Caribbean Sea: Tropical Storm Ian is tracking westward late Sept. 24 /update 2

Event

Tropical Storm Ian is tracking westward in the central Caribbean Sea late Sept. 24. As of 23:00 EDT, the storm's center of circulation was approximately 630 km (395 miles) southeast of Grand Cayman, Cayman Islands.

Forecast models indicate the system will strengthen further as it gradually turns to track northwestward, passing well west of Jamaica late Sept. 25. Ian is forecast to become a category 2 hurricane before making a close approach to the Cayman Islands early Sept. 26, passing west of Grand Cayman. The system is forecast to strengthen further into a Category 4 hurricane before making landfall over far western Cuba early Sept. 27. The storm is then forecast to turn northward as it crosses western Cuba and the Gulf of Mexico through late Sept. 28 before weakening into a category 1 hurricane and making landfall over western Florida Peninsula late Sept. 29. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

As of late Sept. 24, authorities have issued the following watches and warnings:

• Hurricane Warning: Grand Cayman

• Hurricane Watch: Cuban provinces of Isla de Juventud, Pinar del Rio, and Artemisa

• Tropical Storm Watch: Little Cayman and Cayman Brac as well as the Cuban provinces of La Habana, Mayabeque, and Matanzas

Officials could issue new warnings and/or watches in response to the developing system in the coming hours.

Forecast models predict rainfall accumulations of 10-20 cm (4-8 inches) over western Cuba, 7.5-15 cm (3-6 inches) over Jamaica and the Cayman Islands, and 5-10 cm (2-4 inches) over the Florida Keys and southern Florida. The heavy rainfall could produce flood impacts in the affected areas, including flash and urban flooding, as well as landslides over higher terrain, especially in Jamaica and Cuba. Flash and urban flooding is possible across the Florida Keys and Florida peninsula through Sept. 28 while flooding and river level rises are possible across northern and central Florida and parts of the Southeast through Sept. 30 due to the already saturated antecedent conditions.

Storm surge could raise water levels by 0.6-1.2 meters (2-4 feet) above normal tide levels along the coast in the Cayman Islands late Sept. 25-26 and by 2.8-4.3 meters (9-14 feet) above normal tide levels along the coast of western Cuba late Sept. 26-27. Swells generated by the storm system will begin to affect Jamaica and the Cayman Islands Sept. 25 and spread northwestward to southwestern coast of Cuba and the coasts of Honduras, Belize, and the Yucatan Peninsula of Mexico by Sept. 26.

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

The inclement weather could trigger localized business, transport, and utility disruptions, rendering some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Raw sewage and other hazardous materials mixed with floodwaters pose a serious health threat.

Advice

Activate contingency plans in areas where officials forecast typhoon or 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
Jamaica Meteorological Service
Cuban Meteorological Institute
US National Weather Service