Portal:Weather

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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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Satellite image of the storm
Satellite image of the storm

The Christmas 1994 nor'easter was an intense cyclone along the East Coast of the United States and Atlantic Canada. It developed from an area of low pressure in the southeast Gulf of Mexico near the Florida Keys, and moved across the state of Florida. As it entered the warm waters of the Gulf Stream in the Atlantic Ocean, it began to rapidly intensify, exhibiting traits of a tropical system, including the formation of an eye. It attained a pressure of 970 millibars on December 23 and 24, and after moving northward, it came ashore near New York City on Christmas Eve. Due to the uncertain nature of the storm, the National Hurricane Center (NHC) did not classify it as a tropical cyclone.

Heavy rain from the developing storm contributed to significant flooding in South Carolina. Much of the rest of the East Coast was affected by high winds, coastal flooding, and beach erosion. New York State and New England bore the brunt of the storm; damage was extensive on Long Island, and in Connecticut, 130,000 households lost electric power during the storm. Widespread damage and power outages also occurred throughout Rhode Island and Massachusetts, where the storm generated 30-foot (9.1 m) waves along the coast. Due to the warm weather pattern that contributed to the storm's development, precipitation was limited to rain. Two people were killed, and damage amounted to at least $21 million dollars.

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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

This week in weather history...

May 6

1975: An F4 tornado struck Omaha, Nebraska, causing more than $1 billion (1975 USD) in damage.

May 7

1840: The Great Natchez Tornado struck Natchez, Mississippi, killing at least 317 people.

May 8

1995: More than 20 inches (510 mm) of rain in just 12 hours caused major flooding in southern Louisiana, causing more than $1 billion in damage.

May 9

2007: Subtropical Storm Andrea formed off the coast of Florida, causing high winds which contributed to major brush fires.

May 10

1996: The film Twister was released.

May 11

1953: An F5 tornado destroyed areas of downtown Waco, Texas, killing 114 people.

May 12

1948: A Douglas DC-4 crashed while flying into a thunderstorm near Libenge, Congo, killing 31 of the 32 aboard.

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Portrait of John Dalton FRS

John Dalton FRS (/ˈdɔːltən/; 5 or 6 September 1766 – 27 July 1844) was an English chemist, physicist and meteorologist. He introduced the atomic theory into chemistry. He also researched colour blindness; as a result, the umbrella term for red-green congenital colour blindness disorders is Daltonism in several languages. (Full article...)

Previously selected biographies: Sir George Stokes, Clement Lindley Wragge, More...

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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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