A lone severe thunderstorm developed in a moderately high CAPE, but fairly low shear environment and produced wind damage in southern York County during the afternoon of May 19, 2017.
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.
A lone severe thunderstorm developed in a moderately high CAPE, but fairly low shear environment and produced wind damage in southern York County during the afternoon of May 19, 2017.
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 May 19, 1:16 PM EST, 49 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 216 PM EDT Fri May 19 2017 .SYNOPSIS... A cold front will slide southeast across the state today. Cooler and drier air will follow for the weekend. Low pressure will track west of Pennsylvania early next week, with the trailing cold front coming through the region Sunday night or Monday. && .NEAR TERM /THROUGH TONIGHT/... The meso anal shows the cold front settling into my southern zones with the RAP indicating low level Theta-E advection going negative over all but the far southern stripe of the CWA. This is where the scattered convection is firing in the moderately unstable airmass along and ahead of the front. The best Cape of 1000-2000J extends along the MD border and the trend shows the atmosphere becoming more stable as the cool/negative Theta-E advection works south through the region. Wind shear has decreased markedly since this morning so the severe threat now seems to be mainly from an isolated pulse storm in the still warm and humid airmass. The convective threat will decrease as we lose heating and the front continues its push south. Basin average QPF will be generally 0.10 of an inch or less in southern PA. However, localized amounts of 0.25-0.50 inch are possible in places impacted by heavier showers and storms. High temps today ranging from the mid/upper 60s across far NW PA, to the upper 80s in the Lower Susq Valley will be a good 10-15 deg above normal across all but the far NW zones, where they will be near to slightly above normal. A lingering shower will be possible through mid evening before drier air works into all areas by midnight. Lows will range from the mid 40s to mid 50s north to south with lower dewpoints making for more comfortable sleeping conditions than the last couple of nights. && .SHORT TERM /SATURDAY/... Saturday is expected to remain dry, with the exception of a shower possibly working into the far SW before the sun goes down. Increasing mid/high clouds could mar what otherwise would be a nearly perfect mid spring day. Highs generally in the 70s will be a few degrees either side of normal for mid May. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... High pressure over New England will slowly retreat eastward on Sunday. The main effect will be to keep relatively stable air in place over central and eastern areas so while the chances for showers will begin to ramp up from west to east, the chances for thunder will be relatively low. The latest model guidance continues the idea of a cold front passing overnight Sunday into early Monday morning. While the rain chances will be high, the chances for severe will be very low given the time of day. So at this point the highest likelihood for showers and thunderstorms will be Sunday night and the first half of Monday with drier air beginning to work in for Monday afternoon. High temperatures are expected to be above normal right through the weekend until we begin to cool down by the end of the cycle. By Tuesday-Thursday highs will be near to several degrees below normal. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... Generally VFR will continue across central Pennsylvania through Saturday. The exception will be if a terminal takes a direct hit from the small shower/thunderstorm cells that are popping up over southern areas. Any restrictions will be brief. As the front pushes south of Pennsylvania late this afternoon and evening, the threat of precipitation will diminish with VFR conditions expected overnight and continuing into Saturday. The next system will introduce a slight chance of showers into the west Saturday evening, with more widespread showers developing later Sunday and Sunday Night. .OUTLOOK... Sun...Showers and thunderstorms likely west advancing east by late afternoon and evening. Mon...Becoming VFR with showers ending from west to east. Tue...VFR. Wed...Widespread restrictions developing with showers and thunderstorms. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...La Corte LONG TERM...La Corte/Lambert AVIATION...La Corte
Hazardous Weather Outlook National Weather Service State College PA 407 AM EDT Fri May 19 2017 PAZ004>006-010>012-017>019-037-041-042-045-046-049>053-200815- Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield- Northern Centre-Southern Centre-Tioga-Northern Lycoming-Sullivan- Southern Clinton-Southern Lycoming-Union-Snyder-Montour- Northumberland-Columbia- 407 AM EDT Fri May 19 2017 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. PAZ024>028-033>036-056>059-063>066-200815- Cambria-Blair-Huntingdon-Mifflin-Juniata-Somerset-Bedford-Fulton- Franklin-Perry-Dauphin-Schuylkill-Lebanon-Cumberland-Adams-York- Lancaster- 407 AM EDT Fri May 19 2017 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...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The Sterling radar (KLWX), 120 km away, was scanning. The volume nearest the first event began at 19:06 UTC.
1 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires along Faraway Drive in North Hopewell Township.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2017Every state in 2017This day in weather historyWarnings in Pennsylvania, May 2017
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: 692070.