Model Output Discussions 06z 04/11/16

[Jonan92]

In my opinion the main reason for the first block to fail is the little low north of Florida. It gets attracted by the Canadian low and in consecuence it gets much stronger

The three main models see this happening. However, it is interesting to note that Navgem didn't see that happening in the 6z run

That would change a couple of thing in short-medium range.

It's another possible scenario, althoug one with a low probability. I am sure that it will change in the 12z run, but thought it should be noted

[Ali1977]

Not sure when this came out but the CFSV2 now showing a blocked winter - a bit of a turn around.

[bluearmy]

Jonan - can't remember the last time that NAVGEM  was right in the face of the main models 

[Jonan92]

Just now, bluearmy said:

Jonan - can't remember the last time that NAVGEM  was right in the face of the main models 

I know, I am not saying it's right, just showing that there are another possibilites (small I know), those kind of lows are hard of tracking and you never really know what can happen

[Summer Sun]

The NAO and AO both look like going negative before the week is out

[Gael_Force]

9 minutes ago, Ali1977 said:

Not sure when this came out but the CFSV2 now showing a blocked winter - a bit of a turn around.

It tells you when it refers to .. initial conditions 4-13 November.

Besides, it is available as monthly rather than seasonal so less mixing out of signals.

http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/glbz700e3Mon.html

 

[Ali1977]

1 minute ago, Gael_Force said:

It tells you when it refers to .. initial conditions 4-13 November.

Besides, it is available as monthly rather than seasonal so less mixing out of signals.

http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/glbz700e3Mon.html

 

Cheers, even better with those. Dec and Feb have strong signals and Jan still has a signal for blocking. Yes it's the CFSV2, still interesting that it flipped. 

[Mucka]

Some great updates from Fergie and thoroughly good read from Tamara. We are still seeing strong background signals accompanied by modeling for higher probability of blocking end of November and through December.

I understand we coldies can be over optimistic but I really see nothing not to be excited about if you are int he cold camp.

Even now, despite mention of mild and flat patterns we are in anything but the sort IMO.

The "breakdown" of blocking and return to mobility looks very short lived as was forecast.

Look at the bigger picture. The breakdown such as it is and return to Atlantic driven weather consists of a trough grinding to a halt to our North and filling. And as far as the models can be believed, that's it!

Sure it will be unsettled under this trough, first under a chilly NW flow for a few days and then under a milder W/SW flow for a few days as the trough tilts and fills. Thereafter we should see temps around average, remaining somewhat unsettled but anything but mobile as we have a strong Atlantic ridge and high pressure to our East.

That takes out to the extremes of reliable output (say day 8 to 10) as far as broad-scale upper pattern is concerned and that time is only extended because the pattern is so slow moving.

It should slowly become more settled from there with high pressure close to or over the UK day 10+ 

This is where we ask does blocking take hold proper in the last week of November?

Quite possibly though by no means certainly but if it does then there is every chance of a cold outbreak beginning before November is out. 

I will admit I personally look for cold solutions even where there are non showing in the output but I will outline my thinking on what could possibly develop, more often not that is modeled at some stage even if it does not come to fruition so they are pretty sound for the most part. However sometimes there is no need to look for convoluted mechanisms to bring about some amplification or blocking that could lead to cold as it is consistently being modeled and currently we are seeing blocking consistently being modeled.

Yes that is in FI and I get it, many times we see blocking modeled in FI disappear in the more reliable time-frames but the pattern we are seeing unfold is broadly reliable, that is blocking to our NW and E as we head off into the jungle of FI.

No way to know how that will develop or whether blocking will position and orientate itself to suit our cold dreams and whims but as far as buying tickets to the Winter lottery is concerned I would say we have been buying frantically throughout the autumn and have a trolley full.

Now it's just a case of eyes down and see.

 

EDIT

Looks like close but no cigar on the 12z but if I were looking for an example of a likely retrograde pattern then this wouldn't be far off. 

Edited November 14, 2016 by Mucka

[knocker]

The GFS this evening is not without interest from the end of the week.

