Model output discussion - 5th December 2016 - Into Winter we go

[Daniel*]

 

It's all a bit gobbledygook to me... so someone do enlighten us all. But this is good, one thinks  some atmospheric juice being thrown into the circulation....

@Tamara you are most kind  

Edited December 13, 2016 by Changing Skies

[feb1991blizzard]

1 minute ago, Changing Skies said:

 

It's all a bit gobbledygook to me... so someone do enlighten us all. 

But this is good, one thinks  some atmospheric juice being thrown into the circulation....

Good although would like to know more, from what I remember, the East Asian +ve mountain torques are best and a lot of full on SSW's followed those in the past, if you notice on the strat charts the big warmings start off coming around Eurasia Eastwards then into the heart of the vortex so would the red line actually be more likely to deliver if it shot up?

[bluearmy]

06z para very zonal (relative to what we've seen)

Edited December 13, 2016 by bluearmy

[feb1991blizzard]

5 hours ago, Weathizard said:

What makes the GFS Para produce charts like this yet the OP/control never sing from the same hymn sheet? Seen this several times in recent weeks where the GFS P has produced the goods meanwhile the standard model shows the normal dirge.

Its effectively a different model now as they are probably well into the process of tweaking, its the same reasons the GFS is always different to the ECM, certainly at stupid FI anyway.

[nick sussex]

I think the current odds do favour something more zonal but before then there is the issue of whether this will be the normal energy over the top sinking the high or whether we'll see any energy disrupting se.

The models all agree on the PV and its associated low heights  to the north but there is still a chance we might see the jet angling more ne to the north which could allow pressure to hold near Svalbard.

Theres still some uncertainty with the shortwave circled red as to whether this will just track south or whether it can edge more sw under the high, the GFS 00hrs run had a better jet cut back sw'wards and we saw what a difference that made at least initially, below is the GFS 06hrs run which wasn't as good but you can still see that key shortwave.

 

 

 

[Singularity]

Observed MJO signal finally booking it toward the Pacific, yet all the models have done is become even more confused, albeit with the Pacific still broadly in the sights of all but ECM. What with a decent convective envelope building in the far-W Pacific now, I wonder if the effect of the TC over India is being overdone. 

 
Modified/Bias Adjusted versions of ECM ens. and GEFS offer yet more different outcomes, the latter particularly striking.

However, in all projections we're lacking a signal for a full on propagating MJO signal. I expect that means we'd only see 'nudging' of the patterns toward ones favouring HLB rather than dramatic changes. 

  

To +93 hours, GFS has a very slightly sharper trough in the Atlantic and a bit more of a jet diving south to Europe which may lead to a stronger Euro trough. Can these small adjustments change our fortunes back to a chilly continental flow for later next week? I'm not holding my breath but I don't think it's moved out of reach just yet.

[Frosty.]

As for the models, the general rule of thumb for the rest of december is for a nw / se split with the most unsettled conditions for the northwest and the best of the fine weather further southeast.

 

Edited December 13, 2016 by Polar Maritime
To snip deleted quote.

[johnholmes]

As to the models and giving an attempted reasonabley scientific view.

The form model is probably best shown by the anomaly charts. Mind you even these are far from convincing over the past few days. NOAA, as usual, is perhaps the most consistent. An upper ridge predicted to be centred around southern Norway would tend to give a surface flow from somewhere east of south over the Christmas period. How cloudy will be the question and thus how cold at night. The surface models will 'eventually' give more insight into this but not for a few days yet.

links

http://www.cpc.noaa.gov/products/predictions/610day/fxus06.html

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Edited December 13, 2016 by Nick L
Non-model posts now deleted

[Seasonality]

Maybe lower pressure on the Iberian peninsula and the shortwave Nick alluded to is sliding more slowly South West than making a steep southerly dive on the previous run?

 

Edited December 13, 2016 by Seasonality

[Dennis]

Gem model 12z today good building 

[warrenb]

How can the Meto and GFS be so different even at 144

 

GFS 

 

Meto

 

[Singularity]

  

Interesting; the trough arrived a bit faster but this has actually served to retrograde the Azores ridge, while the broader trough over Europe has helped the ridge to hang on during this process.

