Model output discussion 25th Jan onwards

[bobbydog]

Funny enough I can't find a mild chart for the end of the week, SG. Please can you show where you come to this conclusion from.

 

To back me up here is the T2 temp GFS chart for Friday 12Z

 

Rtavn14417.png

 

 

Funny enough I can't find a mild chart for the end of the week, SG. Please can you show where you come to this conclusion from.

 

To back me up here is the T2 temp GFS chart for Friday

As I said, cool weather ahead of a rise in temperatures thereafter, I don't regard those 2m temperatures as anything other than cool. From Friday/Saturday the output shows an increase in temperatures from the west. Are you not seeing this?

 

maybe we should change the terminology used from "coldies" and "mildies" to "snowies" and "rainies"

 

ALL of (at the very least) todays output, shows cold. looking at the UKMO, ECM and the GFS, they ALL show cold for the duration of their forecast periods. the GFS, (which has the farthest range) has a brief period in FI where the upper air temps manage the positively tropical value of 4C. this is the only model of the three mentioned, that actually takes the uppers above zero at any point in its run.

 

during these outputs, which will change quite dramatically as we have seen, we WILL see some wintry weather, somewhere in the UK. how wintry and where, is still to be determined. as a "snowy", i'm not holding out much hope for any significant snow as realistically, the models are consistently showing (and this is a trend we can optimistically ignore) some worrying levels of rain.

the thing we CAN be optimistic about, is that with the high levels of uncertainty, the balance may tip in the favour of snow.

 

this is because at NO point are the models showing 'mild'

[CanadaAl]

Hey guys,

 

Any comment from NOAA regarding possible "over-doing" of low pressure in Atlantic and tracking post t72? I know i'm being quite hopeful here 

 

Al

[phil nw.]

In case some members missed an earlier request please post general chat and comments about about tweets, met office outlooks or similar stuff in the other threads,There are plenty to choose from folks.

More posts have had to be moved because of this.

 

Please help us to keep this thread for your own views about the model outputs only.

 

In this busy period the team havent always got time to continually move posts around so any off topic posts may be removed.

 

Please think carefully before pressing the post button to keep this thread on topic for useful reading.

[Tamara]

I think if one looks back through January and Tamars posts,she has always said that nothing spectacular would show until at least February and that this week is a bonus.

Yes that is very true, and on the basis of the trends I see, and the excellent information available on this forum and elsewhere (if one is prepared to find it and read it) then there is no reason, at this time, to change that opinion If I may say so, its gone well so far, since trying to gauge the way ahead right back in December.

 

We can't guarantee anything spectacular, none of us have an oracle, but we can give as realistic an assessment as possible of what might be achievable. For me the fun part and also most interesting part is seeing how things evolve  - whether one is right or wrong as time will always show, lots can always be learned along the way

 

@Mucka - thanks, and a very good post

Edited January 26, 2014 by Tamara תָּמָר

[Stuie]

Europe to ECM.. struggling to get any cold air from the East.

ECM to Europe.. Don`t worry I`ll smuggle some in from the West..

 

[Frosty.]

I think we...me certainly take it personally if the models don't show what I want and it's not the models fault, it's the flippin weather that decides what it's going to do. If it was our destiny to have a prolonged cold spell it would happen no matter what chopping and changing the models do in the build up so try not to get angry at the models, all they are doing is number crunching the data and have no thoughts or feelings for us..we will either be lucky or unlucky, it's all down to luck.

[bryan629]

The problem Bryan is that for an undercut a sinking low over the UK won't deliver, the interest over the last few days was for any low to disrupt to the west of the UK thereby keeping some areas with a chance of a snow as that happened because that wouldn't remove the embedded cold, yes you might well see a similar scenario played out because the models have overdone the demise of the block but in terms of a slider we needed to see a much shallower feature, that low runs east out of the west Atlantic hits the PV and blows up, this deepening pulls a lot of warmer air into the circulation, theres still a chance the models might weaken it , we'll have to wait and see but generally for a decent undercut you need to see the more elongated troughing.

 

Later on the ECM is determined to drag another load of drama out of the blocking scenario, I think coldies will soon be treated for exhaustion! Much can be made of March snow but last year was an exceptional event, we'll soon be into February so if blocking is going to deliver it needs to get a move on.

Thank you nick,

A very much a plausible explination and a very much appreciated one,  as said if this current low fills and sinks south with a block remaining solid , any deeper low moving in from the west would disrupt and force an undercut in essence catch up with the low we have at the moment.

