Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 090244
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
944 PM EST MON FEB 8 2016

.SYNOPSIS...
A WEAK TROUGH WILL MOVE ACROSS THE AREA TONIGHT AND SPREAD A LITTLE
SNOW OVER AREAS GENERALLY WEST OF THE FINGER LAKES. ADDITIONAL
LIGHT SNOW MAY POSSIBLY MOVE INTO THE REGION LATE TUESDAY...WITH
INCREASING CHANCES FOR SNOW ALONG WITH SOME LAKE ENHANCEMENT
SOUTHEAST OF THE LAKES LATE WEDNESDAY THROUGH FRIDAY. A BLAST OF
COLD AIR WILL ARRIVE FOR SATURDAY.

&&

.NEAR TERM /THROUGH TUESDAY/...
AN AMPLIFIED UPPER LEVEL PATTERN IS IN PLACE ACROSS THE
CONTINENTAL US WITH A VERY ANOMALOUS LONGWAVE RIDGE IN THE WEST
AND A DEEPENING LOW IN THE EAST. THIS PATTERN HAS ALREADY
CONTRIBUTED TO A COASTAL SYSTEM MOVING NORTHEAST ALONG THE GULF
STREAM...WITH ANOTHER ONE FORECAST TO DEVELOP ON ITS HEALS ABOUT A
DAY LATER /TUESDAY/. MEANWHILE CLOSER TO HOME...PERSISTENT SURFACE
LOW PRESSURE WILL BE ROUGHLY TIED TO SOUTHERN ONTARIO UNDER THE
LONGWAVE TROUGH. A WEAK TROUGH STRETCHING SOUTH FROM THE SURFACE LOW
WILL EVENTUALLY BE WEAKLY ASSOCIATED WITH THE NEXT COASTAL LOW AS
THE TROUGH PIVOTS ACROSS ACROSS WESTERN NY OVERNIGHT. THIS WILL BE
THE FOCUS FOR WEAK LOW LEVEL CONVERGENCE RESULTING IN SOME LIGHT
PRECIPITATION. OBSERVATIONS CURRENTLY SHOWING A MIX OF RAIN AND
SNOW DEPENDENT ON MOSTLY ABOVE FREEZING TEMPERATURES IN THE
LOWER TO MID 30S. ANY RAIN THIS EVENING WILL CHANGE OVER TO SNOW
AS TEMPERATURES DROP A LITTLE OVERNIGHT TOGETHER WITH WEAK
DYNAMIC COOLING. PROFILES DO NOT SUPPORT ANY TYPE OF FREEZING
PRECIPITATION...AND THAT WHICH DOES FALL FROZEN SHOULD AMOUNT TO
ONLY AN INCH OR SO WHERE IT IS STEADY ENOUGH TO ACCUMULATE.

OVER THE EASTERN LAKE ONTARIO REGION...SNOW IS EXPECTED TO SPREAD
WEST TOWARD OR INTO THIS REGION OVERNIGHT...BUT BEING ON THE
PERIPHERY OF THE COASTAL LOW...ONCE AGAIN EXPECT ONLY MEAGER
ACCUMULATIONS IF ANY. THE DRIEST AREA FOR THE NIGHTTIME PERIOD
SHOULD BE TOWARD THE FINGER LAKES REGION...AT LEAST THROUGH MOST
OF THE NIGHT.

