FXUS61 KBUF 091254 PAA
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
754 AM EST WED DEC 9 2009
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE NEAR CHICAGO THIS MORNING WILL LIFT
ACROSS MICHIGAN TO LAKE HURON BY THIS EVENING. THE UNUSUALLY STRONG
STORM SYSTEM WILL THEN CROSS SOUTHERN ONTARIO TO QUEBEC BY THURSDAY
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF HIGH WINDS ACROSS
THE REGION WITH WIND DRIVEN LAKE EFFECT SNOWS DEVELOPING TONIGHT AND
CONTINUING INTO AT LEAST FRIDAY. VERY HEAVY LAKE EFFECT SNOWS WILL
BE FOUND IN THE TRADITIONAL SNOWBELT AREAS EAST OF BOTH LAKES ERIE
AND ONTARIO.
&&
.NEAR TERM /THROUGH TONIGHT/...
978MB LOW PRESSURE SITUATED NEAR CHICAGO AT 12Z WILL CONTINUE TO
DEEPEN AS IT LIFTS NORTHEAST TO GEORGIAN BAY TODAY...THEN WILL
SLOWLY BEGIN TO FILL AS IT TRACKS INTO WESTERN QUEBEC TONIGHT. A
WARM FRONT EXTENDING EASTWARD FROM THE LOW WILL WORK ACROSS
WESTERN AND CENTRAL NEW YORK STATE THIS MORNING...THEN WILL BE
FOLLOWED THIS AFTERNOON BY A RATHER SHARP COLD FRONTAL PASSAGE.
THE APPROACH AND PASSAGE OF THIS INTENSE EARLY WINTER STORM WILL
RESULT IN A MYRIAD OF WEATHER CONCERNS FOR OUR AREA DURING THE NEAR
TERM PERIOD. THESE ARE AS FOLLOWS:
1. PRECIPITATION TODAY...AS OF 1250Z WIDESPREAD WARM ADVECTIVE
PRECIP CONTINUES ACROSS ALL OF THE FORECAST AREA. THIS WILL
CONTINUE INTO MID MORNING BEFORE TAPERING OFF FROM SOUTHWEST TO
NORTHEAST IN CONJUNCTION WITH THE DEPARTURE OF THE MAIN SWATH OF
LOWER AND UPPER LEVEL JET SUPPORT...AND AS DRY SLOTTING WORKS INTO
THE AREA FROM THE OHIO VALLEY. METAR AND MESONET OBS INDICATE THAT
THE MAJORITY OF THE PRECIP IS NOW IN THE FORM OF RAIN FROM THE
GENESEE VALLEY WESTWARD...WITH A MIX OF SNOW/SLEET/FREEZING RAIN
FURTHER EAST. EXPECT THIS GENERAL SPREAD IN PRECIP TYPES TO PRETTY
CONTINUE FOR ANOTHER HOUR OR SO...BEFORE CONTINUING WARM ADVECTION
BOTH AT THE SURFACE AND ALOFT HELPS TO FORCE A TRANSITION TO ALL
RAIN BY MIDDAY PRETTY MUCH EVERYWHERE. HAVE DROPPED THE WINTER
WEATHER ADVISORIES FROM MONROE AND LIVINGSTON COUNTIES
WESTWARD...WHILE LEAVING ADVISORIES IN EFFECT UNTIL 10 AM/NOON FOR
OUR REMAINING ZONES.
WITH THE ARRIVAL OF THE WARM SECTOR/DRY SLOT...WE STILL
EXPECT THE PRECIPITATION TO TAPER OFF TO JUST SOME SCATTERED SHOWERS
FOR A WHILE LATER THIS MORNING AND EARLY THIS AFTERNOON...BEFORE THE
AFOREMENTIONED COLD FRONT APPROACHES ALONG WITH AN INCREASING SHOWER
THREAT DURING THE MID TO LATE AFTERNOON.
