612
FXUS61 KPBZ 051250
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
850 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 /12Z SATURDAY THROUGH WEDNESDAY/
SHOWERS AND EMBEDDED THUNDERSTORMS ACROSS THE REGION INTO THE EARLY
MORNING HOURS. MODELS ARE SHOWING A BRIEF BREAK IN THE RAIN BEFORE
ANOTHER LINE OF SHOWERS AND THUNDERSTORMS MOVES THROUGH DURING MID-
MORNING. THE BEST FORCING REMAINS CLOSER TO THE LOW AND A LOW-LEVEL
JET TO THE NORTH AND WEST OF PIT. THIS MAKES STORMS FAR LESS OF A
CERTAINTY FOR HLG AND MGW WHERE VCTS HAS BEEN INCLUDED IN THE TAFS.
AS CONVECTIVE ACTIVITY SURGES NORTH CIGS IN THE SOUTH ARE EXPECTED
TO RISE AND MANY MODELS SUPPORT VFR CONDITIONS ESTABLISHING
THEMSELVES IN THE WARM SECTOR BENEATH THE SURGING WARM FRONT. HOW
FAR THIS CLEARING GETS REMAINS A LARGER QUESTION WITH MODELS SHOWING
THE LINE NEAR/JUST SOUTH OF PIT/AGC.
BY THIS EVENING, MAJORITY OF THE AREA WILL RETURN TO MVFR
CONDITIONS. OVERNIGHT, AREAS NORTH OF PIT (BVI, FKL, AND DUJ) HAVE
THE HIGHEST PROBABILITY (50%-80%) OF REACHING IFR CONDITIONS.
OUTLOOK... THE UPPER OHIO RIVER VALLEY REMAINS POSITIONED BETWEEN A
MOUNTAIN WEST TROUGH AND EAST COAST RIDGE THAT WILL FOSTER MULTIPLE
ROUNDS OF MODERATE TO LOCALLY HEAVY RAIN AND THUNDERSTORMS THROUGH
SUNDAY MORNING. TIMING AND SHAPE OF EACH PASSING SHORTWAVE TROUGH
REMAINS VARIABLE, WHICH WILL ALTER THE AXIS OF HEAVIEST
PRECIPITATION AND LOWEST CLOUDS. CONTINUED LIMITED WINDOWS OF VFR
AND DRY CONDITIONS ARE EXPECTED THROUGH THE PERIOD AS THE PATTERN
CONTINUES TO FAVOR BOUTS OF MVFR/IFR RESTRICTIONS IN ANY HEAVIER
RAIN SHOWERS AND OCCASIONAL THUNDERSTORMS.
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. AT
THIS TIME, AREAS ACROSS OHIO HAVE THE POTENTIAL TO SEE THE
HEAVIEST RAINFALL, WHERE A FLOOD WATCH CONTINUES. CURRENT NBM
VALUES INDICATE A 40 TO 60 PERCENT CHANCE OF 2 INCHES OF RAIN
OVER A 72 HR PERIOD IN THIS REGION. THE EXACT LOCATION OF THE
HEAVIEST RAIN WILL DEPEND ON THE POSITION OF A QUASI-STATIONARY
SURFACE FRONT AND HOW MUCH CONVECTION DEVELOPS TODAY AND SUNDAY.
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...LUPO/AK
HYDROLOGY...
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