12z model discussion - snow or sleety rain?

[TEITS]

The fax chart is out for thursday and because of the confusion this is our most reliable chart at the moment and i've drawn who would get snow/rain.

[Yeti]

yes it could be yeti! By the way, when people regularly refer to this place going into meltdown, i think this is the beginning of what is meant. A constant stream of posts. Amazing charts just a couple of days away, with incessant posting of newly found incredible snow charts. A couple more runs showing the same stuff, or better, and this place will fully go into meltdown. Its hectic already, but it could get busier

Remember the pappy cold spell recently? The cold spell thread had about 15-20 posts per minute

A quick question - I missed the 6z while at school, can someone give me a summary?

[wellington boot]

The fax chart is out for thursday and because of the confusion this is our most reliable chart at the moment and i've drawn who would get snow/rain.

Hmm useful - im bang on the front line, perhaps a bit north of it!

[suffolkboy_]

Hi everyone

To be honest this event is going to be hanging in the balance until it actually happens. The charts have little experience of this kind of event, so you can't expect them to be spot on at all, and they are unlikely to agree either, right up until the time, it's a guessing game for all of us, including the super computers!

[Matty M]

ECM is out to 72hrs and not too good.. very similar to GFS 12z

[kold weather]

Eye, i think thats probably quite close to what will happen, ahead of that front and there wil llikely be snow, behind it and that snow will turn readily to rain. The big problem is exactly how fast the front will move in and where it will slow down, rarely do the models get it bang on and obviously given the tight gradient there is between snow and rain line that obviously means much uncertainty, though its fair to say the further north the better and the longer it'll last, i think most places have a shot at snow at least at one point between late Tuesday-Sat.

Matty, ECM may not look great but at 72hrs still cold enough for snow over quite a large area of the UK, tohugh it is indee very similar to the GFS, not sure whether too much can actually be read into any models right now, we are at the stage where the models won't matter soon as we can start to nowcast.

Edited February 5, 2007 by kold weather

[MAF]

The fax chart is out for thursday and because of the confusion this is our most reliable chart at the moment and i've drawn who would get snow/rain.

thanks a lot pal!!! you could have made the division line between rain/snow a bit lower down :o

seriously though teits, i reckon you are not far out there

[dapick2002]

Remember the pappy cold spell recently? The cold spell thread had about 15-20 posts per minute

A quick question - I missed the 6z while at school, can someone give me a summary?

followed on from the 00z so still poor

[BristolBlizzard]

The fax chart is out for thursday and because of the confusion this is our most reliable chart at the moment and i've drawn who would get snow/rain.

*Cries*

[wintermaster]

They seemed pretty confident that heavy snow is on the way, so cheer up...

I think they dont have a clue. Just seen the forecast at 6.30 and they only went upto wednesday night. They said alot more snow is possible on Thursday but no real forecast.

[Nick F]

ECM is out to 72hrs and not too good.. very similar to GFS 12z

UKMO seems on it's on with the first low during Wednesday, ECM also takes it further South into N'ern France:

I don't think the T+72 is too bad for those North of the M4 with sub -4C 850mb temps it's marginal but with low heights snow is very much possible for the Midlands, North of the Midlands less margainal with colder sub -6C 850s, but the precipitation may not get that far North, hard to tell without ppn charts from ECM.

[Matty M]

UKMO seems on it's on with the first low during Wednesday, ECM also takes it further South into N'ern France:

I don't think the T+72 is too bad for those North of the M4 with sub -4C 850mb temps it's marginal but with low heights snow is very much possible for the Midlands, North of the Midlands less margainal with colder sub -^C 850s, but the precipitation may not get that far North, hard to tell without ppn charts from ECM.

Yes its very touch and go certainly not a bad run by any means..

You would need to consider, dewpoints, 2m temps ! But unfrotunately we dont have them charts..

Out to 96hrs now and again similar to 12z GFS

Risk very high for Northern Ireland but 60miles here or there will mean i can get rain or snow !!

[johnholmes]

blog No 9 is on its way in few secs, its a big file, so only out to Thursday morning, Ill try and do another 24 hours later after some dinner.

[swfc]

Well both our local weather on calendar and the bbc are saying its on a knife edge.Fax charts look pretty good and thats the charts they were using up to sat.

[mcweather]

Having lived through a good number of these situations un the 70,s and 80's the major problem with the forecasts was the the northward extent of the fronts moving up from the south or south west. It was almost invariably over played and as Steve M inferred last night don't be surprised to see the projected snow zone somewhat further south than is being progged even on the fax.