2. WINDS...THE PASSAGE OF SUCH AN INTENSE LOW TO OUR NORTH AND WEST
IS CLIMATOLOGICALLY FAVORABLE FOR STRONG WINDS ACROSS WESTERN AND
NORTH CENTRAL NEW YORK...AND THIS EVENT WILL BE NO EXCEPTION WITH
TWO PERIODS OF STRONGER WINDS ANTICIPATED. THE FIRST OF THESE WILL
OCCUR FROM NOW THROUGH EARLY AFTERNOON AND WILL BE ASSOCIATED WITH
THE PASSAGE OF THE MAIN LOW LEVEL JET...WITH A STRONG SOUTH TO
SOUTHEASTERLY LOW-LEVEL FLOW PRODUCING SOME ADVISORY-LEVEL GUSTS
ACROSS THE HIGHER TERRAIN SOUTH OF BUFFALO AND IN THE BLACK RIVER
VALLEY EAST OF LAKE ONTARIO. THE SECOND OF THESE...THE MAIN WIND
EVENT...WILL BEGIN WITH THE PASSAGE OF THE SURFACE COLD FRONT LATER
THIS AFTERNOON AND EARLY THIS EVENING...WITH WINDS TURNING
SOUTHWESTERLY AND INCREASING SHARPLY IN THE COLD ADVECTION REGIME
BEHIND THE FRONT...WITH THE ASSOCIATED DOWNWARD MOMENTUM TRANSPORT
HELPING TO BRING SOME WARNING CRITERIA /50-55 KNOT/ GUSTS DOWN TO
THE SURFACE. HIGH WIND WARNINGS ARE CURRENTLY IN EFFECT TO COVER
BOTH OF THESE BOUTS OF STRONGER WINDS...AND THESE WILL BE LEFT AS IS
WITH THE EARLY MORNING FORECAST ISSUANCE.
3. LAKESHORE FLOODING...THE PROLONGED PERIOD OF STRONG SOUTHWESTERLY
WINDS EXPECTED LATE THIS AFTERNOON AND TONIGHT WILL LEAD TO A SEICHE
EVENT ON LAKE ERIE...WITH LAKE LEVELS VERY LIKELY TO REACH FLOOD
STAGE ALONG THE LAKE ERIE SHORELINE OF ERIE AND CHAUTAUQUA COUNTIES.
FOR THIS REASON...THE EXISTING LAKE SHORE FLOOD WATCH FOR THESE TWO
COUNTIES HAS BEEN UPGRADED TO A WARNING.
4. DEVELOPING LAKE EFFECT TONIGHT...AS IF ALL OF THE ABOVE WASN'T
ENOUGH...MUCH COLDER AIR WILL CHARGE INTO THE REGION TONIGHT BEHIND
THE COLD FROPA...WITH 850 MB READINGS FALLING TO -6C IN THE WEST AS
EARLY AS THIS EVENING...AND TO THE -10C TO -12C RANGE EVERYWHERE BY
THURSDAY MORNING. WITH LAKE TEMPS STILL IN THE +7 TO +8C
RANGE...THIS WILL EASILY SET OFF A STRONG LAKE RESPONSE...WITH LAKE
EFFECT SNOWS SETTING UP OFF OF BOTH LAKES ON A SOUTHWEST TO
WEST-SOUTHWEST FLOW. OFF LAKE ERIE...THE LAKE SNOWS WILL BEGIN TO
SET UP AS EARLY AS THIS EVENING IN THE BUFFALO AREA ON A SOMEWHAT
SHEARED SOUTHWESTERLY FLOW...THEN SLOWLY MIGRATE SOUTHWARD TO THE
IMMEDIATE BUFFALO SOUTHTOWNS AND BECOME BETTER ORGANIZED LATER
TONIGHT AS THE FLOW VEERS A BIT MORE TO WSW AND BECOMES BETTER
ALIGNED. OFF LAKE ONTARIO...THIS SAME SCENARIO WILL UNFOLD ABOUT 3-4
HOURS LATER...WITH LAKE SNOWS OVERSPREADING THE WATERTOWN AREA AND
NORTHERN JEFFERSON/LEWIS COUNTIES BY LATE TONIGHT.
