Area Forecast Discussion
Issued by NWS

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FXUS61 KPBZ 030116
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
916 PM EDT SUN AUG 2 2015

.SYNOPSIS...
A COLD FRONT WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TO START
THE WORK WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
CUMULUS HAS ENTIRELY FADED AS ABUNDANT DRY AIR IN THE RATHER
WELL-MIXED COLUMN QUICKLY ERODED ALL CLOUD COVER. WIND GUSTS
SHOULD DIMINISH A BIT AFTER SUNSET...HOWEVER AMPLE MOMENTUM AND A
STRENGTHENING PRESSURE GRADIENT ARE LIKELY TO KEEP SOUTHWESTERLY
WINDS UP OVERNIGHT. THIS WILL ALLOW FOR YET ANOTHER WARM NIGHT AS
THE BOUNDARY LAYER SEEMS LIKELY TO REMAIN MIXED...PARTICULARLY IN
THE NORTHERN AND WESTERN AREAS OF THE CWA. OTHERWISE...URBAN HEAT
ISLANDS WILL REMAIN STRONG...AND LOWS LOOK POISED TO BE LARGELY IN
THE 60S TO NEAR 70 IN THE URBAN AREA. FRIES

PREVIOUS DISCUSSION FOR MONDAY FOLLOWS...ATTENTION WILL THEN TURN
TO THE LOW PRESSURE SYSTEM CURRENTLY OVER WISCONSIN...WHICH IS
RESPONSIBLE FOR SEVERE WEATHER GOING ON THIS AFTERNOON ACROSS
WISCONSIN AND MICHIGAN. WHILE THE LOW MOVES EAST OVERNIGHT...THE
ASSOCIATED COLD FRONT WILL SLIDE TO THE SOUTHEAST...WITH SHOWERS
AND THUNDERSTORMS CONTINUING ALONG THE FRONT. WHILE PRECIPITATION
SHOULD PERSIST...HIGH RESOLUTION MODELS HAVE THE SHOWERS WANING AS
THE FRONT APPROACHES NORTHERN OHIO NEAR SUNRISE.

IF THIS PLAYS OUT...TIMING COULD LIMIT OVERALL POTENTIAL FOR SEVERE
WEATHER...WITH SOMEWHAT OF A LULL IN PRECIPITATION ALONG THE FRONT
AS IT PASSES OVER THE WESTERN HALF OF OUR FORECAST AREA IN THE
MORNING. EVENTUALLY SHOWERS AND STORMS SHOULD DEVELOP AGAIN IN THE
AFTERNOON WITH THE DIURNAL CYCLE ACROSS EASTERN PORTIONS OF THE
FORECAST AREA. MODELS CONTINUE TO DISAGREE ON AMOUNT OF
INSTABILITY THE ATMOSPHERE WILL HAVE TO WORK WITH...ALTHOUGH THERE
IS GOOD MODEL AGREEMENT FOR MODEST UNIDIRECTIONAL WIND SHEAR THAT
COULD HELP TO ORGANIZE STORMS. THE SPC DAY 2 AFTERNOON UPDATE
REMAINS UNCHANGED FROM EARLIER TODAY...LEAVING THE FORECAST AREA
UNDER A SLIGHT RISK FOR SEVERE WEATHER...WHICH IS ALREADY
HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK.

OVERNIGHT LOWS SHOULD REMAIN A BIT WARMER THAN LAST NIGHT
CONSIDERING WINDS WILL NOT GO CALM AS WELL AS HIGH CLOUDS MOVING
IN BEFORE THE FRONT. MONDAY HIGHS WILL BE A FEW DEGREES COOLER
THAN TODAY WITH THE ARRIVAL OF THE COLD FRONT.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE MONDAY EVENING AS
THE FRONT CLEARS THE REGION...WITH ONLY SOUTHEASTERN COUNTIES
KEEPING A CHANCE OF RAIN AFTER MIDNIGHT. COMPARED TO
YESTERDAY...MODELS NOW SHOW THE COLD FRONT MOVING FAR ENOUGH SOUTH
OF THE REGION TO KEEP SOUTHERN COUNTIES WITH A DRY FORECAST ON
TUESDAY. MEANWHILE...TO THE NORTH...AN UPPER LEVEL LOW WILL MAKE
SLOW PROGRESS TO THE EAST...PASSING FROM ONTARIO INTO QUEBEC. MODELS
HAVE ALSO COME INTO LINE KEEPING MOST PRECIPITATION WITH TUESDAYS
SHORTWAVE TO THE NORTH OF THE REGION...ALTHOUGH A COUPLE OF SHOWERS
COULD CLIP NORTHERN COUNTIES. AFTER A DRY TUESDAY NIGHT...LOW
PRESSURE FROM THE CENTRAL PLAINS WILL MOVE EAST ON WEDNESDAY.
TEMPERATURES WILL REMAIN AROUND SEASONAL NORMS THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THERE IS GOOD AGREEMENT IN THE LONG TERM FORECAST AS AN UPPER
TROUGH REMAINS PARKED OVER THE EASTERN US. SEVERAL WAVES RIDING
THROUGH THE UPPER FLOW WILL MAINTAIN THE CHANCE FOR SHOWERS AND
THUNDERSTORMS THROUGH THE PERIOD...WITH OVERALL BETTER CONSENSUS
BETWEEN THE GFS AND ECMWF THAN IN THE PREVIOUS DAYS RUNS. WITH THE
TROUGH PROGGED TO DEEPEN BY NEXT WEEKEND...EXPECT TEMPERATURES TO
TREND A FEW DEGREES COOLER THAN SEASONAL AVERAGES IN NORTHERLY FLOW.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
EXPECTING VFR CONDITIONS TO PREVAIL THROUGH THE NIGHT AND INTO
MONDAY...ALTHOUGH HIGH PRESSURE WILL BEGIN SLIPPING TO THE EAST AS
A COLD FRONT APPROACHES THE REGION. TIMING THE FRONT ACROSS THE
FORECAST AREA AROUND MIDDAY MONDAY...GIVING RISE TO SHOWER AND
THUNDERSTORM ACTIVITY ALONG AND AHEAD OF IT. ANY RESTRICTIONS
THROUGH THE TAF PERIOD WILL BE BREIF AND ASSOCIATED WITH THESE
SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY APPROACH SEVERE
CRITERIA WITH STRONG WIND BEING THE MAIN THREAT. OUTSIDE OF
THUNDERSTORMS...LIGHT SURFACE WINDS WILL INCREASE AGAIN FROM THE
SOUTHWEST MONDAY MORNING...WITH A WIND SHIFT EXPECTED TO THE WEST-
NORTHWEST AS THE FRONT PASSES.
TAX

OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...
THE NEXT CHANCE FOR RESTRICTIONS IS EXPECTED WITH A THURSDAY
UPPER DISTURBANCE.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$


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