417
FXUS61 KPBZ 010708
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
308 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 /07Z WEDNESDAY THROUGH SUNDAY/
A CROSSING COLD FRONT WILL RESULT IN SHOWERS AND THUNDERSTORMS
OVERNIGHT, TRENDING SOUTH WITH THE FRONTAL BOUNDARY, DOWN TO
NORTH OF MGW BY THE MORNING. CAN'T RULE OUT SOME EMBEDDED
THUNDERSTORMS EARLY IN THE AM WITH FRONTAL PASSAGE, AS THERE MAY
BE SOME LINGERING ELEVATED INSTABILITY. HOWEVER, THE SEVERE
THREAT IS MINIMAL AS LAPSE RATES AND DEEP- LAYER SHEAR HAVE
WEAKENED.
THE FRONT IS FORECAST TO STALL ROUGHLY NEAR THE PA/WV BORDER
THIS MORNING. NORTH OF THE FRONT, WINDS SHIFT TO NORTHWESTERLY
AND RAIN IS LIKELY TO CONTINUE, BUT GENERALLY WITH DECREASING
INTENSITY. CLOSER TO THE FRONT (NAMELY AT MGW), HEAVIER SHOWERS
AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO CONTINUE OR
REDEVELOP ON WEDNESDAY IN THE VICINITY OF THE PSEUDO STATIONARY
BOUNDARY.
LATEST ENSEMBLE GUIDANCE INDICATES SATURATED LOW LEVELS
MAINTAINING CIG RESTRICTIONS THROUGH THE TAF PERIOD WITH PORTS
OUTSIDE OF MGW AND ZZV SHOWING A 100% CHANCE OF MVFR CIGS AND
50 TO 100% CHANCE OF IFR CIGS PIT AND NORTH.
ONE AREA OF UNCERTAINTY IS WITH VIS RESTRICTIONS, AS ENSEMBLES
SHOW MINIMAL VIS RESTRICTIONS AND LAMP GUIDANCE SHOWS IFR
RESTRICTIONS. HAVE SPLIT THE DIFFERENCE FOR NOW BUT MAY NEED TO
INCREASE FORECAST VISIBILITIES IN FUTURE UPDATE.
OUTLOOK...
THE MENTIONED FRONT WILL TRANSITION NORTH AS A WARM FRONT
WEDNESDAY NIGHT INTO THURSDAY WITH RESTRICTIONS AND RAIN.
ANOTHER CROSSING COLD FRONT WILL MAINTAIN RESTRICTION AND RAIN
POTENTIAL LATE THURSDAY NIGHT THROUGH SATURDAY AS IT STALLS
ACROSS THE REGION.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...CL
AVIATION...88
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