Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 051442
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1042 AM EDT TUE MAY 5 2015

.SYNOPSIS...
WITH A FRONT STALLED JUST SOUTH OF NEW YORK TODAY...TEMPERATURES
WILL RUN ABOUT 10 DEGREES COOLER THAN YESTERDAY...BUT THAT STILL
MEANS HIGHS NEAR 70 FOR MOST LOCATIONS. A WAVE OF LOW PRESSURE WILL
THEN TRACK ALONG THE STALLED FRONT TONIGHT AND BRING RAIN TO AREAS
SOUTH OF THE THRUWAY...WHILE THE NORTH COUNTRY REMAINS CLEAR AND
DRY. FOLLOWING THE PASSAGE OF THIS WAVE...THE REMAINDER OF THE WORK
WEEK WILL FEATURE A RETURN TO DRY WEATHER AND ABOVE NORMAL
TEMPERATURES...BEFORE THE NEXT CHANCE FOR PRECIPITATION ARRIVES THIS
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1440Z...THE AREAS OF FOG THAT IMPACTED PORTIONS OF THE AREA
EARLIER THIS MORNING HAVE SINCE DISSIPATED...LEAVING BEHIND PARTLY
TO MOSTLY SUNNY SKIES AS OF THIS WRITING.

THE ABOVE STATED...A WEAK SURFACE FRONTAL BOUNDARY REMAINS STALLED
OUT ACROSS THE NORTHERN OHIO VALLEY AND NORTHERN PA...AND AS A WAVE
OF LOW PRESSURE OVER THE CENTRAL MISSISSIPPI VALLEY RIDES EASTWARD
ALONG THIS BOUNDARY THROUGH THE REMAINDER OF THE DAY...IT WILL BRING
INCREASING CLOUDS TO MOST LOCATIONS SOUTH OF LAKE ONTARIO THIS
AFTERNOON...ALONG WITH THE EVENTUAL CHANCE OF A FEW SHOWERS TO AREAS
ALONG AND SOUTH OF A KBUF-KDSV LINE. MEANWHILE FURTHER TO THE
NORTH...EXPECT DRY WEATHER AND GENERAL PARTLY TO MOSTLY SUNNY SKIES
TO CONTINUE THROUGH THE DAY. TEMPERATURE-WISE...850 MB TEMPS
AVERAGING WITHIN A COUPLE DEGREES EITHER SIDE OF +8C WILL ALLOW FOR
HIGHS RANGING FROM THE UPPER 60S TO LOWER 70S IN MOST LOCATIONS.

THE INTERESTING PART OF THE FORECAST COMES FOR THIS EVENING AND
OVERNIGHT. THE REMNANT WAVE FROM AN ONGOING MCS OVER THE MIDWEST
WILL TRACK ALONG THE STALLED FRONTAL BOUNDARY AND WILL START TO DRAW
THE BOUNDARY NORTHWARD AS IT APPROACHES. THE 00Z MODEL SUITE
UNANIMOUSLY TRENDED NORTHWARD WITH THE TRACK OF THIS WAVE AND THE
PLACEMENT OF THE BAROCLINIC ZONE FOR TONIGHT. WITH CONFIDENCE
INCREASING NOW THAT RADAR/SATELLITE OBSERVATIONS SHOW THE PLACEMENT
OF THE MCS...HAVE INCREASED THE POPS TO CATEGORICAL ACROSS THE
WESTERN SOUTHERN TIER AND AREAS JUST SOUTH OF THE THRUWAY.
CONFIDENCE IS HIGHEST IN THIS AREA RECEIVING PRECIPITATION REGARDLESS
OF SMALL CHANGES IN THE TRACK OF THE WAVE...AND ALL STAND TO SEE THE
HIGHEST QPF AMOUNTS...UP TO AN INCH OVERNIGHT. CONFIDENCE IS LOWER
ON HOW MUCH PRECIPITATION AREAS FROM BUFFALO TO ROCHESTER WILL
RECEIVE AS THERE WILL BE A SHARP NORTHERN CUT OFF TO THE
PRECIPITATION SHIELD WITH DRIER NORTHERLY FLOW IN PLACE ACROSS THE
NORTH COUNTRY AND LAKE ONTARIO. GIVEN THE NORTHWARD TREND IN THE
MODEL GUIDANCE...HAVE INCREASED POPS NORTHWARD INTO THE BUFFALO AREA
AND ALONG THE THRUWAY...WITH CHANCES TAPERING OFF QUICKLY NORTH OF
THE THRUWAY.

