How to judge the weather, high school physics, to tell the truth: early view of the southeast, late view of the northwest. What does this mean?

This does not mean looking at the direction, but judging by the clouds above that direction.

The generation and dissipation of clouds and the evolution and transformation among various clouds are all carried out under certain water vapor conditions and atmospheric movement conditions.

Cirrus clouds often have fronts (especially warm fronts), low pressure or low pressure troughs, which indicates that rain is coming.

Battery clouds usually have a thunderstorm every 8- 10 hour.

Cloud-to-cloud means that the upper and lower clouds move in different directions, which often occurs near the front or low pressure, so it indicates rain, and sometimes the wind direction of the clouds is opposite to the ground, so there is a saying that "it will change against the wind."

When the pig crossed the river, it rained cats and dogs: the pig refers to the broken rain clouds in nimbostratus. The appearance of this cloud indicates that there is a lot of water vapor in nimbostratus, and a rainstorm is coming. Sometimes broken rain clouds are blown to cloudless places by strong winds, and it is also a precursor to rain to see clouds like river pigs floating across the "Milky Way" at night.

Cotton cloud, rain is coming: cotton cloud refers to flocculent cumulus clouds, indicating that the middle atmosphere is very unstable. If there is enough water vapor in the air and there is upward movement, cumulonimbus clouds will form and thunderstorms will come.

Gray cloth hangs over the sky, and it rains continuously: Gray cloth cloud refers to nimbostratus, which is mostly formed by thickening and metamorphosing of high-level clouds, with a large and thick range, and sufficient water vapor in the clouds, which often produces continuous precipitation.

Clouds in the east, chariots and horses; The clouds go south and the water rises; Clouds to the west, covered with hemp fiber; Clouds moving north are beneficial to drying wheat: according to the moving direction of clouds, it is predicted that the weather will be fine, and clouds moving east and north indicate that the weather will be fine; The clouds move west and south, which indicates that it will rain. The moving direction of a cloud usually indicates the wind direction at its height. This proverb explains the distribution of clouds in different parts of low pressure. Suitable for low-altitude fast-moving clouds that are densely covered all day.

Fish Scale Day means cirrocumulus. The appearance of such clouds indicates that the upper atmosphere is unstable. If the clouds continue to decrease and thicken, it means that it is going to rain or wind in front of the trough with low pressure in this area.

Carp spots in the sky don't need to be turned over in the sun: Carp spots refer to translucent cumulus clouds, which are often controlled by denatured high-pressure air masses that change from cold to warm. If the clouds don't continue to thicken, it will be sunny in the short term.

Dark clouds drive the sunset, but it doesn't fall today or tomorrow: when the sun sets, a wall-like dark cloud rises under the western horizon to drive the sun, indicating that the dark clouds are moving eastward, and the rainy weather system in the west is moving and it is going to rain. Generally speaking, if there are clouds, it will rain that night; If you catch the high clouds, it will rain the next day. However, if the dark clouds in the west are lumpy or discontinuous, or some areas are cloudy, it is not a sign of rain in the future.

When the northwest opens, bright sunshine refers to rainy days. At this time, the clouds in the northwest crack and reveal a blue sky, which is called "opening the sky". This shows that the local area is already at the back of the rainy weather system. As the rainfall system moves eastward, the local rainfall will stop and the weather will improve.

Now the sun appears, but it hasn't been seen for three days: in spring and summer, at noon on rainy days, the clouds split and the sun appeared, but the clouds quickly gathered and became thicker, which shows that the local area was affected by the quasi-static front, and the airflow near the quasi-static front was strong and changeable. When the updraft is strengthened, the clouds become thicker and the rainfall increases; When the updraft weakens, the clouds become thinner and the rainfall decreases or stops; Around noon, the sun shines strongly, the upper part of the cloud is heated and evaporated, or the updraft below the cloud weakens, and the zenith cloud will split. As the solar radiation weakens or the updraft under the cloud strengthens, the split clouds gather again and become thicker. So "sunny now" often indicates that it will continue to rain. This proverb is similar to such proverbs as "when the sun smiles, the temples are soaked" and "when the sun shines, the next foot falls down".

Sunset shoots at the foot, and the rain falls within three days: it refers to the sun shining through the gap in the clouds, which is called "shooting at the foot". The shooting at the foot appears in the evening, indicating strong convection and indicating rain.

Don't go out in the morning, and go to Wan Li Road at night: there are no clouds in the east and clouds in the west in the morning. The sun shines on the clouds and scatters rosy clouds, indicating that there is a lot of water vapor in the air or a rainfall system moves in. During the day, the air is generally unstable and the weather will turn rainy. If there is a sunset glow in the evening, it means that the sky in the west has cleared up, and the general convection is weakened at night. The clouds in the east that form the rosy clouds will move eastward or tend to dissipate, indicating that the sky is clear.

Long sunny, foggy, cloudy, long cloudy, foggy and sunny: it means that there is fog after a long sunny day, indicating that the warm and humid airflow moves and the air is humid, which is a sign of rainy days; Fog appears after a long period of cloudy days, indicating that the clouds in the sky become thinner, split and dissipate, and the ground temperature drops, so that water vapor condenses into radiation fog. After sunrise, the fog will disappear and sunny days will appear.

In the morning of warm season, if castle clouds appear on the horizon, it means that the wet air layer at this height is already very unstable. At noon, once the low-level convection develops, the upper and lower unstable layers will merge, resulting in strong convective movement, cumulonimbus clouds and thunderstorms. So there is a proverb "pagoda clouds in the morning, and it rains cats and dogs in the afternoon".

In addition, clouds with weather omen often have certain continuity, seasonality and locality in the evolution process. Clouds in the sky move from a distance in the order of cirrus, cirrostratus high-level clouds and nimbostratus, and gradually change from less to more, from high to low, from thin to thick, indicating that rainy weather is coming; On the contrary, if the clouds change from low to high, from thick to thin, and from layered clouds to scattered clouds, there will be no rainy weather. In the warm season morning, if there are isolated clouds (light cumulus clouds) with flat bottom and convex top in the sky, or white broken clouds (broken cumulus clouds) that move quickly, it indicates that the air in the middle and lower layers is relatively stable and the weather is fine.

In addition, the color of clouds can also indicate some kind of weather. For example, the color of hail cloud is first white and then black, and then red appears in the cloud, forming a white, black and red distorted cloud with khaki edges. Black is caused by the sun's inability to penetrate clouds; White is the result of non-selective scattering or reflection of sunlight by clouds; Red and yellow are the phenomena that some cloud droplets (ranging from one thousandth to one hundredth of a millimeter in diameter) in the cloud selectively scatter sunlight. Sometimes rain clouds are pale yellow, but the color of the clouds is uniform and will not stir. There are also many proverbs that predict hail from the color and shape of clouds. For example, there is a proverb in Inner Mongolia, such as "I am not afraid of the darkness in the clouds, but I am afraid of the red darkness in the clouds, and I am most afraid of the white worms under Huang Yun". In Shaanxi, there is "Huang Yun turned over and hail; Stir clouds and hail in groups; There are proverbs such as "When clouds fight, it will hail" and "When the dark clouds in Huang Yun are red, they will be stirred repeatedly, and many hail disasters are serious". There are also some sayings, such as "the dark clouds roll into a ball in the afternoon, and the wind, rain and hail come together", "The sky is yellow and sultry, and the Tianhe water growls to prevent ice eggs", all of which indicate that when the air convection is strong, the clouds develop rapidly, like smoke rushing up, and the clouds roll up and down, which is easy to hail.