Kolkata: A low-pressure area is likely to form over the Bay of Bengal on Wednesday, bringing very heavy rain in several south Bengal districts over the next few days. The India Meteorological Department (IMD) warned of very heavy showers over the coastal districts of North and South 24 Parganas, Purba and Paschim Medinipur on Wednesday owing to the formation of the system. Heavy rain is expected to occur in these districts, including Jhargram, Bankura, Purulia and Paschim Bardhaman until August 15, according to IMD's forecast. The weather office advised fishermen not to venture into the sea along and off West Bengal and Odisha coasts till August 15 as strong winds reaching speeds of 55 kmph are likely to blow over the region. The north Bengal region, where people have received relief from heavy downpours last week, is likely to receive heavy rain from August 14 to August 17, IMD said. The forecast is for a cloudy sky over Kolkata, with the possibility of light to moderate rain on Tuesday. A very heavy downpour in the northern parts of Kolkata on Monday night inundated several thoroughfares, causing traffic slowdowns in some areas on Tuesday morning also.