— Photo: S. Gopakumar

WELCOME RELIEF: A farmer herds ducks as monsoon clouds gather overhead. A scene from rural Thiruvananthapuram on Monday morning.

NEW DELHI: Announcing the onset of the south-west monsoon over Kerala, the India Meteorological Department (IMD) on Monday said that conditions were favourable for further advance of the monsoon. During the next 48 hours, it could cover some more parts of Tamil Nadu and some parts of coastal and south interior Karnataka.

Speaking to The Hindu, a senior IMD official said that it was a typical onset satisfying all the meteorological conditions required for declaring an onset. Among other things, an off-shore trough has developed along the west coast from Kerala to Karnataka, and there was persistent cloudiness over the Arabian Sea and adjoining peninsular region.

The wind, which was flowing till recently in a north-westerly direction, has also not only changed direction into a westerly/north-westerly flow, typical of monsoon, but has become stronger and deeper. In addition, there has been continued widespread rainfall with isolated heavy falls for the last two days over Kerala. "The monsoon has arrived with a bang," he said.

Rapid development

It has been quite a rapid development. Even as late as May 23, there were no signs of an imminent onset, making the IMD issue a press release that its earlier forecast of an onset on May 24 plus or minus three days may not come true because of the development of an anomalous low level circulation over west-central Arabian Sea and persistence of a mid-latitude westerly trough over Indian region. Conditions began to turn around for the better around May 25 and on May 26, IMD in a press release said the monsoon could set in over Kerala on or before May 29.

This is not the first time the monsoon has set in before the normal date. During the last 50 years, the earliest onset over Kerala was in 1960. That year, the monsoon had set in on May 14. Last year too it had set in earlier — on May 26.

Senior IMD officials clarified that the early onset over Kerala did not mean the onset would be earlier in other parts of the country too. Also, there was no one-to-one correspondence between the date of onset over Kerala and the pattern and intensity of rainfall during the course of the four-month monsoon season.

The agency had, on April 19, issued the annual long range forecast, according to which the total rainfall for the season and for the country as a whole would be 95 per cent of the long period average with a model error of plus or minus five per cent. "The forecast stands. It will be updated next month, as already announced," the officials said.

Printer friendly page  
Send this article to Friends by E-Mail