The tail of a potent Pacific storm is dropping snow across the San Diego County mountains and rain virtually everywhere else on what is expected to be the final day of nearly a week of cool, stormy weather. The National Weather Service predicted up to 8 inches of snow would fall in the mountains and as much as 6 inches in Julian. There could be up to 2 inches at the 2,500 foot level, forecasters said. The system also was expected to drop a quarter-inch of rain at and near the coast, and twice that across inland valleys and foothills, adding to the fall and winter bounty.