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Model Output Discussion - Staying cold into the new year


Message added by Paul,

Please stick to discussing the model output in this thread. For more general chat , please use the winter/cold weather/snow chat, banter, moans and ramps thread

For local cold/snow and weather related chat, please head over to the Regional Area.

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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
3 minutes ago, Pembroke Dangler said:

That will feel bitter, cold east wind and temps around 2-4 feeling like -2 -4 in the wind chill brrr seasonal indeed 

Yes here's corrisponding Windchill chart.

1019774826_viewimage-2020-12-30T132745_763.thumb.png.c82f2d83e64d1b5642ad957e0e2ebae0.png

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Posted
  • Location: Woking
  • Weather Preferences: Anything unusual works for me...!
  • Location: Woking
2 hours ago, MATTWOLVES said:

Matt Hugo saying 5th of Jan looking like the big day...

 

I think this idea of “the big day”, the point of maximum interest in the charts, the “Hugo point”(!?) - might be a useful concept. Prior to the now-casting stage it’s interesting to know (or discuss!) whether the Hugo point is getting closer or receding into the distance. If the Hugo point is holding steady - or better still advancing - that’s good news for the many posters here seeking wintry hazards. My sense is that many of the failed cold spells of recent years have been hinted at through a receding Hugo point before discussions here have been swamped by disappointed reactions from posters who feel they’ve been cheated etc.

The current Hugo point appears to be January 4th. I will try to keep track of its evolution.

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Posted
  • Location: st albans
  • Location: st albans
4 minutes ago, IanT said:

I think this idea of “the big day”, the point of maximum interest in the charts, the “Hugo point”(!?) - might be a useful concept. Prior to the now-casting stage it’s interesting to know (or discuss!) whether the Hugo point is getting closer or receding into the distance. If the Hugo point is holding steady - or better still advancing - that’s good news for the many posters here seeking wintry hazards. My sense is that many of the failed cold spells of recent years have been hinted at through a receding Hugo point before discussions here have been swamped by disappointed reactions from posters who feel they’ve been cheated etc.

The current Hugo point appears to be January 4th. I will try to keep track of its evolution.

5th jan is ssw day - we will have no idea for some time after that how it will affect nw european surface conditions 

In the past, we had to wait for the reversal at the top of the models to actually begin before we began to get clearer guidance from the models - one hopes that the upgrades in the modelling over the past few years with more layers represented in the strat and higher tops to the models will mean that we don’t have to wait this time ...... 

 

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Posted
  • Location: Hertfordshire
  • Weather Preferences: SNOW AND FREEZING TEMPS
  • Location: Hertfordshire
1 minute ago, bluearmy said:

5th jan is ssw day - we will have no idea for some time after that how it will affect nw european surface conditions 

In the past, we had to wait for the reversal at the top of the models to actually begin before we began to get clearer guidance from the models - one hopes that the upgrades in the modelling over the past few years with more layers represented in the strat and higher tops to the models will mean that we don’t have to wait this time ...... 

 

Yep I remember in 2018 (BFTE) , it wasn’t actually until the reversal took place in real time that the models started to pick up the right path . (Or I could just be making that up ) .Will they pick it up quicker this time or will it be much of the same like last time ? ? 

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Posted
  • Location: Morecambe
  • Location: Morecambe
1 hour ago, Kirkcaldy Weather said:

 

The posters that have continued to go on and on and on about “lack of cold air” is nothing more than being boring at this point now having trawled through pages of the same negative tone for at least a month now, yes the 850 hpa temperatures are no BFTE but if that’s what is expected to magically appear like a Ferrari going 0-60 in 3seconds 99% of the time disappointment is going to happen as that’s abnormal level of cold for UK, I have said before we do not need that depth of cold to get snow just look at this week quite a few parts of the UK have seen what’s probably their best snow for at least 3 winters with 850 temps of between -2 to -4 of course there are other factors involved such as dewpoints which is what stopped me getting snow the other night as I was at 1C dewpoint and sleet whilst just a few miles around me others got good amounts of snow but again that’s how it goes in the UK and I was more than happy to see others enjoying it, for any new members I try to remind myself of a rhyme I made up about the dewpoints “if they ain’t 0 or below u ain’t getting snow”  

 

 

I'm sure the upper air temperature debate is boring but it's part of the model output and its worth mentioning because the easterly set up is totally different to what we have now.

