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.
A pickup truck was wrapped around this utility pole by the extreme winds from the Moore, Oklahoma tornado which occurred on 1999-05-03. The truck was then pummelled by winds which exceeded 200 mph (320 km/h), stripping most of the sheet metal off the truck. The F5 tornado was one of the most severe ever observed, and destroyed more than 1500 homes, killing 36 people.
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A jet stream is a fast flowing, relatively narrow air current found at the tropopause, the transition between the troposphere (where temperature decreases with height) and the stratosphere (where temperature increases with height). Jet streams are typically located at 10-15 kilometers above the surface of the Earth. They form near boundaries of adjacent air masses with significant differences in temperature, such as the polar region and the warmer air to the south. The path of the jet typically has a meandering shape, and these meanders known as Rossby waves. Rossby waves propagate westward with respect to the flow in which they are embedded, which translates to a slower eastward migration across the globe than smaller scale short wave troughs. The major jet streams are westerly winds (flowing west to east) in the Northern Hemisphere.
During the summer, low-level easterly jets can form in tropical regions. A southerly low level jet in the Great Plains of North America helps fuel overnight thunderstorm activity, normally in the form of mesoscale convective systems. A similar northerly low-level jet can form across Australia, instigated by cut-off lows which develop across southwest portions of the country.
Meteorologists use the location of the jet stream as an aid in weather forecasting. The main commercial use of the jet stream is during airline travel, as flying long distances along the jet stream can cut hours off a long distance trip. One type of clear-air turbulence is found in the jet stream's vicinity, which can be a hazard to aircraft. One future benefit of the jet stream could be to augment power generation within the next 10 to 20 years, if technological hurdles can be overcome.
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...that the 1984 Yaroslavl tornado killed at least 400 people north of Moscow, Russia?
...that nearly 10 years before the 2008 Atlanta Tornado, the Dunwoody Tornado caused significant damage just outside the city limits?
...that the Lorain-Sandusky tornado was both the deadliest tornado and part of the deadliest tornado outbreak in Ohio history?
...that micrometeorology is a study of small-scale weather phenomena, which takes into account such small influences as heat transfer between the ground and air, changes in atmospheric gasses near the surface, and absorption and reflection of solar radiation?
...that teleconnection is a term for climate anomalies which appear to be linked at great distances?
...that the Spaceflight Meteorology Group is a unit of the National Weather Service which provides weather forecasts solely for human spaceflights by the National Aeronautics and Space Administration (NASA).
- Wikinews weather portal
- June 9: Lightning strikes park in Connecticut killing 1, injuring 4
- May 31: First storm of Atlantic hurricane season forms off coast of Belize
- May 27: Long March rocket launches first Fengyun-3 weather satellite
- May 23: Tornado kills one and injures 100 in northern Colorado
- May 11: Tornadoes in central US kill nearly two dozen people
- Winter storms of 2007-08
- 2007-08 South-West Indian Ocean cyclone season
- 2008 Pacific typhoon season
- Tornadoes of 2008
June 8
1966: A tornado, one of the costliest in history, tracked across the city of Topeka, Kansas.
June 9
1953: The day after a tornado affected the city of Flint, Michigan, another tornado plowed through the city of Worcester, Massachusetts.
June 12
1899: The New Richmond Tornado completely destroyed the village of New Richmond, Wisconsin.
June 15
1991: Typhoon Yunya struck the island of Luzon in the Philippines, the same day that Mount Pinatubo erupted catastrophically.
June 16
1992: One of the largest tornado outbreaks ever produced 123 tornadoes, including one F5, but incredibly killed only one person.
Anders Celsius (November 27, 1701 – April 25, 1744) was a Swedish astronomer who is best known for his pursuit to develop a standardized temperature scale. He determined that the melting point and boiling point of water are constant regardless of latitude, and the boiling point of water is dependant on elevation.
In 1742 he proposed a temperature scale which now bears his name, the Celsius scale, which is used worldwide for meteorological observations around the world. In his scale, the boiling point of water was 0 degrees and the freezing point was 100, while the modern Celsius scale is the reverse of this. In addition to his temperature work, he was an avid observer of the aurora borealis and participated in an expedition to measure an arc of the meridian in northern Sweden.
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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
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.
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