FXUS61 KBGM 262012
AFDBGM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
312 PM EST SAT DEC 26 2009

.SYNOPSIS...
A LARGE AREA OF LOW PRESSURE WILL TRACK SLOWLY INTO THE GREAT
LAKES REGION THROUGH SUNDAY, AND THEN ACROSS THE NORTHEAST BY MONDAY.
THIS LOW WILL BRING LIGHT SNOW TO THE REGION SUNDAY NIGHT AND
MONDAY. AFTER THIS LOW PASSES BY, MUCH COLDER ARCTIC AIR WILL PUSH
DOWN INTO THE REGION WITH LAKE EFFECT SNOW SHOWERS AND FLURRIES
MONDAY NIGHT THROUGH TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
FOR THIS EVENING AND OVERNIGHT...MODELS SHOW A STRONG
SOUTHEASTERLY LOW-LEVEL JET FROM NJ ACROSS NORTHEAST PA TO CENTRAL
AND EASTERN NY. THIS JET WAS ASCENDING ESPECIALLY ON THE WESTERN
EDGE WHERE ISEN LIFT AND LOW-LVL CONVERGENCE WAS STRONGER. HENCE
PRECIPITATION WAS ENHANCED NEAR THE WRN EDGE ACROSS WESTERN
NY/NORTH CENRAL PA WITH A LOCAL MINIMUM FARTHER EAST IN THE CORE
OF THE LOW-LEVEL JET. THIS JET SLIDES OFF TO THE NORTHEAST THIS
EVENING HOUR AND THE REST OF CENTRAL NY AND NORTHEAST PA GETS INTO
THE MORE CONVERGENT AND ASCENDING WRN SIDE OF THE JET CORE. THUS
BELIEVE BACK EDGE OF THE LIGHT RAIN AND DRIZZLY PRECIP WILL
CORRELATE WELL TO THIS EDGE. WILL TIME ENDING OF PRECIP WITH THIS
FEATURE AS IT WORKS TO THE NE TONIGHT. BACK EDGE SHUD REACH FAR
NORTHEAST CWA BY 9Z-12Z. MODEL SOUNDINGS DO NOT SHOW ANY CLOUDS
HIGH ENOUGH FOR ICE CRYSTAL PRODUCTION HENCE ALL LIQUID PRECIP
EXPECTED WITH RAIN AND DRIZZLE. TEMPERATURES WILL REMAIN ABOVE
FREEZING BEFORE PRECIPITATION ENDS...SO NOT EXPECTING ANY MORE
FREEZING PRECIP.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
AFTER THIS PRECIPITATION FINALLY PUSHES OFF TO THE NORTHEAST EARLY 
SUNDAY...PA AND NY WILL BE IN A COLD ADVECTION PATTERN ON A  
LOW-LEVEL SOUTHWESTERLY FLOW SUN AM. THE INCREASING SOUTHWESTERLY 
FLOW WAS ASSOCIATED WITH THE LARGE DYING OCCLUDED LOW AND 
ASSOCIATED UPPER LEVEL LOW WITH THE MAJOR BLIZZARD IN THE PLAINS. I 
DON/T SEE A LOT OF PRECIP ON SUNDAY AS REGION IS IN BETWEEN SHORT 
WAVES ALOFT. 

THE UPPER LEVEL LOW AND UPPER SHORT WAVE ALOFT ASSOCIATED WITH THE 
PLAINS BLIZZARD WILL WORK EAST AND SPREAD LIGHT SNOW TO MUCH OF 
FORECAST AREA SUN NGT AND EARLY MON. THIS UPPER LEVEL FEATURE WILL 
SUPPORT STRG LOW-LVL ISENTROPIC LIFT ARND THE 280-285K SFC INTO NRN 
PA AND SRN NY BELOW DECENT MID LVL LIFTG AND COOLING AS PER THE 
LOCAL PRESSURE DERIVATIVE TERM. THE WAVE WILL MOVE QUICKLY AND WILL 
NOT HAVE A LOT OF MOISTURE ASSOCIATED WITH IT SINCE THE DEEPER 
MOISTURE WITH THIS DECAYING CYCLONE WILL REMAIN WELL OFF TO THE 
EAST. THE LIFTING WITH THIS FEATURE WAS CLOSE TO THE MAXIMUM ICE 
CRYSTAL GROWTH ZONE SO I EXPECT ABOUT 15-1 SNOW TO LIQUID RATIOS.

QPF VARIES AS PER MODEL RUN. NAM HAS .25 TO .45 INCH IN THE TWIN 
TIER REGION WITH .1 TO .25 NORTH AND SOUTH OF THIS AREA IN THE BGM 
CWA. ECMWF HAS .1 TO .25 MOST OF CWA. GFS IS FARTHER NORTH WITH
THE UPPER LEVEL LOW AND HENCE HAS UP TO .25 QPF IN THE NRN CWA
WITH LESS IN THE SOUTH. LOCAL WRF HAS ARND .1 TO .25 INCH QPF. AT
THIS POINT IT LOOKS LIKE THE POTENTIAL FOR A LOW END ADVY
EVENT...2-5 INCHES. WILL MENTION IN HWO.

