FXUS61 KBGM 112325
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
625 PM EST FRI DEC 11 2009
.SYNOPSIS...
SIGNIFICANT LAKE EFFECT SNOW WILL OCCUR ACROSS ONEIDA COUNTY
TONIGHT WITH FLURRIES AND BRIEF SQUALLS ELSEWHERE. NEAR TO
SLIGHTLY BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH SATURDAY.
LAKE EFFECT SNOWS WILL DIMINISH SATURDAY AFTERNOON...WITH THE
NEXT CHANCE FOR PRECIPITATION ON SUNDAY...IN THE FORM OF RAIN OR
SNOW.
&&
.NEAR TERM /THROUGH SATURDAY/...
UPDATED AS OF 545 PM...
LAKE ERIE BAND NOW EXTENDS ACROSS MOST OF NY'S SOUTHERN TIER...AND
HAS INTENSIFIED A BIT EARLY THIS EVENING. THIS IS LIKELY IN
RESPONSE TO LOSS OF BOUNDARY LAYER HEATING...ALLOWING ANY LOW-
LEVEL TERRESTRIAL INSTABILITY TO VANISH...AND A STRONG
CONSOLIDATED BAND TO TAKE OVER. AT ANY RATE...WITH ONLY A GRADUAL
VEERING PATTERN OF THE WINDS THIS EVENING (260-270 AROUND TO
270-280 LATER THIS EVENING)...THIS BAND SHOULD STAY WELL IN TACT
FOR THE FIRST PART OF THE EVENING...AT LEAST. WE UPDATED THE
FORECAST IN THE SOUTHERN TIER NY COUNTIES TO ACCOUNT FOR THESE
SQUALLS...AND ADD A GENERAL 1-3" ACCUMULATION...WHERE THE BAND IS
MOST PERSISTENT. WE'VE ALSO ISSUED A SHORT-TERM SPECIAL WEATHER STATEMENT.
LOCAL WRF...SUPERENSEMBLE...AND NAM12 SOLUTIONS ALL WEAKEN THE BAND
LATER THIS EVENING...AS IT DROPS FURTHER SOUTH. GIVEN ONLY A SMALL
CHANGE IN UPSTREAM FETCH...AM SOMEWHAT SKEPTICAL OF THIS HAPPENING
SO QUICKLY. FOR NOW...THOUGH...WILL MAINTAIN FORECAST CONSISTENCY
AND CONTINUE TO MONITOR NEAR-TERM TRENDS.
THE LAKE ONTARIO BAND REMAINS STRONG...THROUGH NORTHERN ONEIDA AS
OF THIS WRITING. LITTLE CHANGE IN FORECAST REASONING CONCERNING
THE EVOLUTION OF THIS BAND...SO PLEASE REFER TO EARLIER DISCUSSION
BELOW FOR SPECIFICS.
PREVIOUS DISCUSSION...
AS OF 424 PM...FIRST SIGNIFICANT LAKE EFFECT EVENT OF
THE SEASON CONTINUES WITH COLD AND BLUSTERY WEATHER ELSEWHERE.
FIRST OFF THE LAKE EFFECT. THE BAND HAS REMAINED FAIRLY STATIONARY
TODAY WITH A SLIGHT SOUTHWARD SHIFT...AS THE MODELS HAVE BEEN
INDICATING. THE NAM12 CONTINUES TO BE THE MODEL OF CHOICE AS IT
HAS HANDLED THE SITUATION THE BEST. OUR LOCAL WRF MODEL IS ALSO
DOING A DECENT JOB BUT HAS THE BAND A BIT TOO FAR SOUTH...MOVING
IT INTO NORTHERN ONONDAGA/MADISON COUNTIES OVERNIGHT. WILL USE A
BLEND BETWEEN THE TWO...USING THE NAM12 FOR BAND PLACEMENT...AND
THE LOCAL WRF TO PICK UP ON THE INTENSITY OF THE BAND.
SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR WILL BE COMMON WITH UP TO
3 INCHES POSSIBLE IN THE HEART OF THE BAND. LOOKING AT THE KRME
BUFKIT SOUNDING...WE SHOULD HAVE A HUGE FLUFF FACTOR WITH VERY
STRONG OMEGAS INTERSECTING THE SNOW GROWTH REGION. REALLY A TEXT
BOOK EXAMPLE OF GREAT SNOW FLAKE PRODUCTION. EVENTUALLY BY 06Z OUR
INVERSION WHICH STARTS OUT AROUND 700 MB...BEGINS TO LOWER. THE
BAND WILL STILL BE IMPRESSIVE...BUT RATES WILL DIE DOWN A BIT.
WITH THAT IN MIND THE HEAVIEST SQUALLS WILL BE FROM NOW THROUGH
MIDNIGHT.
AS FAR AS BAND PLACEMENT GOES THE BAND WILL REMAIN NEARLY
STATIONARY THROUGH 0Z. BETWEEN 0Z AND 03Z THE BAND DRIFTS SLOWLY
SOUTH A BIT...AS WINDS TURN TOWARD 280/285. BETWEEN 03Z AND 12Z
THE BAND WILL CONTINUE TO DRIFT JUST A BIT TO THE
SOUTH...REMAINING ACROSS THE CENTRAL AND NORTHERN PART OF ONEIDA
COUNTY. WITH THE BAND BEING MOST PERSISTENT ACROSS THE NORTHERN
PART OF THE COUNTY...MORE THAN A FOOT OF SNOW IS LIKELY HERE WITH
ISOLATED TOTALS NEAR 20 INCHES. FARTHER TO TH SOUTH ITS MUCH MORE
COMPLICATED WITH SUCH A SHARP GRADIENT FROM SQUALLS TO NOTHING
EXPECTED. THINKING THAT 5 TO 10 INCHES IS POSSIBLE ACROSS THE
CENTRAL PART OF ONEIDA COUNTY FROM BLOSSVALE TO FLOYD TO HOLLAND
PATENT...WITH A DUSTING TO AN INCH NEAR THE CITY OF UTICA. THE
LAKE EFFECT SNOW WARNING FOR THE SOUTHERN PART OF ONEIDA COUNTY
WAS ISSUED FOR THE IMPACT TO THE CENTRAL PART OF THE COUNTY...IN
THE AREAS MENTIONED ABOVE. WE ARE NOT EXPECTING AN IMPACT NEAR THE
THRUWAY.
