Model output discussion - proper cold spell inbound?

[bluearmy]

1 minute ago, shotski said:

Just a quick question but why do you never post these charts ? I think I know the answer in advance but just curious. 

Not allowed to

 

[ghoneym]

Tonight various 12z model output operational runs again at +144 (approx 48 hours post vortex split) JMA run not out yet but will edit post when its available. I've included the Jetstream this time also. All models attempting to show a progressive elongation of the main portion of vortex, The Azores High still prominent and not as obvious in Westward retreat or strength reduction compared to 24 hours previous.  Also Maybe a start to that SE tilt to the jet stream that Nick Sussex mentions earlier. ICON has the most prominent Pacific ridge on this run the rest retreating towards more zonal outlook from 24 hours earlier.

Overall I think today the model outlook shows typical uk wintery interchangeable conditions throughout. (this is not sitting on the fence but just how I see it) However, if a quick trop response is on the cards then we may see that change in the outlook over the next few days to an even colder and promising non typical (nowadays) wintery outlook.

ECM     UKMO      GFS   GEM                                                        NAVGEM     CMA  CPTEC    ICON                                                        GFS          GFS   

Edited February 6, 2018 by ghoneym
layout fix

[Singularity]

9 minutes ago, bluearmy said:

Extended eps lose the plot wrt to previous output and the ec 46, losing any low euro heights by the back end week 2 .......

That's most peculiar - I can't find anything in the MJO composites for P7 and P8 that would support such a trend even under a Nina background. 

That only leaves a sizeable drop in AAM as a possible explanation. Maybe feasible but only if the MJO stalls out.

This assuming that no major Arctic height rises are being indicated i.e. a lack of quick tropospheric response?

 

In which case there is the obvious question to the stratospheric experts; what mechanism could derail a quick downward propagation despite the highly supportive nature of the event onset?

Responses much appreciated as always 

 

As far as I currently understand it, such a response is rather like a switch in the model output as the forcing comes suddenly from above and initiated height rises regardless of the pre-existing pattern of highs and lows, which is in contrast to forcing from tropical factors in which it is possible to see an amplification trend in the output. So if EPS does latch on it'll be very sudden (if I have the right idea here).

 

Finally for now - having thought further about the GFS 06z and 12z runs, I believe the westward corrections next week may actually be related to additional MJO P7 forcing that GFS is making much more of than ECM for whatever reason. The QTR then kicks in somewhere in the period of days 10-12.

[on the coast]

24 minutes ago, bluearmy said:

Given their better resolution in the strat - yes. Weak neg AO on this suite at odds with the gefs and geps. I think tomorrow morning’s run will be viewed with interest in Exeter, assumig the clusters don’t reveal anything obvious.

Oh dear. Just shows how hard to get a decent cold spell is in our part of the world.

[winterof79]

11 minutes ago, on the coast said:

Oh dear. Just shows how hard to get a decent cold spell is in our part of the world.

I would not say that Blues post means that we will not benefit from the forthcoming event, but I must say it reads that way when indicating Exeter.?

When even the most learned on here post that does not mean it will happen. It seems the extended EPS lose the plot regularly.

I will take that mean for the time being

Edited February 6, 2018 by winterof79

[bluearmy]

3 minutes ago, winterof79 said:

I would not say that Blues post means that we will not benefit from the forthcoming event, but I must say it reads that way when indicating Exeter.?

When even the most learned on here post that does not mean it will happen. It seems the extended EPS lose the plot regularly.

They have been pretty consistent recently and pretty accurate too, considering their range. I wouldn’t make too much of this evenings mean output. It’s just one suite and it does show high latitude high anomolys - it’s not like its flicked to a raging pos AO/NAO combo! 

 

[Daniel*]

Beijing model monthly forecast:

High latitude blocking fairly extensive, blocking over Greenland & likewise CFSv2 certainly a signal there for the elusive Greenland high and decent cold anomalies. 

Edited February 6, 2018 by Daniel*

[winterof79]

5 minutes ago, bluearmy said:

They have been pretty consistent recently and pretty accurate too, considering their range. I wouldn’t make too much of this evenings mean output. It’s just one suite and it does show high latitude high anomolys - it’s not like its flicked to a raging pos AO/NAO combo! 

 

The mean has been running around -5 for several runs which I know is no indication of deep cold from the East.What are you saying the MET will have to review Easterly tendency ? 

Edited February 6, 2018 by winterof79

[MattStoke]

Doesn’t currently appear to be much in the model output to back up the MO forecast of low pressure systems ‘bumping’ into the cold air, stalling and bringing snow from what I can see? This week at least it looks too marginal for snow away from high ground from these systems, with the colder air following in behind and the risk of wintry showers.