You mention about snowfalls this week but they all came under slack very low thicknesses set ups so you can get away with higher upper air temperatures in that respect but if this easterly sets up then it's chalk and cheese really and you definitely need lower 850hpa temperatures than we have now.

Obviously the main difference will be increased wind speed so you get more mixing in the air right away. The 2nd being the wind is heading over a relatively warm source(north sea) so those 2 factors straight away tells me upper air temperatures have to be colder than -4 for snow to fall. I do think as it happens the 06Z GFS run is cold enough for the sunshine and snow showers set up to occur(away perhaps from right near eastern coasts) as we get a pool of -8 upper air temperatures but I know the ECM and UKMO models tend to be more conservative when it comes to 850 temperatures. For me the best scenario would be if the flow was less strong and the isobars veer a little more ENE'ly as that increases the chances surface winds on the ground will be more off shore but as it stands, surface winds will be coming in off the sea eventually and that could play a huge factor what falls out of the sky at lower levels.

As for the dry easterly, its possible the easterly could become more stable if high pressure gets too close and/or thicknesses rises which in turns puts a cap on the atmosphere and shower clouds become stratuscumulus clouds instead. The UKMO 144 hour chart looks the closest for that too happen but no doubt initially any easterly flow will be the more unstable type and hopefully it remains that way.

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

Just looked at the GEFS 6z..and my verdict is..I think coldies have a fighting chance of cold predominating well into January..unlike the last few / several years which were..let’s face it..DIRE!...of course, the GEFS isn’t the oracle, there’s other evidence from much more output but I have a good feeling this time..we may actually have a winter..for a change!!!  

Edited by Jon Snow
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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

I’ve looked into the future..well the GEFS 6z at least!..and I see wintry reloads?..now please, don’t take this as gospel..I’m not the oracle..there can be only one!!!...and it ain’t me! (Neo maybe?!)....but..I’m feeling positive, a positive energy going bravely forward into the shiny new year!

90F5BA88-AB0B-4AE9-8831-6071DC0EB368.thumb.png.9b377bbf6cab94a426e93c646f380b42.png4B132E1B-81AD-42B1-90BD-E76AC19DB4A1.thumb.png.d04a9a42cd30a6d16c3c8513e95fc955.png898CED1C-385A-4A44-BCFE-B3CC1AD95C60.jpeg.36581b46aecc628f57c8cbc283ba3bbe.jpeg
 

❄️ ⛄️ 

D1ACE5EC-BFB5-46ED-B2C2-518420B435C6.jpeg

Edited by Jon Snow
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Posted
  • Location: South Essex
  • Location: South Essex
3 minutes ago, Kirkcaldy Weather said:

Not getting involved in the responses where folk can’t see the woods for the trees, everyone entitled to their opinion that’s fair let’s see how it develops but the bit I’ve highlighted if you watched the video in my post and have understood Sea effect snow events of the past cold air + warm sea there’s your ingredients to fire the North Sea snow machine up.

Not attacking people just would rather this thread was as factual as possible especially for any new members trying to understand and learn rather than as I said earlier people wrongly banging on about lack of cold air when if anything the models show the opposite, as I say above everybody’s opinions are respected by me but yes I’m not the only one who has noted the pessimistic tone of those who again majority of the time fail to back up such negativity. I’m as big a lover of snow as you can get but I do not let that cloud the way I see the model output if it looks / mild,zonal etc I will and have shown that in the past but as things stand it’s about as far away from that as possible.

Onto the 12z runs with plenty of interest :reindeer-emoji:

That's fine, but the ramping of recent weeks wasn't exactly factual. If you feel they are wrongly pointing out a problem with a lack of cold air, engage with the argument. I really didn't like the look of this week, but not just because of the 850s because it also related to the actual 'airmass' which was always going to have issues with warm layers, DP's, Theta values etc etc. The 850s only look slightly better next week but the other factors should be much more favorable. Personally, I think the skepticism has been proved justified for many but of course others will see it differently (especially if their garden is white instead of green like mine!). People can't even agree on history let alone what's in front of them 

I'm more hopeful of some snow next week, but so far I've got what I anticipated, which is a big fat nothing!!

