Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 252046
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
346 PM EST SUN JAN 25 2015

.SYNOPSIS...
LOW PRESSURE WILL MOVE THROUGH THE OHIO VALLEY AND MID ATLANTIC
LATER TONIGHT THROUGH MONDAY AND SPREAD A STEADY LIGHT SNOW INTO
MUCH OF THE REGION EXCEPT THE NORTH COUNTRY. THIS WILL PRODUCE MINOR
ACCUMULATIONS IN MOST AREAS BEFORE TAPERING OFF TO SCATTERED SNOW
SHOWERS EARLY TUESDAY. A STRONG LOW ALONG THE EAST COAST MAY PRODUCE
SOME LIGHT SNOW EAST OF LAKE ONTARIO TUESDAY AND TUESDAY NIGHT BUT
WILL OTHERWISE MISS OUR REGION. HIGH PRESSURE WILL BRING A BRIEF
BREAK ON WEDNESDAY BEFORE ANOTHER LOW BRINGS A WIDESPREAD SNOW ON
THURSDAY.

&&

.NEAR TERM /THROUGH MONDAY/...
VISIBLE SATELLITE IMAGERY SHOWING LAKE EFFECT CLOUDS QUICKLY
DISSIPATING THIS AFTERNOON WITH DRY AIR AND SUBSIDENCE TAKING ITS
TOLL. HIGH PRESSURE WILL CONTINUE TO BUILD EAST ACROSS SOUTHERN
ONTARIO AND QUEBEC TONIGHT WITH A RIDGE EXTENDING DOWN TO LAKE
ONTARIO AND THE NORTH COUNTRY. THIS WILL ALLOW FOR SOME BRIEF
CLEARING THIS EVENING IN ALL AREAS EXCEPT THE WESTERN SOUTHERN TIER
BEFORE MID/HIGH CLOUDS BEGIN TO INCREASE AGAIN FROM SOUTHWEST TO
NORTHEAST OVERNIGHT.

THE BRIEF CLEARING AND COLDER AIRMASS WILL ALLOW MANY AREAS TO DROP
INTO THE SINGLE NUMBERS THIS EVENING WHILE THE SOUTHERN TIER SHOULD
STAY IN THE TEENS WITH THICKER CLOUD COVER. THE NORTH COUNTRY WILL
BE MUCH COLDER WITH CLEAR SKIES LASTING LONGER AND A COLDER AIRMASS
IN PLACE. EXPECT LOWS OF 5 TO 10 BELOW ZERO THERE. WIND CHILLS MAY
GET CLOSE TO ADVISORY CRITERIA ACROSS JEFFERSON AND LEWIS COUNTIES
FOR A SHORT TIME LATE TONIGHT AND EARLY MONDAY...BUT IT APPEARS
WINDS MAY BECOME LIGHT ENOUGH TO KEEP THE NUMBERS JUST SHY OF
CRITERIA.

OUR ATTENTION OTHERWISE TURNS TO A SYNOPTIC SYSTEM FORECAST TO MOVE
FROM THE OHIO VALLEY TONIGHT TO THE MID ATLANTIC MONDAY BEFORE
REDEVELOPING OFF THE EAST COAST MONDAY EVENING IN A CLASSIC MILLER
TYPE-B EAST COAST CYCLOGENESIS EVOLUTION. AS THE LOW MOVES THROUGH
THE OHIO VALLEY TONIGHT A WING OF WARM ADVECTION WILL INCREASE AHEAD
OF THE LOW OVER PA AND PUSH NORTHWARD INTO THE WESTERN SOUTHERN
TIER. INCREASING ISENTROPIC UPGLIDE WILL SUPPORT THE DEVELOPMENT OF
LIGHT SNOW RIGHT ALONG THE PA STATE LINE AS EARLY AS LATE THIS
EVENING...THEN SPREAD NORTH INTO SOUTHERN ERIE/WYOMING COUNTIES AND
THE WESTERN FINGER LAKES BY DAYBREAK MONDAY. EXPECT AROUND AN INCH
OVERNIGHT ACROSS THE WESTERN SOUTHERN TIER WITH CLOSER TO 2 INCHES
POSSIBLE RIGHT ALONG THE PA STATE LINE.

