Model Output Discussion 4th Dec.2013-12z onwards.

[IDO]

Wheres Steve Murr when you need him.

Christmas Day:

Third op run in a row hinting at something wintry on the big day.

Mainly Scotland at the moment:

Still 5-1 Glasgow snow on the day.

Edited December 13, 2013 by i'm dreaming of...

[phil nw.]

Wheres Steve Murr when you need him.

 

Christmas Day: gfs-2-288.png

 

 Third op run in a row hinting at something wintry on the big day.

 

 

Mainly Scotland at the moment: viewimage (74).png

Not wishing to be a Scrooge but for a full picture re.snow risk- any snowfall currently modeled there is for the Higher levels only.

If we check the freezing levels around that period we are looking at 600mtrs and above.

 

Of course these are a guide but as we are highlighting them we should try to represent fully what they are showing.

These levels may come down a little in future runs depending on the depth of any polar air that may enter the mix but for lower levels in this mobile westerly pattern we will be struggling to see anything.

[Purga]

All hail the mighty vortex!

 

Certainly no sign of any northern blocking in our neck of the woods throughout the entire 12z run.

[bluearmy]

I wonder what happens if the ukmo has stumbled across a new trend as soon as day 6.........................

[fergieweather]

 

Not wishing to be a Scrooge but for a full picture re.snow risk- any snowfall currently modeled there is for the Higher levels only.

If we check the freezing levels around that period we are looking at 600mtrs and above.

1.png2.png

 

Of course these are a guide but as we are highlighting them we should try to represent fully what they are showing.

These levels may come down a little in future runs depending on the depth of any polar air that may enter the mix but for lower levels in this mobile westerly pattern we will be struggling to see anything.

Agreed - we are way off being deterministic on how the WBFL's will sit (let alone way off firming on the broader synoptic picture or the phasing/scope of PPN). The GFS PPN type modelling is solely indicative and shouldn't be taken literally - especially at that timeframe. All that said, clearly the signal is one to watch.

[Barry12]

All hail the mighty vortex!

 

Certainly no sign of any northern blocking in our neck of the woods throughout the entire 12z run.

That's not a bad chart at all, would be pretty cold for us as well.

[TSNWK]

I wonder what happens if the ukmo has stumbled across a new trend as soon as day 6.........................

? you seeing something there BA

[Captain Shortwave]

I wonder what happens if the ukmo has stumbled across a new trend as soon as day 6.........................

That is interesting

Possible development of a cut off low over central Russia with heights building between northern Scandinavia and Siberia. This would steer the Atlantic train straight through the UK into central Europe. As opposed to the GFS which pushes the low on a more usual track towards Scandinavia and beyond

The UKMO might develop into something decent for the north at least. Cool/cold and unsettled,

Edited December 13, 2013 by Captain shortwave

[UV-RAY]

All hail the mighty vortex!

 

Certainly no sign of any northern blocking in our neck of the woods throughout the entire 12z run.

Cracking chart for IMBY, would bring a very disturbed and potentially snowy chart for me.

[cooling climate]

The CDAS global temperature anomalies at mid to lower levels of

the stratosphere are very intriging still and I would not be

surprised to see big changes in model output in the days to come.

A case could even be made for big height rises to the east/north

east with the vortex pushed back northwest and a possible cold

continental flow developing.

The models are not showing anything like this at the moment but

the 50mb temp anomalies are suggestive perhaps of something along

these lines.

[fergieweather]

 

The CDAS global temperature anomalies at mid to lower levels of

the stratosphere are very intriging still and I would not be

surprised to see big changes in model output in the days to come.

A case could even be made for big height rises to the east/north

east with the vortex pushed back northwest and a possible cold

continental flow developing.

The models are not showing anything like this at the moment but

the 50mb temp anomalies are suggestive perhaps of something along

these lines.

temp50anim 13-12-13.gif

Interesting. Many here will recall the model lag issues early 2013 with SSW 'feed-down' into their domain; exception being GloSea4 which has been adapted to account for capturing such. I'll enquire where it heads in terms of Jan...

