Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 172311 AFDCTP Area Forecast Discussion National Weather Service State College PA 711 PM EDT Tue Apr 17 2018 .SYNOPSIS... An upper level disturbance will will swing though the region today and this evening. Developing low pressure in the Mississippi Valley will track east across Pennsylvania Wednesday night and early Thursday, then high pressure will work into the region late in the week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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23Z Radar has snow showers continuing to move through south central region. Have issued continued SPS`s with reduced visibilities as the lines of snow showers have moved through the south. Decent shear through the mid levels along with a LLJ at 850mb coupled with the trough providing instability is the main forcing for this system. A few lightning strikes have even been recorded in Altoona. A coating is expected through most of the Laurels with higher amounts, in the one to two range in the northwest mountains. The biggest travel concern remains the reduction of visibilities and while the temperatures are slowing dropping the ground is still wet and warm. As the evening continues, the lack of diurnal heating, along with the trough moving to the east and the corresponding LLJ which will all but end most of the showers. Some lingering showers through the NW due to orographic lift remains probable. The shortwave will move off to our east this evening with rising heights aloft and drier air around 01Z. Despite a very cold April to date, the growing season has technically begun over the lower Susq Valley. With lows around freezing or even a few deg colder, we have issued a Freeze Warning for the counties from Franklin east to Lancaster and north to include Dauphin and Lebanon. Elsewhere the overnight lows will average about 25-30 deg.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... A brief period of fair weather can be expected for most of Wednesday, as a low amplitude ridge races east. The return of partly to mostly skies will result in milder temperatures, but still below average. Clouds will increasing late in the day, with the chance of showers reaching my far western counties by evening, as yet another shortwave takes aim at PA. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... Passage of low pressure will likely bring a period of rain Wednesday night, followed by snow showers over the mountains into Thursday as upper trough comes through. We don`t expect any significant accumulations, but as we enter mid April, the prospects for snow are less than welcome. Past Thursday we foresee a break of dry weather into early next weekend as energy reloads over the southwestern U.S. allowing weak upper ridging to build over the eastern part of the country. Yet another upper low in this busy pattern looks to drop into the deep south toward the end of the period. This may spread some precipitation northward toward our region for the beginning of next week. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... A cold gusty WNW flow with MVFR/VFR and frequent snow showers across the western 1/3-1/2 of the airspace will continue into the evening hours before drier air brings improving conditions. A few heavier snow squalls through evening will bring brief reductions in visibility to near airfield minimums, especially at BFD/JST. Low VFR should prevail across the southeast 1/3 of the airspace with brief restrictions possible in passing snow/rain showers. Winds from 260-290 degrees 10-20kts with gusts 20-30kts will continue overnight. Snow showers will taper off this evening with mainly dry conditions developing. Any sub VFR conditions at BFD will improve early, otherwise Wednesday will see widespread VFR with a diminishing wind. Another period of rain/snow is expected Wednesday night and Thursday. Outlook... Fri-Sat...No sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... Freeze Warning from 3 AM to 8 AM EDT Wednesday for PAZ036-057- 059-063>066. && $$ SYNOPSIS...La Corte NEAR TERM...Ceru SHORT TERM...La Corte LONG TERM...Gartner AVIATION...La Corte is the U.S. government's official web portal to all federal, state and local government web resources and services.