Due to the influence of a low pressure trough being compressed and gradually moving southward, from the evening and night of April 16 to April 17, the weather in Lao Cai province turned bad.
Many areas have scattered showers and thunderstorms, locally with moderate to heavy rain with common rainfall from 20 - 40mm, with points exceeding 60mm. During thunderstorms, extreme weather phenomena such as tornadoes, lightning, hail and strong gusts are likely to occur.
It is forecasted that this rain will not only occur for a short time but may last for 3-4 consecutive days, interspersed with days of moderate rain, localized heavy rain accompanied by strong thunderstorms. It is noteworthy that the risk of tornadoes, hail and lightning strikes is assessed at a high level in many localities in the province.
According to the National Center for Hydro-Meteorological Forecasting, a cold air mass has formed on mainland China and is moving southward.
Around the night of April 16, this cold air mass will weakly strengthen down to the Northern region, affecting Lao Cai, causing light showers and thunderstorms in some places, and gradually reducing the temperature.
The weather turns mild and cool, high mountainous areas may experience mild cold at night and in the morning, ending the localized hot weather in low-lying areas.
Notably, from the evening and night of April 17, a high-altitude wind convergence zone formed and operated clearly in the Lao Cai area, causing thunderstorms to expand and increase intensity over a wide area.
In the context of the weather maintaining previous hot weather, the sudden phase transition to thunderstorms increases the risk of extreme phenomena arising.
People need to be especially wary of tornadoes and strong gusts of wind that can cause roofs to be blown off and works to be damaged; hail affecting agricultural production; lightning strikes that are dangerous to life.
In mountainous areas, localized heavy rain can cause sudden flash floods on small streams and the risk of landslides on slopes, especially in places with loose geological foundations or in the process of leveling. Meanwhile, low-lying areas need to be wary of localized flooding when heavy rain occurs in a short time.
