Model output discussion - The Hunt For Cold

[Skullzrulerz]

11 minutes ago, Steve Murr said:

You keep looking in the wrong place - 

The models are resolving the forward speed of the pacific jet at 120 & how much angle the advection takes up towards greenland in the following 24 hours -

The UKMO / FV3 / GEM create enough vertical motion to ensure the high develops in situ over Greenland - the ECM doesnt

it has nowt to do with what you keep referring to - 

All 06 suite ( bar 06 operational) are more amplified at 120 - the 06z mean / the JMA / FV3

Ive added a picture. - so assuming the more amplified angle works the blue area of PVA dropping south will start forcing your spoiler shortwave back east-

Follow it on the Fv3 & GEM

* remember ECM is the least accurate model @ day 6 currently *

 

Through that is true and hopefully this time around the ECM is wrong in this case 

 

However what can not be denied is this deep cold / Greenland has been going going and gone 

[blizzard81]

7 minutes ago, bluearmy said:

Possibly but this is such a delicate evolution that I doubt it makes a lot of difference

good to see the model being consistent if nothing else

going back to the eps cluster, whilst I don’t see it’s important for that 30% to grow, I do think we need the op to at least jump over to it for one run over the next 3 outputs 

I disagree. We really do need to see that percentage grow. However, yes it would be nice to see an ecm op which doesn't act like the grinch. 

[Bullseye]

Seems both GFS and ECM are struggling with the NE Pacific, surely this playing a part in the downstream which makes this upcoming pattern more delicate in current runs? 

 

[SMU]

ECM T2Ms show the milder blip as debilt tows a SE wind then a sharp drop off- with cold air from the NE- note the control

 

 

[SMU]

Just now, Bullseye said:

Seems both GFS and ECM are struggling with the NE Pacific, surely this playing a part in the downstream which makes this upcoming pattern more delicate in current runs? 

 

Yes as mentioned above regarding the pacific jet - The + EPO BIAS means to flat ....

[shaky]

3 minutes ago, Steve Murr said:

Yes as mentioned above regarding the pacific jet - The + EPO BIAS means to flat ....

Seen the gfs parallel mate!!even better than the 00z run!!block into greenland and cold wave coming in from the north east!!

[Derecho]

06z swingometers tell you all you need to know about the output. Downgrades all round with temperatures pretty close to average (hence the description of non-descript for temperatures). I'd say only two or three of the ens members look capable of producing a decent northerly looking at the output on November 25th.

So the outlook is this:

- A rather chilly easterly developing but its borderline stuff whether its cold enough for any snow to fall

- In a nutshell though it will be dull and chilly

- The retrogression MAY fail because of a few things: From left to right here is the analysis of what went so wrong on the 00z

1)   2)  3) 

1) Remember that energy that was initially forecast to go under the block, well now its forecast to go up to Greenland carrying the cold air with it.

2) The high with the warm uppers then struggles to make it westwards

3) Any cold air over Europe passes through the UK leaving no energy under the block and causing it to sink. 

I have a few concerns at the moment, firstly the situation around us is changing. Arctic sea ice has recovered very well over the past week and its low sea ice extent IMO that helps promote meridional jet stream patterns. Here is a graph of the extent:

The other concern is where all the cold air is pouring out to. Just look at this global temperature anomaly plot. All the cold air is pouring into NE Canada right where we don't want it. This could serve to fire up the North Atlantic jet. Also look at the anomaly pattern over the North Atlantic in the region I highlighted this is absolute classic positive NAO structure for winter months.

