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Model output discussion 9th April onwards


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Posted
  • Location: Maldon, Essex
  • Location: Maldon, Essex
5 minutes ago, summer blizzard said:

The GFS run is certainly notable but more so for the rainfall it produces. It starts then simply does not stop.

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Who’s worried about fictional rain charts!

Great potential for heat and storms in the models - all good!

Edited by Djdazzle
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Posted
  • Location: Welwyn Garden City
  • Weather Preferences: Seasonal and interesting weather including summer storms and winter snow
  • Location: Welwyn Garden City
15 minutes ago, Eagle Eye said:

I'd like to make a short notice. 

PJB's post in UKWW

"After a dry and settled start to the week, Models are trending towards change in the synoptic type through the 2nd half of next week. Models are in good agreement that a building low to mid level ridge will develop over the North Sea and into the near continent early next week. At the same time a fairly sharp longwave trough is likely to extend down into the Atlantic and move east towards the British Isles. Models have trended towards a slower advance or progression of this longwave trough into the UK and as it approaches Western Europe.    

 

This delay in the progressive Atlantic pattern will allow a bubble of heat to develop over Iberia and advect NNE towards the British Isles and NW Europe. A Spanish Plume event across the East, SE and S of England and the Channel Islands seems likely through the middle of the upcoming week 19-21st June.    

 

A large plume of High Theta-W Air is advected north across Iberia, into Biscay and France and then towards the East & SE of England during Weds.  

 

There remains considerable differences in the position and strength of the longwave trough to the west of the UK by midweek and more importantly there are even greater differences between the models with respect to a shortwave trough moving NE embedded in the ascending side of the longwave which will be responsible for producing enough destabilisation to the underlying plume to allow for Thunderstorms to develop during the evening, through differential thermal advection and destabilisation of the EML covering SE England and the ability of Home Grown Evening Thunderstorms to develop as a likely loaded gun scenario develops over parts of SE England. 

 

The ECMWF is far less enthusiastic with respect to this shortwave moving NE and has an even slower progression of the longwave which eventually leads to a trough disruption over the UK & NW Europe with the continental plume and higher theta -w air remaining near or even advecting back into the UK and the SE during the end of the week. 

 

The DWD ICON model also has the shortwave moving NE but with slightly more progression it has the Thunderstorms mainly over the East & SE of England. 

 

The 00Z GFS was quite bullish about a significant shortwave trough moving NE. The model having Significant CAPE and given the Shear increasing above we can expect given this model outcome organisation of thunderstorms to occur. The ECMWF has a different shape of the trough. 

convective_overview_20210612_00_114.thumb.jpg.296810702f9a44a938bf368029652d95.jpg.3602fd68c64d2ae924deb4dd9a39b4e5.jpgsupercell_composite_20210612_00_114.thumb.jpg.37c864e3e3b0ed752ba97b5fc3b0297c.jpg.a71b61d4e46a429949f01b6876268a58.jpg

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12Z Models seen so far seem to support the growing trend towards a rather complex pattern evolution developing during the Midweek period as the Mid to lower level high migrates east and allows a longwave trough to approach the West of the UK 

 

Ingredients are there for a fairly classic Spanish Plume event to move north. The models however have various amounts of Moisture moving north and a rather different run to run set of model outcomes is probably to be expected until we reach Tuesday.  

 

Models suggest a 16-19C Theta-W 850mb WBPT plume will develop over the Spanish Plateau on Tuesday and advect steadily north during the night and into Wednesday. This Elevated Moist Layer will then lie over the SE'ern Half of England during Weds and into Weds Night.  

 

At the same time a 500mb longwave trough is set to approach Europe from the West, and at the same time a shortwave trough is likely to move NE on the foreward or ascending side of the trough, this trough aloft will increase the 500mb and 300mb vorticity or spin in the atmosphere ahead of it and increase velocity of the air upward in the ascending part of the trough.  

