007
FXUS61 KPBZ 170655
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
155 AM EST WED DEC 17 2025
SYNOPSIS
DRY WEATHER CONTINUES WITH HIGH PRESSURE IN BEFORE RAIN RETURNS
LATER TODAY WITH A CROSSING COLD FRONT, CHANGING OVER TO SNOW
ON FRIDAY. DRY WEATHER RETURNS SATURDAY.
NEAR TERM /THROUGH TODAY/
KEY MESSAGES:
- DRY WEATHER CONTINUES
-----------------------------------------------------------
DRY WEATHER CONTINUES EARLY THIS MORNING AS HIGH PRESSURE
TRANSITIONS ACROSS THE REGION. LOW-LEVEL STRATUS HAS OVERSPREAD
MUCH OF THE REGION WHICH WILL KEEP TEMPERATURES FROM DROPPING
DOWN TO LOWS OBSERVED THE PAST DAY. LATEST OBSERVATIONS AS OF
BETWEEN 1 AM AND 2 PM HAVE SHOWN TEMPERATURES FLATLINED, OR
INCREASING AT SOME LOCATIONS WITH INCREASED WARM ADVECTION.
MORE WIDESPREAD HOURLY TEMPERATURE RISES ARE EXPECTED BEFORE
SUNRISE AHEAD OF AN APPROACHING FRONT.
A WEAK SHORTWAVE AND THE MENTIONED MOISTURE-STARVED SURFACE
FRONT WILL CROSS THE REGION TODAY, BUT THE MAIN IMPACT WILL
JUST BE INCREASED/PERSISTENT CLOUD COVERAGE WITH MINIMAL UPPER
SUPPORT OR MOISTURE. WINDS WILL BECOME MORE GUSTY ACROSS THE
REGION WITH AN INCREASED PRESSURE GRADIENT. THE HIGHER TERRAIN
OF WV COULD POSSIBLY SEE BUSTY FROM 40-45 MPH TODAY.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/
KEY MESSAGES:
- RAIN RETURNS WITH A COLD FRONT LATE THURSDAY AND THURSDAY
NIGHT
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A SHORTWAVE TROUGH AND ASSOCIATED SURFACE COLD FRONT IS
EXPECTED TO ADVANCE EASTWARD OUT OF THE CENTRAL CONUS ON
THURSDAY. WARM ADVECTION IN SOUTHWEST FLOW AHEAD OF THIS SYSTEM
SHOULD RESULT IN HIGH TEMPERATURES AROUND 10 DEGREES ABOVE
AVERAGE FOR THIS TIME OF THE YEAR.
RAIN CHANCES WILL BEGIN TO INCREASE LATER THURSDAY AS THE
SHORTWAVE APPROACHES, THOUGH MOST OF THE PRECIP SHOULD ARRIVE BY
EVENING. LIMITED JET SUPPORT SHOULD ALSO ENHANCE ASCENT AS THE
SURFACE COLD FRONT CROSSES THE REGION OVERNIGHT. SOME SNOW COULD
MIX WITH THE RAIN IN COLD ADVECTION BEFORE INITIALLY TAPERING
OFF AFTER FROPA LATE THURSDAY NIGHT, THOUGH NO SIGNIFICANT
ACCUMULATION IS EXPECTED.
CURRENT QPF PROGS RANGE FROM 0.5 TO 0.75. WITH THE CURRENT
SNOWPACK WATER EQUIVALENT RANGING FROM 0.25 TO 0.4 INCHES, NO
HYDRO CONCERNS ARE ANTICIPATED AT THIS TIME.
LONG TERM /FRIDAY THROUGH TUESDAY/
KEY MESSAGES:
- WIDESPREAD RAIN CHANCES RETURN
- QUICK COLD-SHOT ON FRIDAY
- DRY WEATHER ON SATURDAY
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THE LONG TERM PERIOD BEGIN ON FRIDAY WITH THE PASSAGE OF A
STRONG COLD FRONT. THE NORTHWEST FLOW SETTING UP AND COLDER AIR
MOVING INTO BEHIND THE FRONT WILL ALLOW THE LAKE EFFECT SNOW
THREAT TO ENGAGE. THIS WILL KEEP SNOW SHOWERS IN THE FORECAST
FOR FRIDAY. SNOW ACCUMULATION POTENTIAL SHOULD REMAIN NORTH OF
THE FORECAST AREA AS NBM PROBS FOR JUST 1 INCH OF SNOW IS ONLY A
40% POTENTIAL.
