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Stratosphere and Polar Vortex Watch

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8 minutes ago, bluearmy said:

Assuming it verifies, unknown rob ...... last winters ssw didn’t propagate effectively ....

 and would this evolve into a ssw?  Would it be a displacement?  Or would it become a split ?  And if it did propagate, how would the shattered tpv be left ?  Most strat warming’s seem to become notable in that particular part of Asia. 

Hehe - so many possibilities. I’m going to plump for a split, and I’m also going to suggest residual energy will end up over Canada and East Asia. Surface impacts will be different to last year with favourable QBO context by January smoothing a path to a better downwelling. It’s all in my forecast over on the speculation thread (though I don’t discuss the QBO shape in that write up in an attempt to keep it from being mammothly long) - but a short spell of Canadian vortex induced weather leading to a definitely blocked pattern by the latter half, maybe final third, of January.

This winter is really “hotting” up.

Edited by Catacol

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3 minutes ago, mushymanrob said:

what are the implications at surface level for a warmin in that location?  (novice here)

Also a RELATIVE novice myself on here but that is the start of a warming, if it just flirts around the surf zone then fizzles out, it will either have negligible effects or it will be impossible to tell what effects as it would be such a small displacement, however, if it gets right into the pole and either significantly displaces the vortex or splits it in 2 (these events the most favourable to bring freezing weather to the UK) then its a question of whether it leaves an imprint on the troposphere but the default pattern for the UK following one of these events if they are 'successful' is high pressure somewhere between Iceland and Scandinavia and potentially bitterly cold Easterly winds. Last years didn't really do the job, it was a trickle down event (displacement initially), just my personal opinion and others will pick me up if i am talking rubbish but as well as splits being more likely to bring a cold spell, to me events with a quick trop response seem to have a better strike rate as well. i think overall SSW's have something like a 66% strike rate for bringing cold into the UK.

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6 minutes ago, feb1991blizzard said:

Also a RELATIVE novice myself on here but that is the start of a warming, if it just flirts around the surf zone then fizzles out, it will either have negligible effects or it will be impossible to tell what effects as it would be such a small displacement, however, if it gets right into the pole and either significantly displaces the vortex or splits it in 2 (these events the most favourable to bring freezing weather to the UK) then its a question of whether it leaves an imprint on the troposphere but the default pattern for the UK following one of these events if they are 'successful' is high pressure somewhere between Iceland and Scandinavia and potentially bitterly cold Easterly winds. Last years didn't really do the job, it was a trickle down event (displacement initially), just my personal opinion and others will pick me up if i am talking rubbish but as well as splits being more likely to bring a cold spell, to me events with a quick trop response seem to have a better strike rate as well. i think overall SSW's have something like a 66% strike rate for bringing cold into the UK.

A good summary I reckon. Whether we get a split or a displacement will be key. Displacements carry significant risk in terms of predicting surface impacts. A proper split which downwells fully makes missing subsequent cold much less likely. The pattern that has caused gnashing of teeth and flooding to unfortunate parts of England and elsewhere I think is our ticket to a split, but a lot of crossing fingers to be done over the next 3-4 weeks. No split, minor displacement and reformation by end of January creates a very different picture tropospherically.

Edited by Catacol

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2 minutes ago, Catacol said:

A good summary I reckon. Whether we get a split or a displacement will be key. Displacements carry significant risk in terms of predicting surface impacts. A proper split which downwells fully makes missing subsequent cold much less likely. The pattern that has caused gnashing of teeth and flooding to unfortunate parts of England and elsewhere I think is our ticket to a split, but a lot of crossing fingers to be done over the next 3-4 weeks. No split, minor displacement and reformation by end of January creates a very different picture tropospherically.

Also another thing i have noticed, certainly with mid season events is they seem to really pack some potency when the first bit of Jan has had a very strong trop vortex - 91 and 09 being examples.

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8 minutes ago, feb1991blizzard said:

Also another thing i have noticed, certainly with mid season events is they seem to really pack some potency when the first bit of Jan has had a very strong trop vortex - 91 and 09 being examples.

Yes, probably because anything from mid January onwards coincides with the natural gradual weakening of the vortex and so reformation is less easy for it. A displacement event in early December, given this is still part of the vortex intensification phase, can be quickly overcome. That early January potency allows for residual cyclonic energy to keep enough fizz in the pattern to prevent it becoming stagnant I guess. (I’ve got that fizz in my forecast this year for what it’s worth...)
 

