The Bangladesh Meteorological Department has reported a shift in weather conditions across the country following a period of intense heat, attributing the change to the formation of a low-pressure system over the Bay of Bengal. According to the agency, this system is expected to increase rainfall activity nationwide, with a particular risk of heavy to very heavy showers in several northern and north-eastern divisions.
In a warning issued at 11:00 am on Monday (11 May), the Bangladesh Meteorological Department stated that convective cloud formation is likely to intensify within the country, and that the prevailing conditions may persist for several days. From the evening of Wednesday (13 May) and over the subsequent 72 hours until 16 May, districts within the Rangpur, Mymensingh, and Sylhet divisions may experience heavy rainfall ranging between 44 and 88 millimetres in 24 hours, with isolated areas likely to record very heavy precipitation.
The department also cautioned that very heavy rainfall could lead to temporary waterlogging in low-lying areas of the Sylhet division. The low-pressure area has formed over the south-western Bay of Bengal, near the northern coast of Sri Lanka and adjacent regions, while an extension of a western low-pressure system remains positioned over West Bengal and surrounding areas.
According to meteorological assessments, rainfall activity began on Sunday in several parts of the country under the influence of convective cloud systems. Rainfall intensity is expected to increase from Tuesday, particularly in the Rangpur division, with Mymensingh, Sylhet, and Dhaka divisions also likely to experience intermittent showers.
Meteorologist Dr Omar Faruq stated that most parts of the country are likely to experience varying levels of rainfall throughout the week, with the northern and north-eastern regions expected to receive comparatively heavier precipitation. He further noted that clearer assessments regarding the strength of the low-pressure system would be available within 24 hours, including whether it may intensify further and affect coastal regions.
Rainfall classification
| Category | Rainfall (24 hours) | Description |
|---|---|---|
| Moderate | Below 44 mm | Light to moderate showers |
| Heavy | 44–88 mm | Significant rainfall activity |
| Very Heavy | Above 88 mm | Risk of flooding and waterlogging |
Under standard meteorological definitions in Bangladesh, rainfall between 44 and 88 millimetres within 24 hours is classified as heavy, while precipitation exceeding 88 millimetres is considered very heavy.
Weather forecast overview (next 120 hours)
| Day | Affected divisions | Expected conditions |
|---|---|---|
| Monday | All divisions (isolated areas) | Light to moderate rain with thunderstorms and gusty winds |
| Tuesday | Rangpur, Rajshahi, Mymensingh, Sylhet | Localised thunderstorms; mostly dry elsewhere |
| Wednesday | Multiple divisions nationwide | Light to moderate rain; heavy rain in northern regions |
| Thursday | Widespread across country | Increased rainfall; heavy to very heavy in north and northeast |
| Friday (15 May) | Mymensingh, Sylhet and others | Scattered showers; heavy rainfall possible locally |
In the preceding 24 hours until 6:00 am Monday, the highest recorded rainfall was 64 millimetres in Nikli, Kishoreganj. During the same period, the highest temperature was recorded at Ramgati in Lakshmipur, reaching 36 degrees Celsius.
The Bangladesh Meteorological Department continues to monitor the system closely and will issue further updates as necessary, particularly regarding any intensification of the low-pressure area over the Bay of Bengal.