ON MONDAY THE SURFACE LOW WILL CONTINUE INTO WEST VIRGINIA THEN JUMP
TO OFFSHORE OF THE VIRGINIA CAPES AS LARGE SCALE ASCENT AND DPVA
OVERSPREAD THE COASTAL FRONT AND FORCE LOW LEVEL CYCLOGENESIS. A
BROAD AREA OF WARM ADVECTION WILL CONTINUE TO OVERSPREAD MOST OF OUR
REGION...WITH WEAK TO MODERATE ISENTROPIC UPGLIDE AND WEAK
STRETCHING DEFORMATION SUPPORTING PERSISTENT ASCENT. THE ISENTROPIC
UPGLIDE WILL BE SUPPORTED BY A MODEST 30-35 KNOT SOUTHERLY LOW LEVEL
JET FROM THE WESTERN SOUTHERN TIER INTO THE GENESEE VALLEY AND
FINGER LAKES WHICH WILL PROVIDE SOME ADDED LIFT AND CONVERGENCE. A
BROAD MID LEVEL TROUGH WILL PROVIDE SOME LARGE SCALE SUPPORT AS
WELL...ALTHOUGH THE STRONGEST DPVA BY FAR WILL BE DIRECTED TOWARDS
THE MID ATLANTIC COAST.

THE SNOW WILL REACH THE NYS THRUWAY CORRIDOR FROM BUFFALO TO
ROCHESTER BY MID MORNING...THEN SPREAD NORTH TO THE SOUTH SHORE OF
LAKE ONTARIO BY LATE MORNING. A PERSISTENT NORTHEAST FEED OF DRY AIR
ACROSS THE NORTH COUNTRY SHOULD KEEP MOST OF THE SNOW AT BAY ACROSS
JEFFERSON AND LEWIS COUNTIES WITH JUST THICKENING MID LEVEL CLOUDS.

EXPECT ADDITIONAL AMOUNTS OF 2-3 INCHES ON MONDAY FROM THE WESTERN
SOUTHERN TIER INTO SOUTHERN ERIE/WYOMING COUNTIES AND EAST INTO THE
GENESEE VALLEY AND WESTERN FINGER LAKES. AMOUNTS WILL LIKELY BE
LOWER ACROSS THE NIAGARA FRONTIER AND TAPER QUICKLY TOWARDS SOUTHERN
OSWEGO COUNTY WITH 1-2 INCH AMOUNTS THERE ON THE EDGE OF THE
STEADIER SHIELD OF SNOW. THIS WILL PRODUCE TOTALS FROM TONIGHT INTO
MONDAY OF AROUND 4 INCHES ACROSS THE WESTERN SOUTHERN TIER...WITH
2-3 INCHES FROM SOUTHERN ERIE/WYOMING COUNTIES INTO THE GENESEE
VALLEY AND WESTERN FINGER LAKES...AND 1-2 INCHES ACROSS THE NIAGARA
FRONTIER AND SOUTHERN OSWEGO COUNTY. TOTALS OF AROUND 4 INCHES
ACROSS THE WESTERN SOUTHERN TIER FIT IN PERFECTLY WITH THE TRIED AND
TRUSTED GARCIA METHOD...WITH ABOUT 12 HOURS OF ISENTROPIC LIFT AND
ABOUT 2G/KG OF SPECIFIC HUMIDITY NEAR THE 700MB LAYER SUPPORTING
ABOUT 4 INCHES OF ACCUMULATION. AMOUNTS LOOK TOO MARGINAL FOR AN
ADVISORY AT THIS TIME...AND WILL FALL OVER A LITTLE LONGER PERIOD
THAN THE 12 HOUR ADVISORY CRITERIA.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A STRONG COASTAL STORM JUST EAST OF SOUTHERN NEW ENGLAND WILL BE
SHIFTING NORTHWARD OFF THE COAST MONDAY NIGHT WITH AN INVERTED
SURFACE TROUGH EXTENDING TO THE WEST OF THE STORM ACROSS PA/WNY.
WHILE THE LARGEST IMPACTS FROM THE STORM WILL OCCUR WELL EAST OF OUR
FORECAST AREA...A COMBINATION OF THE SURFACE TROUGH AND
LAKE-ENHANCED NORTHERLY FLOW ACROSS WESTERN NEW YORK WILL CONTINUE
TO PRODUCE SOME LIGHT SNOW ACCUMULATIONS. 12Z BUFKIT PROFILES SHOW A
MORE FAVORABLE TEMPERATURE AND MOISTURE PROFILE ALOFT ACROSS ALL OF
WESTERN NEW YORK WHICH REMOVES THE THREAT FOR ANY FREEZING DRIZZLE.

