630
FXUS61 KPBZ 201359
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
959 AM EDT SUN APR 20 2025
SYNOPSIS
DRY WEATHER IS EXPECTED TODAY UNDER HIGH PRESSURE. SCATTERED
SHOWERS AND THUNDERSTORMS WILL RETURN AFTER MIDNIGHT WITH A WARM
FRONT. SHOWERS AND POSSIBLE GUSTY THUNDERSTORMS ARE EXPECTED
WITH A COLD FRONT MONDAY AFTERNOON.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- DRY AND COOLER TODAY
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INCREASE SUBSIDENCE IN THE WAKE OF THE COLD FRONT HAS CLEARED A
MAJORITY OF MID AND LOW-LEVEL CLOUDS ACROSS THE REGION.
TEMPERATURES WILL STILL TREND ABOVE-AVERAGE THIS AFTERNOON
DESPITE NORTHERLY FLOW AT THE SURFACE. HOWEVER, HIGH
TEMPERATURES WILL BE 15 TO 20 DEGREES COOLER THAN ON SATURDAY.
SURFACE WINDS WILL GRADUALLY SHIFT FROM NORTH TO SOUTHEAST
THROUGHOUT THE DAY AS A NEW LOW PRESSURE TRACKS INTO THE OHIO
RIVER VALLEY. MID AND UPPER-LEVEL CLOUDS WILL INCREASE FROM
SOUTH TO NORTH THIS AFTERNOON/EVENING, AHEAD OF AN EXPECTED
WARM FRONT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
KEY MESSAGES:
- WARM FRONT RETURNS SCATTERED SHOWERS/STORMS TONIGHT
- SHOWERS AND GUSTY THUNDERSTORMS MONDAY WITH A COLD FRONT
- DRY TUESDAY AND TUESDAY NIGHT
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THE RIDGE WILL MOVE EAST THIS EVENING, AS A TROUGH OVER THE
UPPER MIDWEST MOVES EAST. THE RESULTING SW FLOW ALOFT AHEAD OF
THE TROUGH WILL BRING A WARM FRONT BACK NORTH TONIGHT. SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH INCREASING MOISTURE
AND ASCENT IN SW FLOW ALOFT, AND WITH ELEVATED INSTABILITY
(SHOWALTER INDEX AROUND -1.) THE SCATTERED SHOWERS/STORMS
SHOULD END MONDAY MORNING AS THE FRONT LIFTS TO THE NORTH.
THE TROUGH AND ASSOCIATED SURFACE COLD FRONT ARE PROGGED TO
ADVANCE EASTWARD ON MONDAY. A BAND OF SHOWERS AND THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT, WITH
INCREASING MOISTURE AND VORTICITY ADVECTION. A PREFRONTAL TROUGH
COULD ALSO RESULT IN ADDITIONAL SHOWERS/STORMS AHEAD OF THE MAIN
FRONT. A JET ALOFT WILL ALSO ENHANCE ASCENT, AS WELL AS SHEAR.
CAPE WILL ALSO INCREASE AHEAD OF THE FRONT, WITH CURRENT HREF
PROGS BETWEEN 500 AND 1000 J/KG. THE AMOUNT OF DESTABILIZATION
THAT OCCURS WILL DEPEND ON THE TIMING OF THE FRONT, AND THE
EFFECTS A PREFRONTAL TROUGH WILL HAVE ON THE ATMOSPHERE, THOUGH
AT THIS TIME IT APPEARS THERE IS AT LEAST SOME POTENTIAL FOR
GUSTY WIND IN STORMS THAT DEVELOP MONDAY MAINLY IN THE
AFTERNOON.
SHOWER AND THUNDERSTORM CHANCES WILL END FROM W-E MONDAY
EVENING AS FROPA OCCURS. DRY WEATHER WILL THEN CONTINUE TUESDAY
AND TUESDAY NIGHT AS SURFACE HIGH PRESSURE BUILDS ACROSS THE
UPPER OHIO VALLEY REGION, UNDER ZONAL FLOW ALOFT. TEMPERATURES
ARE EXPECTED TO AVERAGE ABOVE SEASONABLE LEVELS THROUGH THE
PERIOD.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
KEY MESSAGES:
- SEASONABLY WARM WEATHER CONTINUES
- PRECIPITATION CHANCES DEPENDENT ON SHORTWAVE MOVEMENT AND
RIDGE LOCATION
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MODEL ENSEMBLES INDICATE A NEARLY ZONAL FLOW ALOFT WILL CONTINUE
THROUGH MID WEEK, AS SURFACE HIGH PRESSURE SLIDES EAST ACROSS
THE UPPER OHIO VALLEY REGION. THIS SHOULD MAINTAIN DRY AND
WARMER THAN AVERAGE WEATHER THROUGH EARLY THURSDAY. THE UPPER
AIR PATTERN IS PROGGED TO BEGIN TO AMPLIFY BY LATE WEEK, AS A
TROUGH DEVELOPS ACROSS THE PLAINS. A LEAD SHORTWAVE IN SW FLOW
ALOFT AHEAD OF THE APPROACHING TROUGH SHOULD RESULT IN
INCREASING SHOWERS CHANCES LATER THURSDAY INTO FRIDAY AS IT
CROSSES THE UPPER OHIO VALLEY REGION.
THE MAIN TROUGH, AND AN ASSOCIATED SURFACE COLD FRONT, IS
EXPECTED TO APPROACH AND CROSS THE REGION FRIDAY AND FRIDAY
NIGHT, WITH SHOWERS LIKELY. THE RAIN COULD LINGER INTO SATURDAY,
DEPENDING ON THE SPEED OF THE TROUGH AND SURFACE FRONT.
TEMPERATURES SHOULD CONTINUE TO AVERAGE ABOVE SEASONABLE LEVELS
THROUGH THE PERIOD.
AVIATION /14Z SUNDAY THROUGH THURSDAY/
INCREASE SUBSIDENCE IN THE WAKE OF A COLD FRONT HAS CLEARED A
MAJORITY OF MID AND LOW-LEVEL CLOUDS ACROSS THE REGION. MVFR
RETURNING TO WIDESPREAD VFR.
WINDS ARE EXPECTED TO SHIFT FROM NORTH TO SOUTHEAST THROUGHOUT
THE DAY, AHEAD OF A WARM FRONT.
A PASSING WARM FRONT EARLY MONDAY MAY CREATE ISOLATED
RESTRICTIONS AND THUNDERSTORMS BETWEEN 06Z TO 10Z. LIGHTNING AND
SMALL HAIL COULD BE IN THE VICINITY OF FKL/DUJ/BVI DURING THIS
TIME PERIOD.
THERE WILL BE A BRIEFING BREAK IN SHOWER AND THUNDERSTORMS
CHANCES AHEAD OF A COLD FRONT BETWEEN 10Z TO 17Z. PROBABILITY
OF LIGHTNING AND STRONG WINDS ASSOCIATED WITH THUNDERSTORMS
INCREASES AFTER 17Z WITH A PRE-FRONTAL TROUGH FOLLOWED BY THE
COLD FRONT.
OUTLOOK...
VFR AND MOSTLY DRY WEATHER RETURN TUESDAY AND WEDNESDAY,
FOLLOWED BY ANOTHER WEATHER SYSTEM BRINGING INCREASING CHANCES
FOR RAIN AND RESTRICTIONS LATE THIS WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...HEFFERAN
NEAR TERM...HEFFERAN
SHORT TERM...WM
LONG TERM...WM
AVIATION...HEFFERAN
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