FXUS61 KALY 091748
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1248 PM EST WED DEC 9 2009
.SYNOPSIS...
A POWERFUL STORM WILL MOVE ACROSS MICHIGAN THIS AFTERNOON...AS A SECOND
LOW PRESSURE SYSTEM MOVES NORTHEAST OF LONG ISLAND. THE COMBINATION OF
THESE TWO STORMS WILL SPREAD A VARIETY OF WINTER WEATHER INTO THE
REGION INTO THE AFTERNOON. AS THE MAIN LOW PRESSURE SYSTEM TRACKS
INTO CANADA ON THURSDAY...A BRISK FLOW OF COLDER AIR WILL FOLLOW
IN ITS WAKE WITH HEAVY LAKE EFFECT SNOW POSSIBLE ACROSS THE
ADIRONDACKS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1240 PM EST...A THIRD UPDATE TODAY TO DROP THE WINTER STORM
WARNINGS FOR THE NRN CATSKILLS...GREATER CAPITAL
REGION...TACONICS...SCHOHARIE VALLEY...HELDERBERGS...BERKSHIRES
AND THE WEST CENTRAL MOHAWK VALLEY.
THE DRY SLOT ASSOCIATED WITH THE POWERFUL PRIMARY LOW /975 HPA/
OVER NRN MI CONTINUES TO MOVE INTO THE REGION. THE COMPACT SFC LOW
NEAR LONG ISLAND /993 HPA/ CONTINUES TO SHIFT THE NE. THIS
SECONDARY LOW COUPLED WITH THE RETREATING SFC HIGH LOCKED ENOUGH
COLD AIR FOR PRIMARILY A SNOW EVENT. THE LOW LEVEL AGEOSTROPIC
FLOW CONTINUED FROM THE N/NE FOR AN EXTENDED PERIOD OF TIME...IN AND
JUST ABOVE THE BOUNDARY LAYER. THE COLD AIR DAMMING FROM THIS
STORM SYSTEM IS IMPRESSIVE WITH SHALLOW COLD AIR IN PLACE EAST OF
THE APPALACHIANS DOWN INTO GA !
THE WARNING WILL CONTINUE FOR THE SRN ADIRONDACK REGION...LAKE
GEORGE NRN SARATOGA REGION....AND SRN VT. SOME LIGHT ADDITIONAL
SNOW ACCUMULATIONS ARE LIKELY. ALSO SOME POCKETS OF LIGHT RAIN OR
FREEZING DRIZZLE WILL PERSIST SOUTH OF THE WARNING AREA.
PLEASE SEE OUT LATEST PUBLIC INFO. STATEMENT. SOME HEFTY TOTALS IN
THE HELDERBERGS...CNTRL MOHAWK VALLEY...SRN GREENS...SRN
ADIRONDACKS...AS WELL AS LAKE GEORGE SARATOGA REGION.
...PREVIOUS UPDATE...
ANOTHER UPDATE TO DO THE FOLLOWING...
1. TO DROP THE FLOOD WATCH FOR ULSTER...DUTCHESS...AND LITCHFIELD
COUNTIES. MOST THESE AREAS HAD 4-9 INCHES OF SNOWFALL BEFORE A
QUICK TRANSITION TO MAINLY LIGHT RAIN. ADDITIONAL QPF LOOKS LIKE
IT WILL BE UNDER A QUARTER OF AN INCH. THE LATEST RIVER FORECASTS
LOOK FINE.
2. WE HAVE DROPPED THE WINTER WEATHER ADVISORIES FOR DUTCHESS AND
LITCHFIELD COUNTIES. THE PCPN HAS TRANSITIONED TO SPOTTY LIGHT
RAIN WITH POCKETS OF FREEZING RAIN.
3. WE DROPPED THE WINTER STORM WARNING FOR ULSTER COUNTY...AS THE
PCPN HAS DIMINISHED BASED ON THE LOCAL RADARS.
WE BEEFED UP THE WINDS TO GUSTS OF 45 MPH IN WASHINGTON CO.
DOWNSLOPING IS EVIDENT ON THE VAD WIND PROFILED. PORTIONS OF WRN
BENNINGTON HAVE ONLY RECEIVED 2-4" DUE TO THE E/SE WINDS KDDH HAD
A GUST TO 46 MPH...AND NORTH ADAMS MA TO 48 MPH. ALSO...OUR COOP
SPOTTER IN SUNDERLAND VT HAD A GUST LAST HR TO 43 MPH.
BOTTOM LINE...WIND ADVISORY CONTINUES FOR SOUTHERN
VERMONT...BERKSHIRE COUNTY...AND TACONICS.