 

At the same time winds will increase aloft from 850mb upwards towards 300mb increasing the Deep Layer Sheer esp over parts of CS England, Midlands and into Northern England. This DLS will support any thunderstorms getting organised into possible multi cells or indeed into an MCS

 

During Wednesday very high low level heat transported north across Iberia will move into Western France with daytime maxes likely to support 36-38C and a well capped atmosphere over France under strong High Pressure and strong 850mb warm nose. However a certain amount of heat, with high 850mb Temps and 16-18C Theta-W will advect north across Biscay and at the surface a heat or surface low trough will develop across Western and then Northern France. This Thundery area of Low pressure at the surface will drift north across the Channel towards CS England . As the shortwave moves north then destabilisation of the 850mb Theta-W Plume is likely to lead to elevated EML Thunderstorms developing from around 850mb/900mb across the Channel, then moving north and further developing from the surface during Weds Night and into Thurs. Detail will be crucial nearer the time. 

 

The main question marks which exist so far are 

 

How far east will the longwave trough get before it begins to disrupt and its progress east blocked by the surge in GPH over Central Europe.  

How Active will the shortwave plume be as it moves NE towards the South of the UK on Weds afternoon and evening 

What will the thermodynamic property of the plume resemble in terms of Theta-W during Weds. Higher more widespread Theta-W values nearer to 19/20C supports more energy in the atmosphere and therefore activity 

Upper level kinematics (wind speed, wind shear etc) moving NE Across England and Wales, and how these kinematics interact and overlay the plume moving NE. Models are notoriously poor at these kind of Spanish Plume events which are very complex and therefore expect run to run oscillations over the next couple of days 

However models do seem to be trending towards a more significant interaction and a trough which may become slow moving lying NE to SW across the SE'ern half of England during the end of the week with the risk of Thunderstorms and attendant risks of Flash Floods, Lightning Strikes possibly hail and strong gusts too.   

 

An interesting week ahead. 

 

Fig 1/2/3 - ICON, GFS and ARPEGE for 18Z on Weds, clearly no agreement yet on the detail, but there is now broad agreement on the main aspects of the synoptic scale development noted above. 

 

 Paul"

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Certainly very interesting picked out a few phrases :

"Loaded gun scenario" 

Reminds me of a few lines from my favourite musical. 

Something along the lines of

"I'll load the gun, someone's got to fire the shot"

Which will now remind me of, the ingredients are there but it's too far out and we don't know whether everything will aline.

Along with the lines :

"What will the thermodynamic property of the plume resemble in terms of Theta-W during Weds." 

I'm sorry I only speak English, what this is in English, oh, I only speak Spanish then. If I need to keep my feet on the ground just remind me of the level on which I don't understand this sentence. 

GEM

2020620955_gemeuw-2-126(1).thumb.png.2ab39543b197bf487862cb84d7286cca.pnggemeuw-11-126.thumb.png.dd6fcdb30cba7d11391b09cfc6020d37.png

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Icon

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Icon has been one of the most Conservative when it comes to CAPE but I would still quite like this run. 

That's all for now, hope you all have a good evening,sorry for the low effort post. 

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Wow, get the impression from this Eagle Eye that if all the elements combine correctly there could be some serious storm activity in the week.

Just looking at the GFS12z CAPE chart for Wednesday and it is off the scale for much of France at above 3000j/kg !

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That would power some huge storms I would have thought should everything else be in order. The type of storms I remember in my younger days when storms almost the size of England would move up from France (70s,80s ? memory a bit vague) resulting in hours of storm activity with strobe lightning....

 

 

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

The really topsy turvy period of modelling goes on, as is usual with a disrupting trough against an attempted block to the east. Anything beyond Thursday still low confidence.

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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK
1 minute ago, Man Without Beard said:

The really topsy turvy period of modelling goes on, as is usual with a disrupting trough against an attempted block to the east. Anything beyond Thursday still low confidence.

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Definitely a bad bunch of 00z runs today. Pass the sick bucket please!  

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Posted
  • Location: Maldon, Essex
  • Location: Maldon, Essex
7 minutes ago, mb018538 said:

image.thumb.png.a3b5b4f3e2c1c90ce5350865b57c00f8.png

Definitely a bad bunch of 00z runs today. Pass the sick bucket please!  

I can’t believe how much they ate swinging around beyond 4 days range.

Have we really advanced in the last 10 years with modelling?

A week’s time - heatwave or cool rubbish?

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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK
4 minutes ago, Djdazzle said:

I can’t believe how much they ate swinging around beyond 4 days range.

Have we really advanced in the last 10 years with modelling?

A week’s time - heatwave or cool rubbish?

