Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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430 FXUS61 KCTP 251340 AFDCTP Area Forecast Discussion National Weather Service State College PA 940 AM EDT Tue Jun 25 2024 .SYNOPSIS... High pressure will drift off of the Mid Atlantic Coast by this evening. Heat will build again by Wednesday leading to a chance of thunderstorms by late in the day and Wednesday night as a cold front pushes through the state. Dry weather with comfortable humidity on Thursday and Friday will be followed by another cold front late Saturday or early Sunday of next weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Clear skies across central PA being overtaken cirrus blowoff from MCS over the central GLAKS. We`ll be dealing with these mid to high level remnants throughout the day, with greatest sky cover over the NW and thinner coverage of cirrus to the southeast. At the same time, high pressure ridge sliding across Central and Eastern PA late this morning will bring cloud filtered sunshine and light wind for much of the day followed by a gradually freshening southwest flow and some alto cu and cirrus moving in for the afternoon hours. High temps this afternoon, ranging from near 80 over the high terrain of the north and west to around 90F throughout the larger metro areas in Southeastern PA will average between 5 and 8 deg F above normal for the date. Precipitable Water values will be between 0.5 and 0.75 of an inch this morning before a rather sharp increase in deep layer moisture occurs this afternoon and evening. PWAT values will double or more (to around 1.5 inches) statewide by 02Z Wed. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... A warm front will lift northeast across the Eastern Grt Lks tonight and may spark a few showers or even a TSRA tonight, mainly over the NW Mtns. Some showers and even a rumble of thunder are also possible across the Central Ridge and Valley region of the state during the second half of the night as the instability axis over Lake Erie, sags to the SE. The increase in moisture and clouds tonight will result in low temps 12 to 14 deg F warmer than early this Tuesday morning`s. Lows will be in the mid 60s across the higher terrain of the north and west and in the upper 60s to mid 70s respectively throughout the Central Ridge and Valley region and SE part of the CWA. The aforementioned surging PWATs and falling heights ahead of an upstream cold front will bring a much better chance of widespread showers and scattered strong to potentially severe thunderstorms Wednesday afternoon/evening. There will be little break from looks like two ir 3 rounds SHRA/scattered TSRA from late Wednesday morning, through Wednesday afternoon and into Wed the aforementioned axis of CAPE becomes located over Central PA and the Susq Region. A ribbon of relatively strong low to mid level (west to southwest) winds of 50 to 55 kts, combined with moderate instability, suggests organized convection and locally severe weather is possible Wed PM. Latest ensemble plumes indicates most likely aerial average rainfall Wed will be between one half and one inch. SPC has outlined most of the CWA in a SLGT Risk area for SVR with the Northern Tier counties of the state falling within their MRGL area. High temps Wed should reach the upper 70s to low 80s across the Northern Mtns and upper 80s to low 90s respectively across the Central and SE zones. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... It gets hot again late in the week, but no long-term records (except perhaps maxi-mins Sat night) should be challenged. Relief/precip/storms come from a cold front in the middle of the weekend (timing subject to change slightly). Prev... Showers and storms will gradually exit to the the Southeast counties of PA Wednesday night as high pressure builds in. The midweek cold front will reset the cycle similar to what today`s cold front will do and usher in a similar stretch as Monday & Tuesday. Thursday and Friday will consist of about 48 hours of lower dewpoints, temperatures closer to average for this time of year, and plenty of sunshine. Afternoon highs in the 70s and 80s, overnight lows in the 50s and 60s (perhaps even upper 40s in the northern mountains Friday morning), and dewpoints below 60F will feel especially good with the persistent stretch of heat. As high pressure shifts to the east on Friday, southerly flow will support increasing temperatures and moisture into the weekend. The chance for showers and storms will also ramp up Saturday as a warm front lifts across the region. By Sunday, a trailing cold front will bring additional showers and thunderstorms and usher in another cooler stretch for the start of July. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... Mainly VFR conds continue through the TAF period. Any patchy fog that is present across the northwest will dissipate by 13Z. High clouds will begin spreading into the area from the west during the late morning. The clouds will begin to lower into the evening across the west and MVFR ceilings likely develop at BFD after 00Z as showers and potentially a thunderstorm or two left over from convection to our west approach the region. There is low confidence in how much precipitation occurs overnight as it will be dependent on the evolution of convection to our west during the day today. Model soundings support ceilings dropping to IFR at BFD by 08Z and LIFR ceilings appear possible. These lower ceilings increase in coverage across the region, with all sites except MDT and LNS likely seeing MVFR ceilings by sunrise. A west- southwesterly low level jet moves in to the northwest as well and will lead to a period of LLWS as winds at 2000 feet increase to around 45 knots. Confidence is highest that BFD see LLWS, while it appears more marginal at other airfields. Outlook... Tue...VFR, no sig wx expected. Wed...Restrictions possible in TSRA. Thu...AM SHRA/TSRA with restrictions possible, drying out late. Fri...Mainly VFR. Sat...Restrictions possible in TSRA/SHRA. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert/DeVoir NEAR TERM...Lambert/DeVoir/Dangelo SHORT TERM...Lambert LONG TERM...Banghoff AVIATION...Colbert/Bauco