The heavy torrential rain which happened in Northern China during August 3~5 in 1996 was the result of the stationary meso α cloud cluster within the typhoon low outside lane. The generation and development of the meso α cloud cluster were interacted by three air flows:1) low level easterly dry cold airflow, 2) low and medium level southerly wet warm jet stream, and 3) sub tropical upper jet stream. The mesoscale disturbances within the meso α cloud cluster were frequent. The disturbance caused by the meso β easterly wind shearline occurred three times or more while the disturbance caused by the mesa β low pressure occurred two times or more. The heavy rain cluster was accompained by meso β low pressure motion. The rain cluster stagnated more than 14 hours at the western mountain area of Shijiazhuang, where it brought 670mm rainfall in 36 hours. The heavy rain was centered at the windward slope and bell terrain near 500m sea level elevation.