FXUS61 KBUF 260448
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1148 PM EST WED NOV 25 2009
.SYNOPSIS...
A SOUTHERLY FLOW OF MILD AND RELATIVELY MOIST AIR WILL CONTINUE
ACROSS WESTERN AND CENTRAL NEW YORK THROUGH THANKSGIVING DAY. THERE
WILL BE THE RISK OF A FEW SHOWERS NOW AND THEN...BUT IT
WILL BE DRY MOST OF THE TIME. COMPLEX LOW PRESSURE WILL DEVELOP OVER
SOUTHERN ONTARIO AND LAKE ERIE THURSDAY NIGHT AND DEEPEN AS IT MOVES
EAST AND OFF THE NEW ENGLAND COAST BY EARLY SATURDAY. THIS WILL
RESULT IN AN INCREASING CHANCE OF RAIN THANKSGIVING NIGHT WHICH MAY
CHANGE TO WET SNOW OVER HIGHER ELEVATIONS BY FRIDAY MORNING. COLDER
AIR WILL FOLLOW FRIDAY AND SATURDAY WITH DIMINISHING PRECIPITATION.
&&
.NEAR TERM /THROUGH THURSDAY/...
A SURFACE LOW OVER WESTERN ONTARIO WILL DRAW A WEAKENING COLD FRONT
ACROSS THE WESTERN ZONES THIS EVENING...WASHING IT OUT OVERNIGHT.
SHOWERS ALONG AND AHEAD OF THE FRONT WILL CROSS WESTERN AND NORTHERN
NEW YORK...WITH LESSER CHANCE OF SHOWERS OVER THE FINGER LAKES AND
CENTRAL NY. THERE WILL BE A BREAK IN THE RAIN CHANCE DURING THE
OVERNIGHT HOURS WITH SOME DRIZZLE STILL POSSIBLE FROM THE THICK
OVERCAST SKIES. TEMPS TONIGHT WILL FALL TO LOWS IN THE LOWER TO MID
40S...TO THE UPPER 30S IN THE COLDER VALLEYS OF THE SOUTHERN TIER.
THE SURFACE LOW WILL REMAIN OVER ONTARIO TO JAMES BAY AS ANOTHER
UPPER LEVEL FEATURE REINTENSIFIES THE COLD POOL OVER THE CENTRAL
GREAT LAKES AND MIDWESTERN STATES. THIS NEXT COLD FRONT WILL THEN
APPROACH NEW YORK STATE ON THURSDAY WITH SHOWERS REDEVELOPING OVER
THE WESTERN COUNTIES DURING THE AFTERNOON. IT APPEARS THAT THE BULK
OF THE UPPER LEVEL ENERGY ASSOCIATED WITH THIS MIDWESTERN TROUGH
WILL UNDERCUT THE FORECAST AREA AND PASS OVER PENNSYLVANIA LATER ON
THURSDAY NIGHT...YIELDING LIKELY POPS OVER THE WESTERN EDGE OF THE
STATE DURING THURSDAY AFTERNOON...AND KEEPING ONLY SLIGHT CHANCE
POPS FROM THE FINGER LAKES TO THE NORTH COUNTRY. HIGHS ON THURSDAY
WILL BE LIMITED BY THE THICK CLOUD COVER AND THE SLOW PASSAGE OF THE
COLD FRONT WITH HIGHS IN THE 40S FOR MUCH OF THE FORECAST
AREA...SOME TEMPS NEAR 50 OVER THE NORTH COUNTRY WHERE THE COLD
FRONT WILL ARRIVE AFTER SUNSET.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
THIS PERIOD WILL BEGINS WITH A SHARP UPPER NORTH-SOUTH ORIENTED TROF
MOVING EAST FROM MICHIGAN WHICH EVENTUALLY CLOSES OFF INTO AN UPPER
LOW OVER PA WHICH SPAWNS A DEEPENING COASTAL LOW OFF NEW JERSEY
FRIDAY. MOST OF OUR AREA WILL BE TOO FAR NORTH AND WEST TO BE
AFFECTED MUCH BY THIS SYSTEM...LYING IN SORT OF A "COL" BETWEEN IT
AND A WEAKENING UPPER FEATURE LIFTING ACROSS ONTARIO TO OUR NORTH.
WE SHOULD ALL GET AN INITIAL SHOT OF RAIN THURS EVE...WHICH
DIMINISHES AND DROPS SOUTHEAST DURING THE NIGHT. ENOUGH COLD AIR WILL
FILTER INTO THE SYSTEM AS IT DEEPENS TO OUR EAST TO CHANGE THE RAIN
TO WET SNOW OVER HIGHER ELEVS OF SRN TIER LATER AT NIGHT...BUT IT IS
QUESTIONABLE HOW MUCH QPF WILL BE LEFT. IN FACT...NAM AND EC MODELS
SHOW VIRTUALLY NO QPF FROM BUF-ROC AFTER 06Z FRIDAY. WILL THEREFORE
HAVE LIKELY POPS FOR AWHILE THURS EVE...TAPERING TO CHC FROM NW TO
SE AS THE NIGHT WEARS ON.
