Winter Returns (Sort of)

Yesterday we tied a record for April 4 with a maximum temperature of 79˚F at the Salt Lake City International Airport.  Impacts on snow aside, the weather was about as delightful as it could be in early April.  It's a bit of a shame we can't bottle up a day like that and open it up in mid July.  

It was very warm in the mountains as well with Alta setting a new maximum temperature record of 58˚F.  

The heat has done its damage as several SNOTEL sites have seen declines in snowpack snow water equivalent, despite their relatively protected locations, indicating that the snowpack has ripened and begun to decline to melt.  Parley's Summit SNOTEL, which is on a north aspect, dropped from 15 inches on April 1st to 12.2 inches last night.  

Source: NRCS

Even upper-elevation Brighton saw a decrease in snow water equivalent.  This site is a bit sunnier than most SNOTELs, but this is a substantial drop for early April.  

That all ends after today, at least temporarily.  A strong cold front will pass through northern Utah later today.  The latest HRRR forecast has the cold front arriving in the Salt Lake valley around 0000 UTC (6 PM MDT) this afternoon.  Expect a breezy afternoon ahead of the front as well.  

I suspect it will be an exciting period with and following frontal passage due to the strong winds and the instability that accompanies and trails the front, which could lead to some thunderstorms.  

Overall, the system is one that has an upper-level low that is tightly wound and moisture is limited primarily to northern Utah.  Precipitation will likely be greatest in the northern Wasatch.  Our downscaled GFS snowfall product shows absolutely nothing south of the Provo-area mountains, 4-8 inches in Cottonwoods, and the heaviest snowfall in the northern Wasatch and Bear-River Ranges. 

Most members of the downscaled SREF for Alta lie between 4 and 12 inches. The large range partially reflects sensitivity to the track and structure of the close low.  A few have a skunking, but there are a couple that go for bigger amounts.  

I think the most likely amounts are 4-8" for Alta-Collins, but it could be less or more depending on the gory details.  Truth be told, these are the situations where I just plan on waking up in the morning and seeing what happened. 

After this storm, it will likely be dry with a return of spring through next weekend.  There are a couple of brush-by systems that maybe could bring a few showers, but that's about it.