Model output discussion - 1st December onwards

[bobbydog]

i know we're looking at record temperatures but.....

 

[Newberryone]

Tidings of joy perhaps for coldies post Christmas. Could very well be for we're all very well aware of the fact that the professionals have access to considerable more data output than us mere mortals. Met Eireann forecast on RTE at teatime stating that there are now signs of the weather possibly turning "much colder" from the 25th onwards. 

Perhaps not relevant quoting the professionals I know mods as this is a model discussion thread, but as we're all championing the same cause, i.e. cold weather prospects, you might on this occasion take heart. 

[draztik]

6 minutes ago, Newberryone said:

Tidings of joy perhaps for coldies post Christmas. Could very well be for we're all very well aware of the fact that the professionals have access to considerable more data output than us mere mortals. Met Eireann forecast on RTE at teatime stating that there are now signs of the weather possibly turning "much colder" from the 25th onwards. 

Perhaps not relevant quoting the professionals I know mods as this is a model discussion thread, but as we're all championing the same cause, i.e. cold weather prospects, you might on this occasion take heart. 

Gefs say no. 

[mountain shadow]

4 hours ago, Newberryone said:

Tidings of joy perhaps for coldies post Christmas. Could very well be for we're all very well aware of the fact that the professionals have access to considerable more data output than us mere mortals. Met Eireann forecast on RTE at teatime stating that there are now signs of the weather possibly turning "much colder" from the 25th onwards. 

Perhaps not relevant quoting the professionals I know mods as this is a model discussion thread, but as we're all championing the same cause, i.e. cold weather prospects, you might on this occasion take heart. 

Unfortunately much colder simply means a return to average or slightly below as polar North Westerlies occasionally impact the North and West. 

They most certainly do not mean Northerly blocking with snow and ice.

[Severe Siberian icy blast]

1 hour ago, Froze were the Days said:

Doesn't mean anything - PV wasn't in control of our weather the first week or so of November but we still had very mild conditions. ok not full on Atlantic stuff but so far this late Autmn/early winter has 'found ways' of continuing this mild headache!

The 2 main reasons why this December has and still is exceptionally mild is : 1 a record breaking El Niño pattern which favours an extensive European ridge , and 2 : wQBO which helps to wind up a strong mighty vortex early doors in winter . Low pressure to North , high pressure to South  = southerly/southwesterly uncle Barty !! 

I for one can not wait to get rid of this disgusting warm mush . A land on our latitude should not have 16c and grass growing in December .  I can't remember the last time I saw the sun , let alone a frost . 

Thankfully signs of a change afoot , a northwesterly air stream for 7 days or so into the new year followed by a break down of the vortex come mid jan would be great .  Like many have said already , winter 12/13 started around 12 jan with the first significant snow Thursday/Friday 17th , which continued off and on until April .  December was always a right off and so far bar a slight delay things seem to be going to plan for chiono's forecast , which will be incredible given the limited data smaller organisations have . 

Hears to a very snowy second half of winter 

Edited December 18, 2015 by Severe Siberian icy blast

[mountain shadow]

4 hours ago, Greenland1080 said:

However...that could be the first step on the road to Northerly blocking with snow an ice...lots of models showing signs of waa pushing north to put pressure on the vortex....could be a very interesting start to Jan 16

We are weeks away from any severe impact on the PV,  mid January at the earliest.

I haven't seen one model that says otherwise. 

[nick sussex]

Looking at the ECM ensembles they seem reluctant to change the orientation of the Euro high with the main wind cluster south/sw.

The main spread at day 10 is to the north of the UK so the issue of ridging in that region is still the main uncertainty.

There are some differences between the ECM/GFS and UKMO at T144hrs. The latter has a stronger ridge near Newfoundland and is more amplified upstream.

The set up for the UK is quite complex because any high developing further north is reliant on the deep low digging south to the west, the movement of this low is effected by the pattern over the USA and Canada and how any amplification in the Pacific effects that region aswell as the movement of the PV.

In terms of the ECM/GFS T240hrs I'm finding this a hard sell, we've seen this before with split PV's becoming unsplit! I think a ridge extending north has a decent chance as long as the low to the west is sufficiently amplified but the  split PV would be a big turn up given the background signals.

In terms of Christmas/Boxing Day this forecast is looking a lot more complicated than what we could have expected a few days back.

As that upstream low digs south and hopefully amplifies it could send some shortwaves ne in towards the UK, depending on  the amount of cold over the UK at that time theres still a small chance of some snow on the west/nw flank of these.

