Hurricane Sam, which at 5:00 a.m. Sunday was a dangerous category 4 storm, will pass well north of the Leeward Islands, including the U.S. Virgin Islands, as the Caribbean dodges yet another storm during the active 2021 hurricane season.
According to the National Hurricane Center's 5:00 a.m. forecast, Sam was moving toward the west-northwest near 8 mph. "This general motion is expected to continue today, followed by a turn toward the northwest on Monday. Then, a northwestward motion is forecast to continue through midweek," N.H.C. said.
The hurricane gained strength rapidly and on Sunday morning was sustaining winds of 145 mph with higher gusts. "Some fluctuations in intensity are expected during the next day or so. Thereafter, some slow weakening is forecast. Sam is a small hurricane. Hurricane-force winds extend outward up to 30 miles (45 km) from the center and tropical-storm-force winds extend outward up to 90 miles," said N.H.C.
Sam is forecast to be a category 3 hurricane when it passes 400 miles northeast of St. Thomas, which will be the storm's closest approach to the U.S. Virgin Islands.
However, while the Caribbean islands will be spared the impact of another dangerous storm, new systems are already posing a threat, with the National Hurricane Center pointing to one system that is expected to become a tropical depression midweek, and another already in the Atlantic with some favorable conditions for development.
System coming off coast of Africa
N.H.C. at 5:00 a.m. said a tropical wave is expected to move off the west coast of Africa on Monday. Environmental conditions are forecast to be conducive for gradual development thereafter, and a tropical depression could form by midweek while the system moves westward to west-northwestward at 10 to 15 mph over the far eastern tropical Atlantic.
N.H.C. gave the system a 60 percent development chance in the next five days, and near zero in the next 48 hours.
System already in the Atlantic
A broad area of low pressure could form over the eastern or central tropical Atlantic early this week, to the west of the tropical wave that will be moving off the coast of Africa, said the N.H.C. "Thereafter, environmental conditions could support some development of this disturbance while it moves westward at 5 to 10 mph through the middle of the week."
Development chance in the next 48 hours stood at near zero and 30 percent in the five-day window.
Correction: Sept. 26, 2021 at 5:55 a.m.
Because of a text error, a previous version of this story stated that Hurricane Sam was a category 5 storm at 5:00 a.m. Sunday, Sept. 26. That's incorrect. Sam was a dangerous Cat. 4 storm at 5:00 a.m. Sunday, according to the National Hurricane Center. The story has been updated to reflect the correct information.