Couple of days back many places in Kerala & parts of South Tamil Nadu saw fairly intense thunderstorm activity as the west to east moving CCKW (Convectionally coupled Kelvin Wave) enhanced the effect of wind instability triggering the Veppasalanam thunderstorms. On 6th April many places in Ernakulam, Kottayam & adjacent Idukki districts saw 3 / 4 cms of rains fall in just an hour as thunderstorms lashed these places during the evening hours. Similarly parts of Kanyakumari, Tenkasi & Tirunelveli district has been seeing thunderstorms over the past couple of days while even a few coastal places have been seeing early morning spell of rains influenced by Easterlies.
With the CCKW still over Indian Ocean, now seen over Bay of Bengal, along with the Upper Air Cyclonic Circulation currently seen over the South Bay off Sri Lanka conditions look ripe for an active spell of thunderstorms over the next couple of days. Weather models indicate the current circulation is likely to remain almost stationary as it attempts to descend to surface level and become a Low Pressure Area. This circulation is likely to continue to the wind instability over Peninsular India for Veppaslanam thunderstorms to get triggered during the afternoon / evening hours.
Today weather models indicate widespread thunderstorm activity over parts of South Tamil Nadu & adjoining areas of Kerala. Few places in Kerala are likely to see intense thunderstorms as the presence of CCKW along with abundant moisture pushed into Peninsular India by the circulation off the coast of Sri Lanka will make it high combustible conditions for thunderstorms to explode along the Western Ghats. Along with places in Kerala few places in Pollachi, Tiruppur, Dindigul, Theni, Virudhunagar, Tenkasi, Tirunelveli & Kanyakumari district may see intense spell of rains triggered through moisture trapped by the Ghats.
While today the heavier rains could be along the Western Ghats, fairly widespread rains may happen over South TN and parts of West Interior Tamil Nadu. Over the next few days until possibly middle of next week we can see more places in Tamil Nadu get a spell or two of rains which is likely to bring some respite from the summer conditions. With some luck coastal places in North Tamil Nadu also could benefit from some light to moderate spell of rains.