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  · Atmospheric Sciences)  · Tropical cyclones  · Disasters  · Water

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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
  • September 2: Hurricane Earl threatens eastern US: Live updates
  • August 24: Atlantic storm Danielle strengthens to hurricane force
  • August 23: Tropical Storm Danielle forms in Atlantic Ocean
  • August 11: Several injured at campground in Maine as storm topples trees
  • August 11: Flash floods kill over a hundred in India, 500 missing
• 2010 Atlantic hurricane season
• 2008–09 South-West Indian Ocean cyclone season
• 2010 Pacific typhoon season
• Tornadoes of 2010
• Winter storms of 2008–09

This week in weather history...

August 31

1971: Hurricane Lily struck western Mexico, causing devastating flooding in Puerto Vallarta.

September 1

1984: Typhoon Ike struck Siargao Island in the Philippines, killing more than 1,300 people and leaving more than 200,000 homeless.

September 2

1935: The Labor Day Hurricane, the strongest hurricane ever to strike the United States, passed over the Florida Keys, killing as many as 600 people.

September 3

1976: A Venezuelan Air Force flight crashed while attempting to land on Terceira Island, Azores, during Hurricane Emmy, killing all 68 aboard.

September 4

1933: The strongest hurricane to strike the United States during the hyperactive 1933 Atlantic hurricane season made landfall near Jupiter, Florida.

September 5

2003: Hurricane Fabian made landfall on Bermuda as a Category 3 hurricane, the strongest to strike the island in 40 years.

September 6

1986: Typhoon Wayne dissipated over Vietnam 22 days after it formed, making it the longest-lived tropical cyclone on record in the Western Pacific Ocean.

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Quality content

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.

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