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Probability Of Precipitation
Definitions U.S. National Weather Service According to the U.S. National Weather Service (NWS), PoP is the probability of exceedance that more than of precipitation will fall in a single spot, averaged over the forecast area. The PoP measure is meaningless unless it is associated with a period of time. NWS forecasts commonly use PoP defined over 12-hour periods (PoP12), though 6-hour periods (PoP6) and other measures are also published. A "daytime" PoP12 means from 6 am to 6 pm. The NWS also provides hourly forecasts. The hourly PoP can be similar to the daily PoP and vary little, or it can vary dramatically. An example of an event where the hourly PoPs are not independent is a hurricane. In that case, there may be a 1 in 5 chance of the hurricane hitting a given stretch of coast, but if it does arrive there will be rain for several hours. Other US forecasters AccuWeather's definition is based on the probability at the forecast area's official rain gauge. There is also a pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Weather Service
The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the purposes of protection, safety, and general information. It is a part of the National Oceanic and Atmospheric Administration (NOAA) branch of the Department of Commerce, and is headquartered in Silver Spring, Maryland, within the Washington metropolitan area. The agency was known as the United States Weather Bureau from 1890 until it adopted its current name in 1970. The NWS performs its primary task through a collection of national and regional centers, and 122 local Weather Forecast Offices (WFOs). As the NWS is an agency of the U.S. federal government, most of its products are in the public domain and available free of charge. History Calls for the creation of a government weather bureau began as early as 1844, when the electric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Probability Of Exceedance
The frequency of exceedance, sometimes called the annual rate of exceedance, is the frequency with which a random process exceeds some critical value. Typically, the critical value is far from the mean. It is usually defined in terms of the number of peaks of the random process that are outside the boundary. It has applications related to predicting extreme events, such as major earthquakes and floods. Definition The frequency of exceedance is the number of times a stochastic process exceeds some critical value, usually a critical value far from the process' mean, per unit time. Counting exceedance of the critical value can be accomplished either by counting peaks of the process that exceed the critical value or by counting upcrossings of the critical value, where an ''upcrossing'' is an event where the instantaneous value of the process crosses the critical value with positive slope. This article assumes the two methods of counting exceedance are equivalent and that the process ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AccuWeather
AccuWeather Inc. is an American media company that provides commercial weather forecasting services worldwide. AccuWeather was founded in 1962 by Joel N. Myers, then a Pennsylvania State University graduate student working on a master's degree in meteorology. His first customer was a gas company in Pennsylvania. While running his company, Myers also worked as a member of Penn State's meteorology faculty. The company adopted the name "AccuWeather" in 1971. AccuWeather is headquartered in Ferguson Township, just outside of State College, Pennsylvania, with offices at 80 Pine Street in Manhattan's Financial District in addition to Wichita, Kansas, and Oklahoma City, Oklahoma. Internationally, AccuWeather has offices in Montreal, Tokyo, Beijing, Seoul, and Mumbai. Company profile AccuWeather provides weather forecasts and warnings and additional weather products and services, with clients worldwide in media, business, and government, including more than half of the Fortun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rain Gauge
A rain gauge (also known as udometer, pluvia metior, pluviometer, ombrometer, and hyetometer) is an instrument used by meteorologists and hydrologists to gather and measure the amount of liquid precipitation over a predefined area, over a period of time. It is used for determining the depth of precipitation (usually in mm) that occurs over a unit area and thus measuring rainfall amount. History The first known rainfall records were kept by the Ancient Greeks, at around 500 BCE. People living in India began to record rainfall in 400 BCE Ian Strangeways, A History of rain gauges, TerraData, 2010 The readings were correlated against expected growth. In the Arthashastra, used for example in Magadha, precise standards were set as to grain production. Each of the state storehouses were equipped with a rain gauge to classify land for taxation purposes. In 1247, the Song Chinese mathematician and inventor Qin Jiushao invented Tianchi basin rain and snow gauges to reference rain, snowf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five major unincorporated territories, nine United States Minor Outlying Islands, Minor Outlying Islands, and 326 Indian reservations. The United States is also in Compact of Free Association, free association with three Oceania, Pacific Island Sovereign state, sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Palau, Republic of Palau. It is the world's List of countries and dependencies by area, third-largest country by both land and total area. It shares land borders Canada–United States border, with Canada to its north and Mexico–United States border, with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Weather Channel
