Tropical Storm Kirk was the second lowest-latitude tropical storm on record in the Atlantic basin. The eleventh named storm of the 2018 Atlantic hurricane season, Kirk originated from a tropical wave that left Africa on September 20 and organized into a tropical depression two days later. The system intensified into Tropical Storm Kirk early on September 22 but quickly degenerated into a tropical wave again early the next day. A reduction in the disturbance's forward speed allowed it to regain tropical storm intensity on September 26. Kirk reached maximum sustained winds of that morning before increasing westerly wind shear caused the cyclone to steadily weaken. The storm made landfall on Saint Lucia with winds of before continuing into the Caribbean Sea. Kirk degenerated to a tropical wave again on September 28, and its remnants continued westward, contributing to the formation of Hurricane Michael ten days later.
Kirk passed narrowly north of Barbados, where tropical storm-force winds cut power to multiple neighborhoods and caused property damage at the official residence of the Governor-General. Rainfall in excess of flooded structures and vehicles, prompting 11 emergency water rescues. In Saint Vincent and the Grenadines, rough seas caused coastal flooding and led to the presumed deaths of two fishermen after they ventured out during the storm. On Saint Lucia, strong winds destroyed two buildings; additional structures, including schools and the anemometer at the Hewanorra International Airport, sustained damage. About 2,000 chickens on a poultry farm were killed following the collapse of their pens, and about 80–90% of the island's banana crop was left in ruin. The combination of winds and landslides prompted widespread power outages. Lesser impacts were felt on Martinique, where winds damaged trees and cut power to about 3,000 homes.
Meteorological history
A low-latitude tropical wave departed the western coast of Africa late on September 20 and moved rapidly west-northwest. After two days of sporadic convective development, it acquired sufficient organization to be declared a tropical depression by the National Hurricane Center (NHC) around 06:00 UTC on September 22 to the south of Cabo Verde. Six hours later, the depression intensified into Tropical Storm Kirk at 8.1°N, representing the second lowest-latitude tropical storm on record in the Atlantic; only the third storm of the 1902 hurricane season formed farther south. A subtropical ridge to the north of the newly formed cyclone expanded westward, directing the system in the same direction. Kirk became less organized over the next day as a large band of convection, similar to an outflow boundary, propagated away from the center into the northwestern quadrant. This cloud pattern suggested the entrainment of mid-level dry air. The hostile environment caused Kirk to degenerate into a tropical wave by 12:00 UTC on September 23. Even after degeneration, the storm's remnants continued to produce a large area of showers and thunderstorms, along with gale-force winds in the northern quadrant.
By September 26, the forward motion of the remnants slowed, allowing convection to coalesce about a new well-defined center. The NHC accordingly re-initiated Kirk as a tropical storm around 00:00 UTC on September 26 about 520 miles (835 km) east-southeast of Barbados. By the morning hours, Kirk's presentation had evolved to feature a strong central dense overcast with few banding features. Satellite intensity estimates were used to assign a peak intensity of at 12:00 UTC through 18:00 UTC on September 26. Thereafter, the cyclone's presentation morphed into a comma-shaped appearance, with the center at times partially exposed on the western edge of this convection due to increasing westerly wind shear. Kirk temporarily moved west-northwest, passing just north of Barbados, before banking west-southwest under the dominant steering regime of a ridge in the western Atlantic. It struck Saint Lucia as a tropical storm around 00:30 UTC on September 30 and entered the Caribbean, where the storm resumed a west-northwest course while continuing to lose strength. By 00:00 UTC on September 29, after a reconnaissance aircraft was unable to locate a well-defined and closed center, the NHC downgraded Kirk to a tropical wave again while it was positioned a few hundred miles south of the United States Virgin Islands. The remnants continued into the western Caribbean, where they were absorbed by a large area of disturbed weather by October 2 and contributed to the formation of Hurricane Michael.