178
FXUS61 KPBZ 292336
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
736 PM EDT THU MAY 29 2025
SYNOPSIS
LOW PRESSURE TRACKING ACROSS WEST VIRGINIA WILL BRING SHOWERS
AND POSSIBLY A THUNDERSTORM FRIDAY, ESPECIALLY FROM PITTSBURGH
SOUTHWARD. SHOWERS WILL LINGER INTO SATURDAY AS ANOTHER LOW
PRESSURE AREA DROPS OUT OF THE GREAT LAKES. COOL AND BLUSTERY
WEATHER IS EXPECTED SATURDAY AND READINGS WILL BE ABOUT 10
DEGREES BELOW NORMAL.
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
KEY MESSAGES:
- MINIMAL RAIN CHANCES THIS EVENING
- TEMPERATURES AROUND NORMAL.
-------------------------------------------------------------------
UPDATE...
A WEAK CROSSING SHORTWAVE WILL CONTINUE TO RESULT IN ISOLATED
SPRINKLES/SHOWERS ACROSS THE REGION THIS EVENING. OTHERWISE,
DRY WEATHER IS EXPECTED OVERNIGHT AFTER THE WAVE EXITS. PATCHY
FOG IS POSSIBLE OVERNIGHT, ESPECIALLY IN AND NEAR THE RIVER
VALLEYS, THOUGH INCREASING MID LEVEL CLOUDS OVERNIGHT SHOULD
HELP TO LIMIT THE COVERAGE OF THE FOG.
PREVIOUS DISCUSSION... MID-LEVEL FLOW ACCELERATES OVERNIGHT
AHEAD OF THE NEXT WAVE, BUT THE BEST FORCING DOES NOT ARRIVE
UNTIL AFTER SUNRISE. MOSTLY BROKEN CLOUD DECKS WILL PREVAIL WITH
TEMPERATURES RIGHT AROUND SEASONAL NORMALS.
SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/
KEY MESSAGES:
- WIDESPREAD RAINFALL RETURNS FRIDAY ESPECIALLY PITTSBURGH ON
SOUTH
- THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL IN NORTHERN WV
----------------------------------------------------------------
POSITIVELY TILTED TROUGH OVER THE GREAT LAKES WILL PIVOT AND
SWING TOWARD THE UPPER OHIO VALLEY ON FRIDAY. DURING THIS TIME
IT WILL PHASE WITH THE BROADER TROUGH DIGGING OUT OF CANADA,
DEEPENING AS IT CROSSES INTO PA AND SHIFTS TOWARD NEW ENGLAND.
WITH LEFT EXIT JET SUPPORT AND 700MB FRONTOGENESIS INTENSIFYING
FOR A PERIOD OVER NORTHERN WV/SOUTHWESTERN PA, THINK IT IS
REASONABLE TO SEE A PERIOD OF MODERATE RAINFALL, THOUGH PWATS
WON'T BE CLIMATOLOGICALLY HIGH OVER THE AREA. THAT BEING SAID,
PORTIONS OF NORTHERN WV DID RECEIVE 1.50-3.00" OVER THE LAST 48
HOURS, SO EVEN MODERATE RAINFALL ON SATURATED SOILS COULD POSE A
FLOOD CONCERN. WPC HAS EXPANDED THE SLIGHT RISK OF EXCESSIVE
RAINFALL TO ENCOMPASS THESE AREAS, WHICH SEEMS APPROPRIATE.
HREF PROBABILITIES OF >1.00" IN AN HOUR ARE SMALL (GENERALLY
UNDER 10%), BUT THERE IS A SIGNAL NONETHELESS. AT THIS TIME,
WILL OPT NOT TO HOIST A WATCH BUT WILL HIGHLIGHT THE CONCERN IN
THE HWO.
FARTHER NORTH, THERE IS STILL GOOD CONFIDENCE IN MEASURABLE
RAINFALL, PARTICULARLY FROM A LINE FROM ABOUT ZANESVILLE TO
PITTSBURGH, TO NEAR INDIANA. THERE, MEAN PRECIPITATION THROUGH
FRIDAY NIGHT RANGES FROM 0.25 TO 0.75".
