Evaluation of Preliminary Cases of 3D-RTMA/URMA as a Preparatory Step toward Developing Requirements

he primary mission of the Analysis and Forecast Branch (a.k.a. AFS11) in the Analyze, Forecast, and Support Office of National Weather Service (NWS) is to address the field’s needs on Analysis and Forecasting by developing operational requirements for modeling systems used by the NWS forecasters, including regional analysis systems such as the RTMA/URMA (Real Time Mesoscale Analysis / UnRestricted Mesoscale Analysis. RTMA/URMA is the official mesoscale analysis system for NWS forecasters, which provides the forecasters with the Analysis of Record of the current atmospheric state. The URMA, which is identical to the RTMA except that it takes in 6-hr later data, is used as verification data source of NWS’ post-processing systems, the NBM (National Blend of Models), and thus ensuring its quality is important for NWS’ weather forecasting and warning.

We previously developed requirements for the 2D version of the RTMA/URMA in two sets. The first set was for general requirements proposing systematic and fundamental enhancements of the system by improving representation of spatiotemporally-varying effects of significant terrain variation (over mountains, coastlines, lakes, and islands) using physics-based methods for observation data quality control, modeling, downscaling, and/or data assimilation. The second set focused on improving the processes or algorithms for Quality Control (QC) and Station Flagging, and the utilization of sensor information, station types and additional data sources from various data collecting networks. It also presented a set of threshold tolerances of the key model parameters such as the temperature, dew point temperature, wind, quantified precipitation, and wave height.

Our goal is to adjust and expand our requirements for 2D-RTMA/URMA to the 3D version, which is currently available as a preliminary version. We are collecting feedback on the 3D RTMA/URMA in order to identify issues, needs, and other concerns so that requirements can be developed to help address them in future versions. In particular, we are collecting field cases we can look into and utilize to refine our existing requirements or even develop new requirements. For this purpose, we developed a web-based data viewer that compares model results over the Contiguous USA with corresponding verification, e.g., the MRMS (Multi-Radar Multi-Sensor System) and SPC (Storm Prediction Center) Mesoanalysis. It can also compare model data with sounding data.

This presentation will provide an outline and some details of our evaluation effort for refining our requirements for the RTMA/URMA.