Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 01/14/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1100 AM MST THU JAN 12 2012
.UPDATE...FEW CHANGES NEEDED FOR THE SHORT TERM. ANY BLOWING SNOW
THAT OCCURS SHOULD BE VERY LOCALIZED AND CAN BE HANDLED BY
NOWCASTS. SO WILL NOT EXTEND THE PATCHY BLOWING SNOW GRID INTO
THIS AFTERNOON. MODELS CONTINUE TO SHOW A WEAKENING GRADIENT
ACROSS THE PLAINS THIS EVENING...WOULD EXPECT A DECREASE IN WINDS
AS A RESULT. WATER VAPOR LOOPS SHOW SOME SORT OF A WEAK WAVE
MOVING INTO WESTERN WYOMING...WITH MAINLY HIGH LEVEL MOISTURE.
MODELS DON`T SEEM TO PICK UP THIS FEATURE...WILL NEED TO MONITOR
FOR ANY TYPE OF WIND INCREASE AS THIS FEATURE MOVES AWAY FROM THE
AREA.
&&
.AVIATION...DELAYED THE SHIFT TO NORTHWEST AT AREA AIRPORTS TIL
20Z...AS SHOWN BY RUC. NAM AND HRRR KEEP THE SOUTHWEST WINDS
PREVAILING. NOT SURE ABOUT THE GFS AND THE WEAK EASTERLIES.
WILL MONITOR FOR ANY DEVELOPMENT OF A DENVER CYCLONE.
OTHERWISE...TAF TRENDS SEEM REASONABLE.
&&
.PREV DISCUSSION... /ISSUED 251 AM MST THU JAN 12 2012/
SHORT TERM...NW FLOW ALOFT WILL BE OVER THE AREA TODAY. GUSTY
WINDS WILL BE POSSIBLE IN THE MTNS AND ALONG THE FOOTHILLS THRU THE
MORNING HOURS WITH A FEW AREAS OF BLOWING SNOW. OVER NERN CO GUSTY
NWLY WINDS WILL ALSO OCCUR WHICH WILL LINGER THROUGH THE AFTN HOURS
BUT SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA. AS FOR HIGHS WILL
KEEP READINGS MAINLY IN THE 35 TO 40 DEGREE RANGE OVER NERN CO.
FOR TONIGHT A WEAK UPPER LEVEL TROUGH IN NW FLOW WILL MOVE ACROSS
THE AREA HOWEVER CROSS-SECTIONS SHOW MOISTURE CONFINED TO THE MID
AND UPPER LEVELS. THUS WILL SEE AN INCREASE IN CLOUDS WITH ONLY A
FEW FLURRIES OVER THE HIGHER MTN PEAKS. LATE TONIGHT AS SUBSIDENCE
DEVELOPS BEHIND PASSAGE OF WEAK UPPER LEVEL TROUGH WINDS MAY
INCREASE IN AND NR THE FOOTHILLS HOWEVER SPEEDS SHOULD REMAIN BLO
WARNING CRITERIA.
LONG TERM...MODELS HAVE STRONG NORTHERLY FLOW ALOFT FOR THE
FORECAST AREA ON FRIDAY...WITH AN UPPER RIDGE TO OUR WEST.
DECREASING NORTHWESTERLY FLOW ALOFT IS PROGGED FOR FRIDAY NIGHT
THROUGH SATURDAY. BY SATURDAY NIGHT...WEAK ZONAL FLOW ALOFT IS
PROGGED. THE QG VERTICAL VELOCITY FIELDS HAVE WEAK DOWNWARD MOTION
PROGGED FOR THE CWA THROUGH SATURDAY NIGHT. THE BOUNDARY LAYER FLOW
LOOKS TO BE A MIX OF THE NORMAL DIURNAL PATTERN COUPLED WITH
DOWNSLOPING WITH TROUGHING EAST OF THE MOUNTAINS THROUGH THE
PERIOD. FOR MOISTURE...THERE IS A BIT IN THE MID AND UPPER LEVELS
THROUGH THE PERIOD. THE IS NO MEASURABLE PRECIPITATION ON THE QPF
FIELDS THROUGH THE PERIOD. NO POPS. CROSS SECTIONS SHOW A BIT OF
MOUNTAINS WAVE SET UP FRIDAY AFTERNOON AND NIGHT. HOWEVER...IT IS
NOT SIGNIFICANT. FOR TEMPERATURES...FRIDAY`S HIGHS ARE 2-5 C WARMER
THAN TODAY`S. SATURDAY`S WARM-UP ANOTHER 2-4 C. WILL UNDERCUT MOS
GUIDANCE NUMBERS...ESPECIALLY IN THE AREAS WHERE THERE IS SNOW ON
THE GROUND. FOR THE LATER DAYS...SUNDAY THROUGH WEDNESDAY...ZONAL
FLOW GIVES WAY TO SOUTHWESTERLY FLOW ALOFT ON SUNDAY AND SUNDAY
NIGHT. THE ECMWF AND GFS BOTH SHOW A BROAD UPPER TROUGH TO MOVE
INTO COLORADO LATER MONDAY AND MONDAY NIGHT. BOTH HAVE A COLD FRONT
AND UPSLOPE FOR THE PLAINS AND FOOTHILLS MONDAY AFTERNOON AND
EVENING. IT IS A QUICK SHOT. FOR TUESDAY AND WEDNESDAY...
NORTHWESTERLY FLOW ALOFT IS PROGGED...AND THERE IS MOISTURE WITH
IT. PERHAPS OUR MOUNTAINS WILL SEE SOME SNOW. WILL LEAVE THE
EXTENDED GFE GRIDS PRETTY MUCH ALONE.
AVIATION...VFR THRU TONIGHT. WILL KEEP WINDS SSW THRU THE MORNING
HOURS AROUND 10 KTS. BY AFTN HRRR KEEPS WINDS MAINLY WSW WHILE THE
RUC HAS THEM SHIFTING TO MORE OF A WNW DIRECTION WITH SPEEDS AROUND
10 KTS. FOR NOW WILL TREND TOWARDS A WNW DIRECTON. BY EARLY
EVENING WINDS WILL GRADUALLY BECOME MORE WSW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER CO
251 AM MST THU JAN 12 2012
.SHORT TERM...NW FLOW ALOFT WILL BE OVER THE AREA TODAY. GUSTY
WINDS WILL BE POSSIBLE IN THE MTNS AND ALONG THE FOOTHILLS THRU THE
MORNING HOURS WITH A FEW AREAS OF BLOWING SNOW. OVER NERN CO GUSTY
NWLY WINDS WILL ALSO OCCUR WHICH WILL LINGER THROUGH THE AFTN HOURS
BUT SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA. AS FOR HIGHS WILL
KEEP READINGS MAINLY IN THE 35 TO 40 DEGREE RANGE OVER NERN CO.
FOR TONIGHT A WEAK UPPER LEVEL TROUGH IN NW FLOW WILL MOVE ACROSS
THE AREA HOWEVER CROSS-SECTIONS SHOW MOISTURE CONFINED TO THE MID
AND UPPER LEVELS. THUS WILL SEE AN INCREASE IN CLOUDS WITH ONLY A
FEW FLURRIES OVER THE HIGHER MTN PEAKS. LATE TONIGHT AS SUBSIDENCE
DEVELOPS BEHIND PASSAGE OF WEAK UPPER LEVEL TROUGH WINDS MAY
INCREASE IN AND NR THE FOOTHILLS HOWEVER SPEEDS SHOULD REMAIN BLO
WARNING CRITERIA.
.LONG TERM...MODELS HAVE STRONG NORTHERLY FLOW ALOFT FOR THE
FORECAST AREA ON FRIDAY...WITH AN UPPER RIDGE TO OUR WEST.
DECREASING NORTHWESTERLY FLOW ALOFT IS PROGGED FOR FRIDAY NIGHT
THROUGH SATURDAY. BY SATURDAY NIGHT...WEAK ZONAL FLOW ALOFT IS
PROGGED. THE QG VERTICAL VELOCITY FIELDS HAVE WEAK DOWNWARD MOTION
PROGGED FOR THE CWA THROUGH SATURDAY NIGHT. THE BOUNDARY LAYER FLOW
LOOKS TO BE A MIX OF THE NORMAL DIURNAL PATTERN COUPLED WITH
DOWNSLOPING WITH TROUGHING EAST OF THE MOUNTAINS THROUGH THE
PERIOD. FOR MOISTURE...THERE IS A BIT IN THE MID AND UPPER LEVELS
THROUGH THE PERIOD. THE IS NO MEASURABLE PRECIPITATION ON THE QPF
FIELDS THROUGH THE PERIOD. NO POPS. CROSS SECTIONS SHOW A BIT OF
MOUNTAINS WAVE SET UP FRIDAY AFTERNOON AND NIGHT. HOWEVER...IT IS
NOT SIGNIFICANT. FOR TEMPERATURES...FRIDAY`S HIGHS ARE 2-5 C WARMER
THAN TODAY`S. SATURDAY`S WARM-UP ANOTHER 2-4 C. WILL UNDERCUT MOS
GUIDANCE NUMBERS...ESPECIALLY IN THE AREAS WHERE THERE IS SNOW ON
THE GROUND. FOR THE LATER DAYS...SUNDAY THROUGH WEDNESDAY...ZONAL
FLOW GIVES WAY TO SOUTHWESTERLY FLOW ALOFT ON SUNDAY AND SUNDAY
NIGHT. THE ECMWF AND GFS BOTH SHOW A BROAD UPPER TROUGH TO MOVE
INTO COLORADO LATER MONDAY AND MONDAY NIGHT. BOTH HAVE A COLD FRONT
AND UPSLOPE FOR THE PLAINS AND FOOTHILLS MONDAY AFTERNOON AND
EVENING. IT IS A QUICK SHOT. FOR TUESDAY AND WEDNESDAY...
NORTHWESTERLY FLOW ALOFT IS PROGGED...AND THERE IS MOISTURE WITH
IT. PERHAPS OUR MOUNTAINS WILL SEE SOME SNOW. WILL LEAVE THE
EXTENDED GFE GRIDS PRETTY MUCH ALONE.
&&
.AVIATION...VFR THRU TONIGHT. WILL KEEP WINDS SSW THRU THE MORNING
HOURS AROUND 10 KTS. BY AFTN HRRR KEEPS WINDS MAINLY WSW WHILE THE
RUC HAS THEM SHIFTING TO MORE OF A WNW DIRECTION WITH SPEEDS AROUND
10 KTS. FOR NOW WILL TREND TOWARDS A WNW DIRECTON. BY EARLY
EVENING WINDS WILL GRADUALLY BECOME MORE WSW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
RPK/RJK
AREA FORECAST DISCUSSION
NWS ALBANY NY
950 PM EST FRI JAN 13 2012
.SYNOPSIS...
LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES
INTO THE CANADIAN MARITIMES TONIGHT. BLUSTERY AND COLD CONDITIONS
WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS AND
FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS DAYBREAK.
ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN ONTARIO LATE
SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT FRIGID TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WINTER STORM WARNING AND SOME OF THE WINTER WEATHER ADVISORIES
HAVE BEEN DROPPED.
SNOW HAS DIMINISHED GREATLY ACROSS THE REGION AS THE INVERSIONS
AND MOISTURE LAYER HAVE BECOME MORE SHALLOW. LAKE EFFECT BAND
NOSING INTO HERKIMER AND HAMILTON COUNTIES RELATIVELY STABLE AND
SHOULD CONTINUE TO PRODUCE LIGHT TO MODERATE SNOW...LOCALLY HEAVY
SNOW THROUGH THE EARLY MORNING HOURS. HAVE DROPPED ALL HEADLINES
EXCEPT FOR THE WINTER WEATHER ADVISORY IN THE WESTERN MOHAWK
VALLEY AND SOUTHERN ADIRONDACKS...WHERE IT HAS BEEN EXTENDED UNTIL
6 AM. THE LAKE EFFCT BAND MAY BREAK UP BEFORE THEN BUT IT CAN BE
CANCELLED EARLY IF NECESSARY. THERE MAY BE ONLY AN INCH OR TWO
ADDITIONAL ACCUMULATION IN THOSE AREAS...WITH STORM TOTALS OF 4
TO UP TO AROUND 8 INCHES LOCALLY.
WITH THE CLOUD COVER AND THE WINDS STAYING UP...TEMPERATURES ARE
NOT FALLING MUCH...BUT UPSTREAM TEMPERATURES SHOULD ADVECT INTO
OUR REGION BY DAYBREAK. SO...LOW TEMPERATURES SEEM TO BE IN THE
BALLPARK.
PREV AFD BELOW...
WIND ADVISORY CANCELLED AS WINDS HAVE DIMINISHED.
SOME OF THE SNOW IN THE WESTERN MOHAWK VALLEY...SOUTHERN
ADIRONDACKS...SCHOHARIE VALLEY AND CATSKILLS HAS DIMINISHED. AS
THE MEAN FLOW TURNS MORE WEST AND WEST NORTHWEST...SOME LAKE
EFFECT SNOW COULD NOSE BACK INTO THE WESTERN MOHAWK VALLEY AND
SOUTHERN ADIRONDACKS. SO...WINTER WEATHER ADVISORY WILL CONTINUE
FOR THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...BUT SNOW
CHANCES WILL BE REDUCED IN THE SCHOHARIE VALLEY AND CATSKILLS.
SNOW STILL AFFECTING THE SOUHTERN BERKSHIRES AND SOUTHERN VT SO
WINTER STORM WARNINGS WILL CONTINUE THERE. TEMPERATURES HAVE
FALLEN A BIT MORE RAPIDLY THAN WHAT WAS FORECASTED FOR THE CURRENT
TIME...BUT OVERALL LOW TEMPERATURES FOR LATER TONIGHT SHOULD BE IN
THE BALL PARK. 00Z DATA AND RADAR TRENDS WILL BE CHECKED FOR MORE
CHANGES LATER THIS EVENING.
PREV AFD BELOW...
AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF
SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG
THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST
RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY
AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN
BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER
STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE
UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR
RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS
OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE
INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA
COUNTIES TO 4-8" TOO.
PREVIOUS NEAR TERM...
AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE
POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN
IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW
ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC
LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED
OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE
OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES.
THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW
HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK
VALLEY.
THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL
BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A
REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF
THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A
CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY
ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID
LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE
UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR
WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND
HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z-
03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST
NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS.
THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN
HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL
CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC
ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED
THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK
VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS
EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE
CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY
TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER
CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE.
LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE
INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH
THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE
TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF
ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE
A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW
SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE
WILL HAVE TO MONITOR IF THIS MATERIALIZES.
IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35
KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM
KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO
35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE
CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE
LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC
TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP
THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE
SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS
AROUND 35 MPH.
A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION
BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF
SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH.
LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE
ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM
KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN
MTNS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS
THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST.
THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING
CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND
FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG
SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY
FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF
THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN
CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES
OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX
TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE
SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S
NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE
DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY
WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO
NORTH AND WEST OF THE CAPITAL REGION.
SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH
THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY
LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN
EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION
IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS
IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND
EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN
THE SRN DACKS.
SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW
ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL
WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT
SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE
START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS
DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF
A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS
WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK
VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS
NORTH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE
ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE
IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE
TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST
INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST
TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW
WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS
AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY.
THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A
NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH
CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE
MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE
LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT
THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE
OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING
THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH
WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A
WINTRY MIX...DEPENDING ON ELEVATION.
THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE
NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE
SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED
BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY
INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH
DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE
UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO
CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS.
NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD
OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE
FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
SNOW SHOWERS CONTINUE TO AFFECT EXTREME EASTERN NY AND ADJACENT
WESTERN NEW ENGLAND AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH
THE REGION OVERNIGHT/EARLY SATURDAY MORNING. SNOW SHOWERS COULD
AFFECT KGFL AND KALB...HAVE KEPT VCSH THROUGH SATURDAY MORNING.
WITHIN MODERATE TO HEAVY SHSN...COULD SEE MVFR CONDITIONS BUT
EXPECT AREAS OF MODERATE TO HEAVY PRECIP OVER THE TERRAIN DUE TO
OROGRAPHIC LIFT. MOST MODEL GUIDANCE INDICATES VFR CONDITIONS
THROUGH THE NEXT 24 HOURS AT ALL TERMINALS...BUT SCT025 CLOUDS
COULD FILTER INTO THE VALLEYS FROM LAKE EFFECT DEVELOPMENT.
SNOW SHOWERS ON SATURDAY WILL MAINLY BE LAKE EFFECT...WITH SFC
HIGH PRESSURE BUILDING INTO THE REGION...SO DON/T EXPECT MUCH OF
ANYTHING TO REACH THE HUDSON VALLEY. VFR CONDITIONS WILL PERSIST
WITH CLOUD COVER DECREASING THROUGHOUT THE DAY.
WINDS WILL CONTINUE OUT OF THE SW AT 10-15 KTS WITH GUSTS 15-25
KTS OVERNIGHT. SATURDAY MORNING...THE SFC LOW AND COLD FRONT WILL
CONTINUE TO MOVE EASTWARD OUT OF THE AREA...AND WIND SPEEDS WILL
GRADUALLY DECREASE OUT OF THE NW TO 7-12 KTS WITH GUSTS OF 20 KTS
OR LESS BY SATURDAY LATE AFTERNOON/EARLY EVENING.
OUTLOOK...
SAT-MON...VFR...NO SIG WX.
MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX.
WED...VFR...SLGT CHC -SHSN.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE
NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO
THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER
THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL
BY TUESDAY.
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...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 6 AM EST SATURDAY FOR NYZ032-033-
038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
713 PM EST FRI JAN 13 2012
.SYNOPSIS...
LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES
INTO THE CANADIAN MARITIMES TONIGHT. BLUSTERY AND COLD CONDITIONS
WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS AND
FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS DAYBREAK.
ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN ONTARIO LATE
SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT FRIGID TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WIND ADVISORY CANCELLED AS WINDS HAVE DIMINISHED.
SOME OF THE SNOW IN THE WESTERN MOHAWK VALLEY...SOUTHERN
ADIRONDACKS...SCHOHARIE VALLEY AND CATSKILLS HAS DIMINISHED. AS
THE MEAN FLOW TURNS MORE WEST AND WEST NORTHWEST...SOME LAKE
EFFECT SNOW COULD NOSE BACK INTO THE WESTERN MOHAWK VALLEY AND
SOUTHERN ADIRONDACKS. SO...WINTER WEATHER ADVISORY WILL CONTINUE
FOR THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...BUT SNOW
CHANCES WILL BE REDUCED IN THE SCHOHARIE VALLEY AND CATSKILLS.
SNOW STILL AFFECTING THE SOUHTERN BERKSHIRES AND SOUTHERN VT SO
WINTER STORM WARNINGS WILL CONTINUE THERE. TEMPERATURES HAVE
FALLEN A BIT MORE RAPIDLY THAN WHAT WAS FORECASTED FOR THE CURRENT
TIME...BUT OVERALL LOW TEMPERATURES FOR LATER TONIGHT SHOULD BE IN
THE BALL PARK. 00Z DATA AND RADAR TRENDS WILL BE CHECKED FOR MORE
CHANGES LATER THIS EVENING.
PREV AFD BELOW...
AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF
SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG
THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST
RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY
AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN
BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER
STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE
UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR
RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS
OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE
INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA
COUNTIES TO 4-8" TOO.
PREVIOUS NEAR TERM...
AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE
POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN
IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW
ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC
LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED
OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE
OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES.
THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW
HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK
VALLEY.
THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL
BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A
REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF
THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A
CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY
ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID
LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE
UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR
WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND
HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z-
03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST
NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS.
THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN
HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL
CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC
ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED
THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK
VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS
EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE
CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY
TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER
CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE.
LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE
INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH
THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE
TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF
ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE
A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW
SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE
WILL HAVE TO MONITOR IF THIS MATERIALIZES.
IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35
KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM
KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO
35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE
CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE
LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC
TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP
THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE
SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS
AROUND 35 MPH.
A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION
BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF
SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH.
LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE
ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM
KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN
MTNS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS
THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST.
THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING
CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND
FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG
SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY
FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF
THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN
CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES
OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX
TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE
SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S
NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE
DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY
WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO
NORTH AND WEST OF THE CAPITAL REGION.
SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH
THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY
LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN
EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION
IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS
IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND
EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN
THE SRN DACKS.
SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW
ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL
WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT
SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE
START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS
DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF
A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS
WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK
VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS
NORTH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE
ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE
IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE
TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST
INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST
TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW
WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS
AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY.
THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A
NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH
CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE
MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE
LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT
THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE
OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING
THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH
WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A
WINTRY MIX...DEPENDING ON ELEVATION.
THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE
NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE
SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED
BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY
INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH
DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE
UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO
CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS.
NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD
OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE
FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
SNOW SHOWERS CONTINUE TO AFFECT EXTREME EASTERN NY AND ADJACENT
WESTERN NEW ENGLAND AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH
THE REGION OVERNIGHT/EARLY SATURDAY MORNING. SNOW SHOWERS COULD
AFFECT KGFL AND KALB...HAVE KEPT VCSH THROUGH SATURDAY MORNING.
WITHIN MODERATE TO HEAVY SHSN...COULD SEE MVFR CONDITIONS BUT
EXPECT AREAS OF MODERATE TO HEAVY PRECIP OVER THE TERRAIN DUE TO
OROGRAPHIC LIFT. MOST MODEL GUIDANCE INDICATES VFR CONDITIONS
THROUGH THE NEXT 24 HOURS AT ALL TERMINALS...BUT SCT025 CLOUDS
COULD FILTER INTO THE VALLEYS FROM LAKE EFFECT DEVELOPMENT.
SNOW SHOWERS ON SATURDAY WILL MAINLY BE LAKE EFFECT...WITH SFC
HIGH PRESSURE BUILDING INTO THE REGION...SO DON/T EXPECT MUCH OF
ANYTHING TO REACH THE HUDSON VALLEY. VFR CONDITIONS WILL PERSIST
WITH CLOUD COVER DECREASING THROUGHOUT THE DAY.
WINDS WILL CONTINUE OUT OF THE SW AT 10-15 KTS WITH GUSTS 15-25
KTS OVERNIGHT. SATURDAY MORNING...THE SFC LOW AND COLD FRONT WILL
CONTINUE TO MOVE EASTWARD OUT OF THE AREA...AND WIND SPEEDS WILL
GRADUALLY DECREASE OUT OF THE NW TO 7-12 KTS WITH GUSTS OF 20 KTS
OR LESS BY SATURDAY LATE AFTERNOON/EARLY EVENING.
OUTLOOK...
SAT-MON...VFR...NO SIG WX.
MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX.
WED...VFR...SLGT CHC -SHSN.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE
NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO
THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER
THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL
BY TUESDAY.
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...NONE.
NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ032-
033-038-042-054-061.
MA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ025.
WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MAZ001.
VT...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VTZ013-014.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
AVIATION...KGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
702 PM EST FRI JAN 13 2012
.SYNOPSIS...
LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES
INTO THE CANADIAN MARITIMES TONIGHT. BLUSTERY AND COLD CONDITIONS
WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS AND
FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS DAYBREAK.
ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN ONTARIO LATE
SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT FRIGID TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF
SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG
THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST
RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY
AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN
BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER
STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE
UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR
RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS
OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE
INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA
COUNTIES TO 4-8" TOO.
PREVIOUS NEAR TERM...
AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE
POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN
IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW
ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC
LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED
OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE
OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES.
THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW
HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK
VALLEY.
THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL
BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A
REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF
THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A
CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY
ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID
LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE
UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR
WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND
HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z-
03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST
NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS.
THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN
HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL
CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC
ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED
THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK
VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS
EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE
CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY
TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER
CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE.
LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE
INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH
THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE
TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF
ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE
A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW
SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE
WILL HAVE TO MONITOR IF THIS MATERIALIZES.
IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35
KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM
KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO
35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE
CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE
LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC
TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP
THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE
SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS
AROUND 35 MPH.
A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION
BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF
SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH.
LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE
ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM
KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN
MTNS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS
THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST.
THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING
CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND
FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG
SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY
FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF
THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN
CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES
OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX
TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE
SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S
NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE
DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY
WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO
NORTH AND WEST OF THE CAPITAL REGION.
SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH
THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY
LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN
EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION
IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS
IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND
EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN
THE SRN DACKS.
SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW
ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL
WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT
SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE
START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS
DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF
A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS
WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK
VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS
NORTH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE
ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE
IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE
TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST
INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST
TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW
WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS
AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY.
THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A
NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH
CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE
MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE
LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT
THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE
OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING
THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH
WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A
WINTRY MIX...DEPENDING ON ELEVATION.
THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE
NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE
SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED
BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY
INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH
DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE
UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO
CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS.
NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD
OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE
FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
SNOW SHOWERS CONTINUE TO AFFECT EXTREME EASTERN NY AND ADJACENT
WESTERN NEW ENGLAND AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH
THE REGION OVERNIGHT/EARLY SATURDAY MORNING. SNOW SHOWERS COULD
AFFECT KGFL AND KALB...HAVE KEPT VCSH THROUGH SATURDAY MORNING.
WITHIN MODERATE TO HEAVY SHSN...COULD SEE MVFR CONDITIONS BUT
EXPECT AREAS OF MODERATE TO HEAVY PRECIP OVER THE TERRAIN DUE TO
OROGRAPHIC LIFT. MOST MODEL GUIDANCE INDICATES VFR CONDITIONS
THROUGH THE NEXT 24 HOURS AT ALL TERMINALS...BUT SCT025 CLOUDS
COULD FILTER INTO THE VALLEYS FROM LAKE EFFECT DEVELOPMENT.
SNOW SHOWERS ON SATURDAY WILL MAINLY BE LAKE EFFECT...WITH SFC
HIGH PRESSURE BUILDING INTO THE REGION...SO DON/T EXPECT MUCH OF
ANYTHING TO REACH THE HUDSON VALLEY. VFR CONDITIONS WILL PERSIST
WITH CLOUD COVER DECREASING THROUGHOUT THE DAY.
WINDS WILL CONTINUE OUT OF THE SW AT 10-15 KTS WITH GUSTS 15-25
KTS OVERNIGHT. SATURDAY MORNING...THE SFC LOW AND COLD FRONT WILL
CONTINUE TO MOVE EASTWARD OUT OF THE AREA...AND WIND SPEEDS WILL
GRADUALLY DECREASE OUT OF THE NW TO 7-12 KTS WITH GUSTS OF 20 KTS
OR LESS BY SATURDAY LATE AFTERNOON/EARLY EVENING.
OUTLOOK...
SAT-MON...VFR...NO SIG WX.
MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX.
WED...VFR...SLGT CHC -SHSN.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE
NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO
THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER
THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL
BY TUESDAY.
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...NONE.
NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ032-
033-038-042-054-061.
MA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ025.
WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MAZ001.
VT...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VTZ013-014.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...KGM
AVIATION...KGM
HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS NEW YORK NY
105 PM EST THU JAN 12 2012
.SYNOPSIS...
A STORM SYSTEM FROM THE OHIO VALLEY TO THE SOUTHERN NEW ENGLAND
COAST WILL MOVE SLOWLY TO THE NORTH AND EAST THROUGH FRIDAY. A
STRONG COLD FRONT WILL MOVE ACROSS THE REGION EARLY FRIDAY
MORNING. HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING LOW THROUGH
THE WEEKEND. HIGH PRESSURE REMAINS INTO THE BEGINNING OF THE WEEK.
ANOTHER COLD FRONT MOVES THROUGH THE AREA TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
GREATEST PRESSURE FALLS WERE JUST OFF THE SE NEW ENGLAND COAST
LATE THIS MORNING. THIS WOULD SUPPORT THE COASTAL LOW TO THE
SOUTH OF LI TAKING A TRACK TO THE E/SE OF THE TRI-STATE AREA.
12Z NAM AND RUC SUPPORT SUCH A TRACK. THIS WILL IN PART PRODUCE
SOMEWHAT COOLER HIGHS TODAY...ESPECIALLY ACROSS THE INTERIOR...BUT
ALSO KEEP THE WINDS IN A MORE NORTHERLY DIRECTION. IN ADDITION...A
STRONG NE FLOW CONTINUES ACROSS COASTAL LOCATIONS THIS MORNING WITH
GUSTS UP TO 30 MPH. THE GRADIENT WILL SLACKEN BY THIS AFTERNOON AS
THE LOW TRACKS TO THE NE OF THE AREA. MORE IMPORTANTLY...THIS MAY
EXACERBATE COASTAL FLOODING ACROSS LI SOUND THIS AFTERNOON. REFER
TO THE COASTAL FLOOD SECTION BELOW.
AS FOR THE RAIN AND EMBEDDED THUNDERSTORMS...THE MAIN AREA ACROSS
EASTERN CT AND EASTERN LI WILL LIFT TO THE NE AND CLEAR THE AREA
BY NOONTIME. THERE MAY BE PATCHES OF LIGHT RAIN THROUGH THE
AFTERNOON WITH WEAK LIFT AND MOISTURE IN PLACE.
DUE TO THE LOW TRACK...HIGHS WERE ADJUSTED DOWNWARD SEVERAL
DEGREES...MAINLY ACROSS THE INTERIOR. HIGHS MAY NOT GET OUT OF
THE UPPER 30S WELL INLAND. ELSEWHERE...TEMPS SHOULD HOLD STEADY
OR SLIGHTLY FALL FROM THEIR CURRENT READINGS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
NEXT UPPER TROUGH AND VORT SWINGS THROUGH THE AREA IN ASSOCIATION
WITH THE SURFACE LOW OVER THE OHIO VALLEY. PRECIPITATION WILL MOVE
BACK IN QUICKLY THIS EVENING IN THE WARM AIR AHEAD OF A STRONG
COLD FRONT. PRECIPITATION WILL BE MORE SHOWERY...AND ALL RAIN AS
COLD AIR LAGS UNTIL AFTER THE PRECIPITATION ENDS.
STRONG FRONT SWEEPS THROUGH LATE TONIGHT INTO EARLY FRIDAY
MORNING. WITH STRONG COLD ADVECTION AND MIXING OF 40 TO 50 KT LOW
LEVEL WINDS ADVISORY LEVEL GUSTS WILL BE LIKELY DURING FRIDAY.
WITH A STRONG PRESSURE GRADIENT EVEN SOME OF THE SUSTAINED WINDS
WILL BE NEAR ADVISORY LEVELS. COLD ADVECTION SUBSIDES IN THE
AFTERNOON WITH SUBSIDING WINDS. HIGHS WILL LIKELY OCCUR EARLY IN
THE MORNING WITH TEMPERATURES FALLING THROUGH THE DAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
WINDS WILL SLOWLY DIMINISH LATE FRI NIGHT...BUT SHOULD PICK UP
AGAIN SAT MORNING THOUGH NOT REACHING SPEEDS QUITE AS HIGH AS
THOSE OF FRI. SLOW MOVING SFC COLD FRONT DROPPING DOWN FROM THE N
WILL MAINTAIN CLOUDS ESPECIALLY ACROSS INTERIOR SECTIONS. THIS
FRONT SHOULD MOVE THROUGH SAT NIGHT...FINALLY USHERING IN SOME
VERY COLD AIR FOR SAT NIGHT THROUGH MON AS STRONG CANADIAN HIGH
PRES BUILDS ACROSS.
AS THE HIGH MOVES TO THE EAST MON NIGHT INTO TUE...RETURN FLOW
BETWEEN THE HIGH AND AN APPROACHING COLD FRONT WILL BRING QUICK
MODERATION TO SEVERAL DEG ABOVE NORMAL TUE INTO TUE EVENING.
DEEP LAYER WAA AHEAD OF THE FRONT WILL SUPPORT A LARGE SWATH OF
PRE-FRONTAL CLOUDS TUE INTO TUE NIGHT...ALSO A FEW RAIN/SNOW SHOWERS
MAINLY TUE NIGHT. FAIR WX WITH NEAR AVG TEMPERATURES WILL RETURN FOR
WED.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
LOW PRESSURE PASSES JUST SOUTH OF LONG ISLAND THIS AFTERNOON. A
POWERFUL COLD FRONT PASSES FRI MRNG.
SCATTERED AREAS OF LIGHT RAIN IN THE AREA THIS AFTERNOON. TEMPO
MVFR VSBYS PSBL WITH -RA AND BR. MODERATE CONFIDENCE REGARDING
CEILING FORECAST. CIGS MAY DROP TO IFR AT SOME TERMINALS. WIND
FORECAST ALSO MODERATE CONFIDENCE. TREND WILL BE WINDS SHIFTING TO
THE N-NW THEN EVENTUALLY W-SW...BUT TIMING MAY NEED TO BE AMENDED.
SUSTAINED WIND SPEEDS AND GUSTS DIMINISH...BUT AMENDMENTS ALSO
POSSIBLE FOR TIMING.
LOW CIGS EXPECTED TO CONTINUE TONIGHT...WITH A SMALL CHANCE THAT
SOME TERMINALS MAY LIFT TO VFR THIS EVENING.
COLD FRONT APPROACHES TOWARDS MORNING. MODERATE CONFIDENCE OF
RAINFALL...WITH POSSIBILITY THAT SOME TERMINALS SEE EITHER BRIEF
OR NO RAIN. CIGS COULD ALTERNATE BETWEEN MVFR AND IFR. ALSO CHANCE
OF SNOW MIXED WITH RAIN AT KSWF.
HIGH CONFIDENCE OF GUSTY WINDS FRIDAY...BEGINNING IN THE MORNING.
COULD SEE GUSTS AS HIGH AS 40KT AT TIMES. HIGH CONFIDENCE OF WIND
DIRECTION LEFT OF 310 AT NYC TERMINALS. VFR BY LATE MORNING.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS
THIS AFTERNOON...BUT SHOULD TREND TO NW AND THEN WSW. GUSTS MAY
DIMINISH EARLIER THAN FORECAST. PERIODIC MVFR VSBYS PSBL.
KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS
THIS AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN WSW. SW FLOW
MAY DEVELOP HERE EARLIER THAN AT KLGA/KEWR. GUSTS MAY DIMINISH
EARLIER THAN FORECAST. IFR CIGS AND MVFR VSBYS PSBL AT TIMES.
KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS
THIS AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN WSW. SW FLOW
MAY DEVELOP HERE EARLIER THAN AT KLGA/KEWR. GUSTS MAY DIMINISH
EARLIER THAN FORECAST. OCCASIONAL IFR CIGS/VSBYS POSSIBLE.
KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS
THIS AFTERNOON...BUT SHOULD TREND TO NW AND THEN WSW. SW FLOW MAY
DEVELOP HERE EARLIER THAN AT KLGA/KEWR. CIGS/VSBYS MAY FLUCTUATE
BETWEEN MVFR AND IFR AT TIMES.
KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE TO REFINE TIMING OF WIND SHIFTS
THIS AFTERNOON...BUT SHOULD TREND TO NW AND THEN WSW. CIGS MAY
FLUCTUATE BETWEEN MVFR AND IFR AT TIMES. CHANCE OF MVFR VSBYS.
KISP FCSTER COMMENTS: CIGS MAY VARY BETWEEN IFR AND MVFR. MVFR
VSBYS MAY LINGER LONGER THAN FORECAST. AMENDMENTS POSSIBLE TO REFINE
TIMING WIND SHIFTS THIS AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN
WSW. GUSTS MAY DIMINISH EARLIER THAN FORECAST.
OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
FRI AFTERNOON...VFR. WIND GUSTS AROUND 35KT...POSSIBLY EXCEEDING
40 KT AT TIMES.
SAT...VFR. FLURRIES POSSIBLE. GUSTY NW-W WINDS.
SUN-MON...VFR.
TUE...SUB-VFR PSBL.
&&
.MARINE...
GALES REMAIN UP ON ALL THE WATERS THIS MORNING. A STRONG LOW
LEVEL JET ASSOCIATED WITH AN AREA OF LOW PRESSURE PASSING OVER THE
AREA WATERS WILL MIX DOWN TO THE SURFACE BRINGING A PERIOD OF
STRONG GUSTY WINDS THIS MORNING. THE STRONGEST WINDS ARE EXPECTED
BETWEEN 5 AM AND 10 AM...WITH SOME LINGERING STRONGER GUSTS ACROSS
THE EASTERN WATERS. WINDS THEN RAPIDLY DIMINISH TO SMALL CRAFT
LEVELS THIS AFTERNOON. THERE MAY EVEN BE A PERIOD WHERE WINDS FALL
BELOW SMALL CRAFT LEVELS OVERNIGHT OUT AHEAD OF THE NEXT COLD
FRONT. SEAS HOWEVER WILL REMAIN AT SCA LEVELS.
SOUTHERLY WINDS RAPIDLY INCREASE ONCE AGAIN...THIS TIME OUT AHEAD
OF A COLD FRONT FRIDAY MORNING. HIGH CONFIDENCE EXISTS FOR STRONG
WESTERLY GALES DEVELOPING FRIDAY AND FRIDAY NIGHT BEHIND THE COLD
FRONT...WITH GUSTS UP TO 45 KT AND OCEAN SEAS BUILDING AS HIGH AS 16
FT OUT EAST FRI EVENING...AND UP TO 9 FT ON ERN LONG ISLAND SOUND.
THERE MAY EVEN BE A FEW GUSTS TO STORM FORCE. HAVE DECIDED NOT TO
ISSUE A NEW GALE WATCH OR WARNING FOR THIS EVENT TO AVOID CONFUSION
BETWEEN IT AND THE NEAR TERM FORECAST GALES...AS THERE SHOULD BE
ABOUT A 12-HR LULL BETWEEN THE TWO.
GALES SHOULD STILL BE ONGOING OVER THE OCEAN WATERS AND POSSIBLY THE
ERN SOUND/BAYS INTO SAT. GRADUAL IMPROVEMENT TO SUB-SCA EXPECTED SAT
NIGHT...WITH POSSIBLE OCEAN SCA CONDS RETURNING ON SUNDAY AS COLDER
AIR MOVES IN FROM THE NORTH.
&&
.HYDROLOGY...
RAINFALL AMOUNTS RANGED FROM 1 TO 1.5 INCHES FROM THIS EVENT. NO
FLOODING PROBLEMS ARE ANTICIPATED. AN ADDITIONAL TENTH TO TWO
TENTHS OF RAINFALL IS POSSIBLE LATE TONIGHT INTO FRIDAY MORNING.
DRY WEATHER RETURNS LATE FRIDAY THROUGH THE WEEKEND.
&&
.TIDES/COASTAL FLOODING...
THE COASTAL FLOOD ADVISORY HAS BEEN EXPANDED TO INCLUDE ALL ZONES
ADJACENT TO LI SOUND...AS WELL AS THE PECONIC AND GARDINERS BAYS.
THIS IS DUE TO A CHANGE IN LOW TRACK THAT HAS KEPT A STRONG...
PERSISTENT E/NE FLOW ACROSS LI SOUND. THIS HAS RESULTED IN
SIGNIFICANT TIDAL PILING WITH TIDAL DEPARTURES RUNNING AROUND 3
FT ABOVE NORMAL. THESE WATER LEVELS WILL BE SLOW TO RECEDE. IN FACT...
A COASTAL FLOOD WARNING MAY BE REQUIRED ACROSS WESTERN LI SOUND
SHOULD THESE LEVELS SHOW NO SIGH OF COMING DOWN IN THE NEXT HOUR.
THE COASTAL FLOOD ADVISORY ACROSS NY HARBOR AND THE SOUTH SHORE OF
WESTERN LI SOUND WILL EXPIRE AT NOON. THERE WAS WIDESPREAD MINOR
FLOODING ACROSS THESE AREAS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
CTZ009>012.
NY...COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ078-079-081.
COASTAL FLOOD WARNING UNTIL 3 PM EST THIS AFTERNOON FOR NYZ071-
073-176-177.
NJ...NONE.
MARINE...GALE WARNING FROM 6 AM FRIDAY TO MIDNIGHT EST FRIDAY NIGHT FOR
ANZ330-335-338-340-345-350-353-355.
SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ330-
335-340.
SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...KCS
MARINE...
HYDROLOGY...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1241 PM EST THU JAN 12 2012
.SYNOPSIS...
LOW PRESSURE SOUTH OF LONG ISLAND WILL DRIFT TO OUR EAST THIS
AFTERNOON. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE
OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS
SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL
AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1100 AM...DROPPED WEATHER ADVISORIES FOR OUR HUDSON VALLEY
FROM THE CAPITAL DISTRICT SOUTHWARD....AS WELL AS WESTERN ULSTER
COUNTY AND NORTHERN LITCHFIELD COUNTY. SOME OF THESE AREAS HAVE BEEN
REPORTING A MIX...BUT WITH TEMPERATURES ABOVE FREEZING...NO MORE
ACCUMULATIONS ARE EXPECTED.
WE KEPT THE WINTER WEATHER ADVISORY UP FOR MOST OF THE THE HIGHER
TERRAIN SURROUNDING THE CAPITAL DISTRICT AS TEMPERATURES WERE STILL
IN SOME CASES...BELOW FREEZING. THE ADVISORY IS MAINLY FOR POCKETS
OF FREEZING. WITH THE EXCEPTION OF THE ADIRONDACKS...ANY ADDITIONAL
ACCUMULATIONS IN THESE AREA OF SNOW WOULD ONLY 1-2 INCHES. THE
ADIRONDACKS COULD SEE UP TO 3 INCHES ADDITIONAL SNOWFALL...BUT MOST
AREAS EVEN THERE WILL CLOSE TO AN INCH.
TEMPERATURES WILL SLOWLY RISE TO AT OR ABOVE FREEZING HIGHER TERRAIN
AND AREA NORTH OF ALBANY...WITH VALLEY AREAS 35 TO 40. SOME AREAS
PRIMED TO DOWNSLOPING WINDS OFF THE HIGHER TERRAIN COULD REACH INTO
THE LOWER 40S.
**********PREVIOUS NEAR TERM DISCUSSION****************
AS OF 830 AM...THE FIRST BIG BATCH OF PRECIPITATION...MAINLY AS SNOW
FROM ALBANY NORTH...MIX FURTHER SOUTH...HAS LIFTED NORTHWARD. THIS
WAS ASSOCIATED WITH THE FRONTOGENETIC FORCING.
ANOTHER BATCH OF PRECIPITATION WAS WORKING UP THE HUDSON
VALLEY...ASSOCIATED WITH THE ACTUAL UPPER LEVEL LOW. WE HONESTLY ARE
NOT SURE WHAT EXACT FORM THIS PRECIPITATION WAS FALLING. SUSPECT
MAINLY RAIN...MIXED WITH POCKETS OF FREEZING RAIN AND SLEET. HOWEVER
IT MOVES NORTHWARD...IT COULD TRANSLATE BACK TO SNOW FROM ALBANY
NORTH BASED ON OUR SOUNDING. WHILE TEMPERATURES AT ALBANY HAVE
SLIPPED ABOVE FREEZING...THE FREEZING LEVEL IS QUITE...ONLY A 1000
FEET OR SO OFF THE GROUND...SO IT WOULDN`T TAKE MUCH MELTING
SNOWFLAKES TO COOL THE COLUMN.
UPDATED FORECAST TO REFLECT CURRENT TRENDS BUT DECIDED TO LEAVE ALL
FLAGS UP FOR NOW. THUS FAR...FREEZING RAIN HAS NOT BE
PREVALENT...BUT MORE OF RAIN/SNOW SITUATION (WITH A LITTLE SLEET AS
WELL).
********PREVIOUS NEAR TERM FORECAST********
AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH
THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE
MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH
TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN
ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS
NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING
ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION
FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING
HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN
ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE
WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT
CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND
ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED
ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER
BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS
AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR
THE SOUTHERN ADIRONDACKS.
AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA
PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO
THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED
ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW
HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA
HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF
FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF
MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS
VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL
TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE
SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE
AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE
NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA
BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS
FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN
TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL
HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS
EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS
MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE
ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH
FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM
YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO
LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE
MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS
OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE
VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP
TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE
SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS.
EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO
UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S
NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY
SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST
AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR
ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION
OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH
OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS.
THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS
OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE
EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES
A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE
AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI.
POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL
MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC
FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES
OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE
SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT
THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED
IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN
FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW
FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES
ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION
DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL
WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S.
SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS
OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES
THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF
THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY
HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE
TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN
RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY
COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS
GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW
NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA
TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES
ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON
SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN
TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE
DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE
THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE
SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR
EXPECTED FOR THIS TIME OF THE YEAR.
IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY
ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO.
HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND
INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW
SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL
ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK
VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO
SLIGHT CHC FOR THE REMAINDER OF SATURDAY.
HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL
CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE
COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR
MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT
AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND
UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT
WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE
GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS.
A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT
LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED
WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS
WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON
ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM
UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING
THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL
NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY
AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH
TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER
LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS.
IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE
REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD
AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR
WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
LOW CONFIDENCE FORECAST FOR MAINLY THE TONIGHT PERIOD.
THE STORM THAT IMPACTED THE TAFS EARLIER...WAS PULLING AWAY TO THE
EAST OF LONG ISLAND. IN ITS WAKE...LOTS OF MVFR CLOUDS WILL PERSIST.
THEN...ANOTHER DISTURBANCE AND COLD FRONT WILL APPROACH THE TAF
SITES ON FRIDAY...BRINGING MUCH COLDER AIR BEHIND IT.
THE BULK OF THE PRECIPITATION ASSOCIATED WITH THE STORM...IS
FINISHED. THERE MIGHT BE SOME OCCASIONAL DRIZZLE BUT THAT SHOULD BE
MAINLY IT THROUGH THIS EVENING. WILL CONTINUE WITH THE VCSH TO
REFLECT THE POSSIBILITY OF SHOWERS THROUGH THE EVENING.
SHOWERS WILL BREAK OUT LATER OVERNIGHT INTO FRIDAY...MIXING WITH
SNOW BY MIDDAY AT ALL TAF SITES.
THE PROBLEM TONIGHT IS RIGHT NOW WE ARE ASSUMING THE CLOUDS WILL
HOLD. IF THEY DO...ALL THE TAFS WILL LIKELY HAVE MVFR CONDITIONS
(MAINLY CIG...AOB 2000 FEET). HOWEVER...IF THE CLOUDS WERE TO THIN
OR EVEN CLEAR OUT (WHICH WE LEAN AGAINST BUT CERTAINLY
POSSIBLE)...SOME IFR FOG IS POSSIBLE...ESPECIALLY AT KGFL. THE WIND
ALOFT LOOKS REMAIN 30KTS OR HIGHER (WELL OFF THE DECK) WHICH SHOULD
HELP MITIGATE THE FORMATION OF IFR FOG. FOR NOW...NO MENTION OF IFR
UNTIL THE SHOWERS BEGIN TURNING TO SNOW...WHICH LOOKS TO BE AROUND
15Z FRIDAY. HOWEVER...IF THE FRONT MOVES IN FASTER...THE CHANGEOVER
COULD EVEN BE A LITTLE QUICKER.
THE NORTHERLY WIND 5-10 KTS WILL TURN SOUTHERLY LATER TOWARD
EVENING. THEY WILL TEND TO INCREASE A LITTLE OVERNIGHT...ESPECIALLY
AT KALB. THEN...THEY WILL SHIFT INTO THE WEST OR SOUTHWEST...AND
BECOME GUSTY AT KALB.
NOT SHOWN IN THE TAFS IS THAT THE WIND LOOKS TO BECOME STRONG AT ALL
THE TAF SITES BY LATER FRIDAY AFTERNOON...POSSIBLY GUSTING TO OVER
30KTS...ESPECIALLY AT KALB. THERE MIGHT ALSO BE INTENSE SNOW SQUALLS
BRIEFLY REDUCING VISIBILITY TO WELL UNDER A MILE.
BEST TO CHECK IN WITH THE FORECAST/DISCUSSION FOR LATER UPDATES.
OUTLOOK...
FRI NT...MAINLY VFR...WINDY. CHC MVFR -SHSN.
SUN-MON...VFR...NO SIG WX.
TUE...VFR...CHC MVFR -RASN.
&&
.HYDROLOGY...
A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO
BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING
TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN
ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED
WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG
ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST
OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID
EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH
BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE
TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH
IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION.
THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL
REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH
SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS
SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS.
TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A
DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE
NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH
AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN
AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE
COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS
SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF
AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL
BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND.
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...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-042-043-082.
MA...NONE.
VT...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
VTZ013>015.
&&
$$
SYNOPSIS...HWJIV/11/NAS
NEAR TERM...HWJIV/11
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...HWJIV
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
1105 AM EST THU JAN 12 2012
.SYNOPSIS...
LOW PRESSURE SOUTH OF LONG ISLAND WILL DRIFT TO OUR EAST THIS
AFTERNOON. ANOTHER LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE
OHIO VALLEY TONIGHT INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS
SOUTH AND MIXED PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL
AS BLUSTERY AND COLD CONDITIONS TO CLOSE THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1100 AM...DROPPED WEATHER ADVISORIES FOR OUR HUDSON VALLEY
FROM THE CAPITAL DISTRICT SOUTHWARD....AS WELL AS WESTERN ULSTER
COUNTY AND NORTHERN LITCHFIELD COUNTY. SOME OF THESE AREAS HAVE BEEN
REPORTING A MIX...BUT WITH TEMPERATURES ABOVE FREEZING...NO MORE
ACCUMULATIONS ARE EXPECTED.
WE KEPT THE WINTER WEATHER ADVISORY UP FOR MOST OF THE THE HIGHER
TERRAIN SURROUNDING THE CAPITAL DISTRICT AS TEMPERATURES WERE STILL
IN SOME CASES...BELOW FREEZING. THE ADVISORY IS MAINLY FOR POCKETS
OF FREEZING. WITH THE EXCEPTION OF THE ADIRONDACKS...ANY ADDITIONAL
ACCUMULATIONS IN THESE AREA OF SNOW WOULD ONLY 1-2 INCHES. THE
ADIRONDACKS COULD SEE UP TO 3 INCHES ADDITIONAL SNOWFALL...BUT MOST
AREAS EVEN THERE WILL CLOSE TO AN INCH.
TEMPERATURES WILL SLOWLY RISE TO AT OR ABOVE FREEZING HIGHER TERRAIN
AND AREA NORTH OF ALBANY...WITH VALLEY AREAS 35 TO 40. SOME AREAS
PRIMED TO DOWNSLOPING WINDS OFF THE HIGHER TERRAIN COULD REACH INTO
THE LOWER 40S.
**********PREVIOUS NEAR TERM DISCUSSION****************
AS OF 830 AM...THE FIRST BIG BATCH OF PRECIPITATION...MAINLY AS SNOW
FROM ALBANY NORTH...MIX FURTHER SOUTH...HAS LIFTED NORTHWARD. THIS
WAS ASSOCIATED WITH THE FRONTOGENETIC FORCING.
ANOTHER BATCH OF PRECIPITATION WAS WORKING UP THE HUDSON
VALLEY...ASSOCIATED WITH THE ACTUAL UPPER LEVEL LOW. WE HONESTLY ARE
NOT SURE WHAT EXACT FORM THIS PRECIPITATION WAS FALLING. SUSPECT
MAINLY RAIN...MIXED WITH POCKETS OF FREEZING RAIN AND SLEET. HOWEVER
IT MOVES NORTHWARD...IT COULD TRANSLATE BACK TO SNOW FROM ALBANY
NORTH BASED ON OUR SOUNDING. WHILE TEMPERATURES AT ALBANY HAVE
SLIPPED ABOVE FREEZING...THE FREEZING LEVEL IS QUITE...ONLY A 1000
FEET OR SO OFF THE GROUND...SO IT WOULDN`T TAKE MUCH MELTING
SNOWFLAKES TO COOL THE COLUMN.
UPDATED FORECAST TO REFLECT CURRENT TRENDS BUT DECIDED TO LEAVE ALL
FLAGS UP FOR NOW. THUS FAR...FREEZING RAIN HAS NOT BE
PREVALENT...BUT MORE OF RAIN/SNOW SITUATION (WITH A LITTLE SLEET AS
WELL).
********PREVIOUS NEAR TERM FORECAST********
AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH
THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE
MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH
TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN
ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS
NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING
ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION
FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING
HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN
ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE
WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT
CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND
ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED
ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER
BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS
AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR
THE SOUTHERN ADIRONDACKS.
AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA
PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO
THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED
ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW
HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA
HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF
FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF
MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS
VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL
TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE
SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE
AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE
NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA
BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS
FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN
TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL
HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS
EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS
MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE
ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH
FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM
YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO
LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE
MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS
OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE
VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP
TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE
SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS.
EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO
UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S
NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY
SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST
AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR
ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION
OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH
OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS.
THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS
OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE
EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES
A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE
AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI.
POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL
MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC
FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES
OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE
SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT
THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED
IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN
FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW
FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES
ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION
DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL
WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S.
SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS
OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES
THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF
THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY
HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE
TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN
RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY
COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS
GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW
NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA
TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES
ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON
SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN
TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE
DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE
THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE
SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR
EXPECTED FOR THIS TIME OF THE YEAR.
IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY
ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO.
HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND
INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW
SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL
ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK
VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO
SLIGHT CHC FOR THE REMAINDER OF SATURDAY.
HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL
CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE
COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR
MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT
AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND
UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT
WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE
GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS.
A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT
LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED
WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS
WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON
ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM
UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING
THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL
NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY
AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH
TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER
LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS.
IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE
REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD
AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR
WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
AS OF 800 AM...THE HEAVIEST PRECIPITATION HAS MOVED NORTH OF THE
TERMINALS. HOWEVER...THERE ARE MORE SHOWERS OF MAINLY RAIN WORKING
TOWARD KPOU.
REMOVED LLWS FROM KPOU SINCE THEY ARE REPORTING WIND GUSTS TO NEAR
20KTS AND THE ALY RAOB INDICATED THE WIND AT 2000 FEET AROUND 35KT
(NOT 45KTS). NARROWED THE TIME OF LLWS FROM MID TO LATER MORNING AT
KALB AND KGFL AS THAT IS WHEN THE STRONGEST WIND ALOFT MOVE THROUGH.
ALSO REMOVED ANY MENTION OF FREEZING RAIN FROM KGFL.
IFR/MVFR STRADDLE AT BOTH KALB AND KGFL BUT AS PCPN CHANGES TO RAIN
MVFR CONDITIONS WILL PREVAIL. WILL KEEP CIGS PREVAILING AT 2000 FEET
OR LESS ALTHOUGH WITH A DOWNSLOPING WIND...EVEN THESE MIGHT
OCCASIONALLY RISE UP TO VFR AS THEY DID AT KALB JUST BEFORE 800 AM.
OUR INCOMING 12Z RAOB STILL INDICATED A PRETTY STRONG ESE WIND OFF
THE DECK AT AROUND 1500 FEET. HOWEVER...IT MIGHT BE QUITE A STRONG
AS FORECASTED BY THE MODELS. WE WILL REVIEW THE LOW LEVEL WIND SHEAR
ASPECT WHEN THE ENTIRE RAOB COMES THROUGH. FOR NOW...CONTINUE WITH
LOW LEVEL WIND SHEAR UP TO 2000 FEET WITH AN E OR ESE WIND AROUND
40/45KTS THROUGH MUCH OF THE MORNING.
EVEN AFTER THE SYSTEM PASSED BY LATER TODAY...WE SHOULD HOLD ONTO
MVFR CLOUDS THROUGH MUCH OF THE NIGHT. AS LONG THAT HAPPENS...ANY
IFR FOG SHOULD BE LIMITED. HOWEVER...CONFIDENCE IN THIS THINKING IS
ONLY MODERATE...SO THIS PORTION OF THE TAF COULD CHANGE WITH
TIME.
ANOTHER UPPER LEVEL DISTURBANCE AND COLD FRONT WILL LIKELY BRING
ANOTHER ROUND OF RAIN SHOWERS ON FRIDAY...SWITCHING TO SNOW SHOWERS
AS THE DAY WEARS ON. THE WIND WILL PICK UP FROM THE WEST AND THERE
COULD EVEN BE SOME MORE INTENSE SNOW SQUALLS.
OUTLOOK...
FRI-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS
SNOW. BECOMING WINDY.
SAT-MON...VFR...NO SIG WX.
&&
.HYDROLOGY...
A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO
BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING
TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN
ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED
WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG
ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST
OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID
EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH
BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE
TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH
IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION.
THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL
REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH
SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS
SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS.
TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A
DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE
NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH
AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN
AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE
COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS
SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF
AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL
BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND.
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...NONE.
NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041-
043-047-048-051-082>084.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-042.
MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001.
VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014.
&&
$$
SYNOPSIS...HWJIV/11/NAS
NEAR TERM...HWJIV/11
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...HWJIV
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1107 AM EST THU JAN 12 2012
.SYNOPSIS...
A STORM SYSTEM FROM THE OHIO VALLEY TO THE SOUTHERN NEW ENGLAND
COAST WILL MOVE SLOWLY TO THE NORTH AND EAST THROUGH FRIDAY. A
STRONG COLD FRONT WILL MOVE ACROSS THE REGION EARLY FRIDAY
MORNING. HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING LOW THROUGH
THE WEEKEND. HIGH PRESSURE REMAINS INTO THE BEGINNING OF THE WEEK.
ANOTHER COLD FRONT MOVES THROUGH THE AREA TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
GREATEST PRESSURE FALLS WERE JUST OFF THE SE NEW ENGLAND COAST
LATE THIS MORNING. THIS WOULD SUPPORT THE COASTAL LOW TO THE
SOUTH OF LI TAKING A TRACK TO THE E/SE OF THE TRI-STATE AREA.
12Z NAM AND RUC SUPPORT SUCH A TRACK. THIS WILL IN PART PRODUCE
SOMEWHAT COOLER HIGHS TODAY...ESPECIALLY ACROSS THE INTERIOR...BUT
ALSO KEEP THE WINDS IN A MORE NORTHERLY DIRECTION. IN ADDITION...A
STRONG NE FLOW CONTINUES ACROSS COASTAL LOCATIONS THIS MORNING WITH
GUSTS UP TO 30 MPH. THE GRADIENT WILL SLACKEN BY THIS AFTERNOON AS
THE LOW TRACKS TO THE NE OF THE AREA. MORE IMPORTANTLY...THIS MAY
EXACERBATE COASTAL FLOODING ACROSS LI SOUND THIS AFTERNOON. REFER
TO THE COASTAL FLOOD SECTION BELOW.
AS FOR THE RAIN AND EMBEDDED THUNDERSTORMS...THE MAIN AREA ACROSS
EASTERN CT AND EASTERN LI WILL LIFT TO THE NE AND CLEAR THE AREA
BY NOONTIME. THERE MAY BE PATCHES OF LIGHT RAIN THROUGH THE
AFTERNOON WITH WEAK LIFT AND MOISTURE IN PLACE.
DUE TO THE LOW TRACK...HIGHS WERE ADJUSTED DOWNWARD SEVERAL
DEGREES...MAINLY ACROSS THE INTERIOR. HIGHS MAY NOT GET OUT OF
THE UPPER 30S WELL INLAND. ELSEWHERE...TEMPS SHOULD HOLD STEADY
OR SLIGHTLY FALL FROM THEIR CURRENT READINGS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
NEXT UPPER TROUGH AND VORT SWINGS THROUGH THE AREA IN ASSOCIATION
WITH THE SURFACE LOW OVER THE OHIO VALLEY. PRECIPITATION WILL MOVE
BACK IN QUICKLY THIS EVENING IN THE WARM AIR AHEAD OF A STRONG
COLD FRONT. PRECIPITATION WILL BE MORE SHOWERY...AND ALL RAIN AS
COLD AIR LAGS UNTIL AFTER THE PRECIPITATION ENDS.
STRONG FRONT SWEEPS THROUGH LATE TONIGHT INTO EARLY FRIDAY
MORNING. WITH STRONG COLD ADVECTION AND MIXING OF 40 TO 50 KT LOW
LEVEL WINDS ADVISORY LEVEL GUSTS WILL BE LIKELY DURING FRIDAY.
WITH A STRONG PRESSURE GRADIENT EVEN SOME OF THE SUSTAINED WINDS
WILL BE NEAR ADVISORY LEVELS. COLD ADVECTION SUBSIDES IN THE
AFTERNOON WITH SUBSIDING WINDS. HIGHS WILL LIKELY OCCUR EARLY IN
THE MORNING WITH TEMPERATURES FALLING THROUGH THE DAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
WINDS WILL SLOWLY DIMINISH LATE FRI NIGHT...BUT SHOULD PICK UP
AGAIN SAT MORNING THOUGH NOT REACHING SPEEDS QUITE AS HIGH AS
THOSE OF FRI. SLOW MOVING SFC COLD FRONT DROPPING DOWN FROM THE N
WILL MAINTAIN CLOUDS ESPECIALLY ACROSS INTERIOR SECTIONS. THIS
FRONT SHOULD MOVE THROUGH SAT NIGHT...FINALLY USHERING IN SOME
VERY COLD AIR FOR SAT NIGHT THROUGH MON AS STRONG CANADIAN HIGH
PRES BUILDS ACROSS.
AS THE HIGH MOVES TO THE EAST MON NIGHT INTO TUE...RETURN FLOW
BETWEEN THE HIGH AND AN APPROACHING COLD FRONT WILL BRING QUICK
MODERATION TO SEVERAL DEG ABOVE NORMAL TUE INTO TUE EVENING.
DEEP LAYER WAA AHEAD OF THE FRONT WILL SUPPORT A LARGE SWATH OF
PRE-FRONTAL CLOUDS TUE INTO TUE NIGHT...ALSO A FEW RAIN/SNOW SHOWERS
MAINLY TUE NIGHT. FAIR WX WITH NEAR AVG TEMPERATURES WILL RETURN FOR
WED.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE PASSES OVER THE METRO LATE THIS MORNING AND EARLY
AFTERNOON...THEN NE OF THE REGION THIS AFTERNOON. A POWERFUL COLD
FRONT PASSES FRI MRNG.
AS OF 1450Z...RAIN HAS MOVED NORTH AND EAST OF THE NYC TERMINALS
AND WILL CONTINUE MOVING TO THE NORTHEAST. MODERATE CONFIDENCE ON
CIGS/VSBYS WITH LOW STRATUS AND FOG CONTINUING OVER THE REGION.
MOST SIGNIFICANT CHANGE TO 15Z TAF UPDATE RELATES TO NYC TERMINAL
WINDS. LOOKS LIKE LOW PRESSURE WILL TRACK JUST EAST OF
NYC...CAUSING WINDS TO SHIFT N-NW LATE MORNING THROUGH EARLY
AFTERNOON BEFORE SETTLING TO THE SW. MODERATE CONFIDENCE REGARDING
GUSTS. GUSTS MAY DIMINISH EARLIER THAN FORECAST OVER THE NYC METROS.
LATEST DATA SUGGESTS MVFR CIGS LAST THRU THE DAY AND OVERNIGHT. BAND
OF RAIN LATE TONIGHT AHEAD OF THE COLD FRONT. THIS COULD MIX WITH
AND CHANGE TO SNOW...ESPECIALLY KSWF.
STRONG WINDS DEVELOP BEHIND THE COLD FRONT FRI MRNG.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE
MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN
W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. PERIODIC MVFR VSBYS
PSBL.
KJFK FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE
MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN
W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. IFR CIGS PSBL AT TIMES.
KLGA FCSTER COMMENTS: CIGS/VSBYS MAY IMPROVE TO MVFR EARLIER THAN
FORECAST. AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING
INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS
MAY DIMINISH EARLIER THAN FORECAST.
KTEB FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE
MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN
W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. OCCASIONAL IFR CIGS PSBL.
KHPN FCSTER COMMENTS: CIGS/VSBYS MAY VARY BETWEEN IFR AND MVFR.
AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY
AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY
DIMINISH EARLIER THAN FORECAST.
KISP FCSTER COMMENTS: CIGS/VSBYS MAY VARY BETWEEN IFR AND MVFR.
AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY
AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY
DIMINISH EARLIER THAN FORECAST.
OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
FRI...CHANCE FOR IFR OR MVFR IN SNOW/RAIN SHOWERS. W-NW WINDS WITH
GUSTS ABOVE 40 KT.
SAT...VFR. FLURRIES POSSIBLE. GUSTY NW-W WINDS.
SUN...VFR. GUSTY N WINDS LATE.
MON...VFR.
&&
.MARINE...
GALES REMAIN UP ON ALL THE WATERS THIS MORNING. A STRONG LOW
LEVEL JET ASSOCIATED WITH AN AREA OF LOW PRESSURE PASSING OVER THE
AREA WATERS WILL MIX DOWN TO THE SURFACE BRINGING A PERIOD OF
STRONG GUSTY WINDS THIS MORNING. THE STRONGEST WINDS ARE EXPECTED
BETWEEN 5 AM AND 10 AM...WITH SOME LINGERING STRONGER GUSTS ACROSS
THE EASTERN WATERS. WINDS THEN RAPIDLY DIMINISH TO SMALL CRAFT
LEVELS THIS AFTERNOON. THERE MAY EVEN BE A PERIOD WHERE WINDS FALL
BELOW SMALL CRAFT LEVELS OVERNIGHT OUT AHEAD OF THE NEXT COLD
FRONT. SEAS HOWEVER WILL REMAIN AT SCA LEVELS.
SOUTHERLY WINDS RAPIDLY INCREASE ONCE AGAIN...THIS TIME OUT AHEAD
OF A COLD FRONT FRIDAY MORNING. HIGH CONFIDENCE EXISTS FOR STRONG
WESTERLY GALES DEVELOPING FRIDAY AND FRIDAY NIGHT BEHIND THE COLD
FRONT...WITH GUSTS UP TO 45 KT AND OCEAN SEAS BUILDING AS HIGH AS 16
FT OUT EAST FRI EVENING...AND UP TO 9 FT ON ERN LONG ISLAND SOUND.
THERE MAY EVEN BE A FEW GUSTS TO STORM FORCE. HAVE DECIDED NOT TO
ISSUE A NEW GALE WATCH OR WARNING FOR THIS EVENT TO AVOID CONFUSION
BETWEEN IT AND THE NEAR TERM FORECAST GALES...AS THERE SHOULD BE
ABOUT A 12-HR LULL BETWEEN THE TWO.
GALES SHOULD STILL BE ONGOING OVER THE OCEAN WATERS AND POSSIBLY THE
ERN SOUND/BAYS INTO SAT. GRADUAL IMPROVEMENT TO SUB-SCA EXPECTED SAT
NIGHT...WITH POSSIBLE OCEAN SCA CONDS RETURNING ON SUNDAY AS COLDER
AIR MOVES IN FROM THE NORTH.
&&
.HYDROLOGY...
RAINFALL AMOUNTS RANGED FROM 1 TO 1.5 INCHES FROM THIS EVENT. NO
FLOODING PROBLEMS ARE ANTICIPATED. AN ADDITIONAL TENTH TO TWO
TENTHS OF RAINFALL IS POSSIBLE LATE TONIGHT INTO FRIDAY MORNING.
DRY WEATHER RETURNS LATE FRIDAY THROUGH THE WEEKEND.
&&
.TIDES/COASTAL FLOODING...
THE COASTAL FLOOD ADVISORY HAS BEEN EXPANDED TO INCLUDE ALL ZONES
ADJACENT TO LI SOUND...AS WELL AS THE PECONIC AND GARDINERS BAYS.
THIS IS DUE TO A CHANGE IN LOW TRACK THAT HAS KEPT A STRONG...
PERSISTENT E/NE FLOW ACROSS LI SOUND. THIS HAS RESULTED IN
SIGNIFICANT TIDAL PILING WITH TIDAL DEPARTURES RUNNING AROUND 3
FT ABOVE NORMAL. THESE WATER LEVELS WILL BE SLOW TO RECEDE. IN FACT...
A COASTAL FLOOD WARNING MAY BE REQUIRED ACROSS WESTERN LI SOUND
SHOULD THESE LEVELS SHOW NO SIGH OF COMING DOWN IN THE NEXT HOUR.
THE COASTAL FLOOD ADVISORY ACROSS NY HARBOR AND THE SOUTH SHORE OF
WESTERN LI SOUND WILL EXPIRE AT NOON. THERE WAS WIDESPREAD MINOR
FLOODING ACROSS THESE AREAS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
CTZ009>012.
NY...COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ071-073-078-079-081-176-177.
COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR NYZ072-074-075-
178-179.
NJ...COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR NJZ006-106-108.
MARINE...GALE WARNING UNTIL NOON EST TODAY FOR ANZ330-335-338-340-345-
350-353-355.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...KCS
MARINE...
HYDROLOGY...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1104 AM EST THU JAN 12 2012
.SYNOPSIS...
A STORM SYSTEM FROM THE OHIO VALLEY TO THE SOUTHERN NEW ENGLAND
COAST WILL MOVE SLOWLY TO THE NORTH AND EAST THROUGH FRIDAY. A
STRONG COLD FRONT WILL MOVE ACROSS THE REGION EARLY FRIDAY
MORNING. HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING LOW THROUGH
THE WEEKEND. HIGH PRESSURE REMAINS INTO THE BEGINNING OF THE WEEK.
ANOTHER COLD FRONT MOVES THROUGH THE AREA TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
GREATEST PRESSURE FALLS WERE JUST OFF THE SE NEW ENGLAND COAST
LATE THIS MORNING. THIS WOULD SUPPORT THE COASTAL LOW TO THE
SOUTH OF LI TAKING A TRACK TO THE E/SE OF THE TRI-STATE AREA.
12Z NAM AND RUC SUPPORT SUCH A TRACK. THIS WILL IN PART PRODUCE
SOMEWHAT COOLER HIGHS TODAY...ESPECIALLY ACROSS THE INTERIOR...BUT
ALSO KEEP THE WINDS IN A MORE NORTHERLY DIRECTION. IN ADDITION...A
STRONG NE FLOW CONTINUES ACROSS COASTAL LOCATIONS THIS MORNING WITH
GUSTS UP TO 30 MPH. THE GRADIENT WILL SLACKEN BY THIS AFTERNOON AS
THE LOW TRACKS TO THE NE OF THE AREA. MORE IMPORTANTLY...THIS MAY
EXACERBATE COASTAL FLOODING ACROSS LI SOUND THIS AFTERNOON. REFER
TO COASTAL FLOOD SECTION BELOW.
AS FOR THE RAIN AND EMBEDDED THUNDERSTORMS...THE MAIN AREA ACROSS
EASTERN CT AND EASTERN LI WILL LIFT TO THE NE AND CLEAR THE AREA
BY NOONTIME. THERE MAY BE PATCHES OF LIGHT RAIN THROUGH THE
AFTERNOON WITH WEAK LIFT AND MOISTURE IN PLACE.
DUE TO THE LOW TRACK...HIGHS WERE ADJUSTED DOWNWARD SEVERAL
DEGREES...MAINLY ACROSS THE INTERIOR. HIGHS MAY NOT GET OUT OF
THE UPPER 30S WELL INLAND. ELSEWHERE...TEMPS SHOULD HOLD STEADY
OR SLIGHTLY FALL FROM THEIR CURRENT READINGS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
NEXT UPPER TROUGH AND VORT SWINGS THROUGH THE AREA IN ASSOCIATION
WITH THE SURFACE LOW OVER THE OHIO VALLEY. PRECIPITATION WILL MOVE
BACK IN QUICKLY THIS EVENING IN THE WARM AIR AHEAD OF A STRONG
COLD FRONT. PRECIPITATION WILL BE MORE SHOWERY...AND ALL RAIN AS
COLD AIR LAGS UNTIL AFTER THE PRECIPITATION ENDS.
STRONG FRONT SWEEPS THROUGH LATE TONIGHT INTO EARLY FRIDAY
MORNING. WITH STRONG COLD ADVECTION AND MIXING OF 40 TO 50 KT LOW
LEVEL WINDS ADVISORY LEVEL GUSTS WILL BE LIKELY DURING FRIDAY.
WITH A STRONG PRESSURE GRADIENT EVEN SOME OF THE SUSTAINED WINDS
WILL BE NEAR ADVISORY LEVELS. COLD ADVECTION SUBSIDES IN THE
AFTERNOON WITH SUBSIDING WINDS. HIGHS WILL LIKELY OCCUR EARLY IN
THE MORNING WITH TEMPERATURES FALLING THROUGH THE DAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
WINDS WILL SLOWLY DIMINISH LATE FRI NIGHT...BUT SHOULD PICK UP
AGAIN SAT MORNING THOUGH NOT REACHING SPEEDS QUITE AS HIGH AS
THOSE OF FRI. SLOW MOVING SFC COLD FRONT DROPPING DOWN FROM THE N
WILL MAINTAIN CLOUDS ESPECIALLY ACROSS INTERIOR SECTIONS. THIS
FRONT SHOULD MOVE THROUGH SAT NIGHT...FINALLY USHERING IN SOME
VERY COLD AIR FOR SAT NIGHT THROUGH MON AS STRONG CANADIAN HIGH
PRES BUILDS ACROSS.
AS THE HIGH MOVES TO THE EAST MON NIGHT INTO TUE...RETURN FLOW
BETWEEN THE HIGH AND AN APPROACHING COLD FRONT WILL BRING QUICK
MODERATION TO SEVERAL DEG ABOVE NORMAL TUE INTO TUE EVENING.
DEEP LAYER WAA AHEAD OF THE FRONT WILL SUPPORT A LARGE SWATH OF
PRE-FRONTAL CLOUDS TUE INTO TUE NIGHT...ALSO A FEW RAIN/SNOW SHOWERS
MAINLY TUE NIGHT. FAIR WX WITH NEAR AVG TEMPERATURES WILL RETURN FOR
WED.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE PASSES OVER THE METRO LATE THIS MORNING AND EARLY
AFTERNOON...THEN NE OF THE REGION THIS AFTERNOON. A POWERFUL COLD
FRONT PASSES FRI MRNG.
AS OF 1450Z...RAIN HAS MOVED NORTH AND EAST OF THE NYC TERMINALS
AND WILL CONTINUE MOVING TO THE NORTHEAST. MODERATE CONFIDENCE ON
CIGS/VSBYS WITH LOW STRATUS AND FOG CONTINUING OVER THE REGION.
MOST SIGNIFICANT CHANGE TO 15Z TAF UPDATE RELATES TO NYC TERMINAL
WINDS. LOOKS LIKE LOW PRESSURE WILL TRACK JUST EAST OF
NYC...CAUSING WINDS TO SHIFT N-NW LATE MORNING THROUGH EARLY
AFTERNOON BEFORE SETTLING TO THE SW. MODERATE CONFIDENCE REGARDING
GUSTS. GUSTS MAY DIMINISH EARLIER THAN FORECAST OVER THE NYC METROS.
LATEST DATA SUGGESTS MVFR CIGS LAST THRU THE DAY AND OVERNIGHT. BAND
OF RAIN LATE TONIGHT AHEAD OF THE COLD FRONT. THIS COULD MIX WITH
AND CHANGE TO SNOW...ESPECIALLY KSWF.
STRONG WINDS DEVELOP BEHIND THE COLD FRONT FRI MRNG.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE
MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN
W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. PERIODIC MVFR VSBYS
PSBL.
KJFK FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE
MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN
W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. IFR CIGS PSBL AT TIMES.
KLGA FCSTER COMMENTS: CIGS/VSBYS MAY IMPROVE TO MVFR EARLIER THAN
FORECAST. AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING
INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS
MAY DIMINISH EARLIER THAN FORECAST.
KTEB FCSTER COMMENTS: AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE
MORNING INTO EARLY AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN
W. GUSTS MAY DIMINISH EARLIER THAN FORECAST. OCCASIONAL IFR CIGS PSBL.
KHPN FCSTER COMMENTS: CIGS/VSBYS MAY VARY BETWEEN IFR AND MVFR.
AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY
AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY
DIMINISH EARLIER THAN FORECAST.
KISP FCSTER COMMENTS: CIGS/VSBYS MAY VARY BETWEEN IFR AND MVFR.
AMENDMENTS LIKELY TO REFINE WIND SHIFTS LATE MORNING INTO EARLY
AFTERNOON...BUT SHOULD TREND TO N-NW AND THEN W. GUSTS MAY
DIMINISH EARLIER THAN FORECAST.
OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
FRI...CHANCE FOR IFR OR MVFR IN SNOW/RAIN SHOWERS. W-NW WINDS WITH
GUSTS ABOVE 40 KT.
SAT...VFR. FLURRIES POSSIBLE. GUSTY NW-W WINDS.
SUN...VFR. GUSTY N WINDS LATE.
MON...VFR.
&&
.MARINE...
GUSTS UP TO 45 KT POSSIBLE ACROSS EASTERN LI SOUND THROUGH MID
MORNING AS THE LOW-LEVEL JET PIVOTS ACROSS THE WATERS.
GALES REMAIN UP ON ALL THE WATERS THIS MORNING. A STRONG LOW LEVEL
JET ASSOCIATED WITH AN AREA OF LOW PRESSURE PASSING OVER THE AREA
WATERS WILL MIX DOWN TO THE SURFACE BRINGING A PERIOD OF STRONG
GUSTY WINDS THIS MORNING. THE STRONGEST WINDS ARE EXPECTED BETWEEN 5
AM AND 10 AM...WITH SOME LINGERING STRONGER GUSTS ACROSS THE EASTERN
WATERS. WINDS THEN RAPIDLY DIMINISH TO SMALL CRAFT LEVELS THIS
AFTERNOON. THERE MAY EVEN BE A PERIOD WHERE WINDS FALL BELOW SMALL
CRAFT LEVELS OVERNIGHT OUT AHEAD OF THE NEXT COLD FRONT. SEAS
HOWEVER WILL REMAIN AT SCA LEVELS.
SOUTHERLY WINDS RAPIDLY INCREASE ONCE AGAIN...THIS TIME OUT AHEAD
OF A COLD FRONT FRIDAY MORNING. HIGH CONFIDENCE EXISTS FOR STRONG
WESTERLY GALES DEVELOPING FRIDAY AND FRIDAY NIGHT BEHIND THE COLD
FRONT...WITH GUSTS UP TO 45 KT AND OCEAN SEAS BUILDING AS HIGH AS 16
FT OUT EAST FRI EVENING...AND UP TO 9 FT ON ERN LONG ISLAND SOUND.
THERE MAY EVEN BE A FEW GUSTS TO STORM FORCE. HAVE DECIDED NOT TO
ISSUE A NEW GALE WATCH OR WARNING FOR THIS EVENT TO AVOID CONFUSION
BETWEEN IT AND THE NEAR TERM FORECAST GALES...AS THERE SHOULD BE
ABOUT A 12-HR LULL BETWEEN THE TWO.
GALES SHOULD STILL BE ONGOING OVER THE OCEAN WATERS AND POSSIBLY THE
ERN SOUND/BAYS INTO SAT. GRADUAL IMPROVEMENT TO SUB-SCA EXPECTED SAT
NIGHT...WITH POSSIBLE OCEAN SCA CONDS RETURNING ON SUNDAY AS COLDER
AIR MOVES IN FROM THE NORTH.
&&
.HYDROLOGY...
THREE QUARTERS TO AROUND 1 INCH OF RAINFALL IS EXPECTED THROUGH
MIDDAY TODAY. MINOR URBAN AND POOR DRAINAGE FLOODING IS POSSIBLE
THIS MORNING.
AN ADDITIONAL TENTH TO TWO TENTHS OF RAINFALL IS POSSIBLE LATE
TONIGHT INTO FRIDAY MORNING. DRY WEATHER RETURNS LATE FRIDAY
THROUGH THE WEEKEND.
&&
.TIDES/COASTAL FLOODING...
THE COASTAL FLOOD ADVISORY HAS BEEN EXPANDED TO INCLUDE ALL ZONES
ADJACENT TO LI SOUND...AS WELL AS THE PECONIC AND GARDINERS BAYS.
THIS IS DUE TO A CHANGE IN LOW TRACK THAT HAS KEPT A STRONG...
PERSISTENT E/NE FLOW ACROSS LI SOUND. THIS HAS RESULTED IN
SIGNIFICANT TIDAL PILING WITH TIDAL DEPARTURES RUNNING AROUND 3
FT ABOVE NORMAL. THESE WATER LEVELS WILL BE SLOW TO RECEDE. IN FACT...
A COASTAL FLOOD WARNING MAY BE REQUIRED ACROSS WESTERN LI SOUND
SHOULD THESE LEVELS SHOW NO SIGH OF COMING DOWN IN THE NEXT HOUR.
THE COASTAL FLOOD ADVISORY ACROSS NY HARBOR AND THE SOUTH SHORE OF
WESTERN LI SOUND WILL EXPIRE AT NOON. THERE WAS WIDESPREAD MINOR
FLOODING ACROSS THESE AREAS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...COASTAL FLOOD ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
CTZ009.
NY...COASTAL FLOOD ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ072-
074-075-178-179.
COASTAL FLOOD ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NYZ071-073-176-177.
NJ...COASTAL FLOOD ADVISORY UNTIL 11 AM EST THIS MORNING FOR NJZ006-
106-108.
MARINE...GALE WARNING UNTIL NOON EST TODAY FOR ANZ330-335-338-340-345-
350-353-355.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
832 AM EST THU JAN 12 2012
.SYNOPSIS...
A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION
TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE
PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM
THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A
COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW
PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT
INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED
PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY
AND COLD CONDITIONS TO CLOSE THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 830 AM...THE FIRST BIG BATCH OF PRECIPITATION...MAINLY AS SNOW
FROM ALBANY NORTH...MIX FURTHER SOUTH...HAS LIFTED NORTHWARD. THIS
WAS ASSOCIATED WITH THE FRONTOGENETIC FORCING.
ANOTHER BATCH OF PRECIPITATION WAS WORKING UP THE HUDSON
VALLEY...ASSOCIATED WITH THE ACTUAL UPPER LEVEL LOW. WE HONESTLY ARE
NOT SURE WHAT EXACT FORM THIS PRECIPITATION WAS FALLING. SUSPECT
MAINLY RAIN...MIXED WITH POCKETS OF FREEZING RAIN AND SLEET. HOWEVER
IT MOVES NORTHWARD...IT COULD TRANSLATE BACK TO SNOW FROM ALBANY
NORTH BASED ON OUR SOUNDING. WHILE TEMPERATURES AT ALBANY HAVE
SLIPPED ABOVE FREEZING...THE FREEZING LEVEL IS QUITE...ONLY A 1000
FEET OR SO OFF THE GROUND...SO IT WOULDN`T TAKE MUCH MELTING
SNOWFLAKES TO COOL THE COLUMN.
UPDATED FORECAST TO REFLECT CURRENT TRENDS BUT DECIDED TO LEAVE ALL
FLAGS UP FOR NOW. THUS FAR...FREEZING RAIN HAS NOT BE
PREVALENT...BUT MORE OF RAIN/SNOW SITUATION (WITH A LITTLE SLEET AS
WELL).
********PREVIOUS NEAR TERM FORECAST********
AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH
THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE
MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH
TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN
ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS
NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING
ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION
FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING
HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN
ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE
WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT
CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND
ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED
ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER
BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS
AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR
THE SOUTHERN ADIRONDACKS.
AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA
PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO
THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED
ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW
HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA
HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF
FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF
MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS
VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL
TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE
SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE
AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE
NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA
BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS
FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN
TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL
HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS
EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS
MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE
ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH
FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM
YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO
LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE
MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS
OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE
VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP
TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE
SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS.
EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO
UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S
NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY
SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST
AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR
ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION
OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH
OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS.
THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS
OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE
EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES
A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE
AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI.
POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL
MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC
FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES
OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE
SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT
THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED
IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN
FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW
FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES
ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION
DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL
WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S.
SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS
OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES
THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF
THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY
HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE
TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN
RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY
COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS
GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW
NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA
TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES
ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON
SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN
TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE
DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE
THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE
SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR
EXPECTED FOR THIS TIME OF THE YEAR.
IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY
ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO.
HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND
INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW
SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL
ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK
VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO
SLIGHT CHC FOR THE REMAINDER OF SATURDAY.
HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL
CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE
COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR
MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT
AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND
UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT
WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE
GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS.
A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT
LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED
WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS
WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON
ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM
UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING
THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL
NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY
AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH
TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER
LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS.
IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE
REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD
AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR
WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 800 AM...THE HEAVIEST PRECIPITATION HAS MOVED NORTH OF THE
TERMINALS. HOWEVER...THERE ARE MORE SHOWERS OF MAINLY RAIN WORKING
TOWARD KPOU.
REMOVED LLWS FROM KPOU SINCE THEY ARE REPORTING WIND GUSTS TO NEAR
20KTS AND THE ALY RAOB INDICATED THE WIND AT 2000 FEET AROUND 35KT
(NOT 45KTS). NARROWED THE TIME OF LLWS FROM MID TO LATER MORNING AT
KALB AND KGFL AS THAT IS WHEN THE STRONGEST WIND ALOFT MOVE THROUGH.
ALSO REMOVED ANY MENTION OF FREEZING RAIN FROM KGFL.
IFR/MVFR STRADDLE AT BOTH KALB AND KGFL BUT AS PCPN CHANGES TO RAIN
MVFR CONDITIONS WILL PREVAIL. WILL KEEP CIGS PREVAILING AT 2000 FEET
OR LESS ALTHOUGH WITH A DOWNSLOPING WIND...EVEN THESE MIGHT
OCCASIONALLY RISE UP TO VFR AS THEY DID AT KALB JUST BEFORE 800 AM.
OUR INCOMING 12Z RAOB STILL INDICATED A PRETTY STRONG ESE WIND OFF
THE DECK AT AROUND 1500 FEET. HOWEVER...IT MIGHT BE QUITE A STRONG
AS FORECASTED BY THE MODELS. WE WILL REVIEW THE LOW LEVEL WIND SHEAR
ASPECT WHEN THE ENTIRE RAOB COMES THROUGH. FOR NOW...CONTINUE WITH
LOW LEVEL WIND SHEAR UP TO 2000 FEET WITH AN E OR ESE WIND AROUND
40/45KTS THROUGH MUCH OF THE MORNING.
EVEN AFTER THE SYSTEM PASSED BY LATER TODAY...WE SHOULD HOLD ONTO
MVFR CLOUDS THROUGH MUCH OF THE NIGHT. AS LONG THAT HAPPENS...ANY
IFR FOG SHOULD BE LIMITED. HOWEVER...CONFIDENCE IN THIS THINKING IS
ONLY MODERATE...SO THIS PORTION OF THE TAF COULD CHANGE WITH
TIME.
ANOTHER UPPER LEVEL DISTURBANCE AND COLD FRONT WILL LIKELY BRING
ANOTHER ROUND OF RAIN SHOWERS ON FRIDAY...SWITCHING TO SNOW SHOWERS
AS THE DAY WEARS ON. THE WIND WILL PICK UP FROM THE WEST AND THERE
COULD EVEN BE SOME MORE INTENSE SNOW SQUALLS.
OUTLOOK...
FRI-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS
SNOW. BECOMING WINDY.
SAT-MON...VFR...NO SIG WX.
&&
.HYDROLOGY...
A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO
BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING
TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN
ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED
WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG
ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST
OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID
EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH
BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE
TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH
IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION.
THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL
REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH
SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS
SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS.
TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A
DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE
NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH
AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN
AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE
COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS
SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF
AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL
BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND.
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 NOON EST TODAY FOR CTZ001.
NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041-
043-047>054-058-061-063-082>084.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-042.
MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001.
VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014.
&&
$$
SYNOPSIS...11/NAS
NEAR TERM...HWJIV/11
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...HWJIV
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
800 AM EST THU JAN 12 2012
.SYNOPSIS...
A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION
TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE
PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM
THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A
COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW
PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT
INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED
PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY
AND COLD CONDITIONS TO CLOSE THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH
THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE
MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH
TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN
ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS
NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING
ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION
FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING
HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN
ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE
WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT
CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND
ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED
ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER
BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS
AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR
THE SOUTHERN ADIRONDACKS.
AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA
PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO
THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED
ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW
HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA
HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF
FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF
MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS
VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL
TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE
SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE
AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE
NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA
BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS
FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN
TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL
HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS
EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS
MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE
ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH
FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM
YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO
LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE
MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS
OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE
VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP
TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE
SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS.
EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO
UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S
NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY
SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST
AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR
ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION
OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH
OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS.
THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS
OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE
EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES
A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE
AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI.
POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL
MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC
FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES
OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE
SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT
THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED
IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN
FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW
FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES
ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION
DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL
WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S.
SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS
OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES
THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF
THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY
HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE
TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN
RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY
COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS
GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW
NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA
TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES
ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON
SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN
TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE
DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE
THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE
SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR
EXPECTED FOR THIS TIME OF THE YEAR.
IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY
ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO.
HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND
INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW
SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL
ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK
VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO
SLIGHT CHC FOR THE REMAINDER OF SATURDAY.
HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL
CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE
COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR
MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT
AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND
UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT
WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE
GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS.
A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT
LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED
WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS
WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON
ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM
UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING
THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL
NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY
AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH
TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER
LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS.
IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE
REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD
AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR
WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
AS OF 800 AM...THE HEAVIEST PRECIPITATION HAS MOVED NORTH OF THE
TERMINALS. HOWEVER...THERE ARE MORE SHOWERS OF MAINLY RAIN WORKING
TOWARD KPOU.
REMOVED LLWS FROM KPOU SINCE THEY ARE REPORTING WIND GUSTS TO NEAR
20KTS AND THE ALY RAOB INDICATED THE WIND AT 2000 FEET AROUND 35KT
(NOT 45KTS). NARROWED THE TIME OF LLWS FROM MID TO LATER MORNING AT
KALB AND KGFL AS THAT IS WHEN THE STRONGEST WIND ALOFT MOVE THROUGH.
ALSO REMOVED ANY MENTION OF FREEZING RAIN FROM KGFL.
IFR/MVFR STRADDLE AT BOTH KALB AND KGFL BUT AS PCPN CHANGES TO RAIN
MVFR CONDITIONS WILL PREVAIL. WILL KEEP CIGS PREVAILING AT 2000 FEET
OR LESS ALTHOUGH WITH A DOWNSLOPING WIND...EVEN THESE MIGHT
OCCASIONALLY RISE UP TO VFR AS THEY DID AT KALB JUST BEFORE 800 AM.
OUR INCOMING 12Z RAOB STILL INDICATED A PRETTY STRONG ESE WIND OFF
THE DECK AT AROUND 1500 FEET. HOWEVER...IT MIGHT BE QUITE A STRONG
AS FORECASTED BY THE MODELS. WE WILL REVIEW THE LOW LEVEL WIND SHEAR
ASPECT WHEN THE ENTIRE RAOB COMES THROUGH. FOR NOW...CONTINUE WITH
LOW LEVEL WIND SHEAR UP TO 2000 FEET WITH AN E OR ESE WIND AROUND
40/45KTS THROUGH MUCH OF THE MORNING.
EVEN AFTER THE SYSTEM PASSED BY LATER TODAY...WE SHOULD HOLD ONTO
MVFR CLOUDS THROUGH MUCH OF THE NIGHT. AS LONG THAT HAPPENS...ANY
IFR FOG SHOULD BE LIMITED. HOWEVER...CONFIDENCE IN THIS THINKING IS
ONLY MODERATE...SO THIS PORTION OF THE TAF COULD CHANGE WITH
TIME.
ANOTHER UPPER LEVEL DISTURBANCE AND COLD FRONT WILL LIKELY BRING
ANOTHER ROUND OF RAIN SHOWERS ON FRIDAY...SWITCHING TO SNOW SHOWERS
AS THE DAY WEARS ON. THE WIND WILL PICK UP FROM THE WEST AND THERE
COULD EVEN BE SOME MORE INTENSE SNOW SQUALLS.
OUTLOOK...
FRI-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS
SNOW. BECOMING WINDY.
SAT-MON...VFR...NO SIG WX.
&&
.HYDROLOGY...
A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO
BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING
TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN
ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED
WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG
ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST
OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID
EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH
BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE
TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH
IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION.
THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL
REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH
SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS
SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS.
TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A
DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE
NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH
AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN
AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE
COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS
SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF
AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL
BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND.
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 NOON EST TODAY FOR CTZ001.
NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041-
043-047>054-058-061-063-082>084.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-042.
MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001.
VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014.
&&
$$
SYNOPSIS...11/NAS
NEAR TERM...11
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...HWJIV
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
657 AM EST THU JAN 12 2012
.SYNOPSIS...
A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION
TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE
PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM
THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A
COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW
PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT
INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED
PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY
AND COLD CONDITIONS TO CLOSE THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 7 AM EST...995 MB COASTAL LOW WAS LOCATED NEAR CAPE MAY WITH
THE PRIMARY LOW BACK ACROSS NORTHERN OHIO. BULK OF PCPN WITH THE
MAIN SURGE OF PCPN HAS TAPERED OFF FROM THE CAPITAL DISTRICT SOUTH
TEMPORARILY ALTHOUGH NEXT SURGE OF PCPN MAINLY IN THE FORM OF RAIN
ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS MOVING ACROSS
NORTHERN NEW JERSEY AND NORTHEAST PA. WILL LEAVE REMAINING
ADVISORIES IN PLACE FOR NOW AS STILL SOME MIXED PRECIPITATION
FALLING. AREAS TO THE NORTHWEST WHICH ARE STILL BELOW FREEZING
HAVE REPORTED A PROLONGED PERIOD OF SLEET AND FREEZING RAIN
ESPECIALLY ACROSS THE WESTERN MOHAWK VALLEY AND PORTIONS OF THE
WESTERN ADIRONDACKS. HAVE ADJUSTED HOURLY GRIDS TO BETTER FIT
CURRENT OBS AND RADAR TRENDS. ALSO HAVE ADJUSTED QPF...SNOW AND
ICE AMOUNTS SLIGHTLY TO REFLECT LATEST REPORTS AS WELL AS EXPECTED
ADDITIONAL AMOUNTS. BULK OF THE MIXED PCPN IS EXPECTED TO BE OVER
BY THE END OF THE MORNING COMMUTE EXCEPT ACROSS FAR NORTHERN AREAS
AND WILL KEEP ADVISORY UP THROUGH THE AFTERNOON AT THIS TIME FOR
THE SOUTHERN ADIRONDACKS.
AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA
PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO
THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED
ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW
HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA
HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF
FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF
MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS
VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL
TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE
SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE
AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE
NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA
BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS
FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN
TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL
HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS
EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS
MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE
ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH
FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM
YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO
LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE
MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS
OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE
VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP
TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE
SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS.
EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO
UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S
NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY
SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST
AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR
ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION
OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH
OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS.
THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS
OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE
EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES
A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE
AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI.
POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL
MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC
FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES
OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE
SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT
THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED
IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN
FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW
FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES
ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION
DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL
WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S.
SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS
OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES
THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF
THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY
HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE
TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN
RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY
COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS
GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW
NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA
TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES
ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON
SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN
TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE
DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE
THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE
SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR
EXPECTED FOR THIS TIME OF THE YEAR.
IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY
ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO.
HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND
INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW
SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL
ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK
VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO
SLIGHT CHC FOR THE REMAINDER OF SATURDAY.
HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL
CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE
COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR
MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT
AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND
UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT
WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE
GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS.
A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT
LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED
WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS
WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON
ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM
UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING
THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL
NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY
AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH
TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER
LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS.
IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE
REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD
AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR
WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
WINTRY PRECIPITATION IMPACTING KALB AND KGFL BUT WILL SOON
TRANSITION TO RAIN. MAINLY MVFR CONDITION WITH CIGS BELOW 2000 FEET
THROUGH MUCH OF THE DAY.
ONE BATCH OF HEAVIER SNOW WAS MOVING NORTH OF ALBANY. IN ITS
WAKE...MUCH LIGHTER PRECIPITATION WHICH SHOULD BECOME MAINLY
RAIN...EXCEPT STILL MIXED WITH SNOW AND SLEET AT KALB...AND EVEN A
LITTLE FREEZING RAIN AT KGFL...THROUGH MID MORNING.
OUR INCOMING 12Z RAOB STILL INDICATED A PRETTY STRONG ESE WIND OFF
THE DECK AT AROUND 1500 FEET. HOWEVER...IT MIGHT BE QUITE A STRONG
AS FORECASTED BY THE MODELS. WE WILL REVIEW THE LOW LEVEL WIND SHEAR
ASPECT WHEN THE ENTIRE RAOB COMES THROUGH. FOR NOW...CONTINUE WITH
LOW LEVEL WIND SHEAR UP TO 2000 FEET WITH AN E OR ESE WIND AROUND
40/45KTS THROUGH MUCH OF THE MORNING.
THESE ESE FLOW WILL RESULT IN DOWNSLOPE OFF THE HIGHER TERRAIN TO
THE EAST AND AS RESULT WILL LIKELY KEEP CIGS AND VSBY (ONCE THE PCPN
TURNS TO RAIN)...ABOVE IFR...IN THE LOW MVFR RANGE. HOWEVER...CIGS
LOOK TO REMAIN AT OR BELOW 2000 FEET MUCH OF THE DAY.
EVEN AFTER THE SYSTEM PASSED BY LATER TODAY...WE SHOULD HOLD ONTO
MVFR CLOUDS THROUGH MUCH OF THE NIGHT. AS LONG THAT HAPPENS...ANY
IFR FOG SHOULD BE LIMITED. HOWEVER...CONFIDENCE IN THIS THINKING IS
ONLY MODERATE...SO THIS PORTION OF THE TAF COULD CHANGE WITH
TIME.
ANOTHER UPPER LEVEL DISTURBANCE AND COLD FRONT WILL LIKELY BRING
ANOTHER ROUND OF RAIN SHOWERS ON FRIDAY...SWITCHING TO SNOW SHOWERS
AS THE DAY WEARS ON. THE WIND WILL PICK UP FROM THE WEST AND THERE
COULD EVEN BE SOME MORE INTENSE SNOW SQUALLS.
OUTLOOK...
FRI-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS
SNOW. BECOMING WINDY.
SAT-MON...VFR...NO SIG WX.
HWJIV
OUTLOOK...
THU NT-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS
SNOW. BCMG WINDY FRI.
SAT-MON...VFR...NO SIG WX.
&&
.HYDROLOGY...
A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO
BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING
TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN
ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED
WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG
ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST
OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID
EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH
BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE
TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH
IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION.
THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL
REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH
SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS
SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS.
TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A
DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE
NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH
AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN
AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE
COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS
SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF
AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL
BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND.
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 NOON EST TODAY FOR CTZ001.
NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041-
043-047>054-058-061-063-082>084.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-042.
MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001.
VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014.
&&
$$
SYNOPSIS...11/NAS
NEAR TERM...11
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...HWJIV
HYDROLOGY...11
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ALBANY NY
512 AM EST THU JAN 12 2012
.SYNOPSIS...
A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION
TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE
PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM
THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A
COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW
PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT
INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED
PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY
AND COLD CONDITIONS TO CLOSE THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA
PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO
THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED
ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW
HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA
HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF
FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF
MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS
VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL
TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE
SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE
AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE
NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA
BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS
FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN
TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL
HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS
EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS
MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE
ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH
FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM
YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO
LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE
MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS
OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE
VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP
TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE
SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS.
EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO
UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S
NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY
SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST
AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR
ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION
OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH
OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS.
THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS
OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE
EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES
A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE
AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI.
POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL
MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC
FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES
OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE
SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT
THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED
IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN
FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW
FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES
ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION
DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL
WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S.
SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS
OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES
THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF
THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY
HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE
TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN
RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY
COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS
GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW
NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA
TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES
ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON
SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN
TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE
DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE
THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE
SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR
EXPECTED FOR THIS TIME OF THE YEAR.
IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY
ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO.
HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND
INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW
SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL
ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK
VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO
SLIGHT CHC FOR THE REMAINDER OF SATURDAY.
HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL
CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE
COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR
MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT
AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND
UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT
WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE
GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS.
A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT
LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED
WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS
WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON
ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM
UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING
THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL
NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY
AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH
TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER
LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS.
IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE
REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD
AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR
WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
AS OF 515 AM...SNOW HAS REACHED KGFL AND CONTINUED AT KALB. RAIN
FALLING AT KPOU.
WARMER AIR ALOFT....AND LIGHTER PCPN AMOUNTS WILL ALLOW THE PCPN TO
MIX WITH SLEET AND RAIN AND EVENTUALLY CHANGE TO ALL RAIN LATER THIS
MORNING. IFR CONDITIONS WILL LIKELY TRANSITION TO MVFR LATER THIS
MORNING SINCE THE PCPN GOES TO RAIN AND WE ARE LOOKING AT AN
EASTERLY DOWNSLOPE COMPONENT AT ALL TAF SITES.
DUE TO THE STRENGTH OF THIS SYSTEM...LLWS DOES SEEM TO BE INCREASING
AND EVIDENCE IS SHOWING UP IN THE VWP. SO WE WILL INCLUDE LLWS FOR
ALL TAF SITES OVERNIGHT AND TOWARD SUNRISE THURSDAY.
PRECIP WILL BEGIN TO TAPER OFF AS WE DRY SLOT THROUGH THE DAY
THURSDAY.
OUTLOOK...
THU NT-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS
SNOW. BECMG WINDY FRI.
SAT-MON...VFR...NO SIG WX.
&&
.HYDROLOGY...
A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO
BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING
TRANSITIONING TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN
ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED
WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG
ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST
OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID
EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH
BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE
TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH
IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE GEORGE REGION.
THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL
REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH
SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS
SNOW...SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS.
TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A
DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE
NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH
AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN
AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE
COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS
SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF
AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL
BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND.
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 NOON EST TODAY FOR CTZ001.
NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041-
043-047>054-058-061-063-082>084.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-042.
MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001.
VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014.
&&
$$
SYNOPSIS...11/NAS
NEAR TERM...11
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...BGM
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
506 AM EST THU JAN 12 2012
.SYNOPSIS...
A COMPLEX STORM SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION
TO EASTERN NEW YORK AND WESTERN NEW ENGLAND TODAY. THE
PRECIPITATION WILL TRANSITION TO RAINFALL DURING THIS MORNING FROM
THE CAPITAL REGION AND THE MOHAWK VALLEY SOUTH AND EAST...AS A
COASTAL LOW QUICKLY MOVES NORTHEAST OF LONG ISLAND. ANOTHER LOW
PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT
INTO FRIDAY WITH MAINLY RAIN AND SNOW SHOWERS SOUTH AND MIXED
PRECIPITATION TRANSITIONING TO SNOW NORTH...AS WELL AS BLUSTERY
AND COLD CONDITIONS TO CLOSE THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 4 AM EST...995 MB COASTAL LOW HAS MOVED OVER THE DELMARVA
PENINSULA AND IS TRACKING TOWARD LONG ISLAND AS THE PRIMARY LOW TO
THE WEST REMAINS OVER NORTH CENTRAL OHIO. TEMPERATURES HAVE COOLED
ACROSS MOST OF THE CENTRAL PORTION OF THE FA DURING THE LAST FEW
HOURS AS DEWPOINTS HAVE RISEN. FAR NORTHERN PORTIONS OF THE FA
HAVE SEEN TEMPS AND DEWPOINTS RISE WITH FAR SOUTHEAST PORTION OF
FA NOT ABLE TO TAP ENOUGH COLD AIR TO SUPPORT MUCH IN THE WAY OF
MIXED PCPN WITH MOSTLY RAIN OCCURRING. PARTIAL THICKNESS
VALUES...MODEL SOUNDINGS AND HRRR TEMPS ALL SUPPORT A GRADUAL
TRANSITION DURING THE MORNING TO ALL RAIN EXCEPT ACROSS THE
SOUTHERN ADIRONDACKS WHERE A WINTRY MIX WILL CONTINUE INTO THE
AFTERNOON. BEST FRONTOGENESIS IS NOW OCCURRING ACROSS THE
NORTHERN HALF OF FA AND THIS WILL SLIDE NORTH AND EAST OF THE FA
BY 12Z. ALREADY SEEING SOME BREAKS IN THE PCPN OCCURRING ACROSS
FAR SOUTHEAST PORTION OF FA AND EXPECT THAT THIS WILL CAUSE PCPN
TO DIMINISH IN INTENSITY FROM SOUTH TO NORTH OVER THE NEXT SEVERAL
HOURS...ALTHOUGH ONE MORE ROUND OF FAIRLY INTENSE PCPN IS
EXPECTED ASSOCIATED WITH THE UPPER TROUGH AND VORT AXIS LATER THIS
MORNING. HAVE ADJUSTED POPS TO REFLECT RADAR TRENDS...PTYPE
ADJUSTED BY PARTIAL THICKNESS VALUES GOING CLOSER TO MAV WITH
FORECAST ESSENTIALLY BACK TO THAT WHICH WAS ISSUED AT 4 AM
YESTERDAY. SNOW AMOUNTS WERE GENERALLY CREATED USING A SNOW TO
LIQUID RATIO OF 6:1. HIGHEST SNOWFALL ACCUMULATIONS WILL BE IN THE
MOUNTAINS WHERE 2 TO 6 INCHES OF SNOW IS EXPECTED...HIGHEST TOTALS
OVER SOUTHERN GREEN MOUNTAINS WITH GENERALLY AN INCH OR TWO IN THE
VALLEYS. ICE ACCRETION WILL GENERALLY BE AN INCH OR LESS EXCEPT UP
TO A QUARTER OF AN INCH IS POSSIBLE ACROSS PORTIONS OF THE
SOUTHERN ADIRONDACKS AND THE SOUTHERN GREEN MOUNTAINS.
EXPECT TEMPS TO SLOWLY RISE FROM CURRENT VALUES IN THE MID TO
UPPER 20S NORTH AND LOW TO MID 30S SOUTH TO THE LOW TO MID 30S
NORTH AND UPPER 30S TO MID 40S SOUTH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY
SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST
AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR
ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION
OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH
OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS.
THERMAL PROFILES WILL REMAIN A CHALLENGE...ESPECIALLY FOR PORTIONS
OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE
EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES
A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE
AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI.
POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL
MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC
FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES
OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE
SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT
THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED
IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN
FACT...TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW
FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES
ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION
DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL
WHICH WILL BE MONITORED CLOSELY. FURTHERMORE...LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S.
SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS
OF THE MOHAWK VALLEY...SOUTHERN DACKS. DUE TO FORECAST CHALLENGES
THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF
THE INVERSION LEVELS DROPPING BELOW 5K FEET...WE WILL NOT HOIST ANY
HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
OVER THE WEEKEND...THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE
TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN
RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER...IT WON/T BE BRUTALLY
COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS
GENERALLY NEAR NORMAL...WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW
NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA
TEMPS OF AROUND -15 DEGREES C FOR SATURDAY...AND -16 TO -18 DEGREES
ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON
SATURDAY...AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN
TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE
DIGITS...WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE
THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE
SEASON SO FAR...IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR
EXPECTED FOR THIS TIME OF THE YEAR.
IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY
ALLOW FOR SOME CLOUDS...ESP IN AREAS DOWNWIND OF LAKE ONTARIO.
HOWEVER...THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT...AND
INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW
SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL
ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK
VALLEY/SCHOHARIE COUNTY FOR SAT MORNING...BEFORE LOWERING POPS TO
SLIGHT CHC FOR THE REMAINDER OF SATURDAY.
HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL
CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE
COOL SIDE...BUT NOTHING UNHEARD OF FOR MID JANUARY...WITH 20S FOR
MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT
AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND
UP BEING EARLIER IN THE NIGHT...AS TEMPS MAY SLOWLY RISE OVERNIGHT
WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW...HAVE
GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS.
A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT
LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED
WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS
WILL ALLOW FOR SOME RAIN/SNOW SHOWERS...WITH P-TYPE DEPENDENT ON
ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM
UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN...ESP CONSIDERING
THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL
NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY
AREAS...WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH
TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER
LIGHT...WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS.
IN THE WAKE OF THIS SYSTEM...COOLER AIR WILL AGAIN FILTER INTO THE
REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD
AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR
WEDNESDAY...WITH MAINLY TEENS AND 20S FOR MAX TEMPS.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
THE ONSET OF THE PRECIP WAS ADVANCING NORTHWARD COINCIDING WITH IFR
CONDITIONS AND INTERACTING WITH A VERY COMPLEX SURFACE
TEMPERATURES. FOR KPOU...A MAINLY RAIN EVENT EXPECTED. FURTHER
NORTH...A WINTRY MIXTURE FOR KALB THROUGH THIS EARLY THURSDAY
MORNING. KGFL...MAINLY SNOW THROUGH THIS EARLY THURSDAY MORNING
WITH A TRANSITION TOWARD SOME SLEET. AS WARMER AIR ADVANCES
NORTHWARD...A PERIOD OF SLEET AND FREEZING RAIN IS EXPECTED BEFORE
CHANGING OVER TO MAINLY RAIN TOWARD THE NOON HOUR. DUE TO THE
STRENGTH OF THIS SYSTEM...LLWS DOES SEEM TO BE INCREASING AND
EVIDENCE IS SHOWING UP IN THE VWP. SO WE WILL INCLUDE LLWS FOR ALL
TAF SITES OVERNIGHT AND TOWARD SUNRISE THURSDAY.
PRECIP WILL BEGIN TO TAPER OFF AS WE DRY SLOT THROUGH THE DAY
THURSDAY.
OUTLOOK...
THU NT-FRI NT...MVFR/IFR...RAIN OR MIXED PRECIPITATION ENDING AS
SNOW. BECMG WINDY FRI.
SAT-MON...VFR...NO SIG WX.
&&
.HYDROLOGY...
A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO BRING
MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING TRANSITIONING
TO ALL RAIN...ESPECIALLY SOUTH AND EAST OF THE SOUTHERN
ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED
WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG
ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST
OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID
EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN
INCH BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO
REDUCE TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF
AN INCH IN THE UPPER HUDSON VALLEY...AND PORTIONS OF THE LAKE
GEORGE REGION. THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF
THE CAPITAL REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN
STEM RIVERS WITH SOME MINOR RISES AT BEST. MOST OF THE
PRECIPITATION WILL FALL AS SNOW...SLEET AND FREEZING RAIN OVER THE
NORTHERN BASINS.
TONIGHT...A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS...WITH A
DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE
NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH
AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN
AND SNOW SHOWERS ON FRIDAY....AS IT MOVES OVER UPSTATE NY. THERE
COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS
SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF
AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL
BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND.
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 NOON EST TODAY FOR CTZ001.
NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ038>041-
043-047>054-058-061-063-082>084.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-042.
MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ001-025.
WIND ADVISORY UNTIL NOON EST TODAY FOR MAZ001.
VT...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VTZ013>015.
WIND ADVISORY UNTIL NOON EST TODAY FOR VTZ013-014.
&&
$$
SYNOPSIS...11/NAS
NEAR TERM...11
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...BGM
HYDROLOGY...11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1254 AM EST THU JAN 12 2012
.PREV DISCUSSION... /ISSUED 906 PM EST WED JAN 11 2012/
UPDATE...
FORECAST IS ON TRACK TONIGHT. WILL CONTINUE TO SEE EXTENSIVE CLOUD
COVERAGE OVERNIGHT BUT FOR THE MOST PART THE PRECIP HAS LIFTED OUT
OF THE AREA. RUC PROGS A WEAK VORT MAX QUICKLY MOVING ACROSS THE
STATE OVER THE NEXT FEW HOURS...BUT SEEING AS THIS ISNT PRODUCING
SHOWERS IN AL...DO NOT EXPECT TO SEE ANY SHOWERS ASSOCIATED WITH
IT HERE. CUT BACK ON POPS OVERNIGHT AND ONLY LEFT THEM IN ACROSS
NORTHEAST GEORGIA. DID ADD PATCHY DRIZZLE THOUGH TONIGHT FOR
EXTREME NORTH GEORGIA.
11
PREV DISCUSSION...
SHORT TERM /TONIGHT THROUGH FRIDAY/...
/ISSUED 254 PM EST WED JAN 11 2012/
SHOWERS AND ISOLATED THUNDERSTORMS REMAINED ACROSS NORTH GEORGIA
THIS AFTERNOON AS A RESULT OF LOW PRESSURE MOVING THROUGH THE
AREA. ASSOCIATED COLD FRONT EXPECTED TO MOVE INTO THE CAROLINAS
THIS EVENING WILL HAVE LITTLE IMPACT TO THE CWA...AHEAD OF A
SECOND COLD FRONT THAT WILL QUICKLY PUSH THROUGH ON THURSDAY.
INITIALLY...WRAP AROUND MOISTURE WILL KEEP NORTH GEORGIA IN A
FAVORABLE PRECIP AREA...BUT THIS MOISTURE...COMBINED WITH THE
SOUTHERLY FLOW AHEAD OF THE NEXT FRONT...WILL BE ENOUGH TO KEEP
SLIGHT CHANCE TO CHANCE POPS ACROSS MAINLY NORTH GEORGIA THROUGH
THURSDAY AFTERNOON. BEHIND THIS BOUNDARY...MUCH COOLER
TEMPERATURES MOVE INTO THE AREA...WHICH WITH SOME RESIDUAL
MOISTURE...WILL BE ENOUGH TO PRODUCE LIGHT SNOW ACROSS NORTH
GEORGIA. HAVE GONE WITH GENERALLY SLIGHT CHANCE TO CHANCE LIGHT
SNOW ACROSS THE NORTHERNMOST TIER OF COUNTIES. MODELS ARE IN
FAIRLY GOOD AGREEMENT WITH THIS SOLUTION...AND DUE TO
INCONVENIENCES THAT MAY RESULT FROM THIS PRECIP...CONFIDENCE IS
HIGH ENOUGH TO GO AHEAD AND ISSUE THE WINTER WEATHER ADVISORY FOR
00Z TO 12Z FRIDAY. HPC WWD HAS THE AREA OUTLOOKED FOR 1 INCH OF
ACCUMULATIONS...AND HAVE GENERALLY SIDED MORE TOWARDS THE 0.5 TO 1
INCH RANGE...WITH THE HIGHER AMOUNTS IN THE HIGHER ELEVATIONS.
WITH WARM SURFACE TEMPERATURES...MOST OF THE ACCUMULATIONS WILL BE
ON THE ELEVATED SURFACES.
ADDITIONALLY...THE TIGHT PRESSURE GRADIENT OVER THE AREA RESULTING
FROM THESE SERIES OF SYSTEMS WILL ALLOW FOR STRONG TO GUSTY WINDS TO
IMPACT THE AREA ON THURSDAY. EXPECTING WINDS TO BE IN THE 15 TO 20
MPH RANGE...WITH GUSTS AS HIGH AS 35 MPH. HAVE ISSUED A WIND
ADVISORY FOR ALL OF NORTH AND CENTRAL GEORGIA FOR 10 AM THURSDAY
THROUGH MIDNIGHT.
ONCE THE COLD FRONT PUSHES THROUGH THE STATE THURSDAY...ASSOCIATED
PARENT LOW SWEEPS OVER NEW ENGLAND...AND PULLS ANY REMAINING WRAP
AROUND MOISTURE UP THE APPALACHIANS DURING THE DAY FRIDAY. SURFACE
HIGH PRESSURE BUILDS BACK INTO THE STATE...WITH DRY AND CHILLY
CONDITIONS PREVAILING ACROSS THE STATE.
MET OUT PERFORMED THE MAV ON THE TEMPERATURES YESTERDAY...AND EACH
HAS ITS STRENGTHS WITH THE CURRENT FORECAST...ONE BETTER ON
TEMPS...THE OTHER SEEMINGLY BETTER ON DEW POINTS. HAVE GENERALLY
GONE WITH A BLEND OF THE TWO...AND HEAVILY WEIGHTING THE LOCAL BIAS
NUMBERS. AS A RESULT...EXPECTING ONE LAST DAY WITH HIGHS IN THE MID
50S TO MID 60S ON THURSDAY. INFLUENCE OF THE COLD FRONT REALLY
PROMINENT ON FRIDAY MORNING AS TEMPS DROP INTO THE 20S AND LOW
30S...AND WITH HIGHS ONLY IN THE 40S FRIDAY AFTERNOON.
31
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
/ISSUED 254 PM EST WED JAN 11 2012/
SURFACE HIGH PRESSURE CONTROLS THE ENVIRONMENT THROUGH EARLY
WEEK...WITH DRY CONDITIONS PREVAILING...AND CHILLY TEMPERATURES
GRADUALLY WARMING. NEXT FRONTAL SYSTEM LOOKS TO MOVE INTO
NORTHWEST GEORGIA THROUGH EARLY TUESDAY. HAVE MADE NO MAJOR
CHANGES TO THE CURRENT FORECAST...AND SLIGHT CHANCE TO CHANCE POPS
ARE STILL EXPECTED TUESDAY AS THIS NEXT SYSTEM ENTERS THE REGION.
31
&&
.AVIATION...
06Z UPDATE...
EXPECT MVFR CIGS TO DOMINATE THROUGH MUCH OF THE PERIOD...THOUGH
MAY SEE A BRIEF PERIOD OF CIGS IN THE IFR RANGE 10Z TO 14Z TIME
FRAME. VSBYS GENERALLY UNRESTRICTED EXCEPT POSSIBLY LOWERING INTO
THE MVFR RANGE THIS AFTERNOON/EARLY EVENING IN SCATTERED LIGHT
SHOWERS AS A SECONDARY COLD FRONT MOVES ACROSS THE AREA. SOUTHWEST
WINDS 8 TO 12 KTS REST OF THE NIGHT...BECOMING MORE WESTERLY AND
INCREASING INTO THE 12 TO 18 KT RANGE BY MID MORNING THURSDAY WITH
GUSTS UP TO 30 KTS POSSIBLE IN THE AFTERNOON WITH THE FRONT MOVING
THROUGH.
//ATL CONFIDENCE...06Z UPDATE...
HIGH MOST ELEMENTS...EXCEPT MEDIUM ON THE DEVELOPMENT OF IFR CIGS
THIS MORNING.
49
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 63 28 47 24 / 20 10 0 5
ATLANTA 58 28 45 26 / 30 10 0 5
BLAIRSVILLE 50 23 37 18 / 50 30 0 5
CARTERSVILLE 57 29 43 20 / 30 20 0 5
COLUMBUS 64 29 49 27 / 20 5 0 5
GAINESVILLE 53 30 42 25 / 30 20 0 5
MACON 65 30 50 24 / 20 10 0 5
ROME 56 28 42 20 / 50 20 0 10
PEACHTREE CITY 59 26 46 20 / 20 10 0 5
VIDALIA 68 31 51 31 / 5 10 0 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT EST TONIGHT
FOR THE FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BARTOW...
BIBB...BLECKLEY...BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...
CHATTOOGA...CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...
CRAWFORD...CRISP...DADE...DAWSON...DEKALB...DODGE...DOOLY...
DOUGLAS...EMANUEL...FANNIN...FAYETTE...FLOYD...FORSYTH...
GILMER...GLASCOCK...GORDON...GREENE...GWINNETT...HALL...
HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON...
JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...
LAURENS...LUMPKIN...MACON...MADISON...MARION...MERIWETHER...
MONROE...MONTGOMERY...MORGAN...MURRAY...MUSCOGEE...NEWTON...
NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH...
PICKENS...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...SCHLEY...
SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TOWNS...TREUTLEN...
TROUP...TWIGGS...UNION...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITE...WHITFIELD...WILCOX...
WILKES...WILKINSON.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
FRIDAY FOR THE FOLLOWING ZONES: CATOOSA...DADE...FANNIN...
GILMER...LUMPKIN...MURRAY...TOWNS...UNION...WALKER...WHITE...
WHITFIELD.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
335 PM CST THU JAN 12 2012
.DISCUSSION...
134 PM CST
LIGHT TO MODERATE SNOWFALL CONTINUES ACROSS THE AREA EARLY THIS
AFTERNOON. RADAR TRENDS AND SHORT TERM GUIDANCE SHOW TWO AREAS OF
BETTER FORCING WITHIN THE BROAD LIFT. THE FIRST IS ORIENTED FROM
BENTON HARBOR MICHIGAN NORTHWEST ACROSS MILWAUKEE WITH A SECOND
STARTING TO TAKE SHAPE FROM RENSSELAER TO PRINCETON TO SAVANNA. IN
BETWEEN...RADAR RETURNS HAVE EASED OFF SOMEWHAT BUT SNOWFALL
CONTINUES. OVERALL NEAR TERM TRENDS SUGGEST THAT
FORCING/FRONTOGENESIS WILL BECOME MORE FOCUSED OVER THE CWA INTO
LATE AFTERNOON...WITH PERHAPS THE MOST FOCUSED FORCING OVER NE
IL/NW IN EARLY THIS EVENING.
IN ADDITION...LOW LEVEL AREA OF CONVERGENCE OVER THE LAKE
CONTINUES TO COMPLICATE NEAR TERM DETAILS. LATEST RUC SHOWS AN
EAST-WEST BAND OF CONVERGENCE FROM THE LAKE/COOK IL BORDER
EASTWARD. THIS TROUGH IS NOT SO EVIDENT IN SHORE OBS BUT ORD TDWR
SHOWS A SOUTHWESTWARD MOVING AREA OF ENHANCED REFLECTIVITY MOVING
INLAND FROM EVANSTON SOUTHWARD INTO DOWNTOWN CHICAGO. LAKE
INFLUENCE WILL LIKELY BE RATHER TRANSIENT BUT IS SEEMINGLY ABLE TO
OCCUR...AND MAY BECOME MORE FAVORED AS LOW-LEVEL THERMAL PROFILES
COOL. THE EXTENT TO WHICH IT OCCURS IS STILL NOT CLEAR BUT AREAS
ALONG THE COOK COUNTY IL SHORE SEEM MOST FAVORED INTO MID
AFTERNOON BEFORE IT PIVOTS INTO NORTHWEST INDIANA LATE THIS
AFTERNOON/EARLY THIS EVENING.
MDB
//PREV DISCUSSION...
1110 AM CST
HAVE OPTED TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER
STORM WARNING FOR MUCH OF NORTHEAST IL AND NORTHWEST IN. RADAR
TRENDS SHOW THE MAIN BAND OF SNOW INTENSIFYING AND BECOMING MORE
WIDESPREAD ACROSS MUCH OF THE FORECAST AREA AS IT LIFT
NORTHEASTWARD AND BEGINS TO PIVOT COUNTER-CLOCKWISE.
FRONTOGENETICAL FORCING BECOME BETTER FOCUSED AS MID LEVEL TROUGH
SWINGS ACROSS THE AREA BRINGING IN WARM ADVECTION FROM THE EAST
AND COLD ADVECTION FROM THE WEST. IN ADDITION...FOCUSING MAY BE
FURTHER ENHANCED BY THE PRESENCE OF A MID LEVEL TROUGH OF WARM AIR
ALOFT. THIS SYNOPTIC FORCING BY ITSELF SUGGESTS THAT SNOWFALL
RATES WILL BE HIGHER FROM MID AFTERNOON THROUGH EARLY EVENING
RESULTING IN 4-8 INCH TOTALS IN A SHORTER AMOUNT OF TIME. IN
ADDITION LAKE ENHANCEMENT IN SOME FORM STILL LOOKS POSSIBLE LATE
THIS AFTERNOON...BUT WILL BE VERY CHALLENGING TO PIN DOWN. SURFACE
OBS AROUND THE SOUTHERN SHORE STILL SHOW SIGNS OF A CIRCULATION
WITH RADAR SHOWING A NORTHWEST-SOUTHEAST ORIENTED BAND OF PRECIP
WHICH MAY BE REFLECTIVE MORE OF A ELONGATED CONVERGENCE AREA.
SEVERAL RECENT RUNS OF THE RUC/HRRR SHOW A CLOSED CIRCULATION
SHIFTING WESTWARD TOWARD THE IL SHORE THIS AFTERNOON WITH OTHER
GUIDANCE SHOWING AT LEAST SOME SORT OF SHORELINE CONVERGENCE
DEVELOPING. THE CHALLENGE WILL BE FOR THIS TO CONTINUE IN THE
MIDST OF INCREASING NORTHWESTERLY LOW LEVEL FLOW...WHICH HAS BEEN
SLOWER TO ADVANCE EASTWARD. SHOULD THIS LAKE ENHANCEMENT/BANDING
OCCUR...AND THIS IS STILL UNCERTAIN...THEN SOME AREAS COULD EASILY
SEE 8-10 INCHES OR POSSIBLY MORE BUT THIS WOULD LIKELY BE VERY
LOCALIZED. EVEN WITHOUT LAKE ENHANCEMENT SNOWFALL RATES ARE
EXPECTED TO BE HEAVIEST DURING THE AFTERNOON/EVENING RUSH
HOUR...WITH IMPACTS MAGNIFIED UNDER ANY LAKE BANDS. GUSTY WINDS
WILL SPREAD IN FROM THE WEST THROUGH THE AFTERNOON ACROSS NORTH
CENTRAL ILLINOIS AND INTO THE CHICAGO METRO LATE THIS
AFTERNOON/EARLY THIS EVENING AND THEN INTO NW INDIANA.
MDB
//PREV DISCUSSION...
309 AM CST
NEAR TERM (NOW THROUGH FRIDAY)...
VERY LITTLE CHANGE FROM PREVIOUS FORECAST WITH ONLY REAL ADJUSTMENT
BEING UPGRADING TO A WARNING FOR PORTER COUNTY DUE TO SOME LAKE
ENHANCEMENT THIS AFTERNOON POSSIBLY INTO VERY EARLY THIS EVENING.
POTENT VORT MAX EVIDENT ON WATER VAPOR IMAGERY OVER KS EARLY THIS
MORNING WILL CONTINUE TO CHARGE EASTWARD AND RESULT IN ENTIRE TROUGH
AXIS BECOMING INCREASINGLY NEGATIVELY TILTED TODAY INTO TONIGHT. AS
THIS OCCURS THE NORTH-SOUTH AXIS OF LIGHT-MODERATE SNOW EXTENDING
FROM WESTERN WI SOUTH INTO MISSOURI AT 09Z IS LIKELY TO GRADUALLY
BECOME RE-ORIENTED INTO A MORE NW-SE AXIS AS IT SHIFTS SLOWLY
EASTWARD. THE RE-ORIENTATION THATS EXPECTED TO TAKE PLACE WILL
RESULT IN A DECELERATION OF THE EASTWARD PROGRESSION OF THE SNOW
OVER NORTHWEST ILLINOIS AND STILL ANTICIPATE IT BEING LATE MORNING
BEFORE SNOW BREAKS OUT IN METRO CHICAGO AND POSSIBLY NOT TIL MID
MORNING AS FAR WEST AS ROCKFORD.
AS HAS BEEN NOTED FOR A COUPLE DAYS NOW...THE SYSTEM WILL NOT HAVE
AN ABUNDANCE OF MOISTURE TO WORK WITH HOWEVER WHAT IT LACKS IN
MOISTURE IT LOOKS TO MAKE UP FOR IN FORCING AND DURATION. AS THE
INTENSE COMPACT CLOSED LOW PLOWS EAST ITS PROGGED TO DEEPEN TODAY
RESULTING IN VERY IMPRESSIVE 12HR/500MB HEIGHT FALLS OVER 200DM VERY
DEEP MODERATE ASCENT EXPECTED. SYNOPTICALLY STILL APPEARS AS THOUGH
QPF ACROSS THE CWA WILL BE FAIRLY UNIFORM AND SUPPORTIVE OF A SOLID
4-8 INCH SNOWFALL CWA-WIDE. THERMAL PROFILES ARE A BIT WARMER THAN
IN PREVIOUS RUNS RESULTING IN SLIGHTLY LESS FAVORABLY DEEP DENDRITIC
GROWTH ZONE (DGZ) WHICH COULD CUT BACK ON SNOW:LIQUID RATIOS A BIT.
IN ADDITION...THE STRONG WINDS ALSO ARE NOT SUPPORTIVE OF
EXCEPTIONALLY HIGH SNOW:LIQUID RATIOS AND THINK A REASONABLE BALL
PARK GUESS IS THAT THEY WILL GENERALLY END UP IN THE BALLPARK OF
10-15:1.
INTERESTINGLY...SOME OF THE HI-RES MESOSCALE MODELS ARE SUGGESTING
THAT THERE COULD BE SOME MESOSCALE BANDING OF HEAVY SNOW DEVELOPING
BY THIS AFTERNOON OVER PORTIONS OF OUR CWA IN ASSOCIATION WITH
STRENGTHENING LOW LEVEL FRONTOGENETIC CIRCULATION. SHOULD THAT OCCUR
IT WOULD NOT BE AT ALL HARD TO ENVISION A BAND OF SNOWFALL TOTALS IN
8-12 INCH RANGE...PARTICULARLY CLOSE TO PIVOT POINT WHERE HEAVIER
SNOW BAND WILL SIT THE LONGEST AS THE ORIENTATION GOES FROM WNW-ESE
TO MORE NE-SW TONIGHT. REALLY IMPOSSIBLE TO PINPOINT THOSE TYPE OF
MESO-BETA SCALE TYPE PHENOMENA THIS FAR IN ADVANCE SO RATHER THAN
BLANKETING 23 COUNTIES WITH A WARNING WHEN ITD PROBABLY ONLY BE A
FRACTION OF THOSE REACH CRITERIA HAVE OPTED TO LET THE ADVISORY
RIDE WITH 4-8 INCH AMOUNTS AND JUST MENTION LOCALLY HEAVIER TOTALS
IN THE WSW. AS MESOSCALE DETAILS START TO UNFOLD LATER TODAY ITS
POSSIBLE THAT THE DAY SHIFT MAY NEED TO UPGRADE PORTIONS OF THE
ADVISORY TO A WARNING.
HAVE OPTED TO UPGRADE PORTER COUNTY INDIANA TO A WARNING...AS LOW
LEVEL TRAJECTORIES COULD ALLOW FOR A PERIOD OF LAKE ENHANCED
SNOWFALL THIS AFTERNOON. THE WINDOW OF OPPORTUNITY FOR LAKE
ENHANCEMENT FOR NE PORTER LOOKS SMALL AS CONDITIONS ARE LIKELY TO
BECOMING INCREASINGLY SUPPORTIVE OF LAKE ENHANCEMENT THIS AFTERNOON
BUT AT THE SAME TIME WINDS WILL BE BACKING WHICH SHOULD SENDING ANY
THREAT OF LAKE ENHANCEMENT EAST INTO IWX-LAND. BEFORE THAT OCCURS
SEEMS PLAUSIBLE THAT THE OCCURS COULD EASILY SEE NE PORTER PICKING
UP A COUPLE BONUS INCHES OF SNOW OFF THE LAKE.
SNOW LOOKS TO START WINDING DOWN AFTER MIDNIGHT AND ENDING
EVERYWHERE BY MID-LATE MORNING FRIDAY. NO CHANGES PLANNED TO THE
TIMING OF THE HEADLINES. WITH WINDS LIKELY TO GUST TO OVER 30 MPH
THIS AFTERNOON AND TONIGHT BLOWING AND DRIFTING SNOW WILL LIKELY BE
AN ISSUE WITH THIS STORM...PARTICULARLY TONIGHT AS SNOW BECOMES
FLUFFIER INCREASING ITS "BLOW-ABILITY".
IZZI
IN-BETWEEN TERM (FRIDAY NIGHT THROUGH SATURDAY NIGHT)...
IN THE WAKE OF THE STORM FOCUS WILL TURN TO TEMPS FRIDAY
NIGHT...WHICH WILL ULTIMATELY BE CLOSELY TIED TO HOW MUCH (IF ANY
CLEARING) WE SEE. MODELS ALL SUGGEST THAT STRATUS WILL CLEAR OUT
FRIDAY EVENING...BUT MODELS ARE ALSO NOTORIOUS FOR BREAKING STRATUS
UP TOO QUICKLY. SUSPECT THAT THERE IS A VERY REAL CHANCE THAT THE
STRATUS MAY NOT CLEAR OUT AT ALL BEFORE CLOUDINESS WITH SATURDAY`S
CLIPPER ARRIVES LATE FRIDAY NIGHT INTO SAT MORNING. GIVEN THE LOW
CONFIDENCE AT THIS DISTANCE HAVE TAKEN A CONSERVATIVE/MIDDLE OF THE
ROAD APPROACH TO TEMPS. ON THE ONE EXTREME...IF SKIES CLEAR OUT
WITH THE SURFACE RIDGE AXIS APPROACHING ITS A VERY REAL
POSSIBILITY THAT LOWS COULD DROP TO BETWEEN ZERO TO
-10...PARTICULARLY OVER NORTH CENTRAL ILLINOIS. CONVERSELY...IF
STRATUS HANGS ON TEMPS MAY END UP MOST IN THE LOW TO MID
TEENS...WHICH I SUSPECT IS PROBABLY THE MORE LIKELY SCENARIO.
BY SATURDAY A FAST MOVING CLIPPER IS PROGGED TO ZIP SOUTHEASTWARD
ACROSS THE MIDWEST. NOT AN OVERLY STRONG SYSTEM AND WILL BE MOISTURE
STARVED...BUT WITH PERSISTENT WARM AIR ADVECTION MIGHT BE ABLE TO
LAY DOWN A BAND OF AN INCH OR SO OF SNOW. MODELS GENERALLY TRACK
SURFACE LOW FROM NORTHERN IOWA INTO SOUTHERN ILLINOIS WHICH WOULD
FAVOR OUR WESTERN CWA FOR HIGHEST CHANCES OF SNOW. HAVE TRENDED POPS
UP IN THE GRIDS AGAIN...WELL ABOVE MOS GUIDANCE AND MORE IN LINE
WITH HPC QPF FORECAST OF GREATER THAN A TENTH OF AN INCH. CLIPPER
SHOULD BE OUT OF THE AREA BY LATER SATURDAY EVENING WITH CLOUDS
PROBABLY STICKING AROUND AND KEEPING TEMPS SOMEWHAT IN CHECK
SATURDAY NIGHT.
IZZI
LONG TERM (SUNDAY THROUGH WEDNESDAY)...
THE POLAR JET WHICH HAD BEEN ANCHORED TO OUR NORTH MUCH OF THE
WINTER WILL BE MORE PRESENT OVER THE MID-SECTION OF THE COUNTRY.
THIS SEEMS TIED TO A MORE ORGANIZED POLAR VORTEX DEVELOPING OVER
NORTHERN CANADA/BAFFIN ISLAND...A FEATURE CONDUCIVE FOR STEERING
COLD AIR PERIODS INTO CENTRAL CANADA AND OFTEN THE EASTERN HALF OF
THE U.S. THAT SAID...A RECOVERY FROM OUR IMMEDIATE COLD AIR SNAP
WILL BE SEEN AT THE START OF NEXT WEEK WITH 850 MB TEMPERATURES
RETURNING TO ABOVE ZERO BY MONDAY WITHIN DEEP SOUTHWEST FLOW. THE
PATTERN ACTUALLY WILL BRIEFLY RESEMBLE MUCH OF THE PAST
MONTH...HOWEVER ANTICIPATED SNOW COVER ON THE GROUND THROUGHOUT THE
REGION SHOULD KEEP THE NEAR-SURFACE AIR MASS COOLER THAN WHAT WE
HAVE SEEN RECENTLY WITH THE SAME TYPE OF AIR MASS. IN
ADDITION...MORE COLUMN MOISTURE IS PROJECTED IN ALL LONG RANGE
GUIDANCE DURING MONDAY...A HINT AT STRATUS WHICH WOULD BE MORE
FAVORED WITH MOIST AND MILD RETURN FLOW OVER SNOW COVER. HAVE GUIDED
MORE TOWARDS A BLEND OF RAW GUIDANCE FOR HIGHS AS OPPOSED TO THE
BIAS-CORRECTED WHICH HAS WORKED SO WELL FOR HIGH TEMPERATURES THE
PAST MONTH TO MONTH AND A HALF. FOR SUN NIGHT AND MON NIGHT HAVE
TRENDED TOWARDS THE MILDER BIAS-CORRECTED FORECASTS.
A COLD FRONT IS EXPECTED TO WORK THROUGH SOMETIME MONDAY NIGHT OR
TUESDAY...WITH A POTENTIAL LOW DEVELOPING ALONG IT DURING THAT
PERIOD. A MEAN SOLUTION ON THE MODELS HAS A LOW TRACKING NEAR OR
JUST TO THE WEST OF THE AREA. THIS WOULD AT LEAST INTRODUCE
THICKNESSES SUPPORTIVE OF RAIN/DRIZZLE DURING MONDAY AND MONDAY
NIGHT IN ANY PRECIPITATION THAT FALLS...AND THE CHANCE FOR
POTENTIALLY RAIN CHANGING TO SNOW LATER ON. SLOWER HAS BEEN BETTER
WITH SYSTEMS RECENTLY...AND THE 12.00 EC SLOWED EVEN FURTHER FROM
ITS PRECEDING RUN. CONFIDENCE IN THIS PERIOD IS LOW THOUGH WITH A
LOW DEVELOPING ALONG A FRONT WITH A SYSTEM THAT IS STILL WELL
OFFSHORE THE WEST COAST. INTERESTINGLY ENOUGH...DEW POINTS ARE
FORECAST TO CREEP UP TO THE MID 30S TO POSSIBLY LOWER 40S IN THE
FORECAST AREA...WHICH COMBINED WITH ANY RAIN/DRIZZLE WOULD LEAD TO
QUICK SNOW MELT AND POSSIBLY ADVECTION FOG.
BEYOND...BOTH THE 12.00 GFS AND EC HAVE THE NEXT COLD AIR DOME BUILT
IN SOUTHERN CANADA BY MIDWEEK WITH 850 MB TEMPS OF -30C OR COLDER.
THEY BOTH DIFFER VASTLY FROM RUN TO RUN IN HOW FAR SOUTH AND EAST
AND HOW QUICKLY THIS EVOLVES...AND WHETHER OR NOT IT WILL EVEN GET
HERE. THE JET LOOKS TO REMAIN ACTIVE AS WELL...SO CONFIDENCE IN THIS
PERIOD IS LOW.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST/NORTHWEST WINDS SLOWLY INCREASING THROUGH THE REMAINDER OF
THE AFTERNOON WITH THE STRONGER GUSTS EXPECTED LATE THIS
AFTERNOON/EARLY EVENING.
* PREVAILING IFR CEILINGS STILL EXPECTED THROUGH THE REMAINDER OF
THE DAY/NIGHT.
* LIGHT TO MODERATE SNOW TO CONTINUE THIS AFTERNOON WITH PERIODS
OF HEAVIER SNOW STILL POSSIBLE. VIS OF 1/2SM EXPECTED WITH
PERIODS OF 1/4SM.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
LARGE AREA OF LIGHT TO MODERATE SNOW CONTINUES TO DEVELOP AND
SLOWLY MOVE ACROSS THE TERMINALS EARLY THIS AFTERNOON AS LARGE
SCALE FORCING MOVES THROUGH THE REGION. EXPECT THIS LIGHT TO
MODERATE SNOW TO PERSIST INTO THE AFTERNOON AND EVEN EXPECT AN
INCREASE IN INTENSITY WITH PERIODS OF HEAVY SNOW POSSIBLE. VIS
LOOKS TO HOLD AROUND 1/2SM WITH PERIODS OF 1/4SM POSSIBLE LATER
THIS AFTERNOON. THIS PERIOD OF HEAVIER SNOW IS EXPECTED TO
CONTINUE INTO THE EARLY AFTERNOON AND EARLY EVENING WITH SNOWFALL
RATES ALSO BECOMING AN ISSUE. LATER THIS EVENING...LIGHT TO
MODERATE SNOW CAN STILL BE EXPECTED WITH SOME UNCERTAINTY AS TO IF
ANOTHER PERIOD OF HEAVIER SNOW COULD BE OBSERVED. WILL CONTINUE TO
MONITOR LATEST TRENDS AND ADJUST ACCORDINGLY FOR THE EARLY EVENING
TIME FRAME. THEN EXPECT THE HEAVIEST SNOW TO START SHIFTING EAST
LATE IN THE EVENING. CEILINGS ARE LOCKED IN AT IFR AND WILL REMAIN
FOR THE REMAINDER OF TODAY AND TONIGHT...BEFORE A SLOW UPWARD
TRENDS TO MVFR BY MID TO LATE MORNING ON FRIDAY AS THIS SYSTEM
SLOWLY TRANSITIONS TO THE EAST.
WEST/NORTHWEST WINDS HAVE BEEN SLOW TO INCREASE TODAY BUT STILL
EXPECT THEM TO INCREASE LATER THIS AFTERNOON AND EVENING.
WINDS/GUSTS WILL INCREASE TO AROUND THE 25KT RANGE DURING THAT
TIME WITH A MORE NORTHWEST WIND EXPECTED AS SURFACE TROUGH PUSHES
THROUGH. WEST/NORTHWEST WINDS WILL THEN SLOWLY DIMINISH FRIDAY
MORNING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.
* MEDIUM HIGH CONFIDENCE WITH CEILINGS AND TRENDS TODAY/TONIGHT.
* MEDIUM HIGH CONFIDENCE WITH SNOW/VIS TRENDS TODAY...WITH MEDIUM
CONFIDENCE OF SNOW/VIS TRENDS TONIGHT INTO EARLY FRIDAY MORNING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...CHANCE OF SNOW WITH MVFR OR IFR CIGS/VIS DEVELOPING BY
THE AFTERNOON AND CONTINUING INTO THE NIGHT.
SUNDAY...VFR. WX NIL.
MONDAY...IFR CIGS/VIS IN DRIZZLE OR LIGHT RAIN.
TUESDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS.
WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
335 PM CST
LOW PRESSURE OF OVER THE FAR SOUTH END OF LAKE HURON AT MID
AFTERNOON DEEPENS AS IT MOVES EAST OVER THE LOWER GREAT LAKES
TONIGHT...AND THEN NORTHEAST UP THE ST. LAWRENCE VALLEY ON
FRIDAY. MEANWHILE...HIGH PRESSURE WILL GRADUALLY MOVE FROM
MANITOBA TO WESTERN ONTARIO. THE STRONG PRESSURE GRADIENT BETWEEN
THE LOW AND THE HIGH...ALONG WITH A SURGE OF COLD AIR...WILL
RESULT IN GALE FORCE WINDS TONIGHT AND INTO FRIDAY AFTERNOON.
WINDS WILL BEGIN TO RELAX LATER FRIDAY AS THE LOW MOVES FARTHER
AWAY AND HIGH PRESSURE MOVES SOUTHEAST ACROSS ONTARIO. LOW
PRESSURE OF MOVES SOUTHEAST ACROSS THE CANADIAN PRAIRIE
PROVIDENCES FRIDAY NIGHT BUT THEN WEAKENS AS IT CONTINUES ON TO
THE UPPER GREAT LAKES SATURDAY. ANOTHER LOW WILL MOVE EAST ACROSS
SOUTH CENTRAL CANADA SATURDAY NIGHT THROUGH SUNDAY NIGHT...THEN
TURN NORTHEASTWARD AND REACH JAMES BAY MONDAY NIGHT. DEPENDING ON
THE STRENGTH OF THIS LOW IT COULD POTENTIALLY PRODUCE GALES
TUESDAY AND TUESDAY NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-
ILZ022 UNTIL 9 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-
ILZ019-ILZ021-ILZ032 UNTIL 4 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 AM FRIDAY.
IN...WINTER STORM WARNING...INZ001-INZ002 UNTIL 9 AM FRIDAY.
WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 AM FRIDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL
MIDNIGHT SATURDAY.
GALE WARNING...LMZ744-LMZ745...9 PM THURSDAY TO 3 PM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
224 PM CST THU JAN 12 2012
.DISCUSSION...
134 PM CST
LIGHT TO MODERATE SNOWFALL CONTINUES ACROSS THE AREA EARLY THIS
AFTERNOON. RADAR TRENDS AND SHORT TERM GUIDANCE SHOW TWO AREAS OF
BETTER FORCING WITHIN THE BROAD LIFT. THE FIRST IS ORIENTED FROM
BENTON HARBOR MICHIGAN NORTHWEST ACROSS MILWAUKEE WITH A SECOND
STARTING TO TAKE SHAPE FROM RENSSELAER TO PRINCETON TO SAVANNA. IN
BETWEEN...RADAR RETURNS HAVE EASED OFF SOMEWHAT BUT SNOWFALL
CONTINUES. OVERALL NEAR TERM TRENDS SUGGEST THAT
FORCING/FRONTOGENESIS WILL BECOME MORE FOCUSED OVER THE CWA INTO
LATE AFTERNOON...WITH PERHAPS THE MOST FOCUSED FORCING OVER NE
IL/NW IN EARLY THIS EVENING.
IN ADDITION...LOW LEVEL AREA OF CONVERGENCE OVER THE LAKE
CONTINUES TO COMPLICATE NEAR TERM DETAILS. LATEST RUC SHOWS AN
EAST-WEST BAND OF CONVERGENCE FROM THE LAKE/COOK IL BORDER
EASTWARD. THIS TROUGH IS NOT SO EVIDENT IN SHORE OBS BUT ORD TDWR
SHOWS A SOUTHWESTWARD MOVING AREA OF ENHANCED REFLECTIVITY MOVING
INLAND FROM EVANSTON SOUTHWARD INTO DOWNTOWN CHICAGO. LAKE
INFLUENCE WILL LIKELY BE RATHER TRANSIENT BUT IS SEEMINGLY ABLE TO
OCCUR...AND MAY BECOME MORE FAVORED AS LOW-LEVEL THERMAL PROFILES
COOL. THE EXTENT TO WHICH IT OCCURS IS STILL NOT CLEAR BUT AREAS
ALONG THE COOK COUNTY IL SHORE SEEM MOST FAVORED INTO MID
AFTERNOON BEFORE IT PIVOTS INTO NORTHWEST INDIANA LATE THIS
AFTERNOON/EARLY THIS EVENING.
MDB
//PREV DISCUSSION...
1110 AM CST
HAVE OPTED TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER
STORM WARNING FOR MUCH OF NORTHEAST IL AND NORTHWEST IN. RADAR
TRENDS SHOW THE MAIN BAND OF SNOW INTENSIFYING AND BECOMING MORE
WIDESPREAD ACROSS MUCH OF THE FORECAST AREA AS IT LIFT
NORTHEASTWARD AND BEGINS TO PIVOT COUNTER-CLOCKWISE.
FRONTOGENETICAL FORCING BECOME BETTER FOCUSED AS MID LEVEL TROUGH
SWINGS ACROSS THE AREA BRINGING IN WARM ADVECTION FROM THE EAST
AND COLD ADVECTION FROM THE WEST. IN ADDITION...FOCUSING MAY BE
FURTHER ENHANCED BY THE PRESENCE OF A MID LEVEL TROUGH OF WARM AIR
ALOFT. THIS SYNOPTIC FORCING BY ITSELF SUGGESTS THAT SNOWFALL
RATES WILL BE HIGHER FROM MID AFTERNOON THROUGH EARLY EVENING
RESULTING IN 4-8 INCH TOTALS IN A SHORTER AMOUNT OF TIME. IN
ADDITION LAKE ENHANCEMENT IN SOME FORM STILL LOOKS POSSIBLE LATE
THIS AFTERNOON...BUT WILL BE VERY CHALLENGING TO PIN DOWN. SURFACE
OBS AROUND THE SOUTHERN SHORE STILL SHOW SIGNS OF A CIRCULATION
WITH RADAR SHOWING A NORTHWEST-SOUTHEAST ORIENTED BAND OF PRECIP
WHICH MAY BE REFLECTIVE MORE OF A ELONGATED CONVERGENCE AREA.
SEVERAL RECENT RUNS OF THE RUC/HRRR SHOW A CLOSED CIRCULATION
SHIFTING WESTWARD TOWARD THE IL SHORE THIS AFTERNOON WITH OTHER
GUIDANCE SHOWING AT LEAST SOME SORT OF SHORELINE CONVERGENCE
DEVELOPING. THE CHALLENGE WILL BE FOR THIS TO CONTINUE IN THE
MIDST OF INCREASING NORTHWESTERLY LOW LEVEL FLOW...WHICH HAS BEEN
SLOWER TO ADVANCE EASTWARD. SHOULD THIS LAKE ENHANCEMENT/BANDING
OCCUR...AND THIS IS STILL UNCERTAIN...THEN SOME AREAS COULD EASILY
SEE 8-10 INCHES OR POSSIBLY MORE BUT THIS WOULD LIKELY BE VERY
LOCALIZED. EVEN WITHOUT LAKE ENHANCEMENT SNOWFALL RATES ARE
EXPECTED TO BE HEAVIEST DURING THE AFTERNOON/EVENING RUSH
HOUR...WITH IMPACTS MAGNIFIED UNDER ANY LAKE BANDS. GUSTY WINDS
WILL SPREAD IN FROM THE WEST THROUGH THE AFTERNOON ACROSS NORTH
CENTRAL ILLINOIS AND INTO THE CHICAGO METRO LATE THIS
AFTERNOON/EARLY THIS EVENING AND THEN INTO NW INDIANA.
MDB
//PREV DISCUSSION...
309 AM CST
NEAR TERM (NOW THROUGH FRIDAY)...
VERY LITTLE CHANGE FROM PREVIOUS FORECAST WITH ONLY REAL ADJUSTMENT
BEING UPGRADING TO A WARNING FOR PORTER COUNTY DUE TO SOME LAKE
ENHANCEMENT THIS AFTERNOON POSSIBLY INTO VERY EARLY THIS EVENING.
POTENT VORT MAX EVIDENT ON WATER VAPOR IMAGERY OVER KS EARLY THIS
MORNING WILL CONTINUE TO CHARGE EASTWARD AND RESULT IN ENTIRE TROUGH
AXIS BECOMING INCREASINGLY NEGATIVELY TILTED TODAY INTO TONIGHT. AS
THIS OCCURS THE NORTH-SOUTH AXIS OF LIGHT-MODERATE SNOW EXTENDING
FROM WESTERN WI SOUTH INTO MISSOURI AT 09Z IS LIKELY TO GRADUALLY
BECOME RE-ORIENTED INTO A MORE NW-SE AXIS AS IT SHIFTS SLOWLY
EASTWARD. THE RE-ORIENTATION THATS EXPECTED TO TAKE PLACE WILL
RESULT IN A DECELERATION OF THE EASTWARD PROGRESSION OF THE SNOW
OVER NORTHWEST ILLINOIS AND STILL ANTICIPATE IT BEING LATE MORNING
BEFORE SNOW BREAKS OUT IN METRO CHICAGO AND POSSIBLY NOT TIL MID
MORNING AS FAR WEST AS ROCKFORD.
AS HAS BEEN NOTED FOR A COUPLE DAYS NOW...THE SYSTEM WILL NOT HAVE
AN ABUNDANCE OF MOISTURE TO WORK WITH HOWEVER WHAT IT LACKS IN
MOISTURE IT LOOKS TO MAKE UP FOR IN FORCING AND DURATION. AS THE
INTENSE COMPACT CLOSED LOW PLOWS EAST ITS PROGGED TO DEEPEN TODAY
RESULTING IN VERY IMPRESSIVE 12HR/500MB HEIGHT FALLS OVER 200DM VERY
DEEP MODERATE ASCENT EXPECTED. SYNOPTICALLY STILL APPEARS AS THOUGH
QPF ACROSS THE CWA WILL BE FAIRLY UNIFORM AND SUPPORTIVE OF A SOLID
4-8 INCH SNOWFALL CWA-WIDE. THERMAL PROFILES ARE A BIT WARMER THAN
IN PREVIOUS RUNS RESULTING IN SLIGHTLY LESS FAVORABLY DEEP DENDRITIC
GROWTH ZONE (DGZ) WHICH COULD CUT BACK ON SNOW:LIQUID RATIOS A BIT.
IN ADDITION...THE STRONG WINDS ALSO ARE NOT SUPPORTIVE OF
EXCEPTIONALLY HIGH SNOW:LIQUID RATIOS AND THINK A REASONABLE BALL
PARK GUESS IS THAT THEY WILL GENERALLY END UP IN THE BALLPARK OF
10-15:1.
INTERESTINGLY...SOME OF THE HI-RES MESOSCALE MODELS ARE SUGGESTING
THAT THERE COULD BE SOME MESOSCALE BANDING OF HEAVY SNOW DEVELOPING
BY THIS AFTERNOON OVER PORTIONS OF OUR CWA IN ASSOCIATION WITH
STRENGTHENING LOW LEVEL FRONTOGENETIC CIRCULATION. SHOULD THAT OCCUR
IT WOULD NOT BE AT ALL HARD TO ENVISION A BAND OF SNOWFALL TOTALS IN
8-12 INCH RANGE...PARTICULARLY CLOSE TO PIVOT POINT WHERE HEAVIER
SNOW BAND WILL SIT THE LONGEST AS THE ORIENTATION GOES FROM WNW-ESE
TO MORE NE-SW TONIGHT. REALLY IMPOSSIBLE TO PINPOINT THOSE TYPE OF
MESO-BETA SCALE TYPE PHENOMENA THIS FAR IN ADVANCE SO RATHER THAN
BLANKETING 23 COUNTIES WITH A WARNING WHEN ITD PROBABLY ONLY BE A
FRACTION OF THOSE REACH CRITERIA HAVE OPTED TO LET THE ADVISORY
RIDE WITH 4-8 INCH AMOUNTS AND JUST MENTION LOCALLY HEAVIER TOTALS
IN THE WSW. AS MESOSCALE DETAILS START TO UNFOLD LATER TODAY ITS
POSSIBLE THAT THE DAY SHIFT MAY NEED TO UPGRADE PORTIONS OF THE
ADVISORY TO A WARNING.
HAVE OPTED TO UPGRADE PORTER COUNTY INDIANA TO A WARNING...AS LOW
LEVEL TRAJECTORIES COULD ALLOW FOR A PERIOD OF LAKE ENHANCED
SNOWFALL THIS AFTERNOON. THE WINDOW OF OPPORTUNITY FOR LAKE
ENHANCEMENT FOR NE PORTER LOOKS SMALL AS CONDITIONS ARE LIKELY TO
BECOMING INCREASINGLY SUPPORTIVE OF LAKE ENHANCEMENT THIS AFTERNOON
BUT AT THE SAME TIME WINDS WILL BE BACKING WHICH SHOULD SENDING ANY
THREAT OF LAKE ENHANCEMENT EAST INTO IWX-LAND. BEFORE THAT OCCURS
SEEMS PLAUSIBLE THAT THE OCCURS COULD EASILY SEE NE PORTER PICKING
UP A COUPLE BONUS INCHES OF SNOW OFF THE LAKE.
SNOW LOOKS TO START WINDING DOWN AFTER MIDNIGHT AND ENDING
EVERYWHERE BY MID-LATE MORNING FRIDAY. NO CHANGES PLANNED TO THE
TIMING OF THE HEADLINES. WITH WINDS LIKELY TO GUST TO OVER 30 MPH
THIS AFTERNOON AND TONIGHT BLOWING AND DRIFTING SNOW WILL LIKELY BE
AN ISSUE WITH THIS STORM...PARTICULARLY TONIGHT AS SNOW BECOMES
FLUFFIER INCREASING ITS "BLOW-ABILITY".
IZZI
IN-BETWEEN TERM (FRIDAY NIGHT THROUGH SATURDAY NIGHT)...
IN THE WAKE OF THE STORM FOCUS WILL TURN TO TEMPS FRIDAY
NIGHT...WHICH WILL ULTIMATELY BE CLOSELY TIED TO HOW MUCH (IF ANY
CLEARING) WE SEE. MODELS ALL SUGGEST THAT STRATUS WILL CLEAR OUT
FRIDAY EVENING...BUT MODELS ARE ALSO NOTORIOUS FOR BREAKING STRATUS
UP TOO QUICKLY. SUSPECT THAT THERE IS A VERY REAL CHANCE THAT THE
STRATUS MAY NOT CLEAR OUT AT ALL BEFORE CLOUDINESS WITH SATURDAY`S
CLIPPER ARRIVES LATE FRIDAY NIGHT INTO SAT MORNING. GIVEN THE LOW
CONFIDENCE AT THIS DISTANCE HAVE TAKEN A CONSERVATIVE/MIDDLE OF THE
ROAD APPROACH TO TEMPS. ON THE ONE EXTREME...IF SKIES CLEAR OUT
WITH THE SURFACE RIDGE AXIS APPROACHING ITS A VERY REAL
POSSIBILITY THAT LOWS COULD DROP TO BETWEEN ZERO TO
-10...PARTICULARLY OVER NORTH CENTRAL ILLINOIS. CONVERSELY...IF
STRATUS HANGS ON TEMPS MAY END UP MOST IN THE LOW TO MID
TEENS...WHICH I SUSPECT IS PROBABLY THE MORE LIKELY SCENARIO.
BY SATURDAY A FAST MOVING CLIPPER IS PROGGED TO ZIP SOUTHEASTWARD
ACROSS THE MIDWEST. NOT AN OVERLY STRONG SYSTEM AND WILL BE MOISTURE
STARVED...BUT WITH PERSISTENT WARM AIR ADVECTION MIGHT BE ABLE TO
LAY DOWN A BAND OF AN INCH OR SO OF SNOW. MODELS GENERALLY TRACK
SURFACE LOW FROM NORTHERN IOWA INTO SOUTHERN ILLINOIS WHICH WOULD
FAVOR OUR WESTERN CWA FOR HIGHEST CHANCES OF SNOW. HAVE TRENDED POPS
UP IN THE GRIDS AGAIN...WELL ABOVE MOS GUIDANCE AND MORE IN LINE
WITH HPC QPF FORECAST OF GREATER THAN A TENTH OF AN INCH. CLIPPER
SHOULD BE OUT OF THE AREA BY LATER SATURDAY EVENING WITH CLOUDS
PROBABLY STICKING AROUND AND KEEPING TEMPS SOMEWHAT IN CHECK
SATURDAY NIGHT.
IZZI
LONG TERM (SUNDAY THROUGH WEDNESDAY)...
THE POLAR JET WHICH HAD BEEN ANCHORED TO OUR NORTH MUCH OF THE
WINTER WILL BE MORE PRESENT OVER THE MID-SECTION OF THE COUNTRY.
THIS SEEMS TIED TO A MORE ORGANIZED POLAR VORTEX DEVELOPING OVER
NORTHERN CANADA/BAFFIN ISLAND...A FEATURE CONDUCIVE FOR STEERING
COLD AIR PERIODS INTO CENTRAL CANADA AND OFTEN THE EASTERN HALF OF
THE U.S. THAT SAID...A RECOVERY FROM OUR IMMEDIATE COLD AIR SNAP
WILL BE SEEN AT THE START OF NEXT WEEK WITH 850 MB TEMPERATURES
RETURNING TO ABOVE ZERO BY MONDAY WITHIN DEEP SOUTHWEST FLOW. THE
PATTERN ACTUALLY WILL BRIEFLY RESEMBLE MUCH OF THE PAST
MONTH...HOWEVER ANTICIPATED SNOW COVER ON THE GROUND THROUGHOUT THE
REGION SHOULD KEEP THE NEAR-SURFACE AIR MASS COOLER THAN WHAT WE
HAVE SEEN RECENTLY WITH THE SAME TYPE OF AIR MASS. IN
ADDITION...MORE COLUMN MOISTURE IS PROJECTED IN ALL LONG RANGE
GUIDANCE DURING MONDAY...A HINT AT STRATUS WHICH WOULD BE MORE
FAVORED WITH MOIST AND MILD RETURN FLOW OVER SNOW COVER. HAVE GUIDED
MORE TOWARDS A BLEND OF RAW GUIDANCE FOR HIGHS AS OPPOSED TO THE
BIAS-CORRECTED WHICH HAS WORKED SO WELL FOR HIGH TEMPERATURES THE
PAST MONTH TO MONTH AND A HALF. FOR SUN NIGHT AND MON NIGHT HAVE
TRENDED TOWARDS THE MILDER BIAS-CORRECTED FORECASTS.
A COLD FRONT IS EXPECTED TO WORK THROUGH SOMETIME MONDAY NIGHT OR
TUESDAY...WITH A POTENTIAL LOW DEVELOPING ALONG IT DURING THAT
PERIOD. A MEAN SOLUTION ON THE MODELS HAS A LOW TRACKING NEAR OR
JUST TO THE WEST OF THE AREA. THIS WOULD AT LEAST INTRODUCE
THICKNESSES SUPPORTIVE OF RAIN/DRIZZLE DURING MONDAY AND MONDAY
NIGHT IN ANY PRECIPITATION THAT FALLS...AND THE CHANCE FOR
POTENTIALLY RAIN CHANGING TO SNOW LATER ON. SLOWER HAS BEEN BETTER
WITH SYSTEMS RECENTLY...AND THE 12.00 EC SLOWED EVEN FURTHER FROM
ITS PRECEDING RUN. CONFIDENCE IN THIS PERIOD IS LOW THOUGH WITH A
LOW DEVELOPING ALONG A FRONT WITH A SYSTEM THAT IS STILL WELL
OFFSHORE THE WEST COAST. INTERESTINGLY ENOUGH...DEW POINTS ARE
FORECAST TO CREEP UP TO THE MID 30S TO POSSIBLY LOWER 40S IN THE
FORECAST AREA...WHICH COMBINED WITH ANY RAIN/DRIZZLE WOULD LEAD TO
QUICK SNOW MELT AND POSSIBLY ADVECTION FOG.
BEYOND...BOTH THE 12.00 GFS AND EC HAVE THE NEXT COLD AIR DOME BUILT
IN SOUTHERN CANADA BY MIDWEEK WITH 850 MB TEMPS OF -30C OR COLDER.
THEY BOTH DIFFER VASTLY FROM RUN TO RUN IN HOW FAR SOUTH AND EAST
AND HOW QUICKLY THIS EVOLVES...AND WHETHER OR NOT IT WILL EVEN GET
HERE. THE JET LOOKS TO REMAIN ACTIVE AS WELL...SO CONFIDENCE IN THIS
PERIOD IS LOW.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST/NORTHWEST WINDS SLOWLY INCREASING THROUGH THE REMAINDER OF
THE AFTERNOON WITH THE STRONGER GUSTS EXPECTED LATE THIS
AFTERNOON/EARLY EVENING.
* PREVAILING IFR CEILINGS STILL EXPECTED THROUGH THE REMAINDER OF
THE DAY/NIGHT.
* LIGHT TO MODERATE SNOW TO CONTINUE THIS AFTERNOON WITH PERIODS
OF HEAVIER SNOW STILL POSSIBLE. VIS OF 1/2SM EXPECTED WITH
PERIODS OF 1/4SM.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
LARGE AREA OF LIGHT TO MODERATE SNOW CONTINUES TO DEVELOP AND
SLOWLY MOVE ACROSS THE TERMINALS EARLY THIS AFTERNOON AS LARGE
SCALE FORCING MOVES THROUGH THE REGION. EXPECT THIS LIGHT TO
MODERATE SNOW TO PERSIST INTO THE AFTERNOON AND EVEN EXPECT AN
INCREASE IN INTENSITY WITH PERIODS OF HEAVY SNOW POSSIBLE. VIS
LOOKS TO HOLD AROUND 1/2SM WITH PERIODS OF 1/4SM POSSIBLE LATER
THIS AFTERNOON. THIS PERIOD OF HEAVIER SNOW IS EXPECTED TO
CONTINUE INTO THE EARLY AFTERNOON AND EARLY EVENING WITH SNOWFALL
RATES ALSO BECOMING AN ISSUE. LATER THIS EVENING...LIGHT TO
MODERATE SNOW CAN STILL BE EXPECTED WITH SOME UNCERTAINTY AS TO IF
ANOTHER PERIOD OF HEAVIER SNOW COULD BE OBSERVED. WILL CONTINUE TO
MONITOR LATEST TRENDS AND ADJUST ACCORDINGLY FOR THE EARLY EVENING
TIME FRAME. THEN EXPECT THE HEAVIEST SNOW TO START SHIFTING EAST
LATE IN THE EVENING. CEILINGS ARE LOCKED IN AT IFR AND WILL REMAIN
FOR THE REMAINDER OF TODAY AND TONIGHT...BEFORE A SLOW UPWARD
TRENDS TO MVFR BY MID TO LATE MORNING ON FRIDAY AS THIS SYSTEM
SLOWLY TRANSITIONS TO THE EAST.
WEST/NORTHWEST WINDS HAVE BEEN SLOW TO INCREASE TODAY BUT STILL
EXPECT THEM TO INCREASE LATER THIS AFTERNOON AND EVENING.
WINDS/GUSTS WILL INCREASE TO AROUND THE 25KT RANGE DURING THAT
TIME WITH A MORE NORTHWEST WIND EXPECTED AS SURFACE TROUGH PUSHES
THROUGH. WEST/NORTHWEST WINDS WILL THEN SLOWLY DIMINISH FRIDAY
MORNING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.
* MEDIUM HIGH CONFIDENCE WITH CEILINGS AND TRENDS TODAY/TONIGHT.
* MEDIUM HIGH CONFIDENCE WITH SNOW/VIS TRENDS TODAY...WITH MEDIUM
CONFIDENCE OF SNOW/VIS TRENDS TONIGHT INTO EARLY FRIDAY MORNING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...CHANCE OF SNOW WITH MVFR OR IFR CIGS/VIS DEVELOPING BY
THE AFTERNOON AND CONTINUING INTO THE NIGHT.
SUNDAY...VFR. WX NIL.
MONDAY...IFR CIGS/VIS IN DRIZZLE OR LIGHT RAIN.
TUESDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS.
WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
309 AM CST
A LOW PRESSURE SYSTEM OVER OHIO WILL MOVE INTO MICHIGAN THIS
AFTERNOON AND STRENGTHEN. IN ADDITION...ARCTIC AIR WILL POUR INTO
THE REGION TODAY. BETWEEN THESE TWO COMPONENTS...LOW END GALES WILL
FORM ACROSS LAKE MICHIGAN TODAY. WINDS WILL BE NORTH TO NORTHWEST
ALONG THE LAKE...THEREFORE EXPECTING GALES TO LEAK INTO THE INDIANA
NEARSHORE ZONES AS WELL. UPGRADED THE GALE WATCH TO A GALE WARNING
WITH THIS ISSUANCE. THE LOW QUICKLY MOVES EASTWARD FRIDAY AND HIGH
PRESSURE MOVES IN BEHIND IT FRIDAY NIGHT INTO SATURDAY. WINDS WILL
BECOME WESTERLY AND DIMINISH QUICKLY BEHIND THE LOW...BUT EXPECTING
HIGH WAVES TO PERSIST THROUGH EARLY FRIDAY NIGHT IN THE NEARSHORE
ZONES. A WEAKENING LOW PRESSURE SYSTEM PASSES SOUTH OF THE LAKE
LATE SATURDAY...AND WILL HAVE LITTLE TO NO IMPACT ON THE LAKE.
WINDS REMAIN WEAK THROUGH THE WEEKEND BUT BEGIN TO TURN SOUTHERLY
AND INCREASE SUNDAY EVENING AS THE PRESSURE GRADIENT INCREASES
BETWEEN HIGH PRESSURE OVER THE ATLANTIC COAST AND A DEVELOPING LOW
PRESSURE SYSTEM OVER MANITOBA.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-
ILZ022 UNTIL 9 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-
ILZ019-ILZ021-ILZ032 UNTIL 4 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 AM FRIDAY.
IN...WINTER STORM WARNING...INZ001-INZ002 UNTIL 9 AM FRIDAY.
WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 AM FRIDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL
MIDNIGHT SATURDAY.
GALE WARNING...LMZ744-LMZ745...9 PM THURSDAY TO 3 PM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 PM THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
139 PM CST THU JAN 12 2012
.DISCUSSION...
134 PM CST
LIGHT TO MODERATE SNOWFALL CONTINUES ACROSS THE AREA EARLY THIS
AFTERNOON. RADAR TRENDS AND SHORT TERM GUIDANCE SHOW TWO AREAS OF
BETTER FORCING WITHIN THE BROAD LIFT. THE FIRST IS ORIENTED FROM
BENTON HARBOR MICHIGAN NORTHWEST ACROSS MILWAUKEE WITH A SECOND
STARTING TO TAKE SHAPE FROM RENSSELAER TO PRINCETON TO SAVANNA. IN
BETWEEN...RADAR RETURNS HAVE EASED OFF SOMEWHAT BUT SNOWFALL
CONTINUES. OVERALL NEAR TERM TRENDS SUGGEST THAT
FORCING/FRONTOGENESIS WILL BECOME MORE FOCUSED OVER THE CWA INTO
LATE AFTERNOON...WITH PERHAPS THE MOST FOCUSED FORCING OVER NE
IL/NW IN EARLY THIS EVENING.
IN ADDITION...LOW LEVEL AREA OF CONVERGENCE OVER THE LAKE
CONTINUES TO COMPLICATE NEAR TERM DETAILS. LATEST RUC SHOWS AN
EAST-WEST BAND OF CONVERGENCE FROM THE LAKE/COOK IL BORDER
EASTWARD. THIS TROUGH IS NOT SO EVIDENT IN SHORE OBS BUT ORD TDWR
SHOWS A SOUTHWESTWARD MOVING AREA OF ENHANCED REFLECTIVITY MOVING
INLAND FROM EVANSTON SOUTHWARD INTO DOWNTOWN CHICAGO. LAKE
INFLUENCE WILL LIKELY BE RATHER TRANSIENT BUT IS SEEMINGLY ABLE TO
OCCUR...AND MAY BECOME MORE FAVORED AS LOW-LEVEL THERMAL PROFILES
COOL. THE EXTENT TO WHICH IT OCCURS IS STILL NOT CLEAR BUT AREAS
ALONG THE COOK COUNTY IL SHORE SEEM MOST FAVORED INTO MID
AFTERNOON BEFORE IT PIVOTS INTO NORTHWEST INDIANA LATE THIS
AFTERNOON/EARLY THIS EVENING.
MDB
&&
.PREV DISCUSSION...
1110 AM CST
HAVE OPTED TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER
STORM WARNING FOR MUCH OF NORTHEAST IL AND NORTHWEST IN. RADAR
TRENDS SHOW THE MAIN BAND OF SNOW INTENSIFYING AND BECOMING MORE
WIDESPREAD ACROSS MUCH OF THE FORECAST AREA AS IT LIFT
NORTHEASTWARD AND BEGINS TO PIVOT COUNTER-CLOCKWISE.
FRONTOGENETICAL FORCING BECOME BETTER FOCUSED AS MID LEVEL TROUGH
SWINGS ACROSS THE AREA BRINGING IN WARM ADVECTION FROM THE EAST
AND COLD ADVECTION FROM THE WEST. IN ADDITION...FOCUSING MAY BE
FURTHER ENHANCED BY THE PRESENCE OF A MID LEVEL TROUGH OF WARM AIR
ALOFT. THIS SYNOPTIC FORCING BY ITSELF SUGGESTS THAT SNOWFALL
RATES WILL BE HIGHER FROM MID AFTERNOON THROUGH EARLY EVENING
RESULTING IN 4-8 INCH TOTALS IN A SHORTER AMOUNT OF TIME. IN
ADDITION LAKE ENHANCEMENT IN SOME FORM STILL LOOKS POSSIBLE LATE
THIS AFTERNOON...BUT WILL BE VERY CHALLENGING TO PIN DOWN. SURFACE
OBS AROUND THE SOUTHERN SHORE STILL SHOW SIGNS OF A CIRCULATION
WITH RADAR SHOWING A NORTHWEST-SOUTHEAST ORIENTED BAND OF PRECIP
WHICH MAY BE REFLECTIVE MORE OF A ELONGATED CONVERGENCE AREA.
SEVERAL RECENT RUNS OF THE RUC/HRRR SHOW A CLOSED CIRCULATION
SHIFTING WESTWARD TOWARD THE IL SHORE THIS AFTERNOON WITH OTHER
GUIDANCE SHOWING AT LEAST SOME SORT OF SHORELINE CONVERGENCE
DEVELOPING. THE CHALLENGE WILL BE FOR THIS TO CONTINUE IN THE
MIDST OF INCREASING NORTHWESTERLY LOW LEVEL FLOW...WHICH HAS BEEN
SLOWER TO ADVANCE EASTWARD. SHOULD THIS LAKE ENHANCEMENT/BANDING
OCCUR...AND THIS IS STILL UNCERTAIN...THEN SOME AREAS COULD EASILY
SEE 8-10 INCHES OR POSSIBLY MORE BUT THIS WOULD LIKELY BE VERY
LOCALIZED. EVEN WITHOUT LAKE ENHANCEMENT SNOWFALL RATES ARE
EXPECTED TO BE HEAVIEST DURING THE AFTERNOON/EVENING RUSH
HOUR...WITH IMPACTS MAGNIFIED UNDER ANY LAKE BANDS. GUSTY WINDS
WILL SPREAD IN FROM THE WEST THROUGH THE AFTERNOON ACROSS NORTH
CENTRAL ILLINOIS AND INTO THE CHICAGO METRO LATE THIS
AFTERNOON/EARLY THIS EVENING AND THEN INTO NW INDIANA.
MDB
//PREV DISCUSSION...
309 AM CST
NEAR TERM (NOW THROUGH FRIDAY)...
VERY LITTLE CHANGE FROM PREVIOUS FORECAST WITH ONLY REAL ADJUSTMENT
BEING UPGRADING TO A WARNING FOR PORTER COUNTY DUE TO SOME LAKE
ENHANCEMENT THIS AFTERNOON POSSIBLY INTO VERY EARLY THIS EVENING.
POTENT VORT MAX EVIDENT ON WATER VAPOR IMAGERY OVER KS EARLY THIS
MORNING WILL CONTINUE TO CHARGE EASTWARD AND RESULT IN ENTIRE TROUGH
AXIS BECOMING INCREASINGLY NEGATIVELY TILTED TODAY INTO TONIGHT. AS
THIS OCCURS THE NORTH-SOUTH AXIS OF LIGHT-MODERATE SNOW EXTENDING
FROM WESTERN WI SOUTH INTO MISSOURI AT 09Z IS LIKELY TO GRADUALLY
BECOME RE-ORIENTED INTO A MORE NW-SE AXIS AS IT SHIFTS SLOWLY
EASTWARD. THE RE-ORIENTATION THATS EXPECTED TO TAKE PLACE WILL
RESULT IN A DECELERATION OF THE EASTWARD PROGRESSION OF THE SNOW
OVER NORTHWEST ILLINOIS AND STILL ANTICIPATE IT BEING LATE MORNING
BEFORE SNOW BREAKS OUT IN METRO CHICAGO AND POSSIBLY NOT TIL MID
MORNING AS FAR WEST AS ROCKFORD.
AS HAS BEEN NOTED FOR A COUPLE DAYS NOW...THE SYSTEM WILL NOT HAVE
AN ABUNDANCE OF MOISTURE TO WORK WITH HOWEVER WHAT IT LACKS IN
MOISTURE IT LOOKS TO MAKE UP FOR IN FORCING AND DURATION. AS THE
INTENSE COMPACT CLOSED LOW PLOWS EAST ITS PROGGED TO DEEPEN TODAY
RESULTING IN VERY IMPRESSIVE 12HR/500MB HEIGHT FALLS OVER 200DM VERY
DEEP MODERATE ASCENT EXPECTED. SYNOPTICALLY STILL APPEARS AS THOUGH
QPF ACROSS THE CWA WILL BE FAIRLY UNIFORM AND SUPPORTIVE OF A SOLID
4-8 INCH SNOWFALL CWA-WIDE. THERMAL PROFILES ARE A BIT WARMER THAN
IN PREVIOUS RUNS RESULTING IN SLIGHTLY LESS FAVORABLY DEEP DENDRITIC
GROWTH ZONE (DGZ) WHICH COULD CUT BACK ON SNOW:LIQUID RATIOS A BIT.
IN ADDITION...THE STRONG WINDS ALSO ARE NOT SUPPORTIVE OF
EXCEPTIONALLY HIGH SNOW:LIQUID RATIOS AND THINK A REASONABLE BALL
PARK GUESS IS THAT THEY WILL GENERALLY END UP IN THE BALLPARK OF
10-15:1.
INTERESTINGLY...SOME OF THE HI-RES MESOSCALE MODELS ARE SUGGESTING
THAT THERE COULD BE SOME MESOSCALE BANDING OF HEAVY SNOW DEVELOPING
BY THIS AFTERNOON OVER PORTIONS OF OUR CWA IN ASSOCIATION WITH
STRENGTHENING LOW LEVEL FRONTOGENETIC CIRCULATION. SHOULD THAT OCCUR
IT WOULD NOT BE AT ALL HARD TO ENVISION A BAND OF SNOWFALL TOTALS IN
8-12 INCH RANGE...PARTICULARLY CLOSE TO PIVOT POINT WHERE HEAVIER
SNOW BAND WILL SIT THE LONGEST AS THE ORIENTATION GOES FROM WNW-ESE
TO MORE NE-SW TONIGHT. REALLY IMPOSSIBLE TO PINPOINT THOSE TYPE OF
MESO-BETA SCALE TYPE PHENOMENA THIS FAR IN ADVANCE SO RATHER THAN
BLANKETING 23 COUNTIES WITH A WARNING WHEN ITD PROBABLY ONLY BE A
FRACTION OF THOSE REACH CRITERIA HAVE OPTED TO LET THE ADVISORY
RIDE WITH 4-8 INCH AMOUNTS AND JUST MENTION LOCALLY HEAVIER TOTALS
IN THE WSW. AS MESOSCALE DETAILS START TO UNFOLD LATER TODAY ITS
POSSIBLE THAT THE DAY SHIFT MAY NEED TO UPGRADE PORTIONS OF THE
ADVISORY TO A WARNING.
HAVE OPTED TO UPGRADE PORTER COUNTY INDIANA TO A WARNING...AS LOW
LEVEL TRAJECTORIES COULD ALLOW FOR A PERIOD OF LAKE ENHANCED
SNOWFALL THIS AFTERNOON. THE WINDOW OF OPPORTUNITY FOR LAKE
ENHANCEMENT FOR NE PORTER LOOKS SMALL AS CONDITIONS ARE LIKELY TO
BECOMING INCREASINGLY SUPPORTIVE OF LAKE ENHANCEMENT THIS AFTERNOON
BUT AT THE SAME TIME WINDS WILL BE BACKING WHICH SHOULD SENDING ANY
THREAT OF LAKE ENHANCEMENT EAST INTO IWX-LAND. BEFORE THAT OCCURS
SEEMS PLAUSIBLE THAT THE OCCURS COULD EASILY SEE NE PORTER PICKING
UP A COUPLE BONUS INCHES OF SNOW OFF THE LAKE.
SNOW LOOKS TO START WINDING DOWN AFTER MIDNIGHT AND ENDING
EVERYWHERE BY MID-LATE MORNING FRIDAY. NO CHANGES PLANNED TO THE
TIMING OF THE HEADLINES. WITH WINDS LIKELY TO GUST TO OVER 30 MPH
THIS AFTERNOON AND TONIGHT BLOWING AND DRIFTING SNOW WILL LIKELY BE
AN ISSUE WITH THIS STORM...PARTICULARLY TONIGHT AS SNOW BECOMES
FLUFFIER INCREASING ITS "BLOW-ABILITY".
IZZI
IN-BETWEEN TERM (FRIDAY NIGHT THROUGH SATURDAY NIGHT)...
IN THE WAKE OF THE STORM FOCUS WILL TURN TO TEMPS FRIDAY
NIGHT...WHICH WILL ULTIMATELY BE CLOSELY TIED TO HOW MUCH (IF ANY
CLEARING) WE SEE. MODELS ALL SUGGEST THAT STRATUS WILL CLEAR OUT
FRIDAY EVENING...BUT MODELS ARE ALSO NOTORIOUS FOR BREAKING STRATUS
UP TOO QUICKLY. SUSPECT THAT THERE IS A VERY REAL CHANCE THAT THE
STRATUS MAY NOT CLEAR OUT AT ALL BEFORE CLOUDINESS WITH SATURDAY`S
CLIPPER ARRIVES LATE FRIDAY NIGHT INTO SAT MORNING. GIVEN THE LOW
CONFIDENCE AT THIS DISTANCE HAVE TAKEN A CONSERVATIVE/MIDDLE OF THE
ROAD APPROACH TO TEMPS. ON THE ONE EXTREME...IF SKIES CLEAR OUT
WITH THE SURFACE RIDGE AXIS APPROACHING ITS A VERY REAL
POSSIBILITY THAT LOWS COULD DROP TO BETWEEN ZERO TO
-10...PARTICULARLY OVER NORTH CENTRAL ILLINOIS. CONVERSELY...IF
STRATUS HANGS ON TEMPS MAY END UP MOST IN THE LOW TO MID
TEENS...WHICH I SUSPECT IS PROBABLY THE MORE LIKELY SCENARIO.
BY SATURDAY A FAST MOVING CLIPPER IS PROGGED TO ZIP SOUTHEASTWARD
ACROSS THE MIDWEST. NOT AN OVERLY STRONG SYSTEM AND WILL BE MOISTURE
STARVED...BUT WITH PERSISTENT WARM AIR ADVECTION MIGHT BE ABLE TO
LAY DOWN A BAND OF AN INCH OR SO OF SNOW. MODELS GENERALLY TRACK
SURFACE LOW FROM NORTHERN IOWA INTO SOUTHERN ILLINOIS WHICH WOULD
FAVOR OUR WESTERN CWA FOR HIGHEST CHANCES OF SNOW. HAVE TRENDED POPS
UP IN THE GRIDS AGAIN...WELL ABOVE MOS GUIDANCE AND MORE IN LINE
WITH HPC QPF FORECAST OF GREATER THAN A TENTH OF AN INCH. CLIPPER
SHOULD BE OUT OF THE AREA BY LATER SATURDAY EVENING WITH CLOUDS
PROBABLY STICKING AROUND AND KEEPING TEMPS SOMEWHAT IN CHECK
SATURDAY NIGHT.
IZZI
LONG TERM (SUNDAY THROUGH WEDNESDAY)...
THE POLAR JET WHICH HAD BEEN ANCHORED TO OUR NORTH MUCH OF THE
WINTER WILL BE MORE PRESENT OVER THE MID-SECTION OF THE COUNTRY.
THIS SEEMS TIED TO A MORE ORGANIZED POLAR VORTEX DEVELOPING OVER
NORTHERN CANADA/BAFFIN ISLAND...A FEATURE CONDUCIVE FOR STEERING
COLD AIR PERIODS INTO CENTRAL CANADA AND OFTEN THE EASTERN HALF OF
THE U.S. THAT SAID...A RECOVERY FROM OUR IMMEDIATE COLD AIR SNAP
WILL BE SEEN AT THE START OF NEXT WEEK WITH 850 MB TEMPERATURES
RETURNING TO ABOVE ZERO BY MONDAY WITHIN DEEP SOUTHWEST FLOW. THE
PATTERN ACTUALLY WILL BRIEFLY RESEMBLE MUCH OF THE PAST
MONTH...HOWEVER ANTICIPATED SNOW COVER ON THE GROUND THROUGHOUT THE
REGION SHOULD KEEP THE NEAR-SURFACE AIR MASS COOLER THAN WHAT WE
HAVE SEEN RECENTLY WITH THE SAME TYPE OF AIR MASS. IN
ADDITION...MORE COLUMN MOISTURE IS PROJECTED IN ALL LONG RANGE
GUIDANCE DURING MONDAY...A HINT AT STRATUS WHICH WOULD BE MORE
FAVORED WITH MOIST AND MILD RETURN FLOW OVER SNOW COVER. HAVE GUIDED
MORE TOWARDS A BLEND OF RAW GUIDANCE FOR HIGHS AS OPPOSED TO THE
BIAS-CORRECTED WHICH HAS WORKED SO WELL FOR HIGH TEMPERATURES THE
PAST MONTH TO MONTH AND A HALF. FOR SUN NIGHT AND MON NIGHT HAVE
TRENDED TOWARDS THE MILDER BIAS-CORRECTED FORECASTS.
A COLD FRONT IS EXPECTED TO WORK THROUGH SOMETIME MONDAY NIGHT OR
TUESDAY...WITH A POTENTIAL LOW DEVELOPING ALONG IT DURING THAT
PERIOD. A MEAN SOLUTION ON THE MODELS HAS A LOW TRACKING NEAR OR
JUST TO THE WEST OF THE AREA. THIS WOULD AT LEAST INTRODUCE
THICKNESSES SUPPORTIVE OF RAIN/DRIZZLE DURING MONDAY AND MONDAY
NIGHT IN ANY PRECIPITATION THAT FALLS...AND THE CHANCE FOR
POTENTIALLY RAIN CHANGING TO SNOW LATER ON. SLOWER HAS BEEN BETTER
WITH SYSTEMS RECENTLY...AND THE 12.00 EC SLOWED EVEN FURTHER FROM
ITS PRECEDING RUN. CONFIDENCE IN THIS PERIOD IS LOW THOUGH WITH A
LOW DEVELOPING ALONG A FRONT WITH A SYSTEM THAT IS STILL WELL
OFFSHORE THE WEST COAST. INTERESTINGLY ENOUGH...DEW POINTS ARE
FORECAST TO CREEP UP TO THE MID 30S TO POSSIBLY LOWER 40S IN THE
FORECAST AREA...WHICH COMBINED WITH ANY RAIN/DRIZZLE WOULD LEAD TO
QUICK SNOW MELT AND POSSIBLY ADVECTION FOG.
BEYOND...BOTH THE 12.00 GFS AND EC HAVE THE NEXT COLD AIR DOME BUILT
IN SOUTHERN CANADA BY MIDWEEK WITH 850 MB TEMPS OF -30C OR COLDER.
THEY BOTH DIFFER VASTLY FROM RUN TO RUN IN HOW FAR SOUTH AND EAST
AND HOW QUICKLY THIS EVOLVES...AND WHETHER OR NOT IT WILL EVEN GET
HERE. THE JET LOOKS TO REMAIN ACTIVE AS WELL...SO CONFIDENCE IN THIS
PERIOD IS LOW.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WEST/NORTHWEST WINDS BECOMING MORE NORTHWEST AND SLOWLY
INCREASING THROUGH THE EARLY AFTERNOON WITH THE STRONGER GUSTS
NOT EXPECTED UNTIL LATE THIS AFTERNOON/EARLY EVENING.
* IFR CEILINGS THROUGH THE REMAINDER OF THE DAY/NIGHT.
* LIGHT TO MODERATE SNOW TO CONTINUE THIS AFTERNOON WITH SNOW
EXPECTED TO INCREASE LATER THIS AFTERNOON WITH PERIODS OF HEAVY
SNOW POSSIBLE. VIS OF 1/2SM EXPECTED WITH PERIODS OF 1/4SM.
* LIGHT SNOW TO SLOWLY DIMINISH TONIGHT INTO EARLY FRIDAY MORNING
WITH VIS SLOWLY IMPROVING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
LARGE AREA OF LIGHT TO MODERATE SNOW CONTINUES TO DEVELOP AND
SLOWLY MOVE ACROSS THE TERMINALS EARLY THIS AFTERNOON AS LARGE
SCALE FORCING MOVES THROUGH THE REGION. EXPECT THIS LIGHT TO
MODERATE SNOW TO PERSIST INTO THE AFTERNOON AND EVEN EXPECT AN
INCREASE IN INTENSITY WITH PERIODS OF HEAVY SNOW POSSIBLE. VIS
LOOKS TO HOLD AROUND 1/2SM WITH PERIODS OF 1/4SM POSSIBLE LATER
THIS AFTERNOON. THIS PERIOD OF HEAVIER SNOW IS EXPECTED TO
CONTINUE INTO THE EARLY AFTERNOON AND EARLY EVENING WITH SNOWFALL
RATES ALSO BECOMING AN ISSUE. LATER THIS EVENING...LIGHT TO
MODERATE SNOW CAN STILL BE EXPECTED WITH SOME UNCERTAINTY AS TO IF
ANOTHER PERIOD OF HEAVIER SNOW COULD BE OBSERVED. WILL CONTINUE TO
MONITOR LATEST TRENDS AND ADJUST ACCORDINGLY FOR THE EARLY EVENING
TIME FRAME. THEN EXPECT THE HEAVIEST SNOW TO START SHIFTING EAST
LATE IN THE EVENING. CEILINGS ARE LOCKED IN AT IFR AND WILL REMAIN
FOR THE REMAINDER OF TODAY AND TONIGHT...BEFORE A SLOW UPWARD
TRENDS TO MVFR BY MID TO LATE MORNING ON FRIDAY AS THIS SYSTEM
SLOWLY TRANSITIONS TO THE EAST.
WEST/NORTHWEST WINDS HAVE BEEN SLOW TO INCREASE TODAY BUT STILL
EXPECT THEM TO INCREASE LATER THIS AFTERNOON AND EVENING.
WINDS/GUSTS WILL INCREASE TO AROUND THE 25KT RANGE DURING THAT
TIME WITH A MORE NORTHWEST WIND EXPECTED AS SURFACE TROUGH PUSHES
THROUGH. WEST/NORTHWEST WINDS WILL THEN SLOWLY DIMINISH FRIDAY
MORNING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.
* HIGH CONFIDENCE WITH CEILINGS AND TRENDS TODAY/TONIGHT.
* MEDIUM HIGH CONFIDENCE WITH SNOW/VIS TRENDS TODAY...WITH MEDIUM
CONFIDENCE OF SNOW/VIS TRENDS TONIGHT INTO EARLY FRIDAY MORNING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...CHANCE OF SNOW WITH MVFR OR IFR CIGS/VIS DEVELOPING BY
THE AFTERNOON AND CONTINUING INTO THE NIGHT.
SUNDAY...VFR. WX NIL.
MONDAY...IFR CIGS/VIS IN DRIZZLE OR LIGHT RAIN.
TUESDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS.
WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
309 AM CST
A LOW PRESSURE SYSTEM OVER OHIO WILL MOVE INTO MICHIGAN THIS
AFTERNOON AND STRENGTHEN. IN ADDITION...ARCTIC AIR WILL POUR INTO
THE REGION TODAY. BETWEEN THESE TWO COMPONENTS...LOW END GALES WILL
FORM ACROSS LAKE MICHIGAN TODAY. WINDS WILL BE NORTH TO NORTHWEST
ALONG THE LAKE...THEREFORE EXPECTING GALES TO LEAK INTO THE INDIANA
NEARSHORE ZONES AS WELL. UPGRADED THE GALE WATCH TO A GALE WARNING
WITH THIS ISSUANCE. THE LOW QUICKLY MOVES EASTWARD FRIDAY AND HIGH
PRESSURE MOVES IN BEHIND IT FRIDAY NIGHT INTO SATURDAY. WINDS WILL
BECOME WESTERLY AND DIMINISH QUICKLY BEHIND THE LOW...BUT EXPECTING
HIGH WAVES TO PERSIST THROUGH EARLY FRIDAY NIGHT IN THE NEARSHORE
ZONES. A WEAKENING LOW PRESSURE SYSTEM PASSES SOUTH OF THE LAKE
LATE SATURDAY...AND WILL HAVE LITTLE TO NO IMPACT ON THE LAKE.
WINDS REMAIN WEAK THROUGH THE WEEKEND BUT BEGIN TO TURN SOUTHERLY
AND INCREASE SUNDAY EVENING AS THE PRESSURE GRADIENT INCREASES
BETWEEN HIGH PRESSURE OVER THE ATLANTIC COAST AND A DEVELOPING LOW
PRESSURE SYSTEM OVER MANITOBA.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-
ILZ022 UNTIL 9 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-
ILZ019-ILZ021-ILZ032 UNTIL 4 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 AM FRIDAY.
IN...WINTER STORM WARNING...INZ001-INZ002 UNTIL 9 AM FRIDAY.
WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 AM FRIDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL
MIDNIGHT SATURDAY.
GALE WARNING...LMZ744-LMZ745...9 PM THURSDAY TO 3 PM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 PM THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
206 AM CST THU JAN 12 2012
.DISCUSSION...
840 PM CST
AN INITIAL ANALYSIS HAS BEEN MADE OF 00Z UPPER AIR DATA AS WELL AS
THE 12.00 NAM AND 11.21 SREF. HAVE MADE MODIFICATIONS TO THE START
TIME OF THE SNOWFALL WHERE CONFIDENCE HAS INCREASED...BUT THE
WINTER WEATHER ADVISORY START TIMES STILL LOOK VALID.
RIGHT NOW THE AREA IS NICELY LOCATED UNDER A WEDGE OF SUPPRESSION
AND DRY AIR BETWEEN THE LOW OVER THE OHIO RIVER VALLEY AND THE
INCOMING DIGGING TROUGH AND ARCTIC FRONT. THIS SHOULD HOLD FOR A
WHILE AND LATEST GUIDANCE HAS CAUGHT ONTO THIS WITH SLOWER
PROGRESSION OF THE POST-FRONTAL FORCING AND SNOW ACROSS IA AND
INTO WESTERN MO. THE SURFACE COLD FRONT WILL CONTINUE
EAST...TURNING WINDS NORTHWEST AND BRINGING THE TEMPERATURES DOWN.
ALREADY THE CLEARING HAS ALLOWED FOR COOLING...AND THERE IS ALMOST
NO DOUBT THAT PRECIPITATION TYPE ONSET WILL BE SNOW GIVEN THE
COOLING COLUMN. THE NAM/RUC FORCING AND HRRR REFLECTIVITY HAVE
FORCING FOR PRECIPITATION STILL WEST OF INTERSTATE 39 BY 12Z...AND
STILL WEST OF CHICAGOLAND BY 15Z. THE SREF ENSEMBLE MEMBERS ALSO
HAVE A TIGHTER PACKING THROUGH 15Z FOR INCREASED CONFIDENCE...AND
THIS PACKING IS ON A SLOWER SOLUTION. HAVE ADDED HIGHER TEMPORAL
RESOLUTION POPS TO BETTER DEFINE THE ONSET TIME.
A NICE -37C 500MB COLD POCKET ASSOCIATED WITH THE WESTERN TROUGH
WILL DIG SOUTHEAST INTO THE LATE MORNING AND THE PHASING OF THE
SYSTEMS WILL RAPIDLY BEGIN. LARGE SCALE OMEGA INCREASES ACROSS THE
AREA WITH SATURATION WORKING ITS WAY ACROSS CHICAGOLAND AND
NORTHWEST IN. SO ONSET IN CHICAGOLAND STILL LOOKS TO BE PRIOR TO
NOON...AND LIKELY BETWEEN 9 AM AND NOON FOR MUCH OF THE AREA. THE
AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE FORECAST AREA
CONTINUES TO BE THE PERIOD MOST FAVORED FOR HEAVIER SNOW. THIS IS
BECAUSE OF 1. STRONGER UPPER LEVEL SUPPORT 2. THE TIGHTEST MID-
LEVEL THERMAL GRADIENT SUPPORTING TEMPORARY BURSTS OF
MODERATE/HEAVY ACTIVITY WITHIN BANDS 3. SNOW-TO-WATER EFFICIENCIES
INCREASING WITH A COOLING COLUMN AND DEEPER DENDRITIC
GROWTH...ESPECIALLY AFTER 3 PM...AND 4. LAKE ENHANCED SUPPORT INTO
NORTHWEST INDIANA /WHICH ACTUALLY CONTINUES INTO THE NIGHTTIME
HOURS. THIS IS THE AREA THAT WILL BE PARTICULARLY WATCHED FOR
POSSIBLE UPGRADE TO A WARNING IN TIME.
THE ONLY CHANGE WITH THE THURSDAY AFTERNOON PORTION OF THE
FORECAST WAS TO SLIGHTLY INCREASE SNOWFALL AMOUNTS SOUTH OF
INTERSTATE 80. AMOUNTS ON THURSDAY AFTERNOON ACROSS THE AREA COULD
BE PRETTY HOMOGENEOUS...WITH TEMPORARY BURSTS/BANDS SUPPORTING
LOCALIZED HIGHER AREAS. THE SLOWER ONSET TIME MAY MEAN LESS
SNOWFALL IN THE MORNING ACROSS THE SOUTH THOUGH...SO OVERALL
FORECAST AMOUNTS CAME OUT FAIRLY CLOSE...WITH NO CHANGES FOR
CHICAGOLAND ON TOTALS.
MTF
//PREV DISCUSSION...
243 PM CST
WINTER STORM...TONIGHT THROUGH FRIDAY NIGHT...
HAVE ISSUED WINTER WEATHER ADVISORIES FOR SNOW AND BLOWING SNOW
WHICH WILL COVER THE CAW FOR THURSDAY INTO EARLY FRIDAY.
STRONG SHORT WAVE TROUGH DIGGING SOUTHEAST ACROSS THE NORTHERN
PLAINS WILL CONTINUE TO CARVE OUT A DEEP UPPER TROUGH ACROSS THE
CENTRAL CONUS TONIGHT/THURSDAY...WITH A CLOSED UPPER LOW
DEVELOPING ACROSS THE MID-MISSISSIPPI VALLEY. PRE-EXISTING SURFACE
LOW PRESSURE OVER THE OHIO VALLEY WILL DEEPEN AND LIFT NORTH INTO
THE GREAT LAKES REGION IN RESPONSE TO DEVELOPING UPPER LOW...AND
STRONG LOW LEVEL BAROCLINICITY WITH INTRUSION OF LOW LEVEL ARCTIC
AIR. UPPER DIVERGENCE IN LEFT EXIT REGION OF CYCLONICALLY CURVED
UPPER JET STREAK WILL ALSO AID IN DEVELOPING DEEP SYNOPTIC SCALE
ASCENT ACROSS THE THE AREA. 12Z MODEL GUIDANCE IS GENERALLY IN
VERY GOOD AGREEMENT IN DEPICTION OF EVOLUTION OF SYSTEM OVER THE
NEXT 36 HOURS...SAVE FOR SOME QPF DIFFERENCES...WITH THE WRF-NAM
BEING MORE GENEROUS WITH THE PRECIP/SNOW AMOUNTS. GUIDANCE DOES
INDICATE THAT THE GREATEST AMOUNTS WILL LIKELY BE ACROSS NORTHEAST
IL/NORTHWEST INDIANA WHERE SOME LAKE-ENHANCEMENT POTENTIAL
EXISTS...AND WHERE LARGER SCALE DEFORMATION AXIS EVENTUALLY SETS
UP AS SYSTEM DEEPENS AND MOVES OFF TO THE EAST-NORTHEAST LATER
THURSDAY AND THURSDAY NIGHT. WHILE FORCING DECREASES QUICKLY LATE
THURSDAY NIGHT...LIGHTER SNOW/SNOW SHOWERS IS/ARE EXPECTED TO
CONTINUE INTO FRIDAY MORNING. THE PERIOD MOST FAVORABLE FOR MORE
SIGNIFICANT ACCUMULATION WILL SLIDE FROM WEST TO EAST ACROSS THE
AREA FROM MID THURSDAY MORNING THROUGH VERY EARLY FRIDAY EVENING.
