Gulf of Mexico: Tropical Storm Idalia moving northward over the Gulf of Mexico late Aug. 28 /update 3

Event

Tropical Storm Idalia is slowly tracking north over the Gulf of Mexico late Aug. 28. As of 22:00 CDT, the system's center of circulation was approximately 15 km (10 miles) northwest of the western tip of Cuba.

Forecast models indicate that the storm will strengthen into Category 3 hurricane while turning gradually to track northeastward across the Gulf of Mexico through Aug. 29 before making landfall over Florida's Gulf Coast in the US early Aug. 30. After landfall, the system will likely weaken rapidly into a tropical storm as it crosses northern Florida and southeastern Georgia through the evening of Aug. 30 before entering the North Atlantic Ocean. Idalia is likely to weaken further as it tracks northeastward along the coast of the Carolinas through Aug. 31 before tracking eastwards away from land into Sept. 2. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.

As of late Aug. 28, authorities have issued the following coastal watches and warnings:

• Hurricane Warning: Cuban province of Pinar del Rio; Florida, US, from the middle of Longboat Key northward to Indian Pass, including Tampa Bay

• Hurricane Watch: Florida, US, from Englewood to the middle of Longboat Key

• Tropical Storm Warning: Yucatan Peninsula in Mexico from Tulum to Rio Lagartos, including Cozumel; the Isle of Youth in Cuba; Dry Tortugas, Chokoloskee northward to the middle of Longboat Key, and west of Indian Pass to Mexico Beach in Florida, US; Sebastian Inlet, Florida to Altamaha Sound, Georgia

• Tropical Storm Watch: Lower Florida Keys west of the west end of the Seven Mile Bridge; Altamaha Sound northward to South Santee River, South Carolina

• Storm Surge Warning: Florida, US, from Englewood northward to the Ochlockonee River, including Tampa Bay

• Storm Surge Watch: Chokoloskee northward to Englewood, including Charlotte Harbour; mouth of the St. Mary's River to South Santee River South Carolina, US

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 10-17 cm (4-7 inches), with locally higher amounts of 25 cm (10 inches), across portions of western Cuba. In parts of the west coast of Florida, the Florida Panhandle, southeast Georgia, and the eastern Carolinas, rainfall totals will be 10-20 cm (4-8 inches), with locally higher amounts in northern Florida of up to 30 cm (12 inches) Aug. 29-31.

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 2.4-3.7 meters (8-12 feet) from Aucilla River to Chassahowitzka, 1.8-2.7 meters (6-9 feet) from Chassahowitzka to Anclote River, and 1.5-2.4 meters (5-8 feet) from Ochlockonee River to Aucilla River. 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.

Tornadoes are possible along the west central Florida coast Aug. 29, with the tornado threat spreading northward into the Florida Big Bend late Aug. 29. Swells, which are likely to cause life-threatening surf and rip current conditions, are affecting portions of the southern coast of Cuba and eastern Yucatan, Mexico, and are forecast to spread northward along the eastern Gulf Coast over the coming days.

Authorities in Florida have expanded the state of emergency to include 47 out of the state's 67 counties in advance of the storm and federal authorities approved the state's emergency declaration Aug. 28. Jacksonville, St. Petersburg, and Tampa cities and Pinellas County also declared states of emergency. Evacuation orders are in place for hundreds of thousands of people across 15 counties in Florida, including Hernando, Hillsborough, Lee, Manatee, Pasco, Pinellas, and Taylor counties.

Tampa International Airport (TPA) is scheduled to close Aug. 29, while St. Pete-Clearwater International Airport (PIE) is scheduled to close the afternoon of Aug. 29 and reopen the afternoon of Aug. 30. The Pinellas Suncoast Transit Authority is scheduled to suspend all transit services the evening of Aug. 29 until further notice. The cities of St. Petersburg, Largo, Pinellas Park, and Temple Terrace have closed offices and suspended transport and county services Aug. 29-30. Three Tampa Bay hospitals were evacuated and closed Aug. 28; patients at HCA Florida Trinity West Hospital in New Port Richey, HCA Florida West Tampa Hospital, and HCA Florida Pasadena Hospital were transferred to other facilities as a precaution. Most schools in the affected area are closed over the coming days.

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