Private forecaster Skymet Weather has said the country appears to have missed the bus regarding the onset of the monsoon over Kerala, which it had earlier predicted would unfold on May 26, with a model error of +/-3 days. There is no sign of the seasonal weather system approaching the coast as of Thursday, said GP Sharma, President, Meteorology and Climate at Skymet Weather.

Progress of monsoon hit

“Things don’t look good,” Sharma told BusinessLine and pointed to the negative Indian Ocean Dipole (IOD) as the immediate culprit. It has evolved faster than thought and is potentially playing spoilsport at this phase of the progress of monsoon from Sri Lanka. “If we had to declare the onset today, it should have been raining on the previous two days along with the designated stations in Kerala. This has not happened along expected lines,” he explained.

On course, says IMD

Meanwhile, national forecasting agency India Meteorological Department (IMD) said on Thursday morning that the monsoon is on course and conditions are favourable for its further progress of the Arabian Sea arm over some parts of South-West Arabian Sea (farther away from the Kerala coast and Lakshadweep); some more parts of South-East Arabian Sea (nearer to Kerala coast and covering Lakshadweep); the Maldives and the Comorin area by Friday (tomorrow).

Transiting waypoints

These are the usual but critical waypoints that monsoon transits on its journey towards the Kerala coast. On the Bay side (Bay of Bengal arm), the IMD sees the monsoon making progress over the South and East-Central Bay of Bengal and some parts of North-East Bay of Bengal by Friday. According to Sharma of Skymet, both these arms of the monsoon have to act in tandem to precipitate the onset. It also requires a helpful circulation (vortex) to form over either the seas to anchor the flows. But there is no sign of any such system forming anytime soon, he said.

‘Models have failed us’

“Even the models which we depend on to predict the onset seem to have failed us. The negative IOD is having a larger than life impact early into the season even as a helpful La Nina in the Equatorial Pacific is receding gradually. What happens in our backyard in the Indian Ocean has a pronounced effect on the weather than the tele-connection that the Pacific farther away may have had,” Sharma explained.

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