Powderchaser Luke here again for a special discussion on the incoming Winter Storm!
Less than a week ago we were posting about a big snowstorm to kick of the season for Arizona Snowbowl, and here we are again with yet another huge storm. This one has the potential to make last week's 22\ look like nothing. Most people dream of a white Christmas, but skiers and riders of the Arizona Snowbowl dreamt of a white Thanksgiving, and their dreams are coming true in a massive way! The storm is still 3 days away, so these totals will need to be refined, but right now we are expecting 2 to 3 FEET, with up to 4 FEET at the highest elevations! Yes, you heard that right. The storm will start early Thursday and last until Friday night, with cold temperatures and low density snow from Friday morning onward. Deep is understatement on this one.
The Storm
There are so many fascinating aspects to this storm, it's hard to know where to begin. Check out the forecast satellite imagery below. You can see our storm pinwheel off the CA/OR coast before moving inland.
(Image courtesy of Weatherbell)
This is a sign of rapid strengthening, and the result is a compact but powerful storm that will make landfall on the West coast packing wind gusts just shy of hurricane force. This storm is forecast to undergo bombogenesis, which occurs when a storm experiences the designated criteria of rapid intensification. We have another bomb cyclone on our hands. This is the beginning for our storm, as this intense low pressure comes ashore and the upper level low pressure system digs South, setting its sights on the Snowbowl. Below is one model output for snowfall for this event.
(Image courtesy of Weatherbell)
As you can see, once the snow starts falling on Thursday morning, it will continue, heavily at times, until late Friday or Saturday morning. This model, the American, shows well over 2 feet at the resort. However, this is assuming 10:1 snow to water ratios (1 inch of water equates to 10\" of snow) during the entire storm. While initially a 10:1 snow to liquid ratio may be reasonable, that will not be the case later in the storm, as the cold temperatures will cause this to climb to 15:1 or even higher at times. This storm will be right side up, with more dense snow initially followed by a large amount of low density snow on top. The perfect type of storm. In our last forecast we took a look at the NAEFS ensemble plumes. Let's do that again.Please refer to the last Arizona Snowbowl forecast for an explanation of this graph.
(Image courtesy of the University of Utah)
That is quite an impressive output, with several members showing more than 90 inches! There is also a very large spread, with 37/42 ensemble members between 30-80\", and a mean of 60\". We do think these tend to be overdone a little bit, but it does give you a good idea of both the potential with this storm as well as the uncertainty on just how much snow will fall.
There is a lot going on with this storm, but the cold air and ample moisture are key. Let's first look at the source of this moisture. For more details about how this storm is unfolding, visit our site and the previous posts on this storm. Check out the integrated water vapor transport image below.
(Image courtesy of CW3E)
There are two moisture feeds with this storm, and they will combine to provide copious amounts of water to the region. The reason for the second moisture tap is a second upper level low. You can see it on the image below. Eventually it will merge with the low to the North.
(Image courtesy of Weatherbell)
You can see the two upper level low pressure systems, with counterclockwise flow streaming Pacific moisture into the region. It's a beautiful sight to see. Lastly, let's take a look at the temperatures.
(Image courtesy of Weatherbell)
In this NAM (short range American model) forecast, the cold front has passed the Snowbowl overnight on Thursday, with 700mb (~10k feet) temperatures of about -10 C (14F). Any snow after that will be very low density. This is shaping up to be a memorable first week for the Arizona Snowbowl, and you can rest assured we will be there to enjoy it. Say hi to us in the lift line!
Until the next incredible Arizona Snowbowl snowstorm!!
PLEASE CONSIDER USING OUR CONCIERGE CUSTOM FORECASTING FOR THE UPCOMING SEASON: https://powderchasers.com/concierge
Powderchaser Luke
