Model Output Discussion

[yamkin]

GFS is looking more like the ECM at 144 with the atlantic undercutting...

Perhaps a big snow event for some.

It's really the other way round. GFS started the Easterly a few days ago and the ECM was not having it. ECM now wants the Easterly

[Bobby]

Remember that the UKMO we see is just one operational run. The UKMO has ensembles too that we don't see so it could be mild outlier.

[yamkin]

I'm very surprised the UKMO have gone with their own model with tonights fax charts especially as theres no support in the ECM ensembles, their 144hrs output would bring milder air into the Netherlands which has absolutely no support in the ECM De Bilt ensembles suite so its bizarre that they've gone with their model earlier on.

The GFS 18hrs run is almost a carbon copy of the ECM, this indicates to me that the ECM signal for its output in the crucial time frame upto 144hrs is strong and the UKMO is on the wrong track here.

Paul Hudson, Ian Fergusson etc are looking at the potential Easterly next week, so it looks like the UKMO is having issues at the moment.

[nick sussex]

Remember that the UKMO we see is just one operational run. The UKMO has ensembles too that we don't see so it could be mild outlier.

The UKMO don't have their own medium term ensembles, they take their guidance from the ECM ensembles.

[Tom D]

GFS control run doesn't get to the easterly so quickly but does by.. yep, 8th February.

I have a feeling, if the other ensembles and models also agree, that it could end up being the 7th/8th when the easterly properly starts kicking in. The control is by no means mild, with daytime temps around freezing by the 4th, just without the easterly wind.

I think the control is about the show a belter in FI as well!

[DEYS(Kent)]

Mean at T240

http://91.121.94.83/modeles/gens/run/gens-21-1-240.png?18

[I remember Atlantic 252]

GFS control run doesn't get to the easterly so quickly but does by.. yep, 8th February.

I have a feeling, if the other ensembles and models also agree, that it could end up being the 7th/8th when the easterly properly starts kicking in. The control is by no means mild, with daytime temps around freezing by the 4th, just without the easterly wind.

I think the control is about the show a belter in FI as well!

yeah was looking at ensembles, most look good but number 5 looks very unfriendly

[cooling climate]

I would like to ask why is it so implausible to see a run like the operational GFS 18z verify.

Everything is there for it to occur ie high coming out of Siberia dragging all that frigid air

with it, the size depth and intensity of the high, all the cold pooling over Europe that will

sustain the bitter air from Siberia, also widespread frost, ice and snow over Europe to

sustain the frigid air.

All that is needed is the right orientation of the high and the rest is history, so to say

definitely will not happen is misplaced I think.

One thing I do remember from past freezes that got to the levels of cold shown tonight

is how ineffective the rock salt is at these bitter temperatures.

Feb 91 for example it was only when daytime temperatures recovered to about -1c that

the salt started to melt the snow where it had been previously laid.

[Guest North Sea Snow Convection]

Its not unusual for the fax chart to be shared between the ECM and UKMO. How often does it change from one model to the other in this timeframe at T120 anyway?

It needn't mean too much *she says theraputically*

Seriously though, the ECM ensembles are the clue. The operational 12z ECM should be pretty well supported and the METO will probably re draw the fax again tomorrow to show the start of the easterly

Edited January 29, 2010 by North Sea Snow Convection

[DEYS(Kent)]

ENS up to T180

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

London

[Tom D]

yeah was looking at ensembles, most look good but number 5 looks very unfriendly

It looks a bit befuddled to me that one.

The mean is great again but still annoyingly past 192 so people will say 'it's in FI there's time for change' etc.

But it's been showing this easterly trend for days now, and I think either tomorrow or Sunday it will start moving before +156...

[LomondSnowstorm]

Literally better than anything I've ever seen on the models ever. Better than if I'd made it myself! I know the chances of it verifying exactly like this are very low BUT almost every run has shown a cold to very cold easterly spell. We can dismiss them all we like but they are looking increasingly plausible given the background signals. -10 to -15 uppers widely across the UK is beginning to trend to almost the favoured option for around the 10th February. If there is cross model agreement for the GFS scenario at +144 hours tomorrow morning, perhaps it's time for optimism, not that that would mean we're home and dry for a potent easterly, but that some form of southeasterly/easterly flow is almost certain for the weekend onwards.

LS

[Altostratus]

Hello,

I know nothing about all the intracies of these runs but similar outcomes to what many folk are posting have appeared on several occasions in the last few days so I suppose it's plausible the big beast could be coming.

I must admit I used the GFS thickness runs, 500/1000's etc. for trend spotting in the last cold spell and they seemed accurate enough and eventually were bang on.

What do GP,TEITS,Nick F etc. think is a sensible timeframe from which to get excited at this rate, T96 maybe? also what's your models/charts of choice to best indicate what to expect at the surface, come the reliable timeframe.

Loving the thrill of the chase of East meets West either way

Cheers

STORMBOY

It’s an interesting time to be model watching isn’t it. We’ve certainly been spoiled this winter. Today’s outputs have shown growing support for a cold spell, but given the evolution to cold occurs well out in FI, confidence still remains low. It’s not worth getting excited just yet. In these situations I tend to use T+96 as safe marker. In normal circumstances I’d be pretty confident up to T+120 but as we all know, these are abnormal circumstances. For the reliable time frame, the GFS serves as useful guide, however the MOGREPS NAE is meant to be better for short range forecasts.

Edited January 29, 2010 by Altostratus

[gottolovethisweather]

I would like to ask why is it so implausible to see a run like the operational GFS 18z verify.

