Weather: Depression in Bay set to intensify

An anticipated depression has formed over the North-West Bay of Bengal off the Odisha coast located on Thursday noon about 150 km South-South-East of Paradip; 320 km South-South-West of Sagar Islands (West Bengal); and 470 km South-West of Khepupara (Bangladesh).

It is very likely to intensify into a deep depression, the second of the post-monsoon season, by Friday and move north-northeastwards to cross the West Bengal and adjoining Bangladesh coasts between Sagar Islands and Khepupara over Sundarbans by the same afternoon.

Detailed impact forecast

India Meteorological Department (IMD) said the likely impact from the storm would be felt over the coastal districts of Odisha, West Bengal and Tripura on Thursday; and Assam, Meghalaya, Nagaland, Manipur, Mizoram and Tripura on Friday and Saturday.

The impact would range from flooding of roads, water logging in low lying areas, and closure of underpasses mainly in the urban areas; possibility of landslides in hilly areas in North-East; poor visibility due to heavy rainfall; disruption of traffic; and minor damage to kutcha roads.

Damage to vulnerable structures

Damage may also be expected to vulnerable structures; horticulture and standing crops from inundation, besides threat from squally winds. The landfall of the system may also lead to riverine flooding in some catchments. More details would be available from the Central Water Commission website.

East and North-East India, as a whole, (Andhra Pradesh, Odisha, West Bengal, Assam and Meghalaya) as well as the North-Eastern States were all expected to receive rainfall ranging from light to moderate to heavy to extremely heavy rain on Thursday itself.

Rain belt to move to North-East

The heavy to very heavy to extremely heavy rain belt would shift to the North-Eastern States on Saturday. The sea conditions would range from ‘rough to very rough’ (wave heights of 8-20 ft) in the Bay with high winds. Fishermen have been advised to keep off these sea areas.

The development in the Bay is matched only by the haste with which the erstwhile South-West monsoon is preparing to resume withdrawal from more parts of North India. The withdrawal line is now pushing into Bihar, West Bengal, Jharkhand, Chhattisgarh and Madhya Pradesh.

Monsoon transition to gather pace

The withdrawal process had been stalled due to rain-driving low-pressure areas/depressions crossing land and traversing to West into Peninsular India. But the current low is still sea-bound and tracking elsewhere to the North, leaving the land open for the monsoon transition.

This would happen simultaneously with further withdrawal of the erstwhile South-West monsoon from the Arabian Sea and Peninsular India, with westerly winds being gradually replaced with a regime of seasonal easterlies to north-easterlies by the month-end.