A fast-moving storm could bring 0.25 inches to 0.50 inches of rain to San Diego this weekend, along with a dusting of snow to the county’s highest mountain peaks. The National Weather Service says the system will blow ashore late Saturday and could produce scattered rain before midnight. But the heaviest rain will fall overnight and into the morning hours. Inland valleys and foothills are more likely to receive between 0.50’’ inches and 1 inch of rain. The daytime highs will be on the cool side: 62 degrees on Saturday and Sunday.