Mercury level is likely to surge in Tamil Nadu in June

CHENNAI: As the scorching summer heat is witnessed in the state, the blistering heat is likely to continue in Tamil Nadu especially over the coastal and interior districts till June. The mercury level is expected to record around 40 degree Celsius until there is a variation over the sea.

Meanwhile, the southwest monsoon is likely to commence on June 4, and there is less chance for intense rainfall for the state, unlike last year. A few isolated places might experience mild showers along with thunderstorm activity in the mid of June.

After the recent cyclonic storm, Mocha formed over the southeast Bay of Bengal and made landfall, the wind flow pattern changed towards Tamil Nadu, and dry in moisture. The state experiences northerly – westerly wind that dominates the sea breeze to the land, that leads to surge in the maximum temperature and sultry conditions in Chennai and its suburbs, interior districts including Vellore, Salem, Karur, and Madurai during the summer season.

"The surge in maximum temperature will continue for the next few days due to change in the wind pattern, and delay in sea breeze in the coastal districts of Tamil Nadu. The mercury level is expected to be around 39 degree Celsius to 40 degree Celsius. Since, the sea breeze delayed in the noon, Chennai and its outskirts recorded over 40 degree Celsius, if there is any change in the wind pattern, increase in moisture level, or cyclonic circulation over the sea the temperature might drop, " said Dr S Balachandran, Deputy Director-General of Meteorology of Regional Meteorological Centre (RMC), Chennai.

At present, north-south trough runs from southeast Madhya Pradesh to south Tamil Nadu across Vidarbha, cyclonic circulation over Telangana, Rayalaseema, north Tamil Nadu at 0.9 km above mean sea level. So, north interior districts of Tamil Nadu such as Namakkal, Salem, Dharmapuri, and Perambalur are likely to witness convective activity – moderate rain for the next few days.

Chennai's Meenambakkam was recorded as the hottest city in Tamil Nadu twice in May month with 42.7 degree Celsius (May 16) and 41.6 degree Celsius (May 27). Even Nungambakkam weather station continues to record around 40 degree Celsius for the past few days. "The state is closer to Andhra Pradesh, the hot wind gets pushed towards Tamil Nadu, so after Vellore, now Chennai becomes the hottest city in the state. The maximum temperature is likely to further increase and cross 40 degree Celsius, " said Tamil Nadu weatherman Pradeep John.

Meanwhile, the southwest monsoon in Kerala is expected to onset on June 4, and it is likely to be normal and only convective rainfall would occur for Tamil Nadu this year, stated the meteorological department.

The SW monsoon 2022 was favorable for Tamil Nadu, as the state received intense rainfall compared to the northeast monsoon last year. Even the Madden-Julian Oscillation (MJO) played a major role during the SW monsoon, and there were more depressions formed over the sea. At least 12 depressions and two cyclones (Chithran and Mandous) were formed in 2022.

Whereas in northeast monsoon 2022, the northern districts of Tamil Nadu witnessed dry weather. And the southern coastal districts including Thoothukudi, Ramanathapuram, and delta districts received less than normal rainfall. Similarly, the southwest monsoon this year is likely to be normal in Kerala, and only isolated areas would receive mild showers.

"After the onset of the SW monsoon, the maximum temperature will be normal and slightly above normal till mid of June month. When there is a change in wind pattern and an increase in moisture level it would subsequently decrease. Usually, the rain for Tamil Nadu in southwest monsoon is below than normal, and the showers we receive are mostly convective type except Western Ghats districts, " opined P Senthamarai Kannan, director of area cyclone warning center, RMC.