A provisional climatology of the mesoscale convective systems in the Yucatan Peninsula in summer

Abstract

Principal characteristics of summer mesoscale convective systems in the Yucatan Peninsula, Mexico, were studied using three years of radar imagery. MCSs occurred almost daily in this region, having a minimum monthly during July and August, coinciding with the Midsummer Drought. MCS movements were mostly from E, NE, and SE directions, with a mean propagation speed of 6.0 ms−1. They had a mean duration of 6.4 h, with initiation time around the afternoon and dissipation time around midnight. The most crucial synoptic forcing that influenced MCSs formation in this region was the trough, precisely a local type called Mayan trough, followed by tropical waves and unclassifiable synoptic. Inactive periods of MCSs formation related to a Caribbean low-level jet stronger than average. The organization of MCSs convection showed that half of them had a linear pattern with an N-S orientation of convective lines, and their organization was normal or parallel to the MCS orientation. Mesoscale phenomena like sea breezes significantly influence the formation of MCSs in this region.