Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 091823
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
123 PM EST TUE FEB 9 2016

.SYNOPSIS...
WHILE A STALLED STORM SYSTEM OVER THE LOWER GREAT LAKES WILL KEEP
THE REGION SHROUDED UNDER CLOUDS...ONLY LIGHT NUISANCE
PRECIPITATION IS EXPECTED. AS THE SYSTEM STARTS TO MOVE AWAY
TONIGHT...COLDER AIR WILL DEEPEN IN ITS WAKE WITH ACCUMULATING
LAKE SNOWS DEVELOPING EAST OF BOTH LAKES. THESE LAKE SNOWS WILL
PERSIST INTO THE WEEKEND...AT WHICH TIME OUR FIRST TRUE ARCTIC
AIRMASS OF THE SEASON WILL INVADE THE AREA. FRIGID TEMPERATURES
DURING THE DAY SATURDAY WILL HOVER WITHIN A FEW DEGREES OF ZERO
WITH DANGEROUSLY LOW WIND CHILL VALUES.

&&

.NEAR TERM /THROUGH TONIGHT/...
REGIONAL RADARS CONTINUE TO SHOW SOME SCATTERED LIGHT RETURNS WITH A
MIXTURE OF RAIN AND SNOW ACROSS WESTERN NY. ADDITIONALLY...A LITTLE
ENHANCED SHOWER ACTIVITY IS OCCURRING OFF LAKE ERIE. NO ACCUMULATION
IS EXPECTED AT THIS TIME FOR LOWER ELEVATIONS AS TEMPERATURES HAVE
CLIMBED MOSTLY ABOVE THE FREEZING MARK HERE. ELSEWHERE...ACROSS THE
HIGHER TERRAIN OF THE SOUTHERN TIER WHERE TEMPERATURES ARE NEAR OR
BELOW FREEZING A TRACE UP TO A FEW HUNDREDTHS OF AN INCH WILL BE
POSSIBLE MAINLY ON GRASSY SURFACES. FURTHER TO THE EAST AND
NORTHEAST THERE IS SOME WEAK LIFT IN THE VCNTY OF A SLOW MOVING
FRONTAL BOUNDARY. THIS IS HELPING TO GENERATE A LITTLE BETTER
ORGANIZED AREA OF LIGHT SNOW ACROSS THE NORTH COUNTRY
WITH AGAIN VERY MINIMAL ACCUMULATION EXPECTED.

NOW FOR THE BIGGER PICTURE...AN IMPRESSIVE AND HIGHLY AMPLIFIED
SYNOPTIC PATTERN HAS DEVELOPED OVER THE CONTINENTAL U.S WITH A RIDGE
IN THE WEST AND A DEEP TROUGH COVERING 2/3 OF THE EASTERN U.S. IN
ADDITION TO THIS IMPRESSIVE PATTERN...A NEARLY VERTICALLY STACKED
CLOSED LOW HAS SET UP SHOP OVER THE LOWER GREAT LAKES.
HOWEVER...EVEN WITH THIS FEATURE IN PLACE LITTLE TO NO REAL DYNAMICS
REMAIN. THIS HAS AND WILL LIKELY CONTINUE TO RESULT IN JUST A WEALTH
OF CLOUDS COVER AND SOME SPOTTY PRECIPITATION. WHILE THERE WILL
REMAIN A DEEP ENOUGH DENDRITIC SNOW GROWTH AREA WITHIN THE CLOUD
COVER...THE LOWER BOUNDARY LAYER WILL STRUGGLE TO REMAIN COLD ENOUGH
TO SUPPORT PRIMARILY SNOW UNTIL COLDER AIR ARRIVES.

