686
FXUS61 KPBZ 261139
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
739 AM EDT FRI JUN 26 2026
WHAT HAS CHANGED
THE KEY MESSAGE FOR THURSDAY HAS BEEN REMOVED.
KEY MESSAGES
1) A STALLED BOUNDARY KEEPS RAIN CHANCES IN THE FORECAST FRIDAY
AND SATURDAY, WITH SOME POTENTIAL FOR HEAVY RAINFALL AT TIMES
THAT COULD LEAD TO MINOR FLOODING.
2) HIGH CONFIDENCE IN THE DEVELOPMENT OF HOT AND HUMID
CONDITIONS NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...
A COLD FRONT WILL SAG SOUTH TODAY AND SET UP ALONG THE I-70
CORRIDOR. ALONG THIS REGION AND SOUTH WILL BE A FOCAL POINT FOR
SHOWERS AND THUNDERSTORMS TO DEVELOP. WITH A SHORTWAVE TROUGH
PASSING OVERHEAD FOR FRIDAY AFTERNOON AND FOLLOWED BY ADDITIONAL
DISTURBANCES THROUGH THE WEEKEND, AN AREA OF MODERATE TO HEAVY
RAINFALL WILL DEVELOP. THE SURGE OF MOISTURE INTO THE AREA WILL
ALLOW PWATS BETWEEN 1.6 AND 1.8 MOVING INTO THE SOUTHERN
FORECAST AREA. HOWEVER, THE RECENT RUN OF THE ENSEMBLES SUGGEST
A MARKETED SHIFT TO THE SOUTH WITH THE HEAVIEST AXIS OF THE
HEAVY RAINFALL. THIS WILL NEED TO BE MONITORED AS THE NBM PROBS
TO SURPASS 1 INCH THROUGH THE HEAVIEST RAINFALL PERIOD THIS
WEEKEND IS ONLY 70% AND THE HIGHER PROBS ARE SOUTHWEST OF OUR
FORECAST AREA. THUS, HAVE ELECTED TO HOLD OFF ON THE FLOOD WATCH
AS CONFIDENCE IS LOW AT THIS TIME GIVEN THE SHIFT IN THE
ENSEMBLES.
KEY MESSAGE 2...
THE BOUNDARY IS SET TO LIFT BACK NORTH OF THE REGION MONDAY.
THERE IS BROAD MODEL AGREEMENT ON A STRONG 500MB UPPER HIGH ON
THE ORDER OF 597 DM FORMING OVER THE OHIO VALLEY IN THE VICINITY
OF SOUTHERN INDIANA. THE MAIN IMPACT OF THIS PATTERN IS LIKELY
TO BE THE SEASON'S FIRST SUSTAINED RUN OF HEAT AND HUMIDITY,
WITH THE NBM INDICATING 70 PERCENT OR GREATER CHANCE OF 90+ HIGH
TEMPERATURES OVER MOST OF THE NON- RIDGE AREAS TUESDAY THROUGH
THURSDAY. ACCORDINGLY, PROBABILISTIC HEAT RISK GUIDANCE SHOWS
70% OR GREATER CHANCE OF MAJOR (LEVEL 3 OF 4) OR HIGHER IMPACTS
OVER MOST OF THE CWA. WE HAVE DETERMINISTIC HEAT INDICES IN THE
LOWLANDS OF 100 TO 105 BOTH TUESDAY AND WEDNESDAY WHICH ARE
REPRESENTATIVE. LOOKING AT THE NBM WEDNESDAY JULY 1ST 21Z
APPARENT TEMPERATURE PERCENTILES, THE 10TH AND 90TH RANGE FROM
93F-104F AT KPIT, BUT FOR DOWNTOWN PITTSBURGH THE VALUES ARE
100-115F. THOSE LARGE SPREADS ARE TYPICAL AND DURING HEAT WAVES
THE DAILY CLOUD COVER AND THUNDERSTORMS CHANCES ALSO CAUSE
UNCERTAINTY BUT THE MAIN MESSAGE IS HOT AND HUMID NEXT WEEK.
SECONDARY TO THE HEAT WILL BE THE EVENTUAL REINTRODUCTION OF
SOME LEVEL OF SEVERE WEATHER RISK. MOST LIKELY, GIVEN THE
ABUNDANT BUOYANCY POTENTIAL AND WEAK FLOW, THIS WOULD COME IN
THE FORM OF TYPICAL MID-SUMMER WET DOWNBURST WIND THREATS.
THERE IS A LOWER-END POTENTIAL FOR A SUPPRESSED RIDGE BY THE END
OF THE WEEK, WHICH COULD CREATE A UPPER LEVEL NORTHWEST FLOW
SETUP, A PATTERN WHICH HAS BEEN RESPONSIBLE FOR NOTABLE SEVERE
WEATHER EVENTS IN THE PAST. OF COURSE, THERE IS PLENTY OF TIME
TO MONITOR FOR THAT POTENTIAL.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
A MIX OF MVFR TO AS LOW AS LIFR CONDITIONS ARE ONGOING TO START
THE 12Z TAF CYCLE THIS MORNING. THESE CONDITIONS PREVAIL THROUGH
ROUGHLY 14Z AFTER WHICH IMPROVEMENT IS ANTICIPATED ESPECIALLY
FOR NORTHERN TERMINALS WHICH HAVE THE HIGHEST PROBABILITIES OF
RETURNING TO VFR BY MID TO LATE MORNING. RESTRICTIONS RETURN
LATE TODAY INTO TONIGHT AS ANOTHER ROUND OF RAIN MOVES INTO THE
AREA FROM THE WEST, STARTING SOUTH OF I-70 AFTER 18Z AND
SPREADING ELSEWHERE ACROSS THE AREA AFTER 00Z. HIGHEST
PROBABILITIES FOR THUNDER WILL BE AT ZZV AND MGW DUE TO THEIR
CLOSER PROXIMITY TO A STALLED BOUNDARY TO OUR SOUTH. FARTHER
NORTH, MOSTLY JUST SHOWERS ARE EXPECTED. WINDS REMAIN LIGHT AND
VARIABLE THROUGHOUT THE FORECAST PERIOD.
OUTLOOK...
THE ACTIVE WEATHER PATTERN CONTINUES THROUGH THE WEEKEND WITH
MULTIPLE ROUNDS OF SHOWERS/THUNDERSTORMS AS WELL AS PERIODIC
RESTRICTIONS MAINLY ASSOCIATED WITH HEAVIER INSTANCES OF RAIN.
DRIER NORTHWEST FLOW AND HIGH PRESSURE BUILD INTO THE AREA
STARTING SUNDAY, LEADING TO DRIER WEATHER AND LOWER
PROBABILITIES FOR RESTRICTIONS EARLY NEXT WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...SHALLENBERGER
AVIATION...CERMAK
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