Extremely heavy rain seemed to have relented over Uttarakhand and adjoining West Uttar Pradesh, Himachal Pradesh, Punjab and Haryana and Chandigarh on Tuesday but is expected to break out afresh over the rest of Uttar Pradesh, Bihar, North-East India and Sikkim, and last for a couple of days more.

Extreme heavy rain

This followed a day of extremely heavy rain over Himachal Pradesh, Uttarakhand, Chandigarh and West Uttar Pradesh, leading to massive floods and landslides on Monday. Heavy rain lashed Punjab, Haryana, East Rajasthan, Gujarat, Meghalaya, hills of West Bengal, Sikkim, Bihar and Telangana. It was heavy over Delhi, West Rajasthan, East Uttar Pradesh, Madhya Pradesh, Vidarbha, Chhattisgarh, Odisha, Jharkhand, Assam, Arunachal Pradesh, Coastal Andhra Pradesh, Tamil Nadu and the Konkan.

Fresh activity over Bay

The India Meteorological Department (IMD) said on Tuesday that normal rainfall will unfold over the country for the next three days, except over the plains of West Bengal, Jharkhand and Odisha, where it is likely to be below normal. The brief lull would be broken by fresh activity over the Bay of Bengal, as monsoon flows are expected to converge over the Head Bay (off West Bengal-Bangladesh coast) during this period. 

Numerical model predictions by the IMD as well as global models, indicate the formation of a low-pressure area (even a depression) over the Head Bay that will hang in there for a while. It will anchor the flows and drive up the monsoon over East India, Central India, and North-West India.

Western disturbance in action

On Tuesday, the crucial monsoon trough that conjured up some of the worst flooding witnessed in North India, combined with a visiting western disturbance, remained active with its western end to the south of its normal position. Its eastern end lies over land to the north of its normal position, but is compensated by the heavily endowed western end that hosted two cyclonic circulations.

Of these, one lay over North-East Rajasthan while the other was parked over Haryana. The western disturbance lay as a trough lies over East Pakistan, and was able to influence feverish monsoon activity from its perch to this side of the border as it encountered the monsoon easterlies from the Bay of Bengal. Outlook for North-West India for the next five days is fairly widespread to widespread rain with isolated heavy to very heavy falls over Uttarakhand and Uttar Pradesh during next two days and isolated heavy rainfall thereafter. Isolated heavy rain is also likely over East Rajasthan during the next five days. 

Heavy rain for East, North-East

Another region of major rain activity is East and adjoining North-East India, where fairly widespread to light to moderate rainfall with isolated heavy to very heavy rain is forecast for the hills of West Bengal and Sikkim, Assam, Meghalaya, Arunachal Pradesh, Nagaland, Manipur and Bihar for next three days and isolated heavy rainfall thereafter. Isolated heavy rain is likely over Odisha on Friday and Saturday and over Jharkhand from Wednesday to Friday. Isolated extremely heavy rainfall is likely over Arunachal Pradesh, Assam, Meghalaya and the hills of West Bengal and Sikkim on Wednesday.