Hourly-updated NWP forecasts are now running experimentally over North America (including Alaska) in the Rapid Refresh (RR) model/assimilation system, assimilating all available observations on an hourly basis using a 13km version of the WRF model. NOAA/ERSL/GSD is developing the RR, which will be transferred to NCEP to replace the current Rapid Update Cycle (covering a smaller domain not including Alaska) in 2010.
This talk will focus on the assimilation, modeling, and cycling design in the RR. The RR now running at NOAA/ESRL includes use of a digital filter initialization associated with radar reflectivity and lightning assimilation, and updated versions of the Grell-Devenyi convective scheme and RUC-Smirnova land-surface scheme, all in WRFv3. The WRF configuration for the RR will be described. The RR uses a modified version of NCEPâs GSI assimilation, including the cloud/hydrometeor assimilation following a design from the RUC for stable clouds.
If time permits, some information will also be presented on the Flow-following Finite-Volume Icosahedral Model (FIM) global model. The use of an isentropic-sigma hybrid vertical coordinate and a polygon-grid-based icosahedral horizontal grid (providing near-equal spacing globally including polar regions) are unique aspects of the FIM model. NOAA/ESRL is now running 7-10-day real-time forecasts at 30-15km scale using GFS initial conditions with promising results.