Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 260832
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
432 AM EDT THU MAR 26 2015

.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL MOVE ACROSS NEW YORK STATE
TODAY...BRINGING A ROUND OF PRECIPITATION THAT WILL START AS RAIN
THIS MORNING AND TRANSITION TO SNOW THROUGH THE DAY. COLD AIR
ARRIVES FOR FRIDAY INTO SATURDAY...WITH A CHANCE FOR MORE LIGHT SNOW
ACCUMULATIONS FRIDAY NIGHT. HIGH PRESSURE BUILDS INTO THE AREA TO
START NEXT WEEK...AND WILL BRING A SLOW WARMING TREND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AN ELONGATED ZONE OF BAROCLINICITY ORIENTED FROM THE PLAINS NORTH
EAST INTO NEW YORK STATE WILL CONTINUE TO SHARPEN TODAY AS A DIGGING
SHORTWAVE DEEPENS AN UPPER-LEVEL TROUGH ACROSS THE UPPER GREAT
LAKES. THE IMPRESSIVE FRONTOGENESIS AND ISENTROPIC ASCENT ALONG THE
BAROCLINIC ZONE WILL ACT TO FOCUS A BAND OF MODERATE TO HEAVY
PRECIPITATION ACROSS THE STATE TODAY. THE CORE OF STRONGEST
FRONTOGENESIS AND INTEGRATED WV VAPOR TRANSPORT WILL ALIGN ACROSS
CENTRAL NEW YORK AND THE SOUTHERN FINGER LAKES REGION...WHICH IS
WHERE THE HEAVIEST PRECIPITATION WILL FALL. WITH THE BOUNDARY
SETTING UP SLIGHTLY FARTHER EAST THAN PREVIOUSLY FORECAST...EXPECT
TO SEE MORE INFLUENCE FROM THE COLD AIR...WHICH WILL ALLOW
PRECIPITATION TO CHANGE FROM RAIN TO SNOW FROM LATE THIS MORNING
THROUGH THE AFTERNOON. ACCUMULATING SNOW IS NOW EXPECTED ACROSS MUCH
OF THE FORECAST AREA BY THIS AFTERNOON.

QPF AMOUNTS...CONSENSUS QPF AMOUNTS FROM THE
NAM/SREF/GEM/EC/HIRESWRF HAVE DIALED IN ON AROUND THREE QUARTERS OF
AN INCH TO A INCH ALONG THE BAND OF STRONGEST FRONTOGENESIS THROUGH
THE BINGHAMTON CWA. AMOUNTS ARE EXPECTED TO TAPER OFF NORTH AND WEST
OF THIS AXIS TO AROUND A HALF INCH ACROSS MUCH OF OUR FORECAST AREA.
THESE PRECIPITATION AMOUNTS ARE WELL SUPPORTED BY THE GEFS
REFORECAST AND ARE FAIRLY CONSISTENT OVER THE LAST SEVERAL MODEL
CYCLES. THE WESTERN EDGE OF PRECIPITATION SHIELD WILL BE ACROSS
SOUTHERN ONTARIO TODAY AND WILL WORK INTO THE FORECAST AREA FROM THE
NORTHWEST LATE THIS AFTERNOON.

TEMPERATURES/PRECIPITATION TYPE...COOLER SURFACE TEMPERATURES WILL
WORK ACROSS THE FORECAST AREA FROM NORTHWEST TO SOUTHEAST TODAY AS
THE SURFACE LOW TRACKS ACROSS EASTERN NY. TEMPERATURE READINGS THIS
MORNING RANGE FROM THE MID/UPPER 30S ACROSS WESTERN NY TO THE MID
40S ACROSS CENTRAL NY. AS PRECIPITATION OVERSPREADS THE AREA THIS
MORNING...EXPECT IT TO BEGIN AS RAIN. HOWEVER THE COMBINATION OF
DYNAMICAL COOLING AND WEAK LOW-LEVEL CAA THE AIRMASS IS EXPECTED TO
COOL ENOUGH TO SUPPORT A CHANGE OVER TO SNOW BY LATE MORNING ACROSS
NORTHWEST PORTIONS OF THE FORECAST AREA...INCLUDING THE NIAGARA
FRONTIER AND THE WATERTOWN AREA. THE TRANSITION TO SNOW WILL SLOW
WORK SOUTHEASTWARD INTO THE SOUTHERN TIER AND FINGER LAKES REGION
THROUGH THE AFTERNOON AS THE COOLER AIR CONTINUES TO WORK INTO THE
AREA.

