Caribbean Sea: Tropical Storm Idalia is largely stationary over the Caribbean Sea late Aug. 27 /update 1

Event

Tropical Storm Idalia is largely stationary over the Caribbean Sea late Aug. 27. As of 23:00 CDT, the system's center of circulation was approximately 235 km (145 miles) south of the western tip of Cuba.

Forecast models indicate that the storm will track north-northeastwards while strengthening into a Category 1 hurricane and make a close approach to far western Cuba the evening of Aug. 28. Idalia is forecast to strengthen further as it continues north-northeastwards across the Gulf of Mexico through Aug. 29 before making landfall over central Florida, US, early Aug. 30. After landfall, the storm is likely to weaken rapidly into a tropical storm as it crosses northeastern Florida and enters the North Atlantic Ocean through the afternoon of Aug. 30. The storm is likely to weaken further as it tracks northeastward along the coasts of Georgia, South Carolina, then North Carolina through Aug. 31 before tracking away from land through Sept. 1. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.

As of late Aug. 27, authorities have issued the following coastal watches and warnings:

• Hurricane Warning: Pinar del Rio, Cuba

• Tropical Storm Warning: Yucatan Peninsula in Mexico from Tulum to Rio Lagartos, including Cozumel, the Isle of Youth in Cuba, and Dry Tortugas, Florida, US

• Tropical Storm Watch: south of Englewood to Chokoloskee in Florida and the lower Florida Keys west of the west end of the Seven Mile Bridge

• Hurricane Watch: Englewood to Indian Pass in Florida, including Tampa Bay

• Storm Surge Watch: Chokoloskee to Indian Pass in Florida, including Tampa Bay

Authorities will likely issue new warnings and update existing advisories throughout the system's progression in the coming hours and days.

The system is forecast to produce rainfall of 7.5-15 cm (3-6 inches), with locally higher amounts of 25 cm (10 inches), across portions of western Cuba and across portions of the west coast of Florida, the Florida Panhandle, and southern Georgia Aug. 29-30. Rainfall of 2.5-7.5 cm (1-3 inches), with locally higher amounts of 12.5 cm (5 inches), is forecast across the eastern Yucatan, Mexico. Heavy rainfall is also likely across portions of the Carolinas Aug. 30-31.

Dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. In Florida, the water could reach 2.1-3.4 meters (7-11 feet) from Aucilla River to Chassahowitzka, 1.8-2.7 meters (6-9 feet) from Chassahowitzka to Anclote River, and 1.2-2.1 meters (4-7 feet) from Ochlockonee River to Aucilla River, Anclote River to Middle of Longboat Key, and Tampa Bay. Smaller amounts are forecast across coastal areas of Florida. Storm surge will raise water levels by as much as 1.2-1.8 meters (4-6 feet) above normal tide levels along the southern coast of Pinar del Rio, Cuba. Large waves are likely near the coast.

Authorities in Florida have issued a state of emergency for 33 out of 67 counties Aug. 26 in advance of the storm. Parts of Hernando County are under voluntary evacuation orders.

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
Cuba Instituto de Meteorologia
Mexican National Meteorological Service (SMN)
US National Weather Service