Atlantic: Tropical Storm Ernesto tracking westward toward the Leeward Islands as of late Aug. 12 /update 2

Tropical Storm Ernesto is tracking westward in the North Atlantic Ocean late Aug. 12. As of 23:00 AST, the system's center of circulation was approximately 265 km (165 miles) east-southeast of Antigua, Antigua and Barbuda.

Forecast models indicate that the storm will strengthen and make landfall over Guadeloupe early Aug. 13. The system is forecast to strengthen further as it tracks west-northwestward and then northwestward in the Caribbean Sea and makes another landfall over Saint Croix Island, US Virgin Islands, late Aug. 13 before making landfall over Culebra Island, Puerto Rico, early Aug. 14. The storm is then expected to strengthen into a Category 1 hurricane as it tracks north-northwestward and then northward away from the Greater Antilles Aug. 14-15. The storm is likely to strengthen further into a Category 2 hurricane as it tracks northward, then north-northeastward across the Sargasso Sea region of the North Atlantic Ocean and passes east of Bermuda late Aug. 17. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.

As of late Aug. 12, authorities have issued the following watches and warnings:

Tropical Storm Warnings

• Guadeloupe

• St. Kitts, Nevis, Montserrat, Antigua, Barbuda, and Anguilla

• St. Martin and St. Barthelemy

• Sint Maarten

• British Virgin Islands

• US Virgin Islands

• Puerto Rico

• Vieques

• Culebra

Authorities will likely issue new warnings throughout the system's progression in the coming days. Tropical storm conditions are expected within the warning area for the Leeward Islands from early Aug. 13 and spread over the Virgin Islands and Puerto Rico by the evening of Aug. 13.

The system is forecast to produce total rainfall accumulations of 10-15 cm (4-6 inches) over parts of the Leeward Islands and Virgin Islands and 7.5-15 cm (3-6 inches) over Puerto Rico, with maximum amounts of 25 cm (10 inches). Rainfall totals of 5-10 cm (2-4 inches) are also possible over eastern Hispaniola and 2.5-10 cm (1-4 inches) across the Windward Islands through early Aug. 16.

Storm surge may raise water levels by as much as 0.3-0.9 meters (1-3 feet) above ground level along the eastern coast of Puerto Rico from San Juan to Guayama, including the islands of Culebra and Vieques, and in the British Virgin Islands and US Virgin Islands, including St. Thomas, St. John, and St. Croix. Swells generated by the system are forecast to affect portions of the Leeward Islands from late Aug. 12; these are likely to produce life-threatening surf and rip current conditions.

The V.C. Bird International Airport (ANU) in Antigua is closed and scheduled to reopen the afternoon of Aug. 13, while the Princess Juliana International Airport (SXM) in St. Maarten will close early Aug. 13-early Aug. 14. Saba has closed the Juancho E. Yrausquin Airport (SAB) through at least Aug. 13 and canceled all ferry services Aug. 13-15. Motorists are advised to avoid traveling to Fort Bay Aug. 13 due to the risk of flash flooding and landslides. Authorities in Puerto Rico have warned that power outages are likely due to the fragile state of the power grid. Puerto Rico has canceled public school classes, while all schools in Sint Maarten are closed until further notice. Government offices in Saba and St Kitts and Nevis are closed Aug. 13.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. If weather conditions prove hazardous, localized evacuations, flash flooding, and landslides are possible.

The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Stagnant pools of water during and after flooding may increase the incidence of insect- and waterborne diseases, such as dengue fever, cholera, and malaria. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.