Blocking Pattern Will Bring a Chill to Northern Utah

I confess that given the stay at home order, my desire for warm weather is unusually high.  In addition, my preference is to have ridging over Utah in April and May, which means comfortable weather, than June, July, and August, which means uncomfortable weather. 

Mother Nature will not be cooperating, however, over the next few days.

Instead, she is producing a highly amplified pattern at jet-stream level, which means persistent upper-level flow originating from the high latitudes.  Below is the 500-mb geopotential height forecast valid 0000 UTC 13 April (6 PM Sunday MDT) showing a high-amplitude ridge upstream of the Pacific coast of North America and a deep trough over central North America.

The transition to this pattern begins in earnest tomorrow (Saturday), with cooler air and showers moving in during the afternoon.  Colder air continues to move in Saturday night.  Sunday will likely feature high temperatures in the high 40s, with a slow recovering during the "work week" (whatever that means these days).  Below is the National Weather Service Forecast for downtown Salt Lake to illustrate the change.

Source: NWS

If you are planning a walk, hike, bike, or ski Saturday, I get a weather forecast update from the National Weather Service tonight and tomorrow morning as how early showers (and upper-elevation snow) develop tomorrow afternoon is still a bit uncertain.  Meteorologists are not supposed to "wishcast," but I'm hoping it will be as late in the day as possible.

Despite the cold air, right now this doesn't look like a big snow producer for the mountains.  Below is the SREF plume for Alta-Collins, with the snowiest member generating just under six inches.  Some members produce under an inch.  Think dust on crust.