Saturday is a weather alert day across Northern California as a low pressure system moves across the area, bringing rain, mountain snow and gusty winds. The heaviest rain will fall during the morning hours of Saturday, and some valley locations could see an inch or more of rain, with the highest amounts occurring north of I-80. The foothills could see up to 2.5 inches of rain. Snow depths will be over 5,000 feet Saturday with snow accumulations of up to 2 feet possible, with even higher amounts near the peaks. The drive through the Sierra will be very difficult and chains will be required. In addition to rain and wind, we will have to contend with gusty winds that could create whiteout conditions in the Sierra and make driving conditions even more difficult. Gusts could reach 55 mph, potentially causing downed trees and branches and power outages. Rain in the valley and foothills should stop by early afternoon, but snow will continue in the Sierra throughout the day. Precipitation will end towards the evening, but frost and fog will be possible in places tomorrow morning. Another chance of rain and mountain snow is forecast for Monday morning.