FXUS61 KBUF 112046
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
346 PM EST FRI DEC 11 2009
.SYNOPSIS...
LOCALLY HEAVY LAKE EFFECT SNOW WILL CONTINUE IN THE SNOWBELTS EAST
OF THE LAKES TONIGHT BEFORE ENDING ON SATURDAY MORNING EAST OF LAKE
ERIE AND BY SATURDAY EVENING EAST OF LAKE ONTARIO. ELSEWHERE MAINLY
DRY CONDITIONS WILL CONTINUE THROUGH SATURDAY NIGHT AS A RIDGE OF
HIGH PRESSURE BUILDS OVER THE LOWER LAKES. A WEAK AREA OF LOW
PRESSURE WILL MOVE THROUGH THE GREAT LAKES REGION SUNDAY AND BRING
THE NEXT CHANCE OF PRECIPITATION ALONG WITH WARMER TEMPERATURES. THE
WARM TEMPERATURES WILL LAST THROUGH THE FIRST FEW DAYS OF NEXT WEEK
BEFORE ANOTHER SURGE OF COLD AIR ARRIVES BY WEDNESDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
THIS PERIOD WILL FINALLY SEE THE END TO THE LAKE EFFECT SNOWS ACROSS
THE REGION. DEEP LOW PRESSURE OVER THE CANADIAN MARITIMES THIS
AFTERNOON WILL LIFT OUT INTO THE NORTHERN ATLANTIC TONIGHT...WHILE
HIGH PRESSURE OVER THE TENNESSEE VALLEY RIDGES NORTHEAST INTO THE
OHIO VALLEY. A BRISK WESTERLY FLOW OF ARCTIC AIR WILL CONTINUE
ACROSS NEW YORK STATE IN BETWEEN THESE TWO SYSTEMS. THIS WILL
CONTINUE TO SUPPORT HEAVY LAKE EFFECT SNOWS EAST OF THE LAKES
TONIGHT.
LAKE EFFECT SNOWS OFF LAKE ERIE...RADAR IMAGERY THIS AFTERNOON
SHOWING ACTIVITY HAS BECOME A BIT MORE CELLAR WITH DAYTIME
HEATING. THIS WILL BE ONLY TEMPORARY AND ONCE THE HEATING IS GONE
THE LAKE PLUME WILL RE-INTENSIFY. LOW LEVEL STEERING FLOW WILL
REMAIN ALMOST DUE WESTERLY FLOW...FOCUSING THE MOST INTENSE LAKE
SNOWS ALONG THE CHAUTAUQUA RIDGE AND FAR SOUTHERN PORTIONS OF
SOUTHERN ERIE AND SOUTHERN WYOMING COUNTIES. ACTIVITY DID NUDGE A
LITTLE TO THE NORTH THIS AFTERNOON NEARING THE BUFFALO SOUTHTOWNS
AS THE FLOW BACKED JUST A BIT AHEAD OF A WEAK MID LEVEL SHORT
WAVE. THIS SHORT WAVE WILL PUSH AWAY FROM THE AREA EARLY TONIGHT
ALLOWING THE STEERING WINDS TO VEERING TO A MORE 280 DEGREE FLOW
FOR MUCH OF THE NIGHT. THIS WILL ALLOW THE MOST INTENSE LAKE SNOWS
TO SHIFT A LITTLE FARTHER TO THE SOUTH WITH NEARLY ALL OF THE LAKE
ACTIVITY CONFINED TO CHAUTAUQUA AND CATTARAUGUS COUNTIES...ALTHOUGH
SOME NORTHERN OSCILLATION IS NOT OUT OF THE QUESTION. THIS BAND
WILL ALSO EXTEND EAST INTO WESTERN PORTIONS OF ALLEGANY COUNTY.
CURRENT RADAR ESTIMATES SHOW SNOWFALL RATES PEAKING AT 1" PER HOUR
WITHIN THE HEAVIEST PORTIONS OF THE LAKE ERIE LAKE SNOWS. WITH THE
INTENSIFICATION EXPECTED TONIGHT WOULD NOT BE SURPRISED TO SEE
SNOWFALL RATES PEAK AT 2" PER HOUR FOR A BRIEF PERIOD...ALLOWING
FOR ADDITIONAL ACCUMULATIONS OF 5 TO 10 INCHES WITHIN THE MOST
PERSISTENT SNOWS. LAKE EFFECT SNOW WARNINGS WILL REMAIN INTACT FOR
SOUTHERN ERIE...WYOMING...CHAUTAUQUA AND CATTARAUGUS COUNTIES. A
LAKE AFFECT SNOW ADVISORY WILL REMAIN FOR ALLEGANY COUNTY.
