Model Output Discussions 06z 04/11/16

[Nick L]

Models please folks, use this thread for more relaxed, bantery chat...

 

[Mucka]

37 minutes ago, Tamara said:

 

After mid December   ????

 

 

Tamara ramping?

I'm shocked I tell you, shocked! 

 

So looking at the 2m temps within the ensembles, both ECM and GFS trending colder through the mid term last 48 hours with more and more members maintaining the cold beyond/

 

 

Not a bad trend to have and one I hope ECM 12z set maintain and improve upon.

Slowly we are seeing more cold options creep in as the block is modeled less and less to sink and the longer it is maintained the more likely we we will get the favourable undercut to help it achieve better orientation and coax it further North allowing for the colder upper air to be drawn toward our chilly little rock.

If we can achieve those conditions that will allow for snowfall then the soil has had good preparation to rid itself of any latent warmth. 

[northwestsnow]

Well as you were, HP dominating our weather for the forseeable, coldies might have to show some patience, whats new?

Im fascinated by the posibility of some frost and fog as the flow come off the continenent...

[Mucka]

47 minutes ago, CreweCold said:

Except, odds wise you've probably got equal chance of hitting, say, 5 numbers in the lotto to that evolution occurring. That was a unique winter.

Indeed, but on the other hand

Something is only unique until it is repeated. 

Edited November 28, 2016 by Mucka

[Frosty.]

Tonight's Ecm 12z ensemble mean looks solidly anticyclonic next week too with sunny periods, variable cloud cover & frost and fog where skies clear. a chilly seasonal start to winter..Yay

Edited November 28, 2016 by Frosty.

[karlos1983]

59 minutes ago, CreweCold said:

Except, odds wise you've probably got equal chance of hitting, say, 5 numbers in the lotto to that evolution occurring. That was a unique winter.

To be honest, I'm not that picky, I'd take a variation of the theme 

[Catacol]

Macro features all looking good as the forecasted mid-December start to a potentially outstanding winter gets closer to the reliable. As Tamara posted earlier a -AO looks highly likely as surging heights on the Pacific side threaten a cross polar link up just when tropical convection and increased angular momentum looks to start a new phase of forcing that will not support a flat pattern. I'm not sure the timing could be any better if we dreamed it. Taking the usual tropical cycle length of approx 30+ days I would suggest that an increasingly wintry flavour to December will hang through the Xmas period and on into early January. Whether we get a really sustained period of favourable forcing through January will depend on whether we can get yet another beneficial 'spiky' phase in January and sustained  attacks on the vortex. This kind of forecasting is beyond my skill, but I'm sure GP and Tamara will keep us in the loop as December progresses.

In the shorter term, micro forecasting in our neck of the woods, I would make 2 observations. Firstly the models are poor at predicting when a high pressure cell is going to impact NW Europe, but equally once high pressure is in charge the models almost always sink it or shift it east faster than what happens in reality. The fact that the modelled pattern appears to be stagnant suggests to me that some form of retrogression is more likely than a sinker. However secondly even if the jet forces over the top and wins out it looks almost inevitable that heights will surge and return fast, and with rising AAM and a weak vortex probably to a higher latitude.

So either the high retrogresses - and we win. Or it sinks for a very short period and we win again shortly after. How often does a scenario look win/win for us?

Best winter outlook in ages. Even Dec 2010 didn't look quite as good from a longer term perspective.

Edited November 29, 2016 by Catacol

[Northern Sky]

59 minutes ago, knocker said:

Well i was sitting in a radar with no heating tracking a radiosonde and freezing my cobblers off at that time and as far as I''m concerned you can keep it.

Ah, I always wondered about the fascination with Sidney hiding his nuts and this explains it...

[nick sussex]

Looking at the ECM ensemble spreads theres likely to be a cluster of solutions that pull that Scandi shortwave further sw  closer to Denmark. This ties in with the 850 spread which suggests some colder uppers skirt with the se.

It does look like several shortwaves will work their way south on the eastern flank of the high. These could alter track depending on the amplification upstream.

Theres not much spread in the Med which means its going to be a hard slog to get any colder air much further west as theres little sign of lower heights there.

Again though this could change depending on the upstream pattern.

 

[fergieweather]

12z ECMWF ENS set against model climatology lean pretty firmly in median 2m temps towards below avg (at times quite markedly) out to at least 9 Dec. 

