Portal:Weather

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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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Hurricane Mitch was one of the deadliest and most powerful hurricanes on record in the Atlantic basin, with maximum sustained winds of 180 mph (285 km/h). At the time, Hurricane Mitch was the strongest Atlantic hurricane observed in the month of October, though it has since been surpassed by Hurricane Wilma of the 2005 season. Hurricane Mitch dropped historic amounts of rainfall in Honduras and Nicaragua, with unofficial reports of up to 75 inches (1900 mm). Deaths due to catastrophic flooding made it the second deadliest Atlantic hurricane in history; nearly 11,000 people were killed with over 8,000 left missing by the end of 1998. The flooding caused extreme damage, estimated at over $5 billion (1998 USD, $6.5 billion 2008 USD)...

Recently selected articles: Hurricane Vince, Weather, More...

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This tornado struck the town of Elie, Manitoba on June 22, 2007. It was the first tornado outside the United States to be rated F5 on the Fujita Scale, the most severe level of tornado damage.

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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 26

1972: Subtropical Storm Alpha reached peak intensity east of Savannah, Georgia, where it would make landfall the next day.

May 27

1774: Francis Beaufort, inventor of the Beaufort scale for measuring wind force, was born in Ireland.

May 28

1879: Milutin Milanković, famous for relating the cycle of ice ages to characteristics of Earth's orbit, was born in Erdut, Croatia (then Austria-Hungary).

May 29

1995: A destructive tornado struck western Massachusetts, killing three people in the town of Great Barrington.

May 30

1959: Tropical Storm Arlene made landfall near Lafayette, Louisiana, bringing more than 10 inches (25 cm) of rain to parts of the northern Gulf Coast of the United States.

May 31

1889: The Johnstown Flood, caused by days of heavy rains which led to the failure of the South Fork Dam, killed more than 2,000 people in Johnstown, Pennsylvania.

June 1: Start of the Central Pacific and Atlantic hurricane seasons

1999: American Airlines Flight 1420 overran the runway in a severe thunderstorm, killing 10 passengers and the pilot.

Selected biography

Portrait of C. H. D. Buys Ballot c. 1857

Christophorus Henricus Diedericus Buys Ballot (Dutch pronunciation: [ˈbœys baːˈlɔt]; October 10, 1817 – February 3, 1890) was a Dutch chemist and meteorologist after whom Buys Ballot's law and the Buys Ballot table are named. He was first chairman of the International Meteorological Organization, the organization that would become the World Meteorological Organization. (Full article...)

Previously selected biographies: Sir William Napier Shaw, Johannes Peter Letzmann, 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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