This study used MM5 mesoscale modeling to analyze the influence of regional atmospheric circulation on flooding of the Ethiopian highlands from 26th-28th of July 2006. It had been found that the northern, south western and the central highlands of the country had showed large amount of precipitation and cloud cover in comparison to the lowland parts of the country, in the East and South east, due to the effect of topography and regional weather systems. Investigating the effect of topography on precipitation reveals that there was a clear reduction in the amount of precipitation and a shift in the pattern of precipitation, when topography height was reduced by 50%. While topography had increased by 50%, no clear pattern of precipitation had been revealed. In general topography and regional weather systems play a great role in the amount and spatial pattern of precipitation in the region.