It is an extra tropical storm that originates in the Mediterranean region and brings heavy winter rains to the Indian subcontinent’s northwestern regions.
The westerlies drive a non-monsoonal precipitation pattern.
Extratropical storms are a global phenomena that carry moisture in the high atmosphere, as opposed to their tropical counterparts, which carry moisture in the lower atmosphere.
When a storm system hits the Himalayas, moisture is sometimes released as rain on the Indian subcontinent.
How Western Disturbances are caused:
Western Disturbance is caused by extratropical cyclones that form in the Mediterranean Sea.
A high-pressure area forms over Ukraine and the surrounding region, allowing frigid air from the Polar Regions to enter an area of somewhat warmer air with significant moisture.
This encourages the formation of an eastward-moving extratropical depression by creating favourable circumstances for cyclogenesis in the upper atmosphere.
They make their way across the Middle East, passing via Iran, Afghanistan, and Pakistan on their way to the Indian subcontinent.
Impact:
Plays a key role in bringing moderate to heavy rain to low-lying portions of the Indian Subcontinent, as well as heavy snow to mountainous areas.
Cloudy skies, warmer night-time temperatures, and unexpected rain are frequently linked with this disturbance.
This precipitation is critical in agriculture, particularly for Rabi crops.
Wheat is one of the most significant crops that contributes to India’s food security.
Crop damage, landslides, floods, and avalanches can all be caused by excessive precipitation caused by this disturbance.
It brings cold waves and dense fog to the Indo-Gangetic plains on occasion.
Until another western disturbance disrupts the situation, these circumstances will remain stable.
A transient advancement of monsoon current develops across the region when western disturbances sweep across northwest India before to the onset of monsoon.
