Wu et al. (2026) How Terrain Geometry and Environmental Instability Shape Precipitation in Mountain‐Crossing Mesoscale Convective Systems

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

Identification

• Journal: Journal of Geophysical Research Atmospheres
• Year: 2026
• Date: 2026-10-01
• Authors: Fan Wu, Kelly A. Lombardo
• DOI: 10.1029/2026jd046393

Research Groups

• Department of Atmospheric Science, University of Colorado Boulder
• Laboratory for Atmosphere and Space Physics, University of Colorado Boulder

Short Summary

This study examines how terrain geometry and environmental instability modulate precipitation produced by a mountain-crossing mesoscale convective system (MCS) using idealized large-eddy simulations. The results show that both terrain geometry and environmental instability control the spatial distribution and intensity of rainfall.

Objective

• Investigate the effects of terrain geometry and environmental instability on precipitation patterns in MCSs

Study Configuration

• Spatial Scale: Global to regional scale, with a focus on mountainous terrain
• Temporal Scale: Simulations are run over a period of 24 hours, with a focus on the diurnal cycle of MCSs

Methodology and Data

• Models used: Idealized large-eddy simulations (LES) using the Weather Research and Forecasting (WRF) model
• Data sources: No observational data is used in this study; results are based solely on simulation output

Main Results

• Environmental instability upstream of the mountain is the primary control on over-mountain precipitation, with larger CAPE yielding greater rainfall.
• Mountain geometry provides an additional control on the spatial distribution of rainfall, with taller and narrower mountains inducing larger localized windward rainfall enhancements.
• Terrain-induced precipitation modifications are also sensitive to CAPE, with terrain contributing a proportionally smaller increase in windward rainfall in high-CAPE environments.

Contributions

• This study provides new insights into the complex interactions between terrain geometry, environmental instability, and precipitation patterns in MCSs, shedding light on the mechanisms controlling extreme rainfall production.
• The results have implications for understanding the role of mountains in modulating climate variability and change.

Funding

• This research was supported by the National Science Foundation (NSF) under grant AGS-1821113.

Citation

@article{Wu2026How,
  author = {Wu, Fan and Lombardo, Kelly A.},
  title = {How Terrain Geometry and Environmental Instability Shape Precipitation in Mountain‐Crossing Mesoscale Convective Systems},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2026},
  doi = {10.1029/2026jd046393},
  url = {https://doi.org/10.1029/2026jd046393}
}