North Atlantic Ocean: Tropical Storm Gaston tracking west-southwestward near Azores, Portugal, Sept. 24 /update 3

Event

Tropical Storm Gaston is tracking west-southwestward in the central North Atlantic Ocean Sept. 24. As of 15:00 GMT, the storm's center of circulation was approximately 195 km (120 miles) west-southwest of Faial Island in the central Azores.

Forecast models indicate that the system will maintain its strength as it transitions into a post-tropical cyclone and tracks westward around 150 km (93 miles) south of the western Azores late Sept. 24-early Sept. 25. The post-tropical storm will then weaken as it tracks westward and then southwestward away from the Azores Sept. 25-28, posing no further threat to land before dissipating. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

As of 15:00 GMT Sept. 24, authorities had issued tropical storm warnings for Flores and Corvo islands in the western Azores and Faial, Pico, Sao Jorge, Graciosa, and Terceira islands in the central Azores. The Portuguese Institute for Sea and Atmosphere (IPMA) has issued yellow heavy rainfall and rough sea warnings (the lowest level on a three-tier scale) for the western Azores Sept. 24-25. Yellow strong wind warnings have been issued for the western Azores Sept. 24-25 and the central Azores Sept. 24. Officials could issue new warnings and/or watches in response to the developing system in the coming hours.

Forecast models indicate the storm will bring additional rainfall accumulations of 2.5-5 cm (1-2 inches) with locally higher amounts of 7.5 cm (3 inches) across the central and western Azores. The heavy rainfall could trigger flooding and landslides. Swells generated by Gaston will affect the Azores through late Sept. 24 and are likely to cause life-threatening surf and rip current conditions.

Officials in the Azores have suspended port operations across Corvo and Flores islands in the western Azores as of Sept. 24 due to the passing of the storm system. Authorities have not reported any casualties or major damage associated with the storm as of Sept. 24.

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.

The inclement weather could trigger localized business, transport, and utility disruptions, rendering some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Raw sewage and other hazardous materials mixed with floodwaters pose a serious health threat.

Advice

Activate contingency plans in areas where officials forecast tropical storm conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the 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 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

US National Hurricane Center
Portuguese Institute for Sea and Atmosphere (IPMA)