Coral Sea: Tropical Cyclone 17P forms in the Coral Sea Jan. 31; likely to cause adverse weather in Vanuatu and New Caledonia from Feb. 1

Event

Category-1 Tropical Cyclone 17P has formed in the Coral Sea. As of 1100 NCT Jan. 31, the system's center of circulation was approximately 920 km (772 miles) east-northeast of Cairns, Australia. Forecast models suggest the storm will strengthen into a Category-3 Tropical Cyclone as it tracks in a southeastern direction, close to Vanuatu Feb. 1-2. The system will then weaken into a Category-2 cyclone and make a close approach to New Caledonia Feb. 3-4. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

Weather Warnings
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. Localized evacuations are possible if weather conditions prove particularly hazardous.

Hazardous Conditions
Tropical Cyclone 17P will likely bring heavy rainfall, strong winds, and rough seas to coastal areas in New Caledonia and Vanuatu 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 or a lack of stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Elevated water levels are likely in catchment areas where flood watches and warnings are in place. Rain-induced landslides could occur in steeply sloped terrains. Flooding could isolate some communities for several days. Prolonged swells and storm surge generated by the system will likely result in coastal flooding as the system approaches land.

In addition to the heavy rain, flooding, and storm surge, the storm will produce damaging wind gusts during its passage in the Coral Sea. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are possible, especially in Grande Terre, New Caledonia.

Transport
Inclement weather associated with the storm could trigger localized business, transport, and utility disruptions through at least Feb. 5. 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, including La Tontouta International Airport (NOU) in Noumea, New Caledonia. 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 cyclone 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: www.metoc.navy.mil/jtwc

Meteo New Caledonia (French): www.meteo.nc