NCEP Announces the Implementation of the Weather Research and Forecast (WRF) Model for Operational Forecasting

The long-awaited operational implementation of the WRF modeling system became a reality at the National Centers for Environmental Prediction (NCEP) at 1200 UTC on September 21, 2004. On September 16th, the WRF implementation plan was briefed to NWS Director D.L. Johnson, who approved this step following endorsement of the plan by the NWS Corporate Board. WRF represents an inter-organizational partnership to create the next-generation mesoscale numerical weather prediction (NWP) modeling system for research and operations that will facilitate operational NWP collaboration and accelerate the transfer of new science from research into operations. The implementation consists of both the Non-hydrostatic Mesoscale Model (NMM) WRF core run with NCEP-supplied physics, and the Advanced Research (AR) WRF core (formerly known as the Eulerian Mass core) run with National Center for Atmospheric Research (NCAR)-supplied physics. Both versions of WRF receive initial conditions and lateral boundary conditions interpolated from the 12-km operational Eta model using the WRF Standard Initialization software developed by NOAA.s Forecast Systems Laboratory. The WRF is replacing the current High Resolution Window (HRW) run, which has been providing 8 km Eta model guidance over four windows covering the Eastern U.S., Western U.S., Central U.S., and Alaska. Guidance will be provided from two WRF runs for each of these regions once per day. One run will be the NCEP 8 km Non-Hydrostatic Meso-scale Model and the other will be the NCAR 10 km Eulerian Mass Model. NCEP's new WRF-based modeling system represents the first U.S. operational implementation of WRF and is the first step on the way to an implementation of a WRF-based NCEP HRW mesoscale ensemble, which is scheduled for implementation next spring. The WRF program is managed through the NWS Office of Science and Technology.