Climate Change

Weakening of Tej in Arabian Sea might have strengthened Hamoon in Bay of Bengal: IMD Expert

Hamoon expected to make landfall between Khepupara and Chattogram in Bangladesh  

By Jayanta Basu
Published: Tuesday 24 October 2023
A Windy map showing 'Hamoon'__

The weakening of Cyclone Tej in the Arabian Sea might have strengthened its counterpart Cyclone Hamoon across Peninsular India in the Bay of Bengal, a senior India Meteorological Department (IMD) official told Down To Earth (DTE) on October 24, as Hamoon looked all set to become a ‘very severe cyclonic storm’.

It is after 5 years that the marginal seas of the Indian Ocean are together witnessing cyclones. The last time such a phenomenon took place was in 2018, when Cyclones Luban and Titli formed over the Arabian Sea and Bay of Bengal respectively.

“Multiple factors seem to be working in tandem to make Hamoon stronger than earlier predicted, including the shifting of Tej in the Arabian Sea. In a twin cyclonic system — here Tej and Hamoon — often one gets stronger. In this case, Tej was the stronger one. But as it has already made landfall, shifted and is gradually weakening, Hamoon now seems to be picking up,” Sanjib Banerjee, deputy director general, IMD Kolkata, told DTE on the morning of October 24.

“We earlier predicted that Hamoon would intensify into a cyclonic storm and was likely to make landfall as a deep depression. The latest prediction is that the cyclone will turn into a very severe cyclone for a few hours and then enter Bangladesh as a cyclonic storm, as scheduled, on the afternoon of October 25,” Banerjee said.

As a system moves away from the coast; the influx of warm air gets reduced. Consequently, the system gets stronger, he said.

“It may also be the case that the sea surface temperature of the region where it is now located is more than the earlier position, further contributing to the intensification,” added Banerjee. 

On October 24 morning, Cyclone Hamoon lay over the northwest Bay of Bengal, having intensified more than what was predicted till the night of October 23.

IMD issued its national bulletin No. 29 at 8 am on October 24 morning, based on findings till 5.30 am. It read:

Cyclonic Storm “Hamoon” (pronounced as Hamoon) …is very likely to intensify further into a very severe cyclonic storm for a few hours during next 6 hours.

IMD further predicted: “Thereafter, it is likely to weaken gradually while moving northeastwards and cross the Bangladesh coast between Khepupara and Chittagong (Chattogram) around the evening of October 25 as a cyclonic storm with wind speeds of 65 to 75 kmph gusting to 85 kmph.”

The earlier national bulletin No. 28 predicted that Hamoon would intensify “into a severe cyclonic storm and … very likely move nearly north-northeastwards and cross the Bangladesh coast between Khepupara and Chittagong around noon of October 25 as a Deep Depression.”

According to IMD, the maximum sustained wind speed of the deep depression was in the range of 52 kmph to 61 kmph. 

The coastal districts of West Bengal — South 24 Parganas, North 24 Parganas and Purba Medinipur — may witness heavy rain on October 24 at a few places. They will also be impacted by wind speeds of 40 to 50 kmph, gusting to 60 kmph. Howrah, Hooghly and Kolkata districts are likely to receive light to moderate rain on October 24.  

“We do not expect the Sundarbans to be much affected, apart from some rain and strong winds as the system is recurving away from the West Bengal coast,” said an IMD source.

The system has quickened and will make landfall earlier than expected, sources told DTE.

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