Snow Much to Be Thankful For!

Posted Wednesday, November 27th, 2019 by Taylor McCorkle

Happy Thanksgiving Eve to all our fellow snow lovers! We are thankful for each and every one of you!! We are also thankful to have our website BACK IN BUSINESS!

As I’m sure you all have noticed, we have one heck of a storm underway. This potent snow-maker will keep cranking until Saturday, making the first full weekend at many resorts one for the books. Let this serve as your “Too Long Didn’t Read” section, but let me tell ya, you’re gonna wanna read it all.

Snow has been persistent since this morning, but was slightly impeded by downsloping easterly winds. These downslope effects cause the air to dry and warm as it descends the terrain, creating a dry layer near the surface which allowed for some sublimation of falling snow. This easterly wind has since stopped, so the lower layers will be able to adequately moisten and support sustained snowfall.

Wind observations from a station on the U of U campus. Plot via mesowest.utah.edu

Meanwhile, it has been DUMPING in the mountains.. About 8″ of fresh snow has fallen at Snowbird and Alta! Similar amounts have been reported from our friends a bit further north at Snowbasin. And the best news of all is we’re just getting started..

Snow pillow snap shot via webcams on snowbird.com

Forecast for Wednesday evening – Saturday morning:
A moisture-rich, slow-moving trough will make its way across the state over the next few days, bringing several rounds of heavy snow to both the valleys and mountains. The National Weather Service SLC has issued a winter storm warning for the entire county warning area.. With today being one of the highest-volume travel days of the year, please proceed with caution!! Driving carefully and slowly will help ensure you arrive safely to your destination. Or best of all, avoid travel completely if possible.

Currently, the center of the closed low associated with this storm is situated to the west of Utah. This synoptic environment is the source of the predominately south-southwesterly flow aloft. This moist, southerly flow has helped to somewhat moderate temperatures today, keeping the valley floors at or near freezing. This advection of “warmer” moist air is creating some instability at mid-levels allowing for the potential for convective snow showers into the evening hours. This is shown by the time-height cross section below from weather.utah.edu

Over the next 24-36 hours, the trough will slowly move eastward. Beginning late tonight into tomorrow morning, the snow will be thermally forced by a 700-mb convergence zone that will extend southwest to northeast across the state. This boundary is along the easternmost edge of the upper-level low, which will stall in its eastward progression for a time tomorrow.

12Z ECMWF forecast of 700 mb temperatures, valid Thursday 9 am.
Plot via maps.weatherbell.com

Thursday night into Friday, the trough will finally eject across Utah and undergo some strengthening as it moves out to the northeast. Periods of moderate-to-heavy snowfall will be expected throughout the day on Friday. As the trough exits the region, northern Utah will enter the West-Northwest flow regime of the cyclone, which will allow prolonged snowfall to occur in the mountains, predominately in favored geographic locations such as Big and Little Cottonwood canyon. Drier air will move in by late Saturday, shutting off some of the bonus orographically-enhanced snowfall.

So you came here for the snow totals, huh? Well, we have those for ya. Here’s what the consensus is through Saturday:
Cottonwood Canyons: 28-40″
Ogden resorts: 24-30″
Park City resorts: 12-20″

And for fun, here’s the latest simulated reflectivity from the NAM 3 km from maps.weatherbell.com

Enjoy!

-Taylor

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