Surface cold front stationed west of the region allowed for ample heating across the Susquehanna Valley during the afternoon and evening hours of August 13, 2025. Marginal shear and ample instability allowed for convection to begin firing, with strong-to-marginally severe thunderstorms to occur across southeastern Pennsylvania.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CTP wrote it up.
Surface cold front stationed west of the region allowed for ample heating across the Susquehanna Valley during the afternoon and evening hours of August 13, 2025. Marginal shear and ample instability allowed for convection to begin firing, with strong-to-marginally severe thunderstorms to occur across southeastern Pennsylvania. An isolated instance of tree damage was observed in Lancaster County. Precipitable water values ranging generally between 1.50 and 2.00 allowed for efficient rainfall in thunderstorms across York and Lancaster Counties, with a basement taking on water in southern York County.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS State College, PA wrote its last area forecast discussion before the first event at Aug 13, 1:45 PM EST, 1 hour 25 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 245 PM EDT Wed Aug 13 2025 .SYNOPSIS... * Cold front moves in from the north tonight and slows/stalls over the state tonight. Storms this afternoon and evening may produce heavy rain. * Afternoon thunderstorms are possible Thursday, mainly S * Dry Friday with low humidity before PM thunderstorms return Saturday && .NEAR TERM /THROUGH TONIGHT/... Monitoring two distinct clusters of storms as they traverse the Commonwealth this afternoon: the first is in northeast PA ahead of a surface vort max. Most of the storms there have cleared the CWA and are moving along nicely. The second is a complex of very slow moving storms that has drifted across the Laurel Highlands and south central mountains today, dropping isolated rainfall amounts over 2 inches. A Flash Flood Warning was issued for northern Bedford, southern Huntingdon, and northern Fulton Counties until 445PM. PWAT in the 1.5-1.8" range today and little shear makes the possibility of heavy downpours a legitimate threat. HREF PMMs paint bullseyes of 3"+ across southeast PA, which led to a SLGT risk upgrade for excessive rainfall at midday. Have mentioned +RA possible in the wx grids. Dry antecedent conditions (over the past two weeks) limit the threat of flooding considerably, but too much rain in urbanized areas could be problematic. Shear is low (20-30kts), so the risk for severe is not overly concerning, but some water loaded downbursts cannot be ruled out, especially as storms move into an increasingly unstable environment. Highs this afternoon will range from the upper 70s across the north and west to low 90s in the southeast. Td in the L-M70s could push AppT close to 100 in the Lower Susquehanna Valley, but the arrival of showers/storms/clouds should limit the duration of any 100F heat indices and therefore preclude a Heat Advisory issuance. Convection should wane after sunset tonight with the loss of daytime heating and eastward propagation of an upper trough/surface vort max. A few isolated showers are possible overnight as a cold front moves into the region. The cold front should get into the central mtns tonight and slow down considerably. Clear skies should support widespread valley fog by daybreak as lows fall into the upper 50s in the northwest mountains and stay in the upper 70s in southeast PA. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... The cold front will continue to move slowly southeast during the day on Thursday. That will leave a lifting mechanism in place for the central and srn zones. The higher (30-40) PoPs should be in the SE half with the NW staying dry as the dewpoints there drop into the M50s - even while Lancaster Co holds onto dewpoints in the L70s. Coverage of storms should be isolated to scattered and the threat for severe weather or flash flooding seems quite low. More fog possible Thursday night, even as lower dewpoints move into northwest PA. Friday morning will be the coolest of this stretch as high pressure moves in and radiational cooling supports lows perhaps starting with a 4 in the coldest parts of northwest PA. Dewpoints will stay up in the southeast (mid 60s), as the true drier/cooler airmass fails to truly clear the Mason-Dixon Line. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Lowering humidity on Friday will bring some minor/temporary relief to summertime humidity, but overall there is no end to our run of hot/above normal temperatures through mid August. Minor plume of moisture along a weak trough will allow for a few diurnal TSRA Saturday along the spine of the Appalachians. A cold front then moves down into the area later Sunday, and should have scattered to numerous SHRA/TSRA in advance of and along the front. The sfc high behind that front should be strong enough to push the front to the srn border, but it could linger nearby. That would lead to isold SHRA/TSRA into mid-week. So we can't quite shake 20-30 PoPs for next week. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... Scattered thunderstorms have developed and will continue through the rest of the afternoon. Any thunderstorms that move directly over any airfields will produce reductions in visibility and gusty winds. There is some uncertainty still as to how much convection develops behind ongoing convection, so adjustments to the TAFs will likely be needed. Showers and storms come to an end late this evening and skies may briefly clear our before fog and low clouds develop across much of the region. IFR conditions appear most likely at BFD, JST, UNV, and LNS, though all sites may see IFR cigs/visby at some point tonight. Fog and low clouds will gradually dissipate after sunrise and VFR conditions will return by 15Z. Outlook... Thu...Lingering showers/and a few PM storms possible across the southern airspace. Some valley fog is possible through about 12Z today, and a tempo group has been included to highlight this at sites were confidence in fog formation is highest. Fri...AM fog possible; otherwise VFR. Sat...Mainly VFR. Sun...Mainly VFR, but chance of a shower or storm north late. Mon...Chance of a shower early, then clearing. && .CLIMATE... It's been a very dry period over the last 2 weeks or so. Here are the precipitation totals and rankings for the first 12 days of August (month to date): MDT: T (2nd driest); last measurable rain 7/31 IPT: 0.00" (driest); last measurable rain 7/30 AOO: 0.01" (2nd driest); last measurable rain 8/6 BFD: 0.09" (T3rd driest); last measurable rain 8/6 STC: T (tied-driest); last measurable rain 7/28 && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Dangelo/Banghoff NEAR TERM...Dangelo/Banghoff SHORT TERM...Dangelo/Banghoff LONG TERM...Dangelo/Steinbugl AVIATION...Lambert/Bauco CLIMATE...Steinbugl
Hazardous Weather Outlook National Weather Service State College PA 711 AM EDT Wed Aug 13 2025 PAZ004>006-010>012-017-018-037-041-042-045-046-141115- Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield- Northern Centre-Tioga-Northern Lycoming-Sullivan-Southern Clinton- Southern Lycoming- 711 AM EDT Wed Aug 13 2025 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Thunderstorms with very heavy rain are possible today and early tonight. The heavy rain may cause isolated incidents of flooding. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ019-024>028-033>036-049>053-056>059-063>066-141115- Southern Centre-Cambria-Blair-Huntingdon-Mifflin-Juniata-Somerset- Bedford-Fulton-Franklin-Union-Snyder-Montour-Northumberland-Columbia- Perry-Dauphin-Schuylkill-Lebanon-Cumberland-Adams-York-Lancaster- 711 AM EDT Wed Aug 13 2025 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Thunderstorms with very heavy rain are possible today and early tonight. The heavy rain may cause isolated incidents of flooding. A thunderstorm or two could make gusty winds, as well. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather.
The Dover AFB radar (KDOX), 157 km away, was scanning. The volume nearest the first event began at 20:11 UTC.
1 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm, producing wind gusts estimated near 60 mph, knocked a tree down onto the roadway near the intersection of Butter Road and Hunsicker Road north of Zooks Corner.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2025Every state in 2025This day in weather historyWarnings in Pennsylvania, August 2025
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1273315.