Here's what you need to know now about the powerful storm that forecasters say is gaining strength:
• The storm has already killed at least 28 people in several Caribbean countries.
• Authorities urged more than 2 million people to leave their homes in coastal Florida, Georgia and South Carolina as the storm neared -- the largest mandatory evacuations in the United States since Hurricane Sandy hit the East Coast in 2012.
• Based on the latest projections, Matthew could make landfall in Florida early Friday as a Category 4 hurricane. It could also skirt the coast as it continues north. Outer rain bands from the storm are already approaching Florida.
• It's moving northwest at about 12 mph and packing 125 mph (205 kph) winds -- a Category 3 storm. Thursday morning it was about 30 miles (45 km) south-southwest of Nassau, Bahamas, and 215 miles (350 km) from West Palm Beach, Florida.
• Florida Gov. Rick Scott offered a dire warning Thursday morning for people living in evacuation zones: "This is serious. ... Don't take a chance. A small movement (of the storm) could mean a lot. That's why we have to prepare for a direct hit. So again, if you need to evacuate and you haven't, evacuate. This storm will kill you. Time is running out. We don't have that much time left."
• "This could be an extremely disastrous hurricane for so many large areas where so many people can be affected," National Hurricane Center Director Rick Knabb told CNN Thursday. "It's not just going to come ashore and affect a narrow zone and then move on. It's going to be going up the coast and could remain a major hurricane at the coast, or very close to it, the whole way up. That's awful."