This talk will describe the methodology of Doppler radar data assimilation scheme designed for the WRF (Weather Research and Forecasting model) variational data assimilation system (WRF-Var). In addition, the current status in research and applications of the WRF-Var radar data assimilation are summarized. Several case studies and the real time applications show that the WRF-Var Doppler radar data assimilation can significantly improve the forecasting skills of mesoscale and microscale systems. Its multiple radar data assimilation capability is demonstrated by our recent study on the dry-line during the IHOP_2002 experiment, with OSSE and real data assimilations. Since US has a well distributed Doppler radar stations, the WRF-Var Doppler radar data assimilation system has great potential in research and real time applications. The recent implementation of the WRF-Var radar data assimilation is in the Mississippi Delta (Seperate talk by Pat Fitzpatrick).

Several additions or updates are planed in the WRF-Var radar data assimilation scheme, including improvement of the observation operator to include ice hydrometeors, more sophisticated microphysics and diabetic initialization of the analysis for WRF. We will also discuss the future plan in real-time applications and further development with WRF 4D-Var.