930
FXUS61 KPBZ 311104
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
704 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, LOWERED HIGH TEMPERATURES SLIGHTLY TODAY. ADJUSTED 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 /12Z MONDAY THROUGH FRIDAY/
VFR LIGHT RAIN SHOWERS/SPRINKLES EXPECTED THROUGH THE FIRST 6
HOURS OF THE TAF PERIOD AS EMBEDDED SHORTWAVES CROSS THE AREA.
MODEL CONSENSUS FAVORS VFR WITH DRY WEATHER THE REST OF THE
AFTERNOON AS SURFACE RIDGING ATTEMPTS TO BUILD FROM THE
SOUTHWEST, CONTINUING INTO TUESDAY.
HOWEVER, THOSE EMBEDDED SHORTWAVES AREN'T WELL MODELED AND
THEIR PRESENCE COULD RESULT IN ISOLATED/SCATTERED SHOWERS AND
THUNDERSTORMS IF/WHEN THEY CROSS THE AREA. CONFIDENCE ISN'T
HIGH ENOUGH IN THE OCCURRENCE/COVERAGE TO MENTION THUNDER, BUT
FKL/DUJ ARE THE MOST LIKELY TERMINALS TO SEE LATER AMENDMENTS
ADDING THUNDERSTORMS IN WITH AN INITIAL TIME FRAME GUESS OF
20Z-24Z.
OUTLOOK...
DURING NON-CONVECTIVE PERIODS WITH NO PRIOR RAIN OCCURRENCE, VFR
IS LIKELY UNDER THE INFLUENCE OF RIDGING TO THE SOUTHWEST.
SHORTWAVE MOVEMENT ALONG THE NORTHERN PERIPHERY OF THE RIDGE
COULD CREATE SHORT PERIODS THROUGH THE WEEK WHERE
SHOWERS/THUNDERSTORMS MAY OCCUR. DUE TO DIFFICULTIES MODELING
THESE FEATURES, TIMING/COVERAGE OF STORM POTENTIAL MAY BE
DIFFICULT UNTIL 6-12 HOURS BEFORE ARRIVAL AND CAUSE LARGER-
THAN-NORMAL FLUCTUATIONS IN TAF STORM TIMING. ADDITIONALLY,
STORM ENVIRONMENTS MAY BE CONDUCIVE TO GUSTY, ERRATIC WINDS PLUS
HEAVY DOWNPOURS THAT COULD CONTRIBUTE TO RESTRICTION
DEVELOPMENT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...WM
AVIATION...FRAZIER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page