| Abstract | An African easterly wave and associated MCSs dataset has been created and used to evaluate the propagation of MCSs, AEWs, and especially, the propagation of MCSs relative to the AEW they are associated with (i.e., wave-relative framework). The thermodynamic characteristics of AEW-MCS systems are also analyzed. The analysis is done for both AEW-MCS systems that develop into at least a tropical depression and those that do not to quantify significant differences between waves that undergo tropical cyclogenesis (DAEW) and those that do not (NDAEW). It is shown that DAEWs over West Africa are associated with a larger number of CCC-type convection (squall lines) than NDAEWs and that these convective systems propagate at the same speed of the AEW trough, whereas convection associated with NDAEWs over West Africa moves faster than the trough. These results become important for the intensification of the AEW vortex as this slower-moving convection, i.e. moving at the same speed of the AEW trough, spends more time supplying moisture and latent heat to the AEW vortex supporting its further intensification. An analysis of the rainfall rate (MCS intensity), MCS area and latent heat rate contribution reveals that there are statistically significant differences between these two wave groups, specifically over West Africa where the fraction of extremely large MCS areas associated with DAEWs is larger than for NDAEWs. A variance decomposition analysis indicates that the contribution of MCS area variability to the latent heat rate variance of AEW-MCS systems is larger than that from rain rate variance. |
