000
FXUS61 KPBZ 291849
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
249 PM EDT THU JUL 29 2010

.SYNOPSIS...
SURFACE HIGH PRESSURE WILL PROVIDE DRY WEATHER FOR TONIGHT AND
FRIDAY. AN UPPER LEVEL TROUGH WILL CROSS THE REGION DURING THE
WEEKEND BRINGING ISOLATED SHOWERS AND THUNDERSTORMS.

&&

.NEAR TERM /THROUGH FRIDAY/...
LOW LEVELS CONTINUE TO DRY OUT NORTH OF THE PA/WV BORDER AS
FRONTAL BOUNDARY SAGS SOUTHWARD. ISOLATED SHOWERS CONTINUE TO POP
UP OVER NORTHERN WV WHERE SURFACE DEW POINTS REMAIN IN THE LOWER
70S. EXPECT ANY REMAINING COVERAGE OF CONVECTION TO DISSIPATE
BEFORE EVENING.

HIGH PRESSURE WILL DRIFT EAST ACROSS THE GREAT LAKES TONIGHT AND
FRIDAY. TEMPERATURES WILL DROP INTO THE 50S OVERNIGHT. EXPECT
SURFACE WINDS TO DROP BELOW 5KT LATE TONIGHT AND BUFKIT SHOWS LOW
LEVEL INVERSION SETTING UP. SOME PATCHY FOG IS POSSIBLE IN RIVER
VALLEYS AND LOCATIONS THAT RECEIVED RAINFALL EARLIER TODAY.

TEMPERATURES SHOULD WARM INTO THE UPPER 70S AND LOWER 80S FRIDAY
AFTERNOON WITH COMFORTABLE DEW POINTS IN THE 50S.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL MOVE EAST INTO NEW ENGLAND FRIDAY
NIGHT. GFS AND ECMWF SHOW WEAK UPPER LEVEL SHORTWAVE IN NORTHWEST
FLOW ENTERING THE UPPER OH VALLEY SATURDAY WITH THE MAIN UPPER
TROUGH DEEPENING ALONG THE EAST COAST SUNDAY. KEPT ISOLATED POPS
FOR SHOWERS AND STORMS IN THE FORECAST FOR SATURDAY INTO
SUNDAY....WITH PRECIPITATION CHANCES INCREASING TO NEAR 30 PERCENT
ALONG THE RIDGES SUNDAY AFTERNOON AS TROUGH DEEPENS TO THE EAST.

TEMPERATURES SHOULD BE CLOSE TO NORMAL IN THE SHORT TERM.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE PERIOD BEGINS WITH GFS/ECMWF AGREEMENT THAT A LONG WAVE TROUGH
AXIS WILL BE CENTERED ACROSS THE MID-ATLANTIC. THE UPPER OHIO VALLEY
WILL BE IN A NORTHWESTERLY FLOW ON THE BACK SIDE OF THE TROUGH. THE
SLIGHT CHANCE OF SHOWERS AND STORMS REMAINS IN THE FORECAST FOR THE
EASTERN RIDGES WITH A CLOSER PROXIMITY TO THE TROUGH AXIS.

DESPITE THE NORTHWESTERLY FLOW ALOFT EARLY NEXT WEEK...A LOW
PRESSURE SYSTEM APPROACHING ACROSS THE GREAT LAKES WILL SHIFT LOW-
LEVEL FLOW TO MORE SOUTHWESTERLY...ALLOWING FOR DEW POINTS TO
RETURN TO THE MID 60S TUESDAY AND WEDNESDAY. IN THIS
PATTERN...CONVECTION CANNOT BE RULED OUT IN A WARM AND MOIST
ENVIRONMENT ON TUESDAY AHEAD OF A COLD FRONT. THE BETTER CHANCE
FOR SHOWERS AND STORMS WILL BE TUESDAY NIGHT INTO EARLY WEDNESDAY
WHEN THE COLD FRONT CROSSES THE UPPER OHIO VALLEY. HIGH PRESSURE
WITH MORE OF A ZONAL MID-LEVEL FLOW WILL THEN BUILD IN FOR
WEDNESDAY AND THURSDAY...ALLOWING FOR A DRY MID-WEEK.

IN A NORTHWESTERLY MID-LEVEL FLOW...NEAR NORMAL TEMPERATURES IN THE
LOWER TO MID 80S ACROSS MUCH OF THE AREA ARE EXPECTED FOR HIGHS ON
MONDAY. AHEAD OF THE FRONTAL BOUNDARY...AN INCREASED SOUTHERLY FLOW
WILL ALLOW FOR HIGHS A FEW DEGREES ABOVE NORMAL ON TUESDAY. WITH THE
MID-WEEK FRONTAL PASSAGE SHOWING WEAK TEMPERATURE ADVECTION...THIS
WILL HAVE LITTLE IMPACT ON HIGHS...WITH NEAR NORMAL VALUES EXPECTED
WEDNESDAY AND THURSDAY.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL ACROSS THE TERMINALS THIS EVENING AND
OVERNIGHT AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST IN THE WAKE
OF A COLD FRONT. NORTHWESTERLY WINDS WILL GUST UP TO 20 KTS INTO THE
EARLY EVENING ACROSS THE TERMINALS NORTH A KAGC-KLBE LINE. DIURNAL
CUMULUS CLOUDS WILL DIMINISH BEFORE SUNSET...WITH CLEAR SKIES AND
LIGHT WINDS OVERNIGHT. WITH ABUNDANT GROUND MOISTURE AND TD
DEPRESSIONS DROPPING TO LESS THAN 2 DEGREES...BELIEVE THAT
CONDITIONS WILL BE FAVORABLE FOR SOME BRIEF FOG DURING THE PRE-DAWN
HOURS ON FRIDAY. TEMPO GROUPS ARE FORECAST FOR IFR VISIBILITIES AT
KDUJ/KZZV WITH MVFR VISIBILITIES EXPECTED OTHERWISE.

HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN FRIDAY INTO EARLY
SUNDAY WITH VFR CONDITIONS PREVAILING. INCREASED MOISTURE WITH AN
UPPER LEVEL DISTURBANCE PASSING ON SUNDAY WILL ALLOW FOR THE CHANCE
OF SHOWERS AND THUNDERSTORMS WITH RESTRICTIONS TO RETURN SUNDAY
AFTERNOON INTO EARLY ON MONDAY. ASIDE FROM SOME POSSIBLE PRE-DAWN
VISIBILITY RESTRICTIONS WITH RIVER VALLEY FOG...VFR CONDITIONS
SHOULD PREVAIL EARLY NEXT WEEK AS THE FOCUS OF CONVECTION REMAINS
EAST OF THE TERMINALS ACROSS THE MID-ATLANTIC.

&&

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

&&

$$

NWS PBZ Office Area Forecast Discussion