Model output discussion 25th Jan - The final third of winter beckons..

[The Weather Dragon]

regarding model confidence this winter i tend to go in this order

UKMET, GFS/GEM, ECM 

[Paul_1978]

46 minutes ago, abbie123 said:

The backtrack begins today I'm afraid I love heavy snow but I do feel ecm could be correct some cold air coming in from east but mainly dry maybe some snow showers in south east England but mainly cold and very dry I hope I'm completely wrong.

Why do you feel the ECM could be correct? I think it's been inconsistent this winter myself. 

[warrenb]

14 minutes ago, Ali1977 said:

What do we make of these tweets...I'm unsure.

Well if you actually showed what he was replying to it would help. Someone said the ECM was disappointing this morning, hence the comment above which is basically saying Main and Control in small cluster, main emphasis on what meto is showing out to day 10. Although Meto seen as a little fast with retrogression signal.

Edited February 3, 2017 by warrenb

[Tim Bland]

Not too worried about ECM after seeing the below. 

[Iceberg]

8 is a very small minority cluster so that's 8 out of 50. 

Gfs had similar clustering. 

So a pure probability combining the gfs and ec ens might be 

30% deep cold of 850s below -10. 

35% cold and dry with 850s -4 to -8. 

20% as above with more instability and Atlantic influence but still periods of cold weather. 

15% quick breakdown after rather tepid 850s 2-3 day cold spell. 

Meto going with majority cluster of dry and cold for now. As per meto forecast for me that has 3c midday on Thursday next week with an easterly and feeling like -1c

[Tristrame]

1 minute ago, warrenb said:

Well if you actually showed what he was replying to it would help. Someone said the ECM was disappointing this morning, hence the comment above which is basically saying Main and Control in small cluster, main emphasis on what meto is showing out to day 10.

Basically he's saying the met office think overnight output doesn't change where we're more than likely heading and that's a cold or very cold continental influence 

If you ever read the U.S technical discussions on how they put a forecast together (they're publicly available on wundergound) you'll see them dump one model in favour of another or blend them together with a human decision 

It goes on all the time 

It goes on here in this forum 

People looking at weather tools for years  or decades have the experience to call these things

Hence never despair with what one run shows 

 

[Man With Beard]

6 minutes ago, Tim Bland said:

Not too worried about ECM after seeing the below. 

Worth bearing in mind that at D10, the best verifying chart, I believe, is the ECM mean (not op) - and quite recently someone showed that the GEM op is outperforming the ECM op at D10 too.

I think a wise view is this: D5-D9, varying between cold and very cold with snow opportunities for some. D10 onwards, highest chance is of a gradual sinker but probably taking several days to clear cold from the south, so far slower than ECM op is making out. Small chance of a better split jet and renewed easterly.

[weirpig]

13 minutes ago, The Weather Dragon said:

regarding model confidence this winter i tend to go in this order

UKMET, GFS/GEM, ECM 

I agree with that comment Dragon,   For me the ECM has often been full of promise this winter and has yet hasnt really verified   UKMO  has been very good this winter.   For me at the moment a dry easterly is probably favourite    but has ever things could well change for the better

[joggs]

49 minutes ago, phil nw. said:

The problem wrt the Strat warming it only gives a limited window for Arctic blocking before the vortex will reform.We are a bit unlucky with this one in the way the  trop. vortex has split leaving the main segment to our north west so the Scandi block is always under pressure from the west.

Looking at this mornings outputs we still look likely to go colder next week but the Scandi high is shown to extend south cutting off the supply of deep cold

so this phase of cold looks to be more likely to be a dry and cold continental south easterly.We do need to see better trough disruption heading into southern europe before we lose the block otherwise the chance of a deep cold easterly will disappear. 

To me the pv as been a limpet to the usual blooming place and poorly aligned for any disruption.And eventually putting pressure on the scandi high which is not been able to retrogress and I feel eventually ebb n flow around us.

I'm writing this winter off as one of the most irritating for what promised to give us better chances of cold.

Only been honest.

[Ali1977]

Over too the 06z then, no backing the ECM op please 

[TEITS]

Have to be honest I have sat shaking my head at some of the posts this morning. Let me address a few points.

As I said a few days ago the positioning, orientation of the high and associated cold pooling will change even inside +72hrs. At the moment the E,ly finally arrives at +120. So far only a few runs have indicated bitterly cold E,lys with widespread snow showers. The general trend has been around -10C with snow showers affecting only E areas. This could change though based on what I said above.

The longer range i.e mid Feb continues to look interesting. The GFS in particular has often suggested the holy grail of cold winter synoptics with the block to our NE extending W into Greenland. This mornings ECM from +192 to +216 looks very dodgy to me.

Finally I want to address some of the tweets that appear on this thread. Correct me if im wrong but didn't MVH only recently say the first 2 weeks of Feb is likely to be mild and very unsettled? Also Ian F only a few days ago said the ensembles suggested an E,ly is unlikely, at the same time I was saying the operationals are leading the way and too ignore the ensembles!

