We have been teasing about another round of heavy snowfall around the Superbowl, and I’m here to dive in a bit more.
Basically, a series of waves is forecast to break over the western US. These waves will dump plenty of precipitation and usher in a cold air mass in their wake. The complexities of this event are a bit clearer in 500 millibar simulations. These seem to reveal two mid-level troughs that push out a ridge, which is now sitting to our west.
We’re often about half a storm cycle behind the eastern US, and I think this weekend’s storms are the seesaw response to an arctic front that has just hit New England.
Going to the toilet this morning in north-northeast US this morning … Photo: Colin Lovequist via Conexao Geoclima pic.twitter.com/T3weTFzFtP
— severe-weather.EU (@severeweatherEU) January 30, 2019
The First Wave
Part one begins with precipitation Saturday morning during a period of incoming warm and moist air from the subtropics. The air cools down a bit once precip occurs, and the freezing level lowers to about 7500 feet. This, of course, means plenty of rain in the mountains at lower elevations. Rain reaches the valley floor sometime later in the day Saturday.
Higher up expect a half-foot of snow at least (most ski resorts) through Sunday afternoon. Resort winners will be at higher elevations (e.g., Cottonwoods) and those that favor southwesterly flow (e.g., Powder Mtn). These resorts could easily see a foot or more before the Superbowl.
Check back tomorrow and Friday for a tighter forecast; during this first storm, the temperature and moisture profiles aren’t nailed down and can make a substantial difference in snowfall accumulations. Also uncertain is the avalanche risk—look for that forecast before Saturday.
The heaviest precipitation should occur early Sunday. Around the same time, freezing levels dive quickly down to the lowest elevations. Snowfall amounts for valley folks is a bit uncertain because the models aren’t sure how the storm’s heaviest precipitation will coincide with its coldest temperatures.
The Second Wave
Five days out, part two is colder and considerably more uncertain than the first. You can expect this second storm to hit Monday night or Tuesday with similar strength as the first storm. We’ll have a more detailed snowfall forecast for part two by halftime Sunday.
Enjoy the snow!