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Pattern December to Remember

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MichaelJ said:
To sum up the teleconnections on the 12Z runs, All have a strongly negative NAO/AO and a less negative EPO. The WPO is negative to neutral and the PNA stays strongly negative. The surprising thing to me is how close to the same forecast are for the CMC and the ECMWF, haven't seen this much before. Here are the CMC and Euro on the NAO
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Here is the AO for CMC and ECMWF
1639785600-O5LJl7WNf4Ygrb2.png



1639828800-u15vWsCx07Ygrb2.png

A striking correlation.
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Thanks for posting these, which give me hope for a cold dominated pattern to eventually get here, especially if the PNA at least gets close to neutral.

So, the EPS/CMC mean has the AO getting down to a -4, which if accurate would imply a peak perhaps down to near -4.5 to -5 like the controls have. GEFS is similar with mean down to near -3.5.

For whatever reason, unlike the AO, WxBell maps have always inflated NAO by factor of ~~1.7 vs what is commonly followed (NCEP). You can tell by looking at today and the next few days and comparing to the GEFS runs per NCEP. NCEP has todays actual at -0.87 vs the WxBell Euro near -1.5. WxBell shows a forecast peak near -3.1 on EPS/CMC. The record NCEP met winter peak is only -2.5, which was on 12/22/1978. (OTOH, WxBell AO is ~the same as NCEP’s AO.) But even after reducing the WxBell -NAO peak of -3.1 to get it in line with NCEP, I still get -1.8, which is not much lower than the NCEP GEFS peak forecast near -1.6 and would still mean a very strong -NAO. The last met winter day with a -NAO that strong was way back on 1/4/2011, when it was -1.9. With an implied EPS/CMC mean peak near -1.8 and a GEFS mean peak near -1.6, a -2.0 peak wouldn’t at all be surprising thus maybe getting to the levels of 2010-11.

So, in summary, today’s ensemble forecasts imply to me a shot at a late Dec -AO peak of -5 and -NAO peak of -2. That combo would be very high up on the strong -AO/-NAO scale if verified.
 
NickyBGuarantee said:
Torching out there right now! Luckily rain accompanies it.. plus we knew this was happening! Boring. Glad we’re tracking a pattern change now right in time of most everyone’s thinking of late December to early January .. all going according to plan
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What? There’s a plan? And it’s all going according to it ? Your studying meteorology right? My goodness these are some famous last words “ all according to plan”. Pretty sure the captain of the Titanic said that before he hit the iceberg.
 
Here comes the massive Arctic outbreak at hour 384 once again. Some things never change. E763C136-8060-438B-BC54-47C623594844.png
 
GFS not nearly as cold as the Euro. ?
 
Lickwx said:
What? There’s a plan? And it’s all going according to it ? Your studying meteorology right? My goodness these are some famous last words “ all according to plan”. Pretty sure the captain of the Titanic said that before he hit the iceberg.
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According to how the pattern looked like it was going to play out for the past month … chill out man read a book
 
I think the bottom line is much higher than normal uncertainty for SE US very late Dec into a good portion of January. The ensemble member spreads are higher than normal I believe. The battle between the persistent La Nina favored -PNA with some help from +AMO and warm Maritime Continent and the very strong upcoming -AO/-NAO is not something seen often. Let’s get ready to rumble!
 
GaWx said:
I think the bottom line is much higher than normal uncertainty for SE US very late Dec into a good portion of January. The ensemble member spreads are higher than normal I believe. The battle between the persistent La Nina favored -PNA with some help from +AMO and warm Maritime Continent and the very strong upcoming -AO/-NAO is not something seen often. Let’s get ready to rumble!
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?️⚡⛈️
 
Seems like we’re eventually gonna get something to slide under the block, eventually…. Can’t cut much with a -NAO, even last year with a AK/west coast pacific barrage we constantly saw things slide under the block
 
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