Wednesday, February 1, 2017

A Thinning Cold Pool

Regime change is needed and we got a hint of it last night.

The sounding below is from yesterday morning and it shows a deep valley cold pool extending to about 830 mb (1700 m above sea level), capped by a strong inversion.

Yesterday and overnight, we've seen some shallowing of the cold pool and lowering of the inversion, which this morning was based at just below 850 mb (1500 m above sea level).

This has led to much higher temperatures at some bench locations than observed for several days.  For example, at our mountain meteorology lab on upper campus, we're now sitting at about 40ºF.  Doesn't it feel good? 

The air on campus remains polluted and PM2.5 concentrations remain at unhealthy levels (>55 ug/m3 at present), but they are lower than they were at this time yesterday.  

And, its rare that I feel a ping of jealousy about BYU, but they have rocketed to 50ºF this afternoon.  

Despite these improvements on the benches, a shallow layer of cold, gunky air remains in place on the valley floor and over the Great Salt Lake and Utah Lake.  I would not be surprised if we saw that cold airmass push onto campus this afternoon.  

I'm a bit unsure how this event will evolve over the next couple of days as some weak systems move through the state.  I suspect the cold pool over the Great Salt Lake and lower valley will be very difficult to crack, but I'll be getting up each morning and hoping for a pleasant surprise mix out, at least for the upper benches and hopefully the valley floor, just like you.  


  1. Any thoughts on the possibility of freezing rain with these weak systems, given the strong inversions and very warm (50F) air above valley floor?

    1. Sorry, but no. That requires a very careful analysis of the models that I simply haven't done and I would rather not comment than share an educated guess.

    2. ...but if I do such an analysis, I'd probably write about it. I just never know what I'll do each day. Much depends on whatever pops into my mind.

  2. I am unsure how to read these graphs. Even just a legends as to what the different lines represent would be helpful.

    1. I've tried to write up a post on how to interpret those graphs (known as skew-ts) and it's very difficult. Here's a better option. Goto You'll need to sign up for an account, but they are free. Complete the Skew-T mastery module.