Model Discussion Thread - 15th Jan

[Southender]

possibly the BEST WAA chart in history

http://modeles.meteociel.fr/modeles/gensp/run/gensnh-6-1-240.png?12

S

Love it. All hail PTB 6. Let's hope this one is the winner!

[Zenarcher]

Review on the weather models this evening

GFS

All models agree with the GFS up to 96 hours with the ridge in the Atlantic just to the South of Greenland. Its good to have the GFS finally move into this direction and agree because we now start to feel confident about this. At 120 hours the GFS has the ridge a bit more to the East than any other model so I suspect it should move a bit West over the next run or two but still very good agreement up to this time with all the other weather models. 144 hours this evening is where all the models start to go in different ways however its good to see agreement up to 120 hours much better than previous days when disagreements were happening as early as 72 hours. The GFS for the end of the month has a good outlook for cold weather it may start off mild but it will eventually get colder during the last week of January.

JMA

Has good agreement up to 120 hours after this its long range isn't too great looking, mainly mild in the South and unsettled in the North, we see heights rising to our North East but with PV around Iceland its not letting anything head our way.

ECM

An improvement from this morning. Good agreement to 120 hours. After this and into the final week of January it shows excellent cold weather for all the UK you could say it is the run of the day. Remember the ECM has been very consistent with this sure there have been some ups and downs but overall its pretty much kept the same outlook.

GEM

Another model this evening showing better charts than its morning run. It attempts to make a stronger blocking at 144 hours while the UK mainly Eastern parts see cold weather.

NOGAPS

Shows something similar to GEM at 144 hours but makes an even stronger blocking allowing a bit more colder weather to go into the UK. The NOGAPS this evening shows very nice charts for cold weather.

UKMO

Pretty much sticks to what it has been saying for a few days now and supports the other models up to 120 hours. At 144 hours it shows something like GEM and NOGAPS with a blocking and cold weather across the UK.

Overall tonight for the first time in a while we see good agreement with all models up to 120 hours which gives us higher confidence on what to expect over the coming days. The GFS has finally moved over and agreed in the short term outlook. I would think our best bet to what happens after 144 hours is something along the lines of the UKMO, GEM and NOGAPS since they show a very similar outlook meanwhile JMA, ECM and GFS take different routes each with not much support.

ICELAND and FAROE ISLANDS Storm: All models are showing a very deep and tight depression within this area on Tuesday night into Wednesday hurricane force winds can be expected, model agreement is good on the path but depth is unknown at this time. Interestingly the ECM is the only one not showing a deep low within that area something new comers may find interesting on how we can have disagreement at just 48 hours.

Tonight to Thursday: Cold and frosty tonight with a strong breeze over Western areas. Monday and Tuesday will be settled in the South but unsettled in the North. Wednesday unsettled and perhaps wet and windy in most areas with the far North of Scotland starting to see cold weather move in. Thursday similar to Wednesday but colder weather moving in over most of Scotland.

Friday to Sunday: On Friday Scotland and Eastern parts of England will see cold weather meanwhile the West of Ireland and England looking a bit warmer than the East and a bit windy. Saturday much colder for almost all of Scotland and England. Western areas again will be slightly warmer and windy. Sunday looks colder for all parts and Western areas should eventually see colder conditions as well. A strong breeze across the country and windy over higher grounds.

Sunday and Beyond: From the model agreement tonight it looks like we should see cold weather and wintry weather during the end of the month.

[SMU]

http://modeles.meteociel.fr/modeles/gensp/run/gensnh-19-1-384.png?12

Found it... its OK we can rest east- for all the fussy ones theres your 1080 MB record breaking Greenland high...

S

[Matty M]

I think it is in times like this where people can actually over analyze things. I think the best approach recently would be to go by one time period run day to day. So say look at the 12z runs once each day.

People inspect every chart update, every perturbation microscopically.

I don't believe this is the best method.

I think that's why the MetO make the best forecast, they look at things in a 2-3 day basis when making their forecasts and then come to a consensus forecast of the highest probability outcome.

Perhaps the over analysis of each run on here fogs our picture of the overall view.

[Matty M]

12z ECM Update EPS.

Well an absolute array of solutions at T168hrs.

I wouldn't even bother break it down into ratios.

Uncertainty is very high.

Edited January 15, 2012 by Matty M

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

this might upset the cold lovers on here i know it can go mild or cold but for me at the moment any hope of any snow looking on here the best i can see is F1 372 ,384 hours. any sign for the east coast at the moment

[Eskimo]

http://www.meteociel...?mode=2&ech=204

this might upset the cold lovers on here i know it can go mild or cold but for me at the moment any hope of any snow looking on here the best i can see is F1 372 ,384 hours. any sign for the east coast at the moment

You're going by those useless snow prediction charts?

