389
FXUS61 KPBZ 310603
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
203 AM EDT MON AUG 31 2026
WHAT HAS CHANGED
CONTINUED TO INCREASE POPS FOR SHOWERS THIS MORNING ACROSS MUCH
OF THE AREA WITH CROSSING SHORTWAVES. WITH INCREASED CLOUD COVER
LOWER HIGH TEMPERATURES SLIGHTLY TODAY. ADJUST POPS HIGHER INTO
TUESDAY FOR POSSIBLE SHOWERS AND THUNDERSTORMS.
KEY MESSAGES
1) SCATTERED SHOWERS THIS MORNING, WITH ISOLATED
SHOWERS/THUNDERSTORMS THIS AFTERNOON.
2) ADDITIONAL SHOWER AND THUNDERSTORM CHANCES AT TIMES THROUGH
LATE WEEK, WITH SOME POSSIBILITY FOR SEVERE STORMS.
3) HEAT AND HUMIDITY BUILD THROUGH MID WEEK
DISCUSSION
KEY MESSAGE 1...
SCATTERED SHOWERS, MORE NUMEROUS NORTH OF PITTSBURGH, ARE
EXPECTED THIS MORNING, INITIALLY IN WARM ADVECTION ALONG A
SURFACE BOUNDARY ACROSS NORTHERN OHIO INTO NW PA. MESOANALYSIS
AND WATER VAPOR SATELLITE IMAGERY CURRENTLY SHOWS A VORT MAX
ACROSS THE NE INDIANA AREA. THIS SHOULD TRACK ESE ACROSS THE
REGION THROUGH THIS MORNING. ADDITIONAL SCATTERED SHOWERS ARE
EXPECTED TO DEVELOP AND TRACK ACROSS THE UPPER OHIO VALLEY
REGION THIS MORNING AS IT CROSSES.
ANOTHER VORT MAX IS PROGGED TO CROSS THE LOWER GREAT LAKES
REGION THIS AFTERNOON, WITH SCATTERED SHOWERS/STORMS NORTH OF
PIT, WHERE THE BEST LIFT AND MOISTURE IS PROGGED. BECOMING MORE
ISOLATED TO THE SOUTH. THIS ACTIVITY SHOULD WANE BY LATE
AFTERNOON AS THE WAVE EXITS.
KEY MESSAGE 2...
A RIDGE IS EXPECTED TO BUILD EASTWARD FROM THE CENTRAL CONUS
THROUGH MID WEEK. THE HIGHEST 500MB HEIGHTS ARE PROGGED TO BE
ACROSS THE UPPER OHIO VALLEY REGION ON WEDNESDAY. AS THE RIDGE
BUILDS EASTWARD, SHORTWAVES ARE EXPECTED TO TRACK ALONG THE
NORTHERN/NORTHEASTERN PERIPHERY OF THE RIDGE, CROSSING THE LOWER
GREAT LAKES/UPPER OHIO VALLEY REGION. OCCASIONAL SHOWER AND
THUNDERSTORM CHANCES ARE EXPECTED AS THESE WAVES CROSS, ONE
TONIGHT (MAINLY NORTH OF THE FORECAST AREA,) WITH ANOTHER
POSSIBLE LATER TUESDAY. THERE REMAINS UNCERTAINTY IN THE
PLACEMENT AND STRENGTH OF THE RIDGE, AND THE RESULTING TRACK OF
ANY SHORTWAVES ON THE NORTHERN PERIPHERY.
THERE IS A CONDITIONAL POTENTIAL FOR SEVERE STORMS ON TUESDAY.
ML CAPE INCREASES TO BETWEEN 2000 AND 3000 J/KG BY LATE
AFTERNOON, WITH VEERING IN THE LOW LEVELS. AN INITIAL WARM
LAYER ALOFT COULD LIMIT CONVECTION, THOUGH A POSSIBLE SHORTWAVE
PASSAGE IN THE AFTERNOON COULD TRIGGER THUNDERSTORMS. THIS
SCENARIO REMAINS UNCERTAIN DUE TO THE REASONS MENTIONED ABOVE,
THOUGH IF STORMS ARE ABLE TO DEVELOP SEVERE WEATHER WILL BE
POSSIBLE.
