531
FXUS61 KPBZ 020741
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
341 AM EDT TUE SEP 2 2025
SYNOPSIS
WIDESPREAD RAIN CHANCES RETURN THURSDAY WITH THE
APPROACH AND PASSAGE OF A COLD FRONT. GUSTY WINDS AND ISOLATED
STORMS ARE ALSO POSSIBLE WITH THE PASSAGE OF THE FRONT. COOLER
CONDITIONS ARE EXPECTED OVER THE WEEKEND.
NEAR TERM /THROUGH TODAY/
KEY MESSAGES:
- PATCHY RIVER VALLEY FOG IS POSSIBLE
- ISOLATED SHOWERS ACTIVITY NEAR THE RIDGES THIS AFTERNOON
---------------------------------------------------------------
GOES-19 NIGHTTIME MICROPHYSICS IMAGERY DEPICTS BROKEN MID-LEVEL
CLOUDS OVER PORTIONS OF THE REGION EARLY THIS MORNING. AREAS
WITH PROLONG CLEARING MAY PROMPT PATCHY RIVER VALLEY FOG BEFORE
DAWN.
AFTER SUNRISE, RIVER VALLEY FOG WILL DISSIPATE WITH SURFACE
HEATING/MIXING. ISOLATED, TERRAIN-DRIVEN SHOWERS ARE POSSIBLE IN
THE LAUREL HIGHLANDS THIS AFTERNOON (BETWEEN 1PM AND 5PM) WITH
SHALLOW INSTABILITY. THIS IS CONSIDERED A LOW CHANCE OF
OCCURRENCE (10-15%). OTHERWISE, MOSTLY DRY CONDITIONS ACROSS THE
REGION.
SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/
KEY MESSAGES:
- PRE-FRONTAL RAIN SHOWERS POSSIBLE WEDNESDAY EVENING
----------------------------------------------------------------
BY EARLY WEDNESDAY MORNING, A LOW PRESSURE SYSTEM WILL
STRENGTHEN NORTH OF MINNESOTA AND MOVE TOWARDS THE GREAT LAKES.
AS SOUTHWEST FLOW INCREASES AHEAD OF THIS DISTURBANCE AND BRINGS
MOISTURE INTO THE REGION WEDNESDAY AFTERNOON, EXPECT CLOUDS AND
ISOLATED SHOWERS TO DEVELOP IN SOME AREAS. LOCATIONS SOUTH OF
PITTSBURGH HAVE THE HIGHEST CHANCE, THOUGH STILL LOW (20-30%),
OF SEEING SHOWERS.
WITH INCREASING WARM ADVECTION AHEAD OF THE APPROACHING
DISTURBANCE, EXPECT AFTERNOON HIGH TEMPERATURE TO BE NEAR
AVERAGE.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
KEY MESSAGES:
- SHOWERS, THUNDERSTORMS, AND GUSTY WINDS ARE EXPECTED WITH A
COLD FRONT THURSDAY
- SECONDARY FRONT MAY CREATE ADDITIONAL SHOWERS ON FRIDAY
- COOLER WEATHER RETURNS OVER THE WEEKEND
-------------------------------------------------------------------
BY LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING, THE
PREVIOUSLY MENTIONED LOW PRESSURE SYSTEM IN THE SHORT TERM
DISCUSSION IS EXPECTED TO MOVE ACROSS LAKE SUPERIOR, WITH ITS
TRAILING COLD FRONT EXTENDED SOUTH INTO CENTRAL MICHIGAN AND
INDIANA. STRENGTHENING SOUTHWEST FLOW ALOFT WILL KEEP THURSDAY
MORNING TEMPERATURES NEAR AVERAGE, WHILE CLOUDS INCREASE FROM
THE WEST.
