Model Output Discussion

[Thundery wintry showers]

Ah, I see the problem- the shortwave ends up too far east and largely fizzles out so we end up with a build of high pressure from the north. Note- in sharp contrast with the 06Z run (and yesterday's GFS 12Z) so the models are really having headaches over the behaviour of this shortwave. Kold Weather's earlier posts seemed to be concerned more about the shortwave blowing up over the north, rather than fizzling out way out in the North Sea! For cold/snow lovers I suggest that it needs to be a bit further west than on the GFS 12Z but further east than on the 06Z (or in other words where it was on yesterday's 12Z runs).

[Lewis]

Uh, oh looks like the cold air may miss us, still time for rest of the run.

After looking at all the charts, dews, 850's, wind barbs etc i think this run is not the best, although it's still better than a SW wind with heavy rain. What reef said above worries me, and said the word "Initial" i think at the moment in time the models are all showing the re-load east of us, so it's not looking great.

Fingers crossed though, things do and most probably will change, let's hope its for the best.

Lewis

[kold weather]

We get VERY lucky in FI, a new high forms over the UK but the Greenland high is just strong enough to shunt the PV southwards again and drags us back into the Arctic air, howveer this run is *not* a good trend at all because we really are on the cusp of losing it all...

ECM looks like it may have found a new trend on its 0z run based on this GFS run but more runs are needed first.

TWS, that shortwave is going to cause the models a nightmare, the 12z though is ok but we do get a huge slice of luck IMO.

Edited December 10, 2009 by kold weather

[MKN]

Ok so we dont hit the coldest pool of air only -5s, but because of that we then get another shot at it later on. looks like a good solution if anyones hoping for a white christmas.

[Methuselah]

I think, it just goes to show that, trying to predict more than 7 days' ahead is a - waste of time??

[Eugene]

Wetterzentrale is down so here's one FI chart from meteociel, looks like harsh frosts to me

http://91.121.94.83/modeles/gfs/run/gfs-0-300.png?12

[kold weather]

Yep Eugene, the 12z is indeed a cold run but we get there through some very dodgy synoptics indeed, if we didn't get that weak shortwave develop from our east I suspect we'd have had a very poor FI indeed, probably one with the Azores high showing its hand.

However I will also say the 12z is almost certainly imploding that -ve AO way to quick, it always is the most progressive of runs.

FI is good snowmadchrisuk, but as I just said, its a very shakey set-up and one that I'd bet would implode before we got there. However we do see the huge benefit of having a southerly jet, it tips the odds in our favour again...

Edited December 10, 2009 by kold weather

[Geordiesnow]

You can't really be too concerned about this run as we won't know until the 12Z ECM if it's a possible trend or not.

Anyways, still alot of potential on this run but we all know that the line between success and failure.

[Iceberg]

I think we just have to accept that beyond 96Z a variety of things could happen beyond 168Z, you could pick any cold scenario you wanted and it would probably be shown by a run at some point. However the likelyhood of cold continuing seems to be growing, snow will happen at various places at somepoint and Monday/Tuesday is a bl00dy good start !.

[mountain shadow]

The models still don't have a handle on that Low Pressure system moving down through Scandi next week.

1 How far east or west will it be?

2. How deep will it be

3. How far south will it get.

All to be decided, I guess FI is what t+72 at the minute comparing this run with the 0z ECM.

If this run does verify, it would be a proper winter spell with double figure temps a memory.

[Eugene]

Keeps it very cold until at least boxing day :blush:....LP pushing north at the very end but WAY too far away to worry about at this stage, abit like getting excited over a cold spell starting dec 27th

[kold weather]

You can't really be too concerned about this run as we won't know until the 12Z ECM if it's a possible trend or not.

Anyways, still alot of potential on this run but we all know that the line between success and failure.

Yep we sure do, we come as close as its possible to go without failing on this run, one misplaced shortwave from the Atlantic LP will ruin it all on that FI, its amazingly shakey...but it would be very cold if it came off.

Also, that easterly looks very good, I'm betting showers are quite a lot more widespread then the GFS is predicting, esp down the usual streamer routes in a ENE/E flow.

