Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 191428
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1028 AM EDT TUE AUG 19 2014

.SYNOPSIS...
HIGH PRESSURE DRAPED FROM QUEBEC PROVINCE TO EASTERN NEW YORK WILL
SETTLE ACROSS NEW ENGLAND TODAY. WHILE THIS WILL CONTINUE TO PROVIDE
THE VAST MAJORITY OF WESTERN AND NORTH CENTRAL NEW YORK WITH DRY
WEATHER...INTERIOR PORTIONS OF THE SOUTHERN TIER AND FINGER LAKES
COULD SEE A SHOWER OR THUNDERSTORM THIS AFTERNOON AS MOISTURE BEGINS
STREAMING NORTHWARD INTO OUR REGION. MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS ARE THEN EXPECTED WEDNESDAY AND THURSDAY AS A WARM
FRONT LIFTS INTO OUR REGION FROM THE OHIO VALLEY...THEN STALLS OUT.

&&

.NEAR TERM /THROUGH TONIGHT/...
SATELLITE IMAGERY LATE THIS MORNING SHOWING A PLUME OF LOW LEVEL
MOISTURE ADVECTING NORTHWARD OUT OF PA AND INTO THE GENESEE VALLEY
AND WESTERN FINGER LAKES. THIS IS PRODUCING SOME ENHANCED CLOUD
COVER IN THIS AREA...WITH A FEW LOCATIONS SEEING CLOUDY SKIES FOR AN
HOUR OR TWO THROUGH MIDDAY. WITH DAYTIME HEATING THIS LOW LEVEL
MOISTURE FIELD SHOULD MIX OUT TO SOME EXTENT...WITH A MIX OF SUN AND
CLOUDS EXPECTED FOR THE AFTERNOON IN THE FINGER LAKES. UPSTREAM A
BAND OF MID LEVEL CLOUD OVER SOUTHWEST ONTARIO WILL MOVE INTO THE
FAR WESTERN END OF THE STATE BY MID AFTERNOON WITH SOME INCREASE IN
CLOUD COVER.

THROUGH THE NEAR TERM PERIOD...ELONGATED HIGH PRESSURE EXTENDING
FROM QUEBEC PROVINCE TO EASTERN NEW YORK WILL DRIFT OUT ACROSS NEW
ENGLAND...WHILE THE NEXT MID LEVEL TROUGH AND ATTENDANT BROAD
SURFACE LOW SLIDES ACROSS THE WESTERN AND CENTRAL GREAT LAKES...WITH
THIS LATTER FEATURE SWINGING ITS WARM FRONT TOWARD OUR AREA FROM
THE OHIO VALLEY TONIGHT.

FOR THE VAST MAJORITY OF THE REGION...THIS WILL RESULT ONE MORE DRY
DAY TODAY WITH THE LATTER SYSTEM REMAINING TOO FAR TO OUR WEST TO
HAVE ANY NOTABLE IMPACT ON OUR WEATHER. THE ONE POSSIBLE EXCEPTION
TO THIS WILL BE ACROSS INTERIOR SECTIONS OF THE SOUTHERN TIER AND
FINGER LAKES...WHERE THE COMBINATION OF SLOWLY INCREASING
MOISTURE...DIURNAL HEATING...AND A DEVELOPING BROAD AREA OF LOW
LEVEL CONVERGENCE MAY BE ENOUGH TO POP A FEW SCATTERED SHOWERS AND
THUNDERSTORMS ONCE AN INHIBITING MID LEVEL CAP ERODES AWAY THIS
AFTERNOON. OTHERWISE...EXPECT A WARMER DAY WITH TEMPERATURES FINALLY
RETURNING TO RIGHT AROUND AVERAGE OWING TO SOME MODEST WARMING
ALOFT. MOST PLACES SHOULD SEE HIGHS REACHING THE UPPER 70S WITH A
FEW LOWER 80-DEGREE READINGS POSSIBLE IN OUR NORMALLY WARMER
INTERIOR LOCATIONS...THOUGH IT WILL BE A LITTLE COOLER ACROSS THE
HIGHER TERRAIN...AS WELL AS ALONG AND INLAND FROM THE SOUTHERN LAKE
ONTARIO SHORELINE DUE TO A DEVELOPING NORTHEASTERLY LOW LEVEL FLOW
OFF THE COOLER LAKE WATERS.

