Canyon Winds

The spring of crappy weather continues, at least along the east bench today.  The "canyon winds" are howling today from Ogden to Mill Creek.  Near Ogden, Hill Field is presently seeing peak gusts of 43 mph, but earlier, at about midnight, they hit 52 mph.

MesoWest surface plot at 15:21 UTC 15 May.
Peak gusts in mph annotated.

Further to the south, we're looking at gusts of 30 mph at the University of Utah and 32 mph near the mouth of Parley's canyon.  Note as well the easterly flow observed at Summit Park just to the south near Murdock Peak.

MesoWest surface plot at 15:21 UTC 15 May.
Peak gusts in mph annotated.

We presently have a situation with high pressure east of the continental divide and low pressure over the interior Pacific Northwest.  This has setup a large-scale pressure gradient and easterly flow that extends along and around the continental divide from Montana to southeast Wyoming.  It is this large-scale pressure gradient and easterly flow that are driving today's canyon wind event.

This morning's (1200 UTC) KSLC sounding features a stable layer between 800 and 750 mb.  Collocated with this stable layer is strong vertical shear and winds that veer from SSE to S.  I suspect this stable layer reflects the top of the cooler air that is spilling across the Wasatch Crest and into the Wasatch Front.

Source: NCAR/RAL

Unfortunately, KSLC is typically downwind of the strongest easterlies, so soundings from this location are of limited value for understanding these events.  Ideally, it would be nice to have data over and east of the Wasatch Mountains.  The closest upstream site is Riverton, WY, which is quite a ways a way, but does show that the "upstream" airmass is a shallow layer of cold air that is surmounted by a strong stable layer at 700 mb.

Source: NCAR/RAL

So, we have a shallow layer of cold air driven across the Wasatch Crest by the large-scale pressure gradient and related easterly flow.  This is occurring not just near the canyon mouths, but pretty much along most of the Wasatch Front from Mill Creek north.