The ECM 00hrs did suggest that, this shortwave activity near the UK however could be a spoiler if it phases with the upstream low.

Things to look out for tonight is the deep low to the west around T192hrs, you want this as far south and west as possible, more oval at least and not football shaped, it might start out as the latter but the sooner it sharpens up the better chance you have of developing WAA ahead to develop high pressure.

Theres still a lot of hurdles to overcome to develop some colder conditions for the UK and we should view this as a bonus feature in that a few days back a realistic way to cold would have needed a good fiction writer!

 

[SMU]

Well the GFS 18z looks a carbon copy of the UKMO 144 which was more amplified than the 12z GFS-

A more positive day which has seen a larger amplitude develop in the waves, with the ECM looking very wave 1 like at t240-

with the 18z more amplified - hopefully the festive period will become even more colder-

belfast & glasgow a worthwhile punt on a white Christmas ....

 

s

[nick sussex]

That shortwave to the sw is too developed, we want a weaker feature to bring this into the UK not too far west. And we don't want this shortwave anywhere near the upstream low.

Game over shortwave phases with troughing which tugs this eastwards. Its like pulling teeth sometimes!

If this shortwave runs ene into the UK someone gets a nice surprise over Christmas/Boxing Day with a chance of some snow, if it develops and runs more like the GFS 18hrs it all goes pearshaped.

Edited December 18, 2015 by nick sussex

[Hotspur62]

It is encouraging to see models are showing tentative signs that changes maybe afoot but I think it will be a good few weeks before we get a nationwide cold spell.

In the meantime it looks like another t-shirt and short day down here in the SE lol

 

P.S. Good to the see SM back-a sure sign cold weather is on the horizon.  

[Nouska]

If you haven't noticed, Sylvain is running the new GFS in parallel: it looks to be a bit sporadic in downloading but always something else to look at.

The mid day charts for Christmas below - current and then new model.

      

Link here   .....    http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=0&runpara=1

      

[Paul_1978]

I've seen the term "Sceuro High" bandied about on here a lot recently - where exactly is 'Sceuro'?

[pyrotech]

i think looking at the two main models tonight ( GFS & ECM), that the focus is on rainfall between now and Christmas day.

Whilst i do want to see some seasonal weather, my thoughts are with those that have had such a dire start to the festive season. The models hint of those same areas getting large rainfall totals again.  The areas namely - southern Ireland, Wales ( Esp North and West) then later to include possibly Cumbria and Western Scotland.

A lot of shannon entropy on how much and where but whilst we model watch here looking for winter, i think this deserves some discussion on each run as it could have some major disruption in some peoples lives.

Does anyone see anything different as my analysis is this is a large risk with over 100mm of rain for some soaked areas over the next week, mainly due to orographic rainfall.

[Allseasons-Si]

Just got in

there has been some great posts today,thanks

i would like to see the 168 ukmo chart as i think the 144hrs was pretty good in my eyes with WAA pumping up off the eastern seaboard behind the trough to our NW,could be a cold xmas

 

the 18z gfs as a bit of interest on Chrimbo day with a shortwave running through with the 0c isothern into the south of the county with some pocket of -4 uppers across central parts too,also some backend snowfall from that shortwave

so a cooler run from the latest gfs,of cause it's still a week away but slowley catchy catchy as they say

after that,this will be Knockers Daffs

and his woodshed will look like this

Edited December 18, 2015 by Allseasons-si

[MJO]

4 hours ago, gottolovethisweather said:

 And it is as if tonight's ECM has read the script, my script that is. 

Hi..Maybe the question mark will go to middle east / Israel maybe ! 

Edited December 18, 2015 by MJO

[kumquat]

19 minutes ago, Paul_1978 said:

I've seen the term "Sceuro High" bandied about on here a lot recently - where exactly is 'Sceuro'?

Probably something like this:

 

Signs on the previous overnight 0Z ECM 240 especially of this pressure, pumped up by WAA, digging into East Greenland

 

 

It's all like NS says about the downstream activity of that deep low and where and how potently it starts pumping up the High in our area via WAA.

Either way, a worrying lack of cold in Europe doesn't bode well for us. Most models that do show a dig down of cold bring it into our old friends in Greece / Turkey.

Still a chance we could experience the same just before New Years' Eve.

More, I believe under-modelled activity over in the Alaska / Bering will undergo rapid enhancement and snag the proposed Sceuro West. Models might well latch onto this late.

No snowmageddon yet, but much colder at surface 10 days out than currently progged and some thinking to do in terms of where we go next.

