Overview of National Blend of Models version 3.0 Part 2:  Bulk verification and high impact examples
Jeffrey Craven, NOAA/NWS/OSTI/MDL/SMB, Silver Spring, MD
Tabitha Huntemann, NOAA/NWS/OSTI/MDL/DFSB
Daniel Plumb, AceInfo Solutions, Inc.
David Rudack, NOAA/NWS/OSTI/MDL/SMB
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Abstract
The National Blend of Models (NBM) version 2.0  (NBM V2.0) was placed into operations in November 2016 at the National Centers for Environmental Prediction (NCEP).  This gridded guidance has five domains including the CONUS, Alaska, Hawaii, Puerto Rico, and a large Oceanic Domain that covers much of the Pacific and Atlantic Oceans.  The NBM V2.0 currently runs twice per day on the Weather and Climate Operational Supercomputing System (WCOSS), harnessing the 0000 UTC and 1200 UTC model cycle runs for 5 model systems. 

In the summer of 2017, NBM V3.0 is expected to become operational at NCEP.  There are a number of significant enhancements and capabilities that will be described in the presentation.  The NBM (with exception of Oceanic Domain) will be issued hourly using a Time of Day (TOD) nomenclature rather than traditional model cycle notation, essentially running each hour with the latest available suite of deterministic, ensemble, and statistically post-processed guidance.  The number of model inputs will roughly triple to 12-15 for the four CONUS and OCONUS sectors, and the number of ensemble members for Oceanic winds will double to over 40 inputs.

Part 1 describes the capabilities and upgrades of NBM V3.0.  This Part 2 is designed to provide bulk verification statistics on a variety of elements so far in 2017.  Several high-impact weather examples are presented to show the utility of the NBM during heavy precipitation events, strong wind events, and severe weather.

Although providing the greatest possible lead time on high impact events is critical, this presentation is intended to show that providing precision on the timing of weather events down to about an hour is obtainable.  Some decisions makers require this level of precision.  The provision of hourly time steps through 36 hours was designed to provide more information to assist forecasters in Enhanced Short Term Forecasts in the first 1-2 days.