Met Office projects rainfall at around 90 per cent of long-period average
The notional date for monsoon’s arrival in Keralam is June 1. This onset marks the beginning of monsoon period for the Indian landmass
A developing typhoon over the western Pacific drew moisture away from the Arabian Sea and Bay of Bengal, leading to delayed onset of the monsoon
Announcing orange alerts for all districts in Keralam, the Indian Meteorological Department says the southwest monsoon had made landfall in the state. The met department further noted that conditions favour advance of rain-laden winds with more than 15 districts in the western and southern parts of Tamil Nadu bracing for heavy rainfall.
Generally, the notional date for monsoon’s arrival in Keralam is June 1. This onset marks the beginning of monsoon period for the Indian landmass with four months, from June to September, accounting for about 75 per cent of rainfall for the country.
At present, the Met department declares the onset of monsoon as per daily rainfall of 14 stations over Kerala and neighbouring areas along with wind field and Outgoing Longwave Radiation (OLR) over southeast Arabian Sea.
For further advance of monsoon in other regions, sharp increase in rainfall and its characteristic sustenance for a few days and associated changes in the atmospheric circulation features are considered. Monsoon spreads in India by the middle of July.
Notably, the IMD had earlier predicted the monsoon onset over Keralam to take place on May 26. As per reports, meteorologists stated that a developing typhoon over the western Pacific drew moisture away from the Arabian Sea and Bay of Bengal, leading to delayed onset of the monsoon. Also, a cyclonic circulation near the Lakshadweep region delayed the onset.
For the coming monsoon, the IMD has projected rainfall at around 90 per cent of long-period average (LPA). Derived from the period between 1971-2020, the 870 mm is the average rain for the country.
The subdued forecast can be read alongside developing El Nino conditions. El Nino is an ocean-atmospheric phenomenon along the equatorial Pacific Ocean during which the ocean surface along the Pacific is warmer than usual. It is generally associated with a reduced summer monsoon over India.
For context, around 51 per cent of the country's cultivated land relies on rainfall. This accounts for about 40% of agricultural production in a country where farming employs almost half of population for their livelihood. Monsoon, therefore, is essential for irrigation, drinking water, and even electricity generation through hydropower.
