In Jacksonville, North Carolina, officials had rescued more than 60 people overnight from a hotel that was collapsing in the storm.
Cooper also announced there are 2,800 National Guard troops in different staging areas of North Carolina.
Forecasters said that given the storm's size and sluggish track, it could cause epic damage akin to what the Houston area saw during Hurricane Harvey just over a year ago, with floodwaters swamping homes and businesses and washing over industrial waste sites and hog-manure ponds. On top of that, a disastrous amount of rain - 500mm, possibly even as much as 1m - is expected to fall. The NHS warned of "catastrophic" flash flooding from rainfall totals as high as 40 inches. "Hurricane-force winds extend outward up to 80 miles (130 km) from the centre and tropical-storm-force winds extend outward up to 195 miles (315 km)".
Florence's winds had dropped from a peak of 225 kph to 165 kph by midmorning, reducing the hurricane from a Category 4 to a Category 2.
"The larger and slower the storm is, the greater the threat and impact, and we have that here", NHC Director Ken Graham said on Thursday.
It's estimated as many as 3 million homes and businesses in North and SC could lose power after Hurricane Florence drives into the coast, leaving much of the region in darkness for weeks. "Don't plan to leave once the winds and rains start".
The center of Florence will approach the coasts of North and SC later on Thursday, then move near or over the coast of southern North Carolina and eastern SC in the hurricane warning area on Thursday night and Friday, the NHC added.
The National Hurricane Center's best guess was that Florence's eye would blow ashore as early as Friday afternoon around the North Carolina-South Carolina line.
The storm's forward motion has slowed 11km/h since Wednesday (local time), which was predicted as the storm nears the coast.
Even though Florence is moving to the northwest at this time, AccuWeather meteorologists believe that the hurricane will stall and meander near the Carolina coast from Thursday night to Saturday.
Hurricane Florence began to inundate Frisco in North Carolina's Outer Banks on September 13. The list of canceled football games included No. 13 Virginia Tech's home game against East Carolina, No. 14 West Virginia's trip to North Carolina State and No. 18 UCF's visit to North Carolina. Of course, coupled with what could be tropical storm force wind gusts arriving as early as late tonight, there will likely be some trees knocked down as soils become quickly saturated.
Because landfalling hurricanes commonly spawn twisters, a tornado watch was issued for eastern North Carolina. Millions were expected to lose power, perhaps for weeks. That's down from a high of 140mph, but still expected to cause "life-threatening storm surge and rainfall".
Storm chaser Jeff Piotrowski tweeted at around 1:30 p.m. that storm surge slammed North Topsail beach. The hurricane is now centered about 220 miles (354km) east of Myrtle Beach, South Carolina, and 170 miles to the south-east of Wilmington, North Carolina. "From the storm surge alone, tens of thousands of structures are expected to be flooded in North Carolina".