Model Output Discussions 12z 01/09/2016

[Thermohaline Conveyor]

4 minutes ago, Frosty. said:

I understand GloSea5 is indicating increasingly blocked conditions later in Nov and wouldn't it be amazing if we had another 2010 Nov / Dec freeze!

White Christmas anyone?  Now wouldn't that be lovely! The extent of the Eurasian snowfields is certainly encouraging.

[weirpig]

2 minutes ago, feb1991blizzard said:

Theres an EC46 tonight, over to the usual suspects if they can be kind enough to do us the honours around 11pm tonight>

Yep and I believe it is the seasonal tomorrow ??

[feb1991blizzard]

Just now, weirpig said:

Yep and I believe it is the seasonal tomorrow ??

Seasonal ECM or GLOSEA5 public charts on the UKMO site?

[weirpig]

Just now, feb1991blizzard said:

Seasonal ECM or GLOSEA5 public charts on the UKMO site?

I'm sure it's the ecm seasonal I believe it's usually on the 4th 

[Frosty.]

The GEFS 12z mean looks interesting for coldies during the second half of November with indications of further Arctic outbreaks.

[fergieweather]

18 minutes ago, weirpig said:

I'm sure it's the ecm seasonal I believe it's usually on the 4th 

No, 8th (Tues). 

[Summer Sun]

JMA doesn't quite manage to bring in the -8 850's tonight unlike 24hrs ago

[Methuselah]

5 minutes ago, fergieweather said:

No, 8th (Tues). 

Thank you, Ian...I even got in before you'd attracted 200 'likes'!

[jules216]

Ecmwf updated on 1st covering November and December,see link below, looks good to me re. blocking,temps good Nov. A bit meh for Dec

 

http://forest.jrc.ec.europa.eu/effis/applications/long-term-forecast/seasonal-forecast/

[ANYWEATHER]

Good Evening Folks! Quite simply the Ecm shows a blocked pattern the gfs an unblocked pattern! Ecm = cold     Gfs =mild 

[Summer Sun]

Any chance we could maybe have a new thread ahead of the weekend and the impending cold snap / spell?

After 2 months this is rather long now

[Man With Beard]

3 hours ago, fergieweather said:

... in such a period of clear model volatility, with a bit of a knife-edge between the westerly/mobile solutions versus the more blocky ones, it's not sufficient to simply rely on ENS means. They will be skewed (in any model - not just GFS) by the more 'energetic' members (=the westerly ones) and may not offer reliable route ahead *if used or cited in isolation*.

Oh thank you Ian - thank you! This is just so true. Can I quote you on this for .. the next ten winters?? (Feel free to quote me as well of course, I am top of the CET challenge after all, isn't that almost as good as being chief forecaster at the Met??)  

Better get back on topic quickly ...

It must be mentioned that the GEFS is very confident that it has got Scandi right at T168

I have a problem here, because I have two sayings - one is "Never ignore the GFS" and the other is "When the ECM and UKMO agree at T144, they will be right". So I'll see if the NOAA can help me out - no chance (edit - JH / Knocker that's because it isn't decisive enough one way or the other for me, not because I think it's useless!!!)

a teeny bit of heights to the NE, but will they be too far away from us to influence us? NOAA probably says yes.

I sense a classic wintery knife-edge situation coming up - possibly even a T24 job on where exactly the Atlantic front will meet the Europe trough, which is the all-important question.

But wow, who thought we'd be here so early in the season. (went to type winter and realised it's still 27 days away!!)

Edited November 3, 2016 by Man With Beard

[bluearmy]

The ECM spreads at day 7 show the situation well.  All the uncertainty on how far west the trough is backed up. 

[Frosty.]

To my untrained eyes the Ecm 12z ens mean isn't looking as progressive as earlier, certainly not as far as the Azores ridge is concerned which looks more suppressed..I think it's backtracking towards what the 12z op shows..which is very good news in terms of extending the cold!..baby steps in the right direction and hopefully the 00z will continue the backtrack!

Edited November 3, 2016 by Frosty.

[swfc]

been a busy day on here today and a lot of people seem to have got a head of themselves post 5-6 days?.the last 24-36 hours have shown a rise in pressure towards scan and the north east.this was called correctly by sm .the pv is wanting to sit over greenland and push or try to push se.given the state of flux the nh is showing id sit tight for 48 hours before getting to carried away with mid - late november expectations

Edited November 3, 2016 by swfc

[fergieweather]

2 hours ago, northwestsnow said:

Old skool November on the cards, and i love it !! (Doesn't mean snow, but it means cold foggy and frosty )..

