Area Forecast Discussion
Issued by NWS State College, PA

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250 FXUS61 KCTP 301113 AFDCTP Area Forecast Discussion National Weather Service State College PA 713 AM EDT Mon Jun 30 2025 .SYNOPSIS... * Stormy pattern resumes today and tomorrow with a renewed risk of strong to severe storms and locally heavy downpours * Drier/less humid/more comfortable conditions are likely from mid to late week with high confidence of nice weather on Independence Day && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Patchy valley fog not a significant concern this morning given mid-high clouds over central PA. Healthy moisture return will continue this morning with precipitable water values currently breaching the 1.5 inch mark across south central PA as a warm front surges north. This influx of moisture will occur downstream of an amplifying mid-upper trough moving into the Upper Midwest and western Great Lakes. Numerous showers and thunderstorms are expected beginning early this afternoon and lasting through this evening as shortwave energy supplies large scale forcing for ascent. Given the presence of weak/modest vertical wind shear, a few of the storms could become strong to locally severe. Strong boundary-layer heating is expected with 2000+ J/kg of tall/thin SBCAPE) amid relatively weak effective shear values of 25-30 knots. This environment will support the potential for wet downbursts and damaging wind gusts. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... Storms will continue into this evening with cold pools taking over and bringing an end to the widespread shower activity after dark. Given the refuel of surface water from Monday`s rain and sultry conditions tonight, expect fog tonight into Tuesday morning, especially where low clouds can break. The aforementioned mid-level trough will shift east from the Great Lakes to the Northeast on Tuesday. Moderate mid-level flow will overspread much of the region, including placing central PA in the right entrance region of an upper-level jet. At the surface, a cool front will move east across PA and will be the primary focus for severe thunderstorm potential Tuesday afternoon/evening. Stronger shear profiles will be present on Tuesday and this may result in greater storm organization/intensity including the potential for a few supercells capable of producing large hail and damaging wind gusts. Storms should eventually congeal into a more solid line as the front makes closer approach, maintaining a damaging wind threat into the Lower Susquehanna Valley. Drier air will begin advecting into central PA late Tuesday into Tuesday night with dewpoints dropping well into the 60s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... * Expect a drier and more comfortable stretch of weather for Wed-Sat. * Increasing confidence in nice/dry weather on July 4th. There is growing confidence in a drier and more comfortable stretch of weather from midweek into the first weekend of July. Expanding on the drier/comfortable stretch, we are talking specifically about: 1) little to no rainfall and 2) noticeably lower heat and humidity. A moisture-starved cold front will provide the "best" chance of rain Thursday PM, but overall we expect the majority of the time to be dry during the Wed-Sat period. Max/min temps will be close to the historical average during the first week of July. There are signals for heat and humidity to ramp upward by the end of the weekend. && .AVIATION /11Z MONDAY THROUGH FRIDAY/...
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For the 12Z TAF package, may add fog in at AOO for an hour or so. Otherwise fcst on track. More information below. Lone shower in south central PA died shortly after Midnight. However the edge of the higher dewpts not much further south and also to our west, once one gets into OH. NAM shows showers and storms will try to work in from both the southeast and west toward mid to late aft. Highest chc of thunder will be mainly west of a BFD, JST line. Did not make any big changes to the earlier TAF fcst. CIGS likely to be rather high with showers and storms this afternoon, but would would lower down by mid to late evening. Earlier discussion below. Predominantly VFR conds are expected to continue overnight, although there is low confidence that some spots could see the development of fog/low clouds during the predawn hours. High and mid level clouds may help to limit fog development. Scattered SHRA/TSRA impacts are expected Monday afternoon and evening, and have added a PROB30 group to several TAF sites Mon aftn/eve to highlight the potential for brief restrictions. Outlook... Tue...PM showers & t-storms likely; areas of fog & low clouds as well. Wed...AM fog, then VFR. Thu...Primarily VFR; stray PM shower/t-storm possible. Fri...AM fog possible; otherwise VFR.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Guseman/Steinbugl/Bowen NEAR TERM...Guseman/Steinbugl/Bowen SHORT TERM...Guseman/Steinbugl LONG TERM...Steinbugl/Evanego AVIATION...Martin/Evanego