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Model Output Discussion - Into November 2019


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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
7 minutes ago, mb018538 said:

I like how people are talking as though we are in the depths of winter! Easterlies aren’t particularly cold yet. The sea is still warm. It’ll take something monumental to get very cold conditions in what is technically still autumn. 

That is my point in my last post, a half baked effort won't cut it, so you have to minimise sea moderation, so a siberian blast is the only way to get non-marginal guaranteed heavy snow.

Edited by feb1991blizzard
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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .
11 minutes ago, CreweCold said:

Day 10 now takes us towards the date where more widespread low level snow is possible so we need to pray things fall into place for us. That ECM relies on a LOT of things going in our favour to arrive at that day 10 chart. 

True . And generally in the UK if it can go wrong it does . I’m taking a glass half full approach, the background signals are good , let’s hope that transfers to the outputs .

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Posted
  • Location: Medlock Valley, Oldham, 103 metres/337 feet ASL
  • Weather Preferences: Cold, snow, thunderstorms, warm summers not too hot.
  • Location: Medlock Valley, Oldham, 103 metres/337 feet ASL
14 minutes ago, mb018538 said:

I like how people are talking as though we are in the depths of winter! Easterlies aren’t particularly cold yet. The sea is still warm. It’ll take something monumental to get very cold conditions in what is technically still autumn. 

Very cold? Depths of Winter? No one's mentioned anything like that. We're just warming up *mind the pun*. A relatively warm North Sea is good for us - it generates convection as cold air from the east travels over it. Think snow machine. Another thing..... You don't need sub -10C uppers from the east to get snow. In 2010 we had snow from lower values. Cold from that direction has lower dew points compared to other directions. So there's more wiggle room. 

Edited by Frost HoIIow
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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon

Once again, the JMA is probably the pick of the 12s, here T192:

image.thumb.jpg.2398a62a57e1ea34d10e3387d283ff7a.jpgimage.thumb.jpg.2d62ec78fce178badc72187113c6eb43.jpg

This really does have the Aleutian low, Scandi high  combination, so should influence the strat, squeeze on up there:

image.thumb.jpg.edbd7678bcbcf1173796a944afff7494.jpg

There is a lot to like across the output tonight, both near term and slightly longer term...

Edited by Mike Poole
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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL
11 minutes ago, Met4Cast said:

One heck of a mean chart!

MEAN.thumb.png.f93b4200f51f64c12159904376fa222a.png

Extended EPS slowly trickling out now but fairly decent support for the Op within the ensembles out to day 9 at least. Whether the UK can tap into any properly cold air remains to be seen but the overall NH pattern is what's interesting to me at the moment

I was saying earlier the Scandy heights needed to be a little further North, well to me this mean chart shows exactly that , heights being centred a few hundred miles north of the Op. 
With this, I reckon further into the extended EPS there could be some pretty cold runs showing up. 
Edit - actually, looking at the map orientation my statement is incorrect!! Still, it looks nice!! 

Edited by Ali1977
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Posted
  • Location: Morecambe
  • Location: Morecambe

Much rather see more of a northerly influence showing across the outputs but that is looking unlikely. The details from each run will continue but the general trend is that the UK will stay on the cooler side of the jet but it never gets all that cold where snow at lower levels becomes a possibility. At least not yet anyways. 

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Posted
  • Location: Gillingham, Kent
  • Weather Preferences: Snow, Thunderstorms,
  • Location: Gillingham, Kent

Extended EPS relax the blocking around the UK although perhaps still indicative of a NW>SE tracking jet, that's notable is the complete lack of a signal for the TPV to setup anywhere near Greenland 

MEAN.thumb.png.63975f08f4c62afea3c738e1a185a667.png

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon

ECM ensemble mean 12z, T168 and T240:

image.thumb.jpg.ccd7152b680cdd4f16e2b66e99d7d6fe.jpgimage.thumb.jpg.7c1f77104086a0da90af99538e754253.jpg

Yep, take those, obviously at T240 it is a bit more of an average, but seems to show clear -AO.

