Model Output Discussion Autumn 2024

[Mcconnor8]

WXCharts v1.0.22

WWW.WXCHARTS.COM

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ECM loads earlier on here 

[sheikhy]

 TSNWK

WXCharts v1.0.22

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 northwestsnow

WXCharts v1.0.22

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 Gowon

WXCharts v1.0.22

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[AO-]

Perhaps EC is not great, but still a sign of a Southerly jet, which would lead to -NAO. A great starting point in any year. 

Edit: note the tiny shortwave that is about to dive Southeast into Europe and the WAA on the West Side of the hp. Jet heading Southeast as well

Edited November 7 by AO-

[That ECM]

No need to go T240 when T192 for gfs and ecm is as shown. At T168 you could argue that ecm is odd one out wrt the high towards America. It’s an interesting watch but I think no more than that for now. 

Edited November 7 by That ECM

[Kasim Awan]

Just need one push of continental air into Europe. Following this, any sustained high pressure will produce cold surface temperatures.

[AO-]

T240 not really what I expected. The orientation of the shortwaves altered. Very odd imo. Ship hasn't sailed though, but the charts could have been better.

Edited November 7 by AO-

[Nick2373]

Im not convinced with 12z it’s over cooking those temperatures I think we will see a swing back to just above average tomorrow on the 00z

[blizzard81]

It was almost inevitable that the ECM would be the party pooper. 

[KTtom]

 AO- At least Scandinavia looks like starting its winter, Finland is currently around a month behind where it should be.

[AO-]

To explain my previous post: compare tonights EC to the AIFS06. Similar pattern, different evolution. 

[blizzard81]

I remember when the gfs used to be the king of Greenie highs - in terms of modelling them. Don't think it has been these last few years though.

[blizzard81]

The ECM day 10 mean is more toppleresque than this morning's.

[AO-]

Well, nothing really changed since this morning when looking at the EPS. No direction of travel is visible. Temperatures probably below average from Tuesday onwards... No Arctic airmass visible. 

[AO-]

 blizzard81

On the other hand the lobes of the Vortex seem less explicit. Besides pressure over the European continent is lower. Not sure whether it is a downgrade. 

Edited November 7 by AO-

[bluearmy]

Ec 46 trending slightly more Eurasian spv displacement and the graph of the individual members is much more spread than it was a few days ago as we head through December 

the model also sees the defined ridge trough for week 2 now. To be fair, it’s been evident for that week for quite a while but the higher heights were spread to our south up until now 

 

[Mike Poole]

The signal for a northerly seems to have strengthened on the clusters in the T192-T240 timeframe, with cluster 1 (17 members) going for a pretty strong height rise into Greenland.  This morning there were 13 members in the two clusters that showed something similar.  And you can maybe add cluster 4 this evening with a strong Atlantic ridge.

[CoventryWeather]

2 charts.

1) Hovmoller now increasingly colder from around the 17th, has been changing a little lately though. Seems overall good agreement for a colder spell just after mid month. 

2) Zonal winds have significantly declined tonight, mainly around average and a significant amount way below average into December. Certainly the chance that the blocking into Greenland later this month could impact the PV and increase the chance of a SSW. 

[blizzard81]

 CoventryWeather You beat me to it with the zonal winds. Certainly a nice trend that is gaining momentum these last couple of days.

[Mike Poole]

 CoventryWeather Really interesting, that period that was forecast with massively above average zonal winds just looks like it won’t happen at all now, it has been downgraded slightly day by day for about 5 days now until we are now seeing an ensemble where everything is back on the table including a December SSW, with the mean close to climate average.

[AO-]

At least the AIFS is consistent at day10

[CoventryWeather]

 AO- consistently showing a zonal pattern after that - can't see it happening though. Most likely a persistent block to the NW and Scandi troughing...

[AO-]

 CoventryWeather

True. Best not to watch charts over the weekend (and Monday as well). Hope the colder options gain momentum. 

[Thundery wintry showers]

 HarvSlugger I was thinking the same regarding tonight's GFS 12Z run - spot the difference!

The GFS has a long-standing habit of overdoing northerlies at the extended time range so this is very much towards the cold/snowy extreme of the range of possibilities. I see us transitioning from the current anticyclonic weather towards a mild and unsettled westerly type into December, but during that transition high pressure is set to drift out to the west giving a window of opportunity for northerly outbreaks. As Nick Finnis mentioned in his preliminary forecast analysis, transitioning into La Nina often sees a relative emphasis on north-westerly winds in December before turning more westerly in Jan/Feb, so that window could potentially be fairly long, although there is no guarantee that northerlies sourced from high latitudes will necessarily catch the British Isles head-on.

[matty40s]

Nothing to be sniffed at...19th...

[WYorksWeather]

 Mike Poole Thanks for posting these - saved me the trouble. Agree that day 8-10 is worth watching - I often find that's the point where FI craziness starts to downgrade on contact with reality, so encouraging to see a bit of an increase in support. Admittedly a fair way to go yet.

In the extended range beyond day 10, still some interest here as well. Clusters 3 and 5, which collectively make up about a third of the ensemble, both have options for northerly outbreaks. The others are fairly westerly.

GFS 18z to come in the next hour or so, will be interesting to see if it continues in the same vein as the 12z.