983
FXUS61 KPBZ 232347
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
747 PM EDT SUN AUG 23 2026
WHAT HAS CHANGED
NO MAJOR CHANGES TO THE FORECAST PACKAGE. AVIATION DISCUSSION
UPDATED FOR THE 00Z TAF ISSUANCE.
KEY MESSAGES
1) SCATTERED TO NUMEROUS SHOWERS AND A FEW THUNDERSTORMS THROUGH
THIS EVENING, MAINLY NORTH OF US-422, WITH VERY LOW SEVERE
WEATHER POTENTIAL.
2) MOSTLY DRY THROUGH WEDNESDAY. PRECIPITATION CHANCES INCREASE
THURSDAY, WITH SOME LOW-END POTENTIAL FOR SEVERE WEATHER
DEPENDING ON FUTURE MODEL TRENDS.
DISCUSSION
KEY MESSAGE 1...
UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN OVER FAR SOUTHERN
ONTARIO, WITH ASSOCIATED TROUGHING IN PLACE OVER THE EASTERN
GREAT LAKES AND THE UPPER OHIO VALLEY. TWO MAIN VORTICITY
MAXIMA ROTATE THROUGH THE FLOW INTO TONIGHT - ONE CLOSER TO THE
LAKE ERIE SHORELINE THIS AFTERNOON AND A MORE VIGOROUS ONE
DROPPING ACROSS OUR CWA THIS EVENING. THESE WILL BE RESPONSIBLE
FOR CONTINUING THE CHANCES FOR SCATTERED TO NUMEROUS, BUT BRIEF,
SHOWERS AND LOCALIZED THUNDERSTORMS THROUGH 06Z OR SO TONIGHT.
COVERAGE APPEARS BEST WITH THE SECOND WAVE, WITH MOST ACTIVITY
NORTH OF US-422. STILL, THUNDERSTORMS WILL BECOME A BIT LESS
LIKELY WITH THAT WAVE WITH DIURNAL STABILIZATION.
CHANCES OF STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING
REMAIN QUITE LOW OVERALL. WHILE SURFACE-BASED CAPE MAY PEAK IN
THE 1000-1200 J/KG RANGE THIS AFTERNOON, PARTICULARLY NORTH OF
I-80, DRIER AIR ABOVE 700MB SHOULD LIMIT UPDRAFT DEPTH, AND
0-6KM SHEAR OF LESS THAN 30 KNOTS WILL BE A DETRIMENT TO STORM
ORGANIZATION. ALONG WITH DOWNDRAFT CAPE VALUES OF 500 J/KG OR
LESS, THIS SUGGESTS THAT THE DAMAGING WIND THREAT IS VERY LOW.
HAIL MAY BE OBSERVED WITH A FEW OF THE MORE VIGOROUS CELLS, BUT
THE ABOVE PARAMETERS POINT TO DIAMETERS REMAINING BELOW SEVERE
LIMITS.
PRECIPITATION COVERAGE DROPS OFF AFTER 06Z WITH THE DEPARTURE OF
THE SECOND SHORTWAVE, BUT A FEW ISOLATED SHOWERS MAY CONTINUE
NORTH OF I-80 WITH CONTINUED NW FLOW OFF OF LAKE ERIE.
KEY MESSAGE 2...
LINGERING COOL ADVECTION WITHIN NORTHWEST FLOW RESULTS IN
HIGH TEMPERATURES AROUND 10 DEGREES BELOW THE DAILY AVERAGE
MONDAY WHILE HIGH PRESSURE SUPPORTS DRY WEATHER (SAVE FOR LOW
PROBABILITY SHOWERS NORTH OF I-80).
THE UPPER LOW LIFTS TOWARD QUEBEC BY TUESDAY, WHILE SURFACE HIGH
PRESSURE OVERSPREADS THE REGION. THIS CONTINUES DRY WEATHER
THROUGH WEDNESDAY, WHILE THE RISING 500MB HEIGHTS POINT TO
TEMPERATURES RISING BACK TO CLOSE TO SEASONABLE LEVELS.
THE NEXT TROUGH IS STILL PEGGED BY ENSEMBLES TO ARRIVE THURSDAY.
TIMING ISSUES THAT FAR OUT MEAN THAT THE HAZARD POTENTIAL IS
DIFFICULT TO ASCERTAIN CURRENTLY. LONG- RANGE MACHINE-LEARNING
GUIDANCE DOES SHOW A SLIGHT UPTICK IN SEVERE WEATHER POTENTIAL,
BUT THIS RISK WILL NEED MORE TIME AND MODEL CYCLES TO BE
PROPERLY EVALUATED.
AVIATION /00Z MONDAY THROUGH FRIDAY/
SCATTERED SHOWERS AND POTENTIALLY A FEW RUMBLES OF THUNDER MOVE
ACROSS THE AREA IN THE 00Z-06Z TIMEFRAME, WITH PROB30S AT ALL
TERMINALS EXCEPT FKL/DUJ WHERE HIGHER CONFIDENCE IN IMPACTS
FAVORS THE USE OF TEMPOS INSTEAD. BIGGEST IMPACTS FROM THESE
SHOWERS WILL BE REDUCED VISIBILITIES (GENERALLY MVFR/IFR) AND
POTENTIALLY SOME ERRATIC OUTFLOW WIND GUSTS IN THE 20-30 KNOT
RANGE. ONCE THESE SHOWERS DEPART THE AREA TO THE EAST, VFR IS
FAVORED EVERYWHERE EXCEPT DUJ OVERNIGHT INTO MONDAY.
DRY WEATHER AND WEST WINDS WITH OCCASIONAL GUSTS TO 18-23 KNOTS
ARE EXPECTED DURING THE DAY MONDAY.
OUTLOOK...
NO WIDESPREAD IFR WEATHER FORECAST THROUGH FRIDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...CL
AVIATION...CERMAK
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