This paper is organized as follows. In Sect. 2, the case
study and the radar data used for the assimilation are described.
A brief explanation of the WRF–3DVAR system and
the radar data operator is presented in Sect. 3. The 3DVAR
experiments and the corresponding forecast results are discussed
in Sects. 4 and 5, respectively. The impact of outer
loops is analyzed in Sect. 6, whereas summary and conclusions
are given in Sect. 7.