Model Output Discussion: 12Z (22/11/12) And On...

[Met4Cast]

Can I just echo what John Holmes has been saying for weeks now.

Pay closer attention to the height anomaly charts than the operational models, they tend to have a better handle on things for the overall pattern. A few things worthy of a mental note

- Model disagreement over shortwave at T96

- Until the above is resolved, we're going to see a verity of different solutions post T96

- Overall pattern is still very blocked

- Too early to look at details

- Trend is cold

[bradymk]

Absolutely, it happens during most projected cold spells, amazing charts like yesterday only to be replaced by not so good charts today.

Same old = Prozac bottle. Why do members do it to themselves, I have no idea.

Also last night there was talk of how a breakdown would happen at +240 and how it worried a few, that's now forgotten and now we are worried about there even being a strong enough block to even breakdown...

Tomorrow there will be something different to worry about I'm sure.

As the more experienced and knowledgable members say: just get the cold here first and see what happens

Completely disagree, 12z GFS is a great run so far, so was the 6z. The GEFS Ensembles all point to a colder spell, also NAEFS Charts and the ECM Ensembles. UKMO is the only run at the moment that isn't the best but it is only one run. And the metoffice are also fairly confident of colder weather. So "amazing charts like yesterday only to be replaced by not so good charts today" i think is wrong but it is easy to be deflated while model watching but this is not one of those times, some great charts.

[The Eagle]

If the shortwave to the east of GL wasn't there it would be perfect

http://www.wetterzentrale.de/pics/Rukm1441.gif

[ITSY]

the evolution of GFS is great. UKMO not so but only goes to 144 and only 1 run. wait for ECM before casting judgement on the 12Zs. Even then, give it another 24/48hrs minimum. We're talking about changes mid next week. wait till late weekend or monday to have a firmer idea.

Yesterday I said that every frame from 186-384 gave leeds snow on 18Z GFS. On today's 12Z we have every frame from 174-336 at least. Stop complaining at some great charts. changes are GOING to happen.

Edited November 22, 2012 by ITSY

[No Balls Like Snow Balls]

What is the accuracy of the UKM @ 144hrs? I have a feeling (if i recall) it is one of the worst performers at that range?

GFS a corking beast from the east at 180hrs

UKMO is actually behind GFS and ECM @ day 6, the difference between UKMO and GFS is negligible though. Of course all models verify at different times so there is nothing to suggest UKMO is wrong tonight!!!

Edited November 22, 2012 by No balls like Snow Balls

[Bristawl Si]

Can't help but feel deflated today, lesson of the day, never get excited about what the charts are showing

No - lesson of the day (and everyday) is not follow every run and take them as 'given'.

The general trend is the key.

[Isolated Frost]

Good lord, please say these aren't the charts that are leaving people 'deflated'...

[Geordiesnow]

In fairness, looking at the UKMO on face value, it starts off ok but then the shortwave at 144 hours puts a spanner in the works, looking at the chart at face value, I don't think its fully conclusive heights will drop and the run still has potential.

In terms of the weather on offer, then maybe the UKMO is better as the winds are more NE'ly but unusally we don't have alot of cold weather to the east of Greenland therefore uppers will be limited and so will convection/snowfall whereas the GFS is a classic of riding out the awful cold cloudy and perhaps wet weather but you may get your rewards in the end with brighter colder convective(snow showers) set up.

As per usual, there will be changes in the details of each run and as I said last night, there could be some up and downs in this thread.

[Liam J]

Very nice 12z GFS, a finger of bitterly cold air extending from Scandinavia over the northern half of the country with lots of snow piling up should anything like that verify.

Long way to go folks......

[snowmadchrisuk]

It's not been great recently but its still a good model. In terms of the 144hrs we might get away with it those shortwaves might head into Scandi and with low heights over the Med the high cant sink.

It's not a disaster by any means, I think we have to accept that the models are having a hard time here!

We wait for the ECM but I wouldn't be surprised to see that come up with a different scenario!

It will be interesting to see if the ECM 240 last night really was saying no to a GL High, As you say tonight's will probably be a totally different scenario and will go to show that the 10 pages of excitement about a 240 chart last night are here nore there at that range when it comes to what will actually happen. Still overall I think were in for a 2 week minimum Cold spell where cold will reach all eventually , even you in SW France

[bradymk]

Can I just echo what John Holmes has been saying for weeks now.

Pay closer attention to the height anomaly charts than the operational models, they tend to have a better handle on things for the overall pattern. A few things worthy of a mental note

- Model disagreement over shortwave at T96

- Until the above is resolved, we're going to see a verity of different solutions post T96

- Overall pattern is still very blocked

- Too early to look at details

- Trend is cold

This is a great post, can not believe all the negativity in here. Johns guidance of using the height anomaly charts is great and so much easier and these are still pointing to colder weather. Also the 12z GFS is very good in my opinion. Everyone is complaining about the UKMO but it isn't that bad. The problem is that it seems that some people think that it will snow in the UK every day from December 1st to February 29th. Loving model viewing at the moment, some very nice charts to look at.

