079
FXUS61 KPBZ 290450
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1250 AM EDT THU MAY 29 2025
SYNOPSIS
LIGHT RAIN AND DRIZZLE WILL TAPER OFF THIS EVENING WITH LOW
CHANCES OVERNIGHT. ISOLATED THUNDERSTORMS ARE POSSIBLE THURSDAY,
BEFORE MORE WIDESPREAD RAINFALL RETURNS FRIDAY INTO SATURDAY.
DRIER AND WARMER WEATHER LOOKS TO RETURN SUNDAY INTO THE MIDDLE
OF NEXT WEEK.
NEAR TERM /UNTIL 6 AM THIS MORNING/
KEY MESSAGES:
- RAIN AND DRIZZLE DISSIPATING THIS EVENING.
- MAINLY DRY OVERNIGHT WITH FOGGY CONDITIONS.
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EVENING UPDATE: AS EXPECTED, PRECIPITATION COVERAGE HAS BECOME
MORE SCATTERED THIS EVENING WITH MORE FOCUSED PRECIPITATION
MOVING EASTWARD. LOOKING AT ACARS SOUNDINGS TOO OUR WEST, MID-
LEVEL DRY AIR HAS REACHED CVG AND IS HEADING TOWARDS CMH
LOWERING PRECIPITATION CHANCES ACROSS OH THIS EVENING.
SEVERAL SITES ACROSS CENTRAL OH HAVE ALREADY BEGUN TO SEE FOG
FORMATION WITH LIGHT WINDS AND AMPLE LOW-LEVEL MOISTURE OVER
WET GROUND. FOG/MIST/SPRINKLES CAN CONTINUE ACROSS THE REGION
TONIGHT.
FEW CHANGES MADE TO THE PREVIOUS FORECAST PACKAGE. KEPT THUNDER
CHANCES OUT OF THE FORECAST THIS EVENING AND OVERNIGHT WITH
LACKING INSTABILITY. POPS ACROSS OH WERE TRIMMED THIS EVENING
SOME GIVEN CURRENT RADAR TRENDS AND NOTED MID-LEVEL DRY AIR. A
PORTION OF THE PREVIOUS DISCUSSION BELOW:
GENERALLY DRY WEATHER IS EXPECTED OVERNIGHT AS THE UPPER TROUGH
AXIS LIFT NORTHWARD AND OCCLUDED FRONT PASSES. HOWEVER, A FEW
ISOLATED SHOWERS/SPRINKLES MAY OCCUR AS A WEAK SHORTWAVE
CROSSES. WITH RESIDUAL LOW-LEVEL MOISTURE, LIGHT WINDS, AND
WARM ADVECTION, THERE IS A POTENTIAL FOR DENSE FOG AFTER
MIDNIGHT. THIS WILL ALSO KEEP OVERNIGHT LOW TEMPERATURES A
COUPLE DEGREES ABOVE AVERAGE.
SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/
KEY MESSAGES:
- BRIEFLY WARMER THURSDAY WITH ISOLATED SHOWERS/THUNDERSTORMS
POSSIBLE.
- WIDESPREAD RAINFALL RETURNS FRIDAY INTO SATURDAY WITH LOW
PRESSURE.
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SURFACE LOW PRESSURE CONTINUES LIFTING NORTH INTO ONTARIO/QUEBEC
ON THURSDAY WHILE WEAK SURFACE HIGH PRESSURE AND QUASI-
ZONAL/SOUTHWEST FLOW ALOFT BUILDS OVER OUR AREA. THIS WILL
SUPPORT GENERALLY DRY WEATHER AND SEASONABLE TEMPERATURES.
HOWEVER, GIVEN LITTLE CHANGE IN BOUNDARY LAYER MOISTURE FROM
TODAY, A FEW ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE. CAPPED AREA POPS AROUND 25%. ANY LINGERING SHOWERS
SHOULD DIMINISH WITH SUNSET.
UPPER LOW PRESSURE CURRENTLY OVER THE UPPER MIDWEST WILL BEGIN
TO PHASE WITH THE NORTHERN STREAM INTO FRIDAY, EVENTUALLY
CROSSING THE AREA ON SATURDAY AS A NUMBER OF SHORTWAVES RIPPLE
THROUGH THE FLOW. THIS WILL PROMOTE SURFACE CYCLOGENESIS AS LOW
PRESSURE MOVES JUST SOUTH OF THE AREA ON FRIDAY AND DEEPENS OVER
THE MID-ATLANTIC SATURDAY. CONFIDENCE HAS INCREASED IN
WIDESPREAD RAINFALL ASSOCIATED WITH THIS LOW BEGINNING FRIDAY
MORNING AND LINGERING INTO SATURDAY. GUIDANCE INDICATES A BRIEF
LULL IN PRECIPITATION IS POSSIBLE LATE FRIDAY NIGHT AS THE
SURFACE LOW LIFTS AND INITIAL SHORTWAVE EXITS. A SECONDARY WAVE
SATURDAY MORNING MAY REINVIGORATE LIGHT SHOWERS BEFORE COVERAGE
WANES SATURDAY AFTERNOON.
BEST COVERAGE FRIDAY AND FRIDAY NIGHT WILL FAVOR AREAS SOUTH AND
EAST OF PITTSBURGH, WHERE FORCING IS BETTER NEAR THE LOW.
