Climatological features of future mesoscale convective systems in convection‐permitting climate models using CMIP6 and ERA5 in the central United States

Abstract

Motivated by the limited understanding of future changes in Mesoscale Convective Systems (MCSs), we investigated characteristics of warm‐season (June‐August) MCSs in the central United States based on high‐resolution convection‐permitting Weather Research and Forecasting (WRF) simulations. We examined two 15‐year simulations, which include current simulations (2004‐2018) forced by ECMWF reanalysis version 5 (ERA5) and future simulations (2086‐2100) forced by perturbed ERA5 (i.e., ERA5 + climate change signal derived from 28 Coupled Intercomparison Projected Phase 6 models under the Shared Socioeconomic Pathway‐Representative Concentration Pathway 8.5 emission scenario). The initiations and longevities of MCSs were determined using the object tracking algorithm MODE‐Time Domain (MTD) from observation (OBS), current simulations (ERA), and future simulations (PGW). MTD‐identified objects were divided into short‐/long‐lived (based on 75th percentiles of longevity) and daytime (initiated during 00‐11 UTC)/nighttime (initiated during 12‐23 UTC). We found that ERA and OBS have comparable occurrences of MCSs. MCSs in PGW are associated with intensified rain rates (RR) in New Mexico, Colorado, and Kansas and lower RR in Texas, Louisiana, and Arkansas than in ERA. Moreover, the statistical analysis based on 15 parameters before MCSs initiation indicates that short‐lived MCSs in PGW are characterized by prominent changes in precipitable water (PW) and the most unstable convective available potential energy (MUCAPE). We also found that long‐lived MCSs in PGW are associated with prominent changes in PW, MUCAPE, and isentropic potential vorticity at 345K. According to the statistical results, PW is the most important variable in determining the longevity of MCSs and in understanding future changes.This article is protected by copyright. All rights reserved.