Wasatch Weather Weenies

It's looking like the last week of February and the first two days of March will largely be snowfree in the central Wasatch.  We have a weak cold front moving through today, but it's a dry one.  If it wasn't for the wind and the lower temperatures this afternoon, you probably wouldn't have noticed it. The Utah Snow Ensemble is flatlined until 2 March when a couple plucky members produce a little snow.  Most hold off until 0000 UTC 3 March or later.  After that, the various ensemble members are throwing spaghetti on the wall.  Some do nothing, others up to 40" of snow.  The spread in the runs is pretty consistent from 0 to 40.  Your guess is as good as mine for what's going to happen.   The reason for that spread is the highly split flow forecast to pervade over the west.  The latest Euro forecast valid 0000 UTC Monday 3 March shows the pronounced split over the eastern Pacific with one branch of the jet moving northward through Canada an...

Our recent storm cycle has pushed the mountain snowpack to about as close to median as you can get in northern Utah.  Per the latest SNOTEL observations, northern Utah basins are sitting anywhere from 90 to 107% of median snowpack water equivalent.  Source: NRCS The situation becomes grimmer over central and southern Utah, but I have cut that off in the plot above because who wants bad news these days.  We should add a bit more to the northern Utah mountain snowpack over the next few days as we're in what I'll call a "scrappy" west to northwest flow through Tuesday, meaning the mountains will squeeze out a bit of snow from time to time, and then another storm system rolls in later in the week.  As is often the case, the US GEFS ensemble is a bit wetter than the European Ensemble (ENS), but through 0000 UTC 22 February (5 PM Friday), the middle 50% of the Utah Snow Ensemble is generating 1.04–1.66" of water and 14-24" of snow for Alta-Collins.  Spread is grea...

Forecasts remain very much on track with the expectations from a couple of days ago (see An Exciting Forecast ).  For the central Wasatch and Alta-Collins specifically, the models are calling for snowfall to being today in southwesterly flow ahead of the approaching trough and continuing for the most part through Saturday afternoon when we are in the colder, post-frontal storm phase.   I wouldn't be surprised to see a break or two in the snowfall at times in there, but totals look to be impressive.  Through 11 PM MST Saturday, the GFS is coming in with 1.90" of water and 24" of snow.  The HRRR doesn't go out that far, but just through 11 PM MST Friday it's at 2.4" of water and 24" of snow, so it's quite excited about the warmer part of the storm.   Most members of the 82-member Utah Snow Ensemble are in the 1.5–3" of water and 20–40" of snow range through 0600 UTC 16 Feb (11 PM MST Saturday).   This is also a statewide storm, not some local...

I'm pretty excited about the latest forecasts as it looks like we are going to see a bonafide frontal system moving through Utah, spreading the goods around statewide.   But before jumping ahead to the storm, it's worth talking about what is going to be happening today and tomorrow.  During the day today, a cold trough will be dropping down out of the northwest and through Utah.  It will generate a little snow, mainly in the mountains and drop temperatures at all elevations.  Below is the GFS forecast valid 0000 UTC 12 February (5 PM MST Tuesday) showing the cold northwesterly flow with 700-mb temperatures of as low as -20ºC grazing the Utah-Idaho border.  My 20/20 rule is something I use to remember what the outlier 700-mb temperatures are in Salt Lake City and the northern Wasatch.  Anything above 20°C is unusually warm or below -20°C is unusually cold.  As shown in the sounding climatology below, 20ºC has historically been an upper-limit for 70...

Yesterday evening's weak disturbance tried to get us to Steenburgh Winter this season, but alas, like the Rams in Super Bowl XXXIV, we came up just short.  The obs from Alta-Collins show 5 quick inches falling, bringing the total snow depth to 99" for three hours.   Close, but not close enough. The rules of Steenburgh Winter are quite clear and strictly enforced.  If the plane of the goal line is not broken, there is no touchdown.  If there is no 100" by Feb 10, there is no Steenburgh Winter.  

