Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 282045
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
345 PM EST WED JAN 28 2015

.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL CONTINUE TO BRING FAIR WEATHER AND
CLEAR SKIES THROUGH THIS EVENING. A WEATHER SYSTEM WILL APPROACH ON
THURSDAY SPREADING CLOUDS ACROSS THE AREA BY MORNING...AND SNOW
ACROSS THE AREA BY THE AFTERNOON...AND WILL TAPER OFF BY FRIDAY
MORNING. SNOW ACCUMULATIONS WILL BE ELEVATION DEPENDENT AND WILL
RANGE FROM A COUPLE INCHES ALONG THE LAKE PLAINS TO 3 TO 6 INCHES
ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND THE TUG HILL.
ANOTHER AREA OF HIGH PRESSURE WILL BRING FAIR WEATHER FRIDAY INTO
SATURDAY. THEN ANOTHER CHANCE FOR WIDESPREAD SNOW COMES FOR SUNDAY
INTO MONDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
WITH THIS UPDATE...HAVE ADDED A WINTER WEATHER ADVISORY FOR PORTIONS
OF THE WESTERN SOUTHERN TIER AND THE EASTERN LAKE ONTARIO
REGION...FOR SNOW FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING.

HIGH PRESSURE OVER THE UPPER OHIO RIVER VALLEY WILL CONTINUE TO
SHIFT EASTWARD ACROSS THE AREA THROUGH TONIGHT. SKIES WILL REMAIN
MOSTLY CLEAR THROUGH THIS EVENING WITH ONLY A FEW HIGH THIN CLOUDS
PASSING BY. TEMPERATURES WILL FALL QUICKLY THIS EVENING WITH LIGHT
WINDS AND CLEAR SKIES IN PLACE...ESPECIALLY ACROSS THE NORTH COUNTRY
WHERE THE AXIS OF THE SURFACE HIGH WILL BE CENTERED BRINGING NEAR
CALM CONDITIONS. TEMPERATURES WILL FALL INTO THE SINGLE DIGITS BELOW
ZERO IN THE NORTH COUNTRY. FROM ROCHESTER BACK ACROSS WESTERN NEW
YORK...SOUTHEASTERLY WINDS WILL START TO DEVELOP BY LATER IN THE
NIGHT AHEAD OF THE APPROACHING SHORTWAVE FOR THURSDAY. SOME MID AND
HIGH LEVEL CLOUDS WILL START TO PUSH ACROSS WESTERN NEW YORK BY
THURSDAY MORNING. THE COMBINATION OF THESE INCREASING CLOUDS AND
WINDS ACROSS WESTERN NY WILL KEEP TEMPERATURES ON THE POSITIVE SIDE
OF ZERO. LIKE LAST NIGHT... LOW TEMPERATURES WILL LIKELY RANGE
SIGNIFICANTLY WITH RURAL AREAS AND VALLEY LOCATIONS SEEING THE
COLDER TEMPERATURES PUSHING CLOSER TO ZERO...AND URBAN AREAS LIKE
BUFFALO AND ROCHESTER MAY STRUGGLE TO GET MUCH BELOW 10 DEGREES.

DURING THE DAY THURSDAY...ATTENTION TURNS TO THE APPROACHING SERIES
OF SHORTWAVES THAT WILL COMBINE TO PRODUCE A WIDESPREAD SYNOPTIC
SNOW EVEN ACROSS THE AREA FROM THURSDAY AFTERNOON THROUGH FRIDAY
MORNING. THE SHORTWAVES ARE CURRENTLY SEEN ON WV IMAGERY 1/
ENTERING NEBRASKA 2/ ENTERING MONTANA AND 3/ FARTHER NORTH INTO
ALBERTA. AS THE WAVES CONSOLIDATE AND APPROACH THE FORECAST AREA
TONIGHT...AN ELONGATED SURFACE LOW WILL DEVELOP OVER THE UPPER
GREAT LAKES AND MOVE ACROSS THE FORECAST AREA THURSDAY NIGHT.

