Area Forecast Discussion
Issued by NWS Buffalo, NY

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000 FXUS61 KBUF 310845 AFDBUF AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 445 AM EDT TUE MAR 31 2015 .SYNOPSIS... A FAST MOVING CLIPPER LOW WILL BRING A PERIOD OF SNOW ACROSS THE SOUTHERN TIER TODAY...BEFORE HIGH PRESSURE AND DRY WEATHER RETURNS TONIGHT THROUGH WEDNESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL WEDNESDAY...BUT THURSDAY COULD BRING TEMPERATURES WELL ABOVE NORMAL. A COLD FRONT THURSDAY NIGHT SHOULD BRING RAIN AND GUSTY WINDS ACROSS THE AREA. THE POTENTIAL FOR UNSETTLED WEATHER REMAINS THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... WV IMAGERY SHOWS A DISTINCTIVE SHORTWAVE IN THE NORTHWESTERLY FLOW OVER MICHIGAN THIS MORNING. THIS WAVE WILL CONTINUE TO SLIDE QUICKLY SOUTHEASTWARD ACROSS PA BY THIS AFTERNOON AND OFF THE ATLANTIC COAST BY THIS EVENING. THIS TRAJECTORY WILL SEND PRECIPITATION OVERSPREADING THE SOUTHERN TIER TODAY...AND WITH A COOL AIRMASS IN PLACE ACROSS THE AREA ON THE NORTH SIDE OF THE WEAK SURFACE LOW TRACKING ACROSS PA...THIS SHOULD BE AN ALL SNOW EVENT. FARTHER NORTH ACROSS THE SOUTHERN SHORE OF LAKE ONTARIO FROM BUFFALO TO ROCHESTER AND INTO THE NORTH COUNTRY...THERE WILL BE LITTLE SENSIBLE IMPACT TO WEATHER TODAY...OTHER THAN A MAINLY CLOUDY AND COOL DAY AS THE NORTHERN SHIELD OF MID-HIGH LEVEL CLOUD COVER SLIDES ACROSS THE STATE. THE 00Z MODEL RUNS TRENDED THE TRACK OF THE WAVE SLIGHTLY BACK TO THE NORTH AGAIN. COMPARING THE 00Z MODEL SUITE FORECAST TO THIS MORNINGS RADAR/SATELLITE/SURFACE OBS...IT APPEARS THE PRECIPITATION SHIELD IS ACTUALLY EVEN SLIGHTLY FARTHER NORTH THAN THE MODELS FORECAST AS OF 08Z. FORECAST QPF IS FROM A CONSENSUS OF THE 00Z EC/GFS/GEM/NAM/(21Z)SREF WHICH WERE IN FAIRLY GOOD AGREEMENT...THEN ADJUSTED NORTHWARD SLIGHTLY BY BLENDING IN SOME 05Z HRRR...WHICH SEEMS TO BE BETTER CAPTURING THE CURRENT POSITION OF THE WAVE AND ASSOCIATED PRECIP SHIELD. THE BEST FORCING AND MOISTURE ASSOCIATED WITH THE WAVE WILL PASS JUST SOUTH OF THE FORECAST AREA...ACROSS NORTHERN PA...THIS WILL RESULT IN THE HIGHEST QPF AMOUNTS IN WESTERN NY OF AROUND A THIRD OF AN INCH CLOSEST TO JAMESTOWN AND THE SOUTHWEST CORNER OF THE STATE. ACROSS THE SOUTHERN TIER...SURFACE TEMPERATURES IN THE UPPER 20S WITH DEW POINTS IN THE LOW TO MID 20S ARE PRIMED TO SUPPORT ALL SNOW AT THE ONSET WITH THE WARM LAYER ALOFT SUPPRESSED WELL TO THE SOUTH ACROSS PA. THE GREATEST SNOWFALL AMOUNTS ARE EXPECTED AROUND THE JAMESTOWN AREA INTO THE SOUTHWEST CORNER OF CHAUTAUQUA COUNTY. THE COMBINATION OF THE HIGHEST QPF AMOUNTS AND EARLY DAY TIMING WILL SUPPORT SNOW ACCUMULATIONS OF 2 TO 3 INCHES...AND WOULD NOT RULE OUT AN ISOLATED 4 INCH REPORT IN THE FAR SOUTHWEST CORNER...BUT FORECAST CONFIDENCE IN THAT HAPPENING IS VERY LOW AND NOT ENOUGH TO WARRANT AN ADVISORY. THE REST OF THE SOUTHERN TIER / INCLUDING CATTARAUGUS AND ALLEGANY COUNTIES / SHOULD