Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 110405
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1105 PM EST WED FEB 10 2016

.SYNOPSIS...
LAKE EFFECT SNOWS WILL CONTINUE SOUTH AND EAST OF THE GREAT LAKES
TONIGHT INTO THURSDAY WHILE A SURFACE TROUGH SLOWLY DROPS SOUTH FROM
LAKE ONTARIO. BEHIND THIS TROUGH A PROGRESSIVELY COLDER ARCTIC
AIRMASS WILL OVERSPREAD THE REGION INTO THE WEEKEND. THE MOST FRIGID
CONDITIONS AND DANGEROUSLY COLD WIND CHILLS ARE EXPECTED FRIDAY
NIGHT THROUGH SATURDAY AND SATURDAY NIGHT ALONG WITH ANOTHER PERIOD
OF LAKE EFFECT SNOW EAST OF THE LAKES.

&&

.NEAR TERM /THROUGH THURSDAY/...
A NEARLY STEADY STATE LAKE EFFECT BAND REMAINS IN PLACE ALONG THE
SOUTHERN SHORE OF LAKE ONTARIO. THIS BAND WILL REMAIN IN PLACE
THROUGH THE NEXT FEW HOURS...DROPPING SEVERAL MORE INCHES ALONG THE
NIAGARA/ORLEANS/MONROE SHORELINE NORTH OF 104. THE HEAVIER ACTIVITY
IS EXPECTED TO SHIFT EASTWARD LATER TONIGHT AS A SHARPLY AMPLIFIED
SHORTWAVE CURRENTLY MOVING INTO WESTERN NEW YORK MOVES EAST OVERNIGHT
...CONSEQUENTLY SHIFTING THE FOCUS OF SYNOPTIC LIFT EASTWARD WHILE
CONVERGENT LOW LEVEL WESTERLY FLOW REMAINS IN PLACE. GIVEN THE
IMPRESSIVE LOCALIZED SNOWFALL AMOUNTS OF BETWEEN 1 AND 2 FEET THAT
HAVE ALREADY BEEN REPORTED...SEVERAL MORE INCHES WILL NOT BE OUT OF
THE QUESTION...THOUGH IT IS WORTH NOTING THAT RADAR TRENDS HAVE
INDICATED THAT THE BAND HAS WEAKENED FROM ITS ZENITH EARLIER THIS
EVENING AND THIS WEAKER STRUCTURE SHOULD BE THE GENERAL RULE FOR THE
REST OF THE NIGHT AS FLOW BECOMES INCREASINGLY DISRUPTED WITH THE
APPROACHING SHORTWAVE.

OFF OF LAKE ERIE...THE ROBUST LES ACTIVITY SEEN EARLIER THIS EVENING
IS FINALLY DISSIPATING AS THE UPPER LEVEL TROUGH AXIS MOVES
OVERHEAD. HOWEVER...LES SHOULD RE-ESTABLISH ON WNW FLOW ACROSS
EXTREME SOUTHERN ERIE COUNTY AND CHAUTAUQUA/CATTARAUGUS COUNTIES AS
THE BACK EDGE OF THE SHORTWAVE SLIDES THROUGH. WHILE EQUILIBRIUM
LEVELS REMAIN ABOVE 10KFT...THE BULK OF THE MOISTURE WILL BE FOUND
AROUND/BELOW 5KFT. WHILE THIS ALONG WITH THE MULTIBAND NATURE OF THE
TYPICAL NORTHWEST FLOW LES EVENTS WILL LIMIT SNOWFALL RATES...THE
PROLONGED WINDOW OF FAVORABLE CONDITIONS LASTING THROUGH TOMORROW
AFTERNOON MEANS THAT AN ADDITIONAL 5 TO 10 INCHES WILL BE POSSIBLE
ACROSS THE WESTERN SOUTHERN TIER WITH HIGHEST AMOUNTS LIKELY ON THE
CHAUTAUQUA RIDGE.

AS ELUDED TO ABOVE...FAVORABLE LAKE EFFECT SNOW CONDITIONS WILL
REMAIN IN PLACE THROUGH THURSDAY...THOUGH ACTIVITY ON LAKE ONTARIO
WILL TRANSITION FROM THE SINGLE BAND STRUCTURE SEEN THIS EVENING TO
MULTI-BANDED ACTIVITY ON WNW FLOW. AS USUAL HIGHEST AMOUNTS WILL
LIKELY BE FOUND TO THE SE OF LAKE ONTARIO WHERE THE LONGEST FETCH
AND UPSTREAM CONNECTION TO GEORGIAN BAY WILL BE MOST PREVALENT. OFF
OF LAKE ERIE...A SIMILAR UPSTREAM CONNECTION TO LAKE HURON SHOULD
SUSTAIN LIGHT TO MODERATE SNOWFALL THROUGH MUCH OF THE DAY ACROSS
THE WESTERN SOUTHERN TIER AND EXTREME SOUTHERN ERIE COUNTY.

