Tuesday, February 15, 2011

Records May Fall, But Not in Vernal

The maximum temperature record of 58F may fall at KSLC today.  The 1200 UTC sounding shows a 700-mb temperature of 0C, which if we can fully mix out, would yield a temperature of 63F.

At issue is the low-level cold pool, which is a bit deeper and stronger than observed yesterday morning.  I'm a bit perplexed as to why it is so strong and deep given the well-mixed conditions that were present yesterday afternoon.  It could put the brakes on the temperature rise today, but given the strong southerly flow, I believe we'll take a run at 60F today at KSLC.

Meanwhile, further to the east, the Uinta Basin remains mired in a miserable inversion.  Single digit minimum temperatures prevailed over the basin this morning from Duschesne to Vernal.  BRRRRR.

A 7-day meteogram from Vernal shows a gradual warming trend, but also that temperatures have not cracked 25F while we've been walking around in spring jackets along the Wasatch Front.  

The dynamics and evolution of these Uinta Basin cold pools has not been carefully investigated.  They appear to be far stingier than those along the Wasatch Front, and far less vulnerable to scouring during large-scale southwesterly flow.  Is this because Uinta Basin cold pools are stronger and deeper given the more direct penetration of arctic air into the region, or because the basin is more protected from southwesterly flow by the nearly continuous topographic barrier to the south and west?


  1. I have been fascinated by the Uinta Basin cold pool for quite a while. What I have noticed is that these types of cold pools tend to respond strongly to the near-surface pressure gradient. So in a warm sector situation (where the surface gradient is usually oriented SE-NW), the cold pools tend to migrate to the north and northwest sides of the larger basins. This is true of the greater Salt Lake Basin as well, and since the Salt Lake Valley is in the southeast side of this larger basin (and wide open to the north), we tend to mix out quickly. It seems that during these southerly flow situations, the terrain on the northern side of a basin tends to be the primary factor affecting the depth and resilience of the cold pool.

  2. Interesting thoughts. I'm going to have to watch these events a bit more carefully.