Thursday, March 5, 2020

Spring Has Sprung

Yesterday's (Wednesday) high of 60˚F was the third 60 degree day of the calendar year, tying Feb 28 and 29 for the warmest temperature of the year so far. 

We will eclipse that today, with the NWS going for a high at the airport of 63˚F.  I'm planning to go for a sloppy and slow skate ski at Mountain Dell later today as the skiing there is now officially on life support and probably won't last much longer. 

The forecast over the next several days suggests continuation of a spring-like pattern, although precipitation will be moving in over the weekend. 

Mild conditions will prevail through Saturday.  Today will be bluebird and spectacular.  Tomorrow (Friday) will also be nice, although there may be some inconsequential wispy high clouds at times and moderate southerly flow at upper elevations. 

Saturday is a clear transition day with periods of high clouds and strong southwesterly flow in advance of an approaching trough and cold front, as depicted below in the GFS. 

This is the type of pattern that can result in significant snowpack sublimation.  It will be interesting to see if we see a small decrease in snowpack water equivalent at some of the SNOTEL sites.  It might also be a bit early for this to happen, but blowing dust is a possibility if emission sources in southern and western Utah are ready to be active. 

Although the approach of a front is sometimes cause for excitement, in this case, the system sort of peters out and we get just some remnants with no real wind shift to northwesterly at crest level.  We then see a period of southwesterly flow with dribs and drabs, before a closed low finally decides to move inland toward the middle of next week.  To try and summarize this mess, below is the GFS 500-mb and 3-h precipitation forecast from 1200 UTC (5 AM MST) Saturday 7 March through 1200 UTC (0600 AM MDT) Wednesday 11 March.

The entire period is relatively mild (although not as warm as today), so precipitation will most likely be in the form of rain on the valley floor.  In the mountains, NAEFS forecasts show dribs and drabs of snow for upper Little Cottonwood.  The ensemble mean for the entire period through 0000 UTC 12 March (6 PM MDT Wednesday) is around 15 inches, although this is skewed by a small number of big outliers.  My view is that we get a few inches here or there and that the most likely total for the entire period is in the 6-15 inch range. 

Given my philosophy that low expectations are key to a happy life, I prefer to go into a situation like this thinking that we're not going to get a lot of snow and hoping that we end up on the upper-end of expectations. 


  1. SPC is mentioning a chance of thunderstorms this afternoon that could result in some strong wind gusts. Seems a bit unusual for this time of year, but I guess if it's going to be 70 degrees...

  2. Convective snow-eaters. A lot of sublimation and melting, even without rain.