Cyclonic disturbances are seen in North Indian Ocean throughout the year. The disturbances enter the Indian seas – Arabian Sea and Bay of Bengal - and cause tropical weather system like depression, deep depression and storms.
Cyclonic disturbances entering the Bay of Bengal have single maxima and minima i.e. they increase in number from March till September and decrease thereafter, becoming lowest in February. On the other hand, the disturbances in Arabian Sea have double maxima and minima i.e. they increase in number from March to June, decrease in August, peaks again in October to November and sharply decrease in February.
Fifty percent of cyclonic disturbances fizzle out while the rest have the potential of converting into cyclonic storms. The potential cyclonic storms on an average have a life span of 4-6 days.
Cyclone Nilofar
The existing cyclone Nilofar that originated on 23rd October in the Arabian Sea is expected to have a life span of more than 10 days which is climatologically considered a fairly long period for a cyclonic storm. The cyclone is expected to make a landfall on the 1st November and affect the weather till the 2nd November.
Historically Speaking
A cyclonic storm from 14th Oct 1996 – 2nd November 1996 had a life span of 20 days. It is one of the longest duration North Indian Ocean tropical cyclone in the history. It began its journey in the Bay of Bengal on 14th October 1996. It moved westward without much development and hit the eastern Indian coastline on the 18th October. It crossed South Peninsula and emerged into the Arabian Sea on the 20th October. It turned towards north and became a tropical storm on the 22nd October. On the 23rd, it reached the cyclone strength though large vertical wind shear weakened it into a depression on the 26th. The system turned southward and southwestwards and re- strengthened to a tropical storm on the 27th October. The tropical storm continued west –southwestwards until the vertical wind shear weakened it into a depression on the 31st October. It crossed Socotra Island on the 31st October and dissipated on the 22nd, east of Somalia.