Philippine Sea: Super Typhoon Rai tracking westward in the Philippine Sea Dec. 16; landfall forecast over northern Caraga Region, Philippines /update 5

Event

Super Typhoon Rai (known locally in the Philippines as Odette) was tracking westward in the Philippine Sea early Dec. 16. As of 08:00 PHT, the storm's center of circulation was approximately 890 km (554 miles) southeast of Manila, Philippines. Forecast models indicate the system will slightly weaken into a typhoon over the coming hours as it tracks westward and makes landfall over the northern Caraga Region the afternoon of Dec. 16. The system will weaken further as it tracks across the central Philippines and makes further landfalls over parts of far southern Eastern Visayas, Central Visayas, and Western Visayas regions Dec. 16-17. After crossing the Sulu Sea Dec. 17, Rai is forecast to make landfall over northern Palawan island later the same day. The system will maintain typhoon strength as it enters the South China Sea and will likely strengthen as it gradually turns northwestward, passing west of the Paracel Islands early Dec. 20. Rai is forecast to shift northeastward toward southern China and weaken rapidly into a tropical storm, passing southeast of Hainan Province, China, early Dec. 21. Some uncertainty remains in the track and intensity forecast, and changes could occur over the next few days.

Authorities have ordered preemptive evacuations for at least 45,000 people in the Caraga Region and Eastern Visayas regions of the Philippines, including almost 30,000 residents across Eastern Samar Province, ahead of the storm. Evacuations are also underway in Capiz and Cebu provinces. Further evacuations are likely across the central Philippines in the coming hours and days as Typhoon Rai impacts the region.

Government Advisories
The Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) has issued the following warnings:

• Tropical Cyclone Wind Signal (TCWS) 3: Dinagat Islands, Surigao del Norte, northern Agusan del Norte, and northern Surigao del Sur provinces in Mindanao as well as Southern Leyte, the southern areas of Leyte, central and southern Cebu including Camotes Islands, and Bohol provinces in the Visayas.

• TCWS 2: Sorsogon, Masbate, southern Oriental Mindoro, and Romblon provinces in Luzon, Northern Samar, Eastern Samar, Samar,Biliran, the rest of Leyte, the rest of Cebu including Bantayan Islands, Negros Oriental, Negros Occidental, Siquijor, Guimaras, Iloilo, Antique, Capiz, and Aklan provinces in the Visayas, and the rest of Surigao del Sur, the rest of Agusan del Norte, Agusan del Sur, northern Bukidnon, Misamis Oriental, Camiguin, northern Misamis Occidental, and far northern Zamboanga del Norte provinces in Mindanao.

• TCWS 1: Catanduanes, Camarines Norte, Camarines Sur, Albay, Sorsogon, Marinduque, southern Quezon, Batangas, Oriental Mindoro, Occidental Mindoro, and mainland Palawan provinces in Luzon and northern Davao Oriental, northern Davao de Oro, northern Davao del Norte, rest of Misamis Occidental, the rest of Bukidnon, Lanao del Norte, Lanao del Sur, northern Zamboanga del Norte, northern Zamboanga del Sur, and northern Zamboanga Sibugay provinces in Mindanao.

Authorities have warned of heavy to torrential rains over Caraga, Camiguin, Central Visayas, Misamis Oriental, Negros Occidental, and Southern Leyte provinces while moderate to heavy rain is likely across Davao Oriental, Davao de Oro, Davao del Norte, southern Eastern Samar, Lanao del Sur, Leyte, the rest of Northern Mindanao, southern Samar, and Zamboanga del Norte provinces through early Dec. 17. There is a moderate to high risk of storm surge of up to 3 meters (10 feet) which may cause flooding in low-lying coastal areas of the Central Visayuas region as well as Northern Mindanao, Iloilo, Guimaras, Negros Occidental, Eastern Samar, Southern Leyte, Dinagat Islands, Surigao del Norte, Surigao del Sur, Agusan del Norte, northern Palawa, Antique, southern Samar, southern Leyte, and southern Davao Oriental provinces.

Authorities will probably issue new warnings or update existing advisories throughout the system's progression in the coming days. Weather warnings could remain active even after the system's immediate threat has diminished, as some areas may still be highly susceptible to rain-induced hazards. Officials may announce additional evacuations if weather conditions prove particularly hazardous.

Hazardous Conditions
Super Typhoon Rai will likely bring heavy rainfall, strong winds, and rough seas to most of the Visayas, southern Luzon, and northern Mindanao regions of the Philippines in the coming days. Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, and rivers, as well as in urban areas with easily overwhelmed stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Rain-induced landslides are possible in steeply sloped terrains. Flooding could isolate some communities for several days. Prolonged sea swells and storm surge generated by the system could result in coastal flooding as the system approaches land. Persistent onshore flow could make it difficult for surge to recede and for water levels to decrease in coastal river catchments.

In addition to forecast heavy rain, flooding, and storm surge, the storm could produce damaging wind gusts. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are possible.

Transport
Inclement weather associated with the storm could trigger localized business, transport, and utility disruptions. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Areal flooding in urban locations could also result in severe traffic congestion, while strong winds will pose a hazard to high-profile vehicles. Heavy rain and low visibility may trigger flight disruptions at regional airports.

Disruptions triggered by inclement weather and resultant hazards, such as flooding, could persist well after weather conditions have improved. If there is severe damage to infrastructure, repair or reconstruction efforts may exacerbate residual disruptions.

Advice

Activate contingency plans in areas where officials forecast tropical storm or typhoon conditions. Heed all evacuation orders. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the high 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 any 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
Philippine Atmospheric, Geophysical and Astronomical Services Administration