BY THE SATURDAY TIME FRAME, WE GET A REPRIEVE WITH A BRIEF
BREAK IN BETWEEN SHORTWAVES. BY SUNDAY, MONDAY, AND TUESDAY THE
PATTERN WILL REMAIN IN NORTHWEST FLOW WITH A PROLONGER PERIOD OF
LAKE EFFECT POTENTIAL AND MINOR SHORTWAVES CROSSING TO THE NORTH
OF THE FORECAST AREA. THIS WILL BE A PERIOD WHERE HIGH PRESSURE
WILL BE THE MAIN INFLUENCE BUT THE LAKE EFFECT PROCESS WILL BE
IN EFFECT. A SYNOPTIC SYSTEM MAY IMPACT THE AREA TOWARDS THE END
OF THE FORECAST PERIOD AS THE PATTERN TAKES AN
ACTIVE/PROGRESSIVE APPROACH.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
KEY MESSAGES:
- MVFR DECK TRAVERSING AREA THROUGH 12Z
- SW WIND GUSTS BETWEEN 15-25KTS DURING DAYLIGHT HOURS
- UNCERTAINTY ON NORTHERN FRONT TIMING AND ITS SOUTHWARD SPREAD
OF MVFR RESTRICTIONS
------------------------------------------------------------
WARM ADVECTION WITHIN SOUTHWEST FLOW AHEAD OF A NORTHERN STREAM
SHORTWAVE WILL PULL A MVFR TO VFR STRATUS LAYER OVER THE REGION
THROUGH 12Z BEFORE DRY ADVECTION/SUBSIDENCE BEHIND IT RESULTS IN
CLEARING OF THIS DECK. CONFIDENCE IS FAIRLY HIGH IN TIMING THE
TRANSITION TO HIGHER MVFR CIG THEN VFR CIG BEFORE CLEARING AIDED
BY RECENT OBSERVED METAR TRENDS SOUTHWEST OF THE AREA.
A TIGHTENED SURFACE GRADIENT PLUS DEEPER MIXING LENDS TO 15-25KT
SOUTHWEST WIND GUSTS BETWEEN 12Z-21Z THAT WILL QUICKLY CALM
AND BEGIN VEERING EASTERLY DUE TO A COMBINATION OF LOSS OF
DIURNAL MIXING AND APPROACH OF A STALLING SURFACE BOUNDARY.
THIS FRONTAL BOUNDARY WILL ENCROACH NORTHWEST PA AROUND 18Z
BEFORE EXHIBITING A TRANSITION TO STALLED BOUNDARY AS ITS UPPER
SHORTWAVE RACES TOWARD NEW ENGLAND. UNCERTAINTY REMAINS IN ITS
SOUTHWARD REACH PRIOR TO STALLING (I-80 CORRIDOR STALL VERSUS
I-70 CORRIDOR STALL) AS WELL AS THE EXTENT/HEIGHT OF THE COLD
ADVECTION STRATOCU SHIELD BEHIND/NORTH OF IT. GUIDANCE CURRENTLY
FAVORS MVFR BEHIND THE BOUNDARY WITH IT STALLING NEAR KPIT, SO
TAFS REFLECT THIS SCENARIO.
OUTLOOK...
TRANSITION BACK TO SOUTHWESTERLY FLOW ALOFT WILL QUICKLY LIFT
THE STALLED BOUNDARY NORTHWARD THROUGH THURSDAY MORNING AS VFR
CONDITIONS WITH BREEZY WIND RETURNS. PASSAGE OF A LOW PRESSURE
SYSTEM LATER THAT DAY MEANS WIDESPREAD RAIN WITH MVFR/IFR
RESTRICTIONS THAT SEE A BRIEF PERIOD OF SNOW AMID COLD ADVECTION
PRIOR TO ITS EXIT FRIDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...88
NEAR TERM...88
SHORT TERM...88
LONG TERM...SHALLENBERGER/88
AVIATION...FRAZIER
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