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Paul

The hunt for cold - Model discussion (late November)

Paul

If you're hunting for cold potential in the model output, this thread is for you. But if you'd like to look more widely at the models, please head over to the general model discussion thread.

This is a model related thread, so a general, frequent theme of the model output is a given, but it will not be strictly enforced:

  • Some topic drift, humorous responses etc are fine
  • Posts likely to lead the thread off on an entirely off topic tangent are not ok. For example (but not solely limited to): Posts entirely or mainly about Met Office, BBC or media forecasts with little or no model context, and posts solely asking for a weather forecast in a specific location.
  • Posts which start with something like 'I know this is off topic but ...' are not ok.
  • Posts which break the forum guidelines are not ok (eg trolling, troll-hunting, weather guilt tripping, overly defensive/aggressive, abusive, disrespectful to others)

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Given that the 'experts' have already ditched their expectations, for a front-loaded winter, for the very opposite, I'll not be writing-off anything...

Anwho, here's the T+126 chart:

Netweather GFS Image

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1 minute ago, Ross Andrew Hemphill said:

Potential for some snow in Scotland this weekend on the GFS 12z, down to about 300m so definitely one to watch in the next few days! ❄️ 

A few runners 
gfs-0-90.png?12gfs-1-96.png?12gfs-0-126.png?12gfs-1-126.png?12

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23 minutes ago, Shaftesbury Snow said:

Just to clarify again.

A back loaded winter means cold - blocked - snow in the second half of winter. I referred to a major pattern change going in to mid to late Jan onwards. I posted this morning charts to back this up...please take a look. I also called zonal up to 144hrs on yesterdays 12z GFS.

I definitely did not rule out any cold in December , however I did say any cold wont last long in December and would probably be transient and weak. There wont be the major patter change just yet though that will happen in January based on the attached. There will be attempts at it though as the NH profile is out of sync.

To anyone else who is referring to my posts please quote them as you will see they are quite different to what is being said.

Does this now make it clearer? I think you have also contradicted yourself there. Please quote where you think I said things and I will happily clear up any confusion 🙂 

The links - Canadian model from dec to feb and then JMA dec to feb

 

 

cansips_Dec.png

cansips_Jan.png

cansips-Feb.png

JMA Dec.png

JMA Jan.png

JMA Feb.png

 

Unfortunately many posts have been deleted from yesterday so the contentious posts no longer remain.

I have absolutely no issue with what you have posted above or other posts that state any cold in December will be short lived, it is unusual to get sustained cold of more than a few days anyway in England.

If that was all you said yesterday then people would not of asked you to clarify.

What you are clarifying above is that you are going with the seasonal models for strong blocking later in Winter. 

It is fine to post them as evidence you see a blocked second half of Winter and predominantly zonal December based on those models but it isn't really day to day MO discussion since seasonal models tell us little about when or if a pattern change is going to happen or how our weather will look in a couple of weeks.

As for confusion, you seem somewhat confused as to what I asked you which was whether you thought we would see a pattern change or not in the time-frame specified and not whether you took seasonal models as gospel.

 

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7 minutes ago, Ed Stone said:

Given that the 'experts' have already ditched their expectations, for a front-loaded winter, for the very opposite, I'll not be writing-off anything...

Anwho, here's the T+126 chart:

Netweather GFS Image

And which of these experts have ditched a front loaded forecast?? Not seen any do that myself??

Cheers

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GFS still building pressure to the South just when we don't need it so harder to get the Atlantic ridge we will need to take advantage of blocking away to the NE

gfsnh-0-144.png?12

UKMO still more promising but not ideal.

UN144-21.GIF?27-17

If the output continues on these lines it looks more like we will get a slow build to a mid lat block to begin any pattern change.

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27 minutes ago, frosty ground said:

image.thumb.png.4653257d4c1fd7b59a4650a518f12090.png

 

Don't see it because it's not there, see heights to the south (Blue) , but the mean flow is south westerly (red).

Your interpretation is literal but the mean slp is never ever going to verify - if you assume the Scandi high solution will, then that mean would clearly have an easterly drift based on those mean heights 

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1 minute ago, Mucka said:

 

Unfortunately many posts have been deleted from yesterday so the contentious posts no longer remain.

