FXUS61 KBGM 080825
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
325 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 THURSDAY NIGHT/...
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 THROUGH MONDAY/...
ALL GUIDANCE SUGGESTS A COLD WESTERLY FLOW PATTERN WILL START THIS
PERIOD (THURSDAY NIGHT AND FRIDAY). LAKE-EFFECT SNOWS WILL BE
ONGOING...WITH THE PROGGED SURFACE-850 MB FLOW TRAJECTORIES
SEEMINGLY PINPOINTING NORTHERN ONEIDA...OR PERHAPS NORTH OF OUR
FORECAST AREA (OSWEGO/LEWIS/JEFFERSON)...FOR THE MOST PERSISTENT
SNOW SHOWERS/SQUALLS. ONLY A FEW FLURRIES ANTICIPATED ELSEWHERE.
STILL A FAIR AMOUNT OF UNCERTAINTY THIS WEEKEND...WITH MOST MODEL
GUIDANCE SHOWING A SURFACE WAVE DEVELOPING OVER THE GULF OF MEXICO
BY SATURDAY...THEN MOVING NORTHEAST TOWARDS THE MID-ATLANTIC
COAST BY SUNDAY. PRESENT THINKING IS THAT MOST OF THE PRECIPITATION...
SPECIFICALLY FROM THIS SYSTEM...WILL STAY SOUTH AND EAST OF OUR
FORECAST AREA. SINCE THIS IS STILL SEVERAL DAYS AWAY...THOUGH...IT
WILL BEAR WATCHING.
AT ANY RATE...ONCE THIS SYSTEM PROGRESSES OFF TO OUR NORTHEAST
LATER SUNDAY AND MONDAY...LAKE-EFFECT ACTIVITY IN ITS WAKE LOOKS
LIMITED FROM THIS EARLY VANTAGE POINT...WITH HIGH PRESSURE QUICKLY
BUILDING IN.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
IFR CONDITIONS AT SYR AND RME WILL CONTINUE FOR 2 TO 4 HOURS THIS
EVENING. A 260 LL FLOW HAS BROUGHT ADDITIONAL MOISTURE OFF OF LAKE
ERIE TO THESE SITES. THIS IS ENHANCING THE SATURATED LOW LAYERS
FROM THE WEAK SYNOPTIC SYSTEM. THE FLOW WILL SHIFT TO NW LATE THIS
EVENING BRINGING SNOW SHOWERS OFF OF LAKE ONTARIO LATE TONIGHT TO
RME AND SYR. VSBYS COULD FALL TO IFR LATE TONIGHT. AROUND MIDNIGHT
THERE WILL BE A BREAK IN MVFR AND IFR.
OTHER SITES WILL BE MOSTLY VFR. THE OTHER NY SITES COULD FALL TO
MVFR AS THE FLOW SHIFTS SOUTH PUSHING THE LAKE ERIE BAND THROUGH.
LATE TONIGHT ITH AND BGM COULD HAVE SOME MVFR CONDITIONS WITH
FINGER LAKE SNOW.
THE FLOW WILL WEAKEN AND SHIFT TO SE STARTING MIDDAY ENDING THE
LAKE EFFECT.
S TO SW WINDS AT 5 KTS OR LESS SHIFTING TO W LATE TONIGHT THEN NW
TUE MORNING. LATE TUE EASTERLY WINDS AT 5 KTS OR LESS.
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...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...PVN
LONG TERM...MLJ
AVIATION...TAC
