Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 251927
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
327 PM EDT MON MAY 25 2015

.SYNOPSIS...
PERSISTENT HIGH PRESSURE ANCHORED OFF THE EAST COAST WILL KEEP A
WARM AIR MASS OVER THE REGION. INCREASING HUMIDITY WILL BRING THE
RISK FOR SOME NEEDED SHOWERS AND THUNDERSTORMS THROUGH MID WEEK.

&&

.NEAR TERM /THROUGH TUESDAY/...
A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION TONIGHT. ANY
SPOTTY CONVECTION TIED TO AFTERNOON HEATING WILL DIMINISH EARLY
TONIGHT. A FEW POP UP SHOWERS CAN NOT BE RULED OUT IN THE HUMID
AIR MASS...BUT THINK THE BULK OF THE TONIGHT PERIOD WILL BE
RAINFREE AND RATHER HUMID WITH OVERNIGHT LOWS GENERALLY IN THE MID
60S. THESE VALUES WILL BE A SOLID 10 DEGREES F ABOVE NORMAL LATE
MAY NORMALS.

A DEEP SOUTHWESTERLY FLOW WILL CONTINUE TO ADVECT MOIST AIR INTO
THE REGION TUESDAY. HAVING A RATHER HARD TIME FINDING ANY BIG
TRIGGER FOR AFTERNOON CONVECTIVE DEVELOPMENT ON TUESDAY...THOUGH
WITH DEW POINTS RISING WELL INTO THE 60S (AWAY FROM THE LAKES)
AND EXPECTED HEATING OF TEMPERATURES WELL INTO THE UPPER 70S AND
LIKELY EVEN TO THE MID 80S...ANY SUBTLE FEATURE COULD DO THE
TRICK WITH AN UNCAPPED ATMOSPHERE. LAKE BREEZE BOUNDARIES WILL
LIKELY BE THE PRIME FOCUS AREAS FOR AFTERNOON CONVECTION...
THEREFORE EXPECT CHANCES FOR SHOWERS/THUNDERSTORMS TO INCREASE
AWAY FROM THE LAKES DURING THE AFTERNOON. SEVERE THREAT LOOKS
LIMITED AS MID LEVEL LAPSE RATES RATHER STABLE WITH GENERALLY TALL
BUT THIN CAPES AND RATHER WEAK SHEAR PROFILES.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
ANY LINGERING CONVECTION FROM TUESDAY AFTERNOON SHOULD TAPER OFF
TUESDAY NIGHT WITH THE LOSS OF DIURNAL INSTABILITY COUPLED WITH THE
ARRIVAL OF SHORTWAVE RIDGING ALOFT THAT SHOULD PROVIDE AN EFFECTIVE
CAP. NONETHELESS...IT WILL BE QUITE THE STICKY SUMMER NIGHT FOR
WESTERN AND NORTH-CENTRAL NEW YORK AS RETURN FLOW AROUND HIGH
PRESSURE ANCHORED OFF THE MID-ATLANTIC COAST WILL PROVIDE AN AMPLE
SUPPLY OF WARM AND MOIST AIR. WITH DEWPOINTS HANGING IN THE LOW-
60S...DON`T EXPECT OVERNIGHT LOWS TO DIP LOWER THAN THE MID 60S
ACROSS MOST AREAS.

