Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 192352
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
652 PM EST WED NOV 19 2014

.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL BRING A LIGHT GENERAL SNOWFALL
ACROSS MUCH OF THE REGION EARLY TONIGHT BEFORE LAKE EFFECT SNOW
AGAIN FORMS ON A FRESHENING ARCTIC AIRMASS. SOUTHWEST WINDS WILL
AGAIN PUSH THESE HEAVY LAKE EFFECT SNOWS OVER THE SAME AREAS THAT
RECEIVED EARLIER LAKE SNOWS. EXPECT SOME SOUTHWARD MOVEMENT TO THE
SNOWBANDS TOMORROW NIGHT BEFORE THE SNOW BANDS LIFT NORTHWARD WHILE
DIMINISHING IN INTENSITY DURING THE DAY FRIDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
....SECOND SIGNIFICANT LAKE EFFECT SNOW EVENT TO IMPACT AREAS HARD
HIT DOWNWIND OF LAKE ERIE AND LAKE ONTARIO...

FOR THIS EVENING...A GENERAL LIGHT SNOWFALL WILL CROSS THE REGION
WITH LIGHT ISENTROPIC ASCENT AHEAD OF A SHARPENING UPPER LEVEL
TROUGH. SNOWFALL AMOUNTS WITH THIS SYSTEM WILL BE LIGHT WITH A
GENERAL HALF TO TWO INCHES ACROSS THE REGION.

ATTENTION WILL THEN TURN TO THE SECOND LAKE EFFECT SNOW EVENT OF THE
WEEK.

THE BROAD SCALE PATTERN WILL AGAIN FEATURE A DEEP TROUGH OVER THE
GREAT LAKES REGION WITH A CLOSED 500 HPA LOW NEAR THE SOO. 850 HPA
TROUGH IS ALSO DEEP WITH A CLOSED LOW NEAR LAKE HURON TONIGHT. THIS
PATTERN WITH THE DEEPNESS AND LOCATION OF THE CLOSED LOWS IS VERY
SIMILAR TO PRIOR EVENTS THAT HAVE PRODUCED SIGNIFICANT LAKE EFFECT
SNOW DOWNWIND OF BOTH EASTERN GREAT LAKES.

A LOOK AT THE LAKE EFFECT PARAMETERS...THEY AGAIN WILL LINE UP WITH
SIGNIFICANT LAKE EFFECT SNOW EVENTS. BEHIND THE BRIEF WARMING ALOFT
THIS EVENING A COLD FRONT WILL CROSS THE REGION WITH A FRESHENING
BLAST OF ARCTIC AIR DROPPING TEMPERATURES DOWN TO -14C.