SNOWFALL AMOUNTS ARE TRICKY WITH THIS SYSTEM...LARGELY DUE TO DEGREE
OF COOLING OF THE COLUMN AS DEPTH OF ARCTIC AIR INCREASES LATE
THURSDAY AND THURSDAY NIGHT...AS WELL AS DUE TO AFOREMENTIONED
POTENTIAL FOR LAKE-ENHANCEMENT IN COUNTIES BORDERING LAKE MICHIGAN.
MODEL SNOW/LIQUID RATIOS RANGE FROM 10:1 AT ONSET...TO 15 OR 20:1
LATER IN THE EVENT. HAVE GENERALLY USED HPC QPF...WITH A LITTLE
BLENDING OF WRF OUTPUT...AND RATIOS RANGING FROM 10:1 TO 17:1
THROUGH THE EVENT FOR SNOWFALL FORECAST. THIS YIELDS ROUGHLY 3-5
INCHES ACROSS SOUTHWESTERN CWA...TO 4-6 INCHES FOR NORTHEAST CWA
COUNTIES NOT ALONG THE LAKE...TO 4-8 INCHES FOR THE LAKE ADJOINING
COUNTIES. ACCUMULATING SNOWFALL IS EXPECTED TO BE OVER NEARLY A 24
HOUR PERIOD...THOUGH EXPECT IT WILL FALL JUST SHORT OF THE 6
INCHES IN 12 HOURS OR 8 INCHES IN 24 HOURS CRITERIA FOR WINTER
STORM WARNING. BASED ON THIS...AND COLLABORATION WITH MKX/ILX AND
IWX HAVE ELECTED TO ISSUE A WINTER WEATHER ADVISORY FOR SNOW AND
BLOWING SNOW. NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 20-25
MPH THURSDAY AFTERNOON...AND MAY GUST 30-35 MPH THURSDAY NIGHT AS
LOW DEEPENS OFF TO OUR EAST. THIS WILL LIKELY RESULT IN
SIGNIFICANT BLOWING AND DRIFTING SNOW PARTICULARLY IN OPEN/RURAL
AREAS. IN ADDITION TO THE BLOWING/DRIFTING ISSUES...THESE WINDS
WILL COMBINE WITH ARCTIC AIR TO PRODUCE WIND CHILLS IN THE ZERO TO
-10 F RANGE THURSDAY NIGHT/EARLY FRIDAY MORNING.
THE POTENTIAL FOR LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO
NORTHWEST INDIANA ON FRIDAY...THOUGH FORECAST SOUNDINGS DEPICT WINDS
GRADUALLY BACKING MORE WEST-NORTHWEST WHICH SHOULD FORCE STRONGER
LAKE EFFECT BANDS INTO WFOS GRR/IWX AREAS.
RATZER
LONGER TERM...FRIDAY THROUGH EARLY NEXT WEEK...
THE CLOSED CIRCULATION ALOFT THAT WILL BRING THE BLAST OF WINTER
WEATHER WILL MOVE ACROSS THE NORTHEASTERN STATES BY THE AFTERNOON ON
FRIDAY. IN THE WAKE OF THIS SYSTEM WILL BE WEAK SURFACE RIDGING THAT
WILL FLIP WINDS BACK TO THE SOUTHWEST AND ADVECT IN A LITTLE WARMER
AIR FROM THE COLDER AIRMASS THAT WAS DUMPED ACROSS THE REGION. WHILE
STILL CHILLY...HIGHS WILL MANAGE TO GET WITHIN REACH OF NORMAL FOR
THIS TIME OF YEAR ON SATURDAY...WITH GENERALLY LOWER 30S EXPECTED
SOUTH OF I-80 AND TEMPS JUST BELOW NORMAL TO THE NORTH. INTO THE
EVENING ANOTHER CLIPPER WILL DIVE OUT OF THE NORTHERN PLAINS AND
ACROSS THE CWA THROUGH EARLY SUNDAY MORNING. THERE IS STILL A
LITTLE UNCERTAINTY WITH RESPECT TO THE TRACK OF THE CLIPPER MOVING
THROUGH...AS ALL GUIDANCE /ECMWF - GEMNH - GFS/ HAVE TRENDED A
LITTLE FURTHER SOUTH OVER THE LAST FEW RUNS...SO CONFIDENCE IS NOT
THE HIGHEST WITH THE LIKELIHOOD ON WHERE THE LOW WILL TRACK.
REGARDLESS...THE SYSTEM WILL MOVE THROUGH PRETTY QUICKLY AND ONLY
IMPACT THE CWA IN THE AFTERNOON TO EVENING HOURS WITH A LIGHT
DUSTING OF SNOW. DUE TO THE UNCERTAINTY...WILL MAINTAIN ONLY THE
MENTION OF CHANCE POPS AT THIS TIME BUT LEAN TOWARDS A LATER POINT
IN THE DAY FOR IT TO MOVE THROUGH. CONDITIONS WILL REMAIN NEAR TO
BELOW NORMAL TO CLOSE OUT THE WEEKEND.
RIDGING WILL THEN BUILD IN ON SUNDAY NIGHT AND INTO THE OPENING OF
NEXT WEEK ALLOWING TEMPERATURES TO CREEP UP TO ABOVE FREEZING
BUT...THERE IS SOME QUESTION AS TO HOW WARM IT WILL GET WITH SNOW
REMAINING ON THE GROUND THROUGH THAT TIME. NEXT UPPER LEVEL TROUGH
WILL SWING THROUGH MONDAY NIGHT INTO TUESDAY...LIFTING A SURFACE
FEATURE NORTHEAST THROUGH MICHIGAN INTO THAT TIME. PROFILES
SUGGEST THAT WITH THE MODERATE WARM AIR ADVECTION GOING ON...THAT
PTYPE WILL START AS RAIN BEFORE QUICKLY BECOMING SNOW AS THE
ENTIRE PROFILE DIPS BELOW FREEZING. THE ROLLER COASTER OF TEMPS
RISING AND FALLING WITH WEAK UPPER LEVEL DISTURBANCES ZIPPING
THROUGH ARE EXPECTED TO CONTINUE INTO NEXT WEEKEND.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* CEILINGS LOWING TO MVFR BY ARND 10Z...LOWERING TO IFR SHORTLY
AFTER THE SNOW ONSET.
* SNOW DEVELOPING BY ARND 16Z AND CONTINUING THROUGH THE
REMAINDER OF THE FORECAST PERIOD.
* VIS DROPPING TO IFR LIKELY SHORTLY AFTER SNOW ONSET. PERIODS OF
1/2SM VIS LIKELY FROM LATE AFTERNOON THROUGH THE EVENING WITH
INCREASING SNOWFALL RATES AND INCREASING WINDS.
* CHANCE OF VIS DROPPING TO 1/4SM OR LESS DURING THE EARLY EVENING
AS BLOWING SNOW DEVELOPS AS DECREASING TEMPERATURES CAUSE A
DRIER SNOW CHARACTERISTIC.
KREIN
//DISCUSSION...UPDATED 06Z...
NOT MUCH CHANGE FROM PREVIOUS THINKING.
THE FIRST APPRECIABLE WINTER WEATHER EVENT OF THE SEASON IS STILL
SET TO IMPACT THE TERMINALS FOR MUCH OF THE DAY ON THURSDAY AND INTO
THURSDAY NIGHT. THIS IS A RATHER COMPLEX AND DYNAMICAL STORM
SYSTEM THAT LOOKS TO BRING A PERIOD OF MODERATE TO HEAVY SNOW TO
THE NORTHEASTERN ILLINOIS TERMINALS DURING THE AFTERNOON AND
EVENING HOURS ON THURSDAY. THIS WILL BE THE MAIN CONCERN AS SNOW
AND BLOWING SNOW WILL LIKELY LEAD TO A PERIOD OF IFR TO LIFR VIS
AND CIGS THURSDAY AFTERNOON AND INTO THE EVENING.
THE MAIN COLD FRONT IS NOW MOVING ACROSS NORTH CENTRAL IL
NEAR KRFD. THIS FRONT SHOULD MOVE ACROSS NORTHEASTERN
ILLINOIS AFTER 07 UTC TONIGHT. BEHIND THIS FRONT...EXPECT WINDS TO
BECOME GUSTY OUT OF THE NORTHWEST. THE MAIN SURFACE LOW MOVING NORTH
ACROSS THE OHIO VALLEY LATE THIS EVENING...WILL QUICKLY INTENSIFY
DURING THE MORNING ON THURSDAY ACROSS THE GREAT LAKES REGION. THIS
WILL SET THE STAGE FOR GUSTY NORTHWEST WINDS THROUGH THE REMAINDER
OF THE FORECAST PERIOD.
AS FAR AS SNOWFALL...IT APPEARS SNOWFALL WILL BEGIN DURING
THE MID TO LATE MORNING HOURS (AFTER 16 UTC AT THE NORTHEASTERN
ILLINOIS TERMINALS) AS STRONG FORCING FOR ASCENT COMMENCES IN
RESPONSE TO THE ATMOSPHERIC DYNAMICS OF THIS DEEPENING SURFACE
LOW. I EXPECT THE ONSET TIME TO OCCUR AROUND OR SHORTLY AFTER 12
UTC AT KRFD. THE SNOW SHOULD PICK UP IN INTENSITY DURING THE
AFTERNOON HOURS (AFTER 19 UTC) AS THE DYNAMICS REACH A PEAK ALONG
THE LEADING EDGE OF THE COLDEST AIR. THIS STILL APPEARS TO
POSSIBLY RESULT IN A PERIOD OF VISIBILITIES IN SNOW AND BLOWING
SNOW UNDER 1/2 MILE THROUGH THE AFTERNOON AND EARLY EVENING. THE
SNOWFALL SHOULD BEGIN TO ABATE LATER THURSDAY NIGHT INTO FRIDAY
MORNING AS THE STORM SYSTEM SHIFTS EAST ACROSS THE EASTERN GREAT
LAKES.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE WITH CEILING AND WIND TRENDS.
* HIGH CONFIDENCE OF SNOW WITH MEDIUM CONFIDENCE OF TIMING AND VIS
TRENDS ON THURSDAY.
* LOWER CONFIDENCE IN THE PROBABILITY OF VISIBILITY OCCASIONALLY
DROPPING TO 1/4SM OR LESS
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...IFR CIGS/VIS EARLY IN SNOW AND BLOWING SNOW. CONDITIONS
IMPROVING THROUGH THE DAY.
SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS.
SUNDAY...VFR.
MONDAY AND TUESDAY...CHANCE OF SNOW SHOWERS WITH MVFR CIGS/VIS.
KJB
&&
.MARINE...
145 PM CST
LOW PRESSURE OVER THE TENNESSEE VALLEY THIS AFTERNOON WILL CURVE
NORTHEAST INTO THE EASTERN GREAT LAKES AND INTENSIFY LATE TONIGHT
AND THURSDAY AS AN ARCTIC AIR MASS PLUNGES SOUTH FROM CENTRAL
CANADA AND THE NORTHERN PLAINS. LIGHT SOUTHEAST WINDS THIS
AFTERNOON WILL BACK NORTHEAST...THEN NORTHWEST AND INCREASE LATE
TONIGHT AND THURSDAY MORNING. WINDS WILL CONTINUE TO RAMP UP
THURSDAY WITH GALE FORCE WINDS OVER THE OPEN WATERS BY LATE
AFTERNOON. WITH WINDS OFFSHORE...WILL LIKELY STAY BELOW GALES FOR
THE ILLINOIS NEARSHORE...BUT EXPECT GALE FORCE WINDS ALONG THE
INDIANA NEARSHORE WATERS. GALES WILL LIKELY CONTINUE THROUGH
FRIDAY AFTERNOON AS THE LOW SPINS OVER THE LOWER LAKES FOR A WHILE
BEFORE MOVING EAST. HIGH PRESSURE WILL BRING DIMINISHING WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. WEAK LOW PRESSURE MOVING
THROUGH THE MIDWEST SATURDAY AFTERNOON AND EVENING WILL HAVE
LITTLE IMPACT ON THE LAKE. AS HIGH PRESSURE MOVES EAST ACROSS THE
LAKES SUNDAY WINDS WILL VEER SOUTH THEN INCREASE SUNDAY NIGHT AND
MONDAY.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-
ILZ019-ILZ021-ILZ032...6 AM THURSDAY TO 4 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-
ILZ020-ILZ022-ILZ023-ILZ033-ILZ039...9 AM THURSDAY TO 9 AM
FRIDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9
AM THURSDAY TO 9 AM FRIDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM
THURSDAY TO 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...NOON
THURSDAY TO MIDNIGHT SATURDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...NOON THURSDAY TO 3 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1116 PM CST WED JAN 11 2012
.DISCUSSION...
ISSUED 845 PM CST WED JAN 11 2012
QUICK GLANCE AT THE 00Z NAM...AS WELL AS THE HRRR AND RUC MODELS...
INDICATES NO BIG CHANGES NEEDED TO HEADLINES OR SNOW SCENARIO
FORECAST. COLD FRONT NOW APPROACHING THE IL RIVER WITH GUSTY
NORTHWEST WINDS AND LOW CLOUDS. RADARS INDICATE THE SNOW IS LAGGING
BACK OVER CENTRAL IA...SO NO POPS THIS EVENING STILL LOOK ON TRACK.
THE NAM AND HRRR MODELS INDICATE THE LEADING EDGE OF THE SNOW
REACHING THE MIDDLE OF THE FORECAST AREA BY 12Z. WATER VAPOR LOOPS
SHOWING THE DEEPENING/AMPLIFYING TROUGH OVER THE PLAINS...WITH
INCREASING INFLECTION OVER NEB BEING THE BEGINNINGS OF THE LOW
CLOSING OFF. THE EXPANDING DARK AREA ON SATELLITE ALONG THE TROF
AXIS AND DOWN INTO THE INFLECTION OVER SOUTHERN NEB AND NORTHWESTERN
KS SUGGESTS THAT STRATOSPHERIC POTENTIAL VORTICITY IS POKING
DOWNWARD ON THE WESTERN FLANK OF THE TROUGH...WHICH WILL ACT TO
ACCELERATE THE DEEPENING PROCESS.
MOST OF THE SYNOPTIC MODEL OUTPUT AGREES ON TRACKING THE CENTER OF
THE DEEPENING UPPER LOW ACROSS THE SOUTHERN THIRD OF IL FROM LATE
MORNING TO LATE AFTERNOON THURSDAY. DURING THAT TIME...PV AND
DIFLUENCE WILL BE ROTATING THROUGH THE EASTERN QUADRANT AND INTO THE
NORTHEASTERN QUADRANT OF THE LOW...WHICH WILL EXTEND EAST/WEST
THROUGH CENTRAL IL. IN ADDITION...ISENTROPIC ANALYSES INDICATE A
DECENT UPGLIDE ON THE 300K-290K SURFACES IN THE SAME GENERAL
AREA...WITH SPECIFIC HUMIDITIES OF 1.5-2.5 G/KG. SO SNOW AMOUNTS OF
3-5 INCHES OVER THE NORTHERN HALF OF THE AREA STILL LOOK GOOD...WITH
POSSIBLE MESOSCALE ENHANCEMENT OF SNOW BANDS.
WILL FRESHEN UP THE WINTER WEATHER ADVISORY PRODUCT SHORTLY.
04
&&
.AVIATION...
ISSUED 1116 PM CST WED JAN 11 2012
UPPER LOW CONTINUES TO DEEPEN AS IT MOVES SOUTHEASTWARD ACROSS NEB.
THE LOW WILL MOVE THROUGH MO THEN ACROSS IL TO THE SOUTH OF THE TAF
SITES ON THURSDAY. COLD FRONT AHEAD OF THIS LOW HAS ALREADY MADE IT
THROUGH ALMOST ALL TERMINALS...AND IT IS NOT FAR FROM CMI. 15-25 KT
NORTHWESTERLY WINDS WILL INCREASE ON THURSDAY WITH GUSTS 30-35 KT.
MVFR 1K-2K FT STRATOCU IS CURRENTLY AN HOUR OR SO BEHIND THE
FRONT...BUT THE SNOW IS STILL LAGGING BACK IN EASTERN IA AND CENTRAL
MO. AT THE CURRENT RATE OF MOVEMENT...THE SNOW SHOULD BE MOVING INTO
THE PIA/SPI AREAS AROUND 12Z OR SHORTLY THEREAFTER. IFR CONDITIONS
OR LOWER IN SNOW/BLOWING SNOW WILL BE COMMON MUCH OF THURSDAY. SNOW
RATES WILL BE DECREASING SOMEWHAT AFTER 00Z FRI AS THE SYSTEM MOVES
OFF...BUT LOW CIGS AND LIGHT SNOW/BLOWING SNOW WILL CONTINUE THROUGH
AT LEAST 06Z.
04
&&
.PREV DISCUSSION...
ISSUED 220 PM CST WED JAN 11 2012
SNOW...WIND AND MUCH COLDER WEATHER HEADING FOR CENTRAL...EAST
CENTRAL AND SOUTHEAST ILLINOIS THURSDAY INTO FRIDAY.
SOUTHERN STREAM SHORTWAVE AND ASSOCIATED SURFACE LOW SOUTH OF THE
OHIO RIVER SPREAD RAIN AS FAR NORTH AS SPRINGFIELD EAST NORTHEAST TO
CHAMPAIGN. FURTHER NORTH AND WEST...SUNSHINE HAS BROUGHT EARLY
AFTERNOON TEMPERATURES INTO THE MID AND UPPER 50S. THE COLD FRONT
WHICH WILL BRING A DRASTIC CHANGE IN OUR WEATHER AS PUSHING THRU
CENTRAL IOWA EARLY THIS AFTERNOON WITH TEMPERATURES STRUGGLING THRU
THE SINGLE DIGITS AND LOW TEENS OVER THE DAKOTAS.
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
SNOW AMOUNTS...FALLING TEMPERATURES AND GUSTY WINDS THE MAIN FORECAST
CONCERN THROUGH LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING.
CONDITIONS ARE EXPECTED TO DETERIORATE RAPIDLY TOMORROW MORNING
WEST...AND OVER THE EAST BY EARLY AFTERNOON.
MODELS IN DECENT AGREEMENT WITH THE MOVEMENT OF THE SOUTHERN STREAM
UPPER LEVEL WAVE AS IT GETS ABSORBED BY THE STRONGER NORTHERN STREAM
ENERGY LATER TOMORROW WHICH IN EFFECT WILL PRODUCE A DEEPENING
SURFACE WAVE WHICH IS FORECAST TO TRACK NORTH INTO EASTERN LOWER
MICHIGAN BY 00Z FRIDAY. SNOW SHOULD TRACK INTO FAR WESTERN IL
BETWEEN 09Z AND 12Z AFFECTING THE MORNING COMMUTE MAINLY IN AREAS
WEST OF INTERSTATE 55 WITH LOCATIONS TO THE EAST SEEING THE SNOW
DEVELOP BY MID TO LATE MORNING. THE COMMUTE HOME TOMORROW EVENING
LOOKS TO BE A REAL MESS. NAM-WRF TIME HEIGHT CROSS SECTIONS SHOWING
THE BEST DEEP LAYERED MOISTURE AND OMEGA COINCIDENT WITH THE SNOW
GROWTH REGION TO BE OCCURRING FROM MID MORNING TO LATE AFTERNOON
WEST AND LATE MORNING INTO THE EVENING HOURS EAST. TEMPERATURES THRU
THE DAY WILL BE STEADY OR SLOWLY FALLING WITH FRIDAY MORNING LOWS IN
THE 10 TO 15 DEGREE RANGE.
LOOKING AT BOTH THE NAM AND GFS ISENTROPIC PROFILES AT 290K...SUGGEST
THE BEST ASCENT AND LOWEST PRESSURE DEFICITS OCCUR IN THE 00Z TO 06Z
TIME FRAME WITH THE BETTER LIFT SHIFTING OFF TO OUR EAST LATE
THURSDAY NIGHT/FRIDAY MORNING. MODELS SUGGEST SOME DECENT 850-500 MB
FRONTOGENETICAL FORCING COUPLED WITH WEAK STATIC STABILITY
INDICATING THE POTENTIAL FOR SOME BANDED SNOWFALL...ESPECIALLY
ACROSS OUR NORTH LATER TOMORROW MORNING INTO THE AFTERNOON HOURS.
SNOW RATIOS START OUT AT 13:1 BUT FORECAST SOUNDINGS SUGGEST 16:1 OR
EVEN GREATER TOWARDS LATE THU AFTN AND EVENING. HIGHEST SNOW AMOUNTS
CONTINUE TO BE ALONG AND NORTH OF I-74 WHERE 3 TO 5 INCHES WILL
OCCUR...WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE...ESPECIALLY IN
OUR FAR NORTHEASTERN AREAS. FURTHER SOUTH...TOTAL SNOW AMOUNTS LOOK
TO BE IN THE ORDER OF 1 TO 3 INCHES WITH AN INCH OR TWO ALONG AND
SOUTH OF I-70. ISSUED THE WINTER WEATHER ADVISORY EARLIER AND WILL
CONTINUE WITH IT ACROSS THE ENTIRE FORECAST AREA INTO FRIDAY
MORNING. AS THE SURFACE SYSTEM DEEPENS LATER TONIGHT INTO THUR...NW
WINDS WILL INCREASE TO BETWEEN 20 TO 25 MPH...WITH OCCASIONAL GUSTS
APPROACHING 35 MPH...PRODUCING QUITE A BIT OF BLOWING SNOW. WINDS
SHOULD GRADUALLY DECREASE FRIDAY MORNING AS THE LOW PULLS WELL OFF
TO OUR EAST. WIND CHILLS DROP INTO THE SINGLE DIGITS NORTHWEST BY
TOMORROW AFTN...AND DOWN TO BETWEEN -3 TO -8 FRIDAY MORNING.
TRANQUIL WEATHER WILL RETURN FRIDAY AFTN INTO FRIDAY NIGHT WITH SOME
RATHER NIPPY TEMPERATURES IN STORE FOR THE AREA...ESPECIALLY WITH A
FRESH SNOW PACK IN PLACE. WENT BELOW MOST GUID VALUES FRI NIGHT/SAT
MORNING WITH OUR NORTH SEEING SINGLE DIGITS FOR LOWS. HOWEVER...IF
OUR NEXT WEATHER SYSTEM TRACKING IN FROM THE NORTHWEST ON SATURDAY
IS QUICKER THAN WHAT MODELS INDICATE...CLOUDS MAY GET INTO THE AREA
FASTER WHICH WOULD HELP KEEP THE TEMPS UP. FOR NOW... WL GO WITH THE
COLDER LOWS EARLY SATURDAY MORNING. CLIPPER SYSTEM TRACKING QUICKLY
SOUTHEAST INTO THE AREA ON SATURDAY BRINGING A THREAT OF LIGHT SNOW
TO THE AREA...ESPECIALLY ACRS THE NORTHEAST HALF OF THE FORECAST
AREA. GFS AND ECMWF IS FURTHEST SOUTH WHICH WOULD BRING SOME LIGHT
ACCUMULATING SNOWS TO OUR NORTH...WHILE THE NAM WAS A BIT FURTHER
NORTH AND NOT NEARLY AS AGGRESSIVE WITH THE QPF. FOR NOW...WILL KEEP
LOW CHANCE POPS GOING ACRS THE NORTH AND EAST.
LONG TERM...SUNDAY THROUGH WEDNESDAY
UPPER LEVEL HEIGHTS REBOUND OVER THE MIDWEST SUNDAY INTO MONDAY
WHICH WILL SPELL WARMER WEATHER RETURNING TO THE AREA. DESPITE THE
SNOW COVER...WE SHOULD SEE AFTERNOON TEMPS PUSH BACK INTO THE UPPER
20S TO MIDDLE 30S ON SUNDAY...AND UPPER 30S TO MIDDLE 40S BY MONDAY
WITH INCREASING SOUTHERLY WINDS. OUR NEXT WEATHER SYSTEM LOOKS TO
AFFECT THE AREA LATE MONDAY INTO MONDAY NIGHT WITH TEMP PROFILES
WARM ENOUGH TO SUPPORT MOSTLY RAIN WITH POSSIBLY A CHANGEOVER TO
LIGHT SNOW OR FLURRIES AS THE SYSTEM PULLS AWAY AND COLDER AIR IS
DRAWN SOUTHEAST INTO OUR AREA ON TUES. AFTER A BRIEF SHOT OF COLD
AIR MIDWEEK...A MORE ZONAL FLOW PATTERN WILL DEVELOP ACROSS THE
LOWER 48 RESULTING IN TEMPS AOA NORMAL FOR THE REMAINDER OF THE WEEK.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 9 AM THURSDAY TO 9 AM CST FRIDAY
FOR ILZ038-043>046-052>057-061>063-066>068-071>073.
WINTER WEATHER ADVISORY FROM 6 AM THURSDAY TO 6 AM CST FRIDAY
FOR ILZ027>031-036-037-040>042-047>051.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1046 PM CST WED JAN 11 2012
.DISCUSSION...
840 PM CST
AN INITIAL ANALYSIS HAS BEEN MADE OF 00Z UPPER AIR DATA AS WELL AS
THE 12.00 NAM AND 11.21 SREF. HAVE MADE MODIFICATIONS TO THE START
TIME OF THE SNOWFALL WHERE CONFIDENCE HAS INCREASED...BUT THE
WINTER WEATHER ADVISORY START TIMES STILL LOOK VALID.
RIGHT NOW THE AREA IS NICELY LOCATED UNDER A WEDGE OF SUPPRESSION
AND DRY AIR BETWEEN THE LOW OVER THE OHIO RIVER VALLEY AND THE
INCOMING DIGGING TROUGH AND ARCTIC FRONT. THIS SHOULD HOLD FOR A
WHILE AND LATEST GUIDANCE HAS CAUGHT ONTO THIS WITH SLOWER
PROGRESSION OF THE POST-FRONTAL FORCING AND SNOW ACROSS IA AND
INTO WESTERN MO. THE SURFACE COLD FRONT WILL CONTINUE
EAST...TURNING WINDS NORTHWEST AND BRINGING THE TEMPERATURES DOWN.
ALREADY THE CLEARING HAS ALLOWED FOR COOLING...AND THERE IS ALMOST
NO DOUBT THAT PRECIPITATION TYPE ONSET WILL BE SNOW GIVEN THE
COOLING COLUMN. THE NAM/RUC FORCING AND HRRR REFLECTIVITY HAVE
FORCING FOR PRECIPITATION STILL WEST OF INTERSTATE 39 BY 12Z...AND
STILL WEST OF CHICAGOLAND BY 15Z. THE SREF ENSEMBLE MEMBERS ALSO
HAVE A TIGHTER PACKING THROUGH 15Z FOR INCREASED CONFIDENCE...AND
THIS PACKING IS ON A SLOWER SOLUTION. HAVE ADDED HIGHER TEMPORAL
RESOLUTION POPS TO BETTER DEFINE THE ONSET TIME.
A NICE -37C 500MB COLD POCKET ASSOCIATED WITH THE WESTERN TROUGH
WILL DIG SOUTHEAST INTO THE LATE MORNING AND THE PHASING OF THE
SYSTEMS WILL RAPIDLY BEGIN. LARGE SCALE OMEGA INCREASES ACROSS THE
AREA WITH SATURATION WORKING ITS WAY ACROSS CHICAGOLAND AND
NORTHWEST IN. SO ONSET IN CHICAGOLAND STILL LOOKS TO BE PRIOR TO
NOON...AND LIKELY BETWEEN 9 AM AND NOON FOR MUCH OF THE AREA. THE
AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE FORECAST AREA
CONTINUES TO BE THE PERIOD MOST FAVORED FOR HEAVIER SNOW. THIS IS
BECAUSE OF 1. STRONGER UPPER LEVEL SUPPORT 2. THE TIGHTEST MID-
LEVEL THERMAL GRADIENT SUPPORTING TEMPORARY BURSTS OF
MODERATE/HEAVY ACTIVITY WITHIN BANDS 3. SNOW-TO-WATER EFFICIENCIES
INCREASING WITH A COOLING COLUMN AND DEEPER DENDRITIC
GROWTH...ESPECIALLY AFTER 3 PM...AND 4. LAKE ENHANCED SUPPORT INTO
NORTHWEST INDIANA /WHICH ACTUALLY CONTINUES INTO THE NIGHTTIME
HOURS. THIS IS THE AREA THAT WILL BE PARTICULARLY WATCHED FOR
POSSIBLE UPGRADE TO A WARNING IN TIME.
THE ONLY CHANGE WITH THE THURSDAY AFTERNOON PORTION OF THE
FORECAST WAS TO SLIGHTLY INCREASE SNOWFALL AMOUNTS SOUTH OF
INTERSTATE 80. AMOUNTS ON THURSDAY AFTERNOON ACROSS THE AREA COULD
BE PRETTY HOMOGENEOUS...WITH TEMPORARY BURSTS/BANDS SUPPORTING
LOCALIZED HIGHER AREAS. THE SLOWER ONSET TIME MAY MEAN LESS
SNOWFALL IN THE MORNING ACROSS THE SOUTH THOUGH...SO OVERALL
FORECAST AMOUNTS CAME OUT FAIRLY CLOSE...WITH NO CHANGES FOR
CHICAGOLAND ON TOTALS.
MTF
//PREV DISCUSSION...
243 PM CST
WINTER STORM...TONIGHT THROUGH FRIDAY NIGHT...
HAVE ISSUED WINTER WEATHER ADVISORIES FOR SNOW AND BLOWING SNOW
WHICH WILL COVER THE CAW FOR THURSDAY INTO EARLY FRIDAY.
STRONG SHORT WAVE TROUGH DIGGING SOUTHEAST ACROSS THE NORTHERN
PLAINS WILL CONTINUE TO CARVE OUT A DEEP UPPER TROUGH ACROSS THE
CENTRAL CONUS TONIGHT/THURSDAY...WITH A CLOSED UPPER LOW
DEVELOPING ACROSS THE MID-MISSISSIPPI VALLEY. PRE-EXISTING SURFACE
LOW PRESSURE OVER THE OHIO VALLEY WILL DEEPEN AND LIFT NORTH INTO
THE GREAT LAKES REGION IN RESPONSE TO DEVELOPING UPPER LOW...AND
STRONG LOW LEVEL BAROCLINICITY WITH INTRUSION OF LOW LEVEL ARCTIC
AIR. UPPER DIVERGENCE IN LEFT EXIT REGION OF CYCLONICALLY CURVED
UPPER JET STREAK WILL ALSO AID IN DEVELOPING DEEP SYNOPTIC SCALE
ASCENT ACROSS THE THE AREA. 12Z MODEL GUIDANCE IS GENERALLY IN
VERY GOOD AGREEMENT IN DEPICTION OF EVOLUTION OF SYSTEM OVER THE
NEXT 36 HOURS...SAVE FOR SOME QPF DIFFERENCES...WITH THE WRF-NAM
BEING MORE GENEROUS WITH THE PRECIP/SNOW AMOUNTS. GUIDANCE DOES
INDICATE THAT THE GREATEST AMOUNTS WILL LIKELY BE ACROSS NORTHEAST
IL/NORTHWEST INDIANA WHERE SOME LAKE-ENHANCEMENT POTENTIAL
EXISTS...AND WHERE LARGER SCALE DEFORMATION AXIS EVENTUALLY SETS
UP AS SYSTEM DEEPENS AND MOVES OFF TO THE EAST-NORTHEAST LATER
THURSDAY AND THURSDAY NIGHT. WHILE FORCING DECREASES QUICKLY LATE
THURSDAY NIGHT...LIGHTER SNOW/SNOW SHOWERS IS/ARE EXPECTED TO
CONTINUE INTO FRIDAY MORNING. THE PERIOD MOST FAVORABLE FOR MORE
SIGNIFICANT ACCUMULATION WILL SLIDE FROM WEST TO EAST ACROSS THE
AREA FROM MID THURSDAY MORNING THROUGH VERY EARLY FRIDAY EVENING.
SNOWFALL AMOUNTS ARE TRICKY WITH THIS SYSTEM...LARGELY DUE TO DEGREE
OF COOLING OF THE COLUMN AS DEPTH OF ARCTIC AIR INCREASES LATE
THURSDAY AND THURSDAY NIGHT...AS WELL AS DUE TO AFOREMENTIONED
POTENTIAL FOR LAKE-ENHANCEMENT IN COUNTIES BORDERING LAKE MICHIGAN.
MODEL SNOW/LIQUID RATIOS RANGE FROM 10:1 AT ONSET...TO 15 OR 20:1
LATER IN THE EVENT. HAVE GENERALLY USED HPC QPF...WITH A LITTLE
BLENDING OF WRF OUTPUT...AND RATIOS RANGING FROM 10:1 TO 17:1
THROUGH THE EVENT FOR SNOWFALL FORECAST. THIS YIELDS ROUGHLY 3-5
INCHES ACROSS SOUTHWESTERN CWA...TO 4-6 INCHES FOR NORTHEAST CWA
COUNTIES NOT ALONG THE LAKE...TO 4-8 INCHES FOR THE LAKE ADJOINING
COUNTIES. ACCUMULATING SNOWFALL IS EXPECTED TO BE OVER NEARLY A 24
HOUR PERIOD...THOUGH EXPECT IT WILL FALL JUST SHORT OF THE 6
INCHES IN 12 HOURS OR 8 INCHES IN 24 HOURS CRITERIA FOR WINTER
STORM WARNING. BASED ON THIS...AND COLLABORATION WITH MKX/ILX AND
IWX HAVE ELECTED TO ISSUE A WINTER WEATHER ADVISORY FOR SNOW AND
BLOWING SNOW. NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 20-25
MPH THURSDAY AFTERNOON...AND MAY GUST 30-35 MPH THURSDAY NIGHT AS
LOW DEEPENS OFF TO OUR EAST. THIS WILL LIKELY RESULT IN
SIGNIFICANT BLOWING AND DRIFTING SNOW PARTICULARLY IN OPEN/RURAL
AREAS. IN ADDITION TO THE BLOWING/DRIFTING ISSUES...THESE WINDS
WILL COMBINE WITH ARCTIC AIR TO PRODUCE WIND CHILLS IN THE ZERO TO
-10 F RANGE THURSDAY NIGHT/EARLY FRIDAY MORNING.
THE POTENTIAL FOR LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO
NORTHWEST INDIANA ON FRIDAY...THOUGH FORECAST SOUNDINGS DEPICT WINDS
GRADUALLY BACKING MORE WEST-NORTHWEST WHICH SHOULD FORCE STRONGER
LAKE EFFECT BANDS INTO WFOS GRR/IWX AREAS.
RATZER
LONGER TERM...FRIDAY THROUGH EARLY NEXT WEEK...
THE CLOSED CIRCULATION ALOFT THAT WILL BRING THE BLAST OF WINTER
WEATHER WILL MOVE ACROSS THE NORTHEASTERN STATES BY THE AFTERNOON ON
FRIDAY. IN THE WAKE OF THIS SYSTEM WILL BE WEAK SURFACE RIDGING THAT
WILL FLIP WINDS BACK TO THE SOUTHWEST AND ADVECT IN A LITTLE WARMER
AIR FROM THE COLDER AIRMASS THAT WAS DUMPED ACROSS THE REGION. WHILE
STILL CHILLY...HIGHS WILL MANAGE TO GET WITHIN REACH OF NORMAL FOR
THIS TIME OF YEAR ON SATURDAY...WITH GENERALLY LOWER 30S EXPECTED
SOUTH OF I-80 AND TEMPS JUST BELOW NORMAL TO THE NORTH. INTO THE
EVENING ANOTHER CLIPPER WILL DIVE OUT OF THE NORTHERN PLAINS AND
ACROSS THE CWA THROUGH EARLY SUNDAY MORNING. THERE IS STILL A
LITTLE UNCERTAINTY WITH RESPECT TO THE TRACK OF THE CLIPPER MOVING
THROUGH...AS ALL GUIDANCE /ECMWF - GEMNH - GFS/ HAVE TRENDED A
LITTLE FURTHER SOUTH OVER THE LAST FEW RUNS...SO CONFIDENCE IS NOT
THE HIGHEST WITH THE LIKELIHOOD ON WHERE THE LOW WILL TRACK.
REGARDLESS...THE SYSTEM WILL MOVE THROUGH PRETTY QUICKLY AND ONLY
IMPACT THE CWA IN THE AFTERNOON TO EVENING HOURS WITH A LIGHT
DUSTING OF SNOW. DUE TO THE UNCERTAINTY...WILL MAINTAIN ONLY THE
MENTION OF CHANCE POPS AT THIS TIME BUT LEAN TOWARDS A LATER POINT
IN THE DAY FOR IT TO MOVE THROUGH. CONDITIONS WILL REMAIN NEAR TO
BELOW NORMAL TO CLOSE OUT THE WEEKEND.
RIDGING WILL THEN BUILD IN ON SUNDAY NIGHT AND INTO THE OPENING OF
NEXT WEEK ALLOWING TEMPERATURES TO CREEP UP TO ABOVE FREEZING
BUT...THERE IS SOME QUESTION AS TO HOW WARM IT WILL GET WITH SNOW
REMAINING ON THE GROUND THROUGH THAT TIME. NEXT UPPER LEVEL TROUGH
WILL SWING THROUGH MONDAY NIGHT INTO TUESDAY...LIFTING A SURFACE
FEATURE NORTHEAST THROUGH MICHIGAN INTO THAT TIME. PROFILES
SUGGEST THAT WITH THE MODERATE WARM AIR ADVECTION GOING ON...THAT
PTYPE WILL START AS RAIN BEFORE QUICKLY BECOMING SNOW AS THE
ENTIRE PROFILE DIPS BELOW FREEZING. THE ROLLER COASTER OF TEMPS
RISING AND FALLING WITH WEAK UPPER LEVEL DISTURBANCES ZIPPING
THROUGH ARE EXPECTED TO CONTINUE INTO NEXT WEEKEND.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOWERING CEILINGS LATE TONIGHT/EARLY THURSDAY MORNING...WITH
MVFR CEILINGS BECOMING IFR ON THURSDAY.
* SNOW DEVELOPING BY MID TO LATE THURSDAY MORNING AND CONTINUING
THROUGH THE REMAINDER OF THE FORECAST PERIOD.
* LIKELY A SEVERAL HOUR PERIOD OF IFR TO LIFR VIS THURSDAY
AFTERNOON INTO THE EVENING IN SNOW AND BLOWING SNOW.
KJB
//DISCUSSION...UPDATED 06Z...
NOT MUCH CHANGE FROM PREVIOUS THINKING.
THE FIRST APPRECIABLE WINTER WEATHER EVENT OF THE SEASON IS STILL
SET TO IMPACT THE TERMINALS FOR MUCH OF THE DAY ON THURSDAY AND INTO
THURSDAY NIGHT. THIS IS A RATHER COMPLEX AND DYNAMICAL STORM
SYSTEM THAT LOOKS TO BRING A PERIOD OF MODERATE TO HEAVY SNOW TO
THE NORTHEASTERN ILLINOIS TERMINALS DURING THE AFTERNOON AND
EVENING HOURS ON THURSDAY. THIS WILL BE THE MAIN CONCERN AS SNOW
AND BLOWING SNOW WILL LIKELY LEAD TO A PERIOD OF IFR TO LIFR VIS
AND CIGS THURSDAY AFTERNOON AND INTO THE EVENING.
THE MAIN COLD FRONT IS NOW MOVING ACROSS NORTH CENTRAL IL
NEAR KRFD. THIS FRONT SHOULD MOVE ACROSS NORTHEASTERN
ILLINOIS AFTER 07 UTC TONIGHT. BEHIND THIS FRONT...EXPECT WINDS TO
BECOME GUSTY OUT OF THE NORTHWEST. THE MAIN SURFACE LOW MOVING NORTH
ACROSS THE OHIO VALLEY LATE THIS EVENING...WILL QUICKLY INTENSIFY
DURING THE MORNING ON THURSDAY ACROSS THE GREAT LAKES REGION. THIS
WILL SET THE STAGE FOR GUSTY NORTHWEST WINDS THROUGH THE REMAINDER
OF THE FORECAST PERIOD.
AS FAR AS SNOWFALL...IT APPEARS SNOWFALL WILL BEGIN DURING
THE MID TO LATE MORNING HOURS (AFTER 16 UTC AT THE NORTHEASTERN
ILLINOIS TERMINALS) AS STRONG FORCING FOR ASCENT COMMENCES IN
RESPONSE TO THE ATMOSPHERIC DYNAMICS OF THIS DEEPENING SURFACE
LOW. I EXPECT THE ONSET TIME TO OCCUR AROUND OR SHORTLY AFTER 12
UTC AT KRFD. THE SNOW SHOULD PICK UP IN INTENSITY DURING THE
AFTERNOON HOURS (AFTER 19 UTC) AS THE DYNAMICS REACH A PEAK ALONG
THE LEADING EDGE OF THE COLDEST AIR. THIS STILL APPEARS TO
POSSIBLY RESULT IN A PERIOD OF VISIBILITIES IN SNOW AND BLOWING
SNOW UNDER 1/2 MILE THROUGH THE AFTERNOON AND EARLY EVENING. THE
SNOWFALL SHOULD BEGIN TO ABATE LATER THURSDAY NIGHT INTO FRIDAY
MORNING AS THE STORM SYSTEM SHIFTS EAST ACROSS THE EASTERN GREAT
LAKES.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE WITH CEILINGS AND TRENDS LATE TONIGHT/EARLY
THURSDAY.
* HIGH CONFIDENCE OF SNOW WITH MEDIUM CONFIDENCE OF TIMING AND VIS
TRENDS ON THURSDAY.
* HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...IFR CIGS/VIS EARLY IN SNOW AND BLOWING SNOW. CONDITIONS
IMPROVING THROUGH THE DAY.
SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS.
SUNDAY...VFR.
MONDAY AND TUESDAY...CHANCE OF SNOW SHOWERS WITH MVFR CIGS/VIS.
KJB
&&
.MARINE...
145 PM CST
LOW PRESSURE OVER THE TENNESSEE VALLEY THIS AFTERNOON WILL CURVE
NORTHEAST INTO THE EASTERN GREAT LAKES AND INTENSIFY LATE TONIGHT
AND THURSDAY AS AN ARCTIC AIR MASS PLUNGES SOUTH FROM CENTRAL
CANADA AND THE NORTHERN PLAINS. LIGHT SOUTHEAST WINDS THIS
AFTERNOON WILL BACK NORTHEAST...THEN NORTHWEST AND INCREASE LATE
TONIGHT AND THURSDAY MORNING. WINDS WILL CONTINUE TO RAMP UP
THURSDAY WITH GALE FORCE WINDS OVER THE OPEN WATERS BY LATE
AFTERNOON. WITH WINDS OFFSHORE...WILL LIKELY STAY BELOW GALES FOR
THE ILLINOIS NEARSHORE...BUT EXPECT GALE FORCE WINDS ALONG THE
INDIANA NEARSHORE WATERS. GALES WILL LIKELY CONTINUE THROUGH
FRIDAY AFTERNOON AS THE LOW SPINS OVER THE LOWER LAKES FOR A WHILE
BEFORE MOVING EAST. HIGH PRESSURE WILL BRING DIMINISHING WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. WEAK LOW PRESSURE MOVING
THROUGH THE MIDWEST SATURDAY AFTERNOON AND EVENING WILL HAVE
LITTLE IMPACT ON THE LAKE. AS HIGH PRESSURE MOVES EAST ACROSS THE
LAKES SUNDAY WINDS WILL VEER SOUTH THEN INCREASE SUNDAY NIGHT AND
MONDAY.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-
ILZ019-ILZ021-ILZ032...6 AM THURSDAY TO 4 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-
ILZ020-ILZ022-ILZ023-ILZ033-ILZ039...9 AM THURSDAY TO 9 AM
FRIDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9
AM THURSDAY TO 9 AM FRIDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM
THURSDAY TO 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...NOON
THURSDAY TO MIDNIGHT SATURDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...NOON THURSDAY TO 3 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1007 PM CST WED JAN 11 2012
.DISCUSSION...
840 PM CST
AN INITIAL ANALYSIS HAS BEEN MADE OF 00Z UPPER AIR DATA AS WELL AS
THE 12.00 NAM AND 11.21 SREF. HAVE MADE MODIFICATIONS TO THE START
TIME OF THE SNOWFALL WHERE CONFIDENCE HAS INCREASED...BUT THE
WINTER WEATHER ADVISORY START TIMES STILL LOOK VALID.
RIGHT NOW THE AREA IS NICELY LOCATED UNDER A WEDGE OF SUPPRESSION
AND DRY AIR BETWEEN THE LOW OVER THE OHIO RIVER VALLEY AND THE
INCOMING DIGGING TROUGH AND ARCTIC FRONT. THIS SHOULD HOLD FOR A
WHILE AND LATEST GUIDANCE HAS CAUGHT ONTO THIS WITH SLOWER
PROGRESSION OF THE POST-FRONTAL FORCING AND SNOW ACROSS IA AND
INTO WESTERN MO. THE SURFACE COLD FRONT WILL CONTINUE
EAST...TURNING WINDS NORTHWEST AND BRINGING THE TEMPERATURES DOWN.
ALREADY THE CLEARING HAS ALLOWED FOR COOLING...AND THERE IS ALMOST
NO DOUBT THAT PRECIPITATION TYPE ONSET WILL BE SNOW GIVEN THE
COOLING COLUMN. THE NAM/RUC FORCING AND HRRR REFLECTIVITY HAVE
FORCING FOR PRECIPITATION STILL WEST OF INTERSTATE 39 BY 12Z...AND
STILL WEST OF CHICAGOLAND BY 15Z. THE SREF ENSEMBLE MEMBERS ALSO
HAVE A TIGHTER PACKING THROUGH 15Z FOR INCREASED CONFIDENCE...AND
THIS PACKING IS ON A SLOWER SOLUTION. HAVE ADDED HIGHER TEMPORAL
RESOLUTION POPS TO BETTER DEFINE THE ONSET TIME.
A NICE -37C 500MB COLD POCKET ASSOCIATED WITH THE WESTERN TROUGH
WILL DIG SOUTHEAST INTO THE LATE MORNING AND THE PHASING OF THE
SYSTEMS WILL RAPIDLY BEGIN. LARGE SCALE OMEGA INCREASES ACROSS THE
AREA WITH SATURATION WORKING ITS WAY ACROSS CHICAGOLAND AND
NORTHWEST IN. SO ONSET IN CHICAGOLAND STILL LOOKS TO BE PRIOR TO
NOON...AND LIKELY BETWEEN 9 AM AND NOON FOR MUCH OF THE AREA. THE
AFTERNOON INTO THE EARLY EVENING FOR MOST OF THE FORECAST AREA
CONTINUES TO BE THE PERIOD MOST FAVORED FOR HEAVIER SNOW. THIS IS
BECAUSE OF 1. STRONGER UPPER LEVEL SUPPORT 2. THE TIGHTEST MID-
LEVEL THERMAL GRADIENT SUPPORTING TEMPORARY BURSTS OF
MODERATE/HEAVY ACTIVITY WITHIN BANDS 3. SNOW-TO-WATER EFFICIENCIES
INCREASING WITH A COOLING COLUMN AND DEEPER DENDRITIC
GROWTH...ESPECIALLY AFTER 3 PM...AND 4. LAKE ENHANCED SUPPORT INTO
NORTHWEST INDIANA /WHICH ACTUALLY CONTINUES INTO THE NIGHTTIME
HOURS. THIS IS THE AREA THAT WILL BE PARTICULARLY WATCHED FOR
POSSIBLE UPGRADE TO A WARNING IN TIME.
THE ONLY CHANGE WITH THE THURSDAY AFTERNOON PORTION OF THE
FORECAST WAS TO SLIGHTLY INCREASE SNOWFALL AMOUNTS SOUTH OF
INTERSTATE 80. AMOUNTS ON THURSDAY AFTERNOON ACROSS THE AREA COULD
BE PRETTY HOMOGENEOUS...WITH TEMPORARY BURSTS/BANDS SUPPORTING
LOCALIZED HIGHER AREAS. THE SLOWER ONSET TIME MAY MEAN LESS
SNOWFALL IN THE MORNING ACROSS THE SOUTH THOUGH...SO OVERALL
FORECAST AMOUNTS CAME OUT FAIRLY CLOSE...WITH NO CHANGES FOR
CHICAGOLAND ON TOTALS.
MTF
//PREV DISCUSSION...
243 PM CST
WINTER STORM...TONIGHT THROUGH FRIDAY NIGHT...
HAVE ISSUED WINTER WEATHER ADVISORIES FOR SNOW AND BLOWING SNOW
WHICH WILL COVER THE CAW FOR THURSDAY INTO EARLY FRIDAY.
STRONG SHORT WAVE TROUGH DIGGING SOUTHEAST ACROSS THE NORTHERN
PLAINS WILL CONTINUE TO CARVE OUT A DEEP UPPER TROUGH ACROSS THE
CENTRAL CONUS TONIGHT/THURSDAY...WITH A CLOSED UPPER LOW
DEVELOPING ACROSS THE MID-MISSISSIPPI VALLEY. PRE-EXISTING SURFACE
LOW PRESSURE OVER THE OHIO VALLEY WILL DEEPEN AND LIFT NORTH INTO
THE GREAT LAKES REGION IN RESPONSE TO DEVELOPING UPPER LOW...AND
STRONG LOW LEVEL BAROCLINICITY WITH INTRUSION OF LOW LEVEL ARCTIC
AIR. UPPER DIVERGENCE IN LEFT EXIT REGION OF CYCLONICALLY CURVED
UPPER JET STREAK WILL ALSO AID IN DEVELOPING DEEP SYNOPTIC SCALE
ASCENT ACROSS THE THE AREA. 12Z MODEL GUIDANCE IS GENERALLY IN
VERY GOOD AGREEMENT IN DEPICTION OF EVOLUTION OF SYSTEM OVER THE
NEXT 36 HOURS...SAVE FOR SOME QPF DIFFERENCES...WITH THE WRF-NAM
BEING MORE GENEROUS WITH THE PRECIP/SNOW AMOUNTS. GUIDANCE DOES
INDICATE THAT THE GREATEST AMOUNTS WILL LIKELY BE ACROSS NORTHEAST
IL/NORTHWEST INDIANA WHERE SOME LAKE-ENHANCEMENT POTENTIAL
EXISTS...AND WHERE LARGER SCALE DEFORMATION AXIS EVENTUALLY SETS
UP AS SYSTEM DEEPENS AND MOVES OFF TO THE EAST-NORTHEAST LATER
THURSDAY AND THURSDAY NIGHT. WHILE FORCING DECREASES QUICKLY LATE
THURSDAY NIGHT...LIGHTER SNOW/SNOW SHOWERS IS/ARE EXPECTED TO
CONTINUE INTO FRIDAY MORNING. THE PERIOD MOST FAVORABLE FOR MORE
SIGNIFICANT ACCUMULATION WILL SLIDE FROM WEST TO EAST ACROSS THE
AREA FROM MID THURSDAY MORNING THROUGH VERY EARLY FRIDAY EVENING.
SNOWFALL AMOUNTS ARE TRICKY WITH THIS SYSTEM...LARGELY DUE TO DEGREE
OF COOLING OF THE COLUMN AS DEPTH OF ARCTIC AIR INCREASES LATE
THURSDAY AND THURSDAY NIGHT...AS WELL AS DUE TO AFOREMENTIONED
POTENTIAL FOR LAKE-ENHANCEMENT IN COUNTIES BORDERING LAKE MICHIGAN.
MODEL SNOW/LIQUID RATIOS RANGE FROM 10:1 AT ONSET...TO 15 OR 20:1
LATER IN THE EVENT. HAVE GENERALLY USED HPC QPF...WITH A LITTLE
BLENDING OF WRF OUTPUT...AND RATIOS RANGING FROM 10:1 TO 17:1
THROUGH THE EVENT FOR SNOWFALL FORECAST. THIS YIELDS ROUGHLY 3-5
INCHES ACROSS SOUTHWESTERN CWA...TO 4-6 INCHES FOR NORTHEAST CWA
COUNTIES NOT ALONG THE LAKE...TO 4-8 INCHES FOR THE LAKE ADJOINING
COUNTIES. ACCUMULATING SNOWFALL IS EXPECTED TO BE OVER NEARLY A 24
HOUR PERIOD...THOUGH EXPECT IT WILL FALL JUST SHORT OF THE 6
INCHES IN 12 HOURS OR 8 INCHES IN 24 HOURS CRITERIA FOR WINTER
STORM WARNING. BASED ON THIS...AND COLLABORATION WITH MKX/ILX AND
IWX HAVE ELECTED TO ISSUE A WINTER WEATHER ADVISORY FOR SNOW AND
BLOWING SNOW. NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 20-25
MPH THURSDAY AFTERNOON...AND MAY GUST 30-35 MPH THURSDAY NIGHT AS
LOW DEEPENS OFF TO OUR EAST. THIS WILL LIKELY RESULT IN
SIGNIFICANT BLOWING AND DRIFTING SNOW PARTICULARLY IN OPEN/RURAL
AREAS. IN ADDITION TO THE BLOWING/DRIFTING ISSUES...THESE WINDS
WILL COMBINE WITH ARCTIC AIR TO PRODUCE WIND CHILLS IN THE ZERO TO
-10 F RANGE THURSDAY NIGHT/EARLY FRIDAY MORNING.
THE POTENTIAL FOR LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO
NORTHWEST INDIANA ON FRIDAY...THOUGH FORECAST SOUNDINGS DEPICT WINDS
GRADUALLY BACKING MORE WEST-NORTHWEST WHICH SHOULD FORCE STRONGER
LAKE EFFECT BANDS INTO WFOS GRR/IWX AREAS.
RATZER
LONGER TERM...FRIDAY THROUGH EARLY NEXT WEEK...
THE CLOSED CIRCULATION ALOFT THAT WILL BRING THE BLAST OF WINTER
WEATHER WILL MOVE ACROSS THE NORTHEASTERN STATES BY THE AFTERNOON ON
FRIDAY. IN THE WAKE OF THIS SYSTEM WILL BE WEAK SURFACE RIDGING THAT
WILL FLIP WINDS BACK TO THE SOUTHWEST AND ADVECT IN A LITTLE WARMER
AIR FROM THE COLDER AIRMASS THAT WAS DUMPED ACROSS THE REGION. WHILE
STILL CHILLY...HIGHS WILL MANAGE TO GET WITHIN REACH OF NORMAL FOR
THIS TIME OF YEAR ON SATURDAY...WITH GENERALLY LOWER 30S EXPECTED
SOUTH OF I-80 AND TEMPS JUST BELOW NORMAL TO THE NORTH. INTO THE
EVENING ANOTHER CLIPPER WILL DIVE OUT OF THE NORTHERN PLAINS AND
ACROSS THE CWA THROUGH EARLY SUNDAY MORNING. THERE IS STILL A
LITTLE UNCERTAINTY WITH RESPECT TO THE TRACK OF THE CLIPPER MOVING
THROUGH...AS ALL GUIDANCE /ECMWF - GEMNH - GFS/ HAVE TRENDED A
LITTLE FURTHER SOUTH OVER THE LAST FEW RUNS...SO CONFIDENCE IS NOT
THE HIGHEST WITH THE LIKELIHOOD ON WHERE THE LOW WILL TRACK.
REGARDLESS...THE SYSTEM WILL MOVE THROUGH PRETTY QUICKLY AND ONLY
IMPACT THE CWA IN THE AFTERNOON TO EVENING HOURS WITH A LIGHT
DUSTING OF SNOW. DUE TO THE UNCERTAINTY...WILL MAINTAIN ONLY THE
MENTION OF CHANCE POPS AT THIS TIME BUT LEAN TOWARDS A LATER POINT
IN THE DAY FOR IT TO MOVE THROUGH. CONDITIONS WILL REMAIN NEAR TO
BELOW NORMAL TO CLOSE OUT THE WEEKEND.
RIDGING WILL THEN BUILD IN ON SUNDAY NIGHT AND INTO THE OPENING OF
NEXT WEEK ALLOWING TEMPERATURES TO CREEP UP TO ABOVE FREEZING
BUT...THERE IS SOME QUESTION AS TO HOW WARM IT WILL GET WITH SNOW
REMAINING ON THE GROUND THROUGH THAT TIME. NEXT UPPER LEVEL TROUGH
WILL SWING THROUGH MONDAY NIGHT INTO TUESDAY...LIFTING A SURFACE
FEATURE NORTHEAST THROUGH MICHIGAN INTO THAT TIME. PROFILES
SUGGEST THAT WITH THE MODERATE WARM AIR ADVECTION GOING ON...THAT
PTYPE WILL START AS RAIN BEFORE QUICKLY BECOMING SNOW AS THE
ENTIRE PROFILE DIPS BELOW FREEZING. THE ROLLER COASTER OF TEMPS
RISING AND FALLING WITH WEAK UPPER LEVEL DISTURBANCES ZIPPING
THROUGH ARE EXPECTED TO CONTINUE INTO NEXT WEEKEND.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 04Z...
* LOWERING CEILINGS LATE TONIGHT/EARLY THURSDAY MORNING...WITH
MVFR CEILINGS BECOMING IFR ON THURSDAY.
* SNOW DEVELOPING BY MID TO LATE THURSDAY MORNING AND CONTINUING
THROUGH THE REMAINDER OF THE FORECAST PERIOD.
* LIKELY SEVERAL HOUR PERIOD OF IFR TO LIFR VIS THURSDAY AFTERNOON
INTO THE EVENING IN SNOW AND BLOWING SNOW.
KJB
//DISCUSSION...UPDATED 00Z...
THE FIRST APPRECIABLE WINTER WEATHER EVENT OF THE SEASON IS SET TO
IMPACT THE TERMINALS FOR MUCH OF THE DAY ON THURSDAY AND INTO
THURSDAY NIGHT. THIS IS A RATHER COMPLEX AND DYNAMICAL STORM
SYSTEM THAT LOOKS TO BRING A PERIOD OF MODERATE TO HEAVY SNOW TO
THE NORTHEASTERN ILLINOIS TERMINALS DURING THE AFTERNOON AND
EVENING HOURS ON THURSDAY. THIS WILL BE THE MAIN CONCERN AS SNOW
AND BLOWING SNOW WILL LIKELY LEAD TO A PERIOD OF IFR TO LIFR VIS
AND CIGS THURSDAY AFTERNOON AND INTO THE EVENING.
THE MAIN COLD FRONT IS NOW MOVING ACROSS EASTERN IOWA. THIS FRONT
SHOULD MOVE ACROSS NORTHEASTERN ILLINOIS AFTER 06 UTC TONIGHT.
BEHIND THIS FRONT...EXPECT WINDS TO BECOME GUSTY OUT OF THE
NORTHWEST LATER TONIGHT. THE MAIN SURFACE LOW WILL QUICKLY INTENSIFY
DURING THE MORNING ON THURSDAY ACROSS THE GREAT LAKES REGION. THIS
WILL SET THE STAGE FOR GUSTY NORTHWEST WINDS THROUGH THE REMAINDER
OF THE FORECAST PERIOD.
AS FAR AS SNOWFALL...IT APPEARS SNOWFALL WILL BEGIN DURING
THE MID TO LATE MORNING HOURS (AFTER 15 UTC AT THE NORTHEASTERN
ILLINOIS TERMINALS) AS STRONG FORCING FOR ASCENT COMMENCES IN
RESPONSE TO THE ATMOSPHERIC DYNAMICS OF THIS DEEPENING SURFACE LOW.
EXPECT THE ONSET TIME A FEW HOURS SOONER AT KRFD. THE SNOW SHOULD
PICK UP IN INTENSITY DURING THE AFTERNOON HOURS (AFTER 19 UTC) AS
THE DYNAMICS REACH A PEAK ALONG THE LEADING EDGE OF THE COLDEST AIR.
THIS COULD LEAD TO A PERIOD OF VISIBILITIES IN SNOW AND BLOWING SNOW
UNDER 1/2 MILE THROUGH THE AFTERNOON AND EARLY EVENING. THE SNOWFALL
SHOULD BEGIN TO ABATE LATER THURSDAY NIGHT INTO FRIDAY MORNING AS
THE STORM SYSTEM SHIFTS EAST ACROSS THE EASTERN GREAT LAKES.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 04Z...
* HIGH CONFIDENCE WITH CEILINGS AND TRENDS LATE TONIGHT/EARLY
THURSDAY.
* HIGH CONFIDENCE OF SNOW WITH MEDIUM CONFIDENCE OF TIMING AND VIS
TRENDS ON THURSDAY.
* HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...IFR CIGS/VIS EARLY IN SNOW AND BLOWING SNOW. CONDITIONS
IMPROVING THROUGH THE DAY.
SATURDAY...CHANCE OF SNOW WITH MVFR CIGS/VIS.
SUNDAY...VFR.
MONDAY AND TUESDAY...CHANCE OF SNOW SHOWERS WITH MVFR CIGS/VIS.
KJB
&&
.MARINE...
145 PM CST
LOW PRESSURE OVER THE TENNESSEE VALLEY THIS AFTERNOON WILL CURVE
NORTHEAST INTO THE EASTERN GREAT LAKES AND INTENSIFY LATE TONIGHT
AND THURSDAY AS AN ARCTIC AIR MASS PLUNGES SOUTH FROM CENTRAL
CANADA AND THE NORTHERN PLAINS. LIGHT SOUTHEAST WINDS THIS
AFTERNOON WILL BACK NORTHEAST...THEN NORTHWEST AND INCREASE LATE
TONIGHT AND THURSDAY MORNING. WINDS WILL CONTINUE TO RAMP UP
THURSDAY WITH GALE FORCE WINDS OVER THE OPEN WATERS BY LATE
AFTERNOON. WITH WINDS OFFSHORE...WILL LIKELY STAY BELOW GALES FOR
THE ILLINOIS NEARSHORE...BUT EXPECT GALE FORCE WINDS ALONG THE
INDIANA NEARSHORE WATERS. GALES WILL LIKELY CONTINUE THROUGH
FRIDAY AFTERNOON AS THE LOW SPINS OVER THE LOWER LAKES FOR A WHILE
BEFORE MOVING EAST. HIGH PRESSURE WILL BRING DIMINISHING WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. WEAK LOW PRESSURE MOVING
THROUGH THE MIDWEST SATURDAY AFTERNOON AND EVENING WILL HAVE
LITTLE IMPACT ON THE LAKE. AS HIGH PRESSURE MOVES EAST ACROSS THE
LAKES SUNDAY WINDS WILL VEER SOUTH THEN INCREASE SUNDAY NIGHT AND
MONDAY.
ALLSOPP
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-
ILZ019-ILZ021-ILZ032...6 AM THURSDAY TO 4 AM FRIDAY.
WINTER WEATHER ADVISORY...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-
ILZ020-ILZ022-ILZ023-ILZ033-ILZ039...9 AM THURSDAY TO 9 AM
FRIDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...9
AM THURSDAY TO 9 AM FRIDAY.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM
THURSDAY TO 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...NOON
THURSDAY TO MIDNIGHT SATURDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...NOON THURSDAY TO 3 PM
THURSDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
345 PM EST THU JAN 12 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...A STRONG COLD FRONT WILL SWEEP ACROSS CENTRAL
INDIANA...USHERING AN ARCTIC AIRMASS INTO CENTRAL INDIANA FOR THE
NEXT FEW DAYS. AN UPPER LEVEL LOW PRESSURE SYSTEM WILL EXIT THE
STATE TONIGHT...HOWEVER...MOISTURE WRAPPING AROUND THE LOW WILL
LIKELY RESULT IN SCATTERED SNOW SHOWERS...PARTICULARLY THIS
EVENING.
THE STRONG LOW WILL LINGER ACROSS THE NORTHEAST UNITED STATE ON
FRIDAY...PROVIDING A COLD...ARCTIC FLOW OF AIR TO CENTRAL INDIANA.
A FEW SNOW SHOWERS CANNOT BE RULED OUT ON FRIDAY.
A QUICK MOVING RIDGE OF HIGH PRESSURE WILL PUSH ACROSS THE STATE
FRIDAY NIGHT AND SATURDAY...PROVIDING MORE COLD...CLOUDY...BUT DRY
WEATHER.
ANOTHER UPPER LEVEL DISTURBANCE WILL PUSH INTO THE STATE FROM THE
NORTHWEST ON SATURDAY NIGHT AND SUNDAY...AND THIS MAY PROVIDE
ANOTHER BRIEF ROUND OF SNOW SHOWERS.
THE COLD AIR IS EXPECTED TO EXIT EARLY NEXT WORK WEEK AS THE FLOW
ALOFT BECOMES MORE WESTERLY USHERING MILD PACIFIC AIR BACK TO THE
OHIO VALLEY.
&&
.NEAR TERM /TONIGHT/...
SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHERN ONTARIO EARLY
THIS AFTERNOON AND A COLD FRONT STRETCHED SOUTH ACROSS WESTERN
OHIO. MUCH COLDER AIR WAS FOUND ACROSS CENTRAL ILLINOIS AND
WESTERN CENTRAL INDIANA WHERE TEMPERATURES WERE IN THE TEENS.
WATER VAPOR IMAGERY INDICATE THE UPPER LOW OVER SE
MISSOURI...DRIVING EASTWARD. RADAR TRENDS SHOW MUCH DRIER AIR
WRAPPING IN TO THE SYSTEM FROM THE SOUTHWEST. MODELS AGREE THAT
THE UPPER SYSTEM WILL PUSH ACROSS THE STATE TONIGHT...HOWEVER BEST
FORCING IS LOST AFTER 06Z. POTENTIAL VORTICITY MUCH DRIER ARRIVING
ALONG WITH SUBSIDENCE AFTER 06Z...HOWEVER FORECAST SOUNDINGS
CONTINUE TO SUGGEST DEEP SATURATION. ALSO 850MB POTENTIAL
TEMPERATURE SURFACE SHOWS A WEAK TROWAL WORKING ACROSS THE
STATE...BUT EXITING AFTER 06Z. THUS WILL KEEP POPS GOING INTO THE
EVENING HOURS AS FORCING WILL BE FAVORABLE...HOWEVER WILL TAPER
POPS OFF AFTER 06Z AS BEST DYNAMIC SHIFT WELL TO THE NORTHEAST.
GIVEN THE DRY AIR WORKING INTO THE AREA ALONG WITH THE FORCING
ENDING BY 06Z...FEEL THAT SNOW AMOUNTS ARE MORE LIKELY TO END UP
AT THE LOWER END OF THE ADVISORY CRITERIA. AS FOR TEMPS WILL TREND
COOLER THAN MAVMOS GIVEN THE STRONG COLD AIR ADVECTION.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
MODELS REMAIN IN PRETTY GOOD OVERALL AGREEMENT DURING THIS PERIOD
AND WILL USE A BLEND.
BROAD CYCLONIC FLOW WILL REMAIN IN PLACE ON FRIDAY AS THE UPPER
LOW DEPARTS AND FORECAST SOUNDINGS INDICATE DEEP SATURATION BUT
MINIMAL FORCING THROUGH 18Z. SOUNDINGS BEGIN TO DRY OUT AFTER 18Z AS
THE COLD ARCTIC AIR MASS BEGINS TO SETTLE IN. THUS WILL CONTINUE
LOW CHANCE POPS DURING THE MORNING HOURS...BUT TAPER OFF TO A DRY
FORECAST IN THE AFTERNOON AS DRIER AIR ARRIVES. WILL TREND COLDER
THAN MAVMOS FOR HIGHS.
COLD NORTHWEST FLOW WILL PERSIST ALOFT ON FRIDAY NIGHT AND ANOTHER
WEAK DISTURBANCE WILL PUSH ACROSS THE STATE. HOWEVER MOISTURE IS
LIMITED AND NO PRECIP WILL BE EXPECTED. FURTHERMORE WITH A FRESH
SNOW COVER AND 850MB TEMPS THAT HAVE FALLEN TO NEAR -11C...WILL
TREND LOWS COLDER THAN MAVMOS.
ANOTHER STRONGER UPPER DISTURBANCE WILL PUSH INTO THE AREA ON
SATURDAY AND SATURDAY NIGHT. GFS IS MUCH DRIER THAN THE NAM. GIVEN
THE EXPECTED FORCING...FEEL THAT THE NAM HANDLES THE SITUATION
HERE AND LOW POPS APPEAR NEEDED. WITH COLD AIR IN PLACE PRECIP
TYPE WILL BE SNOW AS THIS CLIPPER MOVES THROUGH. AGAIN GIVEN THE
EXPECTED CLOUDS WILL TREND HIGHS ON SATURDAY COLDER THAN MAVMOS
AND STICK CLOSE ON LOWS.
A RIDGE OF HIGH PRESSURE WILL THEN BUILD UP ACROSS CENTRAL INDIANA
ON SUNDAY AS WARM AIR ADVECTION BEGINS AS THE DOME OF COLD AIR
BEGINS TO DEPART TO THE EAST. STRONG SOUTHERLY FLOW WILL SET UP BY
SUNDAY EVENING AS HIGH PRESSURE SETTLES ACROSS APPALACHIA AND A LOW
DEVELOPS OVER THE WESTERN PLAINS STATES. WILL AIM FOR A DRY SUNDAY
ALONG WITH TEMPS WARMER THAN MEXMOS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LONGER RANGE MODEL DATA SUGGEST A PROGRESSIVE AND POTENTIALLY
ENERGETIC PATTERN ACROSS THE COUNTRY WITH JET STREAM WINDS PROGGED
IN THE 120-170KT RANGE THROUGHOUT MOST OF THE EXTENDED PERIOD.
ENSEMBLES ARE KEYING ON TWO SYSTEMS...ONE PASSING THROUGH IN THE
EARLY TO MIDDLE PARTS OF NEXT WEEK AND ANOTHER POSSIBLY AROUND
THURSDAY. AT THIS TIME...THE FIRST SYSTEM LOOKS TO BE THE STRONGER
OF THE TWO. WILL CONTINUE WITH POPS FROM MONDAY THROUGH TUESDAY
NIGHT...WITH THE HIGHEST POPS MONDAY NIGHT. JUST ABOUT ALL OF THE
ENSEMBLES TAKE THE SURFACE LOW NORTH OF THE LOCAL AREA...SO THIS
LOOKS TO BE MAINLY A RAIN EVENT...WITH SOME POTENTIAL FOR LIGHT SNOW
NEAR THE END OF THE EVENT.
SYSTEM ON THURSDAY LOOKS TO BE MORE OF A CLIPPER TYPE...AS MAIN
UPPER TROUGH AXIS IS PROGGED TO BE NEAR THE EAST COAST. WILL GO WITH
CHANCE POPS FOR LIGHT SNOW AT THAT TIME.
&&
.AVIATION /DISCUSSION FOR THE 122100Z TAF UPDATES/...
THE HEAVIER SNOW HAS ENDED FOR NOW...SO RAISED THE VISIBILITIES TO
P6SM WITH FLURRIES AND RAISED CEILINGS TO MVFR. GUSTS ARE ALSO
PICKING UP ON CUE SO TWEAKED WITH WINDS JUST A BIT. PREVIOUS
DISCUSSION FOLLOWS...
RADAR TRENDS SUGGEST THE ARRIVAL OF THE SNOW AT KIND MAY BE SOONER
THAN WHAT IS CURRENTLY IN THE FORECAST. WILL NUDGE UP THE ARRIVAL OF
THE SNOW AND ASSOCIATED IFR VISIBILITY RESTRICTIONS TO AROUND
121600Z. UPSTREAM OBSERVATIONS ACROSS ILLINOIS SUGGEST POTENTIAL FOR
A PERIOD OF LIFR VISIBILITY RESTRICTIONS LATER THIS AFTERNOON. MAY
NEED TO ADD THIS IN LATER UPDATES. PREVIOUS DISCUSSION FOLLOWS.
SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY
MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW
HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND
SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF
ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE
VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE
INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF
LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL
THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS
INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND
THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL.
LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW
SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A
HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE
WIDESPREAD LOW MVFR.
WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD
SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD
START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED
SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30
KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE
WESTERLY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...CP/JAS/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
210 PM EST THU JAN 12 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW
&&
.SYNOPSIS...A STRONG COLD FRONT WILL SWEEP ACROSS CENTRAL
INDIANA...USHERING AN ARCTIC AIRMASS INTO CENTRAL INDIANA FOR THE
NEXT FEW DAYS. AN UPPER LEVEL LOW PRESSURE SYSTEM WILL EXIT THE
STATE TONIGHT...HOWEVER...MOISTURE WRAPPING AROUND THE LOW WILL
LIKELY RESULT IN SCATTERED SNOW SHOWERS...PARTICULARLY THIS
EVENING.
THE STRONG LOW WILL LINGER ACROSS THE NORTHEAST UNITED STATE ON
FRIDAY...PROVIDING A COLD...ARCTIC FLOW OF AIR TO CENTRAL INDIANA.
A FEW SNOW SHOWERS CANNOT BE RULED OUT ON FRIDAY.
A QUICK MOVING RIDGE OF HIGH PRESSURE WILL PUSH ACROSS THE STATE
FRIDAY NIGHT AND SATURDAY...PROVIDING MORE COLD...CLOUDY...BUT DRY WEATHER.
ANOTHER UPPER LEVEL DISTURBANCE WILL PUSH INTO THE STATE FROM THE
NORTHWEST ON SATURDAY NIGHT AND SUNDAY...AND THIS MAY PROVIDE
ANOTHER BRIEF ROUND OF SNOW SHOWERS.
THE COLD AIR IS EXPECTED TO EXIT EARLY NEXT WORK WEEK AS THE FLOW
ALOFT BECOMES MORE WESTERLY USHERING MILD PACIFIC AIR BACK TO THE
OHIO VALLEY.
&&
.NEAR TERM /TONIGHT/...
SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHERN ONTARIO EARLY
THIS AFTERNOON AND A COLD FRONT STRETCHED SOUTH ACROSS WESTERN
OHIO. MUCH COLDER AIR WAS FOUND ACROSS CENTRAL ILLINOIS AND
WESTERN CENTRAL INDIANA WHERE TEMPERATURES WERE IN THE TEENS.
WATER VAPOR IMAGERY INDICATE THE UPPER LOW OVER SE
MISSOURI...DRIVING EASTWARD. RADAR TRENDS SHOW MUCH DRIER AIR
WRAPPING IN TO THE SYSTEM FROM THE SOUTHWEST. MODELS AGREE THAT
THE UPPER SYSTEM WILL PUSH ACROSS THE STATE TONIGHT...HOWEVER BEST
FORCING IS LOST AFTER 06Z. POTENTIAL VORTICITY MUCH DRIER ARRIVING
ALONG WITH SUBSIDENCE AFTER 06Z...HOWEVER FORECAST SOUNDINGS
CONTINUE TO SUGGEST DEEP SATURATION. ALSO 850MB POTENTIAL
TEMPERATURE SURFACE SHOWS A WEAK TROWAL WORKING ACROSS THE
STATE...BUT EXITING AFTER 06Z. THUS WILL KEEP POPS GOING INTO THE
EVENING HOURS AS FORCING WILL BE FAVORABLE...HOWEVER WILL TAPER
POPS OFF AFTER 06Z AS BEST DYNAMIC SHIFT WELL TO THE NORTHEAST.
GIVEN THE DRY AIR WORKING INTO THE AREA ALONG WITH THE FORCING
ENDING BY 06Z...FEEL THAT SNOW AMOUNTS ARE MORE LIKELY TO END UP
AT THE LOWER END OF THE ADVISORY CRITERIA. AS FOR TEMPS WILL TREND
COOLER THAN MAVMOS GIVEN THE STRONG COLD AIR ADVECTION.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
MODELS REMAIN IN PRETTY GOOD OVERALL AGREEMENT DURING THIS PERIOD
AND WILL USE A BLEND.
BROAD CYCLONIC FLOW WILL REMAIN IN PLACE ON FRIDAY AS THE UPPER
LOW DEPARTS AND FORECAST SOUNDINGS INDICATE DEEP SATURATION BUT
MINIMAL FORCING THROUGH 18Z. SOUNDINGS BEGIN TO DRY OUT AFTER 18Z AS
THE COLD ARCTIC AIR MASS BEGINS TO SETTLE IN. THUS WILL CONTINUE
LOW CHANCE POPS DURING THE MORNING HOURS...BUT TAPER OFF TO A DRY
FORECAST IN THE AFTERNOON AS DRIER AIR ARRIVES. WILL TREND COLDER
THAN MAVMOS FOR HIGHS.
COLD NORTHWEST FLOW WILL PERSIST ALOFT ON FRIDAY NIGHT AND ANOTHER
WEAK DISTURBANCE WILL PUSH ACROSS THE STATE. HOWEVER MOISTURE IS
LIMITED AND NO PRECIP WILL BE EXPECTED. FURTHERMORE WITH A FRESH
SNOW COVER AND 850MB TEMPS THAT HAVE FALLEN TO NEAR -11C...WILL
TREND LOWS COLDER THAN MAVMOS.
ANOTHER STRONGER UPPER DISTURBANCE WILL PUSH INTO THE AREA ON
SATURDAY AND SATURDAY NIGHT. GFS IS MUCH DRIER THAN THE NAM. GIVEN
THE EXPECTED FORCING...FEEL THAT THE NAM HANDLES THE SITUATION
HERE AND LOW POPS APPEAR NEEDED. WITH COLD AIR IN PLACE PRECIP
TYPE WILL BE SNOW AS THIS CLIPPER MOVES THROUGH. AGAIN GIVEN THE
EXPECTED CLOUDS WILL TREND HIGHS ON SATURDAY COLDER THAN MAVMOS
AND STICK CLOSE ON LOWS.
A RIDGE OF HIGH PRESSURE WILL THEN BUILD UP ACROSS CENTRAL INDIANA
ON SUNDAY AS WARM AIR ADVECTION BEGINS AS THE DOME OF COLD AIR
BEGINS TO DEPART TO THE EAST. STRONG SOUTHERLY FLOW WILL SET UP BY
SUNDAY EVENING AS HIGH PRESSURE SETTLES ACROSS APPALACHIA AND A LOW
DEVELOPS OVER THE WESTERN PLAINS STATES. WILL AIM FOR A DRY SUNDAY
ALONG WITH TEMPS WARMER THAN MEXMOS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LONGER RANGE MODEL DATA SUGGEST A PROGRESSIVE AND POTENTIALLY
ENERGETIC PATTERN ACROSS THE COUNTRY WITH JET STREAM WINDS PROGGED
IN THE 120-170KT RANGE THROUGHOUT MOST OF THE EXTENDED PERIOD.
ENSEMBLES ARE KEYING ON TWO SYSTEMS...ONE PASSING THROUGH IN THE
EARLY TO MIDDLE PARTS OF NEXT WEEK AND ANOTHER POSSIBLY AROUND
THURSDAY. AT THIS TIME...THE FIRST SYSTEM LOOKS TO BE THE STRONGER
OF THE TWO. WILL CONTINUE WITH POPS FROM MONDAY THROUGH TUESDAY
NIGHT...WITH THE HIGHEST POPS MONDAY NIGHT. JUST ABOUT ALL OF THE
ENSEMBLES TAKE THE SURFACE LOW NORTH OF THE LOCAL AREA...SO THIS
LOOKS TO BE MAINLY A RAIN EVENT...WITH SOME POTENTIAL FOR LIGHT SNOW
NEAR THE END OF THE EVENT.
SYSTEM ON THURSDAY LOOKS TO BE MORE OF A CLIPPER TYPE...AS MAIN
UPPER TROUGH AXIS IS PROGGED TO BE NEAR THE EAST COAST. WILL GO WITH
CHANCE POPS FOR LIGHT SNOW AT THAT TIME.
&&
.AVIATION /DISCUSSION FOR THE 121500Z KIND TAF UPDATE/...
RADAR TRENDS SUGGEST THE ARRIVAL OF THE SNOW AT KIND MAY BE SOONER
THAN WHAT IS CURRENTLY IN THE FORECAST. WILL NUDGE UP THE ARRIVAL OF
THE SNOW AND ASSOCIATED IFR VISIBILITY RESTRICTIONS TO AROUND
121600Z. UPSTREAM OBSERVATIONS ACROSS ILLINOIS SUGGEST POTENTIAL FOR
A PERIOD OF LIFR VISIBILITY RESTRICTIONS LATER THIS AFTERNOON. MAY
NEED TO ADD THIS IN LATER UPDATES. PREVIOUS DISCUSSION FOLLOWS.
SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY
MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW
HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND
SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF
ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE
VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE
INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF
LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL
THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS
INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND
THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL.
LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW
SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A
HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE
WIDESPREAD LOW MVFR.
WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD
SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD
START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED
SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30
KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE
WESTERLY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...CP/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1134 AM EST THU JAN 12 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A STRONG COLD FRONT WILL SWEEP ACROSS INDIANA THIS MORNING. THEN A
STRONG UPPER LOW WILL MOVE ACROSS SOUTHERN INDIANA THIS EVENING AND
TO THE EASTERN GREAT LAKES FRIDAY. AN UPPER LEVEL DISTURBANCE WILL
TRACK ACROSS THE MID MISSISSIPPI AND OHIO VALLEYS LATE SATURDAY.
IN THE EXTENDED THE UPPER FLOW BECOMES MORE ZONAL EARLY NEXT WEEK
CAUSING TEMPERATURES TO MODERATE. AN UPPER DISTURBANCE WILL AFFECT
OUR WEATHER BY LATE MONDAY AND A COLD FRONT WILL MOVE ACROSS OUR
REGION TUESDAY. HIGH PRESSURE BEHIND THIS FRONT WILL BUILD ACROSS
OUR REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THIS AFTERNOON/...
RADAR TRENDS INDICATE SNOW SHOWERS PUSHING ACROSS THE FORECAST
AREA AHEAD OF THE ARCTIC FRONT. VERY COLD AIR...IN THE TEENS...WAS
FOUND BEHIND THE FRONT AND IS EXPECTED TO ADVECT ACROSS THE
FORECAST AREA THIS AFTERNOON. HAVE TRENDED HOURLY TEMPERATURE
GRIDS MUCH LOWER THIS AFTERNOON REFLECTING THIS CHANGE. ALSO HAVE
RAISED POPS TO CATEGORICAL BASED UPON RECENT RADAR TRENDS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MODELS ARE INDICATING THAT BEST TIME FRAME FOR SNOW ACCUMULATION
WILL BE FRI 00-06Z TONIGHT. BEST QVECTOR CONVERGENCE AND
FRONTOGENETIC BANDING WILL BE ACROSS THE NORTHERN COUNTIES OF
FORECAST AREA. TOTAL ACCUMULATIONS BY FRIDAY MORNING WILL RANGE FROM
1 TO 2 INCHES SOUTHERN SECTIONS...2 TO 3 INCHES ALONG THE INTERSTATE
70 CORRIDOR TO AROUND 3 TO 5 INCHES NEAR KOKOMO.
ISENTROPIC LIFT WILL ALSO BE BEST OVER THE NORTHERN COUNTIES...WITH
MOISTURE LACKING OVER THE SOUTHERN COUNTIES. SATURATION IN THE
DENDRITIC GROWTH ZONE WAS NOT OVERLY IMPRESSIVE EITHER...WHICH WILL
LIMIT SNOWFALL.
WRAPAROUND MOISTURE WILL RESULT IN SNOW SHOWERS ACROSS THE
NORTHEAST QUADRANT THROUGH FRIDAY MORNING. HOWEVER...THE MAIN
THREAT ON FRIDAY WILL BE THE STRONG WEST WINDS WITH SUSTAINED
SPEEDS OF 15 TO 25 MPH AND GUSTS TO 30 MPH. THIS WILL CREATE
BLOWING AND DRIFTING SNOW AND REDUCED VISIBILITIES. AS A
RESULT...CARRIED THE WINTER WEATHER ADVISORY TO FRI 18Z.
COLD ARCTIC AIR WILL SIT ACROSS CENTRAL INDIANA IN WAKE OF THIS
SYSTEM INTO THE WEEKEND. MODELS HAVE TRENDED A LITTLE COLDER FRIDAY
THROUGH SATURDAY AND WITH A COUPLE OF INCHES OF SNOW COVER...SEE NO
REASON NOT TO FOLLOW THIS TREND.
WEAK AREA OF HIGH PRESSURE WILL MOVE ACROSS OUR REGION LATE FRIDAY
NIGHT AND EARLY SATURDAY. THEN MODELS BRING A FAST MOVING CLIPPER
INTO THE OHIO VALLEY BY LATE SATURDAY. WESTERN AND SOUTH CENTRAL
SECTIONS COULD SEE UP TO AN INCH BY SATURDAY EVENING BEFORE THIS
SYSTEM MOVES OFF QUICKLY TO THE EAST SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
UPPER RIDGING BUILDS IN AND MOVES ACROSS THE AREA SUNDAY AND SUNDAY
NIGHT BRINGING IN SOME DRY AIR AND SCATTERING OUT SKY COVER. DURING
THE DAY MONDAY THE AREA WILL BE ON THE BACK SIDE OF THE RIDGE WITH
AN UPPER TROUGH TO THE EAST AND A COLD FRONT FIRMING UP OVER THE
PLAINS. THIS WILL ALLOW WARM ADVECTION TO RAMP UP AND ISENTROPIC
LIFT TO ENTER THE AREA BRINGING SMALL CHANCES FOR RAIN ON MONDAY. BY
MONDAY NIGHT THE LIFT REALLY INCREASES AHEAD OF THE COLD FRONT AND
MOISTURE SHOULD BE STREAMING UP FROM THE GULF ON A 50+ KT LOW LEVEL
JET. THOUGHT THE LIKELY POPS FROM THE ALLBLEND MATCHED UP WITH THIS
WELL. GFS AND ECMWF HAVE A BIT OF A DIFFERENCE IN THE TIMING OF THE
COLD FRONTAL PASSAGE TUESDAY WHICH COULD MAKE A DIFFERENCE IN HIGH
TEMPERATURES FOR THE DAY AS WELL AS HOW LONG PRECIPITATION CHANCES
WILL LAST AND WHETHER THEY WILL BE IN THE FORM OF RAIN OR SNOW. WITH
THE MORE ZONAL PATTERN FAVORING THE FASTER GFS BUT RECENT
VERIFICATION FAVORING THE ECMWF WILL USE THE ALLBLEND AVERAGE FOR
CHANCE POPS ACROSS THE AREA AND GO WITH RAIN AND SNOW UNTIL BETTER
AGREEMENT EMERGES. TUESDAY NIGHT LOOKS DRY. MODELS SHOW THE NEXT
SYSTEM ARRIVING IN THE WEDNESDAY NIGHT TO THURSDAY NIGHT TIME
SPAN BRINGING ANOTHER QUICK SHOT OF COLD AIR AND POSSIBLE PRECIP
CHANCES...BUT THOSE ARRIVE AFTER THE FORECAST PERIOD.
&&
.AVIATION /DISCUSSION FOR THE 121500Z KIND TAF UPDATE/...
RADAR TRENDS SUGGEST THE ARRIVAL OF THE SNOW AT KIND MAY BE SOONER
THAN WHAT IS CURRENTLY IN THE FORECAST. WILL NUDGE UP THE ARRIVAL OF
THE SNOW AND ASSOCIATED IFR VISIBILITY RESTRICTIONS TO AROUND
121600Z. UPSTREAM OBSERVATIONS ACROSS ILLINOIS SUGGEST POTENTIAL FOR
A PERIOD OF LIFR VISIBILITY RESTRICTIONS LATER THIS AFTERNOON. MAY
NEED TO ADD THIS IN LATER UPDATES. PREVIOUS DISCUSSION FOLLOWS.
SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY
MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW
HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND
SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF
ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE
VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE
INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF
LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL
THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS
INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND
THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL.
LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW
SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A
HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE
WIDESPREAD LOW MVFR.
WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD
SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD
START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED
SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30
KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE
WESTERLY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST FRIDAY FOR INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...JH
NEAR TERM...PUMA
SHORT TERM...JH
LONG TERM....CP
AVIATION...CP/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
938 AM EST THU JAN 12 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A STRONG COLD FRONT WILL SWEEP ACROSS INDIANA THIS MORNING. THEN A
STRONG UPPER LOW WILL MOVE ACROSS SOUTHERN INDIANA THIS EVENING AND
TO THE EASTERN GREAT LAKES FRIDAY. AN UPPER LEVEL DISTURBANCE WILL
TRACK ACROSS THE MID MISSISSIPPI AND OHIO VALLEYS LATE SATURDAY.
IN THE EXTENDED THE UPPER FLOW BECOMES MORE ZONAL EARLY NEXT WEEK
CAUSING TEMPERATURES TO MODERATE. AN UPPER DISTURBANCE WILL AFFECT
OUR WEATHER BY LATE MONDAY AND A COLD FRONT WILL MOVE ACROSS OUR
REGION TUESDAY. HIGH PRESSURE BEHIND THIS FRONT WILL BUILD ACROSS
OUR REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
MAIN FOCUS WILL BE WORSENING WEATHER CONDITIONS LATER TODAY AND
WHETHER TO MAKE ANY CHANGES TO PREVIOUS PACKAGE. THE RAIN FROM
YESTERDAYS SYSTEM HAD MOVED OUT AND SNOW WAS BEGINNING TO SPREAD
INTO INTO WESTERN ILLINOIS. THE RAPID REFRESH BRINGS SNOW INTO
WESTERN INDIANA BY 15Z AND MOST OTHER AREAS MIDDAY OR LATER. MOST
OF THE SIGNIFICANT ACCUMULATIONS WILL BE THIS AFTERNOON AND WINDS
WILL BE INCREASING THEN TOO. WILL BEGIN WINTER WEATHER ADVISORY
ACROSS OUR FORECAST AREA AROUND NOON AND CONTINUE IT TO 1 PM
TOMORROW.
THE NAM AND CANADIAN MODELS INDICATE SLIGHTLY LOWER PRECIP AMOUNTS
ACROSS OUR SOUTHEAST. A LITTLE MORE THAN A HALF INCH. ON THE OTHER
HAND...THE EUROPEAN AND GFS MODELS ARE LITTLE CHANGED FROM PREVIOUS
RUNS. WILL SLOWER AMOUNTS SLIGHTLY ACROSS OUR SOUTHEAST HALF
TODAY...BUT STILL ENOUGH TO SUPPORT THE WINTER WEATHER ADVISORY AS
WINDS INCREASE CAUSING BLOWING AND DRIFTING SNOW BY TONIGHT.
AS FAR AS TEMPERATURES...WENT WITH A BLEND OF SREF 2 METER
TEMPERATURES AND MAV/MET HOURLY NUMBERS. TEMPERATURES WILL FALL
INTO THE MID 20S MOST AREAS BY THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MODELS ARE INDICATING THAT BEST TIME FRAME FOR SNOW ACCUMULATION
WILL BE FRI 00-06Z TONIGHT. BEST QVECTOR CONVERGENCE AND
FRONTOGENETIC BANDING WILL BE ACROSS THE NORTHERN COUNTIES OF
FORECAST AREA. TOTAL ACCUMULATIONS BY FRIDAY MORNING WILL RANGE FROM
1 TO 2 INCHES SOUTHERN SECTIONS...2 TO 3 INCHES ALONG THE INTERSTATE
70 CORRIDOR TO AROUND 3 TO 5 INCHES NEAR KOKOMO.
ISENTROPIC LIFT WILL ALSO BE BEST OVER THE NORTHERN COUNTIES...WITH
MOISTURE LACKING OVER THE SOUTHERN COUNTIES. SATURATION IN THE
DENDRITIC GROWTH ZONE WAS NOT OVERLY IMPRESSIVE EITHER...WHICH WILL
LIMIT SNOWFALL.
WRAPAROUND MOISTURE WILL RESULT IN SNOW SHOWERS ACROSS THE
NORTHEAST QUADRANT THROUGH FRIDAY MORNING. HOWEVER...THE MAIN
THREAT ON FRIDAY WILL BE THE STRONG WEST WINDS WITH SUSTAINED
SPEEDS OF 15 TO 25 MPH AND GUSTS TO 30 MPH. THIS WILL CREATE
BLOWING AND DRIFTING SNOW AND REDUCED VISIBILITIES. AS A
RESULT...CARRIED THE WINTER WEATHER ADVISORY TO FRI 18Z.
COLD ARCTIC AIR WILL SIT ACROSS CENTRAL INDIANA IN WAKE OF THIS
SYSTEM INTO THE WEEKEND. MODELS HAVE TRENDED A LITTLE COLDER FRIDAY
THROUGH SATURDAY AND WITH A COUPLE OF INCHES OF SNOW COVER...SEE NO
REASON NOT TO FOLLOW THIS TREND.
WEAK AREA OF HIGH PRESSURE WILL MOVE ACROSS OUR REGION LATE FRIDAY
NIGHT AND EARLY SATURDAY. THEN MODELS BRING A FAST MOVING CLIPPER
INTO THE OHIO VALLEY BY LATE SATURDAY. WESTERN AND SOUTH CENTRAL
SECTIONS COULD SEE UP TO AN INCH BY SATURDAY EVENING BEFORE THIS
SYSTEM MOVES OFF QUICKLY TO THE EAST SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
UPPER RIDGING BUILDS IN AND MOVES ACROSS THE AREA SUNDAY AND SUNDAY
NIGHT BRINGING IN SOME DRY AIR AND SCATTERING OUT SKY COVER. DURING
THE DAY MONDAY THE AREA WILL BE ON THE BACK SIDE OF THE RIDGE WITH
AN UPPER TROUGH TO THE EAST AND A COLD FRONT FIRMING UP OVER THE
PLAINS. THIS WILL ALLOW WARM ADVECTION TO RAMP UP AND ISENTROPIC
LIFT TO ENTER THE AREA BRINGING SMALL CHANCES FOR RAIN ON MONDAY. BY
MONDAY NIGHT THE LIFT REALLY INCREASES AHEAD OF THE COLD FRONT AND
MOISTURE SHOULD BE STREAMING UP FROM THE GULF ON A 50+ KT LOW LEVEL
JET. THOUGHT THE LIKELY POPS FROM THE ALLBLEND MATCHED UP WITH THIS
WELL. GFS AND ECMWF HAVE A BIT OF A DIFFERENCE IN THE TIMING OF THE
COLD FRONTAL PASSAGE TUESDAY WHICH COULD MAKE A DIFFERENCE IN HIGH
TEMPERATURES FOR THE DAY AS WELL AS HOW LONG PRECIPITATION CHANCES
WILL LAST AND WHETHER THEY WILL BE IN THE FORM OF RAIN OR SNOW. WITH
THE MORE ZONAL PATTERN FAVORING THE FASTER GFS BUT RECENT
VERIFICATION FAVORING THE ECMWF WILL USE THE ALLBLEND AVERAGE FOR
CHANCE POPS ACROSS THE AREA AND GO WITH RAIN AND SNOW UNTIL BETTER
AGREEMENT EMERGES. TUESDAY NIGHT LOOKS DRY. MODELS SHOW THE NEXT
SYSTEM ARRIVING IN THE WEDNESDAY NIGHT TO THURSDAY NIGHT TIME
SPAN BRINGING ANOTHER QUICK SHOT OF COLD AIR AND POSSIBLE PRECIP
CHANCES...BUT THOSE ARRIVE AFTER THE FORECAST PERIOD.
&&
.AVIATION /DISCUSSION FOR THE 121500Z KIND TAF UPDATE/...
RADAR TRENDS SUGGEST THE ARRIVAL OF THE SNOW AT KIND MAY BE SOONER
THAN WHAT IS CURRENTLY IN THE FORECAST. WILL NUDGE UP THE ARRIVAL OF
THE SNOW AND ASSOCIATED IFR VISIBILITY RESTRICTIONS TO AROUND
121600Z. UPSTREAM OBSERVATIONS ACROSS ILLINOIS SUGGEST POTENTIAL FOR
A PERIOD OF LIFR VISIBILITY RESTRICTIONS LATER THIS AFTERNOON. MAY
NEED TO ADD THIS IN LATER UPDATES. PREVIOUS DISCUSSION FOLLOWS.
SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY
MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW
HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND
SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF
ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE
VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE
INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF
LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL
THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS
INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND
THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL.
LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW
SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A
HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE
WIDESPREAD LOW MVFR.
WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD
SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD
START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED
SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30
KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE
WESTERLY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON TODAY TO 1 PM EST FRIDAY FOR
INZ021-028>031-035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM....CP
AVIATION...CP/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
601 AM EST THU JAN 12 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A STRONG COLD FRONT WILL SWEEP ACROSS INDIANA THIS MORNING. THEN A
STRONG UPPER LOW WILL MOVE ACROSS SOUTHERN INDIANA THIS EVENING AND
TO THE EASTERN GREAT LAKES FRIDAY. AN UPPER LEVEL DISTURBANCE WILL
TRACK ACROSS THE MID MISSISSIPPI AND OHIO VALLEYS LATE SATURDAY.
IN THE EXTENDED THE UPPER FLOW BECOMES MORE ZONAL EARLY NEXT WEEK
CAUSING TEMPERATURES TO MODERATE. AN UPPER DISTURBANCE WILL AFFECT
OUR WEATHER BY LATE MONDAY AND A COLD FRONT WILL MOVE ACROSS OUR
REGION TUESDAY. HIGH PRESSURE BEHIND THIS FRONT WILL BUILD ACROSS
OUR REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
MAIN FOCUS WILL BE WORSENING WEATHER CONDITIONS LATER TODAY AND
WHETHER TO MAKE ANY CHANGES TO PREVIOUS PACKAGE. THE RAIN FROM
YESTERDAYS SYSTEM HAD MOVED OUT AND SNOW WAS BEGINNING TO SPREAD
INTO INTO WESTERN ILLINOIS. THE RAPID REFRESH BRINGS SNOW INTO
WESTERN INDIANA BY 15Z AND MOST OTHER AREAS MIDDAY OR LATER. MOST
OF THE SIGNIFICANT ACCUMULATIONS WILL BE THIS AFTERNOON AND WINDS
WILL BE INCREASING THEN TOO. WILL BEGIN WINTER WEATHER ADVISORY
ACROSS OUR FORECAST AREA AROUND NOON AND CONTINUE IT TO 1 PM
TOMORROW.
THE NAM AND CANADIAN MODELS INDICATE SLIGHTLY LOWER PRECIP AMOUNTS
ACROSS OUR SOUTHEAST. A LITTLE MORE THAN A HALF INCH. ON THE OTHER
HAND...THE EUROPEAN AND GFS MODELS ARE LITTLE CHANGED FROM PREVIOUS
RUNS. WILL SLOWER AMOUNTS SLIGHTLY ACROSS OUR SOUTHEAST HALF
TODAY...BUT STILL ENOUGH TO SUPPORT THE WINTER WEATHER ADVISORY AS
WINDS INCREASE CAUSING BLOWING AND DRIFTING SNOW BY TONIGHT.
AS FAR AS TEMPERATURES...WENT WITH A BLEND OF SREF 2 METER
TEMPERATURES AND MAV/MET HOURLY NUMBERS. TEMPERATURES WILL FALL
INTO THE MID 20S MOST AREAS BY THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MODELS ARE INDICATING THAT BEST TIME FRAME FOR SNOW ACCUMULATION
WILL BE FRI 00-06Z TONIGHT. BEST QVECTOR CONVERGENCE AND
FRONTOGENETIC BANDING WILL BE ACROSS THE NORTHERN COUNTIES OF
FORECAST AREA. TOTAL ACCUMULATIONS BY FRIDAY MORNING WILL RANGE FROM
1 TO 2 INCHES SOUTHERN SECTIONS...2 TO 3 INCHES ALONG THE INTERSTATE
70 CORRIDOR TO AROUND 3 TO 5 INCHES NEAR KOKOMO.
ISENTROPIC LIFT WILL ALSO BE BEST OVER THE NORTHERN COUNTIES...WITH
MOISTURE LACKING OVER THE SOUTHERN COUNTIES. SATURATION IN THE
DENDRITIC GROWTH ZONE WAS NOT OVERLY IMPRESSIVE EITHER...WHICH WILL
LIMIT SNOWFALL.
