Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 311151
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
751 AM EDT SUN AUG 31 2014

.SYNOPSIS...
A SLOW MOVING TROUGH OF LOW PRESSURE WILL PRODUCE OCCASIONAL SHOWERS
AND SCATTERED THUNDERSTORMS ACROSS MUCH OF THE REGION THIS MORNING
BEFORE SLOWLY TAPERING OFF FROM NORTHWEST TO SOUTHEAST THIS
AFTERNOON. IT WILL REMAIN MUGGY ALTHOUGH EXTENSIVE CLOUD COVER WILL
KEEP TEMPERATURES LOWER THAN YESTERDAY. A FEW SPOTTY SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ON LABOR DAY...BUT THE MAJORITY OF THE
DAY SHOULD BE RAIN FREE WITH TEMPERATURES WARMING BACK TO A LITTLE
ABOVE AVERAGE.

&&

.NEAR TERM /THROUGH TONIGHT/...
RADAR IMAGERY THIS MORNING SHOWING A SOLID AREA OF LIGHT RAIN
COVERING MUCH OF THE REGION...WITH A FEW POCKETS OF MODERATE RAIN
ACROSS THE SOUTHERN TIER AND CENTRAL NY. THE WIDESPREAD NATURE OF
THE RAIN IS LIKELY DUE TO MID LEVEL DEFORMATION AND FRONTOGENESIS
FROM A WEAK BAROCLINIC LEAF NOTED IN IR SATELLITE IMAGERY. THIS
STEADY RAIN WILL SHIFT SLOWLY EAST THROUGH THE REGION THROUGH
MIDDAY. THE BACK EDGE IS NEAR KERI-KBUF AT 1130Z...AND MUCH OF THE
NIAGARA FRONTIER WILL MISS OUT ON THE STEADIER RAIN. THAT SAID...
THE BACK EDGE MAY NOT STAY CLEAN WITH MESOSCALE MODEL GUIDANCE SUCH
AS THE HRRR SUGGESTING CONVECTIVE SHOWERS WILL DEVELOP BY LATE
MORNING ACROSS THE NIAGARA FRONTIER JUST WEST OF THE STEADIER RAIN.

FOR TODAY A MID LEVEL TROUGH WILL ADVANCE EAST ACROSS THE CENTRAL
GREAT LAKES...WITH DOWNSTREAM HEIGHT FALLS AND DPVA PRODUCED BY
CONVECTIVELY AUGMENTED VORTICITY MAXIMA AIDING IN LARGE SCALE
ASCENT. UPPER LEVEL DIVERGENCE WILL BE ENHANCED BY THE RIGHT
ENTRANCE REGION OF A 80+ KNOT UPPER LEVEL JET STRETCHING FROM LOWER
MICHIGAN TO SOUTHERN QUEBEC. A BELT OF 30-35 KNOT FLOW IN THE
900-700MB LAYER WILL AID IN ORGANIZING CONVERGENCE AND MOISTURE
TRANSPORT. AT THE SURFACE WEAK/ELONGATED LOW PRESSURE WILL MOVE INTO
SOUTHERN QUEBEC WITH A WEAK PRE-FRONTAL TROUGH EASING ACROSS THE
LOWER LAKES PROVIDING LOW LEVEL CONVERGENCE. IR SATELLITE IMAGERY
SHOWING A WEAK BAROCLINIC LEAF DEVELOPING ACROSS THE OHIO VALLEY
EARLY THIS MORNING. AS THIS FEATURE TRANSLATES NORTHEAST TODAY IT
WILL ACT TO ENHANCE MID LEVEL FRONTOGENESIS AND DEFORMATION ACROSS
OUR REGION...AIDING IN MORE WIDESPREAD SHOWERS. PWAT VALUES ARE
AROUND 1.8 INCHES ON AVERAGE WITH AMPLE MOISTURE IN PLACE.

