A cyclonic circulation has been persisting over northeast Bay of Bengal (BoB), next to Arakan Coast (Myanmar) for the last 48 hours. Predominantly, this feature is seen in the middle levels of atmosphere between 10,000’ and 20,000’. Normally, the monsoon systems over BoB originate like this. Start with a cyclonic circulation in the upper air and slowly trickle down to the surface and shape up into a low pressure area. However, BoB is nearly lying dormant with weather activity confined to coastal Myanmar and Bangladesh. Under the influence of this system, Northeast India is witnessing rain and thundershowers for the last couple of days.
This weather system in the BoB is facing double front attack. A powerful storm ‘Biparjoy’ has evolved over East-Central and Southeast Arabian Sea. The cyclone was nearly stationary for sometime and will drift very slowly northward over the open waters of Arabian Sea. The storm is controlling and confining the monsoonal flow around its center. Also, the Western Pacific is hosting a Cat-2 storm in the Philippines Sea ( Guchol) and yet another invest area ( potential cyclone) over South China Sea. While the cyclone Biparjoy is sapping the moisture laden stream over BoB, the typhoon activity over the Pacific is draining and restricting the developments over the region. Resultantly, most parts of BoB are lying inactive, more so the central and western region.
The cyclone in the Arabian Sea is delaying the onset of monsoon over mainland India and stormy activity over the Western Pacific is clogging the streamlined flow of moist winds over BoB. Under these circumstances, not only the onset of monsoon will be mild and meek, but further advancement may also be sluggish. The onset of monsoon is very likely in the next 48 hours. However, the monsoon will struggle hard to penetrate Western Ghats to reach interiors of Peninsular India.