WRAPAROUND MOISTURE WILL RESULT IN SNOW SHOWERS ACROSS THE
NORTHEAST QUADRANT THROUGH FRIDAY MORNING. HOWEVER...THE MAIN
THREAT ON FRIDAY WILL BE THE STRONG WEST WINDS WITH SUSTAINED
SPEEDS OF 15 TO 25 MPH AND GUSTS TO 30 MPH. THIS WILL CREATE
BLOWING AND DRIFTING SNOW AND REDUCED VISIBILITIES. AS A
RESULT...CARRIED THE WINTER WEATHER ADVISORY TO FRI 18Z.
COLD ARCTIC AIR WILL SIT ACROSS CENTRAL INDIANA IN WAKE OF THIS
SYSTEM INTO THE WEEKEND. MODELS HAVE TRENDED A LITTLE COLDER FRIDAY
THROUGH SATURDAY AND WITH A COUPLE OF INCHES OF SNOW COVER...SEE NO
REASON NOT TO FOLLOW THIS TREND.
WEAK AREA OF HIGH PRESSURE WILL MOVE ACROSS OUR REGION LATE FRIDAY
NIGHT AND EARLY SATURDAY. THEN MODELS BRING A FAST MOVING CLIPPER
INTO THE OHIO VALLEY BY LATE SATURDAY. WESTERN AND SOUTH CENTRAL
SECTIONS COULD SEE UP TO AN INCH BY SATURDAY EVENING BEFORE THIS
SYSTEM MOVES OFF QUICKLY TO THE EAST SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
UPPER RIDGING BUILDS IN AND MOVES ACROSS THE AREA SUNDAY AND SUNDAY
NIGHT BRINGING IN SOME DRY AIR AND SCATTERING OUT SKY COVER. DURING
THE DAY MONDAY THE AREA WILL BE ON THE BACK SIDE OF THE RIDGE WITH
AN UPPER TROUGH TO THE EAST AND A COLD FRONT FIRMING UP OVER THE
PLAINS. THIS WILL ALLOW WARM ADVECTION TO RAMP UP AND ISENTROPIC
LIFT TO ENTER THE AREA BRINGING SMALL CHANCES FOR RAIN ON MONDAY. BY
MONDAY NIGHT THE LIFT REALLY INCREASES AHEAD OF THE COLD FRONT AND
MOISTURE SHOULD BE STREAMING UP FROM THE GULF ON A 50+ KT LOW LEVEL
JET. THOUGHT THE LIKELY POPS FROM THE ALLBLEND MATCHED UP WITH THIS
WELL. GFS AND ECMWF HAVE A BIT OF A DIFFERENCE IN THE TIMING OF THE
COLD FRONTAL PASSAGE TUESDAY WHICH COULD MAKE A DIFFERENCE IN HIGH
TEMPERATURES FOR THE DAY AS WELL AS HOW LONG PRECIPITATION CHANCES
WILL LAST AND WHETHER THEY WILL BE IN THE FORM OF RAIN OR SNOW. WITH
THE MORE ZONAL PATTERN FAVORING THE FASTER GFS BUT RECENT
VERIFICATION FAVORING THE ECMWF WILL USE THE ALLBLEND AVERAGE FOR
CHANCE POPS ACROSS THE AREA AND GO WITH RAIN AND SNOW UNTIL BETTER
AGREEMENT EMERGES. TUESDAY NIGHT LOOKS DRY. MODELS SHOW THE NEXT
SYSTEM ARRIVING IN THE WEDNESDAY NIGHT TO THURSDAY NIGHT TIME
SPAN BRINGING ANOTHER QUICK SHOT OF COLD AIR AND POSSIBLE PRECIP
CHANCES...BUT THOSE ARRIVE AFTER THE FORECAST PERIOD.
&&
.AVIATION /DISCUSSION FOR 121200Z TAF ISSUANCE/...
SITES WILL START OFF LOW MVFR OR IFR DUE TO CEILINGS WITH MAINLY
MVFR VISIBILITIES. THESE CONDITIONS SHOULD CONTINUE FOR THE NEXT FEW
HOURS UNTIL SNOW SHOWERS BEGIN TO ARRIVE IN THE WEST AROUND 15Z AND
SPREAD NORTH AND EAST IMPACTING ALL THE SITES BY 18Z. USED TIMING OF
ARRIVAL FROM RUC AND HRRR...WHICH WERE AN HOUR OR SO FASTER THAN THE
VSREFS. WITH SOME ECHOES LOOKING PRETTY STRONG IN THE HRRR FOR THE
INITIAL WAVE OF SNOW THAT MOVES THROUGH DID INCLUDE A TEMPO GROUP OF
LOWER VISIBILITIES. USED THE VSREFS TO COME UP WITH 1 1/2SM FOR ALL
THE SITES FOR A COUPLE OF HOURS AFTER SNOW BEGINS. AFTER THIS
INITIAL SHOT SNOW WILL BE MORE SHOWERY AND ON AND OFF IN NATURE AND
THINK IFR CEILINGS WITH MVFR VISIBILITIES SHOULD COVER THIS WELL.
LATER TONIGHT AROUND 0Z COULD SEE ANOTHER BOUT OF HEAVIER SNOW
SHOWERS AGAIN WITH WIDESPREAD VISIBILITIES AROUND A MILE AND A
HALF...BUT THESE CONDITIONS SHOULD IMPROVE SOMEWHAT AFTER 6Z TO MORE
WIDESPREAD LOW MVFR.
WINDS WILL BE AN ISSUE TODAY AND THEIR BLOWING OF THE SNOW COULD
SERVE TO DECREASE VISIBILITIES AS WELL. GUSTS IN THE TEENS COULD
START WITHIN THE NEXT COUPLE OF HOURS AND WILL ONLY SEE SUSTAINED
SPEEDS AND GUSTS INCREASE THROUGHOUT THE DAY WITH GUSTS AROUND 30
KTS BY 0Z AND LASTING THROUGHOUT THE OVERNIGHT. WINDS WILL MAINLY BE
WESTERLY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON TODAY TO 1 PM EST FRIDAY FOR
INZ021-028>031-035>049-051>057-060>065-067>072.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM....CP
AVIATION...CP
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
538 PM CST FRI JAN 13 2012
.AVIATION...
MVFR CONDITIONS WILL CONTINUE THROUGH EARLY EVENING WITH
INTERMITTENT LIGHT SNOW. THE -SN IS EXPECTED TO COMPLETELY
DISSIPATE BY 03Z. VFR WX WILL THEN BE SEEN AS HIGH PRESSURE MOVES
ACROSS EASTERN IOWA AND ILLINOIS OVERNIGHT. THE NEXT SYSTEM APPROACHES FROM
THE NORTHERN PLAINS SATURDAY MORNING...WITH -SN EXPECTED TO DEVELOP
BY MID TO LATE MORNING AT KCID/KBRL. 12Z- 18Z/14 MVFR CONDITIONS
COULD DEVELOP AGAIN AT ALL TAF SITES AS -SN BECOMES MORE
WIDESPREAD. ..ERVIN..
&&
.PREV DISCUSSION... /ISSUED 327 PM CST FRI JAN 13 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS AN EXTRATROPICAL CYCLONE IN SOUTHEAST CANADA
WITH NUMEROUS TROFS FROM THE TENNESSEE VALLEY BACK INTO THE UPPER
MIDWEST. RADAR TRENDS THROUGH MID AFTERNOON CONTINUE TO SHOW PLENTY
OF FLURRIES AND LIGHT SNOW OVER THE MID MISSISSIPPI VALLEY. CLEARING
UNDER THE CYCLONIC FLOW WAS MAKING SLOW BUT STEADY PROGRESS EASTWARD.
18Z SFC ANALYSIS HAS A COLD FRONT FROM THE EASTERN GREAT LAKES BACK
INTO NORTHEAST ILLINOIS WITH A HIGH PRESSURE RIDGE FROM MINNESOTA
INTO EASTERN TEXAS. A CHINOOK WARM FRONT WAS OVER THE EASTERN PARTS
OF THE DAKOTAS AND NEBRASKA. A WARM FRONT ASSOCIATED WITH THE NEXT
CLIPPER SYSTEM WAS MOVING OUT OF THE NORTHERN ROCKIES. DEW POINTS
UNDER THE HIGH PRESSURE RIDGE WERE IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO. OTHERWISE DEW POINTS WERE IN THE TEENS AND 20S ACROSS
THE MIDWEST AND PLAINS.
SHORT TERM...TONIGHT AND SATURDAY...
LIGHT SNOW WILL CONTINUE THROUGH LATE AFTERNOON BUT WILL TAPER TO
FLURRIES ONCE SUNSET OCCURS. RUC TRENDS CONTINUE TO SHOW WEAK F
VECTOR CONVERGENCE AND WEAK FRONTOGENETICAL FORCING WILL REMAIN
ACROSS THE AREA INTO THE EARLY EVENING. THAT COMBINED WITH THE
SHALLOW ARCTIC AIR MASS AND A VORT MAX MOVING THROUGH THE CWFA WILL
ALLOW FLURRIES TO PERSIST THROUGH MID EVENING.
CLEARING WILL OCCUR FROM WEST TO EAST DURING THE EVENING AND
OVERNIGHT HOURS. TEMPERATURES SHOULD DROP QUICKLY ONCE CLEARING
OCCURS DUE TO THE SNOW COVER AND LIGHT WINDS. AFTER MIDNIGHT...WAA
CLOUDS FROM THE APPROACHING CLIPPER SYSTEM WILL MOVE INTO THE AREA
AND LIKELY ALLOW TEMPERATURES TO BOTTOM OUT AND SLOWLY RISE.
AFTER 3 AM...ALL MODELS SHOW F VECTOR CONVERGENCE DEVELOPING AGAIN
WITH COLLAPSING CONDENSATION PRESSURE DEFICITS ALONG WITH AN
INCREASE IN FRONTOGENETICAL FORCING. MOISTURE WITH THIS CLIPPER
SYSTEM IS LIMITED BUT FLURRIES AND LIGHT SNOW SHOULD BREAK OUT PRIOR
TO DAWN GENERALLY WEST OF A KIIB TO KPPQ LINE. SCHC/CHC POPS WERE
DONE DUE TO THE LIMITED MOISTURE BUT MAY NEED TO BE RAISED IN THE
EXTREME WEST AND SOUTHWEST PARTS OF THE CWFA.
THE WAA PRECIPITATION WING OF THE CLIPPER SYSTEM WILL MOVE ACROSS
THE WESTERN HALF OR TWO THIRDS OF THE CWFA SATURDAY MORNING.
CONDENSATION PRESSURE DEFICITS REMAIN LOW AND THERE IS F VECTOR
CONVERGENCE WITH SOME FORCING. DURING THE AFTERNOON THE COLD
CONVEYOR BELT PRECIPITATION FROM THE CLIPPER SYSTEM WILL OVERSPREAD
THE ENTIRE AREA BEFORE ENDING FROM THE WEST LATE IN THE AFTERNOON.
AS FOR AMOUNTS...A DUSTING OF ACCUMULATION IS POSSIBLE PRIOR TO
SUNRISE IN THE FAR WEST/SOUTHWEST PARTS OF THE CWFA. ACCUMULATIONS
DURING THE DAY SATURDAY SHOULD RANGE FROM A DUSTING TO ONE HALF
INCH. IT IS CONCEIVABLE THAT ACCUMULATIONS APPROACHING AN INCH MAY
OCCUR OVER THE SOUTHWEST THIRD TO HALF OF THE CWFA. ..08..
LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
ACTIVE/UNSETTLED PATTERN TO PERSIST THROUGH THE PERIOD WITH MANY FCST
CHALLENGES. MAIN STORM SYSTEM THAT BEARS CONSIDERABLE WATCHING IS IN
MON-TUE TIME-FRAME. THIS STORM LOOKS TO BRING WINTRY MIX OF PCPN WITH
POTENTIAL FOR HEADLINES.
SAT NGT... SOME RESIDUAL WEAK LIFT LINGERS INTO THE EVE ACROSS THE NORTH
AS CLIPPER DEPARTS AND WARM FRONT PUSHES THROUGH. NAM AND GFS
BUFR SOUNDINGS SHOW LOSS OF ICE INTRODUCTION WHICH WOULD SUPPORT DRIZZLE
OR FREEZING DRIZZLE. CONCERNS THOUGH THESE MODELS MAY BE OVERDONE WITH
EXTENT OF LOW LEVEL MOISTURE ... A TYPICAL BIAS ESPECIALLY WITH
NAM... ESPECIALLY GIVEN NO SNOW MELT. GIVEN UNCERTAINTIES AND WITH
ANY PCPN JUST TRACE AMOUNTS HAVE LEFT OUT ANY MENTION ATTIM. MAY SEE
TEMPS STEADY OR RISING OVRNGT ESPECIALLY SOUTH WITH ONSET OF LOW LEVEL
WARM ADVECTION.
SUN-SUN NGT... NEXT ARCTIC FRONT TO EMERGE INTO THE PLAINS AND EXPECTED
TO PUSH THROUGH IA AND POSSIBLY BISECTING 12Z MON PER NAM/GFS. HI-RES
ECMWF SLOWER BUT 12Z RUN IS SLIGHTLY FASTER AND MAY BE TRENDING TOWARD
NAM/GFS. DEEPER MOISTURE RETURNS LATE FOR POSSIBLY SOME VERY LIGHT RAIN
OR DRIZZLE AFTER MIDNIGHT... OR VERY LIGHT FREEZING RAIN/DRIZZLE IN SOME
AREAS DEPENDING ON SFC TEMPS WITH NW CWA MOST SUSCEPTIBLE IT APPEARS
ATTIM BUT THIS DEPENDENT ON FRONTAL TIMING. MOST IF NOT ALL OF
AREA SHOULD GET ABOVE FREEZING WITH 40S WIDESPREAD ACROSS THE SW CWA ON
GUSTY SOUTHERLY WINDS.
MON-TUE... STRONG BAROCLINICITY AND COUPLED JET STRUCTURE SUPPORT
CYCLOGENESIS ALONG ARCTIC FRONT... WITH CONSIDERABLE MODEL SPREAD ON
MAGNITUDE/TRACK/TIMING... AND GIVEN HIGHLY DYNAMICAL ENVIRONMENT EXPECT
CONTINUED CHANGES IN MODELS NEXT DAY OR TWO. GFS AND HI-RES ECMWF HAVE
TRENDED DEEPER AND SLOWER... AND MAY CONTINUE TO SEE THIS TREND. BOTTOM
LINE IS MOISTURE AND FORCING SUPPORTS MODERATE QPF EVENT NOT TOO
DISSIMILAR FROM THIS MOST RECENT EVENT. DEPENDING ON FRONT AND SFC LOW
LOCATIONS PCPN TYPES COULD VARY OR TRANSITION FROM RAIN TO FREEZING
RAIN...SLEET AND SNOW ACROSS CWA. THEREFORE... WITH THE WINTRY MIXTURE
THIS SYSTEM WILL BEAR CONSIDERABLE WATCHING IN THE DAYS AHEAD. POPS ARE
IN MOD/HIGH CHC CATEGORY FOR NOW GIVEN UNCERTAINTY WITH TRACK. IN
ADDITION MAY SEE FOG MON WITH AREAS OF DENSE FOG AHEAD OF SFC LOW WITHIN
LOW LEVEL MOISTURE CONVERGENCE.
WED-FRI... MUCH COLDER WITH ANOTHER ARCTIC FRONT SUGGESTED TO ARRIVE
WED THAT MAY NEED POPS IN LATER FCSTS. FOR NOW THOUGH HAVE CHC POPS
THU-FRI AS ENERGY RIPPLES ALONG LOW-MID LEVEL BAROCLINIC ZONE. WINTER HAS
FINALLY ARRIVED. ..05..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
339 PM CST THU JAN 12 2012
.SYNOPSIS...
12Z UA ANALYSIS HAD AN 850MB LOW ALONG THE IA/WI BORDER WITH
ANOTHER IN SOUTHEAST LOWER MICHIGAN. A TROF EXTENDED SOUTH FROM
THE IA/WI LOW INTO SOUTHEAST MISSOURI. RADAR TRENDS THROUGH EARLY
AFTERNOON SHOW AN UPPER LEVEL FEATURE THAT IS PIVOTING A
DEFORMATION ZONE ACROSS EASTERN IOWA AND NORTHERN ILLINOIS.
18Z SFC ANALYSIS HAS AN OCCLUDED LOW BETWEEN KGRR AND KAZO AND
ANOTHER ON THE SOUTHERN EDGE OF LAKE HURON. THE POLAR FRONT
EXTENDED SOUTH FROM THE OCCLUDED LOW INTO CENTRAL ALABAMA. SEVERAL
WEAK TROFS RAN FROM SOUTHERN LAKE MICHIGAN INTO MISSOURI BACK UP
INTO SOUTHERN WISCONSIN AND IOWA. DEW POINTS WERE IN THE TEENS AND
20S FROM THE WESTERN GREAT LAKES AND LOWER MISSISSIPPI VALLEY TO
THE SINGLE DIGITS ABOVE AND BELOW ZERO ACROSS THE PLAINS.
&&
.SHORT TERM...TONIGHT...
RADAR AND WATER VAPOR ARE QUITE INTERESTING. A VORT MAX IS
ROTATING AROUND THE UPPER LOW IN SOUTHERN ILLINOIS WHICH IS
HELPING TO PIVOT THE DEFORMATION ZONE ACROSS THE CWFA. THE END
POINT OF THE PIVOT IS SLOWLY DRIFTING TO THE EAST SOUTHEAST AS THE
UPPER LOW MOVES INTO THE OHIO VALLEY PER RUC TRENDS. THUS LIGHT TO
MODERATE SNOW WITH BURSTS OF HEAVY SNOW WILL CONTINUE THROUGH 6 PM.
THE RUC SHOWS ANOTHER VORT MAX ROTATING FROM NORTHEAST ILLINOIS
BACK INTO EASTERN IOWA DURING THE EARLY EVENING. THIS FEATURE
SHOULD ALLOW THE SNOW TO MAINTAIN ITSELF THROUGH 9 PM. AFTER 9 PM
THE FORCING OVER THE WESTERN THIRD OF THE CWFA WEAKENS RAPIDLY SO
THE SNOW THERE SHOULD QUICKLY TAPER TO FLURRIES.
THE RUC TRENDS BLEND IN NICELY WITH THE WRF/GFS TRENDS INDICATING
THE OVERALL FORCING WEAKENING RAPIDLY AFTER MIDNIGHT ACROSS THE
EASTERN TWO THIRDS OF THE CWFA. THUS SNOW WILL TAPER TO FLURRIES
ACROSS THE REMAINDER OF THE CWFA AFTER MIDNIGHT WITH ALL BUT THE
FAR EASTERN PARTS OF THE CWFA SEEING THE FLURRIES END PRIOR TO
SUNRISE.
THE CURRENT HEADLINES WILL REMAIN AS IS FOR NOW. IF THE TRENDS
FROM THE RUC AND OTHER MODELS ARE CORRECT...THE POSSIBILITY DOES
EXIST THAT THE HEADLINES MAY BE CANCELLED EARLIER THAN THE CURRENT
END TIMES.
NOW FOR AMOUNTS. ADDITIONAL SNOWFALL THIS EVENING SHOULD RANGE
FROM A DUSTING IN THE FAR WESTERN PARTS OF THE CWFA TO JUST OVER
AN INCH IN THE EASTERN THIRD OF THE CWFA. MOST OF THIS ADDITIONAL
SNOWFALL WILL OCCUR BETWEEN 6 AND 8 PM. AFTER MIDNIGHT...AN
ADDITIONAL DUSTING MAY OCCUR IN THE EASTERN THIRD OF THE CWFA
WHERE LIGHT SNOW WILL LINGER THE LONGEST.
SO...STORM TOTALS SHOULD BE A GENERAL 3 TO 6 INCHES ACROSS THE
AREA. AN AREA 20 MILES EITHER SIDE OF A LINE CENTERED FROM CEDAR
RAPIDS TO ROUGHLY STERLING SHOULD SEE 5 TO 7 INCHES WITH LOCALLY
HIGHER AMOUNTS.
..08..
.LONG TERM...FRIDAY THROUGH NEXT THURSDAY...
ACTIVE PATTERN TO PREVAIL THROUGH THE PERIOD.
FRI-FRI NGT...ADDITIONAL ENERGY DIVING DOWN BACKSIDE OF DEPARTING
SYSTEM WILL KEEP CLOUDS AND POSSIBLY FEW FLURRIES AROUND
FOR A TIME FRI AM. THEN EXPECT SOME DECREASE IN CLOUDS FRI AFTN
WITH SUBSIDENCE. BRISK NW WINDS CONTINUE AND WITH CLOUDS SLOW TO
DECREASE AND FRESH SNOW HAVE SIDED AT OR BELOW COLD SIDE OF GUIDANCE
FOR HIGHS. NEXT CLIPPER SYSTEM WHICH SEEN ON WATER VAPOR JUST
COMING INTO BC APPEARS TO BE A LITTLE STRONGER THAT PROGGED. THIS
ENERGY TO HEAD SE FRI NGT AND WILL SEE INCREASE IN CLOUDS WITH WARM
ADVECTION WING WITH CHC OF -SN/--SN LATE PORTIONS OF W/NW. LIGHT
WINDS AND PARTIAL CLEARING FOR TIME FRI EVE SHOULD AID IN QUICK DROP
TO NEAR OR BELOW GUIDANCE MINS BEFORE TEMPS STEADY OR RISE WITH
CLOUDS AND LLVL WARM ADVECTION OVRNGT.
SAT-SAT NGT...CLIPPER SYSTEM TO PASS DURING DAY WITH STILL PLENTY
OF SPREAD ON TRACK AND STRENGTH. ENHANCED BAROCLINICITY FROM
EVOLVING SNOW FIELD MAY PLAY ROLE... AND GIVEN THIS AND WHAT LOOKS
LIKE STRONGER WAVE WONDER IF TRACK AND POPS MAY NEED TO BE
ADJUSTED SWWD. LIMITED MOISTURE AND SO COULD END UP MOSTLY FLURRIES
WITH AREAS OF -SN WITH ANY ACCUMS MINOR AT OR BELOW 1 INCH. AT LEAST
PARTIAL CLEARING SAT NGT IN WAKE WITH LIGHT WINDS AND HAVE LOWERED
MINS TO BELOW GUIDANCE... BUT RETURN FLOW KICKS IN LATE THAT MAY SEE
TEMPS CLIMB OVRNGT.
SUN-SUN NGT... DRY WITH MODERATING TEMPS AS WARM ADVECTION STRENGTHENS
ON GUSTY SLY WINDS... WITH HEIGHTS BUILDING ALOFT. FRONT MOVES INTO
IA SUN NGT BUT SUGGESTION OF PCPN STAYING SOUTH OF CWA ACROSS PORTIONS
OF MO SWD WITHIN DEEPER LLVL MOISTURE RETURN.
MON-TUE... NEXT FRONT TO PASS WITH ENERGY AND BAROCLINICITY FAVORING
SFC LOW DEVELOPMENT ALONG FRONT PASSING NEAR REGION THAT MAY
REQUIRE POPS BEING RAISED. THERMAL PARAMETERS SUPPORT MAINLY RAIN MON
BUT AS FRONT SAGS ACROSS CWA MON NGT AND COLDER AIR MOVES IN COULD
SEE MIX THEN CHANGE TO SNOW WITH ANY RESIDUAL MOISTURE ON BACKSIDE
LINGERING INTO TUE. ANY SNOW ACCUMS WOULD APPEAR TO BE LIGHT ATTIM.
WED-THU...MUCH COLDER WITH CHC OF SNOW LATE PD WITH NEXT BOUT OF ENERGY.
..05..
&&
.AVIATION...
IFR TO LIFR CONDITIONS WITH SNOW WILL CONTINUE THROUGH 02Z/13. AFT
02Z/13 CONDITIONS WILL SLOWLY IMPROVE TO MVFR. SNOW INTENSITY WILL
DECREASE RAPIDLY AFT 02Z/13 AND TAPER TO FLURRIES BEFORE ENDING.
VSBYS TO BECOME VFR AFT 06Z/13 WITH MVFR CIGS.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER STORM WARNING UNTIL 3 AM CST FRIDAY FOR CLINTON-JACKSON-
SCOTT.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BENTON-
BUCHANAN-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-KEOKUK-
LEE-LOUISA-MUSCATINE-VAN BUREN-WASHINGTON.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR CEDAR-
DELAWARE-DUBUQUE-JONES-LINN.
IL...WINTER STORM WARNING UNTIL 3 AM CST FRIDAY FOR CARROLL-JO
DAVIESS-ROCK ISLAND-STEPHENSON-WHITESIDE.
WINTER WEATHER ADVISORY UNTIL 3 AM CST FRIDAY FOR BUREAU-HANCOCK-
HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-WARREN.
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK-
SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1147 AM CST THU JAN 12 2012
.UPDATE...
BASED ON MORNING UA AND CURRENT TRENDS FROM THE RUC AND RADAR...A
PORTION OF THE WINTER WEATHER ADVISORY HAS BEEN UPGRADED TO A
WINTER STORM WARNING. WE WILL EASILY ACHIEVE A VERY HIGH END
ADVISORY. HOWEVER...THE LACK OF SNOW SO FAR THIS SEASON COMBINED
WITH THE WIND HAS RESULTED IN A LOWERING OF THE NORMAL THRESHOLDS.
RUC TRENDS SHOW THE DEFORMATION ZONE SETTING UP OVER ROUGHLY THE
NORTHERN CWFA AND WILL PIVOT TO THE NORTHEAST DURING THE AFTERNOON
HOURS. THE WAA TOOL SUGGESTS THE STRONGEST FORCING ON THE WESTERN
EDGE OF THE NEW WARNING AREA WILL MOVE EAST DURING THE AFTERNOON
TOWARD THE MISSISSIPPI RIVER.
SNOWFALL AMOUNTS HAVE BEEN RAISED BASED ON REPORTS SO FAR AND
RUC/RADAR TRENDS.
THE WINDS SO FAR HAVE NOT GOTTEN AS STRONG AS EXPECTED. MANY AREAS
ARE ONLY 15 TO 25 MPH BUT MORE SITES ARE STARTING TO INCREASE TO
20 TO 30 MPH. GUSTS HAVE GENERALLY BEEN 30 MPH OR LESS SHOULD
INCREASE TO 35 MPH DURING THE AFTERNOON HOURS.
BASED ON RUC TRENDS...THE SNOW SHOULD RAPIDLY START SHUTTING DOWN
AROUND MID EVENING WITH LINGERING FLURRIES AFTER MIDNIGHT. AS
SUCH...THE EXPIRATION OF THE HEADLINES IN THE EASTERN CWFA HAVE
BEEN PULLED BACK TO 3 AM.
..08..
&&
.AVIATION...
SNOW WITH AREAS OF BLOWING SNOW AND IFR TO LIFR CONDITIONS EXPECTED
TO CONTINUE THROUGH THE AFTN. SNOW WILL TAPER TO FLURRIES THEN END
FROM NW TO SE THIS EVE WITH MVFR CIGS PREVAILING FOR MUCH OF THE
REST OF PD. WINDS GENERALLY NW AT 10-20 KTS WITH HIGHER GUSTS AT TIMES.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER STORM WARNING UNTIL 3 AM CST FRIDAY FOR CLINTON-JACKSON-
SCOTT.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BENTON-
BUCHANAN-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-KEOKUK-
LEE-LOUISA-MUSCATINE-VAN BUREN-WASHINGTON.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR CEDAR-
DELAWARE-DUBUQUE-JONES-LINN.
IL...WINTER STORM WARNING UNTIL 3 AM CST FRIDAY FOR CARROLL-JO
DAVIESS-ROCK ISLAND-STEPHENSON-WHITESIDE.
WINTER WEATHER ADVISORY UNTIL 3 AM CST FRIDAY FOR BUREAU-HANCOCK-
HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-WARREN.
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK-
SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
648 PM MST FRI JAN 13 2012
.UPDATE...
646 PM MST FRI JAN 13 2012
LATEST RUC AND HRRR CATCHING INCOMING SURFACE TROUGH FROM THE
NORTHWEST. THEY HAD THE STRENGTH/POSITION THE BEST WITH THE
REMAINING MODEL OUTPUT NOT STRONG ENOUGH. SO INCREASED WIND SPEEDS
OVER THE NORTHEAST PORTION OF THE AREA A LITTLE. ALSO BECAUSE OF
THE STRONGER WINDS RAISED THE MINS SOME THAT SAME AREA AS WELL.
OTHERWISE...JUST ADJUSTED HOURLY GRIDS.
BULLER
&&
.DISCUSSION...
208 PM MST FRI JAN 13 2012
TONIGHT...SHOULD SEE NORTHWEST WINDS OF 10 TO 20 MPH WINDS WITH
HIGHER GUSTS THROUGH MIDNIGHT BEHIND A DEPARTING UPPER LEVEL
DISTURBANCE. AFTER MIDNIGHT WINDS SUBSIDE A BIT INTO THE 10 MPH
RANGE. OVERNIGHT LOWS WILL BE A BIT WARMER THEN THE PAST FEW NIGHTS
AS WARM AIR ALOFT MOVES IN. WILL AIM FOR LOWS GENERALLY IN THE UPPER
TEENS TO LOW 20S IN FAR EASTERN COLORADO...LOW TO MID 20S EAST OF
THE CO/KS BORDER. THIS IS SEVERAL DEGREES WARMER THAN THE MAV AND
MET MOS GUIDANCE.
007
SATURDAY-SUNDAY...H5 RIDGE CONTINUES TO BUILD EAST TOWARDS CWA...WITH
DRY/STABLE AIR MASS IN PLACE THROUGH SUNDAY NIGHT. TEMPERATURES
WILL CONTINUE TO MODERATE OVER THE NEXT FEW DAYS...WITH HIGH TEMPS
IN THE 50S SATURDAY...AND MID/UPPER 50S ON SUNDAY. CONSIDERING
TEMPS ALOFT SAT/SUN NIGHTS...BUMPED LOWS TO THE UPPER 20S. THIS IS
ABOUT 5-10F ABOVE MOS GUIDANCE...HOWEVER CONSIDERING TEMPS ALOFT
AND POSSIBLE SKY COVER SUN NIGHT...THIS MAY STILL BE TOO COOL.
MONDAY-MONDAY NIGHT...TROUGH DEVELOPING OVER THE PACIFIC NW OVER THE
WEEKEND WILL PROGRESS EAST ACROSS THE GREAT BASIN TOWARDS THE CWA
MONDAY. GUIDANCE STILL DIFFERS BY ABOUT 6HR ON TIMING OF ASSOCIATED
COLD FRONT MONDAY...HOWEVER OVERALL TREND HAS BEEN TO SPEED UP
ARRIVAL...WITH FRONTAL PASSAGE LIKELY BY MIDDAY. PRECIP ASSOCIATED WITH
LARGE SCALE ASCENT ALONG LEADING EDGE OF TROUGH AXIS LOOKS TO ARRIVE
FROM THE NW LATE MONDAY AFTERNOON...QUICKLY MOVING EAST THROUGH THE
EVENING HOURS. GUIDANCE IN GOOD AGREEMENT ON STABLE/DRY AIR QUICKLY
MOVING IN AFTER 06Z...SO I TRENDED FORECAST IN THAT DIRECTION. I
KEPT BEST CHANCES DURING THE EVENING IN THE NORTH...AND LEFT A SMALL
AREA OF SLIGHT CHANCE POPS IN THE FAR EAST AFTER 06Z. CONSIDERING
LIMITED MOISTURE AND QUICK NATURE OF THIS SYSTEM...ONLY ANTICIPATING
LIGHT SNOW ACCUMULATIONS...ABOUT AN INCH OR LESS.
TUESDAY-FRIDAY...REMAINING FORECAST LOOKS DRY WITH W/NW FLOW
DEVELOPING ACROSS WESTERN CONUS...AND DRY/STABLE AIR MASS IN PLACE.
BIGGEST QUESTION THROUGH THESE PERIODS WILL BE HOW QUICKLY SHALLOW
COLD AIR MASS MODERATES...AND WHAT TEMPS WILL DO IN RESPONSE TO WEAK
SHORTWAVE TROUGHS EMBEDDED WITHIN MEAN FLOW. FOR NOW EXPECT BELOW
NORMAL TEMPS TUESDAY AND NEAR NORMAL TEMPS WEDNESDAY. GUIDANCE STILL
INDICATING RISING H5 HEIGHTS H85 TEMPS TO ABOUT 10-12C BY
FRIDAY...WHEN I KEPT FORECAST OF MID 50S IN THE WEST. THIS MAY END
UP BEING TOO COOL CONSIDERING CONDITIONS ALOFT...HOWEVER THERE IS
ENOUGH UNCERTAINTY IN REGARDS TO BOUNDARY LAYER DIFFERENCES TO
KEEP ME FROM CHANGING TOO MUCH THIS FAR OUT.
DR
&&
.AVIATION...
440 PM MST FRI JAN 13 2012
FOR THE 00Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
WIND FORECAST A LITTLE INTERESTING. EARLIER FORECAST HAD LIGHTER
WINDS OCCURRING DURING THE NIGHT. BELIEVE THE WINDS WILL BE
STRONGER...ESPECIALLY AT KMCK...BEGINNING NEAR 03Z AND CONTINUING
THROUGH THE REST OF THE NIGHT. BASE THIS ON STRONG SHORTWAVE UPPER
TROUGH MOVING ACROSS THE NORTH CENTRAL PORTION OF THE COUNTRY WHICH IS
PUSHING A SURFACE TROUGH THROUGH AT THIS TIME. STRONG SUBSIDENCE
SEEN ON SATELLITE AND DECENT GRADIENT OCCURRING BEHIND THE SYSTEM
AS SHOWN BY WINDS UPSTREAM. HIGH RESOLUTION GUIDANCE WOULD SUPPORT
SUSTAINED WINDS NEAR 15 KNOTS WITH GUSTS OCCURRING AT KMCK. SURFACE
RIDGE MOVES IN LATE TONIGHT TO DECREASE THE WIND AND THEN CAUSE
THE WINDS TO SHIFT TOWARD THE SOUTH DURING THE DAY.
BULLER
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1121 PM CST WED JAN 11 2012
.AVIATION...
FOR THE 06Z TAF ISSUANCE...
GUSTY NORTH WINDS AT AROUND 20KTS WILL CONTINUE THROUGH AT LEAST
09Z AS A 700MB COLD POOL CROSSES SOUTHWEST KANSAS. THESE GUSTY
WINDS ARE EXPECTED TO BRIEFLY SUBSIDE SLIGHTLY TOWARDS DAYBREAK
BUT WILL THEN REBOUND BACK TO AROUND 25 KNOTS BY MID MORNING AS
MIXING IMPROVES. AFTER 00Z FRIDAY THE WINDS WILL BEGIN TO DECREASE
AS THE SUNSETS AND THE ATMOSPHERE DECOUPLES. OTHER THAN SOME MID
LEVEL MOISTURE ACCOMPANYING THE COLD POOL EARLY THIS MORNING THE
BUFR SOUNDINGS INDICATING VFR CONDITIONS THROUGH THURSDAY NIGHT.
-RB
&&
PREV DISCUSSION... /ISSUED 203 PM CST WED JAN 11 2012/
SYNOPSIS...
12Z RAOB PLOT ANALYSIS INDICATES A LARGE TROUGH PUSHING ACROSS THE ROCKIES
AND INTO THE NORTHERN PLAINS. THIS FEATURE HAS USHERED IN A COLD FRONT
EARLY THIS MORNING ACROSS SOUTHWEST KANSAS. AS OF 18Z, THIS FRONT IS
STILL MOVING ACROSS OKLAHOMA. WINDS WERE STRONG BEHIND THE FRONT WITH
MANY OBSERVATION SITES ACROSS WESTERN KANSAS REPORTING WINDS AROUND
30 KT.
DISCUSSION...
DAYS 1-2...
TONIGHT:
SHORT TERM FOCUS IS WINDS. HAVE UPDATED THE WIND ADVISORY FOR THE ENTIRE
REGION AS AWOS SITES ACROSS FAR WESTERN KANSAS HAVE BEEN AT WIND ADVISORY
CRITERIA EARLIER. HRRR AND NAM SHOW THAT WINDS WILL QUICKLY TAPER TOWARDS
6 PM CST. SECOND SHORT TERM FOCUS IS IF WE WILL SEE PRECIPITATION. THE
NAM HAS VERY LIGHT QPF ACROSS CENTRAL KANSAS TONIGHT. HRRR ALSO INDICATES
LIGHT COMPOSITE REFLECTIVITY FORECAST SO HAVE PUT 20 POPS ACROSS THE
NORTHEAST/NORTH. ELSEWHERE, WILL KEEP AROUND 10 PERCENT WITH FLURRIES. THIS
ACTIVITY WILL DIMINISH THIS EVENING. OVERNIGHT LOWS WILL BE ON THE COLD
SIDE AS WINDS WEAKEN AND SKIES CLEAR. WINDS WILL NOT COMPLETELY CALM
SO DID NOT GET TOO CARRIED AWAY WITH LOWS.
THURSDAY/THURSDAY NIGHT:
ANOTHER WINDY DAY LOOKS LIKELY ACROSS SOUTHWEST KANSAS TOMORROW. THIS
IS IN ASSOCIATION WITH A TIGHT PRESSURE GRADIENT REMAINING OVER THE
AREA. HAVE INCREASED WINDS IN THE GRIDS IN THE 20 TO 30 MPH RANGE BUT
KEPT VALUES/GUSTS BELOW WIND ADVISORY CRITERIA. INSTEAD OF HAVING TWO
WIND ADVISORIES OUT, WHICH COULD BE CONFUSING...I WILL LET THE MID SHIFT
DECIDE IF WE NEED A WIND ADVISORY OR NOT. TOMORROWS HIGHS WILL BE IN
THE 30S DEG F. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE TEENS DEG F.
FRIDAY:
KANSAS WILL BE IN NORTHWEST FLOW ALOFT WHICH FAVORS A DRY FORECAST.
WILL KEEP POPS AT ZERO FRIDAY. COULD SEE SOME DOWNSLOPE WESTERLY WINDS
FRIDAY SO HAVE WARMED HIGHS UP A BIT. 850 HPA TEMPERATURES WARM UP INTO
THE LOWER SINGLE POSITIVE DIGITS DEG C, SO WE COULD SEE SOME MIXING
TO 40S DEG F AT THE SURFACE.
DAYS 3-7...
THE MID TO UPPER-LEVEL FLOW WILL GRADUALLY TRANSITION FROM
NORTHWESTERLY TO WEST-SOUTHWESTERLY FROM FRIDAY NIGHT INTO SUNDAY.
THUS, SURFACE PRESSURES WILL FALL IN THE LEE OF THE ROCKIES ALONG
WITH SOME WEAK LOW-LEVEL DOWNSLOPE FLOW. HIGH TEMPERATURES WILL
MODIFY INTO THE MID 50S BY SATURDAY AND 55 TO 60 BY SUNDAY.
A SHORTWAVE TROUGH WILL PROGRESS IN MAINLY ZONAL FLOW ACROSS THE
CENTRAL AND NORTHERN PLAINS BY MONDAY AND MONDAY NIGHT. THIS WILL
BRING SOME COLDER AIR INTO WESTERN KANSAS. SO AFTER A FAIRLY MILD
DAY MONDAY (50S TO LOWER 60S) JUST IN ADVANCE OF THE FRONT, HIGHS
WILL FALL INTO THE 30S OR LOWER 40S BY TUESDAY. NO PRECIPITATION CAN
BE EXPECTED IN THIS ZONAL PATTERN.
ANOTHER WARMING TREND IS EXPECTED BY JANUARY 18-19TH WITH HIGHS
POSSIBLY REACHING TO NEAR 70F IN A GENERALLY ZONAL MID TO UPPER-LEVEL
FLOW REGIME WITH LEE-TROUGHING AT LOW-LEVELS. HOWEVER, AS IS OFTEN
THE CASE IN ZONAL REGIMES, THERE WILL BE A SHARP TEMPERATURE
GRADIENT BETWEEN DOWNSLOPE FLOW OVER THE SOUTHERN AND CENTRAL PLAINS
AND ARCTIC AIR OVER THE NORTHERN PLAINS OR SOUTHERN CANADA. ANY
SHORTWAVE TROUGH TRAVERSING THE FLOW COULD RESULT IN ANOTHER SURGE
OF COLD AIR. THE ECMWF IS ADVERTISING ANOTHER SUCH COOLDOWN BY
JANUARY 20-21ST. NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH
JANUARY 21ST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 12 35 14 46 / 10 0 0 0
GCK 11 35 12 47 / 10 0 0 0
EHA 11 37 15 48 / 10 0 0 0
LBL 11 36 15 48 / 10 0 0 0
HYS 11 33 11 46 / 10 0 0 0
P28 17 37 15 46 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
1243 PM EST THU JAN 12 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE SOUTH TODAY AND WILL MOVE INTO
THE GULF OF MAINE BY THIS EVENING. LOW PRESSURE WILL WEAKEN AS IT
MOVES INTO THE MARITIMES TONIGHT. AT THE SAME TIME...ANOTHER AREA
OF LOW PRESSURE WILL APPROACH NEW ENGLAND FROM THE WEST. LOW
PRESSURE WILL MOVE NORTHEAST THROUGH NORTHERN NEW ENGLAND ON
FRIDAY SWINGING A TRAILING COLD FRONT THROUGH THE AREA AND SETTING
UP A STRONG SOUTHWEST FLOW IN IT`S WAKE. A TROUGH OF LOW PRESSURE
WILL LINGER OF THE AREA FRIDAY NIGHT AND WILL MOVE OFFSHORE ON
SATURDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST
SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL CREST OVER THE
REGION ON MONDAY AND SHIFT OFFSHORE IN THE AFTERNOON. A COLD FRONT
WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT THROUGH TUESDAY. LOW
PRESSURE WILL DEVELOP ALONG THE FRONT AND WILL MOVE INTO NORTHERN
NEW ENGLAND BY WEDNESDAY MORNING SWINGING THE FRONT THROUGH THE
REGION. LOW PRESSURE WILL RACE OFF TO THE NORTHEAST ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1742Z UPDATE...
HAVE ADDED A SMALL AREAS...COASTAL CUMBERLAND...LINCOLN AND SAGAHOC
COUNTIES TO THE WARNING BASED ON CURRENT CONDS AND OBS. VERY
LITTLE CHANGE TO THE SNOWFALL FORECAST...GOING FROM 3-6 INCHES TO
4-8 INCHES.
RADAR SHOWING A GOOD BATCH OF +SN TO CROSS THAT
REGION OVER THE NEXT HOUR OR TWO...DELIVERING 1" PER HOUR SNOWFALL
RATES BEFORE THE PCPN TAPERS OFF. ANOTHER NICE BATCH OF HEAVY PCPN
IS ROTATING NORTH FROM MASS AT THIS HOUR AS WELL.
UPDATE...
UPDATE WAS TO ADD WINTER STORM WARNINGS FOR SOUTH-CENTRAL NH PER
LATEST OBS/REPORTS OF SNOWFALL IN THAT AREA. WRN NH WILL BE
GETTING SHADDOWED SHORTLY...OTRW THEY WOULD HAVE BEEN INCLUDED AS
WELL.
TEMPS NOW WARMING ALONG THE COAST. CONSIDERED WARNINGS FOR PWM
NORTH...HOWEVER...READINGS NOW IN THE UPPER 20S/LOWER 30S AND
CLIMBING. A MIX IS NOW OCCURRING IN YORK COUNTY...AND IN THE
MIDCOAST REGION. WOULDN`T BE SURPRIZED HOWEVER IF A FEW LOCATIONS
BETWEEN PWM AND IWI RECEIVE LOCALLY 7" SNOWFALL.
PREV DISC..
COASTAL FRONT IN FULL SWING ALONG THE COAST WITH TEMPERATURES
FALLING QUICKLY ALONG THE SHORELINE. PORTLAND NOW DOWN TO 25
DEGREES...JUST WEST OF THE COASTAL FRONT (HAVE LOWERED MAX TEMP
FCST AND DEW POINT VALUES FOR TODAY). THIS COLD/DRY AIR WILL
CONTINUE TO FUNNEL DOWN THE COAST...AND WE HAVE ALREADY BEGUN TO
ADJUST SNOWFALL TOTALS UPWARDS ALONG PORTIONS OF THE COAST.
BEST PRESSURE FALLS WITH THE SURFACE LOW NOW SOUTH OF LONG ISLAND.
BELIEVE MODELS ARE OVERDOING THE WARM AIR...BOTH AT THE SURFACE
AND ALOFT. COASTAL ROCKINGHAM COUNTY AND SOUTHERNMOST PORTIONS OF
YORK COUNTY HOWEVER STILL REMAIN RELATIVELY VULVERNABLE TO THE MIX
OR CHANGEOVER TO RAIN. HOWEVER...WE ARE DELAYING THIS ONSET OF
MIXED PCPN BY A COUPLE HOURS THIS MORNING.
TIDES ARE STARTING TO RUN PRETTY HIGH ALONG THE COAST...WITH
BUILDING WAVES ALONG WITH DEVELOPING GALE FORCE WINDS. EXPECT
SPLASH-OVER NEAR THE TIME OF HIGH TIDE AND WILL ADD THIS TO
STATEMENTS AND/OR THE HWO SHORTLY.
WARNINGS/ADVISORIES...ALL LOOKS GOOD AT THE MOMENT. AM MONITORING
PORTIONS OF SOUTH-CENTRAL HAMPSHIRE AND THE MAINE COASTLINE FOR
POSSIBLE UPGRADES TO ADDITIONAL WARNINGS. WILL TAKE A QUICK LOOK
AT THE NEW NAM - WITH ONLY MODEST INTEREST AS IT HAS BEEN WAY TOO
WARM...BUT STRONG ON THE QPF FOR SW ME AND SE NH PROVIDING 1+" QPF
AS OF THE 06Z RUN. THIS AFTER RUNNING RELATIVELY DRY AT 00Z. MORE
IMPORTANTLY...WE`RE TAKING A GOOD LOOK AT THE LATEST HRRR MODEL
RUN. THIS MODEL BRINGS THE LOW OFF THE COAST OF MAINE LATER THIS
AFTERNOON AND BACKS WINDS WITH TIME...KEEPING WARM SURFACE AIR
OFFSHORE. HAVING MENTIONED SHORT RANGE GUIDANCE...WEIGHTING OF
THIS FORECAST IS HIGHLY DEPENDENT ON THE POSITIONING AND
ENHANCEMENT OF OUR FULLY DEVELOPED COASTAL FRONT.
PREV DISC...
LOW PRESSURE MOVING UP FROM THE SOUTH WILL BRING A VARIETY OF
PRECIPITATION TO THE REGION TODAY. EXPECT SNOW TO MOVE INTO
SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THROUGH DAYBREAK. TEMPS
ALREADY IN THE MID 30S IN COASTAL AREAS SO EXPECT PRECIPITATION TO
GO OVER TO RAIN FAIRLY QUICKLY THIS MORNING IN SOUTHEAST NEW
HAMPSHIRE AND ADJACENT SOUTHWEST COASTAL MAINE. EVAPORATIONAL
COOLING AT THE ONSET MAY LAST LONG ENOUGH TO PRODUCE AN INCH OR
TWO OF SNOW IN THESE AREAS BEFORE CHANGEOVER.
FARTHER TO THE NORTH IN SOUTH CENTRAL NEW HAMPSHIRE EXPECT MORE IN
THE WAY OF SNOW BEFORE MIXING TAKES PLACE WITH 3 TO 6 INCHES
LIKELY THROUGH EARLY AFTERNOON. LOOKING FOR PRECIPITATION TO
REMAIN IN THE FORM OF SNOW FOR MUCH OF THE DAY IN NORTHERN NEW
HAMPSHIRE AND INTERIOR SECTIONS OF MAINE WHICH COULD SEE AS MUCH
AS 6 TO 10 INCHES BEFORE PRECIPITATION WINDS DOWN AS A PERIOD OF
SLEET OR LIGHT FREEZING RAIN LATE THIS AFTERNOON AND THIS EVENING.
WILL BE STICKING WITH CURRENT ADVISORIES AND WARNINGS WITH NO
CHANGES PLANNED. EXPECT HIGHS IN THE MID 30S TO NEAR 40 IN COASTAL
AREAS BUT COLD AIR WILL HANG TOUGH IN INTERIOR SECTIONS WHERE
HIGHS WILL ONLY REACH THE MID 20S TO LOWER 30S.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
A LULL IN THE ACTION DURING THE FIRST HALF OF TONIGHT AS LOW
PRESSURE WEAKENS AND LIFTS NORTHEAST INTO THE MARITIMES. MAY SEE
SOME LIGHT PATCHY FREEZING DRIZZLE OR MIXED PRECIPITATION DURING
THE FIRST HALF OF THE NIGHT BUT ANY ACCUMULATIONS WILL BE MINOR.
LOW PRESSURE APPROACHING FROM THE GREAT LAKES WILL SWING AN
OCCLUSION NORTHEAST TOWARD NEW ENGLAND AFTER MIDNIGHT WHICH WILL
BRING ANOTHER ROUND OF MIXED PRECIPITATION INTO SOUTHWEST ZONES BY
DAYBREAK SO SOME FORM OF ADVISORIES MAY BE NEEDED FOR LATE TONIGHT
INTO FRIDAY.
EXPECT ACTIVITY ALONG THE BOUNDARY TO QUICKLY LIFT NORTHEAST
THROUGH THE REMAINDER OF THE FORECAST AREA DURING THE MORNING
HOURS...PERSISTING IN THE MOUNTAINS WELL INTO THE AFTERNOON WITH
MIXED PRECIPITATION CHANGING BACK TO SNOW AS COLDER AIR SHIFTS
BACK INTO THE REGION. COULD SEE SEVERAL INCHES OF ACCUMULATION
LATE IN THE DAY AS UPSLOPE FLOW KICKS IN BEHIND DEPARTING LOW.
ELSEWHERE RAIN AND MIXED PRECIPITATION WILL TAPPER TO SNOW SHOWERS
IN THE AFTERNOON.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT BRINGING IN CD
CANADIAN AIR ON GUSTY W THEN NW WINDS. SHSN PSBL...THOUGH MOSTLY
CONFINED TO THE N/MT ZONES WHERE SOME ACCUMULATION PSBL. ELSEWHERE
DOWNSLOPE WINDS HELP TO MINIMIZE THE CHC OF ANY SHSN AND ALSO
DECREASES AMOUNT OF SKY COVER VERSUS THE N/MT ZONES. CD WX
DOMINATES THRU THE WEEKEND AS THE NW WIND FIELD SLOWLY EASES UP
WITH HIGH PRES APPROACHING FROM THE W. THE HIGH SETTLES OVER THE E
COAST MONDAY WITH FAIR BUT CONTINUED CD WX. THE HIGH MOVES OFF
SHORE TUESDAY ALLOWING SW FLOW TO BRING IN WARMER AIR. AN
APPROACHING CD FNT BRINGS A CHC OF -SHSN OR -SHRA TUESDAY AND
TUESDAY NGT. THE STRONG ARCTIC FNT MOVES BY FOR WEDNESDAY BRINGING
IN MORE VERY CD AND BLUSTERY WX.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR FRIDAY
NGT AND SATURDAY. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...IFR/LIFR CEILINGS/VSBY DEVELOPING TODAY AND
PERSISTING THROUGH FRIDAY MORNING...IMPROVING IN THE AFTERNOON.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...STRONG ARCTIC CD FNT
MOVES THRU FRIDAY NGT WITH SHSN PSBL ALONG WITH MVFR TO IFR
CIG/VSBY...THOUGH MOST ACTIVITY CONFINED TO THE N/MT AREAS.
STRONG GUSTY W THEN NW WINDS FRIDAY NGT.
&&
.MARINE...
SHORT TERM...GALE WARNING EXTENDED THROUGH FRIDAY NIGHT.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...WILL EXTEND THE GLW
THRU FRIDAY NGT WITH EVEN A FEW PEAK GUSTS OF STORM FORCE PSBL AS
STRONG W FLOW SETS UP BEHIND DEPARTING STRONG CD FNT AND TIGHT
PRES GRADIENT SETS UP AND IS ENHANCED BY STRONG CD AIR ADVECTION
OVER THE WARMER WATERS. WINDS SLOWLY LET UP AND SEAS SLOWLY
SUBSIDE AS HIGH PRES BUILDS IN FROM THE W OVER THE WEEKEND AND
SETTLES OVER THE E COAST ON MONDAY.
&&
.TIDES/COASTAL FLOODING...
THE ASTRONOMICAL HIGH TIDE IN PORTLAND IS 10.3 FT ANEAR 1 PM THIS
AFTERNOON. A STORM SURGE OF 1 TO 1.5 FT IS EXPECTED TDA. THIS
WOULD PUSH THE TIDE TO AROUND 11.5 FT AND POSSIBLY CLOSE TO THE 12
FOOT TIDAL FLOOD STAGE. AT THIS TIME THE TIDE IS EXPECTED TO STAY
BELOW 12 FT. HOWEVER, BUILDING SEAS FROM ONSHORE WINDS WILL LIKELY
CREATE UP TO MODERATE SPLASHOVER AND BEACH EROSION AROUND THE TIME OF HIGH
TIDE.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
MEZ007>009-012>014-018>022-024>026.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MEZ023-027-028.
COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MEZ023-024.
NH...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
NHZ001>006-009-010.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NHZ007-008-013-014.
COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NHZ014.
MARINE...GALE WARNING UNTIL 7 AM EST SATURDAY FOR ANZ150>154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS GRAY ME
1113 AM EST THU JAN 12 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE SOUTH TODAY AND WILL MOVE INTO
THE GULF OF MAINE BY THIS EVENING. LOW PRESSURE WILL WEAKEN AS IT
MOVES INTO THE MARITIMES TONIGHT. AT THE SAME TIME...ANOTHER AREA
OF LOW PRESSURE WILL APPROACH NEW ENGLAND FROM THE WEST. LOW
PRESSURE WILL MOVE NORTHEAST THROUGH NORTHERN NEW ENGLAND ON
FRIDAY SWINGING A TRAILING COLD FRONT THROUGH THE AREA AND SETTING
UP A STRONG SOUTHWEST FLOW IN IT`S WAKE. A TROUGH OF LOW PRESSURE
WILL LINGER OF THE AREA FRIDAY NIGHT AND WILL MOVE OFFSHORE ON
SATURDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST
SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL CREST OVER THE
REGION ON MONDAY AND SHIFT OFFSHORE IN THE AFTERNOON. A COLD FRONT
WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT THROUGH TUESDAY. LOW
PRESSURE WILL DEVELOP ALONG THE FRONT AND WILL MOVE INTO NORTHERN
NEW ENGLAND BY WEDNESDAY MORNING SWINGING THE FRONT THROUGH THE
REGION. LOW PRESSURE WILL RACE OFF TO THE NORTHEAST ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
UPDATE WAS TO ADD WINTER STORM WARNINGS FOR SOUTH-CENTRAL NH PER
LATEST OBS/REPORTS OF SNOWFALL IN THAT AREA. WRN NH WILL BE
GETTING SHADDOWED SHORTLY...OTRW THEY WOULD HAVE BEEN INCLUDED AS
WELL.
TEMPS NOW WARMING ALONG THE COAST. CONSIDERED WARNINGS FOR PWM
NORTH...HOWEVER...READINGS NOW IN THE UPPER 20S/LOWER 30S AND
CLIMBING. A MIX IS NOW OCCURRING IN YORK COUNTY...AND IN THE
MIDCOAST REGION. WOULDN`T BE SURPRIZED HOWEVER IF A FEW LOCATIONS
BETWEEN PWM AND IWI RECEIVE LOCALLY 7" SNOWFALL.
PREV DISC..
COASTAL FRONT IN FULL SWING ALONG THE COAST WITH TEMPERATURES
FALLING QUICKLY ALONG THE SHORELINE. PORTLAND NOW DOWN TO 25
DEGREES...JUST WEST OF THE COASTAL FRONT (HAVE LOWERED MAX TEMP
FCST AND DEW POINT VALUES FOR TODAY). THIS COLD/DRY AIR WILL
CONTINUE TO FUNNEL DOWN THE COAST...AND WE HAVE ALREADY BEGUN TO
ADJUST SNOWFALL TOTALS UPWARDS ALONG PORTIONS OF THE COAST.
BEST PRESSURE FALLS WITH THE SURFACE LOW NOW SOUTH OF LONG ISLAND.
BELIEVE MODELS ARE OVERDOING THE WARM AIR...BOTH AT THE SURFACE
AND ALOFT. COASTAL ROCKINGHAM COUNTY AND SOUTHERNMOST PORTIONS OF
YORK COUNTY HOWEVER STILL REMAIN RELATIVELY VULVERNABLE TO THE MIX
OR CHANGEOVER TO RAIN. HOWEVER...WE ARE DELAYING THIS ONSET OF
MIXED PCPN BY A COUPLE HOURS THIS MORNING.
TIDES ARE STARTING TO RUN PRETTY HIGH ALONG THE COAST...WITH
BUILDING WAVES ALONG WITH DEVELOPING GALE FORCE WINDS. EXPECT
SPLASH-OVER NEAR THE TIME OF HIGH TIDE AND WILL ADD THIS TO
STATEMENTS AND/OR THE HWO SHORTLY.
WARNINGS/ADVISORIES...ALL LOOKS GOOD AT THE MOMENT. AM MONITORING
PORTIONS OF SOUTH-CENTRAL HAMPSHIRE AND THE MAINE COASTLINE FOR
POSSIBLE UPGRADES TO ADDITIONAL WARNINGS. WILL TAKE A QUICK LOOK
AT THE NEW NAM - WITH ONLY MODEST INTEREST AS IT HAS BEEN WAY TOO
WARM...BUT STRONG ON THE QPF FOR SW ME AND SE NH PROVIDING 1+" QPF
AS OF THE 06Z RUN. THIS AFTER RUNNING RELATIVELY DRY AT 00Z. MORE
IMPORTANTLY...WE`RE TAKING A GOOD LOOK AT THE LATEST HRRR MODEL
RUN. THIS MODEL BRINGS THE LOW OFF THE COAST OF MAINE LATER THIS
AFTERNOON AND BACKS WINDS WITH TIME...KEEPING WARM SURFACE AIR
OFFSHORE. HAVING MENTIONED SHORT RANGE GUIDANCE...WEIGHTING OF
THIS FORECAST IS HIGHLY DEPENDENT ON THE POSITIONING AND
ENHANCEMENT OF OUR FULLY DEVELOPED COASTAL FRONT.
PREV DISC...
LOW PRESSURE MOVING UP FROM THE SOUTH WILL BRING A VARIETY OF
PRECIPITATION TO THE REGION TODAY. EXPECT SNOW TO MOVE INTO
SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THROUGH DAYBREAK. TEMPS
ALREADY IN THE MID 30S IN COASTAL AREAS SO EXPECT PRECIPITATION TO
GO OVER TO RAIN FAIRLY QUICKLY THIS MORNING IN SOUTHEAST NEW
HAMPSHIRE AND ADJACENT SOUTHWEST COASTAL MAINE. EVAPORATIONAL
COOLING AT THE ONSET MAY LAST LONG ENOUGH TO PRODUCE AN INCH OR
TWO OF SNOW IN THESE AREAS BEFORE CHANGEOVER.
FARTHER TO THE NORTH IN SOUTH CENTRAL NEW HAMPSHIRE EXPECT MORE IN
THE WAY OF SNOW BEFORE MIXING TAKES PLACE WITH 3 TO 6 INCHES
LIKELY THROUGH EARLY AFTERNOON. LOOKING FOR PRECIPITATION TO
REMAIN IN THE FORM OF SNOW FOR MUCH OF THE DAY IN NORTHERN NEW
HAMPSHIRE AND INTERIOR SECTIONS OF MAINE WHICH COULD SEE AS MUCH
AS 6 TO 10 INCHES BEFORE PRECIPITATION WINDS DOWN AS A PERIOD OF
SLEET OR LIGHT FREEZING RAIN LATE THIS AFTERNOON AND THIS EVENING.
WILL BE STICKING WITH CURRENT ADVISORIES AND WARNINGS WITH NO
CHANGES PLANNED. EXPECT HIGHS IN THE MID 30S TO NEAR 40 IN COASTAL
AREAS BUT COLD AIR WILL HANG TOUGH IN INTERIOR SECTIONS WHERE
HIGHS WILL ONLY REACH THE MID 20S TO LOWER 30S.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
A LULL IN THE ACTION DURING THE FIRST HALF OF TONIGHT AS LOW
PRESSURE WEAKENS AND LIFTS NORTHEAST INTO THE MARITIMES. MAY SEE
SOME LIGHT PATCHY FREEZING DRIZZLE OR MIXED PRECIPITATION DURING
THE FIRST HALF OF THE NIGHT BUT ANY ACCUMULATIONS WILL BE MINOR.
LOW PRESSURE APPROACHING FROM THE GREAT LAKES WILL SWING AN
OCCLUSION NORTHEAST TOWARD NEW ENGLAND AFTER MIDNIGHT WHICH WILL
BRING ANOTHER ROUND OF MIXED PRECIPITATION INTO SOUTHWEST ZONES BY
DAYBREAK SO SOME FORM OF ADVISORIES MAY BE NEEDED FOR LATE TONIGHT
INTO FRIDAY.
EXPECT ACTIVITY ALONG THE BOUNDARY TO QUICKLY LIFT NORTHEAST
THROUGH THE REMAINDER OF THE FORECAST AREA DURING THE MORNING
HOURS...PERSISTING IN THE MOUNTAINS WELL INTO THE AFTERNOON WITH
MIXED PRECIPITATION CHANGING BACK TO SNOW AS COLDER AIR SHIFTS
BACK INTO THE REGION. COULD SEE SEVERAL INCHES OF ACCUMULATION
LATE IN THE DAY AS UPSLOPE FLOW KICKS IN BEHIND DEPARTING LOW.
ELSEWHERE RAIN AND MIXED PRECIPITATION WILL TAPPER TO SNOW SHOWERS
IN THE AFTERNOON.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT BRINGING IN CD
CANADIAN AIR ON GUSTY W THEN NW WINDS. SHSN PSBL...THOUGH MOSTLY
CONFINED TO THE N/MT ZONES WHERE SOME ACCUMULATION PSBL. ELSEWHERE
DOWNSLOPE WINDS HELP TO MINIMIZE THE CHC OF ANY SHSN AND ALSO
DECREASES AMOUNT OF SKY COVER VERSUS THE N/MT ZONES. CD WX
DOMINATES THRU THE WEEKEND AS THE NW WIND FIELD SLOWLY EASES UP
WITH HIGH PRES APPROACHING FROM THE W. THE HIGH SETTLES OVER THE E
COAST MONDAY WITH FAIR BUT CONTINUED CD WX. THE HIGH MOVES OFF
SHORE TUESDAY ALLOWING SW FLOW TO BRING IN WARMER AIR. AN
APPROACHING CD FNT BRINGS A CHC OF -SHSN OR -SHRA TUESDAY AND
TUESDAY NGT. THE STRONG ARCTIC FNT MOVES BY FOR WEDNESDAY BRINGING
IN MORE VERY CD AND BLUSTERY WX.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR FRIDAY
NGT AND SATURDAY. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
SHORT TERM...IFR/LIFR CEILINGS/VSBY DEVELOPING TODAY AND
PERSISTING THROUGH FRIDAY MORNING...IMPROVING IN THE AFTERNOON.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...STRONG ARCTIC CD FNT
MOVES THRU FRIDAY NGT WITH SHSN PSBL ALONG WITH MVFR TO IFR
CIG/VSBY...THOUGH MOST ACTIVITY CONFINED TO THE N/MT AREAS.
STRONG GUSTY W THEN NW WINDS FRIDAY NGT.
&&
.MARINE...
SHORT TERM...GALE WARNING EXTENDED THROUGH FRIDAY NIGHT.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...WILL EXTEND THE GLW
THRU FRIDAY NGT WITH EVEN A FEW PEAK GUSTS OF STORM FORCE PSBL AS
STRONG W FLOW SETS UP BEHIND DEPARTING STRONG CD FNT AND TIGHT
PRES GRADIENT SETS UP AND IS ENHANCED BY STRONG CD AIR ADVECTION
OVER THE WARMER WATERS. WINDS SLOWLY LET UP AND SEAS SLOWLY
SUBSIDE AS HIGH PRES BUILDS IN FROM THE W OVER THE WEEKEND AND
SETTLES OVER THE E COAST ON MONDAY.
&&
.TIDES/COASTAL FLOODING...
THE ASTRONOMICAL HIGH TIDE IN PORTLAND IS 10.3 FT ANEAR 1 PM THIS
AFTERNOON. A STORM SURGE OF 1 TO 1.5 FT IS EXPECTED TDA. THIS
WOULD PUSH THE TIDE TO AROUND 11.5 FT AND POSSIBLY CLOSE TO THE 12
FOOT TIDAL FLOOD STAGE. AT THIS TIME THE TIDE IS EXPECTED TO STAY
BELOW 12 FT. HOWEVER, BUILDING SEAS FROM ONSHORE WINDS WILL LIKELY
CREATE UP TO MODERATE SPLASHOVER AND BEACH EROSION AROUND THE TIME OF HIGH
TIDE.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
MEZ007>009-012>014-018>022.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MEZ023>028.
COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MEZ023-024.
NH...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
NHZ001>006-009-010.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NHZ007-008-013-014.
COASTAL FLOOD ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
NHZ014.
MARINE...GALE WARNING UNTIL 7 AM EST SATURDAY FOR ANZ150>154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS GRAY ME
900 AM EST THU JAN 12 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE SOUTH TODAY AND WILL MOVE INTO
THE GULF OF MAINE BY THIS EVENING. LOW PRESSURE WILL WEAKEN AS IT
MOVES INTO THE MARITIMES TONIGHT. AT THE SAME TIME...ANOTHER AREA
OF LOW PRESSURE WILL APPROACH NEW ENGLAND FROM THE WEST. LOW
PRESSURE WILL MOVE NORTHEAST THROUGH NORTHERN NEW ENGLAND ON
FRIDAY SWINGING A TRAILING COLD FRONT THROUGH THE AREA AND SETTING
UP A STRONG SOUTHWEST FLOW IN IT`S WAKE. A TROUGH OF LOW PRESSURE
WILL LINGER OF THE AREA FRIDAY NIGHT AND WILL MOVE OFFSHORE ON
SATURDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST
SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL CREST OVER THE
REGION ON MONDAY AND SHIFT OFFSHORE IN THE AFTERNOON. A COLD FRONT
WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT THROUGH TUESDAY. LOW
PRESSURE WILL DEVELOP ALONG THE FRONT AND WILL MOVE INTO NORTHERN
NEW ENGLAND BY WEDNESDAY MORNING SWINGING THE FRONT THROUGH THE
REGION. LOW PRESSURE WILL RACE OFF TO THE NORTHEAST ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
...BANDS OF HEAVY SNOW ABOUT TO ENTER MAINE AND NEW HAMPSHIRE
QUICKLY FROM THE SOUTH...
COASTAL FRONT IN FULL SWING ALONG THE COAST WITH TEMPERATURES
FALLING QUICKLY ALONG THE SHORELINE. PORTLAND NOW DOWN TO 25
DEGREES...JUST WEST OF THE COASTAL FRONT (HAVE LOWERED MAX TEMP
FCST AND DEW POINT VALUES FOR TODAY). THIS COLD/DRY AIR WILL
CONTINUE TO FUNNEL DOWN THE COAST...AND WE HAVE ALREADY BEGUN TO
ADJUST SNOWFALL TOTALS UPWARDS ALONG PORTIONS OF THE COAST.
BEST PRESSURE FALLS WITH THE SURFACE LOW NOW SOUTH OF LONG ISLAND.
BELIEVE MODELS ARE OVERDOING THE WARM AIR...BOTH AT THE SURFACE
AND ALOFT. COASTAL ROCKINGHAM COUNTY AND SOUTHERNMOST PORTIONS OF
YORK COUNTY HOWEVER STILL REMAIN RELATIVELY VULVERNABLE TO THE MIX
OR CHANGEOVER TO RAIN. HOWEVER...WE ARE DELAYING THIS ONSET OF
MIXED PCPN BY A COUPLE HOURS THIS MORNING.
TIDES ARE STARTING TO RUN PRETTY HIGH ALONG THE COAST...WITH
BUILDING WAVES ALONG WITH DEVELOPING GALE FORCE WINDS. EXPECT
SPLASH-OVER NEAR THE TIME OF HIGH TIDE AND WILL ADD THIS TO
STATEMENTS AND/OR THE HWO SHORTLY.
WARNINGS/ADVISORIES...ALL LOOKS GOOD AT THE MOMENT. AM MONITORING
PORTIONS OF SOUTH-CENTRAL HAMPSHIRE AND THE MAINE COASTLINE FOR
POSSIBLE UPGRADES TO ADDITIONAL WARNINGS. WILL TAKE A QUICK LOOK
AT THE NEW NAM - WITH ONLY MODEST INTEREST AS IT HAS BEEN WAY TOO
WARM...BUT STRONG ON THE QPF FOR SW ME AND SE NH PROVIDING 1+" QPF
AS OF THE 06Z RUN. THIS AFTER RUNNING RELATIVELY DRY AT 00Z. MORE
IMPORTANTLY...WE`RE TAKING A GOOD LOOK AT THE LATEST HRRR MODEL
RUN. THIS MODEL BRINGS THE LOW OFF THE COAST OF MAINE LATER THIS
AFTERNOON AND BACKS WINDS WITH TIME...KEEPING WARM SURFACE AIR
OFFSHORE. HAVING MENTIONED SHORT RANGE GUIDANCE...WEIGHTING OF
THIS FORECAST IS HIGHLY DEPENDENT ON THE POSITIONING AND
ENHANCEMENT OF OUR FULLY DEVELOPED COASTAL FRONT.
PREV DISC...
LOW PRESSURE MOVING UP FROM THE SOUTH WILL BRING A VARIETY OF
PRECIPITATION TO THE REGION TODAY. EXPECT SNOW TO MOVE INTO
SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THROUGH DAYBREAK. TEMPS
ALREADY IN THE MID 30S IN COASTAL AREAS SO EXPECT PRECIPITATION TO
GO OVER TO RAIN FAIRLY QUICKLY THIS MORNING IN SOUTHEAST NEW
HAMPSHIRE AND ADJACENT SOUTHWEST COASTAL MAINE. EVAPORATIONAL
COOLING AT THE ONSET MAY LAST LONG ENOUGH TO PRODUCE AN INCH OR
TWO OF SNOW IN THESE AREAS BEFORE CHANGEOVER.
FARTHER TO THE NORTH IN SOUTH CENTRAL NEW HAMPSHIRE EXPECT MORE IN
THE WAY OF SNOW BEFORE MIXING TAKES PLACE WITH 3 TO 6 INCHES
LIKELY THROUGH EARLY AFTERNOON. LOOKING FOR PRECIPITATION TO
REMAIN IN THE FORM OF SNOW FOR MUCH OF THE DAY IN NORTHERN NEW
HAMPSHIRE AND INTERIOR SECTIONS OF MAINE WHICH COULD SEE AS MUCH
AS 6 TO 10 INCHES BEFORE PRECIPITATION WINDS DOWN AS A PERIOD OF
SLEET OR LIGHT FREEZING RAIN LATE THIS AFTERNOON AND THIS EVENING.
WILL BE STICKING WITH CURRENT ADVISORIES AND WARNINGS WITH NO
CHANGES PLANNED. EXPECT HIGHS IN THE MID 30S TO NEAR 40 IN COASTAL
AREAS BUT COLD AIR WILL HANG TOUGH IN INTERIOR SECTIONS WHERE
HIGHS WILL ONLY REACH THE MID 20S TO LOWER 30S.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
A LULL IN THE ACTION DURING THE FIRST HALF OF TONIGHT AS LOW
PRESSURE WEAKENS AND LIFTS NORTHEAST INTO THE MARITIMES. MAY SEE
SOME LIGHT PATCHY FREEZING DRIZZLE OR MIXED PRECIPITATION DURING
THE FIRST HALF OF THE NIGHT BUT ANY ACCUMULATIONS WILL BE MINOR.
LOW PRESSURE APPROACHING FROM THE GREAT LAKES WILL SWING AN
OCCLUSION NORTHEAST TOWARD NEW ENGLAND AFTER MIDNIGHT WHICH WILL
BRING ANOTHER ROUND OF MIXED PRECIPITATION INTO SOUTHWEST ZONES BY
DAYBREAK SO SOME FORM OF ADVISORIES MAY BE NEEDED FOR LATE TONIGHT
INTO FRIDAY.
EXPECT ACTIVITY ALONG THE BOUNDARY TO QUICKLY LIFT NORTHEAST
THROUGH THE REMAINDER OF THE FORECAST AREA DURING THE MORNING
HOURS...PERSISTING IN THE MOUNTAINS WELL INTO THE AFTERNOON WITH
MIXED PRECIPITATION CHANGING BACK TO SNOW AS COLDER AIR SHIFTS
BACK INTO THE REGION. COULD SEE SEVERAL INCHES OF ACCUMULATION
LATE IN THE DAY AS UPSLOPE FLOW KICKS IN BEHIND DEPARTING LOW.
ELSEWHERE RAIN AND MIXED PRECIPITATION WILL TAPPER TO SNOW SHOWERS
IN THE AFTERNOON.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A STRONG ARCTIC CD FNT MOVES THRU FRIDAY NGT BRINGING IN CD
CANADIAN AIR ON GUSTY W THEN NW WINDS. SHSN PSBL...THOUGH MOSTLY
CONFINED TO THE N/MT ZONES WHERE SOME ACCUMULATION PSBL. ELSEWHERE
DOWNSLOPE WINDS HELP TO MINIMIZE THE CHC OF ANY SHSN AND ALSO
DECREASES AMOUNT OF SKY COVER VERSUS THE N/MT ZONES. CD WX
DOMINATES THRU THE WEEKEND AS THE NW WIND FIELD SLOWLY EASES UP
WITH HIGH PRES APPROACHING FROM THE W. THE HIGH SETTLES OVER THE E
COAST MONDAY WITH FAIR BUT CONTINUED CD WX. THE HIGH MOVES OFF
SHORE TUESDAY ALLOWING SW FLOW TO BRING IN WARMER AIR. AN
APPROACHING CD FNT BRINGS A CHC OF -SHSN OR -SHRA TUESDAY AND
TUESDAY NGT. THE STRONG ARCTIC FNT MOVES BY FOR WEDNESDAY BRINGING
IN MORE VERY CD AND BLUSTERY WX.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR FRIDAY
NGT AND SATURDAY. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...IFR/LIFR CEILINGS/VSBY DEVELOPING TODAY AND
PERSISTING THROUGH FRIDAY MORNING...IMPROVING IN THE AFTERNOON.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...STRONG ARCTIC CD FNT
MOVES THRU FRIDAY NGT WITH SHSN PSBL ALONG WITH MVFR TO IFR
CIG/VSBY...THOUGH MOST ACTIVITY CONFINED TO THE N/MT AREAS.
STRONG GUSTY W THEN NW WINDS FRIDAY NGT.
&&
.MARINE...
SHORT TERM...GALE WARNING EXTENDED THROUGH FRIDAY NIGHT.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...WILL EXTEND THE GLW
THRU FRIDAY NGT WITH EVEN A FEW PEAK GUSTS OF STORM FORCE PSBL AS
STRONG W FLOW SETS UP BEHIND DEPARTING STRONG CD FNT AND TIGHT
PRES GRADIENT SETS UP AND IS ENHANCED BY STRONG CD AIR ADVECTION
OVER THE WARMER WATERS. WINDS SLOWLY LET UP AND SEAS SLOWLY
SUBSIDE AS HIGH PRES BUILDS IN FROM THE W OVER THE WEEKEND AND
SETTLES OVER THE E COAST ON MONDAY.
&&
.TIDES/COASTAL FLOODING...
THE ASTRONOMICAL HIGH TIDE IN PORTLAND IS 10.3 FT ANEAR 1 PM THIS
AFTERNOON. A STORM SURGE OF 1 TO 1.5 FT IS EXPECTED TDA. THIS
WOULD PUSH THE TIDE TO AROUND 11.5 FT AND POSSIBLY CLOSE TO THE 12
FOOT TIDAL FLOOD STAGE. AT THIS TIME THE TIDE IS EXPECTED TO STAY
BELOW 12 FT. HOWEVER, BUILDING SEAS FROM ONSHORE WINDS WILL LIKELY
CREATE UP TO MODERATE SPLASHOVER AND BEACH EROSION AROUND THE TIME OF HIGH
TIDE.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
MEZ007>009-012>014-018>022.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MEZ023>028.
NH...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
NHZ001>004-006.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NHZ005-007>010-013-014.
MARINE...GALE WARNING UNTIL 7 AM EST SATURDAY FOR ANZ150>154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS CARIBOU ME
102 AM EST THU JAN 12 2012
.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST OVERNIGHT. LOW PRESSURE WILL APPROACH
FROM THE SOUTHWEST THURSDAY AND TRACK THROUGH THE GULF OF MAINE
THURSDAY NIGHT. ANOTHER LOW WILL MOVE NORTH THROUGH NEW ENGLAND
FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE 0100L...
FIRST ISSUE WAS TO RAISE OVERNIGHT INTO EARLY MORNING TEMPS DUE TO
THICKENING CLOUD COVER. ALSO BROUGHT LOWER CLOUDS INTO DOWN EAST
EARLY THIS MORNING AS COASTAL FRONT ORGANIZES WITH SIGNIFICANT
TEMPERATURE GRADIENT ALONG COAST. WITH SOME COLD AIR DAMMING
SETTING UP...LOOKED AT NORMALLY COLD RUC OUTPUT AND IT IS BRINGING
IN WARM AIR RIGHT ALONG THE COAST AND A WARM LAYER ALOFT NEAR H850
EARLIER THAN OTHER MODELS. THIS MEANS LESS SNOW ACCUMULATION ALONG
THE COAST AND NORTHWARD TO BGR DUE TO MIXED PRECIP. NEW
EXPECTATION IS JUST OVER 4 INCHES AROUND BGR AND DROPPING OFF TO
THE ONE TO THREE INCH RANGE IN THE ZONES 29 AND 30 WITH THE LOWEST
VALUES ALONG THE COAST AND OUTER ISLANDS. THE BEST SNOW
ACCUMULATIONS SHOULD BE ALONG THE HIGHER TERRAIN FROM JUST SOUTH
OF GREENVILLE TOWARDS PATTEN AND SHIN POND WHERE COLDER AIR ALOFT
AND UPSLOPE SHOULD MAXIMIZE SNOWFALL.
UPDATE...
HIGH PRESSURE WILL MOVE EAST OVERNIGHT WHILE LOW PRESSURE DEVELOPS
ALONG THE MID ATLANTIC COAST. SKIES WILL BE CLOUDY ACROSS THE
FORECAST AREA OVERNIGHT. LOW TEMPERATURES TONIGHT WILL GENERALLY
RANGE FROM AROUND ZERO NORTH...TO 10 TO 15 DOWNEAST. HAVE UPDATED
THE FORECAST TO ADJUST FOR CURRENT CONDITIONS ALONG WITH EXPECTED
OVERNIGHT CLOUDS/TEMPERATURES.
PREVIOUS DISCUSSION...
THE LOW PRESSURE CENTER WITH THE SYSTEM THURSDAY WILL TRACK
NORTHEAST RIGHT ALONG THE COAST IN THE AFTERNOON AND THURSDAY
NIGHT. NEARLY ALL THE PRECIPITATION AND STRONGER WINDS WILL BE ON
THE LEADING EDGE OF THE SURFACE LOW...AS THE UPPER LEVEL TROUGH
AND DYNAMICS ARE EASILY OUTPACING THE SURFACE LOW.
LOOK FOR SNOW TO BEGIN AROUND MIDDAY OVER SOUTHERN
MAINE...SPREADING NORTH TO THE ENTIRE AREA BY LATE AFTERNOON OR
EVENING. THE BEST DYNAMICS SUCH AS THE STRONGEST LIFT AND WARM
ADVECTION WILL BE OVER SOUTHEAST HALF OF THE AREA WITH THE HIGHEST
PRECIPITATION AMOUNTS THERE. HOWEVER...TEMPERATURES WILL BE ON THE
RISE THROUGH THE EVENT WITH LOWERING SNOW RATIOS AND MIXED
PRECIPITATION TOWARD THURSDAY EVENING PROBABLY KEEPING SNOW TOTALS
AT FOUR TO SIX INCHES...JUST BELOW WARNING CRITERIA.
FURTHER NORTH...EXPECT THE PRECIPITATION TYPE TO BE ALL SNOW
NORTHWEST OF HOULTON FOR THIS FIRST ROUND LATE THURSDAY/THURSDAY
NIGHT. THE PRECIPITATION WILL NOT BE AS HEAVY UP NORTH...SO EXPECT
ABOUT THREE OR FOUR INCHES OF SNOW FOR THE SAINT JOHN VALLEY SOUTH
TO CARIBOU AND PRESQUE ISLE. AGAIN...THIS IS JUST REFERRING TO THE
FIRST ROUND THURSDAY/THURSDAY NIGHT.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
INTENSE LOW PRESSURE MOVES INTO THE GREAT LAKES THURSDAY EVENING
WHILE SECONDARY LOW CENTER DEVELOPS IN THE GULF OF MAINE. THE
SECONDARY LOW WILL MOVE THROUGH THE GULF OF MAINE THURSDAY NIGHT
THEN INTO NEW BRUNSWICK FRIDAY MORNING. THE PRIMARY LOW WILL MOVE
FROM GREAT LAKES NORTHEASTWARD ACROSS FAR NORTHERN MAINE FRIDAY.
EXPECT HEAVIES SNOW FROM PRIMARY LOW TO STAY NORTHWEST OF THE
FORECAST AREA FRIDAY WHILE RESULTING IN MIXED PRECIPITATION OVER
THE REMAINDER OF THE REGION. GFS...NAM12 AND ECMWF INDICATE
HIGHEST AMOUNTS SOUTH. WITH COLD AIR DAMMING INLAND...SEA SURFACE
TEMPERATURE IN MID 40S AND SOME INSTABILITY ALOFT EXPECT COASTAL
FRONT TO BE FACTOR IN ENHANCING QPF AMOUNT SOUTH. FOR POPS HAVE
BLENDED THE NAM12...GFS40 AND SREF THEN MANUALLY ADJUSTED.
TEMPERATURE GRIDS RUN ON NAM12 INTO FRIDAY EVENING THEN TRANSITION
TO GMOS. PRECIPITATION TYPE GENERATED WITH THICKNESS TOOL RUN ON
50/50 BLEND OF THE NAM AND GFS. SNOW AMOUNT GENERATED WITH
OFFICE SNOW FROM THICKNESS RUN ON NAM12.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE EXTENDED MODELS ARE IN GOOD GENERAL AGREEMENT THROUGH THE
PERIOD. HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE AREA
THROUGH EARLY TUESDAY AFTERNOON. A LOW PRESSURE SYSTEM THAT STARTS
IN THE SOUTHERN PLAINS ON MONDAY WILL TRACK NORTHEAST INTO THE
GREAT LAKES REGION BY EARLY TUESDAY MORNING. THIS LOW WILL MOVE
INTO SOUTHERN QUEBEC BY TUESDAY AFTERNOON WITH ITS COLD FRONT
EXTENDED SOUTH ALONG THE BOARDER WITH MAINE. BY EARLY WEDNESDAY
MORNING THE COLD FRONT WILL PUSH THROUGH THE AREA AND HIGHER
PRESSURE WILL BUILD INTO THE REGION THROUGH THE END OF THE PERIOD.
LOADED GMOS. ADJUSTED SKY AND POP GRIDS TO BETTER SUPPORT ONE
ANOTHER. LOADED NAWAVE 4 FOR SEAS. PLUS 15 PERCENT FOR WINDS GUST
OVER LAND 20 PERCENT OVER WATER.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
NEAR TERM: VFR CONDITIONS ARE EXPECTED ACROSS THE REGION OVERNIGHT.
CONDITIONS WILL LOWER TO MVFR/IFR LEVELS...FROM SOUTH TO NORTH
ACROSS THE REGION...THURSDAY WITH PRECIPITATION EXPANDING NORTH.
SHORT TERM: EXPECT IFR/MVFR CONDITIONS THROUGH FRIDAY NIGHT THEN
VFR CONDITIONS SATURDAY THROUGH MONDAY.
&&
.MARINE...
NEAR TERM: CONDITIONS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY
LEVELS OVERNIGHT. WINDS WILL THEN RAPIDLY INCREASE TO GALE LEVELS
THURSDAY...WITH A GALE WARNING IN EFFECT STARTING THURSDAY
AFTERNOON. VISIBILITIES WILL LOWER IN DEVELOPING SNOW AND RAIN
THURSDAY.
SHORT TERM: HAVE USED THE NAM12 FOR WIND GRIDS. FOR WAVES HAVE
USED THE SWAN/NAM UNTIL 0000Z SATURDAY THEN TRANSITION TO THE WNA/4.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR MEZ001-002.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR MEZ003>006-011.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 1 PM EST FRIDAY FOR
MEZ016-017-029-030.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 7 PM EST FRIDAY FOR
MEZ010-015-031.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST
FRIDAY FOR MEZ032.
MARINE...GALE WARNING FROM NOON TODAY TO 10 PM EST THIS EVENING FOR
ANZ050>052.
&&
$$
NEAR TERM...FOISY/MCW
SHORT TERM...MIGNONE
LONG TERM...NORTON
AVIATION...FOISY/MCW
MARINE...FOISY/MCW/MIGNONE
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1106 PM EST WED JAN 11 2012
.SYNOPSIS...
LOW PRESSURE WILL BRING RAIN SHOWERS INTO THURSDAY. HIGHER MOUNTAINS
MAY UNDERGO A PERIOD OF FREEZING RAIN AND DENSE FOG OVERNIGHT. A
STRONG COLD FRONT WILL CAUSE A FAST TEMPERATURE DROP AND CHANGE TO
SNOW SHOWERS AND SLIPPERY CONDITIONS LATE THURSDAY NIGHT, AND BE
ACCOMPANIED BY GUSTY WIND THAT WILL CONTINUE INTO FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
PER RECENT SURFACE AND RADAR DATA, COUPLED WITH RECENT HRRR AND
WRF-NMM MODEL OUTPUT, EXPECT PATCHES OF FREEZING RAIN AND DENSE
FOG OVERNIGHT. HAVE ISSUED A FREEZING RAIN ADVISORY TIL 6 AM FOR
TUCKER COUNTY WV AND GARRETT COUNTY MD.
AS LOW PRESSURE CENTER GETS CLOSER, SHOWERS HAVE DECREASED IN
COVERAGE WEST OF THE MOUNTAINS. WIND HAVE BEGUN GUSTING OVER 30
MPH DOWNWIND OF THE SOUTHERN MOUNTAINS, WHICH WILL HAVE TO BE
MONITORED.
RECENT MODEL OUTPUT SUGGEST THERE CAN BE A SECOND SURGE OF SHOWERS
LATE TONIGHT INTO FRIDAY MORNING, MAINLY NEAR THE MOUNTAINS.
TEMPERATURES WILL BE NEARLY STEADY IN SOUTHERLY FLOW ON FRONT
SIDE OF SYSTEM. LOW PRESSURE EXITS DURING THE DAY THURSDAY WITH
SHOWERS DIMINISHING DURING THE MORNING. TEMPERATURES WILL STAY
ABOVE NORMAL THURSDAY AHEAD OF APPROACHING COLD FRONT.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
BLEND OF RECENT SREF MODEL OUTPUT SHOWS STRONG COLD FRONT WILL
MOVE EASTWARD THROUGH THE UPPER OHIO VALLEY THURSDAY NIGHT. THIS
WILL CAUSE A FAST TEMPERATURE DROP AND SUBSEQUENT FAST CHANGE OF
RAIN SHOWERS TO SNOW SHOWERS TOWARD MIDNIGHT. THE FAST CHANGE CAN
RESULT IN ICY CONDITIONS QUICKLY DEVELOPING WHICH HAS BEEN
MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK.
WITH COLD FLOW BEING MAINLY FROM THE WEST AND SOUTHWEST, EXPECT
SNOW ACCUMULATION AMOUNT TO BE IN SUBADVISORY RANGE LATE THURSDAY NIGHT
INTO DAYTIME FRIDAY. HOWEVER, IMPACT OF ICING CONDITIONS MAY ALSO
BE A PLAYER IN HEADLINE DECISIONS.
NAM MODEL PROFILES SHOW POST FRONTAL WIND GUSTS CAN REACH THE 30
TO 40 MPH RANGE LATE THURSDAY NIGHT AND FRIDAY.
AS SYSTEM MOVES TO NEW ENGLAND SATURDAY, SCATTERED SNOW SHOWERS
WILL CONTINUE WITH WINDS ONLY SLOWLY DIMINISHING.
FORECASTED TEMPERATURES CLOSE TO BLEND OF GFS AND NAM MOS WHICH
LOOK TO HAVE A GOOD HANDLE ON COLD AIR.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ANOTHER SHORTWAVE TROUGH AND ASSOCIATED SURFACE WEAK LOW IS PROGGED
TO CROSS THE OHIO VALLEY SATURDAY NIGHT AND EARLY SUNDAY BRINGING
SCATTERED SNOW SHOWERS. RIDGING AT THE SURFACE AND ALOFT SHOULD
PROVIDE DRY WEATHER LATER SUNDAY INTO MONDAY.
THE NEXT UPPER TROUGH WILL SWING A COLD FRONT ACROSS THE GREAT
LAKES REGION TUESDAY...ALONG WITH SCATTERED RAIN AND SNOW
SHOWERS. PRECIPITATION IS FORECAST TO TAPER OFF WEDNESDAY WITH
JUST A FEW LINGERING SHOWERS NORTH AND ALONG THE RIDGES.
NEAR NORMAL TEMPERATURES SHOULD MODERATE TO BETWEEN 5 AND 10 DEGREES
ABOVE NORMAL BY TUESDAY...AND RETURN TO NEAR NORMAL BY MIDWEEK.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
WIDESPREAD RAIN ACROSS WESTERN PENNSYLVANIA TAPERS OFF ACROSS
EASTERN OHIO AND NORTHERN WEST VIRGINIA. CONDITIONS RANGE FROM IFR
AT FKL AND DUJ TO VFR SOUTH OF PITTSBURGH. AS RAIN SHIELD CONTINUES
TO MOVE TO THE NORTH...EXPECT THAT ALL SITES WILL RISE TO VFR FOR AT
LEAST A FEW HOURS. WITH SO MUCH MOISTURE AROUND...EXPECT THAT
CEILINGS WILL DROP BACK TO IFR AT ALL TERMINALS. WINDS AROUND 10 KT
SHOULD DECREASE SLIGHTLY OVERNIGHT. HOWEVER...LOW LEVEL WIND SHEAR
IS EXPECTED TO DEVELOP FOR A FEW HOURS AT ALL SITES EXCEPT ZZV. LLWS
WILL NOT PERSIST FOR TOO LONG...DIMINISHING BY MIDNIGHT.
WHILE A CHANCE OF SHOWERS REMAINS IN THE FORECAST ON
THURSDAY...COVERAGE IS NOT HIGH ENOUGH TO WARRANT MENTION IN TAFS AT
THIS TIME. IFR CONDITIONS MAY RISE TO MVFR BY THE AFTERNOON. GUSTY
WINDS WILL DEVELOP...WITH 20 KTS EXPECTED ON THURSDAY AFTERNOON AND
DIMINISHING AT SUNSET.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
COLDER AIR WILL PUSH INTO THE REGION THURSDAY NIGHT AND CHANGE
PRECIPITATION OVER TO SNOW SHOWERS. SURFACE WIND GUSTS OVER 30KT ARE
POSSIBLE THURSDAY NIGHT AND FRIDAY. MVFR AND AREAS OF IFR
RESTRICTIONS WILL CONTINUE THROUGH SATURDAY MORNING.
SCATTERED SNOW SHOWERS SHOULD TAPER OFF DURING THE DAY SATURDAY.
ANOTHER LOW PRESSURE SYSTEM WILL SWING ACROSS THE OH VALLEY
SUNDAY...BRINGING THE POTENTIAL FOR RESTRICTIONS. A SURFACE RIDGE IS
PROGGED TO BUILD IN SUNDAY NIGHT AND MONDAY...WITH CONDITIONS
EXPECTED TO IMPROVE TO VFR.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FREEZING RAIN ADVISORY UNTIL 6 AM EST THURSDAY FOR MDZ001.
OH...NONE.
PA...NONE.
WV...FREEZING RAIN ADVISORY UNTIL 6 AM EST THURSDAY FOR WVZ041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1244 PM EST THU JAN 12 2012
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.UPDATE...
LATEST RADAR IMAGERY IS SHOWING AN INCREASE IN AREAL COVERAGE OF
SNOWFALL ACROSS THE SOUTH CENTRAL PORTIONS OF THE CWA. GIVEN RADAR
TRENDS IN ADDITION TO SUPPORT FROM THE HRRR AND 12Z RUN OF THE LOCAL
WRF PLACING HIGHER QPF FARTHER EAST...HAVE OPTED TO PUT MENOMINEE
COUNTY IN A WINTER WEATHER ADVISORY. OBSERVATIONS ARE ALSO
INDICATING THAT SNOW TO LIQUID RATIOS ARE TRENDING SLIGHTLY HIGHER
IN THIS REGION. RESULTING SNOW TOTALS SHOULD BE 2 TO 5 INCHES...WITH
THE HIGHEST AMOUNTS ACROSS THE SOUTHERN HALF OF THE COUNTY. THE
HEAVIEST SNOW SHOULD FALL DURING THE AFTERNOON AND EVENING.
ELSEWHERE...COVERAGE OF THE SNOW REMAINS ON TRACK. A SLIGHT INCREASE
IN POPS WERE MADE FROM MUNISING TO ESCANABA FOR THIS AFTERNOON TO
ACCOUNT FOR THE CURRENT TRENDS AND SHARP EDGE OF THE PRECIPITATION
SHIELD. FATHER WEST...LAKE ENHANCEMENT ACROSS PORTIONS OF MARQUETTE
AND BARAGA COUNTY ARE HAS BECOME WELL ESTABLISHED OVER THE PAST
HOUR.
AS FOR TEMPERATURES...HIGHS HAVE LIKELY ALREADY OCCURRED ACROSS MUCH
OF THE CWA AS CONTINUOUS CAA AND THICK CLOUD COVER RESULT IN STEADY
OR SLIGHTLY DECREASING TEMPERATURES THROUGHOUT THE AFTERNOON.
PATCHY FOG ACROSS INTERIOR LOCATIONS OF THE EASTERN CWA SHOULD
DISSIPATE QUICKLY BY EARLY AFTERNOON. WINDS HAVE BECOME NORTHERLY AT
KERY AND VIS HAS INCREASED SLIGHTLY OVER THE LAST HOUR.
&&
.DISCUSSION...
WATER VAPOR LOOP SHOWS MID-UPR TROUGH DIGGING THROUGH THE CENTRAL
PLAINS. 3H JET MAX ROUNDING THE BASE OF THIS TROUGH AND ASSOC
DIVERGENCE IN LEFT EXIT REGION OF THIS JET WILL AID IN RAPID
DEEPENING OF SFC LOW/STORM SYSTEM OVER NRN OHIO ATTM. THIS STORM
SYSTEM AND FAIRLY DEEP MOISTURE WRAPPING AROUND IT WILL HELP BRING
SIGNIFICANT LAKE ENHANCED TO PORTIONS OF WEST AND NCNTRL UPPER MI
THROUGH FRIDAY.
TODAY...PERSISTENT 800-700 MB FGEN HAS HELPED SUSTAIN OCCASIONALLY
MODERATE SNOW FM MQT INTO DICKINSON COUNTY AS NOTED ON LATEST RADAR
LOOP. MODELS SHOW FGEN PERSISTING INTO THE EARLY AFTERNOON HRS OVER
GENERALLY THIS SAME AREA SO WOULD NOT BE SURPRISED TO SEE MODERATE
SNOW CONTINUE AT TIMES. WHILE WRN COUNTIES WILL BE FARTHER AWAY FROM
SYNOPTIC FORCING FROM STORM SYSTEM OVER THE CENTRAL GREAT
LAKES...CONVERGENT NRLY FLOW AND GREATER INSTABILITY FROM COLDER
850 MB TEMPS OF -12 TO -14C...ALONG WITH FAVORABLE DENDRITIC SNOW
GROWTH AND TERRAIN ENHANCED LIFT WILL AID MODERATE TO HEAVY SNOW
ACCUMULATIONS. EXPECT 2 TO 5 INCHES OVER THESE AREAS WHERE WINTER
STORMS WARNINGS ARE ALREADY IN PLACE. ALSO LOOK FOR HIGHER TERRAIN
OF BARAGA AND WRN MQT TO SEE 3 TO 5 INCHES OF ACCUMULATION WHERE
WEAK TO MODERATE SYNOPTIC FORCING AND UPSLOPE ENHANCED LIFT SHOULD
OVERCOME MARGINAL INSTABILITY...SO WARNING STILL LOOKS GOOD FOR
THESE COUNTIES AS WELL. KEPT ADVISORY GOING FOR SRN HOUGHTON...IRON
AND DICKINSON COUNTIES THROUGH TONIGHT ALTHOUGH I AM A BIT CONCERNED
THAT SNOW COULD TAPER OFF QUICKLY TONIGHT FOR DICKINSON AND IRON AND
SOME AREAS COULD HAVE A HARD TIME REACHING ADVISORY CRITERIA (2-4
INCHES/12 HR).
ISSUED A WINTER WX ADVISORY FOR ALGER COUNTY THIS AFTERNOON THROUGH
FRIDAY AS NORTHERLY FLOW AND INCREASING INSTABILITY FROM COLDER
TEMPS MOVING IN FROM THE WEST LATER THIS AFTERNOON AND TONIGHT
SHOULD GET LAKE ENHANCED SNOW PRETTY GOOD ESPECIALLY OVER THE WRN
HALF OF THE COUNTY. LOOK FOR TOTAL ACCUMS OF 6 TO 10 INCHES THIS
AFTERNOON THROUGH FRIDAY OVER ALGER.
CANCELLED WATCH FOR NRN SCHOOLCRAFT AND OPTED NOT TO ISSUE ANY
HEADLINES FOR NRN SCHOOLCRAFT OR LUCE COUNTY AS CYCLONIC NNE FLOW
WILL NOT BE A FAVORABLE FETCH ACROSS LAKE SUPERIOR TO RECEIVE
SIGNIFICANT LES ACCUMS THROUGH FRIDAY.
TONIGHT...WITH SFC LOW/850MB LOWS WELL SE OF THE AREA OVER LAKE
HURON...POTENTIAL FOR SIGNIFICANT SYNOPTIC SNOW LOOKS LIMITED AND
MODELS GENERALLY SHOW A DIMINISHING TREND TO SNOW OVER AREAS AWAY
FROM LAKE SUPERIOR BY THIS EVENING. EXPECT NO MORE THAN AN INCH
OR TWO OF SYNOPTIC SNOW TONIGHT. CLOSE TO LAKE SUPERIOR...IT WILL BE
A FAVORABLE SETUP FOR LAKE ENHANCEMENT IN THE N WIND FAVORED AREAS.
