Model Output Discussion - Into February

[BLAST FROM THE PAST]

Just now, Lukesluckybunch said:

yes takes virtually the whole of the PV from the west to east..but what about that low or perhaps it wont be like that come that point

Perhaps it won’t….but now you see it.  Let’s just refer to the run….it’s coldie perfection setting up.  Now it just needs to verify down the line.

 

BFTP

[Lukesluckybunch]

1 minute ago, BLAST FROM THE PAST said:

Perhaps it won’t….but now you see it.  Let’s just refer to the run….it’s coldie perfection setting up.  Now it just needs to verify down the line.

 

BFTP

yes not often we see charts that good!

[Allseasons-Si]

@Mark wheeler,...here you go mate,...the infamous NAVGEM at just 180

[Tim Bland]

ECM & GFS @ Day 10 .. Fairly good agreement there 

[January Snowstorm]

15 minutes ago, Allseasons-si said:

@Mark wheeler,...here you go mate,...the infamous NAVGEM at just 180

Wow, Sat 18th and we have lift off!

The upgrades are coming now and at long last the models are smelling the daisies!!

[Allseasons-Si]

Pretty good mean at day ten...

now where will it go from here,...the fun starts from day ten and it will be interesting over the next few days to see if these NW heights have traction.

[Notty]

1 hour ago, Mike Poole said:

GFS control is an absolute ripsnorter in FI, T192 onwards:

Yes please

[Mike Poole]

ECM clusters have gone full tonto!

That signal I was watching for retrogression on the last 3 updates?  Well, this time the ECM ensembles have thrown the kitchen sink at it!

T264+:

It’s either the ECM/GFS solution with 35 members, or a rather unconvincing watered down version with 16. 

T192-T240:

There’s some uncertainty hence the five clusters, but significant blocking is there by T240 on all 5 clusters, potential is massive from there, as the later timeframe plot has indeed shown.

 

Edited February 18, 2023 by Mike Poole

[Catacol]

22 hours ago, Met4Cast said:

This is perhaps a discussion for elsewhere, it's a shame there's no longer a technical model output thread as this could be a very interesting & I'm sure quite long discussion/debate! 

There is some suggestion that RMM MJO plots & indeed their corresponding composites include the lag within the outputs to some extent, I'm not sure I agree on the 10-25 days point. The MJO has been transitioning through phase 6 which does support Atlantic riding and indeed that's what we're currently expecting to see next week. High pressure in the Atlantic but not enough oomph to get it up into Greenland. Composites are rough guides so the phase 6 La Nina composite isn't an exact match, but I think it's close enough to suggest next weeks Atlantic ridging is a result of the phase 6 transition. 

HP to the west, low pressure to the east. Anomalies on the composite there are far more extreme than what is being modelled for next week but I think it provides a broad picture which does match with current NWP modelling. 

The MJO is of course tied into the GWO & overall momentum budget, these aren't separate things but consolidated, i.e MJO moving west leads to rising AAM via +ve frictional torque processes. Indeed we're seeing that being represented now with a rise in AAM in recent days as the MJO transitions through the Pacific with a sharp rise in +EAMT now too.

Broadly speaking rising GLAAM signals increasing westerly momentum within the overall budget leading to an increasingly disturbed jet stream & subsequently increasing support for high-lat blocking somewhere down the line.

What we're seeing next week then I would argue was predictable using this method and given only modest rise in GLAAM so far and the continued strong Canadian Vortex, next week was never going to deliver blocking into Greenland, but an Atlantic toppler was the favoured outcome. 

My post was specifically talking about next week rather than February as a whole & agree with your conclusion that the lack of cold this February has been down to the MJO but also the continued anti-cylonic wave breaking into Europe keeping high pressure dominating, this again largely down to what's going on in the sub-tropics. 

Using the above method & taking into account lag effects, the AAM in theory should continue rising although probably not to a significant amplitude as the broader GWO remains in a very low amplitude phase 4, MJO transitioning into phase 7 combined with potential downwelling (jury is still out on this) from the SSW comes together to increase the chances of blocking into higher latitudes come early March. Without the SSW imprinting onto the troposphere and draining the TPV to the Asian side though I do wonder if trop-led developments alone will be enough to give everyone here what they want, my instinct says probably not. 

P.S forgive me, I am still in the infancy of trying to learn this stuff and I don't think i'd even class myself as a novice yet, but this is my very basic understanding on the situation re: teleconnections.

In terms of MJO lag time, something I have wrestled with for a long time, this article is interesting. It is focused primarily on MJO impacts over North America but on p1755 and 1757 there is a cluster analysis that includes -NAO via Greenland ridging and the lag time impacts of phase 6 and 7 suggest a much longer lag than I was previously aware. The transitions in November and January this season I would suggest bear out the conclusions within it. Impacts of phase 6 and 7 yet to be felt.

Just a moment...

WWW.RESEARCHGATE.NET

 

[Methuselah]

9 minutes ago, January Snowstorm said:

Wow, Sat 18th and we have lift off!

The upgrades are coming now and at long last the models are smelling the daisies!!

