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

[feb1991blizzard]

A slight downgrade on the GEFS mean, sharper ridging on 12z compared to 18z.

12z

 

18z

 

[karlos1983]

P1, 10,11,15 all look fantastic at 192, almost all have the second northerly. 

[Jason M]

Well, at 192 the GEFS are totally behind a northerly. Whether or not it will be what peeps in here are looking for or something more akin to this weekend is impossible to say.

[feb1991blizzard]

Just now, karlos1983 said:

P1, 10,11,15 all look fantastic at 192, almost all have the second northerly. 

we need more than 4 members showing it at 192 though, needs to upgrade again over the next few runs, granted the Northerly will probably happen but I'm hoping for a quality Easterly afterwards and if things don't progress in the next few runs, the fat lady will be gargling her throat regarding that scenario I'm afraid.

[radiohead]

There are some very good GEFS members at T240 but there is very little support for the strong UK high shown on the OP for that time. Most of the members seem to be split between keeping high pressure further west or a flatter pattern with low pressure running over the top.

[Connor Bailey Degnan]

Well, i remain very optimistic tonight. Second Northerly plunge seems probable and probably lasts quite a bit longer than this initial 'tease'. Thereafter, EC32, JMA and many other LR back an easterly set up. Things looking up. Best January cold since 2012/13

[karlos1983]

3 minutes ago, feb1991blizzard said:

we need more than 4 members showing it at 192 though, needs to upgrade again over the next few runs, granted the Northerly will probably happen but I'm hoping for a quality Easterly afterwards and if things don't progress in the next few runs, the fat lady will be gargling her throat regarding that scenario I'm afraid.

Well they were just 4 examples Feb. Cheer up, the outlook looks good to me especially compared to winter so far. Opportunities exist for cold and snow. certainly no sign of the fat lady peeing on winter fireworks to me eyes. 

[feb1991blizzard]

Just now, radiohead said:

There are some very good GEFS members at T240 but there is very little support for the strong UK high shown on the OP for that time. Most of the members seem to be split between keeping high pressure further west or a flatter pattern with low pressure running over the top.

Yes, the one thing still in our favour is a shallow (expected at 264) trough over Italy though on the ensemble mean, while that is showing, we are still in the hunt, actually decent the further you go into the back 192 hours when at 192 it looked a downgrade.

[blizzard81]

A strange evening really. The ops have been OK I suppose but the thing I remember with prolonged cold spells is that once the ops lock on within the 10 day timeframe, the momentum takes over and upgrades appear at will. Today has been the opposite. The runs seem to have been watered down as the day progressed. This really isn't a good sign in my book. 

[Mucka]

GFS 18z short ensembles Central England show the 2nd Northerly just showing up at the end of the run with just a minority of members dissenting.

 

Boring graphs?

I give you eye candy!

Edited December 29, 2016 by Mucka

[TEITS]

Last one from me tonight.

After many years of following these situations I would like to make some suggestions.

As we can clearly see today the operationals can show a massive difference in the weather we experience on the ground here in the UK. So with this in mind I personally tend to ignore ensembles, height anomaly charts, teleconnection forecasts and just stick with following each operational run. The simple reason is again due to the UK being such a small bullseye when it comes to cold being backed W/SW from blocking to our E/NE.

[Southender]

5 minutes ago, blizzard81 said:

A strange evening really. The ops have been OK I suppose but the thing I remember with prolonged cold spells is that once the ops lock on within the 10 day timeframe, the momentum takes over and upgrades appear at will. Today has been the opposite. The runs seem to have been watered down as the day progressed. This really isn't a good sign in my book. 

True. But they were always going to water down from that Day after Tomorrow GFS 6z run this morning.

[Day 10]

P19 is the closest the the ECM 216 and goes onto to show what could happen... Purely for fun I may I add, as I consider FI 96-120

Edited December 29, 2016 by Day 10

[TEITS]

6 minutes ago, blizzard81 said:

A strange evening really. The ops have been OK I suppose but the thing I remember with prolonged cold spells is that once the ops lock on within the 10 day timeframe, the momentum takes over and upgrades appear at will. Today has been the opposite. The runs seem to have been watered down as the day progressed. This really isn't a good sign in my book. 

Don't agree.

Firstly after that incredible 06Z GFS run all tuns would be watered down. The 12Z GFS was very impressive with a classic E,ly and then we have the ECM which would certainly develop an E,ly thereafter. The only disappointing run is the 18Z which tends to be poor hence its name the "pub run".

[blizzard81]

Just now, Southender said:

True. But they were always going to water down from that Day after Tomorrow GFS 6z run this morning.

I should have said not withstanding that infamous run lol.

[feb1991blizzard]

Just now, TEITS said:

Last one from me tonight.

After many years of following these situations I would like to make some suggestions.

