The last couple of days have seen thunderstorms slowly improve over Tamil Nadu. Yesterday turned out to be a very good day for not only thunderstorms but also areas under monsoon influence with Nagercoil recording more than 8 cms rains along with places in the Ghats over Kanyakumari & Tirunelveli district. Parts of Villuppuram, Salem, Pondicherry, Cuddalore districts along with few places in the Delta recording light to moderate thunderstorm activity last evening.
The remnant circulation from Cyclone Nisarga continues to travel across the breadth of Indian Sub Continent with the Low Pressure prevailing over parts of East India last evening. The convection associated with the circulation is expected to give rains over parts Northeast today. In the meanwhile a fresh disturbance is expected to develop over the Bay which will provide impetus to the Monsoon surge in the coming days. So far the westerlies have been slightly weak which is indicated by the poor numbers in the ghats compared to the plains.
Talking of Westerlies it is always fascinating to watch how small change in the weather dynamics can change things drastically. A couple of days back the winds were from predominantly SW which meant aided by the lofty peaks deflecting them parts of North Tamil Nadu recorded thunderstorms including the suburbs of Chennai like Tiruvallur, Gummidipoondi etc though it was a complete miss for the city area.
Today the winds are leaning towards being proper Westerlies. Peaks like Doddabetta, Anaimudi remain where ever they are but the winds are dynamic. The slight change in wind angle from SW to gentle Westerlies has possibly pushed the thunderstorm zone to the South by about 50 – 100 kms. Yesterday this zone of thunderstorms shifted towards Villuppuram, Tiruvannamalai districts and further drifted East towards the Pondy / Cuddalore coast.
But Crucially the storms have started crossing the Tamil Nadu coast which is indeed a good news for Chennai which is still awaiting its first meaningful spell in more than a month. If storms form at the right place to the West of Chennai we can be fairly sure they will indeed cross the coast providing a good chance for Chennai.