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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The water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Since the water cycle is truly a "cycle," there is no beginning or end. Water can change states among liquid, vapor, and ice at various places in the water cycle, with these processes happening in the blink of an eye or over millions of years. Although the balance of water on Earth remains fairly constant over time, individual water molecules can come and go in a hurry.

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Did you know (auto-generated) - show different entries

... that an attempted British-Norwegian attack on the German battleship Tirpitz was abandoned after two Chariot manned torpedoes were lost due to bad weather?
... 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 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 Japanese actor Kouhei Higuchi prepared for his role on the television drama adaptation of My Personal Weatherman by learning from a weather forecaster?

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A mackerel sky over Edmonton, Alberta. Altocumulus clouds in this form indicate moisture and instability at high levels, the two main ingredients needed for precipitation. If the lower atmosphere is stable and no moist air moves in, the weather will most likely remain dry. However, moisture at lower levels combined with instability can lead to spectacular thunderstorms.

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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?

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Recent and ongoing weather

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This week in weather history...

June 6

1989: Typhoon Dot made landfall on the island of Samar, Philippines, causing widespread flooding and power outages.

June 7

1993: Levees began to be overtopped, marking the start of the Great Flood of 1993, one of the worst floods in US history.

June 8

1953: On the second day of a deadly three-day tornado outbreak, an F5 tornado killed 116 people in Flint, Michigan.

June 9

1998: A severe tropical cyclone made landfall in Gujarat, India, killing an estimated 10,000 people.

June 10

2005: A severe flood struck the town of Shalan in the Heilongjiang province of China, killing more than 100 people.

June 11

1979: A tropical depression formed over the Caribbean Sea south of Grand Cayman. The storm produced torrential rainfall over Jamaica, including up to 32 inches (810 mm) in Westmoreland Parish.

June 12

2004: Tropical Storm Chanthu made landfall in central Vietnam, killing 39 people.

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John Park Finley (April 11, 1854 – November 24, 1943) was an American meteorologist and Army Signal Service officer who was the first person to study tornadoes intensively and pioneer tornado forecasting. He also wrote the first known book on the subject as well as many other manuals and booklets, collected vast climatological data, set up a nationwide weather observer network, started one of the first private weather enterprises, and opened an early aviation weather school. (Full article...)

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Tropical Storm Ileana (2018) (Discussion)

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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!