GIVEN THE QUALITY MOISTURE AND SUFFICIENT FORCING FOR ASCENT COMING
TOGETHER...HAVE RAISED POPS TO CATEGORICAL FOR THE BULK OF THE AREA
THIS MORNING WITH THE EXCEPTION OF A FEW COUNTIES ALONG THE CANADIAN
BORDER WHERE SHOWERS SHOULD BE A LITTLE LESS FREQUENT. IN GENERAL
THE MOST PERSISTENT RAIN AND HIGHEST AMOUNTS SHOULD FOCUS FROM THE
WESTERN SOUTHERN TIER TO THE FINGER LAKES AND SOUTHERN TUG HILL
REGION WITH LESSER AMOUNTS NEAR THE INTERNATIONAL BORDER. ENOUGH
INSTABILITY WILL REMAIN TO KEEP A FEW EMBEDDED THUNDERSTORMS AS
WELL...ALTHOUGH COVERAGE WILL REMAIN WIDELY SCATTERED. A FEW STORMS
MAY PRODUCE LOCALLY HEAVY RAINFALL...BUT THIS RISK SHOULD REMAIN
VERY ISOLATED AT BEST.

THIS AFTERNOON THE AFOREMENTIONED DYNAMICS AND BAROCLINIC LEAF WILL
SHIFT SLOWLY SOUTH AND EAST AND TAKE THE STEADIER SHOWERS WITH IT.
EXPECT A DRYING TREND FOR THE AFTERNOON FROM NORTHWEST TO SOUTHEAST
WITH AREAS ALONG AND NORTH OF THE NYS THRUWAY EVENTUALLY BECOMING
MAINLY DRY WITH A FEW BREAKS OF SUNSHINE POSSIBLE LATE. SHOWERS WILL
BE SLOWER TO END ACROSS THE SOUTHERN TIER AND ACROSS THE HIGHER
TERRAIN EAST OF LAKE ONTARIO.

THE EXTENSIVE CLOUD COVER WILL KEEP TEMPERATURES LOWER TODAY
ALTHOUGH IT WILL STILL BE VERY MUGGY. EXPECT HIGHS IN THE UPPER 70S
ON THE LAKE PLAINS AND LOWER TO MID 70S ACROSS THE HIGHER TERRAIN.
THE WARM SPOT SHOULD BE THE SAINT LAWRENCE VALLEY WHERE SHOWERS AND
THICKER CLOUD COVER WILL EXIT THE EARLIEST.

TONIGHT SHOWERS ACROSS THE SOUTHERN TIER AND CENTRAL NY WILL
CONTINUE TO SLOWLY DIMINISH. ENOUGH INSTABILITY MAY DEVELOP IN THE
WAKE OF THIS MAIN RAIN AREA TO ALLOW SCATTERED THUNDERSTORMS TO FORM
DURING THE LATE AFTERNOON AND EARLY EVENING ACROSS THE NIAGARA
PENINSULA. IF THEY MATERIALIZE...A FEW MAY MAKE IT INTO AREAS JUST
NORTH OF BUFFALO THIS EVENING. SCATTERED STORMS MAY ALSO FORM OVER
SOUTHEAST ONTARIO AND CROSS THE SAINT LAWRENCE INTO THE NORTH
COUNTRY THIS EVENING. OTHERWISE EXPECT SOME PARTIAL CLEARING
OVERNIGHT ON THE LAKE PLAINS. ACROSS THE HIGHER TERRAIN LOW LEVEL
MOISTURE AND WEAK UPSLOPE FLOW AND CONVERGENCE WILL LIKELY SUPPORT
EXPANDING LOW CLOUD COVER. EXPECT LOWS IN THE MID TO UPPER 60S ON
THE LAKE PLAINS AND LOWER TO MID 60S IN THE SOUTHERN TIER AND NORTH
COUNTRY.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
A WARM AND STICKY AIRMASS WILL REMAIN ACROSS THE REGION ON
MONDAY...WITH MOST OF THE FORECAST AREA EXPERIENCING MAINLY DRY
CONDITIONS. HOWEVER THERE WILL BE THE CHANCE FOR SCATTERED SHOWERS
AND THUNDERSTORMS IN THE AFTERNOON AND EVENING...MAINLY ACROSS THE
INTERIOR SOUTHERN TIER WHERE THE BEST INSTABILITY WILL RESIDE. CAPE
VALUES BY LATER IN THE AFTERNOON ACROSS THIS REGION WILL RUN IN THE
1000-1500 J/KG RANGE WITH LI`S POSSIBLY AS LOW AS -4. HOWEVER WITH
WEAK 0-6KM BULK SHEAR (~20KTS) AND LACK OF A GOOD SURFACE TRIGGER
(ASIDE FROM A POSSIBLE LAKE BREEZE)...NOT EXPECTING ANY
THUNDERSTORMS TO REACH SEVERE LIMITS. INSTABILITY LOOKS LOWER ACROSS
THE REMAINDER OF THE AREA...AND THUS CONVECTIVE CHANCES LOOK MUCH
LOWER AS WELL. TEMPERATURES WILL AGAIN BE ON THE WARM SIDE WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.

