The first tropical storm of the 2012 Atlantic hurricane seasonformed Saturday off the southeastern US coast with winds of 45 miles (75 kilometers) per hour, US weather forecasters said. Dubbed “Alberto,” the storm was 140 miles (225 kilometers) southeast of Charleston, South Carolina, moving southwest at a speed of three miles (six kilometers) per hour, the National Hurricane Center. It posed no immediate threat to land but a tropical storm watch may be needed for parts of the Carolina coasts Saturday [...]