Model Output Discussion 1200 hrs 15/11/14

[Cloud 10]

The latest 120 hrs fax chart looks rather complicated and shows well how the UK is in the battleground between the block to the East and the Atlantic trying to push through from the West.

 

[Sean19]

18Z GFS showing so many blobs on snow risk from 200+

 

First time I have seen it this year, won't come off of course but it has made me smile to see it!

Please could you link me to the model?

[gottolovethisweather]

The latest 120 hrs fax chart looks rather complicated and shows well how the UK is in the battleground between the block to the East and the Atlantic trying to push through from the West.

 

fax120s.gif

 

Indeed C10, I'm surmising that Wednesday's low pressure system up from Biscay is not being handled well across the various outputs right now as there is so much divergence beyond this. Personally, I am not looking beyond that timeframe, for any persistent signs as to what we can expect in the UK after your presented chart. Adding weight to my theory is the well-documented scatter that is apparent in the GEFS ensembles spreads (and probably ECM etc.) beyond next Wednesday. The NH Jet continues to dive on a NW to SE axis and be positioned ever Southwards out in the Mid-Atlantic at that juncture. This aspect gets pushed back progressively in time over successive 12z runs. Plenty to play for yet and the predominantly cooler uppers set to occur over central and eastern Europe during the middle part of next week, pushes ever slowly westwards should also aid to stave off the Atlantic until nearer late November at this rate, so yes the STALEMATE continues unabated.  :friends:Incidentally this last aspect has been dropped by the pub run, no worries there unless this eventually becomes the new trend. 

 

Sorry if the above is slightly rambling but hopefully makes sense to some, tis high time I had some kip. 

Edited November 21, 2014 by gottolovethisweather

[Smiler1709]

A nice positive though from the current set up being forecast is that there maybe a lack of significant cold and snow, but it will trend colder and feel very fresh in the north west winds, bringing wintry weather to the high ground in Scotland but also giving frosts when the sky's clear long enough.

That to me is already more positive than last winters awful mild mush and continued zonal theme.

We also have the added bonus of the models being very uncertain with the block to our east, over the next week it could go either way. It's to differcult to call so we just have to wait and see.

[Frosty.]

I disagree with certain comments saying there is no sign of anything cold. From what I have seen, there is an increasing risk of frost at times in the north and east, especially the NE with high pressure early next week before it gradually becomes unsettled from the southwest later next week but even then the block holds further east with an ongoing risk of frost and fog. It doesn't look mild after the next few days, daytime temps look closer to average.

[blizzard81]

I wouldn't be surprised if the ECM was way off the mark here. I get the feeling that we are going to have to face a period of mobility towards the end of Nov and first third of Dec before we experience anything remotely cold this COMING winter. I emphasise the word 'coming', because as I post this, we are still 10 days away from the start of winter.

[gottolovethisweather]

I disagree with certain comments saying there is no sign of anything cold. From what I have seen, there is an increasing risk of frost at times in the north and east, especially the NE with high pressure early next week before it gradually becomes unsettled from the southwest later next week but even then the block holds further east with an ongoing risk of frost and fog. It doesn't look mild after the next few days, daytime temps look closer to average.

 

Yes Frosty agreed, it will probably be your namesake on the forthcoming Sunday and Monday nights, more especially for those in prone locations, for it (Frosts) are likely away from the NW and SW parts of the mainland. After the mild/very mild blip for a few tomorrow into Sunday and after the nuisance rainfall, next week is set to be cooler with nearer Average Maxes by day and cool where mist struggles to clear. Forecasting Wednesday and beyond with any accuracy as I alluded to earlier, is very tricky and the eventual UK synoptics could be anything by then. DEEP cold of course is nowhere near our shores for now and ironically, the coldest uppers of the season might well come to us from off the Atlantic. 

Edited November 21, 2014 by gottolovethisweather

[damianslaw]

I disagree with certain comments saying there is no sign of anything cold. From what I have seen, there is an increasing risk of frost at times in the north and east, especially the NE with high pressure early next week before it gradually becomes unsettled from the southwest later next week but even then the block holds further east with an ongoing risk of frost and fog. It doesn't look mild after the next few days, daytime temps look closer to average.

 

 

Yes temperatures next week will be much nearer average and in some places a little below average with maxes of 6-7 degrees and lows in the 2-4 degree range. At this time of year slack set ups can produce quite chilly conditions.

 

The general outlook is a tame one for the time of year, with very little in the way of stormy very wet conditions which can dominate late Nov/early Dec, rain at times, near average temps with return of fog and frost in places.

