Model output discussions pm 31/12/15

[bobbydog]

18 minutes ago, The PIT said:

Surprised nobodies posted the beast from the east

 

 

we have to get rid of the 'Pest from the West' first....

 

[IDO]

9 minutes ago, karlos1983 said:

Not really the beast we are after, more of its lame lesser cousin. Which is pretty unlikely to verify, very weak ridge that is certain to get shoved east as is usual with the GFS imo 

Yes it's the 06z and very unreliable of late after D10. Another GFS OP with no apparent support:

The GFS OP's in FI even on the 0z and 12z are in a state of flux at the moment as they respond to the background signals so it is hard to take them serious (more than normal!) with regard to developments at that range. The main theme for the next 10 days are rainfall totals and the op run up to D10 is showing some very high totals. More so for the western regions, and the south not escaping the deluge from a more westerly Atlantic flow:

[nick sussex]

16 minutes ago, BLAST FROM THE PAST said:

Will probably post longer after the 12s but I can't understand the despondency. Yes we fail on the direct hit but the chances remain of more shots at cold, and I don't think they will go away either.  We haven't seen the well vaunted pressure rise from the SW have we...

BFTP

Lol! yes the pressure rise looks to have bitten the dust. I wonder does Glosea and some of the other UKMO models actually include an MJO tropospheric response. They obviously have MJO forecasts because we see them, perhaps they think the El Nino will completely override the MJO which is bizarre because NCEP have clearly stated that the MJO will impact the NH pattern and to use their words " destructively interfere with the El Nino downstream response".

Its for this reason they've had to change their January outlook,  of course the question is what effects that will have in Europe.

At this point I'm still happy to go for the displaced Azores high to the nw  initially with eastern USA troughing, and troughing towards Scandi.

Edited January 2, 2016 by nick sussex

[Captain Shortwave]

19 minutes ago, nick sussex said:

Lol! yes the pressure rise looks to have bitten the dust. I wonder does Glosea and some of the other UKMO models actually include an MJO tropospheric response. They obviously have MJO forecasts because we see them, perhaps they think the El Nino will completely override the MJO which is bizarre because NCEP have clearly stated that the MJO will impact the NH pattern and to use their words " destructively interfere with the El Nino downstream response".

Its for this reason they've had to change their January outlook,  of course the question is what effects that will have in Europe.

At this point I'm still happy to go for the displaced Azores high to the nw  initially with eastern USA troughing, and troughing towards Scandi.

I can certainly see the disconnect between the classic strong El-Nino pattern and the pattern predicted on the anomalies for the USA in the extended range.

Low heights persist across the eastern parts of Canada for a good part of the run which is against the classic EN-Nino motif of persistent above average heights. I might be wrong here mind you.

A stronger signal on the 06z suite to recover pressure through a good part of western and north west Europe through the later stages of week 2, it at leasts offers something less unsettled if we can get this trend to build. A lot of water under the bridge to get through first, literally.

GEM ens similar 

The best shot at cold pretty much comes from the evolution shown on the operational where low another the lobe of the polar vortex drops into eastern Canada and pushes a ridge in the Atlantic northwards which can drop enough cold air south to allow the ridge to collapse towards Scandinavia instead of building through Europe.

Edited January 2, 2016 by Captain Shortwave

[blizzard81]

5 minutes ago, nick sussex said:

Lol! yes the pressure rise looks to have bitten the dust. I wonder does Glosea and some of the other UKMO models actually include an MJO tropospheric response. They obviously have MJO forecasts because we see them, perhaps they think the El Nino will completely override the MJO which is bizarre because NCEP have clearly stated that the MJO will impact the NH pattern and to use their words " destructively interfere with the El Nino downstream response".

Its for this reason they've had to change their January outlook,  of course the question is what effects that will have in Europe.

At this point I'm still happy to go for the displaced Azores high to the nw  initially with eastern USA troughing, and troughing towards Scandi.

Yes, it's quite odd as the meto long range forecasts are saying drier to south and east. They have gone against their glossea model which was showing height rises to south west. 

[nick sussex]

Yes Captain S, and do bear in mind the time lag in terms of tropospheric response. The dynamic model forecasts have the MJO already in phase 7 , indeed the MJO using the smoothed out version which does its best to remove Kelvin waves and ENSO interference is only just about to leave phase 6.

