Tropical Storm Beryl gained strength as it closed in on the southeastern U.S. coast on Sunday, dumping rain and whipping up heavy surf from northeastern Florida to South Carolina. The second named storm of the 2012 Atlantic hurricane season was approaching hurricane strength ahead of an expected landfall early Monday, the U.S. National Hurricane Center said. The powerful pack of thunderstorms has unleashed tropical storm conditions along the coast in northern Florida and Georgia, disrupting Memorial Day weekend plans for travelers and some beachgoers. At 11 p.m. EDT (0300 GMT), Beryl had sustained winds near 70 miles per hour (112 kph) and was located about 75 miles (121 km) south south-east of Brunswick, Georgia, the hurricane center said. An increase in wind speeds to 74 miles per hour (119 kph) or more would make it a Category 1 hurricane on the five-step Saffir-Simpson intensity scale. Forecasters, however, say they do not expect a significant change in Beryl\'s strength before it comes ashore and predict it will weaken to a depression by Monday night. Beryl was moving west toward the U.S. coast at 10 mph (16 kph), with tropical storm force winds near the coast of northeastern Florida. The storm\'s approach led some vacationers in Georgia to leave early, said Alden Alias, the front desk manager at The King and Prince Hotel on St. Simons Island, a popular coastal resort town. \"The waves are pretty big,\" she said. \"The winds are starting to pick up.\" City officials in Jacksonville canceled Memorial Day ceremonies scheduled for Monday and closed some local parks as the storm drew closer. \"I am encouraging all area residents to stay indoors and off the streets as the storm hits,\" said Jacksonville Mayor Alvin Brown. Computer forecast models show Beryl moving on an eventual path back out over the Atlantic after coming ashore, posing no threat to U.S. oil and gas installations in the Gulf of Mexico. The storm is forecast to dump as much as 4 to 8 inches (10-20 cm) of rain, with as much as 12 inches (30 cm) in some areas, and threatens rip currents and possible coastal flooding, the hurricane center said. Beryl formed off the South Carolina coast late on Friday as a subtropical storm, a reference to the storm\'s structure. Subtropical storms usually have a broader wind field than tropical storms and shower and thunderstorm activity farther removed from the storm\'s center. It was reclassified as a tropical storm on Sunday. Beryl followed the season\'s first major storm, Tropical Storm Alberto, which was the earliest-forming Atlantic storm since 2003. The Atlantic hurricane season officially runs from June 1 to Nov. 30, though it is not unusual for storms to form earlier.