Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 072144 AFDCTP Area Forecast Discussion National Weather Service State College PA 444 PM EST Sat Dec 7 2019 .SYNOPSIS... After a fair weather weekend, a volatile and stormy pattern is expected during the second week of December. Temperatures are forecast to surge well-above normal Monday and Tuesday, followed by a sharply colder trend Wednesday into Thursday. The brief warm-up will be accompanied by periods of rain which may end as light snow Tuesday night. A mid to late week drying trend will likely reverse by next weekend with another storm system on the horizon. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Mainly clear skies expected tonight with min temps in the teens and 20s. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... Clouds increase on Sunday with max temps rebounding 5-10 degrees over the western Alleghenies. Dry wx will hold during the day with POPs steadily increasing later Sunday night into early Monday morning. Leaned toward hires blend/HREF with highest precip probs in the far southeast zones by daybreak. QPF will be very light and with southeast flow could almost see a more misty/foggy/drizzle type pattern developing. Thermal profiles are very marginal particularly over the interior central mtns where some spotty light frozen/freezing precip is possible especially when considering wet-bulb effects. That said, sfc temps generally AOA 32F suggest little to no impact as predominant ptype becomes rain into later Monday morning. && .LONG TERM /MONDAY THROUGH SATURDAY/... Big temperature swings are expected during the period. A significant warming trend is forecast early next week with max temperature departures +10-15 degrees above normal (widespread 40s and 50s). Unseasonably mild minimum temps are forecast Monday night with departures on the order of 15-20 degrees above normal as the primary PWAT axis (with values around +2 sigma) slides east across the region. The mild surge will be accompanied by periods of light to moderate rain Monday and Tuesday. Rainfall amounts between 0.50 to 1 inch are forecast early next week. The warm air and rainfall will help to melt the snow over the Allegheny Front into the Upper Susquehanna River basin. Areas of fog are likely as the mild air moves over colder ground. Rises on rivers/streams are expected and will need to monitor risk of minor flooding across the northern tier. WPC indicates a MRGL risk of rainfall heavy enough to cause flooding of small streams and poor drainage areas over our far SW counties Monday into early Tuesday. It will turn sharply colder midweek as arctic air blasts into the region. Temperatures will be on the decline over the NW Tuesday afternoon (non diurnal over the NW half) and drop quickly Tuesday night areawide. There will be some potential for residual water or slush to freeze up quickly by Wednesday. Highs are forecast to drop by 20-30 degrees between Tuesday and Thursday, with minimum wind chills in the single digits and teens Thursday morning. There is also a chance that the cold air could catch up to the back edge of the rain and result in a period of snow at the end of the precipitation event on Wednesday. There should be some lake effect snow that develops in the wake of the system, but trajectories appear to be focused more into southwest NY. Strong 1040+mb high pressure moves NE across the region Thu/Fri. The more active weather pattern may continue into next weekend with the GFS and ECMWF both showing a large, dynamic storm system bringing some modified tropical air up the eastern seaboard, potentially impacting portions of our region. && .AVIATION /22Z SATURDAY THROUGH THURSDAY/... VFR conditions this afternoon through 18z Sunday. Cirrus clouds with cigs >25000ft will move through the airspace overnight. Will have to watch potential for swrly LLWS of 40+ kts starting in BFD Sunday afternoon/evening and overspreading the rest of the area Monday afternoon into Tuesday morning, as a few waves of low pressure pass to our west. Cigs and vis will be reduced in periods of rain Monday and Tuesday. .Outlook... Sun night...Lowering cigs. LLWS poss at BFD Mon-Tue...Widespread SHRA/MVFR. IFR and LLWS poss. CFROPA Tues. Wed...Restrictions NW half. Breezy NW wind.&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM...Steinbugl LONG TERM...Lambert/RXR/Steinbugl AVIATION...Banghoff/Colbert

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