Come September, monsoon may turn out to be normal

India Meteorological Department on Thursday said the monsoon this year could be lower than normal after the country received its lowest rainfall in last 122 years during August. September might witness normal precipitation, though. However, this season, it may not be deficient, which is below 90 per cent of normal.

Addressing media on the outlook for September, Mrutyunjay Mohapatra, Director-General of IMD. said: “September is likely to witness normal rainfall in the range of 91-109 per cent of the long period average (LPA) of 167.9 mm.” He said even if the rainfall in September is to remain on the higher side, the June-September seasonal rainfall average is expected to be “below normal” for the season.

• Also read: Pan-India August monsoon deficit at 32%; South India gets only 38% of normal rain

93.6% of normal predicted

Releasing the rainfall data upto August 31 since season began from June 1, he said the country as a whole has received 10 per cent lower than normal rain whereas only August was deficient by 36 per cent.

Considering IMD’s forecast on higher side (109 per cent) of LPA, maximum 183.01 mm rainfall is expected in September and if its is added with actual rainfall (629.7 mm) of June-August period, the total could be 812.71 mm, which is 93.6 per cent of the normal. The weather bureau has defined 90-95 per cent of season’s LPA of 868.6 mm as “below normal” and 96-104 per cent under “normal” category.

The IMD’s forecast in April though based on both dynamical and statistical models suggested monsoon seasonal rainfall to be 96 per cent with a model error of plus/minus 5 per cent. There was 51 per cent forecast probability of a lower than normal rainfall. Private weather forecaster Skymet had predicted “below normal” monsoon for 2023.

• Also read: Indian Ocean Dipole turns positive, may prove too late for monsoon 

El Nino at play

Mohapatra said considering possible rainfall in east and north east region, the key cereal of kharif season paddy crop may not be impacted, but he said experts could throw more light on it.

Normal to above normal rainfall during September is most likely over many parts of north-east India, adjoining east India, foothills of Himalayas and some areas of east of central India and south peninsular India (including Uttar Pradesh, Bihar, Jharkhand, West Bengal, Odisha, northern Madhya Pradesh, northern Chhattisgarh, northern Andhra Pradesh, south Telangana, north and south interior Karnataka and north Tamil Nadu).

Below normal rainfall probability is seen over areas of the remaining part of the country – Punjab, Haryana, Rajasthan, Gujarat, Maharashtra, east Madhya Pradesh, coastal Karnataka, Kerala and some areas in south Tamil Nadu.

Stressing that El Nino was the major factor that lowered the August rainfall, other factors like lower than normal number of low pressure, negative Madden Julian Oscillation (MJO) and neutral Indian Ocean Dipole (IOD) too have contributed.

However, even though El Nino conditions to be stronger onwards, the IOD – the difference in sea surface temperature of Arabian Sea and the Bay of Bengal – has started turning positive, which could counter the El Nino impact, Mohapatra said.