Model Output Discussion

[Jason T]

Evening all. If the models are all over place, as they appear to be could it be the the systems are as nw home page states BATTLE LINES DRAWN. Getting any true readings would appear to be difficult at the moment.

[tinybill]

evening all i know its fantasy world but if this happens should be a little bit interesting

[phil nw.]

1st point the models do not use previous data/experience, there are guides on the NW site that explain how they work

2nd point where is this model uncertainty, the UKMO looks pretty similar to the GFS at 120hrs and the GFS has been consistent for that time period for quite a few runs now

3rd point I don't think the block is any more likely to effect us now than it did a couple of days ago.

Hi W.E.

I am glad that i am not alone in saying that.

I think this week`s pattern, ie.Block to the East and Lows to the West/N.West, were well modelled days ago and the output has been consistent regarding the overall sypnotics.

It was never projected to be anything other than a fairly average week for jan.temps.wise.

I think some posters are eager to find the next cold spell and are overanalyising output into next week.

Output have always varied beyond around the T144hrs timescale and this can cause frustrations when no consistent pattern is shown run to run.

Edited January 18, 2010 by phil n.warks.

[The PIT]

evening all i know its fantasy world but if this happens should be a little bit interesting

Charts like that will get Blast excited.

At the moment it's a case of pout on blind fold get a dart and take aim as far as the models are concerned. Very much uncertainly within a very short time period.

[yamkin]

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

http://www.wetterzentrale.de/pics/Rgme1321.gif

24hrs earlier than I thought.

Utter confusion in the model output at the moment with the block much stronger than initially progged.This what myself and a few others have been saying for a while.

Im sure I read someone saying there isn't any model uncertainity. Well the 0Z GFS had -12C upper temps 30 miles off tne Norfolk coast at +168. The 12Z GFS have this all the way back to Finland! Now that is what I call model uncertainity!!

I will add that the snow event on Wed its being pushed back further W with each run. At this rate the precip won't even reach the W!

TEITS, Are these Easterlies what you referred to a few weeks back? They look very Beastly don't you think

[nick sussex]

Well some good agreement this evening upto 120hrs with the Azores high ridging north but then after this the models look in a mess, however it does look like high pressure will be close by so it certainly looks like the Atlantic has been shown the door again, at least we won't have to hear any more nonsense about the Bartlett!

[KTtom]

TEITS, Are these Easterlies what you referred to a few weeks back? They look very Beastly don't you think

Those easterlies are sourced from northern Africa mate, don't think they will be quite as cold as last weeks

[ChartViewer]

Well some good agreement this evening upto 120hrs with the Azores high ridging north but then after this the models look in a mess, however it does look like high pressure will be close by so it certainly looks like the Atlantic has been shown the door again, at least we won't have to hear any more nonsense about the Bartlett!

To be honest Nick I accept that you were right and others re the Bartlett....However up to 3 days ago maybe less a Bartlett was shown on the Models and may return

Regards

CV

[phil nw.]

Looking at 12zGFS Ens.(warks.)

The op. was close to the mean and control on the 850`s up to day 6

http://charts.netwea...arwickshire.png

and stayed within the general cluster further out.

The op. was a big outlier showing low pressure day10-11, which was when the dartboard low showed.

http://charts.netwea...arwickshire.png

Many runs showed pressure fairly high next week.

http://charts.netwea...arwickshire.png

which seems to favour 12z ECM

http://www.wetterzen...cs/Recm2401.gif

One last thing the 2m temps.

http://charts.netwea...arwickshire.png

show beyond day 6 it`s a warm run with many members colder which might indicate again that ECM with it`s continental S.Easterly flow showing from day 7-8 may be the one to watch for.

Just to be aware on that SEasterly-the 850`s are not v.cold but the surface would be.

Edited January 18, 2010 by phil n.warks.

[Cloud 10]

Well some good agreement this evening upto 120hrs with the Azores high ridging north but then after this the models look in a mess, however it does look like high pressure will be close by so it certainly looks like the Atlantic has been shown the door again, at least we won't have to hear any more nonsense about the Bartlett!

Don't be so sure! those bartlett junkies will find their fix from somewhere.:lol:

In the supposed reliable timeframe it looks like parts of wales and the midlands are at the most risk of some frontal snow on wednesday.

Also some wintry showers for NE England and E Scotland with some cold upper air spreading in from the east.

[nick sussex]

To be honest Nick I accept that you were right and others re the Bartlett....However up to 3 days ago maybe less a Bartlett was shown on the Models and may return

Regards

CV

The Bartlett fiasco was started by a poster who I shall not name, for a high to be called a Bartlett it has to last not be a temporary high thrown up by upstream events which then get rid of it after a day or two. The Bartlett by its nature will keep repeating over a period of time as the jet maintains a sw ne flow, a one day high that resembles a Bartlett is not a Bartlett.It seems now that if people see a euro high or Azores high in a dodgy looking position for a day or two the Bartlett comments begin. If people want a good idea of a Bartlett then they can take a look at basically the whole winter of 88/89!

