Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 132003
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
403 PM EDT SUN JUL 13 2014

.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL TAPER OFF FROM WEST TO EAST THIS
EVENING AS A TROUGH CROSSES THE REGION...HOWEVER SHOWERS AND
THUNDERSTORMS WILL LIKELY DEVELOP AGAIN TUESDAY AHEAD OF AN
APPROACHING COLD FRONT. THIS COLD FRONT WILL MOVE THROUGH TUESDAY
NIGHT...USHERING IN COOLER AND DRIER AIR FOR THE REMAINDER OF THE
COMING WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
AN ANALYSIS OF SURFACE OBSERVATIONS THIS AFTERNOON INDICATES THAT
THE AXIS OF THE SURFACE TROUGH IS ON OUR DOORSTEP. A WEAK FRONTAL
BOUNDARY RESTS WITHIN THIS TROUGH...THOUGH THE BOUNDARY IS
FUNCTIONALLY DIFFERENTIATES DEWPOINTS RATHER THAN TEMPERATURES AS THE
TEMPERATURES TO OUR WEST ARE ACTUALLY SLIGHTLY WARMER THANKS TO
INCREASING INSOLATION.  REGIONAL RADAR AND SATELLITE IMAGERY SHOW
THE SHARP DEMARCATION BETWEEN THE MOIST AIR TO THE EAST OF THE FRONT
AND THE DRIER AIR INTRUDING FROM THE WEST WITH AN AREA OF SHOWERS
AND THUNDERSTORMS JUST AHEAD OF THE FRONT. THE SOUTHERN END OF THIS
LINE HAS SHOWN SIGNS OF STRENGTHENING THIS AFTERNOON...HOWEVER IT
WILL BE EXITING ALLEGANY COUNTING WITHIN THE NEXT HOUR.

CONDITIONS WILL IMPROVE RAPIDLY BEHIND THE FRONT AS THE
AFOREMENTIONED DRIER AIR ADVECTS INTO THE REGION. IT SHOULD DRY OUT
NICELY THIS EVENING WITH CLOUD COVER DIMINISHING OVERALL. AS
MENTIONED ABOVE...TEMPERATURES BEHIND THE FRONT ARE NOT MUCH COOLER
AND ONLY EXPECT LOWS TO FALL INTO THE 60S.

FOR MONDAY...WE SHOULD SEE DRY CONDITIONS OF MUCH OF THE DAY WITH
TEMPERATURES RISING TOWARDS THE 80 DEGREE MARK. BY LATE AFTERNOON
HOWEVER...SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP AS LOW
LEVEL FLOW BACKS TO THE SOUTH AND HIGHER THETA-E AIR BEGINS TO
ADVECT BACK INTO THE FORECAST AREA.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
MONDAY NIGHT AND TUESDAY WILL FEATURE CONTINUED CHANCES FOR SHOWERS
AND THUNDERSTORMS. INITIALLY AN UNSTABLE AIRMASS WILL REMAIN OVER THE
EASTERN GREAT LAKES REGION...WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS. AS A COLD FRONT...ALONG WITH A POTENT UPPER LEVEL
SHORTWAVE CROSS THE EASTERN GREAT LAKES LATER MONDAY NIGHT AND EARLY
TUESDAY EXPECT INCREASING NUMBERS OF CONVECTIVE SEGMENTS.

THOUGH THERMODYNAMICS (LITTLE CAPE/POOR LAPSE
RATES/EARLY IN THE DAY FRONTAL PASSAGE) ARE NOT THAT IMPRESSIVE WITH THIS
SYSTEM THERE WILL BE IMPRESSIVE KINEMATICS (60+ KNOTS OF 0-6 KM BULK
SHEAR) AND DYNAMICS (UPPER LEVEL SHORTWAVE/RIGHT ENTRANCE REGION OF
250 HPA JET) THAT WILL MAINTAIN THUNDERSTORM POTENTIAL...WHICH COULD
TRANSPORT STRONGER WIND GUSTS DOWN TO THE SURFACE. THIS IS STILL LOW
CONFIDENCE AND NO ENHANCED WORDING WILL BE ADDED TO THE FORECAST
GRIDS.

