713
FXUS61 KPBZ 240600
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
200 AM EDT SUN MAY 24 2026
WHAT HAS CHANGED
FLOOD WATCH EXPIRED AT 2AM. MONITORING THE POTENTIAL FOR
LOCALLY HEAVY RAINFALL THIS AFTERNOON AND EVENING WITH A
CROSSING SHORTWAVE TROUGH. NO OTHER MAJOR CHANGES TO THE
FORECAST AT THIS TIME.
KEY MESSAGES
1) SHOWERS/THUNDERSTORMS EXPECTED TO INCREASE TODAY INTO
TONIGHT
2) SHOWER/THUNDERSTORM CHANCES CONTINUE AT TIMES INTO THE
MIDDLE OF NEXT WEEK MAINLY SOUTH OF I-80. DRY AND SEASONABLE BY
LATE WEEK
DISCUSSION
KEY MESSAGE 1...
SCATTERED SHOWERS WILL CONTINUE EARLY THIS MORNING AHEAD OF A
SURFACE BOUNDARY CURRENTLY ACROSS EASTERN OHIO. THE BOUNDARY
SHOULD DISSIPATE LATER THIS MORNING. LET THE CURRENT FLOOD
WATCH EXPIRE AT 2AM, WITH RAINFALL RATES LIGHT ENOUGH TO NOT
RESULT IN FLOODING THIS MORNING.
WATER VAPOR IMAGERY AND THE LATEST MODELS SHOW THE NEXT
SHORTWAVE TO OUR W AND SW. THIS WAVE WILL ADVANCE NORTHEASTWARD
TODAY, CROSSING THE UPPER OHIO VALLEY REGION LATER TODAY INTO
TONIGHT. SHOWERS WILL BECOME MORE NUMEROUS ACROSS THE REGION
WITH THE APPROACH OF THE SHORTWAVE. HREF ML CAPE SHOWS 500-750
J/KG THIS AFTERNOON, WITH AROUND 30KT OF 0-6KM SHEAR, SO A FEW
THUNDERSTORMS WILL BE POSSIBLE AS WELL. PWATS INCREASE TO
AROUND 1.6 IN THIS AFTERNOON AND EVENING. WHILE THERE REMAINS A
POTENTIAL FOR FLOODING, ESPECIALLY ACROSS EASTERN OHIO, CAMS
INDICATE HEAVIER CELLS COULD BE SCATTERED WITH SUFFICIENT
MOVEMENT TO PRECLUDE A WIDESPREAD FLOOD/FLASH FLOOD POTENTIAL.
WILL HIGHLIGHT THIS POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK,
AND MONITOR FOR THE NEED FOR ANY FLOOD OR FLASH FLOOD WATCHES.
INSTABILITY SHOULD DIMINISH AFTER SUNSET, THOUGH NUMEROUS
SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE AS THE SHORTWAVE
CROSSES THE REGION. PROBABILITIES RANGE FROM 50-60 PERCENT OF 1
INCH OF RAIN OVER 24 HRS FOR AREAS SOUTH OF I-80, WITH LESSES
AMOUNTS TO THE NORTH.
KEY MESSAGE 2...
THE SHORTWAVE TROUGH SHOULD BEGIN TO EXIT THE REGION MONDAY
MORNING, THOUGH THE LINGERING SURFACE TROUGH IS EXPECTED TO SET
UP ACROSS THE MID ATLANTIC TO THE LOWER OHIO VALLEY REGION
LATER IN THE DAY. MOST OF THE DAY SHOULD BE DRY NORTH OF I-70,
WITH SHOWER/THUNDERSTORM CHANCES CONTINUING TO THE SOUTH IN
CLOSER PROXIMITY TO THE TROUGH.
