Model Output General Discussion

[MKN]

Another fantastic run, keeping the cold going on and on in the more reliable timeframe, not the snowiest of runs from my point of view, but detail about that is to early to comment on, the main thing is it look certain to stay cold for quite some time.

[Tom D]

This run pushes the troublesome Atlantic low over France and over further east in Europe, leaving cold air over the UK, with precipitation, until next Wednesday!

There's also the possibility of more cold being pushed over the UK after +180, but FI takes the mild alternative.

[Harsh Climate]

Great looking charts again this morning! And if anything have moved somewhat away from a quick breakdown.

I think the reason why is the new developements of low pressure just off portugal..

http://www.wetterzentrale.de/pics/Rtavn1321.png

http://www.wetterzentrale.de/pics/Rtavn1561.png

With low pressure south far south, moveing east they allow for the Jet stream to head further south and keeps us in the cold artic air, while the milder air is just too far south to affect us. And been on the northern side of this airmass, any precipitation thrown up is likely to be snow.

Getting really excited now, never have I seen such a window of opportunity for the uk to recieve heavy snow. Theres likely to be snow showers (thu/fri), frontal snow moving south saturday night and battle ground situations further on. Appologies to anyone I annoyed yesterday, shouldnt have hammered home my points so hard

Edited December 16, 2009 by Jed Bickerdike

[Stu_London]

06z brings the breakdown around Xmas day, although even those charts would appear to have potential for a second shot soemwhere down the line.

[Potent Gust]

Another great run for cold lovers. Could be a few ice days coming up if these charts verify. The mild breakdown looks to come in around Christmas Day but lots could happen in the meantime and even then it does not look that mild

[Yeti]

Now if that isn't a snow dome over Bonn I don't know what it is!!

http://www.wetterzentrale.de/pics/Rmgfs72sum.gif

So disappointing really that despite absolutely bitter temps here, everything is so dry.

It's encouraging to see the ECM want to maintain heights to our N - the GFS has hinted at this at times as well. That would make it a lot harder for the col air to budge and would delay any breakdown until after Christmas.

Meanwhile, the UK looks like getting pasted starting Thursday night - so enjoy and let's hope some people see some really deep snow this weekend.

[mountain shadow]

Typically as we move past T+180 it breaks down from the south. This 6z is a massive

upgrade on yesterdays 6Z

We are already into at least a 10 day cold and snowy spell IMO with the signs of a renewed surge of cold air betweej christmas and new year.

Given that most forecasters went for a average/mild December and a cold January, the signs are their for a memorable winter.

A New even larger teapot perhaps.

[kold weather]

Yep a breakdown occurs on xmas day on this run, though temps stil ldon't look that mild it has to be said after that, also note the flip to a milder flow once again occurs just after 180hrs as the resolution drops away, so thats once again an interesting thing to note.

Anyway the 06z is a pretty impressive run once again upto the breakdown, would take that quite happily.

[snowmadchrisuk]

Typically as we move past T+180 it breaks down from the south. This 6z is a massive

upgrade on yesterdays 6Z

We are already into at least a 10 day cold and snowy spell IMO with the signs of a renewed surge of cold air betweej christmas and new year.

Given that most forecasters went for a average/mild December and a cold January, the signs are their for a memorable winter.

A New even larger teapot perhaps.

Yes the Models and the Ensembles over the last 48 hours have pushed the breakdown from the 23rd to the 25th .. If were lucky we may even get a few extra days as the week goes on .

Edited December 16, 2009 by snowmadchrisuk

[Jan 87]

Not such a good FI and shows how it could go wrong if the jet doesnt quite play ball, but the trend is still ok and a few hundred miles either way will make a huge difference. At the moment I would say a breakdown around Xmas day but if the low stalls and pushes east, then we could even see snow in the south

[Joneseye]

Do any of the forecasters on here buy the evolution after this weekend on the 06Z GFS? When I say this I mean the way the low pressure and mild weather progresses it's way into mainland Europe so easily?

[Cloud 10]

A tad chilly over the country for the middle of next week,-10 max over northern scotland. maybe some december temperature records being broken over the coming week or so.

[Harsh Climate]

Do any of the forecasters on here buy the evolution after this weekend on the 06Z GFS? When I say this I mean the way the low pressure and mild weather progresses it's way into mainland Europe so easily?

Well I think its quite likely. Its all to do with the greenland block edging further north west, this then allows atlantic lows (from the eastern seaboard of america) to spin in to the vacated area and head east into europe.

http://www.wetterzentrale.de/pics/Rtavn1081.png

As the low heads in it opens the door for the jet to power through with mild maritime air rapped around the lows heaing into europe. The good thing for us though is latest developements are suggesting the invading lows might be just too far south to affect us and we remain in the cold artic airmass with the jet further south.

Edited December 16, 2009 by Jed Bickerdike

[kold weather]

Do any of the forecasters on here buy the evolution after this weekend on the 06Z GFS? When I say this I mean the way the low pressure and mild weather progresses it's way into mainland Europe so easily?

