Model Output General Discussion

[Southender]

Well. Thanks very much to the new GFS. May you continue to churn out runs like that. Much colder and more snow for all.

FI - Max of 1c on xmas eve, then up to 12c by xmas day. Don't think so...

:o

Edited December 15, 2009 by LeighShrimper

[Geordiesnow]

Much better run. The only negative would be the low to the north between Iceland and Norway this weekend - it moves in a SW'ly direction thus cutting off the northerly flow. ECM is better, has it further east and evetually into Denmark! However, the UK does seem to remain in the cold air.

Yep, it would be alot more ideal if it was heading South just to the east of us to keep the cold air flooding down to us or better still have it on top of us and give parts of Northern UK a proper snowy spell. :o

However this is a very good run and certainly an upgrade in Southern areas regarding the cold weather.

Still have to see what the UKMO/ECM has to offer though but as Nick says, a good start to the evening output.

[Joneseye]

http://www.wetterzentrale.de/pics/Rtavn16217.png - :o ........Yes kold maybe you're right about the extreme bit

The net-weather version shows temps across the midlands northwards at -10C at midday next Tuesday, but let's face it there is a lot of water to go under the bridge before we get that far ahead.

I have been watching the evolution of this run and am baffled by the track of the low pressure to the north of us, which ends up to the North West of Scotland.. I was thinking that it would be more likely to end up to the east of us? Also it fills in quite a lot as it makes it's way down from the Svalbard region, does that seem plausible?

[Eugene]

Low res up to its predictable tricks again i see.

Even if it came off its take ages for the cold temps to fizzle out so christmas day could still be chilly :o

[kold weather]

To be honest if the 12z did come off even if it did break down for the 22-24th we have a real beast of a set-up showing on the 12z GFS, I'd take that run in a heartbeat, certainly would be up there with some of the more memorable December cold spells IF it came off.

Of course, chances of it being that severe are rather on the low side but the chances are still there.

For now, I'm just interested in the next 72hrs until the northerly airflow, then after that we can look ahead...but theres plenty to look at before then!

[Snowyowl9]

So this is the new parrallel run is it a much different run to the 6z which I would much rather see come off with very s-ly tracking jet and battleground snow easterlies like ECM 0z also.

Whatever we do have a cold low over us and it`s being to progressive late on with shifting the GH too quick.

http://91.121.93.17/pics/Rtavn1441.png

So ice days are shown again.

http://91.121.93.17/pics/Rtavn14417.png

[karyo]

Outstanding 12z gfs but I also think it has overdone the coldness!

We need to see whether the UKMO agrees. By the way, is the meteociel site down?

Karyo

[Mark Bayley]

Outstanding 12z gfs but I also think it has overdone the coldness!

We need to see whether the UKMO agrees. By the way, is the meteociel site down?

Karyo

Not working for me, not the best charts in the world for the UKMO but its a decent enough site till net-weather updates

http://www.wetterzentrale.de/topkarten/fsukmeur.html

[johnholmes]

Alert out for snow etc-see Front Page

[Yeti]

144 is an amazing chart - an ice day almost everywhere with blizzard conditions in the Midlands and South and Arctic sunshine with sub-5 maxima further N:

http://www.wetterzentrale.de/pics/Rtavn14417.png

http://www.wetterzentrale.de/pics/Rtavn1442.png

http://www.wetterzentrale.de/pics/Rtavn1444.png

http://www.wetterzentrale.de/pics/Rtavn1443.png

[Thundery wintry showers]

Looking over the GFS 12Z run, the synoptics look fairly plausible and similar to UKMO/ECM, though I'm not so sure about that low to the N wandering westwards to the extent that it does- the UKMO/ECM scenario of it staying "in situ" is more likely.

However I think NOAA will need to tone down those temperature projections. Yes, the synoptics support a very cold spell, but nothing like as cold as what the GFS temperature charts show. (And I must say I see that as a good thing- I would find a prolonged spell of maxima of -2 to -5C and minima of -10 to -12C a little too extreme- maxima around freezing and minima around -6 would be more realistic, and also more to my liking).

[kold weather]

What the GFS shows is a full fledged cyclonic northerly and what can happen. I have to admit that does look rather OTT but in such a set-up you can get secondary depressions develop as well as other features like fronts and troughs rotating around the circulation so snowfall amounts can be very impressive.

I'm personally happy with the upgrade for Wednesday-Friday though for now, this run seems to be picking up far more precip then the GFS 06z run did.

[Nights King]

alert out for snow etc-see Front Page

The Alert covers the whole of the south i wonder if the south should be split into two halves because that alert obviously doesnt cover somerset/bristol and further west area does it?

[karyo]

Not working for me, not the best charts in the world for the UKMO but its a decent enough site till net-weather updates

http://www.wetterzentrale.de/topkarten/fsukmeur.html

Thanks Mark.

