Dangerous Heat, Storms Before 'Pneumonia Front' In Illinois

ILLINOIS — Dangerous heat and humidity is expected Tuesday, as heat index values could approach 110 degrees in some areas, according to the National Weather Service.

A heat advisory has been issued from noon to 8 p.m. Tuesday for McHenry, Lake, Ogle, Lee, DeKalb, Kane, Winnebago, Boone, DuPage, La Salle, Kendall, Grundy, Kankakee, Livingston, Iroquois, Ford, Cook and Will counties.

The weather service said to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.

In addition to the heat, there is also a threat for severe weather on Tuesday. AccuWeather is calling for a heavy thunderstorm in the late afternoon; and storms could bring flash flooding and damaging winds.

The weather service said the main threats with storms would be damaging winds up to 70 mph and damaging hail late Tuesday afternoon through the late evening hours. A flood watch has been issued from 2 p.m. Tuesday through late Tuesday night for Winnebago, Boone, McHenry, Lake, Kane, DuPage, Cook and Will counties.

The weather service said storms are likely to develop Tuesday afternoon, and could produce extremely heavy rainfall, with totals of 3 inches of rain in less than two hours.

A "pneumonia front" will bring "sharply cooler" temperatures, possibly a 20-degree drop, to areas near Lake Michigan on Tuesday afternoon, according to the weather service. Temperatures will fall into the 70s in those areas near the lake.

The high on Wednesday will be near 80 degrees after the cold front moves in, according to the weather service forecast. Storms are also expected on Wednesday and Thursday.