TONIGHT...ANY SCATTERED CONVECTION THAT DEVELOPS ACROSS INTERIOR
SECTIONS SHOULD GRADUALLY SLIDE EASTWARD AND DISSIPATE DURING THE
EVENING WITH THE LOSS OF HEATING. OTHERWISE...EXPECT INITIALLY QUIET
CONDITIONS TO GIVE WAY TO INCREASING CLOUDS FROM SOUTHWEST TO
NORTHEAST WITH THE APPROACH OF THE WARM FRONT...WITH THIS LATTER
FEATURE EVENTUALLY BRINGING THE CHANCE FOR SOME SHOWERS TO FAR
WESTERN NEW YORK OVERNIGHT. WITH THE INCREASING CLOUD COVER AND A
WARMER AND SOMEWHAT MORE HUMID AIRMASS IN PLACE...TEMPERATURES WILL
BE CONSIDERABLY MILDER THAN THOSE OF THE PREVIOUS FEW NIGHTS...WITH
OVERNIGHT LOWS RANGING FROM THE MID TO UPPER 50S ACROSS THE NORTH
COUNTRY TO THE LOWER AND MID 60S ELSEWHERE.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
THIS WILL CERTAINLY BE AN UNSETTLED PERIOD...ESPECIALLY EARLY ON AS
SEVERAL INGREDIENTS WILL COME INTO PLACE TO GENERATE SOME WIDESPREAD
RAINS. THIS RAINFALL COULD BE LOCALLY SIGNIFICANT. ALONG WITH THE
WET WEATHER...IT WILL FINALLY FEEL MORE LIKE SUMMER AS TEMPERATURES
WILL AVERAGE ABOVE NORMAL WITH MODERATELY HIGH HUMIDITY.

THE MAIN DRIVING FORCE FOR THE INCLEMENT WEATHER WILL BE A BROAD
UPPER LEVEL LOW...THAT INITIALLY ON WEDNESDAY WILL BE SITUATED OVER
THE UPPER GREAT LAKES. A DIVERGENT UPPER LEVEL FLOW FOUND DOWNWIND
OF THIS FEATURE WILL COUPLE WITH SOME WEAK WARM ADVECTION TO PRODUCE
GENERAL ASCENT ACROSS ALL OF OUR FORECAST AREA...WITH AT LEAST ONE
GUIDANCE PACKAGE SUGGESTING ADDITIONAL LIFT FROM A COUPLED H25 JET.
THIS LIFT WILL BE FOUND WITHIN A VERY MOIST (PWAT APPROACHING 2")
AND CONDITIONALLY UNSTABLE AIRMASS...AND WITH SHORT MBE VECTORS ALSO
BEING ADVERTISED...THE POTENTIAL WILL BE IN PLACE FOR SOME LOCALLY
HEAVY RAIN. THE GREATEST RISK FOR THE MORE SIGNIFICANT RAIN WILL
COME IN ANY SLOW MOVING THUNDERSTORM THAT DEVELOPS...AS TALL THIN
CAPE PROFILES AND A `WARM` CONVECTIVE CLOUD DEPTH OF 10-15K FT
(FAVORABLE MICROPHYSICS FOR MORE EFFICIENT RAIN PRODUCTION) ARE
ANTICIPATED.

ALL OF THAT BEING SAID...AM NOT SURE IF THE MATURE CYCLONE OVER THE
UPPER GREAT LAKES WILL PUSH A STRONG ENOUGH OCCLUSION ACROSS OUR
REGION TO FOCUS THE EXPECTED PCPN. WILL INCREASE POPS TO CATEGORICAL
BUT ONLY FORECAST BASIN AVERAGE QPF OF A QUARTER TO A HALF INCH ON
WEDNESDAY BECAUSE OF THIS UNCERTAINTY. THE POTENTIAL WILL BE THERE
THOUGH FOR LOCALLY HIGHER AMOUNTS (>1 INCH). THIS RISK WILL BE
COVERED IN THE HAZARDOUS WEATHER OUTLOOK (HWO). WEDNESDAY WILL BE
WARM AND HUMID (AS ONE WOULD EXPECT WITH PWAT`S NR 2") WITH MAX
TEMPS GENERALLY IN THE MID-UPPER 70S IN THE WEST AND NR 80 EAST OF
ROC.

THE UPPER LEVEL LOW WILL OPEN UP INTO A BROAD LONGWAVE TROUGH OVER
THE LOWER GREAT LAKES WEDNESDAY NIGHT. WHILE THE LIFT FROM THE
DIVERGENT UL FLOW AND WARM ADVECTION WILL PUSH OFF TO THE EAST...
THERE WILL STILL BE ENOUGH LIFT UNDER THE BASE OF THE H5 TROUGH TO
PRODUCE SOME SHOWERS...WITH THE MOST WIDESPREAD ACTIVITY PUSHING
EAST OF ROCHESTER IN THE VCNTY OF THE SLOW MOVING SFC OCCLUSION.
WILL TIE THE POTENTIAL FOR HEAVY RAIN TO THIS FOCUSING BOUNDARY
WHILE RAISING POPS TO CATEGORICAL (HIGH CHC SW CORNER OF STATE) FOR
THE BULK OF THE FORECAST AREA. QPF WILL BE IN THE VCNTY OF 0.2 TO
0.4" WITH THE HIGHER AMOUNTS FOUND EAST OF THE GENESEE VALLEY. FOR
THE SECOND NIGHT IN A ROW...MERCURY READINGS WILL ONLY DROP INTO THE
LOW TO MID 60S.

