Model Output Discussion

[LomondSnowstorm]

Frustrating model output this morning just when you thought perhaps we'd begin to see the easterly firming up! It doesn't look quite as good as yesterday but not all that disimilar to yesterday morning, with the GFS still going for it, the ECM getting there as well but the UKMO still refuses to budge. Clearly there is too much uncertainty to look too far ahead with any confidence but I'd still back the block in the long run - in spite of the UKMO's persistence it is possible that it is just wrong. Still, the road to an easterly looks less clear this morning.

LS

[PB22]

Bu Paul surely it can hardly be classed as a 'trend'. If by this time tomorrow the models et al have continued in this vein then I would have to agree.

I am concerned, and said so yesterday, about the UKMO. It's on to something and has been toying with more energy in the Northern arm for a few runs now. Other models are starting to look at this as well. I have been saying that we should expect a mild interlude prior to a continental feed but what a couple of the models are hinting at is sending the LP's in over the top which would potentially spell disaster, personally I'm not convinced by this evolution though. The ens are not looking great this morning either though.

These are the 180hr and 174hr charts from yesterday's extreme 18z and this morning's tamed down version on the 00z...

Hi s4lancia, I'd suggest that the trend on the UKMO model is certainly away from any potential easterly based on the last three runs by that particular model, and that the other models are slowly edging towards the UKMO. I'd certainly agree with Nick S's comments above and that tonight could be last chance saloon.

[BLAST FROM THE PAST]

You have to laugh, or cry, at the models sometimes! Just as the GFS produces an almost identical medium term run to the 12z ECM with a battle royal with a block to the NE and weather systems trying to push up from the SW, the 00Z ECM totally ditches the idea and blows the block away!

UKMO is even worse, in fact is miles away from cold at +120 and +144.

There is a massive scatter on the GFS ensembles for London, but overall no where near as promising as they were.

That t144 chart on the ECM seems just plain wrong. Why? because at T168 it shows the block suddenly becoming dominant again. I strongly suspect that is has shunted too much energy too far north east because from 168 onwards it ditches the idea and a cold SE'ly feed sets in. T120 is still FI.

BFTP

[Blizzard_of_Oz]

This may not be the right thread but look at this from Ian Fergusson's Blog.

Remember February 2009? The deep snow that brought London and much of the southeast to a spectacular standstill? It's by no means impossible that we'll see similar weather establishing across the same parts of the UK in a week or so.... and possibly more widely, too.

Usually, I restrict my blog to matters of forecast interest within a few days of the here-and-now, but the growing signs - and growing forecast model consensus - signalling a return to much colder conditions by the end of next week deserves an early mention. More on all this in a moment...

So onto next weeks developments..

The week actually starts with a temporary return to something a tad milder. B y Tuesday, we expect a spell of fairly widespread rain - with hill snow on it's leading edge, tracking eastwards - behind which, temperatures will peak somewhere around the seasonal average. But thereafter, the trend is one for cold anticylonic weather to steadily exert itself across the country and into the second part of the week, a return to something a good deal colder will become apparent pretty much everywhere, with the exception of the far West and NW.

Between Friday and Sunday, developments are expected to yield a bitterly cold easterly flow off the continent, bringing the risk of snowfall - some potentially heavy - into parts of the SE initially, with a chance of this spreading further westwards to affect other areas. And beyond that, the anticyclonic south-easterly flow could well be replaced by a cyclonic east-to-northeasterly version, thereby continuing to offer a growing risk of further snow.

Hes not the only 1 either thats saying the same thing, Im sorry admin if this is the wrong thread but we need that sort of belief in this thread now.