[legritter]

Well current models paint a very zonal set up with some very interesting days ahead and eventually some colder air being dragged closer to our shores .Also the prospect of New weather features popping up on every individual model run .At this time last Friday the 6th of December ,one week into winter many posters including myself Feared Alimpet high ,euro high ,dank dark mild days no wind no rain ,no prospects of hope at the end of the tunnel . I  myself actually today have taken a look at last weeks posts and i would recommend this to new posters and learners alike ,it certainly shows you that a week in meteorology is a long time ,so double that nearly for christmas day /boxing day and this is why we cannot be sure  what will be the synoptic picture for that day .so when looking at the end of The GFS run remember its only a possibility ,so with Plenty of winter left we are in with a chance ,i will catch up after tonights main runs 

[Panayiotis]

Black hole incoming on the GEM @240hrs! I wonder what conditions will be like if we were in the centre? 

Edited December 13, 2013 by Panayiotis

[Dan the Man]

That model has gone haywire! What sort of conditions, would it be like?!

[EML Network]

Iceland has done a runner and no surprize with a central pressure of 910mb

 

[Convective]

Black hole incoming on the GEM @240hrs! I wonder what conditions will be like if we were in the centre? 

 

 

Something like this?

 

 

Amazing how much the models have changed in a matter of days. Just goes to show how we must always expect the unexpected!

[nick sussex]

Although the GFS lower resolution suggests some interest it's dreadful, the model bias in these set ups is to try and take the jet further south but there is no trigger for this.

 

A rounded PV uniform as shown in the lower resolution will only go one way, come the time the jet axis will be changed to a more sw/ne and the pattern taken further north.

 

Now if the GFS had shown high pressure building out of Alaska towards the pole then a southwards adjustment in the jet is possible but you have to see the PV elongating and leaving a gap over northern Greenland, this was suggested in some previous GFS lower resolutions.

 

The UKMO at T144hrs shows some interest but I can't remember the last time it actually picked a colder solution that verified at that timeframe, generally its the model that harpoons cold at that timeframe when perhaps the GFS or ECM suggest it.

 

We'll wait to see what the ECM suggests but the GFS lower resolution IMO is very disappointing, we have to hope that the ECM doesn't agree with that.

 

PS I hope people don't think I'm just being miserable! regarding cold prospects on the GFS but its really not good in the lower resolution,with a PV this strong you need something to attack it and as you can see the lower resolution is firing blanks!

Edited December 13, 2013 by nick sussex

[MR EXTREMES]

to be honest neither the ukmo or the gfs are likely to be right its more a case of the vortex is really messing with the model outputs because of its extreme strength.

and will discount everything with in the next 24hrs none of the models have the teleconnections to support anything more than a stormy wet with wintry at times at height around Scotland maybe northern England.

 

this is were people can really be lead down the garden path!

its pretty much north south split with mild wet at times, windy for England.

 

but stormy at times cooler to colder with wintry weather in the highest hills and mountains further north. 

with heights still running from azores through into Europe so realistic view would be a continuation of what is coming through the rest of December.

and nothing is showing to disrupt the vortex so its a waiting game.

[Captain Shortwave]

Although the GFS lower resolution suggests some interest it's dreadful, the model bias in these set ups is to try and take the jet further south but there is no trigger for this.

 

A rounded PV uniform as shown in the lower resolution will only go one way, come the time the jet axis will be changed to a more sw/ne and the pattern taken further north.

 

Now if the GFS had shown high pressure building out of Alaska towards the pole then a southwards adjustment in the jet is possible but you have to see the PV elongating and leaving a gap over northern Greenland, this was suggested in some previous GFS lower resolutions.

 

The UKMO at T144hrs shows some interest but I can't remember the last time it actually picked a colder solution that verified at that timeframe, generally its the model that harpoons cold at that timeframe when perhaps the GFS or ECM suggest it.

 

We'll wait to see what the ECM suggests but the GFS lower resolution IMO is very disappointing, we have to hope that the ECM doesn't agree with that.

