A cold front crossed Pennsylvania the afternoon/evening of May 1, 2017. A squall line containing several bowing segments and mesovorticies formed in a strong vertical shear environment ahead of the front.
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 cold front crossed Pennsylvania the afternoon/evening of May 1, 2017. A squall line containing several bowing segments and mesovorticies formed in a strong vertical shear environment ahead of the front. This line produced widespread wind damage as it crossed central Pennsylvania, with several microbursts observed along with two EF1 tornadoes.
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 1, 2:02 PM EST, 23 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 302 PM EDT Mon May 1 2017 .SYNOPSIS... A strong cold will push east across the Commonwealth this afternoon into early tonight. The front will usher in brisk west to northwest winds and cooler air for Tuesday. Fair weather with milder temperatures will occur Wednesday under a weak ridge of high pressure. A new storm system is likely to affect the region from Thursday afternoon through Friday. Much colder air is expected for late Friday through the upcoming weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Tornado Watch #185 in effect until 10 PM... Latest radar shows a line of moderate showers moving toward my western zones. So far no lighting being observed but stability is eroding as breaks begin developing in the cloudcover of the warm sector that covers just about the entire CWA. Far eastern areas are experiencing the last vestiges of the cool air damming and marine layer that has kept cool- moist conditions in place. Conditions are falling into place for a widespread outbreak of potentially severe thunderstorms and even some isolated strong tornadoes. RAP is depicting EHI's of 1-3 (anything greater than 1 is significant) already in place over Central Pa. Deep layer shear is simultaneously a very impressive 50-70kt over most of my CWA. The main line of convection is starting to form over eastern Ohio, and the HRRR tracks it east across the area between about 20-01Z. The main mode of convection looks to be linear with bowing segments/QLCS storms, but the potential for rotation within isolated elements will be very high. LCL's are marginal but within the parameters that if a supercells begins to show strong gate to gate shear, tornadogenesis will be very possible. SPC has continued the ENHANCED risk over practically all of PA. Forecast storm total rainfall amount by midnight tonight will range from one-half of an inch, to one inch in some areas of Ncent and NW PA. Afternoon high temps should reach the mid/upr 70s...to near 80F in some of the Central and Southern Valleys. Anything slightly warmer than this spells more significant severe weather concerns, and could prompt SPC to raise the Day 1 outlook into the MDT category across portions of the state, considering the existing llvl boundaries and highly anomalous low-mid level shear. A narrow north/south ribbon of +3-4 sigma PWAT air along and just ahead of the cold front will support some locally heavy downpours and storm total QPF by 04Z Tuesday up over one inch in some spots. WPC highlights a small portion of my NERN zones with a MARGINAL risk of heavy rain/flooding. It's still too soon (with some uncertainties) to get into any type of flood watches at this point. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... Expect significant convection to be ongoing/near to exiting the extreme eastern CWA during the late evening hours tonight. Cold front forcing the convection will move east through the state overnight into Tuesday morning, advecting much chillier air into the state. Scattered to numerous rain showers may linger until 06Z before weak post frontal ridging slides east over the region after midnight accompanied by drier and cooler lvll air. Lows early Tuesday will vary from the mid 40s across the NW mtns, to the upper 50s in the SE. GEFS axis of 2-3 sigma WSW 850 mb winds and the presence of 45-50 kt winds occupying the top of the well-mixed layer (at around 4-5 kft agl Tuesday afternoon) will lead to sfc wind gusts easily in the 30 to 35 kt range, and perhaps even 5-10 kts higher. High temps Tuesday afternoon will be in the L50s across the NW mtns...L60s just to the SE of the I99/Rt 220 corridor, and upper 60s near and to the SE of I-81. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Cyclonic flow will dominate the region through much of the long term period with one upper trof exiting at the start of the period and a second arriving late week. Early on, a gusty NW wind and unsettled light showery weather will persisting mainly for the northern part of the state right into Wednesday. A chance for a more widespread/soaking (MDT to HVY) rain arrives Thu afternoon into Fri, as the latest 00Z Operational GFS/EC run and their EFSs are coming into decent/converging agreement with an area of low pressure progged to develop along the southern Appalachians and the lift north-northeastward. Although this event shows some pretty strong signals (even at this long time range) for a potential, widespread 1-2 inch rainfall late in the upcoming week, A wide and varying array of models solutions has been present prior to the latest model run or two to throw some uncertainty into the mix w/respect to the specific timing and amount of showers across the CWA. Fri night and Saturday will turn windy and quite cool with isolated rain showers falling across the central mtns, while the Alleghenies experiences more numerous rain showers...likely changing over to snow showers across most of the region. Cyclonic flow will begin to wane early next week, with slowly improving conditions, as the second upper trof lifts out. