The India Met Department (IMD) has said that the low-pressure area forming in the North Bay of Bengal by Friday will intensify into a depression, pushing the monsoon into its most aggressive phase.
The depression would move north-northeastwards across West Bengal and Bangladesh coasts. Some models say it would park itself over Bengal and stay there for a day or two.
Heavy rain outlook
The sheer strength of the monsoon needs to be critically assessed for signs of formation of a mid-tropospheric cyclonic circulation off Mumbai-Gujarat, given its typical geographical features and bearing.
Such a system can trigger very heavy to extremely high rainfall over a small area that can lead to intense flooding conditions as were witnessed during 2005 in Mumbai.
On Wednesday, the IMD came out with a special bulletin with an elaborate discussion about what could likely be in store for the West Coast, East India and their hinterland.
Rainfall activity is likely to scale up over Coastal Karnataka, Goa and South Coastal Maharashtra from Thursday onwards with wide spread rainfall activity.
Rough sea warning
Rainfall amounts may vary from heavy (6.5-12.5 cm) to very heavy (12.5-19.5 cm) at isolated places along this stretch. This aggressive phase is expected to continue till Tuesday (June 12). A similar pattern will play out over adjoining North Coastal Maharashtra, including Mumbai, with heavy to very heavy rains with extremely heavy (exceeding 19.5 cm) rainfall at isolated places from Saturday to Tuesday (June 9-12).
As for the adjoining hinterland, heavy to very heavy rainfall at isolated places is forecast over South Interior Maharashtra from Wednesday to Sunday (June 6-10) and also over North Interior Maharashtra (June 9-12).
Sea conditions will be ‘rough’ to ‘very rough’ off the Konkan and Goa coasts as well as off Somalia in East Africa from Friday to Tuesday.
Fishermen are advised not to venture into the seas during this period.
In the East, rainfall will increase over North Odisha, West Bengal, Sikkim, Assam and Meghalaya during Friday to Monday with heavy to very heavy rainfall at isolated places.
Monsoon advance
Squally winds with speeds reaching 40-50 km/hr and gusting to 60 km/hr are likely along and off the West Bengal, Odisha and Bangladesh coasts on Saturday and Sunday.
During the subsequent two days, it might check into more parts of Maharashtra, Telangana and Coastal Andhra Pradesh. From Saturday, it may enter remaining parts of Maharashtra, some parts of Gujarat, southern parts of Madhya Pradesh and Chhattisgarh, Odisha, West Bengal, and remaining parts of the North-East.