Model Output Discussion

[swilliam]

that ridge pushing up from the south is really annoying.very close to a good easterley here :blink:

Very annoying - it sunk our high - but it seems to be showing up on the all runs now including the METO T144

[Lewis]

Im really confused .Why is this run not so good?

Please can someone explain.because it looks okay to me

Depends how you look at it, a slight upgrade for areas looking for heavy snow in the short term, very poor in the long term for people looking for a sustained cold spell with N and E outbreaks, delivering snow to many parts of the U.K, if someone asked me what i wanted, i would take the latter.

Lewis

Edited December 26, 2009 by Storm Force Lewis

[Methuselah]

Guys,

FI is FI - it changes faster than I change my socks! Pay no attention to it...And, it's wrong more often than it's right! :blink:

[Thundery wintry showers]

It all depends on location. This run is a big downgrade for me and I by far prefer the 06z run. If it turns out like this then the SW will be seeing rain and milder temps while we watch the rest of the country get all the snow again. At least most places places further north got some out of this last cold spell! so it's slightly frustrating when most people want the SW to miss out again to get another snow event for them even though it more likely means that we may turn milder afterwards instead of getting a more prolonged cold spell. when will my turn come I wonder!? :cray:Ok the 12z run downgrades the following northerly as well I seriously hope its wrong!

Well I'm with you on this one, because I think we'd both be in our element if a frontal system stalled over SW England giving snowfalls February 1978-style while Tyne & Wear had sunshine and snow showers from a north-easterly blowing over the comparitively warm North Sea giving vigorous convection.

The area of real marginality is the south of England where the positioning of the low to the south means the difference between a few cold snowy days and a few days of rain and near-average temperatures. Also, flooding could well be a problem if this area of precipitation hangs around for a while, especially if it falls as sleet or rain.

Further north it stays cold on all outputs except for the UKMO with increasing chance of wintry showers firing in from the north and east and the frontal band perhaps stalling over the Midlands/N England for a time bringing some sleet & snow.

[Guest North Sea Snow Convection]

The GFS 12Z is a very exciting run, of course it comes with risks but thats what living in the UK is all about, no point in having days of cold and frosty weather with a boring return to mild at the end of it. Some Southern Nimbyism on the thread I think.

No, I don't think so Ian - rather some objective comment about the fact that despite some classic synoptics the models (so far this evening) are showing a real waste of these in terms of getting a cold spell that sustains beyond some regional snowfall courtesy of the low pressure. Even if I was in a snow zone as depicted by GFS - there would not be (in honesty) that much enthusiasm for a snowfall that melts very soon afterwards because there is no cold pattern in place over the Uk both to sustain it, as well provide further chances for further snowfall on a more widespread basis..

There is time for improvement in terms of the 'post low period' which is still nearly a week away. But so far, not much encouragement courtesy of the 12's, especially the UKMO which would mean that the snow zone as depicted on the GFS wouldn't even materialise.

[Rollo]

Strange evolution-yes-but anything is possible on this tiny island,I would however be almost certain that tomorrows charts differ considerably.

[cold snap]

In Summary there- the 12z GFS is good for the intial snowfall over wales, midlands NW, Ireland & Eastern scotland for potentially 2/3 day of snowy weather- where the threat of snow receeds back to the NE- then because the trough over Norway doesnt want to budge we end up on the southern side of the Polar front again because of it-

so 5-6 days of cold weather & snow for some-

UKMO is rain for all except Western Scotland- has all the cold air at 144 going westwards but North of the UK-

take your pick- but I doubt these runs are close on the reality yet-

S

Understand everthing Steve except trough over Norway? Whats wrong with it on 12Z?

Thankyou

[Snowyowl9]

Now theres no mild to speak of here about average maybe it you call 4.8c max

with a SW wind and still lying snow also here,and pack ice!!!

And cold charts like this coming back with avengence the 80`s

come back to mind and something that go well against the M***** era.

http://91.121.93.17/pics/Rtavn1801.png

http://91.121.93.17/pics/Rtavn1802.png

GW is overhyped,controversial maybe.

The charts we are seeing now for the time of year are the best since the 1980`s

[nick sussex]

Im really confused .Why is this run not so good?

Please can someone explain.because it looks okay to me

The gfs is okay but the ukmo is very disappointing and because of this any celebrations by members that may get some snow initially needs to be tempered by the ukmo which would quickly push the cold out of the way. We need the ecm to disagree totally with the ukmo and keep the low further south.

