Model Output Discussions 12z 01/09/2016

[Ali1977]

There are many variants in this afternoons models, all however show plenty of blocking - trying to forecast beyond next weekend would be a minefield. Polar vortex however, that seems to have gone on vacation this year (so far)

[mb018538]

GFS and UKMO vary so much at 144 hours it's impossible to be certain what will happen after. As is the norm when model watching....when something so far from the norm is the prevailing pattern (and has been for quite a while now), we can expect lots of variation and a lack of consistency.

[swfc]

12z looks a dogs dinner imo.so many variables i guess but a bit of a know mans land 180 hrs plus.blocking continues but putting any meat on the bones is prob left to the more exp guys.ecm should be interesting!!!!

 

[Daniel*]

I do not think we're going to see a so called relaxation of the northern blocking with SW/ W'ly winds taking a foothold well not as we typically know. I think HLB could become entrenched and locked in for a long period of time. What I'm seeing on GFS is fairly similar to ECMWF seasonal 500mb Geopotential Height anomalies from December to February although it is late October! - I come to the opinion the models may be too easy to bowl the blocking away.

From Gavin's ECMWF seasonal model interpretation video it does reflect stark similarities. It's hard to comprehend such could persist for so long however it does depict +ve heights over Scandinavia stretching through Iceland and onto Greenland, so the tendency may be there for blocking to be form in those whereabouts and for it to stick, throughout winter 16/17. Although this idea might be far fetched - I'd expect it to ebb and flow or we would be in for a very long, cold winter which isn't out the question, but they're exceptionally rare. Perhaps one of those winters could be coming.

I've never known such an interesting October in model watching -whatever happens it's all very interesting. 

 

Edited October 18, 2016 by Changing Skies.
Tidy up

[Mucka]

ECM 144

I wonder how much the boys and girls at Exeter will modify UKMO raw output in the fax charts - it looks way out on a limb. Perhaps a little support from JMA.

Let's hope the ECM has it pegged instead. Lovely shaped Icelandic/Greenland high. 

Edited October 17, 2016 by Mucka

[swfc]

11 minutes ago, Mucka said:

ECM 144

I wonder how much the boys and girls at Exeter will modify UKMO raw output in the fax charts - it looks way out on a limb. Perhaps a little support from JMA.

tbh over the years ecm does like to over play the blocking set ups as does gfs underestimate hlb.ukmo is imo the middle ground and usually given the time frame it works in not bad.that said who nos given the current output and its meanderings!!!

[knocker]

In the 10-15 period the GEFs is in the same ball park as last night's EPS with a less amplified pattern ( i realise it tends this way in the later period) with a SW/W upper flow depending on how east the ridge/trough are

Edited October 17, 2016 by knocker

[SMU]

Awsome ECM

however unusual split -

UKMO + JMA  v GFS / ECM & GEM

on the fence for this eve....

[Ali1977]

1 minute ago, Steve Murr said:

Awsome ECM

however unusual split -

UKMO + JMA  v GFS / ECM & GEM

on the fence for this eve....

Best chart of the year so far there, some proper cold incoming of the ECM was to be believed !!!

[knocker]

The ecm deconstructs the Atlantic trough and has a deep upper low about 400Km WSW of Cornwall by 12z Sunday. Sounds familiar, The associated fronts associated with the surface low pressure are just to the west of Cornwall. What happens next?

During the rest of the run the upper low remains in situ whilst the Scandinavian HP disappears east, and the fronts and low pressure can edge NE bringing some quite strong SE winds to the UK,The HP is replaced by a cold positively tilted trough stretching down to NE Europe whilst the high pressure rebuilds to the NW of the UK.

Edited October 17, 2016 by knocker

[January Snowstorm]

ECM does look good but the continent is too warm to advect any decent cold over us. Yes cold would follow if the wind veered Northeast but for how long.

I honestly think that while the synoptics are indeed awesome the end result is cool and dry.

Much better than this time last year but when you've been burnt so many times its hard to believe this trend will continue

[Grimers]

The GFS model and the ECMWF model show a low N of the Faroe Islands bringing moderate NW winds and cool temperatures to all parts of the UK tomorrow and a high over W parts of the UK bringing light N winds and cool temperatures to all parts of the UK on Wednesday.

       

[Man With Beard]

I sense some real knashing of teeth in here tonight. That ECM would be a winter stunner in perhaps even just a few weeks time. Can the pattern really hold? Looks rather stubborn to me.

[Cloud 10]

1 hour ago, Steve Murr said:

Awsome ECM

however unusual split -

UKMO + JMA  v GFS / ECM & GEM

on the fence for this eve....

 

Nice to be on the fence so early this year...

 

Couple of ECM day 10's..

 

 

 

[Wilxy]

Evening.

Looking through the GFS and ECM tonight, there is clearly some uncertainty in how close low pressure will get to the SW.

GFS is showing spells of showery rain moving north across the country.

Also milder air moving north but with colder air never far away!

 

ECM looks less unsettled away from the SW as the block of high pressure causes the low to undercut towards Spain.

