A mild heatwave swept over 10 districts yesterday, and the country may experience a severe one this month, according to the Bangladesh Meteorological Department.

The highest temperature in the country was recorded in Rajshahi at 38 degrees Celsius, the level of a moderate heatwave.

The other districts experiencing the heatwave were Pabna, Sirajganj, Naogaon, Dinajpur, Nilphamari, Moulvibazar, Rangamati, Jashore, and Chuadanga.

According to BMD, a mild heat wave is considered when maximum temperature stays between 36 and 37.9 degrees Celsius, moderate between 38 and 39.9 degrees Celsius, severe between 40 and 41.9 degrees Celsius, and very severe 42 degrees Celsius or above.

According to BMD data, the country's normal maximum temperature in April is 33.2 degrees Celsius, the highest among all months.

The present weather conditions with soaring temperatures could continue for two to three days, BMD Meteorologist Hafizur Rahman told The Daily Star. The mercury may start to fall afterwards.

Some areas may experience rainfall in the next few days, he said, adding that there was a noticeable amount of rainfall in the Sylhet district over the past few days.

In its weather bulletin, BMD also said Sylhet was the only district to see rainfall with 5mm of rain in the 24 hours till 6:00am yesterday.

It said rain with lightning flashes and temporary gusty winds were likely to occur at one or two places over Mymensingh, Dhaka, Chattogram and Sylhet divisions during a 24-hour period from this morning.

During the period, weather may remain mainly dry with temporary partly cloudy sky elsewhere over the country.

BMD also forecast rainfall in different areas of the country for the next three days.

HEATWAVES, CYCLONE LIKELY

In its monthly weather outlook for April, BMD said two to four mild to moderate heatwaves and one to two severe ones are likely to occur over the country this month.

Besides, one to two low pressure systems are likely to form over the Bay of Bengal and one of them may intensify into a depression or cyclone, according to the outlook released last week.

On the other hand, there are possibilities of light to moderate thunderstorms with hail over a 5- to 7-day period, and severe thunderstorms with hail at places over the country over a 1- to 3-day period.

Rainfall during the month is likely to be below normal over the country, while day and night temperatures are likely to be above normal.

The water flow of the main rivers may be normal this month.

However, the water levels of the rivers in the northeast may increase rapidly due to moderate to heavy rainfall in the region and adjacent catchment areas in the second half of this month.

Besides, the average daily evaporation may be 3.5-5.5mm, and the average daily sunshine may be between 6.5 and 8.5 hours this month.