Model Output Discussions 06z 04/11/16

[feb1991blizzard]

Just now, Frosty. said:

There is strong support from the GEFS 6z for a cold shot later next week with some ensembles wanting to prolong it into the following week by way of reloads and even increase the potency..

Not sure of its potency, hardly any ensembles if any at all dip below -5c throughout the whole run for the boundary between W.Yorkshire and Lancashire.

[Frosty.]

5 minutes ago, feb1991blizzard said:

Not sure of its potency, hardly any ensembles if any at all dip below -5c throughout the whole run for the boundary between W.Yorkshire and Lancashire.

When I say potency, I mean more of a Northerly component / Arctic influence rather than just polar maritime, anyway I've shown them above, some are better than others in terms of duration and strength. Scotland would naturally be coldest with a NW / Nly airflow.

Edited November 12, 2016 by Frosty.

[feb1991blizzard]

1 minute ago, Frosty. said:

When I say potency, I mean more of a Northerly component / Arctic influence rather than just polar maritime, anyway I've shown them above, some are better than others in terms of duration and strength.

Ok. True although the reason we prefer a more arctic component is because usually they provide colder uppers.

[Frosty.]

39 minutes ago, feb1991blizzard said:

Ok. True although the reason we prefer a more arctic component is because usually they provide colder uppers.

It could still upgrade since it's still at least 5 days away and very much an evolving situation. The experts say it's likely to turn significantly colder later next week.

Edited November 12, 2016 by Frosty.

[Hocus Pocus]

Off  topic I know but where's knocker? I miss his posts even if he's a mildie at heart he does give some much needed balance amongst those of us just looking for cold.

[swfc]

huge change on the 12z from the 6z at 144 hrs. the nhp totally changed and atlantic high flatter.very volatile output indeed!!!

 

[Mucka]

The models seem to have little idea of what will develop upstream behind our trough with the angle of the jet and amount of amplification fluctuating wildly. Easiest route to blocking and cold would probably be a ridge with low pressure diving SE in the Atlantic which would give us some cut off heights around Iceland and allow for the Russian high tor retrogress and join forces. Not much appetite for that, though ECM has had a little sniff at it, but then not much support for anything else either. 

[Frosty.]

Early next week looks mild according to the Gfs 12z with tuesday very mild indeed with 15c 59f so somewhere could top 60f on tues, the driest and brightest weather likely across the south.

[Ravelin]

5 minutes ago, swfc said:

huge change on the 12z from the 6z at 144 hrs. the nhp totally changed and atlantic high flatter.very volatile output indeed!!!

 

 

5 minutes ago, Mucka said:

The models seem to have little idea of what will develop upstream behind our trough with the angle of the jet and amount of amplification fluctuating wildly.

Not a bad match between the GFS & UKMO at t144, but as usual the GFS is making much more of the low coming off Canada, which it then rapidly intensifies.

  

[Jonan92]

My feeling is that the main difference comes from some kind of energy from the Gulf. It seems that in the 12Z run from the GFS an unmarked low goes from the Gulf to Canada and interacts with the polar low, making it intensify rapidly

 

 

 

[Ravelin]

5 minutes ago, Jonan92 said:

My feeling is that the main difference comes from some kind of energy from the Gulf. It seems that in the 12Z run from the GFS an unmarked low goes from the Gulf to Canada and interacts with the polar low, making it intensify rapidly

Whatever is causing it, the difference by t192  between the GFS 6z and 12z (and it's predecessors to be honest) is so huge it's laughable. Anything after around day 5 or 6 I'd currently treat with a pinch of salt huge enough to melt the Greenland icecap. I think the best we can safely say for the moment is we'll get something coming from a more northerly direction around day 5, but how that then develops is up in the air.

Edited November 12, 2016 by Ravelin

[Ravelin]

OK, despite what I said above, I'll post the t300 chart, just for a laugh....

IS that a big 2 fingers to all us model watchers?

[Frosty.]

The Gfs 12z brings winter to Scotland!

Ice days

Edited November 12, 2016 by Frosty.

[swfc]

16 minutes ago, Ravelin said:

OK, despite what I said above, I'll post the t300 chart, just for a laugh....

