I've mentioned a couple of times in my recent discussions of what looks like a stormy last ten days of June across portions of the Plains and Upper Midwest. One of the first dominoes to fall in this transition from the very active Spring 2024 pattern to a more summerlike pattern is a weekend storm system that could bring a round of severe weather to the Upper Midwest.
As of mid-week, a large ridge of high pressure has expanded across the Midwest and Northeast US with cooler temperatures across the Northwest and a very active jet stream racing between the two contrasting air masses. An upper-level disturbance will track from the Northern Plains into the Great Lakes over the weekend, with a surface low tracking across central Minnesota and northern Wisconsin during the day on Saturday. A warm front will extend eastward from the surface low, with a trailing cold front stretching back into the Central Plains. In the warm sector, summertime heat will be cooking with afternoon high temperatures around 90 deg F and dew points in the lower 70s.
As upper-level support overspreads the warm sector and the cold front pushes east scattered severe thunderstorms should ignite from southern Minnesota and western Wisconsin into Iowa and northwest Kansas.
The bones of this evolution have been very consistent on global models, but details concerning the thermal environment, location of important frontal boundaries, and other mesoscale details still have a long way to go toward determining where any corridors of enhanced severe weather potential may exist, and the location of greatest risk for individual severe hazards across this broad geographic area. Additionally, it's possible one or more organized storm clusters could emerge later in the period potentially surging into portions of northern Missouri or Illinois after dark with some continued severe risk.
Still, at four days out Saturday looks like a Midwestern chase day to me, and a Saturday that folks regionally will need to be weather aware.
My current favored region for severe storms on Sat, June 22nd without the annotations:
