Bands of showers and thunderstorms developed well ahead of an approaching cold front in a moderate to high CAPE and moderate shear environment over central PA during the afternoon and evening hours of May 29, 2020. Sporadic wind damage was observed, along with an isolated report of quarter-sized hail.
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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.
Bands of showers and thunderstorms developed well ahead of an approaching cold front in a moderate to high CAPE and moderate shear environment over central PA during the afternoon and evening hours of May 29, 2020. Sporadic wind damage was observed, along with an isolated report of quarter-sized hail.
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 29, 10:27 AM EST, 1 hour 41 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 1127 AM EDT Fri May 29 2020 .SYNOPSIS... Summerlike conditions with above average temperatures will last one more day with scattered strong to severe thunderstorms possible this afternoon and evening. A noticeably cooler and drier/less humid airmass will move into the area over the weekend with temperatures trending below normal into early next week. && .NEAR TERM /THROUGH TONIGHT/... 11 UTC radar shows the last cluster of showers exiting Tioga County. Not anticipating much in the way of shower activity through mid/late morning. Hires guidance was rather bullish on expanding showers over the Chesapeake Bay region up into the southeast zones but that did not occur. Very summerlike and muggy/humid start to the day with temps and dewpoints in the 60s to low 70s. Upper level energy over the Mid-South and Upper Midwest will consolidate over the lower Great Lakes by this evening and quickly translate into New England overnight. The large scale lift associated with this shortwave trough along with strong boundary layer heating of very moist airmass (65-70F dewpoints) should support convective development by 18Z. The 00Z HREF shows one area of storms ahead of a pronounced cold front moving into the northwest mtns by 21Z while another band of storms initiates in the lee of the Alleghenies perhaps along lee-side trough with corridor a greatest instability over the Susquehanna Valley. The greatest coverage of showers/storms should occur from mid-late afternoon through the evening before weakening/shifting to the east and fading out by tonight. Storms will evolve within a strongly sheared southwesterly flow regime. While vertical shear seems supportive of supercells, and a few may develop, it appears thunderstorm clusters and line segments may be the more common storm mode. Scattered damaging winds, some hail, and perhaps a tornado or two are possible. SPC has expanded the SLGT risk D1 outlook to cover the remainder of PA. A sufficiently moist and unstable atmosphere will be supportive of locally heavy rainfall, however the forward speed of cells and overall scattered coverage should limit short duration flooding potential. 00Z HREF 24-hr probability-matched mean QPF shows to stripes of 1-2 inches over the far northwest and across the central ridge/valley region which aligns with the D1 WPC MRGL risk ERO. Cooler and drier air will filter into CPA tonight behind the front with min temps falling into the low 50s in the northwest. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... After a week of summerlike weather, a noticeable cooldown will occur over the weekend and last into early next week. Can't rule out a stray shower on Saturday over the western Alleghenies tied to secondary cold front/sfc trough. Max temps will trend lower with fcst departures 8-15 degrees below average by Sunday with highs ranging from the upper 50s in the northwest to near 70F in the LSV. Low temps will get rather chilly by Sunday night in the upper 30s to mid 40s, with patchy frost not out of the question in the usually colder spots across the northern tier. && .LONG TERM /MONDAY THROUGH THURSDAY/... Early next week, models are in good agreement on an extended period of NW flow as a large scale upper trough sharpens over SE Canada and the Eastern US. An expansive sfc high pressure builds back in across the Ohio Valley and drifts just south of PA by Tue and then offshore by the middle of the week. Expect mainly dry weather and cooler less humid conditions Mon-Tue (including a couple of chilly mornings, though some cirrus overhead may keep mins from bottoming out in the 30s over the northern mountains). Quick hitting shortwave trough slides through on Tue and may produce some scattered light showers. The longwave trough flattens a bit briefly before sharpening again as large ridge builds over central parts of the country. This will allow another weak shortwave or two to ripple by overhead on Thu which will interact with a leftover weak surface boundary (from Wed) to keep mention of showers in the forecast. The first half of next weekend is looking pleasant and dry. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... At 12z, MVFR cigs were observed still being observed in the Lower Susq Valley /LNS, with generally VFR cigs elsewhere. BFD has briefly tanked to IFR /bkn006/, but I think this will scatter out quickly as the sun rises. Isolated SHRA were drifting northward across northern PA, in the vicinity of BFD and IPT. A southwesterly breeze of 10-20 kts will develop late this morning and continue through the afternoon. Scattered showers and thunderstorms will develop ahead of an approaching cold front and sweep eastward across central PA through the aftn and evening hours. Brief gusty winds are possible in the vicinity of any storms. Expect improving conds this weekend, as cooler and drier air moves in behind the departing cold front. The next decent chance for showers will arrive next Tuesday with a system approaching from the Great Lakes. Outlook... Fri night...SHRA/TSRA ending west to east. Sat...MVFR cigs poss NW, otherwise no sig wx. Sun-Mon...AM Fog poss. Otherwise VFR. Tues...chc SHRA/MVFR, mainly NW. && .CLIMATE... A record daily rainfall of 1.43 inches was set at Williamsport yesterday. This breaks the old record of 1.22 inches set back in 1968. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM...Steinbugl LONG TERM...Lambert/Banghoff/Radzanowski AVIATION...Evanego CLIMATE...
