Coral Sea: Tropical Low 23 forms in the Coral Sea April 4; close approach to New Caledonia as a tropical cyclone expected April 6-7

Event

A tropical depression in the Coral Sea has strengthened into a tropical low, currently named Tropical Low 23, April 4 and is forecast to strengthen further into a tropical cyclone as it makes a close approach to New Caledonia April 6-7. The storm system is tracking southwestward and as of 17:00 NCT the storm's center of circulation was approximately 613 km (381 miles) south-southeast of Port Vila, Vanuatu. Forecast models indicate the system will strengthen into a Category 1 and then a Category 2 Tropical Cyclone as it tracks southward and then southeastward April 5-6, making a close approach to New Caledonia's Belep Island and northern Grande Terre April 6. The storm system is then forecast to weaken slightly back to a Category 1 Tropical Cyclone as it tracks off the west coast of Grande Terre April 7, gradually moving further away from the territory before becoming a subtropical low pressure system as it approaches the Tasman Sea April 9. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

Government Advisories
As of late April 4, Meteo France Nouvelle Caledonie has warned that cyclonic pre-alert status has been triggered across the territory due to the approaching storm system. Weather conditions are expected to deteriorate from late April 4-5 in the north of the territory. Winds of 46-56 kph (29-35 mph) are likely across Belep and the far north of the territory, with gusts of up to 85 kph (53 mph). Rainfall is expected to gradually increase in northern and eastern coastal areas, with 10-15 cm (4-6 inches) of rainfall expected in northeastern areas.

The Vanuatu Meteorology and Geo-Hazards Department has stated that Tropical Low 23 does not pose any significant threat to the islands as yet; however, isolated heavy rainfall is expected in northern and central islands and a severe weather warning has been issued accordingly for these areas. Flash flooding is possible in low-lying and coastal areas during periods of intense rainfall.

Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days.

Hazardous Conditions
Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. Localized evacuations, flash flooding, and landslides are possible if weather conditions prove hazardous.

Transport
The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at airports in the region, including La Tontouta International Airport (NOU) in Noumea, and temporary closures of ports are also possible. Stagnant pools of water during and after flooding increase insect- and waterborne diseases, such as dengue fever and cholera. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.

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

Meteo France Nouvelle Caledonie (French)
Vanuatu Meteorology and Geo-Hazards Department