One of the common comments we get to hear on weather regularly is “It has never been as hot like this before”. Discussions on climate change are now happening on a more regular basis and among common people too. IMD has clear guidelines on heatwave though abnormal heat is often used in a more confusing manner. Merriam Webster explains abnormal as “deviating from normal or average”. In this context it always becomes essential to quantify the abnormal heat that most use regularly. One possible way to quantify this is to compare it with past records. This exercise will allow us to check how big was the abnormality.
Over the last couple of weeks most parts of Tamil Nadu has seen abnormal heat. The daily temperature charts from IMD indicate many stations are recording a couple of degrees above normal. A more detailed analysis though show a clearer picture of the nature of abnormality in these temperatures. Five stations have seen the hottest recorded temperature during this September this year. 12 other stations in Tamil Nadu has recorded Top 10 highest temperatures at least one day this year. Nagapattinam and Madurai has recorded the highest temperature during September in 140 years. Similarly Karaikal has recorded its highest temperature during September in 50 years while Tondi has recorded its highest temperature during September in 75 years.
The abnormal heat seen over most of Tamil Nadu is due to the dry conditions persisting over Peninsular India. Unfortunately weather models indicate these conditions may persist for another week to 10 days before we can see some respite. Sub seasonal forecasts indicate abnormal heat may continue over large parts of TN for most of this week. While some reduction in temperatures is seen next week pockets in South & West TN may continue to see high temperatures. Isolated thunderstorms will gradually start from today / tomorrow over South TN and adjoining delta. Towards the weekend parts of North TN may also see the return of thunderstorms. This gradual revival of thunderstorms in a few days time may be the first step in putting an end card to scorching September 2024. Until then we will have to bear with the heat.
Today also large parts of Tamil Nadu may see day time maximum temperatures stay 2 – 4°C above normal. Isolated pockets in West & South TN may see max temperature anomaly touch 5°C. Similar conditions may persist tomorrow also with some reduction like from Thursday. Chennai and suburbs may continue to see maximum temperature of around 38°C for the next couple of days. It may seem ironical to see the complete post dedicated to temperatures when Northeast Monsoon is just a few weeks away. But sometimes facts are stranger than fiction.