INITIALLY THURSDAY MORNING THROUGH NOON TIME...A WEAK WARM FRONTAL
FEATURE ASSOCIATED WITH THE FIRST WEAK SHORTWAVE SHOULD DEVELOP A
LINE OF WEAK SNOW SHOWERS OR FLURRIES THAT MOVES ACROSS THE FORECAST
AREA. THIS FEATURE IS FAIRLY SUBTLE...BUT LATEST HIGH RES NMM/ARW
MODELS ALONG WITH THE NAM AND SREF PICK IT OUT AND GENERATE SOME
VERY LIGHT QPF. THE QPF FOR THIS FEATURE IS LIKELY OVERDONE...AS
FORECAST SOUNDINGS SHOW QUITE A BIT OF LOW-LEVEL DRY AIR TO OVERCOME
BEFORE ANY PRECIPITATION COULD REACH THE GROUND. HAVE DECIDED TO
ADVERTISE THIS FEATURE AS A CHANCE FOR SOME FLURRIES IN THE MORNING
AHEAD OF THE MAIN SYSTEM APPROACHING FOR THE AFTERNOON. IN REALITY
THIS MAY ONLY MANIFEST AS AN AREA OF VIRGA THAT CROSSES THE FORECAST
AREA...BUT CERTAINLY CANNOT RULE OUT SOME FLURRIES OR VERY LIGHT
SNOW SHOWERS.

BY THURSDAY AFTERNOON...MORE SIGNIFICANT QG FORCING MOVES INTO WESTERN
NEW YORK AS THE WAVE AXIS MOVES ACROSS MICHIGAN. HOWEVER...WARM AIR
ADVECTION AND DOWNSLOPE FLOW AHEAD OF THE WAVE WILL PUSH SURFACE
TEMPERATURES ALONG THE LAKE PLAIN INTO THE LOW 30S...LIKELY A DEGREE
OR TWO ABOVE FREEZING. THE HIGHER ELEVATION OF THE SOUTHERN TIER
WILL BE ENOUGH TO KEEP SURFACE TEMPERATURES RIGHT ABOUT FREEZING.

LOWER ELEVATIONS FROM DUNKIRK TO BUFFALO TO BATAVIA...
AS SNOW DEVELOPS ACROSS WESTERN NEW YORK THURSDAY AFTERNOON...LOWER
ELEVATIONS LIKE DUNKIRK NORTH TO BUFFALO METRO AREA AND ACROSS TO
BATAVIA WILL LIKELY BE JUST A LITTLE TO WARM TO SEE THE SNOW STICK
WELL. HAVE CUT BACK SNOW RATIO SIGNIFICANTLY FOR THESE AREAS...AND
SNOW AMOUNTS BY RUSH HOUR THURSDAY COULD RANGE FROM NOTHING IF
TEMPERATURES ARE JUST A DEGREE OR TWO WARMER THAN EXPECTED...TO A
SLUSHY HALF INCH OR INCH IF THE TEMPERATURES RUN JUST A DEGREE OR
TWO COLDER THAN EXPECTED. THE MOST LIKELY SCENARIO IS THAT
TEMPERATURES WILL BE JUST A LITTLE ABOVE FREEZING...AND THUS THE
EVENING COMMUTE THURSDAY WILL JUST BE WET WITH HARDLY ANY IMPACT.
HOWEVER...THERE IS SOME UNCERTAINTY AS TO HOW QUICKLY TEMPERATURES
COOL WITH THE ONSET OF PRECIPITATION...SHOULD THEY COOL MORE QUICKLY
THAN EXPECTED...THEN THE EVENING COMMUTE COULD BECOME A LITTLE SLICK
ESPECIALLY FOR UNTREATED ROADS.

ROCHESTER...
ROCHESTER WILL LIKELY NOT SEE MUCH IN THE WAY OF SNOW BY 6PM
THURSDAY...AS A SLIGHTLY SLOWER TREND IN THE ARRIVAL OF THE WAVE
COMBINED WITH DOWNSLOPE FLOW WILL PROBABLY HOLD OFF THE SNOW START
TIME TIL LATE AFTERNOON. THE DOWNSLOPE FLOW WILL FURTHER EXACERBATE
THE PROBLEM OF PRECIPITATION OVERCOMING THE LOW-LEVEL DRY AIR IN
PLACE AHEAD OF THE SYSTEM. EVEN THEN...SNOW COULD START  FALLING BY
RUSH HOUR...BUT TEMPERATURES WILL PROBABLY REMAIN MARGINAL MAKING IT
TOUGH FOR MUCH SNOW TO STICK INITIALLY.

