Model output discussion - 5th December 2016 - Into Winter we go

[Blessed Weather]

30 minutes ago, Summer Sun said:

 

It appears both EC and GEFS are showing a bimodal distribution of members for early January, split as Matt tweeted. I have roughly counted 13 out of 20 GEFS members favouring heights over/towards Greenland on 2nd Jan.

Stamps   http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=240

So probably unsurprisingly, the GEFS spread for that date shows the uncertainty to our NW and in the Greenland area.

Edited December 23, 2016 by Blessed Weather
Expanded on spread area - Greenland

[frosty ground]

3 hours ago, knocker said:

Some perspective

Perspective for what?

Are you comparing a 5 day average to charts that start part way through this period, slight confused.

[karlos1983]

Not a bad 240 ensemble mean from the ecm. Nice height anomaly too. 

[Kentish Snowman in Yorks]

29 minutes ago, Summer Sun said:

 

So it's 4/5 for a cold Northerly or 5/4 for an unsettled Northwesterly?

Let's hope the favourite isn't pipped on the post!

[bluearmy]

11 minutes ago, knocker said:

One musn't forget the other player in this and that's the Russian lobe of the vortex which seems to be intensifying and the east European trough moving W/SW. How important will this be if the amplification, caused presumably by the Pacific wave train and the Aleutian HP ridging into the Arctic, is but transient and the Atlantic flow becomes flatter which the ext mean EPS is indicating?

It's isn't going to get more amplified days 10/15 though knocker

with 51 members, the drive back towards climatology will always lessen the anomalies and upper ridges/troughs where they are not generally found. The trend to sharpen the ridge and Atlantic anomoly days 8/12 continues with each suite - so far! 

 

[mulzy]

35 minutes ago, Summer Sun said:

 

The ECM Control is in the former category.  A beautiful run with a true Greenland High in the extended range (all FI of course!)

Edited December 23, 2016 by mulzy

[snowbunting]

Wow. Woke this morning to a Greenie high, Nly flow and a block to the altlantic in early Jan with both the ECM and GFS agreeing for once at 240hrs. Cold core and wild cards indeed. Im not so good at teleconnections, stratospheric drivers etc but what has changed in the models direction last few days?

 

Away to batten down the hatches in North Lewis. Storm Babs is knocking on our doors. 

[Frosty.]

10 minutes ago, karlos1983 said:

Not a bad 240 ensemble mean from the ecm. Nice height anomaly too. 

Yes karlos it's very encouraging, the best potential so far this winter which will hopefully translate into a very cold snowy spell early in the new year..it would be what long suffering coldies deserve!

[joggs]

Genuine question.With a big solar burst expected to hit the earth soon (don't know if it will have an impact on the jet etc),will or are the models programmed to take such things into account or if anything untoward happens,will they suddenly flip?.

 

[Ali1977]

1 hour ago, karlos1983 said:

@Ali1977 when did you say you were travelling away 

if it was me, I'd start thinking of an excuse. You never know, maybe the weather will stop you getting to the airport 

Joking aside, I am getting cautiously optimistic now, ECM upgrade seems to have been a good one, it seems to have performed pretty well of late. Not getting carried away as this is still way to far out, but the signs are good! 

 

02-06th, just about the worst time to go away!! Blooming typical but I did mention this a few weeks ago!! Models seem quite firm on something starting though.

[West is Best]

Hats off to UKMO which first showed a mid-atlantic ridge back on Monday. All three models have been flirting with this, but GFS and ECM have now gone from flirtation to engagement. That's not quite marriage yet and most of us will be a bit circumspect until they're walking up the aisle to meet us at the altar. We'll probably have a few jitters but I prefer cautious optimism to cautious pessimism. For sure the details will change but the block out west, especially if accompanied by a true Greenland High, is the route to happiness.

p.s. teleconnectily? 

 

Edited December 23, 2016 by West is Best

[knocker]

23 minutes ago, frosty ground said:

Perspective for what?

Are you comparing a 5 day average to charts that start part way through this period, slight confused.

I'm not comparing anything merely suggesting not to concentrate solely on the det run as the GEFS mean anomalies only show transient ridging of any intensity.

