Taylor et al. (2026) Wind shear enhances soil moisture influence on rapid thunderstorm growth

Identification

• Journal: Nature
• Year: 2026
• Date: 2026-03-04
• Authors: Christopher M. Taylor, Cornelia Klein, Emma J. Barton, Sebastian Hahn, Wolfgang Wagner
• DOI: 10.1038/s41586-025-10045-7

Research Groups

• UK Centre for Ecology & Hydrology, Wallingford, UK
• National Centre for Earth Observation, Wallingford, UK
• Department of Geodesy and Geoinformation, Technische Universität Wien, Vienna, Austria

Short Summary

This study reveals that wind shear significantly enhances the influence of soil moisture (SM) contrasts on the rapid growth of thunderstorms, particularly for extreme events, by modulating mesoscale circulations that promote deep convection. Analyzing 2.2 million afternoon events across sub-Saharan Africa, the authors found 68% more extreme initiations under favorable soil conditions when wind shear was strong.

Objective

• To investigate the extent to which convective initiation (CI) is favored over drier soil, particularly exploring the mediating effect of vertical wind shear on soil moisture (SM)-CI relationships.

Study Configuration

• Spatial Scale: Sub-Saharan Africa (south of 25° N), with analysis focusing on mesoscale (tens of kilometers) patterns within 400 km × 400 km domains around CI events. Data resolutions varied from 3-5 km (satellite imagery) to 0.1° (precipitation) and 1° (reanalysis winds).
• Temporal Scale: A 21-year period (2004–2024) for CI events, with afternoon events (12:00–18:00 local time) analyzed. Satellite data had 15-minute resolution, precipitation data 30-minute resolution, and lightning data for 6 months (July–December 2024).

Methodology and Data

• Models used: ERA5 (5th European Centre for Medium-Range Weather Forecasts Reanalysis) for low-level (100 m) and mid-level (650 hPa) winds, and for climatological atmospheric profiles used in parallax correction.
• Data sources:
  • Meteosat Second Generation (MSG) series: High-resolution (15 min, 3–5 km) satellite imagery for cloud-top temperature (used for CI identification and cooling rates) and clear-sky daytime land-surface temperature (LST).
  • Advanced Scatterometer (ASCAT) on Metop satellites: Surface soil moisture (SSM) at 15 km spatial resolution (6.25 km sampling), typically around 09:30 local time.
  • Meteosat Third Generation (MTG): Continuous lightning data (from July 2024).
  • Integrated Multi-satellitE Retrievals for GPM (IMERG): Precipitation data (30 min, 0.1° grid).
  • ETOPO1 topography dataset: 1 arcminute resolution for topographic height.

Main Results

• Extreme convective initiation (CI) events are significantly favored over soil moisture (SM) contrasts, with this influence enhanced by wind shear.
• For strong wind shear (>12 m/s), the probability of a CI being classified as extreme is 68% higher for favorable (drier) SM configurations compared to unfavorable ones.
• The greatest vertical storm growth occurs when SM-driven circulations oppose the direction of shear-induced cloud displacement, enhancing cloud-relative updraft inflow.
• When mid-level winds oppose low-level flow (reversed shear), rainfall is strongly organized over dry soils (Pearson correlation coefficient r(SM,P) = -0.85), and lightning activity is tightly localized within the driest soil pixels.
• In the absence of directional shear, rainfall maxima occur over relatively wet soil, leading to a positive spatial SM-P correlation (r(SM,P) = 0.49).
• CI consistently occurs over locally drier soil (ΔSM < 0) across sub-Saharan Africa, outside of mountainous regions.
• Tropical North Africa exhibits widespread strongly negative spatial SM-P correlations, attributed to a significant contribution of reversed mid-level winds, which leads to particularly rapid thunderstorm development in this region.

Contributions

• This study is the first to reveal the important mediating effect of vertical wind shear on soil moisture-convective initiation (SM-CI) relationships.
• It demonstrates that SM patterns strongly influence the vertical growth of storm clouds, disproportionately affecting the fastest-growing thunderstorms.
• Provides a dynamical explanation for why tropical North Africa exhibits the strongest negative spatial SM-P feedbacks globally.
• Reinterprets previous global observational analyses of SM-P feedbacks by integrating the role of directional wind shear.
• Highlights the potential for incorporating land-surface state information into artificial intelligence-based or numerical weather prediction models to improve fine-scale prediction of hazardous thunderstorm initiation, particularly for rapidly developing storms.

Funding

• UK Natural Environment Research Council (NE/X006247/1, NE/W001888/1, NE/X017419/1, NE/X018520/1)
• Met Office on behalf of the Foreign, Commonwealth & Development Office under the WISER Early Warnings for Southern Africa (EWSA) project.

Citation

@article{Taylor2026Wind,
  author = {Taylor, Christopher M. and Klein, Cornelia and Barton, Emma J. and Hahn, Sebastian and Wagner, Wolfgang},
  title = {Wind shear enhances soil moisture influence on rapid thunderstorm growth},
  journal = {Nature},
  year = {2026},
  doi = {10.1038/s41586-025-10045-7},
  url = {https://doi.org/10.1038/s41586-025-10045-7}
}