Aleman has just posted Finnish data suggesting a very snowy NH in October has become the snowiest NH for the first half of November on the record. We haven’t even got to the start of winter yet, but this is really lining up to being extremely interesting, not least because long term models are still (mostly) seeing a +NAO season. Is 2019/20 going to the season of the humbled supercomputer, or are many amateur forecasters going to be left licking raw wounds? The balance of multiple amateur and semi pro forecasts is not leaning towards a +NAO end product.

Edited by Catacol

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Apologies for what may be some obvious questions but just trying to learn a bit - 

1. At the moment we have a very unorganised trop vortex that is not coupled to a strong strat vortex? 

2. The strat vortex is forecast to become weaker so does that mean it is likely to become more or less coupled to the trop vortex?

3. What would cause the trop vortex to gain strength as we move into Winter, would that be from forcing's in the trop, strat or both?

4. In very basic terms I think I understand that a weak strat vortex induced by a warming can downwell to help to make a weak trop vortex which makes high latitude blocking in the trop more likely - although where that sets up may or may not be conducive for cold in the UK?

5. Finally, given the current state of the trop vortex is there an optimum time for the potential influence of a warming to strike - ie would it be more effective if the trop vortex reorganises and following on from that would a strat warming be wasted on an unorganised trop vortex (if you see what I mean)?

Thanks in advance.

NS

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Curious amateur question, the 50,30,10 hPa temp anomaly graphs (11d rm) are showing cool colors appearing, low temps over the N/S-Americas and high temps over the N/S-Atlantic.

temp50anim.gif

temp30anim.gif

temp10anim.gif

Can someone tell me what these kind of waves are called? The MJO has been 'gathering momentum?' and is breaking on both sides? Does this ever bridge fully?

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2 hours ago, Northern Sky said:

Apologies for what may be some obvious questions but just trying to learn a bit - 

1. At the moment we have a very unorganised trop vortex that is not coupled to a strong strat vortex? 

2. The strat vortex is forecast to become weaker so does that mean it is likely to become more or less coupled to the trop vortex?

3. What would cause the trop vortex to gain strength as we move into Winter, would that be from forcing's in the trop, strat or both?

4. In very basic terms I think I understand that a weak strat vortex induced by a warming can downwell to help to make a weak trop vortex which makes high latitude blocking in the trop more likely - although where that sets up may or may not be conducive for cold in the UK?

5. Finally, given the current state of the trop vortex is there an optimum time for the potential influence of a warming to strike - ie would it be more effective if the trop vortex reorganises and following on from that would a strat warming be wasted on an unorganised trop vortex (if you see what I mean)?

Thanks in advance.

NS

Thanks Northern Sky I have been pondering the very same questions.

I too would be grateful if any one more knowledgeable could answer the above questions.

Thanks. BB

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GEFS 06Z mean with a bit more yellow 1987285772_gensnh-21-7-384(1).thumb.png.5a462c70e9c9c786977013dfb49afb87.png again wont post them all but here were some of the stronger ones 1295334148_gensnh-6-7-384(1).thumb.png.3a372416d204674e8b32c4a18f8f2293.png 674059603_gensnh-8-7-384(3).thumb.png.015bbe1408124aecad0f3e6072f4752e.png gensnh-9-7-384.thumb.png.8e174cd4a341672a2ec420b6466b12c8.png1362998133_gensnh-20-7-384(2).thumb.png.6f4c0d4fc084b84a41847d47a1afa021.pnggensnh-13-7-384.thumb.png.896fae211544d8b7dd807e0ba1679840.pnggensnh-12-7-384.thumb.png.85cd205152d04a6f85802dc9aecc42f8.png

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The stratosphere is continuing to be much colder than average over the North Pole, however it appears a possible warming trend has commenced at both 30hpa and 10hpa in the last day. 

image.thumb.png.6f8eb124d0ec764cbfac3112f504e888.pngimage.thumb.png.acbfd2fdce83afd67390e6259683f854.png  

Either way, with the continued disconnect between the stratospheric and tropospheric vortices and below average stratosphere temperatures, the Northern Hemispheric patterns are not normal for the time of year.  

