We evaluate experiments from 15 August – 30 September and the first two weeks are used for the spin-up period. For each experiment, 168-hr GFS forecasts are generated once per day at 00Z, with a total of 47 forecasts. To test the impact of RO, we conduct two experiments: 1. A control experiment assimilating simulated surface pressure, temperature, specific humidity, u- and v-wind, and satellite radiance; and 2. An RO experiment adding simulated RO observations to the control configuration.
We use tropical cyclone best tracks derived from G5NR to evaluate how the proposed RO constellation impacted the forecasts. Both basin-scale and case study approaches are used. Track and intensity errors are calculated for each forecast and tropical cyclone in the Atlantic, East Pacific, and West Pacific basins. Basin-averaged statistics are presented. Forecasts for two landfalling hurricanes in the Gulf of Mexico are investigated further with an emphasis on the associated convective environment conducive for tornadoes. Preliminary results suggest improvements in track forecasts and mixed results for intensity forecasts during one of the landfalling tropical cyclones.