT. WINDS WILL STILL BE LIGHT AT THE
SURFACE...BUT A LOW LEVEL JET WILL INCREASE WINDS UNDER THE
INVERSION. UNTIL THE INVERSION BREAKS AND WINDS CAN MIX
DOWN...WIND SHEAR WILL REMAIN A THREAT.
THE SHEAR THREAT WILL DIMINISH AFTER MON 06Z...BUT SURFACE WINDS
WILL REMAIN STRONG AND SLOWLY VEER TO THE SOUTHWEST. SUSTAINED WIND
SPEEDS WILL RANGE FROM 15 TO 25 KTS WITH GUSTS UP TO 35 KTS
THROUGH TOMORROW AFTERNOON. THEY WILL FINALLY RELAX BY LATE
AFTERNOON AND BECOME MORE WESTERLY.
AT THIS TIME...WANTED TO BUMP CONDITIONS UP TO VFR CATEGORY BY
TOMORROW EVENING...BUT THAT MAY STILL BE A BIT TOO OPTIMISTIC AT
THIS POINT. AS A RESULT...WILL KEEP THEM AT MVFR THROUGH END OF
TAF PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 7 AM TO 5 PM EST MONDAY FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...TDUD
MESOSCALE UPDATE...RYAN
AREA FORECAST DISCUSSION...CORRECTED FORMAT
NWS INDIANAPOLIS IN
701 PM EST SUN JAN 22 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT AND
MONDAY...BRINGING POTENTIALLY SEVERE THUNDERSTORMS...STRONG
WINDS...AND HEAVY RAIN. MUCH COLDER AIR WILL FLOW IN BEHIND THE
FRONT. DRY WEATHER WILL THEN CONTINUE UNTIL MID TO LATE WEEK WHEN A
COUPLE OF SYSTEMS COULD BRING SOME LIGHT PRECIPITATION.
&&
.NEAR TERM /TONIGHT/...
LOTS OF ISSUES TO DEAL WITH IN THE NEAR TERM. MOST POTENT WILL BE
THE POTENTIAL FOR SEVERE CONVECTIVE WEATHER OVERNIGHT AHEAD OF
STRONG COLD FRONT.
ALTHOUGH WARM AIR IS SLOW IN COMING...LOOKING UPSTREAM SOME OF IT
SHOULD STILL GET HERE IN TIME FOR THE FORCING AHEAD OF THE FRONT.
TEMPERATURES MAY NOT BE QUITE AS WARM AS MODEL SHOWS...ESPECIALLY
NORTH WHERE THE SNOW COVER IS. BEST INSTABILITY WILL BE ALOFT
ANYWAY. ALTHOUGH EVEN THAT INSTABILITY WILL BE RELATIVELY
WEAK...THE VERY STRONG WINDS ALOFT WILL CREATE STRONG SHEAR.
850MB WINDS WILL BE UP TO 6 STANDARD DEVIATIONS ABOVE AVERAGE. EVEN
925MB WINDS WILL BE OVER 50KT...WITH GFS SHOWING 60-70KT IN
SOUTHWEST INDIANA. THUS THE SHEAR PLUS THE STRONG LIFT SHOULD
OVERCOME THE LACK OF INSTABILITY FOR STRONG THUNDERSTORMS...ESPECIALLY
ACROSS THE SOUTHERN FORECAST AREA WHERE BEST SHEAR WILL BE.
THE STORMS WILL HAVE TO PUSH THROUGH A DECENT INVERSION TO GET THE
DAMAGING WINDS TO THE SURFACE. THIS WILL AGAIN WILL BE EASIEST
ACROSS THE SOUTHERN FORECAST AREA WHERE TEMPERATURES WILL BE WARMER.
KEEP IN MIND THIS INVERSION HAS THE POTENTIAL TO LIMIT THE SEVERE
WEATHER IF IT IS STRONG ENOUGH. HOWEVER EVEN IF THE WINDS THAT
MAKE IT TO THE SURFACE ARE NON SEVERE...THE WET GROUND MAY ALLOW
TREES TO FALL DOWN EASIER.
THUS WILL MENTION SEVERE STORMS IN THE FORECAST. CURRENT TIMING
LOOKS TO BE 05-10Z. PRIMARY THREAT WILL BE THE DAMAGING WINDS...BUT
WITH THE STRONG SHEAR CANNOT RULE OUT TORNADOES.
THE OTHER PROBLEM WILL BE FLOODING POTENTIAL. EVEN A HALF INCH OF
RAIN MAY CAUSE AREAL FLOODING...AND THIS LINE DEFINITELY HAS THE
POTENTIAL TO DROP A HALF INCH. WILL CONTINUE TO MENTION FLOODING
POTENTIAL IN HWO.
TEMPERATURE FORECAST WILL BE TRICKY...WITH THE SLOW MOVEMENT OF THE
WARM AIR NORTH THIS AFTERNOON. WILL USE RUC AS A PART OF THE FIRST
GUESS AS LOW TEMPERATURES SHOULD OCCUR AT 00Z. READINGS WILL RISE
OVERNIGHT AND PERHAPS BEGIN TO FALL LATE TONIGHT.
WARM AIR MOVING OVER THE SNOW COVER ACROSS THE NORTH COULD LEAD TO
PATCHY DENSE FOG TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
FOCUS IS ON WINDS ON MONDAY. MODELS ARE SIMILAR ENOUGH SO THAT A
BLEND CAN BE USED FOR THE MOST PART.
ACTUAL COLD FRONT WILL PASS ACROSS THE AREA EARLY ON MONDAY. STRONG
WINDS COULD STILL MIX DOWN WITH ANY SHOWERS THAT DEVELOP ALONG THIS
FRONT. ALSO...WITH STRONG PRESSURE RISES BEHIND THE FRONT...THERE
WILL BE GUSTY WINDS THROUGHOUT THE DAY. BUFKIT SHOWS GUSTS NEAR 45
MPH POSSIBLE...ESPECIALLY ACROSS THE NORTHERN FORECAST AREA.
THUS WILL ISSUE A WIND ADVISORY ON MONDAY FOR 12Z-22Z. FAR SOUTHERN
FORECAST AREA IS MORE BORDERLINE...BUT WOULD RATHER BE
PESSIMISTIC...ESPECIALLY WITH POTENTIAL GUSTS ALONG FRONT ITSELF.
THERE LOOKS TO BE ENOUGH FORCING ALONG THE FRONT AND EVEN BEHIND IT
FOR A CHANCE FOR SHOWERS MONDAY MORNING. DURING THE AFTERNOON
MOISTURE AND FORCING ARE LIMITED. BY AFTERNOON ALSO TEMPERATURES
WILL BE COLD ENOUGH FOR SOME SNOW AS WELL. THUS WILL GO WITH
SPRINKLES OR FLURRIES MONDAY AFTERNOON.
TEMPERATURES WILL FALL ON MONDAY WITH HIGHS AT 12Z JUST AHEAD OF THE
FRONT.
DRY WEATHER WILL THEN MOVE IN MONDAY NIGHT INTO TUESDAY NIGHT WITH
HIGH PRESSURE MOVING IN. A BLEND OF MOS LOOKS OK FOR TEMPERATURES.
A SOUTHERN SYSTEM WILL MOVE NORTH ON WEDNESDAY WITH RAIN TRYING TO
WORK INTO THE AREA. THE MOISTURE WILL HAVE TO DISPLACE DRIER AIR
ASSOCIATED WITH HIGH PRESSURE TO THE NORTH. FOR NOW WILL JUST PUT
SLIGHT CHANCES FOR RAIN ACROSS THE FAR SOUTH DURING THE AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE MAIN CONCERN IN THE EXTENDED WILL BE POPS WEDNESDAY NIGHT AND
THURSDAY AS WELL AS FRIDAY NIGHT AS SEPARATE SYSTEMS IMPACT CENTRAL
INDIANA.
ALTHOUGH THE MODELS HAVE SOME TIMING ISSUES AS WELL AS ISSUES ABOUT
HOW FAR NORTH THE PRECIPITATION SHIELD WILL MAKE IT WEDNESDAY NIGHT
AND THURSDAY. BASIC SCENARIO HAS MOIST AIR RETURNING NORTHWARD FROM
THE GULF OF MEXICO OVERTOP A SOUTHERN WARM FRONT AND BEING LIFTED BY
A COLD FRONT APPROACHING FROM THE NORTHERN PLAINS. CENTRAL REGION
INITIALIZATION SEEMS TO HANDLE THINGS OK BRINGING CHANCE POPS TO ALL
OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY SIDING MORE WITH THE
00Z AND 12Z ECMWF. WENT WITH A MIX WEDNESDAY NIGHT AND THURSDAY
MORNING AS TEMPERATURES LOOK TO BOTTOM OUT IN THE UPPER 20S AND
LOWER 30S. WILL ONLY GO WITH RAIN ON THURSDAY AFTERNOON WITH
TEMPERATURES IN THE 40S.
LOOKS LIKE ANOTHER CHANCE FOR A RAIN AND SNOW MIX FRIDAY NIGHT AS
ANOTHER COLD FRONT DROPS DOWN FROM THE NORTHWEST. OTHERWISE...HIGH
PRESSURE SHOULD KEEP IT DRY. JET STREAM FLOW OFF THE PACIFIC
SUGGESTS WARMER THAN NORMAL TEMPERATURES THROUGH FRIDAY BUT BECOMING
MORE NEAR NORMAL STARTING SATURDAY AS INTERIOR CANADIAN WAVE DROPS
DOWN ACROSS THE LOWER GREAT LAKES.
&&
.AVIATION /DISCUSSION FOR THE 23/00Z TAF ISSUANCE/...
VLIFR/LIFR WILL CONTINUE UNTIL THE PERSISTENT TEMPERATURE
INVERSION BREAKS...WHICH WILL NOT BE UNTIL AFTER FRONTAL PASSAGE
LATER TONIGHT. A LINE OF STRONG TO SEVERE THUNDERSTORMS IS
EXPECTED WITH THAT COLD FRONT...AND SHOULD START ENTERING TAF
SITES AROUND MON 06Z. THE BULK OF THE CONVECTION WILL BE IN THE
MON 06-12Z TIME FRAME. AFTER THAT...VISIBILITIES SHOULD IMPROVE
SIGNIFICANTLY...AND TAFS SHOULD RETURN TO MVFR CATEGORY.
THERE IS STILL CONCERN IN REGARD TO WIND SHEAR AHEAD OF THE
AFOREMENTIONED FRONT. WINDS WILL STILL BE LIGHT AT THE
SURFACE...BUT A LOW LEVEL JET WILL INCREASE WINDS UNDER THE
INVERSION. UNTIL THE INVERSION BREAKS AND WINDS CAN MIX
DOWN...WIND SHEAR WILL REMAIN A THREAT.
THE SHEAR THREAT WILL DIMINISH AFTER MON 06Z...BUT SURFACE WINDS
WILL REMAIN STRONG AND SLOWLY VEER TO THE SOUTHWEST. SUSTAINED WIND
SPEEDS WILL RANGE FROM 15 TO 25 KTS WITH GUSTS UP TO 35 KTS
THROUGH TOMORROW AFTERNOON. THEY WILL FINALLY RELAX BY LATE
AFTERNOON AND BECOME MORE WESTERLY.
AT THIS TIME...WANTED TO BUMP CONDITIONS UP TO VFR CATEGORY BY
TOMORROW EVENING...BUT THAT MAY STILL BE A BIT TOO OPTIMISTIC AT
THIS POINT. AS A RESULT...WILL KEEP THEM AT MVFR THROUGH END OF
TAF PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 7 AM TO 5 PM EST MONDAY FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
820 PM EDT SUN MAY 29 2011
.UPDATE...
NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL RESULT IN ABOVE NORMAL TEMPS ACROSS
CENTRAL INDIANA THROUGH MID WEEK. HIGHS WILL TOP OFF IN THE
90S...AND CONDITIONS WILL BE HUMID. THERE WILL BE A BRIEF REPRIEVE
IN THE HEAT AROUND MID WEEK AS A COLD FRONT ASSOCIATED WITH A LOW
PRESSURE SYSTEM OVER CANADA MOVES ACROSS THE FORECAST AREA. BEYOND
THAT...THE RIDGE WILL BUILD BACK INTO THE REGION...AND HOT WEATHER
WILL RETURN FOR NEXT WEEKEND.
&&
.NEAR TERM /TONIGHT/...
RADAR SHOWS A FEW LIGHT SHOWERS JUST NORTH OF CARROLL AND WARREN
COUNTIES AND CURRENT LOOPS KEEP THEM JUST TO OUR NORTH FOR ANOTHER
HOUR OR TWO BEFORE MOVING ON. OTHERWISE...GOING FORECAST SEEMS TO
BE ON TRACK. THE ONLY CHANGE WAS TO LOWER WIND SPEEDS A LITTLE LATER
TONIGHT AS SOME DECOUPLING OCCURS.
HIGH CLOUDS CURRENTLY ACROSS OUR REGION SHOULD CLEAR OUT OVERNIGHT
AS UPPER RIDGE BUILDS AND CONVECTIVE COMPLEX TO OUR NORTHEAST MOVES
AWAY. LOW TEMPERATURES MOST AREAS WILL BE IN THE UPPER 60S.
&&
.SHORT TERM /TOMORROW THROUGH WEDNESDAY NIGHT/...
UPDATE FOR MONDAY...LOWERED TEMPERATURES A DEGREE OR TWO MOST AREAS
FOR MONDAY BASED ON TEMPERATURES UPSTREAM AND HIGH SOIL MOISTURE
CONTENT ACROSS OUR REGION AS OPPOSED TO DEEP SOUTH WHICH IS
PRESENTLY IN A MODERATE DROUGHT. EVEN IN THE DEEP SOUTH...ONLY A FEW
AREAS SAW TEMPERATURES IN THE MID 90S TODAY AND MODELS INDICATE 850
MB TEMPERATURES WILL NOT BE THAT MUCH WARMER MONDAY AFTERNOON THAN
THEY WERE TODAY.
PREVIOUS DISCUSSION...THE MAIN FOCUS OF THE SHORT TERM IS THE
EXTREMELY HOT TEMPERATURES AND THE WEAK COLD FRONT PROGGED TO MOVE
ACROSS CENTRAL INDIANA ON TUESDAY AND WEDNESDAY.
ABOVE NORMAL TEMPS IN THE LOW TO MID 90S WILL PERSIST TOMORROW AND
TUESDAY AS A RIDGE OF HIGH PRESSURE REMAINS OVER THE EASTERN THIRD
OF THE NATION. TIME CROSS SECTIONS ARE STILL SHOWING 850 MB TEMPS
OF 22C...AND WINDS WILL BE STRONG OUT OF THE SOUTH/SOUTHWEST. IN
ADDITION...AMPLE SUNSHINE WILL CONTRIBUTE TO THE AFTERNOON
HEATING. SO...CONTINUED TO LEAN ON THE HIGHER SIDE OF GUIDANCE.
THE NAM SEEMED A BIT COOL FOR TOMORROW...SO WENT WITH THE GFS.
HOWEVER...THEY COME INTO LINE ON TUESDAY.
TUESDAY...A LOW PRESSURE SYSTEM WILL MOVE ACROSS CANADA...AND ITS
ASSOCIATED COLD FRONT WILL SWEEP ACROSS CENTRAL INDIANA.
HOWEVER...WILL CONTINUE TO TREND ON THE WARM SIDE WITH HIGHS IN THE
90S BECAUSE ANY SHOWERS OR THUNDERSTORMS THAT DO DEVELOP WILL BE
LATE IN THE DAY AND OVERNIGHT. SO...TEMPS WILL HAVE ENOUGH TIME TO
CLIMB INTO THE 90S. PLUS...MOISTURE IS LACKING AND DID NOT GO ABOVE
CHANCE POPS ANYWHERE AT ANY TIME.
TUESDAY NIGHT LOWS...NAM SEEMED A BIT TOO COOL WITH THE CLOUD
COVER AND ANY RAIN THAT DEVELOPS. SO...WENT WITH THE GFS/S UPPER
60S. TEMPS ON WEDNESDAY WILL BE A TAD COOLER BEHIND AFOREMENTIONED
COLD FRONT...BUT NOT BY MUCH. HIGHS WILL STILL TOP OFF IN THE 80S.
HIGH PRESSURE WILL RE-ESTABLISH ITSELF ON WEDNESDAY...AND TEMPS
WILL START CREEPING BACK INTO THE 90S BY THE WEEKEND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
FRONTAL BOUNDARY WILL LIFT BACK NORTH AS A WARM FRONT WEDNESDAY
NIGHT AND THURSDAY...WITH A RESUMPTION OF THE HOT HUMID WEATHER
PATTERN FOR FRIDAY INTO THE WEEKEND AS THE RIDGING ALOFT
REESTABLISHES OVER THE OHIO VALLEY. LIKELY TO SEE ISOLATED TO
SCATTERED THUNDERSTORMS WITH THE WARM FRONT AND WILL MAINTAIN 20-30
POPS THROUGH THURSDAY AFTERNOON. FROM THAT POINT FORWARD...CORE OF
THE UPPER RIDGE SETS UP OVER THE OHIO AND MID MISSISSIPPI VALLEYS.
850MB TEMPS ONCE AGAIN CLIMB INTO THE 20-22C RANGE FOR FRIDAY AND
SATURDAY WITH HIGHS RETURNING TO AROUND 90 DEGREES. PASSAGE OF AN
UPPER LEVEL LOW NORTH OF THE GREAT LAKES MAY CAUSE SOME BUCKLING OF
THE RIDGE FOR SUNDAY. THIS COULD BRING ANY RIDGE RIDER CONVECTION
BACK SOUTH INTO THE FORECAST AREA FOR SUNDAY. HOWEVER WITH SOME
DISCREPANCY BETWEEN THE EXTENDED MODELS WITH RESPECT TO TIMING AND
EXTENT OF THE SUPPRESSION OF THE RIDGE...HAVE CHOSEN TO LEAVE SUNDAY
DRY AT THIS TIME.
&&
.AVIATION.../DISCUSSION FOR 300000Z TAFS/...
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE FORECAST PERIOD. DURING
THE AFTERNOON HOURS AN MCS TRACKING EASTWARD ACROSS THE WARM FRONT
JUST NORTH OF THE CWA GENERATED AN OUTFLOW BOUNDARY THAT PUSHED
SOUTHWARD ACROSS KLAF BUT HAS SLOWED ITS PROPAGATION AND SHOULD NOT
AFFECT OTHER TAF SITES. THEREFORE WINDS AT KLAF WILL LIKELY BE
SOUTHEASTERLY THIS EVENING BEFORE SHIFTING TO SOUTHERLY. CIRRUS
GENERATED FROM PREVIOUS CONVECTION WILL CONTINUE TO DISSIPATE THIS
EVENING.
NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST AT THIS TIME.
PREVIOUS DISCUSSION FOLLOWS WITH MINOR REVISIONS.
REMAINDER OF THE FORECAST LOOKS QUIET AS RIDGE ALOFT FIRMLY
ENTRENCHES OVER THE OHIO VALLEY. DEEPER SUBSIDENCE ASSOCIATED WITH
HIGH PRESSURE WILL SPREAD ACROSS THE FORECAST AREA TONIGHT AND
MONDAY WITH MAINLY CLEAR SKIES. SOUTHERLY WINDS AT 5-10KTS
OVERNIGHT WILL ONCE AGAIN VEER TO SOUTHWEST ON MONDAY AT 10-15KTS.
LOCALLY HIGHER GUSTS 15-20KTS ARE POSSIBLE MONDAY AT KLAF AND KHUF.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...JH
SHORT TERM...TDUD/JH
LONG TERM....RYAN
AVIATION...AB/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
652 PM EST SUN JAN 22 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT AND
MONDAY...BRINGING POTENTIALLY SEVERE THUNDERSTORMS...STRONG
WINDS...AND HEAVY RAIN. MUCH COLDER AIR WILL FLOW IN BEHIND THE
FRONT. DRY WEATHER WILL THEN CONTINUE UNTIL MID TO LATE WEEK WHEN A
&&
.NEAR TERM /TONIGHT/...
LOTS OF ISSUES TO DEAL WITH IN THE NEAR TERM. MOST POTENT WILL BE
THE POTENTIAL FOR SEVERE CONVECTIVE WEATHER OVERNIGHT AHEAD OF
STRONG COLD FRONT.
ALTHOUGH WARM AIR IS SLOW IN COMING...LOOKING UPSTREAM SOME OF IT
SHOULD STILL GET HERE IN TIME FOR THE FORCING AHEAD OF THE FRONT.
TEMPERATURES MAY NOT BE QUITE AS WARM AS MODEL SHOWS...ESPECIALLY
NORTH WHERE THE SNOW COVER IS. BEST INSTABILITY WILL BE ALOFT
ANYWAY. ALTHOUGH EVEN THAT INSTABILITY WILL BE RELATIVELY
WEAK...THE VERY STRONG WINDS ALOFT WILL CREATE STRONG SHEAR.
850MB WINDS WILL BE UP TO 6 STANDARD DEVIATIONS ABOVE AVERAGE. EVEN
925MB WINDS WILL BE OVER 50KT...WITH GFS SHOWING 60-70KT IN
SOUTHWEST INDIANA. THUS THE SHEAR PLUS THE STRONG LIFT SHOULD
OVERCOME THE LACK OF INSTABILITY FOR STRONG THUNDERSTORMS...ESPECIALLY
ACROSS THE SOUTHERN FORECAST AREA WHERE BEST SHEAR WILL BE.
THE STORMS WILL HAVE TO PUSH THROUGH A DECENT INVERSION TO GET THE
DAMAGING WINDS TO THE SURFACE. THIS WILL AGAIN WILL BE EASIEST
ACROSS THE SOUTHERN FORECAST AREA WHERE TEMPERATURES WILL BE WARMER.
KEEP IN MIND THIS INVERSION HAS THE POTENTIAL TO LIMIT THE SEVERE
WEATHER IF IT IS STRONG ENOUGH. HOWEVER EVEN IF THE WINDS THAT
MAKE IT TO THE SURFACE ARE NON SEVERE...THE WET GROUND MAY ALLOW
TREES TO FALL DOWN EASIER.
THUS WILL MENTION SEVERE STORMS IN THE FORECAST. CURRENT TIMING
LOOKS TO BE 05-10Z. PRIMARY THREAT WILL BE THE DAMAGING WINDS...BUT
WITH THE STRONG SHEAR CANNOT RULE OUT TORNADOES.
THE OTHER PROBLEM WILL BE FLOODING POTENTIAL. EVEN A HALF INCH OF
RAIN MAY CAUSE AREAL FLOODING...AND THIS LINE DEFINITELY HAS THE
POTENTIAL TO DROP A HALF INCH. WILL CONTINUE TO MENTION FLOODING
POTENTIAL IN HWO.
TEMPERATURE FORECAST WILL BE TRICKY...WITH THE SLOW MOVEMENT OF THE
WARM AIR NORTH THIS AFTERNOON. WILL USE RUC AS A PART OF THE FIRST
GUESS AS LOW TEMPERATURES SHOULD OCCUR AT 00Z. READINGS WILL RISE
OVERNIGHT AND PERHAPS BEGIN TO FALL LATE TONIGHT.
WARM AIR MOVING OVER THE SNOW COVER ACROSS THE NORTH COULD LEAD TO
PATCHY DENSE FOG TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
FOCUS IS ON WINDS ON MONDAY. MODELS ARE SIMILAR ENOUGH SO THAT A
BLEND CAN BE USED FOR THE MOST PART.
ACTUAL COLD FRONT WILL PASS ACROSS THE AREA EARLY ON MONDAY. STRONG
WINDS COULD STILL MIX DOWN WITH ANY SHOWERS THAT DEVELOP ALONG THIS
FRONT. ALSO...WITH STRONG PRESSURE RISES BEHIND THE FRONT...THERE
WILL BE GUSTY WINDS THROUGHOUT THE DAY. BUFKIT SHOWS GUSTS NEAR 45
MPH POSSIBLE...ESPECIALLY ACROSS THE NORTHERN FORECAST AREA.
THUS WILL ISSUE A WIND ADVISORY ON MONDAY FOR 12Z-22Z. FAR SOUTHERN
FORECAST AREA IS MORE BORDERLINE...BUT WOULD RATHER BE
PESSIMISTIC...ESPECIALLY WITH POTENTIAL GUSTS ALONG FRONT ITSELF.
THERE LOOKS TO BE ENOUGH FORCING ALONG THE FRONT AND EVEN BEHIND IT
FOR A CHANCE FOR SHOWERS MONDAY MORNING. DURING THE AFTERNOON
MOISTURE AND FORCING ARE LIMITED. BY AFTERNOON ALSO TEMPERATURES
WILL BE COLD ENOUGH FOR SOME SNOW AS WELL. THUS WILL GO WITH
SPRINKLES OR FLURRIES MONDAY AFTERNOON.
TEMPERATURES WILL FALL ON MONDAY WITH HIGHS AT 12Z JUST AHEAD OF THE
FRONT.
DRY WEATHER WILL THEN MOVE IN MONDAY NIGHT INTO TUESDAY NIGHT WITH
HIGH PRESSURE MOVING IN. A BLEND OF MOS LOOKS OK FOR TEMPERATURES.
A SOUTHERN SYSTEM WILL MOVE NORTH ON WEDNESDAY WITH RAIN TRYING TO
WORK INTO THE AREA. THE MOISTURE WILL HAVE TO DISPLACE DRIER AIR
ASSOCIATED WITH HIGH PRESSURE TO THE NORTH. FOR NOW WILL JUST PUT
SLIGHT CHANCES FOR RAIN ACROSS THE FAR SOUTH DURING THE AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE MAIN CONCERN IN THE EXTENDED WILL BE POPS WEDNESDAY NIGHT AND
THURSDAY AS WELL AS FRIDAY NIGHT AS SEPARATE SYSTEMS IMPACT CENTRAL
INDIANA.
ALTHOUGH THE MODELS HAVE SOME TIMING ISSUES AS WELL AS ISSUES ABOUT
HOW FAR NORTH THE PRECIPITATION SHIELD WILL MAKE IT WEDNESDAY NIGHT
AND THURSDAY. BASIC SCENARIO HAS MOIST AIR RETURNING NORTHWARD FROM
THE GULF OF MEXICO OVERTOP A SOUTHERN WARM FRONT AND BEING LIFTED BY
A COLD FRONT APPROACHING FROM THE NORTHERN PLAINS. CENTRAL REGION
INITIALIZATION SEEMS TO HANDLE THINGS OK BRINGING CHANCE POPS TO ALL
OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY SIDING MORE WITH THE
00Z AND 12Z ECMWF. WENT WITH A MIX WEDNESDAY NIGHT AND THURSDAY
MORNING AS TEMPERATURES LOOK TO BOTTOM OUT IN THE UPPER 20S AND
LOWER 30S. WILL ONLY GO WITH RAIN ON THURSDAY AFTERNOON WITH
TEMPERATURES IN THE 40S.
LOOKS LIKE ANOTHER CHANCE FOR A RAIN AND SNOW MIX FRIDAY NIGHT AS
ANOTHER COLD FRONT DROPS DOWN FROM THE NORTHWEST. OTHERWISE...HIGH
PRESSURE SHOULD KEEP IT DRY. JET STREAM FLOW OFF THE PACIFIC
SUGGESTS WARMER THAN NORMAL TEMPERATURES THROUGH FRIDAY BUT BECOMING
MORE NEAR NORMAL STARTING SATURDAY AS INTERIOR CANADIAN WAVE DROPS
DOWN ACROSS THE LOWER GREAT LAKES.
&&
.AVIATION /DISCUSSION FOR THE 23/00Z TAF ISSUANCE/...
VLIFR/LIFR WILL CONTINUE UNTIL THE PERSISTENT TEMPERATURE
INVERSION BREAKS...WHICH WILL NOT BE UNTIL AFTER FRONTAL PASSAGE
LATER TONIGHT. A LINE OF STRONG TO SEVERE THUNDERSTORMS IS
EXPECTED WITH THAT COLD FRONT...AND SHOULD START ENTERING TAF
SITES AROUND MON 06Z. THE BULK OF THE CONVECTION WILL BE IN THE
MON 06-12Z TIME FRAME. AFTER THAT...VISIBILITIES SHOULD IMPROVE
SIGNIFICANTLY...AND TAFS SHOULD RETURN TO MVFR CATEGORY.
THERE IS STILL CONCERN IN REGARD TO WIND SHEAR AHEAD OF THE
AFOREMENTIONED FRONT. WINDS WILL STILL BE LIGHT AT THE
SURFACE...BUT A LOW LEVEL JET WILL INCREASE WINDS UNDER THE
INVERSION. UNTIL THE INVERSION BREAKS AND WINDS CAN MIX
DOWN...WIND SHEAR WILL REMAIN A THREAT.
THE SHEAR THREAT WILL DIMINISH AFTER MON 06Z...BUT SURFACE WINDS
WILL REMAIN STRONG AND SLOWLY VEER TO THE SOUTHWEST. SUSTAINED WIND
SPEEDS WILL RANGE FROM 15 TO 25 KTS WITH GUSTS UP TO 35 KTS
THROUGH TOMORROW AFTERNOON. THEY WILL FINALLY RELAX BY LATE
AFTERNOON AND BECOME MORE WESTERLY.
AT THIS TIME...WANTED TO BUMP CONDITIONS UP TO VFR CATEGORY BY
TOMORROW EVENING...BUT THAT MAY STILL BE A BIT TOO OPTIMISTIC AT
THIS POINT. AS A RESULT...WILL KEEP THEM AT MVFR THROUGH END OF
TAF PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 7 AM TO 5 PM EST MONDAY FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....MK
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
630 PM EST SUN JAN 22 2012
.AVIATION...
IFR AND LIFR CONDITIONS WILL BE THE BOTTOM LINE WITH THIS TAF
PACKAGE. CIGS AND VIS WILL CONTINUE TO LOWER EARLY THIS EVENING WITH
IMPRESSIVE INVERSION OVER THE REGION. STRONG WARM AIR ADVECTION
ALOFT AND DEEP MOISTURE ADVECTION OVER MELTING SNOWPACK WILL LEAD TO
DENSE FOG DEVELOPMENT DESPITE INCREASING GRADIENT AND SURFACE WINDS
IN EXCESS OF 15 KNOTS. HAVE TRENDED TAFS DOWN GIVEN UPSTREAM
OBSERVATIONS OF ONE HALF TO ONE QUARTER MILE ACROSS IL AND THIS
ENVIRONMENT ADVECTING IN. ATTENTION THEN TURNS QUICKLY TO
APPROACHING POTENT SHORT WAVE AND STRONG KINEMATICS ALONG WITH
ELEVATED INSTABILITY. THIS WILL LEAD TO DEVELOPING LINE OF
THUNDERSTORMS THIS EVENING ACROSS MO AND SOUTHERN IL WHICH ARE
EXPECTED TO MOVE THROUGH TAF SITES AFTER 06Z. USED HRRR AND OTHER
HIRES MODEL GUIDANCE TO TIME TSRA THROUGH TAF SITES. GUSTY TSRA
WINDS POSSIBLE BUT DEPENDENT ON PENETRATING STRONG INVERSION. COLD
AIR ADVECTION THEN EXPECTED MONDAY WITH VERY STRONG WINDS ALONG AND
BEHIND COLD FRONT. CHANGE OVER TO SNOW SHOWERS EXPECTED IN
AFTERNOON.
&&
.SHORT TERM...
TONIGHT THROUGH MONDAY NIGHT
SOUTHERN PLAINS UPPER TROUGH WILL CONTINUE TO EJECT TOWARD THE
REGION TONIGHT...SUPPORTING IMPRESSIVE SFC CYCLOGENESIS AS A MID
LEVEL JET INTERACTS THE WITH THE SFC CYCLONE TO SUPPORT IMPRESSIVE
SFC PRESSURE FALLS. STAUNCH DEEP LAYER THETA-E ADV WILL SUPPORT
DEVELOPING SHOWERS AND THUNDERSTORMS LATE TONIGHT INTO THE AREA...AS
A PRE-FRONTAL THETA-E RIDGE ADVECTS QUICKLY THROUGH THE REGION.
IMPRESSIVE RISE/FALL COUPLET COINCIDENT WITH THE SFC COLD FRONT WILL
ALLOW VERY GUSTY WINDS MONDAY...AS CAA ENSUES...AND COLD AIR FILTERS
BACK INTO THE AREA. FORECAST MODELS HAVE FINALLY CONVERGED ON THE
CONSISTENT ECMWF SOLUTION...ALTHOUGH SOME TIMING DIFFERENCE
REMAIN...PARTICULARLY WITH THE NAM BEING ON THE FAST SIDE OF
SPECTRUM. PREFERENCE REMAINS WITH THE ECMWF...WITH SOME ADJUSTMENT
TO THE HIRES NMM/ARW...WHICH HELP IN FORECASTING CONVECTIVE
POTENTIAL/WINDS/AND FRONTAL TIMING.
WAA WILL CONTINUE WITH A SUBSTANTIAL INVERSION IN PLACE LEADING TO
THE DEVELOPMENT OF DRIZZLE AND FOG AS SIG MOISTURE ADV ENSUES IN THE
SATURATED INVERSION LAYER. RETAINED FOG MENTION THROUGH TONIGHT. LLJ
WILL DEVELOP TONIGHT AND SUPPORT STRONG LL THETA-E RIDGING AT THE
BASE OF A POTENT EML /INDICATED IN 12Z UPSTREAM RAOBS/. ELEVATED
PARCEL BASED INSTABILITY WILL INCREASE AND SUPPORT A BROAD AREA OF
SHOWERS AND THUNDERSTORMS UPSTREAM THE FA...WHICH WILL QUICKLY
ADVECT NE WITH THE PRE-FRONTAL TROUGH. HOWEVER...THE SFC WARM FRONT
WILL REMAIN WELL SOUTH OF THE REGION...WITH AN INVERSION REMAINING
GIVEN SNOW PACK AND STRONG EAST COMPONENT TO THE LL FLOW.
HENCE...SEVERE THUNDERSTORM THREAT WILL REMAIN HIGHLY LIMITED...WITH
THE BEST CHANCE FOR DAMAGING CONVECTIVE WIND IN THE SOUTHERN
FA...GIVEN THE POTENTIAL FOR AN ELEVATED QLCS WITH MID LEVEL FLOW
IMPINGING JET CORES. RETAINED GUSTY WIND TS MENTION ATTM. PERHAPS
THE BEST CHANCE FOR STRONG WIND GUSTS WILL COME WITH THE SFC COLD
FROPA...WHICH IS EXPECTED INTO THE WESTERN FA BY MID MORNING. AN
IMPRESSIVE 20 MB RISE/FALL COUPLET SUPPORTING ISALLOBARIC WIND
VECTORS IN LINE WITH DEEP LAYER LOW-MID LEVEL FLOW AND PERPENDICULAR
TO THE SFC COLD FRONT/H950 GEOSTROPHIC JET CORE IN EXCESS OF 90
KNOTS WITH THE NOSE OF THE JET IMPINGING ON THE SFC COLD FRONT WILL
CREATE A FAVORABLE ENVIRONMENT FOR A DYNAMICALLY FORCED THIN
LINE...CAPABLE OF PRODUCING WIND GUSTS IN EXCESS OF 50 MPH. HIRES
NMM GUST POTENTIAL HIGHLIGHTS THIS THREAT. IN ADDITION...CAA REGIME
WITH A STRONG SFC PRESSURE GRADIENT IN PLACE WILL SUPPORT WIND
ADV/OR NEAR WIND ADV CRITERIA FOR MUCH OF THE DAY MONDAY. HENCE WILL
ISSUE A WIND ADV. HEAVY RAINFALL REMAINS A CONCERN. HOWEVER...GIVEN
THE SFC LOW TRACK NW OF THE REGION...THE LONGEST PERIOD OF DEEP
ASCENT IN THE ASSOCIATED DEFORMATION ZONE WILL OCCUR WELL NW OF THE
REGION. CONVECTIVE PRECIP WITH A PERIOD OF WAA WILL SUPPORT A DECENT
AMOUNT OF RAIN...WITH GENERALLY AROUND ONE HALF INCH POSSIBLE IN THE
WESTERN HALF...IN ADDITION TO SNOW MELT. THIS WILL LIKELY AGGRAVATE
RIVER/CREEK RISES SOME. LL THERMAL RIDGE ARRIVAL AFTER 12Z WILL
SUPPORT MORNING HIGHS WITH FALLING TEMPS THROUGH THE REMAINDER OF
THE DAY.
CAA WILL DOMINATE MONDAY/MON NIGHT WITH FALLING TEMPS IN THE DAYTIME
PERIOD. LINGERING RAIN SHOWERS WILL BE
POSSIBLE MONDAY AFTERNOON BEHIND THE COLD FRONT...TRANSITIONING TO
SNOW SHOWERS WEST TO EAST. SNOW SHOWERS ARE EXPECTED MAINLY NORTH
MONDAY NIGHT AS THE LINGERING DEFORMATION ZONE SKIRTS THE NORTHERN
ZONES. A HALF INCH OR LESS ACCUMS ARE POSSIBLE MAINLY ACROSS THE
NORTHERN THIRD.
&&
.LONG TERM...TUESDAY THROUGH SATURDAY
SPLIT TYPE FLOW PATTERN ACROSS EASTERN PACIFIC/WESTERN CONUS TO
DOMINATE THIS PERIOD WITH CONTINUED PHASING ISSUES LENDING TO
FORECAST UNCERTAINTY FOR THE LONG TERM. ON TUESDAY...CYCLONIC FLOW
ALOFT WILL PERSIST IN ASSOCIATION WITH DEPARTING UPPER LEVEL TROUGH.
LOW LEVEL DRY AIR ADVECTION WILL BE CONTINUING AND QUESTION WILL BE
WHETHER ANY LIGHT SNOW SHOWERS OR FLURRIES PERSIST INTO TUESDAY
MORNING. 12Z FORECAST SOUNDINGS SHOW SOME QUESTION AS TO THE
POTENTIAL OF SATURATION AT TEMPERATURES COLD ENOUGH TO INTRODUCE ICE
FOR LIGHT SNOW OR FLURRIES BUT DO STILL SEE SOME POTENTIAL AND HAVE
MAINTAINED THIS MENTION. THE REMAINDER OF TUESDAY SHOULD FEATURE
DECREASING CLOUDINESS AS SHORT WAVE UPPER RIDGING INDUCED DOWNSTREAM
OF NEXT NORTHERN STREAM TROUGH BUILDS INTO THE AREA. SFC HIGH
BUILDING INTO THE AREA TUESDAY NIGHT SHOULD PROVIDE GOOD RADIATIONAL
COOLING CONDITIONS...BUT WITH PROGRESSIVE NORTHERN STREAM DO SEE A
POTENTIAL FOR INCREASING HIGH CLOUDS AND THUS HAVE STAYED FAIRLY
CONSERVATIVE WITH MINS IN THE LOWER TO MID 20S TUESDAY NIGHT.
WHILE MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT WITH LARGE SCALE
FEATURES MID WEEK...SOME SUBTLE DIFFERENCES IN HANDLING CUT OFF
SOUTHERN STREAM LOW AND SLIGHT TIMING DIFFERENCES IN NORTHERN STREAM
TROUGH PROGRESSION WILL HAVE A LOT TO SAY IN TERMS OF MID WEEK POPS.
CONSENSUS OF MEDIUM RANGE MODELS IS TO BRING WAA FORCING DOWNSTREAM
OF THIS CUT LOW TO AREAS AS FAR NORTH AS CENTRAL INDIANA/NORTHWEST
OHIO WEDNESDAY NIGHT. CUT OFF TO THE NORTHERN EXTENT OF THE POPS
SHOULD BE FAIRLY SHARP AS STRONGER WESTERLIES ASSOCIATED WITH THE
NORTHERN STREAM ABRUPTLY CUT OFF LOW LEVEL MOISTURE TRANSPORT.
LITTLE CHANGE TO PREVIOUS FORECAST WITH LOW CHANCE POPS SOUTHEAST
TRENDING TO SLIGHT CHANCE REMAINDER OF AREA WEDNESDAY NIGHT. DID
ALSO MAINTAIN THESE LOW POPS INTO THURSDAY GIVEN NORTHERN STEAM
TROUGH PASSAGE EXPECTED. MOISTURE WILL BE SOMEWHAT LIMITED WITH THIS
FORCING HOWEVER...AND THUS NOT WARRANTING MORE THAN A LOW CHANCE POP
AT THIS TIME. THERMAL PROFILES STILL MARGINAL FOR THIS PERIOD WITH
PRECIP TYPE DEPENDING ON PROGRESSION OF NORTHERN STREAM...WHICH WILL
IMPACT THE TIMING OF COLD AIR ADVECTION INTO THE GREAT LAKES FROM
THIS NORTHERN STREAM. THUS... KEPT PTYPE AS RAIN OR SNOW.
A DEEPER UPPER TROUGH EXPECTED BY THE FIRST PART OF THE WEEKEND AS
MEDIUM RANGE MODELS DEPICT A FAIRLY STRONG UPPER JET STREAK CARVING
OUT A LARGE NEGATIVE UPPER HEIGHT ANOMALY ACROSS THE GREAT LAKES
REGION. CHANCE OF LIGHT SNOW/SNOW SHOWERS WERE MAINTAINED FOR FRIDAY
NIGHT AND SATURDAY WITH TEMPS BACK TO NEAR NORMAL FOR LATE JANUARY
BY THE END OF THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND ADVISORY FROM 7 AM EST /6 AM CST/ TO 5 PM EST /4 PM CST/
MONDAY FOR INZ003>009-012>018-020-022>027-032>034.
MI...WIND ADVISORY FROM 7 AM TO 5 PM EST MONDAY FOR MIZ077>081.
OH...WIND ADVISORY FROM 7 AM TO 5 PM EST MONDAY FOR OHZ001-002-004-
005-015-016-024-025.
LM...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR LMZ043-046.
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR
LMZ043-046.
SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LMZ043-046.
&&
$$
SHORT TERM...JC
LONG TERM...MARSILI
AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1131 AM EST SAT JAN 21 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...LOW PRESSURE ACROSS EASTERN KENTUCKY AND TENNESSEE WILL
MOVE ON TO THE EAST AS HIGH PRESSURE OVER WISCONSIN MOVES EAST
ACROSS THE GREAT LAKES LATER TODAY. AN UPPER TROUGH OVER THE WEST
COAST WILL MOVE INTO THE MID MISSISSIPPI VALLEY BY SUNDAY NIGHT AND
ACROSS THE GREAT LAKES MONDAY AND MONDAY NIGHT. IN THE EXTENDED
MODELS INDICATE A ZONAL FLOW OVER THE CENTRAL AND NORTHERN U.S.
WHICH KEEPS THE ARCTIC AIR BOTTLED UP WELL TO THE NORTH AND CAUSES
OUR TEMPERATURES TO BE QUITE MILD FOR THIS TIME OF THE YEAR. AN
UPPER TROUGH IN THE SOUTHERN STREAM WILL BRING A CHANCE OF RAIN NEXT
WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /REST OF TODAY/...
CURRENT SATELLITE DEPICTS CLEARING MOVING INTO THE NW COUNTIES A
LITTLE QUICKER THAN EXPECTED. THE RUC 925-850 MB RELATIVE HUMIDITY
FIELD APPEARS TO HAVE A GOOD HANDLE ON THIS WITH A GRADUAL
CLEARING/DECREASE IN CLOUDS ACROSS THE ENTIRE CWA THROUGHOUT THE
AFTERNOON. MODEL SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
INVERSION ACROSS THE SOUTHEASTERN CWA THROUGH AT LEAST 18Z THEN
EXTENSIVE DRYING OF THE COLUMN THIS AFTERNOON. THEREFORE...CUT SKY
GRIDS SIGNIFICANTLY ACROSS THE NORTHWEST FOR LATE THIS MORNING
WITH THE TREND SHIFTING SOUTHEAST THROUGHOUT THE AFTERNOON.
OTHER THAN THAT...CURRENT FORECAST IN GREAT SHAPE WITH ONLY MINOR
TWEAKS TO HOURLY TEMPERATURES AND WINDS TO MATCH UP WITH CURRENT
TRENDS. UPDATED GRIDS AND ZONES ALREADY SENT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
FORECAST FOCUS WILL BE ON SKY COVER NEXT FEW DAYS AND RAIN CHANCES
TOWARDS THE END OF THE WEEKEND AS THE NEXT UPPER TROUGH APPROACHES.
MODELS BEGIN INCREASING LOW LEVEL MOISTURE LATER TODAY AS LOW LEVEL
FLOW BECOMES MORE SOUTHEAST AND THEN SOUTHERLY BY SUNDAY. THIS
WILL CAUSE CLOUDS TO INCREASE AGAIN BY SUNDAY. SOME CLEARING COULD
OCCUR ACROSS OUR NORTH FOR A WHILE TONIGHT AND IF IT DOES THE BOTTOM
COULD DROP ON THE TEMPERATURES WITH SNOW COVER. OTHERWISE...WILL GO
NEAR OR SLIGHTLY ABOVE MOS NUMBERS TONIGHT.
MODELS INDICATE AN INCREASING SOUTHERLY FLOW ON SUNDAY AND THIS WILL
OFTEN BREAK THE LOW LEVEL INVERSION. IF IT DOES TEMPERATURES MAY
BECOME BE A LITTLE WARMER SUNDAY. HOWEVER WITH CLOUDS BEING THE
RULE WILL GO WITH A MOS BLEND ON TEMPERATURES. WILL CONTINUE A 20
PERCENT CHANCE OF SHOWERS LATE SUNDAY AND THEN HIGH POPS ALL AREAS
SUNDAY NIGHT AS COLD FRONT APPROACHES BY MONDAY MORNING. HOURLY
TEMPERATURES MAY RISE SUNDAY NIGHT AND THEN FALL MONDAY AFTER COLD
FRONT MOVES THROUGH.
SPC HAS US IN A GENERAL RISK OF THUNDERSTORMS SUNDAY NIGHT AND EVEN
A SLIGHT RISK UP TO OUR FAR SOUTHWEST. CAPES ARE VERY
MARGINAL...BUT THERE IS A STRONG LOW LEVEL FLOW. WILL MENTION
SCATTERED THUNDERSTORMS SOUTH AND ISOLATED THUNDERSTORMS ELSEWHERE
SUNDAY NIGHT.
PRECIPITATION GRADUALLY ENDING MONDAY AFTER COLD FRONT MOVES
THROUGH. MODELS THICKNESS INDICATE A BRIEF PERIOD OF MIXED PRECIP
COULD OCCUR NORTH AND CENTRAL SECTIONS MONDAY. FINALLY DRY WEATHER
WILL BE THE RULE MONDAY NIGHT AS HIGH PRESSURE BUILDS IN FROM THE
WEST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ENSEMBLES ARE SUGGESTING AN ACTIVE SPLIT FLOW TYPE PATTERN
DEVELOPING IN THE EXTENDED. APPEARS THE MAIN ITEM OF INTEREST WILL
BE WHAT HAPPENS TO A CUTOFF LOW THAT DEVELOPS OVER THE SOUTHWEST
PARTS OF THE COUNTRY EARLY NEXT WEEK AND HOW IT MAY INTERACT WITH
THE NORTHERN STREAM. THERE IS CONSIDERABLE SPREAD AMONG THE
INDIVIDUAL MEMBERS AS TO WHEN OR EVEN IF THIS SYSTEM GETS PICKED UP
BY THE NORTHERN STREAM. AT THIS POINT...ENSEMBLE DATA INDICATE AT
LEAST SOME THREAT FOR PRECIPITATION FROM ABOUT WEDNESDAY ON. WILL GO
WITH CHANCE POPS FOR THE WEDNESDAY THROUGH FRIDAY PERIODS. AT THIS
TIME...THERE ARE STILL ONLY A COUPLE OF MEMBERS INDICATING POTENTIAL
FOR SNOW...SO WILL CONTINUE TO KEEP MAJORITY OF PRECIPITATION TYPE
AS RAIN.
&&
.AVIATION /DISCUSSION FOR THE 211800Z TAFS/...
MVFR THIS AFTERNOON...VFR THIS EVENING...THEN MVFR OVERNIGHT INTO
SUNDAY.
STUBBORN MVFR CLOUDS LOOK TO GRADUALLY ERODE FROM THE NORTHEAST
DURING THE AFTERNOON HOURS. THERE IS STILL A CHANCE THAT THEY COULD
GET TRAPPED BELOW AN INVERSION AND HANG ON INTO THE EVENING...BUT
NOT CONFIDENT OF THAT SCENARIO.
IT NOW APPEARS THAT LOW LEVEL MOISTURE WILL RETURN TO THE AREA
OVERNIGHT AS WINDS BECOME SOUTHEAST. WINDS ALOFT WILL INCREASE FROM
THE SOUTH ALSO BRINGING A RETURN OF MOISTURE. WILL BRING BACK MVFR
CEILINGS BELOW BKN020 AFTER 08Z OR SO FROM SOUTH TO NORTH.
WITH THE WARM AIR RETURNING OVER THE COLD GROUND CANNOT RULE OUT
SOME FOG OR EVEN FREEZING DRIZZLE LATE TONIGHT INTO SUNDAY
MORNING...BUT CONFIDENCE NOT HIGH ENOUGH TO PUT IN TAF YET.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...HOMANN/MK
SHORT TERM...JH
LONG TERM...JS
AVIATION...50
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1107 AM EST SAT JAN 21 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...LOW PRESSURE ACROSS EASTERN KENTUCKY AND TENNESSEE WILL
MOVE ON TO THE EAST AS HIGH PRESSURE OVER WISCONSIN MOVES EAST
ACROSS THE GREAT LAKES LATER TODAY. AN UPPER TROUGH OVER THE WEST
COAST WILL MOVE INTO THE MID MISSISSIPPI VALLEY BY SUNDAY NIGHT AND
ACROSS THE GREAT LAKES MONDAY AND MONDAY NIGHT. IN THE EXTENDED
MODELS INDICATE A ZONAL FLOW OVER THE CENTRAL AND NORTHERN U.S.
WHICH KEEPS THE ARCTIC AIR BOTTLED UP WELL TO THE NORTH AND CAUSES
OUR TEMPERATURES TO BE QUITE MILD FOR THIS TIME OF THE YEAR. AN
UPPER TROUGH IN THE SOUTHERN STREAM WILL BRING A CHANCE OF RAIN NEXT
WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /REST OF TODAY/...
CURRENT SATELLITE DEPICTS CLEARING MOVING INTO THE NW COUNTIES A
LITTLE QUICKER THAN EXPECTED. THE RUC 925-850 MB RELATIVE HUMIDITY
FIELD APPEARS TO HAVE A GOOD HANDLE ON THIS WITH A GRADUAL
CLEARING/DECREASE IN CLOUDS ACROSS THE ENTIRE CWA THROUGHOUT THE
AFTERNOON. MODEL SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
INVERSION ACROSS THE SOUTHEASTERN CWA THROUGH AT LEAST 18Z THEN
EXTENSIVE DRYING OF THE COLUMN THIS AFTERNOON. THEREFORE...CUT SKY
GRIDS SIGNIFICANTLY ACROSS THE NORTHWEST FOR LATE THIS MORNING
WITH THE TREND SHIFTING SOUTHEAST THROUGHOUT THE AFTERNOON.
OTHER THAN THAT...CURRENT FORECAST IN GREAT SHAPE WITH ONLY MINOR
TWEAKS TO HOURLY TEMPERATURES AND WINDS TO MATCH UP WITH CURRENT
TRENDS. UPDATED GRIDS AND ZONES ALREADY SENT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
FORECAST FOCUS WILL BE ON SKY COVER NEXT FEW DAYS AND RAIN CHANCES
TOWARDS THE END OF THE WEEKEND AS THE NEXT UPPER TROUGH APPROACHES.
MODELS BEGIN INCREASING LOW LEVEL MOISTURE LATER TODAY AS LOW LEVEL
FLOW BECOMES MORE SOUTHEAST AND THEN SOUTHERLY BY SUNDAY. THIS
WILL CAUSE CLOUDS TO INCREASE AGAIN BY SUNDAY. SOME CLEARING COULD
OCCUR ACROSS OUR NORTH FOR A WHILE TONIGHT AND IF IT DOES THE BOTTOM
COULD DROP ON THE TEMPERATURES WITH SNOW COVER. OTHERWISE...WILL GO
NEAR OR SLIGHTLY ABOVE MOS NUMBERS TONIGHT.
MODELS INDICATE AN INCREASING SOUTHERLY FLOW ON SUNDAY AND THIS WILL
OFTEN BREAK THE LOW LEVEL INVERSION. IF IT DOES TEMPERATURES MAY
BECOME BE A LITTLE WARMER SUNDAY. HOWEVER WITH CLOUDS BEING THE
RULE WILL GO WITH A MOS BLEND ON TEMPERATURES. WILL CONTINUE A 20
PERCENT CHANCE OF SHOWERS LATE SUNDAY AND THEN HIGH POPS ALL AREAS
SUNDAY NIGHT AS COLD FRONT APPROACHES BY MONDAY MORNING. HOURLY
TEMPERATURES MAY RISE SUNDAY NIGHT AND THEN FALL MONDAY AFTER COLD
FRONT MOVES THROUGH.
SPC HAS US IN A GENERAL RISK OF THUNDERSTORMS SUNDAY NIGHT AND EVEN
A SLIGHT RISK UP TO OUR FAR SOUTHWEST. CAPES ARE VERY
MARGINAL...BUT THERE IS A STRONG LOW LEVEL FLOW. WILL MENTION
SCATTERED THUNDERSTORMS SOUTH AND ISOLATED THUNDERSTORMS ELSEWHERE
SUNDAY NIGHT.
PRECIPITATION GRADUALLY ENDING MONDAY AFTER COLD FRONT MOVES
THROUGH. MODELS THICKNESS INDICATE A BRIEF PERIOD OF MIXED PRECIP
COULD OCCUR NORTH AND CENTRAL SECTIONS MONDAY. FINALLY DRY WEATHER
WILL BE THE RULE MONDAY NIGHT AS HIGH PRESSURE BUILDS IN FROM THE
WEST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ENSEMBLES ARE SUGGESTING AN ACTIVE SPLIT FLOW TYPE PATTERN
DEVELOPING IN THE EXTENDED. APPEARS THE MAIN ITEM OF INTEREST WILL
BE WHAT HAPPENS TO A CUTOFF LOW THAT DEVELOPS OVER THE SOUTHWEST
PARTS OF THE COUNTRY EARLY NEXT WEEK AND HOW IT MAY INTERACT WITH
THE NORTHERN STREAM. THERE IS CONSIDERABLE SPREAD AMONG THE
INDIVIDUAL MEMBERS AS TO WHEN OR EVEN IF THIS SYSTEM GETS PICKED UP
BY THE NORTHERN STREAM. AT THIS POINT...ENSEMBLE DATA INDICATE AT
LEAST SOME THREAT FOR PRECIPITATION FROM ABOUT WEDNESDAY ON. WILL GO
WITH CHANCE POPS FOR THE WEDNESDAY THROUGH FRIDAY PERIODS. AT THIS
TIME...THERE ARE STILL ONLY A COUPLE OF MEMBERS INDICATING POTENTIAL
FOR SNOW...SO WILL CONTINUE TO KEEP MAJORITY OF PRECIPITATION TYPE
AS RAIN.
&&
.AVIATION /DISCUSSION FOR THE 211430Z TAF UPDATE/...
UPDATE...AREA OF MVFR CEILINGS ACROSS OH HAS WORKED SOUTHWEST INTO
CENTRAL INDIANA. THESE CLOUDS LOOK TO PERSIST FOR AT LEAST A FEW
HOURS BEFORE BREAKING UP/MOVING OUT. THUS HAVE KEPT MVFR CEILINGS
LONGER AT KIND.
PREVIOUS DISCUSSION...
BACK EDGE OF VFR CEILINGS AROUND 050 PROGRESSING SOUTH ACROSS
NORTHERN INDIANA. MODEL DATA SUGGEST DRIER AIR WILL BE WORKING IN
FROM THE NORTH TODAY...SO EXPECT THIS TREND TO CONTINUE...WITH
CEILINGS SCATTERING OUT FROM NORTH TO SOUTH FROM LATE THIS MORNING
INTO THE AFTERNOON HOURS. STILL SOME POCKETS OF MVFR CEILINGS
AROUND 020...SO THESE LOWER CEILINGS WILL PROBABLY IMPACT THE TAF
SITES FROM TIME TO TIME THROUGH LATE THIS MORNING.
MAY SEE OCCASIONAL SURFACE WIND GUSTS 15-18KTS FROM 010-030 HEADINGS
THROUGH MIDDAY AS PRESSURE RISE MAX MOVES THROUGH.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...HOMANN/MK
SHORT TERM...JH
LONG TERM...JS
AVIATION...JAS/50
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1228 AM EST SAT JAN 21 2012
.AVIATION...
BACK EDGE OF AREA OF SNOW MOVG EAST ACROSS NRN INDIANA ATTM AND SHOULD
CLEAR FWA IN NEXT COUPLE OF HOURS WITH VFR CONDITIONS UPSTREAM
OVER SW MI/NW INDIANA FOLLOWING THE END OF THE SNOW OVERNIGHT. VFR
CONDITIONS SHOULD PERSIST DURING THE DAY AND INTO TONIGHT AS HIGH
PRESSURE RIDGE MOVES ACROSS THE AREA.
&&
.PREV DISCUSSION...
UPDATE...
SNOW EVENT EVOLVING AS EXPECTED SO FAR. UPSTREAM REPORTS IN NORTHERN
IL INDICATE EXPECTED POTENTIAL FOR SOME AMOUNTS NEAR OR JUST ABOVE 6
INCHES. CURRENT ADVISORY HAS THIS WELL IN HAND WITH WORDING SO
CURRENTLY NO PLANS TO UPGRADE HEADLINES UNLESS WE START GETTING
WIDESPREAD REPORTS IN EXCESS OF 6 TO 7 INCHES LATER THIS EVENING
WITH ADDITIONAL SNOWFALL EXPECTED. MOST REPORTS SO FAR IN THE 1 TO 3
INCH RANGE WITH A FEW EXCEPTIONS. VISIBILITIES BEGINNING TO RISE
SLOWLY NEAR AND WEST OF CHICAGO SO EXPECT OUR WESTERN AREAS TO SEE
THIS MODERATE TO BRIEFLY HEAVY SNOW FOR A FEW MORE HOURS BEFORE
SNOWFALL RATES GRADUALLY DECREASE THERE WITH PROGRESSION EAST
THROUGH THE LATE EVENING AND OVERNIGHT HOURS. HIGH RES GUIDANCE ALSO
SHOWING THIS WITH HRRR LOOKING VERY GOOD SO FAR.
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
MAIN FORECAST FOCUS WILL CONTINUE TO CENTER ON SIGNIFICANT SNOW
ACCUMULATIONS TONIGHT. A WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT FOR THE ENTIRE FORECAST AREA THROUGH 12Z SATURDAY.
A ZONE OF STRONG ISENTROPIC UPGLIDE PER RUC/GFS 290K SFC WILL
CONTINUE TO LIFT NORTHEAST ACROSS NORTHERN PORTIONS OF THE FORECAST
AREA. SEVERAL REPORTS NOW OF 1/2 TO 1/4 MILE VSBYS ACROSS NORTHERN
ILLINOIS AND STRONGEST ISENTROPIC ASCENT SHOULD SHIFT EASTWARD
ACROSS NORTHERN INDIANA/SOUTHERN LOWER MICHIGAN IN THE 22Z-03Z
TIMEFRAME. DURING THIS PERIOD OF STRONGER FORCING...STRONGEST UPWARD
VERTICAL MOTION SHOULD BE SOLIDLY ENCOMPASSED IN FAVORABLE DENDRITIC
GROWTH ZONE. THUS...SHOULD SEE A PERIOD EARLY THIS EVENING WHERE
SNOW TO LIQUID RATIOS INCREASE SHARPLY FOR A TIME. ISENTROPIC PROGS
HAVE ALSO SUGGESTED PERHAPS A SLIGHT WEAKENING OF THE ISENTROPIC
LIFT THIS EVENING AS VORT MAX SKIRTING ACROSS SOUTHERN WISCONSIN
THIS AFTERNOON BECOMES MORE SHEARED ACROSS THE SOUTHERN LAKES.
NONETHELESS...A 2 TO 4 PERIOD OF SNOWFALL RATES AROUND AN INCH PER
HOUR APPEARS TO BE POSSIBLE LATE THIS AFTERNOON/EARLY THIS EVENING
FOR AREAS ESPECIALLY ALONG AND NORTH OF THE ROUTE 30 CORRIDOR.
ACCUMULATIONS WILL BE IN SOMEWHAT MORE QUESTION ACROSS THE SOUTH AS
THIS BAND SHOULD PROVIDE GREAT IMPACTS ACROSS THE NORTHERN HALF.
WATER VAPOR IMAGERY CONTINUES TO INDICATE A STRONGER VORT MAX
DROPPING INTO THE CENTRAL PLAINS THAT WILL BEGIN TO SHIFT EASTWARD
INTO THE MID MS RVR VALLEY LATER THIS EVENING. SHOULD START TO SEE A
MORE FRONTALLY FORCED AREA OF SNOW DEVELOP EXTENDING SOUTHWEST FROM
THIS INITIALLY WEST TO EAST ORIENTED BAND THAT WILL AFFECT
CENTRAL/SOUTHERN AREAS LATE THIS EVENING. STILL EXPECTING STORM
TOTAL SNOWFALL AMOUNTS IN THE 4 TO 7 RANGE CENTRAL AND NORTH...WITH
AMOUNTS IN THE 2 TO 4 RANGE FAR SOUTH. GFS/RUC VERTICAL CROSS
SECTIONS ALSO INDICATE INCREASING INSTABILITY ALOFT (NEGATIVE EPV)
LIFTING ACROSS EASTERN SECTIONS OF THE AREA LATE THIS EVENING AS
SOUTHWESTERLY FLOW STRENGTHENS IN ADVANCE OF THIS SECONDARY SHORT
WAVE. THIS INCREASE IN INSTABILITY ALOFT SHOULD CORRESPOND TO THIS
SECONDARY MID LEVEL FORCING MAX WITH THIS SHORT WAVE...SO HAVE
KEPT AMOUNTS MORE SOLIDLY IN THE ADVISORY RANGE IN THE FAR
SOUTHEAST...WITH SLIGHTLY LESSER TOTALS IN THE SOUTHWEST.
CURRENTLY HAVE DRAWN UP TOTAL ACCUMULATIONS JUST BELOW ADVISORY
CRITERIA ACROSS THE SOUTHWEST BUT DUE TO COMPLICATING MESOSCALE
FORCING MECHANISMS MENTIONED...WILL MAINTAIN ALL HEADLINES AT THIS
TIME.
CONDITIONS TO IMPROVE FROM WEST TO EAST OVERNIGHT WITH THE PASSAGE
OF THIS SECONDARY VORT MAX. ORIENTATION OF RIDGE AXIS TO THE WEST
SHOULD SUPPORT ANY LAKE EFFECT SNOW SHOWERS WEST OF THE LOCAL
FORECAST AREA INTO NORTHWEST INDIANA/NORTHEAST ILLINOIS. SATURDAY
SHOULD FEATURE QUIET WEATHER WITH SFC HIGH BEGINNING TO BUILD IN.
WEAK LOW LEVEL EASTERLIES AND NEW SNOW COVER SHOULD PROMOTE WEAK
MIXING AND HAVE UNDERCUT MOST AVAILABLE GUIDANCE FOR HIGH TEMPS.
LONG TERM...
SUNDAY THROUGH FRIDAY
MID LEVEL FLOW TRANSITION STILL ON TRACK IN THE PERIOD GIVEN THE
RETURN OF ALASKA TROUGHING...WITH MUCH MILDER PAC ORIGIN DOWNSLOPE
FLOW EXPECTED INTO THE REGION BY EARLY NEXT WEEK. A DEEP LONGWAVE
TROUGH IS STILL EXPECTED IN THE SUN NIGHT-MON PERIOD...SUPPORTING
ROBUST LL FLOW FIELDS WITH SIG THETA-E ADVECTION INTO THE AREA.
SPLIT FLOW REGIME WILL FOLLOW WITH STRONG MODEL/ENSEMBLE SUPPORT
CONTINUING. FAST PERTURBED WNW FLOW WILL OFFER LOW CONFIDENCE PER
DISTURBANCE TIMING IN THE LATE PERIODS GIVEN TYPICAL POOR MODEL
PERFORMANCE PER THESE FEATURES. HENCE...NO SIG CHANGE PER PRECIP
CHANCE WED-FRI...WITH PREFERENCE TOWARD 24-36 HOUR FORECAST WINDOWS
PER PRECIP CHANCES GIVEN INHERENT VARIABILITY PER IMPULSE TIMING.
SUN-MON...SIG MID LEVEL TROUGH IS STILL ON TRACK TO DIG INTO THE SW
CONUS AND BEGIN TO EJECT TOWARD THE REGION. ECMWF/GEM/UKMET ARE
PREFERRED GIVEN THEIR HANDLING OF THE DIGGING MID LEVEL TROUGH WITH
NEGATIVE TILT CHARACTERISTICS. CERTAINLY DONT BUY THE NAM/S OUTLIER
NORTH BIAS PER THE SFC CYCLONE AND THE GFS/S WILD VARIABILITY PER
TROUGH DEPTH/TIMING/AND TRACK. CONTINUED MODEL SUPPORT FOR A STRONG
SOUTHERN PERIPHERY UPPER JET STREAK AND NEGATIVE UPPER TROUGH TILT
SUGGESTS A WEST BIAS TO THE SFC LOW TRACK WITH SLOWER SYSTEM ARRIVAL
AND HAVE CONTINUED THIS IN THE GRIDS. SYSTEM INFLUENCE TO THE LOCAL
AREA WILL BEGIN ON SUNDAY...WITH REFLECTED LL SOUTHERLY FLOW
INCREASING THROUGH THE SUNDAY DAY PERIOD. LINGERING BAROCLINIC ZONE
IN PLACE OVER THE CENTRAL PLAINS WILL INTERACT WITH THE EJECTING MID
LEVEL DISTURBANCE TO SUPPORT ROBUST SFC PRESSURE FALLS...SUPPORTING
RAPID SFC CYCLOGENESIS. THIS WILL ALLOW SIG LL THETA-E ADV TO ENSUE
LATE SUNDAY IN THE REGION WITH SIG SFC LAYER DEWPOINT RISES BY
SUNDAY NIGHT. STAUNCH LL FLOW WITH A 60 TO 70 KNOT LLJ PROGGED IN
THE ECMWF...WILL BE MORE THAN ENOUGH TO SUPPORT DEEP LAYER THETA-E
RISES. SNOWPACK IN PLACE WILL LIKELY SUPPORT A SATURATED BL WITH
DRIZZLE AND FOG EXPECTED TO DEVELOP LATE SUNDAY AFTERNOON /AT THE
EARLIEST/ INTO THE EVENING...LIKELY PERSISTING THROUGH SUNDAY NIGHT.
ECMWF H7-H3 LAYER ANALYSIS CONTINUES TO INDICATE AN INTACT EML WITH
STEEP MID LEVEL LAPSE RATES GIVEN STRONG LOW CENTERED WAA. H85
THETA-E APPROACHES 325K BY LATE SUNDAY NIGHT...WITH SW INDICES
NEGATIVE...INDICATING A GOOD ENVIRONMENT FOR ELEVATED THUNDERSTORMS.
HAVE MAINTAINED A LOW CHANCE THUNDER AT THIS POINT. ALBEIT
SMALL...THERE REMAINS A SMALL CONCERN FOR SEVERE WEATHER GIVEN
INDICATED H5 JETLET IN EXCESS OF 85 KNOTS...WHICH WOULD BE CAPABLE
OF SUPPORTING A QLCS JET DRIVEN THIN LINE. CONCERNS FOR INCREASED
FLOODING CONTINUE GIVEN FULL SNOWPACK MELT WITH THE POTENTIAL FOR
HEAVY RAIN. IN ADDITION...A SLOWER TROUGH ARRIVAL PER NEGATIVE
TROUGH TENDENCIES WOULD SUPPORT HIGHS INTO THE 50S AKIN TO ECMWF
PROGS. CAA WILL DOMINATE MONDAY WITH FALLING TEMPS IN THE DAYTIME
PERIOD LIKELY. LINGERING LIGHT SNOW SHOWERS WILL BE POSSIBLE.
TUE-FRI...FAST WNW PAC ORIGIN FLOW IS EXPECTED INTO THE REGION WITH
ROCKIES ENHANCED IMPULSES EXPECTED. STRONGEST PROGGED IMPULSE
REMAINS IN THE WED-THUR PERIOD AND HAVE RETAINED POPS THEN...OPTING
TO KEEP THE RAIN/SNOW WORDING GIVEN WARM THERMAL FIELDS. HAVE ALSO
EXTENDED THIS MENTION INTO FRIDAY MAINLY PER COLLAB WITH SURROUNDING
OFFICES...WHICH ALSO FITS THE ACTIVE PATTERN. OTHERWISE...ADJUSTED
TEMPS UP SOME...WITH ABOVE NORMAL TEMPS LIKELY ONCE AGAIN.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ THIS MORNING
FOR INZ003>009-012>018-020-022>027-032>034.
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR
MIZ077>081.
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR OHZ001-
002-004-005-015-016-024-025.
LM...NONE.
&&
$$
SHORT TERM...MARSILI
LONG TERM...JC
AVIATION...JT
UPDATE...LASHLEY
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1212 PM CST SAT JAN 21 2012
.AVIATION...
CLOUD TRENDS BIGGEST CHALLENGE WITH 18Z TAFS. STRATUS WITH
MVFR CIGS CONTINUES TO BLANKET THE REGION EARLY THIS AFTN. THE
CLEARING THAT HAD WORKED INTO KDBQ FROM THE NORTH HAS SINCE
STALLED AND RETREATED BACK NWD WITH ONSET OF LLVL WARM
ADVECTION AND E/SE WINDS SFC-925 MB. SATL SHOWS WEDGE OF
CLEARING INTO CENTRAL IL WITH REGION OF DRY AIR AT 925 MB.
AS THE FLOW CONTINUES TO VEER TO E/SE THERE IS POTENTIAL
FOR THIS DRIER AIR AND CLEARING TO OVERSPREAD THE
TERMINALS... MAINLY KBRL AND POSSIBLY KMLI AND KDBQ... LATE
AFTN THROUGH THIS EVE. LATEST HRRR MODEL CAPTURES CURRENT
CLEARING TRENDS FAIRLY WELL AND DEPICTS CLEARING INTO PORTIONS OF
EASTERN IA... AND SO HAVE INTRODUCED AT KBRL WHERE CONFIDENCE
IS GREATEST AND TEMPO AT KMLI THIS EVE... BUT LEFT OUT AT KDBQ.
WILL JUST HAVE TO WATCH CLOUD TRENDS AND AMEND AS TRENDS BECOME
BETTER IDENTIFIED. ANY CLEARING LIKELY TO BE SOMEWHAT SHORTLIVED
WITH LOW CLOUDS AND MAINLY MVFR CIGS REDEVELOPING OVRNGT INTO
SUN AM WITH STRENGTHENING LOW LEVEL WARM...MOIST ADVECTION. THERE
IS WINDOW OF LLWS POTENTIAL LATE EVE INTO EARLY OVRNGT AND HAVE
ADDED MENTION IN TAFS... AS WINDS AROUND 2000 FT AGL INCREASE FROM
S/SE TO 40-45 KTS WHILE SFC WINDS GENERALLY E/SE 10-15KTS WITH
SOME GUSTS POSSIBLE. FEW FLURRIES EXPECTED BENEATH STRATUS WITH
ANY LINGERING PCPN LIKELY TRANSITIONING TO FREEZING DRIZZLE AS TEMPS
WARM JUST ABOVE AND LOSE ICE INTRODUCTION. LOW CONFIDENCE ON
COVERAGE PRECLUDES MENTION ATTIM.
&&
.PREV DISCUSSION... /ISSUED 330 AM CST SAT JAN 21 2012/
SYNOPSIS...
LATEST SFC ANALYSIS WAS INDICATING HIGH PRESSURE COMPLEX OCCUPYING
MUCH OF THE UPPER MS RVR VALLEY...DOWN INTO THE CENTRAL PLAINS
WITH LARGE PRESSURE RISES NOTED TO THE LEE OF IT ACRS SOUTHEAST WI
INTO EASTERN OK ATTM. LLVL STRATUS DECK ON ITS EASTERN AND SOUTHERN
FLANK SHOWING LITTLE SIGNS OF WANTING TO BUDGE SOUTHWARD. ALOFT...
WATER VAPOR IMAGERY AND 00Z UA ANALYSIS WERE INDICATING THAT WHILE
L/W TROFFINESS WAS STARTING TO EXIT THE REGION TO THE EAST...BROAD
UPPER RIDGING WAS SLIDING ACRS THE PLAINS. FURTHER UPSTREAM...W/V
IMAGERY WAS INDICATING YET ANOTHER LARGE SLUG OF UPPER WAVE ENERGY
PUMMELING ITS WAY INTO THE WEST COAST.
SHORT TERM...TODAY AND TONIGHT...
TODAY...BACKING ELEVATED FLOW TO WARM AIR ADVECT BIG TIME TODAY
IN THE H8-H7 MB LAYER THROUGH THIS EVENING. THE SFC RIDGE CENTER
MENTIONED ABOVE WILL LOOK TO MIGRATE TO EASTERN LOWER MI BY LATE
AFTERNOON WITH SFC WINDS VEERING TO AN EAST TO SOUTHEASTERLY SFC
COMPONENT AS THE DAY PROGRESSES. SFC WINDS OF 5 TO 8 MPH PRODUCING
NEAR ADVISORY LEVEL WIND CHILLS IN THE EXTREME NORTHWEST PORTION OF
THE DVN CWA ATTM IN AREA OF SOME CLEARING...BUT NOT WIDESPREAD
ENOUGH OR TO LAST LONG ENOUGH TO WARRANT AN ADVISORY WITH THE
LIGHTER WIND REGIME IN VCNTY OF IN-BUILDING RIDGE. FEEL THE SHORT
RANGE MODELS NOT HANDLING THE LLVL STRATUS ALL THAT WELL AND THAT IT
MAY REMAIN TRAPPED UNDER THE BUILDING INVERSION FOR MUCH OF THE DAY
ESPECIALLY ACRS THE SOUTHERN HALF TO TWO THIRDS OF THE DVN CWA.
WILL SLOW THE CLEARING AN MAY KEEP MUCH OF THE CWA MOSTLY CLOUDY
INTO AT LEAST EARLY AFTERNOON. AREAS NORTH OF I80 SHOULD HAVE THE
BEST CHANCE OF CLEARING THIS AFTERNOON WITH SOME DIURNAL MIXING IN
THINNER CLOUD LAYER. WITH THE CLOUDS...WILL LEAN TOWARD THE COLDER
SIDE OF GUIDANCE HIGHS AS THE WARMING MORE REALIZED ALOFT. SOME
AREAS NOT RECOVERING MUCH WARMER THAN WHERE THEY ARE AT NOW. AREAS
THAT HAVE THE BEST CHANCE OF CLEARING ALSO HAVE THE DEEPER SNOW
COVER THUS COULD LIMIT THE HIGHS EVEN IN THOSE AREAS.
TONIGHT...EVEN IF CLOUDS CLEAR OUT IN MUCH OF THE CWA FOR A PERIOD
LATE THIS AFTERNOON AND INTO THE EVENING...EXPECT INCREASING RETURN
FLOW/WAA REGIME TO SLOSH BACK LOW CLOUDS UNDER THE INVERSION OR SET
UP A SITUATION WHERE THE LOW DECK WILL REFORM AS THE NIGHT PROGRESSES.
FCST SOUNDINGS SHOW A POTENTIAL DRIZZLE SCENARIO IN AT LEAST THE
SOUTH HALF OF THE DVN CWA AFTER 08Z SUNDAY AS BOUNDARY LAYER
MOISTURE TRAPPED UNDER THE INVERSION IN A TEMP PROFILE OF 0 TO -5C
INCREASES ENOUGH TO A DEPTH TO SUPPORT VERY LIGHT PRECIP AND THE
DRY MILDER LAYER ALOFT REMAINS AT DEEP ENOUGH WEDGE TO PREVENT
SEEDER FEEDERS. POS OMEGAS/LIFT THROUGH PART OF THE COLUMN ENOUGH
TO INDUCE SOME LIGHT PRECIP TO ALSO COMMENCE LATE TONIGHT FROM
THE WEST. ALTHOUGH EXPECT NIGHT TIME LOWS TO OCCUR DURING THE MID
EVENING WITH STEADY TO SLOWLY RISING TEMPS AFTER THAT INTO SUNDAY
MORNING...SFC TEMPS PROBABLY NOT TO RECOVER ABOVE FREEZING WHERE
THE DRIZZLE BREAKS OUT SO WILL ADD PATCHY FREEZING DRIZZLE FOR NOW
ALONG AND SOUTH OF THE I80 CORRIDOR. THINK MIXING SOUTHEAST SFC
WINDS WILL BE STRONG ENOUGH AFTER MIDNIGHT OF 10-15+ KTS...AS WELL
AS SFC DPTS NOT HIGH ENOUGH TO FOSTER WIDESPREAD DENSE FOG
DEVELOPMENT AND WILL KEEP OUT MENTION FOR NOW. ..12..
LONG TERM...SUNDAY THROUGH FRIDAY...
THE MODEL SOLUTIONS ARE COMING INTO BETTER AGREEMENT WITH THE LATE
WEEKEND SYSTEM. A POTENT S/W JUST OFF THE NORTHERN CA COAST EARLY
THIS MORNING WILL MOVE THROUGH THE WESTERN U.S. TODAY AND TONIGHT
THEN SWING NORTHEAST REACHING THE WESTERN GREAT LAKES BY LATE MONDAY.
THERE WILL BE A GOOD FEED OF GULF MOISTURE AHEAD OF THE SYSTEM...BUT
MODEL SOLUTIONS SHOW THE BULK OF THE LOW LEVEL MOIST FEED BEING
DEFLECTED TO OUR EAST AND NORTH. THE ECMWF WITH IT/S DEEPER AND
SLOWER SOLUTION PULLS SOME OF THE MOISTURE/PRECIP BACK INTO THE
EASTERN HALF OF THE CWFA. SUNDAY NIGHT AND MONDAY MORNING.
FOR SUNDAY AND SUNDAY NIGHT SOUTHERLY LOW LEVEL FLOW OVER THE NEW
SNOWPACK RAISES THE POTENTIAL FOR STRATUS/DRIZZLE...ESPECIALLY
WITH THE MID LEVELS REMAIN DRY MOST OF THE SUNDAY. INTRODUCED SOME
PATCHY DRIZZLE FOR THE LATE MORNING AND AFTERNOON HOURS OVER MUCH
OF THE AREA. TEMPERATURES OVER THE NORTHERN THIRD OF THE FORECAST
AREA...WHERE THE DEEPER SNOW IS...WILL LIKELY STAY BELOW FREEZING
UNTIL SUNDAY AFTERNOON...SO MENTIONED PATCHY FREEZING DRIZZLE IN
THE NORTH SUNDAY MORNING. CHANCE WEST TO LIKELY POPS EAST WERE
MAINTAINED FOR SUNDAY NIGHT WITH THE UPPER TROF AXIS LIFTING
THROUGH AND DEEPER MOISTURE MOVING IN. THIS SHOULD BE A RAIN
CHANGING TO SNOW SCENARIO FOR SUNDAY NIGHT AS COLDER AIR MOVES IN.
PTYPE BY LATE SUNDAY NIGHT SHOULD BE SNOW. DUE TO THE MIXED NATURE
OF THE PRECIPITATION DURING THE FIRST PART OF THE EVENT...HAVE
KEPT SNOWFALL AMOUNTS TO LESS THAN AN INCH...AND THAT SHOULD BE
OVER THE NWRN CWFA. THERE IS ALSO A LOW THREAT OF SOME FREEZING
RAIN DURING THE TRANSITION PERIOD SUNDAY EVENING ESPECIALLY IN EAST
CENTRAL IOWA.
AFTER MONDAY THE MID LEVEL FLOW BECOMES MORE ZONAL OVER THE
NORTHERN U.S. ANOTHER TROF MOVES THROUGH THE REGION TUESDAY NIGHT
AND WEDNESDAY. SO FAR THIS FEATURE APPEARS TO BE MOISTURE STARVED
AND ONLY WARRANTS LOW CHANCE POPS FOR A RAIN/SNOW MIX.
THE PREDOMINANT WEST TO EAST FLOW MID TO LATE WEEK SHOULD PREVENT
ANY INTRUSION OF THE COLD AIR OVER CANADA...RESULTING IN NEAR TO
ABOVE NORMAL TEMPERATURES. ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
500 PM CST SAT JAN 21 2012
.AVIATION...
FOR THE 00Z TAF ISSUANCE...MAIN CONCERN IN THE AVIATION WORLD IS
WINDS. FOLLOWED RECENT HRRR GUIDANCE WHICH KEEPS SOUTHERLY WINDS 15
TO 20 KT THROUGH THE OVERNIGHT. MEANWHILE, AN APPROACHING COLD FRONT
IS EXPECTED TO TRAVERSE ACROSS THE REGION BY TOMORROW MORNING. SO
WINDS WILL VEER TO THE SW THEN FINALLY TO THE NW AFTER THE FRONT
PASSES THROUGH. ALL GUIDANCE SUPPORTS STRONG WINDS SO HAVE
INCREASED WINDS IN THE 26-32KT RANGE WITH GUSTS TO 35-40KT BY AND
AFTER 15Z TOMORROW. OTHERWISE, VFR CIGS WILL PREVAIL. -SUGDEN
&&
.PREV DISCUSSION... /ISSUED 303 PM CST SAT JAN 21 2012/
DISCUSSION...
DAYS 1-2...
THE MAIN FORECAST FOCUS WILL ON THE CHANCE FOR PRECIP DURING THE
PERIOD AND TEMPERATURES.
WV IMAGERY AND 12Z UPPER AIR ANALYSIS INDICATE A WEAK UPPER LEVEL
RIDGE OF HIGH PRESSURE TRANSITIONING EAST ACROSS THE CENTRAL PLAINS.
MEANWHILE, AN UPPER LEVEL TROUGH OF LOW PRESSURE IS PUSHING ASHORE
IN NORTHERN CALIFORNIA. NEAR THE SURFACE, A LEE SIDE TROUGH OF LOW
PRESSURE PREVAILS ACROSS EASTERN COLORADO.
SHORT RANGE MODELS INDICATE THE UPPER LEVEL TROUGH PUSHING EAST
ACROSS THE FOUR CORNERS REGION TONIGHT AND INTO THE WESTERN HIGH
PLAINS SUNDAY BRINGING THE POSSIBILITY FOR PRECIP TO PORTIONS OF
WESTERN AND CENTRAL KANSAS BY SUNDAY AFTERNOON. A STRONG H5 VORT
MAX IS PROGGED TO PASS THROUGH WESTERN KANSAS BY 18Z IN CONJUNCTION
WITH A COLD FRONT ASSOCIATED WITH THE UPPER TROUGH AXIS. HOWEVER
THE STRONG JET CORE ASSOCIATED WITH THE SYSTEM WILL REMAIN JUST
OFF TO OUR SOUTH ACROSS WEST TEXAS. ADDITIONALLY, LOW LEVEL
MOISTURE WILL BE LACKING WITH H85 DEWPOINTS PROJECTED TO REMAIN
WELL BELOW 0C, NOT TO MENTION A LACK OF MID LEVEL INSTABILITY.
STILL, THE NAM, GFS, AND ECMWF SHOW INCREASED MOISTURE ADVECTION
IN THE MID LEVELS ALONG WITH A POST FRONTAL H7 BAROCLINIC ZONE
PASSING ACROSS WESTERN KANSAS SUNDAY AFTERNOON. CANNOT RULE OUT A
FEW PASSING SPRINKLES OR AN ISOLATED SHOWER OR TWO ACROSS WESTERN
AND CENTRAL KANSAS. AT THE VERY LEAST INCREASED CLOUDINESS WITH
VIRGA WILL BE POSSIBLE CONSIDERING THE DRIER LOW LEVELS. WILL
LOWER POPS DOWN TO SLIGHT CATEGORY ACROSS SOUTH CENTRAL AND
EXTREME SOUTHWEST KANSAS WHILE LEAVING LOW END CHANCE CATEGORY
POPS IN NEAR THE I-70 CORRIDOR.
TEMPERATURES WILL BE MUCH WARMER TONIGHT AS LEE SIDE TROUGHING
STRENGTHENS OVERNIGHT. THIS WILL ENHANCE WARM AIR ADVECTION INTO
WESTERN KANSAS WITHIN A LOW LEVEL SOUTHWESTERLY FLOW RAISING H85
TEMPERATURES UP TO AROUND 10C TO 12C. ADDITIONALLY, MOISTURE
ADVECTION WILL INCREASE SURFACE DEWPOINTS UP INTO THE 20S(F)
ACROSS SOUTH CENTRAL AND SOUTHWEST KANSAS. LOOK FOR LOWS MAINLY
DOWN INTO THE 30S(F) WITH THE WARMER TEMPERATURES ACROSS OUR EXTREME
SOUTHWEST WHERE DOWNSLOPING WILL BE MORE OF A FACTOR TOWARD 12Z.
FOR SUNDAY, A COLD FRONT WILL QUICKLY PUSH EAST ACROSS WESTERN
KANSAS BY LATE MORNING TURNING WINDS NORTHWESTERLY. EVEN SO,
DOWNSLOPING COMBINED WITH THE INITIAL MIXING OF WARMER AIR JUST
OFF THE DECK (H85 TEMPERATURES AROUND 10C) AS THE FRONT MOVES
THROUGH, WILL ALLOW TEMPERATURES TO CLIMB WELL UP INTO THE 40S(F)
WITH SOME LOWER TO MID 50S(F) POSSIBLE BY EARLY AFTERNOON. LOW
TEMPERATURES ARE EXPECTED TO FALL BACK BELOW FREEZING SUNDAY NIGHT
AS DECREASING WINDS AND CLOUDS ACCOMPANY A SMALL AREA OF SURFACE
HIGH PRESSURE MOVING EAST ACROSS SOUTHWEST KANSAS. AS FOR MONDAY,
LEE SIDE TROUGHING WILL QUICKLY DEVELOP ACROSS EASTERN COLORADO
HELPING TO RETURN SOUTHERLY WINDS TO WESTERN KANSAS BY MONDAY
AFTERNOON. THE NAM, GFS, AND ECMWF SHOW H85 TEMPERATURES RANGING
FROM JUST ABOVE 0C ACROSS CENTRAL KANSAS TO NEAR 5C ALONG THE
COLORADO BORDER. ALONG WITH PLENTY OF SUNSHINE, LOOK FOR HIGHS UP
INTO THE 50S(F) MONDAY.
WINDS WILL BE FAIRLY STRONG OUT OF THE NORTHWEST LATE SUNDAY MORNING
AND AFTERNOON. ALL MODELS SHOW H85-H7 WINDS AROUND 40 TO 50KT JUST
BEHIND THE FRONT. WITH SOME MIXING EXPECTED AS THE FRONT MOVES
THROUGH, WIND ADVISORY WINDS ARE EXPECTED TO BE MET. HOWEVER,
LESS CERTAINTY REMAINS AS TO WHERE A BRIEF HIGH WIND GUST MAY
OCCUR TO WARRANT A HIGH WIND WARNING. WILL DEFER TO THE NEXT SHIFT
WITH A HIGH WIND WATCH ALREADY ALERTING THE PUBLIC TO THE POTENTIAL
OF STRONGER WINDS.
DAYS 3-7...
FOR TUESDAY AN UPPER LEVEL SHORTWAVE TROUGH WILL BE GOING THROUGH
THE NORTHERN PLAINS WHILE AN UPPER CLOSED LOW CONTINUES TO DIG INTO
SOUTHERN NEW MEXICO. KANSAS WILL BE IN BETWEEN THESE TWO SYSTEMS
WITH ONLY SOME HIGH LEVEL CLOUDINESS EXPECTED. LOWS ON TUESDAY
MORNING WILL RANGE FROM THE MID TO UPPER 20S. HIGHS WILL BE IN THE
MID TO UPPER 40S, TO AROUND 50 SOUTHEAST FA AROUND MEDICINE LODGE.
FOR WEDNESDAY ANOTHER NORTHERN BRANCH WAVE MOVES ACROSS THE PLAINS
WITH WINDS SHIFTING NORTHERLY WHILE THE SOUTHERN UPPER LOW GETS
CUTOFF IN NORTHERN MEXICO. NEAR THE WIND SHIFT IN THE SOUTHEAST
AROUND MEDICINE LODGE THE DEWPOINTS RISE INTO THE MID 30S WITH A
SLIGHT CHANCE FOR RAIN EARLY WEDNESDAY MORNING. NOT MUCH CHANGE IN
THE TEMPERATURES FOR WEDNESDAY WITH MORNING LOWS IN THE UPPER 20S
NORTH TO MID 3OS SOUTHEAST. HIGHS WILL BE AROUND 50. ON THURSDAY DRY
NORTHWESTERLY FLOW CONTINUES WITH A LEE TROUGH DEVELOPING. LOWS WILL
BE AROUND 30 WITH WARMER HIGHS IN THE MID 50S. FOR FRIDAY A STRONGER
NORTHERN BRANCH SHORTWAVE TROUGH MOVE INTO THE NORTHERN AND CENTRAL
PLAINS WITH COOLER HIGH PRESSURE MOVING INTO THE PLAINS. MORNING
LOWS WILL BE IN THE LOW TO MID 30S WITH HIGH TEMPS A BIT COOLER AND
AROUND 50. ON SATURDAY THE EC MODEL HAS A DEEPER TROUGH MOVING
THROUGH THE UPPER MIDWEST IN THE MORNING, WHILE THE GFS IS FLATTER
WITH A MORE ZONAL FLOW. LOWS LOOK TO BE IN THE MID 20S NORTH TO
AROUND 30 SOUTH WITH COOLER HIGHS IN THE MID 40S.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 30 50 22 53 / 0 30 0 0
GCK 32 50 20 52 / 0 30 0 0
EHA 37 52 23 53 / 0 20 0 0
LBL 35 53 20 55 / 0 20 0 0
HYS 28 48 20 50 / 0 30 0 0
P28 28 55 25 55 / 0 20 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM CST /9 AM MST/ TO 4 PM CST /3 PM MST/
SUNDAY FOR KSZ030-031-045-046-061-064>066-074-078>081-084-
088>090.
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR KSZ043-
044-061>063-074>077-084>087.
HIGH WIND WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR
KSZ043-044-062-063-075>077-085>087.
&&
$$
FN99/99/36
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1039 AM MST SAT JAN 21 2012
.DISCUSSION...
420 AM MST SAT JAN 21 2012
MAIN FORECAST PROBLEM WILL BE THE WINDS THROUGH SUNDAY BUT MANY
OTHER CONCERNS ARE JUST BELOW THE WINDS. SATELLITE SHOWING AN
ACTIVE/PROGRESSIVE WAVE TRAIN FROM THE PACIFIC INTO THE WESTERN
ATLANTIC. BROAD UPPER TROUGH REMAINS IN PLACE OVER THE PACIFIC WITH
A STRONG SHORTWAVE TROUGH APPROACHING THE WEST COAST. ALSO BIG LOW
LEVEL TEMPERATURE GRADIENT SLIDING BACK AND FORTH ACROSS THE AREA.
AT JET LEVEL...EXTREMELY STRONG JET OVER THE EASTERN PACIFIC BEHIND
INCOMING TROUGH. BASED ON WHAT OBSERVATIONS ARE OUT THERE...THE
MODELS ARE UNDERDOING THE STRENGTH OF THE NEAR 200 KNOT JET. BASED
ON AVAILABLE DATA...THE GFS AND NAM LOOK TO HAVE THE BEST STRENGTH
BUT THE NAM/CANADIAN HAVE BEST ORIENTATION. OVER THE COUNTRY...THE
NAM AND CANADIAN HAVE THE BEST HANDLE ON THE JET THAT STARTED NEAR
OUR AREA LAST NIGHT. THE OTHER MODELS TENDED TO BE TOO FAR EAST.
SATELLITE AND UPPER AIR WOULD SUPPORT THE ECMWF/CANADIAN BEING THE
BEST AT MID LEVELS. MODELS TENDED TO BE TOO MOIST AT MID LEVELS
WITH THE CANADIAN AND UKMET DOING THE BEST. MODELS CONTINUING TO
HAVE TROUBLE WITH THE LOW LEVEL THERMAL FIELD. OVERALL THE UKMET AND
CANADIAN WAS DOING A LITTLE BETTER THAN THE GFS...ESPECIALLY WITH
THE POSITION OF THE COLD POOL TO OUR NORTH AND EAST.
TODAY/TONIGHT...NEWER GUIDANCE HAS COME IN A LITTLE STRONGER WITH
THE WINDS. MODELS SHOW LITTLE TO NO MIXING TODAY WITH LOUSY LOW
LEVEL LAPSE RATES. WHICH AM NOT ENTIRELY SURE ABOUT. INITIAL
QUESTION TO HELP WITH THAT WILL BE HOW MUCH CLOUD COVER WILL MOVE IN
TODAY. IMPRESSIVE CLOUD SHIELD OUT TO OUR WEST. THE BETTER MODELS IN
REGARDS TO THIS MOISTURE WOULD SAY THAT THE CLOUDS REALLY DO NOT
THICKEN UP UNTIL THIS AFTERNOON. HOWEVER...DESPITE THE LACK OF
MIXING WHAT MAY BE THE MAIN DRIVING FORCE BEHIND THESE WINDS COULD
THE TIGHTENING PRESSURE GRADIENT AND PRETTY HIGH 3 HOUR PRESSURE
FALLS THROUGH THE AFTERNOON. GOING BY WHAT LIMITED MIXING BUFKIT
SHOWS...WINDS LOOK TO REACH ADVISORY CRITERIA. IT WILL BE CLOSE BUT
CHOSE TO ISSUE A WIND ADVISORY FOR ALL BUT THE FAR EASTERN TWO
COUNTIES. ADVISORY MAY BE MARGINAL FOR THOSE EASTERN COUNTIES BUT
WILL BE PLAYING THIS ON THE SAFE SIDE.
MODELS HAVE HAD A HORRIBLE TIME WITH TEMPERATURE GRADIENT ACROSS THE
AREA. THICKENING CLOUD COVER WILL MAKE THIS EVEN MORE PROBLEMATIC.
LOW LEVEL THERMAL PROFILES CLUSTER AROUND A LITTLE WARMER
TEMPERATURES THAN WHAT IS IN THERE. CANADIAN SURFACE TEMPERATURE
MATCHES UP WELL WITH WHAT THE HRRR IS SHOWING. SO WARMED UP
TEMPERATURES SOME IN LINE WITH THOSE MODELS.
STRONG INCOMING SYSTEM BEGINS TO AFFECT THE AREA LATE TONIGHT.
DEEPER MOISTURE AND LIFT ALONG WITH DECENT LAPSE RATES COME INTO
THE WEST LATE. MORE MODEL QPF SHOWING QPF IN THIS AREA AND SEEMS
REASONABLE CONSIDERING THE LIFT AND INSTABILITY. QUESTION THEN
BECOMES PHASE. LOW LEVEL THERMAL GUIDANCE AND SOUNDING SHOW VERY
MILD OVERNIGHT TEMPERATURES IN ADVANCE OF THE SYSTEM. THE ONLY
PLACE THAT LOOKS TO BE NEAR FREEZING IS IN THE EAST WHERE
PRECIPITATION IS NOT EXPECTED AT THIS TIME. RAISED MINS ACROSS THE
REMAINDER OF THE AREA. CONSIDERING THE POSSIBILITY OF A LITTLE MORE
INTENSE PRECIPITATION AND BEING A LITTLE WARM...DID A RAIN AND SNOW
MIX IN THE FAR WEST WITH SPRINKLES TO THE EAST OF THERE.
SUNDAY/SUNDAY NIGHT...LEFT FRONT QUADRANT OF THE JET STARTS OUT OVER
THE EASTERN HALF OF THE AREA AT 12Z AND THEN IT QUICKLY MOVES EAST.
STRONG UPPER TROUGH MOVES THROUGH DURING THE DAY. BASED ON
SATELLITE...STRONG JET ASSOCIATED WITH THE SYSTEM...AND STRONG PV
ANOMALY INDICATED...BELIEVE THE MODELS ARE UNDERDOING THE STRENGTH OF
THE SYSTEM. COMBINATION OF STRONG LIFT/PV ANOMALY AND FAVORABLE
THETA-E LAPSE RATES...WILL BRING A GOOD CHANCE OF A LIGHT MEASURABLE
PRECIPITATION EVENT TO THE AREA. BASED ON THE PREVIOUS REASONING...
GEFS PROBABILITIES...AND LOCAL POP PROGRAM...RAISED POPS OVER THE
ENTIRE FORECAST AREA...ESPECIALLY IN THE EAST. DAY SHIFT WILL HAVE
TO LOOK AT RAISING THESE POPS EVEN MORE. PHASE REMAINS A PROBLEM.
MODELS DO NOT SHOW A LOT OF COLD AIR. IT IS POSSIBLE WITH THE MOST
INTENSE PRECIPITATION SNOW COULD MIX WITH THE RAIN IN THE MORNING.
AT THIS TIME KEPT THE MIXED PHASE IN THE MORNING WITH ALL RAIN IN
THE AFTERNOON.
HOWEVER...WHAT LOOKS TO BE THE MAIN STORY WILL ONCE AGAIN BE THE
WINDS. STRONG SUBSIDENCE BEHIND THE WAVE/EXITING PRECIPITATION
COMBINED WITH VERY GOOD LAPSE RATES AND 3 HOUR PRESSURE RISES
SHOULD BRING A HIGH END WIND ADVISORY EVENT TO THE ENTIRE AREA.
HOWEVER...STRONGEST 3 HOUR PRESSURE RISES ARE OUT AHEAD OF THE MAIN
SUBSIDENCE. WHAT IS CONCERNING IS THAT IF PARAMETERS CAN COME
TOGETHER A LITTLE BETTER...IT IS POSSIBLE THAT WARNING CRITERIA
COULD BE MET. DAY SHIFT WILL HAVE TO LOOK AT THIS AGAIN...AND CHOOSE
THE APPROPRIATE HIGHLIGHT. CHOSE TO GO SLIGHTLY BELOW THE GUIDANCE
WHICH WAS IN PRETTY CLOSE AGREEMENT. PRECIPITATION SHOULD BE DONE BY
THE NIGHT AND WILL PROBABLY COOL BELOW GUIDANCE.
MONDAY/MONDAY NIGHT...QUESTION WILL BE HOW MUCH TO WARM
TEMPERATURES. WILL HAVE A COLD START PLUS EXITING SURFACE HIGH AND
DEVELOPING LEE TROUGH WILL CAUSE THE WINDS TO BE MORE FROM AN
UPSLOPE DIRECTION. SO TRENDED SLIGHTLY COOLER THAN THAN GUIDANCE.
NEXT FRONT STARTS MOVING THROUGH DURING THE NIGHT AND MADE NO
CHANGES TO THE TONIGHT PERIOD.
BULLER
TUESDAY THROUGH FRIDAY...SHORTWAVE RIDGE BREAKS DOWN AS TROUGH OVER
GREAT BASIN SHIFTS EAST ACROSS THE INTERMOUNTAIN WEST. GUIDANCE IN
GENERAL AGREEMENT ON H5 CLOSED LOW DEVELOPING OVER NEW MEXICO
TUESDAY MORNING...WITH SHORTWAVE TROUGH KICKING EAST ACROSS THE CWA
BY 18Z TUESDAY. MOISTURE ISNT VERY IMPRESSIVE WITH THIS SYSTEM...
WITH CLOSED LOW KEEPING GULF MOISTURE MUCH FURTHER SOUTH. HOWEVER
THERE IS A NARROW WINDOW WHERE LARGE SCALE ASCENT AND LIMITED
MOISTURE ADVECT IS PRESENT OVER PARTS OF THE CWA. FOR NOW HAVE KEPT
SLIGHT CHANCE POPS ACROSS WESTERN LOCATIONS DURING THE DAY TUESDAY...
AND IN THE FAR EASTERN DURING THE EVENING. SHORTWAVE RIDGE DEVELOPS
ACROSS THE SW US WEDNESDAY AND THURSDAY AS TROUGH SHIFTS EAST...WITH
NW FLOW JUST NORTH OF THIS FEATURE OVER THE CWA. LEE TROUGH DEVELOPS
THURSDAY BENEATH THIS PATTERN WITH S/SW FLOW AT THE SURFACE
SUPPORTING A BRIEF RETURN TO TEMPS IN THE 50S/NEAR 60 THURSDAY
AFTERNOON. NW FLOW PERSISTS THROUGH FRIDAY...WITH SHORTWAVE
TROUGH PUSHING EAST TOWARDS THE PLAINS FRIDAY NIGHT. GUIDANCE IS ALL
OVER THE PLACE ON THE EXACT TRACK OF THIS FEATURE...SO NOT ENOUGH
CONFIDENCE TO ADD PRECIP AT THIS POINT.
DR
THANKS TO ALL THAT COLLABORATED.
&&
.AVIATION...
1039 AM MST SAT JAN 21 2012
FOR THE 18Z TAFS...GUSTY WINDS WILL IMPACT THE TERMINALS TODAY AND
TOMORROW...AND THERE IS ALSO THE POSSIBILITY OF PRECIPITATION
TOMORROW. FOR TODAY...GIVEN THE POSITION OF KGLD RELATIVE TO THE LEE
TROUGH...HAVE INCLUDED STRONGER WINDS AT KGLD COMPARED TO KMCK.
WINDS WILL WEAKEN TONIGHT...BUT GUSTS ARE EXPECTED TO CONTINUE FOR A
FEW HOURS TONIGHT AT KGLD AS THE LEE TROUGH WEAKENS. AS AN UPPER
TROUGH MOVES OVER THE AREA...WINDS WILL SHIFT TO NORTHWESTERLY AND
INCREASE DURING THE MID MORNING. THE TROUGH WILL ALSO BRING THE
POSSIBILITY OF A LIGHT RAIN/SNOW MIX TO THE TERMINALS. CONFIDENCE
ABOUT PRECIP IS HIGHER AT KMCK...AND WHILE NAM SOUNDINGS ALSO
SUPPORT MVFR CEILINGS AT KMCK...IT IS MORE LIKELY THAT CEILINGS WILL
REMAIN IN THE LOW VFR RANGE. THE WIND COULD CAUSE VISIBILITIES LOWER
THAN VFR WHEN COMBINED WITH LIGHT PRECIP...ESPECIALLY IF SNOW ENDS
UP DOMINATING...BUT CONFIDENCE TOO LOW AT THIS TIME TO INCLUDE
SUB-VFR CONDITIONS.
CJS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 6 PM MST /7 PM CST/ THIS EVENING FOR
KSZ001>003-013>015-027>029-041-042.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR KSZ013-027-041.
NE...WIND ADVISORY UNTIL 6 PM MST /7 PM CST/ THIS EVENING FOR
NEZ079>081.
CO...WIND ADVISORY UNTIL 6 PM MST THIS EVENING FOR COZ090>092.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR COZ252>254.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1133 AM CST SAT JAN 21 2012
...UPDATE TO AVIATION...
.DISCUSSION...
WEAK UPPER TROF WAS EXITING EASTERN KANSAS EARLY THIS MORNING WHILE
MUCH STRONGER WAVE WAS APPROACHING THE WEST COAST PER WATER VAPOR
IMAGERY. SURFACE RIDGE AXIS REMAINS ACROSS CENTRAL KANSAS..WITH
WIDESPREAD STRATUS OOZING SOUTHWEST JUST AHEAD OF IT INTO EAST
CENTRAL KANSAS...AND MORE SCATTERED LOW CLOUD TO ITS NORTHWEST IN
NORTH CENTRAL KANSAS AND EASTERN NEBRASKA. STRONG PRESSURE FALLS
WERE OCCURRING IN THE NORTHERN HIGH PLAINS UNDER QUICK ZONAL FLOW
ALOFT.
LATEST RUC SEEMS TO BE DOING FAIRLY WELL WITH LOW CLOUD TRENDS...AND
SEEMS REASONABLE WITH STRATUS CONTINUING SOUTHWEST THROUGH EAST
CENTRAL KANSAS...BUT MAKING LITTLE PROGRESS ELSEWHERE. SHOULD SEE
MOSTLY CLEAR SKIES TAKE HOLD BY LATE MORNING. SOUTH WINDS WILL
DEVELOP THIS AFTERNOON AS THE RIDGE PUSHES EAST WITH TEMPERATURES
RISING TO AROUND FREEZING. LITTLE IN THE WAY OF DIURNAL TEMP FALLS
EXPECTED TONIGHT WITH TIGHT PRESSURE GRADIENT DEVELOPING IN
EASTERN KANSAS UNDER 30-50KT SOUTH 925MB WINDS. MODEST LOW LEVEL
MOISTURE SHOULD RESULT IN STRATUS INTRUSION IN AT LEAST EASTERN
AREAS.
MAIN FOCUS FOR THE EARLY PERIODS IS STILL THE UPPER TROFS SPEED AND
STRENGTH AS IT PASSES THROUGH THE PLAINS SUNDAY AND SUNDAY NIGHT.
SIMILAR TO RUNS OF THURSDAY NIGHT...THE NAM IS ON THE QUICK
SIDE...ECMWF ON THE SLOW SIDE...AND OTHERS IN BETWEEN. HAVE SIDED
CLOSEST TO THE LARGER DOMAIN MODELS THINKING THEY SHOULD HAVE THE
BEST HANDLE ON THIS OFF-SHORE SYSTEM...SPECIFICALLY CLOSEST TO THE
ECMWF AND GEM. THIS DELAYS THE BEST PRECIPITATION CHANCES TO LATE
SUNDAY AFTERNOON AND INTO SUNDAY EVENING. 850MB TEMPS RISE INTO THE
10-12C RANGE TONIGHT...AND DESPITE STRONG AND DEEP COLD AIR
ADVECTION WITH THIS SYSTEM...CHANGEOVER TO AN ALL SNOW TYPE SHOULD
BE DELAYED UNTIL SUNDAY EVENING. PRECIP WILL LIKELY COINCIDE WITH
STRONG NORTHWEST WINDS BEHIND THE PACIFIC FRONT...BUT PRECIP
RATES/AMOUNTS AND SPEEDS SHOULD BE LOW ENOUGH TO PRECLUDE ANY
HEADLINES. DEEPER MIXING BEHIND THE SYSTEM MONDAY SHOULD PUSH HIGHS
BACK INTO THE 40S.
TREND FOR THE TUESDAY INTO WEDNESDAY PERIODS CONTINUES TO BE FOR
BULK OF ENERGY WITH THE NEXT SHORTWAVE TO DIVE SOUTHEAST...WITH LITTLE
FORCING FOR PRECIPITATION THIS FAR NORTH. THERE REMAINS SOME
SIGNAL FOR LIGHT AND SPOTTY ACCUMS TO OCCUR...AND SOME MENTION
WILL REMAIN FOR TUESDAY AFTERNOON IN THE WEST AND AREA-WIDE
TUESDAY NIGHT. TEMPERATURE PROFILES SHOULD SUPPORT RAIN-SNOW
AGAIN. ZONAL FLOW SHOULD MAINTAIN ITSELF NORTH OF THE UPPER LOW
WITH SOMEWHAT ABOVE NORMAL TEMPS RESULTING.
65
&&
.AVIATION...
MVFR STRATUS DECK HAS BEGUN TO VERY SLOWLY ERODE ON THE WESTERN
FRINGES AND EXPECT THE CIGS TO SCATTER OUT FIRST AT MHK AND THEN
AT TOP/FOE THIS AFTERNOON. EXACT TIMING IS UNCERTAIN BUT
HIGHLIGHTED MOST LIKELY TIMING WITH A TEMPO GROUP. EXPECT A PERIOD
OF VFR CONDITIONS FROM THAT POINT THROUGH 09Z-11Z WHEN LOW STRATUS
IS AGAIN EXPECTED TO DEVELOP ALONG WITH SOME MINOR VIS RESTRICTIONS.
HIGHER CONFIDENCE IN CIGS AT TOP/FOE THAN MHK BUT POTENTIAL EXISTS
FOR MVFR...TO PERHAPS IFR CIGS BY SUNRISE SUNDAY MORNING. THIS
SHOULD THEN LAST THROUGH THE END OF THE TAF PERIOD.
BARJENBRUCH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
559 AM CST SAT JAN 21 2012
...UPDATE TO AVIATION...
.DISCUSSION...
WEAK UPPER TROF WAS EXITING EASTERN KANSAS EARLY THIS MORNING WHILE
MUCH STRONGER WAVE WAS APPROACHING THE WEST COAST PER WATER VAPOR
IMAGERY. SURFACE RIDGE AXIS REMAINS ACROSS CENTRAL KANSAS..WITH
WIDESPREAD STRATUS OOZING SOUTHWEST JUST AHEAD OF IT INTO EAST
CENTRAL KANSAS...AND MORE SCATTERED LOW CLOUD TO ITS NORTHWEST IN
NORTH CENTRAL KANSAS AND EASTERN NEBRASKA. STRONG PRESSURE FALLS
WERE OCCURRING IN THE NORTHERN HIGH PLAINS UNDER QUICK ZONAL FLOW
ALOFT.
LATEST RUC SEEMS TO BE DOING FAIRLY WELL WITH LOW CLOUD TRENDS...AND
SEEMS REASONABLE WITH STRATUS CONTINUING SOUTHWEST THROUGH EAST
CENTRAL KANSAS...BUT MAKING LITTLE PROGRESS ELSEWHERE. SHOULD SEE
MOSTLY CLEAR SKIES TAKE HOLD BY LATE MORNING. SOUTH WINDS WILL
DEVELOP THIS AFTERNOON AS THE RIDGE PUSHES EAST WITH TEMPERATURES
RISING TO AROUND FREEZING. LITTLE IN THE WAY OF DIURNAL TEMP FALLS
EXPECTED TONIGHT WITH TIGHT PRESSURE GRADIENT DEVELOPING IN
EASTERN KANSAS UNDER 30-50KT SOUTH 925MB WINDS. MODEST LOW LEVEL
MOISTURE SHOULD RESULT IN STRATUS INTRUSION IN AT LEAST EASTERN
AREAS.
MAIN FOCUS FOR THE EARLY PERIODS IS STILL THE UPPER TROFS SPEED AND
STRENGTH AS IT PASSES THROUGH THE PLAINS SUNDAY AND SUNDAY NIGHT.
SIMILAR TO RUNS OF THURSDAY NIGHT...THE NAM IS ON THE QUICK
SIDE...ECMWF ON THE SLOW SIDE...AND OTHERS IN BETWEEN. HAVE SIDED
CLOSEST TO THE LARGER DOMAIN MODELS THINKING THEY SHOULD HAVE THE
BEST HANDLE ON THIS OFF-SHORE SYSTEM...SPECIFICALLY CLOSEST TO THE
ECMWF AND GEM. THIS DELAYS THE BEST PRECIPITATION CHANCES TO LATE
SUNDAY AFTERNOON AND INTO SUNDAY EVENING. 850MB TEMPS RISE INTO THE
10-12C RANGE TONIGHT...AND DESPITE STRONG AND DEEP COLD AIR
ADVECTION WITH THIS SYSTEM...CHANGEOVER TO AN ALL SNOW TYPE SHOULD
BE DELAYED UNTIL SUNDAY EVENING. PRECIP WILL LIKELY COINCIDE WITH
STRONG NORTHWEST WINDS BEHIND THE PACIFIC FRONT...BUT PRECIP
RATES/AMOUNTS AND SPEEDS SHOULD BE LOW ENOUGH TO PRECLUDE ANY
HEADLINES. DEEPER MIXING BEHIND THE SYSTEM MONDAY SHOULD PUSH HIGHS
BACK INTO THE 40S.
TREND FOR THE TUESDAY INTO WEDNESDAY PERIODS CONTINUES TO BE FOR
BULK OF ENERGY WITH THE NEXT SHORTWAVE TO DIVE SOUTHEAST...WITH LITTLE
FORCING FOR PRECIPITATION THIS FAR NORTH. THERE REMAINS SOME
SIGNAL FOR LIGHT AND SPOTTY ACCUMS TO OCCUR...AND SOME MENTION
WILL REMAIN FOR TUESDAY AFTERNOON IN THE WEST AND AREA-WIDE
TUESDAY NIGHT. TEMPERATURE PROFILES SHOULD SUPPORT RAIN-SNOW
AGAIN. ZONAL FLOW SHOULD MAINTAIN ITSELF NORTH OF THE UPPER LOW
WITH SOMEWHAT ABOVE NORMAL TEMPS RESULTING.
65
&&
.AVIATION...
SCT TO BKN MVFR CEILINGS WITH BASES OF 2200 FT TO 2800 FT WILL
CONTINUE ACROSS THE TAF SITE THIS MORNING. WEAK ISENTROPIC LIFT
ACROSS EASTERN KS THIS MORNING WILL SLOWLY DIMINISH AFTER 16Z
ALLOWING SKIES TO BECOME CLEAR. NORTHEAST WINDS OF 5 TO 10 KTS THIS
MORNING SWITCH TO THE SOUTHEAST AND SOUTH THROUGH THE AFTERNOON HOURS.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
420 AM MST SAT JAN 21 2012
.DISCUSSION...
420 AM MST SAT JAN 21 2012
MAIN FORECAST PROBLEM WILL BE THE WINDS THROUGH SUNDAY BUT MANY
OTHER CONCERNS ARE JUST BELOW THE WINDS. SATELLITE SHOWING AN
ACTIVE/PROGRESSIVE WAVE TRAIN FROM THE PACIFIC INTO THE WESTERN
ATLANTIC. BROAD UPPER TROUGH REMAINS IN PLACE OVER THE PACIFIC WITH
A STRONG SHORTWAVE TROUGH APPROACHING THE WEST COAST. ALSO BIG LOW
LEVEL TEMPERATURE GRADIENT SLIDING BACK AND FORTH ACROSS THE AREA.
AT JET LEVEL...EXTREMELY STRONG JET OVER THE EASTERN PACIFIC BEHIND
INCOMING TROUGH. BASED ON WHAT OBSERVATIONS ARE OUT THERE...THE
MODELS ARE UNDERDOING THE STRENGTH OF THE NEAR 200 KNOT JET. BASED
ON AVAILABLE DATA...THE GFS AND NAM LOOK TO HAVE THE BEST STRENGTH
BUT THE NAM/CANADIAN HAVE BEST ORIENTATION. OVER THE COUNTRY...THE
NAM AND CANADIAN HAVE THE BEST HANDLE ON THE JET THAT STARTED NEAR
OUR AREA LAST NIGHT. THE OTHER MODELS TENDED TO BE TOO FAR EAST.
SATELLITE AND UPPER AIR WOULD SUPPORT THE ECMWF/CANADIAN BEING THE
BEST AT MID LEVELS. MODELS TENDED TO BE TOO MOIST AT MID LEVELS
WITH THE CANADIAN AND UKMET DOING THE BEST. MODELS CONTINUING TO
HAVE TROUBLE WITH THE LOW LEVEL THERMAL FIELD. OVERALL THE UKMET AND
CANADIAN WAS DOING A LITTLE BETTER THAN THE GFS...ESPECIALLY WITH
THE POSITION OF THE COLD POOL TO OUR NORTH AND EAST.
TODAY/TONIGHT...NEWER GUIDANCE HAS COME IN A LITTLE STRONGER WITH
THE WINDS. MODELS SHOW LITTLE TO NO MIXING TODAY WITH LOUSY LOW
LEVEL LAPSE RATES. WHICH AM NOT ENTIRELY SURE ABOUT. INITIAL
QUESTION TO HELP WITH THAT WILL BE HOW MUCH CLOUD COVER WILL MOVE IN
TODAY. IMPRESSIVE CLOUD SHIELD OUT TO OUR WEST. THE BETTER MODELS IN
REGARDS TO THIS MOISTURE WOULD SAY THAT THE CLOUDS REALLY DO NOT
THICKEN UP UNTIL THIS AFTERNOON. HOWEVER...DESPITE THE LACK OF
MIXING WHAT MAY BE THE MAIN DRIVING FORCE BEHIND THESE WINDS COULD
THE TIGHTENING PRESSURE GRADIENT AND PRETTY HIGH 3 HOUR PRESSURE
FALLS THROUGH THE AFTERNOON. GOING BY WHAT LIMITED MIXING BUFKIT
SHOWS...WINDS LOOK TO REACH ADVISORY CRITERIA. IT WILL BE CLOSE BUT
CHOSE TO ISSUE A WIND ADVISORY FOR ALL BUT THE FAR EASTERN TWO
COUNTIES. ADVISORY MAY BE MARGINAL FOR THOSE EASTERN COUNTIES BUT
WILL BE PLAYING THIS ON THE SAFE SIDE.
MODELS HAVE HAD A HORRIBLE TIME WITH TEMPERATURE GRADIENT ACROSS THE
AREA. THICKENING CLOUD COVER WILL MAKE THIS EVEN MORE PROBLEMATIC.
LOW LEVEL THERMAL PROFILES CLUSTER AROUND A LITTLE WARMER
TEMPERATURES THAN WHAT IS IN THERE. CANADIAN SURFACE TEMPERATURE
MATCHES UP WELL WITH WHAT THE HRRR IS SHOWING. SO WARMED UP
TEMPERATURES SOME IN LINE WITH THOSE MODELS.
STRONG INCOMING SYSTEM BEGINS TO AFFECT THE AREA LATE TONIGHT.
DEEPER MOISTURE AND LIFT ALONG WITH DECENT LAPSE RATES COME INTO
THE WEST LATE. MORE MODEL QPF SHOWING QPF IN THIS AREA AND SEEMS
REASONABLE CONSIDERING THE LIFT AND INSTABILITY. QUESTION THEN
BECOMES PHASE. LOW LEVEL THERMAL GUIDANCE AND SOUNDING SHOW VERY
MILD OVERNIGHT TEMPERATURES IN ADVANCE OF THE SYSTEM. THE ONLY
PLACE THAT LOOKS TO BE NEAR FREEZING IS IN THE EAST WHERE
PRECIPITATION IS NOT EXPECTED AT THIS TIME. RAISED MINS ACROSS THE
REMAINDER OF THE AREA. CONSIDERING THE POSSIBILITY OF A LITTLE MORE
INTENSE PRECIPITATION AND BEING A LITTLE WARM...DID A RAIN AND SNOW
MIX IN THE FAR WEST WITH SPRINKLES TO THE EAST OF THERE.
SUNDAY/SUNDAY NIGHT...LEFT FRONT QUADRANT OF THE JET STARTS OUT OVER
THE EASTERN HALF OF THE AREA AT 12Z AND THEN IT QUICKLY MOVES EAST.
STRONG UPPER TROUGH MOVES THROUGH DURING THE DAY. BASED ON
SATELLITE...STRONG JET ASSOCIATED WITH THE SYSTEM...AND STRONG PV
ANOMALY INDICATED...BELIEVE THE MODELS ARE UNDERDOING THE STRENGTH OF
THE SYSTEM. COMBINATION OF STRONG LIFT/PV ANOMALY AND FAVORABLE
THETA-E LAPSE RATES...WILL BRING A GOOD CHANCE OF A LIGHT MEASURABLE
PRECIPITATION EVENT TO THE AREA. BASED ON THE PREVIOUS REASONING...
GEFS PROBABILITIES...AND LOCAL POP PROGRAM...RAISED POPS OVER THE
ENTIRE FORECAST AREA...ESPECIALLY IN THE EAST. DAY SHIFT WILL HAVE
TO LOOK AT RAISING THESE POPS EVEN MORE. PHASE REMAINS A PROBLEM.
MODELS DO NOT SHOW A LOT OF COLD AIR. IT IS POSSIBLE WITH THE MOST
INTENSE PRECIPITATION SNOW COULD MIX WITH THE RAIN IN THE MORNING.
AT THIS TIME KEPT THE MIXED PHASE IN THE MORNING WITH ALL RAIN IN
THE AFTERNOON.
HOWEVER...WHAT LOOKS TO BE THE MAIN STORY WILL ONCE AGAIN BE THE
WINDS. STRONG SUBSIDENCE BEHIND THE WAVE/EXITING PRECIPITATION
COMBINED WITH VERY GOOD LAPSE RATES AND 3 HOUR PRESSURE RISES
SHOULD BRING A HIGH END WIND ADVISORY EVENT TO THE ENTIRE AREA.
HOWEVER...STRONGEST 3 HOUR PRESSURE RISES ARE OUT AHEAD OF THE MAIN
SUBSIDENCE. WHAT IS CONCERNING IS THAT IF PARAMETERS CAN COME
TOGETHER A LITTLE BETTER...IT IS POSSIBLE THAT WARNING CRITERIA
COULD BE MET. DAY SHIFT WILL HAVE TO LOOK AT THIS AGAIN...AND CHOOSE
THE APPROPRIATE HIGHLIGHT. CHOSE TO GO SLIGHTLY BELOW THE GUIDANCE
WHICH WAS IN PRETTY CLOSE AGREEMENT. PRECIPITATION SHOULD BE DONE BY
THE NIGHT AND WILL PROBABLY COOL BELOW GUIDANCE.
MONDAY/MONDAY NIGHT...QUESTION WILL BE HOW MUCH TO WARM
TEMPERATURES. WILL HAVE A COLD START PLUS EXITING SURFACE HIGH AND
DEVELOPING LEE TROUGH WILL CAUSE THE WINDS TO BE MORE FROM AN
UPSLOPE DIRECTION. SO TRENDED SLIGHTLY COOLER THAN THAN GUIDANCE.
NEXT FRONT STARTS MOVING THROUGH DURING THE NIGHT AND MADE NO
CHANGES TO THE TONIGHT PERIOD.
BULLER
TUESDAY THROUGH FRIDAY...SHORTWAVE RIDGE BREAKS DOWN AS TROUGH OVER
GREAT BASIN SHIFTS EAST ACROSS THE INTERMOUNTAIN WEST. GUIDANCE IN
GENERAL AGREEMENT ON H5 CLOSED LOW DEVELOPING OVER NEW MEXICO
TUESDAY MORNING...WITH SHORTWAVE TROUGH KICKING EAST ACROSS THE CWA
BY 18Z TUESDAY. MOISTURE ISNT VERY IMPRESSIVE WITH THIS SYSTEM...
WITH CLOSED LOW KEEPING GULF MOISTURE MUCH FURTHER SOUTH. HOWEVER
THERE IS A NARROW WINDOW WHERE LARGE SCALE ASCENT AND LIMITED
MOISTURE ADVECT IS PRESENT OVER PARTS OF THE CWA. FOR NOW HAVE KEPT
SLIGHT CHANCE POPS ACROSS WESTERN LOCATIONS DURING THE DAY TUESDAY...
