Caribbean Sea: Potential Tropical Cyclone Nine tracking northward across the northwestern Caribbean Sea as of Sept. 23

Potential Tropical Cyclone Nine is tracking northward across the northwestern Caribbean Sea Sept. 23. As of 11:00 EDT, the system's center of circulation was approximately 205 km (130 miles) south-southwest of Grand Cayman, Cayman Islands.

Forecast models indicate that the storm will strengthen into a tropical depression as it tracks north-northwestward in the Caribbean Sea Sept. 23, before strengthening further into a tropical storm as it turns to track northwestward away from the Cayman Islands late Sept. 23-24. The system is expected to become a Category 1 hurricane as it tracks north-northwestward through the Yucatan Channel late Sept. 24-early Sept. 25. The storm is then expected to strengthen into a Category 2 hurricane as it tracks northward and then north-northeastward over the eastern Gulf of Mexico Sept. 25-early Sept. 26, before making landfall around the Big Bend area of Florida during the afternoon Sept. 26. After landfall, the system is forecast to weaken into a tropical storm as it tracks north-northeastward over Georgia late Sept. 26-early Sept. 27. The storm system will dissipate as it turns to track northwestward over far southwestern North Carolina, eastern Tennessee, central Kentucky, and into southern Indiana through early Sept. 28. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming hours and days.

As of Sept. 23, authorities have issued the following watches and warnings:

Hurricane Watch

• Cabo Catoche to Tulum, Mexico

• Pinar del Rio Province, Cuba

Tropical Storm Warning

• Rio Lagartos to Tulum, Mexico

• Artemisa and Pinar del Rio provinces and the Isle of Youth, Cuba

Authorities will likely update and extend the coverage of the weather advisories over the coming hours and days as the storm approaches.

Hurricane conditions are possible within the watch areas by early Sept. 25 and tropical storm conditions are expected in the warning areas from Sept. 14. Storm surge could raise water levels by as much as 0.6-1.2 meters (2-4 feet) above normal tide levels in areas of onshore winds along the southern coast of Pinar del Rio, Cuba, including the Isle of Youth.

The storm is forecast to generate rainfall amounts of 10-20 cm (4-8 inches) with isolated higher totals over 30 cm (12 inches) across parts of western Cuba and the Cayman Islands. Amounts of 5-10 cm (2-4 inches) with isolated totals over 15 cm (6 inches) are expected over the eastern Yucatan Peninsula, Mexico. This rainfall will bring a risk of flash and urban flooding and minor river flooding. Heavy rainfall is expected to spread into parts of the southeastern US from Sept. 25 and continue through at least Sept. 27.

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.

Inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary port closures are also possible. Stagnant pools of water during and after flooding increase 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.