Tropical system may brew near Bahamas this weekend; Will US East Coast be at risk for impact?

By Alex Sosnowski, AccuWeather senior meteorologist

August 9,2017, 2:57:51PM,EDT

 

A batch of thunderstorms of interest over the central Atlantic, dubbed 99L, has the potential to develop and approach the Atlantic coast of the United States next week.

When clusters of thunderstorms in the Atlantic Ocean have a chance to become a tropical depression or storm, they are assigned a number between 90 and 99. The "L" designation refers to a system under investigation in the Atlantic.
How much development occurs and how close to the coast 99L will track is uncertain at this time, according to AccuWeather Hurricane Expert Dan Kottlowski.

Coastal, cruise and shipping interests in the western Atlantic should monitor the progress of this system.
"Dry air and strong winds aloft are inhibiting the development of 99L at this time," Kottlowski said.
Nintey-nine L will be guided around the clockwise flow of a large area of high pressure over the middle of the Atlantic Ocean.
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"We expect 99L to move northwestward and into a zone more favorable for tropical development just northeast of the Bahamas this weekend," Kottlowski said.
In this area, 99L could organize into a tropical depression and possibly Tropical Storm Gert.
Depending on the shape of the high pressure area to the east and the speed of a non-tropical storm approaching from the west, a more northward turn is likely, Kottlowski stated.
How quickly this occurs would determine how close to the coast of the U.S. the system tracks.
The system could remain a few hundred miles offshore or could reach the Carolina coast.
"At this time, the more likely scenario is for the tropical system to stay offshore," Kottlowski said.
However, if the system strengthens to a tropical storm or hurricane, then seas and surf would build from the Bahamas this weekend to the Atlantic coast of the U.S. and Bermuda early next week.
The non-tropical storm could stall and result in torrential rain and increase the risk of flooding in part of the eastern quarter of the nation during the first part of next week. This can occur even if the two systems remain separated.

Portions of the Southern states will be inundated with downpours prior to the tropical system's approach and its departure.
The tropical system could delay the arrival of another wave of cool, dry air in the coastal Northeast until the middle of next week.