Chennai, Oct 9 (IANS): The Regional Meteorological Centre (RMC) has predicted normal to heavy rains in Tamil Nadu till October 15.
An official of the weather department said that a yellow alert has been issued in Salem, Karur, Tiruchi and Kallakurichu districts while heavy rains have been forecasted in six more districts on October 10.
He said that an orange alert has been issued for Tamil Nadu as well as Kerala, showing the possibility of rainfall of very heavy intensity (11.5 cm-20.4 cm) on October 12, October 13, and October 14.
With the Southwest monsoon rapidly retreating and the Northeast monsoon to arrive by October 15, the weather department said that rainfall is set to steadily increase and cover most parts of the state
In its extended rainfall forecast for two weeks till October 16, the India Meteorological Department (IMD) had forecast that the Northeast monsoon was likely to set in around October 15.
The Regional Meteorological Centre (RMC) said that a low-pressure area over Lakshadweep and adjoining southeast and east-central Arabian Sea, are likely to gain strength as the depression would enhance easterlies and rainfall over the State.
The RMC has predicted that large swathes of the region would be covered with light to moderate rainfall till October 14, adding that more districts of Tamil Nadu would receive heavy rains till October 15.
During the past 24 hours, ending 8.30 a.m. on Wednesday, several interior places and some coastal places received rainfall. Karur received 8 cm of rainfall, which was the heaviest in the state.
The RMC has forecast that Chennai would experience light to moderate rainfall in some areas till Friday.
Typically, the Northeast monsoon begins around October 20, but the RMC stated that it is common for the monsoon to set in nine days before or after this date.
However, the RMC also mentioned that there will likely be a rainfall deficit in the southern districts compared to the northern ones.
However, the central regions of the state are expected to receive abundant rain.
Additionally, the IMD predicted that the southern peninsular region, including Tamil Nadu, Kerala, and Andhra Pradesh, is likely to experience above-normal rainfall during the Northeast monsoon.
The IMD forecast indicates enhanced rainfall in Tamil Nadu during the third and fourth weeks of October.
Tamil Nadu typically receives an average of 44 cm of rainfall during the Northeast monsoon, which extends from October to the end of December.
The IMD also mentioned the possible impact of La Niña, a weather phenomenon that could result in normal or surplus rainfall in the state.
Historically, Tamil Nadu has experienced surplus rainfall 69 per cent of the time during La Niña events, occurring 42 times between 1940 and 2021.
In the years 2010, 2016, and 2023, when La Niña occurred, there was surplus rainfall in 2010 and 2023, but in 2016 the state experienced a rainfall deficit.
The IMD also noted that changing weather dynamics, along with factors such as global warming, are influencing rainfall patterns during both the Southwest and Northeast monsoons.
The department stated that it has improved its forecasting methods and now achieves 85 per cent accuracy in its predictions.
Meanwhile, the Tamil Nadu government is preparing for the monsoon, with district disaster management authorities working closely with district administrations and other departments, including health, police, and fire and rescue services, to plan for potential inundation and flooding due to heavy rains.
Local authorities have been instructed to clean stormwater drains and carry out basic road repairs, including covering pits, to prevent water stagnation and clogging.