-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 232337
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
737 PM EDT WED JUL 23 2014

.SYNOPSIS...
SHOWER AND THUNDERSTORM CHANCES WILL DIMINISH WITH PASSAGE OF A
COLD FRONT THIS EVENING.

&&

.NEAR TERM /THROUGH THURSDAY/...
545 PM UPDATE...PREFRONTAL TROUGH IS ALMOST ENTIRELY THROUGH
CWA...BUT THE LAGGING DEWPOINT BOUNDARY IS JUST PAST DUJ AND
APPROACHING BTP. THIS WILL BE THE REAL POP CUTOFF THIS
EVENING...AND HAVE TIMED THE GRIDS TO THIS THINKING. THINK THIS
PASSES THROUGH PIT AROUND 00Z AND THEN SLOWS UP AS IT APPROACHES
THE MASON/DIXON LINE LATER THIS EVENING. THUNDER IS ALREADY WANING
AND HAVE REDUCED PROBABILITIES ACCORDINGLY. NEXT UPDATE WILL
REDUCE POPS EVEN FURTHER IF CURRENT TRENDS CONTINUE. ALSO UPDATED
SKY/WIND GRIDS FOR TRENDS.

PREVIOUS DISCUSSION...


EARLY AFTN UPDATE WAS ISSUED TO FURTHER ADJUST HOURLY TRENDS OF
POPS AND TEMPS AS THE CDFNT ENCROACHES ON THE UPR OH VALLEY REGION.
SFC WIND IS ALREADY VEERING WITH PASSAGE OF PREFRONTAL TROF...BUT
APPRECIABLY DRIER AIR SHOULD NOT BE ANTICIPATED UNTIL TNGT.
LIKELY POPS WERE ADJUSTED SWD WITH EXPECTATIONS OF AFTN/EARLY EVE
SHRTWV SPPRT AND HIGHER INSTABILITY VIA HEATING AND SFC DEWPOINTS
ARND 70F. POP DIMINISHMENT FM THE NW CAN BE EXPECTED AS THE
EVE...AND FRONT PROGRESS THIS EVE.

NR TERM TEMPS WERE BASED ON PERSISTENCE TWEAKED VIA NAM GUIDANCE.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
LINGERING SLGT...TO CHC NMBRS WERE RETAINED FOR AREAS S AND E OF
PIT THROUGH EARLY THURSDAY GIVEN THE PROG OF ANOTHER SHRTWV ACRS
THE STABILIZING UPR OH REGION.

COOLER AND DRIER AIR WL BE ADVECTING OVR THE ENTIRE REGION
THROUGH THE SHORT TERM PD. TEMPS WERE FORECAST CLOSER TO BIAS
CORRECTED GFS MOS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
LOW CONFIDENCE FORECAST FOR THE BEGINNING OF THE LONG TERM PERIOD.
MODELS EXPLORING SOME DIFFERENT OPTIONS WITH A SHORTWAVE TROUGH
THAT WILL CROSS THE AREA SOMETIME ON SATURDAY. THIS PART OF THE
FORECAST WILL NEED TO BE REFINED ONCE MODEL RUN TO RUN BECOMES
MORE CONSISTENT.

THE NEXT SYSTEM WILL BRING SHOWERS AND STORMS TO THE AREA SUNDAY
AND MONDAY AND MUCH COOLER AIR FOR THE END OF THE LONG TERM.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
DIFFICULT AVIATION FORECAST TONIGHT AS THE FRONT HAS JUST ABOUT
PUSHED THROUGH ALL TERMINALS NEARING 00Z. DEWPOINTS ARE FALLING
QUICKLY BEHIND THE FRONT AND COLD AIR ADVECTION HAS DEVELOPED SOME
STRATOCU IN THE WAKE. SATELLITE IMAGERY OFFERS A PRETTY RAGGED
DEPICTION OF THE CLOUD DECK THAT IS FAR FROM UNIFORM. ALTHOUGH
MANY OF THE SITES CIGS WILL BOUNCE TONIGHT...THE OVERALL TREND IS
TO DROP CIGS INTO THE MVFR RANGE WITH A FEW CROSSING IFR
THRESHOLDS.

THURS ANY STRATUS WILL GIVE WAY TO A SCT TO BKN CLOUD DECK NEARING
5KFT. VFR CONDITIONS SHOULD PREVAIL THERE ON WITH HIGH PRESSURE
BUILDING IN.

OUTLOOK.../WEDNESDAY THROUGH SUNDAY/...
THE NEXT CHANCE FOR RESTRICTIONS WILL COME LATER SATURDAY AND
SUNDAY AS LOW PRESSURE APPROACHES.
-- End Changed Discussion --

&&

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

&&

$$