4.3 African Easterly Wave–Mesoscale Convective Coupled Systems That Are Potential Candidates for Tropical Cyclogenesis

Monday, 7 January 2019: 3:30 PM
North 232AB (Phoenix Convention Center - West and North Buildings)
Kelly Marie Nunez Ocasio, The Pennsylvania State Univ., Univ. Park,, PA; and J. L. Evans

Handout (2.7 MB)

Over Tropical Africa, Mesoscale Convective Systems (MCSs) move with African Easterly Waves (AEWs) as a coupled system. Although studies have shown that the interaction of MCSs with AEWs can potentially aid in the growth of the AEWs, and consequently contribute to tropical cyclogenesis, how the coupled system evolves remains an open question. We will present analyses testing the hypothesis that the MCSs embedded in an AEW over its lifecycle can provide the necessary environmental vorticity for TCs to form. To test this hypothesis, the first step is the development of Tracking Algorithm for Mesoscale Convective Systems (TAMS), an algorithm that documents the lifecycle evolution of the characteristics of MCSs over Africa. TAMS combines area-overlapping and projected-cloud-edge system tracking techniques to maximize the probability of detecting the progression of an anvil cloud through time, while accounting for splits and mergers. Sensitivity tests are used to determine the propagation speed for organized MCS over Africa. MCS lifecycles derived using TAMS are consistent with climatology. Further, TAMS can be used to identify and characterize MCS propagation within and AEW to deduce whether or not MCSs embedded in a developing AEW (i.e. an AEW associated with tropical cyclogenesis) are more likely to move with, behind, or ahead, of the AEW compared to MCSs in non-developing AEWs.
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