Rain on December 9 and 10, 2023. December 11, 2023, no fog. On December 12, 2023, the morning was slightly cold. The fog appeared around the BaanPoomPiang Mae Rim Chiang Mai.
It rains on 9-10 December 2023. Today is December 11, 2023. I expected it to be foggy in the morning. But it didn't happen. Maybe because the weather is not as cold as expected. However, today, December 12, 2023, the morning air will cool down a bit. The moisture from the rain persisted, causing the fog to spread around BaanPoomPiang Mae Rim Chiang Mai.
How does fog form?
The principle behind the formation of fog is that, when the air is calm with no strong winds, moisture above the ground or water surface evaporates and turns into water vapor. If the water vapor rises and encounters colder temperatures, it condenses into small droplets floating above the ground or water surface. We know this phenomenon as fog. However, if the water vapor rises to higher altitudes and encounters cold temperatures, condensing into small water droplets, we refer to it as clouds.
If there is a significant amount of tiny dust particles either above the ground or in the sky, it allows small water droplets to adhere well to these dust particles. This causes the formation of thicker groups of fog or clouds, making it more noticeable for observation.
If explained clearly, sunlight shines onto the ground and water surfaces during the daytime, causing them to absorb and retain heat until nighttime when there is no sunlight. As the air above the ground and water starts to cool, the temperature of the air above the ground and water becomes cooler than the temperature of the ground and water.
This temperature difference requires an adjustment to equalize temperatures.
The ground and water must release heat into the upper atmosphere. However, when moisture or humidity is present in the soil particles, the temperature adjustment involves releasing moisture or humidity from the soil particles. The same applies to water surfaces.
During winter, from early evening until midnight, the air above the ground may not be cool enough to cause the condensed water vapor to form tiny water droplets. However, as the air above the ground begins to cool significantly, it allows the condensed water vapor to turn into small water droplets, leading to the formation of fog in the morning.
The rain that fell on December 9-10, 66, likely led to the formation of fog in the early morning of December 11, 66, if the morning air was cold. However, there was no fog on the morning of December 11, 66, probably because the air was not cold enough. The water evaporated into vapor from the rain that fell two days earlier, did not condense, and turned into small water droplets.
With fog in the BaanPoomPiang Mae Rim area, we can predict that the rain on December 9-10, 2023, likely contributed to the formation of fog. If the morning of December 11, 2023, was cool but not cold enough, the moisture evaporating as vapor from the rain that fell two days ago might not have condensed densely into small water droplets, which are what we call fog.
On the other hand, in the morning of December 12, 2023, the colder weather caused the water vapor in the air and the moisture from the ground (part of which might be residual from the rain and has not fully evaporated) to condense densely into small water droplets, floating above the ground. As a result, some scattered fog formed above the ground in the vicinity of the BaanPoomPiang Mae Rim. The fog might have been even thicker if, in the days preceding the rain, there was no rain to wash away dust particles above the ground in this area.
