El Niño and Indian Ocean Dipole likely to cause extreme variability in monthly rainfall distribution
Skymet, India’s weather forecasting and agriculture risk solution company, has released its monsoon forecast for 2023. The company expects the upcoming monsoon to be ‘below normal’ to the tune of 94% of the long-period average (LPA) for the 4-month long period from June to September.
The spread of below normal being 90-95% of LPA. Skymet had assessed the monsoon 2023 to be sub-par in its earlier forecast released on January 04, 2023, and the current assessment retains the same.
Jatin Singh, Managing Director of Skymet, said that the end of La Niña and the increasing likelihood of El Niño may lead to a weaker monsoon. Besides El Niño, other factors influencing monsoons include Indian Ocean Dipole (IOD), which has the potential to steer monsoon and negate the ill effects of El Niño when sufficiently strong. IOD is neutral now and is leaning to turn moderately positive at the start of the monsoon. El Niño and IOD are likely to be ‘out of phase’ and may lead to extreme variability in the monthly rainfall distribution. The second half of the season is expected to be more aberrated.
The monsoon is crucial for India’s agriculture and economy, and a weak monsoon can lead to lower crop yields and water scarcity.
According to Skymet, Monsoon probabilities for JJAS are:
● 0% chance of excess (seasonal rainfall that is more than 110% of LPA)
● 15% chance of above normal (seasonal rainfall that is between 105 to 110% of LPA)
● 25% chance of normal (seasonal rainfall that is between 96 to 104% of LPA)
● 40% chance of below normal (seasonal rainfall that is between 90 to 95% of LPA)
● 20% chance of drought (seasonal rainfall that is less than 90% of LPA)
On a monthly scale, the precipitation foreshadow is as follows:
June – 99% of LPA (LPA for June = 165.3 mm)
● 70% chance of normal
● 10% chance of above normal
● 20% chance of below normal
July – 95% of LPA (LPA for July = 280.5 mm)
● 50% chance of normal
● 20% chance of above normal
● 30% chance of below normal
August – 92% of LPA (LPA for August = 254.9 mm)
● 20% chance of normal
● 20% chance of above normal
● 60% chance of below normal
September – 90% of LPA (LPA for September = 167.9 mm)
● 20% chance of normal
● 10% chance of above normal
● 70% chance of below normal
The government and farmers will need to take appropriate measures to mitigate the impact of a weaker monsoon. Skymet’s forecast provides an early indication to the government and farmers to prepare for the upcoming monsoon season.