Model Output Discussion - 10th Jan Onwards

[Froze were the Days]

High pressure starting to build at t240 as it turns colder

 

Just the opposite I would think with heights slowly falling and more zonal stuff to the north, mainly dry to the south. That's my take on proceedings after 240z.

[The Northern Ramper]

I think its unlikely we're going to see the stalemate as shown by the ECM,I think we will  in future model outputs show one giving way sooner. Lets hope its that troughing! this is a very complex situation for the modelling as they weigh up the block versus the Atlantic, I think this can be resolved quicker with a westwards correction and those more positive anomalies getting further nw into  eastern Greenland, that may well tip the balance but we have to factor in tonights UKMO raw output which is too far east and already past the point of no return at T144hrs.

The block is always underestimated, therefore the fact a stalemate is shown in effect makes troughing favourite.

[UV-RAY]

Are we about to see the models do a u-turn, looks like my throwing in the proverbial towel could be the key to an impending cold spell. I'll carry on writing it off.

[nick sussex]

The block is always underestimated, therefore the fact a stalemate is shown in effect makes troughing favourite.

If the block is underestimated then wouldn't that make it the winner not the troughing? Perhaps that's what you meant, but generally I prefer to see smaller highs centred over Scandi than a huge Siberian high like Feb 2012, that Feb high was too big for its own good for the UK which sat right at the periphery of the cold, although it did bring some brutally cold weather to the rest of Europe.

[nick sussex]

Are we about to see the models do a u-turn, looks like my throwing in the proverbial towel could be the key to an impending cold spell. I'll carry on writing it off.

I'll tell you tomorrow after the UKMO output has come out, I'd keep the towel handy in case that continues with its horror show!!!

[Man With Beard]

The real positive from GEFS and ECM tonight is that the search for cold is not put to bed. A return to a westerly controlled pattern is far from a done deal - the Scandi High does not go a long way between T96 and T216. ECM T144-T216 stirs memories of situations from recent years where high pressure over Scandi/Russia/E Europe just hung around, often in defiance of long-term forecasts, and split depressions that hit it in half whilst at the same time edging ever further west - Feb 2005 (which had a failed first attempt too) and Jan 2012 spring to mind, even last Jan was a little like this. So reasons to be hopeful!

Edited January 11, 2014 by rjbw

[bluearmy]

so the fat lady has exited stage left to wait in the wings ...............

The gefs members are full of interest sypnotic interest. Just need to advect some of that deeper cold west into the euro circulation. Seems to be decent x model agreement on that second system being very circular as it approaches before it begins to disrupt. If that isn't modelled correctly then we may not get those warmer uppers flooding across nw Europe. It remains fascinating.

[Nick F]

Having time this evening, for a change, to run loops through the GEFS 'pertubations' on meteociel, some interesting evolutions. Most involve the Atlantic trough disrupting against to the block over Scandi to form a cut-off low over Sern Europe. some perturbs do this quicker than the ops and other ENS members.

 

But we may still be left with strong flat upper westerly flow to the NW of the UK due to the low heights over Greenland - as shown by the 12z GFS op. However, salvation is showing in many of the perturbations in the form of a high amplitude trough exiting the east coast of N America late next week/weekend - which may help buckle the jet more favorably over the North Atlantic/Nern Europe sector. ECM headed more in that direction than GFS this evening, though still not quite enough amplification. This amplification working downstream across the Atlantic - is shown by some perturbations building heights E/NE across the UK and joining up with the Scandinavian high. With low heights/pressure remaining over Sern Europe, this draws in a cold easterly. 

 

So, 3 key areas that I'm concentrating on for us to have any hope of tapping into a cold flow from the east:

 

1. Low heights/pressure developing then remaining over Sern Europe

2. Scandi block remaining in situ (though some perturbs still develop an easterly without Scandi HP through height rises to the N and NW.)

3. Amplification in the jet working downstream from eastern N America, (preferably jet arcing N of the UK then returning SW over Scandi and Nern Europe)

 

All seems a long shot for now, but following some empirical rules, as John H may have told you about, the fat Lady may have to sing at a later date.

