Northeast monsoon may set in around Nov 1

CHENNAI: Conditions like low pressure and winds over Bay of Bengal appear favourable, but it remains to be seen if it will be third time lucky for the India Meteorological Department whose experts forecast that the much-awaited northeast monsoon may set in around November 1. Two earlier predictions failed after winds changed direction and due to the absence of a favourable weather system in the Bay of Bengal.

The Regional Meteorological Centre, Chennai, in a statement said, "Conditions are becoming favourable for the commencement of Northeast monsoon rain over Tamil Nadu and Puducherry and adjoining areas of south coastal Andhra Pradesh, Rayalaseema, south interior Karnataka and Kerala around November 1."

This, it says, is because a cyclonic circulation over southwest Bay of Bengal and adjoining Sri Lanka, extending up to 3.1km above mean sea level, has persisted. trough or extended region of low atmospheric pressure in easterlies runs from the cyclonic circulation near Sri Lanka to northwest Bay of Bengal off West Bengal coast across west Central Bay and extends up to 1.5km above mean sea level. Weather experts say the two conditions over Bay of Bengal are likely to bring rainfall to the state by October 31 and it is likely to continue till November 3.

"By October 30 or 31, we can expect rainfall to increase over Tamil Nadu and will continue till November 2 or 3," said Mahesh Palawat, chief meteorologist of private forecating agency Skymet Weather.

After a brief dry spell, the state will experience a wet Diwali as heavy rain is expected from November 5 to 7. "The cyclonic circulation is likely to intensify into a low pressure area by November 4," Palawat said.

Impact of El Nino may bring above normal rainfall this year

While light to moderate rain or thundershowers are likely to occur at isolated places over Tamil Nadu and Puducherry, the IMD has also issued a warning for November 1 and 2, saying heavy rain is likely in isolated places over Tamil Nadu.

For the next 48 hours, RMC Chennai says, “Light rain is likely to occur in some areas. Maximum and minisum temperatures are likely to be around 32 degrees Celsius and 25 degrees Celsius respectively.”

This year, El Nino, a phenomenon in the equatorial Pacific Ocean that leads to warmer oceans, is likely to have an effect, resulting in above normal rainfall this northeast monsoon.