[Ali1977]

8 minutes ago, TEITS said:

Have to be honest I have sat shaking my head at some of the posts this morning. Let me address a few points.

As I said a few days ago the positioning, orientation of the high and associated cold pooling will change even inside +72hrs. At the moment the E,ly finally arrives at +120. So far only a few runs have indicated bitterly cold E,lys with widespread snow showers. The general trend has been around -10C with snow showers affecting only E areas. This could change though based on what I said above.

The longer range i.e mid Feb continues to look interesting. The GFS in particular has often suggested the holy grail of cold winter synoptics with the block to our NE extending W into Greenland. This mornings ECM from +192 to +216 looks very dodgy to me.

Finally I want to address some of the tweets that appear on this thread. Correct me if im wrong but didn't MVH only recently say the first 2 weeks of Feb is likely to be mild and very unsettled? Also Ian F only a few days ago said the ensembles suggested an E,ly is unlikely, at the same time I was saying the operationals are leading the way and too ignore the ensembles!

I agree ref the tweets, the pro's haven't done too well - well their computers. But shouldn't discount their tweets. Far more knowledgable than many on here.

Ians comments on this forum are missed by many so that's why I post some of his tweets, if not the whole conversation which would clog this up 

Edited February 3, 2017 by Ali1977

[Scandinavian High.]

17 minutes ago, Paul_1978 said:

Why do you feel the ECM could be correct? I think it's been inconsistent this winter myself. 

I think is where I have been let down so many times with easterlys over last few winters at last minute they have been watered down to dry or the odd snow flurrie hope I'm wrong anyway here comes 6z.

[Devonshire]

15 minutes ago, Tristrame said:

If you ever read the U.S technical discussions on how they put a forecast together (they're publicly available on wundergound) you'll see them dump one model in favour of another or blend them together with a human decision 

It goes on all the time 

It goes on here in this forum 

People looking at weather tools for years  or decades have the experience to call these things

Hence never despair with what one run shows 

... and to continue the logic: never despair (or be overly optimistic) over what one official agency or 'expert' forecasts at any particular time!

[JamesL]

I for one am very pleased with where we are today. 

Go back 5-7 days and see where we were! Staring down the barrel of a limpet PV and a succession of Atlantic driven drivel. 

As TEITS alludes to, historically Scandinavian highs are notoriously difficult to pin down. Yes the general theme can be but the devil is in the detail even at 72-96hrs. 

To have the general agreement on a theme 5-7 days out on ALL the NWP is VERY encouraging indeed. 

Now the ens have smelled the coffee we can see the means are pretty impressive for the next 10 days. When have we had this kind of cross model agreement on this kind of "cold" setup?!? Probably not since 2010! 

So for me I'm now looking within the 120h timeframe as anything else (regarding uppers, cold pools, instability etc) won't be resolved until 48/72h 

James 

[Neilsouth]

1 hour ago, Paceyboy said:

The ECM is not a concern for me. Contrary to its reputation it's actually been very unreliable. Like the most overrated football player. Actually  we shouldn't give it so much weight after 120h. As others have said as long as UKMO is interested then we can feel a bit more confident.

Hope to see upgrades from now on as we are approaching the most important time where things can go wrong, in this case as blue army said 3 days out

 

This is true, a lot of people have following the ECM during the last few months and yes I agree with you as the UKMO has been on top form.

[The Weather Dragon]

In general very pleasing model output this morning. All 3 main models show some continental influence next week. As TEITS mentions Scandinavian heights are a difficult concept for the models - is the atlantic overplayed - probably

The 'fly in the ointment' as in previous let downs may be the azores high - if we can send that packing we could be in for a lengthier spell of below average temperatures - one to watch over the next few days.

In conclusion - plenty to be optimistic about. The winter champion UKMET is with us for now - this is the model to watch. Enjoy !

 

Edited February 3, 2017 by The Weather Dragon

[Daniel*]

37 minutes ago, joggs said:

To me the pv as been a limpet to the usual blooming place and poorly aligned for any disruption.And eventually putting pressure on the scandi high which is not been able to retrogress and I feel eventually ebb n flow around us.

I'm writing this winter off as one of the most irritating for what promised to give us better chances of cold.

Only been honest.

Well the 'beast' did not stop the brutal cold in 1991 similarly to now no -NAO some good orientated +ve heights over to Scandinavia with lower heights to the S can work wonders for us - immaterial to what goes on to the west of us. You can see some distinct similarities really to to where we are now. Once we have the scandi block in place which is evident as soon as D3-4 it will not be inclined to leave the scene. The models are notorious for bringing its downfall too quickly - there isn't the fluidity which some models are presently showing. I think we will see a 7 day cold spell I don't see it being a brief cold encounter. A rerun of 1991 is unlikely well the depth of the cold but broadly pattern wise perhaps not.

Edited February 3, 2017 by Daniel*

[Tristrame]

29 minutes ago, Ali1977 said:

I agree ref the tweets, the pro's haven't done too well - well their computers. But shouldn't discount their tweets. Far more knowledgable than many on here.

