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...)
Hurricane Dean was the strongest tropical cyclone of the 2007 Atlantic hurricane season. A Cape Verde-type hurricane that formed on August 13, 2007, Dean took a west-northwest path from the eastern Atlantic Ocean through the Saint Lucia Channel and into the Caribbean. It strengthened into a major hurricane, reaching Category 5 status on the Saffir–Simpson hurricane scale before passing just south of Jamaica on August 20. The storm made landfall on the Yucatán Peninsula on August 21 as a powerful Category 5 storm. It crossed the peninsula and emerged into the Bay of Campeche as a weaker storm, but still at hurricane strength. It intensified briefly before making a second landfall near Tecolutla, Mexico, on August 22. Dean drifted northwest, weakening into a remnant low which dissipated over the southwestern United States.
The hurricane's intense winds, waves, rains and storm surge were responsible for at least 45 deaths across ten countries, and caused estimated damages ofUS$1.5 billion. Dean's path through the Caribbean devastated crops, particularly those of Martinique and Jamaica. Upon reaching Mexico, Hurricane Dean was a Category 5 storm—the third-most intense Atlantic hurricane at landfall in recorded history. However, it missed major population centers, so it caused no deaths and less damage than its passage through the Caribbean islands as a Category 2 storm.
Dean was the first hurricane to make landfall in the Atlantic basin at Category 5 intensity in 15 years; the last storm to do so was Hurricane Andrew on August 24, 1992. Dean's landfall was far less damaging than Andrew's, but its long swath of damage earned its name retirement from the World Meteorological Organization's Atlantic hurricane naming lists.
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View of the eyewall of Hurricane Katrina taken on August 28, 2005, as seen from a NOAA WP-3D Orion hurricane hunter aircraft before the storm made landfall on the United States Gulf Coast.
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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?
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...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?
2010: Cyclone Oli struck parts of French Polynesia, including Tahiti. One person was killed on the island of Tubuai.
2002: Cyclone Chris, one of the strongest tropical cyclones to strike Western Australia on record, reached peak intensity just hours before landfall.
1996: Heavy rain and warm temperatures started several days of significant flooding in the Pacific Northwest, resulting in more than $500 million in damage.
2002: A strong windstorm known as the South Valley Surprise struck the Pacific Northwest with no warning due to the rapid deepening of the storm, causing major tree damage across the area.
1962: The TIROS-4 weather satellite was launched from Cape Canaveral Air Force Station, Florida.
1969: A severe nor'easter brought unexpectedly heavy snow to the Northeastern United States, bringing over 40 inches (100 cm) of snow in some places and killing 94 people.
1972: A week-long blizzard came to an end in the country of Iran, leaving around 4,000 people dead.
Clement Lindley Wragge (18 September 1852 – 10 December 1922) was a meteorologist born in Stourbridge, Worcestershire, England, but moved to Oakamoor, Staffordshire as a child. He set up the Wragge Museum in Stafford following a trip around the world. He was a Fellow of the Royal Geographical Society and in 1879 was elected Fellow of the Royal Meteorological Society in London. To the end of his life, he was interested in theosophy and spiritualism. In 1908, during a tour of India, he met with Mirza Ghulam Ahmad of Qadian, the founder of the Ahmadiyya movement in Islam who had claimed to be the Mahdi, the messianic redeemer awaited by Muslims. Sir Arthur Conan Doyle sought him out in New Zealand to ask for his views on spiritualism before writing The Wanderings of a Spiritualist in 1921. After training in law, Wragge became a meteorologist, his accomplishments in the field including winning the Scottish Meteorological Society's Gold Medal and years later starting the trend of using people's names for cyclones. He travelled widely, giving lectures in London and India, and in his later years was an authority on Australia, India and the Pacific Islands. (Full article...)
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