Fireworks and grills aren’t the only things that will sizzle in Suffolk today.

With temperatures expected to strike the mid-90s and heat indexes hitting triple digits for the second day in a row, Suffolk residents need to exercise caution when going to outdoor July Fourth festivities today.

&uot;I’d encourage people to have their activities early in the morning or late at night,&uot; said Capt. Jim Judkins, the city’s emergency service coordinator. &uot;Drink plenty of liquids – and I mean non-alcoholic liquids –

and try to stay out of the midday sun. That’s the hottest part of the day.

&uot;People should try to spend as much time in front of a fan or air-conditioner or under a shade tree as much as possible today.&uot;

By 10 a.m. Wednesday, the National Weather Service issued heat advisories that runs through Friday for the Hampton Roads area. The advisory reported that the heat index – which combines the temperature and the humidity – could soar up to 110 degrees today.

The combination of heat and automobile emissions produced dangerous ozone levels in the state’s most congested regions Tuesday, and similar levels were possible by Wednesday afternoon as more people hit the road for the holiday, state Department of Environmental Quality meteorologist Dan Salkovitz said.

High levels of ozone, the main pollutant in smog, can impair breathing and put additional strain on the heart. The elderly and people with respiratory illnesses are especially at risk.

Salkovitz said the ozone level in traffic-choked northern Virginia hit the rare and extremely unhealthy &uot;code purple&uot; level Tuesday. Hazardous ozone levels resulted in a code red alert in Richmond.

On Tuesday, Suffolk, like the rest of Hampton Roads, registered a code orange, which means ozone levels were unhealthy for people who are susceptible to respiratory problems.

&uot;We’ve had high readings this week across the northeast corridor and all the way to North Carolina,&uot; Salkovitz said.

The weather forecast for Thursday calls for a chance of thunderstorms, which &uot;would help the situation significantly,&uot; Salkovitz said. Cooler temperatures on Friday also should help, he said.

Cars also have been affected by the heat. Randy Green, spokesman for AAA-Mid Atlantic in Richmond, reported a significant increase this week in calls to the auto club’s emergency service center.

&uot;It’s a combination of overheated cars and cars with overtaxed electrical systems,&uot; Green said Wednesday.

He said that in hot weather and heavy traffic it’s even more important than usual to make sure your car is in top running condition. That means maintaining proper antifreeze and oil levels and making sure tires, belts and hoses are in good shape.

Green also said motorists should keep a close eye on their car’s heat gauge, shutting off the air conditioner and rolling down the windows if the car starts to run too hot. He said cell phones and other accessories should be unplugged to lessen the drain on the car’s battery.

It’s also a good idea to carry a supply of water, both for drinking and for adding to the radiator if the car overheats, Green said.

According to AAA, more than 36.7 million Americans are expected to travel 50 or more miles from home this Fourth of July.

The Associated Press contributed to this report.