A disorganized system of storms that forecasters expected to form into Tropical Storm Isaias late Wednesday may be headed for South Carolina.
In its 8 p.m. update, the National Hurricane Center had not yet upgraded the egg-shaped collection of showers to tropical storm status. The system continued to bring heavy rain and gusty winds to the U.S. and British Virgin Islands, and to Puerto Rico.
Forecasters expected the storms to pass south of Puerto Rico Wednesday night, near or over Hispaniola on Thursday, near eastern Cuba and the southeastern Bahamas on Friday, and approach southern Florida Friday night.
But the storm's track is "more uncertain than usual," forecasters warned.
The southern half of South Carolina's coast was inside the Hurricane Center's cone of uncertainty in its long-range forecast, but just barely, with future-Isaias approaching at tropical storm strength on Monday. Expect that prediction to change in the coming days.
The stretched-out, egg-shaped collection of thunderstorms has posed a challenge to forecasters so far. Meteorologists were eagerly waiting to see which side of the system would consolidate into the center of rotation, which will go a long way in determining what track the storm takes.
It's not uncommon for larger tropical waves that roll off the coast of Africa to take their time to start spinning, said meteorologist Jeff Masters, who writes about hurricanes for Yale Climate Communications. The system destined to be Isaias is a large one, with storm-force finds extending over a broad area.
If soon-to-be Isaias does sweep across the Dominican Republic and Haiti as predicted, it could be weakened by mountains on the island, which are known to knock cyclones apart.
Regardless, forecasters urged people across the Caribbean and Florida that impacts will extend beyond the exact track of the storm's center. It's still unclear, however, exactly what threats the storm presents to South Carolina in the long term.
When officially named, Isaias is likely to be the earliest-ever cyclone with a name that starts with "I," a pattern for the 2020 hurricane season so far.