Rain recorded across India in July-Aug currently stands at 585mm and is expected to cross 595mm in the next two days, which will be around 11% higher than the long period average (535.4mm).This will be close to or higher than 596.1mm recorded in 2019, the wettest July-Aug in the 30 years.
This follows better-than-expected rains in the country in Aug, which came on the heels of a 9% surplus in July. As of Aug 29, average rainfall across India during the month was 16% above normal. IMD had forecast Aug rains to be in normal range (94-106% of LPA).
La Nina, earlier slated for Aug, may now arrive only by Nov
Rainfall in Aug has been beyond expectations. Weather models were predicting a 10 to14-day weak phase during the month. While rains in central India did see a dip for around two weeks, north and south India continued to receive good rainfall during this period,” said M Rajeevan, veteran meteorologist and former secretary in the earth sciences ministry.
July and Aug are the rainiest months in the country, accounting for nearly 62% of total rainfall in the June-Sept monsoon season and usually, the monsoon doesn’t perform well across both months. Last year, for instance, the monsoon was 13% above normal in July but failed in Aug, when the rain deficit was as high as 36%.
Rajeevan said active MJO conditions aided the monsoon in Aug. MJO — Madden Julian Oscillation — is a pulse of stormy weather that moves eastwards along the equator, typically returning to the same spot every one to three months. MJO’s presence in the Indian Ocean usually enhances monsoon rainfall in India. Significantly, MJO had aided the monsoon in July as well.
Meanwhile, the latest forecast by US agencies said that La Nina conditions, which were earlier expected to set in around Aug, may do so only by Nov. It’s expected to be weak and transitory, the forecast added. La Nina, a cooling of ocean waters in central and eastern equatorial Pacific, is another major weather condition that favours monsoon rainfall in India.
“Ocean temperatures in the Pacific haven’t reached La Nina thresholds but the region remains cooler than usual and this has positively impacted the monsoon in Aug,” Rajeevan said.
In a forecast released Thursday, IMD said conditions are likely to remain good for monsoon over the next two weeks.
Cyclone likely in Arabian Sea, the first in Aug since 1976
In a rare occurrence, the deep depression currently over Saurashtra and Kutch that has been causing heavy rainfall in Gujarat for the past four-five days, is set to cross into the Arabian Sea and intensify into a cyclone by Friday, IMD said.
Since 1891, only three cyclones have developed in Arabian Sea in the month of Aug, the last of which was in 1976. While the storm is expected to move westwards along the coast of Pakistan and Iran, winds gusting up to 75kmph are likely along and off the Gujarat coast from Thursday to Saturday, the agency said.
Simultaneously, a low-pressure system in the Bay of Bengal is likely to develop into a depression and move towards north Andhra Pradesh-south Odisha in the next two days, IMD warned.