The storm system responsible for bringing drought-relieving rain to the Northwest will continue to push eastward into the northern Plains and Midwest.
As this system moves eastward through the Plains, the threat for strong thunderstorms will develop this afternoon and evening.
A large dip in the jet stream has pushed a cooler air mass through the Pacific Northwest, dropping temperatures on the order of 10-15 degrees Fahrenheit in a single day.
The leading edge of this cooler and drier air mass will be the force behind the development of thunderstorms this afternoon from Duluth and Minneapolis, Minnesota; and as far south as Des Moines, Iowa.
Afternoon highs in these cities have been slowly creeping into the middle 80s F over the course of the week, and this new air mass will bring more seasonable weather to the region for the end of the week.
However, before the cooler weather arrives, showers and some strong thunderstorms will cut across the region today.
AccuWeather Senior Meteorologist Dan Pydynowski said, "A frontal boundary slicing eastward across the Upper Midwest today will move through a warm and moist air mass, triggering strong to severe thunderstorms."
While thunderstorms are expected to develop early in the afternoon, the strongest thunderstorms will hold off until the late afternoon into the overnight hours.
Rapidly deteriorating weather conditions will lead to greatly decreased visibility, causing traffic delays during the evening commute.
"These storms will bring heavy downpours and strong wind gusts before storms move eastward into Wisconsin and Illinois tonight", said Pydynowski
Heavy, gusty thunderstorms will quickly move eastward toward Madison, Wisconsin; and Cedar Rapids, Iowa, late this evening and into the overnight.
Torrential downpours can lead to rapidly rising water levels, increasing the changes of hydroplaning. Exercise caution while driving in inclement weather conditions.
The threat for strong thunderstorms will begin to diminish, sending a few showers and a few rumbles of thunder across cities like Chicago; Kansas City, Kansas; and St. Louis, Missouri, by dawn on Friday.