The September of 2018 has seen a rainfall deficiency of 22.3% until the third week.
It makes it the driest September in 17 years, with rainfall almost a third below normal.
How has rainfall been?
According to IMD (India Meteorological Department) data, 12 of the country’s 36 meteorological subdivisions have registered deficient rainfall.
This is a departure of nearly 20% from the Long Period Average (average annual rainfall for the period 1951-2000).
It covers Gujarat, Bihar, Jharkhand, West Rajasthan, Haryana (including Delhi and Chandigarh), the entire North-East, Rayalaseema and North Interior Karnataka.
South India has been dry this September, with a deficiency of over 46%.
Not much rain is expected in the remainder of the month too leaving September with a deficiency of over 30%.
Never since 2001, with a 35.8% shortfall, has September been so dry.
The month is thus set to end up being the driest September since 2001.
The shortfall has meant that there has been a 9% deficiency in the overall rainfall in June-September monsoon.
Eastern and north-eastern India has a deficiency of almost 25% over the season.
What is the possible reason?
According to the IMD, there were only six significant low pressure systems (LPS) this season.
One or two LPS formed almost every day but most of these were not strong enough to bring in rain.
So the lack of strong LPS developing over the Bay of Bengal side is likely the only cause of low rainfall.
One of the reasons for this is that around the same time, some cyclonic activity in the west Pacific region was taking place.
The moisture over the Bay of Bengal got sucked in by those systems.
Evidently, Japan and Philippines had some good rainfall.
Besides this there might not be any “external cause” behind the low rainfall in this month.
In natural systems like monsoon, a drought can occur once in a few years without any external cause.
So though the rainfall deviation is large, it doesn’t seem to be a result of any major atmospheric abnormality.
Suggestions that a developing weak El Niño in the Pacific Ocean might have forced a suppression of rainfall are ruled out.
Will it affect agriculture?
The poor rainfall activity is unlikely to significantly impact agricultural production.
The main reason for this is that much of kharif plantings happen in June-July.
Most parts, except Bihar, Jharkhand and the North-East states, received enough rains for farmers to take up sowing operations.
Some areas such as Marathwada, North Karnataka and Gujarat (especially Saurashtra) did experience dry spells during the crop’s vegetative growth phase.
But the situation is nowhere close to the drought situation seen in 2014 and 2015.
There are concerns over the cotton crop in Gujarat’s main Saurashtra belt where moisture stress could affect yields.
But fortunately, no large-scale pest attacks have been reported in the country’s major cotton-growing areas this time.
Given all these, this year’s kharif crop would not be as good as in the last two years.
But there is certainly no possibility of a repeat of the 2014 and 2015 drought situations.
Moreover, further rainfalls, as predicted, would help bolster the soil and sub-soil moisture in the coming rabi sowing season.
However, the Australian and U.S.'s meteorology departments have forecasted an El Nino event to take place after November.
El Nino is the abnormal warming of the equatorial Pacific Ocean Waters, seen to adversely impact rains in India.
This could possibly have a bearing on the winter rains, which are crucial for crops such as wheat, mustard and chana.
