Monday, November 29, 2010

Orographic precipitation enhancement, interrupted

Yesterday's storm is now in the record books and it was an impressive one.  It's been quite a while since I can remember this much snow in my yard.  Perhaps the last time was Thanksgiving 2001 after the famed 100 inch storm (named for snowfall at Alta, although the valley got pounded too).

Storm-total snowfalls reported on the NWS web site for locations in the Salt Lake and Tooele Valleys:

And in the Wasatch Mountain south of I-80:

Bottom line: There is remarkably little difference between the lowland and mountain snowfall in this case, as discussed in an earlier post.  Even overnight, when I thought we'd see more orographic precipitation enhancement, there was little.  This case provides a great example of why the use of a climatological precipitation-elevation relationship to downscale or redistribute coarse-resolution numerical guidance can be dangerous.  At issue is whether or not one could reliably anticipate a similar event in the future.  

1 comment:

  1. There was also a Christmas week event maybe in December 2003 that dropped a lot of snow. I remember perhaps 2x as much on the ground in the yard with that event. My recollection is that the pattern was one where the lake was a significant player as numerous waves rotated through a slow moving trough.