West Pacific Ocean and Bay of Bengal (BoB) have both swung in to action generating weather systems affecting the respective regions. Some of the typhoons or tropical cyclones of West Pacific travel across East Asian countries like Vietnam, Laos, Cambodia and Thailand to enter BoB from Myanmar frontiers as weak remnants.
These left overs of the tropical storms do revive to become monsoon low or depression in the BoB and activate monsoon surge. However, the bleak side of these typhoons is to suppress the monsoon activity while rolling over Philippines Sea or South China Sea, heading for mainland China, Taiwan and Japan.
Even the recurving typhoons over this area remaining all along over the ocean without hitting landmass influence the weather pattern over the Indian Sub Continent. Typhoon season in the West Pacific runs parallel with Southwest Monsoon of Indian sub continent. Actually, the Pacific has no seasonal boundaries, though most of tropical cyclones form between May and October.
The 1st named storm of 2021 ‘ Dujuan’ developed rather early on 16thFeb. The season’s 1sttyphoon, Surigae, also appeared a little ahead of schedule on 16th April. It went on to become 1st super typhoon of the year and also the strongest tropical cyclone in 2021 so far.
Surigae was also the most powerful tropical cyclone on record for the month of April in the Northern Hemisphere. Another typhoon ‘Champi’ formed nearly after 2 months on 21st June which sailed over the ocean without impacting any landmass.
Presently, typhoon ‘In-Fa’ has formed in the South China Sea, which is centered about 350km southwest of Kadena (Okinawa), an airbase of Japan. In-Fa is a Cat-I equivalent hurricane and still intensifying. The typhoon is likely to skirt and spare Taiwan a direct hit and head for mainland China striking Hangzhou and Shanghai in the wee hours on 26thJuly .
Prior to this, another tropical storm ‘Cempaka’ had formed on 17thJuly which threatened Hongkong. However, it steered away and headed for Hainan province and later moving across Gulf of Tonkin battered Zhanjiang, Nanning and Guangzhou.
This storm followed a weird track, nearly orbiting Gulf of Tonkin and pouring extremely heavy rains, flooding that pocket of China causing casualties. It is still lying as a tropical depression in that area. Another tropical cyclone is in the making over South China Sea, presently marked as ‘Invest 90W’.
A low pressure formed over BoB on 22nd July, the 2nd weather system of the month and third of the season 2021. It became well marked on 23rd but falls short of intensifying further. Yet another low pressure is likely to form over Northwest Bay on 26th/27th July and this may also become well marked but remain short of a depression. Nearly half way through the season, Indian Seas have not seen even a single depression or deep depression.
Persistent stormy activity over the Philippines Sea and South China Sea is possibly deterring intensification of monsoon systems over BoB. These typhoons are very powerful systems influencing the wind flow to thousands of kilometer, precluding formation or intensification of lows and depressions in the Indian Seas.
After the 3rd low pressure area in the last week of July over BoB, there are no signs of another system coming up over that area. Possibly, cyclogenesis over BoB will wait for the clearance of cyclones over the West Pacific and 1st monsoon system of August will have to wait in the wings at least beyond first week of the month.