The plains of Gunma and Saitama prefectures have a high density ground surface meteorological observation network consisting of POTEKA weather stations with around 150 points and a resolution of approximately 2 km. These plains have a climatological feature that a cumulonimbus is generated over the surrounding mountains and proceeds over the plains with the growth and causes gusts such as downbursts and gust fronts in the summer. The high density ground surface meteorological observation network has succeeded in observing 13 cases of gusts, which included 5 cases in the F1 category (Fujita Scale) and the JEF1 category (Japanese Enhanced Fujita Scale) for about 6 years since July 2013. In the downburst cases of the F1 on June 15, 2015 and the JEF1 on July 14, 2016 which were substantially damaging, the localized transition of wind direction / speed was observed. Moreover, it was confirmed the sign of the divergent wind by the downdraft of downburst.