THE LOW WILL MOVE OFF TO THE EAST FRIDAY NIGHT, AS A SECONDARY
WAVE DIVES SOUTHWARD INTO THE BASE OF THE TROUGH. SHOWERY
PRECIPITATION WILL LINGER INTO SATURDAY WITH THE OVERNIGHT COLD
FRONT PASSAGE AND AS COLD NORTHWEST FLOW ALLOWS FOR SOME LAKE
ENHANCEMENT. SUBSIDENCE WILL END PRECIPITATION BY LATE SATURDAY
BUT COLD 850HPA TEMPS NEAR 0-2C WILL KEEP TEMPERATURES BELOW
AVERAGE.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
KEY MESSAGES:
- WARMING TEMPERATURES BEGIN SUNDAY AND CONTINUE THROUGH MIDWEEK
-------------------------------------------------------------------
UPPER TROUGH WILL EVENTUALLY BE REPLACED WITH RIDGING AS WE GO
INTO NEXT WEEK. 500MB HEIGHTS WILL BE AROUND 580DAM+ BY TUESDAY
SUPPORTING A WARMING TREND THROUGH THE PERIOD. BY TUESDAY AND
WEDNESDAY, WE WILL LIKELY SEE TEMPERATURES ABOVE NORMAL. NBM
HAS THE PROBABILITY OF >80 DEGREES NEAR 60% OR ABOVE SAVE FOR
THE TERRAIN. BY WEDNESDAY THERE IS GREATER THAN 70% CHANCE OF
EXCEEDING 85 AREAWIDE.
SUBSIDENCE WILL MAINTAIN DRY CONDITIONS THROUGH THE LONG TERM.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
VFR IS EXPECTED THROUGH MOST OF TONIGHT, WITH MAINLY MID AND
HIGH LEVEL CLOUDS AHEAD OF THE NEXT APPROACHING LOW PRESSURE
SYSTEM. THESE CLOUDS SHOULD HELP LIMIT FOG OVERNIGHT, THOUGH A
FEW AIRPORTS NEAR THE VALLEYS COULD SEE SOME MVFR FOG TOWARD
MORNING. ANY FOG SHOULD DISSIPATE AFTER SUNRISE WITH MIXING,
THOUGH THE CU RULE AND MODEL SOUNDINGS INDICATE A DIURNAL
CUMULUS CLOUD FIELD SHOULD DEVELOP AS CONVECTIVE TEMPERATURES
ARE REACHED.
THE NEXT SHORTWAVE TROUGH, AND ASSOCIATED SURFACE LOW, IS
EXPECTED TO APPROACH AND CROSS THE REGION LATER FRIDAY MORNING
THROUGH FRIDAY NIGHT. MAINLY MVFR RESTRICTIONS ARE EXPECTED
MAINLY FOR AIRPORTS SOUTH OF A PHD-BVI-IDI LINE, WITH MGW AND
LBE SEEING A PERIOD OF IFR IN HEAVIER RAINFALL AND BETTER LOW
LEVEL MOISTURE. THERE COULD ALSO BE A THUNDERSTORM OR TWO AROUND
PORTIONS OF THE AREA, THOUGH THIS PROBABILITY IS TOO LOW FOR TAF
INCLUSION AT MOST OF THE AIRPORTS AT THIS TIME. THE EXCEPTION
IS MGW, WHERE A PROB30 WAS INCLUDED WITH THAT REGION SEEING
SLIGHTLY MORE FAVORABLE INSTABILITY DURING THE AFTERNOON.
OUTLOOK...
SHOWERS, POSSIBLE THUNDERSTORMS, AND RESTRICTIONS ARE EXPECTED
FRIDAY NIGHT INTO SATURDAY AS THE SHORTWAVE AND SURFACE LOW
COMPLETE THEIR PASSAGE. VFR SHOULD THEN RETURN LATE SATURDAY
THROUGH TUESDAY AS HIGH PRESSURE TRACKS ACROSS THE REGION.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...34
NEAR TERM...WM/MILCAREK
SHORT TERM...34
LONG TERM...34
AVIATION...WM
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page