I have absolutely no issue with what you have posted above or other posts that state any cold in December will be short lived, it is unusual to get sustained cold of more than a few days anyway in England.

If that was all you said yesterday then people would not of asked you to clarify.

What you are clarifying above is that you are going with the seasonal models for strong blocking later in Winter. 

It is fine to post them as evidence you see a blocked second half of Winter and predominantly zonal December based on those models but it isn't really day to day MO discussion since seasonal models tell us little about when or if a pattern change is going to happen or how our weather will look in a couple of weeks.

As for confusion, you seem somewhat confused as to what I asked you which was whether you thought we would see a pattern change or not in the time-frame specified and not whether you took seasonal models as gospel.

 

To be honest Im not here to make enemies - when I wrote the below post yesterday it was exactly in context with other discussions at the time such as blocking etc

"      On ‎26‎/‎11‎/‎2018 at 16:18, Shaftesbury Snow said:

GFS keeping things mild up to 144hrs

The pattern is unlikely to change until late January in my opinion based on all of the long range models and the fact that we are continuously chasing FI"

I definitely don't take long range models as gospel but I also observe sun spot predictions, look out for SSW, MJO and lots of other things. I think many others on here today are now following the idea of a pattern change (blocked and cold) into January.

Much of the talk on this thread has not been about day to day models and many have spoken about the bigger picture etc. No one else has been slated today for saying similar to me. Maybe they have better reputations and people don't want to offend them. My previous post to this is exactly what I said and I stand by that.

If you follow the day to day models for the hunt for cold it will drive you mad, I just look for tends and broader NH profiles and the day to day models have moved away from a blocking scenario at the moment going into December.

Anyway, apologies to any offence caused to anyone

 

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6 minutes ago, sebastiaan1973 said:

Oops. Going for COD. So several days in phase 8. We have to wait and see what the effect is.

ensplume_full.gif

Zero assistance from the MJO to Atlantic amplification I would have thought.

Edited by mountain shadow

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7 minutes ago, sebastiaan1973 said:

Oops. Going for COD. So several days in phase 8. We have to wait and see what the effect is.

ensplume_full.gif

That’s the bias corrected gefs Sebastian... other models mostly keep it outside though without big amplitude 

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5 minutes ago, bluearmy said:

That’s the bias corrected gefs Sebastian... other models mostly keep it outside though without big amplitude 

Okay. Thanks!

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12z mirrors Exeters musings, mild wet and windy followed by a quieter interlude then back to Atlantic dross ..

 

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24 minutes ago, bluearmy said:

Your interpretation is literal but the mean slp is never ever going to verify - if you assume the Scandi high solution will, then that mean would clearly have an easterly drift based on those mean heights 

I would say the high would be centered over Spain, buts that my interputation. 

Almost like the 12z run

gfs-0-276.png?12

This run has a slight easterly drift but only for a day or so.

Edited by frosty ground

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1 minute ago, northwestsnow said:

12z mirrors Exeters musings, mild wet and windy followed by a quieter interlude then back to Atlantic dross ..

 

Not within the next two weeks NWS? 

The monster low at T300 won’t exist like that in any case so the run beyond the sceuro ridge is likely nonsense 

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3 minutes ago, northwestsnow said:

12z mirrors Exeters musings, mild wet and windy followed by a quieter interlude then back to Atlantic dross ..

 

Which forecast period? 5-15 or 15-30?

No model hits the 15-30 day period 

The end of the GFS shows the High from the east pushing west in the last few frames.

I think you need to stop comparing every runwith the METO or BBC musings.

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Just now, bluearmy said:

Not within the next two weeks NWS? 

The monster low at T300 won’t exist like that in any case so the run beyond the sceuro ridge is likely nonsense 

The Atlantic appears to be easing through the gears Blue..

Im a bit puzzled as to the driver though.. no monster PV , no massive temp gradient ES, zonal winds hardly through the roof?

 

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3 minutes ago, frosty ground said:

Which forecast period? 5-15 or 15-30?

