Model Output Discussion - Tuesday 20:25 -->

[ribster]

This looks rather good to my untrained eye?

[yamkin]

GFS 18Z is looking good so far

[NorthNorfolkWeather]

QBO, MJO and other tropical-convection wave-related cycles and feedbacks have much more to do with these events than solar minima. I'd suspect the lag-time for solar minima-influenced flow patterns would also be longer.

Hi PP,

I think that the lag is already about 5 years since we had any great number of sunspots and the Solar Wind has been dropping throughout that time. So this could be the 'start' of the effects of the lag

[Geordiesnow]

The ridging doesn't matter remember, if you want a cold plunge you *must* have the shortwave diving down south rather then getting delayed, at the moment this is still closer to the 12z run then the 06z run.

However the easterly is being steadily upgraded for the weekend as well, could be a cheeky one...I suspect whats happening is the intial ridging is actually too strong and shunts the shortwave too far north, so whilst we get a slightly colder easterly flow, the easterly flow further out lacks any real kick to it.

Looks like to me that this run could look more like the UKMO 12Z run than the GFS 12Z with the lower heights in the South becoming more into play.

Not sure what this run will do in truthness which is why i was not that full of joy about the 12Z UKMO run.

Must also be noted that the UKMO also has a shortwave in a similer position to the GFS however it's not as strong.

[clark3r]

The high over britain is further north, that has to be a good thing

does any one know what sort of max and min temps we may nxt week? because the 10 forecast still says it wont even get down to freezing at nigh in the south at the moment! dont know if that is wrong?

[snowmadchrisuk]

This looks rather good to my untrained eye?

If 18z is correct I wouldn't rule out Snow showers for the SE on Sunday. they have cold enough uppers and the 528 dam line right over them .

[Harsh Climate]

This looks rather good to my untrained eye?

There would probably be light snow flurries in the south from that chart.

[Cloud 10]

+132hrs on the 18z,high on its way to greenland,formidable cold pool to the northeast...

[Dingwantssnow]

Am i right in saying that we want the uk high to start heading to greenland??? Because by T+132 thats exactly whats its doing

[Optimus Prime]

Its a better run and more comparable to the UKMO/ECM. Would be nice to see that low dive southward bringing that intense cold around the high.

Edited December 8, 2009 by Optimus Prime

[snowmadchrisuk]

There would probably be light snow flurries in the south from that chart.

424 users ... have we broke a record .... Shame I don't live in the SE , but much better than the 12z output we have to agree .

[kold weather]

Ah don't worry about the 12z UKMO, that would have certainly given the goods...

As for the 18z, the GFS really is upgrading the easterly, its one of those sneak under the radar type situation that takes people by surprise as they are too focused on the big prize so to speak.

We really need the shortwave to expand westwards, if it does then game on, if not then better get used to a cool/cold anticylconic NE, with likely a lot of gloom!

[nick sussex]

Looks like the gfs wants to continue with this trend which although some members might think is taking the long route to much colder is a very interesting run, just following the meteociel charts you can clearly see the whole pattern edging westwards, this is very rare, personally i prefer this pattern as IMO less can go wrong than the ecm. You've got a favourable aligned atlantic trough, energy going into the southern arm of the jet, really very good.

[Harsh Climate]

does any one know what sort of max and min temps we may nxt week? because the 10 forecast still says it wont even get down to freezing at nigh in the south at the moment! dont know if that is wrong?

It all depends on whether its cloudy or not at night time. If its cloudy expect temps of around 2-3 degrees, if theres no cloud expect temps of around minus 2-3.

[NorthNorfolkWeather]

Bingo, with that reasonably slow flow, and those uppers, may get something overnight on Sunday

[snowmadchrisuk]

Has anybody got any Helium to put into our lovely yellow balloon ?

[Duane S.]

Looks like the gfs wants to continue with this trend which although some members might think is taking the long route to much colder is a very interesting run, just following the meteociel charts you can clearly see the whole pattern edging westwards, this is very rare, personally i prefer this pattern as IMO less can go wrong than the ecm. You've got a favourable aligned atlantic trough, energy going into the southern arm of the jet, really very good.

My thoughts as well Nick. A lot safer route to cold this one. I'd still take the ECM I was was offered it today though!

[kold weather]

Looks like the gfs wants to continue with this trend which although some members might think is taking the long route to much colder is a very interesting run, just following the meteociel charts you can clearly see the whole pattern edging westwards, this is very rare, personally i prefer this pattern as IMO less can go wrong than the ecm. You've got a favourable aligned atlantic trough, energy going into the southern arm of the jet, really very good.

Yoe I'm going to disagree here, there is far more that can go wrong with that set-up, for example any shortwave could develop behind the one and because its been too slow in moving southwards, we get stuck with cold air locked to our west and we end up in glorified anti-cyclonic gloom...so when we do get an attack form the SW it'll just be rain...we got very lucky in that respect on the 12z GFS because the low was sooo potent it allowed the surface high to develop well ahead of the actual system.

Saying that, we could still get some pretty potent low level cold in that set-up regardless.

Edited December 8, 2009 by kold weather

[cooling climate]

The ECM extended ensembles look excellent, even the mean runs below 0c for a week.

[NorthNorfolkWeather]

does any one know what sort of max and min temps we may nxt week? because the 10 forecast still says it wont even get down to freezing at nigh in the south at the moment! dont know if that is wrong?

Depends where you are and your profile doesn't say.

Down in Southern England, it wil feel chiily due to the wind, but I'd expect daytime temps to be around 4C Nights will depend on cloud cover -- no cloud and it will be cold, but not as cold if there was no wind.

Mods, should this be moved to the Cold Spell thread?

[Neilsouth]

Don't see this happening , that's a really odd looking high... and another high blocking off the atlantic towards the states lol

[Thundery wintry showers]

I agree with Kold Weather, I think the UKMO/ECM is actually more robust than the GFS. Another issue with a longer-delayed wintry spell is that more shortwave-related issues could potentially crop up before it gets into the reliable timeframe. However I think the GFS 18Z looks pretty implausible as well, so for now I think the UKMO/ECM are the more likely to be nearest to the mark.

Indeed the 18Z sets us up for what looks like a prolonged spell of dry cloudy and moderately cold weather.

Edited December 8, 2009 by Thundery wintry showers

[Neilsouth]

Look at that souhtern jet ! , any further south and we wont see it lol

http://www.wzkarten.de/pics/Rtavn16815.png

[Geordiesnow]

Whilst the upper air temps are nothing special this run does have quite a bit of potential and its quite unusual too see a high pressure looking like it is on this run in the higher resolution of the run.

I would prefer the ecm though, much more interesting in terms of cold and at least it will be bright and not dull and cloudy with rain on the east coast.

[Barb]

Bit dissapointing, this would just bring drizzle and murk - the uppers just aren't really cold enough as the cold easterly supply gets somewhat cut off.