A Western Disturbance will start affecting the western Himalayas from February 23 onwards and will give widespread rain and snow to the three hilly states of Himachal Pradesh, Jammu & Kashmir and Uttarakhand on February 24 and 25. Gradually, this system will shift towards the east along the foothills of the Himalayas and cause good rain over the areas of eastern Uttar Pradesh and Bihar around February 26 and 27.
Since the last few days eastern Uttar Pradesh was particularly deprived of rain and remained dry for a long period. But, with the system affecting the region, good amounts of rain is expected. Currently, the areas of Jammu & Kashmir, Himachal Pradesh and Uttarakhand are experiencing a 48 hours of sunny weather, but that too will come to an end after the system affects the western Himalayan region.
Whenever, a Western Disturbance moves towards the east it usually bifurcates into two systems. One of them moves to the south of the Himalayas and affects the foothills of the Himalayan region, i.e. northern parts of Uttar Pradesh and Bihar. Another system moves to the northern part of the Himalayas and affects the areas of Nepal and China. Western Disturbances are low pressure systems, which originate in the Caspian Sea or Mediterranean Sea. These systems are called as Western Disturbances or WDs by Indian meteorologists since they always travel from the west to the east.