A tornado watch is in effect until 7 p.m. Wednesday for Greene, Boone, Dallas and Story Counties, as well as the city of Ames. 

For precautionary measure, the National Weather Service tells residents of these areas to take cover immediately. They recommend people move to a basement or interior room on the lowest floor of a sturdy building and avoid windows.

For people who are outdoors, in a mobile home, or in a vehicle, it is recommended to move to the closest “substantial structure” to protect from debris.

The National Weather Service says these storms could also include damaging winds of up to 75 mph.

The National Weather Service says isolated incidents of hail, up to 1.5 inches in diameter, are possible, as well as a 20 percent probability of one or more F2-F5 tornado across 21 different counties in Iowa. 

These counties include Boone, Dallas, Grundy, Hamilton, Hardin, Jasper, Marshall, Polk, Poweshiek, Story, Tama, Webster, Blackhawk, Butler, Franklin, Humboldt, Wright, Bremer, Mahaska, Wapello and Greene.

Ames is under a flash flood watch until 7 p.m. Wednesday and a river flood watch until 1 p.m. on Saturday, June 23.