THE LAKE SNOWS WILL BEGIN TO LET UP AFTER MIDNIGHT TONIGHT AS
RIDGING BEGINS BUILDING INTO THE AREA ALONG WITH A DROPPING
SUBSIDENCE INVERSION. ANY LINGERING ACTIVITY WILL END DURING
SATURDAY MORNING AS THE CAP CONTINUES TO LOWER. THERE COULD BE A
SEVERAL HOUR PERIOD WHEN THE LINGERING LAKE BAND LIFTS NORTHWARD
INTO THE BUFFALO METRO AREA IN A WEAKENING STATE AS THE LOW LEVEL
FLOW BACKS TO SOUTHWEST.
MEANWHILE OFF OF LAKE ONTARIO...AN INTENSE SINGLE LAKE EFFECT SNOW
CONTINUES ACROSS FAR SOUTHERN JEFFERSON...NORTHERN OSWEGO...AND MUCH
OF LEWIS COUNTIES...WITH RADAR-ESTIMATED SNOWFALL RATES OF 3 TO 5"
PER HOUR COMMONPLACE ACROSS TUG HILL PLATEAU. THIS BAND SHOULD STAY
PRETTY MUCH IN PLACE THROUGH EARLY TONIGHT...ALTHOUGH IT MAY LIFT
SLIGHTLY NORTHWARD FOR A WHILE...AS THE MID LEVEL WAVE PASSES.
THE BAND WILL SETTLE BACK SOUTH BEHIND THE WAVE AND THEN WILL DROP
A LITTLE FARTHER TO THE SOUTH OVERNIGHT AND SATURDAY MORNING AS
THE STEERING FLOW VEERS TO AROUND 280 DEGREES. THE SOUTHERN EDGE
OF THE LAKE PLUME COULD SHIFT AS FAR SOUTH AS NORTHERN WAYNE AND
NORTHERN CAYUGA COUNTIES AND LATER SHIFTS MAY NEED TO MONITOR
THIS SCENARIO. FOR NOW WILL SUGGEST 2 TO 4 INCH AMOUNTS IN THESE
AREAS. DUE TO THE FULL FETCH OF THE LAKE REALIZED FELL THAT
ADDITIONAL AMOUNTS OF 1 TO 2 FEET WILL BE LIKELY ACROSS THE TUG
HILL TONIGHT THROUGH SATURDAY MORNING. LAKE EFFECT SNOW WARNINGS
WILL REMAIN FOR THIS AREA AS WELL.
WINDS WILL NOT BE AS STRONG AS THEY HAVE BEEN OVER THE PAST 36 PLUS
HOURS...BUT WINDY CONDITIONS WILL STILL PERSIST THROUGH AT LEAST THE
FIRST HALF OF THE NIGHT. THE WINDS WILL STILL HAVE AN IMPACT ON THE
FORECAST EARLY TONIGHT IN THE FORM OF EXTENSIVE BLOWING AND DRIFTING
SNOW IN THE LAKE EFFECT AREAS...WHICH WILL AGAIN RESULT IN DANGEROUS
NEAR WHITEOUT CONDITIONS AT TIMES. SOME BLOWING AND DRIFTING SNOW
WILL ALSO CONTINUE IN AREAS THAT RECEIVED THE HEAVIER LAKE SNOWS
YESTERDAY...THOUGH THIS SHOULD NOT BE QUITE AS BAD AS WITHIN THE
LAKE SNOWS THEMSELVES.
