630
FXUS61 KPBZ 191220
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
820 AM EDT SAT APR 19 2025
SYNOPSIS
SHOWERS AND THUNDERSTORMS RETURN TODAY WITH A SLOW MOVING COLD
FRONT. A FEW STORMS COULD BE STRONG TO SEVERE EARLY TO LATE
AFTERNOON. GENERALLY DRY WEATHER RETURNS SUNDAY AS THE FRONT
MOVES SOUTH, AND HIGH PRESSURE BRIEFLY BUILDS IN.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- SHOWERS AND THUNDERSTORMS RETURN LATE MORNING
- MARGINAL RISK (LEVEL 1 OUT OF 5) FOR SEVERE STORMS THIS
AFTERNOON
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8:15AM UPDATE:
A MESOSCALE CONVECTION SYSTEM (MCS) IS CURRENTLY
TRACKING THROUGH NORTH CENTRAL OHIO THIS MORNING. WITH AN
ENHANCED LOW CAPE/HIGH SHEAR ENVIRONMENT, A FEW STORMS HAVE BEEN
CONSIDERED SEVERE (+50MPH WIND GUSTS REPORTED IN ISOLATED
AREAS). THE MCS WILL LIKELY TRACK NORTH OF I-80 AND COULD BE
INFLUENCED BY DRY AIR OVER WESTERN OHIO, DISSOLVING RAPID GROWTH
IN UPDRAFTS. LIGHTNING MAY BE THE ONLY IMPACTS ALONG WITH SUB-
SEVERE WIND GUSTS WITH WEAKER DOWNDRAFTS.
EARLY MORNING TEMPERATURES ARE CONSIDERED 30 DEGREES ABOVE
AVERAGE, LINGERING IN THE UPPER-60S AND MID-70S DUE TO STRONG
WARM ADVECTION ASSOCIATED WITH AN ELONGATED RIDGE OVER THE EAST
COAST. WITH A CLOSED 500MB LOW SLOWLY ADVANCING EAST OF
CALIFORNIA THIS MORNING, A STALLED COLD FRONT IS SITUATED TO OUR
WEST. THE FRONTAL BOUNDARY IS CURRENTLY SITUATED NEAR DETROIT
AND STRETCHES SOUTHWEST INTO CENTRAL OKLAHOMA. IN THE VICINITY
OF THE FRONT, SHOWERS AND THUNDERSTORMS ARE CURRENTLY ONGOING.
AFTER 11AM, AS THE RIDGE SLOWLY BREAKS DOWN AND MID TO UPPER-LVL
WINDS SHIFT FROM THE WEST, DEW POINTS WILL LIKELY INCREASE AND
INCREASE OUR CHANCES OF INSTABILITY. WITH EFFECTIVE WIND SHEAR
ABOVE 30KTS IN PLACE, OUR PROBABILITY OF STRONG TO SEVERE
STORMS INCREASES EARLY THIS AFTERNOON AND CONTINUES OT LATE
EVENING. IF CONDITIONS PERMIT, SEVERE STORMS COULD CREATE
DAMAGING WIND AND QUARTER SIZED HAIL. DESPITE STRONG WIND SHEAR
ALOFT, CEILINGS MAY BE CONSIDERED TOO HIGH FOR A TORNADO THREAT
TO PROMOTE STRETCHING WITH ROTATING UPDRAFTS.
THE PROBABILITY OF A FAVORABLE SEVERE STORM ENVIRONMENT WILL
LIKELY DECREASE FROM NORTH TO SOUTH BETWEEN 7PM TO 9PM WITH THE
LOSS OF DIURNAL HEATING AND THE PASSAGE OF A COLD FRONT.
DEPENDING ON THE POSITION OF THE COLD FRONT BY MIDNIGHT, THERE
IS ALSO THE CHANCE TO OBSERVING RECORD BREAKING HIMIN
TEMPERATURES AT CLIMATE SITES SOUTH OF PIT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
KEY MESSAGES:
- DRY SUNDAY
- MORE SHOWERS/STORMS SUNDAY NIGHT AND MONDAY
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DRY WEATHER IS EXPECTED ON SUNDAY AS THE FRONT MOVES SOUTH OF
THE REGION, AND RIDGING BUILDS IN. THE UPPER LEVEL FLOW WILL
BECOME SW AGAIN ON THE WESTERN SIDE OF THE RIDGE SUNDAY NIGHT,
DRIVING THE FRONT BACK NORTH AS A WARM FRONT. ADDITIONAL SHOWER
CHANCES ARE EXPECTED AS THE FRONT LIFTS NORTH. ENOUGH ELEVATED
INSTABILITY IS ALSO PROGGED FOR THE POTENTIAL FOR A FEW
THUNDERSTORMS.
