Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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307 FXUS61 KCTP 081921 AFDCTP Area Forecast Discussion National Weather Service State College PA 321 PM EDT Wed May 8 2024 .SYNOPSIS... - A mainly dry cold front pushing through the Susquehanna Valley this afternoon will stall out just south of PA tonight. - A strong wave of low pressure will move across southern PA Thursday evening bringing periods of rain, with some potentially gusty thunderstorms over the southwest third of the state. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Surface cold front, marked mostly by a moderately sharp dewpoint drop, extended from the Poconos of NEPA to the Lower Susq Valley at 1830Z. Negative LLVL Theta-E advection and increasing wind/shear aloft will continue to negate the chance for any cu to develop vertical enough to produce precip along or ahead of this boundary. For the rest of this afternoon, look for good weather for most outdoor activities with abundant sunshine and above normal high temps by around 10 deg F. However, a gusty West-Northwest wind (between 30-35KTS) will create good kite-flying weather, but challenging conditions for the gold and Frisbee football courses. Temps are right around their fcst highs, varying from mainly the mid 70s across the higher terrain of the north and west to the mid 80s throughout the Southern Valleys and Lower Susq Region. Sfc dewpoints have plunged to the U30s to L40s across the Northern Mtns in the wake of the aforementioned front and enhanced by deep subsidence beneath the right exit region of a 130 kt upper jet over Lake Erie. West winds and gusts will steadily decrease around and shortly after sunset before veering around to a lighter NW then northerly direction between midnight and daybreak. After an initially clear sky, high clouds will increase from the SW. Min temps will dip into the mid 40s across the north and mid to upper 50s in the south. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Frontal boundary stalls near or just to the south of the Mason/Dixon line late tonight/Thursday morning, and model ensembles indicate a consensus sfc low track across SW PA then likely across the Mason Dixon line or the Panhandles of MD and WVA. SFC and elevated instability is minimal for all but Somerset County Thursday. Blended in the colder members of the NBM and NAM based on the timing of increasing clouds later Wed night/early Thursday and the showers/periods of steadier rain spreading north and cutting off heating in the morning. A flat/no-diurnal T curve is strongly in play for Thursday. Max temps could struggle to reach 60 across much of Central and northern PA and may hold in the mid 50s over the N Mtns. Periods of chilly rain continue Thursday afternoon and night with low clouds/fog shrouding the ridges. Storm total rainfall for Thursday into early Friday are between 0.50 and 1.00 inch with some locally higher amounts possible. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... The aforementioned low moves off the coast on Friday and will allow for relatively cool temperatures across central PA with lingering showers as the unsettled pattern continues into the weekend with an upper low crossing the region. The best chances of precipitation tapering off will be in the overnight Saturday morning period with chances increasing into the latter half of the weekend. Drier period will continue into the first part of next week, the rest of the long term period, as upper level ridging builds/moves across the eastern U.S. thanks to long wave troffing being reconstituted across the Plains/eastern Rockies. This will likely mean more rounds of strong to severe thunderstorms for the Plains, but a more settled pattern and milder temps in the East, at least for few days. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... A cold front from the Poconos to the Lower Susq Valley this afternoon will move southeast to the Mason Dixon line tonight then stall out there through Thursday. A drier westerly flow behind the front will maintain the current, widespread VFR conditions for the rest of today and tonight. Winds will generally gust in the 20-30KT range behind the cold front, but a few gusts in the mid-upper 30KT range are possible. Periods of rain with lowering CIGS (and a few T-storms across SW PA) will impact flight operations beginning during the mid morning hours Thursday and continuing through Thursday night (and likely Friday) as low pressure at the surface and aloft moves east from the Ohio Valley. Outlook... Thu/Thu night...Periods of rain/low cigs possible, mainly from Thu afternoon on. Fri...Low cigs/drizzle possible, especially in the morning. Sat...PM showers/low cigs possible, mainly W Mtns. Sun...AM low cigs possible W Mtns. Sct afternoon showers/brief vis reductions possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Gartner/NPB AVIATION...Lambert