592
FXUS61 KPBZ 281647
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1247 PM EDT SAT JUN 28 2025
SYNOPSIS
FLOODING AND ISOLATED DAMAGING WIND RISKS WILL BE POSSIBLE AHEAD
OF SLOW FRONT THIS AFTERNOON. PATCHY DENSE FOG IS POSSIBLE
OVERNIGHT INTO EARLY SUNDAY MORNING. DRIER WEATHER IS EXPECTED
SUNDAY, FOLLOWED BY ANOTHER ACTIVE PERIOD MONDAY TO TUESDAY.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR COUNTIES EAST
AND NORTHEAST OF PITTSBURGH UNTIL 8 PM EDT.
- DAMAGING WIND AND FLOODING THREATS IN THUNDERSTORMS TODAY
- DENSE FOG POTENTIAL INCREASES AFTER MIDNIGHT
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A WEAK FRONTAL BOUNDARY ADVANCING SOUTHEASTWARD THROUGH THE AREA
TODAY IS SERVING AS A FOCUS FOR THUNDERSTORM DEVELOPMENT, SOME
OF WHICH ARE PRODUCING DAMAGING WIND GUSTS, WITH REPORTS OF
NUMEROUS TREES DOWN ACROSS COUNTIES NORTH OF I-80 ALREADY
FLOWING IN. THUNDERSTORMS WILL CONTINUE TO FILL IN GENERALLY
ALONG AND EAST OF A LINE FROM FRANKLIN TO PITTSBURGH TO
WAYNESBURG IN WESTERN PA THROUGH THE EARLY AFTERNOON HOURS
BEFORE PUSHING EASTWARD TOWARDS CENTRAL PA BY LATE AFTERNOON AND
EVENING. THE ENVIRONMENT WILL CONTINUE TO SUPPORT A DAMAGING
WIND THREAT, WITH THE LATEST SPC MESOANALYSIS NOTING NEARLY 3000
J/KG SBCAPE EAST OF THIS LINE OF STORMS AS WELL AS 600-800 J/KG
DCAPE (SUPPORTING STRONG DOWNDRAFTS) AND ROUGHLY 20 KNOTS OF
DEEP LAYER SHEAR (ENOUGH TO SUPPORT SOME ORGANIZATION OF THE
STRONGEST STORMS). PRECIPITABLE WATER (PWAT) VALUES ALSO REMAIN
HIGH, WHICH INDICATES POTENTIAL FOR HEAVY DOWNPOURS AND
LOCALIZED FLASH FLOODING IN ANY LOCATIONS THAT SEE TRAINING
THUNDERSTORMS. WPC HAS MAINTAINED A MARGINAL RISK FOR EXCESSIVE
RAINFALL ACROSS MOST OF THE AREA.
THE PASSAGE OF THE BOUNDARY AND THE LOSS OF DAYTIME HEATING AND
INSTABILITY SHOULD LEAD TO DECREASING CONVECTIVE COVERAGE FROM
NORTH TO SOUTH DURING THE EVENING, WITH MOST OF THE AREA RAIN-
FREE BY MIDNIGHT. HOWEVER, WITH ABUNDANT RESIDUAL MOISTURE IN
THE BOUNDARY LAYER, CALM SURFACE WINDS AND SOME CLEARING SKIES
WILL INCREASE THE POTENTIAL FOR FOG DEVELOPMENT AFTER MIDNIGHT.
SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/
KEY MESSAGES:
- EARLY MORNING FOG SUNDAY
- MOSTLY DRY CONDITIONS SUNDAY
- STORM AND HEAVY RAINFALL CHANCES RETURN MONDAY AND TUESDAY.
- TEMPERATURES REMAIN ABOVE-AVERAGE, BUT BELOW HEAT ADVISORY
CRITERIA.
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FOG IS EXPECTED TO LINGER ACROSS THE REGION EARLY SUNDAY MORNING
THROUGH AT LEAST 8AM. THE FOG COULD BE DENSE AT TIMES AND MAY
PROMPT EITHER A SPECIAL WEATHER STATEMENT OR A DENSE FOG
ADVISORY.
