Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 260333
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1133 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/...
SHOWERS WILL TAPER OFF THIS EVENING WITH STEADIER SHOWERS
ASSOCIATED WITH THE LEADING EDGE OF A 40-50 LLJ EXITING INTO NEW
ENGLAND. UPSTREAM OBS SUPPORT THE MAJORITY OF HIGH RES GUIDANCE
WHICH KEEPS OUR REGION MOSTLY DRY OVERNIGHT. THIS IS ALSO
SUPPORTED BY WINDS WHICH SHOULD DIMINISH BEHIND THE EXITING
SHORTWAVE AND LLJ AND PROMOTE DRYING. WHEN WINDS DIMINISHING LATE
TONIGHT...THERE MAY BE SOME PATCHY FOG NNE OF THE LAKES WITH MOIST
DEW POINTS OVERRUNNING THE RELATIVELY COOL LAKE WATERS. THIS
SHOULD PRIMARILY IMPACT CANADA...BUT MAY SNEAK INTO THE NORTH
COUNTRY. OTHERWISE...EXPECT WARM TEMPERATURES OVERNIGHT WITH LOWS
IN THE 60S.

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 /04Z TUESDAY THROUGH SATURDAY/...
ANY LINGERING SHOWERS SHOULD TAPER OFF THROUGH 06Z...WITH DRY
WEATHER EXPECT THROUGH 15Z TUESDAY. EXPECT MOSTLY VFR
CONDITIONS...BUT THERE IS A CHANCE THAT FOG OR LOW CIGS WILL
DEVELOP NNE OF LAKE ONTARIO NEAR ART LATE TONIGHT AND TUESDAY
MORNING. ELSEWHERE THERE IS ONLY A SMALL POTENTIAL FOR MVFR OR
LOWER CONDITIONS IF LOCALIZED FOG/CIGS DEVELOP.

INSTABILITY SHOWERS AND THUNDERSTORMS WILL DEVELOP IN THE
AFTERNOON. THESE WILL BE MOST WIDESPREAD NEAR JHW...BUT COULD
IMPACT ANY TAF SITE DURING THE AFTERNOON HOURS.

OUTLOOK...
TUESDAY NIGHT 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
OVERNIGHT 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...APFFEL/TMA
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/TMA


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