 

It feels we are in a bit of a stalemate overall though and waiting for a major shake up, but no dominate force wants to take over, this in itself is very noteworthy given how on average the atlantic is at its most powerful now.

 

The models have yoyoed around so much in recent days, they are clearly struggling to foresee longer term patterns, only 2-3 days ago we were staring at a deep seated southerly..

[Barry12]

I wouldn't be surprised if the ECM was way off the mark here. I get the feeling that we are going to have to face a period of mobility towards the end of Nov and first third of Dec before we experience anything remotely cold this COMING winter. I emphasise the word 'coming', because as I post this, we are still 10 days away from the start of winter.

 

You gotta give some evidence for this rather than just a 'feeling'...

[knocker]

Can;t see much evidence of change with the GFS but the P wants to disappear the block.

Charts courtesy weatherbell.com

Edited November 21, 2014 by knocker

[Catacol]

Have they? I've not seen anything worded so bullishly... it's the status-quo that's causing headaches for medium range forecasters.

That's what is so encouraging from a broad brush approach. Signs are that the vortex is having a tough time, and the wave 1 assault at the top of the strat will eventually propogate downwards - and some signs of continued wave 2 attacks also. Meanwhile the tropospheric pattern is also less dynamic - hence the reality of an ongoing status quo battle which currently sees us on the warm side of the trough.

 

Last year everything powered up and up.... this year I think we are going to see a more retrograde pattern as the power of the Siberian block, enhanced by warming events in the stratosphere, wins the battle of the atlantic in the longer term. Wiser heads than mine are seeing a proper assault on the vortex later in December.... that being the case we can look forward to variable and potentially exciting output in Jan and Feb. For Dec there is a chance that we might see a blocked pattern develop from Scandy - perhaps with a block sitting over the UK? - but it is very hard to call. MJO composites are - to my eye - not giving any strong indications at present and it all looks very finely balanced as we head into December.

 

For my part I think we will see increasingly anti cyclonic conditions develop though without being properly cold - and systems will continue to move on a NW/SE tilt running up against the block and perhaps giving us some heavy rain at times. But at some point I think one of these lows will act as a trigger and advect the proper cold closer to our shores. But not for another 4 weeks or more? Hoping to be proved wrong on that with an earlier arrival of colder 850s but low confidence on that. However all MUCH more interesting than last year when the strat profile frankly was awful and the straws we were clutching all gathered around the possibility of a warming event in late January, something that came - and then bounced - straight off a supercharged vortex. Not so in 2014/15!!

[Nouska]

Please could you link me to the model?

 

The GFS run with precipitation charts - the white hatched lines indicate snow. This is too far ahead to be of any use as a forecast but you can follow to see how it changes. 

 

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=2

 

The low res part of the run is a good example of how quickly Europe can cool down with the right synoptic set up.

 

 

[nick sussex]

The ECM and GFS and GFS P have broadly the same evolutions. However you'll see  it all unravels on both GFS's in how that low exiting the eastern USA phases with troughing near the UK.

 

As the GFS's phase all the energy gets thrown ne, whereas the ECM the low phases more favourably pulling some of the PV nw whilst the troughing splits, its for this reason that this type of pattern gets a red warning!

 

The extended NCEP prognostic discussions commented on the differences in the ensemble suite of the GEFS and the ECM, the former flatter the latter more amplified. They actually preferred the GEFS for the 6 to 10 day outlook, although that discussion didn't include the 12hrs ECM ensembles.

 

Effectively because of the set up its essential to maintain enough upstream amplification to get over the first hurdle which is the trough splitting and energy shearing nw  and se. Even before then we have some small but noticeable differences with shortwave phasing to the ne.

 

Overall a very messy and complicated picture, certainly not a time to be trusting any of the outputs at longer range.

Edited November 21, 2014 by nick sussex

[Sean19]

Thank you. I will use this for educational purposes. 

 

The GFS run with precipitation charts - the white hatched lines indicate snow. This is too far ahead to be of any use as a forecast but you can follow to see how it changes. 

 

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=2

 

The low res part of the run is a good example of how quickly Europe can cool down with the right synoptic set up.

 

 

[Joe Levy]

The GFS ens are rolling out and though well into FI, there are several options shown that produce cold, blocked weather.

It's worth scrolling through them to have a look. However equally there are plenty that are much more mobile with wet and windy conditions. (though note how blocking is a common theme across the set, just the location is a lot more complicated!)

So in summary things are far from certain!

[Mapantz]

The GFS ens are rolling out and though well into FI, there are several options shown that produce cold, blocked weather.