Ians comments on this forum are missed by many so that's why I post some of his tweets, if not the whole conversation which would clog this up 

To be fair to MVH and Ian F

Theyre only reporting what the tools in front of them (and in Ian F's case Met office internal discussions) say in a character limited tweet 

Models are changing every day though like the weather pardon the pun so you'd expect Ian F and MVH to do likewise 

 

 

 

Edited February 3, 2017 by Tristrame
Word 'say' missing

[Iceaxecrampon]

00z

Class.

Ppn just sits there on the East Coast.

One to watch if the blocking loses out -  then showtime.....

Plenty of easterly activity in FI  - but thats FI

[Weathizard]

Frustratingly stuck in no mans land at 132, Atlantic can't undercut and can't move as the Scandi high exerts its pressure, looks like a waiting game to see if we can shear that low

[Snowman.]

6z shows the high trying to loop round to Greenland. bigger forcing on the incoming Atlantic.

 

[jvenge]

GFS 6z at T144

[chris55]

Block held to far east on the 06z for any meaningful cold to move in by day 7. Perfectly plausible solution.

[Guest]

EUROPEAN TEMPERATURE AND PRESSURE CHECK

In the build up to phase 1 of next week’s “probable” cold spell, I feel that it will be useful to keep up-to-date with the current and trending  temperature and pressure changes in Europe. I will try to produce these on a daily basis for the next week or so. This should help to show if the pattern is likely to evolve favourably (for coldies and snowies) and to monitor the extent of the cold that we might expect.

Firstly, just a brief comment on the current model output.  Expect further adjustments in the D4 to D7 period. This is a complicated pattern transition with changes in the strength and path of the Jet Stream, questions over how quickly the Scandinavian HP builds, exactly where it sets up and its orientation, to what extent will Atlantic LPs undercut the HP and the position of any LP in the Mediterranean. Remember this is all in phase 1. With another (one or two) warming impacts likely to follow in the D10 to D15 period and well beyond that period. Phase 2 may well be stronger and have longer lasting impacts. There is a suggestion of a switch from easterlies to northerlies later on, especially when the predicted MJO goes through the key phases 7, 8 and 1 in much higher amplitude. The models are likely to struggle with the transition. It may be a continuation of the cold spell or there might be a very brief milder interlude. Even if the easterly fails to deliver deep cold and some snow, this may well turn out to be the precursor to a proper cold spell. Of course most of us would like to see both phases produce an epic cold spell!

EDIT: Whilst writing this I see that @Tamara has provided one of her excellent updates which is again highly encouraging. Come on everyone let's really enjoy all this unfold. The next 6 weeks are going to be the best period of model watching since at least March 2013 and probably November/December 2010. Now let's see if we can have a memorable cold spell.

Some of you will have been following my recent posts on the “Euro block” and I shall pick up from my last one on page 43. This took us to February 1st.

European Surface Temperature Charts:

                    Current "live"                                              Feb 3rd 0650                                               Feb 2nd    1250                                                 Feb 2nd  0650      

                           

Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the mins and the 1250s are usually close to maxs.

The cold pool has become more extensive and deeper again over north-west Russia as can be seen by comparing today's 0650 chart to yesterday's. Colder conditions are spreading back slowly south-westwards through south Germany, Switzerland and into south-east France. Steady as she goes in Scandinavia.Temperatures have eased slightly in south-east Europe                            

GFS 6z February 3rd T+6 European Charts:              

               2m Surface emps                                                 850 Temps                                               500 hPa Temps

               

A nice pool of -20 850s over western Russia.

European Surface Pressure Charts:

                   Current "live”                                                 Feb 3rd 0650                                             Feb 2nd    1850                                              Feb 2nd  0650                          Current Met Office Fax: 0600 Feb 3rd                                                  

                               

The HP block on the eastern European and western Russia border has hardly changed over the last few days. The main centre remains just south of the Black Sea. There is a strong ridge northwards through western and north-western Russia right up to the east of Scandinavia. It is this ridge which is predicted to link with a new cell of HP moving down from the Arctic and then towards Scandinavia. This is the one to watch. 

EDIT (1030):

@Nouska I do hope that your roof doesn't blow off! It looks like it'll get pretty bad down there with gusts already over 100 kph in Biscay and 84 kph in Bergerac (and over 90 kph nearer here in the south-west approaches). I should imagine that you have lost (or will lose) your power (as you often do). A lack of a post by you today would be an indication of this. Fingers crossed that you do not suffer too much damage.

UPDATE (1145): I see from your recent "likes" that you are still in touch with the outside world!  There is a rare "red warning" for wind in second storm for tonight with winds of up to 160 kph on the coast and 130 kph inland. Good luck to you and @nick sussex

WIND WATCH - "LIVE" WIND GUST CHART                 FORECAST AVERAGE WIND SPEEDS                  RED WEATHER WARNING FOR WIND

                                           

Edited February 3, 2017 by Guest
Correcting typos and to ensure that all the links and charts work properly.