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.