OFF LAKE ERIE...BY MIDNIGHT WINDS WILL AGAIN ALIGN ON A SW FLOW WITH
LAKE INDUCED EQUILIBRIUM LEVELS RISING TO 15K FEET. MOISTURE WILL
DEEPEN WITHIN THE SNOW DENDRITIC GROWTH ZONE LATER OVERNIGHT WITH A
BAND OF SNOW EXPECTED OVER NIAGARA COUNTY. AS THE BASE OF THE
ANOMALOUSLY DEEP TROUGH SLIDES FROM THE CENTRAL GREAT LAKES EASTWARD
THE STEERING WINDS IN THE LOWER LEVELS WILL BECOME MORE WESTERLY.
THIS WILL DROP THE LAKE EFFECT SNOW BAND SOUTHWARD...CROSSING THE
NORTHTOWNS OF BUFFALO LATE OVERNIGHT. INITIALLY WE ARE EXPECTING
SNOWFALL RATES OF AN INCH PER HOUR. THEN AS THE CAPPING INVERSION
GROWS...AND THE FLOW PASSES THE ENTIRE LONG FETCH OF THE LAKE EXPECT
SNOWFALL RATES TO INCREASE SUCH THAT 3 TO 4 INCHES PER HOUR WILL BE
LIKELY BY THURSDAY MORNING. AT THIS TIME THE BAND OF SNOW WILL
LIKELY BE JUST TO THE SOUTH OF A LINE FROM BUFFALO TO BATAVIA...VERY
SIMILAR TO THIS PRIOR EVENT THAT JUST ENDED. WHILE A HALF FOOT OR
MORE OF SNOW IS EXPECTED BY SUNRISE TOMORROW...UP TO 2 FEET WILL BE
EXPECTED AGAIN THROUGH THE DAYLIGHT HOURS TOMORROW. WITH THE BAND OF
SNOW NEARLY STATIONARY...EXPECT AGAIN A NARROW BAND OF SIGNIFICANT
SNOW. IT IS STILL A LITTLE TO EARLY TO TELL WHETHER THIS BAND OF
HEAVY SNOW WILL ALIGN WITH THE AXIS OF HEAVY SNOW FROM THE PRIOR
EVENT (WHICH IF IT DOES IT WOULD YIELD WEEKLY SNOW TOTALS NEAR 100
INCHES) OR FALL JUST SEVERAL MILES NORTH OR SOUTH OF THIS LINE OF
HEAVY SNOW FROM THE FIRST EVENT. BY LATE AFTERNOON AS THE AXIS OF
THE UPPER LEVEL TROUGH SWINGS ACROSS LAKE ERIE THE LAKE EFFECT
SNOWBAND WILL REFOCUS UPON THE SKI COUNTRY AND POINTS FARTHER AS THE
EVENING HOURS DRAW UPON US.

OFF LAKE ONTARIO...THE LAKE EFFECT SNOWBAND WILL INITIALLY FORM
ALONG THE SAINT LAWRENCE VALLEY IN THE HOURS AFTER MIDNIGHT. THESE
SW WINDS WILL VEER SLIGHTLY THROUGH THE LATER PORTIONS OF THE NIGHT
WITH THE LAKE EFFECT SNOWBAND DROPPING DOWN INTO THE METRO WATERTOWN
AREA AND OUT TOWARDS FORT DRUM. THIS SOUTHWEST WIND FLOW WILL LIMIT
THE SNOWFALL RATE INITIALLY WITH SNOWFALL RATES OF AROUND AN INCH PER
HOUR THROUGH THE VALLEY. AS THE WINDS VEER SOME...LAKE INDUCED
EQUILIBRIUM LEVELS RISE TOWARDS 16 TO 18K FEET AND WIND SHEER
MINIMIZES EXPECT THESE SNOWFALL RATES TO INCREASE TO AROUND 3 INCHES
PER HOUR BY AROUND DAWN TOMORROW. A GOOD CONVERGENT FLOW ALONG THE
LAKE AXIS WILL BRING A BAND OF LAKE EFFECT SNOW EASTWARD ACROSS
JEFFERSON AND LEWIS COUNTY. SNOWFALL RATES OFF LAKE
ONTARIO...SIMILAR TO THE PRIOR EVENT MAY NOT BE AS GREAT AS OFF
LAKE ERIE DUE TO THE `SOUTHWEST` FLOW. THIS WILL YIELD SNOWFALL
TOTALS TOMORROW A LITTLE LESS THAN LAKE ERIE WITH 1.5 TO 2 FEET OF
SNOW EXPECTED THROUGH THE DAYLIGHT HOURS. WHILE THE BAND OF SNOW
WILL BE FOCUSED TOWARDS WATERTOWN/FORT DRUM AND THEN THE NORTHERN
TUG...AN UPSLOPE FLOW THROUGH THE ENTIRE TUG HILL WILL SUPPORT LIGHT
SNOW SHOWERS SOUTH OF THE BAND OF HEAVIEST SNOWFALL.

