182
FXUS61 KPBZ 041947
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
347 PM EDT FRI APR 4 2025
SYNOPSIS
AN ACTIVE PATTERN CONTINUES THROUGH THE WEEKEND WITH MULTIPLE
ROUNDS OF SHOWERS AND THUNDERSTORMS. SEVERE STORMS WILL BE
POSSIBLE SATURDAY.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- FLOOD WATCH REMAINS IN EFFECT FOR PORTIONS OF THE REGION.
- SHOWERS AND THUNDERSTORMS RESUME TONIGHT.
-
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A BRIEF LULL IN ACTIVITY CONTINUES THIS AFTERNOON AS THE MAIN
AXIS OF PRECIPITATION REMAINS SOUTH OF THE AREA ALONG A STALLED
FRONTAL BOUNDARY. AREAL FLOODING FROM OVERNIGHT RAINFALL HAS
MOSTLY SUBSIDED GIVEN DAYTIME DRY CONDITIONS. HOWEVER,
ADDITIONAL RAINFALL OVERNIGHT AND SATURDAY WILL EXACERBATE
ALREADY WET CONDITIONS, AND WILL LIKELY LEAD TO ADDITIONAL AREAS
OF FLOODING. A FLOOD WATCH REMAINS IN EFFECT FOR THE SOUTHERN
HALF OF THE AREA THROUGH SUNDAY MORNING.
AREAS ALONG AND NORTH OF I-80 SAW PATCHY SUNSHINE LATE THIS
MORNING INTO THE AFTERNOON AS THE LOWER CLOUD DECK SHIFTED TO
THE SOUTH. THIS ALLOWED TEMPERATURES NORTH OF PITTSBURGH TO RUN
SEVERAL DEGREES WARMER THAN SOUTHERN PORTIONS OF THE AREA.
HOWEVER, LOWER CLOUDS ARE BEGINNING TO MOVE BACK INTO THE AREA,
CUTTING OFF MUCH ADDITIONAL HEATING.
UPPER LEVEL HEIGHT RISES ARE EXPECTED THIS AFTERNOON AS A LARGE
UPPER LOW DIGS SOUTH OF THE FOUR CORNERS REGION AND A LARGE
500MB HIGH MOVES OVER THE SOUTHEASTERN US. THE RIDGING WILL PUSH
THE SURFACE HIGH TO THE NORTHEAST AND ALLOW THE STALLED FRONT
TO BEGIN TO SLOWLY MOVE NORTHWARD FROM THE MID-ATLANTIC REGION
AS EVENING APPROACHES. ANOTHER SURFACE LOW IS THEN EXPECTED TO
TRACK NE OUT OF THE MISSISSIPPI VALLEY REGION OVERNIGHT. THIS
WILL ALLOW SHOWERS (AND PERHAPS A RUMBLE OF THUNDER) TO LIFT
NORTHWARDS LATER THIS AFTERNOON AND INTO THE OVERNIGHT. CAMS ARE
FAIRLY SPARSE IN COVERAGE DURING THE AFTERNOON, BUT SHOW BETTER
ORGANIZATION AFTER MIDNIGHT WITH CROSSING WARM FRONT. A FEW
OVERNIGHT STORMS MAY BECOME SEVERE, AND SPC HAS MAINTAINED A
MARGINAL RISK OF SEVERE WEATHER FOR LOCATIONS WEST OF
PITTSBURGH, PRIMARILY FOR HAIL AND DAMAGING WIND.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
KEY MESSAGES:
- ROUNDS OF SHOWERS AND THUNDERSTORMS CONTINUE INTO THE WEEKEND.
- A FLOOD WATCH REMAINS IN EFFECT FOR PORTIONS OF THE REGION.
- SEVERE WEATHER IS POSSIBLE SATURDAY.
- A COLD FRONT ON SUNDAY WILL FINALLY BRING AN END TO THE HEAVY
RAINFALL THREAT.
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ANOTHER ROUND OF CONVECTION WILL CROSS THE AREA AROUND AND AFTER
SUNRISE SATURDAY MORNING WITH THE CROSSING WAVE. ENVIRONMENTAL
PARAMETERS WILL MAINTAIN A MARGINAL SEVERE THREAT, AGAIN
PRIMARILY FOR WIND AND HAIL. SOME CLEARING IS POSSIBLE BY LATE
MORNING/EARLY AFTERNOON AS THIS SHIFTS EAST, SETTING THE STAGE
FOR ANOTHER ROUND LATER SATURDAY AFTERNOON AND EVENING AHEAD OF
THE COLD FRONT.