SATURDAY...LAKE BAND REMAINS ACROSS ONEIDA COUNTY IN THE MORNING
BEFORE SLOWLY WEAKENING BY EARLY AFTERNOON AS THE INVERSION
CONTINUES TO CRASH AND WE ADVECT IN MUCH DRIER AIR.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
SHRT WV APRCHS THE AREA SAT NGT AND EXITS EARLY MON. FCST AREA
UNDER A FLAT RDG AND WITH WRMG AHD OF THE LOW PCPN TYPE IN
QUESTION. OPERATIONAL NAM REALLY THE WRMST OF THE MODELS WITH A
WIDESPREAD LGT RAIN EVENT FOR THE ENTIRE FCST AREA. ON THE COLD
SIDE IS THE 00Z ECMWF WITH A WIDESPREAD SNOW EVENT...EVEN IN NE
PA...WITH SOME CONCERNING QPF AMTS. IN THE MIDDLE FALL THE GFS
AND SREF MEAN. AS USUAL...FELT THE SAFEST BET ATTM WLD BE TO GO
WITH THE AVG OF SOLNS WHICH IS NEAR THE SREF AND GFS. THIS WLD
BRING SOME LGT SNOW FLWD BY MIXED PCPN TO MUCH OF THE FCST AREA.
ONLY XCPTN MADE WAS FOR THE XTRM NORTH WHERE AVGS GIVE ALL SNOW
FOR THE EVEN. DECIDED NOT TO BUY THE HEAVIER EURO AMTS AND WITH WITH
GNRLY LGT QPF AND SNOW ACCUMS.
NAM USES IT/S TIGHTER BAROCLINIC ZONE TO DEEPEN THE SFC LOW MORE AS
IT RCHS THE CST. THIS ALLOWS THE PCPN TO LINGER MUCH OF SUN NGT
AND EVEN INTO EARLY MON. ONCE AGAIN WENT MORE TWRD THE MEAN SOLN
AND TAPER THE PCPN AFTER DARK SUN...AND KEEP THE FCST AREA DRY ON
MON WITH WEAK RDGG.
ATTM...DOES NOT LOOK LIKE A FLAG-ABLE EVENT BUT WILL KEEP A
MENTION IN THE HWO JUST IN CASE THE ECMWF HAPPENS TO BE ONTO
SOMETHING. IN THAT ECMWF SCENARIO...SEVERAL INCHES OF SNOW WOULD
FALL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODEL GUIDANCE IN REASONABLY GOOD AGREEMENT THAT THE START OF THE
PERIOD WILL BE FAIRLY MILD...AHEAD OF A STRONG COLD FRONT.
SCATTERED RAIN AND SNOW SHOWERS LOOK LIKE THEY'LL PREVAIL MONDAY
NIGHT INTO TUESDAY.
ONCE THE AFOREMENTIONED FRONT CROSSES THE AREA LATER
TUESDAY...MUCH COLDER CONDITIONS WILL RETURN FOR THE BALANCE OF
THE WEEK...ALONG WITH A DAILY CHANCE FOR SNOW SHOWERS OR
FLURRIES...WITH A NORTH TO NORTHWESTERLY FLOW PATTERN.
&&
.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
BANDS OF LAKE EFFECT SNOW OFF OF ONTARIO AND ERIE WILL CAUSE
RESTRICTIONS THROUGH THE OVERNIGHT HOURS. CONDITIONS SHOULD BE
RAPIDLY IMPROVING AT KITH AS THE BAND DRIFTS SOUTH OF THE AIRPORT,
WHILE CONDITIONS WILL DETERIORATE AT KBGM AS THE BAND ARRIVES
WITHIN 2 HOURS. THIS WILL LEAD TO LOW MVFR CEILINGS AND IFR
VISIBILITIES.
A STRONGER BAND DRIFTING SOUTH THROUGH ONEIDA COUNTY WILL BRING
IFR CONDITIONS TO THE KRME TERMINAL BETWEEN 2Z AND 4Z. THE SNOW
BAND WILL AFFECT THE TERMINAL THROUGH ABOUT 8Z-11Z, THEN BEGIN TO
RECEDE NORTHWARD.
ALL TERMINALS WILL BE DEALING WITH GUSTY WINDS THIS MORNING. WIND
GUSTS OF 30-35 KNOTS ARE POSSIBLE AT KSYR THROUGH MIDNIGHT.
OUTLOOK...
FRIDAY THROUGH SATURDAY...HIGHLY VARIABLE CIGS/VSBYS AT KSYR-KRME
WITH LAKE EFFECT SNOW SHOWERS IN THE VICINITY. VFR WITH SCT-BKN
CIGS AND A CHC OF MVFR CIGS KITH-KELM-KBGM-KAVP.
SUNDAY...VFR.
MONDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW WARNING UNTIL 10 AM EST SATURDAY FOR NYZ037.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST SATURDAY FOR NYZ009.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN/MLJ
SHORT TERM...DGM
LONG TERM...MLJ
AVIATION...DJP
