064
FXUS61 KPBZ 032346
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
746 PM EDT THU SEP 3 2026
WHAT HAS CHANGED
SEVERE THUNDERSTORM WATCH ISSUED FOR OUR ENTIRE AREA THROUGH
10PM. INTRODUCTION OF AN ENHANCED RISK (LEVEL 3/5) FOR SEVERE
THUNDERSTORMS ON THURSDAY.
KEY MESSAGES
1) ROUNDS OF SHOWERS AND STORMS CONTINUE THROUGH FRIDAY NIGHT WITH
ASSOCIATED SEVERE WEATHER THREATS.
2) UNSEASONABLY WARM CONDITIONS ALSO CONTINUE. HEAT ADVISORIES
REMAIN IN EFFECT FOR MOST OF OUR AREA THROUGH THURSDAY.
DISCUSSION
KEY MESSAGE 1...
STRONG 594 DAM RIDGING REMAINS CENTERED ACROSS THE SOUTHEAST
WITH THE AXIS OF THE RIDGE EXTENDED NORTH THROUGH THE PLAINS.
LOCALLY, WE'RE PARKED BENEATH NORTHWEST MID-LEVEL FLOW, AND
SUBTLE IMPULSES IN THE FLOW COMBINED WITH MESOSCALE SURFACE
FEATURES WILL CONTINUE TO BE THE DRIVER OF OUR THUNDERSTORM
COMPLEXES OVER THE NEXT 24-36 HOURS.
LINGERING SHOWERS AND DEBRIS CLOUD COVERAGE FROM THURSDAY MORNING'S
CONVECTION WILL CLEAR OUT BY EARLY AFTERNOON, AND SATELLITE IMAGERY
SHOWS CLEAR SKIES ARRIVING IN THE WAKE. THIS SHOULD ALLOW FOR QUICK,
EFFICIENT HEATING AND DIURNAL CU DEVELOPMENT WHILE THE ATMOSPHERE
RECOVERS. WHAT WE THEN TURN OUR ATTENTION TO IS A DEVELOPING
THUNDERSTORM COMPLEX OVER LOWER MICHIGAN THAT 12Z CAMS ALL DIVE
SOUTHEAST AND INTO NORTHWEST PA AFTER 3-4PM. SOME SUGGEST THAT THERE
COULD BE A FEW DISCRETE CELLS POPPING OUT AHEAD OF THE COMPLEX IN
WESTERN PA AROUND THAT SAME TIME. THESE SHOULD HAVE A RATHER POTENT
ENVIRONMENT TO WORK WITH AS EXPLORATION OF POINT SOUNDINGS
ACROSS THE AREA SHOWS 2500-3000 J/KG OF MLCAPE, 35-40 KNOTS OF
EFFECTIVE SHEAR, AND STEEP MID-LEVLE LAPSE RATES EXCEEDING 7
C/KM. ONE DIFFERENCE FROM WEDNESDAY IS THAT THERE APPEARS TO BE
A BIT LESS MID- LEVEL DRY AIR WHICH COULD SUPPORT BETTER STORM
ORGANIZATION AND INTENSITY TODAY. ALL HAZARDS WILL BE ON THE
TABLE WITH BOTH MODES; INITIAL DISCRETE CELLS COULD BECOME
SUPERCELLULAR AND POSE A WIND, HAIL, AND TORNADO THREAT,
ESPECIALLY IF DEW POINTS DON'T MIX OUT IN TIME AND WE'RE LEFT
WITH LOW TO MID 70S AS NOTED BY THE USUALLY DRIER HRRR. DAMAGING
WIND WILL BE THE PRIMARY THREAT WITH THE MORE LINEAR MODE, BUT
CAN'T IGNORE 0-3 KM SHEAR VALUES NEARING 30 KNOTS AND THE
POTENTIAL EXISTING FOR A QUICK QLCS TORNADO SPIN UP. AGAIN,
THINK MOST LIKELY TIMING IS INTO NW PA AROUND 4-5PM AND
PITTSBURGH METRO AROUND 6-7PM. A LOCALIZED ENHANCED RISK HAS
BEEN INTRODUCED FOR THE HEIGHTENED WIND THREAT FROM PITTSBURGH
NORTH. IN ADDITION, WITH REPEATED ROUNDS OF RAIN THE PAST 24-36
HOURS, FLASH FLOODING WILL ALSO POSE A THREAT AS FLASH FLOOD
GUIDANCE VALUES ALONG I-80 SIT AROUND 1-1.25" IN ONE HOUR. THAT
MAY BE ACHIEVED RATHER EASILY THIS AFTERNOON WITH A STORM OR TWO
IN THE SAME AREA. FOR THAT REASON, HAVE ISSUED A FLOOD WATCH
THROUGH TONIGHT NORTH OF PITTSBURGH.