ON THURSDAY...THE BASE OF THE H5 TROUGH WILL PUSH ACROSS THE
FORECAST AREA TO NEW ENGLAND ALONG WITH THE DEEPEST MOISTURE FIELD.
A HUMID...CONDITIONALLY UNSTABLE AIRMASS WILL REMAIN IN PLACE THOUGH
SO WILL CONTINUE TO CARRY LIKELY POPS FOR SHOWERS AND POSSIBLE
TSTORMS.

AS THE TROUGH MOVES EAST THURSDAY NIGHT...RIDGING OVER THE MID WEST
AND UPPER GREAT LAKES WILL BUILD TO THE EAST. THIS WILL ENCOURAGE
THE SHOWER ACTIVITY TO TAPER OFF FROM WEST TO EAST WITH ONLY CHC
POPS REMAINING IN PLACE.

FOR FRIDAY AND FRIDAY NIGHT...THE RIDGING WILL AMPLIFY TO OUR WEST
WITH BOTH THE GFS AND ECMWF SUGGESTING THAT SOME SUBTLE SHORTWAVES
WILL DROP SOUTHEAST ALONG A STRENGTHENING WARM FRONT. DEPENDING ON
THE TIMING OF THESE IMPULSES...THERE COULD BE SOME SHOWERS OVER THE
WESTERN COUNTIES. WILL KEEP LOW CHC POPS IN PLACE FOR FRIDAY WITH
SLGT CHC FRIDAY NIGHT UNTIL ADDITIONAL GUIDANCE ADDS SUPPORT TO THIS
SCENARIO.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
TEMPERATURES WILL AVERAGE A LITTLE ABOVE NORMAL DURING THIS PERIOD
AS AN AMPLIFYING RIDGE OVER THE UPPER GREAT LAKES IS FORECAST TO
EVENTUALLY `FOLD OVER` ACROSS NEW ENGLAND AND THE ST LAWRENCE
VALLEY. UNDER THIS H5 RIDGE...A WEAK DISTURBANCE WILL TRY TO PUSH A
WARM FRONT EASTWARD ACROSS THE LOWER GREAT LAKES. THIS WILL KEEP THE
POTENTIAL FOR SHOWERS...AT LEAST FOR THE WESTERN COUNTIES...IN PLACE
FOR MUCH OF THE PERIOD.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THROUGH THE COURSE OF THE TAF PERIOD...HIGH PRESSURE DRAPED FROM
QUEBEC INTO CENTRAL NEW YORK WILL SLIDE EAST AND OUT ACROSS NEW
ENGLAND...WHILE BROAD LOW PRESSURE DRIFTS ACROSS THE WESTERN/CENTRAL
GREAT LAKES AND PUSHES A WARM FRONT TOWARD OUR REGION FROM THE OHIO
VALLEY.

FOR THE MOST PART...THIS WILL RESULT IN CONTINUED DRY VFR WEATHER
ACROSS OUR REGION WITH JUST A GENERAL INCREASE IN CLOUD COVER TODAY
AND TONIGHT...THOUGH THERE WILL BE A FEW EXCEPTIONS. THESE ARE AS
FOLLOWS...

1. ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER AND FINGER
LAKES...THE COMBINATION OF DAYTIME HEATING AND SLOWLY INCREASING
MOISTURE MAY LEAD TO THE DEVELOPMENT OF A FEW SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND EARLY THIS EVENING...WHICH COULD
PRODUCE VERY BRIEF/LOCALIZED MVFR RESTRICTIONS AWAY FROM THE TAF
SITES.

2. SOME ADDITIONAL SCATTERED SHOWERS WILL ALSO BE POSSIBLE TONIGHT
AS THE WARM FRONT APPROACHES OUR REGION. THESE COULD PRODUCE SOME
ADDITIONAL SPOTTY REDUCTIONS TO MVFR...WITH GENERAL VFR CONDITIONS
OTHERWISE PREVAILING.

OUTLOOK...
WEDNESDAY AND THURSDAY...OCCASIONAL SHOWERS AND THUNDERSTORMS WITH
ATTENDANT LOCALIZED REDUCTIONS TO IFR/MVFR.
FRIDAY AND SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS.

&&

.MARINE...
HIGH PRESSURE DRAPED FROM QUEBEC PROVINCE TO EASTERN NEW YORK WILL
SETTLE ACROSS NEW ENGLAND TODAY. A WARM FRONTAL BOUNDARY WILL THEN
LIFT INTO THE LOWER LAKES REGION ON WEDNESDAY AND LINGER THROUGH
THURSDAY...BEFORE GETTING SHUNTED SOUTHWARD AGAIN ON FRIDAY.
WHILE THE WARM FRONT WILL BRING OCCASIONAL SHOWERS AND THUNDERSTORMS
TO THE REGION WEDNESDAY AND THURSDAY...WINDS AND WAVES ARE EXPECTED
TO REMAIN BELOW ADVISORY LEVELS THROUGH THE END OF THE WORK WEEK.

&&

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

&&

$$

SYNOPSIS...JJR
NEAR TERM...HITCHCOCK/JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...HITCHCOCK/JJR
MARINE...JJR





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