Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 212255 AFDCTP Area Forecast Discussion National Weather Service State College PA 555 PM EST Sun Jan 21 2018 .SYNOPSIS... A warm front drifting slowly north across the region will bring some 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 today and stay there through early Tuesday, before falling back to near or slightly below normal Wednesday and Thursday. A rebound in temperatures to above normal levels will occur again for 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 the cool 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 /00Z MONDAY THROUGH FRIDAY/... 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. The best chance for organized rain showers is right before the warm fronts moves through. Timing for a line of showers is very consistent cross- models around 10-15Z. These showers will not last very long as they pass over. The highest chance for showers is over BFD and lower in JST/UNV/AOO/IPT. MDT and LNS will likely not have those showers in the morning but could still have some DZ before the warm front passes. The late morning and afternoon will hold a significant improvement across the south - VFR and even big breaks in the clouds. Everyone else will likely improve to MVFR and also dry out. An LLWS problem will develop overhead on Monday afternoon and evening as a very strong low level jet cranks up ahead of the cold front. The stable/mainly calm surface layer will be topped by a belt of 50-60kt SSWrly winds just 2-3kft aloft. Cold front moves into the west later Mon night but widespread, potentially gusty SHRA are expected and even an isold TS is possible before the cold front clears the eastern terminals mid-day Tues. Outlook... Tues PM-Wed...IFR SHSN NW. MVFR/VFR SE. Thurs-Fri...No sig wx. && .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 NEAR TERM...Dangelo/Evanego SHORT TERM...Dangelo/Evanego LONG TERM...Lambert/RXR AVIATION...Dangelo/Fitzgerald HYDROLOGY... is the U.S. government's official web portal to all federal, state and local government web resources and services.