Model Output Discussion - 26th December - 1st January

[Isolated Frost]

Hope everyone is having a fantastic start to the year!

The ECM took the white wine and provided-

[bluearmy]

Morning all and Happy New Year,

Yes, as stated above, ECM 00z has come up with a very interesting run, although as Nick states, not much support from its ensemble members.

Mind you, GFS ensembles are a bit of a dogs dinner!

http://hw.nwstatic.c.../t850London.png

Regards,

Tom

actually tom the parallel gefs are rather better than yesterdays 00z were. the past couple of days have seen decent hemispheric runs at 06z and 18z, whilst the 00z and 12z have been a bit lacklustre re breaking up the p/v effectively by the final third of the month. i'm only using the normal gefs for reference now although naefs and ao/nao output will still be derived from the normal gefs until 24th when the parallel is due to go 'live'.

as iceberg alluded to earlier, the ecm solution in fi looks a bit progressive - we've seen quite a few ncep ensemble members chuck out this option over the past 48 hours, but usually post T300. ecm op fi is known for its bias towards bigger ridges and deeper troughs than actually verify. i suspect that this is one of those occasions though with the vortex beginning to 'wobble' you never know. would be unusual for us to change pattern ahead of the overall model guidance though. anyway, digging the trough into europ was picked up ahead of time by a few op runs early last week so maybe this evolution is another one that we will be looking at on the models later this week though probably a little adjusted.

[lorenzo]

ECM is either down a rabbit hole or has mice at the machinery, or is suffering from a hangover this morning.

Either way it is very easy on the eye.

Looking at the changes run to run the subtle difference is the modelling of the Russian High in it's shape and the positioning of the Arctic High.

By 240 a very different NH outlook from today.

A pattern change appearing very quickly on the models like some have said the move from the Zonal outlook to a colder outlook would appear suddenly on the models, and on this run you can see just how quickly that happens. Still at this point a trend and more runs needed. I do like where the main PV ends up in 10 days time..

[Duane S.]

Happy new year to everyone and happy new year from the models as well by the looks of things.

ECM oozes potential and whilst it is on the colder side of the ens it has support so it can't be ruled out. Liking the 06z from the GFS this morning as well, much more akin to the ECM than the 00z op..

Edited January 1, 2012 by s4lancia

[shedhead]

Much as last week when ECM went off a cold tangent, I expect it will correct itself across the next run or two. No major changes on GFS today, which to my mind is far more pertinent given it's general consistancy of late, so until it comes onboard with a sucession of improved runs for cold I'll remain sceptical.

[Frosty.]

At last, the moderate strat warming is spelling the end of the mixed but mostly mild zonal spell which has been hitting the uk with wave after wave of unsettled weather since early december. It looks like becoming more anticyclonic from next weekend with increasing risk of frosts. The next five day will continue very unsettled and the week will start colder than recently with some wintry showers, especially across northern uk, then a vigorous depression rushing northeast will bring potentially stormy weather on tuesday, at the very least it will be very wet and windy and as this low shears away eastwards across the north sea, it will drag colder air southeast with the wintry showers risk returning, then gradually drying out by the weekend from the southwest with lighter winds, more sunshine and increasing frost risk. Into FI there is a risk of a Northerly and also a small risk of colder weather from the east.

[bluearmy]

Shed, by the time you see the train coming you'll still be stood there in your trunks !!

The 06z gfs in fi not a million miles from the ecm and preferable imo.

The vortex look like it may well split effectively around mid month. Where will the cold go ??

[Duane S.]

Regarding the pattern change you can't help but feel that if the models have underestimated warming effects on the vortex (and fwiw I don't think they have) that we could be thrust into a colder pattern very quickly indeed. Add to that a bit more amplification upstream, a bit more of a meridional jet, a bit less energy being being spewed out of the states, a bit more energy going into the southern arm of the pfj, any or some of these factors coming into play could abruptly swing the balance in about 7 - 10 days time.

[bluearmy]

Ian, I'm not sure you've looked at the 06z from a NH perspective. If you had I doubt you would have posted that last part. Are you sure that what probably follows is what you expect ??

[Frosty.]

Happy New Year to everyone. This is right at the end of FI, but this is where I think we are headed for the second half of January ; http://www.wetterzen...s/Rtavn3841.png We begin to see the progressive zonality ending as the Russian High begins to assume a more normal winter position with cold air underneath. However the PV remains over Greenland and the NAO is firmly +ve.

It may be a new year but you never change do you Ian, there are some positives in today's model output, the gfs 00z is an upgrade on yesterdays run and the ecm has cold potential in FI but reading your posts, you would never imagine that cold weather could be a possiblity.

