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Model output discussion - 21st Jan Onwards

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Tentative signs of that mid Atlantic ridge, with jet stream seemingly wanting to take a more meridional flow 12z was as flat as a pancake, interesting let us hope this trend builds.

image.thumb.png.c9e43e88b642b98bcbed42f3

 

Edited by Earnest Easterly*
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2 minutes ago, Catacol said:

Medium term models provide a very broad brush. So within a signal for a mid atlantic ridge there are all kinds of mesoscale possibilities. Straight northerlies, damp NWesterlies, drier but very cold NEasterlies and even undercut scenarios bringing E or SEasterlies are all possible from a mid atlantic ridge even if the dominant vector over the period is mainly from N or NW. The news today is therefore good.... but second half of February needs the skies to stay cloudy....

Some of my deepest snowfalls have occurred in February....one overnight Feb 2010 period dumped a load of snow here. However, you're right, it won't stick on low ground for very long at all...perhaps even more pronounced this year due to anomalous warmth during December. That Feb 2010 snowfall was gone by dinner time.

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Pm blasts with -5/6 air over the country next Thursday and again at the weekend - crumbs of comfort from the GFS 18Z as the flow is more meridional than previous runs. Quite incredible the state of the Atlantic though for this stage in the winter - didn't see this coming at all!

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even towards the end of the run the jet stream is stronger than ever, only a temporary ridge and then more wet mild weather. If only a trough would head up west of Greenland we would be back in business, another trough leaving US (produced a lot of snow from it in US) heading our way.. I am a little  interested to see if  this trough veers north at the end of the run but i doubt it

 

Heights unfortunately where we dont want them in Bartlett terrtory

 

Edited by Derbyshire Snow

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Trop vortex done for....

It'll have another go at a Greeny high/mid Atlantic ridge from here...

npsh500.png

Edit: GFS FI wants to faff around with vortex spin-offs which preclude further ridging attempts

h500slp.png

Only delaying the inevitable though!

Edited by CreweCold

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The thing to keep an eye out is the overall NH pattern rather than the fine detail.

So does the PV split and does that ridge build into Alaska helping to amplify the upstream pattern in the east Pacific/west USA.

So two ticks for the GFS 18hrs run, its overall pattern was similar to the ECM at T240hrs.

I think we're going to have to suffer around 10 days of underwhelming weather, but at least some signs of changes upstream are showing.

Edited by nick sussex
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Mike Ventrice tweeted this morning that the El Nino has become more central based, which is a good thing for encouraging the eastern Pacific and U.S. pattern to back west, taking any residual Canadian vortex segment with it - far enough to allow more in the way of high pressure NW of the UK but unlikely to be so far as to encourage a west-based NAO.

So many pieces of the puzzle seem to be falling in favour of a notably cold spell being the dominant feature of Feb 2016 that I'm having trouble accepting it without my brain shouting nonsense such as  'Sod's Law' at me.

 

Anyway, I believe key thing to look out for in terms of model trends for the final week of Jan is reductions in the strength of the Azores/Euro high which are possible given the likelihood some overestimation of the short-term AAM drop by the models.

The bigger changes such as troughs diving into Europe and marked height rises to the NW become more plausible for the output covering the first week of Feb. That's the optimistic end of the timing while the pessimistic end is third week of Feb... a bit of wiggle room as usual and I for one am hoping we get there sooner rather than later else I'll be needing some exceptionally cold air to retain the majority of snow cover through daylight hours. I'll do my best not to let this influence my judgement on here, of course! :snowman-emoji:

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Conclusion tonight .I think to save this winter we really do need a SSW event to take place soon  to dramatically alter the upcoming zonal weather. Things can change but the state of our area of the Northern Hemisphere is not desirable, but one SSW could change  all that relatively quickly

Edited by Derbyshire Snow
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3 minutes ago, Derbyshire Snow said:

Conclusion tonight .I think to save this winter we really do need a SSW event to take place soon  to dramatically alter the present zonal weather. Things can change but the state of our area of the Northern Hemisphere is not desirable, but one SSW could change  all that relatively quickly

To be honest your getting to sucked into the models.  

