617
FXUS61 KPBZ 091726
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
126 PM EDT TUE JUN 9 2026
WHAT HAS CHANGED
EXPANDED DISCUSSION ON AN ACTIVE WEATHER PATTERN FEATURING
MULTIPLE PERIODS WITH NON-ZERO HAZARDOUS WEATHER CONCERNS
THROUGH EARLY SATURDAY MORNING.
KEY MESSAGES
1) POTENTIAL FOR SEVERE WEATHER EXISTS WEDNESDAY THROUGH FRIDAY
BUT LARGE UNCERTAINTY EXISTS IN TIMING/COVERAGE/THREATS
2) LOW PROBABILITY FLASH FLOODING CONCERNS EXISTS THROUGH FRIDAY
DUE TO WARM, MOIST ENVIRONMENT
3) ABOVE AVERAGE TEMPERATURE WITH POTENTIAL FOR RECORD HIGH
MINIMUMS POSSIBLE THROUGH FRIDAY, PENDING STORM OUTCOMES
DISCUSSION
KEY MESSAGE 1...
THOUGH THE UPPER LEVEL PATTERN MAY FEATURE SMALL, EMBEDDED
SHORTWAVES WITHIN THE RIDGE TOP AXIS, THE OVERALL PATTERN THIS
WEEK PUTS THE UPPER OHIO RIVER VALLEY IN A WARM, MOIST
ENVIRONMENT CONDUCIVE TO SHOWER AND THUNDERSTORM DEVELOPMENT
THROUGH FRIDAY. BETTER SHORTWAVE TROUGH MOVEMENT WITH SURFACE
FRONTAL PUSH FRIDAY INTO EARLY SATURDAY MORNING HELPS END THIS
SETUP TO (AT LEAST BRIEFLY) OFFER QUIETER AND MORE SEASONABLE
WEATHER.
FOR WEDNESDAY AND THURSDAY, MODEL GUIDANCE SUGGESTS STORM
ENVIRONMENTS COULD BE FAVORABLE FOR DAMAGING WIND (MOST LIKELY)
AND LARGE HAIL (WITH A LIMITED NOD TO TORNADIC POTENTIAL) AS
MEAN SBCAPE VALUES ARE AROUND 2000 J/KG, 0-6KM SHEAR AROUND
20KTS, AND DCAPE AROUND 1000 J/KG. HOWEVER, HIGH UNCERTAINTY
EXISTS DUE TO A COMBINATION OF WEAK FORCING/LIFTING CREATING
LARGE SPREADS IN INITIATION LOCATIONS AND IMPACTS OF CONVECTION
(BOTH UPSTREAM AND LOCALLY) DURING THE PRIOR 12-24 HOURS
ALTERING THE ANTICIPATED ENVIRONMENT. A QUICK PERUSAL ACROSS
VARIOUS CONVECTIVE-ALLOWING DETERMINISTIC MODEL REFLECTIVITY
OUTPUT HIGHLIGHT THE VAST SCOPE OF STORM OUTCOMES, WITH SOME
SHOWING LITTLE TO NO CONVECTION (DUE TO SUBSIDENCE BETWEEN WAYS)
FOR WEDNESDAY WHILE OTHERS DEVELOP STRONG EVENING CLUSTERS IN
EASTERN OH OR A POTENTIAL MCS DURING THE OVERNIGHT HOURS INTO
THURSDAY. THIS SHOWS THAT EVEN STORM MODE REMAINS UNCERTAINTY,
TOGGLING BETWEEN MCS-LIKE STORM CLUSTERS VERSUS DISCRETE CELLS
CREATING MICROBURSTS AND/OR LARGE HAIL. BEST PRACTICE AT THIS
TIME WILL BE A CONTINUE MONITORING OF WEATHER INFORMATION TO
LEARN OF THE LATEST TRENDS AND NOT BE TOO SET ON PRIOR FORECASTS
WITH SUCH A FLUID SITUATION.
FOR FRIDAY, A MORE-DEFINED SHORTWAVE AND SURFACE BOUNDARY
CREATES GREATER CERTAINTY IN THE DEVELOPMENT OF CONVECTION AS
IT CROSSES THE REGION BUT TIMING DIFFERENCES IN ITS PASSAGE
AMONGST MODELS LENDS TO HIGHER VARIABILITY IN THE SEVERE
ENVIRONMENT. THE MOST LIKELY OUTCOME AT THIS TIME IS A QLCS-LIKE
FEATURE AHEAD OF THE FRONTAL BOUNDARY CROSSING DURING THE DAY
FRIDAY, WITH LATER ARRIVAL ALLOWING FOR STRONGER
HEATING/DESTABILIZATION TO CREATE LARGER HAZARDS THREAT
(FAVORING DAMAGING WIND) WHILE EARLIER ARRIVAL LIMITS AREA OF
CONCERN TO EASTERN LOCALES.
KEY MESSAGE 2...
DRY ANTECEDENT CONDITIONS HEADING INTO THIS WEEK HELP TO CREATE
A LIMIT OF FLASH FLOOD CONCERN EVEN AS AREA PWATS RISE AND HOLD
NEAR THE DAILY MAX SOUNDING CLIMATOLOGY THROUGHOUT THIS WEEK.
