Area Forecast Discussion
Issued by NWS State College, PA

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562 FXUS61 KCTP 222359 AFDCTP Area Forecast Discussion National Weather Service State College PA 659 PM EST Wed Feb 22 2017 .SYNOPSIS... An extended period of very mild weather will continue into Saturday. A strong cold front is expected to bring showers and thunderstorms on Saturday. Gusty westerly winds, colder temperatures, and snow showers across the western mountains will follow the frontal passage for later Saturday into early Sunday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Yet another mild February evening across central PA with temperatures some 15 to 20 degrees above average. Final vestages of shower activity associated with lifting warm front are exiting my northeast counties. Localized fog now being reported over the northwest mountains, but should not last long given freshening southwest boundary layer flow late this evening. No low/mid clouds over the srn tier early this evening and for at least the first half of the night, it should remain pretty much clear aside from thin high clouds. This should allow better radiational cooling over the south/east. However, a moist swrly flow will probably cause/hold lots of low clouds and perhaps some DZ later tonight in the western highlands. Have also mentioned some patchy fog over all of the area as many locations should get down near the already- mild dewpoints. Mins will run between 45F E and 50F W. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Low clouds and mid-level moisture will make Thursday another day of struggling to see the sun. However, the extremely mild start (45-50F) to the day will yet again allow the temps to be very much above normal through the whole day. A shearing "cold" front will dip down into the northern tier. POPs are a difficult call. The morning will still hold some --SHRA or -DZ in the NW. Any fog should take a while to burn off with dewpoints so high. The warm sector and the passage of a very subtle short wave trough may pop some showers (probably no thunder) over SWrn PA and slide them to the east during the aftn. The warm front itself will be another focus for some convergence and sct showers. Maxes will be even warmer than today(Wed). 60s should be widespread with the warmest numbers in the south. The front will probably stall out for a short time Thurs night, but push northward as a warm front late. This feature will keep clouds around, and is yet another reason to remain very high on temps for Thurs night. Mins will again be 45-50F area-wide. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Upper ridging over the east coast at the start of the period will be temporarily squashed as a decent nothern 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 late Saturday. Heights are forecast to rebuild across the eastern half of the conus early next week ahead of troffing developing over the Rockies. Very mild temperatures will persist for the end of the week, likely reaching records levels at least in some locations once again Friday afternoon. 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 /00Z THURSDAY THROUGH MONDAY/... BFD will have the SHRA overhead move off to the E/NE shortly. But, there are still some IFR clouds just to the west. Therefore, I must be cautious in improving the conditions there. Elsewhere, VFR will hold for at least the first half of the night. However, a moist SW flow into the wrn mtns will bring the low clouds into KJST and renew them in KBFD. There may also be some patchy DZ or --SHRA later tonight. The decoupled sfc will allow for good but not ideal radiational cooling as there will still be some higher clouds around the rest of the area. Thus, will mention fog in many locations, but not go into IFR outside of the wrn terminals. A cfront will dip into the area from the N on Thurs and could make the entire day into one of IFR in KBFD. Elsewhere, the low clouds and fog should burn away and some instability in the south could allow for a SHRA or two. Timing would be in the aftn. The front will likely hang around Thurs night but then lift to the north early Friday. Outlook... Fri...IFR/MVFR psbl early - mainly N. Chance of rain mainly N. 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 from Feb. 22-24: ---------------------------------------------------------- Harrisburg 2/22: 71 in 1974 Harrisburg 2/23: 70 in 1985 Harrisburg 2/24: 75 in 1985 Williamsport 2/22: 66 in 1974 Williamsport 2/23: 70 in 1985 Williamsport 2/24: 71 in 1985 Altoona 2/22: 62 in 1974 Altoona 2/23: 66 in 1977 Altoona 2/24: 69 in 1985 Bradford 2/22: 57 in 1975 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 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 NEAR TERM...Dangelo/DeVoir 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.