224
FXUS61 KPBZ 110741
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
341 AM EDT FRI SEP 11 2026
WHAT HAS CHANGED
UPDATE TO KEY MESSAGES AND AVIATION DISCUSSION.
KEY MESSAGES
1) WIDESPREAD RAIN AND ISOLATED THUNDERSTORMS EXPECTED EARLY
SATURDAY WITH NEW DISTURBANCE
2) MONITORING THE POTENTIAL FOR STRONG TO SEVERE STORMS SUNDAY
EVENING WITH A COLD FRONT
DISCUSSION
KEY MESSAGE 1...
A WEAK SHORTWAVE WILL EXIT THE REGION EARLY THIS MORNING,
ALLOWING DRIER AND QUIETER CONDITIONS TO DEVELOP AFTER 9AM. NO
HAZARDOUS WEATHER IS FORECASTED FOR TODAY.
A NEW DISTURBANCE, ADVANCING FROM THE SOUTH, WILL INCREASE THE
POTENTIAL FOR RAIN SHOWERS AND THUNDERSTORMS SATURDAY MORNING
AND WILL LIKELY CONTINUE INTO THE EVENING HOURS. THE PRIMARY
THREAT WITH THIS SYSTEM HEAVY RAINFALL, WHICH COULD LEAD TO
LOCALIZED FLOODING CONCERNS. HIGH-RESOLUTION MODELS CURRENTLY
SUGGEST THE GREATEST FLOOD POTENTIAL WILL BE SOUTH AND/OR
SOUTHEAST OF PITTSBURGH. HIGH-RESOLUTION MODELS INDICATE A
30-50% PROBABILITY THAT FORECASTED RAINFALL AMOUNTS WILL EXCEED
6 HOUR FLASH FLOOD GUIDANCE DURING SATURDAY EVENING. SWATHS OF 1
TO 2 INCHES OF RAINFALL COULD OCCUR.
DEEP AMPLE MOISTURE AND WEAK SHEAR, GENERALLY BELOW 30KTS, WILL
REDUCE THE RISK FOR STRONG TO SEVERE THUNDERSTORMS SATURDAY. THE
LACK OF SUFFICIENT DRY AIR WILL REDUCE THE RISK OF DAMAGING
DOWNDRAFTS. LIGHTNING WILL LIKELY REMAIN THE SECONDARY HAZARD
DURING THE AFTERNOON AND EVENING HOURS.
THE RISK FOR MODERATE TO HEAVY RAINFALL WILL DECREASE EARLY
SUNDAY MORNING AS THE DISTURBANCE EXITS EAST AND DRIER AIR ALOFT
INCREASES.
KEY MESSAGE 2...
THERE IS THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS SUNDAY
AFTERNOON AND EVENING AS A TROUGH AND ASSOCIATED COLD FRONT
QUICKLY MOVE ACROSS THE GREAT LAKES. MACHINE-LEARNING GUIDANCE
INDICATES A 5-15% CHANCE OF SEVERE WEATHER FOR A PORTION OF OUR
REGION. LONG-RANGE ENSEMBLES SUPPORT 50-60% JOINT PROBABILITIES
OF EFFECTIVE SHEAR ABOVE 30KTS AND CAPE VALUES ABOVE 500J/KG
DURING THE AFTERNOON AND EVENING HOURS, WITH HIGHEST
PROBABILITIES NOTED NORTH OF PITTSBURGH WHERE STRONGER VERTICAL
WIND SHEAR RESIDES.
IF THE SYSTEM CONTINUES TO EVOLVE FAVORABLY ACROSS THE REGION,
ALL SEVERE WEATHER THREATS, INCLUDING DAMAGING WINDS, HAIL, AND
TORNADOES, WILL BE POSSIBLE.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
A WEAK SHORTWAVE WILL CONTINUE TO PRODUCE LIGHT RAIN SHOWERS
SOUTH OF AGC EARLY THIS MORNING. ZZV AND MGW HAVE THE GREATEST
POTENTIAL FOR MEASURED PRECIP. ELSEWHERE, PASSING HIGH CLOUDS
WILL CONTINUE TO LIMIT RADIATIONAL COOLING AND REDUCE THE
POTENTIAL OF DENSE WIDESPREAD FOG EARLY BEFORE 13Z. IF FOG DOES
DEVELOP, FKL MAY EXPERIENCE A BRIEF PERIOD OF VIS IMPACTS AS
CLEARING ON SATELLITE IMAGERY SLOWLY SHIFTS INTO NORTHWESTERN
PA.
DRIER CONDITIONS ARE EXPECTED TO DEVELOP BETWEEN 13Z TO 16Z
TODAY AS HIGH PRESSURE BUILDS INTO THE REGION. WINDS WILL
GENERALLY BE LIGHT FROM THE EAST, VFR CONDITIONS WILL MOSTLY
LIKELY PREVAIL INTO THE LATE EVENING.
AFTER 12Z SATURDAY, ANOTHER DISTURBANCE WILL LIFT NORTHWARD FROM
THE SOUTH AND INTO THE REGION, BRINGING RENEWED CHANCES OF RAIN
SHOWERS, THUNDERSTORMS, AND RESTRICTIONS. VIS RESTRICTIONS FROM
HEAVIER RAINFALL RATES ARE POSSIBLE, PARTICULARLY EAST OF HLG
BETWEEN 18Z TO 23Z SATURDAY.
OUTLOOK...
RESTRICTIONS WILL LIKELY CONTINUE INTO EARLY SUNDAY WITH
ADDITIONAL ROUNDS OF RAIN SHOWERS AND THUNDERSTORMS WITH A
PASSING FRONT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...HEFFERAN
AVIATION...HEFFERAN
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