Winter Model Output Discussion - 06Z 09/02/13 onwards

[SLEETY]

dramatic??

really

ok I presume you are referring to the 06Z?

No I'm talking about the path of the low pressure bringing the rain/snow event Sunday/Monday.The forecast was for no snow in my region throughout the event yesterday at all,now just 12 hours later,snow is being forecast for SE,so they are hundreds of miles wrong from yesterdays forcast.

Maybe a virus on the computers

[Snowman.]

The low goes under fairly early

This changes everything many here have said wouldn't be surprised if there are a few surprises.

Until the ECM comes out I'm going to dismiss this as a possible outlier as the ECM has been proved to be a much better model at handling these types of situations.

[bluearmy]

No I'm talking about the path of the low pressure bringing the rain/snow event Sunday/Monday.The forecast was for no snow in my region throughout the event yesterday at all,now just 12 hours later,snow is being forecast for SE,so they are hundreds of miles wrong from yesterdays forcast.

Maybe a virus on the computers

no sleety - not hundreds of miles. fifty miles and a change in the shape of the shortwave can have big knock on effects. sometimes i wonder if we bother to read the posts from experienced members who repeat the mantra 'it will be different tomorrow'. these small changes happen all the time with features such as this. generally it doesnt matter what type of rain you receive so you dont notice them. its only when there is a rain/snow boundary that it becomes relevant.

[chris55]

No I'm talking about the path of the low pressure bringing the rain/snow event Sunday/Monday.The forecast was for no snow in my region throughout the event yesterday at all,now just 12 hours later,snow is being forecast for SE,so they are hundreds of miles wrong from yesterdays forcast.

Maybe a virus on the computers

Its a developing Low pressure system, not a fully established low bumping into cold air. The latter is much easier to forecast, this is a developing and dynamic situation, even the best computers will not have the exact track/ppn spread/intensity nailed untill just a few hours before. No virus's, just a very tricky forecast.

Edited February 9, 2013 by chris55

[Ryan Dutch Weatherman]

Wen you look my postings from morning , i had show the CFS 18z , it complete back the GFS 06z.

Also back up from the Cptec .Also some other models as wel.

Ec ensemble dont know after wednesday.

Look here the CFS 18z .

[SLEETY]

Wow

lol means jack.They cant even get the track of the low pressure correct 48HOURS away,so I wouldn't have too much faith in that chart,only saying....

[chris55]

Just to highlight Sundays uncertainty, compare the 00z NAE with the 6z NAE, run 6 hours apart but Sunday evening looking quite different on both

00z, weak band through the Midlands

06z, snowrisk more widespread and further north

[TEITS]

Massive difference in the GEFS control also.

Haven't the time to view all of them so would appreciate someone who can.

[SLEETY]

no sleety - not hundreds of miles. fifty miles and a change in the shape of the shortwave can have big knock on effects. sometimes i wonder if we bother to read the posts from experienced members who repeat the mantra 'it will be different tomorrow'. these small changes happen all the time with features such as this. generally it doesnt matter what type of rain you receive so you dont notice them. its only when there is a rain/snow boundary that it becomes relevant.

Good points.It's just the forecaster was so adamant it would be rain only event for the SE,no mention of any uncertainty or any changes to happen the next day.So what caused the big change,and it was more than 50 miles,snow was only shown for north midlands upwards.

[Cheshire Freeze]

Wow

Get the Greenland high in place and we can experience -10 to -15 uppers well into March. Been waiting for it all winter!

[Ryan Dutch Weatherman]

Heey also CMA ., CFS , CPTEC , seems to me backing up GFS 06z.

I told you before, lot of things will happen ,Unexpected,

Read all my postings from within 12 hours timeframe .

Also march , Cfs 15 runs at row , the daily en also the version 9.Complete madhouse.

This could be something big or a hoax .

[snowking]

I haven't had time yet to go through the individual members yet, but certainly more influence from the east thus far from the ensemble mean:

This is the GFS, and it has been pretty clueless up until now, so we can't just jump on one run because it shows what we like.

What has been encouraging, of course, is the 500mb anomalies showing up around Greenland in the 10-15 day period...

SK

[Mucka]

They probably throw their toys out of the pram when they see the viewing figures for the X-Factor

I can't see why this evolution isn't as viable as the others. I can't see that much energy coming across at us from the US as all the runs showed this morning. Vortex draining out of Canada and yet the atlantic continues on its merry way?? I really don't think it will happen like that. But maybe I've just gone mad

Nope you're sane. Fascinating output this morning and I spy a change in the way the jet is being modelled from the mid term.

People should forget GFS 00z Op and look at the big picture.

UKMO 144 is really a much more interesting chart than it looks at face value, not because it is cold or it promises cold but because it is clear it is looking to develop a new downstream pattern.

Overall we are seeing the second system being forced further West and sliding more and more and behind that we are seeing the Atlantic relax and a more amplified pattern with a new signal for height rises to the NW.

Sometimes we have to look beyond the raw output and look at the trends and if the trend continues through the weekend we could be looking at some surprisingly cold charts next week or even later this weekend within the 10 day range.

I say trend because it can be seen across all models so it is not a blip and it was no so very long ago all the models were sending all the energy from the mid term over the top.

Great output.

