Model Output Discussion 01/09/17

[LRD]

Just now, CreweCold said:

Again, it means little.

The BBC/Metoffice were fully confident of colder weather with snow for early December last year. They were saying this mid November. There was a screenshot on here for the look ahead summary on their extended forecast but it seems to have been taken down from the thread....

I completely disagree that the opinions of professionals means little. 

In danger of going off-topic but the met office website updates never saw cold last year. Admittedly mid/late November 2016 there were some rumblings that the mid term was going to see something of interest but those website updates never did see it

[ANYWEATHER]

4 minutes ago, CreweCold said:

Again, it means little.

The BBC/Metoffice were fully confident of colder weather with snow for early December last year. They were saying this mid November. There was a screenshot on here for the look ahead summary on their extended forecast but it seems to have been taken down from the thread....

Edit found it..

 

[Cheshire Freeze]

Just now, SN0WM4N said:

I can't quite see the problem. They made a forecast one that was well rounded and had the highest PROBABILITY, it was wrong but that's why it's a forecast. We don't have crystal balls and magic rituals to predict the weather accurately all we have is computer models which solve large equations to predict the weather.

They among with many made a forecast that didn't come to fruition. Which is why it's a forecast not a statement.

 

The point is that sometimes we have the resources to make our own decisions over probabilities. 

I believe that @Steve Murr was one of the first to spot game over last year as he was monitoring the zonal winds. This was well before the likes of the Metoffice even seemed to twig on that it wasn't going to plan.

This is not to bash any forecasting agency, I'm just making a point

[Polar Maritime]

Just model output discussion please.

[northwestsnow]

Nice chart from ecm at 120-

Snow showers across parts of Scotland- and mainly dry and cold elsewhere. Not bad for mid November 

[mulzy]

5 minutes ago, northwestsnow said:

Nice chart from ecm at 120-

Snow showers across parts of Scotland- and mainly dry and cold elsewhere. Not bad for mid November 

Indeed.

We have to be realistic and set expectations accordingly.  It's way too early for sustained wintry weather.  It's all about building blocks and the dreaded 'p' word.

Let's review in one month's time!

Edited November 7, 2017 by mulzy

[knocker]

The EPS 10-15 anomaly this evening is continuing with the previous theme

Stronger N. pacific ridge into the Siberian side of the Arctic with a more stretched Canadian vortex that has retrogressed to Alaska. This facilitates positive anomalies and pronounced ridging into Greenland and with the trough to the east of the UK digging south promotes a north westerly flow over the UK. This could well portend surface low pressure to the east by the end of the period with air tending to Arctic maritime and thus some quite wintry weather.

[mpkio2]

Hello all.

I mentioned only the other day that caution must be upheld (As other posters such as @Tamara and @CreweCold have advised too,) when looking at some of these tasty looking FL charts.

I mentioned in my last post that FLi was considered anywhere past 11/11 (t96) seeing how all models were (And still are!) in agreement up to that point-

12z GFS 07/11 t96:

12z ECM 07/11 t96:

12z UKMO 07/11 t96:

However, looking further and analyzing the recent 12z runs, I think we can further anything considered FL anywhere past t120, perhaps t144 actually, seeing how all models are in agreement with a "theme", with many similarities between them.....

12z GFS 07/11 t144:

12z ECM 07/11 t144:

12z UKMO 07/11 t144:

What we have in all models at this time is the following (In varying degrees of "theme"): Main lob of PV in North Canada/Greenland, Arctic high just north of Russia, Lows sitting over East Russia, Low sitting over Scandy, extending down to Europe and giving UK W/NW/N flow. They're all not exactly the same - but all have the same "theme" - when it gets closer to reliable, then the models will pin-point down the finer details, and we'll see which one had it right (Or all could easily be wrong! ) Perhaps this is where we're heading now?  Which isn't too bad when you look at it from a Hemespheticpoint of view (Potential for cold that is! - that Arctic high looks very TASTY! )

The accompanies ENS and Op runs could all have this wrong though! So, expect more wobbles and ups and downs while the models try to predict what the outcome could possibly be - they have a lot to work with, what with that Arctic high causing havoc up there and all. A lot of different outcomes to come, and most what have it down, maybe not until sometime next week. So enjoy the eye candy charts and enjoy the ride!