 

Using the rough timelag tropospheric response should be expected around 10/11 January.

If theres to be some big changes in the outputs then that's the dates I would be looking for to see the models playing around with displacing the Azores high, a bit like what the GFS has been trying to do.

I think its down to the troughing set up in the eastern USA, how amplified will this be?

 

[Froze were the Days]

1 hour ago, Captain Shortwave said:

Indeed PM, the GFS has again found a cold solution for around the 13th/14th onwards. This time an Atlantic low undercuts the developing Atlantic ridge and slides through the channel, northerly follows with perhaps a chance to veer the winds north easterly as the low clears and heights build to the north/north east.

There certainly seems to be a window of opportunity around mid-month again after a spell of unsettled and stormy weather. That said said I would like to see some strengthening anomaly evidence for this from the ensembles and NOAA.

Actually seen that 'window of opportunity' a couple of times show up mid-month on the CFS (monthly) - so certainly something to keep an eye on but unfortunately the high pressure rather than joining heights over Norway (and a prolonged cold spell) the CFS was modelling just a toppler.

[knocker]

As noted in previous posts the GEFs (not the ecm) has been signalling height rise from the south in days 10-15 but it's very dependent even if does materialise, on the orientation of the surface high. It would produce more settled weather but certainly no guarantee of anything very cold

[Glacier Point]

So, following up on previous posting....

This is one of the situations that you just hope everything stays exactly as it is now, allowing for small scale adjustments (from a cold seeking NW European perspective rather than a parochial snow chaser's perspective). It will be one of the changes brought about by seasonal changes in wavelengths.

The atmospheric coupling to El Nino continues with the forecast 'off the scale' peak in overall angular momentum and tendency in relative angular momentum now within the next 2-3 days.

The pressure pattern over Asia looks ripe for further net increase in westerly tendency days 7 and again at day ten, so we may look for an averaged spike around the 10th January, although for the purposes of dating a possible flip in the NAO from poleward fluxing eddies, around the 25th looks to be the target. Look for troughing ahead and downstream of the mountain ranges for periods of transient amplification prior to this target date. These dates may be relevant to short term fluctuations in the jet flow allowing for more northerly component to the flow over NW Europe around / just after mid month.

With the atmosphere loaded in the high angular momentum base state, composites for January GWO phases 6 and 7 showing excellent agreement days 1-15, factoring in some maturing and decline in the tendency of angular momentum as the MJO signal moves into the Indian Ocean (although how long for?).

Phase 6:

Phase 7:

Possibly a little on the progressive side for days 11-15, but around the expected timing of a transient northerly.

Regardless of the MJO entering the Indian Ocean, angular momentum looks to remain high with a strong convective component centred in the central Equatorial Pacific (mature El Nino signal). Ignore the GEFS related products for angular momentum as these will be bogus as the model (or rather the interpolated version of it seen here) doesn't reflect low frequency forcing very well. That takes us to the end of the month, ie. closing in on February. How does a continuation of the mature El Nino pattern look to be for February ?

The point being that the closer we get to February, the greater the trend for any west based -NAO to correct more eastwards. Also, using the MJO for guidance during the second half of January will be of low value, with the GWO (which measures extratropical-tropical interactions) much more relevant.

CFS weeklies and 06Z GEFS mean of interest there...

I have nagging doubts about the stickability of ridges in that locale given the pattern of the last 8 months, although you could make a solid argument here for eventual evolution of a Scandinavian ridge from that. Bottom line looks to be continued reasoning using the Global Synoptic Dynamical Framework for height rises to the north, north-west of the UK and possibly NE in time towards the end of the month, or if you like it, the closer those composites get to reflecting the atmospheric parameters associated with February. Cold likely to be from the north from this pattern, and could well be something of a north-south divide, but that detail will only be resolved closer to the time.

Steady as she goes..

 

 

 

 

Edited January 2, 2016 by Glacier Point

[johnholmes]

The 500mb anomaly charts I use are all reasonably consistent in the theme of a westerly flow across the Atlantic into the UK and Europe. Quite a strong flow and not mild overall with contour values below 540dm generally over the far south of the UK. No sign of any troughing down into Europe to any extent and 2 out of the 3 have no indication of +ve heights over N Norway. These +ve heights and ridging mostly extend in a swathe from the northern half of N America now into Greenland and towards the pole, although troughing is now evident in the polar areas on EC-GFS but not really on NOAA.

