Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 100941
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
441 AM EST WED FEB 10 2016

.SYNOPSIS...
LOW PRESSURE OVER LAKE ONTARIO WILL SLIDE EASTWARD INTO NEW
ENGLAND TODAY. IN THE WAKE OF THIS SYSTEM...A PROGRESSIVELY COLDER
ARCTIC AIRMASS WILL OVERSPREAD THE REGION THROUGH THE
WEEKEND...WHILE GENERATING ACCUMULATING LAKE SNOWS TO THE LEE OF
THE GREAT LAKES. THE MOST FRIGID CONDITIONS ARE EXPECTED ON
SATURDAY...WHEN HIGHS WILL LIKELY STRUGGLE TO CLIMB MUCH ABOVE
ZERO...AND WIND CHILLS WILL BE AT DANGEROUSLY LOW LEVELS.

&&

.NEAR TERM /THROUGH TONIGHT/...
LOW PRESSURE OVER LAKE ONTARIO WILL DRIFT EASTWARD INTO NEW
ENGLAND TODAY...WITH A PROGRESSIVELY COLDER ARCTIC-SOURCED AIRMASS
OVERSPREADING OUR REGION TODAY AND TONIGHT. OUTSIDE OF AREAS OF
OROGRAPHICALLY-INDUCED AND LAKE EFFECT SNOWS THAT ARE EXPECTED
EAST AND SOUTHEAST OF THE LAKES WITHIN THE INCOMING COLDER
AIRMASS...THIS SYSTEM WILL BRING CLOUDY SKIES AND A GENERAL LIGHT
SNOWFALL OF A FEW INCHES TO THE REGION TODAY INTO TONIGHT...WHILE
ALSO CONTINUING THE TREND TOWARD COLDER TEMPERATURES.

REGARDING THE AREAS OF ENHANCED SNOWFALL MENTIONED ABOVE...

OFF LAKE ERIE...A GENERAL WESTERLY FLOW ON THE BACKSIDE OF THE
DEPARTING LOW TODAY WILL VEER MORE WEST-NORTHWESTERLY TONIGHT
FOLLOWING THE PASSAGE OF A NOTEWORTHY MID/UPPER LEVEL SHORTWAVE.
UNDER THIS FLOW REGIME...THE STEADIEST LAKE AND TERRAIN-ENHANCED
SNOWS WILL TEND TO FOCUS MOST ACROSS THE CHAUTAUQUA RIDGE REGION
OF SOUTHERN ERIE/CHAUTAUQUA/CATTARAUGUS COUNTIES THROUGH THE NEAR
TERM PERIOD...WITH THE ACTIVITY BECOMING INCREASINGLY LAKE-DRIVEN
OVER TIME AS OUR AIRMASS GROWS COLDER. EXPECT THE HEAVIEST AND
MOST PERSISTENT SNOWS IN THIS REGION TO FALL EARLY THIS MORNING
AND AGAIN TONIGHT...WITH THE MORE SIGNIFICANT SNOWS TONIGHT TIED
TO THE PASSAGE OF THE SHORTWAVE AND THE SUBSEQUENT POTENTIAL
DEVELOPMENT OF AN UPSTREAM CONNECTION TO LAKE HURON LATER ON
TONIGHT. WITH LAKE EQLS OF 8-10 KFT IN PLACE AND FAVORABLE
MOISTURE LYING BELOW THAT...THE STAGE APPEARS SET FOR WARNING-
CRITERIA SNOWFALL AMOUNTS ACROSS THE ABOVE MENTIONED REGION
BETWEEN TODAY AND THURSDAY.

