The Role of Wave Breaking in the Development and Subseasonal Forecasts of the February 2021 Great Plains Cold Air Outbreak

The February 2021 cold air outbreak (CAO) was a high-impact event in the South-Central Plains of United States. This study examines important precursors to that likely impacted its predictability subseasonal forecasts. We use reanalysis show CAO facilitated by two distinct wave breaks—an East Siberian Sea anticyclonic break and Labrador cyclonic break. also European Center for Medium-Range Weather Forecasts National Environmental Prediction subseasonal-to-seasonal models investigate impact breaks on forecast skill at ?2–3 weeks lead time. Ensemble members successfully simulating these features produce more negative temperature anomalies across Great Plains, corresponding better positioning anomalous ridging. These results demonstrate persistent anticyclones can improve central US extreme forecasts long leads.