In the fourth week of September, a very large tropical wave emerged off the coast of Africa and tracked south of Cape Verde. It slowly became organized, by early on September 25, it became a tropical depression, and 6 hours later was upgraded to Tropical Storm Karen. It was slow to become stronger at first, but on September 26, Karen quickly became stronger and was made a hurricane early in the day before added wind shear stopped the intensification and began to slowly weaken the storm. Karen was declared to have been at hurricane strength by the NHC on November 27, 2007.