High-latitude regions are undergoing rapid changes with far-reaching consequences for the global environment, weather extremes, and socioeconomic systems. Yet understanding these changes and predicting their impacts across S2D timescales remains a central challenge in Earth system science and modeling. This session aims to integrate progress in three key areas of S2D research: observational records and reanalysis products that enhance understanding of and constrain high-latitude variability, dynamical models that reproduce critical processes and complex atmosphere-ocean-sea ice-land interactions, and AI and machine learning techniques that assist with analyses, bias correction, parameterizations, and emulations. We invite contributions that advance understanding and address sources and limits of HLES predictability, spanning scales from process-level dynamics to complex system interactions. Topics of interest include snow and ice cover, upper-ocean thermo-dynamics and biogeochemistry, land hydrology, air-sea-land interactions, polar vortex dynamics, extreme events, and teleconnections to lower latitudes.

• A - Atmospheric Sciences
• B - Biogeosciences
• C - Cryosphere
• OS - Ocean Sciences