MINIMUM TEMPERATURES TONIGHT FALLING INTO THE TEENS AND COMBINED
WITH THE WINDS WILL CREATE WIND CHILLS FROM ZERO TO NEAR 10 BELOW
AT TIMES.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AT THE START OF THE PERIOD A RIDGE OF HIGH PRESSURE WILL BE CROSSING
THE LOWER LAKES. TEMPERATURES ALOFT WILL BE WARM ENOUGH TO END LAKE
EFFECT OFF LAKE ERIE. OFF LAKE ONTARIO...850MB TEMPS ARE STILL
AROUND -8C AT 00Z SUNDAY. THIS MAY BE COLD ENOUGH TO STILL SUPPORT
SOME VERY LIMITED LAKE RESPONSE...ALTHOUGH ANTICYCLONIC CURVATURE
AND A LOWERING SUBSIDENCE INVERSION SHOULD KEEP THIS ACTIVITY VERY
LIGHT. WILL CARRY CHANCE POPS INTO THE EVENING EAST OF THE LAKE
BEFORE ENDING BY MIDNIGHT AS THE AIRMASS CONTINUES TO MODERATE.
THE NEXT SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW WILL MOVE THROUGH
THE CENTRAL LAKES ON SUNDAY. THIS SYSTEM IS OF PACIFIC ORIGIN...WITH
THE AIRMASS QUICKLY MODERATING AHEAD OF THE SYSTEM. PREFER THE
WARMER NAM PROFILES THAT WARM 850MB TEMPS WELL ABOVE FREEZING ON
SUNDAY GIVEN THE PATTERN RECOGNITION OF A LOW GOING UP TO OUR WEST.
AT THE SAME TIME...SOUTHERLY DOWNSLOPE WINDS WILL ALSO ALLOW THE
BOUNDARY LAYER TO QUICKLY WARM ACROSS THE LOWER ELEVATIONS OF THE
LAKE PLAIN. THIS SHOULD ALLOW MOST OF THE EXPECTED PRECIP TO FALL AS
RAIN ON SUNDAY ACROSS THE LOWER ELEVATIONS. ACROSS THE INTERIOR
SOUTHERN TIER COLD AIR MAY REMAIN TRAPPED IN THE INTERIOR VALLEYS
LONG ENOUGH TO ALLOW PRECIP TO START AS SOME FREEZING RAIN AND
PERHAPS A LITTLE SLEET OR SNOW IF PRECIP ARRIVES EARLY ENOUGH. THIS
SHOULD QUICKLY CHANGE TO RAIN BY LATE MORNING AS THE COLD AIR IS
SCOURED OUT. MAY SEE A SIMILAR TREND EAST OF LAKE ONTARIO WHERE
PRECIP MAY BRIEFLY START AS A LITTLE FREEZING RAIN...SLEET...OR SNOW
BEFORE CHANGING TO RAIN. ANY AMOUNTS WILL BE LIGHT...BUT WILL NEED
TO MONITOR FOR A POTENTIAL ADVISORY WHEN THE EVENT DRAWS CLOSER.
SUNDAY NIGHT THE RAIN WILL GRADUALLY END FROM WEST TO EAST ACROSS
THE AREA. TEMPERATURES REMAIN QUITE MILD WITH NO STRONG COLD AIR
ADVECTION BEHIND THIS FEATURE...SO EXPECT MOST OF THE PRECIP TO
REMAIN RAIN BEFORE ENDING. MAY SEE A FEW WET FLAKES MIX IN ACROSS
THE HIGHER TERRAIN EAST OF LAKE ONTARIO AND ALSO ON THE HILLS OF THE
SOUTHERN TIER. WILL ALSO NEED TO MONITOR FOR POTENTIAL FREEZING
DRIZZLE IF DEEP LOW LEVEL MOISTURE FIELDS OF THE NAM VERIFY. ON
MONDAY A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE LOWER
LAKES. THIS WILL BRING A RARE DRY DAY WITH TEMPS ALOFT NOT COLD
ENOUGH TO SUPPORT ANY LAKE RESPONSE. SHOULD SEE AT LEAST A LITTLE
SUN IN THE MORNING BEFORE MID CLOUDS BEGIN TO INCREASE AGAIN AHEAD
OF THE NEXT SYSTEM.
