Evaluation of the Canadian Regional Climate Model in Simulating Extratropical Cyclones Over Northeastern North America

Abstract The ability of convection‐permitting regional climate models to realistically simulate extratropical cyclones (ETCs) and associated near‐surface wind speeds and precipitation remains poorly documented. This study provides the first comprehensive evaluation of the sixth version of the Canadian regional climate model (CRCM) for this purpose over northeastern North America. Two CRCM configurations are assessed: a ∼12‐km horizontal grid‐spacing configuration with parameterized deep convection, driven by the ERA5 reanalysis, and a ∼2.5‐km grid‐spacing configuration with explicit convection, nested in the 12‐km simulation. Using an ETC tracking algorithm, ETC storm activity, including the intensity and lifetime, are evaluated against ERA5 over northeastern North America. Simulated ETC‐associated hourly near‐surface wind speeds and precipitation are compared with in situ stations (ISD), satellite (IMERG), and radar (StageIV) observations over a common northeastern United States region. The 12‐km simulation reproduces cyclone tracks and lifetimes comparable to ERA5, whereas the 2.5‐km version generates more and longer‐lasting storms. Both configurations capture the main characteristics of ETC‐associated surface fields, but the 2.5‐km model better represents extreme precipitation rates and reduces wind speed biases. Decomposing the errors in wind and precipitation fields reveals that discrepancies are dominated by biases in the average wind and precipitation associated with ETC events, while errors in storm occurrence play a secondary role. Overall, both configurations reasonably reproduce ETC characteristics, but the convection‐permitting 2.5‐km version is better suited for local‐scale climate analyses.