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Model output discussion - Winter has arrived and the hunt for cold is on

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35 minutes ago, Catacol said:

Not really sure what most of this means. Can’t ever remember seeing a static NH wave pattern, Russian High isn’t automatically a winter killer because it implies upstream troughing, and we certainly aren’t in a period of zero Pacific forcing. The Pacific is certainly hard to read at the moment, hence the jumble of options on the medium range table, but the forcing is present which is why we have a signal for returning heights. “de-facto a flattening pattern” ? Don’t see that either. Models can’t get a grip on the unusual convection profile, but some degree of progression now likely

image.thumb.gif.5618430e90fbfe5c338393845ba4534d.gif

The pattern won’t be flat in the last third of the month, but it is no easier today to work out where heights may emerge. RMM plots of the MJO are all over the place, and forecasts both for the UK and upstream in the US are changing on an almost daily basis. Wave 2 forcing is imminent 

image.thumb.gif.b00a230d8d786a30c047630c25b03264.gif

but thus far of modest magnitude. SSTs retain an interesting degree of support for northern heights under a southerly tracking jet

image.thumb.gif.3766712c01939f17863bb656048e99ea.gif

 

And the CPC sees anomalous ridging potential to the north with the Atlantic trough hitting the buffers to some degree

image.thumb.gif.b0ac061ade88960431b72a8c1b2efdc4.gif

Where does this leave surface conditions over the UK in the Xmas/New Year period? I’d still genuinely say it is wide open with multiple scenarios possible. A week of topsy turvy NWP output is the only certainty right now.

 

I was quite suprised to see SSTs generally below average around the UK C..

One has to hope for a change of fortunes soon, surely this rain will have to abate at some point.

Edited by northwestsnow
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12 minutes ago, Catacol said:

Not really sure what most of this means. Can’t ever remember seeing a static NH wave pattern, Russian High isn’t automatically a winter killer because it implies upstream troughing, and we certainly aren’t in a period of zero Pacific forcing. The Pacific is certainly hard to read at the moment, hence the jumble of options on the medium range table, but the forcing is present which is why we have a signal for returning heights. “de-facto a flattening pattern” ? Don’t see that either. Models can’t get a grip on the unusual convection profile, but some degree of progression now likely

 

Yes, awaiting the background signals to infect the algorithms as at the moment no sign of a Pacific wave. It is what the current models show and I understand and have reiterated, "all subject to change".

With regard to the Russian High, that has proved a thorn in "UK winter 2019"; of course, not every year is that the case, but certainly based on the last 2-months a poll of members would say "no thanks".

A flattening pattern refers to the lack of sustained height rises, even with wedges and mini-ridges, they seem to never fulfil the promise, all the more irritating as the tPV has remained pliant.

Of course, I hope, as we all do, to see something as you suggest, but until then, it is what it is, especially as last year, the output did not always comply with what those background signals signposted.

Edited by IDO
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1 hour ago, BLAST FROM THE PAST said:

It might be Feb, a cold Xmas week and NYE would be nice....pM air often doesn’t bring the goods...and unfortunately it hasn’t this time thus far and this could be the best we get 😲...some mention GP but I’m sure he’s angling for at least a very mild Jan?  Not gospel but I’m sure I read that he is.

 

BFTP

Yes he is but whilst he hasn't actually predicted a cold Feb, he has left it open - in other words it is still possible, at least some spells and without wishing to put words in his mouth, i am guessing he certainly wouldn't be writing off a potent Easterly very late in Feb as some of his forecasting methods are analogue based and not on long range modelling and they point to at least a chance the later you go.

 

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55 minutes ago, Catacol said:

Not really sure what most of this means. Can’t ever remember seeing a static NH wave pattern, Russian High isn’t automatically a winter killer because it implies upstream troughing, and we certainly aren’t in a period of zero Pacific forcing. The Pacific is certainly hard to read at the moment, hence the jumble of options on the medium range table, but the forcing is present which is why we have a signal for returning heights. “de-facto a flattening pattern” ? Don’t see that either. Models can’t get a grip on the unusual convection profile, but some degree of progression now likely

image.thumb.gif.5618430e90fbfe5c338393845ba4534d.gif

The pattern won’t be flat in the last third of the month, but it is no easier today to work out where heights may emerge. RMM plots of the MJO are all over the place, and forecasts both for the UK and upstream in the US are changing on an almost daily basis. Wave 2 forcing is imminent 

image.thumb.gif.b00a230d8d786a30c047630c25b03264.gif

but thus far of modest magnitude. SSTs retain an interesting degree of support for northern heights under a southerly tracking jet

image.thumb.gif.3766712c01939f17863bb656048e99ea.gif

 

And the CPC sees anomalous ridging potential to the north with the Atlantic trough hitting the buffers to some degree

image.thumb.gif.b0ac061ade88960431b72a8c1b2efdc4.gif

Where does this leave surface conditions over the UK in the Xmas/New Year period? I’d still genuinely say it is wide open with multiple scenarios possible. A week of topsy turvy NWP output is the only certainty right now.

