Thursday AM update:
Models have fairly decent agreement that an end to dominant ridging will take place later next week. GFS has abandoned the idea of undercutting moisture and now agrees with the Euro on flattening and retrograding the ridge starting the middle of next week. This will lead to a chance of snow in northern Utah. Right now it looks like the main storm track will remain to our north at least initially but could start to sag south toward the end of the month. I’d expect, at the very least, a chance for light snow for the northern mountains of Utah on Thursday (Jan 24th), but it’s still unclear if this will be a strong enough system to clear out inversions. For right now, it’s a step in the right direction so we’ll take it. WSF
The inversion is really starting to strengthen as temperatures aloft have been rapidly warming. Expect high temps at 11,000 ft to be well above normal for the rest of this week as temps in valleys remain well below normal. We’ve already started to see a decrease in valley air quality over the last couple days and it will only get worse as time goes on. Time to try to do as little driving as possible to help mitigate the polluted skies.
Now moving on to the question on everybody’s mind: when will see our next chance for snow? The valleys might see light inversion flurries at times, especially at night, that some of our readers have referred to as “pollution/toxic snow”. But in the mountains, it’s still not going to be in the next week and there’s very little chance of it in the next ten days. There are essentially two theories being put forward by the two main global models. The ECMWF (Euro) has been showing a gradual retrogression of the ridge into the eastern Pacific, starting around January 25th. This would mean that colder (relative to the GFS) systems might drop down into the region by the end of the month. The GFS, however, has at times been favoring the idea of retrograding the ridge a bit and amplifying it, allowing sub-tropical moisture to undercut the ridge. This idea starts to take shape around the 25th as well and would also give us a chance for precipitation by the end of the month, however in this type pattern, we would see higher snow levels and denser snow.
General trends seem to favor the Euro at this point. The GFS, which was showing full on undercutting a couple days ago, has backed off for the most part and seems to be trending toward the Euro’s idea. Hopefully, we’ll be able to get the best of both worlds, cold systems that tap into tropical moisture. CFSv2 is useless at this point as it has bounced back and forth between above and below normal precip anomalies for this time period for the last two weeks.
The MJO, which has been relatively quiet so far this season is at moderate strength and on the move. It is just entering phase 7 and is progged to weaken and move into phase 8 over the next couple weeks. Often, phases 7 and 8 can help force moisture into the west coast so it is worth noting. My current guess right now, all things considered, is that we’ll start a transition to a new pattern around the 25th of January. It’s still too early to really know exactly what type of pattern will take shape beyond then, but the general feeling is that any change will be welcome after what will be 2 weeks of no snow and stagnant air.
Be patient and get to the higher elevations if you want to avoid the nasty air and cold temps. As always when we are trying for forecast 10+ days in advance, take everything we are saying as exploring the possibilities rather than a concrete forecast. It will all become clearer as time wears on.