-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 171728
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
128 PM EDT MON JUN 17 2013

.SYNOPSIS...
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A FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF THE UPPER OHIO
VALLEY...ALLOWING THE CHANCE OF SHOWERS AND THUNDERSTORMS TO
CONTINUE THROUGH THE DAY ON TUESDAY. HIGH PRESSURE WILL THEN MOVE
INTO THE REGION FROM THE NORTHWEST...ALLOWING FOR DRY AND
SEASONABLE WEATHER FOR WEDNESDAY AND THURSDAY.
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&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
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AN ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO DECREASE
POPS SOUTH OF THE MASON-DIXON LINE EARLY THIS AFTERNOON.

THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A WEAK AND BROAD
CYCLONIC FLOW ACROSS THE UPPER OHIO VALLEY WITH DRIER AND SLIGHTLY
WARMER AIR ADVECTING IN FROM THE WEST. 850MB CONVERGENCE ALONG THE
MASON-DIXON LINE HAS WEAKENED MOSTLY WITH ONLY AN ISOLATED SHOWER
OR TWO REMAINING ACROSS THE ALLEGHENY FRONT. THE CONVERGENCE ZONE
HAS BEEN CO-LOCATED WITH A FRONTAL BOUNDARY NEAR THE MASON-DIXON
LINE. ALTHOUGH A THERMAL GRADIENT IS LACKING ALONG THE BOUNDARY...IT
CAN BE MORE EASILY DEPICTED BY SURFACE DEW POINT AND EQUIVALENT
POTENTIAL TEMPERATURE GRADIENTS.

THIS AFTERNOON...THE FRONTAL BOUNDARY WILL REMAIN FAIRLY
STATIONARY IN THE VICINITY OF THE MASON-DIXON LINE. THERE ARE TWO
POTENTIAL CONTRIBUTORS THAT HAVE LED TO THE FORECAST FOR POSSIBLE
ISOLATED CONVECTION THIS AFTERNOON...THE FRONTAL BOUNDARY AND
INSTABILITY INCREASING TO 1500-2500 J/KG SBCAPE PRIMARILY SOUTH OF
PITTSBURGH. WITH THIS AND THE 14Z HRRR IN MIND HAVE GONE WITH SCHC
POP THROUGH MUCH OF THE AFTERNOON/EVENING. FOR TEMPS...UTILIZED RECENT
TRENDS IN OBS ALONG WITH RAP 850MB TEMPS TO GO A FEW DEGREES ABOVE
A MAV/MET BLEND. HIGHS TODAY WILL REACH THE LOWER 80S ACROSS MOST
LOCATIONS WITH HIGHS IN THE MID 70S ACROSS THE HIGHER ELEVATIONS
OF WV/MD.
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&&

.SHORT TERM /8 PM THIS EVENING THROUGH THURSDAY/...
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CHC POPS WERE MAINTAINED TONIGHT...BUT SHIFTED SWD INTO TUESDAY AS
SECONDARY FRONT/OUTFLOW PROGRESS AS ANOTHER DISTURBANCE/JET STREAK
CROSS THE REGION.

DRY HIGH PRES WL BLD THEREAFTER AND SUPPRESS PCPN FOR WEDNESDAY
AND THURSDAY...BUT SEASONABLY COOL AIR UNDR TROFG ALOFT WL LIMIT
TEMP RECOVERY.
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&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
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 DEPENDANT 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 /18Z MONDAY THROUGH SATURDAY/...
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VFR CONDITIONS WILL MOSTLY PREVAIL THROUGH THIS EVENING...ALTHOUGH BRIEF
RESTRICTIONS WILL BE POSSIBLE IN ISOLATED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON WITH THE CHANCE INCREASING TONIGHT.
HAVE NOT INCLUDED THUNDERSTORMS IN THE TAFS THROUGH 12Z AT THIS
MOMENT AS COVERAGE WILL BE TOO SPARSE...ALTHOUGH IF A SHOWER/STORM
HITS A TERMINAL VISIBILITY RESTRICTIONS COULD BRIEFLY DROP TO IFR.
WINDS WILL BE SOUTHWESTERLY THIS AFTERNOON AT 5-10KTS.

A BRIEF PERIOD OF RESTRICTIONS WITH FOG/MIST WILL BE POSSIBLE
DURING THE PRE-DAWN HOURS ON TUESDAY. IFR CONDITIONS ARE FORECAST
ALONG AND SOUTH OF THE BOUNDARY AT KMGW/KZZV WITH MVFR ELSEWHERE. A
FRONTAL BOUNDARY WILL PUSH ACROSS THE AREA ON TUESDAY...WITH A
BETTER CHANCE OF BRIEF IFR RESTRICTIONS WITH SHOWERS AND
THUNDERSTORMS ACROSS THE TERMINALS DURING THE DAY.

OUTLOOK.../TUESDAY NIGHT THROUGH FRIDAY/...
THE FRONTAL BOUNDARY WILL PUSH SOUTHEAST OF THE AREA TUESDAY
NIGHT...BRINGING SHOWERS AND THUNDERSTORMS TO AN END. HIGH
PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST...ALLOWING FOR VFR
CONDITIONS TO PREVAIL FOR THE MAJORITY ON WEDNESDAY THROUGH FRIDAY.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AVIATION...WOODRUM