Real-Time Forecasts and Observing System Experiments in the CASA Dallas-Ft Worth Testbed

The Center for Collaborative and Adaptive Sensing of the Atmosphere (CASA) and its academic, National Weather Service, local government and private sector partners have established a testbed in the Dallas-Ft Worth area where a number of novel observing systems are in place and can be tested in numerical models in real-time and through the use of Observing System Experiments (OSEs). These instruments include radar data such as the NEXRAD WSR-88D radar network, two FAA TDWR radars and seven CASA X-band radars operating in an overlapping network. Also included are surface data such as the standard federal surface observing stations (ASOS, AWOS), NWS co-operative observing sites, automated surface stations from Earth Networks and Understory Weather, as well as several other public and private networks that are included in the Mesonet files of the NCEP Meteorological Assimilation Data Ingest System (MADIS), partially supported by the National Mesonet program. There have also been vertical profiling instruments provided by the private sector, including two microwave radiometer and three acoustic profilers (SODARs) deployed in the DFW Testbed region.

The Center for Analysis and Prediction of Storms operates a real-time analysis and short-term forecast system as part of the CASA DFW Testbed operations. Analyses at 400m horizontal resolution covering the lowest 10 km of the atmosphere are generated every 5 minutes from the radar and other data. Also, when there is precipitation in the area, ongoing or expected, 2-hour forecasts at 1-km resolution are generated every 30 minutes. Employing a 3DVAR analysis and efficient cycled Incremental Analysis Updating with Variable-Dependent Timing (IAU-VDT) data assimilation these 2-hour forecasts are generated in about 20 minutes using 200 processor cores. The analyses are used in CASA Testbed operations and the forecasts serve as a baseline reference system for OSEs to examine the impact of the various observing systems on the forecasts.

This work itemizes the available instruments, shows some forecasts of recent events and summarizes recent OSE results.