AND IN THE FAR EASTERN DURING THE EVENING. SHORTWAVE RIDGE DEVELOPS
ACROSS THE SW US WEDNESDAY AND THURSDAY AS TROUGH SHIFTS EAST...WITH
NW FLOW JUST NORTH OF THIS FEATURE OVER THE CWA. LEE TROUGH DEVELOPS
THURSDAY BENEATH THIS PATTERN WITH S/SW FLOW AT THE SURFACE
SUPPORTING A BRIEF RETURN TO TEMPS IN THE 50S/NEAR 60 THURSDAY
AFTERNOON. NW FLOW PERSISTS THROUGH FRIDAY...WITH SHORTWAVE
TROUGH PUSHING EAST TOWARDS THE PLAINS FRIDAY NIGHT. GUIDANCE IS ALL
OVER THE PLACE ON THE EXACT TRACK OF THIS FEATURE...SO NOT ENOUGH
CONFIDENCE TO ADD PRECIP AT THIS POINT.
DR
THANKS TO ALL THAT COLLABORATED.
&&
.AVIATION...
420 AM MST SAT JAN 21 2012
FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT
BOTH KGLD AND KMCK TERMINALS. SOUTHERLY WINDS WILL INCREASE THROUGH
THE MORNING AT BOTH TERMINALS AS LEE TROUGH STRENGTHENS THROUGH THE
DAY. AFTERNOON GUSTS UP TO 40KT ARE POSSIBLE AT KGLD...WITH GUSTS
AROUND 30KT AT KMCK. WHILE WINDS SHOULD DECREASE AT BOTH TERMINALS
AFTER 00Z...I STILL EXPECT GUSTY CONDITIONS TO CONTINUE THROUGH MOST
OF THE EVENING AT KGLD. WINDS WILL SHIFT TO THE WEST AROUND 09-10Z
AT BOTH TERMINALS AS SURFACE TROUGH SHIFTS EAST.
DR
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM 10 AM MST /11 AM CST/ THIS MORNING TO 6 PM
MST /7 PM CST/ THIS EVENING FOR KSZ001>003-013>015-027>029-
041-042.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR KSZ013-027-041.
NE...WIND ADVISORY FROM 10 AM MST /11 AM CST/ THIS MORNING TO 6 PM
MST /7 PM CST/ THIS EVENING FOR NEZ079>081.
CO...WIND ADVISORY FROM 10 AM THIS MORNING TO 6 PM MST THIS EVENING
FOR COZ090>092.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR COZ252>254.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
321 AM CST SAT JAN 21 2012
.DISCUSSION...
WEAK UPPER TROF WAS EXITING EASTERN KANSAS EARLY THIS MORNING WHILE
MUCH STRONGER WAVE WAS APPROACHING THE WEST COAST PER WATER VAPOR
IMAGERY. SURFACE RIDGE AXIS REMAINS ACROSS CENTRAL KANSAS..WITH
WIDESPREAD STRATUS OOZING SOUTHWEST JUST AHEAD OF IT INTO EAST
CENTRAL KANSAS...AND MORE SCATTERED LOW CLOUD TO ITS NORTHWEST IN
NORTH CENTRAL KANSAS AND EASTERN NEBRASKA. STRONG PRESSURE FALLS
WERE OCCURRING IN THE NORTHERN HIGH PLAINS UNDER QUICK ZONAL FLOW
ALOFT.
LATEST RUC SEEMS TO BE DOING FAIRLY WELL WITH LOW CLOUD TRENDS...AND
SEEMS REASONABLE WITH STRATUS CONTINUING SOUTHWEST THROUGH EAST
CENTRAL KANSAS...BUT MAKING LITTLE PROGRESS ELSEWHERE. SHOULD SEE
MOSTLY CLEAR SKIES TAKE HOLD BY LATE MORNING. SOUTH WINDS WILL
DEVELOP THIS AFTERNOON AS THE RIDGE PUSHES EAST WITH TEMPERATURES
RISING TO AROUND FREEZING. LITTLE IN THE WAY OF DIURNAL TEMP FALLS
EXPECTED TONIGHT WITH TIGHT PRESSURE GRADIENT DEVELOPING IN
EASTERN KANSAS UNDER 30-50KT SOUTH 925MB WINDS. MODEST LOW LEVEL
MOISTURE SHOULD RESULT IN STRATUS INTRUSION IN AT LEAST EASTERN
AREAS.
MAIN FOCUS FOR THE EARLY PERIODS IS STILL THE UPPER TROFS SPEED AND
STRENGTH AS IT PASSES THROUGH THE PLAINS SUNDAY AND SUNDAY NIGHT.
SIMILAR TO RUNS OF THURSDAY NIGHT...THE NAM IS ON THE QUICK
SIDE...ECMWF ON THE SLOW SIDE...AND OTHERS IN BETWEEN. HAVE SIDED
CLOSEST TO THE LARGER DOMAIN MODELS THINKING THEY SHOULD HAVE THE
BEST HANDLE ON THIS OFF-SHORE SYSTEM...SPECIFICALLY CLOSEST TO THE
ECMWF AND GEM. THIS DELAYS THE BEST PRECIPITATION CHANCES TO LATE
SUNDAY AFTERNOON AND INTO SUNDAY EVENING. 850MB TEMPS RISE INTO THE
10-12C RANGE TONIGHT...AND DESPITE STRONG AND DEEP COLD AIR
ADVECTION WITH THIS SYSTEM...CHANGEOVER TO AN ALL SNOW TYPE SHOULD
BE DELAYED UNTIL SUNDAY EVENING. PRECIP WILL LIKELY COINCIDE WITH
STRONG NORTHWEST WINDS BEHIND THE PACIFIC FRONT...BUT PRECIP
RATES/AMOUNTS AND SPEEDS SHOULD BE LOW ENOUGH TO PRECLUDE ANY
HEADLINES. DEEPER MIXING BEHIND THE SYSTEM MONDAY SHOULD PUSH HIGHS
BACK INTO THE 40S.
TREND FOR THE TUESDAY INTO WEDNESDAY PERIODS CONTINUES TO BE FOR
BULK OF ENERGY WITH THE NEXT SHORTWAVE TO DIVE SOUTHEAST...WITH LITTLE
FORCING FOR PRECIPITATION THIS FAR NORTH. THERE REMAINS SOME
SIGNAL FOR LIGHT AND SPOTTY ACCUMS TO OCCUR...AND SOME MENTION
WILL REMAIN FOR TUESDAY AFTERNOON IN THE WEST AND AREA-WIDE
TUESDAY NIGHT. TEMPERATURE PROFILES SHOULD SUPPORT RAIN-SNOW
AGAIN. ZONAL FLOW SHOULD MAINTAIN ITSELF NORTH OF THE UPPER LOW
WITH SOMEWHAT ABOVE NORMAL TEMPS RESULTING.
65
&&
.AVIATION...
SATELLITE SHOWS AREA OF STRATUS OVER SOUTHWESTERN IA MAKING STEADY
PROGRESS TO THE SOUTH. THE LATEST RUC AND NAM DO NOT HAVE THE
GREATEST HANDEL ON THIS IN THEIR RH PROGS. SO THINK BASED ON
ADVECTION ONLY THAT THE STRATUS WILL MAKE A RUN AT TOP AND FOE. AM A
LITTLE CONCERNED WITH THE 925 WINDS PROGGED TO VEER TO THE EAST THAT
THE STRATUS MAY BE STUBBORN TO MIX OUT UNTIL THE SFC RIDGE AXIS
PASSES TO THE EAST. INITIALLY THE CIGS MAY COME IN AT 2500 FT BUT
BASED ON OBS UPSTREAM THINK THIS WILL BE TEMPORARY WITH CIGS LIFTING
TO 3 KFT OR BETTER. DO NOT HAVE ENOUGH CONFIDENCE IN THEM MAKING IT
TO MHK TO INCLUDE IT THERE AT THIS TIME. THE SFC RIDGE AXIS SHOULD
PASS TO THE EAST AROUND 18Z WITH VFR CONDITIONS EXPECTED TO PERSIST
AND A SOUTHEASTERLY WIND FRESHENING.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1052 PM CST FRI JAN 20 2012
...AVIATION UPDATE...
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
SATELLITE SHOWS AREA OF STRATUS OVER SOUTHWESTERN IA MAKING STEADY
PROGRESS TO THE SOUTH. THE LATEST RUC AND NAM DO NOT HAVE THE
GREATEST HANDEL ON THIS IN THEIR RH PROGS. SO THINK BASED ON
ADVECTION ONLY THAT THE STRATUS WILL MAKE A RUN AT TOP AND FOE. AM A
LITTLE CONCERNED WITH THE 925 WINDS PROGGED TO VEER TO THE EAST THAT
THE STRATUS MAY BE STUBBORN TO MIX OUT UNTIL THE SFC RIDGE AXIS
PASSES TO THE EAST. INITIALLY THE CIGS MAY COME IN AT 2500 FT BUT
BASED ON OBS UPSTREAM THINK THIS WILL BE TEMPORARY WITH CIGS LIFTING
TO 3 KFT OR BETTER. DO NOT HAVE ENOUGH CONFIDENCE IN THEM MAKING IT
TO MHK TO INCLUDE IT THERE AT THIS TIME. THE SFC RIDGE AXIS SHOULD
PASS TO THE EAST AROUND 18Z WITH VFR CONDITIONS EXPECTED TO PERSIST
AND A SOUTHEASTERLY WIND FRESHENING.
WOLTERS
&&
.PREV DISCUSSION... /330 PM CST FRI JAN 20 2012/
THROUGH SATURDAY...AN UPPER LEVEL DISTURBANCE WAS CROSSING THE
NORTHERN PLAINS INTO THE GREAT LAKES REGION THIS AFTERNOON WITH SNOW
WELL NORTH OF THE FORECAST AREA. SURFACE LOW PRESSURE WAS SITUATED
IN THE RED RIVER VALLEY WITH BROAD ISENTROPIC UPSLOPE FLOW PRODUCING
A LOW STRATUS CLOUD DECK FROM NORTHEAST OKLAHOMA INTO EASTERN KANSAS
AND POINTS EAST. THESE LOW CLOUDS COMBINED WITH WIDESPREAD HIGH
CLOUDS... SURFACE COLD ADVECTION AND SNOW COVER IN PARTS OF THE AREA
TO KEEP HIGH TEMPS IN THE UPPER 20S AND LOWER 30S TODAY.
HIGH PRESSURE WILL BUILD IN TO NORTHERN KANSAS BY MORNING WITH WINDS
DECREASING FROM NORTHWEST TO SOUTHEAST AFTER MIDNIGHT. SKIES WILL
ALSO CLEAR OUT AND TEMPERATURES WILL FALL QUICKLY AS SOON AS THE
WINDS DIMINISH. EXPECT THE COLDEST TEMPS TO BE IN AREAS WITH SNOW
COVER WHERE LOWS COULD APPROACH 0 DEGREES WHILE EAST CENTRAL KANSAS
WILL PROBABLY REMAIN IN THE TEENS AS WINDS ARE EXPECTED TO KEEP
THINGS MIXED THROUGH SUNRISE.
THE NEXT UPPER LEVEL SYSTEM WILL MOVE OUT INTO THE ROCKIES BY LATE
SATURDAY WITH LEE CYCLOGENESIS IN EASTERN COLORADO. SOUTHERLY RETURN
FLOW WILL KICK UP ACROSS KANSAS WITH A BIT OF WARM ADVECTION AS
WELL. TEMPS WILL WARM TO NEAR FREEZING OR A BIT WARMER IN ANY AREAS
FREE OF SNOW COVER BUT IT WILL STILL FEEL CHILLY WITH THE BREEZE.
BARJENBRUCH
SUNDAY THROUGH FRIDAY...STRONG WARM AIR ADVECTION STARTS UP ON
SUNDAY AS SOUTHERLY FLOW IN RESPONSE TO A DEEPENING SURFACE TROUGH
MOVES INTO THE AREA. EXPECT A FAIRLY SIGNIFICANT JUMP IN
TEMPERATURES FROM SATURDAY TO SUNDAY...AS HIGHS ON SUNDAY COULD
REACH INTO THE LOWER 50S...ESPECIALLY SOUTH AND EAST OF THE
TURNPIKE. AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY REACH
INTO THE MID TO UPPER 40S. ALTHOUGH THERE WILL BE SOME ISENTROPIC
LIFT ASSOCIATED WITH THE STRONG WARM AIR ADVECTION MARGINAL MOISTURE
RETURN AS INDICATED BY CONDENSATION PRESSURE DEFICITS WELL ABOVE 100
MB ON ALL ANALYZED ISENTROPIC SURFACES WILL PRECLUDE WARM AIR
ADVECTION SHOWERS ON SUNDAY MORNING. AS THE PARENT UPPER TROUGH DIGS
SOUTHWARD ENOUGH FORCING FOR ASCENT WILL BE PRESENT ALONG THE
LEADING 500 MB VORTICITY MAXIMUM THAT PRECIPITATION SHOULD COMMENCE
ACROSS THE AREA AROUND 18Z ON SUNDAY...MAINLY IN NORTH CENTRAL
KANSAS. PRECIP WILL SPREAD EASTWARD THROUGHOUT THE REST OF THE
AFTERNOON ON SUNDAY...STARTING MAINLY AS RAIN...THEN SWITCHING OVER
TO A RAIN/SNOW MIXTURE. THERMAL PROFILES INDICATE THAT NORTHEAST
KANSAS COULD SEE A BRIEF WINDOW WHERE SNOWFALL COULD OCCUR...HOWEVER
GIVEN THE MARGINAL SIGNALS FOR SNOW IN THE FORECAST SOUNDINGS WILL
CARRY A MIXTURE OF RAIN/SNOW MIX IN THE FORECAST FOR SUNDAY EVENING.
COLDER AIR MORE CONDUCIVE TO PURE SNOW FORMATION WILL MOVE INTO FAR
NORTHEAST KANSAS BY SUNDAY NIGHT LIKELY BRINGING A PERIOD OF PURE
SNOW TO AREAS NORTH OF INTERSTATE 70 ON WEDNESDAY NIGHT. EXPECT THE
UPPER TROUGH TO MOVE OUT OF THE AREA BY MONDAY MORNING WHICH WILL
CAUSE PRECIP TO COME TO AN END BY EARLY MONDAY MORNING.
EXPECT MILD CONDITIONS TO PERSIST AFTER THE RAIN/SNOW ENDS ON
SUNDAY...AS SHORTWAVE RIDGING MOVES INTO THE AREA FOR THE BEGINNING
TO MIDDLE PART OF THE WORK WEEK. THE NEXT CHANCE FOR PRECIP LOOKS TO
TAKE SHAPE TUESDAY NIGHT INTO WEDNESDAY MORNING AS STRONG WARM/MOIST
AIR ADVECTION PUSHES INTO THE AREA AHEAD OF THE NEXT UPPER TROUGH.
INTRODUCED PRECIP FOR LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
LASTING ROUGHLY THROUGH WEDNESDAY AFTERNOON. ONCE AGAIN THERMAL
PROFILES INDICATE A MARGINAL PRECIP TYPE EVENT...MEANING A RAIN/SNOW
MIXTURE IS EXPECTED FROM THIS EVENT ON TUESDAY/WEDNESDAY. EVEN
THOUGH PRECIP IS EXPECTED THROUGH TUESDAY AND WEDNESDAY EXPECT HIGHS
ALL WEEK TO REACH THE MID 40S TO POSSIBLY EVEN LOWER 50S.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
815 PM EST SUN JAN 22 2012
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MOVE EAST OF THE REGION OVERNIGHT
THROUGH MONDAY. LOW PRESSURE TRACKING FROM ONTARIO INTO CENTRAL
QUEBEC PROVINCES OF CANADA WILL ALLOW A WARM FRONT TO APPROACH
FROM THE SOUTHWEST MONDAY EVENING AND THROUGH THE REGION BY
TUESDAY MORNING.
&&
.NEAR TERM /THROUGH MONDAY/...
UPDATE: RUC AND NAM FORECAST SOUNDINGS INDICATE STRATUS TO DEVELOP
DUE TO STRONG WARM AIR ADVECTION OVER DOWNEAST VERY LATE TONIGHT
AND CONTINUE THROUGH THE DAY. WITH LOW LEVEL TEMPERATURE PROFILE
BETWEEN 0C TO -10C, FREEZING DRIZZLE A POSSIBILITY WITH SURFACE
TEMPERATURES BELOW FREEZING. WITH ISSUE ADVISORY FOR MONDAY
MORNING UNTIL NOONTIME WHEN TEMPERATURES SHOULD RISE ABOVE
FREEZING. ADDITIONAL ADVISORIES MAY BE NEEDED ACROSS CENTRAL AND
NORTHERN SECTION FOR MONDAY NIGHT DUE TO A WINTRY MIX BUT WILL LET
NIGHT CREW TAKE A LOOK AT THAT.
PREV DISCUSSION: HIGH PRESSURE CURRENTLY CRESTING OVER THE STATE WILL
SLOWLY SHIFT OFFSHORE OVERNIGHT. SOUTH FLOW WILL DEVELOP AROUND
THE BACK OF THE HIGH AND CAN ALREADY SEE THE RESULTANT MID AND
HIGH CLOUDS APPROACHING FROM QUEBEC. THESE CLOUDS AND THE LIGHT
SOUTH FLOW MAKE TONIGHT`S TEMPERATURE FORECAST A BIT CHALLENGING.
THESE TWO FACTORS SHOULD LIMIT RADIATIONAL COOLING AND KEEP
TEMPERATURES FAIRLY STEADY OVERNIGHT. THEREFORE EXPECT LOWS TO BE
MUCH WARMER THAN THOSE LAST NIGHT/THIS MORNING...GENERALLY 5 TO 15
ABOVE ZERO. INCREASING SOUTH FLOW WILL ALLOW TEMPS TO RISE TOWARD
DAYBREAK ACROSS FAR DOWNEAST MAINE.
LOW PRESSURE WILL BEGIN TO LIFT OUT OF THE MIDWEST INTO ONTARIO
TOMORROW. WARM ADVECTION PRECIPITATION ASSOCIATED WITH THIS SYSTEM
WILL SLOWLY SPREAD INTO THE FORECAST AREA FROM SOUTH TO NORTH DURING
THE LATE MORNING THROUGH THE AFTERNOON. WITH PLENTY OF COLD AIR IN
PLACE AT THE SURFACE...THE PRECIPITATION WILL START OUT AS A WINTRY
MIX OF SNOW...SLEET...AND FREEZING RAIN. THE WARM AIR STREAMING INTO
THE REGION WILL QUICKLY CHANGE THE MIX OVER TO RAIN OVER THE
SOUTHERN THIRD OF THE STATE LATER IN THE AFTERNOON. COLD AIR HAS A
MUCH FIRMER GRASP ACROSS THE NORTH AND WILL BE MUCH HARDER TO
DISPLACE THERE...SO A MESSY MIX IS EXPECTED TO DEVELOP LATE IN THE
AFTERNOON AND CONTINUE INTO THE EVENING. THE HEAVIEST PRECIPITATION
LOOKS TO HOLD OFF UNTIL MONDAY NIGHT WITH LESS THAN A TENTH OF AN
INCH TO FALL DURING THE AFTERNOON HOURS. THEREFORE ANY SNOW OR ICE
ACCUMULATION WILL ONLY BE AROUND A TRACE OR SO.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
MODELS ARE IN GOOD AGREEMENT WITH WARM ADVCN PRECIP BREAKING OUT
SW TO NE OVR THE FA...PARTICULARLY LATE AT NGT. THE ONLY CHG NOTED
WAS ONSET TIMING WHICH APPEARS TO BE A FEW HRS SLOWER THAN PRIOR
MODEL RUNS AND THE LAST FCST UPDATE. IN THIS UPDATE FOR LATE MON
NGT INTO TUE MORN...WE FIRST INCREASED MAX CATEGORICAL POPS TO
NEAR 100 PERCENT WITH THE CORE OF THE EVENT AND THEN USED THE TIME
SHIFT FUNCTION WITHIN OUR GRID EDITOR TO DELAY ONSET OF PRECIP BY
3 HRS.
AS FOR PRECIP TYPE...CONSENSUS OF MODELS INDICATE A BRIEF MIX OF
LGT SN/PL FOR NRN PTNS AND LGT FZRA AND PL OVR CNTRL AND PERHAPS
INTERIOR DOWNEAST PTNS OF THE FA AT ONSET...CHGNG TO ALL RN S TO
N ACROSS ALL OF THE FA BY 09Z-10Z TUE MORN. WITH FRONTAL INVSN
PRESENT JUST ABV THE SFC...WINDS AT THE SFC SHOULD BE LGT ENOUGH
TO ALLOW AREAS OF FOG TO FORM VERY LATE MON NGT INTO TUE MORN
UPON ONSET OF RAIN OR CHGOVR TO ALL RN ON TOP OF SN PACK. MODELS
INDICATE APPROX 0.30 TO 0.40 LIQ EQUIV WITH THIS EVENT ACROSS THE
REGION BEFORE PRECIP ENDS ACROSS THE S AND WINDS DOWN TO LGT SCT
RN/SN SHWRS ACROSS NRN PTNS OF THE FA. WE INDICATE LESS THAN HALF
INCH OF LGT SN/PL ACCUMULATION OVR FAR NRN AREAS OF THE REGION AND
UPWARDS TO JUST UNDER A TENTH OF AN INCH OF ICE ACCUMULATION OVR N
CNTRL AND FAR NRN AREAS WITH A BRIEF PD OF -FZRA BEFORE ALL PRECIP
CHGS TO RN. BASED ON THIS SCENARIO...A WNTR WX ADV IS POSSIBLE
FOR THE N HLF OF THE FA LATE MON EVE THRU THE OVRNGT HRS.
TEMPS WILL RISE OVRNGT MON REACHING A MAX TUE MORN TO MIDDAY...
THEN SLOWLY FALL OFF BEHIND A WEAK COLD FRONT/OCCLUDED FRONT
TUE AFTN. CLDS AND A CHC OF SN SHWRS HOLD ON ACROSS THE N HALF
OF THE FA TUE NGT INTO WED MORN...WHILE DOWNEAST PTNS OF THE FA
REMAIN MCLR TO PTLY CLDY. AFT ANOTHER NGT OF MILD OVRNGT LOW TEMPS
TUE NGT...MODELS INDICATE A SECONDARY COLD FRONT BRINGING MARGINALLY
COLD ARCTIC AIR BACK INTO THE FA DURING THE DAY WED...WITH ERLY HI
TEMPS ACROSS NRN/WRN PTNS OF THE FA AND SLOWLY FALLING AFTN TEMPS
THERE...WHILE AFTN TEMPS OVR SE PTNS OF THE FA REMAIN STEADY AFT
MIDDAY HIGHS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE EXTENDED MODELS ARE IN GOOD AGREEMENT EARLY IN THE PERIOD. AT
THE START OF THE PERIOD THERE WILL BE A LOW IN THE CANADIAN
MARITIMES...A HIGH PRESSURE RIDGE BUILT ACROSS THE REGION...A NEW
LOW IN MANITOBA...AND A LOW OVER COASTAL TEXAS. BY THURS MORNING
THE LOW OVER MANITOBA MOVES E AND TEXAS MOVE NE INTO MISSISSIPPI.
THE HIGH PRESSURE RIDGE REMAINS OVER THE AREA. BY THURS EVENING
THE CANADIAN LOW MOVES EAST TO JAMES BAY...THE SRN LOW MOVE NE
INTO TN/KY. THE GFS MAINTAINS A LOW ALONG THE MISSISSIPPI COAST.
THE RIDGE OF HIGH PRESSURE SHIFT TO THE EAST. BY FRI MORNING THE
GFS AND ECMWF DIFFER SLIGHTLY ON THE SRN LOW. BOTH MOVE THE
CANADIAN LOW TO THE EAST SIDE OF JAMES BAY WITH A FRONT EXTENDING
SE INTO WRN ME. THE GFS MOVES THE SRN LOW OF THE COAST OF NJ.
FURTHER DEVELOPS THE LOW ALONG THE MISSISSIPPI COAST AND MOVES IT
EAST TO NRN GA. THE ECMWF MOVES THE SRN LOW TO NRN PA. BY FRI
EVENING THE GFS MOVES THE LOW EAST WELL SE OF NOVA SCOTIA...THE
ECMWF MOVE THE LOW TO THE BAY OF FUNDY. BY SAT MORNING THE LOW
WILL BE WELL EAST OF THE AREA INTO THE CANADIAN MARITIMES. BOTH
MODELS SHOW 2NDRY DEVELOPMENT OVER THE GREAT LAKES. THE GFS
DEEPENS THE LOW OVER GA AND MOVES IT TO THE COAST OF NC. BY SAT
EVENING BOTH MODELS ARE INDICATING A BROAD AREA OF LOW PRESSURE
OVER THE LOCAL AREA...THE GFS SHOW TWO DEFINED LOWS. ONE
DEEPENING AND MOVING N...EAST OF CAPE COD. A 2ND LOW DEEPENING
OVER THE ERN GREAT LAKES. THE ECMWF SHOW A LOW OVER SRN QUEBEC. BY
SUN MORNING THE ECMWF MOVES THE LOW EAST OF THE AREA...STARTS
BUILDING HIGHER PRESSURE. THE GFS MOVES THE SRN LOW WELL EAST OF
NOVA SCOTIA...THE NRN LOW INTO QUEBEC PROVINCE WITH A TROUGH
EXTENDING S THROUGH MAINE. BY SUN EVENING THE LOW WILL BE E OF THE
AREA...HIGHER PRESSURE WILL BEGIN TO BUILD INTO THE AREA AND WILL
REMAIN TIL THE END OF THE PERIOD.
LOADED GMOS...ADJUSTED THE SKY AND POP GRIDS TO BETTER SUPPORT
ONE ANOTHER. LOADED NAWAVE 4 FOR SEAS IN THE COASTAL WATERS. PLUS
15 PERCENT FOR WIND GUSTS OVER LAND...20 PERCENT OVER WATER.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
NEAR TERM: VFR CONDITIONS WILL LOWER TO MVFR AROUND 09Z THEN IFR
BY 12Z OVER DOWNEAST TERMINALS. VFR CONDITIONS WILL LOWER TO MVFR
THEN IFR AFTER 18Z ACROSS NORTHERN TERMINALS.
SHORT TERM: MVFR SC/ST CLD CVR XPCTD ACROSS THE TAF SITES MON EVE
EVEN BEFORE PRECIP ARRIVES...THEN LOWERING TO IFR AND EVENTUALLY
LIFR IN PRECIP AND FOG LATE MON NGT INTO ERLY TUE MORN. CONDITIONS
IMPROVE TO VFR DOWNEAST TAF SITES AND MVFR NRN SITES BY MIDDAY TUE
BEHIND A COLD FRONT...AND CONT SO INTO WED MORN BEFORE ALL TAF
SITES BECOME VFR WED AFT. ALL SITES CONT VFR WED NGT THRU MOST
OF THU NGT...BEFORE LOWERING TO LOW MVFR OR IFR IN POSSIBLE SN
FRI.
&&
.MARINE...
NEAR TERM: HIGH PRESSURE BRIDGING OVER THE WATERS WILL KEEP WINDS
AND WAVES WELL BELOW SCA CRITERIA OVERNIGHT. SOUTH WINDS WILL
DEVELOP LATE TONIGHT AND GRADUALLY INCREASE TO 10 TO 20 KT WITH A
FEW HIGHER GUSTS BY MONDAY AFTERNOON. WAVES WILL INCREASE AS
WELL...TO AROUND 4 FT.
SHORT TERM: SCA CONDITIONS XPCTD AHEAD OF THE WARM FRONT MON NGT
INTO ERLY TUE MORN AND POSSIBLY AGAIN WED AFTN THRU WED NGT BEHIND
A SECONDARY COLD FRONT. NO HDLNS ANTICIPATED ATTM THU AND FRI. WE
USED A BLEND OF 12Z GFS40 AND NAM40 WINDS AND BLENDED WW3 WV HTS
WITH SLIGHTLY HIER SWAN GFS WV HTS FOR THIS PTN OF THE FCST.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY FROM 5 AM TO NOON EST MONDAY FOR
MEZ015>017-029-030.
MARINE...NONE.
&&
$$
NEAR TERM...FOSTER/HASTINGS
SHORT TERM...VJN
LONG TERM...NORTON
AVIATION...FOSTER/HASTINGS
MARINE...FOSTER/HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1201 PM EST SAT JAN 21 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE GULF OF MAINE TODAY. HIGH
PRESSURE WILL THEN BUILD ACROSS THE REGION SUNDAY AND MOVE EAST OF
THE AREA EARLY MONDAY.
&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE2: WITH SNOW JUST WEST OF OUR FORECAST AREA, WILL INCREASE POPS TO
LIKELY ALONG THE COAST FOR THE REMAINDER OF THIS AFTERNOON. ANY
SNOW ACCUMULATION STILL APPEARS TO BE LESS THAN AN INCH.
UPDATE1: HRRR MODEL STILL INDICATING NORTHERN EDGE OF SNOW WILL
MOVE ACROSS DOWNEAST THIS AFTERNOON WITH A PERIOD OF LIGHT SNOW SO
WILL KEEP POPS GOING FOR DOWNEAST TODAY. ANY SNOW ACCUMULATION
WILL BE LESS THAN AN INCH.
PREV DISC: LOW PRESSURE WILL TRACK SOUTH OF NEW ENGLAND TODAY. THE
PRECIPITATION FROM THIS SYSTEM IS ONLY EXPECTED TO EFFECT THE
SOUTH. HAVE USED A BLEND OF THE NAM12...GFS40 AND SREF FOR POPS.
WILL ADJUST THIS BLEND MANUALLY TO KEEP LOWER POPS FURTHER SOUTH.
HAVE USE A BLEND OF NAM12 AND GFS40 FOR WIND. HIGH PRESSURE WILL
BUILD IN FROM THE NORTHWEST SUNDAY. FOR TEMPERATURE AND DEW POINT
WILL USE GMOS AND ADJUST LOW TEMPERATURE LOWER SUNDAY MORNING TO
ACCOUNT FOR RADIATIONAL COOLING. FOR QPF HAVE BLENDED THE NAM12
AND GFS40.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A THAW LOOKS TO BE IN ORDER COME MONDAY W/LOW PRES MOVING THROUGH
THE WESTERN QUEBEC PROVINCE.
A NICE DAY IS IN STORE FOR SUNDAY W/A A GOOD DEAL OF SUNSHINE AS
HIGH PRES SETTLES RIGHT ACROSS THE STATE. TEMPERATURES WILL BE
WARMER THAN THEY WERE SATURDAY HITTING THE MID/UPPER TEENS NORTH
AND LOW TO MID 20S ACROSS THE CENTRAL AND DOWNEAST REGION. HIGH
PRES WILL SLIDE E SUNDAY NIGHT W/A RETURN FLOW FROM THE ESE
BEGINNING TO SETUP. HIGH CLOUDINESS IS SHOWN BY THE GFS AND THE
NAM TO MOVE ACROSS THE REGION SUNDAY NIGHT AS WAA BEGINS TO SET
UP. TEMPERATURES WILL DROP BACK IN THE EVENING AND THEN ARE SHOWN
TO LEVEL OFF BEFORE RISING EARLY MONDAY MORNING. ATTM, STAYED
CLOSE TO THE DAYCREW/S ASSESSMENT OF SINGLE NUMBERS ACROSS THE
NORTHERN AND WESTERN SECTIONS AND LOW TO MID TEENS FOR THE CENTRAL
AND DOWNEAST REGIONS. THIS WILL NEED TO BE LOOKED AT AGAIN AS ANY
PROLONGED CLEARING WILL ALLOW FOR TEMPERATURES TO FALL OFF MORE
BEFORE LEVELING OFF.
INCREASING CLOUDS FOR MONDAY W/A SSE FLOW SETTING UP AND MOISTURE
GETTING PULLED NORTHWARD. STRATUS LOOKS LIKE IT COULD ADVECT IN
W/THIS SETUP. ECMWF HOLDS ON TO LLVL COLD AIR LONGER W/DAMMING
ACROSS THE ENE SECTIONS OF THE CWA. THE NAM AND THE CANADIAN
HEMISPHERIC INDICATE THIS TO BE THE CASE AS WELL. THE GFS BREAKS
DOWN THE DAMMING QUICKER. THEREFORE, DECIDED TO CUT BACK MAXES ON
MONDAY W/THE SETUP PLUS WARMING TENDS TO HOLD BACK A BIT W/A SE
FLOW GETTING STARTED(HISTORICALLY SPEAKING). PRECIP CHANCES WERE
HELD BACK SOME W/RIDGE HOLDING IN LONGER. LOOKS LIKE SOME MIX OF
RAIN/SNOW AND SLEET INITIALLY LATE MONDAY ACROSS THE NORTH AND
WEST W/RAIN OVER THE DOWNEAST AND POINTS SOUTH. TEMPERATURES WILL
CONTINUE TO SLOWLY RISE MONDAY NIGHT AND THIS WILL BE ADDRESSED
BELOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE MAIN CHALLENGE THIS TERM WILL BE TEMPERATURES AND PRECIP TYPE
EARLY IN THE TERM.
OCCLUSION IS SHOWN BY THE LONG RANGE GUIDANCE INCLUDING THE
CANADIAN HEMISPHERIC TO LIFT NORTHWARD MONDAY NIGHT AND SWING
ACROSS THE REGION ON TUESDAY. THE NAM/ECMWF SHOW A WEAK LOW
DEVELOPING ON THE OCCLUSION AND MOVING ACROSS EASTERN MAINE. THIS
COULD ENHANCE PRECIP AND POSSIBLY CUT OFF SIGNIFICANT WARMING
WHILE THE CANADIAN HEMISPHERIC HINTS AT SOMETHING SIMILAR BUT IS
FURTHER WEST WHICH WOULD ALLOW FOR MORE WARMER AIR TO BE PULLED
NORTHWARD. THE GFS AND ITS ENSEMBLE MEAN KEEP THE OCCLUSION
SWEEPING THROUGH THE REGION ON TUESDAY. DAYCREWS POPS LOOKED GOOD
AND MODIFICATIONS MADE ONLY FOR PLACEMENT AND BROUGHT THE VALUES
UP SOME BUT STILL IN THE LIKELY TO CATEGORICAL RANGE. SOME SLEET
AND RAIN POSSIBLE ACROSS THE FAR NORTH EARLY MONDAY EVENING BUT
THE COLUMN SHOULD BE WARM ENOUGH TO ALLOW FOR RAIN. AN INTERESTING
NOTE IS THAT THE HEMISPHERIC GUIDANCE SHOWS 40S AND 50S TUESDAY
AFTERNOON. THIS IS THE ONLY GUIDANCE THAT IS SHOWING THIS TO BE
THE CASE. A BLEND OF THE GMOS AND GFS WAS USED FOR THE TEMPERATURES
WHICH INDICATE A WARMER SCENARIO FOR TUESDAY W/TEMPERATURES
HITTING THE MID AND UPPER 30S NORTH AND WEST AND 40S CENTRAL AND
DOWNEAST. THE FRONT CLEARS THE REGION BY TUESDAY EVENING W/THE
GRADUAL COOL DOWN AND WHATEVER PRECIP IS LEFTOVER TRANSITIONING TO
SNOW SHOWERS MAINLY NORTH & WEST. HELD BACK THE COOLING FOR ABOUT
6 HRS AS PAST EVENTS SIMILAR TO THIS SHOW MODELS TO BE TOO FAST
W/BRINGING THE COLDER AIR BACK IN BEHIND THE OCCLUSION. UPPER TROF
WILL NEED TO MOVE THROUGH FOR THAT TO HAPPEN. GMOS/GFS TEMPERATURES
WERE BLENDED FOR TUESDAY NIGHT AS WELL.
THE ASSOCIATED COLD FRONT WILL MAKE ITS WAY ACROSS THE CWA ON
WEDNESDAY W/MUCH COLDER TEMPERATURES FOR MID TO LATE WEEK AS
ADVERTISED BY THE GFS AND ECMWF. GMOS WAS USED FROM WEDNESDAY
ONWARD BUT PULLED BACK POPS TO BELOW 20% THURSDAY INTO FRIDAY
W/HIGH PRES BUILDING ACROSS THE REGION. ECMWF BRINGS A LOW ACROSS
THE GULF OF MAINE LATE NEXT FRIDAY W/AN INVERTED TROF HANGING BACK
ACROSS THE REGION SIMILAR TO THIS PASS EVENT YESTERDAY(FRIDAY1/20).
THIS WOULD MEAN POTENTIAL SNOW FOR THE CWA. THE ECMWF IS THE ONLY
GUIDANCE SHOWING THIS AS THE GFS AND ITS ENSEMBLES SHOW THE LOW TO
DEVELOP WELL SOUTH OF THE CWA. STILL PLENTY OF TIME TO LOOK AT
THIS AS THIS IS DAY 7!.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MAINLY VFR CONDITIONS TODAY AND TONIGHT EXCEPT FOR A
PERIOD OF MVFR IN LIGHT SNOW ACROSS DOWNEAST TERMINALS LATE
MORNING INTO EARLY AFTERNOON.
SHORT TERM: VFR FOR SUNDAY AND THEN POTENTIAL FOR MVFR/IFR ON
MONDAY W/SSE FLOW SETTING UP W/MOISTURE GETTING PULLED IN FROM THE
ATLC OCEAN. MONDAY NIGHT INTO TUESDAY LOOK TO BE IFR AND EVEN LIFR
AT LEAST EARLY IN THE DAY. LLWS ALSO A POSSIBILITY EARLY TUESDAY.
&&
.MARINE...
NEAR TERM: AS LOW PRESSURE MOVES SOUTHEAST OF THE WATERS, MAY
HAVE A PERIOD OF SCA WINDS ON THE BACK SIDE OF THE LOW PRESSURE
TONIGHT MAINLY OVER OUR OUTER WATERS.
SHORT TERM: SCA CONDITIONS BY MONDAY W/POTENTIAL FOR A BRIEF
PERIOD OF GALES EARLY TUESDAY W/THE OCCLUSION. USED THE NAM12 AND
GFS THROUGH EARLY TUESDAY WHICH SUPPORTS GUSTS HITTING 35+ KTS
FROM 12-18Z TUESDAY AS LLVL JET OF 50 KTS IS SHOWN TO PASS OVER
THE WATERS. HELD ONTO THE DAYCREWS WAVE HEIGHTS OF INCREASING SEAS
TO 10-13FT BY TUESDAY W/SSE FLOW. FOLLOWED WNAWAVE FROM TUESDAY
NIGHT INTO WEDNESDAY SHOWING A DECREASING TREND IN SEAS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST SUNDAY
FOR ANZ050-051.
&&
$$
NEAR TERM...FOSTER/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...FOSTER/MIGNONE
MARINE...FOSTER/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
931 AM EST SAT JAN 21 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE GULF OF MAINE TODAY. HIGH
PRESSURE WILL THEN BUILD ACROSS THE REGION SUNDAY AND MOVE EAST OF
THE AREA EARLY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: HRRR MODEL STILL INDICATING NORTHERN EDGE OF SNOW WILL MOVE
ACROSS DOWNEAST THIS AFTERNOON WITH A PERIOD OF LIGHT SNOW SO WILL
KEEP POPS GOING FOR DOWNEAST TODAY. ANY SNOW ACCUMULATION WILL BE
LESS THAN AN INCH.
PREV DISC: LOW PRESSURE WILL TRACK SOUTH OF NEW ENGLAND TODAY. THE
PRECIPITATION FROM THIS SYSTEM IS ONLY EXPECTED TO EFFECT THE
SOUTH. HAVE USED A BLEND OF THE NAM12...GFS40 AND SREF FOR POPS.
WILL ADJUST THIS BLEND MANUALLY TO KEEP LOWER POPS FURTHER SOUTH.
HAVE USE A BLEND OF NAM12 AND GFS40 FOR WIND. HIGH PRESSURE WILL
BUILD IN FROM THE NORTHWEST SUNDAY. FOR TEMPERATURE AND DEW POINT
WILL USE GMOS AND ADJUST LOW TEMPERATURE LOWER SUNDAY MORNING TO
ACCOUNT FOR RADIATIONAL COOLING. FOR QPF HAVE BLENDED THE NAM12
AND GFS40.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A THAW LOOKS TO BE IN ORDER COME MONDAY W/LOW PRES MOVING THROUGH
THE WESTERN QUEBEC PROVINCE.
A NICE DAY IS IN STORE FOR SUNDAY W/A A GOOD DEAL OF SUNSHINE AS
HIGH PRES SETTLES RIGHT ACROSS THE STATE. TEMPERATURES WILL BE
WARMER THAN THEY WERE SATURDAY HITTING THE MID/UPPER TEENS NORTH
AND LOW TO MID 20S ACROSS THE CENTRAL AND DOWNEAST REGION. HIGH
PRES WILL SLIDE E SUNDAY NIGHT W/A RETURN FLOW FROM THE ESE
BEGINNING TO SETUP. HIGH CLOUDINESS IS SHOWN BY THE GFS AND THE
NAM TO MOVE ACROSS THE REGION SUNDAY NIGHT AS WAA BEGINS TO SET
UP. TEMPERATURES WILL DROP BACK IN THE EVENING AND THEN ARE SHOWN
TO LEVEL OFF BEFORE RISING EARLY MONDAY MORNING. ATTM, STAYED
CLOSE TO THE DAYCREW/S ASSESSMENT OF SINGLE NUMBERS ACROSS THE
NORTHERN AND WESTERN SECTIONS AND LOW TO MID TEENS FOR THE CENTRAL
AND DOWNEAST REGIONS. THIS WILL NEED TO BE LOOKED AT AGAIN AS ANY
PROLONGED CLEARING WILL ALLOW FOR TEMPERATURES TO FALL OFF MORE
BEFORE LEVELING OFF.
INCREASING CLOUDS FOR MONDAY W/A SSE FLOW SETTING UP AND MOISTURE
GETTING PULLED NORTHWARD. STRATUS LOOKS LIKE IT COULD ADVECT IN
W/THIS SETUP. ECMWF HOLDS ON TO LLVL COLD AIR LONGER W/DAMMING
ACROSS THE ENE SECTIONS OF THE CWA. THE NAM AND THE CANADIAN
HEMISPHERIC INDICATE THIS TO BE THE CASE AS WELL. THE GFS BREAKS
DOWN THE DAMMING QUICKER. THEREFORE, DECIDED TO CUT BACK MAXES ON
MONDAY W/THE SETUP PLUS WARMING TENDS TO HOLD BACK A BIT W/A SE
FLOW GETTING STARTED(HISTORICALLY SPEAKING). PRECIP CHANCES WERE
HELD BACK SOME W/RIDGE HOLDING IN LONGER. LOOKS LIKE SOME MIX OF
RAIN/SNOW AND SLEET INITIALLY LATE MONDAY ACROSS THE NORTH AND
WEST W/RAIN OVER THE DOWNEAST AND POINTS SOUTH. TEMPERATURES WILL
CONTINUE TO SLOWLY RISE MONDAY NIGHT AND THIS WILL BE ADDRESSED
BELOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE MAIN CHALLENGE THIS TERM WILL BE TEMPERATURES AND PRECIP TYPE
EARLY IN THE TERM.
OCCLUSION IS SHOWN BY THE LONG RANGE GUIDANCE INCLUDING THE
CANADIAN HEMISPHERIC TO LIFT NORTHWARD MONDAY NIGHT AND SWING
ACROSS THE REGION ON TUESDAY. THE NAM/ECMWF SHOW A WEAK LOW
DEVELOPING ON THE OCCLUSION AND MOVING ACROSS EASTERN MAINE. THIS
COULD ENHANCE PRECIP AND POSSIBLY CUT OFF SIGNIFICANT WARMING
WHILE THE CANADIAN HEMISPHERIC HINTS AT SOMETHING SIMILAR BUT IS
FURTHER WEST WHICH WOULD ALLOW FOR MORE WARMER AIR TO BE PULLED
NORTHWARD. THE GFS AND ITS ENSEMBLE MEAN KEEP THE OCCLUSION
SWEEPING THROUGH THE REGION ON TUESDAY. DAYCREWS POPS LOOKED GOOD
AND MODIFICATIONS MADE ONLY FOR PLACEMENT AND BROUGHT THE VALUES
UP SOME BUT STILL IN THE LIKELY TO CATEGORICAL RANGE. SOME SLEET
AND RAIN POSSIBLE ACROSS THE FAR NORTH EARLY MONDAY EVENING BUT
THE COLUMN SHOULD BE WARM ENOUGH TO ALLOW FOR RAIN. AN INTERESTING
NOTE IS THAT THE HEMISPHERIC GUIDANCE SHOWS 40S AND 50S TUESDAY
AFTERNOON. THIS IS THE ONLY GUIDANCE THAT IS SHOWING THIS TO BE
THE CASE. A BLEND OF THE GMOS AND GFS WAS USED FOR THE TEMPERATURES
WHICH INDICATE A WARMER SCENARIO FOR TUESDAY W/TEMPERATURES
HITTING THE MID AND UPPER 30S NORTH AND WEST AND 40S CENTRAL AND
DOWNEAST. THE FRONT CLEARS THE REGION BY TUESDAY EVENING W/THE
GRADUAL COOL DOWN AND WHATEVER PRECIP IS LEFTOVER TRANSITIONING TO
SNOW SHOWERS MAINLY NORTH & WEST. HELD BACK THE COOLING FOR ABOUT
6 HRS AS PAST EVENTS SIMILAR TO THIS SHOW MODELS TO BE TOO FAST
W/BRINGING THE COLDER AIR BACK IN BEHIND THE OCCLUSION. UPPER TROF
WILL NEED TO MOVE THROUGH FOR THAT TO HAPPEN. GMOS/GFS TEMPERATURES
WERE BLENDED FOR TUESDAY NIGHT AS WELL.
THE ASSOCIATED COLD FRONT WILL MAKE ITS WAY ACROSS THE CWA ON
WEDNESDAY W/MUCH COLDER TEMPERATURES FOR MID TO LATE WEEK AS
ADVERTISED BY THE GFS AND ECMWF. GMOS WAS USED FROM WEDNESDAY
ONWARD BUT PULLED BACK POPS TO BELOW 20% THURSDAY INTO FRIDAY
W/HIGH PRES BUILDING ACROSS THE REGION. ECMWF BRINGS A LOW ACROSS
THE GULF OF MAINE LATE NEXT FRIDAY W/AN INVERTED TROF HANGING BACK
ACROSS THE REGION SIMILAR TO THIS PASS EVENT YESTERDAY(FRIDAY1/20).
THIS WOULD MEAN POTENTIAL SNOW FOR THE CWA. THE ECMWF IS THE ONLY
GUIDANCE SHOWING THIS AS THE GFS AND ITS ENSEMBLES SHOW THE LOW TO
DEVELOP WELL SOUTH OF THE CWA. STILL PLENTY OF TIME TO LOOK AT
THIS AS THIS IS DAY 7!.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MAINLY VFR CONDITIONS TODAY AND TONIGHT EXCEPT FOR A
PERIOD OF MVFR IN LIGHT SNOW ACROSS DOWNEAST TERMINALS LATE
MORNING INTO EARLY AFTERNOON.
SHORT TERM: VFR FOR SUNDAY AND THEN POTENTIAL FOR MVFR/IFR ON
MONDAY W/SSE FLOW SETTING UP W/MOISTURE GETTING PULLED IN FROM THE
ATLC OCEAN. MONDAY NIGHT INTO TUESDAY LOOK TO BE IFR AND EVEN LIFR
AT LEAST EARLY IN THE DAY. LLWS ALSO A POSSIBILITY EARLY TUESDAY.
&&
.MARINE...
NEAR TERM: AS LOW PRESSURE MOVES SOUTHEAST OF THE WATERS, MAY
HAVE A PERIOD OF SCA WINDS ON THE BACK SIDE OF THE LOW PRESSURE
TONIGHT MAINLY OVER OUR OUTER WATERS.
SHORT TERM: SCA CONDITIONS BY MONDAY W/POTENTIAL FOR A BRIEF
PERIOD OF GALES EARLY TUESDAY W/THE OCCLUSION. USED THE NAM12 AND
GFS THROUGH EARLY TUESDAY WHICH SUPPORTS GUSTS HITTING 35+ KTS
FROM 12-18Z TUESDAY AS LLVL JET OF 50 KTS IS SHOWN TO PASS OVER
THE WATERS. HELD ONTO THE DAYCREWS WAVE HEIGHTS OF INCREASING SEAS
TO 10-13FT BY TUESDAY W/SSE FLOW. FOLLOWED WNAWAVE FROM TUESDAY
NIGHT INTO WEDNESDAY SHOWING A DECREASING TREND IN SEAS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST SUNDAY
FOR ANZ050-051.
&&
$$
NEAR TERM...FOSTER/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...FOSTER/MIGNONE
MARINE...FOSTER/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
951 AM EST SAT JAN 21 2012
.SYNOPSIS...
WHATS LEFT OF THE WINTRY MIX WILL END BY NOONTIME AS LOW PRESSURE
EXITS EAST PAST THE WEST VIRGINIA MOUNTAINS. HIGH PRESSURE, COMING
EAST FROM WISCONSIN, WILL PROVIDE A DRY BREAK THIS AFTERNOON INTO
SUNDAY EVENING. A COLD FRONT, COMING EAST FROM THE ROCKIES, WILL
THEN BRING RAIN SHOWERS LATE SUNDAY NIGHT AND MONDAY, FOLLOWED
SCATTERED SNOW SHOWERS LATE MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
PER RECENT SURFACE AND RADAR DATA HAVE FORECASTED A SLIGHTLY
FASTER END OF THE WINTRY MIX. HENCE HAVE DROPPED ADDITIONAL
COUNTIES FROM WINTER WEATHER HEADLINES, ONLY LEAVING THE MOUNTAINS
WITH HEADLINES UNTIL 12 PM.
PER RECENT SATELLITE DATA AND HRRR MODEL OUTPUT, HAVE FORECASTED
THINNING CLOUDS IN WAKE OF EXITING LOW PRESSURE SYSTEM. HAVE
MAINTAINED A SLOW DECREASE IN CLOUD COVERAGE AS NAM MODEL PROFILES
SUGGEST STRATOCUMULUS CAN REMAIN IN A THIN SATURATED LAYER BENEATH
A STRENGTHENING SUBSIDENCE INVERSION NEAR 4 KFT AGL.
HAVE CUT TEMPERATURE INCREASE THIS AFTERNOON, INFLUENCED BY RECENT
HRRR AND GFS LAMP MODEL OUTPUT, TO PRETTY MUCH MAINTAIN STEADY
TEMPERATURES THIS AFTERNOON. PART OF THIS IS DUE TO COLD ADVECTION
AND LINGERING CLOUDS, AND PART DUE TO REFRIGERATING, REFLECTIVE
EFFECTS OF FRESH SNOW AND ICE COVER.
FOR TONIGHT, EXPECT CLOUDS TO DECREASE. HAVE LOWERED LOW
TEMPERATURES DUE TO EXPECTED INCREASE IN RADIATIVE COOLING ABOVE
FRESH SNOW AND ICE COVER.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW HIGH PRESSURE, COMING
EAST FROM THE PLAINS, WILL PROVIDE A DRY BREAK INTO SUNDAY
EVENING. THEN EXPECT LOW PRESSURE, MOVING EAST ACROSS SOUTHERN
CANADA, TO DRIVE A COLD FRONT THROUGH THE UPPER OHIO VALLEY MONDAY
AFTERNOON. THE FRONTAL BAND OF SHOWERS SHOULD SPREAD EASTWARD
THROUGH THE AREA, STARTING LATE SUNDAY NIGHT.
FORECASTED TEMPERATURES, USING BLEND OF NAM AND GFS MOS, TO WARM
ABOVE FREEZING SUNDAY AND STAY ABOVE FREEZING INTO LATE MONDAY.
HIGHS MONDAY CAN BE 10 DEGREES WARMER THAN NORMAL.
PREFRONTAL SOUTHEAST WINDS MAY GUST OVER 30 MPH DOWNWIND FROM THE
MOUNTAINS SUNDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A LOW PRESSURE SYSTEM WILL EXIT THE GREAT LAKES REGION AND MOVE INTO
SOUTHERN QUEBEC BY TUESDAY. SHOWERS WILL TAPER OFF TUESDAY AND COULD
CHANGE OVER TO SCATTERED SNOW SHOWERS BEFORE ENDING IN THE
AFTERNOON. A RIDGE OF HIGH PRESSURE SHOULD PROVIDE DRY WEATHER ON
WEDNESDAY.
MEDIUM RANGE MODELS SHOW A NORTHERN BRANCH SHORT WAVE TROUGH MOVING
EAST INTO THE GREAT LAKES REGION BY THURSDAY. MEANWHILE...A SOUTHERN
BRANCH CLOSED LOW MEANDERS GENERALLY EASTWARD ACROSS TX AND INTO THE
LOWER MS VALLEY LATE IN THE WEEK. MODELS DIFFER ON EVOLUTION AND
TRACK OF ASSOCIATED SURFACE LOWS THURSDAY INTO FRIDAY. OUR PLAN IS
TO STICK WITH HPC GUIDANCE WITH CHANCE POPS BEGINNING WEDNESDAY
NIGHT AND CONTINUING INTO FRIDAY.
TEMPERATURES ARE FORECAST TO REMAIN GENERALLY BETWEEN 5 AND 10
DEGREES ABOVE NORMAL DURING THE EXTENDED PERIOD.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
VISIBILITIES HAVE IMPROVED TO MVFR IN LIGHT FOG IN WAKE OF ENDING
PRECIPITATION, AND WILL BECOME UNRESTRICTED THIS AFTERNOON.
POST SYSTEM COOLING, COMBINED WITH SUBSIDENCE ALOFT, WILL MAINTAIN
A STRATOCUMULUS DECK INTO EARLY EVENING. CEILINGS WILL SLOWLY LIFT
FROM IFR LEVELS TO MVFR LEVELS THIS AFTERNOON.
SURFACE WINDS WILL BE FROM THE NORTH NEAR 10 KTS THIS AFTERNOON,
THEN BECOME NORTHEAST NEAR 5 KTS TONIGHT.
EXPECT VFR LATE TONIGHT, BUT NAM MODEL PROFILES SHOW STRONG
SURFACE INVERSION DUE TO RADIATIVE EFFECTS OVER FRESH SNOW AND ICE
COVER. SO HAVE SOME CONCERN OF EARLY MORNING FOG WITH RESTRICTIONS
DEVELOPING, BUT NOT CONFIDENT TO INCLUDE IN TAF FORECAST.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
VFR INTO EARLY SUNDAY NIGHT. COLD FRONTAL BANDS OF RAIN SHOWERS
WITH LIKELY RESTRICTIONS LATE SUNDAY NIGHT INTO MONDAY NIGHT. POST
FRONTAL SCATTERED SNOW SHOWERS MAY CAUSE LINGERING RESTRICTIONS
INTO TUESDAY. VFR WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL NOON EST TODAY FOR MDZ001.
OH...NONE.
PA...WINTER STORM WARNING UNTIL NOON EST TODAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
713 AM EST SAT JAN 21 2012
.SYNOPSIS...
LOW PRESSURE CENTERED OVER THE TENNESSEE VALLEY WILL TRACK EAST
TODAY AND MOVE VERY SLOW THROUGH THE MID ATLANTIC REGION. THE
ASSOCIATED COLD FRONT WILL PUSH SOUTHEAST LATE THIS AFTERNOON AND
EVENING AS STRONG HIGH PRESSURE BUILDS SOUTH FROM NEW ENGLAND
OVERNIGHT INTO SUNDAY. A STRONGER COLD FRONT WILL AFFECT THE AREA
ON MONDAY...FOLLOWED BY HIGH PRESSURE BUILDING OVER THE SOUTHEAST
STATES TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FCST TO ADD WINTER WX ADSY FOR SOME OF THE NW
COUNTIES...AS AREA OF MODERATE PRECIPITATION IS OVERSPREADING THIS
AREA...AND SHOULD COINCIDE WITH TEMPS 32 F OR COLDER FOR ABOUT 3
HRS. USING LATEST RUC SFC- WET BULB TEMPERATURES SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT OBS...LOW LEVEL COLD AIR IS VERY SHALLOW...SUCH
THAT EVEN 1000-850 MB THICKNESSES ARE VERIFYING TOO WARM.
OTHERWISE...AREAS FARTHER TO THE SE OF THE ADVSY SHOULD ENCOUNTER
JUST RAIN FOR THE REST OF THE DAY...6 AM OBS SHOW DEW PT AT 34 F
AT RIC...SO THAT EVAPORATIVE COLUMN COOLING WILL NOT LOWER THE
TEMPS AS THEY DID LAST EVENING...SOME SPOTTY -FZRA MAY BE
POSSIBLE OVER EXTREME NW PORTIONS OF THE COUNTIES BORDERING THE
ADSY BUT ANY ACCUMULATION IS NOT LIKELY...AS SFC TEMPS SHOULD BE
ABOVE FREEZING SHORTLY.
LATER TODAY...RA/SHRA SHOULD COVER ALL AREAS BY LATE MORNING OR EARLY
AFTN. SOUTH OF THE BOUNDARY...ADDED ISO TSTMS FOR THE AFTN IN SE
VA/NE NC WHERE TEMPS RISE INTO THE UPR 50S TO MID 60S W/ DEW PTS
IN THE 50S. CURRENT AREA OF CONVECTION OVER KY/TN WILL LIKELY
BREAK APART WHEN IT INTERACTS W/ THE MTNS BUT MAY RE- GENERATE
THIS AFTN. ONLY MINIMAL INSTABILITY BUT THERE IS DECENT SHEAR SO
AN ISO STRONGER STORM IS POSSIBLE/MAIN THREAT BEING STRONG WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...MODELS AGREE THAT N/NE FLOW WILL OVERSPREAD THE ENTIRE
CWA BY 00Z...AS SFC LOW PUSHES OFF THE NC COAST. STILL LOTS OF LOW
LEVEL MOISTURE...BUT MID LEVEL DRYING FROM THE NORTH SHOULD BRING
AN END TO MOST OF THE PRECIP BETWEEN 00-03Z EXCEPT IN NE NC WHERE
IT LINGERS A FEW HRS LONGER. WV SATELLITE SUGGEST STRONG AREA OF
MID-UPPER CONFLUENCE OVER HUDSON BAY WILL SLIDE SE...ALLOWING WITH
A 1035 MB SFC HIGH TO BUILDING INTO ERN NY STATE/NEW ENGLAND. COLD
AIR FILTERS SOUTH ONCE AGAIN...BUT PRETTY GOOD CONSENSUS THAT
THIS WILL HOLD OFF UNTIL AFTER BULK OF PRECIP ENDS...I.E. PRECIP
ENDS BEFORE PTYPE CONCERNS BECOME A MAJOR ISSUE. FOR NOW WILL
MENTION POTENTIAL FOR FREEZING DRIZZLE ACRS NRN ZONES BEGINNING
AFTER ABOUT 03Z. LOWS IN THE UPR 20S NORTH...UPR 30S S.
SUN/SUN NIGHT...LOOKS TO BE A COLD DAY ON SUNDAY WITH NE FLOW. ONLY
CONCERN WOULD BE FOR FREEZING DRIZZLE IN THE MORNING OVER CENTRAL
VA...INCLUDING METRO RICHMOND AND AREAS ON NW AS LOW LEVELS REMAIN
BELOW CRITICAL THRESHOLDS FOR FROZEN PRECIP. VERY DRY ALOFT
HOWEVER...SO THIS WOULD BE NOTHING MORE THAN FREEZING DRIZZLE...WILL
MAKE AN HWO MENTION FOR NOW. SHOULD BE WARM ENOUGH FOR JUST -RADZ
BY AFTN (EXCEPT COULD BE CLOSE IN THE COLDER FAR NW ZONES. DOUBT
WE`LL SEE ANY BREAKS IN THE CLOUD COVER AS LOW LEVEL INVERSION
WILL BE DIFFICULT TO MIX OUT...PERHAPS A FEW PEEKS OF SUN IN THE
MORNING OVER THE FAR NORTH CLOSEST TO THE SFC HIGH. BREEZY
CONDITIONS ALONG THE COAST. FAVOR THE COLDER MET NUMBERS FOR
HIGHS...BASED ON LIMITED MIXING AND A LOW OVC...HIGHS RANGING FROM
THE UPPER 40S FAR SE VA/NE NC...MID- UPPER 30S NW ZONES. TEMPS
RISE OVERNIGHT SUNDAY NIGHT...AS SFC HIGH OVER NEW ENGLAND
RETREATS OFF TO THE NE...FOLLOWED BY SIGNIFICANT WARM-UP ON MON
AHEAD OF THE NEXT SYSTEM. FAVOR THE WARMER MAV VALUES ON MON W/
SSW FLOW BY LATE MORNING AFTN...HIGHS GENLY IN THE UPR 50S NW
(WHERE PRECIP COMES IN EARLIER) TO THE MID- UPR 60S SE. CHC TO
LIKELY POPS FOR SHOWERS ALL AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A SERIES OF WAVES WILL PASS NORTH OF THE FA DURING THE LONG TERM
PERIOD DRAGGING COLD FRONTS AND PERIODS PRECIP THROUGH THE AREA.
RAIN WILL BEGIN TO IMPACT THE AREA MONDAY AS AN UPPER LEVEL WAVE
PASSES OVER NORTHERN MICHIGAN. THE ASSOCIATED COLD FRONT CROSSES THE
AREA BRINGING A PERIOD OF RAIN AND A WIND SHIFT FROM THE S TO N. THE
MODELS VARY A BIT WITH THE STRENGTH OF THE SYSTEM...AND HAVE LEANED
TOWARD THE WEAKER ECMWF. BUT...IF THE GFS VERIFIES THERE COULD BE A
COUPLE TSTMS THAT DEVELOP IN NE NC AND SE VA. BENIGN WX PREVAILS AS
HIGH PRESSURE BUILDS OVER THE AREA TUESDAY NIGHT AND SLIDES OFF THE
COAST BY THURSDAY EVENING. THE NEXT SYSTEM LOOKS TO IMPACT THE AREA
FRIDAY MORNING AS A WARM FRONT BRINGS RAIN INTO THE AREA...FOLLOWED
BY A COLD FRONT THAT WILL BRING ANOTHER ROUND OF RAIN LATE FRI/EARLY
SAT. AGAIN THERE IS A BIT OF DISAGREEMENT WITH THE MODEL TIMING OF
THIS EVENT. THE ECMWF PROGRESSES THE UPPER LEVEL SYSTEM EAST MUCH
MORE QUICKLY THAN THE GFS. BEING THIS FAR OUT IN THE FORECAST...JUST
TRIED TO BLEND THE TIMING OF THE SCENARIOS TOGETHER.
EXPECT A BIT OF A ROLLER COASTER AS FAR AS TEMPS GO DURING THE
PERIOD. WITH THE APPROACH THE SYSTEM MONDAY...EXPECT HIGHS IN THE
MID 60S NORTH TO UPPER 60S SOUTH. AS THE FRONT CLEARS THE AREA
MILDER TEMPS WILL PREVAIL WITH HIGHS IN THE MID 50S TO 60 FOR TUES
AND WED. A WARMER DAY FOLLOWS ON THUR AS WINDS TURN SOUTH AHEAD OF
THE NEXT FRONT. LOWS WILL BE IN THE LOW 40S TUES...FALLING TO THE
LOW AND MID 30S FOR WED AND THUR...WARMING INTO THE MID 40S FOR FRI
AND SAT.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
ONGOING LIGHT TO MOD PCPN THIS MORNING IN ASSOCIATION WITH WEAK
ISENTROPIC LIFT. MVFR/TEMPO IFR CONDS ACROSS ALL BUT FAR SE
TERMINALS AS OF 7A. CONDITIONS DETERIORATING AS EXPECTED OVER FAR
NORTHERN ZONES...WITH IFR CONDS EXPECTED AT NORTHERN TERMINALS THROUGHOUT
THE DAY. PCPN REMAINS IN FORM OF VERY LIGHT FZRA N OF
KRIC/KSBY...AND WL NEED TO KEEP AN EYE ON TRENDS AS THE MORNING
PROGRESSES. HV ACCOUNTED FOR PERIODS OF RA/DZ ACROSS SITES THIS
MORNING...WITH DETERIORATING CONDS AS NEXT SLUG OF OVERRUNNING
MOISTURE ARRIVES FROM THE WEST.
S/SE WINDS VEER TOWARDS THE W/SW LATER THIS MORNING AS A WARM
FRONT LIFTS ACROSS THE AREA, BEFORE TURNING BACK TO THE NORTH LATE
THIS AFTN AS LOW PRESSURE TRACKS TO OUR WEST/NORTHWEST, PUSHING A
COLD FRONT THROUGH THE AREA TONIGHT.
OUTLOOK: ALTHOUGH PCPN IS EXPECTED TO END TONIGHT...WIDESPREAD
IFR IS FCST TO CONTINUE SUNDAY AND INTO MONDAY. A CHANCE FOR RAIN
RETURNS WITH THE NEXT COLD FRONT PASSAGE ON MONDAY WITH IMPROVING
CONDITIONS BEHIND THE FRONTAL PASSAGE FOR TUESDAY THROUGH MIDWEEK.
&&
.MARINE...
HV UPDATED SCA IN BAY TO BEGIN WITH 7AM ISSUANCE. WINDS TO
MARGINAL/LOW END SCA FOR A FEW HOURS THIS MORNING BEFORE
DIMINISHING BRIEFLY AS WINDS BECOME W/SW. WINDS RAMP BACK UPWARDS
BEHIND FRONTAL PASSAGE THIS AFTN.
PREV DISCUSSION...
LATEST WX ANALYSIS/OBSERVATIONS SHOWS WARM FRONT DRAPED JUST SOUTH
OF THE WATERS THIS MORNING...RESULTING IN E-SE WINDS AS OF 12Z.
WINDS WILL CONTINUE TO VEER TOWARDS THE S-SW THIS MORNING AS WARM
FRONT PUSHES NORTH (WHILE INCREASING IN SPEED (TO AVG 15-20 KT))
THROUGH MIDDAY. WARM FRONT WILL PUSH NORTH OF THE WATERS THIS
MORNING AND MEANDER JUST NORTH OF THE WATERS EARLY THIS AFTN...BEFORE
BEING SHUNTED BACK S ACROSS THE WATERS LATE THIS AFTN INTO
TONIGHT AS SFC LOW PRES MOVING ACROSS NC PUSHES OFFSHORE. RESULTANT
WIND DIRECTION WILL VEER AROUND TO THE N-NE BEHIND THE FRONTAL
PASSAGE. PRESSURE GRADIENT WILL TIGHTEN SIGNIFICANTLY AS SFC HIGH
PRESSURE CURRENTLY OVER THE UPPER MIDWEST SLIDES ACROSS NORTHEAST
US. THIS WILL RESULT IN WINDS RAMPING UPWARDS INTO SCA CRIT RANGE
(20 TO 25 KT)...WITH HIGHEST WINDS EXPECTED AFTER 00Z/7PM TONIGHT
THROUGH SUN MRNG. WINDS BEGIN TO DIMINISH AS GRADIENT SLACKENS SUN
AFTN...THOUGH RMN FM THE NE.
ONLY MINOR CHANGE TO SCA WAS TO RUN THROUGH SUN AFTN OVER THE BAY,
AND THROUGH LATE SUNDAY NIGHT OVER THE COASTAL WATERS.
WINDS BECOME LIGHT SUNDAY NIGHT INTO EARLY MONDAY AS HIGH PRESSURE
CONTINUES TO BUILD OVERHEAD, BUT RAMP UPWARDS GRADUALLY MONDAY AFTN
AHEAD OF THE NEXT FRONTAL SYSTEM WHICH APPROACHES FROM THE W MONDAY.
WINDS WL INITIALLY BE HIGHER OVER LAND MONDAY AFTN, BUT EVENTUALLY
EXPECT ANOTHER ROUND OF SCA CONDITIONS BY MONDAY NIGHT. CONDITIONS
IMPROVE BACK BELOW SCA CRITERIA ON TUE AS HIGH RPESSURE REBUILDS
INTO THE REGION FROM THE WEST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
VAZ048-049-062>064.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST SUNDAY FOR ANZ630>632-634.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 3 PM EST SUNDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EST
SUNDAY NIGHT FOR ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
SUNDAY NIGHT FOR ANZ656-658.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB
SHORT TERM...LKB
LONG TERM...DAP
AVIATION...MAM
MARINE...MAM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
602 AM EST SAT JAN 21 2012
.SYNOPSIS...
LOW PRESSURE CENTERED OVER THE TENNESSEE VALLEY WILL TRACK EAST
TODAY AND MOVE VERY SLOW THROUGH THE MID ATLANTIC REGION. THE
ASSOCIATED COLD FRONT WILL PUSH SOUTHEAST LATE THIS AFTERNOON AND
EVENING AS STRONG HIGH PRESSURE BUILDS SOUTH FROM NEW ENGLAND
OVERNIGHT INTO SUNDAY. A STRONGER COLD FRONT WILL AFFECT THE AREA
ON MONDAY...FOLLOWED BY HIGH PRESSURE BUILDING OVER THE SOUTHEAST
STATES TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FCST TO ADD WINTER WX ADSY FOR SOME OF THE NW
COUNTIES...AS AREA OF MODERATE PRECIPITATION IS OVERSPREADING THIS
AREA...AND SHOULD COINCIDE WITH TEMPS 32 F OR COLDER FOR ABOUT 3
HRS. USING LATEST RUC SFC- WET BULB TEMPERATURES SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT OBS...LOW LEVEL COLD AIR IS VERY SHALLOW...SUCH
THAT EVEN 1000-850 MB THICKNESSES ARE VERIFYING TOO WARM.
OTHERWISE...AREAS FARTHER TO THE SE OF THE ADVSY SHOULD ENCOUNTER
JUST RAIN FOR THE REST OF THE DAY...6 AM OBS SHOW DEW PT AT 34 F
AT RIC...SO THAT EVAPORATIVE COLUMN COOLING WILL NOT LOWER THE
TEMPS AS THEY DID LAST EVENING...SOME SPOTTY -FZRA MAY BE
POSSIBLE OVER EXTREME NW PORTIONS OF THE COUNTIES BORDERING THE
ADSY BUT ANY ACCUMULATION IS NOT LIKELY...AS SFC TEMPS SHOULD BE
ABOVE FREEZING SHORTLY.
LATER TODAY...RA/SHRA SHOULD COVER ALL AREAS BY LATE MORNING OR EARLY
AFTN. SOUTH OF THE BOUNDARY...ADDED ISO TSTMS FOR THE AFTN IN SE
VA/NE NC WHERE TEMPS RISE INTO THE UPR 50S TO MID 60S W/ DEW PTS
IN THE 50S. CURRENT AREA OF CONVECTION OVER KY/TN WILL LIKELY
BREAK APART WHEN IT INTERACTS W/ THE MTNS BUT MAY RE- GENERATE
THIS AFTN. ONLY MINIMAL INSTABILITY BUT THERE IS DECENT SHEAR SO
AN ISO STRONGER STORM IS POSSIBLE/MAIN THREAT BEING STRONG WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...MODELS AGREE THAT N/NE FLOW WILL OVERSPREAD THE ENTIRE
CWA BY 00Z...AS SFC LOW PUSHES OFF THE NC COAST. STILL LOTS OF LOW
LEVEL MOISTURE...BUT MID LEVEL DRYING FROM THE NORTH SHOULD BRING
AN END TO MOST OF THE PRECIP BETWEEN 00-03Z EXCEPT IN NE NC WHERE
IT LINGERS A FEW HRS LONGER. WV SATELLITE SUGGEST STRONG AREA OF
MID-UPPER CONFLUENCE OVER HUDSON BAY WILL SLIDE SE...ALLOWING WITH
A 1035 MB SFC HIGH TO BUILDING INTO ERN NY STATE/NEW ENGLAND. COLD
AIR FILTERS SOUTH ONCE AGAIN...BUT PRETTY GOOD CONSENSUS THAT
THIS WILL HOLD OFF UNTIL AFTER BULK OF PRECIP ENDS...I.E. PRECIP
ENDS BEFORE PTYPE CONCERNS BECOME A MAJOR ISSUE. FOR NOW WILL
MENTION POTENTIAL FOR FREEZING DRIZZLE ACRS NRN ZONES BEGINNING
AFTER ABOUT 03Z. LOWS IN THE UPR 20S NORTH...UPR 30S S.
SUN/SUN NIGHT...LOOKS TO BE A COLD DAY ON SUNDAY WITH NE FLOW. ONLY
CONCERN WOULD BE FOR FREEZING DRIZZLE IN THE MORNING OVER CENTRAL
VA...INCLUDING METRO RICHMOND AND AREAS ON NW AS LOW LEVELS REMAIN
BELOW CRITICAL THRESHOLDS FOR FROZEN PRECIP. VERY DRY ALOFT
HOWEVER...SO THIS WOULD BE NOTHING MORE THAN FREEZING DRIZZLE...WILL
MAKE AN HWO MENTION FOR NOW. SHOULD BE WARM ENOUGH FOR JUST -RADZ
BY AFTN (EXCEPT COULD BE CLOSE IN THE COLDER FAR NW ZONES. DOUBT
WE`LL SEE ANY BREAKS IN THE CLOUD COVER AS LOW LEVEL INVERSION
WILL BE DIFFICULT TO MIX OUT...PERHAPS A FEW PEEKS OF SUN IN THE
MORNING OVER THE FAR NORTH CLOSEST TO THE SFC HIGH. BREEZY
CONDITIONS ALONG THE COAST. FAVOR THE COLDER MET NUMBERS FOR
HIGHS...BASED ON LIMITED MIXING AND A LOW OVC...HIGHS RANGING FROM
THE UPPER 40S FAR SE VA/NE NC...MID- UPPER 30S NW ZONES. TEMPS
RISE OVERNIGHT SUNDAY NIGHT...AS SFC HIGH OVER NEW ENGLAND
RETREATS OFF TO THE NE...FOLLOWED BY SIGNIFICANT WARM-UP ON MON
AHEAD OF THE NEXT SYSTEM. FAVOR THE WARMER MAV VALUES ON MON W/
SSW FLOW BY LATE MORNING AFTN...HIGHS GENLY IN THE UPR 50S NW
(WHERE PRECIP COMES IN EARLIER) TO THE MID- UPR 60S SE. CHC TO
LIKELY POPS FOR SHOWERS ALL AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A SERIES OF WAVES WILL PASS NORTH OF THE FA DURING THE LONG TERM
PERIOD DRAGGING COLD FRONTS AND PERIODS PRECIP THROUGH THE AREA.
RAIN WILL BEGIN TO IMPACT THE AREA MONDAY AS AN UPPER LEVEL WAVE
PASSES OVER NORTHERN MICHIGAN. THE ASSOCIATED COLD FRONT CROSSES THE
AREA BRINGING A PERIOD OF RAIN AND A WIND SHIFT FROM THE S TO N. THE
MODELS VARY A BIT WITH THE STRENGTH OF THE SYSTEM...AND HAVE LEANED
TOWARD THE WEAKER ECMWF. BUT...IF THE GFS VERIFIES THERE COULD BE A
COUPLE TSTMS THAT DEVELOP IN NE NC AND SE VA. BENIGN WX PREVAILS AS
HIGH PRESSURE BUILDS OVER THE AREA TUESDAY NIGHT AND SLIDES OFF THE
COAST BY THURSDAY EVENING. THE NEXT SYSTEM LOOKS TO IMPACT THE AREA
FRIDAY MORNING AS A WARM FRONT BRINGS RAIN INTO THE AREA...FOLLOWED
BY A COLD FRONT THAT WILL BRING ANOTHER ROUND OF RAIN LATE FRI/EARLY
SAT. AGAIN THERE IS A BIT OF DISAGREEMENT WITH THE MODEL TIMING OF
THIS EVENT. THE ECMWF PROGRESSES THE UPPER LEVEL SYSTEM EAST MUCH
MORE QUICKLY THAN THE GFS. BEING THIS FAR OUT IN THE FORECAST...JUST
TRIED TO BLEND THE TIMING OF THE SCENARIOS TOGETHER.
EXPECT A BIT OF A ROLLER COASTER AS FAR AS TEMPS GO DURING THE
PERIOD. WITH THE APPROACH THE SYSTEM MONDAY...EXPECT HIGHS IN THE
MID 60S NORTH TO UPPER 60S SOUTH. AS THE FRONT CLEARS THE AREA
MILDER TEMPS WILL PREVAIL WITH HIGHS IN THE MID 50S TO 60 FOR TUES
AND WED. A WARMER DAY FOLLOWS ON THUR AS WINDS TURN SOUTH AHEAD OF
THE NEXT FRONT. LOWS WILL BE IN THE LOW 40S TUES...FALLING TO THE
LOW AND MID 30S FOR WED AND THUR...WARMING INTO THE MID 40S FOR FRI
AND SAT.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
ONGOING LIGHT TO MOD PCPN THIS MORNING IN ASSOCIATION WITH WEAK
ISENTROPIC LIFT. MVFR/TEMPO IFR CONDS ACROSS ALL BUT FAR SE
TERMINALS AS OF 06Z/1A...WITH CONDITIONS EXPECTED TO DETERIORATE TO
IFR BY 12Z/SAT AT NORTHERN TERMINALS AND CONTINUE THROUGHOUT THE
DAY. PCPN REMAINS IN FORM OF VERY LIGHT FZRA AT RIC AND HAS BEGUN AS
LGT SNOW AT SBY BUT CHANGE TO RAIN AT ALL TERMINALS IS EXPECTED BY
10Z.
NE/E WINDS FRIDAY EVENING VEER TO THE S/SW LATER THIS MORNING AS A
WARM FRONT LIFTS ACROSS THE AREA, BEFORE TURNING BACK TO THE NORTH
LATE SATURDAY AFTN AS LOW PRESSURE TRACKS TO OUR WEST/NORTHWEST,
PUSHING A COLD FRONT THROUGH THE AREA SAT AFTN/NIGHT.
OUTLOOK: ALTHOUGH PCPN IS EXPECTED TO END SAT NIGHT...WIDESPREAD IFR
IS FCST TO CONTINUE THROUGH SUNDAY AND PROBABLY MONDAY. A CHANCE FOR
RAIN RETURNS WITH THE NEXT COLD FRONT PASSAGE ON MONDAY WITH
IMPROVING CONDITIONS BEHIND THE FRONTAL PASSAGE FOR TUESDAY THROUGH
MIDWEEK.
&&
.MARINE...
LATEST WX ANALYSIS/OBSERVATIONS SHOWS WARM FRONT DRAPED JUST SOUTH
OF THE WATERS THIS MORNING...RESULTING IN E-SE WINDS AS OF 09Z.
WINDS WILL CONTINUE TO VEER TOWARDS THE S-SW THIS MORNING AS WARM
FRONT PUSHES NORTH (WHILE INCREASING IN SPEED (TO AVG 15-20 KT))
THROUGH MIDDAY. WARM FRONT WILL MEANDER JUST NORTH OF THE WATERS
LATE THIS MORNING INTO THE AFTN...BEFORE BEING SHUNTED BACK S ACROSS
THE WATERS THIS AFTN INTO TONIGHT AS SFC LO PRES MOVING ACROSS NC
PUSHES OFFSHORE. RESULTANT WIND DIRECTION WILL VEER AROUND TO THE
N-NE BEHIND THE FRONTAL PASSAGE. PRESSURE GRADIENT WILL TIGHTEN
SIGNIFICANTLY AS SFC HIGH PRESSURE CURRENTLY OVER THE UPPER MIDWEST
SLIDES ACROSS NORTHEAST US. THIS WILL RESULT IN WINDS RAMPING
UPWARDS INTO SCA CRIT RANGE (20 TO 25 KT)...WITH HIGHEST WINDS
EXPECTED AFTER 00Z/7PM TONIGHT THROUGH SUN MRNG. WINDS BEGIN TO
DIMINISH AS GRADIENT SLACKENS SUN AFTN...THOUGH RMN FM THE NE.
ONLY MINOR CHANGE TO SCA WAS TO RUN THROUGH SUN AFTN OVER THE BAY,
AND THROUGH LATE SUNDAY NIGHT OVER THE COASTAL WATERS.
WINDS BECOME LIGHT SUNDAY NIGHT INTO EARLY MONDAY AS HIGH PRESSURE
CONTINUES TO BUILD OVERHEAD, BUT RAMP UPWARDS GRADUALLY MONDAY AFTN
AHEAD OF THE NEXT FRONTAL SYSTEM WHICH APPROACHES FROM THE W MONDAY.
WINDS WL INITIALLY BE HIGHER OVER LAND MONDAY AFTN, BUT EVENTUALLY
EXPECT ANOTHER ROUND OF SCA CONDITIONS BY MONDAY NIGHT. CONDITIONS
IMPROVE BACK BELOW SCA CRITERIA ON TUE AS HIGH RPESSURE REBUILDS
INTO THE REGION FROM THE WEST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
VAZ048-049-062>064.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 3 PM EST SUNDAY
FOR ANZ634.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 3 PM EST SUNDAY FOR
ANZ630>633.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EST
SUNDAY NIGHT FOR ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
SUNDAY NIGHT FOR ANZ656-658.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB
SHORT TERM...LKB
LONG TERM...DAP
AVIATION...MAM
MARINE...MAM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
930 PM EST SUN JAN 22 2012
.UPDATE...
WV IMAGERY AND RUC ANALYSIS INDICATED A VIGOROUS SHRTWV MOVING INTO
WRN MO. TRENDS FROM THE 18Z MDLS AND 00Z NAM/RUC SUGGEST THAT THE
PROMINENT SHRTWV WILL SUPPORT A STRENGTHENING LOW A BIT FARTHER
SOUTH THAN PREVIOUS FCSTS. THE 00Z NAM HAS SHIFTED THE BULK OF THE
WAA/ISENTROPIC LIFT PCPN LATE TONIGHT INTO EARLY MON WELL TO THE
EAST COMPARED TO THE 18Z RUN WHILE THE 00Z RUC CONTINUES TO SUGGEST
THAT THE WAA SURGE WILL MOVE INTO CNTRL UPPER MI LATE TONIGHT BUT
WITH THE THERMAL GRADIENT ALSO SHIFTED A BIT TO THE EAST.
DIFFICULTIES HANDLING THE EXTENSIVE LINE OF CONVECTION MOVING INTO
ALSO LEADS TO GREATER UNCERTAINTY WITH THE MODELS SOLUTIONS.
SO...WITH CONFLICTING SIGNALS FROM MODEL OUTPUT...WILL NOT CHANGE
GOING HEADLINES AT THIS TIME. HOWEVER...HAVE TRIMMED ICE
ACCUMULATION AMOUNTS FOR LOCATIONS NEAR LAKE SUPERIOR AND LAKE
MICHIGAN WHERE TEMPS ARE EXPECTED TO CLIMB AOA FREEZING BY MORNING.
LARGER CHANGES MAY BE NEEDED WITH SNOW/ICE AMOUNTS LOCATION WHEN
ADDITIONAL INFORMATION IS AVAILABLE.
.SHORT TERM TO 00Z TUE...
UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE ROCKIES AND A
TROUGH OFF THE SE COAST. THERE IS ALSO A SHORTWAVE TROUGH OVER THE
NORTHERN PLAINS EMBEDDED IN THE ROCKIES TROUGH WITH A POTENT
SHORTWAVE OVER THE SOUTHERN ROCKIES. THIS POTENT SHORTWAVE EVEN HAS
SOME LIGHTNING WITH IT NEAR DENVER THIS MORNING. THE TWO SHORTWAVES
WILL AFFECT THE WEATHER AND BRING WINTRY PCPN WITH THEM.
NAM SHOWS THE SOUTHERN BRANCH SYSTEM FORMING A CLOSED 500 MB LOW AND
THIS LOW HEADS NORTHEAST AND COMBINES WITH THE NORTHERN BRANCH
SHORTWAVE IN THE NORTHERN PLAINS. NAM ALSO SHOWS SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE THROUGH MONDAY WITH
ISENTROPIC LIFT AND MOISTURE ON THE I280K-I295K SURFACES AS WELL.
GFS SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE THROUGH MONDAY AS
WELL. COMPARING MODELS...00Z ECMWF AT 18Z MONDAY IS THE FURTHEST NW
WITH THE UPPER LEVEL LOW WHILE THE GFS...NAM AND CANADIAN ARE MORE
TOWARDS NE WI FOR THE 500 MB LOW PLACEMENT.
TOUGH FORECAST FOR THIS PERIOD AS TO WHAT TYPES OF PCPN WILL
FALL...WHERE IT WILL FALL AND HOW MUCH. NAM CONTINUES TO SHOW THE
CUTOFF LINE FROM SNOW WEST OF A LINE FROM MARQUETTE TO IRON
MOUNTAIN. 12Z SOUNDINGS FROM KGRB AND KAPX SHOW DRY IN THE LOW TO
MID LEVELS AND THIS HAS PREVENTED PCPN FROM REACHING THE GROUND OVER
THE CWA TODAY. THE QUESTION IS HOW LONG THIS DRY AIR STICKS AROUND.
FOR ONE THING...THE DRY AIR SHOULD TAKE ANY ABOVE ZERO TEMPERATURES
ALOFT BACK BELOW ZERO WITH WET BULB COOLING AND KEEP THE PCPN AS
SNOW OR FREEZING DRIZZLE TODAY AND NOT SLEET.
NOT REAL CONFIDENT IN THIS FORECAST AS MODELS STILL HAVE A PROBLEM
WITH HOW MUCH WARM AIR IS COMING UP AND QPF TOTALS ARE DIFFERENT AS
WELL. WENT WITH A NAM ECMWF BLEND FOR THIS FORECAST WITH MORE
WEIGHTING ON THE MORE DETAILED NAM MODEL. NAM SHOWS THE 850 MB 0C
LINE STAYING AROUND THE IMT TO MQT AREA TONIGHT INTO EARLY MONDAY
AFTERNOON. TOP DOWN SOUNDING METHOD OF FORECASTING SHOWED PCPN
STAYING MOSTLY AS SNOW ACROSS THE FAR WESTERN CWA AND THEY COULD SEE
UP TO 7 INCHES OF SNOW ON MONDAY OUT BY ONTONAGON AND IRONWOOD AND
WENT WITH A WINTER STORM WARNING THERE FOR THE SNOW AMOUNTS. HEAVIER
PCPN DOES NOT ARRIVE UNTIL AFTER 06Z TONIGHT FOR THE CWA. THERE WILL
ALSO BE SOME FREEZING RAIN THAT COULD MIX IN WITH THE SNOW THERE AS
WELL. WENT WITH AN ICE STORM WARNING FOR MARQUETTE...DICKINSON AND
MENOMINEE COUNTIES AS THE 850 MB 0C LINE IS RIGHT ACROSS THIS AREA.
LOOKED LIKE PCPN WOULD BE A BIT OF SNOW...BUT MOSTLY FREEZING RAIN
FOR TONIGHT AND ALSO FOR MONDAY MORNING. TO THE EAST...FREEZING RAIN
IS A BIT LESS FOR AMOUNTS AND WENT WITH A FREEZING RAIN ADVISORY AS
TEMPERATURES WILL BE WARMER THERE AND WILL GET ABOVE FREEZING ON
MONDAY. TO THE WEST BETWEEN THE WARNINGS...WENT WITH A WINTER
WEATHER ADVISORY FOR MIXED PCPN. NOT ENOUGH SNOW ACCUMULATIONS OR
FREEZING RAIN FOR WARNINGS...SO WINTER WEATHER ADVISORY LOOKED GOOD.
HAD ALL THE HEADLINES START AT 06Z TONIGHT. COLD AIR COMES IN ON
MONDAY AFTERNOON AND SWITCHES THE PCPN OVER TO ALL SNOW MONDAY
AFTERNOON. DID NOT CHANGE MUCH FOR TEMPERATURES AS THEY DID NOT
REALLY WARM UP TODAY. ENDED UP LOWERING HIGH TEMPERATURES A BIT
TODAY AND HAVE THE LOW TEMPERATURES TONIGHT EARLY IN THE EVENING
WITH SLOWLY RISING TEMPERATURES TONIGHT INTO MONDAY MORNING WITH A
NON-DIURNAL CURVE. QPF FROM THIS EVENT LOOKS TO BE 0.40 TO 0.67 INCH
WITH FREEZING RAIN THE MAIN PCPN TYPE OVER THE CENTRAL CWA AND SNOW
IN THE WEST. IF THE WARMER AIR MOVES A BIT FURTHER WEST...THE
HEADLINES AND FREEZING RAIN AMOUNTS WILL NEED TO BE ADJUSTED
FURTHER. ICE STORM WARNINGS AND FREEZING RAIN ADVISORIES WERE ALSO
ISSUED BECAUSE PAVEMENT TEMPERATURES WILL STILL BE BELOW FREEZING
FOR A WHILE AND EVEN IF AIR TEMPERATURES GET ABOVE FREEZING...IT
WILL FREEZE ON THE PAVEMENTS WITH BELOW FREEZING TEMPERATURES ON THE
ROAD SURFACES WHICH WOULD JUSTIFY THE ICE STORM WARNING AND FREEZING
RAIN ADVISORIES.
.LONG TERM /MONDAY NIGHT THROUGH NEXT SUNDAY/...
MONDAY NIGHT AND TUESDAY...MESSY PRECIPITATION PRODUCING SYSTEM WILL
BE ON ITS WAY OUT OF THE CWA MONDAY EVENING. HIGH POPS ALL AREAS IN
THE EVENING AS DEFORMATION PRECIP COLLAPSES FM WEST TO EAST ACROSS
CWA. SOUNDINGS INDICATE FAR EAST CWA MAY STILL BE CONTENDING WITH
RAIN EARLY IN THE EVENING...BUT SWITCHED OVR TO SNOW ALL AREAS BY
LATE EVENING. ADDITIONAL SNOW AMOUNTS AFT 00Z TUESDAY ARE KIND OF
QUESTIONABLE. DEEP MOISTURE TO H7 REMAINS ENTRENCHED OVR THE AREA
BUT LARGER SCALE UVM IS LACKING. ONSHORE WINDS MAY ENHANCE SNOW OVR
FAR WEST AND WITH H85 TEMPS DROPPING BLO -10C THERE COULD ALSO BE
LAKE ENHANCEMENT. LAKE SNOW PARAMETER IS PRETTY MUCH MAX OUT OVR
MUCH OF THE WESTERN CWA...BUT THIS IS LIKELY DUE TO ALL THE MID
LEVEL MOISTURE STILL PRESENT. BEST CHANCE FOR DECENT SNOW AMOUNTS
WILL BE IN THE FAR WEST DUE TO TERRAIN AIDED LIFTING. BLSN/DRSN WILL
BECOME ISSUE ALONG SHORELINE OF LK SUPERIOR IN THE WEST THIRD OF CWA
MUCH OF THE NIGHT DUE TO DEVELOPING GUSTY NW WINDS OVR 30 MPH. KEPT
HIGHER POPS FOR LK EFFECT OVR NW FLOW AREAS EAST OF MARQUETTE ON
TUESDAY. DEEP MOISTURE DEPARTING AND LOWERING INVERSIONS/MARGINAL
INSTABILITY SHOULD KEEP SNOW ACCUMS LIMITED ON TUESDAY. THOUGH
COOLER THAN MONDAY IN MOST AREAS...MAX TEMPS ON TUESDAY WILL STILL
BE A BIT ABOVE NORMAL.
LK EFFECT GRADUALLY DIMINISHES/ENDS TUESDAY NIGHT OVR EASTERN CWA
WITH WARMING TEMPS AT H9 AND BACKING LOW-LEVEL WINDS. WEAK SFC
RIDGE POKES INTO WESTERN INTERIOR OVERNIGHT ALONG WITH PWAT MIN.
FAVORED LOWER END OF GUIDANCE FOR TEMPS WHICH RESULTED IN MINS ZERO
TO 5 ABOVE IN THE INTERIOR SW. MAY SEE SOME MID CLOUDS STREAMING IN
AHEAD OF NEXT SYSTEM BUT OTHERWISE WEDNESDAY SHOULD BE QUIET. TEMPS
IN SOME AREAS WILL REACH ABOVE FREEZING...THIS TIME WITHOUT THE
MESSY MIX OF RAIN AND SNOW.
IN THE EXTENDED...MEDIUM RANGE MODELS IN PRETTY GOOD AGREEMENT WITH
UPPER AIR/SFC PATTERN INTO NEXT WEEKEND. GIVEN FCST OF FAIRLY FAST
WEST TO EAST PACIFIC FLOW...THE AGREEMENT IN THE MODELS LENDS HIGHER
CONFIDENCE TO THE FORECAST. MAIN SYSTEMS TO AFFECT THE UPR LAKES
REGION ARE WEDNESDAY NIGHT INTO THURSDAY THEN AGAIN FRIDAY AND
FRIDAY NIGHT. BOTH SYSTEMS ARE LACKING MOISTURE AS HIGHER PWATS
REMAIN OVR CNTRL AND SOUTHERN STATES CLOSER TO MORE ACTIVE JET
STREAM. ONLY REAL CHANCE OF SNOW WILL BE LATER WEDNESDAY NIGHT INTO
THURSDAY OVER LK SUPERIOR AND PERHAPS INTO THE EASTERN CWA. COLD AIR
IS LACKING OVR THE UPR LAKES WITH TEMPS THURSDAY AND FRIDAY FCST TO
BE ABOVE NORMAL FOR DAYTIME HIGHS AND NIGHTTIME LOWS. LACK OF COLD
AIR LEADS TO MINIMAL LK EFFECT CONCERNS AS WELL. PUT SOME POPS FOR
NW FLOW LK EFFECT IN FOR NEXT WEEKEND THOUGH AS MODELS SHOW H85
TEMPS BLO -10C IN WAKE OF TROUGH PASSING THROUGH ON FRIDAY. IN A
NUTSHELL...NO REAL SIGNIFICANT WEATHER CONCERNS ARE EXPECTED FOR THE
NEXT WEEK BEYOND THE EVENT ENDING MONDAY NIGHT.
&&
.AVIATION /FOR THE 00Z TAF ISSUANCE/...
FLOW AROUND LOWER PRESSURE TO THE SOUTHWEST OF THE AREA HAS ALLOWED
LOW LEVEL MOISTURE TO RETURN KEEPING CEILINGS IN THE IFR RANGE AT
IWD AND CMX...WHILE SAW HAS FALLEN INTO THE LIFR CATEGORY DUE TO
UPSLOPE FLOW OUT OF THE SOUTH. SOUNDINGS INDICATE THAT SNOW WILL BE
THE MAIN WX CATEGORY FOR IWD AND CMX...WHILE SAW WILL SEE -FZRNSN AS
SOUNDINGS ARE NEARLY ISOTHERMAL ALONG THE 0 DEGREE ISOTHERM. ENOUGH
COLD AIR SHOULD FILTER IN BEHIND THE LOW MONDAY AFTERNOON TO CHANGE
PRECIP OVER TO SNOW AT SAW. CEILINGS SHOULD BEGIN TO IMPROVE
SLIGHTLY AS FLOW BECOMES NORTHWESTERLY DURING THE SAME TIME PERIOD
AT SAW.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
GALES WILL BE WINDING DOWN LATE THIS AFTERNOON OVER THE EAST HALF OF
LAKE SUPERIOR. THE PRESSURE GRADIENT WILL RELAX SOME TONIGHT INTO
MON MORNING AS THE PLAINS LOW MOVES NE TOWARD THE UPPER LAKES. AS
THE LOW MOVES ACROSS EASTERN LAKE SUPERIOR MON AFTN AND THEN INTO
ONTARIO MON NIGHT...IT APPEARS NORTHWESTERLY GALES WILL DEVELOP IN
ITS WAKE ACROSS CNTRL AND EASTERN PORTIONS OF THE LAKE. WINDS WILL
DIMINISH W TO E TUE AFTN/NIGHT WITH THE APPROACH OF A HIGH PRES
RIDGE. ALTHOUGH ANOTHER LOW PRES MAY IMPACT THE LAKE THU...NO
ADDITIONAL GALES APPEAR LIKELY ATTM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST
/6 PM CST/ MONDAY FOR MIZ001-003-004-010-084.
WINTER STORM WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST /6
PM CST/ MONDAY FOR MIZ002-009.
FREEZING RAIN ADVISORY FROM 1 AM TO 1 PM EST MONDAY FOR MIZ006-
013.
ICE STORM WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 1 PM EST /NOON
CST/ MONDAY FOR MIZ005-011-012.
FREEZING RAIN ADVISORY FROM 1 AM TO 10 AM EST MONDAY FOR MIZ007-
014-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ249>251-264-266-
267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...07
LONG TERM...JLA
AVIATION...KEC
MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
352 PM EST SAT JAN 21 2012
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LKS BTWN ARCTIC VORTEX CEMTERED OVER HUDSON BAY ASSOCIATED
WITH RECENT INTENSE CHILL AND PROGRESSIVE UPR RDG SHIFTING E THRU
THE NRN PLAINS. SFC/H85 RDG AXIS HAS BROUGHT RELATIVELY TRANQUIL WX
TO THE FA TDAY WITH MID LVL DRY AIR SHOWN ON THE 12Z GRB RAOB. TEMPS
HAVE RISEN STEADILY FM MRNG LOWS ARND -25F OVER THE INTERIOR W. SOME
LES LINGERS EARLY THIS AFTN OVER THE KEWEENAW AND IN AREAS WELL E OF
MQT WITH H85 TEMPS STILL AOB -15C...BUT BACKING LLVL FLOW TO THE SW
THAT SIGNALS A RETREAT OF THE ARCTIC AIR IS CAUSING THE SHSN TO
DRIFT TO THE NE. IN FACT...WAD MID CLD BEST DEPICTED BY THE RH SHOWN
ON THE 12Z NAM 290-295K ISENTROPIC SFCS/H6-7/ AND WELL IN ADVANCE OF
SHARP H85 WARM FNT PUSHING THRU THE NRN PLAINS IS ALREADY MOVING FM
NRN MN INTO THE WRN CWA. BUT GENERALY DRYNESS OF THE 12Z INL RAOB IS
PREVENTING ANY PCPN. SOME -SN IS SHOWING UP NEAR LK WINNIPEG. TO THE
S...THERE IS QUITE A BIT OF LO CLD S OF THE HI CENTER IN WI...AND
THIS ST/SC IS STARTING TO STREAM NWD INTO SW MN. FARTHER W...12Z H85
TEMPS WERE UP TO 6C IN THE LEE OF THE ROCKIES BEHIND THE WARM FNT. A
VIGOROUS SHRTWV IS DIGGING SEWD INTO THE SW STATES. THERE HAVE BEEN
A FEW LTG STRIKES NEAR THE TRACK OF THIS FEATURE...AND NEARBY PIREPS
INDICATE H3 WIND SPEEDS UP TO 175KT WITHIN SUPPORTING UPR JET THAT
IS WELL DEFINED ON WV IMAGERY.
&&
.SHORT TERM DISCUSSION /TNGT AND SUN/...
MAIN FCST CONCERNS IN THIS PERIOD ARE IMPACT OF RETURNING WARM AIR
IN VIGOROUS WAD PATTERN THAT WL SET UP IN RETURN SLY FLOW BTWN
DEPARTING HI PRES RDG TO THE E AND DVLPG LO PRES IN THE PLAINS
ASSOCIATED WITH VIGOROUS HGT FALLS IN ADVANCE OF SHRTWV NOW MOVING
INTO THE SW STATES.
TNGT...WITH STRENGTHENING LLVL SLY FLOW...EXPECT ANY LES NEAR LK SUP
TO DRIFT OFFSHORE BY LATE IN THE AFTN. SINCE THE AIRMASS WL STILL BE
COLD ENUF FOR LES EARLY WITH H85 TEMPS ARND -12C...GOING FCST OF
SOME LK CLD/SHSN OFF LK MI INTO THE FM ISQ-ERY STILL LOOKS ON TRACK.
BUT THIS PCPN SHOULD DIMINISH AS TEMPS RISE THRU THE NGT. IN FACT...
H85 WIND INCRSG UP TO 50KTS TOWARD WRN LK SUP BY 12Z SUN ARE FCST TO
PUSH H85 TEMPS NEAR 0C IN THAT AREA TOWARD DAYBREAK. THIS
STRENGTHENING SSW FLOW WL ALSO DRAW THE LO CLD NOW WELL TO THE S
INTO THE WRN AND CNTRL CWA. BUT DOWNSLOPE NATURE OF THE FLOW OVER
THE W AND NCNTRL SHOULD RESULT IN SOME DISSIPATION OF THIS CLD
COVER. TO THE NW...THE AREA OF SN NOW NEAR LK WINNIPEG WL LIKELY
SHIFT NEAR ISLE ROYALE WITH PERSISTENT ISENTROPIC ASCENT SHOWN ON
THE 290-295K SFCS...MORE SATURATED PROFILE DOWN TO THE SFC...AND
INCRSG UPR DVGC IN RRQ OF H3 JET MAX IN ONTARIO AND IN EXIT REGION
OF ANOTHER UPR JET EMERGING ON THE E SIDE OF DEEPENING UPR TROF IN
THE PLAINS. WITH 5-6K FT DEEP DRY WEDGE SHOWN ON FCST SDNGS FOR
CMX...SUSPECT THE BULK OF THIS PCPN WL REMAIN TO THE NW OF THE
KEWEENAW. SO CUT POPS INTO THE CHC CATEGORY FOR THAT AREA WITH HIER
POPS TO THE N. EXPECT THE LOWEST TEMPS EARLY TNGT...WITH THE MERCURY
RISING LATER AS INCRSG S WIND ADVECTS MORE LLVL MSTR INTO THE AREA.
TENDED TO LOWER EARLY EVNG TEMPS OVER THE INTERIOR CNTRL BEFORE
ARRIVAL OF THICKER CLD COVER/ONSET OF STRONGER WINDS CAUSES TEMPS TO
RISE OVERNGT.
SUN...THE WX WL BE DOMINATED BY THE ARRIVAL OF INCRSG LLVL MSTR IN
STEADY SSE WIND BTWN DEPARTING HI PRES RDG AND DVLPG LO IN THE
PLAINS. ALTHOUGH CONTINUED WAD WL TEND TO RESULT IN INCRSG MID LVL
MSTR AS WELL...MODEL GUIDANCE INDICATES A PERSISTENT DRY WEDGE
CENTERED ARND H85 THRU THE DAY BTWN THE LLVL AND HIER LVL
MOISTENING. MAINTAINED MAINLY SCHC POPS FOR LARGER SCALE PCPN...HIER
TO THE NW. ANY PCPN WL LIKELY BE SN AND PSBLY SLEET WITH WARM
WEDGE/H85 TEMPS POTENTIALLY UP TO 5C IN THE DRY LYR THAT MIGHT MELT
SN FLAKES ABV RESIDUAL COLD AIR JUST ABV THE SFC...WHERE TEMPS ARE
FCST TO REMAIN AS LO AS -6C TO -8C. ALSO INCLUDED MENTION OF FZDZ
MAINLY OVER THE SCNTRL WHERE GUIDANCE SHOWS INCRSG SFC DEWPTS IN
AREA OF UPLSOPE SSE FLOW. LIMITING FACTOR WL BE FAIRLY HI SFC DEWPT
DEPRESSIONS NOW OBSVD TO THE S/STRONG WINDS THAT MIGHT MAINTAIN A
SLIGHT INVERTED V LLVL THERMAL/MSTR PROFILE.
.LONG TERM /SUNDAY NIGHT THROUGH NEXT SATURDAY/...
DEEPENING LOW PRESSURE OVER THE UPPER LAKES AND MIXED PRECIPITATION
ISSUES IS THE MAIN CONCERN OF THE LONG TERM.
BY SUNDAY EVENING...SHORTWAVE TROUGH WITH AT LEAST TWO EMBEDDED
SHORTWAVES/PV ANOMALIES WILL BE OVER THE CNTRL PLAINS. MAJORITY OF
MODELS AGREE IN THIS IDEA. 12Z NAM IS ON ITS OWN SHOWING STRONGER
PIECE OF ENERGY SHOOTING NORTH INTO MN. ALL OTHER GUIDANCE...SAVE THE
SREF WHICH HAS MANY NAM MEMBERS WITHIN IT...KEEPS STRONGEST ENERGY
MORE OVR SOUTHERN PLAINS. BASED ON POSITION OF UPPER JET AHEAD OF
TROUGH...THINK NAM IS TOO STRONG WITH SHORTWAVE OVR MN. THIS LEADS
TO A MUCH FARTHER NORTH TRACK TO SFC LOW ON MONDAY (NORTHERN LK
SUPERIOR MONDAY MORNING INSTEAD OF OVR SOUTHERN LK MICHIGAN). SO AS
MUCH AS WOULD HAVE LIKED TO HAVE THE HIGHER RESOLUTION NAM THERMAL
PROFILES TO USE IN THIS FCST...HAVE TO DISCOUNT THE NAM AT THIS
TIME. SHOULD NOTE THAT IT APPEARS THE 12Z NAM IS TRENDING TOWARD
MAJORITY OF OTHER MODELS...SO MAYBE IT WILL BE MORE USEFUL IN 24
HRS. MOVING ON THAT LEAVES THE ECMWF AND UKMET IDEA (WHICH HAVE BEEN
CONSISTENT AND PREFERRED WITH THIS SYSTEM FOR SOME TIME NOW) AS WELL
AS THE GFS WHICH BEGAN TRENDING TOWARD ECMWF/UKMET IDEA WITH THE 18Z
RUN ON 1/20. CANADIAN ALSO PRETTY MUCH IN LINE NOW AS WELL...THOUGH
RUN-TO-RUN CONSISTENCY WITH SFC LOW TRACK ON MONDAY STILL NOT THE
GREATEST. SHOULD NOTE...12Z GFS DID TREND A BIT TOWARD NAM IDEA AND
WAS NOT PREFERRED BY HPC. 12Z ECMWF/CANADIAN/UKMET REMAIN CONSISTENT
WITH PREVIOUS MODEL RUNS.
APPEARS THAT THOUGH THERE IS SOME INTERACTION WITH NORTHERN STREAM
LATER MONDAY AND MONDAY NIGHT...THIS SYSTEM WILL BE MAINLY SOUTHERN
STREAM ORIGIN. WITH THAT WILL COME GOOD TAP OF GULF MOISTURE WITH
PWATS OVR 250 PCT OF NORMAL BY 12Z MONDAY OVR MOST OF THE CWA.
POSITION OF H85 TROUGH AND SRLY H85 WINDS PUT STRONGEST H85 THETA-E
ADVECTION OVER EAST HALF OF CWA BTWN 09Z-15Z MONDAY. HEAVIEST QPF IS
FCST OVR CNTRL AND EAST CWA. RUN TOTAL QPF THROUGH 00Z TUESDAY (WHEN
DEEPER MOISTURE/HIGHER PWATS SHIFT TO THE NORTHEAST INTO
ONTARIO/QUEBEC) RANGE FROM 0.50-0.90 OF AN INCH WITH CANADIAN UP OVR
1 INCH...HEAVIEST CNTRL CWA DUE TO DEFORMATION ON BACK EDGE OF
H85-H7 LOWS AND IT IS ALSO WHERE THERE IS A HINT OF A TROWAL HANGING
BACK OVR THE AREA AS H85-H7 LOWS MAINTAIN STEADY STRENGTH WHILE
HEADING INTO ONTARIO.
LOW-LEVEL THERMAL PROFILES WILL BE CRITICAL COMPONENT WITH THIS
SYSTEM...ESPECIALLY THROUGH NOON ON MONDAY. BASED ON 0C H85
LINE...RAIN WILL BE MAIN PTYPE EAST OF MARQUETTE AND DICKINSON
COUNTIES...WITH SNOW TO THE WEST. TROUBLE IS THAT SFC-BLYR TEMPS
WILL BE VERY CLOSE TO FREEZING AS THE RAIN ARRIVES FM THE SOUTH LATE
SUNDAY NIGHT. COULD EVEN BE SLEET OR SNOW RIGHT AT THE ONSET OF
PRECIPITATION SUNDAY NIGHT AS WELL AS COLD AIR ALOFT SLOWLY EVADES.
BELIEVE FREEZING RAIN WILL BE BIGGEST CONCERN TOWARD DAYBREAK MONDAY
AND THROUGH ABOUT MID MORNING...THEN BLYR WARMING IN THE EAST SHOULD
CHANGE PTYPE TO JUST RAIN. DUE TO COLD SPELL LATELY...WARMING OF
GROUND SFC TEMPS WILL LAG THE AIR TEMPS...SO MAY BE SITUATION WHERE
TEMPS AT OBSERVATION PLATFORMS (ASOS/AWOS/RAWS) ARE IN THE MID 30S
BUT THERE IS STILL ICING OCCURRING ON COLDER UNTREATED SURFACES.
UNFORTUNATELY...THESE THERMAL QUESTIONS ABOUND THE FIRST PART OF
MONDAY WHEN BULK OF HEAVIER QPF IS FCST WITH WARM AIR ADVECTION
ALOFT AT ITS PEAK. DO THINK THERE IS A GREATER THAN 50 PCT CHANCE
OF SIGNIFICANT ICING LATE SUNDAY NIGHT AND MONDAY MORNING...
ESPECIALLY AWAY FM THE IMMEDIATE SHORELINES OF LK SUPERIOR AND LK
MICHIGAN.
EVENTUALLY...BLYR WARMING WILL RESULT IN MOSTLY RAIN BY LATE MORNING
EAST OF MUNISING TO MENOMINEE AS SFC LOW IS FCST TO DEEPEN AND MOVE
FM SOUTHEAST WI TO SCNTRL UPR MI AND EVENTUALLY OUT OVR SOUTHEAST LK
SUPERIOR BY MONDAY EVENING. SITUATION COULD BECOME VERY FAVORABLE
FOR HEAVIER SNOW OVR CNTRL CWA THOUGH...MAINLY OVR HIGHER TERRAIN
JUST WEST OF MARQUETTE INTO PORTIONS OF KEWEENAW AND AS FAR SOUTH
AS WI BORDER...EVENTUALLY SPREADING INTO ALGER AND DELTA COUNTIES BY
LATE AFTN. PRIMARYDRIVER FOR POTENTIALLY HEAVIER SNOW IS VERY TIGHT
H85 TEMPERATURE GRADIENT OVR CNTRL CWA/INCREASING DEFORMATION ON
WEST SIDE OF CLOSED OFF H85-H7 LOWS AND LINGERING TROWAL REGION MOST
NOTED 950-750MB. NORTHERN STREAM WAVE DIGGING INTO THE SOUTHERN STREAM
SYSTEM WILL ALSO LEAD TO STRONGER DEFORMATION PRECIP REGION.
HEADLINES...GIVEN THIS SYSTEM WILL BE AFFECTING THE AREA ON A MONDAY
WHEN THERE IS LOT OF TRAVEL WITH WORK/SCHOOL/ETC AND SINCE THIS
SYSTEM HAS POTENTIAL TO BE HIGHER IMPACT DUE TO AMOUNT OF MOISTURE
AVAILABLE...THINK GOING WITH A WATCH RIGHT NOW IS A GOOD IDEA. MAIN
ISSUE FOR ALGER AND DELTA COUNTY EASTWARD IS THE INITIAL ICE THREAT
LATER SUNDAY NIGHT INTO MONDAY MORNING. A MIXED BAG OF ICE AND SNOW
AND SOME SLEET IS MAIN ISSUE FOR AREAS OVR CNTRL UPR MI...BASICALLY
MARQUETTE AND DICKINSON/MENOMINEE COUNTIES. FARTHER WEST...IT WOULD
BE GENERALLY A SNOW EVENT. ONLY PLACE WHERE WINTER STORM WATCH WILL
NOT BE ISSUED IS FAR WEST CWA AS MODELS ARE VERY INSISTENT IN SHOWING
THEM BEING MISSED BY INITIAL WARM AIR ADVECTION PRECIPITATION LATE
SUNDAY NIGHT/MONDAY MORNING AND GENERALLY KEEPING THE PRIMARY
DEFORMATION AXIS TO THE EAST OF THOSE AREAS ON MONDAY AFTN/MONDAY
EVENING. WATCHES WILL RUN FM LATE SUNDAY NIGHT THROUGH MONDAY
EVENING FOR MARQUETTE AND DICKINSON COUNTIES WESTWARD BUT WILL KEEP
ENDING TIME SHORTER FARTHER EAST AS MOST PTYPE BY AFTN WILL BE
RAIN/DRIZZLE AND SNOW SHOULD NOT BE SIGNIFICANT...ESPECIALLY IN FAR
EAST TOWARD KERY.
LK EFFECT...POSSIBLY ENHANCED BY DEPARTING SYSTEM WILL TARGET NW
FLOW AREAS LATER MONDAY NIGHT INTO TUESDAY MORNING. GUSTY NW WINDS
WILL LEAD TO BLSN ISSUES AS WELL. WILL GO AHEAD AND RUN WATCHES
THROUGH 12Z WHERE LK EFFECT/BLSN WILL BE HAZARD LATER MONDAY NIGHT.
COORD WITH DLH...GRB...APX AND ALSO HPC ON THIS SYSTEM.
FOR THE EXTENDED /TUESDAY NIGHT THROUGH SATURDAY/...
A SLIGHTLY AMPLIFIED FLOW WITH A BROAD EASTERLY TROUGH AND WEAK
WESTERN RIDGE WILL DEVELOP AND LEAD TO A GENERALLY SUSTAINED WNW/NW
FLOW OVER THE UPPER GREAT LAKES THROUGH MOST OF THE PERIOD. A SERIES
OF SHORTWAVE TROUGHS AND RIDGES WILL PROGRESS ALONG THE WESTERN SIDE
OF THE EASTERN TROUGH AND ALLOW FOR PERSISTENT BUT SMALL PRECIP
CHANCES. HOWEVER...THERE IS DISAGREEMENT IN THE GUIDANCE WITH THE
TIMING OF EACH OF THESE PULSES.
CAA ON THE BACKSIDE OF MONDAYS DEPARTING LOW WILL CEASE TUESDAY
EVENING AS SFC/850MB WINDS BACK TO THE WEST WITH THE PASSAGE OF A
SHARP MID LEVEL RIDGE. SOME LES WILL REMAIN EARLY IN THE EVENING
ACROSS EASTERN PARTS OF THE CWA...AND THROUGHOUT THE EVENING IN THE
KEWEENAW PENINSULA. THERE WILL BE A BRIEF BREAK AFTER THE RIDGE
PASSES BEFORE THE FIRST IMPULSE DIGS SOUTHEAST OUT OF SOUTH CENTRAL
CANADA WEDNESDAY NIGHT THROUGH THURSDAY. THE GFS AND ECMWF WERE IN
DECENT AGREEMENT WITH THE STRENGTH OF THIS WAVE...BUT THE 12Z GFS
HAS TRENDED STRONGER. AT THE SAME TIME...THE GEM HAS NEARLY ZONAL
FLOW WEDNESDAY BEFORE DEVELOPING A WEAK SHORTWAVE THURSDAY
AFTERNOON. ALL THREE MODELS DO KEEPS MUCH OF THE PRECIPITATION OVER
LAKE SUPERIOR AND THE EASTERN HALF OF THE CWA...SO WILL KEEP CHANCES
IN THE FORECAST FOR WEDNESDAY NIGHT. ONLY A VERY SHORT PERIOD OF
LES...6 TO 12 HOURS...IS POSSIBLE FOR WNW FAVORED WIND BELTS
THURSDAY AS BOTH THE GFS AND ECMWF ARE VERY AGGRESSIVE IN BRINGING
DRY AIR AND A SHARP LOW LEVEL RIDGE ACROSS LAKE SUPERIOR THURSDAY
EVENING. EVEN MORE...RAPIDLY LOWERING INVERSION HEIGHTS TO BELOW
3KFT AND TEMPERATURES BELOW THE INVERSION GENERALLY >-12C WILL LOWER
GOOD LES CHANCES.
MORE DISAGREEMENT RESIDES WITH THE NEXT WAVE PROGGED TO PASS TO THE
NORTH OF THE CWA ON FRIDAY. THE 00Z ECMWF SHOWS AN OPEN WAVE AT
500MB OVER WESTERN ONTARIO 18Z FRIDAY...WHEREAS THE GFS HAS A CLOSED
500MB LOW OVER NORTHERN MANITOBA. THE GFS HAS BEEN RATHER CONSISTENT
WITH THIS FEATURE FOR THE LAST DAY WHILE THE ECMWF PULLED THE TROUGH
FURTHER SOUTH. ATTM...THE GFS SEEMS TO BE THE BETTER CHOICE...THOUGH
BOTH HAVE A COLD FRONT MOVING ACROSS CWA DURING THE DAY FRIDAY. AS
THIS OCCURS...THE SURFACE LOW WILL BE TRACKING JUST AHEAD OF THE
MIDLEVEL LOW ALONG THE SOUTHWEST SHORE OF HUDSON BAY. NEAR THE CWA
THE FORCING WILL BE PURELY FRONTAL...WITH THE STRONGEST BAND OF
FRONTOGENESIS NORTH OF LAKE SUPERIOR BETWEEN 500 AND 700MB.
THERE IS ALSO CONCERN ABOUT THE LACK OF MOISTURE WITH THIS FRONTAL
PASSAGE AS AIR AHEAD OF THE FRONT WILL BE PULLED FROM DRY
CONTINENTAL AIR IN THE LEE OF THE NORTHERN ROCKIES.
AIR BEHIND THE COLD FRONT ON FRIDAY WILL BE OF WARMER PACIFIC
ORIGIN...WITH INVERSION HEIGHTS DROPPING INTO THE EVENING. NW FLOW
LES WILL STILL BE A POSSIBILITY...BUT WILL BE GREATLY SUPPRESSED BY
LOW INVERSIONS AND HIGH 850/925MB TEMPERATURES. AIR OF MORE ARCTIC
ORIGIN COMES IN BEHIND A SECONDARY COLD FRONT ON SATURDAY
MORNING...THOUGH MOISTURE IS LACKING WITH THIS FRONT AS WELL. WILL
STAY GENERALLY DRY IN TERMS ON POTENTIAL FRONTAL AND LES PRECIP
EXCEPT ALONG THE KEWEENAW PENINSULA.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
ALTHOUGH SOME LO CLDS/MVFR CIGS MAY LINGER AT CMX EARLY IN THIS TAF
PERIOD...EXPECT THIS LO CLD TO LIFT AWAY TO THE N SOON AFTER TAF
ISSUANCE WITH STRENGTHENING S WIND. OTRW...VFR CONDITIONS WILL
PREVAIL INTO TNGT. THEN STEADY S WIND WILL ADVECT ABUNDANT LLVL
MSTR/LO CLD NOW SHOWING UP WELL TO THE S INTO UPR MI LATE TNGT THRU
SUN MRNG. EXPECT DOWNSLOPING WIND COMPONENT AT IWD/CMX TO BREAK UP
THE BULK OF THIS CLD IN THOSE LOCATIONS...WITH BETTER CHC OF MVFR
CIG IMPACTING THE SAW LOCATION WITH MORE OF AN UPSLOPE WIND
COMPONENT THERE.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
OPTED TO UPGRADE GALE WATCH TO A WARNING OVER THE E PART OF LK SUP
FOR LATE TONIGHT THRU SUN WITH STRENGTHENING SLY FLOW UNDER
SHARPENING PRES GRADIENT BETWEEN DEPARTING HI PRES RIDGE TO THE E
AND DEVELOPING LO IN THE PLAINS. A NNW GALE IS LOOKING MORE LIKELY
FOR MON NIGHT/TUE AS DEEPENING LO PRES TRACKING JUST TO THE E MOVES
INTO SE CANADA. THE WINDS WILL DIMINISH BY TUE NIGHT WITH APPROACH
OF HI PRES RIDGE. ALTHOUGH ANOTHER LO PRES MAY IMPACT THE LAKE ON
THU...NO GALES APPEAR LIKELY ATTM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT
FOR MIZ001-003-004.
WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH LATE MONDAY
NIGHT FOR MIZ005-006-011>014-085.
WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY
AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 7 PM EST SUNDAY FOR LSZ266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
EXTENDED...TK
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
704 PM CST Sun Jan 22 2012
.UPDATE...
/651 PM CST Sun Jan 22 2012/
A localized area of strong low-level convergence is developing close
to the surface low which is tracking across the southern KC metro at
this time. Increasing winds around 2000 ft AGL are bringing in a
surge of low-level theta-e advection, enough to bring MUCAPE values
to between 500 and 900 J/kg per latest RUC analysis. 00Z TOP sounding
shows WBZ height of only 6000 ft so small hail will be easily
attainable in the stronger cells this evening. Have already received
numerous reports of pea-size hail across southern portions of the KC
metro, with hail as large as nickel size reported in Johnson Co KS.
While hail should generally remain below severe limits, low-level
helicity values are just high enough to allow for a few rotating
updrafts in the stronger cells. Will keep a close eye on any cell
that can attain any degree of mid-level rotation as this could
enhance updraft strength enough to get hail stones approaching
quarter size.
Hawblitzel
&&
.DISCUSSION...
Short range (Tonight through Tuesday night)...
The main focus for this time frame deals with the tonight period as
a powerful storm system moves across the region.
Per latest water vapor satellite imagery a strong PV anomaly was
digging into the Red River area of Oklahoma and Texas. A deep
surface low was positioned on the northern tip of this anomaly
through Kansas with an inverted surface trough nosing up the
Missouri River Valley through Iowa and Nebraska. Very warm
temperatures aloft allowed temperatures, despite limited mixing
depth, to climb into the upper 50s and perhaps low 60s across
southern and western portions of the forecast area. 12Z UA analysis
showed cold air poised just to our north ready to spill into the
area as the system shifts east this evening and tonight. The system
itself appears to be digging deeper than previously thought and with
that in mind the chances for precipitation should shift south as
well. Have therefore increased POPs quite a bit across the northern
half of the forecast area and continued to taper them to slight
chance pops across our south. As the cold air spills into the region
rain/rain showers will transition into snow from northwest to east
throughout the evening. This system should be fast moving and it
looks like by the time the deepest cold air will reach most of the
forecast area, the low will have lifted away and we end up with
relatively light, wrap around precipitation. So with the far
northwest portions of the forecast area transitioning earliest, the
snow amounts in that area are expected to the highest, which is
still expected to be around an inch or less. The limited duration
of the event elsewhere will limit accumulations to just a few tenths
of inch to around half an inch and this should mainly be confined to
northern Missouri, generally along and north of highway 36.
Once this system sweeps north and east of the forecast area quiet
weather should prevail through Tuesday. There is no real surge of
cold air at the surface in the wake of this system so for areas that
did not receive any snow temperatures should climb back to above
normal values with readings in the low to mid 40s. Temperatures may
struggle a bit in northern Missouri due to possible snow cover and
longer presence of cloud cover limiting daytime heating.
Another system will move into the Southern Plains Tuesday night and
warm advection ahead of the system may bring small chances for
rain/showers into southern sections of the forecast area. The best
chances will remain to our south and could see future updates remove
the already low POPs entirely.
CDB
Medium range (Wednesday through Sunday)...
