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Paul

Model output discussion - 7th January onwards

Paul

Please keep this thread solely to discussing the model output. The model banter thread is available for more loosely model related chat, ramps and moans.

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GEFS 6z is a bit of a downgrade compared to the 0z for upper air temps. Less members sustaining in the -10 to -15 range. 12z will probably upgrade again no doubt!

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2 hours ago, TEITS said:

Some classic old school charts appearing. Makes me want to listen to some Human League records!

GFSOPEU06_210_1.png

Yep! Don’t You Want Me Baby was number 1 in December 1981!

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https://longrangesnowcenter.blogspot.com/2019/01/europe-on-long-term-jan-19th.html
An extract from my latest long range outlook below. 
"My overall view is that from the last week of Jan to the second week of Feb, will feature major snow risks for the Southern Alps and the UK. There will be plenty of cold around, but not so much snow for the Northern Alps. We should see a neutralisation in the later stages of the month."

The outlook includes my thoughts on the GWO (click image below), and my thoughts on the latest EPS 46 run.

IMG_6241.thumb.PNG.96eb6f7c8493f5e0e51bf5c2607b9d07.PNG

 

 

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Just now, Djdazzle said:

Yep! Don’t You Want Me Baby was number 1 in December 1981!

They don't sound like a pop group do they, sound like more of a left wing pressure group.

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I still think if it happens next week it is a bonus, the fun and games will be in February..

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11 minutes ago, londonblizzard said:

GEFS 6z is a bit of a downgrade compared to the 0z for upper air temps. Less members sustaining in the -10 to -15 range. 12z will probably upgrade again no doubt!

I think we're in a rare situation where downgrades aren't really downgrades. I know technically you're right but it sounds worst than it is. With the incredible charts we're seeing atm, there's very little room for upgrades but plenty in the opposite direction. 

I love when there's room for error because even a watered down version would deliver the goods.

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13 minutes ago, londonblizzard said:

GEFS 6z is a bit of a downgrade compared to the 0z for upper air temps. Less members sustaining in the -10 to -15 range. 12z will probably upgrade again no doubt!

I haven’t had a chance to look at them all but upper air temps aren’t the best guide to snow chances if you have a set up of Atlantic trough disruption meeting embedded cold at the surface.

Snow can easily fall at just below freezing at the 850 level if you have low dew points from mainland Europe being pulled nw to meet any precip .

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7 minutes ago, bluearmy said:

just a reality check .... it might be worth thinking about some of the decent cold spells of the past decade and then viewing the archived runs that were being thrown out for the week two period back then. It’s very unusual to see the verification live up to the levels of deep cold etc that were being shown 9/13 days ahead .....what is important to see is the potential longevity of the pattern .... the more bites at a potential snow event we get, the more chances we have of one sticking ..... especially once we have surface cold in ...

onto the 12z’s ....... don’t expect to see anything in particular ......just enjoy the ride for the time being ....

Interestingly December 2010 actually kept upgrading and extending the cold spell, so lets hope this keeps up that idea. The Feb 18 cold shot also got increasingly severe closer to the time (though did ease just a touch as we drew down to 48hrs out, but it was way lower than what the charts a week ago suggested).

However I know what you mean, typically it does weaken the cold flow as we draw closer, especially once we are out into FI.

Nick, your right, with fairly low thicknesses on most of those ensembles plus contientnal flow of some type should mean we shouldn't need 850hpa below -3c.

Edited by kold weather

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February looking cold as well - not just an isolated run either - this is about the time you want them on board as well.

image.thumb.png.11070f56c769dba2ae2412a7dec130d7.png

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Beware, remember the great model backtrack from a couple of winters ago when at day 5/6C there were -10C - -15C uppers banging on the door for a sudden seismic and almost instant flip in the models and we ended up with mild westerlies? Not saying that will happen but with so many inter/intra model variances there's still a lot of up and downs to through yet. 

Being in pretty much the least snowiest place in the country I'm trying not to look at the precip charts, down here we are sheltered by a long land track from any direction north or west/east if that makes sense and have a warm body of water directly south such inevitably quick raises wet bulb temps with a flow from the sea. Hopefully as we get closes to the middle and end of next week some of little polar lows will start churning westwards which I would have thought is good possibility or better still a proper channel low.

I'm not a big cold or snow fan but if got to happen this is the best time as most optimal for cold and snow so it can go hard or go home as far as im concerned!! 

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8 minutes ago, warrenb said:

I still think if it happens next week it is a bonus, the fun and games will be in February..

Don't think so. For what seems like ages we have been looking at around 21st January for the change to cold. Anything before that is a bonus, but after is now coming into the realms of the expected. 

All signals are now green, with the exception of a single amber light for NE US storm over the weekend, and even if that amber light is correct, it is a slowdown in the charge towards cold rather than a turnaround. 

The background signals have been signposting this for some time, and now we are on the cusp. I'm looking forward to @nick sussex musings on irritating shortwaves that may be the difference between heavy snow and slightly less snow rather than the more normal knife-edge situations we usually find ourselves in.

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13 minutes ago, bluearmy said:

just a reality check .... it might be worth thinking about some of the decent cold spells of the past decade and then viewing the archived runs that were being thrown out for the week two period back then. It’s very unusual to see the verification live up to the levels of deep cold etc that were being shown 9/13 days ahead .....what is important to see is the potential longevity of the pattern .... the more bites at a potential snow event we get, the more chances we have of one sticking ..... especially once we have surface cold in ...

onto the 12z’s ....... don’t expect to see anything in particular ......just enjoy the ride for the time being ....

