877
FXUS61 KPBZ 100820
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
420 AM EDT WED JUN 10 2026
WHAT HAS CHANGED
SEVERE WEATHER OUTLOOK UPGRADED TO SLIGHT (2/5) FOR THURSDAY AND
FRIDAY. SEVERE WEATHER TIMING AND LOCATION IS STILL VERY
UNCERTAIN GIVEN THE CURRENT WEATHER PATTERN.
KEY MESSAGES
1) POTENTIAL FOR SEVERE WEATHER EXISTS TODAY 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...
AN ACTIVE PATTERN OF EMBEDDED SHORTWAVES COINCIDENT WITH A VERY
WARM AND MOIST ENVIRONMENT WILL KEEP DAILY SHOWER AND
THUNDERSTORM CHANCES IN THE FORECAST TODAY AND THURSDAY.
STRONGER SHORTWAVE PASSAGE ALONG WITH A SURFACE COLD FRONT WILL
BRING MORE WIDESPREAD RAIN CHANCE ON FRIDAY, HELPING TO END THIS
SETUP TO BRIEFLY OFFER QUIETER AND MORE SEASONABLE WEATHER.
GIVEN THE WEAKLY-FORCED SUMMERTIME PATTERN, LOCATION AND TIMING
OF DAILY THUNDERSTORM INITIATION TODAY AND THURSDAY IS
UNCERTAIN AND DEPENDENT ON THE IMPACTS OF PRIOR CONVECTION
(PREVIOUS 12-24 HOURS), BOTH UPSTREAM AND LOCALLY. MODEL
GUIDANCE SUGGESTS A FAVORABLE ENVIRONMENT FOR DAMAGING WIND
GUSTS, A SECONDARY HAIL RISK, AND LOW BUT NON-ZERO TORNADIC
POTENTIAL. MEAN SBCAPE VALUES ARE PROGGED NEAR 2000 J/KG, WITH
DEEP-LAYER SHEAR AROUND 20KTS, AND DCAPE VALUES NEAR 1000J/KG.
CAMS HAVE STRUGGLED TO DEPICT ACCURATE INITIATION AND STORM
PLACEMENT IN THE LAST DAYS, AND TODAY/THURSDAY ARE UNLIKELY TO
BE DIFFERENT. LATEST CAMS SUGGEST CLEARING AFTER SHOWERS THIS
MORNING, WITH SOME CHANCE FOR ISOLATED STORMS THIS AFTERNOON,
BUT VERY LOW COVERAGE. STORM COVERAGE MAY INCREASE LATE THIS
AFTERNOON AND EVENING. A MARGINAL RISK FOR SEVERE STORMS IS
OUTLOOKED, GIVEN POTENTIAL FOR DAMAGING WIND IF STRONG STORMS DO
DEVELOP.
THURSDAY REMAINS UNCERTAIN WITH A WIDE RANGE OF SOLUTIONS
INCLUDING UPSTREAM MCSS AND MORE DISCRETE CLUSTERS. A SLIGHT
RISK FOR SEVERE STORMS (MAINLY DAMAGING WIND) IS OUTLOOKED, BUT
THIS WILL BE DEPENDENT ON STORM DEVELOPMENT AND TIMING. 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 AND ISOLATED RAIN SO FAR THIS WEEK
HELP TO LIMIT FLASH FLOODING POTENTIAL EVEN AS AREA PWATS NEAR
DAILY MAX SOUNDING CLIMATOLOGY. 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 /07Z WEDNESDAY THROUGH SUNDAY/
MAINLY IFR CEILINGS ARE EXPECTED THROUGH THE MORNING AS A WARM
AND HUMID AIRMASS REMAINS IN PLACE. SLOW IMPROVEMENT THROUGH
MVFR AND BACK TO VFR IS EXPECTED BY LATE MORNING INTO THE
AFTERNOON WITH DAYTIME HEATING AND MIXING.
A CROSSING SHORTWAVE WILL RETURNS SHOWERS AND THE OCCASIONAL
RUMBLE OF THUNDER FROM THE WEST EARLY THIS MORNING, NEARING ZZV
BY AROUND 09Z AND PIT BY AROUND 11Z. KEPT VISIBILITY FOR THESE
AT 5-6 MILES IN MOST CASES, BUT CANNOT RULE OUT AN ISOLATED,
BRIEF MORE RESTRICTIVE SHOWER. SCATTERED SHOWERS AND STORMS MAY
FIRE IN THE HUMID AIR MASS DURING THE AFTERNOON AND INTO THE
EVENING, BUT CONFIDENCE IN TIMING AND LOCATION IS LOW. INCLUDED
PROB30 GROUPS AT ALL SITES TO ACCOUNT FOR THIS.
WARM AND MOIST CONDITIONS WILL AGAIN ALLOW CEILINGS TO LOWER
WEDNESDAY NIGHT.
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 NEAR DAWN HOURS. CONFIDENCE REMAINS LOW IN TIMING AND
LOCATION OF THUNDERSTORMS EACH DAY GIVEN THE PATTERN. CHANCES
FOR STRONG/SEVERE THUNDERSTORMS WILL INCREASE EACH DAY WITH
POST-FRONTAL REPRIEVE ON SATURDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...RACKLEY/FRAZIER
AVIATION...RACKLEY
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