Evaluation of the NAVGEM analyses and forecasts of tropical cyclones and comparison with GFS analyses and WRF high-resolution numerical simulations

Accurate prediction of hurricane track and intensity is a challenging problem in numerical weather prediction with global models due to uncertainties in the numerical models. Evaluation of the performance of a forecast model is an important step to guide the model improvements. In this study, a statistic evaluation of the track and intensity forecasts has been performed first for the Navy Global Environmental Model (NAVGEM)during June to November 2014 for Atlantic, East Pacific and West Pacific Basins. Results show that: 1) the averaged track errors of NEVGEM are ranging from 100 to 460 km and growing with forecast lead time for one- to five-day forecast; 2) the NAVGEM model has good skill in terms of forecasts of the intensity trend, although the predicted intensifications lag the observed times in many cases.

Then, two notable recent hurricanes, Joaquin and Patricia (2015) are being used to evaluate the ability of NEVGEM analyses and forecasts to represent the atmospheric conditions for both environment and vortex core regions of the hurricanes. Specifically, the NEVGEM analyses and forecasts are being compared with NCEP Global Forecast System (GFS) analyses, observations obtained from the recent field program (e.g., TCI-15) conducted by the Office of Naval Research (ONR), as well as a series of mesoscale high-resolution numerical simulations from an advanced research version of the Weather Research and Forecasting (WRF) model. Specifically, owing to the lack of understanding of the influence of tropical cyclone outflow layer on the numerical prediction of the tropical cyclone rapid intensification, specific attention will be giving to the comparison of atmospheric conditions in the outflow layer. Satellite data will be assimilated into the WRF model in order to obtain more accurate structure of the outflow layer. Results and major findings will be presented.