An NOAA Hurricane Hunter plane investigating Florence found that its winds had increased to 130 miles per hour late Monday morning. He estimated that about one million people will be affected by order, including residents and visitors. Olivia should weaken through Tuesday but remain a strong tropical storm when it reaches the Hawaiian Islands.
And the timing couldn't be more apt: Monday is the peak of the Atlantic hurricane season, when storm activity is historically at its highest.
Of the five hurricanes and two tropical storms spinning in the Atlantic and Pacific right now, Category 4 Hurricane Florence is the most powerful.
Hurricane Florence, which was barely a Category 1 hurricane 24 hours ago, is now a Category 3-and it continues its steady advance toward the eastern seaboard. But communities along the North and SC coast will likely see storm surge and damaging winds as Florence comes ashore.
"We here in North Carolina are bracing for a hard hit", Cooper said during a press conference outlining the state's preparations. Even in areas far from the coast, he added, parts of North Carolina and Virginia could see rain totals of 10-15 inches over the next seven days. "Somewhere along the Carolinas will see a surge, we just don't know where yet", he said. Some 27 percent of the deaths have come from rain-driven flooding, sometimes hundreds of miles inland.
Navy ships off Virginia's coast were preparing to sail out of the path, a North Carolina university has already canceled classes and people have begun stocking up on plywood, bottled water and other supplies.
CNN's forecasters warn that Florence could be the strongest and most devastating hurricane to hit North and SC in about three decades.
Accuweather's Alex Sosnowski noted that the storm will also affect the mid-Atlantic region. The US also has the Hurricane Weather Research and Forecasting (HWRF), which uses real-time data from aircraft and satellites to monitor changing weather conditions faster than the scientific models.
Florence is the first major hurricane to threaten the eastern United States this year as the Atlantic hurricane season hits its peak. Forecasters said Hurricane Helene was strengthening far from land over the open Atlantic, centered about 375 miles (600 kilometers) west of the southernmost Cabo Verde Islands.
Helene is now located in the tropical Atlantic, off the west coast of Africa.