THE DAY WITH THE LOWEST POTENTIAL FOR SHOWERS AND THUNDERSTORMS
APPEARS TO BE WEDNESDAY, WHEN THE RIDGE IS PROGGED TO BE THE
STRONGEST ACROSS THE UPPER OHIO VALLEY REGION. CURRENT
INDICATIONS ARE THE RIDGE SHOULD BEGIN TO BREAK DOWN LATE
WEDNESDAY AND THURSDAY, AS A SHORTWAVE AND SURFACE COLD FRONT
APPROACHING. THE POTENTIAL FOR SEVERE STORMS WILL ALSO INCREASE
BY WEDNESDAY EVENING, INCREASING AGAIN ON THURSDAY AS CONVECTION
INCREASES IN DIURNAL HEATING ALONG THE SLOW MOVING FRONT.
INCREASING NW FLOW ALOFT SHOULD RESULT IN INCREASING SHEAR, AS
WELL AS INCREASING DIURNAL INSTABILITY. THE POTENTIAL CONTINUES
FOR SEVERE STORMS INTO THURSDAY. THE LATEST ML GUIDANCE
INDICATES THE INCREASING SEVERE POTENTIAL, ESPECIALLY LATE
WEDNESDAY AND THURSDAY. DEPENDING ON HOW FAST THE FRONT DRIFTS
SOUTH, THIS POTENTIAL COULD CONTINUE FOR AT LEAST SOUTHERN
PORTIONS OF THE AREA INTO FRIDAY. DRY WEATHER SHOULD RETURN BY
THE WEEKEND AS THE FRONT EXITS AND HIGH PRESSURE BUILDS IN.
KEY MESSAGE 3...
RISING 500MB HEIGHTS WITH THE BUILDING RIDGE SHOULD RESULT IN
WARMER TEMPERATURES EACH DAY THROUGH MID WEEK, WITH THE HEAT
PEAKING WEDNESDAY WHEN THE RIDGE IS STRONGEST ACROSS THE UPPER
OHIO VALLEY REGION. MOST LOCATIONS OUTSIDE OF THE HIGHER TERRAIN
SHOULD REACH THE 85 TO 90 DEGREE RANGE ON TUESDAY, THOUGH THERE
IS A CONTINUED POTENTIAL FOR CONVECTION AND/OR PATCHY CLOUD
COVER WHICH COULD AFFECT DAYTIME HIGHS. THE HEAT SHOULD PEAK
WEDNESDAY, AS HIGHS IN THE UPPER 80S TO LOWER 90S FOR MOST
AREAS. THE COMBINATION OF HEAT AND HUMIDITY SHOULD RESULT IN
HEAT INDEX VALUES IN THE MID TO UPPER 90S TUESDAY AND WEDNESDAY.
AVIATION /06Z MONDAY THROUGH FRIDAY/
SHOWERS IN WARM ADVECTION WERE TRACKING ACROSS PORTIONS OF THE
AREA THIS MORNING, MAINLY AFFECTING FKL AND DUJ. SOME TEMPO MVFR
RESTRICTIONS ARE LIKELY AS THESE SHOWERS MOVE THROUGH.
ELSEWHERE, A FEW SHOWERS ARE POSSIBLE, THOUGH CONDITIONS SHOULD
REMAIN VFR. A SHORTWAVE TROUGH IS EXPECTED TO CROSS THE REGION
LATER TONIGHT INTO MONDAY MORNING, WITH SCATTERED LIGHT SHOWERS
EXPECTED. EXPECT CONDITIONS TO REMAIN VFR AS THESE MOVE THROUGH.
THERE COULD BE AN AFTERNOON THUNDERSTORM IN SPOTS, THOUGH
PROBABILITY AND COVERAGE IS EXPECTED TO BE MINIMAL ENOUGH TO
PRECLUDE A TAF MENTION AT THIS TIME. EXPECT A SCATTERED CUMULUS
LAYER BY AFTERNOON, WITH MID LEVEL CLOUD CIGS ABOVE.
OUTLOOK...
MAINLY VFR IS EXPECTED THROUGH MID WEEK UNDER A BUILDING RIDGE,
THOUGH A FEW SHOWERS ARE POSSIBLE TONIGHT NORTH OF PIT AS A
SHORTWAVE CROSSES THE NORTHERN PERIPHERY OF THE RIDGE. ANOTHER
WAVE IS POSSIBLE TUESDAY AFTERNOON AND EVENING, WHICH COULD
TRIGGER SCATTERED THUNDERSTORMS. MAINLY DRY WEATHER IS EXPECTED
WEDNESDAY, BEFORE SHOWER AND THUNDERSTORM CHANCES RETURN
WEDNESDAY EVENING INTO FRIDAY AS A COLD FRONT DROPS SLOWLY
SOUTHWARD ACROSS THE REGION.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...WM
AVIATION...WM
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