Conditions favour a broad-scale advance of the monsoon

The weather-altering Madden-Julian Oscillation (MJO) wave is expected to move across the West Equatorial Indian Ocean and adjoining Arabian Sea during the next two to three days and revive the monsoon circulation.

Ahead of this, pilot rains are lashing the West Coast and parts of the East Coast already. This is likely to scale up in the next few days, notably from Sunday, going by the India Met Department’s (IMD) forecast.

Favourable conditions

The IMD has also indicated development of helpful cyclonic circulations over East India strengthening the monsoon easterlies blowing in from the Bay of Bengal.

These winds bring the seasonal rains to East India, Central India and, in combination with the monsoon south-westerlies from the Arabian Sea, rain over West Madhya Pradesh, Gujarat and later Rajasthan. Thus, conditions are becoming favourable for the advance of the monsoon into remaining parts of Assam, Maharashtra, Chhattisgarh, Odisha, West Bengal and parts of Jharkhand, Bihar and Madhya Pradesh from this weekend. As for Monday, the IMD has forecast heavy to very heavy rain at isolated places over the hills in Bengal and Sikkim in the East, and Coastal and South Interior Karnataka and Kerala in the South, representing a broad-scale advance.

Milestone entries

The same day, heavy rain may lash isolated places over Bihar, Jharkhand, plains of Bengal, Odisha, Arunachal Pradesh, Assam, Meghalaya, Nagaland, Manipur, Mizoram, Tripura, Gujarat Region, Konkan and Goa.

Bihar in the East and Gujarat in the West would mark milestones for the monsoon as it braces to enter Uttar Pradesh and the rest of North-West India, and Gujarat State, Saurashtra and Kutch in West India.

The IMD sees the monsoon announcing its arrival with isolated heavy falls over East Uttar Pradesh during Tuesday to Thursday; fairly widespread with isolated heavy over Central India; and isolated to scattered over North-West India.

Heavy rain

During this three-day period, widespread rainfall with isolated heavy falls is also forecast along the West Coast, while it will be fairly widespread with isolated heavy fall over the rest of South India.

This would come about with the likely formation over land of a low-pressure area over the East Uttar Pradesh-Madhya Pradesh border, which gathers strength to the South of Allahabad, and travels straight until Kota, Rajasthan.

Heavy to very rain may lash isolated places along this track, with even eastern parts of Gujarat and adjoining West Madhya Pradesh finding themselves at the receiving end eight to nine days from now.

Meanwhile, an ensemble model of the US National Centres for Environment Prediction said that the monsoon would maintain an active to strong phase over the northern half of the country into the first week of July.

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