Philippine Sea: Tropical Storm Usagi tracking northwestward toward the Philippines as of early Nov. 12 /update 1

Tropical Storm Usagi (known in the Philippines as Ofel) is tracking northwestward in the Philippine Sea toward Luzon in the Philippines early Nov. 12. As of 11:00 PHT, the system's center of circulation was approximately 1,381 km (858 miles) east of Manila, Philippines.

Forecast models indicate that the weather system will strengthen into a typhoon over the coming hours before continuing northwestward across the Philippine Sea through Nov. 13 and making a close approach to Cagayan Province in the Philippines early Nov. 14. Usagi is forecast to make landfall over Batanes Province, Philippines, early Nov. 15 before making a close approach to Pingtung County in Taiwan the afternoon of Nov. 15 and tracking northward parallel to the coast through early Nov. 16. The storm is then likely to turn to track northeastward and make a close approach to the Yaeyama Islands, Okinawa Prefecture, Japan, early Nov. 17, passing just southeast of the islands. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

A weather advisory for heavy rainfall due to the storm is also in place. Rainfall of 10-20 cm (4-8 inches) is forecast over Cagayan and Isabela provinces Nov. 14. Lesser totals of 5-10 cm (2-4 inches) are forecast over Ilocos Norte, Cagayan, and Batanes provinces Nov. 12 and Apayao and Kalinga provinces Nov. 14.

Much of the northern and central Philippines is still recovering from the passage of Tropical Storm Trami (named Kristine in the Philippines), which made landfall in Divilacan Town, Isabela Province, at around 00:30 Oct. 24, Tropical Storm Kong-rey (named Leon in the Philippines), which made a close approach to northeastern Luzon Oct. 30-31, Tropical Storm Yinxing (named Marce in the Philippines), which passed over the north coast of Luzon Nov. 7, and most recently Typhoon Toraji (named Nika in the Philippines), which made landfall near Dilasag in Aurora Province early Nov. 11. The succession of tropical systems has caused widespread flooding, damage, and associated disruptions across the region. More than 280,000 people remain evacuated following damage caused by the storms, with the worst affected Cagayan Province. Further severe weather associated with Tropical Storm Usagi will likely lead to more disruptions and hamper recovery efforts.

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, rendering 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.