[Thundery wintry showers]

I don't see there being no cold pattern over the UK to sustain it? After the northerly outbreak high pressure becomes prominent to the north and low pressure has a real struggle coming up from the SW- result, cold easterly winds across the British Isles.

To be honest this kind of setup is always going to cause debate because of the different implications for different parts of the country. The GFS 12Z is an "upgrade" for the Midlands and N England because of the likelihood of frontal snow events but a "downgrade" for the south which stays in the milder air for a lot of the time. I don't think the 12Z, overall, is an upgrade or a downgrade- rather it brings a change in the likely distribution of snowfall.

UKMO has been out on its own for a while progging the lows further north meaning a lot of rain for most. I think we'd need to see ECMWF falling into line with it before it becomes a likely outcome.

[Frosty.]

Very annoying - it sunk our high - but it seems to be showing up on the all runs now including the METO T144

Don't take it personally, the weather doesn't care a hoot what we think and hope for. Seems like the downgrades are taking place already which perhaps already makes today's meto update obsolete as I type this. Where has the northely arctic flow gone between friday and early the following week?

Edited December 26, 2009 by Frosty039

[beng]

The gfs is okay but the ukmo is very disappointing and because of this any celebrations by members that may get some snow initially needs to be tempered by the ukmo which would quickly push the cold out of the way. We need the ecm to disagree totally with the ukmo and keep the low further south.

UKMO run looks quite plausible to me though - basically it simply delays the cold another couple of days over England/Wales. If you look at the Northern Hemisphere charts for it, you'll see the arctic high pushing down into Scandinavia by t144 - if there was a t168 chart, it would most likely show the next depression sweeping across the UK with a blizzard further South as the High pressure over Scandinavia delivers the necessary cold air into the system.

[phil nw.]

The GFS 12Z is a very exciting run, of course it comes with risks but thats what living in the UK is all about, no point in having days of cold and frosty weather with a boring return to mild at the end of it. Some Southern Nimbyism on the thread I think.

I tend to agree Ian.

To get a battleground scenario,by inference,it`s always gonna be an edgy setup whereby somewhere is cold and snowy just a short distance north of the rain and milder temps.

Details are not set for next week and as long as the channel low doesn`t track to far North then the cold air will come south.

Let`s not worry too much about later developments until we confirm how the low moves.

The overall pattern is still a cold one.

With the Scandi trough extending south and then west on our latitude we have to expect some trough disruption and complications over the UK,especially around the South.

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=0&carte=1

Unless the whole thing implodes in record time we will all get the cold again it`s likely though that more Southern locations will be prone to less cold incursions because of the pattern i have just described.

It`s still a sight better for cold lovers than in many recent Winters.

[nick sussex]

Here we go again with the UKMO at T144 - forget it - the boys at Exeter will.

I'm sorry but the verification stats don't back this assumption, its second to the ecm, i'm not saying it's right on this occasion but we can't just ignore it.

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

In all honesty the output we should be ditching is the gfs seeing as it ranks in 4rth place! I'm happy to go with the ecm upto 144hrs, if that backs the ukmo then the gfs will follow.

Edited December 26, 2009 by nick sussex

[SMU]

Understand everthing Steve except trough over Norway? Whats wrong with it on 12Z?

Thankyou

it blocks the steady westward movement of the sibrian high....

S

[Barb]

The Met Office themselves completely dismissed their own UKMO run yesterday so I wouldn't read too much into what it is showing. The other runs are consistently showing, including Met Office's own FAX charts, a decent set up in at least the medium term if you're looking for cold/snow (unless in SE).

[Thundery wintry showers]

That's for the Southern Hemisphere- for the Northern Hemisphere GFS was actually in 1st for the most recent update, but for the most part has tended to be 3rd behind UKMO/ECM. Meanwhile UKMO appears to have dropped off over the last five days or so, languishing in 4th.

[Guest North Sea Snow Convection]

It is quite clear there is a current trend atm to place parts (at least) of the Uk on the wrong side of the trough. In the case of the UKMO that extends over quite a large part of the UK. That is not therefore IMBYISM - it is an attempt to be objective about the trend for potentially a larger swathe of the Uk than might seem apparent than just from the 12z GFS not to get on the right side of the trough.

