The rainy season of the north portion of Northeast of Brazil (NEB) occurs between February and May due to the southward displacement of the Intertropical Convergence Zone (ITCZ). During that period, a large number of mesoscale convective systems form in that region, under the dynamical influence of the large-scale convergence.
As it can be observed, several systems form near the Ibiapaba mountain range, which is located in the northwest region of Ceará state, north portion of NEB. These systems commonly form during the afternoon and move westward producing, many times, a significant amount of precipitation. They contribute for a bigger total rainfall in this region, compared to other locations of NEB.
In this work, we analyze cases of the formation of these systems, during the year of 1994, for which the precipitation in Northeast Brazil was close to the average. We evaluate the relative importance of large-scale forcing and local effects such as topography and land-sea differential heating to the formation of Ibiapaba convective systems, using the capabilities of a limited-area model.