375
FXUS61 KCTP 091934
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
234 PM EST TUE DEC 9 2025
SYNOPSIS
* NOT AS COLD TODAY; QUICK SHOT OF PM SNOW TODAY ACROSS THE NW
MTNS WITH LIGHT ACCUMULATION
* WINDY WITH SEVERAL INCHES OF SNOW, LOCALLY UP TO 5-6 INCHES
ACROSS NORTHERN PA WITH A SNOW/RAIN MIX ACROSS SOUTHERN PA.
* LAKE EFFECT SNOW FOLLOWS FOR THU/THU NIGHT; ADDITIONAL SNOW
ACCUMULATION POSSIBLE SAT-SUN FROM ANOTHER AREA OF LOW
PRESSURE MOVING BY JUST TO THE SOUTH AND EAST OF PA
NEAR TERM /UNTIL 6 PM THIS EVENING/
A FRIGID MORNING GRIPS THE ENTIRE REGION EARLY THIS MORNING
THANKS TO CLEAR SKIES, LIGHT/VARIABLE WIND AND DRY AIR
ASSOCIATED WITH A LARGE AREA OF SFC HIGH PRESSURE EXTENDING FROM
THE ADIRONDACK REGION OF NY TO SOUTHERN VA. TEMPS RANGED FROM
THE SINGLE DIGITS TO MID TEENS ACROSS THE SOUTH TO BETWEEN ZERO
AND 10 BELOW ACROSS THE NORTHERN MTNS OF PA. A SLIGHT WIND OF 5
KTS APPEARS TO HAVE SNAGGED A POOL OF EVEN COLDER AIR FROM THE
SE PART OF THE AIRFIELD AND DIPPED THE TEMP TO -11F THERE AT
10Z. THIS TECHNICALLY PLACES THAT LOCALIZED PART OF MCKEAN CTY
WITHIN EXTREME COLD WARNING CRITERIA, BUT THE REST OF THE COUNTY
HAS LITTLE OR NO WIND AND HIGHER TEMPS NOT EVEN IN THE COLD
WEATHER ADVISORY VALUES.
INCREASING SOUTHERLY LLVL FLOW IN THE WAKE OF THIS RIDGE WILL
TRANSPORT A LAYER OF BKN-OVC STRATOCU NNE FROM THE LAUREL
HIGHLANDS THROUGH THE CENTRAL MTNS THIS MORNING, WHILE A SHIELD
OF MID AND HIGH CLOUDS STREAMS EAST INTO THE COMMONWEALTH LATER
THIS MORNING AND THIS AFTERNOON.
A QUICK SHOT OF WEAK LOW-MID LEVEL WARM ADVECTION, COMPACT AND
TRANSIENT 850-700 FGEN AND A GLANCING BLOW BY THE NOSE
(THERMALLY INDIRECT CELL OF A 100 KT, 300 MB NWRLY JET MAX) WILL
BRING UP TO A SEVERAL HOUR PERIOD OF LIGHT SNOW ACROSS THE NW
MTNS OF PA THIS AFTERNOON AND EVENING WITH ACCUMS UP TO AROUND 1
INCH.
SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/
AN INTENSE CLIPPER LOW WILL BE RACING THROUGH THE GREAT LAKE
REGION TONIGHT INTO WEDNESDAY MORNING. WARM AIR WILL FILTER
INTO THE REGION AHEAD OF THIS ANOMALOUSLY DEEP ALBERTA CLIPPER
(ONE OF THE STRONGEST FOR THIS TIME OF YEAR BY
HISTORICAL/CLIMATOLOGICAL MSLP STANDARDS) AND IS EXPECTED TO
SPREAD ACCUMULATING LIGHT TO MODERATE SNOW ACROSS THE NW 1/2 OF
THE CWA FOR THE WEDNESDAY MORNING COMMUTE.
THUS, ANY BREAK IN THE SNOW ACROSS THE NW MTNS WILL BE VERY
SHORT- LIVED AS DUAL JET SEGMENTS (WITH THE SOUTHERN JET
STRENGTHENING TO OVER 140 KTS) ARRIVE FROM THE OHIO VALLEY ON
WEDNESDAY.
LATEST HIGH RES MODELS AND THEIR EFS (ALONG WITH A HOST OF
LARGER SCALE, OPERATIONAL MODELS) FOCUS THE PRIMARY AREA OF
UVVEL AND SNOW FROM THE NW MTNS TO SULLIVAN COUNTY IN THE NE
PART OF OUR CWA. COORDINATED WITH SURROUNDING WFO TO POST A WINT
WEATHER ADVISORY FOR ALL OF OUR NRN MTNS LATE TONIGHT EARLY
WEDNESDAY EVENING. NBM PROBS FOR 2.5 TO 3 INCHES OF SNOW - ENDING
AT 7 PM WED RANGED FROM 80-100 PCT ACROSS THE NORTHERN MTNS.
