Battle of Chustenahlah

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...)

Selected article

Three-day prediction of the path of Hurricane Rita
Three-day prediction of the path of Hurricane Rita

Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Human beings have attempted to predict the weather informally for millennia, and formally since at least the nineteenth century. Weather forecasts are made by collecting quantitative data about the current state of the atmosphere and using scientific understanding of atmospheric processes to project how the atmosphere will evolve.

Once an all human endeavor based mainly upon changes in barometric pressure, current weather conditions, and sky condition, forecast models are now used to determine future conditions. Human input is still required to pick the best possible forecast model to base the forecast upon, which involves pattern recognition skills, teleconnections, knowledge of model performance, and knowledge of model biases. The chaotic nature of the atmosphere, the massive computational power required to solve the equations that describe the atmosphere, error involved in measuring the initial conditions, and an incomplete understanding of atmospheric processes mean that forecasts become less accurate as the difference in current time and the time for which the forecast is being made (the range of the forecast) increases. The use of ensembles and model consensus help narrow the error and pick the most likely outcome.

There are a variety of end uses to weather forecasts. Weather warnings are important forecasts because they are used to protect life and property. Forecasts based on temperature and precipitation are important to agriculture, and therefore to traders within commodity markets. Temperature forecasts are used by utility companies to estimate demand over coming days. On an everyday basis, people use weather forecasts to determine what to wear on a given day. Since outdoor activities are severely curtailed by heavy rain, snow and the wind chill, forecasts can be used to plan activities around these events, and to plan ahead and survive them.

Recently selected articles: Climate of India, Subtropical cyclone, More...

More selected articles

Did you know (auto-generated) - show different entries

Selected image

Lightning strikes in the outskirts of Oradea, Romania, during a thunderstorm on August 17, 2005. This storm system went on to cause major flash floods over Southern Romania.


Recently selected pictures: Snow-swept trees, Low pressure

More selected pictures

More did you know...


...that the Flying river is the name given to the transport of water vapor from the Amazon rainforest to southern Brazil?

...that hurricane shutters are required for all homes in Florida unless impact-resistant glass is used?

...that the Joint Institute for Marine and Atmospheric Research is a combined weather and ocean research institute with the cooperation of the Office of Oceanic and Atmospheric Research and the University of Hawaiʻi?

...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?


Recent and ongoing weather

This week in weather history...

April 27

1980: Thai Airways Flight 231 stalled and crashed due to a downburst while flying through a thunderstorm on approach to Don Mueang International Airport, Bangkok, Thailand, killing 44 of 49 people on board.

April 28

2014: The second day of a multi-day tornado outbreak struck the Southeastern United States, bringing 50 tornadoes to 6 states that killed a total of 16 people.

April 29

1924: A tornado outbreak began which would kill at least 110 over the course of two days.

April 30: End of the Southern Hemisphere tropical cyclone seasons except for the Mauritius and Seychelles region

1054: The first known European tornado affected Rosdalla, near Kilbeggan, Ireland.

May 1

2012: The National Centers for Environmental Prediction in the United States replaced the Rapid Update Cycle (RUC) weather prediction model with the Rapid Refresh (RAP) model.

May 2

1982: The Weather Channel went on the air in the United States.

May 3: Start of National Hurricane Preparedness Week 2020

2000: The GOES 11 weather satellite was launched. Part of the Geostationary Operational Environmental Satellite program, GOES 11 was used as a backup satellite until it replaced the GOES 10 in 2006, and would provide weather forecasting data mainly for the Western United States and Pacific Ocean from 2006 until its retirement in 2011.

See a new, random set • Other days in history...

Selected biography

Portrait of John Park Finley in 1913

John Park Finley (April 11, 1854 – November 24, 1943) was an American meteorologist and Army Signal Service officer who was the first person to study tornadoes intensively and pioneer tornado forecasting. He also wrote the first known book on the subject as well as many other manuals and booklets, collected vast climatological data, set up a nationwide weather observer network, started one of the first private weather enterprises, and opened an early aviation weather school. (Full article...)

Previously selected biographies: Edward Norton Lorenz, Vilhelm Friman Koren Bjerknes, More...

More selected biographies

Related portals

Quality content

     Other candidates:

Subcategories

WikiProjects

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 Wikipedia'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!

Associated Wikimedia

The following Wikimedia Foundation sister projects provide more on this subject:

  • Commons
    Free media repository
  • Wikibooks
    Free textbooks and manuals
  • Wikidata
    Free knowledge base
  • Wikinews
    Free-content news
  • Wikiquote
    Collection of quotations
  • Wikisource
    Free-content library
  • Wikiversity
    Free learning tools
  • Wiktionary
    Dictionary and thesaurus

Other Portals

What you can do
Here are some tasks awaiting attention:

Purge server cache

source: https://en.wikipedia.org/wiki/Portal:Weather