During the last week of September, a tropical wave entered the Caribbean sea and moved westward, bringing precipitation to the Windward Islands as it passed by. A few days later, a broad low-pressure formed in association with the system over the western Caribbean. The nascent circulation received some help from a Central American gyre (CAG), a seasonal monsoonal broad low that tends to persist over the region, especially in May-June and October-November. By October 1, a large-scale swirl was evident, but there wasn't much convection near the center. However, on October 2, the system became well-defined enough to be classified Tropical Depression Twenty-Five well north of the coastline of Honduras.
The depression moved slowly northwest and strengthened into Tropical Storm Gamma that night. Gamma was only the second instance of a 24th named storm in recorded history after Beta of 2005, which was named on October 27 of that year (an unnamed subtropical storm in 2005 was the reason the 24th named storm was Beta, not Gamma). Conditions were very favorable for intensification and the system strengthened quickly as it approached the Yucatan peninsula. The next morning, Gamma was reported as reaching its peak intensity of 70 mph winds and a minimum pressure of 980 mb before making landfall in the northeastern Yucatan around noon local time.
Though the above intensity was the operational peak observed for Gamma, a more careful post-season analysis found that the storm in fact achieved category 1 hurricane status just before landfall, around 16:45 UTC October 3. The revised intensity was 75 mph winds and a pressure of 978 mb.
Land did not weaken the storm much; in particular, flooding rains continued as the center moved slowly north-northwestward. Overnight, Gamma emerged into the Gulf of Mexico. Waters were still warm, but shear increased, halting any reintensification by later on October 4. At the same tame, the trough that had been lifting the cyclone north moved on, leaving Gamma trapped under a weak developing ridge. As a result, the cyclone began meandering. Overnight, shear and dry air removed nearly all thunderstorm activity from the circulation and the storm quickly weakened. It also retreated southwest, back toward land, and weakened to a tropical depression on October 5. Soon, it became a remnant low. Before long, the low was absorbed by the approaching Hurricane Delta.
The above image shows Gamma at peak intensity on October 3, just before making landfall in the Yucatan Peninsula.
Unfavorable conditions prevented Gamma from strengthening further in the Gulf of Mexico; it instead took an unusual path and made a second landfall in the Yucatan.
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