043
FXUS61 KPBZ 230526
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
126 AM EDT SUN AUG 23 2026
WHAT HAS CHANGED
RISK FOR SEVERE WEATHER THIS AFTERNOON/EVENING IN NORTHWEST PA
IS LOWER, WITH NO OTHER HAZARDOUS WEATHER ANTICIPATED THROUGH AT
LEAST MID WEEK.
KEY MESSAGES
1) SPOTTY SHOWERS WITH LOW PROBABILITY THUNDERSTORM CHANCES
POSSIBLE THROUGH THIS EVENING.
2) MINIMAL HAZARDS FOR MAJORITY OF WEEK BEFORE WIDESPREAD
PRECIPITATION CHANCES RETURN TO END THE WEEK.
DISCUSSION
KEY MESSAGE 1...
UPPER TROUGHING LINGERING OVER THE UPPER OH RIVER VALLEY
COMBINED WITH COLD ADVECTION OVER WARM LAKE ERIE WATERS IS
ENOUGH TO PRODUCED LOCALIZED, BRIEF SHOWERS WITH A LOW
PROBABILITY FOR THUNDERSTORMS THROUGH THIS EVENING. WHILE SBCAPE
PEAKS AROUND 1000 J/KG AROUND THE I-80 CORRIDOR (ENOUGH TO
FOSTER DEEPER CONVECTION), SUCH LACKLUSTER SHEAR (STRUGGLING TO
TOUCH 20KTS) SHOULD LIMIT ENOUGH ORGANIZATION/INTENSIFICATION
TO KEEP STORMS BELOW SEVERE THRESHOLDS.
ACTIVITY GENERALLY COMES TO AN END AFTER SUNSET AS SUBSIDENCE
AND LOSS OF HEATING SUPPRESSES ACTIVITY. THE EXCEPTION IS
NEAR/NORTH OF I-80 IN NORTHWEST PA WHERE AN EMBEDDED SHORTWAVES
IN NW COULD CREATE SHORT PERIODS WHERE SHOWERS (MAINLY) THROUGH
MONDAY.
KEY MESSAGE 2...
LINGERING COOL ADVECTION WITHIN NORTHWEST FLOW RESULTS IN
HIGH TEMPERATURES AROUND 10 DEGREES BELOW THE DAILY AVERAGE
MONDAY WHILE HIGH PRESSURE SUPPORTS DRY WEATHER (SAVE FOR A LOW
PROBABILITY SHOWER NEAR LAKE ERIE).
HEIGHT RISES OVER THE SURFACE HIGH ENSURES DRY WEATHER PERSISTS
TUESDAY INTO WEDNESDAY WHILE ELEVATING TEMPERATURE BACK TO NEAR
THE SEASONAL AVERAGES. ENSEMBLES REMAIN FIRM IN AN UPPER
SHORTWAVE DIGGING THROUGH THE OHIO RIVER VALLEY THURSDAY INTO
FRIDAY, CREATING THE NEXT ROUND OF WIDESPREAD SHOWER AND
THUNDERSTORM CHANCES. MODEL DIFFERENCES IN TIMING OF UPPER
SHORTWAVE AND SURFACE BOUNDARY MOVEMENT LEAVES LARGE VARIABILITY
IN POTENTIAL STORM ENVIRONMENTS (EX: SPREAD BETWEEN 25TH-75TH
PERCENTILE SBCAPE VALUES THURSDAY AFTERNOON IS AROUND 700 J/KG,
A SIGNIFICANT VALUE). TROUGH PASSAGE WITHIN THE SUMMER SEASON
MEANS THIS PERIOD SHOULD BE MONITORED, BUT LITTLE MORE CAN BE
CONFIDENTLY SAID AT THIS TIME.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
POCKETS OF MVFR TO LOCALLY IFR STRATUS REMAIN POSSIBLE AHEAD OF
THE SURFACE COLD EARLY THIS MORNING DUE TO RESIDUAL BOUNDARY
LAYER MOISTURE. A BRIEF LIGHT RAIN SHOWER CAN'T BE RULED OUT BUT
OVERALL ACTIVITY IS TOO LOCALIZED TO INCLUDE IN THE TAF.
DIURNAL HEATING/MIXING WITHIN THE POST-FRONTAL ENVIRONMENT
LIKELY FOSTERS SCATTERED TO BROKEN VFR CU (THOUGH A PERIOD OF
MVFR AS CIGS RISE IS POSSIBLE) TODAY. COOL NW FLOW MAY TAP INTO
WARM LAKE ERIE WATERS AS AN AID FOR GENERATING POP-UP BRIEF
AFTERNOON SHOWERS, WITH PROBABILITIES HIGHEST AT FKL/DUJ GIVEN
LAKE PROXIMITY. LINGERING SURFACE GRADIENT/STEEP LAPSE RATES
ALSO FOSTERS NW AFTERNOON WINDS BETWEEN 15-25KTS.
OUTLOOK...
OUTSIDE OF LOW PROBABILITY RAIN SHOWERS NEAR LAKE ERIE THROUGH
MONDAY, BUILDING HIGH PRESSURE AND HEIGHT RISES ALOFT FAVOR VFR
THROUGH THE MIDDLE OF NEXT WEEK.
THE NEXT WIDESPREAD RESTRICTION AND RAIN CHANCES RETURNS NEAR
THE END OF THE WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...FRAZIER
AVIATION...FRAZIER
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