What I’m Thankful For…..
Not much to post about today for the short term, but some long-range musings. We could see a flake or two in the mountains as the cold front falls apart over us today. Then it’s dry and sunny with highs in the 50′s at lake level and 40′s on the mountains through next week.
I have been scouring the patterns looking for any sign of when Winter might return in December. Right now the PNA teleconnection pattern is going positive as you can see above. That favors the building of a ridge along the West Coast. A La Nina favors a negative PNA so this positive PNA shouldn’t last that long. Looking at the long-range forecast it looks like the ridge is going to amplify Northward all the way up into the Gulf of Alaska forming a block and keeping the storms up into Alaska and Canada.
The Euro shows the ridge a little further West which would drive some of that Arctic air from Alaska down the West Coast. That would also bring the chance of light snow. Other models like the GFS keep the ridge a little closer keeping the cold air just to the East. We will have to see exactly where the ridge sets up because we could get into a very cold, snow showery pattern starting next weekend if the ridge sits far enough West. All of that record breaking cold in Alaska would love to drop down the West Coast if the ridge moves up there and drives it South.
When there is high pressure blocking in the gulf of Alaska is that sub-tropical jetstream can come underneath into the West Coast. In La Nina with the colder water along the equator there really isn’t a sub-tropical jet to do that. The wild card would be the MJO as it can create psuedo El Nino conditions and juice the jet for about a week when it moves through the Pacific. Right now it is strengthening in the Indian Ocean as it circles the globe.
I know some of you roll your eyes because it doesn’t always work out with the MJO like this week. But the ridge this time would not be over the Southwest, it will be in the North Pacific so the jet would have nowhere to go but underneath. Of course this is just me playing with things in the long-term and looking for anything to get us back on track with snowfall. Hopefully real snowfall the next time we get some.
One of the other things to watch above on the maps is the Arctic Oscillation forecast as it is trending towards negative in December. That would aid in displacing the cold air in the Arctic Southward as warm air builds in the Arctic. That can push the jetstream South down the Coast over time and bring us plenty of cold as well. Last year we saw a coupling of that and the jetstream coming under the Pacific ridge fpr a months worth of snow in a week.
We will have to continue to watch but for now it’s at least 10 days of quiet weather. Happy Thanksgiving to everyone. I am thankful this year for my wife, two kids 1 & 3, being able to be with friends & family this year, my health, being able to live in some of the most beautiful places, and for all of you that continue to read along or discuss the weather with me. It’s great knowing there are so many other snow obsessed people out there. Thank you….BA
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