The Meteorological Development Laboratory (MDL) of NOAA's National Weather Service (NWS) is generating a gridded Model Output Statistics (MOS) forecast guidance system in support of for the National Digital Forecast Database. Currently, gridded MOS populates a 5-km grid with elements needed for weather forecast grids covering the contiguous United States (CONUS).

Stations used in traditional MOS development are unevenly distributed, leaving developers searching for additional observational data sets as well as better predictor variables to capture terrain effects. Despite efforts to increase the resolution of the meteorological observation data set, the network of quality-controlled observed data is shy of the desired NDFD resolution. To supplement the meteorological data and tailor the MOS forecast guidance to terrain and coast lines, we used a Geographic Information System (GIS) to generate additional geophysical variables at the agreed upon NDFD grid resolution. As forecasters have begun to use gridded MOS, GIS has been used to compare forecast and guidance grids, to edit the aforementioned geophysical predictor variables, and to identify and remove misrepresentative stations to better represent the guidance area. GIS was utilized to manipulate final product coverage areas along the US borders for the CONUS as well as to generate development areas for Alaska.

In this talk, we discuss the use of GIS in the development and evaluation of gridded MOS. We discuss some of the details of the GIS processes used to generate and assess geophysical components of gridded MOS, to create a station dictionary including land/water designations for the observing stations, and analyze or troubleshoot problem areas in gridded MOS weather elements. Plans for the use of GIS to aid in future gridded MOS work will also be presented.