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The difference between the gfs op and gefs remains stark .....

zonal winds at day 16 on the 06z op look potientially record breaking high up 

7EC4E059-1827-41F3-A66E-053839B6C338.thumb.jpeg.a435f74210540c8bc11d6f1af5ec29c7.jpeg

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I would say that is the strongest set of ensembles so far from the GEFS 12z again just a few but certainly looking like an interesting period coming up as we head into December 

1611007897_gensnh-19-7-384(2).thumb.png.f4828f294e604b0f423f94f082ce298a.png1522687917_gensnh-12-7-384(1).thumb.png.140fdc6efb4428669ff1f626abfc83f2.pnggensnh-11-7-384.thumb.png.9aa676ac6013f8d3933426e3c7caa274.pnggensnh-10-7-336.thumb.png.3f7bf2806df9be5c849cd0a45db9ebfe.pnggensnh-4-7-384.thumb.png.09e6657c6a4c9d3f852efd2a95d50a5c.png1401346539_gensnh-3-7-384(2).thumb.png.4f5bd46c1f97c8206eda60cc02fdccaa.pnggensnh-2-7-384.thumb.png.40411c751a490de03c8e70a5510b8080.png780701267_gensnh-0-7-384(1).thumb.png.4ab227040209289873a61849b231aa1f.png

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2 hours ago, bluearmy said:

The difference between the gfs op and gefs remains stark .....

zonal winds at day 16 on the 06z op look potientially record breaking high up 

7EC4E059-1827-41F3-A66E-053839B6C338.thumb.jpeg.a435f74210540c8bc11d6f1af5ec29c7.jpeg

Christ, is this a timing issue because the warming up top on the 12z op looks significant, in other words is it a failure due to timing issues on the op or has it got it spot on against its ensemble suite or is it just a spectacular failure and fault of the new FV3 GFS?

EDIT : also, ignore my other posts on criticism of GFS op's past successes / failures or faults wrt SSW timings and zonal winds because they are academic now as its the new GFS of course.

Edited by feb1991blizzard

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24 minutes ago, feb1991blizzard said:

Christ, is this a timing issue because the warming up top on the 12z op looks significant, in other words is it a failure due to timing issues on the op or has it got it spot on against its ensemble suite or is it just a spectacular failure and fault of the new FV3 GFS?

EDIT : also, ignore my other posts on criticism of GFS op's past successes / failures or faults wrt SSW timings and zonal winds because they are academic now as its the new GFS of course.

The 12z was less enthused with that strongest flow generally above 5hpa 

the zonal flow can be strong even with a warming ....there is strong wave 1 in tandem with the increased flow .......that wave 1 would weaken the flow over a coupe of days .... as you say, it’s timing 

Edited by bluearmy

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I also have a similar question to Northern Sky above.... so at the moment we're seeing a trop vortex that's very different to most late autumns and if that was maintained into winter proper, could be good for us? Do we want an SSW now to displace what is an otherwise fairly decent state of a pv?!

Sorry if I'm waaaayyy off the mark, lol! Novice in training here 😉

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10 hours ago, weathergeek said:

I also have a similar question to Northern Sky above.... so at the moment we're seeing a trop vortex that's very different to most late autumns and if that was maintained into winter proper, could be good for us? Do we want an SSW now to displace what is an otherwise fairly decent state of a pv?!

Sorry if I'm waaaayyy off the mark, lol! Novice in training here 😉

Not unreasonable question ...... I would say that without warming’s higher up, an inevitable coupling down here from a very strong vortex high up would occur into December ...... the warming’s are already happening courtesy of the wave 2 and the v strong wave 1 which is definitely coming will ensure we don’t have a monster spv as we arrive into December. Of course, it could then strengthen but the period beyond week 2 isn’t clear.  There isn’t any sign of an ssw at the moment apart from the unreliable forecast products 

Edited by bluearmy

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21 hours ago, Broadmayne blizzard said:

Thanks Northern Sky I have been pondering the very same questions.

I too would be grateful if any one more knowledgeable could answer the above questions.

Thanks. BB

yep, another here interested in learning.....

plus.... december 1981, december 2010, where they as a result of a ssw event? or were those 2 extreme cold snowy decembers unconnected to a stratospheric warming?

