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Severe Thunderstorms July 18-19, 2020

A line of strong to severe thunderstorms moved across nearly all of Upper Michigan in the late night hours of Saturday July 18 and into the early morning hours of Sunday July 19.

Significant wind damage was observed in a narrow west-to-east swath from near Nisula, through Alston, Pelkie, Baraga, L'Anse, and Pequaming. Straight-line winds estimated at 90-100 mph in this narrow corridor caused a barn to collapse and other roof damage near Nisula, and a roof to be torn off a home in Pequaming. This segment of the line later produced a 76 mph wind gust at Stannard Rock in Lake Superior.

Other less significant wind damage was scattered throughout western and central Upper Michigan. Widespread power outages and numerous snapped or uprooted trees were reported throughout Gogebic, Ontonagon, Houghton, Baraga, and Marquette counties. One injury was reported in Marenisco when a tree fell onto a vehicle that was occupied at the time.

Heavy rainfall also accompanied these storms, with widespread reports of 1-2" of rain. This rainfall caused localized shoulder and trail washouts, but no major flooding was observed.

Estimated peak wind gust speed from this line of thunderstorms

Click this link for a complete list of reports of wind damage and heavy rainfall from this event.

Environment
Radar
Photos
Social Media Messaging

Environment


300 mb Height and Wind at 10 pm EDT July 18	500 mb Height and Vorticity at 10 pm EDT July 18	700 mb Height and Relative Humidity at 10 pm EDT July 18	850 mb Height and Temperature at 10 pm EDT July 18

850 mb Height and Wind at 10 pm EDT July 18	Mean Sea Level Pressure and Surface Dew Point at 10 pm EDT July 18	700-500 mb Lapse Rates at 10 pm EDT July 18	Surface-based CAPE and 0-3 km Storm Relative Helicity at 10 pm EDT July 18

Vertical profile near Nisula at 9 pm EDT July 18	Vertical profile near Nisula at 10 pm EDT July 18	Vertical profile near Nisula at 11 pm EDT July 18	Vertical profile near Nisula at 12 am EDT July 19

Radar

Note: Radar data from KMQT was not available for this event due to the System Life Extension Program (SLEP) maintenance that was underway at the time.


KDLH Radar, reflectivity and velocity, at 12:00 am EDT July 19	KDLH Radar, reflectivity and velocity, at 12:21 am EDT July 19	KDLH Radar, reflectivity and velocity, at 12:40 am EDT July 19	KDLH Radar, reflectivity and velocity, at 1:00 am EDT July 19

KGRB Radar, reflectivity and velocity, at 12:03 am EDT July 19	KGRB Radar, reflectivity and velocity, at 12:21 am EDT July 19	KGRB Radar, reflectivity and velocity, at 12:40 am EDT July 19	KGRB Radar, reflectivity and velocity, at 1:00 am EDT July 19

Photos


A house with its roof torn off in Pequaming, courtesy of Will Wiggins	Additional roof damage in Pequaming, courtesy of Will Wiggins	Tree damage 7 miles NW of Baraga, courtesy of our Co-Op Observer	Tree damage 7 miles NW of Baraga, courtesy of our Co-Op Observer

A collapsed barn in Nisula, courtesy of Keith Alan Almi II	Tree damage along Pequaming Rd, courtesy of Wayne Abba	Tree damage 7 miles NW of Baraga, courtesy of our Co-Op Observer	Tree damage in Keweenaw Bay, courtesy of Keweenaw Bay Fire Department

Downed trees blocking a road in Pelkie, courtesy of Warren Mattson	Tree snapped off in Nisula, courtesy of Philip Creech	Tree damage near the Dead River Basin, courtesy of Linda Derocher	Tree damage in Ironwood, courtesy of Rick Turonie

Tree toppled in Big Bay, courtesy of Mike Clawson	Roof damage, courtesy of Jeff Renshaw	Tree uprooted in Alston, courtesy of Lilly Antonia	Tree knocked down into a building in Marquette, courtesy of Erin Menhennick