An upper level wave instrumental for the boost of monsoon over India is now in the process of moving out towards the South China Sea/West Pacific.
But it has already left behind enough fuel over the Arabian Sea and the Bay of Bengal for the monsoon to thrive for the rest of June.
Latest update from the Australian Bureau of Meteorology said that a helpful Madden-Julian Oscillation (MJO) wave was active over the Indian Ocean region over last week.
The wave travels periodically in the higher levels of the atmosphere but contributes to generating rain-carrying clouds at the ground level.
The movement of the wave could not be captured effectively due to the overarching influence of El Nino over the region and related atmospheric features.
But on hindsight, the Australian Bureau was able to chart the track of the MJO wave, which is now located over central Indian Ocean and the Maritime Continent (Indonesia, et al).
This is what the Bureau has to say: “The MJO maintained a moderate to strong signal as it moved over the Indian Ocean last week.”
Monsoon progress
“During this period, the monsoon progressed from southern to central India, delivering average to above-average rainfall to much of the subcontinent.
By contrast, the Philippines and much of South-East Asia saw generally suppressed convection (process of cloud-building and rain).
The focus of convection has now moved to the central Indian Ocean and equatorial parts of the Maritime Continent.”
While the monsoon has been in good shape over the Arabian Sea, its Bay of Bengal arm has lagged evidence in the skewed alignment of the northern limit of the monsoon.
While the Arabian Sea arm has reached ahead of time in central India, the Bay arm is wallowing over Northeast India at a time when it should have reached Uttar Pradesh.
‘Low’ likely
The Bay is now expected to catch up, taking advantage of the MJO. Models are pointing to the likelihood of a low-pressure area forming soon there.
A ‘low’ helps carry rain-bearing clouds from the sea into land as it moves in a west-northwest direction from where it takes shape.
India Met Department has picked up an upper air cyclonic circulation over west-central Bay of Bengal off north Andhra Pradesh-south Odisha coasts this morning.
This is exactly where global models have been pointing to as the likely area of formation of the ‘low'.
The behaviour of the cyclonic circulation is being watched; all it needs is to descend to the lower levels of the atmosphere to set up the ‘low.’