Validation of The Regional Wave Prediction System (RWPS) Forced by Forecaster-Developed Gridded Hurricane Wind Fields

The National Weather Service's National Centers for Environmental Prediction (NCEP) currently produces numerical wave model guidance products ranging from a global domain, at different resolutions from 30 arc-min to 1 arc-min (WW3 Multi-grid Global wave prediction system – WW3_Multi) to small, local Weather Forecast Office (WFO) domains along the US coast (Nearshore Wave Prediction System – NWPS). However, forecasters at the National Hurricane Center (NHC), Ocean Prediction Center (OPC) and the Central Pacific Hurricane Center (CPHC) require wave guidance driven by their official wind forecast in order to produce consistent text, gridded and graphical products and services for the marine community. Moreover, the wave guidance provided by NWPS is generated by forcing this system with human forecaster-enhanced wind grids from the WFOs, and at the boundaries with wave spectra from WW3_Multi, which in turn is forced by Global Forecast System (GFS) winds. During tropical cyclone events, the NWPS must be forced with the winds from the official (OFCL/TCM) forecast provided by NHC while still forced at its boundaries with spectra from WW3_Multi. It is not uncommon to see discrepancies due to the information that drives NWPS and the forcing at its boundaries when the hurricane track and intensity differ between the GFS and the forecaster-enhanced wind fields. To address those issues, the Regional Wave Prediction System (RWPS) is currently being developed to provide high-resolution (5.5 min) wave model guidance to NHC’s forecasters, and eventually to their counterparts at OPC and CPHC in their areas of responsibility. The RWPS is driven by forecaster-enhanced wind grids from NHC and boundary conditions from WW3_Multi. It includes surface currents from the global Real-time Ocean Forecasting System (RTOFS) and it runs centrally on the NCEP supercomputers. The RWPS will produce boundary conditions for coastal offices NWPS that can be used during a storm event along with the official wind fields derived from by NHC’s forecast. RWPS development efforts have recently been focused on optimization of wave model settings, wave partitioning and spatial and temporal wave tracking. The architecture of the numerical system is discussed and examples of its operational products are shown. Validation, of RWPS output, is carried out using buoy and satellite measurements in both the Pacific and Atlantic domains. RWPS output is also compared against WW3_Multi output.