Let it Snow!

TL;DR:

    We are kicking the weekend off right with snowfall starting in the Wasatch early Friday morning and picking up speed around 11 am. A conveyor belt of shortwave troughs embedded in the larger-scale system will impact Northern Utah through Monday morning, bringing much-needed snowfall to our ski resorts. 

 

NOWCAST:

    Snowfall has already started in the central Wasatch and will pick up through the day. Temperatures at Alta-Collins are 15 F with winds out of the WNW at ridge levels. 

 

(Alta Mt Superior: https://www.alta.com/weather)

 

SHORT-TERM (24-48 hrs):

    Expect snowfall to continue all day today and Saturday as successive shortwave troughs barrel through Northern Utah. Snow totals for this storm are tricky as models show a large array of outcomes. For Alta, pessimistic models show ~20 inches while optimistic ones have 30+ inches falling through 5 am Sunday. Either way I’m not complaining. Results will most likely be somewhere around 25-35 inches. Expect less snowfall for Wasatch back resorts, anywhere from 20-30 inches. Winds at 9000 ft and 11000 ft ridges will be out of the West ~15 mph and ~20 mph respectively with wind gusts 5-15 mph higher. Winds will continue to strengthen as the system progresses. 

 

(Utah Weather Center: https://weather.utah.edu/. Graphic shows 500mb height contours and

Absolute Vorticity contour fill. The green lines highlight shortwave trough axes, and the blue arrow shows the direction of the system)

 

LONG-TERM (48+ hrs):

    The coldest temperatures will occur Friday night, which coincides with a high snow-to-liquid ratio (SLR) and less dense snowfall. Temperatures will then slightly rise through Monday, lowering the SLR and depositing more dense snow on top. We refer to this as an upside-down storm, which is a recipe for instability within our snowpack. The period of heaviest snowfall will likely begin Saturday night (6-8pm) and continue early into Sunday morning (~2 am). Snowfall will begin to lighten and stop sometime early Monday as a high-pressure ridge takes over the region. 

(Utah Weather Center: https://weather.utah.edu/. Figure shows the SLR at Alta (bottom right figure) being highest on Friday night (SLR~20) which coincides with the lowest temperatures (top left figure) and then dropping to a SLR of ~10 by Sunday. Blue circles highlight these regions and arrows show the trend)

 

Snowfall Forecast: (through Sunday 5 am) 

 

Alta/Bird: 25-35 inches

Brighton/Solitude: 22-32 inches

PC/Deer Valley: 20-30 inches  

 

Be careful if you are going into the backcountry and visit UAC for more information. #knowbeforeyougo