MEANWHILE OFF OF LAKE ONTARIO...LAKE ENHANCED SNOWS WILL TAKE A
LITTLE BIT LONGER TO GET GOING TODAY OWING TO THE PASSAGE OF THE
SURFACE LOW CENTER DIRECTLY ACROSS THAT LAKE...BUT SHOULD FORM
ACROSS THE EASTERN LAKE ONTARIO REGION BY LATER THIS MORNING ON A
SHEARED SOUTHWESTERLY FLOW OUT AHEAD OF THE LOW. AFTER THAT...THE
CORE OF THESE WILL THEN SHIFT SOUTH ACROSS THE TUG HILL AND
EVENTUALLY INTO THE WAYNE-NORTHERN CAYUGA- SOUTHERN OSWEGO COUNTY
CORRIDOR THIS AFTERNOON AND EVENING AS THE LOW LEVEL FLOW BECOMES
BETTER ALIGNED OUT OF THE WEST AND THEN WEST-NORTHWEST FOLLOWING
THE PASSAGE OF THE SURFACE LOW...BEFORE SETTLING EVEN A LITTLE
FURTHER SOUTHWARD LATER TONIGHT FOLLOWING THE PASSAGE OF THE
AFOREMENTIONED SHORTWAVE. AS WITH THE LAKE ERIE ACTIVITY...A
PRETTY FAVORABLE ENVIRONMENT SHOULD BE IN PLACE WITH LAKE EQLS OF
8-10 KFT PRESENT AND SUFFICIENT MOISTURE LYING BELOW THAT TO
RESULT IN A DECENT POTENTIAL FOR WARNING-CRITERIA SNOWFALL AMOUNTS
WHERE THE SNOWS WILL BE MOST PERSISTENT TODAY THROUGH
THURSDAY...WHICH IN THIS CASE APPEARS TO BE THE NORTHEASTERN
WAYNE-SOUTHERN OSWEGO COUNTY CORRIDOR WHERE THE EXISTING LAKE SNOW
ADVISORIES HAVE BEEN UPGRADED TO LAKE EFFECT SNOW WARNINGS.
MEANWHILE ON EITHER SIDE OF THE WARNING AREA...LAKE EFFECT SNOW
ADVISORIES HAVE ALSO BEEN HOISTED FOR THE REMAINDER OF THE TUG
HILL REGION...AND ALSO FOR THE NIAGARA-MONROE COUNTY CORRIDOR
WHERE LESSER BUT STILL ADVISORY-WORTHY AMOUNTS APPEAR LIKELY
BETWEEN TODAY AND THURSDAY...WITH THE FORMER REGION AFFECTED BY
THE DEVELOPING/ SHIFTING LAKE SNOWS TODAY AND THIS EVENING...AND
THE LATTER AREA LIKELY TO BE AFFECTED BY A WESTWARD EXTENSION OF
THE MAIN LAKE ONTARIO LAKE SNOW BAND LATE TODAY AND TONIGHT.

AS FOR TEMPERATURES...EXPECT THESE TO PEAK IN THE UPPER 20S TO
LOWER 30S BETWEEN THIS MORNING AND EARLY THIS AFTERNOON...THEN
STEADILY DROP INTO THE 10-15 RANGE ACROSS MUCH OF THE AREA BETWEEN
THE REMAINDER OF THIS AFTERNOON AND TONIGHT. BY LATE
TONIGHT...READINGS MAY EVEN FALL INTO THE UPPER SINGLE DIGITS
ACROSS PORTIONS OF THE SOUTHERN TIER AND NORTH COUNTRY.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
ON THURSDAY THE SURFACE LOW WILL MOVE EAST INTO THE CANADIAN
MARITIMES WITH THE MID LEVEL TROUGH CROSSING THE LOWER LAKES REGION.
ASCENT AND DEEPER MOISTURE ASSOCIATED WITH THE MID LEVEL TROUGH WILL
PRODUCE A FEW SCATTERED SNOW SHOWERS OUTSIDE OF LAKE EFFECT AREAS...
ESPECIALLY EAST OF LAKE ONTARIO WHERE FORCING WILL BE STRONGEST. THE
MAIN FOCUS THURSDAY AND THURSDAY NIGHT WILL BE WITH THE ONGOING LAKE
EFFECT SNOW SOUTHEAST OF THE LAKES.

OFF LAKE ERIE...

