Tropical Storm Ernesto has been bringing heavy rainfall to the northeastern Caribbean islands and is gaining strength as it approaches. Officials in Puerto Rico and the Virgin Islands are preparing for its arrival and the potential for hurricane-level conditions.

Ernesto formed into a tropical storm on Monday night and quickly made its way toward the northern Leeward Islands. Early Tuesday, it moved overhead, passing close to Guadeloupe and Montserrat. According to the National Hurricane Center, as of 11 a.m., Ernesto was about 155 miles southeast of St. Croix and 250 miles southeast of San Juan, Puerto Rico.

The storm has been strengthening, with wind speeds reaching 50 mph as it moved toward the Virgin Islands and Puerto Rico at 18 mph. Meteorologists predict that Ernesto could release as much as six inches of rain in parts of the islands before it continues into the warm waters of the western Atlantic later this week.

On Monday night, Puerto Rico’s Governor Pedro Pierluisi announced the cancellation of the first day of public school classes, mobilization of the National Guard, and the opening of numerous shelters across the island. He advised both residents and visitors that, although the storm may not reach hurricane status until after passing Puerto Rico, it is still expected to deliver heavy rainfall, with totals in some areas potentially hitting 10 inches.

The U.S. Virgin Islands government also declared the closure of all schools on Tuesday. Governor Albert Bryan Jr. emphasized the importance of taking the storm seriously during a news briefing.

Experts observe signs of inner core development in Ernesto

Forecasters detected signs of an inner core forming as Ernesto entered the warm Caribbean Sea on Tuesday. This led the National Hurricane Center to caution that “Ernesto could reach hurricane strength in about 24 hours as it moves north of Puerto Rico.”

Due to Ernesto’s intensification, hurricane watches have been issued for the U.S. and British Virgin Islands, along with Culebra and Vieques. National Hurricane Center Deputy Director Jamie Rhome urged those in affected areas to prepare for possible hurricane conditions during a livestream.

Additionally, tropical storm warnings remain in effect, alerting residents about “significant flooding” and the risk of mudslides across the region, including Puerto Rico, the U.S. and British Virgin Islands, St. Kitts, Nevis, Montserrat, Antigua, Barbuda, Guadeloupe, St. Martin, St. Barthelemy, Vieques, and Culebra, as reported by the National Hurricane Center.

What is the projected path of Tropical Storm Ernesto?

Ernesto is forecasted to travel over or near the Virgin Islands and Puerto Rico starting Tuesday evening and continuing into Wednesday.

“Heavy rainfall can lead to significant flash flooding and mudslides in parts of the Leeward Islands today, and over the Virgin Islands and Puerto Rico from later today into Wednesday,” warned the National Hurricane Center.

In the latter part of the week, Ernesto is expected to shift northward towards Bermuda, with warm Atlantic waters likely intensifying the storm as it approaches the northern reach of the Greater Antilles. The National Hurricane Center predicts Ernesto may evolve into a major hurricane with wind speeds reaching 111 mph by Friday.

Will Tropical Storm Ernesto affect the U.S. mainland?

While the storm’s heavy rains and winds are expected to largely bypass the U.S. mainland, officials have cautioned about hazardous rip currents and turbulent surf along the Atlantic coast. Last year, wave-related incidents led to all fatalities connected to Hurricane Idalia.

On Monday, the Coast Guard advised recreational boaters, fishermen, beachgoers, and water sports enthusiasts in the U.S. Virgin Islands and Puerto Rico to avoid going into the ocean “due to worsening sea conditions and dangerous rip currents linked to Tropical Storm Ernesto.”

“We encourage the public and the maritime community to prioritize safety and not underestimate the storm’s impact,” stated Capt. Luis Rodriguez, commander of Coast Guard sector San Juan.

What makes it unlikely for Ernesto to impact the U.S. mainland?

Forecasts indicate that Ernesto is unlikely to impact the U.S. mainland directly and is expected to veer out to sea. This pattern is typical — annually, only about three tropical storms or hurricanes forming in the Atlantic actually reach U.S. shores, as indicated by the textbook Meteorology Today.

Hurricanes are influenced by large weather systems and global wind patterns. Typically, storms are pushed northward around or along the western side of a high-pressure ridge in the Atlantic, often referred to as the Bermuda High. If the high pressure is positioned to the east, hurricanes usually navigate around its western edge and head into open waters without making landfall, according to the University of Rhode Island. This scenario is anticipated for Ernesto later this week, according to the National Hurricane Center.

In some instances, the high-pressure system is positioned to the west and stretches significantly to the south. This situation can hinder storms from shifting northward, forcing them to travel westward and inadvertently placing Florida, Cuba, and the Gulf of Mexico directly in their path.

Tropical Storm Ernesto develops amid a busy hurricane season

Should Ernesto gain strength and become a Category 1 hurricane, it will mark the third hurricane of this season. Experts anticipate this hurricane season to be above normal due to exceptionally warm ocean temperatures.

Residents and officials throughout the eastern United States were still dealing with the aftermath of Hurricane Debby, a powerful storm responsible for severe flooding from Florida to western New York and Pennsylvania. Last month, Hurricane Beryl made history as the earliest Category 5 hurricane recorded in the Atlantic, and was associated with more than 20 fatalities across Texas and the Caribbean.