North Atlantic Ocean: Hurricane Tammy tracking north-northwestward in the North Atlantic Ocean just north-northwest of Barbuda as of late Oct. 21 /update 4

Event

Hurricane Tammy is tracking north-northwestward in the North Atlantic Ocean just north-northwest of Barbuda, Antigua and Barbuda, late Oct. 21. As of 23:00 AST, the system's center of circulation was approximately north-northwest of Barbuda.

Forecast models indicate that the storm will maintain Category 1 hurricane strength as it continues north-northwestward and passes east of Anguilla early Oct. 22, before tracking north-northwestward, then northward and north-northeastward away from the Leeward Islands and into the Sargasso Sea through Oct. 26. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.

As of late Oct. 21, authorities have issued the following watches and warnings:

• Hurricane warning: Barbuda, Anguilla, St. Maarten, St. Martin, and St. Barthelemy

• Tropical storm warning: Saba and St. Eustatius

Hurricane conditions are likely over portions of the northern Leeward Islands, and tropical storm conditions are forecast within the tropical storm warning areas through late Oct. 21. Tropical storm conditions are possible in the British Virgin Islands through Oct. 22. Authorities will likely issue new warnings throughout the system's progression in the coming days. Rainfall totals of 10-20 cm (4-8 inches) are likely across the Leeward Islands, an additional 5-10 cm (2-4 inches) across Dominica and Martinique, and 2.5-5 cm (1-2 inches) across the British Virgin Islands, US Virgin Islands, and 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. Large and dangerous waves near the coast will accompany the storm surge. Swells generated by Tammy are forecast to affect portions of the Lesser Antilles over the coming days, likely producing life-threatening surf and rip current conditions.

Authorities in Antigua and Barbuda have advised residents in flood-prone and low-lying areas to move to higher ground. Leeward Islands Air Transport (LI) canceled some flights across the Leeward Islands Oct. 20-21, and interCaribbean Airways (JY) canceled flights on all routes Oct. 21, including between Dominican and Barbados and Antigua and Barbados. Pointe-a-Pitre International Airport (PTP) in Guadeloupe is scheduled to reopen Oct. 22, while V.C. Bird International Airport (ANU) in Antigua is scheduled to reopen the afternoon of Oct. 22. Authorities closed all schools across Antigua and Barbuda, Dominica, and Guadeloupe 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