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Day 10 this morning vs last night. Today’s is about as bad as you can get with a UK trough surrounded by high pressure, including our old friend Mr Greenland high. Outlier I reckon.

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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

The one clear trend this morning is that the low pushing up from the south will likely be slow moving as opposed to your typical thundery breakdown where the low gets absorbed quickly into the jet stream.

image.thumb.gif.bdd21045113b84113c8f0eb27d60d8c9.gifimage.thumb.gif.7545594c0da0a1e54aa2afb9dfbcf5d9.gif   
 

Two days between these charts and that low has trundles a couple of hundred miles. This could be a very wet end to the week for some. Hopefully it comes with pyrotechnics.

Week 2 - I am dubious of Uber-blocking charts, something less extreme will be the result, however how settled/unsettled it will be is unclear.

Edited by Captain Shortwave
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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

Doesn't look as if we'll be experiencing anything desperately cold, but don't expect wall-to-wall blistering heat either? A situation in which subtle shifts in model-output can drastically alter the prognosis -- especially for such a small island.  

GFS 00Z:  h500slp.png     h850t850eu.png

                  h500slp.png    h850t850eu.png

                  h500slp.png    h850t850eu.png

                t850Suffolk.png    t2mSuffolk.png

So, I see no need for panic . . . but, should my toys take to the air, I'll be sure to let y'all know!  

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Posted
  • Location: Bedworth , Warwickshire , 52.475°N 1.477°W
  • Weather Preferences: Dull And Uninteresting Weather
  • Location: Bedworth , Warwickshire , 52.475°N 1.477°W

amazing what poor charts do to forum participation , well it was a short read this morning

 

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Posted
  • Location: st albans
  • Location: st albans
14 hours ago, Man Without Beard said:

Bloomin heck ... apart from @bluearmy, who saw that coming? Atlantic annihilation on the ECM between T96 and T144, back in the continental flow

Screenshot_20210612-192851.thumb.png.eb39e7197c4e48dfdefcb56b538d911b.png

 

To clarify, expecting the nwp to start throwing out certain patterns is different to knowing what will actually verify!  The outlook remains pretty fluid - certainly it’s going to become less settled ......but is that Atlantic less settled or continental less settled or even, nw euro trough unsettled ! 

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

Far too much volatility in the models from run to run at present. I'm sitting back, futile commenting on every run trying to work out the trend..

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Complete mess this morning post about 96-120hrs however both ECM and GEM at 240hrs look extremely unsettled. Would also expect the usual eastward correction for the plume later in the week. Kent clippers at next anyone? 

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
1 hour ago, damianslaw said:

Far too much volatility in the models from run to run at present. I'm sitting back, futile commenting on every run trying to work out the trend..

Comparing yesterday morning's clusters with today's around D10

ec-ens_nat_z500scenarios_2021061200_240.thumb.png.9db7f9ae3c7da6d8dfb4b96164355dec.pngec-ens_nat_z500scenarios_2021061300_240.thumb.png.51d48f53d35f42358cf02228d32cb846.png

Well there is a theme at a hemispherical level, which is Atlantic ridge / East European ridge and potential gap in between - but at a UK level, the problem is exactly where that gap will be, how developed any trough will become, and whether it becomes trapped/stalled between the ridges.

Historically just from my experience of these situations, I'd say there's a 60% chance of a low getting stuck close enough to the UK to give us cool/wet conditions, and a 40% chance of the low either escaping quickly to the north or disrupting to our SW, in which case the UK benefits from better weather and even very hot weather. I'd add too that the 60% stalled low scenario over southern England can lead to excellent conditions over Scotland - though usually the whole of the UK tends to be affected.

 

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

GFS 06Z's not a bad run, at least temperature-wise, though that small LP centred over Bournemouth, at T+99, might cause some anxiety?

h500slp.png    h850t850eu.png

h500slp.png    h850t850eu.png

h500slp.png    h850t850eu.png

h500slp.png    h850t850eu.png

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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

Wow, this won’t be popular, indeed I will be surprised if 1person likes this ..but the 6z op becomes much cooler and more unsettled from Friday..please don’t shoot the messenger, I’m just trying too be fair and balanced..not something I’m good at, apparently..even so, I feel I’ve broken the shackles of my optimism..if that makes sense?  !  ..have another drink mate..  

