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Pattern Dazzling December

I’ve just heard the the Euro/EPS Have a bad reputation for developing +PNA’s that don’t verify. I understand your point though


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This is exactly right. In my personal opinion the models will continue to falsely hint at a major cold air intrusion for mid December…and then mid to late December…and then late December…and so on. There is simply NOT ENOUGH COLD AIR to work with over our part of the Northern Hemisphere. Most of the cold has been sloshed to parts of Asia and Siberia because of anomalous heights across the North Pacific AND North Atlantic, cutting off a stream of expansive deep cold to North America. Conventionally, the NAO is good for snow and cold across the south and east. NOT THIS TIME. What defines success out of the NAO is it’s ability to Push and redirect cold air south. When our source region is inadequate and the FOX ISLAND, Alaska high remains more than stubborn, we can expect what cold that does exist on our side of the NH to be redirected and consistently pushed west and southwest to the -pna trough extending from eastern Alaska, through the west Canadian coast, and down to California. Until the North Pacific waters cool and the high pressure mass over Alaska’s Islands dissipates we can expect the NAO currently in place to NOT mean much for cold and snow in the Eastern US!
 
The issue is though, Is that it’s looked like this at hour 240 for the last couple of days. Keeps pushing back.


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I’ve been critical but this seems like the closest it’s been. I’m starting to truly believe this big time snowstorm in the in the northern plains coming up will set the stage.
 
This is exactly right. In my personal opinion the models will continue to falsely hint at a major cold air intrusion for mid December…and then mid to late December…and then late December…and so on. There is simply NOT ENOUGH COLD AIR to work with over our part of the Northern Hemisphere. Most of the cold has been sloshed to parts of Asia and Siberia because of anomalous heights across the North Pacific AND North Atlantic, cutting off a stream of expansive deep cold to North America. Conventionally, the NAO is good for snow and cold across the south and east. NOT THIS TIME. What defines success out of the NAO is it’s ability to Push and redirect cold air south. When our source region is inadequate and the FOX ISLAND, Alaska high remains more than stubborn, we can expect what cold that does exist on our side of the NH to be redirected and consistently pushed west and southwest to the -pna trough extending from eastern Alaska, through the west Canadian coast, and down to California. Until the North Pacific waters cool and the high pressure mass over Alaska’s Islands dissipates we can expect the NAO currently in place to NOT mean much for cold and snow in the Eastern US!
A -EPO from west pacific tropical forcing would take care of all those problems
 
The issue is though, Is that it’s looked like this at hour 240 for the last couple of days. Keeps pushing back.


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The change always had a "deadline" of around mid month, which is the last day of the Euro. Anything before that was always going to be bonus in my opinion. Now if we get to the end of this weekend & we still see the same cold air mass just arriving across the Central US at HR 240, then we have to begin to question many more things on what we thought was going to happen.
 
Euro has certainly been putting out some eye candy the past few runs.

View attachment 124943
About as classic a look preluding a Deep South snow as you get. Positive tilt S/W dives SE as the Aleutian low builds in, pumping the west coast ridge. The PV lobe over the Hudson always a concern for shearing, but it’s reality for winter in the south. Gotta live on the knife’s edge to get snow.
 
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1671343200-JpoplP1XIVs.png
 
About as classic a look preluding a Deep South snow as you get. Positive tilt S/W dives SE as the Aleutian low builds in, pumping the west coast ridge. The PV lobe over the Hudson always a concern for shearing, but it’s reality for winter in the south. Gotta live on the knife’s edge to get snow.
Eye candy n is that severe threat been showing
 
EPS wasn’t as good as I expected, kept lower heights stuck in the west View attachment 124944View attachment 124945
I’m not too concerned with that as smoothed put mean. The individual members still strongly support the good pattern. Also I just had a chance to look up the updated teleconnections today and they continue the consistency they’ve been showing for the last week or so. Strongly
-NAO relaxing somewhat from about the 15th on but still holding negative. The PNA reaching neutral, maybe just slightly positive around the same time. -AO holding and the MJO hanging out in the COD to low amp 8-2…. Hard to complain about that. The other thing is that is important to remember is that much of the south can get cold enough for winter weather even with the coldest in Asia… it’s happened quite a bit. Canada is staying cold and there’s been nothing to flood things up there with mild Pacific air like we saw for much of December 2020.
 
This is exactly right. In my personal opinion the models will continue to falsely hint at a major cold air intrusion for mid December…and then mid to late December…and then late December…and so on. There is simply NOT ENOUGH COLD AIR to work with over our part of the Northern Hemisphere. Most of the cold has been sloshed to parts of Asia and Siberia because of anomalous heights across the North Pacific AND North Atlantic, cutting off a stream of expansive deep cold to North America. Conventionally, the NAO is good for snow and cold across the south and east. NOT THIS TIME. What defines success out of the NAO is it’s ability to Push and redirect cold air south. When our source region is inadequate and the FOX ISLAND, Alaska high remains more than stubborn, we can expect what cold that does exist on our side of the NH to be redirected and consistently pushed west and southwest to the -pna trough extending from eastern Alaska, through the west Canadian coast, and down to California. Until the North Pacific waters cool and the high pressure mass over Alaska’s Islands dissipates we can expect the NAO currently in place to NOT mean much for cold and snow in the Eastern US!
The Euro gets there. Like I said earlier, establish the EPO ridging and you'll get an efficient buildup of cold air in Canada. And we don't need all of it to come from Siberia. It's dark up there in the Arctic. Cold will build up if you block the Pacific. Would like to see troughs quit setting up along and off the west coast, though. It's becoming quite annoying.

ecmwf_z500_mslp_nhem_65-1.png
 
I’m not too concerned with that as smoothed put mean. The individual members still strongly support the good pattern. Also I just had a chance to look up the updated teleconnections today and they continue the consistency they’ve been showing for the last week or so. Strongly
-NAO relaxing somewhat from about the 15th on but still holding negative. The PNA reaching neutral, maybe just slightly positive around the same time. -AO holding and the MJO hanging out in the COD to low amp 8-2…. Hard to complain about that. The other thing is that is important to remember is that much of the south can get cold enough for winter weather even with the coldest in Asia… it’s happened quite a bit. Canada is staying cold and there’s been nothing to flood things up there with mild Pacific air like we saw for much of December 2020.

If the NAO switches to positive wouldn’t it take 2 weeks to effect the pattern?


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