FXUS61 KBGM 241913
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
213 PM EST THU DEC 24 2009
.SYNOPSIS...
DRY WEATHER CAN BE EXPECTED THROUGH TONIGHT AS HIGH PRESSURE NOSES
INTO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA. BY CHRISTMAS
MORNING...RETURNING MOISTURE WILL BRING THE CHANCE FOR LIGHT
FREEZING DRIZZLE. A STORM SYSTEM WILL THEN APPROACH FROM THE WEST
DURING THE DAY WITH THE POTENTIAL FOR RAIN OR FREEZING RAIN...MAINLY
FOR AREAS WEST OF INTERSTATE 81. PRECIPITATION WILL OVERSPREAD THE
ENTIRE AREA FRIDAY NIGHT WITH FREEZING RAIN POSSIBLE THROUGH
SATURDAY MORNING...MOST LIKELY OVER THE WESTERN CATSKILLS.
PRECIPITATION WILL GRADUALLY WIND DOWN AS SNOW SHOWERS ON
SUNDAY...WITH LAKE EFFECT SNOW SHOWERS THEN EXPECTED THROUGH THE
MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED AT 930 AM...JUST MINOR 1ST PD WEEKS TO CRNT FCST. 12Z
RAOBS SHOW STRONG LOW LVL INVERSION WHICH IS TRAPPING MSTR AND
RESULTING IN XTNSV STRATUS DECK ACRS THE BGM FCST AREA. GIVEN THE
STRENGTH OF THE INVERSION...LOW SUN ANGLE AND SOME UPR CLD MOVG IN
THIS AFTN...WENT A BIT MORE PESSIMISTIC WITH THE CLD COVER AND
DROPPED MAXES BY A FEW DEG. BEST CHC FOR BREAKS OF SUNSHINE
APPEARS TO BE ACRS FAR SE ZONES. OTRW...MAIN FOCUS IS ON TMRW'S
POTNL ICING EVENT. MDLS HAVE BEEN QUITE CONSISTENT (RUN TO RUN AND
ALSO AMONGST DIFFERENT MDLS) AND GIVEN IT'S A HOLIDAY...WE'LL
LIKELY BE PROACTIVE AND ISSUE ADVISORIES THIS AFTN...ASSUMING NO
SUPRISES FROM THE 12Z RUNS. PREV BLO...
AS OF 348 AM...QUIET WX EXPECTED THRU TONIGHT. INVERSION HAS
LOWERED SIGNIFICANTLY TONIGHT...ESSENTIALLY BRINGING AN END TO LK
EFFECT SNOW WITH EXCEPTION OF A FEW SCTD FLURRIES. EXPECT A DRY
DAY AS DRIER AIR MVS IN AND WINDS TURN MORE NERLY COURTESY OF
HIPRES RIDGE BUILDING IN FM CANADA.
LOW CIGS PUSHING SOUTH THRU PA EARLY THIS MRNG ON NRLY H9 FLOW. FLOW
WILL VEER ARND TO THE NE AND THEN EAST BY 18Z WITH CLDS GRADUALLY
ERODING. WILL SHOW IMPRVG CONDS ACRS MOST OF NY BY AFTN WITH PCLDY
SKIES EXPECTED TODAY.
H9 TEMPS RISE TO NR -2C THIS AFTN. THIS WUD YIELD HIGHS NR 40. HWVR
MIXING WILL LKLY NOT OCCUR TO THIS LEVEL AND EXPECT MAXES TO TOP OUT
ONLY IN THE LWR 30S ACRS THE AREA...MID 30S IN VLY LOCATIONS.
H5 LOW CURRENTLY ROTATING THRU TX/OK PANHANDLES WILL EJECT OFF TO
THE NORTH AND EAST AND BCM ABSORBED DROPPING INTO NRN PLAINS.
CONSOLIDATED CLOSED LOW IS EXPECTED TO ROTATE THRU CNTRL PLAINS
TONIGHT WITH H5 RIDGE AMPLIFYING OVR CWA.
1040MB SFC HIGH LOCATED OVR NRN QUEBEC WILL LKLY RESULT IN WEDGING
ACRS A GOOD PART OF THE FA THRU 12Z FRIDAY. THIS FEATURE...COMBINED
WITH H5 LOW LOCATED FAR TO OUR WEST OVR NE/KS...WL LKLY KEEP
MEASURABLE PCPN AT BAY THRU TONIGHT.