TONIGHT...THE BROAD STORM SYSTEM WILL SLOWLY `OPEN UP` AND DRIFT
EAST TO THE ADIRONDACKS. WHILE GENERAL SYNOPTIC LIFT WILL REMAIN
WEAK UNDER THE DEPARTING SYSTEM...DEEPENING COLD AIR IN ITS WAKE
WILL ESTABLISH ENOUGH LAKE DRIVEN INSTABILITY TO GENERATE SOME
LAKE EFFECT SNOW. THIS MESOSCALE LAKE RESPONSE MAY TAKE MUCH OF
THE NIGHT TO GET GOING THOUGH...AS LAKE DELTA T`S SHOULD NOT REACH
CRITICAL VALUES UNTIL AFTER MIDNIGHT. THE MOST LIKELY AREA FOR
LAKE SNOWS BY DAYBREAK WILL BE ACROSS THE SOUTHERN TIER WHERE A
COUPLE INCHES OF ACCUMULATION WILL BE POSSIBLE ALONG THE
CHAUTAUQUA RIDGE. OUTSIDE OF THIS LAKE EFFECT...THERE WILL ONLY BE
SOME SCATTERED LIGHT SNOW SHOWERS.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
THERE IS NO MAJOR SHIFT IN 12Z GUIDANCE...WITH MESOSCALE GUIDANCE
NOW STARTING TO COME INTO BETTER FOCUS. THE MAIN CHANGE IN FORECAST
IS TO INCREASE SNOW AMOUNTS A BIT SOUTH OF LAKE ONTARIO WHERE THERE
WILL LIKELY BE A BRIEF GEORGIAN BAY CONNECTION WEDNESDAY NIGHT INTO
THURSDAY. NO CHANGES TO WSW HEADLINES YET...WITH THE MAJOR
CONSIDERATION BEING THE TIMING AND LOCATION OF SNOW SOUTH OF LAKE
ONTARIO AS WELL AS THE EXISTING WATCH WHICH IS IN PLACE.

THE PERSISTENT SURFACE LOW WHICH HAS BEEN MEANDERING TO OUR WEST
WILL FINALLY MOVE ACROSS THE LOWER LAKES EARLY WEDNESDAY MORNING
BEFORE RIPPLING DOWN THE INVERTED TROUGH INTO NEW ENGLAND BY
WEDNESDAY AFTERNOON. MOIST CYCLONIC FLOW WILL INCREASE AS THE LOW
MOVES EAST OF OUR LATITUDE...WITH SEVERAL MID LEVEL SHORTWAVES
PROVIDING ADDITIONAL LARGE SCALE ASCENT. THE SYNOPTIC SCALE MOISTURE
AND ASCENT COMBINED WITH LOW LEVEL CONVERGENCE WILL PRODUCE
WIDESPREAD LIGHT SNOW WEDNESDAY AND WEDNESDAY EVENING ACROSS THE
REGION. EXPECT ACCUMULATIONS OF AN INCH OR TWO WEDNESDAY AND ANOTHER
INCH OR TWO WEDNESDAY NIGHT OUTSIDE OF LAKE EFFECT AREAS. BY
THURSDAY THE GENERAL SYNOPTIC SNOW WILL BE COMING TO AND END OUTSIDE
OF LAKE EFFECT AREAS.

AS COLDER AIR FILTERS INTO THE REGION WEDNESDAY LAKE ENHANCEMENT
WILL BECOME A CONCERN...TRANSITIONING INTO MORE PURE LAKE EFFECT
WEDNESDAY NIGHT AND THURSDAY SOUTHEAST OF THE LAKES. LAKE INDUCED
EQUILIBRIUM LEVELS STEADILY RISE ON WEDNESDAY TO AROUND 10K FEET BY
AFTERNOON...AND REMAIN THERE THROUGH THURSDAY AS 850MB TEMPS PLUMMET
TO AROUND -22C.

OFF LAKE ERIE...

INITIALLY WEDNESDAY THIS WILL BE MORE OF A LAKE ENHANCEMENT AND
UPSLOPE SCENARIO WITH DEEP SYNOPTIC SCALE MOISTURE AND ASCENT STILL
IN PLACE. WESTERLY FLOW OFF LAKE ERIE WILL PROVIDE ADDITIONAL
MOISTURE AND SOME INSTABILITY...WITH A STRONG UPSLOPE SIGNATURE
NOTED IN MESOSCALE MODEL GUIDANCE ALONG THE CHAUTAUQUA RIDGE AND THE
BOSTON HILLS.

