The relationship between teleconnections, surface temperature, and cold air outbreaks

Cold air outbreaks (CAOs) are extreme events that can negatively impact the agricultural industry, human health, and cause widespread power outages from increased energy consumption. Increasing the predictability of CAOs is critical to limiting the adverse impacts on society, but skilful predictions rely on well-defined mechanisms of causation. To improve the understanding of CAO mechanisms, this study examines the relationship between atmospheric and oceanic teleconnection indices and CAOs in the Northern Hemisphere (NH) during two distinct periods, 1979-1998 and 1999-2018. Changes in the relationship between CAOs and teleconnections during these two periods are calculated and used to determine the teleconnections that currently have the strongest relationship with CAOs across the NH. Several relationships were found to no longer be significant while several other significant relationships have emerged, particularly with the Tropical Northern Hemisphere (TNH) pattern. Furthermore, upstream teleconnections, as opposed to downstream teleconnections, were generally found to have a stronger relationship with CAOs. The East Pacific Oscillation and East Pacific/North Pacific pattern were found to have the strongest relationship with CAOs in the eastern U.S. and Alaska, while the Arctic Oscillation, North Atlantic Oscillation, Greenland Blocking Index, and Scandinavian pattern have the strongest relationship with CAOs in Eurasia.