IMD forecasts ‘near normal monsoon’, but there are other factors at play: All you need to know

On Monday, April 15, the Ministry of Earth Sciences and Indian Meteorological Department (IMD) said in a statement that India will experience a “near normal” southwest monsoon between June and September.

Experts were concerned about the impact of El Niño on the monsoon in India. However, the IMD says the country will only see weak El Niño conditions in the latter half of the season.

IMD’s southwest monsoon forecast

The IMD, also known as the Met Department, is an organisation under the Ministry of Earth Sciences umbrella. It is the country’s premier agency for weather forecasts, seismology, and other meteorological activity.

It issues the country’s first monsoon forecast in April and the second in June. The IMD uses a number of indicators when compiling the forecast report, namely Sea Surface Temperature (SST), Sea Level Pressure, and Air Temperature.

The IMD model calculates SST  between the North Atlantic and North Pacific during December and January and over the South Indian Ocean during February.

It also records East Asia’s mean Sea Level Pressure over February and March, Northwest Europe’s Land Surface Air Temperature during January, and Equatorial Pacific warm water volume during February and March.

Reporting a 5% margin of error, the IMD said the monsoon will account for 96% of the Long Period Average (LPA).

How IMD measures ‘normal’

The LPA is the average rainfall recorded between June and September calculated for the past 50 years. It helps the IMD create a pattern of rainfall to understand whether or not the precipitation each year was normal, below normal, or excessive.

The current LPA says India receives about 89 cm of rainfall during the season—the volume considered “normal” by the IMD today. Hence, in 2019, the country is expected to receive about 94% of that volume.

The IMD explains that there is a 39% chance of a “near normal” monsoon. India is also facing a 32% chance of “below normal” rain.

Another factor influencing the monsoon is the Indian Ocean Dipole (IOD) or the yearly changes in tropical sea temperature in the western and eastern halves of the Indian Ocean.

The IOD oscillates between negative, neutral, and positive phases that change every few months.

The report adds that the Indian Ocean is currently seeing neutral “IOD conditions”. In the past, positive IOD conditions have been associated with “normal monsoon” in India.

Impact of El Niño on Indian monsoon

The southwest monsoon will only be impacted by weak El Niño conditions. The abnormal warming of the eastern and central Pacific waters is called El Niño.

The warm waters trigger greater evaporation and cloud formation towards South America, resulting in floods. However, the stronger the El Niño effect on South America, the more deprived east Asia is of convection currents.

Hence, there is an inverse relationship between Indian monsoons and El Niño; 13 of the last 20 droughts in India occurred during El Niño.

However, IMD clarifies that El Niño predictions made in February and March are generally more uncertain than ones in made in June.

Impact of the southwest monsoon on farmers and RBI

Thiruvananthapuram, Bengaluru, Chennai, Panaji, Mumbai, Surat, Guwahati, Kolkata, Ahmedabad, and the Andaman and Nicobar islands should start seeing rainfall in the last week of May and first 10 days of June.

Jaipur, Delhi, Lucknow, Varanasi, Patna, Bhopal, Nagpur, Shimla, Srinagar, and Chandigarh will experience normal monsoon post June 10.

IANS reported that a near normal monsoon will “provide some comfort to the RBI and may prompt it to cut policy rates in August, instead of the next policy meet scheduled in June”.

The favourable monsoon will be welcome news for the RBI as rainfall directly influences agricultural output and inflation in India.

However, Crisil Chief Economist D K Joshi tells Mint that the economic relief will depend on how evenly distributed the rainfall is.

IMD said, “Overall, the country is expected to have well distributed rainfall scenario during the 2019 monsoon season, which will be beneficial to farmers in the country during the ensuing kharif season.”

Both, the Congress and BJP manifestos have promised water conservation and support for farmers.

The Congress has proposed a minimum basic income scheme and loan waivers, while the BJP has promised to complete pending irrigation projects and increase investment into infrastructure.

Regardless of who comes to power, issues plaguing the environment and farmers in the country need to be addressed.


Rhea Arora is a Staff Writer at Qrius

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