"The Worst is Still to Come." Florida Gov. Rick Scott, on Hurricane Matthew

NBC News, Friday Morning 10/7: Hurricane Matthew is leaving a trail of damage along Florida as it continues to bear down on the eastern side of the state Friday, and Florida's governor warned the worst could is still likely to come.

"We are very concerned about storm surge and the worst effects are still likely to come," Gov. Rick Scott said in a press conference Friday morning.

The storm left more than 590,000 people without power, as of 9 a.m. ET on Friday.

Additionally, airlines have cancelled 4,482 flights that were scheduled to occur Wednesday through Saturday due to the storm, which had been as strong as a Category 4 hurricane before weakening to a Category 3 overnight.

Damage assessments are just beginning for Florida. Heritage Insurance Holdings estimated losses from the deadly could be about $500 million.As Hurricane Matthew strengthened overnight, the super powerful hurricane hit the Bahamas with winds exceeding 100 miles per hour. Weathermen considered the possibility the storm could hit the US twice

Matthew intensified at 6 am EST, and unprecedented damage is possible. For 24 to 36 hours, the storm could hit anywhere along the Florida Atlantic coast. It will then probably track up through the US East coast. The storm is so strong that even the West coast of Florida was warned to expect flooding from rain.

1.5 million people fleed south Atlantic coastal areas as Hurricane Matthew regained strength as a Category 4 storm Thursday and eyed the United States.

The storm, which had dipped to a Category 3, roared back up Category 4 late Thursday morning, with maximum sustained winds at 140 mph, the National Hurricane Center said. "Extremely dangerous Hurricane Matthew heading for Florida," the Hurricane Center warned in its 11 a.m. advisory.

Evacuations were under way in Florida, Georgia and South Carolina after Matthew, which hammered Haiti and strafed Cuba, began battering the Bahamas. The storm killed 25 people in the Caribbean, mostly in Haiti, and forecasters warned of "life-threatening" devastation as it crossed the Bahamas.

State officials in Florida, South Carolina and Georgia cautioned residents not to hunker down at home if they live in the hurricane's potential path.

Not all of the millions of people in Matthew's path have been ordered to leave, but the mandatory evacuations are the largest since Hurricane Sandy struck the East Coast from North Carolina to New York in 2012.

Early Thursday the hurricane, which already has killed at least 15 people in several Caribbean islands, was about 60 miles (95 kilometers) southeast of Nassau, Bahamas, and 255 miles (410 kilometers) from West Palm Beach, Florida.

The National Hurricane Center isn't saying that Matthew will make landfall in Florida, but that the center of the storm will get "very near" the Atlantic Coast, possibly as a Category 4 hurricane.

Matthew was packing 125 mph (205 kph) winds as the eye neared the northwest Bahamas, the National Hurricane Center said.

President Barack Obama warned Americans in the storm's path to pay attention and take any evacuation orders seriously. He said if the core of the storm strikes Florida, it could have a "devastating effect."

Florida Governor Scott has repeatedly warned that a direct hit by Matthew could lead to "massive destruction" on a level unseen since Hurricane Andrew devastated the Miami area in 1992. He has activated 1,500 National Guard members in preparation for the storm.

The voluntary and mandatory evacuations currently stretch from the Miami area all the way north to the Florida-Georgia border.

St. Johns County officials ordered 14,000 residents in St. Augustine, the oldest city in the US, to evacuate ahead of Hurricane Matthew starting at 6 a.m. ET Thursday.