FXUS61 KBGM 262351
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
651 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 TUESDAY/...
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 /TUESDAY NIGHT THROUGH SATURDAY/...
AFTER OUR BRIEF HOLIDAY WRM UP...THE FCST AREA WILL FALL BACK INTO
THE COLD WITH A LRG UPR TROF FOR THE ERN US. THIS BLOCKY PTRN IS
ALL SET TO PRODUCE ANOTHER MAJOR STORM AND THE ECMWF HAS NOW FOR
SVRL RUNS DECIDED THAT THIS WILL HAPPEN NEAR THE NEW YEAR. GFS AND
IT/S ENSEMBLES SHOW A MORE OPEN SYSTEM FOR THE END OF THE PD...BUT
WLD ALSO BRING SNOW TO THE AREA. GIVEN THE GFS/S COMMON ERROR OF
BRKG DOWN BLOCKY RDGS TOO QUICKLY...THE ECMWF MAY END UP BEING THE
CORRECT SOLN...MEANING A PTNL STORM IS LOOMING FOR THE NEXT
HOLIDAY. SO...FOR THE XNTDD PD HAVE GONE WITH A CHANCE OF SNOW
NEARLY EVERY PD...AND HAVE CHGD FROM SNOW SHWRS TO STRATIFORM SNOW
TO INDICATE THE MORE WIDESPREAD AND STEADY NATURE OF THE UPCOMING
WX. FOR TEMPS...STARTED WITH HPC GUIDE WHICH SEEMED TO BE CLOSE TO
THE ECMWF...BUT LWRD THEM A BIT TO REFLECT THE GNRL COLD
CONDS...AND IVE A SLGT NOD TO THE GFS IN CASE A MORE OPEN SOLN IS
CORRECT.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
LRG UPR LOW CONTS TO CNTRL THE WX FOR THE REGION. GUSTY WINDS THIS
EVE WILL WEAKEN AS THE GRADIENT RELAXES...AND WEAK SFC BNDT
APRCHS. THIS BNDRY IS REALLY JUST THE LEADING EDGE OF DRIER
AIR...AND A SHIFT TO MORE WLY WINDS LTR TNGT AND ON SUNDAY. AHD OF
THE BDNRY...LGT SHWRS AND LWRD CIGS WILL KEEP MVFR CONDS IN THE
AREA...BHD THE BNDRY...VFR CONDS WILL RETURN. VERY GUSTY WINDS
EARLY IN THE EAST WILL SUBSIDE BEFORE 03Z...WITH LGT SOUTH TO WEST
WINDS LATE TNGT AND SUNDAY.
.OUTLOOK...
SUN NGT/MON/TUE...MVFR...WITH AREAS OF LAKE EFFECT SNOW...MOSTLY AT
NY SITES.
WED/THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG/DJN
NEAR TERM...CMG/DJN
SHORT TERM...DJN
LONG TERM...DGM
AVIATION...DGM
