Isolated showers and storms developed along a stalled frontal boundary over southern PA during the afternoon and evening hours of July 28, 2021. One of these storms produced multiple wind damage reports as it drifted south-southeastward across York County.
Every event with a place to put it. Tap one for its entry below.
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.
Isolated showers and storms developed along a stalled frontal boundary over southern PA during the afternoon and evening hours of July 28, 2021. One of these storms produced multiple wind damage reports as it drifted south-southeastward across 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 Jul 28, 2:42 PM EST, 1 hour 8 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 342 PM EDT Wed Jul 28 2021 .SYNOPSIS... Isolated strong storms are possible this afternoon across the southwest portion of central PA and may produce locally damaging wind gusts. The risk of severe storms has increased on Thursday with a wind damage and isolated tornado threat possible. A northwest breeze will bring cooler and less humid air into the area on Friday which will set the stage for a beautiful start to the weekend. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... The forecast area will be split from northwest to southeast this evening as a frontal boundary is draped from roughly Erie to Philadelphia. Along and to the southwest of this line, a few showers have developed and will track to the southeast through sunset. Severe potential is lower this evening but will monitor for any potential strong cells. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Better model agreement on the evolution of upstream convection combined with new model data has resulted in an increased risk of severe storms on Thursday; SPC has expanded the SLGT risk SWO focused over south-central PA highlighted by a 5% tornado prob. Remnants of an MCS currently over the midwest will affect the area Thursday morning. If this cloud cover limits precip to a stratiform rain for a period, that may limit some of the convective potential. Otherwise, low level shear and low LCL heights, especially over the southeast portion of our forecast area, would inidicate the potential for strong storms. Improving conditions are expected in the wake of the cold FROPA Thursday night with much drier air poised to arrive on Friday via refreshing NW breeze. Look for a nice end to the week with partly sunny skies and low humidity. The dry/low PW airmass will set the stage for a rather cool Friday night/AM Saturday with minTs ranging from the mid 40s over the NW Alleghenies to the mid 50s across the southeast valleys. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Dry and seasonably cool conditions look to settle in for the end of the week into the first half of the weekend. Northwest flow aloft in the wake of an upper trough axis and surface ridge moving out of the Great Lakes into the Ohio Valley will lead to cool/dry air advection on Friday as clouds lift/break up through the afternoon. Will likely see widespread temperatures in the mid-upper 40s by Saturday morning across a good portion of central PA, with low-mid 50s across the middle/lower Susquehanna Valley and farther west along the Mason-Dixon line. Shortwave trough pushing south across Ontario on Saturday will lead to backing flow aloft as modest return flow sets up for late Saturday and Sunday, spelling the return of shower chances across the Alleghenies late Saturday. A better shot for showers/storms will exist for all of central PA on Sunday as a surface low moves across Lake Ontario. Much of Monday should remain dry, outside of a few lingering early day showers across the northern tier. Another upper low looks to dig into the western Great Lakes/Midwest into Tuesday, which will once again lead to increasing moisture and subsequent shower/storm chances into midweek. Below normal temperatures look to remain the rule, with highs generally in the low 70s north to low 80s south and lows spanning the 50s with low 60s in the lower Susquehanna Valley. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... Mainly VFR, though showers and storms will be possible this afternoon mainly for southern PA. MVFR restrictions will be possible in TSRA. More widespread convection likely on Thursday with a FROPA crossing W to E. Outlook... Thu...Widespread TSRA impacts. Fri & Sat...No sig wx expected. Sun...Chance of a shower or thunderstorm. && .CLIMATE... It's been a wet July in some parts of central PA. Through July 27th, the monthly precipitation at Harrisburg is 7.99 inches which currently ranks 2021 as the 9th wettest July on record. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Steinbugl NEAR TERM...Steinbugl/Tyburski SHORT TERM...Steinbugl/Tyburski LONG TERM...Guseman/Ross AVIATION...Ross/Wagner CLIMATE...
Hazardous Weather Outlook National Weather Service State College PA 511 AM EDT Wed Jul 28 2021 PAZ004>006-010>012-037-041-042-045-046-049>053-057>059-066-290915- Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Tioga- Northern Lycoming-Sullivan-Southern Clinton-Southern Lycoming-Union- Snyder-Montour-Northumberland-Columbia-Dauphin-Schuylkill-Lebanon- Lancaster- 511 AM EDT Wed Jul 28 2021 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Severe thunderstorms with a damaging wind and isolated tornado threat are possible Thursday afternoon and evening. Locally heavy rainfall is also possible and may produce isolated flooding. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ017>019-024>028-033>036-056-063>065-290915- Clearfield-Northern Centre-Southern Centre-Cambria-Blair-Huntingdon- Mifflin-Juniata-Somerset-Bedford-Fulton-Franklin-Perry-Cumberland- Adams-York- 511 AM EDT Wed Jul 28 2021 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Isolated strong to marginally severe thunderstorms with locally damaging winds are possible during the afternoon and early evening. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Severe thunderstorms with a damaging wind and isolated tornado threat are possible Thursday afternoon and evening. Locally heavy rainfall is also possible and may produce isolated flooding. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. MRS
Special Weather Statement National Weather Service State College PA 442 PM EDT Wed Jul 28 2021 PAZ024-033-282130- Somerset PA-Cambria PA- 442 PM EDT Wed Jul 28 2021 ...A STRONG THUNDERSTORM WILL AFFECT PARTS OF SOMERSET AND CAMBRIA COUNTIES UNTIL 530 PM EDT... At 441 PM EDT, Doppler radar indicated a strong thunderstorm near Westmont, moving southeast at 25 mph. Wind gusts up to 50 mph are possible. Locations impacted include... Johnstown, Westmont, Windber, Belmont, Geistown, Southmont, Boswell, Dale, Davidsville, Paint, Jerome, Scalp Level, Daisytown, Tire Hill, Elim, Lorain, Brownstown, Jennerstown, Hooversville and Stoystown. LAT...LON 4037 7899 4022 7870 4006 7900 4020 7912 TIME...MOT...LOC 2041Z 309DEG 22KT 4033 7906 Travis
Special Weather Statement National Weather Service State College PA 443 PM EDT Wed Jul 28 2021 PAZ065-282130- York PA- 443 PM EDT Wed Jul 28 2021 ...A STRONG THUNDERSTORM WILL AFFECT PARTS OF YORK COUNTY UNTIL 530 PM EDT... At 442 PM EDT, Doppler radar indicated a strong thunderstorm over West York, moving south at 20 mph. Wind gusts up to 40 mph are possible. Locations impacted include... York, Weigelstown, Red Lion, Spry, Dallastown, Shiloh, East York, West York, Grantley, Tyler Run-Queens Gate, Emigsville, Glen Rock, North York, Jacobus, Yoe, Cross Roads, Loganville, New Salem, Winterstown and Seven Valleys. LAT...LON 3998 7683 4002 7674 3982 7654 3976 7681 TIME...MOT...LOC 2042Z 339DEG 16KT 3997 7677 DeVoir
The Sterling radar (KLWX), 125 km away, was scanning. The volume nearest the first event began at 20:49 UTC.
3 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph blew the roof off of a structure and knocked wires down in West York.
A severe thunderstorm produced winds estimated near 60 mph and knocked down several tents at the York State Fair. There were 6 injuries, with 3 of them transported to the hospital for further evaluation.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees at the intersection of Grantley Road and Shady Dell Drive south of York.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2021Every state in 2021This day in weather historyWarnings in Pennsylvania, July 2021
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: 966360, 978192, 966362.