Caribbean Sea: Tropical Storm Ida tracking northwest over the central Caribbean Sea Aug. 27 /update 1

Event

Tropical Storm Ida is tracking northwestward over the central Caribbean Sea, southwest of Jamaica. As of 05:00 EDT Aug. 27, the system's center of circulation was approximately 80 km (50 miles) north-northwest of Grand Cayman, Cayman Islands.

Forecast models indicate the system will strengthen as it continues to track in a northwesterly direction and make landfall as a tropical storm over Isla de la Juventud and western Cuba the afternoon of Aug. 27. The system is likely to gain additional strength and become a category three hurricane as it tracks over the Gulf of Mexico and approaches the US Gulf Coast through the afternoon of Aug. 29. Ida is forecast to make landfall as a Category 3 hurricane west of Port Fourchon, Louisiana evening Aug. 29. After landfall, the storm is likely to weaken rapidly into a tropical storm as it turns to track north, transiting southern Louisiana and western Mississippi through early Aug. 31. The system is forecast to turn to track northeast across northern Mississippi and dissipate near the Alabama-Tennessee border by Sep. 1. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

Authorities have issued a state of emergency for Louisiana in advance of the storm. A voluntary evacuation for Grand Isle, Louisiana was issued 18:00 Aug. 26 and a mandatory evacuation is likely to be issued after 10:30 Aug. 27. Four hurricane shelters have been opened on Grand Cayman, Cayman Islands, and are located at Sir John A. Cumber Primary School in West Bay, the Red Cross building on Huldah Avenue, Clifton Hunter High School in Frank Sound, and the Elliott Connolly Civic Centre in Gun Bay, East End. The shelters on Cayman Brac and Little Cayman, Cayman Islands are located at Aston Rutty Centre and the Public Works Department Building respectively.

Government Advisories
As of 05:00 EDT Aug. 27, authorities have issued advisories for the following areas:

• Storm Surge Watch: Sabine Pass to Alabama-Florida border; Vermilion Bay; Lake Borgne; Lake Pontchartrain; Lake Maurepas; Mobile Bay

• Hurricane Watch: Cameron, Louisiana to the Mississippi-Alabama border; Lake Pontchartrain; Lake Maurepas; metropolitan New Orleans

• Tropical Storm Warning: Cayman Islands; the Cuban provinces of Matanzas, Mayabeque, Havana, Artemisa, Pinar del Rio, and the Isle of Youth.

• Tropical Storm Watch: Mississippi-Alabama border to the Alabama-Florida border

Officials are likely to modify or issue additional warnings and/or watches in response to the developing system in the coming hours and days.

Hazardous Conditions
Tropical Storm Ida will likely bring heavy rainfall, strong winds, and rough seas to coastal areas through at least Aug. 30. Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, rivers, and urban areas with easily overwhelmed stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Flooding could isolate some communities for several days. Forecasts indicate the system may produce 15-25 cm (6-10 inches) of rainfall across Jamaica; 20-30 cm (8-12 inches) of rainfall in the Cayman Islands, Isla de la Juventud, and western Cuba.

Prolonged sea swells and storm surge generated by the system will likely result in coastal flooding if the system approaches land. Persistent onshore flow could make it difficult for surge to recede and for water levels to decrease in coastal river catchments. In addition to the heavy rain, flooding, and storm surge, the storm could produce damaging wind gusts, resulting in power outages due to uprooted trees and toppled utility lines. Water levels are likely to rise between 0.6-1.2 meters (2-4 feet) along the coast of Isla de la Juventud and western Cuba.

Transport
Inclement weather associated with the storm could trigger localized business, transport, and utility disruptions through at least Aug. 30 in coastal areas of Jamaica, Cayman Islands, Cuba, Yucatan Peninsula, and the US Gulf Coast. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Areal flooding in urban locations could also result in severe traffic congestion, while strong winds will pose a hazard to high-profile vehicles. Heavy rain and low visibility may trigger flight disruptions at regional airports.

Disruptions triggered by inclement weather and resultant hazards, such as flooding could persist well after conditions have improved. If there is severe damage to infrastructure, repair or reconstruction efforts may exacerbate residual disruptions.

Advice

Activate contingency plans in areas where officials forecast hurricane or tropical storm conditions. Heed all evacuation orders. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the high 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 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 days. Keep any necessary medications in a waterproof container.

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
National Weather Service