Thursday, February 22, 2018

When the Ridge Is in Its Happy Place

Over the past week and in forecasts for the next 10 days the overall pattern remains in some ways similar to what we have seen all winter.  The flow is very high amplitude, with strong upper-level ridges and troughs.  This can be seen in the dynamic tropopause analysis below, which is essentially a map of jet stream level winds with areas of locally low tropopause pressure (warm colors) indicating ridges and areas of locally high tropopause pressure (cool colors) indicating troughs. 

What has changed, however, is that the mean ridge position has shifted upstream to what I'll call its "happy place" over the central Pacific Ocean.  As a result, we will see several amplifying upper-level troughs digging into the western U.S. over the next 10 days.  This is a much colder pattern than we have seen all winter.

It is also a more "active" pattern.  Forecasts for the next 7 days show a series of weak but frequent storm systems moving through.  Total accumulated water equivalent produced by our downscaled NAEFS product for Alta ranges from 1 to 3 inches of water.  The former would be a bit below average, the latter almost double. 

Thus, beginning with last week, this looks to be the best stretch of winter weather we have had all season.  Anything close to average beats the previous 3 months. 

The Steenburgh Effect is in full force. 


  1. Jim: The Steenburgh Effect allowed me to indulge in the 18" storm last thursday (when only in town for 1.5 days) & seems to be optimizing conditions for our upcoming week in the Wasatch starting March 1. We thank you for that (and your blog in general, as this family of amateur meteorologists is constantly educated in your space). Good luck with the hand (well, we assume it won't be fully healed until at least March 8 :)).

  2. I have an east coast effect that I'm bringing to Utah a week from today and that ensures more snow. I'll be skiing the singles line because my wife has a torn peroneal tendon so shes on the DL and we'll be there watching from the lounge. Last time she was on the DL it worked.

  3. oops should proof read.............she'll be watching, I'll be skiing:)