458
FXUS61 KPBZ 131642
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1242 PM EDT WED MAY 13 2026
WHAT HAS CHANGED
A SLIGHT UPWARD ADJUSTMENT OF PRECIPITATION CHANCES AND RAIN
AMOUNTS TOMORROW, ACCOMPANIED BY A SLIGHT DOWNWARD ADJUSTMENT
OF TEMPERATURES NEXT WEEK.
KEY MESSAGES
1) A 1 OUT OF 5 SEVERE RISK REMAINS THIS AFTERNOON, WITH THE
PRIMARY THREAT BEING DAMAGING WINDS.
2) COOL TEMPERATURES THURSDAY REBOUND TO HOT TEMPERATURES TO
START NEXT WEEK, WITH INCREASED HEAT RISK.
DISCUSSION
KEY MESSAGE 1...
THE MARGINAL (OR 1 OUT OF 5) SEVERE RISK THIS AFTERNOON IS STILL
IN PLAY. AS CLOUDS DEPART TO THE EAST TODAY, A NARROW WARM
SECTORS WILL REMAIN POSITIONED OVER THE AREA ALLOW FOR
INSTABILITY GENERATION WITH MOSTLY CLEAR SKIES AHEAD OF A COLD
FRONT. AS THE COLD FRONT APPROACHES, IT WILL ACT AS THE FORCING
FOR INITIATION. CONFIDENCE IN THE EXISTENCE OF STORMS TODAY IS
HIGH ALONG THE FRONT FOR WESTERN PA / NORTHERN WV, BUT THE
PROBABILITY OF A SEVERE ENVIRONMENT IS LOWER.
SPC MESOANALYSIS AND OBSERVATIONS AGREE IN THE ABILITY TO
DEVELOP 500 TO 1000 J/KG MLCAPE (1000 TO 1500 J/KG SBCAPE)
WITHIN THE WARM SECTOR. THIS IS ALREADY ABOVE THE 13Z NBMS 75TH
PERCENTILE. THERE IS ALSO HIGH ENOUGH CONFIDENCE TO DEVELOP
>30KTS OF BULK SHEAR, WITH PERHAPS AS MUCH AS 40KTS FOR NORTHERN
WV. THAT BEING SAID, ORGANIZED CONVECTION IS BECOMING
INCREASINGLY LIKELY. DCAPE IS CORRESPONDINGLY ABOUT 500 TO 700. THE
MAIN UNCERTAINTY IN STRONG STORMS WILL BE DRY AIR ALOFT. MOST
CAMS HAVE DEW POINT DEPRESSIONS INCREASING ABOVE THE 800 TO
700MB LAYER. WHILE THIS WOULD CONDITIONALLY HEIGHTEN WET-
BULBING POTENTIAL, DCAPE, AND HAIL GROWTH POTENTIAL, THE MAIN
CONCERNS IS THAT THERE WILL NOT BE ENOUGH SBCAPE TO WET- BULB A
PARCEL THROUGH A DEEP DRY AIR LAYER ALOFT. IF STORMS DO WET-
BULB AND GET TALLER, SEVERE THREAT WOULD BE HIGHER AS THEY
BECOME MORE UNSTABLE, WHICH POSITIVELY FEEDS BACK TO DCAPE AND
WIND/HAIL POTENTIAL.
THE MOST LIKELY TIMING AND AREA FOR ANY SEVERE THREAT IS
NORTHERN WV AND WESTERN PA, VAGUELY BETWEEN 1PM AND 7PM. THE
COLD FRONT WILL PROGRESS FROM WEST TO EAST, AND SO WILL THE
THREATS ALONG IT.
KEY MESSAGE 2...
THURSDAY WILL BE DEFINED BY COLD TEMPERATURES, AS THE COLD-CORE
OF AN UPPER TROUGH MOVES OVERHEAD. THIS WILL ALSO ALLOW FOR
SHOWER DEVELOPMENT INTO THE DAY. OVERNIGHT, CLEARING IS FAVORED
WITH LIMITED FROST POTENTIAL.
