Colder Air Is Coming

With the end times near, today would be a good day to get out and enjoy the mild fall weather.  It should be sunny and warm by seasonal standards.  Tomorrow will be colder, a harbinger of things to come.  

The first blow to mild fall weather comes this evening in the form of a cold front that the HRRR forecasts to be moving through Salt Lake City at around 0400 UTC (10 PM MDT).  

The front will spread across Utah tonight and tomorrow, with strong northerly to northwesterly flow and colder air in its wake.  

The National Weather Service forecast highs for the Salt Lake City International Airport today and tomorrow are 72˚F and 52˚F, respectively.  A bit of a breeze will make the change feel even more dramatic. 

Then the weekend is "interesting."  First, we have a brushby system on Saturday.  The GFS forecast keeps most of the precipitation to our north and northeast, with just a few light valley showers and high-elevation snow showers.  

A consult of our SREF downscaled precipitation product shows a sharp contrast in precipitation probabilities from the Wasatch Front to the the northeast corner of the state.  

The plumes for Alta Collins show that 23 of the 26 members produce less than 3 inches of snow through 0000 UTC 25 October (6 PM MDT Saturday).  Three go for 3-6.5 inches.  

With the GFS producing paltry amounts and the Euro also producing light accumulations, the odds are stacked for this to be a dust on dirt event, with about a 10% chance we see more than 4 inches.  

Snowmakers will be happy though as we see some cold October air pour into the state Sunday and Sunday night.  The forecast below, valid 0900 UTC (0300 MDT) Monday shows 700-mb (10,000 ft) temperatures down to -14˚C!

That's not record setting territory, but it is cold, and it will produce temperatures in the single digits at 11,000 feet.  This will be a good opportunity to test out the snow guns.