~mpkio2~

P.s.Tamara put it a lot more elegantly and technical than I ever could (I still get confused at how she explains things and sometimes I don't understand at all...but all the fascinating either way! ), but its all about all the proper drivers playing for us and hopefully hitting the jackpot. If not, well there's still chances during the winter, if the drivers play ball, that is.

[knocker]

Further to my post above the GEFS is very much in the same ball park but, and it's a big but, NOAA isn't. This could be down to the different time frame and the transitional period but that is just my supposition

[I remember Atlantic 252]

27 minutes ago, northwestsnow said:

Nice chart from ecm at 120-

Snow showers across parts of Scotland- and mainly dry and cold elsewhere. Not bad for mid November 

Not sure about dry elsewhere, that chart screams heavy rain for the NW Midlands, need the winds more northerly, for dry elsewhere to create wishbone effect

[coldwinter]

10 minutes ago, knocker said:

Further to my post above the GEFS is very much in the same ball park but, and it's a big but, NOAA isn't. This could be down to the different time frame and the transitional period but that is just my supposition

The NOAA ones looks similar to me? Or am I going blind

[bluearmy]

9 minutes ago, knocker said:

Further to my post above the GEFS is very much in the same ball park but, and it's a big but, NOAA isn't. This could be down to the different time frame and the transitional period but that is just my supposition

I don't see that NOAA chart as unreasonable knocker - the eps/GEFS  are drifting ever more troughy over nw Europe as week 2 progresses. 

[knocker]

7 minutes ago, bluearmy said:

I don't see that NOAA chart as unreasonable knocker - the eps/GEFS  are drifting ever more troughy over nw Europe as week 2 progresses. 

NOAA isn't showing the same degree of positive anomalies and ridging vis Greenland and the western Atlantic thus a flatter and weaker westerly upper flow. That, in my opinion of course, is the difference.

Edited November 7, 2017 by knocker

[Paul]

For those who like to follow seasonal models, there's some ECM and Meto data out in the open through this page:

http://climate.copernicus.eu/s/charts/c3s_seasonal/

[feb1991blizzard]

This looks like a stonker but its next update is due in 3 days time I think.

[bluearmy]

10 minutes ago, knocker said:

NOAA isn't showing the same degree of positive anomalies and ridging vis Greenland and the western Atlantic thus a flatter and weaker westerly upper flow. That, in my opinion of course, is the difference.

I thought that may be where you are coming from. I suspect the issue is that days 8 through 11 have no upper ridging on the eps whereas it really gets going thereafter. The mean 8/14 dayer is going to look fairly flat as a consequence. once we get to Friday, that chart will look a lot different. 

[Interitus]

8 minutes ago, feb1991blizzard said:

This looks like a stonker but its next update is due in 3 days time I think.

Caution required - the 500mb geopotential height reflects the anomalous warmth of the Arctic, as can be seen in the 850mb temperature charts, there are only modest positive sea level pressure anomalies to the north at best.

[Allseasons-Si]

@nick sussex,glad to see you posting again  mate,but something is troubling me....oh! i know what it is.....no shortwave commentary from you this year

so what do or did we have today in the models (and i am going to focus on that low off the south of Newfoundland)

from the gfs today at 240 hrs+ and all speculative at the moment

00z,has this break off from the main low over that area to allow heights to build in behind it but there was a shortwave behind it so not a clean cut but ends ok

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=0&ech=204&heure=0&jour=7&mois=11&annee=2017&archive=1&carte=1

06z,there wasn't a clean break away from the parent low in that area so stalled the progression of heights building into the atlantic forcing a west based -NAO

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=0&ech=204&heure=6&jour=7&mois=11&annee=2017&archive=1&carte=1

12Z,now this was the best run out of the three in terns of a clean cut FL with no shortwave drama and sharp WAA into the west side of Greenland of which this is what we want to see in future runs but it's not that simple is it

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=0&ech=204&carte=1

both the 06z and 12z control runs was spectacular in that respect.

