127
FXUS61 KPBZ 202348
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
748 PM EDT FRI MAR 20 2026
WHAT HAS CHANGED
SEVERE STORM POTENTIAL HAS TRENDED DOWN A BIT FOR THIS EVENING
WITH THE DAYTIME RAIN AND CLOUDS HINDERING DESTABILIZATION.
GIVEN STRONG HEATING AND FAVORABLE DYNAMICS SUNDAY, A SMALL
UPTICK IN STRONG STORM POTENTIAL IS NOTED, AND SPC HAS EXPANDED
THE SLIGHT RISK INTO SOUTHWESTERN PENNSYLVANIA.
KEY MESSAGES
1) LOW POTENTIAL FOR STRONG TO SEVERE STORMS FRIDAY EVENING,
WITH HAIL APPEARING TO BE THE PRIMARY THREAT.
2) SOMEWHAT BETTER STORM POTENTIAL ON SUNDAY, WITH ALL SEVERE
THREATS IN PLAY.
DISCUSSION
KEY MESSAGE 1...
AN AREA OF STRATIFORM RAIN AND THICK CLOUD COVERAGE WITH LIFT
UNDER THE FAVORABLE UPPER JET EXIT REGION HAS CONTINUED TO
PLAGUE THE AREA INTO EARLY THIS EVENING. THE BACK EDGE OF THE
RAIN WILL MOVE NORTH TO SOUTH ACROSS THE AREA LIKELY CLEARING BY
8PM OR SO. QUICKLY ON THE HEELS OF THAT RAIN IS A COLD FRONT
FOLLOWING A SIMILAR PATH.
DESTABILIZATION THROUGH THE DAY WAS GREATLY INHIBITED BY THE
AFOREMENTIONED FACTORS, BUT THAT SAID, THE POST-FRONTAL
ENVIRONMENT COULD SUPPORT A LOW-END RISK FOR HAIL WITH ANY
STORMS AFTER 8PM OR SO. STEEPENING MID-LEVEL LAPSE RATES WITH
COLDER AIR FILTERING IN BEHIND THE FRONT, APPROACHING THE 7-8
C/KM RANGE, MAY SUPPORT SOME ELEVATED INSTABILITY (LATEST CAMS
SUGGESTING MUCAPE VALUES OF AROUND 500-800 J/KG). COMBINED WITH
0-6 KM SHEAR STILL BETWEEN 40 AND 50 KNOTS, ANY SUCCESSFUL
CONVECTION COULD HAVE SUFFICIENT UPDRAFT/DOWNDRAFT SEPARATION
FOR MARGINALLY SEVERE HAIL IN THE STRONGEST CELLS. THE BIG
QUESTION IS *IF* STORMS OCCUR AS A POST-FRONTAL ENVIRONMENT
TYPICALLY ISN'T WHERE YOU'D EXPECT DEVELOPMENT. BY THIS POINT,
SOUNDINGS ARE GENERALLY IN GOOD AGREEMENT THAT THE SURFACE IS
STABLE, OR AT WORST ISOTHERMAL, SO A DAMAGING WIND AND TORNADO
THREAT APPEARS TO BE ON THE VERY LOW SIDE.
QPF TOTALS THROUGH TONIGHT TOP OUT IN THE 0.25 TO 0.50 INCH
RANGE, WITH THE HIGHER TOTALS LIKELY IN THE RIDGES AS SUPPORTED
BY HI-RES MODEL DATA. OF COURSE, LOCALLY HIGHER TOTALS COULD BE
POSSIBLE IN ANY HEAVIER STORMS. ANY SHOWERS/STORMS SHOULD
LARGELY PULL SOUTH OF THE REGION BY 06Z WITH THE DEPARTING
BOUNDARY.
KEY MESSAGE 2...
