Surface Winds in 2008 Hurricane Ike: Observations and High-Resolution Model Forecasts

Accurate surface wind observations are a key in determining the intensity of a hurricane. Since forecasts of intensity and structure have been improved lately, it is important to have accurate observation to evaluate this improvement. First, this study compares the observation H-Wind Analysis from NOAA airborne data with NDBC moored buoys and selected surface observations (ships) over the Gulf of Mexico from September 8-13, 2008 during the Hurricane Ike. Ike caused extensive damage across parts of the northwestern Gulf Coast when it made landfall along the upper Texas coast at the upper end of Category 2 intensity.

Furthermore, surface observations are compared with high-resolution cloud-resolving models like MM5 and WRF, also with ocean coupled models like UMCM and CWRF. Results indicate that H-Wind may have overestimated the wind speed in the inner core and underestimated in the outer regions in Hurricane Ike. The uncoupled atmospheric models, MM5 and WRF, overpredict surface winds compared to the observations, largely due to the lack of coupling to the ocean. But, with the track error of each model, precise evaluations are difficult to make. The results presented in this study suggest that more analysis of both the observations and model forecasts are needed to further examine the full range of surface wind speeds, not just the maximum winds in hurricanes. As well it is essential to estimate the uncertainty of observations and model forecast.