Operational and ensemble models continue to agree on the overall
synoptic regime through the medium range with a negative height
anomaly over the middle Rio Grande valley becoming temporarily
separated from the main northerly jet; then opening up to help form
a mean longwave trough over the eastern conus as the Hudson Bay
vortex depresses equatorward and higher amplitude ridging develops
over the northeast Pacific basin. However, several important details
regarding the depth, location, and speed at which this cutoff
feature ejects eastward lead to larger uncertainty through the
period. In general, the medium range will likely be categorized by
above average temperatures into the weekend, followed by a cooling
trend to near average temperatures (then quite possible a period of
below average at an just beyond this time frame given the
hemispheric pattern).
Recent ECMWF solutions have lacked dependable continuity and have
generally been deeper and more connected to northern stream flow
with regards to the southern cut off system. However, the 12Z EC
iteration has trended significantly towards the GFS, though remains
deeper than other models and thrusts more moisture north and
displaces the sfc high pressure over the lower Missouri River
valley. GEFS members are primarily towards the slower and more
cutoff end of the spectrum keeping the system trapped into SW Texas
longer; thus have hedged closer to the operational GFS which appears
to be a good compromise. With this thinking, have kept the forecast
area dry with moisture limited to the I-44 corridor. Forecast
thicknesses and H9-H8 temperatures would suggest high temps above
average through Friday, though selectively toned back some of the
forecast given uncertainty in cloud cover, insolation, and mixing
depth. Cooler sfc high pressure will dive southeast from western
Canada through the weekend, with the bulk of the coldest air focused
into the Great Lakes. Consensus output yielded temperatures near or
slightly above average for the end of the period, yet pattern
recognition would suggest this is too warm. However, given the
inherent uncertainty for the end of the medium range, could not
justify making major revisions as of yet.
21
&&
.AVIATION...
For the 00Z TAFs...focus is on low pressure currently tracking just
south of Kansas City. To the north of the low, an area of showers will
continue to move out of eastern Kansas into northwest Missouri over
the next 2 to 3 hours. Downstream observations show all VFR cigs with
this activity, and expect any periods of MVFR to be brief and mainly
limited to visibility. Winds will quickly shift to the west-northwest
between 02Z and 03Z as a cold front pushes in from the west, with
gusts potentially exceeding 25kt overnight. A band of precipitation
behind the front will move into the area a few hours after frontal
passage, though all indications are that the southern edge of this
activity should continue to weaken and clip the KC terminals, with
better precipitation chances focused toward STJ and points north.
Thermal profiles support mostly rain with a brief transition to snow
after 06Z for the MCI-STJ corridor. At this time chances for any IFR
conditions within this band of precipitation appear low.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
607 PM CST SUN JAN 22 2012
.DISCUSSION...
/316 PM CST SUN JAN 22 2012/
MAIN CONCERN CONTINUES TO BE THE POTENTIAL FOR SEVERE THUNDERSTORMS
OVER THE AREA THIS EVENING. MOST RECENT SURFACE ANALYSIS IS SHOWING
AN OCCLUDING SURFACE LOW OVER KANSAS WITH A WARM FRONT EXTENDING
FROM CENTRAL OKLAHOMA INTO THE MID SOUTH. TEMPERATURES AND DEWPOINTS
HAVE BEEN SLOWLY RISING OVER THE CWA TODAY AND WILL CONTINUE TO DO
SO INTO EARLY THIS EVENING AS THETA-E ADVECTION INCREASES FROM THE
SOUTH IN RESPONSE TO CENTRAL PLAINS UPPER TROUGH. STILL APPEARS
THAT SHOWERS AND THUNDERSTORMS MAY DEVELOP OVER SOUTHEAST MISSOURI
INTO SOUTHERN ILLINOIS BETWEEN 22-02Z IN AREA OF STRONG 925-850MB
MOISTURE ADVECTION. MAIN CHANCE FOR SEVERE THUNDERSTORMS WILL LIKELY
OCCUR THIS EVENING WHEN VERY STRONG/DEEP ASCENT CAUSED BY THE NEGATIVELY
TILTING MID LEVEL TROUGH WILL COINCIDE WITH MODEST INSTABILITY AND
VERY STRONG DEEP LAYER SHEAR. HRRR RUNS HAVE BEEN CONSISTENT TODAY
AND REASONABLY DEPICT A LINE OF STORMS DEVELOPING QUICKLY AROUND
02Z OVER SOUTHEASTERN MISSOURI THAT MOVES NORTHEASTWARD INTO THE
FAR EASTERN CWA BY 04Z. RUC SOUNDINGS DEPICT THAT THE LOW LEVEL
INVERSION WILL WEAKEN DURING THIS PERIOD WHICH SHOULD ALLOW FOR A
DAMAGING WIND THREAT WITH THE LINE. THERE IS ALSO SOME TORNADO
THREAT WITHIN THE LINE GIVEN 0-1KM BULK SHEAR VALUES BETWEEN
0-1KM.
PRECIPITATION WILL QUICKLY MOVE OUT OF THE AREA AFTER 06Z AS THE TROUGH/
SURFACE FRONT MOVES EAST OF THE AREA. LEFT THE CHANCE OF FLURRIES OVER
NORTHERN MISSOURI INTO WEST CENTRAL ILLINOIS LATE TONIGHT INTO LATE
MORNING MONDAY ON THE SOUTH SIDE OF THE DEEPENING UPPER LOW. THEN
EXPECT DRY WEATHER UNTIL EARLY WEDNESDAY. 12Z GFS BROUGHT STRONGER
ASCENT ALONG WITH SOME QPF UP TO I-70 DURING THE DAY WEDNESDAY.
THE 12Z NAM SUPPRESSED WITH PRECIPITATION TO THE SOUTH...MOST LIKELY
BECAUSE IT IS BRINGING A NORTHERN STREAM SHORTWAVE ACROSS THE
GREAT LAKES TOO QUICKLY. THE 18Z VERSION OF THE NAM AND THE 12Z
ECMWF FAVOR THE NORTHERN PLACEMENT. PRECIPITATION ON THE NORTHERN
FRINGE OF THIS SYSTEM WILL BE LIGHT AS THERE WILL BE STEADY DRY
AIR ADVECTING INTO IT. THIS WILL ALSO LIKELY ALLOW THE RAIN TO MIX
WITH OR CHANGEOVER TO SNOW AT TIMES AS THE WET BULB REMAINS NEAR
OR BELOW ZERO.
BRITT/KANOFSKY
&&
.AVIATION...
/543 PM CST SUN JAN 22 2012/
DIFFICULT AVIATION FORECAST THIS EVENING. DRY SLOT IS MOVING UP
INTO CENTRAL MISSOURI WHICH IS SCOURING OUT THE CIGS...BUT WITH A
STRONG INVERSION MAINTAINING ITS GRIP OVER EASTERN MISSOURI AND
WESTERN ILLINOIS...I THINK IFR/LIFR CIGS WILL CONTINUE TO PREVAIL
THIS EVENING. WHAT MAY EVENTUALLY ALLOW FOR DEEPER MIXING IS
THUNDERSTORMS...MOST LIKELY ALONG AND EAST OF THE MISSISSIPPI
RIVER...BUT AM UNSURE HOW MUCH IMPROVEMENT THERE WILL BE...MOST
LIKELY HIGH IFR OR LOW MVFR. ALTERNATELY...THE CIGS MAY STICK
AROUND REGARDLESS OF ANY CONVECTION THAT DEVELOPS UNTIL THE UPPER
LEVEL LOW OVER THE EASTERN PLAINS SWINGS INTO THE MISSISSIPPI
VALLY LATER TONIGHT. THERE MAY BE A BRIEF PERIOD OF HIGHER
CIGS ONCE THIS HAPPENS...BUT THEN EXPECT CIGS TO RETURN TO IFR
UNTIL MID-MORNING MONDAY AS LOW CLOUDS SURGE INTO THE AREA BEHIND
THE COLD FRONT. LLWS WILL BE A PROBLEM ACROSS THE AREA DUE TO THE
STRONG INVERSION AND A LOW LEVEL JET OF BETWEEN 50-60KTS SCREAMING
OVERHEAD AT AROUND 2000FT. SOME OF THIS WIND WILL BEGIN TO MIX
DOWN TO THE SURFACE IF CONVECTION CAN BREAK THE INVERSION...AND
GUSTY WEST WINDS IN EXCESS OF 30KTS WILL DEVELOP BEHIND THE FRONT
ON MONDAY POTENTIALLY CAUSING CROSSWIND ISSUES FOR SMALLER AIRCRAFT.
SPECIFICS FOR KSTL...
IFR FLIGHT CONDITIONS WILL CONTINUE TO PREVAIL AT LAMBERT TONIGHT.
THERE MAY BE A SHORT REPRIEVE WITH CIGS RISING ABOVE 1000FT IF
THUNDERSTORMS CAN BREAK THE STRONG INVERSION OVER THE AREA THIS
EVENING...BUT PRIMARY THREAT FOR STORMS WILL BE EAST OF THE
TERMINAL SO I THINK CIGS WILL STAY DOWN THIS EVENING. THERE MAY
ALSO BE A SHORT PERIOD OF HIGHER CIGS ONCE THE COLD FRONT COMES
THROUGH AND ALLOWS FOR DEEPER MIXING...BUT LOW CLOUDS SHOULD SURGE
SOUTH BEHIND THE FRONT AS WELL AND BRING CIGS BACK DOWN BELOW
1000FT. LLWS WILL ALSO BE A PROBLEM THIS EVENING AS THERE IS A
LOW LEVEL JET AT 2000FT SCREAMING OVERHEAD AT 60KTS. THIS WILL
LIKELY BECOME LESS OF AN ISSUE DURING THE MID-LATE EVENING AS THE
JET MOVES EAST. THE WIND WILL SHIFT TO A SOUTHWEST DIRECTION AFTER
06Z AHEAD OF THE FRONT PRODUCING CROSS WINDS OF AROUND 20KTS ON
THE MAIN RUNWAYS...BUT CROSS WINDS SHOULD DIMINISH SOMEWHAT BEHIND
THE COLD FRONT AS THE WIND BECOMES MORE WESTERLY. GUSTY WINDS WILL
CONTINUE ON MONDAY.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
255 PM CST SAT JAN 21 2012
.DISCUSSION...
Pesky strato-cu layer finally beginning to erode from the south and
west as warmer air aloft and increased mixing eat away at the
shallow saturated zone around H9. Only RUC H9 condensation pressure
deficit forecasts have accurately depicted this cloud deck today,
and show the layer finally giving way just before sunset. Still
expecting temperatures to go nowhere this evening, then actually
begin a slow climb after midnight with waa and mixing. New stratus
layer currently over NE TX/SE OK will advect north with the leading
edge of the moisture tongue, and could potentially see some fog and
drizzle in this band. However, believe forecast soundings and
numerical guidance are underestimating soil temperatures and tend to
favor more light fog/haze with dew deposition versus reduced
visibilities/drizzle in a well mixed boundary layer. Have introduced
a patchy drizzle mention later in the morning as soundings begin to
look a bit more favorable (in addition to model qpf output), but not
expecting a persistent or widespread drizzle.
Rather potent shortwave now crossing the Sierra Nevada will eject
into the central plains Sunday afternoon allowing a nice surge of
warm, moist air throughout the forecast area. Surprisingly with
better raob sampling at 12Z, there are still discrepancies among
operational models, though the general trend is for a weaker system
ejecting and lifting out further to the northwest (roughly a
KMHK-KDSM-KMSN line). Still prefer a somewhat slower and further
south timing and position per consistent ECMWF solutions given the
jet streak remaining on the south and west side of the trough base.
This should keep the majority, if not all of the cwa in the warm
sector through most of the day, and have correspondingly went
towards the warmer guidance numbers for high temps. Some locations
could spike even warmer if more than a few peaks of sun are
realized, and would not be surprised if some locations pushed above
60F.
For the most part, warm sector rainfall and convection should remain
relegated to the middle and lower Mississippi River valley Sunday
evening, with weak frontogenesis/deformation trailing through
central Kansas. Much of the local area will be dealing with the
dryslot and downslope westerly component Sunday evening, only seeing
meager wrap around moisture and precipitation potential with the
wave lifting to the northwest. Have generally cut pops and qpf
amounts given model trends, and would not expect much more than a
dusting or few tenths of rain/snow mix over northwest and north
central Missouri by Monday morning.
Virtually no cold air exists behind this system for early next week,
such that post frontal lows Monday morning will remain above average
in a well mixed boundary layer. Dry weather can be expect Monday
with the only real concern revolving around the potential of an
elevated fire danger given dry westerly downslope sfc wind, lowering
relative humidity values, and warmer than average temperatures.
21
Medium range (Tuesday through Saturday)...
For the later half of the forecast, medium range models continue to
show a fair amount of agreement on the large scale features for next
week`s forecast. A quasi-zonal flow regime is advertised to persist
across the continent as the flow across the eastern Pacific remains
rather flat. This will continue to allow fast moving shortwaves to
jet across the nation, with a few expected to periodically
cutting-off over the Desert Southwest. This would indicate that
temperatures should remain above average over the last half of the
forecast as the majority of the cold air remains sequestered to our
north, allowing afternoon highs to range from the 40s into the 50s,
with overnight lows in the mid 20s to mid 30s.
Looking closer at the forecast specifics, mid-range models of late
have begun to settle on a solution which cuts-off a low across the
Desert Southwest early in the coming work week as energy gets dumped
from the Pacific jet into a 500mb weakness noted across northern
Mexico. This is counter to other recent solutions which advertised a
more progressive track for the shortwave energy, ultimately hinting
at precipitation chances across Kansas and Missouri in the Tuesday
to Wednesday time frame. However, with the growing consensus that
the cutoff low will develop and eject through the southern Plains,
the needed moisture and lift for any precipitation looks like it
will pass to our south, thus have only kept a silent 20% POP in for
Tuesday night.
Cutter
&&
.AVIATION...
Very low confidence throughout the 18Z taf period as models are
still struggling with mvfr cigs blanketing the area this morning;
and have significant disagreement regarding return moisture surging
north tomorrow morning. Have utilized a persistence forecast along
with RUC 925 mb condensation pressure deficits in determining the
longevity and areal extent of mvfr cigs this afternoon. Feel erosion
will take longer than models indicate, but then become rapid as
mixing within the cloud layer increases towards sunset.
Have introduced a LLWS mention overnight as a sly LLJ strengthens
with pressure falls to the west. Moisture should begin to surge
north over cooler ground leading to lower cigs overspreading the
terminals. Timing remains very uncertain and have trended towards a
period after forecast soundings would suggest, but before most
numerical guidance. Kept heights in the lower mvfr category, but
could easily see heights come in the ifr or lifr category based on
some forecast sounding data.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1145 AM CST SAT JAN 21 2012
...UPDATED AVIATION...
.DISCUSSION...
Early this morning, moisture trapped under a steep low level
inversion in the form of stratus continues to advect southeast into
the CWA. This stratus may prevent temperatures from falling into the
single digits, but also poses a significant problem for high
temperatures. The main forecast concerns are focused on precipitation
chances on Sunday and Sunday night, and on temperatures throughout
the upcoming week.
For today: weak shortwave energy moving over Missouri this morning
will quickly shift into the Ohio River valley today. Stratus is
expected to hang around for a good portion of the day as low-level
ridging axis does not slide through the area until early afternoon.
Temperatures will remain in the 20s over northern Missouri with lower
30s possible in central Missouri and eastern Kansas.
Tonight-Sunday: Our attention turns to a strong but very progressive
upper trough moving over the Pacific coastline this morning. This
upper trough is expected to pass through the region Sunday and end up
in the Great Lakes by Monday. Ahead of the wave, northward theta-e
advection will commence in earnest this evening with condensation
pressure deficit plots indicating rapid stratus development. This
stratus combined with increasing low-level warm advection should lead
to a reversal of falling overnight temperatures with readings
climbing after midnight. By 18z Sunday, surface troughing is expected
to remain just west of the CWA. With pronounced meridional flow and
an increasing surface pressure gradient, a very tricky temperature
forecast will develop. Should stratus not be as thick as anticipated,
or low- level cold advection develop later than currently forecast,
temperatures could shoot well into 50s over a large chunk of the
forecast area. Regarding the chance for precipitation, given the
progressive nature of this wave and lack of downstream blocking there
will not be enough time for deep moisture from the GOM to reach the
area, with low level trajectories pushing higher quality moisture
towards the lower Mississippi river valley. Thus, soundings reveal
only minor saturation in the lowest levels which given isentropic
lift and dynamic forcing aloft may be enough to produce light
showers ahead of the surface front Sunday afternoon. On the backside
of the upper wave there may be enough moisture to produce a fast
moving band of mixed precipitation mainly over the northwestern and
western grids before this system rotates into the Great Lakes Monday
morning.
Monday-Friday: Behind this system, little change in the overall
weather pattern is anticipated with very progressive quasi-zonal flow
continuing through the week. There remains little signal of any
organized precipitation events in the local area. Temperatures will
continue the trend of running above normal through the week.
Dux
&&
.AVIATION...
Very low confidence throughout the 18Z taf period as models are
still struggling with mvfr cigs blanketing the area this morning;
and have significant disagreement regarding return moisture surging
north tomorrow morning. Have utilized a persistence forecast along
with RUC 925 mb condensation pressure deficits in determining the
longevity and areal extent of mvfr cigs this afternoon. Feel erosion
will take longer than models indicate, but then become rapid as
mixing within the cloud layer increases towards sunset.
Have introduced a LLWS mention overnight as a sly LLJ strengthens
with pressure falls to the west. Moisture should begin to surge
north over cooler ground leading to lower cigs overspreading the
terminals. Timing remains very uncertain and have trended towards a
period after forecast soundings would suggest, but before most
numerical guidance. Kept heights in the lower mvfr category, but
could easily see heights come in the ifr or lifr category based on
some forecast sounding data.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
757 PM MST SUN JAN 22 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY...
LOW LEVEL STRATUS CONTINUES TO RETREAT TO THE DAKOTAS ACROSS THE
EAST THIS EVENING... LEAVING MOSTLY CLEAR SKIES. NAM AND MOS SKY
COVER TRENDS POINT TOWARDS THE CLOUD COVER FROM THE WEST THINNING
OUT AS IT ARRIVES AT THE GGW/TFX CWA BORDER. BLENDED THE WINDS
DOWN USING THE 22Z RUN OF THE HRRR AND 12Z RUN OF THE NAM WHICH
CAPTURES THE DEVELOPMENT OF VALLEY INVERSIONS OVERNIGHT. ALSO
TWEAKED THE MIN SURFACE TEMPERATURE TO FILTER IN THESE NEW COLD
SPOTS FROM THE VALLEY INVERSIONS. GAH
PREVIOUS SHORT TERM DISCUSSION...
A NARROW UPPER LEVEL RIDGE IS POISED JUST TO OUR WEST TO MOVE
ACROSS THE LOCAL REGION TONIGHT. THIS WILL DIMINISH THE CHANCE FOR
SNOW SHOWERS FROM THE WEST AND CREATE DRY STABLE CONDITIONS WITH
LIGHT WINDS. THERE WILL BE PERIODS OF CLEARING SKIES FROM THE WEST
THAT WILL ALLOW TEMPERATURES TO CHILL RESULTING IN SLIGHTLY BELOW
NORMAL LOWS.
MONDAY...A WEAK WARM FRONT THAT MOVES INTO NEMONT OVERNIGHT WILL
PRODUCE HIGHS NEAR NORMAL. HOWEVER THE RIDGE WILL BE PUSHED ALONG
BY A SHORTWAVE TROUGH/CLIPPER THAT WILL DESCEND INTO NORTH-
CENTRAL MONTANA. THIS WEAK COLD FRONT WILL INCREASE SKY COVER AND
COULD PRODUCE VERY LIGHT SNOW SHOWERS IN OUR WESTERN BY AFTERNOON.
WILL KEEP POPS BELOW SLIGHT CHANCE HOWEVER SINCE CONDITIONS WILL
REMAIN DRY. WINDS WILL INCREASE FROM THE NORTHWEST BEHIND THE
FRONT.
MONDAY NIGHT...THE BASE OF THE SHORTWAVE TROUGH WORKS ITS WAY
ACROSS NEMONT WITH THE POTENTIAL TO PRODUCE A FEW SNOW
SHOWERS SOUTH OF THE CWA...A FEW OF WHICH COULD AFFECT OUR
SOUTHERN ZONES. BUT CHANCES LOOK A BIT LESS THAN SLIGHT CHANCE SO
WILL NOT PUT IN FORECAST FOR NOW. THE ADDITIONAL SKY COVER COULD
KEEP LOWS A LITTLE WARMER.
TUESDAY...EXPECT DOWN-SLOPE FLOW TO CLEAR SKIES AND SUNSHINE WHICH
WILL LEAD TO SLIGHTLY ABOVE NORMAL TEMPERATURES TO DEVELOP. A
SURFACE HIGH DEVELOPS OVER SOUTHERN IDAHO LEADING TO A SOUTHWEST
BREEZE OVER NEMONT AND A MILD DAY FOR LATE JANUARY. SCT
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
NOT MANY CHANGES WERE MADE TO THE EXTENDED AND THE PATTERN AS
DESCRIBED BELOW BASICALLY STANDS. THE ONLY CHANGE WORTH NOTING WAS
THE NEED TO LOWER TEMPS NEXT SUNDAY AS LINGERING ARCTIC AIR IN THE
NORTHWEST FLOW ALOFT SHOULD HELP KEEP TEMPS DOWN. GILCHRIST
PREVIOUS DISCUSSION...SYNOPTIC SET UP...THE LONG TERM BEGINS WITH
A SPLIT FLOW PATTERN OVER THE CENTRAL PORTIONS OF THE NORTH
AMERICAN CONTINENT. ON THE SOUTHERN SIDE OF THE SPLIT... A LARGE
LOW PRESSURE CENTER EXIST OVER NORTHERN MEXICO EXTENDING NORTH
OVER THE FRONT RANGE THROUGH COLORADO. ON THE NORTHERN SIDE OF THE
SPLIT... A RIDGE RIDES UP FROM WYOMING INTO NORTHERN ALBERTA.
EASTERN MONTANA RESIDES ON THE WARMER... DRIER SIDE OF THESE TWO
FEATURES OF THE SPLIT FLOW INITIALLY. UPSTREAM OF THIS AREA FROM
THE PACIFIC NORTHWEST TRAILING INTO THE NORTH PACIFIC... ZONAL
FLOW RESIDES.
TUESDAY NIGHT THROUGH THURSDAY... THE SPLIT FLOW BEGINS TO EXIT
OFF TO THE EAST AND THE ZONAL FLOW OVER THE PACIFIC NORTHWEST
MORPHS INTO A WEAK RIDGE. VERY MINOR CHANCES FOR SHORTWAVES WILL
BE POSSIBLE BUT MOISTURE NEAR THE SURFACE WILL BE LIMITED... AND
MOST LIKELY VARIABLE MID LEVEL CLOUDS WILL BE THE ONLY RESULT.
THURSDAY NIGHT... AND UPPER LEVEL FRONT WILL PASS THROUGH THE
REGION AND MAY BE ABLE TO PULL DOWN SOME COOLER AIR FROM CENTRAL AND
AND NORTHERN ALBERTA. RAINS CHANCES WITH THIS PASSAGE WILL
INCREASE SLIGHTLY BUT QPF IF ANY IS ANTICIPATED TO BE LIGHT.
FRIDAY ONWARD...MODEL CONFIDENCE GOES FROM BAD TO WORSE FROM HERE
ON. ZONAL FLOW OVER THE NORTH PACIFIC BEGINS GENERATING UNKNOWN
WAVES OF RIDGES AND TROUGHS AND SENDING THEM ON SHORE. EACH MODEL PLAYS
WITH THE WAVES DIFFERENTLY... AND WITH A LACK OF AN ANCHORING COLD AREA
OVER THE NORTH AMERICAN CONTINENT... UNUSUAL FOR THIS TIME OF
YEAR... ANY SHORTWAVES/PRECIPITATION PRODUCERS HAVE A WILDLY
VARYING AND UNKNOWN TRACK. GAH
&&
.AVIATION...
VFR. LOW VFR CLOUDS WERE EXITING KSDY AND KGDV THIS EVENING WITH
LIGHT WINDS TO FOLLOW. CLOUDS WILL BE ON THE INCREASE LATE MONDAY
WITH LEVELS POSSIBLY DROPPING TO ABOUT 5 TO 8K FT BRIEFLY. WINDS
ARE EXPECTED TO REMAIN AT OR BELOW 10 KTS THROUGH MONDAY EVENING.
JAMBA
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1049 PM MST FRI JAN 20 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
NO APPARENT PRECIPITATION UPSTREAM AND THE HRRR MODEL KEEPS OUR
AREA DRY TONIGHT...SO REMOVED POPS FROM MOST OF THE AREA...EXCEPT A
SLIGHT CHANCE STRIP ALONG THE INTERNATIONAL BORDER. HOWEVER
TEMPERATURES UPSTREAM HAVE WARMED CONSIDERABLY. THE NAM12 MODEL
WAS USED FOR THE DIURNAL TRENDS FOR TONIGHT AND SATURDAY DUE TO
EXPECTED RISING TEMPERATURES FROM THE SW. BLENDED THE HRRR WINDS
INTO THE GRIDS TO INCREASE WINDS IN FAVORED AREAS FOR SE
DIRECTION. SCT
PREVIOUS DISCUSSION...
WARMER CONDITIONS ARE EXPECTED THIS TERM WITH ABOVE NORMAL
READINGS EXPECTED FOR THE FIRST TIME SINCE SUNDAY.
A STRONG PACIFIC SYSTEM HAS PUSHED ONSHORE IN THE PACIFIC NW WITH A
WARM FRONT NOW MOVING NE THROUGH SW MONTANA. THIS FRONT IS EXPECTED
TO CONTINUE NE ALLOWING TEMPS TO RISE TONIGHT. 850 MB TEMPS RISE
SIGNIFICANTLY AS THE REMAINING ARCTIC AIR-MASS GETS NUDGED TO OUR
NE...WITH READINGS OVER GLASGOW RISING FROM ABOUT -12*C THIS
AFTERNOON TO +3*C SATURDAY MORNING. LOW PRESSURE WILL BEGIN TO
DEVELOP OVER SOUTHERN ALBERTA SATURDAY AS THE UPPER TROUGH MOVES IN.
THE MODELS THEN TAKE THIS LOW EAST NEAR THE INTERNATIONAL
BORDER...FAR ENOUGH NORTH FOR THE MILD PACIFIC AIR-MASS TO FLOOD INTO
THE AREA SATURDAY. OF COURSE SNOW-COVER WILL TEMPER THIS WITH
FURTHER COOLING IN THE NORTHERN ZONES DUE TO LACK OF MIXING.
MOISTURE AHEAD OF THIS SYSTEM LOOKS MINIMAL SO SLIGHT CHANCE POPS
LOOK GOOD FOR NOW. MODELS SEEM TO PUT A FINGER THOUGH ON SOME
DEVELOPMENT SATURDAY AFTERNOON IN THE SOUTHEAST ZONES. THIS AREA
QUICKLY MOVES EAST TO CREATE A HEADACHE FOR AREAS THERE.
THE UPPER TROUGH LATE SATURDAY INTO SUNDAY WRAPS UP A
BIT...ESPECIALLY ON THE GFS. THIS MODEL HAS BEEN CONSISTENT AND
KNOCKS TEMPS BACK DOWN ACROSS THE AREA...AND MIXING NW WINDS TO
THE SURFACE AS WELL. SOME SNOW-SHOWER ACTIVITY CAN BE EXPECTED
TOO...SPREADING FROM NW TO SE DURING THE MORNING. SNOWFALL LOOKS
TO BE LESS THAN AN INCH. JAMBA
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
NOT TOO MANY CHANGES TO THE LONG TERM...WITH THE MAIN FOCUS BEING
THE RETURN OF THE POSSIBILITY OF ABOVE AVERAGE TEMPERATURES NEXT WEEK.
BRIEF RIDGING STILL LOOKS TO MOVE IN EARLY IN THE WORK
WEEK...FOLLOWED BY A SERIES OF SHORTWAVE TROUGHS.
DECIDED TO RAISE TEMPS A BIT FOR NEXT WEEK DUE TO THE MAJORITY OF
MODEL GUIDANCE HINTING TOWARDS WARMER TEMPERATURES COMPARED TO
PREVIOUS RUNS. THE CHALLENGE WILL STILL BE FIGURING OUT JUST HOW WARM
WE WILL GET...ESPECIALLY WITH A FEW BRIEF SHOTS OF COLD AIR WITH
THE PASSING SHORTWAVES AND CORRESPONDING COLD FRONTS. ALTHOUGH
WINDS STILL LOOK TO BE STRONG LATER IN THE PERIOD...THE AMOUNT OF
MIXING STILL MAY PREVENT US FROM BRINGING THE WARMER AIR DOWN TO
THE SURFACE. FORECASTED HIGHS ARE STILL A BIT BELOW MOST MODEL
SOLUTIONS.
WEDNESDAY STILL LOOKS TO BE THE WARMEST DAY NEXT WEEK...WITH THE
GFS BRINGING 850 TEMPS AROUND 4C TO 8C OVER THE CWA. HOWEVER...THE
12Z ECMWF SUGGESTS THAT WEDNESDAY AND THURSDAY LOOK TO BE
WARM...WITH THURSDAY BEING THE WARMER OF THE TWO DAYS. 850 TEMPS
ARE JUST A BIT HIGHER ON THURSDAY ACCORDING TO THE ECMWF BY ABOUT
2C TO 4C COMPARED TO WEDNESDAY. EITHER WAY...NEXT WEEK STILL LOOKS
TO BE A WELCOMED RETURN TO WARMER TEMPERATURES. BARNWELL
PREVIOUS LONG TERM DISCUSSION...PATTERN RETURNS TO WHAT HAS BEEN
COMMON THIS WINTER...ZONAL FLOW OFF THE PACIFIC WITH A SERIES OF
WEAK RIDGES AND TROF...AND ARCTIC AIRMASS STAYING WELL TO THE
NORTH. MODEL TIMING OF THE FEATURES NOT TOO FAR OFF FROM EACH
OTHER...ALTHOUGH THIS DOES SLIP TOWARD THE END OF THE FORECAST
PERIOD.
UPPER TROF EXITING THE REGION SUNDAY NIGHT WITH RIDGE SLIDING
ACROSS THE STATE ON MONDAY WITH ANOTHER TROF PUSHING THROUGH THE
PACIFIC NORTHWEST. COLD FRONT IS PUSHED INTO THE STATE MONDAY
NIGHT AS UPPER TROF TRACKS ALONG THE CANADIAN BORDER.
JET PUNCHES INTO WESTERN CANADA BEHIND THE TROF ON TUESDAY
NIGHT..DEVELOPING INTO A STRONG CHINOOK ACROSS MONTANA ON
WEDNESDAY. AS JET DIVES INTO THE NORTHERN PLAINS...COLD FRONT
DROPS THROUGH MONTANA...AND ENOUGH DYNAMICS AND MOISTURE FOR A
LITTLE PRECIPITATION ON WEDNESDAY. PATTERN REPEATS FOR THURSDAY
INTO THURSDAY NIGHT...ALTHOUGH AIRMASS SLIGHTLY COLDER BEHIND THIS
SECOND COLD FRONT.
POTENTIAL FOR WINDY CONDITIONS WILL BE INCREASING ALTHOUGH MIXING
WILL CONTINUE TO BE A PROBLEM...ESPECIALLY WITH INCREASED SNOW
COVER IN CONTRAST TO EARLIER IN THE MONTH. EBERT
&&
.AVIATION...
THERE WILL BE A SCATTERED TO BROKEN LAYER AROUND 2K FT AGL OVER
PARTS OF THE FORECAST AREA TONIGHT...OTHERWISE MAINLY VFR WITH
BROKEN TO OVERCAST LAYERS ABOVE 8K FT AGL. E WINDS 10 TO 15 KT AT
GGW. SLIGHT CHANCE OF A LITTLE LIGHT FREEZING RAIN LATE TONIGHT AND
SATURDAY MORNING. SIMONSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
743 PM CST SUN JAN 22 2012
.AVIATION...
00Z TAFS FOR KOMA...KLNK...KOFK.
BAND OF SNOW WITH IFR CEILINGS AND VISIBILITIES WILL CONTINUE TO
MOVE EASTWARD THIS EVENING. NORTHWEST WINDS WILL ALSO INCREASE
WE SHOULD SEE SOME BLOWING SNOW...MAINLY AT KOFK AND KLNK.
CONDITIONS SHOULD GRADUALLY IMPROVE LATE TONIGHT AND MONDAY
MORNING AS SYSTEM PULLS OFF TO THE EAST/NORTHEAST.
MILLER
&&
.PREV DISCUSSION... /ISSUED 310 PM CST SUN JAN 22 2012/
SHORT TERM...TONIGHT THROUGH WEDNESDAY.
MAIN FORECAST CHALLENGE AND CONCERN CENTERS AROUND SNOW AND
BLOWING SNOW OVERNIGHT.
STRONG MID/UPPER LEVEL TROF AXIS NOW EXTENDS ACROSS THE CENTRAL
PLAINS WITH A WEAKER SECONDARY SHORTWAVE AXIS EXTENDING ACROSS
ERN MT INTO ERN WY. AT THE SFC...LOW PRESSURE IS QUICKLY MOVING
EAST ACROSS CENTRAL KANSAS WITH AN INVERTED TROF/CDFNT EXTENDING
UP THE MISSOURI RIVER VALLEY AT 21Z. REGIONAL MOSIAC RADAR LOOP
SHOWS A WIDENING NARROW MID LEVEL FRONTOGENETICAL BAND OF LIGHT TO
MODERATE PCPN OCCURING JUST BEHIND THE BOUNDARY WITH
LIGHTER/WIDESPREAD SNOWFALL OCCURING IN BROADSCALE VERTICAL MOTION
ASSOCIATED DEFORMATION ZONE BEHIND THE FRONTOGENETIC BAND. THE DRY
SLOT OVER PORTIONS OF SOUTHEAST NEB AS EVIDENT ON SATELLITE
IMAGERY CONTINUES TO SLOWLY FILL IN THIS AFTERNOON. TEMPERATURES
AHEAD OF THE BOUNDARY HAVE JUMPED INTO THE MID TO UPPER 40S WITH
LOWER TO MID 50S IN EXTREME SOUTHEAST NEBRASKA. COLD POCKET AT
850MB IS DIRECTLY TO OUR NORTH ACROSS ERN SD PER UPPER AIR
ANALYSIS AND RUC GUIDANCE. THIS COLD POCKET WILL CONTINUE TO DRIFT
SOUTH INTO THE FORECAST AREA THROUGH EARLY EVENING...AIDING IN
QUICKLY DROPPING SFC TEMPS BELOW FREEZING BEHIND THE BOUNDARY.
PCPN WILL CONTINUE TO INCREASE FROM WEST TO EAST ACROSS THE CWA AS
THE MID/UPPER LEVEL TROF CONTINUES TO DRIFT EWD AND
BECOMES NEGATIVELY TILTED AS IT MOVES TOWARD THE MISSISSIPPI VALLEY.
FIRST PUSH IS ALREADY APPROACHING OUR FAR NWRN COUNTIES IN WELL
DEFINED MID LEVEL FRONTOGENETIC BAND EXTENDING FROM NERN NEB INTO
WRN KS. PCPN TYPE WITH THIS WILL BE TRICKY BUT AS WE LOOSE DAYLIGHT
AND ABOVE MENTIONED COLD PUSH FROM ERN SD ADVECTS DOWN...WE SHOULD
BEGIN TO TURN ANY LIQUID PCPN OVER TO SNOW RATHER QUICKLY AS WE
PROGRESS THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS. SECOND
PUSH OF LIGHT SNOW WILL COME WITH THE MORE BROADSCALE LIFT BEHIND
THE TROF IN DEFORMATION AREA. LINGERING PCPN WILL LIKELY OCCUR
AHEAD OF THE SECONDARY NRN HIGH PLAINS SHORTWAVE THROUGH THE EARLY
MONDAY MORNING HOURS.
QPF AMOUNTS ARE GENERALLY LESS THAN 0.20" IN THE NORTH AT
MOST...WITH LESS THAN 0.10" IN OUR SOUTH. GOING FORECAST HAS A
GOOD HANDLE ON SNOWFALL AMOUNTS AND CONTINUE TO THINK THAT A 1-2"
SWATH ACROSS THE NORTHERN COUNTIES WITH ABOUT 0.5" TOWARD THE I-80
CORRIDOR.
NORTHWEST WINDS WILL PICK UP BEHIND THE BOUNDARY AFTER SUNSET WITH
GUSTS NEAR 40 MPH LIKELY INTO THE OVERNIGHT. IN THE NORTH...THIS
WILL CREATE AREAS OF BLOWING SNOW AND SO GOING WINTER WEATHER
ADVISORY FOR SNOW AND BLOWING SNOW THRU 12Z STILL LOOKS GOOD. HAVE
EXPANDED THE ADVISORY SLIGHTLY SOUTH AND EAST. WITH NEAR OR LESS
THAN AN INCH OF SNOW TO THE SOUTH OF THE ADVISORY AREA...WILL HOLD
OFF ON ANY ADVISORY BUT ROADS MAY STILL BECOME SLICK WITH JUST
MINOR SNOWFALL ACCUMULATIONS.
THE SYSTEM MOVES EAST OF THE AREA ON MONDAY AND FORECAST AREA
LOOKS DRY AS WEAK UPPER RIDGING MOVES OVERHEAD. PATTERN EVOLVES
INTO A SPLIT FLOW REGIME BY TUESDAY NIGHT WITH SOUTHERN CLOSED
LOW MOVING ACROSS TEXAS AND A WEAK SHORTWAVE AXIS CROSSING THE
FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. HAVE REMOVED POPS
TUESDAY NIGHT AS SOUTHERN STREAM SYSTEM APPEARS TO BE FAR REMOVED
FROM THE FORECAST AREA TO INDUCE ANY PCPN.
KERN
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY.
PATTERN IN THE EXTENDED PERIOD BEGINS MILD AND APPEARS IT
WILL BECOME MORE NORTHWESTERLY AND COOLER TOWARD NEXT
WEEKEND...ALTHOUGH SOME QUESTION ON WHETHER IT WILL BEGIN TO
MODERATE BY DAY 7. FORECAST GENERALLY LOOKS DRY...ALTHOUGH A SMALL
PRECIP CHANCE WILL BE CARRIED IN FRIDAY PERIOD NERN ZONES. VERY
GOOD AGREEMENT EXISTED BETWEEN 12Z GFS/CMC AND 12Z/00Z ECMWF WITH A
SHORTWAVE THROUGH DRIVING A COLD FRONT ACROSS FORECAST AREA
EARLY FRIDAY. EVEN 00Z GFS ENSEMBLE MEAN WAS IN ACCORDANCE. SEVERAL
DIFFERENCES EXISTED...HOWEVER...IN EXACTLY HOW WARM WILL THURSDAY
BE...WITH CANADIAN EXCEPTIONALLY MILD...CLOSE TO +10 DEG C AT H85.
MEANWHILE 00Z ECMWF HAD FLIPPED TO A LITTLE BELOW ZERO FROM WARMER
SOLUTION YESTERDAY AND THEN BACK TO A WARMER ONE THIS MORNING. GFS
APPEARED TO BE A DECENT COMPROMISE AND COULD YIELD READINGS PER
PREVIOUS FORECAST AND LITTLE CHANGES WERE MADE. MILD TEMPERATURES
ALOFT AHEAD OF FRONT FRIDAY COULD MIX DOWN JUST AHEAD OF OR WITH
FROPA. SO ALTHOUGH MAX TEMPS WILL PROBABLY BE COOLER THAN
THURSDAY...GENERALLY LEFT HIGHS MOSTLY ABOVE 12Z MEX NUMBERS.
COOLING TREND WAS CONTINUED INTO SATURDAY AND TO SOME DEGREE INTO
SUNDAY EVEN THOUGH LATEST GFS/ECMWF SUGGESTED MODERATION BY DAY 7.
WITH UPPER FLOW STARTING NEXT WEEKEND NORTHWESTERLY...DIDN/T WANT TO
BE OVERLY OPTIMISTIC JUST YET WAITING FOR A MODERATING WAVE TO SHIFT
FLOW TO MORE WESTERLY.
CHERMOK
AVIATION...18Z TAFS FOR KOMA...KLNK...KOFK.
LOOK FOR SOME SIGNIFICANT CHANGES OVER THE NEXT 6HRS AS A COLD
FRONT MOVES THROUGH. THE WIND SHIFT IS STARTING AT KOFK TO THE
NORTHWEST...SOUTHWEST AT KLNK AND STILL FROM THE SOUTHEAST AT
KOMA. GUSTY NORTHWEST WINDS WILL EVENTUALLY MAKE THEIR WAY TO ALL
OF THE TAF SITES THROUGH 01Z AND WILL REMAIN STRONG AT 15 TO 24KTS
SUSTAINED...WITH GUSTS 25 TO 32KTS THROUGH MONDAY MORNING.
VARIABLE CIGS ARE EXPECTED THROUGH EARLY EVENING AS MVFR CIGS
BREAK OUT TO VFR AT TIMES. EVENTUALLY MVFR/IFR CIGS AND VSBYS WILL
SETTLE IN. SOME OF THE PRECIPITATION MAY START AS RAIN...THEN
CHANGE OVER TO SNOW THIS EVENING AND OVERNIGHT. THE STRONG WINDS
COMBINED WITH THE SNOW SHOULD REDUCE VSBYS TO IFR AND LOCALLY
LIFR. THE BULK OF THE FALLING SNOW SHOULD BE EAST OF THE TAFS BY
12Z WITH MVFR CIGS FOR MUCH OF THE MORNING.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR NEZ011-012-
015>018-030>034-042-043.
IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR IAZ043.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
249 PM CST SAT JAN 21 2012
.DISCUSSION...
THE RUC CONTINUES TO INDICATE WIND ADVISORY CONDITIONS DEVELOPING
ACROSS NCNTL NEB THIS AFTERNOON AS LOW PRESSURE DEEPENS ACROSS THE
HIGH PLAINS. WIND SPEEDS SHOULD PEAK DURING THE LATE AFTERNOON AND
THEN FALL OFF WITH THE LOSS OF DAYTIME HEATING.
SOUTH WINDS CONTINUE OVERNIGHT AS A STRONG PACIFIC COLD FRONT
APPROACHES THE PLAINS. THIS FRONT WILL SWEEP THROUGH THE FCST AREA
SUNDAY MORNING AND LOW PRESSURE WILL CONSOLIDATE ACROSS THE
MIDWEST. STRONG NORTHWEST WINDS WILL DEVELOP BEHIND THE SFC LOW
ASSOCIATED WITH PACIFIC HIGH PRESSURE. A BLEND OF MAV AND MET
GUIDANCE PRODUCED HIGH END WIND ADVISORY CONDITIONS. DEUEL COUNTY
COULD PERHAPS REACH HIGH WIND CATEGORY BUT THAT IS LIKELY A RESULT
OF WEIGHTING FACTORS ASSOCIATED WITH THE DATA FROM KSNY. THE NAM
INDICATED GUSTS TO 55 MPH BUT ONLY ACROSS A SMALL PART OF CHERRY
COUNTY. WINDS ARE EXPECTED TO STAY UP EAST OF HIGHWAY 83 SUNDAY
EVENING FOR A FEW HOURS AS WRAP AROUND STRATUS PRODUCES A SHALLOW
MIXED LAYER. WIND SPEEDS SHOULD DECLINE BETWEEN 03Z AND 06Z AS THE
SFC LOW WILL PRESUMABLY BE FAR ENOUGH EAST FOR THE WINDS TO RELAX.
ELSEWHERE WINDS SHOULD DROP OFF QUICKLY AS A CLEARING LINE MOVES
EAST TO NEAR HIGHWAY 83 BY 00Z MONDAY.
A BLEND OF ECMWF...GEM REGIONAL...NAM AND GFS WAS USED FOR QPF
AMOUNTS WHICH ARE GENERALLY 1/10 OF INCH OR LESS. NOTE THE QPF IS
POST FRONTAL AND THE PTYPE IS SNOW. WITH THE H700MB LOW TRACKING
THROUGH THE NRN PLAINS...SNOW SHOWERS WOULD APPEAR TO BE THE
DOMINANT STORM MODE BUT WE MAY BE DEALING WITH A MIXED MODE AT TIMES.
THE NAM AND GFS ALSO KEEP THE FCST AREA MOSTLY DRY SO POPS ARE CHC
CATEGORY. HPC FAVORED THE GEM MODEL AND THE UKMET. THE ECMWF
APPEARED TO BE THE WETTER SOLN. THE GEM REGIONAL DEVELOPS A WEDGE
OF WARP AROUND QPF ACROSS THE ERN ZONES AMOUNTING TO 1/3 OF AN
INCH. GIVEN THE STRONG WINDS...SIGNIFICANT BLOWING SNOW WOULD
DEVELOP IF THAT WERE TO VERIFY.
HIGH PRESSURE SETTLES OVER THE FCST AREA MONDAY MORNING THROUGH TUESDAY.
A SPLIT IN THE WESTERLIES DEVELOPS SENDING A LARGE UPPER LEVEL CUTOFF
LOW THROUGH THE SRN PLAINS TUESDAY THROUGH FRIDAY. THIS SYSTEM
WILL HAVE LITTLE OR NO EFFECT ON THE SENSIBLE WEATHER ACROSS THE FCST
AREA EXCEPT TO HOLD PACIFIC HIGH PRESSURE IN PLACE. DEEP LOW PRESSURE
CIRCULATING THROUGH CNTL AND SRN CANADA WILL ALSO DRAW PACIFIC
HIGH PRESSURE THROUGH THE CNTL PLAINS WEDNESDAY AND THURSDAY
BEFORE ANOTHER STRONG PACIFIC COLD FRONT DROPS THROUGH THURSDAY
NIGHT OR FRIDAY.
THE FCST IS DRY MONDAY THROUGH SUNDAY. THE GFS IS AMPLIFYING A
DISTURBANCE THRU THE FCST AREA SATURDAY BUT IT APPEARS TO BE TOO
FAST. THE ECMWF HOLDS THAT FEATURE OFFSHORE IN THE PACIFIC.
&&
.AVIATION...
WINDS WILL DECREASE TONIGHT AS THE PRESSURE GRADIENT EASES. THEN...A
COLD FRONT WILL MOVE EAST ACROSS NEBRASKA TONIGHT...BRINGING A WIND
SHIFT TO THE NORTHWEST BY 12Z AT BOTH KVTN AND KLBF. THE WIND SPEEDS
WILL INCREASE THROUGH THE DAY...WITH GUSTS UPWARDS OF 35 TO 40KTS BY
LATE MORNING AS COLD AIR ADVECTION AIDES IN STRONGER WINDS ALOFT
BEING ABLE TO BE MIXED TO THE SURFACE. IN ADDITION...THERE DOES LOOK
TO BE SOME PRECIPITATION BEHIND THE FRONT...WHICH MAY MOVE INTO THE
KVTN TERMINAL IN THE MORNING HOURS. HAVE TRENDED THE FORECAST TO
INCLUDE A CEILING DROPPING TO MVFR...ALONG WITH DECREASED
VISIBILITIES DUE TO -SN IN THE LATE MORNING. TIMING MAY NEED TO BE
ADJUSTED IN FOLLOWING FORECASTS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY FROM 6 AM CST
/5 AM MST/ TO 6 PM CST /5 PM MST/ SUNDAY FOR
NEZ004-005-022>025-035>037-056>059-069>071-094.
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR
NEZ005>010-094.
WIND ADVISORY FROM 9 AM TO 9 PM CST SUNDAY FOR NEZ006>010-
026>029-038.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1138 AM CST SAT JAN 21 2012
.AVIATION... /FOR THE 18Z TAF ISSUANCE/
THE NEXT 24 HOURS WILL BE BUSY FOR AVIATION CONCERNS. STRONG
SOUTHERLY WINDS WILL BE OBSERVED THROUGH THE REMAINDER OF THE
AFTERNOON AS A TIGHT PRESSURE GRADIENT HAS SET UP ACROSS THE AREA
AHEAD OF A STATIONARY FRONT OVER THE EASTERN PARTS OF WYOMING AND
COLORADO. WINDS AT 850MB AT THE MRRN1 PROFILER IN NORTHWEST
CHERRY COUNTY WERE 50KTS AT 15Z...WITH LESSER SPEEDS GOING SOUTH.
ASSUMING THERE WILL BE SOME MIXING THIS AFTERNOON...PLAN ON
SUSTAINED WINDS RANGING FROM AROUND 20 KT IN SOUTHWEST NEBRASKA TO
28KTS IN NORTHERN NEBRASKA...WITH GUSTS OF 25 TO 35KTS.
THE FRONT TO THE WEST WILL MOVE EAST ACROSS NEBRASKA
TONIGHT...ALLEVIATING THE PRESSURE GRADIENT AND ALLOWING WINDS TO
DECREASE A BIT OVERNIGHT. BEHIND THE FRONT...WINDS WILL SHIFT TO
THE NORTHWEST AND INCREASE. THE WIND SHIFT SHOULD REACH BOTH KVTN
AND KLBF BY 12Z...WITH AN INCREASING TREND THROUGH THE MORNING. BY
LATE MORNING COULD SEE GUSTS UPWARDS OF 35 TO 40KTS AS COLD AIR
ADVECTION AIDES IN STRONGER WINDS ALOFT BEING ABLE TO BE MIXED TO
THE SURFACE. IN ADDITION...THERE DOES LOOK TO BE SOME
PRECIPITATION BEHIND THE FRONT...WHICH MAY MOVE INTO THE KVTN
TERMINAL IN THE MORNING HOURS. HAVE TRENDED THE FORECAST TO
INCLUDE A CEILING DROPPING TO IFR...ALONG WITH DECREASED
VISIBILITIES WITH -SN IN THE LATTER PARTS OF THE FORECAST PERIOD.
TIMING MAY NEED TO BE ADJUSTED IN FOLLOWING FORECASTS.
&&
.PREV DISCUSSION... /ISSUED 1043 AM CST SAT JAN 21 2012/
UPDATE...
SFC WINDS ARE ON THE WAY UP THIS MORNING WITH LOW PRESSURE DEEPENING
ACROSS THE HIGH PLAINS. MERRIMAN PROFILER SHOWING 50KT AT THE
LOWEST GATE. THE RUC SHOWS THIS BANK OF STRONG WINDS SHIFTING EAST
AND MIXING DOWN THIS AFTERNOON SO A WIND ADVISORY IS IN PLACE FROM
WRN CHERRY EAST. KICR GUSTED TO 40KT AT 1546UTC AND THIS APPEARS
TO BE A SIGN OF THINGS TO COME.
PREV DISCUSSION... /ISSUED 400 AM CST SAT JAN 21 2012/
SYNOPSIS...
ARCTIC 1026 MB HIGH PRESSURE CENTERED OVER MINNESOTA THIS
MORNING...AND SLIDING SOUTHEAST. WINDS HAVE BECOME SOUTH TO
SOUTHWEST OVER THE CWA...WITH TEMPS IN THE LOWER TEENS. SATELLITE
SHOWING SOME LOW STRATUS OVER PARTS OF CENTRAL AND EASTERN
NEBRASKA. WATER VAPOR IMAGERY SHOW SPLIT FLOW CONTINUING WITH
WESTERN CONUS SYSTEM SPLITTING.
DISCUSSION...
WITH THE HIGH FINALLY MOVING TO THE SOUTHEAST...AND RETURN
SOUTHERLY FLOW...SHOULD BE ABLE TO WARM MOST OF THE CWA UP TODAY.
GUIDANCE IN GOOD AGREEMENT WITH 40S OVER WESTERN ZONES...30S
EAST. HOWEVER WITH THE WARMER TEMPS WILL COME GUSTY WINDS. TIGHT
PRESSURE GRADIENT...WITH 3 HR PRESSURE FALLS AROUND 6 MB. MOS AND
RAW MODEL DATA KEEPS WINDS BELOW GUIDANCE...AND FORECAST
FOLLOWS...HOWEVER WILL NEED TO MONITOR. HIGHEST WINDS AT 850 MB
APPROACH 60 KTS OVER NORTH CENTRAL...HOWEVER DO NOT EXPECT TO
FULL MIX WHERE THE STRONGEST WINDS ALOFT ARE.
TONIGHT THE NEXT LOW PRESSURE SYSTEM WILL CROSS THE NORTHERN
ROCKIES...AND PUSH ONTO THE PLAINS. LOWER LEVELS ON THE DRY SIDE
INITIALLY AND WILL NEED TO SATURATE TOP DOWN. THIS WILL LIKELY
LIMIT THE AMOUNT OF QPF TO REACH THE GROUND. MIXING WILL KEEP
TEMPS UP AND HAVE KEEP A MIX OF PRECIP BEFORE 06Z. AFTER 00Z COLD
FRONT SHOULD BE CROSS THE AREA...WITH A CHANGE OVER TO SNOW. LIFT
IS FOCUSED MORE TO THE NORTH...WITH ONLY VERY LIGHT ACCUMULATIONS
EXPECTED...AT BEST. WITH THE CLOUDS EXPECT LOWS TO REMAIN
MILD...IN THE 20S.
SUNDAY COLD FRONT SHOULD PUSH ACROSS THE AREA EARLY. STRONG NW
WINDS DEVELOP BEHIND THE FRONT...ALONG WITH THE CONTINUE SLIGHT
CHANCE FOR PRECIP. WET BULB EFFECT...PER MODEL SOUNDING
ANALYSIS...SHOULD RESULT IN ANY PRECIP IN THE FORM AS
SNOW...HOWEVER WITH TEMPS WELL INTO THE 30S...POSSIBLY 40 FOR
SUNDAY...COULD BRIEFLY SEE A MIX. MORE OF A CONCERN IS THE STRONG
WINDS. WIND ADVISORY IS PROBABLE...HOWEVER WITH THE CHANCE FOR
PRECIP...WILL HOLD OFF ON ANY HEADLINE AS MAY NEED TO INCORPORATE
LIGHT SNOW INTO THE HEADLINE.
ACTIVE PATTERN FOR NEXT WEEK...HOWEVER LIMITED MOISTURE TO WORK
WITH OVER THE CWA. SEVERAL WAVES TO PUSH ACROSS THE PLAINS...WITH
A STRONG WAVE TO PUSH ACROSS THE SOUTHERN PLAINS MONDAY NIGHT
THROUGH TUESDAY. ARCTIC AIR TO RETREAT NORTH WITH SEASONAL
CONDITIONS EXPECTED THROUGH MUCH OF THE WEEK. HIGHS IN THE 40S
WITH POSSIBLY 50S FOR THURSDAY AHEAD OF THE NEXT COLD FRONT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 6 PM CST /5
PM MST/ THIS EVENING FOR NEZ005>010-094.
&&
$$
SHORT TERM/EXTENDED...99
AVIATION...99
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1043 AM CST SAT JAN 21 2012
.UPDATE...
SFC WINDS ARE ON THE WAY UP THIS MORNING WITH LOW PRESSURE DEEPENING
ACROSS THE HIGH PLAINS. MERRIMAN PROFILER SHOWING 50KT AT THE
LOWEST GATE. THE RUC SHOWS THIS BANK OF STRONG WINDS SHIFTING EAST
AND MIXING DOWN THIS AFTERNOON SO A WIND ADVISORY IS IN PLACE FROM
WRN CHERRY EAST. KICR GUSTED TO 40KT AT 1546UTC AND THIS APPEARS
TO BE A SIGN OF THINGS TO COME.
&&
.PREV DISCUSSION... /ISSUED 549 AM CST SAT JAN 21 2012/
AVIATION...
UNRESTRICTED CEILING AND VISIBILITY IS LIKELY IN CENTRAL AND
WESTERN NEBRASKA THROUGH THE NIGHT TONIGHT AND INTO EARLY SUNDAY.
AFTER ABOUT 15Z WIND OVER CENTRAL AND WESTERN NEBRASKA WILL
INCREASE AND BECOME 170-200 AND WINDY. WIND SPEEDS IN THE NORTH WILL
BE 18-21G27-31KT AND IN THE NORTH 16-18G24-28KT.
LOOKING BEYOND 12Z SUNDAY...WIND IS LIKELY TO BE EVEN STRONGER
AND OUT OF THE NORTH TO NORTHWEST OVER THE AREA LATE MORNING THROUGH
EARLY AFTERNOON.
PREV DISCUSSION... /ISSUED 400 AM CST SAT JAN 21 2012/
SYNOPSIS...
ARCTIC 1026 MB HIGH PRESSURE CENTERED OVER MINNESOTA THIS
MORNING...AND SLIDING SOUTHEAST. WINDS HAVE BECOME SOUTH TO
SOUTHWEST OVER THE CWA...WITH TEMPS IN THE LOWER TEENS. SATELLITE
SHOWING SOME LOW STRATUS OVER PARTS OF CENTRAL AND EASTERN
NEBRASKA. WATER VAPOR IMAGERY SHOW SPLIT FLOW CONTINUING WITH
WESTERN CONUS SYSTEM SPLITTING.
DISCUSSION...
WITH THE HIGH FINALLY MOVING TO THE SOUTHEAST...AND RETURN
SOUTHERLY FLOW...SHOULD BE ABLE TO WARM MOST OF THE CWA UP TODAY.
GUIDANCE IN GOOD AGREEMENT WITH 40S OVER WESTERN ZONES...30S
EAST. HOWEVER WITH THE WARMER TEMPS WILL COME GUSTY WINDS. TIGHT
PRESSURE GRADIENT...WITH 3 HR PRESSURE FALLS AROUND 6 MB. MOS AND
RAW MODEL DATA KEEPS WINDS BELOW GUIDANCE...AND FORECAST
FOLLOWS...HOWEVER WILL NEED TO MONITOR. HIGHEST WINDS AT 850 MB
APPROACH 60 KTS OVER NORTH CENTRAL...HOWEVER DO NOT EXPECT TO
FULL MIX WHERE THE STRONGEST WINDS ALOFT ARE.
TONIGHT THE NEXT LOW PRESSURE SYSTEM WILL CROSS THE NORTHERN
ROCKIES...AND PUSH ONTO THE PLAINS. LOWER LEVELS ON THE DRY SIDE
INITIALLY AND WILL NEED TO SATURATE TOP DOWN. THIS WILL LIKELY
LIMIT THE AMOUNT OF QPF TO REACH THE GROUND. MIXING WILL KEEP
TEMPS UP AND HAVE KEEP A MIX OF PRECIP BEFORE 06Z. AFTER 00Z COLD
FRONT SHOULD BE CROSS THE AREA...WITH A CHANGE OVER TO SNOW. LIFT
IS FOCUSED MORE TO THE NORTH...WITH ONLY VERY LIGHT ACCUMULATIONS
EXPECTED...AT BEST. WITH THE CLOUDS EXPECT LOWS TO REMAIN
MILD...IN THE 20S.
SUNDAY COLD FRONT SHOULD PUSH ACROSS THE AREA EARLY. STRONG NW
WINDS DEVELOP BEHIND THE FRONT...ALONG WITH THE CONTINUE SLIGHT
CHANCE FOR PRECIP. WET BULB EFFECT...PER MODEL SOUNDING
ANALYSIS...SHOULD RESULT IN ANY PRECIP IN THE FORM AS
SNOW...HOWEVER WITH TEMPS WELL INTO THE 30S...POSSIBLY 40 FOR
SUNDAY...COULD BRIEFLY SEE A MIX. MORE OF A CONCERN IS THE STRONG
WINDS. WIND ADVISORY IS PROBABLE...HOWEVER WITH THE CHANCE FOR
PRECIP...WILL HOLD OFF ON ANY HEADLINE AS MAY NEED TO INCORPORATE
LIGHT SNOW INTO THE HEADLINE.
ACTIVE PATTERN FOR NEXT WEEK...HOWEVER LIMITED MOISTURE TO WORK
WITH OVER THE CWA. SEVERAL WAVES TO PUSH ACROSS THE PLAINS...WITH
A STRONG WAVE TO PUSH ACROSS THE SOUTHERN PLAINS MONDAY NIGHT
THROUGH TUESDAY. ARCTIC AIR TO RETREAT NORTH WITH SEASONAL
CONDITIONS EXPECTED THROUGH MUCH OF THE WEEK. HIGHS IN THE 40S
WITH POSSIBLY 50S FOR THURSDAY AHEAD OF THE NEXT COLD FRONT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 6 PM CST
/5 PM MST/ THIS EVENING FOR NEZ005>010-094.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1109 PM CST FRI JAN 20 2012
.AVIATION...06Z TAF. DRY CONDITIONS EXPECTED FOR THIS TAF
PERIOD...WITH MAIN CONCERNS LYING WITH CLOUD COVER EARLY ON...THEN
A SWITCH IN WINDS. CURRENTLY SEEING A SMALL AREA OF LOW LEVEL
STRATUS LINGERING OVER THE TERMINAL AREA...RESULTING IN MVFR CIGS.
COULD SEE THIS CONTINUE FOR A FEW MORE HOURS...BUT IS EXPECTED TO
DIMINISH WITH VFR CONDITIONS RETURNING. THROUGH THE REST OF THE
TAF PERIOD ANY CLOUD COVER IS EXPECTED TO REMAIN CONFINED TO THE
MID/UPPER LEVELS. AS FAR AS WINDS GO...SPEEDS CONTINUE TO DIMINISH
AS SURFACE HIGH PRESSURE DRIFTS EAST THROUGH THE AREA. LATER THIS
MORNING WINDS WILL GRADUALLY SWITCH TO THE SOUTH ON THE BACKSIDE
OF THE SFC HIGH...AND WILL REMAIN SOUTHERLY THROUGH THE REMAINDER
OF THE TAF PERIOD. A TIGHTENING PRESSURE GRADIENT DEVELOPING
ACROSS THE AREA WILL BRING INCREASING SPEEDS THROUGH THE DAYTIME
HOURS...WITH SPEEDS THIS AFTERNOON REACHING NEAR 20 TO 25 MPH WITH
HIGHER GUSTS.
&&
.PREV DISCUSSION... /ISSUED 1023 PM CST FRI JAN 20 2012/
UPDATE...SOME STRATUS IS MAKING ITS WAY FROM THE NORTH BUT SHOULD
EVENTUALLY HAVE A HARD TIME HOLDING TOGETHER DURING THE
OVERNIGHT...BUT HAVE INCREASED SKY COVER FOR THE NEXT SEVERAL
HOURS. ALSO RAISED TEMPERATURES A BIT...ESPECIALLY IN THE
SOUTHWESTERN CWA FOR LOWS TONIGHT.
PREV DISCUSSION... /ISSUED 318 PM CST FRI JAN 20 2012/
SHORT TERM...THROUGH 00Z SUNDAY. MORNING UPPER AIR ANALYSIS
INDICATES ZONAL TO NORTHWESTERLY UPPER LEVEL FLOW PERSISTING
ACROSS MUCH OF THE CONUS. A 90KT MID LEVEL JET AXIS IS ALSO NOTED
EXTENDING FROM THE NORTHERN PLAINS TO THE MID-ATLANTIC. WATER
VAPOR IMAGERY INDICATES INCREASED MID LEVEL MOISTURE ACROSS THE
NORTHERN HALF OF THE CONUS...WITH A TROPICAL MID LEVEL MOISTURE
TAP ALSO NOTED APPROACHING NORTHWESTERN MEXICO FROM THE PACIFIC.
AT THE SURFACE A RIDGE OF HIGH PRESSURE REMAINS ANCHORED ACROSS
MUCH OF THE PLAINS...WITH AFTERNOON TEMPERATURES REMAINING IN THE
20S ACROSS MUCH OF THE CENTRAL PLAINS. WARMER AIR IS NOT FAR AWAY
HOWEVER AS A STRONG LOW LEVEL BAROCLINIC ZONE CURRENTLY EXTENDS
ALONG MUCH OF THE HIGH PLAINS...WITH A 20-30 DEGREE TEMPERATURE
GRADIENT CURRENTLY EXISTING WITHIN ABOUT 50 MILES ACROSS THE LOW
LEVEL BAROCLINIC ZONE.
MID AFTERNOON SATELLITE IMAGERY INDICATES ALTO-STRATUS OVER SOUTH
DAKOTA...MOVING SOUTH/SOUTHEAST INTO NORTHERN NEBRASKA. SATELLITE
IMAGERY ALSO INDICATES THE WESTERN EDGE OF THIS CLOUD DECK IS
ERODING...THUS MAKING IT APPEAR AS THOUGH WE STAND A BETTER CHANCE
OF RECEIVING A GLANCING BLOW ACROSS OUR NORTHEASTERN CWA RATHER THAN
BE COMPLETELY OVERTAKEN BY CLOUDS THIS EVENING. THIS ALSO FITS
WELL WITH THE LATEST RUC GUIDANCE...WHICH INDICATES ISENTROPIC
DOWN GLIDE IS INFILTRATING MUCH OF THE REGION. GIVEN ALL
THIS...WILL KEEP MOSTLY CLOUDY SKIES GOING ACROSS OUR NORTHEAST
THROUGH LATE EVENING...WITH LOCATIONS FARTHER SOUTHWEST HOPEFULLY
REMAINING WEST/SOUTHWEST OF THE CLOUD DECK. THIS WILL BE SOMETHING
FOR THE EVENING SHIFT TO MONITOR HOWEVER...JUST IN CASE THE CLOUD
DECK DOES MANAGE TO PUSH FARTHER SOUTHWEST THAN CURRENTLY
FORECAST.
CLEARING SKIES...DECREASING LOW LEVEL WINDS AND WEAK SURFACE RIDGING
SHOULD PROMOTE A DECENT DROP OFF IN TEMPERATURES TONIGHT AND
CURRENTLY HAVE 20-25 DEGREE DROP OFFS IN THE FORECAST...WHICH YIELDS
OVERNIGHT LOWS IN THE SINGLE DIGITS. THE SURFACE RIDGE IS EXPECTED
TO PUSH OFF TO THE EAST EARLY SATURDAY MORNING...WITH LOW LEVEL
RETURN FLOW REESTABLISHED ACROSS THE CENTRAL PLAINS BY SUNRISE
SATURDAY. THIS LOW LEVEL RETURN FLOW WILL PROMOTE WEAK LOW LEVEL
WAA WITHIN A SOUTH/SOUTHEASTERLY LOW LEVEL WIND FIELD. ~25 DEGREE
RISES ARE EXPECTED FOR THE MOST PART SATURDAY...WHICH YIELDS
SATURDAY AFTERNOON HIGHS IN THE UPPER 20S TO UPPER 30S ACROSS THE
CWA.
LONG TERM...00Z SUNDAY THROUGH FRIDAY. THE START OF THE LONG TERM
PERIOD WILL FEATURE AN H5 RIDGE ACROSS THE CENTRAL UNITED STATES
WITH A LARGE TROUGH IN THE WEST. THERE IS GENERAL CONSENSUS THAT
THE WESTERN U.S. TROUGH WILL MOVE ACROSS THE CENTRAL PLAINS LATE
SATURDAY NIGHT INTO SUNDAY...HOWEVER FINDING AGREEMENT IN THE
DETAILS REMAINS ELUSIVE. DIFFERENCES REMAIN AMONGST THE VARIOUS
MODEL SOLUTIONS IN THE OVERALL STRENGTH/TIMING WHICH OBVIOUSLY HAVE
LARGE IMPACTS IN REGARDS TO POPS AND PRECIPITATION TYPE. AT THIS
POINT...HAVE CONTINUED TO CARRY A BLENDED MODEL SOLUTION WHICH GIVES
POPS GENERALLY IN THE 30 PERCENT RANGE ON SUNDAY. THIS ALSO LINGERS
A POP IN THE FAR EAST FOR SUNDAY EVENING WHICH ACCOUNTS FOR SOME OF
THE SLOWER MODEL SOLUTIONS...IN PARTICULAR THE ECMWF.
TEMPERATURES AND THE OVERALL THERMAL PROFILE REMAINS UNCERTAIN
THOUGH THE GENERAL TREND SEEMS TO KEEP WARMER H85 TEMPERATURES IN
THE MORNING...FOLLOWED BY COLDER AIR ARRIVING BEHIND A COLD FRONT IN
THE AFTERNOON. IF PRECIPITATION STARTS EARLY ENOUGH ON
SUNDAY...COULD SEE SOME POTENTIAL FOR LIGHT FREEZING RAIN DUE TO THE
EXPECTED BELOW FREEZING SURFACE TEMPERATURES...BUT WITH CONFIDENCE
STILL SO LOW IN THE DETAILS...WILL INSTEAD OPT FOR A RAIN/SNOW MIX.
IN FACT...COULD SEE SOME JUSTIFICATION FOR A RAIN/SNOW MIX MUCH OF
THE DAY DEPENDING ON THE TIMING OF THE COLDER AIR ALOFT. IN REGARDS
TO SUNDAY EVENING...WILL GO WITH SNOW SINCE MOST SOLUTIONS HAVE THE
COLD AIR IN PLACE BY THAT TIME.
ANOTHER CONCERN ON SUNDAY WILL BE STRONG WINDS BEHIND THE COLD
FRONT. STRONG PRESSURE RISES ARE SHOWN ACROSS THE FORECAST AREA.
MOMENTUM TRANSFER FROM NAM BUFR SOUNDINGS SUGGEST GUSTS COULD
APPROACH 40 KTS ACROSS MUCH OF THE FORECAST AREA...WITH EVEN
STRONGER WINDS POTENTIALLY TAKING HOLD IN THE SOUTHWEST. CURRENTLY
WE ARE HIGHLIGHTING THE STRONGER WINDS IN THE HAZARDOUS WEATHER
OUTLOOK...AND WILL LET THAT WORDING CONTINUE.
A DRY PERIOD TAKES HOLD AGAIN FOR OVERNIGHT SUNDAY INTO AT LEAST
EARLY TUESDAY AS ANOTHER H5 RIDGE DOMINATES THE CENTRAL PORTION OF
THE COUNTRY. THE NEXT WAVE MOVES THROUGH THE AREA TUESDAY INTO
TUESDAY NIGHT...HOWEVER AGAIN THERE ARE DIFFERENCES IN TIMING
AMONGST THE MODELS. WILL MAINTAIN CONTINUITY FOR NOW AND HOLD ONTO
THE MAIN PRECIPITATION CHANCES TUESDAY NIGHT. PRECIPITATION TYPE
COULD AGAIN BE AN WITH THE GFS COLDER THAN THE ECMWF. HAVE GONE
WITH A RAIN/SNOW COMBINATION IN THE SOUTH...BUT WILL GO ALL SNOW IN
THE NORTH WHERE EVEN THE WARMER ECMWF DROPS H85 TEMPERATURES BELOW
FREEZING TUESDAY EVENING.
THE REMAINDER OF THE FORECAST PERIOD APPEARS TO BE GENERALLY SUPPORT
ABOVE NORMAL TEMPERATURES WITH HIGHS PRIMARILY IN THE 40S. THE
WARMEST DAY COULD TURN OUT TO BE THURSDAY WITH SOME LOCATIONS
POTENTIALLY PUSHING THE 50 DEGREE MARK.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ADO
UPDATE...HEINLEIN
SHORT...BRYANT
LONG...KING
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1023 PM CST FRI JAN 20 2012
.UPDATE...SOME STRATUS IS MAKING ITS WAY FROM THE NORTH BUT SHOULD
EVENTUALLY HAVE A HARD TIME HOLDING TOGETHER DURING THE
OVERNIGHT...BUT HAVE INCREASED SKY COVER FOR THE NEXT SEVERAL
HOURS. ALSO RAISED TEMPERATURES A BIT...ESPECIALLY IN THE
SOUTHWESTERN CWA FOR LOWS TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 510 PM CST FRI JAN 20 2012/
AVIATION...00Z KGRI TAF. CEILINGS ARE GOING TO BE A TOUGH CALL
THIS EVENING. SOME STRATUS ARE HEADING TOWARD THE TERMINAL FROM
THE NORTH...BUT ISENTROPIC DOWNGLIDE WILL BE COMPETING AGAINST
THE STRATUS HOLDING TOGETHER FOR LONG. LOOKING AT THE LATEST
SATELLITE DATA AND SPEED TOOLS...IT APPEARS THAT THE STRATUS
SHOULD ARRIVE A BIT OVER AN HOUR AFTER THIS FORECAST IF
VALID...BUT WITH ISENTROPIC DOWNGLIDE...WILL LIKELY ONLY HOLD
TOGETHER THROUGH THE EVENING AND THEN SCATTER BY THE EARLY
OVERNIGHT. WIND WILL SWITCH FROM THE NORTH TO THE SOUTH OVERNIGHT
AS A SURFACE HIGH SLIDES EAST. SOUTH WIND CAN GET A BIT GUSTY BY
SATURDAY AFTERNOON AS THE SURFACE PRESSURE GRADIENT INCREASES.
PREV DISCUSSION... /ISSUED 318 PM CST FRI JAN 20 2012/
SHORT TERM...THROUGH 00Z SUNDAY. MORNING UPPER AIR ANALYSIS
INDICATES ZONAL TO NORTHWESTERLY UPPER LEVEL FLOW PERSISTING
ACROSS MUCH OF THE CONUS. A 90KT MID LEVEL JET AXIS IS ALSO NOTED
EXTENDING FROM THE NORTHERN PLAINS TO THE MID-ATLANTIC. WATER
VAPOR IMAGERY INDICATES INCREASED MID LEVEL MOISTURE ACROSS THE
NORTHERN HALF OF THE CONUS...WITH A TROPICAL MID LEVEL MOISTURE
TAP ALSO NOTED APPROACHING NORTHWESTERN MEXICO FROM THE PACIFIC.
AT THE SURFACE A RIDGE OF HIGH PRESSURE REMAINS ANCHORED ACROSS
MUCH OF THE PLAINS...WITH AFTERNOON TEMPERATURES REMAINING IN THE
20S ACROSS MUCH OF THE CENTRAL PLAINS. WARMER AIR IS NOT FAR AWAY
HOWEVER AS A STRONG LOW LEVEL BAROCLINIC ZONE CURRENTLY EXTENDS
ALONG MUCH OF THE HIGH PLAINS...WITH A 20-30 DEGREE TEMPERATURE
GRADIENT CURRENTLY EXISTING WITHIN ABOUT 50 MILES ACROSS THE LOW
LEVEL BAROCLINIC ZONE.
MID AFTERNOON SATELLITE IMAGERY INDICATES ALTO-STRATUS OVER SOUTH
DAKOTA...MOVING SOUTH/SOUTHEAST INTO NORTHERN NEBRASKA. SATELLITE
IMAGERY ALSO INDICATES THE WESTERN EDGE OF THIS CLOUD DECK IS
ERODING...THUS MAKING IT APPEAR AS THOUGH WE STAND A BETTER CHANCE
OF RECEIVING A GLANCING BLOW ACROSS OUR NORTHEASTERN CWA RATHER THAN
BE COMPLETELY OVERTAKEN BY CLOUDS THIS EVENING. THIS ALSO FITS
WELL WITH THE LATEST RUC GUIDANCE...WHICH INDICATES ISENTROPIC
DOWN GLIDE IS INFILTRATING MUCH OF THE REGION. GIVEN ALL
THIS...WILL KEEP MOSTLY CLOUDY SKIES GOING ACROSS OUR NORTHEAST
THROUGH LATE EVENING...WITH LOCATIONS FARTHER SOUTHWEST HOPEFULLY
REMAINING WEST/SOUTHWEST OF THE CLOUD DECK. THIS WILL BE SOMETHING
FOR THE EVENING SHIFT TO MONITOR HOWEVER...JUST IN CASE THE CLOUD
DECK DOES MANAGE TO PUSH FARTHER SOUTHWEST THAN CURRENTLY
FORECAST.
CLEARING SKIES...DECREASING LOW LEVEL WINDS AND WEAK SURFACE RIDGING
SHOULD PROMOTE A DECENT DROP OFF IN TEMPERATURES TONIGHT AND
CURRENTLY HAVE 20-25 DEGREE DROP OFFS IN THE FORECAST...WHICH YIELDS
OVERNIGHT LOWS IN THE SINGLE DIGITS. THE SURFACE RIDGE IS EXPECTED
TO PUSH OFF TO THE EAST EARLY SATURDAY MORNING...WITH LOW LEVEL
RETURN FLOW REESTABLISHED ACROSS THE CENTRAL PLAINS BY SUNRISE
SATURDAY. THIS LOW LEVEL RETURN FLOW WILL PROMOTE WEAK LOW LEVEL
WAA WITHIN A SOUTH/SOUTHEASTERLY LOW LEVEL WIND FIELD. ~25 DEGREE
RISES ARE EXPECTED FOR THE MOST PART SATURDAY...WHICH YIELDS
SATURDAY AFTERNOON HIGHS IN THE UPPER 20S TO UPPER 30S ACROSS THE
CWA.
LONG TERM...00Z SUNDAY THROUGH FRIDAY. THE START OF THE LONG TERM
PERIOD WILL FEATURE AN H5 RIDGE ACROSS THE CENTRAL UNITED STATES
WITH A LARGE TROUGH IN THE WEST. THERE IS GENERAL CONSENSUS THAT
THE WESTERN U.S. TROUGH WILL MOVE ACROSS THE CENTRAL PLAINS LATE
SATURDAY NIGHT INTO SUNDAY...HOWEVER FINDING AGREEMENT IN THE
DETAILS REMAINS ELUSIVE. DIFFERENCES REMAIN AMONGST THE VARIOUS
MODEL SOLUTIONS IN THE OVERALL STRENGTH/TIMING WHICH OBVIOUSLY HAVE
LARGE IMPACTS IN REGARDS TO POPS AND PRECIPITATION TYPE. AT THIS
POINT...HAVE CONTINUED TO CARRY A BLENDED MODEL SOLUTION WHICH GIVES
POPS GENERALLY IN THE 30 PERCENT RANGE ON SUNDAY. THIS ALSO LINGERS
A POP IN THE FAR EAST FOR SUNDAY EVENING WHICH ACCOUNTS FOR SOME OF
THE SLOWER MODEL SOLUTIONS...IN PARTICULAR THE ECMWF.
TEMPERATURES AND THE OVERALL THERMAL PROFILE REMAINS UNCERTAIN
THOUGH THE GENERAL TREND SEEMS TO KEEP WARMER H85 TEMPERATURES IN
THE MORNING...FOLLOWED BY COLDER AIR ARRIVING BEHIND A COLD FRONT IN
THE AFTERNOON. IF PRECIPITATION STARTS EARLY ENOUGH ON
SUNDAY...COULD SEE SOME POTENTIAL FOR LIGHT FREEZING RAIN DUE TO THE
EXPECTED BELOW FREEZING SURFACE TEMPERATURES...BUT WITH CONFIDENCE
STILL SO LOW IN THE DETAILS...WILL INSTEAD OPT FOR A RAIN/SNOW MIX.
IN FACT...COULD SEE SOME JUSTIFICATION FOR A RAIN/SNOW MIX MUCH OF
THE DAY DEPENDING ON THE TIMING OF THE COLDER AIR ALOFT. IN REGARDS
TO SUNDAY EVENING...WILL GO WITH SNOW SINCE MOST SOLUTIONS HAVE THE
COLD AIR IN PLACE BY THAT TIME.
ANOTHER CONCERN ON SUNDAY WILL BE STRONG WINDS BEHIND THE COLD
FRONT. STRONG PRESSURE RISES ARE SHOWN ACROSS THE FORECAST AREA.
MOMENTUM TRANSFER FROM NAM BUFR SOUNDINGS SUGGEST GUSTS COULD
APPROACH 40 KTS ACROSS MUCH OF THE FORECAST AREA...WITH EVEN
STRONGER WINDS POTENTIALLY TAKING HOLD IN THE SOUTHWEST. CURRENTLY
WE ARE HIGHLIGHTING THE STRONGER WINDS IN THE HAZARDOUS WEATHER
OUTLOOK...AND WILL LET THAT WORDING CONTINUE.
A DRY PERIOD TAKES HOLD AGAIN FOR OVERNIGHT SUNDAY INTO AT LEAST
EARLY TUESDAY AS ANOTHER H5 RIDGE DOMINATES THE CENTRAL PORTION OF
THE COUNTRY. THE NEXT WAVE MOVES THROUGH THE AREA TUESDAY INTO
TUESDAY NIGHT...HOWEVER AGAIN THERE ARE DIFFERENCES IN TIMING
AMONGST THE MODELS. WILL MAINTAIN CONTINUITY FOR NOW AND HOLD ONTO
THE MAIN PRECIPITATION CHANCES TUESDAY NIGHT. PRECIPITATION TYPE
COULD AGAIN BE AN WITH THE GFS COLDER THAN THE ECMWF. HAVE GONE
WITH A RAIN/SNOW COMBINATION IN THE SOUTH...BUT WILL GO ALL SNOW IN
THE NORTH WHERE EVEN THE WARMER ECMWF DROPS H85 TEMPERATURES BELOW
FREEZING TUESDAY EVENING.
THE REMAINDER OF THE FORECAST PERIOD APPEARS TO BE GENERALLY SUPPORT
ABOVE NORMAL TEMPERATURES WITH HIGHS PRIMARILY IN THE 40S. THE
WARMEST DAY COULD TURN OUT TO BE THURSDAY WITH SOME LOCATIONS
POTENTIALLY PUSHING THE 50 DEGREE MARK.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/UPDATE...HEINLEIN
SHORT TERM...BRYANT
LONG TERM...KING
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1038 PM EST SUN JAN 22 2012
.SYNOPSIS...
LOW PRESSURE OVER THE WESTERN GREAT LAKES WILL PUSH A COLD FRONT
INTO THE AREA LATE MONDAY. AHEAD OF THE FRONT...MILDER AIR
WILL ARRIVE AND BRING LIGHT RAIN AND DRIZZLE. SURFACES TONIGHT AND
EARLY MONDAY WILL LIKELY BE BELOW FREEZING SO SOME ICING IS
LIKELY. COOLER AND DRIER AIR WILL COME IN BEHIND THE FRONT MONDAY
NIGHT AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
1030 PM UPDATE...
STILL SEEING SOME VERY LIGHT RETURNS ON RADAR AND THESE CONTINUE
TO BE CONFIRMED AS JUST SNOW FLURRIES PER THE SUSQUEHANNA COUNTY
911 CENTER...AND OBS HERE AT THE NWS OFFICE...SCRANTON...AND MOUNT
POCONO. LOOKING AT RUC MODEL SOUNDINGS...ON FIRST GLANCE IT LOOKS
LIKE A CLASSIC DRIZZLE SOUNDING WITH DRY AIR IN THE MID AND UPPER
LEVELS (NO ICE CRYSTALS). HOWEVER WE HAVE MOISTURE NEAR THE
SURFACE IN THE LOWEST FEW THOUSAND FEET AND WE ARE JUST COLD
ENOUGH (-5C) TO PRODUCE SOME ICE CRYSTALS FOR FLURRIES. AFTER 06Z
WE SHOULD WARM ENOUGH JUST ABOVE THE SURFACE TO CHANGE ANY PRECIP
OVER TO DRIZZLE. WITH SURFACE TEMPS BELOW FREEZING THROUGH
DAYBREAK...AREAS OF FREEZING DRIZZLE IN THE CURRENT FREEZING RAIN
ADVISORY AREA LOOKS ON TRACK. HIGHEST PROBABILITY FOR SOME LIGHT
ICE ACCUMS WILL BE ACROSS THE HIGHER TERRAIN OF NEPA AND THE
WESTERN CATSKILLS. BASED ON LAV GUIDANCE SHOWING KAVP NEAR
FREEZING THROUGH 13Z AND MONTICELLO THROUGH 15Z...EXTENDED THE END
TIME FROM 8 AM TO 11 AM.
ONE LAST THING...OUTSIDE OF THE ADVISORY AREA I STILL THINK THAT
SOME PATCHY FREEZING DRIZZLE IS POSSIBLE ACROSS
CHEMUNG...TIOGA...BROOME...AND SOUTHERN CHENANGO
COUNTIES...ESPECIALLY THE HIGHER UP IN ELEVATION YOU LIVE. CHOSE NOT
TO EXPAND THE ADVISORY BECAUSE THE SOUTHEAST FLOW MAY BE JUST
ENOUGH OF A DOWN SLOPING FACTOR TO LIMIT THE IMPACT OF ANY
FREEZING DRIZZLE. THE OVERNIGHT SHIFT WILL HAVE TO MONITOR THE
RADAR TRENDS JUST TO BE SAFE. THE PREVIOUS AFD IS BELOW...
7 PM UPDATE...AN INTERESTING DEVELOPMENT OVER THE LAST
HOUR OR SO AS THE KBGM RADAR HAS SHOWN SOME VERY LIGHT RETURNS
OVER NORTHERN PA SNEAKING INTO THE SOUTHERN TIER OF NY. THIS IS
CONFIRMED BY WILLIAMSPORT REPORTING VERY LIGHT SNOW AT LAST OB.
OUR HIGHLY SENSITIVE WEB CAM AT THE OFFICE IS SHOWING VERY LIGHT
AND BRIEF PRECIPITATION...BUT WHEN YOU STEP OUTSIDE YOU HAVE TO
STARE AT THE PARKING LOT LIGHTS FOR AT LEAST A MINUTE BEFORE YOU
SEE ANYTHING. WE MAY BE SEEING A FEW FLURRIES ATTM (RUC SOUNDINGS
SHOWING -5C IN THE MOIST LAYER)...BUT IF TRENDS CONTINUE TO
INCREASE AND IT BECOMES MORE APPARENT THAT IT IS FREEING DRIZZLE
THE ADVISORY IN PLACE MAY HAVE TO BE EXPANDED NORTHWEST. FOR NOW
WILL HOLD WITH THE GOING FORECAST AND WILL MONITOR TRENDS TO SEE
IF THIS VERY FINE DRIZZLE OR AREA OF FLURRIES PICKS UP IN
INTENSITY BECAUSE RIGHT NOW IT IS JUST TOO LIGHT TO HAVE AN
IMPACT. THE PREVIOUS AFD IS BELOW...
MARINE LYR HAS SLOWLY BEEN CREEPING NWRD THIS MRNG. ADVANCE
SHD ACCELERATE THIS EVE WITH THE LOSS OF THE SUN AND TIGHTENING OF
THE GRADIENT AHD OF THE LOW. THIS SHALLOW LYR WILL BE THE MOISTURE
SOURCE FOR ANY FREEZING RAIN AND DRIZZLE OVERNIGHT AS MOISTURE AHD
OF THE FNT IS STILL SVRL HRS AWAY. MODELS CONT TO BE VERY LGT WITH
THE OPF...REALLY JUST A FEW HUNDEDTHS AT MOST. CRNT AREA OF THE
ADVISORY DOES SHOW THE BEST AREA HWVE SO WILL LEAVE AS IS EVEN
THOUGH IT LOOKS LIKE ICING WILL BE VERY LGT. TEMPS HAVE REALLY
STRUGGLED TO RISE DESPITE THE HAZY SUN...ALONG WITH DEW PTS STILL
IN THE TEENS AND EVEN SINGLE NUMBERS. THERE/S PTNL FOR THE TEMPS
TO DROP A FEW HRS AFT DARK...ESP OVER THE WRN CATS. NAM CONTS TO
SHOW A GOOD DAMMING SIGNITURE...SO...ANY PCPN THAT DOES FALL WILL
CERTAINLY FREEZE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
FAST MVG OCCLUSION PASSES THRU MON ARND 18Z WITH SHWRS AND GUSTY
WINDS...ALTHOUGH DEEP INV SHD HELP KEEP THE HIGHEST WINDS ABV THE
SFC...SO NO WIND FLAGS NEEDED. CAA DOES NOT REALLY BEGIN UNTIL
LTR MON NGT AND WITH THE MODIFIED AIR...POST FNTL TEMPS STILL ABV
NRML ON TUE. SW FLOW WILL ALSO KEEP ANY WEAK LE CONFINED TO THE
XTRM NORTH...IF AT ALL. SO...MUCH OF THE FCST AREA WILL ENJOY ABV
NRML TEMPS WITH GUSTY WINDS INTO TUE.
UPR TROF AXIS PASSES EARLY WED WHICH WILL BE FLWD BY BRIEF RISING
HGTS AND MILDER AIR ON WED. ANOTHER WEK WV APRCHS LATE IN THE
PD...BUT WITH LTL IF ANY PCPN.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE IN FAIR AGREEMENT WITH MEDIUM RANGE WHICH INCLUDES TWO
NORTHERN STREAM SFC TROFS AND A FAIRLY SIGNIFICANT SOUTHERN
STREAM SYSTEM THAT PASSING TO OUR SOUTH. OVERALL TEMPS WILL RANGE
5 TO 10 DEGREES ABOVE NORMAL AS WE RESIDE IN THE CLIMATOLOGICAL
COLDEST PERIOD OF THE WINTER SEASON.
WEDNESDAY NIGHT WILL BE DRY WITH SFC HIGH PRES IN THE AREA.
ON THURSDAY, SFC LOW PRES IN THE UPPER GREAT LAKES MAY PRODUCE
SOME MIXED WINTRY PRECIP DURING THE MORNING BEFORE TEMPS WARM
ENOUGH FOR JUST PLAIN RAIN. SYSTEM IS NOT VERY STRONG WITH
LIMITED MOISTURE THEREFORE JUST LOW CHC POPS. THURSDAY NIGHT THE
TRAILING COLD FRONT WILL PUSH THROUGH WITH CHC POPS FOR MIXED
RAIN/SNOW SHOWERS CHANGING TO ALL SNOW SHOWERS. ON FRIDAY SOME
LINGERING POST FRONTAL SNOW SHOWERS ARE POSSIBLE DURING THE
MORNING OTHERWISE DRY.
FRIDAY NIGHT THROUGH SATURDAY, A SOUTHERN STREAM LOW PRES SYSTEM
LIFTS FROM THE GULF STATES INTO THE MID ATLANTIC REGION THEN OFF
THE COAST. THE ECMWF BRINGS THIS FEATURE FURTHER NORTH SPREADING
PRECIP ACROSS THE ENTIRE CWA WHILE THE GFS IS MUCH FURTHER SOUTH
WITH NO IMPACT HERE. WILL FOLLOW HPC GUIDANCE WHICH HAS CHC POPS
NE PA FRIDAY NIGHT THEN CHC POPS ENTIRE FA ON SATURDAY. FOR NOW
THE COLUMN LOOKS COLD ENOUGH FOR PRIMARILY ALL SNOW, BUT THERE
COULD BE A RAIN/SNOW MIX SATURDAY MIDDAY OVER FAR SOUTHERN FA.
BEHIND THIS SYSTEM A NORTHERN STREAM SFC TROF WILL PASS THROUGH
THE REGION SATURDAY NIGHT WITH CHC POPS FOR SNOW SHOWERS. ON
SUNDAY A COLDER AIRMASS ALONG WITH WESTERLY FLOW WILL CONTINUE CHC
POPS FOR SNOW SHOWERS ESPECIALLY NRN CWA.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
MVFR CIGS IMPACTING ALL TERMINALS OUTSIDE OF KSYR NOW AND THIS
WILL CONTINUE OVERNIGHT. AT KSYR...A STRONG SOUTHEAST WIND MAY BE
JUST ENOUGH TO DOWN SLOPE OFF THE HILLS SOUTH OF THE AIRPORT TO
KEEP CIGS AT VFR THROUGH DAYBREAK. MOST TERMINALS REMAIN DRY
TONIGHT BUT SOME FREEZING DRIZZLE IS STILL POSSIBLE AT KAVP AND
KBGM AS A MOIST SOUTHEAST FLOW CONTINUES. BEST CHANCE FOR THIS TO
OCCUR WILL BETWEEN 05Z AND 07Z AT KAVP AND AFTER 07Z AT KBGM.
CONFIDENCE ON THE EXACT TIMING IS A BIT LOWER THAN AVERAGE THIS
CLOSE TO ARRIVAL TIME BECAUSE WE HAVE BEGUN TO SEE SOME LIGHT RETURNS
IN NEPA. WILL MONITOR AND ADJUST WITH AMENDMENTS AS NEEDED.
EVENTUALLY TEMPS WILL WARM UP ENOUGH BY DAYBREAK THAT IS WE ARE
STILL SEEING SOME MIST OR DRIZZLE...IT WILL NOT BE FREEZING. ON
MONDAY MVFR VSBYS WILL DEVELOP AFTER 17Z ALL TERMINALS IN LIGHT
RAIN.
OUTSIDE OF THE VALLEY TERMINALS (KELM/KAVP)...SOUTHEAST WINDS
WILL BE GUSTY AT 10 TO 15 KTS OVERNIGHT. AT KITH DUE TO THE
SOUTHERLY COMPONENT OF THE WIND...SOME GUSTS MAY APPROACH 20-25
KTS TOWARD DAYBREAK. WITH A STRONG LLJ IN PLACE...ESPECIALLY
ACROSS THE FINGER LAKES...WILL ADD LLWS TO ALL TERMINALS OUTSIDE
OF KRME AND KAVP TONIGHT FOR WINDS BETWEEN 40 AND 45 KTS AT AROUND
2000 FEET OUT OF THE SOUTH. SOUTHEAST WINDS INCREASE ON
MONDAY...ESPECIALLY PRIOR TO THE ARRIVAL OF RAIN...WITH GUSTS
BETWEEN 20 AND 30 KTS...ESPECIALLY NY TERMINALS OUTSIDE OF KELM
WILL CONTINUE LLWS IN THE TAFS FOR THE SAME LOCATIONS AS THE LLJ
ACTUALLY INCREASES.
.OUTLOOK...
MON NGT/TUE/WED...PATCHY MVFR CNTRL NY...MAINLY VFR NE PA.
THU/FRI...MVFR IN RAIN/SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZING RAIN ADVISORY UNTIL 11 AM EST MONDAY FOR PAZ038>040-
043-044-047-048-072.
NY...FREEZING RAIN ADVISORY UNTIL 11 AM EST MONDAY FOR NYZ057-062.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/HEDEN
SHORT TERM...DGM
LONG TERM...RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
645 PM EST SUN JAN 22 2012
.SYNOPSIS...
COOL AND MOIST CONDITIONS WILL PREVAIL FOR THE REMAINDER OF TODAY
AS HIGH PRESSURE WEDGES IN FROM THE NORTH. A WARM FRONT WILL LIFT
NORTH ACROSS THE REGION MONDAY. A COLD FRONT IS EXPECTED TO CROSS
THE AREA MONDAY NIGHT INTO TUESDAY. HIGH PRESSURE WILL FOLLOW FROM
LATE TUESDAY THROUGH MID WEEK. ANOTHER FRONT WILL APPROACH FROM
THE NORTH EARLY ON FRIDAY WHILE A MORE POTENT LOW PRESSURE SYSTEM
MOVES IN FROM THE GULF COAST FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM SUNDAY...INCREASING PARTIAL THICKNESSES...IE.
1000MB-850MB...INDICATE WARM AIR ADVECTING ALOFT. THE COLD AIR
REMAINS JUST DEEP ENOUGH TO REMAIN WEDGED ACROSS THE CAROLINAS. AS
MENTIONED PRIOR...THE OUTER PERIMETER OF THE WEDGE IS SLOWLY
DECAYING INWARD. THE 925MB PROGS INDICATE WINDS TO VEER TO THE SOUTH
OVERNIGHT...BUT NOT QUITE MIXING TO THE SFC. THE STALLED BOUNDARY
SOUTH OF THE AREA WILL MAKE SOME NORTHWARD PROGRESS...CROSSING MUCH
OF THE AREA BY 07Z. OVERNIGHT TEMPS WILL EITHER HOLD STEADY OR
INDICATE A SLOW RISE. THEREFORE...TONIGHTS MINS LIKELY TO OCCUR
DURING A PORTION OF THIS EVENING.
PREVIOUS DISCUSSION..............................................
AS OF 2:30 PM SUNDAY...HIGH PRESSURE WEDGE WHICH HAS BEEN ENTRENCHED
ACROSS THE AREA TODAY IS SLOWLY BEGINNING TO ERODE BACK TO THE
NORTH. THIS IS EVIDENT BOTH BY LATEST MSAS SURFACE ANALYSIS...AND
SUBTLE RISING OF CLOUD HEIGHTS ACROSS THE AREA. RUC/NAM FORECAST
PRESSURE TENDENCIES SHOW DECREASING PRESSURES DURING THE REST OF
TODAY AND TONIGHT...SO EXPECT WEDGE WILL CONTINUE TO RETREAT. AT THE
SAME TIME...LOW PRESSURE OVER THE MISSOURI VALLEY WILL PUSH A WARM
FRONT TOWARDS US OVERNIGHT. THIS WILL HELP TO FURTHER ERODE THE
WEDGE AS WINDS SLOWLY TURN TO THE E/SE...CREATING SOME ENHANCED
LOW-LEVEL ISENTROPIC LIFT. WHILE THIS OCCURS FRONTAL INVERSION WILL
LOWER...FORCING TRAPPED MOISTURE CLOSER TO THE GROUND. FOR THIS
REASON HAVE CONTINUED PATCHY DRIZZLE...AND ADDED PATCHY FOG SIMPLY
DUE TO LOWERING OF COLUMN MOISTURE.
ALTHOUGH WARM FRONT WILL REMAIN SOUTH AND WEST OF THE AREA...THE
TEMPERATURES WILL BEGIN TO WARM OVERNIGHT. VERY ATYPICAL TEMPERATURE
CURVE EXPECTED THROUGH THE REST OF THE DAY. TEMPS MAY WARM ANOTHER
DEGREE OR TWO THIS EVE AS WEDGE ERODES...BEFORE COOLING DIURNALLY
AFTER SUNSET. HOWEVER...AS WAA BEGINS ALOFT AND SURFACE WINDS TURN
MORE E/SE...TEMPS WILL BEGIN TO RISE AFTER MIDNIGHT. MAX-TO-MIN
RANGES WILL BE ONLY A FEW DEGREES...DROPPING TO AROUND 40 WELL
INLAND AND THE LOW 40S NEAR THE COAST...BEFORE RISING A FEW DEGREES
BEFORE DAWN.
TOWARD MONDAY MORNING SOME MORE SUBSTANTIAL RAIN...MEANING
MEASURABLE...WILL APPROACH THE WESTERN ZONES WITH THE WARM FRONT.
SREF 3-HR PROBS DON`T EVEN REACH 50% BY 12Z...BUT HAVE ADDED SCHC
FOR SHOWERS FOR THE PEE DEE OF SC AND ROBESON COUNTY...WITH LOW END
CHANCE IN DARLINGTON/MARLBORO COUNTIES AT THE VERY END OF THE
PERIOD.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 2:30 PM SUNDAY...REMNANTS OF SURFACE WEDGE NOW IN PLACE WILL
BE IN THE PROCESS OF COMPLETELY ERODING AT THE BEGINNING OF THE
PERIOD AS A WARM FRONT LIFTS NORTH ACROSS THE AREA AND A COLD
FRONT APPROACHES FROM THE WEST. FRONT WILL MOVE ACROSS THE CWA AND
OFFSHORE ON TUESDAY MORNING...FOLLOWED BY A MILDLY COOLER AIRMASS
AS HIGH PRESSURE BUILDS IN FROM THE WEST ON TUESDAY NIGHT.
MONDAY WILL START OFF OVERCAST AND COOL BEFORE CAD PATTERN BREAKS
DOWN COMPLETELY. NOT TOO BULLISH ON WEATHER ASSOCIATED WITH NEXT
FROPA. ALTHOUGH THERE WILL BE ADEQUATE MOISTURE WITH P/W VALUES IN
THE 1 INCH-PLUS RANGE AND A MOIST BOUNDARY LAYER...FORCING AND
INSTABILITY WILL BE ON THE MODEST SIDE. BEST UPPER SUPPORT WILL
PASS WELL TO THE NORTH AND WEST OF THE AREA AS A SUBSTANTIAL SHORT
WAVE TROUGH TRACKS NE WEST OF THE APPALACHIANS. THESE ELEMENTS
WILL STILL WILL SUPPORT MAINLY ISOLATED TO SCATTERED SHOWERS ON
MONDAY AND MONDAY NIGHT. DECREASING MOISTURE AND INCREASING
STABILITY WILL MAKE FOR A DRY TUESDAY. MODEL SOUNDINGS DO SUGGEST
SUBSTANTIAL CLOUD COVER COULD PERSIST INTO TUESDAY THOUGH...WITH
THE GFS IN PARTICULAR SHOWING A THICK DECK OF CIRRUS.
TEMPERATURES WILL BE BACK UP WELL ABOVE NORMAL ON BOTH DAYS...EVEN
ON TUESDAY AS COLD ADVECTION FOLLOWING FROPA WILL BE NEARLY NIL UNTIL
THE OVERNIGHT HOURS. EXPECT UPPER 60S TO AROUND 70 BOTH DAYS. FOR
LOWS LOOKING AT THE 50S MONDAY NIGHT...AND A COOLER LOWER TO MID
40S ON TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 2:30 PM SUNDAY...ALL EYES REMAIN FOCUSED ON THE SOUTHERN
STREAM CUTOFF SYSTEM TO MOVE ACROSS THE AREA LATE IN THE WEEK. THE
FORECAST DILEMMA REMAINS EXACTLY WHEN THIS WILL OCCUR. THE ECMWF
PRODUCTS HAVE SLOWED AND ARE NOW THE MOST INCONSISTENT WHILE THE
GFS AND OTHER MEDIUM RANGE MODELS ARE MORE CONSISTENT. HPC FAVORS
A LATE FRIDAY INTO EARLY SATURDAY SOLUTION WHEN THE MID LEVEL
FEATURE OPENS UP MOVING ACROSS THE WESTERN CAROLINAS. HAVE
ADJUSTED POPS ACCORDINGLY WITH THE HIGHEST VALUES NOW BETWEEN 0000
AND 1200 UTC SATURDAY. FOCUS ON TEMPERATURES SHIFTS TO THE NEW DAY
SUNDAY IN THE WAKE OF THE SYSTEM WITH A CONSIDERABLE SHIFT BACK
TOWARD CLIMATOLOGY. FOR THE PREVIOUS DAYS...STILL ABOVE
CLIMATOLOGY FOR THE MOST PART.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...HIGH CONFIDENCE FOR IFR CONDITIONS AT ALL TERMINALS AS
WEDGE REMAINS FIRMLY IN PLACE. WITH SOME WARM AIR ADVECTION ALOFT
TOWARD MORNING...EXPECT VISIBILITIES TO LOWER TO IFR OR LOWER...WITH
POSSIBLE DRIZZLE. MONDAY...WARM AIR WILL CONTINUE TO OVERRIDE THE
COLD DOME AT THE SURFACE...WITH CONTINUED IFR CONDITIONS. A SPRINKLE
IS POSSIBLE WITH A WEAK DISTURBANCE...BUT SHOULD BE ISOLATED IN
NATURE. COLD AIR WILL FINALLY RETREAT BY EARLY AFTERNOON...WITH
IMPROVING CONDITIONS. WINDS WILL SHIFT TO THE SOUTHEAST AS THE WARM
FRONT WAVES NORTH ACROSS THE REGION.
EXTENDED OUTLOOK...VFR TO DEVELOP MONDAY LATE WITH A SLIGHT CHANCE
OF SHOWERS AS A WARM FRONT WORKS NORTH. LOW CONFIDENCE FOR MORNING
FOG WEDNESDAY AND THURSDAY MORNINGS. CHANCE OF SHOWERS/TEMPO IFR
FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM SUNDAY...WINDS ACROSS THE COOLER SHELF AND COASTAL ILM
WATERS WILL LIMIT ANY HIER WIND SPEEDS ALOFT FROM MIXING DOWN TO THE
OCEAN SFC. HRRR AS WELL AS THE NAM INDICATE OCEAN WINDS WINDS TO
SLIGHTLY VEER TO THE ENE ACROSS THE COASTAL WATERS THROUGH DAYBREAK
MON. THIS A RESULT OF SFC RIDGING OR NOSING DOWN FROM THE NEW
ENGLAND STATES AND ACROSS THE CENTRAL CAROLINAS. THE STALLED
BOUNDARY IN THE VICINITY OF THE MOUTH OF THE SAVANNAH RIVER...TO
RETURN NORTHWARD AS A WARM FRONT OVERNIGHT AND SHOULD BE WITHIN THE
ILM NEIGHBORHOOD BY DAYBREAK. WINDS AND SEAS OVERNIGHT WILL REMAIN
BELOW SCA OR SCEC THRESHOLDS. EXPECT 2 TO 4 FOOT SIG SEAS
OVERNIGHT...AND GENERALLY EXHIBITING 5 TO 7 SECOND PERIODS.
PREVIOUS DISCUSSION.................................................
AS OF 2:30 PM SUNDAY...WEDGE OF HIGH PRESSURE ACROSS THE
SOUTHEAST IS CONTINUING NE WINDS OVER THE WATERS...ALTHOUGH AT
DECREASING SPEEDS. WINDS OVER THE COASTAL WATERS ARE 10-15 KTS
FROM THE NE...AND THESE WILL FURTHER EASE...AND VEER TO THE
EAST...AS WEDGE BREAKS DOWN TONIGHT. THE DECREASING WINDS WILL
GAIN LESS PURCHASE ON THE WATER...HELPING TO CREATE LOWER
AMPLITUDE WAVE HEIGHTS THROUGH TONIGHT. SEAS OF 3-4 FT EARLY WILL
DROP TO 2-3 FT...BUT A CONFUSED SEA STATE IS EXPECTED DUE TO THE
NE WIND WAVES INTERACTING WITH A RESIDUAL SE SWELL.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 2:30 PM SUNDAY...EASTERLY WIND AT THE BEGINNING OF THE
PERIOD WILL VEER TO THE SW AS A COLD FRONT APPROACHES FROM THE
WEST. COLD FRONT WILL MOVE OFFSHORE TUESDAY MORNING. DO NOT EXPECT
MUCH OF A COLD SURGE FROM THIS FEATURE. HIGH PRESSURE WILL BUILD
IN FROM THE WEST ON TUESDAY AND TUESDAY NIGHT. EXPECT HIGHEST
WINDS WILL BE IN ADVANCE OF THE COLD FRONT...RIGHT AROUND 15 KTS
FROM THE SW MONDAY EVENING AND NIGHT. SEAS WILL PEAK IN THE 3 TO 5
FT RANGE DURING THAT TIME. EXPECT NO FLAGS DURING THE SHORT TERM.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 2:30 PM SUNDAY...NORTHEAST FLOW INITIALLY WILL VEER TO
EASTERLY LATE WEDNESDAY/EARLY THURSDAY AS A SECONDARY SURGE MAKES
A PUSH TOWARD THE AREA. HOWEVER LATEST GUIDANCE SHOWS SOUTHERLY
FLOW TAKING COMMAND EARLY THURSDAY SO WE NO LONGER EXPECT A
NORTHERLY COMPONENT TO THE WINDS AFTER LATE WEDNESDAY. STRONGER
WINDS FIELDS FRIDAY WITH LOW PRESSURE MOVING UP THE COAST.
FORTUNATELY COLD WATER TEMPERATURES WILL KEEP THE STRONGER WINDS
OFF THE SURFACE AT BAY BUT WILL PROBABLY SEE SMALL CRAFT
CONDITIONS VIA SEAS. WAVE SPECTRUM FOR WEDNESDAY AND THURSDAY
SHOULD FEATURE MINIMAL WIND WAVES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RICHARDEK
NEAR TERM...DOUGLASCH/JOSHUADW
SHORT TERM...RICHARDEK
LONG TERM...STEPHENHK
AVIATION...HENRYDL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
310 PM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM SATURDAY...POTENT SHORTWAVE CLEARLY EVIDENT ON WV
IMAGERY PUSHING ACROSS NORTH GEORGIA ATTM WILL PIVOT THROUGH THE
AREA TONIGHT. ADDITIONALLY...COLD FRONT MOVING EAST THROUGH UPSTATE
SC WILL BECOME MORE E-W ORIENTED AND DROP SOUTHWARD OVERNIGHT. THESE
TWO WILL WORK TOGETHER TO CONTINUE THUNDERSTORMS THROUGH TONIGHT.
LATEST REGIONAL MOSAIC SHOWS A LINE OF STRONGER THUNDERSTORMS FROM
APPROXIMATELY COLUMBIA, SC SOUTHWEST TO MACON, GA. THE STRONGEST
STORMS ARE COLLOCATED WITH ENHANCED LIFT FROM THE PUNCH OF THE S/W
TROUGH...AND EXPECT THE DEEPEST CONVECTION WILL PERSIST IN THIS
MANNER. ALTHOUGH THE SHORTWAVE IS PROGGED TO WEAKEN AS IT MOVES
NORTHEAST TONIGHT...IT APPEARS TO BE SLIGHTLY STRONGER THAN GUIDANCE
HAD SUGGESTED WHICH MAY PERMIT CONVECTION TO CONTINUE LONGER. LATEST
RUC AND HRRR ENSEMBLE REFLECTIVITY HAVE A GOOD HANDLE ON ONGOING
SITUATION...SO HAVE USED A BLEND OF THESE FOR TIMING OF CONVECTION.
VERY LITTLE INSTABILITY...LI`S GREATER THAN 0...AND WINDS ON THE LTX
VWP OF ONLY 30 KTS AT 2 KFT ALL PROMOTE THE CONTINUED IDEA OF ONLY
LIMITED SEVERE POTENTIAL DURING THE NEXT SEVERAL HOURS...EVEN THOUGH
THE SOUTHERN HALF OF THE CWA REMAINS IN A SLIGHT RISK.
STILL...FORECAST GUIDANCE DEVELOPS SOME 7 C/KM ML LAPSE RATES...LI`S
TO -2...AND 0-6 KM SHEAR SUPPORTIVE OF MULTICELL STRUCTURES. HAVE
KEPT SCT TSTMS IN WX GRIDS WITH CATEGORICAL POP FROM WEST TO EAST
THROUGH 10 PM. CANNOT RULE OUT ONE OR TWO WARNINGS TONIGHT...BUT
EXPECT PRIMARILY SUB-SEVERE WIND AND ISOLATED SMALL HAIL.
FROPA OCCURS OVERNIGHT...AND HAVE ADJUSTED MIN TEMPS DOWNWARD A FEW
DEGREES TO ACCOUNT FOR SLIGHTLY FASTER PROGRESSION. WINDS WILL TURN
TO THE NORTH AT LBT BY 10PM...WILMINGTON AROUND MIDNIGHT...AND
GEORGETOWN BY MORNING. VERY LITTLE DRYING BEHIND THE FRONT DUE TO
MOISTURE BECOMING TRAPPED BENEATH THE FRONTAL INVERSION...SO VERY
LIGHT RAIN SHOWERS AND DRIZZLE WILL PERSIST THROUGH MORNING. MINS
TONIGHT WILL RANGE FROM THE LOWER 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE FAR SOUTH.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 2:30 PM SATURDAY...COOL...CLOUDY AND MOIST DAY IN STORE FOR
SUNDAY AS A SHORT-LIVED COLD AIR DAMMING SITUATION SETS UP. STEADY
NE FLOW AT THE SURFACE AND EXTENSIVE CLOUD COVER WILL KEEP
AFTERNOON TEMPERATURES A DEGREE OR SO EITHER SIDE OF 50 MOST
LOCATIONS. AS IS TYPICAL FOR THIS TYPE OF PATTERN...EXPECT PATCHY
DRIZZLE OR LIGHT RAIN TO MAKE APPEARANCES AT TIMES...WITH MINIMAL
QPF DUE TO WEAK FORCING AND SHALLOW NATURE OF MOISTURE. THERE WILL
BE A LIMITED DIURNAL RANGE OF TEMPERATURES...WITH LOWS MAINLY IN
THE 40S OVERNIGHT.
WEDGE PATTERN WILL ERODE EARLY ON MONDAY AS A COLD FRONT AND
ASSOCIATED UPPER TROUGH APPROACH FROM THE WEST. FLOW WILL TURN TO
THE SOUTH AND THEN SW MONDAY AFTERNOON...ALLOWING FOR A BIG WARM
UP FROM THE PREVIOUS DAY. EXPECT HIGHS IN THE UPPER 60S TO AROUND
70...ABOUT 20 DEGREES HIGHER THAN ON SUNDAY. FRONT WILL MOVE
ACROSS THE EASTERN CAROLINAS MONDAY EVENING AND OVERNIGHT AND WILL
BE OFFSHORE BY AROUND DAYBREAK ON TUESDAY. MOISTURE WILL BE
LIMITED WITH THIS SYSTEM AND BEST UPPER SUPPORT WILL PASS WELL TO
THE NORTH...SO EXPECT ONLY ISOLATED TO SCATTERED CONVECTION TO
ACCOMPANY FROPA. NOT MUCH IN THE WAY OF COLD ADVECTION WITH THIS
FRONT...SO EXPECT LOWS WILL RANGE FROM THE MID 40S INLAND TO
AROUND 50 AT THE COAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 2:30 PM SATURDAY...MAIN FEATURE FOR THE EXTENDED CONTINUES
TO BE THE CUTOFF MEANDERING ABOUT THE SOUTHWEST AND WHEN IT GETS
KICKED OUT. THE LATEST OPERATIONAL RUN OF THE GFS HAS TRENDED MUCH
SLOWER WHILE PREVIOUS RUNS MAINTAINED MORE OF A ZONAL FLOW. HPC
CONTINUES TO FAVOR THE ECMWF SUITE OF PRODUCTS BASED ON MORE
CONSISTENCY. THESE ARE A BIT SLOWER WITH THE SYSTEM BUT OVERALL
ARE SIMILAR TO THIS TIME YESTERDAY. THE ONLY FORECAST CHANGES WITH
THIS PACKAGE WERE TO DELAY THE POPS SLIGHTLY MAINTAINING THE SAME
STRATEGY AS YESTERDAY WITH INCREASING VALUES FROM LATE THURSDAY
THROUGH THE NEW DAY SATURDAY. ONLY MINOR TWEAKS TO TEMPERATURES
WITH A SLIGHT INCREASE ACROSS THE BOARD TO MATCH HPC NUMBERS AND
ADJACENT OFFICES.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SHOWERS HAVE INCREASED MORE RAPIDLY AND ARE ENCOMPASSING
A WIDER AREA THAN EARLIER THOUGHT. BROKEN TO OVERCAST CLOUD VFR
CLOUD COVER WILL PERSIST THROUGH THE AFTERNOON...BUT TEMPO MVFR
VISIBILITIES WILL BE LIKELY WITH THE SHOWERS. SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WITH GUSTS TO 25-28 KNOTS ARE EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING COLD FRONT. HAVE NOT OBSERVED MUCH IN THE
WAY OF SEA FOG...AND CURRENT FORECAST SURFACE WIND
TRAJECTORIES...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN
THE LOW 50S...SUGGEST IF ANY SEA FOG DOES DEVELOP IT WILL BE LIGHT
AND REMAIN EAST OF THE CRE/MYR TERMINALS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME LIKELY LATE THIS
AFTERNOON AT FLO/LBT SPREADING TO THE COASTAL TERMINALS THIS
EVENING. PREDOMINATE MVFR CONDITIONS WILL BECOME LIKELY...WITH
TEMPO IFR IN THE HEAVIEST SHOWERS. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS AND WILL AMEND LATER IF NECESSARY.
HIGH CONFIDENCE IN POST-FRONTAL IFR CEILINGS AND VISIBILITIES MID TO
LATE EVENING...EXCEPT SHORTLY AFTER MIDNIGHT AT MYR/CRE. CONFIDENCE
ID MODERATE THAT FLIGHT CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT
AFTER MIDNIGHT...AND AND SOMEWHAT LOWER CONFIDENCE OF IMPROVED
CONDITIONS AFTER SUNRISE AT THE COASTAL TERMINALS.
EXTENDED OUTLOOK...POTENTIAL FOR IFR/LIFR CONDITIONS RE-DEVELOPING
LATE SUNDAY PERSISTING INTO MONDAY MORNING. ANTICIPATE VFR TO
DEVELOP MONDAY WITH EXPECTED TO CONTINUE THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM SATURDAY...WINDS AND SEAS ARE FINALLY INCREASING SO
SMALL CRAFT ADVISORY WILL CONTINUE THROUGH TONIGHT. SEAS HAVE ONLY
REACHED 6 FT AT FRYING PAN SHOALS SO FAR TODAY...MOSTLY BECAUSE THE
COLD SHELF WATERS HAVE INHIBITED THE STRONGEST WINDS FROM MIXING
DOWN TO THE SURFACE. WINDS HAVE BUMPED TO 20 KTS AT 41110 LAST HOUR
WITH SEAS APPROACHING 5 FT. SWAN AND WNAWAVE BOTH STILL EXPECTING
5-7 FT SEAS ACROSS AMZ250 AND AMZ252...WITH 4-6 FT IN THE SOUTHERN
WATERS. WITH WIND INCREASE...FEEL THIS IS PRUDENT...AND WILL KEEP
SCA AS IS. SMALL CRAFT CONDITIONS WILL IMPROVE RATHER QUICKLY
TONIGHT...BECOMING ONLY AROUND 10 KTS AND VEERING TO THE NORTH THEN
NORTHEAST BY SUNDAY MORNING. CONSEQUENTLY...SEAS FALL TO 3-4
FT...WITH A CONFUSED WAVE SPECTRUM DUE TO CHANGING WINDS.
SCATTERED SHOWERS AND THUNDERSTORMS WILL CROSS THE WATERS LATE
TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 2:30 PM SATURDAY...NELY FLOW OVER THE WATERS ON SUNDAY WILL
TURN SWLY ON MONDAY AS A COLD FRONT APPROACHES FROM THE WEST.
WINDS WILL RANGE FROM 15 TO 20 KTS EARLY ON SUNDAY BEFORE BECOMING
LIGHT AND VEERING TO THE SE OVERNIGHT WITH THE APPROACH OF THE
COLD FRONT. WINDS WILL PICK UP AGAIN MONDAY AFTERNOON BACK IN THE
15 TO 20 KT RANGE FROM THE SW. COLD FRONT MAY MOVE OFFSHORE BY
AROUND DAYBREAK ON TUESDAY. SEAS WILL RANGE FROM 3 TO 5 FT FOR
MUCH OF THE PERIOD.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 2:30 PM SATURDAY...WESTERLY FLOW INITIALLY IN THE WAKE OF THE
COLD FRONT. A SECONDARY PUSH OCCURS LATE TUESDAY INTO WEDNESDAY
WHICH WILL TURN WINDS TO THE NORTHEAST. FINALLY RETURN FLOW SETS UP
THURSDAY AS A SYSTEM TAKES SHAPE WELL TO THE SOUTHWEST. OVERALL WIND
SPEEDS SHOULD REMAIN MODEST WITH THE POSSIBLE EXCEPTION OF LATE INT
HE PERIOD WHEN THE SOUTHWEST FLOW SURGES. SEAS WILL REFLECT THE
MODEST WINDS WITH AROUND TWO FEET FOR TUESDAY AND WEDNESDAY
INCREASING SLIGHTLY THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
AMZ254- 256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...JDW
SHORT TERM...REK
LONG TERM...SHK
AVIATION...MRR
MARINE...REK/JDW/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
238 PM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SATURDAY...MINOR UPDATES TO INCREASE POP ACROSS THE
AREA WHERE RAIN HAS OVERSPREAD MUCH OF THE CWA. HAVE ALSO TRENDED
TEMPS DOWN SEVERAL DEGREES INLAND DUE TO RAIN-COOLING OF THE AIR
MASS. HAVE ADJUSTED THE TEMP CURVE TO ATTEMPT TO ACCOUNT FOR
RAINFALL AS IT HEADS EAST...WITH NO MORE HEATING EXPECTED TODAY.
HAVE NOTICED A SLIGHT SLOWING OF PRECIP IN HRRR...AND WITH LATEST
TORNADO WATCH (TOA 4) STILL 1 TIER OF COUNTIES WEST OF THE ILM
CWA...STILL BELIEVE ONLY A LIMITED SEVERE THREAT WILL EXIST TODAY
ACROSS WESTERN PORTIONS OF THE AREA. OTRW...PREVIOUS DISCUSSION
BELOW:
AS OF 1000 AM SATURDAY...CONCERN TODAY REVOLVES AROUND CONVECTION
POTENTIAL AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
COLD FRONT CURRENTLY ANALYZED TO BE JUST WEST OF THE MTNS AT THIS
TIME IS ADVANCING EAST...WITH A BAND OF PREFRONTAL SHOWERS AND TSTMS
PRECEDING IT. AHEAD OF THIS BOUNDARY...ILM CWA IS FIRMLY ENTRENCHED
IN THE WARM SECTOR WITH DEEP SW FLOW THROUGH THE COLUMN. ALL
LOCATIONS AWAY FROM THE BRUNSWICK COUNTY COAST WERE ALREADY IN THE
60S AS OF 10 AM. MAX TEMPS WILL BE TEMPERED BY SIGNIFICANT CLOUD
COVER...BUT ENOUGH BREAKS WILL ALLOW MOST LOCATIONS TO RISE TO
AROUND 70 TODAY. WITHIN THIS WARM SECTOR...WHERE CLOUDS ARE BREAKING
ACROSS THE UPSTATE OF SC...NUMEROUS SHOWERS ARE DEVELOPING AND
ADVECTING NORTHEAST INTO THIS AREA. HAVE BUMPED POP ACCORDINGLY TO
ACCOUNT FOR THIS.
MAIN IMPACTS STILL EXPECTED TO OCCUR LATE THIS AFTN AND THROUGH
EARLY TONIGHT. SPC CONTINUED THE SLIGHT RISK IN THE SWODY1 FOR
WESTERN PORTIONS...BASICALLY CKI-MAO-MEB AND WEST WITH WIND BEING
THE PRIMARY THREAT. A FEW FACTORS WORKING AGAINST A WIDESPREAD
SEVERE EVENT TODAY HOWEVER...NAMELY LACK OF PARAMETERS WORKING IN
CONCERT. ALTHOUGH SBCAPE WILL JUMP TO 300-500 J/KG OVER INLAND ZONES
(CONTAINED WITHIN THE SLIGHT RISK)...OTHER PARAMETERS APPEAR
LIMITING. 50 KTS AT 2 KFT ON LTX VWP IS ACTUALLY PROGGED TO WEAKEN
SLIGHTLY...SO LLJ WILL ONLY PEAK IN THE 40-50 KT RANGE DURING
CONVECTION. ALTHOUGH 0-6 KM SHEAR VECTOR WILL BE AROUND 40
KTS...FAVORING MULTI-CELLULAR STORM TYPE...AND ML LAPSE RATES
IMPROVE ABOVE 7 C/KM...THESE ARE CONFINED MOSTLY TO EASTERN ZONES.
0-3 KM SRH SHOULD REACH 200-300 M2/S2...PRIMARILY CAUSED BY
INCREASING UNIDIRECTIONAL FLOW WITH HEIGHT...BUT IS ENHANCED IN
AREAS WITH LESSER INSTABILITY. SO...USING THE HRRR ENSEMBLE
REFLECTIVITY AS A GUIDE...EXPECT SHOWERS TO PERSIST THROUGH THE
EARLY AFTN...WITH PREFRONTAL LINE REACHING MARLBORO COUNTY BETWEEN
3P-4P...AND EXITING OFFSHORE AROUND 9P. HAVE REMOVED MENTION OF
GUSTY WINDS FROM WX GRIDS AND EXPECT PRIMARILY A NON SEVERE EVENT.