[SMU]

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

tight clustering... mean around freezing..

If there was a model that showed that jet at 120 with a huge hang back digging South it would be the OP 12z ECM.....

s

[colboy]

Phew what a week with the models chopping and changing about, but at least there is agreement of some very cold weather for next weekend, even Countryfile mentioned it..

I don't come on here that much but view the forum on a regular basis.

I would like to thank the mods for controlling this forum today after the bickering of the last couple of days.

[swilliam]

Blimey im on and off this fence like a yoyo.

Much better runs and finally the GFS has woken up and realised it was wrong. Im also posting the NOGAPS at +180 because its a scenario I suggested yesterday that could well occur.

http://modeles.meteo...0-180.png?15-17

This morning I said there was a divergence of 9C between the ensembles but this has now changed with a solid clustering around -5C.

http://cdn.nwstatic....bridgeshire.png

Yes I pointed out the ensemble cluster from 20-23 Jan this morning with the op out of kilter - nice to see it is following its ensemble!

[BLAST FROM THE PAST]

You're the voice of reason on here Stephen.

The ECM run is an improved but doesn't show anything special and it is showing the best synoptic of all operationals this evening.

Only improved from its wobble. It is heading back towards its better output and guess what...so are the other models.

Posted Today, 11:35

It's a shame that all the best posters on here who have made a good case for the uk to undergo a pattern change are possibly going to have the rug pulled from under them, the models this morning are back to where they have been for the last 6 weeks minus that rather colder zonal spell during mid december, relative riches compared to what the models are currently indicating for the next few weeks, still it could just be a model wobble on a large scale as I assume the background signals are still the same.

Maybe it was a wobble...but Karl maybe your new Pseudonym should be G F S? :winky:

So tomorrow we get to the 96/120 period...we head back towards the right direction...if the change comes it could be long lasting...yep I think 86 too

BFTP

[nick sussex]

I think it is in times like this where people can actually over analyze things. I think the best approach recently would be to go by one time period run day to day. So say look at the 12z runs once each day.

People inspect every chart update, every perturbation microscopically.

I don't believe this is the best method.

I think that's why the MetO make the best forecast, they look at things in a 2-3 day basis when making their forecasts and then come to a consensus forecast of the highest probability outcome.

Perhaps the over analysis of each run on here fogs our picture of the overall view.

Yes but what else is there to talk about in a model discussion thread?

Isn't that the point and thats why this place is busy as everyones looking at each output.

Maybe I'm missing something but isn't the whole point of being a model anorak the picking up on small details that could turn an output in one direction or another.

As it is all my friends think I need help and with comments like why are you so obsessed with snow and the weather and why do you spend so much time on netweather!

[bluearmy]

looking at the ecm ens mean charts, plenty of options on the table into fi and the scandi height rise looks like one of the more obvious.

[Duane S.]

Always nice to see the op and the control following the same path as well.

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

[Osbourne One-Nil]

I think it is in times like this where people can actually over analyze things. I think the best approach recently would be to go by one time period run day to day.

That's like me saying people are too grumpy and they should lighten up. I hope your post was heavy on the irony?

[Matty M]

http://www.knmi.nl/e...M_06260_NWT.png

tight clustering... mean around freezing..

If there was a model that showed that jet at 120 with a huge hang back digging South it would be the OP 12z ECM.....

s

Take a look at the postage stamps, a large variance of output at T144 and T168 for the UK. Those charts are for De Bilt and don't show the whole picture in the variety of outcome illustrated in the Postage stamps

Just thinking back to when the ECM used to have the stamps as the freebie and we used to think it was Christmas come early!

Edited January 15, 2012 by Matty M

[Matty M]

Always nice to see the op and the control following the same path as well.

http://www.knmi.nl/e...M_06260_NWT.png

There is more to it than meets the eye, check my post

[SMU]

Matty I cant be arsed to look-

One comment on the mean that is VERY important-

if you have 2 clusters both going in 2 different directions- IE one blocked & one not blocked the ensemble mean is useless!

S

[Matty M]

Matty I cant be arsed to look-

One comment on the mean that is VERY important-

if you have 2 clusters both going in 2 different directions- IE one blocked & one not blocked the ensemble mean is useless!

S

Just scan through them all, takes a minute. It shows the variance well!

[snowwonder]

Hi All

Please mods don't delete.

