Abstract
This study simulates an unusual extreme rainfall event that occurred in Salvador
City, Bahia, Brazil, on December 9, 2017, which was named subtropical storm Guará and had
precipitation of approximately 24 mm within less than 1 h. Numerical simulations were
conducted using the Weather Research and Forecasting (WRF) model over three domains with
horizontal resolutions of 9, 3, and 1 km. Different combinations of seven microphysics, three
cumulus, and three planetary boundary layer schemes were evaluated based on their ability to
simulate the hourly precipitation during this rainfall event. Statistical indices (MB = -0.69;
RMSE = 4.11; MAGE = 1.74; r = 0.55; IOA = 0.66, FAC2 = 0.58) and 47 time series plots showed
that the most suitable configuration for this weather event were Mellor-Yamada-Janjić, Grell-
Freitas, and Lin for the planetary boundary layer, cumulus, and microphysics schemes,
respectively. The results were compared with the data measured at meteorological stations
located in Salvador City. The WRF model simulated well the arrival and occurrence of this
extreme weather event in a tropical and coastal region, considering that the region already has
intense convective characteristics and is constantly influenced by sea breezes, which could
interfere in the model results and compromise the performance of the simulations.