Yesterday saw a quiet day in North Tamil Nadu particularly north of Pondicherry Latitude while rains continued for the second straight day in many places over South Tamil Nadu. Parts of Kanyakumari, Ramanathapuram, Tirunelveli, Thootukudi districts moderate rains while places in Virudhunagar, Madurai, Theni, Sivaganga & Dindigul districts recorded light rains in South TN. In the central parts of the state light to moderate rains were recorded in Trichy, Karur, Perambalur & Ariyalur districts while isolated rains were recorded in the West Interior parts of TN with Dharapuram in Tiruppur dt recording about 24 mm until 5:30 in the morning
With the circulation just straddling the Southern parts of Sri Lanka and the adjoining waters of Comorin Sea places in North Tamil Nadu has been seeing the drier winds from Northeast rather than the moisture filled Easterly winds from Bay of Bengal. This is the reason for the relatively dry conditions that has been prevailing over Chennai & surrounding areas for the last 24 hours or so.
Models indicate similar conditions to prevail today as well with the best chance for Chennai lies in possible convergence of Northeast & Easterly winds bringing instability triggered thunderstorms similar to Sunday Night. There is a faint chance this convergence could happen today around midnight today which could possibly trigger thunderstorms in the region. As of now best chance for Chennai will lie from such thunderstorms until the overall dynamics change under the influence of a fresh low that is likely to emerge out of a disturbance coming in from South China Sea.
In the meanwhile places south of Pondicherry / Delta stand a good chance of another day of possible rains in many places under the influence of the persisting Circulation off Sri Lanka. Models indicating this circulation to move West slowly to give way for the incoming pulse from South China Sea. As long as the circulation persists around Comorin Sea rainfall chance for South TN and some of the interior areas of the state persists.