795
FXUS61 KPBZ 280004
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
804 PM EDT MON JUL 27 2026
WHAT HAS CHANGED
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
1) SHOWERS AND THUNDERSTORMS AT TIMES THROUGH TONIGHT, WITH SOME
SEVERE AND LOCALLY HEAVY RAIN POTENTIAL
2) SHOWERS AND THUNDERSTORMS CONTINUE INTO TUESDAY, WITH
DECREASING SEVERE WEATHER POTENTIAL
3) SHOWERS DECREASING W-E WEDNESDAY AND THURSDAY, THEN MAINLY
DRY AND SEASONABLE THROUGH SATURDAY
DISCUSSION
KEY MESSAGE 1...
CONVECTION WAS DEVELOPING ACROSS THE GREAT LAKES REGION EARLY
THIS AFTERNOON, AND WILL CONTINUE TO TRACK SOUTHEASTWARD. THE
LATEST MESOANALYSIS SHOWS INCREASING DIURNAL INSTABILITY ACROSS
THE REGION, WITH ML CAPE RANGING FROM 1000-2000 J/KG. CAPPING
WAS OBSERVED ON THE 12Z PIT SOUNDING JUST UNDER 700MB, WHICH
WILL LIKELY INITIALLY LIMIT CONVECTIVE POTENTIAL ACROSS THE AREA
EARLY THIS AFTERNOON. SOME EROSION OF THE CAP IS EXPECTED
THROUGH THE DAY, THOUGH A WARM LAYER REMAINS AROUND 700MB
THROUGH EARLY THIS EVENING.
EXPECT SCATTERED CONVECTION TO DEVELOP ACROSS AREAS NORTH OF
I-70 THIS AFTERNOON AS CONVECTIVE TEMPERATURES ARE REACHED, AND
AS THE CAP SLOWLY ERODES. ADDITIONAL SHOWERS AND THUNDERSTORMS
COULD BECOME FOCUSED ALONG A LAKE BREEZE, AND WITH OUTFLOW FROM
CONVECTION UPSTREAM. SOME STORMS COULD CONTAIN DAMAGING WIND
GUSTS, WITH INCREASING SHEAR AND DRY MID LEVEL AIR. THE LATEST
DAY ONE OUTLOOK FROM THE STORM PREDICTION CENTER MAINTAINED A
SLIGHT RISK FOR SEVERE STORMS ACROSS NW PA INTO ERN OH, WITH A
MARGINAL RISK ELSEWHERE.
ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CROSS THE
UPPER OHIO VALLEY REGION TONIGHT AHEAD OF AN APPROACHING
SHORTWAVE TROUGH AND SURFACE COLD FRONT. A POTENTIAL MCS COULD
CLIP SOME OF THE OHIO COUNTIES LATER THIS EVENING AS WELL. THE
MOST FAVORABLE INSTABILITY (1500-2500 J/KG ML CAPE), AND SHEAR
(30-40KT) IS EXPECTED TO BE ACROSS OHIO, WITH LESSER VALUES TO
THE EAST. THIS LINES UP WELL WITH THE LATEST DAY ONE OUTLOOK
FROM SPC. THE SEVERE POTENTIAL SHOULD WANE SOMEWHAT OVERNIGHT,
THROUGH THERE SHOULD BE ENOUGH INSTABILITY TO MAINTAIN
THUNDERSTORMS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE IF ANY
TRAINING OCCURS, THOUGH THE LIMITED POTENTIAL AND UNCERTAINTY
PRECLUDES A FLOOD WATCH AT THIS TIME.
KEY MESSAGE 2...
EXPECT SOME ONGOING CONVECTION AND CLOUD COVER TUESDAY MORNING
AS THE COLD FRONT/SHORTWAVE CONTINUE TO APPROACH. INCREASING
INSTABILITY NEAR AND SE OF THE COLD FRONT SHOULD RESULT IN A
MARGINAL RISK OF SEVERE STORMS, MAINLY SOUTH OF A DUJ-BTP-ZZV
LINE. THE EXTENT OF ANY MORNING CONVECTION AND CLOUD COVER WILL
HAVE AN IMPACT ON THE AMOUNT OF INSTABILITY, AND RESULTING
SEVERE WEATHER POTENTIAL THROUGH THE DAY.
SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO DIMINISH BY EVENING AS
THE FRONT CROSSES AND BEGINS TO EXIT THE REGION, AND AS
INSTABILITY DECREASES.
KEY MESSAGE 3...
THE SHORTWAVE TROUGH IS PROGGED TO DEEPEN INTO AN UPPER LOW
ACROSS THE NE CONUS BY MID WEEK. WRAP AROUND MOISTURE AND LIFT
SHOULD RESULT IN SHOWER CHANCES CONTINUING EAST OF I-77 ON
WEDNESDAY, DECREASING FURTHER FROM W-E ON THURSDAY AS THE LOW
DRIFTS EASTWARD. SHORTWAVE RIDGING IS THEN PROGGED TO MOVE
ACROSS THE UPPER OHIO VALLEY REGION LATER THURSDAY THROUGH
SATURDAY, WITH DRY AND SEASONABLE WEATHER EXPECTED. THE NEXT
CHANCE FOR SHOWERS AND THUNDERSTORMS IS EXPECTED SATURDAY NIGHT
AND SUNDAY WITH THE NEXT APPROACHING SHORTWAVE TROUGH.
AVIATION /00Z TUESDAY THROUGH SATURDAY/
LINE OF CONVECTION APPROACHING THE OH/PA BORDER WILL MOVE EAST
THROUGH 03Z, LIKELY WEAKENING AS IT DOES SO. HAVE HANDLED THIS
LINE WITH BRIEF TEMPO IFR/MVFR VISIBILITY IN HEAVIER RAIN, BUT
DO NOT FORESEE SIGNIFICANT WIND GUSTS AT THIS TIME.
AFTER A LULL DURING THE LATE EVENING/EARLY OVERNIGHT, ADDITIONAL
CONVECTION IS LIKELY OVERNIGHT UNTIL AROUND SUNRISE AS A
SHORTWAVE TROUGH CROSSES. EXACT EVOLUTION OF THIS CONVECTION
REMAINS A BIT QUESTIONABLE, BUT WE HAVE GOOD CONFIDENCE THAT THE
MAIN MESOSCALE CONVECTIVE SYSTEM WILL TRACK TO OUR WEST, ACROSS
WESTERN OHIO. NEVERTHELESS, ONE OR MORE LINES OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED DURING THE PERIOD, WITH LIKELY
MVFR/IFR RESTRICTIONS. HAVE USED TEMPO GROUPS AT MOST TERMINALS
FOR THIS ACTIVITY. THE MAIN IMPACTS ARE LIKELY TO BE THE
DOWNPOURS AND SOME NON-SEVERE WIND GUSTS, PERHAPS IN THE 25 TO
35 MPH RANGE.
PAST THIS CONVECTION, MVFR/IFR CEILINGS AND MIST ARE POSSIBLE
FOR A FEW HOURS DURING THE MORNING. DIURNAL DESTABILIZATION
AHEAD OF AN APPROACHING COLD FRONT IS LIKELY TO PRODUCE AT LEAST
SCATTERED CONVECTION DURING THE AFTERNOON. AGAIN, COVERAGE AND
TIMING REMAIN LOW CONFIDENCE, AND HAVE USED PROB30 GROUPS TO
ILLUSTRATE THIS.
OUTLOOK...SHOWERS MAY LINGER IN THE POST-FRONTAL ENVIRONMENT
TUESDAY NIGHT DUE TO COLD NW FLOW ALOFT MAINTAINING SOME
BUOYANCY.
HIGH PRESSURE BUILDS THROUGH THE MID-WEEK PERIOD TO INCREASE THE
DURATION OF VFR PERIODS WITH DRY WEATHER, WITH ANY RESTRICTIONS
MAINLY OCCURRING DURING THE MORNING HOURS DUE TO LOW CLOUDS
AND/OR FOG.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...WM
AVIATION...CL
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page