 

aside from that isn't the pv over Canada/Greenland progged for a serious weakening soon .

[Long haul to mild]

Yes that is very true, and on the basis of the trends I see, and the excellent information available on this forum and elsewhere (if one is prepared to find it and read it) then there is no reason, at this time, to change that opinion If I may say so, its gone well so far, since trying to gauge the way ahead right back in December.

 

We can't guarantee anything spectacular, none of us have an oracle, but we can give as realistic an assessment as possible of what might be achievable. For me the fun part and also most interesting part is seeing how things evolve  - whether one is right or wrong as time will always show, lots can always be learned along the way

Wise words Tamara. It's been such a poor winter for cold and snow that it's understandable to think its never going to happen, but patience is, and has been for some while now, the watchword.

Yes, there COULD have been a better and longer cold spell coming up this week, but there still may be some wintriness around almost anywhere in the coming days to look out for

No-one is guaranteeing anything for our small island, but the long term signals have suggested for some while that if anything is going to happen, it's going to be during Feb.

Bluearmy posted earlier today about a good NH profile at day 7, and while that doesn't necessarily mean a snowy spell for the UK, it is one of the things we need in place. The block to the NE will still be there no doubt, which could be another piece of the jigsaw, although Nick Sussex rightly points out that Russian Highs can sometimes be unhelpful in getting cold here.

Yes, we do need a bit of luck but we're overdue some, and this winter, in my opinion is far from over yet. I'm not even convinced the models have next weekend nailed yet; those blocks to the NE can be very stubborn......

[damianslaw]

Whilst the three main models (ECM, UKMO and GFS) are all in agreement of the atlantic moving through on Friday/Saturday but still with a chance of a snowy breakdown for some places.. there output thereafter is far from suggestions of a return to a mild outlook. Both ECM and GFS are showing quite a similar set up i.e. the trough hitting a brick wall as it moves into the country and indications of stronger heights to our North. It looks like a slow transition to a much colder outlook, as the northern hemisphere adjusts to stronger heights over the Pole and east pacific as we enter February.

 

The theme of trough disruption remains the order of the day and a slow evolution to a more sustained colder pattern but its not going to happen overnight. I'm expecting ECM to latch onto the above in its output over the next 2-3 days and run with it. I think the models are struggling today... I notice on Sunday's they tend to perform particularly poorly...

[SMU]

Throwing in the Towel   Im surprised at you Steve, you well know that the second half of Winter is statistically more "Wintry" than the first!!!

 

not really throwing in the towel just being realistic with whats showing after things have developed in the last 24 hours-

 

regards

Steve

[nick sussex]

The ECM postage stamps have very good support for a deep low pressure near the UK at T120hrs:

 

http://www.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014012612!!/

 

The ECM mean shows the PV chunk still there over Canada, troughing near the UK and blocking to the ne and east so overall supportive of the operational run.

 

You can see from the ECM short De Bilt ensembles the operational run in the middle generally:

 

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

Edited January 26, 2014 by nick sussex

[Summer Sun]

After a short cold snap its back to more wind and rain from next weekend according to the ECM ensemble, towards the end of its run we start and see some less cold 850's approaching the south west

 

 

The low at t120 is shown to be around 980mb according to the ensemble

 

 

The Op has it around 950mb I think

 

Edited January 26, 2014 by Summer Sun

[Gibby]

Good evening. Here is the report on today's midday outputs from the NWP for today Sunday January 26th 2014 and taken from my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models show a deep depression close to NW Scotland with a cold and showery WNW flow over the UK. The showers will be heavy and wintry at times with hail, thunder, sleet and snow all possible almost anywhere but more likely near western coasts and hills. Through the first half of the week the parent Low pressure slips South down the Western side of the UK and then away to the South maintaining the unsettled and sometimes wet weather with temperatures on the low side of average. Pressure then builds strongly from Scandinavia briefly over Thursday and into Friday with drier and cold weather on an Easterly breeze which falls light later in the week allowing frost at night.

 

GFS then takes us out of the week and into the weekend showing the first of yet another series of deep depressions, many ending up over the UK with the resultant wet and windy conditions keeping things over the flood stricken parts of the UK very depressing indeed. Temperatures remain close to normal but it will feel chilly at times and there will continue to be some snowfall on higher ground at times, especially in the North.

 

The GFS Ensembles show a chillier period this week as the Low pressure responsible slips South of the UK. It then turns very Atlantic dominated again as Low pressure brings milder weather with periods of rain and showers in strong winds and temperatures returning to close to or slightly above average values later.

