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Model Output Discussion 01/09/17


phil nw.

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

So looks unlikely now we will get anything resembling last nights 18z but the models may well be underplaying the trough disruption as it pushes east over the UK.

That would allow for some wintry weather in the North, especially over high ground for a while, not too exciting but barring a big turnaround back to cold it is at least something seasonal.

The next window of opportunity comes once the trough has pushed to our East in the final days of November. ECM ensembles have small  cluster going cold toward end of November while GFS has cooling trend for the same period.

ensemble-tt6-london.gif

If this chance has truly gone then let's hope to see support grow for colder weather end of Nov and early Dec.

 

Edited by Mucka
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Posted
  • Location: NR Worthing SE Coast
  • Location: NR Worthing SE Coast
7 hours ago, damianslaw said:

What a difference an evening makes, this thread was alive this time yesterday, and now we have a GFS 18z showing the complete opposite, its not called the crazy run for anything, but still people seem to get hung up on it - its either the saviour or the enemy for some. As I said expect further twists and turns and treat all models with much room for error within the very short-timescale at present - we have an unusual synoptic set up, that the models are going to struggle to get to grips with. Indeed the reliable timeframe over the next week or so, may only be 72 HOURS tops.. making any medium term forecasting fraught with difficulty. (I feel I might need to keep repeating myself over the days ahead - some never learn..).

very true just compare the difference between the ecm and gfs at 72 hours and 96 hours again this morning.maybe nothing is still resolved yet.

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Posted
  • Location: Camborne
  • Location: Camborne

The front that was hanging around in southern parts yesterday has cleared away and today will be fine and quite chilly in most of the UK after a frosty start.The exception will be the west and north of Scotland which is still under the influence of the low to the north which is tracking east to the Norwegian basin, Here gales, perhaps severe, will persist with squally showers of snow on the higher ground. Tonight similar that the winds and showers will abate and become far less frequent whilst cloud will move in from the west in the south of England

PPVA89.thumb.gif.b95dc8b51848eda0a754bf19353f3f5b.gifPPVE89.thumb.gif.4155364c9f1125eeaad9fef54e47cf81.gifPPVG89.thumb.gif.3e9e18a796cfbbe671ab434ee9891df4.gif

So to this morning's gfs. Saturday a quiet day under the ridge but some cloud and rain in the south and Sunday much of the same but by 18 a surface low that has broke away from the main upper trough in the western Atlantic and is 994mn south of Iceland with the associated front and rain just impacting north west Scotland From this point it runs quickly easy across Scotland, where it could well dump some snow on the high ground, and by 12 Monday is in the North Sea.

gfs_ptype_slp_eur3_12.thumb.png.597ca5c442982c81876390b123e9e720.pnggfs_ptype_slp_eur3_15.thumb.png.215e43bc831fec085c16910002fdea48.png

Meanwhile another frontal disturbance has formed in the main trough to the west and has tracked quickly east to impact Scotland by 06 Tuesday whilst at the same time a trough has slipped south east of Greenland to join the fray dragging down the colder air with it. Worth a closer look I feel as it illustrates quite well I feel the energy flows (that i previously wittered about vis the anomalies) and the sharp delineation between the cold/warm air.

gfs_ptype_slp_eur3_18.thumb.png.c2b94fd181e108ca03b34286d1b39a0c.pnggfs_z500a_natl_18.thumb.png.6eb49f62fd64fe843c4d1ae5b763e68c.pnggfs_t850a_natl_18.thumb.png.c5ff5cf141b6045f64ca8241126ea530.png

The shallow low moves quickly east whilst the main trough to the west moves in a similar direction and by 12 Wednesday there is a complex area of low pressure just to the west of the UK and more fronts have pushes NE into Scotland  There is a lot going on in this main trough including some fairly rapid cyclogenesis and 12 hours later an intense low 965mb is adjacent to the Hebrides with the UK in a strong, squally, south westerly airstream with gales in the west and possible severe gales in Scotland and N. Ireland. It follows from this that the colder air to the north has made no further ingress south with the energy flow from the eastern seaboard east having the upper hand.

