Favorable circulation patterns and moisture sources for wintertime extreme precipitation events over the Balkhash-Junggar region

This Rossby wave train deepens a cyclonic anomaly in the lower troposphere over the B-J region, which favors the development of strong southwesterly moisture transport and strong updrafts there. These conditions are favorable for the occurrence of extreme precipitation events over the B-J region. Lagrangian moisture source analysis indicates that most of the moisture for precipitation during these events comes from terrestrial sources, with central Asia the key moisture source region.

The Eulerian moisture budget analysis further shows that most of the moisture for extreme precipitation enters the B-J region through its western boundary via enhanced southwesterly flow. These dynamical and moisture source analyses establish a set of valuable precursor conditions for predicting wintertime extreme precipitation events over the B-J region.