The core of the monsoon has shifted to North-West India, East and North-East India along with the land-based trough that serves as the backbone, while rainfall has weakened over Peninsular India and may stay as such for the next week or so before a low-pressure area from the Bay of Bengal likely reverses the situation into early August. This (Friday) morning, interaction of a couple of western disturbances – a cyclonic circulation over Himachal Pradesh and an incoming one from Afghanistan-Pakistan - plus another circulation over Jharkhand with the monsoon trough promise to be the show-stopper across the hills and plains of North-West India to East and North-East India.

Widespread rain forecast

India Meteorological Department (IMD) has predicted fairly widespread to widespread light to moderate rainfall with isolated heavy falls, thunderstorms and lightning over Jammu & Kashmir until Sunday; over Himachal Pradesh and Rajasthan until Monday; Uttarakhand and Punjab tomorrow (Saturday) and Sunday; and Haryana, Chandigarh and West Uttar Pradesh today (Friday). Isolated very heavy rainfall is forecast over Rajasthan today and tomorrow; and over Jammu & Kashmir, today.

Central India too may gain

To the East and South, fairly widespread to widespread light to moderate rainfall, thunderstorms and lightning are likely over Chhattisgarh, Vidarbha and Madhya Pradesh during the next five days. Isolated heavy rainfall is likely over Chhattisgarh and Madhya Pradesh until Monday; and over Vidarbha from tomorrow (Saturday) to Monday. Fairly widespread to widespread rainfall is likely over Odisha, Bihar, Jharkhand, West Bengal and Sikkim during the next five days.

Heavy falls for East India

Isolated very heavy rainfall is forecast over Odisha from today until Sunday while it would be fairly widespread to widespread light or moderate rainfall with heavy falls over Arunachal Pradesh, Assam, Meghalaya and Nagaland, Manipur, Mizoram and Tripura during the next five days. Isolated very heavy falls are forecast over Assam and Meghalaya today (Friday) and over Arunachal Pradesh both today and tomorrow, the IMD said.

Deficit down in North-West

The shifting of the monsoon trough to the North (towards its normal position) has already brought badly-needed rain to North-West India and East and North-East India. The rain will continue varyingly over these areas for the next few days as well, even up to five days in some. The rain deficit has been brougt down to four per cent over North-West India as on Thursday (July 21) even as Uttar Pradesh still awaits due share. The surplus over Central India and South Peniinsula has been affected after the rain belt moved out from there to its normal alignment over North-West India.

Non-seasonal in South

Over the South Peninsula, rains have weakened, with a non-seasonal and monsoon-unfriendly trough (identified best with pre-monsoon phase) running down from South Interior Karnataka to the Comorin. It reflects the inability of the monsoon flows to converge along the monsoon offshore trough, which is conspicuous by its absence, and which explains the weak monsoon conditions. It is into this background that models (including IMD’s numerical predictions) indicate the formation of a low-pressure area over the South Bay of Bengal (again, a location not usually identified with the monsoon) and curling towards the coast of Chennai by the month-end, triggering a wave of rainfall over the South Peninsula.