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

ICON has a band of precipitation moving down the country early NYD

image.thumb.png.7d2e3c553d00df4a138cca70b0996a26.png

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
10 minutes ago, Tim Bland said:

Loving the snow row increase ! London has almost all (29/30) ensembles showing snow for 4th! Never seen it that high for so many days in a row as it has for next week ! ⛄❄️

616AA019-E645-4ACE-8B6F-E2D3FE5D7136.jpeg

That may be because the maximum is now higher with the new 30 ensemble members, Tim?

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

By 126z the easterly component is being introduced along with shower enhancement from the warmer north sea 

 

image.thumb.png.70d9c675a45d3590564129938772d70a.png

image.thumb.png.7a50cebac2506633a29781af9e6c4b9e.png

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Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
5 minutes ago, Battleground Snow said:

Scandi heights even stronger at 120 on icon,

Colder uppers pulled in on an easterly.

 

iconnh-0-120 (4).png

iconnh-1-120.png

Curious at 144 on the icon as 850s seem diminished. Not to say there isn't potential further east though. 

Could really do with heights towards Greenland around about now and signs of retrogressing... 

iconnh-1-144 (1).png

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Posted
  • Location: Orpington Kent.
  • Location: Orpington Kent.
6 minutes ago, Battleground Snow said:

Scandi heights even stronger at 120 on icon,

Colder uppers pulled in on an easterly.

 

iconnh-0-120 (4).png

iconnh-1-120.png

Well hope gfs and ukm are better than the -5s & 6s shown there and if anything the uppers are warmer upstream towards Germany and Poland...

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Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
Just now, TSNWK said:

Well hope gfs and ukm are better than the -5s & 6s shown there and if anything the uppers are warmer upstream towards Germany and Poland...

Yes definitely looks milder. 

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Posted
  • Location: Coventry
  • Location: Coventry
Just now, Griff said:

Curious at 144 on the icon as 850s seem diminished. Not to say there isn't potential further east though. 

Could really do with heights towards Greenland around about now and signs of retrogressing... 

iconnh-1-144 (1).png

Yes, the high needs to stay above Scotland to stop milder air getting into the circulation, icon was one of the furthest south with the high yesterday, so let's see where the others place it.

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Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
Just now, Battleground Snow said:

Yes, the high needs to stay above Scotland to stop milder air getting into the circulation, icon was one of the furthest south with the high yesterday, so let's see where the others place it.

From a cold perspective, hopefully nothing like this icon run after 144

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Posted
  • Location: Kirklees, West Yorks
  • Weather Preferences: Winter
  • Location: Kirklees, West Yorks
4 hours ago, I remember Atlantic 252 said:

hate far away charts, but childhood setup, huge snow dump here, rain S of M4, nowadays usually just M4 south

prectypeuktopo.png

These must have been the dumpings of snow the elders use to talk about from when they were younger in 60 ands 70s. They always said the snow use to be really deep back then and we dont get systems like that above m4 these days. Well not on that scale. Only a matter of time surely ?

Edited by Snowjokes92
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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

Luckily it is the Icon and all we have to discuss .

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Posted
  • Location: Longwell Green, near Bristol
  • Weather Preferences: Storms, Gales, frost, fog & snow
  • Location: Longwell Green, near Bristol
5 minutes ago, Griff said:

Curious at 144 on the icon as 850s seem diminished. Not to say there isn't potential further east though. 

Could really do with heights towards Greenland around about now and signs of retrogressing... 

iconnh-1-144 (1).png

I assume that because a fair few models have the "easterly" next week actually bringing air sourced from SE Europe rather than the preferable NE, thus slowly mixing out the coldish upper level air we currently have over the next few days?

I imagine we won't notice much difference at the surface though, still nippy like this week.

Edited by AWD
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