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Model output discussion - late November

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2 minutes ago, CreweCold said:

All that slight bit of transient amplification is doing is allowing a more seamless rise in pressure across Europe in the longer run. We will not get enough amplification to promote a Scandi high so it's pointless. 

As a result, ECM ends as bad as you could get, with the jet roaring away well to our N and a strong Euro HP. As +NAO as you could get!

At least with the jet angled more NW to SE at a lower latitude, we were in the game for some PM outbreaks. 

Tbh I've never known an Atlantic ridge cause so much excitement but what ever floats your boat!!! Yes the PV still looks like producing a fair amount of rain etc,not welcome

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7 minutes ago, CreweCold said:

All that slight bit of transient amplification is doing is allowing a more seamless rise in pressure across Europe in the longer run. We will not get enough amplification to promote a Scandi high so it's pointless. 

As a result, ECM ends as bad as you could get, with the jet roaring away well to our N and a strong Euro HP. As +NAO as you could get!

At least with the jet angled more NW to SE at a lower latitude, we were in the game for some PM outbreaks. 

Look at the image above and the profile over Canada and the States- it's completely flat, combined with the vortex located over that area...that is not a good combination going forward.

Yes I was actually making the same point re ECM, as I said finger up from the vortex, not to it.

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8 minutes ago, swfc said:

Tbh I've never known an Atlantic ridge cause so much excitement but what ever floats your boat!!! Yes the PV still looks like producing a fair amount of rain etc,not welcome

Me neither, that was the point I was making yesterday. 

Steve often touches on the AO index and record low values etc. However, looking at the latter stages of the ECM, we'd be seeing some extreme +NAO values more than anything else. We shouldn't be shocked at this, the seasonals have sign posted this very well for 2-3 months.

I touched last year on the fact that very mild Decembers tend not to be a good omen for cold Januaries (given obvious stray examples of course). Got slated for saying it last year but it turned out to be the case. We run the real risk of a mild December again this year, unless we can pull the Euro high far enough N to allow frost and fog across S UK.

Edited by CreweCold

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1 minute ago, Mike Poole said:

Yes I was actually making the same point re ECM, as I said finger up from the vortex, not to it.

I know, I was just embellishing the point 🙂

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14 minutes ago, CreweCold said:

All that slight bit of transient amplification is doing is allowing a more seamless rise in pressure across Europe in the longer run. We will not get enough amplification to promote a Scandi high so it's pointless. 

As a result, ECM ends as bad as you could get, with the jet roaring away well to our N and a strong Euro HP. As +NAO as you could get!

At least with the jet angled more NW to SE at a lower latitude, we were in the game for some PM outbreaks. 

I agree, apart that it is an ECM D9 chart which has nominal chance of verifying there is simply no amplification in the NH to sustain any HLB, as you say, at best a topple. We really need, at the bare minimum a Pacific ridge, but the background noise is contrary to a Rossby wave synoptic. 

The GFS Control, D8-D16: anim_tbf4.gif

The above does sum up the main cluster of the GEFS, a zonal, maybe cold at times flow, possibly fledgling Atlantic ridges that flatter to deceive, so maybe colder air as the lows spin through. Hoping that this changes, but as of today's GFS output, after the cold high, zonal looks the most likely. Of course, tomorrow is another day and the usual caveats...

Edited by IDO

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6 minutes ago, CreweCold said:

Me neither, that was the point I was making yesterday. 

Steve often touches on the AO index and record low values etc. However, looking at the latter stages of the ECM, we'd be seeing some extreme +NAO values more than anything else.

I touched last year on the fact that very mild Decembers tend not to be a good omen for cold Januaries (given obvious stray examples of course). Got slated for saying it last year but it turned out to be the case. We run the real risk of a mild December again this year, unless we can pull the Euro high far enough N to allow frost and fog across S UK.

Well I'd be a tad surprised if the December CET is milder than average by lets say December 10th - judging by these ensembles

image.thumb.png.015a3b42721c7661f082dcc9e37d2b8a.png

First 5 days look very cold and below average - a warm up thereafter but then mild air looks very far away.

I'd personally be a tad surprised if the December CET came out over 0.5'C above average 

There are now a good considerable bunch of ensembles that show a cool down after the warm up - with the ensemble average below average (and this continues until the end of the suit). Granted - virtually all of these colder ensembles are seeing just a standard polar maritime influence from the NW/WNW as opposed to a more potent cold spell (at this stage anyway).

 

Edited by StretfordEnd1996

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8 minutes ago, CreweCold said:

All that slight bit of transient amplification is doing is allowing a more seamless rise in pressure across Europe in the longer run. We will not get enough amplification to promote a Scandi high so it's pointless. 

As a result, ECM ends as bad as you could get, with the jet roaring away well to our N and a strong Euro HP. As +NAO as you could get!

At least with the jet angled more NW to SE at a lower latitude, we were in the game for some PM outbreaks. 

Look at the image above and the profile over Canada and the States- it's completely flat, combined with the vortex located over that area...that is not a good combination going forward.

