United States

Damaging thunderstorms will erupt from Nebraska to Minnesota and Wisconsin into Tuesday tonight. Large hail, damaging winds and tornadoes are the greatest threats.

On Monday, strong thunderstorms ignited across Wisconsin and blasted eastward over Michigan, southern Ontario and the waters of Lake Michigan and Lake Huron. The strongest storms produced damaging wind gusts that brought down trees and power lines. In addition, large hail to the size of baseballs pounded many locations in Wisconsin and Michigan.

This evening, the severe thunderstorm threat is draped a bit farther west across the northern Plains and the Upper Midwest. Nebraska, Iowa, South Dakota, Minnesota, Wisconsin and parts of Michigan and northwestern Ontario will be faced with damaging thunderstorms.

Cities in the threat zone include Thunder Bay, Ontario, Duluth, Minn., Minneapolis, Minn., and Sioux Falls, S.D. Residents will need to pay close attention to the weather into the evening hours.

Similar to Monday, large hail and damaging winds will once again be the greatest severe weather threat. Hailstones to the size of golf balls and wind gusts past 60 mph will not be uncommon.

A few of the strongest storms can also produce a short-lived tornado.

Building heat and abundant moisture will prime the atmosphere for an explosion of thunderstorms.

Initially, the thunderstorms that develop may be able to remain discrete, enhancing the risk for large hail and tornadoes. Later in the evening and at night, the storms will congeal into a cluster, with damaging wind gusts becoming the primary threat.

These nighttime thunderstorm clusters are often found along the peripheral of high pressure ridges. According to Meteorologist Evan Duffey, "The peripheral of a ridge is the location that separates a very warm and moist air mass from a cool and dry one. Thunderstorms are able to maintain themselves along this boundary for great distances before eventually collapsing during the early morning hours."

Severe weather that occurs at night is the most dangerous simply due to the fact that most people are asleep. Have a weather radio nearby that will wake you up in the event that a severe thunderstorm is threatening.

Be sure to have a plan in place before damaging thunderstorms strike. Heed all watches and warnings and be prepared to take swift action.

Keep checking back with AccuWeather.com for the latest severe weather information and updates.