WITH THE LOSS OF DAYTIME HEATING MONDAY NIGHT MOST OF THE DIURNALLY
DRIVEN CONVECTION WILL DIMINISH IN COVERAGE...ALTHOUGH A FEW STORMS
MAY CONTINUE LATE INTO THE EVENING...ESPECIALLY ACROSS PORTIONS OF
THE SOUTHERN TIER. AT THE SAME TIME A COLD FRONT OVER THE UPPER
GREAT LAKES WILL BE ADVANCING TOWARD THE REGION AND BE LOCATED WEST
OF NEW YORK STATE BY TUESDAY MORNING. THAT SAID...MOST OF THE NIGHT
LOOKS TO REMAIN DRY...WITH PRECIP CHANCES STARTING TO INCREASE A BIT
ACROSS WESTERN NEW YORK TOWARD TUESDAY MORNING. ANOTHER MILD
NIGHT CAN BE EXPECTED WITH LOWS IN THE MID TO UPPER 60S FOR MOST
LOCATIONS THANKS TO DEEP SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING
COLD FRONT.

LATEST GUIDANCE PACKAGE HAS THE COLD FRONT NOW MOVING A BIT SLOWER
THAN IN PREVIOUS RUNS. THIS IS MOST LIKELY DUE TO MOST OF THE MODELS
NOW COMING INTO AGREEMENT ON THE DEVELOPMENT OF LOW PRESSURE
SOMEWHERE IN THE OHIO VALLEY ALONG THE FRONT AND THEN TRACKING IT
NORTHEAST ALONG THE BOUNDARY WHICH WOULD SLOW IT DOWN A LITTLE.
THAT SAID...IT NOW APPEARS IT WILL TAKE THE BULK OF THE DAY TUESDAY
FOR THE COLD FRONT TO SWEEP ACROSS THE REGION WITH SHOWERS AN
THUNDERSTORMS LIKELY...WITH LOWER CHANCE POPS BY LATER IN THE DAY
ACROSS WESTERN NEW YORK. HIGH PRECIPITABLE WATER VALUES OF 1.7"-1.9"
TUESDAY AFTERNOON OFFER THE RISK OF HEAVY DOWNPOURS WITH ANY
THUNDERSTORM. SBCAPES OVER 1000 J/KG COMBINED WITH LIFTED INDEX
VALUES AT -4C TO -5C ALSO POINT TO THE POSSIBILITY OF STORMS. THE
MAIN DIFFERENCES FROM MONDAY ARE THAT 0-6KM BULK SHEAR VALUES LOOK
TO BE IN THE 40-45KT RANGE...AND ALSO HAVE THE SURFACE COLD FRONT
CROSSING THE FORECAST AREA WHICH WILL SERVE AS THE FOCAL POINT FOR
STORMS TO FIRE ALONG. ALL THIS SAID...LOOKS AS THOUGH THERE COULD BE
SOME STRONG STORMS...WITH A FEW STORMS POSSIBLY REACHING SEVERE
LIMITS. MAIN THREATS APPEAR TO BE GUSTY WINDS ASSOCIATED WITH BOWING
LINE SEGMENTS AND MARGINALLY SEVERE HAIL. ANOTHER WARM DAY ON TAP
WITH HIGHS IN THE UPPER 70S TO LOWER 80S.

