Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 200148 AFDCTP Area Forecast Discussion National Weather Service State College PA 848 PM EST Mon Feb 19 2018 .SYNOPSIS... Rain should shift north of the PA/NY border tonight as mild air begins to move into central PA. A spring-like surge of record- challenging warmth is expected Tuesday and Wednesday with temperatures 25 to 35 degrees above average - making it feel more like May than February. Expect the anomalous warmth to be trimmed back later in the week but readings will stay above average for this time of year. Periods of rain are likely during the second half of the week into the weekend with brief intervals of mixed precipitation possible over north-central PA Wednesday night into early Friday morning. && .NEAR TERM /UNTIL 7 AM TUESDAY MORNING/... Rain on track to lift out of that northern-most tier of PA counties slowly through the next 3-4hrs. Fog has already begun to get thick in spots across the south where clouds briefly broke up. Will continue to mention fog across most of the area overnight. The Laurels and perhaps Warren/McKean counties could be spared the fog. However, it could get dense elsewhere. Will keep an eye on the conditions for a dense fog advy (widespread <1/4sm). Prev... Meso analysis at 2PM shows the warm front from central OH eastward into NRN WV then down stacked up into the mountains of western VA. Locally the nose of a SW LLJ is helping force some warm advection/isentropic lift and an area of steady light- moderate rain over about the northern 2/3 of my CWA. The synoptic scale warm front is made to pass into NY state this evening while the low level feature, a remnant of cool air damming is slower to move northward through the Central Mountains. The bulk of the rain will lift north with the deepest forcing during the evening hours with the remainder the forecast area seeing mainly damp conditions with areas of fog and maybe some patchy drizzle. Can`t completely rule out a rumble of thunder across the NW where the models develop some modest instability. Western higher terrain will tend to see the warm air mix down first overnight with some breaks in the clouds and not as much misty fog or drizzle. Temperatures will be steady or slowly rising over most of the area overnight as southerly flow freshens. && .SHORT TERM /7 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... Tuesday will bring an early taste of spring as the warm air mixes down to the surface over all of the forecast area bringing near record warmth. Even conservatively mixing to just 925mb should yield max temps of 70-75F over the southern part of the forecast area, with the coolest temps across the northern mountains where they will hold onto clouds and a small chance of showers the longest. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... *Record-challenging warmth Tuesday night through Wednesday *Periods of rain with a brief interval of mixed precip possible Wed. night- AM Fri. over north central PA *Pattern favors above average temperatures this weekend into next week A very mild, spring-like start to the period with patchy fog Tue ngt into AM Wed. giving way to a mix of clouds and sun with near-record to record high temps across much of central PA. Rain showers will accompany a cold front NW-SE across the area from midday Wednesday through Wednesday evening. The front will become quasi stationary near the MD line Wed. night. The wavy frontal boundary will bring periods of rain into the weekend, with an interval of mixed wintry precip possible north of the front over north-central PA between Wed. night and early Friday morning. Confidence is low on the ptype details but there is at least some risk for a light snow and/or ice accumulation. Another round or two or rain is likely over the weekend. We will need to monitor the potential for flooding especially across south- central PA where the ground is very saturated from previous rain/snowmelt and streamflows are well above normal. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... The warm front continues to lift to the north and the predominate IFR cigs and vsbys are slowly improving. In a bit of a reversal, BFD, JST and UNV are all VFR with IFR cigs still possible at BFD, while AOO, IPT, MDT and LNS are all IFR and lower in cigs and vsbys. Expect the IFR and lower to continue as it is based on trapped moisture and due to the calm winds. Once the inversion lifts tomorrow morning, between 13Z to 15Z, expect for these conditions to improve. There is also the potential for LLWS with SW flow just off the deck around 40-50 kts. So all terminals will improve to VFR by mid to late morning. Bradford will be the exception with the warm front hanging close by keeping sub VFR conditions in place most if not all day. Outlook... Wed...Restrictions likely in rain showers mainly NW half. Thu-Sat...Intermittent restrictions in rain showers . && .HYDROLOGY... Recent rainfall and snowmelt has resulted in very saturated soil and well above normal streamflows across much of the area especially south-central PA. Rainfall of 0.50 to 1.00 inch is forecast between Wednesday and Thursday night, with additional rainfall likely into/over the weekend. River flood potential (including small streams, creeks and tributaries) is above normal and we will continue to monitor the risk in the coming days. && .CLIMATE... Record highs for selected sites for Tuesday and Wednesday February 20th and 21st: MDT: 72/1930;71/1997 IPT: 67/2016;69/1930 BFD: 58/2016;64/1997 AOO: 62/2016;71/1997 && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte/Steinbugl NEAR TERM...Dangelo/La Corte SHORT TERM...La Corte LONG TERM...Steinbugl AVIATION...La Corte/Ceru HYDROLOGY... CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.