Wednesday, November 11, 2015

Lake Effect Reflections

Last night we got a bit of love from the Great Salt Lake, with the storm evolution exhibiting a number of key characteristics of lake-effect systems.  My apologies for color aliasing problems, but I couldn't correct them in the time I had available.

The action started over Tooele County and the Oquirrh Mountains and then spread eastward to the Salt Lake Valley and Wasatch range.  There are two major flavors of lake effect generated by the Great Salt Lake, banded and non-banded and you can see both in the loop above.  The band is a weak one, but affects the Oquirrhs and the western Salt Lake Valley.  The non-banded precipitation is further east.  Note the disorganized nature of the echo cells over the eastern Salt Lake Valley and the Wasatch Range.

The Oquirrhs actually receive quite a bit of lake effect, as much as upper Little Cottonwood Canyon and, because they receive less precipitation from other storms, lake-effect contributes a greater fraction of their cool-season snowfall (about 8%).

Forecasts of lake effect are notoriously tricky.  Although we've improved a lot in anticipating when lake-effect is possible, specifics on location and amount remain very challenging.  We have a paper that just came out in which we simulated 13 past events over the Great Salt Lake using a next generation, high-resolution forecast model with 1.33 km grid spacing and found the model skill to be about the equivalent of what we find for summertime thunderstorms.  In addition, the model frequently produced intense lake-effect bands during situations when only non-banded lake-effect was observed.

We still have a lot of work to do in this area!


  1. Here in Taylorsville there was about 0.07" of water equivalent from that lake band, basically all of it in the form of small graupel.

  2. Just as an FYI, I am typically putting this type of info in my CoCoRahs site notes (UT-SL-96) when I have it, in case anyone has an interest in it for whatever reason.