ON TUESDAY...THE SURFACE TROUGH WILL MOVE OVER THE FINGER LAKES
REGION WITH FAR WESTERN NY ON THE DRIER AND SUBSIDENT SIDE. BUT ONCE
AGAIN...FORCING IS LIGHT AND EXPECT LIGHT ACCUMULATIONS...A RENEWED
CHANCE FOR SNOW MAY ARRIVE LATE IN THE DAY FAR WEST. TEMPERATURES
ALOFT ACROSS THE REGION SHOULD BE SLOWLY COOLING WITH
TIME...ALTHOUGH THERE IS A SMALL CHANCE SURFACE TEMPERATURES COULD
EXCEED THE FREEZING MARK...WITH LIGHT SNOW MIXING WITH OR CHANGING
BACK OVER TO RAIN TUESDAY AFTERNOON...WHICH OF COURSE WOULD JUST
LEAD TO WET CONDITIONS WITHOUT LASTING ACCUMULATION.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A COMPLEX PATTERN EVOLUTION WILL UNFOLD THROUGH THE SHORT TERM
PERIOD. A MID LEVEL CLOSED LOW WILL OPEN UP INTO A BROAD TROUGH
TUESDAY NIGHT...WITH A COUPLE LOW AMPLITUDE WAVES MOVING SLOWLY
ACROSS THE GREAT LAKES REGION THROUGH THURSDAY. THIS WILL BRING
PERSISTENT AND OCCASIONALLY SIGNIFICANT SNOW TO THE REGION.

TUESDAY NIGHT THROUGH WEDNESDAY MODEL CONSENSUS FORECASTS THE
ORIGINAL LOW TO TRACK FROM LAKE HURON TO WESTERN LAKE ONTARIO
WEDNESDAY MORNING AND ACROSS THE LAKE DURING THE DAY WEDNESDAY.
AHEAD OF THIS WILL BE A SOUTHWESTERLY FLOW WITH INCREASING MOISTURE
AND 850MB TEMPS OF -8C MARGINALLY COLD ENOUGH TO PRODUCE SOME LIGHT
SNOW SHOWERS NORTHEAST OF LAKE ERIE. THERE ALSO COULD BE LIGHT SNOW
ALONG A WEAK FRONTAL BOUNDARY ACROSS THE NORTH COUNTRY. IN EACH CASE
ANY ACCUMULATION WILL BE VERY LIGHT.

THINGS GET MORE INTERESTING LATE TUESDAY NIGHT AND INTO WEDNESDAY.
BOTH THE SURFACE LOW AND UPPER LEVEL TROUGH ARE FORECAST TO CROSS
THE AREA. THIS WILL PICK UP SOME MOISTURE FROM LAKE ERIE...BUT MORE
IMPORTANTLY IT WILL SHIFT WINDS TO THE WEST IN A MOIST FLOW WHICH
SHOULD RESULT IN UPSLOPE ENHANCEMENT AS THE COLD FRONT PASSES. HIGH
RESOLUTION GUIDANCE IN PARTICULAR (NMM/ARW) CAPTURE THIS WITH A
BURST OF SNOW EXPECTED ACROSS WESTERN PORTIONS OF THE CWA WEDNESDAY
MORNING. THIS WILL WEAKEN AS IT MOVES EASTWARD...WITH LAKE
EFFECT/ENHANCED SNOWS CONTINUING EAST OF LAKE ERIE WEDNESDAY
AFTERNOON. THIS ALSO WILL BRING A ROUND OF STEADIER SNOW EAST OF
LAKE ONTARIO LATE WEDNESDAY AFTERNOON ONCE WINDS SHIFT TO THE WEST
BEHIND THE SURFACE LOW. TEMPERATURES WILL CONTINUE TO TREND STEADILY
COLDER WITH HIGHS IN THE LOWER 30S AT LOWER ELEVATIONS AND MID TO
UPPER 20S ON THE HILLS.

WEDNESDAY NIGHT AND THURSDAY THE INITIAL TROUGH WILL MOVE EAST OF
THE AREA...HOWEVER ANOTHER ONE WILL DROP BEHIND IT AND MOVE ACROSS
THE AREA. WINDS WILL SHIFT TO THE NORTHWEST BEHIND THIS AND USHER IN
COLDER AIR ALOFT (ABOUT -20C AT 850MB) AND ANOTHER ROUND OF LAKE
ENHANCED SNOWS. THE BEST SETUP FOR LAKE ENHANCEMENT ALONG THE
CHAUTAUQUA RIDGE SOUTHEAST OF LAKE ERIE AND ALSO SOUTHEAST OF LAKE
ONTARIO. THE LAKE ENHANCEMENT MAY BRING SEVERAL ADDITIONAL INCHES OF
ACCUMULATION...ESPECIALLY ALONG THE CHAUTAUQUA RIDGE WITH AN ADDED
BOOST FROM UPSLOPE FLOW.  HIGHS THURSDAY WILL BE NOTABLY
COLDER...WITH MID TO UPPER TEENS IN MOST AREAS.

