Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 231905 AFDCTP Area Forecast Discussion National Weather Service State College PA 205 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 /THROUGH TONIGHT/... Sunshine in the SErn half of the area will continue to cook the temps up to their full adiabatic, and even super-adiabatic, potential. Just a few sfc-based cu right now - mainly out the south-facing window here at the office. These are rather flat but do have some moderate vertical extent to them. If it gets a few more degs hotter, some showers will pop - and slide eastward through the evening. Will keep POPs highest S of UNV and IPT, and limit them to 60 or less due to expected areal coverage. Showers are likely across the northwest and chc POPs on order for the rest of the N as warm air to the south of a diffuse front pushes northward - again. Temps should be 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 /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 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 withing the developing southwest flow aloft will bring several weak fronts across the region. This will lead to less than pristine sky conditions...but 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 /19Z THURSDAY THROUGH TUESDAY/... VFR should be the rule for the next 6 hours in most places, but for BFD where the low clouds may take another hour or two to lift/break-up. The winds will stay gusty through sunset. Sct- nmrs SHRA will pop up in the NW later this evening and lift northward ahead of the diffuse and hard to pinpoint warm front currently somewhere overhead. Diurnal showers and perhaps a TSRA are expected to pop up within the next few hours SE of UNV and slide to the east. Moderate cu out there already and even some TCU almost through the second capping inversion around 700mb. Any SE showers should be gone by 03z and could leave some dense fog in their wake as the sky may clear out afterward and wind go light. The clouds will likely lower some over all of the area tonight and drop us into MVFR at most sites. A few - namely BFD - will go back to IFR cigs. Daylight on Friday will begin the process of drying and deepening the mixed layer. Little to no precip is expected until late Fri night when a strong cold front will push through from W-E. SH/TSRA will accompany the front and may pop up ahead of the front, but overnight stability will keep those to a minimum. The stability will also mean that we will have LLWS due to the strong warm advection/S wind ahead of the front. Outlook... Sat...LLWS. Strong FROPA with sub-VFR likely in moderate rain showers and sct TS. Post-frontal WNW wind gusts 25-35kts. Sat night-Sun...Sub-VFR NW third with sct shsn. Gusty NW wind. Mon...Reduced CIGs psbl in RA/SN. && .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 SHORT TERM...Dangelo LONG TERM...Lambert/Gartner AVIATION...Dangelo CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.