THE COLD FRONT IS EXPECTED TO STALL JUST SOUTH OF THE MASON-
DIXON LINE ON SUNDAY, KEEPING MOST SHOWERS AND STORMS SOUTH OF
OUR AREA. THE EXCEPTION MAY BE A FEW SHOWERS/STORMS ACROSS THE
WV RIDGES SUNDAY AFTERNOON. TEMPERATURES WILL REMAIN ABOVE-
NORMAL UNDER INCREASINGLY ZONAL 500MB FLOW.
THE FRONT WILL BEGIN TO LIFT BACK NORTHWARD LATE SUNDAY NIGHT
INTO MONDAY, WITH SHOWERS LIKELY RETURNING TO THE AREA MONDAY
MORNING. ELEVATED PWATS WITH SOUTHWESTERLY FLOW AND PLENTIFUL
INSTABILITY WILL AGAIN MEAN FLOODING LOW-END SEVERE THREATS ARE
ON THE TABLE. WPC HAS MAINTAINED A MARGINAL RISK FOR EXCESSIVE
RAINFALL MONDAY/MONDAY NIGHT. RAIN WILL FINALLY CLEAR WITH
ANOTHER COLD FRONTAL PASSAGE TUESDAY, LEAVING DRIER CONDITIONS
FOR THE REMAINDER OF THE DAY. NORTHWESTERLY FLOW AND MEAGER COLD
ADVECTION WILL KEEP TEMPERATURES CLOSER TO SEASONAL NORMS
TUESDAY AFTERNOON.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
KEY MESSAGES:
- A DRIER AND MORE SEASONABLE AIR MASS ARRIVES BY WEDNESDAY AND
PERSISTS THROUGH AT LEAST THURSDAY.
-
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THE BREAK IN OUR MORE ACTIVE PATTERN CONTINUES WEDNESDAY INTO
THURSDAY AS TEMPERATURES RETURN TO A MORE SEASONABLE LEVEL UNDER
QUASI-ZONAL FLOW ALOFT. LOW PROBABILITY RAIN CHANCES MAY RETURN
THURSDAY AFTERNOON AND FRIDAY AS MORE WAVY MID-LEVEL FLOW
DEVELOPS. DETAILS AND TIMING REMAIN UNCLEAR AT THIS POINT.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
SHOWER AND THUNDERSTORM DEVELOPMENT IS EXPECTED MAINLY AFTER 18Z
AS A SLOW MOVING COLD FRONT ADVANCES FROM THE NORTH. HOWEVER,
STRAY SHOWERS CAN'T BE RULED EARLY THIS MORNING, TRIGGERED FROM
REMNANT OUTFLOW BOUNDARY OVER THE LAST 12 HOURS. HAVE PUT IN
SOME PROB30 TO ACCOUNT FOR THIS DEVELOPMENT INTO THE AFTERNOON
AT JUST ABOUT ALL THE TERMINALS. DEVELOPMENT SHOULD WANE AND
DISSIPATE BETWEEN 00Z TO 03Z.
WITH POTENTIAL CLEARING, LIGHT WINDS, AND AN ABUNDANT AMOUNT OF
REMNANT MOISTURE NEAR THE SURFACE THE POTENTIAL OF FOG INCREASES
ACROSS THE REGION. FOG COULD BE DENSE AT TIMES, MAINLY BETWEEN
THE TIME PERIOD OF 08Z TO 11Z. SURFACE HEATING WILL LIKELY HELP
IMPROVE VIS CONDITIONS AFTER 12Z.
PROBABILITY OF SHOWERS AND STORMS IS ELEVATED SOUTH OF HLG WITH
A STALLED FRONTAL BOUNDARY ON SUNDAY. OUT OF ALL THE TERMINALS,
MGW WOULD BE THE MOST LIKELY CANDIDATE TO EXPERIENCE A FEW
STRAY SHOWERS.
OUTLOOK... SHOWERS/STORMS RETURN AGAIN MONDAY WITH AN
APPROACHING COLD FRONT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...CERMAK/HEFFERAN
NEAR TERM...CERMAK/HEFFERAN
SHORT TERM...RACKLEY
LONG TERM...RACKLEY/CL
AVIATION...HEFFERAN/SHALLENBERGER
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