[Duane S.]

i could repeat the post i made yesterday morning and hope i wont get too much grief!! the gist is, until the shortwave energy stops coming into the northern arm, we have a problem. we now have a series of gulf shortwaves (which NOAA alluded to yesterday). the siberian block is headed sw. as iceberg says, without the atlantic stalling, this block will end up to our sw. i have an awful feeling that we could see a west based -NAO (as GP plumped for yesterday)wihtout us having any ride to get there. the way the ukmo looks at T144 with all that energy past the meridian, the trough could easily become elongated and the arctic high could slide sw, way to our north. the siberian block having become a sceuro or even eastern european high. i hope a few will be a litle less dimissive of the options today - the window remains open but by tomorrows 12z runs, we will see if we are able to get the block into a favourable position before it closes.

a glass half empty post, but worryingly, i cant see to find any more water at the moment.

I don't see why you should get grief BA. You are spot on in your concerns, they are mine too. Have we underestimated the Northern arm? because if we have it could well be game over before it stared for sure. These SW's coming out of the states and what they do is going to be critical to the situation for sure.

Edited January 30, 2010 by s4lancia

[BLAST FROM THE PAST]

Fred, can't say I agree that the GFS is any better. The ensembles sum up the shift overnight with more in the way of milder outcomes appearing:

http://www.wzkarten.de/pics/MT8_London_ens.png

http://www.wzkarten.de/pics/MT8_Manchester_ens.png

http://www.wzkarten.de/pics/MT8_Aberdeen_ens.png

Time will of course tell, but I know where my money would be going if I was a betting man.

At this rate, the easterly may arrive in March! :lol:

ENS are as fickle as the models. Monday IMO before the right answer, and pressure to NW/NNW is where we start or should look, not east. Just looked at them, particularly London and they still colder than averge. Not bad at all.

BFTP

Edited January 30, 2010 by BLAST FROM THE PAST

[Great Plum]

Well, it's like the hangover from a big party hosted by the 18z GFS pub run isn't it?

I rarely post on this thread, leaving the discussion to those who have a clue what's going on... however, this is now my 7th year of being on Netweather and I still think this could be all to play for...

For a start, this is no ordinary winter - I have seen synoptics that are a million miles removed from what we have had this winter in previous years - certainly this is a relatively unusual set up we have at the moment.

So which way will it go? I'm not a betting man (unless there's a lot on the euro millions) but I'd have to say this could really go either way! The UKMO is bullish with the west winning out - however, only a week or two back it had that easterly that we were meant to be enjoying last week that disappeared only a day or two before it was meant to happen. The GFS still gets us the easterly and the ECM isn't too bad...

Those who are saying the easterly keeps being pushed back are perhaps being a little unfair... the Easterly has mostly been progged to start around the 8th Feb - it's a day that keeps appearing. Sure, runs like the 18Z last night brought it closer in the timeframe, but this has been only rarely progged...

Lets see what the rest of the weekend's runs have to say, but if the UKMO hasn't changed its mind in the next 3 or 4 runs, then we may have to think that the Easterly is not for us this time round...

[chionomaniac]

ENS are as fickle as the models. Monday IMO before the right answer, and pressure to NW/NNW is where we start or should look, not east.

BFTP

Yes that Arctic high slipping towards Greenland is very much on still this morning for around 10 days time. By that time the lower strat PV has shifted towards Canada taking the energy with it.

[BLAST FROM THE PAST]

The message for today, is don't look for truth in the models !.

ECM isn't that poor, but it's not as good as the 12Z run by a long way, you also have to admit that the GFS ENS isn't as good either as it shows too much scatter with little trend, yesterdays 12Z ECM EPS also shows a lot of scatter. It should be added that both runs do though average/mean out a cold spell of weather.

It's noticable that the GFS and METO bring up a fresh batch of Energy from way off towards Florida, obviously this is a bit akin to adding petrol to a small flame as it hits the colder air coming off the eastern seaboard, hence the models are showing a 940 low, ECM also does this.

There are big differences though in how they handle this extra energy and the timing of the interaction.

The extra energy doesn't need to be a problem, not if it stay out west enough and throws up a ridge, however if al la UKMET it comes into an elongated trough set up, then it goes over the top of the High, almost a critically bad set up.