OF COURSE...CANNOT RULE OUT AN ISOLATED DAMAGING WIND
GUST...ESPECIALLY WITHIN ANY BOWING SEGMENTS/STRUCTURES WITHIN THE
LINE...BUT PRIMARY THREATS WILL BE SUB-SEVERE WIND AND SMALL HAIL.
WILL OF COURSE MONITOR...IF MORE SUNSHINE BREAKS OUT THAN
ANTICIPATED...THIS COULD ENHANCE THE SEVERE THREAT THIS EVE.
COLD FRONT DROPS NORTH TO SOUTH TONIGHT AND SHOULD BE PUSHING
THROUGH THE SOUTHERN PORTIONS OF THE CWA BY 7AM SUNDAY. WEDGING HIGH
PRESSURE BEHIND THIS FRONT TRAPS RESIDUAL MOISTURE ON DECREASING
N/NE WINDS...SO SHOWERS/DRIZZLE WILL PERSIST THROUGH THE NIGHT. MINS
TONIGHT WILL DROP INTO THE MID 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 2:30 PM SATURDAY...COOL...CLOUDY AND MOIST DAY IN STORE FOR
SUNDAY AS A SHORT-LIVED COLD AIR DAMMING SITUATION SETS UP. STEADY
NE FLOW AT THE SURFACE AND EXTENSIVE CLOUD COVER WILL KEEP
AFTERNOON TEMPERATURES A DEGREE OR SO EITHER SIDE OF 50 MOST
LOCATIONS. AS IS TYPICAL FOR THIS TYPE OF PATTERN...EXPECT PATCHY
DRIZZLE OR LIGHT RAIN TO MAKE APPEARANCES AT TIMES...WITH MINIMAL
QPF DUE TO WEAK FORCING AND SHALLOW NATURE OF MOISTURE. THERE WILL
BE A LIMITED DIURNAL RANGE OF TEMPERATURES...WITH LOWS MAINLY IN
THE 40S OVERNIGHT.
WEDGE PATTERN WILL ERODE EARLY ON MONDAY AS A COLD FRONT AND
ASSOCIATED UPPER TROUGH APPROACH FROM THE WEST. FLOW WILL TURN TO
THE SOUTH AND THEN SW MONDAY AFTERNOON...ALLOWING FOR A BIG WARM
UP FROM THE PREVIOUS DAY. EXPECT HIGHS IN THE UPPER 60S TO AROUND
70...ABOUT 20 DEGREES HIGHER THAN ON SUNDAY. FRONT WILL MOVE
ACROSS THE EASTERN CAROLINAS MONDAY EVENING AND OVERNIGHT AND WILL
BE OFFSHORE BY AROUND DAYBREAK ON TUESDAY. MOISTURE WILL BE
LIMITED WITH THIS SYSTEM AND BEST UPPER SUPPORT WILL PASS WELL TO
THE NORTH...SO EXPECT ONLY ISOLATED TO SCATTERED CONVECTION TO
ACCOMPANY FROPA. NOT MUCH IN THE WAY OF COLD ADVECTION WITH THIS
FRONT...SO EXPECT LOWS WILL RANGE FROM THE MID 40S INLAND TO
AROUND 50 AT THE COAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 2:30 PM SATURDAY...MAIN FEATURE FOR THE EXTENDED CONTINUES
TO BE THE CUTOFF MEANDERING ABOUT THE SOUTHWEST AND WHEN IT GETS
KICKED OUT. THE LATEST OPERATIONAL RUN OF THE GFS HAS TRENDED MUCH
SLOWER WHILE PREVIOUS RUNS MAINTAINED MORE OF A ZONAL FLOW. HPC
CONTINUES TO FAVOR THE ECMWF SUITE OF PRODUCTS BASED ON MORE
CONSISTENCY. THESE ARE A BIT SLOWER WITH THE SYSTEM BUT OVERALL
ARE SIMILAR TO THIS TIME YESTERDAY. THE ONLY FORECAST CHANGES WITH
THIS PACKAGE WERE TO DELAY THE POPS SLIGHTLY MAINTAINING THE SAME
STRATEGY AS YESTERDAY WITH INCREASING VALUES FROM LATE THURSDAY
THROUGH THE NEW DAY SATURDAY. ONLY MINOR TWEAKS TO TEMPERATURES
WITH A SLIGHT INCREASE ACROSS THE BOARD TO MATCH HPC NUMBERS AND
ADJACENT OFFICES.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SHOWERS HAVE INCREASED MORE RAPIDLY AND ARE ENCOMPASSING
A WIDER AREA THAN EARLIER THOUGHT. BROKEN TO OVERCAST CLOUD VFR
CLOUD COVER WILL PERSIST THROUGH THE AFTERNOON...BUT TEMPO MVFR
VISIBILITIES WILL BE LIKELY WITH THE SHOWERS. SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WITH GUSTS TO 25-28 KNOTS ARE EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING COLD FRONT. HAVE NOT OBSERVED MUCH IN THE
WAY OF SEA FOG...AND CURRENT FORECAST SURFACE WIND
TRAJECTORIES...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN
THE LOW 50S...SUGGEST IF ANY SEA FOG DOES DEVELOP IT WILL BE LIGHT
AND REMAIN EAST OF THE CRE/MYR TERMINALS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME LIKELY LATE THIS
AFTERNOON AT FLO/LBT SPREADING TO THE COASTAL TERMINALS THIS
EVENING. PREDOMINATE MVFR CONDITIONS WILL BECOME LIKELY...WITH
TEMPO IFR IN THE HEAVIEST SHOWERS. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS AND WILL AMEND LATER IF NECESSARY.
HIGH CONFIDENCE IN POST-FRONTAL IFR CEILINGS AND VISIBILITIES MID TO
LATE EVENING...EXCEPT SHORTLY AFTER MIDNIGHT AT MYR/CRE. CONFIDENCE
ID MODERATE THAT FLIGHT CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT
AFTER MIDNIGHT...AND AND SOMEWHAT LOWER CONFIDENCE OF IMPROVED
CONDITIONS AFTER SUNRISE AT THE COASTAL TERMINALS.
EXTENDED OUTLOOK...POTENTIAL FOR IFR/LIFR CONDITIONS RE-DEVELOPING
LATE SUNDAY PERSISTING INTO MONDAY MORNING. ANTICIPATE VFR TO
DEVELOP MONDAY WITH EXPECTED TO CONTINUE THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SATURDAY...NO MAJOR CHANGES FOR THIS UPDATE. SEAS HAVE
BEGUN TO INCREASE ACROSS THE SHELF WATERS WITH 41110 REPORTING 4.6
FT AT 12 PM. LATEST SWAN RUN KEEPS SCA SEAS BEYOND 00Z SO WILL
CONSIDER EXTENDING SCA WITH THE 3PM PACKAGE. PREVIOUS DISCUSSION
BELOW:
AS OF 1000 AM SATURDAY...SMALL CRAFT ADVISORY IN EFFECT FOR ALL
WATERS THROUGH TONIGHT. FORECAST REMAINS ON TRACK FOR SEA
HEIGHTS...WITH 41013 REPORTING 7 FT AT 10 AM...WITH 4 FT AT 41110.
WINDS HAVE BECOME QUITE GUSTY AT FRYING PAN SHOALS...BUT COLD SHELF
WATERS ARE KEEPING WIND GUSTS DOWN IN THE INNER 20 NM. EXPECT GUSTS
TO SLOWLY INCREASE...ESPECIALLY ACROSS AMZ250 AND AMZ252...HELPING
TO FORCE WIND DRIVEN WAVES UP TO 6 FT BEFORE EASING TONIGHT. A FEW
WAVES NEAR THE OUTER 20 NM RANGE WILL REACH 8 FT LATE THIS AFTN. SW
WINDS OF 15-25 KTS WILL PERSIST THROUGH THE FRONTAL PASSAGE
TONIGHT...WHEN THEY WILL TURN TO THE NORTH AND DECREASE TO LESS THAN
15 KTS. SEAS WILL FALL IN TANDEM...BECOMING 3-4 FT WITH A NORTHERLY
CHOP BY THE END OF THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE WATERS
LATE TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 2:30 PM SATURDAY...NELY FLOW OVER THE WATERS ON SUNDAY WILL
TURN SWLY ON MONDAY AS A COLD FRONT APPROACHES FROM THE WEST.
WINDS WILL RANGE FROM 15 TO 20 KTS EARLY ON SUNDAY BEFORE BECOMING
LIGHT AND VEERING TO THE SE OVERNIGHT WITH THE APPROACH OF THE
COLD FRONT. WINDS WILL PICK UP AGAIN MONDAY AFTERNOON BACK IN THE
15 TO 20 KT RANGE FROM THE SW. COLD FRONT MAY MOVE OFFSHORE BY
AROUND DAYBREAK ON TUESDAY. SEAS WILL RANGE FROM 3 TO 5 FT FOR
MUCH OF THE PERIOD.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 2:30 PM SATURDAY...WESTERLY FLOW INITIALLY IN THE WAKE OF THE COLD
FRONT. A SECONDARY PUSH OCCURS LATE TUESDAY INTO WEDNESDAY WHICH
WILL TURN WINDS TO THE NORTHEAST. FINALLY RETURN FLOW SETS UP
THURSDAY AS A SYSTEM TAKES SHAPE WELL TO THE SOUTHWEST. OVERALL WIND
SPEEDS SHOULD REMAIN MODEST WITH THE POSSIBLE EXCEPTION OF LATE INT
HE PERIOD WHEN THE SOUTHWEST FLOW SURGES. SEAS WILL REFLECT THE
MODEST WINDS WITH AROUND TWO FEET FOR TUESDAY AND WEDNESDAY
INCREASING SLIGHTLY THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR AMZ254-
256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...JDW
SHORT TERM...REK
LONG TERM...SHK
AVIATION...MRR
MARINE...REK/JDW/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1250 PM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SATURDAY...MINOR UPDATES TO INCREASE POP ACROSS THE
AREA WHERE RAIN HAS OVERSPREAD MUCH OF THE CWA. HAVE ALSO TRENDED
TEMPS DOWN SEVERAL DEGREES INLAND DUE TO RAIN-COOLING OF THE AIR
MASS. HAVE ADJUSTED THE TEMP CURVE TO ATTEMPT TO ACCOUNT FOR
RAINFALL AS IT HEADS EAST...WITH NO MORE HEATING EXPECTED TODAY.
HAVE NOTICED A SLIGHT SLOWING OF PRECIP IN HRRR...AND WITH LATEST
TORNADO WATCH (TOA 4) STILL 1 TIER OF COUNTIES WEST OF THE ILM
CWA...STILL BELIEVE ONLY A LIMITED SEVERE THREAT WILL EXIST TODAY
ACROSS WESTERN PORTIONS OF THE AREA. OTRW...PREVIOUS DISCUSSION
BELOW:
AS OF 1000 AM SATURDAY...CONCERN TODAY REVOLVES AROUND CONVECTION
POTENTIAL AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
COLD FRONT CURRENTLY ANALYZED TO BE JUST WEST OF THE MTNS AT THIS
TIME IS ADVANCING EAST...WITH A BAND OF PREFRONTAL SHOWERS AND TSTMS
PRECEDING IT. AHEAD OF THIS BOUNDARY...ILM CWA IS FIRMLY ENTRENCHED
IN THE WARM SECTOR WITH DEEP SW FLOW THROUGH THE COLUMN. ALL
LOCATIONS AWAY FROM THE BRUNSWICK COUNTY COAST WERE ALREADY IN THE
60S AS OF 10 AM. MAX TEMPS WILL BE TEMPERED BY SIGNIFICANT CLOUD
COVER...BUT ENOUGH BREAKS WILL ALLOW MOST LOCATIONS TO RISE TO
AROUND 70 TODAY. WITHIN THIS WARM SECTOR...WHERE CLOUDS ARE BREAKING
ACROSS THE UPSTATE OF SC...NUMEROUS SHOWERS ARE DEVELOPING AND
ADVECTING NORTHEAST INTO THIS AREA. HAVE BUMPED POP ACCORDINGLY TO
ACCOUNT FOR THIS.
MAIN IMPACTS STILL EXPECTED TO OCCUR LATE THIS AFTN AND THROUGH
EARLY TONIGHT. SPC CONTINUED THE SLIGHT RISK IN THE SWODY1 FOR
WESTERN PORTIONS...BASICALLY CKI-MAO-MEB AND WEST WITH WIND BEING
THE PRIMARY THREAT. A FEW FACTORS WORKING AGAINST A WIDESPREAD
SEVERE EVENT TODAY HOWEVER...NAMELY LACK OF PARAMETERS WORKING IN
CONCERT. ALTHOUGH SBCAPE WILL JUMP TO 300-500 J/KG OVER INLAND ZONES
(CONTAINED WITHIN THE SLIGHT RISK)...OTHER PARAMETERS APPEAR
LIMITING. 50 KTS AT 2 KFT ON LTX VWP IS ACTUALLY PROGGED TO WEAKEN
SLIGHTLY...SO LLJ WILL ONLY PEAK IN THE 40-50 KT RANGE DURING
CONVECTION. ALTHOUGH 0-6 KM SHEAR VECTOR WILL BE AROUND 40
KTS...FAVORING MULTI-CELLULAR STORM TYPE...AND ML LAPSE RATES
IMPROVE ABOVE 7 C/KM...THESE ARE CONFINED MOSTLY TO EASTERN ZONES.
0-3 KM SRH SHOULD REACH 200-300 M2/S2...PRIMARILY CAUSED BY
INCREASING UNIDIRECTIONAL FLOW WITH HEIGHT...BUT IS ENHANCED IN
AREAS WITH LESSER INSTABILITY. SO...USING THE HRRR ENSEMBLE
REFLECTIVITY AS A GUIDE...EXPECT SHOWERS TO PERSIST THROUGH THE
EARLY AFTN...WITH PREFRONTAL LINE REACHING MARLBORO COUNTY BETWEEN
3P-4P...AND EXITING OFFSHORE AROUND 9P. HAVE REMOVED MENTION OF
GUSTY WINDS FROM WX GRIDS AND EXPECT PRIMARILY A NON SEVERE EVENT.
OF COURSE...CANNOT RULE OUT AN ISOLATED DAMAGING WIND
GUST...ESPECIALLY WITHIN ANY BOWING SEGMENTS/STRUCTURES WITHIN THE
LINE...BUT PRIMARY THREATS WILL BE SUB-SEVERE WIND AND SMALL HAIL.
WILL OF COURSE MONITOR...IF MORE SUNSHINE BREAKS OUT THAN
ANTICIPATED...THIS COULD ENHANCE THE SEVERE THREAT THIS EVE.
COLD FRONT DROPS NORTH TO SOUTH TONIGHT AND SHOULD BE PUSHING
THROUGH THE SOUTHERN PORTIONS OF THE CWA BY 7AM SUNDAY. WEDGING HIGH
PRESSURE BEHIND THIS FRONT TRAPS RESIDUAL MOISTURE ON DECREASING
N/NE WINDS...SO SHOWERS/DRIZZLE WILL PERSIST THROUGH THE NIGHT. MINS
TONIGHT WILL DROP INTO THE MID 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL RIDGE DOWN INTO THE
CAROLINAS ON SUNDAY FROM HIGH PRESSURE CENTERED OVER NORTHERN
MAINE. LOOKS LIKE COLD AIR WILL WEDGE ITSELF DOWN THE LEE OF THE
APPALACHIANS ON SUNDAY AS LINGERING TROUGH/FRONT WILL REMAIN SOUTH
AND EAST OF LOCAL AREA. THIS SHALLOW COOL AIR WILL WORK ITS WAY IN
WHILE SW FLOW ALOFT WILL ALLOW DRIER AND WARMER LAYER. OVERALL
EXPECT THIS TO PRODUCE LOW CLOUDS AND DRIZZLE/LIGHT RAIN THROUGH
SUNDAY. SHOULD BE AN INTERESTING TEMP FORECAST AS GFS KEEPS COLDER
AIR WEDGED INLAND BUT SHOWS TEMPS CLOSER TO THE UPPER 50S ALONG
THE COAST WHILE NAM SHOWS TEMPS CLOSER TO 50 TO ILM AND COASTAL
AREAS FOR SUNDAY. FOR NOW...LOWERED MAX SLIGHTLY BUT WILL NOT JUMP
TOTALLY ON NAM BANDWAGON JUST YET.
WINDS COME BACK AROUND TO THE SOUTH AT THE SURFACE IN RETURN FLOW
AHEAD OF NEXT SYSTEM APPROACHING ON SUNDAY NIGHT INTO MONDAY. A
DEEPER SOUTHERLY FLOW WILL SET UP WITH A LLJ UP TO 40 KTS PUSHING
MOISTURE BACK INTO AREA. PLENTY OF WAA WILL PRODUCE A RETURN TO
WARMER TEMPS WITH HIGHS REACHING CLOSER TO 70 ON MONDAY. SHOULD
SEE CLOUDS THROUGH THE PERIOD WITH FOG OVERNIGHT. LIGHT PCP ON
SUNDAY WILL TAPER OFF BUT GREATER CHC OF RAIN SHOWERS WILL COME ON
MONDAY AHEAD AND ALONG COLD FRONT. THE FRONT SHOULD MOVE THROUGH
BY LATE MONDAY INTO EARLY TUESDAY. GFS SHOWS PLENTY OF DRY AIR
MOVING IN BY DAYBREAK ON TUESDAY WITH PCP WATER VALUES DROPPING
FROM NEAR 1.3 INCHES DOWN TO LESS THAN A HALF INCH BY TUES
MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...SHOULD SEE A FAIRLY NICE START TO THE
PERIOD WITH DEEP W-NW FLOW AND HIGH PRESSURE BUILDING IN BEHIND
EXITING COLD FRONT. THIS WILL BE RELATIVELY SHORT LIVED AS
PROGRESSIVE FLOW KEEPS THINGS MOVING ALONG. HIGH PRESSURE WILL
SHIFT OFF SHORE AS NEXT SYSTEM MAKES ITS WAY EAST. SHOULD SEE SOME
MID TO HIGH CLOUDS BACK IN THE FORECAST BY WEDNESDAY IN W-SW FLOW
OVER THE TOP OF THE RIDGE ALOFT. WILL SEE SFC HIGH SHIFT OFF SHORE
WITH RETURN FLOW SETTING UP ONCE AGAIN AS COLD FRONT PUSHES IN
FROM THE N-NW. THIS FRONT WILL PRODUCE ANOTHER DAY OF CLOUDS AND
PCP FOR THURS INTO FRI WITH POTENTIAL FOR ANOTHER LOW PRESSURE
SYSTEM MOVING IN FROM THE GULF COAST BY THE WEEKEND.
AS FOR TEMPS...EXPECT TO SEE A GREATER DIURNAL SWING IN A DRIER
AIR MASS INITIALLY. TEMPS WILL BE INTO THE 60S DURING THE DAY BUT
TUES NIGHT AND WED NIGHT WILL HAVE BETTER RADIATIONAL COOLING WITH
LESS IN THE WAY OF CLOUDS AND LOWER DEWPOINTS. THEREFORE OVERNIGHT
LOWS SHOULD MAKE IT DOWN TO 40 OR BELOW. AS CLOUDS AND PCP RETURN
THURS AND FRI TEMPS OVERNIGHT WILL REMAIN HIGHER WITH DAYTIME
HIGHS CONTINUING TO PUSH INTO THE 60S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SHOWERS HAVE INCREASED MORE RAPIDLY AND ARE ENCOMPASSING
A WIDER AREA THAN EARLIER THOUGHT. BROKEN TO OVERCAST CLOUD VFR
CLOUD COVER WILL PERSIST THROUGH THE AFTERNOON...BUT TEMPO MVFR
VISIBILITIES WILL BE LIKELY WITH THE SHOWERS. SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WITH GUSTS TO 25-28 KNOTS ARE EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING COLD FRONT. HAVE NOT OBSERVED MUCH IN THE
WAY OF SEA FOG...AND CURRENT FORECAST SURFACE WIND
TRAJECTORIES...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN
THE LOW 50S...SUGGEST IF ANY SEA FOG DOES DEVELOP IT WILL BE LIGHT
AND REMAIN EAST OF THE CRE/MYR TERMINALS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME LIKELY LATE THIS
AFTERNOON AT FLO/LBT SPREADING TO THE COASTAL TERMINALS THIS
EVENING. PREDOMINATE MVFR CONDITIONS WILL BECOME LIKELY...WITH
TEMPO IFR IN THE HEAVIEST SHOWERS. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS AND WILL AMEND LATER IF NECESSARY.
HIGH CONFIDENCE IN POST-FRONTAL IFR CEILINGS AND VISIBILITIES MID TO
LATE EVENING...EXCEPT SHORTLY AFTER MIDNIGHT AT MYR/CRE. CONFIDENCE
ID MODERATE THAT FLIGHT CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT
AFTER MIDNIGHT...AND AND SOMEWHAT LOWER CONFIDENCE OF IMPROVED
CONDITIONS AFTER SUNRISE AT THE COASTAL TERMINALS.
EXTENDED OUTLOOK...POTENTIAL FOR IFR/LIFR CONDITIONS RE-DEVELOPING
LATE SUNDAY PERSISTING INTO MONDAY MORNING. ANTICIPATE VFR TO
DEVELOP MONDAY WITH EXPECTED TO CONTINUE THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SATURDAY...NO MAJOR CHANGES FOR THIS UPDATE. SEAS HAVE
BEGUN TO INCREASE ACROSS THE SHELF WATERS WITH 41110 REPORTING 4.6
FT AT 12 PM. LATEST SWAN RUN KEEPS SCA SEAS BEYOND 00Z SO WILL
CONSIDER EXTENDING SCA WITH THE 3PM PACKAGE. PREVIOUS DISCUSSION
BELOW:
AS OF 1000 AM SATURDAY...SMALL CRAFT ADVISORY IN EFFECT FOR ALL
WATERS THROUGH TONIGHT. FORECAST REMAINS ON TRACK FOR SEA
HEIGHTS...WITH 41013 REPORTING 7 FT AT 10 AM...WITH 4 FT AT 41110.
WINDS HAVE BECOME QUITE GUSTY AT FRYING PAN SHOALS...BUT COLD SHELF
WATERS ARE KEEPING WIND GUSTS DOWN IN THE INNER 20 NM. EXPECT GUSTS
TO SLOWLY INCREASE...ESPECIALLY ACROSS AMZ250 AND AMZ252...HELPING
TO FORCE WIND DRIVEN WAVES UP TO 6 FT BEFORE EASING TONIGHT. A FEW
WAVES NEAR THE OUTER 20 NM RANGE WILL REACH 8 FT LATE THIS AFTN. SW
WINDS OF 15-25 KTS WILL PERSIST THROUGH THE FRONTAL PASSAGE
TONIGHT...WHEN THEY WILL TURN TO THE NORTH AND DECREASE TO LESS THAN
15 KTS. SEAS WILL FALL IN TANDEM...BECOMING 3-4 FT WITH A NORTHERLY
CHOP BY THE END OF THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE WATERS
LATE TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...COOL BUT LIGHTER NORTHERLY FLOW WILL SET UP
OVER THE COASTAL WATERS ON SUNDAY AS COLD FRONT REMAINS JUST SOUTH
AND EAST. THIS WILL ALLOW SEAS TO RELAX DOWN LESS THAN 4 FT WITH
WINDS 15 KTS OR LESS. AS FLOW CONTINUES TO REMAIN PROGRESSIVE...AN
INCREASING RETURN FLOW WILL SET UP ONCE AGAIN LATE SUN NIGHT INTO
MON WITH WINDS INCREASING UP TO 20 KTS. THIS WILL PUSH SEAS UP
AGAIN INTO THE 3 TO 5 FT RANGE AND MAY SEE A BRIEF PERIOD OF 4 TO
6 FT SEAS BORDERING SCA THRESHOLDS MON AFTERNOON AS COLD FRONT
APPROACHES. EXPECT COLD FRONT TO MOVE THROUGH BY END OF PERIOD
WITH DECREASING OFF SHORE FLOW SETTING UP BY TUES MORNING AND SEAS
DIMINISHING.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...AS MENTIONED PREVIOUSLY THE MARINE COMMUNITY
WILL CONTINUE TO EXPERIENCE CHANGEABLE CONDITIONS IN A PROGRESSIVE
PATTERN. A MUCH LIGHTER FLOW DEVELOPS TUES INTO WED AS HIGH
PRESSURE MOVES OVER THE WATERS WITH WINDS VEERING AROUND FROM NW
TO NE. WITH WINDS REMAINING LESS THAN 10 KTS THROUGH MOST OF THE
PERIOD...SEAS WILL DIMINISH DOWN FROM 2 TO 4 FT TUES MORNING DOWN
TO LESS THAN 3 FT TUES NIGHT THROUGH WED NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
AMZ254- 256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1219 PM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...CONCERN TODAY REVOLVES AROUND CONVECTION
POTENTIAL AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
COLD FRONT CURRENTLY ANALYZED TO BE JUST WEST OF THE MTNS AT THIS
TIME IS ADVANCING EAST...WITH A BAND OF PREFRONTAL SHOWERS AND TSTMS
PRECEDING IT. AHEAD OF THIS BOUNDARY...ILM CWA IS FIRMLY ENTRENCHED
IN THE WARM SECTOR WITH DEEP SW FLOW THROUGH THE COLUMN. ALL
LOCATIONS AWAY FROM THE BRUNSWICK COUNTY COAST WERE ALREADY IN THE
60S AS OF 10 AM. MAX TEMPS WILL BE TEMPERED BY SIGNIFICANT CLOUD
COVER...BUT ENOUGH BREAKS WILL ALLOW MOST LOCATIONS TO RISE TO
AROUND 70 TODAY. WITHIN THIS WARM SECTOR...WHERE CLOUDS ARE BREAKING
ACROSS THE UPSTATE OF SC...NUMEROUS SHOWERS ARE DEVELOPING AND
ADVECTING NORTHEAST INTO THIS AREA. HAVE BUMPED POP ACCORDINGLY TO
ACCOUNT FOR THIS.
MAIN IMPACTS STILL EXPECTED TO OCCUR LATE THIS AFTN AND THROUGH
EARLY TONIGHT. SPC CONTINUED THE SLIGHT RISK IN THE SWODY1 FOR
WESTERN PORTIONS...BASICALLY CKI-MAO-MEB AND WEST WITH WIND BEING
THE PRIMARY THREAT. A FEW FACTORS WORKING AGAINST A WIDESPREAD
SEVERE EVENT TODAY HOWEVER...NAMELY LACK OF PARAMETERS WORKING IN
CONCERT. ALTHOUGH SBCAPE WILL JUMP TO 300-500 J/KG OVER INLAND ZONES
(CONTAINED WITHIN THE SLIGHT RISK)...OTHER PARAMETERS APPEAR
LIMITING. 50 KTS AT 2 KFT ON LTX VWP IS ACTUALLY PROGGED TO WEAKEN
SLIGHTLY...SO LLJ WILL ONLY PEAK IN THE 40-50 KT RANGE DURING
CONVECTION. ALTHOUGH 0-6 KM SHEAR VECTOR WILL BE AROUND 40
KTS...FAVORING MULTI-CELLULAR STORM TYPE...AND ML LAPSE RATES IMPROVE
ABOVE 7 C/KM...THESE ARE CONFINED MOSTLY TO EASTERN ZONES. 0-3 KM
SRH SHOULD REACH 200-300 M2/S2...PRIMARILY CAUSED BY INCREASING
UNIDIRECTIONAL FLOW WITH HEIGHT...BUT IS ENHANCED IN AREAS WITH
LESSER INSTABILITY. SO...USING THE HRRR ENSEMBLE REFLECTIVITY AS A
GUIDE...EXPECT SHOWERS TO PERSIST THROUGH THE EARLY AFTN...WITH
PREFRONTAL LINE REACHING MARLBORO COUNTY BETWEEN 3P-4P...AND EXITING
OFFSHORE AROUND 9P. HAVE REMOVED MENTION OF GUSTY WINDS FROM WX
GRIDS AND EXPECT PRIMARILY A NON SEVERE EVENT. OF COURSE...CANNOT
RULE OUT AN ISOLATED DAMAGING WIND GUST...ESPECIALLY WITHIN ANY
BOWING SEGMENTS/STRUCTURES WITHIN THE LINE...BUT PRIMARY THREATS
WILL BE SUB-SEVERE WIND AND SMALL HAIL. WILL OF COURSE MONITOR...IF
MORE SUNSHINE BREAKS OUT THAN ANTICIPATED...THIS COULD ENHANCE THE
SEVERE THREAT THIS EVE.
COLD FRONT DROPS NORTH TO SOUTH TONIGHT AND SHOULD BE PUSHING
THROUGH THE SOUTHERN PORTIONS OF THE CWA BY 7AM SUNDAY. WEDGING HIGH
PRESSURE BEHIND THIS FRONT TRAPS RESIDUAL MOISTURE ON DECREASING
N/NE WINDS...SO SHOWERS/DRIZZLE WILL PERSIST THROUGH THE NIGHT. MINS
TONIGHT WILL DROP INTO THE MID 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL RIDGE DOWN INTO THE
CAROLINAS ON SUNDAY FROM HIGH PRESSURE CENTERED OVER NORTHERN
MAINE. LOOKS LIKE COLD AIR WILL WEDGE ITSELF DOWN THE LEE OF THE
APPALACHIANS ON SUNDAY AS LINGERING TROUGH/FRONT WILL REMAIN SOUTH
AND EAST OF LOCAL AREA. THIS SHALLOW COOL AIR WILL WORK ITS WAY IN
WHILE SW FLOW ALOFT WILL ALLOW DRIER AND WARMER LAYER. OVERALL
EXPECT THIS TO PRODUCE LOW CLOUDS AND DRIZZLE/LIGHT RAIN THROUGH
SUNDAY. SHOULD BE AN INTERESTING TEMP FORECAST AS GFS KEEPS COLDER
AIR WEDGED INLAND BUT SHOWS TEMPS CLOSER TO THE UPPER 50S ALONG
THE COAST WHILE NAM SHOWS TEMPS CLOSER TO 50 TO ILM AND COASTAL
AREAS FOR SUNDAY. FOR NOW...LOWERED MAX SLIGHTLY BUT WILL NOT JUMP
TOTALLY ON NAM BANDWAGON JUST YET.
WINDS COME BACK AROUND TO THE SOUTH AT THE SURFACE IN RETURN FLOW
AHEAD OF NEXT SYSTEM APPROACHING ON SUNDAY NIGHT INTO MONDAY. A
DEEPER SOUTHERLY FLOW WILL SET UP WITH A LLJ UP TO 40 KTS PUSHING
MOISTURE BACK INTO AREA. PLENTY OF WAA WILL PRODUCE A RETURN TO
WARMER TEMPS WITH HIGHS REACHING CLOSER TO 70 ON MONDAY. SHOULD
SEE CLOUDS THROUGH THE PERIOD WITH FOG OVERNIGHT. LIGHT PCP ON
SUNDAY WILL TAPER OFF BUT GREATER CHC OF RAIN SHOWERS WILL COME ON
MONDAY AHEAD AND ALONG COLD FRONT. THE FRONT SHOULD MOVE THROUGH
BY LATE MONDAY INTO EARLY TUESDAY. GFS SHOWS PLENTY OF DRY AIR
MOVING IN BY DAYBREAK ON TUESDAY WITH PCP WATER VALUES DROPPING
FROM NEAR 1.3 INCHES DOWN TO LESS THAN A HALF INCH BY TUES
MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...SHOULD SEE A FAIRLY NICE START TO THE
PERIOD WITH DEEP W-NW FLOW AND HIGH PRESSURE BUILDING IN BEHIND
EXITING COLD FRONT. THIS WILL BE RELATIVELY SHORT LIVED AS
PROGRESSIVE FLOW KEEPS THINGS MOVING ALONG. HIGH PRESSURE WILL
SHIFT OFF SHORE AS NEXT SYSTEM MAKES ITS WAY EAST. SHOULD SEE SOME
MID TO HIGH CLOUDS BACK IN THE FORECAST BY WEDNESDAY IN W-SW FLOW
OVER THE TOP OF THE RIDGE ALOFT. WILL SEE SFC HIGH SHIFT OFF SHORE
WITH RETURN FLOW SETTING UP ONCE AGAIN AS COLD FRONT PUSHES IN
FROM THE N-NW. THIS FRONT WILL PRODUCE ANOTHER DAY OF CLOUDS AND
PCP FOR THURS INTO FRI WITH POTENTIAL FOR ANOTHER LOW PRESSURE
SYSTEM MOVING IN FROM THE GULF COAST BY THE WEEKEND.
AS FOR TEMPS...EXPECT TO SEE A GREATER DIURNAL SWING IN A DRIER
AIR MASS INITIALLY. TEMPS WILL BE INTO THE 60S DURING THE DAY BUT
TUES NIGHT AND WED NIGHT WILL HAVE BETTER RADIATIONAL COOLING WITH
LESS IN THE WAY OF CLOUDS AND LOWER DEWPOINTS. THEREFORE OVERNIGHT
LOWS SHOULD MAKE IT DOWN TO 40 OR BELOW. AS CLOUDS AND PCP RETURN
THURS AND FRI TEMPS OVERNIGHT WILL REMAIN HIGHER WITH DAYTIME
HIGHS CONTINUING TO PUSH INTO THE 60S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SHOWERS HAVE INCREASED MORE RAPIDLY AND ARE ENCOMPASSING
A WIDER AREA THAN EARLIER THOUGHT. BROKEN TO OVERCAST CLOUD VFR
CLOUD COVER WILL PERSIST THROUGH THE AFTERNOON...BUT TEMPO MVFR
VISIBILITIES WILL BE LIKELY WITH THE SHOWERS. SOUTH-SOUTHWEST TO
SOUTHWEST WINDS WITH GUSTS TO 25-28 KNOTS ARE EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING COLD FRONT. HAVE NOT OBSERVED MUCH IN THE
WAY OF SEA FOG...AND CURRENT FORECAST SURFACE WIND TRAJECTORIES
...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN THE LOW
50S...SUGGEST IF ANY SEA FOG DOES DEVELOP IT WILL BE LIGHT AND
REMAIN EAST OF THE CRE/MYR TERMINALS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME LIKELY LATE THIS
AFTERNOON AT FLO/LBT SPREADING TO THE COASTAL TERMINALS THIS
EVENING. PREDOMINATE MVFR CONDITIONS WILL BECOME LIKELY...WITH
TEMPO IFR IN THE HEAVIEST SHOWERS. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS AND WILL AMEND LATER IF NECESSARY.
HIGH CONFIDENCE IN POST-FRONTAL IFR CEILINGS AND VISIBILITIES MID TO
LATE EVENING...EXCEPT SHORTLY AFTER MIDNIGHT AT MYR/CRE. CONFIDENCE
ID MODERATE THAT FLIGHT CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT
AFTER MIDNIGHT...AND AND SOMEWHAT LOWER CONFIDENCE OF IMPROVED
CONDITIONS AFTER SUNRISE AT THE COASTAL TERMINALS.
EXTENDED OUTLOOK...POTENTIAL FOR IFR/LIFR CONDITIONS RE-DEVELOPING LATE
SUNDAY PERSISTING INTO MONDAY MORNING. ANTICIPATE VFR TO DEVELOP MONDAY
WITH EXPECTED TO CONTINUE THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...SMALL CRAFT ADVISORY IN EFFECT FOR ALL
WATERS THROUGH TONIGHT. FORECAST REMAINS ON TRACK FOR SEA
HEIGHTS...WITH 41013 REPORTING 7 FT AT 10 AM...WITH 4 FT AT 41110.
WINDS HAVE BECOME QUITE GUSTY AT FRYING PAN SHOALS...BUT COLD SHELF
WATERS ARE KEEPING WIND GUSTS DOWN IN THE INNER 20 NM. EXPECT GUSTS
TO SLOWLY INCREASE...ESPECIALLY ACROSS AMZ250 AND AMZ252...HELPING
TO FORCE WIND DRIVEN WAVES UP TO 6 FT BEFORE EASING TONIGHT. A FEW
WAVES NEAR THE OUTER 20 NM RANGE WILL REACH 8 FT LATE THIS AFTN. SW
WINDS OF 15-25 KTS WILL PERSIST THROUGH THE FRONTAL PASSAGE
TONIGHT...WHEN THEY WILL TURN TO THE NORTH AND DECREASE TO LESS THAN
15 KTS. SEAS WILL FALL IN TANDEM...BECOMING 3-4 FT WITH A NORTHERLY
CHOP BY THE END OF THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE WATERS
LATE TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...COOL BUT LIGHTER NORTHERLY FLOW WILL SET UP
OVER THE COASTAL WATERS ON SUNDAY AS COLD FRONT REMAINS JUST SOUTH
AND EAST. THIS WILL ALLOW SEAS TO RELAX DOWN LESS THAN 4 FT WITH
WINDS 15 KTS OR LESS. AS FLOW CONTINUES TO REMAIN PROGRESSIVE...AN
INCREASING RETURN FLOW WILL SET UP ONCE AGAIN LATE SUN NIGHT INTO
MON WITH WINDS INCREASING UP TO 20 KTS. THIS WILL PUSH SEAS UP
AGAIN INTO THE 3 TO 5 FT RANGE AND MAY SEE A BRIEF PERIOD OF 4 TO
6 FT SEAS BORDERING SCA THRESHOLDS MON AFTERNOON AS COLD FRONT
APPROACHES. EXPECT COLD FRONT TO MOVE THROUGH BY END OF PERIOD
WITH DECREASING OFF SHORE FLOW SETTING UP BY TUES MORNING AND SEAS
DIMINISHING.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...AS MENTIONED PREVIOUSLY THE MARINE COMMUNITY
WILL CONTINUE TO EXPERIENCE CHANGEABLE CONDITIONS IN A PROGRESSIVE
PATTERN. A MUCH LIGHTER FLOW DEVELOPS TUES INTO WED AS HIGH
PRESSURE MOVES OVER THE WATERS WITH WINDS VEERING AROUND FROM NW
TO NE. WITH WINDS REMAINING LESS THAN 10 KTS THROUGH MOST OF THE
PERIOD...SEAS WILL DIMINISH DOWN FROM 2 TO 4 FT TUES MORNING DOWN
TO LESS THAN 3 FT TUES NIGHT THROUGH WED NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR AMZ254-
256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1038 AM EST SAT JAN 21 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL MOVE
ACROSS THE COASTAL CAROLINAS LATE TONIGHT. COOL AND MOIST
CONDITIONS WILL PREVAIL ON SUNDAY AS HIGH PRESSURE BUILDS FROM THE
NORTH. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION MONDAY
NIGHT. HIGH PRESSURE WILL FOLLOW TUESDAY INTO MID WEEK...WITH
ANOTHER FRONTAL SYSTEM APPROACHING FROM THE WEST LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...CONCERN TODAY REVOLVES AROUND CONVECTION
POTENTIAL AHEAD OF A COLD FRONT APPROACHING FROM THE WEST.
COLD FRONT CURRENTLY ANALYZED TO BE JUST WEST OF THE MTNS AT THIS
TIME IS ADVANCING EAST...WITH A BAND OF PREFRONTAL SHOWERS AND TSTMS
PRECEDING IT. AHEAD OF THIS BOUNDARY...ILM CWA IS FIRMLY ENTRENCHED
IN THE WARM SECTOR WITH DEEP SW FLOW THROUGH THE COLUMN. ALL
LOCATIONS AWAY FROM THE BRUNSWICK COUNTY COAST WERE ALREADY IN THE
60S AS OF 10 AM. MAX TEMPS WILL BE TEMPERED BY SIGNIFICANT CLOUD
COVER...BUT ENOUGH BREAKS WILL ALLOW MOST LOCATIONS TO RISE TO
AROUND 70 TODAY. WITHIN THIS WARM SECTOR...WHERE CLOUDS ARE BREAKING
ACROSS THE UPSTATE OF SC...NUMEROUS SHOWERS ARE DEVELOPING AND
ADVECTING NORTHEAST INTO THIS AREA. HAVE BUMPED POP ACCORDINGLY TO
ACCOUNT FOR THIS.
MAIN IMPACTS STILL EXPECTED TO OCCUR LATE THIS AFTN AND THROUGH
EARLY TONIGHT. SPC CONTINUED THE SLIGHT RISK IN THE SWODY1 FOR
WESTERN PORTIONS...BASICALLY CKI-MAO-MEB AND WEST WITH WIND BEING
THE PRIMARY THREAT. A FEW FACTORS WORKING AGAINST A WIDESPREAD
SEVERE EVENT TODAY HOWEVER...NAMELY LACK OF PARAMETERS WORKING IN
CONCERT. ALTHOUGH SBCAPE WILL JUMP TO 300-500 J/KG OVER INLAND ZONES
(CONTAINED WITHIN THE SLIGHT RISK)...OTHER PARAMETERS APPEAR
LIMITING. 50 KTS AT 2 KFT ON LTX VWP IS ACTUALLY PROGGED TO WEAKEN
SLIGHTLY...SO LLJ WILL ONLY PEAK IN THE 40-50 KT RANGE DURING
CONVECTION. ALTHOUGH 0-6 KM SHEAR VECTOR WILL BE AROUND 40
KTS...FAVORING MULTICELLULAR STORM TYPE...AND ML LAPSE RATES IMPROVE
ABOVE 7 C/KM...THESE ARE CONFINED MOSTLY TO EASTERN ZONES. 0-3 KM
SRH SHOULD REACH 200-300 M2/S2...PRIMARILY CAUSED BY INCREASING
UNIDIRECTIONAL FLOW WITH HEIGHT...BUT IS ENHANCED IN AREAS WITH
LESSER INSTABILITY. SO...USING THE HRRR ENSEMBLE REFLECTIVITY AS A
GUIDE...EXPECT SHOWERS TO PERSIST THROUGH THE EARLY AFTN...WITH
PREFRONTAL LINE REACHING MARLBORO COUNTY BETWEEN 3P-4P...AND EXITING
OFFSHORE AROUND 9P. HAVE REMOVED MENTION OF GUSTY WINDS FROM WX
GRIDS AND EXPECT PRIMARILY A NON SEVERE EVENT. OF COURSE...CANNOT
RULE OUT AN ISOLATED DAMAGING WIND GUST...ESPECIALLY WITHIN ANY
BOWING SEGMENTS/STRUCTURES WITHIN THE LINE...BUT PRIMARY THREATS
WILL BE SUB-SEVERE WIND AND SMALL HAIL. WILL OF COURSE MONITOR...IF
MORE SUNSHINE BREAKS OUT THAN ANTICIPATED...THIS COULD ENHANCE THE
SEVERE THREAT THIS EVE.
COLD FRONT DROPS NORTH TO SOUTH TONIGHT AND SHOULD BE PUSHING
THROUGH THE SOUTHERN PORTIONS OF THE CWA BY 7AM SUNDAY. WEDGING HIGH
PRESSURE BEHIND THIS FRONT TRAPS RESIDUAL MOISTURE ON DECREASING
N/NE WINDS...SO SHOWERS/DRIZZLE WILL PERSIST THROUGH THE NIGHT. MINS
TONIGHT WILL DROP INTO THE MID 40S ACROSS THE EXTREME NORTH...TO
AROUND 50 IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...HIGH PRESSURE WILL RIDGE DOWN INTO THE
CAROLINAS ON SUNDAY FROM HIGH PRESSURE CENTERED OVER NORTHERN
MAINE. LOOKS LIKE COLD AIR WILL WEDGE ITSELF DOWN THE LEE OF THE
APPALACHIANS ON SUNDAY AS LINGERING TROUGH/FRONT WILL REMAIN SOUTH
AND EAST OF LOCAL AREA. THIS SHALLOW COOL AIR WILL WORK ITS WAY IN
WHILE SW FLOW ALOFT WILL ALLOW DRIER AND WARMER LAYER. OVERALL
EXPECT THIS TO PRODUCE LOW CLOUDS AND DRIZZLE/LIGHT RAIN THROUGH
SUNDAY. SHOULD BE AN INTERESTING TEMP FORECAST AS GFS KEEPS COLDER
AIR WEDGED INLAND BUT SHOWS TEMPS CLOSER TO THE UPPER 50S ALONG
THE COAST WHILE NAM SHOWS TEMPS CLOSER TO 50 TO ILM AND COASTAL
AREAS FOR SUNDAY. FOR NOW...LOWERED MAX SLIGHTLY BUT WILL NOT JUMP
TOTALLY ON NAM BANDWAGON JUST YET.
WINDS COME BACK AROUND TO THE SOUTH AT THE SURFACE IN RETURN FLOW
AHEAD OF NEXT SYSTEM APPROACHING ON SUNDAY NIGHT INTO MONDAY. A
DEEPER SOUTHERLY FLOW WILL SET UP WITH A LLJ UP TO 40 KTS PUSHING
MOISTURE BACK INTO AREA. PLENTY OF WAA WILL PRODUCE A RETURN TO
WARMER TEMPS WITH HIGHS REACHING CLOSER TO 70 ON MONDAY. SHOULD
SEE CLOUDS THROUGH THE PERIOD WITH FOG OVERNIGHT. LIGHT PCP ON
SUNDAY WILL TAPER OFF BUT GREATER CHC OF RAIN SHOWERS WILL COME ON
MONDAY AHEAD AND ALONG COLD FRONT. THE FRONT SHOULD MOVE THROUGH
BY LATE MONDAY INTO EARLY TUESDAY. GFS SHOWS PLENTY OF DRY AIR
MOVING IN BY DAYBREAK ON TUESDAY WITH PCP WATER VALUES DROPPING
FROM NEAR 1.3 INCHES DOWN TO LESS THAN A HALF INCH BY TUES
MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...SHOULD SEE A FAIRLY NICE START TO THE
PERIOD WITH DEEP W-NW FLOW AND HIGH PRESSURE BUILDING IN BEHIND
EXITING COLD FRONT. THIS WILL BE RELATIVELY SHORT LIVED AS
PROGRESSIVE FLOW KEEPS THINGS MOVING ALONG. HIGH PRESSURE WILL
SHIFT OFF SHORE AS NEXT SYSTEM MAKES ITS WAY EAST. SHOULD SEE SOME
MID TO HIGH CLOUDS BACK IN THE FORECAST BY WEDNESDAY IN W-SW FLOW
OVER THE TOP OF THE RIDGE ALOFT. WILL SEE SFC HIGH SHIFT OFF SHORE
WITH RETURN FLOW SETTING UP ONCE AGAIN AS COLD FRONT PUSHES IN
FROM THE N-NW. THIS FRONT WILL PRODUCE ANOTHER DAY OF CLOUDS AND
PCP FOR THURS INTO FRI WITH POTENTIAL FOR ANOTHER LOW PRESSURE
SYSTEM MOVING IN FROM THE GULF COAST BY THE WEEKEND.
AS FOR TEMPS...EXPECT TO SEE A GREATER DIURNAL SWING IN A DRIER
AIR MASS INITIALLY. TEMPS WILL BE INTO THE 60S DURING THE DAY BUT
TUES NIGHT AND WED NIGHT WILL HAVE BETTER RADIATIONAL COOLING WITH
LESS IN THE WAY OF CLOUDS AND LOWER DEWPOINTS. THEREFORE OVERNIGHT
LOWS SHOULD MAKE IT DOWN TO 40 OR BELOW. AS CLOUDS AND PCP RETURN
THURS AND FRI TEMPS OVERNIGHT WILL REMAIN HIGHER WITH DAYTIME
HIGHS CONTINUING TO PUSH INTO THE 60S.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...LIGHT RAIN NEAR LBT TO ILM WILL COME TO AN END SHORTLY
AFTER 12Z LEAVING ALL TERMINALS UNDER VFR CONDITIONS. BROKEN TO
OVERCAST CLOUD VFR CLOUD COVER WILL PERSIST THROUGH MUCH OF THE DAY.
SOUTH-SOUTHWEST TO SOUTHWEST WINDS WINDS WITH GUSTS TO 25-28 KNOTS
EXPECTED AHEAD OF AN APPROACHING COLD FRONT. FORECAST WIND
TRAJECTORIES...DEWPOINTS IN THE MID 50S AND WATER TEMPERATURES IN
THE LOW 50S...SUGGEST IF ANY SEA FOG DEVELOPS IT WILL REMAIN EAST OF
THE CRE/MYR TERMINALS.
A LINE OF CONVECTIVE SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS
WILL PRECEDE THE COLD FRONT AND AFFECT THE FLO/LBT TERMINALS 20-22Z
AND THE COASTAL TERMINALS BY 00-02Z. SINCE THUNDERSTORMS WILL BE
ISOLATED WILL NOT INCLUDE IN TAFS. TEMPO MVFR LIKELY WITH THE
SHOWERS...WITH ANY IFR TOO SHORT LIVED TO MENTION IN TAFS ATTM.
SHOWERS/MVFR CONDITIONS BECOME LIKELY AS THE COLD FRONT APPROACHES
THIS EVENING. POST FRONTAL IFR CEILINGS AND VISIBILITIES IN LIGHT
RAIN AND DRIZZLE LIKELY MID TO LATE EVENING...EXCEPT SHORTLY AFTER
MIDNIGHT AT MYR/CRE.
EXTENDED OUTLOOK...POTENTIAL MVFR CIGS/ISOLATED IFR CIGS SUNDAY.
ANTICIPATE VFR MONDAY THROUGH EXTENDED PERIOD WITH EXCEPTION OF
POSSIBLE MVFR EARLY MONDAY MORNING.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...SMALL CRAFT ADVISORY IN EFFECT FOR ALL
WATERS THROUGH TONIGHT. FORECAST REMAINS ON TRACK FOR SEA
HEIGHTS...WITH 41013 REPORTING 7 FT AT 10 AM...WITH 4 FT AT 41110.
WINDS HAVE BECOME QUITE GUSTY AT FRYING PAN SHOALS...BUT COLD SHELF
WATERS ARE KEEPING WIND GUSTS DOWN IN THE INNER 20 NM. EXPECT GUSTS
TO SLOWLY INCREASE...ESPECIALLY ACROSS AMZ250 AND AMZ252...HELPING
TO FORCE WIND DRIVEN WAVES UP TO 6 FT BEFORE EASING TONIGHT. A FEW
WAVES NEAR THE OUTER 20 NM RANGE WILL REACH 8 FT LATE THIS AFTN. SW
WINDS OF 15-25 KTS WILL PERSIST THROUGH THE FRONTAL PASSAGE
TONIGHT...WHEN THEY WILL TURN TO THE NORTH AND DECREASE TO LESS THAN
15 KTS. SEAS WILL FALL IN TANDEM...BECOMING 3-4 FT WITH A NORTHERLY
CHOP BY THE END OF THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE WATERS
LATE TONIGHT CREATING LOCALLY HIGHER WINDS AND SEAS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...COOL BUT LIGHTER NORTHERLY FLOW WILL SET UP
OVER THE COASTAL WATERS ON SUNDAY AS COLD FRONT REMAINS JUST SOUTH
AND EAST. THIS WILL ALLOW SEAS TO RELAX DOWN LESS THAN 4 FT WITH
WINDS 15 KTS OR LESS. AS FLOW CONTINUES TO REMAIN PROGRESSIVE...AN
INCREASING RETURN FLOW WILL SET UP ONCE AGAIN LATE SUN NIGHT INTO
MON WITH WINDS INCREASING UP TO 20 KTS. THIS WILL PUSH SEAS UP
AGAIN INTO THE 3 TO 5 FT RANGE AND MAY SEE A BRIEF PERIOD OF 4 TO
6 FT SEAS BORDERING SCA THRESHOLDS MON AFTERNOON AS COLD FRONT
APPROACHES. EXPECT COLD FRONT TO MOVE THROUGH BY END OF PERIOD
WITH DECREASING OFF SHORE FLOW SETTING UP BY TUES MORNING AND SEAS
DIMINISHING.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...AS MENTIONED PREVIOUSLY THE MARINE COMMUNITY
WILL CONTINUE TO EXPERIENCE CHANGEABLE CONDITIONS IN A PROGRESSIVE
PATTERN. A MUCH LIGHTER FLOW DEVELOPS TUES INTO WED AS HIGH
PRESSURE MOVES OVER THE WATERS WITH WINDS VEERING AROUND FROM NW
TO NE. WITH WINDS REMAINING LESS THAN 10 KTS THROUGH MOST OF THE
PERIOD...SEAS WILL DIMINISH DOWN FROM 2 TO 4 FT TUES MORNING DOWN
TO LESS THAN 3 FT TUES NIGHT THROUGH WED NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 5 PM EST
THIS AFTERNOON FOR AMZ254-256.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR AMZ250-252.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 AM EST SAT JAN 21 2012
.SYNOPSIS...
AN AREA OF LOW PRESSURE AND ITS ASSOCIATED FRONTAL SYSTEM WILL BRING
UNSETTLED WEATHER TO THE CAROLINAS AND SOUTHERN VIRGINIA THROUGH
TONIGHT. AN AREA OF HIGH PRESSURE WILL BUILD SOUTH INTO OUR
REGION SUNDAY...BRINGING DAMP AND CHILLY CONDITIONS. A COLD FRONT
WILL CROSS THE AREA ON MONDAY.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 925 PM FRIDAY...
THROUGH SATURDAY NIGHT: LIGHT RAIN AND A WEDGE LIKE AIR MASS HAVE
DEVELOPED FROM CENTRAL NORTH CAROLINA TO NORTHERN GA THIS
EVENING...WHILE A WARM FRONT IS STARTING TO LIFT THROUGH AL AS A
WEAK LOW PRESSURE DEVELOPS OVER ARKANSAS. THE LIGHT RAIN...SUPPORTED
BY ISENTROPIC LIFT ALONG AND NORTH OF THE WEDGE FRONT/WEAK 850
MILLIBAR WARM FRONT AND DIFFLUENT FLOW IN THE EXIT OF A WEAK 300MB
JET AXIS STRETCHED ACROSS THE LOWER MISSISSIPPI VALLEY...CONTINUES
TO BLOSSOM TO OUR SOUTHWEST AND SPREAD ACROSS CENTRAL NORTH
CAROLINA. THE ONGOING RAINFALL IS LIGHT AND RAINFALL TOTALS HAVE
BEEN BELOW A TENTH OF AN INCH. RUC ISENTROPIC LIFT FORECASTS SHOW
STRONG LIFT CONTINUING IN THE 290 TO 300 KELVIN LAYER THROUGH 09Z
BEFORE SOME DRIER AIR ALOFT..NOTED AT 700MB...ADVECTS IN FROM THE
SOUTHWEST AHEAD OF THE TROUGH AXIS TO APPROACH LATER IN THE DAY
SATURDAY. THUS..RAIN IS LIKELY TO TURN TO DRIZZLE FROM WEST TO EAST
AFTER 09Z..BUT CATEGORICAL POPS SEEM NECESSARY EVERYWHERE FOR THE
BALANCE OF THE NIGHT.
WITH A 5000 FOOT WEDGE AIR MASS (PER 00Z KGSO RAOB) LOCKING
IN...THE CURRENT FORECAST OF TEMPERATURES IN THE LOW TO MID 40S
WILL REMAINING NEARLY STEADY OR RISING SLIGHTLY LOOKS GOOD. -SMITH
THE WARM ADVECTION DRIVEN PRECIPITATION SHOULD COME TO AN END FROM
WEST TO EAST BY EARLY SATURDAY MORNING. HOWEVER...THE LULL IN
PRECIPITATION WILL BE SHORT LIVED AS A COLD FRONT ADVANCES TOWARDS
THE AREA DURING THE DAY ON SATURDAY. SOUTHWESTERLY FLOW AHEAD OF
THE FRONT WILL PUMP WARM AND MOIST AIR INTO THE REGION...WITH MAX
TEMPERATURES EXPECTED TO RISE INTO THE 60S AREAWIDE (MAYBE EVEN
PUSHING 70 DEGREES ACROSS THE SOUTHEAST). ALTHOUGH SOME DIURNAL
DESTABILIZATION IS EXPECTED TO OCCUR ACROSS THE EASTERN HALF OF
THE FORECAST AREA...DEWPOINTS ARE ONLY EXPECTED TO REACH INTO THE
LOW TO MID 50S...THUS LIMITING THE AMOUNT OF INSTABILITY. NAM
FORECAST SOUNDINGS SHOW AT BEST CAPE VALUES OF LESS THAN 500
J/KG...WHILE THE GFS FORECAST SOUNDINGS SHOW NO INSTABILITY AT
ALL. NEVERTHELESS...DECENT SHEAR WILL BE IN PLACE OVER THE REGION
AND IF WE ARE ABLE TO REALIZE SOME OF THE INSTABILITY THE NAM
INDICATES...AN ISOLATED THUNDERSTORM OR TWO CANNOT BE RULED OUT
SATURDAY AFTERNOON. HOWEVER...FOR NOW WILL LEAVE ANY MENTION OF
THUNDER OUT OF THE FORECAST DUE TO THE UNCERTAINTY.
OVERALL...AFTER THE BRIEF LULL IN PRECIPITATION SATURDAY
MORNING...AM EXPECTING A LINE OF SHOWERS TO PROGRESS FROM
NORTHWEST TO SOUTHEAST SATURDAY AFTERNOON/EVENING.
SUN AND SUN NIGHT: A STRENGTHENING 1030 MILLIBAR PLUS SURFACE COLD
AIR HIGH OVER NEW ENGLAND WILL ADVECT COLDER AND DRIER AIR INTO
CENTRAL NORTH CAROLINA DURING THE PREDAWN HOURS...AND THIS WILL SET
THE STAGE FOR A SHORT LIVED HYBRID DAMMING EVENT ON SUNDAY AS
CONTINUED SOUTHWEST FLOW ALOFT WILL SUPPORT WEAK OVERRUNNING ACROSS
CENTRAL NORTH CAROLINA AS THE NEXT PACIFIC TROUGH PUSHES EAST INTO
THE CENTRAL UNITED STATES. WITH MOIST COLUMN NOT EXTENDING MUCH
BEYOND 700 MILLIBAR...LITTLE TO NO ADDITIONAL ACCUMULATIONS ARE
EXPECTED WITH PERIODS OF DRIZZLE THROUGHOUT THE DAY...WITH THE
POTENTIAL THAT THE NORTHWEST PIEDMONT COULD SEE A BRIEF PERIOD OF
FREEZING DRIZZLE EARLY SUNDAY MORNING AS MODEL SOUNDINGS DRIVE
SURFACE TEMPERATURES SUNDAY MORNING INTO THE LOWER TO MID 30S WITH
WET BULB FREEZING LINE DEPICTED IN THE SAME CLIMATOLOGICALLY FAVORED
AREA AS WELL. FURTHERMORE A HANDFUL OF SREF MEMBERS ALSO INDICATE A
BRIEF CHANGEOVER OF FREEZING DRIZZLE WITH LITTLE TO NO ACCUMULATION(
A COUPLE OF HUNDREDTHS OR LESS). SURFACE WET BULBS ARE EXPECTED TO
REBOUND INTO THE MID 30S THROUGH THE MORNING WITH MINIMAL RECOVERY
THROUGHOUT THE DAY. AFTER MORNING LOWS IN THE MID TO UPPER 30S NORTH
TO MID 40S SOUTH...EXPECT A NET INCREASE OF ONLY 3 TO 5 DEGREES
ACROSS THE AREA.
STALLED FRONTAL ZONE SOUTH OF THE AREA BEGINS TO RETREAT NORTHWARD
AS A WARM FRONT SUNDAY NIGHT...WITH THE SOUTHERN RETURN FLOW
OVERTAKING THE SHALLOW COLD AIR DAMMING AIR MASS ALONG THE
SOUTHERN AND EASTERN FLANKS...WHILE REMAINING LOCKED IN OVER THE
NORTHWEST PIEDMONT REGION. THIS WILL FAVOR NEAR STEADY
TEMPERATURES OVERNIGHT ACROSS THE NORTHWEST WITH TEMPERATURES
SLIGHTLY RISING ACROSS THE SANDHILLS AND COASTAL COUNTIES.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 250 AM SATURDAY...
MON AND MON NIGHT: A TRANSITION FROM A FORMIDABLE CAD REGIME -- BY
THIS TIME AN IN-SITU ONE OWING TO THE QUICK DEPARTURE OF THE
PROGRESSIVE PARENT HIGH -- TO BRIEF WARM SECTOR OVER AT LEAST
SIZABLE PORTION OF CENTRAL NC...TO A COLD FRONTAL PASSAGE...WILL ALL
OCCUR IN LESS THAN 24 HOURS THIS PERIOD. THE WEDGE IS EXPECTED TO
QUICKLY ERODE ALONG THE EDGES WHERE THE CHARACTERISTIC STABILITY AND
DEPTH ARE LOWER THROUGH MIDDAY...BUT HOLD STUBBORNLY IN THE HEART OF
THE WEDGE OVER THE NW PIEDMONT INTO THE EARLY AFTERNOON HOURS...BEST
REPRESENTED BY THE 00Z ECMWF AND NAM/WRF (DESPITE THE NAM/WRF
DISCOUNTED SOLUTION OF A MUCH FARTHER NORTHWARD-DISPLACED SURFACE
LOW IN SOUTHERN CANADA...AS OPPOSED TO THE CONSENSUS OF OTHER
GUIDANCE WHICH HAS THE LOW IN THE UPPER MIDWEST). AS
SUCH...TEMPERATURES SHOULD WARM INTO THE UPPER 60S-LOWER 70S IN WAA
AND A FEW BINOVC OVER EASTERN NC...INCLUDING THE RAH COASTAL
PLAIN...WHILE THE NW PIEDMONT IS APT TO STRUGGLE THROUGH THE 40S FOR
MUCH OF THE DAY...AND TOP OUT ONLY IN THE MID-UPPER 50S FOR A COUPLE
OF HOURS VERY LATE IN THE AFTERNOON. NWP GUIDANCE INDICATES ONLY A
BRIEF PERIOD OF DEEP MOISTENING AND MID LEVEL CAP EROSION
IMMEDIATELY AHEAD OF THE FRONT...AND EVEN THEN LAPSE RATES ARE
PROJECTED TO REMAIN PSEUDO-MOIST ADIABATIC OWING TO THE PASSAGE OF
THE PARENT NEGATIVELY-TILTED S/W TROUGH AND ACCOMPANYING CAA ALOFT
TO THE NW OF THE WARM SECTOR OVER CENTRAL AND EASTERN NC. AS
SUCH...THUNDER POTENTIAL IS QUITE LOW...AND THE PROBABILITY OF
SHOWERS WILL BE HELD IN THE 30-60 PERCENT RANGE...HIGHEST NORTH AND
NORTHWEST IN CLOSER PROXIMITY TO BOTH THE S/W TROUGH ALOFT AND THE
RETREATING/ERODING WEDGE FRONT. TIMING DIFFERENCES REMAIN WRT THE
FRONTAL PASSAGE AND FOLLOWING CAA MON NIGHT...SO ONLY MINOR
MODIFICATION TO LOWS IN THE UPPER 30S TO MID-UPPER 40S WAS
JUSTIFIED.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...
TUE THROUGH FRI: MILD POST-FRONTAL HIGH PRESSURE WILL FOLLOW FOR THE
MIDDLE OF THE WEEK...WITH TEMPERATURES RANGING FROM THE UPPER 50S TO
MIDDLE 60S FOR HIGHS...WARMEST THU. NWP GUIDANCE CONTINUES TO
INDICATE THE FRONTAL ZONE FORECAST TO CROSS OUR REGION MON NIGHT
WILL STALL OVER THE GULF COAST...BUT SOLUTIONS VARY WILDLY WRT TO
HOW QUICKLY AND PHASED WITH THE NORTHERN STREAM (IF AT ALL) A
SOUTHERN STREAM UPPER LOW WILL PROGRESS EASTWARD AND ACTIVATE THE
STALLED FRONTAL ZONE WITH OUR ENSUING NEXT CHANCE OF RAIN. WILL
ACCORDINGLY MAINTAIN FORECAST CONTINUITY FROM PREVIOUS
SHIFTS...WHICH DEPICTS SLIGHT TO LOW CHANCE PROBABILITIES WED NIGHT
ONWARD AND ACCOUNTS FOR THE INHERENT FORECAST UNCERTAINTY.
HOWEVER...REALISTICALLY THERE WILL BE ONLY A COUPLE OF RELATIVELY
BRIEF BOUTS...ON THE ORDER OF SIX HOURS AT A TIME...OF RAINFALL
DURING THE ENTIRE PERIOD - ONE WITH THE NORTHWARD RETREAT OF THE
FRONTAL ZONE AHEAD OF THE INEVITABLE SURFACE LOW ATTENDING THE
SOUTHERN STREAM...AND ANOTHER WITH THE TRAILING COLD FRONT.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 120 AM...
MOSTLY LIFR CEILINGS NORTHWEST PIEDMONT WITH IFR TO MVFR
ELSEWHERE. MOSTLY MVFR VISIBILITIES IN AREAS OF RAIN. SOME
IMPROVEMENT IN CEILINGS AFTER SUNRISE... ESPECIALLY LATE AFTERNOON
INTO EARLY EVENING AS CHARACTER OF PRECIPITATION CHANGES FROM
RAIN TO SHOWERS. CONDITIONS DETERIORATE IN THE EARLY EVENING TO
IFR TO MVFR CEILINGS WITH MVFR VISIBILITIES IN PRECIPITATION.
SUB VFR CONDITIONS DOMINATE INTO MONDAY MORNING. THEN VFR INTO
WEDNESDAY EVENING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
NEAR TERM...SMITH/KRR
SHORT TERM...MWS
LONG TERM...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
121 AM EST SAT JAN 21 2012
.SYNOPSIS...
AN AREA OF LOW PRESSURE AND ITS ASSOCIATED FRONTAL SYSTEM WILL BRING
UNSETTLED WEATHER TO THE CAROLINAS AND SOUTHERN VIRGINIA THROUGH
TONIGHT. AN AREA OF HIGH PRESSURE WILL BUILD SOUTH INTO OUR
REGION SUNDAY...BRINGING DAMP AND CHILLY CONDITIONS. A COLD FRONT
WILL CROSS THE AREA ON MONDAY.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 925 PM FRIDAY...
THROUGH SATURDAY NIGHT: LIGHT RAIN AND A WEDGE LIKE AIR MASS HAVE
DEVELOPED FROM CENTRAL NORTH CAROLINA TO NORTHERN GA THIS
EVENING...WHILE A WARM FRONT IS STARTING TO LIFT THROUGH AL AS A
WEAK LOW PRESSURE DEVELOPS OVER ARKANSAS. THE LIGHT RAIN...SUPPORTED
BY ISENTROPIC LIFT ALONG AND NORTH OF THE WEDGE FRONT/WEAK 850
MILLIBAR WARM FRONT AND DIFFLUENT FLOW IN THE EXIT OF A WEAK 300MB
JET AXIS STRETCHED ACROSS THE LOWER MISSISSIPPI VALLEY...CONTINUES
TO BLOSSOM TO OUR SOUTHWEST AND SPREAD ACROSS CENTRAL NORTH
CAROLINA. THE ONGOING RAINFALL IS LIGHT AND RAINFALL TOTALS HAVE
BEEN BELOW A TENTH OF AN INCH. RUC ISENTROPIC LIFT FORECASTS SHOW
STRONG LIFT CONTINUING IN THE 290 TO 300 KELVIN LAYER THROUGH 09Z
BEFORE SOME DRIER AIR ALOFT..NOTED AT 700MB...ADVECTS IN FROM THE
SOUTHWEST AHEAD OF THE TROUGH AXIS TO APPROACH LATER IN THE DAY
SATURDAY. THUS..RAIN IS LIKELY TO TURN TO DRIZZLE FROM WEST TO EAST
AFTER 09Z..BUT CATEGORICAL POPS SEEM NECESSARY EVERYWHERE FOR THE
BALANCE OF THE NIGHT.
WITH A 5000 FOOT WEDGE AIR MASS (PER 00Z KGSO RAOB) LOCKING
IN...THE CURRENT FORECAST OF TEMPERATURES IN THE LOW TO MID 40S
WILL REMAINING NEARLY STEADY OR RISING SLIGHTLY LOOKS GOOD. -SMITH
THE WARM ADVECTION DRIVEN PRECIPITATION SHOULD COME TO AN END FROM
WEST TO EAST BY EARLY SATURDAY MORNING. HOWEVER...THE LULL IN
PRECIPITATION WILL BE SHORT LIVED AS A COLD FRONT ADVANCES TOWARDS
THE AREA DURING THE DAY ON SATURDAY. SOUTHWESTERLY FLOW AHEAD OF
THE FRONT WILL PUMP WARM AND MOIST AIR INTO THE REGION...WITH MAX
TEMPERATURES EXPECTED TO RISE INTO THE 60S AREAWIDE (MAYBE EVEN
PUSHING 70 DEGREES ACROSS THE SOUTHEAST). ALTHOUGH SOME DIURNAL
DESTABILIZATION IS EXPECTED TO OCCUR ACROSS THE EASTERN HALF OF
THE FORECAST AREA...DEWPOINTS ARE ONLY EXPECTED TO REACH INTO THE
LOW TO MID 50S...THUS LIMITING THE AMOUNT OF INSTABILITY. NAM
FORECAST SOUNDINGS SHOW AT BEST CAPE VALUES OF LESS THAN 500
J/KG...WHILE THE GFS FORECAST SOUNDINGS SHOW NO INSTABILITY AT
ALL. NEVERTHELESS...DECENT SHEAR WILL BE IN PLACE OVER THE REGION
AND IF WE ARE ABLE TO REALIZE SOME OF THE INSTABILITY THE NAM
INDICATES...AN ISOLATED THUNDERSTORM OR TWO CANNOT BE RULED OUT
SATURDAY AFTERNOON. HOWEVER...FOR NOW WILL LEAVE ANY MENTION OF
THUNDER OUT OF THE FORECAST DUE TO THE UNCERTAINTY.
OVERALL...AFTER THE BRIEF LULL IN PRECIPITATION SATURDAY
MORNING...AM EXPECTING A LINE OF SHOWERS TO PROGRESS FROM
NORTHWEST TO SOUTHEAST SATURDAY AFTERNOON/EVENING.
SUN AND SUN NIGHT: A STRENGTHENING 1030 MILLIBAR PLUS SURFACE COLD
AIR HIGH OVER NEW ENGLAND WILL ADVECT COLDER AND DRIER AIR INTO
CENTRAL NORTH CAROLINA DURING THE PREDAWN HOURS...AND THIS WILL SET
THE STAGE FOR A SHORT LIVED HYBRID DAMMING EVENT ON SUNDAY AS
CONTINUED SOUTHWEST FLOW ALOFT WILL SUPPORT WEAK OVERRUNNING ACROSS
CENTRAL NORTH CAROLINA AS THE NEXT PACIFIC TROUGH PUSHES EAST INTO
THE CENTRAL UNITED STATES. WITH MOIST COLUMN NOT EXTENDING MUCH
BEYOND 700 MILLIBAR...LITTLE TO NO ADDITIONAL ACCUMULATIONS ARE
EXPECTED WITH PERIODS OF DRIZZLE THROUGHOUT THE DAY...WITH THE
POTENTIAL THAT THE NORTHWEST PIEDMONT COULD SEE A BRIEF PERIOD OF
FREEZING DRIZZLE EARLY SUNDAY MORNING AS MODEL SOUNDINGS DRIVE
SURFACE TEMPERATURES SUNDAY MORNING INTO THE LOWER TO MID 30S WITH
WET BULB FREEZING LINE DEPICTED IN THE SAME CLIMATOLOGICALLY FAVORED
AREA AS WELL. FURTHERMORE A HANDFUL OF SREF MEMBERS ALSO INDICATE A
BRIEF CHANGEOVER OF FREEZING DRIZZLE WITH LITTLE TO NO ACCUMULATION(
A COUPLE OF HUNDREDTHS OR LESS). SURFACE WET BULBS ARE EXPECTED TO
REBOUND INTO THE MID 30S THROUGH THE MORNING WITH MINIMAL RECOVERY
THROUGHOUT THE DAY. AFTER MORNING LOWS IN THE MID TO UPPER 30S NORTH
TO MID 40S SOUTH...EXPECT A NET INCREASE OF ONLY 3 TO 5 DEGREES
ACROSS THE AREA.
STALLED FRONTAL ZONE SOUTH OF THE AREA BEGINS TO RETREAT NORTHWARD
AS A WARM FRONT SUNDAY NIGHT...WITH THE SOUTHERN RETURN FLOW
OVERTAKING THE SHALLOW COLD AIR DAMMING AIR MASS ALONG THE
SOUTHERN AND EASTERN FLANKS...WHILE REMAINING LOCKED IN OVER THE
NORTHWEST PIEDMONT REGION. THIS WILL FAVOR NEAR STEADY
TEMPERATURES OVERNIGHT ACROSS THE NORTHWEST WITH TEMPERATURES
SLIGHTLY RISING ACROSS THE SANDHILLS AND COASTAL COUNTIES.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 250 AM SATURDAY...
MON AND MON NIGHT: A TRANSITION FROM A FORMIDABLE CAD REGIME -- BY
THIS TIME AN IN-SITU ONE OWING TO THE QUICK DEPARTURE OF THE
PROGRESSIVE PARENT HIGH -- TO BRIEF WARM SECTOR OVER AT LEAST
SIZABLE PORTION OF CENTRAL NC...TO A COLD FRONTAL PASSAGE...WILL ALL
OCCUR IN LESS THAN 24 HOURS THIS PERIOD. THE WEDGE IS EXPECTED TO
QUICKLY ERODE ALONG THE EDGES WHERE THE CHARACTERISTIC STABILITY AND
DEPTH ARE LOWER THROUGH MIDDAY...BUT HOLD STUBBORNLY IN THE HEART OF
THE WEDGE OVER THE NW PIEDMONT INTO THE EARLY AFTERNOON HOURS...BEST
REPRESENTED BY THE 00Z ECMWF AND NAM/WRF (DESPITE THE NAM/WRF
DISCOUNTED SOLUTION OF A MUCH FARTHER NORTHWARD-DISPLACED SURFACE
LOW IN SOUTHERN CANADA...AS OPPOSED TO THE CONSENSUS OF OTHER
GUIDANCE WHICH HAS THE LOW IN THE UPPER MIDWEST). AS
SUCH...TEMPERATURES SHOULD WARM INTO THE UPPER 60S-LOWER 70S IN WAA
AND A FEW BINOVC OVER EASTERN NC...INCLUDING THE RAH COASTAL
PLAIN...WHILE THE NW PIEDMONT IS APT TO STRUGGLE THROUGH THE 40S FOR
MUCH OF THE DAY...AND TOP OUT ONLY IN THE MID-UPPER 50S FOR A COUPLE
OF HOURS VERY LATE IN THE AFTERNOON. NWP GUIDANCE INDICATES ONLY A
BRIEF PERIOD OF DEEP MOISTENING AND MID LEVEL CAP EROSION
IMMEDIATELY AHEAD OF THE FRONT...AND EVEN THEN LAPSE RATES ARE
PROJECTED TO REMAIN PSEUDO-MOIST ADIABATIC OWING TO THE PASSAGE OF
THE PARENT NEGATIVELY-TILTED S/W TROUGH AND ACCOMPANYING CAA ALOFT
TO THE NW OF THE WARM SECTOR OVER CENTRAL AND EASTERN NC. AS
SUCH...THUNDER POTENTIAL IS QUITE LOW...AND THE PROBABILITY OF
SHOWERS WILL BE HELD IN THE 30-60 PERCENT RANGE...HIGHEST NORTH AND
NORTHWEST IN CLOSER PROXIMITY TO BOTH THE S/W TROUGH ALOFT AND THE
RETREATING/ERODING WEDGE FRONT. TIMING DIFFERENCES REMAIN WRT THE
FRONTAL PASSAGE AND FOLLOWING CAA MON NIGHT...SO ONLY MINOR
MODIFICATION TO LOWS IN THE UPPER 30S TO MID-UPPER 40S WAS
JUSTIFIED.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...
TUE THROUGH FRI: MILD POST-FRONTAL HIGH PRESSURE WILL FOLLOW FOR THE
MIDDLE OF THE WEEK...WITH TEMPERATURES RANGING FROM THE UPPER 50S TO
MIDDLE 60S FOR HIGHS...WARMEST THU. WHILE NWP GUIDANCE CONTINUES TO
INDICATE THE FRONTAL ZONE FORECAST TO CROSS OUR REGION MON NIGHT
WILL STALL OVER THE GULF COAST...BUT SOLUTIONS VARY WILDLY WRT TO
HOW QUICKLY AND PHASED WITH THE NORTHERN STREAM (IF AT ALL) A
SOUTHERN STREAM UPPER LOW WILL PROGRESS EASTWARD AND ACTIVATE THE
STALLED FRONTAL ZONE WITH OUR ENSUING NEXT CHANCE OF RAIN. WILL
ACCORDINGLY MAINTAIN FORECAST CONTINUITY FROM PREVIOUS
SHIFTS...WHICH DEPICTS SLIGHT TO LOW CHANCE PROBABILITIES WED NIGHT
ONWARD AND ACCOUNTS FOR THE INHERENT FORECAST UNCERTAINTY.
HOWEVER... REALISTICALLY THERE WILL BE ONLY A COUPLE OF RELATIVELY
BRIEF BOUTS...ON THE ORDER OF SIX HOURS AT A TIME...OF RAINFALL
DURING THE ENTIRE PERIOD - ONE WITH THE NORTHWARD RETREAT OF THE
FRONTAL ZONE AHEAD OF THE INEVITABLE SURFACE LOW ATTENDING THE
SOUTHERN STREAM...AND ANOTHER WITH THE TRAILING COLD FRONT.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 120 AM...
MOSTLY LIFR CEILINGS NORTHWEST PIEDMONT WITH IFR TO MVFR
ELSEWHERE. MOSTLY MVFR VISIBILITIES IN AREAS OF RAIN. SOME
IMPROVEMENT IN CEILINGS AFTER SUNRISE... ESPECIALLY LATE AFTERNOON
INTO EARLY EVENING AS CHARACTER OF PRECIPITATION CHANGES FROM
RAIN TO SHOWERS. CONDITIONS DETERIORATE IN THE EARLY EVENING TO
IFR TO MVFR CEILINGS WITH MVFR VISIBILITIES IN PRECIPITATION.
SUB VFR CONDITIONS DOMINATE INTO MONDAY MORNING. THEN VFR INTO
WEDNESDAY EVENING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
NEAR TERM...SMITH/KRR
SHORT TERM...MWS
LONG TERM...MWS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
940 AM CST SAT JAN 21 2012
.DISCUSSION...FORECAST CHALLENGE CONCERNS WIND AND TEMPERATURES.
WARM ADVECTION AND STIFF SE WINDS TO CONTINUE TODAY. RUC SOUNDINGS
INDICATING 30-40KTS AT 925MB HOWEVER MIXED LAYER VERY SHALLOW SO NOT
CONFIDENT STRONGER WINDS WILL MIX DOWN. WILL BE WINDY BUT FEELING
NOW IS WINDS WILL STAY BLO ADVISORY CRITERIA. OTHERWISE CANADIAN
RADARS INDICATING -SN BREAKING OUT ACROSS SOUTHERN PRAIRIE PROVINCES
ON LEADING EDGE OF WARM ADVECTION. MOST LOOKS WELL NORTH OF BORDER
BUT WILL NOT HURT TO MAINTAIN SLIVER OF LOW POPS ALONG BORDER.
TEMPERATURES CLIMBING A LITTLE AHEAD OF SCHEDULE BUT WITH MORE
CLOUDS THAN SUN TODAY FEEL MAXIMUM VALUES IN LINE. WILL MAKE SOME
MINOR ADJUSTMENTS BUT OVERALL CURRENT FORECAST LOOKS GOOD.
&&
.AVIATION...
VFR CEILINGS WILL PERSIST THROUGH AT LEAST 21 UTC...AND THEN
SLOWLY BEGIN TO FALL LATE THIS AFTERNOON AND EVENING AS A LOW
PRESSURE SYSTEM MOVES INTO THE REGION. A SNOW/SLEET/FREEZING RAIN MIX
IS POSSIBLE FOR AIRFIELDS ALONG AND WEST OF THE VALLEY AFTER 00
UTC...BUT ALL PRECIPITATION SHOULD CHANGE OVER TO SNOW AROUND
SUNRISE. EXACT PRECIPITATION TIMING...PHASE AND COVERAGE IS STILL
UNCERTAIN...SO MULTIPLE TAF UPDATES ARE POSSIBLE OVER THE NEXT 24
HOURS. STRONG SOUTHERLY WIND WILL DEVELOP THIS MORNING WITH
AFTERNOON GUSTS UP TO 30 KTS. PATCH OF MVFR CIGS ACROSS EASTERN SD
AND WILL NEED TO MONITOR NORTHWARD MOVEMENT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
735 PM CST SUN JAN 22 2012
.DISCUSSION.../ISSUED AT 735 PM CST/
A COMBINATION OF FACTORS HAS DECREASED THE HAZARDOUS WINTER WEATHER
THREAT FOR MUCH OF THE AREA...NAMELY WEST AND NORTH. LESSER SUPPORT
FOR SNOW ESPECIALLY ANYTHING BEYOND QUITE LIGHT SNOW SEEMS OBVIOUS.
SLIGHTLY LESSER WINDS THAN EARLIER EXPECTED ALONG WITH TEMPERATURES
AND EVEN DEWPOINTS GOING TO FREEZING OR ABOVE EARLY THIS EVENING IN
THE SOUTHWEST WHERE THE STRONGEST WINDS HAVE BEEN BLOWING ALL MEAN
THAT A WINTER WX ADVISORY SEEMS NO LONGER NEEDED. HOWEVER THE SYSTEM
IS TAKING BETTER DEFINITION IN OUR SOUTHEAST AREA INCLUDING
NORTHWEST IOWA SO WILL KEEP THE ADVISORY THERE...AND FOR NOW WILL
KEEP THROUGH NOON MONDAY ALTHOUGH NOT SURE IF BLOWING SNOW WILL BE
BAD ENOUGH.ASIDE FROM THAT BIT OF WARMING WITH THE MIXING
TEMPERATURES NOT TOO BAD...MAY WIND UP SLIGHTLY LESS COLD BUT WILL
CERTAINLY FALL TOWARD MORNING. AMOUNTS IN REMAINING ADVISORY AREA
SHOULD BE 2 TO 3 INCHES BUT THERE COULD BE SOME PLACES WITH A BIT
MORE. / WILLIAMS
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
MVFR-IFR CONDITIONS WITH AREAS OF SNOW WILL BE GENERAL RULE THIS
EVENING...WITH WORST CONDITIONS CURRENTLY LOOKING TO PASS THROUGH
NORTHWEST IOWA/PARTS OF SOUTHWEST MINNESOTA AS HEAVIER BAND WHICH
HAS DEVELOPED BETWEEN KFSD AND KSUX MOVES SLOWLY EAST. KSUX SHOULD
SEE WORST OF THIS BAND...WITH KFSD/KHON AND OTHER AREAS WEST OF A
KYKN-KFSD-KMML LINE LEAN TOWARD MVFR-VFR CEILINGS AND IFR-MVFR
VISIBILITIES. CONDITIONS EXPECTED TO GRADUALLY IMPROVE WEST TO EAST
06Z-12Z...THOUGH MVFR VISIBILITIES IN BLOWING SNOW LIKELY TO LINGER
EAST OF I-29 BEYOND 12Z AS NORTHWEST WINDS INCREASE. GUSTS 25-30KTS
LIKELY MOST AREAS OVERNIGHT THROUGH MONDAY MORNING. BY 18Z MONDAY...
VFR CONDITIONS EXPECTED IN MOST AREAS...WITH WINDS DIMINISHING
SLIGHTLY WEST TO EAST THROUGH THE END OF THE TAF PERIOD.
&&
.PREV DISCUSSION.../ISSUED AT 336 PM CST/
CHALLENGE IS AT HIGH LEVEL WITH SYSTEM IN THE SHORT TERM...DEALING
WITH A HEALTHY SPLIT FLOW. WATER VAPOR IMAGERY SHOWING FULL LATITUDE
TROUGH PUSH ACROSS THE CENTRAL U.S...WITH SEVERAL PIECES OF ENERGY.
FIRST HAS MOVED PAST AND INTO NORTHWEST MN...SECOND IS LIFTING
THROUGH CENTRAL NEBRASKA...AND THIRD /THE STRONGEST/ LIFTING AROUND
THE BASE IN SOUTHERN KS. THE LATTER WILL DRIVE INTENSE CYCLOGENESIS
WELL EAST OF THE AREA LATER TONIGHT AND MONDAY WITH ITS OWN IMPACT
BEING WINDS...BUT FOCUS WILL BE ON THE MID FEATURE FOR THE EVENING.
LEADING BOUNDARY/INVERTED TROUGH NOW SHIFTED TO NEAR A KRWF TO KSUX
LINE...AND COLLAPSING SOUTHEAST AS ENERGY IN SOUTHERN TROUGH LIFTS
NORTHWARD. TEMPS AHEAD ACROSS NORTHWEST IOWA AREA ALL AT OR ABOVE
FREEZING NOW...WITH THE ONLY AREA STILL HAVING SOME PATCHY FREEZING
DRIZZLE FAR EASTERN SECTIONS OF SW MN AROUND KMWM/KMJQ/KOTG.
SNOWFALL ACROSS MUCH OF THE STATE OTHER THAN THE FAR SOUTHEAST AT
MID AFTERNOON...IN BROAD DIV Q ASSOCIATED WITH THE TROUGH.
PRECIPITATION IS ALSO BREAKING OUT ALONG THE LEADING PV SUPPORT
THROUGH NEBRASKA INTO SOUTHEAST SOUTH DAKOTA. EARLIER MINOR WARM
NOTCH NOTED ON MORNING RAOBS HAS APPARENTLY BEEN WORKED OUT
WITH PRECIPITATION ALL SNOW AT YANKTON PER LATEST WEBCAM IMAGE.
SHORT RANGE MODELS FAIL ON QPF BEING IN THE RIGHT PLACE...BUT HAVE
LESSER PROBLEMS WITH THE DYNAMICS IN MOST...ESPECIALLY IN PLACEMENT
OF THE SIGNIFICANT PV FEATURES. CLOSELY FOLLOWED RUC/NAM ON
THESE...AND RESULT WAS A QUICKER EASTWARD DEVELOPMENT ALONG THE PV
ADVECTION. QUICK PEEK AT LATEST HRRR WOULD SUGGEST THE PROGRESSION
MAY BE EVEN GREATER...AS WILL BE DEMISE OF THE WESTERN SNOW AREA IN
FAVOR OF THIS DEVELOPMENT ACROSS NEBRASKA.
THERMODYNAMICALLY...THIS IS FAR FROM THE MOST EFFICIENT PROFILE WITH
MUCH OF THE LOWER PROFILES IN THE -5 TO -8C RANGE...AND THE LIFT
FAIRLY HIGH. DENDRITIC DEPTH IS LESS THAN 100 HPA...AND REALLY DO
NOT NOTE ANY SIGNIFICANT INSTABILITY TO MAKE USE OF UNTIL MID TO
LATE EVENING WITH SOME APPEARING ABOVE OF MID LEVEL FRONT...SO LOOKS
MORE OF A BROAD AND LESSER FOCUSED EVENT UNTIL BAND DEVELOPS TOWARD
THE EAST. HOWEVER...FAIRLY QUICK PERIOD OF DYNAMIC/THERMODYNAMIC
OVERLAP...SO ANY ENHANCEMENT SHOULD BE SOMEWHAT SHORT TERM...BUT
COULD GET A LITTLE TIME BOOST BY THE SLOWING OF FEATURES DURING MID
LEVEL DEVELOPMENT TO EAST. IMPACT OVERALL WAS TO LOWER SNOWFALL
AMOUNTS BY AN INCH OR SO WEST...AND RAISE BY A HALF INCH TO INCH IN
THE EAST. WHILE MOST...IF NOT ALL OF THE AREA IS LIKELY TO STAY AT
OR BELOW SNOWFALL CRITERIA FOR AN ADVISORY... IT WILL BE THE
COMBINATION OF THE SNOW AND BLOWING SNOW THAT SUPPORTS THE ADVISORY.
THIS INCLUDES AREAS FARTHER EASTWARD WHICH RECEIVED SOME HEAVIER
SNOWFALL IN LAST EVENT. MAIN PUSH OF WINDS LOOKS TO GET GOING IN
THE FAR WEST LATE AFTERNOON TO EARLY EVENING...TOWARD THE I29
CORRIDOR TOWARD MIDNIGHT...SW MN BETWEEN 06Z AND 09Z. APPEARS THAT
GUSTY 20 TO 35 MPH WIND CAN BE EXPECTED AFTER INITIAL PRESSURE RISE
SURGE...AND MORE TYPICAL THROUGH THE EAST BY MONDAY AS THE CYCLONE
STRENGTHENS TO THE EAST. CONTINUED CURRENT ADVISORY...BUT DID EXTEND
THE END TIME TO COVER THE STRONGER WINDS. ADDITIONAL AREA WAS ADDED
OVER THE REMAINDER OF THE AREA FOR THE SNOW/WIND THREAT...BUT
STARTED AS ONE GROUP RATHER THAN PIECEMEAL TO KEEP IT SIMPLE...AND
TO PICK UP ANY LINGERING FREEZING DRIZZLE IN THE FAR EAST.
ON MONDAY...CONDITIONS WILL IMPROVE SOMEWHAT OUTSIDE ANY LINGERING
SNOWFALL WHICH IS LIMITED TO THE FAR EASTERN AREA AS UPPER LOW
DEVELOPS TO THE EAST. THIS DEVELOPMENT WILL KEEP THE GRADIENT
HOLDING ON STRONG THROUGH SW MN AND INTO NW IA THROUGH AT LEAST
MIDDAY IF NOT MID AFTERNOON. FOR THIS REASON...CONTINUED ADVISORY TO
COVER THE BLOWING SNOW POTENTIAL IN THE EASTERN GROUP. TEMPERATURES
LIKELY TO STRUGGLE WITH FRESH SNOW AND MIXED START...SO DO NOT LOOK
FOR MORE THAN A 4-6 DEGREE CLIMB AS SURFACE RIDGE FROM WEST FINALLY
STARTS TO DROP OFF THE WINDS IN THE WEST DURING THE AFTERNOON.
/CHAPMAN
BRISK NORTHWEST WINDS TAPER OFF BY MONDAY NIGHT...AS THE LOW MOVES
WELL EAST OF THE FORECAST AREA AND ARCTIC HIGH PRESSURE SLIPS INTO
THE REGION. WITH A FRESH SNOWPACK...MOSTLY CLEAR SKIES AND WINDS
BECOMING LIGHT...TEMPERATURES SHOULD PLUMMET OVERNIGHT. CONTINUED TO
GO WELL BELOW GUIDANCE WHICH IS NOTORIOUS FOR BEING TOO WARM IN
THESE EVENTS. LOWS SHOULD FALL INTO THE LOWER TEENS AND SINGLE
DIGITS BELOW ZERO.
HIGH PRESSURE SHIFTS EASTWARD ON TUESDAY WHILE THE UPPER FLOW
BECOMES MORE ZONAL. MODEST WARM AIR ADVECTION WILL ALLOW
TEMPERATURES TO IMPROVE INTO THE 20S TO LOWER 30S. A WEAK UPPER
LEVEL WAVE SLIDES THROUGH THE REGION TUESDAY NIGHT WITH LITTLE
IMPACT OTHER THAN AN INCREASE IN CLOUDS.
THE MILDER PATTERN CONTINUE INTO FRIDAY WITH WEST AND SOUTHWEST
WINDS AND LOW LEVEL TEMPERATURES NEAR OR ABOVE FREEZING. EVEN WITH
925 MB TEMPERATURES AS WARM AS +6 OR +8C...IT WILL BE DIFFICULT TO
MIX TO THE SURFACE WITH THE RECENT SNOWPACK IN PLACE. HOWEVER...DO
EXPECT HIGHS TO RISE BACK ABOVE AVERAGE AND HOVER IN THE LOWER TO
MID 30S FOR MUCH OF THE FORECAST AREA. AGAIN...WENT A BIT BELOW
GUIDANCE NUMBERS DURING THE PERIOD WITH THIS IN MIND. A MID LEVEL
WAVE SLIPS ACROSS THE MISSOURI RIVER AREA THURSDAY NIGHT AND EARLY
FRIDAY WITH MEAGER MOISTURE AND LIFT. COULD SQUEEZE OUT A LITTLE
LIGHT PRECIPITATION ACROSS THE SOUTH SO WILL LEAVE MENTION OF A
SLIGHT CHANCE. A REINFORCING SHOT OF COOLER AIR WILL FOLLOW FRIDAY
NIGHT AND SATURDAY WITH BRISK NORTHWEST WINDS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR
IAZ001>003-012>014-020>022-031-032.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR
MNZ080-081-089-090.
NE...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR
NEZ013-014.
SD...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR
SDZ070-071.
&&
$$
WILLIAMS
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
649 PM CST SUN JAN 22 2012
.DISCUSSION.../ISSUED AT 336 PM CST/
CHALLENGE IS AT HIGH LEVEL WITH SYSTEM IN THE SHORT TERM...DEALING
WITH A HEALTHY SPLIT FLOW. WATER VAPOR IMAGERY SHOWING FULL LATITUDE
TROUGH PUSH ACROSS THE CENTRAL U.S...WITH SEVERAL PIECES OF ENERGY.
FIRST HAS MOVED PAST AND INTO NORTHWEST MN...SECOND IS LIFTING
THROUGH CENTRAL NEBRASKA...AND THIRD /THE STRONGEST/ LIFTING AROUND
THE BASE IN SOUTHERN KS. THE LATTER WILL DRIVE INTENSE CYCLOGENESIS
WELL EAST OF THE AREA LATER TONIGHT AND MONDAY WITH ITS OWN IMPACT
BEING WINDS...BUT FOCUS WILL BE ON THE MID FEATURE FOR THE EVENING.
LEADING BOUNDARY/INVERTED TROUGH NOW SHIFTED TO NEAR A KRWF TO KSUX
LINE...AND COLLAPSING SOUTHEAST AS ENERGY IN SOUTHERN TROUGH LIFTS
NORTHWARD. TEMPS AHEAD ACROSS NORTHWEST IOWA AREA ALL AT OR ABOVE
FREEZING NOW...WITH THE ONLY AREA STILL HAVING SOME PATCHY FREEZING
DRIZZLE FAR EASTERN SECTIONS OF SW MN AROUND KMWM/KMJQ/KOTG.
SNOWFALL ACROSS MUCH OF THE STATE OTHER THAN THE FAR SOUTHEAST AT
MID AFTERNOON...IN BROAD DIV Q ASSOCIATED WITH THE TROUGH.
PRECIPITATION IS ALSO BREAKING OUT ALONG THE LEADING PV SUPPORT
THROUGH NEBRASKA INTO SOUTHEAST SOUTH DAKOTA. EARLIER MINOR WARM
NOTCH NOTED ON MORNING RAOBS HAS APPARENTLY BEEN WORKED OUT
WITH PRECIPITATION ALL SNOW AT YANKTON PER LATEST WEBCAM IMAGE.
SHORT RANGE MODELS FAIL ON QPF BEING IN THE RIGHT PLACE...BUT HAVE
LESSER PROBLEMS WITH THE DYNAMICS IN MOST...ESPECIALLY IN PLACEMENT
OF THE SIGNIFICANT PV FEATURES. CLOSELY FOLLOWED RUC/NAM ON
THESE...AND RESULT WAS A QUICKER EASTWARD DEVELOPMENT ALONG THE PV
ADVECTION. QUICK PEEK AT LATEST HRRR WOULD SUGGEST THE PROGRESSION
MAY BE EVEN GREATER...AS WILL BE DEMISE OF THE WESTERN SNOW AREA IN
FAVOR OF THIS DEVELOPMENT ACROSS NEBRASKA.
THERMODYNAMICALLY...THIS IS FAR FROM THE MOST EFFICIENT PROFILE WITH
MUCH OF THE LOWER PROFILES IN THE -5 TO -8C RANGE...AND THE LIFT
FAIRLY HIGH. DENDRITIC DEPTH IS LESS THAN 100 HPA...AND REALLY DO
NOT NOTE ANY SIGNIFICANT INSTABILITY TO MAKE USE OF UNTIL MID TO
LATE EVENING WITH SOME APPEARING ABOVE OF MID LEVEL FRONT...SO LOOKS
MORE OF A BROAD AND LESSER FOCUSED EVENT UNTIL BAND DEVELOPS TOWARD
THE EAST. HOWEVER...FAIRLY QUICK PERIOD OF DYNAMIC/THERMODYNAMIC
OVERLAP...SO ANY ENHANCEMENT SHOULD BE SOMEWHAT SHORT TERM...BUT
COULD GET A LITTLE TIME BOOST BY THE SLOWING OF FEATURES DURING MID
LEVEL DEVELOPMENT TO EAST. IMPACT OVERALL WAS TO LOWER SNOWFALL
AMOUNTS BY AN INCH OR SO WEST...AND RAISE BY A HALF INCH TO INCH IN
THE EAST. WHILE MOST...IF NOT ALL OF THE AREA IS LIKELY TO STAY AT
OR BELOW SNOWFALL CRITERIA FOR AN ADVISORY... IT WILL BE THE
COMBINATION OF THE SNOW AND BLOWING SNOW THAT SUPPORTS THE ADVISORY.
THIS INCLUDES AREAS FARTHER EASTWARD WHICH RECEIVED SOME HEAVIER
SNOWFALL IN LAST EVENT. MAIN PUSH OF WINDS LOOKS TO GET GOING IN
THE FAR WEST LATE AFTERNOON TO EARLY EVENING...TOWARD THE I29
CORRIDOR TOWARD MIDNIGHT...SW MN BETWEEN 06Z AND 09Z. APPEARS THAT
GUSTY 20 TO 35 MPH WIND CAN BE EXPECTED AFTER INITIAL PRESSURE RISE
SURGE...AND MORE TYPICAL THROUGH THE EAST BY MONDAY AS THE CYCLONE
STRENGTHENS TO THE EAST. CONTINUED CURRENT ADVISORY...BUT DID EXTEND
THE END TIME TO COVER THE STRONGER WINDS. ADDITIONAL AREA WAS ADDED
OVER THE REMAINDER OF THE AREA FOR THE SNOW/WIND THREAT...BUT
STARTED AS ONE GROUP RATHER THAN PIECEMEAL TO KEEP IT SIMPLE...AND
TO PICK UP ANY LINGERING FREEZING DRIZZLE IN THE FAR EAST.
ON MONDAY...CONDITIONS WILL IMPROVE SOMEWHAT OUTSIDE ANY LINGERING
SNOWFALL WHICH IS LIMITED TO THE FAR EASTERN AREA AS UPPER LOW
DEVELOPS TO THE EAST. THIS DEVELOPMENT WILL KEEP THE GRADIENT
HOLDING ON STRONG THROUGH SW MN AND INTO NW IA THROUGH AT LEAST
MIDDAY IF NOT MID AFTERNOON. FOR THIS REASON...CONTINUED ADVISORY TO
COVER THE BLOWING SNOW POTENTIAL IN THE EASTERN GROUP. TEMPERATURES
LIKELY TO STRUGGLE WITH FRESH SNOW AND MIXED START...SO DO NOT LOOK
FOR MORE THAN A 4-6 DEGREE CLIMB AS SURFACE RIDGE FROM WEST FINALLY
STARTS TO DROP OFF THE WINDS IN THE WEST DURING THE AFTERNOON.
/CHAPMAN
BRISK NORTHWEST WINDS TAPER OFF BY MONDAY NIGHT...AS THE LOW MOVES
WELL EAST OF THE FORECAST AREA AND ARCTIC HIGH PRESSURE SLIPS INTO
THE REGION. WITH A FRESH SNOWPACK...MOSTLY CLEAR SKIES AND WINDS
BECOMING LIGHT...TEMPERATURES SHOULD PLUMMET OVERNIGHT. CONTINUED TO
GO WELL BELOW GUIDANCE WHICH IS NOTORIOUS FOR BEING TOO WARM IN
THESE EVENTS. LOWS SHOULD FALL INTO THE LOWER TEENS AND SINGLE
DIGITS BELOW ZERO.
HIGH PRESSURE SHIFTS EASTWARD ON TUESDAY WHILE THE UPPER FLOW
BECOMES MORE ZONAL. MODEST WARM AIR ADVECTION WILL ALLOW
TEMPERATURES TO IMPROVE INTO THE 20S TO LOWER 30S. A WEAK UPPER
LEVEL WAVE SLIDES THROUGH THE REGION TUESDAY NIGHT WITH LITTLE
IMPACT OTHER THAN AN INCREASE IN CLOUDS.
THE MILDER PATTERN CONTINUE INTO FRIDAY WITH WEST AND SOUTHWEST
WINDS AND LOW LEVEL TEMPERATURES NEAR OR ABOVE FREEZING. EVEN WITH
925 MB TEMPERATURES AS WARM AS +6 OR +8C...IT WILL BE DIFFICULT TO
MIX TO THE SURFACE WITH THE RECENT SNOWPACK IN PLACE. HOWEVER...DO
EXPECT HIGHS TO RISE BACK ABOVE AVERAGE AND HOVER IN THE LOWER TO
MID 30S FOR MUCH OF THE FORECAST AREA. AGAIN...WENT A BIT BELOW
GUIDANCE NUMBERS DURING THE PERIOD WITH THIS IN MIND. A MID LEVEL
WAVE SLIPS ACROSS THE MISSOURI RIVER AREA THURSDAY NIGHT AND EARLY
FRIDAY WITH MEAGER MOISTURE AND LIFT. COULD SQUEEZE OUT A LITTLE
LIGHT PRECIPITATION ACROSS THE SOUTH SO WILL LEAVE MENTION OF A
SLIGHT CHANCE. A REINFORCING SHOT OF COOLER AIR WILL FOLLOW FRIDAY
NIGHT AND SATURDAY WITH BRISK NORTHWEST WINDS.
&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
MVFR-IFR CONDITIONS WITH AREAS OF SNOW WILL BE GENERAL RULE THIS
EVENING...WITH WORST CONDITIONS CURRENTLY LOOKING TO PASS THROUGH
NORTHWEST IOWA/PARTS OF SOUTHWEST MINNESOTA AS HEAVIER BAND WHICH
HAS DEVELOPED BETWEEN KFSD AND KSUX MOVES SLOWLY EAST. KSUX SHOULD
SEE WORST OF THIS BAND...WITH KFSD/KHON AND OTHER AREAS WEST OF A
KYKN-KFSD-KMML LINE LEAN TOWARD MVFR-VFR CEILINGS AND IFR-MVFR
VISIBILITIES. CONDITIONS EXPECTED TO GRADUALLY IMPROVE WEST TO EAST
06Z-12Z...THOUGH MVFR VISIBILITIES IN BLOWING SNOW LIKELY TO LINGER
EAST OF I-29 BEYOND 12Z AS NORTHWEST WINDS INCREASE. GUSTS 25-30KTS
LIKELY MOST AREAS OVERNIGHT THROUGH MONDAY MORNING. BY 18Z MONDAY...
VFR CONDITIONS EXPECTED IN MOST AREAS...WITH WINDS DIMINISHING
SLIGHTLY WEST TO EAST THROUGH THE END OF THE TAF PERIOD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR IAZ001>003-
012>014-020>022-031-032.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR MNZ071-072-
080-081-089-090-097-098.
NE...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR NEZ013-014.
SD...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR SDZ056-062-
066-067-069>071.
WINTER WEATHER ADVISORY UNTIL 4 AM CST MONDAY FOR SDZ038-050-
052-053-057>060-063>065-068.
WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR SDZ039-040-
054-055-061.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
151 PM CST SAT JAN 21 2012
.DISCUSSION.../ISSUED AT 1100 AM CST/
NUMEROUS UPDATES TO THE FORECAST THIS MORNING. FIRST WAS UNEXPECTED
AREA OF PRECIPITATION WHICH BLOSSOMED EARLY THIS MORNING ACROSS FAR
EASTERN SOUTH DAKOTA...MUCH OF NORTHWEST IOWA...AND SOUTHWEST
MINNESOTA. APPARANT SOURCE OF THE SUDDEN DEVELOPMENT OF SNOWFALL
WAS SEEDER FEEDER AS BLOB OF MID LEVEL CLOUDS PUSHED ACROSS THE
AREA. LOWER CLOUDS WERE LIMITED TO A VERY DENDRITIC DEPTH OF
1500 TO 2500 FT THICKNESS BASED ON RUC/NAM MOISTURE PROFILES AND
OBSERVED CEILINGS. FURTHER SUPPORT IS THE AREA OF MID LEVEL RETURNS
NORTH OF THE CWA WHICH ARE BASED AROUND 8000-9000 FEET. AS FAST AS
PRECIPITATION DEVELOPED...THIS IS ALSO ENDING JUST AS QUICKLY AROUND
THE IMMEDIATE KFSD AREA. HOWEVER..AM WATCHING A COUPLE OF CLOUD
LAYERS ON SATELLITE MOVING DIFFERENT DIRECTION...WITH THE LAST AREA
OF MID CLOUDS IN THE JAMES VALLEY SLIDING EASTWARD. MAY GET A LITTLE
BACK EDGE RESURGENCE IN SNOWFALL AS THIS AREA OF MID CLOUDS GOES
PAST...BUT GENERALLY HAVE COVERAGE OF PRECIP SHIFTING EAST AND
OVERALL INTENSITY OF PRECIPITATION DROPPING OFF AS WELL.
LOWER CLOUDS ARE HOPELESSLY TRAPPED BELOW THE INVERSION AND CLOUD
BEARING WINDS ARE NOT SUPPORTIVE OF ANY AGGRESSIVE EASTWARD PUSH.
THEREFORE...UNLESS THE MOISTURE IS PRECIPITATED OUT OF THE LAYER...
LIKELY THAT THERE WILL BE QUITE A FEW LOW CLOUDS FOR QUITE A BIT
LONGER. RAISED THE SKYCOVER CONSIDERABLY ALONG AND EAST OF
INTERSTATE 29 THIS AFTERNOON...AND TO THE WEST HIGHER CLOUDS WILL BE
EVENING THE PLAYING FIELD WITH TIME AS WELL.
FINALLY...ISSUED A WIND ADVISORY FOR THE HIGHER ELEVATION LOCATIONS
OF SOUTH CENTRAL SD FOR REST OF THIS MORNING AND AFTERNOON...WHERE A
FEW WIND GUSTS OVER 45 MPH ARE MOST LIKELY. /CHAPMAN
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
NUMEROUS AVIATION CONCERNS THIS GO AROUND. WIDESPREAD MVFR CEILINGS
PERSIST ALONG AND EAST OF THE JAMES VALLEY. WITH MOISTURE TRAPPED
BELOW A STRONG INVERSION AND A SOUTH/SOUTHEAST WIND ADVERTISED IN
THE CLOUD BEARING LEVELS...EXPECT VERY LITTLE TO CHANGE OTHER THAN
THE TYPICAL GRADUAL LOWERING OF CEILINGS AS INVERSION SHARPENS.
WINDS WILL ALSO REMAIN STRONG WITH GUSTS OF 30 TO 35 KTS...
ESPECIALLY WEST OF INTERSTATE 29...AND THESE WINDS WILL RESULT IN
SOME AREAS OF BLOWING SNOW...BUT FAR FROM A WIDESPREAD RISK AS SOUTH
GRADIENT IS A MORE STABLE AIRFLOW. ELEVATED LOCATIONS WOULD PROBABLY
FARE THE WORST IN THIS SETUP... WHICH IS NOT WHERE TYPICAL AIRFIELDS
LOCATED. A DISTURBANCE IS EXPECTED TO SPREAD NORTHEAST ACROSS THE
BETTER LOWER TO MID LEVEL BOUNDARY LATER TONIGHT THROUGH SUNDAY
MORNING ACROSS CENTRAL SOUTH DAKOTA...SO LARGEST IMPACT FOR
PRECIPITATION DEVELOPMENT WILL LIKELY BE FOR KHON/KMHE AREAS...
PERHAPS REACHING AS FAR EAST AS INTERSTATE 29 AREA AFTER 16Z. THERE
IS A LOW CHANCE OF FREEZING RAIN IN HURON AFTER 10Z AS INITIAL PV
ADVECTION OCCURS...BUT THE PROBABILITY IS LOW ENOUGH THAT DID NOT
INCLUDE IN TAF AT THIS TIME. HOWEVER...DID MENTION RISK OF FREEZING
RAIN OR SLEET BY MID MORNING...BUT SHOULD BE A FAIRLY NARROW WINDOW
WITH CHANGEOVER TO SNOW THROUGH COOLING OF ATMOSPHERE BY 17Z AT
KHON. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 1030 AM CST/
MAIN CONCERN FOR TODAY WILL BE CLOUD COVER AND BLOWING SNOW. STRATUS
IS RETURNING NORTH THIS MORNING BETWEEN JAMES AND BIG SIOUX RIVER
WITH RETURN LOW LEVEL SELY FLOW. SO WUD EXPECT THIS STRATUS TO
CONTINUE TO ADVECT NORTH UNDER LOW LEVEL INVERSION AND RUC SEEMS TO
HANDLE THIS LOW LEVEL MOISTURE FAIRLY WELL SO WILL KEEP FAIRLY HIGH
CLOUD COVER THOSE AREA THIS MORNING WITH THE INVERSION RISING A BIT
BY AFTERNOON WHICH SHOULD HELP SCOUR IT OUT A BIT. NEXT IS THE
INCREASING SOUTHERLY WINDS AHEAD OF NEXT WAVE THAT SHOULD GUST TO 30
TO 35 MPH LATER THIS MORNING AND AFTERNOON WHICH SHOULD CREATE AREAS
OF BLOWING SNOW. WILL NOT ISSUE ANY ADVISORY AS HARD TO CREATE
WIDESPREAD BLOWING PROBLEMS WHEN LOW LEVEL MOISTURE INCREASES OVER
FRESH SNOW COVER. SO FOR NOW WILL JUST MENTION AREAS OF BLOWING SNOW
THROUGH THE EVENING HOURS. HIGH TEMPERATURES TODAY WILL AGAIN
STRUGGLE ACROSS THE EAST BUT SHOULD WARM CLOSER TO NORMAL ACROSS THE
WEST.
WITH STOUT SOUTHERLY FLOW TONIGHT...NOT EXPECTING TEMPERATURES TO
FALL MUCH AND SHOULD ACTUALLY RISE A BIT...ESPECIALLY EAST. SYSTEM
COMING OUT LATE TONIGHT AND SUNDAY A BIT SLOWER. STILL CONTINUES TO
SHOW A SPLIT FLOW SYSTEM WITH ONE SYSTEM LIFTING UP ACROSS NORTHWEST
CWA AND SOUTHERN WAVE MOVING NORTHEAST ACROSS CENTRAL PLAINS AND
THEN PHASING EAST OF I29 SUNDAY NIGHT. WITH SLOWER SPEED THERE MAY
NOT BE MUCH IF ANY PRECIPITATION ACROSS WESTERN CWA TONIGHT EXCEPT
POSSIBLY FAR WESTERN CWA AFTER 09Z. WARM ENOUGH ALOFT THAT ANY
PRECIPITATION WOULD BE FREEZING RAIN AND NOT SNOW SO WILL REMOVE
MENTION OF SNOW LATE TONIGHT. AMOUNTS IF ANY WILL BE VERY LIGHT AND
WILL NOT ISSUE ANY HEADLINE.
ON SUNDAY...SOUTHERN WAVE MAY CLIP NORTHWEST IOWA DURING THE
AFTERNOON AND WILL KEEP 40% POPS THERE AND LIKELY POPS ACROSS FAR
NORTHWEST CWA WITH NORTHERN WAVE. IN BETWEEN WILL KEEP POPS
RELATIVELY LOW IN THE 30% RANGE. DOUBT WE WILL SEE ANY FREEZING RAIN
BY LATER SUNDAY MORNING AND AFTERNOON AS AIRMASS COOLS AND ANYTHING
THAT DOES FALL WILL BE SNOW. SO WILL REMOVE ANY MENTION OF RAIN WEST
AND WILL ALSO LOWER HIGH TEMPERATURES DUE TO THE COOLING OF THE
COLUMN WITH THESE FEATURES. COULD SEE AN INCH OR TWO OF SNOW IN THE
JAMES VALLEY SUNDAY AFTERNOON. GUSTY NORTHWEST WINDS WILL DEVELOP
SUNDAY AFTERNOON ACROSS THE WESTERN CWA AS SURFACE TROF MOVES EAST
WITH COLD AIR ADVECTION BRINGING IN STRONGER WINDS. SO COULD SEE
SOME MORE BLOWING SNOW ACROSS THE WEST.
SUNDAY NIGHT WILL SEE GUSTY NORTHWEST WINDS AND AREAS OF BLOWING
SNOW WITH SOME LIGHT SNOW ACROSS THE CWA WITH PHASING UPPER TROF.
NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS WITH LESS THAN ONE
INCH EXPECTED.
ANOTHER CHILLY DAY ON MONDAY BEHIND THE WAVE WITH BELOW NORMAL
TEMPERATURES EAST WITH HIGHS IN THE TEENS TO LOWER 20S. SHOULD BE A
BIT WARMER WEST WITH HIGHS IN THE 20S. SURFACE HIGH WILL SETTLE
ACROSS THE CWA MONDAY NIGHT...AND WITH LIGHT WINDS AND FRESH SNOW
COVER...WITH GO 5 TO 10 DEGREES COLDER THAN CONSALL AND CONSRAW
WHICH ARE NOT HANDLING SNOW COVER WELL AS EVIDENT BY THE VERY COLD
TEMPERATURES THIS MORNING ACROSS MUCH OF CWA. WOULD NOT BE SUPRISED
IF A FEW LOCATIONS ACROSS THE EAST DROP BELOW ZERO EARLY TUESDAY
MORNING.
SHOULD BE WARMER ACROSS THE CWA TUESDAY THROUGH FRIDAY WITH A MORE
ZONAL FLOW...BUT SNOW COVER WILL HAVE A HUGE IMPACT...ESPECIALLY
EAST WHERE SNOW COVER IS DEEPER AND WILL NOT MELT OFF. SO MAY AT
BEST SEE HIGHS NEAR 30 ACROSS THE EAST DURING THIS TIME
PERIOD...WHILE WESTERN CWA WILL HAVE A BETTER CHANCE TO MELT AWAY
SOME OF THE SNOW AND APPROACH 40 FOR DAYTIME HIGHS...ESPECIALLY
SOUTHWEST CWA.
DOESN`T LOOK LIKE MUCH THREAT FOR ANY PRECIPITATION AFTER SUNDAY AND
WILL BASICALLY KEEP CWA DRY EXPECT FOR A VERY SLIGHT CHANCE OF LIGHT
SNOW TUESDAY NIGHT EAST OF I29 WITH VERY WEAK WAVE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY THROUGH 5 PM CST FOR SDZ050-057-063.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1100 AM CST SAT JAN 21 2012
.DISCUSSION.../ISSUED AT 1100 AM CST/
NUMEROUS UPDATES TO THE FORECAST THIS MORNING. FIRST WAS UNEXPECTED
AREA OF PRECIPITATION WHICH BLOSSOMED EARLY THIS MORNING ACROSS FAR
EASTERN SOUTH DAKOTA...MUCH OF NORTHWEST IOWA...AND SOUTHWEST
MINNESOTA. APPARANT SOURCE OF THE SUDDEN DEVELOPMENT OF SNOWFALL
WAS SEEDER FEEDER AS BLOB OF MID LEVEL CLOUDS PUSHED ACROSS THE
AREA. LOWER CLOUDS WERE LIMITED TO A VERY DENDRITIC DEPTH OF
1500 TO 2500 FT THICKNESS BASED ON RUC/NAM MOISTURE PROFILES AND
OBSERVED CEILINGS. FURTHER SUPPORT IS THE AREA OF MID LEVEL RETURNS
NORTH OF THE CWA WHICH ARE BASED AROUND 8000-9000 FEET. AS FAST AS
PRECIPITATION DEVELOPED...THIS IS ALSO ENDING JUST AS QUICKLY AROUND
THE IMMEDIATE KFSD AREA. HOWEVER..AM WATCHING A COUPLE OF CLOUD
LAYERS ON SATELLITE MOVING DIFFERENT DIRECTION...WITH THE LAST AREA
OF MID CLOUDS IN THE JAMES VALLEY SLIDING EASTWARD. MAY GET A LITTLE
BACK EDGE RESURGENCE IN SNOWFALL AS THIS AREA OF MID CLOUDS GOES
PAST...BUT GENERALLY HAVE COVERAGE OF PRECIP SHIFTING EAST AND
OVERALL INTENSITY OF PRECIPITATION DROPPING OFF AS WELL.
LOWER CLOUDS ARE HOPELESSLY TRAPPED BELOW THE INVERSION AND CLOUD
BEARING WINDS ARE NOT SUPPORTIVE OF ANY AGGRESSIVE EASTWARD PUSH.
THEREFORE...UNLESS THE MOISTURE IS PRECIPITATED OUT OF THE LAYER...
LIKELY THAT THERE WILL BE QUITE A FEW LOW CLOUDS FOR QUITE A BIT
LONGER. RAISED THE SKYCOVER CONSIDERABLY ALONG AND EAST OF
INTERSTATE 29 THIS AFTERNOON...AND TO THE WEST HIGHER CLOUDS WILL BE
EVENING THE PLAYING FIELD WITH TIME AS WELL.
FINALLY...ISSUED A WIND ADVISORY FOR THE HIGHER ELEVATION LOCATIONS
OF SOUTH CENTRAL SD FOR REST OF THIS MORNING AND AFTERNOON...WHERE A
FEW WIND GUSTS OVER 45 MPH ARE MOST LIKELY. /CHAPMAN
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
AREA OF MVFR CIGS ACROSS SOUTHEAST SOUTH DAKOTA WILL MOVE ENE THIS
MORNING AS SW WINDS DEVELOP ABOVE THE SURFACE. BASED UPON CURRENT
MOVEMENT...LOW CLOUDS SHOULD MOVE EAST OF KHON AND KFSD BY 14Z AND
KSUX BY 15Z. OTHERWISE...WINDS EXPECTED TO REALLY INCREASE THIS
MORNING WITH WINDS GUSTING OVER 30 KTS EXPECTED IN MOST AREAS BY
EARLY THIS AFTERNOON. WITH FRESH SNOW COVER EXPECT SOME BLOWING SNOW
BUT THE BOUNDARY LAYER IS RELATIVELY STABLE WITH THE WARM AIR
ADVECTION DEVELOPING SO THAT REALLY SHOULD LIMIT THE REDUCED
VISIBILITIES TO ONLY A COUPLE OF HOURS THIS AFTERNOON WHEN WINDS
ARE MOST LIKELY TO GUST OVER 30 KTS. WINDS WILL DECREASE A LITTLE
TONIGHT AND THE MID AND UPPER CLOUDS WILL MOVE OVER. WITH A STRONG
PV ANOMALY MOVING OVER THE 850 MB BOUNDARY IN CENTRAL SD LATE
TONIGHT...DID BRING MVFR CIGS BACK INTO HURON LATE TONIGHT. THERE IS
A LOW CHANCE OF FREEZING RAIN IN HURON AFTER 09Z BUT THE PROBABILITY
IS LOW ENOUGH THAT DID NOT INCLUDE IN TAF AT THIS TIME.
HOWEVER...SNOW...POSSIBLY MIXED WITH FREEZING RAIN...ARE MORE LIKELY
LATE SUNDAY MORNING AND SUNDAY AFTERNOON ACROSS MOST OF SE SD AND
WILL LIKELY IMPACT CIGS AND VSBYS./SCHUMACHER
&&
.PREV DISCUSSION.../ISSUED AT 1030 AM CST/
MAIN CONCERN FOR TODAY WILL BE CLOUD COVER AND BLOWING SNOW. STRATUS
IS RETURNING NORTH THIS MORNING BETWEEN JAMES AND BIG SIOUX RIVER
WITH RETURN LOW LEVEL SELY FLOW. SO WUD EXPECT THIS STRATUS TO
CONTINUE TO ADVECT NORTH UNDER LOW LEVEL INVERSION AND RUC SEEMS TO
HANDLE THIS LOW LEVEL MOISTURE FAIRLY WELL SO WILL KEEP FAIRLY HIGH
CLOUD COVER THOSE AREA THIS MORNING WITH THE INVERSION RISING A BIT
BY AFTERNOON WHICH SHOULD HELP SCOUR IT OUT A BIT. NEXT IS THE
INCREASING SOUTHERLY WINDS AHEAD OF NEXT WAVE THAT SHOULD GUST TO 30
TO 35 MPH LATER THIS MORNING AND AFTERNOON WHICH SHOULD CREATE AREAS
OF BLOWING SNOW. WILL NOT ISSUE ANY ADVISORY AS HARD TO CREATE
WIDESPREAD BLOWING PROBLEMS WHEN LOW LEVEL MOISTURE INCREASES OVER
FRESH SNOW COVER. SO FOR NOW WILL JUST MENTION AREAS OF BLOWING SNOW
THROUGH THE EVENING HOURS. HIGH TEMPERATURES TODAY WILL AGAIN
STRUGGLE ACROSS THE EAST BUT SHOULD WARM CLOSER TO NORMAL ACROSS THE
WEST.
WITH STOUT SOUTHERLY FLOW TONIGHT...NOT EXPECTING TEMPERATURES TO
FALL MUCH AND SHOULD ACTUALLY RISE A BIT...ESPECIALLY EAST. SYSTEM
COMING OUT LATE TONIGHT AND SUNDAY A BIT SLOWER. STILL CONTINUES TO
SHOW A SPLIT FLOW SYSTEM WITH ONE SYSTEM LIFTING UP ACROSS NORTHWEST
CWA AND SOUTHERN WAVE MOVING NORTHEAST ACROSS CENTRAL PLAINS AND
THEN PHASING EAST OF I29 SUNDAY NIGHT. WITH SLOWER SPEED THERE MAY
NOT BE MUCH IF ANY PRECIPITATION ACROSS WESTERN CWA TONIGHT EXCEPT
POSSIBLY FAR WESTERN CWA AFTER 09Z. WARM ENOUGH ALOFT THAT ANY
PRECIPITATION WOULD BE FREEZING RAIN AND NOT SNOW SO WILL REMOVE
MENTION OF SNOW LATE TONIGHT. AMOUNTS IF ANY WILL BE VERY LIGHT AND
WILL NOT ISSUE ANY HEADLINE.
ON SUNDAY...SOUTHERN WAVE MAY CLIP NORTHWEST IOWA DURING THE
AFTERNOON AND WILL KEEP 40% POPS THERE AND LIKELY POPS ACROSS FAR
NORTHWEST CWA WITH NORTHERN WAVE. IN BETWEEN WILL KEEP POPS
RELATIVELY LOW IN THE 30% RANGE. DOUBT WE WILL SEE ANY FREEZING RAIN
BY LATER SUNDAY MORNING AND AFTERNOON AS AIRMASS COOLS AND ANYTHING
THAT DOES FALL WILL BE SNOW. SO WILL REMOVE ANY MENTION OF RAIN WEST
AND WILL ALSO LOWER HIGH TEMPERATURES DUE TO THE COOLING OF THE
COLUMN WITH THESE FEATURES. COULD SEE AN INCH OR TWO OF SNOW IN THE
JAMES VALLEY SUNDAY AFTERNOON. GUSTY NORTHWEST WINDS WILL DEVELOP
SUNDAY AFTERNOON ACROSS THE WESTERN CWA AS SURFACE TROF MOVES EAST
WITH COLD AIR ADVECTION BRINGING IN STRONGER WINDS. SO COULD SEE
SOME MORE BLOWING SNOW ACROSS THE WEST.
