A low-pressure area on the Bay, poised to become stronger and barrel towards the Andhra-Odisha coastline, is unlikely to have much impact in Bengal.

A Met bulletin said a low-pressure area formed over central and adjoining north Bay of Bengal on Thursday morning.

“It is likely to move west-north-westwards and become more marked over westcentral and adjoining northwest Bay of Bengal by Friday. Thereafter, while moving towards north Andhra Pradesh and adjoining south Odisha coasts, it is likely to intensify into a depression over westcentral and adjoining northwest Bay of Bengal during the subsequent two days,” the bulletin said.

“There is no heavy rain warning for Bengal. Odisha and Andhra Pradesh will bear the brunt of the system,” said a Met official.

Successive systems on the Bay have made this August among the rainiest in recent years, with August 2019 recording more.

According to the Met office, between August 1 and 29, Calcutta got 460.8mm of rain, compared to its quota of 346.2mm. It translates to a surplus of 33 per cent.

“The cumulative rain deficit (calculated from June 1) for Calcutta now stands at eight per cent. It is almost normal. June had ended with a cumulative rain deficit of around 50 per cent in Calcutta. After decent rain in July, the gap was narrowed to around 34 per cent,” said a Met official.

Between June 1 and August 29, the city got 932mm of rain. The quota is 1017mm. One day of formidable rain can put Calcutta in the surplus zone.

Met officials had initially blamed the absence of rain-bearing systems on the Bay of Bengal for the shower shortfall. Monsoon rain in lower Gangetic Bengal is dependent on low-pressure systems over the Bay of Bengal.

This year, between June 1 and the first week of July, there had only been a single low-pressure area (around June 28) on the Bay. But the late July and August saw a flurry of such systems on the Bay and some on the land.

A spell of blinding rain submerged several parts of the city on Saturday afternoon. It was triggered by a low-pressure area over the Bay. Most parts of the city reported significant overnight rain between Sunday and Monday and between Monday and Tuesday.

The next few days are unlikely to see heavy rain. But rain is not ruled out. There is a chance of thundershowers in Calcutta on Saturday, said the Met official.