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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 winter service vehicle (WSV), or snow removal vehicle, is used to clear thoroughfares of ice and snow. Winter service vehicles are usually based on dump truck chassis, with adaptations allowing them to carry specially designed snow removal equipment. Many authorities also use smaller vehicles on sidewalks, footpaths, and cycleways. Road maintenance agencies and contractors in temperate or polar areas often own several winter service vehicles, using them to keep the roads clear of snow and ice and safe for driving during winter. Airports use winter service vehicles to keep both aircraft surfaces, and runways and taxiways free of snow and ice, which, besides endangering aircraft takeoff and landing, can interfere with the aerodynamics of the craft.

The earliest winter service vehicles were snow rollers, designed to maintain a smooth, even road surface for sleds, although horse-drawn snowploughs and gritting vehicles are recorded in use as early as 1862. The increase in motor car traffic and aviation in the early 20th century led to the development and popularisation of large motorised winter service vehicles.

A winter service vehicle clearing roads near Toronto, Ontario, Canada.
A winter service vehicle clearing roads near Toronto, Ontario, Canada.

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

  • ... that in the 1980s, "Sherman Bonner, The Human Thermometer" presented the weather on an Arkansas TV station?
  • ... that Come In was recorded on a hands-free microphone attached to a pair of headphones?
  • ... that Richard Davis made the earliest known continuous land-based weather recordings in New Zealand?
  • ... that Japanese actor Kouhei Higuchi prepared for his role on the television drama adaptation of My Personal Weatherman by learning from a weather forecaster?
  • ... that a Michigan TV station rescued and restored a weather ball that had been sitting for years in a scrapyard?
  • ... that after Irish post office clerk Maureen Flavin Sweeney reported worsening weather conditions, Dwight D. Eisenhower agreed to postpone D-Day by 24 hours?

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A bolt of lightning struck just behind this hill, near Swifts Creek, Victoria, Australia. Lightning kills more people than any other thunderstorm phenomenon (including tornadoes), and strikes approximately 100 times per second across the world.

Recently selected pictures: Moore, Oklahoma tornado damage, Spearman, Texas dust storm, Cordell, Oklahoma tornado, 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...

2008: The Super Tuesday tornado outbreak, the deadliest outbreak in the United States in over 20 years, produced 87 tornadoes which killed 57 people.

February 6

1978: The Blizzard of '78, the worst storm in the area since 1888 and the second large blizzard in as many weeks to hit the eastern United States, began dropping more than 40 inches (100 cm) of snow on parts of the Northeastern United States.

February 7

2009: Record high temperatures and strong, erratic winds contributed to the deadliest wildfires in Australia's history. 3,500 buildings were destroyed, and 173 people were killed.

February 8

2013: A severe nor'easter began affecting the northeastern United States, bringing blizzard conditions and record snowfall to parts of New England.

February 9

1870: The National Weather Service (originally known as the United States Weather Bureau) was founded through a joint congressional resolution signed by President Ulysses S. Grant.

February 10

2013: A violent tornado caused major damage in the town of Hattiesburg, Mississippi, including damage to several buildings on the University of Southern Mississippi campus.

February 11

1999: Cyclone Rona made landfall on the Cape York Peninsula, Queensland, Australia. Rainfall of up to 1,870 millimetres (74 in) caused historic flooding in the area that killed seven people.

Selected biography

Robert Simpson (left) and Cecil Gentry (right) at the National Hurricane Research Project Operations Base

Robert H. Simpson (November 19, 1912 – December 18, 2014) was an American meteorologist, hurricane specialist, first director of the National Hurricane Research Project (NHRP) from 1955 to 1959, and a former director (1967–1974) of the National Hurricane Center (NHC). He was the co-developer of the Saffir–Simpson Hurricane Scale with Herbert Saffir. His wife was Joanne Simpson. (Full article...)

Previously selected biographies: William Ferrel, John Dalton, 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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