An area of low pressure that has been spinning near Hawaii and has picked up lots of moisture is going to move into the West Coast by Tuesday. By the time the precip reaches the dry air over the Sierra the amounts of precip that we see won't be much, but the moisture falling into the dry air will cool it until it reaches full saturation which will keep the snow levels near to just above base level for Tuesday. We should only see light snow showers with maybe an inch or two on the mountain.
Then forecast models are slowing the trough and bringing a second wave of precip later Wednesday into Thursday. The average of latest total precip output from the forecast models shows 1-6 inches for the base and 3-12 inches for the mountain by Thursday. and 3-6 inches at lake level by Thursday. By tomorrow we should be able to fine tune the snowfall forecast a little remove to reduce the large spread in forecasted snowfall amounts.
By the end of next week the ridge of high pressure builds back in bringing dry conditions through Thanksgiving. A few long-range forecast model runs suggest an inside slider could bring some colder air and light snow for Thanksgiving but others keep the ridge closer and us drier.
Stay tuned for updates on the coming snowfall....BA