Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 301351
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
951 AM EDT SAT AUG 30 2014

.SYNOPSIS...
HIGH PRESSURE WILL DRIFT OFF THE NEW ENGLAND COAST TODAY AND PROVIDE
ANOTHER MAINLY DRY DAY WITH JUST A SMALL CHANCE OF A SPOTTY SHOWER
LATE THIS AFTERNOON ACROSS WESTERN NY. A TROUGH OF LOW PRESSURE WILL
THEN CROSS THE REGION TONIGHT THROUGH THE FIRST HALF OF SUNDAY WITH
A BETTER CHANCE OF SHOWERS AND SCATTERED THUNDERSTORMS. MONDAY WILL
BE DRY THE VAST MAJORITY OF THE TIME...ALTHOUGH A FEW WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE WITH A WARM AND
HUMID AIRMASS STILL IN PLACE.

&&

.NEAR TERM /THROUGH TONIGHT/...
RADAR SHOWS A RATHER SPARSE LINE OF SHOWERS AND THUNDERSTORMS
WHICH APPEARS TO BE ASSOCIATED WITH A WARM FRONT LIFTING FROM SW-
NE ACROSS OUR REGION. THESE WILL MOVE ACROSS LAKE ERIE THROUGH
EARLY AFTERNOON...AND MAY CLIP FAR WESTERN NEW YORK. AFTER
THIS...EXPECT A BRIEF PERIOD OF SUBSIDENCE BEHIND THIS...WITH
SOUTHERLY WINDS HELPING TO MIX LOW LEVEL MOISTURE ACROSS THE
NIAGARA FRONTIER FOR THE REMAINDER OF THE AFTERNOON.

SURFACE HIGH PRESSURE WILL CONTINUE TO DRIFT SLOWLY OFF THE NEW
ENGLAND COAST THIS AFTERNOON...WITH SOUTHERLY RETURN FLOW IN ITS WAKE
ACROSS THE LOWER LAKES. THIS WILL ALLOW FOR A STEADY INCREASE IN
LOW LEVEL MOISTURE WITH SURFACE DEWPOINTS RISING INTO THE MID 60S
ACROSS WESTERN NY. THE INCREASING BOUNDARY LAYER MOISTURE AND
DIURNAL HEATING WILL CONTRIBUTE TO SBCAPE OF AROUND 1500J/KG BY
MID AFTERNOON ACROSS WESTERN NY. WARM MID LEVEL TEMPS MAY KEEP
SOME CINH IN THE PROFILE INTO THE AFTERNOON...AND WITH ONLY WEAK
SYNOPTIC SCALE SUPPORT EXPECT ANY CONVECTION TO REMAIN ISOLATED IN
NATURE THIS AFTERNOON. A VERY WEAK MID LEVEL SHORTWAVE WILL CROSS
WESTERN NY...AND THIS COMBINED WITH TERRAIN INDUCED CONVERGENCE
ACROSS THE SOUTHERN TIER AND WESTERN FINGER LAKES MAY TRIGGER AN
ISOLATED SHOWER OR THUNDERSTORM DURING THE MID TO LATE
AFTERNOON...BUT MOST AREAS SHOULD REMAIN DRY.

OTHERWISE EXPECT SOME INCREASE IN CLOUD COVER DURING THE AFTERNOON
WITH INCREASING LOW/MID LEVEL MOISTURE. 850MB TEMPS RISING TO AROUND
+17C WILL SUPPORT HIGHS IN THE MID TO UPPER 80S ACROSS THE LOWER
ELEVATIONS OF WESTERN NY WITH SOME ADDED BOOST FROM SSW DOWNSLOPE
FLOW. HIGHS WILL GENERALLY BE IN THE LOWER 80S ACROSS THE HIGHER
TERRAIN AND EAST OF LAKE ONTARIO.