THE WIDESPREAD SNOWFALL WILL BE ACCOMPANIED BY FALLING TEMPERATURES
ACROSS THE FORECAST AREA AS THE UPPER LEVEL SHORTWAVE MOVES OVERHEAD
AND INCREASINGLY COLD AIR FILTERS ACROSS THE LOWER GREAT LAKES ON
THE BACKSIDE OF THE WAVE. TEMPERATURES WILL CONTINUE TO FALL THROUGH
THE TEENS TONIGHT WITH MOST AREAS SEEING LOWS IN THE LOW TEENS TO
HIGH SINGLE DIGITS. THE GUSTY WINDS ACCOMPANYING THE SHORTWAVE
PASSAGE WILL PUSH WIND CHILLS INTO THE SINGLE DIGITS BELOW ZERO.
TEMPERATURES WILL BARELY BUDGE ON THURSDAY AS 850MB TEMPS WILL
CONTINUE TO PLUNGE WITH HIGHS GENERALLY AROUND 10 TO 15 WITH SINGLE
DIGITS IN THE NORTH COUNTRY AND THE HILLTOPS OF THE SOUTHERN TIER.
CONTINUED GUSTY WINDS WILL MAKE IT FEEL PARTICULARLY RAW WITH WIND
CHILLS REMAINING BELOW ZERO.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
FOR THE EVENING UPDATE WE HAVE EXPANDED THE LAKE EFFECT SNOW WATCH
FOR LATE THURSDAY NIGHT AND INTO FRIDAY...TO NOW INCLUDE
WYOMING...NORTHERN ERIE AND GENESEE COUNTIES. DETAILS BELOW...

AN UPPER LEVEL TROUGH AXIS WILL EXIT EAST INTO NEW ENGLAND THURSDAY
NIGHT THEN ANOTHER SHORTWAVE AND WEAK SURFACE LOW WILL APPROACH ON
FRIDAY. THIS WILL SHIFT WINDS FROM THE WNW THURSDAY EVENING TO THE
SW BY FRIDAY WHICH WILL LIFT LAKE EFFECT SNOW BANDS NORTHWARD.

OFF LAKE ERIE...LIMITED MOISTURE AND SHEAR FROM THE SHIFTING FLOW
SHOULD DISRUPT LAKE SNOWS THURSDAY EVENING...BUT BY FRIDAY MORNING
FORECAST WIND FIELDS SUGGEST A FAIRLY WELL ALIGNED SW/250 FLOW.
INITIALLY MOISTURE WILL BE LIMITED...BUT WITH THE APPROACH OF THE
LOW AND LONG FETCH DOWN THE LAKE EXPECT A FAIRLY CONSOLIDATED AND
INTENSE LAKE EFFECT BAND TO DEVELOP. CONSENSUS HIGH RESOLUTION
GUIDANCE REFLECTS THESE TRENDS...BUT SUSPECT THAT THE CONSENSUS
PLACES THE BAND TOO FAR SOUTH AND INLAND. THIS IS BECAUSE THE WSW
925MB FLOW TENDS TO FUNNEL UP THE CHAUTAUQUA RIDGE WHICH WOULD FOCUS
THE HEAVIEST SNOWS ACROSS SOUTHERN ERIE AND FAR NORTHERN CHAUTAUQUA
COUNTY...OR THE SOUTH TOWNS TO SKI COUNTRY WITH 6 TO 10 INCHES A
POSSIBILITY IF THE BAND DEVELOPS AS EXPECTED. THE RGEM HAS THE BEST
HANDLE ON THIS.

BOTH THE GFS AND NAM SUGGEST STRONG CONVERGENCE SHOULD CONTINUE TO
LIFT NORTHWARD TO NORTHERN ERIE COUNTY. WITH STILL GOOD LAKE EFFECT
PARAMETERS COMING FROM AN OPEN LAKE FREE OF ICE...WITH EQUILIBRIUM
LEVELS UP TO 10K FEET WITHIN A WELL ALIGNED SOUTHWEST FLOW FRIDAY
MORNING A MODERATE BAND OF LAKE EFFECT SNOW WILL BECOME LIKELY OVER
NORTHERN ERIE COUNTY...WITH THE BAND POSSIBLY EXTENDING INLAND ALSO
ACROSS WYOMING AND GENESEE COUNTIES. AS SUCH WILL EXPAND THE LAKE
EFFECT SNOW WATCH TO INCLUDE WYOMING...NORTHERN ERIE AND GENESEE
COUNTIES AS WELL.

