Forecasters issued a hurricane watch for the South and North Carolina coasts Thursday as Tropical Storm Ernesto gained strength over the Atlantic Ocean. The hurricane watch means hurricane conditions, with sustained winds of at least 119 kilometers per hour (kph), are possible within 12 hours. For residents who long have weathered hurricanes in the region, Ernesto s wind was less of a concern than the threat of flooding. Thunderstorms have been drenching North Carolina for more than a day, and Ernesto could bring 15 centimeters of rain. Ernesto had been downgraded to a tropical depression over Florida, but gained strength and was upgraded as it moved over the warm Atlantic waters. Its outer bands reached the South Carolina coast Thursday morning, and its sustained wind was near 97 kph at midday. The storm was forecast to be over land late Thursday along South Carolina s coast before heading for central North Carolina, where its winds would weaken but its rains would continue. Hundreds of National Guard troops are on alert, and officials in the Carolinas warned residents to be prepared. We know we re gong to get a lot of rain, we know this is going to be a water event, North Carolina Governor Mike Easley said.