LAKE INDUCED INSTABILITY REMAINS STRONG THROUGH THE PERIOD WITH
EQUILIBRIUM LEVELS AROUND 10K FEET. BOUNDARY LAYER FLOW WILL
CONTINUE TO BE NORTHWEST ON THURSDAY...WHICH WILL LIMIT THE FETCH
ACROSS LAKE ERIE BUT ALSO PROVIDE FAVORABLE UPSLOPE FLOW ALONG THE
CHAUTAUQUA RIDGE. MESOSCALE MODEL GUIDANCE CONTINUES TO SUGGEST AN
UPSTREAM CONNECTION TO LAKE HURON ESPECIALLY DURING THE FIRST HALF
OF THURSDAY. THIS WILL LIKELY ENHANCE SNOWFALL RATES ACROSS PORTIONS
OF CHAUTAUQUA COUNTY...MOST LIKELY THE FAR SOUTHWEST CORNER OF THE
COUNTY NEAR FINDLAY LAKE GIVEN THE FLOW DIRECTION. THIS UPSTREAM
CONNECTION WILL END LATER THURSDAY AFTERNOON AS BOUNDARY LAYER FLOW
BACKS ACROSS SOUTHERN LAKE HURON. THE END OF THE UPSTREAM CONNECTION
AND ALSO A WEAK SURFACE RIDGE BRIEFLY BUILDING OVER LAKE ERIE SHOULD
WEAKEN THE LAKE ERIE LAKE EFFECT LATER THURSDAY AFTERNOON AND
EVENING.

EXPECT ADDITIONAL ACCUMULATIONS OF 3-6 INCHES ON THURSDAY IN
PERSISTENT BANDS ACROSS THE WESTERN SOUTHERN TIER...WITH THE HIGHER
AMOUNTS FOCUSED ON THE UPSLOPE AREAS OF THE CHAUTAUQUA RIDGE AND
ALSO WHERE THE LAKE HURON CONNECTION FORMS. THIS WILL BRING STORM
TOTALS FROM LATE TUESDAY EVENING THROUGH LATE THURSDAY AFTERNOON
INTO THE 12-18 INCH RANGE IN THE MOST PERSISTENT BANDS...MAINLY IN A
RELATIVELY SMALL AREA OF UPSLOPE FLOW JUST INLAND FROM THE
LAKESHORE.

LATER THURSDAY NIGHT AND FRIDAY BOUNDARY LAYER FLOW WILL BACK TO THE
WEST AND EVENTUALLY WSW AS A SURFACE LOW RACES EAST ACROSS SOUTHERN
ONTARIO IN ADVANCE OF THE ARCTIC FRONT. THE BACKING WINDS WILL ALLOW
LAKE EFFECT SNOW TO RE-ORGANIZE LATE THURSDAY NIGHT AS FETCH
INCREASES ACROSS THE LAKE. INSTABILITY REMAINS STRONG THROUGH FRIDAY
WITH EQUILIBRIUM LEVELS AROUND 10K FEET...ALTHOUGH THE AIRMASS MAY
DRY OUT IN THE TOP OF THAT LAYER. EXPECT THE LAKE EFFECT SNOW TO
MAKE IT INTO THE SOUTHERN HALF OF THE BUFFALO METRO AREA FOR A TIME
FRIDAY MORNING...ALSO EXTENDING INTO PORTIONS OF SOUTHERN GENESEE
AND WYOMING COUNTIES. THIS BAND OF SNOW MAY PRODUCE AT LEAST
MODERATE ACCUMULATIONS...WITH UNCERTAINTIES STILL ON THE IMPACT OF
SOMEWHAT DRIER AIR ALOFT AND INCREASING SHEAR WITH THE APPROACH OF
THE ARCTIC FRONT. THIS MAY EVENTUALLY REQUIRE ADDITIONAL LAKE EFFECT
HEADLINES AS THE DETAILS BECOME MORE CERTAIN.

OFF LAKE ONTARIO...

