Break in Chennai Rains expected as Southwest Monsoon takes center stage

After 3 or 4 days of rains in and around Chennai rains are expected to take a break as Southwest Monsoon sets foot on the Indian Sub Continent officially.  With IMD confirming the Monsoon Onset over Kerala (MOK) it is time to look at the West Cost for sustained rainfall activity as the monsoon magic unfolds slowly around the Indian Sub Continent moving up gradually over the course of the next few weeks covering the entire Indian Sub Continent.


The conditions are perfect for Southwest Monsoon to make further progress today over Karnataka and may be up to Goa under the influence of the strong offshore trough off West Coast & the Upper Air Cyclonic Circulation over Arabian Sea.  This is likely to bring in heavy rains over South Konkan region & Coastal Karnataka particularly around the Uttara Kannada districts.

With yesterday’s rains over many parts of Tamil Nadu, we have had 3 straight days of rains in Chennai city and in some places around the region 4th day in a row.  Chennai has got almost 10 cms rainfall during these three days which is almost twice of the average rainfall for the month of June.  While Chennai received the bulk of rains many places around Chennai received about 4 to 7 cms of rainfall during this period when the Upper Air Cyclonic Circulation off Coastal Andhra held sway over the weather events in the state.


With Southwest Monsoon getting active over West Coast we can expect the off shore trough to hold control over the weather events of Peninsular India.  Some parts of Coastal Karnataka & Konkan region is likely to receive heavy rains today under the influence of this trough & aided by the UAC as well.  During times when the off shore trough is strong lesser remnant moisture migrates across the interiors of Peninsular India leading to slowing down of the thunderstorms in the interiors & East Coast.  We could see the effect of the trough starting today with rains slowing down and being restricted to extremely isolated places in Tamil Nadu.


While last night’s thunderstorms could possibly keep the temperatures under check we will start to see the Westerlies take dominance with sultry weather set to return for Chennai with weak sea breeze setting the pattern making for uncomfortable evenings in the days to come.