Model Output Discussion - Deeper into Autumn

[Ice Day]

21 minutes ago, Mike Poole said:

GFS // goes full tonto by the end of the run…

Now THAT is a Greenland high!  

These are pretty much the dream synoptics for us here in the UK.  The two words that spring to mind with both the GFS Op and Para are 'Locked In'!  What do the 0z GEFS tell us about the trend over the last 3 days then?

  

That's a pretty significant trend to colder, both in the mid and long-term.  Now of course this may all come to nothing, which is the default unfortunately for the UK.  But the consistency of blocked runs from all the models leave me feeling unusually positive. 

There's going to be some more ups and downs and I think it's going to take another 3-4 days before we really get a handle of where the high's initially position themselves before we can start concerning ourselves about the weather outside our front window!  But if nothing else, we've had more entertainment from the models than we did for the entirety of last winter!  

Game on for the 12z's.

 

[Tim Bland]

7 minutes ago, feb1991blizzard said:

well everything that fell from the sky here was snow (not much admittedly) and altitude here is very low, add in 4 of the biggest blocks of flats in the uk and the heat generated from them....

Yep, plenty around in north London areas too.. 

[blizzard81]

Nice mean. 

[Midlands Ice Age]

7 minutes ago, I remember Atlantic 252 said:

and here but wet and non settling

Here (further south) -   went for Covid jab  in heavy falling snow... 6 inches fell in 4 hours that morning here.

MIA

[northwestsnow]

1 minute ago, blizzard81 said:

Nice mean. 

That is exactly what coldies want to see.

Vortex removed from Canada/ Greenland..

[feb1991blizzard]

1 minute ago, Tim Bland said:

Yep, plenty around in north London areas too.. 

i only got a light dusting - it melted but only because everyone walks on it and it was so thin - if it would have been a good dumping it would have hung around in the car park anyway.

[Ice Day]

4 minutes ago, blizzard81 said:

Nice mean. 

That's an unusually strong signal for T300.  Very nice!

[feb1991blizzard]

meanwhile GEfS are looking very ridgy around Greenland -

 

[That ECM]

Just now, feb1991blizzard said:

meanwhile GEfS are looking very ridgy around Greenland -

 

That trend has been there but is strengthening day by day. All interesting and good to see.

[johnholmes]

51 minutes ago, Kasim Awan said:

-11.7

Are you pulling our legs predicting 'will it snow' values to the first decimal point?

[Kasim Awan]

1 hour ago, Eagle Eye said:

I'm sorry for anyone who finds my posts (if there's anyone) interesting here just feeling a bit overwhelmed at the moment. Will still do my weekly document write-ups but probably won't post here much as I can't really keep up as we go into the best chance we've arguably had for a while in early Winter. Sorry that this is off topic mods just wanted to let  the 0 people interested. I don't wish to sound egotistical, after all I'm not that well versed in meteorology it's just some people seem to find my posts interesting I guess. It's sort of a half goodbye for now, don't know when I'll be back to my normal mental state though. If I still feel overwhelmed throughout Winter, good luck to everyone. Of course, I may feel better next week I just don't know.

Anyway, my thoughts for now is that if this does happen, it'll be fairly decent away from lowland areas, depending on the exact direction I suppose that North Sea snow showers can occur but whether this will be cold enough to properly cool this coasts remains unknown. I think the main benefit of this is that it could bring snow to areas away from the usual early Winter areas but again, that still remain unknown. I'm not willing to commit to anything really as of yet but the AAM forecasts suggest that we'll see a gradual weakening of the Nino Atmospheric state into next week and lag correlations would suggest the second week of December or sometime around then to be the transition period before a re-entry into the Nino state and so mid to late December, interest may arise again but it's too far away for anything solid.

Your posts are very much appreciated and your knowledge is well above your years. My, even half your knowledge would still be impressive, so don't be pressured into constant detailed writeups etc by the reputation you have built. Take a week off.. this is a demanding hobby and can get the best of us down. Even tho the knowledgable people are respected on here, they should not hold themselves to such a high standard. Not everything in meteorology is linear, someties it's best to just say "I dont know".

[jules216]

I also mentioned in earlier post about a threat of WB -NAO and "All of the sudden" here is latest GFS anomally, there is also that Portuguese trough doing no one any favors. Its just plain ridiculous to have a lovely Scandi blocking transfering to -NAO but not east based, what has happened to Europe since 2011-12 February that every possible cold spell gets scuppered by something.

[Kasim Awan]

14 minutes ago, johnholmes said:

Are you pulling our legs predicting 'will it snow' values to the first decimal point?

It's based on the sounding profile extracted from the gfs 00z op at roughly 270h -  call it -11/-12 based on a strong surface warm layer & a RH of 78%. That would produce a surface DP of -2/-3C under a slight easterly flow - enough for powder snow.

Edited November 26, 2022 by Kasim Awan

[mountain shadow]

3 minutes ago, jules216 said:

I also mentioned in earlier post about a threat of WB -NAO and "All of the sudden" here is latest GFS anomally, there is also that Portuguese trough doing no one any favors. Its just plain ridiculous to have a lovely Scandi blocking transfering to -NAO but not east based, what has happened to Europe since 2011-12 February that every possible cold spell gets scuppered by something.

