Performance of the 2017 Real-Time HWRF-Based Ensemble and Combined HWRF/HMON/COAMPS-TC Multimodel Ensemble

The NOAA/NCEP/EMC operational HWRF based Ensemble Prediction System (HWRF-EPS) has undergone constant improvements, and has been running real time parallel for storms in the North Atlantic basin for the last four years. The upgrades of HWRF-EPS included situation-appropriate perturbations to the initial-time position and intensity and stochastic perturbations for convection, PBL, and surface layer physics schemes.

In this study, the FY17 HWRF-EPS upgrades are reviewed and the ensemble performance is verified against best track data for 2017 North Atlantic hurricane season in terms of both track and intensity forecasts. The HWRF-EPS results are compared with its deterministic version and other top-flight regional models. The evaluation also includes demonstration of the improvement of statistical features of the current HWRF-EPS, such as track and intensity spread, over the previous version.

The HWRF-EPS is further extended to a joint multi-regional model EPS by combining HWRF, HMON, COAMPS-TC ensembles. The probabilistic forecasts of the joint ensemble system are verified and evaluated, and compared to their deterministic versions. New probabilistic forecast products are developed based on the joint ensemble system. The statistical features are investigated and analyzed to ensure the effectiveness and robustness of the system.

Key words: HWRF, Multi-model, Ensemble, Hurricane Track/Intensity