THE AREA WILL BE IN THE WARM SECTOR AGAIN ON MONDAY, AHEAD OF AN
APPROACHING SHORTWAVE TROUGH AND SURFACE COLD FRONT. SHOWERS AND
POSSIBLE THUNDERSTORMS ARE EXPECTED MONDAY AFTERNOON AS THE
FRONT CROSSES. STRONG SHEAR IS EXPECTED TO BE IN PLACE, THOUGH
CURRENT MODEL PROGGED INSTABILITY IS MINIMAL. WILL MONITOR LATER
TRENDS. SHOWERS AND STORMS SHOULD END FROM W-E MONDAY AFTER
FROPA.
LONG TERM /TUESDAY THROUGH FRIDAY/
KEY MESSAGES:
- DRY THROUGH MID WEEK
- SHOWER CHANCES RETURN LATE WEEK
- WARMER THAN AVERAGE TEMPERATURES THROUGH MUCH OF THE PERIOD
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MODEL ENSEMBLES INDICATE ZONAL FLOW ALOFT WILL PERSIST ACROSS
THE CONUS THROUGH MIDWEEK, AS SURFACE HIGH PRESSURE MOVES ACROSS
THE UPPER OHIO VALLEY REGION. THIS SHOULD RESULT IN MAINLY DRY
AND WARM WEATHER THROUGH AT LEAST WEDNESDAY. A WEAK TROUGH
EMBEDDED IN THE FLOW COULD RESULT IN MINIMAL SHOWER CHANCES ON
THURSDAY AS IT CROSSES THE REGION, THOUGH MAINTAINED POPS AT
SLIGHT CHANCE FOR NOW.
A DEVELOPING CENTRAL CONUS TROUGH IS PROGGED TO DEVELOP BY LATE
WEEK. MOISTURE IN SW FLOW ALOFT, AND AN APPROACHING ASSOCIATED
SURFACE LOW, SHOULD RESULT IN AN INCREASE IN SHOWER CHANCES
AGAIN BY FRIDAY. TEMPERATURES ARE EXPECTED TO AVERAGE ABOVE
SEASONABLE LEVELS THROUGH THE PERIOD.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
CLOUD DECKS ARE LOWERING TO THE 5-8KFT RANGE THROUGH THE
MORNING AHEAD OF AN APPROACHING COLD FRONT. SHOWERS AND POSSIBLY
A FEW RUMBLES OF THUNDER COULD THEN ENTER THE REGION AFTER 14Z,
WITH FKL AND DUJ HAVING THE BEST CHANCE OF SEEING RAIN FIRST.
AS THE COLD FRONT SETTLES TOWARDS THE REGION, AN INCREASE IN
SHOWER AND THUNDERSTORM COVERAGE IS ANTICIPATED BETWEEN 18Z TO
23Z. GIVEN THE UNCERTAINTY SURROUNDING SUB-CLOUD EVAPORATION
(AT LEAST INITIALLY) AND THE ANTICIPATED SPORADIC/CLUSTERED
NATURE OF THUNDERSTORMS, HAVE MAINTAINED PROB30 TO ACCOUNT FOR
THUNDERSTORM POTENTIAL WHILE ATTEMPTING TO HIGHLIGHT THE BEST
OVERALL WINDOWS FOR RAIN USING PREVAILING -SHRA. THERE IS LOW-
END POTENTIAL FOR SOME STORMS TO BECOME STRONG OR SEVERE,
PRIMARILY DURING THE AFTERNOON AND EVENING. SOME OF THE MORE
SOUTHERN TERMINALS LIKE MGW MIGHT ESCAPE WITHOUT ANY PRECIP.
RESTRICTIONS ACCOMPANY SHOWERS AND STORMS ALONG THE FRONT ITSELF
BEFORE IMPROVING BEHIND THE COLD FRONT OVERNIGHT INTO SUNDAY
MORNING.
OUTLOOK...
SHOWERS, RESTRICTIONS, AND POSSIBLE THUNDERSTORMS COULD CONTINUE
SOUTH OF BVI PASSED 00Z SUNDAY WITH SLOW ADVANCEMENT OF THE
COLD FRONT.
VFR SHOULD RETURN SUNDAY AS THE FRONT DROPS SOUTH OF THE AREA.
A PASSING WARM FRONT EARLY MONDAY MAY CREATE ISOLATED
RESTRICTIONS AND THUNDERSTORMS.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...HEFFERAN
NEAR TERM...WM
SHORT TERM...WM
LONG TERM...WM
AVIATION...CERMAK/HEFFERAN
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