New Delhi, June 2: A western Pacific typhoon named Mawar, moving near the Philippines on Saturday and sucking moisture and wind currents towards itself, is contributing to the delay in the monsoon’s arrival over Kerala, weather scientists have said.
The scientists said the monsoon was expected to touch Kerala, its first zone of contact with mainland India each year, by June 5, four days after the normal date of onset. They added that the delay would not have any bearing on the rainfall performance during the four-month monsoon season.
The India Meteorological Department (IMD) had two weeks ago predicted that the monsoon would touch Kerala on June 1, with a prediction error margin of four days. But over the past week, the monsoon line has remained static over the southern Bay of Bengal after moving over the Andaman and Nicobar Islands on May 26.
“There is no link between a delay in the monsoon’s onset over Kerala and subsequent rainfall performance,” said IMD director-general Laxman Singh Rathore.
“But we expect wind-flow patterns to change over the next two days and push the monsoon currents over the southern Arabian Sea. It may reach Kerala by June 5.”
Scientists said that Mawar, a western Pacific tropical storm that was upgraded today into a typhoon with wind speeds exceeding 108kmph, had been “dragging” the wind flow towards itself, preventing any strong flow into the southern Arabian Sea.
“Mawar is expected to move north towards Japan,” Sivanand Pai, a senior meteorologist at the IMD, Pune, told The Telegraph.
“As that happens, we expect the flow from the Indian Ocean to detach itself from the typhoon. After the detachment, we expect the monsoon flow to strengthen.”
The IMD’s weather forecast for today said that conditions were favourable for a further advance of the monsoon into some parts of the southeast Arabian Sea, parts of the Maldives and over the southwest Bay of Bengal in the next 48 hours.
In April, the IMD had said that this year’s monsoon was likely to be normal or slightly below normal, with a 71 per cent probability that the total rainfall from June through September would be anywhere between 104 per cent and 90 per cent of the long-term average.
But scientists say there is some uncertainty over the monsoon’s performance because of anticipated changes in sea-surface temperatures in the Pacific Ocean, which have been known to influence the behaviour of India’s monsoon.
Some predictions indicate that the eastern Pacific Ocean sea-surface temperatures may warm to 0.5 degrees Celsius above normal during August and September — a phenomenon called El Nino that has been linked in the past to poor rainfall performance in India.
“But every El Nino has a different bearing on the monsoon. It is not a uniform effect, and there are always other factors that also influence the monsoon,” Rathore said.
The IMD plans to issue an updated long-range monsoon forecast in June.