Portal:Weather
The weather portal
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...)
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A jet stream is a fast flowing, relatively narrow air current found at the tropopause, the transition between the troposphere (where temperature decreases with height) and the stratosphere (where temperature increases with height). Jet streams are typically located at 10-15 kilometers above the surface of the Earth. They form near boundaries of adjacent air masses with significant differences in temperature, such as the polar region and the warmer air to the south. The path of the jet typically has a meandering shape, and these meanders known as Rossby waves. Rossby waves propagate westward with respect to the flow in which they are embedded, which translates to a slower eastward migration across the globe than smaller scale short wave troughs. The major jet streams are westerly winds (flowing west to east) in the Northern Hemisphere.
During the summer, low-level easterly jets can form in tropical regions. A southerly low level jet in the Great Plains of North America helps fuel overnight thunderstorm activity, normally in the form of mesoscale convective systems. A similar northerly low-level jet can form across Australia, instigated by cut-off lows which develop across southwest portions of the country.
Meteorologists use the location of the jet stream as an aid in weather forecasting. The main commercial use of the jet stream is during airline travel, as flying long distances along the jet stream can cut hours off a long distance trip. One type of clear-air turbulence is found in the jet stream's vicinity, which can be a hazard to aircraft. One future benefit of the jet stream could be to augment power generation within the next 10 to 20 years, if technological hurdles can be overcome.
Recently selected articles: Weather front, Water cycle, More...
Did you know (auto-generated) -
- ... that in the 1980s, "Sherman Bonner, The Human Thermometer" presented the weather on an Arkansas TV station?
- ... that the weather forecast for HD 189733 b is "Westerly winds at 2000 m/s, with molten glass showers"?
- ... that after Irish post office clerk Maureen Flavin Sweeney reported worsening weather conditions, Dwight D. Eisenhower agreed to postpone D-Day by 24 hours?
- ... that weather whiplash is the phenomenon of rapid swings between extremes of weather conditions?
- ... that Eric Berger wrote about weather for the Houston Chronicle even before he became a certified meteorologist?
- ... that an attempted British-Norwegian attack on the German battleship Tirpitz was abandoned after two Chariot manned torpedoes were lost due to bad weather?
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Lightning strikes in the outskirts of Oradea, Romania, during a thunderstorm on August 17, 2005. This storm system went on to cause major flash floods over Southern Romania.
Recently selected pictures: Snow-swept trees, Low pressure
More did you know...
...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?
Recent and ongoing weather
- Wikinews weather portal
- March 26, 2021: Tropical moisture ceases to cause severe floods in South East Australia
- February 19, 2021: Winter storms hammer Texas, fatalities reported
- December 28, 2021: Typhoon Phanfone strikes Philippines
- February 1, 2022: Deadly floods in Brazil after heavy rainfall
- April 15, 2022: South African floods kill at least 300 people
- Weather of 2024
- 2024 Atlantic hurricane season
- 2020–21 North American winter
- 2024 Pacific typhoon season
- Tornadoes of 2024
This week in weather history...
April 21
1965: A devastating tornado outbreak killed 58 people near Chicago.
April 22: Earth Day
2011: A nighttime tornado, caused major damage in parts of St. Louis, Missouri, including Lambert-St. Louis International Airport, but amazingly caused no deaths and few injuries.
April 23
1792: John Thomas Romney Robinson, inventor of the cup-anemometer, was born in Dublin, Ireland.
April 24
1908: One of the deadliest tornadoes in US history killed at least 143 people in Louisiana and Mississippi.
April 25
1994: An F4 tornado killed three people on the first day of a 3-day tornado outbreak.
April 26
1998: Cyclone Alan which had been impacting French Polynesia with several days of strong winds and heavy rain that killed 10 people, dissipated west of Tahiti.
April 27
2011: The deadliest American tornado outbreak in 76 years killed more than 300 people in the Southern United States.
Selected biography
Vilhelm Friman Koren Bjerknes ForMemRS (/ˈbjɜːrknɪs/ BYURK-niss, Norwegian: [ˈbjæ̂rkneːs]; 14 March 1862 – 9 April 1951) was a Norwegian physicist and meteorologist who did much to found the modern practice of weather forecasting. He formulated the primitive equations that are still in use in numerical weather prediction and climate modeling, and he developed the so-called Bergen School of Meteorology, which was successful in advancing weather prediction and meteorology in the early 20th century. (Full article...)
Previously selected biographies: Anders Celsius, Robert FitzRoy, More...
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Other candidates:
- Featured Article Review: 2005 Atlantic hurricane season (Discussion)
- Featured List Removal Candidate: List of storms in the 2005 Atlantic hurricane season (Discussion)
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WikiProjects
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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