Predictability of a supercell using convection-permitting ensemble simulations in Argentina

ALVAREZ IMAZ, MILAGROS; SALIO, PAOLA V.; DILLON, MARIA EUGENIA; FITA, LLUIS; CARRIÓ, DIEGO SAÚL

Buenos Aires

Workshop; VI Convection-Permitting Climate Modeling Workshop; 2022

NCAR and CIMA

Sierras de Córdoba (SDC) is a mountain range located eastward to the Andes range strongly associated with theinitiation and further upscale growth of deep moist convection. The location and timing of convective initiation(CI) over this region is strongly forced by the presence of moisture availability and large scale conditions as wellas local mesoscale processes.In order to analyze the predictability of the CI over SDC, six 20-member ensembles with the WRF modelat convection-permitting resolution (3 km) were carried out to study a marginal supercell initiated at theSDC foothills. The experiments consisted of 24-h forecasts initialized on 00 UTC October 17, 2017, using 3-hfrequency boundary conditions from 2 different global ensemble forecasting systems: the ECMWF model andthe GEFS. They were built using 3 different microphysics parameterizations (WSM6, Thompson and Morrison)and 2 planetary boundary layer parameterizations (Yonsei University and Mellor Yamada Janjic). It is shownthat the forecasted environment is favorable for supercell formation with the majority of the configurations. CIover the eastward side of SDC is strongly forced by the presence of instability and moisture availability as wellas mesoscale circulations providing low level convergence. A strong easterly component of the wind, promotingthe convergence of the wind over the mountains is noticeable in all members with convection development.