ADDITIONALLY, THE LACK OF STRONG DESTABILIZATION TODAY, DESPITE
LOW CORFIDI VECTORS SUGGESTING POTENTIAL FOR SLOW MOVEMENT
AND/OR BACK BUILDING, SHOULD LIMIT THE INTENSITY OF RAINFALL
RATES ENOUGH SUCH THAT FLASH FLOODING IS UNLIKELY AND ANY
OCCURRENCE IS VERY ISOLATED AND WITHIN/NEAR POOR DRAINAGE AREAS.
FLASH FLOOD RISKS ARE UNLIKELY TO EVOLVE MUCH THROUGH FRIDAY
(MEANING REMAINING LOW BUT NON-ZERO) AS GREATER INSTABILITY
DEVELOPMENT (RESULTING IN GREATER LIKELIHOOD FOR HIGH RAINFALL
RATES) THAT PROMOTES HIGHER FLOOD RISKS ARE OFFSET BY EITHER
GREATER FORWARD MOTION/PROPAGATION (FRIDAY) AND/OR LOW STORM
COVERAGE POTENTIAL (WEDNESDAY/THURSDAY). BUT GIVEN PWAT
REMAINING HIGH WITHIN THE WARM, UNSTABLE ENVIRONMENT, IT REMAINS
PRUDENT TO BE AWARE OF THE NON-ZERO FLOODING RISK IF ANY STORM
GENERATES RAINFALL RATES EXCEED 2"/HR AND SITS (OR TRAINS OVER)
THE SAME LOCATION FOR A LONG-ENOUGH DURATION.
KEY MESSAGE 3...
CONFIDENCE IS HIGH IN TEMPERATURES OF 5 TO 15
DEGREES ABOVE THE CLIMATOLOGICAL AVERAGE TODAY INTO THIS
WEEKEND. DAILY HIGH TEMPERATURES ARE LIKELY TO FALL SHORT OF THE
DAILY RECORD HIGHS IN THE MID/UPPER 90S THIS WEEK, ESPECIALLY
WITH DAILY SHOWER AND THUNDERSTORM CHANCES. HOWEVER, OVERNIGHT
LOWS IN THE LOWER 70S LATE WEEK WILL BE NEAR RECORD WARM
MINIMUMS. WARM OVERNIGHT TEMPERATURES ARE PARTICULARLY DANGEROUS
DURING PROLONGED PERIODS OF HEAT. LARGE PORTIONS OF THE AREA
HAVE A 70%+ CHANCE OF MAJOR HEAT RISK ON THURSDAY, WITH HIGH
PROBABILITIES OF MODERATE HEAT RISK OTHER DAYS THIS WEEK.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
GENERAL VFR IS EXPECTED THROUGH THE DAY OUTSIDE OF LOCAL
SHOWER/THUNDERSTORM-RELATED RESTRICTIONS.
SHOWERS WILL BE NEAR ZZV BVI FKL THIS MORNING AS INCREASE IN
WARM AND MOIST AIRMASS IN SOUTHWEST FLOW AHEAD OF TROUGH
CURRENTLY OVER INDIANA THAT IS DRIFTING UP THE OHIO VALLEY
TODAY. CONDITIONS WILL BE VFR FOR THE VAST MAJORITY OF AREA AND
ANY RESTRICTIONS SHOULD BE BRIEF WITH SHOWERS.
DAYTIME HEATING WITH INCREASING MOISTURE SHOULD RESULT IN MORE
WIDESPREAD SHOWER/THUNDERSTORM DEVELOPMENT AFTER 18Z. HEAVY RAIN
MAY RESULT IN PERIODS OF IFR OR LOWER VISIBILITIES. THUNDER
CHANCES WILL DIMINISH BY AROUND 03Z WEDNESDAY, BUT SCATTERED
SHOWERS SHOULD PERSIST THROUGH THE OVERNIGHT. CEILINGS WILL
LOWER INTO IFR OVERNIGHT THROUGH WEDNESDAY MORNING AS STRATUS
FORMS IN HUMID AIRMASS ENHANCED BY WIDESPREAD SHOWERS.
BECAUSE OF THE TROPICAL NATURE OF AIRMASS AND DEEP MOISTURE
PROFILES AND WEAK LAPSE RATES, HAIL AND UNUSUALLY STRONG WIND
GUSTS ARE NOT EXPECTED WITH THESE SHOWERS AND THUNDERSTORMS
THROUGH TONIGHT.
OUTLOOK...
A WARM, MOIST ENVIRONMENT WITH INTERMITTENT PASSING OF UPPER
SHORTWAVES FAVOR DAILY THUNDERSTORM CHANCES THROUGH THE REST OF
THE WEEK. RESTRICTIONS ARE LIKELY WITH ANY STORM WHILE EXCESSIVE
RAIN COULD CREATE CIG/VIS IMPACTS EVEN DURING NON-RAIN PERIODS,
LIKELY AROUND THE DAWN HOURS.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...FRAZIER/RACKLEY
AVIATION...CRAVEN
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