FXUS61 KBGM 081151
AFDBGM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
651 AM EST TUE DEC 8 2009

.SYNOPSIS...
LAKE EFFECT SNOW WILL AFFECT THE MOHAWK VALLEY AND TUG HILL PLATEAU 
THIS MORNING BEFORE DIMINISHING. A STORM SYSTEM MOVING ACROSS THE 
PLAINS STATES WILL BEGIN TO SPREAD SNOW INTO CENTRAL NEW YORK AND 
NORTHEAST PENNSYLVANIA BY MIDNIGHT. THE SNOW WILL MIX WITH SLEET 
WEDNESDAY MORNING...BEFORE CHANGING TO RAIN BY AFTERNOON. COLD AND 
BLUSTERY CONDITIONS CAN BE EXPECTED BEHIND THIS SYSTEM...WITH 
SCATTERED LAKE EFFECT SNOW SHOWERS ACROSS UPSTATE NEW YORK LINGERING 
THROUGH THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LES CONTS ACRS ONEIDA CNTY EARLY THIS MRNG. BAND HAS INCRSD IN 
INTENSITY FM FLORENCE DOWN INTO ROME WITH WITH CAMDEN WEBCAM SHOWING 
OCNL WHITEOUT CONDS AND LKLY SEVERAL INCHES OF SNOW UP IN NW 
PORTIONS OF THE CNTY ALREADY. BUFKIT SNDGS INDICATE INVERSION AND 
OMEGA RMN FAVORABLE FOR THE NEXT SVRL HRS FOR MODERATE SNOWFALL ACRS 
THESE AREAS. HWVR...BAND IS PROGGED TO WAVER IN ITS LOCATION THRU 
APPROX 10Z AND DOES NOT APPEAR AS IF IT WILL BE PERSISTENT OVR ANY 
ONE LOCATION LONG ENUF TO PRODUCE ADVISORY CRITERIA SNOWS. AFT 
10Z...INVERSION BEGINS TO LOWER AND RESULT IN WEAKENING OF BAND. HV 
ISSUED SPS FOR THE TIME BEING TO HIGHLIGHT DIMINISHED VSBYS AND 
LOCALLY HVY SNOWFALL ACRS ONEIDA CNTY...AND WILL CONT TO MONITOR 
POTENTIAL FOR SHORT-TERM ADVISORY. 

AFT 10Z EXPECT LES TO BEGIN TO WANE AS INVERSION LOWERS. AT THE SAME 
TIME...WINDS BCM MORE NWRLY AND SNOW SHOWERS WILL BE MORE COMMON 
ACRS ONONDAGA/MADISON CNTYS WITH FLURRIES ELSEWHERE ACRS UPSTATE NY. 
EXPECT OVERALL PCPN TO COME TO AN END BY 15Z. 

MEANWHILE UPSTREAM H5 SYSTEM WILL BE ROTATING THRU INTERMOUNTAIN 
REGION AND INTO SRN PLAINS WHERE IT WILL BCM NEGATIVELY TILTED BY 
THIS EVNG. 988MB LOW HAS ALREADY DVLPD OVR NRN ARIZONA WHICH IS 
WELL-DEPICTED BY 00Z GFS. SNOW IS OVERSPREADING CNTRL PLAINS THIS 
MRNG WITH BLIZZARD CONDS EXPECTED TODAY ACRS THE CNTRL U.S. 

BY 00Z SFC LOPRES PROGGED TO MV INTO CNTRL OK WITH WAA ALONG SFC 
BNDRYS MVG INTO OH VLY/PARTS OF THE APPS. THRU THE END OF TODAY...DO 
NOT EXPECT THIS SYSTEM TO HV MUCH OF AN IMPACT ON FA BUT THINGS WILL 
BEGIN TO CHG LATER TONIGHT. 

MOST OF CWA WILL BE PCLDY FOR A GOOD PART OF THE DAY...WITH MID-HIGH 
CLDS INCRSG THRU THE AFTN. HIGHS WILL TOP OUT A LITTLE WARMER THAN 
YESTERDAY...WITH MOST PLACES REACHING INTO THE M/U 30S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
WOUND UP LOW PRESSURE TREKS INTO THE GREAT LKS LATE TONIGHT. AHD OF 
THIS...WARM ADVECTION PCPN WILL KICK IN ACRS WRN/SRN SXNS BTWN 
03Z-06Z THEN OVERSPREAD RMNDR OF CWA AFT 06Z. PROFILES AT THIS POINT 
INDICATE ALL SNOW STARTING OFF. AS USUAL...MODELS HVG A HARD TIME 
HANDLING A POSSIBLE WARM LAYER WITH NAM CLDR THAN GFS. NAM KEEPS AVP 
AT ALL SNOW THRU 12Z BFR MIXING AND THEN CHGNG TO RAIN BY 15Z. 