The 144 hours UKMO looks fine at 96 and 120 hours with a north/northwesterly blast but is different to the GFS at the same time: http://www.wetterzentrale.de/topkarten/fsukmeur.html

A potential breakdown to the cold there although it looks quite a fast evolution from the 120 hours chart! Too keen to bring the low presure in from the southwest?

Karyo

[Neilsouth]

Alert out for snow etc-see Front Page

As the cold air advects east through late Wednesday and Thursday precipitation will turn readily to snow, firstly over high ground but fairly readily on low ground. Coastal areas may get just a slight slushy cover. Inland totals of 2-5cm are expected on low ground, in some places,with amounts of 10cm possibly more for the eastern hill slopes. This band of snow will clear away during Friday.

As the winds pick up from an easterly point then some drifting of the lying snow is going to occur on the higher ground especially.

1. The cold air is advecting West from the east , not advecting east.

2. Coastal areas are just as likely to get a proper covering , how far inland does the coastal area cover?

3. In this situation 2-5cm on low ground is too low

4. South east england is NOT southern england , it's south east england.

Can you change those , thanks

Edited December 15, 2009 by neilsouth

[SMU]

http://www.wetterzentrale.de/pics/Rukm1441.gif

UKMO similar to the 06Z Gfs-- poor

Oh well I will stick with the 12z GFS & ECM...

S

[Neilsouth]

http://www.wetterzentrale.de/pics/Rukm1441.gif

UKMO similar to the 06Z Gfs-- poor

Oh well I will stick with the 12z GFS & ECM...

S

Ukmo has been non consitant lately even in the reliable time frame , this goes with the forecasts mention of "some wintry showers" to "weather watch of heavy snow" in just two days worth of runs!

[Snow Queen one]

http://www.wetterzentrale.de/pics/Rukm1441.gif

UKMO similar to the 06Z Gfs-- poor

Oh well I will stick with the 12z GFS & ECM...

S

It doesn't work like that does it though Steve. Which one is right i wonder.lol

[Cecil Hogmanay Melchett]

That ukmo run is just bizarre between 120 and 144h.

One things for sure with that run,it will be all over by monday,its just incredible,we get a stunner and then ukmo comes up with THAT

[snowmadchrisuk]

It doesn't work like that does it though Steve. Which one is right i wonder.lol

IMO UKMO breaks through that block way to quickly , I will be interested to see what the short term 850's are when they become available later.

[Buzzit]

Hi All, Just theorising...

It would be a coup for the new op GFS if it has nailed it out to Saturday

Would certainly cause a few issues for UKMO & ECM funders if the ECM

was also to side with the latest UKMO...

However Im only about 50% positive on the details of the run past Friday

UKMO seems a bit safe during the same period... (if that is the right expression)

in any case I would hate to be having to make a decision at the METO

about how to call it now... all eyes towards tonights fax charts me think

[moses]

People are banging on about the possible snow on Monday but thats still F.I yet.

Look a bit closer to now... Thursday evening...

Mmmm.......... What I find disconcerting is the models are showing one thing and people like The Met Office/ John Holmes on Net Weather video forecasting rain with a wintry mix. Surely not?

[Geordiesnow]

http://www.wetterzentrale.de/pics/Rukm1441.gif

UKMO similar to the 06Z Gfs-- poor

Oh well I will stick with the 12z GFS & ECM...

S

Still looks pretty cold for Scotland though.

And why are you ignoring what the UKMO saying for? Is it because it is showing what you don't want to see and that is a chance of an breakdown via the Atlantic.

The GFS is better than the UKMO but you can hardly say the UKMO is poor though when you have cold weather for roughly about 144 hours can you? And for some quite alot snow in that time and i can bet people in Northern and eastern Scotland in particular would certainly disagree with you regarding this run being poor.

Anyways, what the chances of both the GFS and UKMO being accurate at that range? Very small but it's about trends and the trend i do see that a breakdown via the Atlantic is likely going by all the output but when, will be the question? Most output has the breakdown at around the 22nd December although some go for a few days after that.

enjoy the cold and snow coming up(and you should certainly see snow Steve) and worry about breakdowns when we get more agreement.

[Thundery wintry showers]

UKMO had a wobble a while ago when it brought low pressure in from the SW for around today at T+144. It's only worth taking note of, IMHO, if the ECMWF trends towards that solution, as the low does seem to take an "about turn" rather too quickly. The initial northerly is more similar to GFS 12Z than the 06Z which makes the fast breakdown all the more suspect.

[bluearmy]

i dont think the remainder of the 12z's will sort out beyond T96, even if they all side against GFS 12z. too much run to run inconsistancy regarding how far south the low punches and its interaction with the troughing from the southwest. GFS 12z had a different jet orientation (very se like last nights 18z)