THIS PATTERN POSES A CHALLENGE IN TERMS OF HEADLINES. TOTAL SNOWFALL
OVER THE EXTENDED PERIOD OF TIME TUESDAY NIGHT THROUGH THURSDAY IS
EXPECTED TO RANGE FROM 2-4 INCHES IN MOST AREAS WITH JUST VERY MINOR
AMOUNTS EACH 12 HOUR PERIOD ADDING UP TO MODEST ACCUMULATIONS OVER
TIME. AMOUNTS WILL BE HIGHER SOUTHEAST OF LAKE ERIE WITH ADDED LAKE
ENHANCEMENT AND UPSLOPE FLOW. 2 DAY TOTALS MAY REACH 6-10 INCHES
ALONG THE CHAUTAUQUA RIDGE...POSSIBLY HIGHER IF FLOW ALIGNS FOR A
LONG ENOUGH PERIOD OF TIME. AMOUNTS SE OF LAKE ONTARIO SHOULD
AVERAGE IN THE 3-6 INCH RANGE. CONSIDERED AN ADVISORY (OR WATCH) FOR
PORTIONS OF THE SOUTHERN TIER LATE TUESDAY NIGHT THROUGH THURSDAY
MORNING... BUT THERE IS STILL TOO MUCH UNCERTAINTY WITH RESPECT TO
BOUNDARY LAYER FLOW DIRECTION AND THUS THE EFFICIENCY OF UPSLOPE
FLOW. SOUTHEAST OF LAKE ONTARIO LAKE ENHANCEMENT TOWARDS THE END OF
THE EVENT WEDNESDAY NIGHT AND THURSDAY MAY ALSO BRING HIGHER TOTALS
FROM ROCHESTER TO OSWEGO COUNTY. IN ALL OF THESE CASES THERE IS
SIMPLY TOO WIDE A SPREAD IN FORECAST WIND FIELDS TO SUPPORT ANY OF
THESE HEADLINES EVEN THOUGH THERE IS A POSSIBILITY SNOWFALL WILL
REACH CRITERIA. ADDITIONAL MESOSCALE GUIDANCE WILL ALSO BE HELPFUL
IN PINNING DOWN THE EXACT LOCATION...ESPECIALLY CONSIDERING THAT
UPSTREAM CONNECTIONS WILL HEAVILY INFLUENCE SNOWFALL AMOUNTS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THERE WILL CONTINUE TO BE A COLD WESTERLY FLOW THURSDAY NIGHT AND
FRIDAY...BUT WITH NO SIGNIFICANT SHORTWAVES EXPECTED THIS WILL
PROBABLY RESULT IN PERSISTENT BUT GENERALLY LIGHT ACCUMULATIONS
MOSTLY EAST OF THE LAKES. HIGHS ON FRIDAY SHOULD BE IN THE UPPER
TEENS TO LOWER 20S.

AN ARCTIC FRONTAL BOUNDARY IS FORECAST TO DROP ACROSS THE REGION
FRIDAY NIGHT BRING BITTERLY COLD AIR TO THE REGION FOR THE WEEKEND.
12Z MODEL CONSENSUS CONTINUES TO SUPPORT THIS...WITH INCREASING
CONFIDENCE THAT THIS WILL BE THE COLDEST AIR MASS OF THIS WINTER
SEASON. THE 12Z GFS/GGEM/ECMWF ALL FORECAST 850MB TEMPS TO DROP TO
AROUND -30C AT BUFFALO. TO PUT THIS IN PERSPECTIVE...THE COLDEST
850MB TEMPERATURE EVER RECORDED ON A KBUF SOUNDING IN THE MONTH OF
FEBRUARY IS -28C.

