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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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2 minutes ago, Daniel* said:

 Pigs may fly :snowman-emoji:

I’m not disagreeing with that, however too much emphasis is being out on it, when things are from resolved. Even next week there is still much uncertainty surrounding shower distribution, snow amounts it’s likely there will be significant falls. Met Office text forecast no mention at all, of a breakdown till following week after next weekend at the earliest. As far as I’m concerned talking about a breakdown is very premature, not quite appropriate probably defeats purpose of this thread, but I sense it will be a pointless task for now. We have some fantastic looking charts, we go into the freezer within the next 48 hours the best charts, I have ever seen modelled imminent, expect unexpected.

Totally agree! GFS being over progressive (as usual). I think it will correct south over the next few runs. 

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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

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1 minute ago, Daniel* said:

 Pigs may fly :snowman-emoji:

I’m not disagreeing with that, however too much emphasis is being out on it, when things are from resolved. Even next week there is still much uncertainty surrounding shower distribution, snow amounts it’s likely there will be significant falls. Met Office text forecast no mention at all, of a breakdown till following week after next weekend at the earliest. As far as I’m concerned talking about a breakdown is very premature, not quite appropriate probably defeats purpose of this thread, but I sense it will be a pointless task for now. We have some fantastic looking charts, we go into the freezer within the next 48 hours the best charts, I have ever seen modelled imminent, expect unexpected.

I think we're looking at two different threads Daniel....lol.....I've only seen a few posts referencing a change from snowy nirvana to something different!....As you say, things are far from resolved and inevitably what will be, will be, no supercomputer algorithm can change that....For what it's worth personally I don't think any model output should be ignored regardless of what they show as one of them will probably end up predicting the correct solution....(I hope it's the ECM!) :)

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Not to be taken too seriously but EPS ens have the “mild” sector running through mainland France. 

Precipitation charts and snow depth indicate that the southwest could take a bit of a pasting. 

47173F81-37F6-48C7-8BB8-33EC2B381CF5.png

19D2ABF5-FFCC-4C2B-97B4-145513F84F7B.png

7D23A02E-0709-40CF-AB13-0DEA73FB1A9E.png

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4 minutes ago, chionomaniac said:

That was not my point. I know colder air is denser but what I said is that I don't buy the theory that cold air is hard to dislodge once in place. It may be slightly harder to displace than warmer air but if the block isn't strong enough then the mild air will come marching through. Anyway I am hoping that the low pressure is further south on the next runs.

Parameters of air (mass) resistance is a complex science. I would be under the assumption that as result of our minimal land surface area, the boundary level is more minimal in its affects to fluid flow than would otherwise be the case in a continental country. Such that as a result of minimal cold development at the surface 'warmer' air masses can easily override the cold air in place without disruption or turbulence (Ie remains laminar flow in essence), I believe this is related to something known as Reynolds Number. Anyway I do believe the macro - scale synoptics are just as important in the whole process. 

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4 minutes ago, Nick123 said:

I get your point but surely talking about a breakdown when the cold spell hasn't even started is like talking about what the lottery numbers will be next Saturday. Why can't we just talk about the here and now. This is an amazing spell of weather coming up, especially for our tiny island it's so rare to get such amazing synoptics. By the time it's here people will be so busy worrying about a breakdown they won't actually enjoy it.

You're right......IMHO talk of a breakdown is premature, but it's still valid to discuss if a model shows it...................just for info for members, for the here and now, there is the 'Short term model output thread' which is criminally underused, pop in and help Knocker and a couple others man the fort! 

 

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4 minutes ago, WINTRY WALES said:

Could it be more simple that most models are programmed to favour warm air advancing??? So when a cold block in real time seem more reluctant to budge it’s the models programming that doesn’t show the lead up correctly?? Hence why the term occurs of the cold is difficult to budge from the models getting it wrong in the short range of warm air meeting cold?

