285
FXUS61 KPBZ 270620
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
220 AM EDT MON APR 27 2026
WHAT HAS CHANGED
UPDATED FOR THE 00Z TAF ISSUANCE.
KEY MESSAGES
1) RAIN/THUNDERSTORM CHANCES RETURN TUESDAY AND WEDNESDAY.
2) BELOW-AVERAGE TEMPERATURES AND FROST/FREEZE CONDITIONS
RETURN EARLY MAY.
DISCUSSION
KEY MESSAGE 1...
SURFACE LOW PRESSURE, CURRENTLY DEEPENING OVER THE SOUTHERN
PLAINS, WILL LIFT NORTHWARDS ACROSS THE MIDWEST TODAY AND INTO
THE WESTERN GREAT LAKES TONIGHT AS SURFACE HIGH PRESSURE RIDGES
DOWN THE EASTERN SEABOARD. SHOWERS AND PERHAPS ISOLATED
THUNDERSTORMS ARE EXPECTED TO RETURN TO THE AREA TUESDAY MORNING
WITH AN ASSOCIATED WARM FRONT. THE MORNING SURFACE INVERSION
WILL LIKELY KEEP EARLY SHOWERS AND STORMS ELEVATED. MODEST MID-
LEVEL LAPSE RATES COULD SUPPORT SMALL HAIL FROM THESE ELEVATED
STORMS, BUT TRENDS ARE LESS FAVORABLE FOR THIS. WEAK INSTABILITY
THROUGH MOST OF THE DAY WILL LIMIT OVERALL THUNDER CHANCE AND
KEEP THE SEVERE THREAT TO A MINIMUM. A FEW ISOLATED
THUNDERSTORMS MAY DEVELOP ALONG THE COLD FRONT IN THE LATE
AFTERNOON WITH MAXIMIZED CAPE AND FRONTOGENETIC LIFT FOR HELP,
BUT ACTIVITY IS LIKELY TO BE LIMITED.
A SECOND DISTURBANCE WILL DEVELOP OVER THE LOWER MISSISSIPPI
VALLEY TUESDAY AND LIFT INTO THE OHIO VALLEY LATE TUESDAY NIGHT.
THIS WILL BRING ANOTHER ROUND OF SHOWERS WEDNESDAY MORNING, WITH
ISOLATED THUNDERSTORM CHANCES IN THE AFTERNOON/EARLY EVENING.
SEVERE POTENTIAL ON WEDNESDAY REMAINS LOW, HOWEVER, SOME SMALL
HAIL AND MODERATELY GUSTY WINDS CANNOT BE RULED OUT.
OF THE TWO SYSTEMS, WEDNESDAY IS EXPECTED TO BE THE WETTER PERIOD.
THE PROBABILITY OF OF RECEIVING MORE THAN A HALF INCH OF RAIN
IS AROUND 60%-80% ACROSS MUCH OF THE REGION ON WEDNESDAY,
COMPARED TO LESS THAN 40% ON TUESDAY. OVERALL STORM TOTALS FOR
THE TWO DAYS RANGE FROM ABOUT 0.9" ACROSS SOUTHERN PORTIONS OF
THE AREA TO AROUND 1.5" ALONG PORTIONS OF THE I-80 CORRIDOR.
THESE HIGHER TOTALS ARE DUE TO SLOWER PROGRESSION OF THE TROUGH
ON WEDNESDAY AFTERNOON, WITH LINGERING SHOWERS AND POSSIBLE
THUNDERSTORMS MAINLY NORTH OF PITTSBURGH DURING THE LATE
AFTERNOON HOURS.
KEY MESSAGE 2...
CONFIDENCE REMAINS HIGH IN A COOL START TO MAY AS DEEP GREAT
LAKES/NORTHEAST TROUGHING PROMOTES COLD ADVECTION UNDER
NORTHWESTERLY FLOW ALOFT. LOW TEMPERATURES FRIDAY, SATURDAY, AND
SUNDAY MORNINGS MAY BE AS COLD AS 10 DEGREES BELOW AVERAGE,
RESULTING IN WIDESPREAD 30S. THE RISK FOR FROST AND/OR FREEZING
CONDITIONS IS INCREASING FOR PORTIONS OF THE REGION, ESPECIALLY
ALONG THE RIDGES AND NORTH OF PITTSBURGH. FROST OR FREEZE
HEADLINES MAY BE NEEDED FOR THESE AREAS FRIDAY THROUGH SUNDAY.
AVIATION /06Z MONDAY THROUGH FRIDAY/
VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24 HOURS UNDER HIGH
PRESSURE. WINDS WILL GENERALLY PREVAIL FROM THE EAST/SOUTHEAST
BEFORE DAWN. WITH DIURNAL MIXING, WIND GUST ARE EXPECTED TO
INCREASING LATE MORNING AND INTO THE EVENING; AVERAGING NEAR
20KTS.
RAIN CHANCES RETURN ALONG A WARM FRONT TUESDAY MORNING; MAINLY
BETWEEN 10Z TO 13Z. CLOUDS WILL GRADUALLY LOWER TO MVFR
THROUGHOUT THE MORNING WITH INCREASING LOW-LEVEL MOISTURE. THERE
IS A SMALL CHANCE OF THUNDERSTORMS (10%) WITH THE PASSAGE OF
THE WARM FRONT. VFR CONDITIONS WILL LIKELY RETURN IN THE WAKE OF
TUESDAY AFTERNOON WITH INCREASING SUBSIDENCE.
OUTLOOK...
PERIODIC PRECIPITATION AND RESTRICTION CHANCES ARE THE MOST
LIKELY OUTCOME FOR THE REST OF THE WEEK AS THE WEATHER PATTERN
TRENDS TOWARD GREAT LAKES UPPER TROUGHING.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...RACKLEY
AVIATION...HEFFERAN/AK
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