Depression likely over east-central Bay of Bengal, may intensify monsoon
Monsoon is likely to remain active at least till the end of the month with a well-marked low-pressure area forming over the east-central Bay of Bengal and neighbourhood on Friday, weather officials said.
The system is likely to intensify further into a depression by Friday night and bring widespread and heavy rain to parts of east and central India and then move up to Gujarat. This is the second depression of the season and the second also in September since no depressions formed between June and August.
Normally 5 to 6 depressions form during the monsoon season bringing extensive rainfall to central and west India. Another cyclonic circulation is expected to form around September 28 which will again bring a fresh spell of rain to east and central India, according to forecasts by India Meteorological Department’s Regional Specialized Centre for Tropical Cyclones.
There is only a 2 per cent deficiency in monsoon rain since June 1 with 0 per cent excess over central India; 4 per cent deficiency over northwest India; 9 per cent excess over peninsular India and 11 per cent deficiency over east and northeast India according to the IMD.
The deficiency at the end of August was 9 per cent. The IMD in its forecast on September 1 said owing to above normal rains in September, the overall monsoon rain this year may be in the “lower end of normal category.”
The weather department considers 96 per cent to 104 per cent of the long-period average to be in the “normal” category. The long period average is considered for the period of 1961 to 2010 period and is 88 cm. But considering that widespread rains are likely to continue till the end of the month, total monsoon rainfall may increase further.
A well-marked low-pressure area formed over the east-central Bay of Bengal and neighbourhood on Friday morning and is very likely to become more intense during the next 12 hours. It is likely to move west-northwest wards towards the Odisha coast during the next 48 hours.
A cyclonic circulation is also lying over northeast Madhya Pradesh and adjoining south Uttar Pradesh and a cyclonic circulation is lying over Saurashtra and neighbourhood. A number of systems are forming over the Western Pacific. The remnants of these systems are moving towards the Bay of Bengal leading to the formation of cyclonic circulations and low-pressure areas here.
“A well-marked low-pressure area has already developed over east-central Bay of Bengal (BoB) which is likely to become a depression in the next 12 hours. When it crosses the Odisha coast around Sunday, very heavy rain is expected there and over Chhattisgarh and MP also. Another cyclonic circulation is expected to form around September 28. This is mainly associated with the tropical storm which has just crossed Vietnam. The remnants of the system are moving towards BoB. The favourable position of the Madden Julian Oscillation (MJO) in the east of the Indian Ocean is supporting convective activity and cloud formation over the Bay of Bengal. The remnants from the South China Sea are also moving towards the Bay of Bengal,” explained Sunitha Devi, in charge of cyclones at IMD.
“We can expect widespread rain in the next few days over Odisha, north Andhra Pradesh, Vidarbha, Telangana, Chhattisgarh, Madhya Pradesh followed by Gujarat,” said M Mohapatra, director general of IMD.
The extended range model guidance of IMD is indicating widespread rain over the country till October 7 and patchy rain till October 14. The monsoon is normally expected to commence withdrawal from northwest India from September 16. It is 8 days late already.
“There is no chance of monsoon withdrawal for another week. After this depression moves away, remnants from the Gulf of Thailand may lead to the formation of another low this month. Patchy rain will continue over northwest India including Delhi/NCR. Monsoon may finish with normal rainfall around 99 per cent of LPA,” said Mahesh Palawat, vice president, climate change and meteorology at Skymet Weather. Two depressions and two low-pressure areas formed in September so far as well as more than two cyclonic circulations leading to 30.9 per cent excess rains only in September.