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Stratosphere and Polar Vortex Watch


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4 minutes ago, bluearmy said:

Big issues becoming ever more apparent with the gfsv3 and it’s handling of the strat 

remember that this is the first winter we will have seen the model in action high up and it’s continual disagreement with the gefs is a worry - add the ec op to this ...........

Well we know from previous year the gfs old version wasn't really that good in forecasting the stratosphere, often it would miss the oscillation at the tail end and end up overshooting forecasting almost always way too much decrease. In previous years the gfs basically saw a ssw at the end of each run for the entire winter 

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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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46 minutes ago, bluearmy said:

Big issues becoming ever more apparent with the gfsv3 and it’s handling of the strat 

remember that this is the first winter we will have seen the model in action high up and it’s continual disagreement with the gefs is a worry - add the ec op to this ...........

I just don't see how you can spend millions developing somthing and then release it without a long period of testing in which you iron out issues. 

Imagine it misses the whole thing altogether?

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4 minutes ago, ALL ABOARD said:

I just don't see how you can spend millions developing somthing and then release it without a long period of testing in which you iron out issues. 

Imagine it misses the whole thing altogether?

The FV3 I believe was tested for about 5 years, the stratosphere was something barely recognized in the testing phase or at least in the presentations about the new model. Time will tell I guess, keep the negatives until the event has happened and then we can see who is right! 

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1 hour ago, Allseasons-si said:

Warming starting to appear now at 10hpa,Up she goes.

pole10_nh.thumb.gif.b58234f147a7847412c9d2de97436888.gif

wave 1 forecast.

jikei_uep_nh.thumb.gif.88ec72783cc33c82f980fad2eada4bc9.gif

Yes - initial wave 2 action is complete in providing a little stretch, and now we have displacement wave 1. I noted last night the return of a strongish aleutian low signal in mid Decemberin EC ENS output, and this may be the beginning of the third phase of stratospheric vortex grief as wave 2 complications return.

So far the December prognosis is following the broad script, though if anything the blocking pattern that may sustain through the first week of December is better than hoped for. If displacement can set the vortex up for a substantive third blow in the latter part of the month then we have some proper interest in downwelling impact chaos....assuming the descending eQBO can get in on the act in January and assist with the frictional downwelling process.

We are still at the lips licking stage.....

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1 hour ago, bluearmy said:

Big issues becoming ever more apparent with the gfsv3 and it’s handling of the strat 

remember that this is the first winter we will have seen the model in action high up and it’s continual disagreement with the gefs is a worry - add the ec op to this ...........

What's wrong with the EC op? Cant see anything there to cause alarm really?

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27 minutes ago, Catacol said:

What's wrong with the EC op? Cant see anything there to cause alarm really?

He might mean the new GFS is also disagreeing with the ECM as well as the GEFS, the only 'upgrade' to the GFS from what i can see is it is now poor in the strat as well, annoyingly now as there seem to be less EPS 360 strat charts posted these days by Micheal Ventrice etc, so could ruin my enjoyment of an SSW should we get one, see the Model thread analysis from Steve Murr over last week to illustrate the GFS still has the same old problems with the lower atmosphere as it always had.

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1 hour ago, feb1991blizzard said:

He might mean the new GFS is also disagreeing with the ECM as well as the GEFS, the only 'upgrade' to the GFS from what i can see is it is now poor in the strat as well, annoyingly now as there seem to be less EPS 360 strat charts posted these days by Micheal Ventrice etc, so could ruin my enjoyment of an SSW should we get one, see the Model thread analysis from Steve Murr over last week to illustrate the GFS still has the same old problems with the lower atmosphere as it always had.

Learning this means that the GFS FI is hard to buy into if it is modelling the Strat incorrectly. ECM has a polar high at 240 yet the GFS is in turbo mode. 

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2 minutes ago, Snowman. said:

Learning this means that the GFS FI is hard to buy into if it is modelling the Strat incorrectly. ECM has a polar high at 240 yet the GFS is in turbo mode. 

Mind you it looks like the GFS is going to be right in one regard now as SSW looking very unlikely now.

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6 minutes ago, Connor Bailey Degnan said:

Just watched the Met Office Live today and makes grim viewing for the potential warming. Now expected to be relatively minor, with little affect, and a return to a strong vortex by late December. ?

Not suprising to me if im honest.Think a strong vortex is likely well before the end of Dec too.

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1 minute ago, northwestsnow said:

Not suprising to me if im honest.Think a strong vortex is likely well before the end of Dec too.

biggest worry is only the odd straggler had an SSW in late winter too, need to hope the GLOSEA5 performs like it did last year.

