Philippines: Super Typhoon Usagi tracking north-northwestward near the Babuyan Islands as of late Nov. 14 /update 5

Typhoon Usagi (known in the Philippines as Ofel) is tracking north-northwestward in the Luzon Strait close to the Babuyan Islands late Nov. 14, after making landfall near Baggao in Cagayan Province at around 13:30 Nov. 14. As of 23:00 PHT, the system's center of circulation was approximately 470 km (292 miles) north of Manila, Philippines.

Forecast models indicate that the system will pass through the Babuyan Islands in the coming hours before weakening as it tracks north-northwestward across the Luzon Strait to the west of Batanes Province through Nov. 15. Usagai is expected to weaken into a tropical storm as it tracks north-northeastward late Nov. 15-early Nov. 16 before making landfall over Pingting County, Taiwan, during the morning Nov. 16. The system is expected to continue to weaken as it tracks slowly north-northeastward then northward skirting along the coasts of Pingting and Taitung counties Nov. 16-17 before turning westward late Nov. 17 and tracking across southern Taiwan Nov. 18. Usgai is then expected to weaken into a tropical depression as it tracks southwestward and exits Taiwan into the South China Sea near Kaoshiung early Nov. 19. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

As of late Nov. 14, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) has issued a tropical cyclone bulletin advising that the system will continue to bring strong winds and rough seas to northern and eastern Luzon. There is a high risk of life-threatening storm surge with peak heights exceeding 3 meters (0.9 feet) in the next 48 hours over the low-lying or exposed coastal localities of Batanes, Ilocos Norte, Ilocos Sur, Cagayan including Babuyan Islands, Isabela, and northern Aurora provinces. The following Tropical Cyclone Warning Signals (TCWS) are in place:

• TCWS 4 (the second highest level on a five-tier scale): The Babuyan Islands and northern and eastern mainland Cagayan Province.

• TCWS 3: Batanes, the rest of Cagayan, northern Isabela, northern Apayao, and northern Ilocos Norte provinces.

• TCWS 2: Eastern and western Isabela, northeastern the rest of Apayao, Kalinga, northeastern Abra, eastern Mountain Province, and the rest of Ilocos Norte provinces.

• TCWS 1: The rest of Isabela, northern Quirino, northern Nueva Vizcaya, the rest of Mountain Province, Ifugao, the rest of Abra, northern Benguet, Ilocos Sur, northern La Union, and northern Aurora provinces.

A separate weather advisory for heavy rainfall due to the storm is also in place. Rainfall totals of 10-20 cm (4-8 inches) are forecast over Batanes, Cagayan, Ilocos Norte, and Apayao provinces and 5-10 cm (2-4 inches) over Abra, Kalinga, Mountain Province, and Isabela provinces Nov. 14-15. Further heavy rainfall is forecast over parts of the eastern and northern Philippines late Nov. 15-17, but this is likely more associated with the arrival of another storm system named Man-yi.

The Taiwan Central Weather Administration has issued a sea and land typhoon warning covering southern areas of Taiwan and southern coastal waters. Strong wind advisories and swell warnings are also in place for parts of southern Taiwan.

Authorities in the Philippines preemptively evacuated tens of thousands of residents in hazardous areas across the Cordillera Administrative, Ilocos, and Cagayan Valley regions ahead of the arrival of Usagi. Classes are suspended at schools in parts of Cagayan Valley and Cordillera Administrative regions.

Much of the northern and central Philippines are still recovering from previous storms, including 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 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. Tens of thousands of people remain evacuated following damage caused by the storms, with parts of Cagayan Province among the worst affected areas. Further severe weather associated with Typhoon 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.