What Is That?

A rare weather phenomenon known as a cold front will be passing through northern Utah tomorrow night.  Be sure to get out and experience it first hand as cold frontal sightings are indeed quite rare these days.

Tomorrow looks to be an interesting day in the prefrontal environment as temperatures aloft remain quite mild and clouds and precipitation (valley rain, mountain snow above perhaps 7500 feet) drop into the state.  Looks like a good garbage-bag ski afternoon if you are headed to the mountains, especially if you are going to the northern Wasatch.  How quickly the inversion scours out is unclear, but assuming it goes, which I think is likely, we may see temperatures pop up into the upper 40s or near 50 in the Salt Lake Valley, which would be a wonderful change.  Keep your fingers crossed.

Tomorrow (Wednesday) night, the cold front pushes through and will be the death knell for any lingering remnants of the inversion (don't let the door hit you on the way out).  It will also bring more snow to the mountains.

How much snow you should expect depends on your model of choice.  The NAM is excited, going for 19 and 26 inches, respectively, at Alta in it's 12- and 4-km versions by 5 PM Thursday.  The GFS (pictured above) is somewhat less excited.  The gold standard EC is a bit slower on the front, but perhaps between the GFS and NAM on precip amounts.  A big issue for snowfall accumulations will be the temperatures, especially during the first part of the storm tomorrow afternoon and evening.  Accumulations will be limited below 8000 feet tomorrow afternoon and possibly evening before temperatures fall.   Above 8000 feet, this looks to be a decent base builder for the mountains, and while we normally like that in November, we will take it this year in January.