OFF OF BOTH LAKES...A RELATIVELY HIGH CAPPING INVERSION AND A FAIRLY
DEEP MIXED PHASE CLOUD (-10C ISOTHERM ARND 5K FT) WILL ONCE AGAIN
PRESENT THE POTENTIAL FOR SOME THUNDERSNOW WITHIN THE HEART OF THE
SNOWBANDS. HAVE THUS ADDED THIS POTENTIAL TO THE FORECAST PACKAGE
FOR THE OVERNIGHT...BUT WILL AWAIT ADDITIONAL GUIDANCE BEFORE DOING
THE SAME FOR THE DAYLIGHT HOURS OF THURSDAY.

OUTSIDE THESE TWO SNOWBANDS THERE WILL BE SUNNY BREAKS THROUGH THE
DAY TOMORROW. ANOTHER BITTERLY COLD NIGHT AND DAY ARE ON TAP UNDER
THIS COLD ARCTIC AIRMASS. LOWS TONIGHT WILL RANGE THROUGH THE TEENS
ACROSS THE SOUTHERN TIER AND NORTH COUNTRY TO LOWER 20S ELSEWHERE.
HIGHS TOMORROW WILL ONLY ADD ABOUT 10 DEGREES TO THE PRIOR NIGHTS
LOWS. WITH THE GUSTY WINDS SINGLE DIGITS TO LOW TEENS WIND CHILLS
ARE EXPECTED THROUGH THIS TIME PERIOD.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
LAKE EFFECT STORM ROUND 2 WILL STILL BE ONGOING THROUGH THE SHORT
TERM PERIOD AND WILL BE THE MAIN FOCUS OF THE FORECAST. FROM A
SYNOPTIC STANDPOINT A STRONG MID LEVEL SHORTWAVE WILL CROSS THE
LOWER LAKES THURSDAY EVENING. THIS MAY PRODUCE A FEW SCATTERED SNOW
SHOWERS WITH SPOTTY LIGHT ACCUMULATIONS OUTSIDE OF LAKE EFFECT
AREAS. ANY SYNOPTIC SNOW SHOULD BE OVER WITH BY FRIDAY MORNING. THIS
SHORTWAVE WILL HAVE A SIGNIFICANT IMPACT ON LAKE EFFECT SNOW
LOCATION...VEERING WINDS FROM THE WSW TO THE NORTHWEST THURSDAY
NIGHT AND MOVING THE LAKE EFFECT SNOW AWAY FROM THE HARDEST HIT
AREAS.

OFF LAKE ERIE...
LAKE INDUCED EQUILIBRIUM LEVELS REMAIN AROUND 15K FEET THURSDAY
NIGHT THROUGH FRIDAY MORNING BEFORE DROPPING STEADILY DURING THE DAY
FRIDAY AS HIGH PRESSURE BUILDS INTO THE OHIO VALLEY AND DRIES THE
COLUMN AND LOWERS A SUBSIDENCE INVERSION.

EXPECT A BAND OF HEAVY SNOW WITH SNOWFALL RATES OF AT LEAST 2-3
INCHES PER HOUR TO STILL BE ONGOING ALONG THE LAKE ERIE SHORE FROM
RIPLEY TO THE BUFFALO SOUTHTOWNS AND WYOMING COUNTY EARLY THURSDAY
EVENING. THIS BAND SHOULD PUSH STEADILY SOUTHEAST DURING THE EVENING
AS BOUNDARY LAYER FLOW VEERS...THEN WEAKEN OVERNIGHT AND EVOLVE INTO
MORE OF A NORTHWEST FLOW/UPSLOPE EVENT ALONG THE CHAUTAUQUA RIDGE BY
FRIDAY MORNING. EXPECT MOST OF THE SNOW TO BE CONFINED TO CHAUTAUQUA
AND WESTERN CATTARAUGUS COUNTIES DURING THE DAY FRIDAY WITH THE BEST
SNOW ACROSS THE HIGHER TERRAIN INLAND FROM THE LAKE...AND MUCH
LIGHTER SNOW ALONG THE THRUWAY CORRIDOR. THE LAKE SNOW SHOULD
STEADILY WEAKEN FRIDAY AFTERNOON AS INVERSION HEIGHTS LOWER. FRIDAY
EVENING A WEAK BAND OF SNOW SHOWERS MAY TRY TO MOVE BACK NORTH
TOWARDS BUFFALO AS BOUNDARY LAYER FLOW BACKS TO THE SOUTHWEST...BUT
BY THIS TIME INVERSION HEIGHTS WILL BE CRASHING...SO EXPECT A VERY
QUICK WEAKENING TREND.

