337
FXUS61 KCTP 121801
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
101 PM EST FRI DEC 12 2025
SYNOPSIS
* FAIR, GENERALLY DRY WEATHER IS EXPECTED TODAY WITH MUCH LOWER
WIND GUSTS
* A PERIOD OF ACCUMULATING SNOW POSSIBLE SATURDAY AFTERNOON
INTO EARLY SUNDAY, FOLLOWED BY ANOTHER ARCTIC BLAST AND
LOCALLY HEAVY LAKE EFFECT SNOW ACROSS NW PA
* WINDY SUNDAY INTO MONDAY
* SIGNS OF A WARMER PATTERN CHANGE ON THE HORIZON BY THE MIDDLE
OF NEXT WEEK
NEAR TERM /UNTIL 7 PM THIS EVENING/
MID MORNING UPDATE.
A FEW SMALL BANDS OF FLURRIES AND VERY LIGHT SNOW SHOWERS JUST
TO THE SOUTH OF THE OFFICE, BUT OVERALL NOT MUCH GOING ON NOW,
AFTER SEVERAL SQUALL WARNINGS LAST EVENING. WINDS NOT BAD
EITHER, AFTER THE EVENTS OF LAST FEW WEEKS.
EARLIER DISCUSSION BELOW.
LAKE EFFECT/UPSLOPE CLOUDS AND SCATTERED LIGHT SNOW SHOWERS WILL
CONTINUE FOR MUCH OF THIS MORNING AS NW LLVL FLOW CONTINUES WITH
THE FLAT 850 MB RIDGE STILL WAY OFF TO OUR WEST. THE BASE OF THE
SUBSIDENCE INVERSION FALL TO 3 KFT AGL OR LESS TODAY, BUT THE
TOP OF THE SHALLOW STRATOCU CLOUDS WILL STILL BE COLD ENOUGH AND
RESIDE WITHIN THE FAVORABLE DGZ. ANY ADDITIONAL ACCUMULATION
WILL LIKELY BE 1/2 INCH OR LESS.
OTHERWISE, MORNING SUNSHINE WILL MIX WITH CLOUDS AND CREATE A
LIGHT TO MODERATE WEST TO NW BREEZE TODAY (BUT MUCH LESS GUSTY
THAN YESTERDAY).
HIGH TEMPS TODAY WILL BE ABOUT 3 DEG F HIGHER THAN THURSDAY, BUT
THE MUCH LOWER WIND WILL MAKE IT FEEL NOTABLE WARMER.
SHORT TERM /7 PM THIS EVENING THROUGH SUNDAY NIGHT/
AN APPROACHING SURFACE LOW PRESSURE TRACKING ACROSS THE UPPER
GREAT LAKES WILL BRING THICKENING LAYERED CLOUDS TONIGHT WITH
INCREASED CHANCES OF LIGHT WAA SNOW (LESS THAN 1" OF
ACCUMULATION) DOWNWIND OF LAKE ERIE INTO NORTHWESTERN
PENNSYLVANIA LATE TONIGHT INTO EARLY SATURDAY.
UPSLOPE FLOW WILL LIKELY LEAD TO A SLIGHTLY EARLIER ARRIVAL
TIME COMPARED TO RECENT MODEL GUIDANCE, THUS HAVE MENTIONS
BEGINNING SLIGHTLY AFTER MIDNIGHT TONIGHT.
TO THE SOUTH OF THE MAIN UPPER LOW CENTER NEAR LAKE SUPERIOR,
ANOTHER FAST MOVING SYSTEM WILL STREAK AROUND THE SOUTHERN
PERIPHERY OF THE UPPER TROUGH FROM THE NORTHERN PLAINS THROUGH
THE OHIO VALLEY AND INTO THE CENTRAL APPALACHIANS AND MID
ATLANTIC SATURDAY NIGHT THROUGH SUNDAY MORNING. THE UPPER TROUGH
IS FCST TO DIG/AMPLIFY AS IT PIVOTS EASTWARD AND SHOULD DRIVE
COASTAL LOW DEVELOPMENT WHILE DRAGGING A POCKET OF -20C AIR AT
850MB INTO SOUTHWEST PA/WV BY SUNDAY AFTERNOON.
ODDS ARE RISING FOR A BROAD AREA OF EXPANDING/ACCUMULATING SNOW
SATURDAY NIGHT THROUGH EARLY SUNDAY ACROSS CPA. NBM PROBS FOR
>3" ARE HIGHEST OVER THE SOUTHERN LAURELS AND SOUTHEAST PORTION
OF THE LOWER SUSQUEHANNA VALLEY. THE ARRIVAL OF ARCTIC AIR
ENSURES SNOW CHARACTER WILL BE VERY DRY AND FLUFFY.
AS THIS COLDER AIR POURS OVER THE RELATIVELY WARMER (MID TO
UPPER 30S F) WATER OF LAKE ERIE, ANOTHER BOUT OF SIGNIFICANT
LAKE EFFECT SNOW WILL DEVELOP FOR OUR NW MTNS - WITH THE
HEAVIEST AMOUNTS FOCUSED ACROSS WARREN AND MCKEAN COUNTY AND
DESERVING OF A WINT STORM WATCH FOR LAKE EFFECT SNOW FOR THOSE
2 COUNTIES.
MAX TEMPS SUNDAY WILL DROP BY 10-20 DEGREES VS. SATURDAY WITH
MEAN DEPARTURES FROM CLIMO ON THE ORDER OF 15 TO 25 DEGREES. A
FEW LOCATIONS COULD SEE HIGHS CLOSE TO THE DAILY RECORD LOW MAX.