Edited January 11, 2014 by Nick F

[The Northern Ramper]

If the block is underestimated then wouldn't that make it the winner not the troughing? Perhaps that's what you meant, but generally I prefer to see smaller highs centred over Scandi than a huge Siberian high like Feb 2012, that Feb high was too big for its own good for the UK which sat right at the periphery of the cold, although it did bring some brutally cold weather to the rest of Europe.

I missed disrupting, I meant the trough disrupting is favourite.

[Purga]

Anyone else think we're gong to come back down to earth with a nasty zonal bump in the morning?

 

I hope not - it's just that there's a dangerous amount of optimism creeping in here tonight which is a guaranteed precursor to disaster.

[nick sussex]

Very good support for troughing to the west or over the UK and high to the ne at T120hrs on the ECM postage stamps, there is a selection of tilts to that troughing. I think we need something like member 37, that crucially has the troughing tilted negatively and positive heights have managed to get further nw towards Iceland , there are also some pretty horrid members aswell with the game over positive tilt.

 

http://www.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014011112!!/

[lassie23]

Could that nasty azores high link with the scandi high and push north, creating a strong easterly flow?

[legritter]

Ok the Fat lady is lurking out there but will she get any bigger ,if she hangs around long enough she will get bigger ,fat and frigid and hopefully turn into a sausage A GOOD Day for the models A Week in Meteorology is currently an eternity ,Some good posts tonight on the best forum .

[Gibby]

Good evening folks. Here is the report on the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Saturday January 11th 2014 taken from http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models show a ridge of High pressure crossing East over the UK overnight. Tomorrow sees a trough of low pressure with freshening Southerly winds move East into Western Britain with rain following, crossing most of the UK overnight and exiting the East by Monday morning to leave a showery SW flow with some places becoming dry. Another trough crosses East on Monday night with further brighter conditions for Tuesday before a deep trough on Wednesday brings a threat of widespread rain to all areas, heaviest in the South and West with the risk of a little snow on Northern hills.

 

GFS tonight shows a tale of two halves tonight with the first half of the output in a very unsettled mode with rain at times as areas of Low pressure stays close to or over the UK. Later in the run the Azores High makes more of an influence to the UK as it ridges closer in towards Southern Britain while maintaining an Atlantic Westerly flow with rain more confined to Northern areas.

 

The GFS Ensembles show a fairly ordinary January pattern made up of Atlantic based weather of both the wet variety and some of the drier variety too as High pressure steps closer in from the Azores later in the run. Some slightly colder weather is shown towards the middle of the run but looks hardly memorable.

 

UKMO tonight closes it's run with a Low pressure belt stretching from the NW of Britain down towards the SW of Britain with a Southerly feed of air with rain at times, heaviest in the West.

 

GEM also shows unsettled weather throughout this run with Low pressure feeding in from the Atlantic from a NW trajectory with some heavy rain at times and some strong winds at times too. Temperatures will be close to average overall with some colder air in the North at times sufficient to allow for snow at times on Northern hills.

 

NAVGEM tonight as this morning shows Low pressure further North than it's rivals with unsettled weather for all with rain at times in basically Westerly winds. Temperatures as a result would be close to or perhaps a little higher than average.

 

ECM tonight shows equally unsettled weather as the other models with a strong ridge developing in 10 days time on this operational model which would result in a colder and frosty interlude to start the Week 2.

 

The ECM 9 and 10 Day Mean Charts show a ridge of High pressure likely to be close to the UK with hints of a link with High pressure to the NE which could result in something rather drier and colder with time.

 

http://www.wetterzentrale.de/pics/Reem2161.gif

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

 

The Jet Stream shows the flow much weaker than has been the case for quite a while with it's flow taking it well South over Europe for a time. Later in the output the flow strengthens again and passes directly across the Atlantic and the UK through Week 2 though with a higher latitude over Europe around the Azores High.

 

In Summary tonight the weather remains generally unsettled and sometimes wet over the next week to 10 days. There are still signs shown that the Azores High might rescue the flooding position across the South from 10 days or so as it migrates further in towards the South of Britain later. Temperatures look like holding average values across most parts with slightly colder conditions biased towards the North at times and possibly more extensively late in the period.

[Nick F]

Could that nasty azores high link with the scandi high and push north, creating a strong easterly flow?

 

With some amplification in the jet working downstream over the N Atlantic, maybe ...

[Cloud 10]

The ECM ensemble mean and operational run certainly whistling the same tune at 168 hrs.

