951
FXUS61 KCTP 090001
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
701 PM EST THU JAN 8 2026
WHAT HAS CHANGED
REFINED RAINFALL TIMING ON FRIDAY, ESPECIALLY ACROSS THE SOUTH-
CENTRAL MOUNTAINS WHERE LOW-LEVEL DRY AIR COULD SLOW DOWN THE
EASTERN PUSH OF PRECIPITATION. NEWEST FORECAST ALSO TRENDS DOWN
WITH RESPECT TO ELEVATED INSTABILITY (AND THUS THUNDERSTORM
POTENTIAL) ON FRIDAY/SATURDAY ACROSS THE SOUTHERN TIER OF
PENNSYLVANIA. INCREASED WIND GUSTS ON SUNDAY AND MONDAY UNDER
THE PRESENCE OF A 850MB LLJ THAT COULD BRING WIND GUSTS INTO
ADVISORY RANGE (STILL TOO FAR OUT AND TOO LOW CONFIDENCE FOR
HEADLINES). ALSO, KNOCKED DOWN TEMPERATURES SLIGHTLY ON SATURDAY
WITH COLD AIR DAMMING POTENTIAL ACROSS S/E PA.
KEY MESSAGES
1) MILD CONDITIONS CONTINUE THROUGH SATURDAY EVENING WITH
PERIODS OF RAIN ACROSS MUCH OF CENTRAL PENNSYLVANIA.
2) MONITORING POTENTIAL FOR ICE JAMS ACROSS NORTHERN
PENNSYLVANIA, PRIMARILY NORTH OF THE INTERSTATE 80 CORRIDOR.
3) BREEZY TO GUSTY WINDS BEGIN ON SUNDAY AND CONTINUE THROUGH
MONDAY WITH LAKE EFFECT SHOWERS (AND POTENTIALLY SQUALLS)
INCREASINGLY LIKELY TO BRING SNOW ACCUMULATIONS TO FAVORED
LOCATIONS IN WESTERN PENNSYLVANIA.
4) DRY AND NEAR-AVERAGE TEMPERATURES ON MONDAY AND TUESDAY
BEFORE A WARMING TREND AND UNSETTLED PATTERN BEGINS FOR THE
MIDDLE OF THE WEEK.
DISCUSSION
KEY MESSAGE 1...MILD CONDITIONS CONTINUE THROUGH SATURDAY
EVENING, PERIODS OF RAIN ACROSS MUCH OF CENTRAL PENNSYLVANIA.
INFLUENCE OF HIGH PRESSURE CONTINUES IN THE NEAR-TERM WITH HIGH
CLOUDS FILTERING IN ACROSS THE REGION. RECENT HREF MODEL
GUIDANCE CONTINUES TO DEPICT SOME BREAKS IN CLOUD COVER OVER THE
NEXT COUPLE OF HOURS BEFORE INCREASING OVERNIGHT AHEAD OF AN
APPROACHING LOW PRESSURE SYSTEM WITH INCREASING LOW-LEVEL
MOISTURE SUGGESTING AN ARRIVAL TIME OF RAINFALL NEAR 12Z/7AM
ACROSS THE WESTERN PERIPHERY OF THE FORECAST AREA. RECENT
HREF/RAP MODEL GUIDANCE DOES INDICATE LOW-LEVEL DRY AIR WINNING
OUT ACROSS PORTIONS OF THE SOUTH-CENTRAL MOUNTAINS, PROMOTING A
SLIGHTLY DELAYED ARRIVAL TIME CLOSER TO THE LATE MORNING HOURS
WHICH IS IN GOOD AGREEMENT WITH RECENT NBM MODEL GUIDANCE. THESE
SLIGHT CHANGES HAVE BEEN OUTLINED IN THE NEWEST FORECAST WHICH
DOES HAVE SOME SLIGHT DEVIATIONS FROM THE PREVIOUS FORECAST
CYCLE. AFTER 18Z/1PM EST FRIDAY, INCREASING PWATS OUTLINED IN
HREF/RAP MODEL GUIDANCE INDICATE PWATS IN THE 1.00-1.25" RANGE
ACROSS PORTIONS OF SOUTHEASTERN PENNSYLVANIA, WHERE MODERATE
RAIN MENTIONS HAVE BEEN ADDED TO INCORPORATE A HEAVIER BAND OF
RAINFALL ACROSS THE LOWER SUSQUEHANNA VALLEY ALONG THE COLD
FRONTAL PASSAGE.