WESTERN SOUTHERN TIER...
WITH THE EXPECTATION THAT TEMPERATURES IN THE HIGHER ELEVATIONS WILL
STRUGGLE TO MAKE IT ABOVE FREEZING ON THURSDAY...ONCE SNOW DEVELOPS
EARLY THURSDAY AFTERNOON EXPECT IT SHOULD START STICKING FAIRLY
QUICKLY. HAVE GONE WITH SNOW RATIOS OF 10-12 TO 1 IN THESE COLDER
AREAS...WHICH MATCHES WELL WITH THE COBB METHOD...WHICH DOES FAIRLY
WELL IN SYNOPTIC SNOW. BY THE EVENING COMMUTE...EXPECT 1 TO 2 INCHES
OF SNOW COULD BE ON THE GROUND...ESPECIALLY ACROSS CHAUTAUQUA AND
CATTARAUGUS COUNTIES...INCLUDING JAMESTOWN...WHERE THE SNOW WILL
ARRIVE THE EARLIEST. AMOUNTS SHOULD DROP OFF VERY QUICKLY JUST DOWN
THE CHAUTAUQUA RIDGE...INCLUDING THE THRUWAY...WITH THE WARMER
TEMPERATURES AT THE LOWER ELEVATIONS.

EASTERN LAKE ONTARIO...CURRENT CONSENSUS IN TIMING SUGGESTS THE SNOW
WILL JUST BE ARRIVING IN TIME FOR THE EVENING COMMUTE. FORECAST
TEMPERATURES AT THAT TIME ARE RIGHT ABOUT FREEZING...AND THUS EXPECT
SNOW SHOULD NOT TAKE LONG TO START STICKING.

SNOW WILL CONTINUE ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY...SEE
THE SHORT TERM DISCUSSION BELOW.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
A PROGRESSIVE MID LEVEL TROUGH WILL CROSS THE REGION THURSDAY NIGHT
AND FRIDAY...WITH A LEAD VORTICITY MAXIMA AND ASSOCIATED SURFACE LOW
PASSING OVER THE REGION THURSDAY NIGHT. THE SURFACE LOW IS STILL
FORECAST TO PASS JUST NORTH OF LAKES ERIE AND ONTARIO...WITH A
SURFACE COLD FRONT CROSSING THE CWA FROM WEST TO EAST OVERNIGHT. THE
INITIAL PUSH OF SNOW ASSOCIATED WITH ISENTROPIC UPGLIDE AHEAD OF THE
SYSTEM WILL MOVE INTO THE NORTH COUNTRY DURING THE EVENING...WITH
ANOTHER PERIOD OF ASCENT SUPPORTED BY CONVERGENCE ALONG THE COLD
FRONT AND MID LEVEL DPVA OVERNIGHT. MOST MODEL GUIDANCE CONTINUES TO
LOOK OVERDONE WITH QPF GIVEN THE TRACK OF THE SURFACE LOW TO OUR
NORTH. THE ONE EXCEPTION IS ACROSS THE HIGHER TERRAIN TO THE SOUTH
OF BUFFALO WHERE A BOOST FROM UPSLOPE FLOW DURING THE SECOND HALF OF
THURSDAY NIGHT INTO FRIDAY MORNING WILL PROVIDE STRONGER ASCENT. THE
SAME UPSLOPE ENHANCEMENT IS ALSO LIKELY TO OCCUR ACROSS THE TUG HILL
REGION THURSDAY NIGHT.

