Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

Projections of Australian low pressure systems in downscaled CMIP6 models

Acacia Pepler , Giovanni Di Virgilio, Andrew Dowdy, Rishav Goyal, Chun-Hsu Su , Marcus Thatcher, Jozef Syktus

Abstract

Low pressure systems are associated with a number of climate hazards in Australia, including heavy rainfall, strong winds, and coastal erosion. Here we use a new ensemble of 40 CMIP6-based regional model projections to assess future changes in low pressure systems across Australia, with a focus on vertically developed (deep) cyclones which extend between the surface and 500hPa. Results show robust future declines in extratropical lows in southern Australia throughout the year, with large uncertainty for lows in northern Australia. Projections for strong, rapidly-intensifying, and slow-moving low pressure systems are also assessed, and are all projected to decline in frequency. The strongest declines in lows are identified for models that also have larger increases in the intensity of 500hPa zonal winds to the south of Australia (40-50°S), with observed trends in both indices at the high end of the model range. This suggests the potential for constraining future projections of Australian low pressure systems based on monthly mean zonal winds.

ES25025  Accepted 03 September 2025

© CSIRO 2025