783
FXUS61 KPBZ 011954 CCA
AFDPBZ
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE PITTSBURGH PA
354 PM EDT TUE APR 1 2025
SYNOPSIS
DRY WEATHER WILL CONTINUE TONIGHT UNDER HIGH PRESSURE. SHOWERS
AND THUNDERSTORMS RETURN WEDNESDAY INTO THE WEEKEND AS A FRONT
STALLS ACROSS THE REGION. LOCALLY HEAVY RAINFALL AND STRONG
STORMS ARE POSSIBLE.
NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/
KEY MESSAGES:
- DRY UNDER HIGH PRESSURE
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DRY WEATHER WILL CONTINUE TONIGHT AS HIGH PRESSURE MOVES EAST
ACROSS THE REGION. MID AND HIGH LEVEL CLOUDS WILL INCREASE IN
WARM ADVECTION AHEAD OF THE NEXT APPROACHING SHORTWAVE TROUGH.
LOW TEMPERATURES ARE EXPECTED TO BE NEAR SEASONABLE LEVELS,
THOUGH READINGS SHOULD INCREASE LATE TONIGHT IN THE WARM
ADVECTION.
SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/
KEY MESSAGES:
- SHOWERS AND THUNDERSTORMS RETURN WEDNESDAY WITH A WARM FRONT
- WAVES OF SHOWERS AND THUNDERSTORMS CONTINUE WEDNESDAY NIGHT
THROUGH FRIDAY
- FLOOD WATCH FOR PORTIONS OF OHIO
- LOCALLY HEAVY RAINFALL POSSIBLE
- SEVERE STORMS POSSIBLE WEDNESDAY AND THURSDAY
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STRONG SURFACE LOW PRESSURE IS EXPECTED TO TRACK ACROSS THE
PLAINS AND UPPER MIDWEST REGION ON WEDNESDAY, AS A WARM FRONT
EXTENDING EAST OF THE LOW LIFTS ACROSS THE UPPER OHIO VALLEY
REGION. A VORTICITY MAXIMUM IN SW FLOW ALOFT WILL CROSS THE
REGION AT THE SAME TIME, SUPPORTING A WAVE OF SHOWERS AND
THUNDERSTORMS ACROSS THE AREA. INSTABILITY WILL BE ELEVATED,
WITH A STRONG INVERSION PROGGED ABOVE THE SURFACE. WITH STRONG
SHEAR ALSO IN PLACE, THE POTENTIAL EXISTS FOR HAIL IN ANY STORMS
DURING THE DAY WEDNESDAY. MUCAPE VALUES ARE PROGGED AT AROUND
500 J/KG AS THE SHORTWAVE CROSSES. THE STORM POTENTIAL SHOULD
END LATER IN THE AFTERNOON AS THE INITIAL WAVE EXITS. IN
ADDITION, DOWNSLOPING SE WIND SHOULD RESULT IN WIND GUSTS FROM
30-40MPH JUST WEST OF THE LAUREL HIGHLAND RIDGES WEDNESDAY. WIND
DIRECTION AND INVERSION HEIGHTS CURRENTLY LOOK LESS THAN OPTIMAL
FOR HIGHER GUSTS.
MAINLY DRY WEATHER IS EXPECTED THE FIRST PART OF WEDNESDAY NIGHT
WITH SUBSIDENCE BEHIND THE INITIAL WAVE. SHOWERS AND
THUNDERSTORMS WILL INCREASE OVERNIGHT AS A COLD FRONT AND
SHORTWAVE TROUGH APPROACH. SIGNIFICANT SHEAR IS PROGGED TO BE IN
PLACE AS THE FRONT APPROACHES, WITH ELEVATED INSTABILITY. THE
POTENTIAL FOR SEVERE STORMS WILL INCREASE LATE AS THE FRONT
APPROACHES, THOUGH THE AVAILABLE INSTABILITY COULD BE A LIMITING
FACTOR.
THE FORWARD PROGRESS OF THE FRONT IS EXPECTED TO SLOW ON
THURSDAY AS THE FRONT BECOMES PARALLEL TO THE FLOW ALOFT.
UNCERTAINTY IN THE EXACT POSITION OF THE FRONT EXISTS, WHICH
WILL IMPACT AREAS WHERE HEAVY RAIN FALLS, AND WHICH AREAS HAVE
THE POTENTIAL FOR SEVERE STORMS. THE STRONGEST UPPER SUPPORT FOR
ASCENT EXITS THE REGION LATER THURSDAY NIGHT INTO FRIDAY, WITH A
TEMPORARY DECREASE IN THE HEAVY RAIN/STORM POTENTIAL. THE FRONT
IS ALSO PROGGED TO DRIFT JUST SOUTH OF THE REGION DURING THE
DAY, RESULTING IN DECREASING POPS.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
KEY MESSAGES:
- SHOWERS/THUNDERSTORMS INCREASE FRIDAY NIGHT AND SATURDAY
- POTENTIAL FOR HEAVY RAINFALL
- COLDER NEXT WEEK
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A SURFACE LOW IS EXPECTED TO TRACK NE OUT OF THE MISSISSIPPI
VALLEY REGION FRIDAY NIGHT, RETURNING THE FRONT NORTHWARD.