Well I personally think it won't be quite as straight forward as the GFS would has us believe but thats probably because of the resolution, I'd put any money on a shortwave trying to introduce milder air ahead of the main low if the 06z was relaly right...however there are any number of solutions possible after 144hrs.

For now I think the 06z GFS looks much more realisitic with the low pressure system and its strength, the run is a good deal closer to the eCM/UKMO at 144hrs then it was on its 0z run. I personally like the 06z run far better as the 0z GFS would have introduced milder air in the SE by 168hrs...this run keeps it cold enough right upto xmas morning.

[Frosty.]

Just another variation from the 6z, no more likely than what the 00z gfs showed and a definate upgrade on what the 6z showed yesterday. The possible mild breakdown is being shunted back bit by bit and the latest run only really turns it less cold with a threat of colder weather returning. Another feature of this run is how unsettled it remains all the way through so if there is a change to less cold, there would be a serious flooding risk with all the rainy weather and the snow melt which would be considerable. Scotland still has the best chance of remaining cold enough for snow on hills even in deep FI.

[stewfox]

I don't know why no one in the model discussion group has not picked up on the heavy snow in Reading which is now settling everywhere.

Rain/sleet forecast 3/4c

Has the cold air hang around for longer?

Whats going on re T24 ?

Edited December 16, 2009 by stewfox

[Coast]

I don't know why no one in the model discussion group has not picked up on the heavy snow in Reading which is now settling everywhere.

Maybe they are discussing it over here? netweather.tv/south-central-england-cold-spell-discussion

[MP-R]

I don't know why no one in the model discussion group has not picked up on the heavy snow in Reading which is now settling everywhere.

Rain/sleet forecast 3/4c

Has the cold air hang around for longer?

Whats going on re T24 ?

Yes, the radar confirms that small area of precipitation at Reading at the moment:

http://www.raintoday.co.uk/

Back to the models however, looks like some sort of breakdown around Christmas Day though I suppose there is plenty of time for the low to stay to the south of move northeastwards and bring back down cold air soon after. Equally, what would be the chances of freezing rain Christmas Eve/Christmas Day even if snow doesn't fall, isn't that what happened under a similar setup at the end of December 1995?

http://www.wetterzentrale.de/pics/Rtavn2161.html

A bitterly cold night showing for Tuesday too

http://www.wzkarten2.de/pics/Rtavn14417.png

[stewfox]

Yes, the radar confirms that small area of precipitation at Reading at the moment:

http://www.raintoday.co.uk/

Back to the models however, looks like some sort of breakdown around Christmas Day though I suppose there is plenty of time for the low to stay to the south of move northeastwards and bring back down cold air soon after. Equally, what would be the chances of freezing rain Christmas Eve/Christmas Day even if snow doesn't fall, isn't that what happened under a similar setup at the end of December 1995?

This makes me laugh

Heavy snow is Reading is totally relevant to the model discussion as its clear something within T24 has not happened as 'forcast'. Rain/sleet this afternoon 3/4c was the model forcast. Its -1c heavy snow

Ill let people keep talking about T144, which seems to be the default or talk about 1995.

If anyone wants to discuss the change in the model out put I would be happy to hear. I assume the cold has not gone away.

[MP-R]

This makes me laugh

Heavy snow is Reading is totally relevant to the model discussion as its clear something within T24 has not happened as 'forcast'. Rain/sleet this afternoon 3/4c was the model forcast. Its -1c heavy snow

Ill let people keep talking about T144, which seems to be the default or talk about 1995.

If anyone wants to discuss the change in the model out put I would be happy to hear. I assume the cold has not gone away.

Fine, what you say is true but I've always been under the impression the model output discussion is about what is to come by what the models show, not what is happening currently or what has already happened. There are plenty of threads such as Snow Reports or the South Central Cold Spell Discussion for that.

Besides, I did not mean that post in a 'you're going off topic' way, I simply meant I was now going on to talk about the models themselves as opposed to the weather conditions. Perhaps that was misleadingly worded on my part, my bad.

[Bottesford]

And back on topic again please!!

[MKN]

Could someone with more experience try to explain why the latest bbc forecats only show snow in the east and south east when currently the fax charts look to have alot of potential for snow stretching right across from east anglia to wales??

http://www.wzkarten.de/pics/brack0a.gif

http://www.wzkarten.de/pics/brack1.gif

http://www.wzkarten.de/pics/brack2a.gif

[memories of 63]

I like the GFS Control today. It shows a small area of HP pushing the LP S allowing another pulse of cold air to drop over the UK around 29 - 31st

[Eugene]

First look at the ensembles today and its looks to me like more members prolong the cold spell to around the 27th of December, exceptional runs today its going to feel bitter thats for sure, it already does today in the south midlands and south.

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

[aspire27]

A tad chilly over the country for the middle of next week,-10 max over northern scotland. maybe some december temperature records being broken over the coming week or so.

A newbie here, the above chart showing 2m temps..not very cold for the south 3-7 on that chart.