Even if Florence remains entirely at sea, the storm is likely to generate heavy seas and hazardous rip currents along the USA this weekend, the hurricane center warned. "This will likely be a big problem not just Thursday but potentially through the entire weekend". "During harvest, time is of the essence".
Although it is quite a distance away, swells generated by Florence will begin to impact the southeastern U.S., including Florida, today and through much of next week. On North Carolina's Outer Banks, Dare County emergency officials warned that rough seas and strong rip currents are already creating risky conditions.
Forecasters said rapid intensification is likely to begin by tonight and Florence is expected to become a major hurricane by Monday.
The NHC was also tracking two other storms farther out in the Atlantic.
"There is an increasing risk of two life-threatening impacts from Florence: storm surge at the coast and freshwater flooding from a prolonged heavy rainfall event inland". Beach officials have urged swimmers to take caution because of strong waves and rip currents.
Local impacts from Florence are not expected, according to the National Weather Service Tallahassee. An increase in forward speed is expected over the next couple of days.
The storm is moving towards the west at seven miles per hour, and is forecast to drench a large swath of the US East Coast running from northern Florida to New Jersey.
Hurricane Florence is to hit the east coast later late this week and has become a major hurricane. McMaster emphasized that there's no way to know yet when and where the storm will hit land, or when evacuations might be called.
Tropical Depression Nine formed 1755 miles east of the Windward Islands Friday.
Hurricane Isaac is holding steady in strength over the Atlantic. At this point in time, it is too soon to determine whether or not Isaac is a threat to the U.S. Some of the more reliable models show it moving westward through the Caribbean later in the week.
NHC forecasters have flagged a cluster of thunderstorms in the western Caribbean for the possibility of development, giving it a 40 percent chance of formation within the next five days as it moves into the Gulf of Mexico.