Weather experts say Central Illinois is sweltering as a “heat dome” passes through the area, with temperatures peaking on Tuesday.
Meteorologist Ed Shimon from the National Weather Service’s Lincoln office said the heat index Tuesday is expected to reach as high as 115 degrees. The culprit behind the scorching temperatures is the dew point, or the measure of moisture in the air.
“Right now [Monday], our dew points are in the 60s, which is generally in the uncomfortable range,” Shimon said. “And then, once you get dew points in the 70s, it starts to create a situation where, you know, the air, once it gets into air temperature in the 90s and dew points in the 70s, can combine to put heat indices over 100 degrees.”
These extremely high temperatures follow relatively cool mornings and evenings last week. Shimon said the reason for the change is what’s known as a “blocking pattern.” The aftereffects of Hurricane Debby on the east coast of the U.S. sent a cooler air mass in our direction last week. Now, that cooler air has cleared and a dome of heat and moisture out of the southwest is moving in to take its place.
“It’s just kind of a progression that occurs as the air mass gradually changes when it moves from one region to another,” Shimon said.
Shimon expects temperatures in the high 90s and low 100s to stick around until Friday. Until then, he recommends avoiding exposure to the heat as much as possible. Prolonged exposure can lead to heat exhaustion and ultimately heatstroke.
If you do have to travel or work outside, Shimon said light clothing, diligent hydration and frequent breaks are key.
Fortunately, there’s a possibility this is our last heatw ave of the summer. But, Shimon said history shows that might not be.
“One year, I think it was 2011, the first three days of September were over 100 degrees in Springfield,” he said. “It was like 102, 101 and 100 to September first, second and third. So, you know, it’s not out of the question to have 100-degree heat in September.”
