Weather sign of weather

Clear: it means that there are no clouds or scattered clouds in the sky, but the cloud amount is less than110, which is called clear. Sometimes there are very high and thin clouds in the sky, but they have little effect on sunlight.

Cloudy: it can be cloudy when the amount of low clouds in the sky accounts for 4/ 10 ~ 7/ 10 of the sky area or the amount of high clouds accounts for more than 6/ 10 of the sky area.

Cloudy day: it is called cloudy when the amount of clouds in the middle and low clouds accounts for more than 8/ 10 of the sky area. Cloudy days are dark days, and little or no sunlight can penetrate the clouds.

Fog: refers to a large number of water droplets or ice crystal particles suspended in the air near the ground. When this aggregate reduces the horizontal visual distance below 1000 meters, it is called fog; When the visible distance drops to 1000 ~ 10000 meters, it is called light fog.

Light rain: it is called light rain when the rainfall in 4 hours is less than 10.0mm or 1 hour is less than 2.5 mm. ..

Moderate rain: the rainfall within 24 hours is 1 0.0 ~ 24.9mm or the rainfall within1hour is 2.5 ~ 8.0mm..

Rainstorm: Rainstorm is called when the rainfall in 24 hours is less than 25.0 ~ 49.9mm or 1 hour reaches 8.1~15.9mm..

Rainstorm: Rainstorm is called when the rainfall reaches or exceeds 50.0mm in 24 hours and 1 hour reaches or exceeds16.0mm.. Heavy rain occurs when the rainfall reaches 100.0 ~ 199.9 mm; The rainfall of 200.0 mm is called rainstorm;

Thundershower: refers to sudden rainfall accompanied by thunder and lightning, which is characterized by short rainfall time, sudden start and end, and great changes in precipitation intensity. Intermittent precipitation accompanied by lightning and thunder.

Hail: It is a kind of solid precipitation. Refers to spherical or conical ice cubes with a diameter of 5.0 mm, and it will rain heavily in the clouds. The shape is also irregular. The monomer is called hail block, which consists of transparent and opaque layers. The diameter of large hailstones can reach 19 cm.

Freezing rain: raindrops freeze on the ground below 0℃, also known as rain song (frozen by fog drops, called rime), which often falls off the power lines, freezing the road surface and affecting communication, power supply and traffic.

Sleet: refers to the precipitation phenomenon that raindrops and wet snow fall to the ground at the same time. When it happens, the near-surface temperature is slightly higher than 0℃. When snow falls into this layer of air, part of it melts into water droplets.

Light snow: refers to the snow whose horizontal visibility exceeds 1000m when it snows, or whose snowfall is less than 2.5mm within 24 hours.

Medium snow: refers to the snowfall with horizontal visibility exceeding 500 ~ 1000 meters or snowfall less than 2.5 ~ 5.0 mm within 24 hours. ..

Blizzard: refers to the snowfall with horizontal visibility less than 500 meters or snowfall greater than 5.0 mm within 24 hours.

Frost: In the transitional season of spring and autumn, the temperature is higher than 0℃ during the day and drops below 0℃ for a short time at night. When it appears, the temperature in the louver shall not be lower than 0℃; Frost often appears on the ground or on the surface of objects.

Low-pressure trough and high-pressure ridge: on the fluctuating high-altitude westerly airflow, the trough corresponds to the low-pressure trough, with active warm air in front of the trough, rain and snow weather, controlled cold air behind the trough, and strong wind cooling weather; The peak corresponds to the ridge of high pressure and the sky is clear.

Cold and warm fronts: A cold front is the front of cold air. At the junction of cold air and warm air mass, cold air pushes towards warm air. It is windy and rainy on the cold front, and windy and cool after the front; On the contrary, it is a warm front, the front is rainy, and it turns cloudy and sunny after the front, and the temperature rises.

Strong wind: expressed by wind vector, consisting of wind mast and wind plume. The wind pole refers to the direction of the wind, with eight directions. The wind plume is represented by 3 or 4 short strokes and triangles, perpendicular to the right side of the wind pole end (northern hemisphere).

Six-level wind: refers to the wind with a wind speed of 10.8 ~ 13.8 m/s above the ground.

Level 7 wind: refers to the wind with a wind speed of 13.9 ~ 17. 1 m/s above the ground.

