Maps show Tropical Storm Ernesto’s path and forecast as it passes north of Puerto Rico

Tropical Storm Ernesto is expected to become a hurricane Wednesday morning as it moves north of Puerto Rico, the National Hurricane Center said, adding that it could become a major hurricane “in a couple of days.”

Ernesto became the fifth named storm of the 2024 Atlantic hurricane season when it formed Monday along a fast-moving path to the Caribbean. The storm comes on the heels of Hurricane Debby, which lashed parts of the southeastern United States last week with disastrous flooding and brewed up a flash of severe weather that ultimately touched much of the East Coast. Ernesto isn’t expected to strike the U.S. mainland, the hurricane center said.

As of 5 a.m. EDT, forecasters said Ernesto had maximum sustained winds of 70 mph, just shy of the 74 mph needed for it to be classified as a hurricane, and was moving northwest at 16 mph. It was centered about 85 miles north-northwest of San Juan, Puerto Rico, the hurricane center said.

A hurricane watch was in effect for the British Virgin Islands. A tropical storm warning was posted for the U.S. and British Virgin Islands, Puerto Rico, Vieques and Culebra.  

Hurricane watches are issued when hurricane conditions are possible in a given area within 12 hours or so. Tropical storm warnings are issued when forecasters expect tropical storm conditions to impact an area within 36 hours. Powerful winds and other weather conditions typical of a tropical storm were already happening in the Leeward Islands, they said.

Tropical-storm-force winds extended outward up to 150 miles from Ernesto’s center Wednesday morning — a sizable expansion from its 70-mile reach Tuesday morning, according to the hurricane center. 

Not unlike Debby, which dumped devastating and, in some instances, historic rainfall on southeastern U.S. states last week, Ernesto’s primary threat was heavy rain, although less rain was forecast for this week compared with last week’s hurricane.

The hurricane center said the storm is expected to produce between 4 and 6 inches of rain over the U.S. and British Virgin Islands and up to 10 inches across southeastern Puerto Rico. There was “torrential rain” falling on eastern Puerto Rico Wednesday morning.

“Minor coastal flooding remains possible in areas of onshore winds along the eastern coast of Puerto Rico, including the islands of Culebra and Vieques, and in the U.S. Virgin Islands, including St. Thomas, St. John, and St. Croix,” the center added.