Many a times it is given to note that during SWM period the cause of rain in Tamilnadu is referred to as convective. It is convective activity due to warm air advection during these rainy days. Most of the time Warm Air Advection [WAA] is inferred from radar products. Moist warm air from WEST after crossing western ghat gives rainfall from WEST to EAST in Tamilnadu. To day [11.08.2011 / 2200 hrs IST] it is evident from satellite imagery and DWR products that moist air is advecting and it may rain at S-SW /NW parts of Villupuram & Puducherry to night.