ECM also has slightly warmer uppers at the same time frame as GFS.

 

Overall its been a very interesting and unusual  October so far and that doesn't look like changing in the near future.

[knocker]

A lok at the anomalies this evening. Not surprisingly no complete agreement in the 6-10 range although they are all in the same ball park with the pattern.

The orientation combined of the Scandinavian HP and the cut off upper low to the south continues to be a problem and while this remains the case interpretation by the det. runs will throw up differences in the detail that will become a trifle magnified by day 10. NOAA and the GEFS perhaps indicating somewhat more inclement weather for a period with some quite strong SE winds but rather premature to be concerned too much with detail

Obviously lacking agreement in the earlier time frame they are not going come together in the later one

The GEFS for example still ha some positive heights over Scandinavia and Greenland with some ridging mid Atlantis and a weak trough over the UK which wouldn't be unpleasant with a rather benign W/NW upper flow. Whereas the EPS has more marked ridging into Greenland with a non anomalous trough over Scandinavia so probably the Surface high setting up shop just to the west of the UK, Again not an unpleasant scenario and one Sidney would be quite pleased with. NOAA is tending towards the GEFS but until there is better agreement confidence must be low although some of it might be a question of timing.

Just an observation but some pretty hefty WAA into N. Canada at the end of the EPS

 

Edited October 17, 2016 by knocker

[Paul_1978]

7 hours ago, bluearmy said:

The ens AO/NAO are starting to show a return to neutral/slightly above as we enter november

quite a way off but I guess exeters own models are looking this way too. 

I wouldn't be predicting a return of mobility based on what I can see on the ens data as yet though 

How accurate are NAO forecasts at that range though? November being a couple of weeks away yet...

[bobbydog]

43 minutes ago, Paul_1978 said:

How accurate are NAO forecasts at that range though? November being a couple of weeks away yet...

They are forecast to go slightly positive though, before tanking into negative. As is the mean zonal wind.

Like a deep breath before the plunge into winter...

[knocker]

Today

A band of rain should clear the SE late morning leaving most of Britain in a cooler NW airstream with showers, mainly concentrated in the north and quite windy in the east as the low runs down the North Sea.

The GFS this morning.

The low mentioned above continues SE and intensifies before settling over Germany where it's to be found 12z Friday. Meanwhile to the west HP has been ridging NE over Ireland towards the  Scandinavian high pressure so increasingly drier and settled in the west but showery and quite windy in the east.

Now to the battlefront. The Atlantic trough deconstructs to the west as has been mooted for some time and by Sunday 12z we have this position

Ergo the surface low is west of Iberia leaving the UK twixt and between the LP and the HP to the north east.

From here we are entering a new scenario with further deconstruction of the trough to the south west as it tracks south allowing once again very brief ridging but more importantly opens the Atlantic door to to new trough that arrives from the NW to impact the UK by Tuesday. Meanwhile the Scandinavian HP has retreated east. And of course with this evolution it's no coincidence that the jet has awoke. Of course whether this materialises is still very much an open question

 

 

Edited October 18, 2016 by knocker

[swfc]

After the 6z this morning and yesterdays ukmo id expect ecm shortly to show a less bullish output in regards to building heigthts towards greenland.maybe things going neutral nao wise have crept in a bit late on the ecm but still nothing zonal really in the output.

[mb018538]

You would expect the GFS to evolve into that scenario - it's way more progressive than the UKMO even by 144 hours. Most of the country has pressure 10mb lower than the UKMO run, which will of course have ramifications down the line.

[bluearmy]

Latest EC 46 much more fluid re euro heights than fridays offering. nothing dramatic on the mean re sustained cold but evidence that some cold snaps are more than feasible within a mean at a months range +.  Post 21/11 looks potentially interesting re cold for a few days. Greenland stays anomalously warm and the jet looks set to stay on a southerly trajectory  

the main point is that the run looks to promote something quite different to last November and more akin to how a late autumnal month should be

[bluearmy]

35 minutes ago, mb018538 said:

You would expect the GFS to evolve into that scenario - it's way more progressive than the UKMO even by 144 hours. Most of the country has pressure 10mb lower than the UKMO run, which will of course have ramifications down the line.

Won't happen as per the op gfs 00z but taking our eye away from our little part of the world, a pretty good hemispheric run. It's not about the n Atlantic  in late October . 

[MR EXTREMES]

11 hours ago, Steve Murr said:

Awsome ECM

however unusual split -

UKMO + JMA  v GFS / ECM & GEM

on the fence for this eve....

good call to be on the fence,

the gfs blocking vanished.

on to ecm is also looking similar no strong heights to our north garden path should of guessed it as happens nearly every year.

conclusion is return to much more mobile zonal flow.

 

Edited October 18, 2016 by MR EXTREMES

[knocker]

36 minutes ago, bluearmy said:

Won't happen as per the op gfs 00z but taking our eye away from our little part of the world, a pretty good hemispheric run. It's not about the n Atlantic  in late October . 

To be fair blue some of us do have an interest in the here and now as well as the forth coming deep freeze.