Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 190418 AFDCTP Area Forecast Discussion National Weather Service State College PA 1218 AM EDT Wed Oct 19 2016 .SYNOPSIS... Southwest flow ahead of a cold front will keep much above normal temperatures over the region right through midweek. Cooler air will follow the cold frontal passage Wednesday. Unsettled conditions will redevelop for the end of the week as a series of low pressure areas ripple up along the trailing cold front. Breezy and colder weather will move in for the weekend. && .NEAR TERM /THROUGH TODAY/... A cold front over the eastern Great Lakes this evening will sag south overnight...with line of showers ahead of the front now entering northwest PA. Guidance continues to dissipate qpf as moisture convergence wanes later this not much in the way of measurable pcpn is expected south of I-80. Main impact of the front`s arrival will be to flatten the thermal ridge...which will lead to slightly cooler overnight mins across the north and central areas...and several degrees cooler maxes on Wednesday. Mins tonight will range from the mid 50s northwest to the lower to middle 60s south...still well above normal. && .SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/... Wednesday will still be very mild with almost no additional push of cooler air behind the diffuse-dying cold front. A blend of models support the potential for a stray shower over western and southern areas...with maxes still well above normal for this time of year. Expect highs to range from the upper 60s north through the 70s Laurel Highlands through the Central Mountains to the lower 80s south. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... The 18/12Z guidance has come into good agreement on a split-flow upper trough amplifying over the Eastern U.S. through the end of the week and into the weekend, with 500mb height anomalies reaching -2SD by 22/12Z. This will allow low pressure to develop and track northeast along a stalled frontal zone over the OH Valley on Thursday and into west-central PA/NY Thursday night into Friday. Significant backing of mid level heights and upper trough orientation going negative tilt should slow the system progression and support broad area of soaking rain along/behind the front. Favorable right entrance region jet dynamics and above normal moisture should also aid in producing moderate to locally heavy rainfall amounts. Followed WPC guidance for the most part with QPF amounts derived largely from GFS/EC blend. This resulted in a stripe of 1.5-2.5 inches for 36-hour total ending 00Z Saturday across the northwest 1/3 of the area. Low pressure developing northeast of the Turks and Caicos (currently being monitored by NHC) is forecast to track northwest and then north ahead of the deep layer trough approaching the East Coast by the end of the week. The models show some differences concerning the possible interaction between this low and the aforementioned surface low with the CMC the most bullish. The full range of guidance suggests odds are slightly higher for the two system to remain largely separated with eventual consolidation and further deepening likely by the time the system reaches northern New England by early Saturday. This will result in a colder and brisk/gusty northwest flow pattern with some potential for wrap-around/deformation precipitation giving way to showery regime focused downwind of Lake Erie and over the higher terrain of the Alleghenies/Laurel Highlands. Surface-850mb temps will be marginally cold enough to support rain/snow showers especially Saturday night over the NW mtns but no accumulation is expected. GFS/EC show a fast-moving low diving through the Great Lakes into early next week. This system has low predictability given it weak state embedded within a progressive WNW flow aloft. Temperatures start off very mild for the later half of October but trend noticeably colder/below normal by the weekend. The roller-coaster up and down swing in temperatures is not uncommon for this time of year and will only continue as the calendar turns towards winter. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
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Front and associated showers moving into northwest Pennsylvania, with MVFR conditions at KBFD at 03z. Lowering clouds associated with the approaching front will continue to progress across western and central airfields tonight, but with shower activity expected to dwindle as the front moves into the southeast. This should limit flying restrictions over the southern and eastern airspaces. A larger scale rain event will impact the area late week into the weekend. Outlook... Tonight...Reductions western and central airfields. Reductions into IFR or LIFR possible in the mountains, with fog restrictions at KIPT. Wed...Morning reductions NW half and potentially into central mtns. Thu-Fri...Reductions likely area-wide. Scattered showers SE, period of rain elsewhere. Sat...Restrictions NW. Sct showers NW. Breezy. Sun...No restrictions.
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&& .CLIMATE... Daily record maximum temperatures are in jeopardy for 10/18. Here are the current records: Harrisburg: 82 in 1908 (new record set 83F at 2pm) Williamsport: 82 in 1964 (new record set 84F at 3pm) Altoona: 81 in 1998 Bradford: 75 in 1963 State College:83 in 1938* *10/18 high will be officially recorded on 10/19 (7am-7am COOP) report so used 10/19 for record purposes. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir NEAR TERM...Gartner SHORT TERM...DeVoir/Gartner LONG TERM...Steinbugl AVIATION...Jung CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.