Although tropical storm-force winds did not impact the islands, the storm brought damagingly heavy rainfall to Trinidad and to St. Vincent and the Grenadines, causing two deaths on Bequia due to a mudslide.

For a late-season tropical wave, the system maintained an unusually high amount of convection as it trekked across the Atlantic Ocean.

[1] The National Hurricane Center (NHC) began to actively track the wave on November 13, when it was located about 100 mi (160 km) off the coast of Barbados.

[2] That day, a low-pressure area formed along the axis of the wave, with moderate easterly wind shear initially keeping convection displaced well to the east.

[4] Consequently, Tropical Depression Twenty-Seven developed at 00:00 UTC over the far eastern Caribbean Sea about 55 mi (90 km) west of Saint Vincent.

[1] An upper-level trough near the Greater Antilles continued to provide westerly shear that briefly stalled further development,[4][5] but the system's strong convection persisted.

[1] A deep-layered subtropical high pressure ridge over the southwestern Atlantic Ocean and Gulf of Mexico propelled the system westward across the Caribbean at more than 25 mph (40 km/h) and the storm's upper circulation was entirely separated from its deep convection and low level circulatory center.

[1] The deep-layered subtropical high pressure ridge initially caused the remnants of the tropical cyclone to continue generally westward at 23–25 mph (37–40 km/h), until the system slowed down while approaching Honduras on November 17.

However, constant rainfall for well over a day as Gamma wandered offshore caused floods that forced over 30,000 people to abandon their homes for state-run shelters.

[20][21] Two people were killed by a mudslide in St. Vincent and the Grenadines on the island of Bequia as Gamma's precursor, Tropical Depression Twenty-Seven, brought heavy rains.

[28] The rainfall triggered flooding and landslides in the northern departments of Gracias a Dios, Colón, Atlántida, Cortés, Yoro, Santa Bárbara, and the Bay Islands which killed 34 people and left 13 missing.

Heavy rains in the upstream watersheds of the Paulaya and Sico rivers caused widespread inundation across downstream communities.

[32] After the storm turned out to sea and Gamma's rains desisted, Honduran helicopters began rescuing those stranded by flood waters.

[32] Both of these organizations already had active distribution networks in the country as they were responding to hurricanes Stan, Wilma, and Beta, all of which caused fatalities in Honduras that year.

[36] Gamma's record-setting formation date as the season's 25th tropical or subtropical storm would stand until 2020, when broken by Hurricane Delta, which formed on October 5.