Summer is set to make a big entrance in the United States this week, bringing a heat dome that will lead to sweltering temperatures and muggy conditions for millions. The upcoming weekend will be of particular concern for areas spanning Nebraska, Illinois, Wisconsin, and Iowa, where extreme heat is expected. Meteorologist Tom Kines from AccuWeather noted that this will mark the first true taste of summer for many residents from the Midwest to the East Coast. The high humidity will make temperatures above 90 degrees Fahrenheit feel even hotter by up to 20 degrees, according to Kines.
A heat dome forms when a large area of high pressure in the upper atmosphere traps heat and humidity, explained National Weather Service meteorologist Ricky Castro. The forecast predicts daytime temperatures in the 90s Fahrenheit and overnight temperatures in the mid-70s Fahrenheit from the Great Lakes to the East Coast throughout the heat wave expected to extend into next week. The humid conditions are being fueled by moisture coming from the Gulf of Mexico, a common occurrence during late spring and summer, said meteorologist Jacob Asherman.
The heat wave is expected to persist into the following week, with Denver possibly hitting 100°F on Friday and Chicago reaching 96°F on Sunday. Washington, D.C., and New York City could see temperatures in the upper 90s as well. Several Midwest states are at risk of dangerous temperatures over the weekend, with parts of Nebraska, Kansas, Iowa, Wisconsin, Missouri, and Illinois under the highest category for potential health risks due to the extreme heat.
High humidity levels make it difficult to cool down as sweat evaporates more slowly, leading to increased heat index values. It is important to take precautions during extreme heat by minimizing sun exposure, wearing light and loose clothing, staying hydrated, and seeking air-conditioned environments. Dry heat regions like Phoenix, Arizona, have lower humidity levels, allowing sweat to evaporate more efficiently compared to humid climates.
According to research from Johns Hopkins University and Johns Hopkins Health System, it can be easy to underestimate the extent of dehydration you may be experiencing. In places like Iowa, the crops themselves contribute to the humidity levels during the summer months through a process known as “corn sweat.” This occurs when plants transfer water to their leaves and surfaces for evaporation. While this phenomenon can make conditions feel somewhat like a sauna in the cornfields, the overall impact on humidity is minimal compared to moisture brought in by winds from the Gulf, as noted by the Ohio State University. Farmer Ryan Marquardt from Madison County, Iowa, describes the effect as similar to a sauna, with the added humidity causing increased sweating. This report includes contributions from Associated Press writer Jack Dura in Bismarck, North Dakota. The Associated Press’ coverage on climate and environmental issues is supported by various private foundations, with AP maintaining full responsibility for the content. For more information on AP’s standards when collaborating with philanthropic organizations, as well as a list of supporters and coverage areas, visit AP.org.