Please just trust me on this one, if there would have been a proper Bartlett showing up that looked like lasting I would have been the first to be reaching for the prozac and also warning the thread.

[TEITS]

Fasinating model output at the moment. My best guess based on all the model runs is an E,ly early next week followed by the possible chance of the block moving NW with a surge of bitterly cold N,lys into Scandi. Now exactly where this block goes to our NW will dicate how cold late next week will be. However at this stage I really fancy a decent cold spell towards the latter half of next week.

Most probably change tomorrow morning. :lol:

[SP1986]

The reality of it as far as I can see is that all models are showing a similar evolution it just ends up in different places. You have the GFS suggestion which drags SW'lies up and then the other end of the spectrum the ECM that has the pattern out further west and keeps UK under an inversion high.

The signals do suggest a similar pattern to what we did have but these can easily change along with the outputs. I would suggest the ECM has no more chance than the GFS and vice versa at this current time but they are the two extreme runs.

Unlike TEITS though I dont think cold is assured to be honest, if the pattern goes further east as per GFS things will be distinctly average.

[Skyhi]

Fasinating model output at the moment. My best guess based on all the model runs is an E,ly early next week followed by the possible chance of the block moving NW with a surge of bitterly cold N,lys into Scandi. Now exactly where this block goes to our NW will dicate how cold late next week will be. However at this stage I really fancy a decent cold spell towards the latter half of next week.

Most probably change tomorrow morning.

I agree!!...however, even though I am an absolute novice at all this weather watching, charts etc, the forecast on bbc news at six said the easterly cold is going to return???...does this mean literally or is it still a battlefield scenario on wed's?

[TEITS]

Unlike TEITS though I dont think cold is assured to be honest, if the pattern goes further east as per GFS things will be distinctly average.

Fair enough mate. I do admit the outlook is far from certain.

However I feel the Met O forecast for next week looks wrong already. At the moment next week doesn't look unsettled with near normal temps as instead we pick up a fairly cold E,ly flow.

I can see where they are coming from in regards to low confidence of it turning colder from the NE. This morning there was a definate shift in the ECM ensembles with many more colder members than last nights 12Z.

[cooling climate]

Fasinating model output at the moment. My best guess based on all the model runs is an E,ly early next week followed by the possible chance of the block moving NW with a surge of bitterly cold N,lys into Scandi. Now exactly where this block goes to our NW will dicate how cold late next week will be. However at this stage I really fancy a decent cold spell towards the latter half of next week.

Most probably change tomorrow morning.

Even though the CPC charts have for the moment backed off a tanking AO and NAO I really do think this is

more of a blip although it could well be more towards the end of the month before we see a real freeze set

in again.

I know its FI but the ECM t240 chart looks very tasty and the progression on from that would be very cold and

wintry and would also tie in with my thoughts as to how the next cold spell would develop.

The MJO looks to be getting its act together and we could very well see a rise in the AAM over the next few days.

[nick sussex]

The ECM De Bilt ensembles for the Netherlands show a continuing shift towards more colder members.

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

[Duane S.]

The Bartlett fiasco was started by a poster who I shall not name, for a high to be called a Bartlett it has to last not be a temporary high thrown up by upstream events which then get rid of it after a day or two. The Bartlett by its nature will keep repeating over a period of time as the jet maintains a sw ne flow, a one day high that resembles a Bartlett is not a Bartlett.It seems now that if people see a euro high or Azores high in a dodgy looking position for a day or two the Bartlett comments begin. If people want a good idea of a Bartlett then they can take a look at basically the whole winter of 88/89!

Please just trust me on this one, if there would have been a proper Bartlett showing up that looked like lasting I would have been the first to be reaching for the prozac and also warning the thread.

Good post Nick, A true Bartlett would only be able to form and remain with North Atlantic and Arctic oscillations playing ball (or not as the case may be). I suppose there are ways of getting one with just one or the other in place but not as likely.

88/89 DJFM period

AO average +2.4 (the highest 4 monthly period on record, or at least since 1950. Although unsurprisingly 1989/90 JFMA ran it close)

NAO average +1.4

compare that with...

62/63 DJFM period

AO average -1.6

NAO average -1.2

09/10 D only

AO December -3.4

NAO December -1.9

Edited January 18, 2010 by s4lancia

[mcweather]

The ECM De Bilt ensembles for the Netherlands show a continuing shift towards more colder members.

