Jump to content

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


Recommended Posts

  • Replies 7.9k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Evening All For those of us who have been here for a long while there is times when you know you have to throw in the towel on chasing cold & times ( very rare ) when you 'just know' that the

Boom goodnight vienna

People being a bit harsh on Steve Murr, at least he has the balls to try and read and predict what may happen from his viewpoint rather than just posting what charts show.

Posted Images

The extended eps is again broadly similar to the last few runs though higher heights over Europe is pushing the jet a little bit further to the north meaning that the 850's are anomalously warm right through to day 15.  From what the NWP is showing, it's a long way to cold.  However, we all know things can change quickly but for the sake of your sanity reign in expectations for the rest of this month and early February.

  • Like 3
Link to post
Share on other sites

Re Singularitys post this MJO update from NCEP is interesting, they're suspicious of the GFS weakening of the signal. Additionally it could be that the correct MJO signal has already quickly gone through phase 8, the original outputs picked that up but the ECM is now seeing more phase 1.

The ECM changes between outputs suggests the MJO could be causing this jumpiness.

 While the RMM index indicates weakness of the MJO at present, Hovmöller analyses depict the eastward propagation since late 2016 of an intraseasonal signal presently over the Western Hemisphere.  The CPC velocity potential MJO index appears to have done a better job tracking this signal. 
 The low frequency background state continues to influence the tropics and subtropics, with suppressed convection in the Central Pacific and enhanced convection for the Maritime Continent. The subseasonal signal appears to be destructively interfering with the convective signal over the Maritime Continent in recent days. 
 Dynamical model forecasts of the RMM index support an emerging MJO signal in the Western Hemisphere during Week-1 that continues into the Indian Ocean during Week-2.  Uncertainty is high late in Week-2 where ensemble mean forecasts support weakening of the MJO, although this could be tied to inconsistent simulated phase speeds cancelling out with one another.
 

Further on:

The GEFS forecast depicts an emerging MJO signal over the Western Hemisphere in the next few days.  This signal is forecast to continue into the Indian Ocean during Week-2 before the ensemble mean supports a weakening signal around the 25th of January. 
Caution should be exercised with the weakening forecast late in Week-2 as differences in the model forecast phase speeds of the intraseasonal envelope could be destructively interfering. 
Continued eastward propagation is consistent among ensemble members.

The ECM monthly could also be wide of the mark because it also wants to weaken the signal quickly into the COD.

Whether we get to anything interesting is still open to debate but its unlikely the MJO won't have some impact on the NH pattern. The ECM op output looks like a response to phase 1.

  • Like 5
Link to post
Share on other sites
1 minute ago, Nicholas B said:

Nope I believe it is what the chart shows for the majority of the uk, yes high pressure is in control of the vast of Europe but we are talking about the UK. we will have to agree to disagree. High pressure is clearly in control as we speak and it is grey and drizzly in my location so I understand what you say, but if you watched the BBC forecast for the day shown (if it turned out that way) they would not be saying high pressure in control. We will have to agree to disagree  

Ok, I happily agree to leave you to your subjective perception rather than an objectively veracious view.

  • Like 5
Link to post
Share on other sites

Any chance of a ridge being thrown up ahead of the Atlantic low around 144 on ECM? Very unlikely and the 00z flattens things at 168,  but with little forcing coming out of Newfoundland its a wildcard option.

IMG_1778.PNG

IMG_1779.PNG

  • Like 2
Link to post
Share on other sites
33 minutes ago, Seasonality said:

Just to emphasise the differences between the two most recent ECM runs.

ECM1-240 (3).gif

ECM1-240 (4).gif

Nicely illustrates the uncertainty as we enter the last week of Jan. This is another reason why I take GEFS means at D10 and monthly ECM forecasts with a huge dose of salt.

I would be eager to hear GPs latest thoughts on how we may progress forward.

  • Like 3
Link to post
Share on other sites
4 minutes ago, Nicholas B said:

OK mate, and I will leave you to yours :)

 

High pressure is controlling our weather on the ECM charts. Only after +240 does low pressure start influencing our weather. The only exception is the far N of Scotland at +216.

  • Like 6
Link to post
Share on other sites

Some excellent information there @nick sussex, thanks for that :good:

ECMF_phase_51m_small.gif

It has to be said, interference or no, the current ECM ensembles paint a very interesting picture going forward i.e. into the first half of February. Having the MJO propagating steadily into and then likely across at least part of the Pacific while the stratospheric vortex undergoes significant weakening (or, who knows, even a SSW), well that would be a mighty combination.

The spread is balanced around the COD though, so no assumptions can be made here - but the words of NCEP are encouraging :)

  • Like 5
Link to post
Share on other sites
22 minutes ago, TEITS said:

High pressure is controlling our weather on the ECM charts. Only after +240 does low pressure start influencing our weather. The only exception is the far N of Scotland at +216.

With High pressure close by to the South East and Low pressure close by to the Northwest, how can one be in control? The 1013mb line at t216 is over northern England which is central UK, 1013mb is the standard pressure for the UK as stated by the Met (neither high nor low). If at t240 low pressure starts to become dominant then that should say something to us? Anyhow i'm out numbered here by you guys so guess I must be wrong, in which case I will eat humble pie!  

