Forecasters say it's still too soon to say when and how powerful Hurricane Isaias will be when it reaches northeastern North Carolina. But the potential is increasing, they say, for the storm to bring tropical force winds and heavy rainfall and cause coastal flooding when it arrives.

On Saturday, Hurricane Isaias snapped trees and knocked out power as it blew through the Bahamas and churned toward the Florida coast. It had slowed down late Saturday afternoon and weakened into a tropical storm but was expected to regain hurricane strength overnight as it neared Florida.

The National Weather Service in Wakefield, Virginia, said Isaias will approach Florida's east coast Saturday night through Sunday. The first regional impacts from the storm will be increased swells and rip currents on the coast late Sunday, the NWS said.

The threat of the region seeing tropical force winds of 58 mph is increasing, particularly along the coast and in coastal waters, the NHS said. Those tropical winds could arrive as early as Monday evening. However, the "most likely" time the immediate region might see those winds is sometime Monday night and continuing into Tuesday afternoon, the NHS said.

The Outer Banks and the Virginia coast have the highest chance of seeing winds above 58 mph, the weather service said. State officials, however, are preparing for impacts from sustained winds of 70 mph on Monday. Gov. Roy Cooper's office said Saturday the areas most at risk are those along Interstate 95 and eastward. 

The region could see between 2 and 5 inches of rain from Isaias, with some areas possibly seeing higher amounts. The weather service cautioned that areas at highest risk of heavy rainfall could change if the storm's track and intensity change. 

With Isaias increasing the risk of dangerous rip currents late Sunday, the NHS warned of dangerous surf conditions continuing into early next week.

There is also the potential for moderate flooding along the coast of Virginia and northeastern North Carolina Monday night into Tuesday, the NHS said. The potential threat of tornadoes is also elevated anywhere across the region Monday night into Tuesday, the NHS said.

Local and state officials were already ramping up their storm preparation response.

As of mid-day Saturday, local officials had ordered evacuations for Hatteras and Ocracoke Islands, Ocean Isle Beach and Holden Beach. 

Cooper also authorized the activation of up to 150 members of the North Carolina National Guard to be used if needed in hurricane response, and water rescue teams are preparing to respond if they are needed.  

As the storm moved toward Florida on Saturday, a hurricane warning was in effect from Boca Raton to the Volusia-Flagler county line, which lies about 150 miles north. A hurricane watch was in effect from Hallandale Beach to south of Boca Raton. A hurricane warning means that hurricane conditions are expected somewhere within the area, and a watch means they are possible.

The weather service advised residents to continue to monitor or for the latest information.