SEE 1 TO 3 INCHES OF SNOW ACCUMULATION WITH THE HIGHEST AMOUNTS CLOSEST TO THE PA BORDER. THESE LOCATIONS WILL ALSO INCREASING HAVE TO CONTEND WITH DAYTIME HEATING AND SOLAR INSOLATION THROUGH THE CLOUD COVER WORKING AGAINST SNOW ACCUMULATIONS...ESPECIALLY ON PAVED SURFACES. THUS ACCUMULATING SNOW WILL BECOME MORE LIMITED TO GRASSY AND ELEVATED SURFACES. AS SNOW RATES DECREASE INTO THE AFTERNOON...AND EVENTUALLY THE SNOW ENDS FROM WEST TO EAST ACROSS THE SOUTHERN TIER...TEMPERATURES SHOULD MANAGE TO CLIMB A COUPLE TO A FEW DEGREES ABOVE FREEZING. ANY ACCUMULATED SNOW REMAINING ON PAVED SURFACES AT THAT POINT SHOULD QUICKLY MELT OFF BY MID TO LATE AFTERNOON. ELSEWHERE / INCLUDING BUFFALO...ROCHESTER AND THE NORTH COUNTRY / LOCATIONS ALONG AND SOUTH OF THE THRUWAY COULD SEE SOME LIGHT SNOW SHOWERS FROM LATE MORNING THROUGH EARLY AFTERNOON...BUT SHOULD BE OF LITTLE CONSEQUENCE. LOCATIONS NORTH OF THE THRUWAY SHOULD SEE AN ENTIRELY DRY DAY. WITHOUT ANY PRECIPITATION TO CONTENT WITH...TEMPERATURES WILL CLIMB INTO THE UPPER 30S THIS AFTERNOON...WITH THE CLOUD COVER LIKELY KEEPING MOST LOCATIONS FROM TOUCHING 40. TONIGHT...THE SHORTWAVE AND SNOW ACROSS THE SOUTHERN TIER WILL BE LONG GONE AND DRY AIR WILL WORK IN FROM THE NORTH ACROSS THE FORECAST AREA. THIS WILL ALLOW FOR CLOUD COVER TO CLEAR OUT QUICKLY FROM NORTH TO SOUTH ACROSS THE AREA. WITH THE NORTH COUNTRY CLEARING OUT EARLY AND LIGHT WINDS IN PLACE...RADIATIONAL COOLING SHOULD ALLOW TEMPERATURES TO DROP INTO LOW TO MID TEENS OVERNIGHT. ELSEWHERE...SOME THIN LINGERING CLOUD COVER SHOULD HELP KEEP TEMPERATURES IN THE LOW 20S. A WEAK SHORTWAVE IN THE NORTHWESTERLY FLOW MAY BRING A FEW LIGHT SNOW SHOWERS BACK INTO THE WESTERN SOUTHERN TIER LATE TONIGHT...BUT THESE SHOULD NOT LAST LONG AND WILL RESULT IN LITTLE ADDITIONAL SNOW ACCUMULATIONS. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... WEDNESDAY MORNING ANOTHER MUCH WEAKER CLIPPER WILL MOVE ACROSS LAKE ERIE AND THE UPPER OHIO VALLEY. ANY LIGHT PRECIP WITH THIS SHOULD REMAIN WEST OF OUR REGION...BUT IT WILL BRING SOME CLOUD COVER TO THE AREA DURING THE MORNING ESPECIALLY FROM THE GENESEE VALLEY AND WESTERN FINGER LAKES INTO WESTERN NY. THE MORNING CLOUDS SHOULD QUICKLY DIMINISH FOR THE AFTERNOON AS THE CLIPPER WASHES OUT AND HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION WITH INCREASING DRYING AND SUBSIDENCE. DESPITE THE INCREASING SUNSHINE TEMPERATURES WILL REMAIN BELOW NORMAL...WITH UPPER 30S TO AROUND 40 ACROSS THE LOWER ELEVATIONS OF WESTERN NY AND LOW TO MID 30S ACROSS THE NORTH COUNTRY. HIGH PRESSURE SETTLES OVERHEAD WEDNESDAY EVENING BEFORE DRIFTING TO THE EASTERN SEABOARD OVERNIGHT. THIS WILL BRING MAINLY CLEAR SKIES AND LIGHT WINDS INITIALLY...WHICH WILL ALLOW FOR SOME EARLY RADIATIONAL COOLING. OVERNIGHT SOUTHERLY RETURN FLOW WILL DEVELOP IN THE WAKE OF THE DEPARTING HIGH AND FORCE RISING TEMPERATURES. A WARM FRONTAL SEGMENT WILL MOVE QUICKLY FROM SOUTHWEST