GUSTY WINDS AND VERY COLD TEMPS WILL SEND MIN WIND CHILLS NEAR
AND BELOW ZERO SATURDAY NIGHT THROUGH SUNDAY NIGHT/AM MONDAY.
LAKE EFFECT/UPSLOPE SNOW SHOWERS CONTINUE THROUGH SUNDAY NIGHT.
LONG TERM /MONDAY THROUGH FRIDAY/
WINDS BY TUESDAY SHIFT MORE TO THE WEST, THEN TO THE SOUTHWEST
BY WEDNESDAY, AS A LARGE HIGH PRESSURE SYSTEM MOVES EASTWARD
TO THE SOUTHEAST STATES. THE LARGE SCALE FLOW PATTERN BECOMES
MORE ZONAL, AS UPPER LEVEL HEIGHTS RISE TO MUCH HIGHER VALUES
THAN WE HAD SEEN LATELY. THIS WILL SET THE STAGE FOR TEMPERATURES
CLIMBING TO ABOVE NORMAL, AT LEAST FOR THE PERIOD WEDNESDAY
INTO FRIDAY. A COLD FRONT LATER FRIDAY WILL EDGE THINGS BACK
DOWN SOME, BUT NOT THE REALLY COLD THAT HAS BEEN TYPICAL THIS
MONTH SO FAR. THE MONTH HAS BEEN NEARLY 10 DEGREES COLDER THAN
NORMAL UP TO THIS POINT, WHICH IS NEARLY HALF OF DECEMBER.
EARLIER DISCUSSION BELOW.
ONE MORE SHORTWAVE TROUGH COULD BRUSH THE AREA WITH LIGHT SNOW
EARLY NEXT WEEK; OTHERWISE THERE IS GROWING CONFIDENCE IN A MID
TO LATE DECEMBER THAW AS THE PATTERN TRANSITIONS TO A MILDER SW
FLOW ALOFT WITH MEAN TROUGHING SHIFTED WESTWARD INTO THE CENTRAL
U.S. DRY WX IS FAVORED TUE-THU WITH HIGHS CLIMBING TOWARD THE
40-50F RANGE LATE IN THE WEEK - POSSIBLY IN ADVANCE OF THE NEXT
WIDESPREAD PRECIP EVENT.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
MVFR CLOUDS RE-ESTABLISHED OVER WRN AND CENT MTNS, BUT HAVE
BEGUN TO RECEDE FROM THE EAST IN PAST 2HRS. WIND SHOULD BE
GETTING LIGHTER THROUGH THE AFTN AND EVENING, AND NEARLY CALM
OVERNIGHT. WIND WILL INCREASE SLIGHTLY ON SAT. CLOUDS WILL
THICKEN UP FROM THE WEST EARLY IN THE AM, WITH LIGHT TO MDT
SNOW HITTING THE GROUND IN THE WESTERN HIGHLANDS (ESP JST)
BEFORE NOON LOCAL/17Z. L/IFR IN SN WILL SPREAD EAST AND AFFECT
ALL OF THE AREA SAT AFTN AND NIGHT, BUT END IN IPT/AOO/UNV FIRST
(BY MIDNIGHT LOCAL (05Z). JST WILL BE LIFR FOR A 3-6HR PERIOD AS
THEY SHOULD HAVE THE STEADIEST SNOW OF ANY OF OUR TERMINALS FOR
THE LONGEST TIME SAT AFTN/EVENING. IFR MAY (50%) LINGER CLOSER
TO SUNRISE IN THE SE (MDT/LNS) WITH THE WORST CONDITIONS THERE
BETWEEN 04Z-09Z. LNS WILL LIKELY BE WORSE THAN MDT WITH THE
HEAVIEST SNOW FALLING TO OUR SE (PHILLY/DC). IT WILL GET WINDY
ON SUN AND INTO EARLY SUN NIGHT AS VERY COLD AIR MOVES IN. THE
WESTERN TERMINALS (BFD AND JST MAY (40%) HAVE A FEW HOUR BREAK
SUN AM BEFORE LAKE EFFECT KICKS BACK IN, AND CIGS/VSBYS DROP
AGAIN SUN LATE AM/AFTN.
OUTLOOK...
SUN...SHSN/IFC LINGER IN WESTERN HIGHLANDS. MVFR CIGS/ISOLD
SHSN AOO/UNV. MVFR/VFR CIGS ELSEWHERE. GUSTY WEST WIND.
MON...MVFR W/SCT SHSN BFD, NO SIG WX ELSEWHERE.
TUE-WED...NO SIG WX.
CLIMATE
ASTRONOMICAL WINTER (SOLSTICE) BEGINS AT 10:03 A.M. ON SUNDAY,
DECEMBER 21ST.
CTP WATCHES/WARNINGS/ADVISORIES
LAKE EFFECT SNOW WARNING FROM 10 AM SATURDAY TO 7 AM EST
MONDAY FOR PAZ004-005.
WINTER WEATHER ADVISORY FROM 10 AM SATURDAY TO 7 AM EST MONDAY
FOR PAZ010-017-024-033.
SYNOPSIS...LAMBERT/STEINBUGL/MARTIN
NEAR TERM...LAMBERT/MARTIN/NPB
SHORT TERM...LAMBERT/STEINBUGL/NPB
LONG TERM...STEINBUGL/MARTIN/NPB
AVIATION...DANGELO
CLIMATE...STEINBUGL
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