Climate Change

Cyclone Gulab likely to make landfall September 26

Cyclone Gulab quickly intensified from a low pressure area on the morning of September 24 to a cyclone by the evening of September 25

 
By Akshit Sangomla
Published: Sunday 26 September 2021
Cyclone Gulab on September 26. Photo: Earth Null School
Cyclone Gulab on September 26. Photo: Earth Null School Cyclone Gulab on September 26. Photo: Earth Null School

Cyclone Gulab, the first cyclone post-monsoon, formed in the Bay of Bengal on the evening of September 25, 2021. It may make landfall along the south Odisha and northern Andhra Pradesh coasts by the evening of September 26, according to the India Meteorological Department (IMD).

The likely area of landfall is between Kalingapatnam in Andhra Pradesh and Gopalpur in Odisha.

 

The cyclone quickly intensified from a low-pressure area on the morning of September 24 to a cyclone by the evening of September 25. The IMD has not forecasted further intensification of the system.

But it did mention that many of the forecasting models did not agree on the further intensification of the system, leaving this aspect uncertain. The models mostly agree on the path of the cyclone.

The IMD has generated a yellow alert message for the regions in the path of the cyclone. Heavy to extremely heavy rainfall is predicted for coastal Odisha and Andhra Pradesh on September 26 and September 27.

Heavy rainfall can also be expected in Telangana, Chattisgarh on these days. As the remnant of the cyclone moves across the Indian landmass, other states may also receive heavy rainfall in the subsequent days.

IMD expects the peak wind speeds of the cyclone to be around 95 km / hr, which would be mainly experienced around the areas where the landfall will occur on September 26.

These areas include Srikakulam, Vizianagaram and Visakhapatnam districts of Andhra Pradesh and Ganjam and Gajapati districts of Odisha.

During landfall, the tidal waves may increase in height by up to 0.5 metre and cause inundation in the low-lying coastal areas of Srikakulam, Vizianagaram and Ganjam districts.

The IMD warns of damage to infrastructure, agricultural fields such as rice, banana and papaya in the affected districts and flooding of rivers, which in turn may lead to landslides.

The cyclone comes after four back-to-back low pressure systems formed in the Bay of Bengal from the end of August, throughout the month of September.

These moved in a general westward-north westward direction from the eastern coastal states towards central India and eventually to western and north western India.

These late rain-bearing systems caused heavy rainfall in many eastern, central and southern states. Some of the states like Odisha and West Bengal experienced intense flooding.

One of these systems intensified into a deep depression, which is one level of intensification less than a cyclone.

Between September 1 and 14, the following Indian states received higher-than-normal rainfall, according to data from The Weather Channel, a website operated by IBM:

Odisha (252.9 mm; 100 per cent above its average), Chhattisgarh (168.7 mm, 34 per cent above average), Telangana (155.2 mm, 102 per cent above average), Maharashtra (199.3 mm, 117 per cent above average), Goa (396 mm, 147 per cent above average), Gujarat (212.4 mm, 222 per cent above average) and Rajasthan (94.5 mm, 110 per cent above average)

Many of the same states had been suffering from drought like conditions before these unexpected spells of rainfall 

Despite the rainfall on September 25, Odisha still had an overall deficit in rainfall of 11 per cent and Gujarat still had a deficit of 12 per cent.

The continuous low pressure systems and now the cyclone have also ensured the delayed withdrawal of the south west monsoon season in 2021.

The IMD predicts that the monsoon winds may start withdrawing by the first week of October which would almost three weeks later than normal date of September 17. This would be the eleventh year in a row when the monsoon withdrawal would take place later than normal.

The possible emergence of a weak La Nina phenomenon in the equatorial Pacific Ocean in the coming months may be a possible reason behind the late September rainfall and the delayed withdrawal of the monsoon.

La Nina is the cooling phase of the El Nino Southern Oscillation phenomenon in the equatorial Pacific Ocean and generally causes an increase in rainfall over the Indian subcontinent.

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