 

op.run..  ens..

[stodge]

Could that nasty azores high link with the scandi high and push north, creating a strong easterly flow?

 

Indeed, back in the bad old days pre-2009, one of the "hopes" for a break from the seemingly-endless zonality was for the Azores HP to ridge NE and "link" with heights over NE Europe - not that it happened too often but it was one of the "hopes" for the coldies. The problem of course is that the ridging HP often left us in an anticyclonic col - cool but a long way from snow. Not a million miles away from this:

 

http://www.meteociel.com/modeles/ecmwf/runs/2014011112/ECU1-240.GIF?11-0

 

Perhaps a wintry shower to the East or South East but not much else.

[Tim Bland]

Problem is it feels like we are back in the "bad old days" with how this winter has panned out. Good set of 12z's considering yesterday. Fingers crossed for more upgrades tommorow... You never know we might get a wintry shower out of this winter yet lol

[lassie23]

I take it there is still just too much energy to the north  preventing the azores high from moving up there? Isn't the atlantic going to become less active this wniter, it has been on the go since October, it deserves a rest.

[bobbydog]

Problem is it feels like we are back in the "bad old days" with how this winter has panned out. Good set of 12z's considering yesterday. Fingers crossed for more upgrades tommorow... You never know we might get a wintry shower out of this winter yet lol

 

we're not really in "the bad old days" though. getting snow in this country is like the lottery- the jackpot would be 1962/63.

watching the models is like watching the lottery numbers roll out. you hope but in reality, you know you're going to be at work on monday.

 

the occasional tenner would be nice though!

[Summer Sun]

ECM ensemble is showing the Azores high moving up towards the end as per the Op run if this was to happen we could be looking at something drier but colder further down the line

 

 

GFS ensemble shows the Azores getting in

 

 

Towards the end of its run we get a north westerly flow developing with the south and south west best favoured for longer dry spells once the high backs away

 

[CHANNEL LOW]

Living for many years in downtown L.A. Littlehampton West Sussex

I have always been fascinated by Channel lows.

They would on many occasions be our 'one' day winters in the seventies.

I know this is a specialist model discussion area, would anyone be interested in telling me the last recorded event, and prehaps steer me to a relevant ' department'.

Have found the topics very interesting, and i am such a slow typer that i am hoping that a channel low will one day develop.

Happy new year to you all

[nick sussex]

The ECM extended ensembles are not that exciting, its evident that as that troughing elongates it throws some less cold air nw into the flow over there, so its a case of troughing, a milder section with the deep cold held out further east, I think the ensembles see a stalemate situation for a few days. Theres an increase in easterly options towards days 8 to 10 when the troughing finally disrupts and we see a clearance of energy.

 

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

 

I think we really need to see some westwards corrections and a more favourable early tilt to the troughing to get that colder air in from the east, whatever the GFS shows on its 18hrs run its a worry that the UKMO raw output is so poor in comparison to the ECM/GFS operationals. I'd much rather have the UKMO with the ECM than the GFS in this type of set up.

[Methuselah]

Just a quick question...Does this type of 'energy' have units?

[phil nw.]

Understandably there are a number of speculative views on what may happen with the pattern as the outputs this evening promise nothing immediate in the way of cold.

I think it would be unwise to write any cold chances off beyond the next 5-6 days.The Scandinavian block seems reluctant to leave the stage clear for the fat lady.

 

However for the time being the first push has come from the west-just- but enough to leave a slow moving trough over the UK for much of next week.

 

The latest T72hrs fax a good illustration of where we will be early next week followed by the op runs to T120hrs-all with pretty similar 500hPa placements of the wave locations.

 

The Atlantic is halted but with frontal systems struggling slowly.across the UK more spells of rain with perhaps hill snow for the far north seems the unwelcome outlook.

 

As we go into next week end the ECM op at T168hrs shows if anything the block holding firm with a small patch of yellow appearing-a thickness value 552dam.Our trough starting to lift out as pressure rises from both the sw and ne.

 

so although this coming week is looking very average and rather wet at times under the stationary trough the fact that the block prevails means that the pattern can still evolve into something colder later.

A look at the ens means at T192hrs which takes us into week 2

 

with the jet profile looking weaker than for much of this Winter so far this leaves everything in the balance.

Edited January 11, 2014 by phil nw.