North Pacific Ocean: TD 28W forms and is tracking westward in the North Pacific Ocean early Dec. 13; close approach to Palau likely early Dec. 15

Event

Tropical Depression (TD) 28W has formed and is tracking westward in the North Pacific Ocean Dec. 13. As of 12:00 PWT, the storm's center of circulation was approximately 630 km (390 miles) southeast of Yap in the Federated States of Micronesia. Forecast models indicate the system will continue tracking westward in the North Pacific Ocean as it strengthens rapidly into a tropical storm over the coming days; a close approach to northern Babeldaob Island, Palau, is likely early Dec. 15. The system is forecast to further strengthen into a typhoon as it continues westward before making landfall over Surigao del Sur Province, Philippines, late Dec. 16. The storm will likely track westwards across the Caraga, Northern Mindanao, Central Visayas, and Western Visayas regions through Dec. 17 before making another landfall over Palawan Province early Dec. 18. Some uncertainty remains in the track and intensity forecast, and changes could occur over the next few days.

Government Advisories
As of Dec. 13, the Palau National Weather Service has issued a tropical storm condition 2 for the Republic of Palau. Tropical storm conditions with winds of 65-120 kph (39-73 mph) are likely Dec. 14. High surf advisories are in place for the north-facing reefs with hazardous marine conditions for small crafts. Coastal inundation of up to 0.6 meters (2 feet) is also likely through Dec. 14. Authorities will likely 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. The possibility of localized evacuations cannot be discounted if weather conditions prove particularly hazardous.

Hazardous Conditions
TD 28W is likely to bring heavy rainfall, strong winds, and rough seas to coastal areas of Palau over 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 the heavy rain, flooding, and storm surge, the storm could produce damaging wind gusts. Tropical storm-force gusts in excess of 50 knots (90 kph, 60 mph) cannot be ruled out. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are possible.

Transport
In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger localized business, transport, and utility disruptions through at least Dec. 18. 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