Model Output Discussion 29th December - Into mid-Winter.

[Frank Trough]

What have we learned from recent experience? As soon as a model starts eroding a cold spell it just seems to gather pace. 

We'll see tonight but my guess is the ecm won't be as good. Just seems to be our luck.

[SMU]

Its worth reining in all the ney sayers above

Remember the forecast for model change I put out on the 1st / 2nd - for the 10th Jan

This was the GFS 168

now this is the actual expected - inline with the euros

tota chalk & cheese with amplication...

 

[bobbydog]

2 minutes ago, ArHu3 said:

why would it be worse than the 0z or 12z?

Because it's been proven beyond doubt by anecdotal rumour, myth and legend...

[snowice]

4 minutes ago, northwestsnow said:

Bloody gfs!!!

Is anything straighforward in this country!!!!!!!

6z cuts the cold off by saturday, its much worse than the 0z run 

...

One good thing in our favour is how Gfs flip flops between runs

[northwestsnow]

1 minute ago, Steve Murr said:

Its worth reining in all the ney sayers above

Remember the forecast for model change I put out on the 1st / 2nd - for the 10th Jan

This was the GFS 168

now this is the actual expected - inline with the euros

tota chalk & cheese with amplication...

 

Just frustration on my part steve.

Im sure your right, looking forward to meto update.

[Day 10]

3 minutes ago, Gustywind said:

To be honest I don't know why peeps bother paying much attention to either the 6 or 18z runs with the GFS, they are little better than the likes of NOGAPS from what I've seen. 

Less we forget it was the 6z that produced 'that run' a couple of weeks back, so why anyone thinks it's more likely to be right now I don't know.

 

Yes was just going to post similar. I thought the 6Z gfs was renowned for being the most unreliable run of the day. At least it's the gfs showing the worst outcome and not the UKMO like last time. That fills me with more hope this time. As usual in cold setups pointless getting hung up on what happens post 120 anyway. Let's enjoy any snow that comes before that first I say.

[SMU]

13 minutes ago, northwestsnow said:

Just frustration on my part steve.

Im sure your right, looking forward to meto update.

At this is stage I would say the probabilities are finely balanced @ around 50/50 UKMO V ECM

Edited January 8, 2017 by Steve Murr

[Frosty.]

This is a good test for the new improved Ecm compared to the much maligned Gfs..Fingers crossed we see a good cold outbreak.

[Methuselah]

2 minutes ago, Day 10 said:

Yes was just going to post similar. I thought the 6Z gfs was renowned for being the most unreliable run of the day. At least it's the gfs showing the worst outcome and not the UKMO like last time. That fills me with more hope this time. As usual in cold setups pointless getting hung up on what happens post 120 anyway. Let's enjoy any snow that comes before that first I say.

Are there not verification stats available that either prove or disprove that hypothesis?

[TEITS]

11 minutes ago, Gustywind said:

To be honest I don't know why peeps bother paying much attention to either the 6 or 18z runs with the GFS, they are little better than the likes of NOGAPS from what I've seen. 

Less we forget it was the 6z that produced 'that run' a couple of weeks back, so why anyone thinks it's more likely to be right now I don't know.

 

Interesting you say that because the only model that I can see that supports a short cold snap like the 06Z is the NAVGEM.

[IDO]

10 minutes ago, Gustywind said:

Not sure, although I've seen posts in the past that say they have less data than the other 2 runs.

As I say it's just my perception from 12 years of model watching, they seem to come out with more volatile and extreme outputs than the 0 or 12 runs, be that cold, storms or heat. 

Funny enough D10 GFS 18z and 06z have better verification over the last month with heights and bias, so I would not discount them:

[Day 10]

5 minutes ago, Ed Stone said:

Are there not verification stats available that either prove or disprove that hypothesis?

I don't have any, but yes would be interesting to see the inter run gfs verification stats to see if that theory on here stacks up?

[mountain shadow]

35 minutes ago, January Snowstorm said:

I mentioned last night I saw nothing more than a 24 hour toppler. The 06z is firmly in that camp this morning.

Snow showers on Thursday/night

So you are saying that the 6z GFS will verify better than the ECM and UKMO 0z runs?

 

[Singularity]

GFS 06z adjusts the mid-Atlantic low S which could have been good but it still has the progressive N American solution so it just leads to an even flatter outcome across the Atlantic.

Unusual to see quite this much divergence between models in terms of jet strength and configuration from as early as +96 hours. What gives? 

[January Snowstorm]

11 minutes ago, snowice said:

One good thing in our favour is how Gfs flip flops between runs

I don't see that it has. The last 3 gfs runs all showed the atlantic gaining ground after the Thursday/night snow window. All has happened as it has dropped the idea of snow coming from the atlantic low on Saturday.

Folks we have learned well before this Winter that if something can go wrong it will when it comes to achieving cold

[January Snowstorm]

Just now, mountain shadow said:

So you are saying that the 6z GFS will verify better than the ECM and UKMO 0z runs?

