Model Output Discussion

[Bottesford]

Please continue to discuss the latest model output.

This thread is explicitly for the discussion of model output - please use other threads for other off topic posts.

Personal attacks on other members will NOT be tolerated in this or other threads.

Thanks and lets get back to talking about the weather

[Tim Bland]

Here is to a more civilised model discussion

I haven't seen this posted any where else so I thought I'd paste it here. It is from Ian Fergason and gives us an insight on the discussions prior to issuing the long range forecast. Interestingly they are more confident in the final evolution to an Easterly than how we actualy get there. Looks like it's a win win situation!

" Rather than me blather-on about it here, let me quote directly some salient expert thoughts from our latest (late morning) detailed Met Office briefing. I trust these 'snipped' passages offer suitable clarification on the collective thinking down in Exeter....

"4. Trend For Days 10-15: Lamb weather types are unbiased easterly with a below average Shannon entropy. Hence probably slightly higher confidence in this period than for day 6 to 7.5. Discussion: The deterministic models are well split for day 6 to 7, and the ensemble means have a col near the UK (showing a wide spread of solutions). Thus a very messy, temporary breakdown from the colder weather on day 6 to 7 (with low confidence in all detail). However, all ensembles want to bring back a southeasterly during day 8 to 10. Confidence is thus moderate for a return to a more continental airflow with a drop in temperatures. If anything, the signal for day 10 to 15 is even stronger, and backs the flow more to an easterly."

[NorthantsSnow]

Sounds like the UKMO ensembles are more promising for cold than the actual operational runs. We shall have to see if the 12z comes on board with a colder solution later.

[swfc]

Looking at several posts regarding the ukmo i think some are not looking at the big picture.Id not dismiss it and after looking at the ecm this morning anything could happen very quickly.Blocking looks nailed on but like a few have said its the position thats up in the air.At the end of the day its just weather and certainly not worth getting wound up over.

[Ben_Cambs]

Like I said earlier in the previous thread tonights output will be very important. The best case scenario tonight is that GFS 12z is similar to earlier, and ECM trends towards GFS, leaving UKMO a sitting duck in the middle of an icy lake. Then we will want good ensemble support later on tonight. It will be nice to if some of the other models trend towards GFS aswell, such as GEM, as that is a European model. Another thing we will want to see is the UKMO backing off from its earlier output, as for the 4th day in a row the Met's outlook is totally against its raw output. I think this will be a good set of runs, as I have found over the past few days especially with ECM that the 12z's are better than the 0z. We will wait and see

[The PIT]

UKMO goes for the even larger teapot return but seems to be on it's own. GFS in FI land decides to bring winds in from east south east rather than south west. Couldn't get a bigger contrast. It will be mild or cold take your pick. Ah the deciding vote ecm which is sort of half way house. So it could be mild, average or cold.

So everything to play for in FI land.

[Bobby]

The helter skelter is gearing up for the 12z runs... strap yourself in, might be quite a ride. Make sure there's no razor blades lying around.

[mcweather]

As S4Lancia said in the last thread. It is the block that will determine things over the coming days not the Atlantic lows.

Initially we are on the cusp between the two but all longer term signs point to the easterly coming. Bearing in mind that the real cold has never really been progged to arrive before next weekend I see little to worry about, yes we may have a slightly less cold blip at some point this week but then that's what you would expect if you are on the boundary between a block and the atlantic. Never the less longer term scenarios from all outputs suggest the block building west and/or north west. Patience is required but we will get there. Winter 2010 is far far from over.

[swfc]

I can't agree the UKMO is a shocker and we can forget about cold for a while if if verifies, thankfully at the moment there is a fair bit of evidence stacked up against it.

Maybe it looks a shocker for cold weather but it does not mean it wont pan out that way.????.It goes out to 144 hrs so who knows.I do suspect there are more qualified people than us programing the computers and producing the charts.???.All will be revealed when the weather does what it does.

[The Eagle]

My feeling about the 12z is that it won't match the 6z op run given the ensembles and other models this morning. I would be happy if we came close to this situation at 120hrs on the runs this evening

I also think those who are making silly and not knowledgeable comments about this model and that model being wrong are being very naieve.

[Tim Bland]

Maybe it looks a shocker for cold weather but it does not mean it wont pan out that way.????.It goes out to 144 hrs so who knows.I do suspect there are more qualified people than us programing the computers and producing the charts.???.All will be revealed when the weather does what it does.

According to the Met office senior forecasters "all ensembles want to bring back a southeasterly during day 8 to 10. Confidence is thus moderate for a return to a more continental airflow with a drop in temperatures. If anything, the signal for day 10 to 15 is even stronger, and backs the flow more to an easterly."

[Jason T]

AFTERNOON ALL, newby here well from looking at the posts, and looking through models am i right that most are suggesting that tonights runs are going to be nail biting stuff.