SIMILAR TO LAKE ERIE...LAKE INDUCED INSTABILITY REMAINS STRONG
THROUGH THE PERIOD WITH EQUILIBRIUM LEVELS AROUND 10K FEET. ON
THURSDAY BOUNDARY LAYER FLOW WILL REMAIN NORTHWEST...WITH SNOW ALONG
MUCH OF THE SOUTH SHORE OF THE LAKE. THE 290 WIND DIRECTION SUGGESTS
THERE WILL BE A RELATIVE MAX IN COVERAGE AND INTENSITY ACROSS
WAYNE/NORTHERN CAYUGA/SOUTHERN OSWEGO COUNTIES WHERE THE FETCH IS
MAXIMIZED. MESOSCALE MODEL GUIDANCE CONTINUES TO SUGGEST THE
UPSTREAM CONNECTION TO GEORGIAN BAY WILL RESIDE TO THE WEST OF
ROCHESTER ON THURSDAY. EXPECT ADDITIONAL SNOW AMOUNTS ON THURSDAY OF
3 TO 6 INCHES IN THE MOST FAVORED AREAS OF NORTHERN/EASTERN WAYNE
COUNTY INTO NORTHERN CAYUGA AND FAR SOUTHERN OSWEGO COUNTIES.
FARTHER WEST EXPECT 1 TO 3 INCHES ALONG THE SHORE FROM ROCHESTER TO
PORTIONS OF ORLEANS AND EASTERN NIAGARA COUNTIES. THE WILDCARD IN
THIS AREA IS THE POTENTIAL FOR THE UPSTREAM GEORGIAN BAY CONNECTION
WHICH MAY LOCALLY ENHANCE TOTALS.

THURSDAY NIGHT MAY VERY WELL BE THE TIME OF MOST INTENSE SNOWFALL
FOR A SMALL AREA SOUTHEAST OF LAKE ONTARIO AS THE BAND CONSOLIDATES
WITH BACKING FLOW OVERNIGHT. THE NORTHWEST FLOW WILL BECOME MORE WNW
AND EVENTUALLY WESTERLY...INCREASING FETCH AND CONVERGENCE ALONG THE
LENGTH OF THE LAKE. THIS WILL ALLOW SNOW TO END FROM ROCHESTER
WESTWARD DURING THE EVENING AS THE BAND LIFTS NORTH AND OFFSHORE.
FARTHER EAST...EXPECT AN INTENSIFYING SINGLE BAND OF SNOW OVER
EASTERN WAYNE AND NORTHERN CAYUGA COUNTIES FROM LATE EVENING THROUGH
THE EARLY OVERNIGHT HOURS. TOWARD DAYBREAK FRIDAY BOUNDARY LAYER
FLOW QUICKLY BACKS FURTHER TO WEST AND WSW...WHICH WILL CARRY THE
BAND RAPIDLY NORTHEAST ACROSS OSWEGO COUNTY. ADDITIONAL AMOUNTS
THURSDAY NIGHT SHOULD PEAK FROM SODUS INTO NORTHERN CAYUGA COUNTY
WITH ANOTHER 8-10 INCHES POSSIBLE. EXPECT A QUICK 2-4 INCHES ACROSS
OSWEGO COUNTY LATE THURSDAY NIGHT AS THE BAND MOVES RAPIDLY ACROSS
THE COUNTY.

ON FRIDAY BOUNDARY LAYER FLOW BECOMES ALIGNED FROM THE SOUTHWEST...
WHICH WILL ALLOW THE LAKE EFFECT SNOW TO BECOME BETTER ORGANIZED
AGAIN ACROSS JEFFERSON AND NORTHERN LEWIS COUNTIES. LAKE INDUCED
EQUILIBRIUM LEVELS REMAIN HIGH...ALTHOUGH SHEAR MAY INCREASE WITH
THE APPROACH OF THE ARCTIC FRONT. THIS BAND MAY PRODUCE MODERATE
ACCUMULATIONS NORTHEAST OF LAKE ONTARIO FRIDAY. THIS MAY EVENTUALLY
REQUIRE ADDITIONAL LAKE EFFECT HEADLINES ONCE THE DETAILS BECOME
MORE CERTAIN.

