Area Forecast Discussion
Issued by NWS State College, PA

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035 FXUS61 KCTP 010152 AFDCTP Area Forecast Discussion National Weather Service State College PA 952 PM EDT Mon Jun 30 2025 .SYNOPSIS...
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* Stormy pattern continues tonight and tomorrow as a warm front (today), then cold front (tomorrow) pushes through the region, bringing a 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 * Trending warmer and more muggy again early next week.
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&& .NEAR TERM /UNTIL 8 AM TUESDAY MORNING/...
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Scattered to numerous showers and thunderstorms continue to move through Central PA tonight as very high PWAT air produces efficient downpours and locally strong winds. Rainfall amounts as high as 4 to 5 inches have been observed in parts of Lancaster and Lebanon Counties where multiple rounds of storms have produced flooding. A slow moving warm front is draped across northeast PA and was a focus for thunderstorm activity this afternoon and evening. As it continues to drift northeast, broad southerly flow underneath an amplifying mid-level trough continues to generate locally heavy downpours and locally strong wind gusts. With the loss of daytime heating, cold pools should begin to takeover by 10 or 11pm and storms will wane before midnight, thus ending the threat for severe weather and flash flooding. 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. It will be quite warm and muggy with temps slowly slipping through the 70s before reaching a low in the mid to upper 60s across the northern and western mtns and 70-75 in the central and southern valleys.
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&& .SHORT TERM /8 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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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. SPC continues a Slight Risk of severe weather, primarily southeast of the I-81 corridor. Storm motions should be a bit quicker tomorrow, so the risk for flooding will be comparatively lower/more isolated compared to Monday. That being said, isolated totals of 2-3"+ in portions of the Lower Susquehanna Valley that got hit hard on Monday could spell trouble. A Flood Watch will likely be needed if the potential for heavy rainfall in those areas continues to look likely. Drier air will begin advecting into central PA late Tuesday into Tuesday night with dewpoints dropping well into the 60s. Clearing skies behind the front will likely support fog formation, with the highest risk of reduced visibility occurring west of I-99 and in the valleys northeast of Harrisburg up into the Wilkes-Barre/Scranton area. Lows by Wednesday morning will range from the low 70s in southeast PA (where cloud cover will hang on the longest) to the upper 50s in the northwest mountains.
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&& .LONG TERM /WEDNESDAY THROUGH MONDAY/...
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In the wake of the cold front passing east of the area by Wednesday morning, high pressure begins to build southwest of the region, providing fair weather for the middle of the week and into the weekend. Best chances for precipitation through Saturday will remain due to a cold frontal passage across the northern half of Pennsylvania. Cold front remains relatively moisture-starved; however, generally think forcing will be enough to cause a shower and afternoon/evening thunderstorm. The biggest feature of the post-frontal airmass will be much lower dewpoints and refreshing nights/mornings. There is high confidence in lows dropping into the 50s and low 60s Thursday and Friday nights, which will be a significant and welcome change from the long-duration heat/humidity we have experienced over the past few weeks. Independence Day activities should be under fair skies, comfortable temperatures, and pleasant northwest winds. Low pressure approaching the Great Lakes by Sunday morning will bring about increasing chances for precipitation for the second half of the weekend and into the beginning of next week.
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&& .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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Scattered showers and thunderstorms continue late this evening with periodic restrictions expected. The coverage and intensity of showers should taper off by 04Z with only lingering light showers possible overnight. The overnight forecast is a little tricky - a mix of conditions are expected with a potpourri of the following restrictions possible: visibility reductions in scattered showers/storms; visibility and perhaps ceiling restrictions in patchy dense fog, and ceiling restrictions in low clouds. During the day on Tuesday, more showers and storms are expected ahead of a cold front that will traverse the region during the afternoon and evening. Have tried to time out the best window for thunderstorms potential at all TAF sites, with the heaviest rain/strongest storms likely at MDT and LNS. Outlook... Tuesday Night...Clearing skies with patchy to widespread fog possible. Wed...AM fog, then VFR. Thu...Primarily VFR; stray PM shower/t-storm possible. Fri-Sat...AM fog possible; otherwise VFR.
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&& .CTP WATCHES/WARNINGS/ADVISORIES...
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None.
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&& $$ SYNOPSIS...Lambert/Banghoff NEAR TERM...Lambert/Banghoff SHORT TERM...Lambert/Banghoff LONG TERM...Banghoff/NPB AVIATION...Lambert/Martin