Gaston (2016)

A strong tropical wave moved off the west coast of Africa on 20 August and developed into Tropical Depression Seven on 22 August about 265 nautical miles southwest of the southern Cabo Verde Islands. The system became Tropical Storm Gaston later that day, moved generally west-northwest and then northwest, briefly weakened below hurricane strength on 25 August, re-intensified, and underwent rapid strengthening from 27–29 August. Gaston drifted nearly stationary about 490 n mi east-southeast of Bermuda, then moved north and east-northeast, and finally turned toward the Azores before becoming post-tropical and dissipating by 3 September.

Gaston did not make landfall in the Americas. Its closest approach to land occurred when it passed very near Flores Island in the western Azores as a post-tropical cyclone on 2 September 2016; at that time it had already weakened to post-tropical status with 45‑kt (about 52 mph) winds. Tropical storm watches and warnings were issued for the central and western Azores ahead of the system on 31 August–1 September.

The hurricane reached its maximum analyzed intensity on 29 August with peak sustained winds of 105 knots (about 120 mph) and a minimum central pressure of 955 mb, making it a Category 3 major hurricane on the Saffir–Simpson scale. Gaston later briefly re-attained similar peak winds (105 kt) around 31 August before weakening while moving northeastward.

When Gaston passed the Azores as a post-tropical cyclone it produced tropical-storm-force winds and modest rainfall. Observations show peak wind gusts of 45 kt (about 52 mph) at Flores and at the Horta Observatory on Faial Island. Reported sustained winds at some Azores stations reached into the upper 20s to low 30s knots (e.g., 31 kt at Corvo). Rain totals in the western Azores were small; for example, 0.35 inch at Flores and 0.41 inch at Pico.

No damage or casualties were reported in association with Gaston. The storm was notable as a classic Cape Verde hurricane that underwent rapid intensification twice and became a major hurricane over the central Atlantic well away from land. Forecasts and watches for Gaston were generally accurate: the system’s formation was well predicted, and the National Hurricane Center’s track and intensity forecasts for Gaston performed better than recent averages.