Furthermore history isn't on our side. El Nino years tend to have a positive December NAO and these type of winters seem to be backloaded. Out of all the El Nino's (of varying strength) since 1950 here are the Decembers with a positive NAO:

Positive: 1951, 1972, 1979, 1982, 1986, 1991, 1994, 2004, 2006, 2014, 2015

Neutral: 1957, 1987, 1997, 2003

Negative: 1963, 1968, 1969, 1976, 2009

So there we go, I think if we want to go down the same route as 2009 we need to damage the vortex earlier and I believe this is an oppurtunity that needs to be taken. With the cold air stockpiling over NE Canada the Atlantic is at risk of firing up again and if it does we will be stuck in a rut. We do have low solar acitivty but we also did in the early 1910s and those winters were poor. IMO the main thing that catches my eye is the unfavourable Atlantic SST pattern developing.

If we got cold air over Europe some resistance could be put up against the Atlantic but if there isn't and the North Atlantic jet does fire up its not going to have much to stop it IMO.

Happy to be proven wrong although the long range output is also swinging the other way compared to yesterday.

Please let the GFS parallel be right.... please lol

Edited November 17, 2018 by Quicksilver1989

[BLAST FROM THE PAST]

53 minutes ago, DanBaynes said:

 

 

@BLAST FROM THE PAST would you and @chionomaniac both be thinking along the same lines?

I don’t know but Wouldn’t be a bad thing to listen to Chiono when it comes to pressure pattern responses.

 

BFTP

[Mike Poole]

FV3 at T240, is this the last Narnia run on this particular chase, or is this the correct evolution?

Given that the yes/no Greenland high point is at T120, I think we'll have a good idea this evening, and it will be decided for sure on the 0z runs tomorrow...

Edited November 17, 2018 by Mike Poole

[karlos1983]

That’s a stonking Control run on De Bilt ENS toward the end. 

Lets hope we can see a decent det run on the 12z and get more members joining the cold clustering! 

 

[Met4Cast]

The GFS Para is either going to have a spectacular climbdown or it’s going to become one of the best models on the planet. 

It’s been incredibly consistent, 12z runs will hopefully give us a signal forward either way! Lots to still be hopeful about

[Summer Sun]

JMA in it's extended range which only runs to t264 once a day on the 12z goes for high pressure to our east keeping the UK chilly but keeping the real cold air further east

Edited November 17, 2018 by Summer Sun

[SMU]

6 minutes ago, Daniel Smith said:

The GFS Para is either going to have a spectacular climbdown or it’s going to become one of the best models on the planet. 

It’s been incredibly consistent, 12z runs will hopefully give us a signal forward either way! Lots to still be hopeful about

Supported by UKMO 00z ( as far as I can gather from the 168 chart )

 

[bluearmy]

4 minutes ago, karlos1983 said:

That’s a stonking Control run on De Bilt ENS toward the end. 

Lets hope we can see a decent det run on the 12z and get more members joining the cold clustering! 

 

The eps control plays out the Atlantic trying to push against blocking to the n/ne ......de bilt is colder than the uk but the uk is right in the battleground with snow line moving south to north (ebbing and flowing).

lookign through the gefs gives a decent mean but the individual members are less wonderful (save a few)

those predicted euro low heights are proving unreliable ......twas ever thus .......

 

 

[coldwinter]

Not sure i agree with @Quicksilver1989 post above, sure cold spilling down into the eastern states can fire up the jet, but it can easily be part of a negative NAO pattern it just means the jet stream has to be amplified, plus the temperature graphic is based on the 6z GFS, which even then most certainly doesn't show anything zonal and still shows a weak and fragmented jet with intermittent ridging northwards. The key thing as Steve said is the jet to be amplified enough early doors coming off the states to pump our Greenland high up. Still lots of uncertainty! 

[swfc]

1 minute ago, Steve Murr said:

Supported by UKMO 00z ( as far as I can gather from the 168 chart )

So do you see things moving in the rite direction ie cold from the north east? Tia.

[Derecho]

1 minute ago, coldwinter said:

Not sure i agree with @Quicksilver1989 post above, sure cold spilling down into the eastern states can fire up the jet, but it can easily be part of a negative NAO pattern it just means the jet stream has to be amplified, plus the temperature graphic is based on the 6z GFS, which even then most certainly doesn't show anything zonal and still shows a weak and fragmented jet with intermittent ridging northwards. The key thing as Steve said is the jet to be amplified enough early doors coming off the states to pump our Greenland high up. Still lots of uncertainty! 

