Portal:Weather

Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature, precipitation, and other atmospheric conditions, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth.

Weather is driven by air pressure, temperature, and moisture differences between one place and another. These differences can occur due to the Sun's angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations: the Hadley cell, the Ferrel cell, the polar cell, and the jet stream. Weather systems in the middle latitudes, such as extratropical cyclones, are caused by instabilities of the jet streamflow. Because Earth's axis is tilted relative to its orbital plane (called the ecliptic), sunlight is incident at different angles at different times of the year. On Earth's surface, temperatures usually range ±40 °C (−40 °F to 104 °F) annually. Over thousands of years, changes in Earth's orbit can affect the amount and distribution of solar energy received by Earth, thus influencing long-term climate and global climate change.

Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes, as most atmospheric heating is due to contact with the Earth's surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Earth's weather system is a chaotic system; as a result, small changes to one part of the system can grow to have large effects on the system as a whole. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture and industry have modified weather patterns.

Studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiter's Great Red Spot, is an anticyclonic storm known to have existed for at least 300 years. However, the weather is not limited to planetary bodies. A star's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind. (Full article...)

The 2008 Super Tuesday tornado outbreak was a deadly tornado outbreak which affected the Southern United States and the lower Ohio Valley on February 5–6, 2008. In total, 87 tornadoes were confirmed in the outbreak's 15 hour span. Several destructive tornadoes struck heavily populated areas, most notably in the Memphis metropolitan area, in Jackson, Tennessee, and the northeastern end of the Nashville metropolitan area. Fifty-seven people were killed in the outbreak by tornadoes across four states and 18 counties, with hundreds injured and property damage totaling more than $500 million (USD).

The outbreak was the deadliest in the U.S. since the May 31, 1985 outbreak that killed 76 across Ohio and Pennsylvania (and also killed 12 in Ontario, Canada). It also was the deadliest tornado outbreak in both Tennessee and Kentucky since the 1974 Super Outbreak. In addition to the tornadoes, the same system produced significant straight-line wind damage, hail as large as softballs, or 4.50 inches (11 cm) in diameter, major flooding, significant freezing rain, and heavy snow across many areas of eastern North America.

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Mammatus (also known as mamma or mammatocumulus, meaning "breast-cloud") is a meteorological term applied to a cellular pattern of pouches hanging underneath the base of a cloud. The name "mammatus" is derived from the Latin mamma (breast), due to the resemblance between the shape of these clouds and human female breasts. Mammatus are most often found on the anvil cloud that extends from a cumulonimbus, and therefore are commonly associated with severe weather.

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...that the Flying river is the name given to the transport of water vapor from the Amazon rainforest to southern Brazil?

...that hurricane shutters are required for all homes in Florida unless impact-resistant glass is used?

...that the Joint Institute for Marine and Atmospheric Research is a combined weather and ocean research institute with the cooperation of the Office of Oceanic and Atmospheric Research and the University of Hawaiʻi?

...that the SS Central America was sunk by a hurricane while carrying more than 30,000 pounds (13,600 kg) of gold, contributing to the Panic of 1857?

...that a hurricane force wind warning is issued by the United States National Weather Service for storms that are not tropical cyclones but are expected to produce hurricane-force winds (65 knots (75 mph; 120 km/h) or higher)?

...that the Automated Tropical Cyclone Forecasting System is a software package for tropical cyclone forecasting developed in 1988 that is still used today by meteorologists in various branches of the US Government?


Sir William Napier Shaw FRS (4 March 1854 – 23 March 1945) was a British meteorologist. He introduced the tephigram, a diagram for evaluating convective instability in the atmosphere. He also served as president of the International Meteorological Committee and Royal Meteorological Society. (Full article...)

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The scope of WikiProject Weather is to have a single location for all weather-related articles on Wikipedia.

WikiProject Meteorology is a collaborative effort by dozens of Wikipedians to improve the quality of meteorology- and weather-related articles. If you would like to help, visit the project talk page, and see what needs doing.

WikiProject Severe weather is a similar project specific to articles about severe weather. Their talk page is located here.

WikiProject Tropical cyclones is a daughter project of WikiProject meteorology. The dozens of semi-active members and several full-time members focus on improving Wikipedia's coverage of tropical cyclones.

WikiProject Non-tropical storms is a collaborative project to improve articles related to winter storms, wind storms, and extratropical cyclones.

Wikipedia is a fully collaborative effort by volunteers. So if you see something you think you can improve, be bold and get to editing! We appreciate any help you can provide!

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