Model Thread - 14th Jan - Mk2

[nick sussex]

The ECM ensemble maps still show a large spread of solutions at 168hrs:

http://www.ecmwf.int...t!2009112700!!/

I had to laugh this morning at the preliminary NOAA mornings discussions, I think the forecaster had a late night and couldn't be bothered to write much.

The whole discussion reads as follows:

USED THE 00Z/15 ECMWF FOR THE PRELIMINARY FRONTS AND PRESSURES FOR

DAYS 3 THROUGH 7.

[bluearmy]

just to illustrate how notable the parallel is for the end of jan

the T384 forecast for now (from 2 weeks ago) / the current gefs forecast for end jan / the current parallel forecast for end jan

infact naefs deep fi (using normal gefs) now showing a very similar pattern to fridays cpc 8/14 dayer. positive anomoly newfoundland stretching through greenland to svaalbard and beyond. if they were using parallel gefs, would be even more impressive.

[kev238]

I think what doesn't help on this thread is when people repeatedly state gfs verifies fourth in stats. Sometimes it does, equally it is top sometimes, generally around 2nd or 3rd; the verification graphs show great variability with ECM generally ahead but not always.

As for gfs winning this battle, it is far too early to say. On the face of it you would say ECM has moved more towards the gfs than vice versa but 144hrs is still quite a way out.

For me, my first port of call is always the met office 6-15 and 16-30 day forecast; their forecasts have been spot on, and have barely mentioned snow in their updates at all this winter; that is a fairly clear signal, thus far, that mouthing majorly cold is expected by them. Therefore, cold charts are treated a little bit sceptically this winter by me, whereas last year, I was a lot more positive about snow chances!

[Frosty.]

I had to laugh this morning at the preliminary NOAA mornings discussions, I think the forecaster had a late night and couldn't be bothered to write much. The whole discussion reads as follows: USED THE 00Z/15 ECMWF FOR THE PRELIMINARY FRONTS AND PRESSURES FOR DAYS 3 THROUGH 7.

I bet they had a laugh when they saw the gfs op run.

[chionomaniac]

It's worth pointing out as the latest GFS comes out that FI starts at T+96.

And if possible try and look at the hemispheric model to get a bigger picture.

[cooling climate]

As far as a modeled cold spell goes rather than synoptic irregularities between

the models it is looking as though the continued climbdown from the ECM is

virtually complete,kudos to the GFS then.

ON A MORE SERIOUS NOTE WHEN A MODERATOR CALLS ONE OF ITS MEMBERS BORING AND DELETES HIS POST IT IS NOTHING SHORT OF DISGRACEFUL AND THAT MOD SHOULD BE

BANNED.I BROWN IN HIS DEFENCE LOOKS THIS MORNING TO HAVE BEEN CORRECT IN HIS

ANALYSIS. I SEE THEIR HAS NOT BEEN AN APOLOGY TO HIM ON THIS THREAD AND THAT

HE HAS NOT YET MADE A POST THIS MORNING.

THE MOD IN QUESTION IS A SARCASTIC SILLY LITTLE TOAD AND SHOULD BE RID OF.

[k19]

Interestingly the GFS modelled low pressure off Newfoundland at T144 has weakened significantly from the 00z.

[TEITS]

06Z NOGAPS continues with the trend.

Having said this im still unhappy with the disagreement between +96/+144. The key points for me are:

1. How far SE will the trough dig.

2.How far E will the next LP be around the Greenland/Iceland area. Will this be further W than the GFS is suggesting.

3. Uncertain with regards to the ridge from the Azores HP. Will we see greater amplification than the GFS is suggesting stalling the next LP I mention above.

So at the moment im back on the fence!

[BLAST FROM THE PAST]

It's worth pointing out as the latest GFS comes out that FI starts at T+96.

And if possible try and look at the hemispheric model to get a bigger picture.

Agreed 100%.

Also looking at the UKMO and ECM 144. What the ECM goes on to do 168 to 192 does not look at all right to me. It moves the centre of that LP SW and strengthens is hence we lose that 'favourable motion' and we see no westward advancement of the block to our NE.

BFTP

[Nick F]

It's worth pointing out as the latest GFS comes out that FI starts at T+96.

