Sunday AM update:
OK, we are on the eve of the start of the first winter storm pattern of the year. Tomorrow afternoon the initial front will drop south into the region, if you remember our discussion from a couple days ago, this is the front that will sort of “stall” over Northern Utah. Best dynamics will depend on it’s exact position tomorrow. If it stalls north of SLC, the Northern Wasatch including PowMow and Snowbasin will see the best lift and moisture stream. If it stalls a little farther south, PC and the Cottonwoods will be favored. Unfortunately, the prefrontal airmass will be quite warm today and early tomorrow, and with the slow progression of the front, it will take a while for cold air to get into the mix. This means that snow levels will start out at about 9,000 ft. tomorrow afternoon and only gradually lower Monday night before dropping rapidly late on Tuesday. However, by that time, much of the good dynamics associated with the front will have moved south and east. Still, looks like the initial front will bring 4-8 inches above 8,500 ft. by Tuesday night. After that, the parent low will start to kick its way inland and will eventually reinvigorate precip for Wed night and Thursday. By then, we will all be in the cold pool and snow levels will be down to most if not all valley floors. We could reasonably expect to see another 4-8 inches in the high elevations from this moisture associated with this parent low. Snow may accumulate at times in the lower valleys as well but with warm pavement temps, don’t expect too much road accumulations. Park City valley locales should see a few inches by Thursday evening.
So overall we are looking at 6-14 inches for the high elevations by Friday with 5-10 inches for PC resorts and even a dusting possible down to SLC valley floors later this week. Keep in mind that these are conservative estimates. Early season storms especially are notorious for being disappointments so we’re avoiding overhyping snow amounts. But be aware that the possibility does exist for more snow than we are currently forecasting if everything holds together. Beyond the work week, it looks like the Jet will retreat a little to the north for at least a few day allowing for a modest drying and warming trend.
Another positive factor about this storm is it is warmer getting colder so we’ll have the wettest, heaviest snow on the bottom with the lighter stuff on top. Very stable base.
We will also see our coldest temps of the season later this week with hard freezes likely everywhere in Northern Utah. So it may be time to take the appropriate winterization steps if you haven’t already done so.
Full update tonight!
Saturday PM update:
Updating just to push back the timing of each wave by 6 hours or so as both EC and GFS are coming in slower. This means the first main wave on Monday will arrive mostly in the evening/overnight hours into Tuesday and the second impulse looks to affect N. Utah mostly late on Wednesday into Wednesday night. Showers will likely continue, particularly in the mountains, between waves. Other update is to temps, 12z runs came in colder and thus it’s looking increasingly likely that snow levels will lower to all valley floors in Northern Utah. Don’t expect more that a dusting on grassy surfaces for the valleys but it does mean better snow ratios for the mountains. 6-12 inches between Monday-Thursday above 8K feet still sounds reasonable but it is certainly not out of the question that we could see more than that if everything sets up well.
Saturday AM update, 6 AM:
Everything is starting to look a little clearer through at least Wednesday of the upcoming week. The Wasatch and adjacent Wasatch Front will see its first real winter pattern this week with one large Low sending in reinforcing impulses every 24 hours starting today. Today’s impulse will do little more than bring in some clouds, winds, and slightly cooler temps. Tomorrow’s will be a little stronger with a slight chance for showers. The first real threat for accumulating snowfall will start on Monday in the mountains with rain showers in the valleys below 6,000 ft. At this time it looks like rain and snow will increase in intensity on Monday into Monday night before clearing out Tuesday morning a bit before a reinforcing wave of energy picks things up a bit on Tuesday evening through Wednesday. This latter impulse could be strong and cold enough to bring snow levels down to SLC valley floors, or at the very least, to the bench locations.
None of these waves are particularly strong. But the extended period of precipitation possible for the mountains will allow for decent snowfall accumulations. At this time it looks like 6-12″ will be possible above 8,000 ft by Thursday. Essentially 1-3″ for every 12-hour period from. Monday night-Wednesday. So it’s not a major storm at all by Wasatch standards but it is a very “winter-like” pattern, which is encouraging considering we saw so few of these early last year.
After Wednesday, the models still haven’t fully figured out what to do with us. But latest trends indicate a chance for at least light mountain snow continuing heading into the weekend.