We are not in "present zonal weather" we have had the first day where temps have got to 'normal' values .  So any predicted zonal weather at present is just that , predicted . It hasn't actually happened . 

I'm not sure how long we will be in this for . The models say 10 days or so , but I think maybe 7 days . I think another day or so and things will suddenly move forward ,  the last 2 days of the month to flip to Neg NAO/AO

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6 hours ago, Nick F said:

Looking at the extended EPS mean and control (to day 15) last few runs, the anomaly signal from them has been for the trop PV to shift east from Greenland into Scandi toward day 15, 06z GEFS mean + a fair number of members been hinting at this

Be interesting to see if the 12z GFS and ECM continue this theme ... and whether the NOAA CPC 8-14 day anomalies also pick up on this signal too...

NOAA CPC 8 - 14 day H500 anomalies now shows the 'sausage' of low heights just to our north extending east into Scandi and the strong Wly flow across the UK. 

image.thumb.gif.58a2952364e4f7148236d16e

but note also the cross polar ridging over the pole between west Canadian and Kara highs, which is clearer on the 12z GFS v EC height comparison:

image.thumb.gif.520b87efa70c68c32fcb125c

So after a brief return to more a +ve AO, falling back to -ve again as we enter early Feb? NAO staying +ve though for a while as those southern Euro +heights continue to be forced.

I think these signs from the models of the trop vortices gradually  displaced from the Arctic can only be a good sign for Feb prospects, so we are perhaps seeing one last gasp of the Greenland PV and Atlantic storminess for a few weeks before blocking returns.

 

Edited by Nick F
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6 minutes ago, Severe Siberian icy blast said:

To be honest your getting to sucked into the models.  

We are not in "present zonal weather" we have had the first day where temps have got to 'normal' values .  So any predicted zonal weather at present is just that , predicted . It hasn't actually happened . 

I'm not sure how long we will be in this for . The models say 10 days or so , but I think maybe 7 days . I think another day or so and things will suddenly move forward ,  the last 2 days of the month to flip to Neg NAO/AO

This is the good thing about a model discussion forum, we all have our own opinions. We are in one of the most difficult areas of the world to forecast more than 10 days ahead. I could be proved wrong but to me we are now entering  true winter zonal weather with a relentless throw of depressions across the Atlantic. Heights in poor position everywhere. I would love to be proved wrong and a big flip as you say to NEG NAO/AO and a SSW would be great.

Edited by Derbyshire Snow

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Whilst I agree a colder W/NW,ly is possible towards the end of the month, I do have one major concern for most of us with the exception of Scotland.

The GEFS ensembles suggest pressure will remain relatively high to our S.

prmslMadrid.pngprmslParis.png

So my forecast for the end of Jan/early Feb would be that the current mild spell will be replaced by temps returning to nearer average in the S and slightly below for Scotland where snowfall is possible on higher ground. Remaining unsetttled for all areas though.

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22 minutes ago, Severe Siberian icy blast said:

To be honest your getting to sucked into the models.  

We are not in "present zonal weather" we have had the first day where temps have got to 'normal' values .  So any predicted zonal weather at present is just that , predicted . It hasn't actually happened . 

I'm not sure how long we will be in this for . The models say 10 days or so , but I think maybe 7 days . I think another day or so and things will suddenly move forward ,  the last 2 days of the month to flip to Neg NAO/AO

well, no question we are in a zonal pattern for the next 7-10 days, that's pretty much nailed on. But whether we need a ssw or not, I'm not convinced, although It would certainly be a bonus.

i think Todays models, to sum up, have been ok. Bit like going to a cup match away from home that you know you should win, but your 2-0 down at halftime and you nick a late goal and get a chance in the second leg because of the away goal. 