ECM brings the energy up with a 48 hr delay, slows it down and stalls it out west, which is why is gets their in the end.

GFS deals with it in a much neater why, with a similar timeframe as UKMETO approx 96hrs, it quickly moves up and into main upper low and throws up a ridge stalling it sooner, allowing the Siberian/Scandy high to move over, which in turns opens the door for the Jet to go under the ridge.

GFS spoils it a bit in the longer timeframe by bringing yet more energy in.

This IMO is the paradox of Feb that GP has been talking about. We have two options a strong jet under cutting, which could provide considerable snow, assuming the high to the N has enough strength.

The second option is a strong jet that keeps the cold out of reach.

So I get back to my original statement don't look for truth in the models atm. I think it will take 48 hrs to get some agreement on what to do with the Florida energy and there might well be more issues after that.

A much more uncertain Iceberg...

An excellent post. Many should read this regarding the model watching, and do you know what...I concur :lol:

BFTP

[The Weather Dragon]

Probability in an easterly continues to reduce today - ensembles more scattered in the medium term - UKMO steadfast & Atlantic ready to fire up. Easterly & dream synoptics always have been in FI. Use 144 as a medium term benchmark & look for cross model support at this timeframe

[nick sussex]

i could repeat the post i made yesterday morning and hope i wont get too much grief!! the gist is, until the shortwave energy stops coming into the northern arm, we have a problem. we now have a series of gulf shortwaves (which NOAA alluded to yesterday). the siberian block is headed sw. as iceberg says, without the atlantic stalling, this block will end up to our sw. i have an awful feeling that we could see a west based -NAO (as GP plumped for yesterday)wihtout us having any ride to get there. the way the ukmo looks at T144 with all that energy past the meridian, the trough could easily become elongated and the arctic high could slide sw, way to our north. the siberian block having become a sceuro or even eastern european high. i hope a few will be a litle less dimissive of the options today - the window remains open but by tomorrows 12z runs, we will see if we are able to get the block into a favourable position before it closes.

a glass half empty post, but worryingly, i cant see to find any more water at the moment.

I totally agree with your thoughts here, theres a window of opportunity but this won't remain open for ever, its all about timing here, if you get the block far enough west in the first place then its in a better position to deflect shortwaves away, the UKMO looks to me would eventually elongate the trough and then things will play out as you suggested.

[BLAST FROM THE PAST]

Not much time, but has anyone been able to save the 18z run, it is 'daft' but greta to look at...even Dickens era wouldn't have handled that!!!! Can anyone save it???? Or tell me how.

BFTP

[TEITS]

Gosh what a poor set of runs this morning. Even I confess the models have taken quiet a leap away from the E,ly.

Look at the GEFS mean at +144. Now remember the mean at +168 for the past 3 days has been trending towards an E,ly.

http://91.121.94.83/modeles/gens/run/gens-21-1-144.png?0

This is also reflected on the temps. We still might have some very cold runs but remember the mean once stood at -8C with a tight cluster of -10 members.

http://charts.netweather.tv/ensimages/ens.20100130/00/t850Cambridgeshire.png

This could all change but for the moment I hate to say it but I feel the UKMO is right. For some reason the UKMO has often been a party pooper wrt to E,lys and this looks to be the case this time.

[Lewis]

What i find hard to believe, is the GFS.

How can it show such fantastic blocking even in the shorter to medium range, only for the next morning to just dismiss it out right.

I know it makes you side with it sadly with the UKMO and ECM showing something different (ECM has been for days).

If you look in the short term with regards the potential for the Easterly, it's banging on our door come wednesday/thursday. If we get too tuesday with it still showing that, i think we'll be ok.

I expect the 06z to bring back the Easterly with a real bite. Although from Friday onwards, i don't have a clue.

Edited January 30, 2010 by Storm Force Lewis

[Totoro]

This may not be the right thread but look at this from Ian Fergusson's Blog.

