harmclan wrote:Dennis originated from an Inverted V wave.
The genesis Katrina was influenced by mid-latitude and tropical interactions. The precursor to Hurricane Katrina could be traced to convection along the tail-end of a mid-latitude trough on 14 August. That convection drifted south and then northwestward. Between 17 and 18 August, evidence of a vortex northeast of Puerto Rico could be seen in water vapor image. That upper-level vortex drifted northwestward and then southwestward towards the eastern Bahamas over the next three days. During the same period, a second cyclonic circulation centered at 500hPa over Hispaniola produced several MCSs. A tropical wave entered the eastern Caribbean but weakened as it moved westward. By 21 August, convection over the Caribbean was primarily associated with the mid-level circulation over Hispaniola. Between 22 and 23 August, the northern upper-level circulation merged with the strengthening mid-level circulation. Convection intensified around was now a tropical depression. An interesting feature of the period of intensification was very dry middle-level air mixing into to the west and north of the tropical depression.
Thanks Harmclan!