SNOW AMOUNTS...GENERALLY 2 TO 4 INCHES OF HEAVY WET SNOW ARE
EXPECTED FOR MUCH OF THE FORECAST AREA...MAINLY ON ELEVATED OR
GRASSY SURFACES. DESPITE THE IMPRESSIVELY HIGH QPF AMOUNTS WITH THIS
SYSTEM...TEMPERATURES ARE EXTREMELY MARGINAL...AND MANY LOCATIONS
WILL SEE SNOW FALLING WITH SURFACE TEMPERATURES RIGHT AT OR JUST
ABOVE FREEZING. THE LATE MARCH SUN ANGLE IS ALSO STRONG ENOUGH TO
WORK AGAINST SNOW ACCUMULATION ON PAVED SURFACES EVEN THROUGH THE
CLOUD COVER. THUS GENERALLY APPLIED SNOW RATIOS OF 5:1 FOR SURFACE
TEMPERATURES ABOVE FREEZING...8:1 AT 32 DEGREES AND 12:1 AT 30
DEGREES OR COLDER.

HYDROLOGY CONCERNS...GIVEN THE OVERALL COOLER TEMPERATURES AND
ANTICIPATING MORE OF THE QPF TO FALL IN FROZEN FORM...FLOODING IS
NOT MUCH OF A CONCERN AT THIS POINT. SEE THE HYDROLOGY SECTION BELOW
FOR MORE DETAILED INFORMATION.

TONIGHT...SNOW WILL TAPER OFF FROM WEST TO EAST AS DRIER AIR
CONTINUES TO WORK IN FROM THE WEST WITH THE WEAK COLD AIR ADVECTION.
TEMPERATURES WILL CONTINUE TO DROP INTO THE UPPER 20S OVERNIGHT.
HOWEVER THE STRONGER COLD FRONT ASSOCIATED WITH THE UPPER-LEVEL LOW
IS NOT EXPECTED TO ARRIVE UNTIL THE DAY ON FRIDAY.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
FRIDAY AND FRIDAY NIGHT A SHARP MID LEVEL TROUGH WILL CROSS THE
LOWER LAKES AND PROVIDE A PERIOD OF LARGE SCALE ASCENT AND DEEPER
WRAP AROUND MOISTURE...WHILE AN EAST/WEST ORIENTED TROUGH AND COLD
FRONT MOVE SLOWLY SOUTH ACROSS THE AREA LATE FRIDAY AND THE FIRST
HALF OF FRIDAY NIGHT...PROVIDING A PERIOD OF ORGANIZED LOW LEVEL
CONVERGENCE. STEADY COLD ADVECTION WILL ALLOW THE AIRMASS TO BECOME
COLD ENOUGH FOR LAKE ENHANCEMENT AS WELL LATE FRIDAY THROUGH EARLY
SATURDAY AS 850MB TEMPS BOTTOM OUT AROUND -16C. THIS WILL SUPPORT
LAKE INDUCED EQUILIBRIUM LEVELS OF AROUND 6K FEET. NORTH TO
NORTHEAST LOW LEVEL FLOW WILL SUPPORT A WIDE AREA OF FAIRLY LIGHT
BUT PERSISTENT LAKE ENHANCEMENT FRIDAY NIGHT FROM NEAR ROCHESTER
WEST ACROSS THE NIAGARA FRONTIER...WITH SOME OF THE MOISTURE
EXTENDING DOWN INTO THE HIGHER TERRAIN OF THE SOUTHERN TIER AND FAR
WESTERN FINGER LAKES AND CONTRIBUTING TO UPSLOPE ENHANCEMENT.

ANY SNOW SHOWERS THROUGH MUCH OF FRIDAY WILL STAY FAIRLY
DISORGANIZED WITH LITTLE ACCUMULATION. THE BEST OPPORTUNITY FOR
ACCUMULATING SNOW WILL BE FROM EARLY FRIDAY EVENING THROUGH EARLY
SATURDAY MORNING WITH THE BEST JUXTAPOSITION OF FORCING...
MOISTURE...AND LAKE ENHANCEMENT. THIS PERIOD MAY SEE 2-3 INCHES OF
ACCUMULATION IN PERSISTENT BANDS FROM ROCHESTER WEST ACROSS THE
NIAGARA FRONTIER AND INTO THE NORTHERN PORTIONS OF THE WESTERN
SOUTHERN TIER. THERE MAY ALSO BE AN INCH OR TWO OF ACCUMULATION
ACROSS THE HIGHER TERRAIN EAST OF LAKE ONTARIO WITHIN THE NORTHERLY
UPSLOPE FLOW REGIME. THE LOWEST ACCUMULATIONS WILL LIKELY BE FOUND
AT THE SOUTHEAST CORNER OF LAKE ONTARIO FROM OSWEGO TO EASTERN WAYNE
COUNTIES...DUE TO LESS SYNOPTIC FORCING AND MOISTURE IN THAT AREA
AND THE FACT THAT THE EAST END OF LAKE ONTARIO IS ICE COVERED.

