In December, a very deep trough of Low Pressure brought lots of snow to the Flagstaff and the S.W, and even to some of the lower deserts, including Yucca Valley, California. Many roofs collapsed in Flagstaff due to the December snow - 47" total from about Dec. 15th to early January!
However, since then, the entire S.W. has been under a very strong upper level ridge of high pressure since early January. Flagstaff has experienced above normal daytime temps and gorgeous sunshine. Some cold fronts will bring a chance of snow to the region within the next week or so.
Just drove from Phoenix to Flagstaff this very warm afternoon and there is no snow whatsoever until about 25 miles south of Flagstaff on I-17 just south of Munds Park.
National Weather Service maps days 3 to 7:
HPC Medium-Range Forecasts (Days 3-7)