As we can clearly see today the operationals can show a massive difference in the weather we experience on the ground here in the UK. So with this in mind I personally tend to ignore ensembles, height anomaly charts, teleconnection forecasts and just stick with following each operational run. The simple reason is again due to the UK being such a small bullseye when it comes to cold being backed W/SW from blocking to our E/NE.

No criticism of that method as long as you don't use them to make 10-15 day predictions, unless all 3 consistently show an Easterly prevail over a number of runs.

[Jason M]

11 minutes ago, TEITS said:

Last one from me tonight.

After many years of following these situations I would like to make some suggestions.

As we can clearly see today the operationals can show a massive difference in the weather we experience on the ground here in the UK. So with this in mind I personally tend to ignore ensembles, height anomaly charts, teleconnection forecasts and just stick with following each operational run. The simple reason is again due to the UK being such a small bullseye when it comes to cold being backed W/SW from blocking to our E/NE.

Hmm, completely respect your views TEITS although I personally think the ensembles are crucial to putting the operational runs into the correct context in that crucial 6-10 day timescale. They need to be used in the right way and there is some skill to that but I'm going to have to disagree with you on this one..

Don't understand the logic in discarding most of the available information before coming to a view?

FWIW - Form horse looks like a northerly of sorts around day 8. Impossible to know what happens after that as too much uncertainty thereafter.

.

 

Edited December 29, 2016 by Jason M

[Mucka]

Last one from me until the graveyard shift.

Day 15 GFS ensembles (deepest of deep FI where climatology reigns supreme) around 75% of runs have some form of HLB/MBL (some cold, some not)

That is a very positive sign that further, as yet unseen cold shots/patterns, could be lurking into mid Jan and perhaps beyond.

Nice thought anyway

Edited December 29, 2016 by Mucka

[blizzard81]

2 minutes ago, TEITS said:

Don't agree.

Firstly after that incredible 06Z GFS run all tuns would be watered down. The 12Z GFS was very impressive with a classic E,ly and then we have the ECM which would certainly develop an E,ly thereafter. The only disappointing run is the 18Z which tends to be poor hence its name the "pub run".

The 06z run aside - which goes without saying really. As far as the gfs 12z run goes, the easterly doesn't appear until after day 10 which is too far out to have any faith. As far as the ecm is concerned, nobody can say for sure what it would show after day 10. Some of the ecm ops and gfs ops over the last 48 hours were showing much more promise with regards to prolonged cold.

[karlos1983]

Looking at the ensembles it seems the second northerly looks odds on to verify and then we start to see big splits appear. 

[radiohead]

Meanwhile in the near term, the 18Z HIRLAM shows -6 uppers sweeping into Scotland at T48, with dew points turning to freezing or below, rain turns to snow up north on Saturday evening.

[feb1991blizzard]

Good ensemble graph, loads of frigid runs.

[BLAST FROM THE PAST]

Well a quickie from me. Like for like runs....we are in a good place for me 06z to 12z is no downgrade.    Timing to be decided but I am very comfortable with a cold way forward.

Now we 19 spotless days and I said last day or so there surely should/must be repercussions from this.  Look NE for advected main cold thrust which could be very severe but from a 'trigger LP'.........always had/have that in my mind for this Jan.  Don't be too surprised with to-ing and fro-ing re timing of this, the set up says we have a chance here.  +4 c max temp forecast on Monday for London! on TV!.....make that 2c for outer areas  at best, not a bad start!!

 

BFTP 

[Downburst]

11 minutes ago, feb1991blizzard said:

No criticism of that method as long as you don't use them to make 10-15 day predictions, unless all 3 consistently show an Easterly prevail over a number of runs.

Having watched thousands of runs also, I would like to agree with TEITS. In this situation you'll have to wait for 72 hour forecast at best, 15 days using NWP in a anti cyclonic setup over the BI, building to the north is madness. Just relax and know heights will be high, according to NWP, and expect something cold.

 

[nick sussex]

Not liking this evenings trend with those Atlantic lows adding more complications and then the initial high not getting as far north which means we now have to rely on events further out to play ball. Assuming we're going to get enough amplitude at day nine and onwards when we're seeing less within T168hrs isn't filling me with a lot of confidence.

The ECM even if it verified at day ten is still likely to take the coldest air to the se and dry cold conditions are simply not going to cut it given most want to see some snow.

It's irrelevant what the GEFS might show at T240hrs, the lower resolution there isn't great for accurately modelling easterly set ups. The ops normally lead the way with these set ups with the ensembles following.

Overall today after a promising morning its been an underwhelming rest of the day and we need to stop the rot tomorrow. The northerly shown by the GFS 18hrs run isn't upto much and at that range it overdoes the depth of cold. Sorry to sound less than enthused, but a cold high isn't going to cut it after the last 5 weeks.

Lets hope for better tomorrow.