 

UKMO shows the start of next weekend with a Low pressure trough having cleared to the East of the UK with a spell of rain having cleared to the East followed by NW winds and wintry showers across the North and west later.

 

GEM shows a reversion back to Atlantic based weather next weekend with periods of rain and strong winds moving East and NE across the UK towards the end of the run replacing the rather chilly conditions of this week with temperatures rather closer to average.

 

NAVGEM shows the only chance of colder air in association with a block to the East offering some resistance to the Atlantic onslaught next weekend as Low pressure areas disrupt and weaken in situ over the UK with rain bearing fronts slowing and stalling across the UK with rain and snow in places to begin with before all areas away from the NE become less cold and wet as a deep depression lies to the west of Ireland.

 

ECM tonight also shows the Atlantic winning out next weekend as a front crosses East with rain then wintry showers. Then as we move into the new week the weather remains and if anything becomes more unsettled as Low pressure becomes ensconced across the UK once more.

 

The ECM 9 and 10 Day Mean Charts tonight indicate a bias towards Low pressure to be most likely to be situated to the west of Scotland with SW winds and unstable air across the UK with rain and showers across ll areas and temperatures back up to average levels with any cold from the block to the East back to the other side of the North Sea.

 

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

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

 

The Jet Stream shows the flow maintaining it's current trajectory for next week to the South of the UK. The trend in the latter stages of the output tonight is for the flow to strengthen yet again and shift position to cross Southern Britain in Week 2.

 

In Summary tonight the weather is going to become rather chilly this week but apart from some scattered snow flurries there seems little chance of any widespread snowfall anywhere. However, it will feel more seasonal for a time as winds shift easterly for a short time after midweek. Later in the period the Atlantic regains supremacy with most models showing an easy victory for the Atlantic with little prospect of anything other than transient snowfall away from the high ground of the North and NE before temperatures return nearer to average and what's more important in my estimation a very real possibility of much more rainfall to add further misery to those areas afflicted by floods.

[Severe Siberian icy blast]

not really throwing in the towel just being realistic with whats showing after things have developed in the last 24 hours- regardsSteve

The thing is nothing mate nothing is written on the wall yet , trough disruption looks the way forward but things are so volatile I wouldn't be surprised to see another change on the way

[Captain Shortwave]

Well with the shortwave upstream running over the top of the Azores high and engaging the cold polar air, it pretty much kills the potential trough disruption which looked pretty good for the end of this week. Things might change but it may be too far to reign things back in our favour.

On the other hand the high to the north east will remain and as seem over the coming week, it's influence can push westwards with us under an easterly for a couple of days, it can happen again or even a slider beyond around day 5.

I have to admit to feeling very weary and tired with the current set up and the many near misses we have seen, but we have to soldier on and with the strat warming coming into play soon, we might see some positive changes in the near future. For now we remain in possibly the most frustrating holding pattern ever in the history of the universe 

Ok the last sentence may be a little OTT, but you get the gist. 

Oh and enjoy the snow if any of you see any tonight

Edited January 26, 2014 by Captain shortwave

[bluearmy]

an early spot and it may be gone in the morning but the beast stirs over russia and by day 10, the 850 spreads have it approaching poland. we, on the other hand can look forward to a developing shallow mid atlantic trough which will sink the jet further south as the azores ridge pulls west. there is a dynamic whereby the trough to our west sinks se and throws up waa (see day 10 ecm op for a crude representation) which rebuilds the scandi ridge and hopefully draws the russian high west (as the jet drives into europe and begins to advect the flow from east to west.  

 

whilst its disappointing to see the battle lost re this upcoming potential period, there are indeed signs of something to follow and whilst the ens means probably show the atlantic blasting through, i doubt that what will happen.

[IDO]

We have only reached agreement on the second slider failing. Still much uncertainty as to what happens afterwards and how quickly the Atlantic moves in.

GEFS are all over the place with respect to post non-slider, and no cross-model clarity either.

As usual ECM the better FI charts, even though that is another 10 days away and therefore chances for it to all go belly up again.

[Geordiesnow]

Well i think people have finally started to realise that the output was not as snowy as some might of expected to be and that the trend has been consistent really and well no surprises from me with the way the output is heading giving the winter so far. 

 

You do wonder where a sustained snowy set up will come from tbh, with the PV in the Arctic all broken up then any Northerly will be diluted and it has to be sustained to prove significant one would of thought and even to the East, any significant cold is a long way off really so a pretty depressing outlook it has to be said and one that kind of summed this poor winter up for cold really. 

