Historical and future mid-latitude storm changes in climate models

Mid-latitude storms play a vital role in setting the climate and weather, including extreme events, in the extratropics. Given the impact of the storms on both synoptic and multi-decadal timescales, it is important to assess the representation of the storms in climate models, as the models are one of the main tools for examining historical and future human-induced climate changes. Storm tracks describe the regions where synoptic mid-latitude storms are prevalent, and the nature of storms within the storm tracks can be characterized either from the viewpoint of storm statistics at a fixed point in space (Eulerian perspective) or from the viewpoint of the properties of individual storms as they move in space (Lagrangian perspective). From an Eulerian perspective, while climate models are found to reproduce historical summer storm track changes adequately, they hold biases in representing the winter storm tracks in recent decades. Moreover, the lack of a thorough analysis of historical changes in the Lagrangian properties of the storms prevents one from assessing our confidence in mid-latitude model projections. Lastly, another important challenge that needs to be tackled is the relatively large spread across climate models in storm projections.