264
FXUS61 KPBZ 161134
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
734 AM EDT WED SEP 16 2026
WHAT HAS CHANGED
UPDATE TO AVIATION DISCUSSION.
KEY MESSAGES
1) SHOWER AND THUNDERSTORM CHANCES LINGER TODAY AND TOMORROW
WITH A LOW RISK OF LOCALIZED FLOODING AND A NON- ZERO CHANCE OF
SEVERE WEATHER.
2) UNSETTLED WEATHER RETURNS LATE SATURDAY INTO NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...
IN LINE WITH THE PRIOR FORECAST UPDATE, THIS ONE MAINTAINS THE
EARLIER ARRIVAL TIME OF A COLD FRONT, SWEEPING DOWN ACROSS THE
AREA THIS AFTERNOON AND EVENING, BEFORE STALLING TONIGHT.
PROVIDED THAT SOUTHWESTERLY SURFACE FLOW THROUGH MUCH OF THE
DAY WILL KEEP DEW POINTS >70F WITH 60% TO 90% CONFIDENCE AND
TEMPERATURES CLIMBING INTO THE MID TO UPPER 80S, THE
THERMODYNAMIC SETUP WILL FEEL MORE LIKE SUMMER THAN FALL. ASCENT
ALOFT SEEMS TO BE SUBTLE DURING THE DAY, WHICH MIGHT HINT TO
CONVECTIVE CHANCES BEING MOSTLY TIED TO THE FRONT ITSELF (NORTH
OF I-70), THOUGH WARM AND MOIST CONDITIONS WITH 500-1500 J/KG
SBCAPE (25TH-75TH PERCENTILE), AND BROAD ASCENT MEAN POP UP
STORMS COULD THEORETICALLY DEVELOP ANYWHERE. SFC-6KM SHEAR IS
FAIRLY WEAK, THOUGH MOST OF THIS IS PACKED INTO THE SFC-2KM
LAYER, MEANING A SPIN UP COULDN'T BE RULED OUT. THAT BEING SAID,
MOST OF THIS IS STRAIGHT-LINE AND WESTERLY, SO ANY ROTATION
WOULD BE DEPENDENT ON A RIGHT MOVING (SOUTHEAST MOVING) CELL.
DCAPE WILL BE MORE MARGINAL, WITH 500-700 J/KG FORECAST, MOST
RELIANT ON DEEP VERTICAL DEVELOPMENT TO REALIZE GUSTY WIND
POTENTIAL. ML OUTLOOKS ARE NOT VERY BULLISH AT ON ON SEVERE
POTENTIAL, WITH BOTH RIGHT MOVERS AND DEEP STORMS GENERALLY
UNLIKELY, BUT THE SEVERE RISK IS NON-ZERO NONETHELESS. WHAT MAY
BE MORE LIKELY IS LOCALIZED FLOOD IN THE EVENT OF ANY TRAINING
THAT MIGHT OCCUR (PARTICULARLY FOR URBANIZED CORRIDORS), WITH
PWATS PUSHING 1.8-2.0 INCHES (ABOVE THE DAILY RECORD) AND WARM
RAINFALL PROCESSES LEADING TO EFFICIENT, HEAVY RAINFALL IN AND
STORMS THAT DO DEVELOP.
