801
FXUS61 KPBZ 250600
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
200 AM EDT SAT JUL 25 2026
WHAT HAS CHANGED
PORTIONS OF THE AREA HAVE BEEN ADDED TO A MARGINAL RISK FOR
SEVERE STORMS ON SUNDAY. A HIGHER SEVERE WEATHER POTENTIAL IS
EXPECTED MONDAY INTO TUESDAY.
KEY MESSAGES
1) ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORM POSSIBLE
TODAY AND SUNDAY
2) SEVERE THUNDERSTORM POTENTIAL INCREASES MONDAY INTO TUESDAY
DISCUSSION
KEY MESSAGE 1...
A RELATIVELY WEAK SHORTWAVE IS EXPECTED TO CROSS THE UPPER OHIO
VALLEY REGION TODAY. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED,
THOUGH MUCH OF THE DAY SHOULD BE DRY. BY THIS AFTERNOON, MOST OF
THE SHOWER ACTIVITY SHOULD BE EAST OF I-79, ALONG A MID LEVEL
TROUGH. INSTABILITY IS PROGGED TO BE MINIMAL, WITH ONLY AN
ISOLATED THUNDERSTORM POSSIBLE. THIS ACTIVITY SHOULD DIMINISH
THIS EVENING AS THE SHORTWAVE EXITS TO THE EAST.
SUNDAY SHOULD START WITH DRY WEATHER AHEAD OF ANOTHER
APPROACHING SHORTWAVE. THIS WAVE SHOULD BRING SCATTERED SHOWERS
AND THUNDERSTORMS TO PORTIONS OF THE AREA, INITIALLY NORTH AND
WEST OF PITTSBURGH, BY AFTERNOON INTO THE EVENING. ADDITIONAL
CONVERGENCE ALONG A LAKE BREEZE BOUNDARY COULD ALSO ENHANCE SOME
OF THE THUNDERSTORM COVERAGE. LOW AND MID LEVEL FLOW IS
EXPECTED TO REMAIN RELATIVELY WEAK, THOUGH AN UPPER JET IS
EXPECTED TO APPROACH OHIO IN THE AFTERNOON. GENERALLY A LOW
POTENTIAL EXISTS FOR SEVERE STORMS ON SUNDAY, THOUGH DCAPE
VALUES AROUND 750 J/KG INDICATE SOME DAMAGING WIND GUSTS WILL BE
POSSIBLE. THE STORM PREDICTION CENTER HAS INCLUDED MUCH OF OHIO
IN A MARGINAL RISK FOR SEVERE STORMS.
KEY MESSAGE 2...
THUNDERSTORM CHANCES ARE EXPECTED TO INCREASE BY MONDAY IN
NORTHWEST FLOW ALOFT. AN MCS IS POSSIBLE ACROSS THE MIDWEST TO
THE OHIO VALLEY REGION SUNDAY NIGHT INTO MONDAY MORNING.
CURRENT INDICATIONS ARE THIS SHOULD STAY WEST OF THE FORECAST
AREA FOLLOWING THE 500 MB THICKNESS PATTERN, THOUGH THIS WILL
NEED TO BE MONITORED AS DETAILS BECOME MORE CERTAIN.
BY AFTERNOON, BUILDING DIURNAL INSTABILITY AND A SUBTLE
CROSSING SHORTWAVE SHOULD RESULT IN INCREASING SHOWERS AND
THUNDERSTORMS, AND A SEVERE WEATHER POTENTIAL. ML CAPE IS
PROGGED FROM 1500-2500 J/KG, WITH INCREASING FLOW ALOFT
RESULTING IN 40 KT OF 0-6KM SHEAR. THE POTENTIAL FOR SEVERE
STORMS IS EXPECTED TO CONTINUE INTO MONDAY NIGHT AS A STRONGER
SHORTWAVE AND SURFACE COLD FRONT APPROACH FROM THE GREAT LAKES
REGION. AGAIN, THERE WILL BE A POTENTIAL FOR AN MCS SOMEWHERE IN
THE REGION, THOUGH LOW CONFIDENCE CONTINUES IN THE LOCATION AND
TIMING OF THIS POTENTIAL.
THE SHORTWAVE AND SURFACE COLD FRONT IS PROGGED TO CROSS THE
UPPER OHIO VALLEY REGION ON TUESDAY. A SEVERE WEATHER POTENTIAL
IS EXPECTED TO CONTINUE, THOUGH THIS WILL BE HIGHLY DEPENDENT ON
THE TIMING OF PASSAGE, AND ANY MCS ACTIVITY MONDAY NIGHT/TUESDAY
MORNING.
THE LATEST MACHINE LEARNING GUIDANCE INDICATE THE HIGHEST
POTENTIAL FOR SEVERE STORMS SHOULD BE FROM 12Z MONDAY THROUGH
12Z TUESDAY. THE HIGHEST POTENTIAL ON TUESDAY IS INDICATED
ACROSS FAR SE OH, SW PA, AND NORTHERN WV. ALL HAZARDS ARE
POSSIBLE, WITH DAMAGING WIND, HAIL, ISOLATED TORNADOES AND
LOCALLY HEAVY RAINFALL/FLASH FLOODING. LOW CONFIDENCE REMAINS IN
THE TIMING/LOCATION, AND HOW THESE POTENTIAL HAZARDS WILL BE
IMPACTED BY PREVIOUS CONVECTION, OUTFLOWS, ETC.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
A WEAK SHORTWAVE TROUGH SHOULD RESULT IN INCREASING
STRATOCUMULUS CLOUDS EARLY THIS MORNING. THERE IS SOME POTENTIAL
FOR MVFR CIGS, THOUGH LOW VFR APPEAR MORE LIKELY ACCORDING TO
MODEL SOUNDINGS AND ENSEMBLE PROBABILITIES. ISOLATED SHOWERS ARE
ALSO POSSIBLE THIS MORNING, THOUGH THESE WERE NOT INCLUDED IN
THE TAFS AT THIS TIME DUE TO THE LIMITED COVERAGE.
THE SHORTWAVE IS EXPECTED TO CROSS THE AREA THIS AFTERNOON, WITH
CONTINUED STRATOCU CIGS AND ISOLATED TO SCATTERED SHOWERS.
INSTABILITY IS EXPECTED TO BE LIMITED, THOUGH AN ISOLATED
THUNDERSTORM WILL BE POSSIBLE. MOST OF THE AFTERNOON ACTIVITY IS
EXPECTED TO BE ALONG AN EAST OF THE I-79 CORRIDOR. INCLUDED SOME
PROB30S FOR SHOWERS FOR SITES EAST OF I-79, WITH VCSH FOR THE
MORE ISOLATED ACTIVITY ELSEWHERE. THESE SHOWERS SHOULD END THIS
EVENING AS THE SHORTWAVE EXITS, WITH CLOUDS ALSO DECREASING.
OUTLOOK...
ISOLATED TO SCATTERED SHOWERS/STORMS ARE POSSIBLE SUNDAY
AFTERNOON WITH A SHORTWAVE TROUGH. INCREASING SHOWER/STORM
CHANCES ARE EXPECTED MONDAY INTO TUESDAY WITH THE APPROACH AND
PASSAGE OF A COLD FRONT. A FEW SEVERE STORMS WILL BE POSSIBLE.
LOW SHOWER/STORM CHANCES CONTINUE WEDNESDAY WITH ANOTHER WAVE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...WM
AVIATION...WM
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