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

[Sweatyman]

2 minutes ago, radiohead said:

With -16 uppers poking into Greece....

 

Bet we would be absolutely freezing under that high. Any body post any temps?

[blizzard81]

6 minutes ago, bluearmy said:

There  is but it's painfully slow and will be weak compared to the previous run. Rather closer to the ECM script I think although I expect it has the split flow a bit lopsided later on

The easterly is to our south. High on top of us. Maybe the meto are bang on with their outlook.

[mountain shadow]

2 minutes ago, radiohead said:

With -16 uppers poking into Greece....

 

Whilst we endlessly search for a Greenland High, the Greeks love a UK one.

[johnholmes]

1 hour ago, knocker said:

Tonight's anomalies are more or less on the same page if differing in precise details.

Upstream some differences on the orientation of the Aleutian ridge but okay with the Canadian vortex and north American cold trough. Downstream the Atlantic fairly well amplified but differences exist on the orientation and intensity of the Atlantic ridge which will naturally have a knock on effect on the surface evolution. Certainly we will be looking at some transient wintry weather as systems swing south east around the ridge but the details of this will need to wait until a more definitive position of the ridge has been ascertained

The 10-15 period sees the vortex more organized with a trough in the western Atlantic, the GEFS not quite so keen on this with less ridging over the UK keeps the Atlantic upper flow flatter and more westerly than the more amplified NOAA and EPS. Essentially we are looking at a surface high over or adjacent to the UK for the period portending a dry interlude with temps a little below average but probably quite a diurnal variation. The only fly in the ointment may be the UK high diminishing late on the positive anomalies developing over Iceland and with the trough to our SE this leaves the door ajar to various interpretations

Of course at 8-14 days the 500mb NOAA anomaly may not verify but it will be unusual if the upper flow is not somewhere near to its prediction.

Not sure why you seem concerned at what it shows K because it is probably about the best 8-14 day NOAA chart for blocking I have seen for a long time.Granted the height at 558 DM is nothing special but showing an upper centre, at this range, to be over/near Iceland is one of the best. Also the actual contour flow into and over the UK is fairly light. Very dependent on just where the surface high settles but it will not be moving much I would suggest and very cold air filtering down on its eastern side. A pretty interesting chart to watch IF this does develop. Cold more or less guanteed from the start of the New Year for 2 weeks, albeit with sy=ubtle changes in degree over the following 2 weeks perhaps?

 

Edited December 29, 2016 by johnholmes
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[radiohead]

1 minute ago, Sweatyman said:

Bet we would be absolutely freezing under that high. Any body post any temps?

[cheese]

Just now, mountain shadow said:

Whilst we endlessly search for a Greenland High, the Greeks love a UK one.

I doubt it.. Greece's good weather is one of its few selling points right now. The last thing Athens needs is a blanket of snow driving away northern Europeans looking for some warmth! 

But yes, I'm sure we'd see some very cold nights under that high. Similar to what we've been seeing recently.

[swfc]

late in fi the atlantic is totally blocked and greece freezes!!!

[Bolton67]

3 minutes ago, blizzard81 said:

I do feel the 18z will be not too far off the mark to be honest. Would be typical as the 18z is usually fit for the bin.

Seriously why ?? 

Very OTT post.  You seriously think the latter stages of deep Fi will verify????

[kumquat]

Very cold, very frosty and very dry. Snow for some. Nice 18z. And this within 4 days. I'll take it.

[Singularity]

 

Ironically there's both a weaker jet and a less sharp ridge upstream. A bit contradictory but this is a split jet situation the models are trying to get to grips with after all - notoriously tricky for them to pin down. In fact I've been impressed by the willingness of GFS to consider how the southern arm of the jet might come into play, albeit only intermittently on the det. runs.

For what it's worth, I believe the 18z places things too much 'in the balance' for the inherent bias toward the northern jet arm to be subdued this time around. It's GFS sniffing at the ECM way forward but not committing strongly enough to overcome it's own foibles. Just my opinion, mind.

However - historical cases and as BA has recently conveyed the 12z EPS suggest we should not be all that surprised if the main thrust of the easterly ends up to our south and we experience 'fringe' conditions which tend to be more notably cold at the surface than at the 850's level... limiting wintry shower activity, hence the historical predominance of dry over snowy easterlies for much of the UK (and even in the southeast it's a bit hit-and-miss).

Either way though, we'll have a great setup for a wave-2 assault on the stratospheric vortex;

 

The 12z happened to have better poleward ridges all-round (not just to our NE) so it was a particularly good run as far as the wave-2 attack is concerned.

