Philippine Sea: Typhoon Usagi tracking west-northwestward toward the northeastern Philippines as of late Nov. 13 /update 3

Typhoon Usagi (known in the Philippines as Ofel) is tracking west-northwestward in the Philippine Sea toward Luzon in the Philippines late Nov. 13. As of 23:00 PHT, the system's center of circulation was approximately 494 km (307 miles) east-northeast of Manila, Philippines.

Forecast models indicate that the weather system will strengthen into a super typhoon as it tracks northwestward toward the far northeastern Philippines late Nov. 13-early Nov. 14, before making a close approach to northeastern Cagayan Province during the afternoon of Nov. 14 and then making landfall over Camiguin Island in the Babuyan Islands during the evening of Nov. 14. The storm is likely to weaken as it tracks north-northwestward and makes a close approach to Batanes Province during the morning of Nov. 15. Usagi is forecast to weaken into a tropical storm as it turns to track north-northeastward and makes a close approach to the southern tip of Taiwan during the afternoon of Nov. 16. The storm is then likely to weaken further as it tracks northeastward off the eastern coast of Taiwan Nov. 17-18. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

As of late Nov. 13, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) has issued a tropical cyclone bulletin advising that the system will bring strong winds and rough seas to northern and central Luzon. The following Tropical Cyclone Warning Signals (TCWS) are in place:

• TCWS 2 (the second lowest level on a five-tier scale): Cagayan including the Babuyan Islands, northern and central Isabela, Apayao, and northern Ilocos Norte provinces.

• TCWS 1: Batanes, the rest of Isabela, Quirino, northern Nueva Vizcaya, Kalinga, Abra, Mountain Province, Ifugao, the rest of Ilocos Norte, and northern Aurora provinces.

A separate weather advisory for heavy rainfall due to the storm is also in place. Rainfall of more than 20 cm (8 inches) is forecast over Isabela and Cagayan provinces Nov. 13-14 and Batanes and Cagayan provinces Nov. 14-15. Totals of 10-20 cm (4-8 inches) are forecast over Apayao and Kalinga Nov. 13-14 and Ilocos Norte Nov. 14-15. Lesser totals of 5-10 cm (2-4 inches) are forecast over other parts of the eastern and northern Philippines Nov. 13-16, with some of the later rainfall associated with the arrival of another storm system named Man-yi.

Authorities have preemptively evacuated residents in hazardous areas across the Cordillera Administrative, Ilocos, and Cagayan Valley regions. Classes have been suspended at schools in parts of Cagayan Valley Region Nov. 13 due to the approach of the storm system.

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, 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 amongst 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.