PLEASE SEE OUR LATEST PUBLIC INFO STATEMENT WHERE 4-9" OF SNOW HAVE
FALLEN ACROSS MUCH OF THE REGION. SOME RAIN IS MIXING IN OVER THE
MID HUDSON VALLEY AT THIS TIME
MOST THE REGION WILL RECEIVE 5-12" OF SNOW WITH THE HEAVIEST TOTALS
NORTH OF THE MOHAWK RIVER VALLEY...AND OVER THE ERN CATSKILLS.
ALSO...WITH UNOFFICIALLY 7.1" OF SNOW AT 10 AM AT THE ALBANY
NWS/CESTM...THAT WILL LAUNCH US ABOVE NORMAL FOR THE SEASON.
DECEMBER...HAS COME ROARING LIKE A LION WITH THE WINTRY
WEATHER...WITH THE MILD AND SNOWLESS NOVEMBER 2009 A DISTANT
MEMORY !!!
WE WILL UPDATE AGAIN AROUND THE LUNCH TIME HOUR TO LIKELY DROP
MORE OF THE HEADLINES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AS UPPER LEVEL SHORTWAVE...AND OCCLUDED FRONT PASS NE ACROSS REGION
THIS EVENING...ANOTHER BRIEF BURST OF SHOWERS ARE EXPECTED. IN
FACT...PREVIOUS MODEL RUNS HINTED AT SOME ELEVATED INSTABILITY...AND
WOULD NOT COMPLETELY RULE OUT AN ISOLATED RUMBLE OF THUNDER.
THEN...AS SUBSIDENCE DEVELOPS IN THE WAKE OF THESE FEATURES...WE
EXPECT PRECIP TO TAPER OFF WITHIN THE VALLEYS...WHILE SOME SNOW
SHOWERS DEVELOP ACROSS HIGHER ELEVATIONS...ESP WITHIN THE DACKS
LATER TONIGHT. WINDS WILL INCREASE FROM THE SW/W LATER TONIGHT...BUT
SHOULD REMAIN BELOW ADV LEVELS. AS FOR MIN TEMPS...GENERALLY SIDED
WITH THE MET MOS.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
DECENT PRESSURE GRADIENT ACROSS THE GREAT LAKES THURSDAY WITH WEST
TO SOUTHWEST LOW LEVEL FLOW TRENDING TO WEST AND NORTHWEST THROUGH
THURSDAY NIGHT...FRIDAY AND FRIDAY NIGHT. LAKE EFFECT SNOWS WILL
AFFECT THE SOUTHERN ADIRONDACKS...TRENDING FROM NORTHERN HERKIMER
AND HAMILTON COUNTIES THURSDAY...TO CENTRAL AND SOUTHERN HERKIMER
AND HAMILTON COUNTIES THURSDAY NIGHT THROUGH FRIDAY NIGHT.
SCATTERED SNOW SHOWERS EXPECTED IN CATSKILLS...SOUTHERN GREEN
MOUNTAINS AND BERKSHIRES THROUGH THE PERIOD WITH THE UPSLOPE FLOW.
ISOLATED SNOW SHOWERS IN MANY VALLEY AREAS...EXCEPT PERHAPS IN POU
AREA AND NW CT. BASED ON PREDICTED DEPTH OF MOISTURE AND
INSTABILITY OFF THE LAKES...CONSIDERABLE SNOW EXPECTED IN THE
SOUTHERN ADIRONDACKS...AND LAKE EFFECT SNOW HEADLINES WILL PROBABLY
BE NEEDED ONCE OUR CURRENT EVENT IS DONE.
BASED ON CLOUD COVER AND PREDICTED BOUNDARY LAYER TEMPERATURES AND
POTENTIAL MIXING FROM GUSTY WINDS...HIGHS IN THE LOW TO MID 30S
THURSDAY...WITH 20S IN MOUNTAINS. LOWS THURSDAY NIGHT AND FRIDAY
NIGHT IN THE TEENS...WITH SINGLE NUMBERS IN MOUNTAINS. HIGHS FRIDAY
AND SATURDAY IN THE 20S TO LOWER 30S...WITH AROUND 20 IN THE
MOUNTAINS.
SATURDAY NIGHT THROUGH SUNDAY...HIGH PRESSURE BUILDS INTO THE AREA
FROM THE TN VALLEY AS LOW PRESSURE FINALLY LIFTS OUT OF SOUTHERN
CANADA. LONG RANGE GUIDANCE TRYING TO HINT AT ANOTHER SYSTEM
POTENTIALLY THREATENING SOME PART OF THE EASTERN U.S. IN THE SUNDAY
NIGHT THROUGH TUESDAY TIME FRAME. SPREAD IN GUIDANCE VERY LARGE IN
TERMS OF TIMING AND PLACEMENT OF KEY FEATURES. SO...DID NOT CHANGE
MUCH IN THE SUNDAY NIGHT THROUGH TUESDAY TIME FRAME...EXCEPT TO WARM
TEMPERATURES A FEW DEGREES DUE TO POTENTIAL CLOUD COVER...AND
MOISTURE ADVECTION...AND PUTTING SLIGHT CHANCES FOR PRECIPITATION.