AFTER A QUIET SATURDAY, A SOMEWHAT MORE ROBUST THREAT FOR
SEVERE WEATHER IS PRESENT FOR SUNDAY. WARM FRONTAL PASSAGE
SATURDAY NIGHT, ATTACHED TO GREAT LAKES LOW PRESSURE, ALLOWS FOR
SOUTHWEST FLOW PROMOTING STRONG HEATING DURING THE SUNDAY
DAYLIGHT HOURS. WELL-ABOVE NORMAL HIGH TEMPERATURES ARE
FORECAST, SUPPORTED BY 850MB TEMPERATURES APPROACHING 15C. HIGHS
WILL MAINLY BE IN THE 70S, PERHAPS NEAR 80 IN THE VICINITY OF
THE MASON-DIXON LINE. MUCAPE LEVELS OF AT LEAST 500-1000 J/KG
ARE SUGGESTED BY ENSEMBLES SUNDAY AFTERNOON, WITH A LOT OF THAT
IN THE IDEAL HAIL GROWTH ZONE. 0-6KM SHEAR MAY TOP OUT IN THE
RANGE OF 50-60 KNOTS. AS ANOTHER COLD FRONT DROPS ACROSS THE
REGION DURING THE AFTERNOON AND EVENING, SOME SUPERCELL
STRUCTURES MAY BE SUPPORTED IN THIS ENVIRONMENT, WITH ALL SEVERE
HAZARDS ON THE TABLE. AT PRESENT, PARAMETERS APPEAR BEST
ALIGNED IN EASTERN OHIO AND LEAKING OVER INTO SOUTHWESTERN
PENNSYLVANIA. ACCORDINGLY, SPC HAS EXPANDED THE SLIGHT RISK
(LEVEL 2 OF 5) INTO SOUTHWESTERN PENNSYLVANIA, WITH A MARGINAL
RISK (LEVEL 1 OF 5) ENCOMPASSING THE REST OF OUR AREA.
WEAKENING CONVECTION WOULD ACCOMPANY THE FRONT THROUGH THE
NIGHT, WITH DRY WEATHER AND COOLER TEMPERATURES RETURNING FOR
MONDAY.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
THE FIRST ROUND OF AFTERNOON/EVENING RAIN SHOWERS CONTINUE TO
PUSH OFF TO THE SOUTHEAST THROUGH THE REMAINDER OF THIS EVENING.
MEANWHILE, UPSTREAM NEAR THE LAKE ERIE SHORELINE, RADAR AND
SATELLITE IMAGERY SUGGEST SOME ISOLATED CONVECTION IS BEGINNING
TO DEVELOP BEHIND THE ADVANCING COLD FRONT, AS WAS FORECAST IN
SOME CONVECTIVE-ALLOWING MODELS. THIS ACTIVITY MAY CONTINUE TO
INCREASE TO A SCATTERED COVERAGE AS IT MOVES THROUGH THE AREA
FROM NORTHWEST TO SOUTHEAST DURING THE 01Z TO 05Z TIMEFRAME.
SOME THUNDERSTORMS WILL BE POSSIBLE WITH THIS SECOND ROUND AS
ELEVATED INSTABILITY INCREASES DUE TO STEEPENING MID-LEVEL
LAPSE RATES. CAN'T RULE OUT SOME HAIL AND STRONG WIND GUSTS IN
ANY OF THE STRONGER STORMS, THOUGH THAT POTENTIAL REMAINS LOW.
THE UPTICK IN LIGHTNING ACTIVITY IS REFLECTED IN THIS TAF CYCLE
VIA THE MENTION OF -TSRA IN PROB30S, EXCEPT AT ZZV WHICH IS TOO
FAR WEST AND FKL/DUJ WHICH ARE TOO FAR NORTHEAST.
FOLLOWING THE FRONTAL PASSAGE AND SECOND ROUND OF SCATTERED
SHOWERS/STORMS, CEILINGS DROP TO MVFR UNDER POST-FRONTAL NW
FLOW AND COLD ADVECTION. GRADUAL IMPROVEMENT IS ANTICIPATED
DURING LATE MORNING AND AFTERNOON HOURS ON SATURDAY, AT WHICH
POINT VFR PREVAILS THROUGH THE REMAINDER OF THE TAF PERIOD.
OUTLOOK...
A FRONTAL PASSAGE COULD RETURN STRONG THUNDERSTORMS AND
ASSOCIATED RESTRICTIONS TO THE REGION SUNDAY AFTERNOON AND
EVENING. RESTRICTIONS LINGER INTO MONDAY MORNING BEFORE VFR
RETURNS MONDAY AFTERNOON THROUGH EARLY NEXT WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...MLB/CL
AVIATION...CERMAK
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