That anomaly chart does not show a West based-NAO. The High Pressure is almost directly over Greenland. 

At the boundary between the dry cold NE air and the moist SW air, there would be potential for heavy snow.

[Eagle Eye]

14 hours ago, Singularity said:

My eyebrows have raised this evening as GFS has produced a rare 'bottom-up' stratospheric polar vortex split via a trough splitting against Greenland & ECM has something similar by Greenland on the same day (next Sat)..

As far as I'm aware, this is what happened in late Nov 2010, so it's worth keeping an eye on future runs for any consistency regarding the trough split against Greenland.

 

I know I said I wouldn't post for a long time apart from document stuff but this ties in nicely with one of my older documents that I read. If this does happen, a bottom-up split (possible future SSW) event sounds similar to the first part of PJO related to the Stratospheric thermal transport and zonal wind transfer. 

For there to be a Stratospheric asymmetry, there has to be movement away from the mean that causes it. A split is a very good example of that movement away from the mean and note that the atmosphere wants to be in thermodynamic equilibrium. It is clear that on this specific GFS run, there are large deviations from the mean around Greenland and as that moves towards the Arctic we get very interesting dynamics occurring. To be in thermodynamic equilibrium now, the zonal wind deviations are transferred further down and with the already weakened Tropospheric zonal wind that increases the chances of a major SSW that goes on to affect the surface. It's just one run and only occurs if the split if quick enough to cause a major SSW but it's a very good run and 1 of the possibilities.

Sorry @Kasim Awan just had to do one more, that's pretty much my motto. Will take the week off to recharge (especially after my mocks which I found harder than any recent meteorology documents that I've read lol) now though, see you all either late next week or after the 2010 repeat .

[northwestsnow]

8 minutes ago, jules216 said:

I also mentioned in earlier post about a threat of WB -NAO and "All of the sudden" here is latest GFS anomally, there is also that Portuguese trough doing no one any favors. Its just plain ridiculous to have a lovely Scandi blocking transfering to -NAO but not east based, what has happened to Europe since 2011-12 February that every possible cold spell gets scuppered by something.

We got to keep an eye on developments to our SW Jules ..

All in all though that's a very pleasing anomaly at that timescale 

[jules216]

I was doing my winter analogs on the 08.10.2022 and here how they stack Up against latest GEFs trends. I have explicitly mentioned "unlucky" outcome for Slovakia and blocked Atlantic, so far its going accordingly.

[phil b]

44 minutes ago, I remember Atlantic 252 said:

and here but wet and non settling

Are you sure?  This photo was taken on the 9th 

Edited November 26, 2022 by phil b

[Jackski4]

It’s so great to see this forum bursting with excitement and optimism. Brilliant set of runs this morning, especially that GFS// . Never seen anything like it, simply stunning. 
 

@Eagle Eye take some time off mate, stick to the footie thread, recharge and you’ll feel 100x better. As Kasim said, you’re a reputable member of this community and know so much more than I do, yet I’m 7 years older than you. Hell, atleast I can legally buy alcohol so I win. Take care lad

[I remember Atlantic 252]

3 minutes ago, phil b said:

Are you sure?  This was taken on the 9th 

7th was rubbish because of the 'frontal shield' Aldridge has a better elevation

[bluearmy]

1 hour ago, feb1991blizzard said:

As long as the Greenland high holds that Canadian troughing at bay the uppers will be good by the end of the run.

 

33 minutes ago, northwestsnow said:

That is exactly what coldies want to see.

Vortex removed from Canada/ Greenland..

 

21 minutes ago, jules216 said:

I also mentioned in earlier post about a threat of WB -NAO and "All of the sudden" here is latest GFS anomally, there is also that Portuguese trough doing no one any favors. Its just plain ridiculous to have a lovely Scandi blocking transfering to -NAO but not east based, what has happened to Europe since 2011-12 February that every possible cold spell gets scuppered by something.

We do have to keep abreast of developments over Canada - the retrogressive signal is strong and with the main vortex segment  likely to be absent from the Canadian side, it wouldn’t take much for a west based -NAO to evolve, especially with the trend for any scandi blocking to disappear through week 2.   there are many factors at play though so just a slight concern at the moment for coldies 

Edited November 26, 2022 by bluearmy

[Kasim Awan]

Just now, I remember Atlantic 252 said:

7th was rubbish because of the 'frontal shield' Aldridge has a better elevation

Dont think it was typical wet snow - related to low humidity increasing evaporation of the flake, so the small flakes become small near surface => easily melt in strong feb sun

[jules216]

3 minutes ago, bluearmy said:

 

 

We do have to keep abreast of developments over Canada - the retrogressive signal is strong and with the main vortex segment  likely to be absent from the Canadian side, it wouldn’t take much for a west based -NAO to evolve, especially with the trend for any scandi blocking to disappear through week 2.   there are many factors at play though so just a slight concern at the moment for coldies 

You see and yet my comments come across as pesimistic but I have been proven right many times. Why not even consider those ideas? Some experienced people do agree with me on the fact caution is required. My seasonal analogs since spring this year have Also Been spot on! Check Twitter.

[Paul]

As we seem to have gone off on about 5 different tangents, and we're between runs at the moment, now seems a good time to lock this and open a fresh thread.

New thread here: