Surge in Lightning Fatalities as Nationwide Nor’wester Alerts Issued

Persistent precipitation and thunderstorms have affected almost every administrative division in Bangladesh, including the capital, Dhaka, for a consecutive week. While the prevailing weather conditions have resulted in a reduction in temperatures across the country, the human cost has been significant. To date, approximately 56 fatalities have been recorded nationwide due to lightning strikes. Despite the dissemination of early warning alerts regarding lightning activity, the mortality rate associated with these atmospheric discharges remains high.

Forty-Eight Hour Nor’wester Warning

On Tuesday, 28 April 2026, at 11:00 am, the Bangladesh Meteorological Department (BMD) issued a formal weather alert effective for the subsequent 48 hours. The notification warns of impending Nor’westers (locally known as Kalbaishakhi storms) expected to sweep across the divisions of Rangpur, Rajshahi, Mymensingh, Dhaka, Khulna, Barisal, Chittagong, and Sylhet.

These storms are projected to originate from the West or North-West with wind speeds ranging between 60 and 80 kilometres per hour, accompanied by frequent lightning and thunderbolts. Public interest in meteorological updates has surged significantly, as evidenced by Google Trends, where queries regarding rain and weather conditions have reached the top of search rankings.

Maritime Signals and Temperature Forecasts

Meteorologists have stated that there is currently no immediate threat of a low-pressure system or cyclone forming in the Bay of Bengal within the next ten days. However, due to the presence of high-velocity winds over the sea, the BMD has instructed the maritime ports of Chittagong, Cox’s Bazar, Mongla, and Payra to hoist Local Cautionary Signal Number 3.

Meteorologist Muhammad Abul Kalam Mallick has provided insights into the current and future temperature trends. While the average temperature for April typically resides at 33.2°C, with historical peaks reaching between 36°C and 42°C, the current year has seen a remarkably temperate April. Aside from a single occurrence on 22 April, when the temperature reached 40°C in Rajshahi, the weather has remained relatively mild and devoid of severe heatwaves.

However, Mr Mallick cautioned that temperatures are expected to rise above seasonal norms following the first week of May. This trend of above-average temperatures is projected to continue through June. The intensity of the perceived heat is likely to escalate periodically over the next two months due to high levels of humidity in the air coupled with low wind speeds.

Characteristics and Frequency of Nor’westers

The months of March, April, and May are classified by meteorologists as the pre-monsoon season. Thunderstorms occurring during this period in Bangladesh and West Bengal—accounting for approximately 38% of annual lightning activity—are locally defined as Kalbaishakhi. Mr Mallick clarified that while thunderstorms continue through the monsoon months (June to September), these are not classified as Nor’westers.

Statistical data provided by the BMD indicates the following average frequencies for Nor’westers:

• March: 5 to 6 storms

• April: 9 storms

• May: 13 storms

In 2026, there has been a notable increase in the formation of thunderclouds. More than ten thunderstorms have already been recorded, exceeding the seasonal average for April. Meteorologists anticipate that from Wednesday, there will be an increase in thundercloud formation in the Rajshahi and Khulna divisions, potentially leading to significant storm damage.

Outlook for May and Cyclonic Activity

Regarding the possibility of cyclones in May—a month historically prone to such events—Mr Mallick indicated that one or two low-pressure systems may develop. There is a possibility that one of these systems could intensify into a depression, deep depression, or a full cyclone.

Scientifically, it remains challenging to predict the exact timing and location of a Nor’wester several days in advance, as these storms often form within a window of just a few hours. Following the current spell of rain, the frequency of precipitation is expected to decline, making way for higher temperatures and increased discomfort due to atmospheric moisture. Currently, most parts of Dhaka, Mymensingh, Khulna, Barisal, Chittagong, and Sylhet, along with scattered areas in Rangpur and Rajshahi, remain under the threat of temporary gusty winds and moderate rainfall.