Question: What is the name of a commercial weather service that provides real-time weather information reported by personal weather stations that have access to this international website?
Context: The North Atlantic weather war occurred during World War II.  The allies (Britain in particular) and Germany vied for access to reliable weather data in the North Atlantic and Arctic Oceans and sought to deny the other weather information.  Meteorological data was important as it affected military planning and the routing of ships and convoys.  In some circumstances, visibility was necessary (photographic reconnaissance and bombing raids) and in others concealment (keeping ship movements secret or suppressing enemy air activity).  D-day planning was greatly affected by weather forecasting; it was delayed by one day in the expectation that a storm would blow out and sea conditions would be acceptable.  British sources of data included ships at sea and the weather stations at Valentia Observatory and Blacksod Point, in neutral Ireland.  German use of weather ships also exposed their secret Enigma codes. DUATS, or Direct User Access Terminal Service is a weather information and flight plan processing service contracted by the Federal Aviation Administration (FAA) for use by United States civil pilots and other authorized users.  The DUAT Service is a telephone- and Internet-based system which allows the pilot to use a personal computer for access to a Federal Aviation Administration (FAA) database to obtain weather and aeronautical information and to file, amend, and cancel domestic IFR and VFR flight plans.  The DUAT Service provides direct access to weather information via a National Airspace System (NAS) Data Interchange Network II (NADIN-II) interface to the Weather Message Switching Center Replacement (WMSCR) System and the Air traffic control (ATC) Facilities for filing flight plans.  The pilot users can interface the DUAT Services via the FTS-2001 toll free telephone numbers or via an Internet Interface into the Contractor's Facility. National Weather Service Lincoln, Illinois also known as National Weather Service Central Illinois is a weather forecast office responsible for monitoring weather conditions for 35 counties in Central and Southeastern Illinois.  The Central Illinois office initially consisted of two forecast offices in Peoria and Springfield until the current location in Lincoln became the sole local forecast office in 1995.  Federal meteorology offices and stations in the region date back to the 19th century when the Army Signal Service began taking weather observations using weather equipment at the Springer Building in Springfield.  Since that time the presence of the National Weather Service greatly increased with the instillation of new weather radars, stations and forecast offices.  The current office in Lincoln maintains a WSR-88D (NEXRAD) radar system, and Advanced Weather Interactive Processing System (AWIPS) that greatly improve forecasting in the region.  Lincoln is in charge of weather forecasts, warnings and local statements as well as aviation weather. Weather Underground is a commercial weather service providing real-time weather information via the Internet.  Weather Underground provides weather reports for most major cities across the world on its website, as well as local weather reports for newspapers and websites.  Its information comes from the National Weather Service (NWS), and over 250,000 personal weather stations (PWS).  The website is available in many languages, and customers can access an ad-free version of the site with additional features for an annual fee.  Weather Underground is owned by The Weather Company, a subsidiary of IBM. OpenWeatherMap is an online service that provides weather data, including current weather data, forecasts, and historical data to the developers of web services and mobile applications.  For data sources, it utilizes meteorological broadcast services, raw data from airport weather stations, raw data from radar stations, and raw data from other official weather stations.  All data is processed by OpenWeatherMap in a way that it attempts to provide accurate online weather forecast data and weather maps, such as those for clouds or precipitation.  Beyond that, the service is focused on the social aspect by involving weather station owners in connecting to the service and thereby increasing weather data accuracy.  The ideology is inspired by OpenStreetMap and Wikipedia that make information free and available for everybody.  It uses OpenStreetMap for display of weather maps. The National Weather Service Duties Act of 2005 was a legislative proposal forwarded in April 2005 by United States Senator Rick Santorum (R-PA) to curtail perceived government competition with commercial weather services from the National Weather Service.  Though the wording of the bill was generally considered unclear, the general consensus among observers was that its effect would be to eliminate public dissemination of National Weather Service data and forecasts except in case of severe weather alerts.  The bill attracted no cosponsors in the Senate and eventually died in committee, and was roundly criticized by the general public for threatening to move taxpayer-funded data (currently made available for free) to commercial for-profit channels (i.e. behind a pay wall).  The bill had very few supporters outside the commercial weather industry. National Weather Service Chicago, currently based in Romeoville, Illinois, is a weather forecast office responsible for monitoring weather conditions for 23 counties in Northern Illinois, the Chicago metropolitan area and Northwest Indiana.  The Army Signal Service established the first federal weather office in the region in Chicago on October 15, 1870.  During May 1894 the Chicago Weather Bureau was given a new forecast area extending from the Great Lakes region all the way to the Rocky Mountains.  The current National Weather Service Chicago is located in Romeoville and is in charge of issuing local forecasts and weather warnings for the Chicago area.  It is one of only two National Weather Service offices in Illinois, the other being National Weather Service Central Illinois in Lincoln, Illinois.  The National Weather Service Chicago forecast office is located adjacent to the Lewis University Airport in Romeoville, Illinois. The Citizen Weather Observer Program (CWOP) is a network of privately owned electronic weather stations concentrated in the United States but also located in over 150 countries.  Network participation allows volunteers with computerized weather stations to send automated surface weather observations to the National Weather Service (NWS) by way of the Meteorological Assimilation Data Ingest System (MADIS).  This data is then used by the Rapid Refresh (RAP) forecast model to produce short term forecasts (3 to 12 hours into the future) of conditions across the contiguous United States.  Observations are also redistributed to the public. Surface weather observations are the fundamental data used for safety as well as climatological reasons to forecast weather and issue warnings worldwide.  They can be taken manually, by a weather observer, by computer through the use of automated weather stations, or in a hybrid scheme using weather observers to augment the otherwise automated weather station.  The ICAO defines the International Standard Atmosphere (ISA), which is the model of the standard variation of pressure, temperature, density, and viscosity with altitude in the Earth's atmosphere, and is used to reduce a station pressure to sea level pressure.  Airport observations can be transmitted worldwide through the use of the METAR observing code.  Personal weather stations taking automated observations can transmit their data to the United States mesonet through the Citizen Weather Observer Program (CWOP), the UK Met Office through their Weather Observations Website (WOW), or internationally through the Weather Underground Internet site.  A thirty-year average of a location's weather observations is traditionally used to determine the station's climate. A Road Weather Information System (RWIS) comprises automatic weather stations (technically referred to as Environmental Sensor Stations (ESS)) in the field, a communication system for data transfer, and central systems to collect field data from numerous ESS.  These stations measure real-time atmospheric parameters, pavement conditions, water level conditions, and visibility.  Central RWIS hardware and software are used to process observations from ESS to develop nowcasts or forecasts, and display or disseminate road weather information in a format that can be easily interpreted by a manager.  RWIS data are used by road operators and maintainers to support decision making.  Real-time RWIS data is also used by Automated Warning Systems (AWS).  The spatial and temporal resolution can be that of a mesonet.  The data is often considered proprietary although it is often ingested into numerical weather prediction models.
Answer: Weather Underground