ESRL Global Systems Division
MSAS in AWIPS Build 5.2.2
Analyses, or gridded fields, of current surface observations are essential to successful weather prediction because they provide direct measurement of surface conditions, allow inference of conditions aloft, and provide crucial indicators of severe weather. Surface analyses provide forecasters with detailed information on the development and movement of surface weather systems, and are particularly valuable at small spatial and temporal scales where the frequency, completeness, and density of surface data are unmatched among in situ observations.
To provide National Weather Service (NWS) forecasters with timely and detailed surface analyses, FSL developed the Mesocale Analysis and Prediction System (MAPS) Surface Assimilation System (MSAS) for implementation on the Advanced Weather Interactive Processing System (AWIPS) installed at each NWS Forecast Office. MSAS exploits the resolution of surface data by ingesting, quality controlling, and analyzing surface observations from all available AWIPS sources, including local mesonets acquired through the AWIPS LDAD system. On AWIPS, MSAS produces hourly, gridded fields for 16 surface variables, and also provides QC information for the AWIPS Quality Control and Monitoring System.
Although the domain and resolution parameters for MSAS are flexible, on AWIPS they have always been preset to cover the Continental United States (CONUS) with a 60-km analysis grid. Starting in AWIPS Build 5.2.2, however, each forecast office will be able to modify the location, size, and resolution of its local MSAS domain, and will also be able to specify the model background utilized in the MSAS analyses, the level of the MSAS pressure reduction (e.g. 1500m or sea level), and the time interval used in the MSAS pressure change analysis (e.g. 1-h or 3-h pressure change). Changes in the domain size will be linked to changes in the grid resolution in such a way as to minimize AWIPS impacts and guarantee that overall MSAS computational demands remain the same. For example, forecast offices can choose a 15-km, regional-scale domain, or a 60-km CONUS domain, but not a 15-km CONUS domain. Starting in Build 5.2.2, MSAS will also, for the first time, support domains outside the Continental U.S., e.g. Alaska and Puerto Rico.
More information is available in the MSAS localization guide.
Name: Patty Miller