[johnholmes]

Having a closer look at how the 500mb anomaly charts have slowly altered over the past week and the NOAA version has quite definitely pushed the +ve area of heights further north. Its hard to see what effect, if any, as their chart has little detail much further east, but the idea which the 500mb ECMWF version shows this morning looks to be along the same lines. It is rather more down the line of changing the wavelength pattern than NOAA shows but overall the idea is there os some kind of pattern change emerging 10-15 days further down. I suspect it will be a surface high close to the west or SW of the UK with the main cold plunge, in that period, further east=yippee for my skiing in Wengen!

That is IF it verifies.

A Very Happy New Year everyone-may the weather in 2012 bring everyone some of the weather they enjoy-don't be greedy for one type only.

Edited January 1, 2012 by johnholmes

[Frosty.]

PV remains over Greenland and the NAO is firmly +ve.

I think the PV will split, the models are looking progressively more wintry in the medium range and even the week ahead looks colder than recently with some wintry showers (stormy and less cold tuesday) the ecm 00z prolongs the risk of cold, showery weather for the east until friday, today's gfs 00z is a significant upgrade from yesterday, happy new year all.

[shedhead]

Shed, by the time you see the train coming you'll still be stood there in your trunks !!

The 06z gfs in fi not a million miles from the ecm and preferable imo.

The vortex look like it may well split effectively around mid month. Where will the cold go ??

Shed, by the time you see the train coming you'll still be stood there in your trunks !!

The 06z gfs in fi not a million miles from the ecm and preferable imo.

The vortex look like it may well split effectively around mid month. Where will the cold go ??

Depends what train you are talking about BA. If it's the Pinappple Express, I think it will pretty much keep to schedule across the next week or so, the TGV looks a better prospect but will probably travel southwards too far east, but if you are referring to the TSR it's still broken down in Vladivostock and looks unlikely to get the required parts until February... but even by that time I sincerely doubt I'll be in my trunks!

[The Northern Ramper]

Happy new year all, this is the 4th consecutive gfs run that has showed the vortex splitting on January the 13th in this manner. Yes it is at t300 but yesterday it was t324, surely a trend being picked up on by this model.

[bluearmy]

Depends what train you are talking about BA. If it's the Pinappple Express, I think it will pretty much keep to schedule across the next week or so, the TGV looks a better prospect but will probably travel southwards too far east, but if you are referring to the TSR it's still broken down in Vladivostock and looks unlikely to get the required parts until February... but even by that time I sincerely doubt I'll be in my trunks!

glad you 'picked up the baton' shed and didnt take my post the wrong way. is anyone out there who is qualified to comment on my different take on the end of the 06z op to ian's ???

[phil nw.]

A Happy New Year to everyone from me too.

I have just quickly glanced through the output so far,but it seems that the later frames are showing the vortex under pressure.

We still have some way to go and look likely to remain in this westerly regime for the next 10days at least,but probably more under the influence of the high as we go into week 2.

http://hw.nwstatic.co.uk/gfsimages/gfs.20120101/06/192/h500slp.png

http://hw.nwstatic.co.uk/ecmimages/20120101/00/ecm500.192.png

The troughing into Europe looks well modelled now and will help to keep the high from extending East.

Beyond this evolution the readjustment in the shape of the vortex is still uncertain but it`s looks as if iit`s coming under increasing pressure from recent warmings and mid-month still looks to be the time when the pattern will evolve into something different.

[Tim Bland]

GFS op finaly now in line with ensembles. Lots of support for a cold spell around mid month!

[shedhead]

glad you 'picked up the baton' shed and didnt take my post the wrong way. is anyone out there who is qualified to comment on my different take on the end of the 06z op to ian's ???

As phil has just said and I'll directly quote here.... 'mid-month still looks to be the time when the pattern will evolve into something different'

I don't think there are many on here who would argue with this line, it's looking about as inevitable as anything does with weather in the 10 day+ timeframe, the only real question now

is what effect will the changes have on the weather across this little island.

Of course it's easy to assume that as a change is coming that change will be a profound and radical one towards cold, but it might just as easily be a small, subtle one to something drier

and more settled. One thing is certain, nature always balances itself out, but it never does so across set timescales. I think the most likely senario to emerge through week two is rising

pressure, with the main centre being to the SW, very much as indicated in the GFS FI and allued to by Ian. January should end up being a good deal drier in the west, where many desperately

need a break from incessant rain, but later in the month I still feel we'll get HP building in the right places to give us a proper shot at some wintry weather. As ever tho, time will tell.

Edited January 1, 2012 by shedhead

[J10]

A new thread for a new year.

http://forum.netweat...st-7th-january/