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Model Output Discussion - The Start Of Winter


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Yes its the new ECM. Lots of amplification bias in FI so will throw up some stunning charts if its current output is a trend. Its new so I would not put too much faith in it, especially in the last 6 hours where it has thrown up two totally different synoptics in its two runs. I am sorry but that does not garner faith. I will stick with the GFS Op as I know its foibles.

 

The GFS P keeps a cold upper flow from D7 to D16 with lots of interest.

 

Sticking with the GFS op is like wearing a pair of shoes that are falling apart, whilst a new pair is stuck in the wardrobe, it doesn't make sense. Seriously, why (apart from the drama it provides by its wild swings) would you stick with the old op?

 

The parallel is better, that is verifiable. Not as good, yet, as the ECM but it was getting there and recent tweaks will be attempting to close the gap even further,

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A few of you have asked today about rationale for the (tail-end of) UKMO latest 30-day outlook. There is, of course, a dedicated thread elsewhere for this but I'll just confirm that GloSea5 output rem

Thanks for this Barry   You are however wrong on both counts you suggest :   1) I have explained in extended detail, as much as I am able, the progress of the patterns thus far from autumn (see firs

Hopefully a timely interjection, but UKMO caution (again) that medium range NWP may not be adequately reflecting ultimate broadscale outcome. First tentative signs emerging, they suggest, of *possible

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Addition to my earlier post: in summary, UKMO note very little support "as yet" for the deepening frontal depression in 00z EC DET (= circa 10% ENS) and ditto for severe wx seen in GFS-P. However, developments remain under close scrutiny, obviously, given "...natural interest in festive period wx".

Understandable update, seeing that GFS-P cold is far out in la la land.

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gfsnh-0-384.png?6

Not quite the fireworks of the 00Z, but the 06Z(P) is the best chart yet for a prolonged cold spell. The block shown above could steer depressions to the south of us for some time - and possibly 1947 style snow upon snow upon snow. Just one FI run, of course, so nothing to get too excited about, and it just shows how far we are from knowing where this is going after Christmas Day just yet.

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gfsnh-0-384.png?6

Not quite the fireworks of the 00Z, but the 06Z(P) is the best chart yet for a prolonged cold spell. The block shown above could steer depressions to the south of us for some time - and possibly 1947 style snow upon snow upon snow. Just one FI run, of course, so nothing to get too excited about, and it just shows how far we are from knowing where this is going after Christmas Day just yet.

Not really new to the Forum I have been lurking round for some time but never posted. Would it be possible to explain why that chart indicates prolonged cold. There does not seem to be any Greenland blocking and the lower pressure over that area and the mid Atlantic seem to be vast by comparison with the high to the NE of the UK. So I would have thought the high to the NE would fill quite quickly. Could have got this completely wrong so would welcome some guidance. :cc_confused: Ta

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That's based on the GFS(P) 00z having a fair bit of lying snow at the time from the storm it showed on the 28th

uksnowdepth.png

 

Not sure exactly how much though as there doesn't seem to be a scale bar anywhere

 

Will fix that, not entirely sure why it's disappeared!

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I think with the pattern change likely now to happen early January (IMO), the next week should get some decent FI charts The warming in the strat should hopefully displace the vortex by the start of 2015 so there will be cold moving towards mid-latitudes. Whether it all goes to the US as per usual is anyones guess.

 

The ECM 2m temps for their ensembles: post-14819-0-21222200-1418817576_thumb.g

 

They show the cold uppers heading our way from about Christmas Eve. It is a sustained 4-5 days on average at the moment so if we can get a decent pattern by then there could be some interest.

 

The GEFS are relatively flat from D12-16 with the Atlantic ridge being shown variable amounts of longevity. The ones that keep it the longest rely on an upper level low or upper US-Atlantic trough to support the heights. eg the Control:

 

post-14819-0-79054400-1418817867_thumb.p

 

Unlikely in my view. D16 mean and the PV lobe is back home in NE Canada, its current location: post-14819-0-75275700-1418817959_thumb.p

Edited by i'm dreaming of...
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The 6z para looks surprisingly like Jan 2013 and how that started with weak heights north allowing cold uppers to flood from the east with trough rising up against them.

 

I reckon if that run continued they'll much the same.

