NWS Forecast Office Tucson, AZ

That weather system that we have been following across Sonora Mexico will move northeast into Chihuahua Mexico today. Even though there is a slight increase in lower-level moisture into Southeast Arizona from the south, that departing system is just a bit too far away to impact the area today (with the exception of a weak shower across Cochise county). We are focusing our attention to our next weather disturbance moving south out of the Gulf of Alaska into the Eastern Pacific today through Thursday morning. It will then join with another weather disturbance in central California, then move across Southeast Arizona Thursday night into Friday. Given the fact that this system originated in the Eastern Pacific, it will have enough moisture with it to produce numerous valley rain showers, isolated thunderstorms, and mountain snowfall. Although the intensity of this system may change with time, at this time it looks like we will see a tenth to quarter inch of rain in the valleys and a third to half inch of precipitation in the mountains. The mountains may receive between 2 and 4 inches of snow.