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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 231515
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1115 AM EDT THU MAY 23 2013

.SYNOPSIS...
SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE UNTIL A FRONT CROSSES
THE REGION THIS EVENING. MUCH COOLER WEATHER CAN BE EXPECTED FOR
THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
A BIT OF A DRIER PERIOD BEHIND LAST NIGHT`S WAVE THAT IS DEPARTING
TO THE EAST LOOKS IN STORE FOR THE MORNING HOURS. HOWEVER...A
SECONDARY WAVE MOVES TOWARD THE AREA FOR THIS EVENING...AND IN
ADVANCE OF IT...MID-LEVEL COOLING WHILE THE BOUNDARY LAYER WARMS
SHOULD STEEPEN LAPSE RATES RATHER TREMENDOUSLY THIS AFTERNOON. AS
A RESULT...SHOWERS SHOULD FLOURISH ACROSS THE AREA THIS
AFTERNOON...BUT PARTICULARLY ACROSS THE WESTERN...NORTHERN...AND
RIDGE ZONES. WITH THE STEEPENED LAPSE RATES...MODEST CAPE VALUES
ARE EVIDENT ON ALL GUIDANCE WITH DECENT SHEAR SO A FEW
THUNDERSTORMS WITH SOME GUSTY WIND AND HAIL ARE LIKELY.
ADDITIONALLY...DUE TO MORE PERVASIVE CLEARING AHEAD OF THE SECOND
WAVE...TEMPERATURES ARE JUMPING PRETTY EFFICIENTLY THIS MORNING.
HIGHS WERE INCREASED OVERALL DUE TO ADDITIONAL INSOLATION
EXPECTATIONS. THIS MEANS WE HAVE ALREADY ECLIPSED OUR CONVECTIVE
TEMPERATURES...SO SHOWERS AND THUNDERSTORMS SHOULD QUICKLY BECOME
MORE INCREASED IN CONVERAGE. FRIES
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THE CDFNT WL COMPLETE A SWEEP OF THE REGION TNGT...BUT CHC POPS
WERE MAINTAINED INTO FRIDAY GIVEN THE PRESENCE OF THE MID/UPR
TROF. BLDG HIGH PRES SHOULD SUPPRESS THOSE RESIDUAL CHCS BY FRIDAY
AFTN.

ISSUE THEREAFTER IS OF TEMPS AS DVLPMNT OF A HIGH AMPLITUDE ERN
CONUS TROF SPPRTS STRNG COLD ADVCTN. SHOULD SFC WIND DIMINISH
SUFFICIENTLY...PTCHY FROST IS PSBL BY DAYBREAK SATURDAY.

SHORT TERM TEMPS WERE FORECAST USING A BLEND OF PERSISTENCE AND
SREF MEANS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
DRY WEA IS EXPD THRU THE PERIOD WITH HIGH PRESSURE IN CONTROL. A
WRMFNT MAY APRCH BY MID WEEK BUT TOO MUCH UNCERTAINTY TO INCLUDE
ANY PCPN MENTION ATTM. TEMPS WL START OUT BLO AVG OVR THE
WEEKEND...THEN MODERATE TO SEASONAL LVLS AS HIGH PRESSURE SHIFTS E
OF THE AREA AND FLOW TURNS SRLY.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
MVFR CIGS ARE POSSIBLE FOR A BRIEF TIME THIS MORNING BEFORE
LIFTING TO VFR AT ALL PORTS. SHOWERS WILL DEVELOP AGAIN THIS
AFTERNOON...WITH A CHANCE OF THUNDERSTORMS AS WELL. CONFIDENCE IN
TSTMS IS NOT HIGH ENOUGH TO INCLUDE IN TAFS. AS A COLD FRONT
APPROACHES THE AREA THIS EVENING...WIND GUSTS ARE EXPECTED TO PICK
UP AS WELL AS THE ARRIVAL OF MVFR CIGS. WINDS WILL VEER TO THE
NORTHWEST BEHIND THE FRONT...AND WIDESPREAD IFR CONDITIONS ARE
EXPECTED AFTER MIDNIGHT.

.OUTLOOK.../FRIDAY THROUGH MONDAY/...
RESTRNS ARE LIKELY WITH REMAINING SHWRS INTO FRIDAY...BUT BLDG
HIGH PRES WL QUICKLY RTN VFR TO AREA PORTS BY AFTN. GENL VFR WL
THEN PERSIST INTO EARLY NEXT WEEK.

&&

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

&&

$$