Area Forecast Discussion
Issued by NWS State College, PA

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811 FXUS61 KCTP 070803 AFDCTP Area Forecast Discussion National Weather Service State College PA 403 AM EDT Mon Jul 7 2025 .SYNOPSIS...
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* Hot and Humid today with thunderstorm downpours concentrated in the northwest Alleghenies and near the I-95 corridor * Scattered T-storms will be focused primarily over the southeastern half of the Commonwealth Tuesday afternoon * Seasonably warm and muggy for the rest of the week with scattered thunderstorms during the afternoon and evening
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&& .NEAR TERM /THROUGH TONIGHT/...
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A moist southeast flow ahead of the circulation associated with the remnants of Chantal will bring low clouds/ridgetop fog and perhaps an isolated rain shower to south central PA early this morning. The increasing cloud cover and low level moisture will make for a very warm/muggy start to the day with sunrise temps 65-75F. Early cloud cover should peel off the east northeast with partly to mostly sunny skies across the majority of central PA to start the afternoon; the exception will be the far southeast zones. Today will be hot and humid with max temps in the mid 80s to low 90s or 5-10F above the historical average for early July. Max HX values approach 100 in many of the central and eastern valleys. There are two areas to focus on today based on hires ensemble guidance and severe t-storm/excessive rainfall outlooks from SPC and WPC: 1. Northwest Alleghenies: Widely scattered thunderstorms are expected to develop this afternoon along/ahead of a slow-moving cold front pushing southeastward from the Lower Great Lakes. Around 30 kt of effective shear amid a diurnally destabilizing boundary layer will allow for loosely organized multicell clusters capable of producing isolated wind damage (svr tstm risk level 1 out of 5 or MRGL). HREF 3hr QPF PMM signal also highlights a locally heavy rain threat across this area (peaking 18-21Z downwind of Lake Erie) with >1.5" pwats supporting some isolated point amounts of 2+ inches possible. 2. The far eastern portion of the Lower Susquehanna Valley: Isolated flash flood concerns will extend along the I95 corridor as tropical moisture associated with the remnants of Chantal track from southern VA over the DelMarVA into southern NJ by 00Z Tue. PWATs >2 inches and well defined mid level vort max will drive potential for locally heavy to excessive rainfall which appears to align with a convergence axis over southeast PA. Although higher probs for heavy rain are positioned just to the east of the Lower Susq Valley in the PHI/LWX CWAs (I-95), it is close enough to monitor for a possible short-fused FF watch. Coverage of showers fades overnight with a good signal for post frontal low clouds over the western mtns and areas of fog across the central and eastern valleys. Another warm and muggy night in most locations with low temps in the 65-75F range.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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Max temps drop 5-10 degrees behind the front over the western 1/2 of the CWA on Tuesday. The latest guidance shows the front stalling out or becoming quasi stationary over CPA by 00Z Wed. There will be marginal risk of severe storms and excessive rainfall mainly for areas to the southeast of the frontal zone where there will be plenty of MLCAPE and 70+ dewpoints. Tall or thin profiles suggest more of a +RA vs. severe storm threat, but a few stronger multicellular cores may be capable of producing an isolated damaging wind gust. There also remains some concern for max HX values to reach or exceed the century mark in the LSV Tuesday afternoon. A heat advy may be needed; for now we coordinated with PHI to not include any of the Lehigh/Lower Susq zones but will continue to highlight in the HWO. Best odds for a thunderstorm on Wednesday remains along the MD line where the best moisture/instability overlay will exist. At this time, t-storms are expected to be non-severe with heavy rain risk shifting to the south of the Mason Dixon line. Max/min temps remain seasonably warm for early/mid July.
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&& .LONG TERM /THURSDAY THROUGH SUNDAY/...
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PoPs rise again Thursday with the approach of another shortwave trough. The forecast for Friday and the weekend is more uncertain, with some guidance suggesting a break in the unsettled pattern, and others suggesting active weather continues. An active pattern would favor continue heat/humidity while a quieter pattern could support the intrusion of lower dewpoints and more refreshing conditions.
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&& .AVIATION /07Z MONDAY THROUGH FRIDAY/... VFR prevails through late this evening with nothing but a deck of high cirrus clouds increasing in coverage from south to north. Expect winds to become light southerly or light and variable at most TAF sites. Low level moisture creeping up the east coast will likely bring a deck of MVFR/IFR clouds into the Susq Valley terminals of IPT/LNS/MDT after 08-10z tonight. Restrictions may make it as far west as UNV and AOO, but confidence remains low enough to maintain VFR conditions there. IFR is most likely at MDT and LNS in the 10-12Z window with improvement after daybreak. A few showers and thunderstorms may affect MDT/LNS in the morning as tropical moisture moves into the air space. Then, scattered showers and storms will move across Central PA along a cold front during the afternoon and evening. Outlook... Tue...Restrictions in MVFR cloud (northwest) and scattered showers/storms (southeast). Wed...Best chance for storms and restrictions in southern PA. Thu-Fri...Potential for showers and thunderstorms, mainly aftn/eve. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM...Steinbugl LONG TERM...Lambert/Banghoff AVIATION...Banghoff/Gartner