GIVEN THE EXPECTATION OF LESS QPF THAN MODEL GUIDANCE ACROSS LOWER
ELEVATIONS...AND THE FACT THAT THE LAKE PLAINS WILL STILL BE NEAR
FREEZING DURING THE EVENING WITH POOR SNOW/WATER RATIOS...WILL
CONTINUE TO AIM LOW ON SNOWFALL WITH TOTALS OF 1-3 INCHES ACROSS
MOST OF THE LOWER ELEVATIONS FROM THURSDAY AFTERNOON THROUGH EARLY
FRIDAY MORNING. THE HIGHER TERRAIN SOUTH OF BUFFALO SHOULD GET A
GOOD DEAL MORE...DUE TO COOLER TEMPERATURES DURING THE FIRST HALF OF
THE EVENT LEADING TO BETTER ACCUMULATIONS...AND THEN UPSLOPE
ENHANCEMENT DURING THE SECOND HALF OF THE EVENT. THE SAME SHOULD BE
TRUE FOR THE TUG HILL REGION EAST OF LAKE ONTARIO. BOTH OF THESE
AREAS MAY SEE TOTALS IN THE 4-6 INCH RANGE. THE LOWER ELEVATIONS
EAST OF LAKE ONTARIO MAY SEE 2-4 INCH AMOUNTS AS WELL WITH SOMEWHAT
COOLER TEMPERATURES THROUGH THE EVENT COMPARED TO POINTS FARTHER
SOUTH AND WEST. WITH THIS IN MIND WE HAVE HOISTED A WINTER WEATHER
ADVISORY FOR SOUTHERN ERIE/WYOMING/CHAU/CATT COUNTIES AND ALSO THE
EASTERN LAKE ONTARIO REGION.

ON FRIDAY THE SURFACE LOW WILL QUICKLY MOVE ACROSS NEW ENGLAND AND
YIELD TO SECONDARY CYCLOGENESIS OVER THE GULF OF MAINE. STRONG COLD
ADVECTION WILL DEVELOP IN THE WAKE OF THIS SYSTEM LATE THURSDAY
NIGHT AND FRIDAY WITH TEMPERATURES DROPPING THROUGH THE TEENS AND
INTO THE SINGLE NUMBERS ON FRIDAY. THE COMBINATION OF DROPPING
TEMPERATURES AND BRISK WINDS MAY PRODUCE WIND CHILL ADVISORY
CRITERIA WIND CHILLS IN MANY AREAS LATE FRIDAY THROUGH SATURDAY
MORNING...WITH WARNING CRITERIA NOT OUT OF THE QUESTION ACROSS THE
NORTH COUNTRY.

THE COLD NORTHWEST FLOW WILL SUPPORT A WIDE SWATH OF WEAK MULTIPLE
BAND LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO...WITH SOME
ACROSS THE WESTERN SOUTHERN TIER AS WELL FROM UPSLOPE FLOW AND
LIMITED MOISTURE FROM LAKE HURON AND THE FEW OPEN PATCHES ON LAKE
ERIE. DESPITE THE VERY COLD AIRMASS...THE SHORT FETCH...LACK OF
UPSTREAM CONNECTIONS...AND RELATIVELY LOW INVERSION HEIGHTS AROUND
6K FEET WILL LIMIT INTENSITY. THIS MAY PRODUCE ANOTHER 1-2 INCHES OF
ACCUMULATION ON FRIDAY SOUTHEAST OF BOTH LAKES...WITH THE HIGHER
AMOUNTS LIKELY TO BE FOUND FROM THE EASTERN SUBURBS OF ROCHESTER TO
OSWEGO COUNTY GIVEN THE WIND DIRECTION. THE LAKE EFFECT SNOW SHOWERS
WILL CONTINUE FRIDAY NIGHT SOUTHEAST OF THE LAKES...ESPECIALLY OFF
ONTARIO WITH SOME ADDITIONAL VERY MINOR ACCUMULATIONS FROM ROCHESTER
TO OSWEGO COUNTY. THE LAKE EFFECT SNOW SHOWERS WILL FINALLY COME TO
AND END BY MIDDAY SATURDAY AS A SURFACE RIDGE CRESTS OVER THE LOWER
LAKES.

