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phil nw.

Winter Model Discussion 12Z 22/1/13 onwards.

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Here we are then a new thread ready for the 12z Model runs.

The cold spell continues for a few more days which for many has been perhaps more notable for snow than excessive low minimums.

However this has been a fascinating pattern too with the UK in the battle zone where the Atlantic systems have been continually disrupting against our cold block creating several snow events in different parts of the country.

It looks like this pattern will come to an end as the block is expected to finally relent by the end of the week.

The Fax at T84hrs showing the Atlantic knocking on the door.

post-2026-0-58403000-1358865906_thumb.gi

This will introduce a more Westerly flow into the UK beyond lifting temperatures after what will have been approx 2 weeks of cold for many.

Let`s see what the 12z runs have in store.

Please keep your posts polite and about model outputs-if members feel emotional over the charts rather than objective then please go here-

http://forum.netweat...n-ramp-go-nuts/

OK on we go.

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I've really enjoyed this cold spell of weather...and while maybe the cold has not been that dramatic, nor the overall amount of snowfall, the time it has spent snowing is one I can find few winters to compare to, and i'm sure my kids will look back on it in year to come and remember it as a "real winter"

And strangely enough, I remember the approach of it gathering pace (though to be fair it seemed to take ages) with the kind of pessimistic comments that TEITS and SM are coming out with now!!!

i remember it so much because it was odd for me to feel an enthusiastic optimism for something which seemed to go at odds with what the both of them were saying...as I regard them as two of the most informative people on here.

You must i've got my posts mixed up with someone else because prior to this cold spell I was full of optimism. Infact on the 5th Jan I posted on my Facebook page about the coming cold spell and since then I have recieved some very complimentary responses from friends and family. I did have a very negative view towards the model output over the xmas period but my mood changed at the beginning of Jan.

Like I said earlier im not ruling out a change in the first week of Feb. However what I am saying is the model output from +144 to +240 is very poor. My main disagreement though is with those members who seem to think the milder SW,lys won't occur next week. We need an epic turnaround from the models for this to occur which in my opinion is very unlikely.

This cold spell has been epic in my location I will add. So far 4 snowfalls, 8 inches of lying snow, -9C this morning. Considering the relatively weak synoptics its been incredible. However the output has soured this a little because back in late Dec, early Jan I was expecting far better synoptics being shown for late Jan than the dreadful output im seeing at the moment.

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The first of today's 12'z runs is almost complete from GME there is likely to the some transitional snow on Friday as a band of rain moves west to east behind the band of snow milder air will slowly move in with flooding a real threat into next week

Thursday morning we still have cold air over the UK

gme-1-42.png?12

By Friday this gets pushed further east

gme-1-66.png?12

By Saturday the milder air is moving ever closer

gme-1-72.png?12

gme-0-72.png?12

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Could be some big u turns though dave with SST coming onto the models.

what do you mean sst coming onto the models?

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GFS is showing an unsettled and eventually milder weekend tonight with winds coming in from the Atlantic

gfs-0-96.png?12

gfs-1-96.png?12

gfs-2-96.png?12

By 19:00 the mild and wet weather sweeps across the UK

gfs-0-102.png?12

gfs-1-102.png?12

gfs-2-102.png?12

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post-17488-0-60294400-1358870502_thumb.j

I think the East won't be beat as easy as is being currently modelled :)

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post-17488-0-60294400-1358870502_thumb.j

I think the East won't be beat as easy as is being currently modelled smile.png

The atlantic winning and becoming milder now has good agreement and looks like happening on the weekend. Only thing that is less certain is that how it breaks down, how mild it gets and how long it lasts but the cold spell is now coming to an end, and its been a decent one for many areas. Now we search for the next one, plenty of signs in GFS FI but as Dave says, 96-240 is poor currently but this doesnt mean to say we won't see cold returning the first few days of February and the MetO outlook certainly hints at cold returning. If you do not like mild, maybe it is best to take a break for a few days but not too long because i think we will see some more blocked/cold charts reappearing in the near future. GFS last several ops have hinted at this and it was a pretty decent GEFS 6z suite so we will see, will the 12z GFS continue the GH theme in to FI? I think so.

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Doesn't it annoy you how the models are so consistent when the weather is from the west! Run to run consistency within 144 at the moment is superb. (Or disgusting, looking at the t120 chart!!)

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GFS is showing an unsettled and eventually milder weekend tonight with winds coming in from the Atlantic

gfs-0-96.png?12

gfs-1-96.png?12

gfs-2-96.png?12

By 19:00 the mild and wet weather sweeps across the UK

gfs-0-102.png?12

gfs-1-102.png?12

gfs-2-102.png?12

Yes very true - We can'y deny now that the Atlantic is going to finally power through the block, although I am not convinced it will last before heights will begin to rise towards Greenland. What needs watching though is there could be a major snow event/breakdown for Wales and North West England on the cards as the Atlantic comes through as current models suggest. Albeit turning back to rain (How much of this will be rain is anyone guess) but it's worth keeping an eye on the last snow event before it becomes Milder.

