545
FXUS61 KPBZ 170948
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
448 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 /UNTIL 6 PM THIS EVENING/
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 SHOW
TEMPERATURES HAVE PRETTY MUCH FLATLINED, OR HAVE INCREASED 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 GUSTY WINDS BETWEEN 40-45 MPH TODAY.
SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/
KEY MESSAGES:
- RAIN RETURNS THURSDAY AND THURSDAY NIGHT
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A SHORTWAVE TROUGH AND ASSOCIATED SURFACE COLD FRONT APPROACHING
FROM THE EAST WILL RESULT IN INCREASED WARM ADVECTION AND RESULT
IN TEMPERATURES AROUND 10 DEGREES ABOVE AVERAGE FOR THIS TIME
OF THE YEAR.
RAIN CHANCES WILL BEGIN TO INCREASE LATER OVER THE COURSE OF THE
DAY AS THE SHORTWAVE APPROACHES, THOUGH MOST OF THE
PRECIPITATION SHOULD HOLD OFF UNTIL THE EVENING. SNOW WILL
EVENTUALLY MIX WITH THE RAIN IN COLD ADVECTION BEFORE TAPERING
OFF AFTER FROPA LATE THURSDAY NIGHT. NO SIGNIFICANT ACCUMULATION
IS EXPECTED.
LONG TERM /FRIDAY THROUGH TUESDAY/
KEY MESSAGES:
- WIDESPREAD RAIN AND COLDER ON FRIDAY
- DRY WEATHER RETURNS ON SATURDAY
-------------------------------------------------------------------
NORTHWESTERLY FLOW ON THE HEELS OF THE MENTIONED FRONT WILL
KEEP LAKE ENHANCED SNOW IN PLAY 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 SATURDAY WE GET A REPRIEVE WITH A BRIEF BREAK IN BETWEEN
SHORTWAVES. SUNDAY, MONDAY, AND TUESDAY THE PATTERN WILL REMAIN
IN NORTHWEST FLOW WITH A PROLONGED 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 /09Z 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...88
AVIATION...FRAZIER
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