Philippine Sea: Typhoon Rai tracking westward in the Philippine Sea Dec. 15; landfall forecast over Caraga Region, Philippines, early Dec 16 /update 3

Event

Typhoon Rai (known locally in the Philippines as Odette) is tracking westward in the Philippine Sea early Dec. 15. As of 11:00 PHT, the storm's center of circulation was approximately 291 km (181 miles) northwest of Koror, Palau. Forecast models indicate the system will continue to track westward toward the Philippines and make landfall over the northern Caraga Region early Dec. 16. The system will track across the central Philippines through Dec. 17 and make further landfall over parts of the Eastern and Central Visayas and Mimaropa regions. The storm system is forecast to maintain typhoon strength as it enters the South China Sea early Dec. 18 and gradually turns to track northwestward toward southern China. Some uncertainty remains in the track and intensity forecast, and changes could occur over the next few days.

Government Advisories
As of Dec. 15, the Palau National Weather Service continues to issue hazardous surf and high surf advisories, warning of hazardous marine conditions to small vessels, through Dec. 16. The Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) has issued Tropical Cyclone Wind Signals (TCWS) 2 across eastern Surigao del Norte and Surigao del Sur provinces. TCWS 1 is in effect across the rest of the Caraga Region, Central Visayas, Eastern Visayas, Western Visayas, southern Bicol Region, and northern Northern Mindanao regions. Authorities have warned of light to moderate rains over Dinagat Islands, Southern Leyte, Surigao del Norte, and Surigao del Sur provinces through early Dec. 16. There is a minimal to moderate risk of storm surge of up to 2 meters (6.5 feet) through early Dec. 17; flooding in low-lying coastal areas of the Visayas as well as Camiguin, Dinagat Islands, southern Masbate, Misamis Occidental, Misamis Oriental, Surigao del Norte, and Surigao del Sur provinces is possible. 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. Localized evacuations could occur if weather conditions prove particularly hazardous.

Hazardous Conditions
Typhoon Rai will likely bring heavy rainfall, strong winds, and rough seas to coastal areas of Palau over the coming days and will start to affect the eastern Philippines from Dec. 15. 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 the 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 through at least Dec. 19. 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 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 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 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. Keep any necessary medications in a waterproof container.

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
Palau National Weather Service Facebook
Philippine Atmospheric Geophysical and Astronomical Services Administration