Edited February 9, 2013 by Mucka

[weather eater]

Did somebody slip the 06z a couple of stiff brandy’s this morning, certainly this run is out on its own compared with recent runs, yes some GFS runs have modelled heights to rise over Greenland but those were way out in FI, this easterly projection has popped out of nowhere. Of course on its own its just a passing fancy but if it gets any support over the next couple of days then it might start to look more plausible.

[Long haul to mild]

Of all the GFS runs to show a great evolution, it had to be the 06z didn't it!

I do hope this is the start of a new trend but my head says its just the worst verifying GFS run of all having a wibble. However, as Ryan says, it does have some minor model support and NOGAPS (the rapidly becoming ex-cannon fodder model!) has had this setup on one or two of its recent runs too.

Edited February 9, 2013 by Chalk Serpent

[johnholmes]

No I'm talking about the path of the low pressure bringing the rain/snow event Sunday/Monday.The forecast was for no snow in my region throughout the event yesterday at all,now just 12 hours later,snow is being forecast for SE,so they are hundreds of miles wrong from yesterdays forcast.

Maybe a virus on the computers

sleety

Forecasting precipitation is far harder than predicting max and min temps for one thing, even sometimes getting the track of a low correct.

I'll have a look at what the track showed for the low from the 12z yesterday and the 00z this morning, changes do occur at short range and it something anyone has to accept I'm afraid.

The position of the low on the 12z, 00z and 06z is 'roughly' the same although its depth is altered, another thing that occurs as the models fine tune the pattern as T+00 approaches.

Looking at the precipitation outputs and the areas of heavier type have changed. Again you have to accept this, predicting rainfall or snowfall is very difficult to get the right amount in the right place at the right time. Just one of those things that meteorologists are constantly trying to improve and, if they have any hair, often gets them tearing it out!

hope this post helps a little?

[bluearmy]

Massive difference in the GEFS control also.

http://modeles.meteo...s-0-1-138.png?6

Haven't the time to view all of them so would appreciate someone who can.

dave, plenty of support to cut off the disrupting trough (again). thereafter, a varied range of solutions reflecting the options on where to disrupt the next energy and where to drop it into our latitude. given the recent ens and stewarts telecons, the operationals seemed a bit odd over the past day or two. methinks the nwp is sniffing around and trying to work out where to go. (and doesnt have it right yet)

[Frosty.]

Heey also CMA ., CFS , CPTEC , seems to me backing up GFS 06z.

I told you before, lot of things will happen ,Unexpected,

Read all my postings from within 12 hours timeframe .

Also march , Cfs 15 runs at row , the daily en also the version 9.Complete madhouse.

This could be something big or a hoax .

Keep up your excellent posts, full of enthusiasm and knowledge

I think the period from around next wed/thurs onwards is a lot more open to changes and the cold block may have a bigger impact than some recent op runs have shown, game on.

[SomeLikeItHot]

Good points.It's just the forecaster was so adamant it would be rain only event for the SE,no mention of any uncertainty or any changes to happen the next day.So what caused the big change,and it was more than 50 miles,snow was only shown for north midlands upwards.

I think the low centre moving 50 miles is what he is talking about this can change what areas do and don't get snow/rain by much further. Obviously there is much uncertainty, the Met Office has been continually changing the forecast at my location over the last 12 hours from mostly sleet, to mostly heavy snow, to sleet and mostly light snow, and back again.

[Cheshire Freeze]

I think the Dutch weather man is onto something with the charts he had been showing

The CFS has been consistently showing cold late Feb and March for some weeks

Although most recent run is mild.

I must admit I'm perilously close to throwing in the towel. 6z GFS maintains my interest just a while longer.

Edited February 9, 2013 by CreweCold

[Manchester_Sunset]

I think maybe the East will get more accumulations with the heavy showers coming from the Easterly. The forecast is certainly had a change for Yorkshire, higher ground now from 20cm to 10cm with lower levels seeing sleety conditions.

[Frosty.]

Hasn't anybody learnt anything? the 06z output is a huge cold outlier and has been throwing in these 'rogue' runs the last couple of weeks only to completely drop them.

It has to be said the modelling in these blocking situations has been nothing short of pathetic this winter and continues to be so - I really don't know which model at the moment will be more accurate in the short and medium term, lord knows what will happen on Sunday/Monday.

It has support, as our dutch friend has mentioned, and it's the best cold gfs run for ages, if it was even ½ right, I would be happy.

[Yarmy]

The Canadian PV lobe begins its retreat at about T84. That's what I'll be looking for in this evenings' runs.

As for tomorrow...well as Norbert Wiener said "The best model of a cat is a cat" so I'll be looking out my window.

[Barry12]

I think maybe the East will get more accumulations with the heavy showers coming from the Easterly. The forecast is certainly had a change for Yorkshire, higher ground now from 20cm to 10cm with lower levels seeing sleety conditions.

06z GFS brings snow for us.

[phil nw.]

The 06z GFS shows a way where we could bring that cold back west later next week.

It shows the energy attacking at a better angle SE which allows the ridging Azores High to build around the top of the low sinking across the UK thus linking with the Scandi High at a more northerly latitude.

http://modeles.meteo...gfs-0-150.png?6

In this marginal setup it shows just a minor difference on the angle of that sliding low allows the block to the NE to regress west which brings the easterly in.

Of course it`s only one run and we need to see more support but there is a signal for a build of height anomalies towards Greenland the week after next and this is a way that this could happen-ie easterly to a northerly.

http://176.31.229.22...-0-0-204.png?12

It would be a decent finish to Winter if this evolved.