Sunday, May 5, 2024

A BIG MAY STORM

This is a blog post that deserves all caps.  The models continue to advertise a major May storm cycle that will bring substantial snowfall to the mountains of northern Utah. 

As I write this on Sunday morning, the south winds are blowing and temperatures in the Salt Lake Valley are in the 60s.  

But everything is about to change.  A look at the latest observations shows northwesterly flow and colder air to our west.  Along I-80 at at Knolls it's 43°F.  

The front will likely push through the Salt Lake Valley from about 9–11 AM this morning.  Precipitation will also spread across the area.  The coldest of the cold air arrives tonight.  The GFS shows unstable, northwesterly flow tomorrow morning with 700-mb tempeatures around -8°C.  In January, that would probably mean wet snow on the valley floor.  In May, it's probably down to near bench level.  Don't be surprised to see flakes late today or tomorrow.  


For the mountains, the models are putting out some big numbers.  The 6Z HRRR forecasts 19" of snow for Alta through 0600 UTC (0000 MDT) Tuesday.  


The GFS is locked in with similar numbers through that time.  Additionally, it keeps us in a cold pattern through Wednesday with a series of systems moving through and pushing the storm totals to about 3" of water and 40" of snow by Wednesday.  


These are serious May numbers.  I'll add that the forecast above also shows northwest winds on Monday on Mt. Baldy of over 40 mph.  Real winter, with real-winter avalanche conditions, and the possibility of a rapid change to wet-snow avalanches conditions should the sun appear.  

Let's be careful out there.

3 comments:

  1. 24 hour 42 degree drop at KSLC, from 78 yesterday (5/4) at 4pm to 36 today (5/5) at 4 pm. That's a strong cold front, and pushing the 24 hour record temp decline at KSLC. Do you know of an occurrence where 24 hour decline was more than 42 degrees? Of course it warmed up to 37 degrees once it stopped snowing and the 5pm temp yesterday cooled to 76, so 39 degree drop from 5pm to 5pm. Impressive decline

    ReplyDelete
  2. I’d be curious to see an analysis of where cold air sourced from. Seeing -12 700 in the GFS for Tuesday AM which feels insane for May. Was there a strong, deep arctic pull with this low?

    ReplyDelete
  3. Do you have any sense for how rare of a snow event this is for this time of year for the low elevations? A friend at 5600' in Emigration currently has over a foot of snow on the ground, and it isn't over.

    ReplyDelete