CAMS HAVE BACKED OFF A BIT ON SEVERE POTENTIAL SATURDAY
AFTERNOON/EVENING WITH THE FRONT, WITH THE THREAT CONTINGENT ON
LATE MORNING CLEARING AND DESTABILIZATION. EARLIER RUNS
HIGHLIGHTED POSSIBLE DISCRETE CELLS AHEAD OF THE FRONT, WHICH
WOULD ENHANCE THE SEVERE RISK, BUT THE TREND HAS BEEN TOWARDS A
MORE LINEAR MODE AND LOWER PROBABILITIES FOR DESTABILIZATION.
STILL, IF STORMS ARE ABLE TO ORGANIZE IN THE LATE AFTERNOON,
HODOGRAPHS ARE SUPPORTIVE OF AT LEAST A MARGINAL TORNADO THREAT.
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO SATURDAY NIGHT AND
EARLY SUNDAY AS LOW PRESSURE CROSSES, BUT THE STALLED FRONT
REMAINS. RAPID HEIGHT FALLS ON SUNDAY WILL FINALLY SHUNT THE
SURFACE RIDGE OVER THE SOUTHEAST AND ALLOWING A COLD FRONT TO
CROSS THE AREA BY SUNDAY NIGHT/EARLY MONDAY -- FINALLY BRINGING
AN END TO WIDESPREAD RAINFALL. AS TEMPERATURES COOL BEHIND THE
FRONT, LINGERING PRECIPITATION MAY BRIEFLY TRANSITION TO SNOW
FOR AREAS NORTH OF PITTSBURGH AND IN THE RIDGES SUNDAY AFTERNOON
AND OVERNIGHT. GIVEN THE WARM/WET GROUND, ANY ACCUMULATION WILL
BE MINIMAL.
FLOODING POTENTIAL REMAINS HIGHEST ON SATURDAY WITH REPEATED
ROUNDS OF HEAVY RAINFALL ON AN ALREADY SATURATED GROUND. AN
ADDITIONAL 1-2 INCHES IS EXPECTED ACROSS MUCH OF THE AREA FROM
LATE TONIGHT THROUGH SUNDAY, WITH HEAVIEST PERIODS EXPECTED LATE
SATURDAY NIGHT AND EARLY SUNDAY. RISES ARE EXPECTED ON AREA
RIVERS.
LONG TERM /MONDAY THROUGH THURSDAY/
KEY MESSAGES:
- COLDER NEXT WEEK WITH LIGHT RAIN/SNOW CHANCES EARLY WEEK.
- DRY WEATHER BRIEFLY RETURNS MIDWEEK BEFORE ADDITIONAL
PRECIPITATION CHANCES BY LATE WEEK.
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WEAK SURFACE LOW PRESSURE, CROSSING OUT OF THE GREAT LAKES WILL
AID IN STRONG NORTHWESTERLY FLOW BEHIND THE FRONT MONDAY INTO
TUESDAY. THIS COULD BRING A FEW ADDITIONAL SHOWERS TO THE
REGION MONDAY INTO TUESDAY.
UPPER TROUGHING IS EXPECTED TO PERSIST THROUGH MIDWEEK,
RESULTING IN BELOW NORMAL TEMPERATURES. DRY WEATHER LOOKS TO
RETURN BRIEFLY MIDWEEK WITH HIGH PRESSURE BEFORE ADDITIONAL RAIN
CHANCE WITH A SYSTEM LATE WEEK.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
FOR THE REST OF THE DAY TODAY, A RETURN OF MOSTLY DRY AND VFR
CONDITIONS IS FAVORED FOR MOST. THE ONLY CHANCES OF MVFR LINGER
AROUND 50% FOR ZZV AND MGW CLOSER TO THE STALLED FRONT. DURING
FRIDAY AFTERNOON, EXPECT THE CHANCE FOR RAIN TO RETURN TO THE
REGION AS THE FRONT SURGES NORTH AGAIN. THE MARGINAL CHANCE FOR
THUNDERSTORMS INCREASE DURING THE EVENING WITH LOW ELEVATED
INSTABILITY, WHICH WILL ALSO BRING THE INCREASED PROBABILITY FOR
THE RETURN OF MVFR FOR A MAJORITY OF PORTS. NO MENTIONS WERE
MAINTAINED FOR NOW WITH PROBABILITIES BELOW 30%. RESTRICTIONS
ARE EXPECTED TO LINGER THROUGH SATURDAY WITH MORE CHANCES OF
RAIN, THOUGH CHANCES OF MVFR REMAIN HIGHEST FOR ZZV, FKL, AND
DUJ AT ROUGHLY 70%.
