The foggy condition led to an average of poor visibility between 300 meters and 500 meters.
By several hours late, the National Center for Hydro-Meteorological Forecasting issued an official information of the phenomenon.
Accordingly, this is the form of the stratospheric fog, formed when weaker cold air mass triggering higher humidity into the mainland.
One more reason was due to an appearance of temperature inversion at an altitude of 500-1500 meters in combination with the calm condition at the surface.
According to Head Office of National Center for Hydro- Meteorological Forecasting Tran Quang Nang, the weather condition is expected to happen between the morning and afternoon until this weekend.
The weather experts said that the foggy condition led to low visibility for drivers on the roads, especially on national highways and in airports.
