Weather observers regularly explain there is no connection between early onset of Southwest Monsoon and its performance for the season. Many a year despite delayed onset the overall performance of Southwest Monsoon has been relatively good. 2018 seem is currently gasping for breath despite an early fairly strong Monsoon Onset over Kerala.
Since 9th June the Monsoon has stalled over the West Coast while over the other side of the Indian Sub Continent in East India it has remained stationary since 12th June. While stalls are not uncommon with past years showing the monsoon more than makes up the slow progress as we get towards end June / early July. A lot of hopes are pinned on the incoming MJO Wave and the development of the Low Pressure Area in Bay of Bengal to revive Southwest Monsoon progress.
Looking at the Rainfall numbers of Southwest Monsoon 2018 so far it is quiet clear why an immediate revival of momentum is an absolute necessity. As of 22nd June 2018 less than 50% of the districts in the country have seen Normal or better rains (at least 80% of Long term Average Rainfall). Looking at the state classification except for Tamil Nadu rest of all the states in Southern Peninsula has seen more than 2/3rd of the state record normal or better rains with the first 3 weeks of Monsoon gone.
The overall background state has been slowly shifting towards El Nino with the latest weekly Nino 3.4 value at 0.2°C. The atmospheric indicator, SOI, has also started to move towards El Nino state with the last 30 days average at -3.41 & heading towards -7 the threshold level for El Nino episode. In this context it is imperative for Southwest Monsoon to pick up momentum soon or run the risk of another below par season
With models indicating MJO to enter into Indian Ocean with a weak amplitude and long term outlooks indicate below par precipitation estimates over large swathes of the Indian Sub Continent during July it remains to be seen how much momentum can Southwest Monsoon build during the coming days