The Met office on Friday warned of heavy to very heavy rainfall in several south Bengal districts, including Kolkata, as the severe cyclone 'Dana' weakened into a cyclonic storm after completing landfall process in neighbouring Odisha.

The weather office forecast heavy to very heavy rain in Purba Medinipur, North and South 24 Parganas, Kolkata, Howrah, Hooghly, Purulia and Bankura districts on Friday, while extremely heavy rain is likely in Paschim Medinipur and Jhargram districts.

Dana, which has completed the landfall process between Dhamra and Bhitarkanika in neighbouring Odisha this morning, is likely to weaken further into a deep depression by Friday afternoon.

It said that light to moderate rain is likely at many places over south Bengal, with heavy rain at one or two places in Purba and Paschim Medinipur and Jhargram districts on Saturday.

Gale wind speed reaching 80 to 90 kmph, gusting to 100 kmph is prevailing in northwest Bay of Bengal and will gradually decrease becoming squally wind speed reaching 40 to 50 kmph, gusting to 60 kmph from Friday evening, the Met said.

It advised fishermen not to venture into the sea along and off Odisha and West Bengal coasts till Saturday morning.

Kolkata recorded 100.3 mm rainfall in 24 hours till 11.30 am on Friday, the Met said.

Diamond Harbour and Sagar Island in South 24 Parganas received 93 mm and 89.6 mm rainfall respectively in 24 hours till 8.30 am on Friday, the Met office said.

The other places in south Bengal which received significant amount of rainfall during the same period are Kalaikunda (90.6 mm), Haldia (80 mm), Jhargram (66.6 mm), Medinipur town (52 mm) and Digha (37 mm), the weather office said.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.