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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In meteorology, precipitation is a term for any product of the condensation of atmospheric water vapour that is deposited on the Earth's surface. It occurs when the atmosphere, becomes saturated with water vapour and the water condenses, falling out of solution. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapour to the air. Precipitation forms via collision with other rain drops or ice crystals within a cloud.

Precipitation that reaches the surface of the earth can occur in many different forms, including rain, freezing rain, drizzle, ice needles, snow, ice pellets or sleet, graupel and hail. While snow and ice pellets require temperatures to be near or below freezing at the surface, hail can occur during much warmer temperature regimes due to the process of its formation. Precipitation also occurs on other celestial bodies—including snow on Mars and a sulfuric acid rain on Venus—though both of these evaporate before reaching the surface.

Moisture overriding associated with weather fronts is a major method of precipitation production. If enough moisture and upward motion is present, precipitation falls from convective clouds such as cumulonimbus and can organize into narrow rainbands. Precipitation can also form due to forced ascent up the windward side of a mountain or mountain range. Precipitation is a major component of the water cycle, and is responsible for depositing essentially all of the fresh water on the planet. Approximately 505,000 km³ (121,000 cu mi) of water falls as precipitation each year; 398,000 km³ (95,000 cu mi) of it over the oceans.

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

... 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?
... that after Irish post office clerk Maureen Flavin Sweeney reported worsening weather conditions, Dwight D. Eisenhower agreed to postpone D-Day by 24 hours?
... that weather whiplash is the phenomenon of rapid swings between extremes of weather conditions?
... that extreme event attribution estimates how much climate change causes weather events, such as the 2021 Western North America heat wave?
... that in the 1980s, "Sherman Bonner, The Human Thermometer" presented the weather on an Arkansas TV station?

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Lightning strikes in the outskirts of Oradea, Romania, during a thunderstorm on August 17, 2005. This storm system went on to cause major flash floods over Southern Romania.

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...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...

May 13

1980: A strong tornado devastated downtown Kalamazoo, Michigan.

May 14

1991: The NOAA-12 weather satellite was launched into a polar orbit from Vandenberg Air Force Base, California.

May 15: Start of the East Pacific hurricane season and end of the Mauritius and Seychelles cyclone season

1896: The first tornado of a deadly sequence of tornado outbreaks killed 73 people in North-Central Texas.

May 16

2004: Typhoon Nida reached category 5 intensity just east of the Philippines.

May 17

2003: Ratnapura, Sri Lanka, recorded 366.1 millimetres (14.41 in) of rain in just 18 hours from a tropical cyclone that caused some of the worst flooding on the island in its history.

May 18

1986: Cyclone Namu, the worst tropical cyclone ever to affect the Solomon Islands, killed 150 people as it passed through the island nation.

May 19

2018: Cyclone Sagar struck northwestern Somalia, killing 56 people in three countries. It was the strongest tropical cyclone on record to strike Somalia.

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Sir William Napier Shaw FRS (4 March 1854 – 23 March 1945) was a British meteorologist. He introduced the tephigram, a diagram for evaluating convective instability in the atmosphere. He also served as president of the International Meteorological Committee and Royal Meteorological Society. (Full article...)

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Hurricane Isabel

Hurricane Isabel eye

1900 Galveston Hurricane

Hurricane Isabel

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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!