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Model output discussion - into Christmas


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2 hours ago, mb018538 said:

Not sure I agree with unsettled - maybe the far NW closest to the low, but most of England and Wales only expected to see 0-20mm rain over the next 10 days.

Yes I missed off the following sentence, so thank you for pointing the miss out.

'The further NW one lives then the more unsettled and the further SE the less unsettled.'

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Hi gang, sorry I'm not posting at the moment, my dad is seriously ill so I'm sure you will understand. Looking at the latest models, nothing particularly wintry on offer but we all know that can soon

Right folks, due to family commitments and a lot of travelling, that's me over and out till the end of the year... So i would just like to wish each and everyone of you a fabulous Christmas, to those

Hi  We all hear ya - its horrible when your a traditional winter weather lover hoping for snow - especially when the kids are desperate for it as well. Thats what makes the chase so exciting

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7 minutes ago, Steve Murr said:

All these posts & only one man following the right model-

Another opportunity to examine the UKMO v GFS / ECM scenario.

UKMO 144 > 168 cold uk circa -8c into England

GFS / ECM flat as a pancake. ( but GFS & ENS slowly amplifying )

As usual pointless following the endless mean charts being posted for day 8/9/10 waste of time when amplification occurring at day 6..

All eyes on the UKMO 12z ...

To be fair Steve it’s the model output discussion not the ukmo output discussion. Some of us did post the ukmo at t144 this morning ? 

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6 minutes ago, Steve Murr said:

All these posts & only one man following the right model-

Another opportunity to examine the UKMO v GFS / ECM scenario.

UKMO 144 > 168 cold uk circa -8c into England

GFS / ECM flat as a pancake. ( but GFS & ENS slowly amplifying )

As usual pointless following the endless mean charts being posted for day 8/9/10 waste of time when amplification occurring at day 6..

All eyes on the UKMO 12z ...

Yes and no Steve - short term momentum injection and consequent wave breaking can make a mockery of mean charts BUT those mean charts (when read alongside teleconnective analysis) and cluster projections give a sense of the likelihood of the sustainability of the pattern or the possibility of a pattern change. UKMO may well be accurately picking up on a mid Atlantic wave break...but the broader pattern suggests it will create a transient burst of colder uppers at best.

I guess it depends what readers and analysts are hoping for. I have next to no interest in a single day of cold or colder conditions - delivers nothing for the SW. Unless the duration of the pattern is going to be 3 days at the very least then it isn’t really going to impact with any significance.

In that context the bigger picture tools certainly have their uses.

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Oh. What's occurring?

Haven't felt I had much to post over Christmas, what with the output being the way it was.  Of course it is much welcome for a dryer outlook, I'm not denying that at all. But no sign of a colder snap or spell in the heart of winter.  Now the GSDM charts seem to be unavailable, we look to the MJO, latest plots, GEFS, ECM and GEM:

image.thumb.jpg.e83d8b8307da668e732ecd536f58a0b1.jpgimage.thumb.jpg.8a15ae551b08acfe6ef9b55759976497.jpgimage.thumb.jpg.213c0e723c7a966cb7267c2e88b012a0.jpg

As so often once the MJO becomes part of the narrative, the predicability of it by the models goes AWOL.  The GEM ensembles look particularly ridiculous. We can hope for a bit more of a progression into phase 7, maybe, which might aid a more amplified pattern here in due course.  

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1 minute ago, nick sussex said:

Sadly the UKMO hits the buffers .

Flatter than this mornings run . The GFS was a touch more amplified than the early 06 hrs run but nothing to write home about .

We await the ECM with trepidation ! 

UKMO isn't great but its better than the GFS!!

We might even see a frost on UKMO ...

 

 

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8 hours ago, carinthian said:

Morning all.Of all the models this morning , the UKMO gives the best hope for some colder weather in the period 144t -192t . The extended chart below out to 168t pushes the cold front through much of the British Isles with some much colder airmass promised for the NE of Scotland, possibly deep enough for snow showers. Also better positioning of the Atlantic high which appears to not allow as much energy on the Northern Arm as compared to GFS. We will see if this trend continues, hopefully.

C

 

ukm2.2020010400.168.lant.troplant.prp.fcst.gentracker.png

Following from the above observation , it would appear that the UKMO run in the short /medium term at 144t brings a much colder air mass into the British Isles with coldest uppers into NE Scotland as shown in the chart below. In all honesty the latest 500mb flow chart would indicate this cold to be only transient. However, the UKMO run continues to dig a sharper trough to the east that again differs from the very flat GFS runs at this time..  I think during the next few days we will soon develop curve ball lows which develop and move at a pace around the high pressure . Eventually, I think a flow from NW to SE could eventually predominate by day 10. Just my thoughts.

untitled.png

Edited by carinthian
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P14 goes from flat to awesome in 2 days, or is that a swing that has no chance of happening around that time ?