TEMPERATURES OVERNIGHT TONIGHT WILL ACTUALLY BE FAIRLY MILD AS THE
BAROCLINIC ZONE IS ALMOST OVERHEAD. THE SOUTHERN TIER NORTH TO THE
NIAGARA FRONTIER AND INTO THE FINGER LAKES REGION WILL BE THE
WARMEST GIVEN THE CLOUD COVER AND WARMER AIR TRYING TO PUSH
NORTHWARD. LOWS THERE WILL BE IN THE UPPER 40S TO NEAR 50. THE NORTH
COUNTRY WILL FEEL LITTLE TO IMPACT FROM THE WAVE...AND WILL ACTUALLY
REMAIN MOSTLY CLEAR OVERNIGHT. THE LACK OF CLOUD COVER...LIGHT WINDS
AND BEING ON THE COOL SIDE OF THE FRONT WILL ALLOW TEMPERATURES TO
DROP TO AROUND 40.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A CONVECTIVELY GENERATED FRONTAL WAVE WILL BE EXITING INTO EASTERN
PA AND SOUTHEAST NY WEDNESDAY MORNING...TAKING THE BULK OF RAIN
CHANCES WITH IT. WEAK CONVERGENCE WILL BE LEFT ACROSS THE SOUTHERN
TIER IN THE WAKE OF THE FRONTAL WAVE...AND THIS MAY STILL SUPPORT A
FEW SCATTERED LIGHT SHOWERS THROUGH MIDDAY. OTHERWISE FOR THE REST
OF THE AREA SURFACE HIGH PRESSURE BUILDING OUT OF THE UPPER GREAT
LAKES AND TOWARDS NORTHERN NY WILL PROVIDE A DRY DAY FROM THE NYS
THRUWAY NORTHWARD. MID LEVEL CLOUDS TO THE NORTH OF THE FRONTAL WAVE
DURING THE MORNING SHOULD THIN BY AFTERNOON AND LEAVE INCREASING
SUNSHINE FOR THE BULK OF THE AREA...WITH CLOUDS LINGERING MUCH OF
THE DAY ACROSS THE WESTERN SOUTHERN TIER NEAR THE OLD FRONTAL
BOUNDARY. THE NORTH COUNTRY WILL SEE THE MOST SUNSHINE BENEATH MORE
DRYING AND SUBSIDENCE NEAR THE CENTER OF THE HIGH.

NOT MUCH COOL AIR BEHIND THE FRONTAL ZONE AT ALL...WITH HIGHS IN THE
MID 70S AWAY FROM THE LAKESHORES. LIGHT NORTH TO NORTHEAST WINDS
WILL KEEP THE SOUTH SHORE OF LAKE ONTARIO AND THE LAKE ERIE SHORE
SOUTHWEST OF HAMBURG MUCH COOLER...WITH A LAKE BREEZE DEVELOPING AT
THE NORTHEAST END OF LAKE ONTARIO AS WELL.

THE FRONTAL ZONE WILL SINK FARTHER SOUTH WEDNESDAY NIGHT AND WASH
OUT...WITH HIGH PRESSURE BUILDING OVER THE LOWER LAKES AND NEW
ENGLAND. SKIES WILL CLEAR AS SUBSIDENCE AND DRYING TAKE HOLD BEHIND
THE WEAKENING FRONTAL ZONE.

HIGH PRESSURE DRIFTS OFF THE EASTERN SEABOARD THURSDAY AND ALLOWS
DEEP SOUTHWEST RETURN FLOW TO SET UP ACROSS THE OHIO VALLEY AND
LOWER LAKES. THIS WILL BE THE START OF A TREND TOWARDS MID SUMMER
HEAT BY THE END OF THE WEEK. 850MB TEMPS REACH +11C OR SO
THURSDAY...SUPPORTING HIGHS IN THE UPPER 70S INLAND FROM THE LAKES.
THE NORMALLY WARMER MID GENESEE VALLEY WILL REACH NEAR 80. THE
SYNOPTIC SCALE FLOW IS LIGHT...WITH STRONG DIFFERENTIAL HEATING
ALLOWING LAKE BREEZES TO FORM BY AFTERNOON WITH ONSHORE WIND AND
COOLER TEMPERATURES ALONG ALL THE LAKESHORES.