AS COLDER AIR SPREADS IN FROM THE WEST TONIGHT THE DENDRITIC SNOW
GROWTH ZONE (DGZ) WILL FALL FIRMLY INTO THE CONVECTIVE BOUNDARY
LAYER (FM 1-3 KFT OFF FCST SNDGS) WHILE TERRAIN ENHANCED UPWARD
MOTION LAYER WILL ALSO AID LIFT IN THIS LYR. INCREASING SNOW-TO-WATER
RATIOS SHOULD RESULT IN MDT/POSSIBLY HVY SNOW ACCUMULATIONS W AND
NCNTRL. COMBINED WITH GUSTY WINDS...BLOWING AND DRIFTING SNOW WILL
ALSO ADD TO HAZARDOUS CONDITIONS ON AREA ROADS. WOULD NOT BE
SURPRISED TO SEE 6-8 INCH AMOUNTS TONIGHT WHERE TERRAIN ENHANCEMENT
IS MAXIMIZED (AROUND KIWD AND HURON MTNS).
FRIDAY...MUCH DRIER AIR WILL MAKE SHARP INROADS FROM W TO E FRI WITH
INVERSION HGTS FALLING AT OR BLO 3KFT. AS A RESULT...SNOW
INTENSITY WILL DIMINISH SIGNIFICANTLY FROM W TO E THRU THE DAY (W IN
THE MORNING...E IN THE AFTN). ALTHOUGH CONVECTIVE LAYER WILL BECOME
SHALLOW...DGZ WILL STILL BE CENTERED WITHIN THE CBL...ALLOWING FOR
LIGHTER FLUFFY ACCUMULATIONS TO CONTINUE.
FRI NIGHT INTO SATUURDAY...HIGH PRES RIDGE SLIPPING INTO THE W FRI
NIGHT MAY ALLOW FOR A VERY COLD NIGHT IF SKIES CLEAR. LOWERED TEMPS
WELL INTO THE SINGLE DIGITS BLO ZERO OVER THE WRN INTERIOR WHERE
THERE SHOULD BE PARTIAL CLEARING...BUT IT COULD REACH -10F OR COLDER
IF SKIES CLEAR COMPLETELY FOR A FEW HRS GIVEN FRESH SNOW COVER. SOME
LIGHT LES SHOULD CONTINUE INTO FRI NIGHT INTO SAT FOR PORTIONS OF
THE KEWEENAW AND NCNTRL WITH LIGHT CONVERGENT ONSHORE WINDS EXPECTED.
SUN THRU WED...ARCTIC AIR WILL BEGIN POOLING OVER CANADA DURING THIS
PERIOD AS RIDGE AMPLIFIES N THRU WRN ALASKA/BERING SEA INTO THE
ARCTIC. 00Z MODELS NOW ADVERTISE A SERIES OF CLIPPER SHORTWAVES
ROTATING THROUGH THE UPPER GREAT LAKES NEXT WEEK ROTATING AROUND
BROAD POLAR VORTEX ENCOMPASSING MUCH OF NRN CANADA. FIRST SHORTWAVE
MOVING THROUGH ON TUE COULD USHER IN 850 MB TEMPS COLDER THAN -20F
TUE NIGHT AS NOTED ON THE 00Z ECMWF AND THE SECOND SHORTWAVE MOVING
THROUGH WED NIGHT COULD BRING IN 850 MB TEMPS BTWN -25 AND
-30F...THE COLDEST AIR OF THE SEASON THUS FAR. WILL NEED TO KEEP A
CLOSE EYE ON MODEL TRENDS FOR NEXT WEEK AS MORE LAKE EFFECT SNOW
COULD BE IN STORE FOR NW SNOW BELTS BEGINNING TUE AND CONTINUING
INTO THU....AND WIND CHILL HEADLINES COULD BE A REAL POSSIBILITY FOR
SOME AREAS MID TO LATE WEEK.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
STEADY SNOW HAS SPREAD ACROSS CENTRAL UPPER MICHIGAN WHILE A SLIGHT
DECREASE IN SNOW COVERAGE HAS APPEARED ACROSS THE WEST WHERE
TRANSISITION TO LAKE EFFECT SNOW IS UNDERWAY. ALL LOCATIONS SHOULD
REMAIN PREDOMINATELY AT IFR CONDITIONS INTO THIS EVENING. KCMX MAY
FALL TO VLIFR AS HEAVIER LAKE EFFECT SNOW SHOWERS DECREASE VIS. BY
THIS EVENING...DRIER AIR AND A SLIGHT VEERING OF THE WINDS AT KCMX
SHOULD LIMIT HEAVIER SNOW. KIWD SHOULD ALSO SEE CONSISTENT LAKE
EFFECT SNOW THROUGH THE NIGHT BEFORE DRIER AIR MOVES IN. STEADY SNOW
AT KSAW WILL GIVE WAY TO HEAVIER SNOW DURING THE OVERNIGHT HOURS AS
LAKE ENHANCEMENT INCREASES.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/..
LOW PRESSURE DEEPENING OVER THE CENTRAL GREAT LAKES THROUGH TONIGHT
RESULTS IN WINDS OUT OF THE NORTH INCREASING TO GALES LATER TODAY
THROUGH MUCH OF FRIDAY. OTHER HAZARD OF NOTE IS HEAVY FREEZING SPRAY
THAT WILL DEVELOP OVER MOST OF THE LAKE LATE TODAY THROUGH FRIDAY
MORNING. ALL HAZARDS WILL SUBSIDE BY FRIDAY EVENING. WINDS THEN WILL
DECREASE TO LESS THAN 25 KTS THROUGH MOST OF THE WEEKEND. SOUTH
WINDS PICK UP AGAIN SUNDAY NIGHT AHEAD OF LOW PRESSURE TROUGH MOVING
ACROSS. STRONGEST WINDS WILL BE OVER THE EASTERN HALF OF THE LAKE.
WINDS BECOME NORTHWESTERLY LATER MONDAY INTO TUESDAY WITH GALE FORCE
WINDS POSSIBLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ FRIDAY FOR
MIZ010-084.
WINTER STORM WARNING UNTIL 1 PM EST /NOON CST/ FRIDAY FOR
MIZ001>003-009.
WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MIZ006.
WINTER STORM WARNING UNTIL 7 PM EST FRIDAY FOR MIZ004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM CST FRIDAY FOR MIZ011-012.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 1 PM EST FRIDAY FOR
LSZ267.
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 PM EST
FRIDAY FOR LSZ266.
GALE WARNING UNTIL 1 PM EST FRIDAY FOR LSZ244-245-263>266.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ THIS
EVENING TO 1 PM EST /NOON CST/ FRIDAY FOR LSZ162-240>244-
263-264.
GALE WARNING UNTIL 1 PM EST FRIDAY FOR LSZ248>250.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...TK
DISCUSSION...VOSS
AVIATION...TK
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1140 AM EST THU JAN 12 2012
.UPDATE...
LATEST RADAR IMAGERY IS SHOWING AN INCREASE IN AREAL COVERAGE OF
SNOWFALL ACROSS THE SOUTH CENTRAL PORTIONS OF THE CWA. GIVEN RADAR
TRENDS IN ADDITION TO SUPPORT FROM THE HRRR AND 12Z RUN OF THE LOCAL
WRF PLACING HIGHER QPF FARTHER EAST...HAVE OPTED TO PUT MENOMINEE
COUNTY IN A WINTER WEATHER ADVISORY. OBSERVATIONS ARE ALSO
INDICATING THAT SNOW TO LIQUID RATIOS ARE TRENDING SLIGHTLY HIGHER
IN THIS REGION. RESULTING SNOW TOTALS SHOULD BE 2 TO 5 INCHES...WITH
THE HIGHEST AMOUNTS ACROSS THE SOUTHERN HALF OF THE COUNTY. THE
HEAVIEST SNOW SHOULD FALL DURING THE AFTERNOON AND EVENING.
ELSEWHERE...COVERAGE OF THE SNOW REMAINS ON TRACK. A SLIGHT INCREASE
IN POPS WERE MADE FROM MUNISING TO ESCANABA FOR THIS AFTERNOON TO
ACCOUNT FOR THE CURRENT TRENDS AND SHARP EDGE OF THE PRECIPITATION
SHIELD. FATHER WEST...LAKE ENHANCEMENT ACROSS PORTIONS OF MARQUETTE
AND BARAGA COUNTY ARE HAS BECOME WELL ESTABLISHED OVER THE PAST
HOUR.
AS FOR TEMPERATURES...HIGHS HAVE LIKELY ALREADY OCCURRED ACROSS MUCH
OF THE CWA AS CONTINUOUS CAA AND THICK CLOUD COVER RESULT IN STEADY
OR SLIGHTLY DECREASING TEMPERATURES THROUGHOUT THE AFTERNOON.
PATCHY FOG ACROSS INTERIOR LOCATIONS OF THE EASTERN CWA SHOULD
DISSIPATE QUICKLY BY EARLY AFTERNOON. WINDS HAVE BECOME NORTHERLY AT
ERY AND VIS HAS INCREASED SLIGHTLY OVER THE LAST HOUR.
&&
PREV DISCUSSION...ISSUED AT 649 AM EST THU JAN 12 2012...
.DISCUSSION...
WATER VAPOR LOOP SHOWS MID-UPR TROUGH DIGGING THROUGH THE CENTRAL
PLAINS. 3H JET MAX ROUNDING THE BASE OF THIS TROUGH AND ASSOC
DIVERGENCE IN LEFT EXIT REGION OF THIS JET WILL AID IN RAPID
DEEPENING OF SFC LOW/STORM SYSTEM OVER NRN OHIO ATTM. THIS STORM
SYSTEM AND FAIRLY DEEP MOISTURE WRAPPING AROUND IT WILL HELP BRING
SIGNIFICANT LAKE ENHANCED TO PORTIONS OF WEST AND NCNTRL UPPER MI
THROUGH FRIDAY.
TODAY...PERSISTENT 800-700 MB FGEN HAS HELPED SUSTAIN OCCASIONALLY
MODERATE SNOW FM MQT INTO DICKINSON COUNTY AS NOTED ON LATEST RADAR
LOOP. MODELS SHOW FGEN PERSISTING INTO THE EARLY AFTERNOON HRS OVER
GENERALLY THIS SAME AREA SO WOULD NOT BE SURPRISED TO SEE MODERATE
SNOW CONTINUE AT TIMES. WHILE WRN COUNTIES WILL BE FARTHER AWAY FROM
SYNOPTIC FORCING FROM STORM SYSTEM OVER THE CENTRAL GREAT
LAKES...CONVERGENT NRLY FLOW AND GREATER INSTABILITY FROM COLDER
850 MB TEMPS OF -12 TO -14C...ALONG WITH FAVORABLE DENDRITIC SNOW
GROWTH AND TERRAIN ENHANCED LIFT WILL AID MODERATE TO HEAVY SNOW
ACCUMULATIONS. EXPECT 2 TO 5 INCHES OVER THESE AREAS WHERE WINTER
STORMS WARNINGS ARE ALREADY IN PLACE. ALSO LOOK FOR HIGHER TERRAIN
OF BARAGA AND WRN MQT TO SEE 3 TO 5 INCHES OF ACCUMULATION WHERE
WEAK TO MODERATE SYNOPTIC FORCING AND UPSLOPE ENHANCED LIFT SHOULD
OVERCOME MARGINAL INSTABILITY...SO WARNING STILL LOOKS GOOD FOR
THESE COUNTIES AS WELL. KEPT ADVISORY GOING FOR SRN HOUGHTON...IRON
AND DICKINSON COUNTIES THROUGH TONIGHT ALTHOUGH I AM A BIT CONCERNED
THAT SNOW COULD TAPER OFF QUICKLY TONIGHT FOR DICKINSON AND IRON AND
SOME AREAS COULD HAVE A HARD TIME REACHING ADVISORY CRITERIA (2-4
INCHES/12 HR).
ISSUED A WINTER WX ADVISORY FOR ALGER COUNTY THIS AFTERNOON THROUGH
FRIDAY AS NORTHERLY FLOW AND INCREASING INSTABILITY FROM COLDER
TEMPS MOVING IN FROM THE WEST LATER THIS AFTERNOON AND TONIGHT
SHOULD GET LAKE ENHANCED SNOW PRETTY GOOD ESPECIALLY OVER THE WRN
HALF OF THE COUNTY. LOOK FOR TOTAL ACCUMS OF 6 TO 10 INCHES THIS
AFTERNOON THROUGH FRIDAY OVER ALGER.
CANCELLED WATCH FOR NRN SCHOOLCRAFT AND OPTED NOT TO ISSUE ANY
HEADLINES FOR NRN SCHOOLCRAFT OR LUCE COUNTY AS CYCLONIC NNE FLOW
WILL NOT BE A FAVORABLE FETCH ACROSS LAKE SUPERIOR TO RECEIVE
SIGNIFICANT LES ACCUMS THROUGH FRIDAY.
TONIGHT...WITH SFC LOW/850MB LOWS WELL SE OF THE AREA OVER LAKE
HURON...POTENTIAL FOR SIGNIFICANT SYNOPTIC SNOW LOOKS LIMITED AND
MODELS GENERALLY SHOW A DIMINISHING TREND TO SNOW OVER AREAS AWAY
FROM LAKE SUPERIOR BY THIS EVENING. EXPECT NO MORE THAN AN INCH
OR TWO OF SYNOPTIC SNOW TONIGHT. CLOSE TO LAKE SUPERIOR...IT WILL BE
A FAVORABLE SETUP FOR LAKE ENHANCEMENT IN THE N WIND FAVORED AREAS.
AS COLDER AIR SPREADS IN FROM THE WEST TONIGHT THE DENDRITIC SNOW
GROWTH ZONE (DGZ) WILL FALL FIRMLY INTO THE CONVECTIVE BOUNDARY
LAYER (FM 1-3 KFT OFF FCST SNDGS) WHILE TERRAIN ENHANCED UPWARD
MOTION LAYER WILL ALSO AID LIFT IN THIS LYR. INCREASING SNOW-TO-WATER
RATIOS SHOULD RESULT IN MDT/POSSIBLY HVY SNOW ACCUMULATIONS W AND
NCNTRL. COMBINED WITH GUSTY WINDS...BLOWING AND DRIFTING SNOW WILL
ALSO ADD TO HAZARDOUS CONDITIONS ON AREA ROADS. WOULD NOT BE
SURPRISED TO SEE 6-8 INCH AMOUNTS TONIGHT WHERE TERRAIN ENHANCEMENT
IS MAXIMIZED (AROUND KIWD AND HURON MTNS).
FRIDAY...MUCH DRIER AIR WILL MAKE SHARP INROADS FROM W TO E FRI WITH
INVERSION HGTS FALLING AT OR BLO 3KFT. AS A RESULT...SNOW
INTENSITY WILL DIMINISH SIGNIFICANTLY FROM W TO E THRU THE DAY (W IN
THE MORNING...E IN THE AFTN). ALTHOUGH CONVECTIVE LAYER WILL BECOME
SHALLOW...DGZ WILL STILL BE CENTERED WITHIN THE CBL...ALLOWING FOR
LIGHTER FLUFFY ACCUMULATIONS TO CONTINUE.
FRI NIGHT INTO SATUURDAY...HIGH PRES RIDGE SLIPPING INTO THE W FRI
NIGHT MAY ALLOW FOR A VERY COLD NIGHT IF SKIES CLEAR. LOWERED TEMPS
WELL INTO THE SINGLE DIGITS BLO ZERO OVER THE WRN INTERIOR WHERE
THERE SHOULD BE PARTIAL CLEARING...BUT IT COULD REACH -10F OR COLDER
IF SKIES CLEAR COMPLETELY FOR A FEW HRS GIVEN FRESH SNOW COVER. SOME
LIGHT LES SHOULD CONTINUE INTO FRI NIGHT INTO SAT FOR PORTIONS OF
THE KEWEENAW AND NCNTRL WITH LIGHT CONVERGENT ONSHORE WINDS EXPECTED.
SUN THRU WED...ARCTIC AIR WILL BEGIN POOLING OVER CANADA DURING THIS
PERIOD AS RIDGE AMPLIFIES N THRU WRN ALASKA/BERING SEA INTO THE
ARCTIC. 00Z MODELS NOW ADVERTISE A SERIES OF CLIPPER SHORTWAVES
ROTATING THROUGH THE UPPER GREAT LAKES NEXT WEEK ROTATING AROUND
BROAD POLAR VORTEX ENCOMPASSING MUCH OF NRN CANADA. FIRST SHORTWAVE
MOVING THROUGH ON TUE COULD USHER IN 850 MB TEMPS COLDER THAN -20F
TUE NIGHT AS NOTED ON THE 00Z ECMWF AND THE SECOND SHORTWAVE MOVING
THROUGH WED NIGHT COULD BRING IN 850 MB TEMPS BTWN -25 AND
-30F...THE COLDEST AIR OF THE SEASON THUS FAR. WILL NEED TO KEEP A
CLOSE EYE ON MODEL TRENDS FOR NEXT WEEK AS MORE LAKE EFFECT SNOW
COULD BE IN STORE FOR NW SNOW BELTS BEGINNING TUE AND CONTINUING
INTO THU....AND WIND CHILL HEADLINES COULD BE A REAL POSSIBILITY FOR
SOME AREAS MID TO LATE WEEK.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
STEADY AND WIDESPREAD SNOW WL TRANSITION TO LAKE EFFECT SNOW SHOWERS
BY TONIGHT. IFR CONDITIONS WILL BE PROMINENT THROUGH THE PERIOD.
AREAS FAVORED BY NORTHERLY WINDS...KIWD AND KSAW...WILL HAVE BEST
CHANCE TO SEE PROLONGED CONDITIONS BLO ALTERNATE LANDING MINS. DUE
TO STRONG GUSTY NORTHERLY WINDS AND HEAVIER SNOW/BLOWING SNOW THERE
IS A RISK THAT CONDITIONS AT KSAW MAY NEAR AIRFIELD MINIMUMS LATE
TODAY THROUGH MUCH OF TONIGHT. CONDITIONS WILL BEGIN TO IMPROVE AT
ALL SITES BY FRIDAY AFTERNOON.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/..
LOW PRESSURE DEEPENING OVER THE CENTRAL GREAT LAKES THROUGH TONIGHT
RESULTS IN WINDS OUT OF THE NORTH INCREASING TO GALES LATER TODAY
THROUGH MUCH OF FRIDAY. OTHER HAZARD OF NOTE IS HEAVY FREEZING SPRAY
THAT WILL DEVELOP OVER MOST OF THE LAKE LATE TODAY THROUGH FRIDAY
MORNING. ALL HAZARDS WILL SUBSIDE BY FRIDAY EVENING. WINDS THEN WILL
DECREASE TO LESS THAN 25 KTS THROUGH MOST OF THE WEEKEND. SOUTH
WINDS PICK UP AGAIN SUNDAY NIGHT AHEAD OF LOW PRESSURE TROUGH MOVING
ACROSS. STRONGEST WINDS WILL BE OVER THE EASTERN HALF OF THE LAKE.
WINDS BECOME NORTHWESTERLY LATER MONDAY INTO TUESDAY WITH GALE FORCE
WINDS POSSIBLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ FRIDAY FOR
MIZ010-084.
WINTER STORM WARNING UNTIL 1 PM EST /NOON CST/ FRIDAY FOR
MIZ001>003-009.
WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MIZ006.
WINTER STORM WARNING UNTIL 7 PM EST FRIDAY FOR MIZ004-005.
WINTER WEATHER ADVISORY UNTIL 6 AM CST FRIDAY FOR MIZ011-012.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 1 PM EST FRIDAY FOR
LSZ267.
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 PM EST
FRIDAY FOR LSZ266.
GALE WARNING UNTIL 1 PM EST FRIDAY FOR LSZ244-245-263>266.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ THIS
EVENING TO 1 PM EST /NOON CST/ FRIDAY FOR LSZ162-240>244-
263-264.
GALE WARNING FROM 3 PM THIS AFTERNOON TO 1 PM EST FRIDAY FOR
LSZ248>250.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...TK
DISCUSSION...VOSS
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
717 AM CST THU JAN 12 2012
.UPDATE...
/717 AM CST THU JAN 12 2012/
MAIN BAND OF SNOW CONTINUES TO MOVE/PIVOT EAST INTO
ILLINOIS...WITH SNOW SHOWERS AND FLURRIES LEFT IN ITS WAKE. MOST
REPORTS HAVE ACCUMULATION ANYWHERE BETWEEN 0.5 AND 1.5 INCHES.
THIS WAS ENOUGH SNOW TO CAUSE MAJOR TRAFFIC ISSUES ACROSS THE
AREA...WITH NUMEROUS ACCIDENTS REPORTED.
500MB LOW HAS CLOSED OFF ACCORDING TO THE RUC AND IS ABOUT TO
ROUND THE BASE OF THE TROF ACROSS SOUTHWEST MISSOURI. SHOULD SEE
SNOW BECOME BETTER ORGANIZED AGAIN LATER THIS MORNING AND INTO THE
AFTERNOON ACROSS NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS AS
DEEP CYCLONIC FLOW DEVELOPS AS 500MB LOW MOVES ACROSS SOUTHERN
ILLINOIS. THIS AREA OF SNOW MAY REACH AS FAR SOUTH AS ST. LOUIS
METRO. OTHERWISE...SNOW SHOWERS AND FLURRIES WILL CONTINUE FOR
MUCH OF THE DAY. WILL HAVE UPDATED FORECAST OUT IN A FEW MINUTES.
CVKING
&&
.DISCUSSION...
/338 AM CST THU JAN 12 2012/
N-S BAND OF POST FRONTAL LIGHT SNOW WAS MOVING FAIRLY RAPIDLY EWD
THROUGH OUR AREA EARLY THIS MRNG...CURRENTLY MOVING INTO THE ST
LOUIS METRO AREA. THIS WAS ASSOCIATED WITH LOW-MID LEVEL
FRONTOGENESIS BEHIND THE STRONG COLD FRONT WHICH MOVED THROUGH
WED EVNG. THIS BAND OF SNOW SHOULD MOVE E OF OUR FORECAST AREA BY
LATE MRNG. ADDITIONAL SNOW...MAINLY IN THE FORM OF LIGHT SNOW
SHOWERS CAN BE EXPECTED LATE THIS MRNG AND AFTN AS AN UPPER LEVEL
LOW CUTS OFF OVER NERN KS IN THE BASE OF THE UPPER LEVEL TROUGH
EXTENDING FROM WRN MN S THROUGH ERN KS. THIS UPPER LEVEL LOW WILL
DROP E-SEWD THROUGH SRN PORTIONS OF MO AND IL TODAY. THE BEST SNOW
AMOUNTS WILL FALL LEFT OF THE TRACK OF THE UPPER LEVEL LOW. LIGHT
SNOW SHOWERS OR FLURRIES WILL LINGER OVER MAINLY IL TGT WITH
LITTLE ADDITIONAL ACCUMULATION EXPECTED TGT. TOTAL SNOW
ACCUMULATION FROM WED NIGHT AND THU SHOULD RANGE FROM ONE INCH
ACROSS PORTIONS OF SERN MO TO AROUND 2 INCHES IN THE ST LOUIS METRO
AREA TO 3 INCHES OVER PARTS OF WEST CENTRAL IL. A WINTER WEATHER
ADVISORY WILL CONTINUE TODAY OVER THE ENTIRE FORECAST AREA. STRONG
AND GUSTY NWLY SFC WINDS CAN BE EXPECTED TODAY INTO THIS EVNG DUE
TO A TIGHT SFC PRESSURE GRADIENT OVER OUR AREA BETWEEN A SFC LOW
OVER THE GREAT LAKES REGION AND THE LARGE AND STRONG SFC RIDGE
OVER THE PLAINS AND ROCKIES. BELOW NORMAL TEMPERATURES CAN BE
EXPECTED TODAY WITH THE MODELS DROPPING THE -16 DEGREE C 850 MB
ISOTHERM SEWD THROUGH MUCH OF OUR AREA TODAY BEHIND THE UPPER/SFC
LOW. PLUS LOW LEVEL CLOUD COVER AND LIGHT SNOW WILL LEAD TO LITTLE
DIURNAL RISE IN TEMPERATURES TODAY WITH HIGHS ONLY IN THE 20S.
WILL GO BELOW MOS GUIDANCE FOR THE TEMPERATURE FORECAST DUE TO
THE SNOW COVER EXPECTED. LOWS TGT AND FRI NGT SHOULD BE IN THE
TEENS...POSSIBLY IN THE SINGLE DIGITS WHERE THERE IS BETTER SNOW
COVER. THE SKY SHOULD SLOWLY CLEAR OUT LATE TGT AND FRI FROM THE
SW TO NE. TEMPERATURES WILL BE WARMER ON SAT AS THE SFC WIND BACKS
AROUND TO A SWLY DIRECTION AHEAD OF AN APPROACHING SFC TROUGH...AND
AS LOW LEVEL WAA INCREASES AHEAD OF THIS TROUGH. THE MODELS ARE
FORECASTING A NW FLOW SHORTWAVE TO DROP SEWD THROUGH ERN MO AND IL
ON SAT WITH A BAND OF LIGHT PRECIPITATION LEFT OF THE TRACK OF THE
VORT MAX ACROSS IL. IT SHOULD BE COLD ENOUGH FOR THIS PRECIPITATION
TO FALL AS SNOW. THE NAM MODEL APPEARS OVERDONE WITH THE QPF BUT
MAY BE ABLE TO PICK UP A DUSTING OF SNOW OVER THE NRN AND ERN
PORTIONS OF THE FORECAST AREA FROM THIS FAST MOVING SYSTEM.
TEMPERATURES SHOULD BE EVEN WARMER ON SUN AS THE UPPER LEVEL
HEIGHTS RISE AND THE SFC WIND BECOMES SLY. THE NEXT CHANCE OF
PRECIPITATION SHOULD BEGIN ON MON WITH TEMPERATURES WARM ENOUGH
THAT IT SHOULD FALL AS LIQUID RAIN. THE PRECIPITATION MAY CHANGE
TO SNOW BEFORE ENDING ON TUE AS COLDER AIR FILTERS SEWD INTO THE
REGION BEHIND A COLD FRONT.
GKS
&&
.AVIATION...
/507 AM CST THU JAN 12 2012/
BAND OF LIGHT TO MODERATE SNOW WILL CONTINUE TO PUSH EAST THIS
MORNING...WITH REDEVELOPMENT OF SNOW SHOWERS EXPECTED IN ITS WAKE
AS THE UPPER LOW CONTINUES TO DIG ACROSS MISSOURI AND ILLINOIS.
NORTHWEST WINDS TO REMAIN STRONG AND GUSTY...WITH BLOWING SNOW AND
REDUCED VISIBILITY. SNOW SHOWERS WILL TAPER TO FLURRIES THIS
EVENING AND SKIES WILL SCT OVERNIGHT. TOTAL ACCUMULATION OF 1 TO 3
INCHES IS EXPECTED.
SPECIFICS FOR KSTL...
BAND OF MODERATE SNOW WILL BE PULLING EAST OF THE TERMINAL AROUND
12Z...WITH LIGHT SNOW CONTINUING THIS MORNING...AND SNOW SHOWERS
INTO THE AFTERNOON. VISIBILITY WILL VARY...AND BE TIED TO BLOWING
SNOW DUE TO STRONG AND GUSTY NORTHWEST WINDS. EXPECT A TOTAL SNOW
ACCUMULATION OF 1 TO 2 INCHES. CONDITIONS TO IMPROVE THIS EVENING
WITH VFR CONDITIONS RETURNING.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR AUDRAIN
MO-BOONE MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-
GASCONADE MO-IRON MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN
MO-MADISON MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
OSAGE MO-PIKE MO-RALLS MO-REYNOLDS MO-SHELBY MO-ST. CHARLES
MO-ST. FRANCOIS MO-ST. LOUIS CITY MO-ST. LOUIS MO-STE.
GENEVIEVE MO-WARREN MO-WASHINGTON MO.
IL...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR ADAMS IL-
BOND IL-BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-
JERSEY IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-
MONTGOMERY IL-PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON
IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
521 PM CST FRI JAN 13 2012
.AVIATION...
00Z TAFS FOR KOFK...KOMA AND KLNK.
CLIPPER-TYPE SYSTEM SHOULD MOVE QUICKLY INTO NERN NEBRASKA AROUND
14/06Z AND THEN INTO SERN MO BY 14/18Z. THIS SYSTEM WILL BRING A
SHIFT TO GUSTY NORTHWEST WINDS LATE TONIGHT/EARLY SATURDAY...
AND POSSIBLY A PERIOD OF LOWER CLOUDS AND SCATTERED SNOW SHOWERS.
SNOW CHCS APPEARED SOMEWHAT BETTER AT KOFK AND KOMA. SURFACE WINDS
SHOULD RELAX SATURDAY AFTERNOON BEFORE TURNING TO S/SW IN THE
EVENING AHEAD OF YET ANOTHER SYSTEM.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 342 PM CST FRI JAN 13 2012/
SHORT TERM...TONIGHT THROUGH MONDAY.
THE PRIMARY CONCERNS IN THE SHORT TERM WILL THE HOW FAR SOUTHWEST
TO CARRY THE LIGHT SNOW AND FLURRIES OVERNIGHT AND EARLY
SATURDAY...TEMPERATURES SATURDAY AND SUNDAY...HOW FAR NORTH WILL
THE LIGHT RAIN AND DRIZZLE MAKE IT MONDAY MORNING...AND LIGHT SNOW
MOVING IN FROM THE WEST MONDAY.
AT 18Z...LIGHT SNOW RETURNS HAVE SPREAD INTO PARTS OF MT AND BY
20Z GGW WAS DOWN TO 1/2SM IN SNOW. SINCE THE OPERATIONAL MODELS
WERE ALL DRY AT THAT TIME IN MT...NOT REAL CONFIDENT IN HOW THEY
ARE HANDLING THIS SYSTEM. THE SHORTWAVE TROF OVER THE WRN DAKOTAS
IS FORECAST TO QUICKLY DROP SOUTHEAST OVERNIGHT INTO MISSOURI BY
12Z. THIS WITH WAA...UPWARD VERTICAL MOTION WITH THE WAVE...AND
POTENTIAL VORTICITY ADVECTION. THE 12Z/18Z CONTINUED DRY EXCEPT
FOR HARRISON CO IN IOWA. THE GFS HAS SOME LIGHT PRECIPITATION
MAKING IT INTO NORTHEAST NEB WHILE THE 00Z/12 EC/12Z 4KM WRF AND
THE LATEST HRRR ARE A BIT STRONGER WITH THE WAVE IN GENERATING
LIGHT SNOW FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. ALTHOUGH
THERE ARE QUITE A FEW RETURNS SHOWING UP AT 21Z...SFC REPORTS ARE
STILL SPARSE IN REPORTING THE SNOW. LOOKING AT THE FORCING...
SATURATION...AND COLDEST TEMPS HAVE INCLUDED SOME SLIGHT CHC TO
CHC POPS OVER ESPECIALLY THE NORTHEASTERN THIRD OF THE CWA. AT
THIS TIME ONLY ADDED SOME VERY LIGHT AMOUNTS TO THE NORTHEAST.
ALTHOUGH SURFACE DEWPOINTS ARE VERY LOW (BELOW ZERO WRN IA AND THE
ALONG THE MISSOURI RIVER)...LOOK FOR THEM TO INCREASE OVERNIGHT
INTO THE TEENS AND 20S. WITH A SURFACE LOW TRACKING ACROSS THE
AREA OVERNIGHT...TEMPERATURES WILL BE TRICKY...FALLING OFF QUICKLY
TONIGHT IN WRN IOWA...BUT BEING HELD UP ACRS THE WRN CWA.
MID LEVEL RIDGING WILL BUILD IN FOR THE WEEKEND. WARMER
TEMPERATURES ARE FORECAST FOR WEEKEND WITH 50S FOR SUNDAY. THE
NEXT COLD FRONT MOVES THROUGH OVERNIGHT SUNDAY AND LOW CLOUDS AND
SOME DRIZZLE COULD DEVELOP IN SOUTHWEST IOWA. COLDER AIR WILL
RETURN FOR MONDAY WITH LIGHT SNOW DEVELOPING OVER SOUTH DAKOTA AND
WESTERN AND CENTRAL NEBRASKA. THIS LIGHT SNOW COULD START TO MAKE
IT INTO PARTS OF THE WESTERN FORECAST AREA BY DAY/S END.
ZAPOTOCNY
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
MODELS CERTAINLY DIVERGE REGARDING THE AMOUNT AND INTENSITY OF COLD
AIR PLUNGING INTO THE PLAINS BY MID TO LATE WEEK. THE OPERATIONAL
GFS HAS REMAINED THE COLDEST OF THE MEDIUM RANGE MODELS...WITH ECMWF
THE WARMEST. GFS ENSEMBLE MEMBERS OFFER NO HELP AS THE SPREAD IS
WIDE HERE TOO. IN FACT...THE 00Z ENSEMBLE TEMPERATURES FOR THURSDAY
HIGHS RANGED FROM 21 TO 49 AT OMAHA.
LEADING UP TO THIS TIME PERIOD...A SIMILAR EVOLUTION OF THE UPPER
FLOW PATTERN IS NOTED BY GFS/ECMWF. BOTH SHOW A BROAD TROUGH OVER
THE CENTER OF THE COUNTRY WITH A SHORTWAVE MOVING THROUGH NEBRASKA
AND IOWA MONDAY NIGHT AND TUESDAY. AND BOTH MODELS BREAK OUT LIGHT
SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS NORTHERN NEBRASKA INTO
NORTHERN IOWA. OUR CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST
MONDAY NIGHT...SO LEFT THAT UNCHANGED. HOWEVER...SLIGHTLY SLOWER
ECMWF KEEPS SNOW IN FOR TUESDAY. IF THIS OCCURS IT SHOULD ONLY
AFFECT OUR EAST AND SHOULD BE ENDING QUICKLY IN THE MORNING.
THEN UPPER PATTERN BEGINS TO FLATTEN OUT SOME...WITH NORTHWEST FLOW
THE CONSENSUS FOR WEDNESDAY. HIGHS IN THE 20S TUESDAY IN COOL
ADVECTION REGIME WILL WARM INTO THE 30S WEDNESDAY.
THURSDAY IS THE BIG QUESTION MARK AS THE GFS CONTINUES TO SHOW
STRONG BAROCLINIC ZONE DROPPING THROUGH THE CWA WHILE ECMWF KEEPS
BRUNT OF COLD AIR TO OUR NORTHEAST. DURING NORMAL WINTERS WOULD
EXPECT THE GFS AND COLD AIR TO WIN OUT...BUT THIS HAS BEEN ANYTHING
BUT A NORMAL WINTER. WE HAVE SEEN THESE SCENARIOS ADVERTISED AT DAYS
6 AND 7 BEFORE...AND TRENDING TOWARD WARMER SOLUTIONS HAS BEEN BEST.
ESPECIALLY WITH LIMITED SNOW COVER TO OUR NORTH. BOTH SIDES OF THE
ARGUMENT HAVE MERIT...SO TO STAY CONSISTENT WITH CURRENT
FORECAST...SURROUNDING OFFICES AND WIDELY DIVERGENT MODELS...WILL
HAVE TO KEEP TEMPERATURES CLOSE TO WHAT WE CURRENTLY HAVE GOING WITH
HIGHS IN THE 20S AND LOWER 30S. WHATEVER THE CASE...EXPECT A LITTLE
WARMER CONDITIONS ON FRIDAY AS RETURN FLOW SETS UP. MAY ALSO SEE
SOME LIGHT SNOW WITH THIS SCENARIO.
DERGAN
AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL SITES THROUGH THE
TAF PERIOD. A FRONTAL BOUNDARY WILL APPROACH THE CWA THIS
AFTERNOON...BRINGING WINDS AROUND TO THE SOUTHEAST AHEAD OF THE
FRONT. OVERNIGHT...WINDS BEHIND THE FRONT ARE EXPECTED TO
INCREASE AND SWITCH TO THE NORTHWEST.
ROUKE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS BUFFALO NY
103 AM EST THU JAN 12 2012
.SYNOPSIS...
A COMPLEX STORM SYSTEM APPROACHING FROM THE TENNESSEE VALLEY WILL
SEND RAIN...AND A WINTRY MIX FOR THE EASTERN LAKE ONTARIO
REGION...ACROSS THE EASTERN GREAT LAKES OVERNIGHT AND INTO THURSDAY
MORNING. A BRIEF LULL IN THE PRECIPITATION ACROSS MUCH OF THE REGION
LATER TOMORROW AS THE RAIN AND WINTERY MIX PUSHES NORTHWARD BEFORE
ADDITIONAL RAIN CHANGING TO SNOW SWEEPS IN FROM THE WEST OVERNIGHT.
WINDS WILL BECOME BLUSTERY FRIDAY WITH WIDESPREAD
SNOWFALL...BECOMING MORE CONCENTRATED DOWNWIND OF BOTH OF THE
LAKES...WITH THE POTENTIAL FOR THIS LAKE EFFECT SNOW TO CONTINUE
INTO SATURDAY BEFORE DIMINISHING.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 06Z...RAIN HAS LIFTED ACROSS ALL OF WESTERN NEW YORK AND
IS JUST NOW STARTING EAST OF LAKE ONTARIO AS A WINTRY MIX. WHILE
TEMPERATURES ARE SAFELY ABOVE FREEZING ACROSS THE WESTERN COUNTIES...
THE SAME CANNOT BE SAID FROM THE TUG HILL NORTH AND EAST.
A WAVY FRONTAL BOUNDARY STRETCHED ACROSS THE NORTH COUNTRY AS OF 06Z
WITH COLD AIR DAMMING EVIDENT ON A SFC ANALYSES FROM WATERTOWN
ACROSS THE THOUSAND ISLANDS TO THE ST LAWRENCE VALLEY. TEMPERATURES
NORTH OF THE BOUNDARY ARE IN THE TEENS AND 20S...AND WITH A
NORTHEAST LOW LEVEL FLOW HOLDING IN PLACE THROUGH THE NIGHT AND
LIKELY THROUGH A LARGE PART OF THURSDAY...A PROLONGED MIXED BAG OF
FREEZING RAIN...SLEET AND EVEN A BIT OF WET SNOW WILL FALL.
LIKE THE PREVIOUS SHIFT...AM CONCERNED ABOUT WHETHER ENOUGH ICE
COULD ACCUMULATE TO WARRANT A WARNING VERSUS THE CURRENT WINTER
WEATHER ADVISORY. QPF AMOUNTS WILL AVERAGE ABOUT A HALF INCH THROUGH
MIDDAY THURSDAY...BUT ENOUGH OF THE PCPN SHOULD FALL AS SLEET TO
KEEP FREEZING RAIN AMOUNTS BELOW WARNING CRITERIA. WILL HOLD ONTO
THE ADVISORY FOR JEFFERSON AND LEWIS COUNTIES FOR NOW...ALTHOUGH IT
MAY NEED TO BE EXTENDED DEEPER TO THURSDAY EVENING. AT THIS POINT...
AM LEANING TOWARDS DROPPING THE ADVISORY WITH THE UPCOMING EARLY
MONRING PACKAGE FOR OSWEGO COUNTY WHERE COLD AIR DAMMING IS NOT AN
ISSUE.
THE RAIN ACROSS THE REGION TYHROUGH DAYBREAK WILL BE THE RESULT OF
BEING UNDER THE RR ENTRANCE REGION OF A 120 KT JET OVER QUEBEC AND
CONVERGENCE FOUND ALONG A 50KT 900 HPA JET. DEEPEN MOISTURE IN THE
LOWER LEVELS...WITH PWATS RISING TO NEAR +2SD OVERNIGHT WILL FUEL
THE PRECIPITATION THROUGH THE OVERNIGHT. EXPECT BASIN QPF AVERAGES
TO BE AROUND 0.40 TO 0.75 INCHES OVERNIGHT WITH THE HIGHEST TOTALS
TOWARDS THE EAST...CLOSER TO THE CORE OF THE LLJ.
ON THURSDAY...AN OCCLUDED FRONT FROM THE PRIMARY LOW OVER OHIO WILL
PUSH NORTHWARD TOWARDS THE SOUTHERN SHORELINE OF LAKE ONTARIO BY
AFTERNOON. DRIER AIR IN THE MID LEVELS (700MB AS PER THE GFS) WILL
LIFT ACROSS THE REGION DURING THE DAY THURSDAY...SHUTTING DOWN THE
STEADY RAIN AND MAKING THE PCPN MORE SPOTTY IN NATURE...WITH LIGHT
RAIN SHOWERS OR DRIZZLE BEING EXPERIENCED. THE EXCEPTION WILL COME
ALONG THE LAKE ONTARIO SHORELINE AND ACROSS THE NORTH COUNTRY WHERE
THIS REGION WILL REMAIN NORTH OF THE SFC BOUNDARY.
TEMPERATURES FOR THE REST OF THE OVERNIGHT...TEMPERATURES WILL
REMAIN ABOVE FREEZING ACROSS THE WESTERN COUNTIES WHILE SUB FREEZING
CONDITIONS WILL BE FOUND NORTH AND EST OF THE TUG. FOR THURSDAY...
MERCURY READINGS WILL GENERALLY BE IN THE 40S WITH THE COLDER AIR
NORTH OF THE TUG FINALLY BEING MODIFIED TOWARDS EVENING.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
A VERY COMPLEX WEATHER SCENARIO WILL BE UNFOLDING DURING THIS PERIOD
AS THE SOUTHERN STREAM LOW LIFTING INTO THE NORTHEAST CONUS IS
INTERCEPTED BY A DEEP UPPER LEVEL TROUGH DROPPING ACROSS THE
NORTHERN PLAINS INTO THE GREAT LAKES WITH THE RESULT BEING A DOUBLE
SURFACE LOW STRUCTURE ACROSS THE REGION. THE DOMINANT LOW WILL BE
ACROSS THE GREAT LAKES...WHILE THE SECONDARY WEAKER LOW RESIDES OFF
THE SOUTHERN NEW ENGLAND COAST AT THE START OF THE PERIOD. THE MAIN
OCCLUSION WILL BE NORTH OF THE AREA WHICH SHOULD HAVE WESTERN AND
CENTRAL NEW YORK IN A RELATIVE LULL IN PRECIPITATION AT THE BEGIN OF
THURSDAY NIGHT. LATER THURSDAY NIGHT THERE WILL BE RAPID CYCLONE
INTENSIFICATION BOTH AT THE SURFACE AND ALOFT WHICH WILL CORRESPOND
WITH INCREASE LAKE ENHANCEMENT OFF LAKE ERIE AND INCREASING ATLANTIC
MOISTURE INFLOW...WHICH SHOULD POINT TO THE EXPANSION OF SNOW OR
MIXED PRECIPITATION ACROSS EASTERN SECTION ALONG THE INTENSIFYING
BAROCLINIC ZONE UNDERNEATH THE DEEPENING COUPLED JET CIRCULATION
ALOFT. THE DEEPENING SURFACE LOW WILL BE LIFTING THROUGH SAINT
LAWRENCE VALLEY FRIDAY...WITH THE SUGGESTION OF A TROWAL FEATURE
DEVELOPING IN ASSOCIATION WITH THE MID LEVEL DEFORMATION ZONE.
ORIENTATION OF THIS FEATURE DIFFERS FROM MODEL TO MODEL MAKING THE
PLACEMENT OF POTENTIAL HEAVY SNOWFALL AXIS FRIDAY RATHER DIFFICULT.
STILL PLENTY OF UNCERTAINTY TO HOW THE SYNOPTIC PORTION OF THIS
SYSTEM WILL PLAY OUT PLACING RELATIVE LOW CONFIDENCE IN SNOWFALL
FORECAST FOR THE THURSDAY NIGHT AND FRIDAY TIME FRAME. WE ARE LIKELY
LOOKING AT A GENERAL ACCUMULATING SNOW SEVERAL INCHES...ALTHOUGH
SIGNIFICANT AMOUNTS TO THE LEE OF THE LAKES WILL BE POSSIBLE...
ESPECIALLY IF LAKE ENHANCEMENT CAN GET GOING EARLY ENOUGH.
STARTING LATE FRIDAY...THE LAKE EFFECT SNOW WILL BEGIN IN EARNEST AS
THE FLOW VEERS TO WEST...THEN TO WEST NORTHWEST AND 850 MB
TEMPERATURES DROP INTO THE NEGATIVE LOWER TEENS CELSIUS. PLENTY OF
SYNOPTIC SCALE MOISTURE WILL BE IN PLACE ALLOWING IMPRESSIVE DEPTH
OF FAVORABLE DENDRITIC SNOW GROWTH REGION TO INTERSECT OMEGA
MAXIMUM. THIS WOULD SUGGEST THE POTENTIAL FOR HEAVY LAKE SNOWS IN
THE TRADITIONAL WEST NORTHWEST FLOW REGIONS SOUTH OF BUFFALO AND
WATERTOWN. STRONG WIND FIELDS MAY HAMPER THE ORGANIZED OF PROLONGED
LAKE BANDS...BUT THIS CAN BE ADDRESSED IN LATER FORECAST ISSUANCES.
LAKE EFFECT SETUP STILL FAR ENOUGH IN ADVANCE TO KEEP HEADLINES OUT
OF FORECAST FOR NOW.
WINDS MAY BECOME AN ISSUE FRIDAY...ESPECIALLY DOWNWIND OF THE LAKES
WITH BUFKIT MOMENTUM TRANSFER SCHEMES SUGGESTING A PERIOD OF SUSTAIN
WINDS OVER 25 KNOTS AND GUSTS OVER 40 KNOTS WHICH MAY PROMPT
HEADLINES IN LATER FORECASTS AS WELL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
BY THE END OF THE WEEKEND...AIR MASS STILL LOOKS PLENTY COLD ENOUGH
WITH 850 MB TEMPERATURES IN THE NEGATIVE MID TEENS CELSIUS TO
MAINTAIN THE POTENTIAL FOR LINGERING LAKE SNOWS SOUTHEAST OF THE
LAKES. SOME SUGGESTION THAT INVERSION HEIGHTS WILL BE LOWERING...
THEREFORE THE INTENSITY OF THE LAKE SNOWS IS IN QUESTION AT THIS
POINT. LAKE ACTIVITY WILL SHUT DOWN COMPLETELY SUNDAY NIGHT AND
MONDAY AS BROAD RIDGE PUSHES ACROSS THE REGION. THE RIDGE LOOKS TO
SLIDE EAST MONDAY NIGHT AND A STRONG WARM AIR ADVECTION PATTERN SETS
UP BEHIND IT AND AHEAD OF AN APPROACHING ELONGATED COLD FRONT.
INCREASE LOW LEVEL MOISTURE INFLOW AHEAD OF THIS FRONT WILL INCREASE
THE THREAT FOR SNOW IN THE MONDAY NIGHT AND TUESDAY TIME FRAME...
WITH THE ADDED LAKE COMPONENT AS COLDER AIR SPILLS BACK ACROSS THE
LOWER LAKES. AIR MASS LOOKS COLD ENOUGH WITH ENOUGH SYNOPTIC SCALE
MOISTURE TO REGENERATE WEST NORTHWEST FLOW LAKE SNOWS FOR TUESDAY
NIGHT AND WEDNESDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
RAIN WILL BE FOUND ACROSS ALL OF WESTERN NEW YORK THROUGH THE
OVERNIGHT WITH CIGS DETERIORATING TO IFR LEVELS. FOR THE EASTERN
LAKE ONTARIO REGION...LOW LEVEL COLD AIR BEING FED SOUTH FROM THE ST
LAWRENCE VALLEY WILL RESULT IN A MIXED BAG OF WINTRY PCPN INCLUDING
SOME ICE FOR KART. SIGNIFICNAT ICING WILL BE POSSIBLE FOR THIS SITE
AND COULD SERIOUSLY AFFECT COMMERCIAL AIR TRAFFIC AND LOCAL
OPERATIONS.
IFR CIGS SHOULD BE IN PLACE FOR THE WESTERN NY TAF SITES BY THURSDAY
DAYBREAK WHILE MVFR CIGS WILL MOVE ACROSS KART. THESE CIGS WILL BE
WIDESPREAD THROUGH EARLY THURSDAY AFTERNOON BEFORE LOWER ELEVATIONS
POSSIBLY IMPROVE TO MVFR LATER IN THE DAY. HIGHER TERRAIN SHOULD
STAY LOCKED INTO IFR THROUGH THE AFTERNOON WITH STRATUS NEAR THE
HILLTOPS IN SOME LOCATIONS.
OUTLOOK...
THURSDAY NIGHT THROUGH FRIDAY...MVFR TO IFR WITH RAIN CHANGING TO
SNOW.
FRIDAY NIGHT AND SATURDAY MVFR IN CHC SNOW...HEAVIER SNOW LIKELY
SOUTHEAST OF THE LAKES WITH IFR CONDITIONS.
SUNDAY...MVFR TO VFR IN LINGERING SNOW SHOWERS.
MONDAY...MAINLY VFR.
&&
.MARINE...
AS EASTERLY WINDS INCREASE IN SPEED OVERNIGHT WINDS AND WAVES WILL
RISE ABOVE SCA CRITERIA...AND WILL ISSUE A SMALL CRAFT FOR THE
WESTERN HALF OF LAKE ONTARIO FOR LATE THIS EVENING THROUGH
THURSDAY.
MUCH COLDER AIR WILL SURGE ACROSS THE RELATIVELY WARM LAKE WATERS
THURSDAY NIGHT AND FRIDAY. THIS WILL PROMOTE STRONG MIXING WITHIN THE
LOWER LEVELS OF THE ATMOSPHERE...RESULTING IN A CHANCE FOR GALE
FORCE WINDS THURSDAY NIGHT AND FRIDAY. WILL ISSUE A GALE WATCH FOR
LAKE ERIE STARTING LATE THURSDAY NIGHT THROUGH FRIDAY. WINDS ON LAKE
ONTARIO WILL INCREASE LATER IN THE DAY FRIDAY...WITH WINDS NEARING
GALE FORCE LATE FRIDAY AFTERNOON.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
NYZ006>008.
MARINE...GALE WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR
LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON
FOR LOZ042-043.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...HITCHCOCK/THOMAS
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...HITCHCOCK/RSH
MARINE...THOMAS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1235 AM EST THU JAN 12 2012
.SYNOPSIS...
A STORM SYSTEM WILL BRING PRECIPITATION TONIGHT INTO THURSDAY.
EAST OF INTERSTATE 81...ESPECIALLY AT HIGHER ELEVATIONS...THE
PRECIPITATION MAY BEGIN AS A WINTRY MIX OF FREEZING
RAIN...SLEET...AND SNOW. THE REMAINDER OF THE REGION WILL
GENERALLY HAVE JUST A COLD RAIN. HOWEVER...A COLD FRONT WILL SWEEP
THROUGH LATE THURSDAY NIGHT INTO FRIDAY MORNING...RESULTING IN
SNOW SHOWERS DURING THE DAY FRIDAY. COURTESY OF LAKE EFFECT...SNOW
SHOWERS CONTINUE INTO SATURDAY FOR MUCH OF THE REGION.
&&
.NEAR TERM /THROUGH TODAY/...
1030 PM UPDATE...NO CHANGES TO THE PREVIOUS FORECAST. UPDATE
EARLIER TO REMOVE SNOWFALL AMOUNTS LOOKS TO BE ON TRACK WITH JUST
A FEW REPORTS OF A FEW FLAKES AT THE ONSET. WE ARE MOSTLY SEEING SLEET
OR RAIN...WITH SOME POCKETS OF FREEZING RAIN. AS THE
PRECIPITATION MOVES FARTHER NORTH AND EAST AND ENCOUNTERS SOME
COLDER SURFACE TEMPS AND LOWER DEWPOINTS...FREEZING RAIN WILL
BECOME MORE LIKELY AND THE ADVISORY CURRENTLY IN PLACE COVERS
THIS. I WAS TEMPTED TO DROP MADISON...CHENANGO...PIKE...AND WAYNE
COUNTIES FROM THE ADVISORY WITH MOST MESONET SITES SHOWING TEMPS
IN THE MID 30S. DECIDED TO HOLD OFF BECAUSE WE HAVE GOTTEN A FEW
REPORTS OF FREEZING RAIN BUT THEY HAVE BEEN CONFINED TO ELEVATIONS
CLOSER TO 2000 FEET IN THESE AREAS. WITH THE UPDATE TO THE
ADVISORY...TRIED TO STRESS HIGHER ELEVATIONS HERE FOR THE FREEZING
RAIN POTENTIAL.
FARTHER NORTH AND EAST IN OUR NORMALLY COLDER SPOTS OF
ONEIDA...OTSEGO...DELAWARE AND SULLIVAN COUNTIES...FREEZING RAIN
POTENTIAL IS MUCH HIGHER AND I REMOVED ANY HIGHER ELEVATION
WORDING BECAUSE IT WILL BE MORE WIDESPREAD HERE AND NOT JUST
CONFINED TO THE HIGHEST TERRAIN. A GOOD EXAMPLE IS MONTICELLO
WHICH HAS DROPPED FROM 36 TO 32 AND IS PROBABLY SEEING SOME
FREEZING RAIN ATTM. THE PREVIOUS AFD IS BELOW...
730 PM
UPDATE...OVERALL FORECAST EVOLUTION IS IN GOOD SHAPE.
PRECIPITATION IS ADVANCING ACROSS THE SOUTHERN THIRD OF THE CWA AS
WE SPEAK. PREFER THE NAM/RUC FORECAST SOUNDINGS WHICH SHOW THE
PRECIPITATION STARTING OFF MOSTLY AS ALL RAIN IN THE LOWER
ELEVATIONS...WITH A MIX OF ANYTHING FROM RAIN TO SLEET OR EVEN A
FEW SNOWFLAKES ABOVE 1200 FEET. TAMDAR SOUNDINGS OUT OF SYRACUSE
SHOW THIS NICELY WITH PLENTY OF DRY AIR IN THE MID LEVELS ALLOWING
FOR SOME QUICK WET BULBING...BEFORE OUR WARM NOSE PUNCHES IN
AROUND 850 MB. THIS PUNCH OF WARMER AIR WILL TRANSITION MOST OF
THE AREA TO PLAIN RAIN. THE EXCEPTION WILL BE FARTHER EAST AND
NORTH...WHERE WE HAD ADVISORIES IN PLACE...WHERE THE MIX OF
SLEET/SNOW...AND EVEN SOME FREEZING RAIN WILL LINGER MUCH LONGER.
MAIN ADJUSTMENT TO THIS PACKAGE IS TO LOWER SNOWFALL AMOUNTS.
WHILE SOME SNOW IS POSSIBLE NEAR THE ONSET AND SHORTLY
THEREAFTER...FEEL THE WARM NOSE DEPICTED ON THE RUC AND NAM WILL
BE ENOUGH TO HELP US MIX WITH SLEET QUICKLY...THUS CUTTING DOWN
SNOWFALL AMOUNTS. AT THIS POINT SEE NOTHING MORE THAN A COATING OF
SNOWFALL OVER THE FAR EAST...WITH OUR ADVISORIES JUSTIFIED BY A
COMBINATION OF SLEET AND ESPECIALLY FREEZING RAIN.
AFTER 07Z ENOUGH WARM AIR ALOFT WILL MOVE INTO THE AREA THAT IT
WILL BE JUST A RAIN OR FREEZING RAIN SITUATION...WITH ALL THE
EMPHASIS SHIFTING TO OUR SURFACE TEMPS. OUR NORMALLY COLDER SPOTS
FROM NORTHERN OTSEGO COUNTY INTO THE MOHAWK VALLEY REMAIN AT THE
HIGHEST RISK FOR A PROLONGED PERIOD OF LIGHT FREEZING RAIN. THIS
IS WELL SUPPORTED BY OBS IN THE CENTRAL MOHAWK VALLEY THAT ARE
ALREADY BELOW FREEZING...WITH DEW-POINTS IN THE LOWER TO MIDDLE
20S.
LOOK FOR OUR NEXT UPDATE AROUND 10 PM. IF WE CONTINUE TO SEE TEMPS
ABOVE FREEZING IN NORTHERN PA...WE MAY BE ABLE TO TRIM BACK OUR
ADVISORY FROM SOUTH TO NORTH.
415 PM
UPDATE...TREND FOR A WARMER INCIPIENT BOUNDARY LAYER CONTINUES IN
THE MODELS...AS SYSTEM MOVES IN TONIGHT. THUS I DO NOT SEE A NEED
FOR ANY FURTHER EXPANSION OF CURRENT WINTER WEATHER
ADVISORY...WHICH INCLUDES COUNTIES EAST OF INTERSTATE 81. FOR
COUNTIES ALONG AND WEST OF INTERSTATE 81...HIGH CONFIDENCE NOW
THAT PRECIPITATION TYPE WILL BE ALL RAIN...WITH PERHAPS ONLY A
LITTLE BRIEF SLEET BUT WITH TEMPERATURES STAYING ABOVE FREEZING.
AND OF THE WINTER WEATHER ADVISORY COUNTIES...TRANSITION TO PLAIN
RAIN WILL OCCUR EARLY FOR ALL BUT ONEIDA/DELAWARE/OTSEGO...SO I
MOVED UP THE END TIME FOR THOSE ZONES TO 6 AM. FOR THE EARLIER
ENDING ZONES...ICE AND SNOW ACCUMULATIONS LOOK TO BE FAIRLY LIGHT
AND MAINLY AT HIGHER ELEVATIONS. MANY VALLEY LOCATIONS MAY GET
THROUGH WITH ONLY PLAIN RAIN OR A LITTLE LIGHT SLEET.
COLD AIR WILL LINGER LONGER IN THE NORTHEASTERN ZONES COURTESY OF
COLD AIR DAMMING...SO WINTRY MIX WILL LAST INTO THE MORNING. WE
WILL HAVE TO WATCH CLOSELY FOR ICE ACCUMULATIONS IN EXCESS OF A
QUARTER INCH...IN PARTICULAR TOWARDS THE MOHAWK VALLEY/SOUTHERN
TUG HILL PLATEAU...SHOULD THE COLD AIR TAKE LONG TO SCOUR OUT.
SNOW ACCUMULATIONS MEANWHILE WILL BE OF HIGH WATER
CONTENT...GENERALLY 1 TO 3 INCHES AND MAINLY AT HIGHER ELEVATIONS.
WHATEVER THE TYPE...FOR THE AREA IN GENERAL RAW PRECIPITATION
AMOUNTS WILL RANGE FROM A HALF INCH OR SO IN THE WEST-
NORTHWEST...TO ALMOST AN INCH IN THE SOUTHEAST. AFTER A BRIEF DIP
IN TEMPERATURES EARLY THIS EVENING...LOOKING FOR STEADY TO
SLOWLY RISING TEMPERATURES OVERNIGHT. FINGER LAKES...SOUTHERN
TIER OF NY...AND MOST OF NORTHEAST PA WILL EVENTUALLY GET INTO
THE 40S THURSDAY.
DEEPER MOISTURE EXITS WITH THE OCCLUDED FRONT MIDDAY
THURSDAY...LEAVING LIGHT SHOWERS OR PERHAPS DRIZZLE IN THE
AFTERNOON TO EVENING. BOUNDARY LAYER WILL BE SLOW TO COOL THURSDAY
NIGHT...UNTIL ARRIVAL OF STRONG NEGATIVELY TILTED COLD FRONT
TOWARDS DAWN FRIDAY. SO CHANGEOVER OF ANY REMAINING LIGHT RAIN
SHOWERS TO SNOW...WILL BE GRADUAL.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
UPDATED AS OF 4 PM WED... MODEL CONSENSUS IS FAIRLY GOOD ON SYSTEM
EVOLUTION THIS PD.
A STG COLD FRONT IS SLATED TO CROSS THE FA FROM SW TO NE FRI
AM...GENERALLY IN THE 12-15Z TIME FRAME. QG FORCING IS PRETTY POTENT
WITH THIS FRNT...AS A HEALTHY UPPER-LVL WAVE ACCOMPANIES IT...SO
MOST SXNS SHOULD SEE SHRA/SHSN WITH THE FROPA.
INITIALLY...THE DEEP-LYRD FLOW IS PROGGED TO BE SWLY FRI AFTN
POST-FROPA...SO AS THE LAKES BEGIN TO FIRST RESPOND TO THE INCOMING
COLD AIR...THE BRUNT OF THE LES SHOULD STAY N AND W OF THE
CWA...WITH JUST SCTD -SHSN/FLRYS ANTICIPATED IN CNY/NRN TIER PA.
WINDS SHOULD BE STG AND GUSTY FRI AFTN...WITH DECENT ISALLOBARIC
FORCING AND GOOD MOMENTUM TRANSFER CONDITIONS AT PLAY. ADVSY LVL
WIND GUSTS ARE NOT OUT OF THE QUESTION (35-45 KT)...SPCLY OUR
NRN/WRN ZNS...AND LATER SHIFTS WILL BE TAKING A CLOSER LOOK AT THIS.
FRI NGT AND SAT...AS A SECONDARY SFC TROUGH PUSHES THROUGH...AND
ADDITIONAL UPPER-LVL WAVES TRAVERSE THE RGN...THE BLYR FLOW SHOULD
VEER MORE INTO A 280-300 VECTOR WITH TIME. THIS SHOULD STEER MORE
PERSISTENT LES INTO OUR FA.
THE BEST OPPORTUNITY FOR MORE SIG LES MAY BE RESTRICTED TO A
RELATIVELY NARROW WINDOW FRI NGT...WHEN THE BEST COMBO OF CYCLONIC
FLOW AND DEEPER MOIST/PSBL MULTI-LK INFLUENCE EXISTS. HOWEVER...THE
DETRACTING ELEMENTS OF TRANSITIONAL FLOW AND TERRESTRIAL INSTAB FRI
EVE ALSO SEEM TO BE THERE. TIME WILL TELL ON HOW THIS ALL SHAKES
OUT...BUT WE DO HAVE LIKELY POPS FOR SHSN FROM LATER FRI AFTN INTO
EARLY SAT ACROSS MANY OF OUR NRN ZNS.
AS WE HEAD THRU THE DAY SAT...THE INVERSION SHOULD LWR
SUBSTANTIALLY...WITH THE MOIST SUPPLY ALSO WANING. THUS...MORE
PERSISTENT SHSN SHOULD DIMINISH TO SCTD -SHSN/FLRYS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
3 PM UPDATE...
SATURDAY NIGHT/SUNDAY...850 TEMPS OF -16C TO -18C AND A NORTHWEST
FLOW WILL BE FAVORABLE FACTORS FOR LAKE EFFECT SNOW DURING THIS
TIME BUT A LOW INVERSION (4KFT SATURDAY NIGHT THEN LOWERING
SUNDAY) ALONG WITH DRY AIR WILL INHIBIT MUCH FROM HAPPENING. STILL
WITH COLD AIR IN PLACE EXPECT A FEW FLURRIES OR A BRIEF SNOW
SHOWER ESPECIALLY FROM SYRACUSE DOWN THROUGH THE CORTLAND AREA ON
A 320 FLOW.
SUNDAY NIGHT/MONDAY....HIGH PRESSURE BUILDING SOUTH ACROSS THE
AREA WILL KEEP THIS PERIOD DRY AND QUIET. WITH A BETTER SHOT AT A
CLEAR SKY SUNDAY NIGHT...MORNING LOWS MONDAY WILL BE IN THE SINGLE
DIGITS FOR MOST OF THE AREA WITH READINGS BELOW ZERO OVER THE FAR
EAST AND NORTH.
TUESDAY/WEDNESDAY....AN AREA OF LOW PRESSURE MOVING THROUGH THE
NORTHERN GREAT LAKES STILL LOOKS TO BRING US OUR NEXT SHOT AT
SIGNIFICANT PRECIPITATION. BOTH THE EURO AND GFS ARE PRETTY SIMILAR
WITH THE TRACK BEING WELL TO OUR NORTH AND WEST...BUT THEY DIFFER
ON HOW MUCH WARM AIR IS DRAWN UP AHEAD OF THE SYSTEM. ONE THING IS
FOR SURE...THE COLD AIR WHICH WILL BE IN PLACE THIS UPCOMING
WEEKEND WILL BE RETREATING OUT TO SEA BUT MANY QUESTIONS REMAIN ON
HOW MUCH OF IT REMAINS BEHIND. WITH NO CLEAR-CUT SOLUTION
CONTINUED TO PLAY IT A RAIN/SNOW MIX TUESDAY WITH A TRANSITION TO
SNOW TUESDAY NIGHT INTO WEDNESDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
RAIN AND LIGHT FOG WILL PERSIST OVERNIGHT AND INTO THURSDAY
AFTERNOON, KEEPING THE TERMINALS IN MVFR TERRITORY. CEILINGS WILL
RANGE FROM 1500 TO 2500 FEET, WITH VISIBILITIES FLUCTUATING
BETWEEN 3SM AND P6SM AS RAIN BANDS MOVE IN AND OUT.
AT THE HIGHER ELEVATION BGM TERMINAL, BORDERLINE IFR CONDITIONS
WILL HOLD THROUGH AT LEAST LATE MORNING. CEILINGS WILL BE BETWEEN
500 AND 1000 FEET WITH VISIBILITIES BETWEEN 2SM AND 6SM.
WINDS WILL BE GUSTY THROUGH 9Z, WITH OCCASIONAL EAST-SOUTHEAST
GUSTS OF 15 TO 20 KNOTS. WINDS WILL DIE DOWN A BIT TOWARD SUNRISE
AS THE PRESSURE GRADIENT SLACKENS.
RAIN SHOWERS WILL CHANGE TO SNOW SHOWERS LATE THURSDAY NIGHT OR
EARLY FRIDAY MORNING, WITH TEMPO MVFR TO BORDERLINE IFR CONDITIONS
POSSIBLE.
.OUTLOOK...
FRI...GUSTY WINDS AND PSBL RESTRICTIONS IN SHSN...ESPECIALLY
KRME/KSYR.
FRI NGT/SAT...MVFR/IFR IN LAKE-EFFECT SHSN KSYR/KRME...WITH
RESTRICTIONS ALSO PSBL AT KBGM/KITH/KELM.
SUN/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
PAZ040-048-072.
NY...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ036-045-062.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ009-037-
046-057.
&&
$$
SYNOPSIS...MDP
NEAR TERM...HEDEN/MDP
SHORT TERM...MLJ
LONG TERM...HEDEN
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1255 PM EST THU JAN 12 2012
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL CAUSE BREEZY
WESTERLY WINDS ACROSS THE CAROLINAS AND SOUTHERN VIRGINIA TODAY. A
POLAR COLD FRONT WILL CROSS THE REGION TONIGHT. MUCH COOLER AIR WILL
SETTLE OVER THE AREA FRIDAY AND LINGER INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM THURSDAY...
DEEP BUT TEMPORARY WEST-SOUTHWESTERLY FLOW OBSERVED OVER CENTRAL NC
THIS MORNING AS ONE LOW PRESSURE SYSTEM IS LIFTING TOWARD NEW
ENGLAND AND A SECOND CLIPPER LOW IS DIVING THROUGH THE MIDWEST
STATES. THE AIRMASS AROUND THE SOUTHEAST IS FAIRLY UNIFORM...SO
HIGHS TODAY WILL MOSTLY BE DEPENDING ON MIXING AS GRADIENT WINDS
INCREASE AHEAD OF THE APPROACHING DEEP CLIPPER SYSTEM. FORECAST
SOUNDINGS SHOW MIXING TO AROUND 900MB...WHICH MAY BE SLIGHTLY
UNDERDONE GIVEN THAT WINDS ARE ALREADY INCREASING TO 12-15KT AND
WILL EVENTUALLY GUST TO NEAR 25KT THIS AFTERNOON. A RIBBON OF
STRATUS TRAPPED BELOW THE SUBSIDENCE INVERSION OVER THE FOOTHILLS
AND WESTERN PIEDMONT HAS RESISTED MIXING SO FAR...AND ALSO A LARGE
AREA IF STRATUS IS ADVANCING THROUGH UPSTATE SC AND MAY BLEED INTO
AREAS NEAR THE YADKIN RIVER. CLOUD COVER WILL BE ADJUSTED OVER THE
WESTERN COUNTIES BASED ON SOME OF THE HRRR AVIATION GUIDANCE AND
TEMPS MAY ULTIMATELY BE HELD DOWN A COUPLE OF DEGREES IN THE WEST.
EXPECT HIGHS OF 58-65 NORTHWEST TO SOUTHEAST. -SMITH
AS THE UPPER TROUGH AND SFC COLD FRONT CROSSES THE MTNS THIS
EVENING...STRONG FRONTOGENETIC FORCING WITHIN UPPER JET EXIT REGION
WILL SUPPORT A BAND OF SHALLOW CONVECTION THAT WILL QUICKLY MOVE
EAST ACROSS CENTRAL NC BETWEEN 00 TO 06Z. MOISTURE WILL BE LIMITED
WITH EXPECTED SCATTERED SHOWERS TENDING TO DRY UP/DISSIPATE AS THEY
ADVANCE EAST OFF THE HIGHER TERRAIN AS FLOW QUICKLY BECOMES WESTERLY
WITH STRONG DRY COLD AIR ADVECTION ENSUING. ANY PRECIP WILL BE ALL
LIQUID WITH COLD AIR TRAILING THE EXITING SHALLOW MOIST LAYER. SKIES
SHOULD CLEAR OFF MIDNIGHT WITH CAA PLUNGING TEMPERATURES DOWN INTO
THE LOWER 30S NORTHWEST TO MID/UPPER 30S SOUTHEAST.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 315 AM THURSDAY...
FRIDAY AND FRIDAY NIGHT:
A TIGHT PRESSURE GRADIENT WILL CONTINUE ON FRIDAY BETWEEN THE
DEEPENING LOW PRESSURE OVER NEW ENGLAND AND SURFACE HIGH PRESSURE
OVER THE GULF COAST STATES. INVERSELY TO TODAY...THESE WINDS WILL
EXACERBATE THE BUILDING ARCTIC AIRMASS AS LOW-LEVEL THICKNESSES 12Z
FRIDAY MORNING ARE FORECAST TO START OUT 30 METERS BELOW
NORMAL...SUPPORTING HIGHS IN THE LOWER 40S NW TO UPPER 40S
SOUTHEAST...WITH BLUSTERY WESTERLY WINDS PRODUCING WIND CHILLS
OF 35 TO 40. PRESSURE GRADIENT RELAXES FRIDAY EVENING/NIGHT AS LOW
OVER NEW ENGLAND CONTINUES TO MOVE AWAY. COLD OVERNIGHT LOWS IN THE
IN THE LOWER TO MID 20S.
SATURDAY...L/W TROUGH OVER THE EASTERN HALF OF THE U.S WILL MAINTAIN
COOLER THAN NORMAL CONDITIONS ACROSS OUR REGION. 850MB THERMAL
TROUGH LIES ACROSS THE REGION SATURDAY WITH 850MB TEMPS MINUS
6-MINUS 8 DEGREES C. THICKNESSES 30-35M BELOW NORMAL WHICH WOULD
YIELD MAX TEMPS NO HIGHER THAN THE UPPER 30S TO NEAR 40 IN THE
PIEDMONT. ADJUSTING FOR POTENTIAL AIR MASS MODIFICATION...EXPECT MAX
TEMPS IN THE LOW-MID 40S OVER THE PIEDMONT AND NORTHERN COASTAL
PLAIN..AND UPPER 40S ACROSS THE FAR SOUTH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 315 AM THURSDAY...
SATURDAY NIGHT...MODEL GUIDANCE HAS TRENDED FARTHER SOUTH WITH A
VORT MAX IN THE NW FLOW TRAVERSING SEWD ON THE BACK SIDE OF THE
TROUGH. DUE TO THE MORE SOUTHWARD PATH OF THE VORT MAX INTO THE BASE
OF THE UPPER TROUGH OVER OUR REGION...WE HAVE A BETTER CHANCE OF
SEEING MORE CLOUDS AND POSSIBLY SOME LIGHT PRECIP. 00Z GFS
RH/TEMP/LIFT CROSS SECTION FOR 06Z SUNDAY DOES DEPICT ADEQUATE
MOISTURE AND LIFT IN THE FAVORED ICE NUCLEATION REGION TO GENERATE
SNOWFLAKES ALOFT. HOWEVER THE LIFT DOES NOT EXTEND DOWN INTO THE
LOWEST 8K FT OF THE ATMOSPHERE PLUS THE SUBCLOUD LAYER IS QUITE DRY
SUGGESTING A HIGH PROBABILITY OF EVAPORATION. PARTIAL THICKNESSES
SUGGEST THAT ANY PRECIP THAT DOES REACH THE SURFACE WOULD BE LIGHT
SNOW. SINCE THIS IS THE FIRST ITERATION OF THIS POSSIBLE SCENARIO BY
THE MODELS...AND THE NEAR SURFACE CONDITIONS NOT IDEAL FOR
PRECIP...WILL REFRAIN FROM MENTIONING PRECIP IN THE FORECAST AT THIS
TIME. IF PRECIP WERE TO OCCUR...WOULD EXPECT NOTHING MORE THAN A FEW
SNOW FLURRIES...MAINLY LATE SATURDAY EVENING INTO THE OVERNIGHT
HOURS. DUE TO THE INCREASE IN CLOUD COVERAGE...EXPECT MIN
TEMPS TO BE A COUPLE OF DEGREES WARMER THAN FRIDAY NIGHT. MOST
PLACES SHOULD BE IN THE UPPER 20S.
SUNDAY INTO MONDAY...STRONG SUBSIDENCE IN THE WAKE OF THE EXITING
VORT MAX SUNDAY MORNING WILL LEAD TO CLEARING SKIES WITH SUNNY SKIES
EXPECTED AREAWIDE BY EARLY AFTERNOON. NW FLOW AT 850MB IN THE WAKE
OF THE SYSTEM SUNDAY DEPICT NEUTRAL ADVECTION AT THIS TIME.
LINGERING EFFECTS OF 850MB THERMAL TROUGH OVER THE REGION SHOULD
YIELD MAX TEMPS SLIGHTLY BELOW NORMAL. AFTERNOON TEMPS IN THE
MID-UPPERS 40S PROJECTED.
SURFACE RIDGE OVER THE REGION SUNDAY NIGHT SHOULD CREATE IDEAL
CONDITIONS FOR RADIATIONAL COOLING. MIN TEMPS MID 20S WITH LOWER
20S POSSIBLE IN THE NORMALLY COLDER LOCALES.
MODEST RECOVERY BEGINS MONDAY AS SURFACE RIDGE SHIFTS EAST AND
RETURN FLOW COMMENCES LATE IN THE DAY. AIR MASS MODIFICATION SHOULD
RESULT IN MAX TEMPS CLOSE TO NORMAL FOR MID JANUARY...UPPER 40S TO
THE LOWER 50S.
MONDAY NIGHT INTO TUESDAY...MODELS HAVE TRENDED WETTER WITH THIS
PARTICULAR MODEL RUN. BOTH THE 00Z GFS AND 00Z ECMWF PAINT LIGHT
PRECIP OVER CENTRAL NC MONDAY NIGHT IN THE LOW LEVEL WAA REGIME.
ISENTROPIC UPGLIDE APPEARS TO BE BEST IN THE 285-290K LAYER. WHILE
CANNOT RULE SPOTTY PRECIP...LOW LEVEL AIR MASS WILL BE QUITE DRY
MONDAY WITH DEWPOINTS IN THE TEENS. THUS THE PRECIP GENERATED BY THE
MODELS MAY ACTUALLY GO INTO MOISTENING THE SUB CLOUD LAYER TO
SATURATION. WILL KEEP POPS BELOW 20 PERCENT BUT DID RAISE MIN TEMPS
A COUPLE OF DEGREES DUE TO THICKENING CLOUDS.
NEXT MID-UPPER LEVEL S/W IN THE BROAD TROUGH OVER THE EASTERN U.S.
PROJECTED TO ADVANCE EAST FROM THE MID MS VALLEY INTO THE OH VALLEY
TUESDAY. THIS FEATURE WILL INDUCE WSW FLOW ALOFT. MEANWHILE N-S
ORIENTATION OF THE SURFACE RIDGE OFF THE EASTERN SEABOARD YIELDS A
LOW LEVEL S-SW FLOW OVER THE CAROLINAS ORIGINATING FROM THE CENTRAL
GULF. THIS SUGGEST A SHOT OF LOW LEVEL MOISTURE TRANSPORT INTO OUR
REGION AHEAD OF THE S/W AND ATTENDANT SURFACE FRONT. SINCE WE ARE
TALKING ABOUT DAY6/7...WILL ADJUST POP ONLY A TAD TO ABOUT 30
PERCENT IN THE WEST AND MAINTAIN A SLIGHT CHANCE IN THE EAST. MODEL
TIMING SUGGEST HIGHEST THREAT FOR PRECIP TUESDAY AFTERNOON-EARLY
TUESDAY NIGHT. SYSTEM EXITS REGION WEDNESDAY LEADING TO CLEARING
SKIES. TEMPS BEHIND FRONT WILL BE SLIGHTLY COOLER BUT NOT
OUTRAGEOUSLY COLD SINCE HIGH APPEARS TO BE OF PACIFIC ORIGIN WITH
SOME MODIFIED CP INFLUENCE.
&&
.AVIATION /18Z THURSDAY THROUGH MONDAY/...
AS OF 1255 PM THURSDAY...
STRATUS OVER THE WESTERN PIEDMONT THIS MORNING HAS BEEN SLOW TO LIFT
AND SCATTER...SO SOME LOW STRATUS/STRATOCU ARE AFFECTING AREAS IN
AROUND THE KINT/KGSO TERMINALS. FURTHER SOUTH...STRATUS OVER SC HAS
MOVED RATHER QUICKLY TO THE NORTH-NORTHEAST...AND SOME MVFR CEILINGS
OF 2-3KT ARE BEING REPORTED OVER THE SOUTHERN PIEDMONT AND
SANDHILLS. DUE TO THIS... THE CURRENT TAF PACKAGE WILL MAINTAIN
MVFR CEILINGS AT KGSO/KINT/KFAY INTO THE EVENING HOURS AS INCREASING
MOISTURE AND POSSIBLY A FEW SHOWERS ASSOCIATED WITH AN UPPER
DISTURBANCE APPROACHING FROM THE NORTHWEST SHOULD KEEP CEILINGS
PREDOMINATELY BELOW 3K FT. ANY SHOWERS AND MVFR CEILINGS WILL
EVENTUALLY REACH KRDU AND KRWI LATE THIS EVENING...BUT SKIES ARE
EXPECTED TO CLEAR FROM WEST TO EAST AFTER MIDNIGHT AS THE
AFOREMENTIONED DISTURBANCE SWINGS ACROSS THE AREA. BRISK
WEST-SOUTHWESTERLY WINDS OF 12-15KT AND GUSTS INTO THE LOW TO MID
20KT RANGE WILL LIKELY CONTINUE INTO THE OVERNIGHT HOURS...SWITCHING
TO MORE WESTERLY ON FRIDAY BUT REMAINING GUSTY.
OUTLOOK...
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD...OUTSIDE OF A BRIEF
PERIOD MVFR CEILINGS SATURDAY NIGHT AS ANOTHER CLIPPER SYSTEM SWINGS
THROUGH THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...CBL/SMITH
SHORT TERM...CBL/WSS
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EST THU JAN 12 2012
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL CAUSE BREEZY
WESTERLY WINDS ACROSS THE CAROLINAS AND SOUTHERN VIRGINIA TODAY. A
POLAR COLD FRONT WILL CROSS THE REGION TONIGHT. MUCH COOLER AIR WILL
SETTLE OVER THE AREA FRIDAY AND LINGER INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM THURSDAY...
DEEP BUT TEMPORARY WEST-SOUTHWESTERLY FLOW OBSERVED OVER CENTRAL NC
THIS MORNING AS ONE LOW PRESSURE SYSTEM IS LIFTING TOWARD NEW
ENGLAND AND A SECOND CLIPPER LOW IS DIVING THROUGH THE MIDWEST
STATES. THE AIRMASS AROUND THE SOUTHEAST IS FAIRLY UNIFORM...SO
HIGHS TODAY WILL MOSTLY BE DEPENDING ON MIXING AS GRADIENT WINDS
INCREASE AHEAD OF THE APPROACHING DEEP CLIPPER SYSTEM. FORECAST
SOUNDINGS SHOW MIXING TO AROUND 900MB...WHICH MAY BE SLIGHTLY
UNDERDONE GIVEN THAT WINDS ARE ALREADY INCREASING TO 12-15KT AND
WILL EVENTUALLY GUST TO NEAR 25KT THIS AFTERNOON. A RIBBON OF
STRATUS TRAPPED BELOW THE SUBSIDENCE INVERSION OVER THE FOOTHILLS
AND WESTERN PIEDMONT HAS RESISTED MIXING SO FAR...AND ALSO A LARGE
AREA IF STRATUS IS ADVANCING THROUGH UPSTATE SC AND MAY BLEED INTO
AREAS NEAR THE YADKIN RIVER. CLOUD COVER WILL BE ADJUSTED OVER THE
WESTERN COUNTIES BASED ON SOME OF THE HRRR AVIATION GUIDANCE AND
TEMPS MAY ULTIMATELY BE HELD DOWN A COUPLE OF DEGREES IN THE WEST.
EXPECT HIGHS OF 58-65 NORTHWEST TO SOUTHEAST. -SMITH
AS THE UPPER TROUGH AND SFC COLD FRONT CROSSES THE MTNS THIS
EVENING...STRONG FRONTOGENETIC FORCING WITHIN UPPER JET EXIT REGION
WILL SUPPORT A BAND OF SHALLOW CONVECTION THAT WILL QUICKLY MOVE
EAST ACROSS CENTRAL NC BETWEEN 00 TO 06Z. MOISTURE WILL BE LIMITED
WITH EXPECTED SCATTERED SHOWERS TENDING TO DRY UP/DISSIPATE AS THEY
ADVANCE EAST OFF THE HIGHER TERRAIN AS FLOW QUICKLY BECOMES WESTERLY
WITH STRONG DRY COLD AIR ADVECTION ENSUING. ANY PRECIP WILL BE ALL
LIQUID WITH COLD AIR TRAILING THE EXITING SHALLOW MOIST LAYER. SKIES
SHOULD CLEAR OFF MIDNIGHT WITH CAA PLUNGING TEMPERATURES DOWN INTO
THE LOWER 30S NORTHWEST TO MID/UPPER 30S SOUTHEAST.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 315 AM THURSDAY...
FRIDAY AND FRIDAY NIGHT:
A TIGHT PRESSURE GRADIENT WILL CONTINUE ON FRIDAY BETWEEN THE
DEEPENING LOW PRESSURE OVER NEW ENGLAND AND SURFACE HIGH PRESSURE
OVER THE GULF COAST STATES. INVERSELY TO TODAY...THESE WINDS WILL
EXACERBATE THE BUILDING ARCTIC AIRMASS AS LOW-LEVEL THICKNESSES 12Z
FRIDAY MORNING ARE FORECAST TO START OUT 30 METERS BELOW
NORMAL...SUPPORTING HIGHS IN THE LOWER 40S NW TO UPPER 40S
SOUTHEAST...WITH BLUSTERY WESTERLY WINDS PRODUCING WIND CHILLS
OF 35 TO 40. PRESSURE GRADIENT RELAXES FRIDAY EVENING/NIGHT AS LOW
OVER NEW ENGLAND CONTINUES TO MOVE AWAY. COLD OVERNIGHT LOWS IN THE
IN THE LOWER TO MID 20S.
SATURDAY...L/W TROUGH OVER THE EASTERN HALF OF THE U.S WILL MAINTAIN
COOLER THAN NORMAL CONDITIONS ACROSS OUR REGION. 850MB THERMAL
TROUGH LIES ACROSS THE REGION SATURDAY WITH 850MB TEMPS MINUS
6-MINUS 8 DEGREES C. THICKNESSES 30-35M BELOW NORMAL WHICH WOULD
YIELD MAX TEMPS NO HIGHER THAN THE UPPER 30S TO NEAR 40 IN THE
PIEDMONT. ADJUSTING FOR POTENTIAL AIR MASS MODIFICATION...EXPECT MAX
TEMPS IN THE LOW-MID 40S OVER THE PIEDMONT AND NORTHERN COASTAL
PLAIN..AND UPPER 40S ACROSS THE FAR SOUTH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 315 AM THURSDAY...
SATURDAY NIGHT...MODEL GUIDANCE HAS TRENDED FARTHER SOUTH WITH A
VORT MAX IN THE NW FLOW TRAVERSING SEWD ON THE BACK SIDE OF THE
TROUGH. DUE TO THE MORE SOUTHWARD PATH OF THE VORT MAX INTO THE BASE
OF THE UPPER TROUGH OVER OUR REGION...WE HAVE A BETTER CHANCE OF
SEEING MORE CLOUDS AND POSSIBLY SOME LIGHT PRECIP. 00Z GFS
RH/TEMP/LIFT CROSS SECTION FOR 06Z SUNDAY DOES DEPICT ADEQUATE
MOISTURE AND LIFT IN THE FAVORED ICE NUCLEATION REGION TO GENERATE
SNOWFLAKES ALOFT. HOWEVER THE LIFT DOES NOT EXTEND DOWN INTO THE
LOWEST 8K FT OF THE ATMOSPHERE PLUS THE SUBCLOUD LAYER IS QUITE DRY
SUGGESTING A HIGH PROBABILITY OF EVAPORATION. PARTIAL THICKNESSES
SUGGEST THAT ANY PRECIP THAT DOES REACH THE SURFACE WOULD BE LIGHT
SNOW. SINCE THIS IS THE FIRST ITERATION OF THIS POSSIBLE SCENARIO BY
THE MODELS...AND THE NEAR SURFACE CONDITIONS NOT IDEAL FOR
PRECIP...WILL REFRAIN FROM MENTIONING PRECIP IN THE FORECAST AT THIS
TIME. IF PRECIP WERE TO OCCUR...WOULD EXPECT NOTHING MORE THAN A FEW
SNOW FLURRIES...MAINLY LATE SATURDAY EVENING INTO THE OVERNIGHT
HOURS. DUE TO THE INCREASE IN CLOUD COVERAGE...EXPECT MIN
TEMPS TO BE A COUPLE OF DEGREES WARMER THAN FRIDAY NIGHT. MOST
PLACES SHOULD BE IN THE UPPER 20S.
SUNDAY INTO MONDAY...STRONG SUBSIDENCE IN THE WAKE OF THE EXITING
VORT MAX SUNDAY MORNING WILL LEAD TO CLEARING SKIES WITH SUNNY SKIES
EXPECTED AREAWIDE BY EARLY AFTERNOON. NW FLOW AT 850MB IN THE WAKE
OF THE SYSTEM SUNDAY DEPICT NEUTRAL ADVECTION AT THIS TIME.
LINGERING EFFECTS OF 850MB THERMAL TROUGH OVER THE REGION SHOULD
YIELD MAX TEMPS SLIGHTLY BELOW NORMAL. AFTERNOON TEMPS IN THE
MID-UPPERS 40S PROJECTED.
SURFACE RIDGE OVER THE REGION SUNDAY NIGHT SHOULD CREATE IDEAL
CONDITIONS FOR RADIATIONAL COOLING. MIN TEMPS MID 20S WITH LOWER
20S POSSIBLE IN THE NORMALLY COLDER LOCALES.
MODEST RECOVERY BEGINS MONDAY AS SURFACE RIDGE SHIFTS EAST AND
RETURN FLOW COMMENCES LATE IN THE DAY. AIR MASS MODIFICATION SHOULD
RESULT IN MAX TEMPS CLOSE TO NORMAL FOR MID JANUARY...UPPER 40S TO
THE LOWER 50S.
MONDAY NIGHT INTO TUESDAY...MODELS HAVE TRENDED WETTER WITH THIS
PARTICULAR MODEL RUN. BOTH THE 00Z GFS AND 00Z ECMWF PAINT LIGHT
PRECIP OVER CENTRAL NC MONDAY NIGHT IN THE LOW LEVEL WAA REGIME.
ISENTROPIC UPGLIDE APPEARS TO BE BEST IN THE 285-290K LAYER. WHILE
CANNOT RULE SPOTTY PRECIP...LOW LEVEL AIR MASS WILL BE QUITE DRY
MONDAY WITH DEWPOINTS IN THE TEENS. THUS THE PRECIP GENERATED BY THE
MODELS MAY ACTUALLY GO INTO MOISTENING THE SUB CLOUD LAYER TO
SATURATION. WILL KEEP POPS BELOW 20 PERCENT BUT DID RAISE MIN TEMPS
A COUPLE OF DEGREES DUE TO THICKENING CLOUDS.
NEXT MID-UPPER LEVEL S/W IN THE BROAD TROUGH OVER THE EASTERN U.S.
PROJECTED TO ADVANCE EAST FROM THE MID MS VALLEY INTO THE OH VALLEY
TUESDAY. THIS FEATURE WILL INDUCE WSW FLOW ALOFT. MEANWHILE N-S
ORIENTATION OF THE SURFACE RIDGE OFF THE EASTERN SEABOARD YIELDS A
LOW LEVEL S-SW FLOW OVER THE CAROLINAS ORIGINATING FROM THE CENTRAL
GULF. THIS SUGGEST A SHOT OF LOW LEVEL MOISTURE TRANSPORT INTO OUR
REGION AHEAD OF THE S/W AND ATTENDANT SURFACE FRONT. SINCE WE ARE
TALKING ABOUT DAY6/7...WILL ADJUST POP ONLY A TAD TO ABOUT 30
PERCENT IN THE WEST AND MAINTAIN A SLIGHT CHANCE IN THE EAST. MODEL
TIMING SUGGEST HIGHEST THREAT FOR PRECIP TUESDAY AFTERNOON-EARLY
TUESDAY NIGHT. SYSTEM EXITS REGION WEDNESDAY LEADING TO CLEARING
SKIES. TEMPS BEHIND FRONT WILL BE SLIGHTLY COOLER BUT NOT
OUTRAGEOUSLY COLD SINCE HIGH APPEARS TO BE OF PACIFIC ORIGIN WITH
SOME MODIFIED CP INFLUENCE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 630 AM THURSDAY...
24-HR TAF PERIOD:
LOW-LEVEL MOISTURE HAS SCATTERED OUT ACROSS CENTRAL NC AS VIGOROUS
LOW PRESSURE SYSTEM ACCELERATES NORTHEASTWARD AWAY FROM THE AREA.
DEEP CYCLONIC FLOW AHEAD OF A DEEPENING LOW PRESSURE SYSTEM MOVING
THROUGH THE OHIO AND TN VALLEYS WILL RESULT IN BREEZY SWLY WINDS
TODAY WITH SCATTERED STRATOCU CLOUD BASES BETWEEN 3 TO 4KFT.
AN ARCTIC COLD FRONT WILL MOVE ACROSS THE AREA BETWEEN 00 TO 06
FRIDAY...PRODUCING A SMALL 3-5 HOUR WINDOW OF MVFR CEILINGS WITH
WIDELY SCATTERED TO ISOLATED RAIN SHOWERS. SKIES WILL QUICKLY CLEAR
OUT BEHIND THE FRONTAL PASSAGE TONIGHT.
LOOKING AHEAD:
VFR CONDITIONS WILL PREVAIL THROUGH THE WEEKEND IN ASSOC/W A
COLD/DRY AIRMASS IN PLACE. BREEZY CONDITIONS CAN BE EXPECTED AGAIN
ON FRIDAY WITH WEST-SOUTHWESTERLY WIND GUSTS OF 25 TO 30 MPH
EXPECTED. THE ONLY POTENTIAL FOR SUB-VFR CONDITIONS WOULD BE A
SHORT PERIOD SATURDAY NIGHT/SUNDAY MORNING IN ASSOC/W A CLIPPER
SYSTEM PROGRESSING ACROSS THE AREA IN NW FLOW ALOFT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...CBL/SMITH
SHORT TERM...CBL/WSS
LONG TERM...WSS
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
944 PM CST FRI JAN 13 2012
.DISCUSSION...BAND OF SNOW IS CURRENTLY MOVING ACROSS CENTRAL
NORTH DAKOTA. PRECIPITATION HAS ENDED IN THE WEST. BAND HAS SHOW
SOME TENDENCY TO DISSIPATE AS IT TRACKS SOUTH AND EAST. THIS IS
WELL DEPICTED IN THE LATEST 00Z NAM AND RUC GUIDANCE. UPDATE
INCLUDED A TRY AT POPS IN THREE HOUR BLOCKS THROUGH THE REMAINDER
OF THE NIGHT. HIGHEST POPS FROM NOW UNTIL MIDNIGHT...THEN LESSENED
POPS AS AREA TRANSITIONS EAST AFTER MIDNIGHT. HAD A REPORT OF
AROUND AN INCH AT WILLISTON EARLIER. WOULD THINK THAT MOST AREAS
IN CENTRAL NORTH DAKOTA WOULD SEE A HALF INCH OR LESS...WITH A FEW
LOCALES FROM A HALF INCH TO AN INCH...AND LIGHTER AMOUNTS EXPECTED
OVER FAR EASTERN PORTIONS OF CENTRAL NORTH DAKOTA. SOME MINOR
ADJUSTMENTS TO TEMPERATURES AND DEW POINTS WITH TEMPERATURES
EXPECTED TO RISE YET THIS EVENING IN THE FAR EAST...BEFORE
DROPPING OFF LATE. TEMPERATURES WEST WILL DROP OFF SLOWLY AS
CLOUDS CLEAR OUT...BUT WINDS WILL KEEP TEMPERATURES FROM BOTTOMING
OUT.
&&
.AVIATION...LOW PRESSURE TROUGH ACROSS CENTRAL NORTH DAKOTA THIS
EVENING. MAINLY MVFR CEILINGS ASSOCIATED WITH AN AREA OF SNOW OVER
CENTRAL NORTH DAKOTA ALONG THE TROUGH. THIS WILL TRANSLATE EAST
THROUGH THE EVENING HOURS. WIND INCREASE FOR A FEW HOURS BEHIND
THE TROUGH. SKIES ALREADY CLEARING AT WILLISTON AND
DICKINSON...SHOULD CLEAR OVER KMOT AND KBIS FROM 04-06Z AND KJMS
AROUND 09Z. WESTERLY FLOW WILL CONTINUE INTO SATURDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TWH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
229 AM EST THU JAN 12 2012
.SYNOPSIS...
A COMPLEX FRONTAL SYSTEM WILL LIFT NORTHWARD ACROSS PENNSYLVANIA
EARLY TODAY WITH STEADY RAINS TAPERING TO SCATTERED SHOWERS BY THE
AFTERNOON. MILD SOUTHWEST WINDS WILL HELP BOOST DAYTIME TEMPERATURES
SEVERAL DEGREES ABOVE NORMAL. A VIGOROUS UPPER LEVEL CLOSED LOW
AND ASSOCIATED ARCTIC FRONTAL BOUNDARY MOVING THROUGH THE OHIO
VALLEY INTO THE NORTHEAST STATES WILL BRING ACCUMULATING SNOWS TO
MUCH OF WESTERN AND CENTRAL PENNSYLVANIA LATER TONIGHT INTO
EARLY FRIDAY. TEMPERATURES WILL DROP RAPIDLY FROM WEST TO EAST BEHIND
STRONG GUSTY WINDS IN THE WAKE OF THE ARCTIC FRONTAL PASSAGE. LAKE
EFFECT AND MOUNTAIN SNOW SHOWERS WILL FOLLOW FOR THE END OF THE
WEEK AND LAST INTO THE WEEKEND...WITH ADDITIONAL SNOW ACCUMULATION
LIKELY. THE COLD AND BRISK WEATHER WILL PERSIST THROUGH THE
WEEKEND AS AN UPPER LEVEL TROUGH GRIPS THE EASTERN UNITED STATES.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
RADAR SHOWS AREA OF MOD TO LCLY HVY RNFL PIVOTING NWD ACRS THE
CENTRAL MTNS AHEAD OF POTENT SRN STREAM S/W LIFTING THRU THE
VIRGINAS INTO SRN PA. MAIN CHANGE TO NEAR TERM FCST WAS TO ADD
MENTION OF WINTRY MIX IN THE NRN MTNS AS RUC 925-850MB WET BULBS
ARE STILL NEAR 0C. THE ENHANCED PCPN RATES SHOULD AID EVAP COOLING
WITH EITHER IP OR FZRA P TYPES GIVEN WARM LYR ALOFT AND SHALLOW
COLD AIR IN THE 0-1KM LAYER.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM FRIDAY/...
WITH WINDS SHIFTING TO THE SW ON THU...MOST OF THE DAY SHOULD BE
DRY AFTER MID MORNING.
MEAN WHILE A POTENT NRN STREAM CLOSED UPPER TROUGH WILL DIG SEWD
FM THE MID MISSOURI RVR VLY ACRS THE MIDWEST STATES. AT THE
SFC...A COMPLEX FRONTAL BOUNDARY ADJOINING DOUBLE SFC LOWS OVR OH
AND ALONG THE NRN MID-ATLC COAST WILL LIFT NWD THRU PA AND
ADJACENT STATES EARLY IN THE DAY...ALLOWING THE AREA TO BREAK INTO
THE WARM SECTOR AHEAD OF SHARP ARCTIC FRONT SWEEPING THROUGH THE
OH VLY. THE NWD MVMT OF THESE LG SCALE FEATURES SHOULD BRING AN
END TO STEADIER WAA PCPN OVRRNG THE RETREATING COLD SECTOR...WITH
PCPN BCMG MORE SHOWERY IN NATURE BY THURS AFTN. MILD SSWLY WINDS
WILL ADVECT UNSEASONABLY WARM AIR INTO THE REGION HELPING TO PUSH
TEMPS 10 TO 15 DEGREES ABOVE AVERAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A *HIGH IMPACT SUB ADVISORY* EVENT LOOKS VERY LIKELY LATE THURSDAY
NIGHT THROUGH FRIDAY MORNING...AS ARCTIC AIR ARRIVES PUNCTUATED BY
A 2-3 HOUR BURST OF MODERATE TO HEAVY SNOW IN MANY AREAS. 3HR
TEMPERATURE DROPS BEHIND THE FRONT OF -15F WILL DROP TEMPS FROM
THE MID TO UPPER 30S TO THE LOW TO MID 20S FROM WEST TO EAST...
BEGINNING WITH WESTERN SECTIONS 06Z THU AND ENDING WITH LOWER SUSQ
BY 15Z. UNTREATED ROADS COULD EXPERIENCE FLASH FREEZES UNDER THESE
CONDITIONS.
VIGOROUS CLOSED H5 LOW PIVOTS ENEWD FROM IN/KY ACRS W-CENTRAL PA
INTO NY STATE THU NIGHT AND FRIDAY. STRONG HEIGHT FALLS AND ENHANCED
UVVEL/S VIA LEFT EXIT DYNAMICS ASSOC WITH 125KT UPPER JET ROUNDING
THE BASE OF THE CLOSED H5 LOW WILL CONTRIBUTE TO A "BURST" OF PCPN
OVR THE ALLEGHENIES AND CENTRAL MTNS. RAIN SHOULD QUICKLY
TRANSITION TO SNOW UPON THE ARRIVAL OF MUCH COLDER AIR BEHIND THE
SHARP ARCTIC FRONT...PROMOTING STEEP LAPSE RATES AND RAPID COLUMN
COOLING. MDL QPFS ARE IN PRETTY GOOD AGREEMENT IN GENERATING
0.25-0.50 INCH LIQUID EQUIVALENTS WHICH WOULD TRANSLATE INTO ADVY
TYPE SNOW AMTS FOR MANY AREAS. THEREFORE LIGHT TO MODERATE SNOW
POTENTIAL CURRENTLY HIGHLIGHTED IN HWO.
AS MENTIONED ABOVE...FALLING TEMPERATURES AND STRONG GUSTY WINDS
WILL BE A MAJOR CONCERN WITH THE MODIFIED ARCTIC AIR ARRIVAL. THE
LATEST MDL DATA SUGGESTS A PERIOD OF STRONG WIND GUSTS APPROACHING
40KTS WILL BE POSSIBLE ON FRIDAY IN THE WAKE OF THE ARCTIC FROPA.
