Agency Reports
Cyclone Gulab resurrects as Cyclone Shaheen over Arabian Sea, to move away from India
NEW DELHI: A low-pressure area defied odds of unfavourable wind shear and moderate heat energy to intensify into a cyclonic storm over the Bay of Bengal last weekend.
Now, it has morphed into yet another cyclone over the Arabian Sea. This is an extremely rare occurrence as most cyclones in this region dissipate fast and do not survive the length from Odisha to Gujarat.
Cyclone Gulab’s arrival before the monsoon’s withdrawal ensured that it stayed alive longer than usual while pouring bountiful rains across the central belt of India.
On Thursday morning, the remnants of Cyclone Gulab emerged into the Arabian Sea, started gaining strength, and concentrated into a depression. The last time such an event occurred was in 2018 when Cyclone Gaja crossed a rather small distance of Tamil Nadu and Kerala to pass from the Bay of Bengal to the Arabian Sea.
On Friday, the system intensified into Cyclonic Storm ‘Shaheen’ as it moved away from the Indian coast. As of Friday, October 1, 5.30 am, the fresh cyclone was 400 km away from Devbhoomi Dwarka in Gujarat.
“The sea-surface temperature (SST) is not too high (28-29°C); wind shear is moderate; the Madden-Julian Oscillation is also not very favourable. So, what is the likely reason for the re-intensification? The only thing that is aiding intensification is the monsoon low-level jet, bringing copious amounts of moisture from the Central Arabian Sea. Coupled with moderate SST and moderate wind shear has allowed re-intensification,” explains Dr Sridhar Balasubramanian, an Associate Professor at IIT Bombay.
The RSMC, New Delhi, also agrees that a favourable environment of warm, moist air and low vertical wind shear is aiding the gradual intensification of Cyclone Shaheen. It is likely to gain more strength and intensify into a Severe Cyclonic Storm by Saturday morning, making it even more potent than the original system, Cyclone Gulab, over the Bay of Bengal.
As it continues to move west-northwestwards across the North Arabian Sea, it is likely to skirt along the coasts of Pakistan and Iran and move towards the Gulf of Oman, says India Meteorological Department (IMD). As it interacts with the coastal regions of Pakistan and Makran in Iran, it is likely to start losing strength on Saturday.
Some model outputs suggest that the system could cross the Makran coast as a cyclonic storm, while others agree it would re-curve and move towards the Oman coast.
While there is no significant threat to India anymore, Cyclone Shaheen may bring heavy rains and strong winds across the southern coastal provinces of Pakistan and Iran.
IMD forecast squally wind speed reaching 40-50 kmph gusting to 60 kmph and rough to very rough sea conditions along and off north Gujarat coast till Friday evening.
An unexpected intensification, followed by swift movement and torrential downpour across the central belt of India—Cyclone Gulab’s dynamics have been a rare display of the resilience of monsoon low-pressure systems.
The cyclone brought substantial rainfall across west and central India, with multiple weather stations registering extremely heavy rainfall of over 200 mm within 24 hours between September 26 to 30.
As a result, September 2021 has turned into the second-rainiest September since 1993 and reduced the monsoon rainfall deficit from -9% at the beginning of the month to -1% at the end.
‘Shaheen’ is a common name across the middle-east, which means ‘Royal white falcon’. Qatar proposed this name! Similarly, the same system that hit the east coast of India on September 26 was named Cyclone Gulab as per the proposal from Pakistan. Cyclone Shaheen is the eighth name to be used from the new list of North Indian Ocean cyclone names that started in 2020. Shaheen is the fourth cyclone of 2021 over the North Indian Ocean and is expected to be relatively mild compared to the first two—Tauktae and Yaas.