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Stratosphere and Polar Vortex Watch


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As a layperson, I'd say those are both possibilities to some extent, in that several recorded SSW have occurred, however no two are that much alike.  So, yes, perhaps a difficulty for those who have to write the programming for the models is how much emphasis to give the myriad of factors when there is limited data from previous events upon which to base those emphases.

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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

Posted Images

Great 12z runs from GFS and UKMO, starting to reflect what has been / still is a record breaking SSW event. Some of these charts are going to have to have the max / min parameters re drawn :D to list just a few below

5a81ccc1a33cb_ScreenShot2018-02-12at17_18_19.thumb.png.ce632402e9336ac2baf485e090653060.png  5a81ccc8840cc_ScreenShot2018-02-12at17_18_52.thumb.png.6c3db5d7fb90982007a18f63b2771c17.png  5a81ccce32112_ScreenShot2018-02-12at17_19_11.thumb.png.8218683e2cdd303391347dd55be43f2f.png

My personal favourite....

5a81ccb66d047_ScreenShot2018-02-12at17_17_53.thumb.png.70a624140010a70cbcab245a45871cc4.png thats an all time record breaker right there for that height and latitude OOOFFFTTT 

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5 hours ago, bluearmy said:

Pretty good assessment imo. I think the establishment of blocking to our north/northwest may be a few days earlier than you summise. 

The original modelling of the strat split carried the Asian chunk around the growing  block across mainland Europe allowing an easterly to establish quite quickly - slowly but surely, ecm And eventually gfs took this chunk further north until it phased to our northwest  with the Canadian segment extension. I think this is the easiest way to understand why we haven’t seen a quick trop response affect nw Europe.  

npst30.png npst30.png npst30.png

 

Decided to see what the latest from GFS was on that Asian chunk and it just so happens that what I was looking out for (by way of pure hope) actually manages to transpire on both the 06z and 12z; the warming on the Canadian vortex periphery cuts off the segment before it's able to merge with the Canadian vortex.

It then cycles back around and has another go, but by that time it's very weak and the ascending ridge (latitude-wise) has already had time to establish in the troposphere. For good measure, a third warming then prevents the merger anyway and the ex-Asian segment finally fades away. 

npst30.png npst30.png

 

I have tried looking on the I W Ms page at 50 and 70 hPa and it appears that the merger comes very close but doesn't quite make it at those levels too. 

Of course this only really counts for much if ECM also starts blocking the merger from happening. Waiting and wondering...

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Well, it’s not often we get the full SSW deck showing...

From7D3A04EB-F4D7-493D-9868-AF323FC862E9.thumb.gif.838aa9c57530bab9ae81dce298bec73f.gif

To F7AD19C4-62AE-4502-8287-A3CFE463B4C0.thumb.gif.d05b7b95a7b374932e533a9a889b90bb.gif

To infinity and beyond!

OK, probably not, but I would think looking at it.. we may be able to squeeze another 2 or 3 days out of it? Even if not, this is probably an event that will be talked and written about for many years to come.

Edited by s4lancia
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1 hour ago, knocker said:
No sustained easterly then :shok:
 

 

Anthony has picked out a composition that results in best -NAO for the Eastern US. 

March 2013 would have featured had it resulted in a colder outcome for our cousins in the states. 

Watch the migration of the Euro HP- Travels west over UK, into the Atlantic and up towards Greenland. Gave them a late winter in 2001 with large amounts of snowfall.

2018’s -NAO is to travel NE from the Atlantic towards Scandi and then NW towards Greenland. 

Synoptics are very different. Outside influencing factors are also different.

I believe the US will get their West based -NAO in week 1 into week 2 of March, as the tropospheric PV moves Westward and breaks out into lobes. 

 

 

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Robbing Anthony's effort in building the PV gif that tells the story of the vortices... nightmare indeed! 

Untangle those ENS!

 

From a few days ago things were looking a lot more robust for that Canadian lobe, it's getting a right doing at 10hPa.

ezgif-1-f786c070fb.thumb.gif.77f60b5c37d5cb490e17aacd63ac276c.gif

And, on tadpole watch, it tries it's damnedest to return to source, only to be shut down by perfect timing.

ezgif-1-53012557d3.thumb.gif.326b4bbc0dfc081e041662c4da8ea2e8.gif

Looks to my eye that 19/20 is the timing for resolution of this strat vortice saga..

 

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On 2/12/2018 at 12:44, KyleHenry said:

The ECM sees the reversal. It’s just not within the range of the 10 day model outputs of this past weekend.

My post was in reference to those that were  writing off the SSW effects by not seeing the tropospheric response showing an Easterly with every output. When the time table was always pointing towards 21st-25th Feb, if all proceeded as expected. 

Minor displacements in the Stratosphere give us a -AO, I expect the same and much more from this event.

I felt that if the ECMWF’s Stratosphere and Troposphere modelling were in sync, that it would show the formation of a significant-AO. That didnt happen and therein lays my sole criticism of the ECM

As for the GFS, it sees the signal, it just doesn’t know where and what date to proceed with the correct solution. 

Ive put a timetable of my expectations and upcoming events and expect to die on my sword for trying to be an SSW oracle. All good.

Right I read you :) 

Most model ensembles are now hinting with blocks, just a lot of variation in position and timing. 

It's an interesting idea to think to what extend the models perform with stratospheric configurations that are several sigma's away from normal conditions. To what extend are models calibrated to handle (or to what extend do we understand strat-trop coupling?) vortex remnants moving from east to west like in the coming 72 hours?

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5 hours ago, JeffC said:

Warming up continues, now as "warm" as -8.2c which is pretty balmy for 10 HPa!

https://earth.nullschool.net/#current/wind/isobaric/10hPa/overlay=temp/orthographic=3.22,89.46,373/loc=-73.205,68.391

 

Seems to be up to -3'C above Cape Dorset now? 

strat.png

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28 minutes ago, NorthernRab said:

Seems to be up to -3'C above Cape Dorset now? 

strat.png

it's not so easy to find the warmest place when using a Kindle! -you're right  - -3.3C that's pretty toastie for 10 Hpa!

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Guys, saw a chart the other day where Dr Butler was predicting a -37.5m/s wind reversal - can anybody point me in the right direction of what actually verified if indeed the SSW has peaked yet?

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41 minutes ago, supernova said:

Guys, saw a chart the other day where Dr Butler was predicting a -37.5m/s wind reversal - can anybody point me in the right direction of what actually verified if indeed the SSW has peaked yet?

I think it’s peaked at around -25 m/s at 60N 10hpa.

Edited by bluearmy
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