Des Moines, Iowa – Iowans will contend with a dangerous combination of oppressive heat and severe thunderstorms today, with heat index values climbing above 105 degrees before strong storms develop later this afternoon and evening. Damaging winds are expected to be the primary threat, but large hail, isolated tornadoes and heavy rainfall are also possible.
According to the National Weather Service in Des Moines, a few thunderstorms this morning across northern Iowa could produce gusty winds before conditions briefly quiet down. By after 5 p.m., stronger thunderstorms are expected to develop and expand southeast across the state, with the highest risk centered over central and northeastern Iowa.
Forecasters place much of central Iowa, including Des Moines, Ames, Marshalltown and Waterloo, under an Enhanced Risk (Level 3 of 5) for severe weather, while surrounding areas remain under a Slight Risk (Level 2 of 5). Storms will move southeast at around 35 mph, with damaging straight-line winds posing the greatest hazard. Large hail, isolated tornadoes and pockets of heavy rainfall are also possible.
Adding to the concern, a Heat Advisory is in effect from noon until 8 p.m. for much of central and southern Iowa. Afternoon highs in the 90s combined with high humidity will push heat index values to 100 to 105 degrees, increasing the risk of heat-related illness.
Residents should stay hydrated, take frequent breaks in air-conditioned spaces, avoid strenuous outdoor activities during the hottest part of the day and make sure they have multiple ways to receive severe weather warnings this evening. Never leave children or pets inside parked vehicles. Additional watches and warnings are likely as storms develop later today.
