579
FXUS61 KPBZ 061109
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
709 AM EDT WED MAY 6 2026
WHAT HAS CHANGED
UPDATED AVIATION FORECAST, OTHERWISE NO SIGNIFICANT CHANGES
WERE MADE TO THE FORECAST.
KEY MESSAGES
1) MORNING RAIN WILL CLEAR TO COOLER AND DRIER WEATHER THROUGH
FRIDAY, BEFORE MORE RAIN CHANCES RETURN OVER THE WEEKEND.
2) FROST REMAINS POSSIBLE TONIGHT AND FRIDAY MORNING.
DISCUSSION
KEY MESSAGE 1...
RAIN IS EXPECTED TO PERSIST THROUGH THIS MORNING, BEFORE
CLEARING INTO THE AFTERNOON. WITH NO ADDITIONAL INSTABILITY
EXPECTED BETWEEN NOW AND LATE-MORNING, RAIN WILL LIKELY REMAIN
STRATIFORM, WITH NO ADDITIONAL CONVECTIVE OR FLOODING CONCERNS.
THE HEAVIEST TOTALS HAVE BEEN OBSERVED UP IN MERCER COUNTY
(~0.5" AS OF 1AM); ENSEMBLES SUGGEST MOST LIKELY TOTALS BY THE
END OF THE EVENT IN THE I-80 CORRIDOR WILL BE AROUND 0.75", WITH
A 30% CHANCE OF >1". CHANCES OF >1" RAPIDLY DECREASE TO THE
SOUTH AND EAST, WITH CHANCES GENERALLY >15% ELSEWHERE.
DRIER AND COOLER WEATHER IS EXPECTED THURSDAY AND FRIDAY
COURTESY OF THE POST-COLD-FRONTAL ENVIRONMENT AND A BRIEF BOUT
OF HIGH PRESSURE. CHANCES OF RAIN INCREASE AGAIN LATE FRIDAY
AND THROUGH SUNDAY NIGHT. CHANCE FRIDAY AND SATURDAY WILL BE
COURTESY OF A COUPLE OF WEAKER SHORTWAVES. THE BRUNT OF RAINFALL
ACCUMULATIONS IS FORECAST SUNDAY WITH THE NEXT LOW PRESSURE
PASSAGE AND COLD FRONT. CHANCES OF >1" RIGHT NOW ARE GENERALLY
<20% AND THE SYSTEM SEEMS GENERALLY PROGRESSIVE IN MOST
SCENARIOS, WHICH WOULD KEEP FLOODING CONCERNS LOW.
KEY MESSAGE 2...
THERE IS MEDIUM TO HIGH CONFIDENCE IN CLOUDS SCATTERING SOME
OVERNIGHT TONIGHT NORTH OF PITTSBURGH AS HIGH PRESSURE
GRADUALLY BUILDS IN. WITH IT, THE PRESSURE GRADIENT WILL ALSO
RELAX AND CALM OVERNIGHT WINDS WITH DECOUPLING. NBM PROBABILITIES
OF TEMPS LESS THAN 37F TONIGHT ARE GENERALLY 30% TO 50% NORTH
OF PITTSBURGH, BUT CHANCES OF A FREEZE ARE <5%. THUS, THERE IS A
LOW PROBABILITY OF A FROST TONIGHT. MOST INSTANCES WILL LIKELY
BE ISOLATED AND PATCHY DEPENDING ON MICRO- SCALE TERRAIN
INFLUENCE.
A SIMILAR REGIME WILL LINGER FRIDAY MORNING, WITH A HIGHER
CHANCE OF LOW CLOUDS CLEARING AREA-WIDE. THIS WILL CORRELATE TO
A BIT HIGHER CHANCES OF A FROST, WITH REGIONS NORTH OF
PITTSBURGH AND THE HIGHER TERRAIN OF PA/WV SEEING A 50% TO 80%
CHANCE OF LESS THAN 37F, AND THE REST OF THE REGION GENERALLY
BETWEEN 10% TO 35%. CHANCES OF A FREEZE ARE, AGAIN, LOW FOR
NOW, HIGHEST AT 10% TO 25% FOR FOREST COUNTY AND EASTERN TUCKER
COUNTY.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
THOUGH THE HEAVIER RAIN EXISTS EAST BY 14Z, RESIDUAL LIGHT
RAIN/DRIZZLE PLUS DELAY IN THE SURFACE FRONTAL PASSAGE WILL HOLD
AND FURTHER SPREAD IFR TO LOCALLY LIFR CONDITIONS THIS MORNING.
DRY ADVECTION AND SUBSIDENCE WORKING FROM THE WEST OFFERS
CEILING IMPROVEMENTS STARTING IN THE LATE MORNING HOURS THROUGH
THIS EVENING, WITH MOISTURE CONVERGENCE DELAYING VFR TIMING AT
THE SOUTHEASTERN-MOST SITES (KLBE/KMGW).
GRADUAL CLEAR OF CLOUDS BELOW 5KFT IS EXPECTED THIS EVENING,
WITH CIRRUS EXITING THEREAFTER. HI-RES MODELING IS VERY BEARISH
(LESS THAN 10%) ON FOG DEVELOPMENT, THE LATE ARRIVAL OF DRIER
AIR NEAR KMGW PLUS OVERNIGHT CLEAR COULD ALLOW FOR A BRIEF
VISIBILITY DROPS NEAR DAWN.
OUTLOOK...
ISOLATED SHOWERS COULD DEVELOP WITH PEAK HEATING THURSDAY
AFTERNOON AREAWIDE WITH ADDITIONAL SHOWERS (AND LOW PROBABILITY
RESTRICTIONS) POSSIBLE OVERNIGHT NORTH OF I-80. THEN, RAIN AND
RESTRICTIONS DEVELOP FRIDAY AFTERNOON INTO SATURDAY, STARTING A
TREND OF INTERMITTENT PERIODS OF RAIN/RESTRICTIONS ASSOCIATED
WITH PASSING SHORTWAVES WITHIN THE BROAD GREAT LAKES TROUGHING.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...MILCAREK
AVIATION...FRAZIER
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