VDRAS and polarimetric radar investigation of a bow echo formation after a squall line merged with a preline convective cell

This paper is the first to document the development of a type of bow echo, termed merger-formation bow echo (MFBE), in southeast China evolving from a subtropical squall line (SL) merging with a preline convective cell (CC). Although this MFBE did not produce damaging surface winds, its intense rain rate resulted in local flooding. The evolution of the kinematic, thermodynamic, and microphysical structures is investigated using the variational Doppler radar analysis system (VDRAS) analysis and polarimetric radar observations. Key factors of this MFBE event including the rear-inflow jet (RIJ) and cold pool exhibited different characteristics from those in classical bow echoes and limited MFBE cases.