Model Output Discussion

[Don]

Well here we are again before December has even begun, and already the ramping is well underway! The ECM has certainly reduced people's inhibitions in that respect.

And that's the way it should be especially after such an awful November! Charts like these are all part of the Winter fun on here whether they come off or not. I'm not getting excited yet, but these charts are nice to look at all the same.

:unsure:

[nick sussex]

The latest ecm ensembles for the Netherlands are out:

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

The operational run supported by the control run and decent support, the extended ensembles are out later so we'll see whether they go a step forward and bring the easterly in,personally at this moment in time never say never, at some point synoptics that haven't been seen for many winters are bound to make a return, the problem is to get there will take a while and with the amount of rain thats likely to fall beforehand is likely to cause serious issues with flooding.

Overall i'm very dubious of the ecm but everyone knows I'm ultra critical of FI anyway.

[Geordiesnow]

It's amuses me reading this thread, it would seem that if the GFS produces a decent FI for cold fans it gets dismissed stright away yet because the ECM shows decent FI, it does not get dismissed so easily.

How many times has the ECM at the 216-240 hour range showing some lovely northern blocking charts this Autumn? So many times that everytime i see an ECM run, i expect to see some northern blocking of some sort.

I am a bit surprised at the GFS 12Z run, no surprises that the UKMO/ECM is not hinting what the 12Z is showing at this stage. I somehow think it will be a one off run but i suppose you can't rule it out seeing as it's not that far out.

[Yeti]

Not what I would call an outlier. It's just about the coldest member for about 24 hours at one point in the run, but never an outlier. Other members are too close to it for it to be classed as such.

Anyway, the ensembles are liable to change dramatically when it suits them, as I found out on many occasion last winter.

Sorry, it was the Aberdeenshire plot I saw first before I changed the name in the URL:

http://charts.netweather.tv/ensimages/ens.20091130/12/t850Aberdeenshire.png

Anyway true, last year they were all over the place.

It's interesting going from this:

http://www.wetterzentrale.de/pics/Recmnh1681.gif

to this:

http://www.wetterzentrale.de/pics/Recmnh1921.gif

in just 24 hours, as there are some pretty awesome height rises in the Arctic. There haven't been 552+DAM heights over Svalbard in winter for quite a while, I believe.

[bluearmy]

NOAA discussions seem to feel that the massive block over alaska next week will be a rex block so may well be there for a while. with this pumping warm air into the other side of the arctic, i think anythings possible in a couple of weeks time which is why i find Ian's posts so frustrating.

maybe Kevin can dig out illustrations of a long lasting large east pacific ridge at this time of the year without there being a strong p/v present and the consequences for NW europe, within the 'modern e*a'. (sorry to TEITS cat)

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

only 60 hours long but impressive nevertheless. of course the way the 12z evolved, the southern half of the uk (and dutch coast) would be subject to the odd influx of warmer air with shortwaves passing to the south. Definitely a cooling trend towards the end of the run.

Edited November 30, 2009 by bluearmy

[weather eater]

Sorry, it was the Aberdeenshire plot I saw first before I changed the name in the URL:

http://charts.netweather.tv/ensimages/ens.20091130/12/t850Aberdeenshire.png

Anyway true, last year they were all over the place.

It's interesting going from this:

http://www.wetterzentrale.de/pics/Recmnh1681.gif

to this:

http://www.wetterzentrale.de/pics/Recmnh1921.gif

in just 24 hours, as there are some pretty awesome height rises in the Arctic. There haven't been 552+DAM heights over Svalbard in winter for quite a while, I believe.

I'm sure some have been seen in FI before and that’s all this is, an FI projection, so its possible that they might not be seen for sometime to come.

[Duane S.]

NOAA discussions seem to feel that the massive block over alaska next week will be a rex block so may well be there for a while. with this pumping warm air into the other side of the arctic, i think anythings possible in a couple of weeks time which is why i find Ian's posts so frustrating.

My point exactly which is why it is so frustrating that my criticisms of just that seem to get removed yet Ian's posts remain there laughing in the face of reason. Then again I suppose it's him that is looking increasingly daft so hey...

The ECM really is a classic and I don't think it is THAT unlikely either. The signs have been there for a while regarding some serious heights building above us so why not? Yes it's FI but a few more runs like that and we will be on to a trend. Where's SM and his thoughts when you need him??

