460
FXUS61 KPBZ 221200
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
800 AM EDT MON JUN 22 2026
WHAT HAS CHANGED
SEVERE THUNDERSTORM CHANCES HAVE INCREASED SLIGHTLY FOR TODAY,
AS THE SPC SLIGHT AND MARGINAL RISK AREAS HAVE EXPANDED A BIT
NORTHWEST. UNCERTAINTY REMAINS REGARDING WHERE THE AXIS OF
HEAVIEST RAINFALL SETS UP TODAY, BUT TRENDS INDICATE IT MAY BE
SOUTH OF PITTSBURGH, POTENTIALLY IN NORTHERN WEST VIRGINIA.
KEY MESSAGES
1) ROUNDS OF SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY
THROUGH THIS EVENING. RISKS FOR ISOLATED SEVERE THUNDERSTORMS
AND INSTANCES OF FLASH FLOODING REMAIN.
2) DRY CONDITIONS AND SEASONABLE TEMPERATURES ARE EXPECTED
THROUGH MIDWEEK.
DISCUSSION
KEY MESSAGE 1...
SURFACE LOW PRESSURE IS FORECAST TO RIDE FROM ILLINOIS UP THE
OHIO VALLEY TODAY, REACHING WESTERN PA BY 18Z. THIS WILL PUSH A
WARM FRONT INTO OUR REGION AHEAD OF THE LOW, BEFORE A FOLLOWING
COLD FRONT CROSSES DURING THE LATE AFTERNOON AND EVENING. LIGHT
RAIN HAS ALREADY SPREAD INTO WESTERN PARTS OF THE CWA, FED BY
WARM ADVECTION/ISENTROPIC LIFT AHEAD OF THE BOUNDARY. THIS RAIN
WILL CONTINUE TO SPREAD EASTWARD THROUGH THE MORNING, PERHAPS
WITH SLOWLY INCREASING RATES AS INCREASING MOIST ADVECTION
STARTS TO BRING HIGHER BUOYANCY/POTENTIAL FOR MORE CONVECTIVE
SHOWERS. RAIN TOTALS THROUGH 18Z ARE MOSTLY EXPECTED TO REMAIN
BELOW A HALF-INCH. THERE MAY BE A BRIEF RELATIVE BREAK IN
PRECIPITATION DURING THE MIDDAY HOURS, ESPECIALLY IN AREAS THAT
GET INTO THE WARM SECTOR.
THIS AFTERNOON, AS THE WARM FRONT MOVES NORTH, MOISTURE
MAXIMIZES IN AREAS SOUTH OF PITTSBURGH, WITH PRECIPITABLE WATER
MAXIMIZING IN THE 1.6 TO 1.8 INCH RANGE. DESPITE ABUNDANT CLOUD
COVER, SURFACE-BASED CAPE IS EXPECTED TO BUILD ABOVE 1000 J/KG
SOUTHEAST OF A ROUGH DUJ/PIT/ZZV LINE (40% OR GREATER CHANCE ON
HREF PROGS). EXPECTED 0-6KM SHEAR OF 30-35 KNOTS SHOULD BE
SUFFICIENT FOR STORM ORGANIZATION INTO CLUSTERS/LINES AHEAD OF
THE ADVANCING COLD FRONT. DAMAGING WINDS ARE THE MOST LIKELY
SEVERE THREAT IN THIS SCENARIO. A LOW TORNADO THREAT EXISTS
WHERE CONVECTION COULD POTENTIALLY TAKE ADVANTAGE OF LOCALLY
BACKED FLOW IN THE VICINITY OF THE WARM FRONT, MOST LIKELY
SOUTHEAST OF PITTSBURGH, WHERE THE SPC SLIGHT (LEVEL 2 OF 5)
RISK OF SEVERE THUNDERSTORMS EXISTS. MORE ISOLATED POTENTIAL
EXISTS IN THE REST OF THE CWA FOR DAMAGING GUSTS.
