Portions of Iowa under ‘extreme heat watch’ as a heat dome expands over the Midwest this week

The National Weather Service is warning Iowans of “dangerously hot and humid conditions” coming to the region this week, forecasting the heat index could reach temperatures of 110 degrees.

The National Weather Service’s Quad Cities Bureau has issued an extreme heat watch in effect for parts of Eastern Iowa, Western Illinois and Northeast Missouri. It will begin Tuesday afternoon and last through Thursday evening.

As of Monday morning, the extreme heat watch is in place for the following Iowa counties:

Meteorologists also report thunderstorms are possible Thursday, although it was too early Monday to determine whether there will be a threat of severe weather.

As of Monday afternoon, the NWS was predicting the hottest temperatures would be between noon and 6 p.m. each day, Tuesday, Wednesday and Thursday.

Many Eastern Iowa cities are expected to see triple-digit heat with the heat index reaching 100 to 110 degrees Fahrenheit.

State climatologist Justin Glisan told the Washington Post this is the time of the year when humidity contributions from corn sweat — the water drawn out of the soil by corn plants and released into the air through their leaves — are highest. Corn plans are tasseling and pollination is happening.

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The combined effect of the corn sweat and a heat dome, which will draw up hot and humid air from a warmer-than-average Atlantic Ocean in the South, to the Midwest, will exacerbate the risk for heat-related impacts in the Plains and Midwest, the Washington Post reports.

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Staying cool during the heat wave

The National Weather Service is encouraging Iowans to take precautions since heat-related illnesses can “increase significantly” during extreme heat and high humidity events.

“Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors,” NWS stated in notices about the extreme heat watch. “Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.”

To combat the heat, Linn County Emergency Management has announced that cooling centers around the county will be open for residents to go to when they need to get out of the heat and humidity.

According to the NWS, heat is the leading weather-related killer across the United States, with some people being more at-risk of heat stroke and heat exhaustion than others.

Some of those at higher risk include young children and infants, older adults, people with chronic medical conditions, and pregnant women.

The Washington Post contributed to this report.

Olivia Cohen covers energy and environment for The Gazette and is a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues. She is also a contributing writer for the Ag and Water Desk, an independent journalism collaborative focusing on the Mississippi River Basin.

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Comments: olivia.cohen@thegazette.com