961
FXUS61 KPBZ 272350
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
750 PM 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...
RIDGING OVER THE REGION WILL SHIFT TO THE EAST TODAY AS A
SURFACE LOW CROSSES THE NORTHERN GREAT LAKES. AN ASSOCIATED
WARM FRONT IS PROGGED TO LIFT ACROSS THE REGION TUESDAY
MORNING, BRINGING AREAWIDE SHOWERS AND POSSIBLY SOME ISOLATED
THUNDERSTORMS. LATEST NBM 6HR THUNDER PROBABILITIES ARE LARGELY
BETWEEN 10% AND 20% TUESDAY AND 20-40% WEDNESDAY AFTERNOON AND
SHOWER PROBABILITIES RANGE FROM 70-90% BOTH DAYS. ON TUESDAY,
FORECAST SOUNDINGS SUGGEST SHOWERS AND STORMS WILL BE ELEVATED
INITIALLY, AND RELATIVELY WEAK INSTABILITY THROUGH MOST OF THE
DAY WILL LIMIT OVERALL THUNDER CHANCES AND KEEP THE SEVERE
THREAT TO A MINIMUM. A FEW ISOLATED THUNDERSTORMS MAY DEVELOP
ALONG THE COLD FRONT IN THE LATE AFTERNOON/EVENING WITH
MAXIMIZED CAPE AND FRONTOGENETIC LIFT FOR HELP, BUT ACTIVITY IS
LIKELY TO BE LIMITED. DURING THE DAY, MOST OF THE REGION LOOKS
TO BE LARGELY CAPPED BY WARM AIR ALOFT.
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 /00Z TUESDAY THROUGH SATURDAY/
THE BEGINNING OF THE TAF PERIOD WILL FEATURE BKN LAYER HIGH
CLOUDS WITH SOME FEW CLOUD COVER LAYER IN THE MIDLEVELS.
SATURATION OF THE PROFILE WILL PROCEED OVERNIGHT WITH APPROACH
OF THE WARM FRONT. AS THIS HAPPENS VFR CONDITIONS WILL PREVAIL
MOST OF THE NIGHT EVEN AS SHOWERS DEVELOP TOWARDS DAWN. AS THE
PROFILE SATURATES, THE PROBS FOR MVFR CIGS INCREASE TO ABOUT
70% BETWEEN 14Z AND 20Z WITH SOME LINGERING CIGS. THE PROB FOR
IFR CIGS INCREASES TO ABOUT 60% BETWEEN 17Z AND 21Z AND HAVE
INCLUDED THAT IN SOME OF THE TERMINALS AS WELL. MOST LOCATIONS
ARE EXPECTED TO IMPROVE BY THE END OF THE TAF PERIOD.
THE WINDS ARE EXPECTED TO GUST TOWARDS DAWN FROM THE SOUTH UP TO
25 KNOTS IN SOME INSTANCES. WINDS THEN ARE EXPECTED TO DECREASE
A BIT THROUGH THE DAY AS THE MAIN JET CORE WOULD HAVE MOVED OUT
OF THE AREA BETWEEN 12Z AND 16Z.
OUTLOOK...
PERIODIC PRECIPITATION AND RESTRICTION CHANCES ARE THE MOST
LIKELY OUTCOME FOR THE REST OF THE WEEK AS THE PATTERN TRENDS
TOWARD PERSISTENT GREAT LAKES TROUGHING.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...RACKLEY/88
AVIATION...SHALLENBERGER
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