Metcast is a request-reply and subscription system for dissemination of real-time weather information. The system comprises clients and servers communicating via the HTTP protocol. A Metcast server maintains a database of weather observation reports, forecasts, advisories, gridded data produced by weather models, satellite imagery and plain text messages and discussions. A Metcast server -- an application (web) server -- delivers a subset of these data in response to a query formulated in a domain-specific declarative language.

One particular source of original data is World Meteorological Organization's (WMO) data feed, containing a great number of land and sea surface and depth/height profile reports, forecasts, advisories, discussions, etc. -- for the whole globe. A set of decoders processes the feed, and stores raw and decoded data in a database. A Metcast server distributes this information in an XML OMF format.

The Metcast server, the set of decoders for various WMO data formats, auxiliary and monitoring CGI scripts are all written in Scheme. Metcast clients are written in C++, Java, Scheme, Perl, Python, JavaScript, and Visual Basic.

Also see the Metcast home page.