The Rapid Refresh system (RAP) is an hourly-updated assimilation/modeling system running at 13 km resolution, developed at NOAA's Earth Systems Research Laboratory (ESRL). The RAP covers North America and is comprised of a numerical forecast with the Advanced Research WRF (WRF-ARW) model and an data assimilation system using the NCEP Gridpoint Statistical Interpolation (GSI) analysis. The RAP is complemented by the higher-resolution 3km High-Resolution Rapid Refresh (HRRR) model, which is also updated hourly and covering a smaller geographic domain. More information and hourly graphics from the RAP can be viewed at ESRL's RAP home page; HRRR information and graphics can be obtained at ESRL's HRRR home page.
RAP History at NCEP:
- RAPv1 - implemented 1 May 2012 at NCEP (replacing the Rapid Update Cycle - RUC )
- RAPv2 - implemented 25 Feb 2014 at NCEP
- RAPv3 - implemented 23 Aug 2016 at NCEP ; NWS Technical Information Notice on RAPv3/HRRRv2
- RAPv4 : Implemented on 12 July 2018
- RAPv5 - Planned implementation Summer 2020
A description of versions 1-3 of the RAP can be found in Benjamin et al. 2016, A North American Hourly Assimilation and Model Forecast Cycle: The Rapid Refresh. Mon. Wea. Rev., 144, 1669-1694.
Official RAP and HRRR graphics from the operational runs can be found at the NCEP Model Analysis and Guidance (MAG) web site.