148
FXUS61 KPBZ 071729
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
129 PM EDT SUN AUG 7 2022
SYNOPSIS
SCATTERED THUNDERSTORMS, FAVORING THAT AFTERNOON TO EVENING
HOURS, ARE EXPECTED UNTIL A MID-WEEK COLD FRONT USHERS IN
COOLER, DRIER AIR AHEAD OF THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
THE REGION REMAINS WEDGED BETWEEN HIGH PRESSURE TO THE SOUTHEAST
AND A WEAK TROUGH OVER THE GREAT LAKES, WHICH IS HELPING TO
MAINTAIN THE FUNNELING OF MOIST GULF AIR INTO THE REGION.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THE
AFTERNOON WITHIN AN ENVIRONMENT HIGHLIGHTED BY ABNORMALLY HIGH
PWATS, WEAK SHEAR, AND WEAK FORCING. THE COMBINATION OF SLOWER
STORM MOTION AND HIGH RAINFALL RATES (1-2"/HR POSSIBLE) MEANS
THERE IS A THREAT FOR LOCALIZED FLOODING, BUT THE LACK OF
CONCENTRATED FORCING/LIFT AND ENOUGH FORWARD MOTION WILL LIMIT
THE THREAT FROM BEING WIDESPREAD AND PREVENT THE NEED FOR A
FLOOD WATCH.
ENOUGH SUBSIDENCE AND LOSS OF INSTABILITY WITH HEATING SHOULD
SEE CONVECTION DISSIPATE AFTER SUNSET, THOUGH AN ISOLATED SHOWER
CAN'T BE COMPLETELY RULED OUT OVERNIGHT. TEMPERATURE WILL REMAIN
WELL ABOVE NORMAL AMID WARM, MOIST ADVECTION.
SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/
A WEAK SHORTWAVE IS EXPECTED TO CROSS NORTH OF THE REGION MONDAY
WITHIN THE BROAD, WEAK ZONAL FLOW AS HIGH PRESSURE REMAINS TO
THE SOUTH. ENOUGH JET ASCENT WITH THIS TROUGH SHOULD CREATE A
MOST FOCUSED AREA FOR CONVECTION NORTH OF PITTSBURGH, WHILE ALSO
PROVIDING FASTER EASTWARD STORM MEAN FLOW. THE HUMID ENVIRONMENT
WILL REMAIN UNCHANGED OTHERWISE, MEANING ANOTHER AFTERNOON OF
SCATTERED CONVECTION THAT WILL POSE A LOCALIZED (BUT UNLIKELY
WIDESPREAD) FLOOD THREAT.
THE UPPER LEVEL PATTERN WILL BEGIN TO TRANSITION TUESDAY AS A
SERIES OF SERIES ACT TO FURTHER DEVELOP A TROUGH OVER THE GREAT
LAKES. THESE WAVES WILL HELP SLOWLY PUSH A SFC COLD FRONT
SOUTHEAST THROUGH THE REGION TUESDAY INTO WEDNESDAY (THOUGH
MODEL TIMING DOES VARY ON ITS PASSAGE). EXPECT GREATER
THUNDERSTORM COVERAGE ALONG AND AHEAD OF THE BOUNDARY GIVEN
STRONGER LIFTING FORCES FROM THE BOUNDARY AND UPPER JET. THERE
IS TOO MUCH MODEL VARIANCES TO NOTE ANY POTENTIAL SEVERE THREAT,
BUT LOCALIZED FLOODING GIVEN REMNANT HUMID AIR WILL REMAIN
POSSIBLE.
AFTER FRONTAL PASSAGE, COOLER AND DRIER AIR WILL FILTER IN FROM
THE NORTHWEST AND LOWER AREA TEMPERATURE/HUMIDITY READINGS WHILE
ENDING PRECIPITATION CHANCES.
LONG TERM /THURSDAY THROUGH SATURDAY/
A MORE POTENT COLD FRONT AND DEEPER TROUGH ARE EXPECTED TO
QUICKLY FOLLOW THE INITIAL FRONTAL PASSAGE WEDNESDAY, WITH
ENOUGH JET ASCENT AND COLD ADVECTION TO GENERATE ISOLATED TO
SCATTERED AFTERNOON STORMS THURSDAY.
AFTER ITS PASSAGE, THERE BECOMES HIGH CONFIDENCE IN HIGH
PRESSURE UNDER NW FLOW DEVELOPING OVER THE UPPER OHIO RIVER
VALLEY FOR THE WEEKEND. EXPECT SEASONABLE TEMPERATURE AND LOWER
HUMIDITY LEVELS THROUGH THAT PERIOD.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
DISORGANIZED SHOWERS AND THUNDERSTORMS WILL BE THE RULE DURING
THE AFTERNOON AND EARLY EVENING, IN AN ENVIRONMENT OF HIGH
MOISTURE BUT LITTLE ORGANIZED FORCING. HAVE USED VCTS IN MOST
CASES, ALTHOUGH EARLY TEMPOS WERE USED AT HLG AND LBE, WHERE
IMPACTS ARE IMMINENT. ANY STORM WILL BE CAPABLE OF IFR
VISIBILITY IN BRIEF DOWNPOURS. WILL NEED TO MONITOR FOR SHORT-
FUSED UPDATES THROUGH THE AFTERNOON.
CONVECTION WILL LARGELY DISSIPATE WITH THE LOSS OF HEATING
OVERNIGHT. THE OVERNIGHT FORECAST IS TRICKY, AND PARTIALLY
DEPENDS ON WHERE RAIN FALLS TODAY. MODEL SOUNDINGS/ENSEMBLE
GIVE BETTER CONFIDENCE IN LOW CLOUDS FROM PIT/AGC ON NORTH, AND
THIS IS WHERE MVFR CONDITIONS WERE INCLUDED IN THE HOURS
SURROUNDING SUNRISE.
VFR WILL RETURN BY LATE MORNING AT ALL TERMINALS, BUT AN
APPROACHING SHORTWAVE AND BUILDING INSTABILITY WILL ONCE AGAIN
START TO FIRE SHOWERS OFF DURING THE MIDDAY HOURS.
OUTLOOK
SCATTERED, MAINLY DIURNAL SHOWERS AND STORMS WILL CONTINUE TO BE
POSSIBLE ON TUESDAY. MORE WIDESPREAD RESTRICTIONS ARE EXPECTED
DURING THE MIDWEEK PERIOD WITH AN APPROACHING COLD FRONT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page