409
FXUS61 KCTP 100232
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
932 PM EST FRI JAN 9 2026
WHAT HAS CHANGED
LINE OF LOW-TOPPED CONVECTION HAS FALLEN APART AND DISSIPATED.
ADDING FOG TO ALL THE AREA FOR LATER TONIGHT.
KEY MESSAGES
1) TIMING AND LOCATION OF ANY CLEARING WILL DETERMINE WHERE FOG
DEVELOPS. COOL AND WET ON SATURDAY.
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...
FOG HAS BEEN FORMING IN THE UPSLOPE/NIL FLOW IN THE CENTRAL
MOUNTAINS. THE ADVENT OF WIND IN THOSE PLACES HAS STARTED TO
IMPROVE VISIBILITY. CLEARING OF LOW CLOUDS IS A LITTLE BETTER
THAN PROGGED, WHICH IS A PLUS FOR FOG FORMATION, ESPECIALLY
LATER TONIGHT WHEN THE WIND SHOULD GET LIGHTER ALMOST
EVERYWHERE AS THEY VEER TO THE EAST. WE WILL EXPAND THE MENTION
OF TO ALL THE CWA LATER TONIGHT.
PREV...
WARM CONDITIONS IN PLACE THIS AFTERNOON WITH TEMPERATURES
LARGELY IN THE 40S WHILE A FEW LOCALES IN THE LAURELS SIT IN THE
50S. LIGHT RAIN SHOWERS WILL COME TO AN END BY EARLY THIS
EVENING AS A WEAK COOL FRONT PUSHES THROUGH CENTRAL PA.
TRANSIENT SURFACE RIDGING WILL MOVE IN TONIGHT AND EARLY
SATURDAY, PROVIDING A LULL/BREAK IN RAIN INTO SATURDAY MORNING
WHILE SETTING UP A COLD AIR DAMMING WEDGE PATTERN. PATCHY FOG
LOOKS LIKE A DECENT BET, BUT THE AMOUNT OF ANY CLEARING WILL
DETERMINE LONGEVITY AND PLACEMENT. HI-RES MODELS SHOW
OVERRUNNING PRECIP RETURNING NORTHWARD BY SATURDAY AFTERNOON
WHICH WILL RESULT IN A RATHER UNPLEASANT/CHILLY/DANK START TO
THE WEEKEND. MAY HAVE TO MONITOR THE NORTHERN TIER INTO SULLIVAN
COUNTY FOR A BRIEF PERIOD OF FREEZING RAIN/DRIZZLE, BUT 850 MB
THERMAL RIDGING ALONG WITH DIURNALLY WARMING TEMPERATURES SHOULD
PRECLUDE MUCH IF ANY THREAT BY THE TIME PRECIPITATION BEGINS
FALLING. RAIN TOTALS ON SATURDAY ARE EXPECTED TO BE HIGHER THAN
TODAY (FRIDAY) WITH WIDESPREAD 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 LOW LEVEL CAA/STEEPENING
LAPSE RATES PROMOTING DEEP BOUNDARY LAYER 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 NORTHWEST HALF OF
CENTRAL PA BY 7AM SUNDAY BEHIND THE OCCLUDED FRONT.
KEY MESSAGE 3...
