Impacts of the Arctic-midlatitude teleconnection on wintertime seasonal climate forecasts

Abstract The impact of the Arctic on midlatitude weather and climate is still in scientific debate. The observation-based analysis, however, shows frequent concurrences of Arctic warming with extreme cold in the midlatitudes, and vice versa. This teleconnection could aid in seasonal climate forecasts for the midlatitudes. This study assessed the forecast skill of Arctic temperature and the Arctic-midlatitude teleconnection patterns in operational seasonal climate forecast models based on their wintertime forecast archives. Further, the impact of the Arctic-midlatitude teleconnection on the midlatitude forecast skill is evaluated. The results revealed that most climate forecast models have the capability to simulate the overall pattern of Arctic-midlatitude teleconnection for both the eastern Eurasian and North American regions. However, this is little converted to practical forecast skill in midlatitude likely due to poor capabilities in forecasting Arctic temperatures. Idealized analysis (assuming a perfect forecast of Arctic temperature) showed that considerable forecasting improvements could be achieved, and further improvements are possible with accurate simulations of the Arctic and its teleconnection patterns. These results highlight the importance of better predictions of the Arctic conditions in seasonal forecasts that are not just limited to their own region but extend to midlatitude weather and climate as well.