IS that a big 2 fingers to all us model watchers?

it looks like it at the end of the run.only place in the nh after the pv is smashed in the mild air is the uk!!!!! haha

 

Edited November 12, 2016 by swfc

[blizzard81]

I really do hope that uncertainty past day 6 is true as the operationals have been very disappointing thus far today. We need a stonking ecm run tonight to lift the spirits.

[Mucka]

15 minutes ago, blizzard81 said:

I really do hope that uncertainty past day 6 is true as the operationals have been very disappointing thus far today. We need a stonking ecm run tonight to lift the spirits.

Never fear, FI is here! 

 

 

Edited November 12, 2016 by Mucka

[Polar Maritime]

A few posts have had to go missing, Sensible discussion only please, Thanks.

Edited November 12, 2016 by Polar Maritime

[Connor Bailey Degnan]

Some excellent charts there in FI

[Geordiesnow]

From all the outputs I have seen, I think in general it's quite flat and any cold shots will be fairly weak afairs as it will generally be Atlantic based. For all the talk of blocking, I just have not seen it personally and any amplification we see in the Atlantic looks transient due to our old friend the PV. 

For those looking for snow, it's a poor Outlook at the moment but I'm looking forward to tapping into some polar maritime air because with those low thicknesses and warm SSTS, we should see some quite decent convection coupled with quite strong winds so perfectly normal autuminal weather.

[nick sussex]

The GFS 12hrs run looks very similar to the ECM 00hrs pattern which probably means now that the ECM 12hrs will go in a different direction!

The GFS and UKMO look similar at T144hrs with that slow moving low over the UK so windy with  showers, the UKMO looks a bit colder than the GFS with rough 850 values of around -6 for the far north and Scotland so over higher ground a chance of some snow.

The GFS later makes hard going of getting the pieces in the right place, low pressure to the nw fills and we see some retrogression of high pressure but the main blocking is too far west.

Sometimes timing of upstream amplification can work for you or against, in this instance it comes at the wrong time hence we see the long drawn out drama with low pressure to the nw , that then means its sometime before the Euro high can retrogress allowing troughing to develop to the ne.

 I'm hoping the ECM might show a different way forward because the GFS takes far too long to develop anything interesting and then has the cheek to stick any blocking too far west.

Things would be much easier if we could clear low pressure further east and then see that increased amplification rather than the amplification happening with low pressure to the west because that just forces the Euro high ne into central Europe.

Anyway lets see what the ECM has to say later.

 

[bluearmy]

9 minutes ago, nick sussex said:

The GFS 12hrs run looks very similar to the ECM 00hrs pattern which probably means now that the ECM 12hrs will go in a different direction!

 

The parallel ECM had finally emerged - it doesn't follow the same path as the op in its latter stages as the Atlantic low deepens and heads ese to cross the south of the uk allowing the second Atlantic ridge to collapse across the N of the UK behind. a solution we have seen over the past few runs on either GFS or FIM.  Anyway, with the 12z GFS op not being too dissimilar to the 00z ECM op, I felt it was worth stating that the upgraded ECM op didn't see the same solution as the current one. 

[blizzard81]

17 minutes ago, Mucka said:

Never fear, FI is here! 

 

 

Some fab synoptics there, well spotted

[Mucka]

1 minute ago, blizzard81 said:

Some fab synoptics there, well spotted

Yeah all FI though, and not Op output as you point out, but something to raise hopes. 

GFS ensembles (central England)

After our little chilly snap a real mixed bag. Some colder runs showing up but mostly just noise.

[gottolovethisweather]

The UKMO t+144 indicated the 528DAM line (wintry precipitation maker if in existence) was as far South as almost the French coast by midday next Saturday, let's see if tonight's ECM follow suit? I'd be more interested if said evolution is still there by Monday/Tuesday, but whatever, the trend is our friend!

Edited November 12, 2016 by gottolovethisweather

[gottolovethisweather]

18 minutes ago, bluearmy said:

The parallel ECM had finally emerged - it doesn't follow the same path as the op in its latter stages as the Atlantic low deepens and heads ese to cross the south of the uk allowing the second Atlantic ridge to collapse across the N of the UK behind. a solution we have seen over the past few runs on either GFS or FIM.  Anyway, with the 12z GFS op not being too dissimilar to the 00z ECM op, I felt it was worth stating that the upgraded ECM op didn't see the same solution as the current one. 

 

Thanks bluearmy, what timeframe are we talking about here?