System East of North Carolina Becomes Tropical Storm Bill
Monday 11 pm Update: The tropical depression east of North Carolina strengthened into Tropical Storm Bill. Maximum sustained winds were estimated to be at 45 mph and the storm was moving northeast at 23 mph. The forecast track of Tropical Storm Bill remains largely unchanged, and the season's second tropical storm is not a threat to South Carolina.
The season's second tropical depression has formed a little more than 100 miles from Cape Hatteras, North Carolina late Monday morning. It is expected to strengthen into a tropical storm later Monday.
The depression formed along a decaying cold front near the Southeastern U.S. coastline. One of the most common ways that tropical systems form in June is when a mid-latitude low pressure area (often referred to as a "cold core" low in meteorology) or front moves over warmer ocean water. Over a couple of days, the low pressure area acquires warm core, or tropical, characteristics.
The steering winds between a trough in the eastern United States and a subtropical ridge over the Bahamas will force the system to move toward the northeast and away from the United States. There is enough warm water for strengthening as it moves over the Gulf Stream, but it is expected to transition back to a non-tropical low on Wednesday as it moves over the colder waters of the North Atlantic.