Using geographic information systems to develop gridded model output statistics

The Meteorological Development Laboratory (MDL) of NOAA's National Weather Service (NWS) is developing a National Digital Guidance Database (NDGD) at a resolution of 5 km or higher to complement the existing National Digital Forecast Database (NDFD). To help accomplish this goal, MDL is creating a gridded Model Output Statistics (MOS) forecast guidance system. Current MOS forecast guidance is produced for the United States and its territories at approximately 1700 hourly reporting sites and over 5000 cooperative observation sites.

The initial development of gridded MOS is focused on the western third of the contiguous United States. Traditional observing stations used to develop MOS for this region are sparsely located, leaving developers searching for additional observational data sets as well as better predictor variables to capture terrain effects. Efforts were made to gather, quality-control, and archive data from additional meteorological observing systems, but even the use of these data did not bring the observed data resolution to the desired NDFD resolution of 5 km. To supplement the meteorological data and tailor the MOS forecast guidance to terrain, we used a Geographic Information System (GIS) to generate additional geophysical variables at the proper NDFD grid resolution. For this purpose, grids of elevation, slope, aspect, land cover, and a land/water mask were created. Additionally, the GIS was employed to generate the map specifications for the western third of the United States as well as a station dictionary including land/water designations for the observing stations.

In this talk, we discuss the GIS efforts used so far in the development of the gridded MOS guidance. We discuss some of the details of the GIS processes for developing the geophysical variables, including information about the parent data sets. Plans for the use of GIS to generate additional climatological and geophysical data sets for future gridded MOS development will also be presented.