11 p.m. update

The National Hurricane Center's 11 p.m. update on Tropical Storm Colin extends the tropical storm watch area from Altamaha Sound north to the mouth of the South Santee River in South Carolina, meaning coastal Bryan is under the watch.

Meanwhile, the tropical storm watch that had been from Altamaha Sound south to the Flagler/Volusia county line in Florida is now a tropical storm warning. 

The cone of uncertainty has shifted slightly to the south, but all of coastal Georgia is still included.

In a related development, the National Weather Service has issued a flash flood watch effective from Monday afternoon to Tuesday morning for many coastal Georgia and South Carolina counties, including Bryan.

Original 8 p.m. post

Tropical Storm Colin has formed in the Gulf of Mexico, and all of coastal Georgia is within its cone of uncertainty, according to the National Hurricane Center.

At 8 p.m. EDT Sunday, the center of Colin was about 460 miles southwest of Tampa, Florida with maximum sustained winds of 40 mph. It is moving to the north at 9 p.m., according to the center.

The closest tropical storm watch stretches from Altamaha Sound to the Flagler/Volusia county line in Florida.

The local National Weather Service forecast says that tropical storm conditions are possible Monday night, potentially bringing 1-2 inches of rain.

The storm is expected to move quickly, which should limit rainfall totals. Any changes in the track could increase or decrease potential precipitation amounts.

It is not forecast to reach hurricane strength, according to the Hurricane Center.