Wednesday, January 15, 2014

Utah Loses When Tug Hill Wins (and Vice Versa)

An interesting aspect of jet stream behavior is that when the western U.S. is under a ridge, the eastern U.S. is usually under a trough (and vice versa).  This is because the typical distance between long-wave ridges and troughs at jet stream level is about the distance across the contiguous U.S.

This means that if you are a powder hound, when Utah loses (meaning it is dry and under a ridge), the Tug Hill Plateau wins (meaning it is getting lake-effect and under a trough).  It's now always that clean cut, especially since lake-effect on the Tug Hill Plateau is strongly dependent on wind direction, but it does often work out that way.

Case in point is the forecast for Friday.  As shown in the dynamic tropopause (jet level) analysis below, Utah and the western U.S. are under the influence of a very high amplitude upper level ridge.  It is not yet time for western U.S. water resource managers to panic, but if this pattern continues to persist, the runoff this spring is going to be very very meager.

In contrast, an upper-level trough is moving across the eastern U.S.  The blast of cold air accompanying the trough will hopefully yield some lake effect for us to sample both with our instruments and with our skis.  I'm up early this morning for a quick ski tour on what the easterners like to call frozen granular, which is a nice way to say the snowpack is frozen rock solid.  Thus, we are looking forward to seeing the white stuff flying again.


  1. I think in California they are already starting to panic. The water situation does not look good for them at all.

  2. Friday ok, thanks for the heads up also responding to my other comment regarding Lake Effect.