SUNDAY NIGHT WILL SEE GUSTY NORTHWEST WINDS AND AREAS OF BLOWING
SNOW WITH SOME LIGHT SNOW ACROSS THE CWA WITH PHASING UPPER TROF.
NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS WITH LESS THAN ONE
INCH EXPECTED.
ANOTHER CHILLY DAY ON MONDAY BEHIND THE WAVE WITH BELOW NORMAL
TEMPERATURES EAST WITH HIGHS IN THE TEENS TO LOWER 20S. SHOULD BE A
BIT WARMER WEST WITH HIGHS IN THE 20S. SURFACE HIGH WILL SETTLE
ACROSS THE CWA MONDAY NIGHT...AND WITH LIGHT WINDS AND FRESH SNOW
COVER...WITH GO 5 TO 10 DEGREES COLDER THAN CONSALL AND CONSRAW
WHICH ARE NOT HANDLING SNOW COVER WELL AS EVIDENT BY THE VERY COLD
TEMPERATURES THIS MORNING ACROSS MUCH OF CWA. WOULD NOT BE SUPRISED
IF A FEW LOCATIONS ACROSS THE EAST DROP BELOW ZERO EARLY TUESDAY
MORNING.
SHOULD BE WARMER ACROSS THE CWA TUESDAY THROUGH FRIDAY WITH A MORE
ZONAL FLOW...BUT SNOW COVER WILL HAVE A HUGE IMPACT...ESPECIALLY
EAST WHERE SNOW COVER IS DEEPER AND WILL NOT MELT OFF. SO MAY AT
BEST SEE HIGHS NEAR 30 ACROSS THE EAST DURING THIS TIME
PERIOD...WHILE WESTERN CWA WILL HAVE A BETTER CHANCE TO MELT AWAY
SOME OF THE SNOW AND APPROACH 40 FOR DAYTIME HIGHS...ESPECIALLY
SOUTHWEST CWA.
DOESN`T LOOK LIKE MUCH THREAT FOR ANY PRECIPITATION AFTER SUNDAY AND
WILL BASICALLY KEEP CWA DRY EXPECT FOR A VERY SLIGHT CHANCE OF LIGHT
SNOW TUESDAY NIGHT EAST OF I29 WITH VERY WEAK WAVE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY THROUGH 5 PM CST FOR SDZ050-057-063.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
725 AM CST SAT JAN 21 2012
.UPDATE...
MINOR UPDATE THIS MORNING TO INCREASE CLOUD COVER FOR TODAY. LOW
STRATUS DECK ADVECTING NORTHWARD ALONG THE I-29 CORRIDOR QUITE
RAPIDLY THIS MORNING. 06Z RUC ALSO EXPANDS THIS AREA OF CLOUDS
NORTHWESTWARD DURING THE MORNING HOURS.
UPDATED 12Z AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...THROUGH MONDAY
WINTER CONTINUES. WITH WIDESPREAD TEMPERATURES AROUND/BELOW ZERO
THIS AM...WARM ADVECTION ALOFT WILL RESULT IN A STRONG INVERSION
JUST OFF THE SURFACE. THIS...ALONG WITH A LESS THAN FAVORABLE
MIXING DIRECTION WILL TRANSLATE THE 50KT LOW LEVEL JET OVER THE
EASTERN CWA INTO MERELY BREEZY CONDITIONS AT THE SURFACE. GIVEN
THE LIGHT POWDER...SHOULD SEE SOME BLOWING SNOW THOUGH IT IS
UNLIKELY TO RESULT IN WIDESPREAD REDUCTIONS TO VISIBILITY. WARM
ADVECTION AHEAD OF A CLIPPER SYSTEM WILL ONLY MAKE CONDITIONS MORE
HAZARDOUS AS ANY LIGHT PRECIPITATION WITHIN THE SYSTEMS WARM
SECTOR WILL RESULT IN SLEET OR FREEZING RAIN. EVEN WHERE
TEMPERATURES WARM ABOVE ZERO TODAY...THE GROUND SHOULD REMAIN VERY
COLD AND RESULT IN SOME ICING CONDITIONS. AS THE SYSTEM SLOWLY
PROGRESSES EAST...BUFKIT PROFILES INITIALLY SHOWING INTERMITTENT
LIFT/SATURATION IN THE DENDRITIC GROWTH ZONE WITH DRY/MILD LOW
LEVEL AIR MAKING PTYPE DIFFICULT TO INTERPRET TRANSITIONS TO
PROFILES CONDUCIVE FOR ALL SNOW. THE COLD ADVECTION RESPONSIBLE
FOR THIS CHANGE OVER WILL ALSO LEAD TO STRONG WINDS WITH H85 WINDS
TOPPING 60KTS...RESULT IN IN CONTINUED WINTER WEATHER IMPACTS.
GOOD MIXING INITIALLY MEANS HIGHS SUNDAY ABOVE FREEZING...WITH
TEMPERATURES FALLING THROUGH THE REST OF THE DAY.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY NIGHT
FORECAST PERIOD BEGINS WITH AN ELONGATED NORTH TO SOUTH SURFACE
HIGH PRESSURE OVER THE CWA MONDAY NIGHT. THIS SFC HIGH IS PROGGED
TO GRADUALLY SLIDE SEWD ON TUESDAY. GLOBAL MODELS THEN DROP A WEAK
CLIPPER SHORT- WAVE TROUGH SEWD THROUGH ERN ND WEDNESDAY. ANOTHER
CLIPPER WAVE IS THEN FORECAST TO MOVE EWD THROUGH CENTRAL ND
THURSDAY. LATEST MODEL RUNS ARE DRY WITH BOTH OF THE UPPER TROUGH
AND ASSOCIATED WEAK COLD FRONTAL PASSAGES...KEEPING SNOW CHANCES
IN NORTH DAKOTA. ALL IN ALL A DRY WEEK APPEARS IN STORE FOR THE
CWA WITH TEMPERATURES ABOUT 10 DEGREES ABOVE SEASONAL AVERAGES FOR
LATE JANUARY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN AREA OF MVFR CIGS WILL CONTINUE TO MOVE NORTH ALONG THE I-29
CORRIDOR THIS MORNING...IMPACTING KATY. THE CIGS WILL ALSO EXPAND
NORTHWESTWARD DURING THE MORNING HOURS. SOUTH WINDS WILL BE ON THE
INCREASE AROUND MID-MORNING WITH WINDS GUSTING TO ABOUT 30 KTS AT
ALL TAF SITES. LOW LEVEL WIND SHEAR IS EXPECTED AT KABR AND KATY
FROM APPROXIMATELY MID MORNING THROUGH THE AFTERNOON. THE STRONG
SOUTH WINDS WILL SUBSIDE DURING THE EVENING. AS AN UPPER LEVEL
TROUGH AND SFC COLD FRONT APPROACH THE REGION TONIGHT...A MIXED BAG OF
PRECIPITATION IS EXPECTED OVERNIGHT WITH -FZDZ/-PL/-SN ALONG WITH
WDSPRD IFR/LIFR CIGS AND MVFR VSBYS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 6 PM CST /5 PM MST/ THIS EVENING TO
MIDNIGHT CST /11 PM MST/ SUNDAY NIGHT FOR BROWN-CAMPBELL-
CORSON-DEWEY-EDMUNDS-FAULK-MCPHERSON-POTTER-WALWORTH.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
SUNDAY NIGHT FOR CLARK-CODINGTON-DAY-DEUEL-GRANT-HAMLIN-
MARSHALL-ROBERTS-SPINK.
MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
SUNDAY NIGHT FOR BIG STONE-TRAVERSE.
&&
$$
UPDATE...CHURCH
SHORT TERM...CONNELLY
LONG TERM...CHURCH
AVIATION...CHURCH
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
521 AM CST SAT JAN 21 2012
.DISCUSSION.../ISSUED AT 300 AM CST/
MAIN CONCERN FOR TODAY WILL BE CLOUD COVER AND BLOWING SNOW. STRATUS
IS RETURNING NORTH THIS MORNING BETWEEN JAMES AND BIG SIOUX RIVER
WITH RETURN LOW LEVEL SELY FLOW. SO WUD EXPECT THIS STRATUS TO
CONTINUE TO ADVECT NORTH UNDER LOW LEVEL INVERSION AND RUC SEEMS TO
HANDLE THIS LOW LEVEL MOISTURE FAIRLY WELL SO WILL KEEP FAIRLY HIGH
CLOUD COVER THOSE AREA THIS MORNING WITH THE INVERSION RISING A BIT
BY AFTERNOON WHICH SHOULD HELP SCOUR IT OUT A BIT. NEXT IS THE
INCREASING SOUTHERLY WINDS AHEAD OF NEXT WAVE THAT SHOULD GUST TO 30
TO 35 MPH LATER THIS MORNING AND AFTERNOON WHICH SHOULD CREATE AREAS
OF BLOWING SNOW. WILL NOT ISSUE ANY ADVISORY AS HARD TO CREATE
WIDESPREAD BLOWING PROBLEMS WHEN LOW LEVEL MOISTURE INCREASES OVER
FRESH SNOW COVER. SO FOR NOW WILL JUST MENTION AREAS OF BLOWING SNOW
THROUGH THE EVENING HOURS. HIGH TEMPERATURES TODAY WILL AGAIN
STRUGGLE ACROSS THE EAST BUT SHOULD WARM CLOSER TO NORMAL ACROSS THE
WEST.
WITH STOUT SOUTHERLY FLOW TONIGHT...NOT EXPECTING TEMPERATURES TO
FALL MUCH AND SHOULD ACTUALLY RISE A BIT...ESPECIALLY EAST. SYSTEM
COMING OUT LATE TONIGHT AND SUNDAY A BIT SLOWER. STILL CONTINUES TO
SHOW A SPLIT FLOW SYSTEM WITH ONE SYSTEM LIFTING UP ACROSS NORTHWEST
CWA AND SOUTHERN WAVE MOVING NORTHEAST ACROSS CENTRAL PLAINS AND
THEN PHASING EAST OF I29 SUNDAY NIGHT. WITH SLOWER SPEED THERE MAY
NOT BE MUCH IF ANY PRECIPITATION ACROSS WESTERN CWA TONIGHT EXCEPT
POSSIBLY FAR WESTERN CWA AFTER 09Z. WARM ENOUGH ALOFT THAT ANY
PRECIPITATION WOULD BE FREEZING RAIN AND NOT SNOW SO WILL REMOVE
MENTION OF SNOW LATE TONIGHT. AMOUNTS IF ANY WILL BE VERY LIGHT AND
WILL NOT ISSUE ANY HEADLINE.
ON SUNDAY...SOUTHERN WAVE MAY CLIP NORTHWEST IOWA DURING THE
AFTERNOON AND WILL KEEP 40% POPS THERE AND LIKELY POPS ACROSS FAR
NORTHWEST CWA WITH NORTHERN WAVE. IN BETWEEN WILL KEEP POPS
RELATIVELY LOW IN THE 30% RANGE. DOUBT WE WILL SEE ANY FREEZING RAIN
BY LATER SUNDAY MORNING AND AFTERNOON AS AIRMASS COOLS AND ANYTHING
THAT DOES FALL WILL BE SNOW. SO WILL REMOVE ANY MENTION OF RAIN WEST
AND WILL ALSO LOWER HIGH TEMPERATURES DUE TO THE COOLING OF THE
COLUMN WITH THESE FEATURES. COULD SEE AN INCH OR TWO OF SNOW IN THE
JAMES VALLEY SUNDAY AFTERNOON. GUSTY NORTHWEST WINDS WILL DEVELOP
SUNDAY AFTERNOON ACROSS THE WESTERN CWA AS SURFACE TROF MOVES EAST
WITH COLD AIR ADVECTION BRINGING IN STRONGER WINDS. SO COULD SEE
SOME MORE BLOWING SNOW ACROSS THE WEST.
SUNDAY NIGHT WILL SEE GUSTY NORTHWEST WINDS AND AREAS OF BLOWING
SNOW WITH SOME LIGHT SNOW ACROSS THE CWA WITH PHASING UPPER TROF.
NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS WITH LESS THAN ONE
INCH EXPECTED.
ANOTHER CHILLY DAY ON MONDAY BEHIND THE WAVE WITH BELOW NORMAL
TEMPERATURES EAST WITH HIGHS IN THE TEENS TO LOWER 20S. SHOULD BE A
BIT WARMER WEST WITH HIGHS IN THE 20S. SURFACE HIGH WILL SETTLE
ACROSS THE CWA MONDAY NIGHT...AND WITH LIGHT WINDS AND FRESH SNOW
COVER...WITH GO 5 TO 10 DEGREES COLDER THAN CONSALL AND CONSRAW
WHICH ARE NOT HANDLING SNOW COVER WELL AS EVIDENT BY THE VERY COLD
TEMPERATURES THIS MORNING ACROSS MUCH OF CWA. WOULD NOT BE SUPRISED
IF A FEW LOCATIONS ACROSS THE EAST DROP BELOW ZERO EARLY TUESDAY
MORNING.
SHOULD BE WARMER ACROSS THE CWA TUESDAY THROUGH FRIDAY WITH A MORE
ZONAL FLOW...BUT SNOW COVER WILL HAVE A HUGE IMPACT...ESPECIALLY
EAST WHERE SNOW COVER IS DEEPER AND WILL NOT MELT OFF. SO MAY AT
BEST SEE HIGHS NEAR 30 ACROSS THE EAST DURING THIS TIME
PERIOD...WHILE WESTERN CWA WILL HAVE A BETTER CHANCE TO MELT AWAY
SOME OF THE SNOW AND APPROACH 40 FOR DAYTIME HIGHS...ESPECIALLY
SOUTHWEST CWA.
DOESN`T LOOK LIKE MUCH THREAT FOR ANY PRECIPITATION AFTER SUNDAY AND
WILL BASICALLY KEEP CWA DRY EXPECT FOR A VERY SLIGHT CHANCE OF LIGHT
SNOW TUESDAY NIGHT EAST OF I29 WITH VERY WEAK WAVE.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
AREA OF MVFR CIGS ACROSS SOUTHEAST SOUTH DAKOTA WILL MOVE ENE THIS
MORNING AS SW WINDS DEVELOP ABOVE THE SURFACE. BASED UPON CURRENT
MOVEMENT...LOW CLOUDS SHOULD MOVE EAST OF KHON AND KFSD BY 14Z AND
KSUX BY 15Z. OTHERWISE...WINDS EXPECTED TO REALLY INCREASE THIS
MORNING WITH WINDS GUSTING OVER 30 KTS EXPECTED IN MOST AREAS BY
EARLY THIS AFTERNOON. WITH FRESH SNOW COVER EXPECT SOME BLOWING SNOW
BUT THE BOUNDARY LAYER IS RELATIVELY STABLE WITH THE WARM AIR
ADVECTION DEVELOPING SO THAT REALLY SHOULD LIMIT THE REDUCED
VISIBILITIES TO ONLY A COUPLE OF HOURS THIS AFTERNOON WHEN WINDS
ARE MOST LIKELY TO GUST OVER 30 KTS. WINDS WILL DECREASE A LITTLE
TONIGHT AND THE MID AND UPPER CLOUDS WILL MOVE OVER. WITH A STRONG
PV ANOMALY MOVING OVER THE 850 MB BOUNDARY IN CENTRAL SD LATE
TONIGHT...DID BRING MVFR CIGS BACK INTO HURON LATE TONIGHT. THERE IS
A LOW CHANCE OF FREEZING RAIN IN HURON AFTER 09Z BUT THE PROBABILITY
IS LOW ENOUGH THAT DID NOT INCLUDE IN TAF AT THIS TIME.
HOWEVER...SNOW...POSSIBLY MIXED WITH FREEZING RAIN...ARE MORE LIKELY
LATE SUNDAY MORNING AND SUNDAY AFTERNOON ACROSS MOST OF SE SD AND
WILL LIKELY IMPACT CIGS AND VSBYS./SCHUMACHER
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
310 AM CST SAT JAN 21 2012
.DISCUSSION.../ISSUED AT 300 AM CST/
MAIN CONCERN FOR TODAY WILL BE CLOUD COVER AND BLOWING SNOW. STRATUS
IS RETURNING NORTH THIS MORNING BETWEEN JAMES AND BIG SIOUX RIVER
WITH RETURN LOW LEVEL SELY FLOW. SO WUD EXPECT THIS STRATUS TO
CONTINUE TO ADVECT NORTH UNDER LOW LEVEL INVERSION AND RUC SEEMS TO
HANDLE THIS LOW LEVEL MOISTURE FAIRLY WELL SO WILL KEEP FAIRLY HIGH
CLOUD COVER THOSE AREA THIS MORNING WITH THE INVERSION RISING A BIT
BY AFTERNOON WHICH SHOULD HELP SCOUR IT OUT A BIT. NEXT IS THE
INCREASING SOUTHERLY WINDS AHEAD OF NEXT WAVE THAT SHOULD GUST TO 30
TO 35 MPH LATER THIS MORNING AND AFTERNOON WHICH SHOULD CREATE AREAS
OF BLOWING SNOW. WILL NOT ISSUE ANY ADVISORY AS HARD TO CREATE
WIDESPREAD BLOWING PROBLEMS WHEN LOW LEVEL MOISTURE INCREASES OVER
FRESH SNOW COVER. SO FOR NOW WILL JUST MENTION AREAS OF BLOWING SNOW
THROUGH THE EVENING HOURS. HIGH TEMPERATURES TODAY WILL AGAIN
STRUGGLE ACROSS THE EAST BUT SHOULD WARM CLOSER TO NORMAL ACROSS THE
WEST.
WITH STOUT SOUTHERLY FLOW TONIGHT...NOT EXPECTING TEMPERATURES TO
FALL MUCH AND SHOULD ACTUALLY RISE A BIT...ESPECIALLY EAST. SYSTEM
COMING OUT LATE TONIGHT AND SUNDAY A BIT SLOWER. STILL CONTINUES TO
SHOW A SPLIT FLOW SYSTEM WITH ONE SYSTEM LIFTING UP ACROSS NORTHWEST
CWA AND SOUTHERN WAVE MOVING NORTHEAST ACROSS CENTRAL PLAINS AND
THEN PHASING EAST OF I29 SUNDAY NIGHT. WITH SLOWER SPEED THERE MAY
NOT BE MUCH IF ANY PRECIPITATION ACROSS WESTERN CWA TONIGHT EXCEPT
POSSIBLY FAR WESTERN CWA AFTER 09Z. WARM ENOUGH ALOFT THAT ANY
PRECIPITATION WOULD BE FREEZING RAIN AND NOT SNOW SO WILL REMOVE
MENTION OF SNOW LATE TONIGHT. AMOUNTS IF ANY WILL BE VERY LIGHT AND
WILL NOT ISSUE ANY HEADLINE.
ON SUNDAY...SOUTHERN WAVE MAY CLIP NORTHWEST IOWA DURING THE
AFTERNOON AND WILL KEEP 40% POPS THERE AND LIKELY POPS ACROSS FAR
NORTHWEST CWA WITH NORTHERN WAVE. IN BETWEEN WILL KEEP POPS
RELATIVELY LOW IN THE 30% RANGE. DOUBT WE WILL SEE ANY FREEZING RAIN
BY LATER SUNDAY MORNING AND AFTERNOON AS AIRMASS COOLS AND ANYTHING
THAT DOES FALL WILL BE SNOW. SO WILL REMOVE ANY MENTION OF RAIN WEST
AND WILL ALSO LOWER HIGH TEMPERATURES DUE TO THE COOLING OF THE
COLUMN WITH THESE FEATURES. COULD SEE AN INCH OR TWO OF SNOW IN THE
JAMES VALLEY SUNDAY AFTERNOON. GUSTY NORTHWEST WINDS WILL DEVELOP
SUNDAY AFTERNOON ACROSS THE WESTERN CWA AS SURFACE TROF MOVES EAST
WITH COLD AIR ADVECTION BRINGING IN STRONGER WINDS. SO COULD SEE
SOME MORE BLOWING SNOW ACROSS THE WEST.
SUNDAY NIGHT WILL SEE GUSTY NORTHWEST WINDS AND AREAS OF BLOWING
SNOW WITH SOME LIGHT SNOW ACROSS THE CWA WITH PHASING UPPER TROF.
NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS WITH LESS THAN ONE
INCH EXPECTED.
ANOTHER CHILLY DAY ON MONDAY BEHIND THE WAVE WITH BELOW NORMAL
TEMPERATURES EAST WITH HIGHS IN THE TEENS TO LOWER 20S. SHOULD BE A
BIT WARMER WEST WITH HIGHS IN THE 20S. SURFACE HIGH WILL SETTLE
ACROSS THE CWA MONDAY NIGHT...AND WITH LIGHT WINDS AND FRESH SNOW
COVER...WITH GO 5 TO 10 DEGREES COLDER THAN CONSALL AND CONSRAW
WHICH ARE NOT HANDLING SNOW COVER WELL AS EVIDENT BY THE VERY COLD
TEMPERATURES THIS MORNING ACROSS MUCH OF CWA. WOULD NOT BE SUPRISED
IF A FEW LOCATIONS ACROSS THE EAST DROP BELOW ZERO EARLY TUESDAY
MORNING.
SHOULD BE WARMER ACROSS THE CWA TUESDAY THROUGH FRIDAY WITH A MORE
ZONAL FLOW...BUT SNOW COVER WILL HAVE A HUGE IMPACT...ESPECIALLY
EAST WHERE SNOW COVER IS DEEPER AND WILL NOT MELT OFF. SO MAY AT
BEST SEE HIGHS NEAR 30 ACROSS THE EAST DURING THIS TIME
PERIOD...WHILE WESTERN CWA WILL HAVE A BETTER CHANCE TO MELT AWAY
SOME OF THE SNOW AND APPROACH 40 FOR DAYTIME HIGHS...ESPECIALLY
SOUTHWEST CWA.
DOESN`T LOOK LIKE MUCH THREAT FOR ANY PRECIPITATION AFTER SUNDAY AND
WILL BASICALLY KEEP CWA DRY EXPECT FOR A VERY SLIGHT CHANCE OF LIGHT
SNOW TUESDAY NIGHT EAST OF I29 WITH VERY WEAK WAVE.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
LAST OF MAINLY OVER FAR SOUTHEAST SOUTH DAKOTA SHOULD EXIT OVER
FIRST FEW HOURS OF TAF PERIOD. VISIBILITIES ARE MORE TRICKY...WITH
POTENTIAL FOR SPOTTY MVFR CONDITIONS THROUGH THE PERIOD. FIRST WILL
BE LATE TONIGHT...AS LIGHT WINDS/CLEAR SKIES/FRESH SNOW COVER ALLOW
FOR STRONG RADIATIVE COOLING. COULD SEE AREAS OF ICE CRYSTALS
DEVELOP IN THE SURFACE RIDGE AXIS...AND HAVE ADDED A FEW HOURS OF
MVFR VISIBILITY TO ALL TAFS DURING PERIOD OF CALM WINDS OVERNIGHT.
SECOND...INCREASING SOUTHERLY WINDS AFTER 15Z-16Z SATURDAY WITH
FREQUENT GUSTS OF 25-30KTS LIKELY...WHICH MAY PRODUCE BLOWING AND
DRIFTING OF THE RELATIVELY FLUFFY FRESH SNOWCOVER. BLOWING SNOW
COULD RESULT IN AREAS OF MVFR OR EVEN SPOTTY IFR VISIBILITY IN OPEN
AREAS DURING THE LATE MORNING/AFTERNOON SATURDAY...AND HAVE MENTION
OF MVFR VISIBILITY IN ALL TAFS DURING PERIOD OF EXPECTED STRONGEST
WIND GUSTS...WHICH COULD APPROACH 35KTS 19Z-23Z. /JH
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1155 AM CST SAT JAN 21 2012
.DISCUSSION...UPDATED FOR 18Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...VARIETY OF FLIGHT RULES XPCTD NEXT 24 HRS. WEAK FRONT
HAS STALLED ACROSS S TX WITH KVCT/KALI REMAINING UNDER STRATUS
DECK WITH IFR CIGS...KCRP IS OVERCAST WITH MVFR...AND KLRD IS AT
VFR. AM XPCTING CLD DECK TO ERODE SOME THIS AFTN WITH VFR/MVFR
DEVELOPING AT TIMES AT KCRP/KVCT/KALI AND VFR PREVAILING AT KLRD.
STRATUS DECK LIKELY TO REDEVELOP AFTER THIS EVENING WITH ALL
TERMINALS XPCTD TO TRANSITION TO MVR/IFR OVERNIGHT AND EVEN LIFR
AT TIMES DUE TO LOW CIGS AND VSBYS. FOG WILL BE POSSIBLE AGAIN BUT
GREATER UNCERTAINTY EXISTS REGARDING TONIGHT/S FOG POTENTIAL AS
COMPARED TO PREVIOUS NIGHTS AND LATER TAF FCSTS MAY NEED TO LOWER
VSBYS FOR AREA TERMINALS. IFR CIGS/VSBYS LIKELY TO PERSIST INTO
SUN MRNG ALL TERMINALS. LIGHT WINDS THIS AFTN FROM N AND E BCMGING
MORE SERLY TONIGHT AND SUN MRNG BUT STILL LIGHT.
&&
.PREV DISCUSSION... /ISSUED 1046 AM CST SAT JAN 21 2012/
DISCUSSION...HAVE LET DENSE FOG ADVISORY EXPIRE AS VISIBILITIES
HAVE IMPROVED. WEAK FRONT AS OF WRITING HAS MOVED THROUGH MOST OF
THE AREA BUT HAS YET TO PUSH ACROSS COASTAL COUNTIES AS MARINE
INFLUENCE IS HELPING STALL PROGRESSION. DRIER AIRMASS HAS FILTERED
INTO NORTHERN ZONES BUT LATEST NAM AND RUC INDICATE SIGNIFICANTLY
DRIER AIR WILL NOT REACH SOUTHERN COUNTIES. HAVE UPDATED SKY
CONDITIONS FOR THIS AFTERNOON AND ALTERED WIND AND TEMPERATURE
DATA TO REFLECT LATEST RUC AND NAM. FORECAST HIGHS ACROSS
NORTHEAST COUNTIES MAY BE A LITTLE GENEROUS BUT WITH CLEARING
SKIES AND DRY AIR WORKING IN TEMPS SHOULD BEGIN TO RISE SOON.
WILL ALSO CONTINUE TO MONITOR MARINE CONDITIONS THROUGH THE DAY
WHERE SEA FOG MAY DEVELOP AT TIMES...POSSIBLY BECOMING LOCALLY
DENSE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 75 58 79 55 71 / 10 10 10 10 10
VICTORIA 70 53 76 50 71 / 10 10 10 10 10
LAREDO 79 61 83 54 77 / 0 0 10 10 10
ALICE 78 58 82 55 74 / 0 10 10 10 10
ROCKPORT 69 58 75 56 66 / 10 10 10 10 10
COTULLA 76 53 81 48 74 / 0 0 10 10 10
KINGSVILLE 79 58 81 56 73 / 0 10 10 10 10
NAVY CORPUS 72 58 75 58 67 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AVIATION...HART/79
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1046 AM CST SAT JAN 21 2012
.DISCUSSION...HAVE LET DENSE FOG ADVISORY EXPIRE AS VISIBILITIES
HAVE IMPROVED. WEAK FRONT AS OF WRITING HAS MOVED THROUGH MOST OF
THE AREA BUT HAS YET TO PUSH ACROSS COASTAL COUNTIES AS MARINE
INFLUENCE IS HELPING STALL PROGRESSION. DRIER AIRMASS HAS FILTERED
INTO NORTHERN ZONES BUT LATEST NAM AND RUC INDICATE SIGNIFICANTLY
DRIER AIR WILL NOT REACH SOUTHERN COUNTIES. HAVE UPDATED SKY
CONDITIONS FOR THIS AFTERNOON AND ALTERED WIND AND TEMPERATURE
DATA TO REFLECT LATEST RUC AND NAM. FORECAST HIGHS ACROSS
NORTHEAST COUNTIES MAY BE A LITTLE GENEROUS BUT WITH CLEARING
SKIES AND DRY AIR WORKING IN TEMPS SHOULD BEGIN TO RISE SOON.
WILL ALSO CONTINUE TO MONITOR MARINE CONDITIONS THROUGH THE DAY
WHERE SEA FOG MAY DEVELOP AT TIMES...POSSIBLY BECOMING LOCALLY
DENSE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 75 58 79 55 71 / 10 10 10 10 10
VICTORIA 70 53 76 50 71 / 10 10 10 10 10
LAREDO 79 61 83 54 77 / 0 0 10 10 10
ALICE 78 58 82 55 74 / 0 10 10 10 10
ROCKPORT 69 58 75 56 66 / 10 10 10 10 10
COTULLA 76 53 81 48 74 / 0 0 10 10 10
KINGSVILLE 79 58 81 56 73 / 0 10 10 10 10
NAVY CORPUS 72 58 75 58 67 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
UPDATE...HART/79
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
319 PM CST SAT JAN 21 2012
.SHORT TERM...TONIGHT THROUGH MONDAY
319 PM CST SAT JAN 21 2012
MAIN FOCUS IS ON A VARIETY OF PRECIPITATION TYPES FOR LATER TONIGHT
THROUGH MONDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED TROUGHING OVER THE WESTERN U.S....RIDGING ACROSS MUCH OF THE
PLAINS...AND TROUGHING OVER SOUTHEAST CANADA. 500MB HEIGHT FALLS IN
12 HOURS ARE AS MUCH AS 170 METERS WITH THE WESTERN TROUGH ACCORDING
TO THE RUC...CENTERED OVER EASTERN NEVADA. THE FORECAST AREA RESIDES
ON THE EAST SIDE OF THE RIDGING...FAVORING HIGH PRESSURE AT THE
SURFACE. THIS HIGH WAS CENTERED OVER LAKE MICHIGAN...AFTER BEING
OVER THE FORECAST AREA EARLY THIS MORNING WHICH ALLOWED FOR THE 10
TO 20 BELOW ZERO READINGS. SOUTHERLY FLOW IS INCREASING ON THE BACK
SIDE OF THE HIGH...ESPECIALLY ACROSS THE PLAINS AHEAD OF A LEE
TROUGH. 850MB PROFILER AND RUC WIND DATA SHOWED SOUTHWEST WINDS OF
35-50 KT FROM KANSAS INTO THE EASTERN DAKOTAS AND WESTERN MINNESOTA.
SOUNDINGS SHOW SOME STRONG WARMING AT 850MB AS A RESULT OF THE
INCREASING WINDS. BETWEEN 00Z AND 12Z...850MB TEMPS ROSE FROM -11C
TO -2C AT OAX...-11C TO +2C AT LBF AND -14C TO +6C AT UNR. THE
SOUTHERLY FLOW IS ALSO ADVECTING STRATUS THAT WAS JUST SOUTH OF THE
FORECAST AREA THIS MORNING BACK TO THE NORTHWEST. THE STRATUS DECK
NOW COVERS MUCH OF IOWA AND THE WESTERN HALF OF MINNESOTA. LAST ITEM
OF NOTE IS A LARGE AREA OF STRATUS ALONG THE GULF COAST...AS WELL AS
HIGHER SURFACE DEWPOINTS. THIS MOISTURE IS IMPORTANT FOR TOMORROW.
MODEL ANALYSIS...MODELS ARE STILL HAVING SOME ISSUES WITH THE
TROUGHING OVER THE WESTERN U.S. AS IT TRACKS INTO THE PLAINS ON
SUNDAY. THE GFS/ECMWF/CANADIAN ARE BY FAR THE DEEPEST... ESPECIALLY
WHEN IT COMES TO THE SHORTWAVE AT THE BASE OF THE TROUGH WHICH
CROSSES THE SOUTHERN PLAINS. THE ECMWF HAS BEEN EXTREMELY CONSISTENT
WITH THE GFS AND CANADIAN TRENDING RAPIDLY TOWARDS THE ECMWF. AS
SUCH...THESE MODELS ALLOW FOR THAT SHORTWAVE TO TURN NEGATIVE TILT
AND LIFT INTO ILLINOIS SUNDAY NIGHT. IMMEDIATELY AHEAD OF THIS
SHORTWAVE THERE IS A DEEPENING SURFACE LOW...WHICH ENDS UP TRACKING
FROM OKLAHOMA ON SUNDAY TO NEAR MILWAUKEE AT 12Z MONDAY. THE 21.12Z
NAM CONTINUES TO SUGGEST A LITTLE MORE PROGRESSIVE TROUGH AND LESS
FOCUS ON THE NEGATIVELY TILT SHORTWAVE...RESULTING IN THE SURFACE
LOW TRACKING FROM SOUTH DAKOTA ON SUNDAY TO THUNDER BAY ONTARIO BY
12Z MONDAY. BASED ON HOW POTENT THE TROUGH LOOKS CROSSING NEVADA
THIS AFTERNOON...NOTED TOO BY THE LIGHTNING ASSOCIATED WITH IT...
THINK THE DEEPER GFS/ECMWF SCENARIOS ARE MORE LIKELY TO OCCUR.
TONIGHT...LOW LEVEL SOUTHERLY FLOW WILL INCREASE TONIGHT AS THE
WESTERN U.S. TROUGH BEGINS TO MOVE INTO THE WESTERN SIDE OF THE
PLAINS. AS THIS SOUTHERLY FLOW INCREASES...THE STRATUS TO OUR SOUTH
AND WEST WILL GRADUALLY OVERSPREAD THE FORECAST AREA...TAKING THE
LONGEST OVER WISCONSIN. IN ADDITION...TEMPERATURES AND DEWPOINTS
SHOULD RISE AS THE WARMER READINGS TO THE SOUTH ADVECT NORTHWARD.
A BIG CONCERN IS SOME OF THE FLURRY ACTIVITY THAT HAS ALREADY
OCCURRED IN THE STRATUS DECK. THERE ARE INDICATIONS THAT THE LIFT
PRODUCING THESE FLURRIES WILL OCCUR AT LEAST OVER NORTHWEST SECTIONS
OF THE FORECAST AREA AFTER MIDNIGHT...AND PERHAPS WESTERN SECTIONS
TOO. HOWEVER...AS THE TEMPERATURES IN THE STRATUS DECK
WARM...WORRIED THAT WE MAY LOSE ICE PRODUCTION...RESULTING IN
FREEZING DRIZZLE. PLACED BOTH A MENTION OF FLURRIES AND PATCHY
FREEZING DRIZZLE AFTER MIDNIGHT OVER NORTHWEST SECTIONS.
SUNDAY...STRONG SOUTHERLY FLOW LOOKS TO CONTINUE WITH THE AREA STILL
AHEAD OF THE UPPER TROUGH MOVING INTO THE PLAINS...AS WELL AS THE
ASSOCIATED SURFACE TROUGH/LOW. THIS SOUTH FLOW SHOULD BRING THE
WARMER AND MORE MOIST AIR ALONG THE GULF COAST NORTHWARD INTO THE
FORECAST AREA. AS A RESULT...THE STRATUS DECK OVER THE FORECAST AREA
SHOULD DEEPEN THROUGH THE DAY. WITH THE STRATUS DECK WARMER THAN
-10C OVER MUCH OF THE AREA THROUGH THE ENTIRE DAY...ENVISIONING ONLY
DRIZZLE. THERE ARE INDICATIONS OF MID AND UPPER LEVEL CLOUDS COMING
ACROSS...WITH LIFT THERE TOO TO PRODUCE ICE...BUT THE DRY LAYER
BETWEEN THESE CLOUDS AND THE LOW STRATUS IS DEEPER AND DRIER THAN
PROGGED TWO DAYS AGO. THEREFORE...ANY ICE PRODUCED ALOFT SHOULD
EVAPORATE BEFORE REACHING THE STRATUS. EVEN IF IT DID REACH THE
STRATUS...THE DRY LAYER HAS TEMPERATURES PROGGED AT 3-6C WHICH WOULD
TEND TO MELT THE ICE. LIFT WITHIN THE STRATUS DECK IS PROGGED TO
INCREASE TOO THROUGH THE DAY...NOTED ON 280-285K SURFACES...WHICH
MAY RESULT IN A CHANGE FROM DRIZZLE TO RAIN. HOWEVER...NONE OF THE
LIFT IS ALL THAT STRONG...SO KEPT THINGS SIMPLE AND STATED DRIZZLE
ALL DAY. QPF/ICE AMOUNTS LIKELY TO BE ONE TO THREE HUNDREDTHS. WHERE
FREEZING DRIZZLE AND DRIZZLE OCCURS WILL BE DICTATED BY SURFACE
TEMPERATURE...TO SOME DEGREE. ONE ISSUE IS THAT WE HAVE HAD A LOT OF
COLD TEMPERATURES RECENTLY...SO EVEN WHERE TEMPERATURES CLIMB ABOVE
FREEZING...UNTREATED SURFACES MAY ICE UP. KEPT PRECIPITATION CHANCES
LOW SINCE THERE STILL IS UNCERTAINTY ON HOW MUCH DRIZZLE WILL FALL.
MOS GUIDANCE QUITE LOW ON NUMBERS...THOUGH 21.15Z SREF DOES INDICATE
60-70 PERCENT OF MEMBERS PRODUCING A 0.01 OR MORE OF QPF. WITH
PRECIPITATION CHANCES RIGHT NOW FORECAST AT BELOW 60 PERCENT...AND
PER COLLABORATION WITH SURROUNDING OFFICES...HELD OFF ON ANY
FREEZING RAIN ADVISORY FOR NOW. DO FEEL THAT AN ADVISORY WILL BE
NEEDED.
SUNDAY NIGHT INTO MONDAY...AS THE LOW DEEPENS AND LIFTS OFF TO THE
NORTHEAST SUNDAY NIGHT...COLDER AIR WILL GRADUALLY FILTER SOUTHEAST
INTO THE FORECAST AREA FROM THE NORTHERN PLAINS. HOW FAST THIS
OCCURS DEPENDS ON THE EXACT TRACK OF THE LOW...WHICH IS STILL FAR
FROM CERTAIN. THEREFORE...POTENTIAL REMAINS FOR DRIZZLE/FREEZING
RAIN UNTIL THE LOW PASSES. EVEN THEN...DEPENDING ON THE LOW
TRACK...THERE COULD STILL BE A WARM LAYER ALOFT THAT HAS TO COOL..
RESULTING IN MIXED PRECIPITATION TYPES. FOR NOW...JUST STUCK WITH A
DRIZZLE/FREEZING DRIZZLE EVENING CHANGING OVER TO RAIN/SNOW AFTER
MIDNIGHT. NEEDLESS TO SAY MORE MODIFICATION WILL BE NEEDED FOR
SUNDAY NIGHT...POSSIBLY INTO EARLY MONDAY AS WELL. SNOW SHOULD
SLOWLY TAPER OFF SOUTHWEST TO NORTHEAST MONDAY AS THE LOW PULLS AWAY
FROM THE AREA. DID RAISE PRECIPITATION CHANCES MONDAY
MORNING...THOUGH...WITH GOOD CONSENSUS OF WRAP AROUND PRECIPITATION
IN THE AREA. SHOULD SEE TEMPERATURES CLIMB SOME SUNDAY NIGHT AS THE
LOW APPROACHES...THEN SLOWLY FALL ON MONDAY AS THE LOW MOVES AWAY.
WINDS SHOULD PICK UP TOO ON MONDAY...ESPECIALLY OVER THE WIND
FAVORED AREAS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. LOOKS LIKE
WINDS SHOULD STAY WELL BELOW ADVISORY...THOUGH.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
319 PM CST SAT JAN 21 2012
AFTER AN ACTIVE SHORT TERM PERIOD...LONG TERM FORECAST AT LEAST AT
THIS TIME LOOKS FAIRLY BENIGN. IN THE MEAN...ALL MODELS ARE IN
AGREEMENT OF A FAST WEST-NORTHWEST PATTERN FROM THE PACIFIC
NORTHWEST INTO OUR REGION...WHICH MAY BECOME A LITTLE MORE
NORTHWESTERLY ON SATURDAY WITH INDICATIONS OF A SHORTWAVE TROUGH
DIGGING DOWN INTO THE FORECAST AREA. THIS PATTERN WILL SUPPORT A
FLOW OF MILD PACIFIC AIR INTO THE FORECAST AREA...NOTED BY 850MB
TEMPS THAT STRUGGLE TO GET COLDER THAN -6C FOR THE MOST PART UNTIL
SATURDAY. THERE ARE A FEW SHORTWAVE TROUGHS PROGGED TO MOVE THROUGH
THE AREA...ONE TUESDAY NIGHT AND WEDNESDAY...AND ANOTHER ON
THURSDAY. NEITHER OF THESE FEATURES PRODUCE MUCH QPF IN MODEL
OUTPUT...PRIMARILY BECAUSE THEY DO NOT HAVE MUCH MOISTURE TO WORK
WITH. THE SYSTEM IN THE SHORT TERM PERIOD PRETTY MUCH SHUNTS ALL
MOISTURE SOUTH AND EAST OF THE AREA. THEREFORE...ONLY SOME SLIGHT
CHANCES REMAIN FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
PRECIPITATION TYPE MAY HAVE TO BE WATCHED FOR THIS TIME
PERIOD...GIVEN THE MILDER 850MB TEMPS. WOULD NOT BE SURPRISED TO SEE
EITHER MIXES WITH RAIN...OR WORSE A LOSS OF ICE RESULTING IN
RAIN/FREEZING RAIN VERSUS SNOW. KEPT PRECIPITATION TYPES AS SNOW
SINCE BOTH DETAILS ARE VERY UNCERTAIN AT THIS TIME.
FOR MUCH OF THE LONG TERM PERIOD...FOLLOWED A CONSENSUS BLEND OF
GUIDANCE FOR BOTH TEMPERATURES AND PRECIPITATION THROUGHOUT THE
LONG TERM PERIOD.
&&
.AVIATION...THROUGH 18Z SUNDAY
1137 AM CST SAT JAN 21 2012
FIRST ISSUE TO CONTEND WITH IS THE LOW CLOUDS ON THE EDGE OF THE
SURFACE RIDGE AXIS AND HOW FAST THEY POSSIBLY RETURN TO THE AREA.
BOTH THE 21.12Z NAM AND 21.15Z RUC SHOW THIS LOW LEVEL MOISTURE
SURGING NORTH INTO WESTERN AND CENTRAL MINNESOTA DURING THE
EVENING. AT THE SAME TIME...A POCKET OF DRY AIR...CURRENTLY OVER
NORTHERN INDIANA AND EASTERN ILLINOIS...GETS PULLED NORTH INTO
WISCONSIN. BOTH MODELS ARE REMARKABLY SIMILAR IN SHOWING THE
MOISTURE AND LOW CLOUDS RETURNING TO KRST THIS EVENING AROUND 03Z
WITH THE DRY AIR HOLDING ON AT KLSE WELL INTO THE NIGHT. THUS DID
NOT RETURN THE LOW CLOUDS TO KLSE UNTIL 08Z. THE NEXT ISSUE IS
WHEN AND IF THERE WILL BE ANY PRECIPITATION ONCE THE LOW CLOUDS
MOVE IN. AGAIN THE NAM AND RUC ARE IN GOOD AGREEMENT IN SHOWING
THE WARM AIR ADVECTION AND OMEGA IN THE 0-2KM LAYER TO BE
MAXIMIZED TONIGHT NORTH OF BOTH TAF SITES SO DID NOT INITIALLY ADD
ANY PRECIPITATION WITH THE RETURN OF THE LOW CLOUDS. LOOKING AT
THE BUFKIT SOUNDINGS...IT LOOKS LIKE IT WILL TAKE UNTIL SUNDAY
MORNING BEFORE THE DEPTH OF THE SATURATED LAYER AND THE OMEGA
THROUGH IT BECOME SUFFICIENT TO SUPPORT ANY PRECIPITATION. ONCE
THIS OCCURS...THE PRECIPITATION SHOULD BE FREEZING DRIZZLE AS THE
DEPTH OF SATURATION IS NOT ENOUGH TO SUPPORT ANY ICE IN THE
CLOUDS. HAVE THUS ADDED THIS TO BOTH TAF SITES IN THE 14 TO 15Z
TIME FRAME. THE FINAL THING TO CONTEND WITH IS THE POSSIBILITY OF
LOW LEVEL WIND SHEAR OVERNIGHT. AS THE LOW LEVEL RIDGE AXIS MOVES
OFF TONIGHT AND STRONG LOW LEVEL LOW PRESSURE BEGINS TO TAKE SHAPE
EAST OF THE ROCKIES...THE LOW LEVEL WINDS ARE EXPECTED TO INCREASE
RAPIDLY ABOVE THE SURFACE INVERSION. WINDS AT 2000 FEET ARE
EXPECTED TO INCREASE TO THE 35 TO 45 KNOT RANGE THIS EVENING AND
EVEN POSSIBLY INCREASE SOME OVERNIGHT. THIS WILL CREATE ABOUT A 25
KNOT DIFFERENCE IN SPEEDS WITH SOME SLIGHT CHANGE IN WIND DIRECTION
AND HAVE INCLUDED WIND SHEAR AT BOTH TAF SITES UNTIL THE INVERSION
IS EXPECTED TO START WEAKENING SUNDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 PM CST SAT JAN 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 AM CST SAT JAN 21 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
230 AM CST SAT JAN 21 2012
PROBLEMATIC FORECAST FOR SUNDAY-SUNDAY NIGHT AS A COMPLEX SCENARIO
BRINGS THE THREAT FOR A WINTERY MIX.
A 500 MB TROUGH STILL SET TO MOVE EAST OUT OF THE ROCKIES...THEN
NORTHEAST ACROSS THE GREAT LAKES BY 12Z MON. MODEL DIFFERENCES
CONTINUE...WITH THE 21.00Z NAM REMAINING THE QUICKER MODEL. IT MOVES
ITS ASSOCIATED SFC LOW OVER LAKE SUPERIOR BY 06Z MON WHILE THE GFS
WOULD SLIDE ITS LOW OVER SOUTHERN WI BY THIS TIME. MEANWHILE...THE
EC CONTINUES TO BE THE SLOWER MODEL...HOLDING ITS SFC LOW BACK OVER
NORTHERN MO...NOT MOVING IT INTO SOUTHEAST WI UNTIL 12Z MON. THE
21.00Z GEM IS CLOSE TO THE EC...WITH THE GFS SEEMING TO BE TRENDING
MORE TOWARD THIS SLOWER SOLUTION. THE NAM IS THE ODD MODEL OUT AND
WILL CRAFT THE FORECAST TOWARD A GFS/EC BLEND.
WHILE THE BRUNT OF THE UPPER LEVEL FORCING WON/T SHIFT ACROSS THE
REGION UNTIL SUNDAY NIGHT...THERE IS SOME LOW LEVEL WARM AIR
ADVECTION AND A BIT OF ISENTROPIC UPGLIDE TO CONTEND WITH.
NORTHWEST-SOUTHEAST RUNNING X-SECTIONS/BUFKIT SOUNDINGS SHOW AN
INCREASE IN THE NEAR SFC SATURATION...BUT ONLY TO ABOUT 850 MB BY
THE AFTERNOON. WITH A GOOD AMOUNT OF WARMING IN THE 925-850 MB
LAYER...THERE WILL BE NO ICE IN THE CLOUD...AND ANY PCPN GENERATED
FROM THE THERMODYNAMICS WOULD BE LIQUID/FREEZING - DEPENDING ON SFC
TEMPS. PROBABLY MORE A DRIZZLE THREAT IN THE MORNING...AND DEEPENING
SATURATION IN THE AFTERNOON MAKING RAIN A BIT MORE LIKELY...IF
ANYTHING WOULD OCCUR. TO MAKE IT LESS COMPLEX...WILL STAY WITH
RAIN/FREEZING RAIN WORDING FOR NOW. THE GFS AND GEM BOTH PRODUCE
SOME LIGHT QPF ON SUNDAY...AND IF THIS MANIFESTS...SOME ICY SPOTS
WOULD DEVELOP WHERE SFC TEMPS ALLOWED. ON THE PLUS SIDE...IT DOES
LOOK LIKE A GOOD PORTION OF THE FORECAST AREA WOULD WARM ABOVE
FREEZING SUNDAY AFTERNOON. THAT SAID...EXPOSED SFCS COULD STILL
ALLOW FOR FREEZING THANKS TO THE RECENT BOUT OF COLD DAYS.
THE SATURATION DEEPENS SUN EVENING...AND THAT WILL RESULT IN A
CHANGE OVER TO SNOW AS ICE IS INTRODUCED INTO THE CLOUD. THIS CHANGE
OVER WILL COINCIDE WITH THE SHORTWAVE MOVING IN...ALONG WITH
STRONGER 700-300 MB QG CONVERGENCE AND SOME FRONTOGENETIC FORCING IN
THE 700-500 MB LAYER. MUCH OF THE EVENING COULD STILL SEE MORE OF A
RAIN/FREEZING RAIN THREAT THOUGH.
THE LOW PRESSURE SYSTEM WILL EXIT INTO SOUTHEAST CANADA MON
EVENING...AND DROP A COUPLE INCHES OF SNOW ACCUMULATION TO NORTHERN
PORTIONS OF THE FORECAST BY THE TIME IT EXITS. ALL IN ALL
THOUGH...THE MIXED PCPN AND THREAT FOR FREEZING RAIN/FREEZING
DRIZZLE APPEARS TO BE THE MAIN CONCERN WITH THIS WEATHER SYSTEM. ITS
EVOLUTION WILL BE MONITORED CLOSELY.
ASIDE FROM THE MIXED BAG OF WINTER WEATHER...THE LOW WILL ALSO USHER
IN A COUPLE WINDY DAYS. SOUTH WINDS WILL PICK UP TONIGHT AND PERSIST
FOR THE EARLY PART OF SUNDAY...AND WILL BE RATHER BLUSTERY AT TIMES.
INCREASING PRESSURE GRADIENT ON THE BACKSIDE OF THE DEPARTING LOW
WILL RESULT IN BLUSTERY NORTHWEST WINDS FOR MONDAY. WHILE WARMER AIR
RETURNS WITH THE SOUTHERLY FETCH...COLD AIR WILL FOLLOW WITH THE
NORTHWEST WINDS...AND HIGHS MONDAY WILL LIKELY OCCUR EARLY IN THE
DAY - STEADY TO SLOWLY FALLING FOR THE REST OF THE DAY.
.LONG TERM...TUESDAY THROUGH FRIDAY
230 AM CST SAT JAN 21 2012
THE GFS AND EC FAVOR SLIDING A SHORTWAVE TROUGH THROUGH A SFC HIGH
TUE NIGHT...BUT ACROSS NORTHERN PORTIONS OF THE REGION. CURRENT
TRACK WOULD APPEAR TO HAVE MINIMAL IMPACT ON THE LOCAL AREA. THE EC
THEN BRINGS A SHARPER/STRONGER UPPER LEVEL TROUGH OVER THE UPPER
MISSISSIPPI RIVER VALLEY FOR WED NIGHT/THU. IT WILL HAVE TO BRING
ITS OWN MOISTURE AND CURRENT QPF VIA THE EC KEEPS THE BETTER PCPN
CHANCES OVER NORTHERN/EASTERN WI. MEANWHILE...THE GFS IS BASICALLY
DRY AS IT HAS ONLY A RIPPLE MOVING NORTH OF THE REGION. THE GEM IS
MORE LIKE THE EC...WHILE THE EC HAS BEEN A BIT MORE CONSISTENT
WITHIN ITSELF COMPARED TO THE GFS. WILL LEAN ON THE
EC/GEM/CONSENSUS FOR DETAILS IN THIS PERIOD. THE MOSTLY ZONAL FLOW
A LOFT LOOKS FAIRLY ACTIVE NEXT WEEK WITH THE MODELS THEN SUGGESTING
ANOTHER SHORTWAVE TROUGH ON EITHER THU-FRI...DEPENDING ON WHICH
MODEL YOU PREFER. THE GFS IS QUICKER THAN THE EC...AND WILL AGAIN
SIDE WITH EC/CONSENSUS FOR NOW. STILL...IT LOOKS LIKE THE
BETTER PCPN CHANCES MAY HOLD NORTH OF THE FORECAST AREA.
&&
.AVIATION...THROUGH 18Z SUNDAY
1137 AM CST SAT JAN 21 2012
FIRST ISSUE TO CONTEND WITH IS THE LOW CLOUDS ON THE EDGE OF THE
SURFACE RIDGE AXIS AND HOW FAST THEY POSSIBLY RETURN TO THE AREA.
BOTH THE 21.12Z NAM AND 21.15Z RUC SHOW THIS LOW LEVEL MOISTURE
SURGING NORTH INTO WESTERN AND CENTRAL MINNESOTA DURING THE
EVENING. AT THE SAME TIME...A POCKET OF DRY AIR...CURRENTLY OVER
NORTHERN INDIANA AND EASTERN ILLINOIS...GETS PULLED NORTH INTO
WISCONSIN. BOTH MODELS ARE REMARKABLY SIMILAR IN SHOWING THE
MOISTURE AND LOW CLOUDS RETURNING TO KRST THIS EVENING AROUND 03Z
WITH THE DRY AIR HOLDING ON AT KLSE WELL INTO THE NIGHT. THUS DID
NOT RETURN THE LOW CLOUDS TO KLSE UNTIL 08Z. THE NEXT ISSUE IS
WHEN AND IF THERE WILL BE ANY PRECIPITATION ONCE THE LOW CLOUDS
MOVE IN. AGAIN THE NAM AND RUC ARE IN GOOD AGREEMENT IN SHOWING
THE WARM AIR ADVECTION AND OMEGA IN THE 0-2KM LAYER TO BE
MAXIMIZED TONIGHT NORTH OF BOTH TAF SITES SO DID NOT INITIALLY ADD
ANY PRECIPITATION WITH THE RETURN OF THE LOW CLOUDS. LOOKING AT
THE BUFKIT SOUNDINGS...IT LOOKS LIKE IT WILL TAKE UNTIL SUNDAY
MORNING BEFORE THE DEPTH OF THE SATURATED LAYER AND THE OMEGA
THROUGH IT BECOME SUFFICIENT TO SUPPORT ANY PRECIPITATION. ONCE
THIS OCCURS...THE PRECIPITATION SHOULD BE FREEZING DRIZZLE AS THE
DEPTH OF SATURATION IS NOT ENOUGH TO SUPPORT ANY ICE IN THE
CLOUDS. HAVE THUS ADDED THIS TO BOTH TAF SITES IN THE 14 TO 15Z
TIME FRAME. THE FINAL THING TO CONTEND WITH IS THE POSSIBILITY OF
LOW LEVEL WIND SHEAR OVERNIGHT. AS THE LOW LEVEL RIDGE AXIS MOVES
OFF TONIGHT AND STRONG LOW LEVEL LOW PRESSURE BEGINS TO TAKE SHAPE
EAST OF THE ROCKIES...THE LOW LEVEL WINDS ARE EXPECTED TO INCREASE
RAPIDLY ABOVE THE SURFACE INVERSION. WINDS AT 2000 FEET ARE
EXPECTED TO INCREASE TO THE 35 TO 45 KNOT RANGE THIS EVENING AND
EVEN POSSIBLY INCREASE SOME OVERNIGHT. THIS WILL CREATE ABOUT A 25
KNOT DIFFERENCE IN SPEEDS WITH SOME SLIGHT CHANGE IN WIND DIRECTION
AND HAVE INCLUDED WIND SHEAR AT BOTH TAF SITES UNTIL THE INVERSION
IS EXPECTED TO START WEAKENING SUNDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 AM CST SAT JAN 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1116 AM CST SAT JAN 21 2012
.AVIATION/18Z TAFS/...VFR SKC FOR MUCH OF THE CWA INTO THE EVENING
HOURS. ONLY CONCERN AREA IS FROM NEAR KMKE SOUTH TO KENW WHERE
LAKE EFFECT MVFR CLOUDS WILL SKIRT THIS AREA. LOW LEVEL RH PROGS
HAVE A PRETTY GOOD HANDLE ON LOCATION OF STRATUS FIELD TO OUR
SOUTH AND SOUTHWEST. THIS WILL START COMING BACK LATER TONIGHT
INTO SUNDAY AS FLOW TURNS MORE SOUTHERLY. BUFKIT SOUNDINGS SHOW
CONSIDERABLE MOISTENING IN THE LOW LAYERS...SO WHILE THE INCREASE
WILL INITIALLY BE MVFR...AS MOISTURE INCREASES...WILL SEE IFR AND
SOME LIFR TAKING SHAPE AS WELL. WILL HOLD OFF ON ANY MENTION OF
DZ/FZDZ IN THE TAFS THROUGH 18Z. BETTER POTENTIAL AFTER 18Z...BUT
CONFIDENCE LOW AT THIS POINT. TEMPS PROGGD IN MANY AREAS TO RISE
ABOVE FREEZING MARK BY ONSET TIME...ESPECIALLY IN EASTERN WI.
PC
&&
.PREV DISCUSSION... /ISSUED 317 AM CST SAT JAN 21 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
NEAR LAKE MICHIGAN THE MAIN ISSUE WILL BE HANDLING LAKE EFFECT
TRENDS. NORTHEAST WINDS IN SHALLOW LAYER FROM 975 MB TO 900 MB.
LAPSE RATES ARE NOT TO STEEP WITH AROUND 3 C/KM AT MILWAUKEE BUT
NEAR 6C/KM NEAR KENOSHA AT 09Z BUT LAPSE RATES INCREASE TO NEAR
9C/KM AT 18Z WITH INVERSION HEIGHT AROUND 3 THSD FT. LOW LEVEL FLOW
WEAKENS AND BECOMES MORE EAST. THEREFORE EXPECT THE SNOW BAND NEAR
KENOSHA TO CONTINUE TO WEAKEN AND THEN EVENTUALLY BECOME MORE
DIFFUSE WITH GENERAL LIGHT SNOW/FLURRIES NEAR THE LAKE. HRRR SHOWS
THE LAKE BAND PUSHING SOUTH THEN WEAKENING BUT INCREASING IN
COVERAGE. NAM SHOWS SOMETHING SIMILAR.
ELSEWHERE MOISTURE TRAPPED BLOW DEVELOPING INVERSION AROUND
3 THSD FT SHOULD SLOW ANY CLEARING FROM THE WEST. FORECAST
SOUNDINGS SHOW SOME CLEARING POTENTIAL OVER THE FRINGES OF THE
STRATUS SHIELD BUT THEN WITH THE EAST FLOW...LOW LEVELS MOISTEN SO
STRATUS/STRATOCUMULUS COULD EXPAND AGAIN.
MID LEVEL SHORTWAVE OVER THE EASTERN GREAT LAKES EXITS TO THE EAST
WITH MID LEVEL DRYING.
STRONG SHORTWAVE OVER THE PACIFIC NORTHWEST WILL REACH THE ROCKIES
TONIGHT. LOW/MID LEVEL WARM AIR ADVECTION BEGINS BUT THE 850 TO 700
MB LAYER IS FAIRLY DRY SO NOT EXPECTING ANY PRECIPITATION. BY
MIDNIGHT SOUNDINGS SHOW TEMPERATURES AROUND 800 MB ALREADY WARMING
ABOVE 0 CELSIUS OVER MUCH OF THE FORECAST AREA...AND ABOVE 0 C BY
SUNRISE. NAM SHOWS SATURATION BELOW 925 MB BUT DOES NOT APPEAR DEEP
ENOUGH MOIST LAYER FOR FREEZING DRIZZLE.
SUNDAY AND MONDAY...FORECAST CONFIDENCE...MEDIUM
MODELS SLOWLY COMING INTO BETTER AGREEMENT FOR THE SUNDAY/MONDAY LOW
PRESSURE SYSTEM. THE GFS HAS TRENDED TOWARD THE SLOWER ECMWF AND
CANADIAN SOLUTIONS...WHILE THE NAM REMAINS THE QUICKEST. LEANED
FORECAST PRETTY HEAVILY TOWARD CONSISTENT ECMWF.
OVERALL...LOOKS LIKE A CHANCE FOR WARM ADVECTION PRECIP ON SUNDAY.
MID LEVELS ARE QUITE DRY IN SOUNDINGS...WITH VERY LITTLE ICE
EXPECTED. WITH SFC TEMPS BELOW FREEZING TO START THE DAY...KEPT
MENTION OF FREEZING RAIN. MENTIONED RAIN A CHANCE FOR RAIN AS WELL
IN THE AFTERNOON AS TEMPS WARM ABOVE FREEZING. ONLY REASON SNOW WAS
LEFT IN FOR SUNDAY IS THAT SOME MODELS DO SHOW SOME ICE CRYSTAL
POTENTIAL ABOVE THE DRY LAYER. DRY LAYER LOOKS LIKE IT WILL
GENERALLY DRY UP ANY ICE...BUT POTENTIAL FOR SEEDING IS THERE IF DRY
LAYER IS OVERDONE IN MODELS.
PRECIP AMOUNTS EXPECTED TO BE LIGHT DURING THE DAY SUNDAY...SO ANY
ICING WOULD BE FAIRLY LIMITED.
SFC LOW EXPECTED TO MOVE THROUGH SUNDAY NIGHT...ALONG WITH BEST SHOT
FOR PRECIP FROM THIS STORM. ENOUGH OVERLAP BETWEEN MODELS TO BUMP
POPS UP TO CATEGORICAL. LOOKS LIKE MAINLY RAIN EAST...MIXING WITH
SNOW WEST. MAY SEE EVENTUAL CHANGE OVER TO SNOW WEST TO EAST
BEGINNING LATE SUNDAY NIGHT OR MONDAY MORNING...WITH SOME LIGHT
ACCUMULATIONS POSSIBLE.
WITH DEWPOINTS EXPECTED TO GET INTO THE MID 30S OVER THE
SNOWPACK...AND THE SFC LOW COMING RIGHT OVERHEAD...MENTIONED PATCHY
FOG IN THE EAST SUN NIGHT AND MON MORNING.
TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
LOOKS FAIRLY QUIET TUESDAY THROUGH THE REMAINDER OF THE WORK WEEK.
MODELS DEPICTING A SERIES OF WEAK SHORTWAVES TO ROLL THROUGH DURING
THIS PERIOD...POSSIBLY BRINGING SOME FLURRIES OR LIGHT SNOW AT
TIMES. NEAR NORMAL TEMPS TUESDAY EXPECTED TO WARM TO A FEW DEGREES
ABOVE NORMAL FOR WEDNESDAY THROUGH FRIDAY.
AVIATION/12Z TAFS/...
MAINLY MVFR CIGS OVER FAR SOUTH CENTRAL AND PORTIONS OF SOUTHEAST
WISCONSIN. LAKE BAND PUSHING SOUTH BUT STRONGEST RADAR RETURNS HAVE
BEEN STAYING OFF SHORE. AS LOW LEVEL FLOW BECOMES MORE EAST LAKE
EFFECT WILL EXPAND IN COVERAGE BUT SHOULD BE FAIRLY LIGHT...ALTHOUGH
SOME AREAS COULD SEE SOME VERY LIGHT ACCUMULATIONS. CIGS/VSBYS WILL
BE MAINLY MVFR.
THE LOW CLOUD SHIELD MAY ERODE SOMEWHAT FROM THE WEST...BUT THEN
WOULD TEND TO EXPAND AGAIN AS EAST FLOW INCREASES THE LOW LEVEL
MOISTURE.
IFR POTENTIAL LATER TONIGHT AS EAST/SOUTHEAST FLOW INCREASES.
MARINE...
A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED LATE TONIGHT THROUGH
MONDAY NIGHT AS LOW PRESSURE MOVES EAST AND EXITS THE NORTHERN
PLAINS. BRISK SOUTH WINDS AND HIGH WAVES WILL PREVAIL SATURDAY
NIGHT INTO SUNDAY NIGHT. A COLD FRONT WILL THEN SHIFT THE WINDS TO
THE WEST FOR LATE SUNDAY NIGHT AND INTO MONDAY NIGHT. THE WINDS
WILL CONTINUE TO BE BRISK AND GUSTY AND SMALL CRAFT CONDITIONS
WILL LIKELY PERSIST FOR THIS TIME PERIOD.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SUNDAY THROUGH FRIDAY...DDV
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
317 AM CST SAT JAN 21 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
NEAR LAKE MICHIGAN THE MAIN ISSUE WILL BE HANDLING LAKE EFFECT
TRENDS. NORTHEAST WINDS IN SHALLOW LAYER FROM 975 MB TO 900 MB.
LAPSE RATES ARE NOT TO STEEP WITH AROUND 3 C/KM AT MILWAUKEE BUT
NEAR 6C/KM NEAR KENOSHA AT 09Z BUT LAPSE RATES INCREASE TO NEAR
9C/KM AT 18Z WITH INVERSION HEIGHT AROUND 3 THSD FT. LOW LEVEL FLOW
WEAKENS AND BECOMES MORE EAST. THEREFORE EXPECT THE SNOW BAND NEAR
KENOSHA TO CONTINUE TO WEAKEN AND THEN EVENTUALLY BECOME MORE
DIFFUSE WITH GENERAL LIGHT SNOW/FLURRIES NEAR THE LAKE. HRRR SHOWS
THE LAKE BAND PUSHING SOUTH THEN WEAKENING BUT INCREASING IN
COVERAGE. NAM SHOWS SOMETHING SIMILAR.
ELSEWHERE MOISTURE TRAPPED BLOW DEVELOPING INVERSION AROUND
3 THSD FT SHOULD SLOW ANY CLEARING FROM THE WEST. FORECAST
SOUNDINGS SHOW SOME CLEARING POTENTIAL OVER THE FRINGES OF THE
STRATUS SHIELD BUT THEN WITH THE EAST FLOW...LOW LEVELS MOISTEN SO
STRATUS/STRATOCUMULUS COULD EXPAND AGAIN.
MID LEVEL SHORTWAVE OVER THE EASTERN GREAT LAKES EXITS TO THE EAST
WITH MID LEVEL DRYING.
STRONG SHORTWAVE OVER THE PACIFIC NORTHWEST WILL REACH THE ROCKIES
TONIGHT. LOW/MID LEVEL WARM AIR ADVECTION BEGINS BUT THE 850 TO 700
MB LAYER IS FAIRLY DRY SO NOT EXPECTING ANY PRECIPITATION. BY
MIDNIGHT SOUNDINGS SHOW TEMPERATURES AROUND 800 MB ALREADY WARMING
ABOVE 0 CELSIUS OVER MUCH OF THE FORECAST AREA...AND ABOVE 0 C BY
SUNRISE. NAM SHOWS SATURATION BELOW 925 MB BUT DOES NOT APPEAR DEEP
ENOUGH MOIST LAYER FOR FREEZING DRIZZLE.
.SUNDAY AND MONDAY...FORECAST CONFIDENCE...MEDIUM
MODELS SLOWLY COMING INTO BETTER AGREEMENT FOR THE SUNDAY/MONDAY LOW
PRESSURE SYSTEM. THE GFS HAS TRENDED TOWARD THE SLOWER ECMWF AND
CANADIAN SOLUTIONS...WHILE THE NAM REMAINS THE QUICKEST. LEANED
FORECAST PRETTY HEAVILY TOWARD CONSISTENT ECMWF.
OVERALL...LOOKS LIKE A CHANCE FOR WARM ADVECTION PRECIP ON SUNDAY.
MID LEVELS ARE QUITE DRY IN SOUNDINGS...WITH VERY LITTLE ICE
EXPECTED. WITH SFC TEMPS BELOW FREEZING TO START THE DAY...KEPT
MENTION OF FREEZING RAIN. MENTIONED RAIN A CHANCE FOR RAIN AS WELL
IN THE AFTERNOON AS TEMPS WARM ABOVE FREEZING. ONLY REASON SNOW WAS
LEFT IN FOR SUNDAY IS THAT SOME MODELS DO SHOW SOME ICE CRYSTAL
POTENTIAL ABOVE THE DRY LAYER. DRY LAYER LOOKS LIKE IT WILL
GENERALLY DRY UP ANY ICE...BUT POTENTIAL FOR SEEDING IS THERE IF DRY
LAYER IS OVERDONE IN MODELS.
PRECIP AMOUNTS EXPECTED TO BE LIGHT DURING THE DAY SUNDAY...SO ANY
ICING WOULD BE FAIRLY LIMITED.
SFC LOW EXPECTED TO MOVE THROUGH SUNDAY NIGHT...ALONG WITH BEST SHOT
FOR PRECIP FROM THIS STORM. ENOUGH OVERLAP BETWEEN MODELS TO BUMP
POPS UP TO CATEGORICAL. LOOKS LIKE MAINLY RAIN EAST...MIXING WITH
SNOW WEST. MAY SEE EVENTUAL CHANGE OVER TO SNOW WEST TO EAST
BEGINNING LATE SUNDAY NIGHT OR MONDAY MORNING...WITH SOME LIGHT
ACCUMULATIONS POSSIBLE.
WITH DEWPOINTS EXPECTED TO GET INTO THE MID 30S OVER THE
SNOWPACK...AND THE SFC LOW COMING RIGHT OVERHEAD...MENTIONED PATCHY
FOG IN THE EAST SUN NIGHT AND MON MORNING.
.TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
LOOKS FAIRLY QUIET TUESDAY THROUGH THE REMAINDER OF THE WORK WEEK.
MODELS DEPICTING A SERIES OF WEAK SHORTWAVES TO ROLL THROUGH DURING
THIS PERIOD...POSSIBLY BRINGING SOME FLURRIES OR LIGHT SNOW AT
TIMES. NEAR NORMAL TEMPS TUESDAY EXPECTED TO WARM TO A FEW DEGREES
ABOVE NORMAL FOR WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION/12Z TAFS/...
MAINLY MVFR CIGS OVER FAR SOUTH CENTRAL AND PORTIONS OF SOUTHEAST
WISCONSIN. LAKE BAND PUSHING SOUTH BUT STRONGEST RADAR RETURNS HAVE
BEEN STAYING OFF SHORE. AS LOW LEVEL FLOW BECOMES MORE EAST LAKE
EFFECT WILL EXPAND IN COVERAGE BUT SHOULD BE FAIRLY LIGHT...ALTHOUGH
SOME AREAS COULD SEE SOME VERY LIGHT ACCUMULATIONS. CIGS/VSBYS WILL
BE MAINLY MVFR.
THE LOW CLOUD SHIELD MAY ERODE SOMEWHAT FROM THE WEST...BUT THEN
WOULD TEND TO EXPAND AGAIN AS EAST FLOW INCREASES THE LOW LEVEL
MOISTURE.
IFR POTENTIAL LATER TONIGHT AS EAST/SOUTHEAST FLOW INCREASES.
&&
.MARINE...
A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED LATE TONIGHT THROUGH
MONDAY NIGHT AS LOW PRESSURE MOVES EAST AND EXITS THE NORTHERN
PLAINS. BRISK SOUTH WINDS AND HIGH WAVES WILL PREVAIL SATURDAY
NIGHT INTO SUNDAY NIGHT. A COLD FRONT WILL THEN SHIFT THE WINDS TO
THE WEST FOR LATE SUNDAY NIGHT AND INTO MONDAY NIGHT. THE WINDS
WILL CONTINUE TO BE BRISK AND GUSTY AND SMALL CRAFT CONDITIONS
WILL LIKELY PERSIST FOR THIS TIME PERIOD.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SUNDAY THROUGH FRIDAY...DDV
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1042 PM CST FRI JAN 20 2012
.UPDATE...
LAKE EFFECT SNOW BAND HAS NOT SHIFTED SOUTH YET AND IN FACT IS
DRIFTING NORTH. ADDED MILWAUKEE COUNTY BUT EXPECT BAND TO STAY
SOUTH OF THE CITY OF MILWAUKEE. LOOKS LIKE SNOWFALL RATES PER KMKX
DOPPLER RADAR ARE ON THE ORDER OF 0.50" PER HOUR.
LATEST HRRR HAS BAND STARTING TO SHIFT SOUTH IN ABOUT 5 HOURS SO
COULD END UP WITH 3-4 INCHES NEAR SOUTH MILWAUKEE AND OAK CREEK
BEFORE IT DOES SO.
NATURALLY WITH LAKE EFFECT UNCERTAINTY IS ALWAYS PRETTY HIGH AND
THE LATEST GUIDANCE ALL HAS A GENERAL HANDLE ON THE LOCATION AND
TIMING BUT EACH IS ABOUT A COUNTY OFF. MOST OF THE CURRENT
GUIDANCE SUGGESTS THAT THE BAND SHOULD BE OFFSHORE. 00Z NAM HOLDS
THE BAND IN MILWAUKEE COUNTY FOR A WHILE BEFORE SHIFTING SOUTH.
SINCE HRRR AND LOCAL 4KM RUN ARE SIMILAR...WILL GO WITH THAT
SCENARIO FOR NOW.
AT THIS POINT KENOSHA COUNTY ADVISORY MAY BE OVERDONE BUT THE BAND
SEEMS LIKELY TO SHIFT SOUTH EVENTUALLY AND KMKE TDWR HAS SHOWN
FLOW AT 925 MB GRADUALLY BACK TO MORE NORTHERLY WITH TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM CST SATURDAY FOR WIZ066-071-
072.
LM...NONE.
&&
$$
UPDATE...CRAVEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
454 AM EST MON JAN 23 2012
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE AND PROVIDE THE
REGION WITH SOME LIGHT ICING CONDITIONS THIS MORNING. TEMPERATURES
WILL CLIMB ABOVE FREEZING THIS AFTERNOON FOR MAINLY RAIN SHOWERS
THAT WILL ACCOMPANY THE FRONTAL BOUNDARY. SOMEWHAT COOLER AIR WILL
FILTER IN FOR TUESDAY WITH SOME LAKE EFFECT SNOW DOWNWIND OF LAKE
ONTARIO. TRANQUIL CONDITIONS FOR THE MID WEEK AS A RIDGE OF HIGH
PRESSURE TRACKS ACROSS THE AREA.
&&
.NEAR TERM /UNTIL NOON TODAY/...
VERY CHALLENGING NEAR TERM FORECAST AS FZDZ HAS NOT MATERIALIZED
AT THIS TIME. PER METARS...THE CIGS REMAIN RATHER HIGH AND
DEWPOINT DEPRESSIONS ARE 5 DEGREES OR GREATER. WE DID RECEIVE A
REPORT OF FLURRIES IN LITCHFIELD COUNTY AND THIS CAN ALSO BE
CONFIRMED WITH SEVERAL METARS ACROSS THE NYC METRO AREA REPORTING
LIGHT SNOW. THIS MAY BE DUE TO THE OCEANIC EFFECT ADDING ENOUGH
NUCLEI TO RESULT IN THOSE OBS OF LIGHT SNOW. THE FORECAST
SOUNDINGS ACROSS OUR REGION STILL SUGGEST THE BOUNDARY LAYER WILL
MOISTEN UP BELOW THE -10C ISOTHERM INCLUDING THE SHEAR PROFILES
FOR SOME DRIZZLE FORMATION. RUC13 FORECAST SOUNDINGS DELAY THE
ONSET OF MOISTURE UNTIL THE 12-15Z TIME FRAME. BY THAT
TIME...TEMPERATURES ARE BEGINNING TO CLIMB TO AT OR ABOVE
FREEZING ALONG AND SOUTH OF I90. THE COLDER AIR IS EXPECTED TO
REMAIN IN PLACE LONGER ACROSS THE DACKS...LAKE GEORGE SARATOGA
REGION AND SOUTHERN VERMONT UNTIL ABOUT THE NOON HOUR. THE
ADVISORY LOOKS GOOD AT THIS TIME WITH NO CHANGES EXPECTED.
&&
.SHORT TERM /NOON TODAY THROUGH WEDNESDAY/...
POTENT SHORT WAVE TRACKING NORTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY INTO THE GREAT LAKES REGION WILL SEND A COLD FRONT EASTWARD
THIS AFTERNOON. A BAND OF BKN SHOWERS IS EXPECTED AND WE WILL
PLACE CATEGORICAL POPS FOR THE ENTIRE REGION. TIMING OF THIS FRONT
APPEARS TO BE AOA 21Z. AS FOR CONVECTIVE POTENTIAL /IE
THUNDER/...THE SHOWALTER INDEX IS EXPECTED TO DROP TOWARD 0C FOR
PORTIONS OF THE REGION WITH THE BEST UPPER SUPPORT FOR THE WESTERN
MOHAWK VALLEY AND DACKS. WHILE WE WILL NOT INCLUDE THUNDER...WOULD
NOT TOTALLY RULE OUT A RUMBLE OF THUNDER.
WITH FROPA...DRY SLOT QUICKLY APPROACHES THIS EARLY EVENING. SOME
LINGERING UPSLOPE SHOWERS ARE EXPECTED BUT THIS TOO SHOULD
DECREASE THROUGH TONIGHT. SEEMS THE INITIAL COLD ADVECTION WILL
REMAIN WEST OF THE HUDSON RIVER VALLEY WITH TEMPERATURES OVERNIGHT
REMAINING ABOVE FREEZING FOR A GOOD PORTION OF THE REGION. THE
EXCEPTION TO THIS WILL BE FOR PORTIONS OF THE DACKS. LAKE ONTARIO
CONTRIBUTION INCREASES A BIT...ALBEIT MARGINALLY...TO WARRANT
CHANCE POPS FOR RAIN/SNOW SHOWERS TRANSITIONING TO SNOW SHOWER
OVERNIGHT.
DUE TO A RELATIVELY MILDER START TO THE DAY TUESDAY...TEMPERATURES
FOR THE REGION SHOULD ONCE AGAIN CLIMB ABOVE THE FREEZING WITH MID
40S EXPECTED FOR THE MID HUDSON RIVER VALLEY AND NW CT. CYCLONIC
FLOW REMAINS OVER LAKE ONTARIO AND THE DACKS WITH A VEERING WIND
PROFILE TO TAKE WHAT BANDS OF LAKE EFFECT ACTIVITY FURTHER SOUTH.
SECONDARY COLD FRONT IS EXPECTED TO CLEAR THE REGION LATE TUESDAY
AFTERNOON WITH 850MB TEMPS EXPECTED TO PLUNGE BACK BELOW -10C FOR
THE ENTIRE CWA. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A BRIEF
ORGANIZED LAKE EFFECT WITH CLIMBING INVERSION HEIGHTS TUESDAY
EVENING BEFORE FALLING ONCE AGAIN OVERNIGHT. AT THIS POINT...SEEMS
ACCUMULATIONS WILL BE LIMITED AND ISOLATED WITH GENERALLY AROUND 1
INCH. AS UPPER TROUGH SLIDES EAST OF THE REGION...INVERSION
HEIGHTS DROP QUICKLY AS DOES THE DRY AIR ADVECTION ACROSS NY
STATE.
A NARROW SURFACE RIDGE IS EXPECTED ACROSS THE REGION DESPITE
ANOTHER SHORT WAVE MOVING ACROSS THE NORTHERN TIER OF NY AND NEW
ENGLAND. WITH LIMITED MOISTURE...WE WILL KEEP SKIES PTCLOUDY AND
NO MENTION OF PRECIP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE PERIOD WILL START OUT WITH A RIDGE MOVING ACROSS THE REGION AT
THE SURFACE WITH THE FLOW ALOFT FLATTENING. THE MODELS ARE IN FAIRLY
GOOD AGREEMENT WITH THE LONGWAVE PATTERN...HOWEVER THERE ARE
DIFFERENCES IN THE TIMING AND TRACK OF THE SOUTHERN STREAM SYSTEM
WHICH ORIGINATES OVER THE SOUTHERN PLAINS AND HEADS OUR WAY LATE IN
THE WEEK. THERE IS A QUESTION OF HOW MUCH INTERACTION THERE WILL BE
WITH THE NORTHERN STREAM. AT THIS TIME...THIS SYSTEM IS EXPECTED TO
PASS TO SOUTH BRINGING THE CHANCES FOR PRECIPITATION TO THE AREA
THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO RUN ABOVE
NORMAL WITH THE LONGWAVE PATTERN KEEPING THE COLDER AIR TO OUR NORTH
THROUGH THE WORK WEEK. INDICATIONS ARE NORTHERN STREAM ENERGY WILL
DIVE INTO THE NORTHERN PLAINS CAUSING A TROUGH TO DIG OVER THE
EASTERN UNITED STATES OVER THE WEEKEND RETURNING MORE SEASONABLE AIR
TO THE REGION.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL LOWER TO MVFR EARLY THIS MORNING AS THE LOW
LEVELS OF THE ATMOSPHERE MOISTEN UP AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. THE CHANCES FOR FREEZING DRIZZLE WILL THEN
INCREASE. TEMPERATURES ARE EXPECTED TO RISE TO ABOVE THE FREEZING
MARK BEFORE THE STEADIER AND HEAVIER PRECIPITATION MOVES IN THIS
AFTERNOON WITH CONDITIONS LOWERING TO IFR. THE STEADY PRECIPITATION
WILL MOVE OFF TO THE EAST DURING THE EVENING HOWEVER IFR CONDITIONS
ARE EXPECTED TO LINGER.
OUTLOOK...
MON NIGHT...MVFR/IFR...IMPROVING TO MVFR/VFR. RAIN TAPERING OFF TO
SCATTERED SHOWERS.
TUE-WED...VFR. NO SIG WX.
THU...MAINLY VFR. CHC -RA/-SN BY LATE IN THE AFTERNOON.
THU NIGHT-FRI..VFR/MVFR. CHC -SHSN/-SHRA.
&&
.HYDROLOGY...
A STORM SYSTEM WILL BRING MIXED PRECIPITATION CHANGING TO RAIN
TODAY. A QUICK SHOT OF MODERATE TO HEAVY RAIN IS POSSIBLE THIS
AFTERNOON WITH A COLD FRONT AS QPF VALUES ARE EXPECTED TO BE BETWEEN
ONE QUARTER TO ONE HALF INCH WITH LOCALIZED AMOUNTS AROUND AN INCH
POSSIBLE INTO THE HIGHER TERRAIN OF THE CATSKILLS...SOUTHERN VERMONT
AND BERKSHIRES.
WE MEASURED THE GROUND FROZEN TO A DEPTH OF 14 INCHES HERE AT THE
OFFICE ON SUNDAY. SOME LOCALIZED POOR DRAINAGE...URBAN AND SMALL
STREAM FLOODING MAY BE POSSIBLE LATER MONDAY DUE TO ENHANCED RUNOFF
FROM RAIN AND MELT ON FROZEN GROUND.
SOME SIGNIFICANT RISES ON MAIN STEM RIVERS ARE POSSIBLE MONDAY INTO
TUESDAY...BUT LARGER RIVER FLOODING IS NOT EXPECTED AT THIS TIME.
RISES WOULD BE ENOUGH TO BREAK UP WHAT RIVER ICE IS IN PLACE BUT ICE
IS NOT THICK ENOUGH TO CAUSE SIGNIFICANT ICE JAM PROBLEMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR CTZ001-013.
NY...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NYZ039-040-
047>054-058>061-063>066.
FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NYZ032-033-038-041>043-082>084.
MA...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
VT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...SND/BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS ALBANY NY
426 AM EST MON JAN 23 2012
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE AND PROVIDE THE
REGION WITH SOME LIGHT ICING CONDITIONS THIS MORNING. TEMPERATURES
WILL CLIMB ABOVE FREEZING THIS AFTERNOON FOR MAINLY RAIN SHOWERS
THAT WILL ACCOMPANY THE FRONTAL BOUNDARY. SOMEWHAT COOLER AIR WILL
FILTER IN FOR TUESDAY WITH SOME LAKE EFFECT SNOW DOWNWIND OF LAKE
ONTARIO. TRANQUIL CONDITIONS FOR THE MID WEEK AS A RIDGE OF HIGH
PRESSURE TRACKS ACROSS THE AREA.
&&
.NEAR TERM /UNTIL NOON TODAY/...
VERY CHALLENGING NEAR TERM FORECAST AS FZDZ HAS NOT MATERIALIZED
AT THIS TIME. PER METARS...THE CIGS REMAIN RATHER HIGH AND
DEWPOINT DEPRESSIONS ARE 5 DEGREES OR GREATER. WE DID RECEIVE A
REPORT OF FLURRIES IN LITCHFIELD COUNTY AND THIS CAN ALSO BE
CONFIRMED WITH SEVERAL METARS ACROSS THE NYC METRO AREA REPORTING
LIGHT SNOW. THIS MAY BE DUE TO THE OCEANIC EFFECT ADDING ENOUGH
NUCLEI TO RESULT IN THOSE OBS OF LIGHT SNOW. THE FORECAST
SOUNDINGS ACROSS OUR REGION STILL SUGGEST THE BOUNDARY LAYER WILL
MOISTEN UP BELOW THE -10C ISOTHERM INCLUDING THE SHEAR PROFILES
FOR SOME DRIZZLE FORMATION. RUC13 FORECAST SOUNDINGS DELAY THE
ONSET OF MOISTURE UNTIL THE 12-15Z TIME FRAME. BY THAT
TIME...TEMPERATURES ARE BEGINNING TO CLIMB TO AT OR ABOVE
FREEZING ALONG AND SOUTH OF I90. THE COLDER AIR IS EXPECTED TO
REMAIN IN PLACE LONGER ACROSS THE DACKS...LAKE GEORGE SARATOGA
REGION AND SOUTHERN VERMONT UNTIL ABOUT THE NOON HOUR. THE
ADVISORY LOOKS GOOD AT THIS TIME WITH NO CHANGES EXPECTED.
&&
.SHORT TERM /NOON TODAY THROUGH WEDNESDAY/...
POTENT SHORT WAVE TRACKING NORTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY INTO THE GREAT LAKES REGION WILL SEND A COLD FRONT EASTWARD
THIS AFTERNOON. A BAND OF BKN SHOWERS IS EXPECTED AND WE WILL
PLACE CATEGORICAL POPS FOR THE ENTIRE REGION. TIMING OF THIS FRONT
APPEARS TO BE AOA 21Z. AS FOR CONVECTIVE POTENTIAL /IE
THUNDER/...THE SHOWALTER INDEX IS EXPECTED TO DROP TOWARD 0C FOR
PORTIONS OF THE REGION WITH THE BEST UPPER SUPPORT FOR THE WESTERN
MOHAWK VALLEY AND DACKS. WHILE WE WILL NOT INCLUDE THUNDER...WOULD
NOT TOTALLY RULE OUT A RUMBLE OF THUNDER.
WITH FROPA...DRY SLOT QUICKLY APPROACHES THIS EARLY EVENING. SOME
LINGERING UPSLOPE SHOWERS ARE EXPECTED BUT THIS TOO SHOULD
DECREASE THROUGH TONIGHT. SEEMS THE INITIAL COLD ADVECTION WILL
REMAIN WEST OF THE HUDSON RIVER VALLEY WITH TEMPERATURES OVERNIGHT
REMAINING ABOVE FREEZING FOR A GOOD PORTION OF THE REGION. THE
EXCEPTION TO THIS WILL BE FOR PORTIONS OF THE DACKS. LAKE ONTARIO
CONTRIBUTION INCREASES A BIT...ALBEIT MARGINALLY...TO WARRANT
CHANCE POPS FOR RAIN/SNOW SHOWERS TRANSITIONING TO SNOW SHOWER
OVERNIGHT.
DUE TO A RELATIVELY MILDER START TO THE DAY TUESDAY...TEMPERATURES
FOR THE REGION SHOULD ONCE AGAIN CLIMB ABOVE THE FREEZING WITH MID
40S EXPECTED FOR THE MID HUDSON RIVER VALLEY AND NW CT. CYCLONIC
FLOW REMAINS OVER LAKE ONTARIO AND THE DACKS WITH A VEERING WIND
PROFILE TO TAKE WHAT BANDS OF LAKE EFFECT ACTIVITY FURTHER SOUTH.
SECONDARY COLD FRONT IS EXPECTED TO CLEAR THE REGION LATE TUESDAY
AFTERNOON WITH 850MB TEMPS EXPECTED TO PLUNGE BACK BELOW -10C FOR
THE ENTIRE CWA. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A BRIEF
ORGANIZED LAKE EFFECT WITH CLIMBING INVERSION HEIGHTS TUESDAY
EVENING BEFORE FALLING ONCE AGAIN OVERNIGHT. AT THIS POINT...SEEMS
ACCUMULATIONS WILL BE LIMITED AND ISOLATED WITH GENERALLY AROUND 1
INCH. AS UPPER TROUGH SLIDES EAST OF THE REGION...INVERSION
HEIGHTS DROP QUICKLY AS DOES THE DRY AIR ADVECTION ACROSS NY
STATE.
A NARROW SURFACE RIDGE IS EXPECTED ACROSS THE REGION DESPITE
ANOTHER SHORT WAVE MOVING ACROSS THE NORTHERN TIER OF NY AND NEW
ENGLAND. WITH LIMITED MOISTURE...WE WILL KEEP SKIES PTCLOUDY AND
NO MENTION OF PRECIP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
FORTHCOMING...
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL LOWER TO MVFR EARLY THIS MORNING AS THE LOW
LEVELS OF THE ATMOSPHERE MOISTEN UP AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. THE CHANCES FOR FREEZING DRIZZLE WILL THEN
INCREASE. TEMPERATURES ARE EXPECTED TO RISE TO ABOVE THE FREEZING
MARK BEFORE THE STEADIER AND HEAVIER PRECIPITATION MOVES IN THIS
AFTERNOON WITH CONDITIONS LOWERING TO IFR. THE STEADY PRECIPITATION
WILL MOVE OFF TO THE EAST DURING THE EVENING HOWEVER IFR CONDITIONS
ARE EXPECTED TO LINGER.
OUTLOOK...
MON NIGHT...MVFR/IFR...RA LIKELY EARLY...THEN VFR/MVFR WITH SCT
-SHRA/-SHSN LATE.
TUE-WED...VFR...NO SIG WX.
THU-FRI. VFR. SLIGHT CHC -SHSN/-SHRA.
&&
.HYDROLOGY...
A STORM SYSTEM WILL BRING MIXED PRECIPITATION CHANGING TO RAIN
TODAY. A QUICK SHOT OF MODERATE TO HEAVY RAIN IS POSSIBLE THIS AFTERNOON
WITH A COLD FRONT AS QPF VALUES ARE EXPECTED TO BE BETWEEN ONE
QUARTER TO ONE HALF INCH WITH LOCALIZED AMOUNTS AROUND AN INCH
POSSIBLE INTO THE HIGHER TERRAIN OF THE CATSKILLS...SOUTHERN
VERMONT AND BERKSHIRES.
WE MEASURED THE GROUND FROZEN TO A DEPTH OF 14 INCHES HERE AT THE
OFFICE ON SUNDAY. SOME LOCALIZED POOR DRAINAGE...URBAN AND SMALL
STREAM FLOODING MAY BE POSSIBLE LATER MONDAY DUE TO ENHANCED RUNOFF
FROM RAIN AND MELT ON FROZEN GROUND.
SOME SIGNIFICANT RISES ON MAIN STEM RIVERS ARE POSSIBLE MONDAY INTO
TUESDAY...BUT LARGER RIVER FLOODING IS NOT EXPECTED AT THIS TIME.
RISES WOULD BE ENOUGH TO BREAK UP WHAT RIVER ICE IS IN PLACE BUT ICE
IS NOT THICK ENOUGH TO CAUSE SIGNIFICANT ICE JAM PROBLEMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR CTZ001-013.
NY...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NYZ039-040-
047>054-058>061-063>066.
FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NYZ032-033-038-041>043-082>084.
MA...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
VT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...SND/BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
245 AM CST MON JAN 23 2012
.DISCUSSION...
910 PM CST
NOT MUCH CHANGE TO THE GOING FORECAST THIS EVENING. TRENDS ARE
PANNING OUT AS EXPECTED AND ARE IN A MONITOR MODE WITH THE
CONVECTION TO THE SOUTH. ACROSS THE AREA...VAD WIND PROFILE SHOW
WINDS AT 1KFT GENERALLY OUT OF THE SOUTHEAST AT 20 OR SO KT...AND
AT 3KFT...SOUTH TO SOUTHWEST AT 50 TO 55KT. MODEL PROGS SHOW THAT
THE LLJ WILL CONTINUE TO INCREASE AND WILL GIVE ANY STORMS THAT
WORK THROUGH...THE POTENTIAL BE STRONG. MID LEVEL LAPSE RATES HAD
BEEN PROGGED TO RANGE FROM 6-7.5 C/KM THIS EVE...BUT RUC ANALYSIS
SHOWED THAT BEING ON THE WANE AS OF 03Z...WITH THE HIGHEST VALUES
SHIFTING EAST. DESPITE THE SURGE OF WARMTH AND
MOISTURE...CONVECTION WILL HAVE TO STRUGGLE AGAINST A STABLE
SURFACE AIRMASS. THE BEST FOCUS STILL SET TO REMAIN SOUTH FOR
SEVERE ACTIVITY...WITH THE BEST FOCUS LOCALLY...GENERALLY EAST OF
THE I-57 CORRIDOR THROUGH THE MIDNIGHT HOUR WHERE A FEW RUMBLES OF
THUNDER MAY BE HEARD. LATEST GRIDS AND ZONES ARE OUT. SHEA
//PREV DISCUSSION...
357 PM CST
JUST 48 HOURS AFTER A WINTER STORM...THE WEATHER WILL SWING
VIGOROUSLY THE OTHER WAY ACROSS THE MIDDLE OF THE COUNTRY
TONIGHT. MUCH OF THE ATTENTION ON THE FORECAST WAS SPENT ON THE
PRESENT THROUGH MONDAY...WITH CONCERNS ON DENSE FOG...INITIAL
FREEZING DRIZZLE...CONVECTION...GUSTY WINDS...AND SOME SNOW TO
ROUND IT OUT DURING MONDAY.
SYNOPSIS...THE WELL-DEFINED UPPER LOW IS TAKING BETTER SHAPE OVER
THE CENTRAL PLAINS THIS AFTERNOON...WITH SIGNS OF A STRONG MID-
LEVEL JET AND DRY SLOT DEVELOPING INTO THE OZARKS. THE SURFACE LOW
AT 992 MB OVER EASTERN KS HAS BEEN SLIGHTLY DEEPER THAN SOME OF
THE MODELS HAD INDICATED FOR THIS AFTERNOON. THE PRIMARY SURFACE
THETA-E GRADIENT IS DRAPED FROM NORTHERN MO INTO SOUTHERN IL.
LOW-LEVEL FLOW HAS BEEN INCREASING OVER THE FORECAST AREA...WHICH
IN PLACES HAS CAUSED SOME BLOWING AND DRIFTING OF THE LIGHT AND
FLUFFY SNOW SEEN THIS PAST FRIDAY. TEMPERATURES HAVE RESPONDED TO
THE RETURN FLOW AS WELL...CLIMBING INTO THE MID 30S ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA. INCREASING SURFACE
TEMPERATURES AND DEW POINTS WILL CONTINUE INTO TONIGHT...WITH THE
PRIMARY GRADIENT MARCHING MORE QUICKLY NORTH THROUGH IL AND IN
THAN IT HAD TODAY AS CYCLOGENESIS FURTHER OCCURS. THE SURFACE LOW
WILL SHIFT NORTHEAST TO NEAR THE QUAD CITIES BY 3 AM AS THE UPPER
TROUGH BECOMES NEGATIVELY TILED. THE COLD FRONT WILL PUSH QUICKLY
FROM SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA BETWEEN 3 AM
AND 7 AM...WITH LIKELY AN AREA OF SHOWERS AND CONVECTION AHEAD OF
IT BETWEEN 10 PM AND 3 AM. THE LOW WILL THEN SHIFT ON TO THE
NORTHERN PART OF LAKE MICHIGAN BY LATE MONDAY...KEEPING WESTERLY
WINDS GUSTY HERE.
DRIZZLE/FOG/BLOWING SNOW TONIGHT...THE EXPANSION OF DRIZZLE
ACROSS THE AREA EARLY THIS AFTERNOON LINED UP WELL WITH SATURATION
AND SOME WEAK ADIABATIC OMEGA ON THE 275K AND 280K SURFACES.
CONTINUING TO LOOK AT NEAR-SURFACE LAYERS INTO TONIGHT ON THE
RUC...THE PROJECTION IS FOR THE GREATER LIFT IN SATURATION TO MOVE
NORTH OF THE AREA BY EARLY TO MID EVENING. IN ADDITION...THE
SURFACE TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING IN ALL
AREAS BY 6 PM. IN THE DIRECT PATH OF THE LOW...TOWARDS
NORTHWEST/NORTH CENTRAL IL...THE WINDS WILL ACTUALLY BEGIN TO
DECREASE WITHIN THE INFLECTION IN THE PRESSURE PATTERN. THIS MAY
ALLOW CURRENT VISIBILITY TO FURTHER REDUCE FOR SOME DENSE FOG. AT
THIS POINT HAVE JUST HIGHLIGHTED WITH AREAS OF FOG TONIGHT. EXPECT
THAT WITH THE WINDS FORECAST TONIGHT SOME OF THIS SHALLOW
BLOWING/DRIFTING WILL CONTINUE IN RURAL AREAS. WILL MENTION IN THE
FORECAST AND MONITOR CLOSELY.
THUNDERSTORM CHANCES TONIGHT...AFTER A PRECIPITABLE WATER OF ONLY
0.20 ON THE MORNING ILX SOUNDING...A SIGNIFICANT REBOUND TO NEAR
1.1 INCHES IS EXPECTED TONIGHT ACROSS CENTRAL AND EASTERN IL INTO
IN. THIS IS PART OF AN ANOMALOUSLY STRONG LOW LEVEL JET...WHICH THE
22.12 NAM HAD AT SEVEN STANDARDIZED ANOMALIES ABOVE NORMAL. THIS
STRONG WIND FIELD IS WHAT WOULD GIVE ANY THUNDERSTORMS THE CHANCE
TO BE SEVERE...COMPENSATING FOR LIMITED LOW-LEVEL
INSTABILITY/FAVORABLE LAPSE RATES. MARGINAL INSTABILITY ALOFT IS
PRESENT...AT 500-1000 J/KG IN THE FAR SOUTHEAST/...HELPED BY
STRONG DIFFERENTIAL THETA-E ADVECTION WITH THE DRY SLOT INTRUSION.
THIS OVERRIDES THE SURFACE FOCUS OF A COLD FRONT /AND POSSIBLY A
PRE-FRONTAL TROUGH JUST AHEAD OF THIS/...WHICH SHOULD HELP
CONVECTION TO DEVELOP AND EVOLVE DURING THE 7 PM TO 10 PM TIME
ACROSS SOUTHWEST INTO CENTRAL IL.
BOUNDARY LAYER DEW POINTS IN EXCESS OF 50F ARE PROJECTED BY THE
NAM/GFS TO BE NEAR THE SOUTHEAST FORECAST AREA EDGE...WHICH WILL
KEEP THE LOWER PROFILES MOIST BASED ON FORECAST SOUNDINGS. GIVEN
THE VERY CLOSE PROXIMITY OF THE SNOW COVER EDGE BASED ON THIS
MORNINGS OBSERVATIONS...EVEN HIGHER TEMPERATURE AND DEW POINTS
/BUT WITH THE SAME LOW TEMP AND DEW POINT SPREADS/ MAY BE SEEN
INTO THE SOUTHEAST FORECAST AREA. THIS SETUP WOULD FURTHER HELP
FOR WINDS TO PUNCH THE INVERSION AND MAKE IT TO THE SURFACE WITHIN
SHOWERS AND ESPECIALLY ORGANIZED THUNDERSTORMS. FORECAST NAM
SOUNDINGS AT CHAMPAIGN SHOW ALMOST 70 KTS AND 3000 FT...SO PLENTY
AVAILABLE TO MIX DOWN. THIS SETUP WILL NEED TO BE WATCHED TOO FOR
THE CHANCE OF A TORNADO AS FAR NORTH AS OUR SOUTHEAST FORECAST
AREA...AS FORECAST PROFILES AND SYNOPTICS APPROACH THOSE THAT CAN
PRODUCE COOL SEASON EPISODES.
TO THE NORTH OF THE SEVERE CONVECTIVE THREAT...RAIN SHOWERS ARE
EXPECTED WITH POTENTIAL THUNDER. SOME OF THE RAINFALL RATES COULD
BE TEMPORARILY HEAVY...WHICH COULD FURTHER AGGRAVATE RUNOFF
ALREADY HEIGHTENED FROM SNOW MELT TONIGHT.
MONDAY...THE COLD AIR ADVECTION WILL WRAP IN QUICKLY BEHIND THE
FRONT. PARAMETERS FOR GUSTY WINDS...SUCH AS STEEPENED LOW-LEVEL
LAPSE RATES AND STRONG LOW-LEVEL Q-VECTOR DIVERGENCE...ARE BEST
SEEN IN THE SOUTHERN FORECAST AREA. WIND GUSTS TO NEAR 40 MPH ARE
EXPECTED AND IT IS POSSIBLE A WIND ADVISORY WILL BE NEEDED IN
TIME. THE SOUTHERN PART OF THE OVERALL UPPER TROUGH WILL MOVE
ACROSS THE AREA...LIKELY PRODUCING SOME SNOW FOR NORTHERN AREAS.
SOME MINOR ACCUMULATION UP TO POSSIBLY AN INCH COULD OCCUR NEAR
THE STATE LINE. BY MID TO LATE AFTERNOON...DEEP NVA IS FORECAST
WHICH SHOULD END ANY LIGHT SNOW/FLURRIES. CLOUDS WILL BE SLOWER TO
CLEAR...WITH SOME STILL HOLDING ON IN NORTHERN AND EASTERN AREAS
ON TUESDAY MORNING.
BEYOND...LITTLE CHANGES MADE TO THIS PORTION OF THE
FORECAST...WHICH LOOKS RELATIVE QUIET COMPARED TO THE PAST TEN
DAYS. A BLEND OF THE BETTER PERFORMING MODELS AND THE GOING FORECAST
WAS PRUDENT AT THIS TIME.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* VARIABLE CIGS/VSBY WITH PERIOD OF MVFR/VFR OCCURRING NOW BUT
IFR/LIFR EXPECTED TO RETURN...BUT TIMING IS NOT CLEAR.
* ANOTHER ROUND OF TS POSSIBLE STARTING AROUND 10Z.
* WINDS BECOMING LIGHT SSE WITH APPROACH OF SFC LOW LATE TONIGHT.
* WINDS BECOMING WEST AND GUSTING TO/ABOVE 30 KTS AT TIMES MONDAY
AFTERNOON.
* GRADUAL IMPROVEMENT IN CIG/VIS TRENDS MONDAY...THOUGH SNOW
SHOWERS POSSIBLE THROUGH MID AFTERNOON.
MDB
//DISCUSSION...UPDATED 08Z...
BULK OF THE SHRA/TSRA NOW OFF TO THE EAST OF THE TERMINALS BUT HAS
CAUSED HAVOC WITH CIGS/VSBY IN ITS WAKE. CORRIDOR OF MVFR AND EVEN
VFR CIGS/VSBY NOW EXTENDS EAST OF A LINE FROM APPROX SPI-PNT-ORD
WITH LIFR/VLIFR TO THE WEST. EXPECT THAT IFR/LIFR CONDITIONS WILL
RETURN TO ORD/MDW/GYY AT SOME POINT IN THE NEXT FEW HOURS GIVEN
THE APPROACH OF THE LOW AND WEAKENING LOW SURFACE FLOW ALLOWING
FOG/CIGS TO REDEVELOP/EXPAND BACK EAST. HOWEVER IT IS NOT CLEAR
HOW LONG THIS WILL TAKE. ANOTHER ROUND OF SHRA/TSRA IS CURRENTLY
APPROACHING RFD AND THE EXTREME WESTERN CHI METRO AT 0840Z AND
WILL QUICKLY LIFT NORTHEASTWARD. COVERAGE IS MUCH MORE SCATTERED
THAN EARLIER ROUND BUT BRIEF TS MAY OCCUR.
FROM 06Z...
RATHER COMPLICATED AVIATION WEATHER SCENARIO THROUGH MONDAY
MORNING AS STRONG LOW PRESSURE SYSTEM MOVES ACROSS THE FORECAST
AREA. LOW CIGS...REDUCED VSBY IN FOG...RA/TSRA ALL FACTORS FOR
TERMINALS THROUGH DAYBREAK.
DEEP LOW PRESSURE WAS LOCATED OVER FAR NORTHEAST MISSOURI AT
05Z...IN ASSOCIATION WITH A STRONG UPPER LEVEL DISTURBANCE LIFTING
THROUGH THE MID-MISSISSIPPI VALLEY. UNSEASONABLY WARM/MOIST AIR
CONTINUED TO SURGE NORTH INTO THE FORECAST AREA ALONG AND SOUTH OF A
WARM FRONT WHICH EXTENDED ACROSS CENTRAL/NORTHERN IL AND IND. THIS
WARM/MOIST AIR LIFTING ACROSS COLD GROUND AND SNOW COVER ACROSS
THE REGION HAS LED TO DEVELOPMENT OF EXTENSIVE IFR/LIFR STRATUS
AND FOG...AND HAS RESULTED IN SUFFICIENT ELEVATED INSTABILITY TO
PRODUCE THUNDERSTORMS AS FAR NORTH AS NORTHEAST ILLINOIS AND
SOUTHERN LAKE MICHIGAN.
SURFACE LOW IS EXPECTED TO LIFT NORTHEAST ACROSS NORTHERN ILLINOIS
THROUGH THE REMAINDER OF THE OVERNIGHT HOURS...PASSING JUST NORTH
OF CHICAGO AROUND SUNRISE. THIS WILL KEEP MUCH OF FORECAST AREA IN
VERY MOIST LOW LEVEL ENVIRONMENT THROUGH MORNING...SUPPORTING
CONTINUED LOW CIGS AND FOG. WELL-ORGANIZED AREA OF RAIN AND
EMBEDDED THUNDERSTORMS OVER EASTERN IL AND IL/IN STATE LINE REGION
AT THIS TIME SHOULD CONTINUE TO MOVE EAST/NORTHEAST OVER THE NEXT
FEW HOURS...AND MAY ACTUALLY IMPROVE VISIBILITY FOR A TIME AT TAF
SITES. AM CONCERNED HOWEVER THAT AS RAIN WEAKENS DURING THE PRE-
DAWN HOURS THAT CIGS/VIS MAY AGAIN LOWER INTO SOLID LIFR...
ESPECIALLY WITH WINDS DECREASING IN THE WEAKER PRESSURE GRADIENT
NEAR THE CENTER OF THE APPROACHING SFC LOW. ALSO...A SMALL BUT
PERSISTENT AREA OF SHRA/TSRA OVER NORTHEAST MO WITH THE UPPER LOW
CENTER WILL LIKELY LIFT NORTHEAST ACROSS FAR NORTHERN IL WITH THE
LOW THROUGH 12Z OR SO. THIS MAY BRING ANOTHER ROUND OF MORE
ISOLATED TS TO NORTHERN IL TERMINALS TOWARD MORNING.
ONCE SFC LOW PASSES EARLY MONDAY MORNING...WINDS WILL SHIFT TO THE
WEST AND BEGIN TO INCREASE...AS THE GRADIENT TIGHTENS BEHIND THE
DEPARTING LOW AND COLD ADVECTION STRENGTHENS. THIS WILL ALLOW FOR
GRADUAL IMPROVEMENT IN VIS AND CIGS TO MVFR RANGE DURING THE DAY.
ANY LINGERING LIGHT RAIN/SHOWERS WILL LIKELY CHANGE TO LIGHT SNOW
BY LATE MORNING/MIDDAY...AND MAY LAST THROUGH MID AFTERNOON OR SO
BEFORE DIMINISHING TO FLURRIES AND ENDING. STEEPENING LOW LEVEL
LAPSE RATES IN COLDER AIR COMBINED WITH STRONG PRESSURE GRADIENT
IS EXPECTED TO RESULT IN WINDY CONDITIONS MONDAY...WITH GUSTS
INCREASING TO AROUND OR JUST ABOVE 30 KTS BY MONDAY AFTERNOON.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* MEDIUM CONFIDENCE THAT IFR/LIFR WILL RETURN AT SOME POINT IN THE
NEXT FEW HOURS BUT LOW CONFIDENCE IN TIMING.
* MEDIUM CONFIDENCE IN ADDITIONAL TSRA STARTING AROUND 10Z.
* MEDIUM CONFIDENCE IN WIND DETAILS EARLY MONDAY NEAR SFC LOW CENTER.
* MEDIUM-HIGH CONFIDENCE IN IMPROVING CIG/VIS MONDAY AND GUSTY
WEST WINDS AND LIGHT SNOW SHOWERS.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...SLIGHT CHANCE OF SNOW SHOWERS LATE...MAINLY VFR.
SATURDAY...VFR.
RATZER
&&
.MARINE...
240 PM CST
DEEP AREA OF LOW PRESSURE WILL LIFT NORTH ACROSS LAKE MICHIGAN
OVERNIGHT WITH STRONG SOUTHERLY WINDS AHEAD OF THE LOW BECOMING
SOUTHWEST AS THE LOW SWEEPS ACROSS THE LAKE. LOW END GALES ARE
POSSIBLE ACROSS CENTRAL PORTIONS OF THE LAKE THROUGH THIS
EVENING...AND WILL ADVECT MOIST DEWPOINTS OVER THE LAKE SETTING UP
THE POTENTIAL FOR DENSE FOG...AS WELL AS THUNDERSTORMS ACROSS THE
SOUTHERN PORTIONS OF THE LAKE. EXPECT A BRIEF LULL IN THE GALES AS
THE PRESSURE GRADIENT BECOMES MORE BAGGY NEAR THE LOW CENTER...
BEFORE STRONGER GALES RESUME MONDAY MORNING. COLD AIR SWEEPING
ACROSS THE LAKE WILL ALLOW FOR DEEP MIXING AND 40 TO 45 KT GALES ARE
EXPECTED...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE LAKE. REPLACED
THE SMALL CRAFT ADVISORY FOR THE NEARSHORE WATERS WITH A GALE WATCH
FOR MONDAY. WINDS BEGIN TO COME DOWN EARLY TUESDAY AS THE LOW LIFTS
AWAY FROM THE GREAT LAKES INTO QUEBEC AND HIGH PRESSURE BEGINS TO
BUILD INTO THE WESTERN GREAT LAKES REGION. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM MONDAY.
GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-
LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...2 PM MONDAY TO 2 AM TUESDAY.
GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ868...8 PM MONDAY TO 2 AM
TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1143 PM CST SUN JAN 22 2012
.DISCUSSION...
910 PM CST
NOT MUCH CHANGE TO THE GOING FORECAST THIS EVENING. TRENDS ARE
PANNING OUT AS EXPECTED AND ARE IN A MONITOR MODE WITH THE
CONVECTION TO THE SOUTH. ACROSS THE AREA...VAD WIND PROFILE SHOW
WINDS AT 1KFT GENERALLY OUT OF THE SOUTHEAST AT 20 OR SO KT...AND
AT 3KFT...SOUTH TO SOUTHWEST AT 50 TO 55KT. MODEL PROGS SHOW THAT
THE LLJ WILL CONTINUE TO INCREASE AND WILL GIVE ANY STORMS THAT
WORK THROUGH...THE POTENTIAL BE STRONG. MID LEVEL LAPSE RATES HAD
BEEN PROGGED TO RANGE FROM 6-7.5 C/KM THIS EVE...BUT RUC ANALYSIS
SHOWED THAT BEING ON THE WANE AS OF 03Z...WITH THE HIGHEST VALUES
SHIFTING EAST. DESPITE THE SURGE OF WARMTH AND
MOISTURE...CONVECTION WILL HAVE TO STRUGGLE AGAINST A STABLE
SURFACE AIRMASS. THE BEST FOCUS STILL SET TO REMAIN SOUTH FOR
SEVERE ACTIVITY...WITH THE BEST FOCUS LOCALLY...GENERALLY EAST OF
THE I-57 CORRIDOR THROUGH THE MIDNIGHT HOUR WHERE A FEW RUMBLES OF
THUNDER MAY BE HEARD. LATEST GRIDS AND ZONES ARE OUT. SHEA
//PREV DISCUSSION...
357 PM CST
JUST 48 HOURS AFTER A WINTER STORM...THE WEATHER WILL SWING
VIGOROUSLY THE OTHER WAY ACROSS THE MIDDLE OF THE COUNTRY
TONIGHT. MUCH OF THE ATTENTION ON THE FORECAST WAS SPENT ON THE
PRESENT THROUGH MONDAY...WITH CONCERNS ON DENSE FOG...INITIAL
FREEZING DRIZZLE...CONVECTION...GUSTY WINDS...AND SOME SNOW TO
ROUND IT OUT DURING MONDAY.
SYNOPSIS...THE WELL-DEFINED UPPER LOW IS TAKING BETTER SHAPE OVER
THE CENTRAL PLAINS THIS AFTERNOON...WITH SIGNS OF A STRONG MID-
LEVEL JET AND DRY SLOT DEVELOPING INTO THE OZARKS. THE SURFACE LOW
AT 992 MB OVER EASTERN KS HAS BEEN SLIGHTLY DEEPER THAN SOME OF
THE MODELS HAD INDICATED FOR THIS AFTERNOON. THE PRIMARY SURFACE
THETA-E GRADIENT IS DRAPED FROM NORTHERN MO INTO SOUTHERN IL.
LOW-LEVEL FLOW HAS BEEN INCREASING OVER THE FORECAST AREA...WHICH
IN PLACES HAS CAUSED SOME BLOWING AND DRIFTING OF THE LIGHT AND
FLUFFY SNOW SEEN THIS PAST FRIDAY. TEMPERATURES HAVE RESPONDED TO
THE RETURN FLOW AS WELL...CLIMBING INTO THE MID 30S ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA. INCREASING SURFACE
TEMPERATURES AND DEW POINTS WILL CONTINUE INTO TONIGHT...WITH THE
PRIMARY GRADIENT MARCHING MORE QUICKLY NORTH THROUGH IL AND IN
THAN IT HAD TODAY AS CYCLOGENESIS FURTHER OCCURS. THE SURFACE LOW
WILL SHIFT NORTHEAST TO NEAR THE QUAD CITIES BY 3 AM AS THE UPPER
TROUGH BECOMES NEGATIVELY TILED. THE COLD FRONT WILL PUSH QUICKLY
FROM SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA BETWEEN 3 AM
AND 7 AM...WITH LIKELY AN AREA OF SHOWERS AND CONVECTION AHEAD OF
IT BETWEEN 10 PM AND 3 AM. THE LOW WILL THEN SHIFT ON TO THE
NORTHERN PART OF LAKE MICHIGAN BY LATE MONDAY...KEEPING WESTERLY
WINDS GUSTY HERE.
DRIZZLE/FOG/BLOWING SNOW TONIGHT...THE EXPANSION OF DRIZZLE
ACROSS THE AREA EARLY THIS AFTERNOON LINED UP WELL WITH SATURATION
AND SOME WEAK ADIABATIC OMEGA ON THE 275K AND 280K SURFACES.
CONTINUING TO LOOK AT NEAR-SURFACE LAYERS INTO TONIGHT ON THE
RUC...THE PROJECTION IS FOR THE GREATER LIFT IN SATURATION TO MOVE
NORTH OF THE AREA BY EARLY TO MID EVENING. IN ADDITION...THE
SURFACE TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING IN ALL
AREAS BY 6 PM. IN THE DIRECT PATH OF THE LOW...TOWARDS
NORTHWEST/NORTH CENTRAL IL...THE WINDS WILL ACTUALLY BEGIN TO
DECREASE WITHIN THE INFLECTION IN THE PRESSURE PATTERN. THIS MAY
ALLOW CURRENT VISIBILITY TO FURTHER REDUCE FOR SOME DENSE FOG. AT
THIS POINT HAVE JUST HIGHLIGHTED WITH AREAS OF FOG TONIGHT. EXPECT
THAT WITH THE WINDS FORECAST TONIGHT SOME OF THIS SHALLOW
BLOWING/DRIFTING WILL CONTINUE IN RURAL AREAS. WILL MENTION IN THE
FORECAST AND MONITOR CLOSELY.
THUNDERSTORM CHANCES TONIGHT...AFTER A PRECIPITABLE WATER OF ONLY
0.20 ON THE MORNING ILX SOUNDING...A SIGNIFICANT REBOUND TO NEAR
1.1 INCHES IS EXPECTED TONIGHT ACROSS CENTRAL AND EASTERN IL INTO
IN. THIS IS PART OF AN ANOMALOUSLY STRONG LOW LEVEL JET...WHICH THE
22.12 NAM HAD AT SEVEN STANDARDIZED ANOMALIES ABOVE NORMAL. THIS
STRONG WIND FIELD IS WHAT WOULD GIVE ANY THUNDERSTORMS THE CHANCE
TO BE SEVERE...COMPENSATING FOR LIMITED LOW-LEVEL
INSTABILITY/FAVORABLE LAPSE RATES. MARGINAL INSTABILITY ALOFT IS
PRESENT...AT 500-1000 J/KG IN THE FAR SOUTHEAST/...HELPED BY
STRONG DIFFERENTIAL THETA-E ADVECTION WITH THE DRY SLOT INTRUSION.
THIS OVERRIDES THE SURFACE FOCUS OF A COLD FRONT /AND POSSIBLY A
PRE-FRONTAL TROUGH JUST AHEAD OF THIS/...WHICH SHOULD HELP
CONVECTION TO DEVELOP AND EVOLVE DURING THE 7 PM TO 10 PM TIME
ACROSS SOUTHWEST INTO CENTRAL IL.
BOUNDARY LAYER DEW POINTS IN EXCESS OF 50F ARE PROJECTED BY THE
NAM/GFS TO BE NEAR THE SOUTHEAST FORECAST AREA EDGE...WHICH WILL
KEEP THE LOWER PROFILES MOIST BASED ON FORECAST SOUNDINGS. GIVEN
THE VERY CLOSE PROXIMITY OF THE SNOW COVER EDGE BASED ON THIS
MORNINGS OBSERVATIONS...EVEN HIGHER TEMPERATURE AND DEW POINTS
/BUT WITH THE SAME LOW TEMP AND DEW POINT SPREADS/ MAY BE SEEN
INTO THE SOUTHEAST FORECAST AREA. THIS SETUP WOULD FURTHER HELP
FOR WINDS TO PUNCH THE INVERSION AND MAKE IT TO THE SURFACE WITHIN
SHOWERS AND ESPECIALLY ORGANIZED THUNDERSTORMS. FORECAST NAM
SOUNDINGS AT CHAMPAIGN SHOW ALMOST 70 KTS AND 3000 FT...SO PLENTY
AVAILABLE TO MIX DOWN. THIS SETUP WILL NEED TO BE WATCHED TOO FOR
THE CHANCE OF A TORNADO AS FAR NORTH AS OUR SOUTHEAST FORECAST
AREA...AS FORECAST PROFILES AND SYNOPTICS APPROACH THOSE THAT CAN
PRODUCE COOL SEASON EPISODES.
TO THE NORTH OF THE SEVERE CONVECTIVE THREAT...RAIN SHOWERS ARE
EXPECTED WITH POTENTIAL THUNDER. SOME OF THE RAINFALL RATES COULD
BE TEMPORARILY HEAVY...WHICH COULD FURTHER AGGRAVATE RUNOFF
ALREADY HEIGHTENED FROM SNOW MELT TONIGHT.
MONDAY...THE COLD AIR ADVECTION WILL WRAP IN QUICKLY BEHIND THE
FRONT. PARAMETERS FOR GUSTY WINDS...SUCH AS STEEPENED LOW-LEVEL
LAPSE RATES AND STRONG LOW-LEVEL Q-VECTOR DIVERGENCE...ARE BEST
SEEN IN THE SOUTHERN FORECAST AREA. WIND GUSTS TO NEAR 40 MPH ARE
EXPECTED AND IT IS POSSIBLE A WIND ADVISORY WILL BE NEEDED IN
TIME. THE SOUTHERN PART OF THE OVERALL UPPER TROUGH WILL MOVE
ACROSS THE AREA...LIKELY PRODUCING SOME SNOW FOR NORTHERN AREAS.
SOME MINOR ACCUMULATION UP TO POSSIBLY AN INCH COULD OCCUR NEAR
THE STATE LINE. BY MID TO LATE AFTERNOON...DEEP NVA IS FORECAST
WHICH SHOULD END ANY LIGHT SNOW/FLURRIES. CLOUDS WILL BE SLOWER TO
CLEAR...WITH SOME STILL HOLDING ON IN NORTHERN AND EASTERN AREAS
ON TUESDAY MORNING.
BEYOND...LITTLE CHANGES MADE TO THIS PORTION OF THE
FORECAST...WHICH LOOKS RELATIVE QUIET COMPARED TO THE PAST TEN
DAYS. A BLEND OF THE BETTER PERFORMING MODELS AND THE GOING FORECAST
WAS PRUDENT AT THIS TIME.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LIFR CIG/VIS CONDITIONS...THOUGH SOME INCREASE IN VSBY WITH
HEAVIER SHRA/TSRA.
* A COUPLE PERIODS OF TSRA POSSIBLE THRU ABOUT 07-08Z...AND AGAIN
TOWARD 12Z.
* WINDS BECOMING LIGHT SSE WITH APPROACH OF SFC LOW LATE TONIGHT.
* WINDS BECOMING WEST AND GUSTING TO/ABOVE 30 KTS AT TIMES MONDAY
AFTERNOON.
* GRADUAL IMPROVEMENT IN CIG/VIS TRENDS MONDAY...THOUGH SNOW
SHOWERS POSSIBLE THROUGH MID AFTERNOON.
RATZER
//DISCUSSION...UPDATED 06Z...
RATHER COMPLICATED AVIATION WEATHER SCENARIO THROUGH MONDAY
MORNING AS STRONG LOW PRESSURE SYSTEM MOVES ACROSS THE FORECAST
AREA. LOW CIGS...REDUCED VSBY IN FOG...RA/TSRA ALL FACTORS FOR
TERMINALS THROUGH DAYBREAK.
DEEP LOW PRESSURE WAS LOCATED OVER FAR NORTHEAST MISSOURI AT
05Z...IN ASSOCIATION WITH A STRONG UPPER LEVEL DISTURBANCE LIFTING
THROUGH THE MID-MISSISSIPPI VALLEY. UNSEASONABLY WARM/MOIST AIR
CONTINUED TO SURGE NORTH INTO THE FORECAST AREA ALONG AND SOUTH OF A
WARM FRONT WHICH EXTENDED ACROSS CENTRAL/NORTHERN IL AND IND. THIS
WARM/MOIST AIR LIFTING ACROSS COLD GROUND AND SNOW COVER ACROSS
THE REGION HAS LED TO DEVELOPMENT OF EXTENSIVE IFR/LIFR STRATUS
AND FOG...AND HAS RESULTED IN SUFFICIENT ELEVATED INSTABILITY TO
PRODUCE THUNDERSTORMS AS FAR NORTH AS NORTHEAST ILLINOIS AND
SOUTHERN LAKE MICHIGAN.