The cold pattern is locked on the north side of the trough, which while still uncertain, is not at this time playing ball in advecting a cold pattern consistently by the models across a large majority of the UK. Signs such as this have incresed since yesterday. So no. there is no clear enough signal that a cold pattern will be there to sustain it - IF the synoptics, especially from the UKMO play out. Irrespective of a Greenland High etc.

Surely that analysis is being general to the greater part of the UK, rather than 'southern dwelling' ??

[Methuselah]

Some folks just love to moan...In my 53 years' on this planet, I can recall only ONE three-month cold spell - 1963!

[Snowaddict]

Wish I could be enthuasiastic because the GFS Operational & GEFS Ensemble Mean suggest a 24-36 hour severe blizzard for all of Ireland..

However, the UKMO run, especially towards T+144 is very disappointing and if you compare the UKMO run @ T+144 with the overnight ECMWF @ T+168, they are certainly not a million miles apart...

If GFS were to verify then brilliant short term but we need a very good short term and long term ECMWF Operational tonight to restore confidence.

[Thundery wintry showers]

It is quite clear there is a current trend atm to place parts (at least) of the Uk on the wrong side of the trough. In the case of the UKMO that extends over quite a large part of the UK. That is not therefore IMBYISM - it is an attempt to be objective about the trend for potentially a larger swathe of the Uk than might seem apparent than just from the 12z GFS not to get on the right side of the trough.

...

Surely that analysis is being general to the greater part of the UK, rather than 'southern dwelling' ??

The disagreement, I think, came from the fact that earlier posts were referencing the GFS 12Z. Regarding the UKMO I agree, but I have my doubts about whether the UKMO is likely to come off. True, it's stuck to its ground, but in recent days it has often tended to be too progressive at bringing lows in from the SW- far more so than GFS and ECMWF.

[Snowaddict]

On the very latest verification stats update (may be necessary to hit F5) - ECMWF is a long way ahead of the pack by almost 10%..

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

Therefore, the ECMWF evolution is extremely important tonight in my opinion..

[Guest North Sea Snow Convection]

I tend to agree Ian.

To get a battleground scenario,by inference,it`s always gonna be an edgy setup whereby somewhere is cold and snowy just a short distance north of the rain and milder temps.

Details are not set for next week and as long as the channel low doesn`t track to far North then the cold air will come south.

Let`s not worry too much about later developments until we confirm how the low moves.

The overall pattern is still a cold one.

With the Scandi trough extending south and then west on our latitude we have to expect some trough disruption and complications over the UK,especially around the South.

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

Unless the whole thing implodes in record time we will all get the cold again it`s likely though that more Southern locations will be prone to less cold incursions because of the pattern i have just described.

It`s still a sight better for cold lovers than in many recent Winters.

The further north that the low tracks, and the more that the trough over Norway impedes the colder air - then the more that the timeframe for colder weather is pushed further out. In turn, more time for further things to go wrong.

The ECM will complete the 12's and then we can see fully. However, there is still time beyond the mid week period for changes, and further changes are almost inevitable, despite rather unencouraging output so far this evening.

[MR EXTREMES]

Some folks just love to moan...In my 53 years' on this planet, I can recall only ONE three-month cold spell - 1963! :lol:

i agree and it would seem the models are not what people want to see so my advice is move along to the next cold spell lol.

but in most cases it will be good from midlands north for a few days.

the models do not suggest a 63 or even a 81 style outcome it all very maginal except in places that are being predicted.

im sure the ecm will be not as good for most but better for some the gefs are sticking with cold to our north but a chance of much milder south.

cant do nothing its the weather.

Edited December 26, 2009 by badboy657

[Stu_London]

sorry but we have gone from a severe winter outbreak lasting 7-10 days+ to some localised transient frontal snow likely to be washed away in 48 hours within 24 hours of modelling output

That may be an upgrade to some but to me, the 18z was a downgrade from yesterdays 12z, the 0z was a downgrade from the 18z, the 06z was a downgrade from the 00z and now we have the 12z.

Actually, once the pattern started, the result was almost inevitable.

ECS is probably last chance saloon but I wouldn't hold my breath and whilst the 12z GFS does show a wintry outbreak, I wouldn't be suprised if that gets squeezed from both ends in future runs.

Personally, I blame West is Best - as soon as he started ramping it was sure to go mammary glands northwards. Anyone remember 'Summer starts on Sunday, 18 months ago'

:lol: :lol: