Model Output Discussion - New Year and Beyond

[andymusic]

28 minutes ago, MJB said:

Eh?

What output is showing the next 5 weeks at well above average temps?

yep - models can just about cope with 5/7 days - 10 at a real real stretch in certain weather set ups - so 5 weeks is a total no no lol

[Cambrian]

The current modelling into week 2 looks a bit iffy. It’s no big deal if that’s what we get in any case - we have later into February and a good chunk of March still to go before the spring equinox to bring some more seasonal weather, but I’d be reticent to totally write off the chances of cold in early February just yet.

There is quite a bit of highly relevant wriggle room, typified on the day 8 ensemble mean from the 6z GFS. There’s a cross-polar flow from Alaska to Europe, thanks to the linkage of the Siberian and Scandinavian lobes of the PV, and interestingly, the Aleutian and Atlantic heights are doing just enough to prevent merging of the Canadian and Scandinavian lobes. They do merge by day 10 on the 6z GFS run, but the 0z ECM at day 10 still keeps them well apart. 

  

At day 8, a slight thickening of the lower heights through the Kara Sea, where there is a bit of spread, would straighten the cross-polar flow and elongate the Scandinavian trough. The greatest spread, however, is at either end of the Eurasian PV lobe, very much bringing the UK and Ireland into play for the Scandinavian trough with very modest changes. Around Newfoundland, the relatively weak cyclonic development spawned by the Canadian lobe is another area of doubt. This is one of the main factors preventing further retrogression of the Atlantic high. This has been a repeated feature of the spread charts over recent days. The consistent low heights in the Mediterranean also encourages the idea that a tad more retrogression might just be feasible. 

Having said that, overall it does look most likely that the centre of the high will become anchored to our southwest for a fair while, which is supported by the spreads for where the high is located too. 

However, the spreads do also suggest that there is probably a good deal more scope for further polar maritime and/or northerly incursions around its northeastern flank heading into early February than is currently being played out in the ops or ensemble-wide means. 

 

Whatever we get, it’s going to be a good deal better than looking out your window and seeing this like the inhabitants of Bursa, Turkey did a few days ago. I tell you, one look at that and I’d have been clean out of there before you could say kebab, let alone lenticular cloud. 

[Kasim Awan]

Still a solid signal for a mid Atlantic high in the next 7-10 days. Question is whether it can make a decent attempt at ridging northwards alongside a southeasterly push of trough energy into Europe. 

[on the coast]

Look at the brutal cold going into America. Very severe stuff again for them.

[phil nw.]

7 minutes ago, on the coast said:

Look at the brutal cold going into America. Very severe stuff again for them.

Yes the Canadian pv is quite a deep feature showing severe cold and as it rotates around.As you say the main thrust is into NA but some of that spins off towards us but we get the scraps in the UK

The coldest flow  is just a little too far east with the high too close by in the Atlantic.Frustrating  really as we are not a million miles away from returning to more cold- instead just temporary glancing blows for us.

At least the prospect of an immediate switch to a broad and mild south westerly prospect is delayed for now.This coming week it looks like more north westerly at times.Week 2 though,less said at the moment the better i think mmm. 

 

[northwestsnow]

UKMO 168 is close..

[Kasim Awan]

11 minutes ago, northwestsnow said:

UKMO 168 is close..

Imo we're seeing evidence for the Atlantic high to migrate closer to Newfoundland with each northerly attempt. We've already been through a couple of these cycles and had a bite of the cherry. A week of 10cm+ snowcover here now. Another few attempts and another bite seems possible given this retrogression signal.

[minus10]

If i am reading this correct is this not one of Nick Sussex's shortwaves stopping the high from retrogressing and linking north west and thus opening the door to more potent pm's...

 

 

[KTtom]

Well GFS 300 Plus charts were acceptable a couple of weeks ago, so here is tonights, my point being, to back up this mornings post that sometimes patterns are predictable and models do not 'struggle' as much as other times and hence the old term FI moves around timescales..look back through the thread, this is the pattern GFS has rolled out at least for the last 3 runs..it also mirrors the mean from this morning (probably a worst case but the theme is the same)..

 

[tight isobar]

Just a quick 1 (watching the mighty Arsenal)  The gfs 12z notes decidedly close Synoptics- for a tsp in colder upper air out east/ north east!.. the gage for wintery precipitation grows- and the south eastern  quadrant-doesn’t want to let the cold from its grasp... away from the much mentioned upper level ramifications- or otherwise!! I’m watching the nxt 7 days with growing interest!...

 

Edited January 22, 2023 by tight isobar

[northwestsnow]

GEM day 10, perhaps a PM incoming.

[KTtom]

..to add to my negative mood this Sunday evening...the farthest reaches of the gfs backs up what Blue (i think) said this morning of the dangers not having a split...that SPV looks ready to regain control once the series of warmings die out??

[Guest]

49 minutes ago, KTtom said:

Well GFS 300 Plus charts were acceptable a couple of weeks ago, so here is tonights, my point being, to back up this mornings post that sometimes patterns are predictable and models do not 'struggle' as much as other times and hence the old term FI moves around timescales..look back through the thread, this is the pattern GFS has rolled out at least for the last 3 runs..it also mirrors the mean from this morning (probably a worst case but the theme is the same)..

 

Lol, well if it fits the agenda...

I am no fan of cold but the ensembles aren't that mild 

Edited January 22, 2023 by Guest

[Mike Poole]

47 minutes ago, KTtom said:

..to add to my negative mood this Sunday evening...the farthest reaches of the gfs backs up what Blue (i think) said this morning of the dangers not having a split...that SPV looks ready to regain control once the series of warmings die out??

Yep, looks like it.  

Since Friday morning, when about half of GEFS were showing a technical SSW (I called it at the time, teach me to count my chickens!) - that has reduced on every run, to zero now!

Look at the pressure chart for the same time T384:

Not a good position, to put it mildly.  

You just couldn’t make this winter up!  The trop vortex has never let the strat vortex rule the roost, and has been as weak as you’d like, but most of the time conspired to leave us in the mild, and even when it hasn’t there’s no snow, so what’s the point?  Now, the trop blocking has weakened the strat vortex, but not enough, the result being forcing down a renewed burst of westerly winds, you can see it here:

The warming is at the top (yellow), will increase the zonal winds lower down (red arrows), which will probably lead to a reversion to +NAO - as shown in most GFS runs.  And then, get this!, then the warming runs out of steam, leaving the remains of the vortex in a bad place.  Leaves us coldies relying yet again on the MJO when the westerly burst has gone through.  

Sorry about the negative post, in future winters that are like 2019/20 we’ll look back at this one, and ask ‘how could we lose from here?’.  And I offer no explanation other than bad luck…

Edited January 22, 2023 by Mike Poole

[Don]

I'm starting to fear that February could be similar to last year now!

[Don]

2 minutes ago, Mike Poole said:

The warming is at the top (yellow), will increase the zonal winds lower down, which will probably lead to a reversion to +NAO - as shown in most GFS runs.  And then, get this!, then the warming runs out of steam, leaving the remains of the vortex in a bad place.  Leaves us coldies relying yet again on the MJO when the westerly burst has gone through.  

Sorry about the negative post, in future winters that are like 2019/20 we’ll look back at this one, and ask ‘how could we lose from here?’.  And I offer no explanation other than bad luck…

Do you think mid February onwards could deliver a cold spell, Mike?

[Mike Poole]

2 minutes ago, Don said:

Do you think mid February onwards could deliver a cold spell, Mike?

Depends on the MJO making it into favourable phases not the COD, and whether we get anything at all useful downwelling from the strat after the westerlies have gone through.   I’m sure another strat warming event is possible, but that will be too late now, I think.

Edited January 22, 2023 by Mike Poole

[summer blizzard]

Modelling will come to our route. 

[feb1991blizzard]

20 minutes ago, Don said:

Do you think mid February onwards could deliver a cold spell, Mike?

FWIW - i am still confident but it looks pushed back all the time - thinking really now 16th or 17th we'd be doing really well, i'm now edging towards 22nd / 23rd, its got 2018 written all over it.

[That ECM]

3 minutes ago, feb1991blizzard said:

FWIW - i am still confident but it looks pushed back all the time - thinking really now 16th or 17th we'd be doing really well, i'm now edging towards 22nd / 23rd, its got 2018 written all over it.

At this rate it’ll be the 30th.

 

what are you seeing that makes you feel confident about a cold spell? TIA

[Don]

4 minutes ago, feb1991blizzard said:

FWIW - i am still confident but it looks pushed back all the time - thinking really now 16th or 17th we'd be doing really well, i'm now edging towards 22nd / 23rd, its got 2018 written all over it.

Problem is when it keeps getting pushed back, that often spells trouble.  However, I'm glad you're still confident and certainly wouldn't complain if we have a 2018 repeat!

[blizzard81]

Improvement for next weekend hemispherically wise on tonight's ecm compared to yesterday's run. 

1 minute ago, blizzard81 said:

Improvement for next weekend hemispherically wise on tonight's ecm compared to yesterday's run. 

Which leads to this. 

[feb1991blizzard]

12 minutes ago, That ECM said:

At this rate it’ll be the 30th.

 

what are you seeing that makes you feel confident about a cold spell? TIA

The state of the Polar vortex, combined with that MJO plot, it looks ripe for a split SSW at some point.

[Chesil View]

18 minutes ago, feb1991blizzard said:

FWIW - i am still confident but it looks pushed back all the time - thinking really now 16th or 17th we'd be doing really well, i'm now edging towards 22nd / 23rd, its got 2018 written all over it.

Smart money has always been on the second half/final third of Feb for another potent winter burst.

[TSNWK]

5 minutes ago, blizzard81 said:

Improvement for next weekend hemispherically wise on tonight's ecm compared to yesterday's run. 

Which leads to this. 

Looks so primed for a great day 9 chart? Mid atlantic heights intobthe gap between those two lobes of the vortex.. but I guess the low at the base of Canadian lobe will roll across to meets its European cousin and flattern the pattern