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Stratosphere and Polar Vortex Watch


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19 minutes ago, georgiedre said:

What would this mean?

 

It would mean that blocked patterns would be likely to affect the weather down here, if the high pressure blocks position themselves favourably, it could mean cold weather for the UK - recently they haven't been favourably placed, but that could change easily.  In particular it means that a rampant trop vortex, which would cause mild wet and windy weather for the UK, is unlikely in the foreseeable.

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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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6 minutes ago, lorenzo said:

That's a great chart knocker - Matt sent it earlier... it's a squeeze but we also have an Atlantic wall of warming for it to squeeze against.

For that view the 50hPa run is incredible, complete carnage.

Post it up then - i will use it as my avatar!!

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Stratobserve charts from today's GFS 0z maintain the signal for a strat trop disconnect in the NAM plot:

image.thumb.jpg.3ad0621941e1c2153fd242edfc79e619.jpg

Zonal winds:

image.thumb.jpg.d36bd63e8a07e2e853d1f494b412fef5.jpg

The odd ensemble member getting pretty close to a reversal there.  Interesting!

And the strat vortex T384;

image.thumb.jpg.ad71356ef0fddcc44d71090dc928574d.jpg

And the vortex at the bottom displaced away from Canada.  

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5 hours ago, northwestsnow said:

^^

Knowing our luck it will pan out exactly as Matt alludes to in his last sentence.

I much prefer a warming canadian side ...

Hasn’t this been the issue for the last few years?

Edited by Don
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6 hours ago, northwestsnow said:

^^

Knowing our luck it will pan out exactly as Matt alludes to in his last sentence.

I much prefer a warming canadian side ...

Quite possibly this could happen, the conditions on the surface will then be dictated by the position of the jetstream and its strength.

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17 hours ago, northwestsnow said:

^^

Knowing our luck it will pan out exactly as Matt alludes to in his last sentence.

I much prefer a warming canadian side ...

With displacements more often than not we end up on the warm side. We need a split for cold and then a single split not the weird triple daughter vortices we ended up having, with a smaller daughter stuck in Greenland and no place to go. 

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Looks like a Wave1 assault to follow wave2.

ecmwfzm_ha1_f240.thumb.gif.dfefcdb9d6f4746a73ab4f98df646038.gif

Nice to see the 0 appear in the scale. I wonder if or how long before we get the odd member dip below?

u_60N_10hpa_gefs.thumb.png.5d91b9b4378a3f1900141ac036267273.png

And interesting to see that has already been acheived at 65N...

u_65N_10hpa_gefs.thumb.png.1eb3c985f56576480b3c8133344d1aa6.png

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2 minutes ago, s4lancia said:

Looks like a Wave1 assault to follow wave2.

ecmwfzm_ha1_f240.thumb.gif.dfefcdb9d6f4746a73ab4f98df646038.gif

Nice to see the 0 appear in the scale. I wonder if or how long before we get the odd member dip below?

u_60N_10hpa_gefs.thumb.png.5d91b9b4378a3f1900141ac036267273.png

And interesting to see that has already been acheived at 65N...

u_65N_10hpa_gefs.thumb.png.1eb3c985f56576480b3c8133344d1aa6.png

Maybe the new GFS is better but last year and the years before GFS always overestimated the decrease in zonal winds more than a week out. It regularly saw the ssw 6-8 weeks too early 

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33 minutes ago, ArHu3 said:

Maybe the new GFS is better but last year and the years before GFS always overestimated the decrease in zonal winds more than a week out. It regularly saw the ssw 6-8 weeks too early 

It did at least correctly pick up early on on the U-wind decrease through December and projection of the SSW itself.

But you are correct, it did get the timing of the subsequent SSW quite wrong from its very earliest projections.

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Sad because strat forecasts are generally more reliable but in light of this, it might be a year to stick to the ECM op 240, pity we haven't got the EPS strat charts.

Edited by feb1991blizzard
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5 minutes ago, feb1991blizzard said:

Sad because strat forecasts are generally more reliable but in light of this, it might be a year to stick to the ECM op 240, pity we haven't got the EPS strat charts.

Ecm operational also overestimates the decrease in zonal winds but less so than GFS. In previous it was still about 2 weeks too early 

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1 minute ago, ArHu3 said:

Ecm operational also overestimates the decrease in zonal winds but less so than GFS. In previous it was still about 2 weeks too early 

I actually think the GFS op around 2012 and 2013 was very reliable with the strat, you would get a timing issue with SSW's - generally at 384 it was about 5 days too aggressive but thats not bad at that range, also it used to have the odd rogue run with either an SSW with the daughter vortices in totally the wrong place or actually put the SSW back too far.

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15 minutes ago, coldwinter said:

Of interest 

 

 

Presumably this is data from the current GloSea runs (or run singular), and not those that have generated the DJF forecast (which would have been from the October runs)? It looks like an SSW for early Dec, but hard to tell if it's a major one without seeing the actual numbers.

As for the westerlies at 500hPa...well yes, but if it ran forward a few more days/weeks...?

Edited by Yarmy
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Just now, Yarmy said:

 

Presumably this is data from the current GloSea runs (or run singular), and not those that have generated the DJF forecast (which would have been from the October runs)? It looks like an SSW for early Dec, but hard to tell if it's a major one without seeing the actual numbers.

As for the westerlies at the surface...well yes, but if it ran forward a few more days/weeks...?

Yep, be interesting to see if they continue to show that, higher chance of unsetlled early Dec, but then  possible downwelling in time for Christmas. Interesting stuff, so many things going on this winter!

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