An unusual but very good weather pattern is looking to set up over the western US that could bring rather continuous active weather from California to Colorado to Montana to British Columbia and all points in between starting Thursday and possibly lasting through the new year. This pattern will pretty much guarantee that mountain locations will have a White Christmas or least have snow falling on Christmas day and will expect much more through the new year.
An Aleutian High will be building and maintaining its strength for quite some time. A similar type of pattern was seen this summer when a blocking ridge was set up over the Western US keeping Colorado warm and dry and allowing for all storms to pass by and not impact us. Well, this go around, the blocking ridge is far to our west and north and that will allow for all of the storms to travel towards our area and if the models are correct, this could be the pattern for the next one to two weeks. Or more.
This type of weather pattern is something that could be a game changer for the western water woes. A continuous stream of active weather means that nearly consistent snow (and moisture in general) is possible for the foreseeable future. On top of this, some Atmospheric River moisture is poised to impact the west and interior Rockies maybe more than once during this period leading to even bigger storm totals at times. Essentially, this pattern is shaping up to bring consistent snow to high elevations with pulses over heavier snow from time to time.
A broad look over the Western US shows that many basins are running below to well below average for snowpack. This storm, or series of storms, will like boost snowpack numbers across the west significantly in many areas. This could turn into a rather extreme pattern depending on the longevity of unstable weather. Definitely a rarity to have this widespread of snow for this amount of time nowadays. Before we jump into snowfall totals and details for different regions, this pattern is unusual and a break between storms may not even be realized for some areas because of the consistent nature of this setup. Most forecasts are calling for ski areas to get new snow every day for possibly more than 10 days straight.
FORECAST BY REGION
Snow will begin to fall across the PNW on Wednesday as low pressure moves south from Canada. Snow showers will continue at varying intensities each day through the upcoming weekend as a low pressure sits and spins overhead. Flow will be mainly southwest to westerly most days leading to west facing slopes getting slammed with snow but really, all mountains should do very well will this round of snow. From Mt. Bachelor ro Crystal Mountain to Mt. Baker, upwards of 3-5 feet of snow is completely possible here. Inland areas will receive a bit less but still commendable totals. Up to 30″ of snow may fall in inland areas, if not a bit more.
After Sunday, the unsettled weather continues and these same areas may double these totals by the time the New Year comes around. Overall some get snorkel weather and powder conditions will be abundant. At times, the snow may be a bit wet and sticky but as cold air settles in, the snow will turn more powdery.
California is going to do GREAT from this storm. The only inhibitor will be warm air which will be a concern initially. Snow levels will start rather high at this atmospheric river of moisture surges in from the tropics. Winds will be southwesterly and western during this time leading to consistent pacific moisture feeding in. As colder air sets in as the weekends gets going, we’ll see snow levels drop. Most ski areas of California bracing for feet of heavy, wet snow. This will definitely be a fun storm to chase but initially, the snow will probably be sticky but get fluffier as the weekend goes on.
After this weekend, the pattern looks to continue to be active with more snow and moisture getting pushed across the Sierra. Additional snow next week could double what we see through this weekend. Great news for California. Ski areas from Alta Sierra to Mammoth to the Tahoe area will be very happy with their end of the year present.
Inland areas of the Northern rockies will be under the influence of this large area of low pressure and with residual moisture reaching inland, snow totals will be very impressive especially near Sun Valley and Brundage where wind flow will be most efficient. Snow will begin Wednesday and continue through Sunday with varying intensities. Areas around Big Sky may not perform as well since they really need more of a northerly wind to get big totals. Jacson Hole could do very well with this setup.
Looking past this weekend, more snow if forecast for all these areas so more powder days can be expected before the New Year.
Utah and Colorado
Utah and Colorado will get some really fantastic snow from this event. Utah, getting slammed with southerly and westerly winds will get some leftover moisture from the atmospheric river and will get some gnarly surprises by the end of the weekend with over 30″ possible in some areas of the Wasatch.
Colorado will also be benefitting from the atmospheric river of moisture. Especially in the San Juans where 1-2 feet looks easy to accomplish by Sunday. As is normal with these atmospheric river events, snow levels will start a bit higher and drop as cold air settles in. Crested Butte, Wolf Creek and Purgatory could be a big winners by the weekend with over two feet of snow possible.
The pattern stays active even here for the week leading up to the new year so powder days will be aplenty for us holiday chasers.
Enjoy the fresh snow and the free refills that are going to be constantly flowing for the foreseeable future. We love this kind of forecast. This is not just good for chasing but also for snowpack. I just love watching the west get replenished and this is definitely a replenishing type of storm.