Heavy rains are all set to lash the state of Kerala and parts of Karnataka. While the entire state of Kerala will see rains, the coastal regions will be the main beneficiaries of heavy rains in Karnataka.
The reason for these rains is the east west trough running from Andhra up to Konkan across Telangana. The trough also has embedded circulation over Karnataka and south Maharashtra.
Thus, rains will be moderate over both Coastal Karnataka and Kerala. Tomorrow and the day after, i.e. September 28 and 29, the spread will increase, and rains will become more intense. In fact, heavy rains are quite likely over both regions. September 30th onward, rain will start to reduce.