A tropical depression that formed overnight is expected to reach hurricane strength over the next 72 hours, according to the National Hurricane Center.
The depression was officially declared at the 4 a.m. advisory after an Air Force Reserve reconnaissance aircraft found that the system had a well-defined low-level circulation.
The system, which is in the southwest Caribbean Sea and will be named Otto if it forms, will not affect the U.S. But anyone going to Costa Rica for the Thanksgiving holiday may find themselves under a hurricane warning in the next few days.
As of 4 a.m., the depression was about 300 miles east of Bluefields, Nicaragua with maximum sustained winds of 35 mph. It has been meandering in the same general area for the past 12 hours, and little motion is expected today or early Tuesday.
The longer it stays in one place, the more difficult it is for it to form as it will be bringing up cooler water, which can hinder development. But moderate wind shear that is hitting the system now, is expected to weaken in the next three days and Hurricane Otto is forecast to form before landfall.
Forecasters expect it to become a tropical storm later today or tonight.