OFF LAKE ONTARIO...
LAKE INDUCED EQUILIBRIUM LEVELS WILL PEAK AROUND 18K FEET THURSDAY
NIGHT BEFORE DROPPING STEADILY DURING THE DAY THEN DROPPING OFF EVEN
MORE QUICKLY FRIDAY NIGHT.

EXPECT A BAND OF HEAVY SNOW WITH SNOWFALL RATES OF 3-5 INCHES PER
HOUR TO BE JUST SOUTH OF WATERTOWN AND FORT DRUM EARLY THURSDAY
EVENING. THE BAND WILL SETTLE A LITTLE FARTHER SOUTH TO THE CENTRAL
TUG HILL OVERNIGHT BEFORE REACHING CENTRAL OSWEGO COUNTY BY FRIDAY
MORNING. MESOSCALE MODEL GUIDANCE INCLUDING THE OPERATIONAL NAM
SUGGESTS THE BAND MAY STALL FOR AT LEAST A FEW HOURS ACROSS THE
CENTRAL TUG HILL OVERNIGHT WHEN IT WILL STILL HAVE VERY STRONG
SNOWFALL RATES.

FRIDAY MORNING THE BAND IS FORECAST TO DROP QUICKLY SOUTH ACROSS
OSWEGO COUNTY AS A RAPID WIND SHIFT CROSSES THE LAKE IN THE WAKE OF
THE MID LEVEL SHORTWAVE. THE NAM WOULD SUGGEST THIS WIND SHIFT WILL
OCCUR FAST ENOUGH TO PUSH THE ENTIRE SINGLE BAND BODILY ONSHORE AND
BREAK IT APART INTO MULTIPLE BANDS QUICKLY...WHICH WILL THEN IMPACT
AREAS FROM WAYNE TO OSWEGO COUNTY DURING THE DAY ON FRIDAY. WE HAD A
DISCUSSION WITH WFO BGM ON POTENTIALLY ISSUING A LAKE EFFECT SNOW
WATCH FOR WAYNE AND NORTHERN CAYUGA COUNTIES...HOWEVER WITH SOME
MESOSCALE MODEL GUIDANCE SHOWING A VERY TRANSITORY BAND THERE IS NOT
ENOUGH CONFIDENCE YET ON HIGHER AMOUNTS IN THOSE AREAS BUT THIS WILL
CONTINUE TO BE MONITORED.

LAKE SNOW WILL PROBABLY ALSO SPREAD FARTHER WEST ALONG THE SOUTH
SHORE OF THE LAKE ON FRIDAY BRINGING SPOTTY ACCUMULATIONS TO THE
LAKESHORE OF MONROE COUNTY AND THE EASTERN SUBURBS OF ROCHESTER.

FRIDAY NIGHT BOUNDARY LAYER FLOW WILL BEGIN TO BACK...WHICH WILL
CARRY ONE OR MULTIPLE BANDS OF SNOW BACK NORTH ACROSS OSWEGO COUNTY
DURING THE EVENING...REACHING WATERTOWN WELL AFTER MIDNIGHT.
INVERSION HEIGHTS ARE CRASHING AT THIS POINT UNDER STRONG WARM
ADVECTION...SO THIS SHOULD BE RELATIVELY LIGHT ON THE WAY BACK NORTH.

TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH THE END OF THE
WEEK WITH HIGHS AND LOWS MORE TYPICAL OF JANUARY THAN LATE NOVEMBER.
WINDS WILL STILL BE VERY GUSTY THURSDAY NIGHT WITH SIGNIFICANT
BLOWING AND DRIFTING SNOW IN AND NEAR THE LAKE SNOW BANDS.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
ON SATURDAY HIGH PRESSURE WILL BUILD TO THE MID ATLANTIC COAST AND
ALLOW SOUTHWESTERLY RETURN FLOW TO BEGIN. THE HIGH SHOULD STILL
REMAIN CLOSE ENOUGH TO PROVIDE A DRY DAY WITH TEMPERATURES BEGINNING
TO WARM.

SUNDAY AND MONDAY A COMPLEX AREA OF LOW PRESSURE WILL LIFT THROUGH
THE WESTERN GREAT LAKES AS A MID LEVEL TROUGH DIGS INTO THE NORTHERN
PLAINS. THIS WILL FORCE STRONG HEIGHT RISES AND WARM ADVECTION
DOWNSTREAM ACROSS THE LOWER LAKES AND ALLOW TEMPERATURES TO SOAR...
WITH THE WARMEST DAY COMING MONDAY. TEMPERATURES WILL RISE INTO THE
MID 50S TO LOWER 60S...WITH DEWPOINTS IN THE MID 40S AND PLENTY OF
WIND. OVERNIGHT LOWS WILL ALSO BE MILD. THIS WILL SET THE STAGE FOR
A MAJOR MELTDOWN IN AREAS POUNDED BY LAKE EFFECT SNOW. LATEST MODEL
GUIDANCE DOES NOT SHOW AN EXCESSIVE AMOUNT OF RAIN...WITH THE BEST
RAIN CHANCES COMING ON SUNDAY NIGHT AS A WARM FRONTAL SEGMENT LIFTS
NORTH ACROSS THE AREA.

THE COMBINATION OF AT LEAST SOME RAIN AND MAJOR SNOWMELT WILL BRING
THE RISK FOR SIGNIFICANT FLOODING TO THE LAKE EFFECT AREAS...BOTH
FOR SMALL STREAMS AS WELL AS SOME OF THE LARGER CREEKS AND RIVERS.
THIS WOULD INCLUDE THE BUFFALO AREA CREEKS...CATTARAUGUS CREEK...
AND THE CREEKS THAT DRAIN THE TUG HILL REGION.

LOOKING INTO THE MIDDLE OF THE WEEK FOR THE IMPORTANT THANKSGIVING
HOLIDAY TRAVEL TIME PERIOD...COLDER AIR WILL FILTER BACK INTO THE
GREAT LAKES. BOTH THE GFS AND ECWMF DROP 850MB TEMPS TO -8C TO -10C
BY WEDNESDAY WITH CYCLONIC SOUTHWESTERLY FLOW...SUGGESTING THE
POTENTIAL FOR ANOTHER LAKE EFFECT EVENT. STAY TUNED.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR TO MVFR CONDITIONS WILL BE FOUND REGIONWIDE THIS EVENING AS
LIGHT SNOW WILL MOVE THROUGH AHEAD OF A WARM FRONT.

A COLD FRONT WILL THEN SWEEP ACROSS THE REGION AFTER 03Z. THE
DEEPENING COLD AIR IN ITS WAKE WILL ONCE AGAIN SET THE STAGE FOR
MAJOR LAKE EFFECT SNOWS EAST OF BOTH LAKES. LIFR CONDITIONS WILL BE
FOUND WITHIN THESE BANDS. OFF LK ERIE...THE BAND IS FORECAST TO
DEVELOP NEAR IAG BY ABOUT 03Z. THIS BAND WILL SETTLE SOUTH ACROSS
BUF WHERE IT WILL STALL JUST TO THE SOUTH DURING THE OVERNIGHT
HOURS. LIFR CONDITIONS WILL HOLD IN PLACE FOR MUCH OF THE NIGHT AT
KBUF. THE EASTWARD EXTENT OF THE BAND WILL LIKELY PRODUCE MVFR
CONDITIONS AT KROC.

