Kolkata weather is likely to remain unsettled today and tomorrow as a weather system over the Bay of Bengal continues to influence conditions across eastern India.

While the system has been widely referred to as Cyclone Arnab, the India Meteorological Department has so far classified it as a deep depression and has not forecast it to become a cyclonic storm.

For Kolkata, however, the immediate concern is the weather impact rather than the system's name or classification.

The city is expected to remain under generally cloudy skies on Wednesday, September 23, with spells of rain or thundershowers during the day.

The IMD's Kolkata-Howrah forecast has also warned of thunderstorms accompanied by lightning and gusty winds reaching 30-40 kmph.

The weather office has forecast a maximum temperature of around 30°C and a minimum of around 24°C in Kolkata on Wednesday.

The city had already recorded rainfall in the preceding 24-hour period, with the IMD's Kolkata station reporting 5 mm of rain up to 8.30 am on Wednesday.

Relative humidity stood at 92 per cent at 8.30 am, indicating the sticky conditions likely to persist through the day.

The rain is expected to remain a feature of the city through the evening, with thunderstorms and lightning possible in parts of Kolkata and neighbouring districts.

A yellow watch for lightning issued for Kolkata, Howrah, North 24 Parganas and South 24 Parganas was in effect Wednesday afternoon, with light to moderate rain and thunderstorms expected in some areas.

Thursday, September 24, could bring another wet spell for Kolkata. The IMD forecast indicates generally cloudy skies with a few spells of rain or thundershowers, while the maximum temperature is expected to remain around 29°C and the minimum around 24°C.

The weather office has also flagged the possibility of heavy rainfall, thunderstorms, lightning and gusty winds of 30-40 kmph.

The wider weather situation is linked to the deep depression over the Bay of Bengal.

According to the latest reports, the system is moving west-northwestwards and is expected to cross the north Andhra Pradesh-south Odisha coast between Visakhapatnam and Gopalpur during Wednesday night and the early hours of Thursday.

Heavy to very heavy rainfall and strong winds are expected in parts of Odisha and Andhra Pradesh.

The system's possible influence on Bengal means residents in Kolkata and adjoining districts could continue to see periods of rain and thunderstorms even as the main system moves towards the Andhra-Odisha coast.

However, Kolkata is not currently forecast to face a direct landfall from the system.

The term Cyclone Arnab also needs some clarification. Arnab is the next name on the North Indian Ocean cyclone naming list, but the current system has not been officially declared a cyclone.

The IMD's present forecast indicates that it is expected to remain a deep depression.

For Kolkata residents, the immediate forecast therefore points to two more unsettled days, with cloudy skies, rain, lightning and gusty winds remaining the key weather concerns.

People travelling during thunderstorms are likely to need extra caution, particularly around waterlogged stretches and exposed areas.