IN CONTRAST...GFS MIXES AVP OVR BY 09Z WITH ALL RAIN EXPECTED BY 
12Z. REALITY WL LKLY BE SOMEWHERE IN BTWN. STRONG FRCG EXPECTED WITH 
INITIAL SHOT OF SNOW LEADS ME TO LEAN TWD SNOW LONGER THAN WHAT GFS 
IS INDICATING DUE TO DYNAMIC COOLING. HWVR...CANNOT RULE OUT A MIX 
IN THE WYOMING/LACKAWANNA VLYS SHORTLY AFTER ONSET OF PCPN. EVEN THE 
NAM PROFILES INDICATE A FAIRLY ISOTHERMAL SNDG DOWN SOUTH TWD 
DAYBREAK. THUS...WILL PLAN TO SPLIT THE DIFFERENCE BTWN NAM/GFS AND 
MIX FAR SOUTH WITH SN/RA/IP BTWN 06Z-09Z. THIS WL CUT DOWN ON AMNTS 
SOME ACRS THE AREA BUT WILL NOT LOWER RATIO TOO MUCH DUE TO 
UNCERTAINTY.  

LATEST SPC ANALYSIS INDICATING SNOW/LIQUID RATIO FM 10:1 INITIALLY 
THEN MORE TWD 5 TO 8:1 BY 12Z WED. THESE RATIOS WUD INDICATE A GNRL 
3-5 INCH SNOWFALL FM 03Z-12Z WED FM APPROX STEUBEN CNTY DOWN INTO 
POCONOS. 

WARM AIR WILL GRADUALLY WORK ITS WAY INTO CWA WED MRNG. WHILE GFS 
INDICATES A FASTER CHANGEOVER...BOTH MODELS INDICATE A MIX ACRS MOST 
OF THE CWA ARND 15Z...BCMG ALL RAIN DRG THE AFTN. TOTAL ACCUMS LOOK 
TO BE ON THE ORDER OF 3-6 INCHES FM LATE TONIGHT THRU WED MRNG.
WILL LKLY BE ISSUING WINTER WX ADVISORY FOR ENTIRE CWA WITH THIS
PACKAGE.  

DRY AIR MVS IN LATE THIS AFTN WITH ONLY CHC POPS EXPECTED TONIGHT. 
FLOW TURNS SWRLY TONIGHT AND H8 TEMPS DROP BLO -5C WITH GOOD 
POTENTIAL FOR LK EFFECT SETTING UP LATE TONIGHT. HWVR...FLOW WILL 
KEEP STRONGEST PCPN TO NORTH OF CWA THRU 18Z THURSDAY BFR VEERING TO 
MORE WRLY DRG THE AFTN. 

STRONG WINDS BHND SYSTEM EXPECTED WITH GUSTS OF 40-45 MPH NOT OUT OF 
THE QUESTION ACRS THE LK PLAIN LATE WED NIGHT INTO THURSDAY. 

LK EFFECT SNOW WILL PLAGUE NRN SXNS THRU THE END OF THE SHORT TERM 
PD. FLOW WILL WAFFLE BTWN 250-270 WITH NO CLEAR-CUT LOCATION WHERE 
LK BANDS MAY SET UP. HEAVIEST SNOW STILL LOOKS TO BE JUST NORTH OF 
CWA BUT ERIE BAND MAY BE ABLE TO PENETRATE INTO PORTIONS OF THE 
FINGER LKS. LK INSTABILITY/FRCG WILL MOST CERTAINLY BE PRESENT AND 
ACCUMS WILL DEPEND STRICTLY ON FLOW REGIME.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS IN FAIR AGREEMENT WITH ZONAL FLOW FROM THE EASTERN PLAINS
ACROSS TO THE ATLANTIC. WITH THE FLOW ORIGINATING FROM THE ALASKA
REGION...THE AIR WILL BE QUITE CHILLY. 850 RANGE FROM -14C TO -17C
IN THE MODELS. WITH A WESTERLY FLOW...LAKE EFFECT SHOULD BEGIN TO
CRANK UP FOR THE END OF THE WEEK. IT IS TOO EARLY TO PINPOINT
WHERE ANY BANDS WILL SET UP. THE CURRENT GUESS WOULD BE UP IN THE
TUG HILL REGION.