LAST BUT NOT LEAST...A POWERFUL ARCTIC FRONT WILL SURGE SOUTH ACROSS
THE REGION FRIDAY EVENING. THIS ARCTIC FRONT WILL LIKELY CAPTURE AND
MERGE WITH THE LAKE EFFECT SNOW BAND OFF LAKE ONTARIO...WITH A VERY
HEAVY SNOW SQUALL PASSING SOUTH ACROSS MUCH OF THE REGION. THIS WILL
LIKELY PRODUCE AN INCH OR TWO OF SNOW IN MANY AREAS...WITH LOCALLY
HIGHER AMOUNTS SOUTHEAST OF THE LAKES WHERE THE LAKE CONTRIBUTION
MAXIMIZES. BEHIND THE ARCTIC FRONT...MULTIPLE STREAMERS OF LAKE
EFFECT SNOW SHOWERS WILL DEVELOP SOUTH OF THE LAKES LATE FRIDAY
NIGHT AS FLOW BECOMES NORTHWEST AND EVENTUALLY NNW.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
A FRIGID ARCTIC AIRMASS WILL TAKE HOLD OF THE EASTERN GREAT LAKES
AND NEW ENGLAND SATURDAY AS 850MB TEMPS PLUMMET TO AN AVERAGE OF
-32C. TO PUT THIS IN PROSPECTIVE...THE COLDEST TEMPERATURE EVER
RECORDED AT 850MB ON A KBUF SOUNDING IN THE MONTH OF FEBRUARY IS
-28C...AND THE COLDEST EVER RECORDED FOR ANY MONTH IS -32C.
TEMPERATURES WILL DROP INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO BY
EARLY SATURDAY MORNING DEPENDING ON LOCATION. ANY ABOVE ZERO
TEMPERATURES FIRST THING IN THE MORNING WILL LIKELY BE REPLACED BY
SINGLE DIGITS BELOW ZERO EVERYWHERE BY MIDDAY AND AFTERNOON AS THE
CORE OF THE COLDEST AIR ALOFT CROSSES THE AREA. LOWS WILL BE WELL
BELOW ZERO SATURDAY NIGHT...WITH -20 OR BETTER ACROSS THE NORTH
COUNTRY WITH NO MODERATING LAKE INFLUENCE. THE COMBINATION OF
MODERATE WINDS AND FRIGID TEMPERATURES WILL PRODUCE DANGEROUSLY COLD
WIND CHILLS LATE FRIDAY NIGHT THROUGH EARLY SUNDAY MORNING.

THE FRIGID NORTH FLOW OVER THE LAKES WILL PRODUCE WIDESPREAD LAKE
EFFECT SNOW SHOWERS ACROSS WESTERN AND CENTRAL NY. DESPITE THE
EXTREME INSTABILITY...AIRMASSES THIS COLD ARE ALSO VERY DRY AND
TEMPERATURES BECOME TOO COLD FOR DENDRITES. THIS WILL FORCE
SNOWFLAKES TO BE VERY SMALL AND LIMIT ACCUMULATIONS...ALTHOUGH
SEVERAL INCHES ARE LIKELY SOUTH OF BOTH LAKES. THE LAKE EFFECT SNOW
WILL DIMINISH IN COVERAGE AND INTENSITY SUNDAY...BUT NOT END
ALTOGETHER UNTIL SUNDAY NIGHT AS THE HIGH CRESTS OVERHEAD.

