A cold front that comes out of the north quickly is called a backdoor cold front. This front will move across Arizona tonight and into Saturday, bringing another round of snow, rain, and thunderstorms to the forecast area.
Please use the rain and snow maps here for the zoom-in projections for this event for your area – Backdoor Cold Front to Move Across Arizona Tonight into Saturday; Rain and Snow Maps – Arizona Weather Force
This front is not expected to be particularly strong across the northern half of Arizona early on, but as it reaches some instability for Maricopa, Pinal, Pima, Graham and Cochise County, we can expect strong growth, owning to higher precipitation totals.
As this moves southward on Saturday morning, we can see the chance of thunderstorms increase for the eastern half of Maricopa County, southward through Pinal County to Tucson and Cochise as well with the backside of the upper-level low working in.
Storms Saturday afternoon and evening will move from north to south, and the target location is off the Southeast Yavapai County and Northeast Maricopa County border, spreading south through Cave Creek, Rio Verde, Fountain Hills, Phoenix, Scottsdale, Mesa, Apache Junction, and the San Tan locations.