CHICAGO (CBS) — You might have hoped the surprise hailstorms that swept through the Chicago area Thursday evening would mean a surprise cold front had also come through, and the sweltering heat forecast for Friday wouldn’t happen.

No such luck. The forecast remains the same, with highs in the upper 90s and heat indexes even topping 100 degrees in some areas.

And in all seriousness, the heat can be dangerous, and Chicagoans are strongly advised to take precautions.

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CBS 2 Meteorologist Megan Glaros says the forecast high for Friday remains 95 to 97 degrees. But conditions will be humid and sticky, and the heat index will make it feel like it’s 100 to 105 degrees. The record for July 1 is 103, set in 1956.

A heat advisory is in effect for all Chicago area counties from noon to midnight, and the city’s Office of Emergency Management and Communications is advising everyone to be safe.

In particular, the OEMC advises people to watch out for signs of heat stroke. Signs of the dangerous condition are an extremely high body temperature that would be as severe as a bad fever – such as 103 degrees or above – as well as dizziness and nausea, a throbbing headache and a rapid, strong pulse, and skin that is red, hot and dry.

Anyone suffering from heat stroke needs immediate attention. If you see anyone with heat stroke, the OEMC says you should call 911 right away, then move the person to a cool place and provide water.

Everyone is also advised to drink at least eight glasses of water a day, avoid going out in the hottest part of the day, take an occasional cool bath or shower to reduce body heat, wear light, loose-fitting clothing and a hat to protect your head, limit pets’ exposure to heat and keep them hydrated, and check on friends, relatives and the elderly who may be at risk.

All Chicago Police stations, libraries and public buildings are open as temporary cooling centers. Information is also available on cooling centers at the city’s six Community Service Centers by calling 311.

Also, the city is asking people not to open fire hydrants, because they decrease water pressure and can prevent firefighters from being able to use them if there is a fire.

While it may not seem like it, 100-degree days like we might see on Friday are rare in Chicago. The last time the temperature in Chicago topped 100 degrees was in 2005.

And we all remember the dangers 100-degree temperatures can bring from a horrific heat wave a decade before that. The heat wave in July 1995 was blamed for 739 deaths.

The good news for the sweltering heat coming Friday is that it will only last one day. A cold front comes in on Saturday, cutting temperatures back down to the low 90s or even upper 80s.

But the overnight low for Friday night is 75 degrees, so if you’re planning on an early-morning run on Saturday, it might be best to do it on the track at the gym rather than outside.

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