WEDNESDAY NIGHT THE DEEPER SYNOPTIC SCALE MOISTURE AND ASCENT PULL
AWAY...LEAVING MORE OF A PURE LAKE EFFECT SCENARIO TO UNFOLD.
WESTERLY BOUNDARY LAYER FLOW INITIALLY DURING THE EVENING WILL VEER
NORTHWEST OVERNIGHT. THIS WILL TRANSITION THE LAKE ENHANCEMENT INTO
MULTIPLE BANDS OF LAKE EFFECT SNOW PRIMARILY OVER CHAUTAUQUA AND
CATTARAUGUS COUNTIES AND POSSIBLY STILL CLIPPING FAR SOUTHERN ERIE
COUNTY. UPSLOPE WILL STILL PLAY AN IMPORTANT ROLE...WITH THE HIGHER
SNOWFALL RATES LIKELY FOCUSING ON THE HIGHER TERRAIN JUST INLAND
FROM THE LAKE.

THE SAME PATTERN REMAINS IN PLACE THURSDAY WITH NORTHWEST FLOW
PRODUCING MULTIPLE BANDS OF LAKE EFFECT SNOW ACROSS THE WESTERN
SOUTHERN TIER...WITH GREATER AMOUNTS FOCUSING ACROSS THE HIGHER
TERRAIN JUST INLAND FROM THE LAKE. LATE WEDNESDAY NIGHT AND THURSDAY
THE NEWEST MESOSCALE MODEL GUIDANCE SUGGESTS THE POTENTIAL FOR AN
UPSTREAM CONNECTION TO LAKE HURON. THESE UPSTREAM CONNECTIONS ARE
OFTEN THE KEY TO ACHIEVING A MORE SIGNIFICANT LAKE EFFECT SNOW EVENT
WITH NORTHWEST FLOW OFF LAKE ERIE...WITH NOTABLE CONTRIBUTIONS OF
MOISTURE AND CONVERGENCE COMING FROM THE UPSTREAM LAKE.

GIVEN THE ABOVE EVOLUTION...EXPECT THE HEAVIEST SNOW TO FALL
WEDNESDAY WITH THE LAKE ENHANCEMENT AND UPSLOPE...AND THEN AGAIN
LATER WEDNESDAY NIGHT AND THURSDAY MORNING IF THE UPSTREAM
CONNECTION TO LAKE HURON DEVELOPS. WITH THIS IN MIND...WE WILL GO
WITH A LAKE EFFECT SNOW WATCH FOR CHAUTAUQUA...CATTARAUGUS...AND
SOUTHERN ERIE COUNTIES. THE GREATEST AMOUNTS WILL LIKELY FALL IN A
FAIRLY NARROW CORRIDOR JUST INLAND FROM THE LAKE ALONG THE
CHAUTAUQUA RIDGE WHERE TOTALS FROM LATE TONIGHT THROUGH THURSDAY
AFTERNOON MAY REACH 12-16 INCHES. TOTALS ACROSS THE BOSTON HILLS MAY
ALSO REACH 8-12 INCHES. AMOUNTS WILL BE CONSIDERABLY LOWER ALONG
THE LAKE ERIE SHORE...AND ALSO FARTHER INLAND ACROSS THE WESTERN
SOUTHERN TIER.

OFF LAKE ONTARIO...

LAKE EFFECT WILL BE MUCH SLOWER TO EVOLVE AS THE BOUNDARY LAYER FLOW
WILL BE DISRUPTED WEDNESDAY BY THE CLOSE PROXIMITY OF THE SURFACE
LOW. EXPECT SOME LAKE ENHANCED SNOW TO DEVELOP LATE WEDNESDAY
AFTERNOON AND EVENING EAST OF THE LAKE ACROSS THE TUG HILL AS COLDER
WESTERLY FLOW BECOMES ESTABLISHED. LATER WEDNESDAY NIGHT THROUGH
THURSDAY BOUNDARY LAYER FLOW BECOMES WNW...ALLOWING MORE PURE LAKE
EFFECT SNOW TO DEVELOP SOUTHEAST OF THE LAKE.

