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Paul

Hunt For Cold: Model Discussion - Heading Into Christmas

Paul

If you're hunting for cold potential in the model output, this thread is for you. But if you'd like to look more widely at the models, please head over to the general model discussion thread.

This is a model related thread, so a general, frequent theme of the model output is a given, but it will not be strictly enforced:

  • Some topic drift, humorous responses etc are fine
  • Posts likely to lead the thread off on an entirely off topic tangent are not ok. For example (but not solely limited to): Posts entirely or mainly about Met Office, BBC or media forecasts with little or no model context, and posts solely asking for a weather forecast in a specific location.
  • Posts which start with something like 'I know this is off topic but ...' are not ok.
  • Posts which break the forum guidelines are not ok (eg trolling, troll-hunting, weather guilt tripping, overly defensive/aggressive, abusive, disrespectful to others)

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1 hour ago, Purga said:

Well it appears that the initial Trop response is:

 

image.thumb.png.212aaef688e67bd3dc9fb4a61dcaca13.png

You've got to have a sense of humour though it's Christmas! 😆🤶.

 

Well it isn’t really as it’s not reasonable to expect to see a QTR on a model run that doesn’t actually show a reversal (gfs) and the downwelling wave takes around two weeks so would be out of range anyway .....

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10 minutes ago, Easton Luna Boys said:

Exactly. This is a reality check; despite constant predictions of blocking high scenarios bringing cold and snow by some since late November, nothing has materialised. In fact we are now looking at one of the mildest Decembers on record. It just goes to show that despite years of model watching, no one can really predict the weather with any accuracy more than 5 days out. 

Maybe the message for late autumn and early winter was in the SSTs - see my post from Sept 25th -

Quote

The correlations between the north Atlantic area as defined in the charts above and CET are weak, but show that for October, CET is most closely linked to September SST (corr 0.27 from 1950-2017) - would suggest a slightly cooler than average October this year

November and especially December show a negative correlation with May and June (corr -0.22, -0.26 and -0.3, -0.29) which would lead to a milder late autumn and early winter

The area-weighted average May-June SST this year was 9.874°C - about the same as the average of the 12 other coldest years (9.883°C) - the average CET in the following Decembers was 6.08°C. Interestingly, as well as the coldest May-June SST (since 1950) in 2015 being followed by the record warmest December (9.7°C), the second coldest SST in 1974 was followed by the overall joint second warmest December (8.1°C). There are 5 more 6+ degree Decembers in these 12 years and only one below average (2009).

CET anomalies, October 0.0, November +1.8, December (to the 18th) +1.9 at 6.8°C

Looking like quite a good call.

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Of all the outputs the GFS shows at least some possibility of improving .

The key thing is whether there’s any chance of some better trough disruption , some energy needs to split and head towards Iberia around day 5 and day 6 .

Even after that the location of the PV to the east and more digging trough to the west does allow for something to happen in the middle !

If the Euros weren’t so dire I’d be a bit more encouraged given the GFS trend . Anyway we’ll see tonight if there’s any more mileage .

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The output really could be far worse, the Euro has high pressure firmly in control which is better than monster lows moving through the UK. 

ECMOPEU00_240_1.png

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The problem with just waiting and expecting things to magically change in 10 days is the troposphere effects what happens in the strat. If we keep seeing this completely flat pattern in the Atlantic then that is a big absence of a key tropospheric precursor of wave-2. We can see this in the GFS, especially the OP where it refuses to split the vortex after displacement. So yes there is every reason to worry because If We don't get a split the likelihood is we will just have a small window of opportunity after displacement and then the vortex will be fit and healthy again a couple of weeks later.

Edited by Snowy L

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5 minutes ago, Snowy L said:

The problem with just waiting and expecting things to magically change in 10 days is the troposphere effects what happens in the strat. If we keep seeing this completely flat pattern in the Atlantic then that is a big absence of a key tropospheric precursor of wave-2. We can see this in the GFS, especially the OP where it refuses to split the vortex after displacement. So yes there is every reason to worry because If We don't get a split the likelihood is we will just have a small window of opportunity after displacement and then the vortex will be fit and healthy again a couple of weeks later.

I agree, esp the part about the Atlantic!

6z just about showing signs of a slowing down into FI perhaps..

Edited by northwestsnow

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3 minutes ago, Snowy L said:

The problem with just waiting and expecting things to magically change in 10 days is the troposphere effects what happens in the strat. If we keep seeing this completely flat pattern in the Atlantic then that is a big absence of a key tropospheric precursor of wave-2. We can see this in the GFS, especially the OP where it refuses to split the vortex after displacement. So yes there is every reason to worry because If We don't get a split the likelihood is we will just have a small window of opportunity after displacement and then the vortex will be fit and healthy again a couple of weeks later.