STARTING FRIDAY AND RUNNING THROUGH THE BEGINNING OF NEXT WEEK,
UPPER RIDGING WILL ENSUE. TEMPERATURES WILL CLIMB AROUND 15
DEGREES ABOVE AVERAGE TO START NEXT WEEK. THIS WILL BRING WITH
IT SOME HEAT RISK, WITH MOST AREAS SEEING MODERATE HEAT RISK FOR
SUNDAY THROUGH TUESDAY. THERE'S STILL A BIT OF UNCERTAINTY IN
TEMPERATURES. THE NBM DETERMINISTIC PUNCHES ABOVE ITS WEIGHT FOR
BECAUSE OF COLD-SEASON BIAS CORRECTION, WHILE MUCH OF THE RAW
ENSEMBLE GUIDANCE SHOWS TEMPERATURES TOPPING OUT IN THE MID-TO-
UPPER 80S, WITH PERHAPS A HIGH END OF LOW 90S FOR TUESDAY.
BECAUSE OF THIS, IN COORDINATION WITH WPC, TEMPERATURES WILL BE
"LOWERED" TO START NEXT WEEK, BUT STILL REMAINING QUITE WARM.
AS WE OFTEN HAVE TO WORRY ABOUT WITH HEAT, WE WILL ALSO BE
KEEPING AN EYE ON SEVERE WEATHER CHANCES. WITH THE RIDGE
BUILDING IN SATURDAY, WE WILL HAVE TO MONITOR RIDGE-RIDING
CONVECTION, WITH CIPS ALREADY SHOWING 15% CONTOUR FOR SEVERE,
WITH CSU ML SHOWING A 5% CONTOUR. NON-ZERO CHANCES PERSIST
THEREAFTER IN DOWNBURST POTENTIAL UNDER THE RIDGE AND UPSTREAM
CONVECTION IN NW FLOW ALOFT.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
ALONG A PASSING COLD FRONT, CHANCE FOR SHOWERS AND THUNDERSTORMS
WILL INCREASE THIS AFTERNOON ACROSS THE AREA, SAVE ZZV WHERE THE
FRONT HAS ALREADY PASSED. WITH CLEARING THIS MORNING, ENOUGH
HEATING TO HAS MATERIALIZED TO GENERATE SOME STRONG TO SEVERE
THUNDERSTORMS POSSIBLY ORGANIZING INTO A LINE OR BROKEN LINE AS
THEY MOVE ACROSS THE AREA. DEVELOPMENT IS FAVORED AFTER 18Z AND
PROGRESSING SOUTHEASTWARD INTO THE EVENING. HAVE INCLUDED TEMPO
GROUPS AND ASSOCIATED PERIODIC RESTRICTIONS IN THUNDERSTORMS IN
THE MOST LIKELY TIMEFRAME. STRONG WIND GUSTS ARE THE PRIMARY
THREAT WHICH HAS BEEN NOTED IN TEMPO GROUPS BASED ON CONVECTION
IN UPSTREAM OBS, BUT SMALL HAIL IS POSSIBLE AS WELL.
THUNDERSTORMS DEPART TO THE EAST AS A COLD FRONT SWEEPS THROUGH
THE AREA THIS EVENING BRINGING A WIND SHIFT FROM SOUTHWEST TO
NORTHWEST. MORE WIDESPREAD RESTRICTIONS SETTLE IN BEHIND THE
FRONT OVERNIGHT MOST LIKELY IN THE FORM OF MVFR/IFR CIGS
(HIGHEST IFR PROBABILITY FOR FKL/DUJ) AS WIND REMAINS ELEVATED.
LOW, BUT NOT ZERO IFR PROBABILITY EXTENDS AS FAR SOUTH AS PIT
THOUGH HI RES SOUNDINGS AREN'T NEAR AS AGGRESSIVE, SO ERRED WITH
LOW-END MVFR OUTSIDE OF FKL/DUJ. WITH WEAK LIFT BENEATH A COLD
CORE UPPER LOW OVERHEAD AND A CONDITIONALLY UNSTABLE, SATURATED
NEAR-SURFACE PROFILE, MVFR CIGS, DRIZZLE, AND LIGHT SHOWERS ARE
LIKELY TO PERSIST INTO AT LEAST THE MORNING HOURS ON THURSDAY.
WITH MIXING, CIGS SHOULD GRADUALLY RISE, BUT WE'LL LIKELY
STRUGGLE TO RID OURSELVES OF THE RESTRICTIONS UNTIL LATER IN
THE AFTERNOON. WIND GUSTS WILL PICK UP TO AROUND 20 KNOTS BY
LATE MORNING OUR OF THE WEST-NORTHWEST.
OUTLOOK...
RESTRICTIONS CONTINUE INTO THURSDAY MORNING BEFORE GRADUAL
IMPROVEMENT BY THE EVENING HOURS WHEN VFR RETURNS THROUGH FRIDAY
BENEATH SURFACE HIGH PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...MILCAREK
AVIATION...MLB
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