The extratropical atmospheric circulation is characterized by large-scale variability patterns such as blocking events, large-amplitude/quasi-stationary planetary waves, stratospheric polar vortices, and annular modes. The midlatitude variability is important to the extratropical weather (and weather extremes), as well as the interaction of the extratropical troposphere with the tropics, stratosphere, ocean, and cryosphere. While widely studied, many questions remain unanswered about the dynamics, predictability, and climate projections of the extratropical atmospheric variability, and current weather/climate models have difficulties faithfully reproducing some of the observed behavior.

The goal of this session is to synthesize observational, idealized-to-comprehensive hierarchical modeling (including model intercomparisons), empirical (e.g. data science/machine learning) and theoretical studies of various aspects of this variability such as the associated dynamics, sources of predictability, responses to climate change, and connections with weather extremes. A deeper understanding will improve weather predictions on sub-seasonal and longer timescales, and help with interpreting regional responses to climate change.