昭和58年7月豪雨の気象特性

Abstract

Heavy rainfall occurred on 20-23 July, 1983 brought about large disaster in the westernpart of Shimane Prefecture. Especially high rainfall rates stronger than 50 mm/h are ob-served continuously over the district for about 10 hours in the morning on 23 with the maximumdaily precipitation of 462 mm. Synoptic analysis on the heavy rainfall is made and some meteoro-logical characteristics are compared with those in the cases of heavy rainfall similar to this one.This heavy rainfall occurred in the warm sector of a weak cyclone over the Sea of Japan as aresult of convective activity, which originated in the inflow of warm and moist air due to thesouth-westerly low level jet stream. This type of heavy rainfall has not been seen in the district, though it has been seen occasionally in the Kyushu district. Cumulonimbus clusters were foundover the Sea a few hours before the occurrence of the heavy rainfall.