Bonnie threatens to form in time to drench US East Coast over Memorial Day weekend

By Alex Sosnowski, AccuWeather.com Senior Meteorologist
May 28, 2016; 8:29 AM ET

Tropical Depression Two intensified northeast of the Bahamas on Friday afternoon and will approach the southeastern coast of the United States with downpours, building surf and an increasing breeze during Memorial Day weekend.

The system can become a tropical storm at any time this weekend, with the potential to become the second named storm of the season: Bonnie.

Alex was the first official tropical storm and hurricane of 2016.

According to AccuWeather Hurricane Expert Dan Kottlowski, as the system moves away from strong winds aloft and toward warmer waters of the Gulf Stream, it should strengthen and organize.

Regardless of a tropical depression or tropical storm and the movement thereof, the approach will have an impact on coastal areas, especially from Georgia to southeastern Virginia through the holiday weekend and perhaps into next week.

The biggest threats will be to bathers and boaters in the region.

"How rough conditions get will depend on how strong the system becomes, how close to the coast it gets and whether or not the system stalls," Kottlowski said.

The depression is likely to take a swift northwestward track into Sunday.

As the weekend progresses, a breeze will increase and waves will build. Increasing wave action will cause the number and strength of rip currents to increase.

While Saturday will start with favorable outdoor conditions, enough rain will fall within a few dozen miles of the southeastern U.S. coast to spoil outdoor activities late Saturday afternoon, Sunday and Memorial Day.

"Moderate to heavy rainfall is likely, especially over eastern South Carolina and eastern North Carolina from Saturday night into early next week," Kottlowski said.

There is a chance the rain becomes heavy enough to cause localized flooding.

Whether or not frequent downpours spread well inland over the Carolinas or spread northward along the mid-Atlantic coast will depend on the track of the storm later this weekend into next week. Should the system turn northward, winds, seas and surf will also build farther to the north along the coast.

A weak system, such as a tropical depression is more prone to track erratically or stall, when compared to a well-organized tropical storm or hurricane.

If the system stalls, an extended period of downpours, rough surf and beach erosion would occur.

A small zone of flooding is possible near and north of the path of the storm. How much flooding occurs will depend on the speed, track and strength of the storm and if the approach occurs around the time of high tide.

All marine and coastal interests should monitor the progress of this developing system through the weekend.

The rest of the tropical Atlantic remains relatively quiet.

"We see no other signs of tropical development in the Atlantic over the next several days," Kottlowski said.

AccuWeather is projecting an above-average number of tropical storms and hurricanes in the Atlantic basin this season.