Anyway the usual links are below.

My take is this, from my daily close checks of them

Sat 2 jan

Ec-gfs

The main changes  from the charts shown above are the increase in heights towards Greenland from w/nw of there on the above charts and the replacement of the ridge  n of n Norway with troughing from the flattish type of trough governing uk and European weather in the main, still low contour heights on both. Some differences but not major ones around uk or even further west.

They and noaa 6-10 last night confirm the pattern will remain about w’ly 6-14 days ahead with relatively low contour heights (differences in values noaa to ec-gfs as often is the case).

So remaining unsettled, even stormy perhaps at times for the NW’ern half of the UK, surface lows tracking towards NW Scotland, not mild other than as lows swing towards and extend their fronts over the UK, colder behind with a more settled short lived spell. Snow being confined, mostly, to the hills from N Wales north but some pre frontal snow to lower levels from about the same areas. No signal yet that I can see using any of the models/teleconnections available to us for any deep longer lasting cold.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

http://www.cpc.noaa.gov/products/predictions/610day/fxus06.html

[Coopsy]

There's always a lot of talk about the beast from the east on this thread - here's a great vid (apologies mods if its off topic too much - feel free to delete) of how the models were in the run up to the great Jan 1987 event running from December (which shows a surprisingly similar mild trend to this December) to the big event. I'm not implying in anyway its at all similar this year just interesting.

 

Edited January 2, 2016 by Nemesis

[knocker]

And just to throw this into the ring the  EPS Parallel 46 day output has the European HP ridging north over the UK 18th-28th.

Edited January 2, 2016 by knocker

[I remember Atlantic 252]

I have been looking out for high pressure in FI, still trends for it to build, I would even pay for this to come off, if only, we deserve a break, especially flooded areas of the north

[Su Campu]

Huge spread in the ECMWF ensemble means on that deep low around midweek. The hi-res operational gives sub-940 hPa but the mean is more like 964 hPa. A large spread in the strength and position of the upper trough too.

Edited January 2, 2016 by Su Campu

[blizzard81]

45 minutes ago, knocker said:

And just to throw this into the ring the  EPS Parallel 46 day output has the European HP ridging north over the UK 18th-28th.

I would bank that right now. The amount of rain is absolutely ridiculous now, shocking.

[blizzard81]

1 hour ago, Glacier Point said:

So, following up on previous posting....

Steady as she goes..

So looking more and more like a mediocre affair by the looks of it. Certainly for the rest of Jan anyway. One transient northerly in Jan does not a winter maketh imo.

Edited January 2, 2016 by Polar Maritime
To reduce long quote.

[mushymanrob]

2 hours ago, The PIT said:

Surprised nobodies posted the beast from the east

 

 

possibly because people are now more aware of getting too excited over one or two fi charts that dont have support?...

the anomaly charts would suggest that any such synoptic chart would only be brief (although i suppose welcome) affair.

[Glacier Point]

@blizzard81 I think maybe you interpretation of that would be different to mine..

Northerly flow period occurring during 15th-20th January, candidate pattern shift to classical -NAO around 25th/26th January.  If the cards fell right, that could be cold throughout and would certainly denote potential for the second half of the month to be colder than the first, more likely the latter third.

 

Edited January 2, 2016 by Glacier Point

[Duane S.]

1 hour ago, Nemesis said:

There's always a lot of talk about the beast from the east on this thread - here's a great vid (apologies mods if its off topic too much - feel free to delete) of how the models were in the run up to the great Jan 1987 event running from December (which shows a surprisingly similar mild trend to this December) to the big event. I'm not implying in anyway its at all similar this year just interesting.

 

Quite agree that on the face of it, this is not too dissimilar our December pattern and it is easy to wonder, did we just miss out?? I very much doubt it. I am not a great believer in simple year-on-year analogue comparisons. There are just too many drivers in force and it is their mind-blowing complex interactions with other that keeps us from being able to forecast the weather any better than we are currently able to (and in my view, ever will be able to).

So as is almost always the case when doing these,it does seem things were running differently back in the run up to that event, so with the small amount of relevant (or maybe not, who knows?) data available, the differences were, IMO, not insignificant...

We are in a declining W-QBO pattern, Jan87 was in an inclining E-QBO pattern.