THE STRENGTH OF THE SWRLY LLVL JET (55-65 KTS) AND THE
COLLOCATION WITH THE COUPLED JET REGION AND FOCUSED DEEP-LAYER
UVVEL HAVE ALL THE MARKINGS OF A FEW TO SEVERAL HOUR PERIOD OF
MDT TO HVY (AKA THUMPING OF) SNOW LATER WED MORNING AND EARLY
AFTERNOON WITH SEVERAL OR MORE INCHES LIKELY ACROSS THE ADVISORY
AREA WITH A FEW LOCATIONS SEEING UP TO AROUND 6 INCHES. WE CAN
SEE THAT LAYER LIFTING/COOLING BY THE DECREASE IN THE MAX TW IN
THE 1000-700 MB LAYER DIP BY 1-2 DEG C DURING THE LATE MORNING
HOURS WED AS THE NOSE OF THE STRENGTHENING LLJ MOVES INTO NCENT
PA.
ACROSS THE CENTRAL AND SOUTHERN RIDGE AND VALLEY REGION OF THE
STATE AND THE LAUREL HIGHLANDS, SNOW ACCUMS SHOULD BE IN THE 1-2
INCH RANGE WITH LOCALLY AROUND 3 INCHES ON THE RIDGES NEAR THE
I-80 CORRIDOR.
ANOTHER CONCERN WOULD BE FOR A LITTLE FZRA IN THE EAST (ESP
ACROSS THE HIGHER TERRAIN OF SCHUYLKILL CTY) WED AM.
NAM IS VERY DRY FOR THE MORNING ACROSS THE SE (IN THE LOWEST
5-6 KFT AGL) WHERE TEMPS MIGHT BE ALLOWED TO WARM UP BEFORE
PRECIP HITS THE GROUND. BUT, IT IS ALSO A 3RD PERIOD FORECAST
AT THIS MOMENT. WILL ALLOW THE DAY SHIFT TO EXAMINE THE DETAILS
OF UPCOMING MODEL CYCLES TO BETTER ASSESS THE THREAT FOR LIGHT
ICING WED MORNING AND FURTHER REFINE THINGS WITH THE
NEIGHBORING OFFICES, AS IT WILL ONLY BE AN EARLY 3RD PERIOD
WORRY FOR THEM.
MODEL GUIDANCE CONTINUES TO SHOW SOME POTENTIAL FOR AN EXTENDED
WARM NOSE ACROSS THE LOWER SUSQUEHANNA VALLEY (WITH MAX TWS OF
1.5 TO 2.5C IN THE 900-800 MB LAYER BY AROUND 15Z WED) THAT
DOES INDICATE SOME FREEZING RAIN POTENTIAL AND LIGHT ICE
ACCUMULATION IF PRECIPITATION MANAGES A QUICK ENOUGH EASTWARD
EXPANSION, MAINLY IN THE 7AM-1PM TIMEFRAME. RECENT MODEL
SOUNDINGS DO OUTLINE SOME DISCREPANCIES WITH RESPECT TO HOW WARM
THE LOWER- LEVELS WILL GET AT THIS TIME, SO THERE IS QUITE A
BIT OF UNCERTAINTY WITH REGARDS TO IF ICE ACCUMULATION WILL
OCCUR, SO HAVE CONTINUED WITH NBM MODEL GUIDANCE AND WILL
HIGHLIGHT THIS POTENTIAL IN THE HWO RATHER THAN ISSUING A LOW
CONFIDENCE ADVISORY WITH SOME TIME TO IRON OUT THE FORECAST
UNCERTAINTIES IN FUTURE PACKAGES. AS THE PRECIPITATION EXPANDS
EASTWARD INTO WEDNESDAY AFTERNOON, MARGINAL TEMPERATURES/THERMAL
PROFILES WILL FAVOR A SNOW/RAIN MIX ACROSS NORTH/WESTERN
PENNSYLVANIA AS TEMPERATURES REACH INTO THE MID-30S WITH PLAIN
RAIN FROM THE CENTRAL RIDGES EASTWARD INTO THE SUSQUEHANNA
VALLEY.
AS THE STORM TRACKS THROUGH THE ST. LAWRENCE RIVER VALLEY
WEDNESDAY NIGHT THROUGH THURSDAY, COLDER NORTHWESTERLY FLOW IS
EXPECTED TO TRIGGER LAKE EFFECT SNOW WITH MINOR SNOW
ACCUMUATIONS OVER THE TYPICAL NORTHWESTERN PENNSYLVANIA SNOW
BELTS AND FAVORED UPSLOPE AREAS ALONG THE ALLEGHENY FRONT AND
LAURELS.
