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Stratosphere and Polar Vortex Watch


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27 minutes ago, Paul_1978 said:

But will be the vortex be displaced where we want it or where we don't want it!

Exactly, could end up over Greenland and Boom, more rain. let's hope our luck changes and we get an actual split!

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Some useful tropospheric developments upcoming which are likely to have stratospheric impacts towards the end of November and more particularly into December. A strong convectively coupled tropic

so after many days the GFS & FNMOC & canadian finally now follow the Euro with 44 out 64 Members with a split at day 9- The ECM is day 8. We will call it - SSW & Split for 1st Ja

For all that watch the zonal winds. Let me urge you to look at the geopotential heights more. At least as far as weakening/strengthening trends go. Because as the polar vortex cries for help, you migh

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32 minutes ago, Paul_1978 said:

But will be the vortex be displaced where we want it or where we don't want it!

Would be impossible to tell at this stage but it will mostly be considerably weak wherever it ends up so not the end of the world. 
 

You only need a wedge of heights and a cold Europe to get some snow going but it’s easier said than done!

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1 hour ago, Paul_1978 said:

But will be the vortex be displaced where we want it or where we don't want it!

EC has it moving towards Scandinavia and then probably to Siberia, which probably won't be too bad for us since it leaves Greenland open for building heights 

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23 hours ago, ArHu3 said:

EC has it moving towards Scandinavia and then probably to Siberia, which probably won't be too bad for us since it leaves Greenland open for building heights 

49 minutes ago, s4lancia said:

It's been a few weeks since zero has even been showing in the scale!

u_60N_10hpa_gefs.thumb.png.a1cb667b59ab0ded60c24963b93c6e4b.png

Hopefully from small acorns etc...

 

Vortex certainly getting squeezed at the top as decent strength wave activity continues.

ecmwf1f216.thumb.gif.ad6bc09cf00b9aafdea612a48f45011e.gifecmwf1f240.thumb.gif.9d717ab97c41d73296287d8753bb8e17.gif

Wasn't the 2018 SSW that gave us the beast from the east a Siberian warming at the strat level? Not sure if they follow the same pattern with regards to the impact at trop level each time but if they did.....(ps - I've just started learning about all this so go easy on me if I say anything obvious/stupid - cheers ? )

I've also read that there's more chance of a displacement of the PV rather than split in a QBO-E phase but then I've read about more chance of a split when there's planetary wave 2 activity, so I'm a little unsure of what's going to happen. (Again I might be getting confused as I learn but does any of this makes sense?)

One thing I know is its fascinating learning all about this....keep up the great analysis all - it makes for great reading.

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50 minutes ago, s4lancia said:

It's been a few weeks since zero has even been showing in the scale!

u_60N_10hpa_gefs.thumb.png.a1cb667b59ab0ded60c24963b93c6e4b.png

Hopefully from small acorns etc...

The 10-day GEFS mean from December 7th 00z for December 17th 00z was 19 m/s, the eventual GFS analysis value was 52.9 m/s, just saying.

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1 hour ago, Interitus said:

The 10-day GEFS mean from December 7th 00z for December 17th 00z was 19 m/s, the eventual GFS analysis value was 52.9 m/s, just saying.

Did any model come out of this strong uptick with any merit ???

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23 minutes ago, feb1991blizzard said:

Arguably the GLOSEA5 but that is being pedantic - not many shorter range models.

Not sure that Exeter would see it as pedantry ……. vindication of what they consider to be the best strat model out there more like ……  that's assuming it had a reasonable verification on the past two weeks 

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1 hour ago, bluearmy said:

Did any model come out of this strong uptick with any merit ???

This chart shows GFS day 8 vs GEFS day 5 since 7th November. Over the whole period they have a similar RMSE, but while the GFS got the recent peak fairly accurately eight days in advance, the ensembles didn't even 3 days later.

GFSd8vsGEFSd5.thumb.png.e7b5e49f0b61c07d572bd34516161403.png

Indeed the GEFS only showed a mean >50ms for the first time at 3 days prior to the peak whilst when the GFS cottoned on it showed >50ms at day 10 -

GFSd10.thumb.png.2db6243e74ede6ba55dc82b6eff2c4d9.png

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18 minutes ago, Interitus said:

This chart shows GFS day 8 vs GEFS day 5 since 7th November. Over the whole period they have a similar RMSE, but while the GFS got the recent peak fairly accurately eight days in advance, the ensembles didn't even 3 days later.

GFSd8vsGEFSd5.thumb.png.e7b5e49f0b61c07d572bd34516161403.png

Indeed the GEFS only showed a mean >50ms for the first time at 3 days prior to the peak whilst when the GFS cottoned on it showed >50ms at day 10 -

GFSd10.thumb.png.2db6243e74ede6ba55dc82b6eff2c4d9.png

Andrej had commented that gfsv3 was reasonably reliable in the strat … clearly the gefs aren't.  would still stick with ecm when available …..

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2 hours ago, bluearmy said:

Not sure that Exeter would see it as pedantry ……. vindication of what they consider to be the best strat model out there more like ……  that's assuming it had a reasonable verification on the past two weeks 

Quite - meant pedantic as in you were probably referring to the models suites you can see for yourself, I think it did predict the uptick as t am assuming the GLOSEA is what they were using in their charts on their video with their strat expert. Agree with you re ECM and that is why i was never completely convinced with the earlier strat warming, I still think the old GFS was not actually that bad in the strat on the proviso that you understand how to use it and its inherent biases.

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5 hours ago, Interitus said:

The 10-day GEFS mean from December 7th 00z for December 17th 00z was 19 m/s, the eventual GFS analysis value was 52.9 m/s, just saying.

Yep, it was shocking just how far off the mark the GEFS were. December'18 they were a week or so out on timing, but other than that, were there or thereabouts correct with the U-wind slowdown and eventual reversal / and duration of.

I'd like to think this is a perfect case study for NCEP to find out what happened this year that their forecast system did not pick up on (or why their forecast system got it wrong in the first case and carried on running with it)

Makes you think maybe last year they just got lucky!

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9 minutes ago, SqueakheartLW said:

The 12z GFS today is really going for the SSW this time.

gfsnh-10-384.thumb.png.20593bf4cf1061b8a0c641520000e7b0.png

Highest 10hpa temperatures on this run at +384 hours at -4C

yeah its been throwing out warmings all through autumn.

i wouldn't bank on it until jma and ecm have a sniff of it.

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14 minutes ago, ArHu3 said:

If the trop vortex follows these purples we're screwed , southwesterlies until spring 

That's not how it works.

 I can't even be bothered....

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