SOME UNCERTAINTY BEGINS TO CREEP INTO THE FORECAST IN THE
FRIDAY NIGHT TO SATURDAY NIGHT TIMEFRAME, WITH RECENT MODEL
GUIDANCE BEGINNING TO INTRODUCE A SLIGHT DECREASE IN RAINFALL
MENTIONS. THIS DECREASE APPEARS TO BE WELL-FOUNDED WITH THE
PRESENCE OF SUBSIDENCE INVERSION AND DRY AIR ALOFT ON RECENT
RAP/NAM MODEL SOUNDINGS. THE MAIN CONCERN FOR KEEPING SOME
PRECIPITATION MENTIONS WILL BE THE POTENTIAL OF A STATIONARY
BOUNDARY SETTING UP JUST SOUTH OF THE PA-MD BORDER THAT WOULD
ALLOW FOR PRECIPITATION MENTIONS TO BE RETAINED. FOR THIS
FORECAST CYCLE, HAVE DECIDED TO KEEP WITH NBM POPS IN THIS
TIMEFRAME, BUT COULD REALISTICALLY SEE AN INCREASE/DECREASE IN
MENTIONS FRIDAY NIGHT DEPENDING ON WHERE THE FRONTAL BOUNDARY
SETS UP BEFORE INCREASING MOISTURE SATURDAY MORNING ALLOWS FOR
THE SECOND PERIOD OF RAINFALL TO OVERSPREAD SOUTH-TO-NORTH
ACROSS THE REGION AND CONTINUING THROUGHOUT THE DAY ON SATURDAY.
ANOTHER ASPECT OF THE FORECAST (NOT ENTIRELY A PART OF THIS KEY
MESSAGE BUT STILL WARRANTS MENTION) TO KEEP AN EYE ON IS THE
POTENTIAL FOR COLD AIR DAMMING ACROSS EASTERN/SOUTHEASTERN
PENNSYLVANIA. RECENT NBM MODEL GUIDANCE INDICATES A FAIRLY
EXPANSIVE SPREAD WITH REGARDS TO HIGH TEMPERATURES ON SATURDAY,
WITH PORTIONS OF SOUTHEASTERN PENNSYLVANIA SHOWING A 10-15F
RANGE BETWEEN THE 25TH AND 75TH PERCENTILES. GIVEN THE EVENT IS
APPROACHING AND THERE IS QUITE AN EXPANSIVE SPREAD, HAVE NUDGED
TEMPERATURES DOWN SLIGHTLY TO BE MORE IN LINE WITH A SLIGHT
DECREASING TREND IN MODEL GUIDANCE.
KEY MESSAGE 2...MONITORING POTENTIAL FOR ICE JAMS ACROSS
NORTHERN PENNSYLVANIA, PRIMARILY NORTH OF THE I-80 CORRIDOR.
THE AFOREMENTIONED MILD TEMPERATURES ACROSS THE REGION, COUPLED
WITH RAINFALL WILL BRING ABOUT A NON-ZERO CHANCE FOR ICE JAMS
ACROSS PORTIONS OF CENTRAL PENNSYLVANIA ON FRIDAY WITH THE
THREAT CONTINUING INTO SATURDAY. ICE JAM THREAT WILL BE HIGHEST
NORTH OF INTERSTATE 80, WHERE ANY REMAINING SNOW ON THE GROUND
AND RIVER ICE WILL CONTINUE TO BREAK UP OVER THE NEXT COUPLE OF
MILD DAYS. WHILE WE'RE NOT EXPECTING ANY WIDESPREAD HYDROLOGIC
CONCERNS AT THIS TIME AND THUS NO THOUGHTS ON ISSUING ANY SORT
OF HEADLINE/MENTIONS IN PRODUCTS, IT IS STILL WORTH HIGHLIGHTING
THAT THERE IS A NON-ZERO CHANCE FOR ICE JAMS ON THE SMALLER
STREAMS OF NORTHERN PENNSYLVANIA.
