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Long Range Pattern Drivers & Evolution Thread


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2 hours ago, donsutherland1 said:

One final thought on the potentially major implications of the recent EPS MJO forecast (as it provides some insight into the things I look at in developing my thoughts)...

 

The forecast shows the MJO emerging into Phases 4 and then moving into Phase 5 at a high and increasing amplitude during the extended range:

 

MJO12282019.jpg

 

The composite temperature anomalies for December-February MJO phases are below:

 

MJO-Composites-DJF.jpg

 

For New York City, the below table shows data for the January 10-20, 1981-2019 period for all dates and for dates when the MJO was in Phases 4 or 5 at an amplitude ranging from 1.000 to 2.000:

 

MJO12282019-2.jpg

 

One important caveat: At the current timescale, MJO forecasts have relatively low verification. Therefore, such a scenario is not cast in stone. Greater clarity should develop over the coming week.

 

MJO is very complicated as to sensible weather outcomes. You have those times where composites are close & then you have those where it's no where close. 2 Examples...both El Nino winters:

 

1) JAN 1-15, 2015, MJO in phases 5,6,7 produced this:

 

Screenshot_20191228-222559_Chrome.jpg.dc37d1fffad0474bd6aab3598a568a29.jpg

 

Screenshot_20191228-222803_Chrome.jpg.9ef0a1f0c4975297edb6523fb7436af0.jpg

 

Screenshot_20191228-223656_Chrome.jpg.91bbd886c8c8e61a5a8c6d53f0d9decf.jpg

 

 

2) JAN 26 - FEB 6th, 1978, phases 5,6,7

 

Screenshot_20191228-222900_Chrome.jpg.1400e98b25628e65277aac4909d66480.jpg

 

Screenshot_20191228-223107_Chrome.jpg.97761ac8f2f15624bd8f33e7b729db83.jpg

 

Screenshot_20191228-223607_Chrome.jpg.81feb5704ac28129c43b701bcf3a65a4.jpg

 

Both are examples of the opposite of what you'd expect. I'm not even remotely implying anything other than providing 2 examples & of course there are others where composites are not helpful. There is the lag to consider with MJO & background state etc...

 

Just food for thought 

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Hey Tom. I did not favor a warm Nov or Dec. I thought the effects of the NPO-induced cold would first start out West in December; and when the NAO eventually relaxes for a time, we would get some warm

The shifted west tropical forcing from traditional Niño, or even Modoki, has created a stronger Subtropical High in western Pacific / Hadley. This has promoted the return of the "Kamchatka Low" which

Back on December 26, composite date for MJO passage at high amplitude in Phase 4 and historic data associated with strong AO+ patterns in combination with a positive EPO implied that the GEFS was miss

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Okay the flip is real boyz and GEFS are harping bigly. 

Jan 7-9 time frame has big showing analogs for major east coast storms when you have a high energy sun cycle and when Jupiter is in perigee within 5 degrees of earth's equator.  

 

IMG_20191229_002026.jpg

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11 hours ago, 33andrain said:

Interesting blocking development at the end of the GEFS.

gfs-ensemble-all-avg-nhemi-z500_anom-8938400.png


Yes - and for the Atlantic this would fit with the relative AAM plot posted above. Note the ever so faint suggestions of jet undercut to the south of the UK high. Things getting interesting, though by 13 Jan the peak of the momentum surge will have passed and is the pattern likely to flatten out again?

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51 minutes ago, Catacol said:

I feel duty bound to modify my pessimism of yesterday immediately having just spotted this out on Twitter. Changes things just a bit, changes things quite a lot actually....

E990ABE2-89C9-4026-A8A1-408F51ABA4DC.jpeg.c9ea0e4a49ec9c4b67a54ffc50bbb48b.jpeg
Cue more potent wave breaking and likely increase in the amplitude of the wave pattern. Weather watching has a habit of making monkeys of any forecaster the moment he/she thinks things are “nailed”. I guess that’s why it’s so addictive....

 

For the UK (not what 99% on here are interested in I know, but I’ll put it out there anyway) this increases the chances of the current Euro high edging north and maybe (just maybe) opens a door to @PB GFI retrogression of that anomaly to the west if momentum is angled just right. Maybe EAMT aligned to assist? Still think it unlikely - but a fair bit less unlikely (if that makes sense) than was the case yesterday and now I’d keep my money in my pocket...🙂

 

👍 Seems related to the Okhotsk Sea low @antmasiello_HM pointed out on Twitter the other day. That this would lead to increased cyclonic wave breaking and keep winter alive. 

