Rapid Volumetric Growth of Misocyclone and Vault-Like Structure in Horizontal Shear Observed by Phased Array Weather Radar

The present paper reports a sub-minute scale growth of a misocyclone and vault-like structure in a horizontal shear environment observed by a phased array weather radar (PAWR). Between 0756 and 0801 Japan Standard Time on 25 August 2013, dual radar synthesis shows a signature of significant low-level convergence at 0.6-0.8 km above sea level (ASL). PAWR data show a coincident rapid growth of a misocyclone with top altitude increasing from 1.2 to 1.8 km ASL in two minutes. A small vaultlike structure with the maximum height of 1.3 km is formed following to the development of misocyclone with a delay time of about two minutes. One possible explanation is the role of vorticity stretching associated with horizontal shear instability. Fast and volumetric seamless observation of such a small spatiotemporal-scale phenomena opens up a way to progress our understanding of misocyclone that is of importance for convection initiation and severe weather phenomena.