Edited by Mike Poole
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
1 minute ago, Met4Cast said:

Extended EPS relax the blocking around the UK although perhaps still indicative of a NW>SE tracking jet, that's notable is the complete lack of a signal for the TPV to setup anywhere near Greenland 

MEAN.thumb.png.63975f08f4c62afea3c738e1a185a667.png

What's the 500mb chart like please?

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
9 minutes ago, Met4Cast said:

Blocky and slidey

ecmwf-ensemble-avg-nhemi-z500_anom-4164800.thumb.png.0e9258de1e47f500fe2bea7d0c7bb5af.png

Like that one!!  Very -AO, positioned with Aleutian low and Scandi high to have good impact on the strat....all very interesting.

Speaking of the strat, vortex intensity looking to peak in about 7 days time, before it comes under pressure:

image.thumb.jpg.adc351573f8ef1a794f76344ac57a34b.jpg

Edited by Mike Poole
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Posted
  • Location: Sedgley 175metres above sea level
  • Weather Preferences: Any kind of extremes. But the more snow the better.
  • Location: Sedgley 175metres above sea level

Pardon me for ramping..... But get in there you beauty!! The ECM mean is colder than last night.... I will take that, and say over to you Mr GFS

EDM0-144 (1).gif

EDM0-168 (1).gif

EDM0-216 (1).gif

EDM0-240 (1).gif

graphe_ens3 (2).png

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Posted
  • Location: Co.Laois > Ireland
  • Weather Preferences: Historical weather events. ❤ the seasons! Winters crisp snow!
  • Location: Co.Laois > Ireland
2 hours ago, Mike Poole said:

Liking where the GEM ends up here at T240:

image.thumb.jpg.2b696585afaf061e09f312890cf7be3c.jpgimage.thumb.jpg.8758077f71ec4f5258521b6a8cc81efc.jpg

Both from the perspective of the turmoils of the trop vortex, but also as these sorts of synoptics are now tending to draw colder air to the UK at mid November. 

Theres going to be a crunch point soon, where we start to get an idea of what the position will be going into December, with the main options being SSW, continued trop strat vortex disconnect, coupling of trop and strat vortex, where's your money?

Any chance all three main options could happen before Easter? I fancy a real cold start to December. Get it in first and would be good for christmas and migrating birds, environment etc. Thanks

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Posted
  • Location: Camborne
  • Location: Camborne

The evolution of the EPS ext mean anomaly is not dissimilar to the GEFS in some ways. Linking high pressure across the Pole and the vortex N. Canada developing another trough that extends south east to eventually link to the UK and Iberia. Thus still a very strong upper flow exiting the eastern seaboard which again diverges and abates west of the UK courtesy of the European ridge and the trough. So still a slack gradient over the UK and a tricky surface analysis with temps a tad below average

ecmwf-ensemble-avg-nhemi-z500_anom_5day-4164800.thumb.png.0160463e239a9171138e5c58baf56ed7.pngecmwf-ensemble-avg-nhemi-t850_anom_5day-4164800.thumb.png.0f99e76bb9ad57d34de55781796682f8.pngecmwf-ensemble-avg-eur-t2m_c_anom_5day-4164800.thumb.png.9c1f888eb26c2b2508531ab5f56d892a.png

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
13 minutes ago, icykev said:

Any chance all three main options could happen before Easter? I fancy a real cold start to December. Get it in first and would be good for christmas and migrating birds, environment etc. Thanks

Well, the continuation, status quo one really has to happen first or it is not the status quo! But re the other two, if the vortex intensifies and couples, maybe potential for SSW down the line leading to back loaded cold (possibly), but maybe also it is fair to point out, the possibility of the write-off total winter mildfest!  Likewise if the SSW happens early, front loaded cold possible, but the vortex should re-form and we might get a milder later half of winter.  Early winter cold is possible without a SSW if the status quo option persists, but it would likely be more time limited.

Hope that helps, I guess the key points are the timing of any SSW or strat trop vortex coupling.

Edited by Mike Poole
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Posted
  • Location: Buckinghamshire
  • Location: Buckinghamshire

Very interesting end to the Ecm this evening with high pressure around Scandinavia but remaining unsettled over the UK.