Remember February 2009? The deep snow that brought London and much of the southeast to a spectacular standstill? It's by no means impossible that we'll see similar weather establishing across the same parts of the UK in a week or so.... and possibly more widely, too.

Usually, I restrict my blog to matters of forecast interest within a few days of the here-and-now, but the growing signs - and growing forecast model consensus - signalling a return to much colder conditions by the end of next week deserves an early mention. More on all this in a moment...

So onto next weeks developments..

The week actually starts with a temporary return to something a tad milder. B y Tuesday, we expect a spell of fairly widespread rain - with hill snow on it's leading edge, tracking eastwards - behind which, temperatures will peak somewhere around the seasonal average. But thereafter, the trend is one for cold anticylonic weather to steadily exert itself across the country and into the second part of the week, a return to something a good deal colder will become apparent pretty much everywhere, with the exception of the far West and NW.

Between Friday and Sunday, developments are expected to yield a bitterly cold easterly flow off the continent, bringing the risk of snowfall - some potentially heavy - into parts of the SE initially, with a chance of this spreading further westwards to affect other areas. And beyond that, the anticyclonic south-easterly flow could well be replaced by a cyclonic east-to-northeasterly version, thereby continuing to offer a growing risk of further snow.

Hes not the only 1 either thats saying the same thing, Im sorry admin if this is the wrong thread but we need that sort of belief in this thread now.

Belief? What does that have to do with it? This isn't a religion you know, we can't influence the weather any more than we can influence those imaginary gods that some people think exist.

I'm thinking that Ian Fergusson is wrong, also that many people are clutching at too few straws, the real cold weather is always a week away (ie in FI) on the model output, etc. Sorry, but I don't think it's going to happen. I'd LIKE it to happen, but I think it's more likely that I'll suddenly develop the brainpower of Einstein overnight. :lol:

I'm a realist, I don't operate on flights of fancy and what 'should' happen or what I (or others) want to happen. With the weather, what will be will be.

Enough said.

[Long haul to mild]

The UKMO is bullish with the west winning out - however, only a week or two back it had that easterly that we were meant to be enjoying last week that disappeared only a day or two before it was meant to happen.

A very good point indeed. I remember the UKMO charts from that time too; both T120 and T144 had cold snowy Easterlies across us which did not materialise and did indeed disappear at relatively short notice.

Yes, the UKMO could be onto something but the above example proves why we should not take its current output as a given right now.

The ECM is a slow burner but it does get there in the end with a E/SE'ly. And once again, the 8th / 9th Feb shows up as the date where things could happen.

I won't be dismissing the GFS FI output; it accurately predicted the snowy Easter in 2008 a long way out and stuck to its guns whilst the other models flipped and dithered.

Still plenty of model excitement to come IMO!

Edited January 30, 2010 by Chalk Serpent

[MR EXTREMES]

What i find hard to believe, is the GFS.

How can it show such fantastic blocking even in the shorter to medium range, only for the next morning to just dismiss it out right.

I know it makes you side with it sadly with the UKMO and ECM showing something different (ECM has been for days).

If you look in the short term with regards the potential for the Easterly, it's banging on our door come wednesday/thursday. If we get too tuesday with it still showing that, i think we'll be ok.

I expect the 06z to bring back the Easterly with a real bite. Although from Friday onwards, i don't have a clue.

i agree there has been some wobbles in the models,

id be very skeptical how all this develops,

there has though been run after run for a week or more of some kind of easterly 3days in a row of meto forecast telling us to look east,

this may change today in there updates but if it dont then i will this time be backing the meto.

and from what im reading its all just delayed.

but id like to see it dominate early in febuary but this is not likely most classsic easterlys wait there turn before flooding in.

[BLAST FROM THE PAST]

Belief? What does that have to do with it? This isn't a religion you know, we can't influence the weather any more than we can influence those imaginary gods that some people think exist.

