Tuesday PM update:
I know many of you are desperate for some fresh snow, so I figured it might be worth writing a short evening update to let you know the happenings of today’s model runs. This morning I mentioned there would be a weak preliminary system on Friday that looked like it wouldn’t do much more than bring some clouds and a slight chance for showers. Well that shortwave has been trending stronger in the GFS, and now especially in the 00z NAM. I’d like to see one or two more model runs before I call it a forecast, but we could get snow a bit sooner than anticipated on Friday.
Storm for later on Saturday into Sunday still looks good . . . Full update tomorrow AM
The good feelings continue with the general trend of models over the past 48 hours. Yesterday they were agreeing on the return of cold air, but disagreed on the amount of energy in the shortwaves dropping down out of British Columbia. Today, there is much more agreement and the general trend has been towards a more potent system for this weekend.
Today and tomorrow, a system to our West will move “through” us. Unfortunately, it is being sheared apart as we speak and we’ll only see some clouds tonight and tomorrow. The good news is that once that system passes to our east, it will allow the ridge to re-build, this time to our west over the Eastern Pacific. We’ve spent a lot of time over the past two season with ridging in the Eastern Pacific. What this ridge does is force storms to ride over the ridge and drop down through British Columbia, the Pacific NW, before dropping into the Rockies and Northern Great Basin. This pattern is a big reason why the Pac NW has done alright the last couple years, but by the time the systems reach Utah or Colorado, they’ve lost a lot of their energy. It also blocks more significant storms from moving on a west to east trajectory into Northern and Central California — this is why places like Tahoe, which rely on those major storms, have seen such poor winters the past two seasons (Yes, even worse than Utah).
This is a look at what the pattern will look like on Sunday according to the ECMWF (Euro):
Notice the amplified ridge of high pressure off the west coast, which forces a trough over the Pac NW and Northern Rockies. While this pattern isn’t great for major systems, it is good for us to get nice cold storms into Utah. That is exactly what I expect to happen this weekend.
As this trough digs starting on Thursday, temps will gradually cool as several weak waves pass through the area. We shouldn’t get much more than a few clouds and maybe a slight chance for light mountain snowfall through Saturday. Late Saturday into Sunday, things get more interesting as a much stronger system drops into the area. It is still too early to call it a definite forecast yet, but the models currently all agree, so hopefully this will pan out and we can get some snow.
Almost as valuable as natural snow this time of year is cold temperatures to allow for snowmaking. Luckily, that looks like a given with this pattern. So at the very least, we should have all guns blazing later this week and this weekend.