Severe Storms to Threaten Iowa Wednesday Night: Damaging Wind, Large Hail, Isolated Tornadoes Possible

DES MOINES, Iowa — Iowa is bracing for another round of severe thunderstorms Wednesday, with the National Weather Service warning that numerous severe storms are possible across the northern half of the state, capable of producing damaging wind gusts, large hail and a few tornadoes.

In a 5:05 a.m. update, forecasters placed a broad swath of northern Iowa — including Mason City, Algona, Charles City and Decorah — under the highest local risk category for the day, a level 3 out of 5, meaning numerous severe storms are possible. A level 2 risk covers a wide band through central Iowa, including Fort Dodge, Ames and Waterloo, while much of southern Iowa carries a lower-end risk for scattered thunderstorms.

Timing: late afternoon into tonight

Storms are expected to develop during the late afternoon and continue overnight, according to the Weather Service. Once they form, storms will move quickly, tracking to the northeast at 30 to 40 mph.

What to expect: wind, hail and a tornado threat

Forecasters identified three primary threats for Wednesday’s severe weather:

• Damaging wind: The primary threat of the day. Widespread gusts of 60 to 70 mph are expected, with isolated gusts up to 80 mph possible in a hatched area stretching from northwest Iowa into the north-central part of the state.
• Large hail: A secondary threat, with hail up to 1 to 2 inches in diameter — quarter to ping-pong ball size — possible in the strongest storms.
• Tornadoes: Considered possible, though not the main threat. The Weather Service said a tornado or two could occur, particularly in far northern Iowa.

The tornado, wind and hail outlooks released Wednesday morning all point to the same general area of greatest concern: a corridor from far northwest Iowa across the north-central and northeast parts of the state, generally along and north of a line from Storm Lake to Waterloo to Dubuque.

How to stay safe

The Weather Service is urging Iowans with outdoor plans Wednesday to stay weather-aware throughout the day and have multiple ways to receive warnings, such as a weather radio or phone alerts. If storms approach, forecasters recommend moving indoors and away from windows.

Residents in the highest-risk zone across northern Iowa should be especially prepared to seek shelter quickly if a warning is issued, given the potential for damaging winds near or above 70 mph and the possibility of a tornado.

The National Weather Service in Des Moines said it will continue to monitor the threat and issue updates as storms develop later Wednesday.