MESOSCALE MODEL GUIDANCE SUGGESTS THE LAKE EFFECT SNOW WILL SPREAD
OUT WITH MULTIPLE BANDS ALONG MUCH OF THE SOUTH SHORE FROM NIAGARA
COUNTY EAST TO OSWEGO COUNTY. THE 290 FLOW WOULD SUGGEST A RELATIVE
MAXIMUM IN SNOWFALL COVERAGE AND INTENSITY ACROSS WAYNE AND NORTHERN
CAYUGA COUNTIES EXTENDING INTO THE SYRACUSE AREA. FARTHER WEST SNOW
SHOWERS WILL ALSO IMPACT THE ROCHESTER AREA. THE CURRENT MESOSCALE
MODEL GUIDANCE SUGGESTS THE UPSTREAM CONNECTION WITH GEORGIAN BAY
WILL END UP ACROSS THE NIAGARA FRONTIER LATE WEDNESDAY NIGHT AND
THURSDAY. SINCE THE UPSTREAM CONNECTION IS NOT FORECAST TO LINK UP
WITH THE BETTER LAKE ONTARIO BANDING ACROSS WAYNE/NORTHERN CAYUGA
COUNTIES...IT APPEARS WATCH/WARNING CRITERIA IS LESS LIKELY OFF LAKE
ONTARIO.

EXPECT SNOWFALL AMOUNTS FROM WEDNESDAY MORNING THROUGH THURSDAY
AFTERNOON OF 2-4 INCHES IN GENERAL ALONG THE SOUTH SHORE OF LAKE
ONTARIO. THE SOMEWHAT BETTER BANDING ACROSS WAYNE AND NORTHERN
CAYUGA COUNTIES MAY PRODUCE 4-7 INCHES. THE WILDCARD IS THE GEORGIAN
BAY BAND...WHICH MAY PRODUCE A FEW LOCALLY HIGHER AMOUNTS TO THE
WEST OF ROCHESTER.

TEMPERATURES WILL CONTINUE THEIR DOWNWARD SLIDE WITH EARLY DAY HIGHS
ON WEDNESDAY IN THE LOWER 30S ACROSS LOWER ELEVATIONS AND MID TO
UPPER 20S ON THE HILLS. TEMPERATURES WILL DROP DURING THE AFTERNOON
AS COLD ADVECTION INCREASES IN THE WAKE OF THE DEPARTING LOW. BY
THURSDAY HIGHS WILL ONLY BE IN THE MID TEENS ACROSS LOWER ELEVATIONS
AND LOWER TEENS ON THE HILLS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LAKE EFFECT SNOW WILL WEAKEN INITIALLY THURSDAY EVENING AS A NARROW
SURFACE RIDGE BRIEFLY CROSSES THE LOWER LAKES AND BRINGS INCREASED
SHEAR AND DRY AIR. LATER THURSDAY NIGHT INTO FRIDAY MORNING BOUNDARY
LAYER FLOW WILL BACK MORE WESTERLY...WITH LAKE EFFECT SNOW POSSIBLY
BECOMING BETTER ORGANIZED AGAIN EAST OF THE LAKES.

FRIDAY AFTERNOON THE ARCTIC COLD FRONT WILL APPROACH...THE CROSS THE
REGION FRIDAY EVENING. THE ARCTIC FRONT ITSELF WILL PRODUCE A FEW
SNOW SHOWERS AND POSSIBLY A SNOW SQUALL. EXPECT LAKE EFFECT SNOW TO
INTENSIFY EAST OF THE LAKES JUST AHEAD OF THE ARCTIC FRONT POSSIBLY
PRODUCING DECENT ACCUMULATIONS...THEN MOVE SOUTH OVERNIGHT AND BREAK
APART INTO MULTIPLE BANDS SOUTH OF THE LAKES AS BOUNDARY LAYER FLOW
BECOMES NORTHERLY. LAKE EFFECT SNOW WILL THEN CONTINUE SOUTH OF THE
LAKES SATURDAY THROUGH SUNDAY AS TRUE ARCTIC AIR POURS ACROSS THE
LOWER LAKES. THE INSTABILITY WILL BE EXTREME WITH SUCH A COLD
AIRMASS...BUT ALL AIRMASSES THIS COLD ARE ALSO VERY DRY. THE DRY
AIR...SHORT NORTHERLY FETCH...AND POOR CLOUD MICROPHYSICS IN THE
BITTERLY COLD AIR WILL LIKELY KEEP ACCUMULATIONS RELATIVELY MINOR
FOR SATURDAY THROUGH SUNDAY.