now onto some anomoly's of which i always find usefull when looking at the bigger picture to determine where we might go

i posted the the mean chart from the gefs at 384 hrs last night of which was a good chart at that distance,now to compare with tonight one 24 hrs later

yesterday's and today's,that is still a good mean if not better than yesterday's with more heights in the Atlantic

and the gef's mean geopotential heghts is not too shabby either with the trough sinking SE into the continent

from 240 hrs it matches the latest from NOAA

http://www.meteociel.fr/modeles/gefs_cartes.php?code=21&ech=192&carte=1&mode=5

and the latest from the telleconnections

NAO gfs outlooks and ens mean outlooks,and the AO gfs outlooks and ens mean outlooks still trending negative although not as sharp on the -values as last night

 

phew!!! i need a break after all that and it's only the beginning of November lol

 

Edited November 7, 2017 by Allseasons-si

[feb1991blizzard]

2 minutes ago, Interitus said:

Caution required - the 500mb geopotential height reflects the anomalous warmth of the Arctic, as can be seen in the 850mb temperature charts, there are only modest positive sea level pressure anomalies to the north at best.

Is that why there's hardly any blue anywhere? so really its on average what you would expect climatologically from a whole uk winter averaged out over 3 months then?

[damianslaw]

Not much to add - lots of very good posts today, best day for a long time in this thread..

Models are in very firm agreement up to the medium range i.e. Sunday-Monday, not often you can say that. Trough aligned NW-SE, azores high displaced further to the west than usual, allowing another chilly northerly feed this weekend - its certainly a repeating pattern, Sunday promises to bring the third cold frosty dry sunny one in a row..

Into next week, GFS and ECM show the PV stretched and ragged over N Canada, and height development over the N Pole into N Russia - feedback mechanism eventually could lead to something much colder from the north, but temporarily we could see a weak westerly milder flow develop with the azores high ridging back NE, the trigger feature to a colder scenario being a deepening of the trough swinging down through the UK.

I'm reminded of Nov 96 at the moment, that started off quite similar to this month, we then saw a significant low pressure / trough swing down on the 18th, thereafter the month turned cold and quite snowy with winds in the east. It was a precursor to a cold mostly dry December, with some snow later on. Early winter 96/97 has come up in many analogues, it was a La Nina winter descending into solar minimum.

[knocker]

51 minutes ago, bluearmy said:

I thought that may be where you are coming from. I suspect the issue is that days 8 through 11 have no upper ridging on the eps whereas it really gets going thereafter. The mean 8/14 dayer is going to look fairly flat as a consequence. once we get to Friday, that chart will look a lot different. 

That indeed is my thinking which is why I added this to the original post. " This could be down to the different time frame and the transitional period but that is just my supposition" Of  course, as you obviously realize, this is a long way from a done deal depending as it does on the precise intensity and orientation of the amplification. But all interesting.

Edited November 7, 2017 by knocker

[MP-R]

10 minutes ago, damianslaw said:

 

I'm reminded of Nov 96 at the moment, that started off quite similar to this month, we then saw a significant low pressure / trough swing down on the 18th, thereafter the month turned cold and quite snowy with winds in the east. It was a precursor to a cold mostly dry December, with some snow later on. Early winter 96/97 has come up in many analogues, it was a La Nina winter descending into solar minimum.

Was 96-97 not a neutral winter between the 95-96 La Nina and 97-98 El Nino? It's interesting to see the similarities play in the models however. January was really quite frigid in the first half. Just not February 1997 please!

[johnholmes]

1 hour ago, coldwinter said:

The NOAA ones looks similar to me? Or am I going blind

The NOAA chart is a flatter flow from west of  n America across the Atlantic into the trough over Europe to my eyes

[Allseasons-Si]

just to edit my post above with regards the low off Newfoundland,i was meant to say east of that area not south

breaking my neck to look at it right

looking at the latest from the 18z gfs,not much of a low coming from that area,would this be a good thing or do we have that missing data debate again?

Edited November 7, 2017 by Allseasons-si

[Jonan92]

What a strange looking NH profile for November