I find the Ice Breaker to be itchy, but the Smart Wool micro weigh base layers are perfect. But I think even those would be too warm for when it gets to 60-70, if you have something over it. I lived in Tempe for 16 years and I know exactly what you are talking about. I would go with a Craft short sleeved or sleeveless base layer under a regular jersey, with arm warmers and a jacket, so you can remove the layers as it warms up. If you are going out only in the morning, then I would wear the micro weight wool as a base layer; I think they have short sleeved versions, so you might try that under your jersey.
I know that I always left my coat and gloves at work in the afternoon, because it was hard to remember a winter coat, when it was 70 degrees when you went home!