[BLAST FROM THE PAST]

I'm a little surprised at the ECM, there is no plausible reason for the evolution from T168 to T192. One thing is for sure, deep troughing in the mid-Atlantic and I would expect that to be given the boost needed to transfer this energy further East and see a pressure rise over Europe.

Why Ian, that looks the least likely outcome what you describe. Jet is running too far south for your christmas pudding synoptics to take hold and has been for 2-3 years.

Incredible model outputs folks......where are we going?

BFTP

[nick sussex]

Latest verification stats show model reliability now dipping, this often happens during upstream changes. The funniest thing is that over the last day the NOGAPS here shown as FNMOC has edged ahead of the big 3!

http://www.emc.ncep.noaa.gov/gmb/STATS/html/acz6.html

The bridesmaid finally becomes the bride, probably won't last long but at least its had its day in the sun, the gfs has dipped to the bottom.

In terms of the different gfs runs heres the stats upto day 5, surprisingly the gfs 12hrs and 18hrs pub run verify better than the earlier runs, perhaps we'll have to rename the gfs 00hrs and 06hrs the hangover runs! a bit lame but it was the best quip i could think of!

http://www.emc.ncep.noaa.gov/gmb/STATS/html4x/acz5.html

Although i've been very critical of the gfs i much prefer its 12hrs run as a want preference, at least its quicker and there won't be so much wind and rain beforehand, and next week i've got friends over and judging by the ecm we won't even make it upto the mountains unless we've got a snowplough handy, so for once gfs please be right! :unsure:

[Thundery wintry showers]

I'm not sure, I think the jet is "predisposed" to track a little too far south at the moment for Ian Brown's prediction to be particularly likely- though I think it's more likely than those fantasy easterly scenarios as far as the near term is concerned. I am expecting a southerly type for most of the first half of December with some blocking to the north and east but frequent low pressure to the west and south bringing a generally wet, southerly-dominated regime, which will tend to be mild especially by night. Think of the pattern during the first half of December 2000, but not quite as mild as that. I think we will see a rise in temperatures for a time in the second week as the greater energy in the jet provides deeper depressions, and the greater W-E impetus may mean the south ends up much milder relative to normal than the north.

If anything I think the blocking to the N/NE is the more likely to come into play later in the month as per Glacier Point's suggestions, but I am expecting a mild December nonetheless.

Edited November 30, 2009 by Thundery wintry showers

[kold weather]

This is a very hard call to make and I think confidence has to be very low simply because the difference between a very mild southerly and a possibly very cold SE/E airflow is very minimal indeed. The best news though IMO is the slant the jet stream has right now, it really is NW-SE thanks to what appears to be a weaker then normal PV and developing block in the Pacific and this is very important...it means even if this particular stab it at doesn't occur it wouldn't take much to shift things to a colder gear, all it would need is a slidder low and pressure rises to the north and we get into very interesting synoptics. The GFS has this and to some extent so does the ECM, though it is slower and more bullish with the low.

Expect a lot of higher pressure to the north though probably not 'real' upper highs but rather highs being there thanks to a very depressed jet streak...lets just say these were a pretty common factor in the 60s...however as has been mentioned this could yet evolve into a pattern where we are close but not quite...remains to be seen.

[Rob]

loving the latest charts, but i'm half expecting the gfs to be completely different next run!

[kold weather]

I'm not sure, I think the jet is "predisposed" to track a little too far south at the moment for Ian Brown's prediction to be particularly likely- though I think it's more likely than those fantasy easterly scenarios as far as the near term is concerned. I am expecting a southerly type for most of the first half of December with some blocking to the north and east but frequent low pressure to the west and south bringing a generally wet, southerly-dominated regime, which will tend to be mild especially by night. Think of the pattern during the first half of December 2000, but not quite as mild as that. I think we will see a rise in temperatures for a time in the second week as the greater energy in the jet provides deeper depressions, and the greater W-E impetus may mean the south ends up much milder relative to normal than the north.