  • Like 4
Link to post
Share on other sites

Can we please get back to the models guys.:)

 

Seems to me that HP is in control for the next week or so, and if anything holding on a bit longer on the 06z. Pretty cold charts on the whole, some frosts and a few grains of the white stuff on higher ground. 

gfsnh-0-48.png

gfsnh-0-162-2.png

Link to post
Share on other sites
5 minutes ago, snowray said:

Nice chart at T192, now LP starting to dominate, Euro slug being shifted at last, and is that a bit of yellow and green there that I can see up towards Greenland? gfseu-0-192.png

gfseu-1-192.png

I think you are on a wasted journey expecting a height rise into Greenland within the next 10/12 days.

of course the extended modelling may flip completely but I doubt it would to that extent

  • Like 3
Link to post
Share on other sites

finding any positives on the gfs 6z is a big ask imo and things just look to drift on towards the latter part of jan.ssw- mjo nothing seems to bring any other outcome other than whats past since late november.todays ecm does show some promise i guess but i sound like a broken record.i wonder if a "backloaded" winter is the next way forward:rofl:

 

Edited by swfc
  • Like 1
Link to post
Share on other sites
2 minutes ago, snowray said:

Just trying to be a bit more optimistic thats all...There is some scope there for a toppler I think though, around D10.

gfseu-0-240.png

Maybe not headed for a Greenland High but I think there is room for optimism all the same. The pattern does seem to want to head east - if the models are under-doing the signal for progression, we might get a tasty low from the Greenland area - the latest GFS a case in point:

from gfs-0-240.png?6  to gfs-0-300.png?6

maybe a long way off but not  inconsistent with some other output

Link to post
Share on other sites

Oh my word the 00z and 06z GFS bring new levels of awfulness to the medium term for cold lovers. Long and screaming SWerlies running up one of those horrible 'escalator' high pressure systems. And there is no cold of note pooling to make any change to the pattern worthwhile from that cold perspective. Hard to find anything enjoyable for anyone who isn't a fan of windy winter weather.

having said that of course, it will be immense fun on the hills and mountains of Scotland, where such conditions bring white gold to theadventurous.

  • Like 4
Link to post
Share on other sites

The GFS 06hrs run moves towards the ECM solution in the early stages, whether this is a one hit wonder from the ECM and its new evolution we'll see this evening but the trend to amplify troughing over the central USA downstream causes the jet to angle more se'wards by T240hrs.

If this trend doesn't hit the buffers I fear we may soon start to be chasing another east/ne flow!

 

 

  • Like 5
Link to post
Share on other sites

When the 06z does finally move it succeeds in bringing Atlantic sleet above a couple hundred metres to Donegal and western Ireland and maybe a flake or two for elevated Ulstermen. What a dreary and depressing set of runs. and no sign of any stratospheric warming, sudden or otherwise on display. 

Link to post
Share on other sites
24 minutes ago, nick sussex said:

The GFS 06hrs run moves towards the ECM solution in the early stages, whether this is a one hit wonder from the ECM and its new evolution we'll see this evening but the trend to amplify troughing over the central USA downstream causes the jet to angle more se'wards by T240hrs.

If this trend doesn't hit the buffers I fear we may soon start to be chasing another east/ne flow!

 

 

Perish the thought Nick, cannot go down that road again this winter:wallbash:

  • Like 3
Link to post
Share on other sites

Just an observation, but the 06z extends sub zero surface temperatures over central, eastern and south eastern Europe, as did the 00z ECM, albeit in a different form. Changes afoot or one run blip? More interesting model watching, that is for sure.

  • Like 2
Link to post
Share on other sites

Morning All :)

Into the second half of winter we go.

The current "problem" is the HP over Canada is drawing cold N'ly air down into the Atlantic encouraging cyclogenesis and firing up the northern arm of the jet.

Further down the line into FI (and I do wonder if this is the initial response to the warming on the Eurasian side), the PV energy gets bounced back over to the North American side and we get the PV shunting cold air south and encouraging cyclogenesis etc,

So we first have an unfavourable tropospheric scenario followed by an unfavourable stratospheric scenario. That said, the GFS in FI is giving the PV a real hammering at 10 HPA so IF the "warming" happens (whether an actual SSW with reversal or not), we will have a much weaker PV in February than last year when all we got was a much earlier final warming. The hints at blocking in February support the scenario of a weakened PV but I'm not expecting a Greenland HP - I think Scandinavia will be the more likely option.

As we've seen, the standard response to a period of "disruption" is a 10-14 day reset of Atlantic domination. We're probably looking at that now in all honesty from the weekend and next week could be very mild in the south. That said, we're not really seeing the Atlantic in full fury as past winters - the "interest" is the modelling of secondary features which "could" be nasty in terms of wind and heavy rain (and plenty of potential for snow to altitude).

It's worth pointing out once again that even with two weeks "gone", there's a full third of winter left and as past winters have shown, March is more than capable of delivering lowland snow and cold (perhaps not on the scale of the exceptional 2013 experience though there was an SSW at that time).

  • Like 6
Link to post
Share on other sites
41 minutes ago, Seasonality said:

Just an observation, but the 06z extends sub zero surface temperatures over central, eastern and south eastern Europe, as did the 00z ECM, albeit in a different form. Changes afoot or one run blip? More interesting model watching, that is for sure.

Certainly some decent surface cold in the areas you mention, O6Z for the UK is not great though with the current HP sinking SE with the only chance of anything cold in the UK being some brief PM incursions, lets hope the ensembles show a glimmer of something we are looking for toward the back end.

EDIT out to t240 the ensembles have to be the worst for cold possibilities I have seen for the UK this winter :(. As Blue army said, I think we are going to have to take the medicine before anything.   

  

senspanel2401.gif

Edited by Nicholas B
Link to post
Share on other sites
Guest
This topic is now closed to further replies.
×
×
  • Create New...