168
FXUS61 KPBZ 051735
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
135 PM EDT FRI SEP 5 2025
SYNOPSIS
SHOWERS AND POSSIBLE THUNDERSTORMS RETURN TONIGHT THROUGH PART
OF SATURDAY WITH A CROSSING COLD FRONT. MAINLY DRY WEATHER THEN
RETURNS UNDER HIGH PRESSURE SUNDAY THROUGH NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- SHOWERS AND POSSIBLE THUNDERSTORMS RETURN TONIGHT
- LOW POTENTIAL FOR STRONG STORMS
---------------------------------------------------------------
GENERALLY DRY WEATHER WILL CONTINUE THROUGH LATE AFTERNOON AHEAD
OF AN APPROACHING COLD FRONT. GUSTY SW WIND WILL CONTINUE UNTIL
MIXING DIMINISHES EARLY THIS EVENING.
A SHORTWAVE TROUGH, AND ITS ASSOCIATED SURFACE COLD FRONT, WILL
APPROACH THE REGION LATE THIS AFTERNOON, CROSSING THE UPPER
OHIO VALLEY REGION TONIGHT. SHOWER AND THUNDERSTORM CHANCES WILL
INCREASE THIS EVENING AND OVERNIGHT AS MOISTURE INCREASES IN SW
FLOW ALOFT. THE REGION WILL ALSO BE NEAR THE RIGHT ENTRANCE
REGION TO THE UPPER LEVEL JET, WHICH SHOULD ALSO ENHANCE ASCENT.
INSTABILITY SHOULD BE MAINLY ELEVATED BY THE TIME CONVECTION
INITIATES, THOUGH THERE IS A BRIEF WINDOW FOR STRONG STORMS
UNTIL THE ELEVATED INSTABILITY AND MARGINAL SHEAR DIMINISHES
LATE THIS EVENING AND OVERNIGHT.
SHOWERS ARE LIKELY TO CONTINUE THROUGH EARLY MORNING, ESPECIALLY
EAST OF A FKL-ZZV LINE, WHERE THE SURFACE FRONT IS EXPECTED TO
SLOW AS A WAVE OF LOW PRESSURE TRACKS NE ALONG IT.
QPF IS EXPECTED TO BE HIGHEST ACROSS THE LAUREL HIGHLANDS AND
NORTHERN WV, WHERE BETTER CONVERGENCE ALONG THE SURFACE FRONT IS
EXPECTED.
SHORT TERM /SATURDAY THROUGH MONDAY/
KEY MESSAGES:
- SCATTERED SHOWERS CONTINUE INTO SATURDAY
- COOLER OVER THE WEEKEND
--------------------------------------------------------------
THE SURFACE COLD FRONT AND INITIAL SHORTWAVE ARE EXPECTED TO
SHIFT SLOWLY EASTWARD ON SATURDAY, AS THE WEAK SURFACE WAVE
CONTINUES NEWD ALONG THE FRONT. SCATTERED TO NUMEROUS SHOWERS
ARE EXPECTED TO CONTINUE, BEFORE TAPERING OFF FROM W-E THROUGH
THE AFTERNOON. GENERALLY DRY WEATHER SHOULD RETURN SATURDAY
NIGHT AS THE FRONT EXITS.
STRATOCU SHOULD DEVELOP ON SUNDAY, ESPECIALLY N OF PITTSBURGH,
AS AN UPPER TROUGH CROSSES THE EASTERN GREAT LAKES AND UPPER
OHIO VALLEY REGION. A WNW BOUNDARY LAYER FLOW OFF OF THE LAKES
COULD ALSO RESULT IN ISOLATED TO SCATTERED SHOWERS N OF I 80 FOR
THE FIRST PART OF SUNDAY. OTHERWISE, MOISTURE APPEARS TOO
SHALLOW FOR ANYTHING OTHER THAN SOME CLOUD COVER AS THE TROUGH
CROSSES.
SURFACE HIGH PRESSURE IS THEN EXPECTED TO BUILD ACROSS THE
REGION SUNDAY NIGHT AND MONDAY, WITH DRY WEATHER AND COOL
TEMPERATURES. SUNDAY NIGHT'S LOWS ARE EXPECTED TO BE 10-15
DEGREES BELOW AVERAGE, WITH MONDAY'S HIGHS AROUND 5 DEGREES
BELOW AVERAGE.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
KEY MESSAGES:
- GRADUAL WARM UP WITH CONTINUED DRY WEATHER THROUGH MID-WEEK.