RAIN CHANCES INCREASE AFTER 6AM THURSDAY AS THE APPROACHING
COLD FRONT MOVES INTO EASTERN OHIO AND PROGRESSES INTO WESTERN
PENNSYLVANIA BY LATE MORNING OR EARLY AFTERNOON. THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG THE FRONT, SUPPORTED BY STRONG
WIND SHEAR BUT LIMITED INSTABILITY (GENERALLY LESS THAN
500J/KG) DUE TO INCREASING MOISTURE AT THE SURFACE. MACHINE
LEARNING GUIDANCE SUGGESTS A 5-15% CHANCE OF STRONGER STORMS IN
SOME SCENARIOS, WHICH WILL NEED TO BE MONITORED OVER THE NEXT 48
HOURS. THE EXACT TIMING OF THE FRONT WILL BE CRITICAL IN
DETERMINING HOW MUCH INSTABILITY CAN BUILD ON THURSDAY.
RAINFALL TOTALS ARE EXPECTED TO RANGE FROM 0.35" TO 0.65", WITH
LOCALIZED SWATHS OF HIGHER AMOUNTS WHERE THUNDERSTORMS OCCUR.
GIVEN THE RECENT STRETCH OF DRY WEATHER, THE RISK FOR FLOODING
REMAINS LOW.
INCREASING DRY AIR ALOFT LATE THURSDAY WILL DIMINISH THE CHANCE
OF HEAVY RAINFALL. HOWEVER, STRAY SHOWERS MAY LINGER EAST OF
PITTSBURGH.
BEHIND THE FRONT, THE BROAD DISTURBANCE STRETCHING FROM THE
NORTHERN PLAINS TO NEW ENGLAND IS EXPECTED TO STALL. A PASSING
SHORTWAVE AND SECONDARY FRONT MOVING THROUGH THE REGION FRIDAY
INTO SATURDAY MAY TRIGGER ADDITIONAL CONVECTION.
ADVANCEMENT OF THE TROUGH AND INCREASING NORTHERLY FLOW OVER THE
WEEKEND WILL LIKELY INCREASE THE CHANCES OF COOLER THAN AVERAGE
TEMPERATURES.
AVIATION /07Z TUESDAY THROUGH SATURDAY/
HIGH PRESSURE CENTERED OVER NEW ENGLAND WILL RESULT IN MOSTLY
DRY WEATHER AND LIGHT EASTERLY WIND THROUGH THE TAF PERIOD.
LINGERING MOISTURE BETWEEN 6-10KFT COMBINED WITH DIURNAL CU
DEVELOPMENT FAVORS PERIODS OF SCATTERED TO BRIEFLY BROKEN VFR
CIGS IN THAT HEIGHT RANGE.
HI-RESOLUTION MODELING SUGGESTS THAT THE COMBINATION OF HEATING
AND EASTERLY UPSLOPE FLOW MAY BE ENOUGH TO FOSTER A TUESDAY
AFTERNOON SHOWER EAST OF KPIT (20-40%). ANY CONVECTION IS LIKELY
TO BE VERY ISOLATED AND TEND TO STAY EAST OF THE FORECAST
REGION/LAUREL HIGHLANDS.
OUTLOOK.
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH WEDNESDAY, THOUGH AN
APPROACHING UPPER TROUGH MAY AID ENOUGH MOISTURE ADVECTION TO
GENERATE AN ISOLATED AFTERNOON SHOWER SOUTH OF KPIT.
AN UPPER LEVEL TROUGH AND SURFACE COLD FRONT IS HIGHLY LIKELY TO
PRODUCE WIDESPREAD RAIN WITH LOW-PROBABILITY THUNDERSTORMS
STARTING EARLY THURSDAY MORNING BEFORE TAPERING OFF EARLY
FRIDAY MORNING. EARLY MODEL ANALYSIS SUGGESTS A 40-60 PERCENT
PROBABILITY FOR MVFR OR LOWER CIGS ASSOCIATED WITH THE RAIN
THURSDAY, WITH CONDITIONS POTENTIALLY IMPROVING WEST TO EAST
SHORTLY AFTER FRONTAL PASSAGE.
ADDITIONAL SHORTWAVE MOVEMENT MAY OFFER ADDITIONAL RAIN AND
RESTRICTIONS CHANCES LATE FRIDAY INTO SATURDAY BEFORE DRY
WEATHER DEVELOPS TO START THE NEXT WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...HEFFERAN
NEAR TERM...HEFFERAN
SHORT TERM...HEFFERAN
LONG TERM...HEFFERAN
AVIATION...FRAZIER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page