Development and Evaluation of a Three-Dimensional Rapidly Updating Real-Time Mesoscale Analysis (RTMA)

The Real-Time Mesoscale Analysis – Rapid Update (RTMA-RU) is an NCEP operational analysis product that provides detailed analyses of surface and sensible weather elements every 15-min (rapid-update). These analyses are heavily used by National Weather Service (NWS) forecasters in a variety of ways (situational awareness, bias correction for the National Blend of Models, verification). The current RTMA-RU is based on a 2D application of a specialized form of the Gridpoint Statistical Analyses (GSI) and aspects of it are described in other presentations at this WAF/NWP conference.

In this presentation, ongoing collaborative work (between NCEP/EMC and ESRL/GDSD) to evolve the current 2D RTMA-RU to a fully three three-dimension analysis (3D RTMA-RU) will be described. In this new 3D RTMA-RU, 2D fields that are intrinsically a function of 3D space (PBL height, precipitable water, ceiling, etc.) are diagnosed from the 3-D RU-RTMA fields, yielding full physical consistency through use of a very accurate high-resolution model background. Extending the operational RTMA-RU to three dimensions will also allow for the creation of nowcasting products, including full-column representation of standard meteorological fields such as temperature, water vapor, and wind, as well as hydrometeors (i.e., clouds, precipitation of all forms), and eventually aerosols. The 3D RTMA-RU will also include land-surface diagnostics (e.g., soil moisture, snow state from multi-level land-surface fields), and convective (e.g., hail size, supercell rotation tracks) fields, developed in collaboration with the National Water Center (NWC) and National Severe Storms Laboratory (NSSL), respectively. The 3D RTMA-RU will potentially improve analysis fields for the NOAA National Blend of Models (NBM) project and add a 3-dimensional perspective including cloud-hydrometeor fields. It could also allow merging in of the NCEP/SPC Hourly Mesoscale Analysis and also provide an initial set of fields for a unified NOAA nowcast system.