FRIDAY WILL BE CHILLY AND BLUSTERY WITH INCREASING NW WINDS AS LOW
DEEPENS OFF NEW ENGLAND...BUT QPF WILL BE MINOR. WILL LEAVE CHC
POPS EVERYWHERE...BUT AMTS MINIMAL...RAIN/WET SNOW MIX...ESP SRN
TIER. WE WILL EVENTUALLY GET SOME UPSLOPE ENHANCEMENT SE OF THE
LAKES LATER FRI AND FRI NT...BUT 850 MB TEMPS OF -3C TO -5C OR SO
STILL MARGINAL FOR P-TYPE...SO WE ANYTHING SHOULD REMAIN MOSTLY
LIQUID AT LOWER ELEVS BUT MINOR SNOW ACCUMS PSBL FRI NT AT HIGHER
ELEVS OF SRN TIER AND POSSIBLY TUG HILL.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MODELS PULL SYSTEM EASTWARD QUICKLY ON SATURDAY BUT WILL MAINTAIN
CHC POPS SE OF THE LAKES FOR AWHILE DUE TO UPSLOPE. MAINLY DRY
ELSEWHERE SAT BUT CHILLY WITH MAXES IN L40S AS 850MB TROF (-5C)
SWINGS THROUGH.
SUNDAY LOOKS PLEASANT AS RIDGING BUILDS IN AT ALL LEVELS. 850 MB
TEMPS SOAR TO +5C WHICH WOULD SUPPORT NR 50 WITH ANY SUN...ALWAYS A
QUESTION THIS TIME OF YEAR...BUT A DECENT DAY NONETHELESS. NEXT
SYSTEM DEEPENS OVER CENTRAL STATES SUN NT AND SWEEPS A COLD FRONT
ACROSS THE AREA MONDAY. EC AND GFS MODELS IN GOOD AGREEMENT AND ARE
6-12 HRS FASTER THAN PREVIOUS RUNS SO WILL BRING CHC POPS IN LATER
SUN NT AND BROADBRUSH 40 POPS EVERYWHERE MONDAY. TEMPS WILL FALL
IN AFTERNOON WITH PSBL END AS WET SNOW. BRIEF COLD SHOT MON NT AND
TUES WITH 850 MB TEMPS DOWN TO -10C OR SO...BUT NNW FLOW NOT VERY
CONDUCIVE TO LK EFF...WILL CARRY LOW CHC POPS SE OF LAKES MON NT.
FURTHER OUT...TUES NT AND WED LOOK TRANQUIL AT THIS POINT BUT
ANOTHER UPPER LOW DROPS INTO WESTERN LAKES WHICH MAY PORTEND A
WINTRY FINISH TO NEXT WEEK. STAY TUNED.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A VERY MOIST SOUTHWESTERLY FLOW AROUND A NEARLY STATIONARY UPPER
GREAT LAKES LOW WILL KEEP PLENTY OF LOW CLOUDS ACROSS THE REGION
OVERNIGHT. THERE WILL BE A FEW SHOWERS AROUND AS WELL...BUT THE
MAJORITY OF THE OVERNIGHT SHOULD BE PCPN FREE. DURING THE COURSE OF
THE NIGHT...VFR CIGS WILL LOWER TO MVFR.
THE RELATIVELY LOW CIGS ARE EXPECTED TO HOLD IN PLACE THROUGHOUT THE
DAY THURSDAY...RANGING FROM 2500 TO 3500 AT MOST TAF SITES.
AN APPROACHING SHORTWAVE WILL THEN SPRED SHOWERS ACROSS MUCH OF
WESTERN AND NORTH CENTRAL NEW YORK THURSDAY NIGHT...KEEPING MVFR
CONDITIONS IN PLACE. IFR CIGS WILL BE POSSIBLE TOWARDS FRIDAY
MORNING.
OUTLOOK...
FRIDAY...MVFR/IFR WITH RAIN LIKELY...MIXING WITH SNOW ACROSS THE
SOUTHERN TIER.
SATURDAY...VFR/MVFR. A CHANCE OF RAIN/SNOW SHWRS MAINLY E-SE OF THE
LAKES.
SUNDAY...VFR.
MONDAY...IFR IN LOW CLOUDS AND RAIN.
&&
.MARINE...
SOUTHWEST WINDS WILL INCREASE AHEAD OF AN APPROACHING LOW PUSHING INTO
THE GREAT LAKES TONIGHT AND SMALL CRAFT ADVISORIES HAVE BEEN ISSUED
FROM MIDNIGHT TO 6 AM THURSDAY FOR THE EASTERN LAKE ERIE WATERS
WHERE WAVE HEIGHTS APPROACHING 5 FEET ARE POSSIBLE.
WINDS WILL LIGHTEN UP THURSDAY AFTERNOON AND NIGHT AS NEW LOW
PRESSURE ORGANIZES TO OUR SOUTH AND EAST...BUT STRENGTHEN MARKEDLY
FRIDAY AND FRIDAY NIGHT WITH BRISK NORTHWESTERLIES AS THE LOW
DEEPENS WHILE MOVING OFF THE NEW ENGLAND COAST.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR LEZ040-041.
&&
$$
SYNOPSIS...SFM
NEAR TERM...WCH
SHORT TERM...SFM
LONG TERM...SFM
AVIATION...RSH
MARINE...SFM/WCH
