643
FXUS61 KPBZ 211117
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
717 AM EDT THU MAY 21 2026
WHAT HAS CHANGED
NO MAJOR CHANGES WERE MADE TO THE FORECAST. PERIODIC RAIN AND
POSSIBLE THUNDERSTORMS EXPECTED FRIDAY AND SATURDAY. MORE
INTERMITTENT SHOWERS/POSSIBLE THUNDERSTORMS SUNDAY AND MONDAY.
KEY MESSAGES
1) RAIN CHANCES DECREASE FROM N-S TODAY
2) ROUNDS OF RAIN AND POSSIBLE THUNDERSTORMS LATER FRIDAY INTO EARLY
NEXT WEEK. LOCALLY HEAVY RAINFALL POSSIBLE ESPECIALLY FRIDAY NIGHT
INTO SATURDAY NIGHT. GUSTY DOWNSLOPE WIND ALSO POSSIBLE FRIDAY AND
SATURDAY.
DISCUSSION
KEY MESSAGE 1...
A COLD FRONT WAS LOCATED FROM THE MID ATLANTIC TO THE LOWER
OHIO VALLEY. A SHORTWAVE TRACKING ALONG THE NORTHERN SIDE OF
THE FRONT WILL CONTINUE TO BRING RAIN TO AREAS SOUTH OF I-80
EARLY THIS MORNING, THOUGH THESE CHANCES WILL DECREASE FROM N-S
AS THE WAVE GRADUALLY EXITS AND THE FRONT DROPS SLOWLY SOUTH.
AREAS SOUTH OF THE I-68 CORRIDOR WILL BE THE LAST TO SEE THE
RAIN END LATE TODAY. HIGHS ARE EXPECTED TO BE 5 TO 10 DEGREES
BELOW AVERAGE.
KEY MESSAGE 2...
A TROUGH IS EXPECTED TO ADVANCE EASTWARD FROM THE CENTRAL CONUS
ON FRIDAY. INCREASING MOISTURE AND ASCENT IN WARM ADVECTION IN
SOUTHWEST FLOW AHEAD OF THE TROUGH, AND A SURFACE WARM FRONT
LIFTING NORTHWARD, WILL RESULT IN RAIN CHANCES INCREASING FROM
S-N FRIDAY. WIDESPREAD RAIN IS EXPECTED FRIDAY NIGHT INTO
SATURDAY AS THE WARM FRONT CONTINUES LIFTING NORTH ACROSS THE
REGION. PRECIPITABLE WATER IS PROGGED TO INCREASE TO BETWEEN
1.5 AND 1.75 BY SATURDAY MORNING, WITH CONTINUED WARM, MOIST
ADVECTION. THERE IS SOME INDICATION OF VERY LIMITED ELEVATED
INSTABILITY, WITH THE THUNDER POTENTIAL LOW. THE WARM FRONT
SHOULD BE NORTH OF THE REGION BY SATURDAY NIGHT, WITH SHOWERS
AND POSSIBLE THUNDERSTORMS AS THE UPPER TROUGH AXIS CROSSES THE
REGION. CURRENT NBM PROBABILITIES INDICATE A 60-80 PERCENT
CHANCE OF AT LEAST ONE INCH OF RAIN FROM FRIDAY THROUGH EARLY
SUNDAY MORNING, WITH A 30-50 PERCENT CHANCE OF 2 INCHES.
PROBABILITIES ARE LOWER ON THE LEE SIDE OF THE RIDGES, WHERE
SOME LOW LEVEL DOWNSLOPING IS LIKELY. LOCALIZED FLOODING WILL
BE POSSIBLE IN FLOOD PRONE AREAS, AND WHERE HEAVIER RAIN
PERSISTS.
THE DOWNSLOPING SHOULD RESULT IN GUSTY SE WIND ESPECIALLY ON
THE LEE SIDE OF THE LAUREL HIGHLAND RIDGES, DEVELOPING FRIDAY
AND CONTINUING SATURDAY. AT THIS TIME, IT LOOKS AS THOUGH
INVERSION HEIGHTS SHOULD KEEP GUSTS IN THE 30-35 KT RANGE,
THOUGH THESE GUSTS COULD BE PERSISTENT THROUGH THIS PERIOD.
GUSTS SHOULD DIMINISH SATURDAY NIGHT AS THE FLOW VEERS TO THE
SOUTH AND LOW LEVEL WIND DIMINISHES.
WHILE SHOWER AND THUNDERSTORM CHANCES CONTINUE SUNDAY, THEY
SHOULD BE MORE LIMITED AND NOT AN ALL DAY RAIN WITH THE AREA IN
BETWEEN THE EXITING SHORTWAVE IN THE MORNING, AND AN
APPROACHING SHORTWAVE ACROSS THE MIDWEST. THE MIDWESTERN
SHORTWAVE/SURFACE TROUGH SHOULD TRACK ACROSS THE REGION SUNDAY
NIGHT, WITH HIGHER SHOWER/STORM CHANCES. MORE UNCERTAINTY
EXISTS FOR MONDAY. PRECIP CHANCES WILL DEPEND ON WHERE THE
SURFACE TROUGH STALLS ACROSS THE LOWER OHIO VALLEY REGION.
MAINTAINED THE NBM POPS WITH A VARIETY OF MODEL ENSEMBLE
SOLUTIONS AND UNCERTAINTY.
ENSEMBLE RIVER FORECASTS INDICATE ELEVATED RIVER LEVELS ARE
LIKELY BEGINNING OVER THE WEEKEND INTO NEXT WEEK.
AVIATION /12Z THURSDAY THROUGH MONDAY/
POST-FRONTAL LIGHT RAIN CONTINUES TO SLOWLY SHIFT SOUTH AND EAST
THIS MORNING AS DRIER AIR SETTLES IN FROM THE NORTH. AS OF 12Z,
THE CUTOFF SITS JUST SOUTH OF A LINE FROM ZZV TO HLG TO AGC.
IFR CEILINGS WILL LINGER AT TERMINALS WITH RAIN (LBE/MGW)
THROUGH THE MORNING. LBE SHOULD EVENTUALLY LIFT TO VFR THIS
AFTERNOON, BUT MVFR/IFR CEILINGS WILL LIKELY LINGER AT MGW
THROUGH THE REMAINDER OF THE TAF PERIOD AS THE FRONT STALLS
ACROSS CENTRAL/NORTHERN WV.
WIND AROUND 10 KNOTS WILL SLOWLY VEER FROM NORTH TO EAST TODAY.
RESTRICTIONS ARE LIKELY TO SPREAD NORTH AGAIN ON FRIDAY AS RAIN
LIFTS FROM THE SOUTH WITH A WARM FRONT.
OUTLOOK...
WIDESPREAD RESTRICTIONS IN RAIN ARE EXPECTED TO OVERSPREAD THE
REGION FROM S-N FRIDAY AFTERNOON INTO SATURDAY WITH A WARM
FRONT. SOME IMPROVEMENT IS POSSIBLE SUNDAY UNTIL A COLD FRONT
APPROACHES LATER IN THE DAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...WM
AVIATION...RACKLEY/CL
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