Model output discussion pm 13/01/2016

[Cloud 10]

The evolution  between the 120 hrs and 144 hrs on this evening's ECM looks a bit odd to me.

 

 

 

Would have expected a lot more energy going under the Iceland wedge of heights much like the UKMO.

[I remember Atlantic 252]

7 minutes ago, PolarWarsaw said:

Well I have to be honest. I'm a snow fan. I don't crave 10 days of frost and sunny days, I can have that in the summer for 3 months when I don't need to make the effort to wrap up. Tonight's charts are great for a cool off and they are indeed, part of what we would hope for. However, I can't help but feel like these charts, followed by a potential breakdown of sorts put us back another couple of weeks to see accumulating and/or proper snow. That's January almost gone and by that stage, you only have another month or so to get your fix. With the way things are in this country, that's a lot to fall nicely on our lap in a short space of time. 

I'm all for long Frosty and dry periods, but preferably after a nice snowfall. I'd sooner have a quick few CM's from an advancing front from the west or a 3 day toppler if it meant having snow on the ground than I would a week of Frost. 

 

 

agree with that, that's why the models have in a way downgraded, no snow on Monday now, where as I was hoping for the Atlantic to move closer, but remain cold after the snow, bit like Jan 13th 2010, Jan 18th 2013, Mar 23rd 2013, Feb 4th 2012

[Chris1986]

2 minutes ago, I remember Atlantic 252 said:

agree with that, that's why the models have in a way downgraded, no snow on Monday now, where as I was hoping for the Atlantic to move closer, but remain cold after the snow, bit like Jan 13th 2010, Jan 18th 2013, Mar 23rd 2013, Feb 4th 2012

One thing I know is nothing is set in stone. The heaviest snowfall in 2010 in the SE was due to a filiment of vorticity over France that kept feeding showers down the Thames none of which was predicted. The real development in the models will come over the next few days and hopefully the UK can hang onto the cold until a (hopefull & likely) SSW is in effect around the end of Jan / start Feb. 

[Singularity]

8 minutes ago, nick sussex said:

The differences start as early as T96 hrs over the eastern USA.

The ECM fails to develop this shortwave, the UKMO and GFS both develop this to varying degrees:

 This is NCEP's view on this from the shorter term discussions.

THE GUIDANCE ALL
AGREES IN TAKING THE ENERGY SOUTHEAST THROUGH THE SOUTHERN PLAINS
ON SAT...WITH SOME AMPLIFICATION EXPECTED. THE AMPLIFICATION OF
THIS ENERGY SHOULD FOSTER SURFACE LOW PRESSURE DEVELOPMENT OVER
THE WESTERN GULF OF MEXICO ON SAT. THE 12Z NAM/12Z CMC AND 12Z
ECMWF ARE LESS-DEFINED WITH THE LOW PRESSURE DEVELOPMENT...VERSUS
THE 12Z GFS AND 12Z UKMET WHICH HAVE STRONGER LOW PRESSURE
DEVELOPMENT OVER THE WESTERN GULF COAST REGION. CONFIDENCE IS
HIGHLY LIMITED...AND WILL PREFER TO COMPROMISE TOWARD THE ENSEMBLE
MEANS LED BY THE GEFS MEAN AND ECENS MEAN WHICH AT LEAST HAVE A
LOW CENTER THAT TENDS TO SPLIT THE WEAKER AND STRONGER MODEL CAMPS.

This low travels ene and is over the se USA by T96hrs.

The amplification or lack of in the case of the ECM is important because we want the slower upstream solution to hold back low heights from spilling too far east into the Atlantic.

 

 

 

 

The crazy thing about this is that it's not only ECM failing to develop that feature, it's JMA and GEM as well. So that throws 3 of the big guns out of the window unless of course you question NCEP's take on things. Given the background signals, I don't! 

At least the 00z ECM det. had that feature so we have some guidance from that. Other than that, it's down to the ECM ens. to help us out now.

[i luv snow]

18 minutes ago, bluearmy said:

Sorry to be a pedant but systems 'retrogress' against the usual W to E pattern 

so a high must move west to retrogress. 

Sorry to be anal

 

Being pedantic, but to retrogress is to go back to an earlier state, which could technically be E to W or W to E, N to S or S to N depending

[chris55]

4 minutes ago, Singularity said:

The crazy thing about this is that it's not only ECM failing to develop that feature, it's JMA and GEM as well. So that throws 3 of the big guns out of the window unless of course you question NCEP's take on things. Given the background signals, I don't! 

At least the 00z ECM det. had that feature so we have some guidance from that. Other than that, it's down to the ECM ens. to help us out now.

I dont see how a shortwave over the US can have any really significant influence on whether the energy just to the west of the UK goes under or over our local high pressure??

I may be totally misguided and please correct me if im wrong, but surely in this circumstance our local shortwave pattern has more clout?

[JOPRO]

People still worrying about snow not showing on the charts,as has been said umpteen times get the cold in first. I can remember  plenty of suprise snowfalls in the past for my area in 2010 and also 2013. Just chill (no pun intended!) once the cold is in the snow will follow.

[i luv snow]

3 minutes ago, JOPRO said:

People still worrying about snow not showing on the charts,as has been said umpteen times get the cold in first. I can remember  plenty of suprise snowfalls in the past for my area in 2010 and also 2013. Just chill (no pun intended!) once the cold is in the snow will follow.

Exactly, the models still haven't settled down. The cold is the most important (for now) and we don't yet know how things will evolve. There will be changes, and it could go either way but one thing we definitely can't do without is the cold! And cold is definitely what is being shown on the models...

