I'll focus on the former, beginning with where we are right now.
Prior to last nights storm, snow cover in the Wasatch was scant. The Alta web cam at the top of Collins shows just a few patches of snow left over from last season.
As a result, Alta is covered by a blanket of white.
Passage of the trough will result in a lowering of snow levels to the valley floor Saturday night. The models are producing both orographic and lake effect snow in the post-frontal northwesterly flow late Sunday night and Sunday morning. The example below is from the NAM at 1200 UTC (0600 MDT) Sunday morning.
Models like the NAM don't adequately resolve the influence of the lake or mountains, but this is a scenario where the likelihood of lake effect is higher due to the relatively warm lake (about 11.5˚C) and forecast for a relatively cold and moist post-frontal flow.
Our downscaled forecasts based on the SREF are generating 0.25 to nearly 2.2 inches of water and about 4 to 35 inches of snow at Alta Collins through 1800 UTC 20 October (1200 MDT Sunday). For snow, most of the members lie between 10 and 20 inches.
Ultimately, the forecast distribution is one that I would describe as "heavily skewed." There is a high likelihood of something in the 6-10 inch range, but a long skinny tail of lower probability outcomes with greater amounts. Something on that long skinny tail verifying above 12 inches will require Alta to be in the cross hairs of well organized post-frontal convection or lake-effect.
The bottom line is that this is an event worth watching. A likely outcome is that the snow from this storm, combined with that from last night, will push the total snow depth to something like 10 to 16 inches by 1200 MDT Sunday. Given that's all relatively fresh, unsettled snow with a limited water content, it's certainly below my threshold for skiing, and it should be below yours too.
On the other hand, if all the ingredients came together — the trough track is right, the post-frontal and lake-effect convection goes big, and the central Wasatch are in the cross hairs — this could be a more significant storm.