Dangerous Heat Hitting the Chicago Area on Thursday, Friday

Video: Joining “Chicago Tonight” is Mark Petri, director of the electric power grid program at Argonne National Laboratory. Petri coordinates research to improve the reliability, resiliency, security and efficiency of the nation’s power grids. (Produced by Paul Caine)

Parts of the Chicago area are under excessive heat warnings and heat advisories Thursday with temperatures expected to top out at 96 degrees along with a heat index into the triple digits, according to the National Weather Service.

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The heat index, or what temperatures can feel like when combined with humidity, is expected to reach up to 111 degrees in some parts of the state Thursday with cooler conditions near Lake Michigan due to onshore winds.

NWS is reminding people to take precautions if spending time outdoors as dangerous heat conditions are expected for the rest of Thursday and Friday.

Potential thunderstorms Friday might provide some relief from the heat, according to the weather service. Temperatures on Friday are expected to reach 97 degrees with a heat index of 112 degrees.

Around 150 million people are currently experiencing heat alerts amid scorching temperatures across the country. 

The extreme weather is putting increasing demands on the nation’s power grid.

On Thursday, the country’s largest grid operator, PJM Interconnection, issued an alert that it may have to implement emergency procedures amid soaring demand for power.

PJM operates in multiple states, including Illinois.

“What I’m hearing is that they’re running really close to their margins,” said Mark Petri, director of the electric power grid program at Argonne National Laboratory, where he coordinates research to improve reliability, resiliency, security and efficiency for America’s power grids. “Under typical circumstances the power grid is run with extra capacity kept in reserve, but with the increase in air conditioning on the demand side and the limitations that happen on the power grid side because of rising temperatures, they feel that they are really cutting into those margins.”

Petri said things should be fine but there is little redundancy left in the system.

What that means is that “if there is any other event that takes place — one or more power plants goes down, a circuit-breaker trips or a sub-station goes out or some combination of these things — it could require power grid operators to shed load and start with brownouts or rolling blackouts,” Petri said.

In extreme heat conditions, Chicago officials advise people to stay hydrated, wear sunscreen, stay out of the sun and avoid strenuous outdoor activities.

Signs of heat-related illness include dizziness, thirst, heavy sweating, nausea and weakness.

Young children, infants, older adults, people with chronic medical conditions and pregnant people are particularly vulnerable to heat-related illness and death.

Click the following links for more guidance about heat-related precautions and how to find a cooling center in Chicago and Cook County.

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