Courtesy monsoon system travelling from Bay of Bengal to inland over eastern states, heavy to very heavy rainfall is likely over the region. The low-pressure area, earlier over northwest Bay of Bengal, has now shifted to southwest Bangladesh and adjoining Gangetic West Bengal. It is likely to move further northwest over West Bengal and neighbouring Jharkhand region. Rainfall is unlikely to be uniform over the region, and heavy falls will stagger from east to west over the next three days between 14th and 16th July 2025.
The well-marked low-pressure area has a cyclonic circulation over Gangetic West Bengal up to higher levels. An east-west axis of the monsoon trough is also passing through this circulation. As the circulation moves deep inland, it is likely to meander over the trijunction of Jharkhand, Bihar, and West Bengal for the next three days between 14th and 16th July. Thereafter, it will move ahead to shift over Uttar Pradesh and Madhya Pradesh.
State of Bihar has been rain deficit by a big margin. The other states, Jharkhand and West Bengal, have recovered from the shortfall earlier incurred during June. The current spell may partially recover the deficiency over Bihar, but the spread of rains will not be large and long enough for any major changes.
The southern half of Bihar state will have a bigger share of rains, and the rest of the region, particularly close to the foothills, may not have adequate rainfall. The places at risk of heavy rains will include Buxar, Rohtas, Bhabua, Aurangabad, Gaya, Navada, Jamui, Banka, Jehanabad, Lakhisarai, Bhagalpur, Patna, Arrah, Samastipur, Khagaria, and Katihar. The northern half of the state may have light to moderate rains.
State of Jharkhand will have the largest coverage of moderate to heavy rainfall. The places at risk will include Garhwa, Palamu, Hazaribagh, Bokaro, Ranchi, Gumla, Khunti, and Jamshedpur. The central parts of Gangetic West Bengal will also have more intense rainfall as compared to the rest of the state. The places to watch out for heavy rains will include Purulia, Bankura, Bardhman, Birbhum, Nadia, and Murshidabad. Southern half of Gangetic West Bengal will witness scattered moderate or light rainfall. Following a short clearance on 18th and 19th July, the state of Bihar will come in for a fresh wave of heavy rains between 20th and 23rd July, with the peak of it between 22nd and 23rd July 2025.
