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phil nw.

Model Output Discussion 01/09/17

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2 minutes ago, knocker said:

Now what if the EPS indicates the low further to the east/south east with a westerly flow across Iceland cutting off ingress of cold air from the north east as the ridge nudges east bringing the UK within it's circulation? Just musing.

I'm sure you'd love that, old boy.

I still don't think the means in the extended offer much other than a watered down synoptic, I think viewing the clusters/individual ensembles makes a lot more sense to getting an overall picture. 

GFS 18z could become a hero or it could stick with it's guns and cause us all a worry.

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13 minutes ago, Daniel Smith said:

I'm sure you'd love that, old boy.

I still don't think the means in the extended offer much other than a watered down synoptic, I think viewing the clusters/individual ensembles makes a lot more sense to getting an overall picture. 

GFS 18z could become a hero or it could stick with it's guns and cause us all a worry.

Providing you can come to a sensible conclusion with all the evidence, and we haven't all got your expertise in this area, old boy. I find you can get a pretty fair idea where we are going from the 850mb streamlines means to get a fair idea where it's going and it's pretty much what I sad above but I look forward to your more detailed analysis.

Edited by knocker
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Charts tonight still showing promise ,just hoping that next weeks northerly will get upgraded as we move through this week .This weekend could very well see snow falling although most likely further north and with some elevation ,next week if we do get what charts are currently showing and we can get locked in for a few days or more ,could see more of us snow starved posters get in on the act ,Very early days but interesting times i,m sure . Ecm full of promise ,cheers all .:cold::yahoo:

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There's a cold spell on the way and some of us will get snow..how long will it last?..nobody knows but I would love to think it could keep reloading as the Ecm 12z shows..magic run,  very nice ens mean too.. enjoy it coldies until the next run comes out..don't worry about breakdowns, just enjoy this late autumn wintry bonus!.:drinks::cold-emoji:

Edited by Frosty.
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12 minutes ago, karlos1983 said:

ECM Ensemble mean rolling out.... :unsure2: nervous moments. 

Steady as she goes 

6AFE3F73-934A-4AA0-B4E7-80B9D00C1A67.thumb.png.2ba48c80c879fc5aa98a3677dce59d7f.png

But not looking quite so pronounced after 168, although I don’t find these the easiest of charts to read, so could be wrong, but looks like the high sinks.

240

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The issue I have with these mean charts, is they are the equivalent of counting 40 white cars and 60 black cars in a car park of 100. The mean would tell you that all of the cars are grey, when in fact none are. 

They have there uses, but only 1 ensemble chart,  if any,  will be right. I suppose they advise what has the greatest probability, but I'm not sold on them. As people say trust the trends, even if they wobble a bit. 

Just last weekend showed the wobbles that pop up, but the trend shown before has returned only a few days late. Certainly too much excitement for me so early on with all nighters already been pulled, but bring it on. It's why most of us are here and as I say,  the hunt for cold is almost as good as the hit. 

 

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35 minutes ago, Summer Sun said:

They are here https://weather.us/model-charts/euro/england/snow-depth-in/20171130-1800z.html

Not much for England and Wales at this stage 

I’m going to Betws-y-coed mountain biking the weekend!!! Help. Been watching the models and all the comments and it seems to me that this next cold snap/ spell  has come out of nowhere or am I missing something? Cheers guys loving this roller coaster and it’s not even winter yet ?

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1 minute ago, northwestsnow said:

Well only my opinion but i think the EC mean is excellent tonight :):cold:

So do I, it's a peach..winter is coming early this year!;)

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1 minute ago, northwestsnow said:

Well only my opinion but i think the EC mean is excellent tonight :):cold:

Not to shabby 850’s actually for a mean chart that far out!

A970CBF3-5B8B-4143-B9A7-41F85232204D.thumb.png.35ef503f62dc31c53cc21ccb92084580.png

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Great post Daniel and it will be interesting to see the clusters for the 12Z - in fact, essential to understand the mean properly.

I think there's a clue in the spreads:

EDM1-240.GIF?21-0  EEM1-240.GIF?21-0

Euro trough likely to be on most T240 clusters. Greenland High unlikely. But likely to be a split between a deep low or a strong high in the western Atlantic.

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Great model runs from the 12z suites apart from the GFS but that doesn't really bother me too much at present it is just good to see some consistancy between the models and the ECM 12z giving us all what we want to see tonight all the way to 240hr and even giving hints at extending beyond.

If we look at 192 when the ridge has already made its push north for greenland we can see the first signs of another attempt at ridging already getting set across eastern canada as circled in this shot here 

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Which then further develops on into the 216hr chart again circled 

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Then as we hit the 240hr chart the low following along behind slows as it approaches the ridge and we see the contour lines on the eastern side of this start to straighten

20171121_192250.thumb.png.ac521c3019a1b696fc7e38a30d846ac8.png

Then we see the start of another push of hieghts which look set for the eastern side of greenland and would hopefully help to keep the block in place here instead of hieghts falling more into a scandinavian block and the further push can also start to be seen from the 850 temp charts as a slight push of warmer uppers start to appear 

20171121_192515.thumb.png.292acd2521f1a6b340e996b6501bc287.png

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Now not that a scaninavian block wouldn't be nice but it also comes with downside like it getting sucked into an siberian high but in this situation i feel it would be our longer route to the colder uppers and some proper snow where as if the block was to stay east greenland based and would tap into the deeper cold upper air temps residing across siberia much quicker and pull them towards europe 

20171121_192411.thumb.png.ef55f5d5e407fe297dd832303ee5ed2d.png

Now of course this is all depending if the overall pattern is correct which as we know it is probably likely to change but with alot of models being in some agreement then it may be right that we will have to wait and see but we all need to remember a pattern doesn't always set on the first push of ridging sometimes it can take several goes to get that block to stick and set up right.

