Unusually Active Monsoon Brings Heavy Rainfall to Northwest India: Cyclone Asna to Form Over Arabian Sea

The monsoon has been exceptionally active over northwest India in August, leading to severe rainfall and flooding across the region. Meteorologists predict that this pattern will persist into the first week of September, with extremely heavy rainfall expected in parts of Gujarat until at least Friday.

Severe Flooding in Gujarat Due to Deep Depression

A deep depression over Saurashtra has been the primary cause of the severe flooding in parts of Gujarat. The India Meteorological Department (IMD) reported that this depression is likely to intensify into Cyclone Asna over the northeast Arabian Sea by Friday. Extremely heavy rainfall is expected to continue in isolated areas of Saurashtra and Kutch until Friday, after which it will gradually decrease.

“The deep depression, which has sustained for several days over Saurashtra, will encounter favorable conditions to intensify into a cyclone over the Arabian Sea. It will gain energy from the ocean, refuel, and potentially become Cyclone Asna,” said a senior IMD official. Although rare, it is not unprecedented for a system to emerge over land and develop into a cyclone after moving into the ocean.

Impact on Other Regions: Heavy Rains Across India

In addition to the developments in Gujarat, a low-pressure system over east India has brought heavy rains to the eastern states. Delhi-NCR has also experienced spells of heavy rain due to the monsoon trough near Delhi. The low-pressure system over central and northern Bay of Bengal is likely to cause very heavy to extremely heavy rainfall in Odisha, Coastal Karnataka, Kerala, and Mahe, with heavy rainfall expected in North Coastal Andhra Pradesh, Chhattisgarh, Vidarbha, and Telangana over the next few days.

“Rain will reduce over the next two days over northwest India, but it will pick up again from September 1 when the monsoon trough shifts back to its normal position,” said Mahesh Palawat, Vice President, Climate and Meteorology at Skymet Weather. He also indicated that isolated heavy to very heavy rain is expected in the region on September 2 and 3.

Monsoon Overview: Excess Rainfall Across India

Since June 1, India has recorded 7% excess rainfall, with central India receiving 17% more rain than average, northwest India 2% excess, and Peninsular India 18% excess. However, east and northeast India have seen an 11% rainfall deficiency.

August alone recorded 15.9% excess rainfall across the country, with 31.4% excess over northwest India, 7.2% excess over east and northeast India, 17.2% excess over central India, and a slight deficiency of 1.3% over Peninsular India. Notably, northwest India has seen a 76% excess in rainfall since June 1, though some regions like Jammu and Kashmir, Punjab, Himachal Pradesh, and Haryana have experienced rainfall deficits.

Historical Context: Rare Cyclone Activity in Arabian Sea

The development of cyclonic storms in the Arabian Sea during August is rare. According to the IMD, only three cyclonic storms have developed in this region between 1891 and 2023, occurring in 1976, 1964, and 1944. These storms typically weakened after emerging into the Arabian Sea, but the current conditions indicate a strong possibility of Cyclone Asna intensifying as it moves over the ocean.

IMD Director General M Mohapatra noted last week that the monsoon is in an “extremely active condition” across India, with significant rainfall expected to continue in various regions. He emphasized that the weather systems over Rajasthan and Gangetic West Bengal will further contribute to the heavy rainfall in Gujarat and other parts of the country.