WHILE SNOWFALL ACCUMULATIONS WILL BE HELD IN CHECK BY THE
AFOREMENTIONED SHEAR AND STRONG WINDS...WHICH WILL HELP TO LIMIT THE
ORGANIZATION OF THE LAKE SNOWS...THE COMBINATION OF THE STRONG WINDS
AND FALLING SNOW WILL STILL RESULT IN VERY DIFFICULT TRAVEL
CONDITIONS DEVELOPING DURING THE COURSE OF TONIGHT...WITH VERY POOR
VISIBILITIES EXPECTED IN EXTENSIVE BLOWING AND DRIFTING SNOW. FOR
THIS REASON AND THE FACT THAT WINTER WEATHER ADVISORIES REMAIN IN
EFFECT FOR THIS MORNING...WINTER STORM WATCHES HAVE BEEN LEFT IN
PLACE ACROSS THE EXPECTED LAKE EFFECT AREAS FOR TONIGHT.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THE ANOMALOUSLY DEEP STORM SYSTEM THAT WILL BOTTOM OUT AT HURRICANE
STRENGTH (<980 MB) WILL START TO FILL DURING THE DAY THURSDAY AS IT
WILL LIFT ACROSS SOUTHERN QUEBEC. IN THE WAKE OF THE STRONG STORM...
A VERY TIGHT SFC PRESSURE GRADIENT WILL KEEP STRONG WINDS ACROSS ALL
OF WESTERN NEW YORK. WHILE A HIGH WIND WARNING WILL REMAIN IN EFFECT
ON THURSDAY...WINDS WILL PROBABLY BE OF ADVISORY STRENGTH FOR THE
VAST MAJORITY OF THE TIME. WORKING AGAINST A CLASSIC WIND EVENT WILL
BE TWO FACTORS...(1) THE SFC LOW WILL BE FILLING AS IT EXITS ACROSS
QUEBEC AND (2) THERE WILL BE A LACK OF STRONG WINDS (<50 KTS) TO MIX
DOWN TO THE SFC FROM ALOFT.
OF MORE CONCERN ON THURSDAY WILL BE THE WIND WHIPPED LAKE SNOWS
THAT WILL BE FOCUSED ON THE LAKE ERIE SNOWBELT SOUTH OF BUFFALO AND
ALSO ACROSS THE TUG HILL. LETS START WITH LAKE ERIE.
THE LOWER BOUNDARY LAYER (BLO 700MB/10K FT) FLOW ON THURSDAY WILL
AVERAGE 260 DEG OFF LK ERIE...SO THIS WILL MEAN THAT THE BULK OF THE
LK SNOW WILL BE AIMED AT THE SOUTH TOWNS (ORCHARD PK/HAMBURG). THE
LAKE SNOW BAND WILL LIKELY START THE DAY IN...OR JUST SOUTH...OF THE
BUF METRO AREA THEN WILL SETTLE A LITTLE TO THE SOUTH. WORKING
AGAINST HIGH SNOWFALL RATES (>1" PER HOUR) WILL BE THE STRONG
WINDS...BUT ON THE OTHER HAND...30-50 MPH WINDS WILL PRODUCE NEAR
BLIZZARD CONDITIONS WITHIN THE LAKE SNOW. SNOWFALL RATES THAT WOULD
OTHERWISE BE IN THE 1-3"/HR RANGE WILL PROBABLY HOLD CLOSE TO THE
LOW END OF THE RANGE WITH A MORE DIFFUSE CONCENTRATION OF THE PLUME
ITSELF. REGARDLESS...SNOW ACCUMS THURSDAY SHOULD REACH 6 TO 10
INCHES. THE MAIN IMPACT THOUGH WILL BE FROM THE 20:1 SNOW BEING
BLOWN BY THE 30 TO 50 MPH WINDS...PRODUCING WHITE OUT CONDITIONS.
THIS WILL LEAD TO VERY DIFFICULT/CHALLENGING TRAVEL CONDITIONS...
BOTH BY LAND AND AIR...FOR MUCH OF THE BUF METRO AREA THURSDAY
MORNING.
