The monsoon trough is gradually shifting to its normal position from the Himalayan foothills, setting the stage for widespread rain across northwest India over the coming week, the India Meteorological Department said on Saturday.
Saturday’s heavy downpour in Delhi was directly linked to this shifting pattern, which is expected to bring isolated heavy to very heavy rainfall over Uttarakhand and Himachal Pradesh during the next seven days, IMD officials said.
“The monsoon trough is shifting towards its normal position. There is also a cyclonic circulation over Uttar Pradesh. Continued heavy rain over Delhi was because of these two features,” said M Mohapatra, director general, IMD.
However, there may be temporary relief for hill states. Around August 12-13, another circulation is likely to form over the Bay of Bengal, which will push the monsoon trough south of its normal position and reduce rainfall over the hills, Mohapatra explained.
The current weather pattern shows the monsoon trough running near its normal position at mean sea level, accompanied by multiple atmospheric disturbances across the subcontinent. An upper air cyclonic circulation lies over west Uttar Pradesh while another has formed over south Bihar and adjoining north Jharkhand in lower tropospheric levels.
A separate trough extends from Gujarat to west Uttar Pradesh in lower tropospheric levels, while an upper air cyclonic circulation lies over north interior Karnataka in the middle tropospheric levels and another over south coastal Andhra Pradesh in lower tropospheric levels.
The IMD forecast indicates heavy to very heavy rainfall will continue over sub-Himalayan West Bengal, Sikkim, Bihar, Assam, Meghalaya and Arunachal Pradesh during the next seven days. In contrast, central India and Rajasthan are likely to experience subdued rainfall activities for the next 3-4 days.
A low-pressure area is expected to form over northwest and adjoining west central Bay of Bengal around August 13, while a western disturbance appears as a cyclonic circulation over Kashmir and neighbourhoods in lower tropospheric levels.
Isolated heavy rainfall is likely over Himachal Pradesh on 10 and August 15; Uttarakhand until August 11; Punjab, Haryana, Chandigarh and Delhi on August 10; East Uttar Pradesh on 10, 14 and August 15; West Uttar Pradesh on 10, 12 and August 15; and East Rajasthan on August 15.
Very heavy rainfall is forecast for Jammu and Kashmir during August 13-15; Himachal Pradesh during August 11-14; Uttarakhand on August 10, 11 and 14; West Uttar Pradesh on August 13-14; and East Uttar Pradesh on August 12-13.