This re-arrangement depletes the thermal gradient across the Atlantic, with the jet slackening off in the following frames;

The game's not up yet, not by a long shot. 

[tight isobar]

Expansion of eastern block and favorable' pin-point hight on 12z ..so far ..this is the pivatol point rest December. ..

[Singularity]

 

06z on the left and 12z on the right. That's quite the adjustment in jet angle. Faced with a split jet, GFS is opting to take a shortwave on the northern route of course, but I'm skeptical of that choice. Things would get very interesting if the SE trend in jet angle was to continue but it does feel like we're up against it a bit.

[swebby]

10 minutes ago, johnholmes said:

mods can we PLEASE have ALL the non model posts deleted?

As to the models and giving an attempted reasonabley scientific view.

The form model is probably best shown by the anomaly charts. Mind you even these are far from convincing over the past few days. NOAA, as usual, is perhaps the most consistent. An upper ridge predicted to be centred around southern Norway would tend to give a surface flow from somewhere east of south over the Christmas period. How cloudy will be the question and thus how cold at night. The surface models will 'eventually' give more insight into this but not for a few days yet.

links

http://www.cpc.noaa.gov/products/predictions/610day/fxus06.html

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Hi John,

A quick Q please in regards to these NOAA anomaly charts - what is the actual base line they use?  Eg, are the height anomalies measured against a rolling seasonal value, an averaged value from the past x days, a nominal global height for 500mb, etc?

Cheers S

[johnholmes]

Just now, swebby said:

Hi John,

A quick Q please in regards to these NOAA anomaly charts - what is the actual base line they use?  Eg, are the height anomalies measured against a rolling seasonal value, an averaged value from the past x days, a nominal global height for 500mb, etc?

Cheers S

hello S

I am not sure if it is a rolling seasonal or monthly value, but assume it must be something like this. Others may be able to give you their answer.

John

[Seasonality]

The high is proving to be a more resilient beast on this run.

 

[Paul]

Matt's latest synoptic guidance blog is online:

http://www.netweather.tv/index.cgi?action=news;storyid=7837;sess=

And for those looking for a bit of a snow fix, take a look at Jo's blog about her recent trip to Lapland where temperatures fell to -28c!

A trip to Lapland; Snow, Ice and -28c

[Dancerwithwings]

11 minutes ago, Seasonality said:

The high is proving to be a more resilient beast on this run.

 

Yes! GFS at h192...BLOCK....Where will this lead us....?

Edit....Will be a place both wonderful and strange :-)

Edited December 13, 2016 by Dancerwithwings

[Southender]

3 minutes ago, Dancerwithwings said:

Yes! GFS at h192...BLOCK....Where will this lead us....?

Just a shame we cannot nudge it a few hundred miles further NW. Still a more encouraging output at least. Baby steps and all that.

[tight isobar]

Nice 'arc' of heights northern Scandinavia. 

Need some sharpness there as Canadian pv lobe migrates out of its home!!!...

Still lots on here atm.

[knocker]

10 minutes ago, Dancerwithwings said:

Yes! GFS at h192...BLOCK....Where will this lead us....? will be a place both wonderful and strange :-)

Quite likely

[mb018538]

Not really sure what to make of the UKMO 144 hour chart tonight....I've got a bit of a sinking feeling though. I think the vortex/trough is going to disrupt things enough to make it mainly unsettled here.

[blizzard81]

4 minutes ago, mb018538 said:

Not really sure what to make of the UKMO 144 hour chart tonight....I've got a bit of a sinking feeling though. I think the vortex/trough is going to disrupt things enough to make it mainly unsettled here.

I agree. The beast from the east is no match for the beast from the north west - again!

[knocker]

I notice, en passant, that the  GFS opens negotiations with the cut off upper low to the south which weakens the renewed NE ridging of the Azores and allows the the main trough to make it's move.

Edited December 13, 2016 by knocker