For second straight day Thunderstorms lashed most parts of Chennai with many places recorded 5 to 7 cms of rains in just about an hour or so last evening. Not only did Chennai get good rains many parts of Tamil Nadu also got very good rains including Kanchipuram, Villuppuram dts. The rain rates at some of the IMD AWS touched more than 4 cms of rains in about 30 minutes as intense thunderstorms moved from NNW to SSE across the city. While the IMD observatory at Nungambakkam recorded 77 mm of rains up to 5:30 AM, the observatory at Airport recorded only 24 mm of rains for the same period. Ironically Mangalore which is pretty much at similar latitude on the west coast recorded 66 mm of rains till 5:30 AM today indicating the unique situation currently prevailing over the Indian Sub Continent.
If Chennai got hit by sudden burst of rains yesterday evening, Mumbai in the other coast got hit by a massive cloudburst of a thunderstorm around midnight which dumped nearly 10 cms of rains at most places in an hour & in some cases more than 20 cms rains in a span of 3 hours starting around midnight. On Friday early morning similar storms had hit many parts of Mumbai dumping nearly 20 cms of rains over many areas. Incidentally both these incidents were classic wind stability induced thunderstorms rather than the proper Monsoon rains that we expect at this time of the year.
A dipping trough at 3 kms ASL altitude along with a wind convergence over parts of Peninsular India has been providing conducive conditions for thunderstorms to develop over the region. Partially the weak Upper Air Cyclonic Circulation has been the trigger for this wind convergence to develop & subsequently setting the stage for thunderstorms to form. Today once again weather models are showing a strong wind convergence over Peninsular India which is likely to trigger intense thunderstorms over parts of Peninsular India in the areas of Interior Karnataka, Rayalaseema & adjoining parts of Northwest Tamil Nadu. Few places in these regions are likely to come under intense thunderstorms later in the evening.
With conducive conditions persisting will Chennai score a hattrick day of rains? Things look positive for Chennai to score a hattrick though the rainfall quantum may be slightly lesser than the past couple of days. Nevertheless what models propose, nature disposes, irrespective of the rains another good Sunday of thunderstorms tracking is going to be upon us.