160
FXUS61 KPBZ 190722
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
322 AM EDT SAT APR 19 2025
SYNOPSIS
SHOWERS AND THUNDERSTORMS RETURN TODAY WITH A SLOW MOVING COLD
FRONT. A FEW STORMS COULD BE SEVERE. GENERALLY DRY WEATHER
RETURNS SUNDAY AS THE FRONT MOVES SOUTH, AND HIGH PRESSURE
BRIEFLY BUILDS IN. THE FRONT RETURNS NORTH SUNDAY NIGHT WITH
SHOWER AND THUNDERSTORM CHANCES RETURNING. A COLD FRONT WILL
MAINTAIN SHOWERS AND THUNDERSTORMS ACROSS THE REGION MONDAY.
NEAR TERM /THROUGH TODAY/
KEY MESSAGES:
- SHOWERS AND THUNDERSTORMS RETURN
- MARGINAL RISK (LEVEL 1 OUT OF 5) FOR SEVERE STORMS
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SURFACE LOW PRESSURE WAS CENTERED ACROSS SOUTHERN ONTARIO, WITH
A COLD FRONT TRAILING SOUTHWEST THROUGH MICHIGAN AND ILLINOIS.
AHEAD OF THE FRONT, A VORTICITY MAXIMUM ACROSS NW OH ALONG THE
EDGE OF A STRONG LOW LEVEL JET WAS RESULTING IN SHOWER AND
THUNDERSTORM DEVELOPMENT. THIS VORT MAX IS EXPECTED TO TRACK
ACROSS PORTIONS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES
REGION THIS MORNING. MOST OF THE SHOWERS/STORM ACTIVITY SHOULD
BE NORTH OF PITTSBURGH WITH THIS INITIAL ROUND. MOST OF THE
INSTABILITY WAS ELEVATED, SEEN ON THE LATEST MESOANALYSIS IN
MUCAPE AND SHOWALTER FIELDS.
THE SURFACE COLD FRONT IS PROGGED TO APPROACH THE UPPER OHIO
VALLEY REGION LATER TODAY AS IT TRACKS SOUTHEASTWARD. ADDITIONAL
SHOWER AND THUNDERSTORM DEVELOPMENT IS EXPECTED ALONG AND AHEAD
OF THE FRONT. ASCENT SHOULD BE ENHANCED BY A MID LEVEL JET.
CONVECTION COULD BE INITIALLY SOMEWHAT LIMITED BY WARM AIR IN
THE MID LEVELS, THOUGH FORCING ALONG AND AHEAD OF THE FRONT
SHOULD ERODE THIS WARM AIR.
STRONG SHEAR WILL BE IN PLACE, ENHANCED BY THE MID LEVEL JET. MU
CAPE IS PROGGED AT 500-1000 J/KG. WITH THIS EXPECTED SHEAR AND
INSTABILITY, THERE IS A POTENTIAL FOR A FEW STRONG TO SEVERE
STORMS DURING THE AFTERNOON AND EARLY EVENING HOURS. THE STORM
PREDICTION CENTER HAS MOST OF OUR AREA IN A MARGINAL RISK FOR
SEVERE STORMS. AREAS SOUTH OF THE WV/PA BORDER WILL LIKELY SEE
INSTABILITY WANE AS THE SURFACE FRONT APPROACHES THIS EVENING,
WITH LESSER CHANCES FOR STRONG STORMS.
THE MAIN HAZARD ASSOCIATED WITH SEVERE STORMS WILL BE DAMAGING
WIND, WITH STRONG SHEAR AND SOME MID LEVEL DRY AIR. HAIL WILL
ALSO BE POSSIBLE WITH THE STRONG SHEAR IN PLACE.
TEMPERATURES WILL BE WARM AGAIN TODAY, WITH READINGS 10 TO 15
DEGREES ABOVE AVERAGE.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/
KEY MESSAGES:
- SEVERE WEATHER POTENTIAL QUICKLY WANES EARLY THIS EVENING
- DRY SUNDAY
- MORE SHOWERS/STORMS SUNDAY NIGHT AND MONDAY
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THE SEVERE WEATHER POTENTIAL SHOULD QUICKLY WANE THIS EVENING
WITH DIMINISHING INSTABILITY. THE SOUTHEASTWARD PROGRESSION OF
THE FRONT SHOULD ACCELERATE TONIGHT AS THE FLOW ALOFT BECOMES
MORE PERPENDICULAR TO THE FRONT AS IT SHIFTS TO THE WNW. SHOWER
AND THUNDERSTORM SHOULD GRADUALLY END AFTER FROPA.
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 /07Z SATURDAY THROUGH WEDNESDAY/
VFR CONDITIONS ARE FORECAST TO CONTINUE THROUGH MUCH OF THE
OVERNIGHT PERIOD. AFTER A BRIEF LULL THE PAST COUPLE HOURS, GUSTY
SOUTHWEST WINDS ARE MOVING BACK INTO THE AREA FROM WEST TO EAST
AS WELL AS AN OVERSPREADING LOW-LEVEL JET OF 40 TO 50 KNOTS,
CREATING SOME LOW-LEVEL WIND SHEAR CONCERNS AT MOST TAF SITES
THROUGH THE REMAINDER OF THE NIGHT.
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 11Z,
WITH FKL AND DUJ HAVING THE BEST CHANCE OF SEEING RAIN BETWEEN
THEN AND ~16Z. AS THE COLD FRONT SETTLES TOWARDS THE REGION, AN
INCREASE IN SHOWER AND THUNDERSTORM COVERAGE IS ANTICIPATED.
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 ARE EXPECTED
SATURDAY AFTERNOON AND NIGHT AS A COLD FRONT TRACKS SLOWLY SE
ACROSS THE UPPER OHIO VALLEY REGION. VFR SHOULD RETURN SUNDAY AS
THE FRONT DROPS SOUTH OF THE AREA.
SHOWERS AND RESTRICTIONS ARE POSSIBLE SUNDAY NIGHT AS THE FRONT
MOVES BACK NORTH AS A WARM FRONT.
SHOWERS ARE LIKELY (WITH POSSIBLE THUNDERSTORMS) ON MONDAY WITH
A CROSSING COLD FRONT. VFR RETURNS TUESDAY UNDER HIGH PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...WM
NEAR TERM...WM
SHORT TERM...WM
LONG TERM...WM
AVIATION...CERMAK/CL/SHALLENBERGER
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