587
FXUS61 KPBZ 091123
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
723 AM EDT WED JUL 9 2025
SYNOPSIS
A SURFACE FRONT WILL MEANDER ACROSS THE REGION THROUGH THE WEEK
AND INTO THE WEEKEND MAINTAINING DAILY SHOWER AND THUNDERSTORM
CHANCES.
NEAR TERM /UNTIL 6 PM THIS EVENING/
KEY MESSAGES:
- STALLED BOUNDARY ALONG THE PA/WV BORDER KEEPS MOST CONVECTION
SOUTH OF PITTSBURGH TODAY.
- DAYTIME HIGHS TOP OUT JUST ABOVE NORMAL.
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LIGHT RADAR RETURNS MOVE ACROSS THE AREA THIS MORNING WITH A
WEAK- MID LEVEL WAVE, BUT DRY SUB-CLOUD LAYER AIR IS PREVENTING
MUCH OF THIS FROM REACHING THE GROUND. HAVE SEEN A FEW REPORTS
OF LIGHT SHOWERS, BUT OVERALL THIS ACTIVITY WILL BE UNIMPACTFUL
THIS MORNING.
LATEST SURFACE ANALYSIS SHOWS A PSEUDO-STATIONARY BOUNDARY
PARKED ALONG THE PA/WV BORDER, WHICH WILL SERVE AS THE FOCAL
POINT FOR ANY CONVECTIVE DEVELOPMENT TODAY ONCE INSTABILITY
INCREASES WITH DIURNAL HEATING. INCREASED MID AND UPPER LEVEL
CLOUD COVERAGE WILL PERSIST THROUGH THE PERIOD WITH INCREASED
MOISTURE ADVECTION AHEAD OF AN APPROACHING MID-LEVEL SHORTWAVE.
THE CLOUD COVERAGE THAT HAS INCREASED OVER THE COURSE OF THE
NIGHT HAS MITIGATED ANY WIDESPREAD FOG DEVELOPMENT THIS MORNING,
AND DO NOT ANTICIPATE THE NEED FOR ANY ADVISORIES AT THIS TIME.
MODELS, ANALOGS, AND MACHINE LEARNING GUIDANCE ARE ALL IN
AGREEMENT WITH MINIMAL STRONG/SEVERE POTENTIAL WITH ANY
CONVECTION TODAY. THIS WOULD BE LIMITED TO PORTIONS OF NORTHERN
WEST VIRGINIA, WHERE THERE IS BETTER INSTABILITY/STRONGER
UPDRAFT POTENTIAL, AND POTENTIAL FOR LOCALIZED HEAVY RAINFALL,
BUT THE OVERALL THREAT IS LOW.
SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/
KEY MESSAGES:
- BETTER COVERAGE OF SCATTERED STORMS THURSDAY AS BOUNDARY LIFTS
BACK NORTH.
- SLIGHTLY ABOVE NORMAL TEMPERATURES CONTINUE.
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CONVECTION FADES THIS EVENING, WITH THE OVERNIGHT PERIOD LARGELY
DRY ACROSS THE REGION. ON THURSDAY, A CROSSING SHORTWAVE TROUGH
WILL PUSH THE AFOREMENTIONED BOUNDARY NORTH AGAIN AS A WARM
FRONT, RESULTING IN SLIGHTLY MORE DIURNAL CONVECTIVE COVERAGE.
RELATIVELY WEAK CAPE PROFILES AND RELATIVELY LOW SHEAR SUGGEST A
MINIMAL SEVERE THREAT. LATEST MSU-CLP AND CIPS GUIDANCE DOES NOT
HINT AT MUCH POTENTIAL AT ALL FOR SEVERE CONVECTION OR FLOODING
IN THE PERIOD.
LONG TERM /FRIDAY THROUGH TUESDAY/
KEY MESSAGES:
- STALLED BOUNDARY LINGERS INTO THE WEEKEND AT LEAST WITH
CONTINUED DAILY RAIN CHANCES, CURRENTLY HIGHEST SUNDAY.
- LOW RAIN CHANCES NEXT WEEK AS PATTERN UNCERTAINTY INCREASES.
- CONTINUED NEAR TO ABOVE-NORMAL TEMPERATURE.