 

I am not sure if I agree that Russian/East European high isnt a winter killer as it already killed about 7 weeks of wintry potential + another at least 2 weeks forecast on the back of record breaking mild spell in Continental Europe commencing tomorrow, for how long are we going to say its good for long term prospects while no winter is going to unfold. @IDO has quite accurantelly summed up the state of play and has been posting well measured thoughts throughout. Its no one's fault that its turning out to be disapointing winter so far, actually UK/IE and North Scandi are not doing as bad as other continental regions. 

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1 hour ago, russell k said:

The French Meteo model shows [email protected] 1100m suggest this is for a higher altitude

Yes it’s for 1500m. Not much skiing happens below 1100m. Perhaps bottom runs into resorts will be a bit slushy but that’s not unusual for Christmas in lower resorts 

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1 hour ago, Catacol said:

Not really sure what most of this means. Can’t ever remember seeing a static NH wave pattern,

 

As recent as Jan 2019 we saw a static wave over the UK: anim_bva7.gif

Also, the historical Triple R ("Ridiculously Resilient Ridge") in the Pacific in the early noughties, was a mega-static-block!

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Not much comment on the ukmo so far today.i was under the impression it was ready for lift of in certain quarters ?still think EC at ten days is at the extreme on the nhp outlook in regard to cool -cold.that said what do I know en!!😒

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2 hours ago, BLAST FROM THE PAST said:

Just wait until Jan and Feb.....we’ll see if the much vaunted hoped for 2nd half pattern change happens 😃  It’s now reminding me of winter 08/09

 

BFTP

Hope you are correct.The NH pattern at the end of Dec can many times govern what the following two months of winter will be like.Read that in a weather book some time ago.So looking for sign of pressure building over the Arctic and Siiberia by months end,or we could be chasing shadows for weeks.

 

 

 

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An area of low pressure spiralling round to the Northwest of Scotland will move into Western parts of Scotland during tomorrow morning, with cold air in situ then this rain/sleet for Western coasts is likely to fall as snow in central and perhaps northern parts of Scotland especially on higher ground but some to lower levels is likely this could be quite heavy in places too with some accumulations in places although remaining towards a wintry mix/rain around Western coasts. How widespread this will be is currently uncertain but it looks likely that some fairly heavy snowfall will fall in parts of central and perhaps northern Scotland for a time tomorrow morning into the afternoon before probably easing by evening although patchy light sleet snow will likely linger into early hours of Tuesday before clearing away. 🌨️

Icon.. 👇

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Arpege.. 👇

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Edited by jordan smith
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25 minutes ago, SLEETY said:

Hope you are correct.The NH pattern at the end of Dec can many times govern what the following two months of winter will be like.Read that in a weather book some time ago.So looking for sign of pressure building over the Arctic and Siiberia by months end,or we could be chasing shadows for weeks.

 

 

 

No, what I mean is it’s not anticipated by me....I’m expecting a very mild Jan, and Feb with fleeting cold.....HP in wrong place scenario

 

BFTP

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9 minutes ago, BLAST FROM THE PAST said:

No, what I mean is it’s not anticipated by me....I’m expecting a very mild Jan, and Feb with fleeting cold.....HP in wrong place scenario

 

BFTP

Ouch I guess your winter forecast has changed then.I doubt the pattern  will remain the same for the next two months,the models are still struggling 7 days out.

Keep the faith.I know some of the experts are predicting a bitter outbreak early january 

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9 minutes ago, SLEETY said:

Ouch I guess your winter forecast has changed then.I doubt the pattern  will remain the same for the next two months,the models are still struggling 7 days out.

Keep the faith.I know some of the experts are predicting a bitter outbreak early january 

Yep that’s one winter forecast no longer supported by its author after just 15 days. Agree we need to keep faith that we’ll get some cold shots over the season. But any prolonged cold looks unlikely this month and January has been written off by GP. We will see if he’s right or wrong but regardless the hunt goes on. 

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It's clear from the London ens there is a large spread on the lead up to Christmas.

ensemble-tt6-london.thumb.gif.a149286c9eb0a628bf2c9cff2ef17258.gif

They suggest that any warm up looks likely to ebb away as temperatures are trending down again.This is quite possible with the mean jet path just to our south.

