Characteristics of the Meso-scale Environments of Storms Associated with Typhoon-spawned Tornadoes in Miyazaki, Japan

Abstract

In order to elucidate meso-scale environmental characteristics contributing the generation of a typhoon-spawned significant tornado (F2) occurred in Nobeoka of Miyazaki prefecture, Japan in 2006, environmental and composite parameters in Miyazaki are examined in comparison with typhoon-spawned 3 tornadic events in Miyazaki and 16 nontornadic events using the forecast dataset of the operational nonhydrostatic mesoscale model of the Japan Meteorological Agency (JMA).
It is found that the significant tornado in Nobeoka is accompanied by enhanced convectively unstable environment with large vertical wind shear, which is represented by a relatively large convective available potential energy based on mean parcel in the lowest 500 m layer above ground level (AGL) (mlCAPE) and significantly large shear parameters (e.g., storm relative helicity; SRH) compared with other tornadic and nontornadic events. We also discuss synoptic condition producing these characteristic environments along with the comparison of the environment for the tornadic supercells and hurricane-spawned tornadoes in the U.S.