Its very hard to say as the difference really isn't all that great between a cold SE flow and as you say a southerly type flow. If I was to make a punt I'd probably suspect we will see a bit of both over the next 2-3 weeks however it is interesting to me seeing these slidders, one of these is surely going to dig far enough south to allow a ridge of high pressure to develop to its north and give us cold. whether or not this will be the one though remians to be seen.

[cooling climate]

Perhaps the models are picking up on the stratospheric influence. Look at the GFS and ECM split PV at 10 days. Where would I put pressure rises looking at these? Hmmm.

c

Yes this is what I was alluding to in a post earlier with a segment of the vortex left over

in Russia and the rest migrating to Canada (Hudson bay area).

If this happens then game on I think.

[bluearmy]

http://www.meteociel.fr/modeles/naefs_cartes.php?ech=192&code=0&mode=0&map=1

http://www.meteociel.fr/modeles/naefs_cartes.php?ech=192&code=1&mode=0&map=1

NAEFS not far from an easterly at quite a long range. impressive northern blocking at such a timescale.

not very 'modern e*a' ish type charts for december (whoops - sorry dave's cat again )

[tinybill]

http://www.meteociel...=0&mode=0&map=1

http://www.meteociel...=1&mode=0&map=1

NAEFS not far from an easterly at quite a long range. impressive northern blocking at such a timescale.

not very 'modern e*a' ish type charts for december (whoops - sorry dave's cat again )

with this post im off to bed to dream good things to come!!!

[Glacier Point]

NOAA discussions seem to feel that the massive block over alaska next week will be a rex block so may well be there for a while. with this pumping warm air into the other side of the arctic, i think anythings possible in a couple of weeks time which is why i find Ian's posts so frustrating.

maybe Kevin can dig out illustrations of a long lasting large east pacific ridge at this time of the year without there being a strong p/v present and the consequences for NW europe, within the 'modern e*a'. (sorry to TEITS cat)

http://www.knmi.nl/e...agse/index.html

only 60 hours long but impressive nevertheless. of course the way the 12z evolved, the southern half of the uk (and dutch coast) would be subject to the odd influx of warmer air with shortwaves passing to the south. Definitely a cooling trend towards the end of the run.

CPC do this every night - historical analogues provided for NH pattern:

The composite page is down but judging by those dates, my guess would be for an interesting pattern rolled forward.

[swfc]

Pub run but wow.if only.Northern blocking to dream of.

[cooling climate]

Again the vortex has split nicely allowing the height rises in the Arctic to push south

building heights to our north, and bingo.

Edited November 30, 2009 by cooling climate

[bluearmy]

interesting date analogues provided by cpc then ...............

hopefully within a few weeks, dave's cat will be completely safe as the term could be consigned to the waste bin.

the 18z continues the trend. (parallel not playing though)

Edited November 30, 2009 by bluearmy

[chionomaniac]

Interestingly, the GFS and ECM are not too far away from each other at T+240. Will that still be the case in the morning?

[kold weather]

Pretty amazing blocking from the GFS, very close evolution to the ECM with us taking 2 bites of the cherry (which is more realisitic then the 12z GFS run) but with a strengthening -ve AO and a jet that is already pushing southwards we end up with a synoptically amazing set-up with a big upper ridge connecting the Azores high to a monster Greenland high which stops everything in its tracks.

Very long way to go but to have the ECM and the GFS in good agreement is a bonus.

[The Eagle]

Very good output this evening overall. There is some similarity between the models right out to 192 vaguely supporting the Northern blocking scenario and possibly an Easterly. Very early days though.

[nick sussex]

I suppose whats interesting here is even though the gfs shows some initial differences to the ecm they sort of meet later on, does this mean that theres a very strong signal for this?

The only problem i have is that theres so much rain to get through whilst the uk trough sinks slowly south, can we not just take a short cut to the cold without noah and his ark appearing beforehand!

Over to you GP is there a way round all this rain to get to cold, i've read your earlier post which suggests not but was hoping you'd have something else in your bag of tricks.

Edited November 30, 2009 by nick sussex

[Stu_London]

A bizarre 18z run - with huge northern blocking.

I am not going to be as quick to dismiss this as all of the models have picked up on some northern blocking tonight and the 12z ensembles had some cold runs reappearing again.

evolution will almost certainly be different and we may still end up with the atlantic winning out. there is at the very least a further 12 hours interesting model wathcing however and probably more.