Following up on this morning's post, I thought I'd show that the HRRR is doing quite well for this event. Below is the "analysis" for 2035 UTC (0235 PM MDT). I've added a blue line showing a somewhat convoluted leading edge to the southerlies (note that I've ignored mountaintop obs for this analysis). The southerlies have entered the southern portion of the Dugway Proving Grounds, have met the Great Salt Lake Breeze in the northern Tooele Valley, and have penetrated into the western Salt Lake Valley. Note that the flow in the eastern Valley is either light southerly, easterly, or northwesterly.
The HRRR image I have from this morning's forecast is technically for 2130 UTC (55 min later), but still is a remarkably good forecast, especially with regards to the strong southerlies pushing northward into the Tooele Valley and western Salt Lake Valley.
The one quibble one might mike is that the surge of southerlies might have been a bit slow compared to observed (note that the observed southerlies have penetrated a bit farther north than forecast for about an hour from now). Nevertheless, this is a good harbinger for the future of numerical weather prediction.