Hazardous Weather Outlook National Weather Service State College PA 455 AM EDT Fri May 29 2020 PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066-300900- Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield- Northern Centre-Southern Centre-Cambria-Blair-Huntingdon-Mifflin- Juniata-Somerset-Bedford-Fulton-Franklin-Tioga-Northern Lycoming- Sullivan-Southern Clinton-Southern Lycoming-Union-Snyder-Montour- Northumberland-Columbia-Perry-Dauphin-Schuylkill-Lebanon-Cumberland- Adams-York-Lancaster- 455 AM EDT Fri May 29 2020 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Scattered severe thunderstorms are possible this afternoon and evening. Damaging winds 60 mph or greater are the primary threat, followed by large hail exceeding 1 inch in diameter. Locally heavy rainfall is also possible and may cause isolated flooding. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. MS
Special Weather Statement National Weather Service State College PA 1158 AM EDT Fri May 29 2020 PAZ004-005-010-291700- Warren-McKean-Elk- 1158 AM EDT Fri May 29 2020 ...STRONG THUNDERSTORMS POSSIBLE THIS AFTERNOON... At 11:55 AM, Doppler radar indicated a line of developing thunderstorms in western Pennsylvania. These storms may continue to intensify as they approach Warren, McKean, and Elk Counties between 1 PM and 3 PM this afternoon. Stay weather aware and have multiple ways to receive warnings. Colbert
The State College radar (KCCX), 145 km away, was scanning. The volume nearest the first event began at 17:06 UTC.
17 thunderstorm wind, 1 hail. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires on Main Street in Tidioute.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires on Rankin Street in Warren.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires on Kinzua Road east of Warren.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto a home in South Middleton Township.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires along Clarks Valley Road near Tower City.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree and wires north of York Springs.
A severe thunderstorm producing winds estimated near 60 mph knocked down several trees in Lower Allen and Upper Allen Township.
A severe thunderstorm producing winds estimated near 60 mph knocked down a large tree across Route 134 south of Gettysburg.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees and wires in the vicinity of Pine Grove.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto Hergelrode Drive near King Street southwest of Myerstown.
A severe thunderstorm produced quarter-sized hail and knocked down large tree limbs in Shunk.
A severe thunderstorm producing winds estimated near 60 mph knocked down numerous trees in Bradford, including a tree onto a home.
A severe thunderstorm producing winds estimated near 50 mph knocked down a tree at the corner of Cotner Road and Mill Road east of Turbotville.
A severe thunderstorm producing winds estimated near 50 mph knocked down a tree in the 600 block of Ridge Road west of Liverpool.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto a home in Herndon.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees in Sunbury.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires in Montour and Catawissa Townships.
A severe thunderstorm producing winds estimated near 50 mph knocked down a tree onto Millertown Road west of Orangeville.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2020Every state in 2020This day in weather historyWarnings in Pennsylvania, May 2020
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: 884717, 884718, 884719, 889534, 889535, 889536, 889538, 889539, 889541, 889542, 884716, 889544, 889545, 889547, 889548, 889549, 889551, 889553.