Bay of Bengal is on the verge to script another new normal. The month of March had seen only 5 cyclones in the bay between the years 1900-2021.
However, after a long 20-year hiatus, the southern Bay of Bengal may give birth to a very severe cyclonic storm, as indicated by the sea conditions. The tropical cyclone heat potential is high and ranges between 130-170 kilojoules/cm2 in the southern Bay of Bengal - the region in proximity to Sri Lanka. Moreover, the sea's surface temperature is hovering between 28-30 deg C.
As per IMD and JTWC, a tropical disturbance is being located in the south Bay of Bengal, nearly 889 km to the east southeast of Colombo (Sri Lanka). The high convective area is facing the bump of high vertical wind shear now. It is poorly organised.
For this, the area will develop into a low pressure area (LPA) around ninety-six hours from today. Due to unfavourable conditions, the system will take time get organised. Therefore, no cyclone genesis till March 18.
The Weather Reason
Cyclones in the bay usually take shape when the ITCZ (Inter Tropical Convergence Zone) shifts to the northern hemisphere. (India lies in the northern hemisphere, Australia in the southern).
As per weather observation, ITCZ moves along with the Sun. The Sun god moves to the northern hemisphere by around March 20 only.
As a consequence, the cyclone will develop around that time only, not before that. So, no cyclonegenesis till March 17.
What Is ITCZ?
It is simply a band of heavy rain-bearing clouds, with occasional thunderstorms, encircling the globe near the equator. The solid band of clouds may extend up to many hundreds of miles or at times are broken into smaller line segments.
The model shows by around March 18, a solid band of large convective clouds will dominate the southern bay close to the Andaman and Nicobar Islands. The clouds will organise at a rapid pace and by March 19 and the system will develop into a very severe cyclonic storm, between March 19-20.
As per JTWC, initially, the system will track towards the east, which means away from the Indian coast.
Will It Curve?
A look at the history shows that the place where the probable cyclone's birthplace lies has been the birth ward of five previous cyclones that had originated in the month of March in the Bay of Bengal.
The southern bay close to Sri Lanka and A&N islands had been the birthplace of four cyclones in the bay in the years 1907, 1928, 1994 and 2000.
A look at the cyclonic years reveals that cyclones have originated around the same region at a very irregular span of time. While after first March origin in 1907, it took another two decades to brew up another cyclone.
However, the third cyclone took birth from around the same place after over six-long decades. But the fourth cyclone was brewed in less than a decade.
And as the models indicate, the year 2022 will brew its first cyclones in March after a gap of over two decades.
The time span measures the rarity of cyclones in the month of March. And 2022 happens to be one such rare year, it seems.
Will Odisha Take A Hit?
The cyclonic history discards this possibility. Data shows in 1907, the cyclonic system moved west to hit Sri Lanka. And in 1928, the system however had hit the north Andhra Pradesh coast.
But in the years 1994 and 2000, the systems made landfall in Myanmar.
If the average probability of landfalls will be taken, then there is only a 25 percent chance of the probable system moving close to Odisha and the Andhra coast.
What Models Say?
From INCOIS, NCEP-GFS to ECMWF, the prediction is the system will develop into a very severe cyclone by March 19 and 20. The system is predicted to track a north direction initially, and then veer towards the northeast.
The severe system may make landfall between Chittagong (Bangladesh) and Sittwe in Myanmar on March 23.
A look at the predictions show no rain in Odisha, but the heatwave will become very intense courtesy of the system's influence that drags the winds along with it.