Wednesday – Tuesday Forecast:
The mostly sunny days and mild temperatures will continue through Thanksgiving. Then over the weekend, the pattern shifts with the ridge backing up to near the West Coast, and a cold trough digs south into the Rockies & Central U.S.
Earlier this week, the models suggested that part of that trough and colder air backed southwestward into CA. The trend over the last few days has had the high-pressure ridge near the coast farther inland, and the trough farther east through Tuesday.
We still expect temperatures to cool a little, but highs will only go from the 50s down to the 40s, instead of the 30s, and overnight lows may only go into the 30s instead of the 20s. It may get cold enough to make a little snow, but it’s not the optimal setup for making a lot of snow at night, and it may be too warm for some parts of the mountain.
Possible Cold Shot:
The ridge near the coast is forecast to back NW a bit again by next Wednesday, the 3rd, and we will take another shot at trying to back the cold trough farther west into CA. This is a similar setup to what the forecast models were showing for this upcoming weekend, which trended towards the trough staying east. That trend is starting for next week as well.
If the trough is able to dig far enough West, we should see a shot of colder air, at least for a day, and a chance for some snow showers with the front. We may also stay dry through Wednesday, and if so, likely through at least Friday the 5th.
Long-Range Outlook:
The GFS & European ensemble mean models continue to show the pattern shifting during the 1st weekend of December into the week of the 8th, with the ridge near the West Coast shifting NW away from the coast and a trough over the West Coast.
That would, in theory, open the storm door if the ridge stays far enough west and storms have time to spin up off the coast and track south into CA. They still show near to above average precipitation between the 6th – 11th as well.
But the red flags are still there. We need a -PNA/+EPO combo pattern to really open up the door. Some models are trending away a bit from both. There is also still retraction of the East Asian jet stream, but not quite as much as earlier this week on the models.
The model that is scaring me is the European AI ensemble model, which has been the first to show the ridges closer to the coast all month, and has ended up being the most right in the end. It shows the center of the ridge is farther south and closer to the West Coast, which could be a drier pattern than the other models.
The good news is that most of the operational and ensemble mean models are still showing precipitation chances increasing beyond the 5th. Let’s hope they are right. A lot can change in 10 days.
BA
