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Model output discussion - here comes the beast!


Message added by Paul

Please only post model discussion in this thread 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

We also have a special post SSW cold spell discussion open here:
https://www.netweather.tv/forum/topic/89358-ssw-related-cold-spell-will-it-wont-it/

Thank you!

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Early guidance forewarning of next weeks weather was issued earlier on, and this has been further enhanced with extended outlooks in bulletins. AFAIK (comms not being my area) public agencies and majo

Come on those looking for the breadown before the major cold and snow has begun You will be very lucky if that is the correct word to see this in ANY winter in the rest of your lives I would sugg

Microscale detail absorbing an awful lot of attention on here, when in reality it is a waste of emotion. The macroscale pattern is now fixed - it will not change significantly now for the start of nex

Posted Images

1 hour ago, Weather of Mass Disruption said:

Surely such a chart would have as much of a chance of verifying as it does of not doing so? 

No - of course not: it is 10 days out and provides detailed indications of snow depth at a great many points across GB, Ireland and NW Europe - it has as much chance of verifying as you have of winning every Euromillions jackpot between now and then buying one ticket in each draw.

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24 minutes ago, danm said:

It's arrived in the east at that time on Monday, according to the GFS, but will push west. 

My point was that the timeframe that has been forecast for the cold air to arrive has consistently been sometime between Sunday and early Tuesday. Each run moves this around, as you'd expect. Yes, on the 6z, the cold air that does arrive on Monday isn't quite as cold as other runs (-12c into E Anglia, rather than -14c or -15c) but it is still arriving as previously forecast. 

I have been watching the forecasts from the experts on here and also the met office and it always said the last few days of the month for cold, possibly very cold to arrive. I agree with what u have said in that regard.Those are some of the best charts I have seen on here in a long time. I don’t understand how so many negative comments though are circulating in here esp for England and Wales as the charts have been consistent for very cold temps. NI and parts of Scotland are above zero during the day, dew points are closer to zero, esp around the coast and the 850’s aren’t as low. It will be interesting for the West / NW to see how we get on with this but looks great for England / Wales

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4 minutes ago, ITSY said:

People need to chill.

We will all be chilling, literally next week:cold: with cross model support for siberian cold coming around a large scandi high and across the uk..I'm also expecting snow showers to reach the east and south from sunday, continuing to increase early next week and a very wintry spell for most / all of the uk.:D

Edited by Frosty.
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Been watching models for years now, never really comment on them but been watching this easterly on the models since the start.  its amazing to watch.  Getting very excited now.  Live in eastern Northern Ireland and we generally do very well with this kind of setup.  Most memorably of recent times was the easterly in 2013 gave us 41cm and huge snowdrifts of up to 10ft to 20ft in places. Unfortunately a lot of problems to with around 150,000 losing power and lost of live stock for many farmers.

 

Only one run and I know this is far out but it does look like a nice feature! :D 

210-7UK.gif

Edited by jello
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Keep reading alot of talk that the models are not very good at picking up sea convection but that is not true, at least as far as polar westerlies are concerned and from general experience of model watching. What the models do struggle with is how far inland any convection goes and of course troughs don't usually get picked up nearer the time.

I think some are getting mislead in thinking cold uppers and warm sea temps mean snow shower machine but it does not work like that at all. Yesterday runs had everything further northwards therefore the instability is further northwards but if the scandi high gets too close to Scotland with its higher thicknesses and pressure then the atmosphere gets capped and you get grey stratuscumulus cloud with very limited convection despite upper air temps of -10. That is why some rightly are being cautious hence their dissapointment at the ECM run.

The pattern does indicate the further north you are the less room for error there is at least initially.

Still time for variations but we dont want that high to get to close as it heads westwards out of Scandinavia. 

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The excitement is building to fever pitch..just looked at the GEM 00z and next week becomes extreme..really gorging on these amazing charts from all the models!:cold-emoji::D

GEMOPEU00_144_2.png

GEMOPEU00_168_2.png

GEMOPEU00_192_2.png

GEMOPEU00_216_2.png

GEMOPEU00_240_2.png

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6 minutes ago, Frosty. said:

The excitement is building to fever pitch..just looked at the GEM 00z and next week becomes extreme..really gorging on these amazing charts from all the models!:cold-emoji::D

GEMOPEU00_144_2.png

GEMOPEU00_168_2.png

GEMOPEU00_192_2.png

GEMOPEU00_216_2.png

GEMOPEU00_240_2.png

Nice to see these charts you put on Frosty but why not add some comments as why they are so good for the members that can’t understand the charts that are posted ?

