Temporal evolution of summer convective activity over the Americas warm pools -: art. no. L02803

[ 1] The present analysis describes the temporal evolution of various meteorological parameters over the Americas warm pools that are related to the occurrence of the Mid Summer Drought ( MSD). Contrary to what has been suggested by some authors, the bimodal structure of precipitation over the Pacific side of Mesoamerica is not a form of intraseasonal variability in convective activity related to the Madden Julian Oscillation, but a characteristic of the annual cycle in precipitation. The MSD - sea surface temperature ( SST) radiation relationship proposed by Magana et al. [ 1999] partially hold during the summer of 2001, when the Climate Experiment over the Americas Warm Pools ( ECAC) field campaigns were conducted, with the SST exhibiting a bimodal structure in the MSD region. The maximum in tropical convection over the Central America- Caribbean coast appears to play an important role in modulating convective activity in the surrounding regions, through induced subsidence related to direct circulations. The Caribbean Low Level Jet ( CLLJ) is in phase with maximum western Caribbean Sea convective activity, reaching maxima intensities in July.