[Bricriu]

3 hours ago, nick sussex said:

Yes!  Now that the models are latching onto a QTR I’d expect that to be accelerated.

 

Excuse my ignorance, but what is a QTR?

[bluearmy]

2 minutes ago, winterof79 said:

The mean has been running around -5 for several runs which I know is no indication of deep cold from the East.What are you saying the MET will have to review Easterly tendency ? 

the run, in it’s latter stages looks quite different to what had become consistent low anomolys to our south in the extended. The met will not review their output based on one run if mogreps And glosea are consistent. If the 00z extended eps are similar in promoting the Azores ridging ne into France is end week 2, then perhaps they will be having some second thoughts 

[Yarmy]

1 minute ago, Bricriu said:

Excuse my ignorance, but what is a QTR?

Quick Tropospheric Response. 

[syed2878]

qtr quick  Drop response 

[comet]

Apart from very cold perhaps bitterly cold weather on the way ( Feb 91 cold ) there is great potential for plenty of snow to I would have thought if the trop comes anywhere close to replicating what we are seeing in the strat. Any cold and snow prior to the 20th down here in the south is a bonus I think.

I would imagine by the end of the weekend we should have a very good idea exactly what lies in store for Europe and the UK with just the finer details to sort out. This one should be very much worth the wait.

[Don]

10 minutes ago, bluearmy said:

the run, in it’s latter stages looks quite different to what had become consistent low anomolys to our south in the extended. The met will not review their output based on one run if mogreps And glosea are consistent. If the 00z extended eps are similar in promoting the Azores ridging ne into France is end week 2, then perhaps they will be having some second thoughts 

Lets hope this isn't the start of the outlook going belly up!!  It's about time we had some luck!!

[Uncle Gargy]

So it's all going wrong?

[Met4Cast]

Just now, Uncle Gargy said:

So it's all going wrong?

Ha, no. 

It's one run at the extreme end of the model runs. The stratospheric warming hasn't happened yet, the models are going to flip backwards and forwards quite a few times in the next few days I suspect.

[comet]

I wouldn't be  concerned with what the eps are showing like any model and runs they have plenty of off days. Some people do like to fret.

[markw2680]

6 minutes ago, Uncle Gargy said:

So it's all going wrong?

I’d imagine it will be the weekend before things become a little clearer although I’m sure there will be many ups and downs to come as usual ?

[tight isobar]

Well by 18z gfs a much better profile..

Remember the 180 hrs!! -mark point-..

And still 10hpa tagging along nicely...op run!!

Edited February 6, 2018 by tight isobar

[blizzard81]

59 minutes ago, bluearmy said:

They have been pretty consistent recently and pretty accurate too, considering their range. I wouldn’t make too much of this evenings mean output. It’s just one suite and it does show high latitude high anomolys - it’s not like its flicked to a raging pos AO/NAO combo! 

 

I don't quite share your lauding of the ecm. I have found it to be very fickle these past couple of years in the long term forecasts especially. It has highlighted blocking in all the right places for the uk at week 3 only for these forecasts to be nothing more than a false dawn. It can be anything but consistent. For instance, look at last night's week 3 and 4 ecm update compared to the ec 46 update of today  you mentioned. They sound very different by all accounts. The trouble I find though is that when the ecm switches to a milder outlook for the UK it is nearly always on the money! 

[blizzard81]

7 minutes ago, tight isobar said:

Well by 18z gfs a much better profile..

Remember the 180 hrs!! -mark point-..

And still 10hpa tagging along nicely...op run!!

I don't like the look of that 150 chart. The azores is starting to stick it's nose in a little more! 

Edited February 6, 2018 by blizzard81

[doghouse]

1 hour ago, winterof79 said:

The mean has been running around -5 for several runs which I know is no indication of deep cold from the East.What are you saying the MET will have to review Easterly tendency ? 

Classic seasoned netweather poster..... when the Siberian express is getting out of control apply the brakes a tad and when it gets unbearably grumpy ramp the cold. Manages / heightens expectations and keeps the traffic moving. Smoothly

[bluearmy]

6 minutes ago, blizzard81 said:

I don't quite share your lauding of the ecm. I have found it to be very fickle these past couple of years in the long term forecasts especially. It has highlighted blocking in all the right places for the uk at week 3 only for these forecasts to be nothing more than a false dawn. It can be anything but consistent. For instance, look at last night's week 3 and 4 ecm update compared to the ec 46 update of today  you mentioned. They sound very different by all accounts. The trouble I find though is that when the ecm switches to a milder outlook for the UK it is nearly always on the money! 

The eps only go to T360 ???

[tight isobar]

3 minutes ago, blizzard81 said:

I don't like the look of that 150 chart. The azores is starting to stick it's nose in a little more! 

really!!??..this is the 180..azhp flat...and dieing a death...with the pv...-latter frames?!l