[Methuselah]

I think we just have to accept that beyond 96Z a variety of things could happen beyond 168Z, you could pick any cold scenario you wanted and it would probably be shown by a run at some point. However the likelyhood of cold continuing seems to be growing, snow will happen at various places at somepoint and Monday/Tuesday is a bl00dy good start !.

I do suspect that that is all anyone can really say, Ice...

[Iceberg]

The GFS Alternative is a belter of a run, very snow Thur/Fri/Sat etc next week, keeps the SW further west and runs it west, without the mild end.

BTW it also keeps the snow Mon/Tues but to a lesser extent.

[Mark Bayley]

The GFS Alternative is a belter of a run, very snow Thur/Fri/Sat etc next week, keeps the SW further west and runs it west, without the mild end.

BTW it also keeps the snow Mon/Tues but to a lesser extent.

Was about to mention that! The parallel is very good and shows one of many different outcomes. The op run isn't to bad and many would still see snow from it. We are going to see different setups being shown over the next few days. UKMO on its way out now, hopefully good !

[TEITS]

Apologies for asking but i've only just got in. Im struggling to view any charts at the moment even the Meteociel are very slow. Anyone else having problems viewing the 12Z GFS.

By the way I have seen parts of the GFS Parallel and it looks a belting run.

Edited December 10, 2009 by THE EYE IN THE SKY

[mountain shadow]

The new GFS Parellel run has been very consistent in bringing the cold quicker and retaining it. Not sure how it's verifying compared to the GFS Ops but looks promising.

[stewfox]

With that 528 dam in on Sunday , the Current forecast would be Showers turning increasingly wintry with a covering likely over night for inland areas East of Birmingham.

Yes good summary

The 'colder air' appears to be arriving a bit quicker then suggested yesterday

A sunday night 4am lamp post watching

[kold weather]

A totally different evolution on the 12z Paralell run, this time we keep the shortwave and the whole flow backs westwards forcing the upper high over Greenland to sink SW instead of SE, ends up with a similar FI though to be jonest and breakdown in time for xmas day itself on that run.

Still at least it pretty much a surefire snow event from it.

[snowking]

The new GFS Parellel run has been very consistent in bringing the cold quicker and retaining it. Not sure how it's verifying compared to the GFS Ops but looks promising.

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

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

Pretty similarly on the last few runs to most of the major players at day 5 and 6, but overall for the month not as good as the others - though it is noticeable the last few days especially the increase in verification

I'd imagine this is to do with them getting ready to launch it as the operational imminently, so its probably now running at full capacity

SK

[Iceberg]

Everywhere is having severe Chart problems due to overload it would seem, METO has now crashed on the french site, but it did look more GFS like at 72hrs.

Netweather is doing fine, but no diss to NETW, NETW does not update as quickly nor have the GFS alternative (Sorry Paul)

[Guest North Sea Snow Convection]

Its ok having more showers, but the question is. Will they fall of snow? I don't think so tbh.

Especially for coastal areas in the SE and NE.

If the GFS output verifies then the showers around the SE coastal areas around the overnight Mon/Tues period would definitely be snow. Very similar previous scenarios from time i lived there alwayshave produced snow in that region - sometimes quite significantly in fact.

Taking the GFS 12z as a whole I don't think you ask any more. I think the fact that the AO is going so staggeringly negative is going to mean that pressure will constantly be pushing down from the north so the 12z GFS is quite plausiblee imo in building a renewed very cold ridge. This is a set-up that looks like it could be very hard to break down.

As always suspected - it looks as though getting stable and (intense) northern blocking in the main winter months is still perfectly possible these days - and how!!

[shuggee]

Apologies for asking but i've only just got in. Im struggling to view any charts at the moment even the Meteociel are very slow. Anyone else having problems viewing the 12Z GFS.

No problems here Dave

http://www.netweather.tv/index.cgi?action=nwdc;sess=

[Tucco]

Meto

Mark

Teesdale,Co Durham

Edited December 10, 2009 by Tucco

[Neilsouth]

http://91.121.94.83/modeles/gfs/run/gfs-0-348.png?12

http://91.121.94.83/modeles/gfs/run/gfs-1-348.png?12

http://91.121.94.83/modeles/gfs/run/gfs-1-360.png?12

http://91.121.94.83/modeles/gfs/run/gfs-0-360.png?12

Xmas