The ECM day 10 for a cold northerly is an outsider but all it needs is a small Atlantic ridge at the right time.As we are mainly north of the jet we are closer to the cold air just to our north so it's an evolution that can't be discounted.

mean day 10

EDM0-240.thumb.gif.8faa5992d2e8f2aef04fd0d10d472216.gif

With the current fairly flat hemispheric pattern we can't really expect a major block to appear out of nowhere by Christmas but i guess many would happy just to see a short Christmas cold snap. 

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24 minutes ago, SLEETY said:

Ouch I guess your winter forecast has changed then.I doubt the pattern  will remain the same for the next two months,the models are still struggling 7 days out.

Keep the faith.I know some of the experts are predicting a bitter outbreak early january 

Good thing I’d say might finally get something right... 😄 

EPS keeping with emergence of northern lat blocking soon after day 10 and it seems to be getting closer will it be robust enough? A much drier end to December seems to be in pipeline weaker jet, hopefully colder too I don’t think that can be ruled out before 2020. Vortex may be very strong but seems there’s a disconnect the TPV stuck mainly over Arctic Archipelago with -NAO & E Siberia not a bad place for it to reside I suppose it’s not all doom and gloom! 

DEA6A743-5A86-4CFC-8CE6-7E92C3715026.thumb.png.bbc471185dc98d0e8fc6acd2edde4366.png

Edited by Daniel*
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3 hours ago, BLAST FROM THE PAST said:

It might be Feb, a cold Xmas week and NYE would be nice....pM air often doesn’t bring the goods...and unfortunately it hasn’t this time thus far and this could be the best we get 😲...some mention GP but I’m sure he’s angling for at least a very mild Jan?  Not gospel but I’m sure I read that he is.

 

BFTP

As far as I understand it I think GP was indicating a cyclonic Jan? If the jet stream stays south then that could mean plenty of PM air and therefore not that mild.

Of course it may be that he just meant a train of SW'ly's propped up with a Euro high 🤮

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1 hour ago, SLEETY said:

Ouch I guess your winter forecast has changed then.I doubt the pattern  will remain the same for the next two months,the models are still struggling 7 days out.

Keep the faith.I know some of the experts are predicting a bitter outbreak early january 

No not changed, Jan and Feb more likely mild.....chance of better HP positioning still there....but not high

 

BFTP

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Ukmo and GFS 12z so far,wet!! Really need a drying out period asap.guess it's generally normal Dec weather but hopefully the new year brings a change

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Much colder air trying to come down from the NE ,but nearly always low pressure is too far north so it can’t undercut because high pressure is building up from the South at the same time,so frustrating.

 

yet any other season,no high pressure to the South of u.k. for weeks and weeks.The weather gods hate cold weather fans in the u.k. 😒

Edited by SLEETY
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Una pena. No nos quitanos la zonal ni a tiros.

What a pity. Bad news with GFS.

Edited by Corisa

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GFS12 well this could go into cold christmas days image.thumb.png.2f965599c94fc0746980e81e4e813430.pngimage.thumb.png.0c70bece177ea70ef2ae866869a561e6.png

 

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6 minutes ago, SLEETY said:

Much colder air trying to come down from the NE ,but nearly always low pressure is too far north so it can’t undercut because high pressure is building up from the South at the same time,so frustrating.

 

yet any other season,no high pressure to the South of u.k. for weeks and weeks.The weather gods hate cold weather fans in the u.k. 😒

Yes at the moment it looks this way and yes incredibly frustrating with a vortex so disrupted. Right now if we won the lottery we’d lose the ticket. But we keep chasing and hopefully those who suggest something more seasonal for Christmas are right. It’s still possible!! As they say in the polar express, Believe!

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4 minutes ago, Dennis said:

GFS12 well this could go into cold christmas days image.thumb.png.2f965599c94fc0746980e81e4e813430.pngimage.thumb.png.0c70bece177ea70ef2ae866869a561e6.png

 

All in fi Dennis but Xmas day looks a washout there.still who knows after

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I really don't see why many people are so disappointed with the recent output as of late even with the higher "uncertainty" the likely as to happen is a return to sightly milder temps just before Christmas day with a "topper" cold air from the north for a few days before returning to milder and wet

It may still turn colder but looking very unlikely as the ECM was a huge outlier and will most likely fall into place with the other models as many others has said a lot of things are at us even with the "background signals" the seasonal forecasts are "mostly accurate" for a reason...

 

 

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