SURFACE LOW IS EXPECTED TO LIFT NORTHEAST ACROSS NORTHERN ILLINOIS
THROUGH THE REMAINDER OF THE OVERNIGHT HOURS...PASSING JUST NORTH
OF CHICAGO AROUND SUNRISE. THIS WILL KEEP MUCH OF FORECAST AREA IN
VERY MOIST LOW LEVEL ENVIRONMENT THROUGH MORNING...SUPPORTING
CONTINUED LOW CIGS AND FOG. WELL-ORGANIZED AREA OF RAIN AND
EMBEDDED THUNDERSTORMS OVER EASTERN IL AND IL/IN STATE LINE REGION
AT THIS TIME SHOULD CONTINUE TO MOVE EAST/NORTHEAST OVER THE NEXT
FEW HOURS...AND MAY ACTUALLY IMPROVE VISIBILITY FOR A TIME AT TAF
SITES. AM CONCERNED HOWEVER THAT AS RAIN WEAKENS DURING THE PRE-
DAWN HOURS THAT CIGS/VIS MAY AGAIN LOWER INTO SOLID LIFR...
ESPECIALLY WITH WINDS DECREASING IN THE WEAKER PRESSURE GRADIENT
NEAR THE CENTER OF THE APPROACHING SFC LOW. ALSO...A SMALL BUT
PERSISTENT AREA OF SHRA/TSRA OVER NORTHEAST MO WITH THE UPPER LOW
CENTER WILL LIKELY LIFT NORTHEAST ACROSS FAR NORTHERN IL WITH THE
LOW THROUGH 12Z OR SO. THIS MAY BRING ANOTHER ROUND OF MORE
ISOLATED TS TO NORTHERN IL TERMINALS TOWARD MORNING.
ONCE SFC LOW PASSES EARLY MONDAY MORNING...WINDS WILL SHIFT TO THE
WEST AND BEGIN TO INCREASE...AS THE GRADIENT TIGHTENS BEHIND THE
DEPARTING LOW AND COLD ADVECTION STRENGTHENS. THIS WILL ALLOW FOR
GRADUAL IMPROVEMENT IN VIS AND CIGS TO MVFR RANGE DURING THE DAY.
ANY LINGERING LIGHT RAIN/SHOWERS WILL LIKELY CHANGE TO LIGHT SNOW
BY LATE MORNING/MIDDAY...AND MAY LAST THROUGH MID AFTERNOON OR SO
BEFORE DIMINISHING TO FLURRIES AND ENDING. STEEPENING LOW LEVEL
LAPSE RATES IN COLDER AIR COMBINED WITH STRONG PRESSURE GRADIENT
IS EXPECTED TO RESULT IN WINDY CONDITIONS MONDAY...WITH GUSTS
INCREASING TO AROUND OR JUST ABOVE 30 KTS BY MONDAY AFTERNOON.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN IFR/OCNL LIFR CONDITIONS OVERNIGHT...THOUGH
LOW CONFIDENCE IN DETAILS OF VARIABLE CIG/VIS IN SHRA/TSRA.
* MEDIUM-LOW CONFIDENCE IN ADDITIONAL TSRA THROUGH 12Z MONDAY.
* MEDIUM CONFIDENCE IN WIND DETAILS EARLY MONDAY NEAR SFC LOW CENTER.
* MEDIUM-HIGH CONFIDENCE IN IMPROVING CIG/VIS MONDAY AND GUSTY
WEST WINDS AND LIGHT SNOW SHOWERS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...SLIGHT CHANCE OF SNOW SHOWERS LATE...MAINLY VFR.
SATURDAY...VFR.
RATZER
&&
.MARINE...
240 PM CST
DEEP AREA OF LOW PRESSURE WILL LIFT NORTH ACROSS LAKE MICHIGAN
OVERNIGHT WITH STRONG SOUTHERLY WINDS AHEAD OF THE LOW BECOMING
SOUTHWEST AS THE LOW SWEEPS ACROSS THE LAKE. LOW END GALES ARE
POSSIBLE ACROSS CENTRAL PORTIONS OF THE LAKE THROUGH THIS
EVENING...AND WILL ADVECT MOIST DEWPOINTS OVER THE LAKE SETTING UP
THE POTENTIAL FOR DENSE FOG...AS WELL AS THUNDERSTORMS ACROSS THE
SOUTHERN PORTIONS OF THE LAKE. EXPECT A BRIEF LULL IN THE GALES AS
THE PRESSURE GRADIENT BECOMES MORE BAGGY NEAR THE LOW CENTER...
BEFORE STRONGER GALES RESUME MONDAY MORNING. COLD AIR SWEEPING
ACROSS THE LAKE WILL ALLOW FOR DEEP MIXING AND 40 TO 45 KT GALES ARE
EXPECTED...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE LAKE. REPLACED
THE SMALL CRAFT ADVISORY FOR THE NEARSHORE WATERS WITH A GALE WATCH
FOR MONDAY. WINDS BEGIN TO COME DOWN EARLY TUESDAY AS THE LOW LIFTS
AWAY FROM THE GREAT LAKES INTO QUEBEC AND HIGH PRESSURE BEGINS TO
BUILD INTO THE WESTERN GREAT LAKES REGION. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM MONDAY.
GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-
LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...2 PM MONDAY TO 2 AM TUESDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...8 PM MONDAY TO 4 AM TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
111 AM EST MON JAN 23 2012
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.UPDATE...
WV IMAGERY AND RUC ANALYSIS INDICATED A VIGOROUS SHRTWV MOVING INTO
WRN MO. TRENDS FROM THE 18Z MDLS AND 00Z NAM/RUC SUGGEST THAT THE
PROMINENT SHRTWV WILL SUPPORT A STRENGTHENING LOW A BIT FARTHER
SOUTH THAN PREVIOUS FCSTS. THE 00Z NAM HAS SHIFTED THE BULK OF THE
WAA/ISENTROPIC LIFT PCPN LATE TONIGHT INTO EARLY MON WELL TO THE
EAST COMPARED TO THE 18Z RUN WHILE THE 00Z RUC CONTINUES TO SUGGEST
THAT THE WAA SURGE WILL MOVE INTO CNTRL UPPER MI LATE TONIGHT BUT
WITH THE THERMAL GRADIENT ALSO SHIFTED A BIT TO THE EAST.
DIFFICULTIES HANDLING THE EXTENSIVE LINE OF CONVECTION MOVING INTO
ALSO LEADS TO GREATER UNCERTAINTY WITH THE MODELS SOLUTIONS.
SO...WITH CONFLICTING SIGNALS FROM MODEL OUTPUT...WILL NOT CHANGE
GOING HEADLINES AT THIS TIME. HOWEVER...HAVE TRIMMED ICE
ACCUMULATION AMOUNTS FOR LOCATIONS NEAR LAKE SUPERIOR AND LAKE
MICHIGAN WHERE TEMPS ARE EXPECTED TO CLIMB AOA FREEZING BY MORNING.
LARGER CHANGES MAY BE NEEDED WITH SNOW/ICE AMOUNTS LOCATION WHEN
ADDITIONAL INFORMATION IS AVAILABLE.
&&
.SHORT TERM TO 00Z TUE...
UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE ROCKIES AND A
TROUGH OFF THE SE COAST. THERE IS ALSO A SHORTWAVE TROUGH OVER THE
NORTHERN PLAINS EMBEDDED IN THE ROCKIES TROUGH WITH A POTENT
SHORTWAVE OVER THE SOUTHERN ROCKIES. THIS POTENT SHORTWAVE EVEN HAS
SOME LIGHTNING WITH IT NEAR DENVER THIS MORNING. THE TWO SHORTWAVES
WILL AFFECT THE WEATHER AND BRING WINTRY PCPN WITH THEM.
NAM SHOWS THE SOUTHERN BRANCH SYSTEM FORMING A CLOSED 500 MB LOW AND
THIS LOW HEADS NORTHEAST AND COMBINES WITH THE NORTHERN BRANCH
SHORTWAVE IN THE NORTHERN PLAINS. NAM ALSO SHOWS SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE THROUGH MONDAY WITH
ISENTROPIC LIFT AND MOISTURE ON THE I280K-I295K SURFACES AS WELL.
GFS SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE THROUGH MONDAY AS
WELL. COMPARING MODELS...00Z ECMWF AT 18Z MONDAY IS THE FURTHEST NW
WITH THE UPPER LEVEL LOW WHILE THE GFS...NAM AND CANADIAN ARE MORE
TOWARDS NE WI FOR THE 500 MB LOW PLACEMENT.
TOUGH FORECAST FOR THIS PERIOD AS TO WHAT TYPES OF PCPN WILL
FALL...WHERE IT WILL FALL AND HOW MUCH. NAM CONTINUES TO SHOW THE
CUTOFF LINE FROM SNOW WEST OF A LINE FROM MARQUETTE TO IRON
MOUNTAIN. 12Z SOUNDINGS FROM KGRB AND KAPX SHOW DRY IN THE LOW TO
MID LEVELS AND THIS HAS PREVENTED PCPN FROM REACHING THE GROUND OVER
THE CWA TODAY. THE QUESTION IS HOW LONG THIS DRY AIR STICKS AROUND.
FOR ONE THING...THE DRY AIR SHOULD TAKE ANY ABOVE ZERO TEMPERATURES
ALOFT BACK BELOW ZERO WITH WET BULB COOLING AND KEEP THE PCPN AS
SNOW OR FREEZING DRIZZLE TODAY AND NOT SLEET.
NOT REAL CONFIDENT IN THIS FORECAST AS MODELS STILL HAVE A PROBLEM
WITH HOW MUCH WARM AIR IS COMING UP AND QPF TOTALS ARE DIFFERENT AS
WELL. WENT WITH A NAM ECMWF BLEND FOR THIS FORECAST WITH MORE
WEIGHTING ON THE MORE DETAILED NAM MODEL. NAM SHOWS THE 850 MB 0C
LINE STAYING AROUND THE IMT TO MQT AREA TONIGHT INTO EARLY MONDAY
AFTERNOON. TOP DOWN SOUNDING METHOD OF FORECASTING SHOWED PCPN
STAYING MOSTLY AS SNOW ACROSS THE FAR WESTERN CWA AND THEY COULD SEE
UP TO 7 INCHES OF SNOW ON MONDAY OUT BY ONTONAGON AND IRONWOOD AND
WENT WITH A WINTER STORM WARNING THERE FOR THE SNOW AMOUNTS. HEAVIER
PCPN DOES NOT ARRIVE UNTIL AFTER 06Z TONIGHT FOR THE CWA. THERE WILL
ALSO BE SOME FREEZING RAIN THAT COULD MIX IN WITH THE SNOW THERE AS
WELL. WENT WITH AN ICE STORM WARNING FOR MARQUETTE...DICKINSON AND
MENOMINEE COUNTIES AS THE 850 MB 0C LINE IS RIGHT ACROSS THIS AREA.
LOOKED LIKE PCPN WOULD BE A BIT OF SNOW...BUT MOSTLY FREEZING RAIN
FOR TONIGHT AND ALSO FOR MONDAY MORNING. TO THE EAST...FREEZING RAIN
IS A BIT LESS FOR AMOUNTS AND WENT WITH A FREEZING RAIN ADVISORY AS
TEMPERATURES WILL BE WARMER THERE AND WILL GET ABOVE FREEZING ON
MONDAY. TO THE WEST BETWEEN THE WARNINGS...WENT WITH A WINTER
WEATHER ADVISORY FOR MIXED PCPN. NOT ENOUGH SNOW ACCUMULATIONS OR
FREEZING RAIN FOR WARNINGS...SO WINTER WEATHER ADVISORY LOOKED GOOD.
HAD ALL THE HEADLINES START AT 06Z TONIGHT. COLD AIR COMES IN ON
MONDAY AFTERNOON AND SWITCHES THE PCPN OVER TO ALL SNOW MONDAY
AFTERNOON. DID NOT CHANGE MUCH FOR TEMPERATURES AS THEY DID NOT
REALLY WARM UP TODAY. ENDED UP LOWERING HIGH TEMPERATURES A BIT
TODAY AND HAVE THE LOW TEMPERATURES TONIGHT EARLY IN THE EVENING
WITH SLOWLY RISING TEMPERATURES TONIGHT INTO MONDAY MORNING WITH A
NON-DIURNAL CURVE. QPF FROM THIS EVENT LOOKS TO BE 0.40 TO 0.67 INCH
WITH FREEZING RAIN THE MAIN PCPN TYPE OVER THE CENTRAL CWA AND SNOW
IN THE WEST. IF THE WARMER AIR MOVES A BIT FURTHER WEST...THE
HEADLINES AND FREEZING RAIN AMOUNTS WILL NEED TO BE ADJUSTED
FURTHER. ICE STORM WARNINGS AND FREEZING RAIN ADVISORIES WERE ALSO
ISSUED BECAUSE PAVEMENT TEMPERATURES WILL STILL BE BELOW FREEZING
FOR A WHILE AND EVEN IF AIR TEMPERATURES GET ABOVE FREEZING...IT
WILL FREEZE ON THE PAVEMENTS WITH BELOW FREEZING TEMPERATURES ON THE
ROAD SURFACES WHICH WOULD JUSTIFY THE ICE STORM WARNING AND FREEZING
RAIN ADVISORIES.
.LONG TERM /MONDAY NIGHT THROUGH NEXT SUNDAY/...
MONDAY NIGHT AND TUESDAY...MESSY PRECIPITATION PRODUCING SYSTEM WILL
BE ON ITS WAY OUT OF THE CWA MONDAY EVENING. HIGH POPS ALL AREAS IN
THE EVENING AS DEFORMATION PRECIP COLLAPSES FM WEST TO EAST ACROSS
CWA. SOUNDINGS INDICATE FAR EAST CWA MAY STILL BE CONTENDING WITH
RAIN EARLY IN THE EVENING...BUT SWITCHED OVR TO SNOW ALL AREAS BY
LATE EVENING. ADDITIONAL SNOW AMOUNTS AFT 00Z TUESDAY ARE KIND OF
QUESTIONABLE. DEEP MOISTURE TO H7 REMAINS ENTRENCHED OVR THE AREA
BUT LARGER SCALE UVM IS LACKING. ONSHORE WINDS MAY ENHANCE SNOW OVR
FAR WEST AND WITH H85 TEMPS DROPPING BLO -10C THERE COULD ALSO BE
LAKE ENHANCEMENT. LAKE SNOW PARAMETER IS PRETTY MUCH MAX OUT OVR
MUCH OF THE WESTERN CWA...BUT THIS IS LIKELY DUE TO ALL THE MID
LEVEL MOISTURE STILL PRESENT. BEST CHANCE FOR DECENT SNOW AMOUNTS
WILL BE IN THE FAR WEST DUE TO TERRAIN AIDED LIFTING. BLSN/DRSN WILL
BECOME ISSUE ALONG SHORELINE OF LK SUPERIOR IN THE WEST THIRD OF CWA
MUCH OF THE NIGHT DUE TO DEVELOPING GUSTY NW WINDS OVR 30 MPH. KEPT
HIGHER POPS FOR LK EFFECT OVR NW FLOW AREAS EAST OF MARQUETTE ON
TUESDAY. DEEP MOISTURE DEPARTING AND LOWERING INVERSIONS/MARGINAL
INSTABILITY SHOULD KEEP SNOW ACCUMS LIMITED ON TUESDAY. THOUGH
COOLER THAN MONDAY IN MOST AREAS...MAX TEMPS ON TUESDAY WILL STILL
BE A BIT ABOVE NORMAL.
LK EFFECT GRADUALLY DIMINISHES/ENDS TUESDAY NIGHT OVR EASTERN CWA
WITH WARMING TEMPS AT H9 AND BACKING LOW-LEVEL WINDS. WEAK SFC
RIDGE POKES INTO WESTERN INTERIOR OVERNIGHT ALONG WITH PWAT MIN.
FAVORED LOWER END OF GUIDANCE FOR TEMPS WHICH RESULTED IN MINS ZERO
TO 5 ABOVE IN THE INTERIOR SW. MAY SEE SOME MID CLOUDS STREAMING IN
AHEAD OF NEXT SYSTEM BUT OTHERWISE WEDNESDAY SHOULD BE QUIET. TEMPS
IN SOME AREAS WILL REACH ABOVE FREEZING...THIS TIME WITHOUT THE
MESSY MIX OF RAIN AND SNOW.
IN THE EXTENDED...MEDIUM RANGE MODELS IN PRETTY GOOD AGREEMENT WITH
UPPER AIR/SFC PATTERN INTO NEXT WEEKEND. GIVEN FCST OF FAIRLY FAST
WEST TO EAST PACIFIC FLOW...THE AGREEMENT IN THE MODELS LENDS HIGHER
CONFIDENCE TO THE FORECAST. MAIN SYSTEMS TO AFFECT THE UPR LAKES
REGION ARE WEDNESDAY NIGHT INTO THURSDAY THEN AGAIN FRIDAY AND
FRIDAY NIGHT. BOTH SYSTEMS ARE LACKING MOISTURE AS HIGHER PWATS
REMAIN OVR CNTRL AND SOUTHERN STATES CLOSER TO MORE ACTIVE JET
STREAM. ONLY REAL CHANCE OF SNOW WILL BE LATER WEDNESDAY NIGHT INTO
THURSDAY OVER LK SUPERIOR AND PERHAPS INTO THE EASTERN CWA. COLD AIR
IS LACKING OVR THE UPR LAKES WITH TEMPS THURSDAY AND FRIDAY FCST TO
BE ABOVE NORMAL FOR DAYTIME HIGHS AND NIGHTTIME LOWS. LACK OF COLD
AIR LEADS TO MINIMAL LK EFFECT CONCERNS AS WELL. PUT SOME POPS FOR
NW FLOW LK EFFECT IN FOR NEXT WEEKEND THOUGH AS MODELS SHOW H85
TEMPS BLO -10C IN WAKE OF TROUGH PASSING THROUGH ON FRIDAY. IN A
NUTSHELL...NO REAL SIGNIFICANT WEATHER CONCERNS ARE EXPECTED FOR THE
NEXT WEEK BEYOND THE EVENT ENDING MONDAY NIGHT.
&&
.AVIATION /FOR THE 00Z TAF ISSUANCE/...
LOW PRESSURE CURRENTLY CENTERED OVER NORTHEAST MISSOURI IS ALLOWING
MOISTURE TO FLOW INTO THE AREA PROVIDING FOR LOWER CEILINGS AS WELL
AS DECREASED VISIBILITIES AT ALL TAF SITES. SNOW SHOWERS SHOULD
BEGIN TO DEVELOP OVER CMX AND IWD BY 10Z THEREFORE HAVE INCLUDED
-SHSN IN THE TEMPO GROUP. SURFACE OBSERVATIONS UPSTREAM FROM THESE
SITES INDICATE CEILING AROUND 500FT MOVING INTO THE AREA BUT WOULD
NOT BE OUT OF THE QUESTION TO HAVE SOME LIFR CEILINGS. SURFACE OBS
ALSO INDICATE VIS IN THE IFR RANGE. HAVE KEPT A MIX OF -FZDZSN IN
THE FORECAST FOR SAW AS SOUNDINGS ARE STILL NEARLY ISOTHERMIC ALONG
THE 0 DEGREE ISOTHERM THROUGH AT LEAST 15Z. WILL HAVE TO MONITOR AS
SOME MODELS ARE HINTING THAT COLDER AIR MAY DOMINATE EARLIER
CHANGING THE PRECIP TO SNOW QUICKER THAN EXPECTED. CEILINGS NEAR
TERM FOR SAW WERE KEPT IN THE LIFR RANGE AS UPSTREAM OBS WERE AT
400-600FT AND WITH UPSLOPE FLOW FROM THE SSE VLIFR CEILINGS WOULD
NOT BE OUT OF THE QUESTION. VISIBILITIES SHOULD REMAIN IN THE IFR
RANGE.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
GALES WILL BE WINDING DOWN LATE THIS AFTERNOON OVER THE EAST HALF OF
LAKE SUPERIOR. THE PRESSURE GRADIENT WILL RELAX SOME TONIGHT INTO
MON MORNING AS THE PLAINS LOW MOVES NE TOWARD THE UPPER LAKES. AS
THE LOW MOVES ACROSS EASTERN LAKE SUPERIOR MON AFTN AND THEN INTO
ONTARIO MON NIGHT...IT APPEARS NORTHWESTERLY GALES WILL DEVELOP IN
ITS WAKE ACROSS CNTRL AND EASTERN PORTIONS OF THE LAKE. WINDS WILL
DIMINISH W TO E TUE AFTN/NIGHT WITH THE APPROACH OF A HIGH PRES
RIDGE. ALTHOUGH ANOTHER LOW PRES MAY IMPACT THE LAKE THU...NO
ADDITIONAL GALES APPEAR LIKELY ATTM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001-003-004-010-084.
FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ007-
014-085.
WINTER STORM WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR
MIZ002-009.
FREEZING RAIN ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ006-
013.
ICE STORM WARNING UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR
MIZ005-011-012.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 9 AM EST TUESDAY FOR LSZ251-267.
GALE WARNING FROM 7 PM THIS EVENING TO 9 AM EST TUESDAY FOR
LSZ243>250-264>266.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE... - NONE -
SHORT TERM...07
LONG TERM...JLA
AVIATION...KEC
MARINE...07
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1145 PM CST SUN JAN 22 2012
.DISCUSSION...
/316 PM CST SUN JAN 22 2012/
MAIN CONCERN CONTINUES TO BE THE POTENTIAL FOR SEVERE THUNDERSTORMS
OVER THE AREA THIS EVENING. MOST RECENT SURFACE ANALYSIS IS SHOWING
AN OCCLUDING SURFACE LOW OVER KANSAS WITH A WARM FRONT EXTENDING
FROM CENTRAL OKLAHOMA INTO THE MID SOUTH. TEMPERATURES AND DEWPOINTS
HAVE BEEN SLOWLY RISING OVER THE CWA TODAY AND WILL CONTINUE TO DO
SO INTO EARLY THIS EVENING AS THETA-E ADVECTION INCREASES FROM THE
SOUTH IN RESPONSE TO CENTRAL PLAINS UPPER TROUGH. STILL APPEARS
THAT SHOWERS AND THUNDERSTORMS MAY DEVELOP OVER SOUTHEAST MISSOURI
INTO SOUTHERN ILLINOIS BETWEEN 22-02Z IN AREA OF STRONG 925-850MB
MOISTURE ADVECTION. MAIN CHANCE FOR SEVERE THUNDERSTORMS WILL LIKELY
OCCUR THIS EVENING WHEN VERY STRONG/DEEP ASCENT CAUSED BY THE NEGATIVELY
TILTING MID LEVEL TROUGH WILL COINCIDE WITH MODEST INSTABILITY AND
VERY STRONG DEEP LAYER SHEAR. HRRR RUNS HAVE BEEN CONSISTENT TODAY
AND REASONABLY DEPICT A LINE OF STORMS DEVELOPING QUICKLY AROUND
02Z OVER SOUTHEASTERN MISSOURI THAT MOVES NORTHEASTWARD INTO THE
FAR EASTERN CWA BY 04Z. RUC SOUNDINGS DEPICT THAT THE LOW LEVEL
INVERSION WILL WEAKEN DURING THIS PERIOD WHICH SHOULD ALLOW FOR A
DAMAGING WIND THREAT WITH THE LINE. THERE IS ALSO SOME TORNADO
THREAT WITHIN THE LINE GIVEN 0-1KM BULK SHEAR VALUES BETWEEN
0-1KM.
PRECIPITATION WILL QUICKLY MOVE OUT OF THE AREA AFTER 06Z AS THE TROUGH/
SURFACE FRONT MOVES EAST OF THE AREA. LEFT THE CHANCE OF FLURRIES OVER
NORTHERN MISSOURI INTO WEST CENTRAL ILLINOIS LATE TONIGHT INTO LATE
MORNING MONDAY ON THE SOUTH SIDE OF THE DEEPENING UPPER LOW. THEN
EXPECT DRY WEATHER UNTIL EARLY WEDNESDAY. 12Z GFS BROUGHT STRONGER
ASCENT ALONG WITH SOME QPF UP TO I-70 DURING THE DAY WEDNESDAY.
THE 12Z NAM SUPPRESSED WITH PRECIPITATION TO THE SOUTH...MOST LIKELY
BECAUSE IT IS BRINGING A NORTHERN STREAM SHORTWAVE ACROSS THE
GREAT LAKES TOO QUICKLY. THE 18Z VERSION OF THE NAM AND THE 12Z
ECMWF FAVOR THE NORTHERN PLACEMENT. PRECIPITATION ON THE NORTHERN
FRINGE OF THIS SYSTEM WILL BE LIGHT AS THERE WILL BE STEADY DRY
AIR ADVECTING INTO IT. THIS WILL ALSO LIKELY ALLOW THE RAIN TO MIX
WITH OR CHANGEOVER TO SNOW AT TIMES AS THE WET BULB REMAINS NEAR
OR BELOW ZERO.
BRITT/KANOFSKY
&&
.AVIATION...
/1132 PM CST SUN JAN 22 2012/
COLD FRONT IS MOVING THROUGH WESTERN MISSOURI TOWARD OUR REGION.
CIGS BEHIND THE FRONT ARE BETWEEN 1000-2000FT AGL GENERALLY
SPEAKING...SO AM EXPECTING THESE CONDITIONS TO OVERSPREAD OUR
AREA. THINK LOWER IFR CIGS WILL CONTINUE TO STAY OVER NORTHEAST
MO/WEST CENTRAL IL AS THE WARM FRONT WILL LIKELY NEVER PASS
THROUGH THERE BEFORE THE COLD FRONT SWEEPS THROUGH. WIND WILL
INCREASE FROM THE WEST TO 20-30KTS. EXPECT LOW MVFR CIGS TO HANG
AROUND THROUGH THE MORNING WITH CIGS RISING AND SCATTERING DURING
THE AFTERNOON. WINDS WILL REMAIN STRONG AND GUSTY BUT SHOULD
DIMINISH BY SUNSET.
SPECIFICS FOR KSTL...
VFR CIGS WILL DROP BACK TO BETWEEN 1000-2000FT AS THE COLD FRONT
APPROACHES AROUND 10Z. WIND WILL INCREASE FROM THE WEST TO
20-30KTS BEHIND THE FRONT AND LOW-END MVFR CIGS WILL PREVAIL
THROUGH THE MORNING. SHOULD SEE CIGS LIFT ABOVE 2000FT DURING THE
EARLY AFTERNOON AND SCATTER BY SUNSET WITH DIMINISHING WINDS.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1131 PM CST Sun Jan 22 2012
...UPDATED AVIATION DISCUSSION...
.UPDATE...
/651 PM CST Sun Jan 22 2012/
A localized area of strong low-level convergence is developing close
to the surface low which is tracking across the southern KC metro at
this time. Increasing winds around 2000 ft AGL are bringing in a
surge of low-level theta-e advection, enough to bring MUCAPE values
to between 500 and 900 J/kg per latest RUC analysis. 00Z TOP sounding
shows WBZ height of only 6000 ft so small hail will be easily
attainable in the stronger cells this evening. Have already received
numerous reports of pea-size hail across southern portions of the KC
metro, with hail as large as nickel size reported in Johnson Co KS.
While hail should generally remain below severe limits, low-level
helicity values are just high enough to allow for a few rotating
updrafts in the stronger cells. Will keep a close eye on any cell
that can attain any degree of mid-level rotation as this could
enhance updraft strength enough to get hail stones approaching
quarter size.
Hawblitzel
.DISCUSSION...
Short range (Tonight through Tuesday night)...
The main focus for this time frame deals with the tonight period as
a powerful storm system moves across the region.
Per latest water vapor satellite imagery a strong PV anomaly was
digging into the Red River area of Oklahoma and Texas. A deep
surface low was positioned on the northern tip of this anomaly
through Kansas with an inverted surface trough nosing up the
Missouri River Valley through Iowa and Nebraska. Very warm
temperatures aloft allowed temperatures, despite limited mixing
depth, to climb into the upper 50s and perhaps low 60s across
southern and western portions of the forecast area. 12Z UA analysis
showed cold air poised just to our north ready to spill into the
area as the system shifts east this evening and tonight. The system
itself appears to be digging deeper than previously thought and with
that in mind the chances for precipitation should shift south as
well. Have therefore increased POPs quite a bit across the northern
half of the forecast area and continued to taper them to slight
chance pops across our south. As the cold air spills into the region
rain/rain showers will transition into snow from northwest to east
throughout the evening. This system should be fast moving and it
looks like by the time the deepest cold air will reach most of the
forecast area, the low will have lifted away and we end up with
relatively light, wrap around precipitation. So with the far
northwest portions of the forecast area transitioning earliest, the
snow amounts in that area are expected to the highest, which is
still expected to be around an inch or less. The limited duration
of the event elsewhere will limit accumulations to just a few tenths
of inch to around half an inch and this should mainly be confined to
northern Missouri, generally along and north of highway 36.
Once this system sweeps north and east of the forecast area quiet
weather should prevail through Tuesday. There is no real surge of
cold air at the surface in the wake of this system so for areas that
did not receive any snow temperatures should climb back to above
normal values with readings in the low to mid 40s. Temperatures may
struggle a bit in northern Missouri due to possible snow cover and
longer presence of cloud cover limiting daytime heating.
Another system will move into the Southern Plains Tuesday night and
warm advection ahead of the system may bring small chances for
rain/showers into southern sections of the forecast area. The best
chances will remain to our south and could see future updates remove
the already low POPs entirely.
CDB
Medium range (Wednesday through Sunday)...
Operational and ensemble models continue to agree on the overall
synoptic regime through the medium range with a negative height
anomaly over the middle Rio Grande valley becoming temporarily
separated from the main northerly jet; then opening up to help form
a mean longwave trough over the eastern conus as the Hudson Bay
vortex depresses equatorward and higher amplitude ridging develops
over the northeast Pacific basin. However, several important details
regarding the depth, location, and speed at which this cutoff
feature ejects eastward lead to larger uncertainty through the
period. In general, the medium range will likely be categorized by
above average temperatures into the weekend, followed by a cooling
trend to near average temperatures (then quite possible a period of
below average at an just beyond this time frame given the
hemispheric pattern).
Recent ECMWF solutions have lacked dependable continuity and have
generally been deeper and more connected to northern stream flow
with regards to the southern cut off system. However, the 12Z EC
iteration has trended significantly towards the GFS, though remains
deeper than other models and thrusts more moisture north and
displaces the sfc high pressure over the lower Missouri River
valley. GEFS members are primarily towards the slower and more
cutoff end of the spectrum keeping the system trapped into SW Texas
longer; thus have hedged closer to the operational GFS which appears
to be a good compromise. With this thinking, have kept the forecast
area dry with moisture limited to the I-44 corridor. Forecast
thicknesses and H9-H8 temperatures would suggest high temps above
average through Friday, though selectively toned back some of the
forecast given uncertainty in cloud cover, insolation, and mixing
depth. Cooler sfc high pressure will dive southeast from western
Canada through the weekend, with the bulk of the coldest air focused
into the Great Lakes. Consensus output yielded temperatures near or
slightly above average for the end of the period, yet pattern
recognition would suggest this is too warm. However, given the
inherent uncertainty for the end of the medium range, could not
justify making major revisions as of yet.
21
&&
.AVIATION...
For the 06Z TAFs...Band of light rain/snow is showing steady
weakening as it approaches northwest Missouri. Southern edge of this
band will track very close to MCI over the next 2 hours. For now
expect precip to narrowly miss MCI so that the TAF was kept dry, but
will keep a close eye on radar trends. Any precipitation that does
impact MCI or STJ will be very light and impacts should be minimal.
Lingering stratocumulus will provide periods of MVFR cigs through the
remainder of the early morning before ceilings lift and scatter
through early afternoon. Northwesterly gusts may exceed 25 kts
overnight before steadily weakening through the day.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1130 PM CST SUN JAN 22 2012
.UPDATE...
WILL LET ADVISORY REMAIN IN EFFECT. BEST LIFT HAD SHIFTED OVER
INTO WESTERN IOWA AND EXTREME EASTERN NEBRASKA AS OF 1130 PM.
RADAR STILL SHOWED SOME AREAS OF LIGHT SNOW SHOWERS OFF TO OUR
WEST THAT WILL MOVE THROUGH DURING THE EARLY MORNING. MOST OF
THE MEASUREABLE PRECIPITATION SHOULD END BY AROUND 3 OR 4 AM.
00Z MODELS SHOWED LOW LEVEL MOISTURE BELOW 3000 FEET AGL SHOULD
LINGER UNTIL LATE MONDAY MORNING OR EARLY MONDAY AFTERNOON.
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
GENERALLY EXPECTED MVFR CEILINGS TO CONTINUE INTO MONDAY MORNING
WITH VISIBILITIES INCREASING AS THE NIGHT GOES ON AT BOTH KOFK
AND KOMA. STILL MAY HAVE SOME AREAS IFR VISIBILITIES AND CEILINGS
PRIOR TO SUNRISE...BUT STRONGEST RADAR RETURNS HAVE SHIFTED EAST.
FOR KLNK...SOME DRIER LOW LEVEL AIR HAS WORKED IN...WITH VFR
CEILINGS. THINK THERE COULD BE SOME TEMPORARY MVFR CONDITIONS AT
KLNK OVERNIGHT.
AS HIGH PRESSURE BUILDS IN FROM THE WEST MONDAY...EXPECT NORTHWEST
WINDS TO DECREASE.
MILLER
&&
PREV DISCUSSION... /ISSUED 310 PM CST SUN JAN 22 2012/
SHORT TERM...TONIGHT THROUGH WEDNESDAY.
MAIN FORECAST CHALLENGE AND CONCERN CENTERS AROUND SNOW AND
BLOWING SNOW OVERNIGHT.
STRONG MID/UPPER LEVEL TROF AXIS NOW EXTENDS ACROSS THE CENTRAL
PLAINS WITH A WEAKER SECONDARY SHORTWAVE AXIS EXTENDING ACROSS
ERN MT INTO ERN WY. AT THE SFC...LOW PRESSURE IS QUICKLY MOVING
EAST ACROSS CENTRAL KANSAS WITH AN INVERTED TROF/CDFNT EXTENDING
UP THE MISSOURI RIVER VALLEY AT 21Z. REGIONAL MOSIAC RADAR LOOP
SHOWS A WIDENING NARROW MID LEVEL FRONTOGENETICAL BAND OF LIGHT TO
MODERATE PCPN OCCURING JUST BEHIND THE BOUNDARY WITH
LIGHTER/WIDESPREAD SNOWFALL OCCURING IN BROADSCALE VERTICAL MOTION
ASSOCIATED DEFORMATION ZONE BEHIND THE FRONTOGENETIC BAND. THE DRY
SLOT OVER PORTIONS OF SOUTHEAST NEB AS EVIDENT ON SATELLITE
IMAGERY CONTINUES TO SLOWLY FILL IN THIS AFTERNOON. TEMPERATURES
AHEAD OF THE BOUNDARY HAVE JUMPED INTO THE MID TO UPPER 40S WITH
LOWER TO MID 50S IN EXTREME SOUTHEAST NEBRASKA. COLD POCKET AT
850MB IS DIRECTLY TO OUR NORTH ACROSS ERN SD PER UPPER AIR
ANALYSIS AND RUC GUIDANCE. THIS COLD POCKET WILL CONTINUE TO DRIFT
SOUTH INTO THE FORECAST AREA THROUGH EARLY EVENING...AIDING IN
QUICKLY DROPPING SFC TEMPS BELOW FREEZING BEHIND THE BOUNDARY.
PCPN WILL CONTINUE TO INCREASE FROM WEST TO EAST ACROSS THE CWA AS
THE MID/UPPER LEVEL TROF CONTINUES TO DRIFT EWD AND
BECOMES NEGATIVELY TILTED AS IT MOVES TOWARD THE MISSISSIPPI VALLEY.
FIRST PUSH IS ALREADY APPROACHING OUR FAR NWRN COUNTIES IN WELL
DEFINED MID LEVEL FRONTOGENETIC BAND EXTENDING FROM NERN NEB INTO
WRN KS. PCPN TYPE WITH THIS WILL BE TRICKY BUT AS WE LOOSE DAYLIGHT
AND ABOVE MENTIONED COLD PUSH FROM ERN SD ADVECTS DOWN...WE SHOULD
BEGIN TO TURN ANY LIQUID PCPN OVER TO SNOW RATHER QUICKLY AS WE
PROGRESS THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS. SECOND
PUSH OF LIGHT SNOW WILL COME WITH THE MORE BROADSCALE LIFT BEHIND
THE TROF IN DEFORMATION AREA. LINGERING PCPN WILL LIKELY OCCUR
AHEAD OF THE SECONDARY NRN HIGH PLAINS SHORTWAVE THROUGH THE EARLY
MONDAY MORNING HOURS.
QPF AMOUNTS ARE GENERALLY LESS THAN 0.20" IN THE NORTH AT
MOST...WITH LESS THAN 0.10" IN OUR SOUTH. GOING FORECAST HAS A
GOOD HANDLE ON SNOWFALL AMOUNTS AND CONTINUE TO THINK THAT A 1-2"
SWATH ACROSS THE NORTHERN COUNTIES WITH ABOUT 0.5" TOWARD THE I-80
CORRIDOR.
NORTHWEST WINDS WILL PICK UP BEHIND THE BOUNDARY AFTER SUNSET WITH
GUSTS NEAR 40 MPH LIKELY INTO THE OVERNIGHT. IN THE NORTH...THIS
WILL CREATE AREAS OF BLOWING SNOW AND SO GOING WINTER WEATHER
ADVISORY FOR SNOW AND BLOWING SNOW THRU 12Z STILL LOOKS GOOD. HAVE
EXPANDED THE ADVISORY SLIGHTLY SOUTH AND EAST. WITH NEAR OR LESS
THAN AN INCH OF SNOW TO THE SOUTH OF THE ADVISORY AREA...WILL HOLD
OFF ON ANY ADVISORY BUT ROADS MAY STILL BECOME SLICK WITH JUST
MINOR SNOWFALL ACCUMULATIONS.
THE SYSTEM MOVES EAST OF THE AREA ON MONDAY AND FORECAST AREA
LOOKS DRY AS WEAK UPPER RIDGING MOVES OVERHEAD. PATTERN EVOLVES
INTO A SPLIT FLOW REGIME BY TUESDAY NIGHT WITH SOUTHERN CLOSED
LOW MOVING ACROSS TEXAS AND A WEAK SHORTWAVE AXIS CROSSING THE
FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. HAVE REMOVED POPS
TUESDAY NIGHT AS SOUTHERN STREAM SYSTEM APPEARS TO BE FAR REMOVED
FROM THE FORECAST AREA TO INDUCE ANY PCPN.
KERN
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY.
PATTERN IN THE EXTENDED PERIOD BEGINS MILD AND APPEARS IT
WILL BECOME MORE NORTHWESTERLY AND COOLER TOWARD NEXT
WEEKEND...ALTHOUGH SOME QUESTION ON WHETHER IT WILL BEGIN TO
MODERATE BY DAY 7. FORECAST GENERALLY LOOKS DRY...ALTHOUGH A SMALL
PRECIP CHANCE WILL BE CARRIED IN FRIDAY PERIOD NERN ZONES. VERY
GOOD AGREEMENT EXISTED BETWEEN 12Z GFS/CMC AND 12Z/00Z ECMWF WITH A
SHORTWAVE THROUGH DRIVING A COLD FRONT ACROSS FORECAST AREA
EARLY FRIDAY. EVEN 00Z GFS ENSEMBLE MEAN WAS IN ACCORDANCE. SEVERAL
DIFFERENCES EXISTED...HOWEVER...IN EXACTLY HOW WARM WILL THURSDAY
BE...WITH CANADIAN EXCEPTIONALLY MILD...CLOSE TO +10 DEG C AT H85.
MEANWHILE 00Z ECMWF HAD FLIPPED TO A LITTLE BELOW ZERO FROM WARMER
SOLUTION YESTERDAY AND THEN BACK TO A WARMER ONE THIS MORNING. GFS
APPEARED TO BE A DECENT COMPROMISE AND COULD YIELD READINGS PER
PREVIOUS FORECAST AND LITTLE CHANGES WERE MADE. MILD TEMPERATURES
ALOFT AHEAD OF FRONT FRIDAY COULD MIX DOWN JUST AHEAD OF OR WITH
FROPA. SO ALTHOUGH MAX TEMPS WILL PROBABLY BE COOLER THAN
THURSDAY...GENERALLY LEFT HIGHS MOSTLY ABOVE 12Z MEX NUMBERS.
COOLING TREND WAS CONTINUED INTO SATURDAY AND TO SOME DEGREE INTO
SUNDAY EVEN THOUGH LATEST GFS/ECMWF SUGGESTED MODERATION BY DAY 7.
WITH UPPER FLOW STARTING NEXT WEEKEND NORTHWESTERLY...DIDN/T WANT TO
BE OVERLY OPTIMISTIC JUST YET WAITING FOR A MODERATING WAVE TO SHIFT
FLOW TO MORE WESTERLY.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR NEZ011-012-
015>018-030>034-042-043.
IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR IAZ043.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
427 AM EST MON JAN 23 2012
.SYNOPSIS...
A STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH THE GREAT LAKES
REGION TODAY WITH GUSTY WINDS AND A PERIOD OF SHOWERS. THERE
IS EVEN A CHANCE OF A THUNDERSTORM IN A FEW SPOTS AS TEMPERATURES
BRIEFLY WARM TO WELL ABOVE AVERAGE. COOLER AIR WILL FILTER BACK IN
TONIGHT INTO TUESDAY ON CONTINUED GUSTY WINDS FOLLOWING A COLD FRONT
WITH A FEW RAIN AND SNOW SHOWERS. HIGH PRESSURE WILL BUILD INTO THE
REGION WEDNESDAY WITH A DRY DAY BEFORE THE NEXT SYSTEM BRINGS A
CHANCE OF RAIN OR SNOW ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A STRONG AREA OF LOW PRESSURE WILL TRACK ACROSS THE UPPER LAKE
TODAY. THIS WILL RESULT IN ACTIVE WEATHER FOR WESTERN NEW YORK
TODAY...WITH SEVERAL FORECAST ISSUES TO CONSIDER.
FOR TODAY...THE MOST CRITICAL FORECAST CONCERN IS THE POTENTIAL FOR
STRONG WIND GUSTS. A 50 KT LOW LEVEL JET DOWN TO ABOUT 2000 FEET
WILL CONTINUE TO SPREAD EAST ACROSS THE REGION. INITIALLY...EXPECT
THIS TO ONLY MIX PARTIALLY...WITH HIGHER TERRAIN LIKELY TO SEE GUSTS
TO 40 MPH OR SO...WHILE WINDS REMAIN RELATIVELY CALM FROM BUF-ROC
NORTHWARD...WHERE THE SOUTHERLY FLOW WILL INITIALLY STRUGGLE TO MIX
DOWN. THESE CONDITIONS SHOULD PERSIST UNTIL AROUND MID-MORNING.
THE POTENTIAL FOR GUSTY WINDS WILL INCREASE LATE MORNING INTO THIS
AFTERNOON...AS THE CORE OF THE LOW LEVEL JET MOVES ACROSS THE
REGION. WHILE MODELS DIFFER A BIT ON STRENGTH AND TIMING...THE
NAM12/RUC/RGEM/GFS ALL SHOW A QUITE IMPRESSIVE LOW LEVEL JET OF 55
TO 70 KTS CROSSING THE REGION. A LINE OF SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED ALONG THIS. THE NAM12/RGEM ARE IN GENERAL SUPPORT OF
THE HRRR...ALL OF WHICH DO A FAIRLY GOOD JOB CAPTURING THIS LINE.
USING THIS GUIDANCE...EXPECT BOTH THE LLJ AND LINE OF SHOWERS WITH
EMBEDDED THUNDERSTORMS TO ENTER WESTERN NEW YORK MID TO LATE
MORNING. BY THIS TIME...EXPECT THE LINE TO BE WEAKER THAN IT IS
NOW...WITH THE LINE LIKELY TO WEAKEN ACROSS THE FINGER LAKES
REGION...AS THE LINE SPLITS INTO TWO SEGMENTS AS IT CROSSES THE CWA
EARLY AFTERNOON. BY ITS OWN RIGHT...THE STRONG FLOW ALOFT IS LIKELY
TO BRING STRONG WINDS TO HIGHER TERRAIN TODAY. IN ADDITION TO
THIS...IT WILL NOT TAKE MUCH TO MIX STRONG WINDS ALOFT DOWN WITH
THIS...AS WINDS TO 40 KTS WILL ONLY BE 1000 FT ALOFT. SO WHILE THE
LINE IS NOT LIKELY TO BE IMPRESSIVE BY SUMMER STANDARDS...IT WILL
BEAR WATCHING TODAY...AS IT MAY HELP TO BRIEFLY MIX DOWN STRONG
WINDS ALOFT...POTENTIALLY RESULTING IN DAMAGING WINDS. FOR
NOW...WILL EXPAND THE WIND ADVISORY TO INCLUDE THE NIAGARA
FRONTIER...WHERE THIS LINE MAY STILL BE ORGANIZED ENOUGH TO HELP
WINDS MIX DOWN LATE THIS MORNING AND EARLY AFTERNOON. WILL KEEP
GUSTS AT AROUND 50 MPH...AND WILL ALLOW SHORT FUSED PRODUCTS HANDLE
THE POTENTIAL FOR LOCALLY HIGHER AND/OR DAMAGING GUSTS.
BY THIS AFTERNOON...EXPECT THE LINE OF SHOWERS TO HAVE SPLIT INTO A
NORTHERN PORTION...WHICH WILL TRACK ACROSS LAKE ONTARIO...AND A
SOUTHERN PORTION...WHICH SHOULD TRACK SOUTH AND EAST OF THE CWA.
WILL HAVE TO CONTINUE TO WATCH THE NORTHERN SEGMENT FOR GUSTY
WINDS...WHILE LOCATIONS WEST OF ROCHESTER MAY ACTUALLY GET A LULL IN
THE ACTION. THE HRRR IS SUPPORTED BY NAM12/RGEM IN A PERIOD WITH
JUST SCATTERED SHOWERS BEHIND THE LLJ...BUT STILL AHEAD OF THE
SURFACE FRONT.
THE SURFACE FRONT SHOULD CROSS THE REGION THIS EVENING...WITH WINDS
SHIFTING TO THE SOUTHWEST. TODAY/S 00Z RUNS ARE STRONGER THAN LAST
NIGHT WITH THE POST FRONTAL WINDS...WITH THE NAM SHOWING A PERIOD OF
50 KTS AT 925 MB...IN A SWELL ALIGNED SW FLOW. EXPECT THIS WILL
BRING ANOTHER ROUND OF GUSTY WINDS TO THE NIAGARA FRONTIER...AND
ALONG THE IMMEDIATE LAKE ERIE SHORELINE. FOR THIS REASON...WILL
EXTEND THE WIND ADVISORY TO CAPTURE POST-FRONTAL WINDS IN THESE
LOCATIONS. THE COLD FRONT MAY BRING SOME ADDITIONAL SHOWERS AS
WELL...WITH THIS LIKELY TO BE MOST ORGANIZED EAST OF LAKE ONTARIO.
WHILE ALL THIS GOES ON...TEMPERATURES HAVE RISEN ABOVE FREEZING IN
MOST LOCATIONS...THOUGH THERE ARE A FEW SPOTS STILL NEAR THE
FREEZING MARK. TEMPERATURES WILL CONTINUE TO RISE SLOWLY THROUGH
MID-MORNING. EXPECT THE PASSAGE OF THE STRONG WINDS ALOFT TO KEY
MIXING...AND A RATHER ABRUPT RISE IN TEMPERATURES INTO THE UPPER 40S
TO LOWER 50S. TEMPERATURES WILL REMAIN QUITE WARM UNTIL THE COLD
FRONT CROSSES THIS EVENING. ANY LINGERING SHOWERS LATE TONIGHT
SHOULD CHANGE OVER TO SNOW SHOWERS. EXPECT THESE TO BE QUITE
WIDESPREAD...WITH NO ACCUMULATION.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A WEST TO SOUTHWEST FLOW OF COLDER AIR WILL BUILD ACROSS THE AREA
TUESDAY AS LOW PRESSURE TRACKS EAST ACROSS QUEBEC. SYNOPTIC MOISTURE
WRAPPING IN BEHIND THE LOW WILL BRING A CHANCE OF SNOW SHOWERS TO
THE ENTIRE AREA...AND THERE MAY BE A LIMITED RESPONSE FROM THE LAKES
WITH THE NAM NOW SHOWING COLDER AIR (AVERAGING AROUND -12C)
ADVECTING ACROSS THE AREA DURING THE AFTERNOON. THE POTENTIAL FOR
SOME LAKE ENHANCED SNOW LOOKS TO BE GREATER EAST OF LAKE ONTARIO
WHERE THE NAM SHOWS DEEPER MOISTURE...MORE FAVORABLE SNOW GROWTH AND
GREATER LAKE INDUCED INSTABILITY. SNOW ACCUMULATIONS WILL LIKELY
REMAIN UNDER ADVISORY CRITERIA...HOWEVER.
BREEZY TO WINDY CONDITIONS WILL PERSIST ON TUESDAY...ESPECIALLY
DOWNWIND OF THE LAKES WHERE AN ADDITIONAL INFLUENCE FROM FUNNELING
WILL COME INTO PLAY.
AS THE SURFACE LOW HEADS EAST TOWARD THE CANADIAN MARITIMES TUESDAY
NIGHT...A SECONDARY TROUGH WILL DROP SOUTH ACROSS NEW YORK STATE.
WEAK CONVERGENCE ALONG THIS BOUNDARY...COMBINED WITH ADDITIONAL LIFT
FROM A PASSING UPPER LEVEL TROUGH MAY GENERATE A FEW MORE SNOW
SHOWERS DURING THE FIRST HALF OF THE NIGHT...WHILE SOME LAKE
ENHANCED SNOW LINGERS EAST OF LAKE ONTARIO. DURING THE SECOND HALF
OF THE NIGHT...DRIER AIR WILL BE WORKING IN FROM THE WEST AS HIGH
PRESSURE BUILDS EAST TOWARD THE LOWER LAKES. TEMPERATURES ALOFT WILL
ALSO BEGIN TO MODERATE AS THE CORE OF THE COLDEST AIR SHIFTS EAST
INTO NORTHERN NEW ENGLAND WITH THE DEPARTING UPPER LEVEL TROUGH.
THEREAFTER...SURFACE RIDGING WILL BUILD ACROSS THE AREA WEDNESDAY
...BRINGING PROGRESSIVELY DRIER AIR. THIS WILL HELP TO END ANY
UPSLOPE/LAKE-ENHANCED SNOW SHOWERS THAT MAY LINGER EAST OF LAKE
ONTARIO DURING THE MORNING. EXPECT DRY CONDITIONS TO CONTINUE
WEDNESDAY NIGHT AS THE SURFACE HIGH CRESTS OVER NEW YORK AND
PA. SOME INCREASE IN CLOUDS IS LIKELY LATER WEDNESDAY NIGHT AS
MOISTURE BEGINS TO WORK NORTH ALONG AN INVERTED TROUGH THAT IS
FORECAST TO EXTEND NORTH FROM A DEVELOPING LOWER MISSISSIPPI VALLEY
LOW.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AFTER THE SURFACE RIDGE DRIFTS OFF THE EAST COAST WEDNESDAY NIGHT...
THE MEDIUM RANGE MODELS INDICATE THAT A DOUBLE-BARRELED LOW PRESSURE
MAY IMPACT OUR AREA LATE IN THE WORK WEEK. THE VARIOUS GUIDANCE
PACKAGES HAVE STARTED TO COME MORE IN LINE IN THEIR HANDLING OF THIS
SYSTEM WITH THE 12Z/22 CYCLE... WITH THE GFS/GEM GLOBAL AND ECMWF
NOW ALL INDICATING A NORTHERN STREAM WAVE THAT PASSES BY WELL TO OUR
NORTH ACROSS ONTARIO AND QUEBEC THURSDAY INTO FRIDAY...WHILE A MUCH
WEAKER INITIAL SOUTHERN STREAM WAVE PASSES BY WELL TO OUR SOUTH. IN
BETWEEN IS A WEAK CONNECTING TROUGH WITH ONLY VERY MEAGER ASSOCIATED
QPF SUGGESTED BY ALL THREE MODELS...THOUGH I SUSPECT THAT THIS IS
PROBABLY A LITTLE UNDERDONE. ACCORDINGLY...WILL CONTINUE TO CARRY A
ROUND OF BROADBRUSH LOW CHANCE POPS FOR THIS PERIOD...WHILE KEEPING
PTYPE AT LEAST A A RAIN/SNOW MIX OR EVEN JUST PLAIN RAIN GIVEN THE
RATHER MILD NATURE OF OUR AIRMASS.
FOLLOWING THE PASSAGE OF THIS SYSTEM...INCREASING RIDGING/DRYING
SHOULD THEN ONCE AGAIN TAKE HOLD AND BRING A RETURN TO MAINLY DRY
WEATHER FOR LATER FRIDAY AFTERNOON AND/OR FRIDAY NIGHT. AFTER
THAT...THE GFS/ECMWF BOTH SUGGEST THAT INCREASING LARGE-SCALE
TROUGHING WILL BRIEFLY DIG SOUTHEAST INTO THE GREAT LAKES AND
NORTHEAST NEXT WEEKEND. AT THE SURFACE...THIS WILL BE REFLECTED BY
THE PASSAGE OF YET ANOTHER COMPLEX AREA OF LOW PRESSURE...WITH A
POTENTIALLY MORE SIGNIFICANT SOUTHERN STREAM WAVE LARGELY MISSING
OUR AREA TO THE SOUTHEAST...WHILE A NORTHERN STREAM CLIPPER-TYPE
SYSTEM WORKS ACROSS OUR AREA...FOLLOWED BY A BRIEF SHOT OF
SEASONABLY COLDER CANADIAN AIR AND POSSIBLE LAKE EFFECT FOR SATURDAY
NIGHT AND SUNDAY. WILL COVER ALL OF THIS WITH ANOTHER ROUND OF
CHANCE POPS...WHILE BRINGING TEMPERATURES BACK TO SLIGHTLY BELOW
NORMAL LEVELS BY THE END OF THE PERIOD.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
STRONG LOW PRESSURE WILL LIFT ACROSS THE UPPER LAKES TODAY. THIS
WILL BRING SOME VERY ACTIVE WEATHER TO WESTERN AND NORTH CENTRAL
NEW YORK IN THE PROCESS...AS OUR REGION WILL INITIALLY EXPERIENCE
LOW LEVEL WIND SHEAR ISSUES BUT THAT WILL BE FOLLOWED BY GUSTY
SURFACE WINDS AND THERE WILL EVEN BE THE THREAT FOR SOME
CONVECTION.
THROUGH MID-MORNING...LLWS WILL BE THE MAIN AVIATION CONCERN.
WINDS ALOFT WILL INCREASE THROUGH MID-MORNING...WITH SHEAR LIKELY
TO GET STRONGER DURING THIS TIME. SCATTERED IFR/MFVR CIGS ARE
POSSIBLE...BUT THESE SHOULD LARGELY REMAIN ACROSS HIGHER TERRAIN.
A LINE OF SHOWERS WITH EMBEDDED THUNDERSTORMS WILL MOVE ACROSS THE
REGION MID TO LATE MORNING THROUGH EARLY AFTERNOON. THIS WILL
LIKELY BRING A COUPLE HOURS OF RAIN SHOWERS...AND POSSIBLY A
THUNDERSTORMS. SURFACE WINDS ARE ALSO LIKELY TO INCREASE WITH THIS
AS WELL.
OTHERWISE...IT MAY BE DRY FOR A GOOD PORTION OF THE AFTERNOON
BEHIND THIS FEATURE...WITH LLWS LAXING AS WINDS ALOFT MIX DOWN
BETTER.
A COLD FRONT WILL CROSS THIS EVENING...SHIFTING WINDS TO THE SW.
THIS WILL BRING ANOTHER ROUND OF GUSTY WINDS TO BUF-IAG. CIGS IN
THE WAKE OF THIS FRONT WILL DROP TO BETWEEN 1500 AND 2500 FEET FOR
THE EVENING HOURS...THEN TO IFR LEVELS OVERNIGHT.
OUTLOOK...
TUESDAY...AREAS OF MVFR IN SCT SNOW SHOWERS.
WEDNESDAY...VFR.
THURSDAY AND FRIDAY...MAINLY VFR WITH A CHANCE OF RAIN/SNOW SHOWERS.
&&
.MARINE...
EXPECT GUSTY SOUTHERLY WINDS TODAY...WITH SMALL CRAFT ADVISORIES IN
PLACE ACROSS THE REGION. THIS STILL LOOKS ON TRACK...WITH BRIEFLY
HIGHER GUSTS POSSIBLE AS A LINE OF SHOWERS AND THUNDERSTORMS MOVES
ACROSS LAKE ERIE MID AND LATE MORNING...AND ACROSS LAKE ONTARIO LATE
MORNING THROUGH THIS AFTERNOON. BRIEF PERIODS OF GUSTY WINDS TO GALE
FORCE ARE POSSIBLE IN THUNDERSTORMS.
A COLD FRONT WILL CROSS THE WATERS THIS EVENING...SHIFTING WINDS TO
THE SW. EXPECT NEAR GALE CONDITIONS ON LAKE ERIE LATE EVENING AND
OVERNIGHT...AS 925 MB WINDS INCREASE TO 50 KTS. SURFACE TEMPERATURES
BEHIND THE FRONT ARE NOT THAT COLD...WHICH WILL SOMEWHAT LIMIT
MIXING. THIS SAID...IT IS POSSIBLE THAT THE ADVISORY WILL NEED TO BE
UPGRADED TO GALES ON LAKE ERIE TONIGHT.
AFTER THIS...WINDS WILL GRADUALLY SHIFT TO THE WEST BEHIND THE
FRONT...WITH A FAIRLY PROLONGED PERIOD OF SMALL CRAFT ADVISORY CONDITIONS
EXPECTED TO LAST INTO WEDNESDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WIND ADVISORY FROM 9 AM THIS MORNING TO 7 PM EST THIS EVENING
FOR NYZ007-008.
WIND ADVISORY FROM 9 AM THIS MORNING TO 4 AM EST TUESDAY FOR
NYZ001>003-010-011.
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NYZ012>014-020-
021.
WIND ADVISORY UNTIL 4 AM EST TUESDAY FOR NYZ019-085.
MARINE...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM EST
TUESDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM
EST TUESDAY FOR LOZ030.
SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR
LOZ043>045.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 5 AM EST
WEDNESDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...TJP
LONG TERM...JJR
AVIATION...APFFEL
MARINE...APFFEL
AREA FORECAST DISCUSSION
NWS BUFFALO NY
349 AM EST MON JAN 23 2012
.SYNOPSIS...
A STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH THE GREAT LAKES
REGION TODAY WITH GUSTY WINDS AND A PERIOD OF SHOWERS. THERE
IS EVEN A CHANCE OF A THUNDERSTORM IN A FEW SPOTS AS TEMPERATURES
BRIEFLY WARM TO WELL ABOVE AVERAGE. COOLER AIR WILL FILTER BACK IN
TONIGHT INTO TUESDAY ON CONTINUED GUSTY WINDS FOLLOWING A COLD FRONT
WITH A FEW RAIN AND SNOW SHOWERS. HIGH PRESSURE WILL BUILD INTO THE
REGION WEDNESDAY WITH A DRY DAY BEFORE THE NEXT SYSTEM BRINGS A
CHANCE OF RAIN OR SNOW ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A STRONG AREA OF LOW PRESSURE WILL TRACK ACROSS THE UPPER LAKE
TODAY. THIS WILL RESULT IN ACTIVE WEATHER FOR WESTERN NEW YORK
TODAY...WITH SEVERAL FORECAST ISSUES TO CONSIDER.
FOR TODAY...THE MOST CRITICAL FORECAST CONCERN IS THE POTENTIAL FOR
STRONG WIND GUSTS. A 50 KT LOW LEVEL JET DOWN TO ABOUT 2000 FEET
WILL CONTINUE TO SPREAD EAST ACROSS THE REGION. INITIALLY...EXPECT
THIS TO ONLY MIX PARTIALLY...WITH HIGHER TERRAIN LIKELY TO SEE GUSTS
TO 40 MPH OR SO...WHILE WINDS REMAIN RELATIVELY CALM FROM BUF-ROC
NORTHWARD...WHERE THE SOUTHERLY FLOW WILL INITIALLY STRUGGLE TO MIX
DOWN. THESE CONDITIONS SHOULD PERSIST UNTIL AROUND MID-MORNING.
THE POTENTIAL FOR GUSTY WINDS WILL INCREASE LATE MORNING INTO THIS
AFTERNOON...AS THE CORE OF THE LOW LEVEL JET MOVES ACROSS THE
REGION. WHILE MODELS DIFFER A BIT ON STRENGTH AND TIMING...THE
NAM12/RUC/RGEM/GFS ALL SHOW A QUITE IMPRESSIVE LOW LEVEL JET OF 55
TO 70 KTS CROSSING THE REGION. A LINE OF SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED ALONG THIS. THE NAM12/RGEM ARE IN GENERAL SUPPORT OF
THE HRRR...ALL OF WHICH DO A FAIRLY GOOD JOB CAPTURING THIS LINE.
USING THIS GUIDANCE...EXPECT BOTH THE LLJ AND LINE OF SHOWERS WITH
EMBEDDED THUNDERSTORMS TO ENTER WESTERN NEW YORK MID TO LATE
MORNING. BY THIS TIME...EXPECT THE LINE TO BE WEAKER THAN IT IS
NOW...WITH THE LINE LIKELY TO WEAKEN ACROSS THE FINGER LAKES
REGION...AS THE LINE SPLITS INTO TWO SEGMENTS AS IT CROSSES THE CWA
EARLY AFTERNOON. BY ITS OWN RIGHT...THE STRONG FLOW ALOFT IS LIKELY
TO BRING STRONG WINDS TO HIGHER TERRAIN TODAY. IN ADDITION TO
THIS...IT WILL NOT TAKE MUCH TO MIX STRONG WINDS ALOFT DOWN WITH
THIS...AS WINDS TO 40 KTS WILL ONLY BE 1000 FT ALOFT. SO WHILE THE
LINE IS NOT LIKELY TO BE IMPRESSIVE BY SUMMER STANDARDS...IT WILL
BEAR WATCHING TODAY...AS IT MAY HELP TO BRIEFLY MIX DOWN STRONG
WINDS ALOFT...POTENTIALLY RESULTING IN DAMAGING WINDS. FOR
NOW...WILL EXPAND THE WIND ADVISORY TO INCLUDE THE NIAGARA
FRONTIER...WHERE THIS LINE MAY STILL BE ORGANIZED ENOUGH TO HELP
WINDS MIX DOWN LATE THIS MORNING AND EARLY AFTERNOON. WILL KEEP
GUSTS AT AROUND 50 MPH...AND WILL ALLOW SHORT FUSED PRODUCTS HANDLE
THE POTENTIAL FOR LOCALLY HIGHER AND/OR DAMAGING GUSTS.
BY THIS AFTERNOON...EXPECT THE LINE OF SHOWERS TO HAVE SPLIT INTO A
NORTHERN PORTION...WHICH WILL TRACK ACROSS LAKE ONTARIO...AND A
SOUTHERN PORTION...WHICH SHOULD TRACK SOUTH AND EAST OF THE CWA.
WILL HAVE TO CONTINUE TO WATCH THE NORTHERN SEGMENT FOR GUSTY
WINDS...WHILE LOCATIONS WEST OF ROCHESTER MAY ACTUALLY GET A LULL IN
THE ACTION. THE HRRR IS SUPPORTED BY NAM12/RGEM IN A PERIOD WITH
JUST SCATTERED SHOWERS BEHIND THE LLJ...BUT STILL AHEAD OF THE
SURFACE FRONT.
THE SURFACE FRONT SHOULD CROSS THE REGION THIS EVENING...WITH WINDS
SHIFTING TO THE SOUTHWEST. TODAY/S 00Z RUNS ARE STRONGER THAN LAST
NIGHT WITH THE POST FRONTAL WINDS...WITH THE NAM SHOWING A PERIOD OF
50 KTS AT 925 MB...IN A SWELL ALIGNED SW FLOW. EXPECT THIS WILL
BRING ANOTHER ROUND OF GUSTY WINDS TO THE NIAGARA FRONTIER...AND
ALONG THE IMMEDIATE LAKE ERIE SHORELINE. FOR THIS REASON...WILL
EXTEND THE WIND ADVISORY TO CAPTURE POST-FRONTAL WINDS IN THESE
LOCATIONS. THE COLD FRONT MAY BRING SOME ADDITIONAL SHOWERS AS
WELL...WITH THIS LIKELY TO BE MOST ORGANIZED EAST OF LAKE ONTARIO.
WHILE ALL THIS GOES ON...TEMPERATURES HAVE RISEN ABOVE FREEZING IN
MOST LOCATIONS...THOUGH THERE ARE A FEW SPOTS STILL NEAR THE
FREEZING MARK. TEMPERATURES WILL CONTINUE TO RISE SLOWLY THROUGH
MID-MORNING. EXPECT THE PASSAGE OF THE STRONG WINDS ALOFT TO KEY
MIXING...AND A RATHER ABRUPT RISE IN TEMPERATURES INTO THE UPPER 40S
TO LOWER 50S. TEMPERATURES WILL REMAIN QUITE WARM UNTIL THE COLD
FRONT CROSSES THIS EVENING. ANY LINGERING SHOWERS LATE TONIGHT
SHOULD CHANGE OVER TO SNOW SHOWERS. EXPECT THESE TO BE QUITE
WIDESPREAD...WITH NO ACCUMULATION.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A WEST TO SOUTHWEST FLOW OF COLDER AIR WILL BUILD ACROSS THE AREA
TUESDAY AS LOW PRESSURE TRACKS EAST ACROSS QUEBEC. SYNOPTIC MOISTURE
WRAPPING IN BEHIND THE LOW WILL BRING A CHANCE OF SNOW SHOWERS TO
THE ENTIRE AREA...AND THERE MAY BE A LIMITED RESPONSE FROM THE LAKES
WITH THE NAM NOW SHOWING COLDER AIR (AVERAGING AROUND -12C)
ADVECTING ACROSS THE AREA DURING THE AFTERNOON. THE POTENTIAL FOR
SOME LAKE ENHANCED SNOW LOOKS TO BE GREATER EAST OF LAKE ONTARIO
WHERE THE NAM SHOWS DEEPER MOISTURE...MORE FAVORABLE SNOW GROWTH AND
GREATER LAKE INDUCED INSTABILITY. SNOW ACCUMULATIONS WILL LIKELY
REMAIN UNDER ADVISORY CRITERIA...HOWEVER.
BREEZY TO WINDY CONDITIONS WILL PERSIST ON TUESDAY...ESPECIALLY
DOWNWIND OF THE LAKES WHERE AN ADDITIONAL INFLUENCE FROM FUNNELING
WILL COME INTO PLAY.
AS THE SURFACE LOW HEADS EAST TOWARD THE CANADIAN MARITIMES TUESDAY
NIGHT...A SECONDARY TROUGH WILL DROP SOUTH ACROSS NEW YORK STATE.
WEAK CONVERGENCE ALONG THIS BOUNDARY...COMBINED WITH ADDITIONAL LIFT
FROM A PASSING UPPER LEVEL TROUGH MAY GENERATE A FEW MORE SNOW
SHOWERS DURING THE FIRST HALF OF THE NIGHT...WHILE SOME LAKE
ENHANCED SNOW LINGERS EAST OF LAKE ONTARIO. DURING THE SECOND HALF
OF THE NIGHT...DRIER AIR WILL BE WORKING IN FROM THE WEST AS HIGH
PRESSURE BUILDS EAST TOWARD THE LOWER LAKES. TEMPERATURES ALOFT WILL
ALSO BEGIN TO MODERATE AS THE CORE OF THE COLDEST AIR SHIFTS EAST
INTO NORTHERN NEW ENGLAND WITH THE DEPARTING UPPER LEVEL TROUGH.
THEREAFTER...SURFACE RIDGING WILL BUILD ACROSS THE AREA WEDNESDAY
...BRINGING PROGRESSIVELY DRIER AIR. THIS WILL HELP TO END ANY
UPSLOPE/LAKE-ENHANCED SNOW SHOWERS THAT MAY LINGER EAST OF LAKE
ONTARIO DURING THE MORNING. EXPECT DRY CONDITIONS TO CONTINUE
WEDNESDAY NIGHT AS THE SURFACE HIGH CRESTS OVER NEW YORK AND
PA. SOME INCREASE IN CLOUDS IS LIKELY LATER WEDNESDAY NIGHT AS
MOISTURE BEGINS TO WORK NORTH ALONG AN INVERTED TROUGH THAT IS
FORECAST TO EXTEND NORTH FROM A DEVELOPING LOWER MISSISSIPPI VALLEY
LOW.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AFTER THE SURFACE RIDGE DRIFTS OFF THE EAST COAST WEDNESDAY NIGHT...
THE MEDIUM RANGE MODELS INDICATE THAT A DOUBLE-BARRELED LOW PRESSURE
MAY IMPACT OUR AREA LATE IN THE WORK WEEK. THE VARIOUS GUIDANCE
PACKAGES HAVE STARTED TO COME MORE IN LINE IN THEIR HANDLING OF THIS
SYSTEM WITH THE 12Z/22 CYCLE... WITH THE GFS/GEM GLOBAL AND ECMWF
NOW ALL INDICATING A NORTHERN STREAM WAVE THAT PASSES BY WELL TO OUR
NORTH ACROSS ONTARIO AND QUEBEC THURSDAY INTO FRIDAY...WHILE A MUCH
WEAKER INITIAL SOUTHERN STREAM WAVE PASSES BY WELL TO OUR SOUTH. IN
BETWEEN IS A WEAK CONNECTING TROUGH WITH ONLY VERY MEAGER ASSOCIATED
QPF SUGGESTED BY ALL THREE MODELS...THOUGH I SUSPECT THAT THIS IS
PROBABLY A LITTLE UNDERDONE. ACCORDINGLY...WILL CONTINUE TO CARRY A
ROUND OF BROADBRUSH LOW CHANCE POPS FOR THIS PERIOD...WHILE KEEPING
PTYPE AT LEAST A A RAIN/SNOW MIX OR EVEN JUST PLAIN RAIN GIVEN THE
RATHER MILD NATURE OF OUR AIRMASS.
FOLLOWING THE PASSAGE OF THIS SYSTEM...INCREASING RIDGING/DRYING
SHOULD THEN ONCE AGAIN TAKE HOLD AND BRING A RETURN TO MAINLY DRY
WEATHER FOR LATER FRIDAY AFTERNOON AND/OR FRIDAY NIGHT. AFTER
THAT...THE GFS/ECMWF BOTH SUGGEST THAT INCREASING LARGE-SCALE
TROUGHING WILL BRIEFLY DIG SOUTHEAST INTO THE GREAT LAKES AND
NORTHEAST NEXT WEEKEND. AT THE SURFACE...THIS WILL BE REFLECTED BY
THE PASSAGE OF YET ANOTHER COMPLEX AREA OF LOW PRESSURE...WITH A
POTENTIALLY MORE SIGNIFICANT SOUTHERN STREAM WAVE LARGELY MISSING
OUR AREA TO THE SOUTHEAST...WHILE A NORTHERN STREAM CLIPPER-TYPE
SYSTEM WORKS ACROSS OUR AREA...FOLLOWED BY A BRIEF SHOT OF
SEASONABLY COLDER CANADIAN AIR AND POSSIBLE LAKE EFFECT FOR SATURDAY
NIGHT AND SUNDAY. WILL COVER ALL OF THIS WITH ANOTHER ROUND OF
CHANCE POPS...WHILE BRINGING TEMPERATURES BACK TO SLIGHTLY BELOW
NORMAL LEVELS BY THE END OF THE PERIOD.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
A DEEP BUT MATURE CYCLONE FOUND OVER MISSOURI AT 04Z WILL LIFT UP
ACROSS THE UPPER GREAT LAKES ON MONDAY. THIS WILL BRING SOME VERY
ACTIVE WEATHER TO WESTERN AND NORTH CENTRAL NEW YORK IN THE
PROCESS...AS OUR REGION WILL INITIALLY EXPERIENCE LOW LEVEL WIND
SHEAR ISSUES BUT THAT WILL BE FOLLOWED BY GUSTY SURFACE WINDS AND
THERE WILL EVEN BE THE THREAT FOR SOME CONVECTION.
FOR THE REST OF THE OVERNIGHT THOUGH...THE MAIN CONCERN WILL BE THE
AFOREMENTIONED WIND SHEAR. LOW LEVEL WIND SHEAR WILL INCREASE
OVERNIGHT AND MONDAY WITH A STRONG 60-65 KNOT LOW LEVEL JET
PROPAGATING ACROSS THE REGION. THE STRONG WINDS ALOFT WILL EXTEND
DOWN VERY CLOSE TO THE SURFACE...JUST 1000-1500 FEET UP. THAT
COMBINED WITH A 5 TO 8 DEG C LOW LEVEL INVERSION WILL CREATE RAPID
CHANGES IN WIND SPEED AND DIRECTION OVER A SHORT VERTICAL DISTANCE
ON FINAL APPROACHES AND DEPARTURES. AS MENTIONED...LOW LEVEL WIND
SHEAR WILL LIKELY BE AN ISSUE THROUGH MONDAY.
OF LESSER CONCERN OVERNIGHT WILL BE SOME MVFR CIGS THAT WILL BE
SQUEEZING IN ON THE WESTERN COUNTIES. WHILE CIGS WILL LARGELY BE VFR
OVERNIGHT...MVFR CIGS WILL BE POSSIBLE AS THE NIGHT PROGRESSES WITH
SOME IFR CIGS ACROSS PARTS OF THE SRN TIER.
ON MONDAY...THINGS WILL BECOME EVEN MORE INTERESTING AS A PRE
FRONTAL TROUGH WILL CROSS THE REGION DURING THE MORNING AND MIDDAY.
THERE WILL BE THE CHANCE FOR SOME BROKEN CONVECTION WITH THIS
TROUGH...SO HAVE INCLUDED THE MENTION OF CB`S IN THE FAR WRN TAFS.
CIGS WILL ALSO DROP TO MVFR LEVELS WITH THE PASSAGE OF THIS
TROUGH...THEN A BRIEF PERIOD OF VFR CIGS ARE EXPECTED AHEAD OF THE
MAIN COLD FRONT. THIS FRONT WILL PASS EARLY IN THE EVENING.
CIGS IN THE WAKE OF THIS FRONT WILL DROP TO BETWEEN 1500 AND 2500
FEET FOR THE EVENING HOURS...THEN TO IFR LEVELS OVERNIGHT.
OUTLOOK...
TUESDAY...AREAS OF MVFR IN SCT SNOW SHOWERS.
WEDNESDAY...VFR.
THURSDAY AND FRIDAY...MAINLY VFR WITH A CHANCE OF RAIN/SNOW SHOWERS.
&&
.MARINE...
EXPECT GUSTY SOUTHERLY WINDS TODAY...WITH SMALL CRAFT ADVISORIES IN
PLACE ACROSS THE REGION. THIS STILL LOOKS ON TRACK...WITH BRIEFLY
HIGHER GUSTS POSSIBLE AS A LINE OF SHOWERS AND THUNDERSTORMS MOVES
ACROSS LAKE ERIE MID AND LATE MORNING...AND ACROSS LAKE ONTARIO LATE
MORNING THROUGH THIS AFTERNOON. BRIEF PERIODS OF GUSTY WINDS TO GALE
FORCE ARE POSSIBLE IN THUNDERSTORMS.
A COLD FRONT WILL CROSS THE WATERS THIS EVENING...SHIFTING WINDS TO
THE SW. EXPECT NEAR GALE CONDITIONS ON LAKE ERIE LATE EVENING AND
OVERNIGHT...AS 925 MB WINDS INCREASE TO 50 KTS. SURFACE TEMPERATURES
BEHIND THE FRONT ARE NOT THAT COLD...WHICH WILL SOMEWHAT LIMIT
MIXING. THIS SAID...IT IS POSSIBLE THAT THE ADVISORY WILL NEED TO BE
UPGRADED TO GALES ON LAKE ERIE TONIGHT.
AFTER THIS...WINDS WILL GRADUALLY SHIFT TO THE WEST BEHIND THE
FRONT...WITH A FAIRLY PROLONGED PERIOD OF SMALL CRAFT ADVISORY CONDITIONS
EXPECTED TO LAST INTO WEDNESDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WIND ADVISORY FROM 9 AM THIS MORNING TO 7 PM EST THIS EVENING
FOR NYZ007-008.
WIND ADVISORY FROM 9 AM THIS MORNING TO 4 AM EST TUESDAY FOR
NYZ001>003-010-011.
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NYZ012>014-020-
021.
WIND ADVISORY UNTIL 4 AM EST TUESDAY FOR NYZ019-085.
MARINE...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM EST
TUESDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM
EST TUESDAY FOR LOZ030.
SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR
LOZ043>045.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 5 AM EST
WEDNESDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...TJP
LONG TERM...JJR
AVIATION...RSH
MARINE...APFFEL
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
240 AM EST MON JAN 23 2012
.SYNOPSIS...
LOW PRESSURE OVER THE WESTERN GREAT LAKES WILL PUSH A COLD FRONT
INTO THE AREA LATE MONDAY. AHEAD OF THE FRONT...MILDER AIR
WILL ARRIVE AND BRING LIGHT RAIN AND DRIZZLE. SURFACES TONIGHT AND
EARLY MONDAY WILL LIKELY BE BELOW FREEZING SO SOME ICING IS
LIKELY. COOLER AND DRIER AIR WILL COME IN BEHIND THE FRONT MONDAY
NIGHT AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1030 PM UPDATE...
STILL SEEING SOME VERY LIGHT RETURNS ON RADAR AND THESE CONTINUE
TO BE CONFIRMED AS JUST SNOW FLURRIES PER THE SUSQUEHANNA COUNTY
911 CENTER...AND OBS HERE AT THE NWS OFFICE...SCRANTON...AND MOUNT
POCONO. LOOKING AT RUC MODEL SOUNDINGS...ON FIRST GLANCE IT LOOKS
LIKE A CLASSIC DRIZZLE SOUNDING WITH DRY AIR IN THE MID AND UPPER
LEVELS (NO ICE CRYSTALS). HOWEVER WE HAVE MOISTURE NEAR THE
SURFACE IN THE LOWEST FEW THOUSAND FEET AND WE ARE JUST COLD
ENOUGH (-5C) TO PRODUCE SOME ICE CRYSTALS FOR FLURRIES. AFTER 06Z
WE SHOULD WARM ENOUGH JUST ABOVE THE SURFACE TO CHANGE ANY PRECIP
OVER TO DRIZZLE. WITH SURFACE TEMPS BELOW FREEZING THROUGH
DAYBREAK...AREAS OF FREEZING DRIZZLE IN THE CURRENT FREEZING RAIN
ADVISORY AREA LOOKS ON TRACK. HIGHEST PROBABILITY FOR SOME LIGHT
ICE ACCUMS WILL BE ACROSS THE HIGHER TERRAIN OF NEPA AND THE
WESTERN CATSKILLS. BASED ON LAV GUIDANCE SHOWING KAVP NEAR
FREEZING THROUGH 13Z AND MONTICELLO THROUGH 15Z...EXTENDED THE END
TIME FROM 8 AM TO 11 AM.
ONE LAST THING...OUTSIDE OF THE ADVISORY AREA I STILL THINK THAT
SOME PATCHY FREEZING DRIZZLE IS POSSIBLE ACROSS
CHEMUNG...TIOGA...BROOME...AND SOUTHERN CHENANGO
COUNTIES...ESPECIALLY THE HIGHER UP IN ELEVATION YOU LIVE. CHOSE NOT
TO EXPAND THE ADVISORY BECAUSE THE SOUTHEAST FLOW MAY BE JUST
ENOUGH OF A DOWN SLOPING FACTOR TO LIMIT THE IMPACT OF ANY
FREEZING DRIZZLE. THE OVERNIGHT SHIFT WILL HAVE TO MONITOR THE
RADAR TRENDS JUST TO BE SAFE. THE PREVIOUS AFD IS BELOW...
7 PM UPDATE...AN INTERESTING DEVELOPMENT OVER THE LAST
HOUR OR SO AS THE KBGM RADAR HAS SHOWN SOME VERY LIGHT RETURNS
OVER NORTHERN PA SNEAKING INTO THE SOUTHERN TIER OF NY. THIS IS
CONFIRMED BY WILLIAMSPORT REPORTING VERY LIGHT SNOW AT LAST OB.
OUR HIGHLY SENSITIVE WEB CAM AT THE OFFICE IS SHOWING VERY LIGHT
AND BRIEF PRECIPITATION...BUT WHEN YOU STEP OUTSIDE YOU HAVE TO
STARE AT THE PARKING LOT LIGHTS FOR AT LEAST A MINUTE BEFORE YOU
SEE ANYTHING. WE MAY BE SEEING A FEW FLURRIES ATTM (RUC SOUNDINGS
SHOWING -5C IN THE MOIST LAYER)...BUT IF TRENDS CONTINUE TO
INCREASE AND IT BECOMES MORE APPARENT THAT IT IS FREEING DRIZZLE
THE ADVISORY IN PLACE MAY HAVE TO BE EXPANDED NORTHWEST. FOR NOW
WILL HOLD WITH THE GOING FORECAST AND WILL MONITOR TRENDS TO SEE
IF THIS VERY FINE DRIZZLE OR AREA OF FLURRIES PICKS UP IN
INTENSITY BECAUSE RIGHT NOW IT IS JUST TOO LIGHT TO HAVE AN
IMPACT. THE PREVIOUS AFD IS BELOW...
MARINE LYR HAS SLOWLY BEEN CREEPING NWRD THIS MRNG. ADVANCE
SHD ACCELERATE THIS EVE WITH THE LOSS OF THE SUN AND TIGHTENING OF
THE GRADIENT AHD OF THE LOW. THIS SHALLOW LYR WILL BE THE MOISTURE
SOURCE FOR ANY FREEZING RAIN AND DRIZZLE OVERNIGHT AS MOISTURE AHD
OF THE FNT IS STILL SVRL HRS AWAY. MODELS CONT TO BE VERY LGT WITH
THE QPF...REALLY JUST A FEW HUNDREDTHS AT MOST. CRNT AREA OF THE
ADVISORY DOES SHOW THE BEST AREA WELL SO WILL LEAVE AS IS EVEN
THOUGH IT LOOKS LIKE ICING WILL BE VERY LGT. TEMPS HAVE REALLY
STRUGGLED TO RISE DESPITE THE HAZY SUN...ALONG WITH DEW PTS STILL
IN THE TEENS AND EVEN SINGLE NUMBERS. THERE/S PTNL FOR THE TEMPS
TO DROP A FEW HRS AFT DARK...ESP OVER THE WRN CATS. NAM CONTS TO
SHOW A GOOD DAMMING SIGNITURE...SO...ANY PCPN THAT DOES FALL WILL
CERTAINLY FREEZE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
FAST MVG OCCLUSION PASSES THRU MON ARND 18Z WITH SHWRS AND GUSTY
WINDS...ALTHOUGH DEEP INV SHD HELP KEEP THE HIGHEST WINDS ABV THE
SFC...SO NO WIND FLAGS NEEDED. CAA DOES NOT REALLY BEGIN UNTIL
LTR MON NGT AND WITH THE MODIFIED AIR...POST FNTL TEMPS STILL ABV
NRML ON TUE. SW FLOW WILL ALSO KEEP ANY WEAK LE CONFINED TO THE
XTRM NORTH...IF AT ALL. SO...MUCH OF THE FCST AREA WILL ENJOY ABV
NRML TEMPS WITH GUSTY WINDS INTO TUE.
UPR TROF AXIS PASSES EARLY WED WHICH WILL BE FLWD BY BRIEF RISING
HGTS AND MILDER AIR ON WED. ANOTHER WEAK WV APRCHS LATE IN THE
PD...BUT WITH LTL IF ANY PCPN.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
230 AM MON UPDATE... NO SIG CHANGES MADE TO THE CURRENT EXTENDED
GRIDS...AS THE INCOMING 00Z MON GUIDANCE IS CONSISTENT...FOR THE
MOST PART...FROM ITS PREVIOUS RUNS.
THE BIGGEST UNCERTAINTY REMAINS WITH THE SRN STREAM LOW OVER TX LATER
THIS WEEK...AND HOW THIS SYSTEM EVOLVES TWDS NEXT WEEKEND. AS
MENTIONED BELOW IN THE PREV DISC...MODEL DISCREPANCY CONTS WITH
THIS PATN. THE EC CONTINUES TO BE THE MOST AGGRESSIVE...BRINGING
PCPN (LIKELY SOME KIND OF MIXED PTYPES...GIVEN THE INITIAL LACK OF
MUCH COLD AIR) FARTHER NWD...WHILE THE GFS IS MORE SUPPRESSED/PROGRESSIVE.
BOTH MODELS WOULD SUGGEST A TREND TWDS COLDER WX BY NEXT
SUN/MON...WITH THE GFS BEING THE COLDEST SOLUTION.
AGAIN...GIVEN LACK OF CONFIDENCE FROM ABT FRI ONWARD...WE SIMPLY
STUCK WITH CONTINUITY/PREV SET OF GRIDS.
PREV DISC... MODELS ARE IN FAIR AGREEMENT WITH MEDIUM RANGE WHICH
INCLUDES TWO NORTHERN STREAM SFC TROFS AND A FAIRLY SIGNIFICANT
SOUTHERN STREAM SYSTEM PASSING TO OUR SOUTH. OVERALL TEMPS WILL
RANGE 5 TO 10 DEGREES ABOVE NORMAL AS WE RESIDE IN THE
CLIMATOLOGICAL COLDEST PERIOD OF THE WINTER SEASON.
WEDNESDAY NIGHT WILL BE DRY WITH SFC HIGH PRES IN THE AREA.
ON THURSDAY, SFC LOW PRES IN THE UPPER GREAT LAKES MAY PRODUCE
SOME MIXED WINTRY PRECIP DURING THE MORNING BEFORE TEMPS WARM
ENOUGH FOR JUST PLAIN RAIN. SYSTEM IS NOT VERY STRONG WITH
LIMITED MOISTURE THEREFORE JUST LOW CHC POPS. THURSDAY NIGHT THE
TRAILING COLD FRONT WILL PUSH THROUGH WITH CHC POPS FOR MIXED
RAIN/SNOW SHOWERS CHANGING TO ALL SNOW SHOWERS. ON FRIDAY SOME
LINGERING POST FRONTAL SNOW SHOWERS ARE POSSIBLE DURING THE
MORNING OTHERWISE DRY.
FRIDAY NIGHT THROUGH SATURDAY, A SOUTHERN STREAM LOW PRES SYSTEM
LIFTS FROM THE GULF STATES INTO THE MID ATLANTIC REGION THEN OFF
THE COAST. THE ECMWF BRINGS THIS FEATURE FURTHER NORTH SPREADING
PRECIP ACROSS THE ENTIRE CWA WHILE THE GFS IS MUCH FURTHER SOUTH
WITH NO IMPACT HERE. WILL FOLLOW HPC GUIDANCE WHICH HAS CHC POPS
NE PA FRIDAY NIGHT THEN CHC POPS ENTIRE FA ON SATURDAY. FOR NOW
THE COLUMN LOOKS COLD ENOUGH FOR PRIMARILY ALL SNOW, BUT THERE
COULD BE A RAIN/SNOW MIX SATURDAY MIDDAY OVER FAR SOUTHERN FA.
BEHIND THIS SYSTEM A NORTHERN STREAM SFC TROF WILL PASS THROUGH
THE REGION SATURDAY NIGHT WITH CHC POPS FOR SNOW SHOWERS. ON
SUNDAY A COLDER AIRMASS ALONG WITH WESTERLY FLOW WILL CONTINUE CHC
POPS FOR SNOW SHOWERS ESPECIALLY NRN CWA.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
UPDATED AS OF 1250 AM MON... LOWER CIGS HAVE OVERSPREAD NE PA AND
MOST OF CNY ATTM...AND SHOULD PERSIST THROUGHOUT THE VALID TAF PD.
THUS...LOOK FOR MVFR RESTRICTIONS TO BE PREVALENT. AT KBGM AND
KITH...IFR CIGS COULD OCCASIONALLY SNEAK IN EARLY THIS MRNG.
PATCHY DZ/FZDZ IS LIKELY OVER THE HILLS TO THE E AND SE OF KAVP
AND KBGM THIS MRNG...BUT WE DON`T EXPECT THIS ACTIVITY TO PRESENT
MUCH OF AN IMPACT AT THE TERMINAL SITES THEMSELVES.
A RELATIVELY BRIEF PD OF STEADY RAIN IS ANTICIPATED LATER THIS
AFTN INTO THE EARLY EVE (GENERALLY 21-03Z). ONCE AGN...KBGM/KITH
WILL BE THE MOST LIKELY CANDIDATES FOR PERIODIC IFR.
PERHAPS THE MOST SIG AVIATION ISSUE TODAY WILL BE LLWS. SE WINDS
NEAR THE SFC GENERALLY 5-15 KT...WILL BE TOPPED BY VERY STG FLOW
OF 45-60 KT FROM THE SW...JUST ABV THE SFC LYR (BASICALLY
1500-2500 FT AGL). THESE SHEAR CONDS ARE VERY LIKELY TO PERSIST A
GOOD PTN OF THE DAY...LIKELY NOT ABATING TIL LATER IN THE AFTN (18-21Z).
.OUTLOOK...
TUE/WED...PATCHY MVFR CNTRL NY...MAINLY VFR NE PA.
THU/FRI...MVFR IN RAIN/SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR
PAZ038>040-043-044-047-048-072.
NY...FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ057-
062.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/HEDEN
SHORT TERM...DGM
LONG TERM...MLJ/RRM
AVIATION...HEDEN/MLJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1258 AM EST MON JAN 23 2012
.SYNOPSIS...
LOW PRESSURE OVER THE WESTERN GREAT LAKES WILL PUSH A COLD FRONT
INTO THE AREA LATE MONDAY. AHEAD OF THE FRONT...MILDER AIR
WILL ARRIVE AND BRING LIGHT RAIN AND DRIZZLE. SURFACES TONIGHT AND
EARLY MONDAY WILL LIKELY BE BELOW FREEZING SO SOME ICING IS
LIKELY. COOLER AND DRIER AIR WILL COME IN BEHIND THE FRONT MONDAY
NIGHT AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1030 PM UPDATE...
STILL SEEING SOME VERY LIGHT RETURNS ON RADAR AND THESE CONTINUE
TO BE CONFIRMED AS JUST SNOW FLURRIES PER THE SUSQUEHANNA COUNTY
911 CENTER...AND OBS HERE AT THE NWS OFFICE...SCRANTON...AND MOUNT
POCONO. LOOKING AT RUC MODEL SOUNDINGS...ON FIRST GLANCE IT LOOKS
LIKE A CLASSIC DRIZZLE SOUNDING WITH DRY AIR IN THE MID AND UPPER
LEVELS (NO ICE CRYSTALS). HOWEVER WE HAVE MOISTURE NEAR THE
SURFACE IN THE LOWEST FEW THOUSAND FEET AND WE ARE JUST COLD
ENOUGH (-5C) TO PRODUCE SOME ICE CRYSTALS FOR FLURRIES. AFTER 06Z
WE SHOULD WARM ENOUGH JUST ABOVE THE SURFACE TO CHANGE ANY PRECIP
OVER TO DRIZZLE. WITH SURFACE TEMPS BELOW FREEZING THROUGH
DAYBREAK...AREAS OF FREEZING DRIZZLE IN THE CURRENT FREEZING RAIN
ADVISORY AREA LOOKS ON TRACK. HIGHEST PROBABILITY FOR SOME LIGHT
ICE ACCUMS WILL BE ACROSS THE HIGHER TERRAIN OF NEPA AND THE
WESTERN CATSKILLS. BASED ON LAV GUIDANCE SHOWING KAVP NEAR
FREEZING THROUGH 13Z AND MONTICELLO THROUGH 15Z...EXTENDED THE END
TIME FROM 8 AM TO 11 AM.
ONE LAST THING...OUTSIDE OF THE ADVISORY AREA I STILL THINK THAT
SOME PATCHY FREEZING DRIZZLE IS POSSIBLE ACROSS
CHEMUNG...TIOGA...BROOME...AND SOUTHERN CHENANGO
COUNTIES...ESPECIALLY THE HIGHER UP IN ELEVATION YOU LIVE. CHOSE NOT
TO EXPAND THE ADVISORY BECAUSE THE SOUTHEAST FLOW MAY BE JUST
ENOUGH OF A DOWN SLOPING FACTOR TO LIMIT THE IMPACT OF ANY
FREEZING DRIZZLE. THE OVERNIGHT SHIFT WILL HAVE TO MONITOR THE
RADAR TRENDS JUST TO BE SAFE. THE PREVIOUS AFD IS BELOW...
7 PM UPDATE...AN INTERESTING DEVELOPMENT OVER THE LAST
HOUR OR SO AS THE KBGM RADAR HAS SHOWN SOME VERY LIGHT RETURNS
OVER NORTHERN PA SNEAKING INTO THE SOUTHERN TIER OF NY. THIS IS
CONFIRMED BY WILLIAMSPORT REPORTING VERY LIGHT SNOW AT LAST OB.
OUR HIGHLY SENSITIVE WEB CAM AT THE OFFICE IS SHOWING VERY LIGHT
AND BRIEF PRECIPITATION...BUT WHEN YOU STEP OUTSIDE YOU HAVE TO
STARE AT THE PARKING LOT LIGHTS FOR AT LEAST A MINUTE BEFORE YOU
SEE ANYTHING. WE MAY BE SEEING A FEW FLURRIES ATTM (RUC SOUNDINGS
SHOWING -5C IN THE MOIST LAYER)...BUT IF TRENDS CONTINUE TO
INCREASE AND IT BECOMES MORE APPARENT THAT IT IS FREEING DRIZZLE
THE ADVISORY IN PLACE MAY HAVE TO BE EXPANDED NORTHWEST. FOR NOW
WILL HOLD WITH THE GOING FORECAST AND WILL MONITOR TRENDS TO SEE
IF THIS VERY FINE DRIZZLE OR AREA OF FLURRIES PICKS UP IN
INTENSITY BECAUSE RIGHT NOW IT IS JUST TOO LIGHT TO HAVE AN
IMPACT. THE PREVIOUS AFD IS BELOW...
MARINE LYR HAS SLOWLY BEEN CREEPING NWRD THIS MRNG. ADVANCE
SHD ACCELERATE THIS EVE WITH THE LOSS OF THE SUN AND TIGHTENING OF
THE GRADIENT AHD OF THE LOW. THIS SHALLOW LYR WILL BE THE MOISTURE
SOURCE FOR ANY FREEZING RAIN AND DRIZZLE OVERNIGHT AS MOISTURE AHD
OF THE FNT IS STILL SVRL HRS AWAY. MODELS CONT TO BE VERY LGT WITH
THE QPF...REALLY JUST A FEW HUNDREDTHS AT MOST. CRNT AREA OF THE
ADVISORY DOES SHOW THE BEST AREA WELL SO WILL LEAVE AS IS EVEN
THOUGH IT LOOKS LIKE ICING WILL BE VERY LGT. TEMPS HAVE REALLY
STRUGGLED TO RISE DESPITE THE HAZY SUN...ALONG WITH DEW PTS STILL
IN THE TEENS AND EVEN SINGLE NUMBERS. THERE/S PTNL FOR THE TEMPS
TO DROP A FEW HRS AFT DARK...ESP OVER THE WRN CATS. NAM CONTS TO
SHOW A GOOD DAMMING SIGNITURE...SO...ANY PCPN THAT DOES FALL WILL
CERTAINLY FREEZE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
FAST MVG OCCLUSION PASSES THRU MON ARND 18Z WITH SHWRS AND GUSTY
WINDS...ALTHOUGH DEEP INV SHD HELP KEEP THE HIGHEST WINDS ABV THE
SFC...SO NO WIND FLAGS NEEDED. CAA DOES NOT REALLY BEGIN UNTIL
LTR MON NGT AND WITH THE MODIFIED AIR...POST FNTL TEMPS STILL ABV
NRML ON TUE. SW FLOW WILL ALSO KEEP ANY WEAK LE CONFINED TO THE
XTRM NORTH...IF AT ALL. SO...MUCH OF THE FCST AREA WILL ENJOY ABV
NRML TEMPS WITH GUSTY WINDS INTO TUE.
UPR TROF AXIS PASSES EARLY WED WHICH WILL BE FLWD BY BRIEF RISING
HGTS AND MILDER AIR ON WED. ANOTHER WEAK WV APRCHS LATE IN THE
PD...BUT WITH LTL IF ANY PCPN.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE IN FAIR AGREEMENT WITH MEDIUM RANGE WHICH INCLUDES TWO
NORTHERN STREAM SFC TROFS AND A FAIRLY SIGNIFICANT SOUTHERN
STREAM SYSTEM THAT PASSING TO OUR SOUTH. OVERALL TEMPS WILL RANGE
5 TO 10 DEGREES ABOVE NORMAL AS WE RESIDE IN THE CLIMATOLOGICAL
COLDEST PERIOD OF THE WINTER SEASON.
WEDNESDAY NIGHT WILL BE DRY WITH SFC HIGH PRES IN THE AREA.
ON THURSDAY, SFC LOW PRES IN THE UPPER GREAT LAKES MAY PRODUCE
SOME MIXED WINTRY PRECIP DURING THE MORNING BEFORE TEMPS WARM
ENOUGH FOR JUST PLAIN RAIN. SYSTEM IS NOT VERY STRONG WITH
LIMITED MOISTURE THEREFORE JUST LOW CHC POPS. THURSDAY NIGHT THE
TRAILING COLD FRONT WILL PUSH THROUGH WITH CHC POPS FOR MIXED
RAIN/SNOW SHOWERS CHANGING TO ALL SNOW SHOWERS. ON FRIDAY SOME
LINGERING POST FRONTAL SNOW SHOWERS ARE POSSIBLE DURING THE
MORNING OTHERWISE DRY.
FRIDAY NIGHT THROUGH SATURDAY, A SOUTHERN STREAM LOW PRES SYSTEM
LIFTS FROM THE GULF STATES INTO THE MID ATLANTIC REGION THEN OFF
THE COAST. THE ECMWF BRINGS THIS FEATURE FURTHER NORTH SPREADING
PRECIP ACROSS THE ENTIRE CWA WHILE THE GFS IS MUCH FURTHER SOUTH
WITH NO IMPACT HERE. WILL FOLLOW HPC GUIDANCE WHICH HAS CHC POPS
NE PA FRIDAY NIGHT THEN CHC POPS ENTIRE FA ON SATURDAY. FOR NOW
THE COLUMN LOOKS COLD ENOUGH FOR PRIMARILY ALL SNOW, BUT THERE
COULD BE A RAIN/SNOW MIX SATURDAY MIDDAY OVER FAR SOUTHERN FA.
BEHIND THIS SYSTEM A NORTHERN STREAM SFC TROF WILL PASS THROUGH
THE REGION SATURDAY NIGHT WITH CHC POPS FOR SNOW SHOWERS. ON
SUNDAY A COLDER AIRMASS ALONG WITH WESTERLY FLOW WILL CONTINUE CHC
POPS FOR SNOW SHOWERS ESPECIALLY NRN CWA.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
UPDATED AS OF 1250 AM MON... LOWER CIGS HAVE OVERSPREAD NE PA AND
MOST OF CNY ATTM...AND SHOULD PERSIST THROUGHOUT THE VALID TAF PD.
THUS...LOOK FOR MVFR RESTRICTIONS TO BE PREVALENT. AT KBGM AND
KITH...IFR CIGS COULD OCCASIONALLY SNEAK IN EARLY THIS MRNG.
PATCHY DZ/FZDZ IS LIKELY OVER THE HILLS TO THE E AND SE OF KAVP
AND KBGM THIS MRNG...BUT WE DON`T EXPECT THIS ACTIVITY TO PRESENT
MUCH OF AN IMPACT AT THE TERMINAL SITES THEMSELVES.
A RELATIVELY BRIEF PD OF STEADY RAIN IS ANTICIPATED LATER THIS
AFTN INTO THE EARLY EVE (GENERALLY 21-03Z). ONCE AGN...KBGM/KITH
WILL BE THE MOST LIKELY CANDIDATES FOR PERIODIC IFR.
PERHAPS THE MOST SIG AVIATION ISSUE TODAY WILL BE LLWS. SE WINDS
NEAR THE SFC GENERALLY 5-15 KT...WILL BE TOPPED BY VERY STG FLOW
OF 45-60 KT FROM THE SW...JUST ABV THE SFC LYR (BASICALLY
1500-2500 FT AGL). THESE SHEAR CONDS ARE VERY LIKELY TO PERSIST A
GOOD PTN OF THE DAY...LIKELY NOT ABATING TIL LATER IN THE AFTN (18-21Z).
.OUTLOOK...
TUE/WED...PATCHY MVFR CNTRL NY...MAINLY VFR NE PA.
THU/FRI...MVFR IN RAIN/SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR
PAZ038>040-043-044-047-048-072.
NY...FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ057-
062.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/HEDEN
SHORT TERM...DGM
LONG TERM...RRM
AVIATION...HEDEN/MLJ
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1058 PM CST SUN JAN 22 2012
.DISCUSSION.../ISSUED AT 735 PM CST/
A COMBINATION OF FACTORS HAS DECREASED THE HAZARDOUS WINTER WEATHER
THREAT FOR MUCH OF THE AREA...NAMELY WEST AND NORTH. LESSER SUPPORT
FOR SNOW ESPECIALLY ANYTHING BEYOND QUITE LIGHT SNOW SEEMS OBVIOUS.
SLIGHTLY LESSER WINDS THAN EARLIER EXPECTED ALONG WITH TEMPERATURES
AND EVEN DEWPOINTS GOING TO FREEZING OR ABOVE EARLY THIS EVENING IN
THE SOUTHWEST WHERE THE STRONGEST WINDS HAVE BEEN BLOWING ALL MEAN
THAT A WINTER WX ADVISORY SEEMS NO LONGER NEEDED. HOWEVER THE SYSTEM
IS TAKING BETTER DEFINITION IN OUR SOUTHEAST AREA INCLUDING
NORTHWEST IOWA SO WILL KEEP THE ADVISORY THERE...AND FOR NOW WILL
KEEP THROUGH NOON MONDAY ALTHOUGH NOT SURE IF BLOWING SNOW WILL BE
BAD ENOUGH.ASIDE FROM THAT BIT OF WARMING WITH THE MIXING
TEMPERATURES NOT TOO BAD...MAY WIND UP SLIGHTLY LESS COLD BUT WILL
CERTAINLY FALL TOWARD MORNING. AMOUNTS IN REMAINING ADVISORY AREA
SHOULD BE 2 TO 3 INCHES BUT THERE COULD BE SOME PLACES WITH A BIT
MORE. / WILLIAMS
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
MVFR-IFR CONDITIONS WITH AREAS OF SNOW WILL CONTINUE THROUGH THE
OVERNIGHT...AS LEADING BAND OF HEAVIER SNOW MOVES THROUGH FAR
EASTERN PARTS OF THE AREA...AND OCCASIONAL LIGHTER SNOW FOLLOWS
BEHIND. CONDITIONS EXPECTED TO GRADUALLY IMPROVE WEST TO EAST AFTER
10Z-12Z...WITH VFR CONDITIONS EXPECTED MOST AREAS BY LATE MONDAY
AFTERNOON. NORTHWEST WINDS OCCASIONALLY GUSTING 25-30KTS INTO JAMES
VALLEY AS OF 05Z AND WILL CONTINUE TO EXPAND EAST THROUGH THE
OVERNIGHT HOURS...ADDING TO VISIBILITY REDUCTION IN BLOWING SNOW.
THIS SHOULD ABATE AS WINDS DECREASE IN THE LATE MORNING/AFTERNOON
MONDAY.
&&
.PREV DISCUSSION.../ISSUED AT 336 PM CST/
CHALLENGE IS AT HIGH LEVEL WITH SYSTEM IN THE SHORT TERM...DEALING
WITH A HEALTHY SPLIT FLOW. WATER VAPOR IMAGERY SHOWING FULL LATITUDE
TROUGH PUSH ACROSS THE CENTRAL U.S...WITH SEVERAL PIECES OF ENERGY.
FIRST HAS MOVED PAST AND INTO NORTHWEST MN...SECOND IS LIFTING
THROUGH CENTRAL NEBRASKA...AND THIRD /THE STRONGEST/ LIFTING AROUND
THE BASE IN SOUTHERN KS. THE LATTER WILL DRIVE INTENSE CYCLOGENESIS
WELL EAST OF THE AREA LATER TONIGHT AND MONDAY WITH ITS OWN IMPACT
BEING WINDS...BUT FOCUS WILL BE ON THE MID FEATURE FOR THE EVENING.
LEADING BOUNDARY/INVERTED TROUGH NOW SHIFTED TO NEAR A KRWF TO KSUX
LINE...AND COLLAPSING SOUTHEAST AS ENERGY IN SOUTHERN TROUGH LIFTS
NORTHWARD. TEMPS AHEAD ACROSS NORTHWEST IOWA AREA ALL AT OR ABOVE
FREEZING NOW...WITH THE ONLY AREA STILL HAVING SOME PATCHY FREEZING
DRIZZLE FAR EASTERN SECTIONS OF SW MN AROUND KMWM/KMJQ/KOTG.
SNOWFALL ACROSS MUCH OF THE STATE OTHER THAN THE FAR SOUTHEAST AT
MID AFTERNOON...IN BROAD DIV Q ASSOCIATED WITH THE TROUGH.
PRECIPITATION IS ALSO BREAKING OUT ALONG THE LEADING PV SUPPORT
THROUGH NEBRASKA INTO SOUTHEAST SOUTH DAKOTA. EARLIER MINOR WARM
NOTCH NOTED ON MORNING RAOBS HAS APPARENTLY BEEN WORKED OUT
WITH PRECIPITATION ALL SNOW AT YANKTON PER LATEST WEBCAM IMAGE.
SHORT RANGE MODELS FAIL ON QPF BEING IN THE RIGHT PLACE...BUT HAVE
LESSER PROBLEMS WITH THE DYNAMICS IN MOST...ESPECIALLY IN PLACEMENT
OF THE SIGNIFICANT PV FEATURES. CLOSELY FOLLOWED RUC/NAM ON
THESE...AND RESULT WAS A QUICKER EASTWARD DEVELOPMENT ALONG THE PV
ADVECTION. QUICK PEEK AT LATEST HRRR WOULD SUGGEST THE PROGRESSION
MAY BE EVEN GREATER...AS WILL BE DEMISE OF THE WESTERN SNOW AREA IN
FAVOR OF THIS DEVELOPMENT ACROSS NEBRASKA.
THERMODYNAMICALLY...THIS IS FAR FROM THE MOST EFFICIENT PROFILE WITH
MUCH OF THE LOWER PROFILES IN THE -5 TO -8C RANGE...AND THE LIFT
FAIRLY HIGH. DENDRITIC DEPTH IS LESS THAN 100 HPA...AND REALLY DO
NOT NOTE ANY SIGNIFICANT INSTABILITY TO MAKE USE OF UNTIL MID TO
LATE EVENING WITH SOME APPEARING ABOVE OF MID LEVEL FRONT...SO LOOKS
MORE OF A BROAD AND LESSER FOCUSED EVENT UNTIL BAND DEVELOPS TOWARD
THE EAST. HOWEVER...FAIRLY QUICK PERIOD OF DYNAMIC/THERMODYNAMIC
OVERLAP...SO ANY ENHANCEMENT SHOULD BE SOMEWHAT SHORT TERM...BUT
COULD GET A LITTLE TIME BOOST BY THE SLOWING OF FEATURES DURING MID
LEVEL DEVELOPMENT TO EAST. IMPACT OVERALL WAS TO LOWER SNOWFALL
AMOUNTS BY AN INCH OR SO WEST...AND RAISE BY A HALF INCH TO INCH IN
THE EAST. WHILE MOST...IF NOT ALL OF THE AREA IS LIKELY TO STAY AT
OR BELOW SNOWFALL CRITERIA FOR AN ADVISORY... IT WILL BE THE
COMBINATION OF THE SNOW AND BLOWING SNOW THAT SUPPORTS THE ADVISORY.
THIS INCLUDES AREAS FARTHER EASTWARD WHICH RECEIVED SOME HEAVIER
SNOWFALL IN LAST EVENT. MAIN PUSH OF WINDS LOOKS TO GET GOING IN
THE FAR WEST LATE AFTERNOON TO EARLY EVENING...TOWARD THE I29
CORRIDOR TOWARD MIDNIGHT...SW MN BETWEEN 06Z AND 09Z. APPEARS THAT
GUSTY 20 TO 35 MPH WIND CAN BE EXPECTED AFTER INITIAL PRESSURE RISE
SURGE...AND MORE TYPICAL THROUGH THE EAST BY MONDAY AS THE CYCLONE
STRENGTHENS TO THE EAST. CONTINUED CURRENT ADVISORY...BUT DID EXTEND
THE END TIME TO COVER THE STRONGER WINDS. ADDITIONAL AREA WAS ADDED
OVER THE REMAINDER OF THE AREA FOR THE SNOW/WIND THREAT...BUT
STARTED AS ONE GROUP RATHER THAN PIECEMEAL TO KEEP IT SIMPLE...AND
TO PICK UP ANY LINGERING FREEZING DRIZZLE IN THE FAR EAST.
ON MONDAY...CONDITIONS WILL IMPROVE SOMEWHAT OUTSIDE ANY LINGERING
SNOWFALL WHICH IS LIMITED TO THE FAR EASTERN AREA AS UPPER LOW
DEVELOPS TO THE EAST. THIS DEVELOPMENT WILL KEEP THE GRADIENT
HOLDING ON STRONG THROUGH SW MN AND INTO NW IA THROUGH AT LEAST
MIDDAY IF NOT MID AFTERNOON. FOR THIS REASON...CONTINUED ADVISORY TO
COVER THE BLOWING SNOW POTENTIAL IN THE EASTERN GROUP. TEMPERATURES
LIKELY TO STRUGGLE WITH FRESH SNOW AND MIXED START...SO DO NOT LOOK
FOR MORE THAN A 4-6 DEGREE CLIMB AS SURFACE RIDGE FROM WEST FINALLY
STARTS TO DROP OFF THE WINDS IN THE WEST DURING THE AFTERNOON.
/CHAPMAN
BRISK NORTHWEST WINDS TAPER OFF BY MONDAY NIGHT...AS THE LOW MOVES
WELL EAST OF THE FORECAST AREA AND ARCTIC HIGH PRESSURE SLIPS INTO
THE REGION. WITH A FRESH SNOWPACK...MOSTLY CLEAR SKIES AND WINDS
BECOMING LIGHT...TEMPERATURES SHOULD PLUMMET OVERNIGHT. CONTINUED TO
GO WELL BELOW GUIDANCE WHICH IS NOTORIOUS FOR BEING TOO WARM IN
THESE EVENTS. LOWS SHOULD FALL INTO THE LOWER TEENS AND SINGLE
DIGITS BELOW ZERO.
HIGH PRESSURE SHIFTS EASTWARD ON TUESDAY WHILE THE UPPER FLOW
BECOMES MORE ZONAL. MODEST WARM AIR ADVECTION WILL ALLOW
TEMPERATURES TO IMPROVE INTO THE 20S TO LOWER 30S. A WEAK UPPER
LEVEL WAVE SLIDES THROUGH THE REGION TUESDAY NIGHT WITH LITTLE
IMPACT OTHER THAN AN INCREASE IN CLOUDS.
THE MILDER PATTERN CONTINUE INTO FRIDAY WITH WEST AND SOUTHWEST
WINDS AND LOW LEVEL TEMPERATURES NEAR OR ABOVE FREEZING. EVEN WITH
925 MB TEMPERATURES AS WARM AS +6 OR +8C...IT WILL BE DIFFICULT TO
MIX TO THE SURFACE WITH THE RECENT SNOWPACK IN PLACE. HOWEVER...DO
EXPECT HIGHS TO RISE BACK ABOVE AVERAGE AND HOVER IN THE LOWER TO
MID 30S FOR MUCH OF THE FORECAST AREA. AGAIN...WENT A BIT BELOW
GUIDANCE NUMBERS DURING THE PERIOD WITH THIS IN MIND. A MID LEVEL
WAVE SLIPS ACROSS THE MISSOURI RIVER AREA THURSDAY NIGHT AND EARLY
FRIDAY WITH MEAGER MOISTURE AND LIFT. COULD SQUEEZE OUT A LITTLE
LIGHT PRECIPITATION ACROSS THE SOUTH SO WILL LEAVE MENTION OF A
SLIGHT CHANCE. A REINFORCING SHOT OF COOLER AIR WILL FOLLOW FRIDAY
NIGHT AND SATURDAY WITH BRISK NORTHWEST WINDS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR
IAZ001>003-012>014-020>022-031-032.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR
MNZ080-081-089-090.
NE...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR
NEZ013-014.
SD...WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR
SDZ070-071.
&&
$$
WILLIAMS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
333 AM CST MON JAN 23 2012
.SYNOPSIS...WINTER WX ADVISORY WL REMAIN INTACT WITH THIS
ISSUANCE. MIXED PRECIPITATION CHANGING TO SNOW AND THEN ENDING
FROM SOUTHWEST TO NORTHEAST TODAY.
SPLIT FLOW WL DOMINATE THE CONUS FOR MUCH OF THE WEEK. BY NEXT
WEEKEND...RISING HEIGHTS OUT NR THE WEST COAST WL CAUSE THE
DOWNSTREAM FLOW TO CONSOLIDATE AGAIN...WITH BROAD TROF FORMING
OVER CEN/ERN NOAM.
MOST SIG PCPN EVENT WL BE WITH CYCLONE CROSSING THE RGN TDA...THEN
A PERIOD OF RELATIVELY QUIET WX EXPECTED AS THE FCST AREA IS
DOMINATED BY LOW-AMPLITUDE NRN STREAM THE REST OF THE WEEK. TEMPS
WL REMAIN ABV NORMAL MOST OF THE WK...THEN DROP BACK CLOSE TO
NORMAL AS BROAD UPR TROF DEVELOPS OVER THE FCST AREA NEXT WEEKEND.
&&
.SHORT TERM...TDA/TNGT/TUE. CYCLONE WL LIFT NEWD ACRS THE FCST
AREA THIS MORNING. DEEPENING MOISTURE...MID-LVL COOLING DUE TO
ASCENT...AND EVENTUALLY COLDER AIR WRAPPING ARND THE CYCLONE WL
RESULT IN DZ/FZDZ/RN CHANGING TO SN FM W TO E DURING THE DAY. THIS
WAS STARTING TO HAPPEN QUICKLY OVER WRN PARTS OF WI THIS MORNING.
SOUNDINGS CONSTRUCTED OFF RUC ANALYSES SUGGEST MUCH OF CENTRAL AND
N-C WL GO OVER TO SNOW ONCE BAND OF HEAVIER PCPN ARRIVES FROM THE
S. N-C WI AND PORTIONS OF NE WI WL NEED ADVISORY ALL DAY DUE TO
THE SNOW. NOT SURE SNOWFALLS WL JUSTIFY KEEPING ADVISORY GOING ALL
DAY OVER CENTRAL WI. BUT SNOW FALLING ON ICY ROADS WON/T BE
GOOD...SO TRAVEL CONDITIONS MAY REMAIN POOR. PLAN TO KEEP HEADLINE
INTACT WITH THE ISSUANCE AND JUST CANCEL EARLY IF/WHEN CONDITIONS
IMPROVE.
DENSE FOG COULD BE AN ISSUE IN THE E...ESP ALONG THE TRACKLINE OF
THE SFC LOW WHERE WINDS WL GO LGT FOR A TIME AS THE LOW CROSSES
THE AREA. BUT BAND OF HEAVIER PCPN THAT DEVELOPED DURING THE PAST
1-2 HRS WL WORK ACRS THIS AREA...HELPING TO MIX THE LOWER ATM.
SFC WINDS WERE ALSO LOSING THE SELY TRAJECTORY THAT WAS FEEDING
HIGHER DWPTS INTO THE AREA. BEST COURSE OF ACTION SEEM TO BE TO
GO WITH AREAS OF DENSE FOG IN THE GRIDS/ZONES...BUT FOREGO
ADVISORY SINCE IT DOESN/T APPEAR LOW VSBYS WL BE WIDESPREAD ENOUGH
TO WARRANT AN ADVISORY.
TRAJECTORIES LOOK FAVORABLE FOR SOME LAKE-EFFECT IN NORTH-CENTRAL
WI THIS AFTN INTO EARLY EVENING. LAKE SURFACE/AIR TEMPERATURE
DIFFERENCE SOMEWHAT MARGINAL...BUT PLENTY OF MOISTURE LINGERING FM
DEPARTING SYSTEM MAY OFFSET THAT. OTHER THAN THE LAKE-EFFECT...
PCPN SHOULD DIMINISH MOST AREAS BY EARLY EVENING.
CLDS LIKELY TO LINGER TNGT...WITH THE BEST CHC FOR BREAKS IN THE
TYPICAL NW-FLOW DOWNSLOPE AREA OVER THE NE.
HIGH TEMPS WL OCCUR EARLY TDA...FOLLOWED BY SLOWLY FALLING TEMPS.
BUT THE AIR BEHIND THE SYSTEM ISN/T REAL COLD...SO LINGERING
MOISTURE ON ROADWAYS SHOULD HAVE A CHC TO EVAPORATE BEFORE CAN
FREEZE. EDGED MINS UP A BIT TNGT...THEN WENT WITH BLEND OF BEST
PERFORMING GUID FOR MAXES TUE.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY.
THE UPPER FLOW WILL BE TRANSITIONING OVER THE PERIOD FROM A FAST
ZONAL PATTERN...TO BUCKLED NORTHWEST FLOW. AS A RESULT...MILD
PACIFIC DOMINATED AIRMASSES THROUGH THE END OF THIS WEEK WILL RETURN
TO THE POLAR VARIETY. A COUPLE OF MINOR SYSTEMS TO DEAL WITH
THROUGH THE EXTENDED. SIMILAR TO LAST NIGHT PREFER THE GFS FOR THE
SHORTWAVE LATE WEDNESDAY NIGHT INTO THURSDAY WITH THE FAST FLOW IN
PLACE. THEREAFTER...A CLIPPER SYSTEM WILL ARRIVE ON SATURDAY WHICH
WILL BE THE LEADING EDGE OF ARCTIC AIR. BOTH THE GFS AND ECMWF
HANDLE THIS FEATURE COMPARABLY...SO WILL BLEND THE TWO SOLUTIONS.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...WEAK SHEARED SHORTWAVE
WILL BE CROSSING THE REGION LATE TUESDAY NIGHT INTO EARLY WEDNESDAY
MORNING. MID AND HIGH CLOUDS WILL BE ON THE INCREASE TUESDAY NIGHT
AHEAD OF THE WAVE...BUT LOW LEVELS STRUGGLE TO SATURATE. SUPPOSE
THERE COULD BE A FLURRY OR TWO OUT OF THE MID-DECK BUT THATS MORE OF
A SHORT TERM CONCERN SO WILL LEAVE THE FORECAST DRY. SKIES WILL BE
CLEARING ON WEDNESDAY AS THE FIRST SHORTWAVE DEPARTS. HIGHS WILL BE
MILD WITHIN A PACIFIC AIRMASS WITH READINGS AROUND THE FREEZING
MARK. CLOUDS WILL BE ON THE INCREASE AGAIN WEDNESDAY NIGHT AHEAD OF
A MORE DYNAMIC SHORTWAVE. NOT SEEING THE GOOD MID-LEVEL LAPSE RATES
LIKE LAST NIGHT...BUT MID AND UPPER FORCING IS DECENT. STILL
LOOKING AT DRY WEDGES HOWEVER IN THE LOW AND MID-LEVELS WITH
MOISTURE PROFILES FAILING TO SATURATE. WILL AGAIN TREAT THIS AS A
SHORT TERM CONCERN AND REMOVE POPS.
REST OF THE FORECAST...THE SHORTWAVE TROUGH WILL FINISH CROSSING THE
REGION THURSDAY MORNING AND WILL AGAIN REMOVE THE SLIGHT CHANCE OF
PRECIP. SHOULD SEE SOME SUN MOVE IN FOR THE AFTERNOON WITH TEMPS
SLIGHTLY ABOVE FREEZING. NORTHWEST FLOW ALOFT WILL BE STRENGTHENING
THURSDAY NIGHT INTO FRIDAY...WHEN WILL HAVE WEAK COLD ADVECTION AND
BREEZY CONDITIONS OVER THE PERIOD...BUT NO PRECIP THREAT OF
SIGNIFICANCE. RATHER STRONG SHORTWAVE WILL BE MOVING ACROSS THE
REGION FRIDAY NIGHT...WHICH WILL BE THE LEADING EDGE OF AN ARCTIC
AIRMASS. TEMPERATURES WILL FALL BACK TO OR BELOW NORMAL WHILE WINDS
WILL BE PRETTY BRISK. CAN ENVISION OCCASIONAL SNOW FLURRIES OR
LIGHT SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY AS THE UPPER TROUGH
SWINGS OVERHEAD. CURRENT FORECAST IS DRY...BUT WILL JUST MENTION TO
LATER SHIFTS. COLD AND DRY CONDITIONS ON SUNDAY...AND POSSIBLY SOME
LIGHT SNOW ON MONDAY AS ANOTHER CLIPPER SYSTEM MOVES THROUGH THE
REGION.
&&
.AVIATION...FOR 12Z TAF ISSUANCE...LIFR/VLIFR CONDITIONS
WIDESPREAD ACRS THE AREA THIS MORNING. CONDITIONS SHOULD START TO
IMPROVE LATER TDA ONCE THE LOW PULLS OFF TO THE NE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ005-
010>013-018>021-030-031-035>037-045.
&&
$$
SKOWRONSKI/MPC
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
242 AM CST MON JAN 23 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
NEGATIVE TILTED MID LEVEL/UPPER LEVEL TROUGH WILL MOVE ACROSS
WISCONSIN THIS MORNING BECOMING MORE OF A CLOSED LOW BY NOON...THEN
NORTH TOWARDS LAKE SUPERIOR THIS EVENING.
SURFACE LOW IS RATHER BROAD BUT THE CENTER SHOULD MOVE ACROSS
SOUTHEAST WISCONSIN THIS MORNING AND TO CENTRAL LAKE MICHIGAN BY
NOON...THEN NEAR LAKE HURON THIS EVENING. HIGHEST QPF OFF TO THE
SOUTHEAST AND EAST WITH SOME ELEVATED CAPE EARLY THIS MORNING
THICKNESS/BOUNDARY LAYER TEMPERATURES INDICATING MOST OF THE
PRECIPITATION LIQUID EXCEPT FOR A CHANGEOVER TO SNOW AROUND 6 AM
POSSIBLE WELL WEST OF MADISON. RUC SOUNDINGS PREFERRED OVER THE
COLDER NAM. THIS WOULD KEEP LIQUID AT MADISON UNTIL MID MORNING AND
OVER MILWAUKEE TOWARDS NOON.
