Tropical Depression Bonnie is back. (NOAA)

Like a zombie rising from the crypt, Tropical Depression Bonnie is back. In truth, it never left, although earlier this week it weakened beyond the point of recognition. And to make things even more interesting, the next storm — which would be named Colin — could form in the Gulf of Mexico over the next week. If that happened, it would be the earliest third tropical storm of the season on record.

Bonnie originally formed on Friday, made landfall in South Carolina on Sunday, and then transitioned into a non-tropical cyclone on Monday. Since then, it has regained tropical characteristics, and the National Hurricane Center has begun to issue advisories on the system. It’s not a tropical storm anymore; it’s a weaker system called a tropical depression. Nonetheless, since this low pressure system was once “Bonnie,” it gets that name again.


Radar loop of Tropical Depression Bonnie on Thursday morning. (National Weather Service/Brian McNoldy)

In the past few days, the disturbance meandered back over the water just off the North Carolina coast and is now centered near Cape Hatteras. With help from the warm Gulf Stream and low vertical wind shear, it could even regain tropical storm intensity as it heads eastward out to sea.


Forecast track for Tropical Depression Bonnie. (National Hurricane Center)

Over in the Gulf of Mexico, forecast models have been consistently indicating that a tropical cyclone could form. Although the low pressure system does not exist yet, we look for the models to agree, and we look for consistency in their forecasts over time when deciding to trust them. This fits that description.

The National Hurricane Center is giving this a 30 percent chance of formation in the Gulf of Mexico or western Caribbean within the next five days.

At this time, even if it does form, it does not look like it would be anything worse than a tropical storm — but we will keep a very close eye on it. The entire Florida peninsula should be especially vigilant for possible impacts early next week (mostly rain).

These images below show the latest surface wind forecasts from four global models valid on Monday-Tuesday of next week.


Snapshots of forecasts from four global models: GFS (upper left), ECMWF (upper right), CMC (lower left), and NAVGEM (lower right). These are latest runs from Thursday morning and are valid next Monday-Tuesday. (tropicaltidbits.com)

Looking back at tropical storm history, we find that this storm, if it forms, would be the earliest third tropical storm on record.

Earliest: June 12 (1887)

2nd Place: June 18 (1959 and 2012)

3rd Place: June 23 (1968)

Latest: Trick question… 1914 never even reached 3!

Median: Aug. 24