Don’t Drive Yourself Mad….
I know that many of you are sitting around anxiously awaiting the next run of each model like me. It’s enough to make you go crazy. Normally at this time of year I am looking at how much snow will fall with the next storm before talking about the long-range. Now for the past 6 weeks it has been all long-range which is easier in some respects but harder in others.
The forecast models starting pulling away from the big precip yesterday and continued into today before some of the models are now flipping back more towards storms next week. This is normal when a big pattern change is coming and it has been happening on the long-range models for a week now. It will continue probably for a few more days until we get within about 5 days of when the first storms would arrive.
Nothing has really changed in the forecast models through next weekend. They still show the ridge shifting North and then setting up South of the Aleutians towards the end of the week and then up into Alaska next weekend. What is different among the models is what happens with the ridge next week. The trend yesterday and today was for the ridge to shift West over the Bering Sea. That would setup the blocking a little too far North and West, and would keep the storms just to our North.
It is still really early so we will most likely see the models continue to flip back and forth. The ideal location for the ridge would be South-Southeast of the Aleutian Islands which is South of the Bering Sea which would push the jetstream further South down the West Coast. Then more East towards 160w would help to keep the flow from the Northwest keeping enough cold for snow. It is going to be a long week of watching where the ridge sets up by this time next weekend.
Even if the storm track stayed just to the North and we ended up dry if would not be the same reasons as now. Some people are saying the models are showing the same pattern for the next few weeks which is not true. We have had a trough over the Aleutians and into Alaska and what seems certain is that there will be a ridge next week. It’s just the placement of the ridge that is critical.
The Arctic Oscillation at the top of the page is not right as the NWS is working on fixing the black line. It is still slightly positive but it continues to go negative which will increasing blocking the next few weeks which is much different than the pattern we have had. Some or a lot of the blame for the lack of snow over the country goes to the AO being positive so far this Winter. Here is a look at the NAO forecast off of policlimate.com through the end of the month.
Lot’s of Arctic Air coming South and blocking setting up in the North Pacific is something we have been waiting for as a possible change in the pattern, and this can cause it. With the stratosphere continuing to really warm I don’t think there is any doubt that the AO is going negative over the next few weeks. That will make the weather interesting no matter what the models are saying.
Let’s take a look at the 12z Euro from today for next weekend. You can see the ridge still develops to the South of the Aleutians and over Alaska and the cold to the East is coming down the West Coast.
But here is Tuesday the 17th showing the change we saw the past 24 hours wi the ridge shifting West into the Bering Sea. That allows the ridge to build off the CA coast as the Pacific NW gets hammered.
That is a ridge over Alaska though not a trough or big storms like the past month so see even if the storm track is just North next week it’s not for the same reasons or the same pattern we have had. We want the ridge at around 50n and 160w for the storms to come underneath the ridge into CA as cold comes down from the North.
The latest 18z GFS had the ridge further South and had plenty of snow with Tahoe on the South side of the storms hitting the Pacific NW. It just wasn’t the major storms it was showing 2 days ago. Hang on because we are most likely in for more of this roller coast this week. Stay tuned…BA
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