Western disturbances and climate variability: a review of recent developments

Hunt, K. M. R. ORCID: https://orcid.org/0000-0003-1480-3755, Baudouin, J.-P., Turner, A. G. ORCID: https://orcid.org/0000-0002-0642-6876, Dimri, A. P., Jellani, G., Pooja, Chattopadhyay, R., Cannon, F., Arulalan, T., Shekhar, M. S., Sabin, T. P. and Palazzi, E. (2025) Western disturbances and climate variability: a review of recent developments. Weather and Climate Dynamics, 6 (1). pp. 43-112. ISSN 2698-4016 doi: 10.5194/wcd-6-43-2025

Abstract/Summary

Western disturbances (WDs) are synoptic-scale weather systems embedded within the subtropical westerly jet. Manifesting as upper-level troughs often associated with a lower-tropospheric low over western or northern India, they share some dynamical features with extratropical cyclones. WDs are most common during the boreal winter (December to March), during which they bring the majority of precipitation – both rain and snow – to the Western Himalaya, as well as to surrounding areas of north India, Pakistan and the Tibetan Plateau. WDs are also associated with weather hazards such as heavy snowfall, hailstorms, fog, cloudbursts, avalanches, frost, and coldwaves. In this paper, we review recent developments in understanding WDs and their impacts. Over the last decade, recent studies have collectively made use of novel data, novel analysis techniques such as tracking algorithms, and the increasing availability of high-resolution weather and climate models. This review is separated into six main sections – structure and thermodynamics, precipitation and impacts, teleconnections, modelling experiments, forecasting at a range of scales, and paleoclimate and climate change – each motivated with a brief discussion of the accomplishments and limitations of previous research. A number of step changes in understanding are synthesised. Use of new modelling frameworks and tracking algorithms has significantly improved knowledge of WD structure and variability, and a more frequentist approach can now be taken. Improved observation systems have helped quantification of water security over the Western Himalaya. Convection-permitting models have improved our understanding of how WDs interact with the Himalayas to trigger natural hazards. Improvements in paleoclimate and future climate modelling experiments have helped to explain how WDs and their impacts over the Himalaya respond to large-scale natural and anthropogenic forcings. We end by summarising unresolved questions and outlining key future WD research topics.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/119384
Identification Number/DOI	10.5194/wcd-6-43-2025
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Uncontrolled Keywords	western disturbances, WDs, India, winter, Himalaya, western Himalaya, tracking, modelling
Publisher	European Geophysical Union
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