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Model output discussion - 7th January onwards


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Please keep this thread solely to discussing the model output. The model banter thread is available for more loosely model related chat, ramps and moans.

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So a rather long post ( Will also clip into the winter forecast thread ) However just an update on saturdays post, a large debate around models - & I took the day 6 UKMO & GFS charts to c

I assume the overnight ECM has (temporarily at least) put an end to the glass half empty stuff from some posters yesterday. I'm sure the next variation in op run will bring them back out - but if you

It's all good folks - we are about to get slammed ? Think March 2013 imprinted on the middle of winter - what's not to love ! The slider solutions are dialled in as the wave guide changes, N

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2 minutes ago, bigsnow said:

so basically not to be trusted then?

I cant say for sure but it will either be the ECM / GFS - i suppose they could use the UKMO - but the 12z was a stonker so it wouldnt be that, theres no other better model they could use because they are not in partnership with the Met Office now so mogreps not an option - so basically it can only be the models we see - and all the 12z runs are great, if it is any other model then its going to be a lesser one than the ones ive just described as they are the top 3

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Wouldn’t it be boring if the chart output was all super accurate?!

Next few days... Nerves of steel required. Emotions firmly in check. Its gonna be hairy...

Nice direction the chart output has taken today, following on from the average 00Zs. Of course, we should expect a more conservative output from the 00Zs again tomorrow, this has been the recurring theme. It would be pleasing, for once, to wake up to an absolutely cracking set. So to speak.

Nice green colours starting to emerge in all the right places, this surely only as a result of the reverse uwinds now downwelling into the troposphere. 

My take is that we are firming up on trough disruption and energy dropping NW-SE over us come early next week. Much water to pass under the bridge before an Easterly to follow gets firmed up though.

Certainly very plausible but it is currently coming about, from what I can see, by the meandering Arctic High influence and combining with moderate Atlantic ridging  (possibly as a result of MJO lag). Now the signal for some Atlantic ridging may be fairly solid but the behaviour (if not the actual presence) of pole heights is not likely to have been correctly modelled. It needs to be a player, so we don’t want to see it slipping back over the other side of the pole. If it doesn’t get involved, unlikely we will see an Easterly next week. No reason to think this will happen and who knows, maybe the even better charts are still to come!

And yes. JMA. WOW...

 

 

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3 minutes ago, Philbill said:

I have always assumed the professionals have access to much better models than we do on this forum no matter who they work for ?

The ones at the Met Office do, the ones at the BBC don't anymore.

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31 minutes ago, snowray said:

Anyone seen a chart like this before verifying? In recent years anyway?:shok:

Curtesy of the JMA.

J252-21.gif

J252-7.gif

Was the big snowfall of last year not made up of 3/4 small circulations sliding through the UK as the trough disrupted.

I distinctly remember seeing the moisture feed pumping across from Germany for hours and running round the circulations as they came through.

Probably on a smaller scale than the JMA is showing but lots of snow.

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GFS ensembles for North Midlands, for a change. Operational was a mild outlier quite clearly there. Mean looking very cold indeed around -5/-6c from D4 onwards, lots of snow symbols too.:oldsmile:

graphe_ens3.gif

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A lot of useless posts appearing again.. Yes, there are some exciting times coming up, but please, think about what you're posting.

If it's not model discussion,  then it goes HERE

Thanks folks. ?

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38 minutes ago, Ravelin said:

IMG_20190116_223414.thumb.jpg.0b5520c88bdae849d73ae4da27858f63.jpg

Just to illustrate with regards to 'uppers'. That's my back garden tonight, turned from sleety mess to snow 5pm or so and started accumulating around 8pm (ground was very wet), with uppers that should be around -5C according to 12z GFS. Now I know I'm in what might be considered a 'favourable location ' compared to most, but it still shows the uppers don't need to be ridiculous for snow to fall. 

Indeed, I don’t think the T850s are always a good guide for snow to fall , the temp at that level may seem high, but so long as it’s at least a few degrees below 0 and there is the depth of cold below ( below 128dm on 1000-850 hPa partial thickness charts good for that) and surface dew point of 0C or below to stop the snow melting as it falls, the freezing level is crucial too. Helps being as north as you are too and closer to the source with less surface moderation of the arctic flow than say southern England and the fact it’s dark helps too.

but we’ve seen many a time T850s around -5C (or maybe a degree or so higher) is adequate for frontal snow so long as surface is cold enough and dew point at or below 0C. it’s when it comes to a dry continental easterly flow with no fronts we need those lower T850s to create steep enough lapse rates over the warmer North Sea to develop convection and pick up moisture from the sea to create snowfall.

Edited by Nick F
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4 minutes ago, Nick F said:

Indeed, I don’t think the T850s are always a good guide for snow to fall , the temp at that level may seem high, but so long as it’s at least a few degrees below 0 and there is the depth of cold below and the surface dew point 0 or below to stop the snow melting as it falls, the freezing level is crucial too. Helps being as north as you are too and closer to the source with less surface moderation of the arctic flow from source than say southern England and the fact it’s dark helps too.

but we’ve seen many a time T850s around -5C (or maybe a degree or so higher) is adequate for frontal snow so long as surface is cold enough and dew point at or below 0C. it’s when it comes to a dry continental easterly flow with no fronts we need those lower T850s to create steep enough lapse rates over the warmer North Sea to develop convection and pick up moisture from the sea to create snowfall.

It can snow with T850s of just below zero. Experienced it once in the U.K. when I was in Ipswich as the zero line didn’t get over to the extreme east. 

