Severe Storms Likely in the Upper Midwest Through the Weekend

July 23,2016
Strong to severe thunderstorms, with damaging wind gusts and large hail, will take aim on the Upper Midwest and Great Lakes regions on Sunday.
Storms became fatal in Vermont on Saturday as severe storms knocked trees down.
In addition, torrential downpours may cause flash flooding in some areas of the northern Plains States.

Current Radar, Watches and Warnings.

(MORE: Storm Damage in the Midwest)
The severe weather is being triggered by disturbances sometimes called "ridge riders" by meteorologists since they are moving along the northern periphery of a hot ridge of high pressure aloft. That high-pressure system is the same one responsible for bringing dangerous heat to the central and eastern U.S. through this weekend.
(MORE: Dangerous Heat Ahead This Week)
Below are more details on the forecast into this weekend.

Thunderstorm Forecast

Sunday

• Forecast: The threat for scattered severe thunderstorms shifts eastward to the Great Lakes area. A few severe storms are possible from Michigan down to the Ohio River. 
• Impacts: A few storms may turn severe, with large hail damaging wind gusts being the main threats.
• Cities: Chicago | Traverse City, Michigan | Fort Wayne, Indiana | Detroit

Sunday's Thunderstorm Forecast

Monday

• Forecast: Severe storms roll into the Northeast and upper Ohio River valley.
• Impacts: A few strong to marginally severe storms capable of hail and damaging winds will be possible.
• Cities: Pittsburgh | New York City | Columbus, Ohio | Concord, New Hampshire

Monday's Thunderstorm Forecast

Storm Reports

Saturday
Storms raced southeastward across New England resulting in dozens of wind damage reports in Vermont and New Hampshire.
One person was killed in Hubbardton, Vermont when trees were knocked down.
One person was injured in Luzerne, New York when trees fell on their home.
For more information about these reports, please see our impact article.
Wind gusts of 65 to 80 mph were reported from Independence to Buchanan, Iowa as severe storms marched through eastern Iowa.
Friday
Scattered severe storms crossed through the Dakotas during the evening on Friday bringing large hail and gusty winds. In Meadow, South Dakota wind gusts of 90 to 100 mph were recorded. In Firesteel, South Dakota hail in excess of 2.0" in diameter fell.
Two tornado were confirmed in eastern Washington state by the National Weather Service. One was near Airway Heights and the other near Mold. Both were rated EF-0.
Thursday
Early Thursday morning, severe storms moved through Duluth, Minnesota, where trees and power lines were knocked down. In northern Wisconsin, winds gusted to 75 mph in Ashland.
Later Thursday, the severe threat shifted south and east into southern Wisconsin and northern Illinois. Construction damage was reported on the University of Wisconsin-Madison campus due to 60 mph wind gusts from the storms.  
Ridge Rider Pattern Triggers Storms

Disturbances in the middle portion of the atmosphere ride along the northern periphery of the hot high-pressure system.

A massive ridge of high pressure aloft (bulge in the jet stream) is anchored across a large portion of the nation. Locations underneath this ridge will have a low chance for thunderstorms.
A couple of strong disturbances often called "ridge riders" by meteorologists will move across the top of this ridge, however, and they will produce thunderstorms and some will turn severe.
An upper-level disturbance will progress eastward into the Northeast on Friday.
A second disturbance will produce another round of scattered severe thunderstorms by Friday night and Saturday across the Upper Midwest.
MORE: Lightning Strikes on Iconic Places