Model Output Discussion 17th Dec.2013-12z onwards.

[swilliam]

Colder rain..

Wrong

[weather eater]

Yes I’m afraid those of us waiting for a knight on a white charge to appear and banish the zonal express, we are going to have to wait a while longer, while I’m sure some will look to salvage something from this run by pointing at some colder interludes, in reality this run is a much use to those seeking a proper cold set-up as a (for those acquainted with the thick of it) marzipan D****e.

[Paul White.]

Colder rain..

Sorry bud but if that chart verified has shown it would be heavy wintertime showers and periods of snow and further north the more chance

[Tim Bland]

Colder rain..

With circa -6 850 uppers and sub 528 Dam I would say away from the coasts it should be snow. Long way off to analyse in detail but worth remembering that the best snowfalls, in most parts of the uk, come from marginal cold zonal events not cold dry northerlies.

[bluearmy]

some colder (mostly cyclonic & some deeply so) solutions in there out through T+240 to T+360 but also a raft of possible synoptic types, as expected.

Any word on the 30 day 'cold possibility' Ian? Is it glosea 4 or potential cold clusters at day 15?

[weather eater]

Is it worth arguing over its deep FI, a few days ago something not too dissimilar was being shown for the 4th and now look at it, never mind snow or cold rain the likelihood is SWlys, wind, mildish and bog standard rain.

Edited December 29, 2013 by weather eater

[phil nw.]

Good evening everyone i hope you all enjoyed some good times over the last few days.

I havent followed the outputs much over the last week but looking at today's runs very little has changed since.

Still no sign of a break from the Westerly pattern in sight with periods of wind and rain coming through the UK over the next week or so.

The ens means in week 2 continue to show the core of lowest heights still around the Greenland area

http://www.wetterzentrale.de/pics/Reem2401.gif

http://www.wetterzentrale.de/pics/Rz500m10.gif

 

Temperatures never far from average as can be seen from the Manchester ens graph

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

 

so a typical Atlantic set up looks likely to continue into the first week of the new year.

 

Something to keep eye on are the warmings to the higher Stratosphere showing up in the GFS runs which are gradually slowing the mean zonal winds at the top levels and squeezing the vortex like this

http://modeles.meteociel.fr/modeles/gfs/runs/2013122918/gfsnh-10-174.png?18

 

so far the vortex has reformed after each bout of wave breaking.

We really need these events to repeat to further undermine it's strength and allow some better build of high pressure further north to help change this pattern that we are in.

Edited December 29, 2013 by phil nw.

[TSNWK]

With circa -6 850 uppers and sub 528 Dam I would say away from the coasts it should be snow. Long way off to analyse in detail but worth remembering that the best snowfalls, in most parts of the uk, come from marginal cold zonal events not cold dry northerlies.

Noted. Maybe it's a sign of how poor the situation is at the moment that border line snow events over two weeks away are a discussion item this evening.

[492]

510 thicknesses reach mid atlantic (50N  31W) on UKMO 120 FAX with sub 528 air approacing uk.

[Tim Bland]

Noted. Maybe it's a sign of how poor the situation is at the moment that border line snow events over two weeks away are a discussion item this evening.

Granted ! We have retain some interest while we wait for anything really wintry though. I think we have been spoilt in recent winters, what we are seeing Is an average uk winter

[fergieweather]

Any word on the 30 day 'cold possibility' Ian? Is it glosea 4 or potential cold clusters at day 15?

The latter I believe. Nothing to scare the horses re cold (in strictest sense) until at least mid-Jan, reckon UKMO, but frankly the fixation for now is understandably on rainfall & (to some degree) wind issues for the forseeable. High confidence on the unsettled westerly regime through early to (at least) mid-Jan, but with Pm or rPm phases causing the cooling trend seen in EC ENS... snow/heavy snow for Scotland at times but Exeter stress range of synoptic outcomes into further reaches of trend period, thus confidence declining later into Jan. So, all in keeping with current output available on public websites.

[TSNWK]

Granted ! We have retain some interest while we wait for anything really wintry though. I think we have been spoilt in recent winters, what we are seeing Is an average uk winter

Yep i agree. The majority of us on here at the moment are looking for the same thing I think. A little bit of eye candy every so often is good for the soul as we solider on in our quest. Roll on the 00z onwards.........Cheer

[Jason M]

Wrong

gfs-2-372.png

Sorry, pet hate of mine when someone starts a conversation with 'wrong' :-)

In truth he is probably not far off being correct as snow would be limited to high ground in all likelihood due to considerable modification of the air mass following a long track over the Atlantic. With such a long fetch you could probably add 9 to the 850s to end up with ground temps of something like plus 4 to 7c. The 850s would almost certainly be modified upwards nearer the time as well. Furthermore, GFS over eggs snow signals in low res and on top of that it does the same with precipitation due to the grid sizes.

In reality it would probably be a rather cold day with a few wintry showers with snow up over high ground in the north and west. Pretty much an ordinary winters day.

[mackerel sky]

Groundhog day again. Zonality might get a little colder I suppose to deliver some winteryness in the west away from high ground as we enter FI. If we see the milder sectors squeezed into greens then I'm sure the Scottish Ski centres will have a fabulous season. Not much in the way for eastern parts of England as it stands, even in FI. Today was the first day this winter some frost persisted in the shade all day. And its nearly January. Piffle. Bloody weeds are still growing.

[kumquat]

Sorry, pet hate of mine when someone starts a conversation with 'wrong' :-)

In truth he is probably not far off being correct as snow would be limited to high ground in all likelihood due to considerable modification of the air mass following a long track over the Atlantic. With such a long fetch you could probably add 9 to the 850s to end up with ground temps of something like plus 4 to 7c. The 850s would almost certainly be modified upwards nearer the time as well. Furthermore, GFS over eggs snow signals in low res and on top of that it does the same with precipitation due to the grid sizes.

