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Model output discussion - mid-winter

Paul

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Gefs offer 25% support for high heights over Scandi by day 10. Suspect the eps clusters will be around 20%. 

Thats enough for a starting point and not dismissable, especially given the extended trend. 

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3 minutes ago, bluearmy said:

Gefs offer 25% support for high heights over Scandi by day 10. Suspect the eps clusters will be around 20%. 

Thats enough for a starting point and not dismissable, especially given the extended trend. 

I guess that the fact that opp and control went together is a big plus. Probably worthy of a raised eyebrow at this point but not much more.

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Interesting ECM! Just goes to show what could happen and quite quickly.

Now don't shoot me down for posting this, I know these charts aren't the same and I'm not saying we are heading for a historical cold spell or anything like that. But I just wanted to point out the evolution from 1947 to today's ECM, I love the way today's ECM sucks that high North in the fashion it does and voila a 'proper cold spell' is on the horizon, also note toward the end of the ECM the cold building rather than moving away. Let's hope it's a trend and a very good one at that. 1947 popped up so to speak out of knowhere.

archivesnh-1947-1-18-0-0.thumb.png.cca0dd5c2bc743844660e9c8d621e2c7.pngECH1-144.GIF.thumb.png.3bc710ea54456997dc1ed819f4add53f.png

archivesnh-1947-1-19-0-0.thumb.png.b6f26e71aaa248f883d92354b666295b.pngECH1-168.GIF.thumb.png.8b8d644fb834beb4af8494e5859b2fec.png

archivesnh-1947-1-20-0-0.thumb.png.01868d0c68d01cebb0c31744fa46b3a0.pngECH1-192.GIF.thumb.png.e81bcb5f0bae583cb69d3424a2a84013.png

archivesnh-1947-1-21-0-0.thumb.png.906ae919eeb49cf967371021e47c6701.pngECH1-216.GIF.thumb.png.d12eca75f490997546f3096d7442dce4.png

archivesnh-1947-1-22-0-0.thumb.png.ac07ffbbf1b105364471855c7df1a1ad.pngECH1-240.GIF.thumb.png.4c36f2da7eb20ef1e6fed904bcbcc8bf.png

The cold building out east toward the end of the ECM

ECH0-192.GIF.thumb.png.4d73c97b6504b103a1fac94cfaf0976a.pngECH0-216.GIF.thumb.png.c31763d84b946a203581a1971ac4b5f3.pngECH0-240.GIF.thumb.png.675644cb590ee73cc339bcdc933b0102.png

This Winter does have the feel to me that we will get a proper cold spell sooner rather than later.

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Nice to see such good model agreement at T144hrs hrs! :D

The differences start as early as T72 hrs with the evolution of that upstream low. 

The ECM and UKMO are quite similar at that point , that’s where it ends!

The ECM has that more amplified Canadian high which helps to angle the trough ahead of it more sw at T144hrs .

 

Edited by nick sussex
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59 minutes ago, Penrith Snow said:

3rd time lucky?

How about 30th time lucky! Lol

Meanwhile its another green morning despite the weather warnings.

Wednesdays low shiftedslightly south again and if correct the centre would pass over my house, lots of snow for Southern Scotland and gales for Liverpool and Manchester.

Andy

I can assure you it's not green in most of Scotland ... pure white more like :-)

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Test question:

Which chart is better?

Which chart is a belter?

image.thumb.png.2dcc9a3b5d98deb52d2d383356118a4a.pngimage.thumb.png.5d056ac9a84fec1d67700576110debc1.pngimage.thumb.png.d962ed259127b9fe1e89ea24868ba05b.png

Which qustion refers to an adjective and which to an abstract noun?

And whilst we try to work out distracting trivia will an easterly creep up on us! :yahoo::D:D

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Strange to still see a 50/50 split in the ECM ensembles between runs developing the big storm for Wednesday night (north) and those with a more ordinary gale (south). You'd have to back the higher res of the op runs considering the event is so close.

Onto the "easterly", the ECM has support from the control but virtually no other member. Out to D12-15, perhaps 30% have reasonable blocks to the east (not necessarily aligned for maximum cold) and very few blocks to the north - most runs are still westerly - so although the trend for Scandi heights is still there, not quite as pronounced as yesterday.

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19 hours ago, Nick F said:

Although the operational runs have been churning out some rather unsavoury medium range charts for coldies yesterday and this morning, there does does appear to be quite a large spread developing in the ensembles from around the Sun 21st after winds briefly veer northwesterly or even northerly the day before. Could be that quite a few members are building a bit more of a ridge / weak block ahead of the next lobe of the trop PV that tries to push east out of NE Canada and turn the flow zonal / westerly. So perhaps we may see more of a delay than models currently show to the return Atlantic zonal onslaught early next week, with more of ridge perhaps forcing the jet a little further south as a result.

