Sept. 14 (Bloomberg) -- Hurricane Ophelia may reach the southeastern U.S. coast as early as this afternoon as the storm regained hurricane strength amid warnings and evacuations along parts of North and South Carolina.

The winds increased late yesterday to 75 miles per hour (120 kph), the threshold for a hurricane, and was centered about 115 miles east of Charleston, South Carolina, and 110 miles south of Wilmington, North Carolina, at 11 p.m. local time. Ophelia was stationary at that time.

The outer bands of the storm, which has been upgraded four times, brushed the coast late last night. Ophelia may reach the coast between noon and late evening today, according to the Miami- based National Hurricane Center. The slow movement suggests Ophelia's winds and rain may last 36 to 48 hours.

``The prolonged nature of the storm could increase the threat of coastal erosion,'' Eric Blake, a hurricane center meteorologist, said yesterday.

Ophelia follows less than two weeks after Hurricane Katrina swept ashore Aug. 29, devastating the Gulf of Mexico coast in Louisiana, Mississippi and Alabama, and flooding New Orleans. The government approved $62.3 billion in relief for the areas, making Katrina the most expensive disaster in U.S. history.

South Carolina Governor Mark Sanford said in an interview last night on MSNBC that 280 National Guard troops were stationed along the coast in preparation for Ophelia.

States Prepare

A hurricane warning, meaning hurricane conditions are expected within 24 hours, was in effect from South Santee River in South Carolina to Oregon Inlet. A hurricane watch, which means conditions are possible within 36 hours, was extended north to the Virginia border.

North Carolina ordered mandatory evacuations in low-lying, flood-prone areas of six coastal counties and voluntary evacuations in parts of others. The University of North Carolina Wilmington and East Carolina University in Greenville canceled classes for tomorrow, CNN reported on its Web site.

North Carolina Governor Mike Easley said residents along the coast should prepare for a storm that could cause several days of widespread flooding, block roads and power outages, according to the state Web site.

Ophelia was expected to bring an additional 4 inches to 8 inches of rain in parts of the Carolinas, with a maximum total of 15 inches along North Carolina's coast, the hurricane center said. Isolated tornadoes were possible today along North Carolina's coast, the agency said.

Easley said at least 30 shelters were open, and 350 National Guard troops were activated, CNN reported. Virginia Governor Mark Warner declared a state of emergency earlier this week.

Ophelia is the 15th named storm of the June 1-Nov. 30 Atlantic hurricane season and was a Category 1 hurricane yesterday before being downgraded to a tropical storm. Hurricanes are measured on the five-step Saffir-Simpson scale, with Category 1 the weakest.

To contact the reporter on this story: Jessica Brice in San Francisco at jbrice1@bloomberg.net

Last Updated: September 14, 2005 00:21 EDT