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.