Subtropical Storm Andrea expected to dissipate by Wednesday

The National Hurricane Center on Monday evening announced the formation of Subtropical Storm Andrea, 12 days before the official start of hurricane season.

The center said a patch of stormy weather north of the Bahamas has developed a well-defined center and sustained winds of 40 miles per hour, according to data from an Air Force Reserve reconnaissance plane. The storm may strengthen to 45 mph early Tuesday.

But Andrea is expected to dissipate by Wednesday as it’s absorbed into a cold front, the center said. And before that, the storm is expected to head north, where it may affect Bermuda but will pose no threat to the United States.

Tropical cyclones are classified by their wind speed from tropical depression to tropical storm to hurricane. A subtropical storm is one with a windspeed of at least 39 mph. A subtropical storm tends to be drier and less intense than a tropical storm. It lacks the potential to strengthen into a hurricane unless it moves over warmer waters and becomes a tropical storm.

Though the official start of hurricane season is about two weeks away, it’s not unusual to have a system being watched by the hurricane center before that time.

Hurricane season begins June 1 and runs through Nov. 30, with the peak period for storms coming in August and September. Early forecasts call for an average to slightly below average season.