656
FXUS61 KPBZ 091153
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
753 AM EDT WED SEP 9 2026
WHAT HAS CHANGED
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
1) STRONG TO SEVERE STORM POTENTIAL LATE THIS EVENING NORTH OF
PITTSBURGH
2) AN ACTIVE WEATHER PATTERN COULD OCCUR EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...
HIGH-RESOLUTION MODELS CONTINUE TO INDICATE THAT SHOWER AND
THUNDERSTORM ACTIVITY WILL INCREASE LATE THIS EVENING JUST SOUTH
OF LAKE ERIE AS AN APPROACHING TROUGH AND ITS ASSOCIATED COLD
FRONT MOVE INTO THE REGION.
THE MOST LIKELY WINDOW FOR STORMS TO DEVELOP WOULD BE BETWEEN
7PM TO 9PM NEAR I-80. A FEW STORMS COULD BE STRONG TO SEVERE,
PARTICULARLY NORTH OF PITTSBURGH, WHERE A COMBINATION OF MODEST
INSTABILITY (900-1200J/KG OF CAPE) AND EFFECTIVE SHEAR EXCEEDING
30KTS WILL SUPPORT ORGANIZED CONVECTION. DAMAGING WIND GUST WILL
LIKELY BE THE PRIMARY THREAT. HOWEVER, A STORM THAT ACCELERATES
SOUTHEASTWARD COULD ACQUIRE SOME LOW-LEVEL ROTATION, POTENTIALLY
RESULTING IN A FUNNEL CLOUD OR BRIEF TORNADO.
AS STORMS MOVE TOWARD THE PITTSBURGH AREA BETWEEN 9PM AND 11PM,
INSTABILITY IS EXPECTED TO DECREASE, WHICH COULD LIMIT THE
POTENTIAL FOR ADDITIONAL STRONG TO SEVERE STORMS. LIGHTNING
WOULD BE THE PRIMARY THREAT ALONG WITH LOCALIZED HEAVY RAINFALL.
THE PROLONGED PASSAGE OF THE TROUGH AND LINGERING STATIONARY
BOUNDARY MAY SUPPORT PERIODS OF MODERATE TO HEAVY RAINFALL
TOTALS ON THURSDAY, POTENTIALLY RESULTING IN ISOLATED FLOODING
NEAR CREEKS AND STREAMS.
DRIER CONDITIONS ARE EXPECTED FRIDAY UNDER HIGH PRESSURE.
KEY MESSAGE 2...
MACHINE-LEARNING MODELS SUGGEST THAT AFTER A BRIEF PERIOD OF
RIDGING ON FRIDAY, OUR LARGE-SCALE WEATHER PATTERN WILL
TRANSITION TO A MORE ZONAL FLOW. AS A RESULT, THIS WILL ALLOW
DISTURBANCES FORMING UPSTREAM (TO OUR WEST) TO TRACK INTO OUR
AREA. THIS PATTERN COULD CREATE A HEAVY RAIN THREAT AND/OR A
SEVERE WEATHER THREAT EARLY NEXT WEEK AND WILL NEED TO BE
MONITORED.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
VFR CONDITIONS ARE FORECAST FOR MUCH OF THE DAY AS HIGH PRESSURE
DEPARTS. SCATTERED CUMULUS ARE FORECAST TO DEVELOP UNDER MID AND
UPPER CLOUDS, THE HEIGHTS OF WHICH WILL SLOWLY FALL THROUGH THE
AFTERNOON. A STRAY SHOWER OR TWO REMAINS POSSIBLE, MAINLY NORTH
OF PIT, BUT CHANCES ARE TOO LOW FOR EVEN PROB30 GROUPS RIGHT
NOW. A TIGHTENING PRESSURE GRADIENT AND RETURN FLOW BEHIND THE
DEPARTING HIGH WILL HELP TO KICK UP SOUTHWEST WIND GUSTS OF 15
TO 25 KNOTS THIS AFTERNOON.
A PASSING TROUGH AND ITS ASSOCIATED COLD FRONT WILL BEGIN TO
APPROACH FROM THE NW LATE TODAY, MAINLY AFTER 23Z. SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP SOUTH OF LAKE ERIE
BETWEEN 22Z TO 00Z AND ADVANCE SOUTH INTO EARLY THURSDAY
MORNING. SOME MODELS ARE WAVERING A BIT ON PRECIPITATION
COVERAGE DURING THE INITIAL TROUGH PASSAGE, BUT AVAILABLE
MOISTURE AND SUPPORT FOR LIFT SUGGEST CONTINUING TO EXPECT AT
LEAST A BROKEN LINE OF SHOWERS AND STORMS. FOUR HOUR TEMPO
GROUPS CONTINUE TO BE USED. PAST THE MAIN LINE, ALONG WITH A
FEW LINGERING SHOWERS, CEILINGS SHOULD DROP TO MVFR/IFR IN
ABUNDANT LOW-LEVEL MOISTURE.
OUTLOOK...
RESTRICTIONS, CONSISTING OF MVFR TO IFR CEILINGS AND PERHAPS
ADDITIONAL SHOWERS, MAY CONTINUE INTO THURSDAY AFTERNOON. VFR
SHOULD RETURN FRIDAY BEFORE ANOTHER SHORTWAVE TROUGH RETURNS
SHOWER CHANCES SATURDAY AND SUNDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...HEFFERAN
AVIATION...CL/HEFFERAN
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