The National Weather Service issued a tornado watch that remains in effect until midnight Sunday, and a flash flood watch for Story County that goes into effect at 6 p.m. Sunday and runs through Monday morning.

A tornado watch means that conditions are right for tornados to form, while a warning means that it is likely a tornado is currently forming or has touched down.

Two flood warnings are also in effect. The first will affect Squaw Creek at Ames until Tuesday morning. Moderate flooding is forecasted. The flood stage is nine feet, and flooding is expected to rise to 14.2 feet Monday. At 14 feet water is over South Duff Avenue. The other flood warning was issued for the South Skunk River. It is in effect until Wednesday morning. Moderate flooding is forecasted for the South Skunk River, too. The river is expected to rise to 23.6 feet, and at 23 feet the Shady Grove Trailer Park homes along 16th Street and the railroad northeast of Cambridge begin to flood.