I appreciate what your saying but your taking a 240hr chart and saying that it will depict the weather going forward.

The part in bold?? are you able to accurately predict this?

The whole point of watching the charts is to make educated guesses and try to provide evidence of why you have chosen them exactly as Steve has done.

If it does not come off then at least he has provided a reasoning to why.

For example I have taken the ECM from the 16th and posted the 240Hr chart below

1218512886_ECM24016th.thumb.png.02721c91151d6b4b12b91d9bfee3a42d.png

Now If I had said to you at this point that we would end up with a Greenland high you'd have written it off as fools gold.

But here is todays chart.

1273641559_ECM26th.thumb.png.49403e79c8249827db82f0c1a011c354.png

Completely different as yet again the PV remains on the Siberian side where as it was previously modelled to move back.

I am not saying that we aren't in for a zonal spell nor am I saying that the cold wont continue but with regards to the trough digging into Europe and the Scandy high becoming a player surely it cant be written off till the event has occurred.
 

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1 minute ago, StretfordEnd1996 said:

Well I'd be a tad surprised if the December CET is milder than average by lets say December 10th - judging by these ensembles

image.thumb.png.015a3b42721c7661f082dcc9e37d2b8a.png

First 5 days look very cold and below average - a warm up thereafter but then mild air looks very far away.

I'd personally be a tad surprised if the December CET came out over 0.5'C above average 

There are now a good considerable bunch of ensembles that show a cool down after the warm up - with the ensemble average below average (and this continues until the end of the suit). Granted - virtually all of these colder ensembles are seeing just a standard polar maritime influence from the NW/WNW as opposed to a more potent cold spell (at this stage anyway).

 

Experience tells me that maybe 80% of the time, cold zonal is moderated to standard zonal- it's just a thing that happens wrt the modelling. Either troughing doesn't dig as far S or the polar jet energy is modelled poorly.

It's not a given by any means, but my point is once you start getting +ve heights in towards Europe, you run the risk of a SW'ly Atlantic pump setting up...

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The ext EPS not dissimilar to the GEFS so I'll skip the waffle

ecmwf-ensemble-avg-nhemi-z500_anom_5day-5979200.thumb.png.189703395bf70b56568f84d5495815b5.pngecmwf-ensemble-avg-nhemi-t850_anom_5day-5979200.thumb.png.ec7abc433c68e5b221702349de0c9a65.pngecmwf-ensemble-avg-eur-t2m_c_anom_5day-5979200.thumb.png.72dfa854918aea15269e1bcc30815d4a.png

The current Atlantic SST anomalies

cdas-sflux_ssta_atl_1.thumb.png.a2525fcfc8e757c4c5b5d4c14a48fc25.png

Edited by knocker

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3 minutes ago, CreweCold said:

Experience tells me that maybe 80% of the time, cold zonal is moderated to standard zonal- it's just a thing that happens wrt the modelling. Either troughing doesn't dig as far S or the polar jet energy is modelled poorly.

It's not a given by any means, but my point is once you start getting +ve heights in towards Europe, you run the risk of a SW'ly Atlantic pump setting up...

Thus let's not remember that's completely expected at this time of year (a zonal pattern) 🙂

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1 minute ago, CreweCold said:

Experience tells me that maybe 80% of the time, cold zonal is moderated to standard zonal- it's just a thing that happens wrt the modelling. Either troughing doesn't dig as far S or the polar jet energy is modelled poorly.

It's not a given by any means, but my point is once you start getting +ve heights in towards Europe, you run the risk of a SW'ly Atlantic pump setting up...

I think to be honest though this winter could be different in that regard, with a solar min even if we got a winter without any HLB, i think we might still get a lot more winds off the Atlantic with a more NW component in them and troughs digging into Europe than usual, still would be disappointing and might mean areas further South still see no snow at all of course.

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16 minutes ago, ALL ABOARD said:



The part in bold?? are you able to accurately predict this?


 

To an extent, yes. Reasonable confidence. Let's not forget, we work in terms of probabilities here.

If you employ a dynamic method I.e model output analysis + experience, you can get a decently confident prognosis.

In this instance, very little evidence for any Scandi HP around day 8/9/10 in ANY modelling. This is allied to the fact that from a hemispheric perspective, there is currently no forcing for a sustained HLB that will benefit us in terms of cold. Consolidation of the TPV around the Canadian/Greenland locale looks to rule out Greenland heights going forward and we have little Pacific amplification to play with. 

Low Greenland heights correlate with higher pressure across Europe, and that's what we are increasingly seeing modelled.

On to your other point, I don't know how much more reasoning you want me to give. A spade is a spade.

Edited by CreweCold

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ECM ensemble mean at T240:

image.thumb.jpg.36c783037d878d268290b2ba3bed30f3.jpg

Oh well, only 5 days until winter ends, sorry, starts...

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Just now, Mike Poole said:

ECM ensemble mean at T240:

image.thumb.jpg.36c783037d878d268290b2ba3bed30f3.jpg

Oh well, only 5 days until winter ends, sorry, starts...