Everything is there for it to occur ie high coming out of Siberia dragging all that frigid air

with it, the size depth and intensity of the high, all the cold pooling over Europe that will

sustain the bitter air from Siberia, also widespread frost, ice and snow over Europe to

sustain the frigid air.

All that is needed is the right orientation of the high and the rest is history, so to say

definitely will not happen is misplaced I think.

One thing I do remember from past freezes that got to the levels of cold shown tonight

is how ineffective the rock salt is at these bitter temperatures.

Feb 91 for example it was only when daytime temperatures recovered to about -1c that

the salt started to melt the snow where it had been previously laid.

Spot on I reckon. The salting of roads could be the least of our problems once again, especially if the over-populated south gets hit again. Some impressive theories in here and only time will tell I suppose. I must admit some folk have an uncanny knack of being bang right on the timing when it comes to our understanding of climate's intracies (?) however. NAO/AO's, QBO's MMW's all go over my head but RESPECT is due to the good folk such as you who are rarely wrong and when you/they are, more importantly, you EXPLAIN why it did not hit the target. Alternatively you could read the Daily Mail, who are never wrong, so I wonder how long before the headline 'SIBERIAN BLAST approaching' appears

Wintry Cheers

STORMBOY

[bluearmy]

i make it that 6 of the ens runs have colder uppers than the op at some point in fi

[DEYS(Kent)]

Full ENS - London

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

[LomondSnowstorm]

I would like to ask why is it so implausible to see a run like the operational GFS 18z verify.

Everything is there for it to occur ie high coming out of Siberia dragging all that frigid air

with it, the size depth and intensity of the high, all the cold pooling over Europe that will

sustain the bitter air from Siberia, also widespread frost, ice and snow over Europe to

sustain the frigid air.

All that is needed is the right orientation of the high and the rest is history, so to say

definitely will not happen is misplaced I think.

One thing I do remember from past freezes that got to the levels of cold shown tonight

is how ineffective the rock salt is at these bitter temperatures.

Feb 91 for example it was only when daytime temperatures recovered to about -1c that

the salt started to melt the snow where it had been previously laid.

Agree absolutely with this post. We can't dismiss an outlook just because it looks a bit 'extreme': sometimes extreme uppers like that do occur. Other runs have been hinting at this as well, and with the cold pool as cold as it is to our east scenarios like this should not be taken off the table. Put it this way: if a less cold southerly was shown at +240 hours would people totally dismiss it as well? In reality the 18Z in general looks just as likely as that, perhaps slightly moreso actually.

Not saying it will happen just suggesting that 'it's never going to happen' comments are slightly too dismissive of at least the general pattern shown by the 18Z.

LS

[gottolovethisweather]

In normal circumstances I’d be pretty confident up to T+120 but as we all know, these are abnormal circumstances. For the reliable time frame, the GFS serves as useful guide, however the MOGREPS NAE is meant to be better for short range forecasts.

Yes indeed I'm loving this very special winter, IMBY last 10c+ max was back on the 9th December, amazing for modern winters!

Anyways, what's 'MOGREPS NAE' and is it free to view on NW.

Cheers

STORMBOY

[Bobby]

Anyways, what's 'MOGREPS NAE' and is it free to view on NW.

Cheers

STORMBOY

The NAE is a high resolution short range model for the UK run by the Met Office (I believe). You can see it here:

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=nae&MODELLTYP=1&VAR=pslv&HH=0&BASE=-&WMO=&ZOOM=0

[West Sussex Kate]

the bbc long range forcast does dismiss anymore large snowfall amounts for the monthly outlook.

however the met office long range forcast does mention snowfall - but doesnt say amounts

[peterf]

the bbc long range forcast does dismiss anymore large snowfall amounts for the monthly outlook.

however the met office long range forcast does mention snowfall - but doesnt say amounts

thats that tidied up then lol.

[Altostratus]

Yes indeed I'm loving this very special winter, IMBY last 10c+ max was back on the 9th December, amazing for modern winters!

Anyways, what's 'MOGREPS NAE' and is it free to view on NW.

Cheers

STORMBOY

It's a high resolution model used by the UKMet. You can view it here:

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=nae&MODELLTYP=1&VAR=prec&HH=0&BASE=-&WMO=&ZOOM=0

I think you can get better charts than that but can't remember where from. If anyone knows of this please post the link so that people can bookmark it.

Edit: Barb beat me to it.

Edited January 29, 2010 by Altostratus

[gottolovethisweather]

The NAE is a high resolution short range model for the UK run by the Met Office (I believe). You can see it here:

http://www.weatheron...E=-&WMO=&ZOOM=0

Thankyou Barb and Mr AltoStratus

Edited January 29, 2010 by STORMBOY

[Bobby]

I think you can get better charts than that but can't remember where from. If anyone knows of this please post the link so that people can bookmark it.

There's the NMM which is even higher resolution, you can see this here:

http://www.meteociel.com/modeles/wrfnmm.php

Only bottom half of Britain though.

Edited January 29, 2010 by Barb-

[Tom D]

There's the NMM which is even higher resolution, you can see this here:

http://www.meteociel.com/modeles/wrfnmm.php

Only bottom half of Britain though.

That's not the best, you can hardly make out the UK borders!

You can pay and view a UK NMM from netweather extra if you're really interested in viewing those charts. I think they're part of the lite sub?

Amazing ensembles once again, fewer mild runs, more cold ones! The average temp mean for London struggles to get above freezing for nearly a week!