Indian Ocean: Tropical Cyclone Chido tracking westward toward Agalega, Mauritius, Dec. 11 /update 2

Tropical Cyclone Chido is tracking westward across the Indian Ocean toward Agalega, Mauritius, on Dec. 11. As of 13:00 MUT, the system was around 1,072 km (666 miles) north of Port Louis, Mauritius.

Forecast models indicate that the storm will strengthen as it continues westward and passes just south of Agalega, Mauritius, late Dec. 11. Chido is expected to briefly strengthen into an intense tropical cyclone as it tracks westward and then west-southwestward away from Agalega Dec. 12, before weakening back into a tropical cyclone and making landfall over northern Diana Region in Madagascar late Dec. 13-early Dec. 14. The system is likely to weaken into a severe tropical storm as it tracks southwestward across the Mozambique Channel Dec. 14-15, passing south of Mayotte late Dec. 14-early Dec. 15. The storm will continue to weaken before making another landfall over Nampula Province in Mozambique late Dec. 15-early Dec. 16. After landfall, Chido is expected to weaken rapidly into a zone of disturbed weather and dissipate as it tracks southwestward inland over southern Nampula during the morning Dec. 16. Some uncertainty remains in the track and intensity forecast; changes could occur in the coming hours and days.

The Mauritius Meteorological Services (MMS) has issued a special weather bulletin warning that a heavy rain warning, a strong wind warning, and a heavy swell warning are in force in Agalega. The weather will be cloudy to overcast with scattered moderate to heavy showers with thunderstorms, becoming more intense through the evening. During the thundery showers, the public is advised to stay indoors, to avoid the plains, and to avoid taking shelter under trees. Winds will strengthen over the coming hours, with gusts of up to 120 kph (75 mph) possible from late Dec. 11. The sea will become increasingly rough with swells of around 6 meters (20 feet); the public is advised not to venture at sea and to avoid the beaches. As Chido approaches Agalega, storm surges may influence the coast, with waves reaching up to 8 meters (26 feet).

Meteo Madagascar has issued a yellow cyclone warning (the middle level on a three-tier scale) across the Diana Region and Vohemar District in the Sava Region and green cyclone warnings for the rest of Sava and much of Sofia regions. Yellow strong wind and heavy swell warnings are in place for northern coastal areas.

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. 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. Stagnant pools of water during and after flooding increase insect- and waterborne diseases, such as dengue fever, cholera, and malaria. Raw sewage and other hazardous materials mixed with floodwaters pose a serious health threat.