CONVECTIVELY SPEAKING...WEDNESDAY WILL LIKELY BE THE MOST ACTIVE DAY
OF THIS WEEK. RETURN FLOW WILL CONTINUE TO PUMP THETA-E RICH AIR
ACROSS THE REGION WITH PLENTY OF LOW-LEVEL INSTABILITY. IN ADDITION
THERE WILL BE A MORE FAVORABLE SYNOPTIC REGIME WITH SURFACE/MID-
LEVEL TROUGHING JUST UPSTREAM ACROSS THE CENTRAL GREAT
LAKES...PROVIDING A PATH FOR DOWNSTREAM SHORTWAVE ENERGY ACROSS THE
OHIO VALLEY TO MOVE ACROSS THE LOWER GREAT LAKES AND THIS COUPLED
WITH A WEAK SURFACE TROUGH PROGGED TO SLIDE ACROSS THE LOWER GREAT
LAKES SHOULD PROVIDE THE IMPETUS FOR WIDESPREAD CONVECTION...LIKELY
INITIATING ON LAKE BREEZE BOUNDARIES EARLY IN THE AFTERNOON AND
MOVING INLAND WITH THE SURFACE TROUGH AND BACKING MID-LEVEL FLOW.

ALTHOUGH CONVECTION SHOULD BE FAIRLY WIDESPREAD ON WEDNESDAY...THE
SEVERE THREAT SHOULD BE MARGINAL AT BEST. ALTHOUGH SURFACE-BASED
CAPES ARE PROGGED TO CLIMB UPWARDS OF 1500 J/KG...MID-LEVEL LAPSE
RATES ARE MODEST AND 0-6KM BULK SHEAR ONLY TOPS OUT AROUND 30KT WITH
A FAIRLY STRAIGHT HODOGRAPH. IN FACT THE MAIN THREAT OF THE DAY WILL
BE HEAVY RAIN...AND GIVEN THE RECENT DRY CONDITIONS...THAT SHOULD BE
QUITE WELCOME.

IT IS POSSIBLE THAT WE MAY SEE ANOTHER ROUND OF SCATTERED CONVECTION
WEDNESDAY NIGHT AS THE H5 TROUGH UPSTREAM MAKES ITS WAY ACROSS THE
FORECAST AREA. DEPENDING ON HOW QUICKLY THIS FEATURE CROSSES THE
REGION...IT MAY CONTRIBUTE TO ANOTHER ROUND OF ENHANCED CONVECTION
THURSDAY AFTERNOON. CURRENT TIMING OF THE SHORTWAVE INDICATED BY
THE MODELS INDICATES THAT THE EASTERN HALF OF THE FORECAST AREA HAS
THE BEST SHOT AT SHOWERS AND THUNDERSTORMS THURSDAY...HOWEVER WILL
NOT RULE OUT AT LEAST A FEW SHOWERS/THUNDERSTORMS FIRING ON THE LAKE
ERIE LAKE BREEZE AS WELL. ANY CONVECTION SHOULD WIND DOWN THURSDAY
NIGHT AS THE SHORTWAVE MOVES OFF TO OUR EAST AND ANY DIURNAL
INSTABILITY DIMINISHES AFTER NIGHTFALL.

