The February 2021 Great Plains cold air outbreak (CAO) was a high-impact weather event involving numerous power outages, traffic incidents, widespread winter storm warnings, and various cold-related fatalities (BBC News, 2021;NWS, 2021a). Texas was impacted particularly hard due to the failures of power generation, natural gas supply, and water infrastructure (Doss-Goslin et al., 2021). Based on certain metrics, this event was the second most severe Great Plains CAO since 1950(Millin et al., 2022. Given the high degree of severity, there is great importance in understanding potential sources of atmospheric predictability in both observations and models that could improve forecasts of such events on the subseasonal-to-seasonal (S2S) timescale (i.e., 2-8 weeks; e.g., Vitart & Robertson, 2018).The stratospheric polar vortex, which is the boreal wintertime cyclonic circulation 10-50 km high in the atmosphere near the North Pole, has links to Northern Hemisphere CAO development. If vertically propagating planetary-scale waves break in the stratosphere, the stratospheric polar vortex will weaken and warm; if the westerly circulation reverses then a major sudden stratospheric warming occurs (