BY FRIDAY AFTERNOON THE APPROACHING SHORTWAVE SHOULD
INCREASE SHEAR AND RESULT IN A MORE DIFFUSE AREA OF LAKE EFFECT SNOW
WHICH WILL PRODUCE A LARGER AREA OF MODERATE SNOWS WHICH COULD BRING
A COUPLE INCHES.

OFF LAKE ONTARIO...THE MOST TRICKY PART OF THE FORECAST IS THURSDAY
EVENING WHEN THERE IS A WELL ALIGNED AND FAIRLY STRONG WNW FLOW
FORECAST ACROSS THE LAKE. AS THIS FLOW DIMINISHES A BIT THERE IS A
POTENTIAL FOR THIS TO CONSOLIDATE INTO A NARROW BUT INTENSE BAND.
HOWEVER...THIS FAVORABLE ENVIRONMENT WILL ONLY LAST FOR 3-6
HOURS...THEN SHEAR WILL INCREASE AS THE WINDS SHIFT TO THE SOUTHWEST
AND LIFT THE BAND QUICKLY NORTHWARD. MOST MESOSCALE GUIDANCE ONLY
SHOWS A BRIEF AND FAIRLY TRANSIENT BAND. THIS LOWERS FORECAST
CONFIDENCE A BIT...BUT WITH THE LONG FETCH AND FORECAST WIND FIELDS
THERE STILL APPEARS TO BE A FEW HOURS OF INTENSE SNOW SOUTHEAST OF
THE LAKE FROM WAYNE TO OSWEGO COUNTY. AFTER THIS...A WELL ALIGNED
SOUTHWESTERLY FLOW IS FORECAST TO DEVELOP SIMILAR TO LAKE ERIE. THIS
WILL NOT ONLY TAP INTO MOISTURE FROM THE APPROACHING SHORTWAVE...BUT
ALSO MOISTURE FROM WHATEVER FORMS ON LAKE ERIE. THIS PROVIDES AMPLE
CONFIDENCE TO ISSUE A LAKE EFFECT SNOW WATCH FOR JEFFERSON COUNTY
WITH A POTENTIAL OF SIGNIFICANT SNOW ON FRIDAY FOR WATERTOWN AND
VICINITY. CONSENSUS 850MB TEMPERATURES ARE STILL AROUND -16C AND THE
EQUILIBRIUM LEVEL IS FORECAST TO DEEPEN TO NEARLY 15K FT AND A
FAVORABLY DENDRITIC SNOW GROWTH ZONE. GIVEN THESE INGREDIENTS IN
PLACE...WOULD NOT BE SURPRISED IF SOME LOCATIONS TOPPED A FOOT OF
SNOW. LAKE EFFECT SNOW MAY CLIP NORTHERN LEWIS COUNTY...BUT FOR NOW
EXPECT ADVISORY TYPE AMOUNTS.

ON FRIDAY EVENING A POWERFUL ARCTIC FRONT WILL SURGE SOUTH ACROSS
THE REGION. 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 THE EASTERN LAKE ONTARIO 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. THE FRONT
WILL ALSO USHER IN BITTERLY COLD TEMPERATURES WHICH WILL BE BELOW
ZERO IN MOST AREAS BY DAYBREAK SATURDAY.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A FRIGID ARCTIC AIRMASS WILL TAKE HOLD OF THE EASTERN GREAT LAKES
AND NEW ENGLAND THIS WEEKEND. A CONSENSUS OF 12Z GUIDANCE DROPS
850MB TEMPERATURES TO AROUND -30C AT BUFFALO DURING THE DAY AT
BUFFALO...WITH -33C ACROSS THE EASTERN LAKE ONTARIO REGION. 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.

THIS WILL RESULT IN BITTERLY COLD TEMPERATURES DURING THE DAY
SATURDAY WITH DAYTIME TEMPERATURES STRUGGLING TO RISE ABOVE ZERO.
DAYTIME HIGHS WILL ALMOST CERTAINLY BE BELOW ZERO IN THE EASTERN
LAKE ONTARIO REGION. PERSISTENT WINDS OF 10 TO 15 MPH ON SATURDAY
NIGHT WILL LIMIT RADIATIONAL COOLING...BUT EVEN SO IT WILL BE VERY
COLD WITH BELOW ZERO LOWS REGION-WIDE. LOWS OF -20F OR COLDER ARE
POSSIBLE 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. 12Z GUIDANCE IS A
BIT FASTER MOVING THE SURFACE RIDGE ACROSS THE REGION...WITH LAKE
EFFECT SNOW LIKELY TO TAPER OFF BY SUNDAY NIGHT.