Well, let us hope the overnight model runs don't smell the sheet, eh? 

[January Snowstorm]

Whatever happened Chino, the mastermind of the strat? I can't remember last time he posted...

[Ali1977]

8 minutes ago, Mike Poole said:

ECM clusters have gone full tonto!

That signal I was watching for retrogression on the last 3 updates?  Well, this time the ECM ensembles have thrown the kitchen sink at it!

T264+:

It’s either the ECM/GFS solution with 35 members, or a rather unconvincing watered down version with 16. 

T192-T240, there’s more uncertainty, but significant blocking is there by T240 on all 5 clusters, potential massive from there, as the later timeframe plot shows:

 

Get in, that’s what we want Mike

Edited February 18, 2023 by Ali1977

[Stuie]

Haven`t read earlier posts but for 7 days time, the `big` three 850`s.

[alexisj9]

40 minutes ago, Lukesluckybunch said:

but how do you know this...becasue that low out to the southwest looks as though it may just flatten the high..leaving us in southeast or south winds,thats the threat im seeing but i hope i am wrong

Looks like it will go under and join the low to the south to me, which would push the high up.

[Lukesluckybunch]

10 minutes ago, alexisj9 said:

Looks like it will go under and join the low to the south to me, which would push the high up.

not so sure...doesnt look like a slider to me...

[Lukesluckybunch]

18 minutes ago, Stuie said:

Haven`t read earlier posts but for 7 days time, the `big` three 850`s.

gfs probably the best with them heights stretching right up!

[BLAST FROM THE PAST]

7 minutes ago, Lukesluckybunch said:

not so sure...doesnt look like a slider to me...

ECM leads to one outcome, and that LP at t240 to SW will go into France

 BFTP

[alexisj9]

6 minutes ago, Lukesluckybunch said:

not so sure...doesnt look like a slider to me...

It does look round, but the high if you look to the north, is already on top of it, high won't be pushed down. Plus, the low coming down to our north, won't let it push east either.

[Paul White.]

1 hour ago, Purga said:

A lack lustre ECM D10 with a benign easterly, maybe chilly but far from wintry at this stage. In danger of sinking SE leaving the UK in SSE or eventiually SSW flow.

I think you are in danger of gaining a reputation of being negative. To me the chart looks like it will join with the heights to the west and go on a jolly to Greenland. See isn’t it nice to write an optimistic post. You should try it

[Gregulator]

Just a quick question....... do you generally add 10 degrees to those 850 temps for a temp at ground level?.

[Lukesluckybunch]

3 minutes ago, Gregulator said:

Just a quick question....... do you generally add 10 degrees to those 850 temps for a temp at ground level?.

yes thats what many have said

[Buzz]

8 minutes ago, Gregulator said:

Just a quick question....... do you generally add 10 degrees to those 850 temps for a temp at ground level?.

Yes - it's not 100% accurate of course because you need to also factor in other weather variables but it's reasonable as a rough guide.

[stodge]

Evening All

Justifiable interest now as a pattern change seems to be coming into view.

After a brief NW'ly midweek heights will build through the British Isles into Scandinavia through the end of next week into the weekend.

From there? Who knows? Some have suggested a benign SE'ly or even S'ly air flow - maybe - it seems more likely heights will extend west and north west toward Greenland. GFS OP does this but it's all too quick and we end up with a West-based negative NAO and that's always a possibility. GFS Control is much better for cold fans with the trough setting up nearer the British Isles and  very potent N'ly for the first week of March.

The continuing fragmentation of the PV suggests no quick return to the usual pattern and we'll just have to see if we can sustain the colder conditions for more than a fortnight - even if we don't initially, the likelihood of northern heights will continue to keep colder synoptics in play.

Edited February 18, 2023 by stodge

[damianslaw]

ECM, UKMO and GFS all in strong agreement out to 144hrs, rare can say this! High pressure ridging west, a colder northerly flow briefly then heights collapsing into the UK pulling in an easterly - chilly at the surface only, no cold air to tap into, importantly though we see low pressure build to the south/south west.

Thereafter, gosh, I was not expecting the ECM evolution this evening and it seems to be going to the same way as the GFS, it has retrogression all over it.. GFS shows the classic path to a negative NAO/AO combo thanks to the PV migrating to Siberia, heights build rapidly over Greenland and heights have an easy time of linking with these, hence we end with a very cold unstable NE flow.

I'm not clear whether the models at latching onto the effects of the lag of MJO from phase 6 to phase 7, they look very nino esque rather than nina esque, indeed similiar to early December, its seems a little early for the effects of the SSW to downwell, but it would set us up to a possibly sustained period of high lattitude blocking once they kick in.

All very interesting, most interesting place we have been in since late Nov for anyone looking for cold wintry weather, and early-mid March can certainly deliver winter goods every bit as cold and snowy as in Dec-Feb.

[nick sussex]

We certainly don’t want a west based negative NAO.

After all this waiting for the SSW it would be the final insult.

The signal for the high to retrogress does seem to be strengthening so let’s hope it can set up favourably .

Edited February 18, 2023 by nick sussex