Operational Implementation of High-Resolution Triple-Nested HWRF at NCEP/EMC - A Major Step Towards Addressing Intensity Forecast Problem

The NCEP operational Hurricane Weather Research and Forecast (HWRF) modeling system is being upgraded with triple-nest capability that includes a cloud-resolving inner most grid operating at 3 km horizontal resolution. This high resolution ocean coupled HWRF system is jointly developed by the HWRF team at NCEP/EMC and the hurricane modeling team at AOML/HRD, and is tested in real-time for the 2011 hurricane season through participation in and support from NOAA's Hurricane Forecast Improvement Project (HFIP). This is a major step towards improving the intensity forecast skill and address rapid intensity changes.

This presentation will provide an overview of advancements to the HWRF-POM coupled modeling system, with special emphasis on changes to model configuration and physics suitable for higher resolution. These include implementation of a new centroid based vortex tracking algorithm, re-design of the operational HWRF initialization procedure with improved interpolation algorithms, implementation of new GFS PBL and Shallow Convection parameterization schemes, modifications to Ferrier Microphysics scheme and further advancements to air-sea physics and ocean coupling.

Details of computational efficiency experiments will be discussed along with a detailed pre-implementation strategy adopted for 2012 hurricane season. Preliminary results indicate significant improvements in track and intensity forecast skill compared to current operational HWRF. Better representation of hurricane structure is expected as a result of the higher resolution, advanced physics and improved vortex initialization procedures. High-resolution model diagnostics will be presented with a focus on comparisons to available aircraft and remotely sensed observations.