South China Sea: Tropical Storm Nalgae is tracking north-northwest across the South China Sea early Oct. 31 /update 6

Event

Tropical Storm Nalgae, known in the Philippines as Paeng, is tracking north-northwest across the South China Sea early Oct. 31. The storm previously made landfall over Batangas Province in the Philippines the afternoon of Oct. 29 and earlier landfalls over the southern tip of Catanduanes Island and Camarines Sur Province early Oct. 29. As of 11:00 CST, the system's center of circulation was approximately 481 km (299 miles) west-northwest of Manila, Philippines.

Forecast models indicate that the storm will strengthen into a typhoon over the coming hours while gradually turning to track northwards. The storm is forecast to weaken again into a tropical storm by early Nov. 2 as it gradually turns to track westward towards southern mainland China. Nalgae is likely to weaken into a tropical depression early Nov. 4 before making landfall over far northern Hainan Province, China, late Nov. 4. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

As of early Oct. 31, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) has warned of moderate to heavy rainfall over Bataan, Batanes, and Zambales provinces and light to moderate rain over the rest of central and northern Philippines through the afternoon of Oct. 31. Tropical Cyclone Wind Signal 1 remains in place over western Luzon.

The China Meteorological Administration has issued a blue (lowest-level on a four-tier scale) typhoon warning; heavy rainfall is forecast over the southern coast of Fujian and the eastern coast of Guangdong through the afternoon of Nov. 1.

The Taiwan Central Weather Bureau has issued purple extremely torrential rain advisories (highest level on a four-tier scale) over southern Yilan County and red torrential rain advisories across northern Taipei City and the rest of Yilan County. Orange extremely heavy rain advisories are in place across Hualien and Taitung counties as well as Keelung and New Taipei cities while yellow heavy rain advisories have been issued for Hsinchu, Miaoli, and Pingtung counties as well as Taichung and Taoyuan cities. Officials will likely update and extend the coverage of the relevant weather alerts over the coming days as the system progresses.

Authorities in the Philippines declared a state of calamity for Aklan and Capiz provinces; authorities are likely to declare additional states of calamity over the coming hours and days. As of early Oct. 31, reports indicate that at least 98 people across the Philippines have died and 63 others are missing due to landslides and flooding. Authorities have pre-emptively evacuated more than 105,000 people from flood-prone areas in Luzon and Visayas. More than 975,000 people remain displaced across 4,024 evacuation centers.

Officials have canceled several flights through Ninoy Aquino International Airport (MNL) Oct. 31 due to adverse weather, including Bacolod (BCD), Cagayan de Oro (CGY), Caticlan (MPH), Cebu (CEB), Davao (DVO), Dumaguete (DGT), Iloilo (ILO), Kalibo⁣ (KLO), Puerto Princesa (PPS), Tacloban (TAC), and Tagbilaran (TAG).

Power outages are ongoing across portions of Aurora and Quezon provinces due to the storm. At least 689 houses were totally destroyed by the storm, and another 3,499 houses partially damaged. Classes remain suspended in parts of northern and central Philippines.

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.

The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Further flight disruptions at regional airports and temporary closures of ports are also possible. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.

Advice

Activate contingency plans in areas where officials forecast typhoon or tropical storm conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.

Resources

Joint Typhoon Warning Center
China Meteorological Administration
Philippine Atmospheric, Geophysical and Astronomical Services Administration
Taiwan Central Weather Bureau