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© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Between 14 and 16 June 2023, an extratropical cyclone affected the south-southeastern coast of Brazil, causing significant damage and loss of life. In the state of Rio Grande do Sul, Civil Defense authorities reported at least 16 fatalities. Although numerical models can simulate the general characteristics of extratropical cyclones, they often struggle to accurately represent the intensity and timing of strong winds and heavy precipitation. One approach to improving such simulations is the use of convective-permitting models (CPMs), in which convection is explicitly resolved. In this context, the main objective of this study is to assess the performance of the Weather Research and Forecasting (WRF) model in CP mode, nested in the ERA5 reanalysis, in representing both the synoptic and mesoscale structures of the cyclone, as well as its associated strong winds and precipitation. The WRF-CP successfully simulated the cyclone’s track, though with some discrepancies in the cyclone location during the first 12 h. Comparisons with radar-based precipitation estimates indicated that the WRF-CP captured the location of the observed precipitation bands. During the cyclone’s occlusion phase—when precipitation was particularly intense—hourly simulated precipitation and 10 m wind (speed, zonal, and meridional components) were evaluated against observations from meteorological stations. WRF-CP demonstrated strong skill in simulating both the timing and intensity of precipitation, with correlation coefficients exceeding 0.4 and biases below 0.5 mm h−1. Some limitations were observed in the simulation of 10 m wind speed, which tended to be overestimated. However, the model performed well in simulating the wind components, particularly the zonal component, as indicated by predominantly high correlation values (most above 0.4), suggesting a good representation of wind direction, which is a function of the zonal and meridional components. Overall, the simulation highlights the potential of WRF-CP for studying extreme weather events, including the small-scale structures embedded within synoptic-scale cyclones responsible for producing adverse weather.

Details

Title
Convection-Permitting Ability in Simulating an Extratropical Cyclone Case over Southeastern South America
Author
Magalhães Matheus Henrique de Oliveira Araújo 1 ; Reboita, Michelle Simões 2 ; da Rocha Rosmeri Porfírio 1   VIAFID ORCID Logo  ; Baldoni Thales Chile 2   VIAFID ORCID Logo  ; Gomes, Geraldo Deniro 1   VIAFID ORCID Logo  ; Mattos Enrique Vieira 2   VIAFID ORCID Logo 

 Departamento de Ciências Atmosféricas, Universidade de São Paulo (USP), Rua do Matão 1226, São Paulo 05508-090, SP, Brazil; [email protected] (M.H.d.O.A.M.); [email protected] (R.P.d.R.); [email protected] (G.D.G.) 
 Instituto de Recursos Naturais, Universidade Federal de Itajubá (UNIFEI), Av. BPS, 1303, Itajubá 37500-903, MG, Brazil; [email protected] (T.C.B.); [email protected] (E.V.M.) 
First page
675
Publication year
2025
Publication date
2025
Publisher
MDPI AG
e-ISSN
20734433
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3223875504
Copyright
© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.