How to judge the weather?

Long-term observation and practice show that the generation and dissipation of clouds and the evolution and transformation between various clouds are all carried out under certain water vapor conditions and atmospheric movements. People can't see water vapor or atmospheric movement, but we can see every move of water vapor and atmospheric movement from the evolution of clouds, and water vapor and atmospheric movement play an extremely important role in weather phenomena such as rain, snow, ice and hail. For thousands of years, working people in our country have summed up rich experiences of "knowing the weather by looking at clouds" according to the changes of cloud shape, direction, moving speed, thickness and color in production practice, and compiled these experiences into proverbs.

"The sky is hooked with a hook cloud, and the ground is dripping with rain": Hook cloud refers to a cirrus cloud. Behind this cloud, there are often fronts (especially warm fronts), low pressure or low pressure troughs moving, which indicates that rain is coming.

"battery cloud, raining": battery cloud refers to fort-shaped altocumulus or fort-shaped stratocumulus, which mostly appears in front of the trough of low pressure, indicating that the air is unstable, and thunderstorms usually come every 8-1 hours.

"Clouds cross clouds, and it's raining": Clouds cross clouds means that the moving directions of the upper and lower clouds are inconsistent, that is to say, the wind direction of the height of the clouds is inconsistent, which often occurs near the front or low pressure, so it indicates rain, and sometimes the wind direction of the clouds is opposite to that of the ground, so there is a saying that "the sky will change if the clouds go against the wind".

"River pigs cross the river, and it rains cats and dogs": River pigs refer to the broken rain clouds under nimbostratus. The appearance of such clouds indicates that there is plenty of water vapor in nimbostratus and heavy rain is coming. Sometimes broken rain clouds are blown by strong winds to cloudless places, and it is also a harbinger of rain to see a cloud like a river pig floating across the "Milky Way" at night.

"Cotton cloud, rain is coming": Cotton cloud refers to flocculent high cumulus cloud. The appearance of this cloud indicates that the middle atmosphere is very unstable. If there is enough water vapor in the air and there is upward movement, it will form cumulonimbus clouds and there will be thunderstorms.

"Gray cloth hangs in the sky, and the rain will be continuous": The gray cloth cloud refers to nimbostratus, which is mostly formed by the thickening and metamorphosis of high-level clouds. The range is very large and thick, and the water vapor in the clouds is sufficient, which often produces continuous precipitation.

"Clouds go east, and cars and horses pass through; The clouds go south, and the water rises; Clouds to the west, covered with hemp fiber; Clouds go north, which is good for drying wheat ":according to the moving direction of clouds, it is predicted that it will be sunny, and the clouds move east and north, which indicates that the weather will be fine;" The clouds move west and south, which indicates that rain will come. The moving direction of a cloud generally indicates the wind direction at its height. This proverb shows the distribution of clouds in different parts of low pressure. It is suitable for low and fast moving clouds that are densely covered all day.

"Fish-scale sky, even if it doesn't rain, it's windy": Fish-scale sky refers to cirrocumulus. The appearance of such clouds indicates that the upper atmosphere is unstable. If the clouds continue to decrease and thicken, it means that this area is already in front of a trough of low pressure, and it will rain or wind soon.

"Carp spots in the sky need not be turned over when the sun shines": Carp spots refer to altocumulus translucidus, which is often under the control of denatured high-pressure air mass from cold to warm. If the clouds do not continue to thicken, it will still be sunny in the short term.

"Dark clouds catch the setting sun, but not today, but tomorrow": It means that when the sun goes down, a wall-like dark cloud rises below the western horizon to catch the sun, indicating that the dark clouds are moving eastward, and the rainy weather system in the west is moving and it will rain. Generally speaking, if there is a cloud, it will rain that night; If you catch high clouds, it will rain the next day. But if the dark clouds in the west are blocky or disconnected, or the local area is cloudy, it is not a sign of rain in the future.

"The sky is unlocked in the northwest, and the sun is bright in the Ming Dynasty": it means that on rainy days, the clouds in the northwest split, exposing a blue sky, which is called "the sky is unlocked". This shows that the local area is already at the back of the rainy weather system. As the rainy system moves eastward, the local area will stop the rain and the weather will improve.

"The sun appears now and we don't see each other for three days": it means that 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 indicates that the local area is under the influence of the quasi-static front, and the airflow near the quasi-static front is 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 is weakened, and the cloud at the zenith will crack. As the sun's radiation weakens, or the updraft under the clouds strengthens, the split clouds gather again and become thicker. Therefore, "the sun appears now" often indicates that it will continue to rain. " This proverb is similar to such proverbs as "the sun laughs, and the rain breaks the temple" and "the light shines, and the next ten feet".

"Sunset shoots at the foot, and the rain falls within three days": it means that the sun shines down from the gap in the clouds, which is called "the sun shoots at the foot", and it appears in the evening, which indicates that the convection is strong and indicates rain.

"Don't go out in the morning and travel thousands of miles in the evening": there are no clouds in the east and clouds in the west in the morning. Sunlight shines on the clouds and scatters rosy clouds, indicating that there is plenty of water vapor in the air or a rainy system moves in, and the air is generally unstable during the day, so the weather will turn rainy; If there is a sunset glow in the evening, it shows that the sky in the west has cleared up, and the general convection is weakened at night, and the clouds in the east that form the rosy clouds will move more eastward or tend to dissipate, indicating the sky is clear.

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

In the morning of warm season, if a fort cloud appears on the horizon, it indicates that the moist atmosphere at this height is already very unstable. At noon, once the low-level convection develops, the upper and lower unstable levels will combine, which will produce strong convection movement, form cumulonimbus clouds and cause thunderstorms. Therefore, there is a proverb "pagoda clouds in the morning and rain 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 continuously from a distance in the order of cirrus, cirrostratus's high-level clouds and nimbostratus, and gradually change from less to more, from high to low, and from thin to thick, which indicates that rainy weather will come soon; On the contrary, if the clouds change from low to high, from thick to thin, and from layered 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) with fast movement, it indicates that the middle and low air layers are relatively stable and the weather is fine.

In addition, the color of the cloud can also indicate certain weather. For example, the color of the hail cloud is first white with a black background, and then red appears in the cloud, forming white, black and red tangled clouds, and the edge of the cloud is khaki. Black is caused by the sun's inability to penetrate the clouds; White is the result of cloud body's non-selective scattering or reflection of sunlight; Red and yellow is the phenomenon that some cloud droplets (with a diameter of between one thousandth and one hundredth of a millimeter) in the cloud selectively scatter sunlight. Sometimes rain clouds are pale yellow, but the clouds are even in color and do not churn. There are also many proverbs that predict hail from the color and shape of clouds. For example, there are proverbs in Inner Mongolia, such as "If you are not afraid of the dark in the clouds, you are afraid of the dark with red in the clouds, and you are most afraid of the white worms below Huang Yun". In Shanxi, there are "Huang Yun turns over and hails; Stir the clouds and hail in groups; There are proverbs such as "When clouds fight, it will hail" and "When the dark clouds are red and red in Huang Yun, they will stir the clouds repeatedly, and many hail disasters are serious". There are also sayings such as "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 clouds turn over, and the Tianhe water roar to prevent ice eggs", which all indicate that when the air convection is strong, the clouds develop rapidly, like thick smoke rushing straight up, and the clouds roll up and down, it is easy to hail.