Cyclone Re-emergence

Subject – Geography

Context – Cyclone Gulab could give rise to another cyclone

Concept –

India has a bi-annual cyclone season that occurs between March to May and October to December. But on rare occasions, cyclones do occur in June and September months.
Cyclones are less common during the June to September monsoon season, as there are limited or almost no favourable conditions for cyclogenesis due to strong monsoon currents. This is also the period when the wind shear — that is, the difference between wind speeds at lower and upper atmospheric levels — is very high. As a result, clouds do not grow vertically and monsoon depressions often fail to intensify into cyclones.
However, this year, Cyclone Gulab developed in the Bay of Bengal and later made landfall close to Kalingapatanam in Andhra Pradesh.
So it can be stated that this year, the cyclone season commenced earlier than usual. The last time a cyclone developed in the Bay of Bengal in September was Cyclone Day in 2018.

What favoured formation of Cyclone Gulab?

Three factors — the in-sync phase of Madden Julian Oscillation (MJO), warm sea surface temperatures over the Bay of Bengal, and the formation of a low pressure system on September 24 along lower latitudes — aided cyclogenesis.
The system’s intensification phases between low pressure – well-marked low pressure – depression – deep depression and to finally becoming Cyclone Gulab was rather rapid, even as the system moved closer to the south Odisha – north Andhra Pradesh coast, where it also made landfall.

How common is it for cyclones to re-emerge?

“Climatologically, the frequency of cyclones re-emerging may be less but these are not rare events.”
In the recent past, Vere Severe Cyclone Gaja (November 2018) had formed in the Bay of Bengal. After making a landfall near Tamil Nadu coast, the system moved westwards and re-emerged off central Kerala coast in the Arabian Sea.
With the present warm conditions prevailing over the north Arabian Sea, chances are high that the remnants of Cyclone Gulab could intensify in the coming days. Once it attains the wind speed of cyclone category (68 to 87 kms/hr), the IMD will give it a new name.
“With both the atmospheric and oceanic conditions favouring cyclogenesis, there is strong possibility that the system could re-emerge in the north Arabian Sea close to Gujarat coast.”
Corroborating this probability of system intensification and further westward movement, the chances of another cyclone developing is ‘moderate’, that is, 51 to 75 per cent chances in favour.
“The re-emergent system may not affect India, but IMD has alerted the Indian Ocean countries as the warning is important for fishermen who are already out in the sea”.