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Model output discussion - 20th Feb onwards

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if u really really want a note worthy cold blast from now into march then split vortex blocking into Greenland!

and vortex segment to our ne dropping down the north sea into south eastern Europe with air coming straight from the arctic no topplers just vortex to our east and blocking to our west into the north  atlantic  and Greenland and holding there without being flattened by the vortex and lower pressure systems.

then we get a straight sustained arctic flow and I suspect a sustained north easterly flow would do the trick to cold sustained air from Siberia but this is certain not what any of the models show.

 

forget easterly forget scandi heights but I do think Fergie weather and the longer range models have done exceptional this season and its worth taking note I do think we will get an arctic blast but nothing sustained until the features ive suggested set up.

but I'm with knocker close but no cigar.

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12 hours ago, January Snowstorm said:

We learn something small every year and the noaa anomaly charts are my lesson for 2016. Jh often mentions them and rightly so.

In what's been an appalling year for model accuracy they have been the shining light.

 

 

12 hours ago, Long haul to mild said:

I've become a bit of a convert to those anomaly charts this winter as I think they are good at picking out the mid range overall pattern.

good to see people taking note of these, ive been on here 10 years and ive seen new fads for some databases heralded as 'the' one come and go - but johns findings on these charts are proving time and time again to be the best indicator of the likely pattern for the timeframe they cover.

i view the noaa charts first, and when they are consistent over a few runs they are very accurate. this helps those of us who want to know what the most likely outlook will be. it irons out the vagaries of the ops - so wont lead you up the garden path like the ops can do.

in saying all that, im not so sure that the current ones are immune from uncertainty as the 6-10 day chart has changed to a more 'flat' run whilst the 8-14 day chart is holding on to troughing to our near east. not sure thats a plausible evolution , maybe low confidence for these? 

edit - just seen johns already mentioned this...



 

610day.03.gif

814day.03.gif

Edited by mushymanrob

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14 minutes ago, mushymanrob said:


in saying all that, im not so sure that the current ones are immune from uncertainty as the 6-10 day chart has changed to a more 'flat' run whilst the 8-14 day chart is holding on to troughing to our near east. not sure thats a plausible evolution , maybe low confidence for these? 

edit - just seen johns already mentioned this...

 

I looked at that 6-10 chart last night and also thought it distinctly odd. No reflection of any intrusion at all from the Azores HP in the isohypse. Await tonight's with interest but I'll wager it wont be so zonal.

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13 minutes ago, fergieweather said:

The largest cluster from 00z EC gives a fair representation of expected outcome towards mid-March. From around then into late March, northern blocking becomes extensive in longer range suites (conspicuously so in yesterday's EC Monthly) and similarly reaches on into (at least early) April in GloSea5, maintaining the colder than normal theme. Note the risk of this outcome was previously suggested in the Feb issue of UKMO 3-monthly probabilistic assessment, before the EC Monthly support emerged.  

Screenshot_2016-02-26-09-35-53-1.png

that chart looks like april 1974 - we had days of stratus off the north sea , the west fared best as they had sunshine and if the cloud burned back we (in derby) joined the west in warm sun.

at least it was dry.

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5 minutes ago, BarnetBlizzard said:

GFS 6z shows second low turning up a lot quicker with better heights behind it. Could be a good run this one. 

I was thinking that myself but being a that good few runs have been showing a belting lately, I wonder if I would just rather see consistency rather than something different , its not like they have been short of Northern blocking deeper into FI either.

Edited by feb1991blizzard

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1 minute ago, feb1991blizzard said:

I was thinking that myself but being a good few runs have been showing a belting lately, I wonder if I would just rather see consistency, its not like they have been short of Northern blocking deeper into FI either.

A consistent upgrade would also be nice! What I like about this run is that the upgrade is occurring around day 5-7 rather than day 10-12, therefore has less time to downgrade.  Of course the upper air temps would be a bit lower in an ideal world but with slack winds at times and heavy precip about then snow somewhere would be more likely than not.  

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5 minutes ago, BarnetBlizzard said:

A consistent upgrade would also be nice! What I like about this run is that the upgrade is occurring around day 5-7 rather than day 10-12, therefore has less time to downgrade.  Of course the upper air temps would be a bit lower in an ideal world but with slack winds at times and heavy precip about then snow somewhere would be more likely than not.  

Yes - better run synoptically definitely so far but a very slight downgrade on already marginal uppers, slithers of -6c got into England on the last run, now above -4c in the south, that difference for your neck of the woods guarantee rain.