As for the GFS i am not too worried about it going zonal after all if you look back the archives it didn't really cover itself with glory in how it handled the block back in 2010 at extended range.

A good days model watching and onward to the 18z and hope the other models can keep the pattern up over the coming days and we see lots of the white stuff.

 

Edited by ScottishSnowStorm
Mispelling
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3 minutes ago, Daniel Smith said:

 

The clusters are more useful to get an idea on, as are the individual ensemble members, but not when they're grouped together into a mean.

This argument crops up every year and I can't be bothered to go through it all again because there are points for both arguments as well as some you didn't raise but I'm quite prepared to bow to your superior knowledge old boy

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Ecm has cold locked in.

Fantastic considering I threw the towel in last week.

Unbelievable outlook fingers crossed but looks good.

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Nice and friendly now please chaps,thankyou.:)

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4 minutes ago, CreweCold said:

Don't know why we can't all just get on, without the digs and quips- there's one thing that unites us all and that's that we are all weather enthusiasts...otherwise we wouldn't be here.

The day 10 mean chart isn't great IMO and that cannot be denied...so don't be shocked if the 12z GFS is closer to reality or if the 0z ECM is no where near as good. 

However, there is a positive, pressure remains relatively above average across the polar regions and that can clearly be seen. This suggests we may have further opportunities moving forward.

I would be massively shocked if GFS 12z is closer to reality!!!

For starters its not backed up the 2 best models - ukmo/ec, for seconds its an outlier (or close to it) in its own suite mid term.

So, with that in mind i find your post extremely half full, thats not a dig Crewe- im usually agreeing with pretty much all your posts. :)

Edited by northwestsnow
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Great post Daniel Smith. A good 'learning' post for people new to this hobby too

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1 minute ago, northwestsnow said:

I would be massively shocked if GFS 12z is closer to reality!!!

For starters its not backed up the 2 best models - ukmo/ec, for seconds its an outlier (or close to it) in its own suite mid term.

So, with that in mind i find your post extremely half full, thats not a dig Crewe- im usually agreeing with pretty much all your posts. :)

Personally I'm not a big fan of ensemble forecasting, never have been. I've seen the consensus suite flip overnight many times (especially the GEFS, but last year the ECM ensembles too).

It's always wise to remain cautious though, Knocker is correct in what he says about the ECM mean.

 

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1 minute ago, CreweCold said:

Personally I'm not a big fan of ensemble forecasting, never have been. I've seen the consensus suite flip overnight many times (especially the GEFS, but last year the ECM ensembles too).

It's always wise to remain cautious though, Knocker is correct in what he says about the ECM mean.

 

No worries matey- i'm really optimistic the outlook as cold for WesternEurope- we'll see.

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Stating the obvious but looking good this evening if it's cold you're looking for. The GFS is a slight worry though. Marry that up with the wording of the Met Office update and it's not a done deal yet with the Met hinting at a mixed, possible battleground UK, scenario which could go the wrong way. Some very good posts in this thread tonight I must say

Edited by LRD

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Both the mean and clusters are of use - after all, how many times have we seen the modelling hone in in on a solution which ends up a half way house between op runs. There are no ‘hard and fast rules’. 

It’s clear that the 12z eps are not quite as good as the 00z were past days 8/9. there were three fairly even clusters on that suite which spread to five after day 10.  How long any real cold sustains for remains pretty uncertain for the time being. The next couple days nwp are going to be fascinating and we could end up with cherry bite two still not quite delivering deep winter - it’s often the third bite at the cherry that we need although far too early to be writing this second phase off just yet - the ecm op is still on the upgrade !!

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Evening! Some interest for convective lovers this weekend if youre exposed to the Artic air on windward coasts, plenty of pyrotechnics along with sleet ,and hill snow . hail and probably pink lightning! That cold Artic air along with instability flowing across some relatively warm seas will give us some very interesting weather.

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1 minute ago, bluearmy said:

Both the mean and clusters are of use - after all, how many times have we seen the modelling hone in in on a solution which ends up a half way house between op runs. There are no ‘hard and fast rules’. 

It’s clear that the 12z eps are not quite as good as the 00z were past days 8/9. there were three fairly even clusters on that suite which spread to five after day 10.  How long any real cold sustains for remains pretty uncertain for the time being. The next couple days nwp are going to be fascinating and we could end up with cherry bite two still not quite delivering deep winter - it’s often the third bite at the cherry that we need although far too early to be writing this second phase off just yet - the ecm op is still on the upgrade !!

Each to their own Nick. Personally I have never found the ensemble mean particularly useful- seems to be more true in winter but that may just be my subjective, biased view. 

I find there is usually a fairly pronounced dichotomy in where we are to head (milder or colder) by the time day 10 comes around. Ensemble means (and the consensus of the ensembles) often fail to show the way ahead too clearly from my experience.

The Metoffice Mogreps seems the best tool to me, but we don't have access to them unfortunately.

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