North Atlantic: Potential TC 5 tracking westward toward the Leeward Islands as of Aug. 12 /update 1

Potential Tropical Cyclone 5 is tracking westward in the North Atlantic Ocean Aug. 12. As of 11:00 AST, the system's center of circulation was approximately 700 km (435 miles) east-southeast of Antigua, Antigua and Barbuda.

Forecast models indicate that the storm will strengthen into a tropical storm late Aug. 12 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 a close approach to the US Virgin Islands late Aug. 13 before making landfall over eastern 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 approaches Bermuda early Aug. 17. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.

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

Tropical Storm Warnings

• Guadeloupe

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

• Saba and St. Eustatius

• 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 areas from late Aug. 12 or early 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.

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.