267
FXUS61 KPBZ 051520
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1120 AM EDT SAT APR 5 2025
SYNOPSIS
AN ACTIVE PATTERN CONTINUES THROUGH THE WEEKEND WITH MULTIPLE
ROUNDS OF SHOWERS AND THUNDERSTORMS. SEVERE STORMS ARE POSSIBLE
TODAY. MUCH COLDER TEMPERATURES NEXT WEEK.
NEAR TERM /UNTIL 6 PM THIS EVENING/
KEY MESSAGES:
- FLOOD WATCH REMAINS IN EFFECT FOR PORTIONS OF THE REGION.
- RISK FOR SHOWERS AND STORMS CONTINUE TODAY WITH A COLD FRONT.
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SURFACE LOW PRESSURE CENTERED NEAR THE WESTERN END OF LAKE ERIE
WILL CONTINUE TO RIDE NORTHEASTWARD TODAY ALONG A SLOWLY
ADVANCING COLD FRONT, WHICH WILL SLOWLY PUSH EASTWARD ACROSS
OHIO THIS MORNING AND INTO WESTERN PENNSYLVANIA THIS AFTERNOON.
THE WARM FRONT HAS PUSHED NORTH INTO THE I-80 VICINITY, WITH
SHOWERS BECOMING MORE SCATTERED BEHIND IT. THIS WILL LIKELY
REMAIN THE CASE UNTIL THE COLD FRONT APPROACHES LATER TODAY.
THE HEAVY RAIN THREAT WILL WANE TEMPORARILY UNTIL BETTER MID-
LEVEL FORCING ARRIVES TONIGHT.
THE SEVERE RISK LATER TODAY WILL DEPEND ON HOW MUCH LOW- LEVEL
INSTABILITY CAN DEVELOP THIS AFTERNOON, ESPECIALLY SOUTHEAST OF
PITTSBURGH WHERE BETTER EFFECTIVE SHEAR IS LIKELY TO SET UP. IF
SURFACE DEWPOINTS CAN RISE INTO THE LOWER 60S OR SO AND ENOUGH
CLOUD BREAKS PROVIDE A BIT OF SURFACE HEATING, PERHAPS AROUND
500 J/KG OF SBCAPE COULD DEVELOP, WHICH IN CONCERT WITH THE
SHEAR MAY BE ENOUGH FOR AT LEAST ISOLATED SEVERE STORMS CAPABLE
OF ALL HAZARDS. MESOSCALE TRENDS WILL BE MONITORED TO ASSESS
THIS THREAT.
EVEN THOUGH WE WILL HAVE CLOUDS AND RAIN, TEMPERATURES WILL BE
WELL ABOVE NORMAL TODAY.
SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/
KEY MESSAGES:
- A COLD FRONT ON SUNDAY WILL FINALLY BRING AN END TO THE HEAVY
RAINFALL THREAT.
- MUCH COLDER MONDAY WITH LATE DAY RAIN/SNOW SHOWERS.
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SHOWERS AND SOME THUNDERSTORMS WILL CONTINUE TONIGHT 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 ALLOW 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.
STRONG COLD AIR ADVECTION AND NORTHWEST FLOW MONDAY WILL PUSH
HIGH TEMPERATURES BACK DOWN TO BELOW NORMAL VALUES. SOME BRIEF
IMPROVEMENT IN OUR WEATHER IS POSSIBLE MONDAY AFTERNOON BEFORE A
SECOND COLD FRONT WILL BRING THE RISK FOR PRECIPITATION LATE IN
THE DAY.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
KEY MESSAGES:
- IMPRESSIVE COLD SHOT TUESDAY.
- DRY WEATHER BRIEFLY RETURNS MIDWEEK BEFORE ADDITIONAL
PRECIPITATION CHANCES BY LATE WEEK.
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COLDEST AIR WILL MOVE THROUGH THE REGION ON TUESDAY. SCATTERED
SNOW SHOWERS ARE POSSIBLE IN THE NORTHWEST FLOW, MAINLY OVER THE
I-80 CORRIDOR AND THE RIDGES. HIGH TEMPERATURES TUESDAY WILL BE
15 TO 20 DEGREES BELOW NORMAL.
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 /15Z SATURDAY THROUGH WEDNESDAY/
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TODAY WITH A
LINGERING STATIONARY BOUNDARY. AREAS NORTH OF THE WARM SECTOR
(BVI, FKL, DUJ, AND AT TIMES ZZV) HAVE SEEN CIGS DROP TO
IFR/LIFR. AREAS WITHIN THE WARM SECTOR (PIT, AGC, LBE, MGW, HLG)
CONTINUE TO BOUNCE BETWEEN VFR TO MVFR.
THIS AFTERNOON, WITH STRONG SOUTHWEST FLOW, CIGS NORTH OF PIT
ARE EXPECTED TO IMPROVE TO AT LEAST MVFR AND POTENTIALLY VFR.
HOWEVER, THE THREAT FOR THUNDERSTORMS INCREASES WITH AN UPTICK
IN INSTABILITY. PROBABILITIES FOR STRONG THUNDERSTORMS ARE
SLIGHTLY HIGHER SOUTH OF PIT.
A SHIFT IN THE FRONTAL BOUNDARY IS EXPECTED BETWEEN 23Z TO 01Z,
TO THE SOUTH. WITH THIS CHANGE, EXPECT WIDESPREAD IFR TO LIFR
CONDITIONS AS COLD AIR RESIDES AT THE SURFACE AND WARM AIR
CONTINUES TO ADVANCE ALOFT.
ADVANCING LOW-LEVEL DRY AIR WITH A COLD FRONT IS EXPECTED TO MIX
THE BOUNDARY LAYER LATE MORNING SUNDAY AND INCREASE CIGS FROM
NORTH TO SOUTH.
OUTLOOK...
HEAVY RAIN IS LIKELY TO BREAK SUNDAY INTO MONDAY AS AN UPPER-LEVEL
TROUGH IMPINGES UPON THE AREA, SWITCHING US OVER TO A COOLER PATTERN
FEATURING PERIODIC RAIN/SNOW CHANCES. THIS PATTERN SWITCH LIKELY
MEANS A CONTINUED PERIOD OF RESTRICTIONS THROUGH MID-WEEK.
HYDROLOGY
THE POTENTIAL FOR HEAVY RAINFALL CONTINUES THROUGH SUNDAY
EVENING. OVER THE LAST 2 DAYS, ONE TO TWO INCHES OF RAIN HAS
FALLEN. AN ADDITIONAL 0.75 TO 1.50 INCHES IS EXPECTED THROUGH
SUNDAY EVENING. LOCALIZED HIGHER AMOUNTS WITH THUNDERSTORMS
CAN'T BE RULED.
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.
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...22
NEAR TERM...22/CL
SHORT TERM...RACKLEY/22
LONG TERM...RACKLEY/22
AVIATION...HEFFERAN
HYDROLOGY...WM/HEFFERAN
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