Model Output Discussion 29th December - Into mid-Winter.

[Mucka]

Another very poor UKMO

[Seasonality]

3 hours ago, radiohead said:

There isn't a huge difference between the 4 runs and at times the 06Z or 18Z will score better than the midday and midnight runs. So it's very silly to dismiss the 06Z and 18Z.

However. I have learned that while there is no difference in the southern hemisphere, NCEP have (previously at least) noticed that the 06Z and 18Z tend to score a little worse in the Northern Hemisphere. There is a PowerPoint presentation about it, I can't remember exactly where I found it or what year it is from though.

Indeed. Maybe small differences but not enough to dismiss them out of hand. That is one of many bits of forum myth wisdom that have established themselves as fact.

[jvenge]

EPS 46 weekly showing a mild output for all of Europe, as a mean, after 14 days or so. Of course, considering the near term output changes and the fact you'd need to study the member clusters to figure out how that mean comes, it would be best not to slash your wrists just yet.

Edited January 13, 2017 by jvenge

[KTtom]

Blimey, you have to be honest and say if the UKMO trend continues next week's easterly will quickly become a westerly !

 

 

[Severe Siberian icy blast]

2 minutes ago, jvenge said:

EPS 46 weekly showing a mild January for all of Europe, as a mean, after 14 days or so. Of course, considering the near term output changes and the fact you'd need to study the member clusters to figure out how that mean comes, it would be best not to slash your wrists just yet.

The next 14 days will take us into February my friend? Or there abouts.

The ec monthly is setting high pressure up toward Greenland area with some kind of NAO setting up. Which is a great outlook but none of the long range modles have done great this year so who knows!

[jvenge]

GEFS showing a little more agreement to T144 than they have for quite a few days. Of course, that could just mean they are all wrong ;-).

[mb018538]

The ensembles aren't looking as good as they did either:



The mean is now above -5c....though this is skewed by the marked outcome differences at the 17th January, with a mild vs colder split. Looks like this is the key time now. The 00z MetO run looks like it's trending towards the 'milder' outcome this morning too.

[winterof79]

Westerlies?Not any time soon

Ice Ice Baby

 

 

Cold for the reliable

 

 

Edited January 13, 2017 by winterof79

[IDO]

Quite interesting setup; all models showing around a 5 day wave from the Azores (From D3) and they are struggling with how that interacts with PV, which is on the march from Canada to Siberia at the same time. In the last couple of days the trend has been to prevent a ridge to Scandinavia building far enough north for a Scandi High, that looks a bust, but the models handle this differently, thgough GFS and ECM edging towrads a consensus. The GFS sustains a ridge towards Scandi with the surface high in the northern Europe mainland. At around D8 that high has merged with the Siberian/Russian High and is cut off from the ridge and eases east:

GFS D6  GFS D8

Leaving the residue Azores heights in the Atlantic and the S. Euro trough is more instructive for the UK. So a cold setup for the SE on this run for at least 10 days. The GEM again just blows up a UK high with the energy from the Azores:

GEM D6

Pretty average temp wise I would expect. UKMO at D6 looking that way.

ECM has the ridge just a bit further south than the GFS. It also initially does not connect the high to the Russian high, so by D8 the high is cut off from the UK in eastern Europe, with a pocket cut off to the NEE (a la GFS op), with the UK influenced more by the trough to the south; not dissimilar surface conditions as to the GFS op. 

D5 ECM  D8 

The GEFS support the pattern that the GFS op shows but vary within that theme.

A very messy mix with a quasi-blocked Atlantic and low heights in southern Europe. Initially next week a slack Easterly rather than a continental flow is probably favourite for the SE GFS/ECM solution). So dry up to around D8-9. Once the wave dies there is little forcing so at D12 the PV lobe has migrated to the Siberian side. From there the GEFS show no coherence as to where the PV next stop is though the mean hints at a return ticket to Canada again (this cycling a theme). ATM that 11-16 day period looks like a quiet period where there is a holding pattern, but there is potential around D9 so that range just guesswork at the moment.

[carinthian]

GFS and ECM latest both showing a relocation of the main high pressure to the NW of the British Isles at day 10. This should prolong the colder spell for many with a risk of some snow to the SW of England where the upper temps will be the lowest.

 C

[mb018538]

As above....ECM reloads everything to the north instead, and also joins the club in not sending the cold air our way. So it now looks like just a cold high, with some chilly days and frosty nights. Nice height rises to the NW by day 9/10, with cold air never far away. One to keep an eye on.

[bluearmy]

eps in that 9/12 day period remain important - will they continue to head towards west based neg NAO with mildest  sou'wester across nw Europe or can we get some features established in that few days which will put the northern arm on a different track. 

[Severe Siberian icy blast]

 Great looking charts moving forward with another northerly of sorts becoming a possibility around day 8?

