Five synoptic scale medium-range models in general use

NWS's Global Forecast System (GFS), which runs out to 16 days,  originally known as two separate models (the aviation model, or AVN, and the medium-range forecast, or MRF) launched in 2000, replacing the Nested Grid Model and Global Spectral Model. The AVN and MRF merged into each other in 2002 and took on the current name. Because of relatively poor results compared to other global models around the world, since 2007 the U.S. government has been developing a replacement, the Flow-following, finite-volume Icosahedral Model (FIM), which is slated for a 2014 operational launch.

ECMWF's Integrated Forecast System (IFS), which run out 10 days

CMC's Global Environmental Multiscale Model (GEM), which run out 10 days

UK Met Office's Unified Model, which runs out to 6 days

Navy Global Environmental Model (NAVGEM) is a global numerical weather prediction computer simulation run by the United States Navy's Fleet Numerical Meteorology and Oceanography Center 180 hours  NAVGEM became operational in February 2013, replacing the NOGAPS.