MAIN CONCERN IS STILL WITH FREEZING RAIN POTENTIAL. SURFACE
TEMPERATURES ARE ALL ABOVE FREEZING EXCEPT IN AREAS TOWARDS THE
DELLS AND MARQUETTE COUNTY. OTHER PROBLEM IS WITH COLD ROAD
TEMPERATURES AND THE RAIN WASHING OFF THE RESIDUAL SALT...STILL SOME
SLIPPERY ROADS IN AREAS WITH TEMPERATURES IN THE MID 30S.
SOME DENSE FOG POTENTIAL EARLY THIS MORNING UNDER THE SURFACE LOW.
LIGHT ACCUMULATIONS OF SNOW EXPECTED WITH THE CHANGEOVER...UP TO AN
INCH. THIS MAINLY AS UPPER LOW MOVES ACROSS. TIGHT GRADIENT AROUND
THE LOW MAY GENERATE SOME PRETTY GUSTY WINDS...POTENTIALLY INTO THE
30-35 MPH RANGE LATER THIS AFTERNOON.
.TUESDAY THROUGH SUNDAY...FORECAST CONFIDENCE...MEDIUM
FAIRLY QUIET WEATHER EXPECTED THROUGH THE REMAINDER OF THE WORK WEEK
AND INTO THE WEEKEND.
HIGH PRESSURE ON TUESDAY WILL BRING DECREASING CLOUDS WITH NEAR
NORMAL HIGH TEMPERATURES.
A PAIR OF WEAK WAVES TO ZIP THROUGH ZONAL FLOW WEDNESDAY AND
THURSDAY. NOT SEEING ENOUGH MOISTURE AND LIFT TO INCLUDE MENTION OF
POPS...THOUGH ONE OF THESE WAVES MAY SQUEEZE OUT A FEW FLURRIES.
ABOVE NORMAL TEMPS IN THE LOW TO MID 30S EXPECTED UNDER THE ZONAL
FLOW FOR MID WEEK.
ONE MORE DAY OF ABOVE NORMAL TEMPS FRIDAY WILL BE FOLLOWED BY
COLDER...BUT STILL NEAR NORMAL TEMPS FOR THE WEEKEND AS AN UPPER
TROUGH MOVES INTO THE GREAT LAKES. NOTHING IN THE MODELS AT THIS
TIME TO INCLUDE POPS FOR THE WEEKEND.
&&
.AVIATION/12Z TAFS/...WIDESPREAD LIFR CEILINGS/VSBYS WITH PLENTIFUL
LOW LEVEL MOISTURE AHEAD OF APPROACHING SURFACE LOW THAT SHOULD MOVE
ACROSS SOUTHEAST WISCONSIN THIS MORNING. ONCE LOW MOVES TO CENTRAL
LAKE MICHIGAN BY NOON...EXPECT COLD AIR ADVECTION TO GRADUALLY
CHANGE PRECIP OVER TO LIGHT SNOW. EXPECTING MINOR ACCUMULATIONS...AN
INCH OR LESS. WEST WINDS WILL BECOME RATHER GUSTY THIS AFTERNOON
WITH TIGHT GRADIENT AROUND STRONG DEPARTING LOW CENTER. CEILINGS
AND VSBYS WILL GRADUALLY RISE TO MVFR LATER THIS AFTERNOON AS THE
LOW PULLS AWAY. MVFR CIGS AND VFR VSBYS EXPECTED TONIGHT.
&&
.MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH MIDDAY TUESDAY
AS STRONG LOW PRESSURE REACHES CENTRAL LAKE MICHIGAN BY NOON. WINDS
WILL DIMINISH FOR A TIME UNDER THE LOW CENTER...BUT WILL INCREASE
AGAIN BEHIND A COLD FRONT EARLY THIS AFTERNOON AS WINDS BECOME
SOUTHWEST AND EVENTUALLY NORTHWEST. A FEW GALE GUSTS POSSIBLE....
ESPECIALLY LATE THIS AFTERNOON INTO THIS EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ051-052-
058>060-063>066-068>072.
DENSE FOG ADVISORY UNTIL 7 AM CST THIS MORNING FOR WIZ062-067.
WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ046-
047-056-057.
LM...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR LMZ643>646.
SMALL CRAFT ADVISORY UNTIL NOON CST TUESDAY FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...DDV
AREA FORECAST DISCUSSION
NWS ALBANY NY
1057 AM EST MON JAN 23 2012
.SYNOPSIS...
AFTER SOME LIGHT ICING CONDITIONS THIS MORNING...TEMPERATURES
WILL CLIMB ABOVE FREEZING THIS AFTERNOON FOR MAINLY RAIN SHOWERS
THAT WILL ACCOMPANY THE FRONTAL BOUNDARY. SOMEWHAT COOLER AIR WILL
FILTER IN FOR TUESDAY WITH SOME LAKE EFFECT SNOW DOWNWIND OF LAKE
ONTARIO. TRANQUIL CONDITIONS FOR THE MID WEEK AS A RIDGE OF HIGH
PRESSURE TRACKS ACROSS THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 11 AM EST...HAVE DROPPED FREEZING RAIN ADVISORY FOR THE MID
HUDSON VALLEY REGION...WHERE TEMPS HAVE WARMED ABOVE FREEZING.
ELSEWHERE...HAVE KEPT FREEZING RAIN ADVISORIES IN PLACE...ALTHOUGH
TEMPS NOW RISING TO NEAR OR ABOVE FREEZING ACROSS THE EASTERN
CATSKILLS...SCHOHARIE VALLEY...AND THE CAPITAL REGION.
FURTHER N AND E...COLD AIR HANGING TOUGH...FROM SE VT INTO THE
BERKSHIRES AND SOUTH INTO EASTERN LITCHFIELD COUNTY...WHERE
DRIZZLE PERSISTS. WE MAY NEED TO EXTEND THE ADVISORIES FOR
PORTIONS OF THESE AREAS...AS COLD AIR MAY REMAIN TOUGH TO
DISLODGE.
STEADIER RAIN SHOULD DEVELOP FROM W TO E DURING THE MID TO LATE
AFTERNOON HOURS. THERE IS SOME POSSIBILITY THAT POCKETS OF
SUBFREEZING TEMPS PERSIST IN PORTIONS OF SE VT AND/OR THE
BERKSHIRES WHEN THIS ARRIVES...SO WILL NEED TO MONITOR CLOSELY.
PREVIOUS DISCUSSION FOLLOWS...
AS OF 6 AM...DRIZZLE IS BEGINNING TO SHOW UP ACROSS THE TRI-STATE
REGION AND MID-HUDSON VALLEY INCLUDING OUR RADAR IN VCP31.
TEMPERATURES VARY BUT THEY DO HOVER AROUND THE FREEZING MARK WHERE
DRIZZLE IS BEING REPORTED. NCEP MODEL SUITE ALONG WITH THE
RUC13/HRRR NOT DOING THAT WELL...HOWEVER...THEY DO SUGGEST THIS
AREA OF DRIZZLE AND SATURATING BOUNDARY LAYER ADVANCES SLOWLY
NORTH THIS MORNING. WET BULB PROFILES ARE STILL BELOW FREEZING SO
WE WILL CONTINUE WITH THE ADVISORY AND REFRESH THE GRIDS AND
HOURLY TEMPS/DEWPTS. PER THE 06Z MOS AND HOURLY LAV/LAMP...MOST
AREAS WILL CLIMB ABOVE FREEZING AROUND THE NOON HOUR.
PREV DISC...
VERY CHALLENGING NEAR TERM FORECAST AS FZDZ HAS NOT
MATERIALIZED AT THIS TIME. PER METARS...THE CIGS REMAIN RATHER
HIGH AND DEWPOINT DEPRESSIONS ARE 5 DEGREES OR GREATER. WE DID
RECEIVE A REPORT OF FLURRIES IN LITCHFIELD COUNTY AND THIS CAN
ALSO BE CONFIRMED WITH SEVERAL METARS ACROSS THE NYC METRO AREA
REPORTING LIGHT SNOW. THIS MAY BE DUE TO THE OCEANIC EFFECT ADDING
ENOUGH NUCLEI TO RESULT IN THOSE OBS OF LIGHT SNOW. THE FORECAST
SOUNDINGS ACROSS OUR REGION STILL SUGGEST THE BOUNDARY LAYER WILL
MOISTEN UP BELOW THE -10C ISOTHERM INCLUDING THE SHEAR PROFILES
FOR SOME DRIZZLE FORMATION. RUC13 FORECAST SOUNDINGS DELAY THE
ONSET OF MOISTURE UNTIL THE 12-15Z TIME FRAME. BY THAT
TIME...TEMPERATURES ARE BEGINNING TO CLIMB TO AT OR ABOVE FREEZING
ALONG AND SOUTH OF I90. THE COLDER AIR IS EXPECTED TO REMAIN IN
PLACE LONGER ACROSS THE DACKS...LAKE GEORGE SARATOGA REGION AND
SOUTHERN VERMONT UNTIL ABOUT THE NOON HOUR. THE ADVISORY LOOKS
GOOD AT THIS TIME WITH NO CHANGES EXPECTED.
POTENT SHORT WAVE TRACKING NORTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY INTO THE GREAT LAKES REGION WILL SEND A COLD FRONT EASTWARD
THIS AFTERNOON. A BAND OF BKN SHOWERS IS EXPECTED AND WE WILL
PLACE CATEGORICAL POPS FOR THE ENTIRE REGION. TIMING OF THIS FRONT
APPEARS TO BE AOA 21Z. AS FOR CONVECTIVE POTENTIAL /IE
THUNDER/...THE SHOWALTER INDEX IS EXPECTED TO DROP TOWARD 0C FOR
PORTIONS OF THE REGION WITH THE BEST UPPER SUPPORT FOR THE WESTERN
MOHAWK VALLEY AND DACKS. WHILE WE WILL NOT INCLUDE THUNDER...WOULD
NOT TOTALLY RULE OUT A RUMBLE OF THUNDER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
WITH FROPA...DRY SLOT QUICKLY APPROACHES THIS EARLY EVENING. SOME
LINGERING UPSLOPE SHOWERS ARE EXPECTED BUT THIS TOO SHOULD
DECREASE THROUGH TONIGHT. SEEMS THE INITIAL COLD ADVECTION WILL
REMAIN WEST OF THE HUDSON RIVER VALLEY WITH TEMPERATURES OVERNIGHT
REMAINING ABOVE FREEZING FOR A GOOD PORTION OF THE REGION. THE
EXCEPTION TO THIS WILL BE FOR PORTIONS OF THE DACKS. LAKE ONTARIO
CONTRIBUTION INCREASES A BIT...ALBEIT MARGINALLY...TO WARRANT
CHANCE POPS FOR RAIN/SNOW SHOWERS TRANSITIONING TO SNOW SHOWER
OVERNIGHT.
DUE TO A RELATIVELY MILDER START TO THE DAY TUESDAY...TEMPERATURES
FOR THE REGION SHOULD ONCE AGAIN CLIMB ABOVE THE FREEZING WITH MID
40S EXPECTED FOR THE MID HUDSON RIVER VALLEY AND NW CT. CYCLONIC
FLOW REMAINS OVER LAKE ONTARIO AND THE DACKS WITH A VEERING WIND
PROFILE TO TAKE WHAT BANDS OF LAKE EFFECT ACTIVITY FURTHER SOUTH.
SECONDARY COLD FRONT IS EXPECTED TO CLEAR THE REGION LATE TUESDAY
AFTERNOON WITH 850MB TEMPS EXPECTED TO PLUNGE BACK BELOW -10C FOR
THE ENTIRE CWA. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A BRIEF
ORGANIZED LAKE EFFECT WITH CLIMBING INVERSION HEIGHTS TUESDAY
EVENING BEFORE FALLING ONCE AGAIN OVERNIGHT. AT THIS POINT...SEEMS
ACCUMULATIONS WILL BE LIMITED AND ISOLATED WITH GENERALLY AROUND 1
INCH. AS UPPER TROUGH SLIDES EAST OF THE REGION...INVERSION
HEIGHTS DROP QUICKLY AS DOES THE DRY AIR ADVECTION ACROSS NY
STATE.
A NARROW SURFACE RIDGE IS EXPECTED ACROSS THE REGION DESPITE
ANOTHER SHORT WAVE MOVING ACROSS THE NORTHERN TIER OF NY AND NEW
ENGLAND. WITH LIMITED MOISTURE...WE WILL KEEP SKIES PTCLOUDY AND
NO MENTION OF PRECIP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE PERIOD WILL START OUT WITH A RIDGE MOVING ACROSS THE REGION AT
THE SURFACE WITH THE FLOW ALOFT FLATTENING. THE MODELS ARE IN FAIRLY
GOOD AGREEMENT WITH THE LONGWAVE PATTERN...HOWEVER THERE ARE
DIFFERENCES IN THE TIMING AND TRACK OF THE SOUTHERN STREAM SYSTEM
WHICH ORIGINATES OVER THE SOUTHERN PLAINS AND HEADS OUR WAY LATE IN
THE WEEK. THERE IS A QUESTION OF HOW MUCH INTERACTION THERE WILL BE
WITH THE NORTHERN STREAM. AT THIS TIME...THIS SYSTEM IS EXPECTED TO
PASS TO SOUTH BRINGING THE CHANCES FOR PRECIPITATION TO THE AREA
THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO RUN ABOVE
NORMAL WITH THE LONGWAVE PATTERN KEEPING THE COLDER AIR TO OUR NORTH
THROUGH THE WORK WEEK. INDICATIONS ARE NORTHERN STREAM ENERGY WILL
DIVE INTO THE NORTHERN PLAINS CAUSING A TROUGH TO DIG OVER THE
EASTERN UNITED STATES OVER THE WEEKEND RETURNING MORE SEASONABLE AIR
TO THE REGION.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
CEILINGS HAVE LOWERED TO MVFR AS THE LOWEST LEVELS OF THE ATMOSPHERE
HAVE FINALLY MOISTEN UP. HAVE HAD REPORTS OF LIGHT DRIZZLE AND
TEMPERATURES ARE AT OR JUST BELOW FREEZING SO WE HAVE FREEZING
DRIZZLE. TEMPERATURES WILL RISE TO ABOVE THE FREEZING MARK BEFORE
THE STEADIER AND HEAVIER PRECIPITATION MOVES IN THIS AFTERNOON.
WIDESPREAD IFR CONDITIONS WILL DEVELOP. THE STEADY PRECIPITATION
WILL MOVE OFF TO THE EAST DURING THE EVENING...HOWEVER IFR
CONDITIONS ARE EXPECTED TO LINGER INTO THE EARLY MORNING HOURS. AN
IMPROVEMENT TO MVFR IS EXPECTED BEFORE SUNRISE WITH VFR DEVELOPING
AT KPOU.
OUTLOOK...
MON NIGHT...MVFR/IFR...IMPROVING TO MVFR/VFR. RAIN TAPERING OFF TO
SCATTERED SHOWERS.
TUE-WED...VFR. NO SIG WX.
THU...MAINLY VFR. CHC -RA/-SN BY LATE IN THE AFTERNOON.
THU NIGHT-FRI..VFR/MVFR. CHC -SHSN/-SHRA.
&&
.HYDROLOGY...
A STORM SYSTEM WILL BRING MIXED PRECIPITATION CHANGING TO RAIN
TODAY. A QUICK SHOT OF MODERATE TO HEAVY RAIN IS POSSIBLE THIS
AFTERNOON WITH A COLD FRONT AS QPF VALUES ARE EXPECTED TO BE BETWEEN
ONE QUARTER TO ONE HALF INCH WITH LOCALIZED AMOUNTS AROUND AN INCH
POSSIBLE INTO THE HIGHER TERRAIN OF THE CATSKILLS...SOUTHERN VERMONT
AND BERKSHIRES.
WE MEASURED THE GROUND FROZEN TO A DEPTH OF 14 INCHES HERE AT THE
OFFICE ON SUNDAY. SOME LOCALIZED POOR DRAINAGE...URBAN AND SMALL
STREAM FLOODING MAY BE POSSIBLE LATER MONDAY DUE TO ENHANCED RUNOFF
FROM RAIN AND MELT ON FROZEN GROUND.
SOME SIGNIFICANT RISES ON MAIN STEM RIVERS ARE POSSIBLE MONDAY INTO
TUESDAY...BUT LARGER RIVER FLOODING IS NOT EXPECTED AT THIS TIME.
RISES WOULD BE ENOUGH TO BREAK UP WHAT RIVER ICE IS IN PLACE BUT ICE
IS NOT THICK ENOUGH TO CAUSE SIGNIFICANT ICE JAM PROBLEMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR CTZ001-013.
NY...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NYZ039-040-
047>054-058-061-063-066.
FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NYZ032-033-038-041>043-082>084.
MA...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
VT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
&&
$$
SYNOPSIS...KL/BGM
NEAR TERM...KL/BGM
SHORT TERM...BGM
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...SND/BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
642 AM EST MON JAN 23 2012
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE AND PROVIDE THE
REGION WITH SOME LIGHT ICING CONDITIONS THIS MORNING. TEMPERATURES
WILL CLIMB ABOVE FREEZING THIS AFTERNOON FOR MAINLY RAIN SHOWERS
THAT WILL ACCOMPANY THE FRONTAL BOUNDARY. SOMEWHAT COOLER AIR WILL
FILTER IN FOR TUESDAY WITH SOME LAKE EFFECT SNOW DOWNWIND OF LAKE
ONTARIO. TRANQUIL CONDITIONS FOR THE MID WEEK AS A RIDGE OF HIGH
PRESSURE TRACKS ACROSS THE AREA.
&&
.NEAR TERM /UNTIL NOON TODAY/...
AS OF 6 AM...DRIZZLE IS BEGINNING TO SHOW UP ACROSS THE TRI-STATE
REGION AND MID-HUDSON VALLEY INCLUDING OUR RADAR IN VCP31.
TEMPERATURES VARY BUT THEY DO HOVER AROUND THE FREEZING MARK WHERE
DRIZZLE IS BEING REPORTED. NCEP MODEL SUITE ALONG WITH THE
RUC13/HRRR NOT DOING THAT WELL...HOWEVER...THEY DO SUGGEST THIS
AREA OF DRIZZLE AND SATURATING BOUNDARY LAYER ADVANCES SLOWLY
NORTH THIS MORNING. WET BULB PROFILES ARE STILL BELOW FREEZING SO
WE WILL CONTINUE WITH THE ADVISORY AND REFRESH THE GRIDS AND
HOURLY TEMPS/DEWPTS. PER THE 06Z MOS AND HOURLY LAV/LAMP...MOST
AREAS WILL CLIMB ABOVE FREEZING AROUND THE NOON HOUR.
PREV DISC...
VERY CHALLENGING NEAR TERM FORECAST AS FZDZ HAS NOT
MATERIALIZED AT THIS TIME. PER METARS...THE CIGS REMAIN RATHER
HIGH AND DEWPOINT DEPRESSIONS ARE 5 DEGREES OR GREATER. WE DID
RECEIVE A REPORT OF FLURRIES IN LITCHFIELD COUNTY AND THIS CAN
ALSO BE CONFIRMED WITH SEVERAL METARS ACROSS THE NYC METRO AREA
REPORTING LIGHT SNOW. THIS MAY BE DUE TO THE OCEANIC EFFECT ADDING
ENOUGH NUCLEI TO RESULT IN THOSE OBS OF LIGHT SNOW. THE FORECAST
SOUNDINGS ACROSS OUR REGION STILL SUGGEST THE BOUNDARY LAYER WILL
MOISTEN UP BELOW THE -10C ISOTHERM INCLUDING THE SHEAR PROFILES
FOR SOME DRIZZLE FORMATION. RUC13 FORECAST SOUNDINGS DELAY THE
ONSET OF MOISTURE UNTIL THE 12-15Z TIME FRAME. BY THAT
TIME...TEMPERATURES ARE BEGINNING TO CLIMB TO AT OR ABOVE FREEZING
ALONG AND SOUTH OF I90. THE COLDER AIR IS EXPECTED TO REMAIN IN
PLACE LONGER ACROSS THE DACKS...LAKE GEORGE SARATOGA REGION AND
SOUTHERN VERMONT UNTIL ABOUT THE NOON HOUR. THE ADVISORY LOOKS
GOOD AT THIS TIME WITH NO CHANGES EXPECTED.
&&
.SHORT TERM /NOON TODAY THROUGH WEDNESDAY/...
POTENT SHORT WAVE TRACKING NORTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY INTO THE GREAT LAKES REGION WILL SEND A COLD FRONT EASTWARD
THIS AFTERNOON. A BAND OF BKN SHOWERS IS EXPECTED AND WE WILL
PLACE CATEGORICAL POPS FOR THE ENTIRE REGION. TIMING OF THIS FRONT
APPEARS TO BE AOA 21Z. AS FOR CONVECTIVE POTENTIAL /IE
THUNDER/...THE SHOWALTER INDEX IS EXPECTED TO DROP TOWARD 0C FOR
PORTIONS OF THE REGION WITH THE BEST UPPER SUPPORT FOR THE WESTERN
MOHAWK VALLEY AND DACKS. WHILE WE WILL NOT INCLUDE THUNDER...WOULD
NOT TOTALLY RULE OUT A RUMBLE OF THUNDER.
WITH FROPA...DRY SLOT QUICKLY APPROACHES THIS EARLY EVENING. SOME
LINGERING UPSLOPE SHOWERS ARE EXPECTED BUT THIS TOO SHOULD
DECREASE THROUGH TONIGHT. SEEMS THE INITIAL COLD ADVECTION WILL
REMAIN WEST OF THE HUDSON RIVER VALLEY WITH TEMPERATURES OVERNIGHT
REMAINING ABOVE FREEZING FOR A GOOD PORTION OF THE REGION. THE
EXCEPTION TO THIS WILL BE FOR PORTIONS OF THE DACKS. LAKE ONTARIO
CONTRIBUTION INCREASES A BIT...ALBEIT MARGINALLY...TO WARRANT
CHANCE POPS FOR RAIN/SNOW SHOWERS TRANSITIONING TO SNOW SHOWER
OVERNIGHT.
DUE TO A RELATIVELY MILDER START TO THE DAY TUESDAY...TEMPERATURES
FOR THE REGION SHOULD ONCE AGAIN CLIMB ABOVE THE FREEZING WITH MID
40S EXPECTED FOR THE MID HUDSON RIVER VALLEY AND NW CT. CYCLONIC
FLOW REMAINS OVER LAKE ONTARIO AND THE DACKS WITH A VEERING WIND
PROFILE TO TAKE WHAT BANDS OF LAKE EFFECT ACTIVITY FURTHER SOUTH.
SECONDARY COLD FRONT IS EXPECTED TO CLEAR THE REGION LATE TUESDAY
AFTERNOON WITH 850MB TEMPS EXPECTED TO PLUNGE BACK BELOW -10C FOR
THE ENTIRE CWA. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A BRIEF
ORGANIZED LAKE EFFECT WITH CLIMBING INVERSION HEIGHTS TUESDAY
EVENING BEFORE FALLING ONCE AGAIN OVERNIGHT. AT THIS POINT...SEEMS
ACCUMULATIONS WILL BE LIMITED AND ISOLATED WITH GENERALLY AROUND 1
INCH. AS UPPER TROUGH SLIDES EAST OF THE REGION...INVERSION
HEIGHTS DROP QUICKLY AS DOES THE DRY AIR ADVECTION ACROSS NY
STATE.
A NARROW SURFACE RIDGE IS EXPECTED ACROSS THE REGION DESPITE
ANOTHER SHORT WAVE MOVING ACROSS THE NORTHERN TIER OF NY AND NEW
ENGLAND. WITH LIMITED MOISTURE...WE WILL KEEP SKIES PTCLOUDY AND
NO MENTION OF PRECIP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE PERIOD WILL START OUT WITH A RIDGE MOVING ACROSS THE REGION AT
THE SURFACE WITH THE FLOW ALOFT FLATTENING. THE MODELS ARE IN FAIRLY
GOOD AGREEMENT WITH THE LONGWAVE PATTERN...HOWEVER THERE ARE
DIFFERENCES IN THE TIMING AND TRACK OF THE SOUTHERN STREAM SYSTEM
WHICH ORIGINATES OVER THE SOUTHERN PLAINS AND HEADS OUR WAY LATE IN
THE WEEK. THERE IS A QUESTION OF HOW MUCH INTERACTION THERE WILL BE
WITH THE NORTHERN STREAM. AT THIS TIME...THIS SYSTEM IS EXPECTED TO
PASS TO SOUTH BRINGING THE CHANCES FOR PRECIPITATION TO THE AREA
THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO RUN ABOVE
NORMAL WITH THE LONGWAVE PATTERN KEEPING THE COLDER AIR TO OUR NORTH
THROUGH THE WORK WEEK. INDICATIONS ARE NORTHERN STREAM ENERGY WILL
DIVE INTO THE NORTHERN PLAINS CAUSING A TROUGH TO DIG OVER THE
EASTERN UNITED STATES OVER THE WEEKEND RETURNING MORE SEASONABLE AIR
TO THE REGION.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
CEILINGS HAVE LOWERED TO MVFR AS THE LOWEST LEVELS OF THE ATMOSPHERE
HAVE FINALLY MOISTEN UP. HAVE HAD REPORTS OF LIGHT DRIZZLE AND
TEMPERATURES ARE AT OR JUST BELOW FREEZING SO WE HAVE FREEZING
DRIZZLE. TEMPERATURES WILL RISE TO ABOVE THE FREEZING MARK BEFORE
THE STEADIER AND HEAVIER PRECIPITATION MOVES IN THIS AFTERNOON.
WIDESPREAD IFR CONDITIONS WILL DEVELOP. THE STEADY PRECIPITATION
WILL MOVE OFF TO THE EAST DURING THE EVENING...HOWEVER IFR
CONDITIONS ARE EXPECTED TO LINGER INTO THE EARLY MORNING HOURS. AN
IMPROVEMENT TO MVFR IS EXPECTED BEFORE SUNRISE WITH VFR DEVELOPING
AT KPOU.
OUTLOOK...
MON NIGHT...MVFR/IFR...IMPROVING TO MVFR/VFR. RAIN TAPERING OFF TO
SCATTERED SHOWERS.
TUE-WED...VFR. NO SIG WX.
THU...MAINLY VFR. CHC -RA/-SN BY LATE IN THE AFTERNOON.
THU NIGHT-FRI..VFR/MVFR. CHC -SHSN/-SHRA.
&&
.HYDROLOGY...
A STORM SYSTEM WILL BRING MIXED PRECIPITATION CHANGING TO RAIN
TODAY. A QUICK SHOT OF MODERATE TO HEAVY RAIN IS POSSIBLE THIS
AFTERNOON WITH A COLD FRONT AS QPF VALUES ARE EXPECTED TO BE BETWEEN
ONE QUARTER TO ONE HALF INCH WITH LOCALIZED AMOUNTS AROUND AN INCH
POSSIBLE INTO THE HIGHER TERRAIN OF THE CATSKILLS...SOUTHERN VERMONT
AND BERKSHIRES.
WE MEASURED THE GROUND FROZEN TO A DEPTH OF 14 INCHES HERE AT THE
OFFICE ON SUNDAY. SOME LOCALIZED POOR DRAINAGE...URBAN AND SMALL
STREAM FLOODING MAY BE POSSIBLE LATER MONDAY DUE TO ENHANCED RUNOFF
FROM RAIN AND MELT ON FROZEN GROUND.
SOME SIGNIFICANT RISES ON MAIN STEM RIVERS ARE POSSIBLE MONDAY INTO
TUESDAY...BUT LARGER RIVER FLOODING IS NOT EXPECTED AT THIS TIME.
RISES WOULD BE ENOUGH TO BREAK UP WHAT RIVER ICE IS IN PLACE BUT ICE
IS NOT THICK ENOUGH TO CAUSE SIGNIFICANT ICE JAM PROBLEMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR CTZ001-013.
NY...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NYZ039-040-
047>054-058>061-063>066.
FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NYZ032-033-038-041>043-082>084.
MA...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
VT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...SND/BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
619 AM EST MON JAN 23 2012
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE AND PROVIDE THE
REGION WITH SOME LIGHT ICING CONDITIONS THIS MORNING. TEMPERATURES
WILL CLIMB ABOVE FREEZING THIS AFTERNOON FOR MAINLY RAIN SHOWERS
THAT WILL ACCOMPANY THE FRONTAL BOUNDARY. SOMEWHAT COOLER AIR WILL
FILTER IN FOR TUESDAY WITH SOME LAKE EFFECT SNOW DOWNWIND OF LAKE
ONTARIO. TRANQUIL CONDITIONS FOR THE MID WEEK AS A RIDGE OF HIGH
PRESSURE TRACKS ACROSS THE AREA.
&&
.NEAR TERM /UNTIL NOON TODAY/...
AS OF 6 AM...DRIZZLE IS BEGINNING TO SHOW UP ACROSS THE TRI-STATE
REGION AND MID-HUDSON VALLEY INCLUDING OUR RADAR IN VCP31.
TEMPERATURES VARY BUT THEY DO HOVER AROUND THE FREEZING MARK WHERE
DRIZZLE IS BEING REPORTED. NCEP MODEL SUITE ALONG WITH THE
RUC13/HRRR NOT DOING THAT WELL...HOWEVER...THEY DO SUGGEST THIS
AREA OF DRIZZLE AND SATURATING BOUNDARY LAYER ADVANCES SLOWLY
NORTH THIS MORNING. WET BULB PROFILES ARE STILL BELOW FREEZING SO
WE WILL CONTINUE WITH THE ADVISORY AND REFRESH THE GRIDS AND
HOURLY TEMPS/DEWPTS. PER THE 06Z MOS AND HOURLY LAV/LAMP...MOST
AREAS WILL CLIMB ABOVE FREEZING AROUND THE NOON HOUR.
PREV DISC...
VERY CHALLENGING NEAR TERM FORECAST AS FZDZ HAS NOT
MATERIALIZED AT THIS TIME. PER METARS...THE CIGS REMAIN RATHER
HIGH AND DEWPOINT DEPRESSIONS ARE 5 DEGREES OR GREATER. WE DID
RECEIVE A REPORT OF FLURRIES IN LITCHFIELD COUNTY AND THIS CAN
ALSO BE CONFIRMED WITH SEVERAL METARS ACROSS THE NYC METRO AREA
REPORTING LIGHT SNOW. THIS MAY BE DUE TO THE OCEANIC EFFECT ADDING
ENOUGH NUCLEI TO RESULT IN THOSE OBS OF LIGHT SNOW. THE FORECAST
SOUNDINGS ACROSS OUR REGION STILL SUGGEST THE BOUNDARY LAYER WILL
MOISTEN UP BELOW THE -10C ISOTHERM INCLUDING THE SHEAR PROFILES
FOR SOME DRIZZLE FORMATION. RUC13 FORECAST SOUNDINGS DELAY THE
ONSET OF MOISTURE UNTIL THE 12-15Z TIME FRAME. BY THAT
TIME...TEMPERATURES ARE BEGINNING TO CLIMB TO AT OR ABOVE FREEZING
ALONG AND SOUTH OF I90. THE COLDER AIR IS EXPECTED TO REMAIN IN
PLACE LONGER ACROSS THE DACKS...LAKE GEORGE SARATOGA REGION AND
SOUTHERN VERMONT UNTIL ABOUT THE NOON HOUR. THE ADVISORY LOOKS
GOOD AT THIS TIME WITH NO CHANGES EXPECTED.
&&
.SHORT TERM /NOON TODAY THROUGH WEDNESDAY/...
POTENT SHORT WAVE TRACKING NORTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY INTO THE GREAT LAKES REGION WILL SEND A COLD FRONT EASTWARD
THIS AFTERNOON. A BAND OF BKN SHOWERS IS EXPECTED AND WE WILL
PLACE CATEGORICAL POPS FOR THE ENTIRE REGION. TIMING OF THIS FRONT
APPEARS TO BE AOA 21Z. AS FOR CONVECTIVE POTENTIAL /IE
THUNDER/...THE SHOWALTER INDEX IS EXPECTED TO DROP TOWARD 0C FOR
PORTIONS OF THE REGION WITH THE BEST UPPER SUPPORT FOR THE WESTERN
MOHAWK VALLEY AND DACKS. WHILE WE WILL NOT INCLUDE THUNDER...WOULD
NOT TOTALLY RULE OUT A RUMBLE OF THUNDER.
WITH FROPA...DRY SLOT QUICKLY APPROACHES THIS EARLY EVENING. SOME
LINGERING UPSLOPE SHOWERS ARE EXPECTED BUT THIS TOO SHOULD
DECREASE THROUGH TONIGHT. SEEMS THE INITIAL COLD ADVECTION WILL
REMAIN WEST OF THE HUDSON RIVER VALLEY WITH TEMPERATURES OVERNIGHT
REMAINING ABOVE FREEZING FOR A GOOD PORTION OF THE REGION. THE
EXCEPTION TO THIS WILL BE FOR PORTIONS OF THE DACKS. LAKE ONTARIO
CONTRIBUTION INCREASES A BIT...ALBEIT MARGINALLY...TO WARRANT
CHANCE POPS FOR RAIN/SNOW SHOWERS TRANSITIONING TO SNOW SHOWER
OVERNIGHT.
DUE TO A RELATIVELY MILDER START TO THE DAY TUESDAY...TEMPERATURES
FOR THE REGION SHOULD ONCE AGAIN CLIMB ABOVE THE FREEZING WITH MID
40S EXPECTED FOR THE MID HUDSON RIVER VALLEY AND NW CT. CYCLONIC
FLOW REMAINS OVER LAKE ONTARIO AND THE DACKS WITH A VEERING WIND
PROFILE TO TAKE WHAT BANDS OF LAKE EFFECT ACTIVITY FURTHER SOUTH.
SECONDARY COLD FRONT IS EXPECTED TO CLEAR THE REGION LATE TUESDAY
AFTERNOON WITH 850MB TEMPS EXPECTED TO PLUNGE BACK BELOW -10C FOR
THE ENTIRE CWA. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A BRIEF
ORGANIZED LAKE EFFECT WITH CLIMBING INVERSION HEIGHTS TUESDAY
EVENING BEFORE FALLING ONCE AGAIN OVERNIGHT. AT THIS POINT...SEEMS
ACCUMULATIONS WILL BE LIMITED AND ISOLATED WITH GENERALLY AROUND 1
INCH. AS UPPER TROUGH SLIDES EAST OF THE REGION...INVERSION
HEIGHTS DROP QUICKLY AS DOES THE DRY AIR ADVECTION ACROSS NY
STATE.
A NARROW SURFACE RIDGE IS EXPECTED ACROSS THE REGION DESPITE
ANOTHER SHORT WAVE MOVING ACROSS THE NORTHERN TIER OF NY AND NEW
ENGLAND. WITH LIMITED MOISTURE...WE WILL KEEP SKIES PTCLOUDY AND
NO MENTION OF PRECIP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE PERIOD WILL START OUT WITH A RIDGE MOVING ACROSS THE REGION AT
THE SURFACE WITH THE FLOW ALOFT FLATTENING. THE MODELS ARE IN FAIRLY
GOOD AGREEMENT WITH THE LONGWAVE PATTERN...HOWEVER THERE ARE
DIFFERENCES IN THE TIMING AND TRACK OF THE SOUTHERN STREAM SYSTEM
WHICH ORIGINATES OVER THE SOUTHERN PLAINS AND HEADS OUR WAY LATE IN
THE WEEK. THERE IS A QUESTION OF HOW MUCH INTERACTION THERE WILL BE
WITH THE NORTHERN STREAM. AT THIS TIME...THIS SYSTEM IS EXPECTED TO
PASS TO SOUTH BRINGING THE CHANCES FOR PRECIPITATION TO THE AREA
THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO RUN ABOVE
NORMAL WITH THE LONGWAVE PATTERN KEEPING THE COLDER AIR TO OUR NORTH
THROUGH THE WORK WEEK. INDICATIONS ARE NORTHERN STREAM ENERGY WILL
DIVE INTO THE NORTHERN PLAINS CAUSING A TROUGH TO DIG OVER THE
EASTERN UNITED STATES OVER THE WEEKEND RETURNING MORE SEASONABLE AIR
TO THE REGION.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL LOWER TO MVFR EARLY THIS MORNING AS THE LOW
LEVELS OF THE ATMOSPHERE MOISTEN UP AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. THE CHANCES FOR FREEZING DRIZZLE WILL THEN
INCREASE. TEMPERATURES ARE EXPECTED TO RISE TO ABOVE THE FREEZING
MARK BEFORE THE STEADIER AND HEAVIER PRECIPITATION MOVES IN THIS
AFTERNOON WITH CONDITIONS LOWERING TO IFR. THE STEADY PRECIPITATION
WILL MOVE OFF TO THE EAST DURING THE EVENING HOWEVER IFR CONDITIONS
ARE EXPECTED TO LINGER.
OUTLOOK...
MON NIGHT...MVFR/IFR...IMPROVING TO MVFR/VFR. RAIN TAPERING OFF TO
SCATTERED SHOWERS.
TUE-WED...VFR. NO SIG WX.
THU...MAINLY VFR. CHC -RA/-SN BY LATE IN THE AFTERNOON.
THU NIGHT-FRI..VFR/MVFR. CHC -SHSN/-SHRA.
&&
.HYDROLOGY...
A STORM SYSTEM WILL BRING MIXED PRECIPITATION CHANGING TO RAIN
TODAY. A QUICK SHOT OF MODERATE TO HEAVY RAIN IS POSSIBLE THIS
AFTERNOON WITH A COLD FRONT AS QPF VALUES ARE EXPECTED TO BE BETWEEN
ONE QUARTER TO ONE HALF INCH WITH LOCALIZED AMOUNTS AROUND AN INCH
POSSIBLE INTO THE HIGHER TERRAIN OF THE CATSKILLS...SOUTHERN VERMONT
AND BERKSHIRES.
WE MEASURED THE GROUND FROZEN TO A DEPTH OF 14 INCHES HERE AT THE
OFFICE ON SUNDAY. SOME LOCALIZED POOR DRAINAGE...URBAN AND SMALL
STREAM FLOODING MAY BE POSSIBLE LATER MONDAY DUE TO ENHANCED RUNOFF
FROM RAIN AND MELT ON FROZEN GROUND.
SOME SIGNIFICANT RISES ON MAIN STEM RIVERS ARE POSSIBLE MONDAY INTO
TUESDAY...BUT LARGER RIVER FLOODING IS NOT EXPECTED AT THIS TIME.
RISES WOULD BE ENOUGH TO BREAK UP WHAT RIVER ICE IS IN PLACE BUT ICE
IS NOT THICK ENOUGH TO CAUSE SIGNIFICANT ICE JAM PROBLEMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR CTZ001-013.
NY...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NYZ039-040-
047>054-058>061-063>066.
FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NYZ032-033-038-041>043-082>084.
MA...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
VT...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...SND/BGM
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
928 AM EST MON JAN 23 2012
.SYNOPSIS...
THE SURFACE WEDGE WILL SLOWLY SHIFT NORTH/NORTHWEST DURING TODAY.
A WEAK FRONT WILL SLOWLY MOVE ACROSS THE REGION TONIGHT AND
TUESDAY MORNING. FAIR WEATHER EXPECTED TUESDAY INTO WEDNESDAY...THEN
RETURNING MOISTURE AND THE APPROACH OF ANOTHER WEATHER SYSTEM WILL
PROVIDE A CHANCE OF PRECIPITATION LATE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DENSE FOG DEVELOPING ACROSS THE CENTRAL AND SOUTH MIDLANDS/CSRA.
WILL ISSUE DENSE FOG ADVISORY UNTIL 300 PM.
LATEST RUC MODEL SUGGEST WEDGE WILL NOT BREAK DOWN THIS
AFTERNOON...MODELS USUALLY BREAK WEDGE TOO QUICKLY...SO WILL LOWER
MAXIMUM TEMPERATURES ABOUT 10 DEGREES.
THE MORNING DRIZZLE WILL GIVE WAY TO A CHANCE OF SHOWERS AS THE
WEDGE BREAKS AHEAD OF AN APPROACHING COLD FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE COLD FRONT WILL BE SLOW TO PASS THROUGH THE REGION TONIGHT.
HOWEVER IT APPEARS MOISTURE WILL BE LIMITED...AND MUCH OF THE
UPPER ENERGY WILL HAVE PASSED NORTH OF THE REGION. HAVE ELECTED TO
GO WITH A DRY FORECAST TONIGHT. DID PUT MENTION OF FOG IN FOR NOW.
THE FRONT WILL STALL OUT SOUTH OF THE FORECAST AREA TUESDAY AND
TUESDAY NIGHT. DRY WEATHER EXPECTED THROUGH THAT PERIOD. EVEN
THOUGH THE FRONT WILL BE SOUTH...MORE SUNSHINE ON TUESDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE 60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
LITTLE TO NO CHANGES WERE MADE IN THE LONG TERM. PREVIOUS
DISCUSSION FOLLOWS. GFS/ECMWF CLOSE OFF UPPER LOW AND MOVE IT
SLOWLY EAST ACROSS TEXAS WED/THU. MEANWHILE SURFACE HIGH CENTER
RIDES BY TO OUR NORTH...AND WEAK FRONT LIFTS SLOWLY BACK NORTH
ACROSS OUR REGION. THIS COULD PROVIDE SLIGHT CHANCE POPS...WITH
WEAK ISENTROPIC LIFT BY THURSDAY. BOTH GFS/ECMWF OPEN THE UPPER
LOW AND SHIFT IT EAST ACROSS OUR REGION...BUT DIFFERENCE IN
SOLUTIONS REGARDS TIMING. ECMWF RUN OPENS IT UP EARLIER THAN GFS.
WILL INDICATE HIGH END CHANCE POPS THU NT THRU FRI NT. HIGH
PRESSURE TO BUILD IN BEHIND FRONT LATE IN THE FORECAST PERIOD.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
COLD AIR DAMMING PERSISTS ACROSS THE REGION WITH IFR CIGS/VSBYS
EARLY THIS MORNING UNTIL AROUND 14Z-15Z THIS MORNING AS MOISTURE
FLUX AND INCREASE ISENTROPIC LIFT OVER REGION PRODUCING EITHER
DRIZZLE OR PATCHY LIGHT RAIN ALONG WITH AREAS OF FOG.
WARM FRONT IS EXPECTED TO APPROACH AND BUT REMAIN SOUTH OF THE
AREA THROUGH MOST OF THE AFTERNOON. 17Z- 18Z SCATTERED SHOWERS.
CIGS IFR AND MAY BE MVFR BY LATER THIS AFTERNOON CONTINUING INTO
THE EVENING HOURS. ALSO...WITH INCREASING LOW LEVEL WINDS
SOUTHWEST AROUND 30 KNOTS AT 1-2 KFT WITH WARM FRONT LATER THIS
AFTERNOON MAY LEAD TO LOW LEVEL WIND SHEAR MONDAY AFTERNOON AS THE
WEDGE BEGINS TO BREAK DOWN. ISOLD STORMS MAY BE POSSIBLE DURING
THE AFTERNOON AS WELL BUT WILL JUST USE VCSH IN THE TAFS FOR NOW
GIVEN CURRENT UNCERTAINTIES. CIGS RISE TO AROUND 4 KFT BY AROUND
01Z TUESDAY AS WARM AIR ADVECTION AHEAD OF THE COLD FRONT
INCREASES. AFTER FROPA THIS EVENING...WITH SW FLOW ALOFT...MVFR-
IFR CIGS/VSBYS POSSIBLE UNTIL THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...CEILINGS/VISIBILITIES BECOMING VFR
TUESDAY MORNING. WIDESPREAD IFR CONDITION MAY OCCUR WEDNESDAY NIGHT
THROUGH THURSDAY ASSOCIATED WITH ANOTHER FRONTAL SYSTEM.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR SCZ018-
020-025>028-030-031-035>038-041.
GA...DENSE FOG ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR GAZ040-
063>065-077.
&&
$$
SYNOPSIS...77
NEAR TERM...77
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
741 AM EST MON JAN 23 2012
.SYNOPSIS...
THE SURFACE WEDGE WILL SLOWLY SHIFT NORTH/NORTHWEST DURING TODAY.
A WEAK FRONT WILL SLOWLY MOVE ACROSS THE REGION TONIGHT AND
TUESDAY MORNING. FAIR WEATHER EXPECTED TUESDAY INTO WEDNESDAY...THEN
RETURNING MOISTURE AND THE APPROACH OF ANOTHER WEATHER SYSTEM WILL
PROVIDE A CHANCE OF PRECIPITATION LATE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST RUC MODEL SUGGEST WEDGE WILL NOT BREAK DOWN THIS
AFTERNOON...MODELS USUALLY BREAK WEDGE TOO QUICKLY...SO WILL
LOWER MAXIMUM TEMPERATURES ABOUT 10 DEGREES.
THE MORNING DRIZZLE WILL GIVE WAY TO A CHANCE OF SHOWERS AS THE
WEDGE BREAKS AHEAD OF AN APPROACHING COLD FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE COLD FRONT WILL BE SLOW TO PASS THROUGH THE REGION TONIGHT.
HOWEVER IT APPEARS MOISTURE WILL BE LIMITED...AND MUCH OF THE
UPPER ENERGY WILL HAVE PASSED NORTH OF THE REGION. HAVE ELECTED TO
GO WITH A DRY FORECAST TONIGHT. DID PUT MENTION OF FOG IN FOR NOW.
THE FRONT WILL STALL OUT SOUTH OF THE FORECAST AREA TUESDAY AND
TUESDAY NIGHT. DRY WEATHER EXPECTED THROUGH THAT PERIOD. EVEN
THOUGH THE FRONT WILL BE SOUTH...MORE SUNSHINE ON TUESDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE 60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
LITTLE TO NO CHANGES WERE MADE IN THE LONG TERM. PREVIOUS
DISCUSSION FOLLOWS. GFS/ECMWF CLOSE OFF UPPER LOW AND MOVE IT
SLOWLY EAST ACROSS TEXAS WED/THU. MEANWHILE SURFACE HIGH CENTER
RIDES BY TO OUR NORTH...AND WEAK FRONT LIFTS SLOWLY BACK NORTH
ACROSS OUR REGION. THIS COULD PROVIDE SLIGHT CHANCE POPS...WITH
WEAK ISENTROPIC LIFT BY THURSDAY. BOTH GFS/ECMWF OPEN THE UPPER
LOW AND SHIFT IT EAST ACROSS OUR REGION...BUT DIFFERENCE IN
SOLUTIONS REGARDS TIMING. ECMWF RUN OPENS IT UP EARLIER THAN GFS.
WILL INDICATE HIGH END CHANCE POPS THU NT THRU FRI NT. HIGH
PRESSURE TO BUILD IN BEHIND FRONT LATE IN THE FORECAST PERIOD.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
COLD AIR DAMMING PERSISTS ACROSS THE REGION WITH IFR CIGS/VSBYS
EARLY THIS MORNING UNTIL AROUND 14Z-15Z THIS MORNING AS MOISTURE
FLUX AND INCREASE ISENTROPIC LIFT OVER REGION PRODUCING EITHER
DRIZZLE OR PATCHY LIGHT RAIN ALONG WITH AREAS OF FOG.
WARM FRONT IS EXPECTED TO APPROACH AND BUT REMAIN SOUTH OF THE
AREA THROUGH MOST OF THE AFTERNOON. 17Z- 18Z SCATTERED SHOWERS.
CIGS IFR AND MAY BE MVFR BY LATER THIS AFTERNOON CONTINUING INTO
THE EVENING HOURS. ALSO...WITH INCREASING LOW LEVEL WINDS
SOUTHWEST AROUND 30 KNOTS AT 1-2 KFT WITH WARM FRONT LATER THIS
AFTERNOON MAY LEAD TO LOW LEVEL WIND SHEAR MONDAY AFTERNOON AS THE
WEDGE BEGINS TO BREAK DOWN. ISOLD STORMS MAY BE POSSIBLE DURING
THE AFTERNOON AS WELL BUT WILL JUST USE VCSH IN THE TAFS FOR NOW
GIVEN CURRENT UNCERTAINTIES. CIGS RISE TO AROUND 4 KFT BY AROUND
01Z TUESDAY AS WARM AIR ADVECTION AHEAD OF THE COLD FRONT
INCREASES. AFTER FROPA THIS EVENING...WITH SW FLOW ALOFT...MVFR-
IFR CIGS/VSBYS POSSIBLE UNTIL THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...CEILINGS/VISIBILITIES BECOMING VFR
TUESDAY MORNING. WIDESPREAD IFR CONDITION MAY OCCUR WEDNESDAY NIGHT
THROUGH THURSDAY ASSOCIATED WITH ANOTHER FRONTAL SYSTEM.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...77
NEAR TERM...77
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
614 AM CST MON JAN 23 2012
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
THE MAIN FORECAST CHALLENGE TODAY...IS TRYING TO DETERMINE HOW MUCH
SNOWFALL IS EXPECTED THROUGH THIS AFTERNOON. A CLOSED LOW
PRESSURE AREA OVER ERN IOWA WILL PIVOT NORTHEAST OVER THE WRN
GREAT LAKES AND ONTARIO CANADA TODAY. A COUPLE OF SEEDER- FEEDER
BANDS OF ENHANCED CLOUDS WERE OCCURRING OVER THE FORECAST AREA AS
PV ANOMALY LIFTS NORTHEASTWARD. EXPECT SNOW TO CONTINUE TO
INTENSIFY OVER WESTERN WISCONSIN AND EAST CENTRAL MN THIS
MORNING...BEFORE DIMINISHING THIS AFTERNOON. EXPECT A FEW MORE
TENTHS OF AN INCH OVER WESTERN MINNESOTA THIS MORNING WITH TOTAL
NEW SNOW AMOUNTS FROM ONE TO THREE INCHES FROM THE TWIN CITIES
EASTWARD. EVEN THOUGH ONE TO TWO INCHES OF SNOW IS ANTICIPATED BY
THE END OF THE MORNING COMMUTE...AFTER A LONG DURATION OF FREEZING
DRIZZLE...UNTREATED ROADS AND EXIT/ENTRANCE RAMPS WILL BE VERY
SLICK. WILL CONTINUE THE WINTER WEATHER ADVISORY THROUGH NOON MOST
AREAS...EXCEPT FOR A SMALL AREA OVER WEST CENTRAL WISCONSIN INTO
THE AFTERNOON TODAY. CLOUDS WILL GRADUALLY CLEAR OVER THE AREA
TONIGHT AS DRIER AIR BEGINS TO FILTER BEHIND THE EXITING LOW
PRESSURE SYSTEM.
UPPER RIDGE BUILDS OVER THE UPPER MIDWEST TONIGHT AND TUESDAY. BY
MID WEEK...THE UPPER AIRFLOW BECOMES MORE ZONAL ACROSS THE NORTHERN
TIER OF THE CONUS. ALTHOUGH...THERE COULD BE A FEW WEAK UPPER
LEVEL DISTURBANCE PASSING OVER THE FORECAST AREA. NO SIGNIFICANT
PRECIPITATION OR WEATHER IS EXPECTED OVER THE NEXT SEVERAL DAYS.
IT WILL TURN COLDER OVER THE WEEKEND AS AN UPPER LEVEL TROUGH CARVES
OUT OVER THE UPPER GREAT LAKES AND MIDWEST. THIS COLD AIRMASS WILL
BE SHORT LIVE AS IT SLIDES OVER TO THE EASTERN SEABOARD NEXT
WEEK.
&&
.AVIATION.../12Z TAF ISSUANCE/
FLIGHT CONDITIONS REMAIN RATHER UGLY THIS MORNING...THOUGH ALL
AREAS HAVE FINALLY CROSSED THE THRESHOLD FROM FZDZ TO SN. UPPER
LOW NOW OVER THE SE TIP OF MN AND IS HEADING FOR NRN WI. OUT
AHEAD OF THIS FEATURE...HAVE SEEN A STRONGER BAND OF SNOW DEVELOP
FROM SE MN INTO WRN WI. BACK WEST EXISTING DEFORMATION BAND THAT
HAS SLOWLY TRUDGED EAST OVERNIGHT NOW INTO TWIN CITIES METRO AND
MOVING THROUGH STC. FOR THE MOST PART CIGS ARE IFR...THOUGH THERE
ARE A COUPLE OF VFR POCKETS AROUND STC/RWF/RNH THAT WILL LEAD TO
SOME VARIABILITY IN CIGS THROUGH THE MORNING AT THESE LOCATIONS.
THESE HIGHER CIGS MAY ALSO GIVE MSP A BRIEF BREAK FROM SUB 017
CIGS THIS MORNING BEFORE THINGS FILL BACK IN. HRRR REFLECTIVITY
AND SREF PROBS FOR VIS LESS THAN 3SM BOTH HANDLING CURRENT SNOW
WELL...SO FOLLOWED TIMING FROM THOSE SOURCES TO MOVE SNOW EAST
ACROSS THE TERMINALS INTO THE AFTERNOON. THOUGH SNOW CURRENTLY
COMES TO AN END AROUND THE SODAK BORDER...EXTENSIVE CLOUD COVER
EXISTS ALL THE WAY OUT TO THE CENTRAL DAKOTAS. 925-850 RH FROM THE
GFS WAS HITTING THE CLOUD LOCATION WELL THIS MORNING...SO USED IT
TO TIME CLEARING THROUGH MN TERMINALS AT THE END OF THE TAFS. ONLY
CHANGE MADE TO GOING WIND FORECAST WAS TO BACK WINDS A BIT FASTER
THIS MORNING...STILL LOOKS GOOD FOR GUSTS OVER 20 KTS BY LATE
MORNING.
KMSP...CAN FINALLY SAY FZDZ IS DONE WITH CONFIDENCE...WITH ANY
PRECIP FROM NOW ON TO FALL AS SN. OBS TO THE WEST WITH BAND COMING
IN HAVE SHOWN THE LOW END OF THE OBSERVED VSBY AT 1SM...SO BROUGHT
TEMPO GROUP ONLY DOWN TO THERE. EXPECT SUB 1SM VSBYS TO REMAIN
EAST OF THE TERMINAL...CLOSER TO THE TRACK OF THE UPPER LOW. FOR
ENDING THE SNOW...EXPECT IFR CONDITION TO LAST THROUGH ABOUT
16Z...BUT MVFR SNOWS COULD LINGER OUT TO AS LATE AS 21Z. AREA OF
MIXED IFR TO VFR CIGS HAS BEEN SLOWLY DRIFTING SE TOWARD THE TWIN
CITIES OVERNIGHT...SO DO EXPECT SOME VARIABILITY WITH CIG HEIGHTS
IN THE SNOW...THOUGH CIGS BELOW 017 SHOULD DOMINATE. TREND THIS
WINTER FROM MODELS AND TAFS HAS BEEN TO BE TO AGGRESSIVE WITH
CLEARING CIGS OUT BEHIND SYSTEMS...SO KEPT RESTRICTED CIGS IN A
BIT LONGER THAN GUIDANCE WOULD SUGGEST.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR ANOKA-BENTON-
BLUE EARTH-BROWN-CARVER-CHISAGO-DAKOTA-FARIBAULT-FREEBORN-
GOODHUE-HENNEPIN-ISANTI-KANABEC-KANDIYOHI-LE SUEUR-MARTIN-
MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-RAMSEY-REDWOOD-
RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-WASECA-
WASHINGTON-WATONWAN-WRIGHT.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR BARRON-DUNN-
PEPIN-PIERCE-POLK-ST. CROIX.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR CHIPPEWA-
EAU CLAIRE-RUSK.
&&
$$
JVM/MPG
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1029 AM EST MON JAN 23 2012
.SYNOPSIS...
STRONG COLD FRONT WHIPS THROUGH THIS AFTERNOON AND EARLY EVENING.
HIGH PRESSURE IN CONTROL TUESDAY AFTERNOON INTO WEDNESDAY. ANOTHER
SYSTEM PROVIDES RAIN WEDNESDAY NIGHT INTO THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
MUCH OF THE SHOWER ACTIVITY HAS DECREASED FROM WEST TO EAST.
COLD FRONT STILL REMAINS WELL TO THE WEST ACROSS INDIANA. BOTH
RADAR AND HRRR MODEL SEEM TO BE INDICATING ANOTHER LINE OF
CONVECTION DEVELOPING OUT AHEAD OF THIS FRONT AS IT PUSHES EAST
INTO THE AREA. SPC HAS SOUTHEAST OHIO IN A SEE TEXT. STILL SOME
UNCERTAINTY AS TO WHETHER THUNDERSTORMS WILL BE ABLE TO
DEVELOP...OR JUST CONVECTIVE SHOWERS...DUE TO WARM AIR ALOFT. FOR
NOW...ADDED ISOLD THUNDER...MAINLY TO SOUTHEAST OHIO ZONES FOR
THIS AFTERNOON AS THE FRONT PUSHES TOWARDS THE REGION. IF ANY
DEEPER CONVECTION IS ABLE TO FORM...STRONGER WINDS ALOFT MAY BE
ABLE TO MIX DOWN TOWARDS THE SURFACE. WILL LET THE WIND ADVISORY
RIDE FOR NOW...AND WILL PROBABLY JUST LET EVENING SHIFT DECIDE
WHETHER TO CANCEL IT EARLY. OTHERWISE...MADE NO MAJOR CHANGES TO
THE FORECAST.
PREVIOUS DISCUSSION...
ALL EYES ARE ON THE LONG LINE OF CONVECTION NOW MOVING ACROSS THE
TENNESSEE AND LOWER OHIO VALLEYS. THIS LINE IS IN ADVANCE OF A COLD
FRONT...WHICH WILL CROSS A BIT LATER THAN THOUGHT PREVIOUSLY...
SOMETHING LIKE THE 20Z TO 03Z RANGE. BEFORE THEN...HAVE SOLID 100
POPS WITH THE MAIN PRECIP LINE...WHICH MOVES THROUGH BETWEEN 10Z AND
15Z. NUMBER OF LIGHTNING STRIKES IS INCHING DOWNWARD...STILL PLENTY
ENOUGH FOR MAINTAINING THUNDER MENTION.
MAIN CONCERN TODAY WILL BE WIND GUSTS. H850 JET OF 60-70
KNOTS WILL REACH THE TRI-STATE AREA BY 12Z...BEFORE WEAKENING AS THE
SURFACE/UPPER LOWS ROTATE NORTH INTO THE GREAT LAKES. STILL SEEING
A FAIRLY STOUT LOW LEVEL INVERSION WHICH WILL KEEP THE STRONGEST OF
THE WINDS ALOFT...KEEPING THE RISK OF SEVERE CONVECTIVE GUSTS IN
CHECK. HOWEVER...LINE OF SHRA/TSRA MAY BE ENOUGH TO DRAG DOWN 30-40
KNOT GUSTS ALONG AND IMMEDIATELY BEHIND THE LINE...AND PLAYED IT
THIS WAY IN THE GRIDS. ONCE INVERSION MIXES OUT LATER
TODAY...SHOULD CONTINUE TO SEE 20-30 KNOT GUSTS. GOING TO CONTINUE
WITH WIND ADVISORY...ALTHOUGH COULD SEE IT BEING CANCELLED BEFORE
EXPIRATION AT 02Z.
DID GO AHEAD AND CANCEL THE FREEZING RAIN ADVISORY FOR THE EASTERN
SLOPES EARLY. WITH TEMPERATURES STRUGGLING TO STAY BELOW FREEZING
AND LACK OF PRECIPITATION...ICE ACCRETION THREAT IS LOOKING MINOR.
STILL COULD SEE A FEW POCKETS AROUND SUNRISE THOUGH.
BEHIND THE MAIN CONVECTIVE LINE...SCATTERED SHOWERS MAY
LINGER...ESPECIALLY ACROSS THE NORTH...AS MAIN H500 TROUGH AXIS/VORT
MAX SKIRTS THE AREA. LINGERING MOISTURE PLUS PEDESTRIAN COLD
ADVECTION MAY BE ENOUGH TO CONTINUE SHRA INTO THE EVENING BEFORE
FROPA. LIMITED POPS TO CHANCE WITH THIS ACTIVITY.
HIGH PRESSURE MOVES FROM THE ARKLATEX INTO THE TENNESSEE VALLEY
TONIGHT...WITH SOUTHWEST FLOW PUSHING DRIER AIR INTO THE REGION.
CLOUDS WILL LINGER ACROSS THE NORTH WHILE SKIES CLEAR ELSEWHERE
ESPECIALLY SOUTH/WEST OF I-64. PRECIPITATION MAY END AS SNOWFLAKES
ON THE HIGHEST RIDGES OVERNIGHT...CANNOT RULE OUT FLURRIES THROUGH 12Z.
DID NOT CHANGE TEMPERATURES TOO MUCH FROM PREVIOUS FORECAST. DID
GENERALLY NUDGE TOWARD LOWER MOS NUMBERS TODAY.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
WAS A BIT COOLER ON MAXIMUM TEMPERATURES ON TUESDAY...EVEN THOUGH
SOUTHERN AND WESTERN COUNTIES SHOULD SEE PLENTY OF AFTERNOON
SUNSHINE...THE 850 MB THERMAL TROF HANGS OVER US THROUGH 18Z. DID
INCREASE THE STRATOCUMULUS CLOUDS ON TUESDAY...ESPECIALLY NE OF
CRW. INCLUDED SOME SPRINKLES OR FLURRIES IN THE CKB TO EKN AND
CNTRL WV MOUNTAIN CORRIDOR INTO TUESDAY AFTERNOON. WINDS SHOULD
STILL BE QUITE NOTICEABLE DURING THE DAY.
PEACEFUL TUESDAY NIGHT STILL EXPECTED.
HIGH CLOUDS INCREASE WEDNESDAY...AND WITH LIGHT WINDS...HELD DOWN
TEMPERATURES A FEW DEGREES.
TIMING THE INITIAL PCPN STILL UNCERTAIN...SO NO REASON TO ADJUST
MUCH WITH WEDNESDAY NIGHT.
THE 00Z ECWMF HAS COME MORE IN LINE WITH THE GFS ON SPEED OF
SOUTHERN 500 MB TROF MOVING EAST. CANADIAN STILL A BIT SLOWER.
A GOOD SSW 850 MB FEED OF DEW POINTS AROUND 8C INTO AN EAST TO WEST
BAROCLINIC ZONE OVER US. SO A BIT CONCERNED AT THIS DISTANCE IN
TIME...ON SOME HEAVIER RAIN AND MAYBE WATER ISSUES. WILL INCREASE
POPS THURSDAY INTO THURSDAY EVENING TO LIKELY ESPECIALLY FOR MUCH OF
THE CWA.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LOTS OF VARIABILITY BETWEEN MODELS IN THIS PERIOD...LEADING TO A
LOW CONFIDENCE FORECAST. USED A BLEND OF THE GFS AND UKMET FOR
THURSDAY AND FRIDAY...THEN WENT MORE TOWARD THE GFS FOR SATURDAY AND
SUNDAY. THIS WOULD PROVIDE A SOUTHERN STREAM SYSTEM FOR WEDNESDAY
NIGHT AND THURSDAY...FOLLOWED BY ANOTHER FRIDAY NIGHT AND SATURDAY.
BEHIND THE SATURDAY SYSTEM...COLDER AIR MAY MOVE INTO THE REGION.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
WEAKENED CONVECTIVE LINE NOW APPROACHING THE TRI-STATE AREA.
LIGHTNING STRIKES HAVE DIMINISHED GREATLY...BUT THERE IS STILL
POTENTIAL FOR 30-40 KNOT GUSTS AS THE LINE PASSES. HAVE A 2 HOUR
WINDOW OF STRONG WIND GUSTS/TEMPO IFR CONDITIONS AT HTS/CRW/PKB/CKB
FOR THE CONVECTIVE LINE. THINK WINDS MIGHT WEAKEN A BIT AND DID NOT
PUT THE STRONG GUSTS IN EKN/BKW AT THIS TIME.
BEHIND THIS LINE...WINDS WILL CONTINUE TO GUST BETWEEN 20 AND 30
KNOTS IN ADVANCE OF ACTUAL COLD FRONT WHICH CROSSES DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. A FEW SCATTERED SHOWERS WILL
LINGER UNTIL FROPA. CIGS SHOULD IMPROVE TO LOW END VFR BY AFTERNOON
BEHIND THE INITIAL CONVECTION...AND IMPROVE FURTHER THIS EVENING AS
HIGH PRESSURE AND DRIER AIR WORK IN FROM THE SOUTHWEST.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: MVFR CIGS COULD LINGER A BIT LONGER THAN
CURRENTLY FORECAST. STRONG WIND GUSTS MAY NOT YET MATERIALIZE.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY L M M H M M M M H H H H
HTS CONSISTENCY L L L L L L M M H H H H
BKW CONSISTENCY L M L L M H H H M H M H
EKN CONSISTENCY L M L M H H M M M H M M
PKB CONSISTENCY L L M L L L L L H H H H
CKB CONSISTENCY L M M M H H M M H H M M
AFTER 18Z TUESDAY...
IFR POSSIBLE WEDNESDAY NIGHT AND THURSDAY IN LOW CLOUDS...RAIN...AND
FOG.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR WVZ005>011-
013>020-024>040-046-047.
OH...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR OHZ066-067-075-
076-083>087.
KY...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR KYZ101>103-105.
VA...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR VAZ003-004.
&&
$$
SYNOPSIS...KTB/CL
NEAR TERM...CL/SL
SHORT TERM...KTB
LONG TERM...RPY
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
637 AM CST MON JAN 23 2012
.UPDATE...BAND OF HEAVY SNOW SHIFTG THROUGH N-C WI NOW. IT APPEARS
2-3 INCHES HAS ALREADY FALLEN FM AUW NWD. LOOKS LIKE AREAS FROM
AUW NWD ARE HEADED TOWARD THE UPPER LIMITS OF THE SNOWFALL RANGES
WE HAVE IN GOING FCST. DON/T WANT TO OVERREACT THOUGH SINCE RADAR
SUGGESTS BEST SNOWS MOVG THROUGH NOW. NAM AND RUC BOTH SHOW VV/S
WEAKENING SUBSTANTIALLY BY MID-MORNING...WITH MODEST VALUES AT
BEST LINGERING NR THE UPPER MICHIGAN BORDER. THAT FITS WITH
COLDEST CLOUD TOPS LIFT THROUGH THAT AREA ON IR STLT NOW.
MAY NUDGE SNOWFALL TOTAL UP A BIT IN THE N. FARTHER S...IT/S
PROBABLY JUST A MATTER THAT WE/VE ALREADY RECEIVED MOST OF THE
SNOW WE ARE GOING TO GET. BEST OPTION THERE MAY BE TO REWORK FCST
TO CALL FOR LIMITED ADDITIONAL ACCUMULATIONS. PLAN TO SEND UPDATED
PRODUCT SUITE WITHIN ABOUT THE NEXT HALF HOUR.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 333 AM CST MON JAN 23 2012...
SYNOPSIS...WINTER WX ADVISORY WL REMAIN INTACT WITH THIS
ISSUANCE. MIXED PRECIPITATION CHANGING TO SNOW AND THEN ENDING
FROM SOUTHWEST TO NORTHEAST TODAY.
SPLIT FLOW WL DOMINATE THE CONUS FOR MUCH OF THE WEEK. BY NEXT
WEEKEND...RISING HEIGHTS OUT NR THE WEST COAST WL CAUSE THE
DOWNSTREAM FLOW TO CONSOLIDATE AGAIN...WITH BROAD TROF FORMING
OVER CEN/ERN NOAM.
MOST SIG PCPN EVENT WL BE WITH CYCLONE CROSSING THE RGN TDA...THEN
A PERIOD OF RELATIVELY QUIET WX EXPECTED AS THE FCST AREA IS
DOMINATED BY LOW-AMPLITUDE NRN STREAM THE REST OF THE WEEK. TEMPS
WL REMAIN ABV NORMAL MOST OF THE WK...THEN DROP BACK CLOSE TO
NORMAL AS BROAD UPR TROF DEVELOPS OVER THE FCST AREA NEXT WEEKEND.
SHORT TERM...TDA/TNGT/TUE. CYCLONE WL LIFT NEWD ACRS THE FCST
AREA THIS MORNING. DEEPENING MOISTURE...MID-LVL COOLING DUE TO
ASCENT...AND EVENTUALLY COLDER AIR WRAPPING ARND THE CYCLONE WL
RESULT IN DZ/FZDZ/RN CHANGING TO SN FM W TO E DURING THE DAY. THIS
WAS STARTING TO HAPPEN QUICKLY OVER WRN PARTS OF WI THIS MORNING.
SOUNDINGS CONSTRUCTED OFF RUC ANALYSES SUGGEST MUCH OF CENTRAL AND
N-C WL GO OVER TO SNOW ONCE BAND OF HEAVIER PCPN ARRIVES FROM THE
S. N-C WI AND PORTIONS OF NE WI WL NEED ADVISORY ALL DAY DUE TO
THE SNOW. NOT SURE SNOWFALLS WL JUSTIFY KEEPING ADVISORY GOING ALL
DAY OVER CENTRAL WI. BUT SNOW FALLING ON ICY ROADS WON/T BE
GOOD...SO TRAVEL CONDITIONS MAY REMAIN POOR. PLAN TO KEEP HEADLINE
INTACT WITH THE ISSUANCE AND JUST CANCEL EARLY IF/WHEN CONDITIONS
IMPROVE.
DENSE FOG COULD BE AN ISSUE IN THE E...ESP ALONG THE TRACKLINE OF
THE SFC LOW WHERE WINDS WL GO LGT FOR A TIME AS THE LOW CROSSES
THE AREA. BUT BAND OF HEAVIER PCPN THAT DEVELOPED DURING THE PAST
1-2 HRS WL WORK ACRS THIS AREA...HELPING TO MIX THE LOWER ATM.
SFC WINDS WERE ALSO LOSING THE SELY TRAJECTORY THAT WAS FEEDING
HIGHER DWPTS INTO THE AREA. BEST COURSE OF ACTION SEEM TO BE TO
GO WITH AREAS OF DENSE FOG IN THE GRIDS/ZONES...BUT FOREGO
ADVISORY SINCE IT DOESN/T APPEAR LOW VSBYS WL BE WIDESPREAD ENOUGH
TO WARRANT AN ADVISORY.
TRAJECTORIES LOOK FAVORABLE FOR SOME LAKE-EFFECT IN NORTH-CENTRAL
WI THIS AFTN INTO EARLY EVENING. LAKE SURFACE/AIR TEMPERATURE
DIFFERENCE SOMEWHAT MARGINAL...BUT PLENTY OF MOISTURE LINGERING FM
DEPARTING SYSTEM MAY OFFSET THAT. OTHER THAN THE LAKE-EFFECT...
PCPN SHOULD DIMINISH MOST AREAS BY EARLY EVENING.
CLDS LIKELY TO LINGER TNGT...WITH THE BEST CHC FOR BREAKS IN THE
TYPICAL NW-FLOW DOWNSLOPE AREA OVER THE NE.
HIGH TEMPS WL OCCUR EARLY TDA...FOLLOWED BY SLOWLY FALLING TEMPS.
BUT THE AIR BEHIND THE SYSTEM ISN/T REAL COLD...SO LINGERING
MOISTURE ON ROADWAYS SHOULD HAVE A CHC TO EVAPORATE BEFORE CAN
FREEZE. EDGED MINS UP A BIT TNGT...THEN WENT WITH BLEND OF BEST
PERFORMING GUID FOR MAXES TUE.
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY.
THE UPPER FLOW WILL BE TRANSITIONING OVER THE PERIOD FROM A FAST
ZONAL PATTERN...TO BUCKLED NORTHWEST FLOW. AS A RESULT...MILD
PACIFIC DOMINATED AIRMASSES THROUGH THE END OF THIS WEEK WILL RETURN
TO THE POLAR VARIETY. A COUPLE OF MINOR SYSTEMS TO DEAL WITH
THROUGH THE EXTENDED. SIMILAR TO LAST NIGHT PREFER THE GFS FOR THE
SHORTWAVE LATE WEDNESDAY NIGHT INTO THURSDAY WITH THE FAST FLOW IN
PLACE. THEREAFTER...A CLIPPER SYSTEM WILL ARRIVE ON SATURDAY WHICH
WILL BE THE LEADING EDGE OF ARCTIC AIR. BOTH THE GFS AND ECMWF
HANDLE THIS FEATURE COMPARABLY...SO WILL BLEND THE TWO SOLUTIONS.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...WEAK SHEARED SHORTWAVE
WILL BE CROSSING THE REGION LATE TUESDAY NIGHT INTO EARLY WEDNESDAY
MORNING. MID AND HIGH CLOUDS WILL BE ON THE INCREASE TUESDAY NIGHT
AHEAD OF THE WAVE...BUT LOW LEVELS STRUGGLE TO SATURATE. SUPPOSE
THERE COULD BE A FLURRY OR TWO OUT OF THE MID-DECK BUT THATS MORE OF
A SHORT TERM CONCERN SO WILL LEAVE THE FORECAST DRY. SKIES WILL BE
CLEARING ON WEDNESDAY AS THE FIRST SHORTWAVE DEPARTS. HIGHS WILL BE
MILD WITHIN A PACIFIC AIRMASS WITH READINGS AROUND THE FREEZING
MARK. CLOUDS WILL BE ON THE INCREASE AGAIN WEDNESDAY NIGHT AHEAD OF
A MORE DYNAMIC SHORTWAVE. NOT SEEING THE GOOD MID-LEVEL LAPSE RATES
LIKE LAST NIGHT...BUT MID AND UPPER FORCING IS DECENT. STILL
LOOKING AT DRY WEDGES HOWEVER IN THE LOW AND MID-LEVELS WITH
MOISTURE PROFILES FAILING TO SATURATE. WILL AGAIN TREAT THIS AS A
SHORT TERM CONCERN AND REMOVE POPS.
REST OF THE FORECAST...THE SHORTWAVE TROUGH WILL FINISH CROSSING THE
REGION THURSDAY MORNING AND WILL AGAIN REMOVE THE SLIGHT CHANCE OF
PRECIP. SHOULD SEE SOME SUN MOVE IN FOR THE AFTERNOON WITH TEMPS
SLIGHTLY ABOVE FREEZING. NORTHWEST FLOW ALOFT WILL BE STRENGTHENING
THURSDAY NIGHT INTO FRIDAY...WHEN WILL HAVE WEAK COLD ADVECTION AND
BREEZY CONDITIONS OVER THE PERIOD...BUT NO PRECIP THREAT OF
SIGNIFICANCE. RATHER STRONG SHORTWAVE WILL BE MOVING ACROSS THE
REGION FRIDAY NIGHT...WHICH WILL BE THE LEADING EDGE OF AN ARCTIC
AIRMASS. TEMPERATURES WILL FALL BACK TO OR BELOW NORMAL WHILE WINDS
WILL BE PRETTY BRISK. CAN ENVISION OCCASIONAL SNOW FLURRIES OR
LIGHT SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY AS THE UPPER TROUGH
SWINGS OVERHEAD. CURRENT FORECAST IS DRY...BUT WILL JUST MENTION TO
LATER SHIFTS. COLD AND DRY CONDITIONS ON SUNDAY...AND POSSIBLY SOME
LIGHT SNOW ON MONDAY AS ANOTHER CLIPPER SYSTEM MOVES THROUGH THE
REGION.
&&
.AVIATION...FOR 12Z TAF ISSUANCE...LIFR/VLIFR CONDITIONS
WIDESPREAD ACRS THE AREA THIS MORNING. CONDITIONS SHOULD START TO
IMPROVE LATER TDA ONCE THE LOW PULLS OFF TO THE NE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ005-
010>013-018>021-030-031-035>037-045.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
535 AM CST MON JAN 23 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
245 AM CST MON JAN 23 2012
FORECAST CONCERNS FOCUS ON THE SNOW THIS MORNING.
LATEST WATERVAPOR IMAGERY DEPICTED AN UPPER LEVEL SHORTWAVE TROUGH
CHURNING ACROSS THE SOUTHERN PLAINS...WHILE AT THE SFC A LOW WAS
LOCATED OVER NORTHERN MO. 88-D RADAR IMAGERY SHOWED AREAS OF PCPN
SPREADING FROM THE DAKOTAS ACROSS MN/IA...AND ACROSS SOUTHERN WI AND
ILL. WHAT WAS FALLING WAS DEPENDENT ON SFC TEMPS AND WHETHER OR NOT
ANY ICE WAS IN THE CLOUD.
23.00Z ARE IN GOOD AGREEMENT WITH LIFTING THE TROUGH NORTHEAST
ACROSS THE REGION TODAY...AND OVER SOUTHEAST CANADA TONIGHT. THE
BULK OF THE ASSOCIATED QG CONVERGENCE WITH THE UPPER LEVEL FORCING
EXITS THE FORECAST AREA BY 18Z...AS DOES ANY ISENTROPIC UPGLIDE ON
THE 275-295 K SFCS. X-SECTIONS POINT TO SOME 2-D FRONTOGENETIC
FORCING...BUT THIS ALSO LIFTS TO THE NORTHEAST BY 18Z.
AS IT LOOKS NOW...THE BULK OF ANY ACCUMULATING PCPN SHOULD BE THIS
MORNING...WITH PERHAPS SOME LIGHT PCPN LINGERING INTO THE AFTERNOON
ACROSS NORTHERN AREAS. RUC13 BUFKIT SOUNDINGS SATURATE ENOUGH THAT
ICE IS INTRODUCED INTO THE CLOUD BY 3 AM...SO SNOW SHOULD BE THE
MAIN PCPN TYPE. MAIN MASS OF PCPN MOVING ACROSS THE REGION IS
ASSOCIATED WITH THE UPPER LEVEL TROUGH/QG CONVERGENCE. THE
DEFORMATION BAND NORTHWEST OF THE LOW HAS TWO AREAS...ONE FAIRLY
NARROW. THIS WAS IMPACTING WESTERN MN/WESTERN IA. THE MISH-MASH OF
DIFFERENT AREAS MAKES IT HARDER TO REFINE SNOW AMOUNTS FOR THIS
MORNING...BUT LOCATIONS TO THE WEST AND NORTH WILL HAVE SNOW FOR A
BIT LONGER...AND SLIGHTLY HIGHER AMOUNTS SHOULD BE FAVORED. OVERALL
1 TO 3 INCHES STILL LOOKS REASONABLE.
ON TOP OF THE SNOW THE STORM SYSTEM WILL BRING SOME BLUSTERY
CONDITIONS. TIGHTENING PRESSURE GRADIENT WILL RESULT IN NORTHWEST
WINDS OF 15 TO 25 MPH WITH GUSTS OF 30 TO 35 IN THE
OPEN/UNSHELTERED AREAS OF SOUTHEAST MN/NORTHEAST IA. THIS COULD
CAUSE SOME BLOWING OF THE FRESHLY FALLEN SNOW. THE PREVIOUS SNOW
COVER WILL BE HELD IN PLACE BY THE LIGHT GLAZING OF ICE FROM
YESTERDAY/S FREEZING DRIZZLE. LOW LEVEL COLD AIR ADVECTION WILL KEEP
TEMPERATURES STEADY...OR SLOWLY FALL. TODAY/S HIGH HAVE PROBABLY
ALREADY OCCURRED.
AS FOR THE WINTER WEATHER ADVISORY...WITH SNOW JUST MOVING IN...WILL
CONTINUE THE ADVISORY. THE NORTHERN PORTION OF THE ADVISORY MAY BE
ABLE TO BE CANCELLED BEFORE THE 6 PM EXPIRATION.
.LONG TERM...THURSDAY THROUGH SUNDAY
245 AM CST MON JAN 23 2012
MODELS POINT TO A MOSTLY ZONAL TO SOMEWHAT NORTHWEST UPPER LEVEL
FLOW THROUGH THE WEEKEND. BITS OF SHORTWAVE ENERGY WILL TRAVEL ALONG
THE FLOW...WITH DECENT AGREEMENT BETWEEN THE GFS AND EC WITH SLIDING
A TROUGH ACROSS THE UPPER MISSISSIPPI RIVER VALLEY WED NIGHT/THU.
THE BRUNT OF THE QPF STAYS NORTH OF THE FORECAST AREA
HOWEVER...ALTHOUGH A TIGHTENING PRESSURE GRADIENT WILL RESULT IN
SOME BLUSTERY CONDITIONS. OVERALL...THE PERIOD IS STILL TRENDING DRY
WITH TEMPS AT OR ABOVE THE SEASONABLE NORMALS.
&&
.AVIATION...TODAY AND TONIGHT
535 AM CST MON JAN 23 2012
LIGHT SNOW WILL CONTINUE TO FALL THROUGH THIS MORNING THEN COME TO
AN END AT KRST AND KLSE AROUND 18Z AS DEEP LOW PRESSURE LIFTS
NORTHWARD INTO UPPER MICHIGAN. TOTAL ACCUMULATIONS OF 2-3 INCHES
CAN BE EXPECTED AT KRST WITH 1-2 INCHES EXPECTED AT KLSE. SOME
BLOWING SNOW CAN ALSO BE EXPECTED AT KRST AS NORTHWEST WINDS GUST
UP TO 30 KT. LOOK FOR IFR CONDITIONS THIS MORNING IMPROVE INTO
MVFR CATEGORY BY 18Z. MVFR STRATUS EXPECTED TO LINGER THROUGH
TONIGHT WITH WINDS SLOWLY DIMINISHING AFTER SUNSET.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
245 PM CST MON JAN 23 2012
WI...WINTER WEATHER ADVISORY UNTIL NOON CST FOR WIZ032>034-
041>044-053>055-061.
WINTER WEATHER ADVISORY UNTIL 6 PM CST FOR WIZ017-029.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST FOR MNZ079-086>088-
094>096.
IA...WINTER WEATHER ADVISORY UNTIL NOON CST FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS PUEBLO CO
321 PM MST MON JAN 23 2012
.SHORT TERM...
(TONIGHT AND TUESDAY)
CURRENT WATER VAPOR IMAGERY AND RUC80 DATA SHOW THE APPROACHING
STORM SYSTEM OVER CENTRAL NEVADA AT THIS TIME. THE 12Z NAM12 AND
GFS FORECAST THE LOW TO MOVE SOUTH OF THE FOUR CORNERS AREA INTO
SOUTHWESTERN NEW MEXICO BY 18Z TUESDAY.
12Z NAM12 AND GFS AND THE 17Z HRRR SHOW SNOW BEGINNING IN THE
SOUTHWESTERN MOUNTAINS BETWEEN 01Z AND 02Z TUESDAY. I DECIDED TO
BLEND THE 12Z NAM12 AND GFS (THE NAM12 BEING THE HEAVIEST ON QPF AND
THE GFS BEING THE LIGHTEST)...AND HAVE ISSUED A WINTER WEATHER
ADVISORY FOR THE SAN JUAN MOUNTAINS BEGINNING AT 01Z. CURRENT TOTAL
SNOW GRID SHOWS FIVE TO SEVEN INCHES OF SNOW ON THE HIGHEST PEAKS OF
THE SAN JUANS. WITH THE UPPER LOW PASSING WELL TO THE SOUTH AND
SOUTHWEST UPLOPE FLOW ON THE WEAK SIDE...SNOW TOTALS ARE ON THE LOW
SIDE OF ADVISORY CRITERIA...BUT FEEL AT LEAST THE PEAKS WILL REACH
ADVISORY CRITERIA.
THE SANGRES...ESPECIALLY THE SOUTHERN PEAKS...WILL ALSO RECEIVE LIGHT
TO MODERATE SNOWS (3-5 INCHES)...BUT WILL REMAIN BELOW ADVISORY
CRITERIA DURING THIS EVENT...AS WILL THE EASTERN SAWATCH AND WESTERN
MOSQUITOES RANGES. THE SAN LUIS VALLEY WILL ONLY LIKELY SEE A DUSTING
OF SNOW.
THE INTERSTATE 25 CORRIDOR AND EASTERN PLAINS WILL LIKELY NOT SEE
ANY APPRECIABLE PRECIPITATION FROM THIS SYSTEM WITH ONLY 50 POPS IN
THE GRIDS FOR COS AND PUB AND ISOLATED POPS FOR THE EASTERN PLAINS.
PRECIPITATION WILL QUICKLY DISSIPATE FROM NORTH TO SOUTH AFTER 18Z
AS THE THEN CLOSED 500MB LOW MOVES WELL SOUTH OF THE FORECAST
AREA.
.LONG TERM...
(TUESDAY NIGHT THROUGH MONDAY)
TUESDAY NIGHT-THURSDAY...MODERATE NORTH TO NORTHWEST FLOW ALOFT
ACROSS THE REGION TUESDAY NIGHT AND WEDNESDAY BEHIND PASSING UPPER
TROUGH BECOMES MORE WESTERLY WEDNESDAY NIGHT AND THURSDAY AS UPPER
LEVEL RIDGING BUILDS ACROSS THE STATE. GENERALLY LIGHT PRECIPITATION
ONGOING ACROSS THE SOUTHEAST MOUNTAINS AND FAR SE PLAINS TUESDAY
AFTERNOON LOOKS TO DIMINISH TUESDAY EVENING WITH SKIES CLEARING FROM
WEST TO EAST TUESDAY NIGHT. THERE REMAINS SOME MODEL DIFFERENCES ON
NORTHERN EXTENT OF DEFORMATION BAND PRECIP SHIELD ASSOCIATED WITH
UPPER LOW MOVING EAST ACROSS CENTRAL NEW MEXICO...WITH THE LATEST
GFS AND ECMWF KEEPING ANY PRECIPITATION WELL SOUTH AND EAST OF THE
AREA. THE NAM CONTINUES TO DEVELOP PRECIP ACROSS THE WESTERN TX/OK
PANHANDLE WHICH SLIDES NORTH AND EAST INTO SOUTHEASTERN COLORADO
TUESDAY NIGHT. AT ANY RATE...HAVE KEPT SLIGHT POPS ACROSS MAINLY
SOUTHERN BACA COUNTY TO ACCOUNT FOR THIS...WHICH ALSO BLENDS BETTER
WITH SURROUNDING OFFICES. DRY WEATHER WITH ABOVE SEASONAL
TEMPERATURES IS THEN EXPECTED ACROSS THE AREA FOR WEDNESDAY AND
THURSDAY UNDER THE BUILDING RIDGE. THURSDAY STILL LOOKS TO BE THE
WARMEST DAY OF THE WEEK...THOUGH TEMPERATURES MAY BE TEMPERED BY
INCREASING HIGH LEVEL CLOUDS STREAMING ACROSS THE AREA THROUGH THE
AFTERNOON.
THURSDAY NIGHT-FRIDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT
OF WIDESPREAD SNOWFALL DEVELOPING ACROSS HIGHER TERRAIN AND
IMMEDIATE ADJACENT PLAINS THROUGH THIS PERIOD...AS A SHORT WAVE
EMBEDDED WITHIN THE MODERATE WESTERLY FLOW ALOFT MOVES ACROSS THE
ROCKIES. QUICK MOVEMENT OF SYSTEM LIMITS SNOW DURATION...THOUGH SHOULD
AT LEAST SEE SOME LIGHT ACCUMULATIONS ACROSS THE CENTRAL MTS
THROUGH THE EASTERN MTS...ALONG WITH THE PALMER DIVIDE AND RATON
MESA...AS NORTH TO NORTHEAST SFC-H7 FLOW DEVELOPS THROUGH THE DAY.
SYSTEM SENDS A FAIRLY STRONG COLD FRONT ACROSS THE AREA THURSDAY
NIGHT AND EARLY FRIDAY...WITH HIGHS FRIDAY LIKELY EARLY IN THE
MORNING WITH STEADY AND FALLING TEMPERATURES INTO THE AFTERNOON.
SATURDAY-MONDAY...MODERATE WEST TO NORTHWEST CONTINUES ACROSS THE
REGION THROUGH THE REST OF THE EXTENDED PERIOD WITH LATEST MODELS
STILL INDICATING DIFFERENCES IN HARD TIME SHORT WAVES TRANSLATING
THROUGH THE FLOW. WITH TIMING DIFFERENCES...HAVE KEPT CURRENT
ISOLATED POPS ACROSS MAINLY THE CENTRAL MTS THROUGH THE PERIOD ALONG
WITH AT OR ABOVE SEASONAL TEMPERATURES. -MW
&&
.AVIATION...
LOWERING CIGS EXPECTED TONIGHT...ESPECIALLY ACROSS THE WESTERN
MOUNTAINS AND SAN LUIS VALLEY WITH CIGS DROPPING INTO THE MVFR
CATEGORY AFTER 09Z AT KALS. -SHSN WILL BE POSSIBLE FROM
09Z-17Z...WITH ANY ACCUMULATIONS EXPECTED TO REMAIN UNDER AN
INCH.
FOR KCOS AND KPUB...VFR CIGS WILL SPREAD INTO BOTH TAF SITES LATE
TONIGHT WITH GUSTY NORTH WINDS 10-20 KTS ASSOCIATED WITH A COLD
FRONT SPREADING INTO KCOS AND KPUB BETWEEN 15-17Z TUES. CIGS WILL
CONTINUE TO LOWER FOR BOTH TAF SITES DURING THE LATE MORNING/EARLY
AFTERNOON...DROPPING INTO THE MVFR CATEGORY. MTN OBSCURATIONS ARE
EXPECTED FOR THE SE MTS BY AFTERNOON WITH ISOLATED LIGHT SNOW
SHOWERS POSSIBLE FOR LOCATIONS NEAR THE MTS. DUE TO LOW PROBABILITY
OF -SHSN AFFECTING THE TAF SITES...WILL KEEP VCSH IN KCOS AND KPUB
TAFS FOR NOW.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 11 AM MST
TUESDAY FOR COZ068.
&&
$$
81/23
AREA FORECAST DISCUSSION
NWS ALBANY NY
1244 PM EST MON JAN 23 2012
.SYNOPSIS...
AFTER SOME LIGHT ICING CONDITIONS THROUGH EARLY THIS AFTERNOON
ACROSS AREAS NORTH AND EAST OF ALBANY...TEMPERATURES WILL CLIMB TO
ABOVE FREEZING AND PRODUCE MAINLY RAIN SHOWERS THAT WILL ACCOMPANY A
FRONTAL BOUNDARY AS IT CROSSES THE REGION. SOMEWHAT COOLER AIR WILL
FILTER IN FOR TUESDAY WITH SOME LAKE EFFECT SNOW DOWNWIND OF LAKE
ONTARIO. THERE WILL BE TRANQUIL CONDITIONS FOR THE MID WEEK AS A
RIDGE OF HIGH PRESSURE TRACKS ACROSS THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD TEMPS PERSIST ACROSS WESTERN NEW ENGLAND ZONES SO HAVE EXTENDED
THE FREEZING RAIN ADVISORY THERE THROUGH 200 PM. TEMPS IN THE
IMMEDIATE CONNECTICUT VALLEY OF EASTERN WINDHAM COUNTY MAY STILL BE
BELOW FREEZING AT THAT TIME...BUT WILL WAIT UNTIL THEN TO DECIDE ON
ANY ADDITIONAL EXTENSIONS OF THE ADVISORY. ELSEWHWERE ADVISORIES
HAVE BEEND ALLOWED TO EXPITE ACROSS THE MOHAWK/SCHOHARIE VALLEYS...
EASTERN CATSKILLS...CAPITAL DISTRICT AND TACONICS. HAVE CANCELLED
THE ADVISORY ACROSS ALL OF HERKIMER COUNTY SINCE MESONET OBS
INDICATE THE FAR WESTERN ADIRONDACKS HAVE WARMED TO ABOVE FREEZING.
THE ADVISORY CONTINUES FOR THE REST OF THE ADIRONDACKS AND LAKE
GEORGE REGION THROUGH 200 PM.
****PREVIOUS DISCUSSION****
AS OF 11 AM EST...HAVE DROPPED FREEZING RAIN ADVISORY FOR THE MID
HUDSON VALLEY REGION...WHERE TEMPS HAVE WARMED ABOVE FREEZING.
ELSEWHERE...HAVE KEPT FREEZING RAIN ADVISORIES IN PLACE...ALTHOUGH
TEMPS NOW RISING TO NEAR OR ABOVE FREEZING ACROSS THE EASTERN
CATSKILLS...SCHOHARIE VALLEY...AND THE CAPITAL REGION.
FURTHER N AND E...COLD AIR HANGING TOUGH...FROM SE VT INTO THE
BERKSHIRES AND SOUTH INTO EASTERN LITCHFIELD COUNTY...WHERE
DRIZZLE PERSISTS. WE MAY NEED TO EXTEND THE ADVISORIES FOR
PORTIONS OF THESE AREAS...AS COLD AIR MAY REMAIN TOUGH TO
DISLODGE.
STEADIER RAIN SHOULD DEVELOP FROM W TO E DURING THE MID TO LATE
AFTERNOON HOURS. THERE IS SOME POSSIBILITY THAT POCKETS OF
SUBFREEZING TEMPS PERSIST IN PORTIONS OF SE VT AND/OR THE
BERKSHIRES WHEN THIS ARRIVES...SO WILL NEED TO MONITOR CLOSELY.
PREVIOUS DISCUSSION FOLLOWS...
AS OF 6 AM...DRIZZLE IS BEGINNING TO SHOW UP ACROSS THE TRI-STATE
REGION AND MID-HUDSON VALLEY INCLUDING OUR RADAR IN VCP31.
TEMPERATURES VARY BUT THEY DO HOVER AROUND THE FREEZING MARK WHERE
DRIZZLE IS BEING REPORTED. NCEP MODEL SUITE ALONG WITH THE
RUC13/HRRR NOT DOING THAT WELL...HOWEVER...THEY DO SUGGEST THIS
AREA OF DRIZZLE AND SATURATING BOUNDARY LAYER ADVANCES SLOWLY
NORTH THIS MORNING. WET BULB PROFILES ARE STILL BELOW FREEZING SO
WE WILL CONTINUE WITH THE ADVISORY AND REFRESH THE GRIDS AND
HOURLY TEMPS/DEWPTS. PER THE 06Z MOS AND HOURLY LAV/LAMP...MOST
AREAS WILL CLIMB ABOVE FREEZING AROUND THE NOON HOUR.
PREV DISC...
VERY CHALLENGING NEAR TERM FORECAST AS FZDZ HAS NOT
MATERIALIZED AT THIS TIME. PER METARS...THE CIGS REMAIN RATHER
HIGH AND DEWPOINT DEPRESSIONS ARE 5 DEGREES OR GREATER. WE DID
RECEIVE A REPORT OF FLURRIES IN LITCHFIELD COUNTY AND THIS CAN
ALSO BE CONFIRMED WITH SEVERAL METARS ACROSS THE NYC METRO AREA
REPORTING LIGHT SNOW. THIS MAY BE DUE TO THE OCEANIC EFFECT ADDING
ENOUGH NUCLEI TO RESULT IN THOSE OBS OF LIGHT SNOW. THE FORECAST
SOUNDINGS ACROSS OUR REGION STILL SUGGEST THE BOUNDARY LAYER WILL
MOISTEN UP BELOW THE -10C ISOTHERM INCLUDING THE SHEAR PROFILES
FOR SOME DRIZZLE FORMATION. RUC13 FORECAST SOUNDINGS DELAY THE
ONSET OF MOISTURE UNTIL THE 12-15Z TIME FRAME. BY THAT
TIME...TEMPERATURES ARE BEGINNING TO CLIMB TO AT OR ABOVE FREEZING
ALONG AND SOUTH OF I90. THE COLDER AIR IS EXPECTED TO REMAIN IN
PLACE LONGER ACROSS THE DACKS...LAKE GEORGE SARATOGA REGION AND
SOUTHERN VERMONT UNTIL ABOUT THE NOON HOUR. THE ADVISORY LOOKS
GOOD AT THIS TIME WITH NO CHANGES EXPECTED.
POTENT SHORT WAVE TRACKING NORTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY INTO THE GREAT LAKES REGION WILL SEND A COLD FRONT EASTWARD
THIS AFTERNOON. A BAND OF BKN SHOWERS IS EXPECTED AND WE WILL
PLACE CATEGORICAL POPS FOR THE ENTIRE REGION. TIMING OF THIS FRONT
APPEARS TO BE AOA 21Z. AS FOR CONVECTIVE POTENTIAL /IE
THUNDER/...THE SHOWALTER INDEX IS EXPECTED TO DROP TOWARD 0C FOR
PORTIONS OF THE REGION WITH THE BEST UPPER SUPPORT FOR THE WESTERN
MOHAWK VALLEY AND DACKS. WHILE WE WILL NOT INCLUDE THUNDER...WOULD
NOT TOTALLY RULE OUT A RUMBLE OF THUNDER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
WITH FROPA...DRY SLOT QUICKLY APPROACHES THIS EARLY EVENING. SOME
LINGERING UPSLOPE SHOWERS ARE EXPECTED BUT THIS TOO SHOULD
DECREASE THROUGH TONIGHT. SEEMS THE INITIAL COLD ADVECTION WILL
REMAIN WEST OF THE HUDSON RIVER VALLEY WITH TEMPERATURES OVERNIGHT
REMAINING ABOVE FREEZING FOR A GOOD PORTION OF THE REGION. THE
EXCEPTION TO THIS WILL BE FOR PORTIONS OF THE DACKS. LAKE ONTARIO
CONTRIBUTION INCREASES A BIT...ALBEIT MARGINALLY...TO WARRANT
CHANCE POPS FOR RAIN/SNOW SHOWERS TRANSITIONING TO SNOW SHOWER
OVERNIGHT.
DUE TO A RELATIVELY MILDER START TO THE DAY TUESDAY...TEMPERATURES
FOR THE REGION SHOULD ONCE AGAIN CLIMB ABOVE THE FREEZING WITH MID
40S EXPECTED FOR THE MID HUDSON RIVER VALLEY AND NW CT. CYCLONIC
FLOW REMAINS OVER LAKE ONTARIO AND THE DACKS WITH A VEERING WIND
PROFILE TO TAKE WHAT BANDS OF LAKE EFFECT ACTIVITY FURTHER SOUTH.
SECONDARY COLD FRONT IS EXPECTED TO CLEAR THE REGION LATE TUESDAY
AFTERNOON WITH 850MB TEMPS EXPECTED TO PLUNGE BACK BELOW -10C FOR
THE ENTIRE CWA. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A BRIEF
ORGANIZED LAKE EFFECT WITH CLIMBING INVERSION HEIGHTS TUESDAY
EVENING BEFORE FALLING ONCE AGAIN OVERNIGHT. AT THIS POINT...SEEMS
ACCUMULATIONS WILL BE LIMITED AND ISOLATED WITH GENERALLY AROUND 1
INCH. AS UPPER TROUGH SLIDES EAST OF THE REGION...INVERSION
HEIGHTS DROP QUICKLY AS DOES THE DRY AIR ADVECTION ACROSS NY
STATE.
A NARROW SURFACE RIDGE IS EXPECTED ACROSS THE REGION DESPITE
ANOTHER SHORT WAVE MOVING ACROSS THE NORTHERN TIER OF NY AND NEW
ENGLAND. WITH LIMITED MOISTURE...WE WILL KEEP SKIES PTCLOUDY AND
NO MENTION OF PRECIP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE PERIOD WILL START OUT WITH A RIDGE MOVING ACROSS THE REGION AT
THE SURFACE WITH THE FLOW ALOFT FLATTENING. THE MODELS ARE IN FAIRLY
GOOD AGREEMENT WITH THE LONGWAVE PATTERN...HOWEVER THERE ARE
DIFFERENCES IN THE TIMING AND TRACK OF THE SOUTHERN STREAM SYSTEM
WHICH ORIGINATES OVER THE SOUTHERN PLAINS AND HEADS OUR WAY LATE IN
THE WEEK. THERE IS A QUESTION OF HOW MUCH INTERACTION THERE WILL BE
WITH THE NORTHERN STREAM. AT THIS TIME...THIS SYSTEM IS EXPECTED TO
PASS TO SOUTH BRINGING THE CHANCES FOR PRECIPITATION TO THE AREA
THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO RUN ABOVE
NORMAL WITH THE LONGWAVE PATTERN KEEPING THE COLDER AIR TO OUR NORTH
THROUGH THE WORK WEEK. INDICATIONS ARE NORTHERN STREAM ENERGY WILL
DIVE INTO THE NORTHERN PLAINS CAUSING A TROUGH TO DIG OVER THE
EASTERN UNITED STATES OVER THE WEEKEND RETURNING MORE SEASONABLE AIR
TO THE REGION.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
CONDITIONS WILL REMAIN MAINLY IFR FOR VSBYS AND CIGS THROUGH THIS
EVENING...ALTHOUGH IT MAY TAKE ANOTHER HOUR OR TWO TO DROP INTO
IFR RANGE AT KGFL WHERE SOME DRIER LOW LEVEL AIR PERSISTS. EXPECT
MAINLY IFR CONDITIONS OVERNIGHT...LIFTING INTO MVFR TOWARD
OR AROUND DAYBREAK. CONDITIONS SHOULD IMPROVE TO VFR BY MID
MORNING TUESDAY.
AS FOR PRECIPITATION...AREAS OF DRIZZLE WILL CONTINUE THROUGH MID
AFTERNOON. THEN...LIGHT TO MODERATE RAIN SHOULD DEVELOP FROM W TO
E DURING THE MID TO LATE AFTERNOON...BEFORE ENDING FROM SW TO NE
THIS EVENING. ISOLATED RAIN SHOWERS MAY PERSIST UNTIL LATE TONIGHT.
WINDS WILL REMAIN LIGHT...MAINLY FROM THE SE TO S AT 5-10 KT BY
LATE AFTERNOON THROUGH OVERNIGHT. HOWEVER...A PERIOD OF LIGHT
NORTH WINDS MAY CONTINUE AT KPOU...AND POSSIBLY KGFL THROUGH MID
AFTERNOON UNTIL THE LOW LEVEL GRADIENT TIGHTENS. EXPECT WINDS TO
SHIFT INTO THE SW...THEN W TUE MORNING...AT 5-10 KT...ALTHOUGH
SOME GUSTS OF UP TO 20 KT WILL BE POSSIBLE.
LOW LEVEL WIND SHEAR IS LIKELY THROUGH EARLY TONIGHT...AS SFC
WINDS REMAIN LIGHT FROM THE SE AT LESS THAN 8 KT...WHILE WINDS
AROUND 2000 FT AGL INCREASE FROM THE S TO 30-40 KT.
OUTLOOK...
TUE-WED...VFR. NO SIG WX.
THU...MAINLY VFR. CHC -RA/-SN BY LATE IN THE AFTERNOON.
THU NIGHT-SAT..VFR/MVFR. CHC -SHSN/-SHRA.
&&
.HYDROLOGY...
A STORM SYSTEM WILL BRING MIXED PRECIPITATION CHANGING TO RAIN
TODAY. A QUICK SHOT OF MODERATE TO HEAVY RAIN IS POSSIBLE THIS
AFTERNOON WITH A COLD FRONT AS QPF VALUES ARE EXPECTED TO BE BETWEEN
ONE QUARTER TO ONE HALF INCH WITH LOCALIZED AMOUNTS AROUND AN INCH
POSSIBLE INTO THE HIGHER TERRAIN OF THE CATSKILLS...SOUTHERN VERMONT
AND BERKSHIRES.
WE MEASURED THE GROUND FROZEN TO A DEPTH OF 14 INCHES HERE AT THE
OFFICE ON SUNDAY. SOME LOCALIZED POOR DRAINAGE...URBAN AND SMALL
STREAM FLOODING MAY BE POSSIBLE LATER MONDAY DUE TO ENHANCED RUNOFF
FROM RAIN AND MELT ON FROZEN GROUND.
SOME SIGNIFICANT RISES ON MAIN STEM RIVERS ARE POSSIBLE MONDAY INTO
TUESDAY...BUT LARGER RIVER FLOODING IS NOT EXPECTED AT THIS TIME.
RISES WOULD BE ENOUGH TO BREAK UP WHAT RIVER ICE IS IN PLACE BUT ICE
IS NOT THICK ENOUGH TO CAUSE SIGNIFICANT ICE JAM PROBLEMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
CTZ001-013.
NY...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NYZ033-041>043-082>084.
MA...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MAZ001-025.
VT...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
VTZ013>015.
&&
$$
SYNOPSIS...KL/BGM
NEAR TERM...GJM/KL/BGM
SHORT TERM...BGM
LONG TERM...IAA
AVIATION...KL/IAA
HYDROLOGY...SND/BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
1225 PM EST MON JAN 23 2012
.SYNOPSIS...
AFTER SOME LIGHT ICING CONDITIONS THROUGH EARLY THIS AFTERNOON
ACROSS AREAS NORTH AND EAST OF ALBANY...TEMPERATURES WILL CLIMB TO
ABOVE FREEZING AND PRODUCE MAINLY RAIN SHOWERS THAT WILL ACCOMPANY A
FRONTAL BOUNDARY AS IT CROSSES THE REGION. SOMEWHAT COOLER AIR WILL
FILTER IN FOR TUESDAY WITH SOME LAKE EFFECT SNOW DOWNWIND OF LAKE
ONTARIO. THERE WILL BE TRANQUIL CONDITIONS FOR THE MID WEEK AS A
RIDGE OF HIGH PRESSURE TRACKS ACROSS THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD TEMPS PERSIST ACROSS WESTERN NEW ENGLAND ZONES SO HAVE EXTENDED
THE FREEZING RAIN ADVISORY THERE THROUGH 200 PM. TEMPS IN THE
IMMEDIATE CONNECTICUT VALLEY OF EASTERN WINDHAM COUNTY MAY STILL BE
BELOW FREEZING AT THAT TIME...BUT WILL WAIT UNTIL THEN TO DECIDE ON
ANY ADDITIONAL EXTENSIONS OF THE ADVISORY. ELSEWHWERE ADVISORIES
HAVE BEEND ALLOWED TO EXPITE ACROSS THE MOHAWK/SCHOHARIE VALLEYS...
EASTERN CATSKILLS...CAPITAL DISTRICT AND TACONICS. HAVE CANCELLED
THE ADVISORY ACROSS ALL OF HERKIMER COUNTY SINCE MESONET OBS
INDICATE THE FAR WESTERN ADIRONDACKS HAVE WARMED TO ABOVE FREEZING.
THE ADVISORY CONTINUES FOR THE REST OF THE ADIRONDACKS AND LAKE
GEORGE REGION THROUGH 200 PM.
****PREVIOUS DISCUSSION****
AS OF 11 AM EST...HAVE DROPPED FREEZING RAIN ADVISORY FOR THE MID
HUDSON VALLEY REGION...WHERE TEMPS HAVE WARMED ABOVE FREEZING.
ELSEWHERE...HAVE KEPT FREEZING RAIN ADVISORIES IN PLACE...ALTHOUGH
TEMPS NOW RISING TO NEAR OR ABOVE FREEZING ACROSS THE EASTERN
CATSKILLS...SCHOHARIE VALLEY...AND THE CAPITAL REGION.
FURTHER N AND E...COLD AIR HANGING TOUGH...FROM SE VT INTO THE
BERKSHIRES AND SOUTH INTO EASTERN LITCHFIELD COUNTY...WHERE
DRIZZLE PERSISTS. WE MAY NEED TO EXTEND THE ADVISORIES FOR
PORTIONS OF THESE AREAS...AS COLD AIR MAY REMAIN TOUGH TO
DISLODGE.
STEADIER RAIN SHOULD DEVELOP FROM W TO E DURING THE MID TO LATE
AFTERNOON HOURS. THERE IS SOME POSSIBILITY THAT POCKETS OF
SUBFREEZING TEMPS PERSIST IN PORTIONS OF SE VT AND/OR THE
BERKSHIRES WHEN THIS ARRIVES...SO WILL NEED TO MONITOR CLOSELY.
PREVIOUS DISCUSSION FOLLOWS...
AS OF 6 AM...DRIZZLE IS BEGINNING TO SHOW UP ACROSS THE TRI-STATE
REGION AND MID-HUDSON VALLEY INCLUDING OUR RADAR IN VCP31.
TEMPERATURES VARY BUT THEY DO HOVER AROUND THE FREEZING MARK WHERE
DRIZZLE IS BEING REPORTED. NCEP MODEL SUITE ALONG WITH THE
RUC13/HRRR NOT DOING THAT WELL...HOWEVER...THEY DO SUGGEST THIS
AREA OF DRIZZLE AND SATURATING BOUNDARY LAYER ADVANCES SLOWLY
NORTH THIS MORNING. WET BULB PROFILES ARE STILL BELOW FREEZING SO
WE WILL CONTINUE WITH THE ADVISORY AND REFRESH THE GRIDS AND
HOURLY TEMPS/DEWPTS. PER THE 06Z MOS AND HOURLY LAV/LAMP...MOST
AREAS WILL CLIMB ABOVE FREEZING AROUND THE NOON HOUR.
PREV DISC...
VERY CHALLENGING NEAR TERM FORECAST AS FZDZ HAS NOT
MATERIALIZED AT THIS TIME. PER METARS...THE CIGS REMAIN RATHER
HIGH AND DEWPOINT DEPRESSIONS ARE 5 DEGREES OR GREATER. WE DID
RECEIVE A REPORT OF FLURRIES IN LITCHFIELD COUNTY AND THIS CAN
ALSO BE CONFIRMED WITH SEVERAL METARS ACROSS THE NYC METRO AREA
REPORTING LIGHT SNOW. THIS MAY BE DUE TO THE OCEANIC EFFECT ADDING
ENOUGH NUCLEI TO RESULT IN THOSE OBS OF LIGHT SNOW. THE FORECAST
SOUNDINGS ACROSS OUR REGION STILL SUGGEST THE BOUNDARY LAYER WILL
MOISTEN UP BELOW THE -10C ISOTHERM INCLUDING THE SHEAR PROFILES
FOR SOME DRIZZLE FORMATION. RUC13 FORECAST SOUNDINGS DELAY THE
ONSET OF MOISTURE UNTIL THE 12-15Z TIME FRAME. BY THAT
TIME...TEMPERATURES ARE BEGINNING TO CLIMB TO AT OR ABOVE FREEZING
ALONG AND SOUTH OF I90. THE COLDER AIR IS EXPECTED TO REMAIN IN
PLACE LONGER ACROSS THE DACKS...LAKE GEORGE SARATOGA REGION AND
SOUTHERN VERMONT UNTIL ABOUT THE NOON HOUR. THE ADVISORY LOOKS
GOOD AT THIS TIME WITH NO CHANGES EXPECTED.
POTENT SHORT WAVE TRACKING NORTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY INTO THE GREAT LAKES REGION WILL SEND A COLD FRONT EASTWARD
THIS AFTERNOON. A BAND OF BKN SHOWERS IS EXPECTED AND WE WILL
PLACE CATEGORICAL POPS FOR THE ENTIRE REGION. TIMING OF THIS FRONT
APPEARS TO BE AOA 21Z. AS FOR CONVECTIVE POTENTIAL /IE
THUNDER/...THE SHOWALTER INDEX IS EXPECTED TO DROP TOWARD 0C FOR
PORTIONS OF THE REGION WITH THE BEST UPPER SUPPORT FOR THE WESTERN
MOHAWK VALLEY AND DACKS. WHILE WE WILL NOT INCLUDE THUNDER...WOULD
NOT TOTALLY RULE OUT A RUMBLE OF THUNDER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
WITH FROPA...DRY SLOT QUICKLY APPROACHES THIS EARLY EVENING. SOME
LINGERING UPSLOPE SHOWERS ARE EXPECTED BUT THIS TOO SHOULD
DECREASE THROUGH TONIGHT. SEEMS THE INITIAL COLD ADVECTION WILL
REMAIN WEST OF THE HUDSON RIVER VALLEY WITH TEMPERATURES OVERNIGHT
REMAINING ABOVE FREEZING FOR A GOOD PORTION OF THE REGION. THE
EXCEPTION TO THIS WILL BE FOR PORTIONS OF THE DACKS. LAKE ONTARIO
CONTRIBUTION INCREASES A BIT...ALBEIT MARGINALLY...TO WARRANT
CHANCE POPS FOR RAIN/SNOW SHOWERS TRANSITIONING TO SNOW SHOWER
OVERNIGHT.
DUE TO A RELATIVELY MILDER START TO THE DAY TUESDAY...TEMPERATURES
FOR THE REGION SHOULD ONCE AGAIN CLIMB ABOVE THE FREEZING WITH MID
40S EXPECTED FOR THE MID HUDSON RIVER VALLEY AND NW CT. CYCLONIC
FLOW REMAINS OVER LAKE ONTARIO AND THE DACKS WITH A VEERING WIND
PROFILE TO TAKE WHAT BANDS OF LAKE EFFECT ACTIVITY FURTHER SOUTH.
SECONDARY COLD FRONT IS EXPECTED TO CLEAR THE REGION LATE TUESDAY
AFTERNOON WITH 850MB TEMPS EXPECTED TO PLUNGE BACK BELOW -10C FOR
THE ENTIRE CWA. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A BRIEF
ORGANIZED LAKE EFFECT WITH CLIMBING INVERSION HEIGHTS TUESDAY
EVENING BEFORE FALLING ONCE AGAIN OVERNIGHT. AT THIS POINT...SEEMS
ACCUMULATIONS WILL BE LIMITED AND ISOLATED WITH GENERALLY AROUND 1
INCH. AS UPPER TROUGH SLIDES EAST OF THE REGION...INVERSION
HEIGHTS DROP QUICKLY AS DOES THE DRY AIR ADVECTION ACROSS NY
STATE.
A NARROW SURFACE RIDGE IS EXPECTED ACROSS THE REGION DESPITE
ANOTHER SHORT WAVE MOVING ACROSS THE NORTHERN TIER OF NY AND NEW
ENGLAND. WITH LIMITED MOISTURE...WE WILL KEEP SKIES PTCLOUDY AND
NO MENTION OF PRECIP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE PERIOD WILL START OUT WITH A RIDGE MOVING ACROSS THE REGION AT
THE SURFACE WITH THE FLOW ALOFT FLATTENING. THE MODELS ARE IN FAIRLY
GOOD AGREEMENT WITH THE LONGWAVE PATTERN...HOWEVER THERE ARE
DIFFERENCES IN THE TIMING AND TRACK OF THE SOUTHERN STREAM SYSTEM
WHICH ORIGINATES OVER THE SOUTHERN PLAINS AND HEADS OUR WAY LATE IN
THE WEEK. THERE IS A QUESTION OF HOW MUCH INTERACTION THERE WILL BE
WITH THE NORTHERN STREAM. AT THIS TIME...THIS SYSTEM IS EXPECTED TO
PASS TO SOUTH BRINGING THE CHANCES FOR PRECIPITATION TO THE AREA
THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO RUN ABOVE
NORMAL WITH THE LONGWAVE PATTERN KEEPING THE COLDER AIR TO OUR NORTH
THROUGH THE WORK WEEK. INDICATIONS ARE NORTHERN STREAM ENERGY WILL
DIVE INTO THE NORTHERN PLAINS CAUSING A TROUGH TO DIG OVER THE
EASTERN UNITED STATES OVER THE WEEKEND RETURNING MORE SEASONABLE AIR
TO THE REGION.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
CEILINGS HAVE LOWERED TO MVFR AS THE LOWEST LEVELS OF THE ATMOSPHERE
HAVE FINALLY MOISTEN UP. HAVE HAD REPORTS OF LIGHT DRIZZLE AND
TEMPERATURES ARE AT OR JUST BELOW FREEZING SO WE HAVE FREEZING
DRIZZLE. TEMPERATURES WILL RISE TO ABOVE THE FREEZING MARK BEFORE
THE STEADIER AND HEAVIER PRECIPITATION MOVES IN THIS AFTERNOON.
WIDESPREAD IFR CONDITIONS WILL DEVELOP. THE STEADY PRECIPITATION
WILL MOVE OFF TO THE EAST DURING THE EVENING...HOWEVER IFR
CONDITIONS ARE EXPECTED TO LINGER INTO THE EARLY MORNING HOURS. AN
IMPROVEMENT TO MVFR IS EXPECTED BEFORE SUNRISE WITH VFR DEVELOPING
AT KPOU.
OUTLOOK...
MON NIGHT...MVFR/IFR...IMPROVING TO MVFR/VFR. RAIN TAPERING OFF TO
SCATTERED SHOWERS.
TUE-WED...VFR. NO SIG WX.
THU...MAINLY VFR. CHC -RA/-SN BY LATE IN THE AFTERNOON.
THU NIGHT-FRI..VFR/MVFR. CHC -SHSN/-SHRA.
&&
.HYDROLOGY...
A STORM SYSTEM WILL BRING MIXED PRECIPITATION CHANGING TO RAIN
TODAY. A QUICK SHOT OF MODERATE TO HEAVY RAIN IS POSSIBLE THIS
AFTERNOON WITH A COLD FRONT AS QPF VALUES ARE EXPECTED TO BE BETWEEN
ONE QUARTER TO ONE HALF INCH WITH LOCALIZED AMOUNTS AROUND AN INCH
POSSIBLE INTO THE HIGHER TERRAIN OF THE CATSKILLS...SOUTHERN VERMONT
AND BERKSHIRES.
WE MEASURED THE GROUND FROZEN TO A DEPTH OF 14 INCHES HERE AT THE
OFFICE ON SUNDAY. SOME LOCALIZED POOR DRAINAGE...URBAN AND SMALL
STREAM FLOODING MAY BE POSSIBLE LATER MONDAY DUE TO ENHANCED RUNOFF
FROM RAIN AND MELT ON FROZEN GROUND.
SOME SIGNIFICANT RISES ON MAIN STEM RIVERS ARE POSSIBLE MONDAY INTO
TUESDAY...BUT LARGER RIVER FLOODING IS NOT EXPECTED AT THIS TIME.
RISES WOULD BE ENOUGH TO BREAK UP WHAT RIVER ICE IS IN PLACE BUT ICE
IS NOT THICK ENOUGH TO CAUSE SIGNIFICANT ICE JAM PROBLEMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY UNTIL 2 PM EST TODAY FOR CTZ001-013.
NY...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NYZ033-041>043-082>084.
MA...FREEZING RAIN ADVISORY UNTIL 2 PM EST TODAY FOR MAZ001-025.
VT...FREEZING RAIN ADVISORY UNTIL 2 PM EST TODAY FOR VTZ013>015.
&&
$$
SYNOPSIS...GJM/KL/BGM
NEAR TERM...GJM/KL/BGM
SHORT TERM...BGM
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...SND/BGM
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1104 AM EST MON JAN 23 2012
.SYNOPSIS...
THE SURFACE WEDGE WILL REMAIN ACROSS THE REGION THIS AFTERNOON. A
WEAK FRONT WILL SLOWLY MOVE ACROSS THE REGION TONIGHT AND TUESDAY
MORNING. FAIR WEATHER EXPECTED TUESDAY INTO WEDNESDAY...THEN
RETURNING MOISTURE AND THE APPROACH OF ANOTHER WEATHER SYSTEM WILL
PROVIDE A CHANCE OF PRECIPITATION LATE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DENSE FOG DEVELOPING ACROSS THE CENTRAL AND SOUTH MIDLANDS/CSRA.
WILL ISSUE DENSE FOG ADVISORY UNTIL 300 PM.
LATEST RUC MODEL SUGGEST WEDGE WILL NOT BREAK DOWN THIS
AFTERNOON...MODELS USUALLY BREAK WEDGE TOO QUICKLY...SO WILL LOWER
MAXIMUM TEMPERATURES ABOUT 10 DEGREES.
AS ISENTROPIC LIFT CONTINUES WITH STRONG LOW LEVEL SOUTH FLOW...RAIN
SPREADING IN FROM NORTH CENTRAL GEORGIA...MAINLY ADVECTING INTO
WESTERN MIDLANDS AND CSRA. INCREASED POPS IN THOSE AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE COLD FRONT WILL BE SLOW TO PASS THROUGH THE REGION TONIGHT.
HOWEVER IT APPEARS MOISTURE WILL BE LIMITED...AND MUCH OF THE
UPPER ENERGY WILL HAVE PASSED NORTH OF THE REGION. HAVE ELECTED TO
GO WITH A DRY FORECAST TONIGHT. DID PUT MENTION OF FOG IN FOR NOW.
THE FRONT WILL STALL OUT SOUTH OF THE FORECAST AREA TUESDAY AND
TUESDAY NIGHT. DRY WEATHER EXPECTED THROUGH THAT PERIOD. EVEN
THOUGH THE FRONT WILL BE SOUTH...MORE SUNSHINE ON TUESDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE 60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
LITTLE TO NO CHANGES WERE MADE IN THE LONG TERM. PREVIOUS
DISCUSSION FOLLOWS. GFS/ECMWF CLOSE OFF UPPER LOW AND MOVE IT
SLOWLY EAST ACROSS TEXAS WED/THU. MEANWHILE SURFACE HIGH CENTER
RIDES BY TO OUR NORTH...AND WEAK FRONT LIFTS SLOWLY BACK NORTH
ACROSS OUR REGION. THIS COULD PROVIDE SLIGHT CHANCE POPS...WITH
WEAK ISENTROPIC LIFT BY THURSDAY. BOTH GFS/ECMWF OPEN THE UPPER
LOW AND SHIFT IT EAST ACROSS OUR REGION...BUT DIFFERENCE IN
SOLUTIONS REGARDS TIMING. ECMWF RUN OPENS IT UP EARLIER THAN GFS.
WILL INDICATE HIGH END CHANCE POPS THU NT THRU FRI NT. HIGH
PRESSURE TO BUILD IN BEHIND FRONT LATE IN THE FORECAST PERIOD.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
COLD AIR DAMMING PERSISTS ACROSS THE REGION WITH IFR CIGS/VSBYS
EARLY THIS MORNING UNTIL AROUND 14Z-15Z THIS MORNING AS MOISTURE
FLUX AND INCREASE ISENTROPIC LIFT OVER REGION PRODUCING EITHER
DRIZZLE OR PATCHY LIGHT RAIN ALONG WITH AREAS OF FOG.
WARM FRONT IS EXPECTED TO APPROACH AND BUT REMAIN SOUTH OF THE
AREA THROUGH MOST OF THE AFTERNOON. 17Z- 18Z SCATTERED SHOWERS.
CIGS IFR AND MAY BE MVFR BY LATER THIS AFTERNOON CONTINUING INTO
THE EVENING HOURS. ALSO...WITH INCREASING LOW LEVEL WINDS
SOUTHWEST AROUND 30 KNOTS AT 1-2 KFT WITH WARM FRONT LATER THIS
AFTERNOON MAY LEAD TO LOW LEVEL WIND SHEAR MONDAY AFTERNOON AS THE
WEDGE BEGINS TO BREAK DOWN. ISOLD STORMS MAY BE POSSIBLE DURING
THE AFTERNOON AS WELL BUT WILL JUST USE VCSH IN THE TAFS FOR NOW
GIVEN CURRENT UNCERTAINTIES. CIGS RISE TO AROUND 4 KFT BY AROUND
01Z TUESDAY AS WARM AIR ADVECTION AHEAD OF THE COLD FRONT
INCREASES. AFTER FROPA THIS EVENING...WITH SW FLOW ALOFT...MVFR-
IFR CIGS/VSBYS POSSIBLE UNTIL THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...CEILINGS/VISIBILITIES BECOMING VFR
TUESDAY MORNING. WIDESPREAD IFR CONDITION MAY OCCUR WEDNESDAY NIGHT
THROUGH THURSDAY ASSOCIATED WITH ANOTHER FRONTAL SYSTEM.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR SCZ018-
020-025>028-030-031-035>038-041.
