Wednesday PM update:
Latest model runs have been digging both the front tonight and the Low pressure system this weekend deeper than before. I mentioned a strong possibility of this happening earlier today. Right now, the front is progged to stall just south of SLC instead of north. That might shift the band of precip from the Northern Wasatch to the Cottonwoods and Park City. Even if this band sets up right over the Cottonwoods and PC, I don’t see huge amounts. Right now, 2-5″ is possible with a chance for more directly under the stalled front. Precip in the lower valleys should fall as rain. It’s impossible to predict exactly where this front will end up, so don’t be surprised if your resort of choice tomorrow isn’t boasting tons of fresh powder.
The other trend is to dig the Low even deeper — this should come as no surprise if you read the discussion this morning. What it means for us is just moderate snowfall for S. Utah with light amounts for the Wasatch on Friday night into Saturday. It looks like 3-day totals will end up in the 6-12″ range for S. Utah, and 3-6″ in the Wasatch with perhaps pockets of slightly more. Unimpressive. Next week will be dry until at least Wednesday, then we may start a slow trend toward a more active pattern during the second half of the month. The PNA going negative could have the same effect the MJO had for the end of February.
Details remain the same from yesterday’s discussion, so today I’ll just focus on snowfall totals that we might be able to expect rather than the details.
Tonight’s front looks to stall just north of SLC in a line extending roughly from Wendover to Logan. This, as expected, will bring the heaviest snow to the Wasatch mountains north of I-80 where the NWS has posted and Winter Weather advisory. Generally speaking, I’d expect them to get 3-6″ with up to 10″ in local pockets directly under the stalled front. Hopefully tomorrow will be a powder day for Snowbasin and Powder Mountain, but confidence is low due to the unreliability of a fairly weak front stalling. South of the stalled front, in the Cottonwoods and PC, don’t think we’ll see too much tonight and tomorrow. Off and on light snow in the mountains with rain showers in the valleys. Accumulations should remain below 3″ unless we get lucky with the front drifting farther south than expected before stalling.
The cut-off low will then start tracking through the desert SW on Friday and Saturday. Latest runs have moved the Low farther south. I feel like this is often the case with cut-off lows, they tend to drop farther south than the models initially indicate. I blame Newton’s basic laws of physics for this, “an object in motion tends to stay in motion”. When a Low pressure system cuts-off, it takes a lot to get it to start tracking eastward again, and with limited jet dynamics to push it along, models tend to underestimate just how far it will drift off course before eventually turning east again. If the Low does end up tracking through S. Utah, they will have a fairly major winter storm and the Wasatch will get enough moisture pulled up to do alright as well on Friday/Saturday. However, if the low tracks through Arizona, S. Utah will have a moderate storm and the northern half of Utah will see very little in the way of snowfall. It is a really difficult call.
The overall message is this… Tomorrow the Northern resorts (Snowbasin, PowMow, Wolf) should have the best chance at some fresh snow. On Friday and especially Saturday, Brian Head and Eagle Point should do well and it might be worth a road trip if you’re itching for some freshies. The big question mark is Friday and Saturday in the Wasatch. If we get unlucky and the stalled boundary is too far north and the low tracks too far south, we may end up with only a few inches over a three day period. However, there is also the possibility of us getting some good luck with the frontal boundary and the track of the low, in which case the Wasatch could get 10-18″ by the time all is said and done on Saturday evening. My guess is we will be somewhere in between with 3-day totals of 5-10″ for most resorts in the Wasatch. Not overly impressive.
The long-range is a mess right now, GFS is now looking a lot like yesterday’s 12z run of the Euro and the Euro is looking more and more like yesterday’s GFS. As I said yesterday, let’s give the models some time to figure things out before we lose sleep over it. It will be at least the middle of next week before our next chance for snow. CFSv2 has actually been showing a wetter than normal pattern for the west for the latter half of March. I’m not sure how much I trust the CFSv2, but let’s hope it’s on to something.
On a non-weather note, WSF has now had over half a million visits this winter. I’m pretty sure some of you think you’re directly responsible for at least half of those visits. 🙂 Thanks for trusting me to decipher our complicated WX patterns.