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The Real-Time Mesoscale Analysis (RTMA) is a NOAA/NCEP high-spatial and temporal resolution analysis/assimilation system for near-surface weather conditions. Its main component is the NCEP/EMC Gridpoint Statistical Interpolation (GSI) system applied in two-dimensional variational mode to assimilate conventional and satellite-derived observations.
The RTMA/URMA was developed to support NDFD operations and provide field forecasters with high quality analyses for nowcasting, situational awareness, and forecast verification. The system produces hourly analyses at 2.5 km resolution for the Conus NDFD grid and the Northwest River Forecast Center (NWRFC) grid, 3km analyses for the Alaska NDFD grid and 2.5 km analyses for the Hawaii and Puerto-Rico NDFD grids. Three-hourly analyses at 2.5km are also produced for the Guam NDFD grid.
The so-called Un-Restricted Mesoscale Analysis (URMA) is similar to the RTMA, except it runs six-hours later in order to incorporate observations that arrive too late for the RTMA. URMA is therefore a more accurate analysis to use for for verification. Hourly URMA analyses at 2.5 km resolution are currently available for the Conus NDFD grid and the NWRFC grid.
Plans for the future include creating URMA analyses for Alaska, Hawaii, Puerto, and Guam.
RTMA fields for regions of the CONUS are displayed on the NCEP Model Analyses & Guidance page.
In addition, NCEP/EMC displays its near-real-time parallels for evaluation e.g. 2.5 km CONUS and 2.5 km Guam.