The Bangladesh Meteorological Department (BMD) has issued a weather alert for eleven regions across the country, forecasting the onset of Nor’westers (Kalbaishakhi storms) and thunderstorms. According to a special weather bulletin released on the afternoon of Friday, 22 May, these regions are expected to experience wind speeds of up to 60 kilometres per hour (kph) before 1:00 AM. In response to the deteriorating atmospheric conditions, river ports within these jurisdictions have been advised to hoist Inland Riverine Warning Signal Number 1.
Regional Storm Forecast and Wind Velocities
The meteorological office indicated that temporary gusty or squally winds, originating from the west or north-west, are likely to sweep over the specified areas. The intensity of these winds is projected to fluctuate between 45 and 60 kph. These storms are frequently accompanied by heavy rain, lightning, and thunder.
The following table outlines the specific regions under alert and the nature of the warnings issued:
| Region Category | Affected Administrative Areas | Forecasted Wind Speed | Warning Signal |
| Northern | Rangpur, Rajshahi, Bogura, Pabna | 45–60 kph | Signal No. 1 |
| Western | Kushtia, Jashore | 45–60 kph | Signal No. 1 |
| Central/East | Mymensingh, Sylhet | 45–60 kph | Signal No. 1 |
| Southern | Barishal, Noakhali, Chattogram | 45–60 kph | Signal No. 1 |
Synoptic Weather Conditions and Five-Day Outlook
In its broader synoptic analysis, the BMD provided a 120-hour (five-day) outlook starting from 9:00 AM on Friday. The current meteorological data reveals that a trough of low pressure is currently positioned over West Bengal, extending its influence towards the North Bay of Bengal. This atmospheric configuration is a primary driver for the seasonal storm activity observed during this period.
Under the influence of this low-pressure system, the weather forecast for the 24-hour period following 9:00 AM Friday includes:
Widespread Precipitation: Most areas within the Rangpur, Mymensingh, and Sylhet divisions are expected to witness rain or thunderstorms.
Scattered Showers: Several parts of the Rajshahi, Dhaka, and Chattogram divisions will likely experience temporary gusty winds and lightning alongside light to moderate rainfall.
Isolated Activity: A few locations in the Khulna and Barishal divisions may see sporadic rainfall or thunderstorms.
Rainfall Intensity Warnings
The department further cautioned that the precipitation would not be uniform across all affected regions. There is a specific forecast for moderately heavy to heavy rainfall in certain parts of the Rangpur, Mymensingh, Dhaka, and Sylhet divisions.
The Inland Riverine Warning Signal Number 1 serves as a cautionary notice for river craft, indicating that a region is threatened by squally weather. Vessels are advised to navigate with extreme caution or seek shelter as the storm progresses. The BMD continues to monitor the trough’s movement and will provide updates as the system evolves over the next five days.