Rain deficit over 9%, northeastern states driest, says Met department
“Deficiency in the northeastern region doesn’t matter much because excess water usually drains as run-off from the hills, but in the plains it would have led to drought,” said an IMD scientist who asked not to be named.
The Southwest Monsoon, which brings rain from June to September, recorded a countrywide deficit of more than 9% this year, with the north-eastern states of Arunachal Pradesh, Assam, Meghalaya, Manipur, Mizoram, Nagaland and Tripura receiving scanty rainfall, according to data from the India Meteorological Department (IMD).
There was an overall 5% monsoon deficit in 2017.
IMD has forecast a normal Northeast Monsoon season between October and December for southern India, with the likelihood of above normal rainfall this winter. Tamil Nadu, coastal Andhra Pradesh, Rayalseema, Kerala and south interior Karnataka receive about 30% of their annual rainfall in this period.
An analysis of the Southwest Monsoon shows Arunachal Pradesh, Assam and Meghalaya received deficient rainfall each monsoon week. “Deficiency in the northeastern region doesn’t matter much because excess water usually drains as run-off from the hills, but in the plains it would have led to drought,” said an IMD scientist who asked not to be named.
Jharkhand and Bihar have been largely dry during the past four months, with Jharkhand receiving normal rainfall only in the first couple of weeks at the start of the season.
Lakshadweep got deficient rainfall throughout the season.
“We have noticed that whenever there is good monsoon over central India, the North-east states do not get enough rain. Out of 36 subdivisions, 26 have good rainfall distribution. Whenever the eastern end of the monsoon shifts towards the Himalayas, there is very good rainfall over the North-east. But this time the trough was near its normal position,” said M Mohapatra, director general, meteorology, IMD.
“The Southwest Monsoon has withdrawn from some parts of Rajasthan, Kutch and north Arabian Sea on September 29, 2018. Conditions are becoming favourable for further withdrawal from the remaining parts of Rajasthan, Punjab, Haryana (including Delhi), Uttar Pradesh, Madhya Pradesh, Gujarat and north Arabian sea during next 2-3 days,” a statement by IMD said.
“In the North-east, there is no heavy dependence on agriculture so we are not expecting any major impact on agriculture... Jharkhand and Bihar will be moderately affected. Groundwater levels will of course be affected in the North-east,” AK Sharma, agro-meteorologist with IMD, said.
IMD’s forecast for the 2018 Northeast Monsoon season over the southern peninsula is most likely to be normal (89% -111%). “There is a tendency for some southern states, especially Tamil Nadu, to receive above normal rainfall this year. We are also expecting weak El Nino conditions,” Mohapatra added.
El Nino is the warming of the Pacific surface waters, which is linked with drought years in India. All El Nino years, however, have not been drought years.
There is a 70% probability of the development of weak El Nino during the October to December season, with these conditions likely to continue in the first quarter of next year, according to Monsoon Mission Climate Forecast System forecast.