11B.3 NCEP Modeling Efforts to Assist with Nowcasting Challenges

Thursday, 11 January 2018: 9:00 AM
404 (Hilton) (Austin, Texas)
Geoffrey S. Manikin, NOAA/NWS/NCEP/EMC, College Park, MD; and J. R. Carley, J. Du, B. S. Ferrier, M. E. Pyle, E. Rogers, and V. Tallapragada

Numerical weather prediction has great potential to assist with the major challenge of nowcasting. These very short-range forecasts can be greatly improved through the use of frequently-updated high-resolution models, and the assimilation of radar data gives them greater opportunities to start with a more-correct initial picture of the atmosphere and avoid the spin-up issues that affect models without assimilation of radar data.

NCEP currently runs the NAM nest every 6 hours, the ARW and NMMB high-resolution windows (HiResW) every 12 hours, and the High-Resolution Rapid Refresh (HRRR) hourly. The NAM nest and Hi-Res Windows are run over CONUS, Alaska, Puerto Rico, and Hawaii, while the HRRR is run over CONUS and will soon be run (at 3-hour intervals) over Alaska. All have horizontal resolution at or close to 3 km. The NAM nest and HRRR use radar reflectivity data in their intialization, while the Hi-Res Windows do not directly assimilate radar data, but the CONUS and Puerto Rico versions get their initial conditions from a model (RAP) that does.

Of course, with multiple high-resolution models that are frequently updated, there is a lot of data for a forecaster to process, and generating simplified output can greatly assist the forecasting process. NCEP will soon be implementing the Version 2 of the High-Resolution Ensemble Forecasting system (HREF) which generates mean and probability fields from several of the high-resolution forecasting systems, effectively matching the output from the popular Storm-Scale Ensemble of Opportunity (SSEO) generated by the Storm Prediction Center.

Going forward, NCEP plans to consolidate its modeling suite and potentially add frequently-updated high-resolution ensembles. Version 2 of the HREF will serve as a benchmark for future high-resolution ensemble systems to beat. Future NCEP modeling plans in support of nowcasting capabilities will round out the presentation.

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