Edited January 13, 2016 by i luv snow

[Whether Idle]

Anyone have access to the 12z ECM ens and/or 120 postage stamps and able to post them?

[Catacol]

18 minutes ago, i luv snow said:

Being pedantic, but to retrogress is to go back to an earlier state, which could technically be E to W or W to E, N to S or S to N depending

Not in weather terms... BA is correct. Go check your NOAA glossary of terms.

[nick sussex]

2 minutes ago, Whether Idle said:

Anyone have access to the 12z ECM ens and/or 120 postage stamps and able to post them?

Here you go.

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016011312!!/

[Singularity]

9 minutes ago, chris55 said:

I dont see how a shortwave over the US can have any really significant influence on whether the energy just to the west of the UK goes under or over our local high pressure??

I may be totally misguided and please correct me if im wrong, but surely in this circumstance our local shortwave pattern has more clout?

Hi Chris,

Nick explains this to some extent on the previous page, but it's to do with how the shortwave interacts with the cold air moving south in the U.S.; it essentially keeps it from escaping east to the Atlantic for an extra day or so while also dispersing it a little. 

As that cold air reaches the Atlantic trough, it triggers intense cyclogenesis and a considerably lowering of heights there, which discourages the trough disruption needed for the southern arm of the jet to be maintained. Once that shuts down, a ridge develops from the Azores while the northern arm of the jet travels 'over' (N of) the UK high and slowly pushes it south. 

If the cold air is held back and dispersed a bit, there are two benefits. The first and most likely is that the ridge has longer to assert itself NW of the UK. The second, more uncertain one is less organisation of the trough. GFS shows us that this is not a given, while UKMO seems to make the very best out of it.

 

That's my take on things, anyway.

[Ali1977]

1 minute ago, nick sussex said:

Here you go.

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016011312!!/

Quite hard to work out what's going on with those, has the ECM got plenty of support ref Atlantic inroads?

[radiohead]

12Z ECM ENS mean T168

[i luv snow]

7 minutes ago, Catacol said:

Not in weather terms... BA is correct. Go check your NOAA glossary of terms.

Well I am a linguist, so I was going by the literal meaning, rather than the meteorological one. Bad form I know. Either way, was having a laugh.

Edited January 13, 2016 by i luv snow

[Whether Idle]

Thanks Nick.  Plenty of varying options in there with a few offering an early Atlantic return.  Many blocked. Most cold, and dry.

[Ali1977]

Just now, radiohead said:

12Z ECM ENS mean T168

Mmmmm, only 1 run but not great. This is a longer cold spell than first thought though so a bonus even if it does start moving over next week....

[Mark Neal.]

@fergieweather-

W COUNTRY By weekend we see the coldest spell nationwide since March 2013: Atlantic mobility & mildness "not expected anytime soon" say UKMO

[nick sussex]

Just now, Whether Idle said:

Thanks Nick.  Plenty of varying options in there with a few offering an early Atlantic return.  Many blocked. Most cold, and dry.

There looks like some support there for the UKMO but also some pretty hideous looking ones aswell. You of course have to factor in the operationals more at this range so movement is more likely to between the big 3 operational  runs.

[phil nw.]

Just now, Mark N said:

@fergieweather-

W COUNTRY By weekend we see the coldest spell nationwide since March 2013: Atlantic mobility & mildness "not expected anytime soon" say UKMO

Which would figure if the UKMO T144hrs is the Met's favoured option Mark.

maybe cold backing west later from the undercut.Mmm.

[shotski]

2 minutes ago, Ali1977 said:

Mmmmm, only 1 run but not great. This is a longer cold spell than first thought though so a bonus even if it does start moving over next week....

Not sure if that chart, should it verify, would be a bad thing. Would tie in with back ground signals and GPs thoughts of a brief warm up and then a return to cold via a ridge to our west or north west. 

[blizzard81]

44 minutes ago, Cloud 10 said:

The evolution  between the 120 hrs and 144 hrs on this evening's ECM looks a bit odd to me.

 

 

 

Would have expected a lot more energy going under the Iceland wedge of heights much like the UKMO.

I think the reason it doesn't develop as per the ukmo is because that pesky azores high cannot resist poking it's unwanted nose into UK shores. It really is a pain in the back side winter after winter!

[tinybill]

http://www.meteociel.fr/modeles/gefs_cartes.php?code=16&ech=192&carte=&mode=0

 

looking  ito  gfs  fantasy world their a big block and the Atlantic  is going no were , poss  eastly!!!

[Whether Idle]

9 minutes ago, nick sussex said:

Here you go.

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016011312!!/

 

Just now, nick sussex said:

There looks like some support there for the UKMO but also some pretty hideous looking ones aswell. You of course have to factor in the operationals more at this range so movement is more likely to between the big 3 operational  runs.

Nick, the lesser models are going for Atlantic dominance at 120 (take a look at CMA, Brazilian) some ECM ens members also follow what I think is a false trail.  The UKMO version of events is maybe  most wished for, but it is looking isolated, if it proves correct it would further enhance a growing reputation.  We shall see.

[Man With Beard]

9 minutes ago, nick sussex said:

Here you go.

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016011312!!/

A lot of these have these have an area of high pressure between Iceland and Scotland, with troughs cutting underneath on both sides. That tells me there's a chance of upturning the whole pattern i.e. 3 days down the line we end up with a cut-off high to the north, and lower heights completely underpinning it. Now considering cold is already in place, that could be seriously wintry. It's more a dream than a forecast atm. but, having said that, it must be an option on the table.