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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Cleveland blizzard 1913, poles down.png
The Great Lakes Storm of 1913 was a blizzard which produced hurricane-force winds that devastated the Great Lakes basin in the United States Midwest and the Canadian province of Ontario from November 7, 1913, to November 10, 1913.

The deadliest and most destructive natural disaster to ever hit the lakes, the storm killed over 250 people, destroyed 19 ships, and stranded 19 others. It produced 6-foot drifts of snow in the surrounding land areas, snapped power poles, and paralyzed many areas for days, especially the area around Cleveland, Ohio.

The financial loss in water-bound vessels alone was nearly $5 million, or about $100 million in present-day adjusted dollars. The large loss of cargo, including coal, iron ore, and grain, meant short-term rising prices for consumer products throughout North America.

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F5 tornado Elie Manitoba 2007.jpg

This tornado struck the town of Elie, Manitoba on June 22, 2007. It was the first tornado outside the United States to be rated F5 on the Fujita Scale, the most severe level of tornado damage.

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More did you know...

...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?

...that a cryoseism is a sudden ground or glacier movement that can occur due to water freezing or ice cracking after drastic temperature changes?

...that BUFR is a binary data format standardized by the World Meteorological Organization for storing observation data from weather stations and weather satellites?

...that the Northwest Weather and Avalanche Center issues weather forecasts for conditions that can cause avalanches in the mountains of western Washington and northwestern Oregon?

Recent and ongoing weather

This week in weather history...

June 29

1998: The Corn Belt Derecho produced wind gusts as high as 123 mph (198 km/h) as well as dozens of tornadoes in its rampage across eight states in the Midwest and Ohio Valley, killing one person and injuring 174.

June 30

1912: The Regina Cyclone killed 28 people in Regina, Saskatchewan, making it the deadliest tornado in Canadian history.

July 1

1992: The national meteorological service of New Zealand, known as the MetService, was established as a state-owned enterprise.

July 2

1965: TIROS-10, the final weather satellite of the original TIROS program, was launched from Cape Canaveral Air Force Station, Florida.

July 3

1996: Tropical Storm Cristina made landfall near Puerto Ángel, the third tropical cyclone to strike southern Mexico in 10 days.

July 4

1999: A severe derecho produced 90 miles per hour (145 km/h) winds that downed 25 million trees in the Boundary Waters Canoe Area Wilderness of northeastern Minnesota.

July 5

1805: Robert FitzRoy, captain of the HMS Beagle and a pioneering British meteorologist, was born in Suffolk, England.

Selected biography

Portrait of William Ferrel

William Ferrel (January 29, 1817 – September 18, 1891) was an American meteorologist who developed theories that explained the mid-latitude atmospheric circulation cell in detail, and it is after him that the Ferrel cell is named. (Full article...)

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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 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 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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