Guwahati, April 19: After five consecutive years of below-normal monsoon rainfall, the Northeast may see a good monsoon season (June-September) this year, but it could be a mixed bag for Assam.
The IMD’s seasonal forecast shows above-normal rainfall activity during the monsoon in some parts of the northeastern region, unlike the rest of India where the prediction is for below-normal rainfall.
“The spatial distribution suggests that below-normal seasonal rainfall is most likely over many parts of the country except some areas over northeast, northwest and South Peninsular India, where normal to above-normal rainfall is likely,” according to the first stage forecast.
While some areas of the region is expected to get good monsoon rains, parts of western Assam and eastern most parts may still see deficit seasonal rainfall.
Meghalaya, Tripura and Mizoram may also get below-normal monsoon rainfall.
The second-stage forecast for the monsoon is issued by the IMD around the end of May.
Over the country as a whole, the monsoon seasonal rainfall is likely to be 92 per cent of the Long Period Average (LPA), according to the forecast which is based on both dynamical and statistical models.
According to the IMD, the Monsoon Mission Climate Forecast System (MMCFS) suggests the development of El Nino conditions during the southwest monsoon season.
At present, neutral Indian Ocean Dipole (IOD) conditions are present over the Indian Ocean and the latest climate models forecast indicates that the positive IOD conditions – a climate phenomenon where the western Indian Ocean (near Africa) becomes significantly warmer than the eastern Indian Ocean (near Indonesia) – are likely to develop towards the end of the southwest monsoon season.
El Nino refers to the periodic large-scale warming of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, including changes in winds, pressure and rainfall patterns.
While El Nino tends to reduce rainfall, a positive IOD is considered favourable for rainfall in India.
Pre-monsoon rainfall activity in the region has also been ‘largely excess’.
Against the normal of 72.6 mm, Assam received 166.6 mm rainfall during March – an excess of 129 per cent.
From March 1 to April 16, the State has received 68 per cent excess rainfall than normal.
The Northeast has already witnessed five consecutive years of below-normal monsoon rainfall.
Last year, East and Northeast India recorded its second lowest monsoon rainfall (1,089.9 mm) in the last 125 years, after 2013 (1,065.7 mm).
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