Cyclone Amphan is a very intense storm which can wreak large-scale damage, India Meteorological Department Director General M Mohapatra said on Monday.
Amphan has intensified into a super cyclonic storm and is expected to make a landfall on May 20 between the Digha islands in West Bengal and Hatia islands of Bangladesh, Mohapatra said at a press briefing.
It is likely to de-intensify to an extremely severe cyclonic storm when it makes a landfall.
He added that the coastal districts of West Bengal will receive heavy to extremely heavy rainfall on May 19 and 20. These include East Midnapur, South and North 24 Parganas, Howrah, Hooghly and Kolkata in West Bengal.
The storm is also likely to impact the coastal districts of north Odisha, including Jagatsinghpur, Kendrapada, Bhadrak and Balasore.
Meanwhile, the Indian Metrological Department has advised a complete shutdown of shipping and boating activities in parts of West Bengal and Odisha till May 20.
IMD chief Mrutyunjay Mohapatra said, "We have advised a complete shutdown of shipping and boating till May 20."
He added that the weather department has also advised for rerouting or shutting down of rail and road traffic in some parts of the West Bengal and Odisha which the super cyclone is expected to hit.
"The super cyclone is likely to cause extensive damage to 'kuchcha' houses and old structures. Uprooting of trees, telephone poles, palm trees etc is also expected. Ships and large boats can be damaged heavily," Mohapatra said.
The India Meteorological Department forecast said that the storm will lose some of its intensity on the way and slam West Bengal as a very severe cyclonic storm during the landfall between Digha in the state and Hatiya islands in Bangladesh on Wednesday evening. The cyclone will still have a maximum sustained windspeed of 165 to 175 kmph gusting up to 185 kmph, the weatherman said.
Howling winds travelling at a speed of 220 to 230 kmph and gusting to 255 kmph were being witnessed over west-central and adjoining parts of south Bay of Bengal. It is likely to increase further to 230 to 240 kmph and gusting to 265 kmph by Monday night, IMDs Regional Director G K Das said in Kolkata.
Meanwhile, West Bengal Chief Minister Mamata Banerjee on Monday said all precautionary steps, including evacuation of people from coastal areas, have been taken to deal with any eventuality arising out of cyclone Amphan.
Teams of disaster management department, National Disaster Response Force (NDRF) and State Disaster Relief Force (SDRF) have been sent to the vulnerable areas, she said.
"We will be monitoring the situation for cyclone Amphan 24X7. Chief Secretary Rajiva Sinha, Home Secretary Alapan Bandyopadhyay and the secretary of disaster management department will be keeping a close watch on the situation," Banerjee told reporters at the state secretariat.
Prime Minister Narendra Modi also reviewed the situation with Union Home Minister Amit Shah and top government officials in New Delhi.
Also, the National Disaster Response Force (NDRF) has deployed 37 teams in the coastal areas of the two states, its chief S N Pradhan said.
(With input from Agencies)