-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 180625
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
225 AM EDT TUE JUN 18 2013

.SYNOPSIS...
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AN UPPER LEVEL DISTURBANCE WILL CREATE PERIODIC SHOWERS AND
THUNDERSTORMS ALONG A STALLED FRONTAL BOUNDARY THROUGH TUESDAY
NIGHT. HIGH PRESSURE WILL KEEP CONDITIONS DRY AND NEAR AVERAGE
TEMPERATURES FOR THE REST OF THE WEEK.
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&&

.NEAR TERM /THROUGH TODAY/...
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BROAD UPPER LEVEL SHORTWAVE TROUGH WILL MOVE EASTWARD WHILE AT
THE SURFACE...WEAK COLD FRONT CURRENTLY PLACED ALONG LAKE ERIE
WILL PROGRESS SOUTHWARD. INITIALLY...THE SITUATION WILL HELP
ENHANCE SHOWERS AND POSSIBLE THUNDERSTORMS THROUGH EARLY TUESDAY.
ANOTHER SHORTWAVE MOVING ACROSS THE MID-ATLANTIC WILL MOVE
EAST/NORTHEAST AND LOW LEVEL CONVERGENCE BETWEEN THE SURFACE LOW AND
SOUTHWARD COLD FRONT SHOULD ENHANCE SHOWERS AND THUNDERSTORMS IN
THE AFTERNOON...MAINLY SOUTH OF PIT.

SKY COVERAGE WILL BE MOSTLY CLOUDY. HENCE...LIMITED INSTABILITY
WILL PERSIST THROUGH THE AFTERNOON. HOWEVER...MODEST MID-LEVEL
FLOW WILL ENHANCE CONVECTION...YIELDING AT LEAST LOW PROBABILITIES
OF SEVERE THUNDERSTORMS.
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&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...
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MODELS IN FAIR AGREEMENT WITH TIMING OF FRONT TO MOVE SOUTH OF THE
FORECAST AREA BY TONIGHT. HIGH PRESSURE WILL SETTLE OVER THE REGION AND
KEEP TEMPERATURES COOLER THAN NORMAL WEDNESDAY AND THURSDAY.
WARMER THAN AVERAGE TEMPERATURES WILL FOLLOW ON FRIDAY AS WARM AIR
ADVECTION FROM THE SOUTHWEST BEGINS TO PERSIST.
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&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MDLS CONT TO DEPICT DVLPMNT OF A BROAD SRN CONUS RIDGE FOR THE
LONG TERM PD WITH GENL RIDGE AXIS POSITIONING ACRS THE GREAT
LAKES. WARMER TEMPS ARE THUS IN STORE FOR THE UPR OH VALLEY REGION
WITH WEEKEND READINGS PROGGED WELL INTO THE 80S AS PER HIGHER MOS
GUIDANCE.

GRADUALLY INCRSG POPS...TO CHC NMBRS FOR THE WEEKEND...WERE ALSO
INCLUDED...BUT TIMING WL BE DEPENDENT ON SHRTWV PASSAGE ACRS THE
NRN PERIPHERY OF THE RIDGE...SO CONFIDENCE IN THAT PARAMETER IS
MINIMAL AT THIS JUNCTURE OF THE FORECAST PROCESS.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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GENL VFR IS ANTICIPATED THIS MRNG...BUT SVRL FEATURES MAY MAR THE
FORECAST WITH POTENTIAL RESTRICTIONS.  PATCHY MVFR FOG IS POSSIBLE
THRU THE PREDAWN GIVEN THE MOIST BNDRY LYR...BUT HIGH MDL-PROGGED
CONDENSATION PRES DEFICITS AND DRY ADVCTN ABOVE THE SFC LYR ARE
EXPECTED TO PRECLUDE WIDESPREAD IFR RESTRICTIONS.

OTHERWISE...SCT SHWRS ARE EXPECTED TO DVLP TNGT...AND BECOME
MORE WIDESPREAD BY TUE AFTN AS A CDFNT SAGS ACRS THE UPR OH VALLEY
REGION.  THE BTR CHC FOR TERMINAL AFFECTS WL BE FOR PORTS S OF PIT
AS HEATING/DESTABILIZATION MAY SPPRT MORE WIDESPREAD SHWR AND TSTM
DVLPMNT IN CONJUNCTION WITH FRONTAL PROGRESS.

OUTLOOK.../TONIGHT THROUGH SATURDAY/...
RESTRNS ARE PSBL S OF PIT TNGT AS THE CDFNT EXITS...BUT BLDG HIGH
PRES IS EXPD TO PRODUCE GENL VFR FOR THE RMNDR OF THE WEEK.
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&&

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

&&

$$