THIS EVENING ANY WIDELY SCATTERED DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS WHICH DO DEVELOP ACROSS WESTERN NY WILL GRADUALLY
WEAKEN AND DISSIPATE BY MID TO LATE EVENING. OVERNIGHT THE CHANCES
FOR SOMEWHAT MORE WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS
WILL INCREASE AS A MID LEVEL TROUGH MOVES INTO THE CENTRAL LAKES.
HEIGHT FALLS AND DPVA AHEAD OF THE TROUGH WILL PROVIDE INCREASING
LARGE SCALE ASCENT...AND UPPER LEVEL DIVERGENCE WILL INCREASE IN THE
RIGHT ENTRANCE REGION OF AN 80 KNOT UPPER LEVEL JET. AT THE SURFACE
A PRE-FRONTAL TROUGH WILL ENTER THE LOWER LAKES LATE TONIGHT AND
PROVIDE LOW LEVEL CONVERGENCE. A BELT OF 30-35 KNOT FLOW IN THE
900-700MB LAYER WILL ALSO AID IN ORGANIZING CONVERGENCE AND MOISTURE
TRANSPORT. PWAT RISES TO AROUND 1.8 INCHES...SO MOISTURE WILL BE IN
AMPLE SUPPLY.

GIVEN THE SUFFICIENT FORCING AND GOOD MOISTURE COMING TOGETHER...
WILL CONTINUE TO INCREASE POPS TO HIGH LIKELY FOR LATER TONIGHT.
ENOUGH INSTABILITY REMAINS IN PROFILES TO SUPPORT SCATTERED
THUNDERSTORMS AS WELL. A FEW OF THE STRONGER STORMS MAY PRODUCE
LOCALLY HEAVY DOWNPOURS GIVEN THE HIGH PWAT ENVIRONMENT AND
TALL/SKINNY CAPE PROFILES. UNFAVORABLE TIME OF DAY...LIMITED
INSTABILITY AND MARGINAL SHEAR PROFILES SHOULD PREVENT CONVECTION
FROM BECOMING TOO STRONG. PREFER THE SOMEWHAT SLOWER TIMING OF THE
GFS AND SREF MEAN OVER THE FASTER NAM SOLUTION...WHICH APPEARS TO
BRING AN INITIAL SHORTWAVE AND CONVECTION INTO THE DEPARTING MID
LEVEL RIDGE TOO FAST THIS EVENING.

A WARM/MUGGY AIRMASS COMBINED WITH INCREASING CLOUDS AND A SSW
BREEZE WILL KEEP TEMPERATURES VERY MILD OVERNIGHT...WITH LOWS IN THE
LOWER 70S ON THE LAKE PLAINS OF WESTERN NY AND MID TO UPPER 60S
ELSEWHERE.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
BEST CHANCES FOR PRECIPITATION DURING THIS PERIOD WILL BE ON
SUNDAY...WITH CHANCES LESSENING FROM WEST TO EAST AS THE DAY
PROGRESSES. THEN EXPECT PLENTY OF USABLE DRY TIME FROM SUNDAY NIGHT
INTO MONDAY NIGHT WITH JUST SOME DIURNALLY DRIVEN SHOWERS/ISOLATED
THUNDERSTORMS MONDAY MAINLY ALONG AND INLAND OF ANY LAKE
BREEZES...WITH THE BEST CHANCES ACROSS THE SOUTHERN TIER.

