Southwest Monsoon 2023 has finally arrived over mainland India. The onset of monsoon has been seen over Kerala and some areas of Tamil Nadu along with rest of South Arabian Sea, entire Lakshadweep, rest of Comorin and many parts of Bay of Bengal. One week delay from its scheduled arrival of 01st June was very evident but cyclone Biparjoy stalled it further. This has been the most delayed monsoon in the last 4 years. Earlier, in 2003 and 2019, the southwest monsoon landed over Kerala on 08th June. Before this, the southwest monsoon had arrived on 09th June 1997.
The most delayed monsoon since 1971 happens to be 18th June 1972, and it was a severe drought with a seasonal record shortfall of 24% rainfall. The earliest arrival of this annual event was on 18th May 2004. Coincidentally, that year also ended up with moderate drought registering a seasonal deficit of 14% rainfall. This only goes on to prove that arrival of the monsoon has little correlation with its overall performance. The other factors largely prevail.
Southwest Monsoon 2023 is likely to make a soft start. Initial progress may itself be sluggish. Bursts of monsoon may not be adequate and as desired. Annual felicitating event is facing a double whammy of ‘Biparjoy’ and evolving El Nino. While the powerful cyclone is sapping the moisture of the monsoon stream striking the Kerala coast, the uncanny El Nino is troubling the ‘take off’ of anxiously awaited eccentric events.
The onset of monsoon has stringent criteria, comprising stipulated rainfall, clouds and winds over the demarcated zones. The state of Kerala received decent showers yesterday and the westerly winds are also getting aligned, both in-depth and speed. While OLR (outgoing longwave radiations) struggled to reach the threshold mark of < 200wm~, conditions were favourable for a thick layer of sheet clouds over the desired window in the equatorial region. The stage was set for ushering of southwest monsoon anytime soon.
Monsoon onset is more often expected with a loud and sound bang. In addition to the coastal parts, the interiors of the South Peninsula also expect the monsoon to charge with a fist of fury to announce its arrival. It is unlikely to happen and monsoon may move with a languid pace over the interiors of South India, across the Western Ghats. Undue delay in arrival may also cast a shadow right up to the rain-dependent belt of Maharashtra.