Changes in the Kain-Fritsch convective parameterization scheme (KF2) were included to better represent the precipitation in simulations using the MM5 regional model for the Alcântara Launch Center (CLA) region. Daily (24 h) integrations for a 30 km grid spacing domain centered in CLA were performed for 2005-2006 (calibration) and 2008 (validation). KF2 scheme was modified under the following simulation settings: time step of 60 s, use of warm rain scheme and joint use of Grell and KF2 shallow convection schemes. Changes in KF2 were: increase of minimum cloud depth to initiate deep convection and several trigger function parameters dependent on column upward vertical motion. With the changes, marked improvement in the representation of total precipitation and monthly fraction of rainy days was found. The spatial pattern of errors over the domain, however, did not show substantial changes (in general, precipitation was better represented over land than over ocean). The steps carried out in this work to change KF2 could be followed to improve the precipitation representation over other specific regions.
quantitative precipitation forecast; deep convection; northern coast of Brazil; Maranhão State