[Ian Francis]

1 hour ago, pyrotech said:

i think looking at the two main models tonight ( GFS & ECM), that the focus is on rainfall between now and Christmas day.

Whilst i do want to see some seasonal weather, my thoughts are with those that have had such a dire start to the festive season. The models hint of those same areas getting large rainfall totals again.  The areas namely - southern Ireland, Wales ( Esp North and West) then later to include possibly Cumbria and Western Scotland.

A lot of shannon entropy on how much and where but whilst we model watch here looking for winter, i think this deserves some discussion on each run as it could have some major disruption in some peoples lives.

Does anyone see anything different as my analysis is this is a large risk with over 100mm of rain for some soaked areas over the next week, mainly due to orographic rainfall.

I agree...sometimes tire of all the hunting for cold charts when other significant events are showing on the models. GFS 144 hr rainfall totals for NW England and Wales getting very worrying yet again, increasing as they do with every run.

 

Edited December 19, 2015 by Ian Francis

[bluearmy]

1 hour ago, Paul_1978 said:

I've seen the term "Sceuro High" bandied about on here a lot recently - where exactly is 'Sceuro'?

Paul, it means highish heights over Scandi which have their roots in Eastern Europe.  So no undercut possible and no cold advection towards w Europe. (Scandi/euro = sceuro)

 

hopefully you you will be asking about the gricelandic ridge next month!

[Duane S.]

Ok it's 'only' the 18z, ok it's only one GEFS member but in times like this you've got to dream...

 

[January Snowstorm]

The ecm for Christmas day is a hare's breath away from delivering a white Christmas to the North and West.

I said a few days ago that Christmas day would take a while to be sorted. The likelihood is of course that it won't happen BUT a brave man would bet against it right now!! ( for Northwestern regions)

[KTtom]

Rather nice ECM continuing the trend from Yesterday, if we managed the much fabled cut off low in the Atlantic we would probably have one of the most dramatic model turnarounds in modern history!

[That ECM]

2 minutes ago, KTtom said:

Rather nice ECM continuing the trend from Yesterday, if we managed the much fabled cut off low in the Atlantic we would probably have one of the most dramatic model turnarounds in modern history!

Or the ecm is overdoing the amplification and it would go a similar way to the gfs! Still, it is at least a bit of interest I guess. 

[northwestsnow]

some very mild uppers into the heart of greenland at 240h,surely this will help disrupt that horrid pv.

Edited December 19, 2015 by northwestsnow

[legritter]

Just popped in before mad saturday shopping ,and certainly some nice looking  interesting and eye candy charts this morning .

Ecm could lead us into something more seasonal but we need high pressure a bit further north but at least its being modelled and also some interesting low pressure around ,our forum will certainly not be boring but later further outlook still not sorted , looking better now from a coldies view so thats good 

[IDO]

Well ECM does love to produce awesome D10 charts, shame each run they are different. Anyway this morning its heights and WAA towards Greenland: 

  GEM At D10  

GEM looking good for a height rise as does the GFS op. However again the GEFS are trending the other way and that now includes the control run, which is now very flat with little amplification. Always the case when a wave is introduced to a stable pattern and I suppose we just have to wait till the models sort it out. What is unfortunate is that both the GFS and ECM op are notorious for over doing the longevity and latitude of these amplifications, however the experts on here are very sure we will get a Sceuro block so its a case of waiting till the ensembles catch up.

The GFS still no sign of any MJO signal for Phase 6 or 7: 

Both the AO and NAO were showing signs of going negative but now they look like they were moving into a lower positive range, but now reestablishing into a higher positive stage over time. CFS weeklies for 2 and 3 now showing the sceuro heights, as you would expect as the CFS has been leading the MJO signal:

   

As for whether this will bring anything other than mild to the UK in the short term (up till D10) is unlikely as the ECM op is showing some very mild uppers from D7-10 inclusive. If the GFS is wrong with the MJO signal then expect flips from its ensembles soon as its D10 and D12 means don't offer much hope of some propagation to the strat:

    Strat at D16: 

Hopefully the weekend's model output will resolve these issues and we will know whether the strat can get a prolonged attack as currently the strat, although stretched is proving resilient. Its the long way to an SSW via a stretched PV I think. As stated before the experts believe the MJO is very quiet at the moment and that MJO models will flip back into the COD with more runs: https://twitter.com/xerophobe_ww/status/677975990656630785 , so what will actually happen is still debatable till this MJO signal is resolved, as if it is a fast Kelvin wave then it may be a brief meridional flow?