There is hope, the signs are there, and all the background signals appear to favour us, let's relax for 7 days and remain positive, because we are still very much in it. 

 

image.png

image.gif

Edited by karlos1983
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12 minutes ago, Nick F said:

NOAA CPC 8 - 14 day H500 anomalies now shows the 'sausage' of low heights just to our north extending east into Scandi and the strong Wly flow across the UK. 

image.thumb.gif.58a2952364e4f7148236d16e

but note also the cross polar ridging over the pole between west Canadian and Kara highs, which is clearer on the 12z GFS v EC height comparison:

image.thumb.gif.520b87efa70c68c32fcb125c

So after a brief return to more a +ve AO, falling back to -ve again as we enter early Feb? NAO staying +ve though for a while as those southern Euro +heights continue to be forced.

I think these signs from the models of the trop vortices gradually  displaced from the Arctic can only be a good sign for Feb prospects, so we are perhaps seeing one last gasp of the Greenland PV and Atlantic storminess for a few weeks before blocking returns.

 

You know what Nick, I was just about to post the very same chart but say that for once in my life there was just no way you could spin it into something positive, and there you go, you managed it! ☺

It has to be said though, for an D8-14 day chart only to be offering a sniff of something, say, at D20-D30, isn't a good position to be in as the last week of January approaches. 

And there's absolutely no spinning this one, the ECM ensembles for London. Lost my gloves this morning on the way to work, I won't be rushing to buy a new pair though

http://www.weathercast.co.uk/services/ensemble-forecast.html

(sorry my machine not letting me post pics)

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4 minutes ago, karlos1983 said:

well, no question we are in a zonal pattern for the next 7-10 days, that's pretty much nailed on. But whether we need a ssw or not, I'm not convinced, although It would certainly be a bonus.

i think Todays models, to sum up, have been ok. Bit like going to a cup match away from home that you know you should win, but your 2-0 down at halftime and you nick a late goal and get a chance in the second leg because of the away goal. 

There is hope, the signs are there, and all the background signals appear to favour us, let's relax for 7 days and remain positive, because we are still very much in it. 

 

image.png

There's no way you can say zonal for 7-10 days is nailed . So when the models were showing high lat blocking after t144 was that likely to happen ? No one can say . Whilst we are entering a zonal spell , we simply don't no when the mods will pick up a pattern change . Like you said the background signals all point to a cold Feb , so let's enjoy watching the pattern unfold .  

Let the models settle down and once we are 2 days into it we can then start looking for a quicker response .

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I do live in hope, but I must say a lot of the "looks promising" posts in here, including the more technical ones, do remind me very much of the first few days of Feb last year as we were leaving behind what turned out to be, for the south anyway, the only few days of noteworthy cold we had all winter long. Never lost the hope, but always bear in mind there might be a very good reason the models aren't showing any particularly cold spell coming up!!!

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8 minutes ago, Severe Siberian icy blast said:

There's no way you can say zonal for 7-10 days is nailed . So when the models were showing high lat blocking after t144 was that likely to happen ? No one can say . Whilst we are entering a zonal spell , we simply don't no when the mods will pick up a pattern change . Like you said the background signals all point to a cold Feb , so let's enjoy watching the pattern unfold .  

Let the models settle down and once we are 2 days into it we can then start looking for a quicker response .

You might be right ssib, but the models have been pretty consistent the past few days about the next week being predominantly Atlantic Zonal. I'm not seeing anything to suggest that will change *yet, before next weekend at least. Of course that could change, but I can only comment on current output. Peace!

beleive me, I'd like to be wrong. And I'm still positive about the rest of winter. Just not the next 7-10 days lol

Edited by karlos1983
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4 minutes ago, karlos1983 said:

You might be right ssib, but the models have been pretty consistent the past few days about the next week being predominantly Atlantic Zonal. I'm not seeing anything to suggest that will change *yet, before next weekend at least. Of course that could change, but I can only comment on current output. Peace!

