IMD confirms a Bay of Bengal low off north Odisha, with rain warnings into September

The India Meteorological Department said a low-pressure area formed at 5:30 a.m. on Saturday over the northwest Bay of Bengal and the adjoining West Bengal-north Odisha coast. The system grew out of an upper-air cyclonic circulation that had persisted through Friday and extended up to 7.6 kilometres above mean sea level, tilting southwest with height. IMD's Bhubaneswar special bulletin on Friday had already flagged formation around 29 August. Saturday morning made the forecast a surface feature.

Orange warnings for the next 24 hours cover Balasore, Bhadrak, Jagatsinghpur, Keonjhar, Kendrapara and Mayurbhanj for heavy to very heavy rain. Yellow warnings run across a long interior list: Jajpur, Cuttack, Sundargarh, Jharsuguda, Bargarh, Sambalpur, Deogarh, Angul, Dhenkanal, Sonepur, Boudh, Nuapada, Balangir, Kalahandi, Kandhamal, Nabarangpur, Puri, Khordha and Nayagarh. OdishaBytes said colour-coded alerts stretch to the morning of 4 September. For 30 and 31 August the department has a red warning of heavy to very heavy rain at a few places and extremely heavy rain at one or two places in Mayurbhanj.

Manorama Mohanty, director of the Regional Meteorological Centre in Bhubaneswar, told Odisha TV that Mayurbhanj, Keonjhar, Balasore, Bhadrak, Kendrapara and Jagatsinghpur are the heavy-to-very-heavy belt, with thunderstorms and lightning likely for four days. Friday's 24-hour totals ending 8:30 a.m. already showed the northern districts working: Khaira in Balasore 10 centimetres, Kotpad in Koraput 9, Bahalda and Rasagovindapur in Mayurbhanj 9 and 7, Oupada in Balasore 7, Champua in Keonjhar 7.

The monsoon trough at sea level still runs from Amritsar and Dehradun through a separate low over northeast Uttar Pradesh, then Madhupur and Bankura, and on to the northeast Bay. That is why this is not only an Odisha story. Bihar and Bengal sit on the same trough. A coastal low off Balasore feeds the northern interior first and the Mahanadi belt next.

ACWC Kolkata's coastal bulletin kept southwest monsoon moderate over the northwest Bay and listed swell waves of 1.9 to 2.2 metres, period 17 to 21 seconds, from the evening of 28 August through 30 August. Small boats were told to stay in. Beaches and nearshore work were discouraged. That instruction is the part of a low-pressure bulletin that reaches fishermen before it reaches a district collector.

Odisha has already had a wet week. The useful change on Saturday is not the rain. It is the upgrade from a circulation in the upper air to a named low on the surface, with a red box on Mayurbhanj for Sunday and Monday. Collectors in the orange belt will treat that as a flood-watch day on the Baitarani and the Budhabalanga, not as a generic monsoon update.

IMD has not called a depression. The next step on the scale would be a concentrated centre and a drop in pressure. Until that happens the threat is rain totals, lightning and water on roads, not a cyclone track. The dates to watch are 30 and 31 August in Mayurbhanj and the run of warnings through 4 September. Those are calendar facts a district control room can use. The rest is weather language. Saturday morning turned the language into a system on the map.