Tropical Storm Arthur is drenching the southern United States with intense rain that’s expected to cause dangerous flash flooding. The National Hurricane Center in Miami announced the storm’s formation Wednesday. Arthur is the first tropical storm of this year’s Atlantic hurricane season. The forecast says Arthur will move over the northwestern Gulf Coast into Texas, and points eastward to Georgia and the Florida Panhandle. Flooding was the main threat with forecasters warning of life-threatening flash flooding and urban floods through Friday. Rainfall totals were expected to be between 5 and 10 inches, with isolated higher totals near 20 inches.