THE SURFACE LOW WILL WEAKEN AND ELONGATE AS IT CROSSES SOUTHERN
ONTARIO ON SUNDAY. ACTUAL BOUNDARY ASSOCIATED WITH THIS SYSTEM LOOKS
AS THOUGH IT WILL NEVER ACTUALLY MAKE IT INTO NEW YORK
STATE...BECOMING NEARLY STATIONARY ACROSS SOUTHERN QUEBEC AS THE
AFOREMENTIONED SURFACE LOW RIDES EAST ALONG IT. HOWEVER A WEAK
SURFACE TROUGH OUT AHEAD OF THIS BOUNDARY WILL PUSH THROUGH THE
FORECAST AREA BY EARLY AFTERNOON...HELPING TO ENHANCE
SHOWER/THUNDERSTORM CHANCES ESPECIALLY DURING THE FIRST HALF OF THE
DAY. PWATS WILL RUN BETWEEN 1.75"-2" AHEAD OF THE SURFACE
BOUNDARY...THEN DROP OFF QUITE A BIT BEHIND THE TROUGH WITH PWATS
LOWERING DOWN TO AROUND 1.25" DURING THE AFTERNOON. MAIN SHORTWAVE
ENERGY AND BEST FORCING ALOFT WILL ALSO REMAIN NORTH OF NEW YORK
STATE. SO EVEN THOUGH PLENTY OF MOISTURE WILL BE IN PLACE DURING THE
FIRST HALF OF THE DAY...THE COMBINATION OF THE SURFACE TROUGH
PASSING THROUGH THE FORECAST AREA BY EARLY AFTERNOON PRIOR TO PEAK
HEATING AND THE LACK OF GOOD UPPER LEVEL SUPPORT...AM NOT EXPECTING
ANY WIDESPREAD HEAVY RAIN PRODUCING THUNDERSTORMS...ALTHOUGH A FEW
ISOLATED HEAVY DOWNPOURS CANNOT BE RULED OUT. IN FACT...IT LOOKS AS
THOUGH A LAKE SHADOW MAY FORM OVER THE NIAGARA FRONTIER NORTHEAST OF
LAKE ERIE DURING THE AFTERNOON THANKS TO STRONG SOUTHWEST FLOW
BLOWING IN OFF THE NORTHEAST END OF THE LAKE. A SIMILAR TREND MAY BE
SEEN NORTHEAST OF LAKE ONTARIO A BIT LATER IN THE DAY AS WELL. THERE
WILL NOT BE MUCH COOLING ASSOCIATED WITH THE PASSAGE OF THE SURFACE
TROUGH AS HIGHS ON SUNDAY WILL STILL BE IN THE UPPER 70S TO LOWER
80S.

EXPECT MAINLY DRY CONDITIONS SUNDAY NIGHT WITH WEAK RIDGING ALOFT
AND AT THE SURFACE. TEMPERATURES SUNDAY NIGHT WILL REMAIN ON THE
WARM SIDE WITH LOWS MAINLY IN THE LOW TO MID 60S.

A WARM AND STICKY AIRMASS WILL REMAIN ACROSS THE REGION ON MONDAY
WITH CHANCES FOR SHOWERS AN THUNDERSTORMS MAINLY IN THE AFTERNOON
AND EVENING. STEEPENING LOW LEVEL LAPSE RATES AND CAPES NEARING OR
EVEN BETTERING 1000 J/KG BY LATER IN THE DAY WILL HELP TO INCREASE
INSTABILITY. BEST CHANCES FOR CONVECTION WILL BE ALONG ANY LAKE
BREEZES AND THE HIGHER TERRAIN ACROSS THE SOUTHERN TIER.
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
ISOLATED STORMS MAY CONTINUE LATE INTO THE EVENING...ESPECIALLY
ACROSS THE SOUTHERN TIER. AT THE SAME TIME A COLD FRONT OVER THE
UPPER GREAT LAKES WILL BE ADVANCING TOWARD THE REGION AND BE LOCATED
JUST WEST OF NEW YORK STATE BY EARLY TUESDAY MORNING. THAT
SAID...THE NIGHT LOOKS TO REMAIN DRY FOR THE MOST PART...WITH PRECIP
CHANCES STARTING TO INCREASE A BIT ACROSS WESTERN NEW YORK TOWARD
EARLY TUESDAY MORNING. ANOTHER MILD NIGHT CAN BE EXPECTED WITH LOWS
IN THE MID TO UPPER 60S FOR MOST LOCATIONS THANKS TO DEEP SOUTHERLY
FLOW JUST AHEAD OF THE APPROACHING COLD FRONT.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
A PACIFIC BASED COLD FRONT WILL CROSS THE REGION ON TUESDAY. EXPECT
SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF THE FRONT.
BOTH THE GFS AND THE ECMWF BRING THE LEADING EDGE OF THE
PRECIPITATION INTO FAR WESTERN NEW YORK TUESDAY MORNING...HOWEVER
THE ECMWF DEVELOPS A WEAK AREA OF LOW PRESSURE ALONG THE FRONT OVER
THE OHIO VALLEY. THIS LOW THEN RIDES NORTHEAST ALONG THE FRONT AS IT
PRESSES ACROSS NEW YORK STATE. THIS WOULD SLOW THE FRONT DOWN A
BIT...WHILE ALSO POTENTIALLY GIVING THE AREA A BIT MORE IN THE WAY
OF RAINFALL. ALTHOUGH THE MAIN RAIN CHANCES WILL BE TUESDAY...WILL
HANG ONTO CHANCE POPS THROUGH THE OVERNIGHT WITH CHANCES LESSENING
FROM WEST TO EAST DUE TO THE POTENTIAL OF THE SYSTEM SLOWING DOWN A
BIT AS SHOWN BY THE ECMWF. PACIFIC BASED AIR BEHIND THIS FRONT WILL
ONLY DROP TEMPERATURES A HANDFUL OF DEGREES WITH HIGHS IN THE MIDDLE
TO UPPER 70S AND LOWS IN THE UPPER 50S TO LOWER 60S.