REGARDING TEMPERATURES...WARM AND MUGGY WILL BE THE RULE FOR MUCH OF
THE WEEK AS THE AFOREMENTIONED RETURN FLOW WILL REMAIN FIRMLY IN
PLACE THROUGH THE PERIOD...KEEPING 850MB TEMPS IN THE 12C-15C RANGE
THROUGHOUT THE WEEK. THIS WILL TRANSLATE TO HIGHS IN THE UPPER 70S
TO LOWER 80S AND THIS COUPLED WITH SURFACE DEWPOINTS THAT WILL
REMAIN THE THE UPPER 50S TO LOWER 60S WILL KEEP IT FEELING QUITE
SUMMER-LIKE INDEED AS LOWS WILL ONLY DROP INTO THE LOWER 60S TUESDAY
AND WEDNESDAY NIGHTS. SLIGHTLY DRIER AIR IN THE WAKE OF THURSDAY`S
SHORTWAVE MAY ALLOW READINGS THURSDAY NIGHT TO RUN A COUPLE OF
DEGREES COOLER...IN THE UPPER 50S TO AROUND 60.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
SURFACE/WEAK UPPER LEVEL RIDGING RETURNS TO THE LOWER GREAT LAKES ON
FRIDAY PLACING A DAMPER ON MOST CONVECTION. THINGS SHOULD BECOME
MUCH MORE ACTIVE THOUGH AS WE MOVE INTO THE WEEKEND. A POTENT UPPER
LEVEL VORT MAX DROPPING OUT OF THE CANADIAN ARCTIC WILL CARVE OUT
A TROUGH ACROSS THE CANADIAN PRAIRIE PROVINCES LATE THIS WEEK.
THIS TROUGH IS PROGGED TO CROSS NORTHERN ONTARIO AND MOVE INTO
EASTERN QUEBEC SATURDAY. THOUGH TIMING BETWEEN THE GLOBAL MODELS
DIFFERS SLIGHTLY...THE GENERAL CONSENSUS IS FOR THE THIS FEATURE
TO PUSH A STRONG COLD FRONT ACROSS THE FORECAST AREA SATURDAY OR
SATURDAY EVENING. GIVEN STRONG SYNOPTIC FORCING ASSOCIATED WITH
THE FRONT...EXPECT WIDESPREAD SHOWERS/THUNDERSTORMS ON
SATURDAY/SATURDAY NIGHT AS THE FRONT MOVES THROUGH. WHILE IT WILL
REMAIN QUITE WARM AND MUGGY AHEAD OF SATURDAY`S FRONT...THINGS
CONSIDERABLY COOLER AND DRIER ON SUNDAY AS THE FRONT SETTLES TO
OUR SOUTH...YIELDING PLENTY OF SUNSHINE AND HIGHS IN THE UPPER 60S
TO AROUND 70.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
AN INCREASINGLY MOIST AIRMASS WILL ALLOW FOR SCATTERED SHOWERS
THROUGH THIS AFTERNOON...BRINGING NOTHING MORE THAN A BRIEF VSBY
RESTRICTION IN THE HEAVIEST SHOWERS. DIURNAL HEATING COULD BRING
SOME ISOLATED THUNDERSTORMS...BUT NOT WIDESPREAD ENOUGH TO WARRANT
A MENTION IN THE TAF AS ANY ACTIVITY WILL LIKELY BE TIED TO A
LAKE BREEZE BOUNDARY. SOUTHWEST WINDS WILL CONTINUE TO GUST TO
AROUND 25 KNOTS UNTIL DIURNAL HEATING IS LOST THIS EVENING.

TONIGHT...VFR CONDITIONS SHOULD REMAIN IN PLACE ACROSS THE REGION
ALTHOUGH THERE WILL BE THE CHANCE OF A SHOWER OR THUNDERSTORM
DURING THE FIRST HALF OF THE NIGHT. THE EXCEPTION TO THE VFR
CONDITIONS COULD BE OVER THE WRN SOUTHERN TIER WHERE CIGS MAY
LOWER TO IFR/MVFR LEVELS AFTER 06Z.

OUTLOOK...
TUESDAY THROUGH SATURDAY...MAINLY VFR WITH ISOLD/SCT -SHRA/TSRA.

&&

.MARINE...
THE CLOSE PROXIMITY OF SPRAWLING HIGH PRESSURE ANCHORED OFF THE EAST
COAST WILL KEEP A WEAK PRESSURE GRADIENT OVER LAKES ERIE AND ONTARIO
TONIGHT AND TUESDAY...WHICH WILL BE SUPPORTIVE OF GENTLE TO MODERATE
WINDS AND NEGLIGIBLE WAVES.

SOUTHWEST WINDS WILL FRESHEN SOMEWHAT ON LAKE ERIE ON WEDNESDAY
THOUGH...AND THIS MAY PROMOTE WAVES TO APPROACH SCA LEVELS.

WHILE WINDS AND WAVES WILL LIKELY REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS ON TUESDAY AND WEDNESDAY...THERE WILL BE THE RISK FOR SOME
THUNDERSTORMS WHICH COULD BRING LOCALLY HIGHER WINDS AND WAVES.

&&

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

&&

$$

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


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