A crossing shortwave trough led to the development of thunderstorms across the region during the midday and afternoon hours of the 22nd. Much of the region was impacted by cloud cover early on and was not able to destabilize sufficiently for severe weather.
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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 PBZ wrote it up.
A crossing shortwave trough led to the development of thunderstorms across the region during the midday and afternoon hours of the 22nd. Much of the region was impacted by cloud cover early on and was not able to destabilize sufficiently for severe weather. However, areas to the north and east of Pittsburgh, where more sun was seen and where the trough had yet to cross, saw thunderstorms take advantage of the synoptic support, instability and terrain influences. Indiana and Jefferson Counties took the brunt of the wind damage.
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 Pittsburgh, PA wrote its last area forecast discussion before the first event at Jun 22, 10:13 AM EST, 2 hours 30 minutes earlier.
Area Forecast Discussion National Weather Service Pittsburgh PA 1113 AM EDT Mon Jun 22 2020 .SYNOPSIS... Warm weather with periodic showers and storms is expected through midweek. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A shortwave trough will slowly move through the region today. The large scale ascension associated with this feature will weaken as it works to eject the ridge that was over a portion of the region on Sunday. This is also leading to the slow eastward progression. An area of showers with embedded thunderstorms will move through the entire region today. Cam models are indicating enhancement of convection this afternoon, mainly over the northern half of the region as this is the location where the main shortwave will swing through and where the more unstable atmosphere will be located. With the trough moving through, the area will see plenty of cloud cover which will work to lower convective strength. The atmosphere ahead of the trough will be unstable, but shear will be relatively weak. This would point to a situation where convection should be able to initiate quickly, but may have trouble intensifying and sustaining due to the weaker wind shear. Temperatures across the area will be a bit tricky due to the timing of the clouds and showers && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... Atmosphere will quickly stabilize tonight, and the axis of upper level energy will move over eastern PA. This will allow for a break in the activity late tonight. The next trough, and its associated surface cold front, will push through the area on Tuesday. This will provide the region with another round of showers and storms. Cloud cover and weak instability will work to limit convective strength and coverage. This system will exit to the east Tuesday night ending the threat for additional activity. Wednesday will start out dry, but another weak shortwave trough will provide the risk for scattered or isolated showers and storms Wednesday afternoon. Cooler temperatures are expected Tuesday and Wednesday. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Area will dry out to end the week. Another system will swing through this weekend, providing another risk for showers and storms. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... VFR conditions prevail at most terminals with scattered showers around for terminals along or west of the I-79 corridor due to shortwave trough crossing the region. Pockets of MVFR ceilings and occasional vsby restriction with the crossing of a shower, but ceilings should otherwise remain around 5000 feet today. Scattered showers and thunderstorms are expected to develop again this afternoon with a crossing shortwave trough before waning overnight. Fog development is possible Monday night, but confidence in affecting any terminal is too low to put in the TAF package for now. .Outlook... Periodic rain and restriction chances anticipated are likely through mid week with several passing disturbances and a frontal approach. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. &&
Hazardous Weather Outlook National Weather Service Pittsburgh PA 904 AM EDT Mon Jun 22 2020 MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023- 029-031-073>076-WVZ001>004-012-021-509>514-231315- Garrett-Tuscarawas-Carroll-Columbiana-Coshocton-Harrison- Jefferson OH-Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango- Forest-Lawrence-Butler-Clarion-Jefferson PA-Beaver-Allegheny- Armstrong-Indiana-Washington-Greene-Westmoreland-Westmoreland Ridges- Fayette-Fayette Ridges-Hancock-Brooke-Ohio-Marshall-Wetzel-Marion- Monongalia-Ridges of Eastern Monongalia and Northwestern Preston- Preston-Eastern Preston-Western Tucker-Eastern Tucker- 904 AM EDT Mon Jun 22 2020 This Hazardous Weather Outlook is for western Maryland, east central Ohio, northwest Pennsylvania, southwest Pennsylvania, western Pennsylvania, northern West Virginia and the northern panhandle of West Virginia. .DAY ONE...Today and tonight. Thunderstorms will develop across the region this afternoon. A few storms may become severe, with damaging wind and large hail as the primary threats with the strongest of storms. Localized flooding may also be possible with heavy downpours. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures.
The State College radar (KCCX), 93 km away, was scanning. The volume nearest the first event began at 17:41 UTC.
6 thunderstorm wind. Local standard time, as filed.
A number of trees were down between Vintondale and Wehrum.
In Henderson Township, multiple trees were reported to be down and damage to several structures was noted.
Downed trees caused damage to power lines and cars.
Due to multiple downed trees, US Route 119 between Sykesville and State Route 410 was closed.
Damage to a structure and a car was reported to be from downed trees.
Multiple trees and power lines were down across Ringgold Township.
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, June 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: 905205, 905207, 905208, 905214, 905216, 905218.