Hell of a storm yesterday in Little Cottonwood Canyon with copious amounts of graupel.  Observations from the Alta-Collins site showed a storm total of 19" of snow and 2.70" of water which fell over a period of 18 hours.  Water equivalent rates remained above 0.2" per hour from 9 AM to 3 PM, above 0.37" per hour from 11 AM to 2 PM, and peaked at 0.41" from 12 to 1 PM.  The frontal structure during this event was complex, but I'd say the heaviest precipitation period was prior to and possibly during the frontal passage.   Watching the radar, it appeared that the Alpine Ridge between Little Cottwonwood Canyon was the locus for heavy precipitation development and that is confirmed by the MRMS Radar only precipitation estimate below which showed an elongated area of more than 1.25" of water and a maximum of up to 1.50" from just west of the American Fork Twin above Snowbird to Sunset Peak just east of Alta.  Source: https://mrms.nssl.noaa.gov/qvs/prod...

Below is a transcript of the letter that I sent to Utah Senator John Curtis concerning the cuts being proposed for NOAA and the National Weather Service by President Trump and DOGE.  A slightly modified version was sent to Representative Blake Moore and submitted to the Salt Lake Tribune for consideration as Public Commentary.  If enacted, these cuts will put the safety of Utahn's at risk.  Media reports suggest that the cuts being considered are 30% to the budget and 50% to personnel. There is no private sector company today ready to take on the enormous responsibility of protecting life and property in Utah from high-impact weather and cuts to the National Weather Service will weaken their ability to provide critical decisions support services to emergency managers.  If you agree (or even if you disagree and want to share an alternative opinion), please consider writing your legislative leaders.  Dear Senator Curtis: I am a Professor of Atmospheric Scienc...

It's February 6th and the snow depth at Alta-Collins sits at 80 inches.   During the early days of this blog, way back in the epic 2010/11 season, when readership of the Wasatch Weather Weenies was much smaller, I jokingly (and narcissistically) declared the period from when Alta-Collins reaches 100" of snow depth to February 10th as being Steenburgh Winter (see Last Day of Steenburgh Winter ).  I still consider 2010/11 to be the gold standard here for ski touring. We hit 100" at Alta-Collins on December 20th and that was a year characterized by frequent goldilocks storms that just kept coming until Mid May.  Snowfall by the end of May at Alta Collins was about 800" (estimated since Alta stops measuring at the end of April), but unlike 2022/23, where the canyon was overwhelmed, access was not severely restricted.   The idea of Steenburgh Winter was to highlight what I call the crème de la crème of backcountry ski conditions.  The 100" mark is abo...

The Trump administration has been aggressively attacking America's science organizations and institutions since Inauguration Day, including the National Science Foundation, commonly referred to by scientists as "NSF."  They placed a freeze on funding actions for a while (since unfrozen at least temporarily by the courts), have program managers reviewing grants for keywords that suggest violation of possible executive orders , and now are threatening to layoff 25 to 50% of the NSF staff .   The importance of the NSF for US science, workforce development, and economic growth is enormous, but not always obvious.  When the military proposes to close a base, there's often a major uproar about how that will hurt the local economy.  If the NSF were severely restricted, there would be layoffs at universities across the country, including graduate students, post-docs, and staff.  There would also be long-term ripple effects on American innovation, national security...

Yesterday was a remarkable day at the Salt Lake City Airport with a minimum temperature of 56°F and a maximum temperature of 66°F.  Each of these is the warmest temperature observed so early in the calendar year, meaning they are both records for the period from 1 January through Feb 3. The minimum temperature of 56°F blew everything prior out of the water, eclipsing the prior record by a remarkable 7 degrees.  Curiously, many of the prior highest minimum were set in January in the early 1900s.  At that time, the NWS observing site was in downtown Salt Lake City.   Source: https://xmacis.rcc-acis.org/ But that 56°F is even more remarkable than that.  It is the highest minimum temperature observed on any day between 3 November and 17 March, tying 9 November 1927.  The 66 is not as much of a black swan, but still a very impressive maximum for early February.  And of course the warmth continues today.   Extending back into the weekend,...