The southwest monsoon season over India has ended with marginally above-normal rainfall. Quantitatively, the rainfall during this season, which officially ended on Friday, was 925mm, or 6 per cent above the long period average (LPA), India Meteorological Department (IMD) officials said.
In June, the IMD predicted the seasonal rainfall to be normal or range between 96-104 per cent of the LPA.
The rainfall in the past four months remained either normal or above over the northwest India (1 per cent), central India (19 per cent) and south peninsular India (22 per cent). This covers a total of 30 states or Union Territories.
However, despite a promising seasonal start in June–when it received +22 per cent above-normal rainfall–the rainfall activity over the east and northeast India region had declined since July. The seasonal rainfall here ended at -18 per cent.
Nearly 43 per cent area of the country received normal rainfall and 40 per cent area recorded excess rainfall this season. Uttar Pradesh, Jharkhand, Bihar, Manipur, Mizoram and Nagaland–the six driest states of this season–accounted for 17 per cent of the country’s rain-deficient areas, the IMD officials said.
“Except for the latest two low-pressure systems formed in September, all remaining systems did not bring rainfall over UP as they followed a west-northwestwards track. Thus, the overall Indo-Gangetic plains consistently reported below-normal rainfall. It was only in the September 15-25 spell that UP’s rainfall deficit got somewhat compensated,” said Mrutyunjay Mohapatra, director-general of the IMD.
From a rainfall deficit of -48 per cent recorded during most days of July and August, UP’s seasonal rainfall ended at -28 per cent, the IMD’s rainfall data showed.
Even though there were three low-pressure systems in the Bay of Bengal in September, their regular interactions with the passing western disturbances caused widespread rainfall over the central and northwest India regions, the IMD chief noted. In September, there were 16 low-pressure days, which was almost normal. The country recorded 181mm or 8 per cent above-normal rainfall in September.
With the IMD expecting the formation of a fresh cyclonic circulation in the Bay of Bengal during the upcoming weekend, Mohapatra said that any further monsoon withdrawal was unlikely for at least a week.
He said, “As the system formed in the Bay of Bengal will move westwards in the coming days, rainfall is likely to occur over Odisha, Jharkhand, UP and Madhya Pradesh from October 4 onwards. The presence of this system will stall the monsoon withdrawal from parts of central India. Unless it moves away and dissipates completely, there are no chances of monsoon withdrawal from central India at least till October 13.”
This essentially means that the monsoon withdrawal will continue to remain slow and linger on till the second week of October, as has been the scenario in the past few days. The normal date for the completion of monsoon withdrawal from the country is October 15.