Plain Language Summary
In February 2022, an extreme cold event affected the Beijing-Tianjin-Hebei (BTH) region during the Winter Olympics, posing significant challenges to public health and economic activities. This study investigates the main subseasonal atmospheric conditions that caused this extreme cold spell by observational diagnostics and subseasonal prediction analyses. Two propagating quasi-biweekly oscillations (QBWO) contributed to the development of the event by generating and enhancing a low-level cyclonic anomaly, which created favorable conditions for cold air accumulation over BTH. The fidelity of the dynamic model to the mid–high-latitude QBWO signals determines the accuracy of the subseasonal prediction of such cold events.

Extreme cold wave,subseasonal prediction,intraseasonal variability