009
FXUS61 KPBZ 291212
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
812 AM EDT WED APR 29 2026
WHAT HAS CHANGED
NO SIGNIFICANT FORECAST CHANGES. THERE IS A MARGINAL RISK FOR
SEVERE THUNDERSTORMS FOR SOUTHERN PORTIONS OF THE AREA ON
WEDNESDAY.
KEY MESSAGES
1) RAIN RETURNS THIS MORNING. THUNDERSTORM CHANCES THIS
AFTERNOON.
2) BELOW-AVERAGE TEMPERATURES AND FROST/FREEZE CONDITIONS
POSSIBLE FRIDAY AND THROUGH THE WEEKEND.
DISCUSSION
KEY MESSAGE 1...
RAIN WILL OVERSPREAD THE REGION AFTER SUNRISE THIS MORNING AS
SURFACE LOW PRESSURE TRACKS ACROSS THE REGION. MEAGER
INSTABILITY WILL KEEP THUNDERSTORM CHANCES GENERALLY LOW AND
ISOLATED, BUT A FEW STRONG TO SEVERE STORMS CANNOT BE
COMPLETELY RULED OUT SOUTH AND EAST OF PITTSBURGH FROM MID-
AFTERNOON TO EARLY EVENING WITH A 30-40KT LOW-LEVEL JET AND
FAVORABLE SHEAR. SUFFICIENT DESTABILIZATION FOR THIS WILL BE
DEPENDENT ON BRIEF CLEARING LATE THIS MORNING/EARLY AFTERNOON.
LATEST ENSEMBLE GUIDANCE SHOWS A 30-50% PROBABILITY OF >500
J/KG CAPE AND 10% PROBABILITY OF >1000 J/KG CAPE FOR AREAS SOUTH
OF PITTSBURGH.
DAMAGING WIND GUSTS ARE THE PRIMARY HAZARD, THOUGH AN OVERLY
AMBITIOUS STORM COULD SUPPORT A BRIEF TORNADO GIVEN THE SHEAR
PROFILE. SEVERE WEATHER IS LESS LIKELY ACROSS EASTERN OHIO AND
NORTH OF I-70 WHERE AFTERNOON THUNDER CHANCES ARE LOW. SPC HAS
MAINTAINED A MARGINAL RISK FOR SEVERE STORMS, SOUTH AND EAST OF
PITTSBURGH -- DEPENDENT ON SUFFICIENT DESTABILIZATION THIS
AFTERNOON.
ADDITIONAL RAINFALL TODAY IS EXPECTED TO RANGE FROM 0.5" TO 1.0"
ACROSS THE REGION, WITH HEAVIEST RAIN EXPECTED IN THUNDERSTORMS
THIS AFTERNOON. GIVEN RECENT GREEN-UP AND DRIER ANTECEDENT
CONDITIONS, FLOODING CONCERNS ARE MINIMAL.
KEY MESSAGE 2...
MOSTLY QUEST WEATHER IS EXPECTED FOR THE REMAINDER OF THIS WEEK
INTO EARLY NEXT. OTHER THAN SOME LIGHT SHOWER CHANCES, THE MAIN
STORY FOR THAT PERIOD WILL BE COOLER TEMPERATURES AND POTENTIAL
FOR FROST/FREEZE CONDITIONS IN PORTIONS OF THE AREA.
DEEP GREAT LAKES/NORTHEAST TROUGHING WILL PROMOTE COLD ADVECTION
UNDER NORTHWESTERLY FLOW ALOFT. LOW TEMPERATURES IN THE 30S ARE
EXPECTED FOR MOST OF THE AREA FRIDAY, SATURDAY, AND SUNDAY
MORNINGS. PROBABILITIES FOR TEMPERATURES LESS THAN 37F PEAK AT
90% FOR MOST LOCATIONS NORTH OF PITTSBURGH SATURDAY MORNING,
BUT REMAIN GENERALLY ABOVE 45% EVERY WHERE EXCEPT IMMEDIATE
RIVER VALLEYS. FROST/FREEZE HEADLINES WILL LIKELY BE NEEDED
FRIDAY THROUGH SUNDAY.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
A MIXED BAG OF RESTRICTIONS IN THUNDER, CIGS, AND VIS ARE
EXPECTED TODAY AS A SURFACE LOW PASSES OVERHEAD. SHOWERS ARE
ENCROACHING FROM THE SOUTHWEST, WHICH WILL OVERSPREAD THE AREA
INTO THE AFTERNOON, LOWERING CIGS WITH A >80% CHANCE OF AT
LEAST MVFR AREA-WIDE THROUGH ROUGHLY TOMORROW MORNING.
IN THE MID AFTERNOON (ROUGHLY 18Z TO 00Z), A LINE OF MORE ROBUST
SHOWERS IS EXPECTED TO DEVELOP ON A COLD FRONT AND PASS FROM
WEST TO EAST. IF THE AREA IS ABLE TO GARNER ENOUGH INSTABILITY,
SOME STORMS MAY BE POSSIBLE, MOST LIKELY FOR SOUTHEASTERN PORTS
(PROB30S NOTED FOR NOW). THIS WILL NEED TO BE TRACKED CLOSER TO
REAL TIME.
THESE SHOWERS MAY ALSO TEMPORARILY DROP CIGS/VIS TO IFR WHERE
THE LINE IS MORE INTENSE. BEHIND THE HEAVIER SHOWERS AND RAIN
WILL BE A WIND SHIFT, WITH WINDS TRANSITIONING MORE NORTHWEST
BEHIND THE LINE. SOME GUSTS UP TO 20MPH AND CIGS BORDERLINE
MVFR/IFR ARE POSSIBLE THEREAFTER AND INTO THE OVERNIGHT HOURS.
TONIGHT, THERE IS COME UNCERTAINTY AS TO IF LOW CLOUDS SCATTER
OR REMAIN BROKEN, BUT REGARDLESS IFR IN CIGS (OR FOG IN
CLEARING) ARE POSSIBLE, PARTICULARLY CLOSER TO DAYBREAK.
OUTLOOK...
ISOLATED SHOWER ACTIVITY IS EXPECTED THURS AFTERNOON. CIGS WILL
LIKELY CLIMB BACK TO VFR AFTER SUNRISE WITH MIXING OF DRY AIR
FROM THE NORTHWEST.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...RACKLEY
AVIATION...MILCAREK
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