Overview of Running a Regional Basin Scale Nature Run for Hurricane OSSEs

In this work, we present our methodology for running a high resolution, basin scale nature run using the Non-hydrostatic Multiscale Model on the B grid (NMM-B). NASA's global, 7 km GEOS-5 Nature Run (G5NR) is used for initial and boundary conditions. We use a horizontal resolution of 3 km for the initial  basin scale forecast. To allow for more high resolution simulation of observations, 1- and 2-km resolution nature runs will also be generated with different domain sizes.
We begin with an overview of our methodology, including software development and interaction of componenets. The configuration of the model and pre-processor are also described. We then evaluate the resulting forecast by analyzing various fields from one of many tropical storms that occur throughout the G5NR. We also show how this nature run fits into our HWRF-based hurricane OSSE system. Since a single, large, high-resolution grid is used, this nature run addresses a problem we had in our previous regional nature run, which relied on nesting and hence had a relatively small area with data at high resolution. Another advantage of using the G5NR is that it allows us to investigate multiple cases. By using the basin scale domain with NMM-B, situations in which multiple storms occur at once can also be used.