Edited December 23, 2016 by knocker

[nick sussex]

I think the high then topple scenario towards Scandi is the likelier option. It's hard to see any Greenland pressure rises lasting and after any topple it's whether we finally see low heights sticking around to the se.

The ECM and GFS have the same  broad pattern but the latter clears the PV away from Greenland which helps to get the high pressure further north. It's this movement of the PV which is the greater uncertainty rather than the initial first step upstream of amplifying the US trough.

Still too far out though to have strong confidence in the models finally delivering something wintry and given recent weeks best to be cautious until we see that PV movement agreed on across the outputs.

[chris55]

Ensembles trending in the right direction, though det and control mixed on the colder side. Still a long long way off in terms of timeframe so plenty of runs to get through before we can have any form of confidence in the eventual outcome.

 

[bluearmy]

7 minutes ago, West is Best said:

Hats off to UKMO which first showed a mid-atlantic ridge back on Monday. All three models have been flirting with this, but GFS and ECM have now gone from flirtation to engagement. That's not quite marriage yet and most of us will be a bit circumspect until they're walking up the aisle to meet us at the altar. We'll probably have a few jitters but I prefer cautious optimism to cautious pessimism. For sure the details will change but the block out west, especially if accompanied by a true Greenland High is the route to happiness.

p.s. teleconnectily? 

 

Confused by this WIB - are you talking the  30 day met office text forecast ??

[ITSY]

I know this isn't the place for IMBYISM, but I would like to refer people back to my post in early November which said that my going on holiday on December 27th would almost certainly herald a change...

[West is Best]

2 minutes ago, bluearmy said:

Confused by this WIB - are you talking the  30 day met office text forecast ??

No, it doesn't quite compare I know in terms of timescales etc. but their T144 chart had a clear mid-Atlantic ridge. I posted at the time whether they had spotted something which might become a trend the others would pick up. 

[Ali1977]

1 hour ago, karlos1983 said:

@Ali1977 when did you say you were travelling away 

if it was me, I'd start thinking of an excuse. You never know, maybe the weather will stop you getting to the airport 

Joking aside, I am getting cautiously optimistic now, ECM upgrade seems to have been a good one, it seems to have performed pretty well of late. Not getting carried away as this is still way to far out, but the signs are good! 

 

02-06th, just about the worst time to go away!! Blooming typical but I did mention this a few weeks ago!! Models seem quite firm on something starting though.

[BLAST FROM THE PAST]

Eye candy indeed fo coldies but I for one, due to the slug has controlled things, have very little confidence in the outcome. I think the ridge will be far less pronounced and will be a ridge that moves across the UK 

. Now let's see if that scuppers a mild outcome!

 

BFTP

[West is Best]

On 19 December 2016 at 16:38, West is Best said:

It's interesting to see that the 12z UKMO displaces the high at T144 much further west than GFS. The latter, with it's slug aka Bartlett tendency, then has knock on effects for subsequent developments. The UKMO actually has huge potential from here:

All eyes on the ECM which has had a dreadful few days and also on the FAX charts now.

Here we go. Back on Monday I thought there were the first tentative signs from UKMO of this trend. It wasn't a lot: just a whiff of a mid-Atlantic development perhaps.

[The Northern Ramper]

49 minutes ago, Kentish Snowman said:

So it's 4/5 for a cold Northerly or 5/4 for an unsettled Northwesterly?

Let's hope the favourite isn't pipped on the post!

That's a win win for me so expect the high to be too close to the uk.

[Frosty.]

The Gfs 6z shows a chance of a white christmas evening and night across scotland and the snow showers risk extends south across remaining northern parts through boxing day.

Edited December 23, 2016 by Frosty.

[frosty ground]

Not much has changed everything further west but this is to be expected and natural variation of the same theme, 

[frosty ground]

It looking good for a continuation of the last few runs

[SnOwFeSt]

This is turning out to be a slightly better run - the NH profile shows more heights into the pole and a greater ridge pumping up from the baring sea on the other side, which increases the change of a full split. Overall the same pattern so far into the run, so looks like things are remaining positive for cold in the new year at this stage.