Just wanted to acknowledge the expertise in this MD forum. I have been reading for many years now, I find it difficult to understand the charts so rely heavily on others.

I respect so many of you with your knowledge and it makes reading this forum very interesting and in winter very compelling. I appreciate that at times it gets very heated in here but my advice to others is that I know now who I want to read and who to skip over, this makes the read a lot easier.

I know this isn't model discussion as such but I know over the past few days it has been a testing time. But, please believe everyone, that for total amateurs such as myself it is fascinating.

Just felt it needed saying.

Cheers

P.S. I believe that winter will bite us back! and looking at the charts to my very inexperienced eye, something is brewing!

[Jason M]

:lol: Well, some cheeky upgrades tonight.

Para ensembles are interesting tonight. Lots of evolving easterlies, and some of the opps are non too shabby either!

I'll wait until the morning i think before getting too interested as what the 12z giveth, the 00z runs often taketh away :lol:

The thing in our favour this time though is that were looking at charts 5/6/7 days away and not 10 / 15 days away.

Jason

[bluearmy]

There is more to it than meets the eye, check my post

funny that matty - i was just looking through them and was contrasting my thoughts with those from this time yesterday. i wasnt at all surprised to see the 00z op run having looked through the stamps T144/T168. yet this evening, i am more bullish re the cold. yes, there are 5 clusters by T168 but cluster 5 is as good as cluster 1 which is the op and control. that is nearly half the ens in the right camp for cold. my mean expectation for what follows T168 would be for heights to extend across through scandi with a large euro trough. given what the ens mean heights for T240 show, stewarts 'ramp' the other evening of siberian heights extending west through scandi towards iceland may not be too far from where tomorrows output might be trending.

Edited January 15, 2012 by bluearmy

[nick sussex]

A very kind soul from net weather sent me this link which is superb regarding the ECM ensembles, and spread of solutions, this incorporates standard deviations, although we get to see the spreads on meteociel this is another way of viewing them:

http://www.ecmwf.int/products/forecasts/d/charts/medium/eps/ensm/essential!MSLP!Europe!168!pop!od!enfo!plot_ensm_essential!2012011512!!/

What we can actually see is the behaviour of the ECM ensembles over a 30 day period by looking at the normalized standard deviation.

Again a big thanks to that kind soul.

[damianslaw]

Reliable timeframe at present as ever is firmly 120 hours and at last we have cross model agreement in this timeframe. All models agree after a milder interlude mid week the trough will dig SE across the country by Friday bringing colder air again from the north.

What happens next is the big question, ECM still sticking to its cold easterly evolution - it has shown this set up for about a week now. GFS on the other hand continues to keep a stronger PV in situ to the east of greenland and isn't keen on advection of azores high NW, however, longer term it is showing pressure heights to our NE exerting a strong influence and a signal for the PV to weaken considerably and move westwards- this is a pattern it has toyed with on a number of runs for late January so those bemoaning GFS at present for the lack of anything cold on the horizon should take note of this development. UKMO is a half way house between ECM and GFS, yesterday it was siding with ECM, but it now suggests perhaps a cold northerly blast next weekend but this being toppled by the atlantic again at the start of the following week - the met office update would support this evolution.

My own view has been for mid atlantic heights to develop strongly later next week these ridging north towards Greenland but quite far enough thus a shortwave will scupper chances of a sustained northerly assault, however, during the last week of January with a NW-SE tracking jet - we will see a well established trough dig deep into central europe, once this moves through with a weakened PV advancing westwards watch those mid atlantic heights finally surging north into greenland whilst at the same time those strong heights over NW Russia sink SE, both features joining this delivering the northern blocking and easterly the ECM has been toying around with for a number of days but it will be the very end of the month before this happens.

[Glacier Point]

Worth noting that the strong message coming out of all NWP output at the moment is for an opening out of the contours (mean deceleration of the westerly winds) across the North Atlantic as the low heights to the north lift out and pull back west, associated with the upstream wavelengths being seriously altered by that Aleutian ridge. The Azores ridge is going to get a serious yank back west allowing the longwave trough and attendant shortwaves to cut across on a NW-SE axis. If you follow the longwave pattern and the ensconsed 850 values, the only way for this to go is underneath the block.

GFS ensemble mean package suggests a strong building ridge over the top of this block by day 10 and a split flow developing over Europe by day 12 (easterly potential high). Of note, the 00z parallel GEFS came up with a strongly negative NAO and the 12z GEFS ensemble mean has popped in a strong ridge developing south of Greenland at the very end (day 15), but a strong signal at that range.