THE COLD FRONT WILL SLIDE SOUTH AND EAST OF THE FORECAST AREA
TUESDAY EVENING...TAKING THE SHOWERS AND STORMS WITH IT. ALTHOUGH A
FEW SHOWERS WILL STILL BE POSSIBLE DURING THE EVENING ACROSS EASTERN
AREAS...BUT EVEN HERE THINGS WILL DRY OUT LATER TUESDAY NIGHT AS
SURFACE HIGH PRESSURE STARTS TO BUILD EAST ACROSS NEW YORK STATE.
LOWS WILL BE GENERALLY IN THE UPPER 50S TO LOWER 60S.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE WILL BUILD ACROSS THE
REGION WEDNESDAY AND THURSDAY BRINGING IN DRIER AIR AND TEMPERATURES
THAT WILL STILL AVERAGE AT OR JUST A BIT ABOVE NORMAL FOR EARLY
SEPTEMBER. HIGH PRESSURE WILL THEN SLIDE OFF THE NEW ENGLAND COAST
BY FRIDAY. THIS WILL PROVIDE MAINLY DRY CONDITIONS THROUGH
MIDWEEK...BEFORE THE NEXT FRONTAL SYSTEM APPROACHES FOR LATE IN THE
WEEK AND EARLY WEEKEND. TEMPERATURES WILL BE A BIT ABOVE SEASONAL
NORMALS WITH HIGHS IN THE UPPER 70S TO LOW 80S AND LOWS IN THE LOWER
60S.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
A STEADY AREA OF LIGHT RAIN WILL CONTINUE TO MOVE SLOWLY EAST ACROSS
THE SOUTHERN TIER...FINGER LAKES...AND CENTRAL NY THROUGH MIDDAY.
CIGS/VSBY WILL REMAIN VFR IN MANY AREAS...ALTHOUGH A FEW POCKETS OF
MODERATE RAIN WILL PRODUCE MVFR VSBY AT TIMES. EXPECT POCKETS OF
MVFR/IFR CIGS TO ALSO BECOME A LITTLE MORE COMMON BY MID MORNING
ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND FINGER LAKES. THE
LOWER ELEVATIONS ON THE LAKE PLAINS SHOULD STAY MAINLY VFR DUE IN
PART TO SSW DOWNSLOPE FLOW.

THE STEADIER SHOWERS WILL DIMINISH FROM NORTHWEST TO SOUTHEAST
DURING THE LATE MORNING TO EARLY AFTERNOON. EXPECT CIGS/VSBY TO
IMPROVE TO MAINLY VFR EXCEPT IN ANY HEAVIER SHOWERS AND WIDELY
SCATTERED THUNDERSTORMS THAT DEVELOP WITH DAYTIME HEATING THIS
AFTERNOON. BY MID AFTERNOON THESE SHOULD BE CONFINED TO THE SOUTHERN
TIER AND CENTRAL NY WITH THE REMAINDER OF THE AREA DRY.

TONIGHT ANY SHOWERS AND SCATTERED THUNDER ACROSS THE SOUTHERN TIER
WILL DIMINISH DURING THE EVENING. MAINLY VFR DURING THE EVENING WILL
GIVE WAY TO INCREASING AMOUNTS OF IFR IN LOW STRATUS OVERNIGHT WITH
EXTENSIVE LOW LEVEL MOISTURE FIELDS. EXPECT STRATUS TO FORM FIRST
ACROSS HIGHER TERRAIN...BUT MAY SPREAD TO THE LOWER ELEVATIONS OF
WESTERN NY AS WELL AFTER ABOUT 09Z. AREAS OF FOG AND IFR VSBY ARE
LIKELY ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND FINGER
LAKES AS WELL WHERE THE LOW STRATUS INTERSECTS THE HILLS.

OUTLOOK...
MONDAY...VFR/MVFR IN SCATTERED SHOWERS AND THUNDERSTORMS.
TUESDAY...SHOWERS AND THUNDERSTORMS LIKELY WITH ASSOCIATED BRIEF
MVFR/IFR. SOME STORMS MAY BE STRONG.
WEDNESDAY AND THURSDAY...VFR.

&&

.MARINE...
MODERATE SOUTHERLIES WILL CONTINUE TO PRODUCE MARGINAL SMALL CRAFT
ADVISORY CONDITIONS AT THE NORTHEAST END OF LAKE ONTARIO FROM GALLOO
ISLAND TO CAPE VINCENT THROUGH EARLY TO MID MORNING BEFORE
DIMINISHING. LOW PRESSURE WILL MOVE ACROSS SOUTHERN QUEBEC TODAY
WITH WINDS BECOMING MORE SOUTHWEST ON THE LOWER LAKES. THIS WILL
ALLOW WINDS TO INCREASE SOMEWHAT ON LAKE ERIE...WITH MARGINAL SMALL
CRAFT ADVISORY CONDITIONS FROM MID TO LATE MORNING THROUGH MID TO
LATE AFTERNOON.

THE PRESSURE GRADIENT RELAXES ACROSS THE LOWER LAKES TONIGHT AS LOW
PRESSURE DISSIPATES OVER SOUTHEAST QUEBEC. THIS WILL ALLOW WINDS AND
WAVES TO SUBSIDE.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LEZ040-
         041.
         SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
         LOZ045.

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...JM
LONG TERM...JM/WCH
AVIATION...HITCHCOCK
MARINE...HITCHCOCK





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