 

PS I hope people don't think I'm just being miserable! regarding cold prospects on the GFS but its really not good in the lower resolution,with a PV this strong you need something to attack it and as you can see the lower resolution is firing blanks!

I can, that cooler spell in October was picked out by the UKMO whilst all the other models wanted a Euro high and southerly winds for the foreseeable. I will give it a chance, if it replicates the run tomorrow morning and there's movement from the ECM then we might be finally starting to see some positive signs in the output.

[bluearmy]

 

? you seeing something there BA

 if we are to break out of this seemingly 'endless mobility' (according to some), a model has to find a new pattern at some stage. day 6 would seem a bit early. noticeable that any gefs members that show the slightest propensity to send the jet se as the trough digs a bit south throw a big ridge up ahead of them. just something to keep a look out for.re the gem chart - that 'black hole' has an associated thickness of 535 dam and uppers around freezing. inside the hole wouldn't be too bad at all. around the periphery a tad blowy though!re the strat activity. i note that the ecm lower strat/upper trop zonal winds are keen to show a lack of activity above 70N. that would allow for some blocking to establish higher up and we've seen some op runs showing arctic highs around the pole, especially the siberian side. HLB looks an outside bet at the moment but cannot be discounted - most credible idea would seem to be polar blocking forcing the jet firther south as per some of the GFS fi runs recently.all the above shows that we miles away from Bartlett boredom.

[Stuie]

I presume this is the cluster of low pressure systems to our north that has been mentioned many times here. Will these all be driven along in conjunction with the jet stream?

[nick sussex]

I can, that cooler spell in October was picked out by the UKMO whilst all the other models wanted a Euro high and southerly winds for the foreseeable. I will give it a chance, if it replicates the run tomorrow morning and there's movement from the ECM then we might be finally starting to see some positive signs in the output.

You're younger so your memories better than mine! lol I hope you're right, the UKMO is okay compared to the GFS. The PV is expected to relocate towards Canada and so we're going to need some help from the ne to put some forcing on all that energy spilling east to try and get a more favourable jet axis.

[bluearmy]

 

You're younger so your memories better than mine! lol I hope you're right, the UKMO is okay compared to the GFS. The PV is expected to relocate towards Canada and so we're going to need some help from the ne to put some forcing on all that energy spilling east to try and get a more favourable jet axis.

 TTbh Nick, the strong jet could work for us IF we can force some blocking to our NE that is able to push west. the high heights to our south do look like they are prepared to retrogress back into the atlantic so we could force a euro trough if the jet can be deflected south. i suspect that the only block able to do that to this jet would be a retrograding siberian block but we arent seeing that currently modelled. one thing to watch over the next few days are these little pockets of higher heights that are pushed into the polar region and then cut off. historically, they can lead to all sorts of fun within a week or so. on the flip side, they can just get mixed out quite quickly.

[IDO]

Yes the op is ordinary but the control has potential, dragging the jet south via a trigger low off the PV trough:

 

 

 

Not perfect, but cooler and this would enable pressure to build over the N Pacific region and perhaps link up with the Euro/Russia ridge. About the best we can hope for, cold wise, before January though not much support for that in the GEFS.

 

To be honest nearly every member at T384 is different to the others so we are entering a very volatile period, so there is possible reason to believe we might start seeing real cold snowy charts, though no sign yet.

 

 

[Cloud 10]

Not wishing to be a Scrooge but for a full picture re.snow risk- any snowfall currently modeled there is for the Higher levels only.

If we check the freezing levels around that period we are looking at 600mtrs and above.

1.png2.png

 

Of course these are a guide but as we are highlighting them we should try to represent fully what they are showing.

These levels may come down a little in future runs depending on the depth of any polar air that may enter the mix but for lower levels in this mobile westerly pattern we will be struggling to see anything.

 

I would expect to see snow falling to quite low levels if that christmas day chart verified due 

to depth of cold air and low dewpoints and temperatures.

 

 

dewpoint..  temps..

 

 

All pretty much academic at this range,but would still make for some nervous bookies.