gfs_ptype_slp_eur3_23.thumb.png.13f1abce5f47b25531ed9ddb46c2e18b.pnggfs_ptype_slp_eur3_25.thumb.png.f206a16520a27f4b00e3e9d2b485ab14.pnggfs_uv500_natl_23.thumb.png.ab63fe3b81e733412b2fc60cad7c011a.png

There is absolutely no point in going into further detail from this point as a) it is obviously subject to change and b) there are too many little lows floating about. Suffice it to say  the intense low clears quickly east leaving the complex area in situ to the west with more fronts encroaching on Friday. So in summation. Becoming very unsettled next week with gales, perhaps severe, and some wintry weather in Scotland.

gfs_ptype_slp_eur3_31.png

Edited by knocker
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Posted
  • Location: Dipton, Nr Consett, Co.Durham, 250m, 777ft asl
  • Weather Preferences: Anything but boringly hot
  • Location: Dipton, Nr Consett, Co.Durham, 250m, 777ft asl

B'jesus I can see why there's not much commentary on the GFS 00z. Is definitely a milder run, not quite the washout that mild means at this time of year and still no autumnal storms to speak of so that's one bonus.

The NH profile is still showing lots of blocking at our islands latitude but just happens to be at locations too far west and east to help us. But think of those Europeas touching lucky this time round because we aren't. Fact is blocking is readily available at our latitudes so early on this year and the higher pressure oop north will keep things in similar latitudes.

The fact the chase is on so early again, is a bonus, after all the hunt is nearly as good as hitting the target.

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Posted
  • Location: Isle Of Lewis
  • Weather Preferences: Wild!
  • Location: Isle Of Lewis

I still cant buy into an atlantic onslaught with such a huge area of greenie high. It is like the GFS has a light switch between stalling cyclonic conditions in the atlantic and then suddenly they evolve and move in eastwards over uk before turning westwards again. I just cant see that happening. 

This will be a good test for the models. Might be worth analysing which one was closer by this time next week. I imagine it will be ECM.

Longer term synoptics and teleconnections look good for winter... if you like snow. 

 

 

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Posted
  • Location: Camborne
  • Location: Camborne

The ecm is still tracking the front on Monday a tad further south, Liverpool to the Wash at 06, so still the possibility of snow along the northern edge over high ground I would have thought. After that a front and strong winds impact the north west late Tuesday leading to a very grotty 24-36 hours as an intense low crosses the UK bringing heavy rain and severe gales in places This clears to the north east by 12 Thursday leaving, surprise, surprise, a complex area of low pressure to the W/SW although the colder air has moved closer

ecm_mslp_uv850_natl_6.thumb.png.95d93a187b3f5b4a2dc8ad10df2f1df8.pngecm_mslp_uv850_natl_7.thumb.png.36b997e2bb3884ef7350ca92f4ed2932.pngecm_mslp_uv850_natl_8.thumb.png.909b41e2f3dbf8eb8bac59683b5f9290.png

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Posted
  • Location: st albans
  • Location: st albans
23 minutes ago, Steve Murr said:

Morning all

 

A frustrating period of model watching especially with a bit block over the pole so keep the interest!

I noticed a lot of talk about the strat decoupling working its was out & - few mild westerly decembers filtering into the mix

its worth keeping an eye on this- A significant negative anomaly in the higher strat this morning on the GFS suite- first time ive seen this !!!

IMG_1231.thumb.PNG.ba82061a438301e6070b8c44881dfe50.PNG

Ukmo offers a window at day 6 upstream - I wonder if the day 7 chart shows if the ridge builds between to derail the train of systems. 

As far as the strat is concerned, there is no evidence that the current uptick in flow will be sustained as it downwells and Berlin charts are rock solid that they begin to pull back into the mid upper strat in the 6/10 day period. Just assuming that x+y =z really isn't a scientific approach. 

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25 minutes ago, Steve Murr said:

Morning all

 

A frustrating period of model watching especially with a bit block over the pole so keep the interest!

I noticed a lot of talk about the strat decoupling working its was out & - few mild westerly decembers filtering into the mix

its worth keeping an eye on this- A significant negative anomaly in the higher strat this morning on the GFS suite- first time ive seen this !!!

