Portal:Weather

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Weather is an all-encompassing term used to describe all of the many and varied phenomena that occur in the atmosphere of a planet at a given time. The term usually refers to the activity of these phenomena over short periods of hours or days, as opposed to the term climate, which refers to the average atmospheric conditions over longer periods of time. When used without qualification, "weather" is understood to be the weather of Earth.

Weather most often results from temperature differences from one place to another, caused by the Sun heating areas near the equator more than the poles, or by different areas of the Earth absorbing varying amounts of heat, due to differences in albedo, moisture, and cloud cover. Surface temperature differences in turn cause pressure differences. A hot surface heats the air above it and the air expands, lowering the air pressure. The resulting pressure gradient accelerates the air from high to low pressure, creating wind, and Earth's rotation causes curvature of the flow via the Coriolis effect. These simple systems can interact, producing more complex systems, and thus other weather phenomena.

The strong temperature contrast between polar and tropical air gives rise to the jet stream. Most weather phenomena in the mid-latitudes are caused by instabilities of the jet stream flow (see baroclinity) or by weather fronts. Weather systems in the tropics are caused by different processes, such as monsoons or organized thunderstorm systems.

Because the Earth's axis is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. In June the Northern Hemisphere is tilted towards the sun, while in December it is tilted away, causing yearly changes in the weather known as seasons. In the mid-latitudes, winter weather often includes snow and sleet, while in both the mid-latitudes and most of the tropics, tropical cyclones form in the summer and autumn. Almost all weather phenomena can occur year-round on different parts of the planet, including snow, rain, lightning, and, more rarely, hail and tornadoes.

Related portals: Earth sciences (Atmosphere  · Atmospheric Sciences)  · Tropical cyclones Featured article  · Disasters  · Water

Selected picture

DustStormInSpearmanTexas19350414.jpg

This dust storm occurred around Spearman, Texas on April 14, 1935. This was in the heart of the Dust Bowl, a period of severe dust storms and drought, which contributed to the Great Depression in the United States.

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Selected article

Hurricane Vince eye 2005.jpg
Hurricane Vince was an unusual hurricane which developed in the northeastern Atlantic basin. Forming in October during the 2005 Atlantic hurricane season, the waters over which it developed were considered too cold for tropical development. Vince was the 20th named tropical cyclone and 12th hurricane of the extremely active season. Vince developed from a non-tropical system on October 8, becoming a subtropical storm southeast of the Azores. The National Hurricane Center (NHC) did not officially name the storm until the next day, shortly before Vince became a hurricane. The storm weakened at sea and, on October 11, made landfall on the Iberian Peninsula as a tropical depression. Vince was the first tropical system to do so since the 1842 Spain hurricane. It dissipated over Spain, bringing much needed rain to the region, and its remnants passed into the Mediterranean Sea...

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Did you know...

...that Hurricane Debbie is the only known tropical cyclone ever to strike Ireland?

...that the Tempest Prognosticator, one of the earliest attempts at a weather prediction device, employed live leeches in its operation?

...that eyewall replacement cycles are among the biggest challenges in forecasting tropical cyclone intensity?

...that the Braer Storm of January 1993 is likely the strongest extratropical cyclone ever recorded in the north Atlantic Ocean?

...that in medieval lore, Tempestarii are magicians with the power to control the weather?

...that the omega equation is essential to numerical weather prediction?

Recent and ongoing weather

This week in weather history...

March 20

2006: Cyclone Larry made landfall near Innisfail, Queensland, resulting in almost $1 billion (USD) in damage.

March 21

1932: A deadly tornado outbreak killed 330 people in the Southern United States, including 268 deaths in Alabama, the most in that state's history.

March 22

1999: Cyclone Vance made landfall near Exmouth, Western Australia, where an Australian-record wind gust of 267 kilometers per hour (166 mph) was recorded.

March 23: World Meteorological Day

1913: A tornado struck the city of Omaha, Nebraska on Easter Sunday, killing more than 100 people.

March 24

Portal:Weather/On this day list/March 24/0

March 25

1913: The worst flood in Ohio history began as levees protecting downtown Dayton failed.

March 26

2009: Severe flooding exceeded 40 feet at Fargo, North Dakota, breaking a record set in 1897.

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Other days in history...

Selected biography

Portrait of John Dalton FRS

John Dalton FRS (6 September 1766 – 27 July 1844) was an English chemist, meteorologist and physicist. He is best known for his research into colour blindness and his pioneering work in the development of modern atomic theory, which came out of his initial interest in meteorology and atmospheric chemistry. He aided in the rediscovery of George Hadley's theory of atmospheric circulation: the Hadley cell, and published a book, Meteorological Observations and Essays, where he speculated on the nature of the atmosphere, its motion, and its chemistry.

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Categories

Weather: Meteorology | Atmosphere | Basic meteorological concepts and phenomena | Climate | Clouds | Cyclones | Floods | Precipitation| Seasons | Severe weather and convection | Snow | Storms | Tornadoes | Tropical cyclones | Weather events | Weather lore | Weather hazards | Weather modification | Weather prediction | Weather warnings and advisories| Winds

Wikiprojects

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 Wikipdia's coverage of tropical cyclones.

WikiProject Non-tropical storms is a collaborative project to improve articles related to winter storms, wind storms, and extratropical weather.

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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