A deep trough of low pressure has moved in across Southern California and its counter-clockwise winds are pulling in moisture from both the Pacific and the Sea of Cortez. To the north, High Pressure is injecting cold air into the lower reaches of the trough, setting up significant snowfalls across the Desert Southwest.
Snow will likely coat the saguaros above Tucson and heavy accumulations may occur across the Mogollon Rim and atop the desert ranges of Southeastern Arizona. Moving eastward, the storm will then bring snow to the mountains and high deserts of New Mexico, southern Colorado and West Texas.
While pushing cold air into the Southwest Deserts, the zone of High Pressure, centered over the Great Basin, will also produce northeast winds across the mountains of southern California, a classic setup for Santa Anas.
