833
FXUS61 KPBZ 050335
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1135 PM EDT THU SEP 4 2025
SYNOPSIS
FOG EXPECTED OVERNIGHT. ANOTHER FRONT MAY RETURN ISOLATED
THUNDERSTORMS LATE TOMORROW EVENING. COOLER CONDITIONS ARE
EXPECTED OVER THE WEEKEND.
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
KEY MESSAGES:
- FOG EXPECTED THIS MORNING
---------------------------------------------------------------
DENSE FOG POTENTIAL WILL INCREASE OVERNIGHT WITH LIGHT WINDS AT
THE SURFACE AND BOUNDARY LAYER SATURATION. THE MOST LIKELY
AREAS THAT WILL BE IMPACTED BY FOG WILL BE NORTH OF PITTSBURGH
AND IN THE VICINITY OF A STATIONARY FRONT.
SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/
KEY MESSAGES:
- MARGINAL RISK FOR STRONG/SEVERE STORMS WITH PASSAGE OF A
FRONT
- RAIN CHANCES CONTINUE INTO SATURDAY AFTERNOON
--------------------------------------------------------------
THE UPPER LEVEL PATTERN WILL EXPERIENCE A QUICK PIVOT BACK TO
SOUTHWESTERLY FLOW AHEAD OF THE NEXT DEEP SHORTWAVE ROUNDING
THROUGH THE BROADER GREAT LAKES TROUGH. MODEST WARM ADVECTION
AND INITIALLY SUNNIER SKIES ARE LIKELY TO AID TEMPERATURE
RETURNING NEAR THE DAILY AVERAGE HIGH. SUBSIDENCE AHEAD OF THE
APPROACHING MID-LEVEL JET ALSO WILL AID IN FRIDAY INITIALLY
STARTING DRY.
BY LATE FRIDAY EVENING, A NEW COLD FRONT IS EXPECTED TO ADVANCE
INTO THE REGION. JOINT PROBABILITIES OF EFFECTIVE SHEAR
(+30KTS) AND INSTABILITY (500J/KG) IS ELEVATED (ABOVE 70%) AND
COULD PROMPT ORGANIZED STORMS DURING THE TIME PERIOD OF OF 4PM
FRIDAY TO 2AM SATURDAY. SEVERE STORMS COULD PRODUCE DAMAGING
WINDS AND PERHAPS AN ISOLATED TORNADO. STORMS CELLS MOVING DUE
EAST WOULD LIKELY INGEST THE BEST ROTATION UPDRAFTS FOR A
TORNADO THREAT.
THE SEVERE THREAT WILL DECREASE BEFORE DAWN ON SATURDAY.
HOWEVER, REMNANT CONVECTION TOWARDS OUR SOUTHWEST IS EXPECTED TO
TRACK THROUGH THE REGION IN WAVES ON SATURDAY.
THE COMBINATION OF EXCESSIVE CLOUD COVER, RAIN, AND NEAR SURFACE
COLD ADVECTION SATURDAY MEANS AREA HIGH TEMPERATURE MAY BE NEAR
RECORD LOW. SITES THAT WOULD BE WITHIN 3-4 DEGREES FROM TYING OR
BREAKING THE RECORD ARE WHEELING (HLG) AND NEW PHILADELPHIA
(PHD).
LONG TERM /SUNDAY THROUGH THURSDAY/
KEY MESSAGES:
- BELOW AVERAGE TEMPERATURES ARE EXPECTED ON SUNDAY
- A LAKE ENHANCED SHOWER NORTH OF I-80 ARE EXPECTED
- WARMING TREND MONDAY INTO WEDNESDAY
-------------------------------------------------------------------
AS THE AFOREMENTIONED UPPER-LEVEL TROUGH SAGS INTO THE OHIO
RIVER VALLEY SUNDAY, EXPECTED BELOW AVERAGE TEMPERATURES TO
CONTINUE. PREVAILING WESTERLY FLOW OVER THE GREAT LAKES WILL
LIKELY KEEP LAKE ENHANCED SHOWERS NORTH OF I-80.
A GRADUAL WARMING PATTERN IS EXPECTED AS THE UPPER-LEVEL TROUGH
EXITS NORTH AND ZONAL FLOW RETURNS MONDAY INTO TUESDAY.
PROBABILITY OF PRECIPITATION IS CONSIDERED LOW MONDAY INTO
WEDNESDAY WITH BUILDING HIGH PRESSURE TO OUR WEST.
AVIATION /04Z FRIDAY THROUGH TUESDAY/
IFR CONDITIONS WILL BE LARGELY ACROSS THE REGION OVERNIGHT WITH
A COMBINATION OF LOW-LEVEL STRATUS AND PATCHY DENSE FOG AFTER
EARLIER SHOWERS/STORMS HAVE LEFT LOW LEVELS SATURATED UNDER THE
OVERNIGHT INVERSION. LOW CONFIDENCE IN EITHER FOG OR STRATUS AT
ANY GIVEN PLACE GIVEN FORECAST MRI VALUES BEING ON THE FENCE,
BUT IN ANY CASE IFR OR LOWER RESTRICTIONS SHOULD PREVAIL UNTIL
MID- MORNING WITH INCREASED MIXING.
VFR CONDITIONS WILL THEN PERSIST UNTIL ADDITIONAL SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH A CROSSING FRONT PASS THROUGH THE
REGION LATER THIS EVENING AND OVERNIGHT.
THE
OUTLOOK.
VFR IS EXPECTED SATURDAY AFTERNOON THROUGH THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK (OUTSIDE OF SOME RIVER VALLEY MORNING FOG)
WITH HIGH PRESSURE THE DOMINANT FEATURE ACROSS THE REGION.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...HEFFERAN/88
NEAR TERM...HEFFERAN/88
SHORT TERM...HEFFERAN/88
LONG TERM...HEFFERAN
AVIATION...88
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