FOR AREAS SOUTH OF INTERSTATE 80, THERE REMAINS LITTLE IN THE
WAY OF SNOW COVER AND TEMPERATURES ARE EXPECTED TO STAY ABOVE
FREEZING FOR THE NEXT ~36 HOURS WHICH WILL LIKELY ALLOW FOR
REMAINING RIVER ICE TO CONTINUE MELTING. THE AFOREMENTIONED
RAINFALL ALSO DOES NOT BEGIN ENTERING THESE AREAS UNTIL LATER IN
THE DAY FRIDAY, WHICH WILL LEAD TO LOWER ICE JAM CONCERNS.
KEY MESSAGE 3...BREEZY TO GUSTY WINDS BEGIN ON SUNDAY AND
CONTINUE THROUGH MONDAY WITH LAKE EFFECT SHOWERS (AND
POTENTIALLY SQUALLS) INCREASINGLY LIKELY TO BRING SNOW
ACCUMULATIONS TO FAVORED LOCATIONS IN WESTERN PENNSYLVANIA.
AS THE COLD FRONT PASSAGE MOVES EAST OF THE AREA, NORTHWESTERLY
FLOW KICKS UP THE TYPICAL LAKE EFFECT SNOW MACHINE ACROSS
NORTHWESTERN AND NORTHERN PENNSYLVANIA LATE SATURDAY NIGHT INTO
SUNDAY MORNING. RECENT GFS/NAM MODEL GUIDANCE CONTINUES TO
INDICATE SOME SNOW SQUALL POTENTIAL SUNDAY MORNING AND INTO THE
AFTERNOON HOURS ACROSS MAINLY NORTHERN AND WESTERN PENNSYLVANIA.
SQUALL POTENTIAL MIGHT SLIGHTLY DECREASED BASED ON RECENT MODEL
GUIDANCE; HOWEVER, POTENTIAL STILL EXISTS AND WILL CONTINUE TO
BE MONITORED AHEAD OF THE EVENT. CURRENT STORM TOTAL SNOWFALL
OUTLINES A CORRIDOR OF 1-2" ACROSS WARREN COUNTY; HOWEVER, THIS
DOES NOT ENCOMPASS THE ENTIRE EVENT AND ADDITIONAL SNOWFALL INTO
SUNDAY MORNING WILL NEED TO BE ASSESSED FOR WINTER WEATHER
ADVISORY CONCERNS.
WINDS BEHIND THE COLD FRONTAL PASSAGE ARE EXPECTED TO INCREASE
BEHIND THE COLD FRONTAL PASSAGE WITH A FAIRLY TIGHT PRESSURE
GRADIENT. GIVEN THIS TIGHT PRESSURE GRADIENT, NBM IS LIKELY
UNDERESTIMATING THE STRENGTH OF THE WIND FIELD, THUS HAVE
BLENDED IN WITH NBM 90PCT IN ORDER TO PUSH WIND/GUSTS HIGHER AND
PUSHING PORTIONS OF THE LAUREL HIGHLANDS CLOSER TO WIND
ADVISORY CRITERIA. TIME HORIZON ON LACK OF CONFIDENCE WARRANTS
HWO MENTIONS AT THIS TIME WHILE CONTINUING TO MONITOR THIS
THREAT AS IT COMES INTO FOCUS.
