Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 211503
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1103 AM EDT THU AUG 21 2014

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL BRING CONTINUED CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING...ESPECIALLY ACROSS
THE EASTERN LAKE ONTARIO REGION WHERE A STATIONARY 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/...
LATE THIS MORNING WATER VAPOR IMAGERY DISPLAYS A CLOSED UPPER LEVEL
LOW NEAR LAKE HURON/GEORGIAN BAY. A WEAK SURFACE LOW IS REFLECTED AT
THE SURFACE BETWEEN GEORGIAN BAY AND THE EASTERN GREAT LAKES. AN ILL
DEFINED STATIONARY FRONT LIES ACROSS WESTERN AND NORTH CENTRAL NEW
YORK.

A MOISTURE RICH BOUNDARY LAYER...COMBINED WITH DAYTIME HEATING IS
PRODUCING A THIN LAYER OF DIURNAL CUMULUS CLOUDS ACROSS WESTERN NEW
YORK LATE THIS MORNING. EXPECT THESE TO LIFT SOME AND SCATTER OUT AS
WE CONTINUE TO HEAT UP THIS AFTERNOON...WITH MORE CLOUDS HANGING ON
INLAND FROM THE LAKES.

REGIONAL RADARS SHOWING WHAT IS LEFT OF LINE OF SHOWERS MOVING EAST
THROUGH THE EASTERN LAKE ONTARIO REGION LATE THIS MORNING. THIS
ACTIVITY.

FOR THE REST OF 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
STATIONARY 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...ALTHOUGH MANY AREAS WEST OF
THE FINGER LAKES REGION WILL LIKELY REMAIN RAIN FREE TODAY.

LATER THIS AFTERNOON A WEDGE OF DRIER AIR IN THE 850-500 HPA LAYER
WILL LIKELY DIMINISH ANY CONVECTIVE SHOWER CHANCES ACROSS FAR WNY.
THEN AS THIS DRIER LAYER PUSHES EASTWARD IN COMBINATION WITH 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. 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 /15Z THURSDAY THROUGH MONDAY/...
AT 15Z A COMBINATION OF MVFR/VFR FLIGHT CONDITIONS WERE FOUND ACROSS
THE REGION. A MOISTURE RICH BOUNDARY LAYER...COMBINED WITH SOME
DAYTIME HEATING IS ALREADY PRODUCING A THIN LAYER OF MAINLY MVFR
CIGS ACROSS WESTERN NEW YORK LATE THIS MORNING. EXPECT THESE TO LIFT
SOME AND SCATTER OUT AS WE CONTINUE TO HEAT UP THIS AFTERNOON...WITH
MORE CLOUDS HANGING ON INLAND FROM THE LAKES.

SCATTERED SHOWERS WILL THEN BE POSSIBLE THROUGH THIS AFTERNOON DUE
TO PLENTY OF AVAILABLE LOW LEVEL MOISTURE IN COMBINATION WITH
DAYTIME HEATING. A THUNDERSTORM WILL ALSO BE POSSIBLE ACROSS THE
NORTH COUNTRY. WITH THE ACTIVITY BEING SCATTERED IN NATURE WILL
CONTINUE WITH VCSH FOR ALL TAF SITES...WITH SHOWER ACTIVITY MOST
LIKELY ACROSS THE NORTHERN FINGER LAKES REGION AND NORTH COUNTRY.

MUCH OF THE PRECIPITATION WILL COME TO AN END OVER THE LAST 12 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 ARE LIKELY WITH MVFR/IFR FLIGHT CONDITIONS
DEVELOPING ACROSS ALL TAF SITES. THE EXTENT OF MVFR/IFR VISIBILITY
VERSUS MVFR/IFR CIGS WILL BE DEPENDENT ON HOW MUCH CLEARING IS SEEN
EARLIER IN THE OVERNIGHT.

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 THIS AFTERNOON...AND THEN DISSIPATE TONIGHT OVER THE LOWER
LAKES REGION. OCCASIONAL SHOWERS AND A FEW THUNDERSTORMS WILL BE
POSSIBLE THROUGH THIS 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...JM/THOMAS
NEAR TERM...JM/THOMAS
SHORT TERM...APFFEL
LONG TERM...APFFEL/RSH
AVIATION...JM/THOMAS
MARINE...JM/THOMAS







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