National Hurricane Center
On September 12, satellite images indicated that the eighteenth tropical depression of the season formed southwest of Cabo San Lucas. Located in close proximity to Tropical Storm Norbert, the depression would soon enter a region of colder sea surface temperatures, and the National Hurricane Center noted that only very little intensification was possible. As predicted, Norbert hindered further intensification of Tropical Depression Eighteen-E. The National Hurricane Center noted six hours later that the depression would likely be absorbed into Norbert. The National Hurricane Center later believed that Tropical Depression Eighteen-E was "dominating" the interaction between the two systems, and was forecast to absorb Norbert. Unlike the latter prediction, Norbert absorbed Tropical Depression Eighteen-E later that day.