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.  

If You Are Dreaming of Snow...

Snow crystal photographer extraordinaire Doug Wewer will be giving two talks on snowflake photography in the coming weeks.  One is this weekend at Powder Mountain (free).  The other is in late March at Alta ($5):

• Sunday, February 8th, 3pm-4pm at Powder Mountain’s Timberline Lodge.  Address: 6624 N Powder Mountain Rd, Eden, UT 84310.  Free. Info at https://powdermountain.com/events/passholder-weekend-1. 

• Wednesday, March 25th, 6pm-8pm at Our Lady of the Snows Center.  Address: 10185 E Hwy 210, Alta, UT 84092.  $5/person. Tickets and Info:  https://events.humanitix.com/snowflake-hunting.

You can check out Doug's photos at https://desertsnowphotography.com/. 

Will the Storm Track Finally Make an Appearance?

Our run of dry weather looks to continue through this coming weekend.  Since January 9, Alta Ski Area has recorded only 2.5 inches of snow.  If we make through Sunday, February 8 without any more snow, that will be 2.5 inches in a month (31 days).  

The models are showing some signs of life next week.  The Euro, for example, has a cold front moving into northern Utah Monday night and Tuesday. 

That's still a ways away so I'm not betting the farm on it, but a look at the Utah Snow Ensemble shows some signs of life in a number of the members.  

If you are a glass half-full type, half the members produce 1.02" of water and 14" of snow by 11 PM Wednesday 11 February  If you are a glass half-empty type, half themembers produce less than that.  More than 90% of the members produce more than 2.5" of snow, so there's a better than 90% chance that we will better what we got over the past month!  So exciting!

But for now and through the weekend, it's God bless the groomers.

Foggy Great Salt Lake and Environs

In the wake of yesterday's epic storm, which produced a 2" at Alta-Collins, the biggest storm since Jan 7–8 and what qualifies for all intents and purposes as a deep-powder day, fog and low clouds have filled the lower elevations of the Great Salt Lake Basin and Cache Valley.  It was a cool scene this morning with fog behind downtown and in some cases fingering around the skyscrapers.

GOES true-color satellite imagery for 1946 UTC (1246 MST) shows fog or low clouds covering the Great Salt Lake and surrounding playa, extending up through lowland areas and the Cache Valley to southeast Idaho.  

Forecasting fog and low clouds sucks and I'm not good at it.  With the ridge building in, I wonder if it could linger for several days, possibly spreading in coverage, or if it might break up.  I also wonder if it could spread down into the Salt Lake Valley this afternoon as the lake breeze and up-valley flow advects it southward.  That's really a battle between the transport of cool, cloud filled air over the lake and daytime surface heating which is trying to warm that layer and mix it vertically with drier air aloft.  

Time will tell. 

Speaking of the Great Salt Lake, the forecasts continue to suck (that's a scientific term).  Each week that goes by now without major storms is digging a deeper hole in the snowpack deficit for the spring runoff, making recovery less likely.  

Waiting for Snow, Still

Not much change on the weather front.  A weak system will come through tomorrow afternoon and evening.  Some models generate squat.  Others an inch or two.  A game changer it ain't.

A look at last nights Utah snow ensemble shows that storm around 00z 29 Jan with a few of the members producing modest accumulation but the vast majority at 2" or less.  A few ensemble members call for something around 00Z 3 Feb, but most are producing paltry amounts.  

It's only one model forecast, but the ECMWF HRES from this morning has a dreaded Rex block (high pressure "over" low pressure) along the west coast later next week.  

Hope something slips through the net or that the model guidance is just out to lunch.  Even a few inches would be nice.