958
FXUS61 KCTP 091809
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
109 PM EST FRI JAN 9 2026
WHAT HAS CHANGED
MAX TEMPERATURES ON SATURDAY HAVE BEEN CUT DOWN BY ~10 DEGREES
THANKS TO AN EMERGING COLD AIR DAMMING PATTERN; THE SENSIBLE
WEATHER RESULT WILL BE A RATHER UNPLEASANT/CHILLY AND WET START
TO THE WEEKEND.
KEY MESSAGES
1) MILD TODAY WITH PERIODS OF RAIN SPREADING FROM WEST TO EAST;
TAPERING OFF LATE. MUCH COOLER START TO THE WEEKEND THAN
PREVIOUSLY FORECAST.
2) TRENDING COLDER SATURDAY NIGHT AND BECOMING WINDY ON SUNDAY
WITH MAX GUSTS 35-45 MPH PUSHING ADVISORY LEVEL THRESHOLDS
3) MINOR SNOW ACCUMULATION IN THE NW ALLEGHENIES AND LAUREL
HIGHLANDS COULD IMPACT TRAVEL SUNDAY INTO SUNDAY NIGHT. A FEW
LOCALIZED HEAVY SNOW SHOWERS/SQUALLS ARE ALSO POSSIBLE OVER THE
WESTERN HALF OF PA.
DISCUSSION
KEY MESSAGE 1...
VERY MILD START THIS MORNING WITH SUNRISE/DAYBREAK TEMPS ABOVE
THE AVERAGE MAX TEMPERATURE FOR THIS TIME OF YEAR IN MOST
LOCATIONS (ESPECIALLY THE WESTERN HALF OF CPA). PERIODS OF RAIN
GRADUALLY SPREAD FROM WEST TO EAST TODAY IN ADVANCE OF A COLD
FRONT OR ALONG A HIGH PWAT/LLJ AXIS LATER THIS MORNING THROUGH
THE EVENING BEFORE TAPERING OFF OVERNIGHT. RAINFALL TOTALS
SHOULD AVERAGE BETWEEN 0.10-0.25" THROUGH 7PM. THE FRONT SHIFTS
TO THE SOUTH AND EAST LATE TONIGHT ALLOWING HIGH PRESSURE TO
MIGRATE INTO THE AREA. THIS WILL PROVIDE A LULL/BREAK IN RAIN
INTO SATURDAY MORNING WHILE SETTING UP A COLD AIR DAMMING WEDGE
PATTERN. HIRES MODELS SHOW OVERRUNNING PRECIP RETURNING
NORTHWARD BY SATURDAY AFTERNOON WHICH WILL RESULT IN A RATHER
UNPLEASANT/CHILLY/DANK START TO THE WEEKEND. NAM/HREF MAY BE TOO
COLD? IN THIS SCENARIO DEPICTING FREEZING RAIN OVER THE
NORTHERN RIDGETOPS. RAIN TOTALS ON SATURDAY ARE EXPECTED TO BE
HIGHER THAN TODAY (FRIDAY) WITH WIDESPREAD QPF AMOUNTS IN THE
0.25-0.50 INCH RANGE. THE EXPECTED RAINFALL COMBINED WITH
SNOWMELT FROM THE ONGOING/EARLY JANUARY THAW WILL CAUSE RISES ON
RIVERS AND STREAMS; WE WILL CONTINUE TO MONITOR FOR ICE JAMS.
KEY MESSAGE 2...
WINDS INCREASE ON SUNDAY WITH STRONG LLVL CAA/STEEPENING LAPSE
RATES PROMOTING DEEP BL MIXING WITH MAX GUSTS LIKELY REACHING
INTO THE 35-45 MPH RANGE. HIGHER GUSTS >45 MPH ARE POSSIBLE AND
A WIND ADVISORY MAY BE NEEDED. TEMPERATURES WILL DROP BELOW THE
FREEZING MARK OVER THE NW 1/2 OF THE CWA BY 7AM SUNDAY BEHIND
THE OCCLUDED FRONT.
KEY MESSAGE 3...
SECONDARY COLD FRONT WILL DELIVER A COLDER/MORE SEASONAL WNW
FLOW REGIME THAT WILL DRIVE LAKE EFFECT AND UPSLOPE SNOW
SHOWERS DOWNWIND OF LAKE ERIE OVER THE ALLEGHENY PLATEAU SUNDAY
INTO SUNDAY NIGHT. MINOR ACCUMULATIONS ARE FORECAST FROM
0.5-2.0" IN THE FAVORED NW SNOWBELTS AND LAUREL RIDGETOPS.
