Welcome to Mordor

Wind and warmth continue to dominate the weather here in Mordor, with the fires of Mt. Doom casting their glow over the Wasatch this morning.  

The average temperature since November 1 at the Salt Lake City International Airport of 46.3°F is a remarkable 2.4°F higher than any prior November 1 – December 21 period (note: the graph below includes data from the downtown weather bureau office prior to 1928).  

For the first 3 weeks of December (i.e., December 1–21) the mean temperature (43.3°F) is also the highest on record, although the gap to #2 (42.6°F in 1889) is not as large.  

Frodo and Samwise Gamgee continue to their quest to destroy the One Ring and break Sauron's evil grip on the weather of Utah, but remain well short of their goal.  

Hopes for the cover of precipitation increase around 0000 UTC 25 December (5 PM MST Christmas Eve) as southerly flow and an atmospheric river penetrate inland into Utah in advance of the very persistent upper-level trough that has been hanging off the west coast the past few days.  

The 82 members of the Utah Snow Ensemble have various ideas on the timing and intensity of the various bits and pieces of the storm, including the structure of the trough has it moves through Utah, but for the 3-day period from 0000 UTC 25 December to 0000 UTC 28 December (red-box below), 77 of the 82 members are producing 1–2.5" of water equivalent at Alta-Collins and 74 of the 82 members are producing 10–22" of snowfall.  

Most members are also calling for a cooling trend during that 3-day period, although it should be noted that at the start (i.e., 0000 UTC 25 December), median wet-bulb 0.5°C levels, which roughly denote the top of the melting layer, are at 10,000 feet.  This is a storm cycle that is going to start out very warm, perhaps with rain at the base of Park City on the evening of Christmas Eve.  By Christmas morning perhaps snow levels will be down to the base, but that's a touch-and-go forecast right now.  Monitor forecasts for this 3-day period if you are interested in details.  

Whether or not this modest storm cycle will enable Frodo and Samwise to reach Mt. Doom, destroy the ring, and loosen Sauron's grip on Utah weather remains unclear.