035
FXUS61 KPBZ 290504
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
104 AM EDT WED JUL 29 2026
WHAT HAS CHANGED
MESSAGING FOCUSED ON THE WEEKEND WHEN WIDESPREAD PRECIPITATION
CHANCES RETURN, BUT WITH LIMITED RISKS.
KEY MESSAGES
1) DRY AND SEASONABLE WEATHER FAVORED THIS WEEK BEFORE
WIDESPREAD RAIN RETURNS THIS WEEKEND.
DISCUSSION
KEY MESSAGE 1...
THE UPPER OHIO RIVER VALLEY REMAINS ON THE WESTERN PERIPHERY OF
A FAIRLY STAGNANT CLOSED LOW OVER THE NEW ENGLAND REGION; SUCH
PATTERN DOES OFFER LOW PROBABILITY AFTERNOON SHOWER AND
THUNDERSTORM CHANCES TODAY MAINLY OVER THE HIGHER TERRAIN SE OF
PITTSBURGH (WHERE CONVERGENCE BEST ALIGNS). IT OTHERWISE FOSTERS
DRY WEATHER WITH SEASONABLE TEMPERATURE THAT SEES SUBTLE
TEMPERATURE RISES TO END THE WEEK AS PRESSURE HEIGHTS ALOFT
SLOWLY INCREASE.
THE WEEKEND OUTLOOK FEATURES THE NEXT TROUGH SYSTEM SLOWLY
CROSSING THE REGION WHILE GENERALLY SITTING WELL SOUTH OF THE
MAIN JET STREAM FARTHER NORTH. MODEST MOISTURE RETURNS
COMBINED WITH TROUGH-INDUCED LIFT LIKELY RESULTS IN AN UPTICK IN
WIDESPREAD SHOWERS AND THUNDERSTORMS FAVORING THE AFTERNOON TO
EARLY EVENING HOURS. PENDING THE TROUGH DEPTH AND EASTWARD
TRACK, THERE ARE LOW PROBABILITY SCENARIOS TO AMPLIFY MOISTURE
RETURNS IN SW FLOW SUCH THAT IT CREATES A LOW-END FLASH FLOOD
RISK (PWATS RISE TOWARD OR ABOVE THE 90TH PERCENTILE; WEAK-FLOW
AIDS SLOW-MOVING STORMS; ENOUGH CAPE TO ALLOW FOR WARM-RAIN
PROCESSES). THIS BEARS MONITORING IN WHAT OTHERWISE APPEARS TO
BE A LOW IMPACT PATTERN GIVEN MEAGER CAPE AND SHEAR VALUES.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
ENOUGH COOL ADVECTION OVER LAKE ERIE PLUS MOISTURE CONVERGENCE
ALONG THE HIGHER TERRAIN AS THE SURFACE LOW SITS NE OF THE
REGION WILL CREATE OPPORTUNITIES FOR GENERALLY MVFR STRATOCU
THROUGH 14Z. MORE LIMITED MOISTURE WITHIN THE BOUNDARY LAYER
LIKELY RESULTS IN CEILINGS TO BOUNCE BETWEEN SCATTERED AND
BROKEN WHILE OFFERING SOME VARIABILITY IN ON SET TIMING THAT MAY
NOT BE FULLY CAPTURED IN LATEST TAF.
DIURNAL HEATING AND MIXING SHOULD LIFT ANY STRATOCU TO VFR
HEIGHTS BY AROUND 18Z WEDNESDAY (THOUGH A BRIEF PERIOD OF BROKEN
MVFR COULD OCCUR AMID RISING) WHILE DRY ADVECTION SLOWLY ERODES
CU COVERAGE. THERE MAY BE ENOUGH LIFT WITHIN THE NW/N UPPER FLOW
TO PRODUCE AN ISOLATED AFTERNOON SHOWER (FAVORING EAST OF I-79)
BUT PROBABILITY OF TERMINAL IMPACT IS TOO LOW FOR A MENTION.
OUTLOOK...
VFR IS FAVORED THURSDAY INTO FRIDAY UNDER THE INFLUENCE OF HIGH
PRESSURE AND HEIGHT RISES ALOFT. THE NEXT PERIOD OF ACTIVE
STARTS SATURDAY AND CONTINUES INTO EARLY NEXT WEEK WITH THE SLOW
PASSING OF AN UPPER LEVEL TROUGH.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...FRAZIER
AVIATION...FRAZIER
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