IMG_1231.thumb.PNG.ba82061a438301e6070b8c44881dfe50.PNG

sorry to ask but can somebody explain what this means and weather its a good thing or bad thing and why etc.. interested to learn. thank you.

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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

To call the Gfs 00z mild wouldn't be doing it justice..it's warm, it's tropical, it's a blowtorch similar to December 2015 when we last had a bumper crop of december daffodils, hope it verifies! ;)reverse psychology has worked before.....:crazy::D

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p1020680.jpg

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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk

Cross model agreement seriously mild unsettled.

I knew last night's towel throwing was worth it.

Anyway I get another one.

Really hope that European heights buggers of.

It be ok if euro heights makes its self useful but unlikely with that much cyclonic activity to our east and southeast.

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Models remain pretty similar to last night on the whole..

GFS shows a torch pumping up mild south westerlies from the Tropics. 

Euro and UKMO do progress the trough east and the Euro looks like the next attempt might have a better chance towards day 10. 

ECH1-216.GIF

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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire

Nice to see the valium hasn't been tapped into yet on this forum. I thought I would point out some positives from the output this morning and cast aside the negatives. Firstly, the ecm day 9 and 10 charts this morning are quite a significant improvement on last night's. The gfs ensembles show quite a marked cooling post day 10 and apparently the latest ec46 is still showing encouraging signs as we progress through December. 

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Posted
  • Location: Camborne
  • Location: Camborne

The UKMO has the deep low pretty much as the ecm at T144 which would portend severe gales  Obviously the detail will change in the interim but a watch needs to kept on the chance of some severe gales next week

GZ_D5_PN_144_0000.thumb.gif.2c1e3ddbe46e5fd8de0003629edd2548.gif

 

Edited by knocker
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Posted
  • Location: Horsham, West sussex, 52m asl
  • Location: Horsham, West sussex, 52m asl
16 minutes ago, More Snow said:

sorry to ask but can somebody explain what this means and weather its a good thing or bad thing and why etc.. interested to learn. thank you.

it's someting i've been keeping an eye out for over the past week or so. first signs of all this blocking we are seeing, and vortex disruption, making its way upwards into the strat. could come to nothing but...

gfsnh-10-384-2.thumb.png.2242887eccd1f239eddf336c1a010a9f.png

in the ideal world, the trop vortex intensifies (as modelled by the GFS) the strat disrupts (SSW) and what goes up must come down.....

its too early to say if we are seeing the beginnings of a warming but the sign has appeared and the strat is less prone to wild swings in modelling. keep watching...

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
4 minutes ago, knocker said:

The UKMO has the deep low pretty much as the ecm at T144 which would portend severe gales  Obviously the detail will change in the interim but a watch needs to kept on the chance of some severe gales next week

GZ_D5_PN_144_0000.thumb.gif.2c1e3ddbe46e5fd8de0003629edd2548.gif

 

That looks quite nasty, batten down the hatches if thats accurate.

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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

ecmslp.096.png

this at t96, I think not a bad position at all with room for both improvement and deterioration 

 

BFTP

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Posted
  • Location: Near King's Lynn 13.68m ASL
  • Weather Preferences: Hoar Frost, Snow, Misty Autumn mornings
  • Location: Near King's Lynn 13.68m ASL
54 minutes ago, More Snow said:

sorry to ask but can somebody explain what this means and weather its a good thing or bad thing and why etc.. interested to learn. thank you.

As bobbydog says, it's a good thing if you are looking for signs that the stratospheric vortex is becoming disrupted. However, as Andrej of this parish is often pointing out, the GEFS have a significant negative bias at those levels.

Edited by Yarmy
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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

On the individual EC members this morning, we at last have agreement on the shortwave with all 51 members successfully getting the first two Atlantic troughs through to the UK - and therefore the risk of cold getting to the south is low (still knife-edge in the far north).

Perhaps 10-15% of members cause enough separation in the Atlantic by D8/D9 to allow a temporary back-edge northerly ... but of course that means 80-90% don't.

West based -NAO it is, then.

