A Pacific storm that will begin to spread across San Diego County late Saturday could produce enough rain and snow through Tuesday to significantly lower the threat of wildfires across the region, the National Weather Service indicated in an advisory. The system will produce sporadic showers in most areas and several inches of snow in the local mountains. The peak of Mount Laguna could receive close to one foot of snow. The heaviest rain will fall in the mountains and foothills. But forecasters said Friday that most of the county would likely receive an inch or more of rain. Showers begin late Saturday and there will be rain and snow off and on into Tuesday. That might not be enough to bring a complete end to wildfire season, but it will help, forecasters said. San Diego has only received 0.14 inches of rain since Oct. 1, leading to the driest start of the rainy season since 1850. The dryness has greatly contributed to the spread of wildfires throughout Southern California.