1533774798_EUROPE_PRMSL_HGT500_240(13).thumb.jpg.38e28d635dce098835a7407aee335fa2.jpg

Gfs keeps the weather dominated by areas of low pressure over the next week or more with them continuing to get stuck across the UK giving some places pretty significant rainfall although rainfall will be pretty varied so some places despite the pattern looking really unsettled likely seeing a fairly small amount over the next few days.

GFS.. 

1478722353_EUROPE_PRMSL_168(1).thumb.jpg.2db19d8656098b3307be65bf20eb2768.jpg

1040163594_EUROPE_PRMSL_192(1).thumb.jpg.57924bd17a9ce60a02c23e9544650572.jpg

Gfs ensembles now much more spread on upper air temperatures for the longer term with some really mild upper air temperatures on some but at this time of year inversion can do wonders especially if that's accompanied by high pressure slap bang over the UK.. Others are fairly cold but too much spread atm for any sort of trend this evening anyway.. :oldgood: Still alot of rainfall spikes for my area for a while yet. 

1395289607_ens_image(21).thumb.png.8607905485edf4fbc22a2abe1d007cd6.png

Edited by jordan smith
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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
4 hours ago, jules216 said:so a more La Nina December you think? PM shots and enhanced subtropical ridging but not enough for proper - NAO? If the enhanced subtropical ridge will be Sceuro one not Azores one Europe will be looking at mild December then. I am also going for back loaded winter,many analogs pointing out that direction.Its a risky one again thinking of last February failed blocking signal

Yes in terms of December. Various reasons for that, but primarily the atmospheric Nina tendency sitting alongside a very neutral ENSO signal and the general observed propensity for Decembers to be the peak of vortex influence and intensity. However SSTs lead me to think the southerly trajectory of the jet may continue, particularly when set alongside the persistent  -NAO context of much of 2019, so I think generally unsettled for the first 2/3 but temperatures around average and not warm. For me the most +NAO part of winter. However I’ve been wondering about the possibility of substantive November wave 2 forcing on the stratosphere for a little while, and the signal for this appears to be strengthening. If we get a sustained disconnect between the strengthening vortex, or even some form of split, then a more meridional month may result with the possibility of more stark temperature variation - not necessarily a cold anomaly. But I want to watch how great the strat warming signal becomes over the next 2 weeks before risking changing the overall sense of a predominantly unsettled December. 

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Posted
  • Location: Solihull, Midlands. (Formerly DRL)
  • Weather Preferences: Sunshine, thunder, hail & heavy snow
  • Location: Solihull, Midlands. (Formerly DRL)
2 hours ago, feb1991blizzard said:

Hurdle overcome - its fine. Better than the 0z at the end.

image.thumb.png.b123f244df06e4f63c2e2f0327d65950.png

Certainly a lot of great possibilities there. That Vortex looks toast!

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon

I want to try and illustrate what is forecast re the stratospheric and tropospheric vortex interplay, with these charts at T240 from the GFS 0z.  The first chart is from stratobserve.com and approximates the strat vortex as an ellipse coloured yellow (1hPa) -top to orange (150hPa) -bottom:

image.thumb.jpg.126b09ab07086a244b1dde28ea1273e6.jpg

First compare the yellow with the 10hPa temperature chart from Meteociel that is often posted here (comparing apples and oranges here as one is an ellipse based on height, the other is temperature but they both illustrate well the shape of the vortex)

image.thumb.jpg.352a669652472301ce275bc9b3328bbd.jpg

They look the same shape and orientation.  Now compare the orange with the tropospheric pattern (colours are 500hPa geopotential height):

image.thumb.jpg.ddf81f595598d25ec76d6ee1694739da.jpg

The orientation at 150hPa is (maybe) vaguely aligned, but the 500hPa pattern is just a mess, it would be hard to draw an ellipse that approximated it.  If the orange ellipse on this strat chart matches the trop pattern then we will be in trouble re winter cold, but as of now they don't.  At all.

Edited by Mike Poole
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