Edited by SN0WM4N
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The output is pretty consistent upto the weekend. It's the finer details that will get nailed down for Xmas day itself this weekend. All, in all, it's still looking "Very promising" for Xmas day, boxing day and perhpas Xmas eve for some.  

 

We need to look to the Eastern Seaboard off Canada this weekend. What happens here is going to determine what kind of cold snap this will be, be it fleeting, sustatined or epic builder.  

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IDO it may be worth revisiting the fact you post the D16 mean every day & have said EVERY day that in your view there would be no cold, Its actually quite likely that if you keep posting the 16 day mean you will overlook EVERY cold spell for the UK this Winter......

Pretty much like you are this one.

 

the Ensembles for the NW part of the UK are already up to 5-6 days sub -5c.....

 

S

Hi Steve - The US (NE) looks like going into the freezer end of next week with heavy snow likely...how do you think if at all this will effect the BI?

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IDO it may be worth revisiting the fact you post the D16 mean every day & have said EVERY day that in your view there would be no cold, Its actually quite likely that if you keep posting the 16 day mean you will overlook EVERY cold spell for the UK this Winter......

Pretty much like you are this one.

 

the Ensembles for the NW part of the UK are already up to 5-6 days sub -5c.....

 

S

Hi Steve - The US (NE) looks like going into the freezer end of next week with heavy snow likely...how do you think if at all this will effect the BI?

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Some cold looking GFS charts around Christmas onwards but i would like the ECM more on board.

I am with Nick S when he posted earlier today regarding the west positioned Atlantic ridge, leaving the UK very much on the edge of the coldest air.

The amplification of the jet over NA and the sharpness of the Canadian trough seems less impressive on this run and consequently so does the downstream Atlantic ridging which keeps the jet from getting far enough south over the UK.

post-2026-0-81577600-1418820081_thumb.gipost-2026-0-34889200-1418820089_thumb.gi

 

A look at the ECM mean height anomalies for now and day 10  and there is no doubt a move in the NH pattern coming

post-2026-0-75192900-1418820548_thumb.gipost-2026-0-57991300-1418820557_thumb.gi

 

those Greenland blues gone replaced by the ridging and the low heights towards Scandinavia.

 

The problem is the flat looking Scandinavian trough and the non-removel of high anomalies to the south this would at least  delay cold digging in with maybe just parts of Scotland seeing snow on this set up.

 

Of course time yet for these details to change either way but i can see why the MO are not yet inclined to jump on board.

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Think we all need to take a step back to be honest. Talk of cobra meetings taking place are well wide of the mark. Looking at the gfs 06z away from scotland we are looking at nothing much apart from a few fleeting cold snaps. Yes we may well be seeing a northern hemisphere pattern change taking place. But snowfall this side of xmas is very rare for the uk apart from dec 2010 of coarse.And until the mo come on board we should all be very sceptical of the eye candy runs in fi. So lets see what the next few days bring. And if were still seeing similar output around next monday then we maybe onto something. Until then i will watch ian fergusons updates with intrest regarding the met office musings.

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Think we all need to take a step back to be honest. Talk of cobra meetings taking place are well wide of the mark. Looking at the gfs 06z away from scotland we are looking at nothing much apart from a few fleeting cold snaps. Yes we may well be seeing a northern hemisphere pattern change taking place. But snowfall this side of xmas is very rare for the uk apart from dec 2010 of coarse.And until the mo come on board we should all be very sceptical of the eye candy runs in fi. So lets see what the next few days bring. And if were still seeing similar output around next monday then we maybe onto something. Until then i will watch ian fergusons updates with intrest regarding the met office musings.

 

Your luck just might be in Terrier. .

 

UK Outlook for Thursday 1 Jan 2015 to Thursday 15 Jan 2015:

The most likely scenario for the coming New Year is for a continuation of unsettled, and at times, windy weather coming from the Atlantic with the wettest weather probably across western parts of the UK, and eastern parts most likely to see the best of any dry weather. Temperatures are generally expected to be around average for the time of year. There is a chance of some overnight and morning fog in places as well as a local frost - this will be most likely across northern areas where there is also a chance of some snow on higher ground. However, there is no strong signal in weather patterns during this period, with a period of colder weather possible too.

 

 

Considering that yesterday any reference to cold had been removed and certain people were fretting, I will certainly take this update.

Edited by The Post-modern Winter
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