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Home > NEMS NMMB documentation

The NOAA Environmental Modeling System (NEMS) is a common modeling framework whose purpose is to streamline components of operational modeling suites at NCEP. NEMS architecture is based on the Earth Modeling System Framework (ESMF). It is also part of the National Unified Operational Predication Capability (NUOPC) with Navy and the Air Force, and will eventually provide support to the community through the Developmental Test Center (DTC).

The first implementation of NEMS at NCEP is in the NAM modeling suite. The NAM prediction model in NEMS is the Nonhydrostatic Multiscale Model on B-grid (NMMB). The NMMB can be run either globally or regionally with embedded nests. In the NAM, the NMMB runs over the existing North American domain to 84-h, within which are four static one-way nests which run to 60-h: 4 km CONUS, 6 km Alaska, 3 km Hawaii, and 3 km Puerto Rico. Data from these nests will be available on NOMADS at a later date. Within either the CONUS or Alaska nest a placeable on-call nest at 1.333 km (CONUS) or 1.5 km (Alaska) is run to 36-h to provide support for fire weather and other hazardous situtations.

NOMADS contains NAM output over the following locations:

  • CONUS (awphys) on the 12-km Lambert-conic conformal grid (#218)
  • North America (awip32) on the 32-km polar-stereographic grid (#221)
  • Alaska (awak3d) on the 11.25-km polar-stereographic grid (#242)
  • Hawaii/Central Pacific (afwahi) on a 0.108 deg latitude/longitude grid (#182)
  • Caribbean/Central America (afwaca) on a 0.108 deg latitude/longitude grid (#181)
The domains covered by the NAM and these output grids can be viewed at

NCEP NEMS home page:
Implementation briefing:
NCEP Model Graphics:
NCEP NAM Home Page:


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