Kolkata, Aug 13 : The Met office has forecast heavy rainfall in Kolkata and adjoining areas from Wednesday, following the formation of a low-pressure area over the central Bay of Bengal.

The system is drawing in moisture from the sea and is expected to intensify over the next 48 hours before moving towards the Bengal coast.

Under its influence, heavy to very heavy rain is likely in several south Bengal districts, particularly South 24 Parganas, North 24 Parganas, Howrah, and Hooghly. The Regional Meteorological Centre in Alipore said the monsoon trough currently extends from Jalpaiguri in north Bengal through Haflong in Assam to Manipur.

'The low-pressure area will strengthen in the next 24 hours and bring heavy rain to both south and north Bengal,' a Met department official said.

The sea will remain rough along the Bengal and adjoining Odisha coasts from Wednesday to Saturday, and fishermen have been advised against venturing into deep waters.

Light to moderate rain with thundershowers in Kolkata, Howrah, North and South 24 Parganas, East and West Midnapore, and Jhargram is forecast for Wednesday.

On Thursday, increased rainfall in coastal districts and thunderstorms are likely across south Bengal.

A yellow warning for thunderstorms has been issued for North 24 Parganas, West Midnapore, Purulia, Birbhum, Murshidabad, and Nadia.

In north Bengal, rainfall will persist through the week. Very heavy rain is likely in Darjeeling, Jalpaiguri, Kalimpong, and Alipurduar on Wednesday, with heavy showers continuing in Jalpaiguri and Alipurduar on Thursday.

While no thunderstorm warning is in place for Friday and Saturday, fresh heavy rain is expected from Sunday, particularly in Jalpaiguri, Alipurduar, Cooch Behar, and later in Kalimpong from Monday.

In Kolkata, the minimum temperature on Wednesday was 28.4 degrees Celsius, 1.6 degrees Celsius above normal, while Tuesday's maximum was 34.2 degrees Celsius, 1.8 degrees Celsius above normal.

/IANS