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Model Output Discussion - 30th November onwards


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Thanks OMM, Nicely explained and put in terms that most of us can understand.  I agree with your comments that "it just looks all wrong".  I cannot believe the "glancing Northerly",  I think the charts shown yesterday will be closer to the mark than those produced today. Why? I can't tell you, but, like you, looking at the charts there does seem to be a tendency of the models to shove everything off East (Steve Murr's Eastward Bias)

Thanks NNW, we won't know for a day or two yet, but like I said, developments in the W Atlantic will certainly influence whether any cold is short-lived or not. A lot of what I say is based on how similar situations have developed in the past, not that any two situations are ever exactly the same, but it does quite often happen that HP positioned where it is now, will pull away to the W and NW. One other point I forgot to mention is how the Greenland HP has been forecast to grow pretty intense, something else which suggest to me that HP will link N/S across the mid-Atlantic, at least for a few days. The models should prove interesting this week!
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GHASTLY GFS 18z

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A wretched profile there heralding a BBQ December - yuk

 

Still not to worry there's a mighty Scandi High in FI

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Talk about a Nick Sussex rollercoaster special! Posted ImagePosted Image

Edited by Purga
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Once again, an easterly cometh

 

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I think people are going to have to accept a few days of southerlys to enable the potential easterly.

Yep, the high builds once again

 

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I wouldn't put any stock in this run, looks far too progressive and flat through the mid range even if it does eventually want to build high pressure over Scandi, unless the ensembles and Euros start to support something similar.

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WAA right into the Arctic

 

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Thx,and I just about understand a WAA.  But this option seems so far from any other so why should it happen? And if it does please give a  clue as to what happens next

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It does look like a brief Arctic spell.

The T96/120 fax's

 

Posted ImageNEATL_AB_SurfacePrognosis_UNCL_1200_T096.pngPosted ImageNEATL_AB_SurfacePrognosis_UNCL_1200_T120.png

 

much in line with the raw output by the looks.

A cold,frosty weekend to follow under the high then it all depends on where the block goes from there.

Disagreement even in the ens tonight on next week-a lot to decided yet.

 

Hopefully they will change with UKMO output tomorrow. The UKMO 12z was comfortably furthest East with pattern out of all the output so unless it is leading the way with that then there is reason to be hopeful of improvemnt.

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Bin the 18z it looks all wrong in low resolution, the gfs is always slower at picking up blocking signals. Cold and blocked is the trend tonight once the heavy snow clears.

 

Admire your positivity Frosty, but I can't see what you mean- after a rather transitory cold spell it looks like we are going to pick up southerlies- indeed both the GFS 18Z and the ECM are showing air being drawn up from a long way south after the weekend. It's still a fair way out but looks the logical evolution to me as the high moves into Central Europe. Could be great for cold and snow though- if you live in Greece or the Balkans that is!

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Interesting comparisons between GFS 18z & ECM12z around T228-T240, obviously in the realm of FI, but to my untrained eye as such there does seem to be genuine similarities in the NH T500 charts depicting a amplified pattern with mid atlantic troughing and strong heights building into Scandinavia, both of which hinting to an eventual continental flow....This does sem to be something of a recurring pattern so worth noting (as more experienced posters seem to be alluding to...)

 

 

GFS T228   post-4149-0-06558900-1385939148_thumb.pn

 

ECM T240  post-4149-0-94213300-1385939209_thumb.pn

 

GFS T240 post-4149-0-90427600-1385939231_thumb.pn

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Hopefully they will change with UKMO output tomorrow. The UKMO 12z was comfortably furthest East with pattern out of all the output so unless it is leading the way with that then there is reason to be hopeful of improvemnt.

Maybe,but this was never more than a short burst Mucka.We keep the cold at the surface for a while after which seems to have always been the case.

The interest for me is after the weekend.Where does the block go-ne/se or stays around the uk?

 

A chance for a developing Scandi block is there in current modeling with the bulk of the vortex moving to Canada.

I would like to see more strength in the s. arm of the jet though to support that otherwise we may end up with something around Denmark/Germany or worse if we continue to see too much low development across S.Greenland/Iceland.

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I'm just so relieved the ukmo 12z solution has been trashed by the latest fax charts so we can now look forward to a few days/nights of arctic weather on thurs / fri and perhaps saturday. Chances of a wintry xmas period are good too according to EC32 day outlook. :- )

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I agree with Crewecold now, we have a really important opportunity if we can get near the far reaches of what FI is showing, it would take a long while to shift a block like that, if cat, I don't think I've ever seen a block as big as the one in the 18z tonight.