COME FRIDAY, SOME CAMS SUGGEST ANOTHER EARLY MORNING PUSH OF SHOWERS
AND STORMS ALBEIT WITH LESS INTENSITY. FINER DETAILS ON THAT SHOULD
ARISE LATER TODAY WHEN WE SEE THE INITIATION OF IT OFF TO OUR
NORTHWEST. LATER FRIDAY, WE'LL YET AGAIN FACE ANOTHER MCS THREAT
WITH A CLUSTER DEVELOPING WAY OFF TO OUR NORTH IN MINNESOTA AND
DIVING ITS WAY THROUGH THE GREAT LAKES INTO OUR NECK OF THE WOODS.
EXACT TRACK AND TIMING OF IT IS EVEN MORE UNCERTAIN AS ITS SEVERAL
DOMINO PIECES AWAY FROM WHERE WERE AT CURRENTLY, AND MORNING
CONVECTION WILL HAVE A SAY IN AFTERNOON INTENSITY AS WELL. THE FRONT
ITSELF SHOULD THEN PASS THROUGH DURING THE LATE AFTERNOON ON FRIDAY
USHERING IN A DRIER AIRMASS AS SURFACE HIGH PRESSURE ARRIVES FROM
THE NORTH, THOUGH MANY OF THE 12Z CAMS NOW THINK WE HAVE YET ANOTHER
CAR IN THE MCS TRAIN RIDING THE SOUTHEASTERN PERIPHERY OF THE
SURFACE HIGH AND PERHAPS IMPACTING US AGAIN OVERNIGHT FRIDAY NIGHT.
NOT PUTTING A TON OF STOCK IN THIS POSSIBILITY YET, BUT IT'S
INTRIGUING THAT A COUPLE MODELS ARE COMING TO A SIMILAR SOLUTION.
KEY MESSAGE 2...
ASIDE FROM THE STORMS, UNSEASONABLY WARM CONDITIONS CONTINUE
THROUGH THURSDAY. HEAT RISK WILL REMAIN IN THE MAJOR CATEGORY
WITH POCKETS OF EXTREME IN THE VALLEYS AND URBAN AREAS WHERE
TEMPERATURES REACH THE LOW TO MID 90S AND DEW POINTS IN THE 70S
RESULTING IN HEAT INDICES EXCEEDING 100F. SOME LOCALIZED COOLER
AREAS ARE POSSIBLE UNDERNEATH INCREASED CLOUD COVER FORM EARLY
MORNING STORMS, BUT STILL EXPECT THAT WE'LL BE ABLE TO RECOVER
AND HEAT WELL.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
EXPECT SOME IFR AND BELOW RESTRICTIONS AS A COUPLE ROUNDS OF
SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE THROUGH THE AREA.
THIS WILL CONTINUE THROUGH AT LEAST 04Z AT MOST TERMINALS. THE
SEVERE THREAT WILL BEGIN TO WANE BUT THERE STILL MAY BE SOME 30
KNOT GUSTS AT TIMES THROUGH THE EVENING. THE ZZV AND MGW
TERMINALS STAND TO BE IMPACTED BY DEVELOPING THUNDERSTORMS
LATER IN THE EVENING. THIS WILL BE IN THE 02Z TO 05Z TIMEFRAME
AND SOME IFR CONDITIONS ARE POSSIBLE. MUCH OF THE CONVECTION IS
EXPECTED TO BE WEAKENED AND MOVING OUT BY 06Z.
THE 06Z TO 14Z TIMEFRAME WILL BE THE PERIOD FOR ANY FOG AND LOW
STRATUS DEVELOPMENT. HAVE KEPT THE POTENTIAL FOR THAT IN THE
TAFS FOR THE NORTHERN TERMINALS.
HEADING INTO THE DAY TOMORROW, ANOTHER MCS IS EXPECTED TO
POTENTIALLY MOVE THROUGH THE AREA. HAVE USED A FEW PROB30S IN
THE 16Z TO 22Z TIMEFRAME FOR RESTRICTIONS GETTING BELOW IFR IN
MOST CASES. WINDS THROUGH THE PERIOD ARE EXPECTED TO BE LIGHT
AND VARIABLE EXPECT FOR AREAS NEAR THUNDERSTORMS.
OUTLOOK...
RESTRICTIONS ARE POSSIBLE INTO FRIDAY NIGHT AS ANOTHER MESOSCALE
CONVECTIVE COMPLEX HAS THE CHANCE OF MOVING THROUGH. THIS WILL
PROVIDE SOME ADDITIONAL RESTRICTIONS IN ADDITION TO ANY FOG
DEVELOPING.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ007>009-015-016.
OH...NONE.
WV...NONE.
DISCUSSION...MLB
AVIATION...CL/SHALLENBERGER
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