Ps I thought that the MO 16-30 day was very encouraging today.

Matthew

Edited November 22, 2012 by bradythemole

[snowmadchrisuk]

The UKMO is a good model and seeing as the (relatively) poor evolution sets in before 144 hours I think it would be wise to dismiss it; this is the case even if the ECM sides with the GFS. I say this as I can recall a couple of times when the UKMO scuppered cold chances against the ECM and GFS and it was proved correct. Saying this I'm not so sure where we'd go from that UKMO 144 hrs chart; I think we would possibly get to our destination but it sure would be the (un)scenic route around procedings!

Yeah but the UKMO shows what it does because of that annoying Short Wave, if that Short Wave is weaker or pushed further South on the next run then Heights will push back into Greenland. All the bad runs of the last week have been spoit by Short Waves moving East , and 9 times out of 10 they have gone by the next run ... I'm not saying it won't be as the UKMO suggests but it is way to soon for panic stations..

Regards

Chris

[snowmadchrisuk]

Also just quick , I have noticed that more and more runs are going for that direct NE'LY flow with Cold uppers , this is becoming a trend between 180-240 and if this happens there will likely be snow showers everywhere as it look like it would be a strong flow direct from a Cold source.

[summer blizzard]

Brilliant run from the GFS12z maintaining the consistency of the freezer being opened Friday..

[ITSY]

the netweather chartviewer shows 1-3cms of snow saturday night into sunday for many central parts...I think this is highly unlikely, but wondering what people think of that?

[Liam J]

But useless for us in the south as usual.

Perhaps on the 12z for those in the far south of the UK, but I expect the final outcome to look much different than charts post T200 hours. A bit premature to be writing anything off... The charts really couldn't look any better if it's cold & snowy weather you long for

[weather eater]

Fuss, fuss, fuss, so many small changes to get through to reach 120hrs without worrying about 144hrs, the UKMO will show something else tomorrow morning I can absolutely guarantee it. The GFS meanwhile sails along nicely, forget FI and remember it’s only the start of winter, so how good is this to get the winter ball rolling.

Forgetting the long term cold prospects for the moment, the pattern for the next few days is very worrying, some of you in certain areas won’t be bothering with driving in the snow, it will be steering your boats through the ice-flows that you will have to contend with, as there looks to be no let-up in the rain.

[UV-RAY]

Well another day and nothing that the models are showing convinces me otherwise that we won't be seeing a lengthy cold spell developing later next week/weekend. As for those worrying over shortwaves being the spoiler, well my advice is as yesterday, if the models are showing shortwaves at +48, then worry, until then enjoy the eye candy!

Edited November 22, 2012 by Seven of Nine

[andymusic]

here ya go - DEC 2010 all over again!!!!!!!!

(courtesy of Joe B)

[johnholmes]

Hate the 12z

one liner and why if you please?

cold air and a -10C 850 almost over the country at times. Yes its in a far time frame but it is in keeping with the 500mb anomaly charts.

sorry you may be one of the few that likes mild but some comment from you would help-please?

I also found it odd when the professionals are now 'on board' I think it the phrase some of you use. Now one run again and off some of you go worrying about something when forecasters are having a hell of a time deciding just where and how deep the low on Sunday will be.

Edited November 22, 2012 by johnholmes

[IDO]

Hate the 12z

Yes, I see where your coming from. Very little snow for south of Watford in that run. North centric, not great for the south. Still blocked at the end of FI, so mid December, maybe? You never know. All can change and will...

Edited November 22, 2012 by i'm dreaming of...

[Tony Beets]

Jimmny crickets, I can't believe the down and out feeling about the output!! Everything is still on place for a very cold period to develop, don't take every run as of that's concrete what will happen!! The models still don't know what will happen in the next 3 days so be patient and we will get rewarded.

[Isolated Frost]

Yes, I see where your coming from. Very little snow for south of Watford in that run. North centric, not great for the south. Still blocked at the end of FI, so mid December, maybe? You never know. All can change and will...

Erm, how do you see northerlies? The run is completely north-east to east based. I don't understand some of these posts- at least put a chart next to these statements.

[Cloud 10]

Good lord, please say these aren't the charts that are leaving people 'deflated'...

The only thing that should be feeling deflated is the Polar Vortex!!!!!

[The Northern Ramper]

What is the accuracy of the UKM @ 144hrs? I have a feeling (if i recall) it is one of the worst performers at that range?

GFS a corking beast from the east at 180hrs

I am interested in what the JMA has to offer more than the ukmo and Gfs, the model which our met office highly rate.