National Digital Forecast Database

National Digital Forecast Database (NDFD) Extensible Markup Language (XML) is a service providing the public, government agencies, and commercial enterprises with data from the National Weather Service�s (NWS) digital forecast database. This service, which is defined in a Service Description Document, provides NWS customers and partners the ability to request NDFD data over the internet and receive the information back in an XML format. The request/response process is made possible by the NDFD XML Simple Object Access Protocol (SOAP) server.
More information: http://www.weather.gov/xml/