AFTER THIS THERE IS GENERAL MODEL AGREEMENT THAT TEMPERATURES WILL
WARM BACK TO NEAR NORMAL EARLY NEXT WEEK. HOWEVER...THE 12Z ECMWF
IS SIGNIFICANTLY DIFFERENT FROM THE GFS/GGEM. THE ECMWF HAS
CONSISTENTLY DEVELOPED A STRONG WAVE OF LOW PRESSURE WITH
SIGNIFICANT QPF ACROSS OUR REGION WHICH WOULD FALL AS RAIN OR
SNOW. THE GGEM/GFS HAVE THIS SYSTEM BUT KEEP IT WELL TO OUR
EAST...AND INSTEAD ARE A BIT COLDER WITH A CHANCE FOR LIGHT SNOW
SHOWERS. THE FORECAST WILL REFLECT A CONSENSUS BETWEEN THIS
GUIDANCE...WITH NEAR NORMAL TEMPERATURES AND CHANCE POPS.

&&

.AVIATION /04Z THURSDAY THROUGH MONDAY/...
AN UPPER LEVEL DISTURBANCE APPROACHING THE REGION IS ENHANCING LAKE
EFFECT SNOW BANDS ALREADY IN PLACE ACROSS THE AREA...RESULTING IN
SNOW BANDS ALONG THE SOUTHERN SHORE OF LAKE ONTARIO AND EAST OF LAKE
ERIE. WHILE IFR/LIFR CONDITIONS ARE EXPECTED WITHIN THESE
BANDS...MVFR TO VFR CONDITIONS WILL BE FOUND OUTSIDE OF LES
ACTIVITY.

EXPECT LES ACTIVITY TO SHIFT OVERNIGHT AS FLOW VEERS TO THE WNW.
THIS SHOULD BRING A RETURN OF IFR CONDITIONS TO KJHW/KROC LATER
TONIGHT WHILE VFR TO MVFR CONDITIONS SHOULD PREVAIL AT
KBUF/KIAG/KART...WHICH SHOULD REMAIN OUTSIDE OF THE BULK OF LES
ACTIVITY. LES ACTIVITY SOUTH AND SOUTHEAST OF THE LAKES IS EXPECTED
TO PREVAIL INTO THE EARLY AFTERNOON HOURS BEFORE TAPERING OFF BY 00Z
FRI AS SURFACE RIDGING THEN BRIEFLY MOVES OVERHEAD.
OTHERWISE...EXPECT GUSTY WNW WINDS TO REMAIN A FACTOR THROUGH THE
REST OF THE FORECAST PERIOD.

OUTLOOK...
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...CHANCE OF IFR/MVFR IN WEAKENING LAKE EFFECT SNOW SHOWERS
SOUTH OF THE LAKES.
MONDAY...MAINLY VFR. A CHANCE OF SNOW SHOWERS.

&&

.MARINE...
A BRISK FLOW OF PROGRESSIVELY COLDER ARCTIC AIR WILL CONTINUE TO
OVERSPREAD THE REGION THROUGH THE WEEKEND...RESULTING IN A PROLONGED
PERIOD OF ADVISORY-WORTHY WINDS AND WAVES ACROSS THE LOWER LAKES
ALONG WITH THE POTENTIAL FOR MODERATE FREEZING SPRAY.

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 EVEN MORE HEIGHTENED
POTENTIAL FOR HEAVY FREEZING SPRAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WATCH FROM LATE THURSDAY NIGHT THROUGH LATE
     FRIDAY NIGHT FOR NYZ007.
     LAKE EFFECT SNOW WARNING UNTIL 4 AM EST FRIDAY FOR NYZ004>006.
     LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THURSDAY FOR
     NYZ001>003-019-020-085.
     LAKE EFFECT SNOW WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
     EVENING FOR NYZ012-019-020-085.
     LAKE EFFECT SNOW WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
     EVENING FOR NYZ010-011.
     LAKE EFFECT SNOW ADVISORY UNTIL 4 AM EST THURSDAY FOR NYZ013.
     LAKE EFFECT SNOW WARNING UNTIL 4 AM EST THURSDAY FOR NYZ012.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR
         LOZ042>045.

&&

$$

SYNOPSIS...SMITH
NEAR TERM...WOOD
SHORT TERM...APFFEL/THOMAS
LONG TERM...APFFEL
AVIATION...WOOD
MARINE...JJR/SMITH


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