Robust Relationship Between Midlatitudes CAPE and Moist Static Energy Surplus in Present and Future Simulations

Abstract

Abstract Convective available potential energy (CAPE), a metric associated with severe weather, is expected to increase with warming, but we have lacked a framework that describes its changes in the populated midlatitudes. In the tropics, theory suggests mean CAPE should rise following the Clausius–Clapeyron (C–C) relationship at ∼6%/K. In the heterogeneous midlatitudes, where the mean change is less relevant, we show that CAPE changes are larger and can be well‐described by a simple framework based on moist static energy surplus, which is robust across climate states. This effect is highly general and holds across both high‐resolution nudged regional simulations and free‐running global climate models. The simplicity of this framework means that complex distributional changes in future CAPE can be well‐captured by a simple scaling of present‐day data using only three parameters.

Keywords

• CAPE
• climate change
• atmospheric convection
• high‐resolution models
• CMIP6