321
FXUS61 KPBZ 281800
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
200 PM EDT WED MAY 28 2025
SYNOPSIS
LIGHT RAIN AND/OR DRIZZLE CONTINUES TODAY AS A LOW PRESSURE
SYSTEM TRACKS NORTH. PROBABILITIES ARE INCREASING IN SEEING
ANOTHER ROUND OF RAIN SHOWERS FRIDAY AND SATURDAY WHILE
TEMPERATURE FALLS BELOW AVERAGE. LOOK FOR MORE SUMMER LIKE
TEMPERATURE TO DEVELOP NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- RAIN AND DRIZZLE CONTINUES TODAY, BECOMING MORE SCATTERED THIS
AFTERNOON
- RAIN DISSIPATES THIS EVENING, WITH MAINLY DRY CONDITIONS
OVERNIGHT
- FOGGY CONDITIONS COULD DEVELOP LATE TONIGHT
-------------------------------------------------------------------
LIGHT RAIN AND DRIZZLE CONTINUE TODAY AS A WEAK SURFACE LOW
TRACKS NORTH. PRECIPITATION COVERAGE IS EXPECTED TO BECOME MORE
SCATTERED THIS AFTERNOON, EVENTUALLY DISSIPATING THIS EVENING.
LIMITED INSTABILITY ALOFT AND AT THE SURFACE THIS AFTERNOON
WILL KEEP A NON- ZERO CHANCE FOR THUNDERSTORMS. THIS THREAT IS
LOW ENOUGH TO PRECLUDE MENTION IN THE FORECAST.
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 /THURSDAY THROUGH SATURDAY/
KEY MESSAGES:
- DRY WEATHER AND BRIEF WARMING EXPECTED THURSDAY.
- PATTERN SHIFT WITH NEXT LOW PRESSURE SYSTEM STARTING FRIDAY.
----------------------------------------------------------------
QUASI-ZONAL TO SOUTHWEST FLOW OVER SURFACE HIGH PRESSURE WILL
GENERALLY SUPPORT DRY WEATHER AND SEASONABLE TEMPERATURE
THURSDAY. HOWEVER, GIVEN LITTLE CHANGE IN BOUNDARY LAYER
MOISTURE FROM WEDNESDAY, AN ISOLATED AFTERNOON SHOWER CAN'T BE
RULED OUT THURSDAY DUE TO EMBEDDED VORT ADVECTION IN THE SW FLOW
THAT GLOBAL MODELS MAY HAVE MORE DIFFICULTY IN RESOLVING.
THE DEVELOPMENT AND DEEPENING OF A LOWER OHIO RIVER VALLEY UPPER
TROUGH WILL OCCUR THURSDAY EVENING INTO FRIDAY, SHIFTING SLOWLY
EASTWARD THROUGH THE PERIOD. THIS TROUGH SHOULD SPUR SURFACE
CYCLOGENESIS (WHICH MAY BE AIDED BY ONGOING CONVECTION) THAT
LOOKS TO DEEPEN SLIGHTLY AND TRACK GENERALLY ENE. VARIABILITY IN
THE UPPER TROUGH DEPTH AND SURFACE LOW POSITIONING CONTINUES TO
LOWER CONFIDENCE IN THE TIMING AND AREAL COVERAGE OF THE
ASSOCIATED RAINFALL FOR THE UPPER OHIO RIVER VALLEY. THE MAIN
FOCUS IN MESSAGING IS THAT THIS PERIOD WILL SIGNAL A SHIFT
TOWARDS EASTERN CONUS TROUGHING THAT FAVORS PERIODIC
PRECIPITATION CHANCES AND FALLING TEMPERATURE.
LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/
KEY MESSAGES:
- BELOW AVERAGE TEMPERATURES CONTINUE THIS WEEKEND, WARMING NEXT
WEEK
- LIGHT RAIN SHOWERS FAVORED SATURDAY
-------------------------------------------------------------------
ENSEMBLE MEANS HAVE CONTINUED THEIR TREND TOWARD FAVORING DEEPER
AND SLIGHTLY SLOWER EASTERN CONUS TROUGHING THAT WILL CREATE
PERIODS OF RAIN SHOWERS SATURDAY WITH LIMITED HEATING. SEEING
SOME CONSENSUS ON MID-DAY 850MB TEMPS AROUND 7 DEGREES C LEAD TO
A MORE BEARISH TEMPERATURE FORECAST FOR SATURDAY (LEANING TOWARD
EUROPEAN MODEL MEANS AND LOCAL STUDIES). THIS NW FLOW PATTERN
LIKELY WILL FAVOR GREATER CLOUD COVER THAN MODEL MEANS SUGGEST
AS WELL AS MORE SCATTERED PRECIPITATION, WHICH WOULD FURTHER
LIMIT DIURNAL HEATING SATURDAY.
THE MODEL CONSENSUS IS FOR THE UPPER TROUGH AXIS TO BE EAST OF
THE REGION BY SUNDAY, ALLOWING FOR DRIER WEATHER AND SLIGHT
TEMPERATURE IMPROVEMENTS. CONFIDENCE RAISES SIGNIFICANTLY FOR
EARLY NEXT WEEK TO SEE LARGE HEIGHT RISES AND POTENTIAL RIDGE
DEVELOPMENT THAT LENDS TO ABOVE NORMAL TEMPERATURE AS EARLY AS
MONDAY THAT PERSISTS MUCH OF THE WEEK. IF THIS PATTERN DEVELOPS,
LOOK FOR SUMMER-LIKE TEMPERATURE READINGS BY MID WEEK BUT ALSO
THE POTENTIAL FOR RIDGE BREAKDOWNS THAT COULD LEAD TO A SEVERE
WEATHER OUTBREAK.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
SCATTERED RAIN CHANCES WILL CONTINUE THROUGH 00Z WITH A PASSING
SHORTWAVE. INCOMING DRY AIR FROM THE SOUTHWEST AFTER 00Z WILL
LIKELY DIMINISH PRECIP CHANCES. HOWEVER, WITH SUFFICIENT
AVAILABLE MOISTURE, LIFR/IFR CIGS ARE LIKELY TO CONTINUE TONIGHT
INTO EARLY TOMORROW MORNING.
THERE IS A POTENTIAL FOR FOG FORMATION BETWEEN 06Z TO 13Z SOUTH
OF PIT AND NEAR ZZV WITH LIGHT WINDS, WARM ADVECTION ONGOING,
AND SUFFICIENT MOISTURE FOR RAIN OVER THE LAST 36 HOURS.
HIGH RESOLUTION MODEL SOUNDINGS DEPICT CIG IMPROVEMENT AFTER 18Z
THURSDAY, HIGH MVFR TO VFR IS EXPECTED.
THE POTENTIAL FOR RIVER VALLEY FOG IS NOTED EARLY FRIDAY
MORNING IN MODEL SOUNDINGS.
OUTLOOK...
UPPER TROUGH REMAINS IN PLACE THROUGH THE WEEKEND. VFR CEILINGS
EXPECTED FRIDAY AFTERNOON INTO SATURDAY. HOWEVER, MVFR
CONDITIONS CAN'T BE RULED OUT WITH SHOWER ACTIVITY. NORTHWEST
WIND GUSTS ON SATURDAY IN THE 25 TO 30 KNOT RANGE ARE EXPECTED.
HIGH PRESSURE BUILDING IN SUNDAY SHOULD RESULT IN VFR AND MAINLY
CLEAR CONDITIONS.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...RACKLEY
NEAR TERM...RACKLEY
SHORT TERM...RACKLEY
LONG TERM...RACKLEY/FRAZIER
AVIATION...HEFFERAN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page