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20 minutes ago, feb1991blizzard said:

Mind you it looks like the GFS is going to be right in one regard now as SSW looking very unlikely now.

ECM still has a fairly strong wave event and warming at D10, I know the GEFS are still supporting some serious damage so why is a tech SSW looking unlikely?

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1 minute ago, Snowman. said:

ECM still has a fairly strong wave event and warming at D10, I know the GEFS are still supporting some serious damage so why is a tech SSW looking unlikely?

Meto office video talking of something minor and a strong PV later in Dec.

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1 minute ago, Snowman. said:

ECM still has a fairly strong wave event and warming at D10, I know the GEFS are still supporting some serious damage so why is a tech SSW looking unlikely?

They have used the GLOSEA5 just and it shows lowest zonal winds around 10 m/s, i doubt the strat expert would have talked so bullishly about it being a minor event if the EPS ext were disagreeing and that is also why the EC46 is throwing out mild runs so it looks like the GEFS are on their own, stratobserve hasn't updated yet to see what the 0z gefs were like.

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5 minutes ago, feb1991blizzard said:

They have used the GLOSEA5 just and it shows lowest zonal winds around 10 m/s, i doubt the strat expert would have talked so bullishly about it being a minor event if the EPS ext were disagreeing and that is also why the EC46 is throwing out mild runs so it looks like the GEFS are on their own, stratobserve hasn't updated yet to see what the 0z gefs were like.

Fair enough hopefully it turns out to be incorrect.

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21 minutes ago, Snowman. said:

ECM still has a fairly strong wave event and warming at D10, I know the GEFS are still supporting some serious damage so why is a tech SSW looking unlikely?

Briefly, the ensembles have overdone the weakening throughout this period so far, just six days ago the 00z ensemble mean wind for today 06z was 15.2 ms compared with today's analysis of 21.6 ms.

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27 minutes ago, northwestsnow said:

The very fact we are pretty much reliant on a SSW for any hope of cold is another matter.

And yet here comes a cold spell following a near record high strength SPV. :oldsmile:

The SPV is on average at the peak of its strength come the end of Dec, so any prediction as such is going to be reasonable based simply on climatology. Nobody knows for sure though, as shown in the Simon Lee paper above. The Feb 18 SSW was not forecast by any model even at 12 days out.

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Further to the Simon Lee tweet above about things sometimes changing rapidly. From his wave-breaking paper:

Quote

 

In both ECMWF and NCEP systems, the 29 January ensembles showed no members indicating mean easterlies during this period, with a tightly clustered ensemble. The following day, forecasts from NCEP substantially changed, with some members suggesting a mean zonal wind reversal and the entire ensemble forecasting weaker U1060 than the 25th percentile of the ensemble from the previous day


 

We don't have access to archive GEFS or the ECMWF medium-range, but we do have the GFS Op archives on Meteociel.

First, the GFS 0z T384 10hpa from Jan 29 2018:

gfsnh-10-384.png

...and the next day at T360:

gfsnh-10-360.png

 

 

 

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1 hour ago, Yarmy said:

Further to the Simon Lee tweet above about things sometimes changing rapidly. From his wave-breaking paper:

We don't have access to archive GEFS or the ECMWF medium-range, but we do have the GFS Op archives on Meteociel.

First, the GFS 0z T384 10hpa from Jan 29 2018:

gfsnh-10-384.png

...and the next day at T360:

gfsnh-10-360.png

 

 

 

That would have been the old op, not the V3 which was running in parallel at the time. i think its the reliability of the V3 which is being questioned 

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2 minutes ago, bluearmy said:

That would have been the old op, not the V3 which was running in parallel at the time. i think its the reliability of the V3 which is being questioned 

but we know the old GFS wasn't reliable concerning the stratosphere, the new version could hardly be worse

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3 hours ago, feb1991blizzard said:

They have used the GLOSEA5 just and it shows lowest zonal winds around 10 m/s, i doubt the strat expert would have talked so bullishly about it being a minor event if the EPS ext were disagreeing and that is also why the EC46 is throwing out mild runs so it looks like the GEFS are on their own, stratobserve hasn't updated yet to see what the 0z gefs were like.

Feb just for reference go back to December 2017/January 2018 were you were posting the same tweets from the met office stating that GOLSEA5 wasn't showing a SSW, in fact it only saw a weakening of the SPV whilst other models were more bullish. We all know what happened next ?

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