441
FXUS61 KPBZ 311147
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
747 AM EDT FRI JUL 31 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST.
KEY MESSAGES
1) CONTINUED DRY THROUGH PART OF SATURDAY
2) SHOWERS AND THUNDERSTORMS RETURN LATE SATURDAY AND SUNDAY,
WITH UNSETTLED WEATHER NEXT WEEK
DISCUSSION
KEY MESSAGE 1...
DRY WEATHER IS EXPECTED THROUGH AT LEAST EARLY SATURDAY AS HIGH
PRESSURE MOVES EAST ACROSS THE REGION. RISING 500 MB HEIGHTS
UNDER SHORTWAVE RIDGING SHOULD RESULT IN HIGH TEMPERATURES NEAR
TO ABOVE SEASONABLE LEVELS TODAY. A DIGGING SHORTWAVE TROUGH IS
EXPECTED TO BEGIN TO ADVANCE OUT OF THE MIDWEST TONIGHT INTO
SATURDAY. EXPECT AN INCREASE IN MID AND HIGH LEVEL CLOUDS
TONIGHT THROUGH SATURDAY MORNING IN ADVANCE OF THE TROUGH.
KEY MESSAGE 2...
THE SHORTWAVE TROUGH IS EXPECTED TO CONTINUE TO DEEPEN AS IT
TRACKS TOWARD THE UPPER OHIO VALLEY REGION LATE SATURDAY AND
SUNDAY. AT THE SAME TIME, AN ASSOCIATED SURFACE LOW IS PROGGED
TO TRACK NE ACROSS THE UPPER OHIO VALLEY/EASTERN GREAT LAKES
REGION. INCREASING MOISTURE AND ASCENT WITH AN INITIAL LEAD
SHORTWAVE SHOULD RETURN SHOWER AND THUNDERSTORM CHANCES SATURDAY
AFTERNOON ACROSS OHIO, OVERSPREADING THE REMAINDER OF THE AREA
SATURDAY NIGHT.
PERIODS OF SHOWERS AND SCATTERED THUNDERSTORMS ARE EXPECTED ON
SUNDAY AS THE MAIN TROUGH AXIS APPROACHES, AND THE SURFACE LOW
TRACKS ACROSS THE REGION. CLOUDS COULD LIMIT INSTABILITY, WITH
ML CAPE CURRENTLY PROGGED AT 1000 J/KG OR LESS. MACHINE LEARNING
ALSO KEEPS CHANCES FOR SEVERE STORMS LOW, THOUGH SHEAR IS
EXPECTED TO INCREASE WITH INCREASING FLOW ALOFT. LOCALLY HEAVY
RAIN WILL ALSO BE POSSIBLE AS PWATS APPROACH 1.8 INCHES, THOUGH
SOME INDICATION OF A DRY SLOT SUNDAY AFTERNOON AHEAD OF THE
SURFACE LOW WOULD LIMIT THIS POTENTIAL. THE SURFACE COLD FRONT
IS CURRENTLY EXPECTED TO CROSS THE AREA LATE SUNDAY/SUNDAY
NIGHT.
MODEL ENSEMBLES THEN INDICATE A PERSISTENT TROUGH ACROSS THE
EASTERN GREAT LAKES AND OHIO VALLEY REGION EARLY IN THE WEEK.
THIS TROUGH SHOULD WEAKEN SOME THROUGH THE WEEK, THOUGH
SIGNIFICANT UNCERTAINTY EXISTS IN EXACT PLACEMENT AND STRENGTH.
OVERALL, EXPECT DAILY, DIURNALLY DRIVEN SHOWER AND THUNDERSTORM
CHANCES UNDER THIS PATTERN.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
HIGH CONFIDENCE VFR CONTINUES THROUGH THE TAF PERIOD AS SURFACE HIGH
PRESSURE SLIDES EAST ACROSS THE REGION. SCANT BOUNDARY LAYER
MOISTURE WILL PRECLUDE MORE THAN A FEW DIURNAL CUMULUS CLOUDS
THIS AFTERNOON GIVING WAY TO INCREASING HIGH CLOUDS LATER
TODAY/TONIGHT AHEAD OF THE NEXT APPROACHING SHORTWAVE TROUGH.
WIND WILL BE LIGHT AT 5 KNOTS OR LESS.
OUTLOOK...
VFR SHOULD CONTINUE INTO SATURDAY BEFORE RESTRICTION POTENTIAL
IN SHOWERS AND THUNDERSTORMS INCREASE FROM W-E LATE SATURDAY
THROUGH SUNDAY NIGHT WITH THE APPROACH AND PASSAGE OF A COLD
FRONT. A LINGERING TROUGH COULD MAINTAIN RESTRICTION POTENTIAL
MONDAY AND TUESDAY WITH SHOWER/THUNDERSTORM CHANCES, THOUGH MUCH
TIMING UNCERTAINTY ARISES INTO EARLY NEXT WEEK WITH EVOLUTION OF
THE TROUGH.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...WM
AVIATION...WM/MLB
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page