LOWS SATURDAY NIGHT IN SINGLE NUMBERS TO MID TEENS...WITH
POTENTIALLY NEAR ZERO IN THE ADIRONDACKS. HIGHS SUNDAY THROUGH
TUESDAY IN THE LOWER TO MID 30S...WITH 20S IN MOUNTAINS. LOWS
SUNDAY NIGHT AND MONDAY NIGHT IN THE UPPER TEENS TO LOWER
20S...SINGLE NUMBERS IN THE ADIRONDACKS.
MJO TRYING TO REEMERGE INTO A WEAK PHASE 8...BUT WILL SEE IF THAT
TREND CONTINUES...WHICH WOULD FAVOR GENERAL LOW PRESSURE IN EASTERN
NORTH AMERICA. CONSIDERING THE RESPECTABLE CORE OF COLD AIR THAT
CROSSED THE POLE INTO CANADA RECENTLY...MANIFESTING ITSELF AS
MULTIPLE UPPER SYSTEMS ROTATING AROUND A MEAN POLAR VORTEX IN
NORTHERN CANADA...GRADUALLY COLDER AIR WORKING INTO EASTERN U.S.
THE MEAN UPPER TROUGH AXIS IN THE CENTRAL U.S. HAS BEEN
CONTRIBUTING TO A PATTERN IN PAST WEEKS IN WHICH THE GULF OF MEXICO
HAS BEEN OPEN FOR BUSINESS AND STORMS TRACK THROUGH OR OFF THE
EASTERN U.S. THE PATTERN IN THE LONG RANGE IS RIPE FOR POTENTIAL
NORTHERN AND SOUTHERN STREAM PHASING INTO A BIG STORM...BUT
POTENTIAL IS NOT ALWAYS REALIZED...SO WITH THE HINTS AT PIECES OF
THE PUZZLE EXISTING...BUT NOT NECESSARILY FITTING TOGETHER
YET...WILL CONTINUE TO WATCH THE PATTERN EVOLUTION.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
STILL LESS THAN IDEAL CONDITIONS WITH IFR/MVFR CIGS AND VIS ACROSS
THE REGION...EVEN THOUGH THE BULK OF THE PRECIP HAS MOVED EAST OF
THE REGION. THERE SEEMS TO BE A LITTLE MESOSCALE LIGHT PRECIP BAND
DEVELOPING OVER THE HUDSON RIVER BUT THIS SHOULD BE SHORT LIVED AS
STORM CENTER OFF THE NEW ENGLAND COAST LIFTS NORTHEAST. IMPRESSIVE
WIND FIELD ASSOCIATED WITH THIS STORM AND WE WILL LEAVE LLWS IN THE
TAFS THROUGH THE AFTERNOON AND EARLY EVENING. COLD FRONT TO PUSH
THROUGH THIS EVENING AS THIS SHOULD ALLOW FOR WEST-SOUTHWEST WINDS
TO BECOME MORE PREVALENT AND INCREASE OVERNIGHT THROUGH THURSDAY.
OUTLOOK...
THU-SAT...WINDY. VFR-MVFR FOR MAINLY CIGS WITH CHC -SHSN AT THE TAF
SITES AND LAKE EFFECT SNOW DEVELOPING DOWNWIND FROM LAKE ONTARIO AND
UPSLOPE SNOW IN THE SOUTHERN GREEN MOUNTAINS AND NORTHERN/CENTRAL
TACONICS.
SAT NT...VFR...NO SIG WX.
SUN...VFR TO MVFR...CHC IFR. CHC -SN.
&&
.HYDROLOGY...
THE FLOOD WATCH HAS BEEN CANCELED FOR ULSTER...DUTCHESS AND
LITCHFIELD COUNTIES. SNOW THAT FELL EARLIER THIS MORNING WILL
SOAK UP MOST...IF NOT ALL...OF THE RAIN THAT CAME LATER.
SOME SLIGHT INCREASES IN FLOW WILL OCCUR ON THE RONDOUT...
WAPPINGERS...TENMILE...AND HOUSATONIC RIVERS. FARTHER NORTH...
RIVERS WILL CONTINUE TO RECEDE.
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...WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NYZ054-061.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR NYZ032-
033-041>043-082>084.
MA...WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MAZ001-025.
VT...WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR VTZ013-014.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR
VTZ013>015.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...KL
LONG TERM...NAS
AVIATION...BGM
HYDROLOGY...RCK
