Model Output Discussion

[cooling climate]

Very encouraged by the ECM tonight again looking forward to the extended

ensembles.

Decent heights over the high Arctic which seem to be heading our way although beginning

to think we may have to look more to the north, northeast rather than east for the

upcoming cold spell.

[weather eater]

From optimism to despair in a very short space of time, my advise is stop taking model projections literally. Whatever they show mild or cold, past a certain stage they will be wrong, to one degree or another. The same problem happens every winter, where are we now average temperatures for the next few days wet and windy at times the rest is so much pie in the sky.

[ribster]

True, some foggy conditions and bit of fost around coming up to Christmas, then maybe a change to something a bit colder into January.

Of course its extraordinary that the continent does not see any real cold, even Greece misses out for a change!

Hope the Atlantic does not remain so strong too long though, hey theres always February though that might save the day. :lol:

Christmas? Jan? Feb? One minute no one is looking beyond 144, the next people are looking to Feb! I wouldn't be so sure about anything past Weds next week!

[Optimus Prime]

Just ignore them talking about Jan and Feb, those are the people that add nothing but drivel and negative input into the discussion.

[Nick L]

Just ignore them talking about Jan and Feb, those are the people that add nothing but drivel and negative input into the discussion.

And this adds positive input does it? :lol:

[I remember Atlantic 252]

I seem to remember we had similar faux cold last christmas as high pressure built north from france, maybe a repeat of that is likely to occur, the models have dramatically downgraded any prospect of true wintry synoptics this side of christmas but maybe something surprising will happen hopefully, the usual british winter pastime of chasing phantom cold snaps has now commenced.

Yeah and that led to a cold spell starting on new years day, I had snow on 4th-5th Jan quite a bit, was a decent cold spell from 26th dec to 7th Jan,

[Optimus Prime]

And this adds positive input does it? :lol:

No it doesn't which is why you should stick to the model discussion!

Does look like a typical westerly/mild December 70s weather to me which is what Joe Bastar'i was talking about looking at the models.

[nick sussex]

IMO a better evenings output, that doesn't mean theres anything much colder on the way but a chance the rain might finally be coming to an end as the much derided euro high looks to make an appearance in the extended outlook, i think it would be a relief to the UK just to get a couple of dry days with perhaps some inversion cold if the high can get far enough north, or faux cold as its been named in here.

The appearance of the euro high is a natural progression with the current pattern as the forcing of the trough to the west increases pressure over southern europe. Looking upstream they do expect pressure to rise across the eastern USA, this should reduce the energy in the jet, troughing should then be drawn further west.

http://www.meteo.psu.edu/~gadomski/ECMWF_12z/hgtcomp.html

Looking here the ecm and gfs both agree in increasing pressure in central southern europe and also pulling those negative anomalies further westwards.

The euro high is often derided in here during winter as it can hang around for quite a while, if it gets far enough north we do get surface cold but normally we see low heights to the north so that it eventually sinks with a return to mild zonal weather, this time if the trend continues we'll have at least some pressure rises to the north and so this does open up perhaps something a little more interesting later.

[I remember Atlantic 252]

Yes, I like to call it the 'modern cold' :lol:, it was a persistence of heights at mid-latitudes supported by the jet pattern. Whilst, bringing a break from the wind and rain, it rarely leads to anything better down the line with these Highs more often than not slipping into Europe, with plenty of time being wasted as the whole process is dragged out.

I know a typical christmas pudding cold spell but wanna see a repeat, if only the inversion -5°C stuff for a few days, even knowing the high will sink south

[bluearmy]

the split vortex now appearing around T144 on the models. As this timescale drops, i would hope that the output will get a better handle on how the blocking to the north will pan out. up until now, we have had pretty different options from every run. the trend over the past 24 hours is for greenland to become more blocked than seemed likely a few days ago. of course, this blocking will do us no good unless the atlantic quietens down or runs southeast into continental europe. although the higher heights modelled recently in a week to ten days to our south look to prevent this, JMA does remind us that the trough could still look to drive se at some point. GEM 00z and ECM 12z both offer a hope that by the end of next week the atlantic trough will begin to withdraw westwards. it all remains very uncertain and we will continue to see the odd carlsberg FI and ensemble runs whilst there is so much cold to our north and east.

