Heavy Snow in New York, March 20, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
305 AM EST WED MAR 20 2002

ITS TIME TO PAY FOR THE MILD WINTER.

LLVL THERMAL AND MOISTURE ADVECTION IS INCRG UNDERNEATH THERMALLY
DIRECT CIRCULATION IN THE ENTRANCE REGION OF UPR JET AND LIGHT SNOW
SHIELD RAPIDLY DVLPG ACROSS NE PA AND SRN TIER NY. SFC TEMPS
MARGINAL FOR STICKING SNOW...BUT WHOLE COLUMN IS PLENTY COLD ENOUGH
TO KEEP PTYPE ALL SNOW DURING THESE WEE HOURS BEFORE DAWN. MODELS
ARE IN FAIR AGREEMENT ON THE MASS FIELDS THAT SHOW WK SFC
CYCLOGENESIS TDY ACROSS NRN VA WITH INVERTED TROF POKING INTO WRN NY
AND SCNDRY WK LOW DVLPG AS TRAILING NRN STREAM TROF SWINGS INTO
AREA. WL FOLLOW THE AVN WHICH HAS BEEN ROCK SOLID WITH EVOLUTION OF
THIS SYSTEM...AND THE ONE A COUPLE DAYS AGO...LET ALONE THE FACT IT
HAS BEEN THE MARGINALLY SUPERIOR ONE AROUND HERE THIS CRAZY WINTER.

THE SENSIBLE WX TODAY WILL BE ONE OF THOSE CLASSIC ELEVATION
DEPENDENT SNOW FALLS THIS MORNING WITH AVN QPF VALUES INDICATING A
QUARTER TO HALF INCH LIQUUID QPF TODAY. PERFORMANCE OF ALL MODELS
LATELY HAS BEEN TO BRING A LTL TOO MUCH QPF NORTH OF THE MAIN
FRONTAL BNDRY IN THE TN VALLEY AND MID ATLANTIC. ETA SEEMS QUITE
OVERDONE...LIKELY AS A RESULT OF OVERDEEPENING SFC LOW PER NCEP
DISCN. AVN EVEN SEEMS A TAD HIGH IN NE PA...BUT EVEN SO...A LOT OF
THAT QPF WL BECOME LIQUID THIS MORNING. HRLY SOUNDINGS DONT
INDICATE AS MUCH OF A PUNCH OF WARM AIR ALOFT AS STORM A FEW DAYS
AGO...SO THE ISSUE OF MIXING ALL PTYPES IS MOOT AND THIS WL BE A
LIQUID VS. SNOW SITN. WITH RATIOS WORSE THAN 10:1 (MORE LIKE 5-8:1)
WELL SEE UP TO 3 INCHES OVER THE HIGHER TERRAIN (CATS/POCS/WRN
STEUBEN) AND ONLY A COATING IN THE VALLEYS. SNOW THIS AM...WL CHANGE
TO RAIN IN THE VALLEYS AND MIX WITH IT HILLTOPS TWD MIDDAY. COLDEST
AIR WL BE TRAPPED WHERE IT USUALLY IS IN THE MHWK VLY AND WRN CATS
AND WL BE HARD TO FULLY CHANGEOVER.

SFC TROF AND H7 S/WV ARE MOVING PAST THE AREA BY 00Z WHICH WL CUT
OFF MOST OF PRECIP. H5 TROF LAGS JUST A BIT BEHIND SO XCPT FOR THE
ERN ZONES ILL SHOW A TAPERING OFF TREND TO LIGHT RAIN SHOWERS LATE
TODAY...THEN JUST A FEW FLURRIES OR DRIZZLE EARLY TONIGHT BEFORE
MODELS INDICATE A FAIR AMT OF SYNOPTIC DRYING LATE. ITS LIKELY THAT
LOW CLOUDS WL BE TRAPPED...SO WL JUST KEEP IT M/CDY TO ACCOUNT FOR
SOME BREAKS DUE TO DRYING ALOFT.

GUIDANCE TEMPS HAVE BEEN RUNNING WARM LAST SVRL DAYS AND AT SOME
STATIONS THE FWC HAS BEEN >5 DEGS OFF. FWC/MAV CLOSE SO WL GO AT OR
SLIGHTLY BLO THE NUMBERS WHICH KEEPS MOST AREAS IN THE 30S. VALLEYS
OF NEPA AND FINGER LAKES SHOULD BE 40-ISH.

THURS MORNING WILL START OUT TRANQUIL...BUT THE END OF THE FIRST
FULL DAY OF SPRING WILL BE A SHOCK AS ARCTIC FRONT IS UNLEASHED UPON
US. HARD TO JUSTIFY SUCH BALMY TEMPS AS THE UPR 40S-LOW 50S THAT WE
HAVE IN FCST ESPLY SINCE THEY WL OCCUR AROUND MIDDAY. GUIDANCE TREND
HAS BEEN DOWNWARD SO...IN THE SPIRIT OF MOS BEING TOO WARM LATELY...
ILL CUT BACK ON MAXES TOMORROW BY A CATEGORY. FRONT WL BE SLICING
THRU
THE REGION FROM 20Z ONWARD WITH TEMP FALLS OF 20 DEGS NOT OUT OF THE
QUESTION BY 00Z. ALL THIS ACCOMPANIED BY BLUSTERY WINDS AND LAKE
ENHANCED SNOW SQUALLS THAT WILL LIKELY TRANSLATE ALL THE WAY INTO NE
PA.

AS COLD AIR DEEPENS THURSDAY NIGHT AND FRIDAY WITH STRONG CYCL FLOW
ALOFT LAKE ONTARIO WILL COME VERY MUCH ALIVE AS CONDITIONAL
INSTABILITY GOES EXTREME WITH -24C AIRMASS REACHING INTO NE PA AND A
MODERATE WIND FLOW FOR SNOW SHOWERS ACROSS THE AREA THRU FRIDAY
NITE. NO OTHER ADJUSTMENTS TO REST OF FCST.

.BGM...NONE.

BREWSTER