UPDATE: Pineapple Pow Part Deux

So the unstoppable force (Pineapple Express/Atmospheric River) is still on track to ram head first into the immovable object (Sierra). Who is going to win? WE ARE! And we are winning with the first proper snow dump on the Sierra for the season (better late than never). So those tricky weather models are trying to keep it colder longer tomorrow and bring the cold air back a little sooner Sunday. They did this right before the last storm and got all of us forecasters to up our totals only to end up with egg on our face.

Figure 1: MAJOR rain and snow event coming to the Sierra over the next 3 days. Liquid precipitation totals will range from 4-7+" in the Sierra. And snow, 2-4 feet.

With that in mind, here's the update to the forecast. So the pessimistic, probably more practical forecaster in me thinks 6-12" tomorrow, 18-24" Saturday and into Sunday, and 2-4" Sunday night for a grand total of (drum roll).... ~2-3 feet of snow. The optimistic, probably more hopeful forecaster in me is believing the hype and has this breakdown: 12-18" tomorrow, 24-36" Saturday into Sunday, and 3-6" Sunday night for a grand and awesome total of ... 3-5 feet of snow. All in all, I think most areas (above 7500') will see a solid 2-3 feet of snow with the highest elevations pushing 4 feet (Figure 1).

The major key is the snow level. The moisture is there. The mountains are here. Instability (upward motion), which helps condense and freeze the water into snow is going to be good enough as well. BUT, and I mean a big BUT, like a Kim Kardashian sized BUT(t), is where the snow level sets up over the next 72 hours.

Figure 2 (above): 9-10000' temps, winds, and heights for tomorrow afternoon. Temps of -8 to -6 celsius equals a 5-6000' snow level
Figure 3 (below): 24-hour liquid precipitation totals valid 10 pm tonight through 10 pm tomorrow. 0.5 to 2" of liquid precipitation expected.

Tomorrow morning to tomorrow evening the snow level will be 5-6000' (Figure 2). Models are forecasting 0.5-2" of liquid precipitation, which we think will end up as about a foot of snow give or take a few inches above the snow level (Figure 3). 

The snow level then increases to 7-8000' Friday night to Sunday evening (Figure 4). This is when it really dumps. Models are predicting 2.5-5" of liquid precipitation, which we think will be 2-3' of snow give or take a handful of inches above the snow level (Figure 5).




Figure 4 (above): Same as Figure 2 but for Saturday afternoon. Temps of -4 to -2 celsius equals a 7-8000' snow level
Figure 5 (below): Same as Figure 3 but for Saturday morning through Sunday morning. 2-5" of liquid precipitation is expected


Finally, the snow level drops again to 6-7000' Sunday night and into Monday morning. Models are forecasting about 0.25-.50" of liquid precipitation, which we think will be 2-6" of snow above the snow level. 

The winds will be strong through the weekend so expect some lift closures or at least slowdowns (Figures 2 and 4). Also, with all the new snow and the variation in the snowpack, I expect some runs not to be open due to avalanche concerns. Hatchett, will get a post up after the storm to discuss the avalanche concerns from this storm.

We will keep updating here, on Twitter (@powdiction), and on Facebook through the weekend and into next week. Like I said, wax those skis and boards, and do not forget to call in sick Monday because it will be the best riding of the year!