913
FXUS61 KPBZ 011130
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
730 AM EDT WED APR 1 2026
WHAT HAS CHANGED
SEVERE WEATHER CONCERNS HAVE ENDED FOR THE OVERNIGHT/MORNING
PERIOD, BUT REMAIN FOR THIS AFTERNOON AND EVENING, WITH A
MARGINAL (LEVEL 1 OF 5) RISK OF SEVERE STORMS FROM PITTSBURGH ON
SOUTH. CHANCES OF WIDESPREAD HEAVY RAIN DURING THE
THURSDAY/FRIDAY PERIOD HAVE DECREASED, BUT AT LEAST ISOLATED
HYDROLOGIC CONCERNS CANNOT BE RULED OUT THROUGH THE WEEKEND.
KEY MESSAGES
1) A SLOW-MOVING COLD FRONT WILL STALL NEAR THE PENNSYLVANIA
AND WEST VIRGINIA BORDER ON WEDNESDAY. ROUNDS OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED, WITH ISOLATED SEVERE STORMS POSSIBLE
ALONG AND AHEAD OF THE BOUNDARY THIS AFTERNOON AND EVENING.
2) ROUNDS OF SHOWERS AND STORMS WILL CONTINUE INTO THE UPCOMING
WEEKEND, WITH HEAVY RAIN/FLASH FLOODING CONCERNS LIKELY TO
REMAIN ISOLATED. A COLD FRONTAL PASSAGE BRINGS ANOTHER SEVERE
CHANCE SATURDAY, WITH COOLER AND QUIETER WEATHER TO FOLLOW.
DISCUSSION
KEY MESSAGE 1...
AS OF 3 AM, THE MAIN SURFACE COLD FRONT REMAINS OFF TO THE
NORTHWEST TOWARDS THE LAKE ERIE SHORE, BUT AN OUTFLOW BOUNDARY
FROM THE EARLIER CONVECTION IS BISECTING THE CWA, LAYING JUST
SOUTH OF ALLEGHENY COUNTY. SOME GENERALLY MODERATE TO BRIEFLY
HEAVY RAIN SHOWERS CONTINUE AHEAD OF THE MAIN FRONT, WITH 30-40
KNOTS OF 850MB FLOW CONTINUING TO SUPPORT LIFT. THE PRE-FRONTAL
ENVIRONMENT IS CHARACTERIZED BY 1.1-1.2 INCH PRECIPITABLE
WATER, WHICH IS AT OR ABOVE 95TH PERCENTILE FOR THE REGION. SO,
SHOWERS WILL BE EFFICIENT RAIN PRODUCERS, BUT WITH THE WANING OF
BUOYANCY, EXCESSIVE RAINFALL RATES ARE BECOMING LESS LIKELY.
OVERALL FLASH FLOOD CONCERNS ARE WANING, ALTHOUGH RAIN TOTALS
WILL CONTINUE TO BE MONITORED OVERNIGHT FOR ANY POTENTIAL
LONGER-TERM OVERFLOW ISSUES AND/OR URBAN AREA PROBLEMS.
THE MAIN FRONT WILL SETTLE INTO THE REGION THROUGH THE MORNING
HOURS, BEFORE STALLING IN THE VICINITY OF THE PA/WV BORDER THIS
AFTERNOON. THE AIRMASS ALONG AND AHEAD OF THE BOUNDARY WILL
REMAIN FAVORABLE FOR THUNDERSTORM DEVELOPMENT, WITH THE FRONT
ACTING AS A FOCUS FOR INITIATION. HREF PROGS INDICATE AROUND
600-800 J/KG OF MIXED- LAYER CAPE GENERALLY SOUTH OF I-70 THIS
AFTERNOON, ALONG WITH 35-40 KNOTS OF 0-6KM SHEAR. COMBINED WITH
STEEP LOW-LEVEL LAPSE RATES, SOME POTENTIAL FOR ISOLATED
DAMAGING WIND GUSTS EXISTS IN ANY CLUSTERS/LINE SEGMENTS THAT
CAN FORM. LARGE HAIL IS POSSIBLE GIVEN THE SHEAR, BUT MID-LEVEL
LAPSE RATES WILL BE MARGINAL AT BEST, IN THE 6-6.5C/KM RANGE.
ANY MODEST TORNADO POTENTIAL GENERALLY LIES SOUTH OF THE MASON-
DIXON LINE, WHERE SURFACE- BASED BUOYANCY WILL BE RICHER.
MACHINE-LEARNING GUIDANCE GENERALLY AGREES WITH THIS THINKING.
KEY MESSAGE 2...
