Features of the Convective Rinfall Synstem over the Northern Area of Shimabara Peninsula on 18 November 1994

A convective rainfall occured on 18 November 1994 over the northern area of Shimabara Peninsula in Nagasaki Prefecture is studied by the research of rain-gauge and an RHI rader observation. Main results are as follows. (1) The rain echoes appeared at the central region of Nagasaki Peninsula at the first stage. They then moved eastwards to the northern area of Shimabara Peninsula and brought a strong rainfall there. (2) The second rain echoes, which attacked the same area more strongly, originated on the sea (Tachibana Bay) between Nagasaki Peninsula and Shimabara Peninsula at the west end of the foregoing echoes. As a result of this, the rain echoes grown up in a band shape of 35km long and 5km wide. (3) All the active rain echoes moved from WSW to ENE (N60°E) with a velocity of 45～50km/h. Their direction and speed almost agreed with those at the levels of 500～700hPa of the nearest upper air stations (Fukuoka and Kagashima). (4) The features of this rainfall suggest the enhancements of rain-cloud generation by the orographic effects of the Nagassaki Peninsula