The biggest change to the forecast is slowing down the progression of the cold front as it move through on Tuesday. Since the cold front is the main producer of the snowfall that would prolong the snowfall slightly and increase amounts slightly. All of the forecast models have increased the precipitation forecast by about a quarter of an inch. That is not much of an increase but with the really cold air moving in it would increase the snowfall forecast by a few with the high snow ratios.
The winds are starting to pick up as the front moves down from the North. Snowfall could start as early as midnight, but the heaviest snowfall is expected Tuesday morning. With the slowing of the front snow showers could stick around through Tuesday evening. Forecast totals are now 5-9 inches for base, and 8-12 inches on the mountain.
It stays cold with high temps only in the 20's into the weekend so that would allow around the clock snow making. Lows at night in the single digits to below zero at the base, especially with the fresh snowcover.
Another weak storm is going to slide down the West Coast and then inland Friday night. The question is how long is it over water before coming inland and how much moisture can it pick up. Some forecast models have it coming inland over the Pacific NW like the storm today and then sliding down over the Sierra similar to Tuesday's system. That would bring another 3-6 inches Friday night. One of the forecast models has it over water a little longer and coming in over Northern CA. It has up to an inch of liquid with that scenario. It's something to watch as the Canadian would bring in amounts closer to a foot.
Over the weekend a ridge of high pressure starts to build over Alaska or just South in the Gulf of Alaska along 140w. The jetstream is going to try and cut under the ridge into CA on Monday to bring us a quick hitting system. Some forecast models have the ridge pushing South on Monday as low pressure moves into the Gulf of Alaska. That would either block the storm or push it into Southern CA. Other forecast models have been consistent with bringing the system straight into North/Central CA with a direct hit on Tahoe. With the forecast models not agreeing confidence is very low right now. We could either get nothing or 1-2 feet so we will continue to watch this storm.
Looking at the very unreliable long-range models (especially as of late), the trend is for retrogression and flattening of the ridge off the coast later next week possibly allowing some more storms into CA as we head towards mid-month.