The rain-driving monsoon trough has shifted slightly northwards from central India where it has been very active for the past week or so, and will continue to shift further northwards to its normal position during next 2-3 days, India Meteorological Department (IMD) said on Monday. This will also bring the heavy rain belt to north-west India, east and north-east India, parts of which are still reeling under deficit despite the glut elsewhere.

Surplus in south, central India

The rain-deficit meteorological subdivisions as on Monday are East Uttar Pradesh (-71 per cent); West Uttar Pradesh (-56 per cent); Jharkhand (-49 per cent); Bihar (-47 per cent); West Bengal (-45 per cent); and Nagaland-Manipur-Mizoram-Tripura region(-25 per cent). In surplus to start with, east and north-East slipped fast into deficit after rain clouds left it for central India and adjoining west India in end-June and into July.

The rainfall situation for the country as a whole continues to be above-normal to the extent of 13 per cent, mainly on account of surplus of 38 per cent over the South Peninsula and 33 per cent over central India. As for north-west India, the deficit has come down to -8 per cent as on Monday. But this region continue to be hobbled by the large deficit over the large State of Uttar Pradesh.

Low-pressure area

The monsoon is being anchored by a low-pressure area over south-east Madhya Pradesh embedded into the monsoon trough across central India even as a rain-spewing depression left Gujarat, stepped out into the Arabian Sea, and weakened on Monday. Their combined influence brought heavy to very heavy rain to Madhya Pradesh, Vidarbha, Chhattisgarh, Coastal Andhra Pradesh, and Coastal and South Interior Karnataka, and heavy rain over west Rajasthan, Madhya Maharashtra, Odisha, east Gujarat, Telangana and Tamil Nadu during the 24 hours ending on Monday morning.

Heavy to very heavy rain

Meanwhile, the incoming monsoon trough will drag the belt of heavy rain along with it towards north-west India from Tuesday. Rainfall will also increase over the North-Eastern States principally due to the expected wobbling movement of the current ‘low’ towards the region over the next few days. Parts of east-central India too will get heavy rain during the period. Presence of the ‘low’ would be too close for comfort for the Bay of Bengal to conjure up a successor, though it will continue to supply enough moisture and clouds into the region and sustain the monsoon.

Brief weak phase soon?

The US Climate Prediction Centre sees the monsoon going into a weak phase briefly over Peninsular India even as rains will get active over north and east India. A couple of other models saw rain breaking out afresh over the East Coast (North from Tamil Nadu), a typical situation known to evolve when the monsoon becomes weak over other parts of the country. But rains may come back to the South Peninsula from July 28, increase further and sustain as such at least until August 16, according to these models.