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Paul

Model Output Discussion - Stormy Period Inbound...

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if ian reads this, is the extended eps mean/anomoly misleading re clusters. it looks like a pretty cold period to me days 10/15. are MOGREPS/GLOSEA not seeing it that way? the eps have been so consistent with this evolution to the euro trough.

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Looks like Northern Ireland going to take the worst of the midweek storm with gusts around 100 mph in the early hours of thursday unless gfs is over-doing it.

 

attachicon.gif60-515PUK.gifattachicon.gif60-289PUK.gif

I think ourselves and Scotland is taking this one on the kisser.

Storm was been modelled further to the North and the South but at two days out I don't think the GFS is going to be to far out.

Question of how big a mb drop will remain to be seen after event.

Bin day is Thursday as well if they can find it.

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I think upgrades are the name of the game from here on in. By the way, did BBC News Channel just play yesterdays extended forecast ?

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There was still a rather strong warming which would have led to a SSW, if the vortex had not already been split at the time. I think I said at the time that the SSW may not matter because of the volatility of the vortex this winter and that may just prove the case with the Atlantic and Pacific sectors possibly reversing in fortunes. The weakening of the vortex shouldn't be dismissed though Barry just because a SSW didn't occur.

 

I'm not dismissing it, obviously the vortex is nothing like it was last year and it being weak is certainly helping. There was just a few posts last week of people writing of weeks/months of the winter for cold because there was no SSW.

Edited by Barry95

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Right........................quite a few posts removed/edited....

 

If you like a post then hit the 'like' button and please don't clutter up the thread with 'hey, great post' one liners,

 

and secondly as always, please hit the 'report' button for posts that might be in breach of the forum guidelines and not reply.....let the site team deal with it, that's what we're here for

 

and thirdly, self moderation is the key to a happy thread!

 

cheers  :smile:

Edited by ajpoolshark

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I think upgrades are the name of the game from here on in. By the way, did BBC News Channel just play yesterdays extended forecast ?

Yes they did! lol

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I'm not dismissing it, obviously the vortex is nothing like it was last year and it being weak is certainly helping. There was just a few posts last week of people writing of weeks/months of the winter for cold because there was no SSW.

I know that you were referring to the number of people that think that a SSW is all or nothing for cold. Your right about the vortex being completely different to last year and it's a pity that we have not seen more in the way of cold considering. Seeing what was effectively 1/2 a SSW last week was very disheartening!

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Gfss still the same as the 12zs!! Parallel has that potential channel low further north maybe?

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To my untrained eye both the 18z GFS and p look better than 12z, low pressure further west more negatively tilted and better heights towards greenie.

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Yes,seems strange to see the GFS with the more amplified solution at 120 hrs.

 

gfs..post-2839-0-36846900-1421100705_thumb.pn  ecm..post-2839-0-35329300-1421100703_thumb.gi

 

 

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Righty-Ho. This can't pass without comment.

Below follow just a random snapshot of detailed medium range briefings from Ops Centre made in first days of Jan, looking towards what was then the 10-15d trend (and now current-short term) period. I will leave it to others to judge if my UKMO colleagues have got things "so massively wrong"....

Written 1 Jan: "The unsettled conditions continue into the trend period but with some evidence of increased meridionality in the upper pattern and so allowing for some greater space between systems and perhaps increased signal for some clearer/colder/showery conditions between."

Written 3 Jan: "Latest f/c output continues to indicate a continuation of the predominantly mobile, and often unsettled, theme, with periods of wet and windy weather interspersed with clearer/colder weather. Some EPS members continue to indicate the risk of very deep areas of low pressure crossing over or close to the UK at times, bringing the risk of locally storm-force winds mainly, but not exclusively to N’ern areas. A few of the more S’ly tracks (currently about 10% of members take lows across Wales and England) would allow the entrainment of colder air into these systems, with a lower risk of heavy snow developing. All output does allow for transient ridges, but the wavelength of the upper pattern is such that any drier/colder interludes would be short-lived, and there is no strong signal for any prolonged settled spells, or easing of zonality..."

