Winter Storm Activity across Canada at the End of the Century: A CMIP5 Multi-model Projection

Abstract

Extratropical cyclones are the main source of precipitation in most of Canada. They bring hazardous weather events like blizzards, heavy snow, freezing rain, etc. They also supply fresh water through spring snow melt and maintain the soil and surface water balance in sub-humid and semi-arid regions. Any future changes in extratropical cyclone activity over Canada may have a significant impact on agriculture and the local economies of the various regions. Future changes in regional storm activity over Canada have not been studied in detail. Therefore, we examined potential changes in extratropical storm activity by the end of the century using data from six models from CMIP5 under historical and future (RCP 8.5) emission scenarios. A statistical analysis of selected storm activity indices, using a storm identification and tracking algorithm, revealed a decrease in the number of storms over the mid-latitude regions of Canada. However, intense storms with a longer duration are projected over all regions at the end of the century. A further investigation of the physical mechanisms revealed that a decrease in the meridional temperature gradient over the mid-latitude regions and shifting of the vertical wind shear are responsible for these expected changes in storm activity.