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Portal:Weather

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Weather refers to the state of the Earth's atmosphere at a specific place and time, typically described in terms of temperature, humidity, cloud cover, and stability. 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 Tip at its peak intensity
Satellite image of Tip at its peak intensity

Typhoon Tip was the largest and most intense tropical cyclone on record. The nineteenth tropical storm and twelfth typhoon of the 1979 Pacific typhoon season, Tip developed out of a disturbance in the monsoon trough on October 4 near Pohnpei. Initially, a tropical storm to its northwest hindered the development and motion of Tip, though after it tracked further north Tip was able to intensify. After passing Guam, it rapidly intensified and reached peak winds of 305 km/h (190 mph) and a worldwide record low sea-level pressure of 870 mbar (hPa, 25.69 inHg) on October 12. At its peak strength, it was also the largest tropical cyclone on record with a diameter of 2,220 km (1,380 mi). It slowly weakened as it continued west-northwestward, and later turned to the northeast under the influence of an approaching trough. Tip made landfall on southern Japan on October 19, and became an extratropical cyclone shortly thereafter.

U.S. Air Force Reconnaissance flew into the typhoon for 60 missions, making Tip one of the most closely observed tropical cyclones. Rainfall from the typhoon breached a flood-retaining wall at a United States Marine Corps training camp in the Kanagawa Prefecture of Japan, leading to a fire which injured 68 and killed 13 Marines. Elsewhere in the country, the typhoon led to widespread flooding and 42 deaths, and offshore shipwrecks left 44 killed or missing.

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The May 22-23, 1981 Tornado Outbreak was a series of destructive tornadoes which injured 12 people and caused $32.8 million (1981 USD) in damage. However, the outbreak is most notable for the spectacularly photogenic Cordell, Oklahoma tornado seen above, which has appeared in many tornado videos and documentaries. Tornadoes are normally oriented vertically, however this tornado was impacted by a gust front from its parent thunderstorm, which stretched it in a horizontal direction. The tornado produced F2 damage, and dissipated shortly after this photo was taken.

Recently selected pictures: Mammatus clouds, Von Kármán vortex street, Crepuscular rays, More...

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...

October 10

1989: Typhoon Dan struck the Philippines and passed over Manila, leaving hundreds of thousands homeless and killing 58 people.

October 11

2005: Hurricane Vince made landfall on the Iberian Peninsula as a tropical depression, the only tropical cyclone since the 1800s to do so.

October 12

1981: Hurricane Norma made landfall near Mazatlán, Mexico, killing one person and causing severe crop damage. Its remnants would later cause severe flooding in Texas and Oklahoma, killing five more people.

October 13

1998: Typhoon Zeb reached peak intensity east of the Philippines, with maximum sustained winds of 180 miles per hour (290 km/h). The storm would make landfall near Ilagan the next day, killing more than 100 people.

October 14

2014: A major snowstorm and series of avalanches, due in part to the remnants of Cyclone Hudhud, killed 43 people in central Nepal.

October 15

1987: The Great Storm of 1987 hit France and England.

October 16

1975: GOES-1, the first Geostationary Operational Environmental Satellite was launched to observe cloud patterns, surface temperatures, and other atmospheric trends best viewed from space.

Selected biography

Wladimir Peter Köppen

Wladimir Petrovich Köppen (/ˈkɜːpən/ KUR-pən; German: [ˈkœpn̩]; Russian: Влади́мир Петро́вич Кёппен, romanizedVladímir Petróvich Kyoppen, IPA: [vlɐˈdʲimʲɪr pʲɪˈtrovʲɪtɕ ˈkʲɵp(ː)ʲɪn]; 25 September 1846 – 22 June 1940) was a Russian–German geographer, meteorologist, climatologist and botanist. After studies in St. Petersburg, he spent the bulk of his life and professional career in Germany and Austria. The Köppen climate classification system, named after a proposal he first made in 1884, with some modifications, is still widely used. Köppen made significant contributions to several branches of science, and coined the name aerology for the science of the upper atmosphere. (Full article...)

Previously selected biographies: John Park Finley, Edward Norton Lorenz, 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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