An Upper Air Circulation presently lying off the Sri Lankan coast and stretching up to 500 hPa levels is expected to trigger rains in South India over the next couple of days. Complete update on the expected rains
There is some diverging outputs from various models on the future events unfolding as far as the potential for development of this UAC. We have tried to be pragmatic in our analysis and have put up this forecast with the next couple of days in mind taking things as they evolve.
Lying just off the Sri Lankan coast in the South West bay the UAC is currently pushing in Moisture at lower levels over Southern Peninsular which is expected to trigger heavy rains over South Tamil Nadu & adjacent areas of Kerala.
The Peninsula is also having a lot of instability in the region thanks to the LWD thats getting created thanks to this UAC and interaction of different air masses over interior areas of Southern Peninsula.
The combination of the above two factors is providing an opportunity for some rains over many places of South India with the bulk of the rains happening over South Tamil Nadu & Kerala.
North Tamil Nadu & adjoining South Interior Karnataka is expected to get benefit from the LWD thats present over the region and possibly some decent spells of rains.
As far as Chennai is concerned there is some chance of rains from Monday night / Tuesday Morning. Its difficult to put a quantum to the rains considering the unclear course the UAC is expected to take. Nevertheless Chennai could certainly benefit out of the current synoptic conditions in the form of lesser day time temperature and possible rainfall at times in a few places.