THE FRIGID TEMPERATURES WILL BE SHORT LIVED AS STRONG WARM ADVECTION
BRINGS TEMPS BACK TO AVERAGE BY MONDAY AND TUESDAY. THE NEXT
SYNOPTIC SYSTEM WILL MOVE THE REGION BY MONDAY OR TUESDAY WITH A
CHANCE OF SNOW...ALTHOUGH THE GFS AND ECMWF DIFFER A GOOD DEAL ON
THE TIMING AND TRACK DETAILS.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
AS SLOW-MOVING LOW PRESSURE OVER LAKE ONTARIO MOVES EAST OF THE
AREA TODAY...MOISTURE AND AN INCREASINGLY COLD AIRMASS WILL WRAP
ACROSS THE REGION...RESULTING IN THE DEVELOPMENT OF WIDESPREAD
SNOW AND IFR CONDITIONS ACROSS MOST TERMINALS FROM APPROXIMATELY
10-12Z ONWARDS. CONDITIONS ARE EXPECTED TO CONTINUE TO DETERIORATE
TO LIFR ACROSS PORTIONS OF THE WESTERN SOUTHERN TIER AND NORTH
COUNTRY...WHERE WESTERLY WINDS AND LAKE ENHANCEMENT WILL FURTHER
INCREASE SNOWFALL RATES AND REDUCE VISIBILITIES.

TONIGHT...EXPECT MVFR/IFR IN SCATTERED TO NUMEROUS LAKE EFFECT
SNOW SHOWERS...AND IFR/LIFR IN AREAS OF HEAVIER LAKE EFFECT SNOW
EAST- SOUTHEAST OF THE LAKES.

OUTLOOK...
THURSDAY...MVFR/IFR IN SCATTERED TO NUMEROUS LAKE EFFECT SNOW
SHOWERS...AND IFR/LIFR IN AREAS OF HEAVIER LAKE EFFECT SNOW EAST-
SOUTHEAST OF THE LAKES.
FRIDAY...IFR/MVFR WITH SNOW SHOWERS LIKELY...AND AREAS OF HEAVIER
LAKE EFFECT SNOW EAST OF THE LAKES.
SATURDAY...IFR/MVFR IN LAKE EFFECT SNOW SHOWERS SOUTH OF THE LAKES...
WITH MVFR/VFR ACROSS THE NORTH COUNTRY.
SUNDAY...VFR/MVFR WITH IFR/MVFR IN SCATTERED TO NUMEROUS LAKE EFFECT
SNOW SHOWERS SOUTH OF THE LAKES.

&&

.MARINE...
LOW PRESSURE OVER WESTERN LAKE ONTARIO WILL SLIDE EASTWARD INTO
NEW ENGLAND TODAY. IN THE WAKE OF THIS SYSTEM...A BRISK FLOW OF
PROGRESSIVELY COLDER ARCTIC AIR WILL OVERSPREAD THE REGION THROUGH
THE WEEKEND...RESULTING IN A PROLONGED PERIOD OF ADVISORY-WORTHY
WINDS AND WAVES ACROSS THE LOWER LAKES. WITH THIS IN MIND WE HAVE
ELECTED TO EXTEND OUR EXISTING SMALL CRAFT ADVISORIES THROUGH
SATURDAY FOR NOW...THOUGH IT IS QUITE POSSIBLE THAT THESE MAY
EVENTUALLY NEED TO BE EXTENDED EVEN A BIT FURTHER OUT IN TIME.

IN ADDITION TO THE ABOVE...THE PASSAGE OF AN ARCTIC COLD FRONT
FRIDAY EVENING WILL ALSO USHER IN A TRULY FRIGID AIRMASS FOR LATER
FRIDAY NIGHT AND THE UPCOMING WEEKEND...WHICH IN CONJUNCTION WITH
THE EXPECTED BRISK WINDS WILL RESULT IN A GREATLY HEIGHTENED
POTENTIAL FOR HEAVY FREEZING SPRAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
     NYZ007-008.
     LAKE EFFECT SNOW WARNING FROM 10 AM THIS MORNING TO 4 AM EST
     FRIDAY FOR NYZ004>006.
     LAKE EFFECT SNOW ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM EST
     THURSDAY FOR NYZ001>003.
     LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THURSDAY FOR NYZ019-
     020-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 7 PM
         EST SATURDAY FOR LOZ043>045.
         SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
         SATURDAY FOR LOZ042.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...JJR/WOOD
MARINE...JJR


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