OFF LK ONTARIO...A 250 FLOW SHOULD SET UP A RATHER WIDE AND DIFFUSE
LAKE SNOW BAND NEAR OR JUST NORTH OF WATERTOWN. THE MOISTURE PROFILE
WILL BE DEEPER THAN THAT OF LK ERIE...INCLUDING A 4-5K FT THICK
DENDRITIC GROWTH ZONE. AGAIN...THE STRONG WINDS SHOULD KEEP THE LAKE
BAND FROM BECOMING CONCENTRATED BUT WILL ALSO PRODUCE WHITE OUT
BLIZZARD CONDITIONS. THE BAND SHOULD GENERALLY REMAIN NORTH OF THE
TUG HILL THROUGH THE DAY...WITH SNOWFALL AMOUNTS OF 5 TO 8 INCHES.
MORE TYPICAL LAKE PLUMES WILL SET UP THURSDAY NIGHT AS THE GRADIENT
WILL DECREASE A BIT AND WINDS WILL VEER TO ABOUT 270 WITH H85
DROPPING TO -20C AND A RISING EQUILIBRIUM LEVEL OVER BOTH LAKES.
THE LAKE SNOWS OFF LK ERIE WILL SETTLE ACROSS SKI COUNTRY DURING THE
COURSE OF THURSDAY NIGHT WITH SNOWFALL RATES OF 1-2"/HR PRODUCING
NIGHTTIME ACCUMS OF A FOOT OR MORE OF LIGHT FLUFFY 30:1 SNOW. THE
LAKE SNOWS SHOULD BE EVEN MORE IMPRESSIVE OFF LK ONTARIO AS A
MULTI-LAKE ENHANCED BAND OF SNOW WILL ABSOLUTELY BURY THE TUG HILL
PLATEAU WITH ACCUMS EASILY EXCEEDING A FOOT. ALL OF THIS LOW DENSITY
SNOW WILL CONTINUE TO BE BLOWN AND ALSO DRIFTED AT THIS POINT...WITH
TRAVEL NEARLY IMPOSSIBLE. THIS WILL INCLUDE INTERSTATE 81 SOUTH OF
WATERTOWN AND POSSIBLY THE NEW YORK STATE THRUWAY BETWEEN ERIE AND
HAMBURG.
ITS WORTH NOTING THAT LOW TEMPS IN THE TEENS AND LOW 20S THURSDAY
NIGHT WILL COMBINE WITH GUSTY WINDS TO PRODUCE OUR LOWEST WIND CHILL
VALUES OF THE YOUNG SEASON...WITH VALUES WITHIN A FEW DEGREES OF
ZERO.
FOR FRIDAY...THE BITTER COLD -16 TO -20C WILL REMAIN OVER THE REGION
WITH A 270 FLOW PERSISTING OFF BOTH LAKES. MEMORABLE LAKE SNOWS WILL
CONTINUE EAST OF BOTH LAKES. 'SKI COUNTRY' OF SRN ERIE COUNTY AND
THE WRN SOUTHERN TIER SHOULD PICK UP AT LEAST 6 MORE INCHES OF
ACCUMULATION WHILE THE TUG HILL PLATEAU COULD BE IN LINE FOR ANOTHER
FOOT. THE REST OF THE REGION CAN EXPECT SCATTERED LAKE SNOW SHOWERS
WITH SFC TEMPS ONLY REACHING THE MID 20S AND WIND CHILLS IN THE
SINGLE DIGITS.
SFC BASED HIGH PRESSURE OVER THE OHIO VALLEY FRIDAY EVENING WILL
BUILD NORTHWARDS DURING THE COURSE OF FRIDAY NIGHT AS THE REMNANTS
OF THE ARCTIC H5 TROUGH WILL FINALLY LIFT OUT ACROSS EASTERN CANADA.
THE STEERING WINDS WILL VEER A LITTLE MORE TO THE NORTHWEST...AND
THIS WILL SEND THE WEAKENING SNOW BANDS FURTHER SOUTH.