That's interesting, because the extent to which the cold air is moving to the south of Europe also looks pretty outrageous at this stage. Is this likely to modify too?

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12 minutes ago, Alderc said:

Beware, remember the great model backtrack from a couple of winters ago when at day 5/6C there were -10C - -15C uppers banging on the door for a sudden seismic and almost instant flip in the models and we ended up with mild westerlies? Not saying that will happen but with so many inter/intra model variances there's still a lot of up and downs to through yet. 

Being in pretty much the least snowiest place in the country I'm trying not to look at the precip charts, down here we are sheltered by a long land track from any direction north or west/east if that makes sense and have a warm body of water directly south such inevitably quick raises wet bulb temps with a flow from the sea. Hopefully as we get closes to the middle and end of next week some of little polar lows will start churning westwards which I would have thought is good possibility or better still a proper channel low.

I'm not a big cold or snow fan but if got to happen this is the best time as most optimal for cold and snow so it can go hard or go home as far as im concerned!! 

I'd say with the SSW impact there'd surely be less of a chance (of a backtrack) but you never know

Edited by CanadianCoops

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26 minutes ago, bluearmy said:

just a reality check .... it might be worth thinking about some of the decent cold spells of the past decade and then viewing the archived runs that were being thrown out for the week two period back then. It’s very unusual to see the verification live up to the levels of deep cold etc that were being shown 9/13 days ahead .....what is important to see is the potential longevity of the pattern .... the more bites at a potential snow event we get, the more chances we have of one sticking ..... especially once we have surface cold in ...

onto the 12z’s ....... don’t expect to see anything in particular ......just enjoy the ride for the time being ....

Funnily enough I was looking at 10/11/12 Feb 1994 recently. A great easterly but not a lot of snow of I remember rightly. However we seem to have the potential for undercuts and approaching fronts this time, which we didn’t in ‘94. 

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A multi model flip seems unlikely this time in terms of a definite cold spell. Such a strong signal for this to be the case over at least the next fortnight.

Biggest concern is where the precip will fall and how much. Too early to say of course, but the longer we stay cold/very cold, the greater the potential opportunities arise.

I'd prefer a week of cold and plenty of snow, rather than a fortnight of showers/light stuff. Give me those 50p size flakes!!!

Anyone know whether AROME/ARPEGE/HIRLAM is most trustworthy for precip types/amounts?

Edited by Runcible Spoon

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10 minutes ago, helentheroberts said:

That's interesting, because the extent to which the cold air is moving to the south of Europe also looks pretty outrageous at this stage. Is this likely to modify too?

Invariably - yes

the models tend to show stuff further out that’s simply so unprecedented that it just won’t verify - obviously there are occasions which contradict this like last feb/March where the deep cold pool survived its arrival at the Baltic Sea and made the long track across - but the strength of the reversal wave was exceptional as was seen by how far into the Atlantic it got ....

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1 minute ago, Runcible Spoon said:

A multi model flip seems unlikely this time in terms of a definite cold spell. Such a strong signal for this to be the case over at least the next fortnight.

Biggest concern is where the precip will fall and how much. Too early to say of course, but the longer we stay cold/very cold, the greater the potential opportunities arise.

I'd prefer a week of cold and plenty of snow, rather than a fortnight of showers/light stuff. Give me those 50p size flakes!!!

Anyone no whether ARMOE/ARPEGE/HIRLAM is most trustworthy for precip types/amounts?

50p flakes means things are marginal, what you really want is tiny, dry powder snowfall, when that type of snow falls you know you’re in a cold spell!

All the models have their flaws.. I tend to use EURO4/APERGE blend but it depends how they fit in with the other Hi-Res models. 

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At 144h the GFS and ECM solutions are rather different, and I know what I'd put my money on at that range. And although it has been done to death I'm convinced there is at least a grain of truth in the US shutdown affecting the accuracy of the GFS output. Very sad to see the full implementation of the FV3 has been delayed.

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13 minutes ago, Paul_1978 said:

Funnily enough I was looking at 10/11/12 Feb 1994 recently. A great easterly but not a lot of snow of I remember rightly. However we seem to have the potential for undercuts and approaching fronts this time, which we didn’t in ‘94. 

You must have got belted on that overnight Monday into Tuesday from that front coming up from the South West.

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5 minutes ago, Seasonality said:

At 144h the GFS and ECM solutions are rather different, and I know what I'd put my money on at that range. And although it has been done to death I'm convinced there is at least a grain of truth in the US shutdown affecting the accuracy of the GFS output. Very sad to see the full implementation of the FV3 has been delayed.

Both are great solutions . We’ve seen variations of where any high is between outputs which is normal at this stage .

If the Euro troughing holds to the se then cold remains locked in for the UK.  There is no other set up which is so overwhelmingly correlated with UK cold .

 

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15 minutes ago, Paul_1978 said:

Funnily enough I was looking at 10/11/12 Feb 1994 recently. A great easterly but not a lot of snow of I remember rightly. However we seem to have the potential for undercuts and approaching fronts this time, which we didn’t in ‘94. 

Later Feb '94 was though! the days ruled, 22-24th, sure I had 72 hours continuous snow! the days when Atlantic air failed to win against the cold air! and result snaw

archives-1994-2-24-0-0.png

Edited by I remember Atlantic 252

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Just now, nick sussex said:

Both are great solutions . We’ve seen variations of where any high is between outputs which is normal at this stage .

If the Euro troughing holds to the se then cold remains locked in for the UK.  There is no other set up which is so overwhelmingly correlated with UK cold .

 

Oh definitely Nick! Its all positive for UK cold that much is true.

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