No model hits the 15-30 day period 

The end of the GFS shows the High from the east pushing west in the last few frames.

I think you need to stop comparing every runwith the METO or BBC musings.

Im not comparing every run matey.. the trends over the last 48hours are consistent with a westerly Atlantic pattern, and this ties in with Exeters musings..

 

Edited by northwestsnow

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2 minutes ago, Mucka said:

Thanks. I am just trying to figure out where you are coming from.

So yes the bolded part does strongly suggest you were dismissing any idea of a pattern change does not?

You have to consider how seasoned posters are going to take that after they have just posted their thoughts on how and why they see a pattern change.

it seems dismissive and not based on any current model output for the period being discussed.

I don't think there has been any hostility toward you, just strong disagreement with that sentiment an dhow it was expressed.

As I said previously it is fine to put up seasonal models and longer range ideas on occasion but the meat and potatoes of this thread is analysis of the daily output with the understanding it chops and changes but attempting to pick the bones out of it.

Once we get blocking and the prospect of snow things become focused on shorter term still - just a natural progression for cold and snow lovers.

Posting seasonal model output for Jan Feb is not argument for how you see December.

The weather will and does make fools of anyone forecasting beyond a few days but there is still a lot of experience and skill that goes into interpreting the daily output.

Personally I still think we will see a pattern change which is what you seemed to be writing off - I could well be wrong but for now I believe the weight of evidence suggests that.

You have now elaborated upon your position to sate you consider any longevity of blocking will occur in second half of Winter and any blocking first half will be short lived which is welcome and hopefully you see how that is not contentious and people will not pull you up on it.

There is of course no need to apologise and I'm sure you weren't trying to upset people.

We are all weather enthusiasts here and as such a family, a family that squabbles a lot but still a family 😄

Look forward to your future thoughts.

 

 

I appreciate that and points well made.  

I don't think there will be a pattern change in December as such, not a lasting one, but my gut feeling is that it will start to take place after new year and set us up nicely. Unfortunately I don't really see much cold until then. I would love to be proved wrong though big time!

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4 minutes ago, northwestsnow said:

The Atlantic appears to be easing through the gears Blue..

Im a bit puzzled as to the driver though.. no monster PV , no massive temp gradient ES, zonal winds hardly through the roof?

 

I think u maybe answering your own question there northwestsnow. The jet fires up way to much, the GFS will underestimate the the impact of the negative AO. More and more eye candy will crop up in the next 3/4 days

 

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6 minutes ago, northwestsnow said:

The Atlantic appears to be easing through the gears Blue..

Im a bit puzzled as to the driver though.. no monster PV , no massive temp gradient ES, zonal winds hardly through the roof?

 

It’s the cold pool over NE America causing the jet stream to power up over the Atlantic and the heights over Iberia not helping things either!

E9B35184-9D1A-4224-8C8E-C98EBFE0E0C8.png

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Front loaded Winter to Back loaded winter to Zero loaded winter we need SSW to save us this year i'm afraid and what good is MJO diagram if they change daily like the models??

ensplume_small.gif

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Op runs a bit meh tonight, so far, firs few decent options developing in the GEFS though, pick probably P7, here at T240:

image.thumb.jpg.51737d15bc2222f6862e019abb09932c.jpg

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17 minutes ago, booferking said:

Front loaded Winter to Back loaded winter to Zero loaded winter we need SSW to save us this year i'm afraid and what good is MJO diagram if they change daily like the models??

ensplume_small.gif

As BA pointed out earlier, that is the bias corrected version, use this..

.40AE0A2E-12C8-48E1-88A1-29AD743A8353.thumb.gif.ad81defa60599746d4d69fb41d2b234a.gif

Low amplitude but scraping round the edge at least.

As for your comment. Eh? On that basis, what is the point of any weather chart?? The MJO will change in the same way as any computerised weather chart changes, every time  new ‘start data’ gets entered. 

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I Think the GFs(p) will lift the mood in here shortly. It’s actually showing some consistency now if you compare it to it’s 6z run 

AC8E62D8-945A-40AE-9CDD-80773503AC18.png

56394932-5064-4077-B27D-C0CE6CFE3BBA.png

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