 

EDIT : Ive just seen you live in York now, I was thinking Barnet in North London.

Edited by feb1991blizzard

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12 minutes ago, BarnetBlizzard said:

GFS 6z shows second low turning up a lot quicker with better heights behind it. Could be a good run this one. 

For those that can't see the charts....

0Z around day 7

gfsnh-0-186.png?0

6Z at same time

gfsnh-0-180.png?6

But as @feb1991blizzardsays, in many ways consistency would be preferable to 'upgrades'.

 

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4 minutes ago, feb1991blizzard said:

Yes - better run synoptically definitely so far but a very slight downgrade on already marginal uppers, slithers of -6c got into England on the last run, now above -4c in the south, that difference for your neck of the woods guarantee rain.

Barnet blizzard could be a euphemism for severe dandruff... After all, his location is mentioned as York.

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1 minute ago, Steve C said:

Barnet blizzard could be a euphemism for severe dandruff... After all, his location is mentioned as York.

Yes ive edited now accordingly.

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Just now, Steve C said:

Barnet blizzard could be a euphemism for severe dandruff... After all, his location is mentioned as York.

Made this account 8 years ago! I now live somewhere else!

I would not say -4  to -5 guarantees rain, especially with slack winds and heavy precip. Whether it settles on wet ground etc is another question. 

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Just now, BarnetBlizzard said:

Made this account 8 years ago! I now live somewhere else!

I would not say -4  to -5 guarantees rain, especially with slack winds and heavy precip. Whether it settles on wet ground etc is another question. 

Sorry and agree, especially if precipitation is constant.

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No let up of the cold theme from the 6z, With a nice Northerly flow showing as we head into Spring giving some severe frosts for the North and snow showers aplenty pushing South. 

a.pngb.pngc.png

Edited by Polar Maritime

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1 hour ago, fergieweather said:

The largest cluster from 00z EC gives a fair representation of expected outcome towards mid-March. From around then into late March, northern blocking becomes extensive in longer range suites (conspicuously so in yesterday's EC Monthly) and similarly reaches on into (at least early) April in GloSea5, maintaining the colder than normal theme. Note the risk of this outcome was previously suggested in the Feb issue of UKMO 3-monthly probabilistic assessment, before the EC Monthly support emerged.  

Screenshot_2016-02-26-09-35-53-1.png

Yes I was looking at the means and although temps a tad under average it looks dry and fairly settled. I'll settle for that at the moment providing we get a nice warm up after. :)

The key question may be sunshine hours.

Edited by knocker

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Some very nice synoptics on show today which in mid winter would be causing a lot of excitement in here.

However it continues to look marginal for snow, although we see high pressure trying to ridge towards Greenland its unable to hold for long enough to tap some much colder uppers.

I think it would be a bit premature however to rule out some more favourable upper air getting into the UK because the MJO response might still not be fully showing in the outputs.

You only have to see the marked change the ECM has shown between todays outputs and those a few days back to see that theres been a big increase in amplitude.

We'll see over the next few days whether the outputs can manage to tap some deeper cold. Of course we have in the past seen snow in March without deep cold where other factors have been favourable but so far every marginal set up in the last few weeks seems to have always gone the wrong way.

 

Edited by nick sussex

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Well, well, well. 06z ensemble 2m tempst2m_London.png for London still showing a brief milder blip and then cold all the way through. More chilly days to make up for the mild damp horror of much of this winter.

t2m_London.jpg

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The ecm 10-15 anomaly this morning has a weakening ridge western N. America with ridging mid Atlantic towards Iceland and trough North Sea down into Europe. Thus the upper flow veering somewhat and the HP becoming more influential so though the temps remain depressed slightly it would herald drier and settled conditions. Rather dependent on the amplification of the ridging as systems could still whip SE around the HP bringing periods of wintry weather if this isn't robust which I suspect will be the case.

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It looks like meteorological Spring starts on a rather wet note as GFS shows the milder wedge of Atlantic air moving in.

The.thumb.png.9111936ee6fbe6972d1c09a2be56d079986af56_viewimage(2).thumb.png.3f9

Temperatures on Tuesday maxing out into double figures down south and this may prove the exception for sometime as we see the jet dig south during next week.

56d079daecad9_viewimage(3).thumb.png.406

So it looks like being quite a brief warmer spell as the colder air from the north west soon replaces it with snow returning over Northern Scotland.


 

 

 

 

Edited by phil nw.

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That incoming Northerly in GFS FI is going to be an absolute snorter.

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