What a great night to be a weather weenie. Heavy mountain snowfall. Valley thunder and small hail. It doesn't get much better than that, unless we also got more post-frontal snow.
Let's start with the northern Wasatch. In the pre-frontal environment last evening, it was absolutely lit, with high radar reflectivities developing over the upstream lowlands and extending downstream over the Wasatch Range.
During this period, Snowbasin's Boardwalk site recorded 0.86" of water-equivalent snowfall in two hours. I looked at their snowcam and inferred a 4"/hour snowfall rate. Total overnight snowfall reported by the resort was 18", with 1.99" of water equivalent at the Boardwalk site. That's great high-density base builder and just what we need in November.
Moving to the Salt Lake Valley, the front came through with a strong convective line, lightning, and thunder (apologies for the change in radar color scale, but it's early on a Saturday morning).
The rumblers woke me up, but a meteorologist never complains about being rousted by weather. Pea-sized hail pelted our windows and remained on our porch this morning.
If one were to complain about this storm, it left my place with minimal accumulation as things shut-down quickly in the post-frontal environment. C'est la vie.
Finally, moving to the central Wasatch, the Utah Avalanche Center reports 7-15 inches of snow with 0.8-1.5 inches of water. Alta-Collins sits at 15" on the interval board and is up 8 inches in total snow depth. The 0.96" of water recorded by the gauge is probably low due to the strong winds.
If you're thinking of ski touring today, keep in mind that (a) Alta is now closed to uphill, (b) the UAC rates the hazard as considerable, and (c) its really windy up there. I just took a look at observations at crest level in the central Wasatch and at one site it has been gusting over 86 mph, with a peak of 99 mph, since 11 PM yesterday.
We'll see some mountain snowshowers today that will taper off this afternoon. Accumulations of maybe an inch or two at best, unless a strong squall develops.
The models have backed off on the system for tomorrow, shunting it mainly to the north. Maybe some snow showers with light accumulations in the central Wasatch. An inch or two if we're lucky. Less is more likely.
If you like wind slab and don't find enough of it today, wait until Tuesday. With an approaching trough, the GFS is advertising increasing flow with the dreaded flags on the wind barbs at 700 mb (10,000 ft) penetrating into northern Utah by 0000 UTC 18 November (5 PM Tuesday).
Those represent free-atmosphere winds of 50 knots or more. Expect more wind redistribution.
Hi Jim
ReplyDeleteI have lived in kamas for a few years now and I'm trying to figure out what set up I should look for to expect a heavy snowfall here. I have for the life of me not been able to pin point any specific scenario. What would be your thoughts? Sw flow, nw, ....
I've never paid much attention to Kamas and what happens there. It's a tough spot as it is surrounded by higher terrain. If I had to guess, I would probably look for moist, stable flow situations with flow fro the south, but that's a guess.
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