Tamil Nadu to get four more weather radars in next few years: IMD

Tamil Nadu is set to get four more weather radars in the next few years. The State government plans to invest in radar network with technical support of India Meteorological Department (IMD), said Mrutyunjay Mohapatra, IMD Director General, here on Thursday.

Speaking on the sidelines of the Northeast monsoon seasonal outlook forum hosted jointly by IMD and the State government, he said the IMD would establish new radars at Tiruchi, Kanniyakumari, Yercaud, and Ramanathapuram to strengthen the observation network. Similarly, automatic rain gauges and automatic weather stations are being installed with IMD technical support, and the data generated would help assess hazards at the village level with accurate prediction. The forecast accuracy would further improve by 10% in the next three years.

Noting that the forecast accuracy has increased since 2021, he said IMD is now providing spatial probability forecast, indicating areas likely to get above or below average rainfall.

Heavy rainfall warning accuracy has improved by 40-50% in the past decade. Lightning and thunderstorms warning accuracy in nowcast is now 91%. Prediction of tropical cyclones, their landfall, and time has improved to almost nil error in recent years and reduced the loss of lives. Heatwave prediction accuracy stood at 88%.

Mr. Mohapatra said Northeast monsoon this year is likely to set in between October 15 and October 21 and Southwest monsoon may withdraw completely by October 15. On the relationship between El-Nino and rainfall over Tamil Nadu, he said the strong relationship observed before 2000, when strong El-Nino conditions were associated with good rainfall, had weakened over the last two decades. The State could receive normal rainfall during strong El-Nino years, he said.

Overall, the State is expected to get normal monsoon rainfall this year and the northern districts would experience normal to below normal rainfall. During El-Nino years, cyclones tend to have lower frequency and intensity, and a shorter track. However, cyclone can form over southeast Bay of Bengal and move west-northwestwards, he added.

This year, there is a high probability of systems moving towards Tamil Nadu, Puducherry, south Andhra Pradesh, and Sri Lanka coast. However, weather models do not provide forecasts of cyclone genesis frequency or intensity in the long-range forecast. Such cyclone forecasts are given two weeks in advance, he said.