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

Thanks for posting those Nick. Seeing as the ECM has been by far and away the best medium range model so far this winter. Its good to see it progging more cold runs again The operational was actually on the milder side of things too. Interesting times ahead.

[Ben_Cambs]

Great ECM ensembles tonight, grudually more colder runs... An interesting GFS 18z tonight aswell, hopefully a backtrack from the previous run...

[damianslaw]

Short term - trending colder especially in eastern parts by Wednesday with 528 Dam air flirting with the NE coast.

I don't think the models have got Wednesday right just yet with regard to the front, a matter of 50 miles east or west will make all the difference for central parts, as to where any snow falls. Generally it looks like it will be very wet snow so whilst it may come down thick and fast it will be thawing at the same time, can't see it causing too much of a problem except on higher ground.

Thursday is looking like the wettest day many places will have seen in a long while, potential for a couple of icnhes in western parts and with strong winds it will come as a bit of a shock for many even though temps for a time will become quite mild.

Towards the end of the week, pressure rising over the Azores and building north into the atlantic, which will quickly cut off the milder flow and bring us increasingly into a continental flow once again, with a light easterly I imagine developing by the end of the week, so a settled weekend looks on the cards with average temps.

Next week, I forsee it turning increasingly colder as we see heights retrogress north west to Greenland, NAO and AO trending negative, PV moving out of Greenland and plenty of WAA moving up the west side of Greenland, a quiet atlantic, extra energy going into the southern arm of the jet all conducive to the development of a scandi trough pulling in some bitter arctic air before the months end. The atlantic is looking very very quiet, if it was ever going to get its act together it would be now, alas it has an almighty block to the east, this is turning out to be a winter with true cold lover synoptics..

[weather eater]

Hi W.E.

I am glad that i am not alone in saying that.

I think this week`s pattern, ie.Block to the East and Lows to the West/N.West, were well modelled days ago and the output has been consistent regarding the overall sypnotics.

It was never projected to be anything other than a fairly average week for jan.temps.wise.

I think some posters are eager to find the next cold spell and are overanalyising output into next week.

Output have always varied beyond around the T144hrs timescale and this can cause frustrations when no consistent pattern is shown run to run.

Thanks for that Phil, what I find frustrating is that we have enough really varied and interesting evolutions being churned out by the models from the mid range, that there's no need to over analyse those small short range variations, that are after all just part of normal model behaviour.

While the ECM is an interesting run, for me it just demonstrates again that the models are struggling to establish a clear trend, it seems almost anything could happen.

[nick sussex]

Short term - trending colder especially in eastern parts by Wednesday with 528 Dam air flirting with the NE coast.

I don't think the models have got Wednesday right just yet with regard to the front, a matter of 50 miles east or west will make all the difference for central parts, as to where any snow falls. Generally it looks like it will be very wet snow so whilst it may come down thick and fast it will be thawing at the same time, can't see it causing too much of a problem except on higher ground.

Thursday is looking like the wettest day many places will have seen in a long while, potential for a couple of icnhes in western parts and with strong winds it will come as a bit of a shock for many even though temps for a time will become quite mild.

Towards the end of the week, pressure rising over the Azores and building north into the atlantic, which will quickly cut off the milder flow and bring us increasingly into a continental flow once again, with a light easterly I imagine developing by the end of the week, so a settled weekend looks on the cards with average temps.

Next week, I forsee it turning increasingly colder as we see heights retrogress north west to Greenland, NAO and AO trending negative, PV moving out of Greenland and plenty of WAA moving up the west side of Greenland, a quiet atlantic, extra energy going into the southern arm of the jet all conducive to the development of a scandi trough pulling in some bitter arctic air before the months end. The atlantic is looking very very quiet, if it was ever going to get its act together it would be now, alas it has an almighty block to the east, this is turning out to be a winter with true cold lover synoptics..

Good post Damian :lol:

The later output is of course very interesting as the PV looks to drop south, its difficult though getting the perfect set up, we often see the PV heading se'wards and not south. Overall though the output looks very encouraging.

[Cecil Hogmanay Melchett]

Great ecm and ensembles this evening.

I note with interest certain members not postig this evening after going into overdrive with the mild charts over the last few days.

Thanks also to nick sussex who pointed out the absurdity of bartlett high rubbish being sprouted in here recently.

WOW i just looked at the ecm ensembles again man they are HOT!!!

[beng]

Seems to me there are some interesting similarities between http://www.wetterzentrale.de/pics/Recm1201.html and Feb 2nd 1991 (and all that followed a few days later) - perhaps the main difference in 91 was that there was a stronger polar vortex in SW Greenland helping drive the WAA, but I'd say we're getting very close to a real Beasterly at the moment.