National Blend of Models (NBM)

Overview

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.

Versions

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 region two times a day. Version 2, released November 15, 2016 in CONUS and OCONUS AWIPS 16.2.2, added coverage over Alaska, Hawaii, and Puerto Rico.

Further versions aim to expand on the current NBM capabilities. Version 3 makes major changes to the blend capabilities. Over CONUS, V3.0 will run hourly from 0-36 hours. The number of models used in the blend has also been greatly increased, and now includes numerous mesoscale and short-range models in addition to global models used in previous versions. In addition to temperature and winds, the version 3.0 will produce precipitation forecasts, Ceiling height and Visibility, as well as supporting weather, snow, and ice forecasts. Additionally V3.0 will add precipitation to Alaska and Hawaii.

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. [Login required]

Comparison of NDFD graphical product (top) and the National Blend of Models (NBM) product (bottom) for Winds

National Blend Comparative Viewer
** Requires login credentials **

The image shows the NBM has more detail and fewer unnatural contours than NDFD

Performance Examples

Hurricane Matthew, October 7, 2016 12z - Wind Gusts
(Blend 48hr forecast)

Upper left: NDFD, Upper right: Blend, Lower left: GMOS, Lower right: URMA (observations)

Sacramento, CA, January 11, 2017 00z - 06hrQPF
(Blend 36hr forecast)

Upper left: NDFD, Upper right: Blend, Lower left: WPC, Lower right: URMA (observations)

Front in southwest USA, December 17, 2016 00z - Temperature
(Blend 12hr forecast)

Upper left: NDFD, Upper right: Blend, Lower left: GMOS, Lower right: URMA (observations)

More detailed examples are available at the NWS Insider NBM Performance Page [NWS and affliates only; 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

Introduction to the NWS National Blend of Global Models, (2015), published by The COMET^® Program.
Gridded Products in the NWS National Blend of Global Models, (2016), published by The COMET^® Program.
Verification Methods in the NWS National Blend of Global Models", (2016), published by The COMET^® Program.
Statistical Methods in the NWS National Blend of Global Models, (2016), published by The COMET^® Program.

Reference Presentations

K. K. Gilbert, J. P. Craven, D. R. Novak, T. M. Hamill, J. Sieveking, D. P. Ruth, and S. J. Lord, 2015: An Introduction to the National Blend of global Models Project. Special Symposium on Model Postprocessing and Downscaling, Phoenix, AZ, Amer. Meteor. Soc., 3.1.
K. K. Gilbert and D. T. Myrick, 2015: An Introduction to the National Blend of Global Models Project, NOAA Virtual Laboratory Forum Presentation - February 18, 2015.
B. Veenhuis, 2015: Science Behind the National Blend of Models Temperature Elements. NOAA Virtual Laboratory Forum Presentation - April 15, 2015.
T. Hamill, 2015: The Science Behind Multi-model Precipitation in the National Blend of Models. NOAA Virtual Laboratory Forum Presentation - July 15, 2015.
K. K. Gilbert, D. T. Myrick, J. P. Craven, J. P. Gagan, T. M. Hamill, D. R. Novak, D. P. Ruth, J. Settelmaier, J. E. Sieveking, and B. Veenhuis Jr, 2016: The National Blend of Global Models, Version One. 23rd Conf. on Probability and Statistics in the Atmospheric Sciences, New Orleans, LA, Amer. Meteor. Soc., 1.3.
M. A. Tew, A. Stern, A. Horvitz, K. Gilbert, and D. T. Myrick, 2016: National Blend Of Models: Transformational Forecast Change by the National Weather Service , 4th Symp. on Building a Weather-Ready Nation, New Orleans, LA, Amer. Meteor. Soc., 6.2.
Huntemann, T., D. Ruth, and D. Plumb, 2017: Verification of the National Blend of Models, 28th Conference on Weather Analysis and Forecasting, Seattle, WA, Amer. Meteor. Soc.,7B.3
Hudson, M., M.A. Tew, L. Wilson, M. Dion, 2017: National Blend of Models: Early Results from a Field Demonstration, 5th Symposium on Building a Weather-Ready Nation: Enhancing Our Nation's Readiness, Responsiveness, and Resilience to High Impact Weather Events, Seattle, WA, Amer. Meteor. Soc., 4.1