What must not be overlooked is that should the frigid cold begin to march in our direction within a higher resolution, the atlantic wont look so powerful in the face of it. Then we really may need to get the prozac ready.

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

No comment necessary i'm afraid with the far off fi split becoming more defined and the cold losing 4 to 1.

Edited December 3, 2009 by bluearmy

[Jack Wales]

At this stage it looks as if arctic heights will be centred over northern canada / alaska and northern russia. With the jet as powerful as it is at the moment, nothing will be coming back westwards. We will be in the funnel between the two so all we can expect out of it is more severe storms, mild and rain.

[Cecil Hogmanay Melchett]

At this stage it looks as if arctic heights will be centred over northern canada / alaska and northern russia. With the jet as powerful as it is at the moment, nothing will be coming back westwards. We will be in the funnel between the two so all we can expect out of it is more severe storms, mild and rain.

+1

Agreed with that,as others have said,we're relying on FI for anything cold for the forseeable.

[Frosty.]

Yeah and that led to a cold spell starting on new years day, I had snow on 4th-5th Jan quite a bit, was a decent cold spell from 26th dec to 7th Jan,

Hopefully it will happen again around the same time, looks pretty mild and unsettled until then. I've seen enough of the models today..back for another round of model torture faux cold snap chasing tomorrow.

[dvdfjojo]

Maybe JCB but there is very little heights actually present over the north Poles, there are ridges obviously inbetween the polar vortex but its more surface based. As steve.M said you know its the real deal when you see the yellow colours come up in the charts, thats when you tend to have 552 heights which at the north pole tends to suggest a real blocking event. What the models are showing isn't anything close to that, and thus the highs we see over the north are simply reflections of the low pressure cells around it, remember for every trough/low there will be a ridge in there, may be all relative but there will still be one, and the blue highs (low heights) are not going to cut the mustard at all with a strong jet...because they are caused in effect by the jet and the PVs themselves...thats why you may see 1050-1060mbs high pressure cells which have low heights in topplers, then along comes a small weak lp and the whole lot will be destroyed because its not a strong high in the sense of whats needed.

Thanks very much for that explanation, KW, I've never realised why the blue highs get smashed so easily and you've explained perfectly why.

[Grimsby Snow Lover]

I am not sure if this is relevant or not but the high pressure over greenland is 10mb higher compared with the 12z at 147hr. It seems to be diverting the low in the Atlantic further south. Is this a good thing/bad thing? Would like to know. Also on a personal note could some one explain the difference with the bluey purple hp's and the orange hp's on the map. Thanks

Edited December 3, 2009 by Grimsby Snow Lover

[La Bise]

Where do I sign for a quiet period under a fat high, with mild days and frosty nights...? Please...

[cooling climate]

Nice FI on the way I think.

[Mark Bayley]

Nice FI on the way I think.

Easterly in FI which is good to look at Before hand it stays unsettled before perhaps turning drier. Quite mild at times. I think GP said that an easterly in the time frame the GFS is predicting was unlikely because something called GWO was stuck in phase four or five while the MJO was moving into the more favorable phase 7. Its hard learning all this technical stuff

Edited December 3, 2009 by mark bayley

[Snowstorm1]

Nice FI on the way I think.

YOUR OH SO RIGHT

[Grimsby Snow Lover]

Nice......Very nice. Its not too much to ask is it?

You beat me to it Snow storm

Edited December 3, 2009 by Grimsby Snow Lover

[ChartViewer]

Here we go another 18z Pub run showing the Easterly scenario..

[LomondSnowstorm]

The 18Z in FI shows the euro high pushing up, with a spell of drier weather, before bringing in an easterly towards the UK - I think we'd all be happy with that!

[Grimsby Snow Lover]

The end is pretty to look at too a strong North Easterly. Fingers crossed that we see the same thing over the next few runs and days!

[Cal]

Good ol pub run , not bothered about the orientation of the high at least it may allow some dry weather for a change , does look a classic though :lol: .

[Richie V]

Oh dear, More non plausable trash in Formular 1, what rubbish.