Tropical Storm Arthur formed off the coast of Florida on Saturday, making it the sixth straight year for a named storm to develop before the official June 1 start of the Atlantic hurricane season.
The storm’s centre was located at 11 p.m., about 190 miles (305 kilometres) northeast of Cape Canaveral, Florida, the U.S. National Hurricane Center in Miami said. Arthur has top sustained winds of 40 mph (65 kph) and is moving to the north-northeast at 13 mph (20 kph), officials said.
A tropical storm watch remained in effect for parts of the North Carolina coast. Forecasts say Arthur will stay well offshore of Florida and Georgia on Sunday and then approach the North Carolina coast on Monday, where it will drop between 1 and 2 inches of rain Sunday night and Monday.
Dangerous coastal surf conditions and rip currents are expected to spread northward from Florida to the mid-Atlantic states during the next few days.
While there may be a component of warming waters and climate change in other pre-June storms, Arthur is more of a subtropical storm system than a traditional named storm and its water is cooler than what’s usually needed for storm formation, said Colorado State University hurricane researcher Phil Klotzbach.
A lot of these out-of-season storms are weak fleeting ones that meteorologists can see now because of satellites and better technology and would have been missed in earlier times, Klotzbach said.
Like most earlier-than-usual storms, Arthur is likely to remain offshore, but could come relatively close to North Carolina’s coast Monday, Klotzbach said.
Hurricane season officially starts June 1.
Local forecasters in the Bahamas said showers have lingered over the islands of Grand Bahama and Abaco, which are still struggling to recover after being hit by a Category 5 hurricane last year.
However, no flooding has been reported as the depression swirls just northwest of the archipelago and is expected to head into open ocean as it strengthens.
Officials said they were prepared to evacuate patients currently housed in tents in Grand Bahama after Hurricane Dorian damaged the island’s hospital, but forecasters said the bulk of thunderstorms are located north and east of the depression and are not expected to affect the region.
The tropical storm watch was issued for parts of North Carolina’s coast, from north of Surf City to Duck, including Pamlico and Albemarle Sounds.
Danica Coto in San Juan, Puerto Rico, contributed to this report