The northeast monsoon this year may be below normal in the southern parts of Tamil Nadu. However, western and northern parts of the State are likely to have normal rainfall, according to the Meteorological Department.
This was part of the climate outlook for the season (October-December) in South Asia, which was released during the 17th session of the the South Asian Climate Outlook Forum held online on Monday. The outlook was jointly prepared by experts of the National Meteorological and Hydrological Services in nine countries and several regional and global experts from organisations, such as the World Meteorological Organisation.
Citing the outlook, S. Balachandran, Deputy Director General of Meteorology, Chennai, said the southern region below Cuddalore is likely to have below normal rainfall during the upcoming monsoon. Weather models indicate that easterlies, which usher in the monsoon, may set in over the southern peninsula around October 14 or 15. Normally, the northeast monsoon sets in over the State around October 20. On average, the State receives around 44 cm of rainfall during this period.
Noting that the forum discussed prevailing and emerging global climatic conditions to arrive at the statement, Mr. Balachandran said the global weather parameters — La Nina and Indian Ocean Dipole — were not favourable for monsoon rainfall this year. The prevailing weak La Nina and neutral IOD are likely to continue through the monsoon.
Thunderstorms to continue
On the thunderstorms experienced in some parts of the city on Monday, Mr. Balachandran said they were triggered by an upper air circulation at the lower level of the atmosphere and convective activity. Scattered rainfall over the State is likely to continue for two days and districts like Salem and Nilgiris may see heavy rain in one or two places.
While areas such as T. Nagar and Palavakkam experienced light rain, the city weather stations did not record rainfall.
As the southwest monsoon is retreating from some parts such as Rajasthan and Punjab, thunderstorm activity may continue. Chennai may experience thundershowers till Wednesday, officials said.
Meanwhile, the Meteorological Department signed a memorandum of understanding with the National Institute of Ocean Technology to set up the city’s second weather radar at Pallikaranai on Monday.
