A fresh low-pressure system may develop over the Bay of Bengal, bringing the possibility of rain and thunderstorms across several parts of Bangladesh, according to the Bangladesh Meteorological Department.
At the same time, mild heatwave conditions are continuing over five districts. The weather office said rainfall in those areas could help ease the heatwave, potentially bringing some relief from the prevailing warm conditions.
The forecast was issued for the period from 5am to 1pm on Thursday (17 September).
According to the latest bulletin, temporary squally winds accompanied by thunderstorms may affect Rangpur, Bogura, Tangail, Mymensingh and Sylhet. Winds from the south-eastern direction may reach speeds of 45 to 60 kilometres per hour in these areas.
In view of the possibility of strong winds and thunderstorms, river ports in the affected areas have been advised to display warning signal No. 1. The warning is particularly relevant for people travelling or working on waterways, where sudden squalls can create hazardous conditions.
The Meteorological Department had also issued a five-day weather forecast from 6pm on Wednesday, highlighting the possibility of rain across a broader area.
Many parts of Rangpur, Mymensingh and Sylhet divisions may experience temporary gusty winds followed by light to moderate rain or thunderstorms. Some areas of Rajshahi, Dhaka, Khulna, Barishal and Chattogram divisions may also receive similar weather.
The forecast also indicates the possibility of moderately heavy rainfall in isolated parts of the country. Rainfall is not expected to be uniform, however, with conditions likely to vary from one region to another.
Meanwhile, mild heatwave conditions are affecting five districts — Dhaka, Faridpur, Rangpur, Jashore and Khulna. The persistence of rainfall in some of these areas could bring down temperatures and reduce the intensity of the heatwave.
The five-day outlook suggests relatively modest fluctuations in temperature rather than any major shift in overall conditions. On the first day, both daytime and night-time temperatures may fall slightly across the country. Temperatures are expected to remain almost unchanged on the second day.
A slight rise in both daytime and night-time temperatures is forecast for the third day. On the fourth day, daytime temperatures may remain nearly unchanged, while night-time temperatures could fall slightly. On the fifth day, daytime temperatures may decline marginally, with little change expected in night-time temperatures.
The combination of thunderstorms, gusty winds and possible heavy rainfall means weather conditions could change quickly in affected areas. People using rivers and other waterways are advised to remain alert when thunderstorms develop, particularly in areas covered by the river-port warning.
The possibility of a new low-pressure system over the Bay of Bengal is also being closely reflected in the broader weather pattern. Low-pressure systems over the bay can contribute to increased moisture and rainfall over Bangladesh, although their eventual development and impact depend on atmospheric conditions.
For the extended five-day period, the Meteorological Department has forecast no significant change in the overall weather pattern. Intermittent rain and thunderstorms may therefore continue in different parts of the country, while temperatures are likely to fluctuate only slightly during the period.
