Portal:Weather
The Weather Portal
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 
· Disasters · Water
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Ground fog is a type of fog formed by the ground cooling a warm layer of air near the surface to its dew point. This scene is in East Frisia, Germany just after sunrise.
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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 Sea. 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 of US$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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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 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
- Wikinews weather portal
- April 30: St. Louis storm uproots tent; one dead, several injured
- April 25: Disposal of fracking wastewater poses potential environmental problems
- April 15: Wikinews Shorts: April 14, 2012
- March 30: Report indicates continued severe weather problems still looming
- March 17: Indiana teen softball player recovering after lighting strike
- 2012 Atlantic hurricane season
- 2012 Pacific typhoon season
- Tornadoes of 2012
This week in weather history...
May 27
1997: The Jarrell tornado completely wiped out the Double Creek Estates, killing 27 of 131 residents.
May 28
1959: Tropical Storm Arlene formed over the northern Gulf of Mexico.
May 29
2008: Tropical Storm Alma formed just off the coast of Costa Rica at 86.5º W, the easternmost Pacific tropical cyclone on record. Alma was also the only known tropical cyclone to strike the Pacific coast of Nicaragua.
May 30
1998: After a supercell spawned an F4 tornado that nearly wiped out the town of Spencer, South Dakota, the storms organized into a destructive derecho that tracked over 1,000 miles (1,609 km) across the southern Great Lakes region of the United States and Canada.
May 31
1889: The Johnstown Flood, caused by days of heavy rains which led to the failure of the South Fork Dam, killed more than 2,000 people in Johnstown, Pennsylvania.
June 1: Start of the Central Pacific and Atlantic hurricane seasons
1999: American Airlines Flight 1420 overran the runway in a severe thunderstorm, killing 10 passengers and the pilot.
2011: An EF3 tornado killed 3 people in south-central Massachusetts.
June 2
1990: Thirty-seven tornadoes struck the US state of Indiana, the most ever recorded in that state in a single day.
Selected biography
Edward Norton Lorenz (May 23, 1917 – April 16, 2008) was an American mathematician and meteorologist, and a pioneer of chaos theory. He discovered the strange attractor notion and coined the term butterfly effect. Lorenz was born in West Hartford, Connecticut. He studied mathematics at both Dartmouth College in New Hampshire and Harvard University in Cambridge, Massachusetts. During World War II, he served as a weather forecaster for the United States Army Air Corps. After his return from the war, he decided to study meteorology. Lorenz earned two degrees in the area from the Massachusetts Institute of Technology where he later was a professor for many years.
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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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