TEMPERATURES MAY STRUGGLE TO RISE ABOVE ZERO FOR MUCH OF SATURDAY.
THE COMBINATION OF FRIGID TEMPERATURES AND WIND MAY PRODUCE
DANGEROUSLY COLD WIND CHILLS LATE FRIDAY NIGHT THROUGH SUNDAY
MORNING.

IN ADDITION...THE PASSAGE OF THE ARCTIC FRONT ON FRIDAY NIGHT IS
LIKELY TO BRING SNOW SHOWERS WITH THE LAKES ENHANCING MOISTURE WITH
THE FRONTAL PASSAGE. THIS WILL POTENTIALLY BRING A BRIEF BUT HEAVY
BURST OF SNOW WITH THE FRONT. THEN BEHIND THIS IT WILL EVOLVE INTO A
MORE PURE LAKE EFFECT EVENT WITH NORTHWESTERLY WINDS CAUSING
PERSISTENT BUT GENERALLY LIGHT LAKE EFFECT SNOW SOUTHEAST OF THE
LAKES WHICH WILL LAST THROUGH MUCH OF THE WEEKEND. THE AIRMASS IS
COLD BUT ALSO VERY DRY WHICH WILL LIMIT SNOW AMOUNTS DESPITE THE
STRONG INSTABILITY.

12Z RUNS OF BOTH THE GFS AND ECMWF START TO BREAK DOWN THIS COLD
PATTERN EARLY NEXT WEEK...BUT DIFFER ON THE TIMING. THE GFS BRINGS A
WAVE WITH A CHANCE OF SNOW SHOWERS ON MONDAY...WITH THE ECMWF ABOUT
A DAY SLOWER. EITHER WAY...IT LOOKS LIKE TEMPERATURES WILL RETURN TO
NORMAL FOR NEXT WEEK.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
CONDITIONS WILL DETERIORATE TO MVFR AND IFR AT TIMES AS A WEAK
SURFACE TROUGH MOVES EASTWARD INTO WESTERN NY. LIGHT SNOW WILL BE
THE PREDOMINANT WEATHER TYPE...WITH SOME RAIN AT FIRST. THIS AREA
OF PRECIPITATION WILL LIKELY REMAIN WEST OF THE FINGER LAKES
REGION. ANOTHER AREA OF SNOW WILL MOVE WEST FROM EASTERN NY AND
POSSIBLY CLIP PORTIONS OF THE EASTERN LAKE ONTARIO LATE TONIGHT
AND TUESDAY MORNING...BUT WILL KEEP KART VFR FOR NOW.

ON TUESDAY...THE ABOVE MENTIONED TROUGH WILL WASH OUT OVER THE
FINGER LAKES...WITH MVFR OR VFR RETURNING FOR WESTERN NY.

OUTLOOK...
TUESDAY NIGHT THROUGH THURSDAY...MVFR/IFR IN PERIODS OF SNOW.
FRIDAY...MVFR. A CHANCE OF SNOW SHOWERS.
SATURDAY...VFR/MVFR...CHANCE OF SNOW SHOWERS.

&&

.MARINE...
A WEAK TROUGH WILL MOVE ACROSS THE REGION TONIGHT WITH EASTERLY
WINDS OVER LAKE ONTARIO AS THE MAIN LOW REMAINS OVER SOUTHERN
ONTARIO. THIS WILL CREATE SMALL CRAFT ADVISORY CONDITIONS FOR THE
WESTERN PORTION OF THE LAKE. WINDS OVER LAKE ERIE WILL ALSO
INITIALLY BE EASTERLY...BUT WILL BECOME SOUTHWESTERLY AFTER THE
TROUGH PASSAGE TUESDAY. ADDITIONAL SCA CONDITIONS WILL BE POSSIBLE
IN THE SW-WSW THROUGH WED.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST TUESDAY FOR LOZ042.

&&

$$

SYNOPSIS...ZAFF
NEAR TERM...TMA/ZAFF
SHORT TERM...APFFEL
LONG TERM...APFFEL/HITCHCOCK
AVIATION...TMA/ZAFF
MARINE...ZAFF


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