A fresh spell of thunderstorms is likely in Bengal, the Met office warned on Thursday.

“In the presence of favourable meteorological conditions and strong moisture incursion from the Bay of Bengal, enhanced thunderstorm activity is very likely over the districts of Bengal during the next three days,” said a bulletin.

Calcutta is likely to get at least one spell of thunderstorm between Friday and Saturday, said a Met official.

On Monday, a powerful Nor’wester — the season’s first — struck Calcutta. It unleashed a peak wind speed of 72kmph, recorded at Alipore.

“A fresh western disturbance is emerging over northwest India. There is more than one trough affecting Bengal. A combination of factors will lead to a significant rise in moisture incursion in Bengal,” said a Met official.

Light to moderate rain is likely across south Bengal on Friday, the Met office has said.

Thunderstorms with strong gusts of wind and hailstorms are likely in Purulia, Jhargram, Bankura, West Midnapore, East Burdwan, West Burdwan, Birbhum, Hooghly and Howrah. The wind speed may reach 70kmph in these areas.

Thunderstorms, lightning, and gusty winds (reaching speeds of 50-60 kmph) are likely in the remaining areas, including Calcutta.

According to the forecast, on Saturday, the intensity of the thunderstorms is likely to be higher in districts like Murshidabad, Nadia, North 24-Parganas, East Burdwan, Hooghly, Howrah and West Midnapore.

On Sunday, light rain/thundershower is likely in North and South 24-Parganas, Jhargram and East and West Midnapore districts. Dry weather is most likely to prevail over the remaining districts in south Bengal.

The intensity of the rain is likely to be higher in north Bengal. Very heavy rain is expected in Jalpaiguri and Alipurduar districts. Heavy rain is likely in Darjeeling, Kalimpong and Coochbehar districts.