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Yes very true - We can'y deny now that the Atlantic is going to finally power through the block, although I am not convinced it will last before heights will begin to rise towards Greenland. What needs watching though is there could be a major snow event/breakdown for Wales and North West England on the cards as the Atlantic comes through as current models suggest. Albeit turning back to rain (How much of this will be rain is anyone guess) but it's worth keeping an eye on the last snow event before it becomes Milder.

Yes a snowy breakdown is on the cards for many

prectypeuktopo.png

prectypeuktopo.png

During Saturday we then see rain falling

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UKMO has the last of the cold air leaving on Friday pretty much in line with GFS

UW72-7.GIF?22-16

UKMO also brings the deep depression in at the same time as per GFS

UW120-21.GIF?22-17

The big 3 all agree on this now and they all have it at around 940mb over the coming days its likely to ease slightly but its still going to be a windy and at times wet weekend

As that low clears away on Monday another one is winding up in the Atlantic ready to hit the UK

UW144-21.GIF?22-17

gfs-1-156.png?12

gfs-0-156.png?12

So after a colder spell we are now almost certain to see a return to a zonal pattern as we enter the final week of January

A mild dry start colder and snowy (for some) in the middle and it now looks like ending milder and wetter

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'long way back to cold from here' is a phrase I often see trotted-out, yet - time and time again - it feels like those who use it are setting themselves up. This season, we've seen record levels of entropy - confirmed by the professionals, and yet even against that background uncertainty, we see such certain, absolute and conclusive statements from amateurs?

My personal view, is that I'm not convinced NWP is entirely or, at the very least, convincingly representative of background signals; background signals which have the potential to significantly influence the output. My belief is that the current algorithms do not (yet) have sufficient capability to determine a variable which would be so at odds with what current NWP algorithms would logically and scientifically propose.

Therein, it's difficult for me to place any great deal of confidence in the current output; therefore I find it futile to make any claims - one way or t'other - regarding how patterns will evolve many days hence. That may seem to some like a boring position to take, but I just don't see how anyone could reasonably make a confident call, considering what we know to be a highly volatile situation.

By now I should hope many know my position; I'm all about the science, and my view of SSWs isn't one which is determined regarding whether we get cold or not - it's about testing the fundamentals of the hypothesis, so that we can better understand the atmospheric influence. To that end, in all honesty, I'm not the least bit bothered whether the net result is blazing BBQs or igloo building - irrelevant to me; what's important is developing algorithms which can tighter model cause:effect through the atmosphere.

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Just our luck- a displaced vortex from the Strato.warmings over the Atlantic side.

post-2026-0-42079400-1358872005_thumb.gi

all we can do is wait this period out and hope the transfer of the main energy moves across to Siberia without pausing over the Greenland area for too long..

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You must i've got my posts mixed up with someone else because prior to this cold spell I was full of optimism. Infact on the 5th Jan I posted on my Facebook page about the coming cold spell and since then I have recieved some very complimentary responses from friends and family. I did have a very negative view towards the model output over the xmas period but my mood changed at the beginning of Jan.

Like I said earlier im not ruling out a change in the first week of Feb. However what I am saying is the model output from +144 to +240 is very poor. My main disagreement though is with those members who seem to think the milder SW,lys won't occur next week. We need an epic turnaround from the models for this to occur which in my opinion is very unlikely.

This cold spell has been epic in my location I will add. So far 4 snowfalls, 8 inches of lying snow, -9C this morning. Considering the relatively weak synoptics its been incredible. However the output has soured this a little because back in late Dec, early Jan I was expecting far better synoptics being shown for late Jan than the dreadful output im seeing at the moment.

TEITS.... I can beat you on Facebook.... I posted on 30th December about the weekend after the following one being a whole different kettle of fish to the mild one coming!! And I reinforced it with a post on the on the 3rd Jan smile.png

...and in the model thread it might be argued that you took longer to come to the excitement table than others.....

name='Timmytour'] Posted 31 December 2012 - 00:35

GFS 18z is leading the way. So many similarities with 1947 is going to land us with the greatest similarity of all. This time the Easterly is coming with the pool of cold air already there and giving it the strength it lacked in the early part of December.

My my it's going to be cold after feeling so mild next weekend. And my my it's going to get busy in here again!!!! I anticpate we will be upto 25 pages by the end of tomorrow...contrasting with it taking a few days to get that far in the previous thread.

name='EYE IN THE SKY'] Posted 02 January 2013 - 10:19

Ian Brown, on 02 January 2013 - 10:03 , said:

Underwhelming is certainly the word, It’s hard to see what is going to shift this well established set-up of low heights to the North and the Euro High.

ECM extended ensembles don't exactly have me leaping for joy.

http://www.knmi.nl/e...E_06260_NWT.png

Really hope this is one of those periods where the ensembles are wrong and we see a big change in the operationals with the ensembles following.

