Shawdesh Desk:

The first month of the three-month-long pre-monsoon season – March – is forecast to be drier and hotter.

In its monthly weather outlook released on Sunday, the Bangladesh Meteorological Department predicted one or two mild to moderate heatwaves to sweep the country.

A mild heatwave occurs when the maximum temperature reaches 36C or crosses it.

A moderate heat wave refers to a maximum temperature range between 38C and 40C.

On Sunday, Bangladesh’s highest maximum temperature of 33.5C was recorded in Rangamati. Dhaka saw its temperature rose by about 1C to 31.4C on Sunday compared with the day before.

The BMD also predicted less than normal rainfall in March indicating drier conditions to prevail in the month.

The BMD revealed in its latest report titled ‘Changing Climate of Bangladesh’ that the maximum temperature in pre-monsoon months rose between 1980 and 2020.

The report showed that parts of northern, south-western and south-eastern regions are especially prone to warmer days in the pre-monsoon season ending in May.

But significant rise in maximum temperature was recorded in south-western and south-eastern regions in the pre-monsoon season between 1980 and 2020, according to the report.

The minimum temperature, on the other hand, in the per-monsoon season over the studied period rose significantly in parts of central and northern Bangladesh, the report said.

The report said that Dhaka division’s minimum temperature rose by 0.4C in the pre-monsoon season while the maximum temperature rose by 0.1C.

In the pre-monsoon season, Rangpur, Sylhet, Chattogram and Khulna divisions recorded a similar rise in minimum temperature as Dhaka.

The highest rise in maximum temperature of 0.5C in the pre-monsoon season was recorded in Sylhet, followed by a 0.3C rise in Chattogram and a 0.2C rise in Barishal and Khulna, the report said.

The report showed that the pre-monsoon season grew rather drier with less rain over 1980 and 2020 with a decrease of 2.7 days in the number of rainy days every decade.

Parts of the northern region in Rangpur saw a significant drop in rainfall frequency while parts of south-western, central and south-eastern regions saw a significant fall in mean daily precipitation in the pre-monsoon season over 1980-2020.

The BMD research also showed that heatwave days start rather late in March, from the third or last week of the month, particularly after 1997.

Earlier, heat wave days began from the second or third week of March.

‘In the pre-monsoon season, the number of heatwave days increased significantly at many stations near the coast,’ said a line of the report.

The India Meteorological Department in its long-range weather outlook predicted March to be hotter than normal all over the country except for isolated places, including some places in north-east India upstream of Bangladesh.

Both the maximum and minimum temperatures in March are predicted to be above normal.

The IMD also predicted above-normal rainfall in the month in most parts of the country.

The BMD said that February was rather dry with 36 per cent less rainfall than normal despite three spells of rain in the month.

The average minimum temperature in February was 0.2C above normal while the maximum temperature was 0.8C above normal, according to the BMD.

The average temperature in February was 0.5C hotter than normal, the BMD said.

January was also drier than normal with 15.8 per cent less rainfall. The maximum temperature in January was 2C higher than the average normal.

The BMD prediction has no warning about a cyclone forming in March.