IMD puts a red warning on four Odisha districts as a Bay low sits off the coast

The India Meteorological Department said a low-pressure area formed over the northwest Bay of Bengal and the adjoining West Bengal-north Odisha coasts at 5:30 a.m. on Saturday and was still there at 8:30 a.m. The associated cyclonic circulation reaches 7.6 kilometres above mean sea level. IMD expects the system to become more marked and to move west-northwest across north Odisha and Gangetic West Bengal in the next 48 hours.

A special bulletin from the Bhubaneswar centre at 1:30 p.m. put a red warning on Mayurbhanj, Baleshwar, Bhadrak and Kendrapada for Saturday night into Sunday: heavy to very heavy rain at a few places and extremely heavy rain at one or two places. Other coastal and interior districts sit on heavy-rain alerts, including Jajpur, Cuttack, Sundergarh, Jharsuguda, Bargarh, Sambalpur, Deogarh, Angul, Dhenkanal, Kalahandi, Puri and Nayagarh. The department has spoken of rain through 4 September.

In the 24 hours to 8:30 a.m. Saturday, Bangiriposi in Mayurbhanj recorded 16 centimetres and Chandanpur 10 centimetres. Those numbers arrived before the low had fully organised. The monsoon trough at sea level now runs through Amritsar, Najibabad, Hardoi, Sultanpur, Daltonganj and Purnea to the centre of the low, then southeast into the east-central Bay.

Odisha is already in a second flood wave. Officials say more than 67,000 people in three districts have been affected. State teams have been told to prepare for waterlogging in northern and coastal belts. Ports have signals up. Hooghly (Kolkata and Haldia) hoisted local cautionary signal number 3, with a sectional signal at Sagar Island. Sri Vijayapuram in the Andamans is on the same cautionary number. Seas in the north Andaman Sea are moderate to rough, occasionally very rough, with southwesterly winds 20 to 25 knots, gusting to 30.

A low off north Odisha in late August is not rare. A low off north Odisha while three districts are already flooded is a stacking problem. Embankments that held the first wave will take a second load. Mayurbhanj's 16-centimetre reading is a local cell. Extremely heavy rain on a red warning is a different scale.

IMD's language is careful: "more marked," "west-northwestwards," "next 48 hours." That path takes the rain across the same districts that already have people in relief camps. District collectors will treat the red warning as an instruction to move people before Sunday morning, not after the next 16-centimetre print.

The Bay system is not a cyclone in the bulletin. It is a low with a tall circulation. Tall circulations can dump more rain than their surface label suggests. That is the risk the red warning is trying to name.

Until 4 September the calendar is rain. The variable is whether Mayurbhanj, Baleshwar, Bhadrak and Kendrapada see the extreme end of the forecast or only the heavy end. The 67,000 people already counted will not find that distinction academic.