Chasing monsoon 2019: July deficit means 90% chance of falling below normal

If June rainfall remains below 100 mm, it would be fourth time in last 118 years

By Richard Mahapatra
Published: Monday 01 July 2019

Monsoon 2019 completed a quarter of its four-month season with a deficit of 33 per cent. But the most critical month of this season is July, accounting for the highest rainfall — a third of the total — in the season. A deficit in July rainfall has historically been associated with an overall deficit monsoon and severe droughts.

India Meteorological Department (IMD) already indicated a below-normal July rainfall. It is usual for a monsoon break in either mid-July or sometimes in August.

A deficit July monsoon, however, has been a cause of worry in both agricultural and meteorological terms. First, in India’s cropping cycle — especially for paddy — this month’s rainfall is crucial. In July, farmers transplant paddy crops that need regular showers.

This year, there is another worry for farmers: Sensing the late onset and tardy progress in monsoon, states advised farmers to delay sowing. Paddy was sown on about 27 lakh hectares by June 28 — 8.45 lakh Ha short of last year. Almost all crops have reported a drop in area under sowing.

This means, farmers would begin sowing almost a month after what is normal. In July they would have to take up transplanting as well. Their dependence on July rain will be much more desperate. If In case of erratic rainfall or extreme events, crops will be damaged before they mature.

Deficits in monsoon in July have caused six of India’s worst droughts between 1877 and 2005, according to analysis of IMD rainfall data by the Indian Institute of Tropical Meteorology (IITM), Pune.

IITM scientists studied overall monsoon outcomes for rainfall above or below normal for June, July as well as both, using data since 1871, in 2013. If there was a deficit in July, chances of overall deficiency soared to more than 90 per cent, they found.

Let’s look at two of the country’s worst droughts:

  • 1987 – July rainfall deficit was 26 per cent; overall monsoon was 18 per cent below normal
  • 1972 –July deficit at about 30 per cent; overall monsoon ended 25 per cent below average.

The study also found that with deficit rainfall in June, chances of a deficit in overall monsoon was at around 77 per cent.

Back to 2019

By June 28, the monsoon was at a 36 per cent deficit. IMD’s map of monsoon progress and actual rainfall, issued June 27, was scary: Only five hydromet subdivisions of a total 36 reported normal or above rainfall.

Private forecaster Skymet Weather Services predicted a 33 per cent deficit by June 30 as rains  picked up across India.

By June 27, the actual rainfall was 86.3 mm, compared with a normal 135.6 mm. If it remained below 100 mm even after June 30, this would have been only the fourth such June in the last 118 years; and third since 1901 — 1905 (88.7 mm), 1926 (97.6 mm) and 2009 (85.7 mm). Those were also among India’s worst drought years.

Whenever the deficit in June rainfall exceeded 30 per cent in the past 146 years, it either led to a below-normal monsoon or drought, except in 1923, 1924 and 1926, according to IMD.

The June deficit comes at a time when more than 44 per cent of India's areas were under various degrees of drought conditions (abnormally dry to exceptionally dry) as of June 10, 2019 — that is nearly 11 percentage point more than a year ago, according to the Drought Early Warning System (DEWS).

If the deficit continues in July, most districts experiencing a drought in June would stare a multi-year drought — drought conditions over 24 months.

Multi-year droughts have increased in frequency in recent decades, according to an analysis of droughts that hit India between 1901 and 2010 by the Earth System Science Organization of the Ministry of Earth Sciences showed.

Twelve multi-year droughts were recorded during 1951-2010 while there were only three such droughts during 1901-1950. The analysis also showed an increase in drought frequency during 1977-2010.

This increase was more pronounced over central and peninsular India. The recent spells of droughts were also reported in these areas. There was also an increase in areas hit by moderate droughts.

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