I am so excited to be able to use that word in our first forecast of the season! And that’s exactly what we’ll be in for starting mid-late day Saturday, lasting through early next week. When we say storm cycle, we’re talking about a prolonged period where the large-scale pattern is primed for snowfall, and smaller features moving through this pattern provide the periods of heaviest snowfall. So the snow will be stacking up in spurts throughout this period.
Now for the details and uncertainty in this storm cycle. There has been great agreement in the computer models that we’ll be under the influence of a large upper-level trough sitting to our east throughout the period, putting us under a moist northwesterly flow. This type of pattern typically bodes pretty well for lots of snow in the Wasatch, especially the high terrain of Big and Little Cottonwood Canyons. The precipitation output by the computer models has agreed pretty well with this assessment over the past few days. However, as I mentioned above, the periods of heavy snowfall within the storm will come from smaller-scale features in the upper level pattern, and the structure and strength of these features is not well-predicted by the models at these kind of lead times (Monday is still 5 days away!). So as we get closer, the true strength of this storm will come into a little better focus.
To illustrate what I mean, here is a time-height cross section from the GFS model. Ignore a lot of the numbers and variables on there, and focus on the periods of green. These have varied quite a bit in the model runs, basically making the difference between a 1 foot storm and a 3 foot storm for Alta.
But I know everyone is looking for some numbers! So with the caveat that these numbers may change a bit as we get closer to the event, here’s my forecast. Drum roll…..I like a general 1-3 FEET for most of the Wasatch where you fine people plan to ski (8,000 feet and above). That said, I would not be surprised if the high elevations sites in the Cottonwoods exceeded these numbers.
Stay tuned for Jeff’s forecast tomorrow, as he’ll have some more certainty on the numbers. Jeff has also been realllly excited about the potential for a big dump from this storm for the past few days, so he is positively giddy to share his snowfall forecast.
There is still a ton of spread amongst the models and ensembles on the mid-late next week period, so the forecast confidence is fairly low, but it looks like we’ll remain in an active pattern after this storm. Keep those skis tuned!