Having said all that, this potential for early-mid Jan is by far the most tangible so I'm willing to play for it i.e. my sense of belief that something notable could transpire has lifted itself off the floor. No details on timing or snow amounts though!

[Zakos]

A lot of focus on the long range output. Though it is very promising, I do believe we could see widespread snow from this second northerly.

Comparing the ECM and GFS at 192, looks like enough uncertainty remains for widespread snowfall to potentially be a threat?

Certainly looks like it may be more potent that the first northerly

 

 

Edited December 29, 2016 by Zakos

[Scandinavian High.]

Not a done yet with that high push the high north we go in to a easterly more changes to come .

Edited December 29, 2016 by abbie123

[radiohead]

Accumulated snow by T384. Even Crete gets a blanket of a few cm....

It will be interesting to see if there is a trend towards a UK high on the 18Z GEFS.

[booferking]

Just now, radiohead said:

Accumulated snow by T384. Even Crete gets a blanket of a few cm....

It will be interesting to see if there is a trend towards a UK high on the 18Z GEFS.

The northerly also delivers the north of the country with modest amounts of snow and thats the 6th Jan.

[Seasonality]

8 minutes ago, Sweatyman said:

Bet we would be absolutely freezing under that high. Any body post any temps?

Cold for continental Europe for sure. Nothing exceptional but certainly pleasantly cold.

[Banbury]

Control heading in the right way

[blizzard81]

9 minutes ago, Bolton67 said:

Seriously why ?? 

Very OTT post.  You seriously think the latter stages of deep Fi will verify????

I am talking medium term, first 10 days of Jan - high likely to be centred over the UK and easterly running to our south through France. A near miss for the UK. 

[stewfox]

15 minutes ago, radiohead said:

With -16 uppers poking into Greece....

 

We had them 10 hours ago, we can ask Gfs 0z to bring them back tomorrow . 

[sorepaw1]

13 minutes ago, cheese said:

I doubt it.. Greece's good weather is one of its few selling points right now. The last thing Athens needs is a blanket of snow driving away northern Europeans looking for some warmth! 

But yes, I'm sure we'd see some very cold nights under that high. Similar to what we've been seeing recently.

If not colder tbh with total respect to your post.

[Allseasons-Si]

the EC ens are out,more clustering trending colder mid to long term,ECM a mild outlier on the 5th

better control run this time at 192hrs with a strait northerly blast.

 

Edited December 29, 2016 by Allseasons-si

[Mucka]

GFS ensembles are out tot he end of high res and steady as she goes with roughly the same minority of members leaning more toward UKMO - about 65% for strong ridge/Northerly and another 15% for flatter ridge and Northerly.

[kumquat]

12 minutes ago, Singularity said:

 

For what it's worth, I believe the 18z places things too much 'in the balance' for the inherent bias toward the northern jet arm to be subdued this time around. It's GFS sniffing at the ECM way forward but not committing strongly enough to overcome it's own foibles. Just my opinion, mind.

It would be great if you could expand on this a little, as I can't quite get my head around your thinking. Are you saying that there is an inherent bias in the GFS to concentrate on development of the northern arm of the jet (in this set of data) but it is "testing the waters", so to speak, in trying to subdue that route and try something else?

[snowhope]

Is it still generally the concensus that we should compare runs to the previous days or to subsequent runs now? eg 18z yesterday for 18z today?

[TEITS]

Having followed all the model runs today I would refrain from making any predictions. We all know we are in for one hell of a rollercoaster ride. At this stage the 06Z, 12Z, 18Z GFS runs are all viable. If we went on recent history then the 18Z is more likely than the 06Z. However im not a massive fan of using recent history because I remember just prior to 2009/2010 winters someone created a thread asking what has happened to the Greenland High!

What those who are new to following models need to realise is the reliable timeframe varies with each winter set up. For example a set up like 2009/2010 with a Greenland high is less prone to changes compared to a Scandi HP. Imagine a dartboard, the bullseye i.e the UK is much larger with a Greenland high than the Scandi HP as the bullseye can be tiny.

Im sure we all want to know if the E,lys will come off. However whilst the ECM +216/+240 is a classic E,ly in the making I want to see +216 at +72.

 

[Gael_Force]

3 minutes ago, Allseasons-si said:

the EC ens are out,more clustering trending colder mid to long term,ECM a mild outlier on the 5th

 

Yes, EC 32 suggests 1 to 2c below normal for the CET region for 3 weeks. Is it time to try another low figure for the competition or will it all change like this month.