IT WILL REMAIN MILD AND MUGGY MONDAY NIGHT WITH LOWS IN THE LOWER TO
MID 60S. TUESDAY...SUMMER`S WARMTH TO THE EAST WITH HIGHS IN THE
UPPER 70S WILL FADE AS LOW 70S OVER WESTERN NEW YORK BEHIND THE COLD
FRONT EXPAND EASTWARD.

BY TUESDAY NIGHT THE COLD FRONT WILL BE EXITING TO THE SOUTH AND
EAST OF THE CWA. CLOUDS WILL LIKELY REMAIN THROUGH THE OVERNIGHT AS
THE UPPER LEVEL LOW FROM OVER THE WESTERN GREAT LAKES NEARS THE
REGION.

ON WEDNESDAY AN UNSEASONABLY COOL AIRMASS WILL ENTER THE EASTERN
GREAT LAKES AS THE CENTER OF THE UPPER LEVEL TROUGH OF LOW PRESSURE
ADVANCES EASTWARD. TEMPERATURES AT 850 HPA WILL DROP TO AROUND +7C
OVER LAKE ONTARIO AND +8C OVER LAKE ERIE. LAKE TEMPERATURES ARE
19-20C ON LAKE ONTARIO AND 22C ON LAKE ERIE. THIS COOL AIRMASS OVER
THE WARM LAKE WATERS WILL LIKELY TRIGGER LAKE EFFECT
CLOUDINESS...AND ON A WESTERLY FLOW POSSIBLY LAKE EFFECT RAIN
SHOWERS. WILL PLACE HIGHER CHANCES FOR RAIN SHOWERS IN THE TYPICAL
HIGHER TERRAIN EAST OF BOTH LAKES WHERE AN ADDITIONAL COMPONENT OF
OROGRAPHIC LIFT WILL BRING HIGH CHANCES FOR RAIN SHOWERS. ELSEWHERE
WILL CONTINUE WITH LOW CHANCE POP FOR SCATTERED DAYTIME INSTABILITY
SHOWERS UNDER THE UPPER LEVEL LOW.

WEDNESDAY NIGHT EXPECT A REDUCTION IN PRECIPITATION ACROSS THE
REGION WITH THE LOSS OF DAYTIME HEATING. ANY CLEARING WILL BRING
COOL OVERNIGHT LOWS IN THE 40S. HOWEVER ANY LINGERING LAKE
CLOUDINESS WILL LIMIT THE RADIATIONAL LOSS OF HEAT AND KEEP
OVERNIGHT LOWS IN THE 50S WHERE LAKE CLOUDS PERSIST THE LONGEST.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE ANOMALOUS RIDGE/TROUGH OVER NORTH AMERICA MID WEEK WILL BE IN
THE PROCESS OF BREAKING DOWN AS SEVERAL SHORTWAVES BREAK DOWN THE
WEST COAST RIDGE EARLY/MIDWEEK. IN RESPONSE THE UPPER LEVEL LOW OVER
THE GREAT LAKES WILL LIFT NORTHWARD TOWARDS CANADA WITH WARMER AIR
PUSHING NORTHWARD STARTING THURSDAY. AN ISOLATED SHOWER WILL STILL
BE POSSIBLE THURSDAY WITH THE STILL LINGERING UPPER LEVEL
TROUGH...AND AIR TEMPERATURES STILL RUNNING BELOW NORMAL.

