North Atlantic: Tropical Storm Tammy tracking west-northwestward in the North Atlantic Ocean east of Barbados as of late Oct. 19 /update 1

Event

Tropical Storm Tammy is tracking west-northwestward in the North Atlantic Ocean late Oct. 19. As of 23:00 AST, the system's center of circulation was approximately 270 km (165 miles) east-northeast of Barbados.

Forecast models indicate that the storm will intensify as it tracks generally northwestward, passing north of Barbados Oct. 20, before strengthening further into a category 1 hurricane and making landfall over La Desirade Island, Guadeloupe, early Oct. 21. Tammy is forecast to strengthen slightly as it turns to track north-northwestward and make another landfall over Barbuda Island, Antigua and Barbuda, late Oct. 21. The system will then track north-northwestward then northeastward away from the Leeward Islands through Oct. 24. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.

As of late Oct. 19, authorities have issued the following watches and warnings:

• Hurricane watch: Guadeloupe, Antigua and Barbuda, Montserrat, St. Kitts and Nevis, Anguilla, St. Maarten, St. Martin, and St. Barthelemy

• Tropical storm warning: Dominica, Guadeloupe, Antigua and Barbuda, Montserrat, St. Kitts and Nevis, Anguilla, St. Maarten, St. Martin, and St. Barthelemy

• Tropical storm watch: Barbados, Martinique, Saba, and St. Eustatius

Tropical storm conditions are forecast within the tropical storm warning area from Oct. 20. Hurricane conditions are possible in portions of the Leeward Islands late Oct. 20-21. Authorities will likely issue new warnings throughout the system's progression in the coming days. Rainfall totals of up to 10-20 cm (4-8 inches) are likely across the Leeward Islands, 5-10 cm (2-4 inches) across the northern Windward Islands, and 2.5-5 cm (1-2 inches) over the British and US Virgin Islands into eastern Puerto Rico.

Storm surge could raise water levels by 0.3-0.9 meters (1-3 feet) above normal tide levels near where Tammy tracks across the Leeward Islands. Swells generated by Tammy are forecast to affect portions of the Lesser Antilles over the coming days; these are likely to produce life-threatening surf and rip current conditions.

FlyMontserrat (5M) has canceled all flights the afternoon of Oct. 19-20; the airline has stated that flights are likely to resume the afternoon of Oct. 21. Authorities in Guadeloupe will close Pointe-a-Pitre International Airport (PTP) from 18:00 Oct. 20. All schools across Antigua and Barbuda, Dominica, and Guadeloupe are closed Oct. 20, while all sporting events across Guadeloupe Oct. 20-22 are postponed.

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.

Advice

Activate contingency plans in areas where officials forecast tropical storm conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.

Resources

US National Hurricane Center