Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 220129 AFDCTP Area Forecast Discussion National Weather Service State College PA 829 PM EST Sun Jan 21 2018 .SYNOPSIS... A warm front pushing slowly northward across the area will bring occasional light rain or drizzle into early Monday. A potent area of low pressure moving across the Great Lakes will push a trailing cold front through Pennsylvania on Tuesday. Temperatures will rise above normal and stay there through early Tuesday, before falling back to near or slightly below normal Wednesday and Thursday. A rebound to above normal temperatures will occur again by next weekend. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Warm front approaches overnight, keeping things rather murky and damp for much of central PA. Light rain, drizzle and patchy fog are expected, although rainfall should be light. Temps will remain relatively mild for late-January. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... Best upper-level forcing will pass through in the morning, and warm front should lift northward across the area. The front may decide to temporarily stall overhead, but will eventually try to push up into NY state. POPs drop off nicely by aftn, with all but perhaps the northern border seeing some drying. Maxes will be a function of both sun (or lack there of) and advection. Will hold onto 40s across the northeastern portion of the CWA, with most everyone else topping 50 degrees. Again, not bad for January. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... Another January thaw underway that will keep relatively mild weather ongoing into Tuesday. Departures should reach +10 to +15 degrees above average, peaking Monday in the NW and Mon into Tues in the SE. The progressive pattern will keep the mid/late week cool down rather brief before temperatures moderate/trend warmer into next weekend. By Monday afternoon, warm front will have lifted north of the region, bringing a period of mainly dry weather ahead of approaching low pressure area. Cold front crosses central PA Monday night with weak secondary low forming in the lee of the Appalachians supporting a period of enhanced rainfall over the eastern 1/2 of PA as front occludes into Tuesday morning on the order of 0.50-0.75". Not too shabby SW 50kt LLJ could also generate a rumble of thunder. River ice concerns are addressed in the hydrology section. Winds look rather blustery from later Tuesday into Wednesday on the backside of the low pressure system as colder air filters back in. Snow showers are likely downwind of Lake Erie into Wed night but should only amount to light accums. Dry wx under high pressure Thu-Fri with chilly starts to the day (especially in the east) with moderating temperatures heading into the weekend as the next (weaker) low pressure system lifts across the Great Lakes bringing chances for rain on Sat increasing into Sunday. && .AVIATION /01Z MONDAY THROUGH FRIDAY/...
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An increasingly moist southerly flow will overspread the area tonight in advance of low pressure across the Miss Valley. Orographic lifting of this moist flow will continue to yield LIFR cigs across the northern mountains (KBFD) overnight, while progressively higher cigs are expected further south. LIFR conditions noted at KUNV at 00Z, but a developing southerly breeze is expected to cause low level moisture to mix out and result in modest improvement there later tonight. VFR conditions noted across southeast Pa (KMDT/KLNS) at 00Z, but latest model soundings and MOS guidance support the idea of at least MVFR vsbys in light fog late tonight. Expect predominantly MVFR cigs at KJST overnight, where a southerly flow results in drying/downsloping off of adjacent higher terrain. Warm front is progged to lift into western Pa on Monday, resulting in a return to VFR conditions along the spine of the Alleghenies, including KJST and possibly KBFD/KAOO. Elsewhere, modest improvement will come slowly across the eastern half of Pa on the cold side of the front. LLWS problem will become a concern Monday evening, as a very strong low level jet overspreads the area ahead of an approaching cold front. Outlook... Tue...AM rain/low cigs poss, then windy with PM shsn poss w mtns. Wed...AM shsn possible w mtns. Thu-Fri...No sig wx expected.
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&& .HYDROLOGY... Marietta gage /MRTP1/ pretty much steady right now. Flow is likely going to stay low enough to keep the gage itself below caution stage for the next 2 days. But, local ice effects are still possible, though. The Flood Watch for this area lasts into Monday afternoon. Due to the mild temperatures, there is a potential for ice movement, but also deterioration/thinning with time. All places along rivers and streams that have significant ice buildup should monitor water levels closely for the next several days. The anticipated rainfall totals of 0.5 to 0.8 inches over the next 48 hrs is much less than we had a few days ago, and the ice is less pervasive/extensive due to our relatively mild temps (vs the period leading up to our previous significant rainfall). && .CTP WATCHES/WARNINGS/ADVISORIES... Flood Watch through Monday afternoon for PAZ065-066. && $$ SYNOPSIS...Dangelo/Evanego NEAR TERM...Evanego SHORT TERM...Dangelo/Evanego LONG TERM...Lambert/RXR AVIATION...Fitzgerald HYDROLOGY...

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