Here’s when Tropical Storm Isaias’ winds and rain could arrive in Beaufort County

Winds and rain from Tropical Storm Isaias are forecast to arrive at the earliest about 10 a.m. Monday in Beaufort County, according to the National Weather Service Charleston’s forecasts.

The latest forecast shows the storm coming close to the Charleston County coastline Monday evening as a low-end hurricane or high-end tropical storm, NWS Meteorologist Ron Morales said during a weather briefing Sunday afternoon.

“Don’t play this down, hearing ‘tropical storm,’” Morales said.

Beaufort County was already seeing rip currents and waves about two to four feet along beaches, including Hilton Head, where beachgoers were encouraged to stay out of the water, weather service officials said Sunday morning.

Tornadoes and storm surges are a low risk for Beaufort County Monday.

As of 2 p.m. Sunday, Tropical Storm Isaias sat about 45 miles east southeast of Vero Beach, Florida, moving north-northwest at about 9 mph.

Maximum sustained winds near 65 mph were recorded.

“Some fluctuations in strength will be possible during the next 48 hours,” a National Hurricane Center report says.

The tropical force winds are extending about 115 miles from the center.

A tropical storm warning was in effect Sunday from Jupiter Inlet, Florida, to Surf City, North Carolina, including all of South Carolina’s coast.

A tropical storm warning means storm conditions are expected within 36 hours, according to the NHC.

Tropical storm winds

The earliest onset of tropical storm-force winds is forecast for about 10 a.m. Monday, Meteorologist Brittany MacNamara said Sunday.

She said the coastline could see gusts up to 70 mph and sustained winds of 40 to 50 mph.

The winds will rapidly decrease inland, she said. Sustained winds inland could be about 25 to 30 mph.

Sustained winds between 39 and 73 mph are considered tropical storm force, according to the National Weather Service.

Sustained winds must reach 75 mph to be considered a Category 1 hurricane, according to the Saffir-Simpson Hurricane Wind Scale.

The Charleston area has a 10-20% chance of seeing hurricane-force winds later in the day, Morales said.

He added that there is a six- to eight-hour window for when winds could arrive on the South Carolina coast.

Rain

The Beaufort County area could see between two to four inches of rain, with isolated areas seeing up to six inches, MacNamara said.

Heavy rain will likely start about the same time as the wind — late morning, she said.

“You could get a few scattered showers breaking off from the bands,” MacNamara said, and they could show up earlier in the area.

There is a potential for minor flooding from Georgia to the Charleston area from rain, Morales said.

He said Charleston is likely to see the largest threat of heavy rainfall, with flooding more significant if landfall happens with the evening high tide.

Storm surge

The National Weather Service forecast a potential storm surge of one to three feet from Ponte Vedra Beach to Edisto Beach.

MacNamara said Sunday that the forecast shows storm surge possible of about one to two inches in the Beaufort County region along the coast and waterways.

The potential for storm surge could be seen Monday afternoon into the evening, Morales said.

Tornadoes

The National Hurricane Center warns of a potential for tornadoes along the South Carolina coast and ahead of and during the storm.

Morales said that chance is greatest around the Charleston area.

Georgia and the coastline south of Charleston have a much lower risk of tornadoes, he said.

Georgia could see that threat starting late Sunday and early Monday. South Carolina’s risk is through Monday.

This story was originally published August 2, 2020 at 1:36 PM.