503
FXUS61 KPBZ 231119
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
719 AM EDT THU JUL 23 2026
WHAT HAS CHANGED
NO MAJOR CHANCES TO THE FORECAST IN THE NEAR-TERM. SEVERE
WEATHER POTENTIAL CONTINUES TO BE SUNDAY INTO TUESDAY.
KEY MESSAGES
1) SEVERE WEATHER AND HEAVY RAINFALL POSSIBLE SUNDAY THROUGH
TUESDAY WITH A PATTERN SHIFT
DISCUSSION
KEY MESSAGE 1...
CONFIDENCE REMAINS HIGH THAT DRY AND COOL CONDITIONS WILL
PREVAIL THROUGH AT LEAST SATURDAY AFTERNOON UNDER HIGH PRESSURE
AND NORTHWEST FLOW. THERE IS THE POTENTIAL FOR A FEW ISOLATED
POP UP SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON ON THE
LEADING EDGE OF WARM, MOIST ADVECTION AS FLOW SHIFTS FROM THE
SOUTHWEST. BRIEF PERIODS OF LIGHTNING WOULD BE THE MAIN HAZARD.
THE THREAT FOR SEVERE THUNDERSTORMS IS EXPECTED TO RETURN EARLY
NEXT WEEK AS A RIDGE AXIS STRENGTHENS OVER THE CENTRAL CONUS AND
A LARGE-SCALE LOW INTENSIFIES NORTH OF ONTARIO. THE EVOLVING
SYNOPTIC PATTERN FAVORS UPSTREAM MESOSCALE CONVECTIVE SYSTEM
(MCS) DEVELOPMENT UPSTREAM OVER THE NORTHERN GREAT LAKES, WITH
SUBSEQUENT PROPAGATION INTO THE REGION OR REDEVELOPMENT ALONG
REMNANT OUTFLOW BOUNDARIES AND RESIDUAL CONVECTIVE FEATURES.
IF A MESOSCALE CONVECTIVE SYSTEMS (MCSS) DOES DEVELOP AND TRACK
INTO OUR REGION, FORECAST SOUNDINGS INDICATE AN ENVIRONMENT
CAPABLE OF SUPPORTING ALL SEVERE WEATHER HAZARDS, INCLUDING
HAIL, DAMAGING WIND GUSTS, TORNADOES, AND HEAVY RAINFALL.
HOWEVER, THE POTENTIAL FOR LARGE HAIL MAY BE LIMITED BY A WARM
FREEZING LEVEL (ABOVE 14KFT), PROMPTING THE MELTING OF HAIL
STONES.
NCAR MACHINE-LEARNING GUIDANCE CONTINUES TO INDICATE A 5-30%
PROBABILITY OF SEVERE THUNDERSTORMS FROM SUNDAY THROUGH TUESDAY
ACROSS THE OHIO RIVER VALLEY. COLORADO STATE UNIVERSITY (CSU)
MACHINE LEARNING HAS 5-15% CHANCE OF EXCESSIVE RAINFALL (FLASH
FLOODING) SUNDAY AND MONDAY AND SHIFTS THE POTENTIAL MOSTLY
SOUTH OF AREA BY TUESDAY. THE EVENTUAL EVOLUTION OF THIS THREAT
WILL LARGELY DEPEND ON THE AMPLITUDE OF THE EASTERN U.S. TROUGH
AND THE STRENGTH AND POSITION OF THE UPPER- LEVEL RIDGE, WHICH
WILL INFLUENCE THE TRACK AND INTENSITY OF ANY MCSS.
AVIATION /12Z THURSDAY THROUGH MONDAY/
MORNING RIVER VALLEY FOG IS BRINGING LIFR CONDITIONS TO HLG AND
SAW A BRIEF STINT OF MVFR VIS AT FKL. THESE RESTRICTIONS CAN
CONTINUE FOR ANOTHER HOUR OR TWO BEFORE FOG IS EXPECTED TO LIFT
AND MIX OUT. THEN, CONFIDENCE IS HIGH THAT PROLONGED VFR
CONDITIONS WILL OCCUR FOR A NUMBER OF DAYS UNDER HIGH PRESSURE.
WINDS WILL BE LIGHT AND VARIABLE TODAY WITH LITTLE CLOUD
COVERAGE.
OUTLOOK... VFR IS EXPECTED THROUGH SATURDAY UNDER HIGH
PRESSURE. SHOWER AND THUNDERSTORM CHANCES RETURN ON SUNDAY AND
MONDAY WITH AN APPROACHING COLD FRONT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...HEFFERAN
AVIATION...AK
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