Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 222248 AFDCTP Area Forecast Discussion National Weather Service State College PA 648 PM EDT Tue May 22 2018 .SYNOPSIS... Low pressure will track down the St Lawrence River Valley, dragging a cold front through the region overnight. High pressure will build southeast into the region for the second half of the week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Low level jet and associated batch of steady overrunning rain has shifted northeast of the forecast area as of 2045Z. Meanwhile, surface analysis shows a north to south oriented surface warm front bisecting the state, running just east of a line from KELZ to KUNV and KHGR. Breaks of sun within the warm sector is resulting in rising temps and developing instability across the western half of the forecast area. Radar at 2045Z shows convection starting to fire along cold front over northwest Pa and latest HRRR and HREFV2 indicate this band of thunderstorms will push southeast into our western counties this evening. The Allegheny Plateau stands the best chance of some strong to locally severe thunderstorms this evening, with a weakening trend to occur as convection moves into a more stable air mass further east. Much of the area is likely to experience a round or two of showers/storms between 22Z-06Z associated with cold front moving into the area. Drier air and a diminishing chance of showers is expected late tonight, as cold front pushes south of the area. With skies remaining cloudy, lows will only drop back into the 50s to lower 60s, which will be much warmer than normal. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... A few showers may still linger over my far SERN zones early Wednesday, but drier air on a freshening northerly breeze will usher in much improved conditions as the day progresses. Highs will range through the 70s with comfortable humidity. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... Look for high pressure and dry weather Wednesday night through Friday with seasonable morning lows and warm afternoons. Saturday is trending drier and will probably be the warmest day of the holiday weekend with most locations in the 80s. 12Z mid to long range models continue to show an approach trough that will swing through the great lakes. With streaming southwesterly moisture and max temps in the 80s, Saturday afternoon could see some convection. Sunday into Memorial day could continue to see more unsettled, humid and a little cooler weather. While there will be pops in the forecast, still uncertain exactly how wet things will turn out. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/...
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MVFR and localized IFR Cigs will continue through at least the first half of tonight (perhaps until shortly after sunrise Wed) across the region near, and to the east of the Susquehanna Valley under light easterly llvl flow near the sfc. Mainly VFR will dominate elsewhere, with isolated to sctd generally brief MVFR cigs and vsbys in SHRA/TSRA along and ahead of a cold front that`s currently pushing SE across Lake Erie. The SHRA and TSRA will weaken substantially across the eastern half of PA as they encounter the cooler and more stable air. As the NW breeze develops in the wake of the cold front, there could a several hour (or longer) period of low cigs from moist upslope flow (03-12Z Wed) prior to more significant drying advecting into the area and enhanced by deeper vertical mixing beginning later Wednesday morning. The cold frontal passage is timed to occur across the Lower Susq Valley around or shortly before daybreak Wednesday, after which any low clouds will gradually lift with clearing out substantially by the early afternoon INVOF KIPT...KMDT and KLNS. Mainly VFR is expected a few to several hours earlier (i.e. Late Wed morning) across the NW and Central Mtns. NW winds will gust into the upper teens to lower 20 KT range during the late morning and afternoon hours Wed. Outlook... Wed...AM MVFR/IFR becoming widespread VFR by mid day. Thu-Fri...VFR/No sig wx expected. Sat-Sun...Warm and humid mainly VFR with scattered showers/thunderstorms.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...Fitzgerald/La Corte SHORT TERM...La Corte LONG TERM...Ross AVIATION...Lambert/ La Corte is the U.S. government's official web portal to all federal, state and local government web resources and services.