GA...DENSE FOG ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR GAZ040-
063>065-077.
&&
$$
SYNOPSIS...77
NEAR TERM...77
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
519 PM EST MON JAN 23 2012
.SYNOPSIS...
RAIN SHOWERS WILL END THIS EVENING, WITH THE PASSAGE OF A STRONG
COLD FRONT. GUSTY WINDS WILL SUBSIDE LATER TONIGHT. MIDWEST HIGH
PRESSURE WILL FOLLOW WITH DRY, CHILLY CONDITIONS TUESDAY AND WEDNESDAY.
A COLD FRONT COMING EAST FROM THE ROCKIES WILL BRING A MIX OF RAIN
AND SNOW THURSDAY, AND COLDER TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
USED RECENT SURFACE AND RADAR DATA, COUPLED WITH HRRR MODEL OUTPUT
TO ADJUST TIMING OF COLD FRONTAL PASSAGE, AND ITS ASSOCIATED
BANDS OF SHOWERS, AND WIND GUST VALUES.
ONCE THE FRONT PASSES...TEMPERATURES WILL FALL QUICKLY
TONIGHT, AS ADJUSTED USING RECENT GFS LAMP AND HRRR MODEL OUTPUT.
BY LATE TONIGHT, ONLY REMAINING SHOWERS WILL ISOLATED ACROSS THE
I-80 CORRIDOR AND MOUNTAINS. INDICATED THESE CAN BE SNOW SHOWERS,
BUT AN INVERSION ALOFT MAY PRECLUDE ICE NUCLEATION.
HIGH PRESSURE WILL BEGIN TO MOVE IN FROM THE SOUTHWEST ON
TUESDAY...WHICH WILL KEEP WINDS OUT OF THE WEST-SOUTHWEST. HAVE GONE
WITH A SLOW DECREASING TREND FOR CLOUDS DURING THE DAY...SINCE
MODELS SEEM TO BE CLEARING CONDITIONS OUT TOO QUICKLY. HIGHS WILL BE
BETWEEN 10-20 DEGREES COLDER TOMORROW...ALTHOUGH THOSE VALUES WILL
BE NEAR CLIMATOLOGY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE WILL BE OVERHEAD TUESDAY NIGHT...BRINGING CALM AND
CLEAR CONDITIONS.
CLOUDS WILL BE ON THE INCREASE WEDNESDAY AS LOW PRESSURE DEVELOPS
OVER THE GULF COAST. 12Z GFS IS THE FAST OUTLIER WITH BRINGING IN
PRECIPITATION BY WEDNESDAY AFTERNOON...AND WILL STICK WITH MORE
CONSENSUS...SLOWER SOLUTIONS.
MODELS ARE IN GOOD AGREEMENT THAT MODEL PROFILES WILL BE NEAR
FREEZING MOST OF WEDNESDAY NIGHT...BUT THERE IS THE POTENTIAL FOR
SOME FREEZING PRECIPITATION OVERNIGHT. HOWEVER...NOT ENOUGH
CONFIDENCE TO GO WITH ANYTHING OTHER THAN RAIN/SNOW IN THE
FORECAST FOR NOW.
PRECIPITATION WILL SPREAD FROM SOUTH TO NORTH ON THURSDAY...AND
WILL GENERALLY GO WITH HIGH CHANCE POPS DURING THE DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CONCURRING WITH HPC GUIDANCE, MADE FORECAST WITH MORE PREFERENCE TO
ECMWF MODEL OUTPUT. HENCE EXPECT MIXED PRECIPITATION THURSDAY NIGHT
TO BECOME SHOWERY FRIDAY AS TEXAS-BRED LOW PRESSURE SYSTEM PHASES
WITH PLAINS-BRED COLD FRONT IN THEIR EASTWARD PASSAGE THROUGH
THROUGH THE UPPER OHIO VALLEY THURSDAY NIGHT.
WITH THE UPPER-LEVEL JETSTREAM, DEVELOPING A COLD TROUGH OVER
CENTRAL CANADA THIS WEEKEND, THE NORTHERN JETSTREAM BRANCH WILL
PROMOTE ADDITIONAL PLAINS-BRED COLD FRONTS TO MOVE EASTWARD
THROUGH THE UPPER OHIO VALLEY SATURDAY AND MONDAY.
REGARDING TEMPERATURE DETAILS, PER RECENT HPC GUIDANCE AND NAEFS
MODEL OUTPUT, FORECASTED A COOL DOWN IN TEMPERATURES IN THE WAKE OF
THURSDAY NIGHT`S SYSTEMS, WITH VALUES PERHAPS AS COLD AS 5 TO 10
DEGREES COLDER THAN NORMAL IN THE WAKE OF SATURDAY`S COLD FRONTAL
PASSAGE. HENCE WHATEVER PRECIPITATION COMES SUNDAY INTO EARLY
MONDAY, IT WILL BE SHOWERS OF SNOW RATHER THAN RAIN.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
RECENT RADAR AND SURFACE DATA, COUPLED WITH HRRR MODEL OUTPUT,
SHOW TWO NARROW COLD FRONTAL BAND OF MVFR SHOWERS WILL CONTINUE TO
MOVE EASTWARD THROUGH THE UPPER OHIO VALLEY THROUGH 00Z. SURFACE
WIND GUSTS CAN REACH 35-40 KTS. CONVECTION WILL BE GENERALLY TOO
SHALLOW FOR CLOUD TOPS TO REACH TEMPERATURES OF -20C. SO NO MORE
THUNDER FORECASTED.
ENSUING POSTFRONTAL COOL DOWN, BEST DEPICTED BY NAM MODEL
PROFILES, WILL PROMOTE A WELL-MIXED SURFACE LAYER TONIGHT, WHICH
WILL MAINTAIN MVFR STRATOCUMULUS AND SURFACE WIND GUSTS TO 25-30
KTS. A DEVELOPING CAPPING TEMPERATURE INVERSION NEAR 5 KFT AGL
SHOULD RESTRICT INSTABILITY SHOWER DEVELOPMENT. BY DAYTIME TUESDAY,
SURFACE WINDS SHOULD EASE TO 15-20 KTS AND STRATOCUMULUS CEILINGS
COULD LIFT TO VFR LEVELS BY AFTERNOON.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
VFR TUESDAY NIGHT AND WEDNESDAY. MIXED PRECIPITATION AND RESTRICTIONS
POSSIBLE THURSDAY AND FRIDAY, AS LOW PRESSURE MOVES NORTHEAST FROM
TEXAS. AN ADDITIONAL PERIOD OF RESTRICTIONS IS POSSIBLE WITH A COLD
FRONTAL BAND OF SHOWERS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
339 PM EST MON JAN 23 2012
.SYNOPSIS...
AS A COLD FRONT MOVES THROUGH THE REGION TONIGHT...EXPECT ONE LAST
ROUND OF SHOWERS ALONG WITH GUSTY WINDS. CONDITIONS SHOULD THEN BE
GENERALLY DRY UNTIL WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TUESDAY/...
COLD FRONT WILL MOVE EAST DURING THE EVENING HOURS...WHICH AS OF MID
AFTERNOON IS ACROSS EASTERN OHIO. MANY LOCATIONS ARE EXPERIENCING
GUSTS UP TO 40-45 MPH IN SHOWERS AS THE COLD FRONT MOVES THROUGH.
CONSIDERING WIND GUSTS ARE ONLY IN CONVECTIVE SHOWERS...STRONG
WINDS WILL BE HANDLED BY SEVERE THUNDERSTORM WARNINGS AS
NECESSARY. ONCE THE FRONT PASSES...TEMPERATURES WILL FALL QUICKLY
TONIGHT...EVEN THOUGH CLOUD COVER WILL REMAIN ACROSS THE AREA.
WILL CONTINUE TO GO SLIGHTLY BELOW MODEL GUIDANCE FOR
TEMPERATURES...ALTHOUGH MANY LOCATIONS HAVE SEEN A RAPID DECREASE
IN SNOW COVER TODAY.
HIGH PRESSURE WILL BEGIN TO MOVE IN FROM THE SOUTHWEST ON
TUESDAY...WHICH WILL KEEP WINDS OUT OF THE WEST-SOUTHWEST. HAVE GONE
WITH A SLOW DECREASING TREND FOR CLOUDS DURING THE DAY...SINCE
MODELS SEEM TO BE CLEARING CONDITIONS OUT TOO QUICKLY. HIGHS WILL BE
BETWEEN 10-20 DEGREES COLDER TOMORROW...ALTHOUGH THOSE VALUES WILL
BE NEAR CLIMATOLOGY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE WILL BE OVERHEAD TUESDAY NIGHT...BRINGING CALM AND
CLEAR CONDITIONS. CLOUDS WILL BE ON THE INCREASE WEDNESDAY AS LOW
PRESSURE DEVELOPS OVER THE GULF COAST. 12Z GFS IS THE FAST OUTLIER
WITH BRINGING IN PRECIPITATION BY WEDNESDAY AFTERNOON...AND WILL
STICK WITH MORE CONSENSUS...SLOWER SOLUTIONS. MODELS ARE IN GOOD
AGREEMENT THAT MODEL PROFILES WILL BE NEAR FREEZING MOST OF
WEDNESDAY NIGHT...BUT THERE IS THE POTENTIAL FOR SOME FREEZING
PRECIPITATION OVERNIGHT. HOWEVER...NOT ENOUGH CONFIDENCE TO GO WITH
ANYTHING OTHER THAN RAIN/SNOW IN THE FORECAST FOR NOW. PRECIPITATION
WILL SPREAD FROM SOUTH TO NORTH ON THURSDAY...AND WILL GENERALLY GO
WITH HIGH CHANCE POPS DURING THE DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CONCURRING WITH HPC GUIDANCE, MADE FORECAST WITH MORE PREFERENCE TO
ECMWF MODEL OUTPUT. HENCE EXPECT MIXED PRECIPITATION THURSDAY NIGHT
TO BECOME SHOWERY FRIDAY AS TEXAS-BRED LOW PRESSURE SYSTEM PHASES
WITH PLAINS-BRED COLD FRONT IN THEIR EASTWARD PASSAGE THROUGH
THROUGH THE UPPER OHIO VALLEY THURSDAY NIGHT.
WITH THE UPPER-LEVEL JETSTREAM, DEVELOPING A COLD TROUGH OVER
CENTRAL CANADA THIS WEEKEND, THE NORTHERN JETSTREAM BRANCH WILL
PROMOTE ADDITIONAL PLAINS-BRED COLD FRONTS TO MOVE EASTWARD
THROUGH THE UPPER OHIO VALLEY SATURDAY AND MONDAY.
REGARDING TEMPERATURE DETAILS, PER RECENT HPC GUIDANCE AND NAEFS
MODEL OUTPUT, FORECASTED A COOL DOWN IN TEMPERATURES IN THE WAKE OF
THURSDAY NIGHT`S SYSTEMS, WITH VALUES PERHAPS AS COLD AS 5 TO 10
DEGREES COLDER THAN NORMAL IN THE WAKE OF SATURDAY`S COLD FRONTAL
PASSAGE. HENCE WHATEVER PRECIPITATION COMES SUNDAY INTO EARLY
MONDAY, IT WILL BE SHOWERS OF SNOW RATHER THAN RAIN.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
RECENT SURFACE AND SATELLITE DATA SHOW STRATOCUMULUS HAS LIFTED TO
MVFR LEVELS ACROSS THE I-80 CORRIDOR, WHILE PREFRONTAL SCATTERED TO
BROKEN VFR STRATOCUMULUS HAVE SHIFTED EASTWARD FROM EASTERN OHIO
INTO WESTERN PENNSYLVANIA AND NORTHERN WEST VIRGINIA. DESPITE THE
SURFACE LAYER REMAINING RATHER STABLE, SURFACE WIND GUSTS CAN REACH
25-30 KTS.
RECENT RADAR AND SURFACE DATA, COUPLED WITH HRRR MODEL OUTPUT, SHOW
A NARROW COLD FRONTAL BAND OF MVFR SHOWERS WILL CONTINUE TO MOVE
EASTWARD THROUGH THE UPPER OHIO VALLEY THROUGH 00Z. SURFACE WIND
GUSTS CAN REACH 35-40 KTS. CONVECTION WILL BE TOO SHALLOW FOR CLOUD
TOPS TO REACH TEMPERATURES OF -20C. SO NO THUNDER FORECASTED.
ENSUING POSTFRONTAL COOL DOWN, BEST DEPICTED BY NAM MODEL
PROFILES, WILL PROMOTE A WELL-MIXED SURFACE LAYER TONIGHT, WHICH
WILL MAINTAIN MVFR STRATOCUMULUS AND SURFACE WIND GUSTS TO 25-30
KTS. A DEVELOPING CAPPING TEMPERATURE INVERSION NEAR 5 KFT AGL
SHOULD RESTRICT INSTABILITY SHOWER DEVELOPMENT. BY DAYTIME TUESDAY,
SURFACE WINDS SHOULD EASE TO 15-20 KTS AND STRATOCUMULUS CEILINGS
COULD LIFT TO VFR LEVELS BY AFTERNOON.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
VFR TUESDAY NIGHT AND WEDNESDAY. MIXED PRECIPITATION AND RESTRICTIONS
POSSIBLE THURSDAY AND FRIDAY, AS LOW PRESSURE MOVES NORTHEAST FROM
TEXAS. AN ADDITIONAL PERIOD OF RESTRICTIONS IS POSSIBLE WITH A COLD
FRONTAL BAND OF SHOWERS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
101 PM EST MON JAN 23 2012
.SYNOPSIS...
EASTBOUND COLD FRONT WILL BRING PERIODS OF RAIN SHOWERS AND GUSTY
WINDS THIS AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF EARLY AFTERNOON...RAIN HAS MOVED EAST OF THE AREA...WITH A
SMALL AREA OF CLEARING BEHIND THE RAIN AND AHEAD OF ADVANCING COLD
FRONT CURRENTLY IN WESTERN OHIO.
A LINE OF SHALLOW CONVECTION IS DEVELOPING ALONG THE COLD FRONT.
THIS WILL BRING ANOTHER ROUND OF SHOWERS...THIS TIME BRINGING SOME
GUSTY WINDS. MANY OBSERVING SITES ARE GUSTING TO 30-40 MPH AS THE
FRONT MOVES THROUGH. WILL KEEP AN EYE ON THE LINE OF SHOWERS AS IT
APPROACHES THE AREA. THIS LINE SHOULD CLEAR THE AREA BY EARLY
EVENING. WARM AIR IS SURGING NORTH OF THE FRONT...ESPECIALLY WHERE
SKIES HAVE CLEARED.
OVERCAST CONDITIONS REMAIN ALONG I-80 WITH TEMPS CURRENTLY IN THE
MID 30S...BUT MORGANTOWN WAS 59 DEGREES AT NOON. WHEN THE COLD
FRONT COMES THROUGH...TEMPERATURES WILL BE NOTICEABLY COLDER.
AS WINDS BECOME WESTERLY BEHIND THE FRONT...SOME ISOLATED LAKE
ENHANCED SHOWERS WILL REMAIN NEAR INTERSTATE 80 AND ALONG THE
RIDGES. COLDER TEMPERATURES WILL ALLOW FOR RAIN TO CHANGE OVER TO
SNOW...WITH VERY LIGHT ACCUMULATIONS POSSIBLE.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
AS LOW PRESSURE HEADS EAST TO NEW ENGLAND TUESDAY WEAK SURFACE
RIDGE WILL BUILD INTO REGION INTO WEDNESDAY WITH SEASONABLE
TEMPERATURES AND GENERAL DRY CONDITIONS. MODELS NOW IN MORE
AGREEMENT FOR A FASTER ARRIVAL OF DEEP MOISTURE AHEAD OF A
SHORTWAVE IN THE NORTHERN BRANCH AND A CLOSED LOW ACROSS TEXAS.
RAISED POPS AND WENT WITH A MIX OF RAIN AND SNOW FOR WEDNESDAY
NIGHT INTO THURSDAY. THIS SYSTEM COULD GET MESSY BUT AMOUNT OF
COLD AIR AVAILABLE IN DOUBT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
LOW PRESSURE WILL MOVE TO THE EAST COAST THURSDAY NIGHT INTO FRIDAY
WITH CHANCE POPS FOR MIXED RAIN AND SNOW DIMINISHING DURING THE
DAY FRIDAY. ANOTHER FAST MOVING SYSTEM WILL ARRIVE SATURDAY FOR A
CHANCE OF SHOWERS WITH COLDER TEMPERATURES AND POSSIBLE SNOW
SHOWERS SUNDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
RECENT SURFACE AND SATELLITE DATA SHOW STRATUS LINGERING ACROSS
THE I-80 CORRIDOR, WHILE PREFRONTAL SCATTERED TO BROKEN VFR
STRATOCUMULUS HAVE SHIFTED EASTWARD FROM EASTERN OHIO INTO WESTERN
PENNSYLVANIA AND NORTHERN WEST VIRGINIA. DESPITE THE SURFACE LAYER
REMAINING RATHER STABLE, SURFACE WIND GUSTS CAN REACH 25-30 KTS.
RECENT RADAR AND SURFACE DATA, COUPLED WITH HRRR MODEL OUTPUT,
SHOW A NARROW COLD FRONTAL BAND OF MVFR SHOWERS WILL MOVE EASTWARD
THROUGH THE UPPER OHIO VALLEY 19Z-24Z. SURFACE WIND GUSTS CAN
REACH 35-40 KTS. CONVECTION WILL BE TOO SHALLOW FOR CLOUD TOPS TO
REACH TEMPERATURES OF -20C. SO NO THUNDER FORECASTED.
ENSUING POSTFRONTAL COOL DOWN, BEST DEPICTED BY NAM MODEL
PROFILES, WILL PROMOTE A WELL-MIXED SURFACE LAYER TONIGHT, WHICH
WILL MAINTAIN MVFR STRATOCUMULUS AND SURFACE WIND GUSTS TO 25-30
KTS. A DEVELOPING CAPPING TEMPERATURE INVERSION NEAR 5 KFT AGL
SHOULD RESTRICT INSTABILITY SHOWER DEVELOPMENT. BY DAYTIME TUESDAY,
SURFACE WINDS SHOULD EASE TO 15-20 KTS AND STRATOCUMULUS CEILINGS
COULD LIFT TO VFR LEVELS BY AFTERNOON.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...
VFR TUESDAY NIGHT AND WEDNESDAY. MIXED PRECIPITATION AND RESTRICTIONS
POSSIBLE THURSDAY AND FRIDAY, AS LOW PRESSURE MOVES NORTHEAST FROM
TEXAS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
422 PM EST MON JAN 23 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS WESTERN NEW YORK TONIGHT BRINGING
SHOWERS ALONG WITH STRONG GUSTY WINDS. LAKE EFFECT EFFECT SHOWERS
DEVELOPING IN THE WAKE OF THE FRONT ON TUESDAY WILL BRING LIGHT SNOW
ACCUMULATIONS TO THE NORTH COUNTRY WITH LITTLE OR NO ACCUMULATION
EAST OF LAKE ERIE. HIGH PRESSURE WILL BRING A BRIEF RETURN TO QUIET
WEATHER ON WEDNESDAY BEFORE THE NEXT SYSTEM BRINGS ANOTHER CHANCE OF
PRECIPITATION THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
THE PRIMARY WEATHER MAKER FOR WESTERN NEW YORK WILL BE A MATURE LOW
PRESSURE SYSTEM CURRENTLY CENTERED OVER THE EASTERN END OF
MICHIGAN/S UPPER PENINSULA. THE LOW WILL LIFT INTO WESTERN QUEBEC
TONIGHT AS WHILE COLD AIR WRAPPING INTO THE LOW WILL SWEEP A STRONG
COLD FRONT ACROSS WESTERN NEW YORK MAKING STRONG WINDS AND FALLING
TEMPERATURES THE MAIN FORECAST CONCERNS FOR TONIGHT.
AS THE AFOREMENTIONED COLD FRONT MOVES ACROSS THE REGION
TONIGHT...EXPECT STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE
CREATING GUSTY WINDS TONIGHT ACROSS WESTERN NEW YORK. LATEST MODEL
GUIDANCE SUGGESTS THAT THE CORE OF THE SOUTHWESTERLY LOW LEVEL JET
WILL STAY ACROSS AND TO THE WEST OF THE NIAGARA
FRONTIER...SUGGESTING THAT ADVISORY LEVEL WINDS WITH GUSTS TO AROUND
50 MPH WILL BE LIMITED TO THE WESTERNMOST COUNTIES IN NEW YORK. THE
JET LIFTS NORTH ACROSS LAKE ONTARIO OVERNIGHT SPARING THE NORTH
COUNTRY FROM THE STRONGEST WINDS. EXPECT TEMPERATURES TO DROP
MARKEDLY BEHIND THE FRONT WITH LOWS BOTTOMING OUT IN THE UPPER 20S
TO NEAR 30 ACROSS FAR WESTERN NEW YORK AND THE SOUTHERN TIER. THE
COLD AIR WILL TAKE A LITTLE LONGER TO REACH AREAS EAST OF LAKE
ONTARIO WHERE TEMPERATURES SHOULD REMAIN JUST ABOVE FREEZING.
REGARDING THE PRECIPITATION FORECAST FOR TONIGHT...CURRENT RADAR OBS
INDICATE ANOTHER BAND OF SHOWERS WITH ISOLATED THUNDER OVER
WESTERN OHIO ASSOCIATED WITH FRONTAL FORCING ALONG THE COLD
FRONTAL BOUNDARY WITH ADDITIONAL ENHANCEMENT FROM INCREASED
INSOLATION/DIABATIC HEATING DUE TO A DRY SLOT MOVING ACROSS THAT
REGION. HRRR MODEL CURRENTLY HAS A GOOD HANDLE ON THE SHOWER
ACTIVITY...BRINGING IT INTO THE NIAGARA FRONTIER BY EARLY EVENING
AND QUICKLY FALLING APART BY THE TIME IT REACHES THE GENESEE
VALLEY AS INSTABILITY AND SYNOPTIC FORCING WEAKENS. WILL CARRY
LIKELY TO CATEGORICAL POPS FOR THE WESTERN COUNTIES WITH A SLIGHT
CHANCE OF THUNDER THIS EVENING TRANSITIONING TO CHANCE POPS FOR
THE EASTERN HALF OF THE FORECAST AREA.
COLD AIR FILTERING IN BEHIND THE COLD FRONT NECESSITATES A
DISCUSSION OF LAKE EFFECT POTENTIAL ON TUESDAY. WHILE 850MB TEMPS
GET NOMINALLY COLD ENOUGH FOR LAKE EFFECT...AROUND -10C TO -12C
ACROSS LAKE ERIE WITH A FAVORABLE WEST-SOUTHWEST WIND AND LOW
SHEAR...THE PRESENCE OF SUBSTANTIAL DRY AIR IN THE DENDRITIC GROWTH
ZONE AND AN INVERSION LEVEL RUNNING AT 5KFT OR LOWER IS NOT
IMPRESSIVE. THE REGIONAL GEM MODEL KEEPS THE DEEPER MOISTURE A
LITTLE FARTHER SOUTH...RESULTING IN A SLIGHTLY MORE FAVORABLE
PROFILE FOR SNOW. GIVEN THIS UNCERTAINTY...WILL KEEP POPS LIMITED TO
CHANCE EAST OF LAKE ERIE AND KEEP WEATHER LIMITED TO FLURRIES. EAST
OF LAKE ONTARIO...LONGER FETCH OFF OF THE LAKE AND SLIGHTLY COLDER
AIR IN THE LOWER LEVELS MAY RAISE THE INVERSION JUST ENOUGH TO
GENERATE SOME LIGHT SNOW SHOWERS...MAINLY ACROSS JEFFERSON AND LEWIS
COUNTIES...THOUGH ACCUMULATIONS WILL GENERALLY RUN IN THE
NEIGHBORHOOD OF 1-3 INCHES AT BEST.
PLENTY OF COLD AIR AND LAKE INDUCED CLOUD COVER IN PLACE WILL MAKE
FOR A TYPICAL DAY...FOR LATE JANUARY...WITH HIGHS RANGING FROM THE
UPPER 20S TO LOWER 30S ACROSS THE FORECAST AREA.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A PROGRESSIVE PATTERN WILL BE IN PLACE ACROSS NORTH AMERICA DURING
THIS PERIOD AS THE BROAD POLAR VORTEX THAT HAS BEEN IN PLACE OVER
CANADA WILL RETROGRADE TO ALASKA. THIS WILL KEEP A STRONG ZONAL JET
OVER THE GULF OF ALASKA AND PACIFIC NORTHWEST...WHICH WILL RESULT IN
A CONTINUAL FEED OF PACIFIC MODIFIED AIR OVER THE LOWER 48. OUR
TEMPERATURES WILL AVERAGE ABOVE NORMAL AS A RESULT...WITH LITTLE IN
THE WAY OF SIGNIFICANT WEATHER. THE DETAILS...
A SECONDARY COLD FRONT WILL DROP ACROSS THE LOWER GREAT LAKES ON
TUESDAY NIGHT...AND WHILE A VERY SHORT LIVED POCKET OF -10C H85 AIR
WILL SUPPORT SOME LAKE EFFECT EAST OF LK ONTARIO...SNOWFALL AMOUNTS
WILL NOT BE SIGNIFICANT. LAKE INDUCED CONVECTION EARLY ON SHOULD
DISINTEGRATE AS PACIFIC BASED AIR MOVES IN AND PUMPS H85`S TO -4C.
OTHERWISE...ANY NUISANCE SNOW SHOWERS ASSOCIATED WITH THE FRONTAL
PASSAGE WILL QUICKLY GIVE WAY TO CLEARING SKIES AS HIGH PRESSURE
WILL BUILD ACROSS ALL OF THE GREAT LAKES REGION.
WEDNESDAY SHOULD BE A FAIRLY NICE DAY ACROSS THE REGION AS A LARGE
AREA OF HIGH PRESSURE WILL DRIFT ACROSS PENNSYLVANIA. WILL BUMP MAX
TEMPS UP A BIT FROM CONTINUITY...AS H85`S ARE EXPECTED TO MODERATE
TO AROUND ZERO/-2C. THIS SHOULD SUPPORT AFTERNOON READINGS IN THE
MID 30S ACROSS THE LOWER ELEVATIONS...WHILE THE NORTH COUNTRY WILL
EXPERIENCE HIGHS CLOSER TO THE SEASONAL NORM IN THE UPPER 20S.
A WEAKLY DIVERGENT FLOW WILL ACCOMPANY A JET STREAK ACROSS THE LOWER
GREAT LAKES ON WEDNESDAY NIGHT...AND THIS WILL LIKELY LEAD TO AN
INCREASE IN CLOUD COVER. GIVEN THE DEARTH OF MOISTURE AND OVERALL
SYNOPTIC LIFT...WILL ONLY CARRY SLGT CHC POPS.
A POTENT SHORTWAVE WILL THEN DIG ACROSS THE UPPER MISSISSIPPI VALLEY
ON THURSDAY...AND THIS WILL HELP TO AMPLIFY AN ALREADY BULGING
SHORTWAVE RIDGE OVER OUR FORECAST AREA. WHILE THIS WILL PROMOTE FAIR
WEATHER ACROSS OUR REGION FOR THE BULK OF THE DAY...WE WILL
EXPERIENCE AN INCREASE IN CLOUD COVER AS LOW LEVEL MOISTURE WILL
POOL IN ADVANCE OF THE NEXT FRONTAL SYSTEM. THERE COULD EVEN BE A
COUPLE LIGHT RAIN SHOWERS IN THE AFTERNOON OVER THE FAR WESTERN
COUNTIES.
FOR THURSDAY NIGHT...OUR REGION WILL FIND ITSELF STRADDLED BY A PAIR
OF STORM SYSTEMS. THE AFOREMENTIONED UPPER MISSISSIPPI VALLEY SHORT
WAVE WILL TRACK ACROSS SOUTHERN ONTARIO WHILE A SFC LOW GENERATED IN
THE SOUTHERN BRANCH IS EXPECTED TO MAKE ITS WAY ACROSS THE
APPALACHIANS TO VIRGINIA. A PACIFIC BASED COLD FRONT STRETCHING
BETWEEN THE TWO WILL CROSS OUR FORECAST AREA DURING THE COURSE OF
THE NIGHT. SINCE FORCING BETWEEN THE TWO SYSTEMS SHOULD NOT BE VERY
STRONG...LIGHT LOW QPF SHOWERY PCPN COULD PROVE TO BE PROBLEMATIC AS
A WINTRY MIX WILL BE POSSIBLE.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
WHILE TEMPERATURES WILL AVERAGE ABOVE NORMAL FOR THE WEEKEND...IT
LOOKS AS IF WE WILL GET A SHOT OF SEASONABLY COLD AIR BY THE END OF
THIS PERIOD. KEEP IN MIND THAT THIS IS LOOKING OUT TO DAY 7...BUT
THERE IS A SUGGESTION BY THE MEDIUM RANGE PACKAGES THAT A
SIGNIFICANT SHORTWAVE WILL HELP TO AMPLIFY AN ALREADY EXISTING
TROUGH OVER THE EASTERN U.S.
THE ORIGINS OF THIS SHORTWAVE CAN BE SEEN IN WV IMAGERY OVER
NORTHERN SIBERIA. AS THIS IMPRESSIVE FEATURE WEAKENS...ENERGY WILL
BE EJECTED ACROSS THE HIGH ARCTIC TO ALASKA WHERE IT IS FORECAST TO
DISLODGE A CLOSED LOW. THE RESULTING SHORTWAVE WILL THEN DROP `DOWN
THE CHUTE` ACROSS BRITISH COLUMBIA TO THE CENTRAL U.S. AT THE START
OF THIS PERIOD...AND OVER THE NATIONS MID SECTION OVER THE COURSE OF
THE WEEKEND.
THIS WILL DEEPEN AND ENERGIZE THE EASTERN U.S. TROUGH WITH COLDER
AIR SETTLING OVER OUR REGION LATE IN THE WEEKEND AND EARLY NEXT
WEEK. SUCH A PATTERN WOULD ALSO LIKELY SPAWN A COASTAL STORM...BUT
THAT WOULD NOT BE AN ISSUE FOR OUR REGION. NOW...LETS LOOK AT THE
DETAILS ON A MORE LOCAL LEVEL.
SFC BASED RIDGING WILL MOVE ACROSS OUR REGION ON FRIDAY. THIS WILL
CLEAR OUT THE PCPN FROM WEST TO EAST WITH THE ONLY REMAINING MENTION
OF PCPN BEING OVER THE EASTERN LAKE ONTARIO REGION. H85 TEMPS IN THE
VCNTY OF -4C WILL SUPPORT AFTERNOON TEMPS IN THE 30S TO NEAR 40F.
THE RIDGE WILL MOVE EAST ON SATURDAY AS A DIGGING TROUGH WILL BE
FOUND OVER THE MISSISSIPPI VALLEY AND UPPER GREAT LAKES. THE
LOWERING HGTS ACROSS THE GREAT LAKES WILL HELP SOME COLDER AIR TO
SAG ACROSS THE FORECAST AREA WITH WINDS FRESHENING AS A RESULT OF
STRONGER WINDS BELOW H85.
IT WILL BECOME SOMEWHAT UNSETTLED SATURDAY NIGHT AND SUNDAY AS THE
BASE OF THE SHARPENED H5 TROUGH WILL SWING ACROSS THE LOWER GREAT
LAKES. IT WILL BECOME COLDER WITH SCATTERED SNOW SHOWERS AND
CONCENTRATED LAKE SNOWS SOUTHEAST OF THE LAKES.
FINALLY FOR SUNDAY NIGHT AND MONDAY...THE CORE OF THE COOLEST AIR
WILL BE MOVING ACROSS EASTERN CANADA WITH H85 TEMPS GENERALLY IN THE
MINUS TEENS FOR OUR FORECAST AREA. WHILE THIS WOULD PROMOTE SOME
LAKE EFFECT SNOWS...LOW LEVEL RIDGING SHOULD LIMIT ACCUMULATIONS.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
ALL TAF SITES EXCEPT JHW REMAIN AT VFR AS OF 21Z. JHW UNDER MVFR
CIGS AS A LOW LEVEL INVERSION WILL CONTINUE TO KEEP LOW LEVEL
MOISTURE TRAPPED NEAR THE SFC THERE.
SOME CONVECTIVE SHOWERS HAVE RECENTLY DEVELOPED AHEAD OF THE COLD
FRONT OFF TO THE WEST WHERE ISOLATED LIGHTNING HAS BEEN OBSERVED.
THE TAFS HAVE BEEN AMENDED FOR TIMING OF ARRIVAL OF SHOWERS
ASSOCIATED ALONG THE FRONT AND ANY SCT ACTIVITY PREFRONTAL. FRONT
WILL BE PASSING FORECAST AREA IN THE 23Z-02Z TIME FRAME. ADDED CB
TO JHW/BUF/IAG AS AN ISOLATED STROKE OF LIGHTNING IS POSSIBLE WITH
WEAK INSTABILITY ALONG THE FRONT. CIGS WERE LOWERED TO MVFR DURING
FRONTAL SHOWER ACTIVITY AT ALL SITES.
WIND SHEAR STILL REMAINS AN ISSUE INTO AHEAD OF THE FRONT AS MODEL TIME
SECTIONS SHOW LOW LEVEL JET OF 50+ KTS AT 1-2 KFT. WINDS WILL
VEER TO SW WITH COLD ADVECTION OCCURRING BEHIND THE FRONT. THIS
WILL ERODE THE PRESENT INVERSION IN PLACE OVER THE AREA AND HIGHER
WINDS WILL BE ABLE TO MIX DOWN TO THE SURFACE WITH GUSTS TO 40KTS
POSSIBLE DURING THE EVENING POST FRONTAL. CONDITIONS WILL NOT
CHANGE MUCH FOR THE SECOND HALF OF THE TAF PERIOD WITH MVFR CIGS
AND GUSTY SW WINDS EXPECTED.
ANOTHER CONCERN THAT WILL HAVE TO BE WATCHED EARLY TUESDAY IS THE
CHANCE FOR ZDR 09Z-12Z. RECENT NAM MODEL INDICATED SATURATED LOW
LEVELS WITH SUB-FREEZING TEMPS BUT DRY AIR IN THE SNOW GROWTH ZONE
COLD YIELD SOME PATCHY ZDR.
OUTLOOK...
WEDNESDAY...VFR.
THURSDAY AND FRIDAY...MAINLY VFR WITH A CHANCE OF RAIN/SNOW SHOWERS.
SATURDAY...VFR WITH CHANCE FOR SNOW SHOWERS.
&&
.MARINE...
A COLD FRONT WILL SWEEP ACROSS THE LAKES TONIGHT BRINGING FRESH
SOUTHWESTERLIES WITH A FEW GUSTS TO GALE FORCE POSSIBLE ACROSS
EASTERN LAKE ERIE. STRONG WINDS MIXING DOWN TO THE SURFACE MAY BRING
GALES TO THE OPEN WATERS OF WESTERN LAKE ONTARIO OVERNIGHT AS WELL.
SMALL CRAFT ADVISORY LEVEL WESTERLIES WILL REMAIN IN PLACE ACROSS
THE LAKES THROUGH MUCH OF TUESDAY NIGHT BEFORE HIGH PRESSURE BUILDS
ACROSS THE REGION WEDNESDAY...BRINGING A PERIOD OF CALMER WINDS AND
WAVES THAT WILL LAST INTO THURSDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WIND ADVISORY UNTIL 5 AM EST TUESDAY FOR NYZ001-002-010-011-
019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 6 PM EST TUESDAY FOR LEZ020.
GALE WARNING FROM 9 PM THIS EVENING TO 7 AM EST
TUESDAY FOR LOZ062.
SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR
LOZ042>045.
&&
$$
SYNOPSIS...WOOD
NEAR TERM...WOOD
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...SMITH
MARINE...WOOD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
350 PM EST MON JAN 23 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS WESTERN NEW YORK TONIGHT BRINGING
SHOWERS ALONG WITH STRONG GUSTY WINDS. LAKE EFFECT EFFECT SHOWERS
DEVELOPING IN THE WAKE OF THE FRONT ON TUESDAY WILL BRING LIGHT SNOW
ACCUMULATIONS TO THE NORTH COUNTRY WITH LITTLE OR NO ACCUMULATION
EAST OF LAKE ERIE. HIGH PRESSURE WILL BRING A BRIEF RETURN TO QUIET
WEATHER ON WEDNESDAY BEFORE THE NEXT SYSTEM BRINGS ANOTHER CHANCE OF
PRECIPITATION THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
THE PRIMARY WEATHER MAKER FOR WESTERN NEW YORK WILL BE A MATURE LOW
PRESSURE SYSTEM CURRENTLY CENTERED OVER THE EASTERN END OF
MICHIGAN/S UPPER PENINSULA. THE LOW WILL LIFT INTO WESTERN QUEBEC
TONIGHT AS WHILE COLD AIR WRAPPING INTO THE LOW WILL SWEEP A STRONG
COLD FRONT ACROSS WESTERN NEW YORK MAKING STRONG WINDS AND FALLING
TEMPERATURES THE MAIN FORECAST CONCERNS FOR TONIGHT.
AS THE AFOREMENTIONED COLD FRONT MOVES ACROSS THE REGION
TONIGHT...EXPECT STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE
CREATING GUSTY WINDS TONIGHT ACROSS WESTERN NEW YORK. LATEST MODEL
GUIDANCE SUGGESTS THAT THE CORE OF THE SOUTHWESTERLY LOW LEVEL JET
WILL STAY ACROSS AND TO THE WEST OF THE NIAGARA
FRONTIER...SUGGESTING THAT ADVISORY LEVEL WINDS WITH GUSTS TO AROUND
50 MPH WILL BE LIMITED TO THE WESTERNMOST COUNTIES IN NEW YORK. THE
JET LIFTS NORTH ACROSS LAKE ONTARIO OVERNIGHT SPARING THE NORTH
COUNTRY FROM THE STRONGEST WINDS. EXPECT TEMPERATURES TO DROP
MARKEDLY BEHIND THE FRONT WITH LOWS BOTTOMING OUT IN THE UPPER 20S
TO NEAR 30 ACROSS FAR WESTERN NEW YORK AND THE SOUTHERN TIER. THE
COLD AIR WILL TAKE A LITTLE LONGER TO REACH AREAS EAST OF LAKE
ONTARIO WHERE TEMPERATURES SHOULD REMAIN JUST ABOVE FREEZING.
REGARDING THE PRECIPITATION FORECAST FOR TONIGHT...CURRENT RADAR OBS
INDICATE ANOTHER BAND OF SHOWERS WITH ISOLATED THUNDER OVER
WESTERN OHIO ASSOCIATED WITH FRONTAL FORCING ALONG THE COLD
FRONTAL BOUNDARY WITH ADDITIONAL ENHANCEMENT FROM INCREASED
INSOLATION/DIABATIC HEATING DUE TO A DRY SLOT MOVING ACROSS THAT
REGION. HRRR MODEL CURRENTLY HAS A GOOD HANDLE ON THE SHOWER
ACTIVITY...BRINGING IT INTO THE NIAGARA FRONTIER BY EARLY EVENING
AND QUICKLY FALLING APART BY THE TIME IT REACHES THE GENESEE
VALLEY AS INSTABILITY AND SYNOPTIC FORCING WEAKENS. WILL CARRY
LIKELY TO CATEGORICAL POPS FOR THE WESTERN COUNTIES WITH A SLIGHT
CHANCE OF THUNDER THIS EVENING TRANSITIONING TO CHANCE POPS FOR
THE EASTERN HALF OF THE FORECAST AREA.
COLD AIR FILTERING IN BEHIND THE COLD FRONT NECESSITATES A
DISCUSSION OF LAKE EFFECT POTENTIAL ON TUESDAY. WHILE 850MB TEMPS
GET NOMINALLY COLD ENOUGH FOR LAKE EFFECT...AROUND -10C TO -12C
ACROSS LAKE ERIE WITH A FAVORABLE WEST-SOUTHWEST WIND AND LOW
SHEAR...THE PRESENCE OF SUBSTANTIAL DRY AIR IN THE DENDRITIC GROWTH
ZONE AND AN INVERSION LEVEL RUNNING AT 5KFT OR LOWER IS NOT
IMPRESSIVE. THE REGIONAL GEM MODEL KEEPS THE DEEPER MOISTURE A
LITTLE FARTHER SOUTH...RESULTING IN A SLIGHTLY MORE FAVORABLE
PROFILE FOR SNOW. GIVEN THIS UNCERTAINTY...WILL KEEP POPS LIMITED TO
CHANCE EAST OF LAKE ERIE AND KEEP WEATHER LIMITED TO FLURRIES. EAST
OF LAKE ONTARIO...LONGER FETCH OFF OF THE LAKE AND SLIGHTLY COLDER
AIR IN THE LOWER LEVELS MAY RAISE THE INVERSION JUST ENOUGH TO
GENERATE SOME LIGHT SNOW SHOWERS...MAINLY ACROSS JEFFERSON AND LEWIS
COUNTIES...THOUGH ACCUMULATIONS WILL GENERALLY RUN IN THE
NEIGHBORHOOD OF 1-3 INCHES AT BEST.
PLENTY OF COLD AIR AND LAKE INDUCED CLOUD COVER IN PLACE WILL MAKE
FOR A TYPICAL DAY...FOR LATE JANUARY...WITH HIGHS RANGING FROM THE
UPPER 20S TO LOWER 30S ACROSS THE FORECAST AREA.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A PROGRESSIVE PATTERN WILL BE IN PLACE ACROSS NORTH AMERICA DURING
THIS PERIOD AS THE BROAD POLAR VORTEX THAT HAS BEEN IN PLACE OVER
CANADA WILL RETROGRADE TO ALASKA. THIS WILL KEEP A STRONG ZONAL JET
OVER THE GULF OF ALASKA AND PACIFIC NORTHWEST...WHICH WILL RESULT IN
A CONTINUAL FEED OF PACIFIC MODIFIED AIR OVER THE LOWER 48. OUR
TEMPERATURES WILL AVERAGE ABOVE NORMAL AS A RESULT...WITH LITTLE IN
THE WAY OF SIGNIFICANT WEATHER. THE DETAILS...
A SECONDARY COLD FRONT WILL DROP ACROSS THE LOWER GREAT LAKES ON
TUESDAY NIGHT...AND WHILE A VERY SHORT LIVED POCKET OF -10C H85 AIR
WILL SUPPORT SOME LAKE EFFECT EAST OF LK ONTARIO...SNOWFALL AMOUNTS
WILL NOT BE SIGNIFICANT. LAKE INDUCED CONVECTION EARLY ON SHOULD
DISINTEGRATE AS PACIFIC BASED AIR MOVES IN AND PUMPS H85`S TO -4C.
OTHERWISE...ANY NUISANCE SNOW SHOWERS ASSOCIATED WITH THE FRONTAL
PASSAGE WILL QUICKLY GIVE WAY TO CLEARING SKIES AS HIGH PRESSURE
WILL BUILD ACROSS ALL OF THE GREAT LAKES REGION.
WEDNESDAY SHOULD BE A FAIRLY NICE DAY ACROSS THE REGION AS A LARGE
AREA OF HIGH PRESSURE WILL DRIFT ACROSS PENNSYLVANIA. WILL BUMP MAX
TEMPS UP A BIT FROM CONTINUITY...AS H85`S ARE EXPECTED TO MODERATE
TO AROUND ZERO/-2C. THIS SHOULD SUPPORT AFTERNOON READINGS IN THE
MID 30S ACROSS THE LOWER ELEVATIONS...WHILE THE NORTH COUNTRY WILL
EXPERIENCE HIGHS CLOSER TO THE SEASONAL NORM IN THE UPPER 20S.
A WEAKLY DIVERGENT FLOW WILL ACCOMPANY A JET STREAK ACROSS THE LOWER
GREAT LAKES ON WEDNESDAY NIGHT...AND THIS WILL LIKELY LEAD TO AN
INCREASE IN CLOUD COVER. GIVEN THE DEARTH OF MOISTURE AND OVERALL
SYNOPTIC LIFT...WILL ONLY CARRY SLGT CHC POPS.
A POTENT SHORTWAVE WILL THEN DIG ACROSS THE UPPER MISSISSIPPI VALLEY
ON THURSDAY...AND THIS WILL HELP TO AMPLIFY AN ALREADY BULGING
SHORTWAVE RIDGE OVER OUR FORECAST AREA. WHILE THIS WILL PROMOTE FAIR
WEATHER ACROSS OUR REGION FOR THE BULK OF THE DAY...WE WILL
EXPERIENCE AN INCREASE IN CLOUD COVER AS LOW LEVEL MOISTURE WILL
POOL IN ADVANCE OF THE NEXT FRONTAL SYSTEM. THERE COULD EVEN BE A
COUPLE LIGHT RAIN SHOWERS IN THE AFTERNOON OVER THE FAR WESTERN
COUNTIES.
FOR THURSDAY NIGHT...OUR REGION WILL FIND ITSELF STRADDLED BY A PAIR
OF STORM SYSTEMS. THE AFOREMENTIONED UPPER MISSISSIPPI VALLEY SHORT
WAVE WILL TRACK ACROSS SOUTHERN ONTARIO WHILE A SFC LOW GENERATED IN
THE SOUTHERN BRANCH IS EXPECTED TO MAKE ITS WAY ACROSS THE
APPALACHIANS TO VIRGINIA. A PACIFIC BASED COLD FRONT STRETCHING
BETWEEN THE TWO WILL CROSS OUR FORECAST AREA DURING THE COURSE OF
THE NIGHT. SINCE FORCING BETWEEN THE TWO SYSTEMS SHOULD NOT BE VERY
STRONG...LIGHT LOW QPF SHOWERY PCPN COULD PROVE TO BE PROBLEMATIC AS
A WINTRY MIX WILL BE POSSIBLE.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
WHILE TEMPERATURES WILL AVERAGE ABOVE NORMAL FOR THE WEEKEND...IT
LOOKS AS IF WE WILL GET A SHOT OF SEASONABLY COLD AIR BY THE END OF
THIS PERIOD. KEEP IN MIND THAT THIS IS LOOKING OUT TO DAY 7...BUT
THERE IS A SUGGESTION BY THE MEDIUM RANGE PACKAGES THAT A
SIGNIFICANT SHORTWAVE WILL HELP TO AMPLIFY AN ALREADY EXISTING
TROUGH OVER THE EASTERN U.S.
THE ORIGINS OF THIS SHORTWAVE CAN BE SEEN IN WV IMAGERY OVER
NORTHERN SIBERIA. AS THIS IMPRESSIVE FEATURE WEAKENS...ENERGY WILL
BE EJECTED ACROSS THE HIGH ARCTIC TO ALASKA WHERE IT IS FORECAST TO
DISLODGE A CLOSED LOW. THE RESULTING SHORTWAVE WILL THEN DROP `DOWN
THE CHUTE` ACROSS BRITISH COLUMBIA TO THE CENTRAL U.S. AT THE START
OF THIS PERIOD...AND OVER THE NATIONS MID SECTION OVER THE COURSE OF
THE WEEKEND.
THIS WILL DEEPEN AND ENERGIZE THE EASTERN U.S. TROUGH WITH COLDER
AIR SETTLING OVER OUR REGION LATE IN THE WEEKEND AND EARLY NEXT
WEEK. SUCH A PATTERN WOULD ALSO LIKELY SPAWN A COASTAL STORM...BUT
THAT WOULD NOT BE AN ISSUE FOR OUR REGION. NOW...LETS LOOK AT THE
DETAILS ON A MORE LOCAL LEVEL.
SFC BASED RIDGING WILL MOVE ACROSS OUR REGION ON FRIDAY. THIS WILL
CLEAR OUT THE PCPN FROM WEST TO EAST WITH THE ONLY REMAINING MENTION
OF PCPN BEING OVER THE EASTERN LAKE ONTARIO REGION. H85 TEMPS IN THE
VCNTY OF -4C WILL SUPPORT AFTERNOON TEMPS IN THE 30S TO NEAR 40F.
THE RIDGE WILL MOVE EAST ON SATURDAY AS A DIGGING TROUGH WILL BE
FOUND OVER THE MISSISSIPPI VALLEY AND UPPER GREAT LAKES. THE
LOWERING HGTS ACROSS THE GREAT LAKES WILL HELP SOME COLDER AIR TO
SAG ACROSS THE FORECAST AREA WITH WINDS FRESHENING AS A RESULT OF
STRONGER WINDS BELOW H85.
IT WILL BECOME SOMEWHAT UNSETTLED SATURDAY NIGHT AND SUNDAY AS THE
BASE OF THE SHARPENED H5 TROUGH WILL SWING ACROSS THE LOWER GREAT
LAKES. IT WILL BECOME COLDER WITH SCATTERED SNOW SHOWERS AND
CONCENTRATED LAKE SNOWS SOUTHEAST OF THE LAKES.
FINALLY FOR SUNDAY NIGHT AND MONDAY...THE CORE OF THE COOLEST AIR
WILL BE MOVING ACROSS EASTERN CANADA WITH H85 TEMPS GENERALLY IN THE
MINUS TEENS FOR OUR FORECAST AREA. WHILE THIS WOULD PROMOTE SOME
LAKE EFFECT SNOWS...LOW LEVEL RIDGING SHOULD LIMIT ACCUMULATIONS.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
ALL TAF SITES EXCEPT JHW REMAIN AT VFR AS OF 18Z. KART VIS MAY DROP
INTO MVFR WITH LINE OF RAIN SHOWERS MOVING THROUGH BUT REMAIN VFR
OTHERWISE. JHW UNDER IFR CIGS AS A LOW LEVEL INVERSION WILL CONTINUE TO
KEEP LOW LEVEL MOISTURE TRAPPED NEAR THE SFC THERE.
WIND SHEAR STILL REMAINS AN ISSUE INTO THE AFTERNOON AS MODEL TIME
SECTIONS SHOW LOW LEVEL JET OF 50+ KTS AT 1-2 KFT. LLWS WILL REMAIN
POSSIBLE EVEN WITH GUSTY SURFACE WINDS DUE TO STRENGTH OF LLJ. A
COLD FRONT TO THE WEST OVER WESTERN OH WILL WORK ITS WAY EASTWARD
TOWARD THE AREA THIS EVENING. THE FRONT WILL BRING A SECOND AREA OF
RAIN SHOWERS ALONG THE BOUNDARY THEN VEERING WINDS TO SW WITH
COLD ADVECTION OCCURRING ALOFT. THIS WILL ERODE THE INVERSION AND
HIGHER WINDS WILL BE ABLE TO MIX DOWN TO THE SURFACE WITH GUSTS TO
40KTS POSSIBLE DURING THE EVENING POST FRONTAL. THE FRONT SHOULD
ALSO HELP TO IMPROVE JHW TO MVFR. CONDITIONS WILL NOT CHANGE MUCH
FOR THE SECOND HALF OF THE TAF PERIOD WITH MVFR CIGS AND GUSTY SW
WINDS EXPECTED.
ANOTHER CONCERN THAT WILL HAVE TO BE WATCHED EARLY TUESDAY IS THE
CHANCE FOR ZDR 09Z-12Z. RECENT NAM MODEL INDICATED SATURATED LOW
LEVELS WITH SUB-FREEZING TEMPS BUT DRY AIR IN THE SNOW GROWTH ZONE
COLD YIELD SOME PATCHY ZDR.
OUTLOOK...
WEDNESDAY...VFR.
THURSDAY AND FRIDAY...MAINLY VFR WITH A CHANCE OF RAIN/SNOW SHOWERS.
SATURDAY...VFR WITH CHANCE FOR SNOW SHOWERS.
&&
.MARINE...
A COLD FRONT WILL SWEEP ACROSS THE LAKES TONIGHT BRINGING FRESH
SOUTHWESTERLIES WITH A FEW GUSTS TO GALE FORCE POSSIBLE ACROSS
EASTERN LAKE ERIE. STRONG WINDS MIXING DOWN TO THE SURFACE MAY BRING
GALES TO THE OPEN WATERS OF WESTERN LAKE ONTARIO OVERNIGHT AS WELL.
SMALL CRAFT ADVISORY LEVEL WESTERLIES WILL REMAIN IN PLACE ACROSS
THE LAKES THROUGH MUCH OF TUESDAY NIGHT BEFORE HIGH PRESSURE BUILDS
ACROSS THE REGION WEDNESDAY...BRINGING A PERIOD OF CALMER WINDS AND
WAVES THAT WILL LAST INTO THURSDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WIND ADVISORY UNTIL 5 AM EST TUESDAY FOR NYZ001-002-010-011-
019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 6 PM EST TUESDAY FOR LEZ020.
GALE WARNING FROM 9 PM THIS EVENING TO 7 AM EST
TUESDAY FOR LOZ062.
SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR
LOZ042>045.
&&
$$
SYNOPSIS...WOOD
NEAR TERM...WOOD
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...SMITH
MARINE...WOOD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
236 PM CST MON JAN 23 2012
.SHORT TERM... /TONIGHT THROUGH THURSDAY/
THE FORECAST CHALLENGE FOR THE IMMEDIATE SHORT TERM WILL BE
TEMPERATURES AND SKY COVER...ESPECIALLY CHALLENGING OVER EASTERN
NORTH DAKOTA. THE CURRENT VISIBLE IMAGERY SHOWING THE DVL LAKE
BASIN IS CLEARING OUT AND WORKING ITS WAY DOWN THE SHEYENNE RIVER
BASIN. QUESTION IS HOW MUCH CONTRIBUTION HIGHER WINDS WILL MAKE
PRIOR TO SUNSET AS WINDS LIGHTEN UP. THE CURRENT NAM AND RUC H900
RH VALUES HAVE AN OKAY HANDLE ON THE CLEARING...BUT COULD BE
BETTER. THUS...QUESTION IS WHEN WILL THINGS CLEAR OUT AND HOW MUCH
TIME WILL TEMPS HAVE TO DIVE ESP IN AREAS OF FRESH SNOWFALL.
TONIGHT...CONTINUED TOWARD SLOWER CLEARING OF THE SKIES...WITH
MOST UNCERTAINTY OVER EASTERN ND WHERE SKIES ARE CURRENTLY CLEARING
OUT. SFC HIGH CURRENTLY OVER W CNTRL SD AND WILL DRIFT
EASTWARD...KEEPING ANY COMPLETE DECOUPLING AND THEREFORE COLDEST
TEMPERATURES IN SD. DO NOT EXPECT WINDS TO COMPLETELY DECOUPLE
OVER FGF CWA...WITH LIGHT NW WINDS BECOMING LIGHT AND SW OVER
NIGHT. SHOULD SKIES CLEAR OUT WHERE THE RIDGE AXIS/LIGHTEST WINDS
ARE...WILL NEED TO DROP TEMPS QUITE A BIT. BUT HAVE BUMPED UP
TEMPS QUITE A BIT ESP OVER NW AND W CNTRL MN...WHERE STRATUS IS
EXPECTED TO LINGER INTO TUE AM HOURS.
TUE AND TUE NIGHT...DRY UPPER WAVE WILL MOVE ACROSS CWA. TEMPS WILL BE
VERY DEPENDENT ON TONIGHTS LOWS AND STRATUS SITUATION TOMORROW
MORNING. CURRENTLY THINK FAR EASTERN ZONES WILL STILL BE OVC BUT
SCT OUT BY NOON...WITH REST OF CWA SEEING SOME DEG OF SOLAR. TEMPS
SHOULD RISE INTO 20S...WARMEST IN THE WEST.
WED AND WED NIGHT...LOW WILL MOVE ACROSS SOUTHERN CANADA...WITH
SFC BOUNDARY MOVING ACROSS NORTHERN TIES OF CONUS. LOOKS FOR
STRONGER SOUTHWESTERLY WINDS BECOMING WESTERLY WED NIGHT. THIS
WILL HELP BRING TEMPS UP INTO 30S...AND STRONG OVERNIGHT TEMPS
SHOULD KEEP WED NIGHT LOWS IN THE 20S. THERE IS A SLIGHT CHANCE
OVER SNOWFALL ACROSS NORTHERN ZONES WED AFTN INTO WED
NIGHT...HOWEVER WITH SFC LOW WELL NORTH OF CWA EXPECT ANY
ACCUMULATIONS TO BE MINIMAL. ALSO A CHANCE OF SOME LIQUID
PRECIP...BUT WITH LATEST THICKNESS VALUES HAVE CHANGED BACK TO ALL SNOW.
THU...WESTERLY WINDS THROUGHOUT DAY...WITH A CHANCE FOR SOME
LINGERING SNOW ACTIVITY IN FAR NORTHEAST AS LOW PRESSURE MOVES
INTO ONTARIO...AND OVER DVL REGION AS NEXT UPPER WAVE COMES
ACROSS. TEMPS SHOULD RISE INTO 30S GIVEN WARMER WED NIGHT LOWS.
.LONG TERM... /THU NIGHT THROUGH MONDAY/
MODELS CONTINUE TO BE IN FAIRLY DECENT AGREEMENT ON BRINGING WEAK
SHORTWAVES THROUGH THE NORTHWESTERLY FLOW...ALTHOUGH THERE ARE OF
COURSE MINOR DIFFERENCES IN TIMING. GIVEN THE UNCERTAINTY OF SUCH
MINOR SHORTWAVES AND WITH THE ENSEMBLE PRECIP PROBABILITIES
REMAINING FAIRLY LOW...WILL CONTINUE TO KEEP THE LOW POPS THAT
ALLBLEND GIVES US. AFTER SOME FAIRLY WARM TEMPERATURES AT THE
START OF THE PERIOD...THE DETERMINISTIC MODELS ARE IN GOOD
AGREEMENT ON BRINGING DOWN A DECENT COLD SURGE FOR THE WEEKEND AS
ONE OF THE SHORTWAVES HELPS TO AMPLIFY THE UPPER TROUGH TO OUR
EAST. TEMPS SHOULD RETURN CLOSER TO WHAT IS AVERAGE FOR THIS TIME
OF YEAR.
&&
.AVIATION...
SAT LOOP SHOWS THE CLEARING LINE AS MOVED EAST OF KDVL AND EXPECT
THAT IT WILL CONTINUE TO PUSH VERY SLOWLY EASTWARD OVERNIGHT. IFR
CEILINGS SHOULD GO UP TO MVFR BEFORE THE BACK EDGE OF THE CLOUDS
ARRIVE. THINK THAT KGFK AND KFAR SHOULD CLEAR OUT SOMETIME JUST
BEFORE 06Z WITH THE EASTERN TAF SITES NOT CLEARING OUT UNTIL THE
EARLY MORNING HOURS...IF THEY CLEAR OUT AT ALL. NORTHWEST WINDS
WILL DROP BELOW 12 KTS AND BECOME SOUTHERLY BY MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SPEICHER/JR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1233 PM EST MON JAN 23 2012
.SYNOPSIS...
STRONG COLD FRONT WHIPS THROUGH THIS AFTERNOON AND EARLY EVENING.
HIGH PRESSURE IN CONTROL TUESDAY AFTERNOON INTO WEDNESDAY. ANOTHER
SYSTEM PROVIDES RAIN WEDNESDAY NIGHT INTO THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
MUCH OF THE SHOWER ACTIVITY HAS DECREASED FROM WEST TO EAST.
COLD FRONT STILL REMAINS WELL TO THE WEST ACROSS INDIANA. BOTH
RADAR AND HRRR MODEL SEEM TO BE INDICATING ANOTHER LINE OF
CONVECTION DEVELOPING OUT AHEAD OF THIS FRONT AS IT PUSHES EAST
INTO THE AREA. SPC HAS SOUTHEAST OHIO IN A SEE TEXT. STILL SOME
UNCERTAINTY AS TO WHETHER THUNDERSTORMS WILL BE ABLE TO
DEVELOP...OR JUST CONVECTIVE SHOWERS...DUE TO WARM AIR ALOFT. FOR
NOW...ADDED ISOLD THUNDER...MAINLY TO SOUTHEAST OHIO ZONES FOR
THIS AFTERNOON AS THE FRONT PUSHES TOWARDS THE REGION. IF ANY
DEEPER CONVECTION IS ABLE TO FORM...STRONGER WINDS ALOFT MAY BE
ABLE TO MIX DOWN TOWARDS THE SURFACE. WILL LET THE WIND ADVISORY
RIDE FOR NOW...AND WILL PROBABLY JUST LET EVENING SHIFT DECIDE
WHETHER TO CANCEL IT EARLY. OTHERWISE...MADE NO MAJOR CHANGES TO
THE FORECAST.
PREVIOUS DISCUSSION...
ALL EYES ARE ON THE LONG LINE OF CONVECTION NOW MOVING ACROSS THE
TENNESSEE AND LOWER OHIO VALLEYS. THIS LINE IS IN ADVANCE OF A COLD
FRONT...WHICH WILL CROSS A BIT LATER THAN THOUGHT PREVIOUSLY...
SOMETHING LIKE THE 20Z TO 03Z RANGE. BEFORE THEN...HAVE SOLID 100
POPS WITH THE MAIN PRECIP LINE...WHICH MOVES THROUGH BETWEEN 10Z AND
15Z. NUMBER OF LIGHTNING STRIKES IS INCHING DOWNWARD...STILL PLENTY
ENOUGH FOR MAINTAINING THUNDER MENTION.
MAIN CONCERN TODAY WILL BE WIND GUSTS. H850 JET OF 60-70
KNOTS WILL REACH THE TRI-STATE AREA BY 12Z...BEFORE WEAKENING AS THE
SURFACE/UPPER LOWS ROTATE NORTH INTO THE GREAT LAKES. STILL SEEING
A FAIRLY STOUT LOW LEVEL INVERSION WHICH WILL KEEP THE STRONGEST OF
THE WINDS ALOFT...KEEPING THE RISK OF SEVERE CONVECTIVE GUSTS IN
CHECK. HOWEVER...LINE OF SHRA/TSRA MAY BE ENOUGH TO DRAG DOWN 30-40
KNOT GUSTS ALONG AND IMMEDIATELY BEHIND THE LINE...AND PLAYED IT
THIS WAY IN THE GRIDS. ONCE INVERSION MIXES OUT LATER
TODAY...SHOULD CONTINUE TO SEE 20-30 KNOT GUSTS. GOING TO CONTINUE
WITH WIND ADVISORY...ALTHOUGH COULD SEE IT BEING CANCELLED BEFORE
EXPIRATION AT 02Z.
DID GO AHEAD AND CANCEL THE FREEZING RAIN ADVISORY FOR THE EASTERN
SLOPES EARLY. WITH TEMPERATURES STRUGGLING TO STAY BELOW FREEZING
AND LACK OF PRECIPITATION...ICE ACCRETION THREAT IS LOOKING MINOR.
STILL COULD SEE A FEW POCKETS AROUND SUNRISE THOUGH.
BEHIND THE MAIN CONVECTIVE LINE...SCATTERED SHOWERS MAY
LINGER...ESPECIALLY ACROSS THE NORTH...AS MAIN H500 TROUGH AXIS/VORT
MAX SKIRTS THE AREA. LINGERING MOISTURE PLUS PEDESTRIAN COLD
ADVECTION MAY BE ENOUGH TO CONTINUE SHRA INTO THE EVENING BEFORE
FROPA. LIMITED POPS TO CHANCE WITH THIS ACTIVITY.
HIGH PRESSURE MOVES FROM THE ARKLATEX INTO THE TENNESSEE VALLEY
TONIGHT...WITH SOUTHWEST FLOW PUSHING DRIER AIR INTO THE REGION.
CLOUDS WILL LINGER ACROSS THE NORTH WHILE SKIES CLEAR ELSEWHERE
ESPECIALLY SOUTH/WEST OF I-64. PRECIPITATION MAY END AS SNOWFLAKES
ON THE HIGHEST RIDGES OVERNIGHT...CANNOT RULE OUT FLURRIES THROUGH 12Z.
DID NOT CHANGE TEMPERATURES TOO MUCH FROM PREVIOUS FORECAST. DID
GENERALLY NUDGE TOWARD LOWER MOS NUMBERS TODAY.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
WAS A BIT COOLER ON MAXIMUM TEMPERATURES ON TUESDAY...EVEN THOUGH
SOUTHERN AND WESTERN COUNTIES SHOULD SEE PLENTY OF AFTERNOON
SUNSHINE...THE 850 MB THERMAL TROF HANGS OVER US THROUGH 18Z. DID
INCREASE THE STRATOCUMULUS CLOUDS ON TUESDAY...ESPECIALLY NE OF
CRW. INCLUDED SOME SPRINKLES OR FLURRIES IN THE CKB TO EKN AND
CNTRL WV MOUNTAIN CORRIDOR INTO TUESDAY AFTERNOON. WINDS SHOULD
STILL BE QUITE NOTICEABLE DURING THE DAY.
PEACEFUL TUESDAY NIGHT STILL EXPECTED.
HIGH CLOUDS INCREASE WEDNESDAY...AND WITH LIGHT WINDS...HELD DOWN
TEMPERATURES A FEW DEGREES.
TIMING THE INITIAL PCPN STILL UNCERTAIN...SO NO REASON TO ADJUST
MUCH WITH WEDNESDAY NIGHT.
THE 00Z ECWMF HAS COME MORE IN LINE WITH THE GFS ON SPEED OF
SOUTHERN 500 MB TROF MOVING EAST. CANADIAN STILL A BIT SLOWER.
A GOOD SSW 850 MB FEED OF DEW POINTS AROUND 8C INTO AN EAST TO WEST
BAROCLINIC ZONE OVER US. SO A BIT CONCERNED AT THIS DISTANCE IN
TIME...ON SOME HEAVIER RAIN AND MAYBE WATER ISSUES. WILL INCREASE
POPS THURSDAY INTO THURSDAY EVENING TO LIKELY ESPECIALLY FOR MUCH OF
THE CWA.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LOTS OF VARIABILITY BETWEEN MODELS IN THIS PERIOD...LEADING TO A
LOW CONFIDENCE FORECAST. USED A BLEND OF THE GFS AND UKMET FOR
THURSDAY AND FRIDAY...THEN WENT MORE TOWARD THE GFS FOR SATURDAY AND
SUNDAY. THIS WOULD PROVIDE A SOUTHERN STREAM SYSTEM FOR WEDNESDAY
NIGHT AND THURSDAY...FOLLOWED BY ANOTHER FRIDAY NIGHT AND SATURDAY.
BEHIND THE SATURDAY SYSTEM...COLDER AIR MAY MOVE INTO THE REGION.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
18Z MONDAY THROUGH 18Z TUESDAY...
ANOTHER ROUND OF CONVECTION IS APPROACHING THE AREA FROM THE WEST.
THIS WILL PRIMARILY AFFECT SOUTHEAST OHIO...EASTERN KENTUCKY...AND
NORTHERN WEST VIRGINIA. THERE IS THE POSSIBILITY OF STRONG WIND
GUSTS OF UP TO 50 KTS WITH ANY CONVECTION. BRIEF MVFR CAN ALSO BE
EXPECTED IN CONVECTION. ANY SHOWER/STORM ACTIVITY SHOULD START TO
DIE DOWN AFTER 00-03Z AS THE COLD FRONTAL BOUNDARY PUSHES THROUGH
THE AREA.
IN ADDITION TO ANY SHOWER/STORM ACTIVITY...STRONG WINDS ALOFT MAY MIX
DOWN THIS AFTERNOON...WITH GUSTS OF UP TO 40 KTS POSSIBLE.
OCCASIONAL GUSTS OF OVER 40 KTS MAY BE POSSIBLE OVER THE HIGHER
TERRAIN.
HIGH PRESSURE WILL BUILD IN FROM THE WEST LATE TONIGHT...FOR A
GRADUAL CLEARING TREND FROM SOUTHWEST TO NORTHEAST...AND FOR A
GRADUAL DECREASE IN WINDS OVERNIGHT. WINDS WILL BE GUSTY AGAIN
TOMORROW...MAINLY AFTER 15Z...WITH THE ONSET OF DAYTIME HEATING.
HOWEVER...WINDS ARE NOT EXPECTED TO BE AS GUSTY...WITH GUSTS IN
THE TEEN TO 20 KT RANGE EXPECTED.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: THERE MAY BE MORE WIDESPREAD CONVECTION THAN
CURRENTLY FORECAST. WINDS MAY NOT BE AS STRONG AS CURRENTLY
FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY M M M M M M L H H H H H
HTS CONSISTENCY M M M M M H H H H H H H
BKW CONSISTENCY L L M M L L L H H H H H
EKN CONSISTENCY M M M L L L L M M H H H
PKB CONSISTENCY M M M M M M M H H H H H
CKB CONSISTENCY H H H H M M M H H H H H
AFTER 18Z TUESDAY...
IFR POSSIBLE WEDNESDAY NIGHT INTO THURSDAY NIGHT IN LOW
CLOUDS...RAIN...AND FOG.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR WVZ005>011-
013>020-024>040-046-047.
OH...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR OHZ066-067-075-
076-083>087.
KY...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR KYZ101>103-105.
VA...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR VAZ003-004.
&&
$$
SYNOPSIS...KTB/CL
NEAR TERM...CL/SL
SHORT TERM...KTB
LONG TERM...RPY
AVIATION...SL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
602 PM EST MON JAN 23 2012
.SYNOPSIS...
AN OCCLUDED FRONT WILL PUSH ACROSS CENTRAL PA TONIGHT. HIGH
PRESSURE WILL BRING DRIER CONDITIONS AND ABOVE NORMAL TEMPERATURES
FOR THE MID WEEK PERIOD.
THE NEXT SYSTEM SLATED TO BRING UNSETTLED WEATHER SHOULD ARRIVE
LATER THURSDAY OR FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
COLD FRONT MOVING INTO WESTERN PA THIS EVENING...ACCOMPANIED BY A
BROKEN LINE OF SHRA AND EVEN A FEW LIGHTNING STRIKES ACROSS THE NW
MTNS. RUC STABILITY INDICES SUGGEST THE NW MTNS ARE THE ONLY AREA
SUSCEPTIBLE TO LIGHTNING BTWN 23Z-01Z. ELSEWHERE...EXPECT SHOWERS TO
DWINDLE AS THEY MOVE INTO THE STABLE AIR MASS ENTRENCHED EAST OF
THE ALLEGHENIES. EVENING POPS RANGE FROM NR 100 PCT ACROSS THE NW
MTNS...TO ARND 10 PCT LOWER SUSQ VALLEY.
FRONT WILL COME THRU THE CENTRAL COUNTIES LATER THIS
EVENING...ACCOMPANIED BY THE CHC OF A -SHRA AND BRIEFLY RISING
TEMPS AS LOW LVL INVERSION BREAKS. FURTHER EAST...AREAS OF FOG
WILL BE THE BIGGEST CONCERN THIS EVENING OVR THE SUSQ VALLEY /HARRISBURG
DOWN TO 1/2SM AT 22Z/. HOWEVER...ARRIVAL OF OCCLUDED FRONT WILL
BRING DRIER WESTERLY FLOW AND LIKELY DISPERSE THE FOG LATE
TONIGHT.
BEHIND THE FRONT WE WILL TRANSITION TO A MORE TYPICAL COOL AIR
ADVECTION REGIME. RESIDUAL LOW LVL MOISTURE ASCENDING THE
ALLEGHENIES ON WSW FLOW WILL LIKELY PRODUCE SCT -SHSN LATER
TONIGHT. MDL QPF SUGGESTS A LIGHT DUSTING IS POSSIBLE OVR THE NW
MTNS BY DAWN.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
WEST TO WEST-SOUTHWEST SFC WINDS WILL GUST IN THE 20 TO 25 MPH
RANGE TUESDAY BEFORE DIMINISHING AS THE DAY WEARS ON. SOME SNOW
SHOWER ACTIVITY CAN BE EXPECTED OVER WESTERN HIGH TERRAIN BUT THE
POST FRONTAL AIR ISN`T TERRIBLY COLD SO WE ARE NOT EXPECTING MORE
THAN NUISANCE ACCUMS OF SNOW OVER THE LAURELS AND NW MOUNTAINS.
MAX TEMPS IN THE WAKE OF THE COLD/OCCLUDED FRONT WILL NOT BE ALL
THAT COLD. IN FACT...AFTERNOON HIGHS TUESDAY WILL BE SOME 5-8F
ABOVE NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
WEAK NORTHERN-SOUTHERN STREAM COUPLED RIDGING OVER THE MID ATLC AT
THE START OF THE PERIOD WILL GIVE WAY TO FLAT NORTHERN STREAM
FLOW FOR A DAY OR TWO BEFORE A STRONGER SOUTHERN STREAM TROF
LIFTS INTO THE EAST U.S. LATE IN THE WEEK. NORTHERN STREAM ENERGY
ON THE HEELS OF THE SRN TROF LOOKS TO FORM A LARGE BUT PROGRESSIVE
UPPER TROF OVER THE NERN NOAM BY THE END OF THE PERIOD.
RIDGING WILL SUPPORT DRY CONDS WED INTO EARLY THURS BEFORE THE
APPROACHING SRN STREAM TROF LIFTS TOWARD THE REGION...WITH A SFC
LOW EXPECTED NEAR DC BY FRIDAY MORNING. GIVEN CLIMATOLOGICALLY
COLD AIR IN PLACE A SNOWSTORM WOULD BE PRETTY LIKELY...BUT AGAIN
THIS TIME AROUND AT LEAST SOME OF THE AREA WILL BE ALL RAIN WITH A
MIX OVER MOST OF CENTRAL PA. THE NORTHERN STREAM WAVE WILL PULL A
COLD FRONT ACROSS THE STATE ON SATURDAY. THE RESULTING UPPER LOW
OVER NERN NOAM WILL KEEP A COLD WESTERLY TO NWRLY FLOW OVER PA
FROM SUNDAY INTO MONDAY WITH SCTD SNOW SHOWERS MAINLY IN THE MTNS.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS EXPECTED...FAR WESTERN AREAS CLEAR NOW...STILL SLOW TO MOVE
LOW CLDS OUT AT AOO AND UNV. DID NOT EXPECT LOW CLDS TO CLEAR
PRIOR TO 00Z ACROSS THE EAST. LLWS WILL CONTINUE TO BE AN ISSUE
FOR A FEW MORE HOURS...ALONG WITH LOW CLDS.
ALSO SOME CHC OF A HEAVY SHOWER...EVEN A RUMBLE OF THUNDER
ACROSS THE FAR WEST.
MDT RIGHT AT FREEZING...TEMP SHOULD SLOWLY EDGE UP FEW
DEGREES THERE THE NEXT FEW HOURS.
21Z TAFS ADJUSTED.
EARLIER DISCUSSION BELOW.
WIDESPREAD IFR WILL CONTINUE UNTIL THE FRONT APPROACHES AND
GUSTY WEST WINDS ALLOW FOR SOME MIXING AND DRYING. THE TIME FRAME
FOR WIDESPREAD IMPROVEMENT WILL BE LATER THIS EVENING AND
OVERNIGHT WITH COLD AIR DAMMING EXPECTED TO HOLD TOUGH FOR THE
REMAINDER OF THE DAYLIGHT HOURS.
BFD/JST ACTUALLY MAY BENEFIT FROM THE DRY SLOT RACING INTO WRN
PA THIS AFTERNOON...POSSIBLY ALLOWING THEM TO QUICKLY SHOOT UP TO
VFR...BUT TIMING THIS IS NEXT TO IMPOSSIBLE AS CLOUDS TEND TO WANT
TO STAY LOCKED IN EAST OF THE MOUNTAINS.
AFTER THE FRONT PASSES WE WILL THEN TRANSITION INTO A FAMILIAR
COLD SEASON PATTERN WHERE WESTERN HIGH TERRAIN REMAINS MVFR/IFR
WITH SCATTERED SNOW SHOWERS...AND MUCH OF THE REMAINDER OF THE
REGION IMPROVES TO VFR.
OUTLOOK...
TONIGHT...COLD FROPA/GUSTY WIND SHIFT TO THE WEST. IMPROVING
CONDITIONS OVER ALL BUT THE WESTERN HIGH TERRAIN.
TUESDAY...MVFR IN -SHSN N/W...VFR E OF MTNS.
WED...MVFR/SNOW SHOWERS NW POSSIBLE. NO SIG WX ELSEWHERE.
THU...MVFR/IFR DEVELOPING WITH POSSIBLE WINTRY MIX OF PRECIP.
FRI...VFR MOST OF THE AREA...BUT MVFR AND IFR ACROSS THE WESTERN
MOUNTAINS WITH SNOW SHOWERS...ESPECIALLY EARLY.
SAT...MAINLY VFR...BUT MVFR POSSIBLE AT JST AND BFD WITH
LOWER CLDS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1125 AM CST MON JAN 23 2012
.DISCUSSION.../ISSUED AT 955 AM CST/
SNOW IS NOW WELL TO THE EAST OF OUR AREA LATE THIS MORNING. MAIN
CHALLENGE FOR THE REMAINDER OF THE DAY WILL BE CLOUD COVER AND HOW
QUICKLY WINDS WILL TAPER DOWN. NOW THINKING CLOUDS WILL HOLD FOR
MUCH OF THE DAY...WITH A SOLID STRATUS DECK PRESENTLY HANGING BACK
INTO CENTRAL SOUTH DAKOTA...AND RUC RH TIME SECTIONS INDICATING HIGH
925/850 MB RH HOLDING UNTIL 21Z THEN MOVING OUT FROM WEST TO EAST.
WINDS ARE BEGINNING TO SHOW SIGNS OF DIMINISHING FROM THE WEST...AND
WOULD EXPECT THIS TREND TO CONTINUE THROUGH THE AFTERNOON AS
GRADIENT RELAXES AND COLD AIR ADVECTION TRANSITIONS TO NEUTRAL TO
WARM AIR ADVECTION LATER IN THE AFTERNOON. TEMPERATURES LOOKING TO
BE ON TRACK...REMAINING NEARLY STEADY TO FALLING SLIGHTLY WITH
AFTERNOON READINGS IN THE UPPER TEENS TO LOWER 20S. UPDATES OUT.
&&
.AVIATION.../18Z TAF ISSUANCE/
MVFR CEILINGS WILL PERSIST ACROSS THE AREA THROUGH 21Z...BEFORE
DECREASING FROM THE WEST THROUGH THE EARLY EVENING. BREEZY
NORTHWESTERLY WINDS AND FRESH SNOW COVER WILL RESULT IN REDUCED
VISIBILITIES...IN THE RANGE OF 3 TO 5 SM OVER PORTIONS OF
SOUTHWESTERN MINNESOTA AND NORTHWESTERN IOWA THROUGH THE AFTERNOON.
THESE WINDS WILL DECREASE RAPIDLY AFTER 00Z TONIGHT AS HIGH PRESSURE
BUILDS INTO THE REGION...BECOMING LIGHT AND VARIABLE BY 04Z.
&&
.PREV DISCUSSION.../ISSUED AT 305 AM CST/
SNOW HAS TAPERED OFF TO FLURRIES MOST PLACES EXCEPT FAR EAST
WHERE ANOTHER HALF INCH OF SNOW MAY OCCUR. WILL LEAVE ADVISORY
GOING FAR EAST UNTIL 12Z AND THEN END. WINDS ARE INCREASING TO 20
TO 35 MPH BUT NOT REALLY REDUCING VISIBILITY WITH BLOWING MOST
PLACES AS COLD AIR ADVECTION IS NOT ALL THAT STRONG AND SNOW THAT
FELL HAD A HIGHER MOISTURE CONTENT. SO WILL JUST GO WITH PATCHY
BLOWING SNOW OUTSIDE OF ADVISORY AREA THIS MORNING.
SKIES WILL BE SLOW TO CLEAR ACROSS THE EASTERN CWA TODAY WITH
CYCLONIC FLOW ALOFT...BUT SHOULD BEGIN TO CLEAR ACROSS THE WEST BY
LATE MORNING OR EARLY AFTERNOON. TEMPERATURES ARE LIKELY CLOSE TO
THEIR HIGHS EARLY THIS MORNING AND WILL LIKELY CONTINUE TO FALL
THROUGH 15 OR 16Z AND THEN REBOUND ONLY A FEW DEGREES.
SURFACE HIGH WILL SETTLE OVER CWA TONIGHT AND WITH CLEAR SKIES AND
LIGHT WINDS...TEMPERATURES WILL FALL BELOW ZERO MOST
LOCATION...EXCEPT FAR SOUTHWEST WITH LIGHT RETURN FLOW WILL PROBABLY
KEEP TEMPERATURES FALLING BELOW THE SINGLE DIGITS.
WILL BE A DECENT GRADIENT WITH TEMPERATURES ACROSS THE CWA ON
TUESDAY. LIGHT WINDS AND FRESH SNOW COVER ACROSS THE EAST WILL MAKE
IT HARD TO WARM WITH LACK OF ANY REAL MIXING MECHANISM SO LOWER 20S
MAY BE AS WARM AS IT GETS. SLIGHTLY LITTLE BETTER MIXING ACROSS THE
WEST SHOULD ALLOW HIGHS TO CLIMB INTO THE MID 20S TO LOWER 30S.
WEAK SHORT WAVE WILL MOVE ACROSS CWA TUESDAY NIGHT WITH INCREASING
CLOUDS AHEAD OF THIS SYSTEM TUESDAY AFTERNOON AND NIGHT. WILL LEAVE
FORECAST DRY AS LOW LEVELS REMAIN DRY...BUT COULD SQUEEZE OUT A FEW
FLURRIES OR A TENTH OR TWO OF SNOW WITH THIS FEATURE. CLOUD COVER
WILL ALSO HOLD TEMPERATURE UP TUESDAY NIGHT...ESPECIALLY SOUTH WHERE
SKIES WILL BE MOSTLY CLOUDY THROUGH THE NIGHT.
WARMER WEATHER CAN BE EXPECTED ACROSS THE CWA WEDNESDAY INTO FRIDAY
WITH SNOW COVER KEEPING MOST OF CWA FROM MIXING OUT TO TRUE
POTENTIAL. SHORT WAVE PROGGED TO DROP SOUTHEAST ACROSS CWA ON FRIDAY
AND WILL KEEP SMALL CHANCE OF PRECIPITATION ACROSS SOUTHERN CWA.
MODELS STILL DIFFER ON THIS FEATURE SO NOT CONFIDENT YET IN RAISING
THE SMALL POPS.
WILL SEE COOLER TEMPERATURES NEXT WEEKEND AS COOLER HIGH BUILDS IN
FROM CANADA. NOT AN ARCTIC BLAST...BUT SHOULD COOL TEMPERATURES OFF
AROUND 5 TO 10 DEGREES.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
955 AM CST MON JAN 23 2012
.DISCUSSION...
SNOW IS NOW WELL TO THE EAST OF OUR AREA LATE THIS MORNING. MAIN
CHALLENGE FOR THE REMAINDER OF THE DAY WILL BE CLOUD COVER AND HOW
QUICKLY WINDS WILL TAPER DOWN. NOW THINKING CLOUDS WILL HOLD FOR
MUCH OF THE DAY...WITH A SOLID STRATUS DECK PRESENTLY HANGING BACK
INTO CENTRAL SOUTH DAKOTA...AND RUC RH TIME SECTIONS INDICATING HIGH
925/850 MB RH HOLDING UNTIL 21Z THEN MOVING OUT FROM WEST TO EAST.
WINDS ARE BEGINNING TO SHOW SIGNS OF DIMINISHING FROM THE WEST...AND
WOULD EXPECT THIS TREND TO CONTINUE THROUGH THE AFTERNOON AS
GRADIENT RELAXES AND COLD AIR ADVECTION TRANSITIONS TO NEUTRAL TO
WARM AIR ADVECTION LATER IN THE AFTERNOON. TEMPERATURES LOOKING TO
BE ON TRACK...REMAINING NEARLY STEADY TO FALLING SLIGHTLY WITH
AFTERNOON READINGS IN THE UPPER TEENS TO LOWER 20S. UPDATES OUT.
&&
.PREV DISCUSSION.../ISSUED AT 305 AM CST/
SNOW HAS TAPERED OFF TO FLURRIES MOST PLACES EXCEPT FAR EAST
WHERE ANOTHER HALF INCH OF SNOW MAY OCCUR. WILL LEAVE ADVISORY
GOING FAR EAST UNTIL 12Z AND THEN END. WINDS ARE INCREASING TO 20
TO 35 MPH BUT NOT REALLY REDUCING VISIBILITY WITH BLOWING MOST
PLACES AS COLD AIR ADVECTION IS NOT ALL THAT STRONG AND SNOW THAT
FELL HAD A HIGHER MOISTURE CONTENT. SO WILL JUST GO WITH PATCHY
BLOWING SNOW OUTSIDE OF ADVISORY AREA THIS MORNING.
SKIES WILL BE SLOW TO CLEAR ACROSS THE EASTERN CWA TODAY WITH
CYCLONIC FLOW ALOFT...BUT SHOULD BEGIN TO CLEAR ACROSS THE WEST BY
LATE MORNING OR EARLY AFTERNOON. TEMPERATURES ARE LIKELY CLOSE TO
THEIR HIGHS EARLY THIS MORNING AND WILL LIKELY CONTINUE TO FALL
THROUGH 15 OR 16Z AND THEN REBOUND ONLY A FEW DEGREES.
SURFACE HIGH WILL SETTLE OVER CWA TONIGHT AND WITH CLEAR SKIES AND
LIGHT WINDS...TEMPERATURES WILL FALL BELOW ZERO MOST
LOCATION...EXCEPT FAR SOUTHWEST WITH LIGHT RETURN FLOW WILL PROBABLY
KEEP TEMPERATURES FALLING BELOW THE SINGLE DIGITS.
WILL BE A DECENT GRADIENT WITH TEMPERATURES ACROSS THE CWA ON
TUESDAY. LIGHT WINDS AND FRESH SNOW COVER ACROSS THE EAST WILL MAKE
IT HARD TO WARM WITH LACK OF ANY REAL MIXING MECHANISM SO LOWER 20S
MAY BE AS WARM AS IT GETS. SLIGHTLY LITTLE BETTER MIXING ACROSS THE
WEST SHOULD ALLOW HIGHS TO CLIMB INTO THE MID 20S TO LOWER 30S.
WEAK SHORT WAVE WILL MOVE ACROSS CWA TUESDAY NIGHT WITH INCREASING
CLOUDS AHEAD OF THIS SYSTEM TUESDAY AFTERNOON AND NIGHT. WILL LEAVE
FORECAST DRY AS LOW LEVELS REMAIN DRY...BUT COULD SQUEEZE OUT A FEW
FLURRIES OR A TENTH OR TWO OF SNOW WITH THIS FEATURE. CLOUD COVER
WILL ALSO HOLD TEMPERATURE UP TUESDAY NIGHT...ESPECIALLY SOUTH WHERE
SKIES WILL BE MOSTLY CLOUDY THROUGH THE NIGHT.
WARMER WEATHER CAN BE EXPECTED ACROSS THE CWA WEDNESDAY INTO FRIDAY
WITH SNOW COVER KEEPING MOST OF CWA FROM MIXING OUT TO TRUE
POTENTIAL. SHORT WAVE PROGGED TO DROP SOUTHEAST ACROSS CWA ON FRIDAY
AND WILL KEEP SMALL CHANCE OF PRECIPITATION ACROSS SOUTHERN CWA.
MODELS STILL DIFFER ON THIS FEATURE SO NOT CONFIDENT YET IN RAISING
THE SMALL POPS.
WILL SEE COOLER TEMPERATURES NEXT WEEKEND AS COOLER HIGH BUILDS IN
FROM CANADA. NOT AN ARCTIC BLAST...BUT SHOULD COOL TEMPERATURES OFF
AROUND 5 TO 10 DEGREES.
&&
.AVIATION.../12Z TAF ISSUANCE/
AN MVFR DECK OF CLOUDS WILL PLAGUE THE TAF SITES THIS
MORNING...UNDER THE INFLUENCE OF CYCLONIC FLOW. SOME MINOR
VISIBILITY RESTRICTIONS DUE TO LIGHT SNOW AND BLOWING SNOW OVER
FAR ERN SD...NW IA AND SW MN THIS MORNING...BUT THAT SHOULD OCCUR
TO THE EAST OF THE TAF SITES FOR THE MOST PART. THINK IT WILL BE
AFTER 18Z BEFORE NOTABLE CLEARING IS SEEN AT KHON...AND UNTIL
CLOSER TO 21Z FOR KFSD AND KSUX BEFORE CIGS BREAK OUT. BY
00Z...MOSTLY CLEAR SKIES SHOULD BE PREVALENT...ALONG WITH A
SIGNIFICANT REDUCTION IN WIND SPEEDS AS HIGH PRESSURE SETTLES IN.
WINDS WILL BECOME LIGHT AND VARIABLE AFTER MIDNIGHT...WITH ONLY
FLEETING CIRRUS EXPECTED IN THE WAY OF ANY CLOUD COVER OVERNIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
846 AM PST Mon Jan 23 2012
.SYNOPSIS...Snow showers will linger over the central and
southern Idaho Panhandle this morning as a weak cold front exits
the region. The rest of the Inland Northwest will experience dry
conditions today and tonight. The next storm system will bring
another round of wintry weather Tuesday. Warmer conditions are
expected Wednesday and Thursday with snow levels above the valley
floors.
&&
.DISCUSSION...
Updated the forecast to take down the Winter Weather Advisory for
Idaho zone 4. Radar shows the backedge of the snow shield has
exited the region followed by clearing of the high clouds. Little
wind and abundant low level moisture has lead to stratus and
fog...locally dense. The Dense Fog Advisory will continue through
10am, although the HRRR models suggests the fog may persist a
little longer. /rfox.
&&
.AVIATION...
12Z TAFS: Cold front will continue to sag to the southeast of the
KPUW and KLWS taf sites through the morning hours with the threat of
precip diminishing. The main concern for today is the fog and low
stratus that has developed in the wake of this system. This
fog/stratus is expect to hang around through at least the early
afternoon hours. We should then see this fog/stratus lift and
scatter out by the late afternoon. Winds will shift to out of the
east tonight with moisture likely to pool up across the western
basin. As a result, KMWH and KEAT will see the best chance low
stratus and fog continuing or redeveloping tonight into tomorrow
morning. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 33 19 33 33 41 35 / 10 0 40 80 30 60
Coeur d`Alene 34 18 34 31 42 35 / 10 0 30 80 50 80
Pullman 34 23 37 33 45 39 / 10 0 30 90 40 70
Lewiston 41 25 40 37 49 41 / 10 0 20 80 30 60
Colville 35 19 33 31 40 32 / 10 10 60 80 40 70
Sandpoint 34 21 34 31 41 35 / 10 0 30 80 60 80
Kellogg 34 20 32 32 42 35 / 10 0 20 90 70 90
Moses Lake 32 18 32 32 42 35 / 0 0 90 30 20 30
Wenatchee 27 20 30 30 37 36 / 0 0 90 20 20 30
Omak 32 18 30 27 39 29 / 10 10 80 20 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Dense Fog Advisory until 10 AM PST this morning for Moses Lake
Area-Upper Columbia Basin-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1218 PM CST MON JAN 23 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
245 AM CST MON JAN 23 2012
FORECAST CONCERNS FOCUS ON THE SNOW THIS MORNING.
LATEST WATERVAPOR IMAGERY DEPICTED AN UPPER LEVEL SHORTWAVE TROUGH
CHURNING ACROSS THE SOUTHERN PLAINS...WHILE AT THE SFC A LOW WAS
LOCATED OVER NORTHERN MO. 88-D RADAR IMAGERY SHOWED AREAS OF PCPN
SPREADING FROM THE DAKOTAS ACROSS MN/IA...AND ACROSS SOUTHERN WI AND
ILL. WHAT WAS FALLING WAS DEPENDENT ON SFC TEMPS AND WHETHER OR NOT
ANY ICE WAS IN THE CLOUD.
23.00Z ARE IN GOOD AGREEMENT WITH LIFTING THE TROUGH NORTHEAST
ACROSS THE REGION TODAY...AND OVER SOUTHEAST CANADA TONIGHT. THE
BULK OF THE ASSOCIATED QG CONVERGENCE WITH THE UPPER LEVEL FORCING
EXITS THE FORECAST AREA BY 18Z...AS DOES ANY ISENTROPIC UPGLIDE ON
THE 275-295 K SFCS. X-SECTIONS POINT TO SOME 2-D FRONTOGENETIC
FORCING...BUT THIS ALSO LIFTS TO THE NORTHEAST BY 18Z.
AS IT LOOKS NOW...THE BULK OF ANY ACCUMULATING PCPN SHOULD BE THIS
MORNING...WITH PERHAPS SOME LIGHT PCPN LINGERING INTO THE AFTERNOON
ACROSS NORTHERN AREAS. RUC13 BUFKIT SOUNDINGS SATURATE ENOUGH THAT
ICE IS INTRODUCED INTO THE CLOUD BY 3 AM...SO SNOW SHOULD BE THE
MAIN PCPN TYPE. MAIN MASS OF PCPN MOVING ACROSS THE REGION IS
ASSOCIATED WITH THE UPPER LEVEL TROUGH/QG CONVERGENCE. THE
DEFORMATION BAND NORTHWEST OF THE LOW HAS TWO AREAS...ONE FAIRLY
NARROW. THIS WAS IMPACTING WESTERN MN/WESTERN IA. THE MISH-MASH OF
DIFFERENT AREAS MAKES IT HARDER TO REFINE SNOW AMOUNTS FOR THIS
MORNING...BUT LOCATIONS TO THE WEST AND NORTH WILL HAVE SNOW FOR A
BIT LONGER...AND SLIGHTLY HIGHER AMOUNTS SHOULD BE FAVORED. OVERALL
1 TO 3 INCHES STILL LOOKS REASONABLE.
ON TOP OF THE SNOW THE STORM SYSTEM WILL BRING SOME BLUSTERY
CONDITIONS. TIGHTENING PRESSURE GRADIENT WILL RESULT IN NORTHWEST
WINDS OF 15 TO 25 MPH WITH GUSTS OF 30 TO 35 IN THE
OPEN/UNSHELTERED AREAS OF SOUTHEAST MN/NORTHEAST IA. THIS COULD
CAUSE SOME BLOWING OF THE FRESHLY FALLEN SNOW. THE PREVIOUS SNOW
COVER WILL BE HELD IN PLACE BY THE LIGHT GLAZING OF ICE FROM
YESTERDAY/S FREEZING DRIZZLE. LOW LEVEL COLD AIR ADVECTION WILL KEEP
TEMPERATURES STEADY...OR SLOWLY FALL. TODAY/S HIGH HAVE PROBABLY
ALREADY OCCURRED.
AS FOR THE WINTER WEATHER ADVISORY...WITH SNOW JUST MOVING IN...WILL
CONTINUE THE ADVISORY. THE NORTHERN PORTION OF THE ADVISORY MAY BE
ABLE TO BE CANCELLED BEFORE THE 6 PM EXPIRATION.
.LONG TERM...THURSDAY THROUGH SUNDAY
245 AM CST MON JAN 23 2012
MODELS POINT TO A MOSTLY ZONAL TO SOMEWHAT NORTHWEST UPPER LEVEL
FLOW THROUGH THE WEEKEND. BITS OF SHORTWAVE ENERGY WILL TRAVEL ALONG
THE FLOW...WITH DECENT AGREEMENT BETWEEN THE GFS AND EC WITH SLIDING
A TROUGH ACROSS THE UPPER MISSISSIPPI RIVER VALLEY WED NIGHT/THU.
THE BRUNT OF THE QPF STAYS NORTH OF THE FORECAST AREA
HOWEVER...ALTHOUGH A TIGHTENING PRESSURE GRADIENT WILL RESULT IN
SOME BLUSTERY CONDITIONS. OVERALL...THE PERIOD IS STILL TRENDING DRY
WITH TEMPS AT OR ABOVE THE SEASONABLE NORMALS.
&&
.AVIATION...THIS AFTERNOON THRU TUESDAY
1127 AM CST MON JAN 23 2012
LIGHT SNOW WILL DIMINISH AT THE TAFS SITES EARLY THIS AFTERNOON...
WITH CIGS/VSBYS LIFTING INTO THE MVFR RANGE AND VSBYS IMPROVING INTO
THE MVFR/VFR RANGE. BRISK NORTHWEST WINDS IN THE WAKE OF THE
DEPARTING LOW WILL CREATE SOME DRIFTING/BLOWING SNOW THRU THE
AFTERNOON HOURS AT SITES LIKE KRST. BIT LOWER STRATUS DECK OVER THE
EASTERN DAKOTAS/WESTERN MN WILL ROTATE ACROSS THE TAF SITES WITH
CIGS IN THE MVFR/IFR RANGE BY LATE EVENING AND OVERNIGHT AIDED BY
NOCTURNAL COOLING. WINDS WILL DIMINISH LATE THIS AFTERNOON AND THIS
EVENING AS THE LOW CONTINUES TO PULL AWAY AND THE SFC RIDGE AXIS
OVER THE DAKOTAS MOVES EAST. BIGGEST DILEMMA IS HOW QUICKLY WILL THE
LOWER CLOUDS/MVFR/IFR CIGS SCATTER/CLEAR OUT VERY LATE TONIGHT/TUE
MORNING. MODEL 925-850MB RH FIELDS WOULD HAVE THE CLOUDS OUT OF KRST
AROUND 10-11Z AND KLSE AROUND 15Z. GIVEN THE TIME OF YEAR AND
POSTION OF THE SFC-925MB RIDGE AXIS...THIS SEEMS A BIT OPTIMISTIC.
WENT WITH A SCT DECK AT 12Z KRST AND 16Z AT KLSE FOR NOW BUT AGAIN
THIS MAY BE ON THE OPTIMISTIC. LATER SHIFTS/CYCLES WILL BE ABLE TO
GET A BETTER ESTIMATE ON THE EASTWARD PROGRESS OF THE BACK EDGE OF
THE LOW CLOUDS IN THE DAKOTAS LATE THIS AFTERNOON/EVENING AS THE SFC
LOW CONTINUES TO LIFT INTO EASTERN ONTARIO.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1218 PM CST MON JAN 23 2012
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1129 AM CST MON JAN 23 2012
.AVIATION/18Z TAFS/...991 MILLIBAR SURFACE LOW IN NORTHERN LAKE
MICHIGAN CONTINUES TO PULL AWAY. WNW WINDS INCREASING WITH COLD
AIR ADVECTION. STILL SOME LINGERING LIGHT PRECIP...RAIN MIXING
WITH AND CHANGING TO LIGHT SNOW. IFR CEILINGS GRADUALLY TO GIVE
WAY TO MVFR CEILINGS. SHIELD OF LOW LELVEL CLOUDINESS EXTENDS FOR
TO THE WEST SO WILL BE A SLOW CLEARING TREND. PREFERRED THE MET
MOS TRENDS MORE SO THAN THE GFS IN THIS REGARD. ALSO LOW LEVEL RH
PROGS SUGGEST KEEPING A GOOD DEAL OF LOW CLOUDINESS INTO TUESDAY
MORNING. SURFACE HIGH BUILDS IN DURING THE AFTERNOON AND UPPER
FLOW BECOMES MORE ANTICYCLONIC...SO CONFIDENCE IN CLEARING
INCREASES HEADING TOWARDS THE AFTERNOON HOURS ON TUESDAY.
PC
&&
.PREV DISCUSSION... /ISSUED 242 AM CST MON JAN 23 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
NEGATIVE TILTED MID LEVEL/UPPER LEVEL TROUGH WILL MOVE ACROSS
WISCONSIN THIS MORNING BECOMING MORE OF A CLOSED LOW BY NOON...THEN
NORTH TOWARDS LAKE SUPERIOR THIS EVENING.
SURFACE LOW IS RATHER BROAD BUT THE CENTER SHOULD MOVE ACROSS
SOUTHEAST WISCONSIN THIS MORNING AND TO CENTRAL LAKE MICHIGAN BY
NOON...THEN NEAR LAKE HURON THIS EVENING. HIGHEST QPF OFF TO THE
SOUTHEAST AND EAST WITH SOME ELEVATED CAPE EARLY THIS MORNING
THICKNESS/BOUNDARY LAYER TEMPERATURES INDICATING MOST OF THE
PRECIPITATION LIQUID EXCEPT FOR A CHANGEOVER TO SNOW AROUND 6 AM
POSSIBLE WELL WEST OF MADISON. RUC SOUNDINGS PREFERRED OVER THE
COLDER NAM. THIS WOULD KEEP LIQUID AT MADISON UNTIL MID MORNING AND
OVER MILWAUKEE TOWARDS NOON.
MAIN CONCERN IS STILL WITH FREEZING RAIN POTENTIAL. SURFACE
TEMPERATURES ARE ALL ABOVE FREEZING EXCEPT IN AREAS TOWARDS THE
DELLS AND MARQUETTE COUNTY. OTHER PROBLEM IS WITH COLD ROAD
TEMPERATURES AND THE RAIN WASHING OFF THE RESIDUAL SALT...STILL SOME
SLIPPERY ROADS IN AREAS WITH TEMPERATURES IN THE MID 30S.
SOME DENSE FOG POTENTIAL EARLY THIS MORNING UNDER THE SURFACE LOW.
LIGHT ACCUMULATIONS OF SNOW EXPECTED WITH THE CHANGEOVER...UP TO AN
INCH. THIS MAINLY AS UPPER LOW MOVES ACROSS. TIGHT GRADIENT AROUND
THE LOW MAY GENERATE SOME PRETTY GUSTY WINDS...POTENTIALLY INTO THE
30-35 MPH RANGE LATER THIS AFTERNOON.
TUESDAY THROUGH SUNDAY...FORECAST CONFIDENCE...MEDIUM
FAIRLY QUIET WEATHER EXPECTED THROUGH THE REMAINDER OF THE WORK WEEK
AND INTO THE WEEKEND.
HIGH PRESSURE ON TUESDAY WILL BRING DECREASING CLOUDS WITH NEAR
NORMAL HIGH TEMPERATURES.
A PAIR OF WEAK WAVES TO ZIP THROUGH ZONAL FLOW WEDNESDAY AND
THURSDAY. NOT SEEING ENOUGH MOISTURE AND LIFT TO INCLUDE MENTION OF
POPS...THOUGH ONE OF THESE WAVES MAY SQUEEZE OUT A FEW FLURRIES.
ABOVE NORMAL TEMPS IN THE LOW TO MID 30S EXPECTED UNDER THE ZONAL
FLOW FOR MID WEEK.
ONE MORE DAY OF ABOVE NORMAL TEMPS FRIDAY WILL BE FOLLOWED BY
COLDER...BUT STILL NEAR NORMAL TEMPS FOR THE WEEKEND AS AN UPPER
TROUGH MOVES INTO THE GREAT LAKES. NOTHING IN THE MODELS AT THIS
TIME TO INCLUDE POPS FOR THE WEEKEND.
AVIATION/12Z TAFS/...WIDESPREAD LIFR CEILINGS/VSBYS WITH PLENTIFUL
LOW LEVEL MOISTURE AHEAD OF APPROACHING SURFACE LOW THAT SHOULD MOVE
ACROSS SOUTHEAST WISCONSIN THIS MORNING. ONCE LOW MOVES TO CENTRAL
LAKE MICHIGAN BY NOON...EXPECT COLD AIR ADVECTION TO GRADUALLY
CHANGE PRECIP OVER TO LIGHT SNOW. EXPECTING MINOR ACCUMULATIONS...AN
INCH OR LESS. WEST WINDS WILL BECOME RATHER GUSTY THIS AFTERNOON
WITH TIGHT GRADIENT AROUND STRONG DEPARTING LOW CENTER. CEILINGS
AND VSBYS WILL GRADUALLY RISE TO MVFR LATER THIS AFTERNOON AS THE
LOW PULLS AWAY. MVFR CIGS AND VFR VSBYS EXPECTED TONIGHT.
MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH MIDDAY TUESDAY
AS STRONG LOW PRESSURE REACHES CENTRAL LAKE MICHIGAN BY NOON. WINDS
WILL DIMINISH FOR A TIME UNDER THE LOW CENTER...BUT WILL INCREASE
AGAIN BEHIND A COLD FRONT EARLY THIS AFTERNOON AS WINDS BECOME
SOUTHWEST AND EVENTUALLY NORTHWEST. A FEW GALE GUSTS POSSIBLE....
ESPECIALLY LATE THIS AFTERNOON INTO THIS EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON CST TUESDAY FOR LMZ643>646.
DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR LMZ643-644.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
TUESDAY THROUGH SUNDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1127 AM CST MON JAN 23 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
245 AM CST MON JAN 23 2012
FORECAST CONCERNS FOCUS ON THE SNOW THIS MORNING.
LATEST WATERVAPOR IMAGERY DEPICTED AN UPPER LEVEL SHORTWAVE TROUGH
CHURNING ACROSS THE SOUTHERN PLAINS...WHILE AT THE SFC A LOW WAS
LOCATED OVER NORTHERN MO. 88-D RADAR IMAGERY SHOWED AREAS OF PCPN
SPREADING FROM THE DAKOTAS ACROSS MN/IA...AND ACROSS SOUTHERN WI AND
ILL. WHAT WAS FALLING WAS DEPENDENT ON SFC TEMPS AND WHETHER OR NOT
ANY ICE WAS IN THE CLOUD.
23.00Z ARE IN GOOD AGREEMENT WITH LIFTING THE TROUGH NORTHEAST
ACROSS THE REGION TODAY...AND OVER SOUTHEAST CANADA TONIGHT. THE
BULK OF THE ASSOCIATED QG CONVERGENCE WITH THE UPPER LEVEL FORCING
EXITS THE FORECAST AREA BY 18Z...AS DOES ANY ISENTROPIC UPGLIDE ON
THE 275-295 K SFCS. X-SECTIONS POINT TO SOME 2-D FRONTOGENETIC
FORCING...BUT THIS ALSO LIFTS TO THE NORTHEAST BY 18Z.
AS IT LOOKS NOW...THE BULK OF ANY ACCUMULATING PCPN SHOULD BE THIS
MORNING...WITH PERHAPS SOME LIGHT PCPN LINGERING INTO THE AFTERNOON
ACROSS NORTHERN AREAS. RUC13 BUFKIT SOUNDINGS SATURATE ENOUGH THAT
ICE IS INTRODUCED INTO THE CLOUD BY 3 AM...SO SNOW SHOULD BE THE
MAIN PCPN TYPE. MAIN MASS OF PCPN MOVING ACROSS THE REGION IS
ASSOCIATED WITH THE UPPER LEVEL TROUGH/QG CONVERGENCE. THE
DEFORMATION BAND NORTHWEST OF THE LOW HAS TWO AREAS...ONE FAIRLY
NARROW. THIS WAS IMPACTING WESTERN MN/WESTERN IA. THE MISH-MASH OF
DIFFERENT AREAS MAKES IT HARDER TO REFINE SNOW AMOUNTS FOR THIS
MORNING...BUT LOCATIONS TO THE WEST AND NORTH WILL HAVE SNOW FOR A
BIT LONGER...AND SLIGHTLY HIGHER AMOUNTS SHOULD BE FAVORED. OVERALL
1 TO 3 INCHES STILL LOOKS REASONABLE.
ON TOP OF THE SNOW THE STORM SYSTEM WILL BRING SOME BLUSTERY
CONDITIONS. TIGHTENING PRESSURE GRADIENT WILL RESULT IN NORTHWEST
WINDS OF 15 TO 25 MPH WITH GUSTS OF 30 TO 35 IN THE
OPEN/UNSHELTERED AREAS OF SOUTHEAST MN/NORTHEAST IA. THIS COULD
CAUSE SOME BLOWING OF THE FRESHLY FALLEN SNOW. THE PREVIOUS SNOW
COVER WILL BE HELD IN PLACE BY THE LIGHT GLAZING OF ICE FROM
YESTERDAY/S FREEZING DRIZZLE. LOW LEVEL COLD AIR ADVECTION WILL KEEP
TEMPERATURES STEADY...OR SLOWLY FALL. TODAY/S HIGH HAVE PROBABLY
ALREADY OCCURRED.
AS FOR THE WINTER WEATHER ADVISORY...WITH SNOW JUST MOVING IN...WILL
CONTINUE THE ADVISORY. THE NORTHERN PORTION OF THE ADVISORY MAY BE
ABLE TO BE CANCELLED BEFORE THE 6 PM EXPIRATION.
.LONG TERM...THURSDAY THROUGH SUNDAY
245 AM CST MON JAN 23 2012
MODELS POINT TO A MOSTLY ZONAL TO SOMEWHAT NORTHWEST UPPER LEVEL
FLOW THROUGH THE WEEKEND. BITS OF SHORTWAVE ENERGY WILL TRAVEL ALONG
THE FLOW...WITH DECENT AGREEMENT BETWEEN THE GFS AND EC WITH SLIDING
A TROUGH ACROSS THE UPPER MISSISSIPPI RIVER VALLEY WED NIGHT/THU.
THE BRUNT OF THE QPF STAYS NORTH OF THE FORECAST AREA
HOWEVER...ALTHOUGH A TIGHTENING PRESSURE GRADIENT WILL RESULT IN
SOME BLUSTERY CONDITIONS. OVERALL...THE PERIOD IS STILL TRENDING DRY
WITH TEMPS AT OR ABOVE THE SEASONABLE NORMALS.
&&
.AVIATION...THIS AFTERNOON THRU TUESDAY
1127 AM CST MON JAN 23 2012
LIGHT SNOW WILL DIMINISH AT THE TAFS SITES EARLY THIS AFTERNOON...
WITH CIGS/VSBYS LIFTING INTO THE MVFR RANGE AND VSBYS IMPROVING INTO
THE MVFR/VFR RANGE. BRISK NORTHWEST WINDS IN THE WAKE OF THE
DEPARTING LOW WILL CREATE SOME DRIFTING/BLOWING SNOW THRU THE
AFTERNOON HOURS AT SITES LIKE KRST. BIT LOWER STRATUS DECK OVER THE
EASTERN DAKOTAS/WESTERN MN WILL ROTATE ACROSS THE TAF SITES WITH
CIGS IN THE MVFR/IFR RANGE BY LATE EVENING AND OVERNIGHT AIDED BY
NOCTURNAL COOLING. WINDS WILL DIMINISH LATE THIS AFTERNOON AND THIS
EVENING AS THE LOW CONTINUES TO PULL AWAY AND THE SFC RIDGE AXIS
OVER THE DAKOTAS MOVES EAST. BIGGEST DILEMMA IS HOW QUICKLY WILL THE
LOWER CLOUDS/MVFR/IFR CIGS SCATTER/CLEAR OUT VERY LATE TONIGHT/TUE
MORNING. MODEL 925-850MB RH FIELDS WOULD HAVE THE CLOUDS OUT OF KRST
AROUND 10-11Z AND KLSE AROUND 15Z. GIVEN THE TIME OF YEAR AND
POSTION OF THE SFC-925MB RIDGE AXIS...THIS SEEMS A BIT OPTIMISTIC.
WENT WITH A SCT DECK AT 12Z KRST AND 16Z AT KLSE FOR NOW BUT AGAIN
THIS MAY BE ON THE OPTIMISTIC. LATER SHIFTS/CYCLES WILL BE ABLE TO
GET A BETTER ESTIMATE ON THE EASTWARD PROGRESS OF THE BACK EDGE OF
THE LOW CLOUDS IN THE DAKOTAS LATE THIS AFTERNOON/EVENING AS THE SFC
LOW CONTINUES TO LIFT INTO EASTERN ONTARIO.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
245 PM CST MON JAN 23 2012
WI...WINTER WEATHER ADVISORY UNTIL NOON CST FOR WIZ032>034-
041>044-053>055-061.
WINTER WEATHER ADVISORY UNTIL 6 PM CST FOR WIZ017-029.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST FOR MNZ079-086>088-
094>096.
IA...WINTER WEATHER ADVISORY UNTIL NOON CST FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1121 AM CST MON JAN 23 2012
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.UPDATE...BAND OF HEAVY SNOW SHIFTG THROUGH N-C WI NOW. IT APPEARS
2-3 INCHES HAS ALREADY FALLEN FM AUW NWD. LOOKS LIKE AREAS FROM
AUW NWD ARE HEADED TOWARD THE UPPER LIMITS OF THE SNOWFALL RANGES
WE HAVE IN GOING FCST. DON/T WANT TO OVERREACT THOUGH SINCE RADAR
SUGGESTS BEST SNOWS MOVG THROUGH NOW. NAM AND RUC BOTH SHOW VV/S
WEAKENING SUBSTANTIALLY BY MID-MORNING...WITH MODEST VALUES AT
BEST LINGERING NR THE UPPER MICHIGAN BORDER. THAT FITS WITH
COLDEST CLOUD TOPS LIFT THROUGH THAT AREA ON IR STLT NOW.
MAY NUDGE SNOWFALL TOTAL UP A BIT IN THE N. FARTHER S...IT/S
PROBABLY JUST A MATTER THAT WE/VE ALREADY RECEIVED MOST OF THE
SNOW WE ARE GOING TO GET. BEST OPTION THERE MAY BE TO REWORK FCST
TO CALL FOR LIMITED ADDITIONAL ACCUMULATIONS. PLAN TO SEND UPDATED
PRODUCT SUITE WITHIN ABOUT THE NEXT HALF HOUR.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 333 AM CST MON JAN 23 2012...
SYNOPSIS...WINTER WX ADVISORY WL REMAIN INTACT WITH THIS
ISSUANCE. MIXED PRECIPITATION CHANGING TO SNOW AND THEN ENDING
FROM SOUTHWEST TO NORTHEAST TODAY.
SPLIT FLOW WL DOMINATE THE CONUS FOR MUCH OF THE WEEK. BY NEXT
WEEKEND...RISING HEIGHTS OUT NR THE WEST COAST WL CAUSE THE
DOWNSTREAM FLOW TO CONSOLIDATE AGAIN...WITH BROAD TROF FORMING
OVER CEN/ERN NOAM.
MOST SIG PCPN EVENT WL BE WITH CYCLONE CROSSING THE RGN TDA...THEN
A PERIOD OF RELATIVELY QUIET WX EXPECTED AS THE FCST AREA IS
DOMINATED BY LOW-AMPLITUDE NRN STREAM THE REST OF THE WEEK. TEMPS
WL REMAIN ABV NORMAL MOST OF THE WK...THEN DROP BACK CLOSE TO
NORMAL AS BROAD UPR TROF DEVELOPS OVER THE FCST AREA NEXT WEEKEND.
SHORT TERM...TDA/TNGT/TUE. CYCLONE WL LIFT NEWD ACRS THE FCST
AREA THIS MORNING. DEEPENING MOISTURE...MID-LVL COOLING DUE TO
ASCENT...AND EVENTUALLY COLDER AIR WRAPPING ARND THE CYCLONE WL
RESULT IN DZ/FZDZ/RN CHANGING TO SN FM W TO E DURING THE DAY. THIS
WAS STARTING TO HAPPEN QUICKLY OVER WRN PARTS OF WI THIS MORNING.
SOUNDINGS CONSTRUCTED OFF RUC ANALYSES SUGGEST MUCH OF CENTRAL AND
N-C WL GO OVER TO SNOW ONCE BAND OF HEAVIER PCPN ARRIVES FROM THE
S. N-C WI AND PORTIONS OF NE WI WL NEED ADVISORY ALL DAY DUE TO
THE SNOW. NOT SURE SNOWFALLS WL JUSTIFY KEEPING ADVISORY GOING ALL
DAY OVER CENTRAL WI. BUT SNOW FALLING ON ICY ROADS WON/T BE
GOOD...SO TRAVEL CONDITIONS MAY REMAIN POOR. PLAN TO KEEP HEADLINE
INTACT WITH THE ISSUANCE AND JUST CANCEL EARLY IF/WHEN CONDITIONS
IMPROVE.
DENSE FOG COULD BE AN ISSUE IN THE E...ESP ALONG THE TRACKLINE OF
THE SFC LOW WHERE WINDS WL GO LGT FOR A TIME AS THE LOW CROSSES
THE AREA. BUT BAND OF HEAVIER PCPN THAT DEVELOPED DURING THE PAST
1-2 HRS WL WORK ACRS THIS AREA...HELPING TO MIX THE LOWER ATM.
SFC WINDS WERE ALSO LOSING THE SELY TRAJECTORY THAT WAS FEEDING
HIGHER DWPTS INTO THE AREA. BEST COURSE OF ACTION SEEM TO BE TO
GO WITH AREAS OF DENSE FOG IN THE GRIDS/ZONES...BUT FOREGO
ADVISORY SINCE IT DOESN/T APPEAR LOW VSBYS WL BE WIDESPREAD ENOUGH
TO WARRANT AN ADVISORY.
TRAJECTORIES LOOK FAVORABLE FOR SOME LAKE-EFFECT IN NORTH-CENTRAL
WI THIS AFTN INTO EARLY EVENING. LAKE SURFACE/AIR TEMPERATURE
DIFFERENCE SOMEWHAT MARGINAL...BUT PLENTY OF MOISTURE LINGERING FM
DEPARTING SYSTEM MAY OFFSET THAT. OTHER THAN THE LAKE-EFFECT...
PCPN SHOULD DIMINISH MOST AREAS BY EARLY EVENING.
CLDS LIKELY TO LINGER TNGT...WITH THE BEST CHC FOR BREAKS IN THE
TYPICAL NW-FLOW DOWNSLOPE AREA OVER THE NE.
HIGH TEMPS WL OCCUR EARLY TDA...FOLLOWED BY SLOWLY FALLING TEMPS.
BUT THE AIR BEHIND THE SYSTEM ISN/T REAL COLD...SO LINGERING
MOISTURE ON ROADWAYS SHOULD HAVE A CHC TO EVAPORATE BEFORE CAN
FREEZE. EDGED MINS UP A BIT TNGT...THEN WENT WITH BLEND OF BEST
PERFORMING GUID FOR MAXES TUE.
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY.
THE UPPER FLOW WILL BE TRANSITIONING OVER THE PERIOD FROM A FAST
ZONAL PATTERN...TO BUCKLED NORTHWEST FLOW. AS A RESULT...MILD
PACIFIC DOMINATED AIRMASSES THROUGH THE END OF THIS WEEK WILL RETURN
TO THE POLAR VARIETY. A COUPLE OF MINOR SYSTEMS TO DEAL WITH
THROUGH THE EXTENDED. SIMILAR TO LAST NIGHT PREFER THE GFS FOR THE
SHORTWAVE LATE WEDNESDAY NIGHT INTO THURSDAY WITH THE FAST FLOW IN
PLACE. THEREAFTER...A CLIPPER SYSTEM WILL ARRIVE ON SATURDAY WHICH
WILL BE THE LEADING EDGE OF ARCTIC AIR. BOTH THE GFS AND ECMWF
HANDLE THIS FEATURE COMPARABLY...SO WILL BLEND THE TWO SOLUTIONS.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...WEAK SHEARED SHORTWAVE
WILL BE CROSSING THE REGION LATE TUESDAY NIGHT INTO EARLY WEDNESDAY
MORNING. MID AND HIGH CLOUDS WILL BE ON THE INCREASE TUESDAY NIGHT
AHEAD OF THE WAVE...BUT LOW LEVELS STRUGGLE TO SATURATE. SUPPOSE
THERE COULD BE A FLURRY OR TWO OUT OF THE MID-DECK BUT THATS MORE OF
A SHORT TERM CONCERN SO WILL LEAVE THE FORECAST DRY. SKIES WILL BE
CLEARING ON WEDNESDAY AS THE FIRST SHORTWAVE DEPARTS. HIGHS WILL BE
MILD WITHIN A PACIFIC AIRMASS WITH READINGS AROUND THE FREEZING
MARK. CLOUDS WILL BE ON THE INCREASE AGAIN WEDNESDAY NIGHT AHEAD OF
A MORE DYNAMIC SHORTWAVE. NOT SEEING THE GOOD MID-LEVEL LAPSE RATES
LIKE LAST NIGHT...BUT MID AND UPPER FORCING IS DECENT. STILL
LOOKING AT DRY WEDGES HOWEVER IN THE LOW AND MID-LEVELS WITH
MOISTURE PROFILES FAILING TO SATURATE. WILL AGAIN TREAT THIS AS A
SHORT TERM CONCERN AND REMOVE POPS.
REST OF THE FORECAST...THE SHORTWAVE TROUGH WILL FINISH CROSSING THE
REGION THURSDAY MORNING AND WILL AGAIN REMOVE THE SLIGHT CHANCE OF
PRECIP. SHOULD SEE SOME SUN MOVE IN FOR THE AFTERNOON WITH TEMPS
SLIGHTLY ABOVE FREEZING. NORTHWEST FLOW ALOFT WILL BE STRENGTHENING
THURSDAY NIGHT INTO FRIDAY...WHEN WILL HAVE WEAK COLD ADVECTION AND
BREEZY CONDITIONS OVER THE PERIOD...BUT NO PRECIP THREAT OF
SIGNIFICANCE. RATHER STRONG SHORTWAVE WILL BE MOVING ACROSS THE
REGION FRIDAY NIGHT...WHICH WILL BE THE LEADING EDGE OF AN ARCTIC
AIRMASS. TEMPERATURES WILL FALL BACK TO OR BELOW NORMAL WHILE WINDS
WILL BE PRETTY BRISK. CAN ENVISION OCCASIONAL SNOW FLURRIES OR
LIGHT SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY AS THE UPPER TROUGH
SWINGS OVERHEAD. CURRENT FORECAST IS DRY...BUT WILL JUST MENTION TO
LATER SHIFTS. COLD AND DRY CONDITIONS ON SUNDAY...AND POSSIBLY SOME
LIGHT SNOW ON MONDAY AS ANOTHER CLIPPER SYSTEM MOVES THROUGH THE
REGION.
&&
.AVIATION...WIDESPREAD IFR/MVFR CONDITIONS TO CONTINUE ACROSS NE
WI THIS AFTERNOON AS THE STORM RESPONSIBLE FOR THE FREEZING DRZL
LAST NGT AND SNOW THIS MORNING BEGINS TO PULL NE INTO CANADA. THE
HEAVIEST SNOWS HAVE PULLED AWAY...BUT EXPECT LGT SNOW OR FLURRIES
TO LINGER INTO THE EVENING HOURS. LOW-LVL MSTR TO BE SLOW TO EXIT
THE RGN...THUS A GENERAL MVFR CIG CONDITION TO CONT OVRNGT. W-NW
WINDS COULD CREATE DOWNSLOPING AND PERHAPS BREAK SOME OF THESE
CLOUDS UP OVER THE GRB AND ATW TAF SITES LATER TNGT. A RDG OF HI
PRES BUILDING INTO WI ON MONDAY SHOULD PROVIDE ENUF DRY AIR TO
BREAK UP THE CLOUDS TOWARD THE MIDDAY HOUR WITH VFR CONDITIONS
RETURNING FOR MON AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ005-
010>013-018>021-030-031-035>037-045.
&&
$$
AK