Arabia Weather - The latest weather data from the Arab Weather Center, in addition to the maps specialized in predicting fog, indicate that the chances of fog formation will continue tonight and until the early morning hours of Tuesday in some areas, as a result of the formation of clouds touching the surface of the Earth, which will reduce the extent of Horizontal visibility, especially above mountain heights.
In light of the expectations of fog forming in some areas of the Kingdom tonight and tomorrow morning, learn about the types of fog and how it forms.
Fog is considered one of the forms of condensation of water vapor present in the air, when the temperature drops to or below the dew point, which is the degree at which water vapor condenses, as it is the process in which water vapor turns from the gaseous state to the liquid state, which appears in the form of droplets of water. .
Fog occurs when the relative humidity rises to above 90% to 100%, with cooling occurring when the air comes into contact with the surface of the earth, in addition to an important factor, which is the presence of condensation nuclei, which are very small objects suspended in the air such as smoke and dust.
There are many types of fog, including the following:
- Radiation fog occurs at the end of the night and the beginning of the day in the early morning hours above the Earth’s surface when the Earth loses its heat due to radiation and cools, thus cooling the air in contact with it. In the event that water vapor is available and the air temperature reaches or below the dew point, provided that the speed The wind is light and not steady, allowing the warmer air to pass over the cold surface and touch it, thus cooling to the dew point.
- Fog Valley , which forms in the valley and can cover a layer 450 meters thick. It occurs in valleys as a result of cold winds descending from the top of the mountains to the valleys because cold air is heavier than warm air, and usually in the low areas of valleys there are bodies of water, which increases the humidity level.
- Transitional fog "Fog Advection" occurs when warm, humid air blows over a cold surface. The temperature of the air in contact with the Earth's surface cools. When it cools and the air temperature reaches the dew point, fog begins to form. Transitional fog can form during the day or night and is common. Occurs in the winter when air masses move to land coming from the seas or oceans.