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24 minutes ago, mushymanrob said:

yep, another here interested in learning.....

plus.... december 1981, december 2010, where they as a result of a ssw event? or were those 2 extreme cold snowy decembers unconnected to a stratospheric warming?

December 81 saw an SSW on the 4th December - a displacement event, the 2010 December was probably a result of the stratospheric pattern being unable to imprint on the trop because the trop pattern was so amplified right from mid November onwards, there was no major warming in Nov or Dec 2010 up top, just minor warmings, maybe as a result of the trop pattern itself.

 

image.thumb.png.0e194db3e94727383419ad22300e880c.png

 

EDIT : looks like the 81 event was actually as a result of the tropspheric pattern but that did meet the threshold of an SSW, the zonal winds were about -5 m/s, the temps were nothing special at 10mb so doesn't look like a top down event to me.

 

I am busy now but will upload the charts from all levels of the atmosphere later if you like on the NOAA site so you can view the zonal winds, heights and temps to find out for sure what went on.

 

Edited by feb1991blizzard

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Mid November 2010, at 10mb level, there was a very strong positive anomaly over Greenland. The more detailed 30mb on JMA has a mid month split vortex with heights across Greenland to Kamchatka.

1770279951_nov10.thumb.gif.4e32d58053aa497845f1b79935bab31f.gif

I may be wrong on this but my understanding is it is the geopotential height placement rather than the warming that is important. The warming just gets the heights to shift position to a placement that is either good for us or not.

Edited by Gael_Force

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40 minutes ago, Gael_Force said:

Mid November 2010, at 10mb level, there was a very strong positive anomaly over Greenland. The more detailed 30mb on JMA has a mid month split vortex with heights across Greenland to Kamchatka.

1770279951_nov10.thumb.gif.4e32d58053aa497845f1b79935bab31f.gif

I may be wrong on this but my understanding is it is the geopotential height placement rather than the warming that is important. The warming just gets the heights to shift position to a placement that is either good for us or not.

Yes, great post, stand corrected. must still have been trop lead i would have thought as usually top down MMW type events do usually need a big warming event coming around the Eurasian sector.

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The PV IS feeling the squeeze by 180hrs at 30hpa.

npst30-1.thumb.png.0cdff13ff1d0ac513686db1bf20d6f27.png

Long may it continue.... 

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1 hour ago, feb1991blizzard said:

Yes, great post, stand corrected. must still have been trop lead i would have thought as usually top down MMW type events do usually need a big warming event coming around the Eurasian sector.

I think the very strong Nina had a large part to play. Early season Nina forcing promotes the mid atlantic ridge, and so great was the Nina forcing that year that it helped created that most dramatic meridional patterns - and popped the vortex shard over the top of us as a result. Extraordinary. Other factors certainly will have conjoined, but strong Ninas favour early season cold for the UK.

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3 minutes ago, Catacol said:

I think the very strong Nina had a large part to play. Early season Nina forcing promotes the mid atlantic ridge, and so great was the Nina forcing that year that it helped created that most dramatic meridional patterns - and popped the vortex shard over the top of us as a result. Extraordinary. Other factors certainly will have conjoined, but strong Ninas favour early season cold for the UK.

Yes, would concur with that, although there have been some very good very late season Easterlies with Nina's or on the Nina side of ENSO neutral

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GEFS 06z 1492209070_gensnh-0-7-384(2).thumb.png.b37d2c309bb25c65adaca9195244fbfb.png1207105140_gensnh-18-7-384(4).thumb.png.a9b5744ad7ba1d3a71ae081acf6d09fd.png1648265633_gensnh-16-7-384(3).thumb.png.8f79f109f8585d56e8f96d64fff6e997.png1382250174_gensnh-15-7-384(2).thumb.png.8e0e1c76be5082ca407cf725476eb812.png1578362920_gensnh-14-7-384(4).thumb.png.124a583d36b76b9461723fc6e8731dd1.png63283040_gensnh-7-7-384(1).thumb.png.f027988bc6c1b604bab8e1ad2ce2dd76.png35529498_gensnh-3-7-384(3).thumb.png.103a2da7260c1fc72be373a9dd13c73f.png and although I am wary about the GFS given its back and forth nature during last winter (as already discussed) will throw that in too gfsnh-10-384.thumb.png.09286b13bfb6d197c3888c6e9aa31515.png December possibly shaping up to be an interesting month.

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