THE SURFACE HIGH WILL PROVIDE A RETURN TO MAINLY DRY WEATHER FOR
SATURDAY AFTERNOON AND SATURDAY NIGHT. TEMPERATURES WILL REMAIN WELL
BELOW AVERAGE SATURDAY WITH HIGHS ONLY IN THE TEENS IN MOST AREAS
AND SINGLE NUMBERS ACROSS THE NORTH COUNTRY.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
12Z MODEL GUIDANCE HAS MADE SOME MAJOR FLIPS WITH RESPECT TO THE
HANDLING OF THE SYSTEM FOR SUNDAY AND MONDAY. BOTH THE ECMWF AND GFS
HAVE ESSENTIALLY LOST THE SYSTEM...WITH A WEAK/FLAT WAVE PASSING
MAINLY TO OUR SOUTH. THIS IS IN STARK CONTRAST TO SOME PREVIOUS RUNS
WHICH SHOWED A SIGNIFICANT SNOW EVENT AS A MODERATELY STRONG LOW
MOVED FROM THE OHIO VALLEY TOWARDS SOUTHERN NEW ENGLAND. THE 12Z
CANADIAN GEM HAS MAINTAINED THE SYSTEM...AND 8 OUT OF 12 GEFS
ENSEMBLE MEMBERS STILL HAVE THE SYSTEM WHICH MAKES THE 12Z GFS AND
ECMWF SOLUTIONS SEEM QUESTIONABLE. GIVEN THE SUPPORT FROM THE GEFS
ENSEMBLE MEAN AND CANADIAN GEM...WE ARE NOT READY TO ABANDON THE
IDEA OF ACCUMULATING SNOW SUNDAY AND MONDAY. WILL BACK OFF JUST A
LITTLE FROM LOW LIKELY POPS TO HIGH CHANCE AND WAIT FOR BETTER RUN
TO RUN MODEL CONSISTENCY BEFORE ADJUSTING FURTHER EITHER UP OR
DOWN.

REGARDLESS OF WHETHER THE SYSTEM MATERIALIZES OR NOT...ANOTHER
STRONG PUSH OF COLD AIR WILL ARRIVE EARLY NEXT WEEK. IF THE
NON-STORM 12Z GFS AND ECMWF ARE CORRECT...THE COLD WOULD ARRIVE
EARLIER ON SUNDAY NIGHT AND MONDAY. IF THE STORM DOES
MATERIALIZE...THE COLDEST AIR WOULD BE DELAYED UNTIL MONDAY NIGHT
AND TUESDAY. COLD AIR REMAINS THROUGH MIDWEEK AND THERE WILL BE AT
LEAST SOME LAKE EFFECT POTENTIAL SOUTHEAST AND EAST OF LAKE
ONTARIO...BUT GIVEN THE MODEL DIFFERENCES BEFORE THAT...THERE IS
TOO MUCH UNCERTAINTY FOR ANY TIMING AND INTENSITY DETAILS YET.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
VFR FLIGHT CONDITIONS WILL CONTINUE THIS EVENING UNDER CLEAR SKIES
AND LIGHT WINDS THANKS TO HIGH PRESSURE BUILDING EAST FROM OHIO. MID
AND HIGH LEVEL CLOUDS WILL WORK EAST ACROSS WESTERN NEW YORK LATE
TONIGHT AHEAD OF THE NEXT STORM SYSTEM APPROACHING OUR REGION.

ON THURSDAY...SNOW WILL DEVELOP FROM WEST TO EAST ACROSS THE AREA.
EXPECT CIGS AND VIS TO DETERIORATE TO IFR BY THURSDAY AFTERNOON FOR
KBUF/KIAG/KJHW...AND BY THURSDAY EVENING FOR KROC/KART.

OUTLOOK...
FRIDAY...A CHANCE OF SNOW SHOWERS ESPECIALLY SOUTHEAST OF THE LAKES.
SATURDAY...NO SIGNIFICANT WEATHER EXPECTED.
SUNDAY AND MONDAY...INCREASING CHANCE FOR IFR CONDITIONS IN SNOW.

&&

.MARINE...
LIGHT WINDS AND CLEAR SKIES WILL PREVAIL THIS EVENING ACROSS OUR
REGION AS HIGH PRESSURE BUILDS EAST FROM OHIO. THE WIND DIRECTION
WILL SLOWLY BACK TO THE SOUTH THURSDAY WITH WAVES BUILDING ON THE
NORTH SIDE OF LAKE ONTARIO. THURSDAY NIGHT WINDS VEER BACK TO
NORTHWESTERLY WITH A CHANCE FOR SMALL CRAFT ADVISORY CONDITIONS
AGAIN.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 5 PM THURSDAY TO 10 AM EST FRIDAY
     FOR NYZ006>008.
     WINTER WEATHER ADVISORY FROM 1 PM THURSDAY TO 10 AM EST FRIDAY
     FOR NYZ012-019-020-085.
MARINE...NONE.

&&

$$

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







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