AFTER THIS SYSTEM PASSES BY MON...ANOTHER SHORT WAVE DROPS SOUTH 
WITH ARCTIC AIR AS STRG LL NW FLO SETS UP WITH 850 MB TEMPS PLUNGING 
TO SUB -20C. THIS WILL BE A GOOD PROLONGED MULTIBAND LAKE EFFECT 
SNOW EVENT TUE INTO WED. WUDN'T BE SURPRISED TO SEE LAKE EFFECT ADVY 
AMOUNTS. WIND CHILL MAY BECOME AS ISSUE AS WELL. WILL HIGHLIGHT IN 
HWO.  

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UPDATED AS OF 245 AM...
A VIGOROUS UPPER-LEVEL WAVE IS PROGGED TO CROSS THE REGION SUNDAY
NIGHT...BRINGING A CHANCE OF SNOW SHOWERS/LIGHT SNOW TO MUCH OF
THE AREA.

FROM MONDAY INTO WEDNESDAY...MUCH COLDER TEMPERATURES AND AREAS OF
LAKE-EFFECT SNOW SHOWERS WILL BE THE MAIN WEATHER STORIES. THE
BEST CONCENTRATION OF SNOW SHOWERS MAY COME MONDAY NIGHT INTO
TUESDAY...ALONG AND JUST BEHIND AN ARCTIC FRONTAL BOUNDARY. FROM
THIS EARLY VANTAGE POINT...IT LOOKS LIKE THE LOW-LEVEL FLOW MAY
START OUT 290-300 BEHIND THE FRONT...ULTIMATELY VEERING TO AROUND
320. THIS WOULD LIKELY MEAN A MULTI-BAND SET UP FOR MUCH OF
CENTRAL NY. 

LATER WEDNESDAY INTO THURSDAY...SNOW SHOWERS MAY BE ON THE
WANE...AS MODEL CONSENSUS HAS HIGH PRESSURE BRIEFLY BUILDING IN. 

TOWARDS THE END OF THE WEEK/START OF THE NEW YEAR...A LARGE-SCALE
PATTERN THAT POTENTIALLY FAVORS AN EAST COAST STORM COULD
DEVELOP...WITH PRONOUNCED GREENLAND BLOCKING...AND A POSITIVE PNA SET UP.
THE EURO/CANADIAN MODELS SHOW THIS MOST STRONGLY...DEVELOPING A
MAJOR STORM ALONG THE MID-ATLANTIC COAST...WHILE THE GFS IS MORE
SUPPRESSED...KEEPING ANY EFFECTS FROM SUCH A SYSTEM WELL TO OUR
SOUTH...WITH JUST A CONTINUATION OF SNOW SHOWERS/FLURRIES IN A
COLD NORTHWEST FLOW PATTERN. FOR NOW...WE'LL PLAY IT
CONSERVATIVELY...AND CONTINUE TO CALL FOR JUST A CHANCE OF SNOW
SHOWERS. WE'LL BE WATCHING THIS SITUATION AS THE WEEK UNFOLDS.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
GUSTY SOUTHEAST WINDS PREVAIL ACROSS THE REGION THIS AFTERNOON IN
RESPONSE TO A LOW-LEVEL JET PASSING ACROSS THE AREA. SUSTAINED
WINDS IN EXCESS OF 20 KTS ARE PREVALENT AT ALL TAF SITES WITH THE
EXCEPTION OF KSYR...WITH 30 KT NOW SUSTAINED AT KBGM. ELEVATED
WINDS WILL PERSIST THROUGH THE REMAINDER OF THE AFTERNOON BEFORE
BEGINNING TO TAPER OFF THIS EVENING AS THE LOW-LEVEL JET
PROPAGATES AWAY FROM THE REGION.

NEXT ITEM OF CONCERN CONTINUES TO BE -RA MOVING ACROSS THE AREA.
REGIONAL RADAR MOSAIC SHOWS A TEMPORARY LULL ACROSS MOST
LOCATIONS AT THE PRESENT TIME...WITH MORE SUBSTANTIAL PRECIP
FURTHER SOUTH ACROSS SOUTHEAST PA/NJ IN RESPONSE TO A DEVELOPING
LOW PRESSURE CENTER. EXPECT RA TO BECOME MORE WIDESPREAD BY LATE
AFTERNOON/EVENING AS AN OCCLUDED BOUNDARY/TROUGH BEGINS MOVING THROUGH
THE AREA. PERIODS OF MODERATE RA CAN BE EXPECTED AFTER 00Z...WITH
MVFR/IFR VSBYS/CIGS BECOMING MORE WIDESPREAD. PRECIP EXPECTED TO COME
TO AN END AFTER 08Z FROM WEST TO EAST AS DRIER AIR BEGINS WORKING
INTO THE REGION. MVFR/IFR CIGS TO PREVAIL AFTER THE RA DEPARTS TO
THE EAST AS MOISTURE REMAINS TRAPPED BELOW A LOW-LEVEL INVERSION.
EXPECT IMPROVING CONDITIONS AFTER 14Z AS LOW-LEVELS BEGIN TO WARM.

.OUTLOOK...
SUN/MON/TUE...MVFR...WITH AREAS OF LAKE EFFECT SNOW...MOSTLY AT
NY SITES. 
WED...VFR.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.

&&

$$
SYNOPSIS...CMG/DJN
NEAR TERM...CMG/DJN
SHORT TERM...DJN
LONG TERM...MLJ
AVIATION...CMG