KEY MESSAGE 4...DRY AND NEAR-AVERAGE TEMPERATURES ON MONDAY AND
TUESDAY BEFORE A WARMING TREND AND UNSETTLED PATTERN BEGINS FOR
THE MIDDLE OF THE WEEK.
HIGH PRESSURE SOUTH OF THE AREA BUILDS IN FOR THE BEGINNING OF
THE WEAK, LEADING TO TRANQUIL WEATHER CONDITIONS WITH NEAR-
AVERAGE TEMPERATURES ON MONDAY. A SLIGHT WARMING TREND WITH
TRANQUIL WEATHER IS EXPECTED FOR THE BULK OF TUESDAY BEFORE THE
NEXT APPROACHING SURFACE LOW SOUTHERN CANADA TRACKS A COLD FRONT
ACROSS CENTRAL PENNSYLVANIA LATE TUESDAY INTO WEDNESDAY
MORNING.
TEMPERATURE PROFILES NEAR FREEZING ACROSS THE NORTHERN TIER AND
WESTERN PENNSYLVANIA WILL SUPPORT A WINTRY MIX AT ONSET WITH
RAINFALL THE PREDOMINANT PRECIPITATION TYPE AHEAD OF THE COLD
FRONTAL PASSAGE. COLD AIR FILTERING IN BEHIND THE FRONT WILL
LIKELY ALLOW FOR A TRANSITION TO SNOW ACROSS THE NORTHWESTERN
ALLEGHENIES AND THE LAUREL HIGHLANDS WITH WARMING TEMPERATURES
ALLOWING FOR RAIN ACROSS THE LOWER SUSQUEHANNA VALLEY WITH SOME
MIX IN BETWEEN THESE TWO LOCATIONS. THERE REMAINS A FAIR AMOUNT
OF UNCERTAINTY IN THIS TIMEFRAME; THUS, HAVE STAYED CLOSE TO NBM
MODEL GUIDANCE THIS FORECAST CYCLE.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
VFR CONDITIONS CONTINUE TONIGHT AS HIGH CLOUDS OVERSPREAD THE
AREA. AN AREA OF LOW PRESSURE THAT WILL TRACK TO OUR NORTHWEST
TOMORROW, BRINGING WIDESPREAD RAINFALL TO THE REGION. RAIN WILL
APPROACH BFD AND JST IN THE 14-16Z TIMEFRAME, GRADUALLY
SPREADING EASTWARD THROUGH THE MORNING AND INTO THE EARLY
AFTERNOON.
A 40 TO 55 KNOT SOUTHERLY LOW-LEVEL JET WILL MOVE INTO
PENNSYLVANIA OVERNIGHT, RESULTING IN A PROLONGED PERIOD OF LLWS.
SURFACE WIND GUSTS INCREASE THROUGH THE NIGHT, WITH GUSTS OF 20
TO 25 KNOTS POSSIBLE AT ALL TAF SITES.
A NARROW COLD FRONTAL RAINBAND ALONG A COLD FRONT WILL MOVE
THROUGH ON FRIDAY EVENING INTO THE OVERNIGHT HOURS AND SHOULD
WEAKEN/FIZZLE OUT WITH EASTWARD EXTENT. WINDS WILL SHIFT FROM
SOUTHWESTERLY AHEAD OF THE LINE TO NORTHWESTERLY BEHIND THE
LINE. A PERIOD OF STRONGER WINDS IS ALSO POSSIBLE.
OUTLOOK...
FRI NIGHT-SAT...RESTRICTIONS WITH A BATCH OF STEADY RAIN AND
COLD FRONT SAT NIGHT.
SUN...SNOW SHOWERS POSSIBLE MAINLY WEST OF UNV.
MON...A FEW LINGERING LAKE EFFECT SNOW SHOWERS EARLY, GIVING WAY
TO MAINLY VFR CONDITIONS.
TUE...MAINLY VFR.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...NPB
KEY MESSAGES...NPB
DISCUSSION...NPB
AVIATION...BANGHOFF/BAUCO
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