AS THE COASTAL STORM SHIFTS JUST EAST OF CAPE COD ON TUESDAY 12Z
GFS/ECWMF MODELS SHOW THE WESTERN EDGE OF THE STORM CROSSING THE
NORTH COUNTY WHILE THE 12Z NAM KEEPS THIS FURTHER EAST. HAVE GONE
WITH LIKELY POPS FAVORING THE GLOBAL MODELS WHILE FURTHER WEST A
CONTINUING NORTHERLY FLOW ACROSS LAKE ONTARIO WILL KEEP AT LEAST A
CHANCE FOR SOME MORE SNOW ACROSS WESTERN NEW YORK. WEAK LAKE INDUCED
EQUILIBRIUM LEVELS THROUGH THE ENTIRE EVENT REMAIN UNDER 5KFT WITH A
DEEP ISOTHERMAL CAPPING INVERSION ALOFT. THIS ALONG WITH A CROSS
LAKE FETCH WILL KEEP ANY LAKE ENHANCEMENT WEAK. A BLEND OF MODEL QPF
SEEMS COMBINED WITH AN AVERAGE 15:1 SNOW-LIQUID RATIO YIELDS 1-2
INCHES ACROSS FAR WESTERN NEW YORK AND THE NORTH COUNTY WITH 2-3
INCHES FOR THE FINGER LAKES AND GENESEE VALLEY MONDAY NIGHT AT
TUESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL WITH LOWS DIPPING
INTO THE TEENS AND SINGLE DIGITS MONDAY NIGHT ONLY WARMING 5-10
DEGREES ON TUESDAY.

TUESDAY NIGHT THE COASTAL STORM WILL WEAKEN AND BEGIN TO FILL AS ITS
RAPIDLY SHIFTS TO THE CANADIAN MARITIMES. SNOW WILL TAPER OFF WEST
TO EAST. WEDNESDAY A NARROW WEDGE OF SURFACE RIDGING EXTENDING NORTH
ACROSS NEW YORK BEHIND THE COASTAL STORM SHOULD BRING DRY WEATHER
AND SOME DECENT SUNSHINE. AFTER A COLD NIGHT WITH TEMPS IN THEN
SINGLE DIGITS TUESDAY NIGHT...SOME WEAK WARMING ALOFT WILL HELP
BOOST TEMPS TOWARD THE LOW 20S WEDNESDAY...BUT STILL TOPPING OUT
BELOW NORMAL. MUCH OF WEDNESDAY NIGHT SHOULD ALSO REMAIN DRY BUT
WARM ADVECTION AHEAD OF THE NEXT STORM PUSHING TOWARD CHICAGO MAY
BRING A SLIGHT/LOW CHANCE OF LIGHT SNOW BY EARLY THURSDAY.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
GLOBAL MODELS REMAIN IN GOOD AGREEMENT WITH THE NEXT STORM SYSTEM TO
SHIFT ACROSS NEW YORK AND THE LOWER GREAT LAKES IN THE
THURSDAY-FRIDAY TIMEFRAME. THIS LOW CENTER TRACKING JUST SOUTH OF NEW
YORK WITH SUB-FREEZING VERTICAL TEMPERATURE PROFILES WILL FAVOR AN
ACCUMULATING SNOWFALL. DRY AND COLD WEATHER WILL START THE WEEKEND
SATURDAY WITH HIGH PRESSURE AND SHORTWAVE RIDGING PASSING BY THEN
12Z GFS AND ECMWF MODELS DIVERGE WITH TIMING THE ARRIVAL OF THE NEXT
ARCTIC BLAST TO OPEN FEBRUARY. THE 12Z ECMWF SHOWS -25C 850MB AIR
USHERED IN WITH AN ARCTIC FRONT ON SUNDAY/SUNDAY NIGHT WHILE THE 12Z
GFS DELAYS THIS COLDEST AIR UNTIL TUESDAY BEHIND AN EARLY WEEK GREAT
LAKES CUTTER. HAVE FOLLOWED WPC AND SURROUNDING OFFICES KEEPING
TEMPERATURES ON THE COLD SIDE OF GUIDANCE WITH A CHANCE OF SOME SNOW
SUNDAY.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
LAKE EFFECT CLOUDS ARE RAPIDLY DISSIPATING SOUTH OF LAKE ONTARIO
THIS AFTERNOON AS DRIER AIR AND SUBSIDENCE WIN OUT. THIS WILL ALLOW
MOST AREAS TO SEE A RETURN TO VFR FROM LATE AFTERNOON THROUGH THE
EVENING.

