the depression finally began to develop bands north of the center on august 27, though overall, the deep convection remained disorganized; the circulation of the depression also became elongated. around 06:00 utc on august 28, the depression strengthened into tropical storm karen. early on the following day, karen peaked with maximum sustained winds of 50 mph (85 km/h). by august 31, karen north-northwestward around the circulation of hurricane iris and thus, a fujiwhara interaction began. as the storm was approaching iris, the national hurricane center (nhc) began predicting on september 1 that karen would merge with the former. on the following day, karen weakened to a tropical depression. early on september 3, karen lost its well-defined center and merged with iris at 06:00 utc, while centered near bermuda.