8- 12 wind: the wind speed above the ground10m is17.2-20.7m/s, 20.8-24.4m/s, 24.5-28.4m/s and 28.5-32.6m/s respectively.

Typhoon: refers to a strong warm-hearted cyclone vortex that occurs in the tropical ocean. When the average wind force near the center reaches 12 or above, it is called a typhoon. 1. Time division: The daytime mentioned in the weather forecast refers to 8: 00 to 20: 00 local standard time, in which 17: 00 to 20: 00 is called evening; Call night after 20 o'clock to 8 o'clock the next day.

2. Weather conditions (the division between cloudy and sunny): sunny means that the amount of clouds in the sky is less than 30% (that is, 30%) all day; Cloudy is the sky condition when there are 4-70% medium-low clouds or 6- 10% high clouds in the sky; Partial cloudy is the sky condition when there are 1-3% medium-low clouds or 4-50% high clouds in the sky; A cloudy day is a weather phenomenon in which the sky is dark and the clouds are densely covered, or even if there are gaps in the clouds, the sky still feels dark (accounting for more than 80% of the total amount of clouds), and occasionally weak sunlight can be seen from the gaps in the clouds.

Fog: A visible aggregate of a large number of tiny water droplets (or ice crystals) suspended in the atmosphere near the ground. The only difference between fog and clouds is whether they touch the ground or not. Fog greatly reduces the horizontal visibility of the ground. According to the regulations of the International Meteorological Organization, when the visibility drops below 1 km, it is called fog.

Cloud amount and cloud height: Cloud amount refers to the percentage of clouds covering the sky; Cloud height refers to the vertical distance from the bottom of the cloud to the ground of the station.

3. Temperature: The temperature mentioned in the weather forecast refers to the air temperature measured in the open air without direct sunlight (generally measured by blinds). The highest temperature is the highest temperature in a day, which generally appears at 14- 15, and the lowest temperature generally appears at 5-6 am.

4. Precipitation: Precipitation includes rainfall, snowfall, sleet and hail.

Rainfall: The meteorological department generally refers to the rainfall within 24 hours. Rainfall is generally divided into eight levels: sporadic light rain, light rain, shower, moderate rain, heavy rain, heavy rain, heavy rain, heavy rain, heavy rain and heavy rain. According to the 24-hour precipitation (mm), the rainfall grades are: light rain 0. 1 ~ 9.9, moderate rain 10.0 ~ 24.9, heavy rain 25.0 ~ 49.9 and heavy rain 50.0 ~ 99.9.

Hail: Hard spherical, conical or irregularly shaped solid precipitation.

Snowfall is divided into light snow, medium snow, heavy snow, blizzard and blizzard according to snowfall. Among them, blizzard is the snow with high snowfall intensity (the horizontal visibility distance is less than 500m during snowfall or the snowfall within 24 hours is greater than15 mm); Blizzard, also known as blizzard, is a weather phenomenon that strong winds carry a lot of snow and it is impossible to judge whether there is snowfall at that time, and the horizontal visibility is less than 1km.

5. Wind: Wind refers to the horizontal flow of air. Expressed by wind direction and wind speed: the wind direction is divided into sixteen directions, which refers to the direction in which the wind blows; Wind speed is expressed in wind scale or m/s, and it is divided into average wind speed represented by 2-minute average situation and instantaneous wind speed represented by instantaneous situation.

The strength of the wind is expressed by the wind speed, generally measured by the size of the wind or how many meters per second. There are thirteen grades:

Static wind: that is, level 0 wind.

Breeze: that is, level 4 wind. Wind with a wind speed of 5.5-7.9 m/s

Breeze: that is, level 3 wind.

Strong wind: that is, 8 winds. Wind with an average wind speed of17.2-20.7m/s.

Strong wind: 10 wind.

Storm: 1 1 wind. A wind with a wind speed of 28.5-32.6 m/s.

Hurricane: the wind above 12. Release the national weather forecast for the 20 15 Spring Festival. It is estimated that during the Spring Festival holiday, there will be no large-scale cold wave, low temperature, rain, snow and freezing weather in China, and the meteorological conditions are generally conducive to coal, electricity and oil transportation and holiday travel. Among them, there are two rain and snow weather processes in the northern region, and the temperature is higher than normal1~ 3℃; There are more rainy days in the south, and the temperature is close to normal or slightly higher; There are moderate to severe haze or fog in parts of central and southern North China, Huanghuai and other places.