5.2    The User of WRF-DART Analyses for 3 km Explicit Convective Forecasts in Support of the 2012 DC3 Field Program

Romine, Glen, Morris Weisman, Kevin Manning, Wei Wang, and Craig Schwartz, Chris Snyder, and Jeff Anderson, National Center for Atmospheric Research

Realtime explicit convective forecasts at 3 km grid resolution were run from 01 May through 30 June to test the latest improvements in forecast capability with the WRF-ARW modeling system and to support the Deep Convective Clouds and Chemistry (DC3) field campaign. Forecasts to 48 h were produced twice a day, initialized at 00 UTC and 12 UTC. Again this year, WRF-DART was used to produce a 15 km horizontal resolution analysis, chosen from a 50 member ensemble, to initialize the 3 km explicit convective forecast. Based on the identification of significant biases from the similar use of WRF-DART during the 2011 Spring forecast season, WRF was reconfigured for both the continuously cycled analysis and forecast model this year to use the Tiedtke convective parameterization scheme on the 15 km grids, along with the Morrison microphysics scheme and RRTMG radiation scheme on both the 15 km and 3 km grid. The WRF-DART configuration and observation processing were also modified collectively with the model physics changes to reduce analysis bias. Preliminary results suggest a significant improvement in explicit convective forecast guidance over last yearŐs exercise. The presentation will highlight both specific case performance as well as summary statistics from the 3 km forecasts.