858
FXUS61 KPBZ 220616
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
216 AM EDT SAT AUG 22 2026
WHAT HAS CHANGED
HIGHER CONFIDENCE IN THE TIMING AND SCOPE OF THUNDERSTORM
ACTIVITY THIS AFTERNOON AND EVENING RESULTS IN HIGHER
PROBABILITY OF SEVERE WEATHER OCCURRING.
KEY MESSAGES
1) A SLIGHT RISK EXISTS FOR DAMAGING WIND AND LARGE HAIL THREAT
WITH STORM ACTIVITY THIS AFTERNOON AND EVENING.
2) OUTSIDE OF LINGERING SHOWERS NEAR LAKE ERIE, DRY WEATHER
FAVORED THROUGH MID NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...
OUTSIDE OF A LONER, ELEVATED STORM IN NORTH CENTRAL OH, THE
OVERNIGHT PERIOD HAS SEEN THE PRE-FRONTAL CONVECTION DIE OFF
EAST OF THE REGION WHILE THE MCS REMAINS FARTHER WEST IN CENTRAL
IL. THIS RESULTS SETS UP THE REGION TO REMAIN IN A CLEARER SKY
ENVIRONMENT THAT AWAITS THE ARRIVAL OF THE PRE-FRONTAL TROUGH
(AND EVENTUAL SFC COLD FRONT) TO INITIATE FAIRLY WIDESPREAD
SHOWERS AND THUNDERSTORMS. HI-RES GUIDANCE HAS GENERALLY
COALESCED AROUND THE IDEA OF STORM INITIATION BETWEEN 2PM-4PM
OVER EASTERN OH WITH STORMS SPREADING EAST THROUGH 8PM
ALONG/AHEAD OF THE PRE-FRONTAL TROUGH BEFORE LINGERING SHOWERS
AND LOW PROBABILITY THUNDERSTORMS FULL PUSH EAST OF THE REGION
BY THE EARLY HOURS SUNDAY MORNING AHEAD OF THE SURFACE COLD
FRONT.
CLEARER SKIES ALLOWING FOR MAXIMIZATION OF SURFACE HEATING
SHOULD PUSH AREA SBCAPE VALUES TOWARDS 1500-2000 J/KG AND
STEEPENS LOW-LEVEL LAPSE RATES THAT SERVES AS THE MAIN DRIVERS
FOR THE HAZARDOUS WEATHER THREAT. DESPITE WEAK SHEAR (AROUND
20KTS) AND MARGINAL DCAPE (600-800 J/KG) THAT SHOULD LIMIT THE
HIGH-END SEVERE POTENTIAL, DISCRETE STORMS THAT MERGE INTO
MULTICELLULAR CLUSTERS IS ENOUGH TO CREATE SCATTERED INSTANCES
OF DAMAGING WINDS AND LARGE HAIL. SEVERE THREATS PEAK BETWEEN
4PM-8PM BEFORE SUBSIDING THEREAFTER AS BUOYANCY WANES AND THE
SURFACE DECOUPLES.
CONVECTIVE ACTIVITY DOES LINGER OVERNIGHT SATURDAY UNTIL THE
SURFACE COLD FRONT COMPLETES ITS PASSAGE, AT WHICH POINT BRIEF
SUBSIDENCE/DRY ADVECTION REDUCES RAIN CHANCES. HOWEVER,
TRANSITION TO COOL ADVECTION WITHIN NW PLUS RESIDUAL SHORTWAVE
MOVEMENT TAPS INTO LAKE ERIE MOISTURE TO CREATE ISOLATED TO
SCATTERED NON-SEVERE CONVECTION THROUGH THE DAY SUNDAY THAT
FAVORS NORTHWEST PA.
KEY MESSAGE 2...
RESIDUAL COOL NORTHWEST FLOW ON THE BACKSIDE OF THE UPPER TROUGH
MAY INDUCE ENOUGH LIFT IN CONJUNCTION WITH WARM LAKE ERIE WATERS
TO CREATE LIGHT RAIN SHOWERS NEAR/NORTH OF I-80 LATE SUNDAY INTO
MONDAY.
OTHERWISE, HIGH PRESSURE AND HEIGHT RISES ALOFT POINT TO A
PROLONGED (RELATIVELY SPEAKING, IN RELATION TO THE PREVIOUS
MONTH) DRY PERIOD TO START NEXT WEEK. HIGH TEMPERATURE DOES
START BELOW SEASONAL AVERAGES ON MONDAY BEFORE RISING BACK NEAR
AVERAGE BY MID WEEK. LONG RANGE ENSEMBLES CURRENTLY FAVOR
THURSDAY AS THE NEXT DAY WITH SHOWERS/THUNDERSTORMS AS THE NEXT
UPPER TROUGH CROSSES.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
LIMITED EARLY MORNING FOG MAINLY WITHIN RIVER VALLEYS WILL ERODE
WITH DIURNAL HEATING/MIXING AFTER 12Z.
VFR PREVAILS OTHERWISE UNTIL FAIRLY WIDESPREAD SHOWERS AND
THUNDERSTORMS DEVELOP THIS AFTERNOON AND EVENING AHEAD OF AN
ADVANCING PRE-FRONTAL TROUGH (1ST) AND COLD FRONT (2ND) COMBO.
THE STRONG STORMS COULD DROP VISIBILITIES TO IFR LEVELS WHILE
ALSO POSING A RISK FOR CREATING WIND GUSTS TO AT LEAST 30KTS,
POTENTIALLY HIGHER.
LINGERING SHOWER AND LOW PROBABILITY THUNDERSTORMS EVENTUALLY
CLEAR EAST BY 06Z, BUT COOL ADVECTION PLUS RESIDUAL MOISTURE
FAVORS MVFR/IFR STRATUS DEVELOPMENT THEREAFTER.
OUTLOOK...
WIDESPREAD MVFR TO IFR CIGS ARE FAVORED SUNDAY MORNING THAT
IMPROVE THROUGH THE DAY, BUT SCATTERED SHOWERS AND LOW
PROBABILITY THUNDERSTORMS DEVELOP BY THE AFTERNOON DUE TO COOL
NW FLOW OVER WARM LAKE WATERS.
PRECIPITATION CHANCES LINGER IN NORTHWEST PA INTO MONDAY BEFORE
HIGH PRESSURE PROVIDES AREAWIDE VFR DRY WEATHER BY TUESDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...FRAZIER
AVIATION...FRAZIER
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