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... Haze and low clouds are burning off early this afternoon over the east. Two bands of SHRA are moving into and through central areas attm. Showers continue over the NW airspace. Southerly flow will get to the ground over the east as heating burns off stratus. Gusts over 25kts at all sites this afternoon ahead of the main line developing over eastern OH. Line of severe thunderstorms entering western PA this afternoon will arrive in our NW counties 19-20Z. This organized squall line will move over JST and BFD 20-21Z. As it does, it probably will be accompanied by increasing potential for 40-50KT surface wind gusts. There is some question concerning the intensity/timing into the eastern 1/2 of the airspace this evening. Will update with AMDs to add severe-storm details via TEMPO group as storms get closer. Frontal passage tonight will shift winds more to the west/southwest allowing clearing conditions between the upper trough/associated colder air and the front itself. Above mentioned colder air aloft rotating through the Great Lakes will bring sct showers into the NW airspace by Tuesday morning. Outlook... Tue...Breezy with MVFR cigs/rain showers likely NW airspace. Wed...Showers ending NW. MVFR cigs west becoming VFR. Decreasing winds. Thu-Sat...Widespread sub-VFR with periods of rain. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...Lambert LONG TERM...Lambert/Gartner AVIATION...Head
Hazardous Weather Outlook National Weather Service State College PA 214 PM EDT Mon May 1 2017 PAZ036-056>059-063>066-021815- Franklin-Perry-Dauphin-Schuylkill-Lebanon-Cumberland-Adams-York- Lancaster- 214 PM EDT Mon May 1 2017 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...This Afternoon and Tonight. Scattered showers and thunderstorms will be possible later this afternoon and evening. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. PAZ004>006-010>012-017>019-024>028-033>035-037-041-042-045-046- 049>053-021815- Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield- Northern Centre-Southern Centre-Cambria-Blair-Huntingdon-Mifflin- Juniata-Somerset-Bedford-Fulton-Tioga-Northern Lycoming-Sullivan- Southern Clinton-Southern Lycoming-Union-Snyder-Montour- Northumberland-Columbia- 214 PM EDT Mon May 1 2017 ...TORNADO WATCH 185 IN EFFECT UNTIL 10 PM EDT THIS EVENING... This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...This Afternoon and Tonight. Please listen to NOAA Weather Radio or go to weather.gov/StateCollege on the internet for more information about the following hazards. Tornado Watch. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
Special Weather Statement National Weather Service State College PA 226 PM EDT MON MAY 1 2017 PAZ004-011930- Warren PA- 226 PM EDT MON MAY 1 2017 ...THUNDERSTORMS WILL MOVE INTO WARREN COUNTY FROM THE WEST AROUND 3 PM EDT... At 223 PM EDT, Doppler radar indicated thunderstorms along a line extending from Girard to near Cambridge Springs to Greenville. Movement was northeast at 55 mph. At this speed, the storms should reach western Warren County by 3 PM EDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... These storms may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 4200 7925 4163 7929 4163 7961 4200 7961 TIME...MOT...LOC 1823Z 227DEG 47KT 4199 8029 4179 8017 4132 8028 Dangelo
The State College radar (KCCX), 143 km away, was scanning. The volume nearest the first event began at 19:24 UTC.
57 thunderstorm wind, 1 tornado, 1 hail. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees along Davey Hill Road.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees along York Hill Road south of Youngsville.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees along Old Pittsfield Road.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires on Canton Street in Warren.
A narrow, convergent path of intense damage was documented via aerial imagery after being discovered and documented by Forest Service personnel. Damage consisted entirely of uprooted and snapped hardwood and softwood trees. This is the continuation of a county-crossing track that began in Forest County.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees along Route 666 south of Sheffield.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees along Route 66 near James City.
A severe thunderstorm produced quarter-sized hail in Kane.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees in Wilcox.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees near Wilcox.
A severe thunderstorm produced a microburst with winds estimated near 90 mph just to the east of Custer City. Wind damage caused by the microburst began on northwest side of the Penn Hills Country Club and traveled southeastward for approximately three-quarters of a mile to near the intersection of Route 770 and Langley Drive. Most of the damage was to trees on the Penn Hills golf course property, some of which were snapped and others uprooted.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees southeast of Brandy Camp.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires near Curwensville.
