The monsoon has run through the remaining parts of Rajasthan, Haryana and Punjab on Friday, thus covering the entire country at least 12 days ahead of the normal date of July 8. Earlier in 2013, it had achieved the feat as early as June 16, according to Mrutyunjay Mahapatra, Director-General, India Meteorological Department (IMD).

A low-pressure area forming over the Bay of Bengal and moving West-North-West over land followed by a cyclonic circulation that dropped anchor over Central India had hastened the monsoon advance, Mohapatra said in New Delhi on Friday. Rains so far have been quite good and well-distributed, he added.

As many as 31 out of 36 meteorological subdivisions have already received normal to large excess rain. This is certainly beneficial for sowing purposes. June is the main season for sowing for major parts of the country except West Rajasthan. So no adverse impact to sowing is anticipated anywhere.

La Nina, common determinant

Significantly, the year 2013’s monsoon had surprised the IMD’s early forecast estimates (98 per cent) way up on the upside, delivering 106 per cent for the June-September season. Private forecaster Skymet Weather was more generous that year, projecting 103 per cent in its initial outlook.

The monsoon had made an onset on June 1 just as this year, two days ahead of forecasts. What triggered the surplus was a moderate La Nina in the tropical Pacific. A La Nina event, likely not as strong as that year, may all but have been declared this year too, with the Australian national forecaster officially setting up a watch.

On Friday, the rain-facilitating trough over North India ran down from Punjab to East Bihar across Haryana and Uttar Pradesh. This was widely at variance with the familiar alignment from West Rajasthan to head Bay of Bengal, found to be the most ideal for ensuring a good monsoon over Central India.

Violent weather in East

The shift of the trough northward of the normal is leading to convergence of strong southerly to south-westerly winds from the Bay of Bengal over North-East and adjoining East India, resulting in continued widespread rainfall with isolated heavy to very heavy rainfall during the next three days.

Isolated extremely heavy rainfall is also likely over Bihar, hills of West Bengal, Sikkim, Assam and Meghalaya on Friday and Saturday. The transition phase of pre-monsoon to monsoon proved deadly over Bihar and Uttar Pradesh on Thursday with lightning and thunderstorms taking a toll of 116.

On Friday, Bihar revised the death toll in the lightning incidents in various districts from 85 to 92, agency reports said. Neighbouring Uttar Pradesh saw at least 24 lose their lives and 12 injured.

Fairly widespread to widespread rainfall with isolated heavy to very heavy falls has been forecast over East Uttar Pradesh during the next 3-4 days. Isolated heavy to very heavy rainfall is likely over West Uttar Pradesh during Sunday-Monday. Thunderstorms/lightning may line up over East Uttar Pradesh, Bihar and Jharkhand during the next 4-5 days.

Active in South, too

Meanwhile in the South, fairly widespread to widespread rainfall with isolated heavy to very heavy rainfall has been forecast during the next 4-5 days as an ongoing rain wave envelopes more parts of the region. Isolated extremely heavy rainfall is the call for Kerala on Friday and Saturday.