By Morshadur Rahman

DHAKA, May 7, 2024 (BSS) - After record-breaking heatwave spell, Bangladesh gets respite from prolonged extreme hot weather event as much of the country already has witnessed heavy rainfall with thunderstorms for two consecutive days.

"Severe heatwave is unlikely to sweep over the country . . . but moderate to light heatwave may prevail in southwestern and northwestern regions of the country from mid-May," Omar Faruq, meteorologist of Bangladesh Meteorological Department(BMD), told BSS today.

He said the entire country may witness heavy to very heavy rainfall along with thunderstorms (locally known Kalboishaki) from today and it will continue till May 14 meaning temperature will continue to fall during the period.

On April 26, Bangladesh set all-time heatwave record as the Met Office recorded 24 days of heatwave breaching previous 23 days of heatwave in 2019.

"Twenty-three days of heatwaves were logged during two months of April and May in 2019, which were considered the prolonged heatwaves in the history of the country. But the April alone crossed the grim milestone setting new record of heatwave days," BMD meteorologist Dr Abul Kalam Mallik said.

Explaining the three key indexes of hot weather - - heatwave, severe heatwave and very severe heatwave, the BMD meteorologist said, "We consider temperatures above 36 degrees Celsius for at least two consecutive days as heatwaves while temperatures between 40 degrees and 42 degrees are severe heatwaves and temperature of above 42 degree Celsius is very severe heatwave."

The weather expert said earlier, the western and northern regions -- Khulna, Rajshahi, Rangpur of Bangladesh are considered heatwave-prone areas. Some south-western parts of Barishal division and Dhaka division experienced heatwave, he continued.

"Since the 90s, days of heatwave have been increasing alarmingly in Bangladesh giving a clear signal that the country may face prolonged heatwaves in future . . . Simultaneously heatwaves are spreading across the country," Mallik added.

"Once, heatwaves were confined in the western, northern and central parts of Bangladesh. But this year the entire country witnessing heatwaves. It means weather pattern in Bangladesh has changed drastically extending heatwave coverage areas with its intensity," he added,

According to the BMD collected data, 18 days of heatwave were recorded between April 13 and 14 in Dhaka in 1999, 13 days of heatwave were posted in Dhaka in May in 2004 and 18 days, 19 days, 20 days of heatwave in Jashore in 2014, 2016 and 2017 respectively.

The BMD also added that 13, 10, 17 days and 13 days of heatwave were reported in 2014, 2016, 2019 and 2022 in Rajshahi respectively while 19 and 23 days of heatwave in 2014 and 2019 respectively in Chudanga.

"Khulna and Rajshahi divisions bore the brunt of the heatwave as maximum temperatures above 40 degree Celsius were recorded in most weather stations at the beginning of last month," Bazlur Rashid, meteorologist of Bangladesh Meteorological Department (BMD) said.

"Finally, Khulna division recorded heavy rainfall since yesterday afternoon while another hardest-hit Rajshahi region received little rainfall," the meteorologist forecasted rainfall is likely to occur in Rashahi and Khulna divisions.

Jashore and Chuadanga experienced highest temperature in almost every day since the sweltering heatwave blasted the country since the onset of the summer this year sending mercury as high as nearly 44 degrees Celsius.

The year's highest temperature of 43.8 degrees Celsius was recorded in the southwestern district of Jashore on April 30 while the second highest temperature of 43.7 degrees Celsius was recorded in another south-western district of Chuadanga.

Bazalur said Dhaka city and its adjacent districts recorded a significant amount of rainfall.

He said Chattagram and its adjacent districts received significant amount of rainfall with thunderstorm (locally called Kalboishakhi) since yesterday afternoon and last night.

Supplementing the comments of Bazlur Rashid, BMD meteorologist said when the entire Bangladesh is grappling with a brutal heatwave since April 1 setting all-time record of prolonged heatwave days, much of the country witnessed significant rainfall with thunderstorms.

Rainfall of last two days has brought much needed relief bringing down average temperature by three to four degrees Celsius across the country, Monwar said adding mercury has dipped significantly at some weather stations up to six degrees Celsius meaning very cool weather is prevailing almost entire country.

Unlike previous month of April, residents will get respite from blistering heatwave throughout the month of May as mercury will maintain the tolerable temperature with impact of rainfall and thunderstorms, the BMD meteorologist added.

According to the weather bulletin issued by BMD on May 7, Dhaka city and its adjacent districts recorded a significant amount of rainfall, he said adding, "The Met Office recorded 97mm at Madaripur, 63mm at Gopalganj, "

The country's highest rainfall was recorded in Feni with 130 mm while 118 mm were recorded in Chattogram, 70mm at Swandip, 57mm at Sitakunda, 89mm at Chandpur, 33mm at Bandarban, 75mm at Khulna, 67mm at Sathkhira, 25mm at Jashore, 75 mm at Barishal, 45 at Patuakhali, 80 mm at Khepupara, 69mm at Bhola, 63mm at Sylhet, the bulletin added.
 
Monwar said after mid-May, mild to moderate heatwave will sweep some regions including Khulna and Rajshahi and "We are expecting Bangladesh will not face deadly heatwave like the month of April."

Mallik suggested avoiding to stay outdoors during the hailstorm as intensity of hailstorms is increasing accompanied with frequent lightning impacted by climate change, which are largely responsible for casualties.

The Met Office recorded 34.6 degrees Celsius on May 6 at Jeshore while the temperature in Dhaka was recorded at 32.6 degrees Celsius during the same day.

Visibly for the first time the meteorologists acknowledged that the climate change phenomenon caused the erratic weather pattern with gradually expanding areas of heatwave, joining the voice with the climate experts and activists.