Its wierd how a week ago the models were not playing ball, then something dramatic change overnight i believe, Now we are back to square ONE .

[southbank]

well first of the 12z reeling out , chances are we are going to see "rollercoaster" type of model soultions for at least next 72 hrs so please try and refrain from saying " no easterly coming " or " beast is coming " such is the complex situation developing between teleconnection signals of a block and how that interacts with energy exiting from the us. if your a cold lover enjoy what snow feast may show up like yesterday 12z and 18z and equally hold off from wrist slashing .........this is going to the wire

[Frosty.]

So why are we still discussing the UKMO raw output - It was wrong.

The 12z runs should answer that comment, if the ukmo 12z op improves, it should stay on track thereafter but not long to wait now. Fingers crossed for a southerly tracking jet, undercutting lows etc and a bitterly cold snowy outlook.

[SP1986]

I think the problem with the models at the moment is they keep backing off and showing great scenarios and then backing off again, and it's in waves so it's being gradually put back. The majority of the models at the moment are showing something quite a bit different to the easterly that was being shown, within the reliable timeframe. I'm not going to even try to guess what might happen because it's too difficult to call but as many members have said, tonight runs, or indeed tomorrow may be fundamental in determining which way this goes.

[Tim Bland]

Bunch of Mystic Megs now are they?

I don't see how your in a posistion to make a statement that it is "wrong". It could be wrong.

Ok fair point, I should have said that the professionals believe it is wrong. Does the UKMO raw output go out as far as day 15? the metoffice state there is a very strong signal for an Easterly from day 10-15.

[Thundery wintry showers]

I agree with Ian Brown re the UKMO- the runs yesterday might have supported a slow evolution to an easterly but this morning's UKMO would almost certainly herald a spell of mild cloudy SW winds bringing frequent tropical maritime air, I reckon.

The UKMO has had a better record at T+144 in recent months but during the last couple of cold spells it has sometimes been too progressive at T+144 bringing SW'lys in, so I think cold/snow lovers should only be concerned if the UKMO sticks to its guns and either GFS or ECM this afternoon join the UKMO.

I don't think a full-on easterly is guaranteed by any means- it may well end up as a modified cold cloudy version as some ECM runs have suggested.

[Jason T]

well waiting soon be over.

[Iceberg]

T66 and the initial signs on the GFS 12Z are good.

[Snowyowl9]

My feeling about the 12z is that it won't match the 6z op run given the ensembles and other models this morning. I would be happy if we came close to this situation at 120hrs on the runs this evening

I also think those who are making silly and not knowledgeable comments about this model and that model being wrong are being very naieve.

For some reason I can get the GFS 0z and 6z run at the same time.

http://91.121.93.17/pics/Rtavn1441.png

http://www.wzkarten.de/pics/Rtavn1441.png

[ChartViewer]

well waiting soon be over.

To me the most critical Model period is coming into play....

1. Jet energy

2. Western extent of the Block

Those 2 factors are crucial one way or the other with reagrds to a Full Easterly

Regards

[The Eagle]

Ok fair point, I should have said that the professionals believe it is wrong. Does the UKMO raw output go out as far as day 15? the metoffice state there is a very strong signal for an Easterly from day 10-15.

Id say they have a model themselves that does but they primarilly rely on the ECM for longer range. In fairness ECM 00z seems appropriate for their forecast.

12z GFS coming out now and looks maybe even a slight improvement for prospects so far. Early days though.

[MR EXTREMES]

Ok fair point, I should have said that the professionals believe it is wrong. Does the UKMO raw output go out as far as day 15? the metoffice state there is a very strong signal for an Easterly from day 10-15.

i think to be honest you made a fair point in the first place and the comment made to you was yet another dig.

and if they are a bunch of mystic megs then maybe ian f and others that put time and effort into there post are all mystic megs nobody really knows if its 100% yet and comments like that dont help.

i think the general idear from the met office thinking is due to the good height rises they have the ability to see to medium range although it does not always pan out there record for medium range forecasting is very good.

now eyes down i want bingo tonight and have everything crossed the ukmo was just having a wobble.

[PubliusEnigma]

I can't agree the UKMO is a shocker and we can forget about cold for a while if if verifies, thankfully at the moment there is a fair bit of evidence stacked up against it.

I totally agree, I'm binning the UKMO because it has a mild[er] outlook for next week, any charts that show

a glimmer of hope for an E/SE'ly i'm pinning my hopes on. GFS is the best performer of late, and with the 8th event

only a little over a week away, a lot to be optimistic about for now.

[Iceberg]

T66 and the initial signs on the GFS 12Z are good.

T84 and GFS has not backed down...This is a big plus.

Should be a good run this at least in the slightly more reliable timeframe, also snow still on Tuesday for England.