Meteorologists forecast that a weak cold air mass arriving around May 17 will trigger widespread thunderstorms and bring an end to the prolonged hot spell.

Heatwave intensifies across multiple regions

According to the National Center for Hydro-Meteorological Forecasting, the expansion of a western low-pressure zone toward the southeast is continuing to fuel widespread hot weather across many parts of the country, with some areas experiencing severe heat conditions.

On May 15, northern and central Vietnam are expected to reach the peak of the current heatwave.

Temperatures in many areas are forecast to range between 36C and 38C, with some places surpassing 38C, while outdoor surface temperatures may climb above 40C.

Low humidity levels are also making conditions feel increasingly oppressive.

Specifically, northern Vietnam - excluding Dien Bien and Lai Chau provinces - along with areas from Thanh Hoa to Da Nang and eastern localities stretching from Quang Ngai to Dak Lak are expected to experience widespread heat and severe heat, with maximum temperatures commonly reaching 36C-38C and some areas above 38C.

The lowest humidity levels are forecast at around 45-50%.

In southern Vietnam, hot weather is also continuing, with temperatures ranging from 35C to 36C and some areas exceeding 36C.

Humidity levels there are expected to remain around 50-55%.

By May 16, the heatwave in northern Vietnam is forecast to ease slightly but remain widespread, with temperatures generally ranging from 35C to 37C and some locations still above 37C.

Cold air to trigger thunderstorms from May 17

Meteorologists say the widespread heatwave in northern Vietnam could end around May 17 as a weak cold air mass begins affecting the region.

From the night of May 16-17, scattered showers and thunderstorms are forecast across northern Vietnam, with some areas likely to experience heavy to very heavy rainfall.

The storms are expected to bring an end to the prolonged heatwave.

In areas from Thanh Hoa to Da Nang and eastern localities stretching from Quang Ngai to Dak Lak, scattered showers and thunderstorms are expected from the afternoon and evening of May 17, mainly concentrated later in the day.

Other regions may also experience isolated showers and thunderstorms, with some areas seeing scattered evening rainfall.

According to weather experts, the late-season cold air mass is expected to primarily bring thunderstorms to northern Vietnam and mountainous areas from Thanh Hoa to Ha Tinh.

As the cold air collides with hot and humid air near the surface, large temperature differences may create conditions for extreme weather events including tornadoes, lightning, hail and strong winds.

Meteorological authorities also forecast that over the next month, heatwaves are likely to intensify across northern Vietnam, areas from Thanh Hoa to Hue and the south-central coastal region.

The number of hot days in northern and central Vietnam is expected to remain above long-term averages, while southern Vietnam may gradually cool down toward the end of May.

However, scattered nationwide periods of showers and thunderstorms are still likely.

Bao Anh