716
FXUS61 KPBZ 081450
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1050 AM EDT THU MAY 8 2025
SYNOPSIS
A PASSING COLD FRONT TODAY WILL RETURN SHOWERS AND ISOLATED
STORMS SOUTH OF PITTSBURGH. A DRY WEATHER PATTERN WITH WARMING
TEMPERATURE IS LIKELY THIS WEEKEND INTO EARLY NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- PASSING COLD FRONT RETURNS RAIN AND ISOLATED STORM CHANCES
THIS AFTERNOON/EVENING
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MORNING FOG HAS DISSIPATED WITH ONSET OF MIXING AND THE LOW
STRATUS DECK NORTH OF PITTSBURGH HAS NOW MOSTLY MIXED OUT. A
SURFACE COLD FRONT HAS JUST ABOUT CLEARED THE FORECAST AREA WITH
NORTHERLY WIND TAKING OVER IN ITS WAKE. LOW LEVEL COLD
ADVECTION COUPLED WITH A SECONDARY SURFACE BOUNDARY SAGGING
SOUTH OUT OF LAKE ERIE IS SUPPORTING ADDITIONAL CLOUD COVERAGE
AND SHOWERS. AS A RESULT, HIGHS WILL BE COOLEST ALONG THE I-80
CORRIDOR WITH SOME OF FAR NORTHERN MERCER, VENANGO, AND FOREST
COUNTIES FAVORED TO HOLD BELOW 60F; FROM PITTSBURGH AND SOUTH,
PROBS FOR 70F ARE AS HIGH AS 80%.
12Z CAMS SUPPORT A FEW SHOWERS MAKING IT INTO OUR NORTHERN ZONES
THIS MORNING WITH LOW PROBABILITY (20-30%) ADDITIONAL
REDEVELOPMENT THIS AFTERNOON ALONG WEAK CONVERGENCE. WHERE
DEVELOPMENT IS MORE LIKELY WILL BE AFTER 1PM SOUTH OF PITTSBURGH
ALONG THE COLD FRONT, AND PERHAPS MORE SO FOCUSED SOUTH OF I-70
GIVEN PROGGED FRONTAL PLACEMENT. LATEST RUNS HAVE EXHIBITED A
BIT OF AN UPTICK IN INSTABILITY WITH POINT SOUNDINGS RANGING
ANYWHERE FROM 700-1000 J/KG OF SBCAPE. SAID INSTABILITY PROFILE
ISN'T PARTICULARLY WIDE AT ANY LEVEL WHICH SHOULDN'T SUPPORT
VIGOROUS UPDRAFTS, AND WEAK FLOW UP TO 500 MB ONLY TOPPING OUT
AROUND 30 KNOTS ISN'T PROVIDING MUCH SHEAR RELATED ASSISTANCE
WITH EBWD VALUES AROUND 20-25 KNOTS. THUS, THE SEVERE WEATHER
THREAT IS LOW TODAY, BUT CAN'T RULE OUT SOME LOCALLY GUSTY WIND
IN THE STRONGEST STORMS WITH MODEST DCAPE VALUES AROUND 400-500
J/KG.
OVERNIGHT LOWS WILL DIP DOWN A TOUCH IN THE WAKE OF THE FRONT
WITH COLD ADVECTION IN LIGHT NORTHERLY FLOW. PROBS FOR <40F ARE
40-60% ALONG I-80 WITH UPPER 40S FAVORED ELSEWHERE. CLOUD
COVERAGE IS FAVORED TO BE BLANKETED SOUTH OF A LINE FROM ROUGHLY
FROM DUBOIS TO PITTSBURGH TO WHEELING, BUT THAT WILL BE
DEPENDENT ON HOW QUICKLY MID- LEVEL DRY AIR CAN ADVECT IN; A
MORE PESSIMISTIC SOLUTION EXTENDS THAT LINE BACK AS FAR
NORTHWEST AS FRANKLIN OR MORE OPTIMISTIC AS FAR EAST AS LATROBE.
SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/
KEY MESSAGES:
- DRY AND BELOW AVERAGE TEMPERATURES EXPECTED FRIDAY/FRIDAY
NIGHT
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INCREASING MID- AND UPPER-LEVEL SUBSIDENCE IS EXPECTED TO KEEP
MOST OF THE REGION DRY ON FRIDAY. SOME LINGERING EARLY MORNING
SHOWERS MAY PERSIST EAST OF PITTSBURGH, BUT MEASURABLE
PRECIPITATION WILL PRIMARILY BE CONFIDED TO CENTRAL PENNSYLVANIA
AND THE EAST COAST, ASSOCIATED WITH AN INVERTED TROUGH.
