Interesting week ahead…

Posted Wednesday, April 4th, 2018 by Mike Wessler

A quick hitting storm is lined up for the end of the week, with most of the precip occurring Thurs afternoon through Friday morning. This one will be the colder of two upcoming hits, with snow levels starting high, around 9200′ then falling towards 8000′. At only .3-.4″ of water for the upper Cottonwoods, this will put down 2-4″ of dense cream-cheese-like snow, with the possibility of light rain at some resort bases to start as temps fall. Upper elevations should remain all snow, but again, I’m expecting closer to 10:1 for this event.

NAM 12km meteogram for Alta Collins
NAM 12km meteogram for Alta Collins

The second event of note is this weekend’s storm, and as Trey mentioned it will be more of an atmospheric river type event, with ample moisture but warm southwesterly flow. The GFS meteogram hints at the problem: note the accumulating water but not snowfall, with temps at 700 mb just flirting with the 0 C mark. It is almost certain that resort bases (and possibly up to 11 k ft!) will see a prolonged period of rain to start the event. As the trough comes through and ushers in colder air, models suggest that the last 0.5″ or so of precip may fall as all snow. At a forecast 3″ of water, this has the potential to cause some major change to the snowpack. While the skiing inbounds could be okay on top of the new snow (elevation and timing dependent as event nears) the backcountry snowpack will likely be in a dangerous state.

GFS meteogram for Alta Collins
GFS meteogram for Alta Collins
An impressively wet GFS time-height plot showing the Friday quick hitter and the prolonged saturated column with the weekend's AR event
An impressively wet GFS time-height plot showing the Friday quick hitter and the prolonged saturated column with the weekend’s AR event

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