Edited November 28, 2016 by fergieweather

[Glacier Point]

....and a big intrusion if the N Pacific ridge into the Arctic towards the mid Atlantic ridge. Strongly negative AO latter stages of the EPS

[feb1991blizzard]

Just now, fergieweather said:

12z ECMWF ENS set against model climatology lean pretty firmly towards below avg (at times quite markedly) out to at least 9 Dec. 

And towards drier (very markedly) as well though?

[fergieweather]

We're especially interested to see what cohesion in broader signal appears 2nd half Dec in EC Monthly at 10pm, versus latest GloSea5.

[northwestsnow]

3 minutes ago, fergieweather said:

12z ECMWF ENS set against model climatology lean pretty firmly towards below avg (at times quite markedly) out to at least 9 Dec. 

Sounds fantastic Ian, can you let Exeter know, their mrfs are getting odder by the day....:D

[fergieweather]

2 minutes ago, feb1991blizzard said:

And towards drier (very markedly) as well though?

Yes, re majority signal. Happy days. :-)

[Ali1977]

5 minutes ago, fergieweather said:

Yes, re majority signal. Happy days. :-)

Commuters, Elderly etc..  will rather it be dry, rather than a 1962/3 style set up but it would still be great to get the block to the North and get some white stuff over Xmas. Imagine how cold even the next few nights would be with a covering of snow around!! 

Edited November 28, 2016 by Ali1977

[Mark wheeler]

I hope you've got your notes ready stewfox  for tmrws edition .

Tonight I have seen something I have never seen in all my time on here . A ramp from Tamara , I had to double check . The slight corrections in the right direction for cold have been both intriguing and painfull slow to watch but I'm hoping a reward for years of mush is just round the corner . Momentum is with us . 

[knocker]

11 minutes ago, Glacier Point said:

....and a big intrusion if the N Pacific ridge into the Arctic towards the mid Atlantic ridge. Strongly negative AO latter stages of the EPS

I must admit I don't quite follow that as the mean is broadly speaking neutral from around the 10th. on the updated graph that I've seen

Edited November 28, 2016 by knocker

[Ravelin]

I'll swear some people have the memory of a goldfish. 

ECM charts for below for 1st Dec. On the left the D10 chart from this time last week, on the right today's chart for the same time. Can anyone spot the difference?

  

Now anyone that's convinced that the UK high that is currently forecast to hang over us out to D10, can you please explain why (other than paranoia) that the ECM is any more correct today for D10 than it was at this point last week.

For completeness, the same charts for the GFS,

  

[marksiwnc]

Models are settling down after a hard time finding out where the high would settle.  I think it may travel a bit more ne during nxt week dragging colder air down to us.  Hopefully there will be some snow chances from the middle of nxt week onwards.  probably only grazing the SW and south maybe.  what do you think gp,fergieweather??! 

[johncam]

Hi Ian, does the below avg temps also show for us up in central Scotland?

 

thanks

[swfc]

either ive missed something or the nhp is ready to deliver some incredible output!!!!

[nick sussex]

1 minute ago, Ravelin said:

I'll swear some people have the memory of a goldfish. 

ECM charts for below for 1st Dec. On the left the D10 chart from this time last week, on the right today's chart for the same time. Can anyone spot the difference?

  

Now anyone that's convinced that the UK high that is currently forecast to hang over us out to D10, can you please explain why (other than paranoia) that the ECM is any more correct today for D10 than it was at this point last week.

For completeness, the same charts for the GFS,

  

Because its sods law! lol The upstream pattern has very good model agreement and hence things will only change slowly however within that theres still the possibility to cut some energy under the block.

I'm happy for the block to hang around as long as its warmer upper temps are cut off by low heights in the Med, for that reason we want the ECM op to be totally wrong.

At this point the high looks like a shoe in for the next 7 to 10  days but its where it exactly sets up or whether we can impart some colder uppers that could still change.

 

[feb1991blizzard]

Imagine what damage this stonking Pacific ridge combined with our one would do to the Mid to lower strat on the 0z FIM.

[bluearmy]

9 minutes ago, Ravelin said:

I'll swear some people have the memory of a goldfish. 

ECM charts for below for 1st Dec. On the left the D10 chart from this time last week, on the right today's chart for the same time. Can anyone spot the difference?

  

Now anyone that's convinced that the UK high that is currently forecast to hang over us out to D10, can you please explain why (other than paranoia) that the ECM is any more correct today for D10 than it was at this point last week.

For completeness, the same charts for the GFS,

  

But we had a bust on the eps this time last week re the upcoming upper ridge being modelled as an upper trough! to get two busts in two weeks on the eps re the 8/12 day period would indeed be fairly unprecedented.