General Model Output Discussion

[nick sussex]

For areas further east along the south coast and towards the se the gfs 12hrs develops the shortwave further this will increase the precip but still have to see what the ukmo does. I doubt we'll know whats really going on till tomorrow, still alot of uncertainty and a complicated set up.

[Buzzit]

Hello All

Just a thought - there is a very significant solar eclipse happening on the 15th January and it has a wide arc through Eastern Europe, China, both Poles etc (but not UK or Western Europe) as there is evidence that an eclipse does create changes in local climate conditions, and based on the scope of the eclipse it could throw some strange changes into the model mix after the event - Im sure global models take absolutely no account of eclipses and as a result I will also be loathe to trust models based on output from the 15th.

[MisfitDog3]

Is there any evidence that eclipses have an effect on local climates other than in the very short term via reduced sunlight for a couple of minutes? Looking at this afternoons charts I suspect that Low is going to be getting towards the west of London before stopping.....

[cooling climate]

Well according to the 12z GFS there will be a significant snow event for England and wales later on

Tuesday and during Wednesday. In fact if this run is anywhere near the mark then there would likely

be a lot of disruption due to snow.

[nick sussex]

The smaller and not the most reliable GME at 132hrs is close to developing a trigger low which could go under the block. The GFS still more enthusiastic about an Atlantic push but unlikely to succeed with the block resisting, the se could still hang onto some colder Continental air.

Edited January 11, 2010 by nick sussex

[Thunder Snow]

Im still not convinced, we have been in this situation so many times. The milder air always pushes in front . I suppose this could be diffrent . According to the 12z i should have snow now (going by the precip chart). ive got light rain. :unsure:

[igloo]

Well according to the 12z GFS there will be a significant snow event for England and wales later on

Tuesday and during Wednesday. In fact if this run is anywhere near the mark then there would likely

be a lot of disruption due to snow.

looks like quite a big snow event followed by a rapid thaw by the end of the week and weekend i can see the plumbers having a bizzy time next week by todays outputs

[Iceberg]

Much nicer GFS at 168, more of a south/north WAA, further west in the Atlantic, stronger HP build and colder air already over the UK at 168Z.

[Eugene]

I think GFS 12Z and esp GME 12Z are starting to back up my thoughts of blocking highs repelling the atlantic and hardly any warm up north of the midlands and only a very brief near average snap for the midlands if at all :unsure:

[nick sussex]

Interesting here the Azores high could well aid another cold spell, just as it did before Xmas, also the Atlantic trough looks like digging further south. There seems to be a distinct lack of interest in this thread at the moment, is everyone bored of the cold weather?

Edited January 11, 2010 by nick sussex

[Methuselah]

It's model predictions like this that have flummoxed many, over the years...Sometimes, what seems like a straightforward transition to milder conditions turns-out to be anything but; we'll have to wait and see. But, after 23 consecutive days of lying snow (something I've not witnessed since 1963!) I'd put my money on the change - however temporary.

[snowingtequila]

looks like quite a big snow event followed by a rapid thaw by the end of the week and weekend i can see the plumbers having a bizzy time next week by todays outputs

Looking at GFS I cannot see temps getting much over 2, similar to today so wont be a rapid thaw and it will not have been so frozen that pipes will burst.

[Shiny_Bottom_1]

I would really hold up on the jumpings of joy on the GFS 12z ppn until the ensembles have come out. Over the last 7-10 days, the ppn forecasts by the op run have quite often been much higher than the other members (depending on the date and the location) at this range (and even lower).

Its not really in line with the other models on the current output, so certainly worth waiting longer.

Edited January 11, 2010 by Shiny_Bottom_1

[sandstorm2]

Personally I think the GFS has 'gone off on one' except this time it is building a powerful anticyclone to our east with a bit of an aid from the AH, lets just wait for it folks, see if the ensembles back it up.

SS"

[Steve Edgefield]

Interesting here the Azores high could well aid another cold spell, just as it did before Xmas, also the Atlantic trough looks like digging further south. There seems to be a distinct lack of interest in this thread at the moment, is everyone bored of the cold weather?

Not in the slightest - a little flat after the disappointment over the weekend's easterly (but probably just being greedy!). Just waiting & watching atm, seems to be a lot of uncertainty at a very short range. Will be interesting to see what wins out here. Keep your posts coming - I for one certainly read them with interest even if I don't post too often.

[cooling climate]

The UKMO also goes for a significant snow event Tuesday into Wednesday and then goes onto show

a low undercutting the block at t144 as well.

[Rollo]

The run is certainly within the realms of possibility but it does look all too easy for the High to return westwards.

[nick sussex]

Personally I think the GFS has 'gone off on one' except this time it is building a powerful anticyclone to our east with a bit of an aid from the AH, lets just wait for it folks, see if the ensembles back it up.

SS"

I suspect the ECM will back this as it's been trending that way already in its last few model runs. It's going to take a while to get back to the colder upper air though. The Azores high helped already this winter with the early stages of the pre Xmas cold spell. We still have to see exactly how the Atlantic trough sets up, we want this digging as far south as possible and negatively tilted. It's a developing situation but does open a way back to much colder weather but quite a few hurdles to get through before then.

[Snow Queen one]

I am still lurking. I have looked at the jet on the wetter site and it seems to be making a brief visit to our shores around Friday then goes back south for another holiday. Does this mean the colder weather will continue? If i read the charts right then by Sunday we are back to temps not exceeding 3deg in our neck of the woods colder elsewhere. The more north you are as ever the better chance of colder air.

