Storm Cycle Update

 Pretty good round of snow or should I say graupel overnight and this morning.  Accumulations in the mountains vary substantially and I'm not sure if Alta wiped their interval stake this morning or not as it looks like 4" on it, but the total snow depth is up 5 to 6 inches and the resort is reporting 8" as of 10 AM so I'll go with that.  

Gauge measured water total is about 1.2".  I'm hearing rumors that's high, but anyway you cut it, it appears to be a high-density graupelfest up there.  Sounds like a good day of skiing in my book.

Forecasts are still on for a colder storm tomorrow that will bring the Greatest Snow on Earth to both the mountains and the valleys.  Timing varies, with the HRRR bringing in a commuter special and the GFS a bit slower.  Strongly recommend that you check forecasts later today if you are commuting in the morning.  Quoting this morning's 5:23 AM issued Area Forecast Discussion from the NWS: 

"Locally higher snow rates will come with the front. Precise timing is lower confidence, with models ranging from roughly 5-11 a.m. for it to track through Salt Lake City. This will be capable of affecting valley travel Wednesday for some commutes, depending on timing."

I have more good news.  I am leaving for Austria on the 24th.  The models are already going for the Steenburgh effect to kick in, meaning snow when I'm out of town.  The Utah Snow Ensemble shows a break in a couple of days, but then things picking up again on the 24th.  

Coincidence?  I think not.  

Winter is Coming

I've been waiting all season to say that, but the models are trending and trending in a way that it may actually snow, not only in the mountains, but even, dare I say it, at low elevations. 

Let's break things down into pieces.  I'll use the Euro and hit some of the highlights.  Overnight tonight, a strong mid-level cold front pushes through northern Utah, bringing our first round of precipitation in the form of mountain snow and valley rain.  This front is the band of heavy precipitation extending from SW Wyoming through central Utah and Arizona in the Euro forecast below valid 0900 UTC (0200 MST) tonight.  

In the way of that front, moist, unstable southwesterly flow predominates late tonight, tomorrow, and tomorrow night with periods of mountain snow and snow levels near the valley floor, although official NWS forecasts are for less than an inch through Tuesday night at the lowest elevations of the Salt Lake Valley and a bit more on the benches.  

Wednesday looks like the best storm of the season for the valleys (something else I've wanted to say for a while, although we've had all of 0.1" at the airport so far!).  The Euro (and other models) has a cold front moving through Wednesday morning bringing snow to all elevations.  

I've been busy planning for our field campaign today so lack the time for a proper deep dive on snowfall amounts.  I encourage you to look monitor official forecasts and drive slowly on snow covered roads when they finally appear.  

Next Week Looks Active

This post is dedicated to friend and long-time Wasatch Weather Weenies reader Kevin Moore who passed away yesterday after a multiyear battle with pancreatic cancer.   Kevin was a devoted husband and father, avid biker and skier, and lover of life.  He set an example of how to live life to the fullest when facing the greatest of challenges and uncertainties.  

Beautiful Radar Data of Today's Storm

We're operating radars and collecting sounding's of today's storm as part of the SNOWSCAPE2026 field campaign.  The data coming in from the Huntsville radar is spectacular.  Below is what is known as an RHI (Range-Height Indicator) scan, which involves rotating the dish vertically rather than horizontally to take a vertical slide through the storm.  This RHI essentially represents a vertical cross section taken toward the WSW from the Hunstville radar (bottom left) across Snowbasin, and eventually over the Great Salt Lake lowlands upstream.  

The radar can't see through mountains, which show up  below as pink and white color fill due to their high "reflectivity".  I've highlighted Snowbasin where the terrain slopes up from about 1.5 to 2.75 km in heght.  

Evident in the RHI are four generating cells that extend to near or above 5 km above sea level.  These are moving across Snowbasin and then downstream into the Ogden Valley where they are producing rain and at times some graupel.  

We're getting some great data today of small scale convective cells interacting with the northern Wasatch.  

Another Warm Storm

Clouds and precipitation are back in the forecast, but unfortunately it's yet another warm event.  

Below is the ECMWF HRES forecast for 1800 UTC 11 Feb (1100 MST Wednesday).  A weak, decaying atmospheric river extends across the northern Baja Peninsula and up the lower Colorado River Basin.  Elevated (but atmospheric river level) integrated vapor transport extends into northern Utah with south-southwesterly flow at 700-mb.  The 700-mb temperatures at that time are forecast to be about -3.5°C, which would likely a snow level near or just above the base of Park City (7000 ft).  

A look at the HRRR-derived guidance for upper Little Cottonwood shows some dribs and drabs today, but periods of precipitation overnight, tomorrow, and tomorrow night totaling a bit over an inch of water and just under 10 inches of high-density snow through 5 AM Thursday at Alta-Collins.  The middle-left panel shows the wet-bulb zero height and our estimated melting layer in green.  The wet-bulb zero makes it up to the base of Alta, which means snow levels likely pushing 7500 feet or so before lowering Wednesday night (and lowering further on Thursday).

A look at the RRFS ensemble shows  four of the members very close to an inch of water and in the 10-15" range for snow through 11 AM Thursday (18Z 12 Feb).  One member is more excited.  Root for that one. 

So the good news is snow for the upper elevations.  It should help a good bit with ski conditions as we've had 3.5" of snow at Alta since January 8.  However, low elevations will suffer once again.  Mid elevations near 7000 feet will probably see a net gain through Thursday, but possibly with some rain on Wednesday.

It is what it is.

Below Median Westwide

Pretty dismal snowpack numbers westwide now.  Not a single basin has an above median snowpack as of February 4.  Missing on that plot due to the late arrival of California snowpack data is a basin in the south Sierra, but that was below median too as of February 3.   

Source: NRCS

In the Wasatch, many sites are at their lowest levels since the start of the SNOTEL record, in some cases extending back more than 40 years.  Every site is below the 25th percentile, meaning they are all in the lower quarter of prior snowpack water equivalent on this date.  

There will be no Steenburgh winter this year.