00Z NAM12 STILL INDICATING LLM WORKING IN ON SERLY FETCH OFF OF
ATLANTIC LATE TONIGHT...AFFECTING NEPA AND INTO PARTS OF CNTRL SRN
TIER. TO ACCNT FOR THIS HV INCRSD CLD CVR ACRS SRN ZONES AFT ABOUT
09Z TONIGHT. CANNOT RULE OUT SOME LIGHT DRIZZLE TWD DAYBREAK BUT AM
NOT TOTALLY CONVINCED STRATUS LAYER WILL WORK INTO CWA ENUF TO BRING
IN THREAT FOR DRIZZLE/FRZG DRIZZLE. HWVR WILL LKLY SEE LOW CLDS/FOG
ACRS HIGHER TERRAIN OF POCONOS LATE TONIGHT.
TEMPS EXPECTED TO DROP INTO THE TEENS/LOW 20S OVRNGT. HOW FAST THEY
RISE BY MRNG AND HOW QUICKLY DRIZZLE MVS IN WILL DETERMINE WHETHER
ANY TRAVEL PROBLEMS MAY EXIST FOR EARLY CHRISTMAS MRNG TRAVEL.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AS OF 348 AM...LIGHT ICING EVENT EXPECTED FRIDAY INTO SATURDAY...BUT
DUE TO INCREASED HOLIDAY TRAVEL...OVERALL IMPACTS MAY BE
INCREASED. MAIN AREA OF LOW PRESSURE WILL BE ACROSS WEST-CENTRAL
ILLINOIS BY 12Z FRIDAY. A CLASSIC CAD SIGNATURE SHOWS UP ON BOTH
THE NAM AND GFS FROM OUR AREA SOUTH INTO SOUTHWESTERN VIRGINIA.
THIS ALONG WITH A SECONDARY LOW FORMATION FRIDAY NIGHT WILL SET
THE STAGE FOR ICING ACROSS MOST OF THE CWA. THE SAVING GRACE MAY
BE A SOUTHEAST DOWNSLOPING FLOW OF AIR WHICH WILL ACT TO LIMIT QPF
AMOUNTS ACROSS A LARGE CHUNK OF THE AREA.
THE MAIN AXIS OF STEADY PRECIP WILL BE WELL TO OUR SOUTHWEST AS WE
WAKE UP CHRISTMAS MORNING. IT SHOULD BE NOTED THAT SOME AREAS OF
FREEZING DRIZZLE WILL BE POSSIBLE EARLY FRIDAY...WELL AHEAD OF THE
MAIN SHIELD OF PRECIP. THE GFS IS THE ONLY MODEL THAT HINTS AT
SOME LIGHT QPF OVER NORTHERN PA AT THIS POINT. MODEL SOUNDINGS
LOOK GOOD FOR DRIZZLE WITH COMPLETE SATURATION FROM NEAR THE
SURFACE UP THROUGH 2KFT...WITH A PRONOUNCED DRY LAYER ABOVE THAT.
BEST SHOT AT SOME LIGHT FREEZING DRIZZLE EARLY FRIDAY WOULD BE
ACROSS THE HIGHER ELEVATIONS FROM THE SOUTHERN TIER SOUTHWARD.
BOTH THE NAM AND GFS ARE CONSISTENT IN BRINGING IN PRECIPITATION
PRIOR TO SUNSET ACROSS MOST OF THE CWA...WITH CHANCE POPS ON A
LINE FROM SYRACUSE TO BINGHAMTON TO AVOCA...WEST BY SUNSET. IN THE
LAKE PLAIN THIS WILL INITIALLY FALL IN THE FORM OF RAIN BUT
POCKETS OF FREEZING RAIN ARE POSSIBLE ACROSS THE SOUTHERN TIER OF
NY AND NORTHERN PA.
FRIDAY NIGHT A SECONDARY AREA OF LOW PRESSURE WILL DEVELOP OVER
THE MOUTH OF THE CHESAPEAKE BAY. THIS SECONDARY LOW COMBINED WITH
HIGH PRESSURE TO OUR NORTHEAST WILL ENHANCE LOW LEVEL CAD. THE 0Z
NAM BUFKIT SOUNDINGS LOOK GOOD FOR FREEZING RAIN WITH A WARM LAYER
ABOVE 2KFT...AND BELOW FREEZING TEMPS DOWN TO THE SURFACE. AS
SURFACE TEMPS DROP DUE TO THE FALLING PRECIP AND INCREASING COLD
AIR DAMMING...MOST AREAS WILL SEE AREAS OF LIGHT FREEZING RAIN
FRIDAY EVENING AND OVERNIGHT. THE EXCEPTION TO THIS WILL BE ACROSS
THE LAKE PLAIN AND THE SOUTHERN PART OF THE WYOMING VALLEY WHERE
SURFACE TEMPS WILL BE JUST ABOVE FREEZING. ICE AMOUNTS ARE NOT
EXPECTED TO BE HIGH...WITH MOST LOCATIONS GENERALLY SEEING A TENTH
OF AN INCH OR LESS FRIDAY NIGHT. THE CRITERIA FOR A FREEZING RAIN
ADVISORY IS A TRACE OF ICE SO ADVISORIES WILL LIKELY BE ISSUED FOR
MOST OF THE AREA FOR FRIDAY NIGHT. KEEP IN MIND WITH THE INCREASED
HOLIDAY TRAVEL...IT ONLY TAKES A SMALL AMOUNT OF ICE ON AREA ROADS
TO CAUSE PROBLEMS.