Observation certainly suggests that models overplay the progressive nature of low pressure into high pressure in winter, particularly GFS. I guess by definition this means it is the algorithms that are at fault -so yes: programming that needs to be tweaked (as we know is constantly happening as the specialists seek ever better accuracy.)

We are getting somewhat sidetracked though. For some reason a number have latched onto the GFS06 and rather magnified its significance. The balance of output sticks with the cold and 6 days is a long time in micro scale forecasting. Bring on the 12z....

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ICON at the end seems to have a battleground type scenario forming with the Azores low southerlies running up against northeasterlies moving in. This is towards Sunday mind. The low on Friday seems to be further south meaning cold(er) uppers for longer over Southern England.

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2 minutes ago, ajpoolshark said:

You're right......IMHO talk of a breakdown is premature, but it's still valid to discuss if a model shows it...................just for info for members, for the here and now, there is the 'Short term model output thread' which is criminally underused, pop in and help Knocker and a couple others man the fort! 

 

Thank you. I hope i didn't come across with any malice. I am just so excited and talking about a breakdown seems pointless with the amazing potential

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Just now, Nick123 said:

Thank you. I hope i didn't come across with any malice. I am just so excited and talking about a breakdown seems pointless with the amazing potential

not at all!......It's nice to have a chat with someone on here about something topical without it getting heated :)......( and yes, I'm excited for this coming week, it can't come soon enough!!)

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1 minute ago, snowstorm445 said:

ICON at the end seems to have a battleground type scenario forming with the Azores low southerlies running up against northeasterlies moving in. This is towards Sunday mind. The low on Friday seems to be further south meaning cold(er) uppers for longer over Southern England.

Actually, it's very close to the ECM @t144 for the same time (t132) - also this morning's GFS was close at the same time range - so we're getting some agreement for the position of the low at that range (midnight Thursday).

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1 minute ago, ajpoolshark said:

not at all!......It's nice to have a chat with someone on here about something topical without it getting heated :)......( and yes, I'm excited for this coming week, it can't come soon enough!!)

Yeah it's nice. I have been a long time lurker on this forum and recently I have started to comment a bit more. I am still learning so really don't want to offend anyone!

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I think all options are on the table for later next week. Anyone who claims otherwise is wrong- but the met office 6-30 day forecast suggests that the low pressure will encroach at a favourable angle so models that don't reflect this seem like the lower % at the moment ( these forecasts have been outstanding in the past few weeks)

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Just now, Reverse Zonality said:

Yes very little change. I think it is further south but by a pointlessly small amount of miles. Remarkable consistency, actually.

Silly question alert. If that was to verify.... it looks very snowy for the north? Or am I reading it wrong?

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1 minute ago, Summer Sun said:

Minimal change so far

gfs-0-102.thumb.png.a2a87d7c265afacf203cd324c088e9ab.pnggfs-0-1021.thumb.png.15bbf600e01b21af714786a270482561.png

Cold pool over W Ukraine/Poland is v slightly bigger and more pronounced - on this morning's ECM this moves around the base of the Scandi high and helps keep the low to the South in the end; so maybe a step in the right direction for keeping the low further South - whether GFS will manage this on this run - time will tell.

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In the end when we reach Wednesday then the coldest air is over us, so the quicker the the progress of retrograding core heights to Greenland and dropping low heights into Scandinavia the better in keeping that low near the Azores further south as it moves into Europe.

GFS/UKMO/GEM at day 5

gfs-0-120.png?12   UW120-21.GIF?24-17   gem-0-120.png?12

Once low heights move towards the NE, this will reinvigorate the Euro trough and parent low to our south will tend to move on a more easterly vector rather than towards the UK to bring milder air. We don't want the heights moving too far west of course as this is a classic west based -NAO which will allow pressure to rise over parts of Europe, a cold north easterly could become a very wet south westerly if the jet gets too far north.

Edited by Captain Shortwave
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