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2 hours ago, 33andrain said:

Pretty much everyone has identified ~1/10 as a period during which we may see snow. When Pb will really earn his stripes is if any warm up after that is transient and if January can finish closer to N. 

 

I agree, the 5 to 7 day window I was arguing is opening and you , @donsutherland1, @mbaer1970 and others have also liked.

I had a hard time buying the ridge idea in the east in the day 5 to 11 period.

There's too much Positive in Alaska which made the ridge in the east garbage.

 

@Catacol yeh, just maybe it works the GEFS has the retrogression of the Scandinavian ridge but the EPS turns the EPO negative, I just don't know who ( if any ) are right.

Personally I want a - EPO but I need to see the MJO over the next few days to see where this forces.

 

The EPS at day 12 looks suspicious to me, the negative is centered in W Canada but further east than yesterday at 12z.

So that has a chance to adjust east. 

 

Now what's ahead of that ? I like the idea of big EC storm in the 8 to 10 but if that happens,the models look correct in pulling the trough out.

( If you deepen LP like the models portray, that happens ).

 

So if the ridge returns how long ?  I think its transient also it's not a torch because the flow into the Rockies will be super cold and even though the air downsloping modifies it will not torch because of it's source region.

( see the mean air flow from the NE of Alaska ).

If the - EPO turns negative that low level cold air will sweep SE.

 

I will write something more in depth later.

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I would treat ALL of the LR Rimm plots with skepticism and look outside of the MJO after day 10 because these models really do struggle when seeing multiple areas of convection

 

 

This loop never occured and it had people declaring Jan dead.

FF019E29-35B2-4B44-9C78-155687103C72.jpeg.dcec8284514c679b07f948f03eaa34fa.jpeg.jpg

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2 minutes ago, PB GFI said:

I would treat ALL of the LR Rimm plots with skepticism and look outside of the MJO after day 10 because these models really do struggle when seeing multiple areas of convection

 

 

This loop never occured and it had people declaring Jan dead.

FF019E29-35B2-4B44-9C78-155687103C72.jpeg.dcec8284514c679b07f948f03eaa34fa.jpeg.jpg

Every year these plots screw with winter forecasts.  Like you said they are terrible past a week out 

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2 hours ago, PB GFI said:

I would treat ALL of the LR Rimm plots with skepticism and look outside of the MJO after day 10 because these models really do struggle when seeing multiple areas of convection

 

 

This loop never occured and it had people declaring Jan dead.

FF019E29-35B2-4B44-9C78-155687103C72.jpeg.dcec8284514c679b07f948f03eaa34fa.jpeg.jpg

 

Again look at the GEFS correction in the near term , in just one day,  many members are into p8 and its amplitude in the null p sags closer towards 1 more today then it did yesterday.

 

I lot was made of its run towards 5/6 by d15 , but it's near term corrected more favorable today.

 

Its cousin the CFS thinks the convention in 8/1 mitigate the convection that goes off in 6 in the longer term so it takes it from 8 into 1 and then 2.

 

20191229_132416.jpg.cefabb9790107bcb2ad0f1c78933b923.jpg20191229_132428.jpg.bf52e46089c2ea3baff9541fc312eb94.jpg

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1 minute ago, antmasiello_HM said:

 

This feature is the amplification of the stationary wave. The background state has given it some power, esp. with the periods of West Pac forcing. It prevents long duration +AO/WPO/EPO regimes. All sensible weather aside, you see the difference in the analogs over the pole between the big vortex years and years with the Chuchki. 1.JPG.fd20345a34a4f9ff161ca77099ff432e.JPG2.JPG.bc921bc2d6b5895eb8d81823366eb860.JPG4.JPG.37793d4e2a1daeec66d574599834d967.JPG

 

It's not necessarily the biggest influence on temperatures here unless combined with other factors. With a less hostile Pacific, you can pull off a 1958 or 1960 like response:3.JPG.3d99b3a013f3421fb9a17ba49e0e7af4.JPG

 

 

 

Anthony,  when I look at the vp 200 anamolies I see 2 areas of convection day 7 and 14 one near 8 / 1 the other ( stronger near 5/6 ).

 

It is my position that the forcing near 8 will help turn the EPO negative as it sends a negative east of Hawaii forcing the ridge near Alaska and displacing the TPV.

 

I continue to think the natural correction in the LR is to deamplify ridging in the east in the LR.

 

How do you see that?

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