Wednesday’s depression over Bay of Bengal beat predictions and chose to drop anchor around the Head Bay of Bengal (off Kolkata).
It did not move into Bangladesh, but crawled over to coastal West Bengal where it remained practically stationed overnight, the Met Department said.
The US Joint Typhoon Warning Centre had alluded to this probability in its bulletin issued by Wednesday evening.
The depression was located to a region 30 km south-east of Midnapore on Thursday afternoon, but was expected to weaken into a low-pressure area by Friday.
It has thrown up a trough of lower pressure extending from south-east Uttar Pradesh and extending into east-central Bay of Bengal.
Winds blow into the trough and the moisture carried by them will pour down as rain under its footprint. The Met Department has warned of thunder squall at one or two places over Bihar, Jharkhand, north Odisha, West Bengal and Sikkim during the next two days.
SQUALLY WEATHER
These areas fall under the footprint of the trough. Heavy to very heavy rainfall would lash north Odisha, West Bengal, Sikkim, Bihar and Jharkhand.
Squally winds speed reaching 40-50 km/hr and gusting to 60 km/hr would prevail along and off north Odisha and West Bengal coasts until Friday afternoon.
Sea condition will be rough to very rough along and off north Odisha and West Bengal coasts during this period. Fishermen have been advised not to venture into the sea. Outlook from Sunday to Thursday suggested possibility of rain or thundershowers at many places over north eastern States, sub-Himalayan West Bengal, Sikkim and Andaman and Nicobar Islands.
LIKELY ONSET
Rainfall activity is expected to scale up along west coast. This phase could likely witness the onset of monsoon over the Kerala coast. Rain or thundershowers would occur at one or two places over East India and south Peninsular India during this period. On Thursday, a seasonal outlook from the Busan, South Korea-based Asia-Pacific Climate Centre said that India will experience normal to above normal monsoon during both June and July.
There could be a slight setback in August, but that should not undo the overall performance of the monsoon, the agency said.