Yes cold air over the Eastern US can be part of a negative NAO pattern just like in December 2010 however cold air over Newfoundland almost always isn't associated with a -NAO. December 2010 for example was very cold over some parts of the Eastern US yet many mild temperature records were smashed over Newfoundland during that same month.

[Devonshire]

19 minutes ago, Quicksilver1989 said:

06z swingometers tell you all you need to know about the output. Downgrades all round with temperatures pretty close to average (hence the description of non-descript for temperatures). I'd say only two or three of the ens members look capable of producing a decent northerly looking at the output on November 25th.

I really do like visual presentations of trends - such as this. Am I correct in thinking this shows the distribution of gfs ensembles into your categories? If so, I would wager that a few on here might be interested in such presentations for other models - especially the gfs parallel! I guess similar information can also be gleaned from cluster images that are posted on a run by run basis, but I like this presentation of trends.

[Decemberof2010]

28 minutes ago, shaky said:

Seen the gfs parallel mate!!even better than the 00z run!!block into greenland and cold wave coming in from the north east!!

And now it seems we have some backing for this from the MO. Now mentioning ‘small chance of even colder weather arriving with northerly winds’ on their further outlook

[Derecho]

11 minutes ago, Devonshire said:

I really do like visual presentations of trends - such as this. Am I correct in thinking this shows the distribution of gfs ensembles into your categories? If so, I would wager that a few on here might be interested in such presentations for other models - especially the gfs parallel! I guess similar information can also be gleaned from cluster images that are posted on a run by run basis, but I like this presentation of trends.

Yup that is correct, the GFS parallel is also included. I'd love for ECM ensembles to appear on WZ! As that would be really valuable information but they aren't available there unfortunately.

[Methuselah]

6 minutes ago, Decemberof2010 said:

And now it seems we have some backing for this from the MO. Now mentioning ‘small chance of even colder weather arriving with northerly winds’ on their further outlook

Indeed. And when the MetO see something in their model-reading (and from the vast amount of expertise and experience, at their disposal) I take extra note...Not that that's any guarantee, of course!

[SMU]

19 minutes ago, swfc said:

So do you see things moving in the rite direction ie cold from the north east? Tia.

I think some interpretations are easily lead by the ECM op ( & GFS op )

I think the swing in the 12s this afternoon will be quite telling - 

remember we used to say no cold spell unless UKMO on board -

Well its on board --- looking for big cold swings at 330pm

[nick sussex]

A good GFS06 hrs run because it doesn’t phase the low near the UK with low pressure in the Atlantic .

I think this is now becoming the bellwether for moving forward . It’s the phase tragedy on the ECM which signifies a less favourable upstream pattern .

 

[Derecho]

Just now, Steve Murr said:

I think some interpretations are easily lead by the ECM op ( & GFS op )

I think the swing in the 12s this afternoon will be quite telling - 

remember we used to say no cold spell unless UKMO on board -

Well its on board --- looking for big cold swings at 330pm

Fingers crossed you are right, if we do get an arctic northerly the GFS parallel deserves a lot of credit as its stuck pretty resolutely with it over the past few days. El Nino winters with a negative December NAO tend to see blocking persist for further into the winter. 1939, 1968 and 2009 are all classic examples, hope we can get such an elusive pattern for this winter too.

[Devonshire]

7 minutes ago, Quicksilver1989 said:

Yup that is correct, the GFS parallel is also included. I'd love for ECM ensembles to appear on WZ! As that would be really valuable information but they aren't available there unfortunately.

Ah, ok - I wonder if there is an easy way of distinguishing the parallel run from the others - indicating which category it is in, to see its trends alongside the other trends?