00Z MODELS HAVE BEEN MORE CONSISTENT WITH A SECOND ROUND OF
STORMS DEVELOPING UPSTREAM EARLY THURSDAY MORNING, AS A MID-
LEVEL SHORTWAVE ACCELERATES LOW LEVEL FLOW ABOVE THE NOCTURNAL
INVERSION. SFC-3KM SHEAR MAY INCREASE TO 20-30KTS, WITH >90%
CHANCE OF NON-ZERO MUCAPE WITH THE 90TH PERCENTILE AS HIGH AS
1000 J/KG. CONVECTIVE CHANCES HAVE INCREASED, BUT TIMING STILL
REMAINS UNCERTAIN. MOST ENSEMBLES HAVE THESE STORMS PROGRESSING
INTO THE AREA AROUND 6AM THURSDAY, BUT OUTLIERS (NAM), SHOW
DEVELOPMENT POTENTIAL AS EARLY AS MIDNIGHT. SHOULD THIS OCCUR,
SEVERE RISK WILL BE LOW WITH DECOUPLING, BUT PWATS WILL REMAIN
ABOVE RECORD LEVELS (1.9-2.1 INCHES), SO LOCALIZED FLASH FLOOD
POTENTIAL LINGERS FOR TRAINING STORMS OR AREAS ALREADY HIT FROM
THE DAY PRIOR. IN THE SLOWEST SCENARIOS FOR THIS PASSAGE, A VERY
LOW SEVERE RISK (WEAK SPIN UP / WINDS) LINGERS FOR WEST PA /
NORTH WV EARLY THURSDAY SHOULD THE ATMOSPHERE DECOUPLE LATE
MORNING. COVERAGE DURING THE AFTERNOON THURSDAY HAS TRENDED DOWN
BEHIND THIS MORNING WAVE, BUT STILL NON-ZERO STORM CHANCES
LINGER FOR THE DAY (THOUGH SEVERE AND FLOOD RISKS MAY BE LOWER
THAN THE PRIOR UPDATE). STORM COVERAGE FRIDAY HAS ALSO TRENDED
LOWER WITH THE ONLY CHANCE OF RAIN/STORMS SOUTH OF I-70 IN THE
EVENT THE FRONT HASN'T FULLY CLEARED YET.
KEY MESSAGE 2...
A PARADE OF SHORTWAVES IN WNW FLOW ALOFT ALLUDE TO MORE CHANCES
OF RAIN AND THUNDER BY THE WEEKEND. CONFIDENCE REMAINS HIGHEST
LATE SATURDAY INTO MONDAY (75% CHANCE OF RAIN). THIS WILL CARRY
MORE LOW-END SEVERE/FLOOD RISKS.
THE PATTERN BY THE MIDDLE OF NEXT WEEK REMAINS UNCERTAIN, WITH
ONE CAMP OF ENSEMBLES REMAINING UNSETTLED AND SEASONABLE, IN A
PATTERN SIMILAR TO THAT OF THIS WEEKEND. ANOTHER CAMP BRING A
COLD FRONT THROUGH, WITH COOLER AND DRIER CONDITIONS.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
CONFIDENCE REMAINS HIGH IN VFR THROUGH AT LEAST 22Z UNDER A LOW
VFR CU DECK, WITH THE EXCEPTION BEING THE OCCURRENCE OF ANY LOW
PROBABILITY (30%) SHOWERS AND STORMS THROUGHOUT THE DAY THAT
COULD BRING BRIEF REDUCTIONS IN CIGS/VIS. THUNDERSTORMS ARE MOST
LIKELY TO REMAIN WIDELY SCATTERED, GENERALLY PROGRESSING FROM
NORTHWEST TO SOUTHEAST THIS MORNING TO ~02Z THIS EVENING.
OVERNIGHT, MVFR CIG DECKS MAY PROGRESS OVER THE AREA FROM NORTH
TO SOUTH BUT COVERAGE IS LIKELY TO DEPEND ON HOW MAY AREAS SEE
RAIN DURING THE DAY. LATEST GUIDANCE SUGGESTS THIS LOW CIG DECK
MAKES IT AS FAR SOUTH AS ROUGHLY THE I-70 CORRIDOR BY DAYBREAK
THURSDAY. THERE IS ALSO INCREASING PROBABILITIES FOR PERIODS OF
IFR CEILINGS AT FKL/DUJ MAINLY AFTER 06Z.
OUTLOOK...
ANOTHER WAVE OF SHOWERS AND STORMS IS EXPECTED THURSDAY
MORNING, WITH MORE CHANCES FOR TEMPORARY REDUCTIONS IN CIGS/VIS.
CONVECTIVE COVERAGE IS LIKELY TO REMAIN SCATTERED INTO THURSDAY
AFTERNOON/EVENING. IMPROVEMENT TO VFR IS LIKELY FRIDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...MILCAREK
AVIATION...CERMAK/MILCAREK
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