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1 hour ago, Norrance said:

Polar lows cannot be forecast at this distance in time. Perhaps someone could provide a link to the Polar Low section in  the learning area so that people can see what to look out for. One iirc is a closed circulation with no fronts.

This was once my understanding but I'm not so sure that this is necessarily the case anymore - i.e the models are now sophisticated enough to pick up/invent these small features in extended time frames.  Steve Murr, a few winters back, showed the modelled evolution of one way out beyond t70 possibly t100.  Needless to say it was a busted flush in that instance, as the predicted cold spell never materialised/got watered down but the point was demonstrated that the models do have the capability of resolving small features at extended times. The Q of whether they can do this correctly is entirely different kettle of fish.....................

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56 minutes ago, Mucka said:

Mid afternoon appraisal.

Where are we?

On the cusp of a very cold spell

Where are we going?

Into the freezer.

How long for?

At the very least for 7  days from Feb 26th but chilly before then and likely cold for a good while longer.

How much snow?

Give me the million dollars and I will answer.

But, snow showers should begin around the 27th for the E, becoming heavier and getting further inland over the next few days with potential for one or two periods of more organised snow which may get further West

Thereafter all is dependent on how the retrogression takes shape with either continued E flow with snow showers for the E and possibly more general snow attempting to push in from the SW at times or showers dying off for a time before a NE flow and bands of organised snow showers pushing SE or a slow breakdown.

The amount of snow will be dependent on how far North/South the high is, how strong the flow is, any embedded troughs for first phase, especially for the West. If you are in the East you are pretty much guaranteed lying snow at some point.

 

I would say snow showers will be experienced in the East well before Tuesday. More Sunday night onwards.

Modele UKMO - Carte prévisions

Modele UKMO - Carte prévisions

Modele UKMO - Carte prévisions

Modele UKMO - Carte prévisions

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It's really striking how cold it could be end of next week if current modelling occurs, and it is a if. If the wind picks up enough there won't be enough time to modify the air at all really, look at the 2 m temperatures in the norht sea and even east of Isle of Man. That will have some bite that's for sure.

Netweather GFS Image

 

Netweather GFS Image

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31 minutes ago, bluearmy said:

Unless we see a change on the 12z runs, the arrival of the -10c isotherm can be viewed as follows over the past 6 runs

18/2: 12z.  Tues

19/2: 00z mon night

19/2: 12z sun night

20//2: 00z sun night

20/2: 12z sun night

21/2: 00z sun night

This from ec mean. I think the main issue is that people are viewing the operationals which will not necessarily be consistent. Add to this there was a spread of faster solutions (which hasn’t verified) and the deeper cold which originally followed closely behind is now held behind the shortwave dropping sw Tuesday so is generally Wednesday now,

the likelihood of shortwave interference was well flagged up by more experienced posters. The models have hardly hid this, more especially the ops in the longer range 

 

Excellent BA.

So actually the arrival of the cold air (conducive for snow) has been ever so slightly pushed FORWARD since the runs on Sunday!

Yes the monster cold air < -15c (which IMO probably wont quite materialise by the time we get to next week, but will be close) has been *delayed/watered down due to the features you mention. But this was always likely to be the case.

So in all there is no delay to the onset of colder weather. Merely a more realistic depth of it is now starting to show in the output.

Plenty of up's & down's still to come, with regards how cold/snowy and no doubt lot's of the usual IMBY'ness run to run. But at this stage of winter/spring we should be thankful for what is progged. And that is very cold/bitterly cold from Sunday with a realistic shot at snow for ALL as next week progresses. I will take that with bells on.

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1 hour ago, Thinon said:

The GFS and ECM op squeezes the Scandi high southwards, resulting in the convective potential being pushed down into France, and a significant decrease in the severity of the cold for most parts of the UK except maybe the far South/SE.

Considering it's the GFS and ECM ops, this cannot be ruled out.

The next 24 hours will be crucial.

sorry, thats wrong. the ECM is not as good this morning, i'll give you that but the GFS shows around a week of all parts getting some significant snow and many parts getting several days of continuous snow.

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10 minutes ago, Richard David McCarthy said:

Capture9.thumb.PNG.d81faaf68a793f80f3b7320b14eeef15.PNGThis is the Latest 850hpa Temperatures GFS run at 06Z 114 hours shows the blast knocking on Eastern England and Scotland Thursday night.

 

Where is this one from?

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Some odd posts today, but each to his/her own!

Just before the 12's roll, let's have a look at the easterly in all it's glory, from the GFS 6z and ensembles (using Tableaux GEFS on Meteociel):

Ely.thumb.png.19c0a34c205ac4dde1a2046179e67a81.png

If that represents a failed easterly, my backside's a fire engine.

(To slightly misquote cricket commentator David Lloyd).

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