THE NOTED PRECIPITABLE WATER LEVELS SUGGEST EFFICIENT RAIN-
PRODUCING STORMS, AS DOES DECENT LOW-LEVEL SOUNDING SATURATION
AND WARM CLOUD DEPTHS. HOWEVER, STORM MOTION SHOULD HELP TO
LIMIT THE HEAVY RAIN THREAT TO SOME DEGREE. CAMS ARE ALSO STILL
IN DISAGREEMENT AS TO WHERE THE HEAVIEST CORRIDOR OF
PRECIPITATION MAY SET UP. REFS/HREF DO SUGGEST MAXIMUM TOTAL
RAINFALL POTENTIAL OF 2 TO 3 INCHES IN THE HEAVIEST CASES WHERE
TRAINING COULD OCCUR IN THE VICINITY OF THE WARM FRONT. SUCH
RAINFALL TOTALS COULD CAUSE LOCALIZED FLOOD ISSUES. HOWEVER,
GIVEN THE SPATIAL UNCERTAINTIES AND STORM MOTION, THINK THAT THE
THREAT REMAINS ISOLATED ENOUGH FOR NOW TO HOLD OFF ON A FLOOD
WATCH ISSUANCE. IF LATER CAM RUNS FOCUS HEAVY RAINFALL MORE
FAVORABLY ON A REGION (MOST LIKELY TARGET ZONE: NORTHERN WEST
VIRGINIA), THEN A SHORT-FUSE WATCH COULD BE CONSIDERED.
THE PASSAGE OF THE COLD FRONT TONIGHT SHOULD DECREASE COVERAGE
OF SHOWERS AND STORMS FROM WEST TO EAST, LIKELY PULLING OUT OF
THE SOUTHEASTERN RIDGES OVERNIGHT. A DEVELOPING SUBSIDENCE
INVERSION WILL LIKELY LOCK IN LOW-LEVEL MOISTURE, PRODUCING
STRATUS AND FOG LATE TONIGHT.
KEY MESSAGE 2...
HIGH PRESSURE BUILDS IN THE WAKE OF THE DEPARTING LOW, AND AFTER
A POTENTIALLY DREARY SUNRISE TUESDAY, DRY WEATHER AND A TREND
TOWARDS SEASONABLE TEMPERATURES IS EXPECTED THROUGH WEDNESDAY.
HIGH VALUES SHOULD REACH THE UPPER 70S TO AROUND 80 BY MIDWEEK.
AVIATION /12Z MONDAY THROUGH FRIDAY/
SHOWERS ARE CROSSING THE FORECAST AREA ARE CAUSING SOME MINOR
IMPACTS TO THE THIS MORNING. THERE IS EXPECTED TO BE A BREAK IN
PRECIP FOR MOST AREA DURING THE MID MORNING, ESPECIALLY FOR THE
WESTERN TERMINALS. SOME DEVELOPMENT OF THUNDERSTORMS ARE
POSSIBLE THROUGH THE LATE MORNING HOURS. A TEMPO GROUP WAS USED
FOR MOST TERMINALS IN THE 16Z TO 23Z TIME FRAMES TIMING THE
THUNDERSTORMS THROUGH THE DAY AS THEY CROSS THE FORECAST AREA.
THERE ARE SOME INSTANCES OF THUNDERSTORMS MOVING BACK INTO THE
AREA LATE BEFORE THE EVENT COMES TO AN END AND THIS WAS IN MGW
WHERE A LATE PROB30 WAS USED IN THE 23Z TO 02Z RANGE. WINDS ARE
EXPECTED TO BE SOUTHWEST THROUGH THE DAY AND A VRB20G30 WAS USED
FOR TSRA INSTANCES THROUGH THE AFTERNOON AND EVENING.
ACTIVITY WILL DECREASE FROM WEST TO EAST AFTER 00Z AS A COLD
FRONT CROSSES. HOWEVER, A DEVELOPING SUBSIDENCE INVERSION SHOULD
LOCK IN LOW-LEVEL MOISTURE, PRODUCING IFR CONDITIONS IN STRATUS
AND FOG AFTER SUNSET AND CONTINUING THROUGH THE NIGHT. THESE
RESTRICTIONS SHOULD BE IN PLACE THROUGH 12Z.
OUTLOOK...
VFR CONDITIONS ARE LIKELY TO RETURN TUESDAY AFTER THE MORNING
FOG AND STRATUS BURN OFF. THE NEXT CHANCE FOR WIDESPREAD
RESTRICTIONS WILL BE THURSDAY WITH INCREASED PRECIPITATION
POTENTIAL.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...CL
AVIATION...SHALLENBERGER
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