Winter’s Return

Posted Saturday, February 17th, 2018 by Trey Alvey

After a lovely bluebird Friday, Saturday should once again have great weather for skiing any leftover pow stashes. Temperatures will be a bit milder with highs in the 30s for most resorts. Without wasting any time I’ll get down to what everyone’s anxiously awaiting – our next storm!

Finally, a long awaited real storm will impact the Wasatch the tail end of this holiday weekend. In terms of clear weather for skiing I’d say Saturday is your best bet. Sunday shouldn’t be too stormy early, but by afternoon winds will increase and snow will move in as the trough approaches from the west. Overall, I’m not expecting too much precipitation with the pre-frontal period highlighted by the blue circle in the time-height below (Also important to note that time goes from right to left. The main event should begin with frontal passage (black circled area).

Screen Shot 2018-02-17 at 12.34.45 AM

Sunday night is when the big show begins – a cold front will slowly sag southward associated with an intensifying trough. A frontal band of precipitation will provide an initial burst of snow as 700 mb temperatures rapidly drop to -16 – -12 C, a very favorable range for dendritic growth. Also, the cold temperatures will means snowfall ratios near 20:1 after frontal passage – this will allow totals to stack up quickly and a return of Utah blower pow! Another factor in favor of significant snowfall is the speed of the trough itself. Because it’s expected to slowly traverse Northern Utah over a 24-48 hour period, the slow movement itself will provide ample opportunity for snowfall accumulation. I’d expect 6-12 inches by Monday morning and this is likely a conservative first stab.

ECMWF accumulated QPF through Tuesday night
ECMWF accumulated QPF through Tuesday night

Additional snow showers early Monday and into Tuesday are the other big wildcard. The period highlighted in purple (time height cross section above) features a fairly moist NW’ly flow regime. One potentially negative factor for significant accumulations is the relatively weak flow (albeit of a favorable trajectory) and temperatures may also be a little too cold for higher elevation areas. This could potentially put the benches – mid canyon in the most favorable regime given the extremely cold 700 mb temperatures and weak flow. Overall I’d expect at least an additional 4-8 inches in the period (though this could also be conservative). This is something that will certainly have to be monitored and refined in additional updates. The other big story will brutally cold temperatures below 0 on slopes at times Monday – Wednesday.  Regardless, early next week should have great powder days!

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