HIGHS ON FRIDAY WILL BE IN THE LOWER TO MID 30S ACROSS LOWER
ELEVATIONS AND AROUND 30 ON THE HILLS. THESE HIGHS ARE LIKELY TO
OCCUR DURING THE LATE MORNING AND MIDDAY...WITH ONGOING COLD
ADVECTION FORCING TEMPS TO FALL INTO THE 20S BY LATE IN THE DAY.
TEMPS WILL CONTINUE TO FALL FRIDAY NIGHT WITH STRONGER COLD
ADVECTION. EXPECT LOWS BY EARLY SATURDAY MORNING IN THE MID TEENS IN
MOST AREAS...WITH SINGLE NUMBERS ACROSS THE HIGH TERRAIN EAST OF
LAKE ONTARIO.

ON SATURDAY THE WRAP AROUND AND LAKE ENHANCED SNOW SHOWERS ACROSS
WESTERN NY WILL STILL BE GOING EARLY WITH SOME MINOR ADDITIONAL
ACCUMULATIONS. THE SNOW WILL GRADUALLY TAPER OFF DURING THE DAY AS
DEEPER MOISTURE AND ASCENT PULL AWAY AND ARE REPLACED BY INCREASING
SUBSIDENCE AND DRYING. TEMPERATURES WILL BE WAY OFF NORMAL ON
SATURDAY WITH HIGHS ONLY IN THE MID 20S ACROSS LOWER ELEVATIONS AND
BARELY 20 ON THE HILLS...A SOLID 20F BELOW NORMAL.

SATURDAY NIGHT A SURFACE RIDGE WILL BRIEFLY CREST ACROSS THE LOWER
LAKES WITH CLEARING SKIES. THE CLEARING WILL BRING ANOTHER COLD
NIGHT WITH LOWS WELL INTO THE TEENS IN MOST AREAS WITH SINGLE
NUMBERS ACROSS THE COOLER SOUTHERN TIER VALLEYS AND EAST OF LAKE
ONTARIO.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUNDAY HIGH PRESSURE WILL QUICKLY MOVE OFF THE EAST COAST AND ALLOW
WARM ADVECTION TO OVERSPREAD THE OHIO VALLEY AND LOWER LAKES AHEAD
OF THE NEXT SYSTEM. THIS WILL BRING SOME INCREASE IN MID/HIGH CLOUDS
FROM WEST TO EAST...BUT ANY PRECIP WILL HOLD OFF UNTIL SUNDAY NIGHT.
TEMPERATURES WILL BEGIN TO MODERATE SOMEWHAT...BUT STILL REMAIN
BELOW NORMAL WITH HIGHS IN THE UPPER 30S TO AROUND 40 AT LOWER
ELEVATIONS.

SUNDAY NIGHT THROUGH MONDAY A MODERATELY STRONG SURFACE LOW AND
ASSOCIATED MID LEVEL TROUGH WILL SWING ACROSS ONTARIO AND QUEBEC.
WARM ADVECTION AHEAD OF THE SYSTEM WILL BRING A CHANCE OF SOME LIGHT
SNOW SUNDAY NIGHT. BY MONDAY THE BOUNDARY LAYER MAY BECOME MILD
ENOUGH TO ALLOW FOR A RAIN/SNOW MIX BEFORE CHANGING BACK TO SNOW
MONDAY NIGHT. THE BETTER DYNAMICS AND MOISTURE FOR SNOW PRODUCTION
WILL REMAIN WELL NORTH OF THE AREA GIVEN THE SURFACE LOW TRACK TO
OUR NORTH...SO ANY ACCUMULATIONS SHOULD BE RELATIVELY MINOR.

