A Ribbon of Rain from Tijuana to Oregon

My wife was headed off to the store and called and asked me if it was raining here because she saw some rain clouds. So, I checked online to see what to expect with a (within 5 to 10 minutes) live radar feed of California and Oregon. What I saw surprised me because there is a ribbon of rain storms from Tijuana all the way up through San Diego, Bakersfield into the Sierras and Yosemite on up into ORegon. And what is really strange is some little rain clouds also in Arizona, Utah, Idaho, Nevada and Wyoming as well. Must be monsoon weather that we get coming up through the deserts this time of year that keep all the cactuses alive year around.