SECONDARY COLD FRONT WILL DELIVER A COLDER/MORE SEASONAL
WEST/NORTHWEST 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 NORTHWEST 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 /02Z SATURDAY THROUGH WEDNESDAY/
CURRENT OBSERVATIONS OUTLINE MVFR CEILINGS ACROSS THE WESTERN
TERMINALS WHERE THE COLD FRONT IS TRACKING ACROSS CENTRAL
PENNSYLVANIA WITH THE BULK OF MODEL GUIDANCE CONTINUING TO
OUTLINE IFR/LIFR CEILINGS OVERNIGHT AT BFD/JST AS WINDS BEGIN TO
SLOWLY TAPER DOWN AS THE FRONTAL PASSAGE CONTINUES TO TRUCK
EAST OF THE FORECAST AREA. INCREASING CONFIDENCE IN LIFR
CONDITIONS WITH FOG FORMATION CLOSE TO BFD; HOWEVER, QUESTION
REMAINS ON IF FOG FORMATION OCCURS LOW ENOUGH ON THE RIDGETOPS
SURROUNDING THE AIRFIELD. RAINFALL TRACKING OVER THE AIRFIELD
RECENTLY IS A TIP TOWARDS THE RIGHT DIRECTION; HOWEVER, IF WINDS
REMAIN GUSTY THROUGHOUT MUCH OF THE EVENING, A SOLUTION
FAVORING HIGH-END IFR IS PLAUSIBLE TO WIN OUT. MAIN TIMING OF
FOG CONCERNS WOULD COME IN THE 06-10Z TIMEFRAME; HOWEVER, CANNOT
RULE OUT LONGER DURATION LIFR CONDITIONS IF FOG DOES MANAGE TO
SETTLE OVER THE AIRFIELD. FURTHER SOUTH, LOWER CONFIDENCE OF FOG
FORMATION AT JST AS DEW POINT DEPRESSIONS REMAIN RELATIVELY
HIGHER COMPARED TO THAT OF BFD.
ACROSS SOUTHEASTERN PENNSYLVANIA, RAINFALL HAS TRACKED EAST OF
THE REGION WITH IFR CEILINGS CURRENTLY OBSERVED AT MDT/LNS. A
COMBINATION OF RAP/GLAMP MODEL GUIDANCE CONTINUES TO INDICATE
FAVORABLE CHANCES (> 80%) FOR IFR CEILINGS CONTINUING THROUGH
THE 02Z-04Z SATURDAY TIMEFRAME. PROGRESSING PAST 04Z, ODDS TIP
TOWARDS FAVORING VFR CONDITIONS (BRIEF PERIODS OF MVFR POSSIBLE
BETWEEN 04-05Z) AT MDT/LNS WITH SOME EROSION OF THE LOW LEVEL
CLOUD DECK OUTLINED ON HREF/RAP MODEL GUIDANCE. VFR CONDITIONS
ARE EXPECTED TO CONTINUE THROUGH ~15-17Z SATURDAY (60-70%
CONFIDENCE) BEFORE THE NEXT SYSTEM BRING RAINFALL NORTHWARDS
ACROSS ALL OF CENTRAL PENNSYLVANIA. AS RAINFALL ENTERS THE
FORECAST AREA SOUTH-TO-NORTH, EXPECT WIDESPREAD DETERIORATION
IN FLYING CONDITIONS ACROSS CENTRAL PENNSYLVANIA WITH MODEL
CONSENSUS BETWEEN RECENT RAP/GLAMP/HREF MODEL GUIDANCE
INDICATING WIDESPREAD IFR CONDITIONS ARE LIKELY (> 70%
CONFIDENCE) AFTER A BRIEF WINDOW OF MVFR CEILINGS/VISIBILITIES
WITHIN RAINFALL. LIFR REMAINS MOST PLAUSIBLE BASED ON RAP MODEL
GUIDANCE AT MDT/LNS WHERE AMPLE LOW-LEVEL MOISTURE WILL BE IN
PLACE. LLWS CONCERNS ALSO BEGIN TO BE INTRODUCED AFTER 20Z
SATURDAY; HOWEVER, BASED ON RECENT NBM/NAM MODEL GUIDANCE HAVE
DECIDED TO LIMIT MENTIONS TO BFD DUE TO SLIGHTLY HIGHER (30-40%)
CONFIDENCE IN LLWS CRITERIA BEING MET AT THE AIRFIELD.
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-WED...MAINLY VFR.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...GUSEMAN/DANGELO/STEINBUGL
KEY MESSAGES...GUSEMAN/STEINBUGL
DISCUSSION...GUSEMAN/DANGELO/STEINBUGL
AVIATION...NPB
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