699
FXUS61 KPBZ 300516
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
116 AM EDT THU JUL 30 2026
WHAT HAS CHANGED
NO NOTABLE CHANGES HAVE OCCURRED WITHIN THE KEY MESSAGE AHEAD OF
THIS WEEKEND.
KEY MESSAGES
1) DRY AND SEASONABLE WEATHER FAVORED THIS WEEK BEFORE WIDESPREAD
RAIN RETURNS THIS WEEKEND.
DISCUSSION
KEY MESSAGE 1...
RISING PRESSURE HEIGHTS OVER SURFACE HIGH PRESSURE WILL ALLOW
AREA TEMPERATURE TO RETURN CLOSER TO NORMAL TODAY AND EVER SO
SLIGHTLY ABOVE NORMAL FRIDAY WHILE PROVIDING DRY WEATHER AND
ABUNDANT SUNSHINE.
THIS PATTERN CHANGES AS AN UPPER TROUGH DROPS SOUTHEAST OUT OF
THE NORTHERN ROCKIES TOWARDS THE OHIO RIVER VALLEY BY FRIDAY
EVENING BEFORE CROSSING THE REGION BY EARLY NEXT WEEK. THE
COMBINATION OF JET DYNAMICS PROVIDING LIFT WITH WEAK MOISTURE
ADVECTION AHEAD OF ITS AXIS RESULTS IN INCREASED SHOWER AND
THUNDERSTORM CHANCES. LITTLE MORE CAN BE SAID AT THIS POINT DUE
TO LARGE VARIANCES IN THE SHAPE AND EASTWARD PROGRESSION OF THIS
TROUGH CREATING DIFFERENT PRECIPITATION TIMING (ALONG WITH
ENVIRONMENTAL THREATS).
THE RANGE OF OUTCOMES SEEMS TO BE BOUNDED BY 1) A MORE
PROGRESSIVE TROUGH HINTED BY THE INITIAL 00Z NAM MODEL RUN THAT
RESULTS IN STORM COVERAGE PEAKING BY SATURDAY
AFTERNOON/EVENING; AND 2) A SLOWER AND SLIGHTLY DEEPER TROUGH
FAVORED BY A HEALTHY PORTION OF GEFS ENSEMBLE MEMBERS THAT
RESULTS IN STORMS PEAKING SUNDAY MORNING/AFTERNOON. ENSEMBLE
CLUSTERS GENERALLY FALL IN BETWEEN THESE TWO RANGES (PEAKING
LATE SATURDAY INTO EARLY SUNDAY) AND WHERE THE CURRENT FORECAST
ALIGNS. DUE TO THIS VARIANCE, PRECIPITATION CHANCES COULD VARY
IN THE COMING DAYS AS MODELS ATTEMPT TO COME IN ALIGNMENT.
ADDITIONAL UNCERTAINTY ARISES IN THE TIMING OF TROUGH EXITING,
RANGING FROM SUNDAY AFTERNOON/EVENING TO TUESDAY. SO LONG-RANGE
POP OUTLOOKS MAY ALSO EXPERIENCE SIMILAR FLUCTUATIONS IN THE
COMING DAYS.
REGARDLESS OF THE SCENARIOS, THE OVERALL HAZARD RISK APPEARS LOW
AS BUOYANCY IS LIKELY TO BE LIMITED (OUTSIDE OF A NARROW
CORRIDOR NEAR THE LAUREL HIGHLANDS ON SUNDAY, PROBABILITY OF
SBCAPE BEING LESS THAN 1000 J/KG IS GREATER THAN 80%). THE ONLY
HAZARD TO MONITOR IS FLOOD RISKS AS THERE COULD BE ENOUGH OF A
GULF MOISTURE DRAW TO PUSH PWAT VALUES NEAR/ABOVE THE 90TH
PERCENTILE; IF THIS OCCURS WHILE STORM MOTION IS SLOW AND ENOUGH
INSTABILITY MANIFESTS TO AID RAINFALL RATES, LOCALIZED FLASH
FLOODING RISKS COULD MATERIALIZE.
AVIATION /06Z THURSDAY THROUGH MONDAY/
HIGH CONFIDENCE VFR FORECAST THROUGH THE TAF PERIOD WITH DIURNAL
MIXING RESULTING IN A FEW CU AND OCCASIONAL NW WIND GUSTS TO
20KTS.
OUTLOOK...
VFR IS LIKELY THROUGH SATURDAY MORNING UNDER THE INFLUENCE OF
HIGH PRESSURE. SLOW UPPER TROUGH PASSAGE WILL RESULT IN MULTIPLE
PERIODS FEATURING SHOWER AND THUNDERSTORM CHANCES THIS WEEKEND
INTO EARLY NEXT WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...FRAZIER
AVIATION...FRAZIER
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