- TEMPERATURE UNCERTAINTY GROWS LATE-WEEK.
-------------------------------------------------------------------
ALL CLUSTERS, SAVE ONE REPRESENTING 7% OF GUIDANCE, LIFT THE
EASTERN TROUGHING NORTH INTO-QUASI ZONAL FLOW INTO MID WEEK,
WITH OUTLIER ENSEMBLES KEEPING THE TROUGHING SLIGHTLY LONGER.
THIS WILL LIKELY PUT THE 582 DM HEIGHT LINE OVER LAKE ERIE BY
TUESDAY AND ALLOW ENSEMBLE MEAN TEMPERATURES TO GET CLOSE TO
NORMAL BY MID-WEEK.
FROM THIS POINT, UNCERTAINTY INCREASE AS THE BROADNESS OF A
WESTERN RIDGE TRICKLES INTO EASTERN TEMPERATURE UNCERTAINTY. A
BROADER RIDGE MAY STRETCH INTO THE MID-WEST AND KEEP THE
FORECAST AREA CLOSER TO NORMAL, WHILE A MORE NARROW GREAT
PLAINS RIDGE WOULD ALLOW A GREATER DEGREE OF EASTERN TROUGHING
ON THE LEEWARD SIDE. THIS TRICKLES DOWN INTO UNCERTAINTY IN THE
AMPLITUDE OF EASTERN TROUGHING LATE-WEEK, WITH TEMPERATURE
RANGES NEXT FRIDAY ANYWHERE FROM A DEGREE OR TWO ABOVE NORMAL
UNDER BROADER RIDGING AND 10 DEGREES BELOW NORMAL WITH MORE
TROUGHING (25TH-75TH PERCENTILE).
ANY WAY YOU CUT THE CARDS, NOTABLE RAIN WILL BE HARD TO COME BY
WITH NORTHWEST FLOW ALOFT WITH MEDIAN GUIDANCE SHOWING NO QPF
FOR THE WHOLE PERIOD, AND SHOULD WE GET ANY, IT WOULD LIKELY BE
LIMITED. THIS WILL CONTRIBUTE TO PROLONGING DROUGHT ACROSS MUCH
OF THE AREA.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
EXPECT AN INCREASE IN VFR CUMULUS/STRATOCU CLOUDS THIS
AFTERNOON AND EVENING AHEAD OF AN APPROACHING COLD FRONT.
SHOWERS AND POSSIBLE THUNDERSTORMS ARE INITIALLY EXPECTED TO
DEVELOP IN THE VICINITY OF THE FRONT LATE THIS EVENING INTO THE
OVERNIGHT HOURS, WITH LIMITED ELEVATED INSTABILITY IN PLACE.
MAINTAINED PROB30S FOR THIS POTENTIAL GENERALLY FOR AIRPORTS
FROM DUJ-PIT-ZZV AND POINTS EAST, WHERE SLIGHTLY MORE
INSTABILITY IS EXPECTED.
ADDITIONAL SHOWERS AND MVFR RESTRICTIONS ARE MORE LIKELY LATE
TONIGHT AS MOISTURE INCREASES WITH A WEAK WAVE OF LOW PRESSURE
TRACKING NEWD ALONG THE FRONT. MOST OF THIS ACTIVITY IS ALSO
EXPECTED EAST OF A DUJ-PIT-ZZV LINE, WHERE THE FRONT IS EXPECTED
TO SLOW ITS FORWARD PROGRESS. THIS MVFR IS LIKELY TO CONTINUE
INTO SATURDAY MORNING, UNTIL A SLOW IMPROVEMENT TO MAINLY VFR
OCCURS LATE MORNING INTO THE AFTERNOON AS THE FRONT/SURFACE WAVE
SLOWLY EXIT.
OUTLOOK.
A CROSSING UPPER TROUGH COULD RESULT IN CIG RESTRICTIONS AND
ISOLATED SHOWERS N OF PIT ON SUNDAY, OTHERWISE VFR IS THEN
EXPECTED (OTHER THAN ERLY MORNING VLY FG) THROUGH TUESDAY AS
HIGH PRESSURE BUILDS IN.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...WM
NEAR TERM...WM
SHORT TERM...WM
LONG TERM...MILCAREK
AVIATION...WM
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