GFS/NAM FCST SNSQ PARAMETER INDICATES A FEW HEAVIER SNOW SHOWERS
OR SQUALLS ARE POSSIBLE OVER THE WESTERN PART OF THE STATE.
TRAVEL MAY BE IMPACTED PARTICULARLY OVER THE WESTERN MTNS ON
SUNDAY DUE TO A COMBINATION OF BLUSTERY WINDS, SLIPPERY ROADS
AND REDUCED VISIBILITY.
--------------------------------------------------------------
LOOK FOR IMPROVING CONDITIONS EARLY NEXT WEEK WITH NO
PRECIPITATION AND MODERATING TEMPERATURES MONDAY & TUESDAY.
PRECIPITATION CHANCES WILL INCREASE INTO THE MIDDLE TO LATER
PART OF NEXT WEEK IN RESPONSE TO AN AMPLIFYING UPPER TROUGH
CARVING OUT OVER THE EASTERN US. MODERATING/ABOVE NORMAL TEMPS
INTO WEDNESDAY ARE FORECAST TO TREND COLDER TO MORE TYPICAL
LEVELS FOR MID JANUARY BY THURSDAY AND FRIDAY.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
18Z UPDATE... MOSTLY MVFR/FUEL ALTERNATE RESTRICTIONS AND AREAS
OF LIGHT RAIN ARE IN PLACE THIS AFTERNOON, ALONG AND AHEAD OF
AN INCOMING FRONTAL SYSTEM. WE HAVE HIGH CONFIDENCE THAT THIS
PATTERN WILL REMAIN FAIRLY STAGNANT INTO THE EARLY EVENING.
DURING THE EVENING HOURS, THE ABOVE MENTIONED FRONT IS EXPECTED
TO SLOWLY TRUDGE ACROSS PA FROM WEST TO EAST. ONCE THIS SYSTEM
GOES BY, WE ANTICIPATE AN END TO THE LIGHT RAIN. HOWEVER, LOWER
CEILINGS (FUEL ALTERNATE, OR PERHAPS IFR), DUE TO UPSLOPE W-NW
FLOW, SHOULD BE IN PLACE ACROSS THE ALLEGHENIES (KJST AND KBFD).
THERE IS RELATIVELY HIGH CONFIDENCE IN THIS SCENARIO.
FARTHER EAST, HOWEVER, THROUGH THE RIDGE AND VALLEY REGION, AS
WELL AS THE SUSQUEHANNA VALLEY CORRIDOR (KAOO, KUNV, KIPT,
KMDT, AND KLNS), ENOUGH LOW-LEVEL DRYING (WITH DOWNSLOPING W-NW
FLOW HELPING) COULD SET IN TO PROMOTE AT LEAST PARTIALLY
CLEARING SKIES. SHOULD SUCH CLEARING DEVELOP, IT BEGS THE
QUESTION WHETHER FOG WILL FORM OR NOT. IT WILL BE A BATTLE
BETWEEN THE AFOREMENTIONED DRY ADVECTION AND DAMP GROUND
CONDITIONS/SOME RADIATIONAL COOLING. CONFIDENCE IN BOTH CLEARING
SKIES AND FOG FORMATION IS FAIRLY LOW (20-40%) AND HOPEFULLY
WE'LL BE ABLE TO NAIL THIS DOWN MORE IN SUBSEQUENT UPDATES.
SATURDAY MORNING, THERE IS FAIRLY HIGH CONFIDENCE THAT MOISTURE
WILL INCREASE AGAIN IN ADVANCE OF A STRONGER COLD FRONT, WHICH
WILL BE APPROACHING FROM THE WEST. THUS, WE HAVE GENERALLY
DETERIORATING CONDITIONS (LOWER CEILINGS AND THE RE-EMERGENCE OF
LIGHT RAIN) WITH TIME, PARTICULARLY AFTER 13-15Z.
OUTLOOK...
SUN...SCATTERED SNOW SHOWERS ANTICIPATED, MAINLY IN THE VICINITY
OF KBFD AND KJST.
MON...A FEW LINGERING LAKE EFFECT SNOW SHOWERS EARLY, GIVING WAY
TO MAINLY VFR CONDITIONS.
TUE INTO WED...MAINLY VFR.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...STEINBUGL
KEY MESSAGES...STEINBUGL
DISCUSSION...STEINBUGL
AVIATION...JUREWICZ
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