Winter Model Discussion - Cold Hunting -12Z 30/12/12

[Zenarcher]

One question I was going to ask earlier but forgot, I understand the control run is started from a slightly different point to the op? But using the same data as the op? Is this correct?

And is there a reason that in recent days the control run has been consistently dishing out good runs compared to the op that has been quite the opposite? (6z aside)

Their used to be a good guide in the learners area about the control run and how it works but can't find it so from what I can remember it does use the same data but because the GFS gets a lot of new data fed into it each run none of the data can be considered accurate so the control run changes the data and runs it negative and positive to try and limit the mistakes.

Edited January 3, 2013 by weathermaster

[TEITS]

The weather Outlook, in their update today, does not share the optomism of some who are posting on this discussion forum:

http://www.theweatheroutlook.com/

I would tend to agree.

I find it absolutely baffling that anyone can say the coldest weather will miss the UK. If blocking does develop then synoptically the slightest change in the positioning and orientation of the blocking can have massive differences in what direction the cold airmass takes across Europe. Could be S of the UK into France or Turkey, Greece or even the UK.

I would currently rate the chances of the UK getting hit by a cold E,ly around 40% at the moment from now into the final week of Jan. Now yesterday I would of rated this around 10/20% but we have seen an improving trend today. I still wouldn't be surprised to see the +168/+192 timeframe to be upgraded which is why im looking forward to the 12Zs especially the ECM.

Personally I would of expected alot better from Brian Gaze because dare I say it, thats quiet an amateur interpretation of the current model output!

[nick sussex]

Glad to see the UKMO took on board my comments from earlier! lol

I think thats a perfectly acceptable update from the UKMO mentioning the uncertainty and probably wise given that these SSW's are really very difficult to predict in terms of initial response.

[Coast]

Their used to be a good guide in the learners area about the control run and how it works but can't find it so from what I can remember it does use the same data but because the GFS gets a lot of new data fed into it each run none of the data can be considered accurate so the control run changes the data and runs it negative and positive to try and limit the mistakes.

http://www.netweathe.../ensembles1.pdf

Edited January 3, 2013 by Coast

[Paul_1978]

The weather Outlook, in their update today, does not share the optomism of some who are posting on this discussion forum:

http://www.theweatheroutlook.com/

I would tend to agree.

Why would you tend to agree?

[lord stratus]

I've just seen Brian Gaze's comments regarding the up coming cold spell. Worded very carefully because even if we get the coldest easterly ever recorded, he will be able to argue that the UK missed the coldest temps because it was colder in Scandinavia, Poland etc.

I expect his views to change by 15th January.

[chionomaniac]

I think that we should keep to what the models are suggesting and not what other sites forecasters are making of the upcoming possibilities. If anyone would like to disagree with Brian Gazes assessment, then I am sure that he will be all too pleased to hear your views about this on TWO.

In the meantime let's stick to the output. Thanks.

[Iceaxecrampon]

Here it comes - should liven the forum up....

Much too brief though on this run.

Ian

[SandraD77]

Simon Keeling suggesting that cooler conditions might not make an appearance until late in the month and he's not convinced they'll be widespread http://www.weatherweb.net/wxwebtv2.php.

Followed him all last winter and he was pretty spot on - he neither cold nor mild ramps, just says as it is and provides good reasoning for his musings! Equally Peter O'Donnell issued his winter forecast in September and it's been pretty spot on to date (even predicting the really windy period following xmas) and he's suggesting that winter will arrive in Feb as opposed to Jan http://www.meteotimes.net/2012/09/peter-odonnells-winter-2012-13-forecast.html. His daily forecasts are still suggesting late Jan to Early Feb before we see any sustained cold! http://www.meteotimes.net/2012/08/peter-odonnells-long-range-weather.html

[syed2878]

guys 1qs frm me.if the 06z is so poor y do the noaa use it in their forecast discussions? I have a bit mor confidence in the up and coming patern change af hearing ian f's thorts frm uk.met.

[Coast]

New thread opening shortly folks!

[Radiating Dendrite]

guys 1qs frm me.if the 06z is so poor y do the noaa use it in their forecast discussions? I have a bit mor confidence in the up and coming patern change af hearing ian f's thorts frm uk.met.

It's not poor, just has slightly worse verification rates than the other runs (though the margins are tiny).

NOAA comment on it because it is still very helpful in highlighting developments that they use in their forecasts.

[fergieweather]

Just an addition re current viewpoint from Exeter - I can't offer all the detail regarding their modelling on this I'm afraid, but can paraphrase current thoughts just given to me as follows, to simplify for those of you who might be new to an understanding of where we might be heading in these circumstances:

"At the moment it (SSW) is starting to have an effect at the top of the modelled atmosphere but not yet propagating down to the surface. It’s being monitored with interest and we’ll see what happens there...." (then on the issue of impact upon current model ouput / reliability): ".....Logic suggests it could make things less predictable in mesoscale terms through NWP output, simply because if a blocking high does develop, the position of it could have anything between a huge and a negligible effect on e.g. the UK’s weather...."

[fergieweather]

^{PS new} UKMO^{-GM just arriving and less progressive on this run}

Edited January 3, 2013 by fergieweather

[Grimsby Snow Lover]

^{PS new} UKMO^{-GM just arriving and less progressive on this run}

Hi Ian, what does less progressive mean? Thanks GSL

[Tom Jarvis]

^{PS new} UKMO^{-GM just arriving and less progressive on this run}

is this a good or bad thing sorry new to this??

[Coast]

OK, all bright and shiny, here's a new thread - remember please stick to the topic title