SHOWERS AND THUNDERSTORMS WILL AGAIN INCREASE IN COVERAGE AS THE
FRONT AND SURFACE LOW MOVE ACROSS THE UPPER OHIO VALLEY REGION
THROUGH SATURDAY. THE SEVERE WEATHER POTENTIAL IS EXPECTED TO BE
LIMITED WITH THE AMOUNT OF INSTABILITY IN PLACE, THOUGH THE
LOCALLY HEAVY RAIN POTENTIAL WILL INCREASE.
THE LOW IS EXPECTED TO MOVE NE OF THE AREA ON SUNDAY, PULLING A
COLD FRONT ACROSS THE REGION. THE PASSAGE OF THE FRONT WILL
BRING THE HEAVY RAIN AND STORM POTENTIAL TO AN END LATER IN THE
DAY. AN UPPER TROUGH IS THEN EXPECTED TO PERSIST ACROSS THE NE
CONUS EARLY IN THE WEEK, RESULTING IN COOLER TEMPERATURES AND
RAIN/SNOW SHOWER CHANCES.
AVIATION /20Z TUESDAY THROUGH SUNDAY/
WANING COLD ADVECTION AND DRIER AIR WORKING IN WITH BUILDING
HIGH PRESSURE HAS ERODED THE LOW STRATUS DECK ALBEIT QUITE
SLOWLY AS MOISTURE REMAINED STUBBORN UNDER A STRONG INVERSION
AROUND 850 MB. SOME SCATTERED LOW-LEVEL COVERAGE WILL LINGER
THROUGH THE AFTERNOON, BUT INCREASING CIRRUS THIS EVENING WILL
BECOME THE STORY OVERNIGHT AS IT THICKENS AND LOWERS WITH
INCREASING UPPER LEVEL MOISTURE AHEAD OF OUR NEXT SYSTEM ON
WEDNESDAY.
THE MORNING HOURS WEDNESDAY WILL BE DRY, BUT LATEST GUIDANCE IS
EXTENDING A SHIELD OF SHOWERS AND STORMS AS FAR SOUTH AS MGW IN
THE EARLY AFTERNOON HOURS. CONFIDENCE IS NOT HIGH ON THE
SOUTHERN EXTENT OF IT, BUT TRENDS HAVE BEEN TOWARD A SOUTHWARD
SHIFT. INTRODUCED A PROB30 GROUP AT ZZV AND PIT, BUT IT WILL BE
JUST OUTSIDE THE CURRENT TAF PERIOD AT ALL OTHER SITES.
SOUNDINGS SUGGEST AN ELEVATED NATURE TO THE CONVECTION, SO NOT
EXPECTING MIXING DOWN OF STRONGER WIND GUSTS WITH IT AT THIS
TIME, THOUGH WITH AN INCREASING LOW-LEVEL JET, A PERIOD OF LLWS
IS POSSIBLE IN THE AFTERNOON HOURS. SOME IMPROVEMENT IS
POSSIBLE IN THE EVENING HOURS AHEAD OF A COLD FRONT THAT WILL
BRING ANOTHER ROUND OF SHOWERS AND STORMS OVERNIGHT WEDNESDAY
NIGHT.
WIND OUT OF THE NORTH THIS AFTERNOON WILL GRADUALLY VEER
THROUGH THE TAF PERIOD BECOMING NORTHEASTERLY TONIGHT AND
ULTIMATELY EASTERLY EARLY WEDNESDAY MORNING. DESPITE SHALLOW
DECOUPLING OVERNIGHT ON FORECAST SOUNDINGS, A TIGHTENING
PRESSURE GRADIENT WILL KEEP A LIGHT FLOW PREVAILING.
OUTLOOK...
RESTRICTIONS WILL CONTINUE EARLY THURSDAY AND THROUGH THE
WEEKEND WITH THE COLD FRONT PASSAGE AND ADDITIONAL ROUNDS OF
RAIN MOVING THROUGH THE AREA OVER THE NEXT SEVERAL DAYS.
HYDROLOGY
THE POTENTIAL FOR HEAVY RAINFALL WILL EXIST BEGINNING WEDNESDAY
NIGHT, AND CONTINUING INTO SUNDAY. AT THIS TIME, AREAS ACROSS
OHIO HAVE THE POTENTIAL TO SEE THE HEAVIEST RAINFALL, WHERE A
FLOOD WATCH HAS BEEN ISSUED. CURRENT NBM VALUES INDICATE A 60
PERCENT CHANCE OR GREATER OF AT LEAST 2 INCHES OF RAIN OVER A 72
HR PERIOD IN THIS REGION, WITH LESSER PROBABILITIES FURTHER EAST.
THE EXACT LOCATION OF HEAVY 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...NONE.
OH...FLOOD WATCH FROM WEDNESDAY EVENING THROUGH SUNDAY MORNING FOR
OHZ039-040-048-049-057>059-068-069.
WV...NONE.
SYNOPSIS...WM
NEAR TERM...WM
SHORT TERM...WM
LONG TERM...WM
AVIATION...MLB
HYDROLOGY...WM
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