ON SATURDAY THE COLD AIR WILL BE STUBBORN TO LEAVE...ESPECIALLY
AREAS EAST OF 81. CASE IN POINT...THE NAM BUFKIT SOUNDING FOR KRME
NEVER GETS ABOVE FREEZING AT THE SURFACE. IN THIS SITUATION THE
HIGHER RESOLUTION OF THE NAM12 MODEL SEEMED LIKE THE BEST MODEL TO
DEPICT THE COLD AIR BEING TRAPPED NEAR THE SURFACE. FREEZING RAIN
WILL CHANGE TO PLAIN RAIN BY MID MORNING FOR MOST AREAS...WITH
FREEZING RAIN LINGERING ACROSS THE FAR EAST THROUGH AFTERNOON. ON
THE WHOLE QPF AMOUNTS LOOK LOW ACROSS MOST OF THE AREA AS WE GET
DOWNSLOPED IN THE SOUTHEAST FLOW. THIS WILL LIMIT THE ICE
POTENTIAL ACROSS MOST OF THE AREA...WITH TOTAL ICE ACCUMULATIONS
FROM FRIDAY NIGHT THROUGH SATURDAY EXPECTED TO BE A TENTH OF AN
INCH OR LESS FOR MOST OF THE CWA. THE EXCEPTION WILL BE ACROSS THE
EAST WHERE THE COMBINATION OF THE LONGER DURATION (COLDER TEMPS)
AND SOUTHEAST FLOW (UPSLOPE FLOW) MAY PRODUCE ICE AMOUNTS BETWEEN
A QUARTER AND A HALF OF AN INCH.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
XTNDD PD FEATURES A COLD NW FLOW AND SCT LES. ONE FEATURE OF
INTEREST IS A DIGGING WV AND LOW DVLPMT ON MON. AS USUAL...THERE
IS CNSDRBL DFRNCS IN THE TIMING AND LOCATION OF THE SFC LOW IN THE
EURO...GFS AND ENSEMBLE MEAN FCSTS...WITH THE OPERATIONAL GFS MVG
THE SFC LOW CLOSEST TO THE FCST AREA. IN ANY EVENT...ATTM IT
APPEARS THAT THE SYSTEM WILL REALLY ONLY ENHANCES THE ON GOING LES
AS THE DVLPMT OF THE LOW IS REALLY TOO LATE TO OFFER A SIGNIFICANT
WEATHER EVENT TO THE FCST AREA.
HPC GUID WAS LOADED AS A STARTING POINT AND LGTLY ADJUSTED TO THE
LATEST THINKING.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
LL CLDS CAUSING MVFR/IFR CIGS REALLY LOCKED IN OVER CNTRL NY
ATTM...WITH SOME SLOW EROSION AT THE EDGES. MODEL FCST SHOW ENUF
DRYING TO BRK UP THE ST DECK FOR A TIME LATE THIS AFTN AND
EVE...BEFORE MOISTURE RETURNS ARND 06Z. HAVE FCSTD THE IFR/MVFR
CIGS TO CONT THIS AFTN FOR A FEW HRS...FLWD BY A SHRT WINDOW OF
VFR/MVFR CIGS AND FINALLY A RETURN TO IFR AND MVFR CIGS AFT 06Z.
SOME MIXING AHD OF THE BIG LOW MAY HELP RAISE THE CIGS AGAIN AFT
12Z ON THE 25TH. XPCT ALL PCPN FROM THE LOW TO HOLD OFF UNTIL AFT
THE TAF PD.
LGT SELY WINDS THRU THE PD WITH THE WEAK GRADIENT BETWEEN THE SE
CANADA HI AND THE DVLPG PLAINS STORM.
.OUTLOOK...
FRI AFTN...MVFR/IFR CIGS EARLY OTHERWISE VFR.
FRI NGT...MVFR IN MIXED PRECIP.
SATURDAY/SATURDAY NIGHT...IFR POSSIBLE IN ICE/RAIN/SNOW.
SUN/MON/TUE...MVFR WITH AREAS OF LAKE EFFECT SNOW AT NY SITES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...HEDEN
LONG TERM...DGM
AVIATION...DGM
