What weather does the three horizontal lines represent?

In the weather forecast, the three wavy lines icon represents dense fog.

Fog is a natural phenomenon that is more common in autumn and winter. The principle of fog formation is to condense water vapor in the air into fine water droplets suspended in the air, reducing the horizontal visibility on the ground. To form fog, cooling, humidification, and increasing the content of water vapor are required.

There are many types of fog, such as radiation fog, advection fog, etc. The straight line is generally because there is an obvious front (the confrontation between the cold and warm peaks is obvious), while the curve is because the confrontation between the cold and warm peaks is not obvious.

Extended information:

1. When a meteorological observer observes a certain weather phenomenon, he should record the corresponding symbol in the "Weather Phenomenon" column of the observation book on that day, except for a few phenomenon, and its start and end times should be recorded at the same time. Based on these symbols, combined with the intensity, coexistence and certain characteristics of weather phenomena, a set of symbols that can be filled in on weather maps is called map-filling symbols.

2. Weather symbols are a set of images representing weather phenomena developed to facilitate the public’s understanding and recognition, and are used for television or other public media dissemination.