Written 6 Jan: "The zonal, cyclonically biased spell looks set to continue for the majority of this period. Further very deep areas of low pressure are signalled to cross the UK at times, bringing the risk of disruptive weather with them, these in turn being driven by a powerful cross-Atlantic jet. Colder Pm airmasses (originally Pc airmasses with origins from N’ern Canada, though heavily modified) are likely to cross many parts between systems, bringing below normal temperatures, and a risk of snow/frost."

Need I go on?

 

 

Excellent but I don't remember seeing anything like that in official updates, the accent seemed to be more on dull and mild with brief colder showery interludes with plenty of wet and windy weather on official website. Where were these reports published please, I missed them unfortunately.

Can we get access to them, they seem much more detailed than official forecasts.

Edited by Mucka

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Sat night looks v interesting Sat night with channel low showing snow Midlands South.

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144 on the the gfs looks like and undercut is coming next frame. Easterly inbound on this run?

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Channel low on GFSP looking good for snow Sat night for the Midlands South. 18 hours or more of it!!!

Edited by Ali1977

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NICE GFS 18z op so far with low pressure disrupting West of UK.

 

gfsnh-0-150.png?18

 

Not far off a traditional, East meets West chart with a snowfest where air-masses meet.

 

GFSp looking nice too with snow for Central Southern areas and good amplification thereafter.

 

gfsnh-0-132.png?18gfs-2-126.png?18gfsnh-0-150.png?18

Edited by Mucka

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I know that you were referring to the number of people that think that a SSW is all or nothing for cold. Your right about the vortex being completely different to last year and it's a pity that we have not seen more in the way of cold considering. Seeing what was effectively 1/2 a SSW last week was very disheartening!

 

Yes I agree this is certainly not a blocked pattern but it's trend has taken the colder route at each key junction so far which makes it interesting.  It clearly to demonstrates that for a lot of the country wintry output is possible without a SSW event or a HLB.  

 

What I puzzle over is the impact of the minor warmings we've seen in the strat and how they relate to the trop in any predictable way.  They've certainly impacted the PV even if it has been quick to reform.

 

The other key input is the Azores high and it's westward retreat with some amplitude north. It's a significant change as we move through January.  

 

Of course we have the low pressure front tracking through Scotland on Thursday and and bringing very strong winds to areas further south.

 

All in all given the variables in play I've been surprised  how little variation there has been between control and ensembles on the GFS and between GFS and other models.

Edited by Trom

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Amazing how the met office with their multi million pound computers and hundreds of Millions from the taxpayer have got it so massively wrong

They forecast westerlies and South westerlies for the next couple of weeks, when it is very clear that the UK is heading into the freezer in a way not seen for a couple of years

 

I think you must either be looking at a different set of models to me, or talking about some other met office - cos there is little to no disconnect between what is happening in the next 10 days and what the UK met have forecast. I dont see any freezer - but there will be some chilly PM air which will give snow to high ground at times. I think we probably had colder weather 3 weeks ago?

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The uppers at 150 on the GFSP are not quite as good as the 12z.  Still not too bad, colder temps inbound?

 

gfs-1-150.png?18

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Jheeez gfs keeps upgrading these slider lows!! If they are still there tomorrow am gona start to think we're on to something here! !

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Tbh, I think Exeter have covered themselves as they mention there could be frost and snow. Clearly, several clusters to play out next week. I have already nailed my colours to the mast but then I won't get misquoted by Nathan rao so the stakes are non existent for me.

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Channel low on GFSP looking good for snow Sat night for the Midlands South. 18 hours or more of it!!!

138-780PUK.GIF?12-18

........with it creeping south:

150-780PUK.GIF?12-18

 

.........one days these maps might come out right! ;)

Edited by stratty

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138-780PUK.GIF?12-18

That doesn't look like 18 hours of snow!! :-/

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Very encouraging to see the pattern being backed West on the modelling. Hope this isn't just a GFS pub run, hic.

Big day model watching tomorrow for coldies.

 

gfsnh-0-168.png?18

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