We’re getting closer to the positive pattern change. We continue to wait out the retrogressive pattern that will slowy open up the storm door. Starting first with cold and light snow by Wednesday and next weekend, then progressing into bigger cold storms for week 2 around the 18th and into Christmas as the long wave pattern retrogrades opening the storm door.
Even though the system for Wednesday is pretty dry we could see some decent snowfall with the cold temperatures. Model output is around .25-.5 inches of liquid. At the base that should be a quick 3-6 inches but up above 7000 ft. in the colder air with higher snow:water ratios we could see 6-9 or even 9-12 above 8000 ft.
For next weekend there is some disagreement in how much moisture will be pulled in off the Pacific. Some forecast models would double down on the Wednesday storm but others show enough precip for 1-2 feet of fluffy powder.
I’m getting excited about the long-range forecast possibilities. As the ridge retrogrades back out towards 150w-160w latitude in the Pacific week 2 we could see some bigger storms that are plenty cold and could add feet of new snow before the Christmas holiday.
I have also been talking about how the blocking over the Arctic has been displacing and building some really cold air over Alaska and that will spread into Canada, then will start pushing South into the U.S. over the next few weeks.
We have plenty of teleconnection support with a -PNA pattern forecasted to continue. We look to continue into a triple crown of negatives with a -PNA, -NAO, -AO pattern. That pattern is rare and with this pattern we should see cold for the nation as well as coast to coast storms.
We saw a triple crown of negatives pattern back in 78/79 which was a 105% of average snowfall season. The MJO is also forecasted to become more active and in a neutral Nino season like this its affects can be much greater on the pattern. The forecast is strengthening into phase 1 then progressing into phases 2 & 3. What does that look like in December? Cold and Snowy! BA