And if possible try and look at the hemispheric model to get a bigger picture.

Sorry Chino, could you explain why you think FI starts at t+96? The GFS operational continues (and a good majority of the ens recently) to go for a cold northwesterly flow next weekend, and ECM op this morning seems to be headed in that direction now too. Though UKMO this morning maybe giving you this uncertainty beyond this timeframe?

Cheers, Nick

[SMU]

I would urge people to review the 12's & then the 00z-

this is certainly not conctrete the GFS 06Z V 00z its a mile apart- although it is more amplified at 120 & is 'seeing' some sort of +VE pressure build over Scandi-

A very difficult situation to model, especially when we have been some zonal for so long-

We still have the ridging into Greenland to resolve & also the 120-168 timeline in terms of how that newfoundland low orientates itself-

Looking at the ECM ensembles today reading between the lines I would say the control is slower at day 8-10 & allows more pressure build to the NE- there is one/ maybe 2 days milder then another shot at an easterly- rather like the 12z ECM yesterday-

lots to discuss- hopefully people will post some charts + links on their analysis today to make to clear for the more inexperienced members viewing -

Lets see what the PM runs bring after the irrelvent 06z...

SYLVIAN IF YOU ARE READING SORT YOUR NOGAPS NORTHERN HEMISPHERE LINK OUT ON METEOCIEL THE HYPER LINK IS BROKE

S

[k19]

Very strange pattern of isobars over the uk

Can't understand what is keeping them that far south.

[Cal]

Interestingly the GFS modelled low pressure off Newfoundland at T144 has weakened significantly from the 00z.

Also the Artic high is much more prominant on this run with a more amplified mid atlantic ridge, subtle change here from the GFS

[chionomaniac]

Sorry Chino, could you explain why you think FI starts at t+96? The GFS operational continues and a good majority of the ens recently have been going for a cold northwesterly flow next weekend, and ECM op this morning seems to be headed in that direction now too. Though UKMO this morning maybe giving you this uncertainty beyond this timeframe?

Cheers, Nick

I guess I am looking more hemispherically Nick - at the bigger picture - and I am not saying that at T+96 we will have a switch on our hands but changes here will have bigger changes later on.

Already the modelling of the Eastern Siberian ridge is completely different at T+120. It is far stronger. This then in turn reduces the strength of the cross polar shortwave flow that was reinforcing the Canadian vortex. At the same time there is less energy in the area north of Greenland and there is a completely different profile entering Scandinavia.

Do these ensembles look reliable from day 4?

c

[shedhead]

It's worth pointing out as the latest GFS comes out that FI starts at T+96.

And if possible try and look at the hemispheric model to get a bigger picture.

Why does FI start at T+96hrs? All the main models look in pretty decent agreement at 144hrs, simply showing rather subtle variations on a general WNW flow theme, indeed things look very much

more solid at that timeframe than they did only 24hrs ago.

EDIT: Just seen your reply to someone else who asked much the same question.

[kold weather]

ECM now very much come into line with the GFS with a far flatter pattern, fair play to the GFS. That is not to preclude any colder shots still from variations of cool zonality, for example both the GFS/ECM are still fairly cool for the north.

Still not a hint of anything more than a little below average on the models this morning sadly...UKMO is best but even that is not being as agressive now.IOndeed 06z GFS is back to very mild by 168hrs!

Pattern isn't too poor for the north, but pretty shocking for the south now.

[Cloud 10]

Quite a difference between yesterday's 06z gfs and today's regarding the end of the week,looks to be

lining up with the ecm and ukmo.

yesterday> today>

[nick sussex]

More nonsense from the GFS with yet another change in the NH pattern.

Just looking at Europe may seem that its been consistent but its all over the place. Fair do's if people want to criticize the ECM but regardless of its changes near the UK its been much more consistent in the overall NH pattern.

[Zakos]

Why does FI start at T+96hrs? All the main models look in pretty decent agreement at 144hrs, simply showing rather subtle variations on a general WNW flow theme, indeed things look very much

more solid at that timeframe than they did only 24hrs ago.

look how much stronger the arctic high is. It doesnt matter if we experience exactly the same weather at that time, what occurs a few days after 96hours all depends on how much influence the arctic high will have. Until it modelled correctly there is no telling what could happen, therefore hemispherically 96 hours or so is FI

[kold weather]

Cloud 10, the GFS may have slightly moved towards the ECM, but make no mistake, the ECM has nearly done a 180 on its old solution, there has been only one winner in this battle and thats the GFS.