Edited by mulzy
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11 minutes ago, snowray said:

GFS ensembles for North Midlands, for a change. Operational was a mild outlier quite clearly there. Mean looking very cold indeed around -5/-6c from D4 onwards, lots of snow symbols too.:oldsmile:

graphe_ens3.gif

Where can I find this on the site please 

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15 minutes ago, Catacol said:

Hehe - there is a first time for everything. Little story - if the mods will allow - I took a class of historians to the local Taunton archive a few years ago, and during the visit found an entry in a local church marriage register that was very odd. A very excited vicar (presumably) in the late 16th century (don't remember the exact year) had suddenly taken time to write a brief weather report in the middle of the marriage list. I can still see it now - "so much snow fell on this day that men fell and drowned in it." Have wondered ever since just how much snow must have fallen to have created an entry like this in a completely inappropriate place - and for the verb "drowned" to be used....but perhaps tells us that even the most outrageous scenario does occur from time to time!

If any model was going to be right I would favour the japenese over most, on the merit of being a leader in electrical/electronic engineering.

But I am new to model watching. Most people seem to concentrate on the big four but jma and wmc look logically more intelligent regarding an easterly lol?.

 

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2 minutes ago, MattStoke said:

Yep. Horrible run. Should be a warning to people to retain some caution.

Good advice .

We need one more day of solid runs .  There’s no such thing as a certainty and we need to see the day 6 hurdle come within day 5 .

The trough disruption over the UK is likely but the build of high pressure over the top towards Scandi isn’t yet .

 

 

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28 minutes ago, Philbill said:

I have always assumed the professionals have access to much better models than we do on this forum no matter who they work for ?

Unfortunately the BBC decided to take its business elsewhere last year just as the met office were driving a new 4WD vehicle. The BBC forecasts have to be seen to be laughed at nowadays. 

The Metoffice, Icon and Ecm look to be showing the way, as Ive said before, the ICON led the way last year with the Beast output.

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38 minutes ago, Nick F said:

Well, if the 12z NCEP / GFS blue line hugs the EPS average, then I say good chance of a cold easterly flow next week and beyond, the GFS has been at the mild end of the spread for a while until now

 

D7BE2AE2-62EA-4043-8293-E8AEE55E8A81.png

The contrast between the 18z and this mornings 00z is quite a turnaround

graphe3_1000_283_103___.gifgraphe3_1000_283_103___.gif

 

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8 minutes ago, icykev said:

If any model was going to be right I would favour the japenese over most, on the merit of being a leader in electrical/electronic engineering.

But I am new to model watching. Most people seem to concentrate on the big four but jma and wmc look logically more intelligent regarding an easterly lol?.

 

The CMA China model seems to be one thats up and coming, like JMA it has been pretty consistent with some great looking runs for next week.

cmaeu-0-144.png

cmaeu-0-168.png

cmaeu-0-240.png

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3 hours ago, chionomaniac said:

I always used to say that following an SSW that if downwelling occurred then it is a bit like a wheel of fortune spinning around the arctic where any block will set up. Never has that felt more right than following this SSW.

With weeks of downwelling still likely to occur, don’t let any run entice you in either way - always look at the bigger picture. Quite often you will see an output react to some new data and the pendulum swings far too much in the opposite direction, then when the renewed data is inputted for the next run the pendulum swings back again. Especially after an SSW.

I always think it's like a break in snooker.  You know where the balls should roll but in essence, every break is different.  The physics look simple but the outcome is surprisingly variable in snooker.

The split SSW is like the white ball and the voretex the reds.  You know the vortex will dissipate but exactly where and how remains an enigma. 

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6 minutes ago, matty40s said:

Unfortunately the BBC decided to take its business elsewhere last year just as the met office were driving a new 4WD vehicle. The BBC forecasts have to be seen to be laughed at nowadays. 

The Metoffice, Icon and Ecm look to be showing the way, as Ive said before, the ICON led the way last year with the Beast output.

The icon has been up and down lately too . The 12z run was a shocker . But luckily it’s better on the 18z run . See the 12z below . 

EB5024EA-86FA-427E-BF0D-1A0599D63B6F.png

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5 minutes ago, ICE COLD said:

The icon has been up and down lately too . The 12z run was a shocker . But luckily it’s better on the 18z run . See the 12z below . 

EB5024EA-86FA-427E-BF0D-1A0599D63B6F.png

??Doesn't look likely now to say the least lol

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54 minutes ago, snowray said:

The CMA China model seems to be one thats up and coming, like JMA it has been pretty consistent with some great looking runs for next week.

cmaeu-0-144.png

cmaeu-0-168.png

cmaeu-0-240.png

I always thought the  Asians had the best models?. They have been the most consistent in showing the easterly, let's hope the morning runs don't downgrade again. I'M not the only one dreading them I would assume ?

Edited by SLEETY
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To end the day things haven't really changed much for the 18z swingometers

For the 25th of January there are less anticyclonic members and more cold zonal but there are still some easterlies in the mix to keep things interesting. Still a really uncertain picture.

image.thumb.png.fa43160b76edb3b576ee502af8183db7.png

For the 31st of January things are perhaps even a bit of an upgrade, quite a lot of northern blocking towards the end of the month. Lets hope the 00z's aren't in a grumpy mood tomorrow morning....

image.thumb.png.fd8358d237e0b0a086cfe1600fe2d8b7.png

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The BBC News Channel weather outlook is stating, a few weeks of normal British winter weather ahead, but with next week having below normal temperatures, yet what we can see, shows the greatest likelihood to be for very cold weather next week with an easterly and the promise of more cold or very cold weather after that. I know that they no longer have the Met Office data to view, but they can still see what we are seeing so why is their forecast at odds with the current model output?  

 

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