020
FXUS61 KPBZ 092334
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
734 PM EDT WED SEP 9 2026
WHAT HAS CHANGED
NO MAJOR CHANGES WERE MADE TO THE FORECAST.
KEY MESSAGES
1) STRONG TO SEVERE STORM POTENTIAL LATE THIS EVENING NORTH OF
PITTSBURGH. MARGINAL THREAT FOR LOCALIZED FLASH FLOODING TONIGHT
THROUGH THURSDAY.
2) AN ACTIVE WEATHER PATTERN LOOKS TO CONTINUE INTO EARLY NEXT
WEEK AND WILL WARRANT MONITORING FOR POTENTIAL LOCAL IMPACTS.
DISCUSSION
KEY MESSAGE 1...
NOT MUCH HAS CHANGED SINCE THE PREVIOUS FORECAST CYCLE. HIGH-
RESOLUTION MODELS CONTINUE TO INDICATE A LINE OF STORMS FORMING
LATE THIS EVENING JUST SOUTH OF LAKE ERIE AS AN APPROACHING
TROUGH AND ASSOCIATED COLD FRONT MOVE INTO THE REGION.
THE MOST LIKELY WINDOW REMAINS BETWEEN 7PM TO 9PM ACROSS
NORTHWEST PA AND NORTHEAST OH. A FEW STORMS COULD BE STRONG TO
SEVERE, PARTICULARLY NORTH AND NORTHWEST OF PITTSBURGH, WHERE A
COMBINATION OF MODEST INSTABILITY (900-1200J/KG OF CAPE) AND
EFFECTIVE SHEAR EXCEEDING 30KTS WILL SUPPORT ORGANIZED STORM
MODES (MOST LIKELY IN THE FORM OF BOWING LINE SEGMENTS).
DAMAGING WIND GUSTS WILL LIKELY BE THE PRIMARY THREAT. HOWEVER,
ANY STORMS OR NOTCHES IN THE LINE THAT ARE ABLE TO ACCELERATE
SOUTHEASTWARD COULD ACQUIRE SOME LOW-LEVEL ROTATION BASED ON
MODEL HODOGRAPHS, POTENTIALLY RESULTING IN TRANSIENT LOW-LEVEL
MESOCYCLONE FEATURES CAPABLE OR PRODUCING A FUNNEL CLOUD OR
BRIEF TORNADO.
INSTABILITY IS EXPECTED TO BEGIN WANING AS STORMS MOVE TOWARD
THE PITTSBURGH AREA BETWEEN 9PM AND 11PM, WHICH COULD LIMIT THE
POTENTIAL FOR ADDITIONAL STRONG TO SEVERE STORMS. LIGHTNING
WOULD BE THE PRIMARY THREAT ALONG WITH A MARGINAL LOCALIZED
FLASH FLOOD THREAT DUE TO HEAVY RAINFALL.
THE PROLONGED PASSAGE OF THE TROUGH AND LINGERING STATIONARY
BOUNDARY MAY SUPPORT PERIODS OF MODERATE TO HEAVY RAINFALL
TOTALS DURING THE DAY THURSDAY, POTENTIALLY RESULTING IN
ISOLATED FLOODING ALONG CREEKS AND STREAMS AS WELL AS URBAN AND
LOW-LYING/POOR-DRAINAGE AREAS. THE GREATEST CHANCE FOR THIS
OCCURRING IS ACROSS NORTHERN WV, WHICH WILL BE IN CLOSER
PROXIMITY TO THE SLOWED/STALLED FRONTAL BOUNDARY AND THEREFORE
HAS THE GREATEST POTENTIAL TO SEE MORE PERSISTENT ROUNDS OF
HEAVIER SHOWERS AND THUNDERSTORMS.
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 ACTIVE PATTERN COULD SUPPORT HEAVY RAIN AND/OR
SEVERE WEATHER THREATS EARLY NEXT WEEK AND WILL NEED TO BE
MONITORED.
AVIATION /00Z THURSDAY THROUGH MONDAY/
GENERALLY, STORMS ARE NOT AS WIDESPREAD AS ANTICIPATED, BUT
WHERE THE STRONGEST STORMS ARE, THEY MAY AFFECT BVI, PIT, AGC,
AND LBE OVER THE NEXT COUPLE HOURS, PROGRESSING EAST WITH GUSTS
OF UP TO 40KTS POSSIBLE BEFORE DECAY. SCATTERED SHOWERS MAY
LINGER BEHIND FOR A FEW HOURS, WITH PERHAPS A LOW CHANCE OF
LIGHTNING, BEFORE CHANCES OF MVFR CIGS INCREASE AREAWIDE FROM
02Z TO 06Z.
LOW MVFR IS LIKELY OVERNIGHT, WITH SOME PORTS POTENTIALLY SEEING
HIGH IFR AS CIGS DROP IN LOW MOISTURE. CIG RISES ARE EXPECTED
MID-MORNING TO EARLY AFTERNOON WITH HEATING, WITH THE ONLY PORT
FAVORED TO REMAIN MVFR BEING MGW. SOME AFTERNOON STORMS ARE
AGAIN POSSIBLE, BUT EXPECTED TO BE LESS NUMEROUS THAN THE DAY
PRIOR. THERE WERE TIMED OUT FOR PROB30S FOR NOW.
OUTLOOK...
RESTRICTIONS MAY CONTINUE INTO THURSDAY NIGHT IN SHOWERS/STORMS
UNTIL COLD FRONTAL PASSAGE. 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...CERMAK/HEFFERAN
AVIATION...MILCAREK
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