Western Disturbances

Western Disturbances

News: Under the influence of two consecutive western disturbances, New Delhi is in for a wet spell.

Western Disturbances
• A western disturbance is an extratropical storm originating in the Mediterranean region that brings sudden winter rain to the northwestern parts of the Indian subcontinent.
• It is a non-monsoonal precipitation pattern driven by the westerlies.The moisture in these storms usually originates over the Mediterranean Sea, the Caspian Sea and the Black Sea.
• Extratropical storms are global phenomena with moisture usually carried in the upper atmosphere, unlike their tropical counterparts where the moisture is carried in the lower atmosphere.
• In the case of the Indian subcontinent, moisture is sometimes shed as rain when the storm system encounters the Himalayas.
• Western disturbances are more frequent and stronger in the winter season.
• Western disturbances, specifically the ones in winter, bring moderate to heavy rain in low-lying areas and heavy snow to mountainous areas of the Indian Subcontinent.
• They are the cause of most winter and pre-monsoon season rainfall across northwest India.
• An average of four to five western disturbances forms during the winter season.
• Precipitation during the winter season has great importance in agriculture, particularly for the rabi crops.
• Wheat among them is one of the most important crops, which helps to meet India’s food security.