In a piece of good news, India can expect above-normal monsoon rains over most parts of the country. The IMD on Monday did its first long-range forecast for the monsoon, which is a four-month season critical for the country’s agrarian economy as it accounts for 70 per cent of the annual rainfall.
“The southwest monsoon is likely to be above normal, mostly on the higher side during June to September. It is likely to be 106% of the long period average (LPA) with a model error of +/-5%,” said Dr M Ravichandran, secretary to the ministry of earth sciences (MoES). The LPA for the country as a whole from 1971-2020 is 87 cm. Seasonal rainfall between 96 to 104 per cent of the LPA is considered to be normal.
Some parts of extreme northwest India, mainly Jammu and Kashmir, as well as northeastern states and Odisha could receive deficient rain. Overall, there is a 61 per cent probability that India could witness higher than normal rains this monsoon. The forecast has come as a relief for parts of Uttar Pradesh and Bihar, which received subpar rains last year.
Conditions favourable for good rains
According to the IMD, unlike last year, when India witnessed a subpar monsoon that ended at 94.4 per cent of the LPA, the overall conditions are favourable for higher rainfall this year.
The prevailing moderate El Nino conditions over the equatorial Pacific Ocean are expected to transition into neutral conditions by the beginning of June, when the monsoon makes its onset. It is likely to further turn into La Nina during the second half of the monsoon around August-September.
El Nino Southern Oscillation (ENSO) is a periodic scientific phenomenon that has a strong impact on the monsoon. While its existing El Nino phase favours deficient rains, the opposite La Nina often leads to above-normal rains.
“We have conducted a study and found that there have been 22 La Nina years from 1951 and most of the years have witnessed above-normal monsoon rains, except for 1974 and 2000. We can expect good rainfall activity over India this monsoon,” said director general of meteorology Dr M Mohapatra.
Apart from La Nina, another phenomenon called the Indian Ocean Dipole (IOD) is also expected to transition into its positive phase; this is also conducive for a good monsoon. The IMD said this time, the snow cover over the Northern Hemisphere during December to January was also less than normal, which also augurs well for the monsoon activity over India.
The IMD will further update its forecast in the last week of May, just before the monsoon gears up to makes its onset over Kerala.
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