[PB22]

The theme continues on the 12Z's so far of the milder end to the coming week as we draw up southerlies with an Atlantic origin. Double figure max's are still progged for the south by the weekend http://www.wzkarten.de/pics/Rtavn15017.html and this seems to be a feasible and consistent theme IMO. Always that bit colder the further north and east you are (as would be expected), but for many temperatures look like returning to near normal values by the weekend. Beyond this, well to be frank, its back to searching for the next cold spell in F.I.

The evolution on the UKMO T+144 chart isn't that great IMO, with the high to the east slowly drifting southeastwards, allowing Atlantic weather systems to take over, but I am sure there are plenty of people out there prepared to offer ifs and buts as to what may happen next, i.e. the Azores ridge heading northeastwards to then help the high to the east retrogress thanks to that cut off low over the south at T+144. The problem with that evolution is that by then there won't be an awful lot of deep cold air over the continent with that high over southwest Russia by T+144.

GFS T+168 shows the lack of deep cold air (by that I mean uppers below -10C) that I am talking about:

http://www.wzkarten.de/pics/Rtavn1682.html

[BLAST FROM THE PAST]

Interesting here the Azores high could well aid another cold spell, just as it did before Xmas, also the Atlantic trough looks like digging further south. There seems to be a distinct lack of interest in this thread at the moment, is everyone bored of the cold weather?

Hi Nick

I follow your posts closely as they always show good sense and very good understanding of synoptic set ups. This chart I will post from the 12z...I am very interested in and indeed with the whole run. I think this less cold incursion is temprary at present and renewed cold wil come back from the east [don't know if you saw my monthly update earlier].

http://charts.netweather.tv/gfsimages/gfs.20100111/12/144/h850t850eu.png

I think this is progged a tad too far north BUT the idea is correct with block re-asserting and the first of 2-3 LPs attacking on southerly track [Channel/N France.] I think a few surprises are coming for some re the model outlook and indeed TEITS alluded to it earlier.

Paul B I would say its continental based cold with the Atlantic trying to stir it up

BFTP

Edited January 11, 2010 by BLAST FROM THE PAST

[phil nw.]

I suspect the ECM will back this as it's been trending that way already in its last few model runs. It's going to take a while to get back to the colder upper air though. The Azores high helped already this winter with the early stages of the pre Xmas cold spell. We still have to see exactly how the Atlantic trough sets up, we want this digging as far south as possible and negatively tilted. It's a developing situation but does open a way back to much colder weather but quite a few hurdles to get through before then.

Hi Nick,

Yes GFS still showing,shall i say,a less cold trend by the weekend but the development of that shortwave over England midweek complicates things and shows some resistence from the cold air ahead of the front.

This mornings ECM ext ens showed a more colder runs further out indicating that the block to the East is sticking around.

What we don`t want is the Atlantic trough seting up just to our West like in Nov.which would leave the uk under the influence of the Atlantic.

Some attempts at undercutting are still being shown on this run but it doesn`t quite complete the job in the nearterm on this run.

http://www.wetterzentrale.de/pics/Rtavn1441.png

Just to much strenth in the piece of vortex to our NW.

Meanwhile there could be quite a bit of snow Tues/Weds for some areas,particularly Wales and much of the Midlands

http://www.wetterzentrale.de/pics/Rtavn484.png

http://www.wetterzentrale.de/pics/Rtavn4817.png

http://www.wetterzentrale.de/pics/Rtavn4810.png

http://www.wetterzentrale.de/pics/Rtavn482.png

On this run we have the percip.low temps and dewpoints as the front approaches.

Probably snow for parts of the South West too,although more chance of this turning to rain eventually.

[Thundery wintry showers]

I would really hold up on the jumpings of joy on the GFS 12z ppn until the ensembles have come out. Over the last 7-10 days, the ppn forecasts by the op run have quite often been much higher than the other members (depending on the date and the location) at this range (and even lower).

Its not really in line with the other models on the current output, so certainly worth waiting longer.

Not entirely true- the ECMWF showed a similar synoptic evolution this morning, but had sent a colder pool of upper air across from the east, giving us a pretty cold-looking easterly with sunshine & snow showers likely. GFS's version is much more modified and would not give widespread snowfalls. UKMO's T+144 chart also shows a similar trend- the Atlantic looks strong but that low over Britain, when shown on model outputs, has a tendency to be progged to slip SE allowing easterlies in.

[MR EXTREMES]

I suspect the ECM will back this as it's been trending that way already in its last few model runs. It's going to take a while to get back to the colder upper air though. The Azores high helped already this winter with the early stages of the pre Xmas cold spell. We still have to see exactly how the Atlantic trough sets up, we want this digging as far south as possible and negatively tilted. It's a developing situation but does open a way back to much colder weather but quite a few hurdles to get through before then.

it also opens a path fro the jet to run over the azores high which might not be so good.

as for the wednesday event im very skeptical indeed after sundays none event i think the models are in a mess and just not latching onto anything sustained just yet.

i still convinced the alantic will win by the weekend but colder futher north.

but sayting this never to mild perhapes average or just slightly under.

[Polar Bear]

Interesting here the Azores high could well aid another cold spell, just as it did before Xmas, also the Atlantic trough looks like digging further south. There seems to be a distinct lack of interest in this thread at the moment, is everyone bored of the cold weather?

Nar no bored just think alot are focusing on the short range and getting heavily into it....

Once things start thawing a bit I reckon this thread will be hot, hot, hot and I am still lurking....