389
FXUS61 KPBZ 231702
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
102 PM EDT SUN AUG 23 2026
WHAT HAS CHANGED
NO MAJOR CHANGES TO THE FORECAST PACKAGE ARE INDICATED.
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 /18Z SUNDAY THROUGH FRIDAY/
HIGH CONFIDENCE FORECAST OUTSIDE A FEW HOUR WINDOW THIS EVENING
WHERE VIS MAY DROP TO MVFR FROM HLG-LBE AND POINTS NORTH FROM A
SERIES OF UPPER DISTURBANCES.
FKL AND DUJ WILL SEE PASSING SHOWERS OFF OF LAKE ERIE THROUGH
THIS EVENING AS UPPER AIR IMPULSES TRAVERSE. IF THOSE AIRPORTS
ARE IMPACTED, MVFR VIS PERHAPS EVEN IFR VIS COULD OCCUR,
OTHERWISE EXPECT VFR WEATHER AREAWIDE. ONE FLY IN THE OINTMENT
WOULD BE CIGS DURING THE PREDAWN HOURS /9-13Z/ AT DUJ WHERE
PROBS OF CIGS < 1KFT RESIDE IN THE 30% RANGE. FOR NOW, GIVEN
CONTINUITY WITH THE LAMP GUIDANCE ELECTED TO CARRY IFR CLOUDS,
BUT THAT COULD CHANGE WITH FUTURE GUIDANCE.
HIGHEST CONFIDENCE OF AIRPORTS STAYING DRY THE ENTIRE FORECAST
ARE ZZV AND MGW. THERE IS A LOW PROB THAT THE TERMINALS FROM
WHEELING - PITTSBURGH - LATROBE COULD SEE SHOWERS BETWEEN 1-6Z,
SO ADDED PROB30S. KEPT THEM NO LOWER THAN MVFR WITH CIG AND VIS
PROBS LESS THAN 20% OF ATTAINING IFR NUMBERS.
GUSTY WEST WINDS WILL SUBSIDE WITH LOSS OF HEATING. WIND WILL
PICK BACK UP WITH SUSTAIN SPEEDS CLOSE TO 12 KNOTS FROM MIDDAY
MONDAY ON. GUSTS ARE NOT FORECAST TO BE AS HIGH MONDAY AS THEY
ARE TODAY.
OUTLOOK...
NO WIDESPREAD IFR WEATHER FORECAST THROUGH FRIDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...CL
AVIATION...MCMULLEN
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