The Met Office forecast light to moderate rain or thundershowers and heavy falls over the next 24 hours commencing 6pm on Tuesday.
In a regular bulletin, the Bangladesh Meteorological Department (BMD) said light to moderate rain or thunder showers accompanied by temporary gusty/squally wind is likely to occur at most places over Khulna, Barishal and Chattogram divisions.
The BMD also predicted rain at many places over Dhaka & Rajshahi divisions and at one or two places over Rangpur, Mymensingh and Sylhet divisions with moderately heavy to heavy falls at places over Khulna, Barishal & Chattogram divisions.
The low over North Bay and adjoining area intensified into a well-marked low over North Bay and adjoining coastal areas of Bangladesh, forecast stated.
The axis of monsoon trough runs through Rajasthan, Uttar Pradesh, Bihar, West Bengal, the center of the well-marked low and thence northeastwards to Assam across Southern part of Bangladesh, it mentioned.
Monsoon is active over southern part, fairly active over northern part of Bangladesh and strong over North Bay, it added.
Day temperature may fall by (1-2)°C and night temperature may fall slightly over the country.