Skip to main content
U.S. flag

An official website of the United States government

Publication Date
1 April 2023

Subseasonal Representation and Predictability of North American Weather Regimes

Print / PDF
Powerpoint Slide
Science

We use unsupervised learning (k-means clustering), ERA5 reanalysis, and the CESM2 subseasonal initialized prediction system (with 11 ensemble members) to assess the sources and limits of predictability of North American weather regimes.

Impact

Weather regimes help describe large amplitude flow patterns within lower temporal frequencies, which extend beyond the lifetime of individual weather disturbances. Weather regimes also have an imprint on weather at the surface, with certain regimes providing favorable large-scale environmental conditions for notable temperature and precipitation anomalies, along with impacts to storm tracks, moisture flux, and atmospheric rivers.

Summary

North American weather regimes are large-scale atmospheric patterns that can persist for several days. Their skillful subseasonal prediction can provide valuable lead time to prepare for temperature and precipitation anomalies that can stress energy and water resources. The purpose of this study was to assess the climatological representation and subseasonal predictability of North American weather regimes. We found that the Pacific trough and West Coast high regimes exhibited higher predictability and that skillful representation of conditions across the tropics and extratropics can increase predictability during later lead times.

Point of Contact
Maria J. Molina
Institution(s)
University of Maryland - College Park
National Center for Atmospheric Research (NCAR)
Funding Program Area(s)
Publication