Thursday PM update:
Well, I mentioned this morning how important the 12z model suite would be in determining the track of the system for early next week. The models are in and it looks like the system is trending toward a farther west, then south track. 12z Euro trended toward the GFS. This would favor Southern Utah. Northern Utah will still see a good period of a moist, unstable flow that could bring at least some decent accumulations. Of course, there is still plenty of time for the models to backtrack… But for now, it’s not good news for Northern Utah.
Dry and mild Thursday and Friday. A weak system will approach the area on Saturday, bringing a chance for light snowfall, mainly to southern Utah, on Saturday night. A stronger system could bring mountain snowfall to the whole state late Monday into Tuesday.
Today and Tomorrow… Ridge conditions continue with warm (near record) temps on the mountains with relatively cool temps in the valley and plenty of haze.
A weak system splits on Saturday with the southern split expected to move into Southern Utah. This system will bring clouds and cooler temps to the whole state. Precipitation, however, looks limited to southern and central Utah. Even so, it will be meager with only a few light showers on Saturday night.
The more exciting system will move into the region on Monday. This is a consolidated, quick-moving system. I always think of these as “bowling balls”. It’s fairly potent, but the extent of it’s areal coverage is limited (consolidated) and it is moving quickly. It should pass through Utah Monday evening into Monday night. Today’s models are about 6hrs slower with the best precipitation than they were yesterday. This is important because instead of seeing most snow falling during the day Monday, it now looks like the best period for snow will be Monday evening. That moves the best ski day to Tuesday.
As for snowfall amounts, that is the tough party right now. If the track ends up being favorable for Utah as currently shown by the 0z EC, 0z GEM, and the 0z GFS, then we could be looking at 6-12″ in the mountains with perhaps a bit more in the Cottonwoods. However, the 06z GFS tries once again to drop the core of this system to our west and has it diving down eastern Nevada rather than passing overhead. Generally I prefer the more consistent EC (Euro), however the GFS solution also does have merit as it’s something that has happened before in similar situations. The 12z suite of model runs will be critical to knowing what we can expect.
We clear out after Tuesday of next week and it looks like we go back to ridging and valley inversions for at least 5 days. The long-range models still try to develop a trough over the region starting around January 19th. This is 11 days away from today and still very much just speculative…. but we can hope!
What needs to change to get the storms coming in consistently again? The obvious solution is to rid ourselves of this ridge. But how will that happen? I’m personally a big fan of using the MJO index. If you want to learn more about exactly what the MJO is, I suggest a quick google search for “Madden-Julian Oscillation”, you’ll find a great wiki page to answer your question. But from a forecasting standpoint, I’m most concerned with what stage it is in. The last two seasons the MJO has been almost a non-factor. Finally, over the last week or so, it has been strengthening. Unfortunately, it is strengthening in a bad phase for Utah storms. See below:
Currently in Phase 5, it is forecasted to start propagating eastward. We want to see it reach Phase 7,8,1,2,3…. As it is, stages 4,5,6 usually correlate to more western US ridging. The MJO is not the be-all and end-all for getting us storms, but at this point it certainly can’t hurt. I’m guess that as we approach favorable stages, we will stand a much better chance at ridding ourselves of such persistent ridging. As for our old friend El Nino, it looks like it will fizzle out as just a weak event. Not much fight in “the boy” this season.