We are in the midst of a strong El-Nino peak, Jan87 was in a moderate inclining El-Nino state.

The temperature in the higher latitudes has been running at about 10 degrees C cooler than back in Dec'86-Jan87, in conjunction zonal winds have been stronger this winter as well, this vortex on paper looks a much tougher nut to crack than the one back then.

There was a strong wave2 peak mid December, I suspect this could have helped split the tropospheric vortex shortly afterwards, we on the other hand, have had very low wave2 action thus far this winter.

There was moderate to strong (and maybe crucially, constant) wave1activity from Mid December '86 onwards, this is closer to what we have had but Dec'15 has been more sporadic in nature. Although, this is probably looking to increase as we head into January.

Jan '87 delivered because the atmospheric drivers / state listed (combined with numerous others not listed) came together ( with nigh-on perfect timing) to give us that remarkable event. So whilst a repeat of that cold spell will no doubt appear again (at some point) in similar guise on the 500hpa charts, it will never be as a result of that exact combination. There were/are some pre-requisites though and we can at least look out for those. Vortex disruption, established heights in and around the Arctic area, subsequent severe cold pooling to our NE and most crucially the nosing down (as opposed to a ridging up of a Mid-lat high) of a fully fledged Arctic high. So currently with meandering heights around the pole, very cold pooling to our NE it is not impossible to think that, for all we know... with slightly different underlying conditions, a Jan'87 repeat was (still is?) as close to repeating this year as any year since. Hence why I was very interested by the unusual vertical WAA surge to our east up into the pole and what happened next, any time that happens in winter it opens up a rare window (however small) to an extreme event like the early Jan-87 event.

Anyway, probably all irrelevant as the the next cold spell (should it appear at all) looks far more likely to come from a more 'conventional' route, aka Greenland hight rises mid month onwards.

 

[January Snowstorm]

Well I for one would be happier if GP was forecasting cold rather than the Meto. I find they chop and change if and when the charts do.

So in that regard lots to look forward to as we await this evenings runs....

[blizzard81]

1 hour ago, Glacier Point said:

@blizzard81 I think maybe you interpretation of that would be different to mine..

Northerly flow period occurring during 15th-20th January, candidate pattern shift to classical -NAO around 25th/26th January.  If the cards fell right, that could be cold throughout and would certainly denote potential for the second half of the month to be colder than the first, more likely the latter third.

 

Thanks GP. My post was more reflective of my rather pessimistic mood today lol. 

[Catacol]

1 hour ago, blizzard81 said:

So looking more and more like a mediocre affair by the looks of it. Certainly for the rest of Jan anyway. One transient northerly in Jan does not a winter maketh imo.

I'm not sure that is quite the correct interpretation of GP's post at all. Did you not look at that composite for February? If the last week of January turns cold, and this intensifies through the first half of February then I think we will all be happy...

... apart from the snow starved members of the South and South West of England. I didnt like the bit about a potential north/south split! I'm gonna conveniently ignore that, and trust in a deep European trough to our south come February.... :-)

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

 

i  know its  fantasy  world  but the gfs is hinting of a possible  change to a bit colder weather  after  jan 12

[blizzard81]

Just now, Catacol said:

I'm not sure that is quite the correct interpretation of GP's post at all. Did you not look at that composite for February? If the last week of January turns cold, and this intensifies through the first half of February then I think we will all be happy...

... apart from the snow starved members of the South and South West of England. I didnt like the bit about a potential north/south split! I'm gonna conveniently ignore that, and trust in a deep European trough to our south come February.... :-)

Thanks Catacol. Mine was just a weary post from a snow starved member lol. Third winter (and counting) of discontent.

[Catacol]

12 minutes ago, blizzard81 said:

Thanks Catacol. Mine was just a weary post from a snow starved member lol. Third winter (and counting) of discontent.

Ha - me too.... Got to go back several years for any snow here in lowland Somerset... and there wasnt any at all from 1999 - Feb 2009 in my first 10 years here (bar a brief flurry in Nov 2005 I think...). Enough to make the teeth grind a-plenty.

But with both GP and RJS going for some cold in the not too distant future there is enough to be interested with. As I'll have to post a model chart to avoid being binned, let's look at something like this from mid month as a starting point. It certainly fits GP's thinking of "transient amplification" to start off winter proper... 

Edited January 2, 2016 by Catacol