A Bay system that is gaining strength is expected to bring heavy rain to Calcutta, most likely between Sunday morning and Monday morning, the Met office said.
“Yesterday’s low pressure area over northwest Bay of Bengal and adjoining north Odisha-West Bengal coasts now lies as a well-marked low pressure area over the same region at 8.30am on July 4. It is very likely to move west-northwestward across north Odisha and north Chhattisgarh during the next three days,” said a Met bulletin issued on Saturday afternoon.
“The seasonal trough at mean sea level now runs from southwest Rajasthan to the centre of the well-marked low pressure area across Madhya Pradesh, north Chhattisgarh, and north Odisha. Under the influence of the above system, heavy to very heavy rainfall (7-20cm) is very likely in some districts of south Bengal till July 6,” the bulletin added.
On Sunday, “very heavy rain” is likely in West Midnapore, Jhargram and Purulia, while “heavy rain” is expected in South 24 Parganas, Howrah, Hooghly, Calcutta, East Midnapore, Bankura and West Burdwan.
On Monday, heavy rain is likely in Purulia, West Burdwan, Birbhum and Murshidabad in south Bengal. Light to moderate rain and thundershowers are expected elsewhere.
This is the first Bay system of the monsoon season, said a Met official. The Bay usually sees around a dozen such systems between June and September. “Most of them form in July and August, though June also sees a couple on average. This time, there was none,” said an official.
Large parts of north and central India have so far recorded a rain deficit this monsoon. Weather scientists have linked to the absence of Bay systems.
Calcutta, however, saw one of its wettest Junes in recent years, driven largely by localised thunderstorms.
“The current system will have more impact in Odisha than in Bengal. But Bengal will still receive widespread rain along with light gusty winds,” said the Met official in Alipore.
On Saturday, conditions remained largely overcast, though rainfall was minimal, limited mostly to light drizzle in patches.