ADDITIONAL SHOWERS ON SATURDAY WILL BE LIGHT. HIGHEST QPF OF
AROUND AN INCH WILL TARGET THE WV/PA RIDGES. PROBABILITIES OF
>1" ARE AROUND 30-40% FOR THOSE LOCATIONS. AREAS ALONG ZZV TO
PIT TO DUJ SHOULD GENERALLY SEE LESS THAN 0.5" THROUGH SATURDAY.
BELOW-AVERAGE DAYTIME HIGHS WITH NEAR-AVERAGE OVERNIGHT LOWS
WILL CONTINUE THROUGH THE SHORT TERM AS CLOUDY AND WET WEATHER
CONTINUES.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
KEY MESSAGES:
- DRIER WEATHER EXPECTED BEGINNING SATURDAY NIGHT
- WARMING TEMPERATURES THROUGH NEXT WEEK
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ENSEMBLE GUIDANCE CONTINUES TO FAVOR DEEP EASTERN CONUS
TROUGHING THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. HEIGHTS
SHOULD BEGIN TO RISE BY MONDAY, WITH UPPER RIDGING FULLY
OVERHEAD BY MIDWEEK.
UPPER TROUGH AXIS SHOULD LIE JUST EAST OF THE AREA ON SUNDAY.
A SHORTWAVE TRAVERSING THE NORTHWEST FLOW MAY BE ENOUGH TO SPAWN
A FEW ISOLATED SHOWERS DURING THE DAY, BUT THE PROBABILITY
REMAINS LOW. OTHERWISE, MAINLY DRY AND COOL WEATHER WILL
CONTINUE.
RISING HEIGHTS AND DRY WEATHER MONDAY WILL FAVOR A WARMING TREND
THAT WILL FINALLY USHER IN SUMMER-LIKE TEMPERATURES AND MOSTLY
SUNNY CONDITIONS. MUCH OF THE REGION OUTSIDE THE RIDGES AND I-80
CORRIDOR SHOULD NEAR 80F BY TUESDAY, WITH A 75% OR HIGHER
CHANCE OF HITTING 80F ON WEDNESDAY. HOWEVER, THIS PATTERN MAY
ALSO BRING A BOUT OF STRONG TO SEVERE WEATHER MID-WEEK AS THE
RIDGE BREAKS DOWN. THIS WILL BE SOMETHING TO WATCH FOR IN THE
COMING DAYS.
AVIATION /06Z THURSDAY THROUGH MONDAY/
VEERING BOUNDARY LAYER WIND AS MID-LEVEL TROUGH CONTINUES TO
SHIFT EAST OF THE REGION IS EXPECTED TO CONTINUE WEAK DRY
ADVECTION DURING THE EARLY MORNING HOURS TODAY. THE SUBTLE SHIFT
WILL LIFT IFR/LIFR CIGS AND ERODE POCKETS OF DRIZZLE AS IT
CONTINUES TO TREK WEST TO EAST. THE BIGGEST UNCERTAINTY BEYOND
THE TIMING OF THIS IMPROVEMENT IS WHETHER ENOUGH EROSION OCCURS
OF THE STRATUS DECK TO BRIEFLY CLEAR SKIES; IF THIS OCCURS,
ENOUGH RADIATIONAL COOLING COULD CREATE RAPID ONSET OF FOG/LIFR
STRATUS. FURTHER COMPLICATING MATTERS IS THE PRESENCE OF HIGH
CLOUDS THAT MAY STUNT SUCH COOLING EVEN IF CLEARING OCCURS. LOW
CONFIDENCE IN THE RIGHT COMBINATION OF FOG-PRODUCING CONDITIONS
OUTSIDE OF ZZV/HLG PREVENTED TAF MENTION WHILE ATTEMPTING TO
CAPTURE TRENDS FOR MORNING IMPROVEMENTS WITH WSW/SW WIND SHIFT.
SUBSIDENCE AND DRY ADVECTION PLUS DIURNAL MIXING CREATES HIGH
CONFIDENCE IN VFR CONDITIONS AFTER 18Z AS CIGS RISE THROUGH THE
DAY. ANY SITES THAT DO SEE VFR CONDITIONS BY 12/13Z LIKELY WILL
STILL SEE DIURNAL CU LIFTING THROUGH MVFR LAYER BETWEEN 14Z-17Z.
OCCASIONAL GUSTS UP TO 20KTS CAN'T BE RULED OUT THIS AFTERNOON
BEFORE QUIETING OVERNIGHT.
OUTLOOK...
THE NEXT LOW PRESSURE SYSTEM WILL RETURN RAIN CHANCES AND
AREAWIDE RESTRICTIONS FRIDAY, WITH MODELS FAVORING HIGHEST
AVIATION IMPACTS EAST OF I-79. TRANSITION TO NW FLOW WILL
MAINTAIN PERIODS OF MVFR CLOUDS WITH SHOWERS SATURDAY BEFORE
HIGH PRESSURE AND DRY ADVECTION FAVOR VFR SATURDAY NIGHT.
THERE IS A HIGH PROBABILITY FOR A PROLONGED PERIOD OF VFR AND
DRY WEATHER SUNDAY INTO EARLY NEXT WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...RACKLEY
NEAR TERM...RACKLEY/AK
SHORT TERM...RACKLEY
LONG TERM...RACKLEY/FRAZIER
AVIATION...FRAZIER
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