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Model output discussion - proper cold spell inbound?

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GFS: I dunno what to do.. so, I'll just move the entire polar vortex lobe slowly Eastwards. That seems likely 

GFS.thumb.png.0f1f7c3e8fd5b89b8f8fa46d03406004.png

The GFS is utterly clueless here but despite that, it still manages to develop blocking to the North

Whats that, 9/9 runs or something showing blocking now? It wont transpire like that, I don't think I've ever seen the vortex move like that and I've looked through a lot of archive charts, I was a lonely teenager at times.

Bin anything from the models beyond T120, once the SSW has actually taken place, things will start to become clear. Shannon Entropy as we move forward until then.

Edited by Daniel Smith

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2 minutes ago, Daniel Smith said:

GFS: I dunno what to do.. so, I'll just move the entire polar vortex lobe slowly Eastwards. That seems likely 

GFS.thumb.png.0f1f7c3e8fd5b89b8f8fa46d03406004.png

The GFS is utterly clueless here but despite that, it still manages to develop blocking to the North

Whats that, 9/9 runs or something showing blocking now? It wont transpire like that, I don't think I've ever seen the vortex move like that and I've looked through a lot of archive charts, I was a lonely teenager at times.

Bin anything from the models beyond T120, once the SSW has actually taken place, things will start to become clear. Shannon Entropy as we move forward until then.

I’ve missed Shannon. 

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I imagine a west based neg NAO outcome in a couple of weeks would put a few on here ‘over the edge’ !

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19 minutes ago, bluearmy said:

I imagine a west based neg NAO outcome in a couple of weeks would put a few on here ‘over the edge’ !

I've already fallen off the 'edge' after this latest 'Killer' Freeze...not!

Edited by Froze were the Days

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Someone get some hangover coffee at the ready for the control 

 

4E31833C-EF16-4A3A-B11A-D1427277FD84.png

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58 minutes ago, ITSY said:

I’ve missed Shannon. 

The less shannons the better:diablo:

anyway a late night for me tonight of catching up after work

and i would just like to be clear in that there is and will be for a few days so much model divergance until this is resolved allbeit in our vicinity of heights showing up to our NE in FL,please keep your seatbelts fastened,it could be a bumpy ride and hopefully to a smooth one

that warming gives us a big smile over N Canada though on the 12z 10hpa and in saying,i have kicked the other sister out of the back door,bye! bye!:aggressive:

gfsnh-10-252.thumb.png.79d5176a10e7ad3993d33b91faec6da5.png

 

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1 hour ago, ITSY said:

Why are people so passive aggressive on a weather forum? Baffling. The Sudden Stratospheric Warming is not “so called”. It has a 66% historic correlation with significant downturns in UK temperature. If you don’t like those odds, then move country or get a new hobby. 

I’d arguably say it’s 80% + with what we’re looking at as is often the case by anyweather I’m left baffled :p GFS 12Z op itself showed a fairly quick 7-10 day response (nearly got there) after reversal on 12th.

Edited by Daniel*

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Delete

Edited by snowray

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1 hour ago, Quicksilver1989 said:

I think people are making an assumption that an SSW equates to UK cold. Be careful... a split polar vortex could see  a lobe fall over Greenland or NE Canada which would see cold air outbreaks over other areas of the Northern Hemisphere. It is fascinating but quite a new area of meteorology, so no assumptions should be made for this SSW to bring a big swathe of cold to our shores. The risk of cold air outbreaks across the mid latitudes is much higher with an SSW but where that falls is open to interpretation.

Don't get me wrong, SSW's increase the chance of UK cold but it may not result in a tanking NAO and the prolonged cold people on here crave.

Some swings in the model output are expected. A colder then normal late February has a chance of occurring but don't be surprised if we are in the wrong place and end up with mild SW winds instead.

People won't like reading it, sorry though that's the way it is. The 18z GFS is just one run though. A warming climate means we should be apprehensive about the colder solutions verifying because atmospheric circulation patterns are changing.

