Gov. Nathan Deal encouraged residents of six coastal Georgia counties to evacuate on Wednesday as Hurricane Matthew charted a course toward the Atlantic coast, warning that torrential rainfall and strong winds could cause widespread damage along low-lying areas.

The governor also expanded a state of emergency to 17 more southeast Georgia counties and signed an executive order to temporarily lift restrictions on trucks shipping key supplies to Georgia’s coast. Thirty counties are now covered by his emergency order.

In a statement late Wednesday, Deal urged the residents of Chatham, Bryan, Liberty, McIntosh, Glynn and Camden counties to evacuate. But he stopped short of making it a mandatory order.

Forecasters predict the storm, which ravaged Haiti Tuesday and battered the Bahamas Wednesday, could slam into Florida’s Atlantic coast by Friday and then rake Georgia and South Carolina. Local officials earlier ordered roughly 30,000 residents in Tybee Island and other low-lying coastal communities to evacuate.

Asked Tuesday what might trigger a broader evacuation order from the state, Deal said: “That’s left up to Matthew.”

Florida Gov. Rick Scott warned the state could be facing its "biggest evacuation ever" as he urged millions of coastal residents to prepare. And South Carolina Gov. Nikki Haley outlined plans to evacuate more than 1 million people on the coast. Some highways in southeast Georgia were jammed with commuters.

Jim Butterworth, the emergency agency’s chief, said Tuesday that state officials are ready to reverse lanes on I-16 if a large-scale evacuation is necessary. State officials are mindful of what happened in South Carolina in 1999, when emergency officials didn’t reverse the lanes on Interstate 26 and a two-hour trip from Charleston to Columbia took some drivers an entire day.

The governor and Butterworth also urged residents in coastal areas to stock up and keep close track of the storm’s path, which can defy forecaster predictions.

"I urge Georgians in the affected areas to remain calm, be prepared and make informed, responsible decisions as we continue to monitor Hurricane Matthew’s path,” Deal said.