New Delhi: The India Meteorological Department (IMD) will likely announce on Friday or Saturday the onset of the June-September monsoon, vital for the country’s $885 billion economy, according to Madhavan Rajeevan, director, National Climate Centre, Pune. “The monsoon has set over the Andamans and parts of the Bay of Bengal,” added Rajeevan.
B.P. Yadav, director, IMD, said, “The forecast would be out before Monday.” The monsoon usually arrives over the Andamans around 18 May.
There is usually a gap of two weeks between the monsoon’s arrival in the Andamans and the breaking of another branch of it over the southern state of Kerala.
That state is the starting point for the monsoon over mainland India. In recent years, the rains have arrived over Kerala a week earlier or later than the date forecast by IMD. It’s not only rainfall over Kerala that determines whether the monsoon has begun. Wind speeds at different heights in the atmosphere are crucial to terming showers over it as ‘monsoon’ or ‘pre-monsoon’.
Parts of Kerala have already been registering rainfall. “Winds must blow in the south-westerly direction at about 40-50 km per hour at about 1.5 km above surface level. Then 6 km above the ground, there must be winds from the East,” said Yadav.
Since last year, IMD has been using a new model, whose sole function is to determine the onset of the monsoon over Kerala, Yadav added. Last month, IMD forecast this year’s monsoon showers to be 95% of the long-term average, with a 5% margin of error.
The annual June-September monsoon generates more than 80% of the annual rainfall over the country and is vital for the economy, being the main source of water for agriculture, which generates more than a fifth of the country’s gross domestic product. The rains are also important for traders dealing in food and cash crops as bad rains can cause markets to go into a tizzy.
Reuters contributed to this story.