FRIDAY AND SATURDAY WILL FEATURE A WARMING TREND...AND DRY WITH AN
AREA OF HIGH PRESSURE IN CONTROL...AND UPPER LEVEL RIDGING ALOFT. HOWEVER
PIECES OF ENERGY WILL INFILTRATE INTO THE RIDGE...AND AS THE SURFACE
HIGH SLIDES EASTWARD A RETURN SOUTHERLY FLOW OF INCREASING MOISTURE
WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS BACK INTO THE
FORECAST FOR NEXT SUNDAY.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
SHOWERS AND THUNDERSTORMS ARE CROSSING THE NIAGARA FRONTIER ATTM AND
SHOULD BE CLEARING THE AREA WITHIN THE NEXT 1-2 HOURS AS A SURFACE
TROUGH JUST TO OUR WEST CROSSES THE AREA. EXPECT RAPID IMPROVEMENT
TO VFR BEHIND THIS TROUGH AS UPSTREAM WV IMAGERY INDICATES MUCH
DRIER AIR ALOFT ADVECTING TOWARDS THE REGION.

SHOWERS AND THUNDERSTORMS WILL CONTINUE TO MOVE EAST ACROSS THE
GENESEE VALLEY AND FINGER LAKES THIS AFTERNOON...EXITING THE NORTH
COUNTRY DURING THE EVENING HOURS. AM CURRENTLY MONITORING RADAR
TRENDS ACROSS THE FINGER LAKES AND SOUTHERN TIER AS CONVECTIVE LINE
IS CONSOLIDATING AND HAS THE POTENTIAL TO BECOME STRONG SEVERE OVER
THE NEXT COUPLE OF HOURS...HOWEVER THIS STRONGER CONVECTION SHOULD
NOT IMPACT KROC/KART.

LOOK FOR CONDITIONS TO IMPROVE TO VFR ACROSS THE ENTIRE FORECAST
AREA OVERNIGHT AS AFOREMENTIONED DRIER AIR ALOFT MOVES IN FROM THE
WEST. ONE POSSIBLE EXCEPTION WILL BE ACROSS THE HIGHER ELEVATIONS OF
THE SOUTHERN TIER WHERE SCT/BKN IFR CIGS MAY DEVELOP
OVERNIGHT...DEPENDING ON AMOUNT OF CLEARING IN THE HIGHER LEVELS AND
SUBSEQUENT RADIATIVE COOLING THAT TAKES PLACE. OTHERWISE VFR
CONDITIONS SHOULD PREVAIL THROUGH THE REST OF THE FORECAST
PERIOD...THOUGH THERE WILL BE A CHANCE FOR SHOWERS AND
THUNDERSTORMS RE-DEVELOPING MONDAY AFTERNOON.


OUTLOOK...
MONDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS IN
THE AFTERNOON.
TUESDAY...VFR/MVFR IN SCATTERED SHOWERS AND THUNDERSTORMS.
WEDNESDAY THROUGH FRIDAY...MAINLY VFR.

&&

.MARINE...
GUSTY SOUTHWESTERLY WINDS WILL TAPER OFF THIS EVENING AND WAVES WILL
SUBSIDE TONIGHT AS A TROUGH OF LOW PRESSURE PULLS AWAY FROM THE
AREA...RELAXING THE PRESSURE GRADIENT. GENERALLY LIGHT FLOW WILL THEN
PERSIST OVER THE LAKES THROUGH MONDAY NIGHT BEFORE SOUTHWESTERLY
FLOW STRENGTHENS AGAIN ON TUESDAY IN ADVANCE OF AN APPROACHING COLD
FRONT...LIKELY REQUIRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES FOR
LAKE ERIE. WINDS WILL TAPER OFF TUESDAY NIGHT INTO WEDNESDAY BEHIND
THE FRONT AS HIGH PRESSURE BUILDS INTO THE LOWER GREAT LAKES.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LEZ020-
         040-041.
         SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
         LOZ030-042>045.

&&

$$

SYNOPSIS...WOOD
NEAR TERM...WOOD
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...WOOD
MARINE...WOOD







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