 

We'd have to endure southerlies for a while, but when something shifts, it would send us into the most amazing easterly which could rival any we've seen!

 

I'll write off the cold snap in exchange for far FI please weather gods?

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I just hope Monday morning sees a little upgrade or my facebook gonna look stupid , can you believe at gfs 6z this morning GFS ECM And UKMO were all agreed on a 3 day Northerly , 12 hours later the Northerly may not even happen .... grrr this model watching much more tense than last year....

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Maybe,but this was never more than a short burst Mucka.We keep the cold at the surface for a while after which seems to have always been the case.

The interest for me is after the weekend.Where does the block go-ne/se or stays around the uk?

 

A chance for a developing Scandi block is there in current modeling with the bulk of the vortex moving to Canada.

I would like to see more strength in the s. arm of the jet though to support that otherwise we may end up with something around Denmark/Germany or worse if we continue to see too much low development across S.Greenland/Iceland.

 

Yeah it was always going to be short but we were in line for a direct hit rather than a glancing blow and here in the NW that can make all the difference between heavy snow showers and no showers at all which accounts for my fixation with where the pattern sets up. I guess for those away from the NW it doesn't make much difference.

 

GFS 18z ensembles are not a pretty sight out to day 12 on the whole with a predominantly Westerly flow - just the odd run even hinting at an Easterly but given how poor GFS has been with even its ensembles flopping about I won't lose any sleep over it - for now. Posted Image

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Don't know if it is just a blip but quite a few members go with the Op including the control. Run to run consistency just hasn't been there with GFS for some time though so no way of knowing until tomorrows Euros come out.

 

http://www.meteociel.fr/cartes_obs/gens_display.php?x=252&y=84&run=18&runpara=0&type=0&ext=1

Not sure about that , but if next Thursday comes off as currently shown I will have to have egg on my face and admit the GFS was closest all along , but I suspect slight upgrades in the morning with a much more pronounced Northerly and then high pressure moving NE across the Uk setting up a Scando High that will deliver some sort of Easterly flow during week 2/3 of Dec 2013 . 

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I'm just so relieved the ukmo 12z solution has been trashed by the latest fax charts so we can now look forward to a few days/nights of arctic weather on thurs / fri and perhaps saturday. Chances of a wintry xmas period are good too according to EC32 day outlook. :- )

 

Hi Frosty

They look very much like the 12z to me with a glancing blow, blink and you'll miss it?

 

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Bin the 18z it looks all wrong in low resolution, the gfs is always slower at picking up blocking signals. Cold and blocked is the trend tonight once the heavy snow clears.

Whilst some places will see some snow, particularly over high ground in the north, heavy snow does not look likely for the vast majority of us.... probably c.95% in fact.  The 18GFS is even quicker to end the brief Arctic blast, in fact there may be no blast at all if the current trend continues across the coming 24hrs, with Fri PM already seeing a quick pressure rise from the SW.

 

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Exeter have opted for 60% blend back to 00z GM but have v low confidence in these modifications (ie to something more akin to EC & GFS). Scope of cold ingress to W a key uncertainty especially but in wider sense a raft of issues currently lead to lower confidence now versus where we sat 24hrs ago. 9/12 MOGREPS members also favoured the more progressive, less pronounced cold spell and this just emphasises further the uncertainty post-Thurs.

 

Most of the latest GEFS simply sweep the northerly away. I'd imagine that the opps should be leading the way at this range although there seems almost no consistency beyond day 4 at present.

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Not sure about that , but if next Thursday comes off as currently shown I will have to have egg on my face and admit the GFS was closest all along , but I suspect slight upgrades in the morning with a much more pronounced Northerly and then high pressure moving NE across the Uk setting up a Scando High that will deliver some sort of Easterly flow during week 2/3 of Dec 2013 . 

 

GFS would of been closest no matter what we get given it has put out every solution possible over the last few days - your face need not be eggy. Posted Image

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Exeter have opted for 60% blend back to 00z GM but have v low confidence in these modifications (ie to something more akin to EC & GFS). Scope of cold ingress to W a key uncertainty especially but in wider sense a raft of issues currently lead to lower confidence now versus where we sat 24hrs ago. 9/12 MOGREPS members also favoured the more progressive, less pronounced cold spell and this just emphasises further the uncertainty post-Thurs.

 

I don't like the sound of that at all. Seems as though there is a lot more scope for something flatter and/or further East. Ah well plenty of Winter left.

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