The upper trough that has tracked in from the NW stalls over the UK as the European HP amplifies and surges NE. But events are afoot as energy continues to shoot out of Canada to supplement our trough which is also subject to a another attack from the SE courtesy of energy emanating from the southern states

As this phasing in of the upper troughs gets to work the trough over the UK is quite active and swings on it's axis and with amplification now well under way we have a very meridional pattern by Sunday leaving to a large low pressure area covering the eastern Atlantic, including the UK. bringing quite unpleasant windy conditions with showers which could well bewintry with snow on the high ground in the north

From then on the main emphasis is on the Atlantic HP as it pushes the trough south ending withe proverbial cutoff upper low to the west of Iberia and a very nice Omega block. (almost two). All of this of course centres the surface low pressure to the south west and introduces some very nice WAA to England and temps above average.

Edited November 14, 2016 by knocker

[jvenge]

Welcome back, Knocker. I missed your morning summary posts of the GFS.

[I remember Atlantic 252]

12Z on netweather still not got past +123?

[Banbury]

Control goes the way we'd want it right at the death

[North East Blizzard]

The mean is pretty impressive too. I know its way out in fi, but quite a lot of the ensemble's have some form of high up to Greenland. Far to early to get excited, but with the background signals and such, its a possibility

[Mucka]

GFS 12z ensembles (Central England)

A slow decline in temps through the last week of November and just the hint of a cold signal at the death. Let's hope for that signal to sharpen up and get brought forward.

[feb1991blizzard]

Just now, North East Blizzard said:

The mean is pretty impressive too. I know its way out in fi, but quite a lot of the ensemble's have some form of high up to Greenland. Far to early to get excited, but with the background signals and such, its a possibility

Strange that the ECM ensembles are becoming milder late on, we really need to see a good cold cluster appearing on the next few runs to start having confidence in the admittedly strong and consistent GEFS signal for a Greenland height rise.

[nick sussex]

Looks like the ECM has been leading the way with the pattern and especially the development of that initial low pressure. The GFS and UKMO have been behind the curve, lets hope the ECM can deliver something better which the others can then follow.

The Russian high is a total pain here, poorly orientated and just stopping eastwards movement in the pattern. Nothing can come of that Russian high and any interest needs to develop by way of high pressure to the nw/n.

 

[Scandinavian High.]

This looks interesting back end of November hope this winter coming we get the prize some hard frosts and snow very interesting winter a head.

[Ali1977]

A pretty good FI mean, if this was to verify we would be entering Dec in a cold, if not very cold pattern. Get this into the medium range and keep these signals going and this "may" be a decent prolonged blocked/cold spell , with the chance of it being something quite special. A few hurdles yet though.

I wouldn't be surprised if some better chart materialised towards day 10, the formation of the block is quite complex although now looking more likely. As these block decide where they're heading weather patterns can change very quickly.

Some 2 day jumps on the control to prove my point, big changes for us in small time franes

Edited November 14, 2016 by Ali1977

[feb1991blizzard]

18 minutes ago, nick sussex said:

Looks like the ECM has been leading the way with the pattern and especially the development of that initial low pressure. The GFS and UKMO have been behind the curve, lets hope the ECM can deliver something better which the others can then follow.

The Russian high is a total pain here, poorly orientated and just stopping eastwards movement in the pattern. Nothing can come of that Russian high and any interest needs to develop by way of high pressure to the nw/n.

 

Nothing in the medium range but it can be a precursor to an SSW, not that we really need a significant (technical) SSW anyway.

[bluearmy]

The second atlantic system is very progressive on the 12z ecm (in speed rather than development)

[Nick L]

The EC really ramps up this storm for Sunday, 80-90mph gusts through the channel! Interestingly would dump a hell of a lot of snow over the Welsh mountains.

[feb1991blizzard]

2 minutes ago, Nick L said:

The EC really ramps up this storm for Sunday, 80-90mph gusts through the channel! Interestingly would dump a hell of a lot of snow over the Welsh mountains.

Pity it cant correct 500 or more miles further south.

[Grimers]

3 minutes ago, Nick L said:

The EC really ramps up this storm for Sunday, 80-90mph gusts through the channel! Interestingly would dump a hell of a lot of snow over the Welsh mountains.

Is this using a detailed model that's available to the public?

[nick sussex]

3 minutes ago, Nick L said:

The EC really ramps up this storm for Sunday, 80-90mph gusts through the channel! Interestingly would dump a hell of a lot of snow over the Welsh mountains.

Oh dear, I wanted it do something different but not that. Snow fine but not those winds.

[Nick L]

2 minutes ago, Grimers said:

Is this using a detailed model that's available to the public?

Yes, I have access to the 3 hourly data through work.