The Weather Channel (TWC) is an American pay television channel owned by Weather Group, LLC, a subsidiary of Allen Media Group. The channel's headquarters are in Atlanta, Georgia. Launched on May 2, 1982, the channel broadcasts weather forecasts and weather-related news and analysis, along with documentaries and entertainment programming related to weather. A sister network, Weatherscan, was a digital cable and satellite service that offered 24-hour automated local forecasts and radar imagery. Weatherscan was officially shut down on December 9, 2022. The Weather Channel also produces outsourced weathercasts, notably for CBS News and RFD-TV. The Weather Channel was a subsidiary of the Weather Company until the latter was bought by IBM in 2016. The Weather Channel licenses its weather data from IBM. History The Weather Channel was founded on July 18, 1980,USPTO filings: First Use (not First Use in Commerce date on various filings, including filing w/ serial number 73369821) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wet Bias
Wet bias is the phenomenon whereby some weather forecasters report an overestimated and exaggerated probability of precipitation to increase the usefulness and actionability of their forecast. The Weather Channel has been empirically shown, and has also admitted, to having a wet bias in the case of low probability of precipitation (for instance, a 5% probability may be reported as a 20% probability) but not at high probabilities of precipitation (so a 60% probability will be reported as a 60% probability). Some local television stations have been shown as having significantly greater wet bias, often reporting a 100% probability of precipitation in cases where it rains only 70% of the time. Discovery In 2002, Eric Floehr, a computer science graduate of the Ohio State University, started collecting historical data of weather forecasts made by the National Weather Service (NWS), The Weather Channel (TWC), and AccuWeather for the United States, and collected the data on a website calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environment Canada
Environment and Climate Change Canada (ECCC; french: Environnement et Changement climatique Canada),Environment and Climate Change Canada is the applied title under the Federal Identity Program; the legal title is Department of the Environment (). is the department of the Government of Canada responsible for coordinating environmental policies and programs, as well as preserving and enhancing the natural environment and renewable resources. It is also colloquially known by its former name, Environment Canada (EC; french: Environnement Canada, links=no). The minister of environment and climate change has been Steven Guilbeault since October 26, 2021; Environment and Climate Change Canada supports the minister's mandate to: "preserve and enhance the quality of the natural environment, including water, air, soil, flora and fauna; conserve Canada's renewable resources; conserve and protect Canada's water resources; forecast daily weather conditions and warnings, and provide detail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Met Office
The Meteorological Office, abbreviated as the Met Office, is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy and is led by CEO Penelope Endersby, who took on the role as Chief Executive in December 2018 and is the first woman to do so. The Met Office makes meteorological predictions across all timescales from weather forecasts to climate change. History The Met Office was established on 1 August 1854 as a small department within the Board of Trade under Vice Admiral Robert FitzRoy as a service to mariners. The loss of the passenger vessel, the ''Royal Charter'', and 459 lives off the coast of Anglesey in a violent storm in October 1859 led to the first gale warning service. FitzRoy established a network of 15 coastal stations from which visual gale warnings could be provided for ships at sea. The new electric telegraph enabled rapid dissemination of warnings an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plain English Campaign
The Plain English Campaign (PEC) is a commercial editing and training firm based in the United Kingdom. Founded in 1979 by Chrissie Maher, the company is a world leader in plain-language advocacy, working to persuade organisations in the UK and abroad to communicate with the public in plain language. Maher was awarded the Order of the British Empire in 1994 for her services to plain communication. In 1990, PEC created the Crystal Mark, its seal of approval. This is a symbol printed on documents that it considers to be as clear as possible for the intended audience. The symbol appears on over 20,000 documents worldwide. They also give out the annual Foot in Mouth Award for "a baffling comment by a public figure" and the Golden Bull Award for "the worst examples of written tripe". Notable winners of the Foot in Mouth Award include Donald Trump, George W. Bush, Gordon Brown, Richard Gere, and Donald Rumsfeld. PEC has worked all over the world for companies and organisations inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantitative Precipitation Forecast
The quantitative precipitation forecast (abbreviated QPF) is the expected amount of melted precipitation accumulated over a specified time period over a specified area. A QPF will be created when precipitation amounts reaching a minimum threshold are expected during the forecast's valid period. Valid periods of precipitation forecasts are normally synoptic hours such as 00:00, 06:00, 12:00 and 18:00 GMT. Terrain is considered in QPFs by use of topography or based upon climatological precipitation patterns from observations with fine detail. Starting in the mid-to-late 1990s, QPFs were used within hydrologic forecast models to simulate impact to rivers throughout the United States. Forecast models show significant sensitivity to humidity levels within the planetary boundary layer, or in the lowest levels of the atmosphere, which decreases with height. QPF can be generated on a quantitative, forecasting amounts, or a qualitative, forecasting the probability of a specific am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numerical Climate And Weather Models
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Numerical may refer to: * Number * Numerical digit * Numerical analysis Numerical analysis is the study of algorithms that use numerical approximation (as opposed to symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics). It is the study of numerical methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
