126
FXUS61 KPBZ 061209
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
709 AM EST SAT DEC 6 2025
SYNOPSIS
PERIODIC LIGHT SNOW CHANCES AND BELOW-NORMAL TEMPERATURES
CONTINUE THROUGH THE WEEKEND. A DRY START TO NEXT WEEK TURNS
ACTIVE WITH RAIN AND SNOW CHANCES RETURNING MID TO LATE WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- LIGHT SNOW SHOWERS POSSIBLE MAINLY NORTH AND EAST OF
PITTSBURGH; LITTLE TO NO ACCUMULATIONS EXPECTED
- BELOW SEASONAL TEMPERATURES CONTINUE
---------------------------------------------------------------
A WEAK MID-LEVEL SHORTWAVE TRAVERSES THE OHIO VALLEY TODAY,
BRINGING LOW CHANCES FOR LIGHT SNOW SHOWERS TO AREAS GENERALLY
NORTH OF PITTSBURGH AND IN THE RIDGES OF SOUTHWEST PA.
OCCASIONAL FLURRIES MAY BE POSSIBLE ELSEWHERE. LITTLE TO NO
ACCUMULATIONS ARE EXPECTED AS THE NBM CONTINUES TO SUGGEST A
LESS THAN 20% CHANCE FOR EVEN A TENTH OF AN INCH OF NEW
SNOWFALL ANYWHERE IN THE LOCAL AREA.
TEMPERATURES CONTINUE TO TREND BELOW SEASONAL NORMALS, WITH
HIGHS IN THE MID 30S AND LOWS IN THE MID TO UPPER 20S.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
KEY MESSAGES:
- ANOTHER DISTURBANCE BRINGS MINOR SNOWFALL ACCUMULATIONS TO
AREAS NORTH OF PITTSBURGH AND IN THE RIDGES; A RAIN/SNOW MIX
WITH LITTLE ACCUMULATIONS EXPECTED ELSEWHERE
- DRY WEATHER AND BELOW SEASONAL TEMPERATURES PREVAIL SUNDAY
NIGHT THROUGH MONDAY NIGHT UNDER BUILDING HIGH PRESSURE
----------------------------------------------------------------
ANOTHER PASSING SHORTWAVE BRINGS HIGHER CHANCES FOR A WINTRY
MIX TO THE ENTIRE AREA ON SUNDAY. PRECIPITATION IS EXPECTED TO
START AS SNOW (POSSIBLY A RAIN/SNOW MIX IN THE MON VALLEY)
SUNDAY MORNING BEFORE TRANSITIONING TO A RAIN/SNOW MIX ACROSS
THE LOWLANDS SOUTH OF I-80 BY LATE MORNING AND AFTERNOON.
OVERALL ACCUMULATIONS WITH THE SUNDAY SYSTEM ARE STILL
ANTICIPATED TO BE LIGHT, WITH MEASURABLE SNOWFALL APPEARING MOST
LIKELY NORTH OF I-80 AND IN THE RIDGES. NBM SNOWFALL PROBABILITIES
ARE RATHER PESSIMISTIC, SUGGESTING A 40-60 PERCENT CHANCE FOR A
TENTH OF AN INCH NORTH OF PITTSBURGH AND IN THE RIDGES, BUT A
20 PERCENT CHANCE OR LESS FOR AN INCH. MEANWHILE, THE EVENT IS
JUST NOW BEGINNING TO FALL WITHIN RANGE OF THE HREF, WHICH IS
SUGGESTING HIGHER PROBABILITIES (ANYWHERE FROM 40 TO 80 PERCENT)
FOR AN INCH OF ACCUMULATION NORTH OF PITTSBURGH (AND ESPECIALLY
ALONG AND NORTH OF I-80), BUT SIGNIFICANTLY LOWER PROBABILITIES
OF AROUND 10-20% FOR 2 INCHES IN THE SAME AREAS. PROBABILITIES
ARE ALSO GENERALLY LOWER IN THE RIDGES, FOR EXAMPLE A 30 TO 50
PERCENT CHANCE FOR AN INCH OF ACCUMULATION IN THE LAURELS.
HOWEVER, THE LATEST HREF ONLY RUNS THROUGH 7PM SUNDAY, SO IT'S
POSSIBLE THESE PROBABILITIES INCREASE IN FUTURE RUNS AS SNOW
SHOWERS ARE FORECAST TO LINGER IN THE RIDGES THROUGH EVENING.
A COLD FRONT LATE SUNDAY BRINGS A REINFORCING SHOT OF COLD AIR,
LEADING TO LOW TEMPERATURES DROPPING BACK INTO THE TEENS NORTH
OF PITTSBURGH AND LOW 20S ELSEWHERE SUNDAY NIGHT. DRY WEATHER
AND BELOW-SEASONAL TEMPERATURES THEN CONTINUE MONDAY AND MONDAY
NIGHT UNDER THE INFLUENCE OF BUILDING HIGH PRESSURE.
LONG TERM /TUESDAY THROUGH FRIDAY/
KEY MESSAGES:
- BELOW NORMAL TEMPERATURES CONTINUE THROUGH THE LONG TERM.
- ADDITIONAL ROUNDS OF POTENTIAL WINTER WEATHER WITH A SERIES
OF PASSING DISTURBANCES MID AND LATE WEEK.
