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Model output discussion - proper cold spell inbound?


Paul

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Posted
  • Location: Leeds
  • Weather Preferences: Bitter Cold in winter and Extreme heat in summer
  • Location: Leeds

If the GEFS aren't improved from the 0z then I'm starting to be concerned. If we have such a significant SSW happening, can someone explain why the GFS op has lost the blocking on its last 2 runs?

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Posted
  • Location: North Somerset
  • Location: North Somerset
22 minutes ago, mb018538 said:

Here is your culprit...

gfsnh-0-6.png?6?6gfsnh-1-6.png?6?6gfsnh-5-6.png?6

There has been a pool of very cold air stuck over NE Canada for ages...850s down to -40! This pours off the eastern seaboard, meets milder air from the south, tightens the thermal gradient, fires up the jet, and we are left with cold NW'erlies. Rinse and repeat.

Indeed. Put perfectly. Seems that will be how February pans out unless something significant suddenly changes.

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Posted
  • Location: Banbury
  • Location: Banbury
34 minutes ago, mb018538 said:

Well the 6z GFS is another epic fail and just keeps things mainly zonal and unsettled. Let's hope the ECM is on the right track.

I agree and that was my point very early this morning , the blocking idea from GFS ( OP) has drifted away.....................lets see the ENS to make a proper judgement

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Posted
  • Location: Essex Riviera aka Burnham
  • Weather Preferences: 30 Degrees of pure British Celsius
  • Location: Essex Riviera aka Burnham

CFS 1 monthly modelling (yes you may laugh) has hardly been strong on any blocking either, a few runs showed GH/Scandi HP about a week ago but seen little since. The reason I posted this is back in March/April 2013 which I believe was the last SSW event was largely the first to pick up on the signal in the modelling and was pretty steadfast after that.

Edited by Froze were the Days
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Posted
  • Location: uxbridge middlesex(- also Bampton oxfordshire
  • Weather Preferences: blizzard conditions. ice days
  • Location: uxbridge middlesex(- also Bampton oxfordshire
1 minute ago, Banbury said:

I agree and that was my point very early this morning , the blocking idea from GFS ( OP) has drifted away.....................lets see the ENS to make a proper judgement

Exactly...revert to ens' - and take operationals after 108..as a pinch of salt.

Massive dynamical confusion after that point.

The oven at the pole throwing chaos, and mixing up data points!!

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Posted
  • Location: South Norwood, London
  • Weather Preferences: Snowy Cold Winters & Warm Dry Summers
  • Location: South Norwood, London
17 minutes ago, Decemberof2010 said:

If the GEFS aren't improved from the 0z then I'm starting to be concerned. If we have such a significant SSW happening, can someone explain why the GFS op has lost the blocking on its last 2 runs?

I would guess because the SSW hasn't actually happened yet so the models are predicting what may or may not happen based on the available data. When there can be for example stark differences in temperatures / precipitation  and wind speed for within a few miles of 2 locations imagine how many different outcomes of weather are possible for our small island the further ahead we look? At day 10 the permutations must be huge.

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Posted
  • Location: Orpington Kent
  • Weather Preferences: Snow freezing rain heat waves
  • Location: Orpington Kent

I think everyone needs relaxs a bit here what I have seen with gfs it goes with full guns blazing with blocking then loses the signal then brings it back  blocking signal to a nearer time frame..

Edited by abbie123
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Posted
  • Location: uxbridge middlesex(- also Bampton oxfordshire
  • Weather Preferences: blizzard conditions. ice days
  • Location: uxbridge middlesex(- also Bampton oxfordshire

Make of them what you will!??.

6zlondon ens..

Good viewing in my book...@trending @correctly

MT8_London_ens (4).png

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Posted
  • Location: Essex Riviera aka Burnham
  • Weather Preferences: 30 Degrees of pure British Celsius
  • Location: Essex Riviera aka Burnham

...and the ECM follows a day or so on from earlier GFS output whilst then GFS goes on a different tangent. Another theme of this winter. Really not sure if the ECM has been that reliable...

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
2 minutes ago, Daniel Smith said:

There's a bit of negativity with regards to the models this morning so lets try and clear a few things up. 

The SSW is currently underway, the first signs of warming are appearing over Canada

Strat1.thumb.png.ea765be645fcaf045774475564463cca.png

By Tuesday, we're at this point. SSW reached.

Strat2.thumb.png.fbc2a1afdee8f793e81c09414c3edbfc.png

Until the SSW has fully happened, the models are effectively "guessing" what the effect of the warming will be. When the warming is in full motion they'll start to get real time data about it fed into them and this should snowball into more consistent runs, at the moment Shannon Entropy is high and we're seeing a lot of run to run variations. The good news is that despite these variations, there's a lot of suggestions of blocked weather, albeit the details with where the blocks set up is up for grabs. The ensembles show this quite well

ENS.thumb.png.d872b4b9447f63141190abf31370adbb.png

There's a massive amount of scatter in the mid-term but if you look at the very end of the run, a majority of the ENS memebers are on the colder size (just 2 members above freezing) and the mean is readily dropping. 