These sliding lows have a habit to track further south than forecast rather than further north. Believe me I've been there.

[kold weather]

Also worth remembering that the set-up is fluid so while the T72hrs may not look good for snow for some people, say at T69hrs it may look a whole lot better. This set-up is the type that the warm air will try and displace a weak but quite stubborn mass of colder air to our north and so at least at first the warm air may well just go over the top of the cold airmass and will take some time to mix, couple that with as nick said low thickness and i think there is highly likely to be a good 2-3hrs of snow even in the south before it turns back to rain. The big problem with this set-up is that its so tight that if the modelshave the front going to slow/too fast it'll severely impact our chance sof snow for much of the country for either the positive or negative and thats why its such a hard call to make even for the models considering our place in the global scale is small.

mcweather, yeah the models tend to under-do the supression of these lows because they slightly over-cook the system and under-do secondary depressions which would do us a large favor as the UKMO run shows. I'm not sure whether this wil lbe the case this time but sometimes these fronts can have a harder time then expected and don't be suprised if the first front actually fizzels out until more forcing comes in rom the Atlantic as the main feature starts to head eastwards.

Edited February 5, 2007 by kold weather

[The Eagle]

ECM is good for the north generally for a time but milder does win out far sooner then the UKMO. Both looking quite different. So backto square one really I suppose. We are no wiser then we were yesterday.

[MAF]

blog No 9 is on its way in few secs, its a big file, so only out to Thursday morning, Ill try and do another 24 hours later after some dinner.

thanks John, makes good reading. enjoy your dinner!. :blink:

[guitarnutter]

Please stop with these silly comments. They come across as very childish. I dont mean to come across as a grumpy old sod but it is spoiling my reading of 'some' interesting comments'. Reading the charts has always been an 'up and down' experience and there is no point in complaining about a chart because you dislike it. The reason you are complaining yourself is because you've been following the charts and they currently are not showing what you or most of us actualy want. Damn i hate moaning so sorry about that.... carry on!

sorry its just that i wished that the charts were not so inaccurate. if only they were only released T-60hours to avoid disappointment all around.

[Yeti]

Freezing rain perhaps possible if the warmer air mass slides above the cold? Maybe an outside chance.

I seriously hope the lows haven't been progged too far N - although surely forecasting systems have moved on a lot since the 80's?

[pinball wizard]

Back the form horse or the model thats showed the most consistency which has been the ukmo over the last few days, the reason for so much trauma in here is the over reliance on the gfs which throws up four runs a day and sends people hurtling towards the prozac cabinet far too often.

This is a common gripe of mine that this model thread ends up being the gfs discussion thread and the other models are often cast aside. The gfs is not fallible as we've all seen over the last few days, anyway lets hope the ecm keeps the upbeat mood going.

Couldn't have put it better myself :blink:

[Snow Queen one]

Just looked at the net weather extra charts and they say the south including SE will get rain as min temps are around 4 and ground temps are well up. We in the south may have to miss this one out. There's always next year. :blink:

[kold weather]

Its still a hard call tohugh Yeti, and the uncertainty is clear to see given how much the UKMO differs to the GFS at even 36hrs, there is over 100 miles differenc ein the wave's center that is progged to clip the south on the UKMO run, thats quite siezable given its quite close now. There is a chance the models are a touch to ofar south or they may be too far north as a couple have stated, these things are awfully hard to prog until they arrive, hence why the beeb only dare go up to Wednesday and not even mentioning anything other then the chance of snow on Thursday.

Freezing rain is a possiblity and to be fair there could be nearly every type of wintry precip possible as that front pushes up, its going to make for a very hard forecasting set-up, but its got a real shot at given some very heavy snowfall for quite a prolonged time in the north, with nearly everywhere possibly seeing ome snow bar maybe the far far south.

Edited February 5, 2007 by kold weather

[Teesdale]

http://www.meteociel.fr/modeles/ecmwf/run/ECM1-168.GIF?05-0

Scotland looking good

Mark

Teesdale,Co Durham

Edited February 5, 2007 by Teesdale

[shuggee]

Can we stick to discussing the models in this the appropriately titled 'Model discussion' please.

If you want to talk about what's being said on the telly or on the internet or even in Razzle please go over to the Media Section and post in this thread:

http://www.netweather.tv/forum/index.php?showtopic=36077

Thank you :blink: