016
FXUS61 KPBZ 052257
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
657 PM EDT FRI SEP 5 2025
SYNOPSIS
SHOWERS AND THUNDERSTORMS RETURN LATE THIS EVENING INTO TOMORROW
MORNING WITH A CROSSING COLD FRONT. DRY AND COOLER TEMPERATURES
EXPECTED SATURDAY AFTERNOON INTO SUNDAY.
NEAR TERM /THROUGH SATURDAY/
KEY MESSAGES:
- SHOWERS AND ISOLATED STORMS THIS EVENING INTO THE OVERNIGHT
TIME PERIOD; A FEW STORMS COULD BE STRONG TO SEVERE SOUTH OF
PITTSBURGH BEFORE 9PM
- PROBABILITY OF RAIN SHOWERS DECREASES LATE SATURDAY MORNING
- COOLER TEMPERATURES EXPECTED SATURDAY AFTERNOON/NIGHT
---------------------------------------------------------------
A SHORTWAVE TROUGH, AND ITS ASSOCIATED SURFACE COLD FRONT, IS
CURRENTLY TRACKING ACROSS THE REGION THIS EVENING. SHOWERS AND
ISOLATED THUNDERSTORMS ARE ONGOING AHEAD OF THE FRONT. WITH HIGH
SHEAR AND LOW CAPE POTENTIAL (+40KTS/500/KG) THE CONCERN FOR THE
EVENING WOULD BE DAMAGING WIND GUSTS OR AND ISOLATED TORNADO
WITH ANY DEVELOPING STORM. AREAS NORTH OF I-70 HAVE VERY HIGH
EFFECTIVE SHEAR (50-65KTS) AND UPDRAFTS MAY BE QUICKLY CUT-OFF
AND DISSOLVE DURING THE EARLY STAGE OF FORMATION. THE POTENTIAL
OF SEVERE STORMS DECREASES BETWEEN 9PM TO 11PM.
SHOWERS ARE LIKELY TO CONTINUE THROUGH EARLY MORNING WITH THE
SLOW PROGRESSION OF THE FRONT.
QPF FOR THE NEXT 12 HOURS IS EXPECTED TO BE HIGHEST ACROSS THE
LAUREL HIGHLANDS AND NORTHERN WV, WHERE BETTER CONVERGENCE ALONG
THE SURFACE FRONT IS EXPECTED.
SHORT TERM /SATURDAY NIGHT 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 /00Z SATURDAY THROUGH WEDNESDAY/
SHOWERS AND THUNDERSTORMS ARE CURRENTLY DEVELOPING ALONG A COLD
FRONT THIS EVENING. MGW IS LIKELY THE ONLY TERMINAL THAT COULD
BE IMPACTED BY A STORM OR SHOWER IN THE NEXT 3 HOURS.
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...HEFFERAN
NEAR TERM...HEFFERAN
SHORT TERM...WM
LONG TERM...MILCAREK
AVIATION...WM/HEFFERAN
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