Edited January 13, 2017 by Polar Maritime
To move discussion on..

[Faronstream]

ECM 0Z this night continues to show the trend of a more mid latitude blocking than high latitude blocking for the mid parts of next week, if the centre of the high pressure would just move slightly up to the western parts of russia/Finland  the easterlies would be stronger and much lower 850hpa, looks like we fell on the finish line again..

[mb018538]

What's also interesting going forward is this:

Notice the complete lack of cold air on the eastern seaboard and even the bulk of Canada. Last winter, for example, we had endless amounts of cold air pouring off the east coast of North America...net result massive temperature contrasts with warmer tropical air from the south, and a raging jet stream and deep low pressure systems. There has been a general absence of this through the winter so far, and it looks like continuing for a while yet. Incidentally it would appear most of the cold air locked away in the PV is spilling out over the other side of the globe in the next week.

[jvenge]

17 minutes ago, Faronstream said:

ECM 0Z this night continues to show the trend of a more mid latitude blocking than high latitude blocking for the mid parts of next week, if the centre of the high pressure would just move slightly up to the western parts of russia/Finland  the easterlies would be stronger and much lower 850hpa, looks like we fell on the finish line again..

South East will still be a little below average and some frosts, but yes, it looks like the colder air is pushing into France and Spain (not often you get to say that!). 

[Gavin Hannah]

Next Wednesday - notice how intense Greenland HP is

 

Then, by Saturday

 

Hp to our NW and a slack Greenland. If i'm not mistaken, that's a great opportunity for a 'fabled' Greenie HP, if the dice fall the right way. I know it's just one run, but it seems the trend is definitely for Greenland to go slack towards next weekend. Something I don't recall seeing at all last winter.

 

 

Edited January 13, 2017 by Gavin Hannah

[carinthian]

43 minutes ago, carinthian said:

GFS and ECM latest both showing a relocation of the main high pressure to the NW of the British Isles at day 10. This should prolong the colder spell for many with a risk of some snow to the SW of England where the upper temps will be the lowest.

 C

Its going to feel very cold in the south on Thursday with DAM 528 level close by, cold enough to produce some snow in places, especially the SW where the DP temps will be lowest in the region of -5c values.

 C

[mb018538]

That 'Greenland high' on the 120 chart posted isn't a 'real' Greenland high. Heights far too low! Need those oranges and yellows to be in the area:



Something like this would be great!

[nick sussex]

They should rename the UKMO to the UKMM, the UK Misery Model. Its really the worst solution out of the big 3 and although the high can't sink its least likely to bring the colder air further north into the UK.

Looking at its T84hrs fax chart that's an improvement from last nights T96hrs with the reverse cold front moving sw, its hard to know whether they've modified that because we don't get 12hr steps forward but the milder air seems to be making slower progress eastwards.

Putting that aside both the ECM and GFS are similar in trend, they develop a lobe of high pressure to the nw but we do see the west negative NAO begin to rear its ugly head. That's still a long way off and might change, hopefully!

[joggs]

23 minutes ago, Gavin Hannah said:

Next Wednesday - notice how intense Greenland HP is

 

Then, by Saturday

 

Hp to our NW and a slack Greenland. If i'm not mistaken, that's a great opportunity for a 'fabled' Greenie HP, if the dice fall the right way. I know it's just one run, but it seems the trend is definitely for Greenland to go slack towards next weekend. Something I don't recall seeing at all last winter.

 

 

Sorry that's not a Greenland hp.

You need orangey yellows on them charts.

Edited January 13, 2017 by joggs

[Gavin Hannah]

2 minutes ago, joggs said:

Sorry that's not a Greenland hp.

You need orangey yellows on themy charts.

The charts I posted are the 850s, this is the 500.  The blob of yellow and orange needs to be tad further north though. My point is, it's got potential.

 

 

 

 

[MR EXTREMES]

Clarity on Sundays runs I reckon still few little bits to iron out the lack of Atlantic domination is always a positive.

Things have back tracked a bit but still feel either retrograde to Greenland or another lobe moving in around Greenland. 

Upgrades look more likely than not things just bit messy right now.

[Gavin Hannah]

1 minute ago, MR EXTREMES said:

Clarity on Sundays runs I reckon still few little bits to iron out the lack of Atlantic domination is always a positive.

Things have back tracked a bit but still feel either retrograde to Greenland or another lobe moving in around Greenland. 

Upgrades look more likely than not things just bit messy right now.

 

We are in a far better position compared with last year. Ok Decmeber was a let down, how things have change quickly this past week. Oddles of potential coming up, and all it takes is a gentle nudge from the weather gods in the right direction.

[Frostbite1980]

CFS daily has produced an interesting run with plenty of boarderline snow opportunities over the next couple of weeks lol