OUTLOOK... THE UPPER OHIO RIVER VALLEY WILL REMAIN POSITIONED
BETWEEN A MOUNTAIN WEST TROUGH AND EAST COAST RIDGE THAT WILL FOSTER
MULTIPLE ROUNDS OF MODERATE TO LOCALLY HEAVY RAIN THROUGH SUNDAY.
TIMING AND SHAPE IN EACH SHORTWAVE REMAINS VARIABLE, WHICH MAY ALTER
THE AXIS OF HIGHEST PRECIPITATION RATES AND AREAS OF GREATEST
RESTRICTIONS. AVIATION CUSTOMERS SHOULD ANTICIPATE LIMITED WINDOWS
OF VFR AND DRY CONDITIONS THROUGH THE PERIOD AS THE PATTERN FAVORS
MVFR/IFR RESTRICTIONS, HEAVIER RAIN SHOWERS AND OCCASIONAL
THUNDERSTORMS.
A DEEPENING UPPER LEVEL TROUGH IS LIKELY TO OVERTAKE THE REGION
MONDAY, SHIFTING TOWARDS A COLDER PATTERN FEATURING PERIODIC
RAIN/SNOW CHANCES AND CONTINUED CEILING RESTRICTIONS. BY MID-WEEK,
THE TROUGH IS EXPECTED TO MOVE OUT OF THE REGION AS A RIDGE BUILDS
IN. THIS WILL LIKELY RESULT IN REDUCED RESTRICTIONS.
HYDROLOGY
THE POTENTIAL FOR HEAVY RAINFALL WILL EXIST THROUGH SUNDAY. AT
THIS TIME, AREAS ACROSS OHIO HAVE THE POTENTIAL TO SEE THE
HEAVIEST RAINFALL, WHERE A FLOOD WATCH CONTINUES. CURRENT NBM
VALUES INDICATE A 70 PERCENT CHANCE OR GREATER OF AT LEAST 2
INCHES OF RAIN OVER A 72 HR PERIOD IN THIS REGION. LESSER
PROBABILITIES EXIST FURTHER EAST, THOUGH A TREND UP HAS BEEN
NOTED IN THE LATEST ENSEMBLE GUIDANCE AND WILL NEED TO BE
MONITORED FOR ANY POTENTIAL EXPANSION OF THE FLOOD WATCH. THE
EXACT LOCATION OF THE HEAVIEST RAIN WILL DEPEND ON THE POSITION
OF A QUASI-STATIONARY SURFACE FRONT. PRECIPITABLE WATER IS
EXPECTED TO REMAIN ELEVATED THROUGH SUNDAY, WITH SOME PERIODIC
JET ENHANCED ASCENT. EVEN AFTER THE HEAVY RAIN POTENTIAL ENDS,
RIVER LEVELS WILL LIKELY REMAIN ELEVATED FOR A FEW DAYS. CURRENT
ENSEMBLE RIVER FORECAST PROJECTIONS ALSO FOCUS THE MOST
SIGNIFICANT RIVER RISES ACROSS OHIO.
WILL MONITOR FURTHER TRENDS FOR ANY FUTURE ADJUSTMENTS TO THE
WATCH.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...FLOOD WATCH THROUGH SUNDAY MORNING FOR PAZ021-029-031-073>076.
OH...FLOOD WATCH THROUGH SUNDAY MORNING FOR OHZ039-040-048>050-
057>059-068-069.
WV...FLOOD WATCH THROUGH SUNDAY MORNING FOR WVZ001>004-012-021-509-
510.
SYNOPSIS...RACKLEY
NEAR TERM...RACKLEY
SHORT TERM...RACKLEY
LONG TERM...RACKLEY/22
AVIATION...WM
HYDROLOGY...
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