Western Disturbances
Origin, Mechanism, and India's Climate
Western Disturbances (WDs) are extratropical cyclonic storms that originate over the Mediterranean Sea, the Caspian Sea, and the Atlantic, and travel eastward along the subtropical westerly jet stream (typically at 25°N–35°N, 200 hPa level). When WDs interact with the warm, moisture-bearing Arabian Sea winds over northwestern India, they produce significant rainfall, snowfall, and hailstorms. WDs are the primary source of winter rainfall for the Rabi crop belt (wheat in Punjab, Haryana, Uttar Pradesh) and snowfall for the Himalayan glaciers, which recharge the Indus, Ganga, and Yamuna systems. WDs typically peak between December and February and weaken by late March as the jet stream migrates northward.
- WDs are embedded in the subtropical westerly jet stream at ~250–300 hPa
- Average number of WDs per year: 12–15, with 6–7 causing significant impact
- The March–April WD activity is increasing in frequency and intensity — attributed to a 1.5°C warming of the Indian Ocean and Mediterranean
- WD-induced rainfall is non-monsoonal and critical for Rabi crops: ~70% of Punjab-Haryana wheat depends on WD-related rain/snow
- Fog in the Indo-Gangetic Plain during winter: a secondary consequence of WDs bringing moisture at low altitudes
● Tracked since March 06, 2026 · last seen March 21, 2026 · updates as the daily brief publishes