Kolkata, July 26: A well-marked low-pressure area over the Bay of Bengal is set to trigger widespread rainfall across several districts of south Bengal over the next few days, the Regional Meteorological Centre (RMC) in Kolkata said on Sunday.

According to the Met Office, the weather system has developed over the northwest Bay of Bengal under the influence of a cyclonic circulation over south Bengal and adjoining Bangladesh. It is expected to strengthen further over the next two to three days. The active monsoon trough, stretching from Rajasthan through Uttar Pradesh and Jharkhand to the Bay of Bengal coast, is also contributing to the prevailing weather conditions.

While Kolkata is unlikely to witness heavy rainfall, the city may experience intermittent showers accompanied by thunderstorms, lightning and gusty winds of 30-40 kmph on Sunday and Monday. Heavy rain is, however, likely in South 24 Parganas, East Midnapore, West Midnapore, West Burdwan, Jhargram, Purulia and Bankura over the next two days.

Most districts of West Bengal are expected to receive scattered rainfall along with gusty winds, with wind speeds reaching 40-50 kmph in isolated areas. The Met Office has also warned of thunderstorms across south Bengal, while scattered showers are expected to continue from Tuesday onwards.

"The sea remains rough due to the low-pressure area, with winds blowing at 35-45 kmph. Fishermen have been advised not to venture into the sea until Monday. Conditions are expected to improve thereafter," a Met official said.

Rainfall is also expected to continue across north Bengal. Darjeeling is likely to receive heavy rain from Tuesday to Thursday, while Jalpaiguri and Kalimpong are expected to experience heavy rainfall from Monday through Saturday.

Alipurduar and Cooch Behar are also likely to witness spells of heavy rain from Tuesday, prompting the Met Office to issue a yellow alert for these districts. Although North Dinajpur, South Dinajpur and Malda are receiving scattered showers, no weather warnings have been issued for these districts so far.

Kolkata recorded a minimum temperature of 26.5°C on Sunday, 0.2°C below normal. The maximum temperature on Saturday settled at 29.6°C, which was 3°C below the seasonal average.