OFF LK ONTARIO...THE BAND WILL INITIALLY FORM OVER THE THOUSAND
ISLANDS REGION. FROM THERE THE BAND WILL SETTLE SOUTH TO KART WHERE
IT IS FORECAST TO REMAIN IN PLACE THROUGH THE NIGHT AND THE FIRST
HALF OF THURSDAY. AGAIN...LIFR CONDITIONS WILL BE FOUND IN HEAVY
SNOW WITHIN THIS BAND. OUTSIDE OF THESE BANDS...MAINLY VFR
CONDITIONS CAN BE EXPECTED LATE TONIGHT AND THURSDAY...ALTHOUGH SFC
WINDS WILL GUST TO 30 KTS. THIS COULD PRODUCE AREAS OF BLOWING SNOW.

OUTLOOK...
THURSDAY NIGHT...HEAVY LAKE EFFECT SNOW DRIFTING SOUTHWARD TOWARDS
THE KJHW AIRFIELD AND SOUTH OF THE KART AIRFIELD. MAINLY VFR
ELSEWHERE.
FRIDAY...LAKE EFFECT SNOW LIKELY EAST AND SOUTHEAST OF THE LAKES
WITH LOCAL IFR. MAINLY VFR ELSEWHERE.
SATURDAY...VFR.
SATURDAY NIGHT THROUGH MONDAY...PERIODS OF IFR/MVFR IN RAIN AND
GROUND FOG. LLWS POSSIBLE SUNDAY NIGHT AND INTO MONDAY MORNING.

&&

.MARINE...
BEHIND ANOTHER FRESHENING COLD AIRMASS WINDS WILL AGAIN INCREASE ON
THE LAKES WITH GALES EXPECTED ON LAKE ONTARIO LATER TONIGHT AND
THROUGH THE DAY TOMORROW. ELSEWHERE HIGH END SMALL CRAFT ADVISORIES
WILL BE IN PLACE ON LAKE ERIE AND SMALL CRAFTS ON THE RIVERS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WARNING FROM 11 PM THIS EVENING TO 1 AM EST
     FRIDAY FOR NYZ010>012-085.
     LAKE EFFECT SNOW WARNING FROM 3 AM THURSDAY TO NOON EST FRIDAY
     FOR NYZ007-008.
     LAKE EFFECT SNOW WARNING FROM 4 PM THURSDAY TO 6 PM EST FRIDAY
     FOR NYZ006.
     LAKE EFFECT SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 7 PM EST
     THURSDAY FOR NYZ003.
     LAKE EFFECT SNOW WARNING FROM 6 AM THURSDAY TO NOON EST FRIDAY
     FOR NYZ019-020.
     LAKE EFFECT SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 4 AM EST
     FRIDAY FOR NYZ013.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 7 PM EST
         THURSDAY FOR LEZ020.
         SMALL CRAFT ADVISORY UNTIL 8 PM EST FRIDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 7 PM
         EST THURSDAY FOR LOZ030.
         GALE WARNING FROM 1 AM THURSDAY TO 1 AM EST FRIDAY FOR
         LOZ043>045-063>065.
         GALE WARNING FROM 1 AM TO 10 PM EST THURSDAY FOR LOZ042-
         062.
         SMALL CRAFT ADVISORY FROM 7 AM TO 7 PM EST THURSDAY
         FOR SLZ022-024.

&&

$$

SYNOPSIS...RSH/THOMAS
NEAR TERM...RSH/THOMAS
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...RSH/THOMAS
MARINE...THOMAS







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