BOTH THE NAM AND GFS TRY TO DEVELOP SOME SCATTERED CONVECTION FROM
THE WESTERN SOUTHERN TIER INTO THE FINGER LAKES DURING THE
AFTERNOON...BUT THIS DOES NOT SEEM PLAUSIBLE GIVEN HIGH PRESSURE
SURFACE AND ALOFT...DEVELOPING MID LEVEL CAPPING...AND VERY LIMITED
INSTABILITY. WITH THIS IN MIND...HAVE GONE WITH A DRY FORECAST FOR
THE ENTIRE CWA THURSDAY.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
MID SUMMER HEAT WILL BE THE BIG STORY THROUGH MUCH OF THE LONG TERM
AS AN EXPANSIVE RIDGE STRETCHING FROM THE EASTERN UNITED STATES INTO
THE WESTERN ATLANTIC SETS UP A BERMUDA HIGH TYPE PATTERN. SEVERAL
DAYS OF DEEP SOUTHWEST FLOW ACROSS THE OHIO VALLEY WILL PUMP VERY
WARM AND INCREASINGLY HUMID AIR INTO OUR REGION FRIDAY THROUGH MUCH
OF THE WEEKEND.

LOOKING AT THE DETAILS...ON FRIDAY HIGH PRESSURE SURFACE AND ALOFT
WILL REMAIN ACROSS THE REGION. BOTH THE GFS AND ECMWF HAVE A WEAK
QPF SIGNAL SUGGESTING SOME CONVECTIVE POTENTIAL INLAND FROM THE
LAKES...BUT WITH VERY WARM MID LEVELS INSTABILITY WILL BE LIMITED
AND LIKELY CAPPED. WITH THIS IN MIND HAVE KEPT FRIDAY DRY. 850MB
TEMPS RISE TO NEAR +15C SUPPORTING HIGHS IN THE LOWER TO MID 80S AWAY
FROM THE LAKES.

OVER THE WEEKEND DEEPER MOISTURE WILL ARRIVE WITH SURFACE DEWPOINTS
NEARING 60F...SUPPORTING GREATER DIURNAL INSTABILITY. THE GFS LEANS
A WEAK FRONTAL ZONE INTO THE AREA LATE SATURDAY THROUGH SUNDAY...
WHILE THE ECMWF HOLDS THIS BOUNDARY FARTHER NORTHWEST ACROSS THE
CENTRAL GREAT LAKES. THE ECMWF SOLUTION SEEMS MORE REASONABLE GIVEN
THE STRENGTH OF THE EAST COAST RIDGE. WITH THIS IN MIND...ANY
SHOWERS AND STORMS THAT DO DEVELOP OVER THE WEEKEND WILL BE WIDELY
SCATTERED AND DIURNAL IN NATURE. WHILE THERE WILL BE A CHANCE OF
RAIN IN THE FORECAST BOTH DAYS...THE VAST MAJORITY OF THE TIME
SHOULD BE RAIN FREE IF THE FRONTAL ZONE STAYS TO OUR NORTHWEST.
TEMPERATURES WILL REMAIN VERY WARM SATURDAY WITH LOWER TO MID 80S...
MAYBE JUST A FEW DEGREES LOWER SUNDAY WITH MORE CLOUD COVER.

BY MONDAY THE ECMWF BRINGS THE FRONTAL ZONE A LITTLE CLOSER...WHICH
WOULD PRODUCE BETTER COVERAGE OF SCATTERED SHOWERS AND STORMS.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
AS OF 1440Z...ANY AREAS OF EARLY MORNING FOG HAVE DISSIPATED...
LEAVING BEHIND MAINLY VFR CONDITIONS THAT ARE EXPECTED TO CONTINUE
THROUGH THE AFTERNOON.

THIS EVENING...RAIN WILL SPREAD ACROSS AREAS ALONG AND SOUTH OF THE
NEW YORK STATE THRUWAY. KJHW WILL SEE THE MOST IMPACT...WITH CIGS
DETERIORATING TO AT LEAST MVFR IF NOT IFR TONIGHT. THERE WILL BE A
SHARP NORTHERN CUT-OFF TO THE PRECIPITATION AND CLOUD COVER...AND IT
REMAINS TO BE SEEN WHERE THAT LINE WILL BE DRAWN. CURRENT THINKING IS
THAT KBUF/KIAG WILL STRADDLE THAT NORTHERN EDGE...BUT BE JUST INTO
THE RAIN...WHILE KROC MAIN AVOID THE RAIN ENTIRELY. KART WILL SEE
CLEAR SKIES AND VFR CONDITIONS TONIGHT.

OUTLOOK...
WEDNESDAY THROUGH FRIDAY...VFR.
SATURDAY AND SUNDAY...MAINLY VFR WITH A CHANCE OF MVFR IN RAIN
SHOWERS.

&&

.MARINE...
TODAY AND WEDNESDAY...HIGH PRESSURE OVER THE LOWER GREAT
LAKES WILL ONLY PRODUCE LIGHT WINDS AND NEGLIGIBLE WAVES.

&&

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

&&

$$

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


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