Here is a clip from the NWS forecast for Alta, UT, it highlights the extended nature of this system and how the chance for snow will continue through then entire week:
In fact the chance for snow now extends well beyond this, so just imagine about four more of those “Chance Snow” icons extending toward next weekend. Winter’s almost here. Let’s just hope it delivers.
Friday AM update, 9:30 AM
EC and latest run of the GFS both slow down the progression of the initial front, with it not moving moisture into the area until late Monday. Still lots of questions with the second wave of precip for midweek. It’s an incredibly difficult pattern to forecast that’s for sure. So for now lets just leave it at unsettled Mon-Thurs with valley rain showers and mountains snow off and on. Total accumulations should be 6-12 inches above 8K feet and possibly more if things work out for us by Thursday of next week. Models diverge drastically beyond Thursday with another trough in the EC and a ridge in the GFS. Stay tuned . . . Mother nature is testing my sanity early on.
Friday, Oct 19, 2012 12:00:00 AM
We haven’t posted a full weather discussion over the last few days and instead focused on quick updates for two reasons. Firstly, on Monday and Tuesday the models struggled so much with finding a solution to next week’s pattern change that it was almost pointless to post as it would have been irrelevant by the next model run. Secondly, once the models finally did agree on a broad solution, they weren’t too different from what we had originally forecasted on Sunday night so there wasn’t really a need to update. In fact, the only reason I’m updating now is that I’ve finally crossed the impossible-to-define threshold where we finally feel comfortable enough to talk specifics about next week, including what you’re all wondering, how much snow we can expect.
So let’s get down to it, shall we? The next few days will be absolutely perfect Fall weather with leaves changing now in the lower valleys. Great time to get a last few mtn bike rides in before some of the single tracks we all love get covered in snow and/or mud. By Sunday, clouds will be on the increase and breezes will be picking up. A cold front is going to rapidly drop southeast toward Utah during the day Sunday before stalling over Northern Utah on Monday, basically pointing a bullseye over the Wasatch. While it is not overly cold or moist, a stalling front means an extended period of precipitation. Good news! Models have been remarkably consistent with this feature for the past 72 hours or so. With that being said, if the front stalls just a tad farther north or south of where it is currently progged, it could drastically influence how much precip we see. So we will have to keep an eye on how that plays out in the models through the weekend and I’ll be curious to see how the NAM handles it once we get within range (NAM is a short-range model). It could be once of those situations where we don’t know until it gets here. But at this time, it looks like valley rain and mountain snow above 7,500ft looks likely starting early on Monday and perhaps continuing off and on through Tuesday AM. There is a chance snow levels could go lower than that but we’ll go conservative at this point. As for snowfall estimates from this particular initial front on Monday, we are going to guess 3-6 inches above 8K feet with the potential for significantly more if the front stalls out just right. It’s a big ” if “ at this point.
After the front slowly weakens and dries out on Tuesday, we expect a bit of a break as the main Low pressure system establishes itself off the coast of Oregon. We will likely be in a decently moist and cool westerly flow on Tuesday so orographic showers in the mountains are a good bet but nothing major. The latest 00z run of the GFS was much stronger and deeper with the main Low, bringing a vast swath of QPF (precip) into the Great Basin and Northern Utah. Earlier runs of the GFS showed the main energy being forced north once the Low finally kicked inland. Because this is a new run and we haven’t seen the 00z Euro yet, we aren’t sold entirely on this scenario. If it were to verify, we would be looking at a significant winter storm for Wednesday and Wednesday night of next week. We may also see the first snow for the SLC valley floors, as it just may be cold enough. We’ll have to watch and see. Here’s a look at what the GFS paints for total precipitation for the next 8 days:
As you can see, the latest run shows well over 1″ of liquid precip for the Northern Wasatch by late next week. That generally equates to about of foot of snow.
The big take away from all of this is that this is our first Winter-like pattern of the season. The type of pattern that could put down a decent base at area resorts if it all works out. Earlier storms this season were “teasers” that put down a few inches of snow that melted away within a day or two. This is giving every indication of being the real deal. Yes, there are a lot of questions as to details and exactly how much snow we’ll get but it’s our guess that by this time next week they’ll be a foot or more of new snow in the highest elevations of the Wasatch.
So get STOKED, we’re going to be ripping through our beloved Utah powder before we know it!