About the National Blend of Models (NBM)

The National Blend of Models (NBM) is a nationally consistent and skillful suite of calibrated forecast guidance based on a blend of both NWS and non-NWS numerical weather prediction model data and post-processed model guidance. The goal of the NBM is to create a highly accurate, skillful and consistent starting point for the gridded forecast. This new way to produce NDFD grids will be helpful providing forecasters with a suite of information to use for their forecasts. The NBM is considered an important part of the efforts to evolve NWS capabilities to achieve a Weather-Ready Nation.


V1.0 - V2.0

The first version of the NBM was released January 6, 2016 in CONUS AWIPS 16.1.1, after Congress mandated that the NWS develop a blended model approach following Hurricane Sandy in 2012. This first version used 3 models (GFS, GEFS mean, CMCE mean) and covered temperature, wind, and sky cover over the CONUS (Continental United States) region two times a day. Version 2, released November 15, 2016 in CONUS and OCONUS (outside-CONUS) AWIPS 16.2.2, added coverage over Alaska, Hawaii, and Puerto Rico.


Version 3.0, released July 27th, 2017 (AWIPS 17.3.1) incorporated additional global and mesoscale models for the CONUS, OCONUS, and Oceanic domains along with running hourly and providing 1-36h forecasts. Several new weather elements were added to this version such as calibrated Probability of Precipitation (6-hour) and QPF, ceiling height and visibility, and weather, snow, and ice forecasts to name a few. An exhaustive lists of weather elements added to V3.0 can be found in NWS SCN 17-59.


NBM V3.1, which is planned to be implemented October 3, 2018 (AWIPS 18.1.1) will continue to incorporate additional global models (i.e.., ECMWF (deterministic and ensemble)) and mesoscale models (i.e., HRRR-Extended (1-36h guidance)) into its suite of model guidance to cover the CONUS, OCONUS, and Oceanic domains. This upgrade will enable the NBM to fill existing product gaps requested by the Aviation, Fire Weather, Water Resources, and Marine NWS Service Program Offices. To date, NBM data has been packaged in GRIB2 and only provided forecasts at gridpoints. NBM V3.1 will introduce a new text product (similar to MOS-station bulletins) that will provide NBM forecasts at stations. The data in these bulletins are the NBM’s nearest grid point forecast to the corresponding station. We will be generating four individual NBM text bulletin products every hour, each covering different forecast horizons. For a complete discussion concerning these messages along with an exhaustive listing weather elements that will be added to NBM V3.1 and their dissemination times please see the following NBM V3.1 SCN.

For NWS employees and affiliates, more information on versions and development can be found at the NWS Insider NBM Page, and the NBM VLab Page. [NOAA Login required]

Training and Additional Information Resources

For more information on the National Blend of Models, please see the following training resources and publications. 

Training Modules

Reference Publications

Reference Presentations