MARIETTA — Cobb was expected to go from a foggy Christmas day to overnight thunderstorms with a threat of tornadoes. But one person has already died in an accident that police said could have been impacted by the weather.

An accident Monday night in Smyrna that involved two Toyota Camrys was fatal for Luca Kosic of Marietta. Kosic was pronounced dead at the scene of the accident at Smyrna Powder Springs Road and Trellis Oaks Drive by the Cobb County Medical Examiner’s Office, Cobb Police said.

The preliminary investigation shows a maroon 1994 Camry, driven by Huy Q. Tran of Austell, 39, traveling northbound on Smyrna Powder Springs Road and veering to the left for an unknown reason, crossing over the double yellow line partially into the southbound lane, police said. The vehicle then collided with a gold 1999 Camry, which was travelling southbound, driven by Mara Tadic, 49, of Acworth.

Both drivers were transported to WellStar Kennestone Hospital, where they were treated for minor injuries.

Also treated for minor injuries at Kennestone were Andeiko Tadic, 23, and Angelina Tadic, 27, both of Acworth, and a 16-year-old from Marietta who was not identified because the person is a juvenile. Like Kosic, they were all passengers in the 1999 Camry.

Investigators believe extreme dense fog was a contributing factoring the collision.

Cobb Police spokesman Officer Mike Bowman said that in foggy and wet conditions, motorists should turn their lights on, slow down and be aware of other drivers.

The weather wasn’t expected to improve much overnight, said meteorologist Mike Leary with the National Weather Service in Peachtree City. While tornadoes were more likely south of Interstate 20, much of northwestern Georgia was expected to see damaging winds, possible hail and rainfall between one and two inches with localized flooding.

The worst of the weather was expected between midnight and 6 a.m. After that, Leary doesn’t expect any problems.

“It’s going to be a real quick blast, and after that, it’s going to be great for the rest of the week,” he said.

The National Weather Service calls for highs in the upper 40s and low 50s through Friday, with sunny skies Thursday and Friday.

As of late Tuesday afternoon, no problems with power outages were experienced in Cobb.

“At this point, we’ve got less than 100 customers out statewide,” Georgia Power spokeswoman Carol Boatright said.