Potential Use of Stratospheric Meridional Mass Circulation Signals in the Sub-Seasonal Forecasts of Continental-Scale Cold Events in NH Winter

Sub-seasonal prediction is the central component but the key bottleneck of the seamless forecasting. Exploring more predictability sources and improving the prediction skills at sub-seasonal range can increase our chance to plan ahead and devise an optimal strategy to minimize the adverse impacts of weather disasters on the socioeconomic wellbeing of the modern society. A new predictor for continental-scale cold events in the mid-latitudes, the pulse signals in the stratospheric meridional mass circulation (PULSE), is introduced in this paper. The PULSE event has sub-seasonal predictability, close physical linkage with the temporal-spatial variations of surface air temperature in mid-latitudes, and can be derived from model forecast output directly. Therefore, the PULSEs are used to build a hybrid (dynamical-statistical) paradigm for sub-seasonal forecasts of continental-scale cold events in the mid-latitudes.