The Western Ghats over Tamil Nadu, Kerala & Karnataka has been relatively subdued after the monster spell around Independence Day creating extreme flooding and huge damages to people and places around parts of Tamil Nadu, Kerala & Karnataka. It was possibly a much needed respite from rains to allow the administration & thousands of Volunteers to focus on the relief & rehabilitation efforts.
Despite a low pressure forming in Bay of Bengal subsequently it did not rain much which possibly remains as a question with some of the common people. Two Back to Back Lows during the fist fortnight of August which tilted more south compared to the next set of lows created an angle of trough which was perfectly placed for moist winds to hit against the Western Ghats bringing heavy rains to the Southern parts of the Ghats while the Shahyadris missed out mostly. The current low is also likely to bring heavy rains in isolated places along the Western Ghats due to moisture drag but the angle will possibly ensure the heavier spells possibly stay north of Malnad region unlike the first fortnight of Kerala.
Yesterday saw thunderstorms continue in a few places over Tamil Nadu with even a few southern suburbs of Chennai to witnessing short heavy spell of rains in the evening. Places like Kanchipuram and few areas around Ariyalur / Cuddalore district got moderate thunderstorms. Today looking at the wind charts the chance for places in North Tamil Nadu & adjoining parts of South Andhra Pradesh could witness moderate thunderstorm activity later in the evening as there could be a possible convergence of different wind masses triggered by the Well Marked Low Pressure area off Odisha Coast.
As we mention often the angle of winds matter a lot in weather and in particular for thunderstorms driven rainfall probabilities. Looking at the model wind estimates it appears the best probability falls slightly over North of Chennai but there is always a difference in the eventual event & what model estimates so the chance for Chennai as good as the rest of the places to catch a decent spell of rains in the evening.