Another Cloudy day likely, some chance of Rains in Chennai

It is always a tricky thing to estimate rains in Chennai particularly during the Southwest Monsoon time when most rains in Chennai is through convective activity triggered by atmospheric instabilities or by strong sea breeze fronts that interact with remnant moisture travelling across Peninsular India from the West Coast under the  monsoon surge. The last couple of days have seen cloudy conditions dominate Chennai but the rains never materialized even though some of the models were predicting thunderstorms over North Tamil Nadu.

Today is another day when models are divergent about possible rains in Chennai with huge variance in the estimates of how the day could pan out for Chennai.  There is a possibility the rains may not happen also as we have estimated the possible weather synopsis based on our inference.


Let us look at a few factors on why the conditions are good for Rains in Chennai.

  1. The Low Pressure Area that is over Coastal Andhra Pradesh is tilted south and the mid tropospheric circulation is over North TN providing the right support for synoptic rains.
  2. The Lower Level winds are also angled right to create a moisture drag over North Tamil Nadu providing for rainfall prospects over the area
  3. Across all levels right from 1.8 km to about 5 km the moisture availability is quite high which creates conducive conditions for thunderstorm activity with right trigger
  4. Unlike the last few days the CAPE, a factor key for triggering thunderstorms, has shown improvement providing decent prospects for the rains.

Having said this there is a possibility with cloudy skies all day long and sea breeze unlikely to happen today we may not see the trigger activated at all for the rains to happen.  Nevertheless as amateur weather enthusiasts it will be an interesting day to see how events pan out.