EasternLI

28 minutes ago, LibertyBell said:

I've seen that a SSW is forecast for later in December?

I don't know if I'd call for one, but it absolutely looks to be one option. Fascinating watching things unfold right now as a long range aficionado. 

La nina has been taking shots from the high AAM state (el nino like). Westerly wind has been punching holes in the trades. That didn't happen at all last year. What looks like a strengthening la nina trade burst upcoming, looks to be related to the jet extension at that time. Amplifying the return flow in that period. We'll see what happens after that.

5 minutes ago, snowman19 said:

It’s favorable, however, the twitterologists are sharing the wrong MJO phase 8 composites. They are sharing +ENSO composites which features +PNA, the correct composites, which is -ENSO, December, MJO 8, show the -PNA/RNA which is to be expected in the current -ENSO background state, especially with a firmly entrenched, healthy La Niña like we have now. It’s still favorable (-AO/-NAO, -EPO/-WPO), however the -PNA obviously supports the western troughing seen on the ensembles

Well stop looking at them, then lol

6 minutes ago, Allsnow said:

Looks like p8 at some point in December which is usually cold in the east 

It does. There's a lot going on. 

Tropical eps still looking good. Like the 12z yesterday, basically. 

1 minute ago, EastonSN+ said:

We can definitely score in that look.

Well yeah, but my point is, December SSW follows that look if we follow the Ural Blocking playbook. 

Here's something pretty cool. 12z eps at the end. Doesn't look very inspiring locally. But it's interesting nonetheless, as the next step from Ural Blocking would be a -NAO/Cold siberia pattern. Which is pretty much this:

I agree. Beautiful day today. 

I also agree with @bluewave

A guarded optimism is how I'm going. The tropical looks have had a large spread in the longer term between individual members. Saw that last year too. Need things to settle down some. Different looks this year though. We're getting some nice ones more often than not and the picture is not similar to last year, to me. Record Pacific warm pool driving the record -pna last year. We don't have that this time. The AAM state is also completely different. The volcano from last year is a wild card. The NAO look is legit. 

We do seem to see some nice ingredients this year. Does mother nature forget to set the timer? Or does dinner come out amazing?

TBD 

18z gefs looks good too fwiw. Ural Blocking looked really nice too. A bit earlier. Still interested in that. 

Nice looking tropics too on that run fwiw. 

Can we get a Pacific Jet extension and blast that ridge poleward? That would be fun. 

13 minutes ago, LibertyBell said:

Isn't there a ridge in central Asia somewhere that correlates to blocking for us? I forget what it's called.

 

I think you're thinking about a Siberian high? If so, they're related. The GEFS is actually showing Siberian high pressure at that time for example. 

I mentioned that November could possibly hold more clues about winter. We're discussing the tropical aspects, which are very interesting in their own right. But there's still more to the story. 

It's also seemingly a month with persistent Urals blocking. The ensembles continue that theme until the end of the month. Here's the 5 day mean from the gefs for example. Plus 500mb obs from NOAA for the month so far. 

Why would that matter?

That needs to be watched because it has potential to force a December SSW. And that leaves open the possibility of a -AO winter. The following paper explains how that's possible. Another fascinating possibility to watch for.  We'll just add it to this year's list. It's getting pretty long. 

Ural Blocking as a Driver of Early-Winter Stratospheric Warmings

8 minutes ago, LibertyBell said:

Interesting if we could trace all this back to the blocking we had in October lol

That would be great. However there seems to be too much variance during October. Recent research suggests. November however, may hold many more clues. Recent research also points towards that being the case. 

We watch, we wait. -NAO does have some support to be real this December for once. Due to actions taking place this month. We seem to be on a path less traveled this year. Should be interesting. 

24 minutes ago, bluewave said:

Yeah, forcing over South America is more in the MJO 8-1 region favoring a -NAO. So if I it’s strong enough, it can push back against a more hostile MJO phase 6. We saw something like this during the December 2010 La Niña. The Pacific was very hostile for the first 25 days of the month with the La Niña and Maritime Continent MJO 5-6 region forcing. While December 2010 blocking was historic, even a slight improvement on the Atlantic side can try to mute the influence of a more hostile Pacific. So we may start December with competing influences and whichever is stronger winning out. 
 

 

Exactly. It keeps it interesting to see what may happen. This is different than what we've seen recently too. The AAM charts posted by Matt Hugo on the main board are something I haven't seen in a long while. With -aam propagation poleward. Something that I remember HM talking about in regards to northern blocking years ago. Very interesting circumstances abound currently. 

Some La nina + QBOW + MJO thoughts:

It's interesting this year. La nina plus a WQBO favors keeping the MJO from really reaching the Pacific.

Combined effect of the QBO and ENSO on the MJO

"During La Niña/QBO westerly years, the MJO over the Maritime Continent is suppressed because of the strong Maritime Continent diurnal cycle, and it is further suppressed over the western Pacific because of the lack of a reinforcement process."

But that's already occurred in the autumn. I'm thinking the Kelvin waves have contributed to this action. Since they've been active and these same factors don't apply to them in that way. Helping it along?

These are multivariate MJO obs from the JMA site. One based on OLR and one based on VP. 

So let's say its possible we repeat something similar to that in December. We know there's a phase 7 - negative NAO connection. La nina and a westerly QBO gets interesting now. Because even though that would argue against it happening in the first place. When it does occur under those conditions there would theoretically be a stronger response. 

Modulation of the MJO-Related Teleconnections by the QBO

"During the westerly phase of QBO (WQBO), a stronger and longer lasting MJO‐NAO teleconnection is observed."

ENSO Modulation of MJO Teleconnections to the North Atlantic and Europe

"Conversely, the MJO to NAO− regime stratospheric teleconnection is enhanced during La Niña years and suppressed during El Niño."

So what ultimately happens? We'll have to wait and see but it's an interesting picture. 

I would highly recommend not driving through lake effect. Been there. The hood starts to disappear....

Just a fwiw post, but I find it promising to see this action by South America during the 2nd half of November. If the hope is to avoid a ratter of a la nina. The lousy la nina years did not do this. Some of the better ones, did. I find this extremely interesting and thought it was worth a mention. 

Let's do this 

32 minutes ago, Terpeast said:

Have we seen a pattern like this at the end of the last 2 autumns? 

I'm thinking if we're seeing this now, this may repeat at least a few more times throughout this winter.

Well, that does seem to be a possibility at least. 

SWFE = SWmehE

2 hours ago, Allsnow said:

Next weekend will probably be real warm 

Yeah, next weekend is looking nice. Sign me up please.