loading page

East Asian Monsoon Forcing and North Atlantic Subtropical High Modulation of Summer Great Plains Low-level Jet
  • Kelsey Malloy,
  • Ben P. Kirtman
Kelsey Malloy
Department of Applied Physics and Applied Mathematics, Columbia University

Corresponding Author:[email protected]

Author Profile
Ben P. Kirtman
University of Miami
Author Profile


Dynamic influences on summertime seasonal United States rainfall variability are not well understood. A major cause of moisture transport is the Great Plains low-level jet (LLJ). Using observations and a dry atmospheric general circulation model, this study explored the distinct and combined impacts of two prominent atmospheric teleconnections - the East Asian monsoon (EAM) and North Atlantic subtropical high (NASH) - on the Great Plains LLJ in the summer. Separately, a strong EAM and strong western NASH are linked to a strengthened LLJ and positive rainfall anomalies in the Plains/ Midwest. Overall, NASH variability is more important for considering the LLJ impacts, but strong EAM events amplify western NASH-related Great Plains LLJ strengthening and associated rainfall signals. This occurs when the EAM-forced Rossby wave pattern over North America constructively interferes with low-level wind field, providing upper-level support for the LLJ and increasing mid- to upper-level divergence.