Unfavorable MJO may keep a check on Rains

Weather Update
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கெடுப்பதூஉம் கெட்டார்க்குச் சார்வாய்மற் றாங்கே
எடுப்பதூஉம் எல்லாம் மழை

Wrote Thiruvalluvar indicating how Rains often come at the right time when the most needy are desperately looking for it. But many a times it has also decided to stay away when the time is right. Northeast Monsoon almost came to a dead stop after 2015 Chennai Floods, similarly after the 2018 Kerala floods during mid August Southwest Monsoon vanished from Kerala & Coastal Karnataka bringing a huge relief to people.

This year just as districts like Chennai, Chengalpattu, Villuppuram, Cuddalore & adjoining Pondicherry were wondering if they are going to be the victims like how Delhi Ganesh was in the movie Avvai Shanmughi Northeast Monsoon decided to give a break even if it was originally expected to be a few days. This came as a welcome relief to not only many residents of Chennai but also a lot of farmers who were looking at inundated fields that were taking longer period to drain with each following spell of rains.

It is now more than 10 days since both the IMD observatories at Chennai recorded more than 1 cms of rains in a 24 hour period. As a matter of fact even the accumulated precipitation for the month of December has not touched 10 mm as on date indicating how the rains came to a complete halt. In the meanwhile MJO decided to move into West Pacific after over staying over the Maritime Continent for many weeks. The movement of MJO from Maritime Continent to West Pacific completely changed the monsoon dynamics from active monsoon conditions to weak monsoon conditions.

Even the satellite image shows hardly any convection over & off Peninsular India though there is expected to be an Easterly wave impact over South Bay with bulk of convection seen to the South & SE of Sri Lanka along the equatorial waters. With ITCZ also staying south of Equator the convection also has decided to stay closer to Equator. Weather models indicate not much change over the next couple of weeks in terms of MJO movement with possibly the scenario of weak MJO getting stuck over West Pacific until year end now looks a firm possibility bringing what could be curtains for NEM21.

Meanwhile we may see some light to moderate rains over a few places in Coastal TN while Chennai & suburbs may see a sudden burst of sharp spell of rains lasting a few minutes in one or two places. Overall the next couple of weeks we are unlikely to see any heavy rains / extreme rains episode.