TO NORTHEAST ACROSS THE AREA LATE WEDNESDAY NIGHT...REACHING THE NORTH COUNTRY BY EARLY THURSDAY MORNING. THE DEEPEST MOISTURE AND STRONGEST ISENTROPIC UPGLIDE WITH THE WARM FRONT WILL CROSS LAKE ONTARIO AND THE EASTERN LAKE ONTARIO REGION...WHERE A FEW RAIN AND SNOW SHOWERS ARE POSSIBLE LATE WEDNESDAY NIGHT AND EARLY THURSDAY. FOR THE REST OF THE AREA...DRY LOW LEVELS SHOULD KEEP ANY PRECIP FROM REACHING THE GROUND WITH JUST A PERIOD OF MID LEVEL CLOUD COVER. THE WARM FRONT WILL EXIT THE NORTH COUNTRY EARLY THURSDAY...LEAVING THE ENTIRE CWA IN THE WARM SECTOR FOR THE DAY. DEEP SSW FLOW WITHIN THE WARM SECTOR WILL ALLOW 850MB TEMPS TO SOAR TO NEAR +10C. THE COMBINATION OF A MUCH WARMER AIRMASS AND SSW DOWNSLOPE FLOW WILL BOOST TEMPERATURES INTO THE MID 60S ON THE LAKE PLAINS OF WESTERN NY...WITH MID TO UPPER 50S ACROSS THE INTERIOR SOUTHERN TIER AND EASTERN LAKE ONTARIO REGION. THE LAST TIME WE SAW A HIGH TEMP OF 60F OR HIGHER WAS NOVEMBER 30TH AT BUFFALO AND ROCHESTER. THE SSW WIND DIRECTION WILL KEEP MOST OF THE LAKE COOLING ON THE CANADIAN SIDE OF THE BORDER...EXCEPT FOR AREAS ALONG THE NIAGARA RIVER OFF LAKE ERIE AND NEAR CAPE VINCENT OFF LAKE ONTARIO WHERE HIGHS WILL BE CONSIDERABLY COOLER. MOST OF THURSDAY WILL BE RAIN FREE...BUT ONGOING WARM ADVECTION AND ISENTROPIC UPGLIDE COMBINED WITH THE APPROACH OF THE INITIAL MID LEVEL HEIGHT FALLS AND DPVA COULD PRODUCE A FEW WIDELY SCATTERED SHOWERS DURING THE AFTERNOON WITH A MIX OF SUN AND CLOUDS. A FAIRLY STRONG COLD FRONT WILL CROSS THE AREA THURSDAY NIGHT ALONG WITH A CONVECTIVELY AUGMENTED MID LEVEL SHORTWAVE AND LOW LEVEL JET MAX. THIS WILL PRODUCE SEVERAL HOURS OF SHOWERS...REACHING WESTERN NY DURING THE MID EVENING THEN SPREADING EAST TO THE EASTERN LAKE ONTARIO REGION BY AROUND MIDNIGHT. FORCING WILL BE FAIRLY STRONG... WITH CONVERGENCE ENHANCED BY A 60+ KNOT LOW LEVEL JET. A PLUME OF DEEPER MOISTURE WILL BE CAPTURED BY THIS SYSTEM...WITH PWAT RISING TO AROUND 1.25 INCHES ALONG THE FRONT. THE COMBINATION OF QUALITY MOISTURE AND DYNAMICS WILL PRODUCE RAINFALL AMOUNTS OF A QUARTER TO THIRD OF AN INCH OVER A FEW HOURS. BOTH THE NAM AND GFS ALSO SHOW SOME LINGERING MARGINAL INSTABILITY ALONG THE ADVANCING FRONT WITH AROUND 100J/KG OF ELEVATED CAPE AND SHOWALTER INDEX NEAR 0C. WHILE THESE INSTABILITY VALUES ARE EXTREMELY MARGINAL...IN THE PRESENCE OF A STRONGLY FORCED ENVIRONMENT IT MAY BE ENOUGH FOR A FEW ISOLATED TO SCATTERED THUNDERSTORMS ALONG THE FRONT. GIVEN THE STRENGTH OF THE LOW LEVEL WIND FIELD...ANY CONVECTIVE SHOWERS /WITH OR WITHOUT THUNDER/ ALONG THE FRONT MAY PRODUCE VERY GUSTY WINDS. THE RAIN WILL QUICKLY END FROM WEST TO EAST OVERNIGHT AS THE COLD FRONT MOVES EAST OF THE AREA AND A STRONG PUSH OF DRYING MOVES INTO THE LOWER LAKES. && .LONG TERM /FRIDAY THROUGH MONDAY/... FRIDAY WILL START OFF DRY...BUT LATER FRIDAY AND FRIDAY NIGHT MOST MEDIUM RANGE GUIDANCE CONTINUES TO SUGGEST A SECONDARY FRONTAL WAVE WILL MOVE