It's worth scrolling through them to have a look. However equally there are plenty that are much more mobile with wet and windy conditions. (though note how blocking is a common theme across the set, just the location is a lot more complicated!)

So in summary things are far from certain!

Nicely put. There are perfectly good arguments for both sides of the camp which makes things very difficult at the moment. Nobody is right or wrong in their analysis for the time being- not surprising there are headaches for professional forecasters!? I just hope there is a breakthrough, and not a continuous stalemate throughout Winter.. Unlikely but you never know!

Edited November 22, 2014 by Mapantz

[Polar Maritime]

Maybe a few sleet/snow chances towards the end of next week, Especially for elevated locations as chilly Pm air digs S/E over the UK. The wind chill would make it feel raw. 

 

Edited November 22, 2014 by Polar Maritime

[kumquat]

Talk about a perpetual motion machine (with a bit of chaos thrown in somewhere)

 

It's a Real Catch 22 slow mobile pattern from West to East

The warm air escaping the hot equatorial regions of Africa northwards is both fueling the Siberian High to the North East and reinvigorating the Vortex segment over Greeny/Canada to the North West. The mildish (debatable) plume we're seeing right through the UK over the next week or so giving the sourthernlies is reinforcing both as it hits the cold air around the Greenland East Coast and splits its wings both ways. A relatively strong Azores high is perpetuating the energy feed into the powerhouse vortex segment that's seeming to drift towards the Med. Until something gives, somewhere, there's no short-term end to this fearsome engine.

[KTtom]

I have been model watching for many yeard but two charts really jumped out at me this morning, the first from the UKMO showing probably the longes southerly draw I have ever seen...

 

 

The second, and if anyone doesn't quite understand the magnitude of the east west battle regarding heights, then this is a stunning example of 2 contrasting pressures types and how the UK is bang in the battle ground.

 

[knocker]

One of the things that stands out this morning is the difference between the GFS and the P in dealing with this complicated set up. Just a couple of charts that exemplifies this at T180. After that the P progresses the intrusion of the ridge from the SW. Not much point in dwelling on this as it's obviously an analysis that is still fluid but just to add for the majority of the run to T240 the P has temps above average.

Charts weatherbell.com

Edited November 22, 2014 by knocker

[Captain Shortwave]

Certainly a move towards a more westerly flow as we go into week 2. Caused by a poor upstream pattern which allows the Azores high to move into a more typical position (Iberia/France).

GFS Parallel

 

The old GFS looks a little better and stays that way from low resolution

The GEM has a Arctic ridge on our side and rather unsettled conditions.

A very fluid situation but a model suite which certainly sets us back a little bit. Lets hope for better later.

 

The GFS ens keep the battle going to around day 10 before the high sinks and allows a more south westerly flow to develop.

[bluearmy]

Pretty progressive NWP ops this morning - gem offers the only solace for those wanting to avoid increased mobility to our north and northeast. Ukmo doesn't go far enough to show where it's headed. The gefs are in a much more blocked place.

part of me think a spell of mobility at thus time of year might be no issue as it will give us a chance to see how long before it becomes blocked again. ( a good forward indicator). Then again, flattening of the pattern could remove the trop wave input to the lower strat which could be a potent is issue re a strengthening mid/lower strat vortex.

Interesting to see if the ECM ens follow the progressive nature of the op ?

[Ali1977]

I think we need to get a good westerly flow, get rid of the high to the East and hope for some WAA that will link with the high we've pushed way East...That should leave a nice sausage high to our North for Xmas.....This stalemate between flows doesn't seem to want to shift for quite some time, and I can't see the high winning.

[MR EXTREMES]

Certainly a move towards a more westerly flow as we go into week 2. Caused by a poor upstream pattern which allows the Azores high to move into a more typical position (Iberia/France).

GFS Parallel

 

The old GFS looks a little better and stays that way from low resolution

The GEM has a Arctic ridge on our side and rather unsettled conditions.

A very fluid situation but a model suite which certainly sets us back a little bit. Lets hope for better later.

 

The GFS ens keep the battle going to around day 10 before the high sinks and allows a more south westerly flow to develop.

This last chart does not show sw flow looks more North west flow windy cold and wet.

[Captain Shortwave]

This last chart does not show sw flow looks more North west flow windy cold and wet.

Actually the wind is predominantly southerly at that point with the exception of the far west, not particularly cool either with 850s above 0C across the board. Splitting hairs anyway as beyond that we see the Atlantic westerlies push through.

 

Also we now have the ECM ens

Quite a similar story to the operational really.

As I said though the models are not being consistent and we could be back to more blocked charts later.