AcuteAlert: Moderate Risk Expanded, Damaging Winds Expected Tonight
A significant severe weather event is expected to impact parts of northern Iowa this afternoon and tonight. The Storm Prediction Center has issued a Moderate Risk—level 4 out of 5—for severe thunderstorms stretching from eastern South Dakota through southern Minnesota and into northern Iowa.
What’s Expected in Iowa
Storms are expected to begin developing in eastern South Dakota this afternoon and race southeast into Minnesota and northern Iowa by evening and into the overnight hours. These storms will likely organize into one or more intense clusters—what meteorologists call a Mesoscale Convective System (MCS)—capable of producing widespread, destructive straight-line winds.
Key threats include:
Damaging winds between 75–90 mph
A few tornadoes, especially early in the event as storms may start out more isolated
Large hail, primarily early in storm development
Why this setup is concerning:
A hot, humid, and unstable air mass will be in place across Iowa today, with plenty of fuel for storm development (what meteorologists call high CAPE—a measure of storm energy). Combine that with fast upper-level winds and a boundary from earlier storms, and you have a recipe for organized, fast-moving, and potentially damaging storm clusters.
These clusters are expected to form along a temperature boundary (a baroclinic zone) that stretches across northern Iowa. As storms track southeast along this boundary, they could maintain strength well after sunset—meaning parts of Iowa may face severe storms after dark, when they’re harder to see and more dangerous.
Timing for Iowa
Storm arrival: Late afternoon to early evening in northwest Iowa
Widespread impact: Mid-evening through the overnight hours for northern and northeast Iowa
Greatest risk: Along and north of U.S. Highway 20
What You Can Do Now
Prepare for damaging winds: Bring in loose outdoor items, secure trampolines and patio furniture
Review your tornado safety plan, especially if you live in a mobile home or lack a basement
Charge devices and weather radios in case of power outages
Stay weather aware after dark—use a trusted weather app or NOAA weather radio to receive warnings overnight
Bottom Line
This is a potentially high-impact event, especially if storms organize into a fast-moving complex. Northern Iowa is squarely in the path, and the threat includes powerful winds, large hail, and possible tornadoes. Make sure your weather alerts are turned on and check back for updates throughout the day.
