Holder et al. (2026) Enhanced Occurrence of Springtime Extreme Precipitation Associated With Mesoscale Convective Systems Over the US by Baroclinic Annular Mode

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Geophysical Research Letters
• Year: 2026
• Date: 2026-08-25
• Authors: Zachary Holder, Yanjun Hu, Wenfang Lei, Daniel R. Chavas, Zhe Feng, Lai-Yung Ruby Leung
• DOI: 10.1029/2025gl120614

Research Groups

• Department of Atmospheric Science, University of Colorado Boulder
• National Center for Atmospheric Research (NCAR)

Short Summary

This study investigates the influence of natural climate variability on mesoscale convective systems (MCSs) and their contribution to extreme precipitation in the United States. The research reveals that MCSs are nearly twice as likely to produce extreme precipitation during the intense positive phase of the Baroclinic Annular Mode (BAM).

Objective

• Investigate the relationship between natural climate variability, particularly the Baroclinic Annular Mode (BAM), and the occurrence of extreme precipitation from mesoscale convective systems (MCSs)

Study Configuration

• Spatial Scale: Continental-scale analysis over the United States
• Temporal Scale: Seasonal analysis during springtime

Methodology and Data

• Models used: Not specified in the abstract, but likely involved numerical weather prediction models to simulate MCSs and ETC trajectories.
• Data sources: Satellite observations, reanalysis datasets (e.g., ERA5), and/or surface weather station data

Main Results

• The occurrence of extreme precipitation from MCSs nearly doubles during the intense positive phase of BAM.
• Positive phase of BAM slows down zonal translation speed of extratropical cyclone (ETC) trajectories, creating a favorable dynamical environment for extreme MCS precipitation.
• When ETCs and MCSs coincide, they account for more than 90% of extreme precipitation during springtime in the U.S.

Contributions

• This study provides new insights into the multiscale interactions between planetary-scale climate variability (BAM), synoptic-scale extratropical cyclones, and mesoscale convective systems.
• The findings highlight the significant regional impacts of these interactions on extreme precipitation events.

Funding

• Not specified in the abstract.

Citation

@article{Holder2026Enhanced,
  author = {Holder, Zachary and Hu, Yanjun and Lei, Wenfang and Chavas, Daniel R. and Feng, Zhe and Leung, Lai-Yung Ruby},
  title = {Enhanced Occurrence of Springtime Extreme Precipitation Associated With Mesoscale Convective Systems Over the US by Baroclinic Annular Mode},
  journal = {Geophysical Research Letters},
  year = {2026},
  doi = {10.1029/2025gl120614},
  url = {https://doi.org/10.1029/2025gl120614}
}