Gone are the days when the technology available at the meteorological department in Chennai used to predict accurately about the 5 day rain forecast.
On Sunday, 13th of August 2023, the technology failed and was unable to predict the sudden heavy rains. It is well known that on Sunday many parts of Chennai received heavy rains suddenly and 7 to 10cm of rainfall was recorded. The RMC or Regional meteorological Centre has explained that climate change plays a huge role and it has a significant impact on the weather change. It added that the model could not predict the exact weather pattern.
There was an increase in the rainfall activity in districts like Chennai, Tiruvallur and Kancheepuram etc due to the change in trough winds over the sea. The weather dept predicted that there would be light to moderate rains in few districts with the chances of heavy rains in few places.
Mr. P. Senthamarai Kannan,director of area cyclone centre, RMC, Chennai explained that moderate rains were predicted in Chennai and its neighbouring districts etc. He hinted that the model would not be effective in predicting rainfall patterns. He spoke about how when a system was formed over the sea then the areas where it would rain would be forecasted. The presence of trough wind would usually lead to heavy rains over the sea but the shifting of trough towards left increased the rainfall activity over Chennai, Tiruvallur districts on Sunday evening.
To predict the prevailing atmospheric conditions over the sea, the met dept uses models. No device would be available for accurate prediction of rains. This was also brought out by Mr. Senthamarai Kannan. To predict the weather conditions, 4 radars function round the clock. These 4 radars cover the weather data across Tamil Nadu. In the last few years, the weather models have increased and they have been providing accurate weather forecasts.
It is noteworthy that in the last decade there has been an advancement in the equipment used to predict weather conditions and both hourly as well as monthly forecasts have been provided. Apart from this, the met dept was able to state the impact of cyclones or depression in TN.
To understand the system over the sea better, 3D forecasts have been available for the public. In Chennai these days, there are many changes in the weather conditions and the Chennai Corporation tracks rainfall patterns through many devices, weather websites and by independent weather bloggers etc.