The northern fringe of a surge of heat over the North Central states will be the focus for complexes of thunderstorms Friday night, some of which will have dangerous and damaging consequences.
The strongest storms have the potential to down trees and power lines. This has already been recorded in some parts of the Dakotas early Friday evening. Some areas will be hit with wind-driven, torrential rain and flash flooding.
The storms are capable of tracking for hundreds of miles, producing frequent lightning strikes, wind gusts to near hurricane force and heavy rainfall.
Storms firing over the Dakotas and Nebraska bring an elevated risk of producing very large hail and a few tornadoes.
Already, Friday afternoon, a small tornado made a brief touchdown approximately 150 miles northwest of Sioux Falls, S.D. Then a few hours later in the early evening, winds reached up to 85 mph and baseball-sized hail fell over parts South Dakota and Nebraska.
Rounds of thunderstorms will continue to fire over from northern Plains to the Great Lakes region during the balance of the weekend. A few locally severe thunderstorms can reach farther to the east over Michigan, southern Ontario, northern upstate New York and northern New England as well.
Some cities that will be in the path of the storms into Friday night include Bismarck and Fargo, N.D., Rapid City and Sioux Falls, S.D., Minneapolis, Minn., Eau Claire and Milwaukee, Wis., Sioux City and Des Moines, Iowa, Valentine and Omaha, Neb., and Chicago, Ill.
When a large area of hot, humid air develops, thunderstorms sometimes fire on the periphery of the heat as this is often the region where air is cooler aloft. Hence the term "ring of fire." When strong winds are present aloft over this fringe area, the storms can be severe and organize into complexes or lines. A strong thunderstorm complex is called a mesoscale convective system and a line of strong thunderstorms is called a squall line. The most intense and longest-lasting version of these is called a derecho.
Story by AccuWeather.com Expert Senior Meteorologist Alex Sosnowski.