221D7BFC-9F19-45DA-AD80-5DAAF268D1BA.thumb.gif.f2c9f49eef70cc53780e4becef8fb491.gif

 

 

There were signs in the ensembles yesterday, particularly apparent in the EPS spread from 21st, that the return of Atlantic zonality was becoming less certain beyond the coming weekend. It seems like models are/were defaulting to a La Nina / warm phase of MJO pattern and trying to flatten out and bring in Atlantic zonality. However, re-emergence of blocking to the NE seems be increasingly picked up by the models now, putting the buffers on the Atlantic conveyor somewhat.

However, we need to cautious in not taking the 00z EC op too seriously until there is support from subsequent runs from both GFS and EC for a Scandi high to build and control our weather, as we have been lead down the garden path by the EC ops earlier this month with those Ely / NEly flows it showed. As @bluearmy indicates, not the support from the ensembles for now to have any confidence in the EC op ... for now.

Nearer in time and only 41 hrs away and still differences in depth for the low crossing early Thurs, though GFS, UKMO and EC broadly agreeing on the low crossing northern England, UKMET fax looks deepest at 978mb.

 

Edited by Nick F
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3 hours ago, Snowmadsam said:

Showing the tension AJ! 

Could be what ecm ens have been saying for while...are we going to be lead up a garden path again?

ah, cheers Sam.....I wasn't sure what you meant, and at that time of the morning, the best I can muster is 3 question marks....lol

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19 minutes ago, memories of 63 said:

Is the low a little further south on this run?

Barely. Very slight.

10619EC6-77E3-47BE-B8C8-25D8E004CFDB.thumb.png.674f2af1339eaf0687199ee4e942f624.png   EE2DCAC9-7936-4B60-9C73-F08A1C3558A0.thumb.png.16240f5247ed0b8228279175c6fb7ea9.png

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This low is causing all sorts of issues,  Perhaps not with Snow  but the potential for some high speed gusts  The Aperge and Icon  Still take 70+Mph winds through Wales Central Northern England  Through to East Anglia   one to keep an eye on. 

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Well the ECM op was put in a cluster of 12 but honestly it was the most extreme member of this cluster

ec-ens_nat_z500scenarios_2018011600_240.

But reasonable signals that ridging at mid and high latitudes will cause some interference at the end of the month

ec-ens_nat_z500scenarios_2018011600_276.

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Some absolutely belting downpours of hail on the coast of South Wales last night very frequent too which brought some temporary accumulations, these showers forming lines at times are expected to continue today & tonight but with the air & ground temperature becoming a bit colder compared to last night although no snow is forecast for us, hail accumulations could well increase as it lasts longer on the ground leading to very tricky driving conditions by this evening but fun for the kids as when this happened in December they were out playing in it and sliding down the street on their sledge. #hailisthenewsnow 

image.png

Edited by Draig Goch
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9 minutes ago, Man With Beard said:

Well the ECM op was put in a cluster of 12 but honestly it was the most extreme member of this cluster

ec-ens_nat_z500scenarios_2018011600_240.

But reasonable signals that ridging at mid and high latitudes will cause some interference at the end of the month

ec-ens_nat_z500scenarios_2018011600_276.

I take it this is " Man with Good news" ?

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Just now, Fozfoster said:

I take it this is " Man with Good news" ?

errrr, Man with good news and bad news :)  - good in that a pattern for cold might develop D11-D15, bad in that the ECM op D7-D10 is a genuine outlier

 

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14 minutes ago, Man With Beard said:

errrr, Man with good news and bad news :)  - good in that a pattern for cold might develop D11-D15, bad in that the ECM op D7-D10 is a genuine outlier

 

I think it would be safe to say that after the 20th there are a few options on the table... This for the Netherlands.

I would love to know what is causing this uncertainty on such a regular basis in the models, it seems like a weekly drama at the moment - will it / wont it :-)

image.thumb.png.17ace32c35ad8842083eea8ee67508ce.png

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Big swing in (synoptic) GEFS coming up in the extended..

Edited by Glacier Point
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39 minutes ago, Man With Beard said:

errrr, Man with good news and bad news :)  - good in that a pattern for cold might develop D11-D15, bad in that the ECM op D7-D10 is a genuine outlier

 

Could it be a genuine trend setter ? :D

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5 minutes ago, Glacier Point said:

Big swing in (synoptic) GEFS coming up in the extended..

Good way or bad way gp

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