Yet some people will argue that the further outlook isn't dire...

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7 minutes ago, feb1991blizzard said:

I think to be honest though this winter could be different in that regard, with a solar min even if we got a winter without any HLB, i think we might still get a lot more winds off the Atlantic with a more NW component in them and troughs digging into Europe than usual, still would be disappointing and might mean areas further South still see no snow at all of course.

I'm on that page too Feb, it's the baseline I'm hoping something will allow us to build from, and I guess that means a SSW, but we'll see.

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The met office's forecast has changed for mid month and beyond. It's gone from mild to cool, unsettled weather. Looks good for Scotland's ski resorts. No deep freeze on the cards. Charts like this do tend to be trending:

image.thumb.png.67f3262740ae19354073b499835ed597.png

Edited by LRD

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1 minute ago, CreweCold said:

Yet some people will argue that the further outlook isn't dire...

Let's just give it a couple of days or so - we can't expect the models to constantly show a cold spell otherwise what would be the point in following the models.. it'd just get boring!

GFS for example in the longer term at +240 hours - I am in the opinion that from here if something like that were to come off it could go anyway - there's every chance those heights could push back up to the North again and form a more organised block, but also a chance that they could built to the South as part of a Euroslug...

image.thumb.png.5b35a05a23e3fc907ac641c62c1487e0.png

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5 minutes ago, CreweCold said:

Yet some people will argue that the further outlook isn't dire...

Don't get me wrong CC, I'm throwing in a small flannel, not the whole towel!

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First decent CFS for a while FWIW.

image.thumb.png.fdb4225cc1ecc31f573ee4e663f60dc6.png

image.thumb.png.d9f56d7707bc9f9c34fc0b5c8d0dec29.png

image.thumb.png.916fd332563300fc18e31967961d8014.png

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Just now, feb1991blizzard said:

First decent CFS for a while FWIW.

image.thumb.png.fdb4225cc1ecc31f573ee4e663f60dc6.png

image.thumb.png.d9f56d7707bc9f9c34fc0b5c8d0dec29.png

image.thumb.png.916fd332563300fc18e31967961d8014.png

CFS? My god, it's worse than I thought!!

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2 minutes ago, Mike Poole said:

CFS? My god, it's worse than I thought!!

🤣🤣🤣 Well it's something to look at and I guess it's possible!!!

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4 minutes ago, feb1991blizzard said:

First decent CFS for a while FWIW.

image.thumb.png.fdb4225cc1ecc31f573ee4e663f60dc6.png

image.thumb.png.d9f56d7707bc9f9c34fc0b5c8d0dec29.png

image.thumb.png.916fd332563300fc18e31967961d8014.png

Anomaly charts - I don't like them. They're misleading. That first chart is showing relatively weak high pressure anomalies, which considering the 'normal' pressure readings up there are very low, says to me that it will just be slightly weaker low pressure than normal. Yet, with all those reds, it looks like a high pressure fest up there. 

The February chart is slightly more encouraging although it could be showing a west-based NAO

I guess they are better than they have been, though, as you say

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Just now, LRD said:

Anomaly charts - I don't like them. They're misleading. That first chart is showing relatively weak high pressure anomalies, which considering the 'normal' pressure readings up there are very low, says to me that it will just be slightly weaker low pressure than normal. Yet, with all those reds, it looks like a high pressure fest up there. 

The February chart is slightly more encouraging although it could be showing a west-based NAO

I guess they are better than they have been, though, as you say

No, they are 850's Its an Easterly packed December (admittedly quite dry at times but no doubt there would be enough snow to make it a stonker in places)

Here is the link for the whole run.

WWW.METEOCIEL.FR

Meteociel propose le modèle deterministe GEM

 

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9 minutes ago, CreweCold said:

Yet some people will argue that the further outlook isn't dire...

CC. Slow undercutting moving low pressure systems with modest chilly air is imo the worst outlook at the moment, the current outlook is really not too bad if your after drier and colder weather. 

The northerly has been toned down slightly admittedly but high pressure toppling in will give some parts cold frosty and sunny weather which I will accept if there is no cold and snow on the way. The only question mark will be that undercutting low for Saturday and just how for north it gets, knowing our luck it probably will end up too far northwards which will result in yet again dull cloudy and at times wet weather. 

As we all know the outlook can change back quickly so nothing should be written off and but nor should there be any time frames when it might get cold  with snow either. All we know is that for the vast majority there is no snow on the horizon. 

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Nothing quite like some deep FI cold to warm the cockles of the heart! Plenty of colder options from the GFS 12z moving forward... I certainly don't see a bang on very mild zonal set up at this stage... That could all change of course, but it's not the worst case scenario so far... Expect upgrades before much longer folks... Inside Info... 😂

gens-0-0-372.png

gens-0-1-372.png

gens-3-0-384.png

gens-7-0-336.png

gens-7-1-336.png

gens-10-0-324.png

gens-10-1-324.png

gens-11-0-384.png

gens-12-0-348.png

source.gif

Edited by Mattwolves

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