Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 240108 AFDCTP Area Forecast Discussion National Weather Service State College PA 808 PM EST Thu Feb 23 2017 .SYNOPSIS... Our extended period of very mild weather will continue into Saturday morning. A strong cold front will push east across the region on Saturday and create showers and perhaps some gusty thunderstorms. Gusty westerly winds, colder temperatures, and snow showers across the western mountains will follow the frontal passage. A wave of low pressure moving up the Ohio River Valley on Monday may bring some mixed precipitation to the northern half of the area and rain in the south. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Current hourly temperatures running 20 to 30 degrees above normal for mid to late February. Afternoon heating and dewpoints in the lower 50s and 700-850 mb theta-e ridges over the Ridge and Valley Region and along the Allegheny Plateau allowed isolated showers to sprout late this afternoon and survive into the early evening hours. These showers should die out by late evening, but deep layer moisture continues to increase across the region ahead of an approaching shortwave trough from the Ohio Valley. This will keep chc for showers going there through 12z. Temps much slower to drop off this evening than last with lots of lower clouds over the west and potential for clouds with and after any showers in the SE. Fog is again possible and could become dense where the rain does fall this evening/overnight. Mins will be lofty with 50s widespread. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... The waggling front should be north of the NY border and moving north by sunrise on Friday. The clouds and fog around in the morning will clear out very nicely from S-N, but it may take until late afternoon in the north. It will be very warm and near records again. We will start the day near 50 or better and go with maxes in the 70s for most - and it is not out of the question that someone in a southern valley urban area get to 80F. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Upper ridging over the east coast at the start of the period will be temporarily squashed as a decent northern stream shortwave moves east through the Ohio Valley and across the Middle Atlantic states over the coming weekend. This will bring a pronounced cold front across the region during the day Saturday. Heights are forecast to rebuild across the eastern half of the conus early next week on broad southwesterly flow ahead of troffing developing over the Rockies. The aforementioned cold front will return temps to near or closer to near seasonal normals for Sunday into early next week. Several shortwaves within the southwest flow aloft will bring several weak fronts across the region next week. This will lead to less than pristine sky conditions...but most of the time period will be generally dry. However, enough low pressure lurking at the surface could lead to a system of more significance sometime during the week. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/...
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A dying cold front will stall out at it pushes into northern Pa this evening. Widely scattered showers have formed this evening in the unstable air mass ahead of the front over central Pa. These showers could produce a brief visibility reduction in a few spots this evening. However, the bigger concern will come after midnight, when radiational cooling leads to areas of low CIGS/fog. A plume of low level moisture ahead of the dying front, combined with diminishing wind and radiational cooling, should yield some late night fog. Latest SREF output indicating the eastern half of the state will be most susceptible to a period of IFR visibility early Fri morning. At BFD, a period of IFR conditions appears likely late tonight, as frontal boundary returns north as a warm front, accompanied by showers and low CIGS. Model soundings strongly indicating that any early VIS/CIG reductions over northern and eastern Pa will give way to widespread VFR conditions by late morning, as low level moisture mixes out. Bufkit soundings indicate southerly winds will increase during the late morning and afternoon, with gusts to near 20kts. Outlook... Sat...AM fog/LLWS possible eastern Pa. Strong daytime FROPA, accompanied by line of shra/tsra. Becoming windy late with evening snow showers/reduced VIS possible at BFD/JST. Sun...Windy. Mon...Slight chance of light snow/reduced VIS northern Pa. Tue...Showers/reduced CIGS possible, especially northwest Pa.
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&& .CLIMATE... ***February Warmth 2017*** Updated 2/22/17 at 8am EST Record high temperatures for select sites for Feb. 23-24: ---------------------------------------------------------- Harrisburg 2/23: 70 in 1985 Harrisburg 2/24: 75 in 1985 Williamsport 2/23: 70 in 1985 Williamsport 2/24: 71 in 1985 Altoona 2/23: 66 in 1977 Altoona 2/24: 69 in 1985 Bradford 2/23: 57 in 1977 Bradford 2/24: 59 in 1961 ----------------------------------------------------------- Most 60 degree days in February at Harrisburg. Based on the latest forecast, add 4 more days to the list and finish tied for second with 7 days. 1. 10 days in 1976 2. 7 days in 1930 3. 5 days in 1991, 1943 5. 4 days in 1997, 1985, 1954, 1939 9. 3 days in 2017, 2016, 1996, 1990, 1961, 1932, 1890 ------------------------------------------------------------ Warmest February on Record (Avg. Temperature through 2/21) Harrisburg: 2017 rank=4 (38.6) 1. 40.4 in 1998 2. 39.6 in 1976 3. 39.4 in 1954 Williamsport: 2017 rank=4 (35.4) 1. 37.0 in 1998 2. 36.1 in 1954 3. 35.6 in 2002 Altoona: 2017 rank=2 (36.5) 1. 37.4 in 1976 Evening cooling will be a little slower than last night. Bradford: 2017 rank=6 (29.3) 1. 32.3 in 1998 2. 30.1 in 2002 3. 29.6 in 2012 4. 29.5 in 1990/1976 ------------------------------------------------------------- && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo/Lambert NEAR TERM...Dangelo/DeVoir SHORT TERM...Dangelo LONG TERM...Lambert/Gartner AVIATION...Fitzgerald CLIMATE...

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