A severe thunderstorm producing winds estimated near 60 mph produced roof and building damage north of Shinglehouse.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto a house on Venango Street.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees in the Meyersdale area.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees and wires near Schellsburg.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires near Osterburg.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and damaged a shed near Snow Shoe.
A severe thunderstorm producing winds estimated near 60 mph knocked down and snapped multiple trees near the intersection of Colerain Road and Route 45.
A severe thunderstorm producing winds estimated near 60 mph knocked down power lines along Route 550 near Stormstown.
A severe thunderstorm producing winds estimated near 60 mph knocked down and snapped numerous trees in Morrison's Cover Memorial Park in Martinsburg.
A severe thunderstorm produced winds estimated near 70 mph and knocked down or uprooted 60-80 trees in a wooded area near Russellville.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees in Woodycrest.
A severe thunderstorm producing winds estimated near 60 mph knocked down across a road northwest of Pennsylvania Furnace.
A severe thunderstorm producing winds estimated near 60 mph damaged a barn and a house west of Petersburg.
A severe thunderstorm producing winds estimated near 60 mph produced structural damage to a home in Tioga.
A severe thunderstorm producing winds estimated near 60 mph removed siding from a house in Tioga.
A severe thunderstorm producing winds estimated near 60 mph knocked down a large pine tree that blocked North Atherton Street.
A severe thunderstorm producing winds estimated near 60 mph knocked down a large tree near Pine Grove Mills.
A severe thunderstorm producing winds estimated near 60 mph knocked down a pine tree across Burrowes Road at Waring Commons on the Pennsylvania State University campus.
A severe thunderstorm produced winds estimated near 60 mph and knocked down trees and wires near Lebo Vista.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees near the Pennsylvania Military Museum.
A severe thunderstorm produced winds estimated near 70 mph and knocked down a swath of trees behind homes along Sand Ridge Road and Ponderosa Road north of Hublersburg.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees in Lock Haven.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees on homes in Lamar.
A severe thunderstorm produced winds estimated near 70 mph and knocked down a swath of trees near Spring Mills.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires near Mackeyville.
A severe thunderstorm producing winds estimated near 60 mph knocked down large tree limbs in Aaronsburg.
A severe thunderstorms produced a microburst with winds estimated near 80 mph, knocking down a swath of trees and damaging the roofs on three barns just west of Coburn.
A severe thunderstorm produced winds estimated near 70 mph and knocked down a swath of at least 50 trees on a ridge along Route 445 north of Millheim.
A severe thunderstorm produced winds estimated near 60 mph and knocked down or snapped approximately three dozen trees and damaged a pole barn northeast of Coburn.
A severe thunderstorm produced a 66 mph wind gust at the Lock Haven Piper Airport.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees near Burnham.
A severe thunderstorm produced winds estimated near 60 mph and knocked down trees in Jersey Shore.
A severe thunderstorm produced winds estimated near 70 mph and knocked down a large swath of trees approximately a mile long on a ridge north of I-80 near Loganton.
A severe thunderstorm produced winds estimated near 60 mph and knocked down numerous trees near Collomsville.
A severe thunderstorm produced winds estimated near 60 mph and knocked down numerous trees near Nisbet.
A severe thunderstorm produced winds estimated near 60 mph, knocking down several trees and damaging a barn roof southwest of Elimsport.
A severe thunderstorm produced a wind gust measured at 85 mph in Williamsport.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees in Mifflinburg, including a tree on a car on Market Street.
A microburst associated with a severe thunderstorm produced winds estimated near 80 mph, knocking down a swath of 60-80 trees southeast of Shunk.
A severe thunderstorm produced winds estimated near 60 mph and knocked down numerous trees west of Huntersville.
A severe thunderstorm producing winds estimated near 60 mph knocked down and snapped multiple large trees on Covered Bridge Road in Hillsgrove Township.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees on wires near Coalmont.
A severe thunderstorm producing winds estimated near 60 mph knocked down a large tree west of Rockhill.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees on wires in Doylesburg.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees east of Mount Pleasant Mills.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees near Selinsgrove.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2017Every state in 2017This day in weather historyThe tornado archive for Pennsylvania, 2017Warnings 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: 685905, 685906, 685907, 685908, 1019161, 685909, 685910, 685904, 685912, 685913, 683374, 685915, 685916, 685923, 685926, 685933, 685937, 685938, 685939, 685992, 685987, 685994, 686007, 685962, 685981, 685999, 685940, 685941, 685963, 685967, 685979, 686013, 685974, 686011, 685965, 685966, 686008, 685982, 685995, 683577, and more.