Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 201215 AFDCTP Area Forecast Discussion National Weather Service State College PA 715 AM EST Mon Feb 20 2017 .SYNOPSIS... An extended period of mild, spring-like weather with well above normal temperatures is expected through the end of the upcoming week. A weak cool front will push through the state late Tuesday and Tuesday night. A stronger cold front is expected for Friday into Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... IR Satellite loop at 0730Z continue to show some areas of bkn- ovc upslope stratus across portions of Cambria and Somerset counties, mainly to the west of route 219. This area lies at the nrn edge of a llvl Theta-E ridge, and within a 10-15kt NW wind at 925 mb (which is orthogonal to the ridges). Elsewhere, skies were generally clear with a light and variable (or light nnw) wind as a sfc ridge axis slides east across the commonwealth early this morning. NationalBlend of Models lows, ranging from the upper 20s northern mountains to upper 30s in the south, still appear on track based on latest sfc observations and LAMP guidance. Patchy low clouds will start the day across the Laurel Highlands, and are also possible over the northern mountains. SREF probability data strongly suggests this low level moisture will easily mix out by late this morning, resulting in a mostly sunny, and very mild day for the entire region. An upper shortwave diving southeast toward New England this evening will push another dying back door cold front into northeast Pa during the day today. The northeast part of the CWA will feel the greatest change, with highs potentially more than 10F cooler than Sunday`s truly springlike feel. However, based on recent performance of model guidance and an expectation of mostly sunny skies, will continue to lean toward the warmer Euro Ensemble temps, with highs ranging from the upper 40s over the mountains north of IPT, to around 60F across the southwest counties of the CWA. 850 mb temps do cool by about 2C from early today through this afternoon. So, although afternoon high temps will soar to 15-20 deg above normal, they probably will stay a good 10-12 deg F below records for today (which area: 72 at KMDT, 67 at KIPT, 62 at KAOO and 58 at KBFD). && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... Periods of mid and high clouds will stream SE across the region tonight, atop a llvl ridge axis. This ridge axis will slide to Eastern PA and Eastern New York by 12z Tuesday allowing the sfc flow to turn to the SE, while winds up around 850 mb become swrly at 15-20 kts. Should increasing cloud cover ahead of an approaching weak cold front not be as widespread or thick as currently projected, Tuesday could easily see high temps 5-8 deg F above their current forecast values in the low-mid 40s (NE), to the mid and upper 50s across the SW zones. Trimmed back timing of showers along and ahead of the aforementioned cold front until late in the afternoon or evening, and limited to the far NW through dusk. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Gradually milder temperatures will return for the extended period as no genuine cold air push is in sight. High temperatures in general will be 10 to 20 degrees above normal with min temperatures mainly above freezing. Upper ridge axis is forecast to be located east of the state Tuesday night. The weak cold frontal boundary will produce a brief period or two of showers for late Tuesday (Northwest) and over the Central and Eastern parts of PA Tuesday night into the mid morning hours of Wednesday. Clouds associated with this weak frontal boundary will help to suppress temps a bit (but they`ll still remain well above average). The flow turns back to the SW by Wednesday causing temps to rebound. The overall, large-scale pattern becomes more amplified late in the week as a system over the central plains deepens and lifts into the Great Lakes. Clouds will increase Thursday and Friday with warm front lifting through, and bringing increasing rain chances heading into the weekend. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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Predominately VFR flying expected today. Low clouds/fog restrictions still near KJST with 1000` cig at K2G9. Also area of stratus working south behind backdoor cold front with MVFR cigs possible at KIPT thru 15z. Low clouds scour out giving way to widespread VFR flying after 15z with increasing mid to high level clouds through tonight. Surface winds 330-030 shifting to 090-150 by the end of the TAF period. Outlook... Tue...Sub-VFR possible NW 1/3 late. Chance of P.M. rain showers. Wed...A.M. sub-VFR possible NW 1/3; otherwise VFR/no Sig Wx. Thu...Sub-VFR possible with chance rain showers. Fri...Sub-VFR possible with rain showers likely Friday night. LLWS probable.
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&& .CLIMATE...
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Summary of record highs from 2/18 and 2/19... Harrisburg: Record high of 69 degrees on 2/19. Previous record high was 66 degrees set back in 1997. Williamsport: Record high of 69 degrees on 2/19. Previous record high was 60 degrees set back in 1997 Altoona: Record highs of 64 degrees on 2/19 and 66 degrees on 2/18 (tie). Previous record highs were 61 in 1994 (2/19) and 66 in 1981 (2/18). Bradford: Record high of 62 degrees on 2/18. Previous record high was 56 degrees set back in 1994.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Lambert/Gartner AVIATION...Steinbugl CLIMATE...

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