The National Weather Service National Blend of Models (NBM) was updated to version 3.0 on 27 July 2017. Changes include:
Eight new components for the contiguous U.S. (CONUS) and Alaska, including four deterministic models, two ensemble systems, and two post-processed statistical components
Five new components for Hawaii and Puerto Rico
Expanded forecast domains for the CONUS and Alaska
A “Time of Day” (ToD), rather than NWP model, initial time concept
Hourly NBM forecasts, with short, day 2-4, and extended forecasts
Updated NBM guidance available 50-60 minutes after hourly run time
New weather elements for aviation and winter weather forecasting including precipitation type; and new QPF, cloud bases, ceilings, and visibilities
New computation methods for wind direction and doubling of model components for ocean winds
NBM v3.0 products have different characteristics from the previous v2.0. Coupled with the new “ToD” paradigm and new weather elements, the new NBM v3.0 results in big changes to forecast operations.
This lesson starts with a five-minute video that describes these changes. Then to illustrate how forecast operations will be affected, we follow forecasters through important parts of a day shift, using NBM products to predict a winter storm.
Upon completion of this lesson, the learner should be able to do the following:
Identify at least three new mesoscale model components of the NBM Version 3.0.
Identify at least five new products in NBM Version 3.0.
Describe the operational impact of the “Time of Day” NBM paradigm.
Demonstrate correct use of blend products that support the preparation of
winter weather forecasts,
ceilings and visibilities in Terminal Aerodrome Forecasts (TAFs), and
marine forecasts.
National Blend of Models, NBM, mesoscale, time of day, model domain, aviation, TAF, winter weather, wind direction, precipitation type, NBM v3, National Weather Service, NWS
Program Oversight
Amy Stevermer - UCAR/COMET
Project Lead/Scientist
William Bua - UCAR/COMET
Instructional Design
Alan Bol - UCAR/COMET
Graphics/Animations
Steve Deyo - UCAR/COMET
Lindsay Johnson - UCAR/COMET
Audio/Video Editing/Production
Steve Deyo - UCAR/COMET
Audio Narration
Sylvia Quesada - UCAR/COMET
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