THROUGH THE OHIO VALLEY AND INTO THE NORTHEAST FORCED BY A STRONG MID LEVEL SHORTWAVE MOVING ALONG THE ADVANCING BAROCLINIC ZONE. THIS WILL BRING INCREASING CHANCES OF PRECIP AGAIN LATER FRIDAY AFTERNOON AND ESPECIALLY FRIDAY NIGHT. THE ECMWF REMAINS STRONGER AND FARTHER NORTH WITH THIS FEATURE THAN THE GFS...AND HAS SUPPORT FROM THE 00Z CANADIAN GEM WITH A SIMILAR TRACK AND INTENSITY. AS THIS SYSTEM PASSES BY TO OUR SOUTH...COLDER AIR WILL BE FILTERING INTO THE REGION AND ALLOW RAIN TO CHANGE TO SNOW FRIDAY NIGHT. IF THE TIMING AND TRACK ARE JUST RIGHT THERE COULD EVEN BE SOME ACCUMULATION. THIS SYSTEM WILL QUICKLY MOVE AWAY FROM THE AREA SATURDAY MORNING WITH JUST A FEW LEFTOVER SNOW SHOWERS IN COLD NORTHWEST FLOW DURING THE FIRST HALF OF THE DAY. TEMPERATURES WILL AGAIN DROP TO WELL BELOW NORMAL WITH HIGHS ONLY IN THE 30S. ANOTHER COLD FRONT WILL CROSS THE AREA SATURDAY NIGHT WITH A CHANCE OF MORE SNOW SHOWERS. THIS WILL KEEP COLD AIR IN PLACE FOR EASTER SUNDAY WITH HIGHS AGAIN ONLY IN THE 30S. HIGH PRESSURE AND DRYING ALOFT SHOULD KEEP SUNDAY DRY WITH A DECENT AMOUNT OF SUNSHINE. BY MONDAY BOTH THE GFS AND ECWMF BRING A SHARP BAROCLINIC ZONE SLOWLY NORTHWARD ACROSS THE AREA...WITH A CHANCE OF SOME RAIN AND WET SNOW. LOOKING A LITTLE FARTHER AHEAD...BEHIND THIS SLOWLY MOVING BOUNDARY ANOTHER PUSH OF MUCH WARMER AIR SHOULD ARRIVE FOR AT LEAST A DAY OR TWO AROUND THE MIDDLE OF NEXT WEEK. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... A CLIPPER LOW WILL BRING WIDESPREAD SNOW ACROSS THE NY SOUTHERN TIER / PA NORTHERN TIER TODAY. CONDITIONS AT KJHW WILL QUICKLY DETERIORATE TO IFR OR LOWER THIS MORNING AS SNOW COULD BE HEAVY AT TIMES THROUGH LATE MORNING. SNOW WILL TAPER OFF FROM WEST TO EAST ACROSS THE SOUTHERN TIER THIS AFTERNOON. INITIALLY IFR CIGS WILL LINGER AT JHW WITH UPSLOPE FLOW IN PLACE...BUT DRIER AIR WILL EVENTUALLY WORK IN FROM THE NORTH TONIGHT TO BREAK UP THE LOW CLOUD DECK. ELSEWHERE...KIAG/KBUF/KROC/KART WILL SEE LITTLE TO NO IMPACT FROM THE CLIPPER LOW OUTSIDE OF MID-HIGH LEVEL CLOUDS ACROSS THE AREA TODAY...AND THUS VFR CONDITIONS WILL PREVAIL. WOULD NOT RULE OUT SOME ISOLATED/SCATTERED SNOW SHOWERS NEAR KBUF FROM MID MORNING TO EARLY AFTERNOON...BUT THESE SHOULD REMAIN SOUTH OF THE TERMINAL. OUTLOOK... WEDNESDAY...VFR. THURSDAY AND THURSDAY NIGHT...VFR/MVFR WITH RAIN SHOWERS BECOMING LIKELY LATER IN THE DAY. FRIDAY...VFR/MVFR WITH A CHANCE OF RAIN SHOWERS. SATURDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS. && .MARINE... EXPECT A PERIOD OF LIGHT TO MODEST NORTHEASTERLIES AND NORTHERLIES TODAY AND TONIGHT AS A CLIPPER SYSTEM PASSES ACROSS THE OHIO VALLEY... BEFORE HIGH PRESSURE AND LIGHT WINDS BUILD BACK ACROSS THE GREAT LAKES ON WEDNESDAY. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...CHURCH NEAR TERM...CHURCH SHORT TERM...HITCHCOCK LONG TERM...HITCHCOCK AVIATION...CHURCH MARINE...CHURCH

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