-------------------------------------------------------------------
ANOTHER DISTURBANCE MOVING THROUGH THE AREA TUESDAY INTO
WEDNESDAY WILL FEATURE A STRONG AND PROGRESSIVE LOW PRESSURE
SYSTEM TRACK IN FROM THE NORTHWEST AS A TROUGH OVER THE EAST
CONTINUES TO FILTER COLDER AIR AND PRECIP CHANCES INTO THE
REGION. THE SURFACE LOW ASSOCIATED WITH THIS SYSTEM IS EXPECTED
TO LIFT INTO SOUTHERN ONTARIO AS IT APPROACHES THE LOWER GREAT
LAKES, RESULTING IN WARM ADVECTION SETTING UP ACROSS THE AREA
ON WEDNESDAY WHICH WILL LIKELY FORCE A CHANGEOVER TO RAINFALL,
(THUS LIMITING SNOWFALL ACCUMULATION POTENTIAL) FOR AREAS SOUTH
OF I-80. THE LATEST NBM SHOWS A 30-50 PERCENT CHANCE FOR AN
INCH OF SNOWFALL ACCUMULATION IN THE NORTHEASTERN CORNER OF THE
CWA, GENERALLY NORTH OF I-80 AND EAST OF I-79. LOWER CHANCES
FOR AN INCH OF ACCUMULATION EXIST IN THE RIDGES, WITH A 10-30
PERCENT CHANCE FROM THE LAURELS DOWN INTO PRESTON AND TUCKER
COUNTIES IN NORTHERN WV.
THURSDAY SERVES AS A POTENTIAL TRANSITION DAY BETWEEN THE
DEPARTING MID-WEEK SYSTEM AND AN APPROACHING LATE WEEK SYSTEM,
WITH A PERIOD OF DRY WEATHER SNEAKING IN DURING THE DAY (SAVE
FOR THE RIDGES WHICH MAY SEE WEAK UPSLOPE-FORCED SHOWERS
PERSISTING). UNCERTAINTY IN TIMING OF THE DEPARTURE OF THE MID-
WEEK SYSTEM (WEDNESDAY VS. THURSDAY) AND ARRIVAL OF THE LATE
WEEK SYSTEM (THURSDAY VS. FRIDAY) IS FORCING NON-ZERO POPS IN
THE FORECAST ON THURSDAY, BUT THERE SHOULD BE AT LEAST SOME
WINDOW IN BETWEEN THE TWO SYSTEMS DURING WHICH WE SEE DRY
WEATHER AND BELOW-SEASONAL TEMPERATURES.
THE LATE WEEK SYSTEM WILL BE THE MORE INTERESTING ONE TO WATCH
AS IT DIVES SOUTHEASTWARD FROM THE CANADIAN ROCKIES INTO THE
UPPER MIDWEST HOT ON THE HEELS OF THE MID-WEEK SYSTEM AND
TRAVERSES THE OHIO VALLEY IN THE THURSDAY/FRIDAY TIMEFRAME.
THERE IS STILL A FAIR AMOUNT OF SPREAD REGARDING THE TRACK AND
POTENCY OF THIS DISTURBANCE, BUT THERE ARE SOME GLOBAL MODELS
AND ENSEMBLE MEMBERS THAT DEPICT A SCENARIO IN WHICH THE LOW
MOVES EITHER THROUGH OR SOUTH OF THE LOCAL AREA, WHICH WOULD
INCREASE OUR CHANCES IN SEEING IMPACTFUL WINTER WEATHER. THIS
WILL BE A SYSTEM TO KEEP AN EYE ON AS WE HEAD INTO NEXT WEEK.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
A LOW MVFR DECK OF STRATUS STILL SITS ACROSS THE REGION THIS
MORNING. VFR CIGS ARE OBSERVED ON THE W/NW SIDE OF THIS DECK,
AND EVENTUAL EROSION/EASTWARD MOVEMENT OF THIS IS EXPECTED TO
SLOWLY BRING VFR BACK TO MOST AREA PORTS THROUGH THE MORNING
HOURS. IT'S TOUGH TO PINPOINT THE BACK EDGE OF IT ON SATELLITE
WITH UPPER LEVEL CLOUDS OBSTRUCTING, BUT OBSERVATIONS SUGGEST
IT'S ALONG A LINE ROUGHLY FROM ZZV TO BVI AS OF 12Z.
EROSION OF THE STRATUS DECK COMBINED WITH INCREASED MIXING/LIFT
THIS MORNING AHEAD OF AN INCOMING SHORTWAVE SHOULD RESULT IN
IMPROVEMENTS. HOWEVER, ANY VFR CONDITIONS ARE LIKELY TO BE
SHORT-LIVED AS THE AFTERNOON PASSAGE OF THE SHORTWAVE RE-
INTRODUCES AN MVFR STRATOCU DECK AND LOWER PROBABILITY LIGHT
SNOW SHOWERS (FKL/DUJ HAVING GREATEST LIKELIHOOD FOR VISIBILITY
IMPACTS DUE TO SNOW, SO HAVE INTRODUCED A TEMPO GROUP FOR
-SHSN THERE).
OUTLOOK...
THE OVERALL WEATHER PATTERN THROUGH LATE NEXT WEEK STRONGLY
FAVORS SHORTWAVE MOVEMENT WITHIN UPPER TROUGHING THAT OCCURS
ALMOST EVERY OTHER DAY. EACH SYSTEM WILL FEATURE VARYING DEGREES
OF PRECIPITATION CHANCES (TYPE MAINLY SNOW, SAVE FOR SHORT
PERIODS OF RAIN AT SOUTHERN TERMINALS), INTENSITIES, AND EITHER
THE CONTINUATION OF OR REINTRODUCTION TO MVFR-IFR RESTRICTIONS.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...SHALLENBERGER
NEAR TERM...CERMAK
SHORT TERM...CERMAK
LONG TERM...CERMAK
AVIATION...MLB/AK
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