Fiji, Vanuatu: Tropical Low Four in the South Pacific ocean set to strengthen considerably in the coming days, as of Dec. 12 /update 1

Event

Tropical Low Four is tracking between Fiji and Vanuatu in the South Pacific Ocean Dec. 12. As of 1800 FJT, the storm's center of circulation was approximately 500 km (310 miles) northwest of Suva, Fiji. Forecast models indicate the storm will strengthen into a Category-1 tropical cyclone by early Dec. 13 as it tracks westward. The system is forecast to continue strengthening over the coming days, possibly reaching Category-3 tropical cyclone status by Dec. 16. Currently, no landfall is forecast over the coming days; however, impacts associated with Tropical Low Four will likely be felt across Fiji and Vanuatu through at least Dec. 17. Significant uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

Government Advisories
As of 1800 FJT, authorities with the Vanuatu Meteorological Services have warned of moderate rainfall that could result in flooding over low-lying areas, including rivers. Additionally, the Fiji Meteorological Service has issued a tropical cyclone warning. 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
Tropical Low Four will bring heavy rainfall, strong winds, and rough seas to areas of Vanuatu and Fiji through at least Dec. 17. Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, and rivers, as well as in urban areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Rain-induced landslides cannot be discounted in steeply sloped terrains. Flooding could isolate some communities for several days. Coastal flooding and abnormally high tides are possible along Vanuatu's eastern and Fiji's northern and western coasts.

In addition to the heavy rain, flooding, and storm surge, the system may produce damaging wind gusts as it approaches landfall. 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. 17. Floodwaters and debris flows may render some bridges 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 caused 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 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
Vanuatu Meteorological Services
Fiji Meteorological Service