Agreed, models here and in US show no indication of this jet stream weakening and the ever present slug  is hard to move now it seems to be getting established . Thats what the current models show and predict, but after the weekend you never know. Interesting weather though, better than a meandering high stuck over the UK for weeks on end 

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I cant be sure if this has been posted today but an interesting video about the prospects for the rest of winter... 

colder northern europe , wetter southern europe.. thats smells of a - NAO 

and even some pictures of knockers daffs thrown in ... 

http://www.bbc.co.uk/weather/features/35375096?ns_mchannel=social&ns_campaign=bbc_weather&ns_source=twitter&ns_linkname=news_central

i also thought it was good educational information for joe public too :)

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4 minutes ago, Severe Siberian icy blast said:

There's no way you can say zonal for 7-10 days is nailed . So when the models were showing high lat blocking after t144 was that likely to happen ? No one can say . Whilst we are entering a zonal spell , we simply don't no when the mods will pick up a pattern change . Like you said the background signals all point to a cold Feb , so let's enjoy watching the pattern unfold .  

Let the models settle down and once we are 2 days into it we can then start looking for a quicker response .

Agreed on this, there does seem reasonable doubt at 7 days which could suggest a change to a more NW flow. I have been trying to post the 18z ensembles but for whatever reason I can't. By the 26 / 27th though there is a split which could indicate a slightly different outcome to currently modeled is coming. I tend to work on the lines of when high pressure is shown at higher latitudes (above the Azores for example) regardless of where this is shown it is possible that this could happen. The likely location for where it ends up though get's decided normally closer to the time. 

Based on what has been modeled in the last few days, strat forecasts and bias employed by most models I do agree with others that early Feb could see a different outcome to what is currently shown.

I do see a mid Atlantic ridge forming within the next 10 days and hope (as it is not currently modeled) that this ridge will be sufficient in strength and latitude and not blown away by any remnant of vortex left over Greenland pushing the jet stream straight west towards us.

By the weekend we should have a better glimpse of what could potentially be coming in the next 2 weeks, but based on what has been shown by the far more experienced posters like Tamara (not the only one mind you) I am certainly not writing off any potential for a colder last 1/3 of winter.

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1 hour ago, Singularity said:

Mike Ventrice tweeted this morning that the El Nino has become more central based, which is a good thing for encouraging the eastern Pacific and U.S. pattern to back west, taking any residual Canadian vortex segment with it - far enough to allow more in the way of high pressure NW of the UK but unlikely to be so far as to encourage a west-based NAO.

So many pieces of the puzzle seem to be falling in favour of a notably cold spell being the dominant feature of Feb 2016 that I'm having trouble accepting it without my brain shouting nonsense such as  'Sod's Law' at me.

 

Anyway, I believe key thing to look out for in terms of model trends for the final week of Jan is reductions in the strength of the Azores/Euro high which are possible given the likelihood some overestimation of the short-term AAM drop by the models.

The bigger changes such as troughs diving into Europe and marked height rises to the NW become more plausible for the output covering the first week of Feb. That's the optimistic end of the timing while the pessimistic end is third week of Feb... a bit of wiggle room as usual and I for one am hoping we get there sooner rather than later else I'll be needing some exceptionally cold air to retain the majority of snow cover through daylight hours. I'll do my best not to let this influence my judgement on here, of course! :snowman-emoji:

We're getting there (1.2 is now 1.2 lower than 3.4)  but when you consider atmospheric lags and the fact that the gap may be not be sufficient anyway, it's unlikely that this will deliver.

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1 hour ago, CreweCold said:

Trop vortex done for....

It'll have another go at a Greeny high/mid Atlantic ridge from here...

npsh500.png

Edit: GFS FI wants to faff around with vortex spin-offs which preclude further ridging attempts

h500slp.png

Only delaying the inevitable though!

How can you prove that though?? 

Leading newbies s on,explain why?

Alot of people guilty of posts like this but mods delete the less contributral ones.Big shame for bot the in crowd.

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