THE FLOW ALOFT IS EXPECTED TO BE FROM THE WEST, PARALLEL TO THE
BOUNDARY, THROUGH MID WEEK. THIS WILL KEEP THE BOUNDARY IN
PLACE, AND BRING PERIODIC SHOWER AND THUNDERSTORM CHANCES TO THE
REGION. THE CHANCE FOR RAIN PEAKS WEDNESDAY INTO WEDNESDAY
NIGHT AS A SHORTWAVE TROUGH ADVANCES SOUTHEASTWARD OUT OF CANADA
AND CROSSES THE UPPER OHIO VALLEY REGION. RESULTING NW FLOW
BEHIND THE SHORTWAVE SHOULD DRIVE THE SURFACE BOUNDARY OUT OF
THE AREA BY LATE THURSDAY. NW FLOW AND BUILDING HIGH PRESSURE
SHOULD RETURN DRY AND SEASONABLE WEATHER TO THE AREA BY LATE
WEEK.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
COVERAGE OF SHOWERS HAS BLOSSOMED A BIT TO THE SOUTH/WEST OF
PITTSBURGH, AND ALONG A BOUNDARY FROM NEAR ERIE TO ZZV. THE
PRE-FRONTAL SHOWERS WILL ADVANCE NORTHEAST TOWARD PIT/AGC/HLG
OVER THE NEXT FEW HOURS, BUT THIS PLUME WILL CONCURRENTLY BE
SHUNTED TO THE EAST, LIMITING ITS TENURE IN SW PA. ALONG THE
FRONTAL BOUNDARY, SHOWERS WILL TRAIN, OFFERING A NARROW, FOCUSED
REGION OF POTENTIALLY IMPACTFUL RAINFALL, BUT WITH LIMITED
IMPACT TO TERMINALS.
SHOWERS ARE LIKELY TO WEAKEN WITH NEWD PROGRESS AS THE AIRMASS
TO THE NORTHWEST OF PITTSBURGH IS STRONGLY STABLE, THUS LIMITING
INTENSITY OF THESE SHOWERS AS THEY BECOME INCREASINGLY ELEVATED.
THE SCATTERED SHOWERS WILL PROGRESS THRU THE REGION, LEAVING A
MOIST BOUNDARY-LAYER AIRMASS IN THEIR WAKE. AS SUCH, HIGH
CONFIDENCE (GREATER THAN 80%) REMAINS IN WIDESPREAD IFR CIGS
TONIGHT THROUGH THE DAY ON SUN AT ALL AIRPORTS. REDUCTIONS IN
VSBY MAY BE LIMITED BY PERSISTENT WIND, WHICH WILL MAINTAIN A
BETTER-MIXED BOUNDARY LAYER TONIGHT UNTIL NEAR SUNRISE.
SOUTHEAST WIND WILL CONTINUE TO BE AT OR ABOVE THE 12 KNOT
THRESHOLD THROUGH MOST OF THE PERIOD WITH THE HISTORICAL WINDIER
PLACES IN THIS REGIME (LBE, DUJ, AGC, PIT, AND MGW) GUSTING
INTO THE OVERNIGHT HOURS UPWARDS OF 25-30 KNOTS BEFORE SUBSIDING
TOWARD MORNING.
WIDESPREAD IFR CIGS ARE LIKELY INTO SUN AFTERNOON AS ADDITIONAL
RAIN SHOWERS DEVELOP WHEN STRONGER FORCING FOR ASCENT APPEARS
PROBABLE. THESE COULD ONCE AGAIN POSE A THREAT OF MODERATE TO
HEAVY RAIN CAPABLE OF FURTHER VSBY RESTRICTIONS.
OUTLOOK...
CIGS COULD REMAIN IFR UNTIL MID-MORNING ON MEMORIAL DAY. WIDESPREAD
RAIN SHOWERS LATE SUN AFTERNOON WILL TAPER OFF WEST TO EAST
LATE SUN NIGHT, LEAVING A NEAR-SATURATED BOUNDARY LAYER.
RESTRICTIONS IN VSBY (POTENTIALLY LIFR OR LESS) ARE POSSIBLE
BY EARLY MON MORNING, ESPECIALLY IN LOCALIZED AREAS WHERE
ABUNDANT RAINFALL OCCURS ON SUN AFTERNOON/EVENING.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...WM
AVIATION...KRAMAR/MCMULLEN
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