MONDAY NIGHT THE NEXT PACIFIC LOW WILL MOVE EAST ACROSS THE GREAT
LAKES. ONCE AGAIN THIS LOW WILL PASS BY TO OUR NORTH. THIS SHOULD
ALLOW MOST OF THE PRECIP TO FALL AS JUST RAIN ACROSS MOST OF THE
AREA. ONE EXCEPTION MAY BE ACROSS THE NORTH COUNTRY AGAIN WHERE
TEMPS ALOFT ARE A LITTLE COLDER AND THE BOUNDARY LAYER MAY STILL BE
BELOW FREEZING. THIS MAY RESULT IN A WINTRY MIX IN THAT AREA.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AN AREA OF LOW PRESSURE WILL MOVE FROM THE UPPER LAKES INTO QUEBEC
DURING THE DAY TUESDAY...DEEPENING IN THE PROCESS AS THE ASSOCIATED
MID LEVEL TROUGH SHARPENS AND DIGS SOUTHEAST. COLD AIR WILL RUSH
BACK INTO THE AREA LATER TUESDAY THROUGH THE END OF THE PERIOD WITH
850MB TEMPS DROPPING INTO THE MID TEENS BELOW ZERO CELSIUS AGAIN.
THIS WILL BRING TEMPERATURES BACK BELOW NORMAL AGAIN FOR WEDNESDAY
THROUGH FRIDAY WITH MORE LAKE EFFECT SNOW. THIS TIME...THE FLOW
APPEARS TO BE MORE NORTHWEST AT THIS EARLY JUNCTURE...WHICH WOULD
SUGGEST A MORE LIMITED LAKE RESPONSE TO THE SOUTHEAST OF THE LAKES.
RAIN WILL CHANGE TO SNOW DURING THE DAY TUESDAY WITH FALLING TEMPS
IN THE AFTERNOON. AFTER THAT...WILL CARRY CHANCE POPS WEDNESDAY AND
THURSDAY WITH LIKELY TO THE SOUTHEAST OF THE LAKES. BY FRIDAY THE
FORECAST UNCERTAINTY INCREASES QUICKLY WITH A COMPLEX INTERACTION
BETWEEN THE NEXT PACIFIC WAVE AND A DEEP TROUGH OVER ATLANTIC
CANADA. WILL JUST INDICATE A CHANCE OF SNOW FRIDAY TO INDICATE THIS
POTENTIAL.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
THE INTENSE SNOW BAND OFF LAKE ERIE WILL REMAIN SOUTH OF THE KBUF
TERMINAL AND WEAKEN GRADUALLY OVERNIGHT. EXPECT VFR CONDITIONS TO
PREVAIL THROUGH MOST OF THE TAF PERIOD VCNTY KBUF AND KIAG.
FARTHER SOUTH AT KJHW...LIFR TO IFR CONDITIONS IN STEADY SNOW AND
BLSN WILL BE THE RULE UNTIL ABOUT 09Z. AFTER THAT CIGS/VSBYS WILL
LIFT TO MVFR BEFORE IMPROVING TO VFR AROUND 16Z SATURDAY.
EAST OF LAKE ONTARIO...THE INTENSE SNOW BAND WILL STAY SOUTH OF
KART. THEREFORE...EXPECT MAINLY VFR CONDITIONS AT THIS SITE.
BRISK WEST TO SOUTHWEST SURFACE WINDS WILL SUBSIDE SOMEWHAT TONIGHT
AND SATURDAY AS HIGH PRESSURE RIDGES EAST ACROSS THE MIDDLE ATLANTIC
STATES.
OUTLOOK...
SATURDAY NIGHT...VFR
SUNDAY...VFR/MVFR IN SHOWERS AND POSSIBLE MIXED PCPN.
MONDAY...VFR.
TUESDAY...VFR/MVFR WITH CHANCE OF SHOWERS
WEDNESDAY...VFR/MVFR IN SNOW SHOWERS.
&&
.MARINE...
WESTERLY GALES WILL CONTINUE THROUGH MID TO LATE EVENING ON BOTH
LAKES ERIE AND ONTARIO BEFORE SLOWLY DIMINISHING OVERNIGHT. SMALL
CRAFT ADVISORY CONDITIONS WILL CONTINUE THROUGH MOST OF THE WEEKEND
BEFORE WINDS DIMINISH ON MONDAY AS A RIDGE BUILDS OVER THE LOWER
LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST SATURDAY FOR
NYZ006>008.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR NYZ012-
019-020-085.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
NYZ021.
MARINE...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LEZ020.
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR
LOZ042>045-062>065.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...TMA
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...TJP
MARINE...HITCHCOCK/TJP
