I have zoomed in and cropped the image below. There is still a pronounced boundary to the heavy precipitation area. The precipitation scale is the same as in the earlier image in my last post. This is from a shorter range, high-resolution model. I think Flagstaff ends up in the 3/4 to 1 inch range. Notice that another boundary is forming along I-40 to the east. Stay tuned! There will be areas of Arizona receiving large amounts of precipitation over the next few days.