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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 180422
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1222 AM EDT SAT MAY 18 2013

.SYNOPSIS...
-- Changed Discussion --
SEASONABLY WARM WEATHER WILL CONTINUE OVER THE WEEKEND...BUT THE
CHANCE OF AN AFTERNOON SHOWER OR POSSIBLY A THUNDERSTORM WILL ALSO
BE IN THE FORECAST.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TODAY/...
-- Changed Discussion --
1215 AM UPDATE...
WILL INTRODUCE SLIGHT CHANCE POP ACROSS EXTREME NE
SECTION WITH SCATTERED SHOWERS MOVING ACROSS LAKE INTO PA. WILL
TAKE OUT CHANCE POPS ACROSS SOUTH...DOUBTFUL ANY PRECIP MAKES IT
BY MORNING.

REST OF PREVIOUS DISCUSSION FOLLOWS... SHWRS AND TSTMS
WERE STILL CONFINED TO AREAS SOUTH OF A PARKERSBURG TO CLARKSBURG
WV LINE...SOUTH OF FRONTAL BOUNDARY BEST INDICATED VIA SFC
DEWPOINTS AND LGT...BUT CONVERGENT WIND.

HAVE THUS MAINTAINED A DRY FORECAST FOR TNGT...WITH EXCEPTION FOR
THE RIDGES OF TUCKER AND GARRETT COUNTY WHERE UPSLOPE ENHANCEMENT
MAY SPPRT SOME LGT SHWRS AS THE FRONT BGNS A NWD DRIFT.

OTHERWISE...MODELS CONTINUE TO SUGGEST THAT THE FRONT WILL ONCE
AGAIN FLUCTUATE ACROSS THE REGION SATURDAY. THE BIGGEST QUESTION
WILL BE THE NORTHERN EXTENT OF LIFT FROM AN APPROACHING SHORTWAVE
THAT IS PROGGED TO REACH THE REGION IN THE AFTERNOON. EACH OF THE
DETERMINISTIC MODELS HANDLES THIS DIFFERENTLY...THUS NOTHING MORE
THAN CHANCE POPS WERE ADDED SATURDAY AFTERNOON. WITH MORE CLOUD
COVER EXPECTED SATURDAY...TEMPERATURES WERE KEPT A FEW DEGREES
COOLER THAN TODAY.
-- End Changed Discussion --

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
THE BOUNDARY SHOULD MAKE IT`S FINAL PUSH NORTHWARD BY SATURDAY
NIGHT/SUNDAY LEADING TO BETTER MOISTURE AND INSTABILITY THROUGH
THE REMAINDER OF THE SHORT TERM. HOWEVER SHORTWAVE TIMING AND
PLACEMENT CONTINUES TO DIFFER OWING TO LOWER CONFIDENCE IN THUNDERSTORM
COVERAGE. SO CHANCE POPS WERE CONTINUED...MAINLY IN THE AFTERNOONS
BOTH SUNDAY AND MONDAY.

STRENGTHENING SOUTHERLY FLOW SHOULD ALLOW TEMPERATURES TO WARM
EACH DAY...EVEN IF THERE IS CLOUD COVER SO HIGHS IN THE LOWER 80`S
WERE INTRODUCED BY MONDAY AFTERNOON.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
UPPER LEVEL RIDGING WILL CONTINUE TO AMPLIFY OVER THE EASTERN
HALF OF THE CONUS AS A CUTOFF LOW DEVELOPS OVER THE NORTHERN
PLAINS. THIS LOW WILL SLOWLY MAKE IT`S APPROACH THROUGH THE
PERIOD...HELPING TO SWING AN ASSOCIATED FRONT ACROSS THE REGION BY
LATE WEDNESDAY/EARLY THURSDAY. HOWEVER...DIFFERENCES STILL REMAIN
IN THE AMOUNT OF CONVECTIVE ACTIVITY THERE WILL BE IN THE WARM
SECTOR TUESDAY AND WEDNESDAY AS DIFFERENT SHORTWAVES MOVING
THROUGH THE UPPER LEVEL FLOW ARE TIMED DIFFERENTLY FROM RUN TO
RUN.

GIVEN THESE DIFFERENCES...OPTED TO REMAIN CONSERVATIVE WITH POPS
UNTIL LATE TUESDAY BEFORE INCREASING CHANCES IMMEDIATELY AHEAD OF
THE COLD FRONT. TEMPERATURES WERE KEPT NEAR MOS/HPC GUIDANCE BUT
AMPLE MOISTURE AND CLOUD COVER COULD PRECLUDE READINGS FROM REACHING
THE MID 80`S AS SUGGESTED.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...

-- Changed Discussion --
VFR FORECAST TODAY. WILL START WITH A SCT-BKN CIRRUS DECK. AS THE
EARLY MORNING PROGRESSES AND AREA OF MID CLOUDS WILL MOVE ACROSS
NORTHERN PORTS AND AREA OF MID CLOUDS WILL MOVE INTO SOUTHERN
PORTS. THIS SOUTHERN DECK WILL DECAY BY LATE MORNING...ALLOWING
FOR SUNSHINE AND THE DEVELOPMENT OF CU. IT IS POSSIBLE THAT A
SHOWER OR STORM COULD DEVELOP OVER PORTS SOUTH OF PIT IN THE
AFTERNOON...BUT WITH LOW CONFIDENCE AT CONVECTION HITTING ANY
PARTICULAR PORT... WILL INSTEAD INDICATE CB.

.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
THERE WILL BE AN INCREASING CHC FOR RESTRICTIONS IN DIURNALLY SPPRTED
SCT SHOWERS AND THUNDERSTORMS DURING THE FIRST HALF OF THE WEEK.
-- End Changed Discussion --

&&

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

&&

$$