on august 23, a tropical wave emerged into the atlantic from the west coast of africa. shortly after entering the atlantic, the tropical wave developed into a low-pressure area. over the next few days, the cloud pattern associated with the system fluctuated in organization and a tropical depression may have developed as early as august 24. two days later, satellite imagery indicated a well-defined low-level cloud center. as a result, it is estimated that tropical depression twelve developed at 12:00 utc on august 26. the depression slowly intensified as it tracked west-northwestward under the influence of low- to mid-level flow. although sea surface temperatures were warm, outflow from hurricane humberto may have slowed further strengthening of the depression.