LATER TONIGHT SNOW WILL BEGIN TO OVERSPREAD THE WESTERN SOUTHERN
TIER NEAR THE PA STATE LINE...THEN MOVE NORTHWARD TO THE SOUTH SHORE
OF LAKE ONTARIO MONDAY MORNING. ONCE THE LIGHT SNOW BEGINS VSBY WILL
QUICKLY DETERIORATE TO IFR...FIRST ACROSS THE SOUTHERN TIER
INCLUDING KJHW 05Z-07Z...THEN SPREADING NORTH TO KBUF-KROC BY
13Z-15Z. THE LIGHT SNOW WILL THEN CONTINUE THROUGH THE REST OF THE
DAY WITH VSBY VARYING BETWEEN 1-3 MILES. THE SNOW WILL HAVE A SHARP
NORTHERN EDGE...AND PROBABLY NOT REACH THE NORTH COUNTRY INCLUDING
KART THROUGH MONDAY AFTERNOON. CIGS WILL DETERIORATE TO MVFR SHORTLY
AFTER THE ONSET OF SNOW...WITH IFR DEVELOPING ACROSS THE HIGHER
TERRAIN OF THE SOUTHERN TIER AND FINGER LAKES ON MONDAY.

OUTLOOK...
MONDAY NIGHT...AREAS OF MVFR/IFR WITH WIDESPREAD LIGHT SNOW.
TUESDAY...AREAS OF MVFR WITH LIGHT SNOW TAPERING OFF TO FLURRIES.
WEDNESDAY...MAINLY VFR.
THURSDAY...A CHANCE OF SNOW AND ASSOCIATED IFR.
FRIDAY...AREAS OF MVFR WITH A CHANCE OF SNOW SHOWERS AND BRIEF IFR
ESPECIALLY SOUTHEAST OF THE LAKES.

&&

.MARINE...
NORTHEAST WINDS WILL INCREASE LATER TONIGHT AND MONDAY AS LOW
PRESSURE MOVES ACROSS THE OHIO VALLEY AND THEN RE-DEVELOPS OFF THE
EAST COAST...WITH HIGH PRESSURE MOVING EAST ACROSS QUEBEC AND
PRODUCING A MODERATE PRESSURE GRADIENT ACROSS LAKE ONTARIO. THIS
WILL PRODUCE SMALL CRAFT ADVISORY CONDITIONS ALONG THE SOUTH SHORE
OF LAKE ONTARIO FROM ABOUT SODUS BAY WESTWARD FROM LATER TONIGHT
THROUGH AT LEAST MONDAY NIGHT...AND POSSIBLY INTO TUESDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 10 PM EST TUESDAY FOR
         LOZ042-043.
         SMALL CRAFT ADVISORY FROM 4 PM MONDAY TO 10 PM EST TUESDAY
         FOR LOZ044.

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HITCHCOCK
MARINE...HITCHCOCK





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