STRONG WINDS ALSO HIGHLIGHTED IN THE HWO AND WIND ADVY MAY BE
NEEDED. THE STRONG WINDS COMBINED WITH THE ARRIVAL OF SHARPLY
COLDER AIR WILL DROP WIND CHILLS INTO THE SINGLE DIGITS OVR THE
NORTHERN AND WESTERN MTNS.
FINALLY...YET ANOTHER POTENTIAL HAZARD TO CONSIDER LATER IN THE
PD WILL BE LAKE EFFECT SNOWS FRI-SUN. A FAVORABLE CROSS-LAKE FETCH
SHOULD SET-UP IN THE WAKE OF THE DEEP LOW LIFTING NEWD THRU THE ST
LAWRENCE VLY ON DAY 3...WITH SOME ADDITIONAL LIFT LKLY IN ADVANCE
OF A REINFORCING S/WV TROUGH ROTATING ACRS THE GRT LKS. THE COLD
WNWLY FLOW REGIME WILL ENCOURAGE NMRS LAKE EFFECT SNOW SHOWERS/BANDS
WITH MODERATE ACCUMS POSSIBLE DOWNWIND OF LAKE ERIE OVR THE NW
SNOWBELT AND ON THE RIDGES OF THE LAUREL HIGHLANDS.
AFTER A MILD DAY ON THURSDAY...TEMPERATURES WILL AVG BELOW NORMAL
THROUGH THE REMAINDER OF THE PD. THE LW TROUGH IS FCST TO LIFT
OUT OF THE NE STATES BY EARLY NEXT WEEK. THIS SHOULD LEAD TO A
MODERATION IN TEMPS AS S/WV RIDGE SLIDES EWD FM THE MIDWEST/GRT
LKS. MEDIUM RANGE MDL AND ENSEMBLE GUID SHOWS A N-S SFC RIDGE
MIGRATING EWD OFF THE ECOAST BY NEXT TUES. THIS FEATURE SHOULD
PROVIDE FAIR AND DRY WEATHER TO START NEXT WEEK BEFORE RETURN FLOW
AND APPROACHING FRONT BRING THE NEXT THREAT OF PCPN AROUND MID-
WEEK/JANUARY 18TH.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
WIDESPREAD IFR CIGS AND RAIN EXPECTED EARLY THIS MORNING AS LOW
PRESSURE LIFTS NORTHWARD THRU THE STATE. THE HEAVIEST RAIN AND
LLWS IS ASSOCIATED WITH A LOW LVL JET. THIS FEATURE HAS ALREADY
CLEARED THE S TIER COUNTIES AT 07Z...AND SHOULD LIFT NORTH OF THE
ENTIRE STATE BY DAWN.
CONDS WILL BEGIN TO IMPROVE BY LATE THIS MORNING AND AFTN...AS LOW
PRESSURE DEPARTS THE AREA. THE IMPROVEMENT WILL BE MOST PRONOUNCED
ACROSS THE LOWER ELEVATIONS OF SE PA...WHERE VFR CONDS APPEAR LIKELY
BY AFTN. RESIDUAL LOW LVL MOISTURE ASCENDING THE W MTNS MAY RESULT
IN PERSISTENT LOW CIGS AT BFD AND JST.
A SHARP COLD FRONT WILL SWEEP INTO THE REGION TONIGHT...BRINGING A
PERIOD OF RAIN...CHANGING TO WINDBLOWN SNOW OVR THE W MTNS.
OUTLOOK...
FRI...WINDY WITH MVFR CIGS/SNOW SHOWERS W MTNS.
SAT...MVFR CIGS/SNOW SHOWERS POSSIBLE W MTNS.
SUN-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DEVOIR/MARTIN
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1247 AM EST THU JAN 12 2012
.SYNOPSIS...
A COMPLEX FRONTAL SYSTEM WILL LIFT NORTHWARD ACROSS PENNSYLVANIA
EARLY TODAY WITH STEADY RAINS TAPERING TO SCATTERED SHOWERS BY THE
AFTERNOON. MILD SOUTHWEST WINDS WILL HELP BOOST DAYTIME TEMPERATURES
SEVERAL DEGREES ABOVE NORMAL. A VIGOROUS UPPER LEVEL CLOSED LOW
AND ASSOCIATED ARCTIC FRONTAL BOUNDARY MOVING THROUGH THE OHIO
VALLEY INTO THE NORTHEAST STATES WILL BRING ACCUMULATING SNOWS TO
MUCH OF WESTERN AND CENTRAL PENNSYLVANIA LATER TONIGHT INTO
EARLY FRIDAY. TEMPERATURES WILL DROP RAPIDLY FROM WEST TO EAST BEHIND
STRONG GUSTY WINDS IN THE WAKE OF THE ARCTIC FRONTAL PASSAGE. LAKE
EFFECT AND MOUNTAIN SNOW SHOWERS WILL FOLLOW FOR THE END OF THE
WEEK AND LAST INTO THE WEEKEND...WITH ADDITIONAL SNOW ACCUMULATION
LIKELY. THE COLD AND BRISK WEATHER WILL PERSIST THROUGH THE
WEEKEND AS AN UPPER LEVEL TROUGH GRIPS THE EASTERN UNITED STATES.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
RADAR SHOWS AREA OF MOD TO LCLY HVY RNFL PIVOTING NWD ACRS THE
CENTRAL MTNS AHEAD OF POTENT SRN STREAM S/W LIFTING THRU THE
VIRGINAS INTO SRN PA. MAIN CHANGE TO NEAR TERM FCST WAS TO ADD
MENTION OF WINTRY MIX IN THE NRN MTNS AS RUC 925-850MB WET BULBS
ARE STILL NEAR 0C. THE ENHANCED PCPN RATES SHOULD AID EVAP COOLING
WITH EITHER IP OR FZRA P TYPES GIVEN WARM LYR ALOFT AND SHALLOW
COLD AIR IN THE 0-1KM LAYER.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM FRIDAY/...
WITH WINDS SHIFTING TO THE SW ON THU...MOST OF THE DAY SHOULD BE
DRY AFTER MID MORNING.
MEAN WHILE A POTENT NRN STREAM CLOSED UPPER TROUGH WILL DIG SEWD
FM THE MID MISSOURI RVR VLY ACRS THE MIDWEST STATES. AT THE
SFC...A COMPLEX FRONTAL BOUNDARY ADJOINING DOUBLE SFC LOWS OVR OH
AND ALONG THE NRN MID-ATLC COAST WILL LIFT NWD THRU PA AND
ADJACENT STATES EARLY IN THE DAY...ALLOWING THE AREA TO BREAK INTO
THE WARM SECTOR AHEAD OF SHARP ARCTIC FRONT SWEEPING THROUGH THE
OH VLY. THE NWD MVMT OF THESE LG SCALE FEATURES SHOULD BRING AN
END TO STEADIER WAA PCPN OVRRNG THE RETREATING COLD SECTOR...WITH
PCPN BCMG MORE SHOWERY IN NATURE BY THURS AFTN. MILD SSWLY WINDS
WILL ADVECT UNSEASONABLY WARM AIR INTO THE REGION HELPING TO PUSH
TEMPS 10 TO 15 DEGREES ABOVE AVERAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A *HIGH IMPACT SUB ADVISORY* EVENT LOOKS VERY LIKELY LATE THURSDAY
NIGHT THROUGH FRIDAY MORNING...AS ARCTIC AIR ARRIVES PUNCTUATED BY
A 2-3 HOUR BURST OF MODERATE TO HEAVY SNOW IN MANY AREAS. 3HR
TEMPERATURE DROPS BEHIND THE FRONT OF -15F WILL DROP TEMPS FROM
THE MID TO UPPER 30S TO THE LOW TO MID 20S FROM WEST TO EAST...
BEGINNING WITH WESTERN SECTIONS 06Z THU AND ENDING WITH LOWER SUSQ
BY 15Z. UNTREATED ROADS COULD EXPERIENCE FLASH FREEZES UNDER THESE
CONDITIONS.
VIGOROUS CLOSED H5 LOW PIVOTS ENEWD FROM IN/KY ACRS W-CENTRAL PA
INTO NY STATE THU NIGHT AND FRIDAY. STRONG HEIGHT FALLS AND ENHANCED
UVVEL/S VIA LEFT EXIT DYNAMICS ASSOC WITH 125KT UPPER JET ROUNDING
THE BASE OF THE CLOSED H5 LOW WILL CONTRIBUTE TO A "BURST" OF PCPN
OVR THE ALLEGHENIES AND CENTRAL MTNS. RAIN SHOULD QUICKLY
TRANSITION TO SNOW UPON THE ARRIVAL OF MUCH COLDER AIR BEHIND THE
SHARP ARCTIC FRONT...PROMOTING STEEP LAPSE RATES AND RAPID COLUMN
COOLING. MDL QPFS ARE IN PRETTY GOOD AGREEMENT IN GENERATING
0.25-0.50 INCH LIQUID EQUIVALENTS WHICH WOULD TRANSLATE INTO ADVY
TYPE SNOW AMTS FOR MANY AREAS. THEREFORE LIGHT TO MODERATE SNOW
POTENTIAL CURRENTLY HIGHLIGHTED IN HWO.
AS MENTIONED ABOVE...FALLING TEMPERATURES AND STRONG GUSTY WINDS
WILL BE A MAJOR CONCERN WITH THE MODIFIED ARCTIC AIR ARRIVAL. THE
LATEST MDL DATA SUGGESTS A PERIOD OF STRONG WIND GUSTS APPROACHING
40KTS WILL BE POSSIBLE ON FRIDAY IN THE WAKE OF THE ARCTIC FROPA.
STRONG WINDS ALSO HIGHLIGHTED IN THE HWO AND WIND ADVY MAY BE
NEEDED. THE STRONG WINDS COMBINED WITH THE ARRIVAL OF SHARPLY
COLDER AIR WILL DROP WIND CHILLS INTO THE SINGLE DIGITS OVR THE
NORTHERN AND WESTERN MTNS.
FINALLY...YET ANOTHER POTENTIAL HAZARD TO CONSIDER LATER IN THE
PD WILL BE LAKE EFFECT SNOWS FRI-SUN. A FAVORABLE CROSS-LAKE FETCH
SHOULD SET-UP IN THE WAKE OF THE DEEP LOW LIFTING NEWD THRU THE ST
LAWRENCE VLY ON DAY 3...WITH SOME ADDITIONAL LIFT LKLY IN ADVANCE
OF A REINFORCING S/WV TROUGH ROTATING ACRS THE GRT LKS. THE COLD
WNWLY FLOW REGIME WILL ENCOURAGE NMRS LAKE EFFECT SNOW SHOWERS/BANDS
WITH MODERATE ACCUMS POSSIBLE DOWNWIND OF LAKE ERIE OVR THE NW
SNOWBELT AND ON THE RIDGES OF THE LAUREL HIGHLANDS.
AFTER A MILD DAY ON THURSDAY...TEMPERATURES WILL AVG BELOW NORMAL
THROUGH THE REMAINDER OF THE PD. THE LW TROUGH IS FCST TO LIFT
OUT OF THE NE STATES BY EARLY NEXT WEEK. THIS SHOULD LEAD TO A
MODERATION IN TEMPS AS S/WV RIDGE SLIDES EWD FM THE MIDWEST/GRT
LKS. MEDIUM RANGE MDL AND ENSEMBLE GUID SHOWS A N-S SFC RIDGE
MIGRATING EWD OFF THE ECOAST BY NEXT TUES. THIS FEATURE SHOULD
PROVIDE FAIR AND DRY WEATHER TO START NEXT WEEK BEFORE RETURN FLOW
AND APPROACHING FRONT BRING THE NEXT THREAT OF PCPN AROUND MID-
WEEK/JANUARY 18TH.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
WIDESPREAD MVFR/IFR EXPECTED OVERNIGHT INTO THURSDAY AS THE SFC
LOW APPROACHES AND MOVES THRU. I DID KNOCK THE SFC WINDS DOWN AS
STRONG COLD AIR DAMMING IS LEADING TO A VERY STABLE BOUNDARY LAYER
AND CAPPING WIND IN THE 10-15 MPH RANGE FOR THE MOST PART. THIS
COULD PROMOTE SOME LLWS AS A 30-50KT LOW LEVEL JET ROARS IN
OVERNIGHT.
CONDITIONS WILL BEGIN TO IMPROVE THURSDAY MORNING AND AFTERNOON
AS LOW PRESSURE DEPARTS THE AREA. GUIDANCE HINTS AT A SECOND SPOKE
OF ENERGY ROTATING AROUND THE UPPER-LOW AND PUSHING A BIT MORE
PRECIP ACROSS AREA THURS NIGHT ALONG AND IN THE WAKE OF A
RELATIVELY STRONG COLD FRONT. PERIODS OF MVFR TO IFR IN SNOW WILL
BE LIKELY...ESPECIALLY ACROSS THE NRN AND WRN MTNS OF PA.
NW FLOW WILL SET UP FRI INTO SAT BEHIND DEPARTING SYSTEM...WHICH
WILL CAUSE SOME LAKE-EFFECT/UPSLOPE SNOW SHOWERS ACROSS MAINLY
THE NORTH AND WEST.
OUTLOOK...
THU...LOW PRESSURE DEPARTS AREA. DEVELOPING UPSLOPE
FLOW MAY HOLD MVFR CONDS NORTH AND WEST.
FRI-SAT...NW FLOW WITH MVFR POSS IN SCTD -SHSN MAINLY NORTH AND
WEST.
SUN-MON...GENERALLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DEVOIR/MARTIN
LONG TERM...RXR
AVIATION...LA CORTE
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
750 PM CST FRI JAN 13 2012
.DISCUSSION.../ISSUED AT 750 PM CST/
AREA OF LIGTH SNOW IN THE JAMES VALLEY CONTINUES TO FILL IN
ASSOCIATED WITH SOME 800-900MB FRONTOGENESIS. LATEST RUC SHOWS THAT
THIS TREND SHOULD CONTINUE THROUGH 06Z...SPREADING INTO THE I-29
CORRIDOR...THEN PULLING EASTWARD INTO MN AND IA AFTER 06Z THEN EAST
OF THE FORECAST AREA BY 12Z. AMOUNTS STILL LOOK TO BE RATHER LIGHT
WITH ONE HALF INCH OR LESS EXPECTED. OTHERWISE...STEADY TO SLOWLY
RISING TEMPERATURES OVERNIGHT AS FORECAST EARLIER STILL LOOK ON
TRACK.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 300 PM CST/
LATEST WATER VAPOR LOOP SHOWING A FAIRLY STRONG WAVE DIGGING INTO
EASTERN MONTANA LATE THIS AFTERNOON WHICH WILL BRING THE SHOT OF
LIGHT SNOW TO THE AREA TONIGHT. STRONGER BAROCLINICITY CONFINED TO
THE LOWEST LEVELS OF THE ATMOSPHERE AND DO NOT EXPECT THIS TO PLAY
A BIG ROLE IN PRECIPITATION PRODUCTION. HIGHER UP...AROUND
700MB...NOT MUCH OF A THERMAL GRADIENT SO AT LEAST WITH THIS EVENT
PLANNING ON FOLLOWING THE UPPER LEVEL PV ADVECTION AS WELL AS THE
750-650MB THETA E RIDGING. THIS WILL BRING A CHANCE FOR SNOW INTO
CENTRAL SOUTH DAKOTA BETWEEN 0Z AND 3Z WITH AN INCREASING CHANCE
ACROSS CENTRAL PARTS OF THE CWA FROM ABOUT 3Z THROUGH 9Z...THEN
LIKELY PEELING INTO NORTHWEST IOWA FROM ABOUT 6Z THROUGH 12Z. NOT
PLANNING ON TOO MUCH ACCUMULATION WITH MOST LOCATIONS AN INCH OR
LESS. TEMPERATURES WILL REMAIN STEADY TO RISING THROUGH THE NIGHT AS
WELL WITH MORNING TEMPERATURES ABOUT 20 DEGREES WARMER THAN THIS
MORNING.
BY SATURDAY THE BULK OF THE ACTIVITY SHOULD BE EAST OF THE AREA WITH
A MARGINALLY BREEZY NORTHWEST DEVELOPING. HIGHS MOSTLY UNCHANGED
FROM EARLIER...RANGING FROM NEAR 30 IN THE NORTHERN CWA TO THE UPPER
30S IN THE SOUTH.
A SURFACE RIDGE SLIDES QUICKLY TO THE EAST ON SATURDAY NIGHT...WITH
A SOUTHERLY FLOW RETURNING TO THE AREA DURING THE NIGHT TIME HOURS
OUT AHEAD OF A TROUGH PUSHING OUT OF THE NORTHERN ROCKIES. WITH
THIS...TEMPERATURES WILL BE TRICKY ON SATURDAY NIGHT...INITIALLY
DROPPING PRETTY QUICKLY...THEN STEADYING OUT AND RISING IN SOME
AREAS OVERNIGHT WITH LOW LEVEL WARM AIR ADVECTION AND AN INCREASING
GRADIENT. LOWS EARLY LOOKING TO BE IN THE UPPER TEENS TO LOWER 20S.
SUNDAY WILL BE THE WARMEST DAY OF THE NEXT SEVERAL OUT AHEAD OF THE
APPROACHING SURFACE TROUGH. THOUGH WITH SOME MODEL
DIFFERENCES...MIXING LOOKS TO BE AROUND 925 MB...WHERE TEMPERATURES
WILL BE APPROXIMATELY IN THE RANGE OF 1 TO 7 DEGREES C FROM NORTH TO
SOUTH...AND HIGHS WILL BE FROM LOWER 40S NORTH OF THE INTERSTATE 90
CORRIDOR TO AROUND 50 FROM LAKE ANDES TO SIOUX CITY TO STORM LAKE.
COLD FRONT DROPS SOUTHWARD ACROSS THE REGION ON SUNDAY NIGHT
BRINGING AND END TO THE WARMTH...WITH LOWS IN THE UPPER TEENS TO MID
20S.
CONFIDENCE IN MONDAY/MONDAY NIGHT DETAILS RATHER LOW...WITH MODELS
SPLIT IN THE DETAILS REGARDING TIMING AND PLACEMENT OF MIDLEVEL
THERMAL GRADIENT AND SHORTWAVE TRACKING ACROSS THE CENTRAL PLAINS
DURING THAT TIME FRAME. DOES LOOK LIKE THERE WILL BE A PERIOD OF
LIGHT SNOW ACROSS THE AREA SOMETIME LATER ON MONDAY AND MONDAY
NIGHT...WITH MAYBE AN INCH TO INCH AND HALF OR SO OF ACCUMULATION
POSSIBLE AT THIS POINT. WILL BE SOMETHING TO WATCH HOWEVER. WITH
COLD AIR ADVECTION MONDAY WILL BE COLDER WITH HIGHS MAINLY IN THE
20S.
IN THE EXTENDED...TUESDAY THROUGH FRIDAY...APPEARS TO BE GENERALLY
COLD THROUGH THE PERIOD AS A SERIES OF REINFORCING SHORTWAVES TRACK
ACROSS THE NORTHERN PLAINS/UPPER MIDWEST IN A NORTHWESTERLY UPPER
LEVEL FLOW. CANNOT RULE OUT A COUPLE PERIODS OF LIGHT SNOW DURING
THAT TIME FRAME...THOUGH HARD TO PIN DOWN WITH USUAL MODEL
DIFFERENCES. TUESDAY AND THURSDAY LOOKING TO BE THE COLDEST
DAYS...IN THE TEENS...WARMING TO 20S TO LOWER 30S BY FRIDAY.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
VFR THROUGH MOST OF THE PERIOD...WITH OCCASIONAL MVFR CEILINGS AND
VISBILITIES THROUGH 12Z AS LIGHT SNOW MOVES SOOUTHEAST ACROSS THE
REGION. LOWER CLOUDS SHOULD DISSIPATE AFTER 12Z AND NORTHWEST WINDS
OF 15 TO 25 MPH WILL DEVELOP FOR SATURDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1111 AM CST THU JAN 12 2012
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...NORTH WINDS IN THE 15 TO 25 KNOT RANGE WITH A FEW
HIGHER GUSTS TO 30KTS WILL REMAIN POSSIBLE THROUGH THIS AFTERNOON.
HOWEVER THE GENERAL TREND WILL BE GRADUALLY DOWNWARD IN SPEED FOR THE
REST OF THE DAY. WINDS WILL STAY STEADY OUT OF THE NORTH THIS
EVENING BEFORE LARGELY DROPPING OFF BEFORE MIDNIGHT. SKIES WILL
CONTINUE TO CLEAR OUT FROM NORTHWEST TO SOUTHEAST WITH ONLY HIGH
CLOUDS REMAINING. VFR CONDITIONS EXPECTED THROUGH THE NEXT 24
HOURS. /68-JGG/
&&
.PREV DISCUSSION... /ISSUED 839 AM CST THU JAN 12 2012/
DISCUSSION...FORECAST IN GENERALLY GOOD SHAPE THIS MORNING AND
HAVE MADE LITTLE OVERALL CHANGE. LATEST OBS AND PROFILER DATA
COUPLED WITH 12Z RAOB APPEAR TO SHOW A RELATIVE MAXIMUM IN THE LOW
LEVEL PRESSURE GRADIENT FROM AROUND PORT ISABEL NORTHWARD TO NEAR
VICTORIA TEXAS. LATEST RUC SEEMS TO HANDLE THIS VERY WELL SHOWING
A PERIOD OVER THE NEXT COUPLE OF HOURS WHERE OCCASIONAL GUSTS TO
AROUND 40 MPH WILL BE POSSIBLE OVER LAND...WITH FREQUENT GALES
OVER THE COASTAL WATERS. NAM/RUC CROSS SECTIONS SHOW THE VERTICAL
PRESSURE GRADIENT AND RESULTANT DOWNWARD FORCING RELAXING AS THE
BOUNDARY LAYER EXPANDS DUE TO SURFACE HEATING THIS MORNING AND
AS A RESULT PROGS EASING WINDS AFTER ABOUT 18Z WHICH APPEARS VERY
REASONABLE. HAVE ISSUED A SHORT TERM FORECAST TO MENTION THE INCREASED
WIND POTENTIAL FOR THE NEXT COUPLE OF HOURS...BUT FALLING BELOW
ADVISORY CRITERIA FOR NOW. SEE FIRE WEATHER DISCUSSION BELOW FOR
CHANGES TO THE FIRE WEATHER FORECAST PACKAGE. /68-JGG/
FIRE WEATHER...SEEING MORE FREQUENT SUSTAINED WINDS OVER 25 MPH
BEGINNING TO COME IN THIS MORNING SLIGHTLY FURTHER WEST THAN
ORIGINALLY ANTICIPATED. WITH RH EXPECTED TO WELL EXCEED CRITICAL
THRESHOLDS...AND WINDS SHOWING SIGNS OF ALSO DOING SO HAVE
EXPANDED THE RED FLAG WARNING TO INCLUDE ALL BUT ZAPATA COUNTY IN
OUR CWA UNTIL 4PM THIS AFTERNOON. /68/
PREV DISCUSSION... /ISSUED 545 AM CST THU JAN 12 2012/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...MVFR CONDITIONS WITH BKN020 LOW CLOUDS NEAR THE COAST
WITH THE RECENT PASSAGE OF A COLD FRONT. SKC UPSTREAM AND EXPECT
SOME CLEARING THIS MORNING BEFORE THICKER LOW CLOUDS DEVELOP
TONIGHT. OTHERWISE...BREEZY AND GUSTY NORTH WINDS TODAY...
DECREASING TONIGHT.
PREV DISCUSSION... /ISSUED 306 AM CST THU JAN 12 2012/
SHORT TERM /TODAY THROUGH FRIDAY/...
A COLD FRONT WILL PRETTY MUCH HAVE ARRIVED THROUGH THE CWA AS WE
OPEN THE FORECAST TODAY. BEHIND THE FRONT...AN AIR MASS WITH
MARITIME POLAR CHARACTERISTICS WILL BE ARRIVING ALONG A LINE THAT
STRETCHED NORTHWEST INTO THE PACIFIC NORTHWEST. WE ARE LOOKING FOR
BREEZY AND GUSTY NORTH WINDS EARLY ON TODAY...ESPECIALLY IN COASTAL
AREAS...WITH BKN LOW CLOUDS ALONG THE COLD FRONT THIS MORNING GIVING
WAY TO A TEMPORARY BREAK UP OF CLOUDS THIS AFTERNOON. THEN COLDER
AIR WILL EVENTUALLY RESULT IN BKN TO OVC SKIES DEVELOPING BY FRIDAY.
NO PRECIP IS FORECAST FOR TODAY...WITH HIGH TEMPERATURES REMAINING
LIMITED TO THE 50S. HIGH PRESSURE WILL SETTLE OVERHEAD TONIGHT WITH
LIGHT WINDS...AND LOW TEMPERATURES WILL DIP WELL BELOW NORMAL FRIDAY
MORNING. MAV GUIDANCE NUMBERS ACROSS THE NORTHERN TIER ARE JUST
ABOVE FREEZING...AND WE MAY SEE A FEW SPOTS HIT THE FREEZING MARK OR
BELOW FRIDAY MORNING...BUT WITH A RECOGNIZED COLD BIAS...WILL STOP
SHORT OF A FREEZE WATCH RIGHT NOW AND JUST GO WITH AN SPS FOR THE
NORTHERN COUNTIES TONIGHT. TEMPS FRIDAY WILL RECOVER INTO THE 60S
WITH LIGHT NORTHEAST TO EAST WINDS. /54/
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE WILL FLATTEN AND BEGIN TO SHIFT EAST FRIDAY
NIGHT/SATURDAY...AS A SHORTWAVE TROUGH HEADS TOWARD THE TENNESSEE
AND OHIO RIVER VALLEYS. WINDS SHOULD BECOME INCREASINGLY EASTERLY
AS THIS OCCURS...AND COULD RESULT IN A GRADUAL INCREASE IN GULF
MOISTURE OVER THE AREA HEADING INTO THE WEEKEND.
WEATHER CONDITIONS HEADING INTO THE WEEKEND SHOULD BE RATHER QUIET
/FOR THE MOST PART/. BOUNDARY LAYER MOISTURE /ALTHOUGH INCREASING/
SHOULD REMAIN RATHER LIMITED FOR THE FIRST HALF OF THE WEEKEND...AS
A BIT OF SHORTWAVE RIDGING MOVES ACROSS THE REGION. A FEW
PERTURBATIONS ARE SHOWN BY THE MODELS IN THE UPPER ATMOSPHERE JUST
TO OUR NORTH...BUT THESE ARE LIKELY REFLECTIONS OF THE SUBTROPICAL
JET. SO DESPITE AN EXPECTED INCREASE IN CLOUD COVER FOR THE
WEEKEND...LITTLE /IF ANY/ RAINFALL IS ANTICIPATED AT LEAST THROUGH
SATURDAY.
A FLY IN THE OINTMENT REMAINS THE DEVELOPMENT OF A COASTAL
TROUGH...WHICH CONTINUES TO BE SHOWN TO VARYING DEGREES BY MOST OF
THE MEDIUM-RANGE MODELS EARLY THIS MORNING. AS WINDS BECOME
SOUTHEASTERLY ACROSS THE REGION SUNDAY MORNING...LOOK FOR LOW-LEVEL
MOISTURE TO DEEPEN AT A RATHER QUICK PACE. IN FACT...PRECIPITABLE
WATER VALUES SHOULD RISE ABOVE 1.4 TO 1.5 INCHES FOR MUCH OF
SUNDAY. AND WITH THE DEPARTURE OF THE SHORTWAVE RIDGE...SOME OF THE
PERTURBED UPPER-LEVEL ENERGY TO OUR NORTH COULD WORK ITS WAY
SOUTHWARD. PLENTY OF ISENTROPIC UPGLIDE AND LOW CONDENSATION
PRESSURE DEFICITS ON THE 305K THETA SURFACE SHOULD ALSO BE AVAILABLE.
DISPENSING WITH THE WEATHER SPEAK...ALL OF THIS WILL LIKELY LEAD TO
THE POSSIBILITY OF SOME LIGHT RAIN FOR SUNDAY. RIGHT NOW...I THINK
THE GREATEST ODDS OF SEEING RAIN WILL LIKELY OCCUR EASTWARD OF THE
MIDDLE VALLEY. AS SUCH...I WILL LIKELY INCREASE THE ODDS OF SEEING
RAIN IN THESE REGIONS FOR SUNDAY. JUST A SIDE NOTE -- PROBABILITIES
IN THE NUMERICAL GUIDANCE PROBABILITIES HAVE REMAINED IN A NEARLY
STEADY-STATE MODE OVER THE PAST 4 OR 5 MODEL CYCLES. WHILE NOT THE
ONLY JUSTIFICATION FOR INCREASING RAIN PROBABILITIES...THIS DOES
INCREASE MY CONFIDENCE THAT SOMEONE WILL SEE MEASURABLE RAINFALL
ACROSS THIS REGION.
WHAT APPEARS TO BE OUR BEST OPPORTUNITY TO SEE SOME RAIN THIS
WEEKEND WILL BE RATHER SHORT-LIVED...AS MOST OF THE SYNOPTIC SCALE
FORCING SHOULD EXIT THE AREA BY MONDAY. WE WILL THEN START WATCHING
THE PROGRESSION OF AN UPPER LOW...WHICH SHOULD MOVE ONSHORE THE
SOCAL/BAJA CALIFORNIA COAST SUNDAY NIGHT. IT NOW LOOKS LIKE THIS
FEATURE SHOULD WEAKEN TO AN OPEN WAVE AS IT HEADS ACROSS THE DESERT
SOUTHWEST...AND WILL PROBABLY DO A BIT OF PHASING WITH ANOTHER
UPPER-LEVEL SYSTEM MOVING THROUGH THE NORTHERN ROCKIES.
THE EASTWARD MOVEMENT OF THIS SYSTEM SHOULD ALLOW A COLD FRONT TO
MOVE SOUTHWARD ACROSS MID-AMERICA EARLY IN THE WEEK. IT LOOKS LIKE
THE FRONT SHOULD MOVE INTO NORTH TEXAS LATE MONDAY NIGHT/TUESDAY
MORNING...THEN ACROSS OUR CORNER OF THE WORLD SOMETIME TUESDAY
NIGHT. TIMING OF THIS SYSTEM PRESENTED BY AVAILABLE MEDIUM-RANGE
GUIDANCE IS DEBATABLE. MOST MODELS PUSH THE FRONT SOUTH OF THE RIO
GRANDE BY WEDNESDAY MORNING. MEANWHILE...GUIDANCE FROM THE
HYDROMETEOROLOGICAL PREDICTION CENTER LAGS BEHIND THE OPERATIONAL
MODELS SOME 6 TO 12 HOURS. STAY TUNED.
FOR NOW...IT DOES NOT LOOK LIKE WE WILL SEE MUCH IN THE WAY OF
PRECIPITATION WITH THIS SYSTEM. WITH LOW-LEVEL MOISTURE SOMEWHAT
LIMITED...I WILL KEEP RAIN PROBABILITIES AT OR BELOW 14 PERCENT WITH
THIS FORECAST PACKAGE.
HIGHS WILL LIKELY WARM INTO THE 70S BY THIS WEEKEND...BUT MAY FALL
INTO THE 60S BY WEDNESDAY DEPENDING ON THE TIMING OF THE FRONT.
LOWS WILL LIKELY GO ABOVE NORMAL IN MOST PLACES GIVEN THE EXPECTED
CLOUD COVER DURING MOST PERIODS THROUGH NEXT WEDNESDAY. /53/
MARINE...
TODAY THROUGH FRIDAY...A COLD FRONT AND STRONG MARITIME POLAR HIGH
PRESSURE WILL SET UP GALE FORCE GUSTS THIS MORNING THROUGH LATE THIS
AFTERNOON ON THE GULF...WHILE SMALL CRAFT ADVISORY CONDITIONS WILL
EXIST ON THE LAGUNA MADRE. WAVE HEIGHTS WILL LIKELY BUILD TO 12 FEET
OFFSHORE. SMALL CRAFT ADVISORY CONDITIONS WILL LIKELY CONTINUE ON
THE GULF TONIGHT BUT CONDITIONS WILL IMPROVE FRIDAY AS HIGH PRESSURE
SPREADS OUT AND SETTLES OVER THE AREA. /54/
FRIDAY NIGHT THROUGH MONDAY...NORTHEAST TO EAST WINDS SHOULD BECOME
SOUTHEAST ACROSS THE MARINE AREA BY SUNDAY AS SURFACE HIGH PRESSURE
SHIFTS EAST. WINDS AND SEAS SHOULD REMAIN BELOW EXERCISE CAUTION OR
ADVISORY CRITERIA THROUGH MOST OF THE WEEKEND. WIND SPEEDS IN WAKE
OF A COASTAL TROUGH MAY INCREASE A BIT FOR SUNDAY NIGHT AND
MONDAY...AND COULD RESULT IN THE POSTING OF SMALL CRAFT EXERCISE
CAUTIONS OR SMALL CRAFT ADVISORIES BY THIS TIME. /53/
FIRE WEATHER...
NORTH WINDS AT 20 FEET WILL PEAK AT AROUND NOON TODAY BETWEEN 15 AND
20 MPH WITH GUSTS TO 25 MPH FOR THE INLAND AREAS...BUT THE DRIEST
AIR WILL NOT BECOME ESTABLISHED UNTIL MID AFTERNOON...JUST WHEN 20
FOOT WINDS BEGIN DECREASING. THE RELEVANT WEATHER ELEMENTS WILL THUS
BE SLIGHTLY OUT OF PHASE. MEETING THE CRITERIA FOR A RED FLAG
WARNING WILL BE MARGINAL INLAND...BUT WILL BE JUSTIFIABLE NEAR THE
COAST WHERE STRONGER WINDS OF NEAR 25 MPH AT 20 FEET WILL PREVAIL.
AS MENTIONED EARLIER...FIRE DANGER CRITERIA WILL BE MET FOR THE REST
OF THE CWA INLAND FOR SEVERAL HOURS FROM ABOUT 9 AM TO 3 PM CST
TODAY. ZAPATA COUNTY WILL BE MOST MARGINAL FOR THE FIRE DANGER
STATEMENT...WITH FORECAST RELATIVE HUMIDITY VALUES BARELY DECREASING
TO 25 PERCENT...BUT FELT IT WAS CLOSE ENOUGH TO INCLUDE. /54/
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...RED FLAG WARNING UNTIL 4 PM CST THIS AFTERNOON FOR TXZ249>257.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 PM CST THIS EVENING FOR
GMZ130-132-135.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST FRIDAY
FOR GMZ150-155-170-175.
GALE WARNING UNTIL 3 PM CST THIS AFTERNOON FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/58
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
839 AM CST THU JAN 12 2012
.DISCUSSION...FORECAST IN GENERALLY GOOD SHAPE THIS MORNING AND
HAVE MADE LITTLE OVERALL CHANGE. LATEST OBS AND PROFILER DATA
COUPLED WITH 12Z RAOB APPEAR TO SHOW A RELATIVE MAXIMUM IN THE LOW
LEVEL PRESSURE GRADIENT FROM AROUND PORT ISABEL NORTHWARD TO NEAR
VICTORIA TEXAS. LATEST RUC SEEMS TO HANDLE THIS VERY WELL SHOWING
A PERIOD OVER THE NEXT COUPLE OF HOURS WHERE OCCASIONAL GUSTS TO
AROUND 40 MPH WILL BE POSSIBLE OVER LAND...WITH FREQUENT GALES
OVER THE COASTAL WATERS. NAM/RUC CROSS SECTIONS SHOW THE VERTICAL
PRESSURE GRADIENT AND RESULTANT DOWNWARD FORCING RELAXING AS THE
BOUNDARY LAYER EXPANDS DUE TO SURFACE HEATING THIS MORNING AND
AS A RESULT PROGS EASING WINDS AFTER ABOUT 18Z WHICH APPEARS VERY
REASONABLE. HAVE ISSUED A SHORT TERM FORECAST TO MENTION THE INCREASED
WIND POTENTIAL FOR THE NEXT COUPLE OF HOURS...BUT FALLING BELOW
ADVISORY CRITERIA FOR NOW. SEE FIRE WEATHER DISCUSSION BELOW FOR
CHANGES TO THE FIRE WEATHER FORECAST PACKAGE. /68-JGG/
&&
.FIRE WEATHER...SEEING MORE FREQUENT SUSTAINED WINDS OVER 25 MPH
BEGINNING TO COME IN THIS MORNING SLIGHTLY FURTHER WEST THAN
ORIGINALLY ANTICIPATED. WITH RH EXPECTED TO WELL EXCEED CRITICAL
THRESHOLDS...AND WINDS SHOWING SIGNS OF ALSO DOING SO HAVE
EXPANDED THE RED FLAG WARNING TO INCLUDE ALL BUT ZAPATA COUNTY IN
OUR CWA UNTIL 4PM THIS AFTERNOON. /68/
&&
.PREV DISCUSSION... /ISSUED 545 AM CST THU JAN 12 2012/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...MVFR CONDITIONS WITH BKN020 LOW CLOUDS NEAR THE COAST
WITH THE RECENT PASSAGE OF A COLD FRONT. SKC UPSTREAM AND EXPECT
SOME CLEARING THIS MORNING BEFORE THICKER LOW CLOUDS DEVELOP
TONIGHT. OTHERWISE...BREEZY AND GUSTY NORTH WINDS TODAY...
DECREASING TONIGHT.
PREV DISCUSSION... /ISSUED 306 AM CST THU JAN 12 2012/
SHORT TERM /TODAY THROUGH FRIDAY/...
A COLD FRONT WILL PRETTY MUCH HAVE ARRIVED THROUGH THE CWA AS WE
OPEN THE FORECAST TODAY. BEHIND THE FRONT...AN AIR MASS WITH
MARITIME POLAR CHARACTERISTICS WILL BE ARRIVING ALONG A LINE THAT
STRETCHED NORTHWEST INTO THE PACIFIC NORTHWEST. WE ARE LOOKING FOR
BREEZY AND GUSTY NORTH WINDS EARLY ON TODAY...ESPECIALLY IN COASTAL
AREAS...WITH BKN LOW CLOUDS ALONG THE COLD FRONT THIS MORNING GIVING
WAY TO A TEMPORARY BREAK UP OF CLOUDS THIS AFTERNOON. THEN COLDER
AIR WILL EVENTUALLY RESULT IN BKN TO OVC SKIES DEVELOPING BY FRIDAY.
NO PRECIP IS FORECAST FOR TODAY...WITH HIGH TEMPERATURES REMAINING
LIMITED TO THE 50S. HIGH PRESSURE WILL SETTLE OVERHEAD TONIGHT WITH
LIGHT WINDS...AND LOW TEMPERATURES WILL DIP WELL BELOW NORMAL FRIDAY
MORNING. MAV GUIDANCE NUMBERS ACROSS THE NORTHERN TIER ARE JUST
ABOVE FREEZING...AND WE MAY SEE A FEW SPOTS HIT THE FREEZING MARK OR
BELOW FRIDAY MORNING...BUT WITH A RECOGNIZED COLD BIAS...WILL STOP
SHORT OF A FREEZE WATCH RIGHT NOW AND JUST GO WITH AN SPS FOR THE
NORTHERN COUNTIES TONIGHT. TEMPS FRIDAY WILL RECOVER INTO THE 60S
WITH LIGHT NORTHEAST TO EAST WINDS. /54/
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE WILL FLATTEN AND BEGIN TO SHIFT EAST FRIDAY
NIGHT/SATURDAY...AS A SHORTWAVE TROUGH HEADS TOWARD THE TENNESSEE
AND OHIO RIVER VALLEYS. WINDS SHOULD BECOME INCREASINGLY EASTERLY
AS THIS OCCURS...AND COULD RESULT IN A GRADUAL INCREASE IN GULF
MOISTURE OVER THE AREA HEADING INTO THE WEEKEND.
WEATHER CONDITIONS HEADING INTO THE WEEKEND SHOULD BE RATHER QUIET
/FOR THE MOST PART/. BOUNDARY LAYER MOISTURE /ALTHOUGH INCREASING/
SHOULD REMAIN RATHER LIMITED FOR THE FIRST HALF OF THE WEEKEND...AS
A BIT OF SHORTWAVE RIDGING MOVES ACROSS THE REGION. A FEW
PERTURBATIONS ARE SHOWN BY THE MODELS IN THE UPPER ATMOSPHERE JUST
TO OUR NORTH...BUT THESE ARE LIKELY REFLECTIONS OF THE SUBTROPICAL
JET. SO DESPITE AN EXPECTED INCREASE IN CLOUD COVER FOR THE
WEEKEND...LITTLE /IF ANY/ RAINFALL IS ANTICIPATED AT LEAST THROUGH
SATURDAY.
A FLY IN THE OINTMENT REMAINS THE DEVELOPMENT OF A COASTAL
TROUGH...WHICH CONTINUES TO BE SHOWN TO VARYING DEGREES BY MOST OF
THE MEDIUM-RANGE MODELS EARLY THIS MORNING. AS WINDS BECOME
SOUTHEASTERLY ACROSS THE REGION SUNDAY MORNING...LOOK FOR LOW-LEVEL
MOISTURE TO DEEPEN AT A RATHER QUICK PACE. IN FACT...PRECIPITABLE
WATER VALUES SHOULD RISE ABOVE 1.4 TO 1.5 INCHES FOR MUCH OF
SUNDAY. AND WITH THE DEPARTURE OF THE SHORTWAVE RIDGE...SOME OF THE
PERTURBED UPPER-LEVEL ENERGY TO OUR NORTH COULD WORK ITS WAY
SOUTHWARD. PLENTY OF ISENTROPIC UPGLIDE AND LOW CONDENSATION
PRESSURE DEFICITS ON THE 305K THETA SURFACE SHOULD ALSO BE AVAILABLE.
DISPENSING WITH THE WEATHER SPEAK...ALL OF THIS WILL LIKELY LEAD TO
THE POSSIBILITY OF SOME LIGHT RAIN FOR SUNDAY. RIGHT NOW...I THINK
THE GREATEST ODDS OF SEEING RAIN WILL LIKELY OCCUR EASTWARD OF THE
MIDDLE VALLEY. AS SUCH...I WILL LIKELY INCREASE THE ODDS OF SEEING
RAIN IN THESE REGIONS FOR SUNDAY. JUST A SIDE NOTE -- PROBABILITIES
IN THE NUMERICAL GUIDANCE PROBABILITIES HAVE REMAINED IN A NEARLY
STEADY-STATE MODE OVER THE PAST 4 OR 5 MODEL CYCLES. WHILE NOT THE
ONLY JUSTIFICATION FOR INCREASING RAIN PROBABILITIES...THIS DOES
INCREASE MY CONFIDENCE THAT SOMEONE WILL SEE MEASURABLE RAINFALL
ACROSS THIS REGION.
WHAT APPEARS TO BE OUR BEST OPPORTUNITY TO SEE SOME RAIN THIS
WEEKEND WILL BE RATHER SHORT-LIVED...AS MOST OF THE SYNOPTIC SCALE
FORCING SHOULD EXIT THE AREA BY MONDAY. WE WILL THEN START WATCHING
THE PROGRESSION OF AN UPPER LOW...WHICH SHOULD MOVE ONSHORE THE
SOCAL/BAJA CALIFORNIA COAST SUNDAY NIGHT. IT NOW LOOKS LIKE THIS
FEATURE SHOULD WEAKEN TO AN OPEN WAVE AS IT HEADS ACROSS THE DESERT
SOUTHWEST...AND WILL PROBABLY DO A BIT OF PHASING WITH ANOTHER
UPPER-LEVEL SYSTEM MOVING THROUGH THE NORTHERN ROCKIES.
THE EASTWARD MOVEMENT OF THIS SYSTEM SHOULD ALLOW A COLD FRONT TO
MOVE SOUTHWARD ACROSS MID-AMERICA EARLY IN THE WEEK. IT LOOKS LIKE
THE FRONT SHOULD MOVE INTO NORTH TEXAS LATE MONDAY NIGHT/TUESDAY
MORNING...THEN ACROSS OUR CORNER OF THE WORLD SOMETIME TUESDAY
NIGHT. TIMING OF THIS SYSTEM PRESENTED BY AVAILABLE MEDIUM-RANGE
GUIDANCE IS DEBATABLE. MOST MODELS PUSH THE FRONT SOUTH OF THE RIO
GRANDE BY WEDNESDAY MORNING. MEANWHILE...GUIDANCE FROM THE
HYDROMETEOROLOGICAL PREDICTION CENTER LAGS BEHIND THE OPERATIONAL
MODELS SOME 6 TO 12 HOURS. STAY TUNED.
FOR NOW...IT DOES NOT LOOK LIKE WE WILL SEE MUCH IN THE WAY OF
PRECIPITATION WITH THIS SYSTEM. WITH LOW-LEVEL MOISTURE SOMEWHAT
LIMITED...I WILL KEEP RAIN PROBABILITIES AT OR BELOW 14 PERCENT WITH
THIS FORECAST PACKAGE.
HIGHS WILL LIKELY WARM INTO THE 70S BY THIS WEEKEND...BUT MAY FALL
INTO THE 60S BY WEDNESDAY DEPENDING ON THE TIMING OF THE FRONT.
LOWS WILL LIKELY GO ABOVE NORMAL IN MOST PLACES GIVEN THE EXPECTED
CLOUD COVER DURING MOST PERIODS THROUGH NEXT WEDNESDAY. /53/
MARINE...
TODAY THROUGH FRIDAY...A COLD FRONT AND STRONG MARITIME POLAR HIGH
PRESSURE WILL SET UP GALE FORCE GUSTS THIS MORNING THROUGH LATE THIS
AFTERNOON ON THE GULF...WHILE SMALL CRAFT ADVISORY CONDITIONS WILL
EXIST ON THE LAGUNA MADRE. WAVE HEIGHTS WILL LIKELY BUILD TO 12 FEET
OFFSHORE. SMALL CRAFT ADVISORY CONDITIONS WILL LIKELY CONTINUE ON
THE GULF TONIGHT BUT CONDITIONS WILL IMPROVE FRIDAY AS HIGH PRESSURE
SPREADS OUT AND SETTLES OVER THE AREA. /54/
FRIDAY NIGHT THROUGH MONDAY...NORTHEAST TO EAST WINDS SHOULD BECOME
SOUTHEAST ACROSS THE MARINE AREA BY SUNDAY AS SURFACE HIGH PRESSURE
SHIFTS EAST. WINDS AND SEAS SHOULD REMAIN BELOW EXERCISE CAUTION OR
ADVISORY CRITERIA THROUGH MOST OF THE WEEKEND. WIND SPEEDS IN WAKE
OF A COASTAL TROUGH MAY INCREASE A BIT FOR SUNDAY NIGHT AND
MONDAY...AND COULD RESULT IN THE POSTING OF SMALL CRAFT EXERCISE
CAUTIONS OR SMALL CRAFT ADVISORIES BY THIS TIME. /53/
FIRE WEATHER...
NORTH WINDS AT 20 FEET WILL PEAK AT AROUND NOON TODAY BETWEEN 15 AND
20 MPH WITH GUSTS TO 25 MPH FOR THE INLAND AREAS...BUT THE DRIEST
AIR WILL NOT BECOME ESTABLISHED UNTIL MID AFTERNOON...JUST WHEN 20
FOOT WINDS BEGIN DECREASING. THE RELEVANT WEATHER ELEMENTS WILL THUS
BE SLIGHTLY OUT OF PHASE. MEETING THE CRITERIA FOR A RED FLAG
WARNING WILL BE MARGINAL INLAND...BUT WILL BE JUSTIFIABLE NEAR THE
COAST WHERE STRONGER WINDS OF NEAR 25 MPH AT 20 FEET WILL PREVAIL.
AS MENTIONED EARLIER...FIRE DANGER CRITERIA WILL BE MET FOR THE REST
OF THE CWA INLAND FOR SEVERAL HOURS FROM ABOUT 9 AM TO 3 PM CST
TODAY. ZAPATA COUNTY WILL BE MOST MARGINAL FOR THE FIRE DANGER
STATEMENT...WITH FORECAST RELATIVE HUMIDITY VALUES BARELY DECREASING
TO 25 PERCENT...BUT FELT IT WAS CLOSE ENOUGH TO INCLUDE. /54/
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...RED FLAG WARNING UNTIL 4 PM CST THIS AFTERNOON FOR TXZ249>257.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 PM CST THIS EVENING FOR
GMZ130-132-135.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST FRIDAY
FOR GMZ150-155-170-175.
GALE WARNING UNTIL 3 PM CST THIS AFTERNOON FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/59/58
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1134 PM CST WED JAN 11 2012
.AVIATION...
BREEZY CONDITIONS WILL PERSIST FOR MUCH OF THE OVERNIGHT AT KCDS
WITH A RETURN TO WINDY CONDITIONS DURING THE AFTERNOON. WINDS MAY
BECOME BREEZY AT KLBB DURING THE AFTERNOON BUT WILL GO LIGHT BY
EARLY IN THE EVENING.
&&
PREV DISCUSSION... /ISSUED 352 PM CST WED JAN 11 2012/
SHORT TERM...
THE SURFACE PRESSURE GRADIENT SUPPORTING TODAYS STIFF NORTHERLY
WINDS IS EXPECTED TO EASE STEADILY THIS EVENING...WITH DROP IN MOST
SURFACE WIND SPEEDS NEAR OR PRIOR TO 00Z THIS EVENING. OUR PLAN IS
TO ALLOW THE WIND ADVISORY TO RUN ITS COURSE UNTIL 00Z WITH NO
EXTENSION. WINDS PROBABLY WILL BE SLOWEST TO DROP THIS EVENING OVER
THE ROLLING PLAINS AND MAY RETAIN GREATER THAN 10 MPH WINDS UNTIL
CLOSE TO DAYBREAK ON THURSDAY. THIS SHOULD KEEP ESPECIALLY THE
SOUTHERN ROLLING PLAINS BETTER MIXED WHILE LOW TEMPERATURES
OTHERWISE TONIGHT SHOULD DROP INTO TEENS ON MOST OF THE CAPROCK AND
LOW TO MID 20S OVER ROLLING PLAINS. THE UPPER FLOW SHOULD REMAIN
SLIGHTLY ANTICYCLONICALLY CURVED IN NORTHWEST FLOW ALOFT WITH A
BRANCH OF THE POLAR JET STILL OVER THE AREA UNTIL MIDDAY THURSDAY.
THIS MAY LEAD TO AREAS OF MID CLOUDS AGAIN LATER TONIGHT AND/OR
THROUGH THURSDAY...THOUGH SOMEWHAT DIFFICULT TO ANTICIPATE. LOW
CLOUDS TONIGHT ALSO SOMEWHAT UNCERTAIN GIVEN PREDOMINANT NORTHERLY
LOW LEVEL FLOW AND VERY DRY AIR...THOUGH RUC INDICATES ABOUT 20
DEGREES MORE NORTHEAST COMPONENT AND MAINTAINS MORE H850 LAYER
MOISTURE ACROSS NORTHERN AND EASTERN ZONES. SO...APPEARS PERHAPS
BEST AREAS FOR MVFR LAYER LOW CLOUDS WOULD BE ACROSS NORTHEAST ZONES
BUT CANT RULE OUT FOR CENTRAL. EITHER WAY...A CHILLY NIGHT WILL
OCCUR WITH A FLATTER SURFACE PRESSURE GRADIENT DOMINATING THROUGH
MUCH OF THURSDAY. TRENDED HIGHS THURSDAY VERY SLIGHTLY UPWARDS ALONG
LINES OF GUIDANCE TRENDS AS WELL. RMCQUEEN
LONG TERM...
EXPECT DRY CONDITIONS AND MODERATING TEMPERATURES LATE WEEK ON
THROUGH THE WEEKEND. INITIALLY...A SHORTWAVE TROUGH EMBEDDED WITHIN
NORTHWESTERLY FLOW ALOFT WILL TRAVERSE THE AREA FRIDAY. THIS
DISTURBANCE WILL GENERATE AREAS OF MID/HIGH CLOUD BUT LITTLE ELSE.
THE NORTHWESTERLY FLOW WILL BACK WITH TIME WITH A PROGRESSIVE UPPER
RIDGE TRANSLATING OVER SATURDAY NIGHT AND SUNDAY. THIS
PATTERN...COMBINED WITH INCREASING SOUTHERLY/SOUTHWESTERLY LOW-
LEVEL FLOW...WILL PUSH HIGHS BACK ABOVE AVERAGE OVER THE WEEKEND
/LIKELY ECLIPSING THE 60 DEGREE MARK BY SUNDAY/. ONE MINOR CAVEAT
REVOLVE AROUND A CLIPPER SYSTEM DIVING INTO THE UPPER MIDWEST THAT
MAY ATTEMPT TO BACKDOOR A WEAK COLD FRONT INTO THE NORTHEAST ZONES
ON SATURDAY. EVEN IF THIS FRONT DOES MAKE IT INTO THE AREA...ONLY
MINOR IMPACTS ARE EXPECTED. THUS...HAVE TRENDED FORECAST
TEMPERATURES UP A NOTCH OVER THE WEEKEND.
ATTENTION WILL THEN TURN TO ANOTHER SHORTWAVE TROUGH /THE REMNANTS
OF THE CUTOFF LOW CURRENTLY SPINNING WELL OFF THE CALIFORNIA COAST/
THAT WILL RACE BY THE REGION IN NEAR ZONAL FLOW ALOFT ON MONDAY.
UNFORTUNATELY THE PROGRESSIVE AND OPENING/WEAKENING NATURE OF THE
SYSTEM...ALONG WITH THE DEARTH OF LOW-LEVEL MOISTURE TO WORK
WITH...WILL LIKELY KEEP THIS SYSTEM A DRY ONE LOCALLY. HOWEVER...IF
YOU LIKE WIND YOU MAY BE IN STORE FOR ANOTHER TREAT AS THE LATEST
GUIDANCE AND RAW NWP MODEL OUTPUT SUGGEST WESTERLY WINDS MAY
APPROACH OR EXCEED ADVISORY LEVELS DURING THE DAY MONDAY.
HENCE...HAVE TRENDED WINDS SPEEDS UPWARD IN THE GRIDS...THOUGH A
TOUCH BELOW ADVISORY LEVELS AT THIS POINT. THESE WINDS COULD ALSO
LOFT A BIT OF BLOWING DUST /LIKE TODAY/ AND ALSO ELEVATE THE FIRE
DANGER. HOWEVER...CURRENT PROJECTIONS DO KEEP HUMIDITIES ABOVE MORE
CRITICAL THRESHOLDS...THOUGH THIS COULD BE A BIT OPTIMISTIC AS IS
OFTEN THE CASE IN THE STRONG WESTERLY FLOW REGIME.
BEYOND MONDAY...A COLD FRONT IS PROGGED TO MOVE THROUGH EARLY
TUESDAY...DROPPING TEMPERATURES TOWARD MORE SEASONAL LEVELS. THE
LATEST ROUND OF MODEL SOLUTIONS HAVE TRENDED A LITTLE STRONGER WITH
THE FRONT...PUSHING IT THROUGH THE ENTIRE FA...AND HAVE FOLLOWED
SUITE IN THE GRIDS. THIS COOL-DOWN SHOULD BE RELATIVELY SHORT-LIVED
THOUGH AS THE SFC RIDGE IS QUICKLY SHUNTED EASTWARD UNDER MODERATE
TO STRONG MID-LEVEL ZONAL FLOW IN PLACE ACROSS MUCH OF THE CONUS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 16 41 18 47 23 / 10 0 0 0 0
TULIA 17 42 17 49 22 / 10 0 0 0 0
PLAINVIEW 18 42 19 50 23 / 10 0 0 0 0
LEVELLAND 19 43 21 51 25 / 10 0 0 0 0
LUBBOCK 19 43 21 51 23 / 10 0 0 0 0
DENVER CITY 21 42 23 49 26 / 0 0 0 0 0
BROWNFIELD 22 43 23 50 25 / 0 0 0 0 0
CHILDRESS 23 45 20 53 24 / 10 0 0 0 0
SPUR 24 46 23 53 26 / 10 0 0 0 0
ASPERMONT 25 46 25 54 25 / 10 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1114 AM CST THU JAN 12 2012
.UPDATE...
SNOW FINALLY SPREAD INTO MILWAUKEE AT 1015 THIS MORNING...BUT IT WAS
NOT FROM THE SYSTEM SNOW SPREADING EASTWARD. IT WAS FROM A SNOW BAND
SITTING OVER THE LAKE THAT PIVOTED WESTWARD INTO MILWAUKEE. IT IS
STILL NOT SNOWING IN KENOSHA. WITH THE LOW LEVELS ALREADY SATURATED
DUE TO THE COLD AIR ADVECTION...AND THE UPPER LEVELS SATURATED AS
WELL...THE MID LEVELS NEAR THE LAKE ARE VERY SLOWLY BECOMING
SATURATED. ANY DRIZZLE OR DRY WEATHER WILL BECOME SNOW AT KENOSHA
AIRPORT WITHIN THE NEXT HALF HOUR.
FRONTOGENETIC BANDS ARE EXPECTED TO DEVELOP RAPIDLY EARLY THIS
AFTERNOON ACROSS NORTHERN IL. AT THIS TIME...MODELS SHOW THIS AREA
REMAINING JUST SOUTH OF THE WI/IL BORDER...STALLING IN AN EAST-WEST
ORIENTATION. BUT THERE IS A POSSIBILITY THAT THEY COULD DRIFT INTO
SOUTHERN WI AS THE SYSTEM PIVOTS AROUND THE UPPER LOW. THE OTHER
CONCERN WILL BE WATCHING FOR LAKE EFFECT/ENHANCEMENT NEAR THE
LAKESHORE COUNTIES. THE RUC IS SHOWING A PERIOD OF NNE 1000-900MB
WINDS AND CONVERGENCE ALONG THE LAKESHORE BETWEEN 18Z TO 21Z FROM
SHEBOYGAN SOUTH THROUGH NORTHEAST IL...THOUGH THE STRONGEST
CONVERGENCE REMAINS JUST OFFSHORE. THE RUC SHOWS A FOCUSED MAX
CONVERGENCE OVER FAR SOUTHEAST WI AROUND 00Z THAT DROPS SOUTH OUT OF
THE STATE BY 03Z. THE HRRR KEEPS THE CONVERGENCE AND HIGHER PRECIP
AMOUNTS OFFSHORE WITH A MORE NNW WIND FLOW.
WILL NEED TO KEEP MONITORING THE SHORT-TERM MODELS FOR HEADLINE
CONCERNS AND KEEP STRESSING THE POOR WEATHER DURING THE AFTERNOON
COMMUTE.
&&
.AVIATION/18Z TAFS/...
EXPECT IFR/LIFR LEVELS ACROSS THE AREA THROUGH THE AFTERNOON.
CONDITIONS SHOULD BEGIN TO LIFT TO MVFR LEVELS LATER THIS EVENING
AND OVERNIGHT AS THE SNOW BEGINS TO WIND DOWN.
BY 6 PM THE KMSN AREA SHOULD HAVE AROUND 3.5 TO 4 INCHES ON THE
GROUND WITH THE PEAK OF THE SNOW OCCURRING AROUND 18-20Z. ANOTHER
INCH SHOULD OCCUR AFTER 00Z FRIDAY. AT KMKE...ABOUT 3 INCHES SHOULD
BE REALIZED BY 00Z THIS EVENING WITH ANOTHER 2 INCHES BEFORE
MIDNIGHT. THE PEAK OF THE SNOW IN MILWAUKEE WILL CLOSER TO 23-01Z.
LOOK FOR NORTHWEST WINDS OF 15 TO 25 MPH WITH A FEW GUSTS TO 30 MPH
THROUGH THE EVENT.
LAKE ENHANCED SNOW MAY CAUSE SLIGHTLY HIGHER SNOWFALL RATES AT TIMES
AT MKE AND ENW. A BAND OF SNOW EXPECTED TO LINE UP EAST TO WEST
ACROSS FAR NORTHERN IL HAS THE POSSIBILITY OF DRIFTING NORTHWARD
INTO WALWORTH AND KENOSHA COUNTIES THIS AFTERNOON AND NEEDS TO BE
MONITORED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 4 AM CST FRIDAY FOR WIZ046-047-056-
057-062-063-067>069.
WINTER WEATHER ADVISORY UNTIL 9 AM CST FRIDAY FOR WIZ051-052-
058>060-064>066-070>072.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST FRIDAY NIGHT FOR
LMZ643>646.
&&
$$
UPDATE...MRC
AREA FORECAST DISCUSSION
NWS ALBANY NY
1239 AM EST SAT JAN 14 2012
.SYNOPSIS...
LOW PRESSURE WILL DEEPEN AND INTENSIFY...AS IT MOVES
INTO THE CANADIAN MARITIMES OVERNIGHT. BLUSTERY AND COLD
CONDITIONS WILL CONTINUE OVERNIGHT WITH OCCASIONAL SNOW SHOWERS
AND FLURRIES...AS AN ARCTIC COLD FRONT MOVES THROUGH TOWARDS
DAYBREAK. ARCTIC HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN
ONTARIO LATE SATURDAY INTO SUNDAY WITH SUBSIDING WINDS...BUT
FRIGID TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1235 AM EST...SNOW SHOWERS/FLURRIES HAVE INCREASED IN AREAL
COVERAGE ONCE AGAIN FROM THE CAPITAL REGION WEST AND NORTH...WITH
A BAND OF HEAVIER SNOW SHOWERS EVIDENT ON RADAR ACROSS SOUTH
CENTRAL HERKIMER CO INTO NORTHERN SARATOGA CO. THIS BAND HAS BEEN
MOVING SLOWLY SOUTHWARD...AND AS LOW LEVEL WINDS CONTINUE
VEERING...THIS BAND SHOULD ALSO CONTINUE MOVING SOUTH...AFFECTING
THE WESTERN MOHAWK VALLEY OVER THE NEXT 1-2 HOURS...AS WELL AS
AREAS FROM THE CAPITAL REGION N AND W. WITHIN THIS BAND...LOCALLY
HEAVY BURSTS OF SNOW WILL BE POSSIBLE. EXPECT AN ADDITIONAL 1-3
INCHES ACROSS PORTIONS OF SOUTHERN HERKIMER CO...WITH GENERALLY A
DUSTING TO UNDER AN INCH ELSEWHERE. HAVE INCREASED POPS FOR THESE
AREAS ACCORDINGLY BASED ON RADAR TRENDS.
ELSEWHERE...SNOW SHOWERS ARE PERSISTING ACROSS NORTHERN
HERKIMER/HAMILTON COS. ALTHOUGH INTENSITY HAS DECREASED...STILL
CAN EXPECT UP TO AN ADDITIONAL INCH OR TWO OF ACCUM THROUGH
DAYBREAK. WILL KEEP CURRENT SUITE OF ADVISORIES FOR THIS REGION.
HAVE BOOSTED TEMPS UPWARD...AND SLOWED THE TEMP CURVE OVER THE
NEXT 3 HOURS...AS PERSISTENT CLOUDS...AND SOME LOW LEVEL WARMTH/MOISTURE
FROM THE LAKES KEEP TEMPS FROM FALLING MUCH...GENERALLY HOLDING IN
THE 25-30 RANGE. THEN...TOWARD DAYBREAK...A QUICKER DROP OFF IN
TEMPS IS EXPECTED AS THE ARCTIC COLD FRONT DRIFTS SE. ACTUAL MIN
TEMPS MAY NOT OCCUR UNTIL AROUND OR JUST AFTER DAYBREAK.
PREVIOUS DISCUSSIONS FOLLOW...
WINTER STORM WARNING AND SOME OF THE WINTER WEATHER ADVISORIES
HAVE BEEN DROPPED.
SNOW HAS DIMINISHED GREATLY ACROSS THE REGION AS THE INVERSIONS
AND MOISTURE LAYER HAVE BECOME MORE SHALLOW. LAKE EFFECT BAND
NOSING INTO HERKIMER AND HAMILTON COUNTIES RELATIVELY STABLE AND
SHOULD CONTINUE TO PRODUCE LIGHT TO MODERATE SNOW...LOCALLY HEAVY
SNOW THROUGH THE EARLY MORNING HOURS. HAVE DROPPED ALL HEADLINES
EXCEPT FOR THE WINTER WEATHER ADVISORY IN THE WESTERN MOHAWK
VALLEY AND SOUTHERN ADIRONDACKS...WHERE IT HAS BEEN EXTENDED UNTIL
6 AM. THE LAKE EFFCT BAND MAY BREAK UP BEFORE THEN BUT IT CAN BE
CANCELLED EARLY IF NECESSARY. THERE MAY BE ONLY AN INCH OR TWO
ADDITIONAL ACCUMULATION IN THOSE AREAS...WITH STORM TOTALS OF 4
TO UP TO AROUND 8 INCHES LOCALLY.
WITH THE CLOUD COVER AND THE WINDS STAYING UP...TEMPERATURES ARE
NOT FALLING MUCH...BUT UPSTREAM TEMPERATURES SHOULD ADVECT INTO
OUR REGION BY DAYBREAK. SO...LOW TEMPERATURES SEEM TO BE IN THE
BALLPARK.
PREV AFD BELOW...
WIND ADVISORY CANCELLED AS WINDS HAVE DIMINISHED.
SOME OF THE SNOW IN THE WESTERN MOHAWK VALLEY...SOUTHERN
ADIRONDACKS...SCHOHARIE VALLEY AND CATSKILLS HAS DIMINISHED. AS
THE MEAN FLOW TURNS MORE WEST AND WEST NORTHWEST...SOME LAKE
EFFECT SNOW COULD NOSE BACK INTO THE WESTERN MOHAWK VALLEY AND
SOUTHERN ADIRONDACKS. SO...WINTER WEATHER ADVISORY WILL CONTINUE
FOR THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS...BUT SNOW
CHANCES WILL BE REDUCED IN THE SCHOHARIE VALLEY AND CATSKILLS.
SNOW STILL AFFECTING THE SOUHTERN BERKSHIRES AND SOUTHERN VT SO
WINTER STORM WARNINGS WILL CONTINUE THERE. TEMPERATURES HAVE
FALLEN A BIT MORE RAPIDLY THAN WHAT WAS FORECASTED FOR THE CURRENT
TIME...BUT OVERALL LOW TEMPERATURES FOR LATER TONIGHT SHOULD BE IN
THE BALL PARK. 00Z DATA AND RADAR TRENDS WILL BE CHECKED FOR MORE
CHANGES LATER THIS EVENING.
PREV AFD BELOW...
AS OF 530 PM EST...WE ARE RECEIVING REPORTS OF 5-7 INCHES OF
SNOWFALL...AND UPSLOPE SNOWFALL IS REALLY CRANKING UP NOW ALONG
THE NRN-CNTRL TACONICS...BERKSHIRES AND SRN GREENS. WE JUST
RECEIVED A REPORT OF 5" IN DALTON...6.5" IN PITTSFIELD...7 INCHES IN SAVOY
AND LENOX...AND 6.5 INCHES IN WOODFORD VT. WE HAVE INCREASED NRN
BERKSHIRE CTY...BENNINGTON...AND WRN WINDHAM CTY VT TO WINTER
STORM WARNINGS FOR 6-12 INCHES OF HEAVY SNOW AND BLOWING SNOW. THE
UPSLOPE SNOWFALL LOOKS CLASSIC RIGHT NOW BASED ON THE KENX RADAR
RETURNS EAST OF THE I-90 CORRIDOR...AND NOW THAT THE UPPER LOW IS
OVER MAINE COUPLED WITH A SFC TROUGH MOVING OVER THE REGION. WE
INCREASED THE ADVISORY AMOUNTS FOR ERN RENSSELAER AND ERN COLUMBIA
COUNTIES TO 4-8" TOO.
PREVIOUS NEAR TERM...
AS OF 4 PM EST...THE WATER VAPOR LOOP THIS AFTERNOON HAS THE
POTENT H500 CLOSED LOW MOVING EAST OF NY INTO NEW ENGLAND. AN
IMPRESSIVE 125+KT H500 JET STREAK CONTINUES TO MOVE EAST OF NEW
ENGLAND THIS AFTERNOON. THE OCCLUDED FRONT TO THE INTENSIFYING SFC
LOW OVER SE QUEBEC BLASTED THROUGH THIS MORNING...WHICH HAS KICKED
OFF SOME SNOW SQUALLS...AND UPSLOPE SNOWFALL ALONG THE WRN SPINE
OF THE SRN GREENS MTNS...CNTRL-NRN TACONICS...AND THE BERKSHIRES.
THE LOW TO THE MID LEVEL DEFORMATION ZONE TO THE POTENT UPPER LOW
HAS CONTINUED THE SNOWFALL ALONG THE WRN DACKS...AND WRN-CNTRL MOHAWK
VALLEY.
THE UPSLOPE SNOWFALL IN ERN COLUMBIA...ERN RENSSELAER AND N-CNTRL
BERKSHIRE COUNTIES HAS BEEN IMPRESSIVE THIS AFTERNOON WITH A
REPORT OF 6 INCHES AT PERU IN THE BERKSHIRES AS OF 3 PM. SOME OF
THE KEY FEATURES FOR AN UPSLOPE SUBSYNOPTIC SNOWFALL EVENT WITH A
CLOSED LOW WERE IN PLACE WITH STRONG CYCLONIC VORTICITY
ADVECTION...COLD ADVECTION IN THE LOW LEVELS...MOIST LOW TO MID
LEVELS...AND PERSISTENT W/SW FLOW. USUALLY THIS OCCURS WHEN THE
UPPER LOW IS EAST OR NORTHEAST OF THE REGION PER THE BTV CSTAR
WORK. THIS IS A HYBRID TYPE CASE. THE LATEST FROM THE NAM12 AND
HRRR 3KM REF PRODUCT HAS THE SNOWFALL WINDING DOWN BETWEEN 00Z-
03Z. WE EXPANDED THE ADVISORY TO INCLUDE SRN BERKSHIRE CTY /JUST
NORTH THE MASS PIKE/...AS WELL AS INCLUDING THE NRN-CNTRL TACONICS.
THE SNOW REPORTS HAVE RANGED FROM 1-3 INCHES SO FAR IN
HERKIMER COUNTY AND SW HAMILTON CTY. SOME LAKE MOISTURE WILL
CONTINUE TO BE UTILIZED IN THE DEFORMATION ZONE. OROGRAPHIC
ENHANCEMENT WILL CONTINUE ALONG THE WRN DACKS. WE HAVE EXTENDED
THE WINTER WEATHER ADVISORY FOR THE SRN DACKS AND THE WRN MOHAWK
VALLEY UNTIL MIDNIGHT. BLUSTERY W/SW WINDS WILL PERSIST THIS
EVENING BLOWING THE SNOW AROUND. THE BETTER LIFT AND MOISTURE
CONVERGENCE HAS BEEN CLOSER TO THE LAKE SHORE AND OVER W-CNTRL NY
TODAY. WE PLACED THE HIGHEST SNOW TOTALS THERE OVER NRN HERKIMER
CTY WITH 4 TO 8 INCHES...AND HAVE GONE 3 TO 6 INCHES ELSEWHERE.
LOOKING AT THE BUFKIT SOUNDINGS FROM KSYR...KUCA...AND KRME...THE
INVERSION DOES LOWER TO 4-5 KFT AGL OVERNIGHT WHICH WILL DIMINISH
THE SNOW...AND THE SFC TO BOUNDARY LAYER FLOW BEGINS TO VEER MORE
TO THE NW /CLOSE TO A 300 DEGREE TRAJECTORY/ WITH THE PASSAGE OF
ANOTHER COLD FRONT /THE LEADING EDGE OF ARCTIC AIR/. THERE COULD BE
A QUICK LAKE EXTENSION DOWN THE MOHAWK VALLEY FOR SOME SCT SNOW
SHOWERS TOWARDS DAYBREAK. THE HRRR HINTS AT HIS POSSIBILITY. WE
WILL HAVE TO MONITOR IF THIS MATERIALIZES.
IN TERMS OF THE WIND ADVISORY...GUSTS HAVE GENERALLY BEEN 30-35
KTS...JUST SHORT OF WIND ADVISORY CRITERIA. HOWEVER...AS OF 4 PM
KALB JUST HAD A GUST TO 36 KTS...AND THE H925 WINDS DO INCREASE TO
35-40 KTS...AND THE H850 WINDS TO 50-60 KTS BY 00Z. WE ARE
CONCERNED A FEW GUSTS COULD REACH 40 KTS OR SO..IF WE MIX TO H925. THE
LOW LEVEL PRESSURE GRADIENT WILL BE INCREASING...AND THERE IS A SFC
TROUGH MOVING ACROSS THE REGION AT 21Z PER THE RUC. WE WILL KEEP
THE WIND ADVISORY UP UNTIL MIDNIGHT. THE WINDS WILL GRADUALLY EASE
SLIGHTLY AFTER MIDNIGHT FROM THE W AT 15-25 MPH WITH SOME GUSTS
AROUND 35 MPH.
A BATCH OF SNOW SHOWERS OR SQUALLS WILL MOVE ACROSS THE REGION
BWTN 21Z-00Z. THIS COULD PRODUCE A DUSTING TO A FEW INCHES OF
SNOWFALL IN THE NON-ADVISORY AREAS FROM THE CAPITAL REGION NORTH.
LOWS TONIGHT WILL BE CHILLY WITH 5-10F READINGS OVER THE
ADIRONDACK PARK...TEENS ELSEWHERE..EXCEPT LOWER TO MID 20S FROM
KALB SOUTH DOWN THE HUDSON RIVER VALLEY...AND EAST OF THE GREEN
MTNS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
SATURDAY...ANOTHER BOUNDARY MOVES THROUGH DURING THE MORNING...AS
THE SFC TO BOUNDARY LAYER FLOW CONTINUES TO VEER TO THE NORTHWEST.
THERE MAYBE A FEW MULTIBANDS OFF LAKE ONTARIO MAINLY IMPACTING
CNTRL NY. THE BEST CHC OF ISOLATED TO SCT SNOW SHOWERS AND
FLURRIES WILL BE WEST OF THE HUDSON RIVER VALLEY. THE STRONG
SUBSIDENCE FROM THE ARCTIC HIGH BUILDING IN WILL TEND TO SQUASH ANY
FURTHER DEVELOPMENT OF THE LAKE EFFECT SNOW GETTING INTO MOST OF
THE REGION. ANY ACCUMULATIONS FOR THE WRN MOHAWK VALLEY/ERN
CATSKILLS SHOULD BE LIGHT. OTHERWISE...COLD ADVECTION CONTINUES
OVER THE REGION WITH H850 TEMPS FALLING TO -15C TO -20C. MAX
TEMPS WILL OCCUR EARLY TOMORROW WITH HIGHS IN THE 25-30F RANGE
SOUTH AND EAST OF THE CAPITAL REGION...AND MIDS TEENS TO L20S
NORTH AND WEST...EXCEPT OVER THE SRN DACKS...WHERE SOME SINGLE
DIGITS AND LOWER TEENS WILL BE COMMON. IT WILL STILL BE BLUSTERY
WITH WINDCHILLS IN THE SINGLE DIGITS AND TEENS...AND BELOW ZERO
NORTH AND WEST OF THE CAPITAL REGION.
SATURDAY NIGHT...TRICKY FORECAST HOW FAST THE WINDS DECOUPLE WITH
THE ARCTIC HIGH BUILDING IN. WE COULD FLIRT WITH SOME ADVISORY
LEVELS WIND CHILLS OVER THE SRN DACKS...IF WE MAINTAIN WINDS IN
EXCESS OF 5 MPH. WE WILL CONTINUE THE PREVIOUS FORECASTS MENTION
IN THE HWO. OVERALL...A BITTERLY COLD NIGHT IS EXPECTED WITH LOWS
IN THE SINGLE DIGITS FROM THE CAPITAL DISTRICT SOUTH AND
EAST...AND ZERO TO 10 BELOW NORTH AND WEST...EXCEPT 10-20 BELOW IN
THE SRN DACKS.
SUNDAY-SUNDAY NIGHT...ARCTIC HIGH PRESSURE BUILDS OVER NY AND NEW
ENGLAND ON SUNDAY. MOSTLY SUNNY AND COLD CONDITIONS WILL PREVAIL
WITH HIGHS IN THE TEENS TO L20S OVER MOST OF THE REGION...EXCEPT
SOME SINGLE DIGITS OVER THE SRN DACKS...AND THE SRN GREENS. WE
START TO WARM ADVECT SUNDAY NIGHT...AS THE HIGH SLOWLY SHIFTS
DOWNSTREAM OVER NRN NEW ENGLAND. SOME CIRRUS MAY CREEP IN AHEAD OF
A WARM FRONT OVER THE GREAT LAKES REGION...AND SE ONTARIO. LOWS
WILL NOT BE AS COLD WITH MAINLY SINGLE DIGITS FROM THE MOHAWK
VALLEY...CAPITAL REGION SOUTH...AND SOME ZERO TO 10 BELOW READINGS
NORTH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A TRANQUIL WEATHER PATTERN ON MONDAY WILL TRANSITION TO A MORE
ACTIVE PATTERN TOWARD THE END OF THE WORK WEEK. A RIDGE LOOKS TO BE
IN PLACE MONDAY MORNING BUT AS THE DAY PROGRESSES...A SHORTWAVE
TROUGH IN THE MIDWEST WILL ACT TO SHIFT THE RIDGE FROM NORTHEAST
INTO THE ATLANTIC COAST. THIS SHORTWAVE WILL PROGRESS TO THE EAST
TOWARD EASTERN OHIO/W PA LATE TUESDAY INTO EARLY WEDNESDAY. THIS LOW
WILL PRODUCE WINDY CONDITIONS WITH SUSTAINED WNW WINDS AT 15-20 KTS
AND GUSTS 20-25 KTS THROUGH LATE WEDNESDAY.
THE ECMWF AND GFS BOTH SHOW THE POSITIVE TILTED TROUGH BECOMING A
NEGATIVE TROUGH OVER THE OHIO VALLEY WEDNESDAY MORNING...WITH
CYCLOGENESIS AT THE SFC OVER THE GREAT LAKES AREA AT THIS TIME. THE
MODELS AT THIS TIME SHOWS A DECENT LOW PRESSURE SYSTEM OVER THE
LAKES AND WESTERN NY MOVING NORTHEAST ALONG THE NY/CANADA BORDER. AT
THIS TIME...MODEL FORECAST SOUNDINGS SHOW THE PRECIPITATION TYPE
OVER THE FA STARTING OUT AS SNOW. BUT WITH TEMPERATURES WARMING
THROUGHOUT THE DAY...AREAS IN THE IMMEDIATE CAPITAL REGION AND SOUTH
WILL LIKELY CHANGE TO RAIN. AREAS NORTH OF ALB WILL SEE SNOW OR A
WINTRY MIX...DEPENDING ON ELEVATION.
THE GFS MODEL HAS THE SFC LOW PRESSURE SYSTEM MOVING OUT OF THE
NORTHEAST MOVING FASTER BUT ALL OF THE MODELS HAVE THE LOW PRESSURE
SYSTEMS OUT OF THE REGION BY LATE WEDNESDAY. THIS WILL BE FOLLOWED
BY ANOTHER SYSTEM...BUT MODELS LACKING CONSENSUS FOR LATE THURSDAY
INTO FRIDAY. GFS SHOWING NEGATIVELY TILTED UPPER LEVEL TROUGH WHICH
DEVELOPS A COASTAL LOW OFF OF CAPE COD. MEANWHILE THE ECMWF SHOW THE
UPPER LEVEL TROUGH HANGING BACK WEST...THEN RETREATING UP INTO
CANADA. WILL HAVE TO KEEP AN EYE AS THIS SYSTEM DEVELOPS.
NEAR NORMAL MAX TEMPS WILL WARM ON TUESDAY FROM A WARM FRONT AHEAD
OF THE APPROACHING LOW...TO 10 DEGREES ABOVE NORMAL. THIS WILL BE
FOLLOWED BY A COLD FRONT ON TUESDAY AND A STRONG NW FLOW PRODUCING
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE REST OF THE PERIOD.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
MONITORING A BAND OF LAKE EFFECT SNOW THAT CONTINUES TO MIGRATE
SOUTH ACROSS THE MOHAWK VALLEY. LATEST RUC13/HRRR DOES SUGGEST THIS
BAND WILL HAVE AN IMPACT ON KALB AND WE WILL PLACE A TEMPO GROUP FOR
MVFR CONDITIONS UP TO 09Z. OTHERWISE...HIGH END MVFR OR VFR
CONDITIONS ARE EXPECTED THIS TAF FORECAST CYCLE.
WINDS WILL REMAIN ELEVATED THANKS TO A TIGHT PRESSURE GRADIENT AND
INCREASING MIXING POTENTIAL WITH SUNRISE. WIND GUSTS COULD EXCEED
20KTS WITH A GENERAL WEST-NORTHWEST WIND DIRECTION. WINDS WILL
BECOME NORTHWEST IN THE WAKE OF THE LAST FRONTAL BOUNDARY FROM THIS
AFTERNOON INTO SATURDAY EVENING.
OUTLOOK...
SAT OVRNT-MON...VFR...NO SIG WX.
MON NT-TUE NT...MVFR...CHC IFR -SHSN/SHRA...WINTRY MIX.
WED...VFR...SLGT CHC --SHSN.
&&
.HYDROLOGY...
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE
NEXT 5 DAYS. THE ARCTIC AIR MASS WILL ALLOW ICE TO FORM AND CONTINUE TO
THICKEN ON MAIN STEM RIVERS...LAKES...AND OTHER BODIES OF WATER
THROUGH THE WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL
BY TUESDAY.
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...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ032-033-038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/NAS/WASULA
NEAR TERM...KL/NAS/WASULA
SHORT TERM...WASULA
LONG TERM...KGM/LFM
AVIATION...BGM
HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
356 AM EST SAT JAN 14 2012
.SYNOPSIS...
A COLD FRONT EXTENDED FROM NORTHERN NEW ENGLAND TO THE GREAT
LAKES EARLY THIS MORNING. THE BOUNDARY WILL PROGRESS TO THE SOUTH
AND IT SHOULD DROP INTO OUR REGION TONIGHT. COLD HIGH PRESSURE
FROM THE WEST IS EXPECTED TO INFLUENCE OUR WEATHER FOR SUNDAY AND
SUNDAY NIGHT BEFORE PASSING OUT TO SEA ON MONDAY. A WARM FRONT
FROM THE WEST AND SOUTHWEST IS ANTICIPATED TO WORK ITS WAY THROUGH
OUR REGION ON TUESDAY, FOLLOWED BY A COLD FRONT ON TUESDAY NIGHT.
AN AREA OF HIGH PRESSURE IS EXPECTED FOR WEDNESDAY AND THURSDAY. A
WEAK FRONTAL BOUNDARY FROM THE NORTHWEST MAY ARRIVE ON THURSDAY
NIGHT OR FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A 07Z SURFACE ANALYSIS PLACED A COLD FRONT FROM NEW ENGLAND TO
THE NORTHERN OHIO VALLEY. HIGH PRESSURE WAS OVER THE UPPER GREAT
LAKES WITH ANOTHER HIGH ALONG THE GULF COAST. LOW PRESSURE WAS
JUST NORTH OF THE DAKOTAS ALONG A FRONTAL BOUNDARY TO ANOTHER LOW
IN THE CENTRAL PLAINS. AN UPPER AIR ANALYSIS PLACED A DEEP TROUGH
ACROSS THE EASTERN STATES WITH SEVERAL SHORT WAVES EMBEDDED WITHIN
THE FLOW. AN AREA OF FOCUSED WAA AT 850 MB WAS ACROSS THE CENTRAL
PLAINS. A CYCLONICALLY CURVED 300 MB JET WAS FROM THE NORTHERN
ROCKIES TO THE LOWER MISSISSIPPI VALLEY THEN UP THE EAST COAST.
A STRONG SURFACE LOW WILL REMAIN IN THE CANADIAN MARITIMES TODAY.
THIS WILL RESULT IN A CONTINUED CYCLONIC FLOW OF COLD AIR ACROSS
THE ENTIRE REGION. A SECONDARY COLD FRONT WILL WRAP AROUND THIS
SURFACE LOW AND WILL BE SETTLING SOUTHWARD ACROSS OUR AREA. THE
OVERALL LOW-LEVEL MOISTURE IS LACKING WITH THIS BOUNDARY, HOWEVER
THERE IS A RIBBON OF DECENT LIFT, CONVERGENCE AND STEEPENING LOW-
LEVEL LAPSE RATES. GIVEN THE WESTERLY FLOW OF COLD AIR, SOME ADDED
MOISTURE FROM LAKE ERIE MAY COME INTO PLAY THROUGH THE DAY. SOME
OF THE HIGHER RESOLUTION MODELS LIKE THE NAM/WRF, THE SPC 4KM WRF
AND THE HRRR HINT AT A CONNECTION BETWEEN A LAKE ERIE PLUME AND
THE COLD FRONT. ALOFT, AN AREA OF CHANNELIZED VORTICITY IS
FORECAST TO PIVOT NEARLY CLOSE TO THE SURFACE FRONT. THIS MAY HELP
TO PULL THE LAKE SNOW PLUME EASTWARD IN THE FORM OF A NARROW BAND.
THE FORECAST SOUNDINGS ACROSS THE NORTHWESTERN ZONES SHOW THE
INVERSION STAYING HIGH ENOUGH TO ALLOW THE SYNOPTIC LIFT TO OCCUR
WITHIN THE FAVORABLE SNOW GROWTH REGION. IF A BAND OF SNOW DOES
DEVELOP, A QUICK BURST MAY RESULT. THE ABOVE MENTIONED MODELS, AND
TO SOME EXTENT THE GFS, BRING THIS ALL THE WAY TO THE POCONOS TO
EVEN PORTIONS OF NORTHERN NEW JERSEY. OUR CONFIDENCE IS LOW
REGARDING HOW THIS MAY PLAY OUT, BUT THERE IS THE POTENTIAL FOR A
NARROW BAND OF HEAVIER SNOW SHOWERS MOVING THROUGH PARTS OF THE
NORTHWESTERN ZONES. THIS THEN SETTLES SOUTHWARD WITH THE FRONT BUT
WEAKENS AS THE MAIN SUPPORT TRACKS FARTHER NORTH. FOR NOW, LEANED
TOWARD THE NAM/WRF FOR POPS WHICH PLACES SLIGHT CHC TO CHC RANGE
VALUES MAINLY ACROSS NORTHEASTERN PENNSYLVANIA. WE KEPT ABOUT ONE-
HALF INCH OF SNOW ACCUMULATION ACROSS THE POCONOS.
ELSEWHERE, LITTLE TO NOTHING IS EXPECTED WITH THE FRONTAL PASSAGE
OTHER THAN A BAND OF STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS.
SPEAKING OF STRATOCUMULUS, THESE WILL BE AROUND TODAY ESPECIALLY
ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY AS THE
WESTERLY FLOW MAINTAINS ENOUGH MOISTURE UNDER AN INVERSION. THE
FORECAST SOUNDINGS INDICATE WE SHOULD GET RATHER CLOSE TO THE
CONVECTIVE TEMPERATURES TODAY DESPITE THE LOWER LEVELS BEING
RATHER DRY. THIS SHOULD RESULT IN AT LEAST SOME STRATOCUMULUS
BELOW SOME HIGHER CLOUDS ACROSS THE REST OF THE CWA, WHICH MAY
RESULT IN VARYING CLOUD COVER THROUGH THE DAY.
A WESTERLY WIND WILL CONTINUE TO BE ON THE BRISK SIDE AS VERTICAL
MIXING IS MAINTAINED. THE WINDS HOWEVER ARE EXPECTED TO BE LESS
THAN WHAT WAS OBSERVED YESTERDAY, AND SETTLE DOWN LATER IN THE
AFTERNOON. AS FOR TEMPERATURES, WE MAINLY TOOK AN EVENLY WEIGHTED
BLEND OF THE MOS GUIDANCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE AFOREMENTIONED SECONDARY COLD FRONT WILL CONTINUE TO SETTLE
SOUTHWARD BEFORE POTENTIALLY DISSIPATING. THERE COULD BE SOME
LINGERING FLURRIES OR A SNOW SHOWER WITH IT ESPECIALLY IN THE
WESTERN ZONES. HOWEVER, ANYTHING WITH IT SHOULD BE WANING WITH A
SOUTHERN EXTENT AS THE OVERALL LIFT AND MOISTURE DWINDLES AS WELL
AS A GRADUAL INCREASE IN THE SUBSIDENCE AND A LESS FAVORABLE FETCH
FROM THE LAKES. THEREFORE, KEPT THE SKY COVER A BIT HIGHER FOR A
TIME WITHIN A WEST TO EAST BAND WITH THE SOUTHBOUND FRONT. THERE
MAY BE ENOUGH MID LEVEL MOISTURE AROUND TO KEEP SOME CLOUDS
AROUND, BUT OVERALL AN EVEN DRIER PUSH OF AIR FROM THE NORTH
SHOULD RESULT IN SOME SCATTERING IN THE CLOUDS ESPECIALLY SOUTH
AND EAST OF THE PHILADELPHIA METRO AREA.
AS STRENGTHENING HIGH PRESSURE BUILDS ACROSS SOUTHEASTERN CANADA
AND THE EASTERN GREAT LAKES LATE TONIGHT, THE NORTHERLY FLOW WILL
DRIVE A COLDER AIR MASS OVER OUR AREA. THE 850 MB TEMPERATURES ARE
FORECAST TO DROP TO NEAR -15C OVERNIGHT. THERE IS SOMEWHAT OF A
PRESSURE GRADIENT REMAINING DURING THE NIGHT, HOWEVER THE OVERALL
MIXING SHOULD TEND TO BECOME MUCH MORE REDUCED AS THE NIGHT WEARS
ON. THIS WILL RESULT IN A RATHER COLD NIGHT ACROSS THE ENTIRE
AREA.
AS FOR TEMPERATURES, WE GENERALLY WENT WITH A BLEND OF THE
GFS/NAM MOS WITH SOME TWEAKS MAINLY FOR THE TYPICALLY COLDER
LOCALES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MOSTLY CLEAR AND COLD WEATHER IS ANTICIPATED FOR SUNDAY AND
SUNDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS OUR REGION. MAXIMUM
TEMPERATURES SHOULD RANGE FROM THE UPPER TEENS IN THE POCONOS TO
THE MIDDLE 30S IN SOUTHERN DELAWARE. FOR SUNDAY NIGHT, READINGS
ARE FORECAST TO DROP INTO THE TEENS THROUGHOUT MOST OF OUR REGION
WITH A LIGHT WIND AND GOOD RADIATIVE CONDITIONS.
THE MID LEVEL RIDGE AXIS IS FORECAST TO PASS OVERHEAD ON MONDAY
MORNING WITH STRONG WARM ADVECTION DEVELOPING ALOFT. FROM MONDAY
INTO MONDAY EVENING WE SHOULD SEE AN INCREASE IN HIGH, THEN MID
LEVEL CLOUDS.
ON MONDAY NIGHT, A DEVELOPING JET AROUND 850 HPA WILL BE LOCATED
OVER THE OHIO RIVER VALLEY, AHEAD OF OUR NEXT WEATHER SYSTEM
APPROACHING FROM THE WEST. THE JET SHOULD DROP SLOWLY
SOUTHEASTWARD, POINTING SQUARELY AT OUR FORECAST AREA. IT WILL ACT
TO DIRECT MOISTURE INTO OUR REGION RATHER QUICKLY. MONDAY NIGHT
SHOULD START DRY. HOWEVER, PRECIPITATION IS EXPECTED TO OVERSPREAD
OUR REGION. WITH COLD DRY AIR IN PLACE AT THE LOW LEVELS, WE MAY
VERY WELL ENCOUNTER PRECIPITATION TYPE ISSUES, MAINLY IN EASTERN
PENNSYLVANIA AND NORTHERN AND CENTRAL NEW JERSEY. BASED ON THEN
EXPECTED TEMPERATURE PROFILES AND THE ANTICIPATION THAT STRONG
WARM ADVECTION ALOFT WILL CONTINUE, IT APPEARS AS THOUGH WE MAY
SEE A MIX OF MAINLY SLEET AND FREEZING RAIN IN OUR NORTHWESTERN
COUNTIES. A LITTLE SNOW IS ALSO POSSIBLE. HOWEVER, THAT WILL
DEPEND UPON A SOMEWHAT WEAKER INITIAL PUSH OF WARM AIR ALOFT THAN
MOST OF THE GUIDANCE IS CURRENTLY SUGGESTING. ON THE COASTAL
PLAIN, IT LOOKS AS THOUGH TEMPERATURES AT THE SURFACE AND ALOFT
WILL SUPPORT ALL RAIN ON MONDAY NIGHT.
AS THE WARM ADVECTION CONTINUES ON TUESDAY. THE WINTRY
PRECIPITATION SHOULD CHANGE TO ALL RAIN. THE RAIN MAY BECOME
SHOWERY DURING THE AFTERNOON. WE ARE NOT PARTICULARLY CONFIDENT IN
THE TEMPERATURE FORECAST FOR TUESDAY. THE LOW LEVEL COLD AIR MAY
BE A LITTLE MORE STUBBORN UP NORTH THAN OUR FORECAST INDICATES.
ALSO, IN OUR FAR SOUTHERN COUNTIES, SIGNIFICANT BREAKS IN THE
CLOUD COVER COULD RESULT IN TEMPERATURES HIGHER THAN THOSE WE ARE
FORECASTING.
A COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE ON TUESDAY NIGHT
WITH HIGH PRESSURE AND DRY WEATHER FOLLOWING FOR WEDNESDAY AND
THURSDAY. THE SOURCE REGION FOR THE AIR MASS WILL BE MORE FROM THE
WEST THAN THE NORTHWEST, SO TEMPERATURES WILL LIKELY BE ABOUT
NORMAL FOR THIS TIME OF THE YEAR.
A WEAK FRONTAL BOUNDARY MAY DROP INTO OUR REGION FROM THE
NORTHWEST LATE IN THE WEEK. FOR NOW, WE HAVE SIMPLY INDICATE A
SLIGHT CHANCE OF SNOW SHOWERS WITH THE FEATURE.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A STRONG LOW PRESSURE SYSTEM IN THE CANADIAN MARITIMES THROUGH
TONIGHT WILL MAINTAIN A WEST TO NORTHWEST FLOW ACROSS OUR AREA. A
SECONDARY FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA FROM LATER
THIS MORNING THROUGH THE EVENING. THERE IS NOT MUCH FORCING AND
MOISTURE WITH THIS BOUNDARY, HOWEVER THERE ARE SOME HINTS IN THE
MODEL GUIDANCE THAT MOISTURE FROM THE EASTERN GREAT LAKES GETS
PULLED EASTWARD WITH THIS FRONT. THIS MAY RESULT IN ENOUGH LOW-
LEVEL CONVERGENCE TO ALLOW FOR A NARROW BAND OF FLURRIES OR
HEAVIER SNOW SHOWERS ACROSS THE NORTHERN PORTION OF PENNSYLVANIA
INTO NORTHWESTERN NEW JERSEY. AS A RESULT, A FEW SNOW SHOWERS MAY
GET TO AT LEAST KABE. GIVEN THE LOWER CONFIDENCE WITH THE TIMING
AND EXTENT OF ANY SNOW SHOWERS, WE DID NOT CARRY A MENTION IN THE
TAFS AT THIS TIME.
THE COLD WESTERLY FLOW COMBINED WITH ENOUGH MOISTURE TRAPPED
UNDER AN INVERSION IS HELPING TO PULL STRATOCUMULUS DOWN INTO
PARTS OF THE AREA. THIS IS EXPECTED TO CONTINUE WITH AT LEAST
BROKEN CEILINGS AROUND 4,000 FEET, MAINLY FROM THE KPHL METRO ON
NORTH AND WESTWARD. THE WINDS HAVE BEEN DECOUPLING SOME WITH GUSTS
DROPPING OFF AT SOME OF THE TERMINALS EARLY THIS MORNING. ALL OF
OUR TERMINALS ARE EXPECTED TO HAVE SOME GUSTS IN THE 20-25 KNOT
RANGE FOR AWHILE TODAY BEFORE SETTLING DOWN LATER IN THE AFTERNOON
AND TONIGHT. THE AFOREMENTIONED BOUNDARY SHOULD MAINTAIN SOME
STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS WITH IT AS IT DROPS
SOUTHWARD THROUGH THE EVENING. THIS BOUNDARY WILL ALSO TURN THE
SURFACE WINDS MORE TO THE NORTHWEST THROUGH TONIGHT.
OUTLOOK...
DRY WEATHER AND VFR CONDITIONS ARE FORECAST FOR SUNDAY AND
MONDAY. PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION FROM
THE WEST ON MONDAY NIGHT AND IT SHOULD CONTINUE INTO TUESDAY. THE
PRECIPITATION MAY BEGIN AS A WINTRY MIX ON MONDAY NIGHT AT KRDG,
KABE AND PERHAPS KTTN. ALL RAIN IS ANTICIPATED FOR KPHL, KPNE,
KILG, KMIV AND KACY.
A COLD FRONT IS EXPECTED TO PASS THROUGH OUR REGION ON TUESDAY
NIGHT, BRINGING AND END TO THE RAIN. HIGH PRESSURE AND DRY WEATHER
SHOULD FOLLOW FOR WEDNESDAY.
&&
.MARINE...
AN INTENSE SURFACE LOW OVER THE CANADIAN MARITIMES WILL CONTINUE
TO CIRCULATE A COLD AIR MASS OVER OUR REGION UNDER A WESTERLY FLOW.
A SECONDARY COLD FRONT WILL SWING AROUND THIS LOW AND SETTLE
SOUTHWARD ACROSS THE AREA TODAY INTO TONIGHT. SOME COLDER AIR WILL
ADVECT INTO THE AREA BEHIND THIS FRONT THROUGH TONIGHT. THE
PRESSURE GRADIENT REMAINS TIGHTENED TODAY INTO TONIGHT, HOWEVER
THE OVERALL WIND FIELD IS FORECAST TO LESSEN WITH TIME. THIS HAS
ALREADY BEEN NOTED AS THE WINDS HAVE BEEN GRADUALLY COMING DOWN
EARLY THIS MORNING. WHILE THERE COULD BE SOME UPTICK FOR A TIME
THIS MORNING DUE TO A LITTLE BETTER MIXING, IT MIGHT END UP BEING
A MORE MARGINAL SETUP FOR A SMALL CRAFT ADVISORY /ESPECIALLY
ACROSS THE SOUTHERN ZONES/. BASED ON THE SOUNDINGS AND TO ALLOW
FOR SOME WIGGLE ROOM, THE ADVISORY WILL RUN UNTIL 18Z FOR ALL
AREAS. THIS CAN ALWAYS BE CANCELLED EARLY. OTHERWISE, A DOWNWARD
TREND IN THE SEAS AND WINDS UNDER ADVISORY CRITERIA ARE EXPECTED
TONIGHT AS HIGH PRESSURE EDGES CLOSER.
WITH THE NORTHWEST FLOW PERSISTING INTO SUNDAY, WIND GUSTS TO
AROUND 25 KNOTS ARE POSSIBLE AT THAT TIME. HIGH PRESSURE SHOULD
BUILD ACROSS THE COASTAL WATERS OF NEW JERSEY AND DELAWARE ON
SUNDAY NIGHT AND EARLY MONDAY, BRINGING RELATIVELY TRANQUIL
CONDITIONS.
WIND SPEEDS ARE FORECAST TO BE ON THE INCREASE AGAIN LATE ON
MONDAY AS OUR NEXT WEATHER SYSTEM BEGINS TO APPROACH FROM THE
WEST. A BRISK SOUTHERLY FLOW IS ANTICIPATED FOR MONDAY NIGHT AND
TUESDAY WITH WIND GUSTS IN EXCESS OF 25 KNOTS, ALONG WITH WAVE
HEIGHTS ON OUR OCEAN WATERS BUILDING TO 5 TO 8 FEET.
