Chicago Weather

Chicago weather: 100-degree heat index continues. Is it officially a ‘heat wave?'

Temperatures are expected to settle into the low-to-mid 90s for the rest of the week with even higher heat indices

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A long stretch of 90-degree days for the Chicago area continues Tuesday, the NBC 5 Storm Team said, with heat indices expected to reach between 95 degrees and 100 in some parts.

"Still very steamy," NBC 5 Meteorologist Alicia Roman said. "Very warm temperatures all around once again. No lake cooling."

Tuesday's predicted high temperature was expected to be 94 degrees. Monday's high temperature, 97 degrees, broke a record that stood for nearly 70 years, the National Weather Service said.

MORE: 4 easy and fast ways to cool your body down in extreme heat

Tuesday morning will also see isolated showers and storms, Roman said, with spotty showers lifting to the north through the morning hours.

By 9 a.m., the rain was expected to move out of the area, Roman said.

Isolated shower and storm chances were expected to continue throughout the week, timed with the heating of each day, Roman said, as more 90-degree readings and muggy conditions were expected to come.

Does that mean it's officially a heat wave?

Despite breaking a heat record Monday, the Chicago area did not see any heat advisories or excessive heat warnings or watches.

According to NBC 5 Meteorologist Kevin Jeanes, a heat advisory goes into effect when a heat index of between 105 degrees to 115 degrees is expected for up to three hours a day. A heat advisory would also go into effect if nighttime lows clock in at 80 degrees or higher for two days, Jeanes said.

An excessive heat warning goes into effect when heat indices of 105 degrees or more takes place for more than three hours a day for two consecutive days. It would also go into effect if the heat index hits 115 degrees at any time, Jeanes said.

Jeanes noted that a heat wave consists of a "period of abnormally and uncomfortably hot and unusually humid weather."

"Typically, a heat wave lasts two or more days," Jeanes said.

According to the NBC 5 Storm Team, the average high for this time of year is 81 degrees.

Sunday, the high temperature was 95 degrees and Monday's high was 97 degrees. Tuesday's predicted high, of 94 degrees, signal that conditions for the area are "abnormally hot," the NBC 5 Storm Team said, which means they qualify for a heat wave.

"This is a stretch of unusually hot weather for June, so we can call this a heat wave," Jeanes said."

While the 90s are set to continue, areas near the lake could see a reprieve from the heat Thursday and Friday, where temperatures are expected to cool off, the National Weather Service said.

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