 

In the reliable timeframe yes.

The ECM ' S interest remains in FI and the Meto have already stated an Easterly is a minority chance!

[Ali1977]

3 minutes ago, January Snowstorm said:

In the reliable timeframe yes.

The ECM ' S interest remains in FI and the Meto have already stated an Easterly is a minority chance!

The GFS op has plenty of support from the ENS, I really hope this changes next run. 

[samadamsuk]

Morning all,

 

Looks finely balanced to me - the fly in the ointment from what I can tell is the cyclogenesis around the tip of Greenland at 120h +,, which either ramps up allowing WAA to invade and HP to move back in, or as with the ECM if it doesn't develop and so holding the WAA back west and it's game on for the UK. The GFS ensembles seem split after T120, with the Op and the control being mild outliers (from what I can tell)) - always a difficult one though as the ens run at lower resolution as we know so not always the best guide.

Fingers crossed! I'm not actually a coldie, but I love extremes, so hell bring it on - I turned 40 last year, but I'll be straight out to get a sledge if it looks nailed on!

 

Samos

 

[ArHu3]

3 minutes ago, Ali1977 said:

The GFS op has plenty of support from the ENS, I really hope this changes next run. 

ecmwf is also very sure of itself, check this plume for De Bilt of the 0z

http://www.weerplaza.nl/15daagseverwachting/?type=eps_pluim

[nick sussex]

It would be great if a cold spell could come without some drama but this seems to be the way of things so we're left now with the GFS 00hrs which wasn't upto much and then the following 06hrs run even worse so in terms of the GFS this is going the wrong way and does dent confidence. A backtrack towards the ECM on the GFS 06hrs run would have left us with more optimism when facing tonights outputs.

I've trawled every NCEP state forecast which would be effected by the differences and to add to the frustration they've not come down on either the ECM or GFS. Perhaps we might get an update before tonights drama kicks off.

The difference is really to do with the speed of shortwave energy running east across the USA and whether this phases and makes one system over the ne Canada or whether we see no phasing which then leaves that shortwave over southern Greenland.

If you're going on the past week and the GFS performance upstream then you'd back against it however just because it failed then doesn't mean its wrong now. I'll endeavour to keep searching for more upstream info to discredit the GFS!

Edited January 8, 2017 by nick sussex

[IDO]

7 minutes ago, ArHu3 said:

ecmwf is also very sure of itself, check this plume for De Bilt of the 0z

http://www.weerplaza.nl/15daagseverwachting/?type=eps_pluim

Assuming the op and control are similar after D10 then they are massive outliers. Look at the dew point for the region; the mean is positive in FI but the Control is 16c lower the last few days! That is well outside the parameters of standard deviation and IMO outlandish outliers.

The temps not so much, but still coldest solution, but a continental flow or faux cold could keep many of the members colder. Very few going with easterly either:

I cannot take the ECM 0z seriously. 

Edited January 8, 2017 by IDO

[SMU]

13 minutes ago, IDO said:

Assuming the op and control are similar after D10 then they are massive outliers. Look at the dew point for the region; the mean is positive in FI but the Control is 16c lower the last few days! That is well outside the parameters of standard deviation and IMO outlandish outliers.

The temps not so much, but still coldest solution, but a continental flow or faux cold could keep many of the members colder. Very few going with easterly either:

I cannot take the ECM 0z seriously. 

The mean dewpoint doesnt go positive mate as you infer.

[blizzard81]

1 hour ago, Daniel Smith said:

The low stops high pressure in the Atlantic from building North-Eastwards and we'd likely see a return to milder Westerlies similar to the GFS. 

The ECM doesn't develop that low so the high builds Norh-East and we end with an Easterly. 

How come these little lows seem to crop up out of nowhere? Plus they always scupper any chances of prolonged cold. 

[SLEETY]

6 minutes ago, IDO said:

Assuming the op and control are similar after D10 then they are massive outliers. Look at the dew point for the region; the mean is positive in FI but the Control is 16c lower the last few days! That is well outside the parameters of standard deviation and IMO outlandish outliers.

The temps not so much, but still coldest solution, but a continental flow or faux cold could keep many of the members colder. Very few going with easterly either:

I cannot take the ECM 0z seriously. 

If it was showing mild would you be taking it seriously then☺they could be trendsetters ,it's hard to know at that timescale ,more runs needed as ever.

[Methuselah]

11 minutes ago, IDO said:

Assuming the op and control are similar after D10 then they are massive outliers. Look at the dew point for the region; the mean is positive in FI but the Control is 16c lower the last few days! That is well outside the parameters of standard deviation and IMO outlandish outliers.

The temps not so much, but still coldest solution, but a continental flow or faux cold could keep many of the members colder. Very few going with easterly either:

I cannot take the ECM 0z seriously. 

Looking at that spread, I wouldn't give the op, control much credence at all - whatever they happen to show...