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Pattern December to Remember

SnowNiner said:
Well the GEFS finally got the reds and oranges off MBY at 384! So there's that! I do like the -NAO with a real/true 50/50 low signature (NO WAR, YAY!! hope that stays!). Hate the orientation and location of the pacific ridge, too west and south. Polar air still comfortably tucked in west out in Canada. Still not very optimistic with only the -NAO on our side but we'll see. Perhaps if the Alaskan Ridge could connect to the Greenland Ridge, then that's a whole new ball game, but not seeing that other than the CFS.....lol.

I look at December as being the time to establish the pattern for the upcoming winter. The theme so far continues to be cold trapped out west as far as the eye can see, and potentially -NAO. Maybe our -NAO CAD will be colder this year, I don't know. My guess at this point is that's the theme of winter, mostly warm, with bouts of CAD and threats of CAD events. Hopefully it'll get cold enough to push us past the misery of the constant cold rain events of last year.

gfs-ens_T2ma_nhem_65.png
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Yeah the Pacific ridge seems like it's going to be hard to move. Therfore we'll most likely fight the -PNA most of the time. I do think the -NAO will do work seeing it's not a full blown Canadian blowtorch like last December. I would like to see it a tad more west like the GFS op showed, but like you mentioned without the WAR and having lower heights in the 50/50 region I feel fairly good about it. It's definitely not a shutout pattern and seems to be coming at the coldest time of the year.
 
bigstick10 said:
I am talking about the extended, warm....No real end in sight...I am a huge winter weenie :eek:, but we have to face reality....
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Relax, seriously, don't get too worked up about "extended warmth", the reality is we don't have a clue what the end of the month into January will bring. There is tons of volatility in the pattern moving forward and maybe we torch but we could easily winter storm and if your expecting wall to wall cold in hot 'lanta then your setting yourself up for major disappointment, regardless the year or state of the climate.
 
packfan98 said:
Phase 3? I guess the MJO might sling shot across the middle of the circle? Seems like in the past couple of years we've seen the Euro dampen out the wave too quickly and it ends up correcting with a more amplified wave that goes around the circle. It will be interesting.
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You honestly couldn't ask for a more favorable-looking MJO forecast than what the Australian BOM ACCESS Model is spitting out, stalls in/around phase 8 + COD in early-mid January

mjo_rmm.daily.20211211.png
 
packfan98 said:
That looks great. Is this a closer projection of what you are thinking compared the the Euro?
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It's unrealistic to expect the MJO to move from the West Pacific to Indian Ocean that quickly unless we were in an El Nino winter. Most NWP models have a weak and fast bias w/ the MJO; I wouldn't expect a return to the Indian Ocean until mid-January at the very earliest. More likely we don't get there til late January or so & even then, it takes weeks for the mid-latitude circulation pattern to reshuffle and adjust to the new forcing.
 
Webberweather53 said:
It's unrealistic to expect the MJO to move from the West Pacific to Indian Ocean that quickly unless we were in an El Nino winter. Most NWP models have a weak and fast bias w/ the MJO; I wouldn't expect a return to the Indian Ocean until mid-January at the very earliest. More likely we don't get there til late January or so & even then, it takes weeks for the mid-latitude circulation pattern to reshuffle and adjust to the new forcing.
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I also should mention that the RMM MJO index also tends to lose the MJO in phases 8-1 because OLR doesn't track the MJO terribly well in the western hemisphere. There could be some interference w/ ENSO as well that's projecting onto the index. I.e. those divebombs back to the COD may not be real
 
Webberweather53 said:
It's unrealistic to expect the MJO to move from the West Pacific to Indian Ocean that quickly unless we were in an El Nino winter. Most NWP models have a weak and fast bias w/ the MJO; I wouldn't expect a return to the Indian Ocean until mid-January at the very earliest. More likely we don't get there til late January or so & even then, it takes weeks for the mid-latitude circulation pattern to reshuffle and adjust to the new forcing.
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That's good news, as I get the feeling we're really going to need to keep the -NAO for us to have winter threats next month. I'd love to have a piece of the PV get stuck under the block in Maine. Maybe I've been looking at Larry's CFS posts too long.
 
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SD said:
Eps mean was lower with heights in the east from about 180 onward and cooler at 850 & sfc through that time frame for the most part.

Here is the spreadView attachment 97763

Look at how long the boxes and whiskers are getting. Not much agreement on the middle percentiles much less the overall spread post 12/23.

Here is the plume view. Looks like there's 2 camps with not a lot in the middleView attachment 97764
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This uncertainty in the ensembles shows up daily with the operational runs past day 6. Some runs show winter storms and extreme cold for the SE and flip to beach weather and back again.

The one constant is a fridge source region. Beats the heck out of hoping for the strat warming +3 week unicorn to establish cross-polar flow. So there's that.
 
SnowNiner said:
That's good news, as I get the feeling we're really going to need to keep the -NAO for us to have winter threats next month. I'd love to have a piece of the PV get stuck under the block in Maine. Maybe I've been looking at the Larry's CFS posts too long.
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The -NAO can help accentuate MJO propagation across the W Hem and into the Indian Ocean (as I've mentioned previously because of the increased equatorward wave fluxes that accumulate in the subtropics), but that takes at a minimum ~2-3 (usually more like 3-4) weeks after onset of -NAO. However, even then, there's an additional lag/adjustment period in the mid-latitudes that comes with new wave trains emanating from this forcing having to circle back around the globe and alter the pre-existing circulation anomalies, so tack on no less than an additional 1-2 weeks on top of that. Assuming -NAO onset begins in earnest ~ Dec 20-25, it would be no sooner than later in the 2nd week of January for this new Indian Ocean MJO to negatively impact the pattern (of course that doesn't mean something else wouldn't be capable of doing that in the meantime). We should have at least 2-3 weeks of a decent-great pattern to play with this year.
 
SD said:
The 6z gfs cutting the ridge off over AK then slowly moving it east into Canada makes me feel a certain way.
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That would certainly be unusual as most of the time those -EPO/Alaskan blocks retrograde towards Siberia & become -WPO. Oth, if the Pacific jet were to extend/speed up, it's possible the westerly advection by the mean flow may be able to overcome the beta advection induced by the ridge itself. Fwiw, phase 8 Dec does tend to favor +PNA (La Nina of course makes that harder), but still that's interesting from a general pov.
 
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