BY SATURDAY NIGHT...A RIDGE WILL BUILD AHEAD OF THE NEXT LOW. THIS
WILL ALLOW TEMPS TO WARM SIGNIFICANTLY. 850 TEMPS WILL RISE TO
AROUND -4C BY 00Z SUNDAY. THIS RIDGE WILL BE VERY SHORT LIVED AS A
STRONG LOW PRESSURE SYSTEM ALOFT RIDE ALONG THE NORTHERN PORTION
OF THE FLOW. THERE IS SOME DISCREPANCY IN THE MODELS AT THIS
POINT. THE GFS HAS TWO SFC LOWS...ONE THAT TRACKS ALONG THE ST
LAWRENCE AND THE OTHER FROM THE OUTER BANKS OF NORTH CAROLINA
NORTHEASTWARDS INTO THE ATLANTIC. THE NORTH LOW WOULD HAVE A
STRONG COLD FRONT ASSOCIATE WITH IT. THIS WOULD QUICKLY PROGRESS
THROUGH THE CWA.

THE ECMWF MAINTAINS THE SINGLE MAIN LOW OFF THE EAST COAST...WITH
SOME WRAP AROUND PRECIP AFFECTING THE CWA. IT DOES HINT AT A
SECONDARY LOW PRESSURE CENTER...BUT FAIRLY WEAK IN THE LATEST
MODEL RUN. THIS HAS WEAK FLOW ACROSS THE CWA AND PERHAPS KEEPS THE
LAKE EFFECT GOING IN THE BEGINNING OF THE WEEK. HAVE LEANED MORE
TOWARDS THIS OPTION ATTM.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
CONDITIONS HAVE BEGUN TO IMPROVE IN VARIOUS LOCATIONS. THIS IS
EXPECTED TO BE TEMPORARY AND CEILINGS WILL MOST LIKELY BOUNCE
BETWEEN IFR AND VFR TODAY AS BANDS OF LAKE EFFECT MOVE INTO SOME
AREAS AND A LOW PRESSURE SYSTEM APPROACHES. LATER TONIGHT...EXPECT
SNOW TO MOVE INTO THE REGION. THIS WILL BRING IFR TO LIFR
CONDITIONS DUE TO CEILINGS AND VIS. WINDS MAY ALSO BECOME GUSTY
WITH THE FRONTAL PASSAGE. THIS LOOK NOT TO BE SO MUCH A COLD
FRONTAL PASSAGE AS AN OCCLUDED FRONT. THIS WILL LIKELY KEEP WINDS
FROM GUSTING TO EXTREME WITH THIS SYSTEM. HOWEVER...THERE MAY
STILL BE GUSTS OF 35 TO 40KTS...ESPECIALLY ALONG THE MOHAWK
VALLEY. FURTHER SOUTH...THE WINDS WILL NOT BE AS STRONG...BUT
GUSTS MAY STILL REACH UP TO AROUND 30KTS. THE FRONTAL PASSAGE LOOKS TO
BE BETWEEN 12 AND 18Z WEDNESDAY ACROSS THE REGION.

OUTLOOK...
 
TUE NGT...MVFR/IFR LATE IN SNOW. MOVING SW TO NE STARTING AT ELM
AND AVP BY MIDNIGHT TO RME BY 08Z. 

WED...MVFR/IFR IN SNOW AND MIXED PRECIP...CHGNG TO ALL RAIN BY
AFTN.

WED NGT THRU SATURDAY...OCCASIONAL MVFR/IFR IN LAKE EFFECT SNOW
SHOWERS PRIMARILY KRME/KSYR.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO NOON EST 
     WEDNESDAY FOR PAZ038>040-043-044-047-048-072.
NY...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO NOON EST 
     WEDNESDAY FOR NYZ009-015>018-022>025-036-037-044>046-
     055>057-062.

&&

$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...PVN
LONG TERM...10
AVIATION...10