LONG TERM /THURSDAY THROUGH MONDAY/
LAKE EFFECT SNOW AND BREEZY NORTHWESTERLY WINDS CONTINUE ON
THURSDAY WITH ADDITIONAL SNOW ACCUMS EXPECTED OVER THE
NORTHWESTERN MOUNTAINS AND LAUREL HIGHLANDS. A COLD FRONTAL
PASSAGE EARLY THURSDAY WILL PROMOTE SOME SNOW SQUALL THREAT AS
OUTLINE IN MORE RECENT SNOW SQUALL PARAMETER GUIDANCE. THE MAIN
DETERRENT FOR SNOW SQUALLS WILL BE THAT INSTABILITY IS LARGELY
EXPECTED TO BE LIMITED GIVEN THAT THE FRONT IS PASSING ON EARLY
IN THE DAY. AT THIS TIMES, NO MENTIONS IN EVEN THE HWO GIVEN THE
LOW CONFIDENCE AT THIS JUNCTURE AND LONGER TIME HORIZON UNTIL
THE EVENT IS ON OUR DOORSTEP.
THE NEXT WINTER WEATHER SYSTEM IS PROGGED TO ARRIVE LATER
FRIDAY INTO FRIDAY NIGHT, ALTHOUGH MODELS ARE SHOWING SOME
VARIANCE WITH THE EVOLUTION AND TRACK. LAKE EFFECT SNOW/SNOW
SHOWERS CONTINUE OVER THE WEEKEND WITH TEMPERATURES STAYING
BELOW THE HISTORICAL AVERAGE HEADING INTO MID-DECEMBER.
AVIATION /19Z TUESDAY THROUGH SUNDAY/
MAINLY VFR CONDS WERE REPORTED AT 19Z TUE. AN AREA OF STRATUS
AT 3500-4500 FT CONTINUES TO PUSH ACROSS EAST-CENTRAL PA. JUST
EAST OF THE ALLEGHENY FRONT, MOST CIGS ARE UP NEAR 10,000 FEET.
WEST OF THE ALLEGHENIES, ANOTHER AREA OF STRATUS ASSOCIATED WITH
A WARM FRONT IS PUSHING EASTWARD WITH CIGS NEAR 4000-5000 FT.
THE WARM FRONT HAS ALSO PRODUCED A FEW AREAS OF LIGHT SNOW IN
WESTERN PA. VSBY REDUCTIONS DUE TO SNOW ARE POSSIBLE AT BFD
MAINLY 19Z-00Z. WINDS DURING THE DAY WILL BE OUT OF THE SOUTH AT
10 TO 15 KNOTS WITH GUSTS UP TO 20 KNOTS.
MVFR CEILINGS WILL EXPAND EAST TONIGHT, LIKELY ARRIVING AT JST,
AOO, IPT, AND UNV WITHIN A COUPLE HOURS OF SUNRISE. A CLIPPER
SYSTEM SYSTEM WILL BRING PERIODS OF LIGHT TO MODERATE SNOW TO
THE REGION ON WEDNESDAY MORNING AND INTO THE AFTERNOON,
INITIALLY MOVING INTO BFD IN THE 06-09Z TIMEFRAME. PRECIPITATION
WILL BE MUCH LIGHTER SOUTH OF UNV AND EAST OF AOO, BUT A MIX OF
RAIN, SNOW, AND FREEZING RAIN IS POSSIBLE AT MDT AND LNS DURING
THE LATE MORNING AND EARLY AFTERNOON.
LLWS WILL ALSO BECOME A FACTOR TONIGHT INTO WEDNESDAY AS A 45-60
KNOT WEST-SOUTHWESTERLY LLJ MOVES INTO WESTERN PA AFTER 00Z
WEDNESDAY. BEHIND THE COLD FRONT WED EVENING INTO THU, WINDS
WILL TURN OUT OF THE WEST AND INCREASE WITH SFC GUSTS 15-35 KTS
(HIGHEST IN THE LAURELS).
OUTLOOK...
WED NIGHT-THU...SNOW SHOWERS CONTINUE, MAINLY N/W PA. WINDY.
FRI-SUN...ADDITIONAL ROUNDS OF LIGHT SNOW POSSIBLE WITH MULTIPLE
CLIPPER SYSTEMS.
CLIMATE
BRADFORD, PA HAD TWO RECORDS IN ONE NIGHT! THEIR TEMP OF -4F
JUST BEFORE MIDNIGHT EST ON 12/8 BROKE THE PREVIOUS RECORD OF -2F
SET IN 1970. AS THE TEMP CONTINUED FALLING THROUGH THE NIGHT,
THEY TIED THE 12/9 RECORD LOW OF -12F AT 6 AM EST. THIS TIED THE
RECORD SET IN 2002.
ASTRONOMICAL WINTER (SOLSTICE) BEGINS AT 10:03 A.M. ON SUNDAY,
DECEMBER 21ST.
CTP WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 1 AM TO 10 PM EST WEDNESDAY FOR
PAZ004>006-010>012-017-018.
WINTER WEATHER ADVISORY FROM 10 AM WEDNESDAY TO 10 AM EST
THURSDAY FOR PAZ024-033.
WINTER WEATHER ADVISORY FROM 3 AM TO 10 PM EST WEDNESDAY FOR
PAZ037-041-042.
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT/DANGELO
SHORT TERM...LAMBERT/DANGELO/STEINBUGL
LONG TERM...LAMBERT/STEINBUGL
AVIATION...COLBERT/BAUCO
CLIMATE...COLBERT
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