In reality it would probably be a rather cold day with a few wintry showers with snow up over high ground in the north and west. Pretty much an ordinary winters day.

 

 

 

 

Wrong. This is what the model shows at this time, regardless of your interpretation of it, understanding of its bias or further "over-egging" of the output run. Of course, we all realise it may be wrong but this is what the algorithm is showing in this perturbation for this time-scale. If you have suggestions to improve their computer's take on the matter, perhaps you could direct a note (or a theory paper on algorithm enhancement) to:

 

US Dept of Commerce

National Oceanic and Atmospheric Administration

National Weather Service

1325 East West Highway

Silver Spring, MD 20910

Edited December 29, 2013 by kumquat

[fergieweather]

In truth he is probably not far off being correct as snow would be limited to high ground in all likelihood due to considerable modification of the air mass following a long track over the Atlantic

Agreed but even more so (modification) given anomolously high SST's to NW of UK. But vigorous convection, yes.

[weather eater]

Agreed but even more so (modification) given anomolously high SST's to NW of UK. But vigorous convection, yes.

And let’s hope that puts it to bed.

[Bobby]

Sorry, pet hate of mine when someone starts a conversation with 'wrong' :-)In truth he is probably not far off being correct as snow would be limited to high ground in all likelihood due to considerable modification of the air mass following a long track over the Atlantic. With such a long fetch you could probably add 9 to the 850s to end up with ground temps of something like plus 4 to 7c. The 850s would almost certainly be modified upwards nearer the time as well. Furthermore, GFS over eggs snow signals in low res and on top of that it does the same with precipitation due to the grid sizes.In reality it would probably be a rather cold day with a few wintry showers with snow up over high ground in the north and west. Pretty much an ordinary winters day.

 

I agree, from experience I can be pretty confident I would not see snow from that chart. Have seen countless similar synoptics over the years (several this year) and invariably it is a tops of the mountains event, sleet/slush to lower levels at best, I'd bet a peppercorn on it. Get uppers down to -8c and we may be talking.

[Mucka]

There seems to be a few frayed nerves and tempers in here tonight, mine included.

The way some people carry on you would think deep cold and snow had been consistently forecast in here for the first half of January rather than what has actually been said.

The output is largely in keeping with expectations though I expect op runs such as GFS 18z showing wild Atlantic dominated weather out to mid month and beyond to disappear gradually over the next few days and/or be moderated while the ensembles should continue to show a cooling trend with more snow risk to low levels in the North than current modelling would indicate. (Not necessarily accumulations but I hope to see snow falling over the next two weeks at some point) 

 

GFS 18z ensembles NW England suggest things are not just a continuation of more of the same like December as some seem to be suggesting

 

http://www.meteociel.fr/cartes_obs/gens_display.php?x=240&y=40&run=18&runpara=0&type=0&ext=1

http://www.meteociel.fr/cartes_obs/gens_display.php?x=240&y=40&run=18&runpara=0&type=3&ext=1

Edited December 29, 2013 by Mucka

[Cheshire Freeze]

Ian F, there looks to be a concerning development on the NAE and EURO4 models at just a few hours out RE tomorrow windspeeds across Wales and N England. Can you shed any light on this? Looking pretty severe on the 18z runs.

 

 

Edited December 29, 2013 by CreweCold

[Matty M]

60mph sustained winds into Liverpool Bay @ midday tomorrow!

 

EURO4 model

 

@fergieweather any word on this?

 

Edited December 29, 2013 by Matty M

[bradymk]

60mph sustained winds into Liverpool Bay @ midday tomorrow!

EURO4 model

@fergieweather any word on this?

looks pretty bad, possible sting jet formation through Monday looking at both 18z NAE and EURO4, SW eng, Wales and N England Edited December 30, 2013 by bradythemole

[Jason M]

Wrong. This is what the model shows at this time, regardless of your interpretation of it, understanding of its bias or further "over-egging" of the output run. Of course, we all realise it may be wrong but this is what the algorithm is showing in this perturbation for this time-scale. If you have suggestions to improve their computer's take on the matter, perhaps you could direct a note (or a theory paper on algorithm enhancement) to:

 

US Dept of Commerce

National Oceanic and Atmospheric Administration

National Weather Service

1325 East West Highway

Silver Spring, MD 20910

Oh okay then

Wrong!

There are a lot of lurkers in this thread who will quite understandably take charts at face value. Unlike your rather rude and aggressive post I was at least discussing the model output. By all means disagree but its posts like yours that deter people from posting in here.

[The Northern Ramper]

No warnings via the met either?

[Purga]

There seems to be a few frayed nerves and tempers in here tonight, mine included.

The way some people carry on you would think deep cold and snow had been consistently forecast in here for the first half of January rather than what has actually been said.

The output is largely in keeping with expectations though I expect op runs such as GFS 18z showing wild Atlantic dominated weather out to mid month and beyond to disappear gradually over the next few days and/or be moderated while the ensembles should continue to show a cooling trend with more snow risk to low levels in the North than current modelling would indicate. (Not necessarily accumulations but I hope to see snow falling over the next two weeks at some point) 

 

GFS 18z ensembles NW England suggest things are not just a continuation of more of the same like December as some seem to be suggesting

 

http://www.meteociel.fr/cartes_obs/gens_display.php?x=240&y=40&run=18&runpara=0&type=0&ext=1

http://www.meteociel.fr/cartes_obs/gens_display.php?x=240&y=40&run=18&runpara=0&type=3&ext=1

Those ENS do look better for the NW Mucka but the ECMF for De Bilt are pretty poor

 

 

The Strat chart also looks not so good tonight

 

Let's see what tomorrow brings.