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Posted
  • Location: NR Worthing SE Coast
  • Location: NR Worthing SE Coast
36 minutes ago, BLAST FROM THE PAST said:

ecmslp.096.png

this at t96, I think not a bad position at all with room for both improvement and deterioration 

 

BFTP

yes nice chart.it be interesting to see how this finally pans out next week.I know the usual suspects in here are writing off the chance of the cold air winning out,but anything after 4 days is an awful long Time in model watching as we know.

 

Definitely the final outcome is not nailed on at all yet.

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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK

This mornings ECM at T96 has a stronger cold block than shown by GFS and UKMO in place over Northern and Central parts of Britain. Looking at the consistent short range ARPOPEU model , appears to go with ECM. A lot of talk on here about the effect of short waves in the medium term forecast models holding back cold penetration into your part of the world. In this case the reverse could still happen as the warmer air mass meets the cold block in place. 700mb charts show a deepening cold pool to develop between Iceland and NW Britain. Any short waves that develop along the boundary of the increasingly cold upper air and the mild surface flow could advance the cold further south and west.. Still a lot to be decided even in the shorter term model range. Not all interest lost yet for cold lover.

 C

ECMOPEU00_96_2.png

Edited by carinthian
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Posted
  • Location: Solihull, West Midlands. - 131 m asl
  • Weather Preferences: Sun, Snow and Storms
  • Location: Solihull, West Midlands. - 131 m asl
9 minutes ago, carinthian said:

This mornings ECM at T96 has a stronger cold block than shown by GFS and UKMO in place over Northern and Central parts of Britain. Looking at the consistent short range ARPOPEU model , appears to go with ECM. A lot of talk on here about the effect of short waves in the medium term forecast models holding back cold penetration into your part of the world. In this case the reverse could still happen as the warmer air mass meets the cold block in place. 700mb charts show a deepening cold pool to develop between Iceland and NW Britain. Any short waves that develop along the boundary of the increasingly cold upper air and the mild surface flow could advance the cold further south and west.. Still a lot to be decided even in the shorter term model range. Not all interest lost yet for cold lover.

 C

ECMOPEU00_96_2.png

Yep C..

This chart demonstrates what would happen if (heaven forbid) the GFS is misreading the energy leaving the US and blowing up the lows too much.

We all know that the GFS is not immune from these characteristics.

MIA 

 

Edited by Midlands Ice Age
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Posted
  • Location: Crymych, Pembrokeshire. 150m asl
  • Weather Preferences: Extremes of all kinds...
  • Location: Crymych, Pembrokeshire. 150m asl

Big four all suggesting some wild north Atlantic weather at +144-150....

  image.thumb.png.563088ae1d233914ab981ca63e5a14c1.png   image.thumb.gif.4102f9c296901f0d7abd2a2dd6cc86aa.gif

image.thumb.gif.ee89d502a7239400ced6b5ddc3b07810.gif . image.thumb.png.01c251e59a9666e94a68cb327e43c882.png

This might go one of two ways - either they all shift a little further south east in which case there's a lot of colder air around which could be drawn our way; or further north and we get mild, wet and very windy.

Either way I'm glad I'm not booked on the Rosslare ferry on the 22nd.... :bad:

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

A mild week coming up next week later in week somewhere around the wash could hit 18c

1.thumb.png.6b71540afcaa19f7c745eb860ecc4ee9.png2.thumb.png.d7bfffe45115064e1c1aa479284aa4b2.png

3.thumb.png.6e67cdaea9144eff40df28f6ffd11678.png4.thumb.png.725cd0c5067aeefee22785f6ec3cc2ad.png

The overall November record is 22.4c maybe some daily records could go if Thursday's chart was right?

 

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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
11 minutes ago, Summer Sun said:

A mild week coming up next week later in week somewhere around the wash could hit 18c

1.thumb.png.6b71540afcaa19f7c745eb860ecc4ee9.png2.thumb.png.d7bfffe45115064e1c1aa479284aa4b2.png

3.thumb.png.6e67cdaea9144eff40df28f6ffd11678.png4.thumb.png.725cd0c5067aeefee22785f6ec3cc2ad.png

The overall November record is 22.4c maybe some daily records could go if Thursday's chart was right?

 

Yes Gavin some late November BBQ's if the Gfs 00z verifies..Barmy  and Balmy indeed!:shok::crazy:

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