NEW YORK — The year's first tropical storm warning in the United States was issued on Friday by the National Weather Service for the coast of South Carolina, five days before the official start of the Atlantic hurricane season. The bulletin by the National Hurricane Center in Miami warned of tropical storm conditions reaching South Carolina's coastline within 36 hours — in the midst of the Memorial Day holiday weekend — from the Savannah River north to the Little River Inlet. Tropical storms are defined as a cyclonic weather systems packing winds with sustained surface speeds ranging from 39 to 73 mph (63 to 119 kph). The current threat to South Carolina was posed by the formation of a tropical depression off the southeastern United States, marking the second such weather system of 2016, following one that grew into Hurricane Alex in the far eastern Atlantic in January, according to the Hurricane Center. Alex, a rare wintertime storm that threatened the Azores island group far off the coast of Portugal, never came near the United States. The latest weather system, now designated Tropical Depression Two with maximum sustained winds of 35 mph (55 kph), was expected to decrease in forward speed on Saturday and Sunday as it nears the coast, the Hurricane Center said. At that point, it would be named Bonnie, and by next Wednesday would rank as the first of the 2016 Atlantic hurricane season, which officially runs from June 1 to through Nov. 30. Tropical storm conditions were expected to reach coastal South Carolina by Saturday night, according to forecasters. The depression's center on Saturday morning was located near latitude 29.9 North, longitude 77.0 West, the Hurricane Center said. The weather system was expected to produce 1 to 3 inches (3 to 8 cm) of rainfall from the upper coast of Georgia through eastern South Carolina and into southeastern North Carolina. Tidal storm surge flooding of 1 to 2 feet (30 to 60 cm) above ground level also was expected in the storm warning area, the Hurricane Center said. US meteorologists have predicted an increase in the number of named storms this hurricane season compared with below-average numbers during the past three years. The National Oceanic and Atmospheric Administration forecast a 70 percent likelihood of 10 to 16 named storms in the upcoming hurricane season. By comparison, 2015 saw 11 named storms, including four hurricanes, of which two were major, according to federal data.
