Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 210835
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
435 AM EDT THU AUG 21 2014

.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL BRING CONTINUED CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING...ESPECIALLY ACROSS
THE EASTERN LAKE ONTARIO REGION WHERE A WARM FRONT LIES. A FEW
SHOWERS OR A THUNDERSTORM WILL LINGER INTO FRIDAY AND SATURDAY...BUT
MUCH OF THE TIME WILL BE RAIN FREE WITH SEASONABLE TEMPERATURES. AN
AREA OF HIGH PRESSURE WILL BRING DRY CONDITIONS ON SUNDAY WITH
MOSTLY SUNNY SKIES.

&&

.NEAR TERM /THROUGH TONIGHT/...
EARLY THIS MORNING WATER VAPOR IMAGERY DISPLAYS A CLOSED UPPER LEVEL
LOW OVER LAKE HURON. A WEAK SURFACE LOW IS REFLECTED AT THE SURFACE
BETWEEN GEORGIAN BAY AND THE EASTERN GREAT LAKES. AN ILL DEFINED
WARM FRONT LIES ACROSS WESTERN AND NORTH CENTRAL NEW YORK.

WITH LIGHT SURFACE WINDS AND A MOISTURE RICH BOUNDARY LAYER SOME
PATCHY AREAS OF FOG ARE FORMING ACROSS THE SOUTHERN TIER...AND
THROUGH THE FINGER LAKES REGION TO THE NORTH COUNTRY...GENERALLY IN
AREAS WHERE RAIN FELL THE PRECEDING DAY. THIS PATCHY FOG WILL
DISSIPATE EARLY MORNING WITH THE RISING SUN/MIXING HEIGHTS.

FOR TODAY IN THE PRESENCE OF THE UPPER LEVEL LOW...AND BOUNDARY
LAYER CONVERGENT CIRCULATION AROUND THE SURFACE LOW SCATTERED
SHOWERS AND DAYTIME INSTABILITY THUNDERSTORMS WILL FORM. ACTIVITY
WILL BE MOST PROMINENT ACROSS THE NORTHERN FINGER LAKES AND EASTERN
LAKE ONTARIO REGION WHICH WILL LIE CLOSER TO THE WEAK WARM FRONT AS
WELL AS DEEPER MOISTURE. ACROSS WNY SCATTERED ACTIVITY WILL BE MOST
LIKELY THROUGH THE AFTERNOON HOURS WHEN WEAK SURFACE INSTABILITY
WILL BE GREATEST.

LATER THIS AFTERNOON A WEDGE OF DRIER AIR IN THE 850-500 HPA LAYER
WILL DIMINISH CONVECTIVE SHOWER CHANCES ACROSS FAR WNY. THEN AS THIS
DRIER LAYER PUSHES EASTWARD IN COMBINATION OF THE LOSS OF DAYTIME
INSTABILITY AND WEAKENING OF THE UPPER LEVEL LOW...SHOWERS AND ANY
REMAINING THUNDERSTORMS WILL END FROM WEST TO EAST THROUGH THE EARLY
OVERNIGHT HOURS.

AS THE SURFACE LOW WEAKENS TONIGHT OVER THE REGION AND SURFACE WINDS
GO LIGHT AND VARIABLE...LINGERING LOW LEVEL MOISTURE WILL BRING
PATCHY FOG ACROSS THE REGION. FOG AND LOW CLOUDS WILL LIKELY BE
THICKEST ACROSS THE VALLEYS AND HILLS OF SW NYS.

AIR TEMPERATURES WILL BE SEASONABLE TODAY WITH AFTERNOON
TEMPERATURES SOUTH OF LAKE ONTARIO SIMILAR TO YESTERDAY...WITH
HIGHS IN THE MID 70S TO AROUND 80. THE COOLEST 24-HR CHANGE TO THE
AFTERNOON TEMPERATURES WILL BE ACROSS THE NORTH COUNTRY WHERE TODAY WILL
START CLOUDY AS OPPOSED TO YESTERDAY WHEN SOME SUNSHINE STARTED THE
DAY. TONIGHT LOWS WILL RANGE THROUGH THE LOW TO MID 60S WITH A
CONTINUED MUGGINESS FEEL TO THE AIR...ESPECIALLY IN AREAS WHERE FOG
FORMS.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
THE PERIOD WILL START OFF WITH AN UPPER LEVEL TROUGH ACROSS NEW
ENGLAND...BUT THIS WILL GRADUALLY BREAK DOWN AS AN UPPER LEVEL RIDGE
DEVELOPS. THERE WILL BE MODEST INSTABILITY ON FRIDAY...NAM FORECAST
SOUNDINGS SHOWING THIN AND NARROW CAPE OF AROUND 500 J/KG. IT IS
DIFFICULT TO FIND ANY CLEARLY DEFINED SYNOPTIC TRIGGERS FOR
CONVECTION...BUT THERE DOES APPEAR TO BE SUBTLE AREA WITH SURFACE
CONVERGENCE EAST OF GENESEE VALLEY. NAM/SREF/RGEM/GFS CONSENSUS QPF
ALSO KEYS ON THIS REGION...BUT EXPECT COVERAGE TO BE SPARSE
SUPPORTING JUST CHANCE POPS. OTHERWISE...A DEVELOPING NE FLOW OFF
LAKE ONTARIO MAY HELP SHADOW THE NIAGARA FRONTIER FRIDAY AFTERNOON.
AREAL COVERAGE SHOULD DIMINISH WITH THE LOSS OF DAYTIME
HEATING...BUT A FEW SHOWERS MAY LINGER THROUGH FRIDAY NIGHT.
STRONGER CELLS WILL PROBABLY HAVE LIGHTNING...BUT THUNDERSTORMS
SHOULD BE FAIRLY SPARSE IN COVERAGE.