A COLD FRONT IS EXPECTED TO PASS ACROSS THE REGION ON TUESDAY
NIGHT. THE WIND DIRECTION WILL LIKELY SHIFT TO THE WEST. HOWEVER,
GUSTS NEAR 25 KNOTS WILL REMAIN POSSIBLE INTO WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-
431-450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
335 AM EST Sat Jan 14 2012
.SYNOPSIS...
08Z water vapor and H4 RUC analysis shows an upper level pattern
consisting of longwave troughing over much of the inter-mountain
west, followed downstream by longwave troughing over much of the
CONUS east of the continental divide. A series of shortwaves
beginning to arrive along the British Columbia coastline will slowly
break down the western U.S. ridge during the upcoming weekend which
will lead to eventual height rises and an overall warmup for the
eastern states by the early portion of next week.
For now however, watching a shortwave impulse rounding the base of
the main eastern trough over the SE states early this morning. The
trough axis is just now exiting east of our area, seen with an
expanding area of subsidence/drying overhead on WV imagery. A final
piece of energy is sliding down the backside of the trough through
the mid-section of the country. This energy will slide to our north
tonight allowing height rises in its wake for Sunday.
At the surface, 1028mb high pressure centered along the TX/LA coasts
continues to build east into our forecast area. As the ridge expands
eastward, the local gradient has been slowly weakening allowing for
an increasingly efficient radiational cooling setup. Still
anticipate a widespread light freeze by sunrise away from the
immediate coast. A few isolated and normally colder locations may
still briefly reach hard freeze criteria in the hour or two
surrounding sunrise.
&&
.SHORT TERM (TODAY THROUGH MONDAY)...
Today,
Subsidence behind the departing shortwave this morning will help
promote mostly sunny skies through the day. However, a slight
re-enforcing shot of CAA...especially above the surface will keep
temperatures a bit below normal. At the surface, high pressure will
continue to expand eastward with a high center forming over the
coastal waters by the later afternoon/evening hours. To our north, a
weak surface reflection/low associated with the final shortwave
impulse will translate quickly from MO this afternoon, to the TN
valley this evening. Associated with this feature will be a weak
cold front that will cross northern AL/GA and into the Carolinas.
Although this cold front will not directly pass through our area, it
will have an influence of somewhat tightening the gradient over our
northern zones later today/this evening. The tighter gradient may
have an impact on temperatures tonight. Before that, afternoon temps
today are expected to top out in the mid/upper 50s.
Tonight,
As mentioned above, some uncertainly with regards to temperatures
relating to how rapidly the gradient will collapse again over our
northern/NE zones in the wake of a passing cold front/trough. The
impact looks to be least along and south of the I-10 corridor where
proximity to the eastward extension of the surface ridge should set
up good radiational cooling conditions early. The temperatures drop
may be slower this evening further to the north, however the
GFS/ECMWF both show a quick exit of the trough and the potential for
late night de-coupling. Therefore, will not deviate far from a
MET/MAV blend for overnight lows. Generally looking for lows in the
low/mid 30s inland and mid/upper 30s at the coast. Does appear that
any location which do reach or drop just below freezing will not do
so until right around sunrise, with a fairly short duration of near
freezing temps. If the tighter gradient holds longer than numerical
guidance currently suggest, then low temps would not be quite as
cold for areas north of KTLH and KVLD.
Sunday/Sunday night,
Very pleasant day upcoming for the second half of the weekend.
Rising heights over-top a strong surface ridge will provide the
region with dry and seasonable conditions. Winds will be on the
light side, which will slow the overall diurnal mixing, however
should still be able to reach afternoon highs very close to
climatology in the 59-64 range. Sunday night the surface ridge will
exit to our east allowing a slow increase in gradient and also low
level moisture. Current guidance still suggest a cool overnight with
lows in the mid 30s inland to the low 40s at the coast.
Monday,
Stacked ridging will allow temperatures to finally rise above
normal for most locations. Still not anticipating all that efficient
a mixing environment, and therefore will likely not realize the full
potential of the column that 850mb temps around 10C would suggest.
However, not too many will be complaining as temps rise into the
upper 60s to near 70 under partly sunny skies. The SE/S flow is
likely to keep immediate coastal areas a bit cooler, especially
along the Apalachee Bay coastline where shelf water temps are in
the upper 50s.
&&
.LONG TERM (TUESDAY THROUGH NEXT SATURDAY)...
The large scale longwave pattern commences fairly amplified. This is
highlighted in the Nrn stream by troughing across Plains and weak
ridging in between. Srn stream with weak troughing Desert SW and
weak ridging elsewhere. At surface, high along Carolina coast
ridging swwd into Cntrl Gulf. Low in Srn Great Lakes with cold front
Swwd across Wrn TN Valley and into TX.
During the rest of the period, Plains upper trough digs rapidly SEWD
accompanied by shortwave and merges with Desert SW Trough crossing
the Nrn Gulf Tues into Tues night. In response, Srn stream upper
ridge shunted offshore. At surface, this trough pushes surface low
to Srn Great Lakes kicking high further into Atlc. Assocd cold front
with limited instability dragged rapidly Sewd with deep sly flow
setup from Gulf. GFS and ECMWF similar in timing and intensity of
front, and about six hours slower than 24 hrs ago, pushing thru Wrn
CWA Tues night exiting Ern most zones Wed morning bringing sct shwrs
and possibly a few tstms.
Trough pushes into Atlc beginning Wed night. In its wake, NWLY
steering flow once again dominates local area as strong high builds
SEWD from Srn Plains spreading a reinforcing shot of cold and very
dry offshore air across local region Wed into late Thurs. However
coldest air remains well to our north so not expecting a solid
freeze event. By early Fri, models consistent with next albeit weak
shortwave that helps developing surface low which moves moves newd
into Lwr MS Valley dragging trailing cold front to Wrn Gulf.
Locally, this pushes the dry airmass EWD and high offshore
increasing onshore flow and clouds beginning Fri night.
Forecast will show low-mid sct pops Tues aftn especially NW third
expanding everywhere on Wed morning down to wdly sct-low sct Wed
aftn. Otherwise nil pops thru period. Ahead of the front min temps
will be around 10 degrees above climo Mon and Tues nights dropping
to at or below climo Wed night and may reach freezing in coldest
locales then inching to slightly above climo on Thu night. Max temps
commence at least 10 degrees above climo on Tues dropping to at or
slightly above climo on Wed then inching up to a few degrees each
day thru Fri. Average inland min/max temps are 39/62.
&&
.MARINE...
High pressure will build over the coastal waters today allowing
winds and seas to subside. A brief surge of westerly winds may
approach cautionary levels overnight into early Sunday morning
before quickly diminishing by the afternoon. The ridge of high
pressure will then move east of our region Sunday night allowing
winds to come around to the east and southeast and increase to
moderate levels for the early portion of next week. A weak cold
front is schedule to cross the northeast Gulf Tuesday night or
Wednesday with a shift back to offshore flow in its wake.
&&
.AVIATION (through 06Z Sunday)...
VFR Conditions with mainly clear skies through the period. Calm
winds increase to west to northwest around 5 mph after sunrise,
then calm again after sunset.
&&
.FIRE WEATHER...
Expect a faster warmup and higher afternoon temperatures today
compared to yesterday. Therefore with a persistent dry airmass
expect around 4 hour durations of RH below 25% in our Alabama and
Georgia zones, altho ern counties of GA iffy. But...with warning
already in effect will elect to keep it everywhere and have day
shift reevaluate. For our Florida zones, altho critical humidities
will be realized, latest dispersions as well as ERC and 20 foot
winds should remain under critical levels. Therefore inherited watch
has been discontinued. Airmass should moisten slightly on Sunday
precluding red flag conditions over AL/GA. Once again low humidities
in FL will be offset by ERC...dispersion and winds below critical
levels. Red flag conditions are not anticipated during the upcoming
work week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 57 32 62 33 68 / 0 0 0 0 0
Panama City 57 40 62 43 61 / 0 0 0 0 0
Dothan 59 35 59 36 69 / 0 0 0 0 0
Albany 57 32 59 34 70 / 0 0 0 0 0
Valdosta 56 33 60 35 68 / 0 0 0 0 0
Cross City 58 31 64 34 70 / 0 0 0 0 0
Apalachicola 56 36 61 41 60 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Red Flag Warning from Noon today to 5 PM CST this afternoon for
Coffee-Dale-Geneva-Henry-Houston.
GA...Red Flag Warning from 1 PM this afternoon to 6 PM EST this
evening for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-
Colquitt-Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier-
Lee-Lowndes-Miller-Mitchell-Quitman-Randolph-Seminole-
Terrell-Thomas-Tift-Turner-Worth.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
236 AM CST SAT JAN 14 2012
.DISCUSSION...
ISSUED 235 AM CST SAT JAN 14 2012
LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND
CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS
BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY
TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE
WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY.
HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO
IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS
SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST
MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN
SHEARING OUT OVER THE CENTRAL PLAINS.
PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES
TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY.
SHORT TERM...TODAY THROUGH TUESDAY...
SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST
NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE
SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE
WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH
THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT
QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A
GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS
INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND
KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER
CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH.
SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY
TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO
FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON
THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH
MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL
INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS
BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING
THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY
NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A
QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT
MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH
OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY
THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE
TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL
CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH
THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF
THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL
CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT
CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES
SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER
SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS
KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE
WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN
THE PERIOD.
GEELHART
&&
.AVIATION...
ISSUED 1116 PM CST FRI JAN 13 2012
LOW CLOUDS/FLURRIES HAVE CLEARED THE TAF SITES EXPECT FOR BMI AND
CMI...AND THESE SITES SHOULD CLEAR OUT IN THE NEXT HOUR OR SO. OUT
WEST...THE NEXT CLIPPER IS ALREADY SPREADING CLOUDS AND SOME RADAR
RETURNS ACROSS THE WESTERN HALF OF IA AND NORTHWESTERN MO. THE
SURFACE REFLECTION NOW OVER EASTERN NEB WILL MOVE ALONG THE LOW
LEVEL BAROCLINIC ZONE FROM MORTHWEST TO SOUTHEAST ACROSS MO THEN TO
MIDDLE TN BY 00Z SUN. ALTHOUGH THE SHORT RANGE MODELS MOSTLY KEEP
THE LIGHT SNOW WITH THIS SYSTEM TO THE SOUTHWEST OF SPI...IT WILL BE
A CLOSE ENOUGH SHAVE TO CONTINUE WITH VCSH THERE AROUND 12Z-18Z.
WILL KEEP OTHER TERMINALS DRY WITH JUST SOME SCATTERED STRATOCU AND
BROKEN MID/HIGH CLOUDS. AN UPPER SHEAR AXIS EXTENDS BACK FROM THE
NEB CLIPPER TO NORTHERN ND...WHICH WILL TAKE A MORE NORTHERLY TRACK
ACROSS THE LOWER GREAT LAKES WITH LITTLE SURFACE REFLECTION. MID
LEVEL LIFT/FRONTOGENESIS IS FORECAST TO BRUSH NORTHERN IL AFTER 00Z
SUN...BUT MOST OF THE PRECIPITATION SHOULD BE TO THE NORTH OF
PIA/BMI. SURFACE WINDS THIS PERIOD WILL BE QUITE VARIABLE...BUT LESS
THAN 10 KT MOST OF THE TIME AS THE SURFACE LOW MOVES SOUTH OF THE
AREA AND A WEAK PRESSURE GRADIENT PREVAILS TO THE NORTH.
04
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1106 PM CST FRI JAN 13 2012
.AVIATION...
THE SMALL LOW PRESSURE SYSTEM THAT WAS EXPECTED TO BRING LIGHT
SNOW AND MVFR CIGS TO THE AREA TOMORROW NO LONGER SEEMS TO BE A
THREAT AS IT PASSES MAINLY OVER WESTERN IOWA. THE ONLY REAL THREAT
FOR THESE CONDITIONS NOW SEEMS TO BE TOWARDS 00Z IN NORTHEAST
IOWA...BUT THAT THREAT SEEMS VERY LOW RIGHT NOW. THUS LIGHT WINDS
AND VFR WEATHER SHOULD PERSIST AT ALL SITES THROUGH 06Z/15. ALL
CIGS TODAY SHOULD BE 5000 TO 8000 FT.
&&
.PREV DISCUSSION... /ISSUED 327 PM CST FRI JAN 13 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS AN EXTRATROPICAL CYCLONE IN SOUTHEAST CANADA
WITH NUMEROUS TROFS FROM THE TENNESSEE VALLEY BACK INTO THE UPPER
MIDWEST. RADAR TRENDS THROUGH MID AFTERNOON CONTINUE TO SHOW PLENTY
OF FLURRIES AND LIGHT SNOW OVER THE MID MISSISSIPPI VALLEY. CLEARING
UNDER THE CYCLONIC FLOW WAS MAKING SLOW BUT STEADY PROGRESS EASTWARD.
18Z SFC ANALYSIS HAS A COLD FRONT FROM THE EASTERN GREAT LAKES BACK
INTO NORTHEAST ILLINOIS WITH A HIGH PRESSURE RIDGE FROM MINNESOTA
INTO EASTERN TEXAS. A CHINOOK WARM FRONT WAS OVER THE EASTERN PARTS
OF THE DAKOTAS AND NEBRASKA. A WARM FRONT ASSOCIATED WITH THE NEXT
CLIPPER SYSTEM WAS MOVING OUT OF THE NORTHERN ROCKIES. DEW POINTS
UNDER THE HIGH PRESSURE RIDGE WERE IN THE SINGLE DIGITS ABOVE AND
BELOW ZERO. OTHERWISE DEW POINTS WERE IN THE TEENS AND 20S ACROSS
THE MIDWEST AND PLAINS.
SHORT TERM...TONIGHT AND SATURDAY...
LIGHT SNOW WILL CONTINUE THROUGH LATE AFTERNOON BUT WILL TAPER TO
FLURRIES ONCE SUNSET OCCURS. RUC TRENDS CONTINUE TO SHOW WEAK F
VECTOR CONVERGENCE AND WEAK FRONTOGENETICAL FORCING WILL REMAIN
ACROSS THE AREA INTO THE EARLY EVENING. THAT COMBINED WITH THE
SHALLOW ARCTIC AIR MASS AND A VORT MAX MOVING THROUGH THE CWFA WILL
ALLOW FLURRIES TO PERSIST THROUGH MID EVENING.
CLEARING WILL OCCUR FROM WEST TO EAST DURING THE EVENING AND
OVERNIGHT HOURS. TEMPERATURES SHOULD DROP QUICKLY ONCE CLEARING
OCCURS DUE TO THE SNOW COVER AND LIGHT WINDS. AFTER MIDNIGHT...WAA
CLOUDS FROM THE APPROACHING CLIPPER SYSTEM WILL MOVE INTO THE AREA
AND LIKELY ALLOW TEMPERATURES TO BOTTOM OUT AND SLOWLY RISE.
AFTER 3 AM...ALL MODELS SHOW F VECTOR CONVERGENCE DEVELOPING AGAIN
WITH COLLAPSING CONDENSATION PRESSURE DEFICITS ALONG WITH AN
INCREASE IN FRONTOGENETICAL FORCING. MOISTURE WITH THIS CLIPPER
SYSTEM IS LIMITED BUT FLURRIES AND LIGHT SNOW SHOULD BREAK OUT PRIOR
TO DAWN GENERALLY WEST OF A KIIB TO KPPQ LINE. SCHC/CHC POPS WERE
DONE DUE TO THE LIMITED MOISTURE BUT MAY NEED TO BE RAISED IN THE
EXTREME WEST AND SOUTHWEST PARTS OF THE CWFA.
THE WAA PRECIPITATION WING OF THE CLIPPER SYSTEM WILL MOVE ACROSS
THE WESTERN HALF OR TWO THIRDS OF THE CWFA SATURDAY MORNING.
CONDENSATION PRESSURE DEFICITS REMAIN LOW AND THERE IS F VECTOR
CONVERGENCE WITH SOME FORCING. DURING THE AFTERNOON THE COLD
CONVEYOR BELT PRECIPITATION FROM THE CLIPPER SYSTEM WILL OVERSPREAD
THE ENTIRE AREA BEFORE ENDING FROM THE WEST LATE IN THE AFTERNOON.
AS FOR AMOUNTS...A DUSTING OF ACCUMULATION IS POSSIBLE PRIOR TO
SUNRISE IN THE FAR WEST/SOUTHWEST PARTS OF THE CWFA. ACCUMULATIONS
DURING THE DAY SATURDAY SHOULD RANGE FROM A DUSTING TO ONE HALF
INCH. IT IS CONCEIVABLE THAT ACCUMULATIONS APPROACHING AN INCH MAY
OCCUR OVER THE SOUTHWEST THIRD TO HALF OF THE CWFA. ..08..
LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
ACTIVE/UNSETTLED PATTERN TO PERSIST THROUGH THE PERIOD WITH MANY FCST
CHALLENGES. MAIN STORM SYSTEM THAT BEARS CONSIDERABLE WATCHING IS IN
MON-TUE TIME-FRAME. THIS STORM LOOKS TO BRING WINTRY MIX OF PCPN WITH
POTENTIAL FOR HEADLINES.
SAT NGT... SOME RESIDUAL WEAK LIFT LINGERS INTO THE EVE ACROSS THE NORTH
AS CLIPPER DEPARTS AND WARM FRONT PUSHES THROUGH. NAM AND GFS
BUFR SOUNDINGS SHOW LOSS OF ICE INTRODUCTION WHICH WOULD SUPPORT DRIZZLE
OR FREEZING DRIZZLE. CONCERNS THOUGH THESE MODELS MAY BE OVERDONE WITH
EXTENT OF LOW LEVEL MOISTURE ... A TYPICAL BIAS ESPECIALLY WITH
NAM... ESPECIALLY GIVEN NO SNOW MELT. GIVEN UNCERTAINTIES AND WITH
ANY PCPN JUST TRACE AMOUNTS HAVE LEFT OUT ANY MENTION ATTIM. MAY SEE
TEMPS STEADY OR RISING OVRNGT ESPECIALLY SOUTH WITH ONSET OF LOW LEVEL
WARM ADVECTION.
SUN-SUN NGT... NEXT ARCTIC FRONT TO EMERGE INTO THE PLAINS AND EXPECTED
TO PUSH THROUGH IA AND POSSIBLY BISECTING 12Z MON PER NAM/GFS. HI-RES
ECMWF SLOWER BUT 12Z RUN IS SLIGHTLY FASTER AND MAY BE TRENDING TOWARD
NAM/GFS. DEEPER MOISTURE RETURNS LATE FOR POSSIBLY SOME VERY LIGHT RAIN
OR DRIZZLE AFTER MIDNIGHT... OR VERY LIGHT FREEZING RAIN/DRIZZLE IN SOME
AREAS DEPENDING ON SFC TEMPS WITH NW CWA MOST SUSCEPTIBLE IT APPEARS
ATTIM BUT THIS DEPENDENT ON FRONTAL TIMING. MOST IF NOT ALL OF
AREA SHOULD GET ABOVE FREEZING WITH 40S WIDESPREAD ACROSS THE SW CWA ON
GUSTY SOUTHERLY WINDS.
MON-TUE... STRONG BAROCLINICITY AND COUPLED JET STRUCTURE SUPPORT
CYCLOGENESIS ALONG ARCTIC FRONT... WITH CONSIDERABLE MODEL SPREAD ON
MAGNITUDE/TRACK/TIMING... AND GIVEN HIGHLY DYNAMICAL ENVIRONMENT EXPECT
CONTINUED CHANGES IN MODELS NEXT DAY OR TWO. GFS AND HI-RES ECMWF HAVE
TRENDED DEEPER AND SLOWER... AND MAY CONTINUE TO SEE THIS TREND. BOTTOM
LINE IS MOISTURE AND FORCING SUPPORTS MODERATE QPF EVENT NOT TOO
DISSIMILAR FROM THIS MOST RECENT EVENT. DEPENDING ON FRONT AND SFC LOW
LOCATIONS PCPN TYPES COULD VARY OR TRANSITION FROM RAIN TO FREEZING
RAIN...SLEET AND SNOW ACROSS CWA. THEREFORE... WITH THE WINTRY MIXTURE
THIS SYSTEM WILL BEAR CONSIDERABLE WATCHING IN THE DAYS AHEAD. POPS ARE
IN MOD/HIGH CHC CATEGORY FOR NOW GIVEN UNCERTAINTY WITH TRACK. IN
ADDITION MAY SEE FOG MON WITH AREAS OF DENSE FOG AHEAD OF SFC LOW WITHIN
LOW LEVEL MOISTURE CONVERGENCE.
WED-FRI... MUCH COLDER WITH ANOTHER ARCTIC FRONT SUGGESTED TO ARRIVE
WED THAT MAY NEED POPS IN LATER FCSTS. FOR NOW THOUGH HAVE CHC POPS
THU-FRI AS ENERGY RIPPLES ALONG LOW-MID LEVEL BAROCLINIC ZONE. WINTER HAS
FINALLY ARRIVED. ..05..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
331 AM CST SAT JAN 14 2012
.DISCUSSION...
SHORT RANGE (TODAY AND SUNDAY)...
09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD
UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A
STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN
THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL PLAINS.
WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH EMBEDDED WITHIN
THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT EXPECT TO SEE MANY
EFFECTS FROM THIS WAVE SHORT OF SOME PASSING LOW TO MID CLOUDS
EARLY THIS MORNING. BY MID MORNING TO EARLY AFTERNOON THE WAVE WILL MOVE
THROUGH THE AREA AND SUBSIDENCE WILL TAKE OVER BRINGING MOSTLY CLEAR
CONDITIONS. AT THE SURFACE A FAIRLY STRONG RIDGE HAS SET UP IN THE
WESTERN HIGH PLAINS AND HAS CREATED A DECENT PRESSURE GRADIENT
BETWEEN ITSELF AND A WEAK SURFACE TROUGH WHICH IS CURRENTLY
LOCATED IN FAR SE NEBRASKA. AS A RESULT OF THE GRADIENT BETWEEN
THESE TWO FEATURES EXPECT WEST-NORTHWEST WINDS TO PICK UP IN
INTENSITY THROUGHOUT THE DAY LENDING TO SOME WEAK COLD AIR
ADVECTION. HOWEVER WITH LOWS STARTING OUT A BIT WARMER THAN
YESTERDAY AND WITH GOOD INSOLATION EXPECT TEMPS TO CREEP INTO THE
UPPER 40S AND LOWER 50S ACROSS NORTHEAST KANSAS FOR TODAY. BUMPED
MIN TEMPS FOR SUNDAY UPWARD A LITTLE AS WINDS BACK AROUND TO THE
WEST-SOUTHWEST OVERNIGHT AND PICK UP EARLY SUNDAY
MORNING...CREATING SOME WEAK WARM AIR ADVECTION AND KEEPING TEMPS
A BIT WARMER. SUNDAY WILL LIKELY BE THE NICEST DAY OF THE FORECAST
PERIOD...AS STRONG SOUTHERLY WINDS AND A FLEETING UPPER RIDGE
PUSHES THROUGH THE AREA. GIVEN THOSE TWO FACTORS AS WELL AS GOOD
INSOLATION DUE TO CLEAR SKIES EXPECT TEMPS TO REACH INTO THE LOWER
60S ON SUNDAY.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)...
THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES
INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS AHEAD
OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE COULD HAVE
ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS ON MONDAY
COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD FRONT TO BE
SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY MEANING AREAS NORTH
AND WEST OF THE TURNPIKE WILL LIKELY ONLY RISE INTO THE 40S ON
MONDAY. A QUICKLY MOVING UPPER WAVE WILL ALSO PUSH THROUGH THE
NORTHERN PLAINS ON MONDAY NIGHT...AND PERHAPS COULD BRING A PERIOD
OF VERY LIGHT SNOW TO AREAS NORTH OF HIGHWAY 24 ON MONDAY NIGHT.
WITH NOT MUCH MOISTURE TO WORK WITH DO NOT EXPECT MORE THAN A TENTH
OR TWO OF SNOW ACCUMULATION FROM THIS SYSTEM. TUESDAY WILL BE
RATHER CHILLY AS THE ARCTIC AIRMASS TAKES HOLD OF THE AREA...BUT BY
WEDNESDAY WEST-SOUTHWEST WINDS WILL RETURN TO THE AREA BRINGING
ANOTHER GENTLE WARM UP. MODELS THEN HINT AT FRIDAY BEING ANOTHER
UNSEASONABLY WARM DAY. SOUTH-SOUTHWEST WINDS WITH A VERY WARM
AIRMASS LOOK TO MAKE THEIR WAY INTO NORTHEAST KANSAS ON FRIDAY.
WILL CURRENTLY STICK WITH TEMPS IN THE UPPER 40S TO LOWER 50S FOR
FRIDAY...BUT IF MODELS CONTINUE TO TREND TOWARD A WARMER SOLUTION
WILL BUMP THOSE TEMPS UP AS THAT DAY APPROACHES.
JL
&&
.AVIATION...
WIND FORECAST REMAINS THE BIGGEST CHALLENGE WITH VFR CONDITIONS
STILL EXPECTED. LOW PRESSURE TO MOVE SOUTHEAST THROUGH EASTERN
NEBRASKA AND NORTHERN MISSOURI THROUGH 15Z WITH WINDS SHIFTING AS
A RESULT. BACKED OFF THE NORTHWEST WIND TIMING A BIT WITH MIXING
INTO THE DEEPER WINDS HOLDING OFF A BIT. WINDS COME BACK TO LIGHT
SOUTHERLY IN THE 20Z-03Z PERIOD.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1022 PM MST FRI JAN 13 2012
.UPDATE...
646 PM MST FRI JAN 13 2012
LATEST RUC AND HRRR CATCHING INCOMING SURFACE TROUGH FROM THE
NORTHWEST. THEY HAD THE STRENGTH/POSITION THE BEST WITH THE
REMAINING MODEL OUTPUT NOT STRONG ENOUGH. SO INCREASED WIND SPEEDS
OVER THE NORTHEAST PORTION OF THE AREA A LITTLE. ALSO BECAUSE OF
THE STRONGER WINDS RAISED THE MINS SOME THAT SAME AREA AS WELL.
OTHERWISE...JUST ADJUSTED HOURLY GRIDS.
BULLER
&&
.DISCUSSION...
208 PM MST FRI JAN 13 2012
TONIGHT...SHOULD SEE NORTHWEST WINDS OF 10 TO 20 MPH WINDS WITH
HIGHER GUSTS THROUGH MIDNIGHT BEHIND A DEPARTING UPPER LEVEL
DISTURBANCE. AFTER MIDNIGHT WINDS SUBSIDE A BIT INTO THE 10 MPH
RANGE. OVERNIGHT LOWS WILL BE A BIT WARMER THEN THE PAST FEW NIGHTS
AS WARM AIR ALOFT MOVES IN. WILL AIM FOR LOWS GENERALLY IN THE UPPER
TEENS TO LOW 20S IN FAR EASTERN COLORADO...LOW TO MID 20S EAST OF
THE CO/KS BORDER. THIS IS SEVERAL DEGREES WARMER THAN THE MAV AND
MET MOS GUIDANCE.
007
SATURDAY-SUNDAY...H5 RIDGE CONTINUES TO BUILD EAST TOWARDS CWA...WITH
DRY/STABLE AIR MASS IN PLACE THROUGH SUNDAY NIGHT. TEMPERATURES
WILL CONTINUE TO MODERATE OVER THE NEXT FEW DAYS...WITH HIGH TEMPS
IN THE 50S SATURDAY...AND MID/UPPER 50S ON SUNDAY. CONSIDERING
TEMPS ALOFT SAT/SUN NIGHTS...BUMPED LOWS TO THE UPPER 20S. THIS IS
ABOUT 5-10F ABOVE MOS GUIDANCE...HOWEVER CONSIDERING TEMPS ALOFT
AND POSSIBLE SKY COVER SUN NIGHT...THIS MAY STILL BE TOO COOL.
MONDAY-MONDAY NIGHT...TROUGH DEVELOPING OVER THE PACIFIC NW OVER THE
WEEKEND WILL PROGRESS EAST ACROSS THE GREAT BASIN TOWARDS THE CWA
MONDAY. GUIDANCE STILL DIFFERS BY ABOUT 6HR ON TIMING OF ASSOCIATED
COLD FRONT MONDAY...HOWEVER OVERALL TREND HAS BEEN TO SPEED UP
ARRIVAL...WITH FRONTAL PASSAGE LIKELY BY MIDDAY. PRECIP ASSOCIATED WITH
LARGE SCALE ASCENT ALONG LEADING EDGE OF TROUGH AXIS LOOKS TO ARRIVE
FROM THE NW LATE MONDAY AFTERNOON...QUICKLY MOVING EAST THROUGH THE
EVENING HOURS. GUIDANCE IN GOOD AGREEMENT ON STABLE/DRY AIR QUICKLY
MOVING IN AFTER 06Z...SO I TRENDED FORECAST IN THAT DIRECTION. I
KEPT BEST CHANCES DURING THE EVENING IN THE NORTH...AND LEFT A SMALL
AREA OF SLIGHT CHANCE POPS IN THE FAR EAST AFTER 06Z. CONSIDERING
LIMITED MOISTURE AND QUICK NATURE OF THIS SYSTEM...ONLY ANTICIPATING
LIGHT SNOW ACCUMULATIONS...ABOUT AN INCH OR LESS.
TUESDAY-FRIDAY...REMAINING FORECAST LOOKS DRY WITH W/NW FLOW
DEVELOPING ACROSS WESTERN CONUS...AND DRY/STABLE AIR MASS IN PLACE.
BIGGEST QUESTION THROUGH THESE PERIODS WILL BE HOW QUICKLY SHALLOW
COLD AIR MASS MODERATES...AND WHAT TEMPS WILL DO IN RESPONSE TO WEAK
SHORTWAVE TROUGHS EMBEDDED WITHIN MEAN FLOW. FOR NOW EXPECT BELOW
NORMAL TEMPS TUESDAY AND NEAR NORMAL TEMPS WEDNESDAY. GUIDANCE STILL
INDICATING RISING H5 HEIGHTS H85 TEMPS TO ABOUT 10-12C BY
FRIDAY...WHEN I KEPT FORECAST OF MID 50S IN THE WEST. THIS MAY END
UP BEING TOO COOL CONSIDERING CONDITIONS ALOFT...HOWEVER THERE IS
ENOUGH UNCERTAINTY IN REGARDS TO BOUNDARY LAYER DIFFERENCES TO
KEEP ME FROM CHANGING TOO MUCH THIS FAR OUT.
DR
&&
.AVIATION...
1020 PM MST FRI JAN 13 2012
FOR THE 06Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
SURFACE TROUGH WILL MOVE THROUGH THE AREA TONIGHT AND CAUSE SOME
GUSTY WINDS...MAINLY AT KMCK. AFTER THAT...WINDS WILL GRADUALLY
SHIFT THROUGH THE PERIOD AS THE SURFACE RIDGE MOVES EAST AND THE
LEE TROUGH DEVELOPS.
BULLER
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
127 AM CST SAT JAN 14 2012
.DISCUSSION...
HAVE UPDATED FORECAST THIS MORNING FOR PRECIP TRENDS AS WELL AS
TEMPERATURES. SHORTWAVE DIVING OUT OF THE DAKOTAS INTO CENTRAL NEB
IS INDUCING FLURRIES OR LIGHT SNOW IN SOUTHEAST SD TO
NORTHWEST/CENTRAL IA. NORTHWESTERLY FETCH OF AREAS OF SNOW HAS
BEEN SKIRTING THE FRINGE OF THE CWA...AND OBS HAVE INDICATED NO
VIS REDUCTIONS WITHIN THE CWA...WITH YKN AND DNS THE CLOSEST
LOCATIONS RECEIVING ENOUGH LIGHT SNOW TO LOWER VIS. HAVE PULLED
DOWN POPS SIGNIFICANTLY AWAY FROM THE NORTHERN AND EASTERN MARGINS
OF THE CWA THIS MORNING...WITH JUST FLURRIES AFTER 09Z. ALSO
TWEAKED TEMPERATURE CURVE THROUGH THE MORNING HOURS AS
TEMPERATURES ARE BEGINNING TO RISE IN THE WESTERN CWA ON THE NOSE
OF HIGHER WESTERLY WINDS.
MAYES
&&
.PREV DISCUSSION... /ISSUED 1124 PM CST FRI JAN 13 2012/
AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
SURFACE LOW WAS DEEPENING/ORGANIZING JUST SW OF KOFK AT 14/05Z.
THIS LOW SHOULD TRACK SW OF KOMA AND INTO NW MO BY 12Z THEN
QUICKLY INTO SE MO BY SATURDAY AFTERNOON. LOW WILL SPREAD GUSTY NW
SURFACE WINDS TO TAF SITES BY MORNING...ALTHOUGH STRONGEST COULD
REMAIN JUST TO THE WEST. LOW CLOUDS AND LIGHT SNOW E THROUGH NE OF
LOW AT 14/04Z SHOULD STAY MOSTLY NE OF TAF SITES UNTIL AFTER LOW
PASSES TO THE SOUTH THEN A PERIOD OF MVFR CIGS ALONG WITH SNOW WAS
FORECAST AT KOFK AND KOMA WITH JUST THE LOW CLOUD MENTION AT
KLNK. CONFIDENCE IN SNOW REACHING TAF SITES WAS NOT HIGH. LOW
LEVEL DRY AIR WAS A NEGATIVE AND SNOW WAS HAVING A HARD TIME
WORKING S INTO NERN NEBRASKA BEFORE TAF ISSUANCE. OTHERWISE SKIES
SHOULD CLEAR BY LATE MORNING/EARLY AFTERNOON AND WINDS WILL BEGIN
DECREASING LATER IN THE AFTERNOON BEFORE TURNING S/SW AHEAD OF
ANOTHER SYSTEM BEGINNING TO DROP INTO SRN CANADA.
CHERMOK
PREV DISCUSSION... /ISSUED 342 PM CST FRI JAN 13 2012/
SHORT TERM...TONIGHT THROUGH MONDAY.
THE PRIMARY CONCERNS IN THE SHORT TERM WILL THE HOW FAR SOUTHWEST
TO CARRY THE LIGHT SNOW AND FLURRIES OVERNIGHT AND EARLY
SATURDAY...TEMPERATURES SATURDAY AND SUNDAY...HOW FAR NORTH WILL
THE LIGHT RAIN AND DRIZZLE MAKE IT MONDAY MORNING...AND LIGHT SNOW
MOVING IN FROM THE WEST MONDAY.
AT 18Z...LIGHT SNOW RETURNS HAVE SPREAD INTO PARTS OF MT AND BY
20Z GGW WAS DOWN TO 1/2SM IN SNOW. SINCE THE OPERATIONAL MODELS
WERE ALL DRY AT THAT TIME IN MT...NOT REAL CONFIDENT IN HOW THEY
ARE HANDLING THIS SYSTEM. THE SHORTWAVE TROF OVER THE WRN DAKOTAS
IS FORECAST TO QUICKLY DROP SOUTHEAST OVERNIGHT INTO MISSOURI BY
12Z. THIS WITH WAA...UPWARD VERTICAL MOTION WITH THE WAVE...AND
POTENTIAL VORTICITY ADVECTION. THE 12Z/18Z CONTINUED DRY EXCEPT
FOR HARRISON CO IN IOWA. THE GFS HAS SOME LIGHT PRECIPITATION
MAKING IT INTO NORTHEAST NEB WHILE THE 00Z/12 EC/12Z 4KM WRF AND
THE LATEST HRRR ARE A BIT STRONGER WITH THE WAVE IN GENERATING
LIGHT SNOW FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. ALTHOUGH
THERE ARE QUITE A FEW RETURNS SHOWING UP AT 21Z...SFC REPORTS ARE
STILL SPARSE IN REPORTING THE SNOW. LOOKING AT THE FORCING...
SATURATION...AND COLDEST TEMPS HAVE INCLUDED SOME SLIGHT CHC TO
CHC POPS OVER ESPECIALLY THE NORTHEASTERN THIRD OF THE CWA. AT
THIS TIME ONLY ADDED SOME VERY LIGHT AMOUNTS TO THE NORTHEAST.
ALTHOUGH SURFACE DEWPOINTS ARE VERY LOW (BELOW ZERO WRN IA AND THE
ALONG THE MISSOURI RIVER)...LOOK FOR THEM TO INCREASE OVERNIGHT
INTO THE TEENS AND 20S. WITH A SURFACE LOW TRACKING ACROSS THE
AREA OVERNIGHT...TEMPERATURES WILL BE TRICKY...FALLING OFF QUICKLY
TONIGHT IN WRN IOWA...BUT BEING HELD UP ACRS THE WRN CWA.
MID LEVEL RIDGING WILL BUILD IN FOR THE WEEKEND. WARMER
TEMPERATURES ARE FORECAST FOR WEEKEND WITH 50S FOR SUNDAY. THE
NEXT COLD FRONT MOVES THROUGH OVERNIGHT SUNDAY AND LOW CLOUDS AND
SOME DRIZZLE COULD DEVELOP IN SOUTHWEST IOWA. COLDER AIR WILL
RETURN FOR MONDAY WITH LIGHT SNOW DEVELOPING OVER SOUTH DAKOTA AND
WESTERN AND CENTRAL NEBRASKA. THIS LIGHT SNOW COULD START TO MAKE
IT INTO PARTS OF THE WESTERN FORECAST AREA BY DAY/S END.
ZAPOTOCNY
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
MODELS CERTAINLY DIVERGE REGARDING THE AMOUNT AND INTENSITY OF COLD
AIR PLUNGING INTO THE PLAINS BY MID TO LATE WEEK. THE OPERATIONAL
GFS HAS REMAINED THE COLDEST OF THE MEDIUM RANGE MODELS...WITH ECMWF
THE WARMEST. GFS ENSEMBLE MEMBERS OFFER NO HELP AS THE SPREAD IS
WIDE HERE TOO. IN FACT...THE 00Z ENSEMBLE TEMPERATURES FOR THURSDAY
HIGHS RANGED FROM 21 TO 49 AT OMAHA.
LEADING UP TO THIS TIME PERIOD...A SIMILAR EVOLUTION OF THE UPPER
FLOW PATTERN IS NOTED BY GFS/ECMWF. BOTH SHOW A BROAD TROUGH OVER
THE CENTER OF THE COUNTRY WITH A SHORTWAVE MOVING THROUGH NEBRASKA
AND IOWA MONDAY NIGHT AND TUESDAY. AND BOTH MODELS BREAK OUT LIGHT
SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS NORTHERN NEBRASKA INTO
NORTHERN IOWA. OUR CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST
MONDAY NIGHT...SO LEFT THAT UNCHANGED. HOWEVER...SLIGHTLY SLOWER
ECMWF KEEPS SNOW IN FOR TUESDAY. IF THIS OCCURS IT SHOULD ONLY
AFFECT OUR EAST AND SHOULD BE ENDING QUICKLY IN THE MORNING.
THEN UPPER PATTERN BEGINS TO FLATTEN OUT SOME...WITH NORTHWEST FLOW
THE CONSENSUS FOR WEDNESDAY. HIGHS IN THE 20S TUESDAY IN COOL
ADVECTION REGIME WILL WARM INTO THE 30S WEDNESDAY.
THURSDAY IS THE BIG QUESTION MARK AS THE GFS CONTINUES TO SHOW
STRONG BAROCLINIC ZONE DROPPING THROUGH THE CWA WHILE ECMWF KEEPS
BRUNT OF COLD AIR TO OUR NORTHEAST. DURING NORMAL WINTERS WOULD
EXPECT THE GFS AND COLD AIR TO WIN OUT...BUT THIS HAS BEEN ANYTHING
BUT A NORMAL WINTER. WE HAVE SEEN THESE SCENARIOS ADVERTISED AT DAYS
6 AND 7 BEFORE...AND TRENDING TOWARD WARMER SOLUTIONS HAS BEEN BEST.
ESPECIALLY WITH LIMITED SNOW COVER TO OUR NORTH. BOTH SIDES OF THE
ARGUMENT HAVE MERIT...SO TO STAY CONSISTENT WITH CURRENT
FORECAST...SURROUNDING OFFICES AND WIDELY DIVERGENT MODELS...WILL
HAVE TO KEEP TEMPERATURES CLOSE TO WHAT WE CURRENTLY HAVE GOING WITH
HIGHS IN THE 20S AND LOWER 30S. WHATEVER THE CASE...EXPECT A LITTLE
WARMER CONDITIONS ON FRIDAY AS RETURN FLOW SETS UP. MAY ALSO SEE
SOME LIGHT SNOW WITH THIS SCENARIO.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1124 PM CST FRI JAN 13 2012
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
SURFACE LOW WAS DEEPENING/ORGANIZING JUST SW OF KOFK AT 14/05Z.
THIS LOW SHOULD TRACK SW OF KOMA AND INTO NW MO BY 12Z THEN
QUICKLY INTO SE MO BY SATURDAY AFTERNOON. LOW WILL SPREAD GUSTY NW
SURFACE WINDS TO TAF SITES BY MORNING...ALTHOUGH STRONGEST COULD
REMAIN JUST TO THE WEST. LOW CLOUDS AND LIGHT SNOW E THROUGH NE OF
LOW AT 14/04Z SHOULD STAY MOSTLY NE OF TAF SITES UNTIL AFTER LOW
PASSES TO THE SOUTH THEN A PERIOD OF MVFR CIGS ALONG WITH SNOW WAS
FORECAST AT KOFK AND KOMA WITH JUST THE LOW CLOUD MENTION AT
KLNK. CONFIDENCE IN SNOW REACHING TAF SITES WAS NOT HIGH. LOW
LEVEL DRY AIR WAS A NEGATIVE AND SNOW WAS HAVING A HARD TIME
WORKING S INTO NERN NEBRASKA BEFORE TAF ISSUANCE. OTHERWISE SKIES
SHOULD CLEAR BY LATE MORNING/EARLY AFTERNOON AND WINDS WILL BEGIN
DECREASING LATER IN THE AFTERNOON BEFORE TURNING S/SW AHEAD OF
ANOTHER SYSTEM BEGINNING TO DROP INTO SRN CANADA.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 521 PM CST FRI JAN 13 2012/
AVIATION...
00Z TAFS FOR KOFK...KOMA AND KLNK.
CLIPPER-TYPE SYSTEM SHOULD MOVE QUICKLY INTO NERN NEBRASKA AROUND
14/06Z AND THEN INTO SERN MO BY 14/18Z. THIS SYSTEM WILL BRING A
SHIFT TO GUSTY NORTHWEST WINDS LATE TONIGHT/EARLY SATURDAY...
AND POSSIBLY A PERIOD OF LOWER CLOUDS AND SCATTERED SNOW SHOWERS.
SNOW CHCS APPEARED SOMEWHAT BETTER AT KOFK AND KOMA. SURFACE WINDS
SHOULD RELAX SATURDAY AFTERNOON BEFORE TURNING TO S/SW IN THE
EVENING AHEAD OF YET ANOTHER SYSTEM.
CHERMOK
PREV DISCUSSION... /ISSUED 342 PM CST FRI JAN 13 2012/
SHORT TERM...TONIGHT THROUGH MONDAY.
THE PRIMARY CONCERNS IN THE SHORT TERM WILL THE HOW FAR SOUTHWEST
TO CARRY THE LIGHT SNOW AND FLURRIES OVERNIGHT AND EARLY
SATURDAY...TEMPERATURES SATURDAY AND SUNDAY...HOW FAR NORTH WILL
THE LIGHT RAIN AND DRIZZLE MAKE IT MONDAY MORNING...AND LIGHT SNOW
MOVING IN FROM THE WEST MONDAY.
AT 18Z...LIGHT SNOW RETURNS HAVE SPREAD INTO PARTS OF MT AND BY
20Z GGW WAS DOWN TO 1/2SM IN SNOW. SINCE THE OPERATIONAL MODELS
WERE ALL DRY AT THAT TIME IN MT...NOT REAL CONFIDENT IN HOW THEY
ARE HANDLING THIS SYSTEM. THE SHORTWAVE TROF OVER THE WRN DAKOTAS
IS FORECAST TO QUICKLY DROP SOUTHEAST OVERNIGHT INTO MISSOURI BY
12Z. THIS WITH WAA...UPWARD VERTICAL MOTION WITH THE WAVE...AND
POTENTIAL VORTICITY ADVECTION. THE 12Z/18Z CONTINUED DRY EXCEPT
FOR HARRISON CO IN IOWA. THE GFS HAS SOME LIGHT PRECIPITATION
MAKING IT INTO NORTHEAST NEB WHILE THE 00Z/12 EC/12Z 4KM WRF AND
THE LATEST HRRR ARE A BIT STRONGER WITH THE WAVE IN GENERATING
LIGHT SNOW FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. ALTHOUGH
THERE ARE QUITE A FEW RETURNS SHOWING UP AT 21Z...SFC REPORTS ARE
STILL SPARSE IN REPORTING THE SNOW. LOOKING AT THE FORCING...
SATURATION...AND COLDEST TEMPS HAVE INCLUDED SOME SLIGHT CHC TO
CHC POPS OVER ESPECIALLY THE NORTHEASTERN THIRD OF THE CWA. AT
THIS TIME ONLY ADDED SOME VERY LIGHT AMOUNTS TO THE NORTHEAST.
ALTHOUGH SURFACE DEWPOINTS ARE VERY LOW (BELOW ZERO WRN IA AND THE
ALONG THE MISSOURI RIVER)...LOOK FOR THEM TO INCREASE OVERNIGHT
INTO THE TEENS AND 20S. WITH A SURFACE LOW TRACKING ACROSS THE
AREA OVERNIGHT...TEMPERATURES WILL BE TRICKY...FALLING OFF QUICKLY
TONIGHT IN WRN IOWA...BUT BEING HELD UP ACRS THE WRN CWA.
MID LEVEL RIDGING WILL BUILD IN FOR THE WEEKEND. WARMER
TEMPERATURES ARE FORECAST FOR WEEKEND WITH 50S FOR SUNDAY. THE
NEXT COLD FRONT MOVES THROUGH OVERNIGHT SUNDAY AND LOW CLOUDS AND
SOME DRIZZLE COULD DEVELOP IN SOUTHWEST IOWA. COLDER AIR WILL
RETURN FOR MONDAY WITH LIGHT SNOW DEVELOPING OVER SOUTH DAKOTA AND
WESTERN AND CENTRAL NEBRASKA. THIS LIGHT SNOW COULD START TO MAKE
IT INTO PARTS OF THE WESTERN FORECAST AREA BY DAY/S END.
ZAPOTOCNY
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
MODELS CERTAINLY DIVERGE REGARDING THE AMOUNT AND INTENSITY OF COLD
AIR PLUNGING INTO THE PLAINS BY MID TO LATE WEEK. THE OPERATIONAL
GFS HAS REMAINED THE COLDEST OF THE MEDIUM RANGE MODELS...WITH ECMWF
THE WARMEST. GFS ENSEMBLE MEMBERS OFFER NO HELP AS THE SPREAD IS
WIDE HERE TOO. IN FACT...THE 00Z ENSEMBLE TEMPERATURES FOR THURSDAY
HIGHS RANGED FROM 21 TO 49 AT OMAHA.
LEADING UP TO THIS TIME PERIOD...A SIMILAR EVOLUTION OF THE UPPER
FLOW PATTERN IS NOTED BY GFS/ECMWF. BOTH SHOW A BROAD TROUGH OVER
THE CENTER OF THE COUNTRY WITH A SHORTWAVE MOVING THROUGH NEBRASKA
AND IOWA MONDAY NIGHT AND TUESDAY. AND BOTH MODELS BREAK OUT LIGHT
SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS NORTHERN NEBRASKA INTO
NORTHERN IOWA. OUR CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST
MONDAY NIGHT...SO LEFT THAT UNCHANGED. HOWEVER...SLIGHTLY SLOWER
ECMWF KEEPS SNOW IN FOR TUESDAY. IF THIS OCCURS IT SHOULD ONLY
AFFECT OUR EAST AND SHOULD BE ENDING QUICKLY IN THE MORNING.
THEN UPPER PATTERN BEGINS TO FLATTEN OUT SOME...WITH NORTHWEST FLOW
THE CONSENSUS FOR WEDNESDAY. HIGHS IN THE 20S TUESDAY IN COOL
ADVECTION REGIME WILL WARM INTO THE 30S WEDNESDAY.
THURSDAY IS THE BIG QUESTION MARK AS THE GFS CONTINUES TO SHOW
STRONG BAROCLINIC ZONE DROPPING THROUGH THE CWA WHILE ECMWF KEEPS
BRUNT OF COLD AIR TO OUR NORTHEAST. DURING NORMAL WINTERS WOULD
EXPECT THE GFS AND COLD AIR TO WIN OUT...BUT THIS HAS BEEN ANYTHING
BUT A NORMAL WINTER. WE HAVE SEEN THESE SCENARIOS ADVERTISED AT DAYS
6 AND 7 BEFORE...AND TRENDING TOWARD WARMER SOLUTIONS HAS BEEN BEST.
ESPECIALLY WITH LIMITED SNOW COVER TO OUR NORTH. BOTH SIDES OF THE
ARGUMENT HAVE MERIT...SO TO STAY CONSISTENT WITH CURRENT
FORECAST...SURROUNDING OFFICES AND WIDELY DIVERGENT MODELS...WILL
HAVE TO KEEP TEMPERATURES CLOSE TO WHAT WE CURRENTLY HAVE GOING WITH
HIGHS IN THE 20S AND LOWER 30S. WHATEVER THE CASE...EXPECT A LITTLE
WARMER CONDITIONS ON FRIDAY AS RETURN FLOW SETS UP. MAY ALSO SEE
SOME LIGHT SNOW WITH THIS SCENARIO.
DERGAN
AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL SITES THROUGH THE
TAF PERIOD. A FRONTAL BOUNDARY WILL APPROACH THE CWA THIS
AFTERNOON...BRINGING WINDS AROUND TO THE SOUTHEAST AHEAD OF THE
FRONT. OVERNIGHT...WINDS BEHIND THE FRONT ARE EXPECTED TO
INCREASE AND SWITCH TO THE NORTHWEST.
ROUKE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
230 AM CST SAT JAN 14 2012
.DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES
TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR
DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL
USE BLEND.
BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND
WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON
CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND
THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER
OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS
BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE
LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES
FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST
AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE
BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION
LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY.
FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN
THE 20S.
TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY
MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND
WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN
CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE.
NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN
BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF
FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG
WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY
OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS
COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED
32 DEGREES.
STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT
INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE
BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS
FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY
TO RECOVER AT ALL MONDAY AND MAY EVEN DROP.
.LONG TERM (TUE-FRI)...
MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC
AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO
NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT
SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK
FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA.
&&
.AVIATION...
CIGS WILL CONTINUE TO FLOP BETWEEN VFR AND MVFR IN LIGHT SNOW BAND
AREA ALONG SOUTHERN VALLEY INTO WESTERN MN THIS MORNING. EXPECT MORE
VFR CONDITIONS ALONG AND WEST OF VALLEY. VSBYS IN -SN THIS
MORNING WILL BE PRIMARILY VFR WITH SOME BRIEF MVFR IN HEAVIER SNOW
SHOWERS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER/JIMMY K
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
406 AM EST SAT JAN 14 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH
PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES
AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT
LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE
WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH
ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY
BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVERGENCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND
THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE
NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A
MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE
LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE
REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE
EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY
STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM.
A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG
SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME
A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE
EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY
HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENDRITES IN
THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP
SNOW AMTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH.
BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK
SNOW WARN.
WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT
NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE
NORMAL FOR THE SECOND WEEK OF JANUARY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO
THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT
DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H
FLOW DOES NOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT
MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN
CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO
STAY JUST SUB-NORMAL THRU THE SHORT TERM PD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE
SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP
WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW
SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY
BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN
THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT
AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON
FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY
INCH OR TWO.
THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY
WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE.
THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE
NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY
CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF
INTERSTATE 80.
THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND
EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE
EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE
STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND
WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU
BY LATER SUNDAY NIGHT.
MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE
EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW
DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME
RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB
TO PLUS 3-6C ACROSS MUCH OF THE CWA.
THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY
TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH
AHEAD OF AN APPROACHING CFRONT.
COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY
WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW
SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY
NIGHT.
NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL
OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES
OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
09Z UPDATE...NO CHANGES TO 06Z SCHEDULED ISSUANCE.
COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE
GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW
SHOWERS. POOR FLYING CONDS WILL PERSIST ACROSS THE W MTNS...WHERE
VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST. DOWNSLOPING FLOW E
OF THE MTNS WILL RESULT IN ONLY SCT FLURRIES...WITH MVFR CIGS AT
UNV/AOO AND LOW END VFR AT LNS/MDT/IPT. W/SW WIND GUSTS BTWN
15-25KTS WILL BE COMMON THRU MOST OF THE DAY.
OUTLOOK...
SUN...MVFR CIGS WEST...BCMG VFR.
MON...VFR.
MON NGT...MVFR WEST/VFR EAST. -RA LKLY WEST.
TUES...MVFR AND IFR LKLY IN RA/SN.
WED...WINDY. MVFR AND IFR -SHSN W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/STEINBUGL
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
134 AM EST SAT JAN 14 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH
PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES
AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT
LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE
WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH
ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY
BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
CONVERGANCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND
THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE
NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A
MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE
LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE
REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE
EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY
STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM.
A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG
SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME
A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE
EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY
HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENRITES IN
THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP
SNOW AMOUTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH.
BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK
SNOW WARN.
WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT
NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE
NORMAL FOR THE SECOND WEEK OF JANUARY.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO
THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT
DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H
FLOW DOESNOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT
MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN
CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO
STAY JUST SUB-NORMAL THRU THE SHORT TERM PD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE
SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP
WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW
SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY
BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN
THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT
AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON
FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY
INCH OR TWO.
THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY
WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE.
THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE
NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY
CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF
INTERSTATE 80.
THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND
EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE
EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE
STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND
WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU
BY LATER SUNDAY NIGHT.
MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE
EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW
DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME
RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB
TO PLUS 3-6C ACROSS MUCH OF THE CWA.
THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY
TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH
AHEAD OF AN APPROACHING CFRONT.
COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY
WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW
SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY
NIGHT.
NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL
OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES
OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE
GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW
SHOWERS. POOR FLYING CONDS WILL PERSIST ACROSS THE W MTNS...WHERE
VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST. DOWNSLOPING FLOW E
OF THE MTNS WILL RESULT IN ONLY SCT FLURRIES...WITH MVFR CIGS AT
UNV/AOO AND LOW END VFR AT LNS/MDT/IPT. W/SW WIND GUSTS BTWN
15-25KTS WILL BE COMMON THRU MOST OF THE DAY.
OUTLOOK...
SUN...MVFR CIGS WEST...BCMG VFR.
MON...VFR.
MON NGT...MVFR WEST/VFR EAST. -RA LKLY WEST.
TUES...MVFR AND IFR LKLY IN RA/SN.
WED...WINDY. MVFR AND IFR -SHSN W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/STEINBUGL
AVIATION...FITZGERALD/STEINBUGL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1030 PM CST FRI JAN 13 2012
.DISCUSSION.../ISSUED AT 750 PM CST/
AREA OF LIGTH SNOW IN THE JAMES VALLEY CONTINUES TO FILL IN
ASSOCIATED WITH SOME 800-900MB FRONTOGENESIS. LATEST RUC SHOWS THAT
THIS TREND SHOULD CONTINUE THROUGH 06Z...SPREADING INTO THE I-29
CORRIDOR...THEN PULLING EASTWARD INTO MN AND IA AFTER 06Z THEN EAST
OF THE FORECAST AREA BY 12Z. AMOUNTS STILL LOOK TO BE RATHER LIGHT
WITH ONE HALF INCH OR LESS EXPECTED. OTHERWISE...STEADY TO SLOWLY
RISING TEMPERATURES OVERNIGHT AS FORECAST EARLIER STILL LOOK ON
TRACK.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR THROUGH MOST OF THE PERIOD...WITH OCCASIONAL MVFR CEILINGS AND
VISBILITIES THROUGH 12Z AS LIGHT SNOW MOVES SOOUTHEAST ACROSS THE
REGION. LOWER CLOUDS SHOULD DISSIPATE AFTER 12Z AND NORTHWEST WINDS
OF 15 TO 20 MPH WILL DEVELOP ON SATURDAY AND THEN BECOME LIGHT
TOWARDS SUNSET.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 300 PM CST/
LATEST WATER VAPOR LOOP SHOWING A FAIRLY STRONG WAVE DIGGING INTO
EASTERN MONTANA LATE THIS AFTERNOON WHICH WILL BRING THE SHOT OF
LIGHT SNOW TO THE AREA TONIGHT. STRONGER BAROCLINICITY CONFINED TO
THE LOWEST LEVELS OF THE ATMOSPHERE AND DO NOT EXPECT THIS TO PLAY
A BIG ROLE IN PRECIPITATION PRODUCTION. HIGHER UP...AROUND
700MB...NOT MUCH OF A THERMAL GRADIENT SO AT LEAST WITH THIS EVENT
PLANNING ON FOLLOWING THE UPPER LEVEL PV ADVECTION AS WELL AS THE
750-650MB THETA E RIDGING. THIS WILL BRING A CHANCE FOR SNOW INTO
CENTRAL SOUTH DAKOTA BETWEEN 0Z AND 3Z WITH AN INCREASING CHANCE
ACROSS CENTRAL PARTS OF THE CWA FROM ABOUT 3Z THROUGH 9Z...THEN
LIKELY PEELING INTO NORTHWEST IOWA FROM ABOUT 6Z THROUGH 12Z. NOT
PLANNING ON TOO MUCH ACCUMULATION WITH MOST LOCATIONS AN INCH OR
LESS. TEMPERATURES WILL REMAIN STEADY TO RISING THROUGH THE NIGHT AS
WELL WITH MORNING TEMPERATURES ABOUT 20 DEGREES WARMER THAN THIS
MORNING.
BY SATURDAY THE BULK OF THE ACTIVITY SHOULD BE EAST OF THE AREA WITH
A MARGINALLY BREEZY NORTHWEST DEVELOPING. HIGHS MOSTLY UNCHANGED
FROM EARLIER...RANGING FROM NEAR 30 IN THE NORTHERN CWA TO THE UPPER
30S IN THE SOUTH.
A SURFACE RIDGE SLIDES QUICKLY TO THE EAST ON SATURDAY NIGHT...WITH
A SOUTHERLY FLOW RETURNING TO THE AREA DURING THE NIGHT TIME HOURS
OUT AHEAD OF A TROUGH PUSHING OUT OF THE NORTHERN ROCKIES. WITH
THIS...TEMPERATURES WILL BE TRICKY ON SATURDAY NIGHT...INITIALLY
DROPPING PRETTY QUICKLY...THEN STEADYING OUT AND RISING IN SOME
AREAS OVERNIGHT WITH LOW LEVEL WARM AIR ADVECTION AND AN INCREASING
GRADIENT. LOWS EARLY LOOKING TO BE IN THE UPPER TEENS TO LOWER 20S.
SUNDAY WILL BE THE WARMEST DAY OF THE NEXT SEVERAL OUT AHEAD OF THE
APPROACHING SURFACE TROUGH. THOUGH WITH SOME MODEL
DIFFERENCES...MIXING LOOKS TO BE AROUND 925 MB...WHERE TEMPERATURES
WILL BE APPROXIMATELY IN THE RANGE OF 1 TO 7 DEGREES C FROM NORTH TO
SOUTH...AND HIGHS WILL BE FROM LOWER 40S NORTH OF THE INTERSTATE 90
CORRIDOR TO AROUND 50 FROM LAKE ANDES TO SIOUX CITY TO STORM LAKE.
COLD FRONT DROPS SOUTHWARD ACROSS THE REGION ON SUNDAY NIGHT
BRINGING AND END TO THE WARMTH...WITH LOWS IN THE UPPER TEENS TO MID
20S.
CONFIDENCE IN MONDAY/MONDAY NIGHT DETAILS RATHER LOW...WITH MODELS
SPLIT IN THE DETAILS REGARDING TIMING AND PLACEMENT OF MIDLEVEL
THERMAL GRADIENT AND SHORTWAVE TRACKING ACROSS THE CENTRAL PLAINS
DURING THAT TIME FRAME. DOES LOOK LIKE THERE WILL BE A PERIOD OF
LIGHT SNOW ACROSS THE AREA SOMETIME LATER ON MONDAY AND MONDAY
NIGHT...WITH MAYBE AN INCH TO INCH AND HALF OR SO OF ACCUMULATION
POSSIBLE AT THIS POINT. WILL BE SOMETHING TO WATCH HOWEVER. WITH
COLD AIR ADVECTION MONDAY WILL BE COLDER WITH HIGHS MAINLY IN THE
20S.
IN THE EXTENDED...TUESDAY THROUGH FRIDAY...APPEARS TO BE GENERALLY
COLD THROUGH THE PERIOD AS A SERIES OF REINFORCING SHORTWAVES TRACK
ACROSS THE NORTHERN PLAINS/UPPER MIDWEST IN A NORTHWESTERLY UPPER
LEVEL FLOW. CANNOT RULE OUT A COUPLE PERIODS OF LIGHT SNOW DURING
THAT TIME FRAME...THOUGH HARD TO PIN DOWN WITH USUAL MODEL
DIFFERENCES. TUESDAY AND THURSDAY LOOKING TO BE THE COLDEST
DAYS...IN THE TEENS...WARMING TO 20S TO LOWER 30S BY FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
630 AM EST SAT JAN 14 2012
.SYNOPSIS...
A COLD FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA TODAY AND
TONIGHT. COLD HIGH PRESSURE FROM THE WEST IS EXPECTED TO
INFLUENCE OUR WEATHER FOR SUNDAY AND SUNDAY NIGHT BEFORE PASSING
OUT TO SEA ON MONDAY. A WARM FRONT FROM THE WEST AND SOUTHWEST IS
ANTICIPATED TO WORK ITS WAY THROUGH OUR REGION ON TUESDAY,
FOLLOWED BY A COLD FRONT ON TUESDAY NIGHT. AN AREA OF HIGH
PRESSURE IS EXPECTED FOR WEDNESDAY AND THURSDAY. A WEAK FRONTAL
BOUNDARY FROM THE NORTHWEST MAY ARRIVE ON THURSDAY NIGHT OR
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A 10Z SURFACE ANALYSIS PLACED A COLD FRONT FROM NEW ENGLAND TO
THE UPPER OHIO VALLEY. HIGH PRESSURE WAS OVER THE UPPER GREAT
LAKES WITH ANOTHER HIGH ALONG THE GULF COAST. LOW PRESSURE WAS
JUST NORTH OF THE DAKOTAS ALONG A FRONTAL BOUNDARY TO ANOTHER LOW
IN THE CENTRAL PLAINS. AN UPPER AIR ANALYSIS PLACED A DEEP TROUGH
ACROSS THE EASTERN STATES WITH SEVERAL SHORT WAVES EMBEDDED WITHIN
THE FLOW. AN AREA OF FOCUSED WAA AT 850 MB WAS ACROSS THE CENTRAL
PLAINS. A CYCLONICALLY CURVED 300 MB JET WAS FROM THE NORTHERN
ROCKIES TO THE LOWER MISSISSIPPI VALLEY THEN UP THE EAST COAST.
A STRONG SURFACE LOW WILL REMAIN IN THE CANADIAN MARITIMES TODAY.
THIS WILL RESULT IN A CONTINUED CYCLONIC FLOW OF COLD AIR ACROSS
THE ENTIRE REGION. A SECONDARY COLD FRONT WILL WRAP AROUND THIS
SURFACE LOW AND WILL BE SETTLING SOUTHWARD ACROSS OUR AREA. THE
OVERALL LOW-LEVEL MOISTURE IS LACKING WITH THIS BOUNDARY, HOWEVER
THERE IS A RIBBON OF DECENT LIFT, CONVERGENCE AND STEEPENING LOW-
LEVEL LAPSE RATES. GIVEN THE WESTERLY FLOW OF COLD AIR, SOME ADDED
MOISTURE FROM LAKE ERIE MAY COME INTO PLAY THROUGH THE DAY. SOME
OF THE HIGHER RESOLUTION MODELS LIKE THE NAM/WRF, THE SPC 4KM WRF
AND THE HRRR HINT AT A CONNECTION BETWEEN A LAKE ERIE PLUME AND
THE COLD FRONT. ALOFT, AN AREA OF CHANNELIZED VORTICITY IS
FORECAST TO PIVOT NEARLY CLOSE TO THE SURFACE FRONT. THIS MAY HELP
TO PULL THE LAKE SNOW PLUME EASTWARD IN THE FORM OF A NARROW BAND.
THE FORECAST SOUNDINGS ACROSS THE NORTHWESTERN ZONES SHOW THE
INVERSION STAYING HIGH ENOUGH TO ALLOW THE SYNOPTIC LIFT TO OCCUR
WITHIN THE FAVORABLE SNOW GROWTH REGION. IF A BAND OF SNOW DOES
DEVELOP, A QUICK BURST MAY RESULT. THE ABOVE MENTIONED MODELS, AND
TO SOME EXTENT THE GFS, BRING THIS ALL THE WAY TO THE POCONOS TO
EVEN PORTIONS OF NORTHERN NEW JERSEY. OUR CONFIDENCE IS LOW
REGARDING HOW THIS MAY PLAY OUT, BUT THERE IS THE POTENTIAL FOR A
NARROW BAND OF HEAVIER SNOW SHOWERS MOVING THROUGH PARTS OF THE
NORTHWESTERN ZONES. THIS THEN SETTLES SOUTHWARD WITH THE FRONT BUT
WEAKENS AS THE MAIN SUPPORT TRACKS FARTHER NORTH. SOME WEAK SHORT
WAVE ENERGY IS HELPING TO PRODUCE SOME FLURRIES OR A FEW SNOW
SHOWERS ACROSS MAINLY THE POCONOS EARLY THIS MORNING. SOME SLIGHT
CHC POPS WERE USED EARLY THIS MORNING, THEN WE LEANED TOWARD THE
NAM/WRF FOR POPS WHICH PLACES POPS IN THE SLIGHT CHC TO CHC RANGE
MAINLY ACROSS NORTHEASTERN PENNSYLVANIA. WE KEPT ABOUT ONE-HALF
INCH OF SNOW ACCUMULATION ACROSS THE POCONOS.
ELSEWHERE, LITTLE TO NOTHING IS EXPECTED WITH THE FRONTAL PASSAGE
OTHER THAN A BAND OF STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS.
THE TAIL END OF A WEAK SHORT WAVE IS HELPING TO GENERATE A SWATH
OF MAINLY MID LEVEL CLOUDS ACROSS THE SOUTHEASTERN ZONES EARLY
THIS MORNING. SOME RETURNS HAVE BEEN SHOWING UP ON RADAR ACROSS
NORTHEASTERN MARYLAND TO SOUTHWESTERN NEW JERSEY. PERHAPS A FEW
FLURRIES REACH THE GROUND, BUT OVERALL THIS LOOKS TO BE MID LEVEL
MOISTURE ONLY. BACK TO THE STRATOCUMULUS, THIS WILL BE AROUND
TODAY ESPECIALLY ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW
JERSEY AS THE WESTERLY FLOW MAINTAINS ENOUGH MOISTURE UNDER AN
INVERSION. THE FORECAST SOUNDINGS INDICATE WE SHOULD GET RATHER
CLOSE TO THE CONVECTIVE TEMPERATURES TODAY DESPITE THE LOWER
LEVELS BEING RATHER DRY. THIS SHOULD RESULT IN AT LEAST SOME
STRATOCUMULUS BELOW SOME HIGHER CLOUDS ACROSS THE REST OF THE CWA,
WHICH MAY RESULT IN VARYING CLOUD COVER THROUGH THE DAY. BASED ON
SATELLITE TRENDS AS OF 11Z, WE INCREASED THE SKY COVER FARTHER
EAST FOR AWHILE THIS MORNING.
A WESTERLY WIND WILL CONTINUE TO BE ON THE BRISK SIDE AS VERTICAL
MIXING IS MAINTAINED. THE WINDS HOWEVER ARE EXPECTED TO BE LESS
THAN WHAT WAS OBSERVED YESTERDAY, AND SETTLE DOWN LATER IN THE
AFTERNOON. AS FOR TEMPERATURES, WE MAINLY TOOK AN EVENLY WEIGHTED
BLEND OF THE MOS GUIDANCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE AFOREMENTIONED SECONDARY COLD FRONT WILL CONTINUE TO SETTLE
SOUTHWARD BEFORE POTENTIALLY DISSIPATING. THERE COULD BE SOME
LINGERING FLURRIES OR A SNOW SHOWER WITH IT ESPECIALLY IN THE
WESTERN ZONES. HOWEVER, ANYTHING WITH IT SHOULD BE WANING WITH A
SOUTHERN EXTENT AS THE OVERALL LIFT AND MOISTURE DWINDLES AS WELL
AS A GRADUAL INCREASE IN THE SUBSIDENCE AND A LESS FAVORABLE FETCH
FROM THE LAKES. THEREFORE, KEPT THE SKY COVER A BIT HIGHER FOR A
TIME WITHIN A WEST TO EAST BAND WITH THE SOUTHBOUND FRONT. THERE
MAY BE ENOUGH MID LEVEL MOISTURE AROUND TO KEEP SOME CLOUDS
AROUND, BUT OVERALL AN EVEN DRIER PUSH OF AIR FROM THE NORTH
SHOULD RESULT IN SOME SCATTERING IN THE CLOUDS ESPECIALLY SOUTH
AND EAST OF THE PHILADELPHIA METRO AREA.
AS STRENGTHENING HIGH PRESSURE BUILDS ACROSS SOUTHEASTERN CANADA
AND THE EASTERN GREAT LAKES LATE TONIGHT, THE NORTHERLY FLOW WILL
DRIVE A COLDER AIR MASS OVER OUR AREA. THE 850 MB TEMPERATURES ARE
FORECAST TO DROP TO NEAR -15C OVERNIGHT. THERE IS SOMEWHAT OF A
PRESSURE GRADIENT REMAINING DURING THE NIGHT, HOWEVER THE OVERALL
MIXING SHOULD TEND TO BECOME MUCH MORE REDUCED AS THE NIGHT WEARS
ON. THIS WILL RESULT IN A RATHER COLD NIGHT ACROSS THE ENTIRE
AREA.
AS FOR TEMPERATURES, WE GENERALLY WENT WITH A BLEND OF THE
GFS/NAM MOS WITH SOME TWEAKS MAINLY FOR THE TYPICALLY COLDER
LOCALES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MOSTLY CLEAR AND COLD WEATHER IS ANTICIPATED FOR SUNDAY AND
SUNDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS OUR REGION. MAXIMUM
TEMPERATURES SHOULD RANGE FROM THE UPPER TEENS IN THE POCONOS TO
THE MIDDLE 30S IN SOUTHERN DELAWARE. FOR SUNDAY NIGHT, READINGS
ARE FORECAST TO DROP INTO THE TEENS THROUGHOUT MOST OF OUR REGION
WITH A LIGHT WIND AND GOOD RADIATIVE CONDITIONS.
THE MID LEVEL RIDGE AXIS IS FORECAST TO PASS OVERHEAD ON MONDAY
MORNING WITH STRONG WARM ADVECTION DEVELOPING ALOFT. FROM MONDAY
INTO MONDAY EVENING WE SHOULD SEE AN INCREASE IN HIGH, THEN MID
LEVEL CLOUDS.
ON MONDAY NIGHT, A DEVELOPING JET AROUND 850 HPA WILL BE LOCATED
OVER THE OHIO RIVER VALLEY, AHEAD OF OUR NEXT WEATHER SYSTEM
APPROACHING FROM THE WEST. THE JET SHOULD DROP SLOWLY
SOUTHEASTWARD, POINTING SQUARELY AT OUR FORECAST AREA. IT WILL ACT
TO DIRECT MOISTURE INTO OUR REGION RATHER QUICKLY. MONDAY NIGHT
SHOULD START DRY. HOWEVER, PRECIPITATION IS EXPECTED TO OVERSPREAD
OUR REGION. WITH COLD DRY AIR IN PLACE AT THE LOW LEVELS, WE MAY
VERY WELL ENCOUNTER PRECIPITATION TYPE ISSUES, MAINLY IN EASTERN
PENNSYLVANIA AND NORTHERN AND CENTRAL NEW JERSEY. BASED ON THEN
EXPECTED TEMPERATURE PROFILES AND THE ANTICIPATION THAT STRONG
WARM ADVECTION ALOFT WILL CONTINUE, IT APPEARS AS THOUGH WE MAY
SEE A MIX OF MAINLY SLEET AND FREEZING RAIN IN OUR NORTHWESTERN
COUNTIES. A LITTLE SNOW IS ALSO POSSIBLE. HOWEVER, THAT WILL
DEPEND UPON A SOMEWHAT WEAKER INITIAL PUSH OF WARM AIR ALOFT THAN
MOST OF THE GUIDANCE IS CURRENTLY SUGGESTING. ON THE COASTAL
PLAIN, IT LOOKS AS THOUGH TEMPERATURES AT THE SURFACE AND ALOFT
WILL SUPPORT ALL RAIN ON MONDAY NIGHT.
AS THE WARM ADVECTION CONTINUES ON TUESDAY. THE WINTRY
PRECIPITATION SHOULD CHANGE TO ALL RAIN. THE RAIN MAY BECOME
SHOWERY DURING THE AFTERNOON. WE ARE NOT PARTICULARLY CONFIDENT IN
THE TEMPERATURE FORECAST FOR TUESDAY. THE LOW LEVEL COLD AIR MAY
BE A LITTLE MORE STUBBORN UP NORTH THAN OUR FORECAST INDICATES.
ALSO, IN OUR FAR SOUTHERN COUNTIES, SIGNIFICANT BREAKS IN THE
CLOUD COVER COULD RESULT IN TEMPERATURES HIGHER THAN THOSE WE ARE
FORECASTING.
A COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE ON TUESDAY NIGHT
WITH HIGH PRESSURE AND DRY WEATHER FOLLOWING FOR WEDNESDAY AND
THURSDAY. THE SOURCE REGION FOR THE AIR MASS WILL BE MORE FROM THE
WEST THAN THE NORTHWEST, SO TEMPERATURES WILL LIKELY BE ABOUT
NORMAL FOR THIS TIME OF THE YEAR.
A WEAK FRONTAL BOUNDARY MAY DROP INTO OUR REGION FROM THE
NORTHWEST LATE IN THE WEEK. FOR NOW, WE HAVE SIMPLY INDICATE A
SLIGHT CHANCE OF SNOW SHOWERS WITH THE FEATURE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A STRONG LOW PRESSURE SYSTEM IN THE CANADIAN MARITIMES THROUGH
TONIGHT WILL MAINTAIN A WEST TO NORTHWEST FLOW ACROSS OUR AREA. A
SECONDARY FRONT WILL SETTLE SOUTHWARD ACROSS OUR AREA FROM LATER
THIS MORNING THROUGH THE EVENING. THERE IS NOT MUCH FORCING AND
MOISTURE WITH THIS BOUNDARY, HOWEVER THERE ARE SOME HINTS IN THE
MODEL GUIDANCE THAT MOISTURE FROM THE EASTERN GREAT LAKES GETS
PULLED EASTWARD WITH THIS FRONT. THIS MAY RESULT IN ENOUGH LOW-
LEVEL CONVERGENCE TO ALLOW FOR A NARROW BAND OF FLURRIES OR
HEAVIER SNOW SHOWERS ACROSS THE NORTHERN PORTION OF PENNSYLVANIA
INTO NORTHWESTERN NEW JERSEY. AS A RESULT, A FEW SNOW SHOWERS MAY
GET TO AT LEAST KABE. GIVEN THE LOWER CONFIDENCE WITH THE TIMING
AND EXTENT OF ANY SNOW SHOWERS, WE DID NOT CARRY A MENTION IN THE
TAFS AT THIS TIME.
THE COLD WESTERLY FLOW COMBINED WITH SOME WEAK ENERGY MOVING
THROUGH AND ENOUGH MOISTURE TRAPPED UNDER AN INVERSION, IS HELPING
TO PULL STRATOCUMULUS DOWN ACROSS MOST OF THE AREA ALONG WITH MID
LEVEL CLOUDINESS. THIS IS EXPECTED TO CONTINUE WITH AT LEAST
BROKEN CEILINGS AROUND 4,000 FEET, ESPECIALLY FROM THE KPHL METRO
AREA ON NORTH AND WESTWARD. THE WINDS HAVE BEEN DECOUPLING SOME
WITH GUSTS DROPPING OFF AT SOME OF THE TERMINALS EARLY THIS
MORNING. ALL OF OUR TERMINALS ARE EXPECTED TO HAVE SOME GUSTS IN
THE 20-25 KNOT RANGE FOR AWHILE TODAY BEFORE SETTLING DOWN LATER
IN THE AFTERNOON AND TONIGHT. THE AFOREMENTIONED BOUNDARY SHOULD
MAINTAIN SOME STRATOCUMULUS AND EVEN SOME MID LEVEL CLOUDS WITH IT
AS IT DROPS SOUTHWARD THROUGH THE EVENING. THIS BOUNDARY WILL ALSO
TURN THE SURFACE WINDS MORE TO THE NORTHWEST THROUGH TONIGHT.
OUTLOOK...
DRY WEATHER AND VFR CONDITIONS ARE FORECAST FOR SUNDAY AND
MONDAY. PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION FROM
THE WEST ON MONDAY NIGHT AND IT SHOULD CONTINUE INTO TUESDAY. THE
PRECIPITATION MAY BEGIN AS A WINTRY MIX ON MONDAY NIGHT AT KRDG,
KABE AND PERHAPS KTTN. ALL RAIN IS ANTICIPATED FOR KPHL, KPNE,
KILG, KMIV AND KACY.
A COLD FRONT IS EXPECTED TO PASS THROUGH OUR REGION ON TUESDAY
NIGHT, BRINGING AND END TO THE RAIN. HIGH PRESSURE AND DRY WEATHER
SHOULD FOLLOW FOR WEDNESDAY.
&&
.MARINE...
AN INTENSE SURFACE LOW OVER THE CANADIAN MARITIMES WILL CONTINUE
TO CIRCULATE A COLD AIR MASS OVER OUR REGION UNDER A WESTERLY FLOW.
A SECONDARY COLD FRONT WILL SWING AROUND THIS LOW AND SETTLE
SOUTHWARD ACROSS THE AREA TODAY INTO TONIGHT. SOME COLDER AIR WILL
ADVECT INTO THE AREA BEHIND THIS FRONT THROUGH TONIGHT. THE
PRESSURE GRADIENT REMAINS TIGHTENED TODAY INTO TONIGHT, HOWEVER
THE OVERALL WIND FIELD IS FORECAST TO LESSEN WITH TIME. THIS HAS
ALREADY BEEN NOTED AS THE WINDS HAVE BEEN GRADUALLY COMING DOWN
EARLY THIS MORNING. WHILE THERE COULD BE SOME UPTICK FOR A TIME
THIS MORNING DUE TO A LITTLE BETTER MIXING, IT MIGHT END UP BEING
A MORE MARGINAL SETUP FOR A SMALL CRAFT ADVISORY /ESPECIALLY
ACROSS THE SOUTHERN ZONES/. BASED ON THE SOUNDINGS AND TO ALLOW
FOR SOME WIGGLE ROOM, THE ADVISORY WILL RUN UNTIL 18Z FOR ALL
AREAS. THIS CAN ALWAYS BE CANCELLED EARLY. OTHERWISE, A DOWNWARD
TREND IN THE SEAS AND WINDS UNDER ADVISORY CRITERIA ARE EXPECTED
TONIGHT AS HIGH PRESSURE EDGES CLOSER.
WITH THE NORTHWEST FLOW PERSISTING INTO SUNDAY, WIND GUSTS TO
AROUND 25 KNOTS ARE POSSIBLE AT THAT TIME. HIGH PRESSURE SHOULD
BUILD ACROSS THE COASTAL WATERS OF NEW JERSEY AND DELAWARE ON
SUNDAY NIGHT AND EARLY MONDAY, BRINGING RELATIVELY TRANQUIL
CONDITIONS.
WIND SPEEDS ARE FORECAST TO BE ON THE INCREASE AGAIN LATE ON
MONDAY AS OUR NEXT WEATHER SYSTEM BEGINS TO APPROACH FROM THE
WEST. A BRISK SOUTHERLY FLOW IS ANTICIPATED FOR MONDAY NIGHT AND
TUESDAY WITH WIND GUSTS IN EXCESS OF 25 KNOTS, ALONG WITH WAVE
HEIGHTS ON OUR OCEAN WATERS BUILDING TO 5 TO 8 FEET.
A COLD FRONT IS EXPECTED TO PASS ACROSS THE REGION ON TUESDAY
NIGHT. THE WIND DIRECTION WILL LIKELY SHIFT TO THE WEST. HOWEVER,
GUSTS NEAR 25 KNOTS WILL REMAIN POSSIBLE INTO WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-
431-450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
AREA FORECAST DISCUSSION...updated for aviation section
NWS TALLAHASSEE FL
535 AM EST Sat Jan 14 2012
.SYNOPSIS...
08Z water vapor and H4 RUC analysis shows an upper level pattern
consisting of longwave troughing over much of the inter-mountain
west, followed downstream by longwave troughing over much of the
CONUS east of the continental divide. A series of shortwaves
beginning to arrive along the British Columbia coastline will slowly
break down the western U.S. ridge during the upcoming weekend which
will lead to eventual height rises and an overall warmup for the
eastern states by the early portion of next week.
For now however, watching a shortwave impulse rounding the base of
the main eastern trough over the SE states early this morning. The
trough axis is just now exiting east of our area, seen with an
expanding area of subsidence/drying overhead on WV imagery. A final
piece of energy is sliding down the backside of the trough through
the mid-section of the country. This energy will slide to our north
tonight allowing height rises in its wake for Sunday.
At the surface, 1028mb high pressure centered along the TX/LA coasts
continues to build east into our forecast area. As the ridge expands
eastward, the local gradient has been slowly weakening allowing for
an increasingly efficient radiational cooling setup. Still
anticipate a widespread light freeze by sunrise away from the
immediate coast. A few isolated and normally colder locations may
still briefly reach hard freeze criteria in the hour or two
surrounding sunrise.
&&
.SHORT TERM (TODAY THROUGH MONDAY)...
Today,
Subsidence behind the departing shortwave this morning will help
promote mostly sunny skies through the day. However, a slight
re-enforcing shot of CAA...especially above the surface will keep
temperatures a bit below normal. At the surface, high pressure will
continue to expand eastward with a high center forming over the
coastal waters by the later afternoon/evening hours. To our north, a
weak surface reflection/low associated with the final shortwave
impulse will translate quickly from MO this afternoon, to the TN
valley this evening. Associated with this feature will be a weak
cold front that will cross northern AL/GA and into the Carolinas.
Although this cold front will not directly pass through our area, it
will have an influence of somewhat tightening the gradient over our
northern zones later today/this evening. The tighter gradient may
have an impact on temperatures tonight. Before that, afternoon temps
today are expected to top out in the mid/upper 50s.
Tonight,
As mentioned above, some uncertainly with regards to temperatures
relating to how rapidly the gradient will collapse again over our
northern/NE zones in the wake of a passing cold front/trough. The
impact looks to be least along and south of the I-10 corridor where
proximity to the eastward extension of the surface ridge should set
up good radiational cooling conditions early. The temperatures drop
may be slower this evening further to the north, however the
GFS/ECMWF both show a quick exit of the trough and the potential for
late night de-coupling. Therefore, will not deviate far from a
MET/MAV blend for overnight lows. Generally looking for lows in the
low/mid 30s inland and mid/upper 30s at the coast. Does appear that
any location which do reach or drop just below freezing will not do
so until right around sunrise, with a fairly short duration of near
freezing temps. If the tighter gradient holds longer than numerical
guidance currently suggest, then low temps would not be quite as
cold for areas north of KTLH and KVLD.
Sunday/Sunday night,
Very pleasant day upcoming for the second half of the weekend.
Rising heights over-top a strong surface ridge will provide the
region with dry and seasonable conditions. Winds will be on the
light side, which will slow the overall diurnal mixing, however
should still be able to reach afternoon highs very close to
climatology in the 59-64 range. Sunday night the surface ridge will
exit to our east allowing a slow increase in gradient and also low
level moisture. Current guidance still suggest a cool overnight with
lows in the mid 30s inland to the low 40s at the coast.
Monday,
Stacked ridging will allow temperatures to finally rise above
normal for most locations. Still not anticipating all that efficient
a mixing environment, and therefore will likely not realize the full
potential of the column that 850mb temps around 10C would suggest.
However, not too many will be complaining as temps rise into the
upper 60s to near 70 under partly sunny skies. The SE/S flow is
likely to keep immediate coastal areas a bit cooler, especially
along the Apalachee Bay coastline where shelf water temps are in
the upper 50s.
&&
.LONG TERM (Monday Night through next Friday)...
The large scale longwave pattern commences fairly amplified. This is
highlighted in the Nrn stream by troughing across Plains and weak
ridging in between. Srn stream with weak troughing Desert SW and
weak ridging elsewhere. At surface, high along Carolina coast
ridging swwd into Cntrl Gulf. Low in Srn Great Lakes with cold front
Swwd across Wrn TN Valley and into TX.
During the rest of the period, Plains upper trough digs rapidly SEWD
accompanied by shortwave and merges with Desert SW Trough crossing
the Nrn Gulf Tues into Tues night. In response, Srn stream upper
ridge shunted offshore. At surface, this trough pushes surface low
to Srn Great Lakes kicking high further into Atlc. Assocd cold front
with limited instability dragged rapidly Sewd with deep sly flow
setup from Gulf. GFS and ECMWF similar in timing and intensity of
front, but both noticeably slower than 24 hrs ago, pushing thru Wrn
CWA late Tues night exiting Ern most zones Wed morning bringing sct
shwrs and possibly a few tstms.
Trough pushes into Atlc beginning Wed night. In its wake, NWLY to
weakly zonal steering flow once again dominates local area as
strong high builds SEWD from Srn Plains spreading a reinforcing shot
of cold and very dry offshore air across local region Wed into late
Thurs. However coldest air remains well to our north so not
expecting a solid freeze event. By early Fri, models consistent with
next albeit weak shortwave that helps developing surface low which
moves moves newd into Lwr MS Valley dragging trailing cold front to
Wrn Gulf. Locally, this pushes the dry airmass EWD and high offshore
increasing onshore flow and clouds beginning Fri night.
Forecast will show low-mid sct pops Tues aftn especially NW third
expanding everywhere on Wed morning down to wdly sct-low sct Wed
aftn. Otherwise nil pops thru period. Ahead of the front min temps
will be around 10 degrees above climo Mon and Tues nights dropping
to at or below climo Wed night and may reach freezing in coldest
locales then inching to slightly above climo on Thu night. Max temps
commence at least 10 degrees above climo on Tues dropping to at or
slightly above climo on Wed then inching up to a few degrees each
day thru Fri. Average inland min/max temps are 39/62
&&
.MARINE...
High pressure will build over the coastal waters today allowing
winds and seas to subside. A brief surge of westerly winds may
approach cautionary levels overnight into early Sunday morning
before quickly diminishing by the afternoon. The ridge of high
pressure will then move east of our region Sunday night allowing
winds to come around to the east and southeast and increase to
moderate levels for the early portion of next week. A weak cold
front is schedule to cross the northeast Gulf Tuesday night or
Wednesday with a shift back to offshore flow in its wake.
&&
.AVIATION (through 12Z Sunday)...
VFR Conditions with mainly clear skies through the period. Calm
winds increase to west to northwest around 5 mph after sunrise,
then calm again after sunset.
&&
.FIRE WEATHER...
Expect a faster warmup and higher afternoon temperatures today
compared to yesterday. Therefore with a persistent dry airmass
expect around 4 hour durations of RH below 25% in our Alabama and
Georgia zones, altho ern counties of GA iffy. But...with warning
already in effect will elect to keep it everywhere and have day
shift reevaluate. For our Florida zones, altho critical humidities
will be realized, latest dispersions as well as ERC and 20 foot
winds should remain under critical levels. Therefore inherited watch
has been discontinued. Airmass should moisten slightly on Sunday
precluding red flag conditions over AL/GA. Once again low humidities
in FL will be offset by ERC...dispersion and winds below critical
levels. Red flag conditions are not anticipated during the upcoming
work week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 57 32 62 33 68 / 0 0 0 0 0
Panama City 57 40 62 43 61 / 0 0 0 0 0
Dothan 59 35 59 36 69 / 0 0 0 0 0
Albany 57 32 59 34 70 / 0 0 0 0 0
Valdosta 56 33 60 35 68 / 0 0 0 0 0
Cross City 58 31 64 34 70 / 0 0 0 0 0
Apalachicola 56 36 61 41 60 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Red Flag Warning from Noon today to 5 PM CST this afternoon for
Coffee-Dale-Geneva-Henry-Houston.
GA...Red Flag Warning from 1 PM this afternoon to 6 PM EST this
evening for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-
Colquitt-Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier-
Lee-Lowndes-Miller-Mitchell-Quitman-Randolph-Seminole-
Terrell-Thomas-Tift-Turner-Worth.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
921 AM CST SAT JAN 14 2012
.DISCUSSION...
ISSUED 921 AM CST SAT JAN 14 2012
15Z SURFACE CHART SHOWS 1014MB LOW OVER CENTRAL MISSOURI...WITH
BAND OF LIGHT SNOW NORTH OF THIS FEATURE FROM NORTHERN MISSOURI
INTO SOUTH-CENTRAL ILLINOIS. BASED ON RADAR IMAGERY AND AREA
SURFACE OBS...THE SNOW HAS PRIMARILY BEEN CONFINED TO LOCATIONS
ALONG AND SOUTH OF A MACOMB...TO LINCOLN...TO CHARLESTON-MATTOON
LINE. AS THE LOW TRACKS E/SE...THE BAND OF SNOW WILL CONTINUE TO
IMPACT MAINLY THE SOUTHERN HALF OF THE KILX CWA THROUGH AT LEAST
EARLY AFTERNOON. WEAK LIFT AND LIMITED MOISTURE WILL LIMIT ANY
ACCUMULATIONS TO ONLY A COUPLE TENTHS OF AN INCH AT BEST. FURTHER
NORTHWEST...ANOTHER WEAK SHORT-WAVE IS NOTED IN WATER VAPOR
IMAGERY TRACKING ACROSS THE EASTERN DAKOTAS. THIS FEATURE WILL
APPROACH FROM THE NORTHWEST LATER THIS AFTERNOON INTO THE
EVENING...BRINGING A FEW FLURRIES TO THE AREA. HAVE UPDATED THE
FORECAST FOR TODAY TO INCLUDE 30-40 POPS FOR LIGHT SNOW ACROSS THE
SOUTHERN CWA...WITH JUST SCATTERED FLURRIES TO THE NORTH. HAVE
ADDED FLURRIES ACROSS THE BOARD FOR THE EVENING HOURS IN ASSOCIATION
WITH THE SECONDARY WAVE. ZONE UPDATE HAS ALREADY BEEN ISSUED.
BARNES
&&
.AVIATION...
ISSUED 530 AM CST SAT JAN 14 2012
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WEAK
CLIPPER SYSTEM IS MOVING INTO THE SOUTHERN PARTS OF THE AREA THIS
MORNING. THIS IS BRINGING LOWER VFR CIGS AROUND 5KFT INTO THE
AREA. BELIEVE PRIMARY SITES THAT WILL EXPERIENCE CIGS AT THIS
LEVEL WILL BE SPI AND DEC. PIA/BMI/CMI COULD SEE THIS BUT THEY
WILL BE ON THE NORTHERN EDGE OF THE CIGS. SO WILL HAVE SCATTERED
CLOUDS AT 5KFT WITH TEMPO GROUP FOR 4HRS OF POSSIBLE CIGS AT 5KFT.
EXPECT MID LEVEL CIGS OTHERWISE DURING THE MORNING HOURS AT THREE
SITES ALONG I-74. 5KFT CIGS AT SPI AND DEC SHOULD CONTINUE INTO
THE AFTERNOON HOURS. BY THIS AFTERNOON...APPEARS ALL SITES COULD
BE MOSTLY CLEAR SO WILL HAVE SKC AT ALL SITES STARTING AROUND 21Z.
THIS SHOULD LAST INTO THE EVENING HOURS. HOWEVER WITH A RETURN TO
WAA...EXPECT SOME LOWER VFR CIGS AROUND 4KFT DURING THE LATE
EVENING AND OVERNIGHT HOURS. COULD BE LOWER...BUT WILL START WITH
SCATTERED CLOUDS AT 2.5KFT WITH BKN CIGS AT 4KFT...AT ALL SITES.
WIND DIRECTION WILL BE SOUTHERLY TO START BUT AS THE WEAK CLIPPER
SYSTEM MOVES SOUTH OF THE AREA WINDS WILL BECOME EAST...TO
NORTHEAST...AROUND TO NORTHWEST. HOWEVER...WIND SPEEDS WILL BE
LIGHT SO WILL HAVE VARIABLE WINDS AS WELL DURING AFTERNOON AND
EARLY EVENING HOURS. BY OVERNIGHT...SOUTHERLY WINDS WILL RETURN AGAIN.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 235 AM CST SAT JAN 14 2012
LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND
CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS
BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY
TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE
WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY.
HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO
IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS
SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST
MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN
SHEARING OUT OVER THE CENTRAL PLAINS.
PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES
TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY.
SHORT TERM...TODAY THROUGH TUESDAY...
SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST
NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE
SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE
WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH
THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT
QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A
GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS
INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND
KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER
CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH.
SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY
TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO
FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON
THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH
MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL
INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS
BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING
THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY
NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A
QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT
MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH
OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY
THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE
TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL
CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH
THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF
THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL
CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT
CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES
SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER
SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS
KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE
WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN
THE PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
530 AM CST SAT JAN 14 2012
.DISCUSSION...
ISSUED 235 AM CST SAT JAN 14 2012
LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND
CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS
BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY
TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE
WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY.
HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO
IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS
SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST
MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN
SHEARING OUT OVER THE CENTRAL PLAINS.
PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES
TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY.
SHORT TERM...TODAY THROUGH TUESDAY...
SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST
NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE
SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE
WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH
THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT
QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A
GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS
INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND
KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER
CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH.
SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY
TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO
FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON
THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH
MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL
INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS
BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING
THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY
NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A
QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT
MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH
OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY
THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE
TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL
CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH
THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF
THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL
CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT
CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES
SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER
SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS
KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE
WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN
THE PERIOD.
GEELHART
&&
.AVIATION...
ISSUED 530 AM CST SAT JAN 14 2012
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WEAK
CLIPPER SYSTEM IS MOVING INTO THE SOUTHERN PARTS OF THE AREA THIS
MORNING. THIS IS BRINGING LOWER VFR CIGS AROUND 5KFT INTO THE
AREA. BELIEVE PRIMARY SITES THAT WILL EXPERIENCE CIGS AT THIS
LEVEL WILL BE SPI AND DEC. PIA/BMI/CMI COULD SEE THIS BUT THEY
WILL BE ON THE NORTHERN EDGE OF THE CIGS. SO WILL HAVE SCATTERED
CLOUDS AT 5KFT WITH TEMPO GROUP FOR 4HRS OF POSSIBLE CIGS AT 5KFT.
EXPECT MID LEVEL CIGS OTHERWISE DURING THE MORNING HOURS AT THREE
SITES ALONG I-74. 5KFT CIGS AT SPI AND DEC SHOULD CONTINUE INTO
THE AFTERNOON HOURS. BY THIS AFTERNOON...APPEARS ALL SITES COULD
BE MOSTLY CLEAR SO WILL HAVE SKC AT ALL SITES STARTING AROUND 21Z.
THIS SHOULD LAST INTO THE EVENING HOURS. HOWEVER WITH A RETURN TO
WAA...EXPECT SOME LOWER VFR CIGS AROUND 4KFT DURING THE LATE
EVENING AND OVERNIGHT HOURS. COULD BE LOWER...BUT WILL START WITH
SCATTERED CLOUDS AT 2.5KFT WITH BKN CIGS AT 4KFT...AT ALL SITES.
WIND DIRECTION WILL BE SOUTHERLY TO START BUT AS THE WEAK CLIPPER
SYSTEM MOVES SOUTH OF THE AREA WINDS WILL BECOME EAST...TO
NORTHEAST...AROUND TO NORTHWEST. HOWEVER...WIND SPEEDS WILL BE
LIGHT SO WILL HAVE VARIABLE WINDS AS WELL DURING AFTERNOON AND
EARLY EVENING HOURS. BY OVERNIGHT...SOUTHERLY WINDS WILL RETURN AGAIN.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
522 AM CST SAT JAN 14 2012
...UPDATE TO AVIATION...
&&
.AVIATION...
VFR ANTICIPATED THROUGH THE PERIOD. WINDOW OF GUSTY WINDS
NORTHWEST BEGINS AROUND TAF ISSUANCE AND CONTINUES INTO THE EARLY
AFTERNOON HOURS. CIGS NEAR 3KFT AGL EXPECTED TO BE SLIGHTLY HIGHER
AND NOT A SOLID DECK AS THEY MOVE OVER TOP/FOE/MHK BUT WILL
MONITOR FOR UPDATES. WINDS DROP BLO 12KTS 20-21Z THEN BECOME
WESTERLY TO SOUTHWESTERLY THIS EVENING AND OVERNIGHT. 67
&&
.PREV DISCUSSION...
/ISSUED 331 AM CST SAT JAN 14 2012/
SHORT RANGE (TODAY AND SUNDAY)...
09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD
UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A
STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN
THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL
PLAINS. WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH
EMBEDDED WITHIN THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT
EXPECT TO SEE MANY EFFECTS FROM THIS WAVE SHORT OF SOME PASSING
LOW TO MID CLOUDS EARLY THIS MORNING. BY MID MORNING TO EARLY
AFTERNOON THE WAVE WILL MOVE THROUGH THE AREA AND SUBSIDENCE WILL
TAKE OVER BRINGING MOSTLY CLEAR CONDITIONS. AT THE SURFACE A
FAIRLY STRONG RIDGE HAS SET UP IN THE WESTERN HIGH PLAINS AND HAS
CREATED A DECENT PRESSURE GRADIENT BETWEEN ITSELF AND A WEAK
SURFACE TROUGH WHICH IS CURRENTLY LOCATED IN FAR SE NEBRASKA. AS A
RESULT OF THE GRADIENT BETWEEN THESE TWO FEATURES EXPECT WEST-
NORTHWEST WINDS TO PICK UP IN INTENSITY THROUGHOUT THE DAY
LENDING TO SOME WEAK COLD AIR ADVECTION. HOWEVER WITH LOWS
STARTING OUT A BIT WARMER THAN YESTERDAY AND WITH GOOD INSOLATION
EXPECT TEMPS TO CREEP INTO THE UPPER 40S AND LOWER 50S ACROSS
NORTHEAST KANSAS FOR TODAY. BUMPED MIN TEMPS FOR SUNDAY UPWARD A
LITTLE AS WINDS BACK AROUND TO THE WEST-SOUTHWEST OVERNIGHT AND
PICK UP EARLY SUNDAY MORNING...CREATING SOME WEAK WARM AIR
ADVECTION AND KEEPING TEMPS A BIT WARMER. SUNDAY WILL LIKELY BE
THE NICEST DAY OF THE FORECAST PERIOD...AS STRONG SOUTHERLY WINDS
AND A FLEETING UPPER RIDGE PUSHES THROUGH THE AREA. GIVEN THOSE
TWO FACTORS AS WELL AS GOOD INSOLATION DUE TO CLEAR SKIES EXPECT
TEMPS TO REACH INTO THE LOWER 60S ON SUNDAY.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)...
THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES
INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS
AHEAD OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE
COULD HAVE ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS
ON MONDAY COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD
FRONT TO BE SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY
MEANING AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY ONLY
RISE INTO THE 40S ON MONDAY. A QUICKLY MOVING UPPER WAVE WILL
ALSO PUSH THROUGH THE NORTHERN PLAINS ON MONDAY NIGHT...AND
PERHAPS COULD BRING A PERIOD OF VERY LIGHT SNOW TO AREAS NORTH OF
HIGHWAY 24 ON MONDAY NIGHT. WITH NOT MUCH MOISTURE TO WORK WITH
DO NOT EXPECT MORE THAN A TENTH OR TWO OF SNOW ACCUMULATION FROM
THIS SYSTEM. TUESDAY WILL BE RATHER CHILLY AS THE ARCTIC AIRMASS
TAKES HOLD OF THE AREA...BUT BY WEDNESDAY WEST-SOUTHWEST WINDS
WILL RETURN TO THE AREA BRINGING ANOTHER GENTLE WARM UP. MODELS
THEN HINT AT FRIDAY BEING ANOTHER UNSEASONABLY WARM DAY. SOUTH-
SOUTHWEST WINDS WITH A VERY WARM AIRMASS LOOK TO MAKE THEIR WAY
INTO NORTHEAST KANSAS ON FRIDAY. WILL CURRENTLY STICK WITH TEMPS
IN THE UPPER 40S TO LOWER 50S FOR FRIDAY...BUT IF MODELS CONTINUE
TO TREND TOWARD A WARMER SOLUTION WILL BUMP THOSE TEMPS UP AS
THAT DAY APPROACHES.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
800 AM EST SAT JAN 14 2012
.SYNOPSIS...
COLD UPPER LEVEL LOW PRESSURE, PASSING SLOWLY EASTWARD THROUGH THE
GREAT LAKES, WILL MAINTAIN COLD CONDITIONS AND LIGHT SNOW SHOWERS
TODAY. MIDWEST HIGH PRESSURE WILL PROVIDE A DRY SUNDAY AND EARLY
MONDAY. CANADIAN LOW PRESSURE WILL FIRST BRING A WARM UP WITH RAIN
SHOWERS LATE MONDAY AND TUESDAY, FOLLOWED BY A COOL DOWN WITH SNOW
SHOWERS TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FOR MINOR ADJUSTMENTS TO POPS. RECENT SATELLITE DATA
SHOWS CLOUD TOPS WARMING AND LIKEWISE RECENT RADAR AND SURFACE
DATA SHOW SNOW FALL RATES HAVE DECREASED. WITH HRRR AND NAM MODEL
OUTPUT SHOWING LITTLE SNOW REJUVENATION, EXPECT SLOW DECREASE THIS
MORNING, WEST TO EAST, WITH PERHAPS A DRY BREAK BY AFTERNOON. SNOW
ACCUMULATIONS WILL BE MINIMAL.
PER BLEND OF RECENT GFS AND NAM MOS, FORECASTED TEMPERATURES THIS
AFTERNOON TO CLIMB TO HIGHS THAT WILL STILL BE 7 TO 12 DEGREES
COLDER THAN NORMAL.
NAM MODEL PROFILES SHOW WINDS DECREASING TO NORMAL VALUES BY
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
RECENT SREF MODEL OUTPUT SHOWS ONE MORE UPPER LEVEL TROUGH PASSING
THROUGH THE UPPER OHIO VALLEY THIS EVENING. EXPECT MAINLY ISOLATED
SNOW SHOWERS ACROSS THE MOUNTAINS WITH NO MORE THAN FLURRIES
ELSEWHERE.
AS UPPER TROUGH EXITS EAST, MIDWEST HIGH PRESSURE ENSUES TO PROVIDE
A DRY SUNDAY.
PER BLEND OF RECENT GFS AND NAM MOS, FORECASTED TEMPERATURES TONIGHT
TO YIELD LOWS 5 TO 8 DEGREES COLDER THAN NORMAL. HIGHS SUNDAY MAY BE
SLIGHTLY WARMER THAN TODAY, BUT STILL GENERALLY ABOUT 5 TO 8 DEGREES
COLDER THAN NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
RECENT SREF MODEL OUTPUT SHOWS HIGH PRESSURE MAINTAINING DRY
CONDITIONS SUNDAY NIGHT INTO MONDAY.
BLEND OF RECENT ECMWF AND GFS MODEL OUTPUT SHOWS THE ROBUST UPPER
LEVEL JETSTREAM ACROSS NORTH AMERICA WILL THEN STEER A LOW PRESSURE
SYSTEM EASTWARD THROUGH THE GREAT LAKES AND MIDWEST MONDAY NIGHT
INTO WEDNESDAY. WEST TO SOUTHWEST WINDS AHEAD OF THE SYSTEM`S COLD
FRONT WILL PROVIDE A WARM UP MONDAY, SO THE INITIAL PRECIPITATION
TYPE SHOULD BE RAIN SHOWERS MONDAY NIGHT AND TUESDAY.
MODELS THEN SHOW A POST FRONTAL COOL DOWN WITH SNOW SHOWERS TUESDAY
NIGHT INTO POSSIBLY WEDNESDAY. ANOTHER CANADIAN COLD FRONTAL PASSAGE
MAY PROVIDE SNOW SHOWERS THURSDAY.
REGARDING TEMPERATURE DETAILS, BLEND OF RECENT GFS MOS AND NAEFS
MEDIAN VALUES SHOW THE WARM UP MONDAY INTO TUESDAY TO YIELD VALUES
10 TO 15 DEGREES WARMER THAN NORMAL. THE POST FRONTAL COOL DOWN
STARTING TUESDAY NIGHT WILL YIELD VALUES 5 TO 10 DEGREES COLDER
THAN NORMAL, THAT COULD LAST INTO FRIDAY.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
EXPECT MAINLY MVFR CONDITIONS INTO TONIGHT, MAINLY DUE TO
STRATOCUMULUS CEILINGS.
AS ONE UPPER LEVEL SHORT-WAVE TROUGH EXITS EAST, RECENT SATELLITE
DATA SHOWS WARMING TOPS AND SURFACE AND RADAR DATA SHOW SNOW FALL
RATES HAVE SLOWED. SO VISIBILITIES CAN BE UNRESTRICTED AT TIMES
TODAY.
A SECOND UPPER LEVEL SHORT-WAVE TROUGH CAN PASS EASTWARD THROUGH
THE UPPER OHIO VALLEY THIS EVENING. THIS MAY CAUSE SCATTERED LIGHT
SNOW SHOWERS WITH VISIBILITIES POSSIBLY RESTRICTED.
SURFACE WINDS WILL BE MAINLY WEST SOUTHWEST NEAR 10 KTS WITH GUSTS
TO 20 KTS INTO MIDDAY.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
EXPECT MAINLY VFR SUNDAY INTO MIDDAY MONDAY. NEXT CHANCE OF
RESTRICTIONS WILL BE LATE MONDAY INTO WEDNESDAY FROM MIXED
PRECIPITATION ASSOCIATED WITH A LOW PRESSURE SYSTEM PASSING EASTWARD
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1002 AM CST SAT JAN 14 2012
.DISCUSSION...
MINOR UPDATE TO WINDS AND PRECIP WERE MADE. BASED ON SFC WIND
FIELD WK SFC LOW JUST WEST OF WINNIPEG...WITH WEST WIND SHIFT
THROUGH WALHALLA-CAVALIER THEN TO GRAND FORKS AIR FORCE BASE (AS
OF 1543Z) THEN TO JUST WEST OF FARGO-WAHPETON TO WHEATON. SFC LOW
WILL CONTINUE TO MOVE SLOWLY SOUTHEAST TOWARD BAUDETTE BY 21Z-00Z
AND WITH IT WIND WILL GRADUALLY SHIFT TO THE WEST AS BOUNDARY
MOVES THROUGH. WARMER AIR BEHIND IT WITH TEMPS IN THE MID 20S. FAR
NORTHEAST MAY NEVER QUITE GET INTO THE 20S SO LOWERED A BIT
THERE...OTHERWISE ADJUSTED CURVE A BIT BUT KEPT HIGHS IN THE MID
20S FOR THE MOST PART...WITH SOME READINGS NEAR 30 IN FAR
SOUTHWEST FCST AREA WHERE SOME SUNNY BREAKS WILL OCCUR. OTHERWISE
SATELLITE SHOWS PLENTY OF CLOUDS MOVING SOUTHEAST SO EXPECT
MAJORITY OF THE FCST AREA TO REMAIN IN THE CLOUDS. KEPT FLURRIES
OR LIGHT SNOW IN FOR NORTHEAST 1/2 OF FCST AREA THRU THE DAY AS
UPSTREAM CANADIAN RADAR SHOWS LIGHT ECHOES UP TO DAUPHIN MANITOBA.
&&
,AVIATION...
CIGS WILL REMAIN MOSLY VFR FAR-GFK-DVL THRU THE DAY. TVF-BJI WILL
SEE MVFR CIGS GRADUALLY BECOME VFR IN LIGHT SNOW.
&&
.PREV DISCUSSION... /ISSUED 230 AM CST SAT JAN 14 2012/
DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES
TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR
DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL
USE BLEND.
BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND
WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON
CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND
THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER
OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS
BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE
LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES
FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST
AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE
BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION
LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY.
FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN
THE 20S.
TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY
MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND
WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN
CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE.
NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN
BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF
FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG
WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY
OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS
COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED
32 DEGREES.
STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT
INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE
BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS
FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY
TO RECOVER AT ALL MONDAY AND MAY EVEN DROP.
LONG TERM (TUE-FRI)...
MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC
AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO
NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT
SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK
FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/VOELKER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
642 AM EST SAT JAN 14 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP INTO NORTHERN PENNSYLVANIA TODAY. HIGH
PRESSURE WILL RETURN ON SUNDAY AND BRING MODERATING TEMPERATURES
AGAIN BY EARLY NEXT WEEK. LOW PRESSURE WILL MOVE INTO THE GREAT
LAKES TUESDAY AND CREATE PERIODS OF RAIN DURING THE MIDDLE OF THE
WEEK...PERHAPS STARTING AS A WINTRY MIX. A COLD FRONT WILL PUSH
ACROSS THE STATE AND DROP TEMPERATURES BACK TO NEAR OR SLIGHTLY
BELOW NORMAL FOR WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVERGENCE IN TWO MAIN AREAS NOW WITH WRLY FLOW CREATING A BAND
THROUGH NERN OH AND ANOTHER BAND ORIENTED MORE WSW-ENE JUST TO THE
NORTH OF WARREN AND MCKEAN COS. GENERAL UPSLOPE AND LIFT OF A
MINOR SHORT WAVE TROUGH OVER SWRN PA IS CREATING SHSN IN THE
LAURELS. THE FLOW IS EXPECTED TO CONTINUE TO VEER THROUGH THE
REST OF THE NIGHT AND EARLY SAT AM. THIS SHOULD HELP THE LAKE
EFFECT BANDS TO SAG INTO OUR NWRN COUNTIES. ACCUMS WILL MAINLY
STAY UNDER 2 INCHES IN THE WHOLE AREA THROUGH 7 AM.
A WEAK BACKDOOR FRONT IS PROGGED BY THE NAM AND HRRR TO SAG
SOUTHWARD AND CROSS THE NY BORDER DURING THE MORNING...AND BECOME
A FOCUS FOR SHSN - PROVIDING A PATHWAY FOR AT LEAST ONE LONG LAKE
EFFECT BAND TO CROSS ALL THE NRN TIER COS. INVERSION HEIGHTS STAY
HIGH ALL DAY LONG...SO THOSE BAND/S WILL HAVE THE GOOD DENDRITES IN
THEM...WITH A GOOD PORTION OF THE CLOUD -10C TO -20C. WILL UP
SNOW AMTS AN INCH OR TWO FOR THE DAYTIME ON SAT UP NORTH.
BUT...FOR NOW KEEP IT JUST BELOW ADVY CRITERIA. WILL CONT THE LK
SNOW WARN.
WHILE THE OVERNIGHT LOWS WILL BE MUCH CHILLIER THAN RECENT
NIGHTS...THEY WILL STILL AVERAGE VERY NEAR OR EVEN SLIGHTLY ABOVE
NORMAL FOR THE SECOND WEEK OF JANUARY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
HIGH PRESSURE SLOWLY WORKS IN SAT NIGHT...WITH A GRADUAL END TO
THE LAKE BANDS. WILL KEEP LIKELIES THRU MIDNIGHT FOR THE NW...BUT
DECREASE THEM ELSEWHERE. CLEARING COULD TAKE A WHILE AS WELL AS 8H
FLOW DOES NOT CHANGE TO SW UNTIL MID NIGHT. BY SUNRISE EXPECT
MAINLY CLEAR SKIES. SUNDAY LOOKS FAIRLY DRY WITH INCREASE IN
CLOUDS FROM THE WEST WITH HIGH PRESSURE OVERHEAD. TEMPS LOOK TO
STAY JUST SUB-NORMAL THRU THE SHORT TERM PD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
ARCTIC BOUNDARY WILL LIKELY SLIP SOUTH INTO CENTRAL PENN AND THE
SUSQ VALLEY SAT NIGHT AND SUNDAY. THIS FEATURE ALONG WITH DEEP
WNW TO NW FLOW ALOFT WILL MAINTAIN AT LEAST SCATTERED SNOW
SHOWERS ACROSS THE NW MTNS. A FEW NARROW...BUT RATHER LENGTHY
BANDS OF SNOW SHOWERS COULD EXTEND INTO THE CENTRAL MTNS AND EVEN
THE SUSQ VALLEY NEAR THIS BOUNDARY. CLOUD TOP TEMPS AROUND 5-6 KFT
AGL WILL BE QUITE COLD AND AT THE LOWER END OF THE THERMAL RIBBON
FOR DENDRITIC GROWTH...LEADING TO LOCALIZED ACCUMS OF A FLUFFY
INCH OR TWO.
THIS FRONT COULD SETTLE INTO SRN PENN VERY BY DAYBREAK SUNDAY
WITH SOME PERIODS OF CLEARING POSSIBLE NEAR THE NY STATE LINE.
THIS MAY LEAD TO MIN TEMPS EARLY SUNDAY NEAR ZERO ACROSS THE
NORTH...WITH TEMPS IN THE LOWER TO MID TEENS AND GENERALLY PARTLY
CLOUDY AND DRY CONDITIONS THROUGHOUT THE VALLEYS TO THE SOUTH OF
INTERSTATE 80.
THE SFC RIDGE AXIS WILL SLIDE INTO EASTERN PENN LATE SUNDAY AND
EARLY SUNDAY NIGHT. THE BEST CHC FOR CLEAR SKIES WILL BE OVER THE
EASTERN HALF OF THE CWA. WANING LAKE EFFECT...AND SHALLOW/UPSLOPE
STRATO CU INTO EARLY SUNDAY AFTERNOON /ACROSS MAINLY THE NRN AND
WRN MTNS/ WILL BE FOLLOWED BY INCREASING WAA ALOFT AND SOME ALTO CU
BY LATER SUNDAY NIGHT.
MONDAY WILL BE THE TRANSITION DAY. THE SFC HIGH WILL SLIDE OFF THE
EAST COAST BY MONDAY AFTERNOON WITH DEEP WSWRLY FLOW
DEVELOPING...PUSHING WELL ABOVE NORMAL TEMPS AND LIKELY SOME
RAIN SHOWERS BACK INTO THE REGION FOR TUESDAY...AS 850 TEMPS CLIMB
TO PLUS 3-6C ACROSS MUCH OF THE CWA.
THE BEST CHC FOR RAIN/SHOWERS LOOKS TO BE TUESDAY INTO EARLY
TUESDAY NIGHT IN THE RELATIVELY HIGH PWAT AIR OF 0.75-1.00 INCH
AHEAD OF AN APPROACHING CFRONT.
COLDER AIR WILL SURGE EAST ACROSS THE STATE TUESDAY NIGHT/EARLY
WEDNESDAY WITH A RETURN TO DEEP WNW FLOW AND MTN SNOW
SHOWERS WITH A 12-24 HOUR WINDOW OF LES POSSIBLE INTO WEDNESDAY
NIGHT.
NEAR TO SLIGHTLY BELOW NORMAL TEMPS AND MAINLY DRY CONDITIONS WILL
OCCUR LATE NEXT WEEK...AS JUST A FEW WEAK SHORTWAVES WITH FLURRIES
OR SCATTERED SNOW SHOWERS DROPS SE FROM THE GREAT LAKES.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SFC ANALYSIS SHOWS A SECONDARY ARCTIC FRONT ACRS CNTRL NY THIS
MRNG...WHICH WILL SINK SWD INTO NRN PA THIS AFTN. HI RES MDL GUID
SHOWS LOW LEVEL CONVERGENCE ALONG THE FRONT HELPING TO ORGANIZE A
LONG-FETCH LAKE EFFECT BAND NEAR ERI-BFD-IPT LINE THIS AFTN. THE
EXACT LOCATION OF WHERE THE BAND WILL FORM AND HOW FAR SOUTH IT
WILL PROPAGATE IS STILL UNCERTAIN...BUT GIVEN THE CONSENSUS OF THE
HI RES DATA INDICATING PROXIMITY OF NRN TIER OF PA - REDUCED IPT
VIS TO MVFR AT 18Z. UNV MAY ALSO BE IMPACTED LATER TDY BUT FOR
NOW KEPT VIS VFR. OVERALL THERE ARE NO SIGNIFICANT CATEGORICAL
CHANGES TO 09Z INTERMEDIATE TAFS FOR THE 12Z SCHEDULED ISSUANCE.
COLD CCW FLOW COMBINED WITH ADNL UPPER LEVEL ENERGY CROSSING THE
GREAT LKS REGION WILL CONTINUE LAKE EFFECT AND UPSLOPE SNOW
SHOWERS. THE WORST FLYING CONDS WILL PERSIST ACROSS THE WRN
MTNS...WHERE VSBYS WILL BE REDUCED TO 1-3SM AT BFD AND JST.
DOWNSLOPING FLOW E OF THE MTNS WILL RESULT IN ONLY SCT
FLURRIES IN MOST AREAS...WITH MVFR CIGS BCMG VFR AT UNV/AOO AND
LOW END SCT-BKN VFR CIGS AT LNS/MDT/IPT. SFC WNDS WILL GRADUALLY
VEER MORE TO THE WNW INTO TONIGHT.
OUTLOOK...
SUN...MVFR CIGS WEST...BCMG VFR.
MON...VFR BCMG MVFR MON NGT. LGT WINTRY MIX TO RAIN.
TUES...MVFR/IFR. STG FROPA WND SFT. GUSTY WINDS. -RA TO -SHSN.
WED...MVFR/IFR -SHSN WEST/VFR EAST. WINDY.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ004-005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/STEINBUGL
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1136 AM CST SAT JAN 14 2012
.DISCUSSION...
ISSUED 921 AM CST SAT JAN 14 2012
15Z SURFACE CHART SHOWS 1014MB LOW OVER CENTRAL MISSOURI...WITH
BAND OF LIGHT SNOW NORTH OF THIS FEATURE FROM NORTHERN MISSOURI
INTO SOUTH-CENTRAL ILLINOIS. BASED ON RADAR IMAGERY AND AREA
SURFACE OBS...THE SNOW HAS PRIMARILY BEEN CONFINED TO LOCATIONS
ALONG AND SOUTH OF A MACOMB...TO LINCOLN...TO CHARLESTON-MATTOON
LINE. AS THE LOW TRACKS E/SE...THE BAND OF SNOW WILL CONTINUE TO
IMPACT MAINLY THE SOUTHERN HALF OF THE KILX CWA THROUGH AT LEAST
EARLY AFTERNOON. WEAK LIFT AND LIMITED MOISTURE WILL LIMIT ANY
ACCUMULATIONS TO ONLY A COUPLE TENTHS OF AN INCH AT BEST. FURTHER
NORTHWEST...ANOTHER WEAK SHORT-WAVE IS NOTED IN WATER VAPOR
IMAGERY TRACKING ACROSS THE EASTERN DAKOTAS. THIS FEATURE WILL
APPROACH FROM THE NORTHWEST LATER THIS AFTERNOON INTO THE
EVENING...BRINGING A FEW FLURRIES TO THE AREA. HAVE UPDATED THE
FORECAST FOR TODAY TO INCLUDE 30-40 POPS FOR LIGHT SNOW ACROSS THE
SOUTHERN CWA...WITH JUST SCATTERED FLURRIES TO THE NORTH. HAVE
ADDED FLURRIES ACROSS THE BOARD FOR THE EVENING HOURS IN ASSOCIATION
WITH THE SECONDARY WAVE. ZONE UPDATE HAS ALREADY BEEN ISSUED.
&&
.AVIATION...
ISSUED 1136 AM CST SAT JAN 14 2012
LIGHT SNOW WILL CONTINUE TO IMPACT MOST OF THE TAF SITES FOR THE
NEXT COUPLE OF HOURS...BEFORE GRADUALLY COMING TO AN END BY
MID-AFTERNOON. WILL HANG ON TO LIGHT SNOW THROUGH 19Z/20Z
ACCORDINGLY...EXCEPT AT KPIA WHERE THE SNOW HAS ALREADY ENDED.
CEILINGS WILL HOVER AROUND 3000FT AT THE I-72 TERMINALS UNTIL THE
SNOW ENDS...THEN WILL CLIMB INTO THE VFR CATEGORY LATER THIS
AFTERNOON. A SECONDARY UPPER-LEVEL WAVE CURRENTLY PUSHING INTO
IOWA WILL SKIRT THROUGH THE REGION TONIGHT...BRINGING A PERIOD OF
LOWER CEILINGS AND PERHAPS A FEW SNOW FLURRIES. HAVE LOWERED
CEILINGS BACK DOWN TO AROUND 3000FT AT KPIA BY 03Z...THEN FURTHER
EAST AT KCMI BY 08Z. ONCE THIS WAVE PASSES...MID-LEVEL CLOUD COVER
WILL PERSIST THROUGH 18Z SAT. WINDS WILL INITIALLY BE
LIGHT/VARIABLE THIS AFTERNOON AND TONIGHT...THEN WILL BECOME
SOUTHERLY AT AROUND 10KT SUNDAY MORNING.
BARNES
&&
.PREV DISCUSSION...
ISSUED 235 AM CST SAT JAN 14 2012
LAST OF THE STRATOCUMULUS DECK AND FLURRIES LINGER AROUND
CHAMPAIGN AND DANVILLE AT 08Z...WITH SOME HIGHER ALTOCUMULUS
BEGINNING TO SPREAD ACROSS THE WESTERN CWA. TEMPERATURES QUICKLY
TANKED SHORTLY AFTER SKIES CLEARED...WITH SINGLE DIGITS ACROSS THE
WEST AND A REPORT OF -3 DEGREES IN NORTHERN KNOX COUNTY.
HOWEVER...HAVE BEEN SEEING TEMPERATURES RISING THE LAST HOUR OR SO
IN THE WEST AS SOUTHERLY WINDS START TO PICK UP. RADAR MOSAICS
SHOWING SOME LIGHT SNOW ACROSS CENTRAL IOWA AND NORTHWEST
MISSOURI...ASSOCIATED WITH A WEAK CLIPPER SYSTEM THAT HAS BEEN
SHEARING OUT OVER THE CENTRAL PLAINS.
PRIMARY FORECAST CONCERNS FOR THIS CYCLE INCLUDE SNOW CHANCES
TODAY...AND ADDITIONAL PRECIPITATION CHANCES MONDAY-TUESDAY.
SHORT TERM...TODAY THROUGH TUESDAY...
SURFACE LOW WITH THE CLIPPER CURRENTLY CENTERED OVER SOUTHEAST
NEBRASKA...AND PROGGED TO TAKE A TRACK SOUTH OF US TO NEAR THE
SOUTHERN TIP OF ILLINOIS BY MIDDAY. PRIMARY 00Z MODELS ARE QUITE
WEAK WITH ANY SNOW. THE CURRENT HRRR INITIALIZED MUCH BETTER WITH
THE CURRENT ACTIVITY AND MOSTLY FOLLOWED ITS SOLUTION...BUT NOT
QUITE AS FAR EAST...WITH AROUND A QUARTER INCH OF SNOW SOUTH OF A
GALESBURG TO LAWRENCEVILLE LINE THIS MORNING. LINGERED 30 POPS
INTO THE SOUTHEAST THIS AFTERNOON WITH THE ORIGINAL CLIPPER...AND
KEPT SOME SLIGHT CHANCES EVERYWHERE ELSE AS ANOTHER CLIPPER
CURRENTLY ACROSS CENTRAL NORTH DAKOTA PASSES TO OUR NORTH.
SURFACE RIDGING TO QUICKLY MOVE ACROSS THE MID-MISSISSIPPI VALLEY
TONIGHT...WITH A DECENT SOUTHERLY FLOW FOR SUNDAY. CONTINUED TO
FAVOR THE COOLER GUIDANCE FOR HIGHS ON SUNDAY DUE TO THE SNOW ON
THE GROUND. WILL SEE QUITE A BIT OF SNOWMELT SUNDAY THROUGH
MONDAY...WITH HIGHS BRIEFLY BACK INTO THE 40S. COLD FRONT WILL
INTENSIFY TO OUR WEST ON MONDAY...WITH GENERAL MODEL CONSENSUS
BRINGING IT INTO THE NORTHWEST CWA BY SUNSET MONDAY...AND EXITING
THE SOUTHEAST BY SUNRISE TUESDAY. KEPT THE HIGHEST POPS ON MONDAY
NIGHT ACROSS THE EAST. SOLID COLD AIR ADVECTION SHOULD RESULT IN A
QUICK TRANSITION FROM RAIN TO SNOW OVER MOST OF THE CWA...BUT IT
MAY TAKE UNTIL LATE TUESDAY MORNING FOR THE SOUTHEAST TO SWITCH
OVER. WENT WITH STEADY OR SLOWLY FALLING TEMPERATURES FOR TUESDAY.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
FAST UPPER LEVEL WEST-NORTHWEST FLOW EXPECTED ACROSS THE COUNTRY
THROUGH THE MIDDLE AND END OF THE WEEK. UNFORTUNATELY...THESE
TYPES OF FLOWS CAUSE DIFFICULTIES WITH GETTING ANY KIND OF MODEL
CONSENSUS GOING. MAIN CONCERN IN THIS TIME FRAME IS WITH
THURSDAY. GFS IS MOST AGGRESSIVE IN PUSHING A FRONT WELL SOUTH OF
THE AREA BY THIS TIME...WHILE THE ECMWF HAS IT OVER THE CENTRAL
CWA AND THE CANADIAN MODEL KEEPS IT WELL NORTH. HAVE KEPT SLIGHT
CHANCE POPS ON THURSDAY AS A NOD TOWARD THE ECMWF. DIFFERENCES
SIGNIFICANTLY WIDEN ON FRIDAY WITH THE ECMWF SHOWING A MUCH WETTER
SCENARIO AS A LOW LIFTS NORTHEAST FROM ARKANSAS...WHILE THE GFS
KEEPS A DRIER SOUTHERLY FLOW GOING THROUGH THE FIRST PART OF THE
WEEKEND. THUS...CONFIDENCE IN THE FORECAST DIMINISHES BY LATE IN
THE PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
330 PM CST SAT JAN 14 2012
.SYNOPSIS...
A COUPLE OF CLIPPER TYPE SYSTEMS WERE RESPONSIBLE FOR SOME LIGHT
SNOW OVER THE REGION THIS MORNING AND THIS AFTERNOON. THE SURFACE
LOW ASSOCIATED WITH ONE OF THE SYSTEM PASSED JUST TO OUR SOUTH THIS
MORNING SPREADING SOME LIGHT SNOW OVER THE SOUTHERN COUNTIES.
ANOTHER LOW WAS MOVING THOUGH NORTHERN MN EARLY THIS AFTERNOON WITH
A WARM FRONT EXTENDING SOUTH INTO WESTERN IOWA. SOME LIGHT SNOW AND
FLURRIES WERE OCCURRING JUST AHEAD OF THE FRONT. THE CLIPPER TYPE
SYSTEMS WERE EMBEDDED IN NORTHWEST FLOW BOUNDED BY A LARGE TROF OVER
THE GREAT LAKES AND OHIO VALLEY AND RIDGING OVER THE ROCKIES.
ANOTHER VIGOROUS S/W WAS MOVING INTO BRITISH COLUMBIA AND THE
PACIFIC NW WITH 200 METER 12 HOUR HEIGHT FALLS NOTED ON THE MORNING
500MB ANALYSIS.
&&
.SHORT TERM...TONIGHT AND SUNDAY...
THE NORTHERN MN LOW AND ITS ASSOCIATED WARM FRONT WEAKEN THIS
EVENING AS LOW LEVEL FLOW OVER THE CENTRAL AND NORTHERN PLAINS
BACKS AHEAD OF THE PACIFIC NW S/W AND ITS STRONGER SURFACE LOW
MOVING INTO SOUTHERN SASKATCHEWAN BY SUNDAY MORNING. THE LIGHT
SNOW AHEAD OF THE WARM FRONT HAS BEEN STEADILY WEAKENING AS IT
MOVED OVER CENTRAL IOWA THIS AFTERNOON. THE CONTINUATION OF THIS
WEAKENING TREND IS SUPPORTED BY LOW/MID LEVEL FGEN DECREASING
OVER IA AND BECOMING MORE FOCUSED TO OUR NORTH THIS EVENING.
RECENT HRRR RUNS ALSO SUPPORT A BETTER THREAT OF MEASURABLE SNOW
NORTH OF THE CWFA. HAVE CUT POPS BACK TO SLIGHT CHANCE AT MOST...AND
LIMITED THOSE TO THE NORTHEAST THIRD OF THE FORECAST AREA FOR THIS
EVENING. AFTER MIDNIGHT EXPECT PARTLY TO MOSTLY CLOUDY SKIES WITH
MID LEVEL WAA ADVECTION CLOUDS MOVING THROUGH THE AREA AS WELL AS
SOME CI SPREADING IN WITH THE FORECAST AREA IN THE VICINITY OF THE
RIGHT ENTRANCE REGION OF AN H3 JET STREAK FROM MN/WI INTO NRN IN
AT 12Z SUNDAY. SOME FLURRIES WERE CONSIDERED IN THE WEST WITH THE
MID LEVEL WAA...BUT PRESSURE CONDENSATION DEFICITS WERE QUITE HIGH
BELOW 400MB...SO OPTED NOT TO MENTION FLURRIES. TEMPERATURES WILL
BE DIFFICULT WITH THE SNOW COVER...LIGHT WINDS AND PATCHY NATURE
OF THE CLOUDS. ANY CLEARING WILL ALLOW TEMPERATURES TO PLUMMET
OVER THE NORTH. LATEST TIMING OF THE CENTRAL IA CLOUDS INTO/THROUGH
THE CWFA SUGGEST THEY WILL NOT REACH THE EASTERN COUNTIES UNTIL A FEW
HOURS AFTER SUNSET SO ALLOWED FOR A SIGNIFICANT DROP EARLY THIS
EVENING IN NW IL WITH MINS IN THE SINGLE DIGITS.
SUNDAY THE REGION WILL BE DOMINATED BY SOUTHERLY FLOW IN THE LOW
LEVELS AS THE NORTHERN PLAINS SURFACE LOW TRACKS ALONG THE CANADIAN
BORDER AND DRY WESTERLY MID LEVEL FLOW. THIS SHOULD GIVE THE REGION
PLENTY OF SUN. KEPT TEMPERATURES IN THIS REGIME JUST ABOVE GUIDANCE
IN THE SOUTH WHERE LITTLE SNOW COVER EXISTS WITH HIGHS IN THE LOW
40S. OVER THE SNOW COVERED NORTH WENT WITH HIGHS IN THE 30S.
..DLF..
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
SUNDAY NIGHT AND MONDAY...LATEST SUITE OF 12Z RUN MODELS IN
GENERALLY GOOD AGREEMENT THIS PERIOD OF SUGGESTING LEAD IMPULSE OF
PACIFIC NW WAVE ENERGY/SEEN CURRENTLY ON WATER VAPOR IMAGERY
ROTATING DOWN ALONG THE B.C. COAST/ TO RIDGE-RIDE NORTH OF THE U.S.
BORDER ACRS SOUTHERN CANADA AND ACRS JAMES BAY INTO MON. ASSOCIATED
SFC FRONT OFF THIS PASSING WAVE PROBABLY TO JUST MAKE IT ACRS
THE FAR NORTHWESTERN CWA BY 12Z...THUS PRE-FRONTAL WAA AND SOME
BOUNDARY LAYER MOISTURE INCREASE LATE AT NIGHT TO PRODUCE A STEADY
TO SLOW TEMP RISE TOWARD DAWN AND LOWS WILL BE FROM MID EVENING
THROUGH 3 AM CST. 50+ KT SOUTHWESTERLY LLJ TO REALLY WAA AND
PRODUCE A WARM WEDGE/INVERSION ALOFT IN THE H85-H7 MB LAYER BY
MONDAY. LIKE PREVIOUS SHIFT STATED...HIGHER DPTS ADVECTED IN AS
WELL AS SOME SNOW MELT JUICED BL TRAPPED UNDER BUILDING INVERSION TO
INDUCE LLVL STRATUS AND FOG LATE SUNDAY NIGHT INTO MON. STILL SOME
QUESTION ON SPEED OF THIS DEVELOPING/MOISTURE INCREASE AND SOME
RECENT SIGNALS OF THE LOW CLOUDS AND FOG REALLY DEVELOPING MORE
CLOSER TO MONDAY MORNING AS OPPOSED TO SUNDAY NIGHT. BUT WILL KEEP
FOG MENTION SUN NIGHT AND MONDAY. INCREASING LIFT AND MID LEVELS
REMAINING DRY ALOFT SUGGEST DRIZZLE GETTING WRUNG OUT OF THIS LLVL
CLOUD DECK...AND IF SFC TEMPS CAN/T CLIMB ABOVE FREEZING TIL DAWN
MONDAY...MAY BE SOME TROUBLE WITH FREEZING DRIZZLE ALONG AND
NORTH OF I-80 FRO AWHILE AND WILL MENTION IN THE ZONES. LOW CLOUDS
AND LLVL SATURATION MAY LIMIT SFC HEATING ENOUGH TO KEEP TEMPS AT
OR BELOW FREEZING UNTIL MID MON MORNING NORTH OF THE HWY 30 AREAS
AND WILL EXTEND FREEZING DRIZZLE MENTION IN THESE AREAS FOR MON
MORNING. FOG TO CONTINUE WELL INTO MON AS WELL. AS SFC BOUNDARY
SAGS AND STALLS OUT ACRS THE CWA PARALLEL TO MEAN SOUTHWESTERLY
STEERING FLOW ON MON...CONTINUED LLVL MOISTURE TRANSPORT AND
CONVERGENCE INTO THIS FEATURE MAY INCREASE/SATURATE MOISTURE
PROFILES DEEP ENOUGH FOR MORE OF A LIGHT RAIN FORMING ACRS MUCH OF
THE SOUTHEAST TWO THIRDS OF THE DVN CWA BY LATE MORNING AND INTO THE
AFTERNOON. THICK LLVL CLOUDS...FOG...SNOW MELT PROCESS...AND
SATURATION MAY LIMIT SFC HEATING WITH HIGHS MORE IN THE MID TO UPPER
30S IN THE SOUTH HALF AS OPPOSED TO MODEL GUIDANCE UPPER 30S TO LOWER
40S. TEMPS MAY ACTUALLY HAVE TROUBLE WARMING ABOVE 32 IN THE FAR
NORTHERN CWA/NORTH OF CID IA TO FREEPORT IL/ WHICH COULD EXTEND A
FREEZING DRIZZLE OR VERY LIGHT FREEZING RAIN SCENARIO WELL INTO THE
AFTERNOON IN THOSE AREAS. APPROACH OF MAIN UPPER TROF FROM THE
PACIFIC NW AND ACRS THE PLAINS COULD INDUCE SOME LLVL WAVE
DEVELOPMENT ALONG ON THE FRONT WHICH COULD EXTEND SOME PRECIP ALMOST
DEF ZONE STYLE IN THE EASTERN CWA MONDAY EVENING. WITH TOP-DOWN
COOLING AND SATURATION TAKING PLACE...THE RAIN COULD SWITCH OVER TO A
MIX OR ALL SNOW WITHIN A FEW HOURS AFTER SUNSET WITH SOME LIGHT
SLUSHY ACCUMULATION ALONG THE EASTERN I-80 CORRIDOR. TEMPS TO CRASH
LATE MON NIGHT INTO TUE MORNING IN LLVL COLD CONVEYOR WITH VALUES
RANGING FROM THE MID TEENS IN THE NORTHWEST...TO THE MID 20S IN THE
FAR EAST AND SOUTHEAST.
TUESDAY AND WEDNESDAY...THE LLVL CYCLONE REALLY TAKES OFF/DEEPENS
ACRS THE CENTRAL GRT LKS ON TUE...BUT THE BRUNT OF THE PASSING UPPER
TROF ACRS THE LOCAL AREA STILL TO PROBABLY TO MAKE FOR WIDESPREAD
LIGHT SNOWS ACRS MOST OF THE DVN CWA THROUGH LATE TUE AFTERNOON
BEFORE THE UPPER TROF AXIS PASSES ACRS LK MI BY TUE EVENING AND
SUBSIDENCE TAKES OVER IN ITS WAKE. POTENTIAL FOR SOME 1-2 INCH
AMOUNTS BY TUE EVENING MAINLY ALONG AND NORTH OF THE HWY 30
CORRIDOR...BUT MORE OF A STORY WILL BE THE COLD AND NORTHWESTERLY
SFC WINDS GUSTING UP OVER 30 MPH AT TIMES WITH WIND CHILLS NEAR
ZERO IN THE AFTERNOON. CLEARING AND COLD CONDITIONS TUE NIGHT WITH
PASSING LLVL RIDGE LOBE...SOME LOWS BELOW ZERO POSSIBLE IN AREAS
NORTH OF I80. PASSING CLIPPER ACRS MN/WI IN FRESHLY ESTABLISHED BROAD
NORTH-WESTERLIES...MAY USHER YET ANOTHER FRONT INTO THE CWA BY LATE
WED NIGHT WITH POSSIBLE FLURRIES.
THURSDAY THROUGH SATURDAY...LLVL BAROCLINICITY TO GET ALIGNED
PARALLEL UNDER THESE MEAN FLOW NORTH-WESTERLIES ACRS THE CWA ON
THU...AND ANY PASSING WAVE ALOFT IN THE PROGRESSIVE FLOW COULD WRING
OUT SOME LIGHT SNOW OR FLURRIES ALONG THE LLVL THERMAL RIBBON ON THU
AND WILL CARRY LOW CHC POPS FOR THIS POTENTIAL. BOTH THE 12Z RUN
GFS AND ECMWF NOW PICK UP ON A MORE SUBSTANTIAL TYPE CLIPPER-LIKE
WAVE PROPAGATING DOWN IN THIS FLOW ALONG THE BAROCLINICITY WHICH
UTILIZES SOME GULF MOISTURE FEED FROM THE SOUTH TO PRODUCE 1-3 OR
EVEN 2-4 INCHES OF SNOW ACRS THE NORTH HALF OF THE DVN CWA FROM LATE
THU NIGHT INTO FRI MORNING. WILL KEEP CHC POPS GOING FOR SNOW ON FRI
FOR NOW...AND MAYBE A MIX OF RAIN AND SNOW IN THE SOUTH WITH PRE-
SYSTEM WARM DRAW ALOFT POSSIBLE. FLATTENING FLOW AND POST-SYSTEM
RIDGING MAY BRING A LULL IN THE ACTION FOR LATER FRI NIGHT AND SAT.
SOME SIGNS OF ENOUGH WAA ON SAT AHEAD OF TE NEXT DEVELOPING LARGE
SYSTEM TO DRIVE TEMPS INTO THE MID TO UPPER 30S DEPENDING ON SNOW
COVER BY THAT TIME. ..12..
&&
.AVIATION.../ISSUED 1158 AM CST SAT JAN 14 2012/
AN AREA OF LIGHT SNOW OR FLURRIES FROM WESTERN IA INTO EASTERN MN
WILL MOVE EAST ACROSS THIS AFTERNOON AND THIS EVENING. MVFR CIGS/
VSBYS WILL BE ASSOCIATED WITH THE SNOW AT KCID/KDBQ/KMLI LATE THIS
AFTERNOON AND THIS EVENING WITH MAINLY VFR CIGS/VSBYS AT KBRL.
CIGS/VSBYS TO IMPROVE TO VFR BY LATE EVENING OR EARLY SUNDAY MORNING.
LIGHT SOUTHERLY WINDS THIS AFTERNOON THROUGH LATE TONIGHT WILL BE
INCREASING TO AROUND 10KTS SUNDAY MORNING. ..DLF..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
DLF/12
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1145 AM CST SAT JAN 14 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE (TODAY AND SUNDAY)...
09Z WATER VAPOR IMAGERY AND 500 MB RUC ANALYSIS INDICATES A BROAD
UPPER LEVEL TROUGH ROUGHLY OVER THE GREAT LAKES REGION...WITH A
STRONG RIDGE JUST OFF THE SOUTHERN CALIFORNIA COASTLINE. BETWEEN
THOSE TWO FEATURES NORTHWEST FLOW PERSISTS OVER THE CENTRAL
PLAINS. WV IMAGERY INDICATES A VERY SUBTLE SHORTWAVE TROUGH
EMBEDDED WITHIN THE NORTHWEST FLOW MOVING SOUTHEASTWARD. DO NOT
EXPECT TO SEE MANY EFFECTS FROM THIS WAVE SHORT OF SOME PASSING
LOW TO MID CLOUDS EARLY THIS MORNING. BY MID MORNING TO EARLY
AFTERNOON THE WAVE WILL MOVE THROUGH THE AREA AND SUBSIDENCE WILL
TAKE OVER BRINGING MOSTLY CLEAR CONDITIONS. AT THE SURFACE A
FAIRLY STRONG RIDGE HAS SET UP IN THE WESTERN HIGH PLAINS AND HAS
CREATED A DECENT PRESSURE GRADIENT BETWEEN ITSELF AND A WEAK
SURFACE TROUGH WHICH IS CURRENTLY LOCATED IN FAR SE NEBRASKA. AS A
RESULT OF THE GRADIENT BETWEEN THESE TWO FEATURES EXPECT WEST-
NORTHWEST WINDS TO PICK UP IN INTENSITY THROUGHOUT THE DAY
LENDING TO SOME WEAK COLD AIR ADVECTION. HOWEVER WITH LOWS
STARTING OUT A BIT WARMER THAN YESTERDAY AND WITH GOOD INSOLATION
EXPECT TEMPS TO CREEP INTO THE UPPER 40S AND LOWER 50S ACROSS
NORTHEAST KANSAS FOR TODAY. BUMPED MIN TEMPS FOR SUNDAY UPWARD A
LITTLE AS WINDS BACK AROUND TO THE WEST-SOUTHWEST OVERNIGHT AND
PICK UP EARLY SUNDAY MORNING...CREATING SOME WEAK WARM AIR
ADVECTION AND KEEPING TEMPS A BIT WARMER. SUNDAY WILL LIKELY BE
THE NICEST DAY OF THE FORECAST PERIOD...AS STRONG SOUTHERLY WINDS
AND A FLEETING UPPER RIDGE PUSHES THROUGH THE AREA. GIVEN THOSE
TWO FACTORS AS WELL AS GOOD INSOLATION DUE TO CLEAR SKIES EXPECT
TEMPS TO REACH INTO THE LOWER 60S ON SUNDAY.
MID RANGE AND EXTENDED FORECAST (MONDAY THROUGH FRIDAY)...
THE WARM UP WILL NOT LAST LONG AS ANOTHER POTENT COLD FRONT MOVES
INTO NORTHEAST KANSAS MONDAY NIGHT INTO TUESDAY MORNING. AREAS
AHEAD OF THE COLD FRONT...NAMELY SOUTH AND EAST OF THE TURNPIKE
COULD HAVE ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES AS HIGHS
ON MONDAY COULD RISE TO AROUND 60 AGAIN...HOWEVER EXPECT THE COLD
FRONT TO BE SOMEWHERE NEAR THE TURNPIKE BY MID DAY ON MONDAY
MEANING AREAS NORTH AND WEST OF THE TURNPIKE WILL LIKELY ONLY
RISE INTO THE 40S ON MONDAY. A QUICKLY MOVING UPPER WAVE WILL
ALSO PUSH THROUGH THE NORTHERN PLAINS ON MONDAY NIGHT...AND
PERHAPS COULD BRING A PERIOD OF VERY LIGHT SNOW TO AREAS NORTH OF
HIGHWAY 24 ON MONDAY NIGHT. WITH NOT MUCH MOISTURE TO WORK WITH
DO NOT EXPECT MORE THAN A TENTH OR TWO OF SNOW ACCUMULATION FROM
THIS SYSTEM. TUESDAY WILL BE RATHER CHILLY AS THE ARCTIC AIRMASS
TAKES HOLD OF THE AREA...BUT BY WEDNESDAY WEST-SOUTHWEST WINDS
WILL RETURN TO THE AREA BRINGING ANOTHER GENTLE WARM UP. MODELS
THEN HINT AT FRIDAY BEING ANOTHER UNSEASONABLY WARM DAY. SOUTH-
SOUTHWEST WINDS WITH A VERY WARM AIRMASS LOOK TO MAKE THEIR WAY
INTO NORTHEAST KANSAS ON FRIDAY. WILL CURRENTLY STICK WITH TEMPS
IN THE UPPER 40S TO LOWER 50S FOR FRIDAY...BUT IF MODELS CONTINUE
TO TREND TOWARD A WARMER SOLUTION WILL BUMP THOSE TEMPS UP AS
THAT DAY APPROACHES.
JL
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
.AVIATION...
VFR CONDITIONS EXPECTED FOR THE NEXT 24 HRS. WINDS WILL REMAIN
GUSTY UNTIL 20-21Z. WINDS WILL BECOME WESTERLY AND SOUTHWESTERLY
LATER THIS AFTERNOON AND OVERNIGHT AS SURFACE HIGH PRESSURE MOVES
TO THE SOUTHEAST. PRESSURE GRADIENT TIGHTENS AGAIN TOMORROW AND
SOUTHERLY WINDS WILL BECOME GUSTY AFTER 15Z.
ANDERSON
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
210 PM CST SAT JAN 14 2012
.DISCUSSION...
NEED TO DO A QUICK UPDATE FOR TEMPS THIS AFTN AS TEMPS RISING WELL
INTO THE MID 30S IN FAR SE ND... THIS IS HIGHER THAN PREV UDPATE....
&&
.PREV DISCUSSION... /ISSUED 1002 AM CST SAT JAN 14 2012/
DISCUSSION...
MINOR UPDATE TO WINDS AND PRECIP WERE MADE. BASED ON SFC WIND
FIELD WK SFC LOW JUST WEST OF WINNIPEG...WITH WEST WIND SHIFT
THROUGH WALHALLA-CAVALIER THEN TO GRAND FORKS AIR FORCE BASE (AS
OF 1543Z) THEN TO JUST WEST OF FARGO-WAHPETON TO WHEATON. SFC LOW
WILL CONTINUE TO MOVE SLOWLY SOUTHEAST TOWARD BAUDETTE BY 21Z-00Z
AND WITH IT WIND WILL GRADUALLY SHIFT TO THE WEST AS BOUNDARY
MOVES THROUGH. WARMER AIR BEHIND IT WITH TEMPS IN THE MID 20S. FAR
NORTHEAST MAY NEVER QUITE GET INTO THE 20S SO LOWERED A BIT
THERE...OTHERWISE ADJUSTED CURVE A BIT BUT KEPT HIGHS IN THE MID
20S FOR THE MOST PART...WITH SOME READINGS NEAR 30 IN FAR
SOUTHWEST FCST AREA WHERE SOME SUNNY BREAKS WILL OCCUR. OTHERWISE
SATELLITE SHOWS PLENTY OF CLOUDS MOVING SOUTHEAST SO EXPECT
MAJORITY OF THE FCST AREA TO REMAIN IN THE CLOUDS. KEPT FLURRIES
OR LIGHT SNOW IN FOR NORTHEAST 1/2 OF FCST AREA THRU THE DAY AS
UPSTREAM CANADIAN RADAR SHOWS LIGHT ECHOES UP TO DAUPHIN MANITOBA.
,AVIATION...
CIGS WILL REMAIN MOSLY VFR FAR-GFK-DVL THRU THE DAY. TVF-BJI WILL
SEE MVFR CIGS GRADUALLY BECOME VFR IN LIGHT SNOW.
PREV DISCUSSION... /ISSUED 230 AM CST SAT JAN 14 2012/
DISCUSSION...FORECAST CHALLENGE CONCERNS RESIDUAL SNOW CHANCES
TODAY AND TEMPERATURES. MODELS IN GOOD AGREEMENT OVERALL WITH MINOR
DIFFERENCES IN DEGREE OF COLD AIR INTRUSION EARLY NEXT WEEK. WILL
USE BLEND.
BACK EDGE OF SNOW BAND CURRENTLY ALONG A PEMBINA...CARRINGTON AND
WISHEK ND LINE OR ALONG AND EAST OF SURFACE BOUNDARY. BASED ON
CURRENT TIMING BACK EDGE SHOULD BE NEAR A ROX-FAR LINE AT 12Z AND
THIS PRETTY CLOSE TO BOUNDARY LOCATION FROM RUC AND OTHER
OPERATIONAL MODELS. WILL MAKE SOME MINOR POP ORIENTATION ADJUSTMENTS
BUT FORECAST CURRENTLY LOOKING PRETTY WELL. MOST SNOW SHOULD BE
LIMITED TO FAR EASTERN FA THIS AFTERNOON WITH AT MOST FLURRIES
FARTHER WEST. OVERALL STILL LOOKING LIKE A WEAK EVENT WITH MOST
AREAS SEEING LESS THAN AN INCH OF ACCUMULATION. TEMPERATURES HAVE
BEEN SLOWLY RISING AND EXPECT TREND TO CONTINUE. THERMAL ADVECTION
LEVELS OFF AND WESTERN AREAS WILL LIKELY HOLD PRETTY STEADY TODAY.
FARTHER EAST WILL CONTINUE TO SEE SOME RISE AS UPSTREAM DEWPOINTS IN
THE 20S.
TEMPERATURES WILL BE TRICKY AGAIN TONIGHT WITH MINIMUM VALUES LIKELY
MET PRE-MIDNIGHT WITH STEADY OR RISING TEMPERATURES AS MIXING AND
WARM ADVECTION INCREASES LATER TONIGHT. WITH SOME UNCERTAINTY IN
CLOUD TRENDS THIS EVENING WILL HOLD WITH PERSISTENCE.
NEXT SURFACE LOW WITH MID LEVEL WAVE WILL TRACK ALONG CANADIAN/ND/MN
BORDER AREA SUNDAY. ELEVATED COLD ADVECTION WORKS INTO NW QUARTER OF
FA DURING THE AFTERNOON HOWEVER SURFACE WINDS WILL BE WESTERLY ALONG
WITH POTENTIAL FOR SOME SOLAR. WITH LACK OF DEEP SNOW COVER THIS MAY
OVERCOME ANY COLD ADVECTION. FARTHER SOUTH WITH MORE SOLAR AND LESS
COLD ADVECTION MAY HAVE A BETTER CHANCE FOR TEMPERATURES TO EXCEED
32 DEGREES.
STEADY COLD ADVECTION FROM SUNDAY NIGHT THROUGH MONDAY. MODELS NOT
INDICATING ANY PCPN WITH FROPA HOWEVER SOME CLOUD COVER POSSIBLE
BASED ON INTEGRATED RH FIELDS AND A DEGREE OF MIXING MAY KEEP THINGS
FROM GETTING TOO COLD. EVEN WITH CLOUD COVER TEMPERATURES NOT LIKELY
TO RECOVER AT ALL MONDAY AND MAY EVEN DROP.
LONG TERM (TUE-FRI)...
MODELS IN GOOD AGREEMENT FOR THE EXTENDED. NW FLOW ALOFT WITH ARCTIC
AIRMASS SETTLED INTO THE NORTHERN PLAINS AT THE SFC. EXPECT BLO
NORMAL TEMPS AND LITTLE MOISTURE GIVEN THE DRY COLUMN... ONLY LIGHT
SNOW OR FLURRIES FORECAST FOR WEDNESDAY AND THURSDAY AS STORM TRACK
FOR WEAK SFC LOWS WILL BE ALONG BAROCLINIC ZONE SOUTH OF THE FA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
352 PM EST SAT JAN 14 2012
.SYNOPSIS...
A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN
SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS
THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS
ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO
ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS
TO DEVELOP THIS EVENING.
BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE
ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON
QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL
STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND
LESSER AMOUNTS OVER SRN COALFIELDS.
WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW
AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY
WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW
MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH
THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE
ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS
OVER THE MOUNTAINS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
QUIET START TO THE PERIOD WITH HIGH PRESSURE TRUDGING EAST SUNDAY
NIGHT. SOUTHWESTERLY FLOW KICKS IN WITH H925 WINDS INCREASING TO
30-40 KNOTS BY 12Z. THIS FLOW WILL START TO PUSH SOME HIGH CLOUDS
IN TOWARDS MORNING...OTHERWISE SKIES WILL BE MOSTLY CLEAR. THE
WINDS WILL ALSO BE PUSHING IN WARMER AIR ALOFT...H925 TEMPERATURES
RISE FROM -6C AT 00Z TO +6 AT 12Z. MODELS STILL HAVE A SHARP
INVERSION NEAR THE SURFACE THROUGH THE NIGHT. STILL...WITH SUCH
STRONG WINDS ALOFT...THINK SOME OF THE WARMER AIR WILL MIX DOWN AND
ALLOW FOR RISING TEMPERATURES OVERNIGHT. SO...WENT WITH A MIN TEMP
CLOSE TO THE MET AROUND MIDNIGHT...WITH A NONDIURNAL RISE THEREAFTER.
ECMWF DOES LOOK LIKE A GOOD MIDDLE-OF-THE-ROAD APPROACH TO NEXT
SYSTEM...WITH A GENERALLY LARGE MODEL SPREAD. LOW PRESSURE DEVELOPS
IN THE PLAINS ON MONDAY...AND THEN TAKES OFF TO THE NORTHEAST
TOWARDS YYZ BY 00Z WEDNESDAY. SUPPORT WILL BE PROVIDED BY DEEPENING
SHORTWAVE MOVING ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
VALLEY. SOME ISENTROPIC LIFT NOTED ON MONDAY...MUCH OF WHICH WILL GO
INTO MOISTENING THE ATMOSPHERE AT FIRST AND INCREASING CLOUD COVER.
SUFFICIENTLY DEEP MOISTURE ARRIVES BY 18Z AND ALLOWS THE FIRST
RAINDROPS IN SOUTHEAST OHIO. PWAT CONTINUES TO INCREASE IN THE
SOUTHWEST FLOW...EVENTUALLY REACHING AN INCH OR SO BY 12Z TUESDAY.
POPS CONTINUE TO TREND UPWARD...REACHING THEIR PEAK BY 12Z TUESDAY
WITH CATEGORICAL VALUES ACROSS MUCH OF THE AREA. SUPPORT FOR LIFT
WILL BE PROVIDED BY LFQ OF H250 JET ALONG WITH CONTINUED 290/295K
ISENTROPIC UPGLIDE. STILL...RAIN RATES SHOULD NOT BE
EXCESSIVE...AND AROUND A HALF INCH OF RAIN CAN BE EXPECTED FROM THIS
EVENT THROUGH 12Z TUESDAY. RAN CLOSER TO MET NUMBERS MONDAY/MONDAY
NIGHT...WHICH HAD A SMALLER DIURNAL RANGE THAN THE MAV.
THEREAFTER...WE AWAIT COLD FROPA WHICH WILL OCCUR LATER TUESDAY
AFTERNOON AND TUESDAY EVENING. ANOTHER .20 TO .30 INCH OF RAIN IS
POSSIBLE IN CONTINUED MOIST FLOW/LIFT. UNCERTAINTY WITH TIMING LEADS TO
UNCERTAINTY IN CHANGEOVER TO SNOW...BUT FOR NOW THINK THIS OCCURS
AFTER 00Z WEDNESDAY. BY THAT TIME...DEEPER MOISTURE IS DEPARTING
AND ONLY HAVE LIKELY POPS ALONG WESTERN SLOPES...WITH WINDS
BEGINNING THE TRANSITION TO WESTERLY AND EVENTUALLY NORTHWEST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
SURFACE HIGH PRESSURE STARTS THIS PERIOD WITH COLD H85 TEMPS. AS
SYSTEM SWINGS SOUTHEAST ON THURSDAY...COULD SEE SOME LIGHT SNOW
SHOWERS FOR A BRIEF PERIOD OF TIME. AS THIS SYSTEM QUICKLY MOVES
NORTHEAST...ANOTHER IS ON ITS HEELS. BY THE END OF THE WEEK...THIS
SYSTEM SHOULD REACH THE OHIO VALLEY. HOWEVER THIS TIME...WARMER AIR
ACCOMPANIES IT. THIS WOULD LEAD TO RAIN. HPC GUIDANCE HANDLES THIS
WELL. WILL USE HPC WITH SOME MINOR ADJUSTMENTS.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS
ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK
DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF
SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN
FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR
CONDITIONS IN PERIODS OF HEAVIER SNOW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT.
THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST
IN THE WESTERN LOWLANDS.
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 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H M M M M M M M M M M
HTS CONSISTENCY H H H M M M M M M H H H
BKW CONSISTENCY H H H M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY M M L L M M H H H H H H
CKB CONSISTENCY M M M M M M M M M M M M
AFTER 18Z SUNDAY...
IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/JB/CL
NEAR TERM...KMC
SHORT TERM...CL
LONG TERM...JB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
235 PM EST SAT JAN 14 2012
.SYNOPSIS...
A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN
SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS
THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS
ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO
ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS
TO DEVELOP THIS EVENING.
BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE
ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON
QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL
STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND
LESSER AMOUNTS OVER SRN COALFIELDS.
WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW
AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY
WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW
MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH
THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE
ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS
OVER THE MOUNTAINS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
NW UPSLOPE FLOW WILL CONTINUE EARLY IN THE PERIOD BEHIND EXITING
CLIPPER SYSTEM...WITH DRIER AND GRADUALLY WARMER WEATHER TAKING HOLD
FOR THE REMAINDER OF SUNDAY AS SURFACE HIGH PRESSURE AND UPPER
RIDGING TAKE HOLD ACROSS THE CWA OUT AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. WARM FRONT WILL BEGIN TO MOVE NORTH THROUGH THE CWA
BY LATE SUNDAY NIGHT OR EARLY MONDAY. DEPENDING ON TIMING...THIS MAY
MEAN WARMING TEMPERATURES OVERNIGHT SUNDAY NIGHT...BUT FOR
NOW...THINKING TIMING OF WARM FRONT ENTERING CWA WILL BE TOWARDS
MONDAY MORNING...AND THUS...ELECTED TO NOT DO A NON DIURNAL AT THIS
TIME. HOWEVER...PASSAGE OF WARM FRONTAL BOUNDARY/GOOD SOUTHERLY FLOW
DEVELOPING ACROSS THE CWA WILL ALLOW FOR NICE WARM TEMPERATURES ON
MONDAY...WITH MANY LOCATIONS WARMING INTO THE 40S TO 50S.
LOW PRESSURE TO THE WEST WILL CONTINUE TO APPROACH THE AREA ON
MONDAY...WITH MOISTURE SPREADING INTO THE AREA MONDAY EVENING. THIS
LOOKS TO BE A MOIST SYSTEM...AS STRONG LLJ...WITH A GOOD MOISTURE
TAP INTO THE GULF OF MEXICO...WILL RAISE PW VALUES TO BETWEEN 0.8 TO
1 INCH. THIS IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS
TIME OF YEAR. EXPECTING DECENT RAINFALL AMOUNTS WITH THIS SYSTEM DUE
TO EXPECTED MOISTURE...AS WELL AS THE FACT THAT THERE IS THE
POTENTIAL FOR SEVERAL WAVES EMBEDDED IN THE FLOW TO ENHANCE RAINFALL
AMOUNTS AT TIMES. FOR NOW...GENERALLY HAVE BETWEEN 0.6 TO 0.8 INCHES
OF RAIN FORECAST FOR THIS PERIOD. PROGRESSIVE NATURE SHOULD HELP
LIMIT EXCESSIVE RAINFALL. WITH GOOD WAA OUT AHEAD OF
SYSTEM...EXPECTING PRECIPITATION TO START OUT AS RAIN PRETTY MUCH
EVERYWHERE. EXCEPTION WOULD BE OVER SHELTERED VALLEYS OF POCAHONTAS
COUNTY...WHERE MODEL SOUNDINGS INDICATE POTENTIAL FOR VERY BRIEF
FZRA MONDAY NIGHT.
IN ADDITION TO RAIN...STRONG WINDS ALOFT ALONG WITH A DEVELOPING
TIGHT PRESSURE GRADIENT WILL CREATE RATHER GUSTY WINDS AT
TIMES...AND INCREASED FORECAST WINDS FROM PREVIOUS FORECAST AS A
RESULT.
COLD FRONT ASSOCIATED WITH THE LOW WILL SWEEP THROUGH THE AREA
TUESDAY NIGHT...WITH MUCH COLDER AIR FILTERING IN BEHIND THE FRONT.
THIS WILL RESULT IN A GRADUAL CHANGE OVER TO SNOW ACROSS THE CWA. AT
THIS POINT...ACCUMULATIONS APPEAR TO BE SOMEWHAT LIMITED AS
ATMOSPHERE SHOULD QUICKLY DRY OUT...AS IS OFTEN THE CASE. ALSO...AT
THIS POINT...DOESNT APPEAR AS THOUGH WE WILL HAVE A PROLONGED
UPSLOPE SNOW SHOWER EVENT BEHIND THE COLD FRONT...WHICH WILL ALSO
HELP TO LIMIT ACCUMULATIONS SOMEWHAT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SURFACE HIGH PRESSURE STARTS THIS PERIOD WITH COLD H85 TEMPS. AS
SYSTEM SWINGS SOUTHEAST ON THURSDAY...COULD SEE SOME LIGHT SNOW
SHOWERS FOR A BRIEF PERIOD OF TIME. AS THIS SYSTEM QUICKLY MOVES
NORTHEAST...ANOTHER IS ON ITS HEELS. BY THE END OF THE WEEK...THIS
SYSTEM SHOULD REACH THE OHIO VALLEY. HOWEVER THIS TIME...WARMER AIR
ACCOMPANIES IT. THIS WOULD LEAD TO RAIN. HPC GUIDANCE HANDLES THIS
WELL. WILL USE HPC WITH SOME MINOR ADJUSTMENTS.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS
ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK
DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF
SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN
FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR
CONDITIONS IN PERIODS OF HEAVIER SNOW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT.
THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST
IN THE WESTERN LOWLANDS.
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 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H M M M M M M M M M M
HTS CONSISTENCY H H H M M M M M M H H H
BKW CONSISTENCY H H H M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY M M L L M M H H H H H H
CKB CONSISTENCY M M M M M M M M M M M M
AFTER 18Z SUNDAY...
IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/JB/CL
NEAR TERM...KMC
SHORT TERM...SL
LONG TERM...JB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
217 PM EST SAT JAN 14 2012
.SYNOPSIS...
A CLIPPER PASSES SOUTH TONIGHT. WARM UP EARLY NEXT WEEK. RAIN
SYSTEM MONDAY NIGHT AND TUESDAY. COLDER WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK S/W EMBEDDED AN CHANNELED WESTERLY FLOW WILL TRAVERSE ACROSS
THE SOUTHERN COALFIELDS AND SOUTHWESTERN VA THIS EVENING. DYNAMICS
ASSOCIATED WITH THIS FEATURE QUITE MODEST...AND MOISTURE IS NOT TOO
ROBUST. CONDITIONS ARE FAVORABLE FOR A SHORT PERIOD SNOW SHOWERS
TO DEVELOP THIS EVENING.
BOTH NAM AND GFS IN PRETTY CLOSE AGREEMENT IN TIMING THE FEATURE
ACROSS FOR FORECAST AREA. BOTH MODELS HAVE BACKED OFF SLIGHTLY ON
QPF AMOUNTS FROM PREVIOUS RUNS. HOWEVER...SHORT TERM HRRR MODEL
STILL PAINTS SOME QPF IN THE FORM OF LIGHT SNOW OVER SW VA...AND
LESSER AMOUNTS OVER SRN COALFIELDS.
WILL CONTINUE WITH WSW FOR SW VA...KEEPING THE SAME GENERAL SNOW
AMOUNTS IN PLACE. HOWEVER...SINCE MODELS HAVE BACKED OFF SLIGHTLY
WITH AMOUNT OF MOISTURE AND UPSTREAM OBS AND SAT IMAGERY DO NOT SHOW
MUCH HAPPENING WITH THIS SHORTWAVE...HAVE BACKED OFF SLIGHTLY WITH
THE AREA COVERAGE OF SNOW ACCUMULATIONS FOR AREAS OUTSIDE THE
ADVISORY. USED ADJMETBC FOR PRIMARY TEMP FIELDS...WITH ADJUSTMENTS
OVER THE MOUNTAINS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
NW UPSLOPE FLOW WILL CONTINUE EARLY IN THE PERIOD BEHIND EXITING
CLIPPER SYSTEM...WITH DRIER AND GRADUALLY WARMER WEATHER TAKING HOLD
FOR THE REMAINDER OF SUNDAY AS SURFACE HIGH PRESSURE AND UPPER
RIDGING TAKE HOLD ACROSS THE CWA OUT AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. WARM FRONT WILL BEGIN TO MOVE NORTH THROUGH THE CWA
BY LATE SUNDAY NIGHT OR EARLY MONDAY. DEPENDING ON TIMING...THIS MAY
MEAN WARMING TEMPERATURES OVERNIGHT SUNDAY NIGHT...BUT FOR
NOW...THINKING TIMING OF WARM FRONT ENTERING CWA WILL BE TOWARDS
MONDAY MORNING...AND THUS...ELECTED TO NOT DO A NON DIURNAL AT THIS
TIME. HOWEVER...PASSAGE OF WARM FRONTAL BOUNDARY/GOOD SOUTHERLY FLOW
DEVELOPING ACROSS THE CWA WILL ALLOW FOR NICE WARM TEMPERATURES ON
MONDAY...WITH MANY LOCATIONS WARMING INTO THE 40S TO 50S.
LOW PRESSURE TO THE WEST WILL CONTINUE TO APPROACH THE AREA ON
MONDAY...WITH MOISTURE SPREADING INTO THE AREA MONDAY EVENING. THIS
LOOKS TO BE A MOIST SYSTEM...AS STRONG LLJ...WITH A GOOD MOISTURE
TAP INTO THE GULF OF MEXICO...WILL RAISE PW VALUES TO BETWEEN 0.8 TO
1 INCH. THIS IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS
TIME OF YEAR. EXPECTING DECENT RAINFALL AMOUNTS WITH THIS SYSTEM DUE
TO EXPECTED MOISTURE...AS WELL AS THE FACT THAT THERE IS THE
POTENTIAL FOR SEVERAL WAVES EMBEDDED IN THE FLOW TO ENHANCE RAINFALL
AMOUNTS AT TIMES. FOR NOW...GENERALLY HAVE BETWEEN 0.6 TO 0.8 INCHES
OF RAIN FORECAST FOR THIS PERIOD. PROGRESSIVE NATURE SHOULD HELP
LIMIT EXCESSIVE RAINFALL. WITH GOOD WAA OUT AHEAD OF
SYSTEM...EXPECTING PRECIPITATION TO START OUT AS RAIN PRETTY MUCH
EVERYWHERE. EXCEPTION WOULD BE OVER SHELTERED VALLEYS OF POCAHONTAS
COUNTY...WHERE MODEL SOUNDINGS INDICATE POTENTIAL FOR VERY BRIEF
FZRA MONDAY NIGHT.
IN ADDITION TO RAIN...STRONG WINDS ALOFT ALONG WITH A DEVELOPING
TIGHT PRESSURE GRADIENT WILL CREATE RATHER GUSTY WINDS AT
TIMES...AND INCREASED FORECAST WINDS FROM PREVIOUS FORECAST AS A
RESULT.
COLD FRONT ASSOCIATED WITH THE LOW WILL SWEEP THROUGH THE AREA
TUESDAY NIGHT...WITH MUCH COLDER AIR FILTERING IN BEHIND THE FRONT.
THIS WILL RESULT IN A GRADUAL CHANGE OVER TO SNOW ACROSS THE CWA. AT
THIS POINT...ACCUMULATIONS APPEAR TO BE SOMEWHAT LIMITED AS
ATMOSPHERE SHOULD QUICKLY DRY OUT...AS IS OFTEN THE CASE. ALSO...AT
THIS POINT...DOESNT APPEAR AS THOUGH WE WILL HAVE A PROLONGED
UPSLOPE SNOW SHOWER EVENT BEHIND THE COLD FRONT...WHICH WILL ALSO
HELP TO LIMIT ACCUMULATIONS SOMEWHAT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
GENERALLY USED ECMWF MEAN FOR THE PERIOD. A RAIN SYSTEM MOVES INTO
THE REGION MONDAY NIGHT AND TUESDAY...FOLLOWED BY ANOTHER COLD SNAP
TUESDAY NIGHT AND WEDNESDAY. COULD SEE SOME UPSLOPE SNOW
ACCUMULATIONS TUESDAY NIGHT AND WEDNESDAY WITH THE COLD AIR.
FORECAST GETS MUCH LOWER CONFIDENCE FOR THE END OF THE WORK WEEK AS
OPERATIONAL MODELS DIVERGE CONSIDERABLY.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
SEEING SLOW RECOVERY TO MVFR AND VFR CONDITIONS THIS AFTERNOON AS
ATMOSPHERIC COLUMN GOES THROUGH SOME MODEST DRYING. WEAK
DISTURBANCE PASSES TO OUR SOUTH THIS EVENING KICKING OFF ROUND OF
SNOW SHOWERS. BROUGHT IN A SHORT PERIOD OF MVFR CONDITIONS IN -SN
FOR KBKW. AREAS TO THE SOUTH AND WEST OF KBKW WILL LIKELY SEE IFR
CONDITIONS IN PERIODS OF HEAVIER SNOW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CEILING HEIGHTS DURING THE DAY SAT DIFFICULT.
THE +-3 THSD FT CEILINGS MAY BECOME SCATTERED QUICKER THAN FORECAST
IN THE WESTERN LOWLANDS.
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 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H M M M M M M M M M M
HTS CONSISTENCY H H H M M M M M M H H H
BKW CONSISTENCY H H H M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY M M L L M M H H H H H H
CKB CONSISTENCY M M M M M M M M M M M M
AFTER 18Z SUNDAY...
IFR POSSIBLE IN SNOW SHOWERS TUESDAY NIGHT AND WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/JB/CL
NEAR TERM...KMC
SHORT TERM...SL
LONG TERM...RPY
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
320 PM EST SAT JAN 14 2012
.SYNOPSIS...
A CLIPPER AREA OF LOW PRESSURE ARRIVES FROM THE NORTHWEST TONIGHT
INTO EARLY SUNDAY...BRINGING ANOTHER ROUND OF MOUNTAIN SNOW
SHOWERS. HIGH PRESSURE WILL BUILD ACROSS THE AREA SUNDAY AND
OFFSHORE INTO MONDAY PROVIDING A GRADUAL MODERATION IN
TEMPERATURES FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 230 PM EST SATURDAY...
ISSUED A WSW FOR SOUTHWEST PORTIONS OF CWA TONIGHT INTO SUNDAY
MORNING FOR LIGHT SNOW EVENT ASSOCIATED WITH A FAST MOVING CLIPPER.
LEANING TOWARDS BLEND OF THE SREF AND NAM BELIEVE THERE IS ENOUGH
LOW LEVEL MOISTURE WITH SHORTWAVE TO PRODUCE 1 TO 3 INCHES OF SNOW
ACROSS THE HIGHER TERRAIN WITH A BURST OF SNOW ALONG THE WESTERN
SLOPES...ESPECIALLY IN THE NW NC MOUNTAINS WHERE UVV IS FORECAST TO
BE THE GREATEST. WITH LOCAL WRFARW-RNK AND HRRR EVEN SHOWING
MOISTURE SPREADING FURTHER EAST...DECIDED TO EXPAND AND INCREASE
CHANCES INTO THE MOUNTAINS AND ALLOW FOR SNOW FLURRIES TO SPILL EAST
INTO THE FOOTHILLS. PLAYED LOW TEMPERATURES TONIGHT CLOSE TO THE
ADJMAV WITH READINGS FROM AROUND 10 DEGREES WITH SNOWPACK IN THE
NORTHWEST MOUNTAINS TO THE MID 20S IN THE SOUTHEAST. SNOW SHOWERS
AND SNOW FLURRIES WILL END QUICKLY SUNDAY...WITH UPPER RIDGE AND SFC
HIGH BUILDING OVER THE REGION. WENT WITH HIGHS ON SUNDAY FROM THE
MID 20S IN THE NORTHWEST TO THE LOWER 40S IN THE SOUTHEAST.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 300 PM EST SATURDAY...
CHALLENGING PORTION OF THE FORECAST. HIGH PRESSURE ALTHOUGH LEAVING
SE WEST VA LATE SUNDAY NIGHT...SHOULD ALLOW DECOUPLING AND TEMPS TO
FALL NEAR DEWPOINT LEVELS. THIS WOULD PUT MOST SPOTS AT OR BELOW
GUIDANCE...ESPECIALLY THE SOUTHSIDE AND PIEDMONT WHERE HIGH PRESSURE
IS CENTERED AT 1Z/7A MONDAY. LAST FRAME OF RGEM SIMULATED SAT IMAGES
SHOWS AT LEAST THICK HIGH CLOUDS JUST THEN ENTERING THE SW QUARTER
OF OUR CWA ALSO AT THAT TIME...WITH A LATE SSW TO SW WIND DEVELOPING
LATE SUNDAY NIGHT. THUS...TEMPS MAY RISE LATE SUNDAY NIGHT ACROSS NW
NC AND EXTREME SW VA AFTER DECOUPLING EARLIER IN THE EVENING...BUT
WILL NOT TRY TO PUT THIS DETAIL IN THE HOURLY T GRIDS FOR NOW. WITH
THE CLOUDS THICKENING IN THE WEST MONDAY MORNING...AND THEN MOVING
EAST BY LATE DAY...TEMPS MAY HAVE A HARD TIME WARMING TO GUIDANCE
NUMBERS WITH MOSTLY CLOUDY SKIES AND A STEEP INVERSION IN PLACE WITH
H85 TEMPS UNLIKELY TO MIX TO THE SURFACE. CONSIDERING THIS
REGIME...MONDAY NIGHT`S FORECAST BECOMES ALL THE MORE
DIFFICULT...WITH TEMPS WARM ENOUGH ALOFT FOR RAIN...BUT RATHER LARGE
DEWPOINT DEPRESSION AND POSSIBLY SOME BROKEN CLOUD COVER...TEMPS
COULD FALL FAST IN THE SHELTERED VALLEYS WEST OF THE BLUE
RIDGE...FOR SOME POSSIBLE FREEZING RAIN...BEFORE TEMPS WARM AFTER
MIDNIGHT TO ABV FREEZING. DID HAVE TO PUT IN HOURLY T GRIDS FOR THIS
PERIOD...AS LESS CLOUDS IN THE EXTREME EAST MAY ALLOW THOSE PARTS TO
DECOUPLE AGAIN...WHEREAS TEMPS FALL INITIALLY IN SE WEST VA THEN
RISE SLIGHTLY AFTER MIDNIGHT. GROUND ALSO WILL BE RATHER COOL
CONSIDERING FEW DAY STRING OF MORE WINTERLIKE TEMPS INCLUDING LOWS IN
THE MID AND UPPER TEENS SUNDAY NIGHT. FOR NOW...COMBINED A SLT CHC
OF FREEZING RAIN FOR A FEW HOURS WITH REGULAR RAIN TO HIGHLIGHT THIS
THREAT. H85 TEMPS THEN AT 12Z/7A TUESDAY SITTING AROUND +6C SHOULD
EVEN WITH THE RAIN AROUND ALLOW TEMPS TO PUSH 60F EAST OF THE BLUE
RIDGE AND MAYBE EVEN ROANOKE TOO...WITH A DOWNSLOPING WIND AND WARM
SURGE AHEAD OF THE NEXT POTENT BAROCLINIC BOUNDARY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM EST SATURDAY...
A COLD FRONT WILL ROLL ACROSS THE REGION TUESDAY EVENING WITH RAIN
SHOWERS ENDING AROUND MIDNIGHT. VERY COLD AIR AND A TIGHT PRESSURE
GRADIENT WILL THEN BRING WINDY AND GUSTY CONDITIONS TO THE
AREA...ALONG WITH WESTERN UPSLOPE SNOW SHOWERS INTO WEDNESDAY
MORNING. THE WIND AND SNOW WILL BE BRIEF AS HIGH PRESSURE BUILDS
INTO THE REGION WEDNESDAY AFTERNOON. HIGH PRESSURE DRIFTS OFF THE
EAST COAST...WHILE A DISTURBANCE TRACKS OVER THE NORTHERN OHIO
VALLEY THURSDAY. THIS DISTURBANCE IS FAR ENOUGH AWAY FROM THE AREA
TO KEEP POPS LOW AND CONFIDED TO THE GREENBRIER VALLEY/ALLEGHANY
HIGHLANDS THURSDAY EVENING. ANOTHER DISTURBANCE IS EXPECTED TO TRACK
ACROSS THE OHIO VALLEY FRIDAY NIGHT AND SATURDAY. THIS DISTURBANCE
HAS PACIFIC ORIGIN AND WILL BE WARM WHEN IT ENTERS THE REGION.
COLD TEMPERATURES WILL HANG AROUND TUESDAY NIGHT INTO WEDNESDAY
NIGHT. AS THE CHILLY HIGH PRESSURE SYSTEM MOVES OFF THE COAST AND
ZONAL FLOW IS ESTABLISHED ON THURSDAY...TEMPERATURES WILL MODERATE
ABOVE NORMAL FRIDAY AND SATURDAY.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
AS OF 1134 AM EST SATURDAY...
SCT TO BKN MVFR CLOUDS IN THE WESTERN MOUNTAINS THIS AFTERNOON.
OTHERWISE...VFR CONDITION EXPECTED. GUSTY NORTHWEST WINDS ACROSS
THE HIGHER TERRAIN MAY HINDER AVIATION OPERATIONS.
A LAYER OF CLOUDS AROUND 5K FEET WILL SPREAD EAST ACROSS CWA
LATE THIS AFTERNOON AND EARLY THIS EVENING AT ALL TAF SITES.
A UPPER LEVEL DISTURBANCE WILL MOVE THROUGH OUR AREA TONIGHT
BRINGING A REINFORCEMENT OF COLD AIR AND SNOW SHOWERS TO KBLF AND
KLWB. SNOW OR SNOW FLURRIES MAY EVEN PUSH INTO KBCB/KROA LATE
TONIGHT INTO SUNDAY MORNING. MVFR CIGS WILL RETURN FOR KBLF AND
KLWB INTO SUNDAY.
SHOULD SEE ALL SITES RETURN TO VFR UNDER HIGH PRESSURE ON MONDAY
WITH ANOTHER FRONT BRINGING ADDED CHANCES OF RAIN AND LOW CIGS BY
TUESDAY. WITH COLDER AIR COMING IN WEDNESDAY...MOUNTAINS SNOW
SHOWERS AND SNOW FLURRIES ARE POSSIBLE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 9 AM EST SUNDAY FOR VAZ007-009-
015.
NC...WINTER WEATHER ADVISORY UNTIL 9 AM EST SUNDAY FOR NCZ001-018.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...KK/PH
SHORT TERM...KM
LONG TERM...RCS
AVIATION...KK/PH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
246 PM CST SAT JAN 14 2012
.SHORT TERM...TONIGHT AND SUNDAY.
THE SURFACE PRESSURE PATTERN OVER THE REGION WAS CAUSING SOME
ISSUES IN THE SHORT TERM. 20Z ANALYSIS SHOWED WEAK LOW PRESSURE
OVER LAKE MICHIGAN...A WEAK RIDGE OVER WISCONSIN AND A TROUGH
ACROSS MINNESOTA.
CONVERGENCE OVER THE LAKE RESULTED IN A BAND OF LAKE EFFECT SNOW
SHOWERS THAT PUSHED WEST INTO DOOR COUNTY. THE 15Z RUC APPEARED TO
HAVE A DECENT HANDLE ON THE SITUATION AS IT WAS SHOWING QPF IN THE
EASTERN PART OF THE FORECAST AREA INTO THIS EVENING. WENT WITH
SOME POPS IN THE EAST FOR THE EVENING BUT DRY THERE AFTER 06Z.
NOT REALLY SURE WHAT WAS CAUSING THE LIGHT SNOW AND FLURRIES IN
CENTRAL WISCONSIN TODAY DIRECTLY UNDER THE SURFACE RIDGE...POSSIBLY
SOME WEAK SHORT WAVE ENERGY PASSING THROUGH THE STATE. THE
VISIBILITY IN SOME LOCATIONS WENT AS LOW AS 3 MILES WITH SNOW AT
TIMES.
ANOTHER AREA OF LIGHT SNOW...WITH VISIBILITIES BELOW 2 MILES...WAS
ASSOCIATED WITH A WARM FRONT ACROSS MINNESOTA...AND A SHEARED UPPER
LEVEL SHORT WAVE. MODELS HAD THE FRONT DECAYING...THE SHORT WAVE
ENERGY MOVING SOUTHEAST THIS EVENING AND HAD QPF DRYING UP BEFORE
REACHING THE FORECAST AREA. HAVE SOME SLIGHT CHANCE POPS FOR
CENTRAL WISCONSIN DURING THE EVENING...BUT NOTHING AFTER 06Z.
TIME/HEIGHT SECTIONS FROM MODELS HAD QUITE A BIT OF LOW LEVEL
MOISTURE WITH LITTLE LIFT LATE TONIGHT...MAINLY IN THE NORTH. SO
HAVE INCLUDED A SLIGHT CHANCE OF FREEZING DRIZZLE OR FLURRIES
THERE 06Z-12Z SUNDAY.
PLENTY OF CLOUDS TONIGHT...BUT THINK THAT TEMPERATURES SHOULD FALL
INTO THE SINGLE DIGITS IN MOST LOCATIONS. WARMER THAN NORMAL HIGHS
RETURN ON SUNDAY IN STRONG WARM ADVECTION AHEAD OF THE SURFACE
SYSTEM APPROACHING FROM THE WEST. MODELS STILL HAD PLENTY OF
CLOUDS SO DID NOT GO TOO MUCH ABOVE GUIDANCE HIGHS.
EXPECT WINDS TO STEADILY INCREASE DURING THE DAY ON SUNDAY AHEAD
OF THE APPROACHING SYSTEM.
.LONG TERM...MONDAY THROUGH NEXT SATURDAY.
NOT MUCH CHANGE TO THE IDEA OF DEVELOPMENT OF HIGH AMPLITUDE
RIDGING OVER THE BERING STRAIT WITH NRN STREAM ENERGY DIGGING SE
THRU ALASKA/WRN CANADA. THIS RESULTS IN DEVELOPING BROAD UPPER
TROF ACROSS SRN CANADA/NRN CONUS. THE MEAN FLOW UNDER THIS TROF TO
BE NEAR ZONAL FROM THE US...BRINGING SEVERAL RELATIVELY WEAK
SYSTEMS ACROSS THE WRN GREAT LAKES.
AT BEGINNING OF PERIOD...LOW PRESSURE MOVES EAST INTO CNTRL
ONTARIO SUNDAY NGT AND DRAGS COLD FRONT INTO CNTRL WI BY 12Z MONDAY. IT
STILL APPEARS THAT GULF MOISTURE WILL NOT HAVE TIME TO REACH THE
FORECAST AREA PRIOR TO THE FRONTAL PASSAGE. FRONT EXISTS REGION BY
EARLY IN THE AFTERNOON...THEN SHORT WAVE TROF APPROACHES FROM THE W.
SNOW SHOULD DEVELOP ALONG TIGHT BAROCLINIC ZONE ACROSS THE AREA BY
EARLY TUESDAY. ALL MODELS IN GENERAL AGREEMENT WITH DEVELOPMENT OF SFC
WAVE ALONG THE FRONT. ACCUMULATIONS SHOULD BE GENERALLY
MINOR...LESS THAN 2 INCHES THRU TUE. SOME LAKE EFFECT LINGERS IN
LAKE SUPERIOR SNOW BELT OF FORECAST AREA INTO TUE NIGHT. MIDWEEK
TEMPS WILL BE BELOW NORM AS ARCTIC AIR BRIEFLY FINDS A HOME.
SMALL CHANCES FOR SNOW SHOWERS ACROSS AREA AS WEAK RIPPLES IN WNW
UPPER FLOW CONTINUE TO MOVE ALONG BAROCLINIC ZONE. BOTH THE 14/12Z
GFS AND ECMWF TARGET FRIDAY AS THE BEST SNOW CHANCE IN THE SECOND
HALF OF THE WEEK WITH SHORT WAVE TROF MOVING ACROSS MIDWEST AND
SURFACE LOW MOVING ACROSS S ILLINOIS.
&&
.AVIATION...QUITE A BIT OF UNCERTAINTY EXISTS DURING THE TAF
PERIOD. CURRENT TRENDS WERE CHALLENGING ENOUGH. CIGS WERE MAINLY
MVFR NORTH AND WEST OF THE FOX VALLEY AND VFR OVER THE REST OF THE
AREA. THERE WERE ALSO SCATTERED MVFR VSBYS IN LIGHT SNOW AND/OR
HAZE. A LAKE EFFECT BAND OVER LAKE MICHIGAN WAS DRIFTING TOWARD
WISCONSIN AS A TROUGH/FRONT APPROACHED THE STATE FROM THE WEST.
THINK THERE WILL BE SOME LIGHT SNOW OR FLURRIES GOING ON MUCH OF
THE NIGHT WITH MOSTLY MVFR CIGS AS THE SURFACE BOUNDARY APPROACHES
FROM THE WEST. TIME/HEIGHT SECTIONS INDICATED A DECREASE IN LOW
LEVEL MOISTURE AFTER ABOUT 15Z SUNDAY WITH SOME MID CLOUDS ABOVE
THAT. PAY EXTRA ATTENTION TO CURRENT CONDITIONS AND WATCH FOR TAF
UPDATES IF YOU PLAN TO FLY IN THE AREA THIS AFTERNOON THROUGH
SUNDAY MORNING.
MG
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MG/JKL
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1205 PM CST SAT JAN 14 2012
.UPDATE...FLURRIES OVER THE EASTERN CWA DIMINISHING AS DRIER MID
LEVEL AIR ADVECTS IN. CLOUD COVER THINNER AND MORE SCATTERED THAN
PREVIOUSLY EXPECTED...BUT ENOUGH SNOW COVER IS PRESENT THAT
SUNSHINE HAS NOT HAD A BIG IMPACT ON TEMPS. BUMPED HIGHS DOWN
SLIGHTLY. BIGGEST CHANGE TO AFTERNOON PERIOD WILL BE POPS.
ISENTROPIC ANALYSIS NO LONGER SHOWS NECESSARY INGREDIENTS FOR
PRECIP FORMATION. THIS IS BACKED UP BY LATEST 3KM HRRR OUTPUT.
WILL BACK OFF TO SLIGHT CHANCE...KEEPING IT IN THE WEST.
&&
.AVIATION/18Z TAFS/...FLURRIES STILL LINGERING FROM MADISON AND
EASTWARD. SHOULD SEE FLURRIES DIMINISH THROUGH THE AFTERNOON AS
THE LOW LEVELS DRY OUT. SKIES ARE MAINLY VFR NOW ACROSS SRN
WI...BUT COULD STILL SEE A FEW SPOTS OF BRIEF MVFR CIGS AS THINGS
SLOWLY DRY OUT.
WEAK WAVE TO SLIDE THROUGH THIS EVENING...BUT LOOKING EVEN WEAKER
AND DRIER WITH LATEST MODELS. THOUGH FLURRIES MAY BE POSSIBLE FROM
AROUND MADISON AND SOUTHWEST...CHANCES LOOK LOW ENOUGH TO REMOVE
FROM MSN TAFS. MODELS SATURATE THE LOW LEVELS FOR A TIME BEHIND
THE WAVE LATE TONIGHT INTO SUNDAY MORNING...SO PUT SOME MVFR CIGS
IN THE TAFS.
&&
.PREV DISCUSSION... /ISSUED 341 AM CST SAT JAN 14 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
BACK EDGE OF LOW CLOUDS HAVE BEEN MOVING STEADILY EWD AT 12KTS SINCE
FRI EVE...HOWEVER HAVE NOTICED SLIGHT SLOWING OF PROGRESSION EWD
SINCE 07Z. LOW LEVEL CYCLONIC CURVATURE AND BULK OF CLOUDS IN
DENDRITIC GROWTH ZONE BELOW INVERSION WL CONTINUE TO SHAKE OUT SOME
FLURRIES THIS MRNG...ESPECIALLY IN THE SOUTHEAST. SLIGHTLY DRIER
AIR SETTLING IN FROM THE NORTHEAST WL HELP TO END THE FLURRIES MOST
AREAS.
LOW LEVEL THERMAL TROUGH LINGERS ACROSS EASTERN WI THRU MID-AFTN...
SO EXPC LOW CLOUDS TO HANG ON INTO THE AFTN. UPSTREAM SHORT WAVE
AND ASSOCIATED SWIRL SHOWS UP CLEARLY ON WATER VAPOR IMAGERY OVR ERN
SASK PUSHING INTO SW MANITOBA. SHORT TERM GUIDANCE IN GOOD
AGREEMENT ON CARRYING THIS WAVE SOUTHEAST AND ACROSS SW WI THIS
EVE. EXPC WAVE TO WEAKEN AS IT MOVES ACROSS OUR REGION DUE TO
UPSTREAM SUBSIDENCE SPREADING RAPIDLY EWD INTO THE NRN PLAINS AND
UPPER MIDWEST...AHEAD OF NEXT STRONGER WAVE PUSHING THRU SW CANADA.
CONDENSATION PRESSURE DEFICITS ON 280 THETA SFC LOWER TO LESS THAN
10MB WITH WEAK ISENTROPIC UPGLIDE BY LATE AFTN OVER WRN CWA.
WL INCREASE TO LKLY WORDING IN FAR WEST BY LATE AFTN. AREA OF LOWER
CPD AFFECTS REST OF SOUTH CENTRAL WI THRU THE EARLY EVE...HOWEVER
WEAK FORCING CONTINUES TO DIMINISH. THINK THERE WILL BE AREAS OF
VERY LIGHT SNOW AROUND SOUTH CENTRAL...AND PARTS OF SOUTHEAST IN THE
EVE...BUT MANY LOCATIONS WL NOT RECEIVE MEASURABLE QPF. HENCE WL
KEEP POPS ON THE LOW SIDE...AND NEXT SHIFT WL BE ABLE TO TWEAK.
WHILE WEAK FORCING LINGERS OVER SOUTH CENTRAL WI DURING THE LATE
EVENING...MID LEVELS DRY OUT. HENCE VERY SMALL THREAT OF PATCHY
FREEZING DRIZZLE FOR A FEW HOURS. CLOUDS EXPCD TO HANG ON THRU LATE
TNGT IN WEAK FLOW.
SHORT TERM...SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM.
WARM AIR ADVECTION CONTINUES ON SUNDAY ACROSS THE AREA. SURFACE
PRESSURE GRADIENT TIGHTENS ACROSS THE AREA...WHICH SHOULD ALLOW
FOR BREEZY SOUTH SOUTHEAST WINDS. SKIES SHOULD GRADUALLY SCATTER
OUT AS THE DAY GOES ON...WHICH SHOULD ALLOW TEMPERATURES TO RISE
INTO THE LOWER TO PERHAPS MID 30S.
AREA REMAINS IN WARM SECTOR SUNDAY NIGHT...AS COLD FRONT
APPROACHES FROM THE NORTHWEST. NAM CONTINUES TO BE ONLY SHORT TERM
MODEL TO PRODUCE VERY LIGHT QPF WITH THE FRONT SUNDAY NIGHT. AREA
FORECAST SOUNDINGS FROM NAM ARE QUITE DRY EXCEPT THE BOUNDARY
LAYER DURING THIS TIME...WITH THE GFS SIMILAR. THUS...WILL
CONTINUE DRY FORECAST SUNDAY NIGHT. TEMPERATURES WILL REMAIN MILD
WITH SOUTH WINDS AHEAD OF THE FRONT.
COLD FRONT SLIDES SOUTHEAST THROUGH THE FORECAST AREA ON MONDAY.
NAM CONTINUES TO SHOW VERY LIGHT QPF IN THE MORNING...WITH THE
OTHER SHORT TERM MODELS DRY IN THE MORNING. NAM/CANADIAN/ECMWF
THEN SHOW LIGHT QPF IN THE FAR SOUTHEAST COUNTIES MONDAY
AFTERNOON...WITH THIS AREA ON NORTHERN PERIPHERY OF LOW LEVEL
FRONTOGENESIS BAND. AREA FORECAST SOUNDINGS FROM NAM/GFS SHOWING
AIR COLUMN HAVING A TOUGH TIME SATURATING...MAINLY IN THE 850MB TO
500MB LAYER. FOR NOW...WILL MAINTAIN CHANCE POPS FOR MONDAY.
TEMPERATURES WOULD SUPPORT LIGHT SNOW IN THE MORNING...AND A MIX
IN THE AFTERNOON IN THE SOUTHEAST AS TEMPERATURES WARM.
NAM/GFS/CANADIAN MODELS ARE TAKING SURFACE LOW FROM CENTRAL/WEST
CENTRAL MISSOURI TO SOUTHEAST LOWER MICHIGAN/NORTHWEST OHIO MONDAY
NIGHT...WITH THE ECMWF SLOWER AND ONLY IN NORTHERN INDIANA BY 12Z
TUESDAY. 850MB BAROCLINIC ZONE AND LOW LEVEL FRONTOGENESIS
RESPONSE SHIFT SOUTHEAST THROUGH THE AREA MONDAY EVENING...THEN
SOUTHEAST OF THE AREA LATER MONDAY NIGHT. THEY ALSO BRING
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION INTO THE AREA MONDAY
NIGHT. THE ECMWF KEEPS THE 850MB BAROCLINIC ZONE OVER THE AREA
THROUGH THE NIGHT...WITH THE SHORTWAVE TROUGH STILL WEST OF THE
REGION. WILL FOLLOW THE NAM/GFS/CANADIAN TRENDS AND KEEP LIKELY
POPS GOING IN THE SOUTHEAST CORNER OF THE AREA...WITH CHANCE POPS
ELSEWHERE.
GFS/ECMWF CONTINUE TO DIFFER ON TUESDAY...WITH THE ECMWF BRINGING
A MORE AMPLIFIED SHORTWAVE TROUGH THROUGH THE REGION. THIS HELPS
CYCLOGENESIS WITH THE DOWNSTREAM SURFACE LOW. THE GFS IS LESS
AMPLIFIED BUT STILL BRINGS THIS FEATURE THROUGH THE AREA. GFS ALSO
SHOWING MID LEVEL FRONTOGENESIS BAND STAYING WEST AND NORTH OF THE
AREA. STILL...BOTH MODELS SHOWING LIGHT QPF OF UP TO 0.15 INCHES
ON THE ECMWF ON TUESDAY. WILL CONTINUE LIKELY POPS FOR LIGHT SNOW.
AT THIS TIME...IT APPEARS THAT SNOW ACCUMULATIONS WOULD BE ON THE
LIGHTER SIDE THAN PREVIOUSLY THOUGHT. STILL...THIS SYSTEM NEEDS TO
BE WATCHED IN CASE IT SLOWS DOWN AND AMPLIFIES. BRISK NORTHWEST
WINDS WILL BRING COLDER AIR INTO THE AREA...AND WOULD HELP BLOW
AND DRIFT ANY NEW FALLEN SNOW. STAY TUNED.
LONG TERM...TUESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE
LOW TO MEDIUM.
WEAK HIGH PRESSURE RIDGE TUESDAY NIGHT BRINGS QUIET
WEATHER...BEFORE ECMWF/GFS SHOW DIFFERENCES WITH WEAKER SYSTEMS
FOR THE REST OF THE WEEK. THEY BRING ALBERTA CLIPPER SYSTEM
SOUTHEAST THROUGH THE REGION LATER WEDNESDAY INTO WEDNESDAY
NIGHT...GFS QUICKER THAN THE ECMWF. THESE MODELS THEN DIFFER QUITE
A BIT WITH FEATURES LATER IN THE WEEK. FOR NOW...WILL GO WITH
CONSENSUS POPS AND TEMPERATURES FOR THIS PERIOD GIVEN THE FAIR
AMOUNT OF UNCERTAINTY FROM THE MODELS.
AVIATION/12Z TAFS/...BACK EDGE OF MVFR CEILINGS OVER SW WI HAS BEEN
MOVING STEADILY EWD AROUND 12KTS...BUT HAVE NOTICED A SLIGHT SLOWING
IN LAST SEVERAL 11-3.9 MICRON IMAGES SINCE 08Z. WEAK CYCLONIC
CURVATURE AND BULK OF LOW LEVEL MOISTURE IN DENDRITIC GROWTH ZONE WL
CONTINUE TO SHAKE OUT FEW FLURRIES THIS MRNG ESPECIALLY IN SOUTHEAST
AS SLIGHTLY DRIER AIR SETTLES IN FROM THE NORTH.
WL GRADUALLY RAISE CEILINGS IN EAST TO VFR BUT LOW CLOUDS COULD VERY
WELL HANG ON ALL DAY AS LOW LEVEL THERMAL TROUGH WL BE SLOW TO MOVE
OFF TO THE EAST. WL HOLD ONTO LOW VFR CIGS IN EAST WITH A SMALL
THREAT FOR VERY LIGHT SNOW THIS EVE AS WEAKENING SHORT WAVE SLIDES
THRU THE REGION. WL TAKE CIGS AND VSBYS BRIEFLY DOWN IN KMSN AS
SOUTH CENTRAL WI WL BE CLOSER TO DEEPER MOISTURE AND BETTER WEAK
LIFT.
MARINE...QUIET CONDITIONS EXPCD IN THE SHORT TERM AS WEAK HIGH
PRESSURE LINGERS OVER LAKE MI INTO TNGT. STRENGTHENING LOW PRESSURE
IS EXPECTED TO MOVE THROUGH SRN CANADA ON SUN AND MON RESULTING IN A
TIGHTENING PRESSURE GRADIENT OVER THE WRN GTLAKES. THE LOW WILL
PULL A COLD FRONT THROUGH THE AREA ON MONDAY RESULTING IN BRISK SW
WINDS TURNING TO THE N-NW. WIND SPEEDS WL LIKELY REACH SMALL CRAFT
LEVELS DURING THIS PD.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...WIMBERLEY/DDV
TODAY/TONIGHT AND AVIATION/MARINE...MBK
SUNDAY THROUGH FRIDAY...WOOD