Salt Lake Swirly

Friday, October 11, 2013 at 7:42 am

Yesterday was a fun day meteorologically speaking.  As expected, Southern Utah saw the worst/best of this storm as the main Low pressure center passed through the south.  Here is a look at Eagle Point this morning:



Looks like it’s still snowing a bit, but that should clear out quickly today.  It’s hard to tell exactly how much is on the ground but I’d say it could be close to a foot.  Anybody down there that can report?

What happened in Northern Utah was truly fascinating.  A lobe of energy that passed through the Wasatch Front early yesterday morning headed west into the desert where it developed its own circulation over the GSL and started to pivot back toward the Wasatch Front / range.  This circulation over the GSL was affectionately dubbed, “The Salt Lake Swirly”, hence today’s discussion title.  The “swirly” was responsible for keeping precipitation going almost all day along the Wasatch Front yesterday.  Valleys saw .50″ to 1″ of rain but without much movement or forcing from this secondary circulation, precipitation had trouble making it high into the mountains or over the crest toward PC.  Still, areas of the Cottonwoods seemed to see at least a couple inches at the base.  Hard to tell exactly from webcams, but it looks like up to 6″ could have fallen on the upper mountain.  Overall, this storm performed as expected in S. Utah, and possibly over-performed a bit in N. Utah.

Today will be cool but mostly clear.  Saturday will be warmer before the next system moves in on Sunday.  This system is colder and has a very defined cold front that will bring widespread precip into Northern Utah by Sunday afternoon.  Snow levels should be around 6K feet behind the front, possibly lower.  The system doesn’t have a lot of moisture to work with, so amounts should again be just a few inches in the mountains with rain in the lower valleys.

The storm will keep showers around for Monday and maybe even Tuesday.  Models have struggled with next week a lot over the last few days.  Right now they seem to have agreed for the most part.  GFS Ensembles generally look a lot like the Euro now.  A ridge of high pressure is going to amplify over the west coast of North America.  Utah will be on the east side of the ridge.  Here is the progged jet stream locations in GFS spaghetti plots for next Thursday:



Our location on the east side of the ridge will keep us cool with cold air being funneled down from Canada.  It will also allow a series of very weak “inside slider” type systems to travel through the Canadian Rockies down toward Utah.  These systems generally have very little moisture to work with and get sheared apart by the thousands of miles of mountains they have to travel through to get here.  They are also almost impossible to time and forecast.  So it looks like next week with be cool with a chance for more weak systems to bring us clouds and showers, but at this point, the details are impossible to forecast.

Still some suggestion that the ridge will retrograde into the Eastern Pacific around the 20th of October and allow stronger systems to possibly enter the area . . . We’ll have to watch.

Enjoy the continued active weather!  Ski season is almost here!


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