Tropical Storm “Tammy” approaching the Leeward Islands, expected to strengthen into a hurricane

Tropical Storm “Tammy” is expected to strengthen into a hurricane by October 21, 2023, as it moves towards the Leeward Islands. Heavy rains, wind, and potential flooding are expected to begin today, affecting several Caribbean islands.

• Tammy is expected to strengthen to a hurricane by Saturday while it moves near or over portions of the Leeward Islands. Tropical storm conditions are expected to begin in portions of the Lesser Antilles within the tropical storm warning area this afternoon or evening, with hurricane conditions possible within the hurricane watch area on Saturday. Additional watches and warnings could be required later today.
• Heavy rains from Tammy will begin to affect the Leeward and northern Windward Islands today, spreading into the British and U.S. Virgin Islands and Puerto Rico over the weekend. This rainfall may produce isolated flash and urban flooding, along with isolated mudslides in areas of higher terrain.

At 12:00 UTC on October 20, 2023, Tropical Storm “Tammy” was located 150 km (93 miles) northeast of Barbados and 290 km (180 miles) east-southeast of Martinique. The storm’s maximum sustained winds were 100 km/h (62 mph), with a minimum central pressure of 1 000 hPa. The storm was moving west-northwest at 11 km/h (7 mph).

On the forecast track, the center of Tammy will move near or over portions of the Leeward Islands tonight and on Saturday, and then move north of the northern Leeward Islands on Sunday.

A Hurricane Watch is currently in effect for Guadeloupe, Antigua and Barbuda, Montserrat, St. Kitts and Nevis, Anguilla, St. Maarten, St. Martin, and St. Barthelemy. The watch indicates that hurricane conditions are possible within the next 24 to 48 hours.

A Tropical Storm Warning has been issued for Dominica, Guadeloupe, Antigua and Barbuda, Montserrat, St. Kitts and Nevis, Anguilla, St. Maarten, St. Martin, St. Barthelemy, Saba, and St. Eustatius. This warning signifies that tropical storm conditions are expected within 36 hours.

Tropical Storm Watches have been issued for Barbados and Martinique, suggesting that storm conditions are possible within 48 hours.

Tammy’s heavy rains are anticipated to begin affecting the Leeward Islands and northern Windward Islands today. The rainfall could result in isolated flash and urban flooding, as well as mudslides in higher terrain areas. Specifically, the Leeward Islands are expected to receive 100 to 200 mm (4 to 8 inches) of rain, with maximum amounts up to 300 mm (12 inches). The Northern Windward Islands could see 50 to 100 mm (2 to 4 inches), with a maximum of 150 mm (6 inches).

Storm surge could raise water levels by as much as 0.3 to 0.9 m (1 to 3 feet) above normal tide levels in areas close to where Tammy’s center moves across the Leeward Islands. Additionally, swells generated by Tammy will continue to affect portions of the Lesser Antilles, posing life-threatening surf and rip current conditions.

References:

¹ Tropical Storm Tammy – Intermediate Advisory Number 8A – NWS National Hurricane Center Miami FL AL202023 – 800 AM AST Fri Oct 20 2023