A Disappointing Storm

Yesterday it was Utah 40 Arizona 39 and GFS 1 RRFS/HRRR 0.  

All and all the Friday Night/Saturday storm ended up at the low end of projections coming in with only 0.51" of water and 5" of snow at Alta-Collins.  So, based on the models available early Friday morning and used in the prior post, the GFS turned out to have the best forecast for this one, although its 0.6" of water and 6.5" snow was still just a bit more than observed. 

The frontal precipitation was handled well.  The real problem for the higher resolution models (HRRR and RRFS) was the precipitation Friday evening and the first part of the overnight period, which never materialized.   Additionally, there was some post-frontal instability for a while, but it was shallow with weak flow, so precipitation after frontal passage never got going over the higher terrain. 

In the end, radar estimated precipitation was showed little enhancement over the highest terrain with the most precipitation along the east bench.  

MRMS radar-estimated precipitation from 0000 UTC 14 Nov – 0000 UTC 15 Nov 2026

This was roughly in line with gauge data which showed 0.7 to 0.79" on the east bench near the mouths of the Cottonwoods, .84 and .88" in the lower canyons, 0.51" at Alta-Collins, and 0.6" at the Snowbird Snotel.  The Atwater SNOTEL reported 0.70".   Ignore some of the lower numbers in LCC as those appear inaccurate. 

Gauge reported precipitation from 0000 UTC 14 Nov – 0000 UTC 15 Nov 2026

So this was a storm in which the GFS perhaps benefited from having poor terrain representation.  

Over the years, it does seem like the higher resolution operational models have a difficult time identifying storms in which orographic enhancement is limited.  It is common for such enhancement to be more limited during frontal passages, so perhaps the case yesterday was that they overdid it during the pre-frontal period.  That said, there are times when the underdo the enhancement, such as during northwesterly post-frontal flow.  

We still have work to do.  

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