Anyway I wouldn't get too downhearted about the models, I'd not be all that susprtised to see the models toy with this idea again in another 5-10 days time, still quite a wide range of solutions on the table down the line as well.

[Nick F]

I guess I am looking more hemispherically Nick - at the bigger picture - and I am not saying that at T+96 we will have a switch on our hands but changes here will have bigger changes later on.

Already the modelling of the Eastern Siberian ridge is completely different at T+120. It is far stronger. This then in turn reduces the strength of the cross polar shortwave flow that was reinforcing the Canadian vortex. At the same time there is less energy in the area north of Greenland and there is a completely different profile entering Scandinavia.

Do these ensembles look reliable from day 4?

c

Cheers Chino, wasn't a gripe or anything, just don't always have the time these days to analyse the bigger picture!

The positioning of cold pooling in higher latitudes certainly looks less stable and more volatile than recently - especially towards Greenland, so we could see quite a bit of twisting and turning by the models over the coming days, as they get to grips with where these cold pools/vortices move.

Though despite what some think, the GFS ops and ens IMO seem to have been fairly stable over last few days with it's modelling for this part of the world up to the end of next weekend, i.e. a cold northwesterly flow developing by the end of the week.

[kold weather]

More nonsense from the GFS with yet another change in the NH pattern.

Just looking at Europe may seem that its been consistent but its all over the place. Fair do's if people want to criticize the ECM but regardless of its changes near the UK its been much more consistent in the overall NH pattern.

Maybe true but the GFS has been WAY better thus far on the Atlantic side, which at the end of the day is the key area for our weather, the ECM WAY overdid the blocking and now its almost got none at all which the GFS has been showing for a while now. The GFS may have been very topsy turvy with some aspects, but its nailed the Atlantic aspect of this set-up, and that is the key area for our weather really, especially when we have a reasonable PV still.

[nick sussex]

BREAKING NEWS FROM OUR CORRESPONDENT IN THE USA!This just in from NOAA.

USED THE 00Z/15 ECMWF FOR THE PRELIMINARY FRONTS AND PRESSURES FOR

DAYS 3 THROUGH 7. THE ECMWF IS BEST CORRELATED WITH THE GEFS MEAN

AT THE MEDIUM RANGE...WITH THE OTHER DETERMINISTIC

MODELS...INCLUDING THE GFS...DIFFERING ENOUGH OVER SEVERAL KEY

AREAS OF CENTRAL NORTH AMERICA TO CAST SUSPICION ON THEIR

SOLUTIONS. THE GFS IS A FLAT OUTLIER WITH THE WAVE CROSSING THE

EASTERN GREAT LAKES AT THE START OF THE PERIOD...WITH THE GEM

GLOBAL ALONE IN CONSTRAINING THE POLAR AIR NORTH OF THE CANADIAN

BORDER FOR THE DURATION OF THE FORECAST

[chionomaniac]

Cheers Chino, wasn't a gripe or anything, just don't always have the time these days to analyise the bigger picture!

The positioning of cold pooling in higher latitudes certainly looks less stable and more volatile than recently - especially towards Greenland, so we could see quite a bit of twisting and turning by the models over the coming days, as they get to grips with where these cold pools/vortices move.

With the instability of the polar vortex and shifting sands with every tide it is wise not to get too set on one outcome. The one sand we would like to see shifted remains in situ over Canada!

[TEITS]

Last post from me until later.

I feel its took early to be saying well done to any model at the moment. Look at the 0Z GEFS mean at +120 and there is a difference of 9C showing on the upper temps ranging from +2C to -7C.

http://cdn.nwstatic.co.uk/ensimages/ens.20120115/00/t850Cambridgeshire.png

A simple way of summing up my feelings is this. After last nights 12Zs I was ready to jump off the fence towards cold but this morning i've returned back on the fence. If the 12Z ECM continues with the same output I may be swayed to jumping towards a milder outcome.