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.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
VFR WILL PREVAIL FOR MOST OF THE 12Z TAF CYCLE. A FEW PATCHES OF
MID TO HIGH CLOUDS WILL BRUSH THE REGION THROUGH EARLY
AFTERNOON...WITH PERHAPS A STRAY SHOWER OR THUNDERSTORM AT JHW-
IAG WITH A WARM FRONT. A SCT-BKN CUMULUS FIELD WILL ALSO DEVELOP
DURING THE AFTERNOON ACROSS THE SOUTHERN TIER AND WESTERN FINGER
LAKES WITH CIGS IN THE 035-050 RANGE. AN ISOLATED SHOWER OR
THUNDERSTORM IS POSSIBLE IN THIS SAME AREA DURING THE MID TO LATE
AFTERNOON BUT COVERAGE SHOULD REMAIN SPARSE. ELSEWHERE EXPECT DRY
CONDITIONS TO LAST THROUGH AT LEAST EARLY EVENING.

TONIGHT THE APPROACH OF A MID LEVEL DISTURBANCE AND SURFACE TROUGH
WILL BRING INCREASING CHANCES OF SHOWERS AND SCATTERED
THUNDERSTORMS. CIGS/VSBY WILL INITIALLY BE MAINLY VFR...WITH MVFR
BECOMING MORE LIKELY LATE TONIGHT AS THE LOW LEVELS BEGIN TO
SATURATE. SOME IFR MAY DEVELOP TOWARDS 12Z ACROSS HIGHER TERRAIN.
ANY OF THE HEAVIER SHOWERS AND STORMS MAY ALSO PRODUCE BRIEF/LOCAL
IFR.

OUTLOOK...
SUNDAY...MVFR IN THE MORNING WITH SHOWERS AND THUNDERSTORMS LIKELY.
IFR POSSIBLE ACROSS HIGHER TERRAIN. BECOMING MAINLY VFR IN THE
AFTERNOON.
MONDAY AND TUESDAY...VFR/MVFR IN SCATTERED SHOWERS AND THUNDERSTORMS.
WEDNESDAY...VFR.

&&

.MARINE...
HIGH PRESSURE WILL DRIFT OFF THE NEW ENGLAND COAST TODAY WITH
SOUTHERLY BREEZES IN ITS WAKE. THE SOUTHERLY WINDS WILL BE MODERATE
THIS MORNING AT THE NORTHEAST CORNER OF LAKE ONTARIO WITH CHOPPY
WAVE CONDITIONS FROM GALLOO ISLAND TO CAPE VINCENT. THESE WINDS AND
WAVES SHOULD DIMINISH SOMEWHAT FOR THE AFTERNOON. A WEAK AREA OF LOW
PRESSURE WILL TRACK FROM LAKE HURON LATE TONIGHT ACROSS SOUTHERN
QUEBEC ON SUNDAY. THIS WILL BRING INCREASING SOUTHWEST WINDS ON LAKE
ERIE AND THE NORTHEAST END OF LAKE ONTARIO...WITH WINDS AND WAVES
POSSIBLY APPROACHING SMALL CRAFT ADVISORY CRITERIA LATE TONIGHT AND
SUNDAY MORNING. GIVEN THE MARGINAL NATURE OF THIS...WILL HOLD OFF ON
ANY SCA HEADLINES FOR NOW.

&&

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

&&

$$

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







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