ON SATURDAY...LOW LEVEL RIDGING WILL BE IN PLACE OVER OUR REGION
WHILE A ZONAL FLOW WILL BE FOUND ALOFT. WEAK WARM ADVECTION WITHIN
THIS PATTERN WILL ELEVATE H85 TEMPS TO BETWEEN -10/-12C...BUT THIS
WILL STILL BE COLD ENOUGH FOR RESIDUAL LAKE SNOW SHOWERS. A LOWERING
CAP AND HIGH SHEAR WILL PROBABLY END THE LAKE SNOWS OFF LK ERIE...
BUT A BAND OF LK SNOW (PRIMED FROM LK SUPERIOR) WILL STILL EXTEND
ACROSS OSWEGO COUNTY WITH ADDITIONAL MINOR ACCUMS.
EXPECT ANOTHER COLD NIGHT SATURDAY NIGHT AS WINDS WILL BE LIGHT. A
FRESH SNOWPACK...ESPECIALLY DOWNWIND OF THE LAKES...WILL GUARANTEE
BELOW NORMAL TEMPERATURES FOR ANOTHER NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE COLD PATTERN LOOKS TO EASE FOR A COUPLE OF DAYS DURING THIS
PERIOD WITH REGION SANDWICHED BETWEEN THE TWO JET STREAMS ON SUNDAY
AND MONDAY. WEAK RIDGING SHOULD SLIDE JUST TO OUR EAST OF
SUNDAY...ALLOWING FOR DRY AND TRANQUIL DAY UNDER A LIGHT SOUTHERLY
FLOW. 850 MB TEMPS OF -2C TO -4C SHOULD TRANSLATE INTO M-U 30S TO
NEAR 40 WITH A BIT OF SUNSHINE. WITH BOTH EC AND GFS KEEPING
MOISTURE WELL TO OUR SOUTH...LOWERED POPS BELOW SLGT CHC.
MODELS DIVERGE ON MON-TUES...WITH ECMWF SWINGING COLD FRONT ACROSS
THE AREA MONDAY WHILE GFS HOLDS IT OFF TILL LATER TUES. WILL SPLIT
THE DIFFERENCE AND TAKE IT ACROSS THE EASTERN LAKES MON NT OR TUES
AM. THIS WOULD ALLOW FOR ANOTHER DECENT DAY ON MONDAY...MAINLY DRY
AND MILD...WILL BRING CHC POPS BACK IN ON MON NT AND DROP TO SLGT
CHC TUES ON COLDER NNW FLOW...CHC SE OF LAKES.
BOTH MODELS DO AGREE THAT THERE WILL BE A VERY COLD AIRMASS BEHIND
THIS FRONT OVER THE UPPER LAKES BY MIDWEEK WITH 850 MB TEMPS OF -25C
OR LOWER. SOME OF THIS MAY BE DRAWN DOWN INTO OUR REGION BY LATER
NEXT WEEK...SO LOOK FOR BELOW NORMAL TEMPS.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
INTENSE LOW PRESSURE NEAR CHICAGO WILL MOVE ACROSS MICHIGAN TO
GEORGIAN BAY BY LATE THIS AFTERNOON...THEN ON INTO WESTERN QUEBEC
TONIGHT. A BROAD SWATH OF PRECIPITATION AHEAD OF THIS LOW WILL
CONTINUE TO LIFT NORTHEAST ACROSS OUR REGION THIS MORNING...WITH
SNOW MIXING WITH AND CHANGING TO RAIN FROM SOUTHWEST TO NORTHEAST
AS WARMER AIR WORKS IN BOTH ALOFT AND AT THE SURFACE.
THE RAIN WILL EVENTUALLY TAPER OFF BY LATE MORNING/EARLY AFTERNOON
WITH CONDITIONS IMPROVING TO VFR OVER MOST SPOTS FOR A FEW
HOURS...BEFORE A POWERFUL COLD FRONT TRAILING THE LOW PASSES
ACROSS THE AREA IN THE 21Z-00Z TIME FRAME. THIS FRONT MAY BE
ACCOMPANIED BY A ROUND OF MVFR SHOWERS.
