051
FXUS61 KPBZ 190614
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
214 AM EDT SAT SEP 19 2026
WHAT HAS CHANGED
THERE HAS COME TO A BE A BIT MORE AGREEMENT IN THE POTENTIAL OF
HEAVY RAINFALL THIS WEEKEND AND INTO NEXT WEEK.
KEY MESSAGES
1) RAIN CHANCES RETURN SUNDAY INTO EARLY NEXT WEEK. RAIN MAY BE
HEAVY AT TIMES, AND COULD LEAD TO LOCALIZED FLOODING AND/OR RIVER
RISES.
DISCUSSION
KEY MESSAGE 1...
ANOTHER PERIOD OF EXTENDED WET WEATHER IS FORECAST TO ENTER THE
AREA SATURDAY NIGHT AND INTO SUNDAY MORNING. ASCENT WILL MOSTLY
BE DUE TO A SHORTWAVE TROUGH AND RIDGE BREAKDOWN IN A TRANSITION
TO MORE QUASI-ZONAL FLOW FOR THE BEGINNING OF NEXT WEEK.
THE FIRST ROUND WILL ARRIVE SATURDAY NIGHT INTO SUNDAY WITH THE
BULK OF THE MOISTURE AXIS FOCUSED OVER THE NORTHERN FORECAST
AREA TO BEGIN THE WET PERIOD. THE TOTALS UP NORTH POINT TO THE
HREF GIVING A 60% TO 70% PROBABILITY OF EXCEEDING 0.50".
HOWEVER, THE 90TH PERCENTILE HERE SHOWS SOME 1.00" TO 1.75" 24
HOUR RAINFALL AMOUNTS. WITH PWAT AMOUNTS IN THE 1.8 TO 2.0
RANGE, A 90TH PERCENTILE AMOUNT IS CERTAINLY MORE PROBABLE. THE
HEAVIEST RAINFALL IS EXPECTED ARRIVE BY SUNDAY MORNING IN THE
12Z TO 16Z TIMEFRAME.
THIS 24 TO 36 HOURS PERIOD WILL LIKELY CONSIST OF A FEW WAVES OF
CONVECTION BRINGING HEAVY RAINFALL TO THE REGION. THE OTHER
ISSUE WILL BE THE MU CAPE VALUES FOR SUNDAY TOPS OFF AT AROUND
1000 J/KG AND THIS MAY BE ENOUGH TO INCREASE THE EFFICIENCY IN
THE RAINFALL RATES. WHILE THERE LIKELY WON'T BE ENOUGH
INSTABILITY FOR SEVERE CONCERNS, THERE IS QUITE A BIT OF LOW
LEVEL SHEAR IN PLACE. WILL NEED TO WATCH FOR AN ISOLATED SPIN-
UP.
CONTINUED RAIN CHANCES ARE FORECAST INTO MONDAY, TUESDAY, AND
WEDNESDAY, THOUGH TEMPERATURES WILL BE COOLER AND RAIN IS
EXPECTED TO BE MOSTLY STRATIFORM. THAT BEING SAID, LONG DURATION
ACCUMULATIONS HAVE THE POTENTIAL TO BE SIZABLE, WITH 90TH
PERCENTILE 48HR TOTALS OF UP TO 2" TO 4". WHILE THIS WOULDN'T
POSE AS MUCH A THREAT FOR FLASH FLOODING, AREAL FLOODING AND
RIVER FLOODING CHANCES MAY INCREASE SHOULD THIS HIGH-END
POTENTIAL BE REALIZED. THE PRIMARY WAY TO REALIZE HIGH END
POTENTIAL WOULD BE TO BE POSITIONED IMMEDIATELY NORTH OF THE
STATIONARY BOUNDARY WITH OVERRUNNING AND/OR ON THE NORTHWEST
SIDE OF A DEVELOPING COASTAL LOW. SHOULD THE STATIONARY BOUNDARY
BE TOO FAR SOUTH OR THE COASTAL LOW TO FAR EAST, THESE THREATS
WOULD NOT BE REALIZED. THESE SCENARIOS WILL NEED TO BE
MONITORED THROUGH THE WEEKEND AND INTO NEXT WEEK.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
EXPECT MAINLY VFR CONDITIONS TONIGHT WITH THE EXCEPTION OF MGW
AND HLG WHERE SOME FOG DEVELOPMENT IS POSSIBLE. OTHERWISE,
EXPECTED LIGHT AND VARIABLE WINDS THROUGH THE REST OF THE NIGHT
AND INTO THE COMING DAY. THE NEXT SYSTEM TO IMPACT THE AREA WILL
ARRIVE LATE TONIGHT. HAVE PUT SOME PROB30S AT FKL, DUJ, ZZV, AND
PIT TO COVER THE POTENTIAL ARRIVAL OF PRECIP TOWARDS THE END OF
THE TAF PERIOD. SOME MVFR IMPACTS ARE POSSIBLE WITH THIS
ARRIVAL.
OUTLOOK... RESTRICTIONS ARE LIKELY TO RETURN SATURDAY NIGHT INTO
SUNDAY MORNING WITH AN INCREASED CHANCE FOR SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH AN APPROACHING DISTURBANCE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...MILCAREK/SHALLENBERGER
AVIATION...SHALLENBERGER
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