2E899E45-01C3-4B3F-AA72-04DFFD5258E7.png

F6F73607-35C5-4C4A-97D7-90388337B4BA.png
 

Actually P14 is a sustained freeze, 6 days later it’s still v cold 

36AF6016-8EAF-4EFA-8EC2-639F2A0DD839.png

Edited by Ali1977
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GEM looks most amplified at 144 and there is a trough over Iberia which means although the run looks uninspiring its actually very cold at the surface-

image.thumb.png.05f4c56e2879853ec893decf44b431a4.png

168 dews

image.thumb.png.17fcbca30647996560ddb593e241b09c.png

192 dews

image.thumb.png.28f2b679784d74f8c7c496d178350b22.png

240 dews

image.thumb.png.75ab7376efd64c97e99b41d8312fef2a.png

The trough over Iberia

image.thumb.png.53a3574faec71a498bcbf9f5752cc37c.png

Edited by northwestsnow
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Outlook is mostly dry and settled for England and Wales more unsettled for Scotland and Northern Ireland although even here some dry days at times and mild by day and night at first. 

1673012536_EUROPE_PRMSL_RAIN_108(2).thumb.jpg.7541d5e3471fb62438ba73b45d8a49c1.jpg

1908856378_EUROPE_PRMSL_RAIN_126(3).thumb.jpg.897db452a11d973c73ffa1697539b59f.jpg

1298048218_EUROPE_PRMSL_RAIN_186(2).thumb.jpg.640219378b98aeafb6a0eab2e21056b6.jpg

High pressure mostly dominant for central and southern areas with only brief interuptions to this with weakening bands of rain fizzling out to give drizzly and misty conditions but winds will turn more westerly which will give more breaks in the cloud than we've had recently come the new year. 

A more detailed look tomorrow.  ?

Edited by jordan smith
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17 minutes ago, carinthian said:

Following from the above observation , it would appear that the UKMO run in the short /medium term at 144t brings a much colder air mass into the British Isles with coldest uppers into NE Scotland as shown in the chart below. In all honesty the latest 500mb flow chart would indicate this cold to be only transient. However, the UKMO run continues to dig a sharper trough to the east that again differs from the very flat GFS runs at this time..  I think during the next few days we will soon develop curve ball lows which develop and move at a pace around the high pressure . Eventually, I think a flow from NW to SE could eventually predominate by day 10. Just my thoughts.

untitled.png

Just looking at the NH profile you can see that the probability of any ridge sustaining is extremely low: for the UKMO (forgetting its D6 tendency to over-do ridges):

255471207_UN144-21(2).thumb.gif.60c573599817fbe3558d797575581245.gif Compare GFS>1326426781_gfsnh-0-144(1).thumb.png.8b019e4a16baa9a601472e71393cd619.png

We can extrapolate the likely following-dynamics, as the main features are common. So with the GFS post D6:

anim_czc0.gifGem messier, but ditto: anim_uif6.gif

That tPV chunk is just circulating to our north captured by the wedge/high on the opposite side of the NH. Not sure that it is even possible to avoid a flattening of the pattern? Unless the Arctic high is wrongly modelled or we get some tropical forcing, the tPV will follow the mechanics of the air flows.

After about D10 we see the Arctic high slide towards Canada on the GFS op which allows the tPV to access the euro/Asia regions and hence why we see the potential for height rises in our sector. Unfortunately on the 12z just a return to the mini-ridge (topple) ridge-trough combo though I suspect that future runs will flip-flop between that and maybe more pronounced ridges, latterly more-so if we get a Pacific ridge. All well into the future and hard to be enthused for the next 12 days plus!

 

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Winter lovers chart of the day from the Canadians for next weekend. Little support from the other models for this temporary depth of cold from a sharp trough over Northern France to produce some snowfall. Of all the main models . possibly UKMO comes closer but with a more shallow trough and flatter high.

 C

winteroverview_20191228_12_168.jpg

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10 minutes ago, northwestsnow said:

Quite a snowy and cold 18z into FI...

Probably different in the morning ...

I've noticed a garden path emerging from the 11 onwards. Even a scandi high a couple runs back

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9 minutes ago, CanadaAl said:

I've noticed a garden path emerging from the 11 onwards. Even a scandi high a couple runs back

Yeah I’d say that path is getting bigger again but tbh after the last week or so of very poor charts at least it’s something a bit better to see, you never no it might be on to something, doubtful but you just never no. Can you imagine this place if it follows on tomorrow and then the other models also start to follow it....mmmm

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