BEHIND THE FRONTAL PASSAGE...A STRONG SOUTHWESTERLY FLOW OF MUCH
COLDER AIR WILL OVERSPREAD THE REGION THIS EVENING...WITH
SUSTAINED SURFACE WINDS INCREASING INTO THE 25-35 KNOT
RANGE...WITH GUSTS REACHING AS HIGH AS 45-50 KNOTS.
AS THE COLDER AIR OVERSPREADS THE RELATIVELY WARMER GREAT
LAKES...SNOW SQUALLS WILL ALSO DEVELOP NORTHEAST OF THE
LAKES...AFFECTING THE KBUF/KIAG/KROC TERMINALS BEGINNING THIS
EVENING...AND KART BEGINNING OVERNIGHT. THE COMBINATION OF THE
SNOW SQUALLS AND STRONG WINDS WILL RESULT IN CONDITIONS
DETERIORATING TO IFR AND THEN LIFR IN THE AREAS OF LAKE EFFECT
TONIGHT...WITH SOME IFR TO MVFR SNOW SHOWERS FOUND ELSEWHERE.
OUTLOOK...
THURSDAY...MAINLY MVFR/IFR SNOW SHOWERS AND SQUALLS...MAINLY
SOUTH OF KBUF AND KROC. STRONG SURFACE WINDS CONTINUING.
FRIDAY...VFR/MVFR IN SNOW SHOWERS.
SATURDAY...VFR/MVFR IN SNOW SHOWERS.
SUNDAY...MAINLY VFR.
&&
.MARINE...
A VERY DEEP STORM SYSTEM OF HURRICANE STRENGTH WILL MOVE FROM NEAR
CHICAGO THIS MORNING TO LAKE HURON THIS EVENING...THEN WILL CROSS
SOUTHERN ONTARIO TO WESTERN QUEBEC BY DAYBREAK THURSDAY. WINDS WILL
INCREASE TO GALE FORCE ON LAKE ERIE BY LATE TODAY...BEFORE BUILDING
TO STORM FORCE TONIGHT. HIGH GALE TO MINIMUM STORM FORCE WINDS WILL
THEN PERSIST ACROSS LAKE ERIE ON THURSDAY.
FOR LAKE ONTARIO...WINDS WILL INCREASE TO GALE FORCE TONIGHT WITH
OCCASIONAL STORM FORCE WIND GUSTS LATE TONIGHT INTO THURSDAY
MORNING.
AS THE DEEP LOW LIFTS AWAY ACROSS QUEBEC THURSDAY NIGHT AND
FRIDAY...WINDS WILL VERY SLOWLY SUBSIDE ACROSS BOTH LAKES.
WAVES ON BOTH LAKES WILL LIKELY BUILD TO BETWEEN 15 AND 20 FEET.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HIGH WIND WARNING UNTIL 7 PM EST THURSDAY FOR NYZ012-019>021-
085.
LAKESHORE FLOOD WARNING FROM 3 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR NYZ010-019-085.
WINTER STORM WATCH FROM 7 PM EST THIS EVENING THROUGH FRIDAY
EVENING FOR NYZ012-019>021-085.
HIGH WIND WARNING UNTIL 7 PM EST THURSDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ006>008.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH FRIDAY EVENING
FOR NYZ006>008.
HIGH WIND WARNING FROM 5 PM THIS AFTERNOON TO 7 PM EST
THURSDAY FOR NYZ003>006-013-014.
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NYZ004-005-014.
HIGH WIND WARNING FROM 2 PM THIS AFTERNOON TO 7 PM EST
THURSDAY FOR NYZ001-002-010-011.
WINTER STORM WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY
EVENING FOR NYZ010-011.
MARINE...STORM WARNING FROM 2 PM THIS AFTERNOON TO 7 PM EST THURSDAY
FOR LEZ020-040-041.
GALE WARNING FROM 7 PM THIS EVENING TO 7 PM EST
THURSDAY FOR LOZ042>045-062>065.
GALE WARNING FROM 1 AM TO 7 PM EST THURSDAY FOR
SLZ022-024.
&&
$$
SYNOPSIS...RSH
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...SFM
AVIATION...JJR/SFM
MARINE...RSH
