Rounds of drenching, severe storms to batter midwestern US this week

By Kristina Pydynowski, AccuWeather senior meteorologist

July 17,2017, 11:23:19AM,EDT

 

 

Additional rounds of thunderstorms will take aim at the Upper Midwest this week, threatening to turn severe and further heightening the flash flood danger.
After calm weather over the weekend, steamy air will quickly surge back across the Upper Midwest on Monday, setting the stage for thunderstorms to erupt across Minnesota and the eastern Dakotas in the afternoon and at night. Spotty strong thunderstorms could even ignite as far south as central Nebraska.

While a widespread outbreak of severe weather is not expected, AccuWeather Meteorologist Kyle Brown is concerned for a few of the thunderstorms to turn violent.
“Hail, damaging winds and locally heavy rain are the main hazards,” Brown said. There can also be an isolated tornado.
Residents in Fargo; Aberdeen, South Dakota; and Duluth, Minnesota, will have to keep an eye to the sky and be prepared to seek shelter.
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This zone of thunderstorms will continue to press to the south and east through Wednesday. Later on Tuesday, another round of severe weather is expected to ignite from Wisconsin to Iowa and eastern South Dakota.
Once again, Brown is concerned for hail, damaging winds and flooding rain with the strongest thunderstorms on Tuesday.
This band of showers and thunderstorms will reach Detroit and Chicago on Wednesday. However, a strong push of dry air will not follow.

Instead, additional rounds of thunderstorms will ignite over the northern Plains and track to the Great Lakes into later in the week.
Each bout of thunderstorms will likely bring the risk for at least localized severe weather. The areas at risk each day will depend on exactly where fronts settle, as well as lingering showers/cloud cover from the previous day’s thunderstorms.
"There is concern that the weather pattern this week will potentially be conducive for a long-lived cluster of damaging thunderstorms, known as a derecho, to ride the rim of the heat baking the central Plains later Wednesday into Thursday," AccuWeather Meteorologist Brett Rossio said.
"While we will pin down a more precise track this potential cluster will take in the coming days, latest indications point toward the corridor from eastern South Dakota to northern or central Illinois at greatest risk."
The heaviest thunderstorms each day this week could also drop several inches of rain in a matter of a few hours. Where these thunderstorms repeat over the same areas, rainfall could reach over half a foot and flash flooding will threaten lives and property.
“By the time the round of thunderstorms tracks through the Upper Midwest on Wednesday night, areas that have seen heavy rain earlier in the week will be especially vulnerable to flash flooding,” Brown said.
This concern will only expand to more communities as additional downpours follow later in the week.
Southeastern Wisconsin and northeastern Illinois are already more susceptible to flooding after heavy rain this past week left the ground saturated and rivers running high.
Major river flooding continues on the Fox and Des Plaines rivers.
On Saturday, the Des Plaines River near Gurnee, Illinois, rose above its previous record crest of 11.95 feet from Sept. 27, 1986.
On the other hand, parts of the northern and central Plains are in need of rain.
An extreme drought is currently affecting the Missouri River valley from northern South Dakota to eastern Montana, according to the United States Drought Monitor.
Pockets of severe drought extend as far to the east as Iowa and as far south as Texas and Oklahoma.
The rounds of thunderstorms may develop far enough to the west to help ease the drought conditions in part of the area.