WITH COLD AIR ADVECTION ALOFT AND NORTHERLY TO NORTHEAST FLOW,
AFTERNOON HIGH TEMPERATURE ON FRIDAY ARE PROJECTED TO RUN 5 TO
10 DEGREES BELOW NORMAL.
SKIES ARE LIKELY TO CLEAR FRIDAY NIGHT, ALLOWING TEMPERATURES TO
FALL INTO THE MID TO UPPER-30S DUE TO RADIATIONAL COOLING.
PATCHY FROST IS POSSIBLE, PARTICULARLY ACROSS THE RIDGES AND
AREAS NORTH OF I-80. HOWEVER, THE PROBABILITY OF TEMPERATURES
DROPPING BELOW 35 DEGREES IS RELATIVELY LOW - GENERALLY BETWEEN
10% TO 20% - SO THE NEED FOR FROST HEADLINES REMAINS MINIMAL.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
KEY MESSAGES:
- WARMER FOR THE WEEKEND INTO EARLY NEXT WEEK
- RAIN CHANCES RETURN BY MID-WEEK
- POTENTIAL FOR STRONG TO SEVERE STORMS LATE WEEK
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CONFIDENCE REMAINS HIGH THAT QUIET AND WARM CONDITIONS WILL
PREVAIL OVER THE WEEKEND, AS A RIDGE OF HIGH PRESSURE BUILDS
OVER THE GREAT LAKES WHILE A DEPARTING TROUGH MOVES INTO THE NEW
ENGLAND REGION. BY SUNDAY, TEMPERATURES ARE FORECAST TO RUN
ABOUT 10 DEGREES ABOVE NORMAL.
RAIN CHANCES ARE EXPECTED TO INCREASE LATE TUESDAY INTO
WEDNESDAY AS A CUT-OFF LOW OVER THE MISSISSIPPI RIVER VALLEY
LIFTS NORTHWARD, COINCIDING WITH THE APPROACH OF A DEEP TROUGH
ALONG THE WEST COAST.
LOOKING AHEAD TO LATE WEEK, THERE IS AN EMERGING SIGNAL FOR THE
POTENTIAL OF SEVERE THUNDERSTORMS AS A LOW-PRESSURE SYSTEM
TRACKS INTO THE GREAT LAKES, INTERACTING WITH A WARM AND MOIST
AIRMASS.
AVIATION /15Z THURSDAY THROUGH MONDAY/
VALLEY FOG HAS DEVELOPED THIS MORNING AND IS RESULTING IN
OCCASIONAL DROPS IN VISIBILITY AT TERMINALS ADJACENT TO RIVERS.
THIS FOG SHOULD DISSIPATE BY OR SHORTLY AFTER 13Z, GIVING WAY TO
VFR VISIBILITIES THROUGH THE REST OF THE DAY.
A STUBBORN LIFR STRATUS DECK IS CURRENTLY DRAPED ACROSS NORTHERN
OH AND NORTHWEST PA, IMPACTING BVI, FKL, AND DUJ TO START THE
PERIOD. THERE IS SOME MINOR CONCERN THAT THIS DECK WILL CREEP
SOUTH ENOUGH TO BRIEFLY IMPACT PIT OVER THE NEXT COUPLE HOURS,
BUT CONFIDENCE IN THAT OCCURRING IS LOW AND THE ONSET OF DAYTIME
HEATING AND MIXING SHOULD HELP THAT DECK RETREAT NORTHWARD. AT
AFOREMENTIONED TERMINALS UNDER THE STRATUS DECK, GRADUAL
LIFTING TO IFR AND THEN MVFR IS EXPECTED THROUGH THIS MORNING,
POTENTIALLY BACK TO VFR BY AFTERNOON.
WHILE VFR IS GENERALLY EXPECTED TO PREVAIL ELSEWHERE ACROSS THE
AREA THROUGHOUT THE PERIOD, RESTRICTION POTENTIAL DOES INCREASE
THIS AFTERNOON/EVENING SOUTH AND EAST OF PIT (I.E. MGW/LBE) AS
SHOWERS AND A FEW THUNDERSTORMS FIRE ALONG A COLD FRONT.
CEILINGS LOWER INTO MVFR/IFR RANGE TONIGHT, GENERALLY SOUTHEAST
OF A LINE FROM ZZV TO PIT TO DUJ.
OUTLOOK...
CEILINGS SHOULD IMPROVE BACK TO VFR BY FRIDAY AFTERNOON.
GENERAL VFR THEN PREVAILS THROUGH THE WEEKEND WITH HIGH
PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...HEFFERAN
NEAR TERM...MLB
SHORT TERM...HEFFERAN
LONG TERM...HEFFERAN
AVIATION...CERMAK/RACKLEY
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