Sorry everyone for my negative tone this morning but its getting tiresome looking out to F.I this winter. I know the potential warming in the stratopshere gives us hope but it means absolutely nothing if the potential isn't being shown on the likes of the GFS/ECM in the troposphere.

Sorry.....I know that is so so unfair air_kiss.gif

The point I'm making is that in 12 days time things can shift dramatically. It's worth me pointing out that, prior to this post of yours you were hitting the date 14th January as the beginning of a cold spell and providing reasoning for it....and to me that was bang on the money in the end.

My post was more from an optimism that what I was seeing in the models was the kind of mildness that reminded me of two weeks before the onset of 1947's weather! Hardly reasoned!

Tbh this time, if we do end up where the likes of GFS take us in T144 + i share your concerns about anything developing. This time around Fergie's not on here telling us about the SSW and what to expect....there doesn't seem the same anticipation among some of the meteorological professionals as appeared before.

I really do appreciate and value your input, as well as that of Steve Murr's, and i completely understand why there's a downbeat tone to your posts. But when I look for straws to clutch, this winter has already provided me with a downbeat TEITS and Steve Murr and there followed some weather gold! So that will be my straw this time :)

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'long way back to cold from here' is a phrase I often see trotted-out, yet - time and time again - it feels like those who use it are setting themselves up. This season, we've seen record levels of entropy - confirmed by the professionals, and yet even against that background uncertainty, we see such certain, absolute and conclusive statements from amateurs?

My personal view, is that I'm not convinced NWP is entirely or, at the very least, convincingly representative of background signals; background signals which have the potential to significantly influence the output. My belief is that the current algorithms do not (yet) have sufficient capability to determine a variable which would be so at odds with what current NWP algorithms would logically and scientifically propose.

Therein, it's difficult for me to place any great deal of confidence in the current output; therefore I find it futile to make any claims - one way or t'other - regarding how patterns will evolve many days hence. That may seem to some like a boring position to take, but I just don't see how anyone could reasonably make a confident call, considering what we know to be a highly volatile situation.

By now I should hope many know my position; I'm all about the science, and my view of SSWs isn't one which is determined regarding whether we get cold or not - it's about testing the fundamentals of the hypothesis, so that we can better understand the atmospheric influence. To that end, in all honesty, I'm not the least bit bothered whether the net result is blazing BBQs or igloo building - irrelevant to me; what's important is developing algorithms which can tighter model cause:effect through the atmosphere.

There is no doubt the models struggle with the affects that the ssw has on the troposphere, but why is that?

The models are human generated computers programmed by us and we are only beginning to understand the affects of the Stratosphere on the Troposphere, therefore until we understand the science how can we programme the models?

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But, as we all should know: saying that things can change is hardly all that useful, is it? IMO, true success will only come-about when reasons are posted at the same time as predictions?

Do the models know how to handle the effects of SSWs? I don't think so...Will a change to 'cold' weather seemingly appear of nowhere? Almost certainly...

But, other than that statement of uncertainty/entropy/chaos, who can say when??

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My personal view, is that I'm not convinced NWP is entirely or, at the very least, convincingly representative of background signals; background signals which have the potential to significantly influence the output. My belief is that the current algorithms do not (yet) have sufficient capability to determine a variable which would be so at odds with what current NWP algorithms would logically and scientifically propose.

You always talk of 'background signals' but don't really divulge into what they are.

Care to elaborate? It's hard to take your posts seriously if there's no real explaining of what signals you are looking at.

Thanks :)

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Now can we get back to talking about what the latest models actually show please everyone.

Thank you.

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Oh Dear. Spot the HLB: post-14819-0-10478500-1358875812_thumb.p

Dont worry, nor could I.

The SSW not showing much there!

Glad thats a T384 chart and worthless. I suppose its wait and see, and hopefully something wintry will pop up at short notice.

And no, there is nothing in the whole run that looks like cold is returning before mid Feb: T240: post-14819-0-77927700-1358876119_thumb.p

From past experience these zonal charts are 7/10 days min, usually longer.

Short ensembles suggest high confidence in above average temps from next week: post-14819-0-56776900-1358876270_thumb.g

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The heavy rain, saturated fields, and flooding isn't too good for them either!

http://www.wetterzen..._London_ens.png

your correct,but what wev'e had here is more than enough.we dont really flood as living on a large hill prevents it.sheep will become accessible again.

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A couple of points of possible interest before the inevitable change.

An area of snow tonight affecting some areas of SW,CS England,SE Wales and moving into the West Midlands later before fading away tomorrow-one to follow on the latest forecasts and radar..

post-2026-0-21856600-1358876724_thumb.gi

One last really cold night Thursday according to 12z GFS,especially over the snowfields-a continental flow,low dew points and the relative calm under the retreating block.

post-2026-0-07159600-1358876703_thumb.pnpost-2026-0-96116300-1358876711_thumb.pn

all combine to give a final fling before the milder Atlantic air starts to infiltrate the UK at the weekend.

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Some crazy NH patterns now evident post T300. like i said earlier, i doubt the boredom will last too long on here. let the manic depressives wear themsilves out and then the fun can start again !

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