 

There might be a little bit of snow this week but the convective window is so brief you blink and you miss it and yes it might not turn mild but its going to turn wetter again and quite frankly, I think everyone is sick of the rain now and it does no help for the saturated ground.

[damianslaw]

Sometimes - well all times I think it pays to look at the wider picture and background signals to get a feel for how things may pan out rather than getting hung up on model run to model run, particularly when a pattern change upstream is taking place - as projected to happen now (albeit a rather slow affair... the very start is already under way..)

 

There are a number of factors which longer term are very good ingredients for a colder less atlantic influenced outlook.

 

These are -

 

1. Development of a strong robust NE pacific high which importantly in combination with strong heights over Russia will maintain a split PV and enable heights to build over the Pole. These heights will put pressure on the PV sinking it further westwards more towards the north of Canada as opposed to NE Canada/West Greenland.

2. As a result of the above, a major change in the pattern over USA/Canada with a trough over western parts and consequently strong heights building over the east - meaning less energy coming off the eastern seaboard.

3. An azores high which is expected to migrate away to the southwest which in turn will pull the Jetstream further southwards.

4. The effects of the above will no doubt cause the following to happen:

 

1. The atlantic trough to back further west aiding warm air advection into scandi promoting height rises over Svalbard region.

2. The effect of the above will force the trough on a SE path into Europe (trough disruption) and consequently conditions will be ripe for heights to build to our east/ne in a position far more favourable to a colder pattern here.

[Man With Beard]

After a short cold snap its back to more wind and rain from next weekend according to the ECM ensemble, towards the end of its run we start and see some less cold 850's approaching the south west

 

 

The low at t120 is shown to be around 980mb according to the ensemble

 

 

The Op has it around 950mb I think

 

On the subject of ECM ensembles, this represents a big turnaround from two days ago when almost all members wanted a huge slider and stronger eastern heights for the same day. I've already highlighted big sudden flips in the ensembles at a much nearer time. Clustering on the ECM ens, clearly, has been of little help in the past few weeks.

[winterof79]

There is always the 00zs 

http://www.knmi.nl/exp/pluim/Data/pluim_06260_0_12_60.png?1390770946664

 

But as i type a blizzard outside??? Who knows what this week has in store.

Edited January 26, 2014 by winterof79

[Cloud 10]

Having a look back at the 500mb height anomalies for the Northern hemisphere so far this

winter at least reveals things are heading in the right direction,with the polar vortex declining

and blocking becoming prevalent over the polar regions.

 

December..  January so far..

 

I wonder what the February composite will look like?

[Snow Grain]

No, you actually said a 'transition from cool to mild' at the end of the week. Again, I politely request to show where on the models this is so. The GFS, which shows the T2 temps, has no double figures leading into next Monday other than the Scilly Isles with the vast majority of the country no more than 5-6ºC max. And please could you put your location in your avatar, thanks.

I know emotions can get high in here but all I have done is give my opinion on how things will play out this week by looking at the current outlook models. This also means that I may not agree on the projected 2m temperature charts, I believe the temperatures will be 2-3 degrees higher unless subsequent model outputs change of course. You seem to be insisting that the current output is set in stone but we all know that model accuracy is not that great.As far as the temperatures go, I do feel that they are not projected to be anything other than cool, maybe i have spent too long in Alberta! Anyway back to the models, turning cooler but feeling cold compared to what you have been used to this winter, turning milder by the end of the week. This is based on today's output from the main models which show a short spell of easterlies replaced at the end of the week by Atlantic driven weather. Although an undercut low would help, the real issue is that the hp to the northeast is just not extending west enough to have enough influence on the UK weather apart from stalling rain bearing fronts close by.

[bluearmy]

the extended ecm ens show that push west of the lower uppers not making it further west than poland. will be interesting to see on the graphs later how many really cold runs made it to warsaw and if so, they shouldn't really show in berlin.  infact the 11/15 day ens continue to promote the idea that we could see our developing mid atlantic trough create a sceuro ridge of sorts which will not be a welcome scenario.

[SMU]

Remember the deep that low shown today is a result of phasing & timing- IE the 2 atlantic system phase together- should the timing not occur optimism will be improved.

 

The ECM has heigher heights lingering around for a fair while, however we need to get some cold air back into the block from Siberia again as a top up

 

18z slightly more south with the low in the atlantic at 72- may help

 

S

Edited January 26, 2014 by Steve Murr