A low-pressure area is imminent over the north and adjoining central Bay of Bengal, setting the stage for a prolonged period of rainfall across West Bengal over the next seven days, according to the latest weather bulletin.

Just two days ago on September 23, torrential rain had left large parts of the city and several districts waterlogged, damaging hundreds of vehicles, submerging pandals under construction, and soaking clothes, books and household goods in shops and homes.

The system is developing from a persistent upper air cyclonic circulation. It is anticipated to intensify into a depression over the northwest and adjoining west-central Bay of Bengal off the South Odisha-North Andhra Pradesh coasts by September 26. The depression is then very likely to make landfall across the South Odisha-North Andhra Pradesh coasts around the morning of September 27.

For Kolkata, the local forecast for Thursday says the sky will remain partly cloudy, becoming generally cloudy by afternoon or evening, with light to moderate rain or thundershowers likely. The maximum and minimum temperatures are expected to be around 33 degrees Celsius and 27 degrees Celsius. The city is expected to see light to moderate rain or thunderstorms almost every day over the next seven days

Humidity remained high on Wednesday, with 98 percent maximum and 74 percent minimum, while 6.6 mm of rainfall was measured in the last 24 hours until Thursday.

“There is a possibility of lightning strikes in open fields and traffic congestion in urban areas. People have been advised not to take shelter under trees or electric poles and to avoid contact with water bodies during thunderstorms,” the IMD said, warning of the next seven days.

Light to moderate rainfall is very likely to continue at many places across South Bengal for the next seven days through October 1. The most significant weather is expected on September 27: heavy rainfall (7-11 cm) is very likely at isolated places, specifically over South 24 Parganas and Jhargram districts.

The IMD has also placed Kolkata under a yellow alert on Friday, Saturday and Sunday of this week for thunderstorms with lightning and gusty winds of 30-40 kmph.