Indeed, we had our amplified period in the atlantic recently and didn’t get much reward for it to be honest. The euroslug continues to dominate proceedings and until we get any stratospheric effects we are unfortunately stuck

Still... let’s be positive everyone SSW happening and 2/3’rds of winter left, I remember some of the charts from winters past, trust me we are infinitely better off even with this Iberian slug

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17 minutes ago, bluearmy said:

Quite a lot of odd posts on here this morning - in the famous words of mr b fawlty. - ‘what did you expect to see from a Torquay hotel window’ ............

no one has been touting the ‘hanging gardens of Babylon’ so why some are expecting to see them is quite odd

what is currently showing is that the ecm spreads can often be a better tool than the ecm clusters in the 7/10 day period - the upper ridge looks to be a little more suppressed than was showing a few days ago with the jet running across to our north 

Your last paragraph sums up why people on here are despondent this morning. Very flat output today. 

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6Z going the same way as 00z - raging +NAO - euro heights/ strong PV..

EC while not great is fabulous compared to gfs.

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1 minute ago, blizzard81 said:

Happy New Year! Deary me. 

gfsnh-0-300.png

However, given that we shouldn't be expecting any troposphere impact of the SSW until at least mid to late January, it's not unlikely that we' see charts like this.

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2 minutes ago, blizzard81 said:

Happy New Year! Deary me. 

gfsnh-0-300.png

Pretty rubbish, im Looking at GEFS rather than this, hoping a gradual increase in better NH profiles. The last few runs have had 6/7 block scenarios, let’s see where we go on this one.

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2 hours ago, northwestsnow said:

TBH  i think coldies need to hold their nerve at the moment..

I fully understand the frustration but team Joe is right, its January that holds most interest..

Will be interesting to see Mikes zonal winds chart, hopefully the signal for the drop/reversal is still there..

 

 

Here's the GEFS zonal wind chart, 4th day running every single member shows technical SSW - none of them even marginal. 

u_60N_10hpa_gefs.thumb.png.885d8ed882702cb5ab33d701b5ffac17.png

So it does make me wonder what it is that is causing such inconsistency from the op runs over the same sort of timescale.  Just have to wait and see, I guess.

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19 minutes ago, Snowy L said:

The problem with just waiting and expecting things to magically change in 10 days is the troposphere effects what happens in the strat. If we keep seeing this completely flat pattern in the Atlantic then that is a big absence of a key tropospheric precursor of wave-2. We can see this in the GFS, especially the OP where it refuses to split the vortex after displacement. So yes there is every reason to worry because If We don't get a split the likelihood is we will just have a small window of opportunity after displacement and then the vortex will be fit and healthy again a couple of weeks later.

At 240h EC and GFS don't make a great difference. And EC this morning had a split https://twitter.com/TradeWpower/status/1075668727683842050

ECMOPNH00_240_1.png

GFSOPNH06_240_1.png

5c1b6dbc3459b.jpg

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Even the comments in the strat thread are a bit more downbeat this morning. 

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1 minute ago, Mike Poole said:

Here's the GEFS zonal wind chart, 4th day running every single member shows technical SSW - none of them even marginal. 

u_60N_10hpa_gefs.thumb.png.885d8ed882702cb5ab33d701b5ffac17.png

So it does make me wonder what it is that is causing such inconsistency from the op runs over the same sort of timescale.  Just have to wait and see, I guess.

Yes thats still looking good thanks Mike 🙂

 

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1 minute ago, Mike Poole said:

Here's the GEFS zonal wind chart, 4th day running every single member shows technical SSW - none of them even marginal. 

u_60N_10hpa_gefs.thumb.png.885d8ed882702cb5ab33d701b5ffac17.png

So it does make me wonder what it is that is causing such inconsistency from the op runs over the same sort of timescale.  Just have to wait and see, I guess.

Amy Butler tweeted this:  

 

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Not the first 06Z run, that's shown raging zonality, at T+384? Cold is proving a very elusive prey!:help:

Netweather GFS Image

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2 minutes ago, sebastiaan1973 said:

At 240h EC and GFS don't make a great difference. And EC this morning had a split https://twitter.com/TradeWpower/status/1075668727683842050

ECMOPNH00_240_1.png

GFSOPNH06_240_1.png

5c1b6dbc3459b.jpg

Again, thanks for this Sebastiaan , EC still going for a split, GFS not so keen..

The plot thickens ..

 

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