A storm system that produced strong thunderstorms across Montana and the Dakotas on Saturday will shift eastward and target the Midwest into Labor Day.
According to AccuWeather Senior Meteorologist Matt Rinde, "A frontal system will provide two opportunities for severe weather to end the extended Labor Day weekend."
Damaging winds, hail and torrential downpours will be the main threats with these storms into Labor Day.
Plenty of warm and humid air will be present from Iowa to Minnesota and Wisconsin to help fuel these storms.
"Storms will converge into a squall line and move across Minnesota and Iowa from late Sunday afternoon into Sunday evening," according to AccuWeather Meteorologist Becky Elloitt.
"The storms' progression eastward will bring them into western Wisconsin and eastern Iowa Sunday night," she added.
Cities at risk for severe thunderstorms into Sunday night include Minneapolis and Duluth, Minnesota; Madison, Wisconsin; Des Moines and Cedar Rapids, Iowa; Omaha, Nebraska; and Thunder Bay, Ontario.
Storms are expected to weaken below severe limits prior to reaching eastern Wisconsin, including Green Bay and Milwaukee.
Travel could become dangerous at times across interstates 35, 80, 90 and 94. Drivers should be alert when traveling at high speeds as wet roads could increase the risk of hydroplaning.
Never drive through a flooded roadway. Only a few inches of rushing water could wash away vehicles.
Sunshine, cooler air and less humidity will build across Minnesota and Wisconsin on Labor Day as an area of high pressure builds into the Upper Midwest. High temperatures will be within a few degrees of normal for the second week of September.
While Minnesota and Wisconsin dry out for Labor Day, strong storms will target portions of the central Plains on Labor Day.
A departing high pressure system to the north will allow for another round of unsettled weather. A warm southerly flow will develop on Monday afternoon and increase dew points to uncomfortable levels.
Storms will develop across the same frontal boundary that caused showers and thunderstorms across the Upper Midwest on Sunday.
Dew points better illustrate the amount of moisture in the air, which relates to relative humidity.
Warm, moist air is crucial for strong thunderstorms to develop.
Those planning on spending Labor Day outdoors whether it's having a barbecue or taking a trip to the apple orchards, should keep an eye to the sky in case a thunderstorm approaches.
Places like Des Moines, Iowa; Omaha, Nebraska; and even Kansas City will have these storms.
Thunderstorms are expected to develop across the region by the late-afternoon hours and continue through the nighttime hours on Monday.
Thunderstorms should clear the region during Tuesday afternoon. Thunderstorms are not expected to be severe on Tuesday.
Anyone traveling across these areas into Labor Day should be alert for dangerous traveling conditions at times and use AccuWeather Minutecast® to keep up to date with changing weather conditions across your area.
Stay updated with Accuweather.com throughout the day to monitor potential hazards that might affect your holiday celebrations.
Story written by AccuWeather Meteorologists Brett Rossio and Brett Rathbun.