500MB HEIGHTS ARE EXPECTED TO SLOWLY RISE OVER THE UPPER OHIO
VALLEY TONIGHT INTO THURSDAY IN RESPONSE TO TROUGHING OVER THE
NORTHERN PLAINS AND THE UPPER MISSISSIPPI VALLEY. THIS WILL HELP
TO PUSH THE STALLED BOUNDARY NORTHWARD AS A WARM FRONT. THIS
PUSH MAY SLOW NEAR THE RIDGES AS AN EASTERN CANADA SURFACE HIGH
INDUCES A COLD AIR DAMMING-LIKE SETUP OVER CENTRAL
PENNSYLVANIA. ADDITIONAL SHOWERS AND STORMS WILL OCCUR DURING
THIS PROCESS BUT HEAVY RAIN POTENTIAL APPEARS FAIRLY LOW; EVEN
90TH PERCENTILE HREF 24-HOUR RAIN TOTALS ENDING AT 8 PM
THURSDAY ARE GENERALLY AN INCH OR LESS. POOR LAPSE RATES AND
DEEP SHEAR MOSTLY UNDER 30 KNOTS WILL REDUCE THE POTENTIAL FOR
ORGANIZED SEVERE CONVECTION.
SCATTERED SHOWERS AND STORMS WILL REMAIN POSSIBLE THROUGH
FRIDAY, AGAIN WITH LOWER PROBABILITY OF WIDESPREAD HEAVY RAIN.
NBM 24-HOUR TOTALS THROUGH 8 PM FRIDAY TOP OUT AROUND 0.6 TO 0.7
INCH IN THE 90TH PERCENTILE. THAT SAID, WITH PRECIPITABLE WATER
REMAINING AT OR ABOVE THE 95TH PERCENTILE, ISOLATED WATER ISSUES
CANNOT BE RULED OUT IN ANY CONVECTIVE ELEMENTS. THE NEXT GOOD
POTENTIAL FOR WIDESPREAD SHOWER AND STORM ACTIVITY ARRIVES
SATURDAY/SATURDAY NIGHT, WITH LOW PRESSURE CROSSING THE GREAT
LAKES DRIVING THE NEXT COLD FRONT ACROSS THE REGION. DEPENDING
ON FRONTAL TIMING, A RISK OF SEVERE STORMS MAY ACCOMPANY THE
BOUNDARY; CSU AND NCAR LONGER-RANGE MACHINE LEARNING GUIDANCE
SUPPORT THIS THOUGHT. BEHIND THIS FRONT, A COOLER AND LESS-
ACTIVE WEATHER PATTERN TAKES HOLD, WITH TEMPERATURES DIPPING
BELOW CLIMATOLOGY BY SUNDAY NIGHT AND REMAINING THERE THROUGH
EARLY NEXT WEEK.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
THE AFOREMENTIONED FRONT IS CURRENTLY LOCATED BETWEEN BVI AND
UCP, WITH UCP'S WIND DIRECTION JUST GOING NORTHERLY ON THE
BACKSIDE. THE FRONT WILL CONTINUE SLOWLY MOVING SOUTHWARD
THROUGH THE REGION TODAY BEFORE STALLING SOMEWHERE BETWEEN THE
I-70 AND I-68 CORRIDORS.
SHOWERS CONTINUE TO MOVE EASTWARD ALONG AND SOUTH OF THIS
FRONT, BUT LIGHTNING HAS BEEN MINIMAL AND FOR LONG STRETCHES,
NONEXISTENT IN THIS ACTIVITY. SHOWERS ARE EXPECTED TO CONTINUE
THROUGH THE MORNING HOURS, BEFORE CAMS FAVOR SOME BREAKUP IN
COVERAGE AS WE NEAR MIDDAY.
CIGS ARE EXPECTED TO DEGRADE BEHIND THE FRONT, WITH IFR AND
LIFR PROBABILITIES RISING QUICKLY AND EASILY NOTED IN THE
OBSERVATIONS N AND W OF UCP. SOUTH OF THE BOUNDARY A MIX OF MVFR
AND VFR CONTINUES. AS THE BOUNDARY CONTINUES PRESSING
SOUTHWARD, THESE MVFR AND VFR DOMINOES ARE EXPECTED TO FALL. AT
THIS TIME, MGW STANDS THE BEST CHANCE OF REMAINING ABOVE IFR,
WITH THE LOWEST CHANCE TO SEE THE BOUNDARY CROSS OUR
SOUTHERNMOST PORT.
CLOUDS WILL NOT BREAK, BUT A BREAK IN SHOWERY ACTIVITY CAN
ALLOW FOR SOME WARMING SOUTH OF THE BOUNDARY THAT COULD ALLOW
FOR REPEATED ROUNDS OF THUNDERSTORMS MAINLY MOVING EASTWARD
ALONG THE STALLED BOUNDARY THIS AFTERNOON. STORMS LOOK MOST
LIKELY FOR MGW BUT ZZV COULD ALSO SEE A FEW RUMBLES OF THUNDER
THIS AFTERNOON.
THE FRONT IS EXPECTED TO MOVE NORTHWARD AGAIN THIS EVENING AND
POSSIBLY STALL ALONG THE EASTERN RIDGES INTO THURSDAY, ALLOWING
FOR CONTINUED SHOWER ACTIVITY.
OUTLOOK... RESTRICTION CHANCES CONTINUE THROUGH THURSDAY AND
FRIDAY WITH THE STALLED BOUNDARY. A CROSSING COLD FRONT SATURDAY
RETURNS SEVERE WEATHER CHANCES, BUT EVENTUALLY CLEARS THE
REGION OUT AND PROMOTES DRIER WEATHER BEHIND IT BEGINNING SUNDAY
AFTERNOON.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...CL
AVIATION...AK
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page