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Edited by Jon Snow
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Posted
  • Location: Bedworth , Warwickshire , 52.475°N 1.477°W
  • Weather Preferences: Dull And Uninteresting Weather
  • Location: Bedworth , Warwickshire , 52.475°N 1.477°W
9 minutes ago, Jon Snow said:

Wow, this won’t be popular, indeed I will be surprised if 1person likes this ..but the 6z op becomes much cooler and more unsettled from Friday..please don’t shoot the messenger, I’m just trying too be fair and balanced..not something I’m good at, apparently !  

48FB85F0-9CCA-48C9-9C3D-8CADEDFB5CF5.thumb.png.00198e495d5c529b26db4f4dc94559ba.png7733CCEC-10A2-48C2-80EC-32AE516DDB87.thumb.png.1f70e22bcf7065c807fb08c178469f69.png

never mind , I won't send you North of the Wall , can't speak for others though

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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
9 minutes ago, Gordon Webb said:

never mind , I won't send you North of the Wall , can't speak for others though

Thanks..I admire a sense of humour! ..... the white walkers are gathering, they have  just seen the 6z op!   

Edited by Jon Snow
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Posted
  • Location: Welwyn Garden City
  • Weather Preferences: Seasonal and interesting weather including summer storms and winter snow
  • Location: Welwyn Garden City
18 minutes ago, Jon Snow said:

Wow, this won’t be popular, indeed I will be surprised if 1person likes this ..but the 6z op becomes much cooler and more unsettled from Friday..please don’t shoot the messenger, I’m just trying too be fair and balanced..not something I’m good at, apparently..even so, I feel I’ve broken the shackles of my optimism..if that makes sense?  !  ..have another drink mate..  

48FB85F0-9CCA-48C9-9C3D-8CADEDFB5CF5.thumb.png.00198e495d5c529b26db4f4dc94559ba.png7733CCEC-10A2-48C2-80EC-32AE516DDB87.thumb.png.1f70e22bcf7065c807fb08c178469f69.png

Just saying it like it is JS. However i do find some of those temps being shown seem to be very low,  given that much of east/se is still under 10 degree 850s at that time.

image.thumb.png.673c89f5ffe868734e386dea9d15f1c5.png

Perhaps the ne flow undercutting is bringing the temps down but i cant believe to those sort of levels...

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
31 minutes ago, Jon Snow said:

Wow, this won’t be popular, indeed I will be surprised if 1person likes this ..but the 6z op becomes much cooler and more unsettled from Friday..please don’t shoot the messenger, I’m just trying too be fair and balanced..not something I’m good at, apparently..even so, I feel I’ve broken the shackles of my optimism..if that makes sense?  !  ..have another drink mate..  

48FB85F0-9CCA-48C9-9C3D-8CADEDFB5CF5.thumb.png.00198e495d5c529b26db4f4dc94559ba.png7733CCEC-10A2-48C2-80EC-32AE516DDB87.thumb.png.1f70e22bcf7065c807fb08c178469f69.png

I'd bet good money the maximum is not 8 or 9 degrees anywhere on Friday!

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23 hours ago, mb018538 said:

Truly awful 6z run. Less said the better!

Its a dreadful run and we are back to where we were 3 or 4 days ago.  

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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
44 minutes ago, Alderc said:

Its a dreadful run and we are back to where we were 3 or 4 days ago.  

Completely agree Alderc..but something tells me the 6z op is an outliner... ...I mean outlier...hiccup! ...I’m gonna sober up now for the 12z..promise..no booze left in da house..pity! ..that’s it, no more booze until Tesco delivery on Thursday...phew..can I survive that long. . ..very questionable..you think I’m joking?..I’m deadly serious!!!!  

Edited by Jon Snow
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Posted
  • Location: Ludlow, Shropshire
  • Weather Preferences: thunder
  • Location: Ludlow, Shropshire

Models struggling with the plume I think,   temps of 6C in Wales but 30C just over channel in France are unlikely 

If I was a betting man I would say plume of hot air wednesday/thursday with quite severe thunderstorms in places giving a cool down to 15, 17C

 

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

So, it seems the GFS operational run is not an outlier; it's just reverted to its bottom-feeding habit, is all. When the sad day (on which the operational and the mean, by some miracle, coincide) comes along, we'll all be able to give up guessing? 

t850Suffolk.png    t2mSuffolk.png

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