THE BIG STORY THIS WEEKEND WILL BE THE EXTREME COLD. MEDIUM RANGE
GUIDANCE REMAINS CONSISTENT IN BRINGING THE COLDEST AIRMASS OF THE
WINTER BY FAR INTO THE LOWER LAKES AND NEW ENGLAND. BOTH THE GFS AND
ECMWF TAKE 850MB TEMPS DOWN TO AROUND -32C ON SATURDAY. 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. THIS FRIGID AIRMASS WILL KEEP
HIGHS IN THE LOWER SINGLE NUMBERS ON SATURDAY...AND IF THE TIMING
WORKS OUT WITH THE CORE OF THE COLD CROSSING DURING THE DAY HIGHS
MAY NOT GET ABOVE ZERO. LOWS SATURDAY NIGHT WILL BE BELOW ZERO
EVERYWHERE...AND 20 BELOW OR BETTER ACROSS THE NORTH COUNTRY WITH NO
LAKE INFLUENCE. THE COMBINATION OF BITTER COLD AND WIND WILL PRODUCE
DANGEROUSLY COLD WIND CHILLS.

THE CORE OF THE COLD BEGINS TO MOVE OFF BY SUNDAY AFTERNOON WITH A
RAPID WARM-UP TO NEAR AVERAGE BY MONDAY. THE NEXT SYSTEM WILL
APPROACH BY MONDAY WITH A CHANCE OF ANOTHER GENERAL LIGHT SNOW.


&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
PRIMARILY MVFR CIGS WILL CONTINUE THE REST OF THE AFTERNOON FOR
WESTERN NY...WITH SLOWLY DETERIORATING CONDITIONS TOWARD IFR
OVERNIGHT AND/OR WEDNESDAY.  EAST OF LAKE ONTARIO HOWEVER...EXPECT A
PERIOD OF IMPROVING/VFR CONDITIONS AFTER AN AREA OF SNOW MOVES
NORTHEAST OUT OF THE REGION...BEFORE IFR CONDITIONS RETURN LATER
WEDNESDAY.

OUTLOOK...
WEDNESDAY THROUGH THURSDAY...MVFR/IFR IN PERIODS OF SNOW.
FRIDAY...MVFR. A CHANCE OF SNOW SHOWERS.
SATURDAY AND SUNDAY...VFR/MVFR...CHANCE OF SNOW SHOWERS.

&&

.MARINE...
A BROAD...STATIONARY STORM SYSTEM WILL BE CENTERED OVER THE LOWER
GREAT LAKES TODAY. THIS WILL RESULT IN LIGHT TO MODERATE BREEZES
THIS MORNING...THEN AS WE PROGRESS THROUGH THE MIDDAY AND
AFTERNOON...SOUTHWEST WINDS WILL FRESHEN ON LAKE ERIE. WINDS AND
WAVES WILL LIKELY REACH SCA LEVELS ON LK ERIE BY LATE AFTERNOON...
AND WILL CERTAINLY BE IN PLACE TONIGHT. MEANWHILE WINDS WILL REMAIN
RELATIVELY LIGHT ON LAKE ONTARIO.

ON WEDNESDAY...THE LARGE STORM SYSTEM WILL PUSH EAST ACROSS NEW
ENGLAND AND THE CANADIAN MARITIMES. THIS WILL PROMOTE FRESH TO
STRONG WESTERLIES ON BOTH LAKES ERIE AND ONTARIO...WHICH WILL BECOME
MORE NORTHWESTERLY WEDNESDAY NIGHT. A SCA WILL BE NEEDED TO BE
ISSUED FOR LK ONTARIO IN A LATER FORECAST PACKAGE.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WATCH FROM 1 AM EST WEDNESDAY THROUGH
     THURSDAY AFTERNOON FOR NYZ019-020-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EST THURSDAY FOR LEZ040-041.

&&

$$

SYNOPSIS...AR/RSH
NEAR TERM...AR/RSH
SHORT TERM...APFFEL/HITCHCOCK
LONG TERM...APFFEL/HITCHCOCK
AVIATION...AR/RSH
MARINE...AR/RSH



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