THE UPPER LEVEL RIDGE WILL BUILD INTO THE NORTH COUNTRY ON SATURDAY
BEFORE SPREADING ACROSS THE ENTIRE REGION ON SUNDAY. THERE MAY BE A
FEW DIURNAL SHOWERS SATURDAY...BUT THESE SHOULD END QUICKLY SATURDAY
NIGHT WITH DRY WEATHER FOR THE REMAINDER OF THE WEEKEND.
TEMPERATURES WILL BE RATHER SEASONABLE...WITH DAYTIME HIGHS
AVERAGING IN THE MID TO UPPER 70S FRIDAY AND SATURDAY. SUNDAY SHOULD
BE A TAD WARMER WITH A BIT MORE SUNSHINE ALLOWING A FEW SPOTS TO
REACH 80 DEGREES.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPPER LEVEL RIDGING WILL SUPPORT SURFACE HIGH PRESSURE WHICH SHOULD
INFLUENCE OUR WEATHER WELL INTO NEXT WEEK. 00Z RUNS OF THE
GFS/ECMWF/GGEM CONTINUE TO KEEP WESTERN NEW YORK DRY THROUGH AT
LEAST MONDAY NIGHT. THE RIDGE SHOULD START TO BREAK DOWN BY
MID-WEEK...BUT EVEN AS IT DOES THERE IS ONLY A SMALL CHANCE OF
SHOWERS THROUGH MID-WEEK. THIS SHOULD RESULT IN A NICE STRETCH OF
WEATHER FOR OUR REGION...WITH MAINLY DRY WEATHER AND AMPLE SUNSHINE.
MEANWHILE TEMPERATURES SHOULD BE A BIT ABOVE NORMAL...WITH HIGHS IN
THE UPPER 70S TO LOWER 80S.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AT 06Z MAINLY VFR FLIGHT CONDITIONS WERE FOUND ACROSS THE
REGION...THOUGH A MOIST AIRMASS AND LIGHT WINDS WILL LIKELY BRING
IFR/MVFR FLIGHT CONDITIONS. THESE CONDITIONS WILL BE MOST PROMINENT
ACROSS THE SOUTHERN TIER AND ALSO THE EASTERN LAKE ONTARIO REGION
WHERE RAIN FELL WEDNESDAY AND WEDNESDAY EVENING. ELSEWHERE ACROSS
THE NORTHERN WNY AREAS EXPECT MAINLY VFR OR HIGH END MVFR CIGS
THROUGH THE EARLY MORNING.

ALL AREAS SHOULD RETURN TO VFR THROUGH THE DAYLIGHT HOURS THURSDAY.
SCATTERED SHOWERS WILL BE POSSIBLE IN THE PEAK OF DAYTIME HEATING
WITH A THUNDERSTORM ALSO POSSIBLE ACROSS THE NORTH COUNTRY.

MUCH OF THE PRECIPITATION WILL COME TO AN END OVER THE LAST 6 HOURS
OF THE TAF CYCLE...WITH THE REGION BECOMING MOSTLY DRY THROUGH THE
OVERNIGHT TIME PERIOD. AS WINDS GO LIGHT AND VARIABLE OVERNIGHT SOME
PATCHY TO AREAS OF FOG IS LIKELY WITH MVFR/IFR FLIGHT CONDITIONS
DEVELOPING ACROSS ALL TAF SITES.

OUTLOOK...
FRIDAY AND SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SUNDAY AND MONDAY...MAINLY VFR.

&&

.MARINE...
BROAD LOW PRESSURE OVER LAKE HURON WILL DRIFT EASTWARD TOWARDS LAKE
ONTARIO TODAY...AND THEN DISSIPATE THURSDAY NIGHT OVER THE LOWER
LAKES REGION. OCCASIONAL SHOWERS AND A FEW THUNDERSTORMS WILL BE
POSSIBLE THROUGH THURSDAY EVENING AS THIS LOW TRACKS
EASTWARD...OTHERWISE A RELATIVELY FLAT PRESSURE GRADIENT WILL REMAIN
IN PLACE AND PROMOTE MINIMAL WINDS AND WAVES RIGHT THROUGH THE END
OF THE WEEK.

&&

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

&&

$$

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






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