A very pessimistic post. A split historically favours us much more than across the pond furthermore with a strong warming projected in Greenland itself, only ehances the sheer unlikeliness I feel blocking in Greenland is definitely possible I can’t see a problematic lobe in the vicinity. Sorry don’t agree with you too nothing fundamentally in atmosphere has changed - which will override signals? A tad bizarre - we haven’t had anything significant disturbance in stratosphere for years such is why they excite folk, and this one looks not the average SSW this is the real deal in years to come I see this being discussed. There is absoloute zilch what is showing SW’ly flow Azores high is set to be sent packing, Jet Stream too nothing mild is coming that I’m sure of.

“Using reanalysis data it is found that vortex splitting events are correlated with surface weather and lead to positive temperature anomalies over eastern North America of more than 1.5 K, and negative anomalies over Eurasia of up to −3 K.”

https://www.google.co.uk/amp/s/wattsupwiththat.com/2014/02/08/when-does-a-displaced-polar-vortex-becomes-a-split-vortex/amp/

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Certainly some big changes in the output occurring over relatively short time periods

Check out today's UKMO 144 and yesterdays GFS 06

UN144-21.GIFgfsnh-0-162.png

A perfect example of how the models have continually failed to pick up trough disruption until nearer the time and of GFS progressive bias.

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It will be interesting to see what eventually happens with the lobe of PV out to the NW through the mid term though.

The Euros so far have been keen push and organised lobe across the Atlantic while GFS wants to largely have it remain in situ and have it spin off small areas of low pressure at its base.

I actually see GFS as being more probable in that respect of the output but who knows? 

gfsnh-0-144.pngUN144-21.GIF

Edited by Mucka

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Nice GFS with easterly sweeping through Europe and reload at the end.

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Ensembles trending down still, long may it continue. :)

graphe3_1000_259_88___.gif

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Fairly good agreement between ECM and UKMO regards behaviour of the trough - GFS odd one out

ECH1-144.GIF?08-12UN144-21.GIF

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I just wonder..... ECM edging towards a better run when looking northwards. I expected detachment of any Atlantic trough from the NA vortex and then a trend for weakening and undercutting of this detached trough as heights increase to the east. We shall see but at T+168 without my glasses on I can see the trend.

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ECM looking great at 192, this could bring the cold in earlier although hopefully not to far west 

 

F7A504E7-948A-48D5-ABFA-29862BE0697D.png

Edited by Ali1977

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Very nice looking GFS FI run an easterly flow from 234 to 384....I'd take it!  Some superb looking charts in there.

312 gfsnh-0-312.png?0 384 :shok: gfsnh-0-384.png?0

As Mucka says, good set of ensembles as well.  I've also noticed that the first strat warming has slightly lengthened and the second warming is a little more intense. 

138 gfsnh-10-138.png?0 228 gfsnh-10-228.png?0

It's all looking very positive at the moment, but plenty of time it all to go titicus verticus.

Oh, and the ECM is climbing aboard at 216 with heights shooting up to Greenland..... I need a lie down after all that lot.

ECH1-216.GIF?08-12

Edited by Ice Day

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12 minutes ago, chionomaniac said:

Interesting at T+192. I think we can safely say that the ECM has finally woken up to the fact that a SSW is occurring......

Interesting and good synoptic but not as good as it could be. I would much rather not have the trough stall over us and then slowly fill even with the Atlantic ridge showing. Much better for it to stall further West and disrupt some energy SE IMO, but then I'm impatient.

ECH1-216.GIF?08-12

Edit.

That said if we do get this I won't be complaining in 10 days time. :) 

Edited by Mucka

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5 minutes ago, Sneachtastorm said:

What utter nonsense 

Think this is talking of the strengthening Azores ridge and stronger to the south. Certainly might not be nonsense. Anyway if the Ssw comes off favourable it would wipe those anomalies out so onwards to the search particularly for the last week of Feb:)

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