 

Hmmmm.... don't discount it! Snow showers possible down to circa 300m on Monday (in eastern areas) and dropping further down to 200m on Tuesday (probably focused in the SE corner of England), based on latest UKMO-GM, as the flow drops-away and picks-up an ever more maritime fetch, and the convective depth starts to increase . Never say never...

[Ali1977]

Does this mean anything to anyone? 

Is that a new mean chart? Showing a Greeny high or an old one?

Edited November 3, 2016 by Ali1977

[bradymk]

4 minutes ago, Ali1977 said:

Does this mean anything to anyone? 

Looks like the difference in Height anomalies for the 12z ECM ENS compared to the 00z ENS run. So basically ECM 12z ENS showing large difference in height anomalies particularly in mid Atlantic and to our north east compared to 00z in the mid range.

I guess with the weeklies, he means to sort of disregard the weeklies tonight because his following tweet says these are initialised using 00z ECM data and due to the big change in the ENS tonight, they may be more inaccurate.

Hope that helps 

[Mark Neal.]

13 minutes ago, Ali1977 said:

Does this mean anything to anyone? 

Is that a new mean chart? Showing a Greeny high or an old one?

Thats an ensemble mean made of 51 members from the 12z ECM ENS. Looks like the difference since the last run, hence the highr heights towards Greenland and also beyond Russia. Lower height anomaly & lower pressure in between (including blighty) would likely be a colder scenario. 

Edited November 3, 2016 by Mark N

[feb1991blizzard]

17 minutes ago, Ali1977 said:

Does this mean anything to anyone? 

Is that a new mean chart? Showing a Greeny high or an old one?

He is saying you can throw out tonights EC32 based on the fact that its based on old data (same starting data used in ECM run a day ago which was more progressive with atlantic) and the new data (the data that threw out some dreamy synoptics) would have produced vastly differing (and colder)  results

Edited November 3, 2016 by feb1991blizzard

[Frosty.]

9 minutes ago, feb1991blizzard said:

He is saying you can through out tonights EC32 based on the fact that its based on old data (same starting data used in ECM run a day ago which was more progressive with atlantic) and the new data (the data that threw out some dreamy synoptics) would have produced vastly differing (and colder)  results

Yes it's something I alluded to above regarding the change in the Ecm 12z ensemble mean compared to the 00z earlier, hope it keeps changing for the better / colder!

Edited November 3, 2016 by Frosty.

[Mark Neal.]

With a colder spell on the horizon. Almost time to dig out the Euro 4 and look at anything snow signal wise. As you can see potential on Saturday as colder air floods into Scotland from a northern source. Chance of sleet/snow and especially over the higher ground.. 

 

[Tamara]

11 minutes ago, fergieweather said:

Hmmmm.... don't discount it! Snow showers possible down to circa 300m on Monday (in eastern areas) and dropping further down to 200m on Tuesday (probably focused in the SE corner of England), based on latest UKMO-GM, as the flow drops-away and picks-up an ever more maritime fetch, and the convective depth starts to increase . Never say never...

I'm 70m adrift of that present calculation

But if I have some faith in my own forward thinking that bodes well for more than a 70 metre drop in rinse and repeat scenarios in the coming weeks

Never say never indeed...

 

 

 

 

[Glacier Point]

6 minutes ago, Mark N said:

Thats an ensemble mean made of 51 members from the 12z ECM ENS. Looks like the difference since the last run, hence the highr heights towards Greenland and also beyond Russia. Colder and lower heights in between (including blighty

It's the difference in 500hPa heights between 00z and 12z runs. FWIW the 12z was 140m lower with its heights to the west of the UK mid next week during that critical phase so support for the op. The EPS also broadly supports the spirit of the op to return to a mid Atlantic ridge scenario in the extended range, and trough returning to Scandinavia.  I suspect our sojourn with pv over Greenland will be a brief one.

[Mark Neal.]

Side note, obviously smaller range models will likely pick up on features in the flow such as the scenario which *could* occur as Ian Fergusson said. Also worth noting ( i know Pete has mentioned) but SSTs in north sea are very high currently and with colder air likely to come our way, could be very convective and pep up showery activity, something to watch, certainly.