MEDIUM RANGE GUIDANCE BEGINS TO DIVERGE BY TUESDAY AND WEDNESDAY OF
NEXT WEEK. A SERIES OF WEAK MID LEVEL SHORTWAVES AND SURFACE
FEATURES WILL CROSS THE GREAT LAKES AND OHIO VALLEY AS THE UPPER
LEVEL PATTERN ATTEMPTS TO DE-AMPLIFY AND BECOME MORE ZONAL. GIVEN
THE MODEL UNCERTAINTY...FOR NOW WILL STICK WITH CONTINUITY AND A
MAINLY DRY TUESDAY AND A LOW CHANCE OF RAIN SHOWERS WEDNESDAY AS
STRONGER WARM ADVECTION ARRIVES. TEMPERATURES WILL CREEP SLOWLY
UPWARD THROUGH THE FIRST HALF OF NEXT WEEK...WITH GOOD SIGNS IN BOTH
THE GFS AND ECMWF OF A STRONGER PUSH OF WARM AIR BY AROUND THURSDAY
OF NEXT WEEK.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
THERE IS A LOT OF MOISTURE IN THE LOWEST 2KFT DUE TO MOIST AIR
MOVING ACROSS THE COLD OR FROZEN LAKES. THIS MAY RESULT IN IFR CIGS
AND FOG NORTHEAST OF THE LAKES BUT THIS WILL BE DIFFICULT TO TIME.

A WAVE OF LOW PRESSURE WILL TRACK TO THE SOUTH OF THE AREA TODAY AND
BRING ABOUT 6 HOURS OF STEADY PRECIPITATION. TEMPERATURES ALOFT WILL
LIKELY BE COLD ENOUGH FOR RAIN TO MIX WITH SNOW THIS MORNING AND
TRANSITION TO ALL SNOW THIS AFTERNOON. THIS SHOULD LOWER CIGS TO IFR
OR LOWER. CONDITIONS WILL IMPROVE FROM W-E LATE IN THE DAY AS THE
SYSTEM EXITS.

OUTLOOK...
TONIGHT THROUGH FRIDAY NIGHT...MVFR WITH A CHANCE OF SNOW SHOWERS.
SATURDAY AND SUNDAY...VFR.
MONDAY...MVFR IN RAIN/SNOW SHOWERS.

&&

.MARINE...
A WAVE OF LOW PRESSURE WILL BRING A PERIOD OF RAIN AND SNOW ACROSS
THE LAKES TODAY. A COLD FRONT WILL THEN CROSS THE LOWER GREAT LAKES
ON FRIDAY...THIS WILL BRING INCREASING NORTHERLY WINDS BY LATE
FRIDAY THROUGH FRIDAY NIGHT. WILL NEED TO WATCH THIS TIME PERIOD FOR
POTENTIAL MARGINAL SMALL CRAFT ADVISORIES ALONG THE SOUTHERN SHORE
OF LAKE ONTARIO.

&&

.HYDROLOGY...
THE FORECAST SCENARIO HAS CHANGED QUITE A BIT OVER THE PAST FEW DAYS
WITH MODELS TRENDING STEADILY COLDER FOR THE SYSTEM TODAY...SO COLD
IN FACT THAT MUCH OF THE PRECIP WILL FALL AS WET SNOW ACROSS THE
BULK OF THE CWA. THE ONLY PLACES THAT MAY STAY RAIN FOR A LONGER
PERIOD OF TIME ARE ACROSS THE FAR UPPER REACHES OF THE GENESEE BASIN
AND THE FINGER LAKES. WITH MOST OF THE PRECIP FALLING AS WET SNOW
MUCH OF THE PRECIP WILL BE LOCKED UP IN A SLUSHY SNOW
ACCUMULATION...AND MELTING FROM THE REMAINING SNOWPACK WILL SLOW.

RUNOFF FROM THE WARMER TEMPS AND LIGHT RAIN YESTERDAY WILL RESULT IN
SOME RESPONSE TO THE CREEKS AND RIVERS IN WESTERN NY...ESPECIALLY
THE BUFFALO AREA CREEKS. THIS WILL CAUSE SOME DECENT WITHIN BANK
RISES...BUT WITHOUT THE ADDITIONAL RAINFALL TODAY THE POTENTIAL FOR
ANY MINOR FLOODING IS ALL BUT GONE. THE ONLY REMAINING CONCERN IS
THE POTENTIAL FOR ANY ICE JAMS...BUT MUCH OF THE ICE HAS BEEN
FLUSHED FROM THE CREEKS IN WESTERN NY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

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





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