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ON FRIDAY, A WAVE OF LOW PRESSURE ALONG THE BOUNDARY MAY PUSH IT
FURTHER SOUTH, KEEPING HIGHER DIURNAL SHOWER/STORM CHANCES
ACROSS OUR SOUTHERN ZONES. PRECIPITABLE WATER REMAINS ELEVATED
NEAR AND SOUTH OF THE BOUNDARY, SO LOCALLY HEAVY RAINFALL WILL
REMAIN POSSIBLE.
MAINLY DIURNAL SHOWER AND STORM CHANCES CONTINUE INTO THE
WEEKEND, WITH THE BEST CHANCE FOR MORE WIDESPREAD COVERAGE ON
SUNDAY AS SURFACE LOW PRESSURE TRANSITIONS OVER THE NORTHERN
GREAT LAKES AND THE ASSOCIATED COLD FRONT CROSSES THE REGION.
THERE IS SOME UNCERTAINTY IN TIMING OF FROPA, SO WITH THAT, NBM
10TH TO 90TH PERCENTILE SPREADS CONTINUE TO EXCEED 10 DEGREES
FOR MOST OF THE REGION, WITH POSSIBLE MAX VALUES RANGING FROM
AROUND 80 TO THE LOWER 90S. SEVERE/FLOODING POTENTIAL IS NON-
ZERO, BUT ON THE LOW END AT THIS TIME BASED OFF LATEST MODELS,
ANALOGS, AND MACHINE LEARNING GUIDANCE.
UNCERTAINTY THEM PROPAGATES INTO NEXT WEEK. ELEVATED 500MB HEIGHTS
AND ZONAL FLOW ALOFT ARE MOST LIKELY, KEEPING TEMPERATURES NEAR TO
ABOVE NORMAL, BUT DIFFERENCES IN DISTURBANCES IN THAT FLOW
REQUIRE LOW-END POPS FOR BOTH MONDAY AND TUESDAY.
AVIATION /11Z WEDNESDAY THROUGH SUNDAY/
SOME AREAS OF FOG THIS MORNING ARE BRINGING REDUCED VISIBILITY
TO PRIMARILY MVFR AT LBE AND FKL WHILE ALL OTHER TERMINALS
REMAIN VFR. EXPECT THAT THIS WILL BE THE CASE THROUGH THE
MORNING HOURS WHEN DIURNAL HEATING WILL ERODE ANY FOG/LOW
STRATUS BY 13Z WITH VFR THEN EXPECTED THE REST OF THE DAY.
SHORTWAVE MOVEMENT IS LIKELY TO BE DISPLACED TOO FAR NORTH/SOUTH
TO GENERATE PRECIPITATION, HOWEVER, THERE IS A LOW PROBABILITY
(30%) FOR A SHOWER BETWEEN 18Z-00Z AT ZZV AND MGW. HAVE INCLUDED
A PROB30 FOR THIS AT BOTH SITES. ELSEWHERE, EXPECT A MID-LEVEL
CLOUD DECK IN PLACE WITH A LIGHT SOUTHWESTERLY WIND. FOLLOWING
SUNSET, THE PROBABILITY FOR A RAIN SHOWER DECREASES.
SOME FOG DEVELOPMENT IS AGAIN POSSIBLE TONIGHT WITH LIGHT TO
CALM WIND AND ELEVATED SURFACE MOISTURE. HI RES PROBABILITY
FAVORS SIMILAR DEVELOPMENT TO TUESDAY NIGHT WITH PERSISTENCE IN
A RELATIVELY UNCHANGED AIRMASS BRINGING ELEVATED CHANCES FOR
MGW, LBE, AND DUJ.
OUTLOOK...
A WEAKLY FORCED BUT WARM/HUMID ENVIRONMENT IS FAVORED THROUGH
THE END OF THE WEEK THAT WILL ALLOW FOR INTERMITTENT PERIODS OF
SHOWERS/THUNDERSTORMS; CONFIDENCE IS LIKELY TO BE LOWER ON
TIMING VARIOUS ROUNDS OF PRECIPITATION AS WELL AS THE RESULTANT
CIG/VIS IMPACT THEY COULD HAVE DURING THE MORNING HOURS.
MORE SIGNIFICANT UPPER LEVEL AND SURFACE BOUNDARY MOVEMENT APPEARS
TO ARRIVE OVER THE WEEKEND THAT WILL CREATE A MORE FOCUSED AND
BETTER TIMED PERIOD FOR CONVECTION AND RESTRICTION DEVELOPMENT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...88
NEAR TERM...MLB/88
SHORT TERM...88
LONG TERM...88
AVIATION...MLB
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