949
FXUS61 KPBZ 221649
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1249 PM EDT SAT AUG 22 2026
WHAT HAS CHANGED
NO MAJOR CHANGES HAVE BEEN MADE TO THE FORECAST OVERALL. THERE
IS STILL DECENT CONFIDENCE IN THE TIMING AND SCOPE OF
THUNDERSTORM ACTIVITY THIS AFTERNOON AND EVENING. STILL, THERE
RISK FOR HEAVY RAIN/FLOODING HAS INCREASED SLIGHTLY, MAINLY
NORTH OF I-80.
KEY MESSAGES
1) INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS THIS
AFTERNOON MAY LEAD TO SCATTERED INSTANCES OF DAMAGING WIND
GUSTS, WITH HAIL BEING A SECONDARY THREAT.
2) A MARGINAL RISK FOR DAMAGING WIND SUNDAY IS TIED TO AFTERNOON
AND EVENING CONVECTION NEAR THE I-80 CORRIDOR.
3) OUTSIDE OF LINGERING SHOWERS MONDAY NEAR LAKE ERIE, DRY
WEATHER FAVORED THROUGH MID NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...
PLENTY OF SUNSHINE ACROSS THE UPPER OHIO VALLEY IS ALLOWING
DESTABILIZATION TO TAKE PLACE AHEAD OF A MCV TRACKING ACROSS
SOUTHERN OHIO. THIS WILL PROVIDE THE SUPPORT FOR LIFT ALONG WITH
AN ADVANCING PREFRONTAL TROUGH. BY 18Z, MLCAPE INCREASES INTO
THE 1000-1500 J/KG RANGE AT LEAST ACCORDING TO RAP/REFS. THIS
BUOYANCY WILL ALLOW CONVECTION TO INCREASE IN COVERAGE DURING
THE EARLY TO MIDDLE AFTERNOON HOURS. CAMS CONTINUE TO SUPPORT
THESE IDEAS, WITH THE STRONGER CONVECTION MOVING EAST OF THE
REGION BY 02Z-03Z, WITH A FEW LINGERING SHOWERS CROSSING WITH
THE MAIN SURFACE COLD FRONT SHORTLY THEREAFTER.
THE MAIN SEVERE RISK REMAINS DAMAGING GUSTS. DCAPE IS STILL
PEGGED TO REMAIN IN THE 600-800 J/KG RANGE AND THUS BE
MARGINALLY FAVORABLE FOR DOWNBURSTS, AND THE BEST
0-6KM/EFFECTIVE SHEAR REMAINS FURTHER DOWN THE OHIO VALLEY. SO,
WE ARE LIKELY NOT LOOKING AT A HIGHER-END THREAT. STILL, WITH
INITIAL DISCRETE STORMS LIKELY TO CONGLOMERATE OVER TIME IN
MULTICELL CLUSTERS/SHORT LINES, ENOUGH COLD POOL CONSOLIDATION
MAY OCCUR TO CREATE SOME SCATTERED INSTANCES OF 55-65 MPH WIND
GUSTS GIVEN THE HEALTHY MLCAPE EXPECTATIONS. LARGE HAIL WOULD BE
A SECONDARY THREAT GIVEN THE RELATIVELY WEAK SHEAR AND MID-
LEVEL LAPSE RATES, BUT MAY BE POSSIBLE IN THE STRONGEST STORMS.
DOWNPOURS/LOCALLY HEAVY RAINFALL TOTALS REMAIN POSSIBLE AS WELL,
BUT THE HREF SUGGESTS THE GREATEST QPF POTENTIAL LIES JUST TO
OUR NORTH AND WEST CLOSER TO LAKE ERIE, AND MUCH OF THE I-80
CORRIDOR HAS HIGHER FLASH FLOOD GUIDANCE VALUES THAN TO THE
SOUTH. PRECIPITABLE WATER VALUES ARE NOT EXCESSIVELY HIGH
(75-85TH PERCENTILE) AS WELL. WILL CONTINUE TO MONITOR, BUT WILL
HOLD OFF ON A FLOOD WATCH FOR NOW.
KEY MESSAGE 2...
MID-LEVEL TROUGHING AND COLD ADVECTION LINGERS OVER THE REGION
ON SUNDAY, WHICH MAY SUPPORT ISOLATED/SCATTERED SHOWER AND
THUNDERSTORMS DEVELOPMENT DURING THE PEAK HEATING HOURS OF
SUNDAY, MAINLY NORTH OF I-70. ALTHOUGH DECREASING OVERALL
MOISTURE DEPTH SHOULD KEEP A CAP ON COVERAGE, ONE OR TWO STRONG
TO SEVERE STORMS MAY BE POSSIBLE GIVEN THE COOLING TEMPERATURES
ALOFT, IF AROUND 1000 J/KG OF SURFACE-BASED CAPE CAN DEVELOP AS
HI-RES MODELS SUGGEST.
KEY MESSAGE 3...
SHOWERS MAY LINGER NORTH OF I-80 AND ALONG THE RIDGES (A COOL-
SEASON TYPE OF SETUP) INTO MONDAY MORNING WITH ONGOING COOL
NORTHWEST FLOW OVER A WARM LAKE ERIE.
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 /18Z SATURDAY THROUGH THURSDAY/
HIGH CONFIDENCE FORECAST SHOWERS AND STORMS IMPACTING AIRPORTS. THE
BEST TIME WINDOW APPEARS 21Z-01Z. IT WILL BE A FEW HOURS
EARLIER FOR ZZV.
VFR PREVAILS UNTIL 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. BASED
ON THE LATEST HIGH RESOLUTION MODELS, THE TIME WINDOW IS 18-22Z
IN OHIO, 21-01Z PA AND WV SAVE FOR DUJ WHERE IT IS UNTIL 2Z.
LINGERING SHOWER AND LOW PROBABILITY THUNDERSTORMS EVENTUALLY
CLEAR EAST BY 06Z, BUT COOL ADVECTION PLUS RESIDUAL MOISTURE
FAVORS MVFR/IFR STRATUS DEVELOPMENT THEREAFTER. CURRENT PROBS
HAVE LOWERED TO A 20-30% OF IFR CIGS OVER PA AND WV. THE
HIGHEST CONFIDENCE NOW IS OUR HISTORICALLY MORE FREQUENT
TERMINALS OF FKL AND DUJ. HAVE ENOUGH CONFIDENCE TO ADD IFR CIGS
AT DUJ OVER NIGHT, BUT NO WHERE ELSE, SO KEPT THEM AT MVFR.
THE EASTERN TERMINALS OF LBE, MGW, AND DUJ MAY KEEP STRATOCU
MOST OF THE MORNING, WHICH WILL BE TEETERING ON MVFR/VFR
THRESHOLD, OTHERWISE CAVU. ANY SHOWER OR STORM SUNDAY WILL HOLD
OFF UNTIL AFTER 18Z. THE HIGHEST PROB OF A SHOWER OR STORM WILL
BE ALONG AND NORTH OF I80 IN PA SUNDAY AFTERNOON.
OUTLOOK...
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...CL
AVIATION...MCMULLEN/FRAZIER
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