Tropical Storm Bret was a short-lived tropical cyclone, and was the earliest named storm to develop in the Main Development Region of the Atlantic basin on record. Bret formed from a tropical wave that had exited off the coast of West Africa on June 12. The disturbance moved swiftly across the Atlantic for several days, steadily organizing despite its low latitude. On June 18, the organization increased enough for the National Hurricane Center (NHC) to begin issuing warnings disturbance while it was located southeast of the Windward Islands. The system continued to organize, and by the next day, it had developed into a tropical storm, the second of the 2017 Atlantic hurricane season. Bret continued moving swiftly to the west and struck Trinidad and Tobago early on June 20, before entering the Caribbean Sea, dissipating shortly afterwards.
Starting in the 2017 season, the NHC changed its policy to allow tropical storm watches and warnings to be issued for tropical disturbances that do not yet satisfy the definition of a tropical cyclone but are expected to in short order while posing the threat of tropical-storm-force winds to landmasses. Thus, on June 18, although the vigorous tropical wave—the precursor to Bret—did not meet formal classification standards, the NHC began issuing advisories on what was considered a potential tropical cyclone. Bret left about $3 million (2017 USD) in damage and two deaths, with both in Trinidad and Tobago.
Meteorological history
A tropical wave emerged into the Atlantic from the west coast of Africa at a low-latitude on June 13. Although the wave was initially accompanied by a large area of showers and thunderstorms, convection diminished later the following day. The National Hurricane Center (NHC) began discussing the system in its Tropical Weather Outlooks (TWO) while the wave was located well south of Cabo Verde on June 14, though any organization was expected to be slow as the system tracked swiftly westward. Deep convection flared sporadically as the wave moved westward under the influence of a mid-level ridge situated to the north during the next few days. On June 16, cloudiness associated with the feature began to show signs of organization. ASCAT data around 12:00 UTC on June 18 indicated that a broad low pressure area developed, but lacked a well-defined circulation. A large area of winds was noted just north of the broad low. At 21:00 UTC, the NHC issued their first-ever advisory on a potential tropical cyclone. Despite winds of tropical storm-force, it was inconclusive whether the system possessed a closed low-level circulation.
Convection continued to increase on June 19, and around 18:00 UTC, a reconnaissance aircraft investigating the low found a well-defined center. As a result, the low became Tropical Storm Bret at this time, while situated about 185 mi (300 km) east-southeast of Trinidad. The NHC began advisories on Bret three hours later. Upon its formation, Bret became the earliest named storm on record in the Atlantic basin's main development region. Also upon developing, the cyclone attained its minimum barometric pressure of . Bret moved swiftly westward towards Trinidad and Tobago at speeds of nearly , an unusually fast pace for a tropical cyclone, especially at such a low latitude. The storm was not expected to intensify significantly or last long due to increasing vertical wind shear and land interaction with Venezuela.
Early on June 20, a small central dense overcast formed near the center of Bret while satellite presentation improved. At 02:00 UTC, the system made landfall in southwestern Trinidad with winds of 50 mph (85 km/h), the storm's maximum sustained wind speed. After crossing the island, Bret emerged into the Gulf of Paria, before making another landfall on the Paria Peninsula of Venezuela at 09:00 UTC on June 20 at the same intensity. The effects of the hostile environment the cyclone was entering soon began to take its toll on the system, with the cloud pattern of the system becoming elongated. By 12:00 UTC, Bret was no longer a tropical cyclone as the circulation had dissipated. Operationally, the NHC continued advisories until 21:00 UTC, with the system located near Bonaire. Regeneration was not expected, but after crossing Central America and entering the eastern Pacific, the remnants of Bret contributed to the development of Hurricane Dora on June 26.