The control run of the GFS seems to be the most consistent at the moment out of it and the OP, continuing to show blocked weather to our North.

5a7d88dce3a67_GFSControl.thumb.png.aa4be1a673625715e9eed6d19f1d1f40.png

The ECM this morning was also a very good run

ECM.thumb.gif.bb6bf8a35b2a9183f16fa21e02c44760.gif

The EPS whilst not the coldest in the world, also show more clustering towards the colder solutions with the mean ever so slightly dropping away towards the end of the run. Note the overnight GFS was on the warmer side

5a7d89824b5e8_ECMEnsembles.thumb.gif.d2c469dec92c516a82377f5eade5ce6c.gif

So for those saying "the ensembles aren't improving" or that "the GFS has dropped the blocking", I'm not entirely sure what models/ENS suites you're looking at, but the ones I'm looking at are very much trending towards a blocked scenario.

Whether that means cold for the UK and snow IMBY I don't know. At this stage it's about looking at trends, seeing just how warm the stratosphere gets and in tern how quickly we see a trop response to that. At this early stage I'd put a 50% chance of the UK becoming cold, 30% chance of deep cold and a 20% chance of no cold at all. 

We're in a good place. Trends are going our way. Sit back and relax, don't take ANY output literally, it's going to be volatile and all over the place. Look for broad consistency, i.e is there blocking somewhere to the North of us, and the answer over the last 10-15 runs or so has been yes.

 

And, in addition, we (meaning humanity) do not fully understand the myriad feedbacks that immediately follow an SSW...I agree 100%: the enormous amount of model variance is telling us all more than we can get our heads round, I think...? At least, I can't get my head round it!:D

Perhaps we're heading for a 1975-like Spring? Which wouldn't be too bad, would it?:cold:

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Posted
  • Location: G.Manchester
  • Location: G.Manchester
14 minutes ago, TEITS said:

How on earth you can come to that conclusion is beyond me considering the vast differences we are currently seeing in the model output. May I ask why you are discounting what this mornings ECM is showing?

I would like to know too because, what with the massive uncertainty resulting from a very significant SSW event (and the probable subsequent propagation through the atmos layers down to the tropos) how anyone, even the proper experts, can unequivocally make a statement like that. Strikes me as a bit strange.

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Posted
  • Location: Morden, Surrey.
  • Location: Morden, Surrey.

Forgive me for the sake of this thread but has this ssw occurred yet? 

Has the dismantling of the pv happened yet and has it given us a clear insight of where blocking will occur owing to this ssw?

I don’t think so..

There have been some great posts from insightful scientific posters over the past few days who has backed up their thoughts with understandings and data related to strat warming’s and how it can and possibly will affect our island in the near future. I duly note that not many of the charts posted by our knowledgeable posters actually show a ecm or gfs chart but more scientific charts related to the ssw and what goes with it.

That may be the clue to those less knowledgeable like myself regarding what’s happening up top and that is because nothing has occurred yet and hence the reasons why the filtering down to the likes of the daily models have yet to get to grips.

So to avoid more bickering why not wait until the ssw has happened then ramp or moan in the relevant thread? 

Early next week imo likely to see where we go in the mid to long term.

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Posted
  • Location: Gillingham, Kent
  • Weather Preferences: Snow, Thunderstorms,
  • Location: Gillingham, Kent
3 minutes ago, frosty ground said:

I asked the other day but why can the models not resolve the SSW when the same models are predicting a SSW.
 

It's not quite as straight forward as that. There are so many different variables that will impact the response we see, the timing of the troph response to the warming etc.. that if anything, the SSW is just an added complication for the models to try and determine the outcome. 

Imagine you have a handful of sand and you drop it, even though you're the one dropping the sand, you have no idea where the individual grains will land.

Edited by Daniel Smith
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Posted
  • Location: Bournemouth
  • Weather Preferences: Dry mild or snow winter. Hot and humid summer.
  • Location: Bournemouth
3 minutes ago, frosty ground said:

I asked the other day but why can the models not resolve the SSW when the same models are predicting a SSW.
 

Predicting a cup of coffee(warming) is going to be spilt is not the same at predicting where the coffee will run to. Cold and blocking.

Edited by That ECM
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Posted
  • Location: North Somerset
  • Location: North Somerset
20 minutes ago, TEITS said:

How on earth you can come to that conclusion is beyond me considering the vast differences we are currently seeing in the model output. May I ask why you are discounting what this mornings ECM is showing?

Comment related to 6z output. Thats what it showed. Maybe should of added: 'going by the 6z output...' Lots of panicing and jumping on posts again it seems.

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

IMO, it's rather like deciding to kick someone in the goolies. And easy enough decision...What's more difficult, however, is assessing their likely response!:shok:

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Posted
  • Location: Bournemouth
  • Weather Preferences: Dry mild or snow winter. Hot and humid summer.
  • Location: Bournemouth
5 minutes ago, Chevron12345 said:

 Lots of panicing and jumping on posts again it seems.

Indeed, why don't you try not to and let it unfold:D

Edited by That ECM
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