I'm thinking that Ian Fergusson is wrong, also that many people are clutching at too few straws, the real cold weather is always a week away (ie in FI) on the model output, etc. Sorry, but I don't think it's going to happen. I'd LIKE it to happen, but I think it's more likely that I'll suddenly develop the brainpower of Einstein overnight.

I'm a realist, I don't operate on flights of fancy and what 'should' happen or what I (or others) want to happen. With the weather, what will be will be.

Enough said.

Seeing as I F is a professional, one would be wisely considered to pay attention him over say you or many of us on here??? He /believes' what is going to happen using ALL model guidance. Where does your belief come from...UKMO model? :lol:

BFTP

Edited January 30, 2010 by BLAST FROM THE PAST

[The Weather Dragon]

The UKMO 144 hasn't verified at all well this winter - a point to bear in mind - only a couple of weeks ago it was on it's own in suggesting an easterly outbreak.

[Great Plum]

A very good point indeed. I remember the UKMO charts from that time too; both T120 and T144 had cold snowy Easterlies across us which did not materialise and did indeed disappear at relatively short notice.

Yes, the UKMO could be onto something but the above example proves why we should not take its current output as a given right now.

The ECM is a slow burner but it does get there in the end with a E/SE'ly. And once again, the 8th / 9th Feb shows up as the date where things could happen.

I won't be dismissing the GFS FI output; it accurately predicted the snowy Easter in 2007 (?) a long way out and stuck to its guns whilst the other models flipped and dithered.

Still plenty of model excitement to come IMO!

Thanks... this is obviously a complicated synoptic solution as the models continue to flip flop around...

you are right -still a lot of model excitment!

[TEITS]

Here is an unexpected twist, the ECM ensembles.

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

Absolutely miles warmer than the mean.

Maybe the right attitude at the moment is to assume no model is correct. I've been in these situations before where it could go either way.

[Shunter]

Early morning NOAA discussions seem to dislike the 00z ECM run ( too progressive ) and have used yesterdays 12z ECM in their forecast. This relates to US west coast trough and the SFLW exiting over the gulf at day 4-5.

http://www.hpc.ncep.noaa.gov/preepd/preepd.html

[Totoro]

Seeing as I F is a professional, one would be wisely considered to pay attention him over say you or many of us on here??? He /believes' what is going to happen using ALL model guidance. Where does your belief come from...UKMO model? :lol:

BFTP

Evens the pros get it wrong.

My belief is in my 'gut instinct'. Never fails.

[Weather-history]

The UKMO 144 hasn't verified at all well this winter - a point to bear in mind - only a couple of weeks ago it was on it's own in suggesting an easterly outbreak.

What about UKMO 120hr though?

Its not as if, it is semi blocked at 120hr and then the Atlantic crashes through at 144hrs.

http://www.wetterzentrale.de/pics/Rukm1201.gif

The Atlantic is breaking through at 120hrs or more correctly before this and to me that weakens your point. :lol:

Edited January 30, 2010 by Mr_Data

[nick sussex]

The plot thickens this morning with the latest ECM De Bilt ensembles for the Netherlands, bearing in mind that if the UKMO verified much milder conditions would be spreading into that region. The ECM operational run is a mild outlier from next Thursday and at the key time period theres no support for the UKMO raw output at 144hrs.

http://www.weerplaza.nl/15daagseverwachting/default_pluim.asp?r=midden

The caveat here is normally the operationals have a better handle on shortwaves etc so we should bear this in mind. I've compared last nights ensembles with this mornings and theres no change.

In these situations if the model has picked up on upstream changes then we would normally see the ensembles slowly shifting across, if the model has overreacted then we'd expect a better operational run this evening. However regardless of the blocking signal we need to see the models move away from the UKMO this evening, we have to have the UKMO on side by tonight otherwise the route to an easterly will become extremely difficult and may well not happen at all.